Comparative renal histomorphometry: a case study of oligonephropathy of prematurity

Children born with very low birth weight have a decreased nephron number. Low nephron mass is associated with adult hypertension, proteinuria, and diabetes mellitus. The histomorphometry and radial glomerular count (RGC) of a total nephrectomy from a child with renal disease associated with extreme prematurity was compared with the kidney from a full-term age-matched child of normal gestation with chronic renal failure due to focal and segmental glomerulosclerosis (FSGS) and to a child without renal disease. Bowman’s space area, mesangium and mesangial tuft area were determined in 50 glomeruli of each specimen by computer-assisted morphometry. RGC was 4 in the ex-preterm child, 8 in the patient with FSGS, and 9 in normal control. The patient with FSGS had larger glomerular area expressed as square micrometers (μm²) of Bowman’s capsule, the mesangium and the mesangial tuft area measurements than the normal control and the child born preterm who subsequently developed renal failure had significantly larger Bowman’s capsule and mesangium than the two controls. This case report begins to identify important pathologic findings of decreased nephron numbers and glomerulomegaly associated with preterm birth.