Cardio-Hematopoietic Axis in Cardiac Injury and Repair: From Adaptation to Maladaptation

The cardiovascular and hematopoietic systems are functionally interconnected through the cardio-hematopoietic axis, a dynamic signaling network that governs hematopoietic responses following cardiac injury. Traditionally viewed primarily as a unidirectional pathway in which cardiac damage mobilizes bone marrow-derived cells to facilitate myocardial repair, emerging evidence now suggests a bidirectional model wherein cardiac-derived cues reciprocally influence hematopoietic stem and progenitor cell fate decisions within the bone marrow niche. This review synthesizes current insights into the mechanistic crosstalk between the injured heart and bone marrow, highlighting the mechanisms by which myocardial injury activates emergency hematopoiesis and immune cell mobilization to support cardiac repair, as well as how cardiac-derived inflammatory and neurohumoral signals remodel the bone marrow niche and reprogram hematopoietic stem cell lineage commitment toward a myeloid-biased, proinflammatory output that amplifies systemic inflammation that contributes to increased cardiovascular risk.