Transplants of adult stem cells with the aim of spurring regeneration from injury and age-related dsyfunction have been a going concern for some years now, at first only available through medical tourism. It was that state of affairs that finally pressured US regulators to begin permitting these treatments to take place inside the US. Absent the widespread use of stem cell transplants throughout the rest of the world, I'm sure that the FDA would be requesting more data and more studies still, while forbidding clinical applications of stem cell science. The bureaucrats there exist to put roadblocks in place, as they derive only risk from actually permitting any new treatment to move forward. Only when they are made to look backwards and foolish is there enough of a counterbalancing risk to enable significant movement. As for all entrenched systems of government regulation it is a shameful, squalid, and petty situation: this would be laughable if not for the great harms it causes through ensuring that medical progress is far slower and more expensive than it should be.
In any case, while adult stem cell therapies are a going concern, the same is far from true for the use of embryonic stem cells as a source of cells for therapeutic use. That line of work was quite effectively sabotaged by a combination of politics and inherent difficulty and is only now reaching milestones envisaged a decade ago. Much of the early energy and enthusiasm passed instead to research into cellular reprogramming, such as that involved in the creation of induced pluripotent stem cells that can be used to generate any type of cells on demand.
Nonetheless there are research groups working with human embryonic stem cells as the basis for regenerative medicine. Here is an example of heart cells sourced from embryonic stem cells producing regeneration in primate hearts:
Stem cell therapy can regenerate heart muscle in primates. The scientists on this and related projects are seeking way to repair hearts weakened by myocardial infarctions. This all-too-common type of heart attack blocks a major artery and deprives heart muscle of oxygen.
People who survive a severe episode often continue their lives in poor health because their hearts no longer work properly. The researchers hope eventually to restore such failing hearts to normal function. Their approach uses heart cells created from human embryonic stem cells. The researchers tested the possibility of producing enough of these cardiac muscle cells to remuscularize damaged hearts in a large animal whose heart size and physiology are human-like.
Pluripotent stem cells provide a potential solution to current epidemic rates of heart failure by providing human cardiomyocytes to support heart regeneration. Studies of human embryonic-stem-cell-derived cardiomyocytes (hESC-CMs) in small-animal models have shown favourable effects of this treatment. However, it remains unknown whether clinical-scale hESC-CM transplantation is feasible, safe or can provide sufficient myocardial regeneration.
Here we show that hESC-CMs can be produced at a clinical scale (more than one billion cells per batch) and cryopreserved with good viability. Using a non-human primate model of myocardial ischaemia followed by reperfusion, we show that that cryopreservation and intra-myocardial delivery of one billion hESC-CMs generates extensive remuscularization of the infarcted heart.
In contrast to small-animal models, non-fatal ventricular arrhythmias were observed in hESC-CM-engrafted primates. Thus, hESC-CMs can remuscularize substantial amounts of the infarcted monkey heart. Comparable remuscularization of a human heart should be possible, but potential arrhythmic complications need to be overcome.