title: Responses of human neutrophils to nicotine and/or Porphyromonas gingivalis.
abstract: BACKGROUND
  Tobacco smoking is considered a major modifiable risk factor for periodontal disease. Nicotine is the addictive ingredient in tobacco and has been shown to affect multiple cellular processes. Neutrophils are the first line of host defense and are critical cells in the maintenance of periodontal health through their role in the control of bacteria, but they can also contribute to the progression of periodontal disease by the production and release of reactive oxygen species (ROS). Virulence factors from periodontal pathogens, such as Porphyromonas gingivalis (Pg), stimulate the respiratory burst of neutrophils. The objective of this study is to explore the oxidative activity of neutrophils when stimulated with Pg, nicotine, or both.
  
  
  METHODS
  Neutrophils were separated from buffy coats by the double dextran gradient method. The generation of ROS by neutrophils was determined using luminol-dependent chemiluminescence assays. The reaction was followed for 90 minutes, and the neutrophil activation was recorded as the total integrated energy output.
  
  
  RESULTS
  The Pg and Pg plus nicotine groups had a significantly higher active and peak chemiluminescence than the nicotine group (all with P <0.0001). The Pg and Pg with nicotine groups were not significantly different (P = 0.90).
  
  
  CONCLUSIONS
  In the presence of Pg, the nicotine did not further enhance the ROS release by the neutrophils, suggesting that the bacteria induced the maximum ROS release in this model system.
authors.affiliation: Department of Oral Biology, Indiana University School of Dentistry, Indianapolis, IN 46202, USA.
authors.forename: Nouf K
authors.initials: NK
authors.lastname: Al-Shibani
authors.forename: Nawaf Y
authors.initials: NY
authors.lastname: Labban
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Kowolik
authors.forename: John D
authors.initials: JD
authors.lastname: Ruby
authors.forename: L Jack
authors.initials: LJ
authors.lastname: Windsor
mesh_terms: D000704:Analysis of Variance; D017077:Culture Media, Conditioned / Q000494:pharmacology; D006801:Humans; D009504:Neutrophils / Q000187:drug effects* / Q000378:metabolism; D009538:Nicotine / Q000494:pharmacology*; D018722:Nicotinic Agonists / Q000494:pharmacology*; D016966:Porphyromonas gingivalis / Q000737:chemistry; D017382:Reactive Oxygen Species / Q000378:metabolism*; D016897:Respiratory Burst / Q000187:drug effects; D037521:Virulence Factors / Q000494:pharmacology*
chemical_list: D017077:Culture Media, Conditioned; D018722:Nicotinic Agonists; D017382:Reactive Oxygen Species; D037521:Virulence Factors; D009538:Nicotine