title: FVIII gene delivery by muscle electroporation corrects murine hemophilia A.
abstract: BACKGROUND
  Hemophilia A treatment relies on costly factor VIII (FVIII) replacement that may transmit iatrogenic viral diseases. Viral vectors and cell implants are being developed as improvements. We investigated in vivo electroporation of naked DNA as a safe and simple method for correcting FVIII deficiency.
  
  
  METHODS
  B-domain-deleted murine FVIII cDNA expression plasmids were constructed with CMV and elongation factor 1alpha promoters for characterisation in murine C2C12 myoblasts. The construct conferring highest in vitro FVIII secretion was electroporated into skeletal muscle of FVII null mice in vivo for phenotypic correction using a protocol that minimised tissue injury.
  
  
  RESULTS
  B-domain-deleted murine FVIII cDNA plasmids induced FVIII secretion from stably transfected C2C12 myoblasts (0.54+/-0.20 mU/day/10(5) cells). Phenotypic correction of hemophilic mice was more consistently achieved using a protocol for in vivo electroporation of gastrocnemius muscle with FVIII cDNA that reduced tissue injury by the use of plate electrodes, hyaluronidase pre-treatment and lower field strength. This technique was associated with <10% muscle necrosis. Activated partial thromboplastin time decreased from 51.4+/-3.3 to 34.7+/-1.1 (mean+/-s.e.m.) seconds (p=0.0004) following in vivo electroporation (0.1 mg plasmid/limb; 8x20 ms pulses, 175 V/cm, 1 Hz) of hemophilic mice. All hemophilic mice (8/8) survived hemostatic challenge after muscle electroporation with FVIII cDNA, whereas all (9/9) untreated hemophilic mice died. Plasmid DNA was detectable only in electroporated muscle and not in all other organs tested, including gonads.
  
  
  CONCLUSIONS
  In vivo intramuscular electroporation of naked FVIII plasmid successfully corrects murine hemophilia.
authors.affiliation: National Cancer Centre, 11 Hospital Drive, Singapore 169610, National University Medical Institute and Department of Biochemistry, National University of Singapore, 10 Kent Ridge Crescent, Republic of Singapore.
authors.forename: Yun Chau
authors.initials: YC
authors.lastname: Long
authors.forename: S
authors.initials: S
authors.lastname: Jaichandran
authors.forename: Liam Pock
authors.initials: LP
authors.lastname: Ho
authors.forename: Sim Leng
authors.initials: SL
authors.lastname: Tien
authors.forename: Soo Yong
authors.initials: SY
authors.lastname: Tan
authors.forename: Oi Lian
authors.initials: OL
authors.lastname: Kon
mesh_terms: D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D017077:Culture Media, Conditioned; D017931:DNA Primers; D018274:Electroporation; D005169:Factor VIII / Q000235:genetics*; D017930:Genes, Reporter; D015316:Genetic Therapy; D006467:Hemophilia A / Q000628:therapy*; D051379:Mice; D018482:Muscle, Skeletal / Q000378:metabolism*; D010641:Phenotype; D010957:Plasmids
chemical_list: D017077:Culture Media, Conditioned; D017931:DNA Primers; D005169:Factor VIII