Effects of Proximal and Distal Enteral Glucose Infusion on Cardiovascular Response in Health and Type 2 Diabetes

Abstract

Abstract Context Exposure of the small intestine to nutrients frequently leads to marked reductions in blood pressure (BP) in type 2 diabetes (T2DM). It remains unclear whether the region of the gut exposed to nutrients influences postprandial cardiovascular responses. Objective To evaluate the cardiovascular responses to proximal and distal small intestinal glucose infusion in health and T2DM. Design Double-blind, randomized, crossover design. Setting Single center in Australia. Patients 10 healthy subjects and 10 T2DM patients. Interventions Volunteers were studied on 2 occasions, when a transnasal catheter was positioned with infusion ports opening 13 cm and 190 cm beyond the pylorus. A 30-g bolus of glucose was infused into either site and 0.9% saline into the alternate site over 60 minutes. Main Outcome Measures BP, heart rate (HR), and superior mesenteric artery (SMA) blood flow were measured over 180 minutes. Results Systolic BP was unchanged in response to both infusions in health, but decreased in T2DM, with a greater reduction after proximal versus distal infusion (all P ≤ .01). The increment in HR did not differ between treatments in health, but was greater after distal versus proximal infusion in T2DM (P = .02). The increases in SMA blood flow were initially greater, but less sustained, with proximal versus distal infusion in health (P < .001), a pattern less evident in T2DM. Conclusions In T2DM, postprandial hypotension may be mitigated by diversion of nutrients from the proximal to the distal small intestine.