Glomerular size and glomerulosclerosis in Australian Aborigines

We have previously described the prevalence of glomerulomegaly in biopsy sp ecimens from Australian Aborigines with renal disease, a phenomenon documen ted in a number of other indigenous populations. Many of the biopsy specime ns showed variable degrees of focal and segmental glomerulosclerosis (FSGS) . Correlations between glomerular size and FSGS have been described in vari ous animal models, as well as studies of humans. The aim of this study is t o determine whether a relation exists between glomerular volume and severit y of FSGS in biopsy specimens from Australian Aboriginals in the Northern T erritory and Aboriginal inhabitants of the Tiwi Islands (Bathurst Island an d Melville Island, Northern Territory, Australia). Consecutive clinical bio psy specimens were obtained from 78 non-Tiwi and 72 Tiwi Aboriginals. Glome rular volume was estimated using the stereological method of Weibel and Gom ez, FSGS was graded from 0 to 4; 0 indicates no sclerosis and 4 indicates s evere sclerosis, A biphasic relationship between glomerular size and severi ty of FSGS was identified. As the severity of FSGS increased from grade 0 t o grade 3, glomerular size also increased. For both populations studied, gl omeruli scored as grades 1,2, and 3 were approximately 50% (P < 0.001), 65% (P < 0.001), and 100% (P < 0.001) larger than normal glomeruli, respective ly. However, in glomeruli with grade 4 FSGS, glomerular size decreased to t he size of normal glomeruli, These results show a biphasic relationship bet ween severity of FSGS and glomerular size in Australian Aborigines. (C) 200 0 by the National Kidney Foundation, Inc.