Intended for collection and use of human cells, all procedures were approved by the institutional review boards from the Seoul National University Hospital and the Samsung Medical Center in compliance with the principles of Good Clinical Practice and the Declaration of Helsinki. == Cell Sheet Generation == We prepared human ONECs and human ATSCs intended for generating a cell sheet with neurovascular characteristics using previously explained methods7, 28, 29. ICH induction). At 4 weeks from the cell transplantation, cell survival, migration, and differentiation were evaluated. Hemispheric atrophy and neurobehavioral recovery were also compared between the groups. As a result, the cell sheet was rich in extracellular matrices and expressed neurotrophic factors as well as the markers for neuronal development. After transplantation, the cells successfully survived intended for 4 weeks, and a large portion of those migrated to the perihematomal site and differentiated into neurons and pericytes (20% and 30% of migrated stem cells, respectively). Transplantation of cell sheets alleviated hemorrhage-related hemispheric atrophy (p= 0. 042) and showed tendency intended Tazemetostat hydrobromide for improving functional recovery (p= 0. 062). Therefore , we concluded that the cell sheet transplantation technique might induce direct regeneration of neural tissue and might improve results of intracerebral hemorrhage. Key words: Cell sheet, Cell therapy, Intracerebral hemorrhage (ICH), Neurovascular progenitor, Transplantation == INTRO == Stroke is a great threat to human health, with high mortality and morbidity rates1. Intracerebral hemorrhage (ICH) accounts for 10%20% of all strokes; it has a higher Tazemetostat hydrobromide mortality rate (approximately 40%) and results in more severe sequelae compared to the other subtypes of stroke1. ICH treatment aims to minimize the expansion from the hematoma or alleviate the increased intracranial pressure in the acute stage. However , the outcomes of ICH have not significantly improved over the decades2, although early surgical treatments including decompressive craniectomy or hematoma evacuation have been recognized to be beneficial in selected situations35. Hence, cell therapy has been actively evaluated to regenerate the damaged neurons and ultimately improve the long-term outcomes611. However , the major mechanisms of their efficacy are limited to the degeneration of the inflammatory response and the modulation from the damaged site to a cytoprotective microenvironment, known as the bystander effect, rather than the direct migration from the stem cells and true regeneration from the damaged tissue7, 8, 1114. Therefore , further efforts have been designed to effectively deliver stem cells to the relevant sites, improve the viability of the transplanted stem cells, and induce direct tissue regeneration from stem cells, including scaffold-based cells, microtissue, and cell sheet technology12, 1517. A cell sheet, a confluent monolayer of cells grown in a cell culture dish, is a novel scaffold-free cell delivery system that can be easily manipulated considering the purpose of use, directly transplanted to the target site, and react in response to changes in their environment without causing any immunologic reaction16. Cell sheets have been successfully applied to a variety of tissues including the skin, cornea, myocardium, blood vessels, and muscle12, 15, 1827. A cell sheet study ideally requires a large animal model, but for ICH it has been limited owing to the lack of relevant large-animal models. Relatively recently, a canine physiologic model of ICH was established6, which has the next potent advantages over the previously used murine ICH model. First, compared to the murine ICH model with an intracerebral injection of collagenase7, 9, 11, the canine model induces ICH via the infusion of autologous blood under arterial pressure and is therefore more physiologic. Second, with the autologous blood infusion method, the volume of ICH and the disease severity can be easily homogenized among the animals. Third, the canine brain is bigger than the murine brain; therefore , it is more suitable intended for the transplantation of cell sheets that have approximately 6 cm2of surface area22. Fourth, with the canine model, a more detailed neurobehavioral test can be performed to access the comprehensive functional results. In the current study, we designed a composite cell sheet made of neural progenitors, derived from human olfactory neuroepithelial cells (ONECs), and vascular progenitors, from human corpulence tissue-derived stromal cells (ATSCs), to generate new neurovascular cells with trophic and regenerative support. We transplanted the composite cell sheet in the subacute stage in a canine model of ICH and evaluated its efficacy for direct neural regeneration at the relevant Rabbit Polyclonal to PIGX site and improving the histologic and clinical results of ICH. == MATERIALS AND METHODS == == Ethical Approval == All procedures were approved by the Institutional Pet Care and Use Committee (IACUC). Tazemetostat hydrobromide