Roux-en-Y gastric bypass (RYGB) has become a prominent therapeutic option for long-term treatment of morbid obesity and type 2 diabetes mellitus (T2D). Cross talk and pathogenetic consequences of RYGB-induced profound effects on metabolism and gut microbiome are poorly understood. The aim of the present study therefore was to characterize intra-individual changes of gut microbial composition before and 3 months after RYGB by metagenomic sequencing in morbidly obese patients (body mass index (BMI)440 kg m À 2 ) with T2D. Subsequently, metagenomic data were correlated with clinical indices. Based on gene relative abundance profile, 1061 species, 729 genera, 44 phyla and 5127 KO (KEGG Orthology) were identified. Despite high diversity, bacteria could mostly be assigned to seven bacterial divisions. The overall metagenomic RYGB-induced shift was characterized by a reduction of Firmicutes and Bacteroidetes and an increase of Proteobacteria. Twenty-two microbial species and 11 genera were significantly altered by RYGB. Using principal component analysis, highly correlated species were assembled into two common components. Component 1 consisted of species that were mainly associated with BMI and C-reactive protein. This component was characterized by increased numbers of Proteobacterium Enterobacter cancerogenus and decreased Firmicutes Faecalibacterium prausnitzii and Coprococcus comes. Functional analysis of carbohydrate metabolism by KO revealed significant effects in 13 KOs assigned to phosphotransferase system. Spearmen's Rank correlation indicated an association of 10 species with plasma total-or low-density lipoprotein cholesterol, and 5 species with triglycerides. F. prausnitzii was directly correlated to fasting blood glucose. This is the first clinical demonstration of a profound and specific intra-individual modification of gut microbial composition by full metagenomic sequencing. A clear correlation exists of microbiome composition and gene function with an improvement in metabolic and inflammatory parameters. This will allow to develop new diagnostic and therapeutic strategies based on metagenomic sequencing of the human gut microbiome.
Islet transplantation as a biological β-cell replacement therapy has emerged as a promising option for achieving restoration of metabolic control in type 1 diabetes patients. However, partial or complete loss of islet graft function occurs in relatively short time (months to few years) after implantation. The high rate of early transplant dysfunction has been attributed to poorly viable and/or functional islets and is mediated by innate inflammatory response at the intravascular (hepatic) transplant site and critical lack of initial nutrient/oxygen supply prior to islet engraftment. In addition, the diabetogenic effect of mandatory immunosuppressive agents, limited control of alloimmunity, and the recurrence of autoimmunity limit the long-term success of islet transplantation. In order to abrogate instant blood-mediated inflammatory reaction and to provide oxygen supply for the islet graft, we have developed an extravascular (subcutaneous) transplant macrochamber (the 'βAir' device). This device contains islets immobilized in alginate, protected from the immune system by a thin hydrophilized teflon membrane impregnated with alginate and supplied with oxygen by daily refueling with oxygen-CO (2) mixture. We have demonstrated successful utilization of the oxygen-refueling macrochamber for sustained islet viability and function as well as immunoprotection after allogeneic subcutaneous transplantation in healthy minipigs. Considering the current limitations of intraportal islet engraftment and the restricted indication for islet transplantation mainly due to necessary immunosuppressive therapy, this work could very likely lead to remarkable improvements in the procedure and moreover opens up further strategies for porcine islet cell xenotransplantation.
OBJECTIVE -Adiponectin encoded by the ADIPOQ gene modulates insulin sensitivity and glucose homeostasis. The aim of the current study was to investigate whether ADIPOQ gene variants in the promoter region predict adiponectin levels and type 2 diabetes progression. RESEARCH DESIGN AND METHODS-A total of 550 subjects with increased risk of type 2 diabetes were investigated; they underwent a 75-g oral glucose tolerance test, repeated after 3 years. Adiponectin levels were analyzed, and two ADIPOQ promoter variant single nucleotide polymorphisms, Ϫ11391GϾA and Ϫ11377CϾG, were genotyped.RESULTS -Tertiles of the adjusted adiponectin levels were associated with single nucleotide polymorphism Ϫ11391GϾA and Ϫ11377CϾG haplotypes (P Ͻ 0.0001). Carriers of the intermediate/high-level haplotype combination showed a bisected diabetes risk at the 3-year follow-up and were characterized by a "regression" of glucose tolerance. Evolution of disease status correlates with preexisting low adiponectin levels at inclusion rather than with variation in adiponectin levels.CONCLUSIONS -We present data that gene variants in the ADIPOQ promoter region are associated with variations in adiponectin levels and thus with future type 2 diabetes and disease progression. Diabetes Care 29:1645-1650, 2006I n conjunction with environmental and behavioral factors, genetic susceptibility is an integral part in the pathogenesis of type 2 diabetes (1). There is evidence that adipose tissue not only functions as an energy reservoir but also produces and secretes several cytokines that modulate energy metabolism and glucose homeostasis (2-5).The ADIPOQ gene encoding adiponectin has been mapped to chromosome 3q27 (6) and is expressed in adult adipocyte tissue (7). Both reduced expression of adiponectin and lower serum adiponectin levels were detected in patients with obesity, type 2 diabetes, and coronary artery disease (8,9). Moreover, treatment of diabetic mice with adiponectin was shown to induce a marked improvement in insulin sensitivity (10).Clinical studies showed that an altered serum adiponectin level is an independent risk factor for progression to type 2 diabetes (11,12). Screening for mutation within the adiponectin gene in the French, AfricanAmerican, and Swedish populations (13-15) revealed an association of haplotypes Ϫ11391GϾA and Ϫ11377CϾG single nucleotide polymorphisms (SNPs) comprising promoter and coding variants of the adiponectin gene with insulin resistance and type 2 diabetes (13,14,16 -18) as well as adiponectin levels (16,19). These data provide evidence that genetic variation within the ADIPOQ gene may be part of the genetic determinants of risk of type 2 diabetes and insulin resistance (13,18) via modulation of adiponectin levels (16,17,20).By using a prospective cohort study, our objective in this investigation was to test the hypothesis that adiponectin promoter variants predict adiponectin levels and that adiponectin promoter variants and/or adiponectin serum levels predict type 2 diabetes progression. Because of the prev...
CRH, the principal regulator of the hypothalamic-pituitary-adrenal axis and modulator of autonomic nervous system activity, also participates in the regulation of appetite and energy expenditure. Antalarmin, a pyrrolopyrimidine compound, antagonizes CRH type 1 receptor-mediated effects of CRH, including pituitary ACTH release, stress behaviors, and acute inflammation. We administered antalarmin chronically to evaluate its effects on hypothalamic-pituitary-adrenal axis function and metabolic status. Adult male rats were treated twice daily with 20 mg/kg of i.p. antalarmin or placebo over 11 days. The animals were weighed; plasma ACTH, corticosterone, leptin, and blood glucose levels were determined; and morphometric analyses were performed to determine adrenal size and structure, including sizing, histochemistry, immunohistochemistry, and electron microscopy. Leptin messenger RNA expression in peripheral fat was analyzed by Northern blot. Antalarmin decreased plasma ACTH (mean +/- SD, 2.62 +/- 0.063 pg/ml) and corticosterone concentrations (10.21 +/- 1.80 microg/dl) compared with those in vehicle-treated rats [respectively, 5.3 +/- 2.0 (P < 0.05) and 57.02 +/- 8.86 (P < 0.01)]. Antalarmin had no significant effect on body weight, plasma leptin, or blood glucose concentrations or fat cell leptin messenger RNA levels. The width of the adrenal cortex of animals treated with antalarmin was reduced by 31% compared with that in controls without atrophy of the gland. On the ultrastructural level, adrenocortical cells were in a hypofunctional state characterized by reduced vascularization, increased content of lipid droplets, and tubulovesicular mitochondria with fewer inner membranes. The apoptotic rate was increased in the outer zona fasciculata of animals treated with the antagonist (26.6 +/- 3.58%) compared with that in placebo-treated controls (6.8 +/- 0.91%). We conclude that chronic administration of antalarmin does not affect body weight, carbohydrate metabolism, or leptin expression, whereas it reduces adrenocortical function mildly, without anatomical, clinical, or biochemical evidence of causing adrenal atrophy. These results are promising for future uses of such an antagonist in the clinic.
A new role for the adrenal medulla as a regulator of adrenocortical function has been postulated. However, there has been no idea as to how such a cellular interaction within the human adrenal gland could take place. In this study we were able to demonstrate with the help of specific immunostaining of cortical and chromaffin cells, respectively, that the two endocrine systems are interwoven with each other to an astonishing degree. Protrusions, clusters, islets, and single cortical cells were made visible by immunostaining with an antibody against 17 alpha-hydroxylase cytochrome P450 enzyme. They occurred diffusely within the entire adrenal medulla, providing ample contact zones for paracrine interactions. Specific immunostaining for the neuroendocrine protein chromogranin-A identified the occurrence of chromaffin cells within all three zones of the human adrenal cortex, including the zona glomerulosa. In an ultrastructural analysis, cortical and chromaffin cells were found in all zones in direct apposition, providing the possibility for direct intercellular exchange. The close morphological colocalization of cortical and chromaffin cells revealed in this study may constitute the basis for the growing evidence of relevant intraadrenal paracrine mechanisms within the human adrenal gland.
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