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Stem-Cell Procedure May Let Teen Live Normally

Times Staff Writer

A Michigan teenager whose heart was accidentally punctured by a nail gun may have hope for a normal life after an experimental stem cell transplant, researchers said Wednesday.

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 as well as 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.

“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.

“It was an unusual circumstance, and we are hoping the procedure will allow recovery,” O’Neill said.

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

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

His heart continued to deteriorate, however, and two days later Timmis performed a balloon angioplasty to open a blocked coronary artery. Even after that procedure, 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. Beginning Feb. 17, they administered the drug 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 then used a process called leukopheresis to filter the stem cells out of Dimitri’s blood over four hours.

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In most of the previous stem cell transplants for heart disease, researchers removed stem cells directly from patients’ bone marrow or muscle tissue. That process, said Dr. Cindy Grines, is extremely painful, requires multiple punctures and the patient must be under general anesthesia. Leukopheresis eliminates those problems and yields more cells, she said.

The cells were infused into his heart in a five-minute procedure on Feb. 21. Researchers hope the stem cells will grow into normal heart cells that will replace the ones damaged.

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


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