Being a Target for Glycation by Methylglyoxal Contributes to Therapeutic Efficacy of Injectable Collagen Hydrogels Post-Myocardial Infarction

Despite the advances in medical therapies for treating myocardial infarction (MI), morbidity and mortality rates remain high. Following MI, increased methylglyoxal (MG) production leads to the accumulation of advanced glycation end-products (AGEs), which contribute to adverse remodeling and to the deterioration of cardiac function. We previously reported that an injectable collagen type I hydrogel improves the repair and function of mouse hearts post-MI. Notably, we observed that the injected hydrogel was a target for MG-AGE glycation, and that there were less MG-modified proteins in the myocardium. In this study, we further evaluated this protective mechanism by pre-glycating the hydrogels and assessing their therapeutic efficacy for treating MI. In vitro experiments showed that the viability of macrophages was reduced when cultured with the glycated hydrogel in the presence of MG. In vivo, female C57BL/6 mice were randomly assigned to receive intramyocardial injections of one of three treatments: phosphate-buffered saline, normal collagen hydrogel, or MG-glycated hydrogel. After 28 days, echocardiography was performed to evaluate cardiac function, and hearts were harvested for immunohistochemistry. Our results showed that the MG-glycated hydrogel had a reduced treatment effect (greater scar size, fewer wound-healing macrophages, less viable myocardium and decreased cardiac function) compared to mice that received the normal collagen hydrogel. In summary, this study demonstrates that the ability of the collagen hydrogel to act as a target for glycation and remove MG from the environment contributes to its therapeutic effect in treating the post-MI heart.