Generation of vasculogenic progenitor cells from human induced pluripotent stem cells for the treatment of cardiovascular diseases

Abstract

Pluripotent stem cells hold great promise in regenerative medicine. Theoretically, a variety of tissues can be generated from this progeny. The production of tailor-made stem cells for individualized patient treatment is the ultimate goal of stem cell based therapy. Human induced pluripotent stem cells (iPSCs) hold the precious key to success and promote the clinical application of stem cells. By reprogramming somatic cells, pluripotent stem cells can be generated in a patient-specific manner and subsequently differentiated into specific tissue for regeneration. Nonetheless exposure of hiPSCs to animal feeder cells and serum during generation and maintenance imposes a risk of transmitting animal pathogens to human subjects, thus hindering their potential therapeutic application. In addition, the efficacy of iPSC generation is < 1% of total somatic cells used. The first part of the study focused on the development of improved methods to produce a more efficient xenogen-free culture system to produce more clinically compatible iPSCs.

Specific tissue or cells derived from stem cells may offer a solution and cell therapy using endothelial cells and their progenitors may be possible in treatment of severe cardiovascular diseases. In theory, endothelial cells can be generated from different sources of progenitor cells although no direct comparison of these various derived endothelial cells (ECs) has been reported. Thus in the second part of the study, the functional and physiological properties of BM, ESC and iPSC-ECs will be evaluated to determine their therapeutic potential in ischemic disease. A mouse hind limb ischemia model was used to assess and monitor neovascularization by the derived ECs. The results can provide further insight to evaluate the possibility of using iPSCEC as the cell source for patient-specific treatment.

Use of pluripotent stem cells is a promising approach in therapeutic angiogenesis although numerous hurdles continue to hamper their widespread clinical use. Conditioned medium derived from progenitor cells may be another possible strategy in the treatment of ischemic diseases such that direct cell transplantation is avoided.

Conditioned media produced from ex vivo culture of endothelial cells contain a combination of angiogenic factors that can be applied to promote neovascularization in ischemic tissue. Nonetheless the efficacy of this angiogenic application is unknown. The third part of the study focused on the potential application of EC-derived conditioned media in the treatment of ischemic disease using a mouse hind limb ischemia model. Some cardiovascular risk factors such as diabetes might affect endothelial cell function such that autologous application of ECs and their conditioned media is not feasible. A human embryonic stem cell line may offer and alternative means to obtain stable quality ECs and conditioned medium for therapeutic use.

In summary, advances in stem cell technology hold great promise for the treatment of cardiovascular disease, further improved by the generation of patient-specific stem cells using iPSC technology. Vascular cells can be generated from different sources of stem cells with similar angiogenic properties and may be used in the treatment of ischemic diseases.