title: Animal models for photodynamic therapy (PDT).
abstract: Photodynamic therapy (PDT) employs non-toxic dyes called photosensitizers (PSs), which absorb visible light to give the excited singlet state, followed by the long-lived triplet state that can undergo photochemistry. In the presence of ambient oxygen, reactive oxygen species (ROS), such as singlet oxygen and hydroxyl radicals are formed that are able to kill cancer cells, inactivate microbial pathogens and destroy unwanted tissue. Although there are already several clinically approved PSs for various disease indications, many studies around the world are using animal models to investigate the further utility of PDT. The present review will cover the main groups of animal models that have been described in the literature. Cancer comprises the single biggest group of models including syngeneic mouse/rat tumours that can either be subcutaneous or orthotopic and allow the study of anti-tumour immune response; human tumours that need to be implanted in immunosuppressed hosts; carcinogen-induced tumours; and mice that have been genetically engineered to develop cancer (often by pathways similar to those in patients). Infections are the second biggest class of animal models and the anatomical sites include wounds, burns, oral cavity, ears, eyes, nose etc. Responsible pathogens can include Gram-positive and Gram-negative bacteria, fungi, viruses and parasites. A smaller and diverse group of miscellaneous animal models have been reported that allow PDT to be tested in ophthalmology, atherosclerosis, atrial fibrillation, dermatology and wound healing. Successful studies using animal models of PDT are blazing the trail for tomorrow's clinical approvals.
authors.affiliation: Massachusetts General Hospital, Wellman Center for Photomedicine, Boston, MA 02114, U.S.A. Harvard Medical School, Department of Dermatology, Boston, MA 02114, U.S.A. Postgraduate Program in Biophotonics Applied to Health Sciences, Nove de Julho University, São Paulo, SP 02117-010, Brazil.
authors.forename: Zenildo Santos
authors.initials: ZS
authors.lastname: Silva
authors.affiliation: Postgraduate Program in Biophotonics Applied to Health Sciences, Nove de Julho University, São Paulo, SP 02117-010, Brazil.
authors.forename: Sandra Kalil
authors.initials: SK
authors.lastname: Bussadori
authors.affiliation: Postgraduate Program in Biophotonics Applied to Health Sciences, Nove de Julho University, São Paulo, SP 02117-010, Brazil.
authors.forename: Kristianne Porta Santos
authors.initials: KP
authors.lastname: Fernandes
authors.affiliation: Massachusetts General Hospital, Wellman Center for Photomedicine, Boston, MA 02114, U.S.A. Harvard Medical School, Department of Dermatology, Boston, MA 02114, U.S.A.
authors.forename: Ying-Ying
authors.initials: YY
authors.lastname: Huang
authors.affiliation: Massachusetts General Hospital, Wellman Center for Photomedicine, Boston, MA 02114, U.S.A. Harvard Medical School, Department of Dermatology, Boston, MA 02114, U.S.A. Harvard-MIT Division of Health Sciences and Technology, Cambridge, MA 02139, U.S.A. hamblin@helix.mgh.harvard.edu.
authors.forename: Michael R
authors.initials: MR
authors.lastname: Hamblin
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D006801:Humans; D051379:Mice; D009369:Neoplasms / Q000378:metabolism / Q000473:pathology / Q000628:therapy*; D010778:Photochemotherapy; D051381:Rats; D017382:Reactive Oxygen Species / Q000378:metabolism*
chemical_list: D017382:Reactive Oxygen Species
keywords: autochthonous; cancer; genetically-engineered mouse model; infection; orthotopic tumour; photodynamic therapy; subcutaneous tumour; xenograft