title: Optimization of immunosuppressive therapy for spinal grafting of human spinal stem cells in a rat model of ALS.
abstract: Previous rodent studies employing monotherapy or combined immunosuppressive regimens have demonstrated a variable degree of spinal xenograft survival in several spinal neurodegenerative models including spinal ischemia, trauma, or amyotrophic lateral sclerosis (ALS). Accordingly, the  characterization of optimal immunosuppressive protocols for the specific neurodegenerative model is critical to ensure reliable assessment of potential long-term therapeutic effects associated with cell replacement. In the present study we characterized the survival of human spinal stem cells  when grafted into the lumbar spinal cords of a rodent model of ALS, SOD1 (G93A) male and female rats (60-67 days old). Four different immunosuppressive protocols were studied: i) FK506 (q12h); ii) FK506 (qd) + mycophenolate (PO; q12h, up to 7 days postop); iii) FK506 (qd) + mycophenolate  (IP; q12h, up to 7 days postop); and iv) FK506 (qd) + mycophenolate (IP; qd, up to 7 days postop). Three weeks after cell grafting the number of surviving human cells was then systematically assessed. The highest density of grafted cells was seen in animals treated with FK506 (qd) and mycophenolate  (IP; qd; an average 915 ± 95 grafted cells per spinal cord section). The majority of hNUMA-positive cells colocalized with doublecortin (DCX) immunoreactivity. DCX-positive neurons showed extensive axodendritic sprouting toward surrounding host neurons. In addition, migrating grafted  cells were identified up to 500 μm from the graft. In animals treated with FK506 (q12h), FK506 (qd) + mycophenolate (PO; q12h) or FK506 (qd) + mycophenolate (IP; q12h), 11.8 ± 3.4%, 61.2 ± 7.8%, and 99.4 ± 8.9% [expressed as percent of the FK506 (qd) and mycophenolate  (IP; qd)] cell survival was seen, respectively. In contrast to animals treated with a combination of FK506 + mycophenolate, robust CD4/8 immunoreactivity was identified in the vicinity of the injection tract in animals treated with FK506 only. These data suggest that a combined, systemically  delivered immunosuppression regimen including FK506 and mycophenolate can significantly improve survival of human spinal stem cells after intraspinal transplantation in SOD1 (G93A) rats.
authors.affiliation: Neuroregeneration Laboratory, Department of Anesthesiology, University of California-San Diego, La Jolla, CA 92093-0695, USA. mhefferan@ucsd.edu
authors.forename: Michael P
authors.initials: MP
authors.lastname: Hefferan
authors.forename: Karl
authors.initials: K
authors.lastname: Johe
authors.forename: Thomas
authors.initials: T
authors.lastname: Hazel
authors.forename: Eva L
authors.initials: EL
authors.lastname: Feldman
authors.forename: J Simon
authors.initials: JS
authors.lastname: Lunn
authors.forename: Martin
authors.initials: M
authors.lastname: Marsala
mesh_terms: D000690:Amyotrophic Lateral Sclerosis / Q000188:drug therapy / Q000276:immunology / Q000628:therapy*; D000818:Animals; D002470:Cell Survival / Q000187:drug effects; D004195:Disease Models, Animal; D000089622:Doublecortin Domain Proteins; D000089662:Doublecortin Protein; D005260:Female; D005455:Fluorescent Antibody Technique; D006801:Humans; D007108:Immune Tolerance / Q000187:drug effects; D007165:Immunosuppression Therapy / Q000379:methods*; D007166:Immunosuppressive Agents / Q000627:therapeutic use*; D008297:Male; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D009479:Neuropeptides / Q000378:metabolism; D051381:Rats; D013116:Spinal Cord / Q000166:cytology*; D033581:Stem Cell Transplantation; D013234:Stem Cells / Q000166:cytology*; D013601:T-Lymphocytes / Q000187:drug effects / Q000378:metabolism; D016559:Tacrolimus / Q000494:pharmacology / Q000627:therapeutic use
chemical_list: C000714328:DCX protein, human; C000714848:Dcx protein, rat; D000089622:Doublecortin Domain Proteins; D000089662:Doublecortin Protein; D007166:Immunosuppressive Agents; D008869:Microtubule-Associated Proteins; D009479:Neuropeptides; D016559:Tacrolimus