Differential effects of RYGB surgery and best medical treatment for obesity-diabetes on intestinal and islet adaptations in obese-diabetic ZDSD rats

Modification of gut-islet secretions after Roux-En-Y gastric bypass (RYBG) surgery contributes to its metabolic and anti-diabetic benefits. However, there is limited knowledge on tissue-specific hormone distribution post-RYGB surgery and how this compares with best medical treatment (BMT). In the present study, pancreatic and ileal tissues were excised from male Zucker-Diabetic Sprague Dawley (ZDSD) rats 8-weeks after RYGB, BMT (daily oral dosing with metformin 300mg/kg, fenofibrate 100mg/kg, ramipril 1mg/kg, rosuvastatin 10mg/kg and subcutaneous liraglutide 0.2mg/kg) or sham operation (laparotomy). Insulin, glucagon, somatostatin, PYY, GLP-1 and GIP expression patterns were assessed using immunocytochemistry and analyzed using ImageJ. After RYGB and BMT, body weight and plasma glucose were decreased. Intestinal morphometry was unaltered by RYGB, but crypt depth was decreased by BMT. Intestinal PYY cells were increased by both interventions. GLP-1- and GIP-cell counts were unchanged by RYGB but BMT increased ileal GLP-1-cells and decreased those expressing GIP. The intestinal contents of PYY and GLP-1 were significantly enhanced by RYGB, whereas BMT decreased ileal GLP-1. No changes of islet and beta-cell area or proliferation were observed, but the extent of beta-cell apoptosis and islet integrity calculated using circularity index were improved by both treatments. Significantly decreased islet alpha-cell areas were observed in both groups, while beta- and PYY-cell areas were unchanged. RYGB also induced a decrease in islet delta-cell area. PYY and GLP-1 colocalization with glucagon in islets was significantly decreased in both groups, while co-staining of PYY with glucagon was decreased and that with somatostatin increased. These data characterize significant cellular islet and intestinal adaptations following RYGB and BMT associated with amelioration of obesity-diabetes in ZDSD rats. The differential responses observed and particularly those within islets, may provide important clues to the unique ability of RYGB to cause diabetes remission

The European Modern Pollen Database (EMPD) project

Modern pollen samples provide an invaluable research tool for helping to interpret the quaternary fossil pollen record, allowing investigation of the relationship between pollen as the proxy and the environmental parameters such as vegetation, land-use, and climate that the pollen proxy represents. The European Modern Pollen Database (EMPD) is a new initiative within the European Pollen Database (EPD) to establish a publicly accessible repository of modern (surface sample) pollen data. This new database will complement the EPD, which at present holds only fossil sedimentary pollen data. The EMPD is freely available online to the scientific community and currently has information on almost 5,000 pollen samples from throughout the Euro-Siberian and Mediterranean regions, contributed by over 40 individuals and research groups. Here we describe how the EMPD was constructed, the various tables and their fields, problems and errors, quality controls, and continuing efforts to improve the available dat

RYGB surgery has modest effects on intestinal morphology and gut hormone populations in the bypassed biliopancreatic limb but causes reciprocal changes in GLP-2 and PYY in the alimentary limb.

Roux-en-Y gastric-bypass (RYGB) induced alterations in intestinal morphology and gut-cell hormone expression profile in the bypassed biliopancreatic-limb (BPL) versus the alimentary-limbs (AL) are poorly characterised. This pilot study has therefore explored effects following RYGB in high-fat-diet (HFD) and normal-diet (ND) rats. Female Wistar rats (4-week-old) were fed HFD or ND for 23-weeks prior to RYGB or sham surgeries. Immunohistochemical analysis of excised tissue was conducted three-weeks post-surgery. After RYGB, intestinal morphology of the BPL in both HFD and ND groups was unchanged with exception of a small decrease in villi width in the ND-RYGB and crypt depth in the HFD-RYGB group. However, in the AL, villi width was decreased in ND-RYGB rats but increased in the HFD-RYGB group. In addition, crypt depth decreased after RYGB in the AL of HFD rats. GIP positive cells in either limb of both groups of rats were unchanged by RYGB. Similarly, there was little change in GLP-1 positive cells, apart from a small decrease of numbers in the villi of the BPL in HFD rats. RYGB increased GLP-2 cell numbers in the AL of ND-RYGB rats, including in both crypts and villi. This was associated with decreased numbers of cells expressing PYY in the AL of ND-RYGB rats. The BPL appears to maintain normal morphology and unchanged enteroendocrine cell populations despite being bypassed in RYGB-surgery. In contrast, in the AL, villi area is generally enhanced post-RYGB in ND rats with increased numbers of GLP-2 positive cells and decreased expression of PYY

Effects of RYGB, BMT and sham surgery on gut hormone co-localization in islets 8 weeks post-experimental intervention.

(A) Representative islet images showing PYY (red) with glucagon & somatostatin (green), GLP-1 (red) with glucagon (green). Nuclei are demonstrated using DAPI staining (blue). Quantification of co-localization of PYY with (B) glucagon and (C) somatostatin, and (D) GLP-1 with glucagon are also shown. Arrows indicate cells that are positive for both PYY and glucagon or somatostatin, and GLP-1 with glucagon. Normal SD rats are included for comparison. Values are mean ± SEM (n = 4) with statistical significance evaluated using one-way ANOVA. *p<0.05, **p<0.01, ***p<0.001 compared to sham rats. Analyses carried out on 60–80 islets per group.</p

Summary of results and their possible biological significance after RYGB surgery.

Summary of results and their possible biological significance after RYGB surgery.</p

Effects of RYGB, BMT and sham surgery on PYY positive cell distribution in the ileum of ZDSD rat intestine.

(A) Representative images showing PYY (green); arrows indicate PYY positive cells. Nuclei are demonstrated using DAPI staining (blue). (B) number of PYY positive cells per mm2 of ileum, (C) number of PYY positive cells per mm2 of crypt and (D) number of PYY positive cells per mm2 of villi analyzed in ileum sections. Normal SD rats are included for comparison. Values are mean ± SEM (n = 4) with statistical significance evaluated using one-way ANOVA. *p<0.05, ***p<0.001 compared to sham. Analyses carried out on ~200 cells per group.</p

Effects of RYGB, BMT and sham surgery on GLP-1 positive cell distribution in the ileum of ZDSD rat intestine.

(A) Representative images showing GLP-1 (green); arrows indicate GLP-1 positive cells. Nuclei are demonstrated using DAPI staining (blue). (B) number of GLP-1 positive cells per mm2 of ileum, (C) number of GLP-1 positive cells per mm2 of crypt and (D) number of GLP-1 positive cells per mm2 of villi analyzed in ileum sections. Normal SD rats are included for comparison. Values are mean ± SEM (n = 4) with statistical significance evaluated using one-way ANOVA. **p<0.01 compared to sham rats. Analyses carried out on ~200 cells per group.</p

Effects of RYGB, BMT and sham surgery on ileal hormone content in ZDSD rats.

(A) Ileal PYY content (pg/mg protein), (B) ileal GLP-1 content (nmol/mg protein) and (C) ileal GIP content (pg/mg protein). Normal SD rats are included for comparison. Values are mean ± SEM (n = 4) with statistical significance evaluated using one-way ANOVA. *p<0.05, ***p<0.001 compared to sham.</p