Even chained acylcarnitines predict long-term cardiovascular prognosis in patients with chest pain and non-obstructive coronary artery disease.

Background: Acylcarnitines are essential for mitochondrial fatty acid oxidation. Earlier studies suggest that impaired energy metabolism may be implicated in the pathogenesis of microvascular angina. We explored metabolites from the carnitine pathway as predictors of cardiovascular disease (CVD) - and all-cause mortality among patients with non-obstructive coronary artery disease (NOCAD). Methods: A total of 1046 patients with suspected stable coronary syndrome underwent coronary angiography during 2000-2004, with findings of NOCAD. Serum levels of 8 selected carnitine metabolites were analyzed through liquid chromatography tandem mass spectrometry. Associations with CVD- and all-cause mortality were assessed by multivariable Cox regression models. Results: Median age at inclusion was 57 years. 51.5% were men. During median (25th- 75th percentiles), 14.1 (13.2-15.4) years of follow-up, 5.7% of the participants died from CVD and the incidence of all-cause mortality was 17.3%. Serum acetyl, octanoyl- and palmitoylcarnitine predicted CVD mortality with multivariable HR and 95% CI (per SD increment log transformed) of 1.36 (1.01-1.83), 1.49 (1.15-1.93) and 2.07 (1.49-2.85), p ≤ 0.04, respectively. Higher serum acetyl- and palmitoylcarnitines were also associated with increased risk of all-cause mortality (HR (95% CI): 1.27 (1.01-1.50), and 1.51 (1.26-1.81), p ≤ 0.007. Baseline levels of the precursors trimethyllysine and Æ´-butyrobetaine, carnitine or the odd chained propionylcarnitine and (iso)valerylcarnitine were not associated with adverse outcomes. Conclusion: Elevated serum even-chained acylcarnitines predicted adverse long-term prognosis in NOCAD. The strongest risk estimates were observed for palmitoylcarnitine, which predicted both CVD- and all-cause mortality after extensive multivariable adjustments. Underlying pathomechanisms should be further elucidated.

Rifaximin or Saccharomyces boulardii in heart failure with reduced ejection fraction: Results from the randomized GutHeart trial.

BACKGROUND: The gut microbiota represents a potential treatment target in heart failure (HF) through microbial metabolites such as trimethylamine N-oxide (TMAO) and systemic inflammation. Treatment with the probiotic yeast Saccharomyces boulardii have been suggested to improve left ventricular ejection fraction (LVEF). METHODS: In a multicentre, prospective randomized open label, blinded end-point trial, we randomized patients with LVEF <40% and New York Heart Association functional class II or III, despite optimal medical therapy, to treatment (1:1:1) with the probiotic yeast Saccharomyces boulardii, the antibiotic rifaximin, or standard of care (SoC) only. The primary endpoint, the baseline-adjusted LVEF at three months, was assessed in an intention-to-treat analysis. FINDINGS: We enrolled a total of 151 patients. After three months' treatment, the LVEF did not differ significantly between the SoC arm and the rifaximin arm (mean difference was -1•2 percentage points; 95% CI -3•2 - 0•7; p=0•22) or between the SoC arm and the Saccharomyces boulardii arm (mean difference -0•2 percentage points; 95% CI -2•2 - 1•9; p=0•87). We observed no significant between-group differences in changes in microbiota diversity, TMAO, or C-reactive protein. INTERPRETATION: Three months' treatment with Saccharomyces boulardii or rifaximin on top of SoC had no significant effect on LVEF, microbiota diversity, or the measured biomarkers in our population with HF. FUNDING: The trial was funded by the Norwegian Association for Public Health, the Blix foundation, Stein Erik Hagen's Foundation for Clinical Heart Research, Ada og Hagbart Waages humanitære og veldedige stiftelse, Alfasigma, and Biocodex.

Lipid, fatty acid, carnitine- and choline derivative profiles in rheumatoid arthritis outpatients with different degrees of periodontal inflammation.

Rheumatoid arthritis (RA) and periodontitis are chronic inflammatory diseases with several pathogenic pathways in common. Evidence supports an association between the diseases, but the exact underlying mechanisms behind the connection are still under investigation. Lipid, fatty acid (FA) and metabolic profile alterations have been associated with several chronic inflammatory diseases, including RA and periodontitis. Mitochondria have a central role in regulating cellular bioenergetic and whole-body metabolic homeostasis, and mitochondrial dysfunction has been proposed as a possible link between the two disorders. The aim of this cross-sectional study was to explore whole-blood FA, serum lipid composition, and carnitine- and choline derivatives in 78 RA outpatients with different degrees of periodontal inflammation. The main findings were alterations in lipid, FA, and carnitine- and choline derivative profiles. More specifically, higher total FA and total cholesterol concentrations were found in active RA. Elevated phospholipid concentrations with concomitant lower choline, elevated medium-chain acylcarnitines (MC-AC), and decreased ratios of MC-AC and long-chain (LC)-AC were associated with prednisolone medication. This may indicate an altered mitochondrial function in relation to the increased inflammatory status in RA disease. Our findings may support the need for interdisciplinary collaboration within the field of medicine and dentistry in patient stratification to improve personalized treatment. Longitudinal studies should be conducted to further assess the potential impact of mitochondrial dysfunction on RA and periodontitis.

Nitric oxide in exhaled gas and tetrahydrobiopterin in plasma after exposure to hyperoxia.

The fraction of nitric oxide in exhaled gas (FENO) is decreased after exposure to hyperoxia in vivo, although the mechanisms for this decrease is not clear. A key co-factor for nitric oxide synthase (NOS), tetrahydrobiopterin (BH4), has been shown to be oxidized in vitro when exposed to hyperoxia. We hypothesized that the decrease of FENO is due to decreased enzymatic generation of NO due to oxidation of BH4. The present study was performed to investigate the relationship between levels of FENO and plasma BH4 following hyperoxic exposure in humans. Two groups of healthy subjects were exposed to 100% oxygen for 90 minutes. FENO was measured before and 10 minutes (n = 13) or 60 minutes (n = 14) after the exposure. Blood samples were collected at the same time points for quantification of biopterin levels (BH4, BH2 and B) using LC-MS/MS. Each subject was his or her own control, breathing air for 90 minutes on a separate day. Hyperoxia resulted in a 28.6 % decrease in FENO 10 minutes after exposure (p < 0.001), confirming previous findings. Moreover, hyperoxia also caused a 14.2% decrease in plasma BH4 (p = 0.012). No significant differences were observed in the group measured 60 minutes after exposure. No significant correlation was found between the changes in FENO and BH4 after the hyperoxic exposure (r = 0.052, p = 0.795), this might be due to the recovery of BH4 being faster than the recovery of FENO.

Rosuvastatin alters the genetic composition of the human gut microbiome.

The gut microbiome contributes to the variation of blood lipid levels, and secondary bile acids are associated with the effect of statins. Yet, our knowledge of how statins, one of our most common drug groups, affect the human microbiome is scarce. We aimed to characterize the effect of rosuvastatin on gut microbiome composition and inferred genetic content in stool samples from a randomized controlled trial (n = 66). No taxa were significantly altered by rosuvastatin during the study. However, rosuvastatin-treated participants showed a reduction in the collective genetic potential to transport and metabolize precursors of the pro-atherogenic metabolite trimethylamine-N-oxide (TMAO, p < 0.01), and an increase of related metabolites betaine and γ-butyrobetaine in plasma (p < 0.01). Exploratory analyses in the rosuvastatin group showed that participants with the least favorable treatment response (defined as < median change in high-density/low-density lipoprotein (HDL/LDL) ratio) showed a marked increase in TMAO-levels compared to those with a more favorable response (p < 0.05). Our data suggest that while rosuvastatin has a limited effect on gut microbiome composition, it could exert broader collective effects on the microbiome relevant to their function, providing a rationale for further studies of the influence of statins on the gut microbiome.

Low fibre intake is associated with gut microbiota alterations in chronic heart failure.

AIMS: Recent reports have suggested that patients with heart failure (HF) have an altered gut microbiota composition; however, associations with diet remain largely uninvestigated. We aimed to explore differences in the gut microbiota between patients with HF with reduced ejection fraction and healthy controls, focusing on associations with diet and disease severity. METHODS AND RESULTS: The microbiota composition of two cross-sectional cohorts (discovery, n = 40 and validation, n = 44) of patients with systolic HF and healthy controls (n = 266) was characterized by sequencing of the bacterial 16S rRNA gene. The overall microbial community (beta diversity) differed between patients with HF and healthy controls in both cohorts (P < 0.05). Patients with HF had shifts in the major bacterial phyla, resulting in a lower Firmicutes/Bacteroidetes (F/B) ratio than controls (P = 0.005). Patients reaching a clinical endpoint (listing for heart transplant or death) had lower bacterial richness and lower F/B ratio than controls (P < 0.01). Circulating levels of trimethylamine-N-oxide were associated with meat intake (P = 0.016), but not with gut microbiota alterations in HF. Low bacterial richness and low abundance of several genera in the Firmicutes phylum were associated with low fibre intake. CONCLUSIONS: The gut microbiota in HF was characterized by decreased F/B ratio and reduced bacterial diversity associated with clinical outcome. The gut microbiota alterations in HF were partly related to low fibre intake, emphasizing the importance of diet as a covariate in future studies. Our data could provide a rationale for targeting the gut microbiota in HF with high-fibre diet.

Increased fatty acid oxidation and mitochondrial proliferation in liver are associated with increased plasma kynurenine metabolites and nicotinamide levels in normolipidemic and carnitine-depleted rats.

Dysregulation of the tryptophan (Trp)-NAD+ pathway has been related to several pathological conditions, and the metabolites in this pathway are known to influence mitochondrial respiration and redox status. The aim of this project was to investigate if stimulation of beta-oxidation and mitochondrial proliferation by the mitochondrial-targeted compound 2-(tridec-12-yn-1-ylthio)acetic acid (1-triple TTA) would influence metabolites of the Trp-Kyn-NAD+ pathway. We wished to investigate how carnitine depletion by meldonium-treatment influenced these metabolites. After dietary treatment of male Wistar rats with 1-triple TTA for three weeks, increased hepatic mitochondrial- and peroxisomal fatty acid oxidation resulted. The plasma content of total carnitines decreased compared to control animals, whereas hepatic genes involved in CoA biosynthesis were upregulated by 1-triple TTA treatment. The plasma Trp level and individual metabolites in the kynurenine pathway were increased by 1-triple TTA, associated with decreased hepatic gene expression of indoleamine2,3-dioxygenase. 1-triple TTA treatment increased conversion of Trp to nicotinamide (Nam) as the plasma content of quinolinic acid, Nam and N1-methylnicotinamide (mNam) increased, accompanied with suppression of hepatic gene expression of α-amino-α-carboxymuconate-ε-semialdehyde decarboxylase. A positive correlation between mitochondrial fatty acid oxidation and Trp-derivatives was found. Almost identical results were obtained by 1-triple TTA in the presence of meldonium, which alone exerted minor effects. Moreover, the plasma Kyn:Trp ratio (KTR) correlated negatively to mitochondrial function. Whether increased flux through the Trp-NAD+ pathway increased redox status and lowered inflammation locally and systemically should be considered.

Circulating gut microbiota metabolite trimethylamine N-oxide and oral contraceptive use in polycystic ovary syndrome.

OBJECTIVES: Polycystic ovary syndrome (PCOS) is associated with an increased cardiometabolic risk that might not necessarily translate into adverse cardiovascular outcome later in life. Recently, alterations in gut microbial composition have been reported in the syndrome. Microbiota-dependent metabolite trimethylamine N-oxide (TMAO) and its precursors are closely linked with development of atherosclerotic cardiovascular disease, independently of traditional risk factors. We aimed to assess whether TMAO and its precursors are altered in PCOS and to determine potential impact of treatment on these metabolites. DESIGN: Prospective study. PATIENTS: Twenty-seven overweight/obese patients with PCOS and 25 age- and BMI-matched healthy control women. MEASUREMENTS: At baseline, fasting serum TMAO and its precursors were measured after a 3-day standardized diet. Patients received 3-month OC therapy along with general dietary advice after which all measurements were repeated. RESULTS: Patients had higher total testosterone (T) and free androgen index (FAI) whereas whole-body fat mass, fasting plasma glucose, insulin and lipids were similar between the groups. PCOS group showed significantly higher serum levels of TMAO and its precursors; choline, betaine and carnitine. TMAO and choline showed correlations with T. After 3 months of OC use, TMAO and its precursors significantly decreased along with reductions in BMI, T and FAI. CONCLUSIONS: This study reports for the first time that TMAO and its precursors are elevated in PCOS which might contribute to increased cardiometabolic risk of the syndrome and that short-term OC use along with lifestyle intervention is associated with reduction of these microbiome-dependent metabolites.

Short-Term Activation of Peroxisome Proliferator-Activated Receptors α and γ Induces Tissue-Specific Effects on Lipid Metabolism and Fatty Acid Composition in Male Wistar Rats.

Dietary fatty acids (FAs) affect certain metabolic routes, including pathways controlled by the peroxisome proliferator-activated receptors (PPARs), but tissue-specific effects are not well-defined. Thus, the aim was to compare the metabolic response in hepatic, adipose, and cardiac tissues after treatment with specific PPAR agonists. Male Wistar rats were randomized into three groups: a control group receiving placebo (n=8); a PPARα agonist group receiving WY-14,643 (n=6); and a PPARγ agonist group receiving rosiglitazone (n=6) for 12 days. All animals received a low-fat standard chow diet and were given a daily dose of placebo or agonist orally. Lipids and FA methyl esters were measured in plasma, liver, and heart and gene expression was measured in liver and adipose tissue, while enzyme activities were measured in liver. Treatment with the PPARα agonist was associated with higher liver mass relative to body weight (liver index), lower plasma, and hepatic total cholesterol, as well as lower plasma carnitine and acylcarnitines, compared with control. In heart, PPARα activation leads to overall lower levels of free FAs and specific changes in certain FAs, compared with control. Furthermore, ß-oxidation in liver and the enzymatic activities of well-known PPARα targeted genes were higher following PPARα administration. Overall, rats treated with the PPARα agonist had higher hepatic saturated FAs (SFAs) and monounsaturated FAs (MUFAs) and lower n-6 and n-3 PUFAs, compared to control. Treatment with the PPARγ agonist was associated with a lower liver index, lower plasma triglycerides (TAG) and phospholipids, and higher hepatic phospholipids, compared with control. PPARγ target genes were increased specifically in adipose tissue. Moreover, lower total cardiac FAs and SFA and higher cardiac n-6 PUFA were also associated with PPARγ activation. Altogether, there were characteristic effects of PPARα activation in liver and heart, as well as in plasma. PPARγ effects were not only confined to adipose tissue, but specific effects were also seen in liver, heart, and plasma. In conclusion, short-term treatment with PPAR agonists induced tissue-specific effects on FA composition in liver and heart. Moreover, both PPARα and PPARγ activation lowered plasma TAG and phospholipids, most likely through effects on liver and adipose tissue, respectively. In future studies we aim to reveal whether similar patterns can be found through diet-induced activation of specific pathways.

The carnitine-butyrobetaine-TMAO pathway after cardiac transplant: Impact on cardiac allograft vasculopathy and acute rejection.

BACKGROUND: Alterations in the partly microbiota-dependent carnitine-γ-butyrobetaine (γBB)-trimethylamine N-oxide (TMAO) pathway have been linked to the progression of heart failure and atherosclerotic disease. We evaluated if circulating γBB, TMAO, and their common precursors carnitine and trimethyllysine (TML) were dysregulated after heart transplantation and associated with development of cardiac allograft vasculopathy (CAV) and acute rejection. METHODS: We measured these metabolites in plasma from heart transplant recipients with everolimus-based (n = 32) and standard cyclosporine-based immunosuppression (n = 30) at different time-points and accompanied by assessment of CAV by intravascular ultrasound. RESULTS: Baseline levels of carnitine, TMAO, and TML were elevated in heart transplant recipients compared with controls, and TML remained elevated throughout the observation period. The microbiota-dependent metabolite γBB increased steadily during 3 years of follow-up, with a similar decrease in its endogenous precursor TML. The increase in γBB and the change in TML were associated with a change in total atheroma volume from baseline to 3 years. Increases in γBB and carnitine levels from baseline to 1 year were associated with an increased frequency of acute rejection within the first year after heart transplant. CONCLUSIONS: Our study reveals alterations of the carnitine-γBB-TMAO pathway after heart transplant, with increasing levels of γBB being associated with acute rejection and increase in total atheroma volume during 3 years of follow-up. Future studies should clarify whether interactions between dietary factors, immunosuppressive drugs, and the gut microbiota could influence acute rejection and CAV development to delineate mechanisms and potential novel treatment targets.

Using metabolic profiling and gene expression analyses to explore molecular effects of replacing saturated fat with polyunsaturated fat-a randomized controlled dietary intervention study.

BACKGROUND: Replacing dietary saturated fatty acids (SFAs) with polyunsaturated fatty acids (PUFA) reduces the plasma low-density lipoprotein (LDL) cholesterol and subsequently the risk of cardiovascular disease. However, beyond changes in LDL cholesterol, we lack a complete understanding of the physiologic alterations that occur when improving dietary fat quality. OBJECTIVES: The aim of this study was to gain knowledge of metabolic alterations paralleling improvements in the fat quality of the diet. METHODS: We recently conducted an 8-wk, double-blind, randomized controlled trial replacing SFAs with PUFAs in healthy subjects with moderate hypercholesterolemia (n = 99). In the present substudy, we performed comprehensive metabolic profiling with multiple platforms (both nuclear magnetic resonance- and mass spectrometry-based technology) (n = 99), and analyzed peripheral blood mononuclear cell gene expression (n = 95) by quantitative real-time polymerase chain reaction. RESULTS: A large number of lipoprotein subclasses, myristoylcarnitine and palmitoylcarnitine, and kynurenine were reduced when SFAs were replaced with PUFAs. In contrast, bile acids, proprotein convertase subtilisin/kexin type 9, acetate, and acetoacetate were increased by the intervention. Some amino acids were also altered by the intervention. The mRNA levels of LXRA and LDLR were increased, in addition to several liver X receptor α target genes and genes involved in inflammation, whereas the mRNA levels of UCP2 and PPARD were decreased in peripheral blood mononuclear cells after replacing SFAs with PUFAs. Partial least squares-discriminant analysis showed that the 30 most important variables that contributed to class separation spanned all classes of biomarkers, and was in accordance with the univariate analysis. CONCLUSIONS: Applying metabolomics in randomized controlled dietary intervention trials has the potential to extend our knowledge of the biological and molecular effects of dietary fat quality. This study was registered at clinicaltrials.gov as NCT01679496.

Decrease of tetrahydrobiopterin and NO generation in endothelial cells exposed to simulated diving.

Purpose: Nitric oxide (NO) has been shown to protect against bubble formation and the risk of decompression sickness. We hypothesize that oxidation of tetrahydrobiopterin (BH4) leads to a decreased production of NO during simulated diving. Methods: Human umbilical vein endothelial cells (HUVEC) were exposed to hyperoxia or simulated diving for 24 hours. The levels of biopterins (BH4, BH2 and B) were determined by LC-MS/MS, and the production of NO by monitoring the conversion of L-arginine to L-citrulline. Results: Exposure to hyperoxia decreased BH4 in a dose-dependent manner; by 48 ± 15% following exposure to 40 kPa O2 (P⟨0.001 vs. control at 20 kPa O2), and 70 ± 16% following exposure to 60 kPa O2. Exposure to 40 kPa O2 decreased NO production by 25 ± 9%, but there was no further decrease when increasing oxygen exposure to 60 kPa (25 ± 10%). No additional effects of simulated diving were observed, indicating no additive or synergistic effects of hyperbaria and hyperoxia on the BH4 level or NO generation. Conclusion: NO generation in intact human endothelial cells was decreased by simulated diving, as well as by hyperoxic exposure, while BH4 levels seem to be affected only by hyperoxia. Hence, the results suggest that BH4 is not the sole determinant of NO generation in HUVEC.

A fatty acid analogue targeting mitochondria exerts a plasma triacylglycerol lowering effect in rats with impaired carnitine biosynthesis.

L-carnitine is important for the catabolism of long-chain fatty acids in the mitochondria. We investigated how the triacylglycerol (TAG)-lowering drug 2-(tridec-12-yn-1-ylthio)acetic acid (1-triple TTA) influenced lipid metabolism in carnitine-depleted, 3-(2,2,2-trimethylhydrazinium)propionate dehydrate (Mildronate; meldonium)-treated male Wistar rats. As indicated, carnitine biosynthesis was impaired by Mildronate. However, TAG levels of both plasma and liver were decreased by 1-triple TTA in Mildronate-treated animals. This was accompanied by increased gene expression of proteins involved in mitochondrial activity and proliferation and reduced mRNA levels of Dgat2, ApoB and ApoCIII in liver. The hepatic energy state was reduced in the group of Mildronate and 1-triple TTA as reflected by increased AMP/ATP ratio, reduced energy charge and induced gene expression of uncoupling proteins 2 and 3. The increase in mitochondrial fatty acid oxidation was observed despite low plasma carnitine levels, and was linked to strongly induced gene expression of carnitine acetyltransferase, translocase and carnitine transporter, suggesting an efficient carnitine turnover. The present data suggest that the plasma TAG-lowering effect of 1-triple TTA in Mildronate-treated rats is not only due to increased mitochondrial fatty acid oxidation reflected by increased mitochondrial biogenesis, but also to changes in plasma clearance and reduced TAG biosynthesis.

Associations between fatty acid oxidation, hepatic mitochondrial function, and plasma acylcarnitine levels in mice.

BACKGROUND: The 4-thia fatty acid tetradecylthiopropionic acid (TTP) is known to inhibit mitochondrial ß-oxidation, and can be used as chemically induced hepatic steatosis-model in rodents, while 3-thia fatty acid tetradecylthioacetic acid (TTA) stimulates fatty acid oxidation through activation of peroxisome proliferator activated receptor alpha (PPARα). We wished to determine how these two compounds affected in vivo respiration and mitochondrial efficiency, with an additional goal to elucidate whether mitochondrial function is reflected in plasma acylcarnitine levels. METHODS: C57BL/6 mice were divided in 4 groups of 10 mice and fed a control low-fat diet, low-fat diets with 0.4% (w/w) TTP, 0.4% TTA or a combination of these two fatty acids for three weeks (n = 10). At sacrifice, ß-oxidation and oxidative phosphorylation (OXPHOS) capacity was analysed in fresh liver samples. Hepatic mitochondria were studied using transmission electron microscopy. Lipid classes were measured in plasma, heart and liver, acylcarnitines were measured in plasma, and gene expression was measured in liver. RESULTS: The TTP diet resulted in hepatic lipid accumulation, plasma L-carnitine and acetylcarnitine depletion and elevated palmitoylcarnitine and non-esterified fatty acid levels. No significant lipid accumulation was observed in heart. The TTA supplement resulted in enhanced hepatic ß-oxidation, accompanied by an increased level of acetylcarnitine and palmitoylcarnitine in plasma. Analysis of mitochondrial respiration showed that TTP reduced oxidative phosphorylation, while TTA increased the maximum respiratory capacity of the electron transport system. Combined treatment with TTP and TTA resulted in a profound stimulation of genes involved in the PPAR-response and L-carnitine metabolism, and partly prevented triacylglycerol accumulation in the liver concomitant with increased peroxisomal ß-oxidation and depletion of plasma acetylcarnitines. Despite an increased number of mitochondria in the liver of TTA + TTP fed mice, the OXPHOS capacity was significantly reduced. CONCLUSION: This study indicates that fatty acid ß-oxidation directly affects mitochondrial respiratory capacity in liver. As plasma acylcarnitines reflected the reduced mitochondrial ß-oxidation in TTP-fed mice, they could be useful tools to monitor mitochondrial function. As mitochondrial dysfunction is a major determinant of metabolic disease, this supports their use as plasma markers of cardiovascular risk in humans. Results however indicate that high PPAR activation obscures the interpretation of plasma acylcarnitine levels.

Serum Carnitine Metabolites and Incident Type 2 Diabetes Mellitus in Patients With Suspected Stable Angina Pectoris.

Context: Carnitine and its metabolites are centrally involved in fatty acid metabolism. Although elevated circulating concentrations have been observed in obesity and insulin resistance, prospective studies examining whether these metabolites are associated with incident type 2 diabetes mellitus (T2D) are sparse. Objective: We performed a comprehensive evaluation of metabolites along the carnitine pathway relative to incident T2D. Design: A total of 2519 patients (73.1% men) with coronary artery disease, but without T2D, were followed for median 7.7 years until the end of 2009, during which 173 (6.9%) new cases of T2D were identified. Serum levels of free carnitine, its precursors trimethyllysine (TML) and γ-butyrobetaine, and the esters acetyl-, propionyl-, (iso)valeryl-, octanoyl-, and palmitoylcarnitine were measured by liquid chromatography/tandem mass spectrometry. Risk associations were explored by logistic regression and reported per (log-transformed) standard deviation increment. Results: Median age at inclusion was 62 years and median body mass index (BMI) 26.0 kg/m2. In models adjusted for age, sex, fasting status, BMI, estimated glomerular filtration rate, glycated hemoglobin A1c, triglyceride and high-density lipoprotein cholesterol levels, and study center, serum levels of TML and palmitoylcarnitine associated positively [odds ratio (95% confidence interval), 1.22 (1.04 to 1.43) and 1.24 (1.04 to 1.49), respectively], whereas γ-butyrobetaine associated negatively [odds ratio (95% confidence interval) 0.81 (0.66 to 0.98)] with T2D risk. Conclusion: Serum levels of TML, γ-butyrobetaine, and the long-chained palmitoylcarnitine predict long-term risk of T2D independently of traditional risk factors, possibly reflecting dysfunctional fatty acid metabolism in patients susceptible to T2D development.

Elevated trimethylamine-N-oxide (TMAO) is associated with poor prognosis in primary sclerosing cholangitis patients with normal liver function.

BACKGROUND: Trimethylamine-N-oxide (TMAO) is produced in the liver from trimethylamine, which is exclusively generated by gut bacteria. OBJECTIVE: The objective of this article is to investigate the relationship between TMAO and primary sclerosing cholangitis (PSC) and its clinical characteristics. METHODS: Serum TMAO was measured in 305 PSC patients, 90 ulcerative colitis patients and 99 healthy controls. RESULTS: In PSC patients with normal liver function (n = 197), TMAO was higher in patients reaching liver transplantation or death during follow-up than those who did not, with an optimal TMAO cut-off of 4.1 µM (AUC = 0.64, p < 0.001). PSC patients with high TMAO (>4.1 µM, n = 77) exhibited shorter transplantation-free survival than patients with low TMAO (n = 120, log-rank test: p < 0.0001). High TMAO (>4.1 µM) was associated with reduced transplantation-free survival (HR 1.87, p = 0.011), independently of the Mayo risk score (HR 1.74, p < 0.001). Overall, PSC patients demonstrated reduced TMAO values compared with ulcerative colitis and healthy controls, mainly caused by PSC patients with reduced liver function (INR > 1.2), suggesting impaired oxidation of trimethylamine to TMAO. PSC patients with and without inflammatory bowel disease had similar TMAO levels. CONCLUSION: In PSC patients with normal liver function, elevated TMAO was associated with shorter transplantation-free survival, potentially reflecting clinically relevant metabolic changes resulting from dietary interactions with the gut microbiota.

Increased hepatic mitochondrial FA oxidation reduces plasma and liver TG levels and is associated with regulation of UCPs and APOC-III in rats.

Hepatic mitochondrial function, APOC-III, and LPL are potential targets for triglyceride (TG)-lowering drugs. After 3 weeks of dietary treatment with the compound 2-(tridec-12-yn-1-ylthio)acetic acid (1-triple TTA), the hepatic mitochondrial FA oxidation increased more than 5-fold in male Wistar rats. Gene expression analysis in liver showed significant downregulation of APOC-III and upregulation of LPL and the VLDL receptor. This led to lower hepatic (53%) and plasma (73%) TG levels. Concomitantly, liver-specific biomarkers related to mitochondrial biogenesis and function (mitochondrial DNA, citrate synthase activity, and cytochrome c and TFAM gene expression) were elevated. Interestingly, 1-triple TTA lowered plasma acetylcarnitine levels, whereas the concentration of ß-hydroxybutyrate was increased. The hepatic energy state was reduced in 1-triple TTA-treated rats, as reflected by increased AMP/ATP and decreased ATP/ADP ratios, whereas the energy state remained unchanged in muscle and heart. The 1-triple TTA administration induced gene expression of uncoupling protein (UCP)2 and UCP3 in liver. In conclusion, the 1-triple TTA-mediated clearance of blood TG may result from lowered APOC-III production, increased hepatic LPL gene expression, mitochondrial FA oxidation, and (re)uptake of VLDL facilitating drainage of FAs to the liver for ß-oxidation and production of ketone bodies as extrahepatic fuel. The possibility that UCP2 and UCP3 mediate a moderate degree of mitochondrial uncoupling should be considered.

HIV-infected persons with type 2 diabetes show evidence of endothelial dysfunction and increased inflammation.

BACKGROUND: Increased incidence of cardiovascular diseases (CVD) in both HIV infection and type 2 diabetes (T2D) compared to the general population has been described. Little is known about the combined effect of HIV infection and T2D on inflammation and endothelial function, both of which may contribute to elevated risk of CVD. METHODS: Cross-sectional study including 50 HIV-infected persons on combination anti-retroviral therapy (cART), with HIV RNA <200 copies/mL (n = 25 with T2D (HIV + T2D+), n = 25 without T2D (HIV + T2D-)) and 50 uninfected persons (n = 22 with T2D (HIV-T2D+) and n = 28 without T2D (HIV-T2D-)). Groups were matched on age and sex. High sensitive C-reactive protein (hsCRP) was used to determine inflammation (cut-off 3 mg/L). The marker of endothelial dysfunction asymmetric dimethylarginine (ADMA) was measured using high performance liquid chromatography. Trimethylamine-N-oxide (TMAO), a microbiota-dependent, pro-atherogenic marker was measured using stable isotope dilution LC/MS/MS. RESULTS: The percentage of HIV + T2D+, HIV + T2D-, HIV-T2D+, and HIV-T2D- with hsCRP above cut-off was 50%, 19%, 47%, and 11%, respectively. HIV + T2D+ had elevated ADMA (0.67 µM (0.63-0.72) compared to HIV + T2D- (0.60 µM (0.57-0.64) p = 0.017), HIV-T2D+ (0.57 µM (0.51-63) p = 0.008), and HIV-T2D- (0.55 µM (0.52-0.58) p < 0.001). No differences in TMAO between groups were found. However, a positive correlation between ADMA and TMAO was found in the total population (rs = 0.32, p = 0.001), which was mainly driven by a close correlation in HIV + T2D+ (rs = 0.63, p = 0.001). CONCLUSION: Elevated inflammation and evidence of endothelial dysfunction was found in HIV-infected persons with T2D. The effect on inflammation was mainly driven by T2D, while both HIV infection and T2D may contribute to endothelial dysfunction. Whether gut microbiota is a contributing factor to this remains to be determined.

Serum Acylcarnitines and Risk of Cardiovascular Death and Acute Myocardial Infarction in Patients With Stable Angina Pectoris.

BACKGROUND: Excess levels of serum acylcarnitines, which are intermediate products in metabolism, have been observed in metabolic diseases such as type 2 diabetes mellitus. However, it is not known whether acylcarnitines may prospectively predict risk of cardiovascular death or acute myocardial infarction in patients with stable angina pectoris. METHODS AND RESULTS: This study included 4164 patients (median age, 62 years; 72% men). Baseline serum acetyl-, octanoyl-, palmitoyl-, propionyl-, and (iso)valerylcarnitine were measured using liquid chromatography/tandem mass spectrometry. Hazard ratios (HRs) and 95% CIs for quartile 4 versus quartile 1 are reported. The multivariable model included age, sex, body mass index, fasting status, current smoking, diabetes mellitus, apolipoprotein A1, apolipoprotein B, creatinine, left ventricular ejection fraction, extent of coronary artery disease, study center, and intervention with folic acid or vitamin B6. During median 10.2 years of follow-up, 10.0% of the patients died of cardiovascular disease and 12.8% suffered a fatal or nonfatal acute myocardial infarction. Higher levels of the even-chained acetyl-, octanoyl-, and palmitoyl-carnitines were significantly associated with elevated risk of cardiovascular death, also after multivariable adjustments (HR [95% CI]: 1.52 [1.12, 2.06]; P=0.007; 1.73 [1.23, 2.44]; P=0.002; and 1.61 [1.18, 2.21]; P=0.003, respectively), whereas their associations with acute myocardial infarction were less consistent. CONCLUSIONS: Among patients with suspected stable angina pectoris, elevated serum even-chained acylcarnitines were associated with increased risk of cardiovascular death and, to a lesser degree with acute myocardial infarction, independent of traditional risk factors. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT00354081.

Neil3-dependent base excision repair regulates lipid metabolism and prevents atherosclerosis in Apoe-deficient mice.

Increasing evidence suggests that oxidative DNA damage accumulates in atherosclerosis. Recently, we showed that a genetic variant in the human DNA repair enzyme NEIL3 was associated with increased risk of myocardial infarction. Here, we explored the role of Neil3/NEIL3 in atherogenesis by both clinical and experimental approaches. Human carotid plaques revealed increased NEIL3 mRNA expression which significantly correlated with mRNA levels of the macrophage marker CD68. Apoe(-/-)Neil3(-/-) mice on high-fat diet showed accelerated plaque formation as compared to Apoe(-/-) mice, reflecting an atherogenic lipid profile, increased hepatic triglyceride levels and attenuated macrophage cholesterol efflux capacity. Apoe(-/-)Neil3(-/-) mice showed marked alterations in several pathways affecting hepatic lipid metabolism, but no genotypic alterations in genome integrity or genome-wide accumulation of oxidative DNA damage. These results suggest a novel role for the DNA glycosylase Neil3 in atherogenesis in balancing lipid metabolism and macrophage function, potentially independently of genome-wide canonical base excision repair of oxidative DNA damage.