Prenatal development of the human endocrine pancreas: A morphological and immunohistochemical study

Abstract Introduction The endocrine pancreas plays a pivotal role in glucose metabolism. As regards the morphogenesis of the islets of Langerhans, there is conflicting data regarding the timing of appearance of the B cells, and, the proportion and arrangement of the B cells within the islets. The present work is a baseline study conducted in the Indian subcontinent. The histogenesis of the islets of Langerhans was studied and we also observed the expression of anti-insulin antibody in the islets at different gestational ages. Methods Ten aborted fetal specimens of pancreas of gestational ages 10–36 weeks were procured from the Department of Obstetrics and Gynaecology, LNJP Hospital, New Delhi. Fetuses were fixed in 10% formalin. Serial sections were stained with Haematoxylin and Eosin and few sections were processed for immunocytochemistry with a specific marker for B-cell, the anti-insulin antibody. Results The cells of the islets arise from the lining epithelium of the tubules. The B cells contain insulin at 10th week as seen by immunostaining. Small capillaries are seen enclosed in the islets at 14 weeks. The arrangement of B cells in different islets is variable. The formation of islets continues throughout fetal life. Discussion Our study reaffirms that the endocrine pancreas begins to differentiate early in fetal life. The growth and maturation of islets is associated with coordinated vascular development. By the 28th week of intrauterine life, the fetal pancreas attains sufficient morphological maturity so as to fulfil the hormonal requirements of the growing fetus.