Antiparasitic therapy

Synthesis and anthelmintic activity of novel thiosemicarbazide and 1,2,4-triazole derivatives: In vitro, in vivo, and in silico study

INTRODUCTION

Intestinal parasitic infections are neglected diseases and, due to the increasing resistance of parasites to available drugs, they pose an increasing therapeutic challenge. Therefore, there is a great need for finding new compounds with antiparasitic activity.

OBJECTIVES

In this work, new thiosemicarbazide and 1,2,4-triazole derivatives were synthesized and tested for their anthelmintic activity.

METHODS

The synthesis was carried out by classical methods of organic chemistry. Anthelmintic activity tests were carried out in vitro (Rhabditis sp., Haemonchus contortus, Strongylidae sp.) in vivo (Heligmosomoides polygyrus/bakeri), and in silico analysis was performed.

RESULTS

Quinoline-6-carboxylic acid derivative compounds were designed and synthesized. The highest activity in the screening tests in the Rhabditis model was demonstrated by compound II-1 with a methoxyphenyl substituent LC50 = 0.3 mg/mL. In the next stage of the research, compound II-1 was analyzed in the H. contortus model. The results showed that compound II-1 was active and had ovicidal (percentage of dead eggs > 45 %) and larvicidal (percentage of dead larvae > 75 %) properties. Studies in the Strongylidae sp. model confirmed the ovicidal activity of compound II-1 (percentage of dead eggs ≥ 55 %). In vivo studies conducted in the H. polygyrus/bakeri nematode model showed that the number of nematodes decreased by an average of 30 % under the influence of compound II-1. In silico studies have shown two possible modes of action of compound II-1, i.e. inhibition of tubulin polymerization and SDH. The test compound did not show any systemic toxic effects. Its influence on drug metabolism related to the activity of cytochrome CYP450 enzymes was also investigated.

CONCLUSION

The results obtained in the in vitro, in vivo, and in silico studies indicate that the test compound can be described as a HIT, which in the future may be used in the treatment of parasitic diseases in humans and animals.

Single and combination treatment of Toxoplasma gondii infections with a bumped kinase inhibitor and artemisone in vitro and with artemiside in experimentally infected mice

In previous studies, the artemisinin derivatives artemisone, its pro-drug artemiside and the bumped-kinase inhibitor BKI-1748 were effective against T. gondii via different modes of action. This suggests that they may act synergistically resulting in improved efficacies in vitro and in vivo. To test this hypothesis, the compounds were applied alone and in combination to T. gondii infected human fibroblast host cells in order to determine their inhibition constants and effects on cellular ultrastructure. In addition, the efficacy of either single- or combined treatments were assessed in an acute TgShSp1-oocyst infection model based on CD1 outbred mice. Whereas the IC50 of the compounds in combination (42 nM) was close to the IC50 of BKI-1748 alone (46 nM) and half of the IC50 of artemisone alone (92 nM), the IC90 of the combination was half of the values found with the single compounds (138 nM vs. ca. 270 nM). Another indication for synergistic effects in vitro were distinct alterations of the cellular ultrastructure of tachyzoites observed in combination, but not with the single compounds. These promising results could not be reproduced in vivo. There was no decrease in number of T. gondii positive brains by either treatment. However, the levels of infection in these brains, i. e. the number of tachyzoites, was significantly decreased upon BKI-1748 treatment alone, and the combination with artemiside did not produce any further decrease. The treatment with artemiside alone had no significant effects. A vertical transmission model could not be established since artemiside strongly interfered with pregnancy and caused abortion. These results show that is difficult to extrapolate from promising in vitro results to the situation in vivo.

Nematicidal Characterization of Solanum nigrum and Mentha arvensis Leaf Extracts Using Caenorhabditis elegans as a Model Organism

Considering foremost global issues instigated by parasitic nematodes, Solanum nigrum (S. nigrum) and Mentha arvensis (M. arvensis) nematicidal potential at the gene level has been explored herein. Methanol, ethyl acetate, chloroform, n-hexane, and distilled water were used for extract preparation. Caenorhabditis elegans (C. elegans) was used as the model organism. Nematicidal and anti-egg hatching assays, fluorescence microscopy, and quantitative real-time PCR were done. S. nigrum chloroform (LD₅₀ = 1.21 mg/mL) and M. arvensis methanol (LD₅₀ = 2.47 mg/mL) extracts exhibited excellent nematicidal potential. Both plants showed potent anti-egg hatching activity (1 mg/mL). S. nigrum methanol and M. arvensis ethyl acetate extracts showed high apoptotic effect in muscles, gonads, and uterus (eggs). Stress genes, that is, gst-4, hsp-16.2, and gpdh-1 were highly expressed in affected C. elegans (treated with S. nigrum and M. arvensis leaf extracts) when compared with normal C. elegans. Phytochemicals and bioactive compounds present in plants may be the major cause of their excellent nematicidal potential, which further confirmed that both plants could be an alternative candidate(s) for novel broad-scale anthelmintic drug(s).

SARS-CoV-2 Spike protein activates TMEM16F-mediated platelet procoagulant activity

Thrombosis of the lung microvasculature is a characteristic of COVID-19 disease, which is observed in large excess compared to other forms of acute respiratory distress syndrome and thus suggests a trigger for thrombosis that is endogenous to the lung. Our recent work has shown that the SARS-CoV-2 Spike protein activates the cellular TMEM16F chloride channel and scramblase. Through a screening on >3,000 FDA/EMA approved drugs, we identified Niclosamide and Clofazimine as the most effective molecules at inhibiting Spike-induced TMEM16 activation. As TMEM16F plays an important role in stimulating the procoagulant activity of platelets, we investigated whether Spike directly affects platelet activation and pro-thrombotic function and tested the effect of Niclosamide and Clofazimine on these processes. Here we show that Spike, present either on the virion envelope or on the cell plasma membrane, promotes platelet activation, adhesion and spreading. Spike was active as a sole agonist or, even more effectively, by enhancing the function of known platelet activators. In particular, Spike-induced a marked procoagulant phenotype in platelets, by enhancing Ca²⁺ flux, phosphatidylserine externalization on the platelet outer cell membrane, and thrombin generation. Eventually, this increased thrombin-induced clot formation and retraction. Both Niclosamide and Clofazimine blocked this Spike-induced procoagulant response. These findings provide a pathogenic mechanism to explain lung thrombosis-associated with severe COVID-19 infection. We propose that Spike, present in SARS-CoV-2 virions or exposed on the surface of infected cells in the lungs, enhances the effects of inflammation and leads to local platelet stimulation and subsequent activation of the coagulation cascade. As platelet TMEM16F is central in this process, these findings reinforce the rationale of repurposing Niclosamide for COVID-19 therapy.

Diarrhea due to parasites: a short, updated point of view from the clinical setting

Diarrhea represents a common manifestation of several gastrointestinal diseases. Infectious agents are the most common causes of diarrhea in developing countries, where the inadequate sanitation and hygiene are prevalent. In these countries, the scarcity of preventive measures as well as the limited health resources cause a substantial increase in incidence, morbidity and mortality due to infectious diseases, including diarrhea. Currently, with the availability of rapid and inexpensive air transportation millions of people travel for tourism, work and immigration from developing countries to industrialized countries and vice versa. This leads to a high number of imported pathogens such as parasites causing infectious diarrhea. Importantly, while most cases of parasitic diarrhea are short, mild and self-limited, other cases may be associated with chronic diarrhea and serious morbidity and mortality. The aim of the current review was to provide an update, from a clinician's point of view, of the main parasites causing diarrhea, with a focus on their diagnosis and management in the clinical setting.

Evaluation of Anthelmintic and Anti-Inflammatory Activity of 1,2,4-Triazole Derivatives

Parasitic diseases, caused by intestinal helminths, remain a very serious problem in both human and veterinary medicine. While searching for new nematicides we examined a series of 1,2,4-triazole derivatives 9–22, obtained during reactions of N³-substituted amidrazones with itaconic anhydride. Two groups of compounds, 9–16 and 17–22, differed in the position of the double bond on the methacrylic acid moiety. The toxicity of derivatives 9–22 and the anti-inflammatory activity of 12 and 19–22 were studied on peripheral blood mononuclear cells (PBMC). Antiproliferative activity of compounds 12 and 19–22 was tested cytometrically in PBMC cultures stimulated by phytohemagglutinin. The influence of derivatives 12 and 19–22 on the TNF-α, IL-6, IL-10 and IFN-γ production was determined by ELISA in lipopolysaccharide-stimulated PBMC cultures. Anthelmintic activity of compounds 10–22 was studied in the Rhabditis sp. nematodes model. Most compounds (11–22) proved to be non-toxic to human PBMC. Derivatives 19–22 showed anti-inflammatory activity by inhibiting the proliferation of lymphocytes. Moreover, compounds 12 and 19–22 significantly reduced the production of TNF-α and derivatives 19–21 decreased the level of INF-γ. The strongest anti-inflammatory activity was observed for compound 21. Compounds 12 and 14 demonstrated anthelmintic activity higher than albendazole and may become promising candidates for anthelmintic drugs.

An Overview of Mucosa-Associated Protozoa: Challenges in Chemotherapy and Future Perspectives

Parasitic infections caused by protozoans that infect the mucosal surfaces are widely neglected worldwide. Collectively, Entamoeba histolytica, Giardia lamblia, Cryptosporidium spp. and Trichomonas vaginalis infect more than a billion people in the world, being a public health problem mainly in developing countries. However, the exact incidence and prevalence data depend on the population examined. These parasites ultimately cause pathologies that culminate in liver abscesses, malabsorption syndrome, vaginitis, and urethritis, respectively. Despite this, the antimicrobial agents currently used to treat these diseases are limited and often associated with adverse side effects and refractory cases due to the development of resistant parasites. The paucity of drug treatments, absence of vaccines and increasing problems of drug resistance are major concerns for their control and eradication. Herein, potential candidates are reviewed with the overall aim of determining the knowledge gaps and suggest future perspectives for research. This review focuses on this public health problem and focuses on the progress of drug repositioning as a potential strategy for the treatment of mucosal parasites.

Targeting Clostridioides difficile: New uses for old drugs

Clostridioides difficile bacteria can cause life-threatening diarrhea and colitis owing to limited treatment options and unacceptably high recurrence rates among infected patients. This necessitates the development of alternative routes for C. difficile treatment. Drug repurposing with new indications represents a proven shortcut. Here, we present a refined focus on 16 FDA-approved drugs that would be suitable for further development as potential anti-C. difficile drugs. Of these drugs, clinical trials have been conducted on five currently used drugs; however, ursodeoxycholic acid is the only drug to enter Phase IV clinical trials to date. Thus, drug repurposing promotes the study of mechanistic and therapeutic strategies, providing new options for the development of next-generation anti-C. difficile agents.

Discovery of Cinnamylidene Derivative of Rhodanine with High Anthelmintic Activity against Rhabditis sp

The treatment of parasitic infections requires the application of chemotherapy. In view of increasing resistance to currently in-use drugs, there is a constant need to search for new compounds with anthelmintic activity. A series of 16 cinnamylidene derivatives of rhodanine, including newly synthesized methoxy derivatives (1-11) and previously obtained chloro, nitro, and diethylamine derivatives (12-16), was investigated towards anthelmintic activity. Compounds (1-16) were evaluated against free-living nematodes of the genus Rhabditis sp. In the tested group of rhodanine derivatives, only compound 2 shows very high biological activity (LC50 = 0.93 µg/µL), which is higher than the reference drug albendazole (LC50 = 19.24 µg/µL). Crystal structures of two compounds, active 2 and inactive 4, were determined by the X-ray diffraction method to compare molecular geometry and search for differences responsible for observed biological activity/inactivity. Molecular modelling and selected physicochemical properties prediction were performed to assess the potential mechanism of action and applied in the search for an explanation as to why amongst all similar compounds only one is active. We can conclude that the tested compound 2 can be further investigated as a potential anthelmintic drug.

Genus Zanthoxylum as Sources of Drugs for Treatment of Tropical Parasitic Diseases

The tropical parasitic infections account to more than 2 billion infections and cause substantial morbidity and mortality, and accounts to several million deaths every year. Majorly parasitic infections in humans and animals are caused by protozoa and helminths. Chronic infections in host can cause retardation, impairment of cognitive skills, development in young children and weaken the immune system. The burden is felt to a greater extent in developing countries due to poverty, inaccessibility to medicines and resistance observed to drugs. Thus, human health continues to be severely harmed by parasitic infections. Medicinal plants have received much attention as alternative sources of drugs. Zanthoxylum genus has been used ethnobotanically as an antiparasitic agent and the phytoconstituents in Zanthoxylum, show wide variety of chemical substances with proven pharmacological actions such as alkaloids (isoquinolines and quinolines responsible for antitumor activity, antimalarial, antioxidant and antimicrobial actions), lignans, coumarins (antibacterial, antitumour, vasodilatory and anticoagulant activities), alkamide (strong insecticidal properties, anthelminthic, antitussive and analgesic anti antimalarial property). Therefore, this article is an attempt to review the existing literature that emphasizes on potential of genus Zanthoxylum as source of lead compounds for treatment of parasitic diseases.

Anthelmintic potency of Rumex crispus L. extracts against Caenorhabditis elegans and non-targeted identification of the bioactive compounds

Traditional healers and ethnoveterinary therapists use several medicinal plants, such as Rumex crispus L., to treat endoparasite infections. R. crispus has been established by researchers to be effective agasint a few parasitic worms. In this study, we evaluated the potency of R. crispus extracts on the model organism, Caenorhabditis elegans and the bioactive compounds of the extracts were also identified. The solvent extracts of R. crispus were tested against C. elegans for up to 72 h. The effect of the extracts on C. elegans was examined using light microscopy (LM) and scanning electron microscopy (SEM). LM and SEM analysis showed damage on the body wall, reduced body and slight modifications of the nematode organs. The lethality test reveals a significant reduction in the viability of the nematode with the water extract of leaf (LF-WAE), among others, having the strongest potency against the nematode, with 83% lethality. Anlysis done with Fourier-transform infrared spectroscopy (FTIR) spectra reveals various characteristic vibration bands and fingerprint bands at 3400–600 cm⁻¹, identifying phenols, organic acids, aromatics, amines, among others in the plant. The compounds were identified with liquid chromatography-mass spectrometry (LC-MS), under the categories of flavonoids, steroidal alkaloids and proanthocyanidin. In conclusion, this study confirmed that R. crispus has anthelmintic potential, using standardised C. elegans models as a tool and suggests that there could be novel compounds yet to be explored in the studied plant that could be of great benefit to livestock and humans.

Resolution of systemic complications in Schistosoma mansoni-infected mice by concomitant treatment with praziquantel and Schisandrin B

Schistosomiasis is a tropical parasitic disease, in which the major clinical manifestation includes hepatosplenomegaly, portal hypertension, and organs fibrosis. Clinically, treatment of schistosomiasis involves the use of praziquantel (PZQ) and supportive care, which does not improve the patient's outcome as liver injuries persist. Here we show the beneficial effects of using PZQ in combination with Schisandrin B (Sch B). Concomitant treatment with PZQ and Sch B resulted in a significant improvement of hepatosplenomegaly and fibrosis, compared with single-agent treatment. We also demonstrated that PZQ-Sch B treatment ameliorates injuries in the lungs and intestine better than the sole use of PZQ or Sch B. In addition, PZQ-Sch B treatment improves the survival of S. mansoni-infected mice, and the treatment combination yields better therapeutic outcomes, as indicated by a partial improvement in neurological function. These results were accompanied by a reduction in neurological injuries. Collectively, we suggest that PZQ-Sch B concomitant therapy may be useful to alleviate schistosomiasis-associated liver injuries and prevent systemic complications.

Streptomyces, Greek Habitats and Novel Pharmaceuticals: A Promising Challenge

Bacteria of the genus Streptomyces produce a very large number of secondary metabolites, many of which are of vital importance to modern medicine. There is great interest in the discovery of novel pharmaceutical compounds derived from strepomycetes, since novel antibiotics, anticancer and compounds for treating other conditions are urgently needed. Greece, as proven by recent research, possesses microbial reservoirs with a high diversity of Streptomyces populations, which provide a rich pool of strains with potential pharmaceutical value. This review examines the compounds of pharmaceutical interest that have been derived from Greek Streptomyces isolates. The compounds reported in the literature include antibiotics, antitumor compounds, biofilm inhibitors, antiparasitics, bacterial toxin production inhibitors and antioxidants. The streptomycete biodiversity of Greek environments remains relatively unexamined and is therefore a very promising resource for potential novel pharmaceuticals.

Molecular Docking and Dynamics Simulation Revealed Ivermectin as Potential Drug against Schistosoma-Associated Bladder Cancer Targeting Protein Signaling: Computational Drug Repositioning Approach

Urogenital schistosomiasis is caused by Schistosoma haematobium (S. haematobium) infection, which has been linked to the development of bladder cancer. In this study, three repurposing drugs, ivermectin, arteether and praziquantel, were screened to find the potent drug-repurposing candidate against the Schistosoma-associated bladder cancer (SABC) in humans by using computational methods. The biology of most glutathione S-transferases (GSTs) proteins and vascular endothelial growth factor (VEGF) is complex and multifaceted, according to recent evidence, and these proteins actively participate in many tumorigenic processes such as cell proliferation, cell survival and drug resistance. The VEGF and GSTs are now widely acknowledged as an important target for antitumor therapy. Thus, in this present study, ivermectin displayed promising inhibition of bladder cancer cells via targeting VEGF and GSTs signaling. Moreover, molecular docking and molecular dynamics (MD) simulation analysis revealed that ivermectin efficiently targeted the binding pockets of VEGF receptor proteins and possessed stable dynamics behavior at binding sites. Therefore, we proposed here that these compounds must be tested experimentally against VEGF and GST signaling in order to control SABC. Our study lies within the idea of discovering repurposing drugs as inhibitors against the different types of human cancers by targeting essential pathways in order to accelerate the drug development cycle.

Endochin-like quinolones (ELQs) and bumped kinase inhibitors (BKIs): Synergistic and additive effects of combined treatments against Neospora caninum infection in vitro and in vivo

The apicomplexan parasite Neospora caninum is an important causative agent of congenital neosporosis, resulting in abortion, birth of weak offspring and neuromuscular disorders in cattle, sheep, and many other species. Among several compound classes that are currently being developed, two have been reported to limit the effects of congenital neosporosis: (i) bumped kinase inhibitors (BKIs) target calcium dependent protein kinase 1 (CDPK1), an enzyme that is encoded by an apicoplast-derived gene and found only in apicomplexans and plants. CDPK1 is essential for host cell invasion and egress; (ii) endochin-like quinolones (ELQs) are inhibitors of the cytochrome bc₁ complex of the mitochondrial electron transport chain and thus inhibit oxidative phosphorylation. We here report on the in vitro and in vivo activities of BKI-1748, and of ELQ-316 and its respective prodrugs ELQ-334 and ELQ-422, applied either as single-compounds or ELQ-BKI-combinations. In vitro, BKI-1748 and ELQ-316, as well as BKI-1748 and ELQ-334, acted synergistically, while this was not observed for the BKI-1748/ELQ-422 combination treatment. In a N. caninum-infected pregnant BALB/c mouse model, the synergistic effects observed in vitro were not entirely reproduced, but 100% postnatal survival and 100% inhibition of vertical transmission was noted in the group treated with the BKI-1748/ELQ-334 combination. In addition, the combined drug applications resulted in lower neonatal mortality compared to treatments with single drugs.

Piperine: Chemical, biological and nanotechnological applications

Piperine (PIP) is an alkaloid present in several species of piper, mainly Piper nigrum Linn. and P. longum, among other species. The present article provides a comprehensive review of PIP research in the last years concerning its chemical properties, synthesis, absorption, metabolism, bioavailability and toxicity. The reviewed PIP literature has shown many pharmacological properties, such as antidiabetic, antidiarrheal, antioxidant, antibacterial, and anti-parasitic activity of PIP. However, its low solubility and absorption make its application challenging. This review also includes advances in the development of nanosystems containing PIP, including liposomes, micelles, metal nanoparticles, nanofibers, polymeric nanoparticles, and solid-lipid nanoparticles. Finally, we discuss different in vitro and in vivo studies to evaluate the biological activity of this drug, as well as some methods for the synthesis of nanosystems and their physical characteristics.

Drugs that inhibit TMEM16 proteins block SARS-CoV-2 spike-induced syncytia

COVID-19 is a disease with unique characteristics that include lung thrombosis1, frequent diarrhoea2, abnormal activation of the inflammatory response3 and rapid deterioration of lung function consistent with alveolar oedema4. The pathological substrate for these findings remains unknown. Here we show that the lungs of patients with COVID-19 contain infected pneumocytes with abnormal morphology and frequent multinucleation. The generation of these syncytia results from activation of the SARS-CoV-2 spike protein at the cell plasma membrane level. On the basis of these observations, we performed two high-content microscopy-based screenings with more than 3,000 approved drugs to search for inhibitors of spike-driven syncytia. We converged on the identification of 83 drugs that inhibited spike-mediated cell fusion, several of which belonged to defined pharmacological classes. We focused our attention on effective drugs that also protected against virus replication and associated cytopathicity. One of the most effective molecules was the antihelminthic drug niclosamide, which markedly blunted calcium oscillations and membrane conductance in spike-expressing cells by suppressing the activity of TMEM16F (also known as anoctamin 6), a calcium-activated ion channel and scramblase that is responsible for exposure of phosphatidylserine on the cell surface. These findings suggest a potential mechanism for COVID-19 disease pathogenesis and support the repurposing of niclosamide for therapy.

Halogenated tryptophan derivatives disrupt essential transamination mechanisms in bloodstream form Trypanosoma brucei

Amino acid metabolism within Trypanosoma brucei, the causative agent of human African trypanosomiasis, is critical for parasite survival and virulence. Of these metabolic processes, the transamination of aromatic amino acids is one of the most important. In this study, a series of halogenated tryptophan analogues were investigated for their anti-parasitic potency. Several of these analogues showed significant trypanocidal activity. Metabolomics analysis of compound-treated parasites revealed key differences occurring within aromatic amino acid metabolism, particularly within the widely reported and essential transamination processes of this parasite.

Nanotechnological strategies for systemic microbial infections treatment: A review

Systemic infections is one of the major causes of mortality worldwide, and a shortage of drug approaches applied for the rapid and necessary treatment contribute to increase the levels of death in affected patients. Several drug delivery systems based in nanotechnology such as metallic nanoparticles, liposomes, nanoemulsion, microemulsion, polymeric nanoparticles, solid lipid nanoparticles, dendrimers, hydrogels and liquid crystals can contribute in the biological performance of active substances for the treatment of microbial diseases triggered by fungi, bacteria, virus and parasites. In the presentation of these statements, this review article present and demonstrate the effectiveness of these drug delivery systems for the treatment of systemic diseases caused by several microorganisms, through a review of studies on scientific literature worldwide that contributes to better information for the most diverse professionals from the areas of health sciences. The studies demonstrated that the drug delivery systems described can contribute to the therapeutic scenario of these diseases, being classified as safe, active platforms and with therapeutic versatility.

CaCO3 crystals as versatile carriers for controlled delivery of antimicrobials

CaCO₃ crystals have been known for a long time as naturally derived and simply fabricated nano(micro)-sized materials able to effectively host and release various molecules. This review summarises the use of CaCO₃ crystals as versatile carriers to host, protect and release antimicrobials, offering a strong tool to tackle antimicrobial resistance, a serious global health problem. The main methods for the synthesis of CaCO₃ crystals with different properties, as well as the approaches for the loading and release of antimicrobials are presented. Finally, prospects to utilize the crystals in order to improve the therapeutic outcome and combat antimicrobial resistance are highlighted. Ultimately, this review intends to provide an in-depth overview of the application of CaCO₃ crystals for the smart and controlled delivery of antimicrobial agents and aims at identifying the advantages and drawbacks as well as guiding future works, research directions and industrial applications.

Repurposing the Antiamoebic Drug Diiodohydroxyquinoline for Treatment of Clostridioides difficile Infections

Clostridioides difficile, the leading cause of nosocomial infections, is an urgent health threat worldwide. The increased incidence and severity of disease, the high recurrence rates, and the dearth of effective anticlostridial drugs have created an urgent need for new therapeutic agents. In an effort to discover new drugs for the treatment of Clostridioides difficile infections (CDIs), we investigated a panel of FDA-approved antiparasitic drugs against C. difficile and identified diiodohydroxyquinoline (DIHQ), an FDA-approved oral antiamoebic drug. DIHQ exhibited potent activity against 39 C. difficile isolates, inhibiting growth of 50% and 90% of these isolates at concentrations of 0.5 μg/ml and 2 μg/ml, respectively. In a time-kill assay, DIHQ was superior to vancomycin and metronidazole, reducing a high bacterial inoculum by 3 log₁₀ within 6 h. Furthermore, DIHQ reacted synergistically with vancomycin and metronidazole against C. difficile in vitro. Moreover, at subinhibitory concentrations, DIHQ was superior to vancomycin and metronidazole in inhibiting two key virulence factors of C. difficile, toxin production and spore formation. Additionally, DIHQ did not inhibit the growth of key species that compose the host intestinal microbiota, such as Bacteroides, Bifidobacterium, and Lactobacillus spp. Collectively, our results indicate that DIHQ is a promising anticlostridial drug that warrants further investigation as a new therapeutic for CDIs.

Scorpion Venom: Detriments and Benefits

Scorpion venom may cause severe medical complications and untimely death if injected into the human body. Neurotoxins are the main components of scorpion venom that are known to be responsible for the pathological manifestations of envenoming. Besides neurotoxins, a wide range of other bioactive molecules can be found in scorpion venoms. Advances in separation, characterization, and biotechnological approaches have enabled not only the development of more effective treatments against scorpion envenomings, but have also led to the discovery of several scorpion venom peptides with interesting therapeutic properties. Thus, scorpion venom may not only be a medical threat to human health, but could prove to be a valuable source of bioactive molecules that may serve as leads for the development of new therapies against current and emerging diseases. This review presents both the detrimental and beneficial properties of scorpion venom toxins and discusses the newest advances within the development of novel therapies against scorpion envenoming and the therapeutic perspectives for scorpion toxins in drug discovery.

In vitro Evaluation of Mannosylated Paromomycin-Loaded Solid Lipid Nanoparticles on Acute Toxoplasmosis

Toxoplasma gondii is a zoonotic intracellular protozoan with worldwide distribution. Acute and severe toxoplasmosis are commonly reported in patients who suffer from acquired/congenital immune deficiency. This study aimed to synthesize mannosylated paromomycin-loaded solid lipid nanoparticles (PM-SLN-M) and to evaluate them on acute toxoplasmosis. SLN was synthesized and then loaded by 7 mg/mL paromomycin sodium. Mannose coating was performed, and after washing, the size, zeta potential, and loading percentage were calculated. To evaluate the cell toxicity, an MTT assay was performed on Vero cells by different concentrations (log 10^-1) of SLN, PM-SLN-M, and PM-SLN. In addition, the anti-Toxoplasma effects were also evaluated using trypan-blue staining and scanning electron microscopy (SEM). An MTT assay was also employed to evaluate the effects of PM and PM-SLN-M on intracellular Toxoplasma. A 6-month stability test of PM-SLN and PM-SLN-M represented that the characteristics all remained constant. The cell viability assay demonstrated that PM-SLN-M had lower cell toxicity (<20%) compared to PM-SLN (<30%) and PM (<40%). Statistical analysis showed that PM-SLN-M significantly killed ~97.555 ± 0.629 (95% CI: 91.901 to 103.209; P < 0.05) of T. gondii tachyzoites. More than 50% of Toxoplasma-infected Vero cells remained viable in concentrations more than 0.07 μg/mL and 7 μg/mL of PM and PM-SLN-M, respectively. SEM analysis showed that T. gondii tachyzoites were changed in both size and morphology facing with PM-SLN-M. Our findings indicated that synthesized PM-SLN-M had anti-Toxoplasma activity without significant host cell toxicity at the highest concentration. Our study demonstrated that PM was able to kill intracellular Toxoplasma in lower concentration in comparison to PM-SLN-M, although PM-SLN-M showed lower cytotoxic effects on Vero cells.

Case report: Albendazole associated psychosis

Introduction

The association of psychosis with albendazole monotherapy has not been established in current literature.

Case Report

We present the first reported case of acute psychosis associated with albendazole. Upon cessation of the agent and the introduction of aripiprazole, the patient's psychosis remitted, and the patient did not present for acute treatment in the months to follow.

Discussion/Conclusion

The temporal relationship and laboratory data support albendazole's role in leading to the aforementioned toxicity. Such reactions, although rare, can drastically impact patient care and may warrant increased provider consideration when choosing to prescribe albendazole.

Space Occupying Lesion in the Liver Caused by Hepatic Visceral Larva Migrans: A Case Report

Visceral larva migrans (VLM) is one of the clinical syndromes of human toxocariasis. We report a case of hepatic VLM presenting preprandial malaise and epigastric discomfort in a 58-year-old woman drinking raw roe deer blood. The imaging studies of the abdomen showed a 74-mm hepatic mass featuring hepatic VLM. Anti-Toxocara canis immunoglobulin G (IgG) was observed in enzyme-linked immunosorbent assay (ELISA) and western blot. Despite anthelmintic treatment, the patient complained of newly developed cough and skin rash with severe eosinophilia. Hepatic lesion increased in size. The patient underwent an open left lobectomy of the liver. After the surgery, the patient was free of symptoms such as preprandial malaise, epigastric discomfort, cough, and skin rash. Laboratory test showed a normal eosinophilic count at postoperative 1 month, 6 months, 1 year, and 4 years. The initial optical density value of 2.55 of anti-T. canis IgG in ELISA was found to be negative (0.684) at postoperative 21 months. Our case report highlights that a high degree of clinical suspicion for hepatic VLM should be considered in a patient with a history of ingestion of raw food in the past, presenting severe eosinophilia and a variety of symptoms which reflect high worm burdens. Symptom remission, eosinophilia remission, and complete radiological resolution of lesions can be complete with surgery.

Therapeutic Interventions for Countering Leishmaniasis and Chagas's Disease: From Traditional Sources to Nanotechnological Systems

The incidence of neglected diseases in tropical countries, such as Leishmaniasis and Chagas's disease, is attributed to a set of biological and ecological factors associated with the socioeconomic context of developing countries and with a significant burden to health care systems. Both Leishmaniasis and Chagas's disease are caused by different protozoa and develop diverse symptoms, which depend on the specific species infecting man. Currently available drugs to treat these disorders have limited therapeutic outcomes, frequently due to microorganisms' drug resistance. In recent years, significant efforts have been made towards the development of innovative drug delivery systems aiming to improve bioavailability and pharmacokinetic profiles of classical drug therapy. This paper discusses the key facts of Leishmaniasis and Chagas's disease, the currently available pharmacological therapies and the new drug delivery systems for conventional drugs.

Decoy Receptor Interactions as Novel Drug Targets against EKC-Causing Human Adenovirus

Epidemic keratoconjunctivitis (EKC) is a severe ocular disease and can lead to visual impairment. Human adenovirus type-37 (HAdV-D37) is one of the major causative agents of EKC and uses sialic acid (SA)-containing glycans as cellular receptors. Currently, there are no approved antivirals available for the treatment of EKC. Recently, we have reported that sulfated glycosaminoglycans (GAGs) bind to HAdV-D37 via the fiber knob (FK) domain of the viral fiber protein and function as decoy receptors. Based on this finding, we speculated that GAG-mimetics may act as artificial decoy receptors and inhibit HAdV-D37 infection. Repurposing of approved drugs to identify new antivirals has drawn great attention in recent years. Here, we report the antiviral effect of suramin, a WHO-approved drug and a widely known GAG-mimetic, against HAdV-D37. Commercially available suramin analogs also show antiviral effects against HAdV-D37. We demonstrate that suramin exerts its antiviral activity by inhibiting the attachment of HAdV-D37 to cells. We also reveal that the antiviral effect of suramin is HAdV species-specific. Collectively, in this proof of concept study, we demonstrate for the first time that virus binding to a decoy receptor constitutes a novel and an unexplored target for antiviral drug development.

Antiamoebic drugs for treating amoebic colitis

BACKGROUND

Infection with the protozoan Entamoeba histolytica is common in low- and middle-income countries, and up to 100,000 people with severe disease die every year. Adequate therapy for amoebic colitis is necessary to reduce illness, prevent development of complicated disease and extraintestinal spread, and decrease transmission.

OBJECTIVES

To evaluate antiamoebic drugs for treating amoebic colitis.

SEARCH METHODS

We searched the available literature up to 22 March 2018. We searched the Cochrane Infectious Diseases Group Specialised Register, CENTRAL, MEDLINE, Embase, LILACS, mRCT, and conference proceedings. We contacted individual researchers, organizations, and pharmaceutical companies, and we checked reference lists.

SELECTION CRITERIA

Randomized controlled trials of antiamoebic drugs given alone or in combination, compared with placebo or another antiamoebic drug, for treating adults and children with a diagnosis of amoebic colitis.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed the eligibility and methodological quality of trials and extracted and analysed the data. We calculated clinical and parasitological failure rates and rates of relapse and adverse events as risk ratios (RRs) with 95% confidence intervals (CIs), using a random-effects model. We determined statistical heterogeneity and explored possible sources of heterogeneity using subgroup analyses. We carried out sensitivity analysis by using trial quality to assess the robustness of reported results.

MAIN RESULTS

In total, 41 trials (4999 participants) met the inclusion criteria of this review. In this update, we added four trials to the 37 trials included in the first published review version. Thirty trials were published over 20 years ago. Only one trial used adequate methods of randomization and allocation concealment, was blinded, and analysed all randomized participants. Only one trial used an E histolytica stool antigen test, and two trials used amoebic culture.Tinidazole may be more effective than metronidazole for reducing clinical failure (RR 0.28, 95% CI 0.15 to 0.51; 477 participants, eight trials; low-certainty evidence) and is probably associated with fewer adverse events (RR 0.65, 95% CI 0.46 to 0.92; 477 participants, 8 trials; moderate-certainty evidence). Compared with metronidazole, combination therapy may result in fewer parasitological failures (RR 0.36, 95% CI 0.15 to 0.86; 720 participants, 3 trials; low-certainty evidence), but we are uncertain which combination is more effective than another. Evidence is insufficient to allow conclusions regarding the efficacy of other antiamoebic drugs.

AUTHORS' CONCLUSIONS

Compared with metronidazole, tinidazole may be more effective in reducing clinical failure and may be associated with fewer adverse events. Combination drug therapy may be more effective for reducing parasitological failure compared with metronidazole alone. However, these results are based mostly on small trials conducted over 20 years ago with a variety of poorly defined outcomes. Tests that detect E histolytica more accurately are needed, particularly in countries where concomitant infection with other bacteria and parasites is common.

Effect of probiotic Saccharomyces boulardii in experimental giardiasis

The aim of the study was to assess the efficacy of Saccharomyces boulardii in experimental treatment of giardiasis and its impact on intestinal integrity and some functions of gerbils infected with Giardia lamblia. 28 gerbils (Meriones unguiculatus), aged 4-6 weeks, were divided into four groups: untreated and uninfected control (CT); infected with G. lamblia (IGL); treated with S. boulardii (SB); and infected with G. lamblia and treated with S. boulardii (ITSB). The SB and ITSB groups received S. boulardii 15 days prior to being infected with G. lamblia. The treatment continued until completion of the experiment (22nd day). The IGL and ITSB groups were gavage-inoculated with G. lamblia ensuring one-week infection. 4 h before euthanasia, all animals were gavaged with a solution containing diethylenetriamine-pentaacetic acid (DTPA) marked with technetium-99mTc DTPA to determine intestinal permeability. The small intestine was removed for histopathological, morphometric analysis and count of trophozoites adhered to the mucosa. The selected probiotic caused an approximate reduction of 70% of parasite load, which was determined by attached trophozoites (P<0.01) and immune-marked trophozoites (P<0.05). Treatment with S. boulardii (SB and ITSB groups) also increased the height of the intestinal villi and crypt depth compared to the CT and IGL groups (P<0.05). The area of mucus production and the number of goblet cells of the SB and ITSB groups were higher compared to the CT and IGL groups (P<0.01). The animals treated with S. boulardii also exhibited a significant increase of intraepithelial lymphocytes counts (P<0.01). There was no difference in the intestinal permeability between the groups studied. The efficacy of S. boulardii in reducing damages caused by Giardia was demonstrated, with an approximate reduction of 70% of the parasite load, suggesting its use as a coadjuvant in giardiasis treatment.

Repurposing the anthelmintic drug niclosamide to combat Helicobacter pylori

There is an urgent need to discover novel antimicrobial therapies. Drug repurposing can reduce the time and cost risk associated with drug development. We report the inhibitory effects of anthelmintic drugs (niclosamide, oxyclozanide, closantel, rafoxanide) against Helicobacter pylori strain 60190 and pursued further characterization of niclosamide against H. pylori. The MIC of niclosamide against H. pylori was 0.25 μg/mL. Niclosamide was stable in acidic pH and demonstrated partial synergy with metronidazole and proton pump inhibitors, such as omeprazole and pantoprazole. Niclosamide administration at 1 × MIC concentration, eliminated 3-log₁₀ CFU of H. pylori adhesion/invasion to AGS cells. Interestingly, no resistance developed even after exposure of H. pylori bacteria to niclosamide for 30 days. The cytotoxic assay demonstrated that niclosamide is not hemolytic and has an IC₅₀ of 4 μg/mL in hepatic and gastric cell lines. Niclosamide administration decreased transmembrane pH as determined by DiSC₃(5) assay indicating that the mechanism of action of the anti-H. pylori activity of niclosamide was the disruption of H. pylori proton motive force. Niclosamide was effective in the Galleria mellonella-H. pylori infection model (p = 0.0001) and it can be develop further to combat H. pylori infection. However, results need to be confirmed with other H. pylori and clinical strains.

A benzimidazole derivative (RCB15) in vitro induces the alternative energetic metabolism and glycolysis in Taenia crassiceps cysticerci

The emergence of resistance to albendazole has encouraged the search for effective alternatives for cysticercosis and other parasitosis treatment. RCB15 is a benzimidazole derivative that may be used against such diseases. The aim of this study was to determine the in vitro effect of RCB15 on the alternative energetic pathways of Taenia crassiceps cysticerci. The cysticerci were in vitro exposed to albendazole sulphoxide (ABZSO) or RCB15 at different concentrations during 24h. The cysticerci extract and the culture medium were analyzed through spectrophotometry and high performance liquid chromatography as to detect glucose, urea, creatinine and organic acids of the energetic metabolism. The drugs did not influence the protein catabolism. Fatty acids oxidation was enhanced through significantly higher acetate concentrations in the groups treated with RCB15 and ABZSO. Beta-hydroxybutyrate concentrations were decreased which indicates the use of fatty acids towards acetyl-CoA synthesis. There was a decrease in glucose uptake and pyruvate concentrations. The absence of lactate indicates the use of pyruvate in gluconeogenesis. Therefore it is possible to conclude that RCB15 enhanced the alternative energetic pathways of cysticerci in vitro exposed to different concentration, with emphasis on the fatty acids catabolism.

Rapid resolution of toxoplasma chorioretinitis treatment using quadruple therapy

Purpose

To compare the effectiveness of quadruple-drug therapy consisting of cotrimoxazole (trimethopin and sulfamethoxazole), clindamycin antibiotics, and oral corticosteroid versus triple therapy consisting of pyrimetamine, sulphadiazine, and oral corticosteroid in the resolution of toxoplasmic chorioretinitis.

Methods

This was a double-blind randomized controlled trial with repeated measures using parallel design to compare the effectiveness of quadruple-drug therapy and triple-drug therapy in patients with toxoplasmic chorioretinitis. The measurement of lesion was done using automated computer software, calculating the average of lesion size from three fundus photographs taken from the baseline and at each follow-up visit. The analytical statistics were obtained using Mann-Whitney test, comparing percentage of lesion remission test in each examination.

Results

The percentage of lesion remission in quadruple-drug therapy was higher than in triple-drug therapy from the first visit until the first follow-up visit, with a p-value of 0.001. In addition, the mean percentage of lesion remission from first visit to last visit was 57.5% and the median was 70.9% in the quadruple therapy group, while in the triple-drug therapy group the mean was 52.5% and the median was 54.0% (p=0.720).

Conclusion

We conclude that the quadruple-drug therapy has a more rapid resolution effect on chorioretinitis lesion compared to triple therapy.

The Global State of Helminth Control and Elimination in Children

Helminth infections, including soil-transmitted helminths and schistosomiasis, remain one of the most common infections in the world with over 1 billion people infected. These infections cause significant morbidity, particularly in young children, that may last a lifetime, including growth and cognitive stunting. There is an urgent need for the control and elimination of helminth infections from areas of poverty to reduce morbidity in children. Mass drug administration programs were adopted by the World Health Assembly in 2001 and have evolved to provide coverage with multiple anthelmintic medications in a single rapid impact package and more extensive coverage within a community.

An Update Review on the Anthelmintic Activity of Bitter Gourd, Momordica charantia

Momordica charantia (Family: Cucurbitales), as known as bitter melon or gourd, is a daily consumption as food and traditional medicinal plant in Southeast Asia and Indo-China. It has been shown to possess anticancer, antidepressant, antidiabetic, anti-inflammatory, antimicrobial, antiobesity, antioxidant, and antiulcer properties. Its common phytochemical components include alkaloids, charantin, flavonoids, glycosides, phenolics, tannins, and terpenoids. This plant is rich in various saponins including momordicin, momordin, momordicoside, karavilagenin, karaviloside, and kuguacin, all of which have been reported to contribute to its remedial properties including antibacterial, antifungal, antiviral, and antiparasitic infections. Based on established literature on the anthelmintic activity of M. charantia and possible mode of action, this review article has attempted to compile M. charantia could be further explored for the development of potential anthelmintic drug.

[Clinical approach to imported eosinophilia]

Eosinophilia is a common finding in international travelers and immigrants, being an helmintic infection its main etiology. The positive predictive value of eosinophilia for an helmintosis is low in travellers. Eosinophilia may be an incidental finding, or symptomatic, and it represents a clinical challenge due to the low sensitivity and specificity of direct and indirect parasitological diagnostic tests, respectively. It requires a structured approach based on geographical areas, environmental exposures and behavioral risks, and associated symptoms. The initial assessment should include a comprehensive and tailored anamnesis and physical examination, basic laboratory tests, a complete parasitological examination of stool samples and a Strongyloides stercoralis serology, supplemented with other explorations guided by epidemiological and clinical suspicion. Empiric treatment with albendazole and/or ivermectin (plus praziquantel if risk of schistosomiasis) is an option for unidentified persistent eosinophilia after study, and in persons in whom a proper assessment or follow-up can not be assured. In patients at risk for estrongiloidosis who are candidates for immunosuppressive therapies, it is indicated a prior screening and treatment to prevent a future hyperinfestation syndrome.

Parasitic Infections in Hematopoietic Stem Cell Transplantation

Parasitic infections are rarely documented in hematopoietic stem cell transplant recipients. However they may be responsible for fatal complications that are only diagnosed at autopsy. Increased awareness of the possibility of parasitic diseases both in autologous and allogeneic stem cell transplant patients is relevant not only for implementing preventive measures but also for performing an early diagnosis and starting appropriate therapy for these unrecognized but fatal infectious complications in hematopoietic transplant recipients. In this review, we will focus on parasitic diseases occurring in this population especially those with major clinical relevance including toxoplasmosis, American trypanosomiasis, leishmaniasis, malaria, and strongyloidiasis, among others, highlighting the diagnosis and management in hematopoietic transplant recipients.

Development of new highly potent imidazo[1,2-b]pyridazines targeting Toxoplasma gondii calcium-dependent protein kinase 1

Using a structure-based design approach, we have developed a new series of imidazo[1,2-b]pyridazines, targeting the calcium-dependent protein kinase-1 (CDPK1) from Toxoplasma gondii. Twenty derivatives were thus synthesized. Structure-activity relationships and docking studies confirmed the binding mode of these inhibitors within the ATP binding pocket of TgCDPK1. Two lead compounds (16a and 16f) were then identified, which were able to block TgCDPK1 enzymatic activity at low nanomolar concentrations, with a good selectivity profile against a panel of mammalian kinases. The potential of these inhibitors was confirmed in vitro on T. gondii growth, with EC50 values of 100 nM and 70 nM, respectively. These best candidates also displayed low toxicity to mammalian cells and were selected for further in vivo investigations on murine model of acute toxoplasmosis.

Ascaris lumbricoides β carbonic anhydrase: a potential target enzyme for treatment of ascariasis

BACKGROUND

A parasitic roundworm, Ascaris lumbricoides, is the causative agent of ascariasis, with approximately 760 million cases around the world. Helminthic infections occur with a high prevalence mostly in tropical and developing xcountries. Therefore, design of affordable broad-spectrum anti-helminthic agents against a variety of pathogens, including not only A. lumbricoides but also hookworms and whipworms, is desirable. Beta carbonic anhydrases (β-CAs) are considered promising targets of novel anthelminthics because these enzymes are present in various parasites, while completely absent in vertebrates.

METHODS

In this study, we identified an A. lumbricoides β-CA (AIBCA) protein from protein sequence data using bioinformatics tools. We used computational biology resources and methods (including InterPro, CATH/Gene3D, KEGG, and METACYC) to analyze AlBCA and define potential roles of this enzyme in biological pathways. The AlBCA gene was cloned into pFastBac1, and recombinant AIBCA was produced in sf-9 insect cells. Kinetics of AlBCA were analyzed by a stopped-flow method.

RESULTS

Multiple sequence alignment revealed that AIBCA contains the two sequence motifs, CXDXR and HXXC, typical for β-CAs. Recombinant AIBCA showed significant CA catalytic activity with kcat of 6.0 × 10(5) s(-1) and kcat/KM of 4.3 × 10(7) M(-1) s(-1). The classical CA inhibitor, acetazolamide, showed an inhibition constant of 84.1 nM. Computational modeling suggests that the molecular architecture of AIBCA is highly similar to several other known β-CA structures. Functional predictions suggest that AIBCA might play a role in bicarbonate-mediated metabolic pathways, such as gluconeogenesis and removal of metabolically produced cyanate.

CONCLUSIONS

These results open new avenues to further investigate the precise functions of β-CAs in parasites and suggest that novel β-CA specific inhibitors should be developed and tested against helminthic diseases.

Worm Infections in Children

• On the basis of research evidence, worm infections are important global child health conditions causing chronic disability that lasts from childhood into adulthood (Table 1). (2)(3) Evidence Quality: B • On the basis of research evidence, the major worm infections found in developing countries include ascariasis, trichuriasis, hookworm infection, and schistosomiasis; toxocariasis, enterobiasis, and cysticercosis are also found in poor regions of North America and Europe. (4)(9)(13) Evidence Quality: B • On the basis of expert consensus, children and adolescents are often vulnerable to acquiring large numbers of worms, ie, high-intensity infections (Fig 1)(21)(22)(23) Evidence Quality: D • On the basis of expert consensus and research evidence, moderate and heavy worm burdens cause increased morbidity because of growth and intellectual stunting in children and adolescents. Many of these effects may result from helminth-induced malnutrition. (21)(22)(23) Evidence Quality: C • On the basis of expert consensus and research evidence, worm infections are also commonly associated with eosinophilia. (48) (49) Evidence Quality: B • On the basis of research evidence as well as consensus, helminthes can cause inflammation in the lung (asthma), gastrointestinal tract (enteritis and colitis), liver (hepatitis and fibrosis), and urogenital tract. (7)(21)(22)(23)(27)(28)(40)(41)(43) Evidence Quality: B • On the basis of research evidence, microscopy techniques for diagnosis of worm infections in children often exhibit suboptimal sensitivities and specificities, necessitating new or improved diagnostic modalities such as polymerase chain reaction. (54)(55) Evidence Quality: A • On the basis of research evidence and expert consensus, mass drug administration (“preventive chemotherapy”) has becomea standard practice for ministries of health in low- and middle-income countries to control intestinal helminth infections and schistosomiasis. (67)(68) Evidence Quality: B.

A small-molecule cell-based screen led to the identification of biphenylimidazoazines with highly potent and broad-spectrum anti-apicomplexan activity

An in vitro screening of the anti-apicomplexan activity of 51 compounds, stemming from our chemical library and from chemical synthesis, was performed. As a study model, we used Toxoplasma gondii (T. gondii), expressing β-galactosidase for the colorimetric assessment of drug activity on parasites cultivated in vitro. This approach allowed the validation of a new series of molecules with a biphenylimidazoazine scaffold as inhibitors of T. gondii growth in vitro. Hence, 8 molecules significantly inhibited intracellular replication of T. gondii in vitro, with EC50 < 1 μM, while being non-toxic for human fibroblasts at these concentrations. Most attractive candidates were then selected for further biological investigations on other apicomplexan parasites (Neospora caninum, Besnoitia besnoiti, Eimeria tenella and Plasmodium falciparum). Finally, two compounds were able to inhibit growth of four different apicomplexans with EC50 in the submicromolar to nanomolar range, for each parasite. These data, including the broad anti-parasite spectrum of these inhibitors, define a new generation of potential anti-parasite compounds of wide interest, including for veterinary application. Studies realized on E. tenella suggest that these molecules act during the intracellular development steps of the parasite. Further experiments should be done to identify the molecular target(s) of these compounds.

The approved pediatric drug suramin identified as a clinical candidate for the treatment of EV71 infection-suramin inhibits EV71 infection in vitro and in vivo

Enterovirus 71 (EV71) causes severe central nervous system infections, leading to cardiopulmonary complications and death in young children. There is an urgent unmet medical need for new pharmaceutical agents to control EV71 infections. Using a multidisciplinary approach, we found that the approved pediatric antiparasitic drug suramin blocked EV71 infectivity by a novel mechanism of action that involves binding of the naphtalentrisulonic acid group of suramin to the viral capsid. Moreover, we demonstrate that when suramin is used in vivo at doses equivalent to or lower than the highest dose already used in humans, it significantly decreased mortality in mice challenged with a lethal dose of EV71 and peak viral load in adult rhesus monkeys. Thus, suramin inhibits EV71 infection by neutralizing virus particles prior to cell attachment. Consequently, these findings identify suramin as a clinical candidate for further development as a therapeutic or prophylactic treatment for severe EV71 infection.