Distribution of S100-Positive Cells in Islets of Langerhans of the Fetal and Adult Human Pancreas

Abstract

The aim of the investigation was to study the distribution of S100-positive cells in the islets of Langerhans of human pancreas during prenatal and early postnatal development, as well as in adult humans.Materials and Methods. using antibodies to S100 protein, to main hormones produced in the islets of Langerhans in human pancreas (insulin, glucagon and somatostatin), and to neuron-specific enolase (NSE) we carried out an immunohistochemical analysis of human pancreatic samples. The samples were taken from adults without pancreatic diseases, from patients with type 2 diabetes mellitus, as well as from fetuses and newborns.Results. Two types of S100-positive cells can be found in human islets of Langerhans starting from gestation week 15-16: cells located on islet periphery, and cells situated inside an islet. Cells located on periphery are flattened and have small amount of cytoplasm. These cells have long processes extending mainly along periphery. The cells located inside islets are oval-or round-shaped, and generally have no processes.Conclusion. In an early fetal period in islets of Langerhans of human pancreas, two types of S100-positive cells appear, they being different in their structure. The cells on periphery are similar morphologically to glial cells. The cells inside islets are no different in their structure from other endocrine cells. Two types of S100-positive cells can be suggested to be of importance both in islet morphology, and in the regulation of hormones expressed by endocrine cells.

Neuro-Insular Complexes in the Human Pancreas

“…We found small S100-positive cells with thin processes at the periphery of some islets in humans [37,38]. The same small oval, triangular or elongated cells with long thin processes were observed in the fetal pancreas using electron microscopy [38].…”

Localisation of S100 Protein and Acetylated Tubulin in Sheep Pancreas

“…The two cell types in the islets of Langerhans are distinguished in the early foetal period of the human pancreas, with two types of S100 positive cells appearing that differ in structure. Peripheral cells are morphologically similar to glial cells [25]. The cells inside the islets do not differ in structure from other endocrine cells.…”

“…There were no such differences in sheep pancreas, but different intensity of antibody staining was observed between positive cells. P r o s h c h i n a et al [25] found in humans small S100-reactive cells with thin processes on the periphery of some islets. The processes of these cells often cover or surround the nerve fibres passing to the islets [20,25].…”

“…Two types of S100 positive cells can be found in the human islets of Langerhans cells located on the periphery of the islets and cells located inside the islet. Cells located at the periphery have long processes running mainly along the periphery, while cells located inside the islets generally have no processes [25]. Interactions between thin nerve fibres and endocrine cells located separately or within islets predominated [25].…”

“…The S100 protein was localized in various exocrine and endocrine organs, where immunoreactivity to the S100 protein was limited to some secretory cells and to ductal cells. In human and animal pancreases, the S100 protein has been used to identify nerve structures and to identify cell types in the pancreatic islets [1,25,32]. S u n a m i et al [30] demonstrated the three-dimensional architecture of peri-island nerve plexuses in the mouse pancreas by staining for the S100 protein.…”