Hematopoietic Loss of Y Chromosome Leads to Cardiac Fibrosis and Dysfunction and is Associated with Death due to Heart Failure

Hematopoietic mosaic loss of Y chromosome (mLOY) is associated with increased risk of mortality and a variety of age-related diseases in men, but causal and mechanistic relationships have yet to be established. Here it is shown that mice reconstituted with bone marrow cells lacking the Y chromosome display increased mortality and age-related profibrotic pathologies including a progressive decline in cardiac function. Accelerated cardiac dysfunction and fibrosis were also observed in younger mice subjected to a pressure-overload model of heart failure. Bone marrow-derived, cardiac macrophages lacking the Y chromosome exhibited polarization toward a more fibrotic and less inflammatory phenotype. Treatment with a TGFb1 neutralizing antibody led to greater amelioration of heart failure in mice reconstituted with mLOY compared to wild-type bone marrow. Consistent with these data, a prospective study in men revealed that mLOY in blood is associated with an increased risk for cardiovascular disease and heart failure-associated mortality. Together, these results indicate that hematopoietic mLOY contributes to heart failure in men. Overall design: Cardiac Leukocytes, Control BMT, TAC, scRNAseq and Cardiac Leukocytes, LOY BMT, TAC, scRNAseq