27 research outputs found

    Mycoplasma Contamination Revisited: Mesenchymal Stromal Cells Harboring Mycoplasma hyorhinis Potently Inhibit Lymphocyte Proliferation In Vitro

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    Mesenchymal stromal cells (MSC) have important immunomodulatory effects that can be exploited in the clinical setting, e.g. in patients suffering from graft-versus-host disease after allogeneic stem cell transplantation. In an experimental animal model, cultures of rat T lymphocytes were stimulated in vitro either with the mitogen Concanavalin A or with irradiated allogeneic cells in mixed lymphocyte reactions, the latter to simulate allo-immunogenic activation of transplanted T cells in vivo. This study investigated the inhibitory effects of rat bone marrow-derived MSC subsequently found to be infected with a common mycoplasma species (Mycoplasma hyorhinis) on T cell activation in vitro and experimental graft-versus-host disease in vivo.We found that M. hyorhinis infection increased the anti-proliferative effect of MSC dramatically, as measured by both radiometric and fluorimetric methods. Inhibition could not be explained solely by the well-known ability of mycoplasmas to degrade tritiated thymidine, but likely was the result of rapid dissemination of M. hyorhinis in the lymphocyte culture.This study demonstrates the potent inhibitory effect exerted by M. hyorhinis in standard lymphocyte proliferation assays in vitro. MSC are efficient vectors of mycoplasma infection, emphasizing the importance of monitoring cell cultures for contamination

    Major Increase in Microbiota-Dependent Proatherogenic Metabolite TMAO One Year After Bariatric Surgery

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    Background: Trimethylamine-N-oxide (TMAO) is formed in the liver from trimethylamine (TMA), a product exclusively generated by the gut microbiota from dietary phosphatidylcholine and carnitine. An alternative pathway of TMAO formation from carnitine is via the microbiota-dependent intermediate γ-butyrobetaine (γBB). Elevated TMAO levels are associated with cardiovascular disease (CVD), but little is known about TMAO in obesity. Given the proposed contribution of microbiota alterations in obesity and type 2 diabetes (T2D), we investigated the potential impact of obesity, lifestyle-induced weight loss, and bariatric surgery on plasma levels of TMAO, its microbiota-dependent intermediate γBB, and its diet-dependent precursors carnitine and choline. Methods: TMAO, γBB, carnitine, and choline were measured by high-performance liquid chromatography in 34 obese individuals (17 with and 17 without T2D) undergoing bariatric surgery and 17 controls. Results: TMAO was not elevated in obese patients or reduced by lifestyle interventions but increased approximately twofold after bariatric surgery. Similar to TMAO, plasma levels of γBB were not influenced by lifestyle interventions but increased moderately after bariatric surgery. In contrast, carnitine and choline, which are abundant in nutrients, such as in red meat and eggs, and not microbiota dependent, were reduced after lifestyle interventions and rebounded after bariatric surgery. Conclusions: The major increase in TMAO after bariatric surgery was unexpected because high TMAO levels have been linked to CVD, whereas bariatric surgery is known to reduce CVD risk. Prospective studies of gut microbiota composition and related metabolites in relation to long-term cardiovascular risk after bariatric surgery are warranted

    Bariatric surgery improves lipoprotein profile in morbidly obese patients by reducing LDL cholesterol, apoB, and SAA/PON1 ratio, increasing HDL cholesterol, but has no effect on cholesterol efflux capacity

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    BACKGROUND: Bariatric surgery has been shown to reduce cardiovascular events and cause specific mortality for coronary artery disease in obese patients. Lipoprotein biomarkers relating to low-density lipoprotein (LDL), high-density lipoprotein (HDL), their subfractions, and macrophage cholesterol efflux have all been hypothesized to be of value in cardiovascular risk assessment. OBJECTIVES: The objective of this study was to examine the effect of a lifestyle intervention followed by bariatric surgery on the lipid profile of morbidly obese patients. METHODS: Thirty-four morbidly obese patients were evaluated before and after lifestyle changes and then 1 year after bariatric surgery. They were compared with 17 lean subjects. Several lipoprotein metrics, serum amyloid A (SAA), serum paraoxonase-1 (PON1), and macrophage cholesterol efflux capacity (CEC) were assessed. RESULTS: Average weight loss after the lifestyle intervention was 10.5% and 1 year after bariatric surgery was 33.9%. The lifestyle intervention significantly decreased triglycerides (TGs; 28.7 mg/dL, P amp;lt; .05), LDL cholesterol (LDL-C; 32.3 mg/dL, P amp;lt; .0001), and apolipoprotein B (apoB; 62.9 mu g/mL, P amp;lt; .001). Bariatric surgery further reduced TGs (-36.7 mg/dL, P amp;lt; .05), increased HDL cholesterol (+12 mg/dL, P amp;lt; .0001), and reductions in LDL-C and apoB were sustained. Bariatric surgery reduced large, buoyant LDL (P amp;lt; .0001), but had no effect on the small, dense LDL.The large HDL subfractions increased (P amp;lt; .0001), but there was no effect on the smaller HDL sub fractions. The ratio for SAA/PON1 was reduced after the lifestyle intervention (P amp;lt; .01) and further reduced after bariatric surgery (P amp;lt; .0001). Neither the lifestyle intervention nor bariatric surgery had any effect on CEC. CONCLUSIONS: Lifestyle intervention followed by bariatric surgery in 34 morbidly obese patients showed favorable effects on TGs, LDL-C, and apoB. HDL cholesterol and apoA1 was increased, apoB/apoA1 ratio as well as SAA/PON1 ratio reduced, but bariatric surgery did not influence CEC. (C) 2017 National Lipid Association. All rights reserved

    Plasma Lipopolysaccharide Is Closely Associated With Glycemic Control and Abdominal Obesity: Evidence from bariatric surgery

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    OBJECTIVE: It is of vital importance to elucidate the triggering factors of obesity and type 2 diabetes to improve patient care. Bariatric surgery has been shown to prevent and even cure diabetes, but the mechanism is unknown. Elevated levels of lipopolysaccharide (LPS) predict incident diabetes, but the sources of LPS are not clarified. The objective of the current study was to evaluate the potential impact of plasma LPS on abdominal obesity and glycemic control in subjects undergoing bariatric surgery. RESEARCH DESIGN AND METHODS: This was a prospective observational study involving a consecutive sample of 49 obese subjects undergoing bariatric surgery and 17 controls. Main assessments were plasma LPS, HbA(1c), adipose tissue volumes (computed tomography), and quantified bacterial DNA in adipose tissue compartments. RESULTS: Plasma levels of LPS were elevated in obese individuals compared with controls (P < 0.001) and were reduced after bariatric surgery (P = 0.010). LPS levels were closely correlated with HbA(1c) (r = 0.56; P = 0.001) and intra-abdominal fat volumes (r = 0.61; P < 0.001), but only moderately correlated with subcutaneous fat volumes (r = 0.33; P = 0.038). Moreover, there was a decreasing gradient (twofold) in bacterial DNA levels going from mesenteric via omental to subcutaneous adipose tissue compartments (P = 0.041). Finally, reduced LPS levels after bariatric surgery were directly correlated with a reduction in HbA(1c) (r = 0.85; P < 0.001). CONCLUSIONS: Our findings support a hypothesis of translocated gut bacteria as a potential trigger of obesity and diabetes, and suggest that the antidiabetic effects of bariatric surgery might be mechanistically linked to, and even the result of, a reduction in plasma levels of LPS
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