Pain relief by xenograft of subarachnoid microencapsulated bovine chromaffin cells in cancer patients

The bovine chromaffin cells (BCC) implanted into the subarachnoid space can release analgesic substances such as opioid peptides and catecholamines. Clinical trials have provided the evidence that the implantation of polyvinylchloride (PVC) hollow fiber encapsulated BCC by surgery can relief the pain in cancer patients. In the present study, BCC were encapsulated in alginate-polylysine-alginate (APA) microencapsules which protect the grafting of xenogeneic cells from host immune system and allow BCC to function effectively without using immunosuppression agents. The microencapsulated BCCs (5 x 10(6)-8 x 10(6)) were transplanted into the subarachnoid space L3-5 of 17 patients who suffered from chronic cancer pain and had to have long-term administration of analgesics. The pain scores and morphine intake test showed that microencapsulated BCC graft totally stopped the chronic pain in three of the patients over a period of 200 days and in the other three over a period of 100 days. The results suggest that APA microencapsulated UCC xenotransplantation could be a novel alternative approach to managing pain of cancer patients.