Hyperinsulinemic hypoglycemia after gastric bypass surgery is not accompanied by islet hyperplasia or increased beta-cell turnover.

Abstract

OBJECTIVE:

The purpose of this study was to establish whether hypoglycemia after gastric bypass surgery (GBS) for morbid obesity is due to increased fractional beta-cell area or inappropriately increased insulin secretion.

RESEARCH DESIGN AND METHODS:

We examined pancreata obtained at partial pancreatectomy from 6 patients with post-GBS hypoglycemia and compared these with 31 pancreata from obese subjects and 16 pancreata from lean control subjects obtained at autopsy. We addressed the following questions. In patients with post-GBS hypoglycemia, is beta-cell area increased and is beta-cell formation increased or beta-cell apoptosis decreased?

RESULTS:

We report that in patients with post-GBS hypoglycemia, beta-cell area was not increased compared with that in obese or even lean control subjects. Consistent with this finding, there was no evidence of increased beta-cell formation (islet neogenesis and beta-cell replication) or decreased beta-cell loss in patients with post-GBS hypoglycemia. In control subjects, mean beta-cell nuclear diameter correlated with BMI (r(2) = 0.79, P < 0.001). In patients with post-GBS hypoglycemia, beta-cell nuclear diameter was increased (P < 0.001) compared with that for BMI in matched control subjects but was appropriate for BMI before surgery.

CONCLUSIONS:

We conclude that post-GBS hypoglycemia is not due to increases in beta-cell mass or formation. Rather, postprandial hypoglycemia after GBS is due to a combination of gastric dumping and inappropriately increased insulin secretion, either as a failure to adaptively decrease insulin secretion after GBS or as an acquired phenomenon.

• Authors: Juris J Meier, Alexandra E Butler, Ryan Galasso, Peter C Butler
• Journal: Diabetes care (Diabetes Care) Vol. 29 Issue 7 Pg. 1554-9 (Jul 2006) ISSN: 0149-5992 [Print] United States
• PMID: 16801578 (Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't)

Chemical References

• Insulin

Topics

• Adult
• Body Mass Index
• Cell Nucleus (ultrastructure)
• Cell Size
• Dumping Syndrome (etiology)
• Female
• Gastric Bypass (adverse effects)
• Humans
• Hyperinsulinism (etiology)
• Hyperplasia
• Hypoglycemia (etiology)
• Insulin (metabolism)
• Insulin Secretion
• Insulin-Secreting Cells (cytology)
• Islets of Langerhans (pathology)
• Male
• Middle Aged
• Obesity, Morbid (surgery)