Antihypertensive therapy and diabetic microvascular disease.

Hypertension is commonly associated with diabetes and may represent either a manifestation or a cause of diabetic vascular injury. The following series of studies have explored the role of hypertension in accelerating diabetic microvascular injury. In addition, the role of various classes of antihypertensive agents in preventing or reversing diabetic vascular abnormalities in the presence and absence of systemic hypertension was assessed in both the experimental and clinical context. The induction of streptozotocin diabetes in SHR leads to accelerated development of nephropathy as assessed by both functional and structural parameters. ACE inhibitors but not dihydropyridine calcium channel blockers favourably influence the progression of experimental diabetic nephropathy even in the setting of a normal blood pressure. More recent studies have shown that the trophic changes in the mesenteric arteries from diabetic rats are also attenuated by ACE inhibition. Preliminary results from the Melbourne Diabetic Nephropathy Study Group suggest that the ACE inhibitor, perindopril, is more effective than the dihydropyridine calcium channel blocker, nifedipine, in retarding the rise in urinary albumin excretion in normotensive insulin and noninsulin dependent diabetic patients with microalbuminuria. In conclusion, ACE inhibitors appear to be the drugs of choice in prevention and treatment of diabetic renal disease and may also act as protective agents at other sites of vascular injury.