Comparison of Glucostatic Parameters After Hypocaloric Diet or Bariatric Surgery and Equivalent Weight Loss

Abstract

Weight-loss independent mechanisms may play an important role in the improvement of glucose homeostasis after Roux-en-Y gastric bypass (RYGB). The objective of this analysis was to determine whether RYGB causes greater improvement in glucostatic parameters as compared with laparoscopic adjustable gastric banding (LAGB) or low calorie diet (LCD) after equivalent weight loss and independent of enteral nutrient passage. Study 1 recruited participants without type 2 diabetes mellitus (T2DM) who underwent LAGB (n = 8) or RYGB (n = 9). Study 2 recruited subjects with T2DM who underwent LCD (n = 7) or RYGB (n = 7). Insulin-supplemented frequently-sampled intravenous glucose tolerance test (fsIVGTT) was performed before and after equivalent weight reduction. MINMOD analysis of insulin sensitivity (Si), acute insulin response to glucose (AIRg) and C-peptide (ACPRg) response to glucose, and insulin secretion normalized to the degree of insulin resistance (disposition index (DI)) were analyzed. Weight loss was comparable in all groups (7.8 ± 0.4%). In Study 1, significant improvement of Si, ACPRg, and DI were observed only after LAGB. In Study 2, Si, ACPRg, and plasma adiponectin increased significantly in the RYGB-DM group but not in LCD. DI improved in both T2DM groups, but the absolute increase was greater after RYGB (258.2 ± 86.6 vs. 55.9 ± 19.9; P < 0.05). Antidiabetic medications were discontinued after RYGB contrasting with 55% reduction in the number of medications after LCD. No intervention affected fasting glucagon-like peptide (GLP)-1, peptide YY (PYY) or ghrelin levels. In conclusion, RYGB produced greater improvement in Si and DI compared with diet at equivalent weight loss in T2DM subjects. Such a beneficial effect was not observed in nondiabetic subjects at this early time-point.

Immediate enhancement of first-phase insulin secretion and unchanged glucose effectiveness in patients with type 2 diabetes after Roux-en-Y gastric bypass

“…However, in the longer-term, weight loss will improve insulin sensitivity in adipose tissue and decrease circulating free fatty acids, which may have additional beneficial effects on insulin secretion (4,14). In line with previous findings, we did not observe improved intrinsic ␤-cell function in normoglycemic individuals, whose ␤-cells by definition are not exposed to a glucotoxic environment, further supporting the proposed role of glucotoxicity (18,36,41,43,48,52). First-phase insulin secretion increased nonsignificantly in the IGT group.…”

“…A novel finding of the present study is the demonstration of an early enhancement of first-phase insulin secretion to iv glucose within 1 wk after surgery in patients with type 2 diabetes, before any major weight loss. Previous studies using IVGTTs have reported gradually increased first-phase insulin secretion in patients with type 2 diabetes in the first year after RYGB, attributed to weight loss (10,18,25,36,41,43,48,52). One study performed an IVGTT within the first week after RYGB and did not report significantly improved AIRg in patients with type 2 diabetes (48).…”

“…In light of this, it is interesting that the absolute GE is reduced in subjects with prediabetes or who manifest type 2 diabetes (2, 38) and appears to be regulated differentially from insulin sensitivity (32,53). In two studies, GE was reported unchanged 3 wk after RYGB in patients with type 2 diabetes and normal glucose tolerance (25,43). However, postoperative changes in GE may not be evident until months after surgery, when glucose levels have been normalized for a longer period.…”

Denervation of the Renal Arteries in Metabolic Syndrome

“…On the basis of available literature, 21 we expected a mean difference after treatment of 0.4±0.7. The desired power was set at 0.80, α (type I error) was set at 0.05.…”

“…Conforme a la literatura disponible, 21 se esperaba una diferencia promedio de 0,4 ± 0,7 después del tratamiento. La potencia deseada se fijó en 0,80, α (error tipo I)se fijó en 0,05.…”