Transplanted Induced Pluripotent Stem Cells Improve Cardiac Function and Induce Neovascularization in the Infarcted Hearts of db/db Mice

Abstract

Recently, we proclaimed that induced pluripotent stem (iPS) cells generated from H9c2 cells, following transplantation into infarcted nondiabetic mice, can inhibit apoptosis and differentiate into cardiac myocytes. iPS cells can be an ideal candidate to expand regenerative medicine to the clinic. Therefore, examining the wide range of their potential to differentiate into neovascular cell types remains a major interest. We hypothesized that transplanted iPS cells in the infarcted diabetic db/db and nondiabetic mice can differentiate into vascular smooth muscle (VSM) and endothelial cells (ECs) as well as activate endogenous c-kit progenitor cells to enhance neovascularization along with improved cardiac function. We transplanted intramyocardially 50,000 iPS cells in the peri-infarct zone of infarcted db/db and C57BL/6 mice and hearts were examined at D14 post-MI. Cardiac function was examined using echocardiography. Our data implies that there was a significant (p < 0.001) increase in VSM and ECs in the infarcted heart following iPS cell transplantation compared with MI and sham groups in both db/db and C57BL/6 animals. Furthermore, the MI+iPS cell transplanted group also displayed a significant (p < 0.001) increase in c-kit(+ve) activated VSM and ECs confirmed with combined stainings of c-kit and cell specific markers, compared with respective controls. Next, our histology data in the MI+iPS cell group also establishes a significant (p < 0.05) increase in coronary artery vessels compared with MI, suggesting neovascularization. Furthermore, our data demonstrates significant improved cardiac function following iPS cell transplantation compared with MI. Overall increased neovascularization in the infarcted db/db and C57BL/6 mice is associated with improved cardiac function following iPS cell transplantation.

A CD63+ve/c-kit+ve stem cell population isolated from the mouse heart

“…To verify whether treatment with ES-TIMP-1-CM or TIMP-1 can trigger CSC differentiation into cardiac myocytes, VSMs, and/or ECs in vitro, CD63 ?ve /c-kit ?ve cells were stained with either sarcomeric (Src) a-actin, smooth muscle (SM) a-actin, or CD31, respectively [9]. After 1 h incubation in NGS, cells were incubated with rabbit anti-CD31 monoclonal antibody (1:25, Santa Cruz Biotechnologies) prepared in 10 % NGS, followed by FITCconjugated goat anti-rabbit IgG secondary antibody (1:50, Invitrogen) for 60 min.…”

Bioluminescent Imaging of Genetically Selected Induced Pluripotent Stem Cell-Derived Cardiomyocytes after Transplantation into Infarcted Heart of Syngeneic Recipients

“…Cellular replacement approaches hold great promise for the treatment of this disease. Embryonic stem cells (ESC) [2], [3], induced pluripotent stem cells (iPSC) [4], [5], parthenogenetic stem cells [6] and their cardiomyocyte (CM) derivatives [7]–[12], as well as cardiac precursor cells [13], [14] and autologous adult stem cells [15], [16], have been shown to exert beneficial effects on the function of the injured heart after transplantation. However, only contractile CM are capable of electromechanical coupling with the host heart tissue, thereby contributing to its pump function [9], [12], [17].…”

Generation of electrophysiologically functional cardiomyocytes from mouse induced pluripotent stem cells

“…However, unpurified Flk1-positive cells formed teratomas after injection into the hearts of our AMI mouse models; therefore it is unsafe to inject incompletely differentiated iPS cells into the heart. Expression of the Yamanaka factors was silenced in the iPS cells and was not re-activated during formation of iPSC-CMs (Supplemental Figure 1), so engrafts derived from more mature cells seemed to be safe [43]. However, this raised another important issue of whether iPS cell-derived cardiac myocytes would couple with host cells successfully.…”