Stem cells may help fix heart


A Michigan teen-ager whose heart was accidentally punctured by a nail gun may have hope for a normal life after an experimental stem cell transplant, researchers say.

Dimitri Bonnville, 16, suffered a massive heart attack shortly after cardiac surgeons at Beaumont Hospital in Royal Oak, Mich., repaired the puncture. He was left barely able to breathe and heavily fatigued.

Physicians at the hospital who were preparing to begin a clinical trial of a new cell transplant procedure received approval to perform the innovative technique on him on an emergency basis last month.

"This treatment was Dimitri's only option, aside from a heart transplant," said Dr. William O'Neill. He noted that the boy's parents were not eager to have a transplant because of the lifelong medical care such a procedure would require.

"We're incredibly encouraged that we have already begun to see improvement of heart function," added Dr. Steve Timmis, who performed the cell infusion. Full recovery "would be overly optimistic, but he should be able to live a relatively normal life."

Bonnville was at his part-time job on a construction site Feb. 1 engaging in what he called "horseplay" with his boss's son when the nail gun accidentally fired, piercing his heart. He was taken to Beaumont, where the nail was removed an hour later.

His heart continued to deteriorate, however, and two days later Timmis performed a balloon angioplasty to open a blocked artery. But imaging showed that a major portion of his heart was not pumping and appeared to be dead.

Faced with his continuing decline, the team received permission to perform the experimental procedure. Doctors administered a drug called Neupogen to stimulate production of stem cells - primordial cells in the bone marrow that have the capability to grow into a wide variety of cell types. After four days of treatment, they used a process called leukopheresis to filter stem cells out of Dimitri's blood.

The cells were infused directly into his heart in a five-minute procedure on Feb. 21. The researchers' hope is that the stem cells will grow into normal heart cells that will replace cells damaged in Dimitri's heart attack.

Within five days, the proportion of blood pumped out of Dimitri's heart with each beat increased from 25 percent to 35 percent. Normal is 55 percent. He was discharged from the hospital on Feb. 28. The team is convinced his improvement is due to the stem cells because no improvement was observed after the angioplasty.

At a news conference last week, Dimitri said that his activity was still restricted, but that he was "cautiously optimistic" his condition was improving.

His improvement "should plateau about three months after the treatment," O'Neill said. "This is not by any means a cure, but it does represent a new avenue of treatment."

Thomas H. Maugh II writes for the Los Angeles Times, a Tribune Publishing newspaper.

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