Telocytes (Tcs) and pericytes (Pcs) are two types of perivascular interstitial cell known to be widespread in various organs and tissues, including the brain. We postulated that Tcs and Pcs may be involved in glioblastoma (GBM) neovascularization. Objective: Morphological study of Tc and Pc roles in GBM. Materials and Methods: Samples from 15 GBM, 10 diffuse astrocytoma, as well as 5 control samples were studied. We used immunohistochemistry (IHC) with antibodies (Abs) to GFAP, Ki-67, CD117, NeuroD1, NG2, CD34, and SMA. Confocal laser scanning microscopy (CLSM) of 4 glioma tissue cultures and 4 GBM sections was performed with GFAP, CD117, CD34/connexin43, NeuroD1/connexin43, CD34/NG2 and CD13/ CD117 Abs. Electron microscopy (EM) of GBM was performed in 4 cases. Results: The presence of Tcs and Pcs was shown in GBM (IHC, EM, CLSM) and glioma cultures (CLSM). 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 higher 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. These and forthcoming improvements in our understanding of the origin and function of Tcs, including their relationship with Pcs, are necessary steps in oncology. Study of these cell types (Tcs, Pcs) and their roles in brain tumor oncogenesis will likely enable improved targeted therapies and support development of new forms of anti-neoplastic drugs.

The prognosis of glioblastoma (GLB) is poor: the 5-year survival rate is less than 10%. Almost all patients relapse after surgery according to the standard of treatment: resection, radiation therapy, and temozolomide. T reatment options today for relapse are limited, and no amount of therapy prolongs patients' lives. The development of resistance to therapy is associated with the microenvironment and tumor stem cells. Objective: to study the expression of stem cell markers, transcription factors and PD-L1 in malignant gliomas. A retrospective study included 17 patients with high-grade gliomas who underwent surgery. All patients underwent traditional histological examination, immunohistochemical analysis with antibodies to IDH1R132H, BRAF V600E, Ki-67, GFAP, NANOG, Nestin, CD133, SALL4, OCT4, SOX2, CD38, PD-L1, FOXM1, morphometric analysis with calculation of the average ratio cells with antigen expression to the number of all tumor cells. Expression of NANOG was observed in 47% of cases, Nestin - in 88%, CD133 - in 71%, SOX2 - in 100%, CD38 and FOXM1 - in 65%. None of the tumors expressed SALL4, only one OCT4. PD-L1 expression was detected only in 2 cases. Correlation analysis established the presence of significant associations between the expression of Nestin and CD133; FOXM1 and NANOG; Nestin and CD38; Ki-67 and SOX2. The presence of expression of stem cell markers and transcription factors NANOG, Nestin, CD133, CD38, SOX2, FOXM1 in malignant gliomas, in our opinion, dictates further targeted study of these markers on a larger sample and opens up new potential targets for targeted therapy.

Endomyocardial biopsy (EMB) is the method of choice for diagnosing a wide range of myocardial diseases.Aim. To assess the rationale for diagnostic EMB in children and adults.Material and methods. Morphological and statistical analysis of 2803 diagnostic EMBs in adults (n=811) and children (n=83), including those in heart transplantation (n=1909), was carried out.Results. In 231 (28%) cases, adults were diagnosed with myocarditis, of which in 6 patients — granulomatous, in 5 — eosinophilic and in 6 — lymphocytic-macrophage myocarditis after coronavirus infection. In children, myocarditis was found in 22 cases (27%). Arrhythmogenic right ventricular dysplasia took the second place in detection rate in children and adults. Immunohistochemical study revealed viral envelope protein 1 (VP1) antigen of enteroviruses in one third of myocarditis cases, and in half — other cardiotropic viruses. Dotted dystrophin expression was observed in myocarditis. A correlation was established between the perforin expression and myocarditis presence (Pearson χ2=27,8; Fisher's exact test=27,3; p=0,01).Conclusion. Analysis of diagnostic EMB results confirmed its rationale in adults and children not only for heart transplantation, but also for identifying cardiac pathology, including for myocarditis diagnosis. It has been shown that immunohistochemical study with antiviral antibodies can be considered as an alternative method for detecting viral infection. An immunohistochemical analysis for perforin and dystrophin can be recommended as additional morphological markers of myocarditis.

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