Endothelial cells are directly exposed to altered concentrations of circulating metabolites in diabetes and are likely to be involved early, if not primarily, in the natural history of the chronic complications of the disease. Thus, better understanding of the mechanisms underlying endothelial dysfunction and of their possible pathogenetic relevance might help to establish a rationale on which to base prospective trials for the prevention or treatment of microangiopathy.
A word of caution should be made in warning that most data available today are derived from experiments in vitro or carried out under highly perturbed conditions in vivo and that virtually none of the methods employed has so far been standardised among different laboratories. Hence, it should come as no surprise if some results are in conflict with each other or will be refuted in the near future. Work on endothelium has only just begun and much still has to be done in this fascinating field of investigation.