Use of human embryonic stem cell derived-mesenchymal cells for cardiac repair

Abstract

Human mesenchymal stem cells (hMSC) have proven beneficial in the repair and preservation of infarcted myocardium. Unfortunately, MSCs represent a small portion of the bone marrow and require ex vivo expansion. To further advance the clinical usefulness of cellular cardiomyoplasty, derivation of "MSC-like" cells that can be made available "off-the-shelf" are desirable. Recently, human embryonic stem cell-derived mesenchymal cells (hESC-MC) were described. We investigated the efficacy of hESC-MC for cardiac repair after myocardial infarction (MI) compared to hMSC. Because of increased efficacy of cell delivery, cells were embedded into collagen patches and delivered to infarcted myocardium. Culture of hMSC and hESC-MCs in collagen patches did not induce differentiation or significant loss in viability. Transplantation of hMSC and hES-MC patches onto infarcted myocardium of athymic nude rats prevented adverse changes in infarct wall thickness and fractional area change compared to a non-viable patch control. Hemodynamic assessment showed that hMSCs and hES-MC patch application improved end diastolic pressure equivalently. There were no changes in systolic function. hES-MC and hMSC construct application enhanced neovessel formation compared to a non-viable control, and each cell type had similar efficacy in stimulating endothelial cell growth in vitro. In summary, the use of hES-MC provides similar efficacy for cellular cardiomyoplasty as compared to hMSC and may be considered a suitable alternative for cell therapy.

Figure 1

hMSCs and hES-MCs respond similarly in 3D culture. A) hMSCs and hES-MCs displayed similar potency over 3 d. B) hES-MCs maintained a higher proliferative capacity than hMSCs over 3 d. C) hES-MCs and hMSCs displayed no difference in viability over 3 d. D) Patch compaction was similar between hMSCs and hES-MCs.

Figure 2

hMSCs and hES-MCs improve cardiac remodeling and function after myocardial infarction. A) Left ventricle blood pool fractional area change (FAC), B) left ventricular end diastolic diameter and C) infarct wall thickness were significantly improved after hMSC and hES-MC treatments as compared to MI and non-viable (NV) patch controls (*p < 0.05). Representative echocardiographic M-mode images showing LV function and properties for MI control (D), NV patch control (E), hMSC patch (F) and hES-MC (G). Invasive hemodynamic analysis for H) Left ventricle end diastolic pressure (EDP), I) +dP/dt and J) −dP/dt show improvement in diastolic parameters with no change in systolic parameters after hMSC and hES-MC patch application compared to MI and NV patch controls (*p < 0.05).

Figure 3

No change in infarct size with cardiac patch transplantation. Infarct size was determined by measuring the infarct midline circumference of Masson’s Trichrome stained tissue sections. Analysis revealed no change in infarct size four weeks after initial LAD ligation when comparing MI controls, hearts treated with MSC patches, or hearts treated hES-MC patches.

Figure 4

Application of hES-MC patches improves neo-vessel formation. A) hMSC and hES-MC applications increase neo-vessel formation compared to controls (*p < 0.05). B–D). Neo-vessel presence was detected using isolectin B4 and appears red (white arrows). DAPI (blue) was used as a nuclear counter stain (Magnification 40X). E) Myofibroblast abundances were unchanged between groups (F–H) Anti-αSMA (green) was used to detect myofibroblasts (10X).

Figure 5

Angiogenic growth factor mRNA abundances varied in hMSC and hES-MC progenitor cells: A) Vascular Endothelial Growth Factor (VEGF; *p < 0.05) B) CXCL1 (*p < 0.05) C) Angiogenin (ANG) and D) Platelet Derived Growth Factor-B (PDGF-B; *p < 0.05).

Figure 6

hMSC and hES-MC conditioned media support endothelial cell proliferation. Exposure of hMVEC-C to hMSC or hES-MC conditioned media results in increased relative cell counts compared to a maintenance media control (*p < 0.01).