title: Expression of nerve growth factor receptors on the ocular surface in healthy subjects and during manifestation of inflammatory diseases.
abstract: OBJECTIVE
  Recent studies have suggested the involvement of nerve growth factor (NGF) in the conjunctival inflammatory process and in corneal epithelium proliferation and differentiation. To verify the hypothesis that NGF could locally modulate the inflammatory and reparative processes, the authors evaluated the expression of NGF high-affinity receptor on the ocular surface in normal and pathologic conditions.
  
  
  METHODS
  Ten conjunctival biopsies (obtained from three healthy subjects, five patients affected by vernal keratoconjunctivitis [VKC], and two patients with cicatricial pemphigoid [CP]) and five corneal specimens obtained from the Eye Bank of Veneto (Italy) were evaluated. All specimens were histologically stained, and immunohistochemistry was performed to identify the NGF high-affinity receptor (TrkA).
  
  
  RESULTS
  All tissues expressed immunoreactivity for NGF receptors. In conjunctival specimens of healthy subjects, basal epithelial cells strongly expressed immunoreactivity and, in the stroma, rare cells were immunopositive for TrkA. No significant difference in immunoreactivity was observed in the conjunctival epithelium between healthy subjects and patients with inflammatory conjunctival diseases, whereas there were more immunopositive cells observed in the conjunctival stroma of VKC and CP patients than in the controls. The immunoreactivity in the cornea was confined to basal epithelial cells and endothelium.
  
  
  CONCLUSIONS
  The NGF receptor is present on the human ocular surface. The authors' data support the possibility that NGF modulates ocular inflammation and corneal epithelial proliferation and differentiation through its receptors.
authors.affiliation: Institute of Neurobiology, National Research Council, Rome, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Lambiase
authors.forename: S
authors.initials: S
authors.lastname: Bonini
authors.forename: A
authors.initials: A
authors.lastname: Micera
authors.forename: P
authors.initials: P
authors.lastname: Rama
authors.forename: S
authors.initials: S
authors.lastname: Bonini
authors.forename: L
authors.initials: L
authors.lastname: Aloe
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D003228:Conjunctiva / Q000378:metabolism*; D003229:Conjunctival Diseases / Q000378:metabolism / Q000473:pathology; D003233:Conjunctivitis, Allergic / Q000378:metabolism* / Q000473:pathology; D003315:Cornea / Q000378:metabolism; D004804:Eosinophils / Q000378:metabolism / Q000473:pathology; D004847:Epithelial Cells / Q000378:metabolism; D005260:Female; D019084:Fluorescent Antibody Technique, Indirect; D006801:Humans; D007124:Immunoenzyme Techniques; D008297:Male; D008875:Middle Aged; D010390:Pemphigoid, Benign Mucous Membrane / Q000378:metabolism* / Q000473:pathology; D011518:Proto-Oncogene Proteins / Q000378:metabolism*; D020794:Receptor Protein-Tyrosine Kinases / Q000378:metabolism*; D020917:Receptor, trkA; D017475:Receptors, Nerve Growth Factor / Q000378:metabolism*; D013601:T-Lymphocytes / Q000378:metabolism / Q000473:pathology
chemical_list: D011518:Proto-Oncogene Proteins; D017475:Receptors, Nerve Growth Factor; D020794:Receptor Protein-Tyrosine Kinases; D020917:Receptor, trkA