Access to tetra-N-acetyl-chitopentaose by chemical N-acetylation of glucosamine pentamer

International audienceNowadays, the easy access of tetra-N-acetyl-chitopentaose and its counterparts is highly interesting since such chemical compounds are precursors of biological signal molecules with a strong agro-economic impact. The chemical synthesis of tetra-N-acetyl-chitopentaose by controlled N-acetylation of the glucosamine pentamer hydrochloride under mild conditions is described herein. A systematic study on the influence of the different parameters involved in this reaction, such as the solvent, the acetylating agent, and the base used for the deprotonation of ammonium groups of the starting material was carried out. The characterization of final reaction products by HPLC and MALDI-TOF mass spectrometry showed that each of these parameters affects differently the acetylation reaction. Whereas the solvent plays an important role in the N- or O-acetylation selectivity, the acetylating agent and the base were found to influence both the degree of N-acetylation and the distribution of the partially N-acetylated derivatives in the product mixtures. Based on these results, optimized reaction conditions have been established allowing tetra-N-acetyl-chitopentaose to be synthesized in a one-pot deprotonation/N-acetylation of the glucosamine pentamer hydrochloride in a moderate yield (ca 30%)

Malabsorption and Intestinal Adaptation After One Anastomosis Gastric Bypass compared to Roux-en-Y Gastric Bypass in Rats : Protein malabsorption after Mini Gastric Bypass

International audienceThe technically easier one-anastomosis (mini) gastric bypass (MGB) is associated with similar metabolic improvements and weight loss as the Roux-en-Y gastric bypass (RYGB). However, MGB is controversial and suspected to result in greater malabsorption than RYGB.In this study, we compared macronutrient absorption and intestinal adaptation after MGB or RYGB in rats. Body weight and food intake were monitored and glucose tolerance tests were performed in rats subjected to MGB, RYGB, or sham surgery. Carbohydrate, protein, and lipid absorption was determined by fecal analyses. Intestinal remodeling was evaluated by histology and immunohistochemistry. Peptide and amino acid transporter mRNA levels were measured in the remodeled intestinal mucosa and those of anorexigenic and orexigenic peptides in the hypothalamus. The MGB and RYGB surgeries both resulted in a reduction of body weight and an improvement of glucose tolerance relative to sham rats. Hypothalamic orexigenic neuropeptide gene expression was higher in MGB rats than in RYGB or sham rats. Fecal losses of calories and proteins were greater after MGB than RYGB or sham surgery. Intestinal hyperplasia occurred after MGB and RYGB with increased jejunum diameter, higher villi, and deeper crypts than in sham rats. Peptidase and peptide or amino acid transporter genes were overexpressed in jejunal mucosa from MGB rats but not RYGB rats. In rats, MGB led to greater protein malabsorption and energy loss than RYGB. This malabsorption was not compensated by intestinal overgrowth and increased expression of peptide transporters in the jejunum

Comparison of Repeat Sleeve Gastrectomy and Roux-en-Y Gastric Bypass in Case of Weight Loss Failure After Sleeve Gastrectomy

International audienceBackground Few series are available on the results of repeat sleeve gastrectomy (re-SG) and Roux-en-Y gastric bypass (RYGB) performed to manage the failure of primary sleeve gastrectomy (SG). The objective of this study was to compare the short- and medium-term outcomes of re-SG and RYGB after SG. Material & Methods Between January 2010 and December 2017, patients undergoing re-SG (n = 61) and RYGB (n = 83) for failure of primary SG were included in this study. Revisional surgery was proposed for patients with insufficient excess weight loss (EWL <= 50%) or weight regain. The primary endpoint was the comparison of weight loss in the re-SG group and the RYGB group at the 1-year follow-up. The secondary endpoints were overall mortality and morbidity, specific morbidity, length of stay, weight loss, and correction of comorbidities. Results The mean interval between SG and re-SG was 41.5 vs. 43.2 months between SG and RYGB (p = 0.32). The mean operative time was 103 min (re-SG group) vs. 129.4 min (RYGB group). One death (1.7%; re-SG group) and 25 complications (17.4%; 9 in the re-SG group, 16 in the RYGB group) were observed. At the 1 year, mean body mass index was 31.6 in the re-SG group and 32.5 in the RYGB group (p = 0.61) and excess weight loss was 69.5 vs. 61.2, respectively (p = 0.05). Conclusion Re-SG and RYGB as revisional surgery for SG are feasible with acceptable outcomes and similar results on weight loss on the first postoperative year