One-hour post-load hyperglycemia combined with HbA1c identifies individuals with augmented duodenal levels of sodium/glucose co-transporter 1

Obesity and overweight are linked to increased sodium-glucose cotransporter 1 and glucose transporter 5 levels in duodenum

OBJECTIVE

Prior evidence indicates that individuals with obesity have an accelerated intestinal glucose absorption. This cross-sectional study evaluated whether those with overweight or obesity display higher duodenal protein levels of the glucose carriers sodium-glucose cotransporter 1 (SGLT-1), glucose transporter 2 (GLUT-2), and glucose transporter 5 (GLUT-5).

METHODS

SGLT-1, GLUT-2, and GLUT-5 protein levels were assessed on duodenal mucosa biopsies of 52 individuals without diabetes categorized on the basis of their BMI as lean, with overweight, or with obesity.

RESULTS

Individuals with overweight and obesity exhibited progressively increased duodenal protein levels of SGLT-1 and GLUT-5 as compared with the lean group. Conversely, no differences in duodenal GLUT-2 abundance were found among the three groups. Univariate analysis showed that SGLT-1 and GLUT-5 protein levels were positively correlated with BMI, waist circumference, 1-hour post-load glucose, fasting and post-load insulin, and insulin secretion and resistance levels. Furthermore, a positive relationship was detected between intestinal GLUT-5 levels and serum uric acid concentrations, a product of fructose metabolism known to be involved in the pathogenesis of obesity and its complications.

CONCLUSIONS

Individuals with overweight and obesity display enhanced duodenal SGLT-1 and GLUT-5 abundance, which correlates with increased postprandial glucose concentrations, insulin resistance, and hyperinsulinemia.

Peptide Tyrosine-Tyrosine Triggers GLP-2-Mediated Intestinal Hypertrophy After Roux-en-Y Gastric Bypass

Purpose 

Intestinal remodeling and adaptation of the alimentary limb after Roux-en-Y gastric bypass (RYGB) play an important role in the pathophysiological events that lead to type 2 diabetes mellitus (T2DM) improvement. Intestinal absorptive loop hypertrophy and growth following surgery have been related to GLP-2 secretion by ileal L-cells. The secretion of peptide tyrosine-tyrosine (PYY) enterohormone after a meal has been proposed as a trigger for ileal secretion of GLP-1. Our aim is to determine the role of PYY as a GLP-2 secretion modulator as an adaptation result in the alimentary limb after RYGB.

Method

We used a non-obese euglycemic rodent model. Circulating glucose, insulin, PYY, and GLP-2 were measured in the experimental and control groups. We used four groups: fasting control, Sham-operated, RYGB-operated (RYGB), and RYGB-operated and treated with BIIE0246 (RYGB + BII). BIIE0246 is a NPY2 receptor antagonist in L-cells. Intestinal glucose transporters and GLP-1 and PYY gut expression and hypertrophy were analyzed after 12 weeks of surgery.

Results

RYGB increased PYY3-36 plasma levels in rats with or without BII treatment. A high-insulin response was observed in the RYGB group but not in the control or RYGB + BII groups. BIIE0246 treatment limited plasma GLP-2 levels. In the alimentary intestinal limb, hypertrophy and SGLT1 and GLUT1 expression appeared to be reduced after RYGB compared to controls.

Conclusion

The postprandial ileal PYY secretion is enhanced after RYGB. This increase mediates GLP-2 release through its binding to the Y2 receptor on L-cells. This mechanism plays a role in alimentary limb hypertrophy after surgery.

Graphical abstract

Augmented duodenal levels of sodium/glucose co-transporter 1 are associated with higher risk of nonalcoholic fatty liver disease and noninvasive index of liver fibrosis

AIMS

Subjects with elevated 1 h post-load glucose concentrations (1hPG) exhibit increased risk of non-alcoholic fatty liver disease (NAFLD) and duodenal sodium/glucose co-transporter 1 (SGLT-1) levels. Herein, we evaluate whether higher SGLT-1 duodenal levels are associated with NAFLD and increased risk of advance liver fibrosis.

METHODS

SGLT-1 levels were assessed on duodenal mucosa in 52 individuals subdivided into two groups according to ultrasonography-defined presence of NAFLD. Intracellular triglycerides levels and activation of endoplasmic reticulum (ER) stress were evaluated in human hepatocytes exposed to high-glucose concentration (HG).

RESULTS

Individuals with NAFLD exhibited higher duodenal SGLT-1 abundance along with raised 1hPG, as compared to those without NAFLD. The mediation analysis showed that augmented duodenal SGLT-1 levels were a predictor of NAFLD, and the link between increased duodenal SGLT-1 content and NAFLD risk was mediated by augmented 1hPG. Amongst participants with NAFLD, those with intermediate/high probability of advance liver fibrosis, estimated by NAFLD fibrosis score, exhibited higher duodenal SGLT-1 abundance and 1hPG levels as compared to the low probability group. Hepatocytes exposed to HG showed increased triglycerides accumulation and an up-regulation of ER stress pathway.

CONCLUSIONS

Increased duodenal SGLT-1 abundance and the related early post-prandial hyperglycemia are associated with NAFLD and advance liver fibrosis.