CHU Bichat Claude Bernard, AP-HP, Service de Diabétologie-Endocrinologie-Nutrition,75877 Paris cedex 18, France.
Diabetes Metab. 2009 Dec;35(6 Pt 2):499-507. doi: 10.1016/S1262-3636(09)73456-1.
Bariatric surgery is indicated in cases of severe obesity. However, malabsorption-based techniques (gastric bypass and biliopancreatic diversion, both of which exclude the duodenum and jejunum from the alimentary circuit), but not restrictive techniques, can abolish type 2 diabetes within days of surgery, even before any significant weight loss has occurred. This means that calorie restriction alone cannot entirely account for this effect. In Goto-Kakizaki rats, a type 2 diabetes model, glycaemic equilibrium is improved by surgical exclusion of the proximal intestine, but deteriorates again when the proximal intestine is reconnected to the circuit in the same animals. This effect is independent of weight, suggesting that the intestine is itself involved in the immediate regulation of carbohydrate homoeostasis. In humans, the rapid improvement in carbohydrate homoeostasis observed after bypass surgery is secondary to an increase in insulin sensitivity rather than an increase in insulin secretion, which occurs later. Several mechanisms are involved--disappearance of hypertriglyceridaemia and decrease in levels of circulating fatty acids, disappearance of the mechanisms of lipotoxicity in the liver and skeletal muscle, and increases in secretion of GLP-1 and PYY--and may be intricately linked. In the medium term and in parallel with weight loss, a decrease in fatty tissue inflammation (which is also seen with restrictive techniques) may also be involved in metabolic improvement. Other mechanisms specific to malabsorption-based techniques (due to the required exclusion of part of the intestine), such as changes in the activity of digestive vagal afferents, changes in intestinal flora and stimulation of intestinal neoglucogenesis, also need to be studied in greater detail. The intestine is, thus, a key organ in the regulation of glycaemic equilibrium and may even be involved in the pathophysiology of type 2 diabetes.
肥胖症患者需要进行减重手术。然而，基于吸收不良的技术（胃旁路和胆胰分流术，两者均将十二指肠和空肠从消化道中排除），而不是限制技术，可以在手术几天后甚至在体重显著减轻之前消除 2 型糖尿病。这意味着单纯的热量限制并不能完全解释这种效果。在 Goto-Kakizaki 大鼠（2 型糖尿病模型）中，通过手术排除近端肠来改善血糖平衡，但在同一动物中将近端肠重新连接到回路中时，这种效果又会恶化。这种效果与体重无关，表明肠道本身参与了碳水化合物平衡的即时调节。在人类中，旁路手术后观察到的碳水化合物平衡的快速改善是由于胰岛素敏感性的增加而不是胰岛素分泌的增加所致，后者发生在后。涉及到几种机制——高甘油三酯血症的消失和循环脂肪酸水平的降低、肝脏和骨骼肌中脂毒性机制的消失以及 GLP-1 和 PYY 的分泌增加——并且可能错综复杂地联系在一起。从中期来看，与体重减轻并行，脂肪组织炎症的减少（也见于限制技术）也可能与代谢改善有关。其他特定于基于吸收不良的技术的机制（由于需要排除部分肠道），例如消化性迷走传入活动的变化、肠道菌群的变化和肠道新生葡萄糖生成的刺激，也需要更详细地研究。因此，肠道是调节血糖平衡的关键器官，甚至可能参与 2 型糖尿病的病理生理学。
