Stem cells can bring heart back to normal after attack

Stem cells can bring heart back to normal after attack

A heart attack takes place when blood vessels that supply blood to the heart are blocked, preventing enough oxygen from getting to the organ. The heart muscle dies or becomes permanently damaged, tissue is scarred and the heart becomes enlarged. Now for survivors of cardiac arrest, stem cell injections afterwards can help enlarged hearts recover in size and function.

Joshua M. Hare, MD, of the University of Miami, and colleagues reviewed the treatment of eight patients at an average of 5.7 years after myocardial infarction (MI) didn't show significant ejection fraction gains, but the improvements in cardiac chamber dimensions and contractility persisted through the end of one year of follow-up.

Function of the heart muscle in the treated region showed signs of improvement by three months. The infarct region, or area of tissue damage, dropped 18.3% in size by one year after stem cell injections.

By 12 months after the injections, regional contractility as measured by peak eulerian circumferential strain had returned to the level of the border zone around the infarct. Reverse remodeling in left ventricular chamber dimensions took longer, gaining significance only at six months post-treatment.

The study's authors state:

"A therapy that leads to reverse remodeling in chronically scarred human hearts would be precedent setting and predicted to have favorable clinical benefits for patients."

Prior studies have tried a variety of stem cell types for treating old and new myocardial infarctions with some success, although further confirmation is needed in larger controlled trials. The group cautioned about a lack of statistical power because of the study's small size, lack of placebo comparison, and that only four patients had longitudinal assessment of scar size.

Dr. Hare continues:

"The reverse remodeling caused substantial parallel declines in systolic and diastolic volumes, so that an ejection fraction increase was obscured. This strongly suggests that ejection fraction is not a good primary endpoint for assessing responses to cell therapy in dilated hearts, and that chamber size, MI size, or regional functions are more likely to reflect a favorable outcome."

Stem cell research began with a goal of being able to cure persons based on their own unique genetic make-up and healing inefficiencies by using harvested cells. There are enormous scientific challenges, but the most debated points of discussion, government intervention and personal doubt, come from intense ethical inclusions such as privacy, consent and at times the withdrawal of that consent to use embryos for example in this evolving treatment application.

Stem cells have a unique feature in that they can be coaxed into developing into some or all of the 220 cell types found in the human body. Of the three types of stem cells, embryonic stem cells have the greatest potential in that they can theoretically become any of the 220 cell types. Adult stem cells are less useful in that they have already started to specialize and can only become one of a few cell types. Induced pluripotent stem cells are specially treated cells that can be processed to behave somewhat like embryonic stem cells.

Hematopoietic stem cells (HSCs), used in this research, are multipotent stem cells that give rise to all the blood cell types including myeloid (monocytes and macrophages, neutrophils, basophils, eosinophils, erythrocytes, megakaryocytes/platelets, dendritic cells), and lymphoid lineages (T-cells, B-cells, NK-cells).

HSCs are found in the bone marrow of adults, which includes femurs, hip, ribs, sternum, and other bones. Cells can be obtained directly by removal from the hip using a needle and syringe, or from the blood following pre-treatment. Other sources for clinical and scientific use include umbilical cord blood, placenta and mobilized peripheral blood.

Source: The American Heart Association Circulation Research

One Year After Heart Regeneration Therapy with Cardiac Stem Cells Long Term Results (Video Medical And Professional 2020).

Section Issues On Medicine: Cardiology