title: Microvascular blood flow dynamics associated with photodynamic therapy, pulsed dye laser irradiation and combined regimens.
abstract: OBJECTIVE
  Previous in vitro studies demonstrated the potential utility of benzoporphyrin derivative monoacid ring A (BPD) photodynamic therapy (PDT) for vascular destruction. Moreover, the effects of PDT were enhanced when this intervention was followed immediately by pulsed dye laser (PDL) irradiation (PDT/PDL). We further evaluate vascular effects of PDT alone, PDL alone and PDT/PDL in an in vivo rodent dorsal skinfold model.
  
  
  METHODS
  A dorsal skinfold window chamber was installed surgically on female Sprague-Dawley rats. One milligram per kilogram of BPD solution was administered intravenously via a jugular venous catheter. Evaluated interventions were: control (no BPD, no light), PDT alone (576 nm, 16 minutes exposure time, 15 minutes post-BPD injection, 10 mm spot), PDL alone at 7 J/cm2 (585 nm, 1.5 ms pulse duration, 7 mm spot), PDL alone at 10 J/cm2, PDT/PDL (PDL at 7 J/cm2), and PDT/PDL (PDL at 10 J/cm2). To assess changes in microvascular blood flow, laser speckle imaging was performed before, immediately after, and 18 hours post-intervention.
  
  
  RESULTS
  Epidermal irradiation was accomplished without blistering, scabbing or ulceration. A reduction in perfusion was achieved in all intervention groups. PDT/PDL at 7 J/cm2 resulted in the greatest reduction in vascular perfusion (56%).
  
  
  CONCLUSIONS
  BPD PDT can achieve safe and selective vascular flow reduction. PDT/PDL can enhance diminution of microvascular blood flow. Our results suggest that PDT and PDT/PDL should be evaluated as alternative therapeutic options for treatment of hypervascular skin lesions including port wine stain birthmarks.
authors.affiliation: Beckman Laser Institute, University of California, Irvine, California 92612, USA.
authors.forename: Tia K
authors.initials: TK
authors.lastname: Smith
authors.forename: Bernard
authors.initials: B
authors.lastname: Choi
authors.forename: Julio C
authors.initials: JC
authors.lastname: Ramirez-San-Juan
authors.forename: J Stuart
authors.initials: JS
authors.lastname: Nelson
authors.forename: Kathryn
authors.initials: K
authors.lastname: Osann
authors.forename: Kristen M
authors.initials: KM
authors.lastname: Kelly
mesh_terms: D000818:Animals; D005260:Female; D028022:Low-Level Light Therapy; D008833:Microcirculation; D023421:Models, Animal; D010778:Photochemotherapy; D017319:Photosensitizing Agents / Q000494:pharmacology*; D011166:Porphyrins / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012039:Regional Blood Flow; D012867:Skin / Q000098:blood supply*; D000077362:Verteporfin
chemical_list: D017319:Photosensitizing Agents; D011166:Porphyrins; D000077362:Verteporfin