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Neuroinformation Docosahexaenoic acid (DHA) Reviews: 2005 Young, G. and J. Conquer (2005). "Omega-3 fatty acids and neuropsychiatric disorders." Reprod Nutr Dev 45(1): 1-28. Epidemiological evidence suggests that dietary consumption of the long chain omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), commonly found in fish or fish oil, may modify the risk for certain neuropsychiatric disorders. As evidence, decreased blood levels of omega-3 fatty acids have been associated with several neuropsychiatric conditions, including Attention Deficit (Hyperactivity) Disorder, Alzheimer's Disease, Schizophrenia and Depression. Supplementation studies, using individual or combination omega-3 fatty acids, suggest the possibility for decreased symptoms associated with some of these conditions. Thus far, however, the benefits of supplementation, in terms of decreasing disease risk and/or aiding in symptom management, are not clear and more research is needed. The reasons for blood fatty acid alterations in these disorders are not known, nor are the potential mechanisms by which omega-3 fatty acids may function in normal neuronal activity and neuropsychiatric disease prevention and/or treatment. It is clear, however, that DHA is the predominant n-3 fatty acid found in the brain and that EPA plays an important role as an anti-inflammatory precursor. Both DHA and EPA can be linked with many aspects of neural function, including neurotransmission, membrane fluidity, ion channel and enzyme regulation and gene expression. This review summarizes the knowledge in terms of dietary omega-3 fatty acid intake and metabolism, as well as evidence pointing to potential mechanisms of omega-3 fatty acids in normal brain functioning, development of neuropsychiatric disorders and efficacy of omega-3 fatty acid supplementation in terms of symptom management.
Yoshizawa, K. and A. Tsubura (2005). "[Characteristics of N-methyl-N-nitrosourea-induced retinal degeneration in animals and application for the therapy of human retinitis pigmentosa]." Nippon Ganka Gakkai Zasshi 109(6): 327-37. BACKGROUND: Retinitis pigmentosa(RP) is a human disease characterized by loss of photoreceptor cells, especially rods, leading to visual disturbance and eventually to blindness. Effective treatment for RP control is still unavailable. The establishment of reliable animal models is essential for a better understanding of this disease, and for the development of therapeutic intervention. Here we summarize the establishment of N-methyl-N-nitrosourea (MNU)-induced retinal degeneration in animals, and success in disease control using this model. RESULTS: Retinal damage induced by MNU was highly reproducible and involved photoreceptor cell loss. It was obvious in all animals at approximately 7 days following a single systemic administration of MNU to adult mice (60 mg/kg), rats (60-75 mg/kg), hamsters (90 mg/kg), shrews (65 mg/kg), and monkeys (40 mg/kg). Extensive investigation in the rats revealed that MNU-induced photoreceptor cell loss was due to apoptosis with a decrease of Bcl-2 protein, increase of Bax protein, and activation of caspase families. Therapeutic to control MNU-induced photoreceptor cell loss in rats was evaluated with caspase-3 inhibitor (Ac-DEVD-CHO), nicotinamide(NAM), and docosahexaenoic acid(DHA); 4,000ng Ac-DEVD-CHO injected intravitreally 0 and 10 h after MNU suppressed disease progression, 25-1,000 mg/kg NAM subcutaneously injected concurrently or subsequently to MNU reversed retinal damage, and dietary supplementation of 9.5% DHA counteracted photoreceptor cell loss. CONCLUSION: Although the mechanisms triggering pathogenesis and the apoptotic cascade may differ between animals and humans, MNU-induced retinal degeneration is caused by photoreceptor cell apoptosis. Thus, suppression of MNU-induced photoreceptor cell apoptosis in animals may provide therapeutic information for RP control in humans.
Woods, M. N. (2005). "Role of n-3 fatty acids in prevention of disease complications in patients with HIV." Nutr Clin Care 8(1): 24-30. Hypertriglyceridemia and insulin resistance have been seen in patients with HIV. Beneficial effects of the n-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have been reported for these conditions. One study of n-3 fatty acid supplementation in patients with HIV reported a decrease in serum triglyceride levels. These marine fatty acids appear to be working at a number of sites to achieve an improvement in lipid metabolism and insulin sensitivity. There is disagreement about the amount of n-3 fatty acids needed to achieve different effects and about the optimal ratio of dietary n-6 and n-3 fatty acids.
Van Biervliet, S., J. P. Van Biervliet, et al. (2005). "Docosahexaenoic acid trials in cystic fibrosis: a review of the rationale behind the clinical trials." J Cyst Fibros 4(1): 27-34.
Thiebaut, A. C., V. Chajes, et al. (2005). "[Unsaturated fatty acids intake and breast cancer risk: epidemiological data review]." Bull Cancer 92(7): 658-69. The relationship between fatty acids and breast cancer has been debated for long, because of the high frequency of breast cancer and the contradictory results from the numerous studies devoted to this issue. The present review includes case-control and prospective studies, according to specified methodological criteria, which estimated the exposure to monounsaturated fatty acids (MUFA) and n-6 and n-3 polyunsaturated fatty acids (PUFA) using dietary questionnaires or markers (plasma, erythrocytes, adipose tissue). The relationship between MUFA intake and breast cancer risk seems to depend on the contributing food : neutral or beneficial for vegetable oil, rather deleterious for animal products. Contrary to data from animal experiments, human studies do not show an increase of breast cancer risk with n-6 PUFA intake. Estimating the risk associated with alpha-linolenic acid appears difficult due to the incompleteness of food composition tables and studies on biomarkers remain few. The same applies to long-chain n-3 PUFA despite the suggestion of a decrease in risk, in agreement with animal studies. However, it is difficult in human to disentangle the effect of nutrient intake from that of contributing foods or even nutritional profile.
Stillwell, W., S. R. Shaikh, et al. (2005). "Docosahexaenoic acid affects cell signaling by altering lipid rafts." Reprod Nutr Dev 45(5): 559-79. With 22 carbons and 6 double bonds docosahexaenoic acid (DHA) is the longest and most unsaturated fatty acid commonly found in membranes. It represents the extreme example of a class of important human health promoting agents known as omega-3 fatty acids. DHA is particularly abundant in retinal and brain tissue, often comprising about 50% of the membrane's total acyl chains. Inadequate amounts of DHA have been linked to a wide variety of abnormalities ranging from visual acuity and learning irregularities to depression and suicide. The molecular mode of action of DHA, while not yet understood, has been the focus of our research. Here we briefly summarize how DHA affects membrane physical properties with an emphasis on membrane signaling domains known as rafts. We report the uptake of DHA into brain phosphatidylethanolamines and the subsequent exclusion of cholesterol from the DHA-rich membranes. We also demonstrate that DHA-induced apoptosis in MDA-MB-231 breast cancer cells is associated with externalization of phosphatidylserine and membrane disruption ("blebbing"). We conclude with a proposal of how DHA incorporation into membranes may control cell biochemistry and physiology.
Singh, S. P., X. R. Zhou, et al. (2005). "Metabolic engineering of new fatty acids in plants." Curr Opin Plant Biol 8(2): 197-203. Metabolic engineering of plants to express high levels of new fatty acids that are of nutritional and industrial importance has proven to be highly challenging. Significant advances have been made recently, however, particularly in the development of the first plant oils to contain long-chain polyunsaturated fatty acids, such as arachidonic acid, eicosapentaenoic acid and docosahexaenoic acid. Methods of increasing the accumulation of Delta12-modified fatty acids synthesized by transgenically expressed FAD2-like enzymes have also been investigated. Biochemical analyses of plants that express these introduced fatty-acid metabolic pathways have highlighted the central importance of ensuring the removal of novel fatty acids from their site of synthesis on phosphatidylcholine to enable their further modification, exclusion from membrane lipids and accumulation in seed triacylglycerols.
Serhan, C. N. (2005). "Novel eicosanoid and docosanoid mediators: resolvins, docosatrienes, and neuroprotectins." Curr Opin Clin Nutr Metab Care 8(2): 115-21. PURPOSE OF REVIEW: It is well known that arachidonic acid is the precursor to potent mediators. Many clinical studies suggest that omega-3 polyunsaturated fatty acids such as eicosapentaenoic acid and docosahexaenoic acid have beneficial actions in human diseases. The molecular basis of these actions remains of interest. RECENT FINDINGS: These demonstrate that eicosapentaenoic acid and docosahexaenoic acid are precursors to potent (nM range) bioactive mediators that possess both anti-inflammatory and protective properties. These mediators were coined resolvins, docosatrienes, and protectins as general classes, since each possesses unique chemical structures that are features of the new chemical classes and are biosynthesized by new pathways. Resolvins, discovered first, were identified during the resolution phase of acute inflammation; hence the term resolution interaction products, because they are also biosynthesized by human cells via cell-cell interactions. Docosatrienes contain conjugated triene structures generated from docosahexaenoic acid as a defining feature. The protectins comprise docosatrienes and resolvins of the D series that are both neuroprotective and anti-inflammatory. Aspirin impacts on these new pathways by triggering formation of their epimers (i.e. R isomers). SUMMARY: In view of the many beneficial actions attributed to omega-3 dietary supplementation, identification of novel potent mediators from omega-3 that are both anti-inflammatory and protective may have wide implications.
Rodriguez-Cruz, M., A. R. Tovar, et al. (2005). "[Molecular mechanisms of action and health benefits of polyunsaturated fatty acids]." Rev Invest Clin 57(3): 457-72. Essential polyunsaturated fatty acids (PUFAs), linoleic acid n6 (LA) and linolenic acid (ALA) n3 obtained from the diet are precursors of the long-chain polyunsaturated fatty acids (Lc-PUFAs) arachidonic acid (AA) and docosahexaenoic acid (DHA) respectively. Consumption of PUFAs is related with a better neurological and cognitive development in newborns. It has been demonstrated that consumption of n-6 and n-3 PUFAs decreases blood triglycerides by increasing fatty acid oxidation through activation of PPARalpha or by reducing the activation of SREBP-1 inhibiting lipogenesis. Dietary PUFAs activate PPARalpha and PPARgamma increasing lipid oxidation, and decreasing insulin resistance leading in a reduction of hepatic steatosis. Beneficial effects of PUFAs have been observed in humans and in animals models of diabetes, obesity, cancer, and cardiovascular diseases. It is important to promote the consumption of PUFAs. Main food sources of PUFAs n-6 are corn, soy and safflower oil, and for PUFAs n-3 are fish, soy, canola oil and, flaxseed. Finally FAO/WHO recommends an optimal daily intake of n6/n3 of 5-10:1.
Roberts, L. J., 2nd, J. P. Fessel, et al. (2005). "The biochemistry of the isoprostane, neuroprostane, and isofuran Pathways of lipid peroxidation." Brain Pathol 15(2): 143-8. Isoprostanes are prostaglandin-like compounds that are formed non-enzymatically by free radical-catalyzed peroxidation of arachidonic acid (C20:4omega6). Intermediates in the pathway of the formation of isoprostanes are labile prostaglandin H2-like bicyclic endoperoxides (H2-isoprostanes). H2-isoprostanes are reduced to form F-ring isoprostanes (F2-isoprostanes), but they also undergo chemical rearrangement in vivo to form E2- and D2-isoprostanes, isothromboxanes, and highly reactive acyclic y-ketoaldehdyes (isoketals). E2- and D2-isoprostanes also undergo dehydration in vivo to form cyclopentenone A2- and J2-isoprostanes. Docosahexaenoic acid (C22:6omega3) is highly enriched in neurons in the brain and is highly susceptible to oxidation. Free radical-catalyzed oxidation of docosahexaenoic acid results in the formation of isoprostane-like compounds (neuroprostanes). F4-, D4-, E4-, A4-, and J4-neuroprostanes and neuroketals have all been shown to be produced in vivo. In addition, we recently discovered a new pathway of lipid peroxidation that forms compounds with a substituted tetrahydrofuran ring (isofurans). Oxygen concentration differentially modulates the formation of isoprostanes and isofurans. As oxygen concentrations increase, the formation of isofurans is favored whereas the formation of isoprostanes becomes disfavored.
Plat, J. and R. P. Mensink (2005). "Food components and immune function." Curr Opin Lipidol 16(1): 31-7. PURPOSE OF REVIEW: Enhancing immune function or alternatively dampening inflammatory processes by specific food components has received a lot of interest. The purpose of this review is to summarize recent findings with the emphasis on underlying mechanisms. RECENT FINDINGS: Dietary beta-glucans are relatively new candidates in the field of immune modulation by diet. In-vitro and animal studies suggest that beta-glucans shift inflammatory profiles to a Th1 type, which may enhance resistance against bacterial and parasitic infections. Regarding polyunsaturated fatty acids, there is evidence that n-3 fatty acids from fish oils (eicosapentaenoic acid and docosahexaenoic acid) dampen inflammatory responses. Whether eicosapentaenoic acid or docosahexaenoic acid is responsible for this phenomenon remains controversial. It is also inconclusive whether the plant-derived n-3 fatty acid alpha-linolenic acid has the same antiinflammatory effects as observed for fish oils. Saturated fatty acids may activate toll-like receptors and consequently the inflammatory pathway. The effect of total fat intake is controversial, since high-fat diets have been found to suppress immune function, while also improving intestinal barrier function. Finally, Gingko biloba was found to lower nuclear factor kappaB and activator protein 1 activation, possibly due to its high content of polyphenols. SUMMARY: In this review we discuss the nutritional components able to enhance immune function or show antiinflammatory effects. It can be concluded that diet certainly has the potential to direct immune responses. Apart from studies on fish oils, however, evidence from human studies is limited.
Peet, M. and C. Stokes (2005). "Omega-3 fatty acids in the treatment of psychiatric disorders." Drugs 65(8): 1051-9. The importance of omega-3 fatty acids for physical health is now well recognised and there is increasing evidence that omega-3 fatty acids may also be important to mental health. The two main omega-3 fatty acids in fish oil, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have important biological functions in the CNS. DHA is a major structural component of neuronal membranes, and changing the fatty acid composition of neuronal membranes leads to functional changes in the activity of receptors and other proteins embedded in the membrane phospholipid. EPA has important physiological functions that can affect neuronal activity. Epidemiological studies indicate an association between depression and low dietary intake of omega-3 fatty acids, and biochemical studies have shown reduced levels of omega-3 fatty acids in red blood cell membranes in both depressive and schizophrenic patients.Five of six double-blind, placebo-controlled trials in schizophrenia, and four of six such trials in depression, have reported therapeutic benefit from omega-3 fatty acids in either the primary or secondary statistical analysis, particularly when EPA is added on to existing psychotropic medication. Individual clinical trials have suggested benefits of EPA treatment in borderline personality disorder and of combined omega-3 and omega-6 fatty acid treatment for attention-deficit hyperactivity disorder. The evidence to date supports the adjunctive use of omega-3 fatty acids in the management of treatment unresponsive depression and schizophrenia. As these conditions are associated with increased risk of coronary heart disease and diabetes mellitus, omega-3 fatty acids should also benefit the physical state of these patients. However, as the clinical research evidence is preliminary, large, and definitive randomised controlled trials similar to those required for the licensing of any new pharmacological treatment are needed.
Osawa, T. and Y. Kato (2005). "Protective role of antioxidative food factors in oxidative stress caused by hyperglycemia." Ann N Y Acad Sci 1043: 440-51. Hyperglycemia causes the autoxidation of glucose, glycation of proteins, and the activation of polyol metabolism. These changes accelerate generation of reactive oxygen species (ROS) and increases in oxidative chemical modification of lipids, DNA, and proteins in various tissues. Oxidative stress may play an important role in the development of complications in diabetes such as lens cataracts, nephropathy, and neuropathy. Glycation reactions, especially Maillard reactions, occur in vivo as well as in vitro and are associated with the chronic complications of diabetes mellitus and aging and age-related diseases by increases in oxidative chemical modification of lipids, DNA, and proteins. In particular, long-lived proteins such as lens crystallines, collagens, and hemoglobin may react with reducing sugars to form advanced glycation end products (AGEs). Recently, we found a novel type of AGE, named MRX, and we found that MRX is a good biomarker for detecting oxidative stress produced during Maillard reaction. We also examined in detail the role of lipid peroxidation reaction in hyperglycemia and found that hexanoyl modification formed by the reaction of oxidized lipids and proteins must be important for oxidative stress. Detailed analyses of the formation mechanism of hexanoyl lysine (HEL) moiety in proteins were conducted, and excretion of HEL into urine was quantified by using LC/MS/MS. Macrophages and neutrophils play an important role in oxidative stress during hyperglycemia, and we determined that oxidatively modified tyrosines are a good biomarker for formation of oxidative stress at an early stage. Immunochemical analyses by application of monoclonal antibodies specific to lipid hydroperoxide-modified proteins produced by polyunsaturated fatty acids including docosahexaenoic acid (DHA) in oxidative stress caused by hyperglycemia were conducted, and the relationship between glycation and lipid peroxidation reactions both by chemical and immunochemical approaches are discussed. Recently, we put much more focus on dietary antioxidants for prevention of diabetic complications. Curcuminoids, the main yellow pigments in Curcuma longa (turmeric), have been used widely and for a long time in the treatment of sprain and inflammation in indigenous medicine. Curcumin is the main component of turmeric, and two minor components are also present as the curcuminoids. Curcuminoids possess antioxidant activity. Protective effects of curcumin (U1) and one of its major metabolites, tetrahydrocurcumin (THU1), have been examined for development of diabetic cataract in 25% galactose-fed SD rats. Through detailed examination of protective mechanisms of THU1, it was found that THU1 showed that scavenger ROS not only formed during hyperglycemia, but also induced antioxidative enzymes including detoxification enzymes such as glutathine S-transferase. THU1 also showed significant increase of glutathione concentration in the cultured rat lens. Glutathione (gamma-glutamylcysteinyl glycine [GSH]) is thought to be an important factor in cellular function and defense against oxidative stress, and we found that dietary GSH suppresses oxidative stress in vivo in prevention of diabetic complications such as diabetic nephropathy and neuropathy.
Okuyama, H. (2005). "[Need to change the direction of cholesterol-related medication--a problem of great urgency]." Yakugaku Zasshi 125(11): 833-52. The cholesterol hypothesis implies that reducing the intake of saturated fatty acids and cholesterol and increasing that of polyunsaturated fatty acid are effective in lowering serum total cholesterol (TC), and thereby reducing the incidence of coronary heart disease (CHD). However, these dietary recommendations are essentially ineffective in reducing TC in the long run, but rather increase mortality rates from CHD and all causes. The reported "apparent relative risk of high TC in CHD mortality" (the ratio of mortality at the highest/lowest TC levels) varied several-fold among populations studied. The incidence of familial hypercholesterolemia (FH) in a population was proposed to be a critical factor in the observed variability, which could be accounted for by assuming that 1) the high CHD mortality rate in high-TC groups is mainly a reflection of the incidence and severity of FH, and 2) high TC is not a causative factor of CHD in non-FH cases. This interpretation is supported by recent observations that high TC is not positively associated with high CHD mortality rates among general populations more than 40-50 years of age. More importantly, higher TC values are associated with lower cancer and all-cause mortality rates among these populations, in which relative proportions of FH are likely to be low (circa 0.2%). Although the effectiveness of statins in preventing CHD has been accepted in Western countries, little benefit seems to result from efforts to limit dietary cholesterol intake or to TC values to less than approximately 260 mg/dl among the general population and the elderly. Instead, an unbalanced intake of omega6 over omega3 polyunsaturated fats favors the production of eicosanoids, the actions of which lead to the production of inflammatory and thrombotic lipid mediators and altered cellular signaling and gene expression, which are major risk factors for CHD, cancers, and shorter longevity. Based on the data reviewed here, it is urgent to change the direction of current cholesterol-related medication for the prevention of CHD, cancer, and all-cause mortality.
Ohara, K. (2005). "[Omega-3 fatty acids in mood disorders]." Seishin Shinkeigaku Zasshi 107(2): 118-26. The etiology and treatment of mood disorders has not yet been elucidated. Omega (omega)-3 fatty acids are essential fatty acids, which cannot be synthesized in the human body. Eicosapentanoic acid (EPA) and docosahexaenoic acid (DHA) are representative omega-3 fatty acids which are found in fish (eg., mackerel, herring, Chinook salmon) and vegetables (eg., flax, walnut, canola). The peripheral level of EPA and DHA decrease in patients with major depression, and EPA is useful for its treatment. Further research is required on omega-3 fatty acids in patients with mood disorders.
Oh, R. (2005). "Practical applications of fish oil (Omega-3 fatty acids) in primary care." J Am Board Fam Pract 18(1): 28-36. BACKGROUND: Fish oil (Omega-3 fatty acids) has been studied for more than 30 years. However, recent concerns of mercury and environmental toxins have clouded fish oil's potential clinical benefits. This article aims to review practical, evidence-based applications of fish oil for the primary care physician. METHODS: PubMed search using key words 'fish oil,' 'docosahexaenoic,' and 'eicosapentaenoic' in title/abstract. Limited to human clinical trials. Articles were further scanned for relevant sources. RESULTS: For secondary prevention of cardiovascular disease, 1 g of fish oil has shown to reduce overall and cardiovascular mortality, myocardial infarction, and sudden cardiac death. Higher doses may be used for its potent triglyceride-lowering effects and for patients with rheumatoid arthritis to reduce nonsteroidal anti-inflammatory use. Omega-3 fatty acid supplementation of infant formula has shown benefit in infant neural growth and development. With the potential health benefits of fish, women of childbearing age should be encouraged to eat 1 to 2 low-mercury fish meals per week. CONCLUSIONS: Fish oil has numerous practical applications for the primary care physician. Understanding the diverse clinical research of Omega-3 fatty acids and fish oil is important in determining its role in primary care practices.
Musiek, E. S., G. L. Milne, et al. (2005). "Cyclopentenone eicosanoids as mediators of neurodegeneration: a pathogenic mechanism of oxidative stress-mediated and cyclooxygenase-mediated neurotoxicity." Brain Pathol 15(2): 149-58. The activation of cyclooxygenase enzymes in the brain has been implicated in the pathogenesis of numerous neurodegenerative conditions. Similarly, oxidative stress is believed to be a major contributor to many forms of neurodegeneration. These 2 distinct processes are united by a common characteristic: the generation of electrophilic cyclopentenone eicosanoids. These cyclopentenone compounds are defined structurally by the presence of an unsaturated carbonyl moiety in their prostane ring, and readily form Michael adducts with cellular thiols, including those found in glutathione and proteins. The cyclopentenone prostaglandins (PGs) PGA2, PGJ2, and 15-deoxy-delta(12,14) PGJ2, enzymatic products of cyclooxygenase-mediated arachidonic acid metabolism, exert a complex array of potent neurodegenerative, neuroprotective, and anti-inflammatory effects. Cyclopentenone isoprostanes (A2/J2-IsoPs), products of non-enzymatic, free radical-mediated arachidonate oxidation, are also highly bioactive, and can exert direct neurodegenerative effects. In addition, cyclopentenone products of docosahexaenoic acid oxidation (cyclopentenone neuroprostanes) are also formed abundantly in the brain. For the first time, the formation and biological actions of these various classes of reactive cyclopentenone eicosanoids are reviewed, with emphasis on their potential roles in neurodegeneration. The accumulating evidence suggests that the formation of cyclopentenone eicosanoids in the brain may represent a novel pathogenic mechanism, which contributes to many neurodegenerative conditions.
Moyad, M. A. (2005). "An introduction to dietary/supplemental omega-3 fatty acids for general health and prevention: part I." Urol Oncol 23(1): 28-35. The correction of a subtle nutritional deficiency that may reduce the risk of a future chronic disease is indeed a challenge. However, some specific examples in the past, such as the addition of folic acid to prevent neural tube defects and calcium and vitamin D to prevent osteoporosis, should provide some encouragement that some conditions can be prevented with the appropriate addition of a deficient compound. One of the most intriguing current and future impacts on public health may come from a greater intake of omega-3 fatty acids such as alpha-linolenic acid (ALA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA). The omega-3 fatty acids continue to accumulate research that suggests that may prevent a variety of diverse chronic diseases and potentially some acute clinical scenarios. In Part 1 of this manuscript the potential for these compounds to prevent certain cardiovascular conditions are discussed. In Part 2 the potential for an impact in arthritis, numerous areas of cancer research, depression, maternal and child health, neurological diseases, osteoporosis, and other medical disciplines are also briefly covered. The future appears bright for these agents, but specifically which conditions, who qualifies, testing, frequency, adequate sources, future trials and numerous other questions need to be addressed and answered before the potential impact can catch up to the recent hype.
Moyad, M. A. (2005). "An introduction to dietary/supplemental omega-3 fatty acids for general health and prevention: part II." Urol Oncol 23(1): 36-48. The correction of a subtle nutritional deficiency that may reduce the risk of a future chronic disease is indeed a challenge. However, some specific examples in the past, such as the addition of folic acid to prevent neural tube defects and calcium and vitamin D to prevent osteoporosis, should provide some encouragement that some conditions can be prevented with the appropriate addition of a deficient compound. One of the most intriguing current and future impacts on public health may come from a higher intake of omega-3 fatty acids, such as alpha-linolenic acid (ALA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA). The omega-3 fatty acids continue to accumulate research that suggests that they may prevent a variety of diverse chronic diseases and potentially some acute clinical scenarios. In the first part of this article, the potential for these compounds to prevent certain cardiovascular conditions are discussed. In the second part, the potential for an impact in arthritis, numerous areas of cancer research, depression, maternal and child health, neurologic diseases, osteoporosis, and other medical disciplines are also briefly covered. The future appears bright for these agents, but specifically which conditions, who qualifies, testing, frequency, adequate sources, future trials, and numerous other questions need to be addressed and answered before the potential impact can catch up to the recent hype.
Montine, T. J. and J. D. Morrow (2005). "Fatty acid oxidation in the pathogenesis of Alzheimer's disease." Am J Pathol 166(5): 1283-9. Alzheimer's disease (AD) is the most common dementing illness of the elderly and is a mounting public health problem. Pharmacoepidemiological data, analytical data from human tissue and body fluids, and mechanistic data mostly from murine models all have implicated oxidation products of two fatty acids, arachidonic acid (AA) and docosahexaenoic acid (DHA), in the pathogenesis of neurodegeneration. Here we review the biochemistry of AA and DHA oxidation, both enzyme-catalyzed and free radical mediated, and summarize those studies that have investigated these oxidation products as effectors of neurodegeneration and biomarkers of AD. Given the evolving appreciation for toxicity associated with current pharmaceuticals used to block AA and DHA oxidation, we close by speculating on likely areas of future research directed at suppressing this facet of neurodegeneration. If successful, these interventions are unlikely to cure AD, but may check its explosive growth and hopefully reduce its incidence and prevalence in the elderly.
Milne, G. L., E. S. Musiek, et al. (2005). "The cyclopentenone (A2/J2) isoprostanes--unique, highly reactive products of arachidonate peroxidation." Antioxid Redox Signal 7(1-2): 210-20. Cyclopentenone (A2/J2) isoprostanes (IsoPs) are a group of prostaglandin (PG)-like compounds generated in vivo from the free radical-induced peroxidation of arachidonic acid. Unlike other classes of IsoPs, cyclopentenone IsoPs contain highly reactive unsaturated carbonyl moieties on the prostane ring analogous to cyclooxygenase-derived PGA2 and PGJ2 that readily adduct relevant biomolecules such as thiols via Michael addition. The purpose of this review is to summarize our knowledge of the A2/J2-IsoPs. As a starting point, we will briefly discuss the formation and biological properties of PGA2 and PGJ2. Next, we will review studies definitively showing that cyclopentenone IsoPs are formed in large amounts in vivo. This is in marked contrast to cyclopentenone PGs, for which little evidence exists that they are endogenously produced. Subsequently, we will discuss studies related to the chemical syntheses of the 15-A2-IsoP series of cyclopentenone IsoPs. The successful synthesis of these compounds provides the recent impetus to explore the metabolism and biological properties of A-ring IsoPs, particularly as modulators of inflammation, and this work will be discussed. Finally, the formation of cyclopentenone IsoP-like compounds from other fatty acids such as linolenic acid and docosahexaenoic acid will be detailed.
Mickleborough, T. D. (2005). "Dietary omega-3 polyunsaturated fatty acid supplementation and airway hyperresponsiveness in asthma." J Asthma 42(5): 305-14. Asthma prevalence continues to increase despite the progress that has been made in the treatment options for asthma. Alternative treatment therapies that reduce the dose requirements of pharmacological interventions would be beneficial, and could potentially reduce the public health burden of this disease. There is accumulating evidence that dietary modification has potential to influence the severity of asthma and reduce the prevalence and incidence of this condition. A possible contributing factor to the increased incidence of asthma in Western societies may the consumption of a pro-inflammatory diet. In the typical Western diet, 20-25-fold more omega (n)-6 polyunsaturated fatty acids (PUFA) than n-3 PUFA are consumed, which results in the release of pro-inflammatory arachidonic acid metabolites. Eicosapentaenoic acid and docosahexaenoic acid are n-3 PUFA derived from fish oil that competitively inhibit n-6 PUFA arachidonic acid (AA) metabolism and this reduce the generation of pro-inflammatory 4-series leukotrienes (LTs) and 2-series prostaglandins (PGs) and production of cytokines from inflammatory cells. These data are consistent with the proposed pathway by which dietary intake of n-3 PUFA modulates lung disease. This article will review the existing information concerning the relationship between n-3 PUFA supplementation and airway hyperresponsiveness in asthma. It includes studies assessing the efficacy of n-3 PUFA supplementation in exercise-induced bronchoconstriction. This review will also address the question as to whether supplementing the diet with n-3 PUFA represents a viable alternative treatment regimen for asthma.
Meng, L. P., J. Zhang, et al. (2005). "[Relationship between maternal DHA intake and DHA status and development of fetus and infant]." Wei Sheng Yan Jiu 34(2): 231-3. The important physiological function of docosahexaenoic acid (DHA) is being the focus of nutriology fields. The DHA status of pregnant and lactation women, who are the main nutrition provider for fetus and infants, had an important effect on DHA nutrition and development of their fetus and infants. The infants whose mother had a supplement of DHA during pregnancy and lactation have higher blood DHA level and better development results of body, visual acuity and intelligence. This paper reviewed the recent international research data on the relationship between maternal DHA intake and DHA status and development of fetus and infant.
McCann, J. C. and B. N. Ames (2005). "Is docosahexaenoic acid, an n-3 long-chain polyunsaturated fatty acid, required for development of normal brain function? An overview of evidence from cognitive and behavioral tests in humans and animals." Am J Clin Nutr 82(2): 281-95. This review is part of a series intended for nonspecialists that will summarize evidence relevant to the question of whether causal relations exist between micronutrient deficiencies and brain function. Here, we focus on experiments that used cognitive or behavioral tests as outcome measures in experimental designs that were known to or were likely to result in altered brain concentrations of the n-3 fatty acid docosahexaenoic acid (DHA) during the perinatal period of "brain growth spurt." Experimental designs reviewed include observational breastfeeding studies and randomized controlled trials in humans and studies in rodents and nonhuman primates. This review is based on a large number of expert reviews and commentaries and on some 50 recent studies in humans and animals that have not yet been included in published reviews. Expert opinion regarding the strengths and weaknesses of the major experimental systems and uncertainties associated with interpreting results is summarized. On the basis of our reading of this literature, we conclude that evidence from several types of studies, particularly studies in animals, suggests that, within the context of specific experimental designs, changes in brain concentrations of DHA are positively associated with changes in cognitive or behavioral performance. Additional experimental information required to conclude that a causal association exists is discussed, as are uncertainties associated with applying results from specific experimental designs to the question of whether infant formula should be supplemented with DHA.
Matthan, N. R., H. Jordan, et al. (2005). "A systematic review and meta-analysis of the impact of omega-3 fatty acids on selected arrhythmia outcomes in animal models." Metabolism 54(12): 1557-65. Epidemiological studies and clinical trials report the beneficial effects of fish or fish oil consumption on cardiovascular disease outcomes including sudden death. We performed a systematic review of the literature on controlled animal studies that assessed the effects of omega-3 fatty acids on selected arrhythmia outcomes. On the basis of predetermined criteria, 27 relevant animal studies were identified; 23 of these were feeding studies, and 4 were infusion studies. Across species, fish oil, eicosapentaenoic acid, and/or docosahexaenoic acid appear to have beneficial effects on ventricular tachycardia (VT) and fibrillation (VF) in ischemia- but not reperfusion-induced arrhythmia models; no effect on the incidence of death and infarct size; and inconsistent results with regard to arrhythmia score, VF threshold, ventricular premature beats or length of time in normal sinus rhythm, compared to omega-6, monounsaturated, or saturated fatty acids, and no treatment controls. In a meta-analysis of 13 studies using rat models, fish oil but not alpha-linolenic acid supplementation showed a significant protective effect for ischemia- and reperfusion-induced arrhythmias by reducing the incidence of VT and VF. It is not known whether omega-3 fatty-acid supplementation has antiarrhythmic effects in other disease settings not related to ischemia.
Marszalek, J. R. and H. F. Lodish (2005). "Docosahexaenoic acid, fatty acid-interacting proteins, and neuronal function: breastmilk and fish are good for you." Annu Rev Cell Dev Biol 21: 633-57. In contrast to other tissues, the nervous system is enriched in the polyunsaturated fatty acids (PUFAs): arachidonic acid (AA, 20:4 n-6) and docosahexaenoic acid (DHA, 22:6 n-3). Despite their abundance in the nervous system, AA and DHA cannot be synthesized de novo by mammals; they, or their precursors, must be ingested from dietary sources and transported to the brain. During late gestation and the early postnatal period, neurodevelopment is exceptionally rapid, and substantial amounts of PUFAs, especially DHA, are critical to ensure neurite outgrowth as well as proper brain and retina development. Here, we review the various functions of DHA in the nervous system, the proteins involved in its internalization and metabolism into phospholipids, and its relationship to several neurological disorders, including Alzheimer's disease and depression.
Kidd, P. M. (2005). "Neurodegeneration from mitochondrial insufficiency: nutrients, stem cells, growth factors, and prospects for brain rebuilding using integrative management." Altern Med Rev 10(4): 268-93. Degenerative brain disorders (neurodegeneration) can be frustrating for both conventional and alternative practitioners. A more comprehensive, integrative approach is urgently needed. One emerging focus for intervention is brain energetics. Specifically, mitochondrial insufficiency contributes to the etiopathology of many such disorders. Electron leakages inherent to mitochondrial energetics generate reactive oxygen free radical species that may place the ultimate limit on lifespan. Exogenous toxins, such as mercury and other environmental contaminants, exacerbate mitochondrial electron leakage, hastening their demise and that of their host cells. Studies of the brain in Alzheimer's and other dementias, Down syndrome, stroke, Parkinson's disease, multiple sclerosis, amyotrophic lateral sclerosis, Huntington's disease, Friedreich's ataxia, aging, and constitutive disorders demonstrate impairments of the mitochondrial citric acid cycle and oxidative phosphorylation (OXPHOS) enzymes. Imaging or metabolic assays frequently reveal energetic insufficiency and depleted energy reserve in brain tissue in situ. Orthomolecular nutrients involved in mitochondrial metabolism provide clinical benefit. Among these are the essential minerals and the B vitamin group; vitamins E and K; and the antioxidant and energetic cofactors alpha-lipoic acid (ALA), ubiquinone (coenzyme Q10; CoQ10), and nicotinamide adenine dinucleotide, reduced (NADH). Recent advances in the area of stem cells and growth factors encourage optimism regarding brain regeneration. The trophic nutrients acetyl L-carnitine (ALCAR), glycerophosphocholine (GPC), and phosphatidylserine (PS) provide mitochondrial support and conserve growth factor receptors; all three improved cognition in double-blind trials. The omega-3 fatty acid docosahexaenoic acid (DHA) is enzymatically combined with GPC and PS to form membrane phospholipids for nerve cell expansion. Practical recommendations are presented for integrating these safe and well-tolerated orthomolecular nutrients into a comprehensive dietary supplementation program for brain vitality and productive lifespan.
Innis, S. M. (2005). "Essential fatty acid transfer and fetal development." Placenta 26 Suppl A: S70-5. Docosahexaenoic acid (22:6n-3) and arachidonic acid (20:4n-6) are important structural components of the central nervous system. These fatty acids are transferred across the placenta, and are accumulated in the brain and other organs during fetal development. Depletion of 22:6n-3 from the retina and brain results in reduced visual function and learning deficits: these may involve critical roles of 22:6n-3 in membrane-dependent signaling pathways and neurotransmitter metabolism. Transfer of 22:6n-3 across the placenta involves specific binding and transfer proteins that facilitate higher concentrations of 22:6n-3 and 20:4n-6, but lower linoleic acid (18:2n-6) in fetal compared with maternal plasma, or in the breast-fed or formula-fed infant. However, human and animal studies both demonstrate that maternal diet impacts fetal 22:6n-3 and 20:4n-6 accretion. After birth, parenteral lipid, human milk and infant formula feeding all result in a marked decrease in plasma 22:6n-3 and 20:4n-6 and an increase in 18:2n-6. Estimation of fetal tissue fatty acid accretion suggests that current preterm infant feeds are unlikely to meet in utero rates of 22:6n-3 accretion. Consideration needs to be given to whether fetal plasma 22:6n-3 and 20:4n-6 enrichment and the low 18:2n-6 facilitates accretion of 22:6n-3 and 20:4n-6 in developing tissues.
Heird, W. C. and A. Lapillonne (2005). "The role of essential fatty acids in development." Annu Rev Nutr 25: 549-71. The presence of docosahexaenoic acid (DHA) and arachidonic acid (ARA) in human milk but not in infant formula, coupled with lower plasma and brain lipid contents of DHA in formula-fed than in breast-fed infants and reports of higher IQ in individuals who were breast-fed versus formula-fed as infants, suggest that exogenous DHA (and ARA) may be essential for optimal development. Thus, since 1990, several studies have examined the impact of formulas containing DHA or DHA plus ARA on visual function and neurodevelopmental outcome. Some of these studies have shown benefits but others have not. These results leave largely unanswered the question of whether these fatty acids are beneficial for either the term or preterm infant. However, evidence that preterm infants might benefit is somewhat more convincing than that for term infants. Despite the limited evidence for efficacy, formulas supplemented with DHA and ARA are now available and appear to be safe.
Grynberg, A. (2005). "Effectors of fatty acid oxidation reduction: promising new anti-ischaemic agents." Curr Pharm Des 11(4): 489-509. The heart is a pump, but also a furnace able to produce at each moment a large amount of energy and to adapt fast enough to face the changes in both fuel supply and energy demand. The pharmacological treatment of angina has been largely focused on the "pump" through hemodynamic agents aimed at decreasing cardiac effort to decrease energy demand. A new concept arose focusing the "furnace" through metabolic agents aimed at decreasing the oxygen cost of ATP production. This goal can be achieved by shifting energy production from fatty acid beta-oxidation to glucose oxidation. CPT1 inhibitors were developed to prevent the fatty acid entry into mitochondria but induced cardiac hypertrophy. Regulation of carnitine biology either by carnitine supply or by gamma-butyrobetaine hydroxylase inhibitors have led to controversial data both in pharmacological and clinical concerns. Trimetazidine and ranolazine increase the glucose/fatty acid oxidation balance and exhibit beneficial effects in animal studies as well as in clinical trials, both in monotherapy and in association with a traditional hemodynamic drug. The association of metabolic and hemodynamic agents brings additive benefits in angina, whereas associations of hemodynamics do not. The mechanism of these drugs has not been fully understood in terms of specific target. In animal studies, dietary docosahexaenoic acid allowed similar protection, through a mechanism related to membrane conformation without specific enzymic target. From the mechanistic research published in this field, enough has now been understood to foresee some future possible targets, mainly related to the cardiomyocyte fatty acid metabolism.
Grynberg, A. (2005). "Hypertension prevention: from nutrients to (fortified) foods to dietary patterns. Focus on fatty acids." J Hum Hypertens 19 Suppl 3: S25-33. Diet affects significantly the incidence and severity of cardiovascular diseases and fatty acid intake, in its qualitative as well as quantitative aspects, and influences several risk factors including cholesterol (total, LDL and HDL), triglycerides, platelet aggregation and blood pressure, as evidenced in the 2001 WHO report. This review focuses on the qualitative concern of lipid intake, the various classes of fatty acids of the lipid fraction of the diet, saturated, monounsaturated and polyunsaturated, and their effects on blood pressure. Saturated fat have a bad file and several experimental studies in the rat showed a progressive increase in blood pressure in response to a highly saturated diet. Moreover, a highly saturated diet during gestation led to offspring which, when adults, presented a gender-related hypertension. The mechanism of this effect may be related to the polyunsaturated/saturated ratio (p/s). During the past 20 years, trans fatty acids have been suspected of deleterious health effects, but the investigations have shown that these fatty acids display a biological behaviour close to that of saturated fatty acids (SFA). Moreover, epidemiological investigations did not confirm the relationship between trans fatty acids and cardiovascular pathology. Polyunsaturated fatty acids have been shown to exert a positive action on hypertension. This effect could be attributed to the alteration of the p/s, but mainly to the omega3 polyunsaturated fatty acids (PUFAs). The comparison of several animal models led to the conclusion that long-chain omega3 PUFAs (eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)) can prevent the increase in blood pressure and reduce established hypertension, but the efficient dose remains an object of discussion. Moreover, the two long-chain omega3 PUFAs, EPA and DHA, display specific effects, which vary with the aetiology of hypertension, because their mechanism of action is different. DHA acts on both blood pressure and heart function (heart rate and ECG) and interferes with the adrenergic function. Conversely, EPA, which is not incorporated in cardiac phospholipids, has no effect on the heart and its mechanism of action is largely unknown. Although it is accepted by the scientific community that the intake of EPA and DHA needs to be increased, we will have to discover new ways to do it, since marine products are the main source of these fatty acids, and this source is not inexhaustible.
Fleith, M. and M. T. Clandinin (2005). "Dietary PUFA for preterm and term infants: review of clinical studies." Crit Rev Food Sci Nutr 45(3): 205-29. Human milk contains n-3 and n-6 LCPUFA (long chain polyunsaturated fatty acids), which are absent from many infant formulas. During neonatal life, there is a rapid accretion of AA (arachidonic acid) and DHA (docosahexaenoic acid) in infant brain, DHA in retina and of AA in the whole body. The DHA status of breast-fed infants is higher than that of formula-fed infants when formulas do not contain LCPUFA. Studies report that visual acuity of breast-fed infants is better than that of formula-fed infants, but other studies do not find a difference. Cognitive development of breast-fed infants is generally better, but many sociocultural confounding factors may also contribute to these differences. The effect of dietary LCPUFA on FA status, immune function, visual, cognitive, and motor functions has been evaluated in preterm and term infants. Plasma and RBC FA status of infants fed formulas supplemented with both n-3 and n-6 LCPUFA was closer to the status of breast-fed infants than to that of infants fed formulas containing no LCPUFA. Adding n-3 LCPUFA to preterm-infant formulas led to initial beneficial effects on visual acuity. Few data are available on cognitive function, but it seems that in preterm infants, feeding n-3 LCPUFA improved visual attention and cognitive development compared with infants receiving no LCPUFA. Term infants need an exogenous supply of AA and DHA to achieve similar accretion of fatty acid in plasma and RBC (red blood cell) in comparison to breast-fed infants. Fewer than half of all studies have found beneficial effects of LCPUFA on visual, mental, or psychomotor functions. Improved developmental scores at 18 mo of age have been reported for infants fed both AA and DHA. Growth, body weight, and anthropometrics of preterm and term infants fed formulas providing both n-3 and n-6 LCPUFA fatty acids is similar in most studies to that of infants fed formulas containing no LCPUFA. A larger double-blind multicenter randomized study has recently demonstrated improved growth and developmental scores in a long-term feeding study of preterm infants. Collectively, the body of literature suggests that LCPUFA is important to the growth and development of infants. Thus, for preterm infants we recommend LCPUFA intakes in the range provided by feeding of human milk typical of mothers in Western countries. This range can be achieved by a combination of AA and DHA, providing an AA to DHA ratio of approximately 1.5 and a DHA content of as much as 0.4%. Preterm infants may benefit from slightly higher levels of these fatty acids than term infants. In long-term studies, feeding more than 0.2% DHA and 0.3% AA improved the status of these fatty acids for many weeks after DHA; AA was no longer present in the formula, enabling a DHA and AA status more similar to that of infants fed human milk. The addition of LCPUFA in infant formulas for term infants, with appropriate regard for quantitative and qualitative qualities, is safe and will enable the formula-fed infant to achieve the same blood LCPUFA status as that of the breast-fed infant.
Filburn, C. R. and D. Griffin (2005). "Canine plasma and erythrocyte response to a docosahexaenoic acid-enriched supplement: characterization and potential benefits." Vet Ther 6(1): 29-42. Results of this study confirm that dietary supplementation in dogs with a natural source of omega-3 fatty acids (salmon oil), with a docosahexaenoic acid:eicosapentaenoic acid (DHA:EPA) ratio of 1.5:1, increases plasma and red blood cell levels of these fatty acids. Supplementation with this DHA-enriched oil improves the long-chain polyunsaturated fatty acid omega-6:omega-3 (n-6:n-3) ratio, which may benefit dogs of all ages. Studies describing some of the neurologic, renal, cardiovascular, immune, and musculoskeletal effects of elevated blood levels of n-3 fatty acids, especially DHA, are reviewed. The importance of providing an enriched source of DHA, instead of its shorter precursors, is emphasized.
Feller, S. E. and K. Gawrisch (2005). "Properties of docosahexaenoic-acid-containing lipids and their influence on the function of rhodopsin." Curr Opin Struct Biol 15(4): 416-22. The importance of highly polyunsaturated fatty acids in health and development has been convincingly demonstrated by many studies over the past several decades. The mechanisms by which polyunsaturated lipid species might influence biological function at the molecular level are now attracting considerable attention. The G-protein-coupled receptor rhodopsin and docosahexaenoic acid, the dominant fatty acid in the retinal membrane, provide the best-studied example of protein function being influenced by lipid environment.
Decsi, T. and B. Koletzko (2005). "N-3 fatty acids and pregnancy outcomes." Curr Opin Clin Nutr Metab Care 8(2): 161-6. PURPOSE OF REVIEW: To discuss new data from the literature on the relationship between the supply of n-3 polyunsaturated fatty acids during pregnancy and pregnancy outcomes, evaluated as the fatty acid composition of blood and breast milk, fetal and infantile development and maternal health. RECENT FINDINGS: Supplementation of alpha-linolenic acid in high doses or docosahexaenoic acid in low doses did not result in a significant enhancement of the blood docosahexaenoic acid status of the offspring. In contrast, supplementation of docosahexaenoic acid in relatively high doses led to significant increases in infantile docosahexaenoic acid values and to a significant enhancement of breast milk docosahexaenoic acid content. Electroretinogram data obtained during the first week of life and pattern-reversal visual evoked potentials investigated at 50 and 66 weeks postconception were significantly associated with the docosahexaenoic acid status of the infant at birth. Children whose mothers received docosahexaenoic acid supplementation during pregnancy and lactation scored better in mental processing tests carried out at 4 years than children whose mothers received placebo. SUMMARY: Beneficial health outcomes are more likely to result from supplementation with docosahexaenoic acid itself, rather than its precursor alpha-linolenic acid. Trials have shown that a higher maternal docosahexaenoic acid intake during pregnancy may be favourable for the visual and cognitive development of the offspring. The significant positive association between maternal docosahexaenoic acid intake during pregnancy and the children's mental processing scores at 4 years suggest that optimization of the docosahexaenoic acid status of expectant women may offer long-term developmental benefits to their children.
Das, U. N. (2005). "Long-chain polyunsaturated fatty acids, endothelial lipase and atherosclerosis." Prostaglandins Leukot Essent Fatty Acids 72(3): 173-9. Endothelial lipase (EL), a new member of the lipase gene family, was recently cloned and has been shown to have a significant role in modulating the concentrations of plasma high-density lipoprotein levels (HDL). EL is closely related to lipoprotein and hepatic lipases both in structure and function. It is primarily synthesized by endothelial cells, functions at the cell surface, and shows phospholipase A1 activity. Overexpression of EL decreases HDL cholesterol levels whereas blocking its action increases concentrations of HDL cholesterol. Pro-inflammatory cytokines suppress plasma HDL cholesterol concentrations by enhancing the activity of EL. On the other hand, physical exercise and fish oil (a rich source of eicosapentaenoic acid and docosahexaenoic acid) suppress the activity of EL and this, in turn, enhances the plasma concentrations of HDL cholesterol. Thus, EL plays a critical role in the regulation of plasma HDL cholesterol concentrations and thus modulates the development and progression of atherosclerosis. The expression and actions of EL in specific endothelial cells determines the initiation and progression of atherosclerosis locally explaining the patchy nature of atheroma seen, especially, in coronary arteries. Both HDL cholesterol and EPA and DHA enhance endothelial nitric oxide (eNO) and prostacyclin (PGI2) synthesis, which are known to prevent atherosclerosis. On the other hand, pro-inflammatory cytokines augment free radical generation, which are known to inactivate eNO and PGI2. Thus, interactions between EL, pro- and anti-inflammatory cytokines, polyunsaturated fatty acids, and the ability of endothelial cells to generate NO and PGI2 and neutralize the actions of free radicals may play a critical role in atherosclerosis.
Das, U. N. (2005). "Essential fatty acids and acquired immunodeficiency syndrome." Med Sci Monit 11(6): RA206-211. Acquired immunodeficiency syndrome (AIDS) is caused by human immunodeficiency virus (HIV) that is characterized by profound immunodeficiency, opportunistic infections and Kaposi's sarcoma. As yet no effective therapy is available for AIDS, though retroviral drugs are able to prolong life and contain HIV proliferation to some extent. I propose that essential fatty acids (EFAs) and their metabolites could be useful in the prevention and management of AIDS. Linoleic acid (LA) and arachidonic acid (AA) inactivate enveloped viruses, linolenic acid-enriched macrophages are markedly tumoricidal, EFAs activate macrophages and neutrophils and induce free radical generation; and cytokines bring about some of their actions by inducing the release of EFAs; gamma-linolenic acid (GLA) and eicosapentaenoic acid (EPA) prevent genetic damage and have tumoricidal actions as well; and are relatively non-toxic when administered orally or parentarally over long periods of time. In view of this, I suggest that further studies with regard to the role of GLA, AA, EPA and/or docosahexaenoic acid (DHA) in the pathobiology of AIDS needs to be performed. It is also proposed that possible use of these fatty acids in the prevention and treatment of AIDS needs serious consideration.
Das, U. N. (2005). "Pathophysiology of metabolic syndrome X and its links to the perinatal period." Nutrition 21(6): 762-73. It is proposed that metabolic syndrome X is initiated in the perinatal period as a low-grade systemic inflammatory condition. Increased consumption of energy-dense diets by pregnant women and lactating mothers suppresses the activities of Delta-6 and Delta-5 desaturases not only in maternal tissues but also in fetal liver and the placenta, resulting in decreased plasma and tissue concentrations of long-chain polyunsaturated fatty acids omega-6 arachidonic acid (AA), omega-3 eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA). EPA, DHA, and AA have negative feedback control on tumor necrosis factor-alpha and IL-6 synthesis. Hence, EPA, DHA, and AA deficiencies induced by an energy-dense diet increase generation of tumor necrosis factor-alpha and interleukin-6, markers of inflammation that in turn decrease production of endothelial nitric oxide and adiponectin to induce insulin resistance in maternal and fetal tissues. Increased concentrations of tumor necrosis factor-alpha and interleukin-6 enhance expression and activity of 11beta-hydroxysteroid dehydrogenase type 1 enzyme, which produces abdominal obesity, insulin resistance, hyperlipidemia, hyperphagia, and hyperleptinemia, characteristic features of metabolic syndrome X. Continued consumption of an energy-dense diet in childhood aggravates these molecular events. This implies that supplementation of long-chain polyunsaturated fatty acids (especially AA, EPA, and DHA in appropriate ratios) from the perinatal period through adulthood could prevent, arrest, or postpone development of metabolic syndrome X.
Das, U. N. (2005). "COX-2 inhibitors and metabolism of essential fatty acids." Med Sci Monit 11(7): RA233-7. Selective COX-2 inhibitors increase the risk of myocardial infarction and stroke that is attributed to their ability to inhibit prostacyclin (PGI2), lipoxins, resolvins, and endothelial nitric oxide (eNO) but not platelet COX-1 derived thromboxane A2 (TXA2). In contrast, aspirin blocks both COX-1 and COX-2 enzymes that, in turn, increases intracellular concentrations of dihomo-gamma-linolenic acid (DGLA), arachidonic acid (AA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) and reduced formation of eicosanoids. On the other hand, such an increase is much less with specific COX-2 inhibitors since they do not block the formation of eicosanoids through COX-1 pathway. DGLA, AA and EPA form precursors to PGE1, PGI2, and PGI3 respectively, which are potent vasodilators and platelet anti-aggregators, and thus aid in the prevention of thrombus formation. EPA has anti-arrhythmic action, and EPA, DHA (docosahexaenoic acid), DGLA, and PGE1 have anti-inflammatory actions as well. EPA, DHA, and AA augment eNO formation that has anti-atherosclerotic action. Hence, combining EFAs with COX-2 inhibitors will prevent thrombotic cardiovascular events.
Das, U. N. (2005). "Can COX-2 inhibitor-induced increase in cardiovascular disease risk be modified by essential fatty acids?" J Assoc Physicians India 53: 623-7. Selective COX-2 inhibitors increase the risk of myocardial infarction and stroke. This has been attributed to their ability to inhibit endothelial COX-2 derived prostacyclin (PGI2) but not platelet COX-1 derived thromboxane A2 (TXA2). On the other hand, aspirin blocks both COX-1 and COX-2 enzymes without decreasing PGI2 but blocks TXA2 synthesis that explains its beneficial action in the prevention of coronary heart disease (CHD). The inhibitory action of aspirin on COX-1 and COX-2 enzymes enhances the tissue concentrations of dihomo-gamma-linolenic acid (DGLA), arachidonic acid, eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA). These fatty acids form precursors to PGE1, PGI2, PGI3, lipoxins (LXs), and resolvins that have anti-inflammatory actions. In contrast, increase in the concentrations of DGLA, AA, EPA, and DHA is much less with specific COX-2 inhibitors since they do not block the formation of eicosanoids through COX-1 pathway. COX-2 inhibitors interfere with the formation of LXs and resolvins that have neuroprotective and cardioprotective actions. EPA and PGI2 have anti-arrhythmic action. EPA, DHA, and AA augment eNO formation that prevents atherosclerosis. This suggests that COX-2 inhibitors increase cardiovascular and stroke risk by interfering with the formation of eNO, PGI2, LXs, and resolvins and implies that combining EFAs with COX-2 inhibitors could prevent these complications.
Cole, G. M., G. P. Lim, et al. (2005). "Prevention of Alzheimer's disease: Omega-3 fatty acid and phenolic anti-oxidant interventions." Neurobiol Aging 26 Suppl 1: 133-6. Alzheimer's disease (AD) and cardiovascular disease (CVD) are syndromes of aging that share analogous lesions and risk factors, involving lipoproteins, oxidative damage and inflammation. Unlike in CVD, in AD, sensitive biomarkers are unknown, and high-risk groups are understudied. To identify potential prevention strategies in AD, we have focused on pre-clinical models (transgenic and amyloid infusion models), testing dietary/lifestyle factors strongly implicated in reducing risk in epidemiological studies. Initially, we reported the impact of non-steroidal anti-inflammatory drugs (NSAIDs), notably ibuprofen, which reduced amyloid accumulation, but suppressed few inflammatory markers and without reducing oxidative damage. Safety concerns with chronic NSAIDs led to a screen of alternative NSAIDs and identification of the phenolic anti-inflammatory/anti-oxidant compound curcumin, the yellow pigment in turmeric that we found targeted multiple AD pathogenic cascades. The dietary omega-3 fatty acid, docosahexaenoic acid (DHA), also limited amyloid, oxidative damage and synaptic and cognitive deficits in a transgenic mouse model. Both DHA and curcumin have favorable safety profiles, epidemiology and efficacy, and may exert general anti-aging benefits (anti-cancer and cardioprotective.).
Chen, C. and N. G. Bazan (2005). "Lipid signaling: sleep, synaptic plasticity, and neuroprotection." Prostaglandins Other Lipid Mediat 77(1-4): 65-76. Increasing evidence indicates that bioactive lipids participate in the regulation of synaptic function and dysfunction. We have demonstrated that signaling mediated by platelet-activating factor (PAF) and cyclooxygenase (COX)-2-synthesized PGE2 is involved in synaptic plasticity, memory, and neuronal protection [Clark GD, Happel LT, Zorumski CF, Bazan NG. Enhancement of hippocampal excitatory synaptic transmission by platelet-activating factor. Neuron 1992; 9:1211; Kato K, Clark GD, Bazan NG, Zorumski CF. Platelet-activating factor as a potential retrograde messenger in CA1 hippocampal long-term potentiation. Nature 1994; 367:175; Izquierdo I, Fin C, Schmitz PK, et al. Memory enhancement by intrahippocampal, intraamygdala or intraentorhinal infusion of platelet-activating factor measured in an inhibitory avoidance. Proc Natl Acad Sci USA 1995; 92:5047; Chen C, Magee CJ, Bazan NG. Cyclooxygenase-2 regulates prostaglandin E2 signaling in hippocampal long-term synaptic plasticity. J Neurophysiol 2002; 87:2851]. Recently, we found that prolonged continuous wakefulness (primarily rapid eye movement (REM)-sleep deprivation, SD) causes impairments in hippocampal long-term synaptic plasticity and hippocampus-dependent memory formation [McDermott CM, LaHoste GJ, Chen C, Musto A, Bazan NG, Magee JC. Sleep deprivation causes behavioral, synaptic, and membrane excitability alterations in hippocampal neurons. J Neurosci 2003; 23:9687]. To explore the mechanisms underlying SD-induced impairments, we have studied several bioactive lipids in the hippocampus following SD. It appears that SD causes increases in prostaglandin D2 (PGD2) and 2-arachidonylglycerol (2-AG), and a decrease in PGE2, suggesting that these lipid messengers participate in memory consolidation during REM sleep. We have also explored the formation of endogenous neuroprotective lipids. Toward this aim, we have used ischemia-reperfusion damage and LC-PDA-ESI-MS-MS-based lipidomic analysis and identified docosanoids derived from synaptic phospholipid-enriched docosahexaenoic acid. Some of the docosanoids exert potent neuroprotective bioactivity [Marcheselli VL, Hong S, Lukiw WJ, et al. Novel docosanoids inhibit brain ischemia-reperfusion-mediated leukocyte infiltration and pro-inflammatory gene expression. J Biol Chem 2003; 278:43807; Mukherjee PK, Marcheselli VL, Serhan CN, Bazan, NG. Neuroprotectin D1: A docosahexaenoic acid-derived docosatriene protects human retinal pigment epithelial cells from oxidative stress. Proc Nat Acad Sci USA 2004; 101:8491). Taken together, these observations that signaling lipids participate in synaptic plasticity, cognition, and survival indicate that lipid signaling is closely associated with several functions (e.g; learning and memory, sleep, and experimental stroke) and pathologic events. Alterations in endogenous signaling lipids or their receptors resulting from drug abuse lead to changes in synaptic circuitry and induce profound effects on these important functions. In the present article, we will briefly review bioactive lipids involved in sleep, synaptic transmission and plasticity, and neuroprotection, focusing mainly on our experimental studies and how these signaling molecules are related to functions and implicated in some neurologic disorders.
Cawood, A. L., M. P. Carroll, et al. (2005). "Is there a case for n-3 fatty acid supplementation in cystic fibrosis?" Curr Opin Clin Nutr Metab Care 8(2): 153-9. PURPOSE OF REVIEW: This review evaluates our current knowledge on the association of fatty acid abnormalities in cystic fibrosis with the disease process, and makes a case for a well-designed clinical trial to evaluate the clinical efficacy of long chain n-3 fatty acids. RECENT FINDINGS: It has long been known that cystic fibrosis patients exhibit fatty acid abnormalities, but these have not been well investigated in tissues affected by the disease. Recent studies have demonstrated that such tissues do indeed show abnormalities in the proportions of linoleic, arachidonic and docosahexaenoic acids, and have demonstrated alterations in fatty acid and phospholipid metabolism in cystic fibrosis. Work in other areas has identified novel anti-inflammatory actions of long chain n-3 fatty acids that might be relevant to cystic fibrosis. A recent systematic review of fish oil supplementation in cystic fibrosis did not allow firm conclusions to be drawn, but suggested that there may be some benefits. SUMMARY: The restoration of abnormal fatty acid profiles may be beneficial in cystic fibrosis, but this approach has not been evaluated in studies with a suitable design to permit firm conclusions to be drawn. There is a need for a long-term randomized controlled study to evaluate the therapeutic benefit of fish oil supplementation in cystic fibrosis.
Calder, P. C. (2005). "Polyunsaturated fatty acids and inflammation." Biochem Soc Trans 33(Pt 2): 423-7. The n-6 polyunsaturated fatty acid, arachidonic acid, is a precursor of prostaglandins, leukotrienes and related compounds that have important roles as mediators and regulators of inflammation. Consuming increased amounts of long chain n-3 polyunsaturated fatty acids (found in oily fish and fish oils) results in a partial replacement of the arachidonic acid in cell membranes by eicosapentaenoic and docosahexaenoic acids. This leads to decreased production of arachidonic acid-derived mediators. This alone is a potentially beneficial anti-inflammatory effect of n-3 fatty acids. However, n-3 fatty acids have a number of other effects that might occur downstream of altered eicosanoid production or are independent of this. For example, they result in suppressed production of pro-inflammatory cytokines and can modulate adhesion molecule expression. These effects occur at the level of altered gene expression.
Burdge, G. C. and P. C. Calder (2005). "Conversion of alpha-linolenic acid to longer-chain polyunsaturated fatty acids in human adults." Reprod Nutr Dev 45(5): 581-97. The principal biological role of alpha-linolenic acid (alphaLNA; 18:3n-3) appears to be as a precursor for the synthesis of longer chain n-3 polyunsaturated fatty acids (PUFA). Increasing alphaLNA intake for a period of weeks to months results in an increase in the proportion of eicosapentaenoic acid (EPA; 20:5n-3) in plasma lipids, in erythrocytes, leukocytes, platelets and in breast milk but there is no increase in docosahexaenoic acid (DHA; 22:6n-3), which may even decline in some pools at high alphaLNA intakes. Stable isotope tracer studies indicate that conversion of alphaLNA to EPA occurs but is limited in men and that further transformation to DHA is very low. The fractional conversion of alphaLNA to the longer chain n-3 PUFA is greater in women which may be due to a regulatory effect of oestrogen. A lower proportion of alphaLNA is used for beta-oxidation in women compared with men. Overall, alphaLNA appears to be a limited source of longer chain n-3 PUFA in humans. Thus, adequate intakes of preformed long chain n-3 PUFA, in particular DHA, may be important for maintaining optimal tissue function. Capacity to up-regulate alphaLNA conversion in women may be important for meeting the demands of the fetus and neonate for DHA.
Birch, D. G. (2005). "A randomized placebo-controlled clinical trial of docosahexaenoic acid (DHA) supplementation for X-linked retinitis pigmentosa." Retina 25(8 Suppl): S52-S54.
Bazan, H. E. (2005). "Cellular and molecular events in corneal wound healing: significance of lipid signalling." Exp Eye Res 80(4): 453-63. Alterations in the normal healing process after corneal injury can produce undesirable outcomes that range from corneal haze to ulceration and perforation. Lipids play important roles in the complex inflammatory processes that occur after corneal wounding. While some lipid mediators, such as the lipoxygenase derivatives of arachidonic acid, 12-hydroxyeicosatetraenoic acid (12[S]-HETE and 15[S]-HETE), act as second messengers to promote cell proliferation and are possibly involved in the synthesis of other molecules that suppress inflammation, others, such as platelet-activating factor (PAF), exert their actions through specific receptors, play key roles during sustained corneal inflammation (as might occur with chemical burns), and contribute to tissue destruction and neovascularization. PAF is also a strong inducer of selective metalloproteinases (MMPs) that degrade the extracellular matrix. The use of a new PAF antagonist has shown great promise for the treatment of diffuse lamellar keratitis (DLK) and alkali-burned corneas.
Bazan, N. G. (2005). "Neuroprotectin D1 (NPD1): a DHA-derived mediator that protects brain and retina against cell injury-induced oxidative stress." Brain Pathol 15(2): 159-66. The biosynthesis of oxygenated arachidonic acid messengers triggered by cerebral ischemia-reperfusion is preceded by an early and rapid phospholipase A2 activation reflected in free arachidonic and docosahexaenoic acid (DHA) accumulation. These fatty acids are released from membrane phospholipids. Both fatty acids are derived from dietary essential fatty acids; however, only DHA, the omega-3 polyunsaturated fatty acyl chain, is concentrated in phospholipids of various cells of brain and retina. Synaptic membranes and photoreceptors share the highest content of DHA of all cell membranes. DHA is involved in memory formation, excitable membrane function, photoreceptor cell biogenesis and function, and neuronal signaling, and has been implicated in neuroprotection. In addition, this fatty acid is required for retinal pigment epithelium cell (RPE) functional integrity. Here we provide an overview of the recent elucidation of a specific mediator generated from DHA that contributes at least in part to its biological significance. In oxidative stress-challenged human RPE cells and rat brain undergoing ischemia-reperfusion, 10,17S-docosatriene (neuroprotectin D1, NPD1) synthesis evolves. In addition, calcium ionophore A23187, IL-1beta, or the supply of DHA enhances NPD1 synthesis. A time-dependent release of endogenous free DHA followed by NPD1 formation occurs, suggesting that a phospholipase A2 releases the mediator's precursor. When NPD1 is infused during ischemia-reperfusion or added to RPE cells during oxidative stress, apoptotic DNA damage is down-regulated. NPD1 also up-regulates the anti-apoptotic Bcl-2 proteins Bcl-2 and BclxL and decreases pro-apoptotic Bax and Bad expression. Moreover, NPD1 inhibits oxidative stress-induced caspase-3 activation. NPD1 also inhibits IL-1beta-stimulated expression of COX-2. Overall, NPD1 protects cells from oxidative stress-induced apoptosis. Because photoreceptors are progressively impaired after RPE cell damage in retinal degenerative diseases, understanding of how these signals contribute to retinal cell survival may lead to the development of new therapeutic strategies. Moreover, NPD1 bioactivity demonstrates that DHA is not only a target of lipid peroxidation, but rather is the precursor to a neuroprotective signaling response to ischemia-reperfusion, thus opening newer avenues of therapeutic exploration in stroke, neurotrauma, spinal cord injury, and neurodegenerative diseases, such as Alzheimer disease, aiming to up-regulate this novel cell-survival signaling.
Bazan, N. G. (2005). "Synaptic signaling by lipids in the life and death of neurons." Mol Neurobiol 31(1-3): 219-30. Synaptic activity promotes the regulated formation of lipid messengers through phospholipase-mediated cleavage of specific phospholipid reservoirs from membranes. Multiple effectors trigger the formation of lipid messengers, including neurotransmitters, membrane depolarization, ion channels, cytokines, and neurotrophic factors. Lipid messengers in turn modulate and interact with other signaling cascades, contributing to the development, differentiation, function (e.g., long-term potentiation [LTP] and memory), protection, and repair of cells in the nervous system. These relationships with other signaling cascades remain largely to be investigated. Oxidative stress disrupts lipid signaling, enhances lipid peroxidation, and initiates and propagates neurodegeneration. There is growing evidence that lipid messengers participate in the extensive interactions among neurons, astrocytes, oligodendrocytes, microglia, cells of the microvasculature, and other cells. This article provides an example of how signaling by lipids regulates critical events essential for neuronal survival and reviews the recent identification of a novel endogenous neuroprotective signaling pathway involving a docosahexaenoic acid-derived mediator.
Bazan, N. G. (2005). "Lipid signaling in neural plasticity, brain repair, and neuroprotection." Mol Neurobiol 32(1): 89-103. The extensive networking of the cells of the nervous system results in large cell membrane surface areas. We now know that neuronal membranes contain phospholipid pools that are the reservoirs for the synthesis of specific lipid messengers on neuronal stimulation or injury. These messengers in turn participate in signaling cascades that can either promote neuronal injury or neuroprotection. Prostaglandins are synthesized as a result of cyclooxygenase activity. In the first step of the arachidonic acid cascade, the short-lived precursor, prostaglandin H2, is synthesized. Additional steps in the cascade result in the synthesis of an array of prostaglandins, which participate in numerous physiological and neurological processes. Our laboratory recently reported that the membrane polyunsaturated fatty acid, docosahexaenoic acid, is the precursor of oxygenation products now known as the docosanoids, some of which are powerful counter-proinflammatory mediators. The mediator 10,17S-docosatriene (neuroprotectin D1, NPD1) counteracts leukocyte infiltration, NF-kappa activation, and proinflammatory gene expression in brain ischemia-reperfusion and is an apoptostatic mediator, potently counteracting oxidative stress-triggered apoptotic DNA damage in retinal pigment epithelial cells. NPD1 also upregulates the anti-apoptotic proteins Bcl-2 and Bcl-xL and decreases pro-apoptotic Bax and Bad expression. Another biologically active messenger derived from membrane phospholipids in response to synaptic activity is platelet-activating factor (PAF). The tight regulation of the balance between synthesis (via phospholipases) and degradation (via acetylhydrolases) of PAF modulates the functions of this lipid messenger. Under pathological conditions, this balance is tipped, and PAF becomes a proinflammatory mediator and neurotoxic agent. The newly discovered docosahexaenoic acid signaling pathways, as well as other lipid messengers related to synaptic activation, may lead to the clarification of clinical issues relevant to stroke, age-related macular degeneration, spinal cord injury, Alzheimer's disease, and other diseases that include neuroinflammatory components.
Bazan, N. G., V. L. Marcheselli, et al. (2005). "Brain response to injury and neurodegeneration: endogenous neuroprotective signaling." Ann N Y Acad Sci 1053: 137-47. Synaptic activity and ischemia/injury promote lipid messenger formation through phospholipase-mediated cleavage of specific phospholipids from membrane reservoirs. Lipid messengers modulate signaling cascades, contributing to development, differentiation, function (e.g., memory), protection, regeneration, and repair of neurons and overall regulation of neuronal, glial, and endothelial cell functional integrity. Oxidative stress disrupts lipid signaling and promotes lipid peroxidation and neurodegeneration. Lipid signaling at the neurovascular unit (neurons, astrocytes, oligodendrocytes, microglia, and cells of the microvasculature) is altered in early cerebrovascular and neurodegenerative disease. We discuss how lipid signaling regulates critical events in neuronal survival. Aberrant synaptic plasticity (e.g., epileptogenesis) is highlighted to show how gene expression may drive synaptic circuitry formation in the "wrong" direction. Docosahexaenoic acid has been implicated in memory, photoreceptor cell biogenesis and function, and neuroprotection. Free docosahexaenoic acid released in the brain during experimental stroke leads to the synthesis of stereospecific messengers through oxygenation pathways. One messenger, 10,17S-docosatriene (neuroprotectin D1; NPD1), counteracts leukocyte infiltration and proinflammatory gene expression in brain ischemia-reperfusion. In retina, photoreceptor survival depends on retinal pigment epithelial (RPE) cell integrity. NPD1 is synthesized in RPE cells undergoing oxidative stress, potently counteracts oxidative stress-triggered apoptotic DNA damage in RPE, upregulates antiapoptotic proteins Bcl-2 and Bcl-x(L), and decreases proapoptotic Bax and Bad expression. These findings expand our understanding of how the nervous system counteracts redox disturbances, mitochondrial dysfunction, and proinflammatory conditions. The specificity and potency of NPD1 indicate a potential target for therapeutic intervention for stroke, age-related macular degeneration, spinal cord injury, and other neuroinflammatory or neurodegenerative diseases.
Arita, M., C. B. Clish, et al. (2005). "The contributions of aspirin and microbial oxygenase to the biosynthesis of anti-inflammatory resolvins: novel oxygenase products from omega-3 polyunsaturated fatty acids." Biochem Biophys Res Commun 338(1): 149-57. Resolvins (Rvs) are oxygenated products derived from omega-3 polyunsaturated fatty acids (PUFAs) such as eicosapentaenoic acid (EPA) and docosahexaenoic acid that carry potent protective bioactions present in resolving inflammatory exudates. Resolvin E1 (RvE1) is biosynthesized in vivo from EPA via transcellular biosynthetic routes during cell-cell interactions, and thus RvE1 is formed in vivo during multicellular responses such as inflammation and microbial infections. RvE1 protects tissues from leukocyte-mediated injury and counterregulates proinflammatory gene expression. These newly identified Rvs may underlie the beneficial actions of omega-3 PUFAs especially in chronic disorders where unresolved inflammation is a key mechanism of pathogenesis. Here, we present an overview of the biosynthesis of RvE1, with a focus on the aspirin-triggered and microbial P450-initiated pathways. The generation of RvE1 and its actions appear to dampen acute leukocyte responses and facilitate the resolution of inflammation.
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