Stem cells in heart attack: the more, the better
As part of PreSERVE-AMI, one of the largest randomized clinical trials of cell therapy for myocardial infarction in the United States, doctors from 60 clinics injected their own stem cells isolated from bone marrow into the heart tissue of 161 patients. The purpose of this was to increase the efficiency of recovery of the affected myocardial infarction.
All participants received standard therapy – the introduction of a stent – and were included in the study only if, 4 days after myocardial infarction and stenting, their ejection fraction (a measure of the assessment of the contractility of the heart) was less than 48% of the norm. The average value of the ejection fraction at the beginning of the study was 34%, which indicated serious myocardial damage.
After inclusion in the study, bone marrow puncture was taken from patients, the stem cells contained in which were isolated and injected into the coronary artery. The dose of injected cells varied from 10 to 40 million. Patients of the control group, randomly selected, were injected with a placebo.
In several earlier studies, patients with myocardial infarction were injected with unsorted bone marrow cells. During this study, bone marrow samples were sent to the NeoStem laboratory, where the most valuable fraction of stem cells expressing the CD34 marker was isolated from them and sent back to the clinic for administration to the patient.
The degree of recovery and results were assessed using several criteria: MACE (from the English Major Adverse Cardiovascular Event – major acute cardiac complications), ranging from hospitalization for pain in the heart to death, ejection fraction, assessed using magnetic resonance imaging, and perfusion or blood flow to the heart, assessed using the method of gamma tomography. Cardiac tomography was performed 6 months after the therapy, and the main acute cardiac complications were recorded on average during 12 months of follow-up.
Protocol of the PreSERVE-AMI clinical trial.
Major acute cardiac complications occurred in 14% of patients in the control group (n = 83), in 17% of patients who received an injection of less than 14 million cells (n = 47), in 10% of patients who were injected with more than 14 million cells (n = 31; including the next group), and in 7% of patients who were injected with more than 20 million cells (n = 15). Mortality was 3.6% for the control group and 0% in the entire experimental group.
A similar dose-dependent trend was demonstrated by a change in the ejection fraction, which increased by 4.9% in the control group, by 3.1% in the group that received injections of less than 14 million cells, by 5.8% in the group that received injections of more than 14 million cells, and by 10.2% in the group that received the maximum dosages of cells. The images obtained by gamma tomography did not demonstrate a significant effect on improving blood flow in the heart.
As a result of a random effect that occurred during randomization of study participants, patients who underwent experimental therapy were initially at a disadvantage in terms of prospects for myocardial recovery, as they underwent stenting with a delay compared to patients in the control group (on average 931 compared to 569 minutes).
In general, the researchers concluded that the maximum effect of therapy was received by patients who were injected with the maximum number of CD34+ cells. According to the head of the study, Professor Arshed Quyyumi from Emory University, additional monitoring of the condition of patients should further clarify the effect of stem cell administration on the results of recovery after myocardial infarction.
At the same time, NeoStem specialists note that during the study they were able to standardize procedures in such a way that in the future each patient will be able to receive an injection of more than 20 million CD34+ cells.
The results of the clinical trial were presented on November 17 at the Congress of the American Heart Association, held on November 15-19 in Chicago.
Evgeniya Ryabtseva
Portal "Eternal youth" http://vechnayamolodost.ru based on the materials of Emory Health Sciences:
In landmark study of cell therapy for heart attack, more cells make a difference.
26.11.2014