According to a report published Monday, researchers say that the cells from a patient's own heart can be utilized to regrow new tissue in one's own heart, as well as reverse damage caused by a heart attack.
Scientists from both John Hopkins University in Baltimore and Cedars-Sinai Medical Center in Los Angeles used cells grown from 17 patients to reverse the damage inflicted by their heart attacks. The researchers say that these safe procedures prove that a person's own cells can initiate new heart muscle growth as well as reduce scarring.
When someone experiences a heart attack, that person's heart is left with massive scarring. This scarred heart muscle tissue cannot pump blood as quickly as it did before. Furthermore, other parts of the heart must now help to circulate blood throughout the body, and this process places stress on these other parts of the heart that assist with this process. Since the damaged heart area can't properly conduct electrical currents, abnormal heart rhythms develop, which could potentially cause more heart problems, including heart failure.
Dr. Eduardo Marban, director of the Cedars-Sinai Heart Institute says that this process is the first example of therapeutic regeneration. Marban adds that many spontaneous regenerations of tissues and limbs abound in nature, such as a damaged human liver regrowing to its former full size, or a salamander growing a new tail after it has been severed. He goes on to explain that doctors have not previously been able to initiate therapeutic regeneration in heart patients, but that this could change soon if prolonged patient outcomes – and large-scale clinical trials – validate the results published Monday in the medical journal, The Lancet.
Marban, along with his colleagues, initially presented these findings in November at an American Heart Association conference.
Dr. Peter Johnson, one of the study's authors, said that to gain admittance into this clinical trial, recent heart attack sufferers had to have experienced a considerable amount of damage to their hearts. He also said that participants had to experience lessened squeezing of [blood into the body].
Twenty-five patients participated in this clinical trial held to ascertain the safety of growing cells from one's heart to be injected back into one's heart. Only 17 of these patients actually received the cell transplants, while the remaining eight patients underwent standard post-heart attack treatments.
In this outpatient study, the doctors overseeing the procedure inserted a catheter into each patient's heart, and took out peppercorn-sized pieces of tissue from the healthy portions of the patient's heart. Then, utilizing a procedure invented by Marban, the researchers isolated heart stem cells from the rest of the extracted tissue, and grew millions of new heart cells in a petri dish.
Roughly four to six weeks after the patients experienced the heart attacks, each one had from 12 to 25 million of their own cells derived from their hearts injected back into their hearts.
Marban says that when the initial, first patient's results came back, he and his colleagues were pleased to document that the procedure was safe. After one year, Marban's team reported that just one patient experienced a life-threatening side effect that might have been brought on by the experimental cell transfer.
Six months after the first patient received the treatment derived from the tissue in his own heart, new tissue had regenerated, and the patient experienced significant shrinking of his scar tissue, says Marban, who adds that this is an unprecedented event.
The researchers followed all of the patients for six months, and then continued to monitor 21 of the patients for one year. Half of the patients studied experienced a 50 percent decrease in their scar tissue, and an overall reduction in scar size, says Marban. However, Marban admits that he does not know why these findings occurred.
The amount of new heart tissue grown in the study participants was not small, says Marban, who cites an average of 78 ounces of new heart tissue found in each patient. He says these findings are quite extraordinary, since the section of the heart that pumps bloods is about 5.3 ounces.
Patients in the study that did not receive the heart cell transplants did not experience new tissue growth and their scarring remained exactly the same.
The deputy director of the NIH's National Heart, Lung, and Blood Institute's Division of Cardiovascular Sciences, Sonia Skarlatos, Ph.D., says this preliminary research is an exciting move forward. However, she says that much more research of this type needs to be performed on a lot more patients who should be monitored for longer periods than reported in the first study. She does admit that she is hopeful that the follow-up study's reports will confirm this first study's positive results.
Skarlatos says that through the prevention of heart attacks, you might prevent heart failure that occurs in many of these post-heart attack patients. She did not participate in the research, yet the National Heart, Lung and Blood Institute did fund the study.
Skarlatos adds that it is still unclear why the scar tissue disappeared and the heart tissue regenerated. Did the cells, the cell proteins or another factor contribute to these occurrences? Only further research will tell, she says.
We did witness a flash of hope during animal testing of this nature. However, human testing yielded much better results, says Marban, who adds that it usually does not transpire this way in medical research.