In Vivo Evaluation of the Potential Role of Anti-Inflammatory Factors Involved in the Survival and Mechanism of Action of hRPE-Cell Implants for Parkinson's Disease
Parkinson’s disease is a neurodegenerative disorder that causes tremors, muscular rigidity, slowness of movement and postural instability. Affecting up to three per cent of the elderly population, Parkinson’s is characterized by depletion of the neurotransmitter dopamine and chronic inflammation in the substantia nigra region of the brain. While various pharmacological treatments alleviate symptoms of the disease, these medications eventually lose effectiveness and cause debilitating side effects. Cell-based transplantation therapies are being studied as alternative treatment options for Parkinson’s disease, but the routine use of these therapies has been delayed by mixed clinical results, safety and logistical concerns, and ethical issues. Recently, human retinal pigment epithelial (hRPE) cells have been proposed as a tissue transplant alternative for Parkinson’s disease and are currently being used in Phase II clinical trials. Found in the inner retina, hRPE cells are easily grown in culture so that a single donor can provide sufficient tissue for multiple recipients. Several studies have shown sustained reversal of Parkinsonian symptoms after hRPE implants with minimal side effects. Especially interesting is early evidence suggesting that transplanted cells may have the potential for long-term survival without requiring immunosuppressive drugs. However, little is known about the mechanisms of action of hRPE cells. Joseph Flores is researching the survival of implanted hRPE cells and the ability of implanted hRPE cells to replace depleted dopamine and induce a long-term anti-inflammatory response. A better understanding of hRPE-cell implants may lead to its routine use as a therapeutic alternative for Parkinson’s disease and improved outcomes for patients.