Human cardiac telocytes: 3D imaging by FIB‐SEM tomography

Abstract

Telocyte (TC) is a newly identified type of cell in the cardiac interstitium (www.telocytes.com). TCs are described by classical transmission electron microscopy as cells with very thin and long telopodes (Tps; cellular prolongations) having podoms (dilations) and podomers (very thin segments). TCs’ three-dimensional (3D) morphology is still unknown. Cardiac TCs seem to be particularly involved in long and short distance intercellular signalling and, therefore, their 3D architecture is important for understanding their spatial connections. Using focused ion beam scanning electron microscopy (FIB-SEM) we show, for the first time, the whole ultrastructural anatomy of cardiac TCs. 3D reconstruction of cardiac TCs by FIB-SEM tomography confirms that they have long, narrow but flattened (ribbon-like) telopodes, with humps generated by the podoms. FIB-SEM tomography also confirms the network made by TCs in the cardiac interstitium through adherens junctions. This study provides the first FIB-SEM tomography of a human cell type.

Telocytes in minor salivary glands of primary Sjögren's syndrome: association with the extent of inflammation and ectopic lymphoid neogenesis

“…Stromal cells include fibroblasts, dendritic cells, vascular endothelial cells and pericytes, but an additional type of stromal cells with peculiar phenotypical features has been recently identified and characterized in human and animal tissues . These cells, named telocytes (telos, i.e .…”

“…These cells, named telocytes (telos, i.e . provided with long‐distance cell projections), display a small cell body and extremely long cytoplasmic processes (telopodes) with a moniliform aspect characterized by the combination of thin segments (podomers) and dilated regions (podoms) . The peculiar ultrastructural phenotype is currently considered as the most reliable hallmark for these cells, which do not possess unique immunophenotypic characteristics .…”

Myocardial Telocyte-Like Cells: A Review Including New Evidence

“…Yet, other studies did not use specific markers for the identification of TCs, a process that was instead performed exclusively using transmission electron microscopy (TEM) [Gherghiceanu and Popescu, 2012;Cretoiu et al, 2014;Fertig et al, 2014]. For instance, a study of cardiac TCs in cell cultures used only TEM to characterize them [Popescu et al, 2016].…”

Exercise Training Protects Against Acute Myocardial Infarction via Improving Myocardial Energy Metabolism and Mitochondrial Biogenesis

“…In the present study, we found that the enhanced mitochondrial biogenesis in the acute phase of AMI was accompanied with an early adaptive response of mitochondrial biogenesis in the acute phase of AMI which might It has to be mentioned that the protective effect of exercise against the acute myocardial injury following AMI should be more complex than involving myocardial energy metabolism and mitochondrial biogenesis. It has recently been reported that telocytes, a novel interstitial cell type, with extremely long and thin processes, play important roles in tissue repair and regeneration [54][55][56][57][58]. Telocytes have been found to be decreased in myocardium reduce myocardial infarction [59][60][61].…”