The role of lymphatic vessels in the heart

Although cardiac lymphatic vessels have been described for over three centuries, research progress on the role of cardiac lymphatic vessels in regulating cardiac physiology and their disturbances in the pathogenesis of cardiac disease has progressed very slowly, largely due to technical challenges in developing both animal models and cardiac lymphatic vascular imaging technologies. This review summarizes evidence showing that blocking cardiac lymph flow may contribute to several forms of cardiac injury including cardiac lymphedema, cardiac valvular deformation, coronary arterial injury, conduction disturbances, myocardial injury, and poor heart performance in animal and human heart studies. Conversely, improving cardiac lymph flow may have beneficial effects on heart function after heart attack (myocardial infarction). In addition, this review summarizes recent hypotheses about the forces generating cardiac lymph flow, in which the role of both the subepicardial and mid-myocardial myocytes synchronized contractions causing lymph flow is discussed. Lastly, possible mechanisms of blood vessel injury caused by the failure of perivascular lymphatic remodeling are discussed.