171MESENCHYMAL STEM CELL TRANSPLANTATION ENHANCES FREQUENCY OF M2 POLARISED MACROPHAGES IN THE PERI-INFARCT REGION AND ATTENUATES SCAR FORMATION

• Published in: Interactive cardiovascular and thoracic surgery 2014-10, Vol.19 (suppl_1), p.S52-S52
• Main Authors: Neef, K., Deppe, A.C., Stamm, C., Kuhn, E.W., Scherner, M., Wittwer, T., Wahlers, T., Choi, Y.
• Format: Article
• Language: English
• ISSN: 1569-9293; 1569-9285
• DOI: 10.1093/icvts/ivu276.171

Objectives: Myocardial infarction leads to ventricular remodelling involving inflammation. M2 polarised macrophages, in contrast to M1 polarised macrophages, promote regenerative and anti-inflammatory processes. Since mesenchymal stem cells (MSC) influence the polarisation of macrophages, we tested the effects of MSC on M2 macrophage polarisation in an animal model of myocardial infarction. Methods: MSC were validated by flow cytometry and adipo-, chondro- and osteogenic differentiation in vitro. MSC were transplanted intramyocardially into cryo-infarcted murine hearts. After 1 and 2 weeks, hearts from MSC transplanted and sham operated animals were excised and analysed histologically for the size of the infarct scar and the distribution of M2 macrophages. Tissue from the peri-infarct region was analysed for M2 macrophage and inflammation-specific gene expression by quantitative real-time PCR (qPCR). Results: Scar sizes were similar in MSC and sham transplanted animals 1 week after operation. At 2 weeks the scar size was smaller in the MSC group (12.4 ± 2.3 mm2 vs 17.8 ± 1.8 mm2; P < 0.05) and an increase in M2 macrophages was observed histologically in the peri-infarct area. Furthermore, qPCR analyses revealed an increased expression of M2 macrophage-associated genes (CD206: +51.4 ± 8.8%; TSG6: +11.3 ± 1.2%; both P < 0.05) and anti-inflammatory cytokine IL-10 (+172.3 ± 18.2%; P < 0.01) in the peri-infarct region for the MSC group. Conclusion: Intramyocardial transplantation of MSC in the acute phase of myocardial infarction can attenuate the remodelling process and is linked to increased M2 polarisation of resident macrophages. This might represent an important step in understanding the underlying mechanisms of cardiac cell therapy.