Regulation of MMP/TIMP by HUVEC transplantation attenuates ventricular remodeling in response to myocardial infarction.

Aims: We elucidated the therapeutic potential of human umbilical vein endothelial cells (HUVECs) for ameliorating progressive heart failure in a myocardial infarction (MI) rat model.

Main Methods: MI was induced by ligation of left anterior descending artery, and HUVEC was transplanted 1week after MI. Cardiac function was evaluated by echocardiography, and histological analyses were performed.

Key Findings: Phosphate-buffered saline (MI-V, n=5) or HUVEC (MI-HV, n=5) were injected into the border zone and infarcted area 7days after ligation of the left coronary artery in rats. The MI-HV group showed attenuation of left ventricular (LV) remodeling compared with the MI-V group. In the infarcted myocardium, a few of injected HUVEC was retained up to 28days. The ratios of matrix metalloproteinase (MMP)-2 or MMP-9 to tissue inhibitor of metalloproteinase (TIMP)-1 or TIMP-3 were decreased in the MI-HV group compared with the MI-V group. In vivo zymography analysis showed that HUVEC transplantation decreased the activities of MMP-2 and MMP-9. In immunohistochemistry, decreased MMP-2 and increased TIMP-1 and TIMP-3 expression were observed at 48h after HUVEC transplantation. These effects on MMP/TIMP balance were inhibited by L-NAME administration (an eNOS inhibitor, 10mg/kg). NOS inhibition decreased the protein expressions of TIMP-1 and TIMP-3 but did not change the protein expressions of MMP-2 and MMP-9.

Significance: Our data suggest that altered balance between MMP and TIMP by HUVEC transplantation contributed to attenuation of ventricular remodeling after MI via eNOS.