Stem cells provide increased quality treatment for microvascular dysfunction

The results of a study conducted in the United States showed the effectiveness of stem cell therapy in patients with angina caused by coronary microvascular dysfunction (CMD).

CMD is a disease characterized by impaired functioning of small blood vessels that feed the heart muscle. Coronary microvascular dysfunction leads to ischemia, angina and adverse outcomes in patients with non-obstructive coronary artery disease (NOCAD). Women are most prone to this disease.

Patients are experiencing a significant deterioration in the quality of life, and, unfortunately, there is no specific therapy for them today. Treatment with CD34+ stem cells dilates the blood vessels of the microvasculature, improves general condition, exercise tolerance and reduces mortality in preclinical models in patients with refractory angina, critical limb ischemia and dilated cardiomyopathy.

CD34+ stem cells are endothelial progenitor cells shown in preclinical models to be effective in improving microvascular angiogenesis (the formation of new blood vessels) in ischemic tissues. Clinical studies of refractory angina, critical limb ischemia and dilated cardiomyopathy have shown therapeutic efficacy, including reducing the frequency of angina attacks, improving exercise performance, reducing mortality and the need for amputations.

A group of scientists tested CD34+ autologous stem cell therapy in 20 NOCAD patients with persistent angina and invasive coronary flow reserve (CFR) ≤2.5. Evaluation results included the frequency of angina attacks, classification of angina based on its severity (according to the Canadian Cardiovascular Society, CCS), Seattle Angina Questionnaire (SAQ), modified Bruce exercise treadmill test (ETT), and labs.

Subjects received granulocyte colony stimulating factor (G-CSF) 5 μg/kg/day for five days before leukapheresis followed by the generation of CD34+ stem cells for collection. Cells were introduced by a single infusion into the LAD coronary artery. A six-month evaluation included an invasive CFR, the frequency of angina attacks, CCS, SAQ, and ETT.

CFR significantly increased from 2.08 +/-0.3 in the initial state to 2.68 +/-0.8 six months after a single infusion of CD34+ cells, and the researchers reported that they did not observe any side effects associated with stem cells.

«This was a proof of concept trial to evaluate the safety and efficacy of CD34+ stem cells administered via intracoronary infusion for CMD patients with abnormal coronary flow reserve <2.5», – said Timothy D. Henry, MD, lead author of the study and Society for Cardiovascular Angiography and Interventions (SCAI) vice president. «Our results demonstrate a significant improvement in coronary flow reserve with a single intracoronary infusion of CD34+ cells as well as a significant improvement in angina and quality of life».

The results were presented in the form of full-fledged clinical trials at the SCAI 2020 virtual conference.

The authors concluded that CD34+ stem cell therapy is promising for patients with CMD suffering from angina and non-obstructive coronary artery disease. A prospective randomized clinical trial is forthcoming.