Abstract
Renal histology in patients with renal impairment associated with preterm and low birth weight infants is characterized by oligonephronia and focal segmental glomerulosclerosis (FSGS). Since its pathology is similar to that of mitochondrial (Mt) nephropathy, it is considered that an Mt disorder is involved in its pathogenesis. In this study, Staining with COX4 and mitochondrial transcription factor A (TFAM) in renal tissue were performed in 8 preterm cases with a low birth weight, and the relationship with the clinical features was examined. The mean urinary protein, Cr, and Cystatin-C were 0.67 g/gCr, 0.82 mg/dl, and 1.12 mg/L, respectively. In renal tissue, the average number of glomeruli was 3.2/mm2, and in 5 cases, the glomeruli showed minimal change. FSGS was observed in 4 cases. Granular swollen epithelial cells suggesting an Mt disorder was observed in renal tubular epithelial cells in 7 cases, and staining for COX4 exhibited a mosaic pattern at the same site. TFAM expression was low in one case with a moderate tubular interstitial injury. Electron microscopy revealed swelling of the glomerular epithelial cells accompanied by an accumulation of abnormal Mt, in which cristae disappeared in 6 cases. This study suggested that an Mt abnormality may have been involved in renal injuries in low birth weight infants.
