Acid Composition Of Cell Membranes Research Articles

Fatty acid composition of quail blood erythrocyte membranes under condition of feeding sodium selenite and nanoselenium

Infectious diseases are a significant problem in poultry farming, because they significantly slow down the growth rate of the industry and lead to losses. For the productive development of the industry and the avoidance of danger to the health of consumers due to the uncontrolled use of these drugs, it is worth using alternative methods of protecting poultry and improving the quality of the obtained products, in particular drugs obtained by nanotechnological means. Nowadays, nanoparticles of various minerals are used in poultry farming, the mineral antagonism of which is reduced in the intestines, compared to preparations of the usual size, which contributes to the modulation of absorption mechanisms, optimization of the immune response, and increased efficiency of digestion. Oxidative stress is a harmful factor for cellular integrity due to the constant release of reactive forms of oxygen. Se is widely used as a supplement to reduce oxidative stress. The element is found in organic and inorganic compounds, replaces Sulfur in protein molecules and is an important part of selenoproteins. Se is known for its antioxidant activity, plays a major role in optimizing redox potential, reproductive processes, hormone metabolism, muscle development, and anticarcinogenesis. Nano-Se results in higher Se retention activity due to smaller size and greater bioavailability. Biogenic selenium nanoparticles (SeNPs), synthesized with the participation of bacteria, have unique physicochemical and biological properties compared to inorganic and organic compounds, and nanoselenium-enriched probiotic bacteria can be effectively used as an alternative to other forms of selenium as food and feed additives. The work compared the composition of fatty acids of lipids extracted from erythrocytes of quail blood, which were injected with sodium selenite and pro-oxidant nano-Se. With the introduction of nanoselenium, a decrease in the level of NFAs was noted, as well as a significant increase in the level of the main PUFAs. The lack of compensatory accumulation of docosapolyene fatty acids in the cell membranes of erythrocytes of birds of the 2nd group can be considered as a factor of the beneficial effect of the administered drug, as well as as a justification for the need to prescribe complex drugs to birds capable of modulating the fatty acid composition of cell membranes. The effectiveness of using a complex nanopreparation consists in normalizing the level of fatty acids and restoring their metabolism at the stage of eicosanoid formation. Key words: fatty acids, quails, peroxide oxidation, selenium, sodium selenite, nanoselenium, nanoparticles, lipids.

Features of the metabolism of polyunsaturated fatty acids in type 2 diabetes mellitus

Type 2 diabetes mellitus (T2DM) is a widespread disease with a high risk of cardiovascular complications, disability and mortality. The progression of T2DM is closely related to lipid metabolism disorders, caused both by insufficient intake of polyunsaturated fatty acids (PUFAs), and by a violation of their endogenous metabolism. Desaturase enzymes, FADS1/2, are involved in the regulation of PUFA metabolism. Violation of the functioning of FADS1/2 and their genes leads to a change in the biosynthesis of PUFAs and the fatty acid composition of cell membranes. The purpose of this research was to summarize the data of modern literature on the metabolism of PUFAs and the effect of FADS genetic variants on the fatty acid composition of cell membranes in T2DM. Material and methods. The search and analysis of publications was carried out using the PubMed, MEDLINE, Web of Science databases, mainly for the last 10 years, using the search keywords: polyunsaturated fatty acids, fatty acid desaturases, desaturase genes, type 2 diabetes mellitus. Results. In the pathogenesis of T2DM and its complications, many factors play a role, including impaired PUFA metabolism. A large evidence base has been accumulated on the effect of PUFAs on cardiometabolic risk factors in T2DM. The effect of desaturase activity on the fatty acid composition of cells was identified as the most important link in the metabolism of PUFAs. Focusing on the modulation of desaturase activity and studying the polymorphism of fatty acid desaturase genes may be a useful therapeutic option in the treatment of patients with T2DM and its complications. Conclusion. A promising direction of scientific research in the treatment and prevention of T2DM and its complications is the study of genetic mechanisms associated with the metabolism of PUFAs and their metabolites.

Ferroptosis Regulation by Nutrient Signalling.

Tremendous progress has been made in the field of ferroptosis since this regulated cell death process was first named in 2012. Ferroptosis is initiated upon redox imbalance and driven by excessive phospholipid peroxidation. Levels of multiple intracellular nutrients (iron, selenium, vitamin E and coenzyme Q10) are intimately related to the cellular antioxidant system and participate in the regulation of ferroptosis. Dietary intake of monounsaturated fatty acids (MUFA) and polyunsaturated fatty acids (PUFA) regulates ferroptosis by directly modifying the fatty acid composition in cell membranes. In addition, amino acids and glucose (energy stress) manipulate the ferroptosis pathway through the nutrient-sensitive kinases mechanistic target of rapamycin complex 1 (mTORC1) and AMP-activated protein kinase (AMPK). Understanding the molecular interaction between nutrient signals and ferroptosis sensors might help in the identification of the roles of ferroptosis in normal physiology and in the development of novel pharmacological targets for the treatment of ferroptosis-related diseases.

Towards industrial production of microalgae without temperature control: The effect of diel temperature fluctuations on microalgal physiology

Regions that offer high levels of sunlight are ideal to produce microalgae. However, as a result of high light intensities, the temperature in photobioreactors can reach temperatures up to 50 °C. Control of temperature is essential to avoid losses on biomass productivity but should be limited to a minimum to avoid high energy requirements for cooling. Our objective is to develop a production process in which cooling is not required. We studied the behaviour of thermotolerant microalgae Picochlorum sp. (BPE23) under four diel temperature regimes, with peak temperatures from 30 °C up to a maximum of 47.5 °C. The highest growth rate of 0.17 h−1 was obtained when applying a daytime peak temperature of 40 °C. Operating photobioreactors in tropical regions, with a maximal peak temperature of 40 °C, up from 30 °C, reduces microalgae production costs by 26.2 %, based on simulations with a pre-existing techno-economic model. Cell pigmentation was downregulated under increasingly stressful temperatures. The fatty acid composition of cell membranes was altered under increasing temperatures to contain shorter fatty acids with a higher level of saturation. Our findings show that the level of temperature control impacts the biomass yield and composition of the microalgae.

Preharvest or a combination of preharvest and postharvest treatments with methyl jasmonate reduced chilling injury, by maintaining higher unsaturated fatty acids, and increased aril colour and phenolics content in pomegranate

Abstract In the present research the effects of preharvest 5 mM methyl jasmonate (MeJa) treatments, alone (Pre) or in combination with postharvest 5 mM MeJa treatment (Pre + Post), on reducing chilling injury (CI) of pomegranate during 90 d of storage at 2 °C plus 3 d at 20 °C and its relationship with changes in fatty acid composition of cell membranes were assayed. In addition, fruit and aril quality traits, total content in phenolics and anthocyanins and antioxidant activity of the arils were evaluated. Both, external and internal CI symptoms and the increase in ion leakage (IL) were reduced by Pre and Pre + Post MeJa treatments. The major fatty acids in pomegranate husk were palmitic, oleic, linoleic and linolenic acids. MeJa treatments led to higher concentration of unsaturated fatty acids (UFA) at harvest, which wasmaintained at higher levels during storage, while saturated fatty acid (SFA) concentration was lower in treated fruit than in controls. The concentration of total phenolics and anthocyanins were lower in the arils from control fruit than in arils of Pre and Pre + Post treated fruit during the whole storage period. In general, there were no significant differences between Pre and Pre + Post MeJa treatments on their effects on reducing CI, maintaining membrane stability and bioactive compounds with antioxidant activity. Thus, preharvest MeJa treatments may be sufficient to increase the cold storage potential of pomegranate fruit by reducing CI symptoms and enhancing the content bioactive compounds with antioxidant activity.

Genes and Dietary Fatty Acids in Regulation of Fatty Acid Composition of Plasma and Erythrocyte Membranes.

The fatty acid compositions of plasma lipids and cell membranes of certain tissues are modified by dietary fatty acid composition. Furthermore, many other factors (age, sex, ethnicity, health status, genes, and gene × diet interactions) affect the fatty acid composition of cell membranes or plasma lipid compartments. Therefore, it is of great importance to understand the complexity of mechanisms that may modify fatty acid compositions of plasma or tissues. We carried out an extensive literature survey of gene × diet interaction in the regulation of fatty acid compositions. Most of the related studies have been observational studies, but there are also a few intervention trials that tend to confirm that true interactions exist. Most of the studies deal with the desaturase enzyme cluster (FADS1, FADS2) in chromosome 11 and elongase enzymes. We expect that new genetic variants are being found that are linked with the genetic regulation of plasma or tissue fatty acid composition. This information is of great help to understanding the contribution of dietary fatty acids and their endogenic metabolism to the development of some chronic diseases.

Combined effects of temperature and metal exposure on the fatty acid composition of cell membranes, antioxidant enzyme activities and lipid peroxidation in yellow perch (Perca flavescens)

The aim of this study was to investigate the combined effects of temperature and metal contamination (cadmium and nickel) on phospholipid fatty acid composition, antioxidant enzyme activities and lipid peroxidation in fish. Yellow perch were acclimated to two different temperatures (9°C and 28°C) and exposed either to Cd or Ni (respectively 4μg/L and 600μg/L) for seven weeks. Superoxide dismutase, catalase, glutathione-S-transferase, glutathione peroxidase activities and glutathione concentration were measured as indicators of antioxidant capacities, while malondialdehyde concentration was used as an indicator of lipid peroxidation. Poikilotherms including fish counteract the effects of temperature on phospholipid fatty acid ordering by remodelling their composition to maintain optimal fluidity. Accordingly, in our study, the fatty acid composition of yellow perch muscle at 9°C was enhanced in monounsaturated (MUFA) and polyunsaturated fatty acids (PUFA) compared to fish maintained at 28°C, in agreement with the theory of homeoviscous adaptation. Using ratios of various fatty acids as surrogates for desaturase and elongase activities, our data suggests that modification of the activity of these enzymes is responsible for the thermal acclimation of phospholipid fatty acid profiles. However, this response was altered under Ni and Cd exposure: PUFA decreased (specifically n-6 PUFA) while the proportion of saturated fatty acids increased at 9°C, whereas at 28°C, PUFA increased to proportions exceeding those observed at 9°C. Lipid peroxidation could be observed under all experimental conditions. Both enzymatic and non-enzymatic antioxidant defense systems acted cooperatively to cope with oxidative stress leading to lipid peroxidation, which was not affected by temperature acclimation as indicated by malondialdehyde concentration, in spite of a higher polyinsaturation in cold-acclimated fish which would be predicted to increase their vulnerability to peroxidation. However, in warm-acclimated, Ni-exposed fish, in which the highest proportion of PUFA was observed, lower concentrations of malondialdehyde were measured, suggesting an overcompensation of antioxidant mechanisms in these fish which could represent a substantial metabolic cost and explain their lower condition.

System-level understanding of the potential acid-tolerance components of Acidithiobacillus thiooxidans ZJJN-3 under extreme acid stress.

In previous study, two extremely acidophilic strains Acidithiobacillus thiooxidans ZJJN-3 (collection site: bioleaching leachate) and ZJJN-5 (collection site: bioleaching wastewater) were isolated from a typical industrial bio-heap in China. Here, we unraveled the potential acid-tolerance components of ZJJN-3 by comparing the physiological differences with ZJJN-5 under different acid stresses. The parameters used for comparison included intracellular pH (pHin), capsule morphology, fatty acid composition of cell membrane, transcription of key molecular chaperones, H(+)-ATPase activities and NAD(+)/NADH ratio. It was indicated that the acid-tolerance of A. thiooxidans ZJJN-3 was systematically regulated. Capsule first thickened and then shed off along with increased acid stress. Cell membrane maintained the intracellular stability by up-regulating the proportion of unsaturated fatty acid and cyclopropane fatty acids. Meanwhile, the transcription of key repair molecular chaperones (GrpE-DnaK-DnaJ) was up-regulated by 2.2-3.5 folds for ensuring the proper folding of peptide. Moreover, low pHin promoted ZJJN-3 to biosynthesize more H(+)-ATPase for pumping H(+) out of cells. Furthermore, the NAD(+)/NADH ratio increased due to the decreased H(+) concentration. Based on the above physiological analysis, the potential acid-tolerance components of A. thiooxidans ZJJN-3 were first proposed and it would be useful for better understanding how these extremophiles responded to the high acid stress.

Evaluation of Antioxidant Potential of Clarias Batrachus Oil in Alloxan Induced Diabetic Mice (Mus Musculus)

Introduction: Diabetes mellitus is a chronic disorder in human and responsible for different complications and also causes mortality and morbidity. Long chain fatty acids influence inflammation through a variety of mechanisms; many of these are mediated by, or at least associated with, changes in fatty acid composition of cell membranes. Hence the present study was performed to investigate the effect of fish oil extracted from Clarias batrachus which is a good source of PUFA n-3 among freshwater species on alloxan-induced diabetic mice. Material and method: Alloxan was administered at repetitive doses (100 mg/kg b.wt after every 5th day for a period of one month to induce diabetes in mice. Along with alloxan injection, 10% Clarias fish oil was supplemented to diabetic mice for a period of one month. Analysis of basic antioxidant and lipid peroxidation parameters in serum, liver, kidney, heart and pancreatic tissues was carried out. Result: The levels of antioxidant and lipid peroxidation markers were significantly (P<0.05) altered in all the tissues of alloxan-induced diabetic mice. The supplementation of fish oil to diabetic mice showed significant recovery in activity of enzymes SOD, Catalase and in concentration of Vitamin C which is decreased in diabetic control mice. Conclusion: The result of this study indicated fish oil supplementation in diabetic mice helped to reduce the elevated glucose and glycosylated haemoglobin level along with an increase in insulin concentration and helped to recover the altered antioxidant and enzyme activity, which specifies that long term treatment of diabetes with fish oil may help to reduce the diabetes induced tissue damages.

Docosahexaenoic acid attenuates oxidative stress and protects human gingival fibroblasts against cytotoxicity induced by hydrogen peroxide and butyric acid

ObjectiveThe oxidative burst of the host cells associated with bacterial pathogen infection contributes to the destruction of periodontal tissue. The present study investigates the effect of docosahexaenoic acid (DHA) on human gingival fibroblast (HGF) viability and ROS generation. MethodsThe cell viability by MTT assay, ROS level using H2DCF-DA probe, and protein thiol content were measured in HGFs after 24h preincubation with different concentrations of DHA followed by treatment with H2O2. The cell death rate was determined by Annexin V/propidium iodide staining, and mitochondrial membrane potential (ΔΨm) was examined by MitoTracker Red probe in H2O2- and butyric acid-treated HGFs. The fatty acid composition of plasma membranes after incubation with DHA was determined by gas chromatography mass spectrometry. ResultsDHA preincubation in a dose-dependent manner increased the viability of HGFs exposed to H2O2 and decreased ROS generation compared to the control cells. In HGFs preincubated with 30μM DHA, the ΔΨm significantly increased in both H2O2- and butyric acid-treated cells. Moreover, incubation with DHA preserved the protein thiol level as effectively as N-acetylcysteine. Application of 50μM DHA increased the quantity of viable cells, decreased the number of necrotic cells after H2O2 treatment, and protected HGFs from apoptosis induced by butyric acid. DHA in the plasma membranes of these HGFs represented about 6% of the total amount of fatty acids. ConclusionsThese results demonstrate that enrichment of HGFs with DHA reduces ROS generation and enhances the mitochondrial membrane potential protecting the fibroblasts against cytotoxic factors.

Atherosclerosis, dyslipidemia, and inflammation: the significant role of polyunsaturated Fatty acids.

Phospholipids play an essential role in cell membrane structure and function. The length and number of double bonds of fatty acids in membrane phospholipids are main determinants of fluidity, transport systems, activity of membrane-bound enzymes, and susceptibility to lipid peroxidation. The fatty acid profile of serum lipids, especially the phospholipids, reflects the fatty acid composition of cell membranes. Moreover, long-chain n-3 polyunsatured fatty acids decrease very-low-density lipoprotein assembly and secretion reducing triacylglycerol production. N-6 and n-3 polyunsatured fatty acids are the precursors of signalling molecules, termed “eicosanoids,” which play an important role in the regulation of inflammation. Eicosanoids derived from n-6 polyunsatured fatty acids have proinflammatory actions, while eicosanoids derived from n-3 polyunsatured fatty acids have anti-inflammatory ones. Previous studies showed that inflammation contributes to both the onset and progression of atherosclerosis: actually, atherosclerosis is predominantly a chronic low-grade inflammatory disease of the vessel wall. Several studies suggested the relationship between long-chain n-3 polyunsaturated fatty acids and inflammation, showing that fatty acids may decrease endothelial activation and affect eicosanoid metabolism.

The role of marine omega‐3 (n‐3) fatty acids in inflammatory processes, atherosclerosis and plaque stability

Atherosclerosis has an important inflammatory component and acute cardiovascular events can be initiated by inflammatory processes occurring in advanced plaques. Fatty acids influence inflammation through a variety of mechanisms; many of these are mediated by, or associated with, the fatty acid composition of cell membranes. Human inflammatory cells are typically rich in the n-6 fatty acid arachidonic acid, but the contents of arachidonic acid and of the marine n-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) can be altered through oral administration of EPA and DHA. Eicosanoids produced from arachidonic acid have roles in inflammation. EPA also gives rise to eicosanoids and these are usually biologically weak. EPA and DHA give rise to resolvins which are anti-inflammatory and inflammation resolving. EPA and DHA also affect production of peptide mediators of inflammation (adhesion molecules, cytokines, etc.). Thus, the fatty acid composition of human inflammatory cells influences their function; the contents of arachidonic acid, EPA and DHA appear to be especially important. The anti-inflammatory effects of marine n-3 polyunsaturated fatty acids (PUFAs) may contribute to their protective actions towards atherosclerosis and plaque rupture.

Lipid Composition of Cell Membranes and Its Relevance in Type 2 Diabetes Mellitus

Identifying the causative relationship between the fatty acid composition of cell membranes and type 2 diabetes mellitus fundamentally contributes to the understanding of the basic pathophysiological mechanisms of the disease. Important outcomes of the reviewed studies appear to support the hypotheses that the flexibility of a membrane determined by the ratio of (poly)unsaturated to saturated fatty acyl chains of its phospholipids influences the effectiveness of glucose transport by insulin-independent glucose transporters (GLUTs) and the insulin-dependent GLUT4, and from the prediabetic stage on a shift from unsaturated towards saturated fatty acyl chains of membrane phospholipids directly induces a decrease in glucose effectiveness and insulin sensitivity. In addition, it has become evident that a concomitant increase in stiffness of both plasma and erythrocyte membranes may decrease the microcirculatory flow, leading ultimately to tissue hypoxia, insufficient tissue nutrition, and diabetes-specific microvascular pathology. As to the etiology of type 2 diabetes mellitus, a revised hypothesis that attempts to accommodate the reviewed findings is presented.

Вплив омега-3 поліненасичених жирних кислот на дихання та набухання мітохондрій серця при експериментальному цукровому діабеті

We studied the influence of omega-3 polyunsaturated fatty acids (PUFAs) on respiration, swelling of rat heart mitochondria and changes in rat heart fatty acid composition in tissue homogenate in rats with streptozotocin induced diabetes mellitus (diabetes), which was induced by single intraperitoneal administration of 55 mg/kg streptozotocin. We found that application of these acids increased parameters of active mitochondrial respiration V3 at 63.7%, controlled breathing V4 at 30.7% and the rate of phosphorylation by 18.9% in animals with experimental diabetes. We proved their ability to reduce swelling of mitochondria in heart at streptozotocin induced diabetes. In addition, we established changes of fatty acid composition of cell membranes in hearts under diabetic conditions with omega-3 PUFAs influence. The obtained results allow to conclude that the omega-3 PUFA have a positive effect on functional parameters of mitochondria due to stabilization cell membranes of rat heart with diabetes.

Papel dos ácidos graxos ômega 3 na resolução dos processos inflamatórios

A inflamação é uma resposta de defesa do organismo ao trauma ou a infecções por microorganismos.Na fase de término da inflamação e retorno à homeostase ocorrem mecanismos de regulação chamados de resolução onde há alternância de prostaglandinas pró-inflamatórias e leucotrienos a mediadores pró-resolução, produzidos a partir de ácidos graxos poliinsaturados ω3 (ácido eicosapentanóico eácido docosapentanóico). A dieta interfere na composição de ácidos graxos das membranas celularesque serão metabolizados em compostos ativos chamados de resolvinas, protectinas e maresinas.Como as doenças inflamatórias têm papel importante na saúde pública o estudo destas substâncias eo delineamento de seus efeitos podem trazer novos horizontes no tratamento das doenças inflamató-rias, com redução de custos e minimização de efeitos colaterais.

Changes in the fatty acid composition of blood cell membranes in children with inflammatory diseases

Fatty acid composition of erythrocyte and leukocyte membranes has been studied in children (with normal body mass and obesity) with inflammatory diseases of the gastrointestinal tract and children with bronchial asthma in comparison with basically healthy children. Fifty seven children aged from 7 to 14 years were examined: 13 with inflammatory diseases of the gastrointestinal tract (IDGIT) (eosophagitis, gastroduodenitis, stomach ulcer), 25 with obesity stages (I-III) complicated by IDGIT, 9 with bronchial asthma and 10 basically healthy children. The study revealed that both IDGIT and bronchial asthma caused significant and similar changes in fatty acid composition of cell membranes. These included accumulation of omega3-eicosapentaenoic acid (EPA) and the decrease of docosahexaenoic acid (DHA); this phenomenon observed in both erythrocyte and leukocyte membranes suggests a common feature of the detected changes in fatty acid composition of cell membranes in inflammation. There was a significant decrease in the level of membrane omega6 polyunsaturated fatty acids (PUFA), first of all arachidonic acid and total omega6 PUFA. Consequently, EPA accumulation in membranes may be a compensatory response to low dietary arachidonic acid supply and/or its increased synthesis of pro-inflammatory eicosanoids (prostaglandins, leukotriens, thromboxans) during inflammatory process.

Effect of themicrobial lipopeptide on tumor cell lines: apoptosis induced by disturbing the fatty acid composition of cell membrane

Microbial lipopeptides play an important role in apoptosis induction of tumor cells. However, there is little knowledge about the relationship between apoptosis induction and membrane fatty acids. The present study focused on the effects of lipopeptides produced by Bacillus subtilis HSO121 on Bcap-37 cell lines. 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl (MTT) colorimetric assay and surface tension measurements, showed that the critical micelle concentration (CMC) was a critical level for the inhibitory activity of lipopeptides on the growth of Bcap-37 cells. Under the CMC, the order of least to greatest cytotoxicity effect on cancer cell lines by lipopeptides is C(13)-lipopeptide < C(14)-lipopepitde < C(15)-lipopeptide. Above CMC, all lipopeptides directly exert cytolytic activity. The flow cytometric analysis and Hoechst33258 staining experiments confirmed the apoptosis of Bcap-37 cell lines induced by lipopeptides in a dose-dependent manner. This apoptosis was associated with a significant decrease of the unsaturated degree of the cellular fatty acids of Bcap-37 cell lines due to the changes in the cellular fatty acids composition induced by the lipopeptide treatment. These results indicated that disturbance of the cellular fatty acid composition of breast cancer cell lines were related to in the cell apoptosis. Furthermore, significant difference in IC(50) values of tumor cells and normal cell showed that the lipopeptide exerted selective cytotoxicity on the cancer cells. Thus HSO121 lipopeptides may have potential applications as an anticancer leads.

Effects of the ω‐6:ω‐3 Fatty Acid Ratio of Fat Emulsions on the Fatty Acid Composition in Cell Membranes and the Anti‐Inflammatory Action

This study investigated the effects of parenterally administered fish oil (FO) on the fatty acid composition in rats to determine the optimal omega-6:omega-3 polyunsaturated fatty acid (PUFA) ratio of fat emulsions to achieve an anti-inflammatory effect. Male Sprague-Dawley rats were infused a parenteral nutrition (PN) solution containing fat emulsions with different omega-6:omega-3 PUFA ratios. The fatty acid content of phospholipids in the membranes of splenocytes was analyzed by gas chromatography (experiment 1). In addition, the amounts of leukotriene (LT) B(4) and LTB(5) released from peritoneal polymorphonuclear leukocytes (PMNs) were measured by high-performance liquid chromatography (experiment 2). In experiment 1, after infusion of the fat emulsion containing FO, the omega-3 PUFA content in cell membranes rose to 70% of the peak value on day 1 and nearly reached a plateau on day 3. The highest ratio of eicosapentaenoic acid (EPA) to arachidonic acid (AA) was achieved by administering a PN solution with the smallest omega-6:omega-3 PUFA ratio. In experiment 2, a larger amount of LTB(5) was released from Ca-ionophore-stimulated PMNs taken from rats given a larger quantity of FO. The ratio of LTB(5):LTB(4) released from PMNs correlated positively with the EPA:AA ratio in the membranous phospholipid and in serum. The omega-3 PUFAs were readily incorporated into the cell membrane within 3 days of infusion with the fat emulsion. The EPA:AA ratio in membranous phospholipid in PMNs was positively correlated with the LTB(5):LTB(4) production ratio and was a good indicator of anti-inflammatory effects.

Omega-3 Fatty Acids and Inflammatory Processes

Long chain fatty acids influence inflammation through a variety of mechanisms; many of these are mediated by, or at least associated with, changes in fatty acid composition of cell membranes. Changes in these compositions can modify membrane fluidity, cell signaling leading to altered gene expression, and the pattern of lipid mediator production. Cell involved in the inflammatory response are typically rich in the n-6 fatty acid arachidonic acid, but the contents of arachidonic acid and of the n-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) can be altered through oral administration of EPA and DHA. Eicosanoids produced from arachidonic acid have roles in inflammation. EPA also gives rise to eicosanoids and these often have differing properties from those of arachidonic acid-derived eicosanoids. EPA and DHA give rise to newly discovered resolvins which are anti-inflammatory and inflammation resolving. Increased membrane content of EPA and DHA (and decreased arachidonic acid content) results in a changed pattern of production of eicosanoids and resolvins. Changing the fatty acid composition of cells involved in the inflammatory response also affects production of peptide mediators of inflammation (adhesion molecules, cytokines etc.). Thus, the fatty acid composition of cells involved in the inflammatory response influences their function; the contents of arachidonic acid, EPA and DHA appear to be especially important. The anti-inflammatory effects of marine n-3 PUFAs suggest that they may be useful as therapeutic agents in disorders with an inflammatory component.

Life and Death: Metabolic Rate, Membrane Composition, and Life Span of Animals

Maximum life span differences among animal species exceed life span variation achieved by experimental manipulation by orders of magnitude. The differences in the characteristic maximum life span of species was initially proposed to be due to variation in mass-specific rate of metabolism. This is called the rate-of-living theory of aging and lies at the base of the oxidative-stress theory of aging, currently the most generally accepted explanation of aging. However, the rate-of-living theory of aging while helpful is not completely adequate in explaining the maximum life span. Recently, it has been discovered that the fatty acid composition of cell membranes varies systematically between species, and this underlies the variation in their metabolic rate. When combined with the fact that 1) the products of lipid peroxidation are powerful reactive molecular species, and 2) that fatty acids differ dramatically in their susceptibility to peroxidation, membrane fatty acid composition provides a mechanistic explanation of the variation in maximum life span among animal species. When the connection between metabolic rate and life span was first proposed a century ago, it was not known that membrane composition varies between species. Many of the exceptions to the rate-of-living theory appear explicable when the particular membrane fatty acid composition is considered for each case. Here we review the links between metabolic rate and maximum life span of mammals and birds as well as the linking role of membrane fatty acid composition in determining the maximum life span. The more limited information for ectothermic animals and treatments that extend life span (e.g., caloric restriction) are also reviewed.