In heart diseases, time only makes a physical injury worse. If starved for oxygen, heart cells die, their places filled not by fresh replacements but by scarring. Burdened with useless tissue, the heart needs to work harder to pump the blood. The overworked heart gets bigger and it can never catch up with its old pace. Despite doctors’ efforts to save them with drugs, catheters, stents and surgery, 5 million Americans currently suffer from heart failure. So cardiologists have started shoring up the dying hearts with stem cells, immature cells that can be coaxed into transforming into many different types. In spite of the encouraging results of the experimental surgeries, noone knows how the treatment works.
How the stem cells renew the tissue or the side-effects, are unkown. There are many experiments done on this issue: 1)mice who -deliberately caused to- suffer heart attack, cured by transmission of bone marrow rich in stem cells. 2)In Gremany, the hearts of 60 patients, who suffered heart diseases, were transmitted bone marrows by catheters; their hearts pumped more blood, strongly. 3)In Pittsburgh University, 100 patients’ hearts pumped more blood after stem cell treatment, without any side-effects. 4)In Equador Republic, 10 patients with were ejected stem cells obtained from the fetus.
In a month, it was absorbed that the exhausted patients were suddenly revived, their hearts started to pump blood in rate %40 higher than before. However, in the experiment of France, 10 patients were treated with the stem cells taken from the leg muscles. The hearts of four of them unexpectedly started beating dangerously off tempo. The rhythm disorder is common in treatments of this source. The possible sources of stem cells are, bone marrows, cells form the front skeletal muscles, the own heart of the patient, and the most controversial- embryos. Although the required scientific datum is not enough, the supporters of this treatment argue the probabilities about the way the stem cells work; the cells don’t have to become muscle to give the heart another chance. they may reinvigorate old cells, act as beacons for growth factors or serve as midwives to the birth of new blood vessels.
In Turkey, approximately half of the deaths are caused by heart-vessel diseases, which is four times the number of deaths caused by cancer.”(2) We know that the heart diseases are urgent issues that need to be taken care of, “for critics, that means the risks outweigh the benefits. The treatment’s supporters counter that the sickest patients will gladly accept those risks rather than face certain death.”(1) One of the risks of this treatment was the arrhythmias caused by the source of the stem cells.
“The Hopkins group was able to minimize arrhythmias dramatically by using gene therapy to replace a key protein, called connexin 43, missing in heart muscle fibers that regrew as a result of the stem cell injections. Connexin 43 makes up the gap junctions between muscle cells, allowing cells to communicate with each other to regularly contract and expand…In the gene therapy experiments, the Hopkins team increased production of connexin 43 by injecting a virus carrying the gene that codes for the gap-junction protein into the cultured cells. The researchers found that the addition of connexin 43 dramatically increased conductivity between cells to normal levels, with only two of nine cultures developing signs of arrhythmia.”(3)
All these strategies, rely on using stem cells from the patients themselves. There’s a flaw with that approach, though: older patients’ stem cells are not as robust and active as younger patients’, but it’s often the older patients who need the treatment the most. Douglas Losordo form St. Elizabeth’s Medical Center, “wants to combine his stem-cell procedure with gene therapy, removing the cells from the bone marrow, modifying them and then putting them back in.”(1)
Scientists suggest that, heart cells grown from embryos could mesh with mature heart tissue and regulate its beat. They might someday replace mechanical pacemakers, meaning stem-cell treatment could benefit not just heart-failure sufferers but also an entirely new category of patients. The thought of this encouraging future of the treatment, makes many doctors, and patients-take heart.