MMP9 and angina pectoris: However, the results from our preclinical murine study showed that MNC-QQ cell therapy directly accelerated wound closure, maturation, and vascularization in both diabetic and euglycemic wounds by upregulating matrix metalloproteinase-9 and transforming growth factor-beta gene expression.23 Finally, although mild and transient AEs were frequent, severe AEs or development of emboli, malignant tumors, or angina pectoris did not occur during our trial.