title: Combinational spinal GAD65 gene delivery and systemic GABA-mimetic treatment for modulation of spasticity.
abstract: BACKGROUND
  Loss of GABA-mediated pre-synaptic inhibition after spinal injury plays a key role in the progressive increase in spinal reflexes and the appearance of spasticity. Clinical studies show that the use of baclofen (GABA(B) receptor agonist), while effective in modulating spasticity is associated with major side effects such as general sedation and progressive tolerance development. The goal of the present study was to assess if a combined therapy composed of spinal segment-specific upregulation of GAD65 (glutamate decarboxylase) gene once combined with systemic treatment with tiagabine (GABA uptake inhibitor) will lead to an antispasticity effect and whether such an effect will only be present in GAD65 gene over-expressing spinal segments.
  
  
  RESULTS
  Adult Sprague-Dawley (SD) rats were exposed to transient spinal ischemia (10 min) to induce muscle spasticity. Animals then received lumbar injection of HIV1-CMV-GAD65 lentivirus (LVs) targeting ventral α-motoneuronal pools. At 2-3 weeks after lentivirus delivery animals were treated systemically with tiagabine (4, 10, 20 or 40 mg/kg or vehicle) and the degree of spasticity response measured. In a separate experiment the expression of GAD65 gene after spinal parenchymal delivery of GAD65-lentivirus in naive minipigs was studied. Spastic SD rats receiving spinal injections of the GAD65 gene and treated with systemic tiagabine showed potent and tiagabine-dose-dependent alleviation of spasticity. Neither treatment alone (i.e., GAD65-LVs injection only or tiagabine treatment only) had any significant antispasticity effect nor had any detectable side effect. Measured antispasticity effect correlated with increase in spinal parenchymal GABA synthesis and was restricted to spinal segments overexpressing GAD65 gene.
  
  
  CONCLUSIONS
  These data show that treatment with orally bioavailable GABA-mimetic drugs if combined with spinal-segment-specific GAD65 gene overexpression can represent a novel and highly effective anti-spasticity treatment which is associated with minimal side effects and is restricted to GAD65-gene over-expressing spinal segments.
authors.affiliation: Neuroregeneration Laboratory, Department of Anesthesiology, University of California San Diego, La Jolla, California, United States of America.
authors.forename: Osamu
authors.initials: O
authors.lastname: Kakinohana
authors.forename: Michael P
authors.initials: MP
authors.lastname: Hefferan
authors.forename: Atsushi
authors.initials: A
authors.lastname: Miyanohara
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Nejime
authors.forename: Silvia
authors.initials: S
authors.lastname: Marsala
authors.forename: Stefan
authors.initials: S
authors.lastname: Juhas
authors.forename: Jana
authors.initials: J
authors.lastname: Juhasova
authors.forename: Jan
authors.initials: J
authors.lastname: Motlik
authors.forename: Karolina
authors.initials: K
authors.lastname: Kucharova
authors.forename: Jan
authors.initials: J
authors.lastname: Strnadel
authors.forename: Oleksandr
authors.initials: O
authors.lastname: Platoshyn
authors.forename: Peter
authors.initials: P
authors.lastname: Lazar
authors.forename: Jan
authors.initials: J
authors.lastname: Galik
authors.forename: Laurent
authors.initials: L
authors.lastname: Vinay
authors.forename: Martin
authors.initials: M
authors.lastname: Marsala
mesh_terms: D000818:Animals; D000927:Anticonvulsants / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use; D002478:Cells, Cultured; D003131:Combined Modality Therapy; D004622:Embryo, Mammalian; D005260:Female; D018755:GABA Agonists / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D005786:Gene Expression Regulation / Q000502:physiology; D015316:Genetic Therapy / Q000379:methods; D005968:Glutamate Decarboxylase / Q000008:administration & dosage / Q000009:adverse effects / Q000235:genetics*; D007278:Injections, Spinal; D008297:Male; D009128:Muscle Spasticity / Q000188:drug therapy / Q000235:genetics / Q000628:therapy*; D018696:Neuroprotective Agents / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use; D009557:Nipecotic Acids / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use; D051381:Rats; D017207:Rats, Sprague-Dawley; D013131:Spine / Q000378:metabolism* / Q000473:pathology; D013552:Swine; D013556:Swine, Miniature; D000078308:Tiagabine
chemical_list: D000927:Anticonvulsants; D018755:GABA Agonists; D018696:Neuroprotective Agents; D009557:Nipecotic Acids; D005968:Glutamate Decarboxylase; C401141:glutamate decarboxylase 2; D000078308:Tiagabine