title: Decreased levels of metalloproteinase-9 and angiogenic factors in skin lesions of patients with psoriatic arthritis after therapy with anti-TNF-alpha.
abstract: BACKGROUND
  Inflammation represents an early and key event in the development of both the cutaneous psoriasis and psoriatic arthritis. Compelling evidences indicate that the production of TNF-alpha plays a central role in psoriasis by sustaining the inflammatory process in the skin as well as in the joints. Among the multiple effects produced by TNF-alpha on keratinocytes, the induction of matrix metalloproteinase-9 (MMP-9), a collagenase implicated in joint inflammatory arthritis which acts as an angiogenesis promoting factor, might represent a key mechanism in the pathogenesis of the disease. Aims of the present study were to investigate a) the role of MMP-9 in the development of psoriasis by assessing the presence of MMP-9 in lesional skin and in sera of psoriatic patients; b) the association of MMP-9 with the activity of the disease; c) the relationship between MMP-9 and TNF-alpha production.
  
  
  METHODS
  Eleven psoriatic patients, clinically presenting joint symptoms associated to the cutaneous disease, were included in a therapeutic protocol based on the administration of anti-TNF-alpha monoclonal antibody (Infliximab). Sera and skin biopsies were collected before treatment and after 6 weeks of therapy. Tissues were kept in short term cultures and production soluble mediators such as TNF-alpha, MMP-9, MMP-2, VEGF and E-Selectin, which include angiogenic molecules associated to the development of plaque psoriasis, were measured in the culture supernatants by immunoenzymatic assays (ng/ml or pg/ml per mg of tissue). MMP-9 concentrations were also measured in the sera. The cutaneous activity of disease was evaluated by the Psoriasis Area and Severity Index (PASI).
  
  
  RESULTS
  Clinical and laboratory assessment indicated that all but one patients had a significant improvement of the PASI score after three months of therapy. The clinical amelioration was associated to a significant decrease of MMP-9 (P = 0.017), TNF-alpha (P = 0.005) and E-selectin (P = 0.018) levels, spontaneously released by lesional biopsies before and after therapy. In addition, significant correlations were found between the PASI measurements and TNF-alpha (r2 = 0.33, P = 0.005), MMP-9 (r2 = 0.25, P = 0.017), E-selectin (r2 = 0.24, P = 0.018) production. MMP-9 levels were significantly correlated with those of TNF-alpha (r2 = 0.30, P = 0.008). A significant decrease of MMP-9 in the sera, associated to the clinical improvement was also found.
  
  
  CONCLUSIONS
  Our findings show the existence of a direct relationship between MMP-9 and TNF-alpha production strongly suggesting that MMP-9 may play a key role in the skin inflammatory process in psoriasis.
authors.affiliation: Clinical Pathology and Microbiology Laboratory, San Gallicano Dermatology Institute, 00144 Rome, Italy. cordiali-fei@ifo.it
authors.forename: Paola
authors.initials: P
authors.lastname: Cordiali-Fei
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Trento
authors.forename: Giovanna
authors.initials: G
authors.lastname: D'Agosto
authors.forename: Valentina
authors.initials: V
authors.lastname: Bordignon
authors.forename: Anna
authors.initials: A
authors.lastname: Mussi
authors.forename: Marco
authors.initials: M
authors.lastname: Ardigò
authors.forename: Antonio
authors.initials: A
authors.lastname: Mastroianni
authors.forename: Antonella
authors.initials: A
authors.lastname: Vento
authors.forename: Francesco
authors.initials: F
authors.lastname: Solivetti
authors.forename: Enzo
authors.initials: E
authors.lastname: Berardesca
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Ensoli