From TELOCYTES to TELOCYTOPATHIES. Do Recently Described Interstitial Cells Play a Role in Female Idiopathic Infertility?

Identification of telocytes in the oviduct of the mare

Telocytes (TCs), a recently discovered special type of stromal cells, have been identified in many organs of many species, including the female and male reproductive system, with proposed multiple potential bio-functions such as homeostasis, immunomodulation, tissue remodeling and regeneration, embryogenesis, angiogenesis and even tumorigenesis. The aim of this study was to investigate the existence, and characteristics of telocytes in normal equine oviduct. To identify them, we used routine light microscopy, non-conventional light microscopy (NCLM), transmission electron microscopy (TEM), and immunohistochemistry. We found that telocytes of the equine oviduct can be recognized in fixed specimens by light microscopy (methylene blue staining), with more details on Epon semi-thin sections (toluidine blue staining) by NCLM, and that they showed positive immunostaining for CD34. The telocytes, with their typical long and moniliform prolongations, formed networks in the stromal space of the submucosa, muscular and serosa layers, particularly in the lamina propia where they were observed in greater quantity. By TEM we have also confirmed the presence of cells ultrastructurally identifiable as telocytes (cells with telopodes alternating podomers and podoms) in the aforementioned locations. Direct intercellular contacts between epithelial cells and neighboring telocytes were evidenced. EIn conclusion, we demonstrated that telocytes are present in the equine oviduct as previously reported in other species. The potential implication of telocytes in multiple potential functions of physiological and pathological processes deserves further investigation.

Telocytes in Cutaneous Biology: A Reappraisal

The telocytes (TCs) are novel interstitial cells that have been overlooked for a long time due to their histologic similarity to other stromal cells. TCs can be separated from the stromal cells based on their distinct immunohistochemical, ultrastructural, and molecular features. Functionally, TCs are involved in the tissue renewal, mechanical support, and immune modulation. These cells are also involved in the signal transduction either through their direct interactions with the neighboring cells or through the paracrine signaling via extracellular vesicles. TCs are damaged in several inflammatory and fibrotic conditions such as ulcerative colitis, Crohn's disease, hepatic fibrosis, psoriasis, and systemic sclerosis. The transplantation of TCs in the damaged tissue can promote tissue regeneration. Therefore, enhancing tissue TCs either by their transplantation or by promoting their survival and growth using novel medications represents novel therapeutic strategy in the future. In this review, we addressed several aspects of TCs including their origin, distribution, morphologic features, and functions. We also discussed their involvement of the cutaneous TCs in the development various pathologic conditions.

Telocytes and endometriosis

Endometriosis involving the presence and growth of glands and stroma outside the uterine cavity is a common, inflammatory, benign gynecologic disease. Nevertheless, no single theory can exactly account for the pathogenesis of endometriosis. Telocytes, a kind of novel mesenchymal cells, have been suggested to be crucial in promoting angiogenesis and increasing the activity of endometrial interstitial cells and inflammatory cells. Given above roles, telocytes may be considered as the possible pathogenesis of endometriosis. We reviewed the current literature on telocytes. The following aspects were considered: (A) the telocytes' typical characteristics, function, and morphological changes in endometriosis; (B) the potential role of telocytes in endometriosis by impacting the inflammation, invasion, and angiogenesis; (C) telocytes as the potential treatment options for endometriosis.

Matrix metalloproteinase gene mutations and bioinformatics of telocytes in hepatocellular carcinoma

Telocytes (TCs) have crucial functions to promote the metastasis of hepatocellular carcinoma (HCC) by over-expressing matrix metalloproteinases (MMPs), but the mechanism by which TCs secrete MMPs in the genome is still unknown. We first cultured and isolated primary TCs from distinct liver cancer tissues and hepatic hemangioma surrounding tissues (Control group). Their whole exon genes were tested by Illumina HiSeq family of platforms and by high-throughput sequencing as well as variant mutations. Moreover, immunohistochemistry, Western blot, and quantitative reverse transcription-polymerase chain reaction assays were utilized to assess the expression of MMPs. The perniciousness of signal-nucleotide polymorphism (SNP) mutations of proteins were predicted by the Polyphen-2 database. Divergent expression and overall survival (OS) of MMPs was screened by StarBase-Pan Cancer plate; and MMPs associated signaling pathways were found by Kyoto Encyclopedia Genes and Genomes. The "competing endogenous RNA (ceRNA)" network was constructed by Cytoscape software. We found that 12 specific types of SNP mutations related to 5 types of MMPs occurred in TCs of liver malignant tumors as a potential result of MMP1, MMP9, and MMP17 overexpression. High levels of MMP1, MMP7, and MMP9 represented poor OS in HCC, and an interactive network of MMPs is shown. Allele shifts of C/T (rs20544) and G/C (rs2250889) in MMP9 were risk factors for TCs in HCC by the prediction of the Polyphen-2 Database. (MMP9 (-3 C/T)) mutation might be a genetic mechanism of upregulating MMP9 in TCs.

Functional Morphology of the Human Uterine Tubes in the 21st Century: Anatomical Novelties and Their Possible Clinical Applications

The uterine tube (UT) pathologies account for 25-35 % of female factor infertility. Although these peculiar organs were first studied several hundred years ago, they have become overlooked and neglected mainly due to the successes of reproductive medicine. Nevertheless, reproductive medicine still faces many challenges regarding the fertility outcomes of in vitro fertilization (IVF). Many obstacles and problems can be resolved by a more detailed understanding of the UT morphology and function during normal reproduction. Over the course of the 21st century, many new insights have been obtained: the presence of a population of telocytes in the tubal wall responsible for normal motility and hormone sensory function, the demonstration of lymphatic lacunae of the mucosal folds necessary for oocyte capture and tubal fluid recirculation, or a thorough profiling of the immune makeup of the UT epithelial lining with the discovery of regulatory T cells presumably important for maternal tolerance towards the semi-allogenic embryo. New discoveries also include the notion that the UT epithelium is male sex hormone-sensitive, and that the UT is not sterile, but harbors a complex microbiome. The UT epithelial cells were also shown to be the cells-of-origin of high-grade serous ovarian carcinomas. Finally, yet importantly, several modern morphological directions have been emerging recently, including cell culture, the development of tubal organoids, in silico modelling, tissue engineering and regenerative medicine. All these novel insights and new approaches can contribute to better clinical practice and successful pregnancy outcomes.

Functional Morphology of the Human Uterine Tubes in the 21st Century: Anatomical Novelties and Their Possible Clinical Applications

The uterine tube (UT) pathologies account for 25-35% of female factor infertility. Although these peculiar organs were first studied several hundred years ago, they have become overlooked and neglected mainly due to the successes of reproductive medicine. Nevertheless, the reproductive medicine still faces many challenges regarding the fertility outcomes of in vitro fertilization (IVF). Many obstacles and problems can be resolved by a more detailed understanding of the UT morphology and function during normal reproduction. Over the course of the 21st century, many new insights have been obtained: the presence of a population of telocytes in the tubal wall responsible for normal motility and hormone sensory function, the demonstration of lymphatic lacunae of the mucosal folds necessary for oocyte capture and tubal fluid recirculation, or a thorough profiling of the immune makeup of the UT epithelial lining with the discovery of regulatory T cells presumably important for maternal tolerance towards the semi-allogenic embryo. New discoveries also include the notion that the UT epithelium is male sex hormone-sensitive, and that the UT is not sterile, but harbors a complex microbiome. The UT epithelial cells were also shown to be the cells-of-origin of high-grade serous ovarian carcinomas. Finally, yet importantly, several modern morphological directions have been emerging recently, including cell culture, development of tubal organoids, in silico modelling, tissue engineering and regenerative medicine. All these novel insights and new approaches can contribute to better clinical practice and successful pregnancy outcomes.