In vitro effect of artemether-loaded nanostructured lipid carrier (NLC) on Leishmania infantum

Artemisinin: An Anti-Leishmania Drug that Targets the Leishmania Parasite and Activates Apoptosis of Infected Cells

Leishmaniasis is a relevant disease worldwide due to its presence in many countries and an estimated prevalence of 10 million people. The causative agent of this disease is the obligate intracellular parasite Leishmania which can infect different cell types. Part of its success depends on its ability to evade host defense mechanisms such as apoptosis. Apoptosis is a finely programmed process of cell death in which cells silently dismantle and actively participate in several processes such as immune response, differentiation, and cell growth. Leishmania has the ability to delay its initiation to persist in the cell. It has been well documented that different Leishmania species target different pathways that lead to apoptosis of cells such as macrophages, neutrophils, and dendritic cells. In many cases, the observed anti-apoptotic effect has been associated with a significant reduction in caspase-3 activity. Leishmania has also been shown to target several pathways involved in apoptosis such as MAPK, PI3K/Akt, and the antiapoptotic protein Bcl-xL. Understanding the strategies used by Leishmania to subvert the defense mechanisms of host cells, particularly apoptosis, is very relevant for the development of therapies and vaccines. In recent years, the drug artemisinin has been shown to be effective against several parasitic diseases. Its role against Leishmania may be promising. In this review, we provide important aspects of the disease, the strategies used by the parasite to suppress apoptosis, and the role of artemisinin in Leishmania infection.

Revolutionizing Leishmaniasis Treatment with Cutting Edge Drug Delivery Systems and Nanovaccines: An Updated Review

Leishmaniasis, one of the most overlooked tropical diseases, is a life-threatening illness caused by the parasite Leishmania donovani that is prevalent in underdeveloped nations. Over 350 million individuals in more than 90 different nations worldwide are at risk of contracting the disease, which has a current fatality rate of 50 000 mortalities each year. The administration of liposomal Amp B, pentavalent antimonials, and miltefosine are still considered integral components of the chemotherapy regimen. Antileishmanial medications fail to treat leishmaniasis because of their numerous drawbacks. These include inadequate effectiveness, toxicity, undesired side effects, drug resistance, treatment duration, and cost. Consequently, there is a need to overcome the limitations of conventional therapeutics. Nanotechnology has demonstrated promising outcomes in addressing these issues because of its small size and distinctive characteristics, such as enhanced bioavailability, lower toxicity, biodegradability, and targeted drug delivery. This review is an effort to highlight the recent progress in various nanodrug delivery systems (nDDSs) over the past five years for treating leishmaniasis. Although the preclinical outcomes of nDDSs have shown promising treatment for leishmaniasis, further research is needed for their clinical translation. Advancement in three primary priority domains─molecular diagnostics, clinical investigation, and knowledge dissemination and standardization─is imperative to propel the leishmaniasis field toward translational outcomes.

Preparation and characterization of artemether-loaded niosomes in Leishmania major-induced cutaneous leishmaniasis

Cutaneous leishmaniasis is the most prevalent form of leishmaniasis worldwide. Although various anti-leishmanial regimens have been considered, due to the lack of efficacy or occurrence of adverse reactions, design and development of novel topical delivery systems would be essential. This study aimed to prepare artemether (ART)-loaded niosomes and evaluate their anti-leishmanial effects against Leishmania major. ART-loaded niosomes were prepared through the thin-film hydration technique and characterized in terms of particle size, zeta potential, morphology, differential scanning calorimetry, drug loading, and drug release. Furthermore, anti-leishmanial effect of the preparation was assessed in vitro and in vivo. The prepared ART-loaded niosomes were spherical with an average diameter of about 100 and 300 nm with high encapsulation efficiencies of > 99%. The results of in vitro cytotoxicity revealed that ART-loaded niosomes had significantly higher anti-leishmanial activity, lower general toxicity, and higher selectivity index (SI). Half-maximal inhibitory concentration (IC50) values of ART, ART-loaded niosomes, and liposomal amphotericin B were 39.09, 15.12, and 20 µg/mL, respectively. Also, according to the in vivo study results, ART-loaded niosomes with an average size of 300 nm showed the highest anti-leishmanial effects in animal studies. ART-loaded niosomes would be promising topical drug delivery system for the management of cutaneous leishmaniasis.

Curcumin-loaded nanostructured systems for treatment of leishmaniasis: a review

Leishmaniasis is a neglected tropical disease that has affected more than 350 million people worldwide and can manifest itself in three different forms: cutaneous, mucocutaneous, or visceral. Furthermore, the current treatment options have drawbacks which compromise efficacy and patient compliance. To face this global health concern, new alternatives for the treatment of leishmaniasis have been explored. Curcumin, a polyphenol obtained from the rhizome of turmeric, exhibits leishmanicidal activity against different species of Leishmania spp. Although its mechanism of action has not yet been fully elucidated, its leishmanicidal potential may be associated with its antioxidant and anti-inflammatory properties. However, it has limitations that compromise its clinical use. Conversely, nanotechnology has been used as a tool for solving biopharmaceutical challenges associated with drugs, such as curcumin. From a drug delivery standpoint, nanocarriers (1-1000 nm) can improve stability, increase solubility, promote intracellular delivery, and increase biological activity. Thus, this review offers a deep look into curcumin-loaded nanocarriers intended for the treatment of leishmaniasis.

Investigation of antileishmanial activities of CaO nanoparticles on L. tropica and L. infantum parasites, in vitro

Stibogluconate sodium and meglumine antimoniate are the main antimonials utilised as the primary treatment option for leishmaniasis. However, have a number of side effects that limit their use. Development of nanoparticles (NPs) use in biological research and remarkable antimicrobial effects and unique optical and structural properties of CaO NPs have motivated this study to evaluated the effect of different times/dilutions of CaO NPs on Leishmania tropica and Leishmania infantum. To evaluate the antileishmanial activity of CaO NPs, the cytotoxic effect of CaO NPs against L. tropica and L. infantum amastigotes, promastigotes, as well as macrophages, was evaluated using counting and MTT assay after adding different concentrations of CaO nanoparticles (800-6.25 μg/ml) to the parasite culture. The possible apoptosis by CaO NPs were evaluated via flow cytometry assay. The XRD-pattern related to CaO nanoparticles indicating the cubic phase structures. According the effects of nanoparticle on promastigotes the IC50 values of CaO nanoparticles within 72 h were 19.81 μg/ml for L. tropica and 22.57 μg/ml for L. infantum. The percentage of the normal, apoptotic, and necrotic cells was estimated to be 82.6%, 14.81%, and 2.69% for L. tropica, and 73.6%, 23.89%, and 2.58% for L. infantum, respectively. Our results showed acceptable in vitro activity level of CaO NPs against L. tropica and L. infantum promastigotes as well as intracellular amastigotes. CaO NPs were more effective against L. infantum compared to L. tropica in vitro study.

Cytotoxic screening and in vitro effect of sodium chlorite against Leishmania major promastigotes

Cutaneous leishmaniasis (CL) is one of the most important parasitic diseases in the world. Despite the existence of many therapeutic strategies, the treatment of this infection still faces problems. Sodium chlorite as an antimicrobial agent has been shown to have acceptable tissue regenerative and wound healing properties. Therefore, the present study aimed to analyze the in vitro effects of different concentrations of sodium chlorite on Leishmania major promastigotes and macrophage cells. The inhibitory and toxicity effect of various concentrations (0.0035, - 1.8 mg/ml) of sodium chlorite on the standard Iranian strain of L. major promastigotes were evaluated via counting the cells and flow cytometry. Furthermore, cytotoxicity on promastigotes and J774 macrophage cell line were performed by MTT assay. The results of the inhibitory test demonstrated that sodium chlorite had dose-dependent, anti-leishmanial activities. The half-maximal inhibitory concentration (IC50) for promastigotes and J774 cells by cytotoxicity test was detected at 0.17 mg/ml and 0.08 mg/ml after 48 h respectively. Flow cytometry results showed that 27.34% death of promastigotes was observed in 0.0035 mg/ml of sodium chlorite and 78.12% in 1.8 mg/ml. The results of the present study showed that sodium chlorite could be used as an effective treatment for CL, especially in cases resistant to treatment with pentavalent compounds. However, the toxicity of this substance in high concentrations should be considered in clinical setting.

Challenges and Tools for In Vitro Leishmania Exploratory Screening in the Drug Development Process: An Updated Review

Leishmaniases are a group of vector-borne diseases caused by infection with the protozoan parasites Leishmania spp. Some of them, such as Mediterranean visceral leishmaniasis, are zoonotic diseases transmitted from vertebrate to vertebrate by a hematophagous insect, the sand fly. As there is an endemic in more than 90 countries worldwide, this complex and major health problem has different clinical forms depending on the parasite species involved, with the visceral form being the most worrying since it is fatal when left untreated. Nevertheless, currently available antileishmanial therapies are significantly limited (low efficacy, toxicity, adverse side effects, drug-resistance, length of treatment, and cost), so there is an urgent need to discover new compounds with antileishmanial activity, which are ideally inexpensive and orally administrable with few side effects and a novel mechanism of action. Therefore, various powerful approaches were recently applied in many interesting antileishmanial drug development programs. The objective of this review is to focus on the very first step in developing a potential drug and to identify the exploratory methods currently used to screen in vitro hit compounds and the challenges involved, particularly in terms of harmonizing the results of work carried out by different research teams. This review also aims to identify innovative screening tools and methods for more extensive use in the drug development process.