Nitazoxanide Research Articles

Nitazoxanide induced myocardial injury in zebrafish embryos by activating oxidative stress response.

Nitazoxanide (NTZ) is a broad‐spectrum antiparasitic and antiviral drug (thiazole). However, although NTZ has been extensively used, there are no reports concerning its toxicology in vertebrates. This study used the zebrafish as a vertebrate model to evaluate the safety of NTZ and to analyse the related molecular mechanisms. The experimental results showed that zebrafish embryos exposed to NTZ had cardiac malformation and dysfunction. NTZ also significantly inhibited proliferation and promoted apoptosis in cardiomyocytes. Transcriptomic analysis used compared gene expression levels between zebrafish embryos in the NTZ treatment and the control groups identified 200 upregulated genes and 232 downregulated genes. Analysis by Kyoto encyclopaedia of genes and genomes (KEGG) and gene ontology (GO) showed that signal pathways on cardiomyocyte development were inhibited while the oxidative stress pathways were activated. Further experiments showed that NTZ increased the content of reactive oxygen species (ROS) in the hearts of zebrafish. Antioxidant gadofullerene nanoparticles (GFNPs) significantly alleviated the developmental toxicity to the heart, indicating that NTZ activated the oxidative stress response to cause embryonic cardiomyocyte injury in zebrafish. This study provides evidence that NTZ causes developmental abnormalities in the cardiovascular system of zebrafish.

HBx-induced degradation of Smc5/6 complex impairs homologous recombination-mediated repair of damaged DNA

HBV causes hepatocellular carcinoma (HCC). While it was recently shown that the ability of HBV X protein (HBx) to impair the Smc5/6 (structural maintenance of chromosome 5/6) complex is important for viral transcription, HBx is also a potent driver of HCC. However, the mechanism by which HBx expression induces hepatocarcinogenesis is unclear. Degradation of the Smc5/6 complex and accumulation of DNA damage were observed in both invivo and invitro HBV infection models. Rescue experiments were performed using nitazoxanide (NTZ), which inhibits degradation of the Smc5/6 complex by HBx. HBx-triggered degradation of the Smc5/6 complex causes impaired homologous recombination (HR) repair of DNA double-strand breaks (DSBs), leading to cellular transformation. We found that DNA damage accumulated in the liver tissue of HBV-infected humanized chimeric mice, HBx-transgenic mice, and human tissues. HBx suppressed the HR repair of DSBs, including that induced by the CRISPR-Cas9 system, in an Smc5/6-dependent manner, which was rescued by restoring the Smc5/6 complex. NTZ restored HR repair in, and colony formation by, HBx-expressing cells. Degradation of the Smc5/6 complex by HBx increases viral transcription and promotes cellular transformation by impairing HR repair of DSBs. The hepatitis B virus expresses a regulatory protein called HBV X protein (or HBx). This protein degrades the Smc5/6 complex in human hepatocytes, which is essential for viral replication. We found that this process also plays a key role in the accumulation of DNA damage, which contributes to HBx-mediated tumorigenesis.

Evaluation of the role of combined prebiotic and probiotic supplements as prophylactic and therapeutic agents against experimental giardiasis

Background: Giardiasis is considered as one of the most prevalent gastrointestinal parasitic infectionsworldwide. Most of the used anti-Giardia drugs may cause side effects and are often associated withclinical failure and drug resistance. Prebiotic and probiotic therapy has been posited as potential naturaltherapeutic agent for many parasitic diseases.Objective: To evaluate the effect of combined prebiotic and probiotic therapy as a natural supplement andafter addition to nitazoxanide (NTZ) in treatment of giardiasis in murine model.Material and Methods: Ninety-six laboratory bred Swiss albino male mice were used. Mice were dividedinto three main groups that included 16 subgroups (6 mice each). Control group (A1-7) included controlnegative (non-infected non-treated), control positive (infected non-treated), and another five controlsubgroups (SGs) that received natural prebiotic and probiotic supplements and NTZ. Prophylactic group (B)included three SGs in which infected mice received prebiotic and probiotic separately and in combinationfor one week before infection and continued till the end of experiment. Infected treated group (C1-6)composed of six infected SGs that received treatment by prebiotic and probiotic separately, and combinedprebiotic/probiotic, NTZ alone (full dose), and after addition of combined supplement to NTZ (half orfull dose). Evaluation was achieved using parasitological, histopathological, immunohistochemical, andimmunological parameters.Results: There was significant reduction of Giardia cyst shedding in all prophylactic and infected treatedSGs. The highest mean cyst reduction was observed in group C after addition of combined supplementto NTZ post infection (PI) and in group B receiving prophylactic combined supplement. Remarkableimprovement of histopathological findings was observed especially in group C after receiving combinedsupplement in addition to NTZ, followed by other prophylactic and infected treated SGs. The resultsof immunohistochemical caspase 3 expression revealed that combined supplement was effective inpreventing apoptotic cell death of intestinal cells that is induced by giardiasis especially after addition ofcombined supplement to NTZ in group C. Immunological assessment of interleukin-6 (IL-6) level showedsignificant increase in all treated SGs with boosted elevation in combined supplement after addition toNTZ in group C.Conclusion: Combined prebiotic and probiotic products can be considered as good prophylactic andtherapeutic agents when added to NTZ against giardiasis.

The Modulation of Cholesterol Metabolism Is Involved in the Antiviral Effect of Nitazoxanide.

We previously investigated the role of Nitazoxanide (NTZ), a thiazolide endowed with antiviral and antiparasitic activity, in HIV-1 infection. NTZ treatment in primary isolated PBMCs was able to reduce HIV-1 infection in vitro by inducing the expression of a number of type-I interferon-stimulated genes. Among them, NTZ was able to induce cholesterol-25-hydroxylase (CH25H), which is involved in cholesterol metabolism. In the present study, we wanted to deepen our knowledge about the antiviral mechanism of action of NTZ. Indeed, by inducing CH25H, which catalyzes the formation of 25-hydroxycholesterol from cholesterol, NTZ treatment repressed cholesterol biosynthetic pathways and promoted cholesterol mobilization and efflux from the cell. Such effects were even more pronounced upon stimulation with FLU antigens in combination. It is already well known how lipid metabolism and virus replication are tightly interconnected; thus, it is not surprising that the antiviral immune response employs genes related to cholesterol metabolism. Indeed, NTZ was able to modulate cholesterol metabolism in vitro and, by doing so, enhance the antiviral response. These results give us the chance to speculate about the suitability of NTZ as adjuvant for induction of specific natural immunity. Moreover, the putative application of NTZ to alimentary-related diseases should be investigated.

Novel Nitro-Heteroaromatic Antimicrobial Agents for the Control and Eradication of Biofilm-Forming Bacteria

The synthesis and biological activity of several novel nitrothiazole, nitrobenzothiazole, and nitrofuran containing antimicrobial agents for the eradication of biofilm-forming Gram-negative and Gram-positive pathogens is described. Nitazoxanide (NTZ), nitrofurantoin, and furazolidone are commercial antimicrobials which were used as models to show how structural modification improved activity toward planktonic bacteria via minimum inhibitory concentration (MIC) assays and biofilms via minimum biofilm eradication concentration (MBEC) assays. Structure–activity relationship (SAR) studies illustrate the ways in which improvements have been made to the aforementioned antimicrobial agents. It is of particular interest in this regard that the introduction of a chloro substituent at the 5-position of NTZ (analog 1b) resulted in marked activity enhancement, as did the replacement of the 2-acetoxy substituent in the latter compound with a basic amine group (analog 7b). It is also of importance that analog 4a, which is a simple methacrylamide, displayed noteworthy activity against S. epidermidis biofilms. These lead compounds identified to have high activity towards biofilms provide promise as starting points in future pro-drug studies.

Nitazoxanide superiority to placebo to treat moderate COVID-19 - A Pilot prove of concept randomized double-blind clinical trial.

BackgroundThe absence of specific antivirals to treat COVID-19 leads to the repositioning of candidates’ drugs. Nitazoxanide (NTZ) has a broad antiviral effect.MethodsThis was a randomized, double-blind pilot clinical trial comparing NTZ 600 mg BID versus Placebo for seven days among 50 individuals (25 each arm) with SARS-COV-2 RT-PCR+ (PCR) that were hospitalized with mild respiratory insufficiency from May 20th, 2020, to September 21st, 2020 (ClinicalTrials.gov NCT04348409). Clinical and virologic endpoints and inflammatory biomarkers were evaluated. A five-point scale for disease severity (SSD) was used.FindingsTwo patients died in the NTZ arm compared to 6 in the placebo arm (p = 0.564). NTZ was superior to placebo when considering SSD (p < 0001), the mean time for hospital discharge (6.6 vs. 14 days, p = 0.021), and negative PCR at day 21 (p = 0.035), whereas the placebo group presented more adverse events (p = 0.04). Among adverse events likely related to the study drug, 14 were detected in the NTZ group and 22 in placebo (p = 0.24). Among the 30 adverse events unlikely related, 21 occurred in the placebo group (p = 0.04). A decrease from baseline was higher in the NTZ group for d-Dimer (p = 0.001), US-RCP (p < 0.002), TNF (p < 0.038), IL-6 (p < 0.001), IL-8 (p = 0.014), HLA DR. on CD4+T lymphocytes (p < 0.05), CD38 in CD4+ and CD8+T (both p < 0.05), and CD38 and HLA-DR. on CD4+ (p < 0.01)InterpretationCompared to placebo in clinical and virologic outcomes and improvement of inflammatory outcomes, the superiority of NTZ warrants further investigation of this drug for moderate COVID-19 in larger clinical trials. A higher incidence of adverse events in the placebo arm might be attributed to COVID-19 related symptoms.

Nitazoxanide impairs mitophagy flux through ROS-mediated mitophagy initiation and lysosomal dysfunction in bladder cancer

Bladder cancer is one of the most common malignancy in the urinary tract with high recurrence and drug resistance in clinics. Alternative treatments from existing drugs might be a promising strategy. Nitazoxanide (NTZ), an FDA-approved antiprotozoal drug, has got increasingly noticed because of its favorable safety profile and antitumor potential, yet the effects in bladder cancer and underlying mechanisms remain poorly understood. Herein, we find that NTZ induces mitochondrial damage and mitophagy initiation through PINK1-generated phospho-ubiquitin(pS65-Ub) and autophagy receptor-mediated pathway even in the absence of Atg5/Beclin1. Meanwhile, NTZ inhibits lysosomal degradation activity, leading to mitophagy flux impairment at late stage. Mitochondrial reactive oxygen species (ROS) production is critical in this process, as eliminating ROS with N-acetylcysteine (NAC) efficiently inhibits PINK1 signaling-mediated mitophagy initiation and alleviates lysosomal dysfunction. Co-treatment with NTZ and autophagy inhibitor Chloroquine (CQ) to aggravate mitophagy flux impairment promotes NTZ-induced apoptosis, while alleviation of mitophagy flux impairment with ROS scavenger reduces cell death. Moreover, we also discover a similar signaling response in the 3D bladder tumor spheroid after NTZ exposure. In vivo study reveals a significant inhibition of orthotopic bladder tumors with no obvious systemic toxicity. Together, our results uncover the anti-tumor activities of NTZ with the involvement of ROS-mediated mitophagy modulation at different stages and demonstrate it as a potential drug candidate for fighting against bladder tumors.

Synthesis, in vitro bioassays, and computational study of heteroaryl nitazoxanide analogs.

Antiprotozoal drug nitazoxanide (NTZ) has shown diverse pharmacological properties and has appeared in several clinical trials. Herein we present the synthesis, characterization, in vitro biological investigation, and in silico study of four hetero aryl amide analogs of NTZ. Among the synthesized molecules, compound 2 and compound 4 exhibited promising antibacterial activity against Escherichia coli (E. coli), superior to that displayed by the parent drug nitazoxanide as revealed from the in vitro antibacterial assay. Compound 2 displayed zone of inhibition of 20 mm, twice as large as the parent drug NTZ (10 mm) in their least concentration (12.5 µg/ml). Compound 1 also showed antibacterial effect similar to that of nitazoxanide. The analogs were also tested for in vitro cytotoxic activity by employing cell counting kit‐8 (CCK‐8) assay technique in HeLa cell line, and compound 2 was identified as a potential anticancer agent having IC50 value of 172 µg which proves it to be more potent than nitazoxanide (IC50 = 428 µg). Furthermore, the compounds were subjected to molecular docking study against various bacterial and cancer signaling proteins. The in vitro test results corroborated with the in silico docking study as compound 2 and compound 4 had comparatively stronger binding affinity against the proteins and showed a higher docking score than nitazoxanide toward human mitogen‐activated protein kinase (MAPK9) and fatty acid biosynthesis enzyme (FabH) of E. coli. Moreover, the docking study demonstrated dihydrofolate reductase (DHFR) and thymidylate synthase (TS) as probable new targets for nitazoxanide and its synthetic analogs. Overall, the study suggests that nitazoxanide and its analogs can be a potential lead compound in the drug development.

Nitazoxanide versus rifaximin in preventing the recurrence of hepatic encephalopathy: A randomized double-blind controlled trial.

Hepatic encephalopathy (HE) is a neuropsychiatric complication of liver cirrhosis. HE is associated with poor survival and detrimental effects on quality of life (QOL). The drawbacks of the long-term use of rifaximin in HE necessitates searching for alternative therapies. In this context, our study aimed at evaluating the safety and efficacy of nitazoxanide (NTZ) as compared to rifaximin (RFX) in preventing the recurrence of HE and assessing its impact on QOL. This prospective, randomized, double-blind controlled study included 60 patients who were randomly assigned to receive either rifaximin 550mg twice daily (group 1; n=30) or nitazoxanide 500mg twice daily (group 2; n=30) for 24weeks. During the study period, the patients' neurological symptoms, mental status, and performance were monitored. The serum levels of HE triggers (ammonia, TNF-α, and octopamine) were assessed. The patients' health-related quality of life was also evaluated. Six months after treatment, patients on NTZ therapy showed a statistically significant improvement in CHESS score and mental status. NTZ provided 136days of remission vs 67days of remission for patients on RFX (P1 =.0001) and significant reduction in Child score (P1 =.018). Additionally, NTZ showed a statistically significant decrease in serum ammonia, TNF-α, and octopamine levels as compared to rifaximin. Regarding QOL, NTZ group showed an improvement in total Chronic Liver Disease Questionnaire (CLDQ) score. Both groups experienced minor controllable side effects. Nitazoxanide may represent a suitable and safe alternative therapy to rifaximin in preventing the recurrence of hepatic encephalopathy.

ROLE OF APOPTOSIS IN EXPERIMENTAL CRYPTOSPORIDIUM PARVUM INFECTED ALBINO MICE

Cryptosporidium is one of the commonest opportunistic parasites. But, its chemotherapeuticoptions are limited, with controversy about the role of apoptosis in cryptosporidiosis. Caspasesare key molecules of apoptosis. The study assessed the role of apoptosis in cryptosporidiosisby studying the relationship between the effects of phenyl vinyl sulfone (PVS), nitazoxanide(NTZ) and combined therapy on Cryptosporidium parvum infection and caspase 3immunostaining. Ninety female laboratory bred Swiss Albino mice were divided into twomajor groups; immunocompetent and immunosuppressed. Both groups were divided into thefollowing subgroups, for each one respectively: negative control (1 & 6), infected control (2& 7), infected treated with PVS (3 & 8), infected treated with NTZ (4 & 9) and infected treatedcombined (5 & 10). Sacrification were done on 18th day post infection.Histopathological study of ileum was done and endogenous developmental stages werecounted. Also, caspase 3 immunohistochemical staining was carried out on ileal sections.Combined therapy in groups 5 &10 showed the highest reduction in mean number of endogenousdevelopmental stages as in G10 (P <0.05). Caspase expression in PVS treated groups (3& 8) showed significant decrease when compared to their control groups (P < 0.05). Whilethere were significant increase in caspase expression in groups treated with NTZ (4 & 9)when compared to their contorls (P < 0.05). Caspase 3 epithelial overexpression was evidentin infected immunocompetent G2 than immunosuppressed G7 (P<0.05).

Structure-Activity Study of Nitazoxanide Derivatives as Novel STAT3 Pathway Inhibitors.

We identified nitazoxanide (NTZ) as a moderate STAT3 pathway inhibitor through immunoblot analysis and a cell-based IL-6/JAK/STAT3 pathway activation assay. A series of thiazolide derivatives were designed and synthesized to further validate the thiazolide scaffold as STAT3 inhibitors. Eight out of 25 derivatives displayed potencies greater than that of NTZ, and their STAT3 pathway inhibitory activities were found to be significantly correlated with their antiproliferative activities in HeLa cells. Derivatives 15 and 24 were observed to be more potent than the positive control WP1066, which is under phase I clinical trials. Compared with NTZ, 15 also exhibited much improved in vivo pharmacokinetic parameters in rats and efficacies against proliferations in multiple cancer cell lines, indicating a broad-spectrum effect of these thiazolides as antitumor agents targeted on STAT3.

Systemic efficacy on Cryptosporidium parvum infection of aminoxanide (RM-5061), a new amino-acid ester thiazolide prodrug of tizoxanide.

Cryptosporidiosis is a gastrointestinal illness with profuse diarrhoea. Although there are no other Food and Drug Administration (FDA)-approved alternatives for the treatment of cryptosporidiosis, nitazoxanide (NTZ) can be qualified as partially effective. In immunosuppressed conditions, severe and/or disseminated cryptosporidiosis may occur and patients should be treated parenterally. To achieve the goal of developing parenteral treatment for cryptosporidiosis, the current study was undertaken to investigate the in vitro and in vivo anticryptosporidial activity of aminoxanide. This new l-tert-leucyl thiazolide is a soluble prodrug of tizoxanide (TIZ), the main metabolite of NTZ. Confirming the good efficacy of aminoxanide in Cryptosporidium parvum-infected HCT-8 cells with a 50% inhibitory concentration of 1.55 μm (±0.21), in immunosuppressed C. parvum-infected Mongolian gerbils (Meriones unguiculatus), a 5-day treatment with a daily intramuscular dose of 100 mg kg−1 aminoxanide resulted in a 72.5% oocyst excretion inhibition, statistically equivalent to 75.5% in gerbils treated with a 4-fold lower oral dose of NTZ. Cryptosporidium parvum-induced intestinal pathology and inflammation were improved. Aminoxanide provides an injectable form of TIZ that NTZ was unable to do and is a promising drug for which optimization of the formulation should be further explored. These results represent a first promising step towards the goal of developing a parenteral treatment for cryptosporidiosis.

Mechanochemical synthesis of a novel eutectic of the antimicrobial nitazoxanide with improved dissolution performance

Background: Nitazoxanide (NTZ) is a broad spectrum antimicrobial agent with poor aqueous solubility and low bioavailability. Thus, the generation of new solid forms of NTZ is relevant to improve its unfavorable properties. The present study deals with the application of mechanochemistry for the preparation of alternate solid forms of NTZ, using saccharine (SAC) as coformer. Methods: NTZ-SAC mixtures were prepared by neat and liquid-assisted grinding (LAG) and characterized using differential scanning calorimetry (DSC), hot stage microscopy (HSM), X-ray Powder Diffraction (XRPD), 13C Solid-state Nuclear Magnetic Resonance (SSNMR) and Diffuse Reflectance Infrared Fourier Transform (DRIFT) spectroscopy. Powder dissolution (PD) profiles were obtained with USP apparatus 2 in buffer phosphate pH 6.5 with 0.25% Tween 80 - 0.25% triethanolamine and in 0.25% sodium lauryl sulfate, at 37 ºC ± 0.5 ºC and 75 rpm. Drug release was characterized in terms of dissolution efficiency (DE). Results: XRPD, SSNMR and DRIFT indicated that NTZ and SAC did not cocrystallize but DSC and HSM revealed that they formed a binary eutectic mixture which melted near 176 °C, a melting temperature lower than those of NTZ and SAC. PD data indicated that the 1:1 NTZ-SAC sample obtained by LAG exhibited a slightly higher DE than pure NTZ in the two assayed media. Conclusion: NTZ and SAC formed a eutectic, the first reported for this drug, which improved its dissolution rate and opened the pathway for studies searching for new eutectics with better biopharmaceutical attributes than NTZ and the NTZ-SAC eutectic reported herein.

Transmucosal Delivery of Self-Assembling Photosensitizer-Nitazoxanide Nanocomplexes with Fluorinated Chitosan for Instillation-Based Photodynamic Therapy of Orthotopic Bladder Tumors.

Theoretically, on account of improved local bioavailability of photosensitizers and attenuated systemic phototoxicity, intravesical instillation-based photodynamic therapy (PDT) for bladder cancer (BCa) would demonstrate significant advantages in comparison with the intravenous route. Actually, the low transmucosal efficiency, hypoxia regulation deficiency, as well as the biosafety risks of intravesical drug agents all have greatly limited the clinical development of instillation-based PDT for BCa. Herein, based on our recent findings on bladder intravesical vectors and photodynamic treatment, we explore and find that the conventional antiparasitic agent nitazoxanide (NTZ) by mixing with chlorine e6 (Ce6) conjugated human serum albumin (HSA), HSA-Ce6, is capable of forming self-assembled HSA-Ce6/NTZ nanoparticles (NPs). Then, the HSA-Ce6/NTZ complexes further fabricate with fluorinated chitosan (FCS), the synthesized transmucosal carrier, to form a biocompatible nanoscale system HSA-Ce6/NTZ/FCS NPs, which exhibit remarkably improved transmucosal delivery and uptake capacities compared with HSA-Ce6/NTZ alone or non-fluorinated HSA-Ce6/NTZ/CS NPs. Meanwhile, due to the metabolic regulation of tumor cells by NTZ, the tumor hypoxia could be efficaciously ameliorated to further favor PDT. This work represents a new photosensitizer nanomedicine formulation for the perfection of PDT performance through the modulation of tumor hypoxia by clinically approved agents. Thus, intravesical instillation of HSA-Ce6/NTZ/FCS NPs with favorable biocompatibility, followed by cystoscope-mediated PDT, could achieve a dramatically improved therapeutic effect to ablate orthotopic bladder tumors.

Human Astroviruses: A Tale of Two Strains.

Since the 1970s, eight closely related serotypes of classical human astroviruses (HAstV) have been associated with gastrointestinal illness worldwide. In the late 2000s, three genetically unique human astrovirus clades, VA1-VA3, VA2-VA4, and MLB, were described. While the exact disease associated with these clades remains to be defined, VA1 has been associated with central nervous system infections. The discovery that VA1 could be grown in cell culture, supports exciting new studies aimed at understanding viral pathogenesis. Given the association of VA1 with often lethal CNS infections, we tested its susceptibility to the antimicrobial drug, nitazoxanide (NTZ), which we showed could inhibit classical HAstV infections. Our studies demonstrate that NTZ inhibited VA1 replication in Caco2 cells even when added at 12 h post-infection, which is later than in HAstV-1 infection. These data led us to further probe VA1 replication kinetics and cellular responses to infection in Caco-2 cells in comparison to the well-studied HAstV-1 strain. Overall, our studies highlight that VA1 replicates more slowly than HAstV-1 and elicits significantly different cellular responses, including the inability to disrupt cellular junctions and barrier permeability.

The immunomodulatory activity of secnidazole-nitazoxanide in a murine cryptosporidiosis model.

Introduction. Cryptosporidium parvum causes intestinal parasitic infections affecting both immunosuppressed and immunocompetent individuals.Gap statement. Given the absence of effective treatments for cryptosporidiosis, especially in immunodeficient patients, the present study was designed to assess the therapeutic efficacy of secnidazole (SEC) and its combination with nitazoxanide (NTZ) in comparison to single NTZ treatment in relation to the immune status of a murine model of C. parvum infection.Methodology. The infected groups were administered NTZ, SEC or NTZ-SEC for three or five successive doses. At days 10 and 12 post-infection (p.i.), the mice were sacrificed, and the efficacy of the applied drugs was evaluated by comparing the histopathological alterations in ileum and measuring the T helper Th1 (interferon gamma; IFN-γ), Th2 [interleukin (IL)-4 and IL-10] and Th17 (IL-17) cytokine profiles in serum.Results. The NTZ-SEC combination recorded the maximal reduction of C. parvum oocyst shedding, endogenous stages count and intestinal histopathology, regardless of the immune status of the infected mice. The efficacy of NTZ-SEC was dependent on the period of administration, as the 5 day-based treatment protocol was also more effective than the 3 day-based one in terms of immunocompetence and immunosuppression. The present treatment schedule induced an immunomodulatory effect from SEC that developed a protective immune response against C. parvum infection with reduced production of serum IL-17, IFN-γ, IL-4 and IL-10.Conclusions. Application of NTZ-SEC combined therapy may be useful in treatment of C. parvum, especially in cases involving immunosuppression.

From hydroxychloroquine to ivermectin: what are the anti-viral properties of anti-parasitic drugs to combat SARS-CoV-2?

BackgroundNearly a year into the COVID-19 pandemic, we still lack effective anti-SARS-CoV-2 drugs with substantial impact on mortality rates except for dexamethasone. As the search for effective antiviral agents continues, we aimed to review data on the potential of repurposing antiparasitic drugs against viruses in general, with an emphasis on coronaviruses.MethodsWe performed a review by screening in vitro and in vivo studies that assessed the antiviral activity of several antiparasitic agents: chloroquine, hydroxychloroquine (HCQ), mefloquine, artemisinins, ivermectin, nitazoxanide (NTZ), niclosamide, atovaquone and albendazole.ResultsFor HCQ and chloroquine we found ample in vitro evidence of antiviral activity. Cohort studies that assessed the use of HCQ for COVID-19 reported conflicting results, but randomized controlled trials (RCTs) demonstrated no effect on mortality rates and no substantial clinical benefits of HCQ used either for prevention or treatment of COVID-19. We found two clinical studies of artemisinins and two studies of NTZ for treatment of viruses other than COVID-19, all of which showed mixed results. Ivermectin was evaluated in one RCT and few observational studies, demonstrating conflicting results. As the level of evidence of these data is low, the efficacy of ivermectin against COVID-19 remains to be proven. For chloroquine, HCQ, mefloquine, artemisinins, ivermectin, NTZ and niclosamide, we found in vitro studies showing some effects against a wide array of viruses. We found no relevant studies for atovaquone and albendazole.ConclusionsAs the search for an effective drug active against SARS-CoV-2 continues, we argue that pre-clinical research of possible antiviral effects of compounds that could have antiviral activity should be conducted. Clinical studies should be conducted when sufficient in vitro evidence exists, and drugs should be introduced into widespread clinical use only after being rigorously tested in RCTs. Such a search may prove beneficial in this pandemic or in outbreaks yet to come.

Assessment of chitosan nanoparticles in improving the efficacy of nitazoxanide on cryptosporidiosis in immunosuppressed and immunocompetent murine models.

Cryptosporidiosis is one of the major causes of diarrhea in immunocompetent and immunocompromised patients. It is self-limited in immunocompetent individuals. However, in the immunocompromised it can cause life-threatening diarrhea and results in chronic malabsorption of fluids, vitamins and electrolytes resulting in wasting. Our study is concerned with assessing and comparing the efficacy of nitazoxanide (NTZ) alone and NTZ loaded chitosan nanoparticles (NTZ loaded CS NPs) in the treatment of experimental cryptosporidiosis using parasitological and histopathological parameters. One hundred mice were divided into 5 groups (20 mice each). Each group was divided into 2 subgroups according to the immune status [a-immunocompetent, b-immunosuppressed]. group 1: control (healthy), group 2: control infected by Cryptosporidium oocysts, group 3: infected treated by NTZ, group 4: infected then treated by NTZ loaded CS NPs and group 5: infected then treated by chitosan nanoparticles (CS NPs) alone. Treatment of Cryptosporidium infected mice with NTZ loaded on CS NPs resulted in the highest significant reduction in oocysts shedding in both immunocompetent and immunosuppressed groups followed by treatment with NTZ form then by treatment with CS NPs alone. The treatment with NTZ loaded CS NPs displayed a remarkable improvement of the histopathological changes of the intestine, liver and lung while NTZ treated group showed some improvement. Treatment with NTZ loaded CS NPs in murine cryptosporidiosis gave the best results as it caused marked reduction in fecal oocysts counts and improvement of histopathological changes in immunocompetent and immunosuppressed groups.

Antiparasitic and immunomodulating effects of nitazoxanide, ivermectin and selenium on Cryptosporidium infection in diabetic mice.

The present work aims to investigate the antiparasitic and the immunomodulating effects of nitazoxanide (NTZ) and ivermectin (IVC) alone or combined together or combined with selenium (Se), on Cryptosporidium infection in diabetic mice. The results revealed that the combined NTZ and IVC therapy achieved the highest reduction of fecal oocysts (92%), whereas single NTZ showed the lowest reduction (63%). Also, adding Se to either NTZ or IVC resulted in elevation of oocyst reduction from 63% to 71% and from 82% to 84% respectively. All treatment regimens, with the exception of NTZ monotherapy, showed a significant improvement in the intestinal histopathology, the highest score was in combined NTZ and IVC therapy. The unique results of immunohistochemistry in this study showed reversal of the normal CD4/CD8 T cell ratio in the infected untreated mice, however, following therapy it reverts back to a normal balanced ratio. The combined (NTZ+ IVC) treatment demonstrated the highest level of CD4 T cell expression. Taken together, NTZ and IVC combined therapy showed remarkable anti-parasitic and immunostimulatory effects, specifically towards the CD4 population that seem to be promising in controlling cryptosporidiosis in diabetic individuals. Further research is required to explore other effective treatment strategies for those comorbid patients.

Nitazoxanide &lt;i&gt;In Vitro&lt;/i&gt; Efficacy Against SARS CoV-2 and &lt;i&gt; In Vivo&lt;/i&gt; Superiority to Placebo to Treat Moderate COVID-19 – A Phase 2 Randomized Double-Blind Clinical Trial

Background: The absence of specific antivirals to treat COVID-19 leads to the repositioning of candidates’ drugs. Nitazoxanide (NTZ) has a broad antiviral effect.Methods: The in vitro effect of NTZ in VERO E6 cells was evaluated, followed by a randomized double-blind phase two clinical trial comparing NTZ 600 mg BID versus placebo for 7 days among 50 individuals (25 each arm) with SARS-COV-2 RT-PCR+ (PCR) that were hospitalized with mild respiratory insufficiency. Clinical and virologic end-points and inflammatory biomarkers were evaluated. A five-point scale for disease severity (SSD) was used.Results: The in vitro inhibition of SARS-CoV-2 infection was 90% with 0.5 µM, with no cytotoxicity. Two patients died in the NTZ arm compared to 6 in the placebo arm (p=NS). NTZ was superior to placebo when considering SSD (pConclusions: The superiority of NTZ as compared to placebo in clinical and virologic outcomes, as wells as improvement of inflammatory outcomes, warrants further investigation of this drug for moderate COVID-19 in larger clinical trials. A higher incidence of adverse events in the placebo arm might be attributed to COVID-19 related symptoms.Trial Registration: This study was registered at ClinicalTrials.gov (NCT04348409).Funding Statement: This clinical trial was funded by FQM Farma.Declaration of Interests: AL has received grants and personal fees from Janssen Pharmaceutical;has received personal fees from Daiichi Sankyo, Cristalia Produtos Quımicos e Farmaceuticos, Libbs, Pfizer, Myralis Farma, Ache Laboratorios, Hypera Pharma, and Sanofi-Aventis; and has received grants from FQM Farma, Eli Lilly, H. Lundbeck A/S, Servier Laboratories, Hoffman-La Roche, Biophytis, and Forum Pharmaceutical. All other authors have nothing to declare. Ethics Approval Statement: This trial was approved by the Brazilian National Institutional Review Board (CONEP; approval # CAAE- 30628420.0.0000.5412) and each local Institutional Review Boards. Informed consent has been obtained.