PERSPEKTYWY ZASTOSOWANIA
FOTODYNAMICZNEJ TERAPII SKIEROWANEJ
PRZECIW MIKROORGANIZMOM - PACT
Tomasz Gośliński1*, Krystyna Konopka2, Jarosław Piskorz1
Michał Kryjewski1, Marcin Wierzchowski1, Stanisław Sobiak1
1Katedra i Zakład Technologii Chemicznej Środków Leczniczych Uniwersytet Medyczny im. Karola Marcinkowskiego, Poznań, ![Mail to... list](../images/email.jpg)
2Department of Microbiology, University of the Pacific, Arthur A. Dugoni School of Dentistry San Francisco, USA, ![Mail to... list](../images/email.jpg)
Wpłynęło w lutym 2008 r.
1. Wprowadzenie. 2. Mechanizmy reakcji fotodynamicznej i terapii fotodynamicznej. 3. Źródła światła. 4. Fotosensybilizatory. 5. Terapia fotodynamiczna skierowana przeciw mikroorganizmom (PACT). 5.1. Badania PACT in vitro. 5.2. Efekty PACT badane na biofilmach. 5.3. Badania PACT in vivo. 5.4. Fotodynamiczna inaktywacja patogenów. 6. Perspektywy i kierunki badań
Prospects for Photodynamic Antimicrobial Chemotherapy - PACT
Abstract: Photodynamic therapy (PDT), also known as photoradiation therapy, phototherapy, or photochemotherapy, is a medical treatment that utilizes light to activate a photosensitizing agent (photosensitizer) in the presence of oxygen. The exposure of the photosensitizer to light of a specific wavelength results in the formation of oxygen species, such as singlet oxygen and free radicals, causing localized photodamage and cell death. Applications of PDT in
the treatment of cancer and in the photodynamic diagnosis (PDD) of tumors and skin diseases are growing rapidly. There is also increased attention in photodynamic antimicrobial chemotherapy (PACT) that may represent an alternative treatment for drug resistant organisms. PACT has been effective in the treatment of bacterial, fungal, parasitic, and viral infections. The localized infections of the skin and the oral cavity are especially suitable for PACT since they
are relatively accessible to illumination. The development of resistance to PACT appears to be unlikely, because in microbial cells singlet oxygen and free radicals interact with several cell structures and different metabolic pathways. PACT is equally effective against antibiotic-resistant and antibiotic-susceptible bacteria, and repeated photosensitization has not induced the selection of resistant strains. Bacteria that grow in biofilms, implicated in diseases
like cystic fibrosis (Pseudomonas aeruginosa) or periodontitis (Porphyromonas gingivalis), are also susceptible to PDT. Studies are now leading towards selective photosensitizers, since killing the entire flora leaves patients open to opportunistic infections. Several publications have summarized the photobiology of PACT in vitro, and its potential for the treatment of localized infections, but only a few studies have evaluated the use of
PACT in animal models or in clinical trials. Pre-clinical work has shown that photosensitizers are more toxic against microbial species than against mammalian cells, that the illumination-based toxicity occurs much earlier in prokaryotic (bacteria) than in eukaryotic (fungi) cells, and that Gram-positive bacteria are more sensitive to PACT than Gram-negative species. PACT will not replace antimicrobial chemotherapy, but the photodynamic approach may improve the
treatment of localized infections, speeding up and lowering the cost of the treatment. Development of new photosensitizers and more efficient light delivery systems, and further animal studies are required to establish the optimum treatment parameters for PACT before proceeding to clinical trials and eventual clinical use.
1. Introduction. 2. Mechanisms of photodynamic reaction and photodynamic therapy. 3. Light sources. 4. Photosensitizers. 5. Photodynamic antimicrobial chemotherapy (PACT). 5.1. In vitro studies of PACT. 5.2. Effects of PACT on biofilms. 5.3. In vivo studies of PACT. 5.4. Photodynamic inactivation of pathogens. 6. Perspectives andfuture directions
Słowa kluczowe: biofilmy, fotosensybilizatory, terapia fotodynamiczna, terapia fotodynamiczna skierowana przeciw mikroorganizmom
Key words: biofilms, photodynamic therapy, photodynamic antimicrobial chemotherapy, photosensitizers
* Adres do korespondencji: Uniwersytet Medyczny im. Karola Marcinkowskiego, Katedra i Zakład Technologii Chemicznej Środków Leczniczych (Wydział Farmaceutyczny), ul. Grunwaldzka 6, 60-780 Poznań, tel.: (0 61) 854-66-37, Fax: (0 61) 854-66-39, ![Mail to... list](../images/email.jpg)
|