Endothelial dysfunction in type 2 diabetes.

The mechanisms responsible for the accelerated atherosclerosis observed in type 2 diabetes are not fully understood. One of the earliest events in the development of atherosclerosis is endothelial dysfunction, namely, a reduction in nitric oxide (NO) synthesis or its bioavailability within the peri-endothelial environment, where it is responsible for maintenance of vascular tissue integrity. The clinical evaluation of this pathway is hampered by the fact that in vivo NO cannot be directly measured; however, exploiting a novel, complex and elegant experimental setup, McVeigh and co-workers ( 1992;35:771-776) were the first to document that NO bioavailability in type 2 diabetic patients is indeed reduced. In this edition of 'Then and now' that paper is reappraised not only for its originality, but also for the broad and extensive evaluation of the vascular functions explored, the complete clinical characterisation of patients enrolled and for the fact that all the major findings were subsequently replicated.