eLife assessment
This study provides important findings on the distinct functions of resident and recruited macrophages during cardiac healing after myocardial ischemia. Using state-of-the-art fate-mapping models and genetic and pharmacological targeting approaches, the authors provide solid evidence that the absence of resident macrophages do not influence infarct size but instead alter the immune cell crosstalk in response to injury. However, the functional evaluation of resident macrophages is limited by potential off target effects in ∆FIRE mice. This study should be of interest to the fields of Development, Immunology and Cardiology.