Histomorphometric Analysis of Postnatal Glomerul

Authors: Maria M Rodríguez Alexander H Gómez Carolyn L Abitbol Jayanthi J Chandar Shahnaz Duara Gastón E Zilleruelo

Publish Date: 2004/03/04

Volume: 7, Issue: 1, Pages: 17-25

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Abstract

Until now oligonephropathy to indicate “too few nephrons” has been associated with intrauterine growth restriction and experimentally induced abnormalities of renal development The purpose of this study was to determine whether there is evidence of abnormal postnatal glomerulogenesis in extremely low birth weight preterm infants Renal autopsy tissue was studied by computerassisted morphometry from 56 extremely premature infants birth weight ≤ 1000 g and 10 fullterm infants as controls Preterm infants were divided into two groups short survival 40 days vs long survival ≥40 days Each group was subdivided into those with renal failure RF and those with normal renal function Fortytwo of 56 preterm infants 75 were adequate for gestational age Glomerulogenesis as measured by radial glomerular counts RGC was markedly decreased in all preterm infants as compared to term controls and correlated significantly with gestational age r = 087 P 0001 Active glomerulogenesis with “basophilic Sshaped bodies” was absent in longer surviving preterm and all term infants RGC of preterm infants surviving ≥40 days with RF were significantly less than RGC of those with long survival and no RF P 0001 Only this latter group demonstrated increased glomerular size as measured by mesangial tuft area and Bowman’s capsule area compared to all other groups P 0001 The kidney continues to form postnatally in preterm neonates but glomerulogenesis ceases after 40 days Moreover it is further inhibited by RF Compensatory mechanisms in longer surviving preterm infants include glomerular hypertrophy and mesangial proliferation that could lead to hyperfiltrationWe thank Dr Liliane J Striker and Anna R Plati from the Laboratory of Renal Cell Biology Division of Nephrology Department of Medicine University of Miami for allowing us to use the morphometric analysis system We also thank Carmen Duboue HT ASCP and Bonnie Cohen HT ASCP for their assistance cutting histologic renal preparations and performing PAS stains

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