Skin cells reprogrammed to produce dopamine that were inserted into the brain of a man with Parkinson’s disease have allowed him to tie his shoes again and resume swimming and biking, researchers report.

The experimental treatment, initiated two years ago and financed partly by the patient, used the 69-year-old’s own skin cells to create dopamine-releasing nerve cells.

Use of autologous cells derived from fibroblasts obtained by skin biopsy was expected to lower the need for immunosuppression, the authors write in the New England Journal of Medicine.

Researchers say the transformed skin cells, transplanted into the putamens of both hemispheres of the brain in surgical procedures six months apart, continued to produce the dopamine needed to ease the Parkinson’s symptoms.