A combined cellular and surgical ventricular reconstruction therapeutic approach produces attenuation of remodeling in infarcted rats

A Modified Surgical Ventricular Reconstruction in Post-infarction Mice Persistently Alleviates Heart Failure and Improves Cardiac Regeneration

Objectives: Large ventricular aneurysm secondary to myocardial infarction (MI) results in severe heart failure (HF) and limits the effectiveness of regeneration therapy, which can be improved by surgical ventricular reconstruction (SVR). However, the conventional SVR procedures do not yield optimal long-term outcome in post-MI rodents. We hypothesized that a modified SVR procedure without aggressive purse string suture would persistently alleviate HF and improve cardiac regeneration in post-MI mice.

Methods: Adult male C57 mice were subjected to MI or sham surgery. Four weeks later, mice with MI underwent SVR or 2nd open-chest operation alone. SVR was performed by plicating the aneurysm with a single diagonal linear suture from the upper left ventricle (LV) to the right side of the apex. Cardiac remodeling, heart function and myocardial regeneration were evaluated.

Results: Three weeks after SVR, the scar area, LV volume, and heart weight/body weight ratio were significantly smaller, while LV ejection fraction, the maximum rising and descending rates of LV pressure, LV contractility and global myocardial strain were significantly higher in SVR group than in SVR-control group. The inhibitory effects of SVR on LV remodeling and HF persisted for at least eight-week. SVR group exhibited improved cardiac regeneration, as reflected by more Ki67-, Aurora B- and PH3-positive cardiomyocytes and a higher vessel density around the plication area of the infarcted LV.

Conclusions: SVR with a single linear suture results in a significant and sustained reduction in LV volume and improvement in both LV systolic and diastolic function as well as cardiac regeneration.

Safety and efficacy of global intracoronary administration of cardiosphere-derived cells or conditioned medium immediately after coronary reperfusion in rats

OBJECTIVE

Cardiosphere-derived cells (CDCs) have been shown to reduce infarct size after myocardial infarction (MI). In the present study we investigated the safety and efficacy of global intracoronary administration (GIA) of CDCs or CDC-conditioned medium (CM) immediately after reperfusion in a rat model of ischemia-reperfusion.

METHODS

CDCs were grown from myocardial biopsies obtained from male Wistar Kyoto rats (WKY). Female WKY rats underwent MI for 45minutes, followed by reperfusion for 1hour. Infarcted rats were randomized to receive GIA of CDCs (CDC group), CM (CM group) or vehicle (control group) immediately after the onset of reperfusion. Cell retention was quantified by PCR for the male specific SRY gene; area at risk (AR) and no reflow area (NR) were measured by histopathology. Cardiac function was evaluated by echocardiography at 1 and 2 months post-MI.

RESULTS

Cell retention at 1hour after GIA was 25.1% ±5.1. The myocardial AR and NR (measured at 1 hour post-reperfusion) were similar between groups [AR: 28.8% ±7.4 of LV mass in control vs 27.2% ±8 in CM vs 27% ±7 in CDCs group. NR: 7.0% ±3.3 in control vs 7.3% ±3.8 in CM vs 7.1% ±3.6 in CDCs]. One and 2 months post-MI, systolic function and LV volumes did not differ between control and CM groups.

CONCLUSION

Intracoronary administration of CDCs during the acute phase of MI, at the beginning of reperfusion, does not aggravate microvascular obstruction and results in high cell retention. Delivery of CM in the acute phase of MI did not confer long-term cardiac functional benefits.