Diabetes recurrence after metabolic surgeries correlates with re-impaired insulin sensitivity rather than beta-cell function

Figure 1 Areas under the curves for oral glucose tolerance test; of rats at baseline, 4 and 12 wk after operations. ^aP < 0.05 vs Sham group at 4 wk postoperatively, ^cP < 0.05 vs Sham group at 12 wk postoperatively, ^eP < 0.05 vs SG-HFD group at 4 wk postoperatively, ^gP < 0.05 vs DJB-HFD group at 4 wk postoperatively. AUCOGTT: Areas under the curves for oral glucose tolerance test; SG: Sleeve gastrectomy; SG-LFD: SG rats with common low-fat diet; SG-HFD: SG with high-fat diet; DJB: Duodenal-jejunal bypass; DJB-LFD: DJB rats with LFD; DJB-HFD: DJB rats with HFD.

Figure 2 Homeostatic model assessment of insulin resistance of rats at baseline, 4 and 12 wk after operations. ^aP < 0.05 vs Sham group at 4 wk postoperatively; ^cP < 0.05 vs Sham group at 12 wk postoperatively; ^eP < 0.05 vs SG-HFD group at 4 wk postoperatively; ^gP < 0.05 vs DJB-HFD group at 4 wk postoperatively; ⁱP < 0.05 vs SG-LFD at 12 wk postoperatively; ^kP < 0.05 vs DJB-LFD at 12 wk postoperatively. HOMA-IR: Homeostatic model assessment of insulin resistance; SG: Sleeve gastrectomy; SG-LFD: SG rats with common low-fat diet; SG-HFD: SG with high-fat diet; DJB: Duodenal-jejunal bypass; DJB-LFD: DJB rats with LFD; DJB-HFD: DJB rats with HFD.

Figure 3 Western blot analysis of the insulin signaling pathway in liver and muscle. Expression of IR, IRS-1, IRS-2, PI3K, AKT in (A) liver and (B) muscle. A: SG-LFD group; B: SG-HFD group; C: DJB-LFD group; D: DJB-HFD group; E: Sham group. SG: Sleeve gastrectomy; SG-LFD: SG rats with common low-fat diet; SG-HFD: SG with high-fat diet; DJB: Duodenal-jejunal bypass; DJB-LFD: DJB rats with LFD; DJB-HFD: DJB rats with HFD.

Figure 4 Serum insulin after oral glucose administration. Serum insulin levels after oral glucose gavage (1 g/kg) at baseline (A), 4 (B) and 12 (C) wk postoperatively. No significant differences were observed in SG and DJB groups at 4 or 12 wk postoperatively. Insulin levels in response to oral glucose gavage increased in HFD and LFD rats at 12 wk postoperatively. ^aP < 0.05 vs Sham group at 12 wk postoperatively. SG: Sleeve gastrectomy; SG-LFD: SG rats with common low-fat diet; SG-HFD: SG with high-fat diet; DJB: Duodenal-jejunal bypass; DJB-LFD: DJB rats with LFD; DJB-HFD: DJB rats with HFD.

Figure 5 Pancreatic beta cell analysis. A: TUNEL-positive beta cell shown by immunofluorescence; B: and the percentage of TUNEL-positive beta cells was calculated. The two surgery group had fewer TUNEL-positive beta cells than the Sham group, and HFD group made the percentage higher than in the LFD group; C: The fluorescence intensity did not differ significantly between the four surgery groups (P > 0.05), but was higher than in the Sham group. ^aP < 0.05 vs Sham group at 12 wk postoperatively; ^cP < 0.05 vs SG-LFD group at 12 wk postoperatively; ^eP < 0.05 vs DJB-LFD group at 12 wk postoperatively. TUNEL: Transferase-mediated dUTP-biotin 3’ nick end-labeling; SG: Sleeve gastrectomy; SG-LFD: SG rats with common low-fat diet; SG-HFD: SG with high-fat diet; DJB: Duodenal-jejunal bypass; DJB-LFD: DJB rats with LFD; DJB-HFD: DJB rats with HFD.

Figure 6 Glucagon-like peptide-1, PYY, ghrelin levels. GLP-1 levels after oral glucose gavage (1 g/kg) at baseline (A), 4 (B) and 12 (C) weeks after surgery. PYY levels 1h after the oral glucose gavage (D). And the fasting ghrelin levels (E). ^aP < 0.05 vs Sham group at 4 wk postoperatively; ^cP < 0.05 vs Sham group at 12 wk postoperatively. SG: Sleeve gastrectomy; SG-LFD: SG rats with common low-fat diet; SG-HFD: SG with high-fat diet; DJB: Duodenal-jejunal bypass; DJB-LFD: DJB rats with LFD; DJB-HFD: DJB rats with HFD.