Ischaemic heart disease, and its associated complications, is a leading cause of death worldwide. Improving outcomes for these patients has become a focal point in cardiac research, particularly given the human heart’s poor regenerative capacity. This, combined with pathological remodelling of the myocardium and resultant scar formation are major hurdles on the road to effective therapy.
Much progress has been made using animal models of myocardial infarction (MI), particularly mice (Mus musculus). Recently, an alternative mammalian model has been proposed, due to its higher capacity to resolve scar formation at the site of infarct. The spiny mouse (Acomys spp.) is a rodent with highly regenerative capacity and comparable cardiac anatomy and function to Mus. A trio of recently published papers (1-3) has studied the response of Acomys to MI, finding that while the initial stages post-injury show similarities, the intermediate and later stages of the response are very different. Acomys hearts display improved ejection fraction and decreased pathological remodelling, with higher survival rate, and cardiac functional stabilisation. When comparing the underlying cellular differences, the authors observed enhanced cell proliferation, increased angiogenesis, altered scar organisation, and reduced infarct size.
While these results are promising, little has been shown on factors typically associated with improved outcomes post-MI (e.g. immune response, cell clearance, oedema resolution) that might differ in Acomys mice. Future studies need to address these aspects to truly describe these mice as having enhanced myocardial preservation.
All in all, these studies position Acomys as a novel model to study myocardial infarction and scar formation/resolution. Understanding the mechanisms behind these improved outcomes post-MI may uncover novel experimental strategies to better understand ischemic heart disease.