Shift of Macrophage Phenotype Due to Cartilage Oligomeric Matrix Protein Deficiency Drives Atherosclerotic Calcification

Rationale:Intimal calcification is highly correlated with atherosclerotic plaque burden, but the underlying mechanism is poorly understood. We recently reported that cartilage oligomeric matrix protein (COMP), a component of vascular extracellular matrix, is an endogenous inhibitor of vascular smooth muscle cell calcification. Objective:To investigate whether COMP affects atherosclerotic calcification. Methods and Results:ApoE−/−COMP−/− mice fed with chow diet for 12 months manifested more extensive atherosclerotic calcification in the innominate arteries than did ApoE−/− mice. To investigate which origins of COMP contributed to atherosclerotic calcification, bone marrow transplantation was performed between ApoE−/− and ApoE−/−COMP−/− mice. Enhanced calcification was observed in mice transplanted with ApoE−/−COMP−/− bone marrow compared with mice transplanted with ApoE−/− bone marrow, indicating that bone marrow–derived COMP may play a critical role in atherosclerotic calcification. Furthermore, microarra...