Saturday, March 21, 2015

Stem Cells: Plenty of Hope, but Only Halting Progress

English: Diagram to show how embryonic stem ce...
English: Diagram to show how embryonic stem cells are differentiated (Photo credit: Wikipedia)

Edgar Irastorza was just 31 when his heart stopped beating in October 2008.

Mr. Irastorza, a Miami property manager and break dancer, had recently gained weight as his wife’s third pregnancy progressed. “I kind of got pregnant, too,” he said. During a workout one day, he had a heart attack. Minutes later, his pulse flatlined.

He survived the heart attack, but the scar tissue cut his heart’s pumping ability. He couldn’t pick up his children. He couldn’t dance. He fell asleep every night wondering if he would wake up.

Desperation motivated Mr. Irastorza to volunteer to get stem cells injected into his heart. “I just trusted my doctors and the science behind it, and said, ‘This is my only chance,’ “he said.

Over the last five years, by studying stem cells in labs, animals and patients, researchers have brought the vague, grandiose promises of stem cell therapies closer to reality.

Stem cells broke into the public consciousness in the early 1990s, alluring for their potential to help the body beat back diseases of degeneration like Alzheimer’s and to grow new parts to treat conditions like spinal cord injuries.

Progress has been slow. But researchers have been learning how to best use stem cells, what types to use how to deliver them – findings that are not singularly transformational, but progressive and pragmatic.

As many as 4,500 clinical trials involving stem cells are underway in the United States to treat patients with heart disease, blindness, Parkinson’s, H.I.V., diabetes, cancers and spinal cord injuries, among other conditions.

Studies suggest that stem cell therapy can be delivered safely, said Dr. Ellen Feigal of the California Institute of Regenerative Medicine, which has awarded more than $2 billion for stem cell research since 2006.

In addition to continuing safety research, “now what we want to know is: Will it work, and will it be better than what’s already out there?” Dr.Feigal said.

Stem cells harvested from an embryo can turn into any of the body’s 200 cell types. The basic idea of stem cell therapies is simple: Inject them, for example, into a brain whose cells are dying, and replacement cells could grow. The same would hold true muscles, blood and bone.

In theory, stem cells can make repairs, lead to new growth and replace pieces.

But public chatter may imply that stem cell research is further advanced than it is, said Dr. Charles Murry, co-director of the Institute for Stem Cell and Regenerative Medicine at the University of
Washington in Seattle. In fact, very few therapies beyond bone marrow transplants have been shown to be effective, he said.

But stem cells are giving researchers new tools. Using cells created from patients with specific ailments, it is possible to reproduce and study diseases in a lab.

Kevin Eggan of the Harvard Stem Cell Institute uses these advances to study amyotrophic lateral sclerosis, or Lou Gehrig’s disease. Five years ago, he took skin cells from two women dying from the same form of A.L.S. and turned them into stem cells, based on the discoveries of the Japanese researcher Shinya Yamanaka. When he then turned them into nerve cells, he noticed that they were not signaling to one another properly, which was probably causing the neural degeneration that characterizes A.L.S.

He replicated these nerve cells thousands of times and tested drug compounds to see which could correct the signaling problem. He found a candidate that will be tested as early as this year.

Still to be determined is the most cost-effective way to deliver stem cells. Scientists presumed, for instance, that a patient’s heart would repair itself better when injected with its own stem cells. But the study that Mr. Irastorza volunteered for showed that patients fared as well with someone else’s stem cells. If supported by further studies, this means future patients will not need immune suppressants, and that stem cells can be made in large batches-and therefore more cheaply.

Treatment for Mr. Irastorza began with the withdrawing of some of his bone marrow. Researchers took cells believed to be stem cells from the marrow and inserted them into Mr. Irastorza’s heart. It is impossible to know for sure whether the marrow cells’ descendants became heart muscle cells or if repairs were spurred some other way, but today, his doctors say his heart is one-third of the way back to normal.

Natural bone marrow recovery?

Why, then, are there not more success stories? “Progress comes in fits and starts,” said Dr.David Scadden, a co-director of the Harvard Stem Cell Institute, comparing the halting advances in the field to the “war on cancer” declared in 1971.

“No one would say it has fully delivered, but many thousands are alive today because of it and the smaller-scale, very real triumphs along the way. And those triumphs increase with every year, “he said. Using stem cells to routinely treat disease “will take time, but when we look back 20 years from now, I think medicine and human health will be transformed by it.”

Taken from TODAY Saturday Edition, The New York Times International Weekly, September 27, 2014