The role of fibrocytes in fibrotic diseases of the lungs and heart

Fibrosis is the end result of a complex series of events that follow tissue injury and inflammation. Pathophysiologic fibrosis results in permanent scar formation, and can impair organ function. Fibrocytes are circulating, bone-marrow-derived progenitor cells that traffic from the bone marrow to the injured organ via the bloodstream, where they differentiate into fibroblasts and myofibroblasts, and play a pivotal role in both physiologic and aberrant fibrosis. In this review, we focus on the contribution of fibrocytes to fibrotic diseases of the lungs and the heart, including interstitial lung diseases, asthma, pulmonary hypertension, atherosclerosis and ischemic cardiomyopathy.