Distribuição de componentes celulares, vasculares, e estromais na ilhota pancreática humana em amostras de fetos e crianças

Abstract

The pancreas is an extremely important organ, as it is involved in glucose homeostasis and facilitating digestion, performing fundamental endocrine and exocrine functions for the human body. Its exocrine function involves the production and secretion of digestive enzymes, and its endocrine function depends on the functioning of pancreatic islets, which regulate insulin and glucagon levels. Understanding the normal development and function of pancreatic islets in fetuses and prepubertal children is essential to identify abnormalities or disorders related to glucose metabolism. In this sense, we investigated the histological changes of cells, vascularization and stroma in the pancreatic islet of fetuses and pre-pubertal children. For this, we used pancreas samples from fetuses with a gestational age of 15 to 20 weeks and pancreas samples from children aged between 1 and 5 years. The antibodies used were anti-syndecan-4, anti-perlecan, anti-insulin, anti-glucagon, anti-SMA and anti-CD31. After immunohistochemistry markings, morphometric and statistical tests were performed. All samples showed practically unchanged cytoarchitecture. The distribution of collagen fibers inside and on the periphery of the islets was more evident in children. Beta cell density was also higher in children. In contrast, the amount of alpha cells was higher in fetuses. Regarding proteoglycans, syndecan-4 is present in relatively high amounts in fetuses, but perlecan did not show significant differences between the two age groups. We also observed that the anatomical regions of the pancreas (head, body and tail) differed statistically only in fetuses through staining with anti-CD31, which reflects vasculature still in formation. Therefore, in the fetal pancreatic environment we observe a more intense angiogenic activity, necessary to provide nutrients and oxygen to growing cells. On the other hand, in prepubertal children there is greater collagen production and organization as well as the higher beta cell density suggests the need for a more effective support structure for the pancreatic islets in order to facilitate secretion and regulation of insulin.