title: Effect of aspirin on photodynamic therapy utilizing chloroaluminum sulfonated phthalocyanine (CASP).
abstract: The efficacy of photodynamic therapy (PDT) is mediated through a direct vascular effect. Interference with platelet function and resulting vascular stasis have been recently demonstrated utilizing the photosensitizer dihematoporphyrin ether (DHE). We examined the effect of aspirin, a known inhibitor of both cyclooxygenase and platelet activity, on PDT using chloroaluminum sulfonated phthalocyanine (CASP). Thirty-six rats implanted with a window chamber were given either 0.1 mg/kg (low dose) or 10 mg/kg (high dose) aspirin immediately before, immediately after, or 6 hours after the completion of CASP-PDT. Aspirin in either dosage did not appear to have any effect on the window vasculature when given immediately after light exposure. A moderate inhibition of vascular response was seen in animals treated with aspirin pre-PDT, whereas high-dose aspirin completely abrogated the CASP-PDT vascular response when given 6 hours post-PDT. These data indicate that aspirin can effect CASP-PDT in both time-dependent and dose-dependent fashions.
authors.affiliation: Department of Head and Neck Surgery, University of Texas M.D. Anderson Cancer Center, Houston 77030.
authors.forename: S J
authors.initials: SJ
authors.lastname: Stern
authors.forename: J R
authors.initials: JR
authors.lastname: Craig
authors.forename: S
authors.initials: S
authors.lastname: Flock
authors.forename: S
authors.initials: S
authors.lastname: Small
mesh_terms: D000818:Animals; D001241:Aspirin / Q000494:pharmacology*; D007211:Indoles / Q000627:therapeutic use*; D009942:Organometallic Compounds / Q000627:therapeutic use*; D010778:Photochemotherapy; D011838:Radiation-Sensitizing Agents / Q000627:therapeutic use; D051381:Rats; D011916:Rats, Inbred F344; D012867:Skin / Q000098:blood supply / Q000187:drug effects / Q000528:radiation effects; D012884:Skin Window Technique; D013053:Spectrophotometry
chemical_list: D007211:Indoles; D009942:Organometallic Compounds; D011838:Radiation-Sensitizing Agents; C052736:chloroaluminum tetrasulfophthalocyanine; D001241:Aspirin