Structural reconstruction of mouse acute aortic dissection by intravenously administered human Muse cells without immunosuppression

Abstract

Stanford type B-acute aortic dissection (type B-AAD) is often life-threatening without invasive surgery. Multilineage-differentiating stress enduring cell (Muse cells), which comprise several percent of mesenchymal stem cells (MSCs), are endogenous pluripotent-like stem cells that selectively home to damaged tissue and replace damaged/apoptotic cells by in-vivo differentiation. Mortality, aortic diameter expansion, cell localization, cell differentiation, and inflammation of the dissected aorta were evaluated in type B-AAD model mice intravenously injected with human-Muse cells, -elastin-knockdown (KD)-Muse cells, -human leukocyte antigen-G (HLA-G)-KD-Muse cells, or MSCs, all without immunosuppressant. Here, we show the Muse (50,000 cells) group has a lower incidence of aortic rupture and mortality of AAD compared with the MSC-50K (50,000 human-MSCs) and vehicle groups. Spectrum computed tomography in-vivo dynamics and 3-dimensional histologic analyses demonstrate that Muse cells more effectively home to the AAD tissue and survive for 8 weeks in the Muse group than in the MSC-750K (750,000 human-MSCs containing 50,000 Muse cells) group. Homing of Muse cells is impeded in the HLA-G-KD-Muse (50,000 cells) group. Differentiation of homed Muse cells into CD31(+) and alpha-smooth muscle actin (+) cells, production and reorganization of elastic fibers in the AAD tissue, and suppression of diameter expansion are greater in the Muse group than in the MSC-750K and elastin-KD-Muse (50,000 cells) groups. Intravenously administered Muse cells reconstruct the dissected aorta and improve mortality and diameter enlargement rates. Moreover, small doses of purified Muse cells are more effective than large doses of MSCs. HLA-G is suggested to contribute to the successful survival and homing of Muse cells. Acute aortic dissection (AAD) is a serious disease in which the largest artery in the body, called the aorta, enlarges and ruptures. Surgery is often required to prevent death. Cells called Muse cells have been injected into people during clinical trials to treat other diseases. In this study, we injected Muse cells into mice with dissected aorta. The cells accumulated in damaged parts of the aorta and strengthened the structure of the aorta, reducing the number of mice that died. If further research shows this treatment works in humans, this could enable AAD to be treated without surgery and potentially improve the treatment and survival of people with AAD. Takahashi et al. intravenously inject human Muse cells into model mice with Stanford type B acute aortic dissection. This effectively reduces diameter expansion rates, mortality and has a greater therapeutic effect than intravenous injection of large amounts of human mesenchymal stem cells.