The search for curative therapies for heart disease has prompted a look at stem cells as a possible solution. What do the first clinical trials tell us?
Is there such a thing as a “heart failure pandemic”? To be sure, heart disease isn’t contagious, but with an aging population and as more people survive an initial cardiovascular insult (only to develop chronic heart failure later), millions of people around the globe are in need of cardiac protection and healing.
Advances in pharmacology and medical care have reduced mortality and improved quality of life. When patients could still benefit more from therapeutic interventions, perhaps stem cells fit the bill. After all, regenerative medicine may be just what the doctor ordered when heart attacks and other insults damage hearts.
Indeed, several studies have investigated whether stem cell therapy is useful for heart disease. The original approach was to use unselected progenitor cells that were taken from bone marrow and expanded ex vivo. Preclinical studies demonstrated that bone marrow-derived mononuclear stem cells (BMMNCs) were integrated into heart tissues when transplanted after an acute myocardial infarction (AMI). It was shown that donor-derived cells indeed differentiated into cardiomyocytes and endothelial cells.
On the basis of the initial promising data, several clinical trials were enacted in which BMMNCs were injected into an affected artery after an AMI. Some studies indicated a positive effect, but many others reported no change. Investigations have also looked into the potential benefit of BMMNCs for patients with heart failure. The results are split: One study showed some promise, while another detected no advantage over the control group.
What gives? In a review of the data, authors pointed out that differences in study parameters, including differences in handling and delivery – as well as patient selection – could complicate matters. As a step forward, the authors argue that robust quality control standards may make for a clearer picture. Previous divergences in cell isolation approaches, incubation times before delivery, and number of cells used mean that it can’t be assumed that there was equivalence among the stem cell products in each investigation.
On a positive note, these experiences with several thousand patients have provided lessons on designing future studies. And it is no small thing that the safety of this type of approach has been demonstrated. In Part 2, we will examine how advances in stem cell experimentation have paved the way for exciting “next generation” stem cell therapies encompassing many facets of life science research.
If your heart is in stem cell research, we invite you to consider HemaCare as your provider of stem cells.
1. Behfar, A et al. Cell therapy for cardiac repair -- lessons from clinical trials. Nat. Rev. Cardiol. April 2014;11:232-246.