Therapeutic effect of mefloquine on Schistosoma mansoni in experimental infection in mice

Evaluation of the prophylactic and therapeutic efficacies of mucus and tissue nucleoproteins extracted from Biomphalaria alexandrina snails on schistosomiasis mansoni

Schistosomiasis is a neglected tropical disease with considerable morbidity. The lone effective drug, praziquantel (PZQ), is showing emergence of drug resistance hence, searching for new supportive treatment is crucial. This study aimed to evaluate the efficacy of mucus and nucleoproteins (NPs) extracted from Biomphalaria alexandrina (B. alexandrina) snails on miracidia, cercariae and Schistosoma mansoni (S. mansoni) adults in vitro and assess their experimental in vivo effect through parasitological, histopathological, and biochemical parameters. The in vivo study included 90 male Swiss albino mice. Mice were grouped into 9 groups; G1-G5 were infected and treated with; GI: PZQ, GII: mucus, GIII: combined PZQ and mucus, GIV: NPs, GV: combined PZQ and NPs. Control groups; C1: Non infected non treated (negative control), C2: Infected non treated (positive control), C3: Non infected mucus treated and C4: Non infected NPs treated. The in vitro study proved that the mucus had a better lethal effect on cercariae than miracidia, while NPs had better lethal effect on miracidia. The mucus lethal effect on adults surpassed the NPs as 100% and 60%, respectively. The in vivo study proved that the combined NPs or mucus with PZQ added to the effect of individual PZQ resulting in 100% total worm burden (TWB) reduction. As regard oxidative stress markers, the lowest level of nitric oxide (NO) was shown with combined PZQ and NPs. While, the highest glutathione (GSH) level was produced by individual PZQ. The study concluded that mucus and NPs of B. alexandrina had cercaricidal, miracidicidal and anti-schistosomal effect in vitro and that their combination could be considered a contribution to PZQ potentiality in vivo.

Antimalarial artesunate-mefloquine versus praziquantel in African children with schistosomiasis: an open-label, randomized controlled trial

Schistosomiasis treatment entirely relies on a single drug, praziquantel, prompting research into alternative therapeutics. Here we evaluated the efficacy and safety of the antimalarial combination artesunate-mefloquine for the treatment of schistosomiasis in a proof-of-concept, pragmatic, open-label, randomized controlled trial in primary schools of six villages endemic for schistosomiasis in northern Senegal. Children (6-14 years) were eligible if Schistosoma eggs were detected by microscopy in urine and/or stool. In total, 726 children were randomized 1:1 to praziquantel (standard care: 40 mg kg-1 single dose; n = 364) or to artesunate-mefloquine (antimalarial dosage: artesunate 4 mg kg-1 and mefloquine 8 mg kg-1 daily for three consecutive days; n = 362). Eight children not meeting the inclusion criteria were excluded from efficacy analysis. Median age of the remaining 718 participants was 9 years; 399 (55.6%) were male, and 319 (44.4%) female; 99.3% were infected with Schistosoma haematobium and 15.2% with S. mansoni. Primary outcomes were cure rate, assessed by microscopy, and frequency of drug-related adverse effects of artesunate-mefloquine versus praziquantel at 4 weeks after treatment. Cure rate was 59.6% (208/349) in the artesunate-mefloquine arm versus 62.1% (211/340) in the praziquantel arm. The difference of -2.5% (95% confidence interval (CI) -9.8 to 4.8) met the predefined criteria of noninferiority (margin set at 10%). All drug-related adverse events were mild or moderate, and reported in 28/361 children receiving artesunate-mefloquine (7.8%; 95% CI 5.4 to 11.0) versus 8/363 (2.2%; 95% CI 1.1 to 4.3) receiving praziquantel (P < 0.001). Artesunate-mefloquine at antimalarial dosage was moderately safe and noninferior to standard-care praziquantel for the treatment of schistosomiasis, predominantly due to S. haematobium. Multicentric trials in different populations and epidemiological settings are needed to confirm these findings. ClinicalTrials.gov identifier: NCT03893097 .

Drug associations as alternative and complementary therapy for neglected tropical diseases

The present paper aims to establish different treatments for neglected tropical disease by a survey on drug conjugations and possible fixed-dose combinations (FDC) used to obtain alternative, safer and more effective treatments. The source databases used were Science Direct and PubMed/Medline, in the intervals between 2015 and 2021 with the drugs key-words or diseases, like "schistosomiasis", "praziquantel", "malaria", "artesunate", "Chagas' disease", "benznidazole", "filariasis", diethylcarbamazine", "ivermectin", " albendazole". 118 works were the object of intense analysis, other articles and documents were used to increase the quality of the studies, such as consensuses for harmonizing therapeutics and historical articles. As a result, an effective NTD control can be achieved when different public health approaches are combined with interventions guided by the epidemiology of each location and the availability of appropriate measures to detect, prevent and control disease. It was also possible to verify that the FDCs promote a simplification of the therapeutic regimen, which promotes better patient compliance and enables a reduction in the development of parasitic resistance, requiring further studies aimed at resistant strains, since the combined APIs usually act by different mechanisms or at different target sites. In addition to eliminating the process of developing a new drug based on the identification and validation of active compounds, which is a complex, long process and requires a strong long-term investment, other advantages that FDCs have are related to productive gain and gain from the industrial plant, which can favor and encourage the R&D of new FDCs not only for NTDs but also for other diseases that require the use of more than one drug.

Evaluation of Artesunate-mefloquine as a Novel Alternative Treatment for Schistosomiasis in African Children (SchistoSAM): protocol of a proof-of-concept, open-label, two-arm, individually-randomised controlled trial

INTRODUCTION

Alternative drugs and diagnostics are needed for the treatment and control of schistosomiasis. The exclusive use of praziquantel (PZQ) in mass drug administration programmes may result in the emergence of drug resistance. PZQ has little activity against Schistosoma larvae, thus reinfection remains a problem in high-risk communities. Furthermore, the insufficient sensitivity of conventional microscopy hinders therapeutic response assessment. Evaluation of artesunate-mefloquine (AM) as a Novel Alternative Treatment for Schistosomiasis in African Children (SchistoSAM) aims to evaluate the safety and efficacy of the antimalarial combination artesunate-mefloquine, re-purposed for the treatment of schistosomiasis, and to assess the performance of highly sensitive novel antigen-based and DNA-based assays as tools for monitoring treatment response.

METHODS AND ANALYSIS

The SchistoSAM study is an open-label, two-arm, individually randomised controlled non-inferiority trial, with a follow-up of 48 weeks. Primary school-aged children from the Richard Toll district in northern Senegal, an area endemic for Schistosoma mansoni and Schistosoma haematobium, are allocated to the AM intervention arm (3-day courses at 6-week intervals) or the PZQ control arm (single dose of 40 mg/kg). The trial's primary endpoints are the efficacy (cure rate (CR), assessed by microscopy) and safety (frequency and pattern of drug-related adverse events) of one AM course versus PZQ at 4 weeks after treatment. Secondary endpoints include (1) cumulative CR, egg reduction rate and safety after each additional course of AM, and at weeks 24 and 48, (2) prevalence and severity of schistosomiasis-related morbidity and (3) malaria prevalence, incidence and morbidity, both after 24 and 48 weeks. CRs and intensity reduction rates are also assessed by antigen-based and DNA-based diagnostic assays, for which performance for treatment monitoring is evaluated.

ETHICS AND DISSEMINATION

Ethics approval was obtained both in Belgium and Senegal. Oral assent from the children and signed informed consent from their legal representatives was obtained, prior to enrolment. The results will be disseminated in peer-reviewed journals and at international conferences.

TRIAL REGISTRATION NUMBER

NCT03893097; pre-results.

Therapeutic Efficacy of Albendazole and Mefloquine Alone or in Combination Against Early and Late Stages of Trichinella Spiralis Infection in Mice

This study aimed to determine the effectiveness of mefl oquine alone or combined with albendazole in reduced doses against T. spiralis infection. One hundred and twenty albino mice were orally infected with 200 T. spiralis larvae/mouse. Drugs were administered during the enteral phase on days 1 to 3 and on the chronic phase on days 35 to 37 post-infection, and mice were sacrificed, respectively, at days 7 or 48 post-infection to count mature intestinal worms or encysted muscle larvae. The effect of the treatment on the histology of the target organs of each phase, intestine and diaphragm, was also evaluated. A signifi cant decrease in intestinal worms was found in all treated groups relative to the untreated control group at a peak of 93.7% in the combination albendazole-mefl oquine group. Results in all treated groups demonstrated a signifi cant decrease in muscle larvae relative to untreated control groups, achieving 86.2 % in the combined albendazole-mefl oquine group. There was a marked improvement in the intestinal and muscular architecture in all treated groups compared to the non-treated control group. Notably, the albendazole-mefl oquine group showed an almost complete recovery. The combined albendazole-mefl oquine low dose regimen had the highest effect on reducing parasite burden and restoring normal histological architecture.

Evaluation of possible prophylactic and therapeutic effect of mefloquine on experimental cryptosporidiosis in immunocompromised mice

Cryptosporidiosis is an imperative global health concern. Unfortunately, Nitazoxanide (NTZ) (the nowadays drug of choice) is not effective in treatment of immunocompromised patients. We aimed to assess the possible anti-cryptosporidial prophylactic and therapeutic effects of Mefloquine (MQ) on infected immunosuppressed murine models. Mice were divided into five groups; GI: received Mefloquine (400 mg/kg/day), GII: received NTZ (100 mg/kg/bid), GIII: received a combination, half dose regimen of both drugs, GIV: infected untreated and GV: non-infected untreated. Each treated group was divided into three subgroups; Ga prophylaxis (PX), thereafter infection, Gb first and Gc second treatment doses. Assessment was done by parasitological, histopathological and serological techniques. A significant oocyst clearance was detected in all prophylactically treated groups. GIa showed 77% reduction of the mean oocyst count in stool while GIb and GIIIc showed100% oocyst clearance. Histopathologically, the ileocecal sections from GIV showed loss of brush borders with marked villous atrophy. GIa induced a moderate improvement of those pathological changes. Moreover, the villi in GIb and GIIIc retained their normal appearance with minimal inflammatory cells. Serum interferon gamma levels showed highly significant increases in GI&GIII compared to GIV while a non-significant increase was observed in GIIa only. On the contrary, serum interleukin-17 levels showed a highly significant down-regulation in all treated groups in comparison to GIV. This study proved a marvelous effect of MQ-PX on cryptosporidiosis in immunosuppressed mice and thus it could be introduced as one of the most promising re-purposed prophylactic and therapeutic anti-cryptosporidial agents.

Heterogeneity in the in vitro susceptibility of Loa loa microfilariae to drugs commonly used in parasitological infections

Background

Co-infection with loiasis remains a potential problem in control programs targeting filarial infections. The effects of many anti-parasitic drugs often administered to Loa loa infected people are not well documented. This study compared the in vitro activity of several of these drugs on the viability of L. loa microfilariae (mf).

Methods

Human strain L. loa mf were isolated from baboon blood using iso-osmotic Percoll gradient, and cultured in RPMI 1640/10% FBS with antimalarial drugs (mefloquine, amodiaquine, artesunate, chloroquine and quinine), anthelmintics (ivermectin, praziquantel, flubendazole and its reduced and hydrolyzed metabolites), two potential trypanocidal agents (fexinidazole and Scynexis-7158) and the anticancer drug imatinib. The drug concentrations used varied between 0.156 μg/ml and 10 μg/ml. Mf motility (CR₅₀ = 50% immotility) and a metabolic viability assay (MTT) were used to assess the effects of these drugs on the parasites.

Results

Mf in control cultures showed only a slight reduction in motility after 5 days of culture. Active inhibition of Loa loa motility was seen with mefloquine and amodiaquine (CR₅₀ values of 3.87 and 4.05 μg/ml, respectively), immobilizing > 90% mf within the first 24 hours: mefloquine killed the mf after 24 hours of culture at concentrations ≥ 5 μg/ml. SCYX-7158 also induced a concentration-dependent reduction in mf motility, with > 50% reduction in mf motility seen after 5 days at 10 μg/ml. The anticancer drug imatinib reduced mf motility at 10 μg/ml from the first day of incubation to 55% by day 5, and the reduction in motility was concentration-dependent. Praziquantel and fexinidazole were inactive, and FLBZ and its metabolites, as well as ivermectin at concentrations > 5 μg/ml, had very minimal effects on mf motility over the first 4 days of culture.

Conclusions

The considerable action of the anti-malarial drugs mefloquine and amodiaquine on Loa mf in vitro highlights the possibility of repurposing the existing anti-infectious agents for the development of drugs against loiasis. The heterogeneity in the activity of anti-parasitic agents on Loa loa mf supports the need for further investigation using animal models of loiasis.

Electronic supplementary material

The online version of this article (10.1186/s13071-018-2799-3) contains supplementary material, which is available to authorized users.

Hybrid feature extraction techniques for microscopic hepatic fibrosis classification

Chronic liver diseases' hallmark is the fibrosis that results in liver function failure in advanced stages. One of the serious parasitic diseases affecting the liver tissues is schistosomiasis. Immunologic reactions to Schistosoma eggs leads to accumulation of collagen in the hepatic parenchyma causing fibrosis. Thus, monitoring and reporting the staging of the histopathological information related to liver fibrosis are essential for accurate diagnosis and therapy of the chronic liver diseases. Automated assessment of the microscopic liver tissue images is an essential process. For accurate and timeless assessment, an automated image analysis and classification of different stages of fibrosis can be employed as an efficient procedure. In this work, granuloma stages, namely cellular, fibrocellular, and fibrotic granulomas along with normal liver samples were classified after features extraction. In this work, a new hybrid combination of statistical features with empirical mode decomposition (EMD) is proposed. These combined features are further classified using the back-propagation neural network (BPNN). A comparative study of the used classifier with the support vector machine is also conducted. The comparative results established that the BPNN achieved superior accuracy of 98.3% compared to the linear SVM, quadratic SVM, and cubic SVM that provided 85%, 84%, and 80%; respectively. In conclusion, this work is of special value that provides promising results for early prediction of the liver fibrosis in schistosomiais and other fibrotic liver diseases in no time with expected better prognosis after treatment.

Antischistosomal agents: state of art and perspectives

Praziquantel has remained the drug of choice for schistosomiasis chemotherapy for almost 40 years. The pressing need to develop a new antischistosomal drug may necessitate exploring and filtering chemotherapeutic history to search for the most promising ones. In this context, this review attempts to summarize all progress made in schistosomiasis chemotherapy from the early 20th century (mid-1910s) to 2016. We gathered almost 100 compounds providing information on therapeutic action, specifically covering at least first in vivo studies in animal model and in vitro. Pharmacokinetic and toxicity profiles of antischistosomal agents were also described. Preclinical studies indicate a handful of promising future candidates.

Controlling schistosomiasis with praziquantel: How much longer without a viable alternative?

The current approach of morbidity control of schistosomiasis, a helminth disease of poverty with considerable public health and socioeconomic impact, is based on preventive chemotherapy with praziquantel. There is a pressing need for new drugs against this disease whose control entirely depends on this single drug that has been widely used over the past 40 years. We argue that a broader anthelminthic approach supplementing praziquantel with new antischistosomals targeting different parasite development stages would not only increase efficacy but also reduce the risk for drug resistance. Repositioning drugs already approved for other diseases provides a shortcut to clinical trials, as it is expected that such drugs rapidly pass the regulatory authorities. The antischistosomal properties of antimalarial drugs (e.g., semisynthetic artemisinins, synthetic trioxolanes, trioxaquines and mefloquine) and of drugs being developed or registered for other purposes (e.g., moxidectin and miltefosin), administered alone or in combination with praziquantel, have been tested in the laboratory and clinical trials. Another avenue to follow is the continued search for new antischistosomal properties in plants. Here, we summarise recent progress made in schistosomiasis chemotherapy, placing particular emphasis on repositioning of existing drugs against schistosomiasis.