Factors related to the glomerular size in renal biopsies of chronic kidney disease patients

Abstract

Glomerular enlargement is an important process that preserves the optimal surface area of glomerular capillaries under both physiological and pathological conditions. However, information is limited regarding how the glomerular size is defined, especially in chronic kidney disease (CKD) patients. A total of 206 renal biopsy specimens obtained from two different patient cohorts with or without a diagnosis of glomerulonephritis (non-GN group and IgAN group) were examined. The mean glomerular volume was estimated from the outer capillary area of individual glomeruli, and the clinicopathological factors at biopsy that were associated with the mean glomerular volume were analyzed in each group. The mean glomerular volume showed maximal 5.8 and 7.9-fold variations between individuals in the non-GN and IgAN groups, respectively. In both groups, the body mass index and glomerular density (non-sclerotic glomerular number per renal cortical area of the biopsy) were consistently identified as independent factors that were associated with the mean glomerular volume. In addition, the multivariate analyses using the glomerular density/body mass index ratio showed a more close association with the mean glomerular volume than the analyses using each measure separately. These results suggest that factors presumably reflecting both body consumption and nephron number have close relationships with the glomerular size, regardless of mechanism(s) underlying the injury. The most relevant factor affecting glomerular size may be a balance between these two measures.