Kolbinger, A.A.KolbingerKestner, R.I.R.I.KestnerJencio, L.L.JencioSchäufele, T.J.T.J.SchäufeleVutukuri, R.R.VutukuriPfeilschifter, W.W.PfeilschifterScholich, KlausKlausScholich2023-01-252023-01-252022https://publica.fraunhofer.de/handle/publica/43437110.3390/cells111016592-s2.0-8513010359935626695Ischemic stroke is a highly prevalent vascular disease leading to oxygen-and glucose deprivation in the brain. In response, ischemia-induced neovascularization occurs, which is supported by circulating CD34+ endothelial progenitor cells. Here, we used the transient middle cerebral artery occlusion (tMCAO) mouse model to characterize the spatio-temporal alterations within the ischemic core from the acute to the chronic phase using multiple-epitope-ligand cartography (MELC) for sequential immunohistochemistry. We found that around 14 days post-stroke, significant angiogenesis occurs in the ischemic core, as determined by the presence of CD31+ /CD34+ double-positive endothelial cells. This neovascularization was accompanied by the recruitment of CD4+ T-cells and dendritic cells as well as IBA1+ and IBA1− microglia. Neighborhood analysis identified, besides pericytes only for T-cells and dendritic cells, a statistically significant distribution as direct neighbors of CD31+ /CD34+ endothelial cells, suggesting a role for these cells in aiding angiogenesis. This process was distinct from neovascularization of the peri-infarct area as it was separated by a broad astroglial scar. At day 28 post-stroke, the scar had emerged towards the cortical periphery, which seems to give rise to a neuronal regeneration within the peri-infarct area. Meanwhile, the ischemic core has condensed to a highly vascularized subpial region adjacent to the leptomeningeal compartment. In conclusion, in the course of chronic post-stroke regeneration, the astroglial scar serves as a seal between two immunologically active compartments-the peri-infarct area and the ischemic core-which exhibit distinct processes of neovascularization as a central feature of post-stroke tissue remodeling. Based on our findings, we propose that neovascularization of the ischemic core comprises arteriogenesis as well as angiogenesis originating from the leptomenigeal vasculature.enangiogenesisdendritic cellmicrogliamultiplex immunohistochemistrystrokeT-celljournal article