Urinary excretions of albumin and type IV collagen in normotensive and hypertensive subjects

Plasma albumin leaks into urine as a result of glomerular hypertension and basement membrane injury, while urinary type IV collagen derives from mesan gial matrix and glomerular basement membrane. The purpose of this study was to elucidate the pathophysiological significance of these urinary micropro teins as an indicator of cardiovascular organ injuries in hypertension, In health-checkup participants without diabetes, proteinuria, or microhematuri a, and who were not being treated for hypertension or any other disease at the time of enrollment, urinary albumin and type IV collagen were measured and their relations to organ injuries and cardiovascular risk factors were evaluated, Of 1,079 subjects (40- to 65-year-old; 256 men and 823 women) en rolled in the study, 120 (11.1%) had untreated hypertension exceeding 140/9 0 mmHg, Urinary albumin was positively correlated with both age (r=0.16, p< 0.001) and systolic blood pressure (r=0.27, p<0.001). Urinary type IV colla gen was not only positively correlated with age (r=0.12, p<0.001) and diast olic blood pressure (r=0.14, p<0.001) but also negatively correlated with b lood hemoglobin (r=-0.12, p<0.001). Urinary albumin, but not type IV collag en, had a significant relation to electro cardiographic signs of left ventr icular hypertrophy (p=0.012) and retinal arteriosclerosis on fundoscopy (p <0.001). Thus both albumin and type IV collagen would seem to have increase d in association with age and hypertension in this cohort. It is suggested that urinary albumin is an indicator not only of renal injury, but also pos sibly of development of cardiac hypertrophy and arteriosclerotic changes. U rinary type IV collagen, on the other hand, may be associated with renal ti ssue injuries that affect erythrokinetics.