Polycythemia, capillary rarefaction, and focal glomerulosclerosis in two adolescents born extremely low birth weight and premature

Nariaki Asada, Takanori Tsukahara, Megumi Furuhata, Daisuke Matsuoka, Shunsuke Noda, Kuniaki Naganuma, Akinori Hashiguchi, Midori Awazu

Research output: Contribution to journalArticlepeer-review

11 Citations (Scopus)


Background: Low birthweight infants have a reduced number of nephrons and are at high risk of chronic kidney disease. Preterm birth and/or intrauterine growth restriction (IUGR) may also affect peritubular capillary development, as has been shown in other organs. Case-Diagnosis/Treatment: We report two patients with a history of preterm birth and extremely low birthweight who showed polycythemia and renal capillary rarefaction. Patient 1 and 2, born at 25 weeks of gestation with a birthweight of 728 and 466 g, showed mild proteinuria at age 8 and 6 years, respectively. In addition to increasing proteinuria, hemoglobin levels became elevated towards adolescence and their serum erythropoietin (EPO) was high despite polycythemia. Light microscopic examination of renal biopsy specimens showed glomerular hypertrophy, focal segmental glomerulosclerosis, and only mild tubulointerstitial fibrosis. A decrease in the immunohistochemical staining of CD31 and CD34 endothelial cells in renal biopsy specimens was consistent with peritubular capillary rarefaction. Conclusions: Since kidney function was almost normal and fibrosis was not severe, we consider that the capillary rarefaction and polycythemia associated with elevated EPO levels were largely attributable to preterm birth and/or IUGR.

Original languageEnglish
Pages (from-to)1275-1278
Number of pages4
JournalPediatric Nephrology
Issue number7
Publication statusPublished - 2017 Jul 1


  • Erythropoietin
  • Focal segmental glomerulosclerosis
  • Low birth weight
  • Polycythemia
  • Preterm birth

ASJC Scopus subject areas

  • Pediatrics, Perinatology, and Child Health
  • Nephrology


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