title: Nerve Growth Factor Expression and Its Receptors TrkA and p75NTR in Peri-Implantitis Lesions.
abstract: BACKGROUND
  Nerve growth factor (NGF) can, through its receptors TrkA and p75NTR, convey signals for cell survival or cell differentiation. These proteins are also involved in inflammation and in bone resorption. The aim of this study is to evaluate, for the first time, the expression of NGF and its receptors TrkA and p75NTR in peri-implantitis lesions.
  
  
  METHODS
  Fifteen biopsy specimens from patients with chronic peri-implantitis and 4 of healthy oral mucosa were immunostained with antibodies against NGF, TrkA, and p75NTR. The staining intensity and percentage of stained cells were semi-quantitatively evaluated and results were compared between the 2 groups.
  
  
  RESULTS
  In the peri-implant pocket epithelium and gingival epithelium, NGF and TrkA expressions were similar to the healthy oral mucosa, however, a decreased expression of p75NTR was observed. In all cases, more than 75% of the inflammatory cells stained positively for NGF and TrkA, and p75NTR was negatively expressed.
  
  
  CONCLUSIONS
  The intense expression of NGF and TrkA in the inflammatory cell infiltrate associated with decreased expression of p75NTR in both gingival and pocket epithelium suggests that these proteins may have a role in peri-implantitis lesions.
authors.affiliation: *Postgraduate in Oral Surgery, Laboratory of Oral Medicine, Oral Maxillofacial Pathology Unit, Division of Oral Maxillofacial Surgery, Department of Surgery, Geneva University Hospitals-HUG, Geneva, Switzerland. †Research Fellow, Laboratory of Oral Medicine, Oral Maxillofacial Pathology Unit, Division of Oral Maxillofacial Surgery, Department of Surgery, Geneva University Hospitals-HUG, Geneva, Switzerland. ‡Head, Laboratory of Oral Medicine, Oral Maxillofacial Pathology Unit, Division of Oral Maxillofacial Surgery, Department of Surgery, Geneva University Hospitals-HUG, Geneva, Switzerland.
authors.forename: T
authors.initials: T
authors.lastname: Douillard
authors.forename: C P
authors.initials: CP
authors.lastname: Martinelli-Kläy
authors.forename: Tommaso
authors.initials: T
authors.lastname: Lombardi
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D005881:Gingiva / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009061:Mouth Mucosa / Q000378:metabolism / Q000473:pathology / Q000502:physiology; D020932:Nerve Growth Factor / Q000378:metabolism* / Q000502:physiology; D009419:Nerve Tissue Proteins / Q000378:metabolism* / Q000502:physiology; D057873:Peri-Implantitis / Q000378:metabolism* / Q000473:pathology / Q000503:physiopathology; D020917:Receptor, trkA / Q000378:metabolism* / Q000502:physiology; D017475:Receptors, Nerve Growth Factor / Q000378:metabolism* / Q000502:physiology; D012189:Retrospective Studies
chemical_list: C484065:NGFR protein, human; C000611485:NTRK1 protein, human; D009419:Nerve Tissue Proteins; D017475:Receptors, Nerve Growth Factor; D020932:Nerve Growth Factor; D020917:Receptor, trkA