Retina Cell Therapy for Parkinson’s?

Drug treatment of Parkinson’s disease has shown that dopamine deficiency in certain brain areas is an important mechanism of the disease, as supplying dopamine (by levodopa or bromocriptine, for example) is an effective treatment. Researchers held out hope for the transplant of stem cells that would supply dopamine, but so far progress is not fast: stem cells in sufficient numbers have to be obtained that can be coaxed into producing dopamine, and then transplanted into clinical volunteers.

There seems to have been a short-cut engineered by a company – Titan Pharmaceuticals of San Francisco – who manufacture Spheramine®. This product consists of human retinal pigmented epithelial cells (rHPE) obtained from donated eyes attached to inert gelatin microcarriers. After injection into the putamen area of the brain, these cells provide a constant source of L-dopa. The results after 4 years have been reported at the recent American Association of Neurological Surgeons meeting.

Stereotactic surgery was used to implant over 300,000 rHPE cells in the brains of 6 Parkinson’s patients. Effectiveness, measured by changes in the Unified Parkinson’s Disease Rating Scale, was shown by a dramatic improvement in “on” time and much less “off”’ time. This represented superiority to available medications as well as to fetal-cell transplants, which tend to produce uncontrolled rates of dopamine release. The subjects also reported a 30% increase in self-reported quality-of-life scores at 48 months after the intervention. The study is now being extended to 10-year follow-up exams, and new, larger studies are planned with this technology.

This looks, to my mind, like a fairly large step forward in the treatment of Parkinson’s disease.