Longevity Briefs: Regenerating The Damaged Heart With Exosomes

Longevity briefs provides a short summary of novel research in biology, medicine, or biotechnology that caught the attention of our researchers in Oxford, due to its potential to improve our health, wellbeing, and longevity.

Why is this research important: Heart attacks can permanently damage heart tissue, which disrupts the electrical patterns responsible for cardiac contraction. The result is chaotic electrical activity in the lower chambers of the heart, which causes them to twitch instead of pump and reduces their output with potentially fatal consequences. Treatments for this condition, which is called ventricular arrhythmia, include medications with serious side effects, implantable devices like pacemakers, and purposefully destroying parts of the heart to alter electrical signals.

The ideal treatment would involve fully repairing and restoring the damaged heart tissue to its original state. Unfortunately, adult heart muscle is unable to regenerate by itself.

What did the researchers do: In this study, researchers took two groups of laboratory pigs that had suffered heart attacks. One group received control injections, and the other received injections containing exosomes. Exosomes are balloon-like packages of signalling molecules and RNA that are released by some cells, and which can affect the activity and gene expression in other cells. In this study, researchers used exosomes produced by cardiosphere-derived cells, which are a cell type derived from cardiac stem cells and have been shown to promote regeneration of cardiac tissue.

Key takeaway(s) from this research: The hearts of the pigs receiving the exosomes, but not the control group, showed fewer signs of scarring, had improved heart rhythms and were protected against ventricular arrhythmia four to six weeks post-injection. This suggests that exosomes could one day be an effective treatment for heart attack patients that repairs and strengthens the heart, rather than inflicting further damage as commonly required currently.

Exosomes have various advantages in regenerative medicine compared with cell therapy (the injection or implantation of cells). They are more durable and easier to handle than living cells, don’t provoke much of an immune response, and should be safer than stem cell therapy due to their inability to replicate, which means they cannot form tumours.

Many questions still remain to be answered. Do the benefits of exosome therapy persist for longer than a few months? Do side effects eventually emerge? Do further injections increase the therapeutic effect? Additional studies are already planned, but so far the results seem promising.