GLOMERULAR ENLARGEMENT IN THE PROGRESSION OF MESANGIAL PROLIFERATIVE GLOMERULONEPHRITIS

A close association between glomerular hypertrophy and subsequent scle rosis has been demonstrated in diverse animal and human studies. We in vestigated the relationship between the glomerular volume and glomerul ar constituents (mesangial matrix, mesangial cells and capillary lumen s) in human mesangial proliferative glomerulonephritis (GN). The data were obtained from glomeruli in the specimens of 23 patients undergoin g repeat renal biopsies. Glomerular volume and glomerular constituents of each patient were obtained by averaging those of all glomeruli in each specimen. The interval from the first biopsy to the second was 51 .2 +/- 6.8 months and the number of glomeruli included in each specime n was 16 +/- 1. Between glomerular volume and fractional mesangial vol ume, three patterns were recognized. In 8 of 23 patients glomerular vo lume and fractional mesangial volume were increased in the second biop sy (Group A). In 12 of 23 patients glomerular volume was decreased and fractional mesangial volume increased in the second biopsy (Group B), and in 3 of 23 patients glomerular volume was increased and fractiona l mesangial volume decreased in the second biopsy (Group C). One patie nt who underwent renal biopsy three times shifted from Group A to Grou p B in the course of mesangial proliferative GN. At the final follow-u p, 4 of 12 patients in Group B required hemodialysis in contrast to no ne of 8 patients in Group A. Between glomerular volume and fractional mesangial volume, a positive and inverse relation existed, and we cons idered that in the course of mesangial proliferative GN, initially, gl omerular size increases and thereafter decreases progressively. With g lomerular enlargement, mesangial matrix expansion, glomerular capillar y enlargement and relative decrease of the number of capillary lumen p rofiles and mesangial cells per glomerulus to increased glomerular vol ume were recognized. We concluded that these histological changes play a role in the progression of mesangial proliferative GN in humans as has been speculated in animal models of renal ablation.