Research Paper Volume 12, Issue 17 pp 17601—17624

Parietal epithelial cell differentiation to a podocyte fate in the aged mouse kidney

Figure 1. Glomerulosclerosis in aged PEC-PODO reporter mice. (AF) Representative images of p57 stained (brown, nuclear) podocytes with periodic acid–Schiff staining (PAS) counterstaining from young (6 months) (A, B), middle age (14 months) (C, D) and aged (24 months) (E, F) mice. Glomeruli were divided into two compartments: outer cortex (OC) (A, C, E) and juxta-medullary cortex (JMC) (B, D, F). Small insets represent examples of OC glomeruli (E1E4) and JMC glomeruli (F1F4) for each scoring category that characterized the severity of injury: starting from 0 (no injury) to 3 (globally sclerotic glomeruli). (G) Graph of glomerular injury scores in OC. The highest percentage of uninjured glomeruli (score 0) was in young mice (black bars). Middle age mice (gray bars) showed a significantly higher percentage of injured glomeruli (score- 1, 2) and increase in the severity of injury (score-3). Aged mice (white bars) showed a significantly higher percentage of injured glomeruli (score-1,2), and an increase in the severity of injury (score-3) compared to young and middle age mice, while the percentage of uninjured glomeruli was significantly decreased in aged versus young and middle age mice. (H) Graph of glomerular injury scores in the JMC. The percentage of injured glomeruli (score-1, 2) was significantly higher in aged mice (white bars) compared to middle age (gray bars) and young (black bars) mice. The percentage of severely injured glomeruli (score-3) was increased but did not reach statistical significance. Middle age mice showed a significant increase in injured (score-1,2) and severely injured glomeruli (score-3) compared young mice. (I) Quantification of podocyte number in the OC. Podocyte number per cross section, identified by p57+ cells, showed a decreasing trend for middle age and aged mice compared to young mice for individual injury scores, but the differences were not statistically significant. Podocyte number was significantly lower for injured glomeruli (score-1,2,3) compared to uninjured glomeruli (score-0). (J) Quantification of podocyte number in the JMC. Podocyte number per cross section, identified by p57+cells was higher compared to OC and showed a trend decreasing trend for middle age and aged mice compared to young mice for individual injury scores, but the differences were not statistically significant. Podocyte number was significantly lower for injured glomeruli (score-1,2,3) compared to uninjured glomeruli (score-0).