Safety of a Medicinal Product Based on Human Glial Progenitor Cells: A Pilot Study of Retrobulbar Administration in C57BL/6J Mice

INTRODUCTION. Stem cell therapy is a promising treatment method for various diseases and injuries, but its safety has yet to be determined. Therefore, studying the safety of administering a xenogeneic cell-based medicinal product (CBMP) into the retro-orbital venous sinus is essential for developing protocols for further studies of potential medicinal products for neurological conditions. AIM. The aim of the study was to determine the optimal dose of a CBMP derived from glial progenitor cells (GPCs) and to evaluate its safety during retrobulbar administration in C57BL/6J mice. MATERIALS AND METHODS. GPCs were derived from human induced pluripotent stem cells by stepwise differentiation and cultured in DMEM/F12 supplemented with epidermal growth factor and ciliary neurotrophic factor. Matrigel was used as a substrate. GPCs were injected into the retro-orbital venous sinus of male C57BL/6J mice under isoflurane anaesthesia once a week for two months. The study analysed changes in biochemical blood parameters and behaviour. The quantities of activated astrocytes and glial cells were determined by postmortem immunohistochemical staining. RESULTS. The administration of GPCs at a dose of 500×10 3 cells/mouse, which was selected using literature data, induced an increase in the plasma levels of ala nine aminotransferase and aspartate aminotransferase. This could indicate cell damage and the development of inflammatory reactions. At doses reduced to one-third the initial GPC concentration or lower, the biochemical blood parameters of the treatment groups did not differ significantly from those of the control group. There were no significant differences in neuroinflammatory markers between the groups receiving GPCs at different doses, except for an increase in astrocyte activation at a dose of 150×10 3 cells/mouse, which could potentially indicate inflammatory processes in the brain. The study detected no pathological changes in the brain or cell damage markers in the blood of mice after retrobulbar GPC injections of 15×10 3 or 50×10 3 cells/mouse. CONCLUSIONS. The study results indicate that long-term therapy with GPCs is potentially safe for mice if the dose is optimal. The authors suggest using the optimal doses and the administration route established in this study for further research into the safety of intravenous administration of CBMPs for neurological conditions.