One-year chromaffin cell allograft survival in cancer patients with chronic pain: morphological and functional evidence.

The control of chronic pain through transplantation of chromaffin cells has been reported over the past few years. Analgesic effects are principally due to the production of opioid peptides and catecholamines by chromaffin cells. Clinical trials have been reported with allografts consisting of whole-tissue fragments implanted into the subarachnoid space of the lumbar spinal cord (14,19,36). In the present study, allogeneic grafts were successfully used to control chronic pain in two patients over a period of 1 yr based on patient reported pain scores, morphine intake, and CSF levels of Met-enkephalin. Macroscopic examination at autopsy located the transplanted tissue fragments in the form of multilobulated nodules at the level of the spinal axis and cauda equina. Immunocytochemical microscopy showed neuroendocrine cells are positive for chromagranin A (CGA), and enzymes tyrosine hydroxylase (TH) and dopamine-beta-hydroxylase (DbetaH). The results suggest that there is a relationship between analgesic effect, Met-enkephalin levels in CSF, and the presence of chromaffin cells surviving in spinal subarachnoid space.