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Hellenic Archives of Pathology, Volume 20, Issues 1-3, 2006
Émmunohistochemical study
of the intraparenchymal innervation
of human fetal kidney
Anagnostou V.1, Tiniakos D.1, Karandrea D.1,
Agapitos E.2, Kittas C.1
1Laboratories of Histology-Embryology and
2Pathology, Medical School, National and Kapodistrian University of Athens, Greece
The purpose of this study was to define, the development of intraparenchymal innervation and to assess the distribution and nature of intrinsic nerves in human fetal kidney. Our material consisted of routinely-processed renal tissue sections from 17 human fetuses (20-24 gestational weeks-gw, n=6; 25-40 gw, n=11) and 3 adults. We used immunohistochemistry with antibodies to the pan-neural markers neurofilaments (NF), neuron specific enolase (NSE), PGP9.5 and S100 protein. NF-, NSE-, S100- and PGP9.5-positive nerves were identified in the renal cortex, showing a perivascular (arterial and venous) distribution, from 20gw onwards. Their density appeared to increase with gestation, reaching adult levels at 28gw. Nerve fibers extended from the cortico-medullary region to the outer cortex, reaching the renal capsule in the 3rd trimester. In detail, NF, NSE-, S100- and PGP9.5-immunoreactive fibers were observed in close apposition to renal artery and its branches, occasionally reaching the afferent and efferent arteriole (3rd trimester). Nerve fibers were detected in close apposition to the juxtaglomerular apparatus in the 2nd and 3rd trimester. In the renal medulla, NSE-, PGP9.5- and S100-positive nerve fibers were detected close to tubular cells as early as 20 gw. However, their density gradually decreased during the 3rd trimester and were not observed in the medulla of the adult kidney. In conclusion, human fetal kidney appears richly innervated during the 2nd and 3rd trimester. There is progressive increase in the density of parenchymal nerve fibers towards term from the cortico-medullary region to the cortex. Most intrarenal nerves have a predominant perivascular distribution, implying that renal innervation plays an important functional role during intrauterine life.
Key words: Immunohistochemistry, innervation, fetal kidney.
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