Although transplanting mesenchymal stem cells (MSCs) can improve cardiac function and contribute to endothelial recovery in a damaged artery, natural MSCs may induce neointimal
hyperplasia by directly or indirectly acting on vascular smooth muscle cells (VSMCs).
Receptor activity-modifying protein 1 (RAMP1) is the component and the determinant of
ligand specificity of
calcitonin gene-related peptide (CGRP). It is recently reported that CGRP and its receptor involve the proliferation and the apoptosis in vivo and in vitro, and the exogenous RAMP1 enhances the antiproliferation effect of CGRP in VSMCs. Here, we investigated the effects of MSCs overexpressing the human
receptor activity-modifying protein 1 (hRAMP1) on heart function and artery repair in rabbit models of
myocardial infarction (MI) reperfusion and
carotid artery injury. MSCs transfected with a recombinant adenovirus containing the hRAMP1 gene (EGFP-hRAMP1-MSCs) were injected into the rabbit models via the ear vein at 24 h after
carotid artery injury and MI 7 days post-EGFP-hRAMP1-MSC
transplantation. The cells that expressed both enhance
green fluorescent protein (EGFP) and CD31 were detected in the
neointima of the damaged artery via immunofluorescence. EGFP-hRAMP1 expression was observed in the injured artery and infarcted myocardium by western blot analysis, confirming that the engineered MSCs targeted the injured artery and infarcted myocardium and expressed hRAMP1
protein. Compared with the EGFP-MSCs group, the EGFP-hRAMP1-MSCs group had a significantly smaller infarcted area and improved cardiac function by 28 days after
cell transplantation, as detected by
triphenyltetrazolium chloride staining and echocardiography. Additionally, arterial
hematoxylin-
eosin staining revealed that the area of the
neointima and the area ratio of intima/media were significantly decreased in the EGFP-hRAMP1-MSCs group. An immunohistological study showed that the expression of α-smooth muscle
antigen and
proliferating cell nuclear antigen in the
neointima cells of the carotid artery of the EGFP-hRAMP1-MSCs group was approximately 50% lower than that of the EGFP-MSCs group, suggesting that hRAMP1 expression may inhibit VSMCs proliferation within the
neointima. Therefore, compared with natural MSCs, EGFP-hRAMP1-engineered MSCs improved infarcted heart function and endothelial recovery from artery injury more efficiently, which will provide valuable information for the development of MSC-based
therapy.