Donor Stem Cells Can Aid Heart Regeneration

Matched donor iPSCs improve heart function and recovery after a heart attack in monkeys, but come with a side effect of transient arrythmia

One of the major challenges posed by a heart attack is the resulting damage to cardiovascular tissue which limits survival following the event. Stem cells may be a way to repair previously irreparable tissue loss and scarring, and scientists have been exploring the effect of injections of donor matched stem cells in monkeys.

The wonders of iPSCs

iPSCs stands for induced pluripotent stem cells, and these are formed from adult cells soaked in a specific cocktails of molecules that coax them back into a more primitive, stem cells state. This resets the clock to a degree, and allows them to behave in a similar manner to embryonic stem cells. The technology isn't 'perfect' yet, and there are concerns that cells taken from older individuals will remain 'old' and cause problems later on however. One solution to this issue is to use immune matched stem cells taken from another younger patient. 

Testing on monkeys

While monkeys aren't humans, they're far closer on the evolutionary tree than mice are, and are usually a good predictor of success in humans. In a study focusing on potential methods of heart regeneration, researchers formed cardiomyocyte cells (heart muscle cells) from iPSCs derived from immune matched monkeys. They then injected these into monkeys that had been subjected to a heart attack and observed significant cardiac regeneration. This unfortunately coincided with a period of arrhythmia, but the team noted that with careful management this was non-fatal and impermanent. 

Cardiomyocyte cells. Credit: arboreus/Flickr

To test this phenomenon further, the team prepared embryonic stem cells and formed the same cardiomyocyte cells. When they injected them in the same manner as the iPSC derived cells, they noted a similar recovery pattern, with the same non-fatal arrhythmia. 

"This post-transplant arrhythmia seems to be transient and non-lethal. All five recipients of iPSC-[cardiomyocytes] survived without any abnormal behavior for 12 weeks, even during the arrhythmia. So I think we can manage this side effect in clinic”

A faster solution

The benefit of donor matched cells is that they can be pre-made into stores of cells available to quick use in patients with heart failure. The time it would take to source cells from the patient themselves, turn those into stem cells and cardiomyocytes, and then grow a large enough population is often too long for those patients in poor health. Immune matched cells appear to confer significant recovery benefits in monkeys, and the research suggests they may be of similar benefit in humans. 

“They strengthen the case that a bank of pre-prepared matched [cells] could be used to treat patients, without relying on the long process of reprogramming and differentiating the patient’s own cells”

Read more at The Scientist