| 1. |
- Holleboom, Adriaan G, et al.
(author)
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Heterozygosity for a Loss-of-Function Mutation in GALNT2 Improves Plasma Triglyceride Clearance in Man
- 2011
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In: Cell Metabolism. - : Elsevier. - 1550-4131 .- 1932-7420. ; 14:6, s. 811-8
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Journal article (peer-reviewed)abstract
- Genome-wide association studies have identified GALNT2 as a candidate gene in lipid metabolism, but it is not known how the encoded enzyme ppGalNAc-T2, which contributes to the initiation of mucin-type O-linked glycosylation, mediates this effect. In two probands with elevated plasma high-density lipoprotein cholesterol and reduced triglycerides, we identified a mutation in GALNT2. It is shown that carriers have improved postprandial triglyceride clearance, which is likely attributable to attenuated glycosylation of apolipoprotein (apo) C-III, as observed in their plasma. This protein inhibits lipoprotein lipase (LPL), which hydrolyses plasma triglycerides. We show that an apoC-III-based peptide is a substrate for ppGalNAc-T2 while its glycosylation by the mutant enzyme is impaired. In addition, neuraminidase treatment of apoC-III which removes the sialic acids from its glycan chain decreases its potential to inhibit LPL. Combined, these data suggest that ppGalNAc-T2 can affect lipid metabolism through apoC-III glycosylation, thereby establishing GALNT2 as a lipid-modifying gene.
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| 2. |
- Kootte, R. S., et al.
(author)
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Improvement of Insulin Sensitivity after Lean Donor Feces in Metabolic Syndrome Is Driven by Baseline Intestinal Microbiota Composition
- 2017
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In: Cell Metabolism. - : Elsevier BV. - 1550-4131. ; 26:4, s. 611-619
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Journal article (peer-reviewed)abstract
- The intestinal microbiota has been implicated in insulin resistance, although evidence regarding causality in humans is scarce. We therefore studied the effect of lean donor (allogenic) versus own (autologous) fecal microbiota transplantation (FMT) to male recipients with the metabolic syndrome. Whereas we did not observe metabolic changes at 18 weeks after FMT, insulin sensitivity at 6 weeks after allogenic FMT was significantly improved, accompanied by altered microbiota composition. We also observed changes in plasma metabolites such as gamma-aminobutyric acid and show that metabolic response upon allogenic FMT (defined as improved insulin sensitivity 6 weeks after FMT) is dependent on decreased fecal microbial diversity at baseline. In conclusion, the beneficial effects of lean donor FMT on glucose metabolism are associated with changes in intestinal microbiota and plasma metabolites and can be predicted based on baseline fecal microbiota composition.
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| 3. |
- Schnitzler, J. G., et al.
(author)
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Nile Red Quantifier: A novel and quantitative tool to study lipid accumulation in patient-derived circulating monocytes using confocal microscopy
- 2017
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In: Journal of Lipid Research. - 0022-2275. ; 58:11, s. 2210-2219
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Journal article (peer-reviewed)abstract
- The inflammatory profile of circulating monocytes is an important biomarker for atherosclerotic plaque vulnerability. Recent research revealed that peripheral lipid uptake by monocytes alters their phenotype toward an inflammatory state and this coincides with an increased lipid droplet (LD) content. Determination of lipid content of circulating monocytes is, however, not very well established. Based on Nile Red (NR) neutral LD imaging, using confocal microscopy and computational analysis, we developed NR Quantifier (NRQ), a novel quantification method to assess LD content in monocytes. Circulating monocytes were isolated from blood and used for the NR staining procedure. In monocytes stained with NR, we clearly distinguished, based on 3D imaging, phospholipids and exclusively intracellular neutral lipids. Next, we developed and validated NRQ, a semi-automated quantification program that detects alterations in lipid accumulation. NRQ was able to detect LD alterations after ex vivo exposure of isolated monocytes to freshly isolated LDL in a time-and dose-dependent fashion. Finally, we validated NRQ in patients with familial hypercholesterolemia and obese subjects in pre-and postprandial state. In conclusion, NRQ is a suitable tool to detect even small differences in neutral LD content in circulating monocytes using NR staining. Copyright © 2017 by the American Society for Biochemistry and Molecular Biology, Inc.
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| 4. |
- Smits, L. P., et al.
(author)
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Effect of Vegan Fecal Microbiota Transplantation on Carnitine- and Choline-Derived Trimethylamine-N-Oxide Production and Vascular Inflammation in Patients With Metabolic Syndrome
- 2018
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In: Journal of the American Heart Association. - : Ovid Technologies (Wolters Kluwer Health). - 2047-9980. ; 7:7
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Journal article (peer-reviewed)abstract
- BackgroundIntestinal microbiota have been found to be linked to cardiovascular disease via conversion of the dietary compounds choline and carnitine to the atherogenic metabolite TMAO (trimethylamine-N-oxide). Specifically, a vegan diet was associated with decreased plasma TMAO levels and nearly absent TMAO production on carnitine challenge. Methods and ResultsWe performed a double-blind randomized controlled pilot study in which 20 male metabolic syndrome patients were randomized to single lean vegan-donor or autologous fecal microbiota transplantation. At baseline and 2weeks thereafter, we determined the ability to produce TMAO from d(6)-choline and d(3)-carnitine (eg, labeled and unlabeled TMAO in plasma and 24-hour urine after oral ingestion of 250mg of both isotope-labeled precursor nutrients), and fecal samples were collected for analysis of microbiota composition. F-18-fluorodeoxyglucose positron emission tomography/computed tomography scans of the abdominal aorta, as well as exvivo peripheral blood mononuclear cell cytokine production assays, were performed. At baseline, fecal microbiota composition differed significantly between vegans and metabolic syndrome patients. With vegan-donor fecal microbiota transplantation, intestinal microbiota composition in metabolic syndrome patients, as monitored by global fecal microbial community structure, changed toward a vegan profile in some of the patients; however, no functional effects from vegan-donor fecal microbiota transplantation were seen on TMAO production, abdominal aortic F-18-fluorodeoxyglucose uptake, or exvivo cytokine production from peripheral blood mononuclear cells. ConclusionsSingle lean vegan-donor fecal microbiota transplantation in metabolic syndrome patients resulted in detectable changes in intestinal microbiota composition but failed to elicit changes in TMAO production capacity or parameters related to vascular inflammation.
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| 5. |
- Bakker, G. J., et al.
(author)
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Oral vancomycin treatment does not alter markers of postprandial inflammation in lean and obese subjects
- 2019
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In: Physiological Reports. - : Wiley. - 2051-817X. ; 7:16
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Journal article (peer-reviewed)abstract
- Intake of a high-fat meal induces a systemic inflammatory response in the postprandial which is augmented in obese subjects. However, the underlying mechanisms of this response have not been fully elucidated. We aimed to assess the effect of gut microbiota modulation on postprandial inflammatory response in lean and obese subjects. Ten lean and ten obese subjects with metabolic syndrome received oral vancomycin 500 mg four times per day for 7 days. Oral high-fat meal tests (50 g fat/m(2) body surface area) were performed before and after vancomycin intervention. Gut microbiota composition, leukocyte counts, plasma lipopolysaccharides (LPS), LPS-binding protein (LBP), IL-6 and MCP-1 concentrations and monocyte CCR2 and cytokine expression were determined before and after the high-fat meal. Oral vancomycin treatment resulted in profound changes in gut microbiota composition and significantly decreased bacterial diversity in both groups (phylogenetic diversity pre- versus post-intervention: lean, 56.9 +/- 7.8 vs. 21.4 +/- 6.6, P < 0.001; obese, 53.9 +/- 7.8 vs. 21.0 +/- 5.9, P < 0.001). After intervention, fasting plasma LPS significantly increased (lean, median [IQR] 0.81 [0.63-1.45] EU/mL vs. 2.23 [1.33-3.83] EU/mL, P = 0.017; obese, median [IQR] 0.76 [0.45-1.03] EU/mL vs. 1.44 [1.11-4.24], P = 0.014). However, postprandial increases in leukocytes and plasma LPS were unaffected by vancomycin in both groups. Moreover, we found no changes in plasma LBP, IL-6 and MCP-1 or in monocyte CCR2 expression. Despite major vancomycin-induced disruption of the gut microbiota and increased fasting plasma LPS, the postprandial inflammatory phenotype in lean and obese subjects was unaffected in this study.
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| 6. |
- Hassing, H. C., et al.
(author)
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SULF2 Strongly Prediposes to Fasting and Postprandial Triglycerides in Patients with Obesity and Type 2 Diabetes Mellitus
- 2014
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In: Obesity. - : Wiley. - 1930-7381 .- 1930-739X. ; 22:5, s. 1309-1316
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Journal article (peer-reviewed)abstract
- Objective: Hepatic overexpression of sulfatase-2 (SULF2), a heparan sulfate remodeling enzyme, strongly contributes to high triglyceride (TG) levels in obese, type 2 diabetic (T2DM) db/db mice. Nevertheless, data in humans are lacking. Here, the association of human hepatic SULF2 expression and SULF2 gene variants with TG metabolism in patients with obesity and/or T2DM was investigated. Methods: Liver biopsies from 121 obese subjects were analyzed for relations between hepatic SULF2 mRNA levels and plasma TG. Associations between seven SULF2 tagSNPs and TG levels were assessed in 210 obese T2DM subjects with dyslipidemia. Replication of positive findings was performed in 1,316 independent obese T2DM patients. Postprandial TRL clearance was evaluated in 29 obese T2DM subjects stratified by SULF2 genotype. Results: Liver SULF2 expression was significantly associated with fasting plasma TG (r = 0.271; P = 0.003) in obese subjects. The SULF2 rs2281279(A>G) SNP was reproducibly associated with lower fasting plasma TG levels in obese T2DM subjects (P < 0.05). Carriership of the minor G allele was associated with lower levels of postprandial plasma TG (P < 0.05) and retinyl esters levels (P < 0.001). Conclusions: These findings implicate SULF2 as potential therapeutic target in the atherogenic dyslipidemia of obesity and T2DM.
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| 7. |
- Udayappan, S. D., et al.
(author)
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Intestinal Ralstonia pickettii augments glucose intolerance in obesity
- 2017
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In: Plos One. - : Public Library of Science (PLoS). - 1932-6203. ; 12:11
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Journal article (peer-reviewed)abstract
- An altered intestinal microbiota composition has been implicated in the pathogenesis of metabolic disease including obesity and type 2 diabetes mellitus (T2DM). Low grade inflammation, potentially initiated by the intestinal microbiota, has been suggested to be a driving force in the development of insulin resistance in obesity. Here, we report that bacterial DNA is present in mesenteric adipose tissue of obese but otherwise healthy human subjects. Pyrosequencing of bacterial 16S rRNA genes revealed that DNA from the Gram-negative species Ralstonia was most prevalent. Interestingly, fecal abundance of Ralstonia pickettii was increased in obese subjects with pre-diabetes and T2DM. To assess if R. pickettii was causally involved in development of obesity and T2DM, we performed a proof-of-concept study in diet-induced obese (DIO) mice. Compared to vehicle-treated control mice, R. pickettii-treated DIO mice had reduced glucose tolerance. In addition, circulating levels of endotoxin were increased in R. pickettii-treated mice. In conclusion, this study suggests that intestinal Ralstonia is increased in obese human subjects with T2DM and reciprocally worsens glucose tolerance in DIO mice.
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| 8. |
- Bouter, K. E. C., et al.
(author)
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Differential metabolic effects of oral butyrate treatment in lean versus metabolic syndrome subjects article
- 2018
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In: Clinical and Translational Gastroenterology. - : Ovid Technologies (Wolters Kluwer Health). - 2155-384X. ; 9:5
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Journal article (peer-reviewed)abstract
- Background: Gut microbiota-derived short-chain fatty acids (SCFAs) have been associated with beneficial metabolic effects. However, the direct effect of oral butyrate on metabolic parameters in humans has never been studied. In this first in men pilot study, we thus treated both lean and metabolic syndrome male subjects with oral sodium butyrate and investigated the effect on metabolism. Methods: Healthy lean males (n = 9) and metabolic syndrome males (n = 10) were treated with oral 4 g of sodium butyrate daily for 4 weeks. Before and after treatment, insulin sensitivity was determined by a two-step hyperinsulinemic euglycemic clamp using [6,6-2H2]-glucose. Brown adipose tissue (BAT) uptake of glucose was visualized using 18F-FDG PET-CT. Fecal SCFA and bile acid concentrations as well as microbiota composition were determined before and after treatment. Results: Oral butyrate had no effect on plasma and fecal butyrate levels after treatment, but did alter other SCFAs in both plasma and feces. Moreover, only in healthy lean subjects a significant improvement was observed in both peripheral (median Rd: from 71 to 82 μmol/kg min, p < 0.05) and hepatic insulin sensitivity (EGP suppression from 75 to 82% p < 0.05). Although BAT activity was significantly higher at baseline in lean (SUVmax: 12.4 ± 1.8) compared with metabolic syndrome subjects (SUVmax: 0.3 ± 0.8, p < 0.01), no significant effect following butyrate treatment on BAT was observed in either group (SUVmax lean to 13.3 ± 2.4 versus metabolic syndrome subjects to 1.2 ± 4.1). Conclusions: Oral butyrate treatment beneficially affects glucose metabolism in lean but not metabolic syndrome subjects, presumably due to an altered SCFA handling in insulin-resistant subjects. Although preliminary, these first in men findings argue against oral butyrate supplementation as treatment for glucose regulation in human subjects with type 2 diabetes mellitus. © 2018 The Author(s).
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| 9. |
- De Groot, P., et al.
(author)
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Donor metabolic characteristics drive effects of faecal microbiota transplantation on recipient insulin sensitivity, energy expenditure and intestinal transit time
- 2020
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In: Gut. - : BMJ. - 0017-5749 .- 1468-3288. ; 69, s. 502-512
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Journal article (peer-reviewed)abstract
- Objective: Bariatric surgery improves glucose metabolism. Recent data suggest that faecal microbiota transplantation (FMT) using faeces from postbariatric surgery diet-induced obese mice in germ-free mice improves glucose metabolism and intestinal homeostasis. We here investigated whether allogenic FMT using faeces from post-Roux-en-Y gastric bypass donors (RYGB-D) compared with using faeces from metabolic syndrome donors (METS-D) has short-term effects on glucose metabolism, intestinal transit time and adipose tissue inflammation in treatment-naïve, obese, insulin-resistant male subjects. Design: Subjects with metabolic syndrome (n=22) received allogenic FMT either from RYGB-D or METS-D. Hepatic and peripheral insulin sensitivity as well as lipolysis were measured at baseline and 2 weeks after FMT by hyperinsulinaemic euglycaemic stable isotope (2H2-glucose and 2H5-glycerol) clamp. Secondary outcome parameters were changes in resting energy expenditure, intestinal transit time, faecal short-chain fatty acids (SCFA) and bile acids, and inflammatory markers in subcutaneous adipose tissue related to intestinal microbiota composition. Faecal SCFA, bile acids, glycaemic control and inflammatory parameters were also evaluated at 8 weeks. Results: We observed a significant decrease in insulin sensitivity 2 weeks after allogenic METS-D FMT (median rate of glucose disappearance: from 40.6 to 34.0 μmol/kg/min; p<0.01). Moreover, a trend (p=0.052) towards faster intestinal transit time following RYGB-D FMT was seen. Finally, we observed changes in faecal bile acids (increased lithocholic, deoxycholic and (iso)lithocholic acid after METS-D FMT), inflammatory markers (decreased adipose tissue chemokine ligand 2 (CCL2) gene expression and plasma CCL2 after RYGB-D FMT) and changes in several intestinal microbiota taxa. Conclusion: Allogenic FMT using METS-D decreases insulin sensitivity in metabolic syndrome recipients when compared with using post-RYGB-D. Further research is needed to delineate the role of donor characteristics in FMT efficacy in human insulin-resistant subjects. Trial registration number: NTR4327.
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| 10. |
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