Photodynamic therapy of cottontail rabbit papillomavirus-induced papillomas in a severe combined immunodeficient mouse xenograft system

Mucosal Injection of the Silicon Phthalocyanine Pc 4 in a Rabbit Model-A Pilot Study

OBJECTIVE

The silicon phthalocyanine Pc 4 is a photosensitizing agent previously shown to be a promising treatment for cutaneous neoplasms using photodynamic therapy (PDT). Based on prior preclinical studies, we believe Pc 4-PDT has potential as a targeted treatment of human recurrent respiratory papillomatosis or laryngeal leukoplakia by direct injection into mucosal surfaces.

METHODS

This was a proof-of-concept pilot study assessing direct mucosal injection of Pc 4 into buccal and vocal fold mucosae in a rabbit model. Five New Zealand white rabbits underwent tattooing of bilateral buccal mucosae to delineate injection sites, followed by submucosal injections of control and Pc 4 solutions. Rabbits were monitored for post-injection tolerance. Punch biopsies were obtained from injected mucosa and assessed histopathologically. Once the buccal mucosa was found to be tolerant, vocal folds of three rabbits were injected. The rabbits were then sacrificed, and laryngeal tissue was assessed histopathologically.

RESULTS

All rabbits tolerated injection of Pc 4 and control solutions into buccal mucosa with no evidence of gross visual inflammatory changes and no changes in behavior or masticatory function. Histopathologic analysis of Pc 4 injected buccal and control mucosal tissue revealed mild focal histological changes and no stigmata of diffuse inflammatory reactions. The histopathologic analysis of Pc 4 injected into laryngeal tissue revealed similar findings with addition of mild eosinophilia in one sample.

CONCLUSION

Direct mucosal injection of Pc 4 in rabbit buccal and vocal fold mucosae appears to be well tolerated with no gross inflammatory changes, and only mild histopathologic inflammatory changes observed.

LEVEL OF EVIDENCE

NA Laryngoscope, 135:270-276, 2025.

A systematic review of photodynamic therapy as an antiviral treatment: Potential guidance for dealing with SARS-CoV-2

BACKGROUND

SARS-CoV-2, which causes the coronavirus disease (COVID-19), presents high rates of morbidity and mortality around the world. The search to eliminate SARS-CoV-2 is ongoing and urgent. This systematic review seeks to assess whether photodynamic therapy (PDT) could be effective in SARS-CoV-2 inactivation.

METHODS

The focus question was: Can photodynamic therapy be used as potential guidance for dealing with SARS-CoV-2?". A literature search, according to PRISMA statements, was conducted in the electronic databases PubMed, EMBASE, SCOPUS, Web of Science, LILACS, and Google Scholar. Studies published from January 2004 to June 2020 were analyzed. In vitro and in vivo studies were included that evaluated the effect of PDT mediated by several photosensitizers on RNA and DNA enveloped and non-enveloped viruses.

RESULTS

From 27 selected manuscripts, 26 publications used in vitro studies, 24 were exclusively in vitro, and two had in vitro/in vivo parts. Only one analyzed publication was exclusively in vivo. Meta-analysis studies were unfeasible due to heterogeneity of the data. The risk of bias was analyzed in all studies.

CONCLUSION

The in vitro and in vivo studies selected in this systematic review indicated that PDT is capable of photoinactivating enveloped and non-enveloped DNA and RNA viruses, suggesting that PDT can potentially photoinactivate SARS-CoV-2.

Photobiomodulation and Antiviral Photodynamic Therapy in COVID-19 Management

Coronavirus disease 2019 (COVID-19) has shocked the world by its spread and contagiousness. There is no approved vaccine and no proven treatment for this infection. Some potential treatments that have already been associated with antiviral and anti-inflammatory effects are under investigation. Photobiomodulation therapy (PBMT) is a photon-based therapy that uses light to mediate a variety of metabolic, analgesic, anti-inflammatory, and immunomodulatory effects. Antiviral photodynamic therapy (aPDT) is a branch of photodynamic therapy based on the reaction between a photosensitizing agent and a light source in the presence of oxygen, which can produce oxidative and free radical agents to damage the viral structures such as proteins and nucleic acids. This chapter aims to discuss the potential therapeutic benefit of PBMT and aPDT in the context of the novel coronavirus. Studies indicate that PBMT and aPDT could be useful in many viral and bacterial pulmonary complications like influenza, SARS-CoV, and MERS, but we found no direct study on SARS-CoV-2. With a combination of PBMT and aPDT, we may be able to combat COVID-19 with minimal interference with pharmaceutical agents. It might improve the efficacy of PBMT and aPDT by using monoclonal antibodies and preparing new photosensitizers at the nanoscale that target the lung tissue specifically. More animal and human studies would need to take place to reach an effective protocol. This chapter would encourage other scientists to work on this new platform.

Topical 5-aminolevulinic acid photodynamic therapy for laryngeal papillomatosistosis treatment

BACKGROUND

To explore the therapeutic effect of topical 5-Aminolevulinic Acid photodynamic therapy (ALA-PDT) on laryngeal papillomatosis (LP) treatment.

METHODS

13 patients with LP underwent topical ALA-PDT after tumor resection (CO₂laser or/and microdebrider resection). All patients were irradiated 3-4 times. After ALA-PDT treatment, the laryngoscopic examination was performed every 1-2 months to observe the therapeutic effect.

RESULTS

All 13 patients were followed up for more than 1 year. Eleven cases (84.6%) showed no recurrence; two cases (15.4%) had relapses. One child developed III° inspiratory dyspnea caused by laryngeal mucosal edema and need endotracheal intubation again. Four patients had adhesion of the anterior commissure of the vocal cord. The detection rate of HPV infections was 76.9% and two patients had multiple HPV subtype co-infection.

CONCLUSIONS

The preliminary effect of topical ALA-PDT significantly reduces recurrence and improves the cure rate of LP. Further research on this treatment is still required.

Advances in Designing and Developing Vaccines, Drugs and Therapeutic Approaches to Counter Human Papilloma Virus

Human papillomavirus (HPV) is a viral infection with skin-to-skin based transmission mode. HPV annually caused over 500,000 cancer cases including cervical, anogenital and oropharyngeal cancer among others. HPV vaccination has become a public-health concern, worldwide, to prevent the cases of HPV infections including precancerous lesions, cervical cancers, and genital warts especially in adolescent female and male population by launching national programs with international alliances. Currently, available prophylactic and therapeutic vaccines are expensive to be used in developing countries for vaccination programs. The recent progress in immunotherapy, biotechnology, recombinant DNA technology and molecular biology along with alternative and complementary medicinal systems have paved novel ways and valuable opportunities to design and develop effective prophylactic and therapeutic vaccines, drugs and treatment approach to counter HPV effectively. Exploration and more researches on such advances could result in the gradual reduction in the incidences of HPV cases across the world. The present review presents a current global scenario and futuristic prospects of the advanced prophylactic and therapeutic approaches against HPV along with recent patents coverage of the progress and advances in drugs, vaccines and therapeutic regimens to effectively combat HPV infections and its cancerous conditions.

Nanocarriers as phototherapeutic drug delivery system: Appraisal of three different nanosystems in an in vivo and in vitro exploratory study

The use of nanosystems as diagnosing and therapy systems is increasing each year. There are several nanosystems available and the most prominent ones are: mesoporous silica, nanoemulsion and polymeric nanoparticles. With characteristics like low toxicology, and easy-producing process they have advantages when compared with the traditional system used, as they show specific targeting, controlled release, and higher penetration. In this study we tested three different nanocarriers (polymeric nanoparticles, nanoemulsion and mesoporous silica) containing phthalocyanineas possible PDT drugs (nanodrugs). They were tested in vitro and in vivo: cells and healthy mice, respectively, in order to understand the biological behavior and reach the initial conclusions. The results in cells showed that a dose response was observed with different concentrations of the three nanocarriers. The results in animal showed that all nanosystems have potential for application in PDT, since they were able to produce a visible effect in healthy animals.

Intersurgical interval increased with use of quadrivalent human papillomavirus vaccine (Gardasil) in a pediatric patient with recurrent respiratory papillomatosis: A case report

This is a case of a 4 year old female with recalcitrant recurrent respiratory papillomatosis with decreasing intersurgical interval that had improvement in clinical course after administration of the quadrivalent HPV vaccine.

Recurrent respiratory papillomatosis: current and future perspectives

Although recurrent respiratory papillomatosis is a benign disease of the upper aerodigestive tract caused by infection with human papillomavirus, the disease process is unpredictable, ranging from mild disease and spontaneous remission to an aggressive disease with pulmonary spread and requirement for frequent surgical debulking procedures. It can present a protracted clinical course and cause potentially life-threatening compromise of the airways. Over recent decades, a number of alternative medical therapies to standard surgical treatment have been investigated, with modest outcomes overall. Currently, some additional therapies are being explored, together with novel surgical instrumentation that can help to avoid inevitable long-term stenotic complications, ultimately affecting quality of life. Hopefully, clinicians might soon be able to significantly improve the quality of treatment and outcomes for patients affected with recurrent respiratory papillomatosis, with human papillomavirus vaccination having a potentially important role.

A cell-targeted photodynamic nanomedicine strategy for head and neck cancers

Photodynamic therapy (PDT) holds great promise for the treatment of head and neck (H&N) carcinomas where repeated loco-regional therapy often becomes necessary due to the highly aggressive and recurrent nature of the cancers. While interstitial light delivery technologies are being refined for PDT of H&N and other cancers, a parallel clinically relevant research area is the formulation of photosensitizers in nanovehicles that allow systemic administration yet preferential enhanced uptake in the tumor. This approach can render dual-selectivity of PDT, by harnessing both the drug and the light delivery within the tumor. To this end, we report on a cell-targeted nanomedicine approach for the photosensitizer silicon phthalocyanine-4 (Pc 4), by packaging it within polymeric micelles that are surface-decorated with GE11-peptides to promote enhanced cell-selective binding and receptor-mediated internalization in EGFR-overexpressing H&N cancer cells. Using fluorescence spectroscopy and confocal microscopy, we demonstrate in vitro that the EGFR-targeted Pc 4-nanoformulation undergoes faster and higher uptake in EGFR-overexpressing H&N SCC-15 cells. We further demonstrate that this enhanced Pc 4 uptake results in significant cell-killing and drastically reduced post-PDT clonogenicity. Building on this in vitro data, we demonstrate that the EGFR-targeted Pc 4-nanoformulation results in significant intratumoral drug uptake and subsequent enhanced PDT response, in vivo, in SCC-15 xenografts in mice. Altogether our results show significant promise toward a cell-targeted photodynamic nanomedicine for effective treatment of H&N carcinomas.

Recurrent respiratory papillomatosis

Recurrent respiratory papillomatosis (RRP) is a rare, benign disease with no known cure. RRP is caused by infection of the upper aerodigestive tract with the human papillomavirus (HPV). Passage through the birth canal is thought to be the initial transmission event, but infection may occur in utero. HPV vaccines have helped to provide protection from cervical cancer; however, their role in the prevention of RRP is undetermined. Clinical presentation of initial symptoms of RRP may be subtle. RRP course varies, and current management focuses on surgical debulking of papillomatous lesions with or without concurrent adjuvant therapy.

Like a bolt from the blue: phthalocyanines in biomedical optics

The purpose of this review is to compile preclinical and clinical results on phthalocyanines (Pcs) as photosensitizers (PS) for Photodynamic Therapy (PDT) and contrast agents for fluorescence imaging. Indeed, Pcs are excellent candidates in these fields due to their strong absorbance in the NIR region and high chemical and photo-stability. In particular, this is mostly relevant for their in vivo activation in deeper tissular regions. However, most Pcs present two major limitations, i.e., a strong tendency to aggregate and a low water-solubility. In order to overcome these issues, both chemical tuning and pharmaceutical formulation combined with tumor targeting strategies were applied. These aspects will be developed in this review for the most extensively studied Pcs during the last 25 years, i.e., aluminium-, zinc- and silicon-based Pcs.

Photo-oxidation of cardiolipin and cytochrome c with bilayer-embedded Pc 4

Singlet oxygen, (1)O(2), is produced by absorption of red light by the phthalocyanine dye Pc 4, followed by energy transfer to dissolved triplet molecular oxygen, (3)O(2). In tissues, Pc 4 concentrates in lipid bilayers, and particularly in mitochondrial membranes, because of its positive charge. Illumination of cells and tissues with red light after uptake of Pc 4 results in cell death. The potential initial chemical steps that result in cellular dysfunction have been characterized in this study. Both unsaturated acyl chains of phospholipids and proteins are identified as targets of oxidation. Tetra-linoleoyl cardiolipin was oxidized in both liposomes and mitochondria after Pc 4-mediated (1)O(2) generation. Evidence for the formation of both mono- and bis-hydroperoxide adducts of single linoleoyl side chains is provided by ESI-MS and ESI-MS/MS. Similarly, illumination of Pc 4 in liposomes and mitochondria resulted in cytochrome c oxidation as detected by oxidation of His 26 in the peptide H(26)*KTGPNLHGLFGK, further supporting the potential use of this peptide as a biomarker for the presence of mitochondrial oxidative stress characteristic of (1)O(2) in vivo (J. Kim et al., Free Radic. Biol. Med. 44:1700-1711; 2008). These observations provide evidence that formation of lipid hydroperoxides and/or protein oxidation can be the initial chemical steps in Pc 4-mediated induction of apoptosis in photodynamic therapy.