title: Effect of nicotine-treated epithelial cells on the proliferation and collagen production of gingival fibroblasts.
abstract: OBJECTIVE
  Several in vitro and in vivo studies have indicated that tobacco smoking may be an important risk factor for the development and severity of inflammatory periodontal disease.
  
  
  METHODS
  In the present study, we developed an in vitro model to study the interactions between nicotine-treated epithelial cells (EC) and gingival fibroblasts (GF) derived from the same patient. EC were treated with nicotine concentrations varying from 1 microg/ml to 500 microg/ml and their effect on different functions of GF was studied. The proliferation of GF was evaluated by the incorporation of 3H-thymidine. A dose-dependent inhibition was observed with nicotine concentrations > or =100 microg/ml. Similar results were observed when studying the total protein synthesis of GF by incorporation of 3H-proline into non-dialyzable material.
  
  
  RESULTS
  When collagen production was evaluated by 3H-proline incorporation into collagenase-sensitive protein, a dose-dependent reduction was observed: the degree of inhibition varied from 25% with 50 microg/ml nicotine, to almost 60% with 500 microg/ml. Interestingly, the production of non-collagenous proteins decreased by almost 50% only when EC were treated with the highest concentration of nicotine.
  
  
  CONCLUSIONS
  The results suggest that epithelial cells, acting as mechanical barrier, can reduce but not completely eliminate the deleterious effect of nicotine on gingival fibroblasts.
authors.affiliation: Division of Physiopathology and Periodontology, School of Dentistry, Medical Faculty, University of Geneva, 19 rue Barthelemy-Menn, 1205 Geneva, Switzerland.
authors.forename: C
authors.initials: C
authors.lastname: Giannopoulou
authors.forename: N
authors.initials: N
authors.lastname: Roehrich
authors.forename: A
authors.initials: A
authors.lastname: Mombelli
mesh_terms: D002455:Cell Division / Q000187:drug effects; D003094:Collagen / Q000096:biosynthesis*; D004847:Epithelial Cells / Q000187:drug effects*; D005260:Female; D005347:Fibroblasts / Q000187:drug effects* / Q000378:metabolism*; D005881:Gingiva; D006801:Humans; D066298:In Vitro Techniques; D008297:Male; D009538:Nicotine / Q000009:adverse effects*; D018722:Nicotinic Agonists / Q000009:adverse effects*; D010510:Periodontal Diseases / Q000209:etiology; D012307:Risk Factors
chemical_list: D018722:Nicotinic Agonists; D009538:Nicotine; D003094:Collagen