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Transplanted fetal cardiomyocytes as cardiac pacemaker.
Arjang Ruhparwar1, Juergen Tebbenjohanns, Michael Niehaus
1Department of Thoracic and Cardiovascular Surgery, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover, Germany.
Summary
Transplanted fetal cardiomyocytes with a faster intrinsic rate acted as an ectopic pacemaker in dogs with heart failure. This study demonstrates electrical and mechanical coupling, offering potential for treating atrioventricular block.
Area of Science:
- Cardiology
- Regenerative Medicine
- Electrophysiology
Background:
- While transplanted cardiomyocytes integrate morphologically, their functional contribution to host myocardium is unproven.
- Previous studies lacked evidence of transplanted cell contribution to contraction and electrical excitation.
Purpose of the Study:
- To test if fetal cardiomyocytes with a higher intrinsic rate can function as an ectopic pacemaker.
- To demonstrate functional coupling between transplanted and host cardiomyocytes in vivo.
Main Methods:
- Fetal canine atrial cardiomyocytes were transplanted into the left ventricle of dystrophin-deficient dogs.
- Electrophysiological mapping and AV-node ablation were performed 3-4 weeks post-transplantation.
- Control group received fetal skin fibroblasts.
Main Results:
- Transplanted cells survived and integrated morphologically, expressing Dystrophin.
- Connexin 43 expression indicated gap junction formation between donor and host cells.
- Following AV-node ablation, a ventricular escape rhythm originated from the transplant site in the treatment group, unlike controls.
Conclusions:
- This study provides the first in vivo evidence of electrical and mechanical coupling between allogeneic donor cardiomyocytes and recipient myocardium.
- The findings suggest potential therapeutic applications for atrioventricular block using cardiomyocyte transplantation.