Troponin T and I have been used to study myocardial cell damage due to angina and myocardial infarction. Angina is a condition in which there are sharp chest pains, usually associated with blocked arteries. Troponin T and I have also been used to study the effects transplant rejection, after a heart transplant surgery. Transplant rejection occurs when the new tissues are not accepted by the body’s own tissues and the new tissues are attacked. It is thought that rejection should lead to elevated levels of troponin. This experiment was designed to test whether cell damage due to rejection could be detected based on the levels of troponin. This would be important to determine if there is persistent damage to the cells. The researchers showed that there were indeed elevated levels of troponin to indicate cell damage. This information could be useful in determining how to decrease the risk of rejection of tissues when transplants occur

http://jama.ama-assn.org/content/284/4/457.full.pdf