Quantitative study of the comma-shaped body, S-shaped body and vascularized glomerulus in the second and third human gestational trimesters.
BACKGROUND
The rat developing metanephros has been quantified, but not the human developing kidney.


OBJECTIVE
To contribute to the knowledge of the human developing kidney by studying the relative growth of the glomerular structures subtypes in the last two gestational trimesters.


METHODS
The glomerular compartment of 21 human fetal left kidneys was studied. A stereological study determined the volume density (V(V)), the surface density (S(V)), and the numerical density in the plane (N(A)) of the developing glomeruli in the stages of comma-shaped body (C), S-shaped body (S), and vascularized glomerulus. Growth curves used log-transformed data and the allometric model.


RESULTS
Reduction of both C and S bodies, and, consequently, a relative growth of the vascularized glomerulus from the second to the third trimesters. The differences between ages were not significant to the S body V(V) and S(V), but there was a significant N(A) reduction from the second to the third trimesters. An age-related reduction of the C body and an intense growth of the vascularized glomerulus were observed in this period. The allometric coefficient b was negative in both C and S bodies and positive in the vascularized glomerulus in the last two gestational trimesters.


CONCLUSIONS
The growth equations and the observed tendencies of these glomerular subtypes in human fetal life could be useful to assess the kidney maturity through invasive or noninvasive investigative methods in the future.
D005314:Embryonic and Fetal Development; D005260:Female; D005865:Gestational Age; D006801:Humans; D007678:Kidney Glomerulus / Q000098:blood supply / Q000196:embryology*; D008297:Male; D009024:Morphogenesis; D038081:Organogenesis / Q000502:physiology*; D011247:Pregnancy; D011262:Pregnancy Trimester, Second; D011263:Pregnancy Trimester, Third