title: Synergistic enhancement of collagenous protein synthesis by human gingival fibroblasts exposed to nifedipine and TNF-alpha in vitro.
abstract: BACKGROUND
  Gingival overgrowth occurs in patients receiving nifedipine. Gingival inflammation may be an etiologic factor.
  
  
  METHODS
  Gingival fibroblasts were either exposed to (i) 0-500 ng/ml TNF-alpha or 10(-7) M nifedipine or (ii) 0-500 ng/ml TNF-alpha + 10(-7) M nifedipine for 7 days. 3H-proline was used to quantify collagenous protein synthesis.
  
  
  RESULTS
  Both TNF-alpha and 10(-7) M nifedipine significantly decreased cell proliferation, and 10(-7) M nifedipine + 500 ng/ml TNF-alpha reversed these effects. Collagenous protein synthesis was significantly reduced by TNF-alpha and was significantly enhanced by either 10(-7) M nifedipine or 5-500 ng/ml TNF-alpha + 10(-7) M nifedipine.
  
  
  CONCLUSIONS
  Our data report that nifedipine reverses the primary effects of TNF-alpha on collagenous protein synthesis. Patients with gingivitis could be susceptible to gingival overgrowth during nifedipine therapy as a result of synergistic effects of these agents on fibroblast metabolism, which occurs irrespective of reduced cell numbers.
authors.affiliation: Department of Periodontics, School of Dentistry, University of Mississippi Medical Center, Jackson, Mississippi 39216, USA. rjohnson@sod.umsmed.edu
authors.forename: Roger B
authors.initials: RB
authors.lastname: Johnson
mesh_terms: D000704:Analysis of Variance; D002121:Calcium Channel Blockers / Q000008:administration & dosage / Q000494:pharmacology*; D002452:Cell Count; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D003094:Collagen / Q000096:biosynthesis / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D004357:Drug Synergism; D005109:Extracellular Matrix / Q000187:drug effects; D005347:Fibroblasts / Q000187:drug effects* / Q000378:metabolism; D005881:Gingiva / Q000187:drug effects* / Q000378:metabolism; D006801:Humans; D009543:Nifedipine / Q000008:administration & dosage / Q000494:pharmacology*; D014409:Tumor Necrosis Factor-alpha / Q000008:administration & dosage / Q000494:pharmacology*
chemical_list: D002121:Calcium Channel Blockers; D014409:Tumor Necrosis Factor-alpha; D003094:Collagen; D009543:Nifedipine