Early Metabolic Disruption and Predictive Biomarkers of Delayed-Cerebral Ischemia in Aneurysmal Subarachnoid Hemorrhage.

Delayed cerebral ischemia (DCI) following aneurysmal subarachnoid hemorrhage (aSAH) is a major cause of complications and death. Here, we set out to identify high-performance predictive biomarkers of DCI and its underlying metabolic disruptions using metabolomics and lipidomics approaches. This single-center prospective observational study enrolled 61 consecutive patients with severe aSAH; among them, 22 experienced a DCI. Nine patients without aSAH were included as validation controls. Blood and cerebrospinal fluid (CSF) were sampled within the first 24 h after admission. We identified a panel of 20 metabolites that, together, showed high predictive performance for DCI. This panel of metabolites included lactate, cotinine, salicylate, 6 phosphatidylcholines, and 4 sphingomyelins. The interplay of the metabolome and the lipidome found between CSF and plasma in our patients underscores that aSAH and its associated DCI complications can extend beyond cerebral implications, with a peripheral dimension as well. As an illustration, early biological disruptions that might explain the subsequent DCI found systemic hypoxia driven mainly by higher blood lactate, arginine, and proline metabolism likely associated with vascular NO and disrupted ceramide/sphingolipid metabolism. We conclude that targeting early peripheral hypoxia preceding DCI could provide an interesting strategy for the prevention of vascular dysfunction.

Vitamin D3 Supplementation Alleviates Left Ventricular Dysfunction in a Mouse Model of Diet-Induced Type 2 Diabetes: Potential Involvement of Cardiac Lipotoxicity Modulation.

PURPOSE: To evaluate the effectiveness of vitamin D3 supplementation, in secondary prevention, on cardiac remodeling and function, as well as lipid profile, in a mouse model of diet-induced type 2 diabetes. METHODS: Mice were fed a high fat and sucrose diet for 10 weeks. Afterward, diet was maintained for 15 more weeks and two groups were formed, with and without cholecalciferol supplementation. A control group was fed with normal chow. Glucose homeostasis and cardiac function were assessed at baseline and at the 10th and 24th weeks. Animals were killed at the 10th and 25th weeks for plasma and cardiac sample analysis. Cardiac lipid profile was characterized by LC-MS/MS. RESULTS: After 10 weeks of diet, mice exhibited pre-diabetes, mild left ventricle hypertrophy, and impaired longitudinal strain, but preserved myocardial circumferential as well as global diastolic and systolic cardiac function. After 15 more weeks of diet, animals presented with well-established type 2 diabetes, pathological cardiac hypertrophy, and impaired regional myocardial function. Cholecalciferol supplementation had no effect on glucose homeostasis but improved cardiac remodeling and regional myocardial function. After 25 weeks, non-supplemented mice exhibited increased myocardial levels of ceramides and diacylglycerol, both of which were normalized by vitamin D3 supplementation. CONCLUSION: This work brought to light the beneficial effects of cholecalciferol supplementation, in secondary prevention, on cardiac remodeling and function in a mouse model of diet-induced type 2 diabetes. Those cardioprotective effects may be, at least in part, attributed to the modulation of myocardial levels of lipotoxic species by vitamin D.

2',7'-dichlorofluorescin-based analysis of Fenton chemistry reveals auto-amplification of probe fluorescence and albumin as catalyst for the detection of hydrogen peroxide.

Fluorophore 2',7'-dichlorofluorescin (DCF) is the most frequently used probe for measuring oxidative stress in cells, but many aspects of DCF remain to be revealed. Here, DCF was used to study the Fenton reaction in detail, which confirmed that in a cell-free system, the hydroxyl radical was easily measured by DCF, accompanied by the consumption of H2O2 and the conversion of ferrous iron into ferric iron. DCF fluorescence was more specific for hydroxyl radicals than the measurement of thiobarbituric acid (TBA)-reactive 2-deoxy-D-ribose degradation products, which also detected H2O2. As expected, hydroxyl radical-induced DCF fluorescence was inhibited by iron chelation, anti-oxidants, and hydroxyl radical scavengers and enhanced by low concentrations of ascorbate. Remarkably, due to DCF fluorescence auto-amplification, Fenton reaction-induced DCF fluorescence steadily increased in time even when all ferrous iron was oxidized. Surprisingly, the addition of bovine serum albumin rendered DCF sensitive to H2O2 as well. Within cells, DCF appeared not to react directly with H2O2 but indirect via the formation of hydroxyl radicals, since H2O2-induced cellular DCF fluorescence was fully abolished by iron chelation and hydroxyl radical scavenging. Iron chelation in H2O2-stimulated cells in which DCF fluorescence was already increasing did not abrogate further increases in fluorescence, suggesting DCF fluorescence auto-amplification in cells. Collectively, these data demonstrate that DCF is a very useful probe to detect hydroxyl radicals and hydrogen peroxide and to study Fenton chemistry, both in test tubes as well as in intact cells, and that fluorescence auto-amplification is an intrinsic property of DCF.

ABCB1 (P-glycoprotein) regulates vitamin D absorption and contributes to its transintestinal efflux.

Efficient intestinal absorption of dietary vitamin D is required in most people to ensure an adequate status. Thus, we investigated the involvement of ATP binding cassette subfamily B member 1 (ABCB1) in vitamin D intestinal efflux. Both cholecalciferol (D3) and 25-hydroxycholecalciferol [25(OH)D3] apical effluxes were decreased by chemical inhibition of ABCB1 in Caco-2 cells and increased by ABCB1 overexpression in Griptites or Madin-Darby canine kidney type II cells. Mice deficient for the 2 murine ABCB1s encoded by Abcb1a and Abcb1b genes ( Abcb1-/-) displayed an accumulation of 25(OH)D3 in plasma, intestine, brain, liver, and kidneys, together with an increased D3 postprandial response after gavage compared with controls. 25(OH)D3 efflux through Abcb1-/- intestinal explants was markedly decreased compared with controls. This reduction of 25(OH)D3 transfer from plasma to lumen was further confirmed in vivo in intestine-perfused mice. Docking experiments established that both D3 and 25(OH)D3 could bind with high affinity to Caenorhabditis elegans P-glycoprotein, used as an ABCB1 model. Finally, in a group of 39 healthy male adults, a single-nucleotide polymorphism (SNP) in ABCB1 (rs17064) was significantly associated with the fasting plasma 25(OH)D3 concentration. Thus, we showed here for the first time that ABCB1 is involved in neo-absorbed vitamin D efflux by the enterocytes and that it also contributes to vitamin D transintestinal excretion and likely impacts vitamin D status.-Margier, M., Collet, X., le May, C., Desmarchelier, C., André, F., Lebrun, C., Defoort, C., Bluteau, A., Borel, P., Lespine, A., Reboul, E. ABCB1 (P-glycoprotein) regulates vitamin D absorption and contributes to its transintestinal efflux.

Impact of geographical region on urinary metabolomic and plasma fatty acid profiles in subjects with the metabolic syndrome across Europe: the LIPGENE study.

The application of metabolomics in multi-centre studies is increasing. The aim of the present study was to assess the effects of geographical location on the metabolic profiles of individuals with the metabolic syndrome. Blood and urine samples were collected from 219 adults from seven European centres participating in the LIPGENE project (Diet, genomics and the metabolic syndrome: an integrated nutrition, agro-food, social and economic analysis). Nutrient intakes, BMI, waist:hip ratio, blood pressure, and plasma glucose, insulin and blood lipid levels were assessed. Plasma fatty acid levels and urine were assessed using a metabolomic technique. The separation of three European geographical groups (NW, northwest; NE, northeast; SW, southwest) was identified using partial least-squares discriminant analysis models for urine (R² X: 0·33, Q²: 0·39) and plasma fatty acid (R² X: 0·32, Q²: 0·60) data. The NW group was characterised by higher levels of urinary hippurate and N-methylnicotinate. The NE group was characterised by higher levels of urinary creatine and citrate and plasma EPA (20 : 5 n-3). The SW group was characterised by higher levels of urinary trimethylamine oxide and lower levels of plasma EPA. The indicators of metabolic health appeared to be consistent across the groups. The SW group had higher intakes of total fat and MUFA compared with both the NW and NE groups (P≤ 0·001). The NE group had higher intakes of fibre and n-3 and n-6 fatty acids compared with both the NW and SW groups (all P< 0·001). It is likely that differences in dietary intakes contributed to the separation of the three groups. Evaluation of geographical factors including diet should be considered in the interpretation of metabolomic data from multi-centre studies.

Effect on blood lipids of two daily servings of Camembert cheese. An intervention trial in mildly hypercholesterolemic subjects.

As a concentrated source of saturated fat, cheese consumption is considered to be associated with increased cholesterolemia and generally forbidden in dietary guidelines for adults with hypercholesterolemia. The aim of this study was to evaluate the impact of saturated fatty acids on lipid parameters and blood pressure with regards to different types of dairy products: Camembert and full-fat yoghurt. One-hundred and fifty-nine moderate hypercholesterolemic subjects without treatment were instructed to consume two full-fat yoghurts (2 × 125 g) per day for 3 weeks (run-in period) and then for a further period of 5 weeks, either two full-fat yoghurts or two 30 g servings of Camembert cheese per day. We observed that over the 5-week daily consumption of two servings of Camembert cheese, blood pressure and serum lipids did not change in moderate hypercholesterolemic subjects. These results suggest that fermented cheese such as Camembert could be consumed daily without affecting serum lipids or blood pressure.

Diet modulates endogenous thrombin generation, a biological estimate of thrombosis risk, independently of the metabolic status.

OBJECTIVE: High endogenous thrombin potential (ETP) is associated with venous and arterial thrombosis. Better knowledge of environmental influences on ETP may help to prevent thrombosis. METHODS AND RESULTS: Weaning rats exhibited high ETP values that decreased in low-fat diet and remained elevated on high-fat diet. In adult rats, high-fat diet-induced ETP increase was independent of coagulation factors, obesity, and insulin resistance and negatively associated with polyunsaturated fatty acid levels. Switching from high-fat diet to low-fat diet reversed the procoagulant phenotype with a slower kinetic than the normalization of hyperinsulinemia. In humans, ETP was independent of body weight whereas it was negatively associated with nutritional markers such as the percentage of energy provided by proteins, the protein:fat ratio, circulating phenolic compounds, and omega-3 polyunsaturated fatty acid. A recommended 3-month healthy diet with reduced energy density, including lipids, decreased ETP (-21%; P<0.0001). Changes in ETP were not associated with body weight, insulin sensitivity, or coagulation factor variations, but correlated negatively with plasma docosahexaenoic acid, a nutritional status sensitive fatty acid, and compounds reflecting vegetable intake. CONCLUSIONS: Diet plays a pivotal role in regulating ETP, independently of obesity and insulin resistance. Global nutritional recommendations could be useful in primary prevention of venous thrombosis.

Prolonged dysbiosis and altered immunity under nutritional intervention in a physiological mouse model of severe acute malnutrition.

Severe acute malnutrition (SAM) is a multifactorial disease affecting millions of children worldwide. It is associated with changes in intestinal physiology, microbiota, and mucosal immunity, emphasizing the need for multidisciplinary studies to unravel its full pathogenesis. We established an experimental model in which weanling mice fed a high-deficiency diet mimic key anthropometric and physiological features of SAM in children. This diet alters the intestinal microbiota (less segmented filamentous bacteria, spatial proximity to epithelium), metabolism (decreased butyrate), and immune cell populations (depletion of LysoDC in Peyer's patches and intestinal Th17 cells). A nutritional intervention leads to a fast zoometric and intestinal physiology recovery but to an incomplete restoration of the intestinal microbiota, metabolism, and immune system. Altogether, we provide a preclinical model of SAM and have identified key markers to target with future interventions during the education of the immune system to improve SAM whole defects.

Deep phenotyping and biomarkers of various dairy fat intakes in an 8-week randomized clinical trial and 2-year swine study.

Health effects of dairy fats (DF) are difficult to evaluate, as DF intakes are hard to assess epidemiologically and DF have heterogeneous compositions that influence biological responses. We set out to find biomarkers of DF intake and assess biological response to a summer DF diet (R2), a winter DF diet (R3), and a R3 supplemented with calcium (R4) compared to a plant-fat-based diet (R1) in a randomized clinical trial (n=173) and a 2-year study in mildly metabolically disturbed downsized pigs (n=32). Conventional clinical measures were completed by LC/MS plasma metabolomics/lipidomics. The measured effects were modeled as biological functions to facilitate interpretation. DF intakes in pigs specifically induced a U-shaped metabolic trajectory, reprogramming metabolism to close to its initial status after a one-year turnaround. Twelve lipid species repeatably predicted DF intakes in both pigs and humans (6.6% errors). More broadly, in pigs, quality of DF modulated the time-related biological response (R2: 30 regulated functions, primarily at 6 months; R3: 26 regulated functions, mostly at 6-12 months; R4: 43 regulated functions, mostly at 18 months). Despite this heterogeneity, 9 functions overlapped under all 3 DF diets in both studies, related to a restricted area of amino acids metabolism, cofactors, nucleotides and xenobiotic pathways and the microbiota. In conclusion, over the long-term, DF reprograms metabolism to close to its initial biological status in metabolically-disrupted pigs. Quality of the DF modulates its metabolic influence, although some effects were common to all DF. A resilient signature of DF consumption found in pigs was validated in humans.

A Period 2 genetic variant interacts with plasma SFA to modify plasma lipid concentrations in adults with metabolic syndrome.

Genetic variants of Period 2 (PER2), a circadian clock gene, have been linked to metabolic syndrome (MetS). However, it is still unknown whether these genetic variants interact with the various types of plasma fatty acids. This study investigated whether common single nucleotide polymorphisms (SNPs) in the PER2 locus (rs934945 and rs2304672) interact with various classes of plasma fatty acids to modulate plasma lipid metabolism in 381 participants with MetS in the European LIPGENE study. Interestingly, the rs2304672 SNP interacted with plasma total SFA concentrations to affect fasting plasma TG, TG-rich lipoprotein (TRL-TG), total cholesterol, apoC-II, apoB, and apoB-48 concentrations (P-interaction < 0.001-0.046). Carriers of the minor allele (GC+GG) with the highest SFA concentration (>median) had a higher plasma TG concentration (P = 0.001) and higher TRL-TG (P < 0.001) than the CC genotype. In addition, participants carrying the minor G allele for rs2304672 SNP and with a higher SFA concentration (>median) had higher plasma concentrations of apo C-II (P < 0.001), apo C-III (P = 0.009), and apoB-48 (P = 0.028) compared with the homozygotes for the major allele (CC). In summary, the rs2304672 polymorphism in the PER2 gene locus may influence lipid metabolism by interacting with the plasma total SFA concentration in participants with MetS. The understanding of these gene-nutrient interactions could help to provide a better knowledge of the pathogenesis in MetS.