Effects of acute NEFA manipulation on incretin-induced insulin secretion in participants with and without type 2 diabetes.

Abstract

AIMS/HYPOTHESIS:

Incretin effect-the potentiation of glucose-stimulated insulin release induced by the oral vs the i.v. route-is impaired in dysglycaemic states. Despite evidence from human islet studies that NEFA interfere with incretin function, little information is available about the effect in humans. We tested the impact of acute bidirectional NEFA manipulation on the incretin effect in humans.

METHODS:

Thirteen individuals with type 2 diabetes and ten non-diabetic volunteers had a 3 h OGTT, and, a week later, an i.v. isoglycaemic glucose infusion (ISO; OGTT matched). Both pairs of studies were repeated during an exogenous lipid infusion in the non-diabetic volunteers, and following acipimox administration (to inhibit lipolysis) in people with diabetes. Mathematical modelling of insulin secretion dynamics assessed total insulin secretion (TIS), beta cell glucose sensitivity (β-GS), glucose-induced potentiation (PGLU) and incretin-induced potentiation (PINCR); the oral glucose sensitivity index was used to estimate insulin sensitivity.

RESULTS:

Lipid infusion increased TIS (from 61 [interquartile range 26] to 78 [31] nmol/m2 on OGTT and from 29 nmol/m2 [26] to 57 nmol/m2 [30] on ISO) and induced insulin resistance. PINCR decreased from 1.6 [1.1] to 1.3 [0.1] (p < 0.05). β-GS, PGLU and glucagon, glucagon-like peptide 1 (GLP-1) and gastric inhibitory polypeptide (GIP) responses were unaffected. Acipimox (lowering NEFA by ~55%) reduced plasma glucose and TIS and enhanced insulin sensitivity, but did not change β-GS, PINCR, PGLU or glucagon, GLP-1 or GIP responses. As the per cent difference, incretin effect was decreased in non-diabetic participants and unchanged in those with diabetes.

CONCLUSIONS/INTERPRETATION:

Raising NEFA selectively impairs incretin effect and insulin sensitivity in non-diabetic individuals, while acute NEFA reduction lowers plasma glucose and enhances insulin sensitivity in people with diabetes but does not correct the impaired incretin-induced potentiation.

• Authors: Brenno Astiarraga, Valéria B Chueire, Aglécio L Souza, Ricardo Pereira-Moreira, Sarah Monte Alegre, Andrea Natali, Andrea Tura, Andrea Mari, Ele Ferrannini, Elza Muscelli
• Journal: Diabetologia (Diabetologia) Vol. 61 Issue 8 Pg. 1829-1837 (08 2018) ISSN: 1432-0428 [Electronic] Germany
• PMID: 29732475 (Publication Type: Journal Article, Multicenter Study, Research Support, Non-U.S. Gov't)

Chemical References

• Blood Glucose
• Fatty Acids, Nonesterified
• Incretins
• Insulin
• Lipids
• Pyrazines
• Gastric Inhibitory Polypeptide
• Glucagon-Like Peptide 1
• Glucagon
• acipimox

Topics

• Adolescent
• Adult
• Blood Glucose (analysis)
• Diabetes Mellitus, Type 2 (metabolism, pathology)
• Fatty Acids, Nonesterified (metabolism)
• Gastric Inhibitory Polypeptide (blood)
• Glucagon (blood)
• Glucagon-Like Peptide 1 (blood)
• Glucose Tolerance Test
• Humans
• Incretins (metabolism)
• Insulin (metabolism)
• Insulin-Secreting Cells (metabolism)
• Lipids (chemistry)
• Middle Aged
• Pyrazines (pharmacology)
• Time Factors
• Young Adult