Our objective was to evaluate the safety and clinical efficacy of autologous M2 macrophage transplantation in nonacute stroke patients. We also evaluated whether the intrathecal administration of macrophages influences the production of cytokines by peripheral blood cells and whether the levels of cytokines correlate with stroke severity and responsiveness to cell therapy. In this study, 13 patients (12 males and 1 female with a median age of 63 years) diagnosed with ischemic ( n = 10) or hemorrhagic ( n = 3) stroke were subjected to cell transplantation therapy (study group). On average, 21.9 × 10⁶autologous M2 macrophages were injected intrathecally. Thirteen matched case-control stroke patients who did not receive cell therapy comprised the control group. We did not observe any serious adverse events (i.e., intrahospital mortality, neurological worsening, and seizures) related to the cell injection. One patient in the study group and two patients in the control group died during the 6-month follow-up period due to recurrent stroke. In the study group, the NIHSS score decreased from 11 to 6 ( p = 0.007) in 6 months after the therapy, whereas the patients in the control group showed a less pronounced neurological improvement (the NIHSS score decreased from 11 to 8, p = 0.07). The obvious positive response (the improvement of the NIHSS score ≥3) in the study group was observed in 75% versus 18% in the control group ( p_FET= 0.03). M2 cell introduction did not significantly affect the production of various cytokines. Nevertheless, pretreated levels of IL-8, IL-10, and IL-4 correlated with stroke severity. Moreover, responder patients had lower spontaneous production of IL-10, FGF-β, PDGF, VEGF, and higher stimulation indexes of IL-1β, TNF-α, IFN-γ, and IL-6 than nonresponders. These findings suggest that the intrathecal administration of autologous M2 cells in stroke patients is safe and leads to a better neurological recovery, which could be mediated through the immunomodulatory activity of M2 macrophages.

Apoptosis and subsequent removal of dead cells are an essential part of wound healing. Macrophages phagocytize apoptotic cells (efferocytosis) and contribute to the resolution of inflammation. However, their participation in fibrogenesis and the mechanisms of influence on this process remain unclear. In the present study, we focused on the fibrogenic properties of human monocyte-derived macrophages polarized in the M2 direction by interaction with apoptotic cells. We studied their influence on the proliferation ([3H]-thymidine incorporation), differentiation (by the expression of α-SMA, a myofibroblast marker) and collagen-producing activity (ELISA) of dermal fibroblasts compared to classically (LPS) and alternatively (IL-4) activated macrophages. Macrophages polarized by the interaction with apoptotic cells had a unique phenotype and profile of produced factors and differed from the compared macrophage subtypes. Their conditioned media promoted the proliferation of dermal fibroblasts and the expression of α-SMA in them at the level of macrophages stimulated by IL-4, while the stimulating effect on the collagen-producing activity was more pronounced compared to that of the other macrophage subtypes. Moreover, they are characterized by the high level of production of pro-fibrotic factors such as TIMP-1, TGF-β1 and angiogenin. Taken together, M2-like macrophages polarized by efferocytosis demonstrate in vitro pro-fibrotic activity by promoting the functional activity of dermal fibroblasts and producing pro-fibrotic and pro-angiogenic factors.

Objective: Cell-based technologies are considered to be a new approach for the treatment of cerebral palsy (CP). Given the potent anti-inflammatory activity and high regenerative potential of M2 macrophages, these cells may be a promising source for cell transplantation. To evaluate the safety and efficacy of autologous M2 macrophages, we performed an open-label, Phase I/II, non-controlled clinical trial in children with severe CP. Patients and methods: Fifty-seven children with severe CP, including 33 boys and 24 girls, with a median age of 4 years were enrolled in the study. The patients were treated with intrathecal administration of autologous M2 macrophages. The primary outcome measure was safety, and the secondary outcome measure was functional improvement in neurologic scales, including the 66-item Gross Motor Function Measure test, Peabody Developmental Motor Scale-Fine Motor test, Ashworth scale, Medical Resarch Council scale, and an easy-to-understand unified questionnaire for evaluation of cognitive functions in our modification. Results: Intrathecal introduction of M2 cells in a median dose of 11.2×10⁶ did not induce any serious adverse events either related with cell injection or during 5 years of follow-up. After 3 months, the Gross Motor Function Measure score increased from 19±4.5 to 77±7.8, the Peabody Developmental Motor Scale-Fine Motor test score improved from 0.9±0.23 to 4.4±0.51, and the Ashworth score decreased from 3.5±0.11 to 2.5±0.16. The assessment of cognitive functions revealed an increase from 1.22±0.24 to 3.98±0.95, and a reduction of seizure syndrome was registered. In addition, M2 injection was accompanied by an increased production of brain-derived neurotrophic factor (p_U=0.015). Conclusion: The data obtained suggest that cell therapy based on M2 macrophages is safe, does not induce any severe cell-related reactions or long-term side effects and comorbidities, and is accompanied by significant neurologic improvements in severe CP patients.