Effect of glycine on the cyclooxygenase pathway of the kidney arachidonic acid metabolism in a rat model of metabolic syndrome

Profile of plasma free amino acids, carnitine and acylcarnitines, and JAK2v617f mutation as potential metabolic markers in children with type 1 diabetic nephropathy

Fifty diabetic nephropathy (DN) children with type 1 diabetes mellitus (T1DM) and 50 healthy matched controls were included. Chromatographic assays of 14 amino acids, free carnitine and 27 carnitine esters using high-performance liquid chromatography/electrospray ionization-mass spectroscopy, and genetic testing for JAK2v617f mutation using real-time PCR were performed. Patients had significantly lower levels of tyrosine, branched-chain amino acids (BCAAs), and BCAA/AAA (aromatic chain amino acids) ratios, glycine, arginine, ornithine, free carnitine and some carnitine esters (C5, 6, 12 and 16) and higher phenylalanine, phenylalanine/tyrosine ratio and C18 compared with the controls and in the macro-albuminuria vs. the microalbuminuria group (p < 0.05 for all) except for free carnitine. Plasma carnitine was negatively correlated with eGFR (r = -0.488, p = 0.000). There were significant positive correlations between tyrosine with UACR ratio (r = 0.296, p = 0.037). The plasma BCAA/AAA ratio showed significant negative correlations with UACR (r = -0.484, p = 0.000). There was a significantly higher frequency of the JAK2V617F gene mutation in diabetic nephropathy patients compared with the control group and in macro-albuminuria than the microalbuminuria group (p = 0.000) for both. When monitoring children with T1DM, plasma free amino acids and acylcarnitine profiles should be considered, especially if they have tested positive for JAK2V617F for the early diagnosis of DN.

Effects of soda water on blood lipid and metabolic profiling of urine in hyperlipidemia rats using UPLC/Triple-TOF MS

The effects of a natural soda water (Shi Han Quan, SHQ) on hyperlipidemia and the changes of urine metabolic profiling by metabolomics techniques were investigate. Thirty six Wistar rats weighing 160-200 g were divided into control group, hyperlipidemia (HL) group, and hyperlipidemia + SHQ water (SHQ) group. The metabolites in urine were determined using ultra high performance liquid chromatography-triple-time of flight-mass spectrometry (UPLC/Triple-TOF MS). At the end of 1 month and 3 months, the total glyceride (TG) level was significantly lower in SHQ group compared to HL group. There was no significantly difference in total cholesterol (TC) levels in HL group compared with SHQ group. The results showed that dinking SHQ water can improve the TG, but with no effects on TC. After drinking SHQ water for 3 months, the rats in different groups could be classified into different clusters according to the metabolites in urine. Total 15 important metabolites were found and correlated with disturbance of amino acid, phospholipid, fatty acid and vitamin metabolism, which suggested the changes of metabolism in the body and possible mechanism by which SHQ improved the TG. These findings provide a new insight for the prevention and control of hyperlipidemia.

Effect of Hibiscus sabdariffa L. on the Metabolism of Arachidonic Acid in the Isolated Kidney of a Rat Model of Metabolic Syndrome

The renal system is engaged in metabolic syndrome (MS) and metabolites of arachidonic acid (AA) participate in renal homeostasis and disruption of functionality. Hibiscus sabdariffa L (HSL) is used as a diuretic and could improve renal function. The aim of this study was to assess if treatment with HSL at 2% improves renal function in MS through the metabolites of AA. A total of 24 male Wistar rats were divided into four groups: Group 1, control (C); Group 2, MS with 30% sucrose in drinking water, Group 3, MS plus HSL infusion at 2% (MS+HSL); and Group 4, C+HSL. We evaluated the perfusion pressure changes (∆-PP), the activities of cyclooxygenases (COXs), the percentage of AA, the expressions of PLA2, COX2, COX1, 5-LOX, TAXS and CYP450, and the concentrations of prostaglandins in the kidney from rats with MS. There was a decrease in the ∆-PP, in the activities of COXs, and the expressions of COX2 and CYP450 (p ≤ 0.03, respectively)as well asPGE2, TxB2, and LKB4 (p ≤ 0.01, respectively). However, the percentage of AA and expressions of PLA2 and PGE1 (p = 0.01, respectively) were increased in C and MS+HSL. The HSL treatment improved the function and anatomical structure of the kidneys in the MS rats, through antioxidant molecules, and inhibited the pathways that metabolize the AA including that of PLA2, COX2, 5-LOX, TAXS, and CYP450 while favoring the COX1 pathway. This improves the vascular resistance of renal arterioles.

Integrated metagenomics and metabolomics analysis illustrates the systemic impact of the gut microbiota on host metabolism after bariatric surgery

AIM

To explore how bariatric surgery (BS) modified the obesity-associated gut microbiome, the host metabolome, and their interactions in obese Korean patients.

MATERIALS AND METHODS

Stool and fasting blood samples were obtained before and 1, 3, 6, and 12 months after BS from 52 patients enrolled in the Korean Obesity Surgical Treatment Study. We analysed the gut microbiome by 16S rRNA gene sequencing and the serum metabolome, including bile acids, by nuclear magnetic resonance spectroscopy and ultrahigh-performance liquid chromatography/triple quadrupole mass spectrometry.

RESULTS

Stool metagenomics showed that 27 microbiota were enriched and 14 microbiota were reduced after BS, whereas the abundances and diversity of observed features were increased. The levels of branched-chain amino acids and metabolites of energy metabolism in serum were decreased after surgery, whereas the levels of metabolites related to microbial metabolism, including dimethyl sulphone, glycine, and secondary bile acids, were increased in the serum samples. In addition, we found notable mutual associations among metabolites and gut microbiome changes attributed to BS.

CONCLUSIONS

Changes in the gut microbiome community and systemic levels of amino acids and sugars were directly derived from anatomical changes in the gastrointestinal tract after BS. We hypothesized that the observed increases in microbiome-related serum metabolites were a result of complex and indirect changes derived from BS. Ethnic-specific environmental or genetic factors could affect Korean-specific postmetabolic modification in obese patients who undergo BS.

Advanced Research of Abdominal Aortic Aneurysms on Metabolism

Abdominal aortic aneurysm (AAA) is a cardiovascular disease with a high risk of death, seriously threatening the life and health of people. The specific pathogenesis of AAA is still not fully understood. In recent years, researchers have found that amino acid, lipid, and carbohydrate metabolism disorders play important roles in the occurrence and development of AAA. This review is aimed to summarize the latest research progress of the relationship between AAA progression and body metabolism. The body metabolism is closely related to the occurrence and development of AAA. It is necessary to further investigate the pathogenesis of AAA from the perspective of metabolism to provide theoretical basis for AAA diagnosis and drug development.

Serum and urine metabolomics reveal potential biomarkers of T2DM patients with nephropathy

Background

Diabetes is a metabolic disease and is often accompanied by severe microvascular and macrovascular complications. A comprehensive understanding of its complex mechanisms can help prevent type 2 diabetes mellitus (T2DM) complications, such as diabetic nephropathy (DN).

Methods

To reveal the systemic metabolic changes related to renal injury, clinical information of T2DM patients with or without nephropathy was collected, and it was found that serum urea levels of DN patients were significantly higher in T2DM patients without nephropathy. Further along the disease progression, the serum urea levels also gradually increased. We used gas chromatograph coupled with time-of-flight mass spectrometry (GC-TOFMS) metabolomics to analyze the serum and urine metabolites of T2DM patients with or without nephropathy to study the metabolic changes associated with the disease.

Results

Finally, we identified 61 serum metabolites and 46 urine metabolites as potential biomarkers related to DN (P<0.05, VIP >1). In order to determine which metabolic pathways were major altered in DN, we summarized pathway analysis based on P values from their impact values and enrichment. There were 9 serum metabolic pathways and 12 urine metabolic pathways with significant differences in serum and urine metabolism, respectively.

Conclusions

This study emphasizes that GC-TOFMS-based metabolomics provides insight into the potential pathways in the pathogenesis and progression of DN.

Sarcosine promotes trafficking of dendritic cells and improves efficacy of anti-tumor dendritic cell vaccines via CXC chemokine family signaling

Background

Dendritic cell (DC) vaccine efficacy is directly related to the efficiency of DC migration to the lymph node after delivery to the patient. We discovered that a naturally occurring metabolite, sarcosine, increases DC migration in human and murine cells resulting in significantly improved anti-tumor efficacy. We hypothesized that sarcosine induced cell migration was due to chemokine signaling.

Methods

DCs were harvested from the bone marrow of wild type C57BL/6 mice and electroporated with tumor messenger RNA (mRNA). Human DCs were isolated from peripheral blood mononuclear cells (PBMCs). DCs were treated with 20 mM of sarcosine. Antigen specific T cells were isolated from transgenic mice and injected intravenously into tumor bearing mice. DC vaccines were delivered via intradermal injection. In vivo migration was evaluated by flow cytometry and immunofluorescence microscopy. Gene expression in RNA was investigated in DCs via RT-PCR and Nanostring.

Results

Sarcosine significantly increased human and murine DC migration in vitro. In vivo sarcosine-treated DCs had significantly increased migration to both the lymph nodes and spleens after intradermal delivery in mice. Sarcosine-treated DC vaccines resulted in significantly improved tumor control in a B16F10-OVA tumor flank model and improved survival in an intracranial GL261-gp100 glioma model. Gene expression demonstrated an upregulation of CXCR2, CXCL3 and CXCL1 in sarcosine- treated DCs. Further metabolic analysis demonstrated the up-regulation of cyclooxygenase-1 and Pik3cg. Sarcosine induced migration was abrogated by adding the CXCR2 neutralizing antibody in both human and murine DCs. CXCR2 neutralizing antibody also removed the survival benefit of sarcosine-treated DCs in the tumor models.

Conclusion

Sarcosine increases the migration of murine and human DCs via the CXC chemokine pathway. This platform can be utilized to improve existing DC vaccine strategies.

Glycine increases glyoxalase-1 function by promoting nuclear factor erythroid 2-related factor 2 translocation into the nucleus of kidney cells of streptozotocin-induced diabetic rats

AIMS/INTRODUCTION

We have previously reported that glycine suppresses the advanced glycation end-products signaling pathway and mitigates subsequent oxidative stress in the kidneys of diabetic rats. In the present study, we investigated whether this beneficial effect was associated with upregulation of glyoxalase-1 (Glo1) and activation of the nuclear factor erythroid 2-related factor 2 (Nrf2).

MATERIALS AND METHODS

Both healthy rats and streptozotocin-induced diabetic rats were administrated with glycine (1% added to the drinking water) for 12 weeks. The function of Glo1, messenger ribonucleic acid (mRNA) and protein expressions of Nrf2, and markers of oxidative status were measured in the kidneys. The mRNA expressions of other downstream signaling molecules of the Nrf2 pathway were also determined.

RESULTS

The mRNA and protein expressions, as well as the activity of Glo1, were decreased in the kidneys of diabetic rats, accompanied by diminished glutathione levels. After glycine treatment, these parameters of Glo1 function were markedly increased. Compared with the control group, the levels of Nrf2 mRNA and protein in the total kidney lysis were both markedly elevated in the diabetic group and glycine-treated group. However, the nuclear translocation of Nrf2 was significantly increased in the glycine-treated group than in the diabetic group. In addition, the anti-oxidant capacity and the expressions of other downstream molecules of the Nrf2 signaling pathway were significantly increased after glycine treatment.

CONCLUSIONS

The present study shows that glycine might enhance the function of Glo1 and restore anti-oxidant defense by promoting the nuclear translocation of Nrf2, thus inhibiting advanced glycation end-products formation and protecting against renal oxidative stress.

Glycine promotes longevity in Caenorhabditis elegans in a methionine cycle-dependent fashion

The deregulation of metabolism is a hallmark of aging. As such, changes in the expression of metabolic genes and the profiles of amino acid levels are features associated with aging animals. We previously reported that the levels of most amino acids decline with age in Caenorhabditis elegans (C. elegans). Glycine, in contrast, substantially accumulates in aging C. elegans. In this study we show that this is coupled to a decrease in gene expression of enzymes important for glycine catabolism. We further show that supplementation of glycine significantly prolongs C. elegans lifespan, and early adulthood is important for its salutary effects. Moreover, supplementation of glycine ameliorates specific transcriptional changes that are associated with aging. Glycine feeds into the methionine cycle. We find that mutations in components of this cycle, methionine synthase (metr-1) and S-adenosylmethionine synthetase (sams-1), completely abrogate glycine-induced lifespan extension. Strikingly, the beneficial effects of glycine supplementation are conserved when we supplement with serine, which also feeds into the methionine cycle. RNA-sequencing reveals a similar transcriptional landscape in serine- and glycine-supplemented worms both demarked by widespread gene repression. Taken together, these data uncover a novel role of glycine in the deceleration of aging through its function in the methionine cycle.

Roux-en-Y gastric bypass surgery alters serum metabolites and fatty acids in patients with morbid obesity

AIM

Bariatric surgery induces significant weight loss, increases insulin sensitivity, and reduces mortality, but the underlying mechanisms are not clear. It was hypothesized that Roux-en-Y gastric bypass (RYGB) surgery improves metabolic profile along with weight loss. The objective of this pilot study was to evaluate changes in serum metabolites and fatty acids (FA) at 2 weeks and 6 months after RYGB.

MATERIALS AND METHODS

Serum samples were collected pre-surgery, at 2 weeks and 6 months post-surgery from 20 patients undergoing RYGB surgery. Serum non-esterified free FA (NEFA) were measured. Serum metabolites and FA were measured using nuclear magnetic resonance spectroscopy and improved direct fatty acid methyl ester synthesis and the gas chromatography/mass spectrometry method, respectively, in subjects who completed follow-up at 6 months (n = 8).

RESULTS

Mean (standard deviation) percent total weight loss was 6.70% (1.7) and 24.91% (6.63) at 2 weeks (n = 15) and 6 months (n = 8) post-surgery, respectively. NEFA were significantly reduced at 6 months post-surgery (P = 0.001, n = 8). Serum branched chain amino acids, 2-aminobutyrate, butyrate, 2-hydroxybutyrate, 3-hydroxybutyrate, acetone, 2-methylglutarate, and 2-oxoisocaproate were significantly reduced, while serum alanine, glycine, pyruvate, and taurine were significantly elevated at 6 months post-surgery compared with pre-surgery (n = 8, P < 0.05). Also, serum FA C10:0, C13:0, C14:0, C15:0, and C18:0 increased significantly (n = 8, P < 0.05) by 6 months post-surgery.

CONCLUSIONS

Changes in serum metabolites and FA at 6 months post-RYGB surgery in this pilot study with limited number of participants are suggestive of metabolic improvement; larger studies are warranted for confirmation.

Nutritional epigenetics with a focus on amino acids: implications for the development and treatment of metabolic syndrome

Recent findings from human and animal studies indicate that maternal undernutrition or overnutrition affects covalent modifications of the fetal genome and its associated histones that can be carried forward to subsequent generations. An adverse outcome of maternal malnutrition is the development of metabolic syndrome, which is defined as a cluster of disorders including obesity, hyperglycemia, hyperinsulinemia, hyperlipidemia, hypertension and insulin resistance. The transgenerational impacts of maternal nutrition are known as fetal programming, which is mediated by stable and heritable alterations of gene expression through covalent modifications of DNA and histones without changes in DNA sequences (namely, epigenetics). The underlying mechanisms include chromatin remodeling, DNA methylation (occurring at the 5'-position of cytosine residues within CpG dinucleotides), histone modifications (acetylation, methylation, phosphorylation, ubiquitination and sumoylation) and expression and activity of small noncoding RNAs. The enzymes catalyzing these reactions include S-adenosylmethionine-dependent DNA and protein methyltransferases, DNA demethylases, histone acetylase (lysine acetyltransferase), general control nonderepressible 5 (GCN5)-related N-acetyltransferase (a superfamily of acetyltransferase) and histone deacetylase. Amino acids (e.g., glycine, histidine, methionine and serine) and vitamins (B6, B12 and folate) play key roles in provision of methyl donors for DNA and protein methylation. Therefore, these nutrients and related metabolic pathways are of interest in dietary treatment of metabolic syndrome. Intervention strategies include targeting epigenetically disturbed metabolic pathways through dietary supplementation with nutrients (particularly functional amino acids and vitamins) to regulate one-carbon-unit metabolism, antioxidative reactions and gene expression, as well as protein methylation and acetylation. These mechanism-based approaches may effectively improve health and well-being of affected offspring.

Vascular endothelial function is improved by oral glycine treatment in aged rats

Glycine has been used to reduce oxidative stress and proinflammatory mediators in some metabolic disorders; however, its effect on the vasculature has been poorly studied. The aim of this work was to explore the effect of glycine on endothelial dysfunction in aged rats. Aortic rings with intact or denuded endothelium were obtained from untreated or glycine-treated male Sprague-Dawley rats at 5 and 15 months of age. Concentration-response curves to phenylephrine (PHE) were obtained from aortic rings incubated with N(G)-nitro-l-arginine methyl ester (l-NAME), superoxide dismutase (SOD), indomethacin, SC-560, and NS-398. Aortic mRNA expression of endothelial nitric oxide synthase (eNOS), NADPH oxidase 4 (NOX-4), cyclooxygenase 1 (COX-1), cyclooxygenase 2 (COX-2), tumour necrosis factor (TNF)-α, and interleukin-1 β was measured by real time RT-PCR. The endothelial modulation of the contraction by PHE was decreased in aortic rings from aged rats. Glycine treatment improved this modulator effect and increased relaxation to acetylcholine. Glycine augmented the sensitivity for PHE in the presence of l-NAME and SOD. It also reduced the contraction by incubation with indomethacin, SC-560, and NS-398. Glycine increased the mRNA expression of eNOS and decreased the expression of COX-2 and TNF-α. Glycine improved the endothelium function in aged rats possibly by enhancing eNOS expression and reducing the role of superoxide anion and contractile prostanoids that increase the nitric oxide bioavailability.

Hydrolyzed tilapia fish collagen modulates the biological behavior of macrophages under inflammatory conditions

This is the first study showing that HFC can inhibit the excessive production of inflammatory mediators in RAW264.7 macrophages.

17β Estradiol Modulates Perfusion Pressure and Expression of 5-LOX and CYP450 4A in the Isolated Kidney of Metabolic Syndrome Female Rats

Prevalence of metabolic syndrome and progression of nephropathy depend on sex. We examined a protective effect of estradiol against nephropathy in metabolic syndrome through the modulation of the arachidonic acid metabolism by activating the 5-lipoxygenase and cytochrome p450 4A pathways. 28 female Wistar rats were divided into four groups of seven animals each: control, intact metabolic syndrome, ovariectomized metabolic syndrome, and metabolic syndrome ovariectomized plus estradiol. Blood pressure, body weight, body fat, triglycerides, insulin, HOMA-index, albuminuria, and TNF-α were increased in ovariectomized metabolic syndrome rats (p < 0.001). The perfusion pressure in isolated kidneys of ovariectomized metabolic syndrome rats in presence of 4 μg of arachidonic acid was increased. The inhibitors of the arachidonic acid metabolism Baicalein, Miconazole, and Indomethacin in these rats decreased the perfusion pressure by 57.62%, 99.83%, and 108.5%, respectively and they decreased creatinine clearance and the arachidonic acid percentage. Phospholipase A2 expression in the kidney of ovariectomized metabolic syndrome rats was not modified. 5-lipoxygenase was increased in metabolic syndrome ovariectomized rats while cytochrome p450 4A was decreased. In conclusion, the loss of estradiol increases renal damage while the treatment with estradiol benefits renal function by modulating arachidonic acid metabolism through the 5-lipoxygenase and cytochrome p450 4A pathways.

Exposure to non-nutritive sweeteners during pregnancy and lactation: Impact in programming of metabolic diseases in the progeny later in life

The nutritional environment during embryonic, fetal and neonatal development plays a crucial role in the offspring's risk of developing diseases later in life. Although non-nutritive sweeteners (NNS) provide sweet taste without contributing to energy intake, animal studies showed that long-term consumption of NSS, particularly aspartame, starting during the perigestational period may predispose the offspring to develop obesity and metabolic syndrome later in life. In this paper, we review the impact of NNS exposure during the perigestational period on the long-term disease risk of the offspring, with a particular focus on metabolic diseases. Some mechanisms underlying NNS adverse metabolic effects have been proposed, such as an increase in intestinal glucose absorption, alterations in intestinal microbiota, induction of oxidative stress and a dysregulation of appetite and reward responses. The data reviewed herein suggest that NNS consumption by pregnant and lactating women should be looked with particular caution and requires further research.

Curcumin maintains cardiac and mitochondrial function in chronic kidney disease

Curcumin, a natural pigment with antioxidant activity obtained from turmeric and largely used in traditional medicine, is currently being studied in the chemoprevention of several diseases for its pleiotropic effects and nontoxicity. In chronic renal failure, the pathogenic mechanisms leading to cardiovascular disorders have been associated with increased oxidative stress, a process inevitably linked with mitochondrial dysfunction. Thus, in this study we aimed at investigating if curcumin pretreatment exerts cardioprotective effects in a rat model of subtotal nephrectomy (5/6Nx) and its impact on mitochondrial homeostasis. Curcumin was orally administered (120mg/kg) to Wistar rats 7 days before nephrectomy and after surgery for 60 days (5/6Nx+curc). Renal dysfunction was detected a few days after nephrectomy, whereas changes in cardiac function were observed until the end of the protocol. Our results indicate that curcumin treatment protects against pathological remodeling, diminishes ischemic events, and preserves cardiac function in uremic rats. Cardioprotection was related to diminished reactive oxygen species production, decreased oxidative stress markers, increased antioxidant response, and diminution of active metalloproteinase-2. We also observed that curcumin's cardioprotective effects were related to maintaining mitochondrial function. Aconitase activity was significantly higher in the 5/6Nx + curc (408.5±68.7nmol/min/mg protein) than in the 5/6Nx group (104.4±52.3nmol/min/mg protein, P<0.05), and mitochondria from curcumin-treated rats showed enhanced oxidative phosphorylation capacities with both NADH-linked substrates and succinate plus rotenone (3.6±1 vs 1.1±0.9 and 3.1±0.7 vs 1.2±0.8, respectively, P<0.05). The mechanisms involved in cardioprotection included both direct antioxidant effects and indirect strategies that could be related to protein kinase C-activated downstream signaling.

Effect of Diamel in patients with metabolic syndrome: a randomized double-blind placebo-controlled study

BACKGROUND

The aim of the present study was to determine whether the administration of Diamel, marketed as a food supplement by Catalysis Laboratories (Madrid, Spain) could improve any of the components of metabolic syndrome (MS), as well as insulin resistance and sensitivity.

METHODS

In all, 100 patients with MS (19-70 years of age) who satisfied the World Health Organization criteria for MS were included in the study. Participants were randomly assigned to receive either oral Diamel or a placebo (while maintaining a diet appropriate to their weight and physical activity) at a dose of two capsules before each of the three main meals each day for 1 year. Anthropometric indices, blood pressure, fasting plasma glucose, lipid profile, insulin, creatinine, and uric acid (UA) were determined. Insulin resistance (IR) was assessed and three indirect indices were used to calculate insulin sensitivity (IS).

RESULTS

Compared with placebo, Diamel improved fasting insulin concentrations, IS, and IR and reduced UA concentrations from 6 months until the end of treatment (P < 0.05 for all). In addition, after 12 months treatment with Diamel, significant changes from baseline were seen for mean fasting insulin (P < 0.05), UA (P < 0.05), IR (P < 0.001), and IS (P < 0.001), whereas no such changes were seen in the placebo-treated group. Improvements were noted in body mass index, IR, and IS in both groups.

CONCLUSIONS

Long-term Diamel treatment, combined with lifestyle changes, was beneficial for IR and IS, and reduced serum UA levels in patients with MS.

Short-term changes of the urine metabolome after bariatric surgery

Bariatric surgery leads to a loss of excess weight and to a remission of diabetes in a majority of patients. In an attempt to explain these underlying mechanisms, a broad range of metabolic alterations have been suggested. We aimed to investigate short-term changes in the urinary metabolome after bariatric surgery. Data for 50 patients who underwent bariatric surgery at the Municipal Hospital of Dresden-Neustadt, Germany, were used. Healthy controls were selected from the Study of Health in Pomerania. Non-fasting, spontaneous urine samples were collected, (1)H NMR spectroscopic analysis was performed, and metabolites were quantified (Chenomx NMR suite). Orthogonal projections to latent structures discriminant analysis (OPLS-DA) models were carried out (pre-operative versus controls, and post-operative versus controls). On the basis of the urine metabolome separations between pre-operative (predictive ability Q2Y=85.6%; total explained variance R2X=58.3%), or post-operative (Q2Y=82.1%; R2X=44.4%) and controls were possible. Metabolites including hippuric acid, 3-hydroxybutyrate, 2-hydroxyisobutyrate, and trigonelline, were altered among patients. In obese patients, 2-hydroxyisobutyrate levels were higher, whereas trigonelline and hippuric acid levels were lower than in controls. The highest levels of 3-hydroxybutyrate were found in post-operative samples, whereas the metabolite was not present in controls, and only at low levels in pre-operative samples. In conclusion, we demonstrated that the urinary metabotype differs between obese patients and healthy controls. The metabolic alterations identified after bariatric procedures increase our knowledge about the metabolic traits associated with weight reduction. Whether urinary metabotypes might be used for early prediction of a successful bariatric procedure should be evaluated in long-term observations.