key: cord-0830637-jvzkbhhy
authors: Joseph, Betsy; Prasanth, CS
title: Can Photodynamic therapy be repurposed to treat oral lesions of COVID-19?
date: 2021-01-08
journal: Photodiagnosis Photodyn Ther
DOI: 10.1016/j.pdpdt.2021.102175
sha: 5e9d09439d4409fcb09893927b2a6c960c820697
doc_id: 830637
cord_uid: jvzkbhhy

• Dental health is one of the worst affected domains due to this pandemic. • Numerous oral manifestations of COVID-19 are reported. • There is an urgent need to develop new treatment modalities to treat these. • We hypothesis that PDT may be repurposed to treat oral lesions of COVID-19. • The purpose of this paper is to suggest the prospect of using PDT for the treatment of oral lesions in COVID-19 patients. • There is a need to conduct controlled clinical trials using PDT in the oral cavity to evaluate its effectivity against SARS-CoV-2. • PDT it can be used not only in symptomatic patients to relieve pain but also in asymptomatic patients' oral cavity, periodontal pockets, and saliva. • Photodynamic therapy can be repurposed to treat oral lesions of COVID-19.

We read with great interest the recent article published by Svyatchenko et al., 2020 , describing the antiviral potential of photodynamic therapy (PDT) using Methylene Blue and Radachlorin to inactivate and Inhibit SARS-CoV-2 In Vitro. The authors have presented an exciting finding which is very relevant during this COVID-19 pandemic. We want to discuss a novel concept of PDT in treating oral lesions in COVID-19 patients.

Dental health is one of the worst affected domains due to this pandemic. Numerous oral manifestations of COVID-19 are reported, such as ulcer of tongue and mouth, fissured or depapillated tongue, halitosis, vesiculobullous lesions, recurrent herpes simplex, candidiasis, and spontaneous bleeding (Iranmanesh et al., 2020; Carreras-Presas et al., 2020; Santos et al., 2020). Among these, more than half (68%) of the oral lesions were symptomatic when 35 cases with COVID-19 were assessed (Iranmanesh et al., 2020) . Various treatment modalities were used to manage these oral lesions (Iranmanesh et al., 2020) . However, many of these drugs have drawbacks, such as the development of resistance and exuberant cost. Therefore, there is an urgent need to identify or develop new treatment modalities to prevent and treat oral lesions in these patients.

In the past, PDT has been used for treating many bacterial, fungal, and viral lesions, including oral vesiculobullous lesions. The authors of this paper themselves have publications, including clinical trials (Betsy et al., 2014; Betsy et al., 2016; Joseph et al., 2017 ) that use PDT in periodontal disease. However, during COVID-19 times, none of the studies so far explore PDT's potential in managing oral lesions. Therefore, we hypothesis that PDT may be repurposed to treat oral lesions of COVID-19.

The purpose of this paper is to suggest the prospect of using PDT for the treatment of oral lesions in COVID-19 patients. PDT is a potential antiviral tool that could prove a highly effective method of preventing and treating COVID-19. An evidence-based approach supports our theory as in the past, PDT not only has inactivated bacteria, viruses, and fungi directly but also attenuates the organism indirectly by stimulating the immune system.

PDT has been found to combat secondary infections in COVID-19 patients and can also be a complementary treatment for decreasing the viral and bacterial load in the patient's saliva and oral cavity. Hence, we hypothesize that PDT treats oral vesicular lesions and ulcers following the local application of porphyrin-based PSs onto the vesicular lesions and ulcers. Moreover, PS molecules may act as a 'decoy' (Li et al., 2020) such that SARS-CoV-2 virions would attach to PS molecules instead of healthy oral tissue or attack healthy hemoglobin (Kipshidze et al., 2020) even without the need for photoactivation.

The susceptibility of SARS-CoV-2 to PDT in humans can be seen in recent literature (Almeida et al. 2020) . Encouraging in vitro results show that PSs Methylene blue (MB) and Radachlorin at very low concentrations (100-1000 times lower than usual) when activated by 662 nm light caused inhibition of SARS-CoV-2 (Svyatchenko et al., 2020) . Recent evidence shows that MB has demonstrated virucidal activity when incubated with SARS-CoV-2 at low micromolar concentrations. Furthermore, MB has been shown to inhibit the SARS-CoV-2 spike protein and its ACE2 receptor, which is crucial in inactivating the virus (Verdecchia et al., 2020).

Despite of this, there is no strong evidence yet regarding the inactivation of SARS-CoV-2 in the oral cavity by using PDT in vivo. Hence, we recommend the need to conduct controlled clinical trials using PDT in the oral cavity to evaluate its effectivity against SARS-CoV-2. We believe that due to the antiviral, immunostimulatory, and immunosuppressive effects of PDT, it can be used not only in symptomatic patients to relieve pain but also in asymptomatic patients' oral cavity, periodontal pockets, and saliva to control the outbreak and avoid oral contact infection.

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