Current treatment for cutaneous leishmaniasis: a review

Exploring microalgal and cyanobacterial metabolites with antiprotozoal activity against Leishmania and Trypanosoma parasites

Neglected tropical diseases (NTD) like Leishmaniasis and trypanosomiasis affect millions of people annually, while currently used antiprotozoal drugs have serious side effects. Drug research based on natural products has shown that microalgae and cyanobacteria are a promising platform of biochemically active compounds with antiprotozoal activity. These unicellular photosynthetic organisms are rich in polyunsaturated fatty acids, pigments including phycocyanin, chlorophylls and carotenoids, polyphenols, bioactive peptides, terpenes, alkaloids, which have proven antioxidant, antimicrobial, antiviral, antiplasmodial and antiprotozoal properties. This review provides up-to-date information regarding ongoing studies on substances synthesized by microalgae and cyanobacteria with notable activity against Leishmania spp., Trypanosoma cruzi, and Trypanosoma brucei, the causative agents of Leishmaniasis, Chagas disease, and human African trypanosomiasis, respectively. Extracts of several freshwater or marine microalgae have been tested on different strains of Leishmania and Trypanosoma parasites. For instance, ethanolic extract of Chlamydomonas reinhardtii and Tetraselmis suecica have biological activity against T. cruzi, due to their high content of carotenoids, chlorophylls, phenolic compounds and flavonoids that are associated with trypanocidal activity. Halophilic Dunaliella salina showed moderate antileishmanial activity that may be attributed to the high β-carotene content in this microalga. Peptides such as almiramides, dragonamides, and herbamide that are biosynthesized by marine cyanobacteria Lyngbya majuscula were found to have increased activity in micromolar scale IC50 against L. donovani, T. Cruzi, and T. brucei parasites. The cyanobacterial peptides symplocamide and venturamide isolated from Symploca and Oscillatoria species, respectively, and the alkaloid nostocarbonile isolated from Nostoc have shown promising antiprotozoal properties and are being explored for pharmaceutical and medicinal purposes. The discovery of new molecules from microalgae and cyanobacteria with therapeutic potential against Leishmaniasis and trypanosomiasis may address an urgent medical need: effective and safe treatments of NTDs.

Human Cutaneous Leishmaniasis in North Africa and Its Threats to Public Health: A Statistical Study Focused on Djelfa (Algeria)

Cutaneous leishmaniasis, the most common form of leishmaniasis, causes long-term skin lesions on exposed areas of the skin. It is caused by a protozoan parasite belonging to the genus Leishmania and is transmitted via infected phlebotomine sand flies. In North Africa, particularly Algeria, the disease represents a major public health problem. This retrospective study, which focuses on the agropastoral region of Djelfa (central Algeria) during a period of 16 years, from 2006 to 2021, is part of the surveillance of cutaneous leishmaniasis to identify the key factors favouring its probable spread. The analyzed data reveal that this disease is more prevalent in male patients (53.60%) and is highly widespread in this vast area of 66,415 km2 with a total of 3864 CL cases, reaching a peak of 1407 cases in 2006. Statistically, the Pearson correlation validated by the p-value shows, in an original and sometimes unexpected way, that certain factors, such as temperature linked to climate change, are playing a significant role in the probable spread of the disease in Djelfa and its surrounding regions. The concentration of the population in some specific rural areas with limited or nonexistent access to public health services is another potential factor in disease transmission. The results were highlighted by a significant correlation coefficient (r=0.66) with a p-value less than 0.01. While there is currently no vaccine or prophylactic drug available, our research represents a preliminary approach that addresses various epidemiological aspects of the disease. This paves the way for a proactive preventive strategy involving the control of vector-borne diseases.

First-Row Transition 7-Oxo-5-phenyl-1,2,4-triazolo[1,5-a]pyrimidine Metal Complexes: Antiparasitic Activity and Release Studies

Leishmaniasis and Chagas disease are still considered neglected illnesses due to the lack of investment in research, despite the fact that almost one million new cases are reported every year. Four 7-oxo-5-phenyl-1,2,4-triazolo[1,5-a]pyrimidine (HftpO) first-row transition complexes (Cu, Co, Ni, Zn) have been studied for the first time in vitro against five different species of Leishmania spp. (L. infantum, L. braziliensis, L. donovani, L. peruviana and L. mexicana) as well as Trypanosoma cruzi, showing higher efficacy than the reference commercial drugs. UV and luminescence properties were also evaluated. As a proof of concept, anchoring of a model high-effective-metal complex as an antiparasitic agent on silica nanoparticles was carried out for the first time, and drug-release behaviour was evaluated, assessing this new approach for drug vehiculation.

Efficacy of fibroblast transplantation in the healing of cutaneous leishmaniasis scar: A case report

Autologous fibroblast transplantation has been proven to be a promising method in wound healing with no side effects. This is the first study aimed to determine the efficacy and safety of autologous fibroblast cell injection to the atrophic scar caused by cutaneous leishmaniasis as an endemic disease in many middle-eastern countries. It causes chronic skin lesions and permanently disfiguring scars. Autologous fibroblasts were obtained from the patient's ear skin and were injected intradermally twice at 2-month intervals. Outcomes were measured using ultrasonography, VisioFace, and Cutometer. No adverse reaction was observed. The results showed improvements in epidermal thickness and density, melanin level, and skin lightening. Moreover, the skin elasticity in the scar area increased after the second transplantation. No improvement was observed in dermal thickness and density. A longer follow-up with more patients is recommended to investigate the effectiveness of fibroblast transplantation better.

Antileishmanial activity of tetra-cationic porphyrins with peripheral Pt(II) and Pd(II) complexes mediated by photodynamic therapy approaches

Leishmaniasis is a seriously neglected disease that impacts more than one billion people in endemic areas of the globe. Several drawbacks are associated with the currently existing drugs for the treatment as low effectiveness, toxicity, and the emergence of resistant strains that demonstrates the importance of looking for novel therapeutic alternatives. Photodynamic therapy (PDT) is a promising novel alternative for cutaneous leishmaniasis treatment because its topical application avoids potential side effects generally associated with oral/parenteral application. A light-sensitive compound known as photosensitizer (PS) interacts with light and molecular oxygen to generate reactive oxygen species (ROS), which promote cell death by oxidative stress through PDT approaches. Here, for the first time, we demonstrate the antileishmanial effect of tetra-cationic porphyrins with peripheral Pt(II)- and Pd(II)-polypyridyl complexes using PDT. The isomeric tetra-cationic porphyrins in the meta positions, 3-PtTPyP, and 3-PdTPyP, exhibited the highest antiparasitic activity against promastigote (IC_50-pro = 41.8 nM and 46.1 nM, respectively) and intracellular amastigote forms (IC_50-ama = 27.6 nM and 38.8 nM, respectively) of L. amazonensis under white light irradiation (72 J cm^-2) with high selectivity (SI > 50) for both forms of parasites regarding mammalian cells. In addition, these PS induced the cell death of parasites principally by a necrotic process in the presence of white light by mitochondrial and acidic compartments accumulation. This study showed that porphyrins 3-PtTPyP and 3-PdTPyP displayed a promising antileishmanial-PDT activity with potential application for cutaneous leishmaniasis treatment.

The novel treatments based on tissue engineering, cell therapy and nanotechnology for cutaneous leishmaniasis

Cutaneous leishmaniasis (CL) is a global public health issue. Conventional treatments have substantial costs, side effects, and parasite resistance. Due to easy application and inexpensive cost, topical treatment is the optimal approach for CL. It could be used alone or with systemic treatments. Electrospun fibers as drug release systems in treating skin lesions have various advantages such as adjustable drug release rate, maintaining appropriate humidity and temperature, gas exchange, plasticity at the lesion site, similarity with the skin extracellular matrix (ECM) and drug delivery with high efficiency. Hydrogels are valuable scaffolds in the treatment of skin lesions. The important features of hydrogels include preserving unstable drugs from degradation, absorption of wound secretions, high biocompatibility, improving the re-epithelialization of the wound and preventing the formation of scars. One of the issues in local drug delivery systems for the skin is the low permeability of drugs in the skin. Polymeric scaffolds that are designed as microneedle patches can penetrate the skin and overcome this challenge. Also, drug delivery using nanocarriers increases the effectiveness of drugs in lower and more tolerable doses and reduces the toxicity of drugs. The application of cell therapy in the treatment of parasitic and infectious diseases has been widely investigated. The complexity of leishmaniasis treatment requires identifying new treatment options like cell therapy to overcome the disease. Topics investigated in this study include drug delivery systems based on tissue engineering scaffolds, nanotechnology and cell therapy-based studies to reduce the complications of CL.

HAS 1: A natural product from soil-isolated Streptomyces species with potent activity against cutaneous leishmaniasis caused by Leishmania tropica

Cutaneous Leishmaniasis (CL) is a neglected tropical disease, classified by the World Health Organization (WHO) as one of the most unrestrained diseases. The Syrian war and the significant displacement of refugees aggravated the spread of this ailment into several neighboring countries in the Eastern Mediterranean Region (EMR). In Syria, Leishmania tropica is identified as one of the most aggressive and endemic identified species, causing localized or generalized lesions, often chronic or relapsing. Pentavalent antimonial drugs are currently used as first line treatment against CL. Nonetheless, these drugs exhibit several limitations, including the repetitive painful injections, high cost, poor availability, and mainly systemic toxicity. Besides, the emergence of acquired parasitic resistance hinders their potency, stressing the need for new therapies to combat CL. Natural products (NPs) epitomize a valuable source in drug discovery. NPs are secondary metabolites (SMs) produced by plants, sponges, or a wide variety of organisms, including environmental microorganisms. The EMR is characterized by its immense biodiversity, yet it remains a relatively untapped area in drug discovery. NPs of the region were explored over the last 2 decades, but their discoveries lack biogeographical diversity and are limited to the Red Sea. Here, we isolated previously uncultured environmental soil-dwelling Streptomyces sp. HAS1, from Hasbaya region in southeast Lebanon. When fermented in one of our production media named INA, HAS1 produced a crude extract with significant potency against a clinical Leishmania tropica isolate. Using bio-guided fractionation, the bioactive compound was purified and the structure was elucidated by NMR and LC-HRMS. Our findings establish NPs as strong candidates for treating Leishmania tropica and further dwells on the importance of these natural sources to combat microbial infections.

Synthesis of aminochalcones and in silico evaluation of their antiparasitic potential against Leishmania

Leishmaniasis disease is a serious public health problem. This disease reaches about 10 to 12 million people, and 20-30 thousand people die yearly. The disease treatment is realized through pentavalent antimonial and glucantime. However, some studies indicated that these drugs presented high toxicity and cost. Therefore, it is urgent the search for new drugs that may combat this disease and are less toxic. This work analyzed for the first time the interaction potential of (E)-1-(4-aminophenyl)-3-phenylprop-2-en-1-one (C1), (E)-1-(4-aminophenyl)-3-(4-methoxyphenyl)-prop-2-en-1-one (C4), (E)-1-(4-aminophenyl)-3-(4ethoxyphenyl)-prop-2-en-1-one (C9) chalcones through in silico approach. The molecular docking and the molecular electrostatic potential results indicated that the chalcones analyzed presented a strong interaction with the Leishmania major receptor, with affinity energy similar to the ligand co-crystallized. Besides, the interaction potential energy analysis from molecular dynamics simulations indicated the C9 ligand interacted more strongly than the 4-bromo-2,6-dichloro-N-(1,3,5-trimethyl-1H-pyrazolyl) benzenesulfonamide ligand with the Leishmania major receptor, especially for the Phe 88, Tyr 217 and His 219 residues. Therefore, the C9 chalcone might potentially treat Leishmaniasis disease.Communicated by Ramaswamy H. Sarma.

Thiazolidine derivatives: In vitro toxicity assessment against promastigote and amastigote forms of Leishmania infantum and ultrastructural study

Neglected diseases, such as Leishmaniasis, constitute a group of communicable diseases that occur mainly in tropical countries. Considered a public health problem with limited treatment. Therefore, there is a need for new therapies. In this sense, our proposal was to evaluate in vitro two series of thiazolidine compounds (7a-7e and 8a-8e) against Leishmania infantum. We performed in vitro evaluations through macrophage cytotoxicity assays (J774) and nitric oxide production, activity against promastigotes and amastigotes, as well as ultrastructural analyzes in promastigotes. In the evaluation of cytotoxicity, the thiazolidine compounds presented CC₅₀ values between 8.52 and 126.83 μM. Regarding the evaluation against the promastigote forms, the IC₅₀ values ranged between 0.42 and 142.43 μM. Compound 7a was the most promising, as it had the lowest IC₅₀. The parasites treated with compound 7a showed several changes, such as cell body shrinkage, shortening and loss of the flagellum, intense mitochondrial edema and cytoplasmic vacuolization, leading the parasite to cell inviability. In assays against the amastigote forms, the compound showed a low IC₅₀ (0.65 μM). These results indicate that compound 7a was efficient for both evolutionary forms of the parasite. In silico studies suggest that the compound has good oral bioavailability. These results show that compound 7a is a potential drug candidate for the treatment of Leishmaniasis.

Evaluating the Efficacy of Combined Intralesional Sodium Stibogluconate Plus Topical Imiquimod on Healing and Risk of Scarring of Cutaneous Leishmaniasis: A Case-Control Study

Background: A combination treatment of cutaneous leishmaniasis (CL) that hastens the healing and reduces the chance of scarring, especially in aesthetically receptive sites, is required.

Objectives: To evaluate if a combination of intralesional sodium stibogluconate (SSG) injection and topical imiquimod 5% cream (IMI) accelerates healing and improves the quality of scars from CL.

Patients and Methods: A prospective, placebo-controlled, randomized clinical trial was conducted at Basrah Teaching Hospital, Basrah, southern Iraq from 2017 to 2019 on a cohort of patients with CL. Eligible patients were injected intralesionally with sodium stibogluconate (SSG) weekly for six weeks and randomized to receive either topical imiquimod 5% cream (IMI group) or topical emollient cream (placebo group). The healing rate and scar quality were assessed at week six.

Results: One hundred twenty-one patients completed the trial (66 [55%] males, mean age SD: 34.1 years). The clinical healing rate was significantly higher in the IMI group than in the placebo group (94% versus 74%, p <0.05). A high rate of scars was noticed in both groups (66.6% in the IMI group and 91.2% in the placebo group). However, superficial non-atrophic scars were more frequent in the IMI group (40% versus 26%), while deep atrophic scars were more evident in the placebo group than in the IMI group (65.2% versus 26.6%, p<0.05).

Conclusions: Combined intralesional SSG plus topical imiquimod was beneficial in accelerating CL healing and improving scar quality, and should be considered when CL is located in aesthetically sensitive areas.

Metagenomic Analysis Identifying a Rare Leishmania Infection in an Adult With AIDS

Leishmania belongs to a genus of the protozoan parasites that causes leishmaniasis, and includes cutaneous leishmaniasis (CL) and visceral leishmaniasis (VL). In this case, Leishmania amastigotes were found on cytomorphology examination of the bone marrow specimen, followed by 1,076 Leishmania donovani reads using metagenomic next generation sequencing (mNGS). Since being definitely diagnosed with VL/HIV coinfection, the patient was treated with liposomal amphotericin B as the parasite-resistant therapy and was discharged after clinical cure. But nearly a year later, on the mNGS follow-up, L. donovani was detected in the patient’s blood plasma specimen with 941 reads, suggesting that a relapse of leishmaniasis had occurred. These results indicate that leishmaniasis still exists in China and may represent a public health concern. This case could be helpful in the differential diagnosis of leishmaniasis, and for determining disease progression, prevention, and control of vectors and reservoir hosts.

A machine learning-based system for detecting leishmaniasis in microscopic images

Background

Leishmaniasis, a disease caused by a protozoan, causes numerous deaths in humans each year. After malaria, leishmaniasis is known to be the deadliest parasitic disease globally. Direct visual detection of leishmania parasite through microscopy is the frequent method for diagnosis of this disease. However, this method is time-consuming and subject to errors. This study was aimed to develop an artificial intelligence-based algorithm for automatic diagnosis of leishmaniasis.

Methods

We used the Viola-Jones algorithm to develop a leishmania parasite detection system. The algorithm includes three procedures: feature extraction, integral image creation, and classification. Haar-like features are used as features. An integral image was used to represent an abstract of the image that significantly speeds up the algorithm. The adaBoost technique was used to select the discriminate features and to train the classifier.

Results

A 65% recall and 50% precision was concluded in the detection of macrophages infected with the leishmania parasite. Also, these numbers were 52% and 71%, respectively, related to amastigotes outside of macrophages.

Conclusion

The developed system is accurate, fast, easy to use, and cost-effective. Therefore, artificial intelligence might be used as an alternative for the current leishmanial diagnosis methods.

New insights into the mechanism of action of the cyclopalladated complex - CP2 in Leishmania: Calcium Dysregulation, Mitochondrial Dysfunction and Cell Death

The current treatment of leishmaniasis is based on few drugs that present several drawbacks such as high toxicity, difficult administration route, and low efficacy. These disadvantages raise the necessity to develop novel antileishmanial compounds allied to a comprehensive understanding of their mechanisms of action. Here, we elucidate the probably mechanism of action of the antileishmanial binuclear cyclopalladated complex [Pd(dmba)(μ-N₃)]₂ (CP2) in Leishmania amazonensis. CP2 causes oxidative stress in the parasite resulting in disruption of mitochondrial Ca²⁺ homeostasis, cell cycle arrest at S-phase, increasing the ROS production and overexpression of stress-related and cell detoxification proteins, collapsing the Leishmania mitochondrial membrane potential and promotes apoptotic-like features in promastigotes leading to necrosis or directs programmed cell death (PCD)-committed cells toward necrotic-like destruction. Moreover, CP2 is able to reduce the parasite load in both liver and spleen in Leishmania infantum-infected hamsters when treated for 15 days with 1.5 mg/Kg/day CP2, expanding its potential application in addition to the already known effectiveness on cutaneous leishmaniasis for the treatment of visceral leishmaniasis, showing the broad spectrum of action of this cyclopalladated complex. The data herein presented bring new insights into the CP2 molecular mechanisms of action, assisting to promote its rational modification to improve both safety and efficacy.

Antileishmanial Activity of Ziziphus spina-christi Leaves Extract and Its Possible Cellular Mechanisms

This experimental investigation was designed to assess the in vitro and in vivo antileishmanial effects of Z. spina-christi methanolic extract (ZSCME) and also aims to assess some of the antileishmanial mechanisms such as the NO production, apoptosis, and plasma membrane permeability. We assessed the in vitro leishmanicidal effects of ZSCME (10–200 µg/mL) against intracellular amastigote stage of the Leishmania major (MRHO/IR/75/ER) and, then, in vivo examined male BALB/c mice infected by L. major. In addition, the rate of infectivity, Caspase 3 activity, nitric oxide (NO) production, the plasma membrane permeability, and the cytotoxic effects of ZSCME were studied. The primary phytochemical analysis of ZSCME revealed the existence of high amounts of flavonoids, tannins, glycosides, alkaloids, and saponin in this plant. The findings exhibited that ZSCME meaningfully (p < 0.001) reduced the viability of amastigotes of L. major, whereas it prompted the creation and release of NO, apoptosis, and the plasma membrane permeability (p < 0.05) and indicated no cytotoxicity in macrophage cells. The in vivo results also demonstrated that ZSCME significantly decreased the parasite load and the diameter of the lesions in the infected mice. Our results demonstrate the promising in vitro and in vivo antileishmanial effects of ZSCME against of L. major. Although the findings of the present study showed some possible antileishmanial mechanisms of ZSCME, such as stimulating NO production, apoptosis, and increasing plasma membrane permeability, additional investigations are required to confirm these results.

Zinc 1,2,4-triazolo[1,5-a]pyrimidine complexes: synthesis, structural characterization and their effect against Chagas disease

BACKGROUND

The World Health Organization catalogues illnesses such as Chagas disease as neglected diseases, due the low investment in new drugs to fight them. The search for novel and non-side effects anti-parasitic compounds is one of the urgent needs of the Third World. The use of triazolopyrimidines and their metal complexes have demonstrated hopeful results in this field.

OBJECTIVE

This work studies the antiparasitic efficacy against Trypanosoma cruzi strains of a series of zinc triazolopyrimidine complexes.

METHOD

A series of Zn complexes has been synthesized by the reaction between the triazolopyrimidine derivatives 7-amino-1,2,4-triazolo[1,5-a]pyrimidine (7atp) and 5,7-dimethyl-1,2,4-triazolo[1,5-a]pyrimidine (dmtp) with Zn(SO4) • 7H2O, ZnCl2, and Zn(NO3)2 • 6H2O salts. The complexes have been analyzed by spectroscopic and thermal assays and X-ray diffraction methods have been used to dilucidate the crystalline structure of one of them. The antiparasitic efficacy was tested in vitro against Trypanosoma cruzi to compare the trypanocidal effect of different ligands and counteranions to fight Chagas disease.

RESULTS

The efficacy of these compounds against Trypanosoma cruzi has also been tested to compare the influence of different ligands and counteranions on the trypanocidal effect against Chagas disease.

CONCLUSION

Antiproliferative tests corroborate the synergistic trypanocidal effect of the triazolopyrimidine coordination complexes.

Comparative assessment of interventions for treating cutaneous leishmaniasis: A network meta-analysis of randomized clinical trials

INTRODUCTION

Various interventions including laser therapy, heat therapy, and several drugs have been trialed in patients with cutaneous leishmaniasis. Due to the lack of an evidence-based comparison of all these interventions, we carried out the present network meta-analysis.

METHODS

Electronic databases were searched for randomized clinical trials evaluating the efficacy and safety of any interventions in patients with cutaneous leishmaniasis. The proportion of patients with complete cure was the primary outcome. The proportion of lesions cured at the end of treatment, the proportion of lesions with minimal/no response to treatment, and proportion of wounds with minimal/no change were the secondary outcomes. Random-effects modeling was used for generating pooled estimates. Rankogram plot was used for identifying the 'best intervention'. For interventions containing a combination of treatments, backslash (/) has been used for depicting the same.

RESULTS

One-hundred and thirty-one studies were included. Intralesional meglumine, topical paromomycin/gentamicin, topical paromomycin, parenteral sodium stibogluconate, topical honey/intralesional meglumine, topical liposomal amphotericin B, oral zinc sulphate, oral miltefosine, parenteral meglumine, heat therapy, topical liposomal azithromycin, intralesional meglumine/silver dressing, intralesional sodium stibogluconate, parenteral meglumine/intralesional meglumine, oral allopurinol/parenteral meglumine, topical trichloroacetic acid/heat therapy, oral zinc sulphate/oral ketoconazole, topical imiquimod/cryotherapy, intralesional meglumine/cryotherapy, topical herbal extract of Z-HE, parenteral pentamidine, topical trichloroacetic acid/intralesional meglumine, carbon-dioxide laser, topical recombinant granulocyte-macrophage colony-stimulating factor/parenteral meglumine, intralesional dapsone, carbon-dioxide laser/intralesional meglumine, moist wet dressing with sodium hypochlorite, parenteral sodium stibogluconate/intralesional recombinant granulocyte-macrophage colony-stimulating factor, oral dapsone, intralesional sodium stibogluconate/oral ketoconazole, intralesional sodium stibogluconate/parenteral sodium stibogluconate and electrocautery/moist wet dressing with sodium hypochlorite were observed with significantly greater proportion of patients with complete cure compared to placebo/untreated controls. Rankogram analysis revealed that parenteral pentamidine has the highest statistical probability of being the best in the pool.

CONCLUSION

We observed several interventions to be effective for treating cutaneous leishmaniasis. However, greater caution is required in interpreting the results as the estimates are likely to change with the advent of results from future studies.

Detection of cutaneous leishmaniasis in three communities of Oti Region, Ghana

Background

Cutaneous leishmaniasis (CL) is the most common type of leishmaniasis, a neglected tropical disease caused by parasites of the genus Leishmania. In Ghana, some studies in the Volta region have detected Leishmania parasites among persons with skin ulcers.

Methodology/Principal findings

Using a cross-sectional study design, the prevalence of CL in three communities of the Oti Region of Ghana was investigated. Demographic and epidemiological data were obtained by a structured interviewer administered questionnaire. A total of 426 (12.4%) out of 3,440 participants screened had at least one skin ulcer. Of 595 skin ulcers sampled and tested by PCR for Leishmania infection, 150 (25.2%) ulcers from 136 individuals tested positive, accounting for an overall CL prevalence of 31.9% among persons with skin ulcers. Individual community CL prevalence of 23.2%, 29.8%, and 36.8% was observed in Ashiabre, Keri, and Sibi Hilltop respectively among persons with skin ulcers.

Conclusions/Significance

Confirmation of CL in the study area suggests an active cycle of transmission of Leishmania infection. The observation of skin ulcers which tested negative to Leishmania infection suggests a need to test for additional causes of skin ulcers such as Treponema pallidum pertenue and Mycobacterium ulcerans in the study area.

Cutaneous leishmaniasis (CL) is a neglected tropical disease caused by parasites of the genus Leishmania and is transmitted by various species of female sandflies. CL usually begins as painless nodules and is usually characterized by skin ulcers which may be single or multiple. Although ulcers due to CL are often self-healing, they may become painful and result in scarring after healing. Typically, CL occurs on exposed parts of the body such as the neck, limbs, and face, which may be easily accessible to sandflies. Although cases of CL had previously been reported in some parts of the Volta region of Ghana, no previous case of CL had been reported in the Oti region. This study was initiated following reports of skin ulcers which were suggestive of CL in some communities of the Oti region. This study confirmed Leishmania infection in 150(25.5%) out of 595 skin ulcer samples obtained from 426 study participants. Given that 445(74,8%) of the skin ulcers tested negative for Leishmania parasite suggests a need for investigation of additional causes of skin ulcers such as yaws and Buruli ulcer in the study area.

Molecular diagnosis and therapy for cutaneous leishmaniasis of a returned traveler from Mexico

Leishmaniasis is prevalent in Southern Europe, the Middle East, India, Africa, and Central and South America. Cutaneous leishmaniasis may spontaneously heal over time without treatment; however, risk of visceral dissemination and the impact of cosmetic defect are important concerns. We report a Case of cutaneous leishmaniasis in a patient who ever traveled to Mexico before the onset of a deteriorating wound around the swollen left eyebrow. A diagnosis of infection with Leishmania mexicana was made based on histopathological examination and molecular identification. Systemic treatment with liposomal amphotericin B and ketoconazole were administered with gradual healing of the lesion. Also, this traveler case implicates that the spread of endemic parasitic diseases may be a concealed risk on the public health for Taiwan underlying globalization.

Application of laser for treatment of cutaneous leishmaniasis: a review of literature

Cutaneous leishmaniasis (CL) is a major health problem in developing countries with high economic and health impact. Despite suggested treatment for CL, there is still no definite therapy for this infection, and many of these treatments are associated with serious local and systemic side effects. In the current paper, use of different laser types including continuous and fractional CO2, argon, PDL, erbium glass, and Nd:YAG have been reviewed. Based on our review, given the high reported efficacy and low side-effect profile, use of laser can be considered as a good alternative to standard treatment of cutaneous leishmaniasis (CL). Performing more studies using different types of lasers is recommended to evaluate the efficacy of this method for treatment of CL.

Tropical and Subtropical Parasitic Diseases: Targets for a New Approach to Virtual Screening

Computational techniques are widely used to reduce costs associated with new drug development with the ability to bind a specific molecular target. These studies need a Brookhaven protein data bank structure sample of the enzyme interaction with an inhibitor of adequate size. In this context, a new computational methodology is postulated to be used when there are no published samples fulfilling this requirements. In this study, 7 compounds, which showed anti-T. cruzi, L. donovani and L. infantum properties, and proved to be inhibitors of their Fe-SOD enzymes, have been theoretically evaluated against related parasites Fe-SOD enzymes, which have been proposed as targets for antiparasitic drugs. This methodology may be applied to similar cases and also to generate starting structures to be used with different CADD methods.

First Example of Antiparasitic Activity Influenced by Thermochromism: Leishmanicidal Evaluation of 5,7-dimethyl-1,2,4-triazolo[1,5-a]pyrimidine Metal Complexes

BACKGROUND

The World Health Organization catalogues illnesses such as Leishmaniasis as neglected diseases, due to low investment in new drugs to fight them. The search of novel and non-side effects anti-parasitic compounds is one of the urgent needs for the Third World. The use of triazolopyrimidines and their metallic complexes has demonstrated hopeful results in this field.

OBJECTIVE

This work studies the antiparasitic efficacy of a series of 5,7-dimethyl-1,2,4- triazolo[1,5-a]pyrimidine first row transition metal complexes against three leishmania spp. strains.

METHODS

The in vitro antiproliferation of promastigote forms of different strains of leishmania spp. (L. infantum, L. braziliensis and L donovani) and the cytotoxicity in macrophage host cells are reported here. The antiparasitic assays have been complemented with enzymatic tests to elucidate the mechanisms of action. New crystal structure description, thermal analysis, magnetic susceptibility and magnetization experiments have also been carried out in order to present a whole characterization of the studied compounds and interesting physical properties besides the biological tests.

RESULTS

The results of antiproliferation screening and cytotoxicity show great antiparasitic efficacy in the studied complexes. The superoxide dismutase enzymatic assays exhibit a different behaviour according to the thermochromic triazolopyrimidine form tested.

CONCLUSION

Antiproliferative assays and enzymatic tests corroborate the synergetic leishmanicidal effect present in coordination triazolopyrimidine complexes. The changes in coordination sphere derived from thermochromism affect the physical properties as well as the biological efficacy.

Anti-leishmanial effect of spiro dihydroquinoline-oxindoles on volume regulation decrease and sterol biosynthesis of Leishmania braziliensis

Diverse spiro dihydroquinoline-oxindoles (JS series) were prepared using the BF₃•OEt₂-catalyzed imino Diels-Alder reaction between ketimine-isatin derivatives and trans-isoeugenol. Ten spiro-oxiindole derivatives were selected and evaluated at different stages of the life cycle of Leishmania braziliensis parasites, responsible for cutaneous leishmaniasis in South America. Among them, the 8'-ethyl-4'-(4-hydroxy-3-methoxyphenyl)-3'-methyl-3',4'-dihydro-1'H-spiro[indoline-3,2'-quinolin]-2-one called JS87 was able to inhibit the growth of promastigotes without affecting the mammalian cells viability, and to decrease the number of intracellular amastigotes of L. braziliensis. This spiro compound was found to act through the alteration of parasite internal regulation by disrupting the regulatory volume decrease (RVD), and to affect the sterol biosynthetic pathway at level of squalene epoxidase (SE) enzyme. These results revealed that the spiro annulation between quinoline and oxindole scaffolds enhances the anti-leishmanial activity, and could assist in the development of potent quinoline-oxindole hybrids against Leishmania braziliensis, the main etiological agent of cutaneous leishmaniasis in South America.

Parasitic Infections of the Skin and Subcutaneous Tissues

A variety of arthropods, protozoa, and helminths infect the skin and subcutaneous tissues and may be identified by anatomic pathologists in standard cytology and histology preparations. The specific organisms seen vary greatly with the patient's exposure history, including travel to or residence in endemic countries. Arthropods are the most commonly encountered parasites in the skin and subcutaneous tissues and include Sarcoptes scabei, Demodex species, Tunga penetrans, and myiasis-causing fly larvae. Protozoal parasites such as Leishmania may also be common in some settings. Helminths are less often seen, and include round worms (eg, Dirofilaria spp.), tapeworms (eg, Taenia solium, Spirometra spp.), and flukes (eg, Schistosoma spp.). This review covers the epidemiologic and histopathologic features of common parasitic infections of the skin and subcutaneous tissues.

Dipeptidyl peptidase 3, a novel protease from Leishmania braziliensis

The increase of leishmaniasis cases worldwide and the emergence of Leishmania strains resistant to current treatments make necessary to find new therapeutic targets. Proteases are appealing drug targets because they play pivotal roles in facilitating parasite survival and promoting pathogenesis. Enzymes belonging to the dipeptidyl peptidase 3 (DPP3) group have been described in different organisms such as mammals, insects and yeast, in which these enzymes have been involved in both protein turnover and protection against oxidative damage. The aim of this work was to characterize the structure and function of the Leishmania braziliensis DPP3 (LbDPP3) protein as the first step to elucidate its suitability as a potential drug target. Sequence alignment showed 43% of identity between LbDPP3 and its human orthologous (hDPP3) enzyme. Although the modeled protein adopted a globally conserved three-dimensional (3D) structure, structural differences were found in the vicinity of the active site and the substrate binding-cleft. In addition, the Leishmania protein was expressed as a soluble recombinant protein and its kinetics parameters were determined using the z-Arginine-Arginine-AMC substrate. The LbDPP3 activity was maximal at pH values between 8.0–8.5. Interestingly, classical enzyme inhibitors such as the tynorphin and its derivative peptide IVYPW were found to actively inhibit the LbDPP3 activity. Moreover, these DPP3 inhibitors showed a detrimental effect upon parasite survival, decreasing the viability of promastigotes by up to 29%. Finally, it was observed that LbDPP3 was equally expressed along the in vitro differentiation from promastigotes to axenic amastigotes. In conclusion, these findings suggest that the L. brazileinsis DPP3 could be a promising drug target.

Cost-effectiveness analysis of thermotherapy versus pentavalent antimonials for the treatment of cutaneous leishmaniasis

OBJECTIVE

The treatment of cutaneous leishmaniasis is toxic, has contraindications, and a high cost. The objective of this study was to estimate the cost-effectiveness of thermotherapy versus pentavalent antimonials for the treatment of cutaneous leishmaniasis.

METHODS

Effectiveness was the proportion of healing and safety with the adverse effects; these parameters were estimated from a controlled clinical trial and a meta-analysis. A standard costing was conducted. Average and incremental cost-effectiveness ratios were estimated. The uncertainty regarding effectiveness, safety, and costs was determined through sensitivity analyses.

RESULTS

The total costs were $66,807 with Glucantime and $14,079 with thermotherapy. The therapeutic effectiveness rates were 64.2% for thermotherapy and 85.1% for Glucantime. The average cost-effectiveness ratios ranged between $721 and $1275 for Glucantime and between $187 and $390 for thermotherapy. Based on the meta-analysis, thermotherapy may be a dominant strategy.

CONCLUSION

The excellent cost-effectiveness ratio of thermotherapy shows the relevance of its inclusion in guidelines for the treatment.

Efficacy of thermotherapy to treat cutaneous leishmaniasis: a meta-analysis of controlled clinical trials

Introduction

The efficacy of thermotherapy for the treatment of cutaneous leishmaniasis presents diverse results with low statistical power.

Objective

To evaluate the efficacy of thermotherapy to treat cutaneous leishmaniasis.

Methods

A meta-analysis of controlled clinical trials in 12 databases based on the implementation of a research protocol with inclusion and exclusion criteria and an assessment of methodological quality. The reproducibility and completeness were guaranteed in the information search and extraction. Heterogeneity, sensitivity and publication bias were assessed by graphical methods (Galbraith, L'Abblé, funnel plot, Egger plot, and influence plot) and analytical methods (DerSimonian-Laird, Begg and Egger). Random-effects forest plots were constructed, and a cumulative meta-analysis was performed.

Results

Eight studies were included with 622 patients who underwent thermotherapy, with an efficacy of 73.2% (95% confidence interval (CI) = 69.6-76.7%), and with 667 patients who underwent systemic treatment, with an efficacy of 70.6% (95% CI=67.1-74.1%). Heterogeneity between studies, good sensitivity for the combined measure, and no publication bias were observed. The relative risk for comparison of the efficacy of treatment was 1.02 (95%CI=0.91, 1.15), showing that the effectiveness of thermotherapy is equal to that of pentavalent antimonial drugs.

Conclusion

Due to its efficacy, greater safety and lower cost, thermotherapy should be the first treatment option for cutaneous leishmaniasis in areas where the prevalence of the mucocutaneous form is low and in patients with contraindications to systemic treatment, such as kidney, liver and heart diseases, as well as in pregnant women, infants, and patients with human immunodeficiency virus infection/acquired immune deficiency syndrome.

New perspectives for leishmaniasis chemotherapy over current anti-leishmanial drugs: a patent landscape

INTRODUCTION

Although leishmaniasis is estimated to cause the ninth largest disease burden among individual infectious diseases, it is still one of the most neglected diseases in terms of drug development. Current drugs are highly toxic, resistance is common and compliance of patients to treatment is low, as treatment is long and drug price is high.

AREAS COVERED

In this review, the authors carried out a patent landscape in search for new perspectives for leishmaniasis therapy. This search encompassed patent documents having priority date between 1994 and 2014. Selected compounds were compared to current anti-leishmanial drugs regarding efficacy and toxicity, when experimental data were available.

EXPERT OPINION

Most patents related to drugs for leishmaniasis have not been produced by the pharmaceutical industry but rather by public research institutes or by universities, and the majority of the inventions disclosed are still in preclinical phase. There is an urgent need to find new ways of funding research for leishmaniasis drugs, incentivizing product development partnerships and pushing forward innovation.

Triazolopyrimidine compounds containing first-row transition metals and their activity against the neglected infectious Chagas disease and leishmaniasis

Leishmaniasis and Chagas disease remain a significant global problem. Current treatments have serious disadvantage due to cost, toxicity, long therapy duration and resistance. In the last years increasing interest has arisen in drug development to fight both diseases. Recently, metal-based drugs have revealed as promising drugs in a variety of therapeutic areas. Herein we describe six newly synthesized transition metal complexes with a bioactive molecule 5,7-dimethyl-1,2,4-triazolo[1,5-a]pyrimidine (dmtp). All of them have been characterized by X-ray, spectroscopic and thermal methods. In vitro and in vivo studies (murine model) on the antiproliferative activity of these complexes against Leishmania spp. (Leishmania infantum, Leishmania braziliensis) and Trypanosoma cruzi have been carried out. Our results reveal a strong potential of three of the assayed compounds as antiparasitic agents against the above-mentioned infectious diseases.

In vitro and in vivo leishmanicidal activity of Astronium fraxinifolium (Schott) and Plectranthus amboinicus (Lour.) Spreng against Leishmania (Viannia) braziliensis

The aim of the present work was to evaluate antileishmanial activity of Astronium fraxinifolium and Plectranthus amboinicus. For the in vitro tests, essential oil of P. amboinicus (OEPA) and ethanolic extracts from A. fraxinifolium (EEAF) were incubated with 10(6) promastigotes of L. (Viannia) braziliensis. The OEPA was able to reduce the parasite growth after 48 h; nonetheless, all the EEAFs could totally abolish the parasite growth. For the in vivo studies, BALB/c mice were infected subcutaneously (s.c.) with 10(7) L. braziliensis promastigotes. Treatment was done by administering OEPA intralesionally (i.l.) for 14 days. No difference was found in lesion thickness when those animals were compared with the untreated animals. Further, golden hamsters were infected s.c. with 10(6) L. braziliensis promastigotes. The first protocol of treatment consisted of ethanolic leaf extract from A. fraxinifolium (ELEAF) administered i.l. for 4 days and a booster dose at the 7th day. The animals showed a significant reduction of lesion thickness in the 6th week, but it was not comparable to the animals treated with Glucantime. The second protocol consisted of 15 daily intralesional injections. The profiles of lesion thickness were similar to the standard treatment. In conclusion, in vivo studies showed a high efficacy when the infected animals were intralesionally treated with leaf ethanolic extract from A. fraxinifolium.

Ketanserin, an antidepressant, exerts its antileishmanial action via inhibition of 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR) enzyme of Leishmania donovani

Leishmaniasis is one of the major health problems existing globally. The current chemotherapy for leishmaniasis presents several drawbacks like toxicity and increased resistance to existing drugs, and hence, there is a necessity to look out for the novel drug targets and new chemical entities. Current trend in drug discovery arena is the "repurposing" of old drugs for the treatment of diseases. In the present study, an antidepressant, ketanserin, was found lethal to both Leishmania donovani promastigotes and intracellular amastigotes with no apparent toxicity to the cells. Ketanserin killed promastigotes and amastigotes with an IC50 value of 37 μM and 28 μM respectively, in a dose-dependent manner. Ketanserin was found to inhibit L. donovani recombinant 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR) enzyme with an IC50 value of 43 μM. Ketanserin treated promastigotes were exogenously supplemented with sterols like ergosterol and cholesterol to rescue cell death. Ergosterol could recover the inhibition partially, whereas cholesterol supplementation completely failed to rescue the inhibited parasites. Further, HMGR-overexpressing parasites were generated by transfecting Leishmania promastigotes with an episomal pspα hygroα-HMGR construct. Wild-type and HMGR overexpressors of L. donovani were used to study the effect and mode of action of this inhibitor. The HMGR overexpressors showed twofold resistance to ketanserin. These observations suggest that the lethal effect of ketanserin is due to inhibition of HMGR, the rate-limiting enzyme of the ergosterol biosynthetic pathway. Since targeting of the sterol biosynthetic pathway enzymes may be useful therapeutically, the present study may have implications in treatment of leishmaniasis.

In vitro leishmanicidal activity of pyrazole-containing polyamine macrocycles which inhibit the Fe-SOD enzyme of Leishmania infantum and Leishmania braziliensis species

The in vitro leishmanicidal activity and cytotoxicity of pyrazole-containing macrocyclic polyamines 1–4 was assayed on Leishmania infantum and Leishmania braziliensis species. Compounds 1–4 were more active and less toxic than glucantime and both infection rates and ultrastructural alterations confirmed that 1 and 2 were highly leishmanicidal and induced extensive parasite cell damage. Modifications in the excretion products of parasites treated with 1–3 were also consistent with substantial cytoplasm alterations. Compound 2 was highlighted as a potent inhibitor of Fe-SOD in both species, whereas its effect on human CuZn-SOD was poor. Molecular modelling suggested that 2 could deactivate Fe-SOD due to a sterically favoured enhanced ability to interact with the H-bonding net that supports the enzyme`s antioxidant features.

Development of an ex vivo lymph node explant model for identification of novel molecules active against Leishmania major

Leishmaniasis is a vector-borne zoonotic infection affecting people in tropical and subtropical regions of the world. Current treatments for cutaneous leishmaniasis are difficult to administer, toxic, expensive, and limited in effectiveness and availability. Here we describe the development and application of a medium-throughput screening approach to identify new drug candidates for cutaneous leishmaniasis using an ex vivo lymph node explant culture (ELEC) derived from the draining lymph nodes of Leishmania major-infected mice. The ELEC supported intracellular amastigote proliferation and contained lymph node cell populations (and their secreted products) that enabled the testing of compounds within a system that mimicked the immunopathological environment of the infected host, which is known to profoundly influence parasite replication, killing, and drug efficacy. The activity of known antileishmanial drugs in the ELEC system was similar to the activity measured in peritoneal macrophages infected in vitro with L. major. Using the ELEC system, we screened a collection of 334 compounds, some of which we had demonstrated previously to be active against L. donovani, and identified 119 hits, 85% of which were confirmed to be active by determination of the 50% effective concentration (EC50). We found 24 compounds (7%) that had an in vitro therapeutic index (IVTI; 50% cytotoxic/effective concentration [CC50]/EC50) > 100; 19 of the compounds had an EC50 below 1 μM. According to PubChem searchs, 17 of those compounds had not previously been reported to be active against Leishmania. We expect that this novel method will help to accelerate discovery of new drug candidates for treatment of cutaneous leishmaniasis.

Development of liposomes loaded with anti-leishmanial drugs for the treatment of cutaneous leishmaniasis

Cutaneous leishmaniasis is caused by different species of Leishmania parasites and its available treatments have not yet provided a strong consistent result. The weak response of current chemotherapeutics is due to their deficient effects on stealth parasites inside macrophages, rapid clearance from the site of action and systemic side effects in high doses. Liposomal formulation of anti-leishmanial drugs could overcome these problems. In this study, different liposomal formulations of three famous anti-leishmanial drugs: Glucantime®, miltefosine and paromomycin were prepared by a modified freeze-drying double emulsion method. Liposome size, zeta potential and encapsulation efficiency were evaluated, and their imaging was carried out by means of atomic force microscopy. Three formulations were evaluated in vivo by subcutaneous injection into skin lesions caused by Leishmania major in BALB/c mice. Encapsulation efficiency of prepared liposomes was up to 90%; however, they inherited a bimodal size distribution that caused their encapsulation efficiency to decrease to 50% during filtering sterilization. Besides, the effect of surface charge was significant on preparation procedure, size and encapsulation efficiency. All three formulations reduced amastigote counts and lesion size but only miltefosine-loaded formulations had significant therapeutic effects compared with control group (p < 0.05).

Outbreak of cutaneous leishmaniasis in Fuenlabrada, Madrid

BACKGROUND

Leishmaniasis, an endemic infection in Spain, is caused by protozoan parasites of the Leishmania genus. Between 2010 and 2012, there was an outbreak of cutaneous and visceral leishmaniasis in Fuenlabrada, Madrid.

OBJECTIVES

To describe the cases of cutaneous leishmaniasis diagnosed over a 17-month period at the dermatology department of Hospital de Fuenlabrada.

MATERIAL AND METHODS

We analyzed the epidemiological, clinical, histological, and microbiological features of each case and also evaluated the treatments administered and outcomes.

RESULTS

We studied 149 cases. The incidence of cutaneous leishmaniasis showed a peak in the age range between 46 and 60 years and was similar in men and women. At the time of consultation, the lesions had been present for between 2 and 6 months in the majority of patients. The most common clinical presentation was with erythematous plaques and papules without crusts (52% of cases). Lesions were most often located in sun-exposed areas and were multiple in 57% of patients. In 67% of cases, the histological study showed non-necrotizing granulomatous dermatitis with no evidence of parasites using conventional staining methods. Diagnosis was confirmed by polymerase chain reaction (PCR) in 98% of patients. In the remaining cases, the histological study revealed Leishman-Donovan bodies in the skin. Intralesional pentavalent antimonials were the most commonly used drugs (76% of cases) and produced satisfactory results.

CONCLUSIONS

We have presented a large series of cases of cutaneous leishmaniasis diagnosed in the context of an outbreak. Multiple papules were the most common clinical presentation, with histology that showed non-necrotizing granulomatous dermatitis with no evidence of parasites. PCR of skin samples was the test that most frequently provided the diagnosis.

New world cutaneous leishmaniasis treated with intralesional injection of pentavalent antimony

Cutaneous leishmaniasis is a skin infection caused by the Leishmania species, an intracellular protozoan parasite that is transmitted by various species of female sandflies. According to the geographic distribution and vectors, leishmaniasis is classified as Old World or New World cutaneous leishmaniasis. In Korea, 24 cases of Old World cutaneous leishmaniasis have been reported, but New World cutaneous leishmaniasis has not been reported as yet. A 37-year-old man presented with a 3-month history of a painful and erythematous nodule with two satellite papules on the left postauricular area and a papule on the left arm after traveling to the Amazon region in Brazil. After we performed skin biopsies of the lesions, diagnosis of cutaneous leishmaniasis was made by the histopathological findings. After intralesional injection of sodium stibogluconate (Pentostam®, GlaxoSmithKline) twice a week for 4 weeks, the lesions improved with scarring. Herein, we discuss this case of New World cutaneous leishmaniasis that was successfully treated with intralesional injection of sodium stibogluconate (Pentostam®) in Korea.

Thermotherapy. An alternative for the treatment of American cutaneous leishmaniasis

BACKGROUND

Pentavalent antimonials (Sb5) and miltefosine are the first-line drugs for treating cutaneous leishmaniasis in Colombia; however, toxicity and treatment duration negatively impact compliance and cost, justifying an active search for better therapeutic options. We compared the efficacy and safety of thermotherapy and meglumine antimoniate for the treatment of cutaneous leishmaniasis in Colombia.

METHOD

An open randomized Phase III clinical trial was performed in five military health centres. located in northwestern, central and southern Colombia. Volunteers with parasitological positive diagnosis (Giemsa-stained smears) of cutaneous leishmaniasis were included. A single thermotherapy session involving the application of 50°C at the center and active edge of each lesion. Meglumine antimoniate was administered intramuscularly at a dose of 20 mg Sb5/kg weight/day for 20 days.

RESULTS

Both groups were comparable. The efficacy of thermotherapy was 64% (86/134 patients) by protocol and 58% (86/149) by intention-to-treat. For the meglumine antimoniate group, efficacy by protocol was 85% (103/121 patients) and 72% (103/143) by intention-to-treat, The efficacy between the treatments was statistically significant (p 0.01 and < 0.001) for analysis by intention to treat and by protocol, respectively. There was no difference between the therapeutic response with either treatment regardless of the Leishmania species responsible for infection. The side effects of meglumine antimoniate included myalgia, arthralgia, headache and fever. Regarding thermotherapy, the only side effect was pain at the lesion area four days after the initiation of treatment.

CONCLUSION

Although the efficacy rate of meglumine antimoniate was greater than that of thermotherapy for the treatment of cutaneous leishmaniasis, the side effects were also greater. Those factors, added to the increased costs, the treatment adherence problems and the progressive lack of therapeutic response, make us consider thermotherapy as a first line treatment for cutaneous leishmaniasis.