Subsets of telocytes: Myocardial telocytes

Area of Science:

• Cardiovascular Biology
• Cell Biology
• Histology

Background:

• Telocytes (TCs) are characterized by long telopodes (Tps) and are often considered a distinct cell type in various tissues.
• Transmission electron microscopy (TEM) has been the standard for identifying myocardial TCs.
• Previous studies suggest TCs play significant roles in cardiac tissue.

Purpose of the Study:

• To investigate the validity of previous studies on myocardial telocytes.
• To determine if myocardial telocytes represent a unique cell population or are part of other lineages.
• To re-evaluate the identification criteria for myocardial telocytes.

Main Methods:

• Immunohistochemistry was performed on human cardiac samples using antibodies for CD10, CD31, CD34, CD146, Ki67, α-SMA, PDGFRα, and laminin.
• Transmission electron microscopy (TEM) was conducted on human and rat cardiac samples.
• Cellular markers and ultrastructural morphology were analyzed to identify cell types.

Main Results:

• Endothelial cells (ECs), cords, and tip cells expressed markers like CD10, CD31, CD34, CD146, and PDGFRα.
• Endothelial progenitor cells and nascent capillaries were identified by CD31+/CD34+ expression.
• TEM revealed endothelial tubes in myocardial interstitia, with ECs appearing identical to previously described myocardial TCs, suggesting a subset of TCs belong to the endothelial lineage.

Conclusions:

• The morphological characteristics and markers of some cells identified as myocardial telocytes align with those of endothelial cells.
• A subset of cells with TC-like phenotypes and telopodes-like processes appear to be involved in blood vessel formation.
• Current data suggests that previous studies may not provide sufficient evidence for the reproducibility of myocardial telocyte identification, with some TCs potentially being endothelial in origin.