Submitted on March 1, 2008
Revised on September 15, 2008
Accepted on September 30, 2008
Enhanced Recovery of Mechanical Function in the Canine Heart by Seeding an Extracellular Matrix Patch with Mesenchymal Stem Cells Committed to a Cardiac Lineage
Irina A Potapova1, Sergey V Doronin1, Damon J Kelly1, Amy B Rosen1, Adam J. T. Schuldt1, Zhongju Lu2, Paul V Kochupura1, Richard B. Robinson3, Michael R. Rosen3, Peter R. Brink4, Glenn R Gaudette5*, and Ira S. Cohen4
1 Stony Brook University
2 State university of New York at Stony Brook
3 Columbia University
4 SUNY at Stony Brook
5 WPI
* To whom correspondence should be addressed. E-mail: gaudette{at}wpi.edu.
Objective: The need to regenerate tissue is paramount, especially for the heart which lacks the ability to regenerate after injury. The urinary bladder extracellular matrix (ECM), when used to repair a right ventricular defect, successfully regenerated some mechanical function. The objective of the current study was to determine whether the regenerative effect of ECM could be improved by seeding the patch with human mesenchymal stem cells (hMSCs) enhanced to differentiate down a cardiac linage. Methods: HMSCs were used to form three dimensional spheroids. Expression of cardiac proteins was determined in cells exposed to spheroid formation and compared to non-manipulated hMSCs. To determine if functional calcium channels were present, cells were patch clamped. To evaluate the ability of these cells to regenerate mechanical function, spheroids were seeded on ECM and then implanted into the canine heart to repair a full thickness right ventricular defect. Results: Many of the cells spreading from the spheroids expressed cardiac specific proteins, including sarcomeric alpha-actinin, cardiotin, and atrial natriuretic peptide, as well as the cell cycle markers cyclin D1 and PCNA. A calcium current similar in amplitude to that of ventricular myocytes was present in 16% of the cells. Cardiogenic cell seeded scaffolds increased regional mechanical function in the canine heart compared to unmanipulated hMSC seeded scaffolds. In addition, cells pre-labeled with fluorescent markers demonstrated myocyte-specific actinin staining with sarcomere spacing similar to that of normal myocytes. Conclusions: Spheroid derived cells express cardiac specific proteins and demonstrate a calcium current similar to adult ventricular myocytes. When these cells are implanted into the canine heart some of these cells appear striated and mechanical function is improved compared to unmanipulated hMSCs. Further investigation will be required to determine whether the increased mechanical function is due to differentiation of the cardiogenic cells to myocytes or to other effects.
