HUMAN ATRIAL-NATRIURETIC-PEPTIDE IN PATIENTS WITH TYPE-1 DIABETES-MELLITUS - IS IT RELATED TO THE DEVELOPMENT OF DIABETIC NEPHROPATHY

There is controversy as to whether increased plasma levels of human at rial natriuretic peptide (hANP) in patients with type 1 diabetes melli tus may contribute to the development of diabetic nephropathy. Therefo re, we decided to conduct two studies to examine the relationship of h ANP levels to urinary albumin excretion and blood pressure. In a cross -sectional study, 83 randomly selected type 1 diabetic patients were i nvestigated. 19 of the patients had increased urinary albumin excretio n. 45 healthy volunteers served as controls. In a longitudinal study, 19 type 1 diabetic patients were examined for one year at monthly inte rvals. An increased risk of eventually developing diabetic nephropathy was identified in 7 out of these patients by repeatedly revealing inc reased urinary albumin excretion. On the average, hANP levels were inc reased in type 1 diabetic patients in comparison to controls (P<0.001) . In both studies, hANP levels were positively related (P<0.05) to mea n arterial blood pressure. There was no correlation between hANP level s and metabolic control. hANP levels lay within normal range irrespect ive of normal or elevated urinary albumin excretion provided that mean arterial blood pressure was normal. In the longitudinal study, increa sed urinary albumin and alpha-1-microglobulin excretion preceded the i ncrease in both hANP levels and mean arterial blood pressure. Although hANP levels were evidently not related to the disease mechanisms of e arly diabetic nephropathy, it is tempting to speculate that hANP may c ontribute to the vicious circle connecting diabetic kidney disease to hypertension once that its levels are increased by elevated blood pres sure.