Histogenesis of Human Fetal Kidney: A Cross-Sectional Descriptive Study in a Tertiary Care Institution in the Northeastern Region

Introduction: The evaluation of fetal kidney has been subject of increased awareness for the assessment of fetal growth and development and prenatal diagnosis of renal anomalies, genetic counselling and treatment of prenatal renal disorders like Wilm’s tumor, multicystic renal dysplasia, hydronephrosis. Objective: The aim of the study was to determine the histological development of the kidneys during the fetal period. Materials and Methods: The present study was carried out in the department of Anatomy, Regional Institute of Medical Sciences, Imphal, Manipur. The material for the study consisted of 60 spontaneously aborted and still born human fetal specimens free from any gross congenital anomalies with gestational age between 11th to 38th weeks were collected from Obstetrics and Gynaecology Department, RIMS. The kidneys were taken out from fetal specimens, fixed, processed to form slides and studied under the light microscope for histological changes of kidney with advancing age after staining with Haematoxylin and Eosin. Results: The capsule of kidney was made up of collagen fibres and fibroblasts at 11 weeks of gestation, which were differentiated with numerous collagen fibrils at 16 weeks and from 20 weeks onwards thick compact capsule is formed. Nephrogenic zone beneath the capsule was seen as a broad at 11 weeks of gestation which is decreased and it was almost negligible at 38 weeks of gestation. Developing glomeruli were observed in the superficial part of the cortex initially while with advancing gestational ages from 11 weeks to 38 weeks they were located in the deeper part of cortex. The cortico-medullary differentiation was appreciated from 14 weeks onwards and completed by 27 weeks, PCT and DCT were identified at 16th week of gestation. The medulla showed connective tissue and few clusters of cells at 11 weeks of gestation which were differentiated to a few collecting tubules at 14 weeks and thick and thin segments of Henle’s loop were seen by 18 weeks. Conclusion: The present work made an initial attempt to analyze the growth pattern of kidney in human fetuses, which may prove useful in defining the fetal kidney diseases such as agenesis, hypoplasia, polycystic kidney etc., more precisely using the modern invasive or non-invasive imaging technique.