Leishmania tropica successfully treated with photodynamic therapy

Efficacy of photodynamic therapy in cutaneous leishmaniasis: A systematic review

OBJECTIVE

To systematically review the efficacy of photodynamic therapy (PDT) in the treatment of cutaneous leishmaniasis (CL).

METHODS

PubMed, Embase and Cochrane Library databases were searched for articles published by November 16, 2022, with no time restrictions. 'Cutaneous leishmaniasis' and 'photodynamic therapy' were searched using predefined search strings.

INCLUSION CRITERIA

(i) Randomized control trials; (ii) controlled clinical trials; (iii) case series; (iv) case reports; (v) participants were humans; (vi) clinical diagnosis was CL; (vii) treatment method used was PDT; and (viii) articles published in English.

RESULTS

In total, 303 articles were identified, including 14 papers meeting the criteria. The number of patients in each study ranged from 1 to 60 and the age ranged from 1 to 82 years. Aminolevulinic acid and methyl aminolevulinate were used as photosensitizers. Red light and sunlight were used as light sources. All reported satisfactory clinical effects. Side effects of treatment included burning sensation, pain and pigmentation after treatment. However, they were tolerable and temporary. The follow-up time ranged between 9 weeks and 24 months. A total of two patients recurred, but one did not recur after another round of PDT during the follow-up period.

CONCLUSIONS

The present study suggests that PDT is a safe and effective method for the treatment of CL, with tolerable side effects and good efficacy. As an alternative treatment method of CL, PDT has great potential. However, to verify the efficacy and specific mechanism of PDT for the optimal treatment strategy of CL, further research with larger sample sizes and longer follow-up times are needed.

Alternative Non-Drug Treatment Options of the Most Neglected Parasitic Disease Cutaneous Leishmaniasis: A Narrative Review

With more than 12 million cases worldwide, leishmaniasis is one of the top 10 neglected tropical diseases. According to the WHO, there are approximately 2 million new cases each year in foci in around 90 countries, of which 1.5 million are cutaneous leishmaniasis (CL). Cutaneous leishmaniasis (CL) is a complex cutaneous condition that is caused by a variety of Leishmania species, including L. (Leishmania) major, L. (L) tropica, L. (L) aethiopica, L. (L) mexicana, L. (Viannia) braziliensis, and L. (L) amazonensis. The disease imposes a significant burden on those who are affected since it typically results in disfiguring scars and extreme social stigma. There are no vaccines or preventive treatments available, and chemotherapeutic medications, including antimonials, amphotericin B, miltefosine, paromomycin, pentamidine, and antifungal medications, have a high price tag, a significant risk of developing drug resistance, and a variety of systemic toxicities. To work around these limitations, researchers are continuously looking for brand-new medications and other forms of therapy. To avoid toxicity with systemic medication use, high cure rates have been observed using local therapy techniques such as cryotherapy, photodynamic therapy, and thermotherapy, in addition to some forms of traditional therapies, including leech and cauterization therapies. These CL therapeutic strategies are emphasized and assessed in this review to help with the process of locating the appropriate species-specific medicines with fewer side effects, lower costs, and elevated cure rates.

Evaluation of the Photodynamic Therapy with Curcumin on L. braziliensis and L. major Amastigotes

Cutaneous leishmaniasis (CL) is a neglected disease prevalent in tropical countries with the ability to cause skin lesions. Photodynamic therapy (PDT) represents a specific and topical option for the treatment of these lesions. This study evaluated the response of macrophages infected with L. braziliensis and L. major to PDT with curcumin. Curcumin concentrations were evaluated in serial dilutions from 500.0 to 7.8 µg/mL using LED (λ = 450 ± 5 nm), with a light dose of 10 J/cm². The Trypan blue viability test, ultrastructural analysis by scanning electron microscopy (SEM), mitochondrial polarity by Rhodamine 123 (Rho 123), curcumin internalization by confocal microscopy, and counting of the recovered parasites after the PDT treatment were performed. The lowest concentrations of curcumin (15.6 and 7.8 µg/mL) presented photodynamic inactivation. Cell destruction and internalization of curcumin in both macrophages and intracellular parasites were observed in microscopy techniques. In addition, an increase in mitochondrial membrane polarity and a decrease in the number of parasites recovered was observed in the PDT groups. This study indicates that PDT with curcumin has the potential to inactivate infected macrophages and might act as a basis for future in vivo studies using the parameters herein discussed.

Photodynamic effect of palladium porphyrin derived from cashew nut shell liquid against promastigote forms of Leishmania braziliensis

Cutaneous leishmaniasis (CL) is a neglected tropical disease (NTD), endemic mainly in low-income countries that lack adequate basic health care. The emergence of resistant parasites to pentavalent antimonials has led to the search for new treatments for CL. Photodynamic therapy (PDT) is a promising non-invasive and less toxic alternative for the treatment of CL. The present work describes the synthesis, characterization and photodynamic effect against CL of a new metalloporphyrin Pd (II) meso-tetra[4-(2-(3-n-pentadecylphenoxy)ethoxy]phenylporphyrin (PdP) derived from the cashew nut shell liquid (CNSL). The PdP complex presented a singlet oxygen quantum yield of 0.49, favoring a type II photochemical reaction. The results of the photodynamic experiment carried out with PdP on the promastigote forms of Leishmania braziliensis indicated a mortality percentage of 70 % of the cells when compared to the control after exposure to blue light (λ = 420 nm). Besides this, the metalloporphyrin PdP did not show considerable toxicity to macrophages, indicating the cell viability of the compound. Therefore, this metalloporphyrin derived from biomass represents an interesting alternative as a potential therapeutic drug for the treatment of CL through PDT, especially for patients with intolerance to the chemotherapeutic drugs currently available.