title: Pneumonia treatment by photodynamic therapy with extracorporeal illumination - an experimental model.
abstract: Infectious pneumonia is a major cause of morbidity/mortality, mainly because of the increasing rate of microorganisms resistant to antibiotics. Photodynamic Therapy (PDT) is emerging as a promising approach, as effects are based on oxidative stress, preventing microorganism resistance. In two previous studies, the in vitro inactivation ofStreptococcus pneumoniaeusing indocyanine green (ICG) and infrared light source was a success killing 5 log10colony-forming units (CFU/mL) with only 10μmol/L ICG. In this work, a proof-of-principle protocol was designed to treat lung infections by PDT using extracorporeal illumination with a 780 nm laser device and also ICG as photosensitizer. Hairless mice were infected withS. pneumoniaeand PDT was performed two days after infection. For control groups, CFU recovery ranged between 103-104/mouse. For PDT group, however, no bacteria were recovered in 80% of the animals. Based on this result, animal survival was evaluated separately over 50 days. No deaths occurred in PDT group, whereas 60% of the control group died. Our results indicate that extracorporeal PDT has the potential for pneumonia treatment, and pulmonary decontamination with PDT may be used as a single therapy or as an antibiotics adjuvant.
authors.affiliation: University of São Paulo, São Carlos, Brazil mcgeralde@outlook.com.|Federal University of São Carlos, São Carlos, Brazil.
authors.forename: Mariana C
authors.initials: MC
authors.lastname: Geralde
authors.affiliation: University of São Paulo, São Carlos, Brazil.
authors.forename: Ilaiáli S
authors.initials: IS
authors.lastname: Leite
authors.affiliation: University of São Paulo, São Carlos, Brazil.
authors.forename: Natalia M
authors.initials: NM
authors.lastname: Inada
authors.affiliation: São Paulo State University, Araraquara, Brazil.
authors.forename: Ana Carolina G
authors.initials: AC
authors.lastname: Salina
authors.affiliation: São Paulo State University, Araraquara, Brazil.
authors.forename: Alexandra I
authors.initials: AI
authors.lastname: Medeiros
authors.affiliation: Keenan Research Centre of St. Michael's Hospital, Toronto, Ontario, Canada.
authors.forename: Wolfgang M
authors.initials: WM
authors.lastname: Kuebler
authors.affiliation: University of São Paulo, São Carlos, Brazil.
authors.forename: Cristina
authors.initials: C
authors.lastname: Kurachi
authors.affiliation: University of São Paulo, São Carlos, Brazil.
authors.forename: Vanderlei S
authors.initials: VS
authors.lastname: Bagnato
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D007208:Indocyanine Green / Q000494:pharmacology; D051379:Mice; D010778:Photochemotherapy / Q000379:methods*; D017319:Photosensitizing Agents / Q000494:pharmacology*; D010789:Phototherapy / Q000379:methods*; D011018:Pneumonia, Pneumococcal / Q000628:therapy*; D013296:Streptococcus pneumoniae; D016896:Treatment Outcome
chemical_list: D017319:Photosensitizing Agents; D007208:Indocyanine Green
keywords: 
  Streptococcus pneumoniae
  ; Extracorporeal illumination; indocyanine green; photodynamic therapy; pneumonia