Neurorestorative Therapy for Stroke

Mesenchymal stem cell (MSC) transplantation improves recovery from ischemic stroke in animals. We examined the feasibility, efficacy, and safety of cell therapy using culture-expanded autologous MSCs in patients with ischemic stroke. We prospectively and randomly allocated 30 patients with cerebral infarcts within the middle cerebral arterial territory and with severe neurological deficits into one of two treatment groups: the MSC group (n = 5) received intravenous infusion of 1 x 10(8) autologous MSCs, whereas the control group (n = 25) did not receive MSCs. Changes in neurological deficits and improvements in function were compared between the groups for 1 year after symptom onset. Neuroimaging was performed serially in five patients from each group. Outcomes improved in MSC-treated patients compared with the control patients: the Barthel index (p = 0.011, 0.017, and 0.115 at 3, 6, and 12 months, respectively) and modified Rankin score (p = 0.076, 0.171, and 0.286 at 3, 6, and 12 months, respectively) of the MSC group improved consistently during the follow-up period. Serial evaluations showed no adverse cell-related, serological, or imaging-defined effects. In patients with severe cerebral infarcts, the intravenous infusion of autologous MSCs appears to be a feasible and safe therapy that may improve functional recovery.

We recently demonstrated that marrow stromal cells (MSCs) augment collateral remodeling through release of several cytokines such as VEGF and bFGF rather than via cell incorporation into new or remodeling vessels. The present study was designed to characterize the full spectrum of cytokine genes expressed by MSCs and to further examine the role of paracrine mechanisms that underpin their therapeutic potential. Normal human MSCs were cultured under normoxic or hypoxic conditions for 72 hours. The gene expression profile of the cells was determined using Affymetrix GeneChips representing 12 000 genes. A wide array of arteriogenic cytokine genes were expressed at baseline, and several were induced >1.5-fold by hypoxic stress. The gene array data were confirmed using ELISA assays and immunoblotting of the MSC conditioned media (MSC(CM)). MSC(CM) promoted in vitro proliferation and migration of endothelial cells in a dose-dependent manner; anti-VEGF and anti-FGF antibodies only partially attenuated these effects. Similarly, MSC(CM) promoted smooth muscle cell proliferation and migration in a dose-dependent manner. Using a murine hindlimb ischemia model, murine MSC(CM) enhanced collateral flow recovery and remodeling, improved limb function, reduced the incidence of autoamputation, and attenuated muscle atrophy compared with control media. These data indicate that paracrine signaling is an important mediator of bone marrow cell therapy in tissue ischemia, and that cell incorporation into vessels is not a prerequisite for their effects.

We previously evaluated the short-term follow-up preliminary data of mesenchymal stem cells (MSCs) transplantation in patients with ischemic stroke. The present study was conducted to evaluate the long-term safety and efficacy of i.v. MSCs transplantation in a larger population. To accomplish this, we performed an open-label, observer-blinded clinical trial of 85 patients with severe middle cerebral artery territory infarct. Patients were randomly allocated to one of two groups, those who received i.v. autologous ex vivo cultured MSCs (MSC group) or those who did not (control group), and followed for up to 5 years. Mortality of any cause, long-term side effects, and new-onset comorbidities were monitored. Of the 52 patients who were finally included in this study, 16 were the MSC group and 36 were the control group. Four (25%) patients in the MSC group and 21 (58.3%) in the control group died during the follow-up period, and the cumulative surviving portion at 260 weeks was 0.72 in the MSC group and 0.34 in the control group (log-rank; p = .058). Significant side effects were not observed following MSC treatment. The occurrence of comorbidities including seizures and recurrent vascular episodes did not differ between groups. When compared with the control group, the follow-up modified Rankin Scale (mRS) score was decreased, whereas the number of patients with a mRS of 0-3 increased in the MSC group (p = .046). Clinical improvement in the MSC group was associated with serum levels of stromal cell-derived factor-1 and the degree of involvement of the subventricular region of the lateral ventricle. Intravenous autologous MSCs transplantation was safe for stroke patients during long-term follow-up. This therapy may improve recovery after stroke depending on the specific characteristics of the patients.