Associations between red blood cells fatty acids, desaturases indices and metabolism of platelet activating factor in healthy volunteers.

INTRODUCTION: Platelet-activating-factor is an inflammatory lipid mediator. Key enzymes of its biosynthesis are CDP-choline:1-alkyl-2-acetyl-sn-glycerol-cholinephosphotransferase (PAF-CPT) and acetyl-CoA:lyso-PAF-acetyltransferases (Lyso-PAF-AT) while PAF-AH/Lp-PLA2 degrade PAF. The interplay between PAF and fatty acids metabolism was explored. MATERIAL AND METHODS: In a healthy population, PAF levels, its metabolic enzymes activity and RBC fatty acids were measured while desaturases indices (D) were estimated. A principal component analysis was also applied to assess patterns of RBC fatty acids. RESULTS: SFA were related to increased PAF biosynthesis and decreased Lp-PLA2 only in women. MUFA were inversely associated with PAF biosynthesis and positively with Lp-PLA2. Omega-6 fatty acids were positively correlated only with PAF-CPT while no significant correlations were observed with n3 fatty acids. D6 index was positively related with PAF biosynthetic enzymes and inversely with Lp-PLA2 while D9 correlated positively with Lp-PLA2. The pattern of high MUFA and low n6 was associated with reduced PAF biosynthesis and/or increased catabolism in both sexes. CONCLUSION: The role of fatty acids in amplifying or reducing inflammation seems to be also reflected in PAF metabolism.

Mining possible associations of faecal A. muciniphila colonisation patterns with host adiposity and cardiometabolic markers in an adult population.

We aimed to evaluate colonisation patterns of Akkermansia muciniphila in a Greek adult population and to investigate model-adjusted associations of A. muciniphila with host adiposity and cardiometabolic markers. Participants (n=125) underwent anthropometric, dietary, physical activity and lifestyle evaluation. Blood sampling for determination of blood lipid indices, glucose metabolism, adiponectin, lipoprotein-associated phospholipase A2 (Lp-PLA2), inflammation and oxidative stress parameters was also performed. Stool A. muciniphila presence and levels were determined by quantitative PCR and subjects were grouped based on bimodal distribution of levels (Low vs High). A. muciniphila was detected in 88.6% of participants. Overweight/obese (OW/OB) subjects were more prone in low bimodal levels of A. muciniphila compared to normal-weight (NW) individuals (58.75 vs 27.59%, P=0.004), with a 4-time greater likelihood after multi-adjusted logistic regression analysis (P=0.016). Levels of A. muciniphila were negatively associated with total cholesterol/high-density lipoprotein cholesterol (TC/HDL-C) ratio (log10:-0.009±0.004, P=0.033), whereas detection of this bacterium was negatively associated with both TC/HDL-C ratio (log10: -0.049±0.023, P=0.036) and low-density lipoprotein cholesterol/HDL-C ratio (-0.407±0.176, P=0.023). Furthermore, low bimodal levels of A. muciniphila were positively associated with fasting blood glucose (log10: 0.018±0.009, P=0.037). In terms of inflammation markers, levels of A. muciniphila were positively associated with soluble cluster of differentiation-14 (sCD14) (log10: 0.012±0.004, P=0.003) and faecal detection of this bacterium had a positive association with anti-inflammatory interleukin 10 levels (log10: 0.325±0.131, P=0.015). In addition, A. muciniphila levels were positively associated with total adiponectin (log10: 0.046±0.015, P=0.002), whereas low bimodal levels of A. muciniphila had an inverse relationship with this blood marker (log10: -0.131±0.053, P=0.016). In conclusion, we confirmed the previously reported association of A. muciniphila with metabolic health for the first time in a Greek urban population; furthermore, we shed some light to novel atherosclerotic risk markers with rather unexplored connections with A. muciniphila colonisation patterns in human subjects.

Amino acid profile and metabolic syndrome in a male Mediterranean population: A cross-sectional study.

BACKGROUND AND AIMS: The metabolic syndrome (MetS) refers to a cluster of clinically relevant factors that increases the risk of cardiovascular diseases and all-cause mortality. Circulating levels of several amino acids and metabolites related to one-carbon metabolism have been associated with cardiometabolic risk factors and MetS. We aimed to identify the amino acid profile that is significantly associated with MetS among an all male Mediterranean population. METHODS AND RESULTS: One hundred middle-aged men (54.6 ± 8.9 years) participated in a cross-sectional study carried out during 2011-2012. The International Diabetes Federation (IDF) criteria were used to define MetS. Fasting plasma levels of 20 common amino acids and 15 metabolites related to amino acid and one-carbon metabolism were measured using gas chromatography (GC-MS/MS) and liquid chromatography tandem mass spectrometry (LC-MS/MS). Principal components analysis was applied. Fifty-six participants fulfilled the IDF criteria for defining MetS. Five factors were extracted from the 35 measured metabolites. The branched-chain amino acids/aromatic amino acids (BCAA/AAA) related pattern and the glutamine/glycine/serine/asparagine (Gln/Gly/Ser/Asn) related pattern were significantly associated with MetS (odds ratio, 95% confidence interval; 6.41, 2.43-16.91, and 0.47, 0.23-0.96, respectively) after adjustment for age, current smoking status, physical activity level and medical treatment for hypertension, dyslipidaemia, type 2 diabetes mellitus. Further adjustment for liver function markers (i.e. glutamic oxaloacetic transaminase, glutamic pyruvic transaminase, and γ-glutamyltransferase), and plasma adiponectin levels did not significantly affect the associations. CONCLUSION: The BCAA/AAA pattern was positively associated, while the Gln/Gly/Ser/Asn pattern was inversely associated with established cardiometabolic risk factors and MetS. Plasma adiponectin levels or markers of liver function did not significantly affect these associations.

Associations between dietary intake and the presence of the metabolic syndrome in patients with non-alcoholic fatty liver disease.

BACKGROUND: Although dietary habits have been associated with the likelihood of the metabolic syndrome (MetS) in the general population, similar associations in non-alcoholic fatty liver disease (NAFLD) patients have not been explored. The aim of this cross-sectional study was to assess the presence of the MetS and to explore its potential association with dietary habits in a sample of NAFLD patients. METHODS: Seventy-three adult patients with recent NAFLD diagnosis based on elevated liver enzyme levels and evidence of hepatic steatosis on ultrasound were enrolled. Participants' habitual food consumption was retrospectively assessed through a food frequency questionnaire and adherence to the Mediterranean diet (MD) was assessed via the Mediterranean Diet Score (MedDietScore). The presence of the MetS was defined as the concomitant presence of at least three of its individual components, according to the criteria proposed by a recent joint statement of several major organisations. RESULTS: The MetS was present in 46.5% of the sample, with increased waist circumference values and decreased high-density lipoprotein cholesterol levels being the most prevalent disorders (63% and 88.7%, respectively). Consumption of refined grains [odds ratio (OR) = 1.02, 95% confidence interval (CI) = 1.00-1.05] and red meat and products (OR = 1.10, 95% CI = 1.01-1.21) were positively associated with the presence of the MetS, whereas the consumption of whole grains (OR = 0.92, 95% CI = 0.84-0.99) and MedDietScore (OR = 0.87, 95% CI = 0.76-0.99) were negatively associated, after adjusting for participants' age, sex, daily energy intake and time spent in sedentary activities. CONCLUSIONS: Low refined grain and red meat intake, high whole grain intake and high adherence to the MD were associated with lower odds of the MetS in NAFLD patients.

The relation of diet with PAF and its metabolic enzymes in healthy volunteers.

PURPOSE: Platelet-activating factor (PAF), a potent inflammatory mediator, is implicated in atherosclerosis. Its key biosynthetic enzymes are lyso-PAF acetyltransferases (lyso-PAF-AT), responsible for PAF synthesis through the remodeling route and a specific CDP-choline:1-alkyl-2-acetyl-sn-glycerol cholinephosphotransferase (PAF-CPT), responsible for its de novo biosynthesis. PAF acetylhydrolase (PAF-AH) and its extracellular isoform lipoprotein-associated phospholipase A2 catabolize PAF. The impact of diet on PAF metabolism is ill-defined. The aim was to investigate associations between PAF, its enzymes and dietary factors. METHODS: One-hundred and six (n = 106) healthy volunteers were recruited. Food-frequency questionnaires, dietary recalls, lifestyle and biochemical variables were collected. Food groups, macronutrient intake, a priori (MedDietScore) and a posteriori defined food patterns with PCA analysis, dietary antioxidant capacity (DAC), glycemic index (GI) and glycemic load were assessed. RESULTS: PAF was inversely correlated with antioxidant-rich foods (herbal drinks and coffee), the DAC as well as a dietary pattern characterized by legumes, vegetables, poultry and fish (all Ps < 0.05). PAF was positively correlated to % fat intake. Lyso-PAF-AT was also negatively associated with healthy patterns (fruits, nuts and herbal drinks, and a pattern rich in olive oil and whole-wheat products), as well as the DAC and % monounsaturated fatty acids. PAF-CPT was negatively associated with GI and coffee intake and positively with dietary cholesterol. PAF-AH was negatively associated with coffee and positively associated with alcohol consumption (all Ps < 0.05). CONCLUSIONS: In conclusion, the DAC and healthy dietary patterns were inversely associated with PAF or its biosynthetic enzymes, suggesting potential new mechanisms of the diet-disease associations.

Gender-specific distribution of selenium to serum selenoproteins: associations with total selenium levels, age, smoking, body mass index, and physical activity.

The epidemiology of selenium (Se) is mainly based on the determination of total serum selenium levels (TSe) which by many aspects is an inadequate marker of Se status. In this study we applied a recently developed LC-ICP-MS method, for the determination of the selenium content of the three main serum selenium-containing proteins, in a subcohort of the ATTICA study. This enables us to investigate whether the selenium distribution to selenoproteins may correlate with demographic (age, gender) and lifestyle variables (smoking, physical activity) that are crucial for the development of chronic diseases. A sub-sample from the ATTICA Study, consisted of 236 males (40 ± 11 years) and 163 females (38 ± 12 years), was selected. The selenium content of glutathione peroxidase (GPx-3), selenoprotein P (SelP) and selenoalbumin (SeAlb) was determined in serum by LC-ICP/MS method. We found that 26% of TSe is found in GPx-3, 61% in SelP and 13% in SeAlb. We have assessed the different ratios of selenoproteins' selenium content (Se-GPX-3/Se-SelP, Se-GPX-3/Se-SeAlb, Se-SelP/Se-SeAlb), showing that people with similar TSe may have different distribution of this selenium to selenoproteins. Total selenium levels and gender are the variables that mostly affect selenium distribution to selenoproteins while age, smoking, physical activity and BMI do not significantly influence selenium distribution. In conclusion, the simultaneous determination of the selenium content of serum selenium-containing selenoproteins is necessary for a thorough estimation of selenium status. The ratio of the Se content between selenoproteins may be proven a novel, valid marker of selenium status.

Effect of Robola and Cabernet Sauvignon extracts on platelet activating factor enzymes activity on U937 cells.

A number of studies support the anti-atherogenic effect of wine compounds. The scope of this study was to examine the effect of a red (Cabernet Sauvignon-CS) and a white (Robola-R) wine, as well as resveratrol and quercetin, on the platelet activating factor (PAF) biosynthetic enzymes, acetyl-CoA:lyso-PAF acetyltransferase (lyso-PAF-AT) and DTT-insensitive CDP-choline 1-alkyl-2-acetyl-sn-glycerol cholinephosphotransferase (PAF-CPT), and its main catabolic enzyme (PAF acetylhydrolase; PAF-AH), on U937 cells, in cell free and in intact cell experiments. In cell free experiments, phenolic compounds and wine extracts inhibited PAF biosynthetic enzymes, however in higher concentrations than intact cell experiments. In the latter cases, polar lipids of both wines inhibited in the same order of magnitude the action of lyso-PAF-AT and of PAF-CPT. The water fractions possessed a dual action, in lower concentrations they activated both enzymes, while in higher concentrations only inhibited PAF-CPT. All fractions either did not affect or slightly activated PAF-AH activity. In conclusion, wine compounds may exert their anti-inflammatory activity by reducing PAF levels through modulation of the PAF metabolic enzymes.

Pretreatment with sevoflurane attenuates direct lung injury.

BACKGROUND: Sevoflurane exerts effects on pulmonary cells that could protect against lung injury. We evaluated the potential of pretreatment with sevoflurane to attenuate lipopolysaccharide (LPS)-induced lung injury. METHODS: LPS was administered intratracheally in Wistar rats to induce lung injury. Sevoflurane was administered for 30 min at 0.25, 0.5 or 1.0 MAC 15 min before LPS or for 30 min at 0.5 MAC 24 hours before LPS. After initial analysis of bronchoalveolar lavage fluid (BALF) cells and total protein, the group of 0.5 MAC 15 min before LPS was further analyzed for surfactant aggregates subfractions, plasma malondialdehyde levels and lung histology. RESULTS: LPS instillation resulted in neutrophils sequestration in the lungs, loss of alveolar macrophages, increased BALF total protein and decreased large surfactant aggregates. Only inhalation of sevoflurane for 30 min at 0.5 MAC 15 min before LPS installation effectively reduced neutrophil accumulation, preserved alveolar epithelial cells and reduced total protein content in BALF. This regimen also reduced plasma malondialdehyde levels and increased large surfactant aggregates, despite the application of mechanical ventilation. This effect was preserved after LPS instillation and the favorable composition of surfactant was maintained. CONCLUSION: Pretreatment with sevoflurane effectively attenuates direct severe lung injury, possibly by inhibition of neutrophil accumulation and alteration of the surfactant composition.

Effect of different amounts of coffee on dietary intake and appetite of normal-weight and overweight/obese individuals.

OBJECTIVE: To investigate the effects of different coffee amounts on dietary intake and appetite feelings in normal-weight and overweight/obese individuals. DESIGN AND METHODS: Thirty-three volunteers (16 normal-weight, 17 overweight/obese) participated in three trials: they consumed a standard breakfast along with 200 ml of either coffee with 3 or 6 mg caffeine/kg body weight (Coffee 3 and Coffee 6, respectively), or water. At fasting and at standard time points for the 3 h following breakfast/drink consumption participants recorded their appetite feelings on visual analogue scales. At 180 min, participants consumed an ad libitum meal and the next day they recalled their food intake during the experimental day. RESULTS: A significant intervention effect was found for the energy intake of the ad libitum meal (P = 0.05) and of the whole day (P = 0.02) only in overweight/obese individuals. Specifically, Coffee 6 resulted in a reduced energy intake during the ad libitum meal compared to Coffee 3 (P = 0.03) and in the total day compared to both water (P = 0.04) and Coffee 3 (P = 0.008). No effect was observed for the appetite feelings. CONCLUSIONS: A moderate coffee amount can effectively reduce energy intake in the following meal and in the total day compared to lower or no coffee intake in overweight/obese participants.

Effects of highly active antiretroviral therapy on platelet activating factor metabolism in naive HIV-infected patients: ii) study of the abacavir/lamivudine/efavirenz HAART regimen.

Human Immunodeficiency Virus (HIV)-infected patients are at increased risk for cardiovascular diseases partly due to chronic inflammation. Some antiretroviral drugs and Highly Active Anti-Retroviral Therapy (HAART) regimens seem to be related and amplify this increased risk, especially the ones containing abacavir. Platelet-Activating-Factor (PAF) is a potent inflammatory mediator that is implicated in both cardiovascular diseases and HIV-related manifestations. Our objective is to study the in vivo effect of the abacavir/lamivudine/efavirenz first-line HAART regimen on PAF metabolism in HIV-infected patients. The specific activities of PAF basic biosynthetic enzymes in leukocytes and platelets, PAF-cholinephosphotransferase (PAF-CPT) and lyso-PAF-acetyltransferase (Lyso-PAF-AT), but also those of PAF-basic catabolic enzymes, PAF acetylhydrolase (PAF-AH) in leukocytes and platelets and Lipoprotein-associated-Phospholipase-A2 (LpPLA2) in plasma, were measured in blood samples of 10 asymptomatic naïve male HIV-infected patients just before and after 1, 3 and 6 months of treatment. CD4 cell counts, viral load and several biochemical markers were also measured in the same blood samples of these patients. The repeated ANOVA measures and the Pearson r criterion were used for studying statistical differences and correlations - partial correlations respectively. Even though viral load was decreased and CD4 cell counts were beneficially increased after treatment with the abacavir/lamivudine/efavirenz regimen, the main enzyme of the remodelling PAF-synthesis that is implicated in pro-atherogenic inflammatory procedures, Lyso-PAF-AT activity, was increased at 3 months of treatment in both leukocytes and platelets, while the main enzyme of PAF-degradation, PAF-AH, was increased as a response only in leukocytes at the 3rd month. Although the abacavir/lamivudine/efavirenz HAART regimen exhibits very efficient antiretroviral activities, on the other hand it induces an in vivo transient increase in the inflammation-related remodeling PAF-biosynthetic pathway. This finding supports the hypothesis of inflammation-mediated increased cardiovascular risk in HIV-infected patients during the first months of abacavir-containing HAART.

Vitamin D receptor activators upregulate and rescue podocalyxin expression in high glucose-treated human podocytes.

BACKGROUND: Vitamin D is beneficial in human and experimental chronic kidney disease, the leading cause of which is diabetic nephropathy. Vitamin D through its receptor, VDR, provides renal protection in diabetic nephropathy, but limited data exist about its effect on podocytes. Renal podocytes form the main filtration barrier possessing a unique phenotype maintained by proteins including podocalyxin and nephrin, the expression of which is suppressed in pathological conditions. METHODS: We used immortalized human podocytes (human glomerular epithelial cells, HGEC) to assess podocalyxin and nephrin expression after treatment with 1,25-dihydroxyvitamin D3 (calcitriol) and its analogue paricalcitol. The involvement of VDR was investigated by silencing with hVDR-siRNA and ChIP analysis. RESULTS: HGEC exhibit high glucose-mediated downregulation of podocalyxin and nephrin, loss of which has been linked with loss of the permselective renal barrier and proteinuria. Calcitriol and paricalcitol reversed high glucose-induced decrease of nephrin and significantly enhanced podocalyxin expression in podocytes cultured in high glucose. HGEC express VDR and retinoid X receptor (RXR). In the presence of calcitriol and paricalcitol, VDR expression was upregulated and VDR colocalized with RXR in the nucleus. VDR knockdown abolished the protective action of calcitriol and paricalcitol on podocalyxin expression indicating that podocalyxin activation of expression is partly mediated by VDR. Furthermore, VDR specifically regulates podocalyxin expression by bounding to a site upstream of the podocalyxin promoter. CONCLUSION: Vitamin D analogues maintain and, furthermore, re-activate the expression of specialized components of podocytes including podocalyxin, hence they provide protection against loss of the permselective renal barrier, with molecular mechanisms elucidated herein.

Osteoprotegerin and nuclear factor-kappaB ligand are associated with leptin and adiponectin levels, in apparently healthy women.

OBJECTIVES: We investigated the relationship between the major bone turnover markers, i.e., Osteoprotegerin (OPG) and Receptor activator of nuclear factor-kappaB ligand (RANKL) and serum adipokines (leptin, adiponectin) levels in a sample of apparently healthy women. METHODS: A random sample which consisted of 80 females (18-71 years) was studied. Elisa method was used to measure the OPG, RANKL and the leptin, adiponectin levels in females' serum. RESULTS: OPG values were inversely correlated with leptin (rho = -0.38, p = 0.002) and positively correlated with age (rho = 0.27, p=0.01) and body mass index (rho = 0.29, p=0.009). RANKL values were inversely correlated with adiponectin (rho = -0.23, p = 0.06) and age (rho = -0.30, p=0.01). Additionally, OPG was higher in post- as compared to pre-menopausal women. Further data analysis adjusting for potential confounders revealed that the OPG/RANKL ratio was positively associated with adiponectin and inversely associated with leptin levels independent of the effect of age, body mass index and menopausal status. CONCLUSIONS: These results reveal that leptin circulating levels are inversely associated with serum OPG/RANKL ratio among healthy women.

Dietary habits of Greek adults and serum total selenium concentration: the ATTICA study.

PURPOSE: The trace element selenium is an essential micronutrient for human health, and its low levels in serum are implicated in the pathogenesis of several chronic diseases. The determination of total serum selenium levels may contribute to the assessment of the health status of all populations. Since the serum selenium levels are highly affected by diet, we assessed its association with the dietary habits of Greek adults. METHODS: Serum selenium levels were determined with inductively coupled plasma mass spectrometry in a cohort of 506 participants (men: 296, women: 210) aged 18-75 from the ATTICA study. Food consumption was evaluated with a validated food-frequency questionnaire. RESULTS: Evaluation of the relationship between serum total selenium with major food groups and beverages by multi-adjusted analysis revealed that serum selenium was positively correlated with the consumption of red meat (2.37 ± 0.91, p = 0.01) while the consumption of other selenium-containing foods (i.e., fish, cereals, dairy products, vegetables) did not demonstrate such a relationship. Moreover, principal component analysis revealed that the adoption of a vegetarian type of diet is inversely correlated with total selenium (-3.94 ± 2.28, p = 0.08). CONCLUSIONS: Among the dietary habits that were examined, red meat seems to be the major determinant of serum selenium in Greek adults.

Dietary antioxidant capacity and concentration of adiponectin in apparently healthy adults: the ATTICA study.

BACKGROUND/OBJECTIVES: This study aimed at evaluating the relationship of adiponectin concentration with total dietary antioxidant capacity in free-living, apparently healthy adults from the ATTICA study. SUBJECTS/METHODS: A random subsample from the ATTICA study, consisting of 310 men (40+/-11 years) and 222 women (38+/-12 years), was selected. Adiponectin, along with other inflammatory markers, was measured in fasting participants. Dietary habits were evaluated using a food frequency questionnaire and the dietary antioxidant capacity was based on published values of Italian foods measured by three different assays: ferric-reducing antioxidant power (FRAP), total radical-trapping antioxidant parameters (TRAP) and trolox-equivalent antioxidant capacity (TEAC). RESULTS: Positive associations were observed between dietary antioxidant capacity and adiponectin concentration, as assessed with FRAP (b+/-s.e.=0.012+/-0.005, P=0.018 per 1 mmol Fe (II)/day), TRAP (b+/-s.e.=0.030+/-0.013, P=0.017 per 1 mmol trolox equivalent/day) and TEAC (b+/-s.e.=0.025+/-0.012, P=0.042, per 1 mmol trolox equivalent/day) in multiadjusted analysis. Moreover, a negative relation of dietary antioxidant indices with inflammatory markers was revealed. CONCLUSIONS: Diets with high antioxidant capacity are related to increased adiponectin levels. An adiponectin-mediated route through which antioxidant-rich foods exert beneficial effects against inflammation and cardiovascular diseases can be thus hypothesized.

Effects of baseline serum levels of Se on markers of eccentric exercise-induced muscle injury.

Inflammation and oxidative stress have been implicated in the mechanism of eccentric exercise-induced muscle injury. This study examined whether baseline serum levels of selenium (Se), a trace element that participates in both antioxidant and anti-inflammatory systems, affects the overall response to injury. Thirteen males performed 36 maximal eccentric actions with the elbow flexors of the non-dominant arm on a motorized dynamometer. Venous blood samples were collected immediately before and after exercise at 2, 24, 48, 72 and 96 hours. Established indicators of muscle damage such as maximum isometric torque (MIT), range of motion (ROM), relaxed arm angle (RANG), flexed arm angle (FANG), arm circumference (CIRC), muscle soreness and serum levels of creatine kinase (CK) and lactate dehydrogenase (LDH) were determined at the same time points. Baseline serum levels of Se were also measured. Complementary data regarding assessment of Se status were retrieved by the use of a semi-quantitative food frequency questionnaire. All measures changed significantly (p<0.05) after exercise. The main finding of this study was that baseline Se serum levels were associated inversely with CK, LDH and FANG and positively with MIT and ROM (p<0.05). These data suggest that beyond overt Se deficiency, suboptimal Se status possibly worsens muscle functional decrements subsequent to eccentric muscle contractions.

Biological activity of total lipids from red and white wine/must.

Wine is an essential component of the Mediterranean diet, and it is thought to exert a protective effect against coronary heart disease. Although many efforts have been made to determine the protective compounds in wines, their exact nature and how they are involved in the protection mechanisms are still unclear. In this study, total lipids, total polar lipids, and total neutral lipids of five wines and three musts were tested in vitro for their ability to induce washed rabbit platelet aggregation and/or to inhibit platelet activating factor (PAF) induced aggregation. The results showed that the biological activity of wine/must total lipids can be attributed mainly to total polar lipids. In the red wine Cabernet Sauvignon, we fractionated total neutral lipids, total polar lipids, and pigments by HPLC. Each fraction was tested in vitro for its biological activity. Structural data of the most active fractions, based on biological, chemical, and spectral methods, are also presented.

Separation of biologically active lipids from red wine.

A number of lines of evidence suggest that red wine exerts a protective effect against coronary heart disease, but the nature of the protective compounds is unclear and the mechanism is incompletely understood. In this study, total lipids of a Greek red wine were separated into neutral and polar lipids. Polar lipids were further separated into glyco- and phospholipids, which were fractionated by HPLC. Each lipid fraction was tested in vitro for its ability to inhibit platelet-activating factor (PAF) and thrombin-induced washed rabbit platelet aggregation and/or to cause platelet aggregation. A significant number of glyco- and phospholipids that exerted the above biological activities were detected. Structural data of an active phosphoglycolipid are also provided. trans-Resveratrol demonstrated also a dose-dependent inhibition of PAF-induced platelet aggregation along with the already reported inhibitory activity against thrombin and adenosine-5'-diphosphate. Because it has already been reported that PAF is involved in atheromatosis generation, the existence of PAF inhibitors in red wine may contribute to the protective role of red wine against atherosclerosis.

Lipid fractions with aggregatory and antiaggregatory activity toward platelets in fresh and fried cod (Gadus morhua): correlation with platelet-activating factor and atherogenesis.

Cod (Gadus morhua) is a popular part of the diet in many countries on both sides of the North Atlantic; in most cases it is consumed fried. In this study, total lipids of cod muscle were separated into neutral and polar lipids, which were further fractionated by HPLC. The lipid fractions were tested in vitro, against washed rabbit platelets, for the probable existence of lipid compounds that either exhibit an action similar to that of platelet-activating factor (PAF) or inhibit the action of PAF. The platelet bioassay was used to evaluate total lipids, total polar lipids, and total neutral lipids, before any further separation. Detection of these compounds in fresh and fried cod could be used to evaluate the nutritional value of this important fish. The in vitro biological study of lipids showed that in fresh cod lipid fractions, ranges of PAF-like and anti-PAF-like activities were present, whereas in fried cod lipid fractions, both neutral and polar, anti-PAF activities were mainly observed. Because it has already been reported that PAF is involved in atheromatosis generation, the existence of PAF inhibitors in cod may contribute to the possible protective role of fish, in this case cod, against atherosclerosis.