A comparison of post-prandial changes in flow-mediated dilatation in patients with Type 2 diabetes with and without macroalbuminuria

During the post-prandial period there is a decrease in systemic vascular re sistance. This study compared meal-induced changes in flow-mediated dilatat ion (FMD) in patients with Type 2 diabetes with and without evidence of dia betic nephropathy as defined by the presence of macroalbuminuria. The effec ts on FMD of other factors such as smoking history, antihypertensive treatm ent and insulin use were also examined. Twelve patients with macroalbuminur ia (> 300 mg albumin/day) and 12 age- and sex-matched patients with normoal buminuria (< 50 mg albumin/day) participated in the study. Following a 12-h r overnight fast, forearm basal and reactive hyperaemic blood flow was asse ssed by venous occlusion plethysmography before and 2-hr after ingestion of a meal (2750 kJ) consisting of 56% fat, 26% carbohydrate and 16% protein. Plasma lipid and glycaemic indices were measured at the same times. The com bined and grouped data was analysed using paired t tests and correlation an d regression analyses. The meal resulted in significant increases in plasma glucose and triglyceride concentrations. While the meal resulted in a simi lar increase in basal blood flow rate in both patient groups, post-meal rea ctive hyperaemic flow increased significantly (p=0.04) in normoalbuminuric patients (mean individual increase: 33%) but remained unchanged in patients with macroalbuminuria (mean individual increase: 4%). The use of antihyper tensive agents and insulin was also associated with an attenuated post-pran dial hyperaemic response. In summary, our study demonstrated that the degre e of renal impairment in patients with T pe 2 diabetes may influence vasoac tivity following a meal. Patients with evidence of diabetic nephropathy had a decreased post-prandial hyperaemic response, a result that indicated a r educed vasodilator reserve. The mechanism of this reduction in vasodilatati on of peripheral vessels during the post-prandial period is probably multif actorial. These changes in vasoactivity have the potential to combine with other cardiovascular risk factors to enhance the development of atheroma. ( C) 2001, Editrice Kurtis.