title: Cultured human chromaffin cells grafted in spinal subarachnoid space relieves allodynia in a pain rat model.
abstract: BACKGROUND
  Implantation of xenogenic chromaffin cells into the spinal subarachnoid space can produce analgesia in neuropathic pain models. However, transplantation of xenogeneic chromaffin cell has a potential risk of viral or bacterial infections from animals to humans including encephalopathy due to prion transmission. The aim of this study was to investigate the possibility of developing a homogeneic source of therapeutic chromaffin cells.
  
  
  METHODS
  Anti-allodynic effects of human chromaffin cells (HCCs) were evaluated in a neuropathic pain model in rats induced by chronic constriction injury of the sciatic nerve. HCCs encapsulated with alginate-poly-L-lysine-alginate were intrathecally implanted into rats (n = 10), while empty capsules were intrathecally implanted as a control (n = 8). Levels of norepinephrine from encapsulated HCCs before and after nicotinic stimulation were measured. We then perfomed a behavior test (cold allodynia) with acetone. In addition, to assess the potential contribution to pain reduction of opioid peptides released from the HCCs, all animals were injected with naloxone.
  
  
  RESULTS
  The concentration of norepinephrine after nicotine stimulation was significantly increased compared to basal levels. Intrathecal implantation of encapsulated HCCs, significantly reduced cold allodynia as compared to rats receiving empty capsules (P < 0.05). Fifteen minutes after the injection of naloxone, cold allodynia significantly decreased in rats with HCCs (P < 0.05), while the degree of cold allodynia in control animals was unaltered.
  
  
  CONCLUSIONS
  From these results, it appears that HCCs have a possibility as an analgesic source for transplants delivering pain-reducing neuroactive substances.
authors.affiliation: Department of Anesthesiology and Pain Medicine, Kyungpook National University School of Dentistry, Daegu, Korea.
authors.forename: Younghoon
authors.initials: Y
authors.lastname: Jeon
authors.forename: Woon Yi
authors.initials: WY
authors.lastname: Baek
authors.forename: Seung Hyun
authors.initials: SH
authors.lastname: Chung
authors.forename: Nari
authors.initials: N
authors.lastname: Shin
authors.forename: Hye Rim
authors.initials: HR
authors.lastname: Kim
authors.forename: Soon Ae
authors.initials: SA
authors.lastname: Lee