When cold, sweaty skin and pressure, burning and tightness in the chest strikes, it could just be a sign of a heart attack.
But heart transplants, pacemakers and multiple types of drugs may not be the only solution for fixing permanently damaged heart tissue post-heart attack.
Last week, the scientific journal Stem Cells published a UCLA study about stem cells that may regenerate different kinds of human cardiovascular cells. The article, written by Dr. Robb MacLellan and his colleagues at the David Geffen School of Medicine at UCLA, points to a new type of stem cell that may be used to regenerate heart tissue that dies during a heart attack because of a lack of blood flow.
Induced pluripotent stem cells function like the more commonly used embryonic stem cells, which are currently used in medical research to clone cells from various parts of the human body.
Embryonic stem cells are undifferentiated ““ they are found early enough in human development that they have yet to become liver cells or lung cells, for example.
Those stem cells can thus be used to better understand the ways in which organ systems develop and possible medical conditions that can results from faulty development.
Induced pluripotent stem cells mimic signals similar to embryonic stem cells found in human embryos, said Dr. Martin Pera, the director of the Center for Stem Cell and Regenerative Medicine at the University of Southern California.
“This (research) is an important step forward showing that these cells can do what embryonic stem cells can do,” he said.
But unlike embryonic stem cells, induced pluripotent stem cells do not come from human embryos, and as such can help avoid many ethical issues, he said.
Like embryonic stem cells, these stem cells can be used to regrow organ system-specific tissue following an adverse medical event.
One of the more severe effects of a heart attack is dead heart muscles that cannot be regrown during recovery. Instead, doctors can use induced pluripotent stem cells to replace what is missing by growing cardiac muscle cells and blood vessel cells, Pera said.
So far, studies have only been conducted on mice by transforming mouse skin cells into induced pluripotent stem cells that could eventually be made into multiple types of cardiovascular cells, said Kathrin Plath, an assistant professor of biological chemistry and an author of the study.
But researchers have faced challenges in constructing heart cells from the cardiovascular cells they have cultivated because the engineered cells need to integrate and beat in sequence with the existing heart cells ““ something researchers have been observing heart cells do in petri dishes, Pera said.
Researchers from UCLA, Harvard and Kyoto University in Japan discovered these cells’ potentially unique properties about a year and a half ago, and they are hopeful that these new cells can make the transition from petri dishes to patients, MacLellan said.
Induced pluripotent stem cells are particularly useful when considering the effects of heart transplants on the human immune system.
When patients undergo a heart transplant, their immune system can potentially reject the new heart cells, MacLellan said.
Because transplant tissues may be read as foreign to the patient’s body, patients may have to take drugs that suppress the immune system.
Induced pluripotent stem cells might solve the problem of immune system rejection, since patients would be able to use stem cells from their own bodies, MacLellan said.
But while there are many possibilities of the function of these special cells, there are limitations to bringing them to human testing.
This class of stem cells are created by using retroviruses, harmful viruses that could incorporate themselves and their genetic material into a healthy cell’s DNA.
Scientists have to be careful when injecting induced pluripotent stem cells into subjects, MacLellan said.
While researchers are hopeful they will be able to use those stem cells soon, it may take five to 10 years before scientists can perform tests on human subjects, he said.