Abstract 10831: Adipose-Derived Regenerative Cells Implantation Alleviates Lymphedema via Augmentation of VEGF-C Mediated M2 Macrophage Mobilization
Introduction: We previously demonstrated that implantation of adipose-derived regenerative cells (ADRCs) augmented lymphangiogenesis and improved secondary lymphedema. Recently we also found M2 macrophage play an important role as lymphatic endothelial cell (LEC) progenitor in the pathological states. Accordingly, we investigated whether paracrine effect of ADRCs promotes mobilization of bone marrow (BM) derived M2 macrophage and contributes to therapeutic lymphangiogenesis for secondary lymphedema.
Methods and Results: ADRCs and mature adipocytes (MAs) were isolated from C57BL/6J mice. To examine therapeutic efficacy of ADRCs implantation in vivo, we have established a modified mouse model of tail lymphedema (n=24). One day after operation, mice were randomly divided into three groups (ADRCs implantation: 2×106 /mouse, MAs implantation: 2×106/mouse, or PBS injection). Four weeks after the treatment, lymphedema was significantly improved with regeneration of lymphatic network in the ADRCs group than in the other two groups(p<0.05). Cultured ADRCs secreted VEGF-C protein in vitro (p<0.05). In vivo study also revealed that ADRCs implantation augments the expression of VEGF-C mRNA at the edematous tissue and plasma VEGF-C levels at day5 (p<0.05). Lymphatic endothelial progenitor cell (LEPC) kinetic assay was performed using an anti-LYVE-1 Mab, as lymphatic endothelial cell marker, anti-CD11b Mab, as pan-macrophage marker, and anti-CD163 Mab, as M2 macrophage marker, by flow cytometry and immunohistochemical staining. Quantitative analysis revealed that the number of BM- and circulating- LEPCs was significantly higher in the ADRCs group than in the control group. Most of macrophages differentiated into LEC in the edematous tissue were polarized to M2 phenotype. A greater number of LYVE-1+/CD163+ M2 macrophages, a higher lymphatic capillary density (p<0.01) were observed at regenerative site in the ADRCs group compared to the other groups.
Conclusions: The mechanisms of therapeutic lymphangiogenesis by ADRCs implantation were not only sprouting of residual lymphatic vessels, but also mobilization and recruitment of M2 macrophage as LEPC.
- © 2012 by American Heart Association, Inc.