Chimerism in Human Hearts

Recent evidence suggests extracardiac progenitors can repopulate injured human hearts to replace damaged cells. One method of investigating this observation is to perform in-situ hybridization techniques in sex-mismatched heart transplants. We studied human female donor hearts that were transplanted into male recipients and assessed the degree of recipient cells with Y chromosome in-situ hybridization. Using this technique, our lab has recently published data showing evidence that extracardiac progenitor cells from the recipient replace damaged cardiomyocytes in transplanted hearts. (Circulation Research) Applying this technique, we also observed that major cell types in the heart are repopulated to a variable degree by recipient cells. However, the exact source of these progenitors is still under investigation.

We are currently underway to set up a mouse transplant model that would allow further investigation into the source of these cells. If we are able to define, select, and control these progenitor cells, the myocardial repair process can be enhanced, which can potentially lead to application in the clinical setting.