Effects of proximal and distal enteral glucose infusion on cardiovascular response in health and type 2 diabetes

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 evaluated the cardiovascular responses to proximal and distal small intestinal glucose infusion in health and T2DM. DESIGN: Double-blind, randomised, crossover design. SETTING: Single center in Australia. PATIENTS: 10 healthy subjects and 10 T2DM patients. INTERVENTIONS: Volunteers were studied on two occasions, when a transnasal catheter was positioned with infusion ports opening 13cm and 190cm beyond the pylorus. 30g glucose was infused into either site and 0.9% saline into the alternate site over 60min. MAIN OUTCOME MEASURES: BP, heart rate (HR) and superior mesenteric artery (SMA) blood flow were measured over 180min. RESULTS: Systolic BP was unchanged in response to both infusions in health, but decreased in T2DM, with a greater reduction after proximal vs. distal infusion (all P≤0.01). The increment in HR did not differ between treatments in health, but was greater after distal vs. proximal infusion in T2DM (P=0.02). The increases in SMA blood flow were initially greater, but less sustained, with proximal vs. distal infusion in health (P<0.001), 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.