Despite progress in cardiovascular research, cardiac pathology continues to be one of the most common causes of morbidity and mortality in the world. Stem cell-based therapy has been recognized as an innovative strategy for the repair, regeneration and functional recovery of the myocardium, hence, once the animal research stage has been overcome, most clinical trials aimed at evaluating the safety and effectiveness of regenerative medicine in cardiovascular diseases have focused on angina pectoris, myocardial infarction and chronic cardiomyopathy. Although the current evidence of benefit is not conclusive, the evidence in favor of favorable results is growing.
In some cases, stem cell therapy can provide an effective treatment or alternative for diseases or disorders for which there is no effective treatment. Because these cells are capable of dividing into a wide range of lineages and tissues, they can be used to treat various diseases by repairing, replacing, and regenerating tissues.
It is unclear how umbilical cord mesenchymal stem cells act on the heart, but previous studies have shown that they possess an anti-apoptotic effect. The induced cardiomyocytes can form discs interspersed with myocytes from the host cells, creating a functional syncytium that will help contract the heart. Mesenchymal stem cells can improve cardiac function and reduce damage caused by cardiovascular disease, since they stimulate endogenous repair mechanisms, the regulation of the immune response, tissue perfusion and the proliferation of the resident heart rate, thereby improving cardiac function and reducing damage severity.
Refractory angina
This syndrome, characterized by persistent angina despite standard medical treatment, is often not revascularized due to diffuse coronary lesions or severe comorbidities.
In 2017, a review included 13 clinical studies, with 1061 patients and 12 months of follow-up on average, indicating cell therapy has emerged as a tool for managing these patients. Although the available data are inconclusive, the authors conclude that stem cell-based therapy could be a viable addition to conventional treatment options for refractory angina, given the paucity of therapeutic alternatives.
There was a reduction in mortality at two years after a meta-analysis in 2018, involving 304 patients, showed improved exercise tolerance and reduced angina attack frequency at three, six and 12 months. An additional meta-analysis published in March 2019, involving 526 patients monitored for 14 months, showed that patients treated with stem cells had fewer serious adverse effects, fewer deaths, fewer angina attacks, and fewer antianginal medications than those treated with conventional management.
A third meta-analysis from 2019, with 269 patients and 15 months of follow-up on average, reports the following results: decreased all-cause mortality, decreased frequency of angina and increased exercise time, with no increase in adverse reactions.
Cardiomyopathy (ischemic and non-ischemic)
Despite optimal medical and surgical management, many patients with heart failure undergo long-term myocardial remodeling that does not allow them to restore their ventricular function. This is because current treatment protocols cannot reverse the loss of cardiomyocytes due to cardiomyopathy. Since inflammatory responses continue over time as a central mechanism in the development of heart failure, it was of interest to investigate the anti-inflammatory, antifibrotic, and immunomodulatory properties of stem cells in patients with ischemic and non-ischemic cardiomyopathy.
In a review of five clinical studies published between 2017 and 2018, including 605 patients, the authors conclude that cell therapy is safe, causes immunomodulatory effects, improves functional capacity, and adds clinical benefits to standard therapies. According to them, the results are promising, and further evidence strengthening is recommended.
Based on a meta-analysis published in May 2019, involving 20 investigations and 1418 patients evaluated for an average of 21 months, stem cells improved cardiac function indicators (LVEF and LVESV), walking distance, functional classification of heart failure, quality of life, and mortality as compared to controls. Hospitalizations and serious adverse events were not different from those in the control group.
In a recent review of 9 studies involving 612 patients with heart failure, improvement was found in clinical and paraclinical parameters, evaluated on average for 9 months. According to the authors, stem cells are an effective therapy for the treatment of heart failure, improving patient prognosis and ability to exercise.
Acute myocardial infarction (AMI)
The application of stem cells was associated with a significant increase in left ventricular ejection fraction (LVEF) and other variables indicative of improved ventricular function and modification of remodeling in patients with AMI receiving timely percutaneous coronary intervention (PCI) and conventional medication in different studies. Even coronary artery bypass grafting with stem cells offers greater benefits. A number of studies have also shown that intravenous administration could be a more efficient and effective method of treating the heart or coronary arteries than direct application, with logistic, safety, and cost advantages.
Stem cell therapy is evidenced to be a safe way to treat cardiovascular diseases, as it shows an anti-apoptotic effect, reduction of lesion size, improvement of cardiac function through regulation of the immune response, adequate tissue perfusion and activation of growth factors.
We still need to explore a lot of ground, in terms of these and other conditions. You can learn more about regenerative medicine and stem cells by enrolling in our international certification program at www.issca.us
