Telocytes: history, origin, identification, structure, distribution, and functions

Telocytes are specialized interstitial cells characterized by their unique structure, which features a relatively small cell body and long cytoplasmic projections, called telopodes. Formerly referred to as interstitial Cajal-like cells, telocytes are capable of forming a complex communication network between various stromal and epithelial cell types. Despite their positive staining for CD34 and vimentin antibodies, the mesenchymal origin of these cells, as well as whether telocytes should be considered distinct cell populations or just a subpopulation of other stromal cells, remains uncertain. Telocytes have been shown to perform various functions, ranging from establishing complex three-dimensional networks, serving as an important component of stem cell niches and playing a huge role in the formation of tissue barriers, to serving as one of the key regulators of cell differentiation, having immune functions, and taking part in angiogenesis and even in organ morphogenesis. The functional diversity exhibited by telocytes in different tissues makes their study more complicated, and the exact molecular mechanisms underlying their function remain inadequately understood. As a new and intriguing field of research, telocytes hold considerable promise for improving our understanding of connective tissue physiology.