Chapters authored
Neuro-Insular Complexes in the Human Pancreas
It is well known that pancreatic islets are complex structures composed of endodermally derived endocrine cells, integrated with endothelial cells and other cells, originating from the mesoderm, and innervated by nerve fibers that have a neuroectodermal origin. In our studies, we focused on the interactions between the structures of the nervous system and endocrine cells, the so-called neuro-insular complexes, in the human pancreas. In this chapter, we present our results and literature data concerning the morphological organization of neuro-insular complexes in humans and other mammals. We also discuss the possible functional role of neuro-insular complexes, such as the involvement of the nervous system in the regulation and synchronization of islet hormone secretion and the morphogenetic plasticity of the endocrine pancreas in adults, as well as in the regulation of endocrine cell proliferation and maturation during prenatal development of the pancreas.
Part of the book: Challenges in Pancreatic Pathology
Development of Human Pancreatic Innervation
Human pancreatic innervation is of particular interest due to its possible role in the pathogenesis of such diseases as diabetes mellitus, pancreatitis and pancreatic cancer. Despite the clinical importance, data concerning pancreatic innervation during human ontogeny and in various disorders are very limited. In this chapter, we present a review on human pancreatic autonomic innervation on the basis of the literature data and our previous results. Special attention is paid to the innervation of the endocrine pancreas. Gradual branching of neural network was seen during human pancreatic development. Innervation of the foetal pancreas is more abundant than in adults. In agreement with previous observations, we have revealed a close integration and similarity between endocrine cells and nervous elements in the developing human pancreas. Moreover, simultaneous interactions between the nervous system components, epithelial cells and endocrine cells were detected in the pancreas during prenatal human development. It has been suggested that pancreatic innervation plays an important role not only in regulation of endocrine and exocrine activity but also in normal islet morphogenesis.
Part of the book: Autonomic Nervous System
Ontogeny of the Human Pancreas
Pancreatic disorders are the most common pathologies in humans worldwide. Detailed information on pancreatic cytoarchitecture, vascularisation, innervation, morphogenesis, and cell differentiation is required for the development of new approaches to the treatment of these diseases. Currently, the majority of studies on pancreas development are performed on experimental animals (mainly rodents). Studies on human pancreatic prenatal development are restricted in number by ethical constraints and some technical difficulties. However, interspecies differences in pancreatic structure and development are considerable. Therefore, data obtained in experiments on animals and cell cultures must be supplemented with information obtained directly from human pancreatic autopsies. In this chapter, we summarise our previous results and the literature data on human pancreatic ontogeny. Special attention has been paid to the endocrine pancreas, which undergoes morphogenetic restructuring during human development. Several forms of structural organisation of the endocrine pancreas (single endocrine cells, small clusters of endocrine cells, mantle, bipolar, and mosaic islets) gradually appear during development. It is important that this restructuring is accompanied by changes in the ratio of pancreatic endocrine cells. The mechanisms of these changes are still unclear. The difficulties in identifying progenitor cells and tracking cell differentiation are the main problems associated with this issue.
Part of the book: Comparative Endocrinology of Animals