Telocytes inside of the peripheral nervous system - a 3D endoneurial network and putative role in cell communication.

In this paper, we developed the hypothesis concerning the reasons to assimilate endoneurial fibroblast-like dendritic phenotype [shortly termed endoneurial dendritic cells (EDCs)] to the endoneurial telocytes (TCs). We reviewed the literature concerning EDCs status and report our observations on ultrastructure and some immune electron microscopic aspects of the cutaneous peripheral nerves. Our data demonstrate that EDCs long time considered as fibroblasts or fibroblast-like, with an ovoidal nucleus and one or more moniliform cell extensions [telopodes (Tps)], which perform homocellular junctions, also able to shed extracellular microvesicles can be assimilated to TC phenotype. Sometimes, small profiles of basement membrane accompany to some extent Tps. Altogether data resulted from scientific literature and our results strength the conclusion EDCs are really TCs inside of the peripheral nervous system. The inner three-dimensional (3D) network of endoneurial TCs by their homo- and heterocellular communications appears as a genuine cell-to-cell communication system inside of each peripheral nerve.

Relevant infrastructural alterations in invasive pancreatic ductal adenocarcinoma.

In this study, we focus our interest on some peculiar infrastructural abnormalities detected in a pancreatic cancer case. Our electron microscopic observations underline the high plasticity of the pancreatic parenchyma cells. Tumor pancreatic exocrine lesions are represented by putative ductal and acinar cells, which proliferate and grow in a haphazard pattern, detrimental to endocrine counterpart. The tumor cells do not exhibit neither a pure ductular or ductal nor a pure acinar phenotype, but tumor lesions represented by neoplastic ductal cells with invasive growth are by far prevalently. In our pancreatic cancer case, electron microscopic investigation clearly shows that a plethora of the epithelial cells from the tumor lesions contain large areas of autophagy leading to the pleomorphic inclusions represented by fibrillary÷filamentous inclusions frequently associated with hyaline-amorphous material, and secondary lysosomes. One of the mostly striking and important finding in this report for a case of pancreatic cancer is the high fragility (extensive dissolutions) of plasma membrane of tumor cells leading to pseudo-syncytia formation. Desmosomal junctions are severely altered, almost missing. Plasma membranes showed shedding membrane vesicles. Extravasated inflammatory cells contribute to the dramatic and extensive destructive areas of epithelial cells as well as tumor-stroma counterpart, including the basement membrane. All above severe infrastructural abnormalities, especially down regulation of cell-cell and cell-extracellular matrix adhesions might result in aberrant cell behavior and, consequently, much care should be taken for the postoperatory patient evolution.

Relevant infrastructural alterations in a pancreatic neuroendocrine tumor: an insulinoma case.

In this study, we focus our interest on some peculiar infrastructural abnormalities detected in an insulinoma case. Tumor pancreatic endocrine cells proliferated detrimental to exocrine counterpart, so that extensive areas of prevalent ß-tumor cells can be seen. Two phenotypes of ß-tumor cells can be identified: (1) ß-tumor cells with full euchromatic and nucleolated nuclei and (2) ß-tumor cells with heterochromatic and shrink nuclei. Because of stroma alteration, including basement membrane, cell-extracellular matrix junctions are also compromised. The mostly striking and important finding in this report for a case of insulinoma is the high fragility of plasma membrane of both two phenotypes of ß-tumor cells. Cell-cell junctions, especially desmosomal junctions are severely altered, almost missing, plasma membranes showed shedding membrane vesicles and extensive dissolutions leading to pseudo-syncytia formation. Extravasated blood cells, including inflammatory cells contribute to the dramatic and extensive destructive areas of epithelial cells as well as stroma counterpart. Moreover, also the inner cell cytomembranes exhibit abnormalities: many ß-tumor cells have excessive dilatations of nuclear envelope and endoplasmic reticulum. All above severe infrastructural abnormalities, especially down regulation of cell-cell and cell-extracellular matrix adhesions and plasma membranes fragility might result in aberrant cell behavior and, consequently, much care should be taken for the postoperatory patient evolution.