ИСТИНА

Background & objectives: Telocytes (Tcs) and pericytes (Pcs) are two types of perivascular interstitial cell known to be widespread in various organs and tissues, including the brain. Objective: morphological study of Tc and Pc role in glioblastoma (GBM) neovascularization. Methods: Samples from 15 GBM, 10 diffuse astrocytomas and 5 tumour-free frontal lobes (control samples) were studied. We used immunohistochemistry and double immunohistochemical staining with antibodies to GFAP, Ki-67, CD117, NeuroD1, NG2, CD34, SMA, connexin43; confocal laser scanning microscopy of glioma cultures and frozen and paraffin embedded GBM sections. Electron microscopy of GBM was performed in 4 cases. Results: The presence of Tcs and Pcs was shown in GBM sections and glioma cultures. The Tc immunophenotype was CD117+/CD34+/connexin43+/NeuroD1+. The Pc immunophenotype was SMA+/NG2+/CD13+. The number of Tcs in GBM specimens was 10 times more than in astrocytoma. We also identified CD13/CD117 and CD34/NG2 co-expressing cells in GBM blood vessels. Conclusion: Four immunophenotypes were found in GBM vessels, corresponding to endotheliocytes, Pcs, Tcs, and a mixed Pc/Tc immunophenotype. Study of these cell types and their roles in brain tumour oncogenesis will likely enable improved targeted therapies.