Hydrogen- and Methane-Based Breath Testing and Outcomes in Patients With Heart Failure.

BACKGROUND: Recent evidence endorses gut microbiota dysregulation in the pathophysiology of heart failure (HF). Small intestinal bacterial overgrowth (SIBO) might be present in HF and associated with poor clinical outcomes. Lactulose breath testing is a simple noninvasive test that has been advocated as a reliable indicator of SIBO. In patients with HF, we aimed to evaluate the association with clinical outcomes of the exhaled hydrogen (H2) and methane (CH4) concentrations through the lactulose breath test. METHODS AND RESULTS: We included 102 patients with HF in which lactulose SIBO breath tests were assessed. Cumulative gas was quantified by the area under the receiver operating characteristic curve of CH4 (AUC-CH4) and H2 (AUC-H2). Clinical end points included the composite of all-cause death with either all-cause or HF hospitalizations, recurrent all-cause hospitalizations, and recurrent HF hospitalizations. Medians (interquartile ranges) of AUC-H2 and AUC-CH4 were 1290 U (520-2430) and 985 U (450-2120), respectively. In multivariable analysis, AUC-H2 (per 1000 U) was associated with all-cause death/all-cause hospitalization (hazard ratio [HR] 1.21, 95% CI 1.04-1.40; P = .012), all-cause death/HF hospitalization (HR 1.20, 95% CI 1.03-1.40; P = .021), and an increase in the rate of recurrent all-cause (incidence rate ratio [IRR] 1.31, 95% CI 1.14-1.51; P < .001) and HF (IRR 1.41, 95% CI 1.15-1.72; P = .001) hospitalizations. AUC-CH4 was not associated with any of these end points. CONCLUSIONS: AUC-H2, a safe and noninvasive method for SIBO estimation, is associated with higher risk of long-term adverse clinical events in patients with HF. In contrast, AUC-CH4 did not show any prognostic value.

Hepatocyte MyD88 affects bile acids, gut microbiota and metabolome contributing to regulate glucose and lipid metabolism.

OBJECTIVE: To examine the role of hepatocyte myeloid differentiation primary-response gene 88 (MyD88) on glucose and lipid metabolism. DESIGN: To study the impact of the innate immune system at the level of the hepatocyte and metabolism, we generated mice harbouring hepatocyte-specific deletion of MyD88. We investigated the impact of the deletion on metabolism by feeding mice with a normal control diet or a high-fat diet for 8 weeks. We evaluated body weight, fat mass gain (using time-domain nuclear magnetic resonance), glucose metabolism and energy homeostasis (using metabolic chambers). We performed microarrays and quantitative PCRs in the liver. In addition, we investigated the gut microbiota composition, bile acid profile and both liver and plasma metabolome. We analysed the expression pattern of genes in the liver of obese humans developing non-alcoholic steatohepatitis (NASH). RESULTS: Hepatocyte-specific deletion of MyD88 predisposes to glucose intolerance, inflammation and hepatic insulin resistance independently of body weight and adiposity. These phenotypic differences were partially attributed to differences in gene expression, transcriptional factor activity (ie, peroxisome proliferator activator receptor-α, farnesoid X receptor (FXR), liver X receptors and STAT3) and bile acid profiles involved in glucose, lipid metabolism and inflammation. In addition to these alterations, the genetic deletion of MyD88 in hepatocytes changes the gut microbiota composition and their metabolomes, resembling those observed during diet-induced obesity. Finally, obese humans with NASH displayed a decreased expression of different cytochromes P450 involved in bioactive lipid synthesis. CONCLUSIONS: Our study identifies a new link between innate immunity and hepatic synthesis of bile acids and bioactive lipids. This dialogue appears to be involved in the susceptibility to alterations associated with obesity such as type 2 diabetes and NASH, both in mice and humans.

Altered Lipid Moieties and Carbonyls in a Wistar Rat Dietary Model of Subclinical Fatty Liver: Potential Sex-Specific Biomarkers of Early Fatty Liver Disease?

Non-alcoholic fatty liver disease (NAFLD) is a condition in which excess fat builds up in the liver. To date, there is a lack of knowledge about the subtype of lipid structures affected in the early stages of NAFLD. The aim of this study was to analyze serum and liver lipid moieties, specifically unsaturations and carbonyls, by nuclear magnetic resonance (NMR) in a subclinical Wistar rat model of NAFLD for detecting early alterations and potential sex dimorphisms. Twelve weeks of a high-fat diet (HFD) induced fat accumulation in the liver to a similar extent in male and female Wistar rats. In addition to total liver fat accumulation, Wistar rats showed a shift in lipid subtype composition. HFD rats displayed increased lipid carbonyls in both liver and serum, and decreased in unsaturated fatty acids (UFAs) and polyunsaturated fatty acids (PUFAs), with a much stronger effect in male than female animals. Our results revealed that the change in fat was not only quantitative but also qualitative, with dramatic shifts in relevant lipid structures. Finally, we compared the results found in Wistar rats with an analysis in a human patient cohort of extreme obesity. For the first time to our knowledge, lipid carbonyl levels and lipoproteins profiles were analyzed in the context of subclinical NAFLD. The association found between lipid carbonyls and alanine aminotransferase (ALT) in a human cohort of extremely obese individuals further supports the potential role of lipid moieties as biomarkers of early NAFLD.

Diabetes impairs the atrial natriuretic peptide relaxant action mediated by potassium channels and prostacyclin in the rabbit renal artery.

Diabetes is associated with increased prevalence of hypertension, cardiovascular and renal disease. Atrial natriuretic peptide (ANP) plays an important role in cardiovascular pathophysiology and is claimed to have cardioprotective and renoprotective effect in diabetic patients. The working hypothesis was that alloxan-induced diabetes might modify the vascular effects of ANP in isolated rabbit renal arteries and the mechanisms involved in such actions. Plasma ANP levels were higher in diabetic rabbits than in control rabbits. ANP (10(-12)-10(-7)M) induced a relaxation of precontracted renal arteries, which was lower in diabetic than in control rabbits. In arteries from both groups of animals, endothelium removal decreased the ANP-induced relaxation but inhibition of NO-synthesis did not modify ANP-induced relaxations. In KCl-depolarised arteries, relaxation to ANP was almost abolished both in control and diabetic rabbits. Tetraethylammonium (TEA) partly inhibited the relaxation to ANP in control rabbits but did not modify it in diabetic rabbits. Glibenclamide and 4-aminopyridine inhibited the relaxation to ANP, and these inhibitions were lower in diabetic than in control rabbits. Indomethacin potentiated the relaxation to ANP, more in control than in diabetic rabbits. In the presence of ANP the renal artery released thromboxane A(2) and prostacyclin, and the release of prostacyclin resulted decreased in diabetic rabbits. The present results suggest that diabetes produces hyporeactivity of the rabbit renal artery to ANP by mechanisms that at least include the reduced modulation by prostacyclin and a lower participation of ATP-sensitive K(+) channel (K(ATP)), voltage-sensitive K(+) channels (K(V)) and TEA-sensitive K(+) channels (K(Ca)).

Rodent models and metabolomics in non-alcoholic fatty liver disease: What can we learn?

Non-alcoholic fatty liver disease (NAFLD) prevalence has increased drastically in recent decades, affecting up to 25% of the world's population. NAFLD is a spectrum of different diseases that starts with asymptomatic steatosis and continues with development of an inflammatory response called steatohepatitis, which can progress to fibrosis. Several molecular and metabolic changes are required for the hepatocyte to finally vary its function; hence a "multiple hit" hypothesis seems a more accurate proposal. Previous studies and current knowledge suggest that in most cases, NAFLD initiates and progresses through most of nine hallmarks of the disease, although the triggers and mechanisms for these can vary widely. The use of animal models remains crucial for understanding the disease and for developing tools based on biological knowledge. Among certain requirements to be met, a good model must imitate certain aspects of the human NAFLD disorder, be reliable and reproducible, have low mortality, and be compatible with a simple and feasible method. Metabolism studies in these models provides a direct reflection of the workings of the cell and may be a useful approach to better understand the initiation and progression of the disease. Metabolomics seems a valid tool for studying metabolic pathways and crosstalk between organs affected in animal models of NAFLD and for the discovery and validation of relevant biomarkers with biological understanding. In this review, we provide a brief introduction to NAFLD hallmarks, the five groups of animal models available for studying NAFLD and the potential role of metabolomics in the study of experimental NAFLD.

Sex Dimorphism in the Metabolome of Metabolic Syndrome in Morbidly Obese Individuals.

Adult morbid obesity is defined as abnormal or excessive fat accumulation, mostly resulting from a long-term unhealthy lifestyle. Between 10% and 30% of people with obesity exhibit low cardiometabolic risk. The metabolic syndrome has been suggested as an indicator of obesity-related metabolic dysregulation. Although the prevalence of obesity does not seem to be sex-related and metabolic syndrome occurs at all ages, in the last few years, sex-specific differences in the pathophysiology, diagnosis, and treatment of metabolic syndrome have received attention. The aim of this study was to determine the prevalence of metabolic syndrome and its components in different sex and age groups in people with metabolic unhealthy obesity and to compare them with people with metabolic healthy obesity. We analyzed the metabolome in 1350 well-phenotyped morbidly obese individuals and showed that there is a strong sex-dependent association of metabolic syndrome with circulating metabolites. Importantly, we demonstrated that metabolic dysregulation in women and men with severe obesity and metabolic syndrome is age-dependent. The metabolic profiles from our study showed age-dependent sex differences in the impact of MetS which are consistent with the cardiometabolic characterization. Although there is common ground for MetS in the metabolome of severe obesity, men older than 54 are affected in a more extensive and intensive manner. These findings strongly argue for more studies aimed at unraveling the mechanisms that underlie this sex-specific metabolic dysregulation in severe obesity. Moreover, these findings suggest that women and men might benefit from differential sex and age specific interventions to prevent the adverse cardiometabolic effects of severe obesity.

Mechanisms underlying the diabetes-induced hyporeactivity of the rabbit carotid artery to atrial natriuretic peptide.

Atrial natriuretic peptide (ANP) plays an important role in the pathophysiology of the vascular complications in diabetes. The working hypothesis was that diabetes might modify the vascular actions of ANP in isolated rabbit carotid arteries and the mechanisms involved in these actions. ANP (10(-12)-10(-7)M) induced a relaxation of precontracted carotid arteries, which was lower in diabetic than in control rabbits. In arteries from both groups of animals, endothelium removal increased the ANP-induced relaxation. Isatin inhibited the relaxation to ANP both in arteries with and without endothelium. Carotid arteries from diabetic rabbits showed a decreased natriuretic peptide receptor (NPR)-A expression and an enhanced NPR-C expression. Inhibition of NO-synthesis did not modify ANP-induced relaxation in control rabbits but inhibited it in diabetic rabbits. In arteries with endothelium indomethacin enhanced the relaxation to ANP in control rabbits but did not modify it in diabetic rabbits. In endothelium-denuded arteries indomethacin inhibited the relaxation to ANP in both groups of animals. In KCl-depolarised arteries, relaxation to ANP was almost abolished both in control and diabetic rabbits. Tetraethylammonium inhibited the relaxation to ANP, and this inhibition was higher in diabetic than in control rabbits. These results suggest that diabetes produces hyporeactivity of the rabbit carotid artery to ANP by a mechanism that at least includes a reduced expression of NPR-A, an enhanced expression of NPR-C and a reduced participation of K(+)-channels. Furthermore, diabetes enhances endothelial NO release and diminishes the ratio thromboxane A(2)/prostacyclin. This increase of vasodilators could result from compensatory mechanisms counteracting the arterial hyporeactivity to ANP.

Bacterial metabolites trimethylamine N-oxide and butyrate as surrogates of small intestinal bacterial overgrowth in patients with a recent decompensated heart failure.

In patients with heart failure (HF), the exhaled concentrations of hydrogen after a breath test-a non-invasive assessment of small intestinal overgrowth- has been related to HF severity and higher risk of adverse outcomes. Indeed, two intestinal bacterial metabolites-blood Trimethylamine N-Oxide (TMAO) and butyrate-have been related to a worse prognosis in HF. However, the relationship between the exhaled concentrations of hydrogen after a breath test and these two metabolites remains unknown. Thus, in this post-hoc analysis, we sought to evaluate whether these two metabolites are associated with the exhaled concentrations of hydrogen after a breath test in patients with a recent admission for HF. We included 60 patients with a recent hospitalization for HF. Cumulative hydrogen over time was integrated into a single measurement by the area under the concentration curve (AUC-H2). A linear regression multivariable analysis was used to evaluate the associations. A 2-sided p-value < 0.05 was considered to be statistically significant. The median (p25-p75) amino-terminal pro-brain natriuretic peptide, AUC-H2, TMAO, and Butyrate were 4789 pg/ml (1956-11149), 1615 (700-2585), 0.68 (0.42-1.12), and 0.22 ± 13, respectively. After multivariate adjustment, TMAO and butyrate were significantly associated with AUC-H2 (p = 0.027 and p = 0.009, respectively). For TMAO, this association was positive and for butyrate, negative. Bacterial-origin metabolites TMAO and Butyrate were independently related to AUC-H2 in patients with a recent hospitalization for acute HF.

Role of NO-synthases and cyclooxygenases in the hyperreactivity of male rabbit carotid artery to testosterone under experimental diabetes.

Cardiovascular disease is the major cause of morbidity and mortality in diabetic patients, which in turn is also associated with low levels of serum testosterone. The working hypothesis was that diabetes might modify the mechanisms involved in the vascular actions of testosterone in isolated rabbit carotid arteries. Testosterone (10(-8)-3x10(-4)M) induced a concentration-dependent relaxation of precontracted carotid arteries, which was higher in diabetic than in control rabbits. In control rabbits neither endothelium removal nor the nitric oxide synthase (NOS) inhibitor N(G)-nitro-l-arginine (l-NOArg, 10(-5)M) modified the relaxant action of testosterone, and the cyclooxygenase (COX) inhibitor indomethacin (10(-5)M) enhanced this relaxation. In contrast, in diabetic rabbits endothelium removal, l-NOArg (10(-5)M) or indomethacin (10(-5)M) inhibited the testosterone induced relaxation. In arteries from diabetic rabbits, eNOS, iNOS and COX-2 expression and testosterone induced release of prostacyclin resulted enhanced in comparison with arteries from control rabbits. Testosterone (10(-4)M) strongly inhibited CaCl(2) (10(-5)-3x10(-2)M) concentration-related contractions of the carotid artery both in control and diabetic rabbits. These results suggest that testosterone relaxes the rabbit carotid artery by blocking the extracellular calcium entry. Diabetes enhances the vasodilator response of the rabbit carotid artery to testosterone by a mechanism that at least includes an increased modulatory activity of the endothelial nitric oxide and an augmented release of COX-2 vasodilator, prostacyclin rather than the absence of COX-1 vasoconstrictor, thromboxane A(2). The hypotestosteronemia observed in diabetic rabbits could be a consequence of the increased expression of iNOS and could contribute to the hyperreactivity of the rabbit carotid artery to testosterone.

Mechanisms involved in the relaxant action of testosterone in the renal artery from male normoglycemic and diabetic rabbits.

Kidney disease is a frequent complication in diabetes, and significant differences have been reported between male and female patients. Our working hypothesis was that diabetes might modify the vascular actions of testosterone in isolated rabbit renal arteries and the mechanisms involved in these actions. Testosterone (10(-8) to 10(-4)M) induced relaxation of precontracted arteries, without significant differences between control and diabetic rabbits. Both in control and diabetic rabbits endothelium removal inhibited testosterone relaxant action. In arteries with endothelium, incubation with indomethacin (10(-5)M), N(G)-nitro-l-arginine (10(-5)M) or tetraethylammonium (10(-5)M) did not modify relaxations to testosterone neither in control nor in diabetic rabbits. In endothelium-denuded arteries indomethacin enhanced the relaxant action of testosterone, both in control and diabetic rabbits. In arteries from diabetic rabbits, eNOS, iNOS and COX-1 expression and testosterone-induced release of thromboxane A(2) and prostacyclin were not significantly different from those observed in control rabbits. However, COX-2 expression was significantly lower in diabetic rabbits that in control rabbits. In nominally Ca(2+)-free medium, cumulative addition of CaCl2 (10(-5) to 3x10(-2)M) contracted previously depolarized arteries. Testosterone (10(-4)M) inhibited CaCl2 contractions of the renal artery both in control and diabetic rabbits. These results show that testosterone relaxes the renal artery both in control and diabetic rabbits. This relaxation is modulated by muscular thromboxane A(2), it is partially mediated by endothelial prostacyclin, and it involves the blocking of extracellular Ca2+ entry. Diabetes does not modify the mechanisms involved in the relaxant action of testosterone in the rabbit renal artery.

Two-Week Aflibercept or Erlotinib Administration Does Not Induce Changes in Intestinal Morphology in Male Sprague-Dawley Rats But Aflibercept Affects Serum and Urine Metabolic Profiles.

Gastrointestinal toxicity is a frequently observed adverse event during cancer treatment with traditional chemotherapeutics. Currently, traditional chemotherapeutics are often combined with targeted biologic agents. These biologics, however, possess a distinct toxicity profile, and they may also exacerbate the adverse effects of traditional chemotherapeutics. In this study, we aimed to characterize the gastrointestinal and metabolic changes after a 2-week treatment period with aflibercept, an antiangiogenic VEGFR decoy, and with erlotinib, a tyrosine-kinase inhibitor. Male rats were treated either with aflibercept or erlotinib for 2 weeks. During the 2-week treatment period, the animals in the aflibercept group received two subcutaneous doses of 25 mg/kg aflibercept. The erlotinib group got 10 mg/kg of erlotinib by oral gavage every other day. The control groups were treated similarly but received either saline injections or oral gavage of water. Intestinal toxicity was assessed by measuring intestinal permeability and by histological analyses of intestinal tissues. Metabolic changes were measured with 1H nuclear magnetic resonance in serum and urine. Neither aflibercept nor erlotinib induced changes in intestinal permeability or intestinal tissue morphology. However, aflibercept treatment resulted in stunted body weight gain and altered choline, amino acid, and lipid metabolism. Two-week treatment with aflibercept or erlotinib alone does not induce observable changes in gastrointestinal morphology and function. However, observed aflibercept-treatment related metabolic changes suggest alterations in intestinal microbiota, nutrient intake, and adipose tissue function. The metabolic changes are also interesting in respect to the systemic effects of aflibercept and their possible associations with adverse events caused by aflibercept administration.

Diastolic left ventricular function in relation to circulating metabolic biomarkers in a population study.

AIMS: We studied the association of circulating metabolic biomarkers with asymptomatic left ventricular diastolic dysfunction, a risk-carrying condition that affects 25% of the population. METHODS AND RESULTS: In 570 randomly recruited people, we assessed in 2005-2010 and in 2009-2013 the multivariable-adjusted correlations of e' (early left ventricular relaxation) and E/e' (left ventricular filling pressure) measured by Doppler echocardiography with 43 serum metabolites, quantified by magnetic resonance spectroscopy. In 2009-2013, e' cross-sectionally increased (Bonferroni corrected p ≤ 0.016) with the branched-chain amino acid valine (per one standard deviation increment, +0.274 cm/s (95% confidence interval, 0.057-0.491)) and glucose+the amino acid (AA) taurine (+0.258 cm/s (0.067-0.481)), while E/e' decreased ( p ≤ 0.017) with valine (-0.264 (-0.496- -0.031)). The risk of developing left ventricular diastolic dysfunction over follow-up (9.4%) was inversely associated ( p ≤ 0.0059) with baseline glucose+amino acid taurine (odds ratio, 0.64 (0.44-0.94). In partial least squares analyses of all the baseline and follow-up data, markers consistently associated with better diastolic left ventricular function included the amino acids 2-aminobutyrate and 4-hydroxybutyrate and the branched-chain amino acids leucine and valine, and those consistently associated with worse diastolic left ventricular function glucose+amino acid glutamine and fatty acid pentanoate. Branched-chain amino acid metabolism (-log10 p = 12.6) and aminoacyl-tRNA biosynthesis (9.9) were among the top metabolic pathways associated with left ventricular diastolic dysfunction. CONCLUSION: The associations of left ventricular diastolic dysfunction with circulating amino acids and branched-chain amino acids were consistent over a five-year interval and suggested a key role of branched-chain amino acid metabolism and aminoacyl-tRNA biosynthesis in maintaining diastolic left ventricular function.

Diabetes modifies the role of prostanoids and potassium channels which regulate the hypereactivity of the rabbit renal artery to BNP.

Diabetic nephropathy is associated with increased risk of cardiovascular disease. B-type natriuretic peptide (BNP) plays an important role in cardiovascular pathophysiology and therapeutics. The aim of the present study was to investigate the influence of experimental diabetes on the mechanisms that regulate the relaxant response of the rabbit renal artery to BNP. Arterial relaxations to BNP were enhanced in diabetic rabbits. Indomethacin enhanced BNP-induced relaxation in control rabbits but showed no effect in diabetic rabbits. BNP-induced release of thromboxane A2 or prostacyclin was not different in both groups of animals. Iberiotoxin had no effect on relaxations to BNP in both groups of animals. Charybdotoxin displaced to the right the concentration-response curve to BNP in both group of animals, and inhibited BNP-induced relaxation only in diabetic rabbits. Glibenclamide did not modify the BNP-induced relaxations in control rabbits, but inhibited it in diabetic rabbits. These results suggest that diabetes induces hypereactivity of the rabbit renal artery to BNP by mechanisms that at least include (1) a reduced vasoconstrictor influence of arachidonic acid metabolites via cyclooxygenase 2, which is not related with changes in thromboxane A2 and prostacyclin release from the arterial wall and (2) a selectively increased modulatory activity of KATP and endothelial IKCa channels.

Microbiome-metabolome signatures in mice genetically prone to develop dementia, fed a normal or fatty diet.

Cognitive decline, obesity and gut dysfunction or microbial dysbiosis occur in association. Our aim was to identify gut microbiota-metabolomics signatures preceding dementia in genetically prone (3xtg) mice, with and without superimposed high-fat diet. We examined the composition and diversity of their gut microbiota, and serum and faecal metabolites. 3xtg mice showed brain hypometabolism typical of pre-demented stage, and lacked the physiological bacterial diversity between caecum and colon seen in controls. Cluster analyses revealed distinct profiles of microbiota, and serum and fecal metabolome across groups. Elevation in Firmicutes-to-Bacteroidetes abundance, and exclusive presence of Turicibacteraceae, Christensenellaceae, Anaeroplasmataceae and Ruminococcaceae, and lack of Bifidobacteriaceae, were also observed. Metabolome analysis revealed a deficiency in unsaturated fatty acids and choline, and an overabundance in ketone bodies, lactate, amino acids, TMA and TMAO in 3xtg mice, with additive effects of high-fat diet. These metabolic alterations were correlated with high prevalence of Enterococcaceae, Staphylococcus, Roseburia, Coprobacillus and Dorea, and low prevalence of S24.7, rc4.4 and Bifidobacterium, which in turn related to cognitive impairment and cerebral hypometabolism. Our results indicate an effect of transgenic background on gut microbiome-metabolome, enhanced by high-fat diet. The resulting profiles may precede overt cognitive impairment, suggesting their predictive or risk-stratifying potential.

Development and characterization of an experimental model of diet-induced metabolic syndrome in rabbit.

Metabolic syndrome (MetS) has become one of the main concerns for public health because of its link to cardiovascular disease. Murine models have been used to study the effect of MetS on the cardiovascular system, but they have limitations for studying cardiac electrophysiology. In contrast, the rabbit cardiac electrophysiology is similar to human, but a detailed characterization of the different components of MetS in this animal is still needed. Our objective was to develop and characterize a diet-induced experimental model of MetS that allows the study of cardiovascular remodeling and arrhythmogenesis. Male NZW rabbits were assigned to control (n = 15) or MetS group (n = 16), fed during 28 weeks with high-fat, high-sucrose diet. We measured weight, morphological characteristics, blood pressure, glycaemia, standard plasma biochemistry and the metabolomic profile at weeks 14 and 28. Liver histological changes were evaluated using hematoxylin-eosin staining. A mixed model ANOVA or unpaired t-test were used for statistical analysis (P<0.05). Weight, abdominal contour, body mass index, systolic, diastolic and mean arterial pressure increased in the MetS group at weeks 14 and 28. Glucose, triglycerides, LDL, GOT-AST, GOT/GPT, bilirubin and bile acid increased, whereas HDL decreased in the MetS group at weeks 14 and 28. We found a 40% increase in hepatocyte area and lipid vacuoles infiltration in the liver from MetS rabbits. Metabolomic analysis revealed differences in metabolites related to fatty acids, energetic metabolism and microbiota, compounds linked with cardiovascular disease. Administration of high-fat and high-sucrose diet during 28 weeks induced obesity, glucose intolerance, hypertension, non-alcoholic hepatic steatosis and metabolic alterations, thus reproducing the main clinical manifestations of the metabolic syndrome in humans. This experimental model should provide a valuable tool for studies into the mechanisms of cardiovascular problems related to MetS, with special relevance in the study of cardiovascular remodeling, arrhythmias and SCD.

Chemotherapy-induced gastrointestinal toxicity is associated with changes in serum and urine metabolome and fecal microbiota in male Sprague-Dawley rats.

PURPOSE: Chemotherapy-induced gastrointestinal toxicity (CIGT) is a complex process that involves multiple pathophysiological mechanisms. We have previously shown that commonly used chemotherapeutics 5-fluorouracil, oxaliplatin, and irinotecan damage the intestinal mucosa and increase intestinal permeability to iohexol. We hypothesized that CIGT is associated with alterations in fecal microbiota and metabolome. Our aim was to characterize these changes and examine how they relate to the severity of CIGT. METHODS: A total of 48 male Sprague-Dawley rats were injected intraperitoneally either with 5-fluorouracil (150 mg/kg), oxaliplatin (15 mg/kg), or irinotecan (200 mg/kg). Body weight change was measured daily after drug administration and the animals were euthanized after 72 h. Blood, urine, and fecal samples were collected at baseline and at the end of the experiment. The changes in the composition of fecal microbiota were analyzed with 16S rRNA gene sequencing. Metabolic changes in serum and urine metabolome were measured with 1 mm proton nuclear magnetic resonance (1H-NMR). RESULTS: Irinotecan increased the relative abundance of Fusobacteria and Proteobacteria, while 5-FU and oxaliplatin caused only minor changes in the composition of fecal microbiota. All chemotherapeutics increased the levels of serum fatty acids and N(CH3)3 moieties and decreased the levels of Krebs cycle metabolites and free amino acids. CONCLUSIONS: Chemotherapeutic drugs, 5-fluorouracil, oxaliplatin, and irinotecan, induce several microbial and metabolic changes which may play a role in the pathophysiology of CIGT. The observed changes in intestinal permeability, fecal microbiota, and metabolome suggest the activation of inflammatory processes.

Peripheral blood mitochondrial DNA content in relation to circulating metabolites and inflammatory markers: A population study.

Mitochondrial DNA (mtDNA) content might undergo significant changes caused by metabolic derangements, oxidative stress and inflammation that lead to development and progression of cardiovascular diseases. We, therefore, investigated in a general population the association of peripheral blood mtDNA content with circulating metabolites and inflammatory markers. We examined 310 subjects (50.6% women; mean age, 53.3 years) randomly selected from a Flemish population. Relative mtDNA content was measured by quantitative real-time PCR in peripheral blood cells. Peak circulating metabolites were quantified using nuclear magnetic resonance spectroscopy. The level of inflammation was assessed via established inflammatory markers. Using Partial Least Squares analysis, we constructed 3 latent factors from the 44 measured metabolites that explained 62.5% and 8.5% of the variance in the contributing metabolites and the mtDNA content, respectively. With adjustments applied, mtDNA content was positively associated with the first latent factor (P = 0.002). We identified 6 metabolites with a major impact on the construction of this latent factor including HDL3 apolipoproteins, tyrosine, fatty acid with αCH2, creatinine, ß-glucose and valine. We summarized them into a single composite metabolite score. We observed a negative association between the composite metabolic score and mtDNA content (P = 0.001). We also found that mtDNA content was inversely associated with inflammatory markers including hs-CRP, hs-IL6, white blood cell and neutrophil counts as well as neutrophil-to-lymphocyte ratio (P≤0.0024). We demonstrated that in a general population relative peripheral blood mtDNA content was associated with circulating metabolites indicative of perturbed lipid metabolism and with inflammatory biomarkers.

Mechanisms involved in the increased sensitivity of the rabbit basilar artery to atrial natriuretic peptide in diabetes.

Atrial natriuretic peptide (ANP) is a vasodilator with significant regional differences and controversial effects in the cerebral circulation, a vascular bed particularly prone to diabetes-induced complications. The present study has investigated how alloxan-induced diabetes modifies the mechanisms involved in the response of the rabbit basilar artery to ANP. ANP (10-12-10-7M) relaxed precontracted basilar arteries, with higher potency in diabetic than in control rabbits. In arteries from both groups of animals, endothelium removal reduced ANP-induced relaxations. Inhibition of NO-synthesis attenuated ANP-induced relaxation but this attenuation was lower in diabetic than in control rabbits. In control rabbits, indomethacin displaced to the left the concentration-response curve to ANP, without significantly modifying the Emax value. In diabetic rabbits, indomethacin significantly enhanced arterial relaxations to ANP. In KCl-depolarised arteries, relaxation to ANP was almost abolished both in control and in diabetic rabbits. Iberiotoxin inhibited relaxations to ANP in both groups of rabbits. Glibenclamide and 4-aminopyridine inhibited the ANP-induced relaxations more in diabetic than in control rabbits. Basilar arteries from diabetic rabbits showed decreased natriuretic peptide receptor C expression and no changes in natriuretic peptide receptor A, large conductance calcium-activated K+ channels (BKCa), ATP-sensitive K+ channels (KATP) and voltage-sensitive K+ channels (KV) expression. These results suggest that diabetes enhances the sensitivity of the rabbit basilar artery to ANP by mechanisms that at least include reduced expression of natriuretic peptide receptor C, and enhanced activity of KATP and KV channels. Furthermore, diabetes reduces endothelial NO and prostacyclin which mediate arterial relaxation to ANP.

Contribution of endothelin receptors and cyclooxygenase-derivatives to the altered response of the rabbit renal artery to endothelin-1 in diabetes.

The influence of diabetes on regulatory mechanisms and specific receptors implicated in the response of isolated rabbit renal artery to endothelin-1 was examined. Endothelin-1 induced a concentration-dependent contraction that was less potent in arteries from diabetic rabbits than in arteries from control rabbits. Endothelium removal or N(G)-nitro-L-arginine (L-NOARG) enhanced contractions to endothelin-1 either in control and diabetic arteries. Indomethacin inhibited endothelin-1-induced response in control arteries, but enhanced it in diabetic arteries. In contrast to that observed in rubbed and in L-NOARG treated arteries, in the presence of indomethacin the contractile action of endothelin-1 was higher in diabetic arteries than in control arteries. Nimesulide enhanced endothelin-1 contractions both in control and diabetic arteries. Cyclo-(D-Asp-Pro-D-Val-Leu-D-Trp) (BQ-123, endothelin ET(A) receptor antagonist), attenuated endothelin-1 vasoconstriction in control rabbits, while vasoconstriction resulted increased in diabetic rabbits. 2,6-Dimethylpiperidinecarbonyl-gamma-Methyl-Leu-N(in)-(Methoxycarbonyl)-D-Trp-D-Nle (BQ-788, endothelin ET(B) receptor antagonist), enhanced the contractile response in control rabbit arteries without modifying this response in diabetic rabbits. In summary, diabetes decreases the sensitivity of the rabbit renal artery to endothelin-1 by decreasing the ratio between vasoconstrictor and vasodilator prostanoids released after activation of endothelin ET(A) receptors.

Genomic and Metabolomic Profile Associated to Clustering of Cardio-Metabolic Risk Factors.

BACKGROUND: To identify metabolomic and genomic markers associated with the presence of clustering of cardiometabolic risk factors (CMRFs) from a general population. METHODS AND FINDINGS: One thousand five hundred and two subjects, Caucasian, > 18 years, representative of the general population, were included. Blood pressure measurement, anthropometric parameters and metabolic markers were measured. Subjects were grouped according the number of CMRFs (Group 1: <2; Group 2: 2; Group 3: 3 or more CMRFs). Using SNPlex, 1251 SNPs potentially associated to clustering of three or more CMRFs were analyzed. Serum metabolomic profile was assessed by 1H NMR spectra using a Brucker Advance DRX 600 spectrometer. From the total population, 1217 (mean age 54±19, 50.6% men) with high genotyping call rate were analysed. A differential metabolomic profile, which included products from mitochondrial metabolism, extra mitochondrial metabolism, branched amino acids and fatty acid signals were observed among the three groups. The comparison of metabolomic patterns between subjects of Groups 1 to 3 for each of the genotypes associated to those subjects with three or more CMRFs revealed two SNPs, the rs174577_AA of FADS2 gene and the rs3803_TT of GATA2 transcription factor gene, with minimal or no statistically significant differences. Subjects with and without three or more CMRFs who shared the same genotype and metabolomic profile differed in the pattern of CMRFS cluster. Subjects of Group 3 and the AA genotype of the rs174577 had a lower prevalence of hypertension compared to the CC and CT genotype. In contrast, subjects of Group 3 and the TT genotype of the rs3803 polymorphism had a lower prevalence of T2DM, although they were predominantly males and had higher values of plasma creatinine. CONCLUSIONS: The results of the present study add information to the metabolomics profile and to the potential impact of genetic factors on the variants of clustering of cardiometabolic risk factors.