P189 Vascular ageing is apparent during an oral glucose challenge in healthy humans.

Background: In previous studies, we have demonstrated an impairment of endothelial-mediated vasodilatation during an oral glucose challenge (OGTT - 75 gram glucose over 1 min) measured by venous occlusive forearm plethysmography. These results appeared to be at odds with subsequent studies where we observed an increase rather than an impairment of vasodilatation. Since the population in the latter studies were substantially younger, we have investigated prospectively the extent of maximally stimulated endothelium-mediated forearm blood flow under an OGTT.Methods: We measure forearm blood flow (FBF) with venous occlusive plethysmography and assess endothelium-mediated vasodilation by intra-arterial infusion of increasing doses of serotonin and by flow-mediated vasodilation. Control for non-endothelium-mediated vasodilatation is measured with intra-arterial infusion of sodium nitroprusside. Measurements performed at baseline, one and two hours in an OGTT.Results (preliminary): All participants are healthy and grouped according to their age: a young group (n 8, range 20-26 years) and an older group (n 7, range 46-69 years). Maximal stimulated endothelium-mediated vasodilatation increased by 70% (SD 48%) one hour after initiation of OGTT compared to baseline stimulation in young individuals (p=0.03) while it decreased by 26% (SD 18%) in older volunteers. Two hours after OGTT initiation, FBF tended to resemble baseline response (FBF increased by 51%, SD 32% in young, and decreased by 69%, SD 19% in older). In one young person FBF was 4% lower after 1 h OGTT but increased by 18% after 2 hours. All of the older volunteers showed a fall in FBF during OGTT.Conclusion: Vascular ageing seems to be apparent in healthy individuals who undergo an oral glucose challenge. [ABSTRACT FROM PUBLISHER]