Human induced pluripotent stem cell-derived cardiomyocytes, in contrast to adipose tissue-derived stromal cells, efficiently improve heart function in murine model of myocardial infarction

Cell therapies are extensively tested to restore heart function after myocardial infarction (MI). Survival of any cell type after intracardiac administration, however, may be limited due to unfavorable conditions of damaged tissue. Therefore, the aim of this study was to evaluate the therapeutic effect of adipose-derived stromal cells (ADSCs) and human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) overexpressing either the proangiogenic SDF-1α or anti-inflammatory heme oxygenase-1 (HO-1) in a murine model of MI. ADSCs and hiPSCs were transduced with lentiviral vectors encoding luciferase (Luc), GFP and either HO-1 or SDF-1α. hiPSCs were then differentiated to hiPSC-CMs using small molecules modulating the WNT pathway. Genetically modified ADSCs were firstly administered via intracardiac injection after MI induction in Nude mice. Next, ADSCs-Luc-GFP and genetically modified hiPSC-CMs were injected into the hearts of the more receptive NOD/SCID strain to compare the therapeutic effect of both cell types. Ultrasonography, performed on days 7, 14, 28 and 42, revealed a significant decrease of left ventricular ejection fraction (LVEF) in all MI-induced groups. No improvement of LVEF was observed in ADSC-treated Nude and NOD/SCID mice. In contrast, administration of hiPSC-CMs resulted in a substantial increase of LVEF, occurring between 28 and 42 days after MI, and decreased fibrosis, regardless of genetic modification. Importantly, bioluminescence analysis, as well as immunofluorescent staining, confirmed the presence of hiPSC-CMs in murine tissue. Interestingly, the luminescence signal was strongest in hearts treated with hiPSC-CMs overexpressing HO-1. Performed experiments demonstrate that hiPSC-CMs, unlike ADSCs, are effective in improving heart function after MI. Additionally, long-term evaluation of heart function seems to be crucial for proper assessment of the effect of cell administration

Human Cardiac Mesenchymal Stromal Cells with CD105+CD34- Phenotype Enhance the Function of Post-Infarction Heart in Mice.

The aim of the present study was to isolate mesenchymal stromal cells (MSC) with CD105+CD34- phenotype from human hearts, and to investigate their therapeutic potential in a mouse model of hindlimb ischemia and myocardial infarction (MI). The study aimed also to investigate the feasibility of xenogeneic MSCs implantation.MSC isolated from human hearts were multipotent cells. Separation of MSC with CD105+CD34- phenotype limited the heterogeneity of the originally isolated cell population. MSC secreted a number of anti-inflammatory and proangiogenic cytokines (mainly IL-6, IL-8, and GRO). Human MSC were transplanted into C57Bl/6NCrl mice. Using the mouse model of hindlimb ischemia it was shown that human MSC treated mice demonstrated a higher capillary density 14 days after injury. It was also presented that MSC administrated into the ischemic muscle facilitated fast wound healing (functional recovery by ischemic limb). MSC transplanted into an infarcted myocardium reduced the post-infarction scar, fibrosis, and increased the number of blood vessels both in the border area, and within the post-infarction scar. The improvement of left ventricular ejection fraction was also observed.In two murine models (hindlimb ischemia and MI) we did not observe the xenotransplant rejection. Indeed, we have shown that human cardiac mesenchymal stromal cells with CD105+CD34- phenotype exhibit therapeutic potential. It seems that M2 macrophages are essential for healing and repair of the post-infarcted heart

Changes in a size of the scar and fibrosis in the post-infarction heart of a mouse 7 weeks after MI.

<p>(A B C) Representative images illustrating a post-infarction scar in the mouse heart in a (A) Sham group or after administration of (B) PBS^- or (C) CD105⁺CD34^- cells. The images are composed of several shots (magn. 4x). (D) The area of the post-infarction scar is significantly smaller after administration of CD105⁺CD34^- cells compared to the control group, in which PBS^- was administered (n = 14); **p<0.01 by the U Mann–Whitney test. (E F G) Representative images illustrating collagen (pink) deposited between the fibers of the muscle tissue (green) in the mouse heart in a (E) Sham group or after administration of (F) PBS^-, or (G) CD105⁺CD34^- cells. The sections with the greatest ratio of post-infarction scar to the whole stained area were used for examination (magn. 40x). (H) A statistically significant reduction of fibrosis was observed in the border area of the post-infarction scar after administration of CD105⁺CD34^- cells compared to the control group after administration of PBS^- (n = 14); **p<0.01 by the U Mann–Whitney test.</p

Therapeutic potential of CD105⁺CD34^- cells tested in a mouse model of hindlimb ischemia.

<p>(A) CD105⁺CD34^- cells treated mice demonstrated improved functional outcomes compared to the control mice (PBS^-) (n = 5; experiment repeated twice). (B) The number of blood vessels was higher at day 14 in mice after administration of CD105⁺CD34^- cells compared to the control mice after administration of PBS^- (n = 10; 10 muscles per group were analyzed, in each muscle 10 pictures were taken). *p<0.05 #p = 0.056 **p<0.01 by the Mann-Whitney U test.</p

Capillary density within the area of the post-infarction scar 7 weeks after MI.

<p>(A B C) Representative images presenting the number of blood vessels within the area of the post-infarction scar. Magn. 20x. (A) in mice after administration of PBS^- (B) in mice after administration of CD105⁺CD34^- cells. (C) Within the scar, a significant increase in the number of blood vessels in mice after administration of CD105⁺CD34^- cells compared to the control mice after administration of PBS^- was observed. n = 7; ** p<0.01 by the Student’s t-test.</p

Changes in left ventricular ejection fraction (LVEF) 6 weeks after the cells administration.

<p>LVEF increased by 5.75% between treated groups at 49 day. Day 0 –LVEF (baseline); day 7 –LVEF seven days after MI induction, the day of administration of CD105⁺CD34^- cells or PBS^-: day 49 –LVEF on the day of the collection of the hearts. PBS^-: n = 16; CD105⁺CD34^-: n = 18; **p<0.01; *p<0.05; # p = 0.0946. Comparisons between groups and within groups were performed by the one-way analysis of variance (ANOVA) with repeated measures with post-hoc Tukey tests.</p

Capillary density in the border area of the post-infarction scar 7 weeks after MI.

<p>(A B C) Representative images presenting the number of blood vessels in the border area of the post-infarction scar (magn. 20x) (A) in a Sham group, (B) in mice after administration of PBS^-, (C) in mice after administration of CD105⁺CD34^- cells. (D) In the area bordering the post-infarction scar a significant increase in the number of blood vessels in mice after administration of CD105⁺CD34^- cells compared to the control mice after administration of PBS^- was observed. n = 7; * p<0.05 by the Student’s t-test.</p

Cytokines and growth factors secreted by CD105⁺CD34^- cells <i>in vitro</i>.

<p>(A) An exemplary image of a membrane used for the analysis of 80 cytokines and growth factors secreted by CD105⁺CD34^- cells. (B) Densitometric analysis of 80 cytokines and growth factors secreted by CD105⁺CD34^- cells indicates that CD105⁺CD34^- cells secrete mainly IL-6, IL-8, and GRO molecules (n = 5).</p