Neurotrophic factor-secreting cell grafting for cerebral ischemia: preliminary report

In this experiment, we examined a possible protective effect of encapsulated neurotrophic factor-secreting cell grafting for ischemic injury. We established a basic fibroblast growth factor (bFGF)-secreting cell line by genetic manipulation. We enveloped these cells into polymer capsules, which consist of a semipermeable membrane, and implanted them into the right striatum of rats. At 6 days after implantation, these rats received right middle cerebral artery occlusion (MCAO) using interluminal suture technique. At 24 h after MCAO, rats were sacrificed and their cerebral infarction volume was determined by 2,3,5-triphenyltetrazolium chloride (TTC) staining and image analysis. We found approximately 30% reduction in infarct volume in the encapsulated bFGF-secreting cell grafting groups vs. the encapsulated naive BHK cell grafting group or the without implantation group. We measured bFGF secretion from encapsulated bFGF-secreting cells using enzyme-linked immunosorbent assay (ELISA). The retrieved capsules continued to secrete bFGF. There was no significant difference of bFGF secretion between the capsules before and after transplantation. A large number of viable BHK-bFGF cells was observed within the full length of the retrieved capsule. These results indicate that encapsulated bFGF-secreting cell grafting exerts a protective effect on ischemic injury.