Albuminuria in patients with type 1 diabetes is directly linked to changes in the lysosome-mediated degradation of albumin during renal passage

Abstract

Previous studies by our group have shown that albumin is metabolized in rodents during renal passage and excreted in the urine as a mixture of intact protein and albumin-derived fragments. The aim of this study was to examine whether albumin is metabolized during renal passage in nondiabetic volunteers and in type 1 diabetic patients with varying levels of albuminuria. Nine nondiabetic normoalbuminuric volunteers and 11 type 1 diabetic patients with albumin excretion rates varying from normoalbuminuria to macroalbuminuria were studied. Each subject received an intravenous injection of tritium-labeled albumin ([3H]-albumin). Urine was collected at 4 h and 24 h after injection and analyzed by ..