ИСТИНА

Application of gene delivery techniques for modification of cells used in therapeutic methods is a new field that allows to enhance their paracrine and regenerative potential for increased efficacy and better safety. Mostly, these methods utilize the crucial role of paracrine stimuli generated by stem cells during tissue repair or regeneration. Over last years we have been elaborating to develop strategies using viral vectors to increase production of growth factors and “tune-up” the cells pro-regenerative capacity. Using adeno-associated viruses (AAV) and baculovirus we managed express growth factors in mesenchymal (MSC) and cardiac stem cells (CSC). Developed methods of viral delivery to express VEGF165 allowed to increase pro-angiogenic potential of cells and induce effective angiogenesis in ischemic tissue of experimental animals rendering effect that was significantly higher compared to GFP-treated or un-modified cells. Indeed, using nude mice to evaluate human MSC impact on recovery of blood flow, we found that VEGF-expressing MSCs had better survival and resulted in higher perfusion and blood vessel counts at experiment’s endpoint. Another approach we widely use is generation of cell sheets – minimal tissue-engineered constructs that consist of viable cells and extracellular matrix proteins forming a solid multilayered structure. Their expressed therapeutic potential relies on better survival after delivery compared to injection of dispersed cells. However, viral modification of constructs resulted in even better functional outcome in animal models of ischemia compared to untreated cells or injected dispersed. Furthermore, a large subset of data was obtained indicating graft/host interactions, vascularization of implanted construct and limited cell proliferation within the tissue layer. Mechanisms of gene delivery also remain an issue for better understanding of expression control so we set out to generate efficient methods for viral modification of stem cells to generate next-level cellular therapeutics.