Age-related changes in the kidney of patients with mild mesangial proliferative glomerulonephritis

In order to clarify age-related changes in kidneys, the renal function and histological changes were evaluated in 962 patients with mild mesangial proliferative glomerulonephritis (Mes PGN) whose ages ranged from 7 to 82 years. The glomerular filtration rate (GFR) (Ccr), renal plasma flow (RPF) (CPAH) and PSP excretion rate were significantly lower in nephritic patients than in normal subjects. Age-related decreases of GFR, RPF, PSP excretion rate and maximal urine specific gravity in Fishberg concentration test were found in both groups. Serum levels of creatinine, urea nitrogen and uric acid were significantly higher in nephritic patients than in the normal population. Age-related increases of those parameters were found in both groups. The incidence of sclerotic glomeruli was almost same as that of the normal population estimated by Kaplan et al. The incidence of arterio- and arteriolosclerosis was also higher than that of normal subjects estimated by Bell. Thus, arterio- and arteriolosclerosis seems to be more age-dependent than glomerulosclerosis in patients with mild Mes PGN. In conclusion, renal functions decrease and renal arteriolar lesions increase gradually in proportion to aging. Mes PGN, even mild, can accelerate the physiological age-related decrease of renal function.