Transplantation of embryonic porcine mesencephalic tissue in patients with PD

Objective: To assess the safety and the effect on standardized clinical rating measures of transplanted embyronic porcine ventral mesencephalic (VM) tissue in advanced PD, Methods: Twelve patients with idiopathic PD underwent unilateral implantation of embryonic porcine VM tissue; six received cyclosporine immunosuppression and six received tissue treated with a monoclonal antibody directed against major histocompatibility complex class I. Patients were followed for 12 months and assessed by clinical examination, MRI, and F-18-levodopa PET. Porcine endogenous retrovirus testing was conducted by PCR-based method an peripheral blood mononuclear cells. Results:Cell implantation occurred without serious adverse events in all patients. Cultures were negative for bacterial and unknown viral contamination. No porcine endogenous retrovirus DNA sequences were found. MRI demonstrated cannula tracts within the putamen and caudate, with minimal or no edema and no mass effect at the transplant sites. In the medication-off state, total Unified Parkinson's Disease Rating Scale scores improved 19% (p = 0.01). Three patients improved over 30%. There were two patients with improved gait. F-18-levodopa PET failed to show changes on the transplanted side. Conclusions: Unilateral transplantation of porcine embryonic VM cells into PD patients was well tolerated with no evidence of transmission of porcine endogenous retrovirus. Changes in standardized clinical go rating measures were variable, similar to the results of the first trials of unilateral human embryonic allografts that transplanted small amounts of tissue.