Phylogenetic analysis and antimony resistance of Leishmania major isolated from humans and rodents.

Cutaneous Leishmaniasis (CL) is one of the world's neglected diseases which is caused by Leishmania spp. The aim of this study was to assess molecular profile and antimony resistance of Leishmania isolated from human and rodent hosts. Samples were collected from suspected CL patients referred to health centres and wild rodent's traps in Gonbad-e-Qabus region, north-eastern Iran. Smears were subjected to PCR-RFLP to identify Leishmania species. In addition, ITS1-PCR products were sequenced for phylogenetic analysis. Clinical isolates and rodent samples were subjected to MTT assay to determine IC50 values and in vitro susceptibilities. Expression levels of antimony resistance-related genes were determined in CL isolates. Out of 1,949 suspected patients with CL and 148 rodents, 1,704 (87.4%) and 6 (4.05%) were positive with direct smear, respectively. Digestion patterns of BusRI (HaeIII) endonuclease enzyme were similar to what expected for Leishmania major. Phylogenetic analysis revealed that the highest interspecies similarity was found between current L. major sequences with L. major obtained from Russia and Uzbekistan. Out of 20 L. major samples tested, 13 (65%) were resistant to meglumine antimoniate (MA) treatment, with an activity index (AI) exceeding 4. The remaining 7 samples (35%) responded to MA treatment and were classified as sensitive isolates, with a confirmed sensitive phenotype based on their AI values. The comparison expression analysis of three major antimony resistance-associated genes in unresponsive clinical isolates demonstrated significant fold changes for TDR1 (4.78-fold), AQP1 (1.3-fold), and γ-GCS (1.17-fold) genes (P < 0.05). Herein, we demonstrate genetic diversity and antimony resistance of L. major isolated from human and reservoir hosts in north-eastern Iran, which could be the basis for planning future control strategies.

Potential selection of antimony and methotrexate cross-resistance in Leishmania infantum circulating strains.

BACKGROUND: Visceral leishmaniasis (VL) resolution depends on a wide range of factors, including the instauration of an effective treatment coupled to a functional host immune system. Patients with a depressed immune system, like the ones receiving methotrexate (MTX), are at higher risk of developing VL and refusing antileishmanial drugs. Moreover, the alarmingly growing levels of antimicrobial resistance, especially in endemic areas, contribute to the increasing the burden of this complex zoonotic disease. PRINCIPAL FINDINGS: To understand the potential links between immunosuppressants and antileishmanial drugs, we have studied the interaction of antimony (Sb) and MTX in a Leishmania infantum reference strain (LiWT) and in two L. infantum clinical strains (LiFS-A and LiFS-B) naturally circulating in non-treated VL dogs in Spain. The LiFS-A strain was isolated before Sb treatment in a case that responded positively to the treatment, while the LiFS-B strain was recovered from a dog before Sb treatment, with the dog later relapsing after the treatment. Our results show that, exposure to Sb or MTX leads to an increase in the production of reactive oxygen species (ROS) in LiWT which correlates with a sensitive phenotype against both drugs in promastigotes and intracellular amastigotes. LiFS-A was sensitive against Sb but resistant against MTX, displaying high levels of protection against ROS when exposed to MTX. LiFS-B was resistant to both drugs. Evaluation of the melting proteomes of the two LiFS, in the presence and absence of Sb and MTX, showed a differential enrichment of direct and indirect targets for both drugs, including common and unique pathways. CONCLUSION: Our results show the potential selection of Sb-MTX cross-resistant parasites in the field, pointing to the possibility to undermine antileishmanial treatment of those patients being treated with immunosuppressant drugs in Leishmania endemic areas.

Antimony resistance and gene expression in Leishmania: spotlight on molecular and proteomic aspects.

Leishmaniasis is a vector-borne parasitic disease caused by Leishmania parasites with a spectrum of clinical manifestations, ranging from skin lesions to severe visceral complications. Treatment of this infection has been extremely challenging with the concurrent emergence of drug resistance. The differential gene expression and the discrepancies in protein functions contribute to the appearance of 2 distinct phenotypes: resistant and sensitive, but the current diagnostic tools fail to differentiate between them. The identification of gene expression patterns and molecular mechanisms coupled with antimony (Sb) resistance can be leveraged to prompt diagnosis and select the most effective treatment methods. The present study attempts to use comparative expression of Sb resistance-associated genes in resistant and sensitive Leishmania, to disclose their relative abundance in clinical or in vitro selected isolates to gain an understanding of the molecular mechanisms of Sb response/resistance. Data suggest that the analysis of resistance gene expression would verify the Sb resistance or susceptibility only to a certain extent; however, none of the individual expression patterns of the studied genes was diagnostic as a biomarker of Sb response of Leishmania. The findings highlighted will be useful in bridging the knowledge gap and discovering innovative diagnostic tools and novel therapeutic targets.

Production and radiochemistry of antimony-120m: Efforts toward Auger electron therapy with 119Sb.

Targeted Meitner-Auger Therapy (TMAT) has potential for personalized treatment thanks to its subcellular dosimetric selectivity, which is distinct from the dosimetry of ß- and α particle emission based Targeted Radionuclide Therapy (TRT). To date, most clinical and preclinical TMAT studies have used commercially available radionuclides. These studies showed promising results despite using radionuclides with theoretically suboptimal photon to electron ratios, decay kinetics, and electron emission spectra. Studies using radionuclides whose decay characteristics are considered more optimal are therefore important for evaluation of the full potential of Meitner-Auger therapy; 119Sb is among the best such candidates. In the present work, we develop radiochemical purification of 120Sb from irradiated natural tin targets for TMAT studies with 119Sb.

Novel Pyrido[2',1':2,3]imidazo[4,5-c]quinoline Derivative Selectively Poisons Leishmania donovani Bisubunit Topoisomerase 1 to Inhibit the Antimony-Resistant Leishmania Infection in Vivo.

The unique bisubunit structure of Leishmania donovani topoisomerase 1B (LdTop1) is a potential drug target in the parasites unlike the monomeric Top1 from its human host counterpart. Here, we report the design, synthesis, and validation of a chimeric pyrido[2',1':2,3]imidazo[4,5-c]quinoline derivative (C17) as a novel antileishmanial agent that poisons topoisomerase 1-DNA covalent complexes (LdTop1cc) inside the parasites and inhibits Top1 religation activity both in the drug sensitive and antimony-resistant L. donovani clinical isolates. Importantly, the human Top1 is not sensitive to C17. Further, C17 overcomes the chemical instability of camptothecin (CPT) by generating persistent LdTop1cc-induced DNA breaks inside the parasites even after 12 h of drug removal. Intraperitoneal administration of C17 results in marked reduction of the Leishmania amastigotes from the infected spleen and liver of BALB/c mice. C17 confers a host protective immune-response up-regulating the Th1 cytokines facilitating parasite clearance which can be exploited for treating drug-resistant leishmaniasis.

Antimony resistance mechanism in genetically different clinical isolates of Indian Kala-azar patients.

The central theme of this enterprise is to find common features, if any, displayed by genetically different antimony (Sb)-resistant viscerotropic Leishmania parasites to impart Sb resistance. In a limited number of clinical isolates (n = 3), we studied the breadth of variation in the following dimensions: (a) intracellular thiol content, (b) cell surface expression of glycan having N-acetyl-D-galactosaminyl residue as the terminal sugar, and (c) gene expression of thiol-synthesizing enzymes (CBS, MST, gamma-GCS, ODC, and TR), antimony-reducing enzymes (TDR and ACR2), and antimonial transporter genes (AQP1, MRPA, and PRP1). One of the isolates, T5, that was genotypically characterized as Leishmania tropica, caused Indian Kala-azar and was phenotypically Sb resistant (T5-LT-SSG-R), while the other two were Leishmania donovani, out of which one isolate, AG83, is antimony sensitive (AG83-LD-SSG-S) and the other isolate, T8, is Sb resistant (T8-LD-SSG-R). Our study showed that the Sb-resistant parasites, regardless of their genotype, showed significantly higher intracellular thiol compared with Sb-sensitive AG83-LD-SSG-S. Seemingly, T5-LT-SSG-R showed about 1.9-fold higher thiol content compared with T8-LD-SSG-R which essentially mirrored cell surface N-acetyl-D-galactosaminyl expression. Except TR, the expression of the remaining thiol-synthesizing genes was significantly higher in T8-LD-SSG-R and T5-LT-SSG-R than the sensitive one, and between the Sb-resistant parasites, the latter showed a significantly higher expression. Furthermore, the genes for Sb-reducing enzymes increased significantly in resistant parasites regardless of genotype compared with the sensitive one, and between two resistant parasites, there was hardly any difference in expression. Out of three antimony transporters, AQP1 was decreased with the concurrent increase in MRPA and PRP1 in resistant isolates when compared with the sensitive counterpart. Interestingly, no difference in expression of the above-mentioned transporters was noted between two Sb-resistant isolates. The enduring image that resonated from our study is that the genetically diverse Sb-resistant parasites showed enhanced thiol-synthesizing and antimony transporter gene expression than the sensitive counterpart to confer a resistant phenotype.

Treatment outcome of imported cutaneous leishmaniasis among travelers and migrants infected with Leishmania major and Leishmania tropica: a retrospective study in European centers 2013 to 2019.

OBJECTIVES: Cutaneous leishmaniasis (CL) in Asia, Northern, and Sub-Saharan Africa is mainly caused by Leishmania major and Leishmania tropica. We describe and evaluate the treatment outcome of CL among travelers and migrants in Europe. METHODS: We conducted a retrospective study of parasitological confirmed CL cases caused by L. major and L. tropica during 2013-2019 in Europe. Data were collected from medical records and databases within the LeishMan network. RESULTS: Of 206 included cases of CL, 75 were identified as L. major and 131 as L. tropica. Of patients with L. tropica infection, 80% were migrants, whereas 53% of patients with L. major infection had been visiting friends and relatives. Among patients with L. tropica, 48% were younger than 15 years. Pentavalent antimony cured 73% (L. major) and 78% (L. tropica) of patients. The cure rate for intralesional administration was 86% and 67% for systemic, on L. tropica. Liposomal amphotericin B had a cure rate of 44-63%. CONCLUSION: L. major infections were mostly found in individuals visiting friends and relatives, whereas L. tropica were mainly identified in migrants. No patients with L. major relapsed. Pentavalent antimony, liposomal amphotericin B, and cryotherapy had cure rates in accordance with previous studies.

Repurposing antiparasitic antimonials to noncovalently rescue temperature-sensitive p53 mutations.

The tumor suppressor p53 is inactivated by over hundreds of heterogenous mutations in cancer. Here, we purposefully selected phenotypically reversible temperature-sensitive (TS) p53 mutations for pharmacological rescue with thermostability as the compound-screening readout. This rational screening identified antiparasitic drug potassium antimony tartrate (PAT) as an agent that can thermostabilize the representative TS mutant p53-V272M via noncovalent binding. PAT met the three basic criteria for a targeted drug: availability of a co-crystal structure, compatible structure-activity relationship, and intracellular target specificity, consequently exhibiting antitumor activity in a xenograft mouse model. At the antimony dose in clinical antiparasitic therapy, PAT effectively and specifically rescued p53-V272M in patient-derived primary leukemia cells in single-cell RNA sequencing. Further scanning of 815 frequent p53-missense mutations identified 65 potential PAT-treatable mutations, most of which were temperature sensitive. These results lay the groundwork for repurposing noncovalent antiparasitic antimonials for precisely treating cancers with the 65 p53 mutations.

Involvement of tryparedoxin peroxidase (TryP) and trypanothione reductase (TryR) in antimony unresponsive of Leishmania tropica clinical isolates of Iran.

Clinical resistance to pentavalent antimonial compounds has long been recognized as a major problem in the treatment of human leishmaniasis. Trypanothione metabolism, the main form of thiol, has shown to play a central role in antimony resistance of laboratory-generated resistant Leishmania spp. and field-isolated resistant L. donovani; but the mechanism of antimony resistance in the clinical isolates of L. tropica causing anthroponotic cutaneous leishmaniasis (ACL) is less studied. Patients were selected among confirmed positive ACL cases who referred to Pasteur Institute of Iran, Tehran, from endemic regions of north-east and south of Iran. L. tropica clinical isolates were collected from patients who were either treatment-responsive (MAS=S1 to S5) or unresponsive (MAR=R1 to R4) to Glucantime® (meglumine antimoniate=MA). Isolates were tested for sensitivity to trivalent antimony (SbIII) in promastigotes and to pentavalent antimony (SbV) in intracellular amastigotes stages. Intracellular thiol levels were assayed and trypanothione-dependent components, including trypanothione reductase (TR) and tryparedoxin peroxidase I (TryP) were analysed at protein level and enzymatic activity in isolates. The MAR isolates had an approximate two fold increase in the levels of intracellular thiols (P< 0.05) accompanied by an average 5-10 fold increase in in vitro resistance to antimony. TryP was amplified at the protein level in all MAR strains as compared to the MAS strains (range: 2.8-5.6 fold). All MAR isolates metabolized H2O2 at higher rates than MAS isolates (8.55±0.75 nmol/min/mg vs. 3.14±0.36 nmol/min/mg) (P< 0.05). In addition, levels of TryR protein were also markedly elevated in 3 out of 4 MAR isolates (range: 2.2-4.1 fold). This was accompanied by overexpressed TryR activity (mean level of 46.83±2.43 for extracts of MAR vs. 20.98±3.02 for MAS strains) (P< 0.05). Elevated levels of TryP, active enzyme in peroxide detoxification, were observed in MAR parasites resulting in an increased metabolism of H2O2. TryR activity was overexpressed on average in extracts of MAR strains, but not in all isolates. Enhanced anti-oxidant defenses through thiol metabolism may play a significant role in clinical resistance of ACL patients to Glucantime.

Characterization of Differentially Abundant Proteins Among Leishmania (Viannia) braziliensis Strains Isolated From Atypical or Typical Lesions.

Leishmania (Viannia) braziliensis is the main etiological agent of cutaneous and mucocutaneous leishmaniasis in Latin America. Non-ulcerated atypical tegumentary leishmaniasis cases caused by L. braziliensis have been reported in several regions of the American continent, including the Xacriabá indigenous reserve in São João das Missões/Minas Gerais, Brazil. Parasites isolated from these atypical clinical lesions are resistant to antimony-based therapeutics. In the present study, proteins displaying differential abundance in two strains of L. braziliensis isolated from patients with atypical lesions compared with four strains isolated from patients with typical lesions were identified using a quantitative proteomics approach based on tandem mass tag labeling (TMT) and mass spectrometry. A total of 532 (P<0.05) differentially abundant proteins were identified (298 upregulated and 234 downregulated) in strains from atypical lesions compared to strains from typical lesions. Prominent positively regulated proteins in atypical strains included those that may confer greater survival inside macrophages, proteins related to antimony resistance, and proteins associated with higher peroxidase activity. Additionally, we identified proteins showing potential as new drug and vaccine targets. Our findings contribute to the characterization of these intriguing L. braziliensis strains and provide a novel perspective on Atypical Cutaneous Leishmaniasis (ACL) cases that have been associated with therapeutic failures.

Wnt5A Signaling Blocks Progression of Experimental Visceral Leishmaniasis.

Visceral leishmaniasis, caused by L. donovani infection is fatal if left untreated. The intrinsic complexity of visceral leishmaniasis complicated further by the increasing emergence of drug resistant L. donovani strains warrants fresh investigations into host defense schemes that counter infections. Accordingly, in a mouse model of experimental visceral leishmaniasis we explored the utility of host Wnt5A in restraining L. donovani infection, using both antimony sensitive and antimony resistant L. donovani strains. We found that Wnt5A heterozygous (Wnt5A +/-) mice are more susceptible to L. donovani infection than their wild type (Wnt5A +/+) counterparts as depicted by the respective Leishman Donovan Units (LDU) enumerated from the liver and spleen harvested from infected mice. Higher LDU in Wnt5A +/- mice correlated with increased plasma gammaglobulin level, incidence of liver granuloma, and disorganization of splenic white pulp. Progression of infection in mice by both antimony sensitive and antimony resistant strains of L. donovani could be prevented by activation of Wnt5A signaling through intravenous administration of rWnt5A prior to L. donovani infection. Wnt5A mediated blockade of L. donovani infection correlated with the preservation of splenic macrophages and activated T cells, and a proinflammatory cytokine bias. Taken together our results indicate that while depletion of Wnt5A promotes susceptibility to visceral leishmaniasis, revamping Wnt5A signaling in the host is able to curb L. donovani infection irrespective of antimony sensitivity or resistance and mitigate the progression of disease.

Differential translational regulation of host exosomal proteins play key role in immunomodulation in antimony resistance in Visceral Leishmaniasis: A proteomic profiling study.

In host-pathogen interactions, exosomal secretions are crucial for cell to cell communication and have an established role in immunomodulation. Protozoans, including Leishmania, modulates their host vesicular secretions for better survival; although the role of exosomal secretions in unresponsive against sodium antimony gluconate (SAG) has never been documented. In this study, the exosomal proteome of RAW macrophages infected with either SAG responsive (SAGS) or SAG unresponsive (SAGR) L. donovani parasites has been compared with uninfected RAW macrophages. Proteins isolated from exosomes were labelled with iTRAQ reagents; followed by subsequent LC-TOF/-MS analysis. In total, 394 proteins (p < 0.05) were identified which were shared common among all sets. Highly differentially expressed proteins were sorted by log2 value -1 and +1 as down regulated and up regulated respectively which yielded 58 proteins in SAGR and 41 proteins during SAGS infection. Out of the 58 proteins identified during SAGR infection, 17 proteins were of immune modulatory function. Network visualization model and pathway analysis revealed the interactions among these proteins via different immunological pathways with reported involvement of some proteins in SAG resistance and host immune modulation. Hence, the differential abundance of immune pathway related proteins in exosomes of infected host during SAGR infection supports the immune modulatory strategy adopted by SAG resistant parasites for enhanced survival .

Serious adverse events following treatment of visceral leishmaniasis: A systematic review and meta-analysis.

BACKGROUND: Despite a historical association with poor tolerability, a comprehensive review on safety of antileishmanial chemotherapies is lacking. We carried out an update of a previous systematic review of all published clinical trials in visceral leishmaniasis (VL) from 1980 to 2019 to document any reported serious adverse events (SAEs). METHODS: For this updated systematic review, we searched the following databases from 1st Jan 2016 through 2nd of May 2019: PUBMED, Embase, Scopus, Web of Science, Cochrane, clinicaltrials.gov, WHO ICTRP, and the Global Index Medicus. We included randomised and non-randomised interventional studies aimed at assessing therapeutic efficacy and extracted the number of SAEs reported within the first 30 days of treatment initiation. The incidence rate of death (IRD) from individual treatment arms were combined in a meta-analysis using random effects Poisson regression. RESULTS: We identified 157 published studies enrolling 35,376 patients in 347 treatment arms. Pentavalent antimony was administered in 74 (21.3%), multiple-dose liposomal amphotericin B (L-AmB) in 52 (15.0%), amphotericin b deoxycholate in 51 (14.7%), miltefosine in 33 (9.5%), amphotericin b fat/lipid/colloid/cholesterol in 31 (8.9%), and single-dose L-AmB in 17 (4.9%) arms. There was a total of 804 SAEs reported of which 793 (including 428 deaths) were extracted at study arm level (11 SAEs were reported at study level only). During the first 30 days, there were 285 (66.6%) deaths with the overall IRD estimated at 0.068 [95% confidence interval (CI): 0.041-0.114; I2 = 81.4%; 95% prediction interval (PI): 0.001-2.779] per 1,000 person-days at risk; the rate was 0.628 [95% CI: 0.368-1.021; I2 = 82.5%] in Eastern Africa, and 0.041 [95% CI: 0.021-0.081; I2 = 68.1%] in the Indian Subcontinent. In 21 study arms which clearly indicated allowing the inclusion of patients with HIV co-infections the IRD was 0.575 [95% CI: 0.244-1.355; I2 = 91.9%] compared to 0.043 [95% CI: 0.020-0.090; I2 = 62.5%] in 160 arms which excluded HIV co-infections. CONCLUSION: Mortality within the first 30 days of VL treatment initiation was a rarely reported event in clinical trials with an overall estimated rate of 0.068 deaths per 1,000 person-days at risk, though it varied across regions and patient populations. These estimates may serve as a benchmark for future trials against which mortality data from prospective and pharmacovigilance studies can be compared. The methodological limitations exposed by our review support the need to assemble individual patient data (IPD) to conduct robust IPD meta-analyses and generate stronger evidence from existing trials to support treatment guidelines and guide future research.

Effectiveness of miltefosine in cutaneous leishmaniasis caused by Leishmania tropica in Pakistan after antimonial treatment failure or contraindications to first line therapy-A retrospective analysis.

BACKGROUND: Cutaneous leishmaniasis (CL) is a neglected tropical skin disease, caused by Leishmania protozoa. In Pakistan, where CL caused by L. tropica is highly endemic, therapy with pentavalent antimonials is the standard of care, but has significant toxicity when used in systemic therapy, while are no evidence-based safer alternative treatment options for L. tropica. The efficacy of oral miltefosine has not been studied in CL caused by L. tropica. We evaluated effectiveness and tolerability of miltefosine in patients with previous treatment failure or with contraindications to systemic antimonial treatment. METHODS: A retrospective review was conducted of a cohort of CL patients who were treated with a 28-day course of miltefosine between December 2017 and August 2019, in urban Quetta, Pakistan, an area endemic for L. tropica. Descriptive analyses were performed, and effectiveness was assessed by initial response after treatment, and final cure at routine follow up visits, six weeks to three months post-treatment. Tolerability was assessed by routinely reported adverse events. RESULTS: Of the 76 CL patients in the cohort, 42 (55%) had contraindications to systemic antimonial treatment, and 34 (45%) had failure or relapse after antimonial treatment. Twelve patients defaulted during treatment and 12 patients were lost to follow up. In the remaining 52 patients, final cure rate was 77% (40/52). In those with contraindications to systemic antimonial treatment the final cure rate was 83% (24/29) and in the failure and relapse group 70% (16/23). Twenty-eight patients (40.0%) reported 39 mild to moderate adverse events with the main complaints being nausea (41.0%), general malaise (25.6%), and stomach pain (12.8%). CONCLUSION: Results indicate that miltefosine is an effective second line treatment in CL in areas endemic for L. tropica. Prospective studies with systematic follow up are needed to obtain definitive evidence of effectiveness and tolerability, including identification of risk factors for miltefosine treatment failure.

A Double-blind, Randomized Trial to Evaluate Miltefosine and Topical Granulocyte Macrophage Colony-stimulating Factor in the Treatment of Cutaneous Leishmaniasis Caused by Leishmania braziliensis in Brazil.

BACKGROUND: The treatment of cutaneous leishmaniasis (CL) in Brazil using pentavalent antimony (Sbv) is associated with a high rate of failure. Miltefosine has proven efficacy for CL caused by L. braziliensis, with a cure rate (CR) of 75%. A combined treatment with granulocyte macrophage colony-stimulating factor (GM-CSF) and miltefosine could increase CR and decrease healing time. METHODS: A randomized, double-blind clinical trial to evaluate the efficacy of miltefosine combined with topical GM-CSF (M + GM) vs miltefosine and placebo (M + P) vs Sbv in 133 patients with CL caused by L. braziliensis in Bahia, Brazil. RESULTS: The final CR at 180 days after the initiation of treatment was 44.4% in the Sbv group, 76.6% in the M + P group (P = .003 vs Sbv), and 75.6% in the M + GM group (P = .004 vs Sbv). The median healing time for cure was 102 days for the Sbv group and 60 days for both miltefosine groups (P = .0009). During the 6-month follow-up period, 4 relapses were documented: 1 in the Sbv group, 1 in the M + P group, and 2 in the M + GM group. Mild adverse events occurred in 65% of patients from the Sbv group, 76% and 79% from the M + P and M + GM groups respectively. CONCLUSIONS: Miltefosine is more effective than Sbv for the treatment of CL caused by L. braziliensis in Brazil and accelerates the healing time. Association with GM-CSF does not improve therapeutic outcome. CLINICAL TRIALS REGISTRATION: NCT03023111.

Application and prospect of antimonene: A new two-dimensional nanomaterial in cancer theranostics.

With the rise of two-dimensional nanomaterials in medicine, finding suitable materials has become our top priority. Since the first report of antimonene in 2015, due to its excellent physical and chemical properties, it has gradually attracted widespread attention, including its application prospects in cancer treatment. In this paper, the preparation, stability and infrared degradability of antimonene, as well as its experimental examples in tumor treatment in recent years are reviewed, the latest research results are listed and summarized, the advantages and existing problems are analyzed, and the future of antimonene in tumor therapy is prospected.

Caracterización clínico epidemiológica de la leishmaniosis visceral infantil / Clinical epidemiological characterization of children visceral leishmaniasis

Introducción: La leishmaniosis visceral es la más grave de las formas clínicas de la leishmaniosis, afecta principalmente a los niños y es potencialmente fatal. Objetivo: Exponer la caracterización clínico-epidemiológica de la leishmaniosis visceral en población pediátrica y su respuesta terapéutica. Métodos: Se realizó un estudio retrospectivo, longitudinal y descriptivo en el Hospital Italiano, Ciudad de Djibouti en el período septiembre 2016-agosto 2017. El universo lo conformaron 166 menores de 15 años que ingresaron con diagnóstico de fiebre prolongada sin foco de localización, la muestra fue de 22 niños con diagnóstico confirmado de leishmaniosis visceral. La información se obtuvo de las historias clínicas. Se operacionalizaron 20 variables: sociodemográficas, clínicas, analíticas, terapéuticas y evolutivas. Se utilizó el procesador Epidat 3.1. Los resultados se expresaron en valores absolutos y porcentajes. Resultados: Se diagnosticó leishmaniosis visceral en 13,2 por ciento de niños hospitalizados por fiebre prolongada, 90,9 por ciento de procedencia rural y 59,1 por ciento desnutridos. El 77,3 por ciento de los casos recibió antimoniales, 90,9 por ciento tuvo estadía hospitalaria mayor de 21 días y el 36,4 por ciento se complicó con neumonía. Conclusiones: La leishmaniosis visceral es una entidad relativamente frecuente en niños admitidos por fiebre prolongada en el Hospital Italiano, predominan los varones desnutridos, mayores de cinco años de edad, procedentes de zonas rurales. La fiebre y la esplenomegalia son manifestaciones clínicas constantes, la anemia y la leucopenia los principales hallazgos de laboratorio. La aplicación de antimoniales es el tratamiento electivo, con larga estadía hospitalaria y la neumonía es la complicación más frecuente(AU)

Introduction: Visceral leishmaniasis is the most severe clinical form of leishmaniasis that mainly affects children and is potentially fatal. Objective: To explain the clinical-epidemiological characterization of visceral leishmaniasis in the pediatric population and its therapeutic response. Methods: It was conducted a retrospective, longitudinal and descriptive study in the Italian Hospital, Djibouti City in the period from September 2016 to August 2017. The sample group was formed by 166 children under 15 years old that were admitted with a diagnosis of prolonged fever without localization focus and the sample was of 22 children with confirmed diagnosis of visceral leishmaniasis. The information was obtained from the clinical records. Twenty variables were operationalized: sociodemographic, clinical, analytical, therapeutic and evolutive ones. Epidat 3.1 proccessor was used. The results were expressed in absolute values and percentages. Results: Visceral leishmaniasis was diagnosed in 13.2 percent children that were admitted in hospital due to prolonged fever, 90.9 percent of them were from rural areas and 59.1 percent were undernourished. 77,3 percent of the cases had antimonial treatment, 90.9 percent had hospital stay for more than 21 days and the 36.4 percent had complications due to pneumonia. Conclusions: Visceral leishmaniasis is a relatively frequent entity in children admitted in the Italian Hospital due to prolonged fever with a predominance of undernourished males, older that five years and from rural areas. Fever and splenomegaly are constant clinical manifestations, and anemia and leucopenia are the main laboratory findings. The use of antimonials is the election treatment with long hospital stay, and pneumonia is the most frequent complication(AU)

FLI1 gene influences lesion size and skin test may predict therapeutic response in cutaneous leishmaniasis.

Genes associated with wound healing have been shown to be risk factors for cutaneous leishmaniasis (CL) which is caused by Leishmania braziliensis. In this study, we examined whether the genes previously associated with CL influenced the clinical outcome. Patients were genotyped and retrospectively classified as responders, who were cured with a single course of pentavalent antimony (Sbv), or as refractories, who did not respond to Sbv. Patients characterised as responders showed a stronger response to the leishmanin skin test (LST) when compared to the refractory subjects (p = 0.0003). Furthermore, we observed an association between the FLI1 CC genotype and an increased size of ulcers (p = 0.0170). We suggest that the leishmanin skin test may be a predictive tool for therapeutic outcome and reinforce FLI1 as a potential influencer of susceptibility and lesion size in CL.

Arundo donax L. stem-derived biochar increases As and Sb toxicities from nonferrous metal mine tailings.

Toxic metal(loid)s released from tailing residues of mining operations have become a global issue with regard to environmental impacts. Biochar derived from the agriculture waste is considered as a cost-effective and stable material, which could be applied for remediation of sites contaminated with toxic metal(loid)s. In the present study, tailings were amended for 90 days with increasing concentrations of Arundo donax L. stem-derived biochar (ASBC; at 0, 1, 3, and 5%). The 7-day wheat seed germination toxicity test was then used to assess the bioavailability of toxicants in aqueous leachates of the biochar-amended tailing samples. Concentrations of As, Cd, Cu, Pb, and Sb in leachates and the Community Bureau of Reference chemical fractions were determined using ICP-OES. The results indicated that tailing leachates were phytotoxic, an effect that was partially decreased due to increasing concentrations of ASBC, with maximum effects (∼47% of tailing phytotoxicity) occurring at 3% ASBC. Results of further fractionation analyses indicated that increasing concentrations of ASBC amendment decreased the mobile fractions of Cd, Cu, and Pb in tailing samples, but increased the mobilities of As and Sb. A novel approach using the relative toxicity index (= sum of toxicities of individual potentially toxic elements) indicated that the toxicity of the tailings decreased when As was not present, since As decreased the biochar-reduced toxicity. Our results suggest that the ability of using biochar to decrease toxicity in tailings (by sequestration of cationic metals such as Cd, Cu, and Pb) is limited by its inability to immobilize oxyanionic metalloids such as As and Sb.

Clinical features and therapeutic response in adult and pediatric patients with American tegumentary leishmaniasis in Rio de Janeiro.

BACKGROUND: American tegumentary leishmaniasis (ATL) is a neglected disease with wide territorial distribution. Knowledge is scarce in children and adolescents. This study aims to compare the clinical features and response to antimony treatment in pediatric and adult patients with cutaneous leishmaniasis. METHODS: A retrospective cohort study was performed with 659 patients who attended a reference centre in Rio de Janeiro, Brazil, from 2000 to 2015. The pediatric cohort consisted of 131 (20%) patients and the adult cohort consisted of 528 (80%) patients. RESULTS: The epidemiological profile, antimony therapeutic response and incidence of adverse events (AE) were different in the pediatric cohort compared with the adult cohort. Mucosal form was less frequent in the pediatric cohort (RR:0.49, p=0.011). Lesions in the head, neck and trunk were more frequent in the pediatric cohort (RR:1.49, p=0.043). The effectiveness of antimony treatment was superior in the pediatric cohort (88.3% vs 76.6%) with a shorter healing time (RR:0.49, p=0.009). Pediatric patients had lower proportions of moderate to severe AE compared with adults (RR:0.45, p=0.027). Clinical AE predominated in the adult cohort (RR:0.40, p=0.000) and laboratory AE in the pediatric cohort (RR:1.50, p=0.023). CONCLUSIONS: This study adds to the body of knowledge on differences that exist between different age groups in ATL.