CELL THERAPY WITH ENCAPSULATED XENOGENEIC TUMOR-CELLS SECRETING BETA-ENDORPHIN FOR TREATMENT OF PERIPHERAL PAIN

The purpose of this study was to assess whether xenogeneic tumor cells secreting beta-endorphin and immunologically isolated in polymer caps ules could survive and continue to reduce pain when transplanted into the spinal cerebro-spinal fluid (CSF) space of rats, Also, a silicone container for polymer capsules was designed for the clinical applicati on of this method of cell therapy, The mouse tumor cell lines, proopio melanocortin gene transfected Neuro2A which secrete beta-endorphin, we re enclosed in polymer capsules at a density of 5 x 10(6)/mL, and tran splanted into the spinal CSF space from the occipito-atlantal junction of male Sprague-Dawley rats. Three analgesiometric tests - the tail p inch test, the hot plate test, and electrical stimulation test showed that the rats with encapsulated Neuro2A (n = 6) were significantly les s sensitive to pain after transplantation than control animals (n = 8) , The analgesia induced by the encapsulated cells secreting beta-endor phin was attenuated by the opiate antagonist naloxone, Morphological s tudy revealed that the encapsulated cells survived for 1 mo after tran splantation into the CSF space, An in vitro experiment on cultured cap sules (3 cm long) with a silicone container (Kaneka Medics Co) showed that the encapsulated Neuro2A (5 x 10(6) mt) could secrete peptides fo r 1 mo. The results of this study indicate that immunologically isolat ed xenogeneic tumor cells can secrete opiate in the CSF space, and tha t a silicone container may help the application of this method to the treatment of cancer pain.