Grafts of immortalized chromaffin cells bio-engineered to improve met-enkephalin release also reduce formalin-evoked c-fos expression in rat spinal cord.
Transplantation of adrenal medullary tissue for terminal cancer pain has been tested clinically, but this approach is not practical for routine use because of the shortage of organ donors and lack of tissue homogeneity. As a first alternative step, we have generated immortalized chromaffin cells over-expressing opioid peptides, namely met-enkephalin. Rat chromaffin cells have been genetically modified with vectors containing expression cassettes with either synthetic met-enkephalin or pro-enkephalin gene coding regions, fused with the nerve growth factor signal peptide for secretion. After stable transfection and differentiation in vitro, met-enkephalin and pro-enkephalin cells had higher met-enkephalin immunoreactivity and secreted met-enkephalin levels, compared to control cells containing the expression vector only. In the formalin hindpaw-injection model, 15 days after subarachnoid transplant of cells, grafts of met-enkephalin and pro-enkephalin cells significantly reduced the number of formalin-evoked c-fos immunoreactive spinal neurons in the spinal cord, compared to grafts of vector-alone chromaffin cells. The use of such expandable cell lines, for chronic spinal delivery of opiates, could offer an attractive and safe alternative strategy based on ex vivo gene therapy for the control of opioid-sensitive chronic pain.
Laboratoire Douleur et Therapie cellulaire, Faculte de Medecine Rangueil, 133 route de Narbonne, 31077 Toulouse, France.
H
H
Duplan
R Y
RY
Li
C
C
Vue
H
H
Zhou
L
L
Emorine
J P
JP
Herman
M
M
Tafani
Y
Y
Lazorthes
M J
MJ
Eaton
D000704:Analysis of Variance; D000818:Animals; D002452:Cell Count / Q000379:methods; D002461:Cell Line, Transformed; D019439:Chromaffin Cells / Q000378:metabolism / Q000502:physiology / Q000637:transplantation*; D004744:Enkephalin, Methionine / Q000235:genetics / Q000378:metabolism*; D005557:Formaldehyde / Q000494:pharmacology*; D005786:Gene Expression Regulation / Q000187:drug effects; D005818:Genetic Engineering; D006085:Graft Survival / Q000502:physiology; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods; D008297:Male; D020932:Nerve Growth Factor / Q000235:genetics / Q000378:metabolism; D010146:Pain / Q000139:chemically induced / Q000378:metabolism*; D010625:Phenylethanolamine N-Methyltransferase / Q000378:metabolism; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism*; D012333:RNA, Messenger / Q000096:biosynthesis; D011863:Radioimmunoassay / Q000379:methods; D051381:Rats; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D013116:Spinal Cord / Q000187:drug effects / Q000378:metabolism*; D014162:Transfection / Q000379:methods
D016760:Proto-Oncogene Proteins c-fos; D012333:RNA, Messenger; D005557:Formaldehyde; D004744:Enkephalin, Methionine; D020932:Nerve Growth Factor; D010625:Phenylethanolamine N-Methyltransferase