Low birthweight and premature birth are risk factors for podocytopenia and focal segmental glomerulosclerosis.
BACKGROUND
Recent reports suggest that low birthweight (LBW) is a risk factor for kidney diseases, including focal segmental glomerulosclerosis (FSGS), although the underlying pathological mechanism remains unknown. Podocyte loss triggers glomerulosclerosis; however, whether FSGS in LBW children is associated with podocytopenia is unclear.


METHODS
We reviewed the birthweights and gestational age of all patients who underwent renal biopsies from 1995 to 2011 at our Institute. Sixteen patients had FSGS, of which 6 (37.5%) had LBW; this LBW rate was significantly higher than the overall LBW rate in Japan (9.7%). The incidence of LBW was also high in patients with minimal change nephrotic syndrome (MCNS; 12.5%). The glomerular cell numbers in biopsy sections were calculated using computer image analysis and compared with FSGS of normal birthweight (NBW-FSGS). Biopsy specimens from age-matched patients with MCNS were also compared. Wilms' tumor-1 (WT1) immunohistochemistry was performed to enumerate the podocytes.


RESULTS
All patients in the LBW-FSGS group were also preterm, with an average gestational age of 25.8 weeks. The number of podocytes per glomerulus in the LBW-FSGS patients was 34 and 24% lower as compared to that in the MCNS patients (p < 0.01) and the NBW-FSGS patients (p < 0.05), respectively. Similar results were observed for the WT1-positive glomerular cell number.


CONCLUSIONS
LBW and premature birth were associated with FSGS development. The possibility that LBW and premature birth may be predisposing factors for severe podocytopenia in children with FSGS warrants further investigation.
Department of Pediatrics, Niigata University Medical and Dental Hospital, Niigata, Japan. ikezumi@med.niigata-u.ac.jp
Yohei
Y
Ikezumi
Toshiaki
T
Suzuki
Tamaki
T
Karasawa
Takeshi
T
Yamada
Hiroya
H
Hasegawa
Hiroko
H
Nishimura
Makoto
M
Uchiyama
D000293:Adolescent; D001706:Biopsy; D001724:Birth Weight; D002648:Child; D005260:Female; D005865:Gestational Age; D005923:Glomerulosclerosis, Focal Segmental / Q000175:diagnosis*; D006801:Humans; D007150:Immunohistochemistry; D015994:Incidence; D007230:Infant, Low Birth Weight; D007231:Infant, Newborn; D007234:Infant, Premature; D007564:Japan; D007668:Kidney / Q000473:pathology; D007674:Kidney Diseases / Q000453:epidemiology; D008297:Male; D009402:Nephrosis, Lipoid / Q000175:diagnosis; D050199:Podocytes / Q000473:pathology*; D012189:Retrospective Studies; D012307:Risk Factors; D025721:WT1 Proteins / Q000378:metabolism
D025721:WT1 Proteins