Peptide tyrosine-tyrosine triggers GLP-2-mediated intestinal hypertrophy after Roux en-Y gastric bypass.

Abstract

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 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. To this, we used a nonobese 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 twelve weeks of surgery. 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 the other groups. We concluded that 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.