Authors:
Satsuki Yamada, Timothy J. Nelson, Ruben Crespo, Carmen Terzic, Xiao Ke Liu, Takashi Miki, Susumu Seino, Atta Behfar, Andre Terzic
Summary:
Pathogenic causes underlying non-ischemic cardiomyopathies are increasingly resolved, yet repair therapies for these commonly heritable forms of heart failure are lacking. A case in point is human dilated cardiomyopathy 10 or CMD10 (OMIM #608569), a progressive organ dysfunction syndrome refractory to conventional therapies and linked to mutations in cardiac ATP-sensitive (KATP) channel subunits. Embryonic stem cell therapy demonstrates benefit in ischemic heart disease, but the reparative capacity of this allogeneic regenerative cell source has not been tested in inherited cardiomyopathy. Here, in a Kir6.2 knockout model lacking functional KATP channels, we recapitulated under the imposed stress of pressure overload the gene-environment substrate of CMD10. Salient features of the human malignant heart failure phenotype were reproduced, including compromised contractility, ventricular dilatation and poor survival. Embryonic stem cells were delivered through epicardial route into the left ventricular wall of cardiomyopathic stressed Kir6.2 null mutants. At 1 month of therapy, transplantation of 200,000 cells/heart achieved teratoma-free reversal of systolic dysfunction, electrical synchronization, and halted maladaptive remodeling thereby preventing end-stage organ failure. Tracked using the lacZ reporter transgene, stem cells engrafted into host heart. Beyond formation of cardiac tissue, positive for Kir6.2, transplantation induced cell cycle activation and halved fibrotic zones normalizing sarcomeric and gap junction organization within remuscularized hearts. Improved systemic function induced by stem cell therapy translated into increased stamina, absence of anasarca, and benefit to overall survivorship. Embryonic stem cells thus achieve functional repair in non-ischemic genetic cardiomyopathy, expanding indications to the therapy of heritable heart failure.
Source:
Stem Cells; (07/31/08)