Distribution of glomerular density in different cortical zones of the human kidney


Correspondence: Go Kanzaki, MD, Division of Kidney and Hypertension, Department of Internal Medicine, The Jikei University School of Medicine, 3-25-8 Nishi-Shimbashi, Minato-Ku, Tokyo, Japan. Email: g-kanzaki@jikei.ac.jp


Our studies have demonstrated that a low glomerular density in renal biopsies is a plausible predictor of a worse renal outcome in patients with primary glomerular diseases. However, there remains a concern regarding the diversity that may exist in the distribution of glomerular density within the same kidney. This study therefore aimed to determine the differences in the glomerular density between anatomically different cortical zones of the human kidney. A total of 89 autopsy kidneys were analyzed to accurately measure the glomerular density in different parts of the renal cortex. As a whole, compared to the glomerular density in the superficial cortex (3.0 ± 0.7/mm2), the average glomerular density in the juxtamedullary cortex (2.2 ± 0.6/mm2) was approximately two-thirds. The glomerular density showed maximal 3.5-fold variations between individuals and was inversely correlated with the mean glomerular volume in both cortical areas. A low glomerular density of the superficial cortex was predominantly associated with the increase of global glomerulosclerosis. On the other hand, a low glomerular density of the juxtamedullary cortex was predominantly associated with an increase in the kidney weight. Thus, there are significant zonal differences in the distribution of the glomerular density in human kidneys independent of the potential variations observed between individuals.