Endogenous chronic hyperinsulinemia does not increase the production rate of VLDL apolipoprotein B: proof from a kinetic study in patients with insulinoma.
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Date publication
juillet 2011
Auteurs
Membres identifiés du Cancéropôle Est :
Pr PETIT Jean-Michel
Tous les auteurs :
Duvillard L, Florentin E, Pont F, Petit JM, Baillot-Rudoni S, Penfornis A, Verges B
Lien Pubmed
Résumé
OBJECTIVE: It is currently suggested that chronic hyperinsulinemia is a causal factor for the increased production rate of very-low-density lipoproteins (VLDL) associated with metabolic syndrome. However, the involvement of hyperinsulinemia independently of the other abnormalities also observed in metabolic syndrome has never been proven in humans. DESIGN: We used patients with insulinoma showing hyperinsulinemia but no insulin resistance as a model and conducted an apolipoprotein B (apoB) kinetic study in seven patients with insulinoma, seven insulin-resistant (IR) obese patients, and 12 controls. RESULTS: Insulinemia was higher in patients with insulinoma or IR than in controls both in the fasting state [2.4-fold (P = 0.039) and 3.1-fold (P = 0.003), respectively] and in the fed state [3.5-fold (P = 0.006) and 2.6-fold (P = 0.05), respectively]. Patients with insulinoma were not IR (steady state plasma glucose = 80 +/- 46 mg/dl, a value lower than in IR subjects (231 +/- 75, P = 0.0013). In the fed state, triglyceridemia and VLDL apoB pool size were higher in IR subjects compared with controls and patients with insulinoma [208 +/- 56 vs. 89 +/- 30 mg/dl (P < 0.0001) and 96 +/- 42 mg/dl (P < 0.0001), respectively, for triglyceridemia and 3.56 +/- 0.60 vs. 1.85 +/- 0.88 mg/kg (P = 0.004) and 2.32 +/- 1.79 (P = 0.052) mg/kg for VLDL apoB pool size]. The production rate of VLDL apoB in subjects with insulinoma was not significantly different from that in controls (14.56 +/- 7.43 vs. 16.40 +/- 7.70 mg/kg . d) but was higher in IR subjects compared with these two groups [25.66 +/- 12.84 mg/kg . d (P = 0.046 and 0.035, respectively)]. CONCLUSION: Chronic endogenous hyperinsulinemia is not directly responsible for any increase in the production rate of VLDL apoB in humans.
Référence
J Clin Endocrinol Metab. 2011 Jul;96(7):2163-70