Is nephrogenesis affected by preterm birth? Studies in a non-human primate model

Gubhaju, Lina, Sutherland, M, Yoder, B, Zulli, Anthony, Bertram, John and Black, M. Jane (2009) Is nephrogenesis affected by preterm birth? Studies in a non-human primate model. American Journal of Physiology : Renal Physiology, 297 (6). F1668-F1677.

Abstract

Nephrogenesis occurs predominantly in late gestation at a time when preterm infants are already delivered. The aims of this study were to assess the effect of preterm birth and the effect of antenatal glucocorticoid treatment on nephrogenesis. Preterm baboons, which were delivered at 125 days gestation and ventilated for up to 21 days postnatally, were compared with gestational controls. A cohort of preterm baboons that had been exposed to antenatal glucocorticoids were compared with unexposed preterm baboons. The number of glomerular generations was estimated using a medullary ray glomerular-counting method, and glomerular number was estimated using unbiased stereology. CD31 and WT-1 localization was examined using immunohistochemistry and VEGF was localized using in situ hybridization. The number of glomerular generations was not affected by preterm birth, and total glomerular numbers were within the normal range. Kidneys were significantly enlarged in preterm baboons with a significant decrease in glomerular density (number of glomeruli per gram of kidney) in the preterm kidney compared with gestational controls. Neonates exposed to antenatal steroids had an increased kidney-to-body weight ratio and also more developed glomeruli compared with unexposed controls. Abnormal glomeruli, with a cystic Bowman's space and shrunken glomerular tuft, were often present in the superficial renal cortex of both the steroid-exposed and unexposed preterm kidneys; steroid exposure had no significant effect on the proportion of abnormal glomeruli. The proportion of abnormal glomeruli in the preterm kidneys ranged from 0.2 to 18%. In conclusion, although nephrogenesis is ongoing in the extrauterine environment, our findings demonstrate that preterm birth, independent of steroid exposure, is associated with a high proportion of abnormal glomeruli in some, but not all neonatal kidneys. Whether final nephron endowment is affected in those kidneys exhibiting a high proportion of abnormal glomeruli is yet to be confirmed.

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Item type Article
URI https://vuir.vu.edu.au/id/eprint/4316
DOI 10.​1152/​ajprenal.​00163.​2009
Official URL http://ajprenal.physiology.org/content/297/6/F1668...
Subjects Historical > Faculty/School/Research Centre/Department > School of Biomedical and Health Sciences
Historical > FOR Classification > 0606 Physiology
Historical > FOR Classification > 1114 Paediatrics and Reproductive Medicine
Historical > FOR Classification > 1116 Medical Physiology
Historical > SEO Classification > 970111 Expanding Knowledge in the Medical and Health Sciences
Keywords ResPubID17742. nephrogenesis, kidney, preterm birth, infants, antenatal glucocorticoid treatment, glomerulogenesis, renal, baboons
Citations in Scopus 96 - View on Scopus
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