Abstract.
The incidence of cardiovascular disease in Italy and in economically developed countries is very high, with a high rate of mortality and morbidity among those affected. Myocardial infarction, one of the most common diseases, in the 10% of cases is associated with viral acute myocarditis and its long-term sequela, or dilated cardiomyopathy (CMD). Viral etiology is evidenced by the presence of viral genomes and proteins in the pericardial fluids of patients affected by myocarditis. The most cardiotropic viruses such as Adenovirus type 2 and 5, and Enterovirus, especially strains of
Coxsackievirus B1-B6, exploit for their internalization the surface glycoproteins of cells
(Coxsackie and Adenovirus “Receptor" and "Decay-Accelerating Factor ", separately or in the form of DAF-CAR complex receptor). The innovations in the medical treatments and in the operation field have significantly reduced mortality due to heart attacks, but currently there are not resolutive methods that allow to repair the permanent damage caused directly by the disease. A new resolutive remedy could be represented by the implant of stem cells to replace damaged cardiomyocytes. Our purpose is the analysis of susceptibility of cardiac resident murine (C-TERT) and human (HHTO2)
stem cells in the first stage of differentiation, engineered with the catalytic subunit of telomerase to
be infected by Coxsackie vaccine strain virus B1-B6 and the clinically isolated strain B3. After the verification of the internalization of the virus, by the expression of the receptor CAR, as RNA (RT-PCR) and as protein (enzyme immunoessay), that is a necessary and sufficient condition, the cells were infected by a mixture of coxsackie B1-B6 (reference vaccine strains), by the 6 strains separately and by the isolated B3 at a concentration of 300 PFU and 3 serial dilutions base 10, as a positive control cell line KB (human epidermoid carcinoma) has been used. After 48, 72 and 96 hours after infection the viral genome was sought in the supernatant and cells separately by
RT-PCR and the expression of viral antigens by indirect IFA has been evaluated. The stem cell lines
have shown no sign of cytopathic effect at all time points after infection and at all dilutions. On the contrary, the KB cell line that showed signs of cell death from 48 hours. The viral genome was detected in the TERT C-line, KB cells, but not in the stem line HHTO2, only in the supernatant of the control line KB at all time points after infection and at all dilutions. The stem cell line C-TERT seems to internalize the Coxsackie B virus, but it does not allow the production of mature virions, while the stem line HHTO2 seems not even to allow internalization in spite of the identical expression of receptor proteins. In order to understand if it is possible to select the resistant clones and to use them for the infusion when necessary, it should be investigated the evolution of susceptibility to infection with more cardiotropic viruses at following stages of differentiation.
