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Differential associations between plasma concentrations of insulin and glucose and intestinal expression of key genes involved in chylomicron metabolism

Authors :
Patrick Couture
Jean-Philippe Drouin-Chartier
André J. Tremblay
Benoît Lamarche
Valéry Lemelin
Source :
American Journal of Physiology-Gastrointestinal and Liver Physiology. 315:G177-G184
Publication Year :
2018
Publisher :
American Physiological Society, 2018.

Abstract

The mechanisms underlying the oversecretion of apolipoprotein (apo)B-48-containing triglyceride-rich lipoproteins (TRL) in insulin-resistance (IR) states in humans remain to be fully understood. The objective of this study was to evaluate the association between the plasma levels of insulin and glucose and the intestinal expression of key genes involved in chylomicron metabolism in a large sample of nondiabetic men displaying various degrees of IR. Duodenal biopsies were obtained by gastroduodenoscopy in 127 men free of intestinal disease. Gene expression was measured using quantitative PCR in duodenal samples. Plasma insulin and glucose concentrations were measured in the fasting state. Postprandial TRL apoB-48 kinetics were measured using a primed-constant infusion of l-[5,5,5-D3]leucine for 12 h in a subgroup of 75 subjects maintained in a constant fed state. Plasma insulin levels were negatively associated with intestinal expression of ACS1 (standard β = −0.20, P = 0.007), DGAT1 (β = −0.18, P = 0.001), DGAT2 (β = −0.20, P = 0.02), and MTP (β = −0.27, P = 0.0005), whereas glucose levels were positively associated with MTP expression (β = 0.15, P = 0.04) independent of age, BMI, waist circumference, dietary intake, and duodenal expression of SREBP1c. Insulin levels, but not glucose concentrations, were positively correlated with postprandial TRL apoB-48 production rate ( r = 0.24, P = 0.04) and pool size ( r = 0.27, P = 0.03). In conclusion, plasma insulin and glucose levels are differentially associated with the expression of key genes involved in chylomicron metabolism. These results suggest that alterations in intestinal lipoprotein metabolism associated with IR may be regulated by plasma levels of both insulin and glucose concurrently and are therefore likely modified by the onset of insulin insufficiency.NEW & NOTEWORTHY We demonstrate that plasma insulin and glucose levels are differentially associated with the expression of key genes involved in chylomicron metabolism in men. For instance, intestinal expression of MTP is negatively associated with plasma insulin concentrations and positively associated with plasma glucose concentrations. Alterations in intestinal lipoprotein metabolism associated with insulin resistance may be regulated by plasma levels of both insulin and glucose concurrently and are therefore likely modified by the onset of insulin insufficiency.

Details

ISSN :
15221547 and 01931857
Volume :
315
Database :
OpenAIRE
Journal :
American Journal of Physiology-Gastrointestinal and Liver Physiology
Accession number :
edsair.doi.dedup.....3cbd1f039f1441428b185fbcc263d4fe
Full Text :
https://doi.org/10.1152/ajpgi.00108.2018