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Cell Sheets from Adipose-Derived Mesenchymal Stromal Accelerate Healing and Angiogenesis
Cell sheet (CS) technology has advantages for application in regenerative medicine as far as it allows effective and feasible delivery cells for therapeutic application.Cell sheets are minimal tissueengineered 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. This approach has been in our field of interest during last years and we have developed CS application from adult stem cells - mesenchymal (MSC) and c-kit+ cardiac stem cells (CSC) for stimulation of angiogenesis in ischemic skeletal muscle and infarcted myocardium, induction of wound healing and other clinically relevant models. Starting from wound healing in a rat model of deep defect of soft tissues we found that delivery of constructs from adipose-derived MSC significantly accelerated wound healing compared to suspended cells accompanied by higher engraftment rate of CS-delivered MSC compared to dispersed.We also successfully adopted the concept of gene delivery application to modify cells for sake of new therapeutic methods. Using viral delivery of growth factors allows to enhance MSC 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 decade 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 adenoassociated viruses (AAV) and baculovirus we managed express growth factors in MSC and 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 VEGFexpressing MSCs had better survival and resulted in higher perfusion and blood vessel counts at experiment’s endpoint.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. Overall our set of studies summarizes efforts to develop a next-level cell therapeutic combining feasible and effective delivery technique with viral modification as a way to enhance paracrine modality known to be crucial for MSC and their regenerative potential in numerous lesions affecting human population.
Study was supported by RFBR grant #17-04-01452 (cell culture and in vitro assays), partially- by RSF grant #16-45-03007 (animal test and histology) and used biomaterial biomaterial collected and preserved in the frame of the project “Scientific basis for national bank-depositary of living systems” (RSF agreement #14-50-00029) using the equipment purchased as a part of Lomonosov Moscow State University Program of Development.