Enhanced cardiac-specific differentiation of mouse embryonic stem cells via electrical stimulation

Cardiovascular diseases account for more deaths than any other disease. Cardiac tissue engineering has turned to stem cells as a renewable source of myocytes for use in tissue replacements. Existing methods for stem cell differentiation are non-specific, yielding low numbers of myocytes, with varying contraction frequencies and strengths. The goals of this project are to design novel experimental approaches, utilizing an electrical stimulation regimen, aimed at increasing the efficiency of cardiac differentiation from embryonic stem cells and generating cardiac myocytes/scyncithia with functional characteristics that more closely resemble native tissues. It has been found that parameters such as amplitude, duration and frequency of the electrical stimulus and the timing of its onset are critical factors for enhancement of cardiac differentiation.; Embryonic stem cells, subjected to an optimum regime of embryoid body formation via the hanging drop method followed by suspension culture and subsequent post plating on conductive slides with stimulation exhibit nearly 50% more cells differentiating toward the cardiac lineage compared to non-stimulated controls, as determined by microscopical analysis of the expression of ventricular marker myosin light chain-2v via immunohistochemistry. The spontaneous contractions in the stimulated cells begin up to one day earlier and have an average beat frequency close to that of the stimulus applied during differentiation. The spontaneously contracting regions have larger areas of contraction, which beat more rhythmically, as determined by videographic analysis. Data suggests that these improved myocytes may be better suited for applications in tissue engineered constructs, direct implantation into an ailing heart and for use in drug development models than those from other methods.