Cell therapy with endothelial progenitor cells (EPCs) has emerged as a promising strategy to regenerate the brain after stroke. Here, we aimed to investigate if treatment with EPCs or their secreted factors could potentiate angiogenesis and neurogenesis after permanent focal cerebral ischemia in a mouse model of ischemic stroke. BALB/C male mice were subjected to distal occlusion of the middle cerebral artery, and EPCs, cell-free conditioned media (CM) obtained from EPCs, or vehicle media were administered one day after ischemia. Magnetic resonance imaging (MRI) was performed at baseline to confirm that the lesions were similar between groups. Immunohistochemical and histological evaluation of the brain was performed to evaluate angio-neurogenesis and neurological outcome at two weeks. CM contained growth factors, such as VEGF, FGF-b and PDGF-bb. A significant increase in capillary density was noted in the peri-infarct areas of EPC- and CM-treated animals. Bielschowsky’s staining revealed a significant increase in axonal rewiring in EPC-treated animals compared with shams, but not in CM-treated mice, in close proximity with DCX-positive migrating neuroblasts. At the functional level, post-ischemia forelimb strength was significantly improved in animals receiving EPCs or CM, but not in those receiving vehicle media. In conclusion, we demonstrate for the first time that the administration of EPC-secreted factors could become a safe and effective cell-free option to be considered in future therapeutic strategies for stroke.

In solid-state ${}^2\mathrm{H}$ NMR of fluid lipid bilayers, quasielastic deformations at MHz frequencies are detected as a square-law dependence of the nuclear spin-lattice ${(R}_{1Z})$ relaxation rates and order parameters ${(S}_{\mathrm{CD}}).\mathrm{}$ The signature square-law slope is found to decrease progressively with the mole fraction of cholesterol and with the acyl chain length, due to a stiffening of the membrane. The correspondence to thermal vesicle fluctuations and molecular dynamics simulations implies that a broad distribution of modes is present, ranging from the membrane size down to the molecular dimensions.