title: Bacterial lysine decarboxylase influences human dental biofilm lysine content, biofilm accumulation, and subclinical gingival inflammation.
abstract: BACKGROUND
  Dental biofilms contain a protein that inhibits mammalian cell growth, possibly lysine decarboxylase from Eikenella corrodens. This enzyme decarboxylates lysine, an essential amino acid for dentally attached cell turnover in gingival sulci. Lysine depletion may stop this turnover, impairing the barrier to bacterial compounds. The aims of this study are to determine biofilm lysine and cadaverine contents before oral hygiene restriction (OHR) and their association with plaque index (PI) and gingival crevicular fluid (GCF) after OHR for 1 week.
  
  
  METHODS
  Laser-induced fluorescence after capillary electrophoresis was used to determine lysine and cadaverine contents in dental biofilm, tongue biofilm, and saliva before OHR and in dental biofilm after OHR.
  
  
  RESULTS
  Before OHR, lysine and cadaverine contents of dental biofilm were similar and 10-fold greater than in saliva or tongue biofilm. After 1 week of OHR, the biofilm content of cadaverine increased and that of lysine decreased, consistent with greater biofilm lysine decarboxylase activity. Regression indicated that PI and GCF exudation were positively related to biofilm lysine after OHR, unless biofilm lysine exceeded the minimal blood plasma content, in which case PI was further increased but GCF exudation was reduced.
  
  
  CONCLUSIONS
  After OHR, lysine decarboxylase activity seems to determine biofilm lysine content and biofilm accumulation. When biofilm lysine exceeds minimal blood plasma content after OHR, less GCF appeared despite more biofilm. Lysine appears important for biofilm accumulation and the epithelial barrier to bacterial proinflammatory agents. Inhibiting lysine decarboxylase may retard the increased GCF exudation required for microbial development and gingivitis.
authors.affiliation: Department of Conservative Dentistry, Semmelweis University, Budapest, Hungary.
authors.forename: Zsolt
authors.initials: Z
authors.lastname: Lohinai
authors.forename: Beata
authors.initials: B
authors.lastname: Keremi
authors.forename: Eva
authors.initials: E
authors.lastname: Szoko
authors.forename: Tamas
authors.initials: T
authors.lastname: Tabi
authors.forename: Csaba
authors.initials: C
authors.lastname: Szabo
authors.forename: Zsolt
authors.initials: Z
authors.lastname: Tulassay
authors.forename: Martin
authors.initials: M
authors.lastname: Levine
mesh_terms: D000328:Adult; D018441:Biofilms / Q000254:growth & development*; D002103:Cadaverine / Q000032:analysis; D002262:Carboxy-Lyases / Q000502:physiology*; D003774:Dental Plaque Index; D019075:Electrophoresis, Capillary; D005260:Female; D005500:Follow-Up Studies; D005883:Gingival Crevicular Fluid / Q000737:chemistry / Q000378:metabolism; D005891:Gingivitis / Q000209:etiology*; D006801:Humans; D008239:Lysine / Q000032:analysis* / Q000097:blood; D008297:Male; D009910:Oral Hygiene; D011700:Putrescine / Q000032:analysis; D012463:Saliva / Q000737:chemistry; D055815:Young Adult
chemical_list: D002262:Carboxy-Lyases; C021520:lysine decarboxylase; D008239:Lysine; D002103:Cadaverine; D011700:Putrescine