title: Comparative study of Chinese hamster ovary cell versus Escherichia coli-derived bone morphogenetic protein-2 using the critical-size supraalveolar peri-implant defect model.
abstract: BACKGROUND
  Chinese hamster ovary (CHO) cell-derived recombinant human bone morphogenetic protein-2 (rhBMP-2) has been introduced for spine, long bone, and craniofacial indications. Escherichia coli- (E. coli) derived rhBMP-2 displays comparable efficacy to CHO cell-derived rhBMP-2 in vitro and in small-animal models. The objective of this study is to evaluate the efficacy of E. coli-derived rhBMP-2 compared to the benchmark CHO cell-derived rhBMP-2 using an established large-animal model.
  
  
  METHODS
  Contralateral, critical-size supraalveolar peri-implant defects in six adult male Hound Labrador mongrel dogs received CHO cell- or E. coli-derived rhBMP-2 (0.2 mg/mL) in an absorbable collagen sponge (ACS) carrier. In each quadrant, three dental implants were placed. A titanium mesh device was used to support space provision. The animals received fluorescent bone markers for qualitative evaluations. Animals were euthanized at 8 weeks for histopathologic and histometric evaluation.
  
  
  RESULTS
  Clinical healing included significant swelling, but none of the animals experienced wound dehiscences. CHO cell- and E. coli-derived rhBMP-2 supported comparable bone formation (new bone area, 35.8 ± 3.6 versus 30.1 ± 2.2 mm(2); bone density, 31.8% ± 1.6% versus 35.6% ± 2.5%; and osseointegration, 32.9% ± 7.4% versus 33.7% ± 8.1%) without statistically significant differences between treatments. Newly formed immature delicate trabecular bone in fibrovascular marrow filled the space underneath the titanium mesh and extended coronally above the mesh. Seroma formation was frequently observed. There were no discernable qualitative histologic differences between treatments.
  
  
  CONCLUSIONS
  CHO cell- and E. coli-derived rhBMP-2 in an ACS carrier appear equally effective at inducing local bone formation in support of dental implant osseointegration.
authors.affiliation: Laboratory for Applied Periodontal & Craniofacial Regeneration, Department of Periodontics, Georgia Regents University College of Dental Medicine, Augusta, GA 30912, USA. jaelee@gru.edu
authors.forename: Jaebum
authors.initials: J
authors.lastname: Lee
authors.forename: Eui Nam
authors.initials: EN
authors.lastname: Lee
authors.forename: James
authors.initials: J
authors.lastname: Yoon
authors.forename: Sung-Min
authors.initials: SM
authors.lastname: Chung
authors.forename: Hari
authors.initials: H
authors.lastname: Prasad
authors.forename: Cristiano
authors.initials: C
authors.lastname: Susin
authors.forename: Ulf M E
authors.initials: UM
authors.lastname: Wikesjö
mesh_terms: D016301:Alveolar Bone Loss / Q000188:drug therapy*; D000539:Alveolar Process / Q000601:surgery; D000818:Animals; D055396:Bone Morphogenetic Protein 2 / Q000008:administration & dosage / Q000494:pharmacology*; D016466:CHO Cells / Q000737:chemistry*; D006224:Cricetinae; D003412:Cricetulus; D015921:Dental Implants; D004285:Dogs; D004926:Escherichia coli / Q000737:chemistry*; D005260:Female; D008297:Male; D023421:Models, Animal; D019647:Oral Surgical Procedures / Q000009:adverse effects; D016348:Osseointegration / Q000187:drug effects*; D011994:Recombinant Proteins / Q000008:administration & dosage / Q000494:pharmacology; D049291:Seroma / Q000209:etiology; D013526:Surgical Mesh; D016212:Transforming Growth Factor beta / Q000008:administration & dosage / Q000494:pharmacology
chemical_list: D055396:Bone Morphogenetic Protein 2; D015921:Dental Implants; D011994:Recombinant Proteins; D016212:Transforming Growth Factor beta; C499469:recombinant human bone morphogenetic protein-2