Relationship among nephron number, cortical volume, and glomerular pressure in healthy kidney donors

Glomerular hypertension is a critical factor in kidney disease progression. Traditionally, nephron number (Nglom) was considered a determinant of glomerular hemodynamics, but emerging evidence suggests a more substantial impact of renal structural factors. This cross-sectional study aimed to evaluate the relationship between renal histopathological parameters and intraglomerular hydrostatic pressure (Pglo) in healthy donors. Retrospective analyses were conducted on 60 healthy living donors who donated a kidney between January 1, 2007, and September 30, 2022. The non-sclerotic glomerular number (Nglom_NSG), glomerular volume, cortical volume, and other histopathological parameters were evaluated. Pglo was estimated using Gomez's equation. Pglo was positively associated with cortical volume (standardized regression coefficient [β] = 0.34, p = 0.04) but not with Nglom_NSG (β = 0.12, p = 0.44). Cortical volume was inversely associated with afferent arteriolar resistance (β = -0.33, p < 0.01). These findings suggest that an increase in cortical volume, independent of nephron number, may contribute to an increase in Pglo through a reduction in afferent arteriolar resistance. These results refine current models of glomerular hemodynamics, highlighting the importance of structural renal evaluation, including cortical volume, in assessing early chronic kidney disease risk.