Cholecystokinin in cardiac myocytes

Cardiac expression of cholecystokinin (CCK) is a relatively new discovery. The expression in cardiac myocytes differs markedly from that of neuroendocrine cell expression in terms of posttranslational processing of proCCK. Only trace amounts of carboxyamidated CCK are produced in the healthy heart, which entails that a cardiac contribution to the bioactive CCK pool in circulation is limited. This difference ensures that intestinal CCK physiology does not overlap with that of the cardiac expression, albeit a local role cannot be ruled out. Instead, a large processing intermediate of proCCK dominates in cardiac tissue. Whether this organ-specific form or smaller fragments hereof, constitutes its own biology with possible effects within the cardiovascular system remains to be examined. A new methodology will also be needed to test the cardiac-specific proform as a possible biomarker of cardiovascular disease. Given the prevalence of heart failure, such a marker would be of major clinical value for either prediction, diagnosis, or monitoring of ongoing therapy.