The effect of antimicrobial photodynamic therapy on human ciliated respiratory mucosa

Abstract

Background Chronic recurrent sinusitis (CRS) is one of the most common chronic conditions in the United States. There is a significant subpopulation of CRS patients who remain resistant to cure despite rigorous treatment regimens including surgery, allergy therapy and prolonged antibiotic therapy. Antimicrobial photodynamic therapy (aPDT) is a non-invasive non-antibiotic broad spectrum antimicrobial treatment. Our previous in vitro studies demonstrated that aPDT reduced CRS polymicrobial biofilm and planktonic bacteria and fungi by >99.9% after a single treatment. Prior to human treatment however, aPDT treatment must be demonstrated to not result in histologic damage to the sinus ciliated respiratory epithelium. The objective of this study was to demonstrate the safety of aPDT treatment on a living human ciliated respiratory mucosal model (EpiAirway™). Methods A study of aPDT treatment of EpiAirway™ was performed. Treatment groups included a non-treatment control, laser light alone, photosensitizer alone and therapeutic photosensitizer and light combination (aPDT). At completion of treatment, the EpiAirway™ tissue was fixed in 10% formalin, paraffin-embedded, sectioned, H &E stained and mounted. All samples were blinded and microscopically examined by a human pathologist to assess any effect of aPDT on the tissue, cilia or mucosal glands. The results were correlated with the treatment parameters. Results The EpiAirway™ histologic study demonstrated no histologic alteration of the respiratory cilia or mucosal epithelium in any of the treatment groups. Conclusions aPDT is a safe treatment for CRS resulting in no histologic alteration of human ciliated respiratory mucosa as is found in the human sinuses.

International Consensus Statement on Allergy and Rhinology: Rhinosinusitis

“…[344][345][346][347] Photodynamic therapy is a new and promising treatment that shows tremendous biofilm reductions in vitro, and preliminary tissue studies have not shown deleterious side effects. 348,349 Last, low-frequency ultrasound treatments also seem effective in reducing biofilms, also without observed side effects. 350 A promising new approach to understanding biofilms involves bitter taste receptors in the upper respiratory tract.…”

New innovations in office-based rhinology

“…In an in-vitro model, Biel et al [33,34 && ] demonstrated that photodynamic therapy diminished MRSA and antibiotic-resistant Pseudomonas aeruginosa biofilms by over 99% after a single treatment. In addition, it has been shown that photodisinfection does not affect normal human-ciliated respiratory mucosa at a histological level, and that no 'photoresistance' occurs with repetitive treatment [35]. Clinical trials investigating the efficacy of photodisinfection in the treatment of CRS are currently being conducted [36].…”

Understanding the Role of Biofilms and Superantigens in Chronic Rhinosinusitis

“…aDPT has also demonstrated efficacy in preventing surgical site infections when used in pre-operative decolonization therapy in conjunction with chlorhexidine body wipes, in the treatment of chronic periodontitis, and in reducing biofilm formation on orthopedic prosthetic devices [81–83]. aPDT does not cause histologic damage to the underlying respiratory mucosa and appears to be a promising and viable option for biofilm eradication, especially in antibiotic resistant cases [84]. …”