BackgroundTo improve the efficacy of bone marrow-derived mesenchymal stem cell (MSC) therapy targeted to infarcted myocardium, we investigated whether a self-setting silanized hydroxypropyl methylcellulose (Si-HPMC) hydrogel seeded with MSC (MSC+hydrogel) could preserve cardiac function and attenuate left ventricular (LV) remodeling during an 8-week follow-up study in a rat model of myocardial infarction (MI).Methodology/Principal FindingSi-HPMC hydrogel alone, MSC alone or MSC+hydrogel were injected into the myocardium immediately after coronary artery ligation in female Lewis rats. Animals in the MSC+hydrogel group showed an increase in cardiac function up to 28 days after MI and a mid-term prevention of cardiac function alteration at day 56. Histological analyses indicated that the injection of MSC+hydrogel induced a decrease in MI size and an increase in scar thickness and ultimately limited the transmural extent of MI. These findings show that intramyocardial injection of MSC+hydrogel induced short-term recovery of ventricular function and mid-term attenuation of remodeling after MI.Conclusion/SignificanceThese beneficial effects may be related to the specific scaffolding properties of the Si-HPMC hydrogel that may provide the ability to support MSC injection and engraftment within myocardium.

In patients aged 50-65 years undergoing AVR with the Carpentier-Edwards Perimount bioprosthesis, the expected valve durability was 19 years. Age was not a significant risk factor for SVD within this age group. Patient selection and attention to timing of reintervention may be determinants of long-term outcomes.