Does Yogurt Enriched with Platelet-Activating Factor Inhibitors from Olive Oil By-Products Affect Gut Microbiota and Faecal Metabolites in Healthy Overweight Subjects? (A randomized, parallel, three arm trial.)

OBJECTIVE

The effect of the daily consumption of a low-fat yogurt (150 g) enriched with Platelet-Activating Factor receptor (PAF-R) antagonists, or the plain one, on gut microbiota and faecal metabolites was investigated in healthy overweight subjects.

METHODS

A randomized, three-arm, double-blind, placebo-controlled, parallel-group study was performed that lasted 8 weeks. Blood and stools were collected and analyzed before and after the intervention.

RESULTS

Our findings revealed that the intake of the enriched yogurt resulted in a significant increase in the levels of Bifidobacterium spp., Clostridium perfringens group and Firmicutes-to-Bacteroidetes (F/B) ratio. On the other hand, a significant increase in the levels of Lactobacillus and C. perfringens group was detected after the intake of the plain yogurt. The increase in the levels of C. perfringens group was inversely associated with the plasma catabolic enzyme of PAF, namely LpPLA2 (lipoprotein-associated phospholipase A2), a cardiovascular risk marker that has been linked with inflammation and atherosclerosis. Moreover, in the enriched with PAF-R antagonists yogurt group, the increased levels of C. perfringens group were also associated with lower PAF action assessed as ex vivo human platelet-rich plasma (PRP) aggregation. Additionally, a higher % increase in molar ratio of Branched Short Chain Fatty Acids (BSCFAs) was detected for both yogurt groups after the 8 week-intervention compared to control. The consumption of the enriched yogurt also resulted in a significant drop in faecal caproic levels and a trend for lower ratio of butyrate to total volatile fatty acids (VFAs) compared to baseline levels.

CONCLUSION

Yogurt consumption seems to favorably affect gut microbiota while its enrichment with PAF-R antagonists from olive oil by-products, may provide further benefits in healthy overweight subjects.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov (NCT02259205).

Ketogenic Diet and Vitamin D Metabolism: A Review of Evidence

The ketogenic diet (KD), which is low in carbohydrates and high to normal in fat and protein, has been traditionally used in epilepsy for the last 100 years. More recently, its application in obesity has been introduced. The present review aimed to investigate the effects of the KD on vitamin D. In total, five studies were done in healthy adults, one in subjects with type 2 diabetes, and seven in subjects with epilepsy that assessed the levels of vitamin D pre- and post-intervention. In the majority of studies, increases in circulating vitamin D were reported. The relationship of the KD with vitamin D was explained through several mechanisms: ketone bodies, macronutrient intake, the status levels of other fat-soluble vitamins, weight loss, changes in the hormonal milieu, and effects on gut microbiota. Moreover, potential nutrient-gene-related interactions were discussed. There is still a need to conduct multiple arm studies to compare the effects of the KD versus other diets and better decipher the particular effects of the KD on vitamin D levels and metabolism. Moreover, differentiations of the diet's effects according to sex and genetic makeup should be investigated to prescribe KDs on a more personalized basis.

Is there an interplay between the SARS-CoV-2 spike protein and Platelet-Activating factor?

Previous publications have reported a potent effect of COVID-19 on platelet function and that the Spike protein enhances washed human platelet aggregation induced by various agonists. This study aims to evaluate whether mRNA vaccination for COVID-19 affects human platelet-rich plasma (hPRP) aggregation response, whether a recombinant Spike protein modulates PAF-induced aggregation in hPRP and in washed rabbit platelets (WRP), and to investigate the effect of recombinant Spike protein on the PAF production in the U-937 cell line. Our results showed that PRP from vaccinated individuals exhibited ex vivo lower EC₅₀ values in response to PAF, ADP, and collagen. Platelet incubation with the Spike protein alone did not induce aggregation either in hPRP or in WRP, but resulted in augmentation of in vitro PAF-induced aggregation in hPRP from non-vaccinated individuals and in WRP. When PRP from vaccinated individuals was incubated with the Spike protein and PAF was subsequently added, elimination of the secondary wave of the biphasic aggregation curve was recorded compared with the aggregation induced by PAF alone. Collagen-induced in vitro aggregation was dose-dependently reduced when platelets were pre-incubated with the Spike protein in all tested aggregation experiments. Stimulation of U-937 by the Spike protein induced an increase in intracellular PAF production accompanied by elevation of the activities of all three PAF biosynthetic enzymes. In conclusion, since the Spike protein appears to modulate PAF production and activity, the use of compounds that act as PAF inhibitors, could be considered at least in mild cases of patients infected with SARS-CoV-2.

Consumption of Farmed Fish, Fed with an Olive-Pomace Enriched Diet, and Its Effect on the Inflammatory, Redox, and Platelet-Activating Factor Enzyme Profile of Apparently Healthy Adults: A Double-Blind Randomized Crossover Trial

A fish-rich diet has a beneficial effect on cardiovascular health. The platelet activating factor (PAF) is involved in the development of atherosclerosis, and in vitro results support the regulating action of bioactive nutrients on PAF metabolism. The purpose of this study is to examine whether the consumption of farmed fish fed with an olive-pomace enriched diet (EF) affects PAF metabolism and the markers of inflammation and oxidative stress compared to the consumption of conventionally fed farmed fish (CF). Thirty apparently healthy adults completed a randomized double-blind crossover trial, during which they consumed both CF and EF twice a week for 8 weeks with a six-week washout period in between. The activities of PAF acetylhydrolase (PAF-AH), lysoPAF acetyltransferase (lysoPAF-AT), DTT-insensitive CDP-choline: 1-alkyl-2-acetyl-sn-glycerol-choline-phosphotransferase (PAF-CPT) in leukocytes, and lipoprotein-associated phospholipase A₂ (LpPLA₂) in serum were determined. The quantities of interleukin-6 (IL-6), high sensitivity C-reactive protein (hsCRP), oxidized LDL (ox-LDL), thiobarbituric acid-reactive substances (TBARS), and glutathione peroxidase (GPx), as well as the serum oxidation, were also determined. Both types of fish exerted similar effects as there were no statistically significant differences between the two interventions except for an elevated PAF-CPT and reduced arachidonic acid (AA) in the red blood cell (RBC) membrane lipids after the EF intake.

The effect of moderate wine consumption on cytokine secretion by peripheral blood mononuclear cells: A randomized clinical study in coronary heart disease patients

Many studies conclude that wine consumption is related to lower risk for cardiovascular diseases partially through the amelioration of inflammatory biomarkers. The aim of the present study was to examine the effects of wine consumption on the inflammatory response and to compare these effects with the consumption of similar amount of alcohol without the wine micro-constituents in cardiovascular disease patients. Therefore, a randomized, single-blind, controlled, three-arm parallel intervention study was designed. Cardiovascular disease patients were randomly assigned to one of the three groups. In Group A participants consumed no alcohol, in Group B (ethanol group) and Group C (wine group) participants consumed 27 g of alcohol per day. Biological samples were collected at the beginning, on the 4th and 8th week and several biomarkers were measured. Peripheral blood mononuclear cells that were isolated from patients were incubated under basal and inflammatory conditions for 4 and 24 h and the secretion of interleukin 1β (IL-1β) and tumor necrosis factor α (TNFα) was measured. No significant difference was observed among the three groups before the initiation or during the intervention in the most soluble biomarkers. Higher TNFα secretion by peripheral blood mononuclear cells was observed at basal conditions in the ethanol group both at 4 and 24 h of incubation versus baseline secretion. Furthermore, lower secretion of the ΤNFα was observed after 8 weeks of intake in the wine group versus the ethanol group, both at 4 and 24 h of incubation. In conclusion, the light to moderate wine consumption for 8 weeks revealed an attenuation of the ethanol consumption effect on cytokine secretion at basal conditions from the patients' peripheral blood mononuclear cells.

Consumption of Enriched Yogurt with PAF Inhibitors from Olive Pomace Affects the Major Enzymes of PAF Metabolism: A Randomized, Double Blind, Three Arm Trial

Platelet-activating factor (PAF), a proinflammatory lipid mediator, plays a crucial role in the formation of the atherosclerotic plaque. Therefore, the inhibition of endothelium inflammation by nutraceuticals, such as PAF inhibitors, is a promising alternative for preventing cardiovascular diseases. The aim of the present study was to evaluate the impact of a new functional yogurt enriched with PAF inhibitors of natural origin from olive oil by-products on PAF metabolism. Ninety-two apparently healthy, but mainly overweight volunteers (35-65 years) were randomly allocated into three groups by block-randomization. The activities of PAF's biosynthetic and catabolic enzymes were measured, specifically two isoforms of acetyl-CoA:lyso-PAF acetyltransferase (LPCATs), cytidine 5'-diphospho-choline:1-alkyl-2-acetyl-sn-glycerol cholinephosphotransferase (PAF-CPT) and two isoforms of platelet activating factor acetylhydrolase in leucocytes (PAF-AH) and plasma (lipoprotein associated phospholipase-A₂, LpPLA₂). The intake of the enriched yogurt resulted in reduced PAF-CPT and LpPLA₂ activities. No difference was observed in the activities of the two isoforms of lyso PAF-AT. In conclusion, intake of yogurt enriched in PAF inhibitors could favorably modulate PAF biosynthetic and catabolic pathways.

Evaluation of Anti-Inflammatory, Anti-Platelet and Anti-Oxidant Activity of Wine Extracts Prepared from Ten Different Grape Varieties

Inflammation, thrombosis and oxidative stress are rarely studied together when wine's biological activity is concerned; hence the existing literature lacks a holistic point of view in the biological outcome. The scope of the present study is to parallel evaluate the effect of wine extracts on those mechanisms. Ten wine varieties and two different extraction methods were used leading to five extracts for each wine: total lipids (TL) and fractions with different phenolic compound classes (FI, FII, FIII and FIV). Their effect on oxidative stress, platelet aggregation and the secretion of cytokines from mononuclear cells was measured and a biological score was calculated. FII of white wines is the most potent extract and the extracts FIII and TL are following. Specifically, FII had higher anti-oxidant and anti-inflammatory score while all three fractions had a similar anti-platelet score. Furthermore, FII and FIII extracts were the most potent red wine extracts and revealed the highest anti-oxidant and anti-inflammatory scores. White wine FII extracts were more potent than the red wine ones while FI and FIV extracts of red wine were more potent than the white wine ones. In conclusion, the protective effect of a wine is independent of its color but is strongly associated with its microconstituents profile. FII extract revealed the highest biological score and further examination is needed in order to identify the compounds that are responsible for the aforementioned actions.

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.

Macronutrient content and food exchanges for 48 Greek Mediterranean dishes

AIM

The purpose of the present study was to facilitate the translation of traditional Greek Mediterranean recipes into food exchanges for diabetes. Moreover, it provides a useful food list for meal planning, which can be used by health professionals and nutritionists, as well as researchers and the public.

METHODS

A total of 48 traditional Greek Mediterranean dishes were selected in order to include appetisers, sauces, salads, pies, dishes with vegetables and legumes as well as egg, pasta, rice, meat, fish and poultry-based dishes. The macronutrient content of each recipe (carbohydrate, fat, protein and dietary fibre) was estimated with the use of the USDA database and Greek food composition tables. Then, in order to calculate the food exchanges per serve, an approximation method was followed as suggested in the literature.

RESULTS

The Mediterranean Greek dishes contain a considerable amount of vegetables and dietary fibre, and their energy content mainly derives from olive oil. For each serve, carbohydrate, non-starchy vegetable, protein (lean, medium or high fat), milk and fat exchanges are provided. Moreover, the type of fat that each recipe contains is reported.

CONCLUSIONS

The presented data offer a chance for health professionals to efficiently plan Mediterranean-type meals, ensuring more sophisticated dietetic advice, higher standards of medical nutrition therapy and greater patient self-efficacy.

Structural elucidation of olive pomace fed sea bass (Dicentrarchus labrax) polar lipids with cardioprotective activities

The purpose of this study was to structurally characterise the polar lipids of sea bass (Dicentrarchus labrax), fed with an experimental diet containing olive pomace (OP), that exhibit cardioprotective activities. OP has been added to conventional fish oil (FO) feed at 4% and this was the OP diet, having been supplemented as finishing diet to fish. Sea bass was aquacultured using either FO or OP diet. At the end of the dietary experiment, lipids in both samples of fish muscle were quantified and HPLC fractionated. The in vitro cardioprotective properties of the polar lipid fractions, using washed rabbit's platelets, have been assessed and the two most biologically active fractions were further analysed by mass spectrometry. The gas-chromatrograpy-mass spectrometric data shows that these two fractions contain low levels of myristic (14:0), oleic (18:1 cis ω-9) and linoleic acids (18:2 ω-6), but high levels of palmitic (16:0) and stearic acids (18:0) as well as eicosadienoic acid (20:2 ω-6). The first fraction (MS1) also contained significant levels of arachidonic acid (20:4 ω-6) and the omega-3 fatty acids: eicosapentaenoic acid (22:5) and docosahexaenoic acid (22:6). Electrospray-mass spectrometry elucidated that the lipid composition of the two fractions contained various diacyl-glycerophospholipids species, where the majority of them have either 18:0 or 18:1 fatty acids in the sn-1 position and either 22:6 or 20:2 fatty acids in the sn-2 position for MS1 and MS2, respectively. Our research focuses on the structure/function relationship of fish muscle polar lipids and cardiovascular diseases and structural data are given for polar lipid HPLC fractions with strong cardioprotective properties.