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

A Miami property manager, break-dancer and former high school wrestler, Irastorza 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 felt short of breath and insisted that friends rush him to the hospital. Minutes later, his pulse flatlined.

He survived the heart attack, but the scar tissue that resulted cut his heart's pumping ability by a third. He couldn't pick up his children. He couldn't dance. He fell asleep every night wondering if he would wake up in the morning.

Desperation motivated Irastorza to volunteer for a highly unusual medical research trial: getting stem cells injected directly into his heart.

"I just trusted my doctors and the science behind it, and said, 'This is my only chance,'" he said recently.

Over the past five years, by studying stem cells in lab dishes, test animals and intrepid patients like Irastorza, 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. The Michael J. Fox Foundation for Parkinson's Research, an early supporter of stem cell research, pulled its financial backing two years ago, saying that it preferred to invest in research that was closer to providing immediate help for Parkinson's disease patients.

But researchers have been slowly learning how to best use stem cells, what types to use and how to deliver them to the body - findings that are not singularly transformational, but progressive and pragmatic.

See more here:

Trials and tribulations of stem cell therapy