A medical research group from Miami Miller School of Medicine has examined the safety of transendocardial stem cell injections with a patient’s own bone marrow stem cells in patients with ischemic cardiomyopathy.
Ischemic cardiomyopathy is the most common type of “dilated cardiomyopathy,” which is a fancy way of saying that the heart enlarges in its failing struggle to supply the body with blood. The enlarged heart has more heart muscle to feed with oxygen, but because the heart enlarges faster than the blood vessels remodel, large portions of the enlarged heart are left without adequate blood supply, and the result is and oxygen deficit, also known as “ischemia.” In patients with ischemic cardiomyopathy, the heart’s ability to pump blood is decreased because the heart’s main pumping chamber, the left ventricle, is enlarged, dilated and weak. Usually, heart ischemia also results from coronary artery disease and heart attacks.
The symptoms of ischemic CM include shortness of breath, swelling of the legs and feet (edema), Fatigue (feeling overly tired), inability to exercise, or carry out activities as usual, angina (chest pain or pressure that occurs with exercise or physical activity and can also occur with rest or after meals), weight gain, cough and congestion related to fluid retention, palpitations or fluttering in the chest due to abnormal heart rhythms (arrhythmia), dizziness or light-headedness, and fainting (caused by irregular heart rhythms, abnormal responses of the blood vessels during exercise, without apparent cause).
Clearly an effective regenerative treatment of ischemic cardiomyopathy (ICM) would address of the needs of some of these patients. Bone marrow transplants into the heart have been tested as treatments and the stem cells were directly injected into the heart muscle (see Williams AR, et al., Circ Res. 2011;108(7):792-796; and Losordo DW, et al., Circ Res. 2011;109(4):428-436). Both of these studies, however used mononuclear cells from bone marrow. Mononuclear cells refer to white blood cells from bone marrow and it includes a wide variety of stem cells, progenitor cells, and other mature white blood cells, but excludes red blood cells or platelets, which have no nuclei.
In order to determine if mesenchymal stem cells were also safe for this type of treatment, Alan W. Haldman and his colleagues from the laboratory of Joshua M. Hare tested 65 patients who suffered from ICM and compared injection of mesenchymal stem cells (n = 19) with placebo (n = 11) and bone marrow mononuclear cells (n = 19). Patients were followed up to one year after their procedures.
To measure serious adverse effects of the procedure, all patients were evaluated at 30 days post-procedure. Severe adverse effects includes death, heart attack, stroke, hospitalization for worsening heart failure, perforation of rupture of the heart, tamponade (compression of the heart due to a collection of fluid around it), or sustained ventricular arrhythmias.
None of the patients in this study showed any severe adverse events up to day 30, and up to 1 year after the procedure, 31.6% of the bone marrow mononuclear and mesenchymal stem cell groups had some sort of serious adverse event, and 38.1% of the placebo group had serious adverse events.
Over one year, the Minnesota Living with Heart Failure score, which is a measure of the quality of life of a heart patient, improved with the mesenchymal stem cell and bone marrow cells but not with the placebo. Also, the 6-minute walk distance increased in the mesenchymal stem cell group, but none of the other groups when the baseline time was compared with the six-month and 12-month trials.
Also, the size of the heart scar showed greater shrinkage in the mesenchymal stem cell group than in the other groups.
And if a more visual way to view this would help, here is the heart of one particular patient. Notice the shrinkage in the red area, which represents the scarred area, after one year.
The authors concluded from this study that these “results provide the basis for larger studies to provide definitive assessment of safety and to assess efficacy of this new therapeutic approach.” Mesenchymal stem cells might certainly provide a way to treat ICM patients. Also, if the patient’s bone marrow is of poor quality as a result of their poor health, then mesenchymal stem cells from a donor might provide healing for these patients. For now, I say, “bring on the larger trials!!”