The clinical antiprotozoal drug nitazoxanide and its metabolite tizoxanide extend Caenorhabditis elegans lifespan and healthspan.

The drugs extending healthspan in clinic have always been searched. Nitazoxanide is an FDA-approved clinical antiprotozoal drug. Nitazoxanide is rapidly metabolized to tizoxanide after absorption in vivo. Our previous studies find that nitazoxanide and its metabolite tizoxanide induce mild mitochondrial uncoupling and activate cellular AMPK, oral nitazoxanide protects against experimental hyperlipidemia, hepatic steatosis, and atherosclerosis. Here, we demonstrate that both nitazoxanide and tizoxanide extend the lifespan and healthspan of Caenorhabditis elegans through Akt/AMPK/sir 2.1/daf16 pathway. Additionally, both nitazoxanide and tizoxanide improve high glucose-induced shortening of C. elegans lifespan. Nitazoxanide has been a clinical drug with a good safety profile, we suggest that it is a novel anti-aging drug.

Non-linear plasma protein binding of cannabidiol.

BACKGROUND: Cannabidiol is highly bound to plasma proteins. Changes in its protein binding can lead to altered unbound plasma concentrations and result in alteration of pharmacological activity of cannabidiol-containing medications. This research has assessed non-linearity of cannabidiol plasma protein binding and the potential effect of tizoxanide on the binding. METHOD: Cannabidiol protein binding was evaluated by ultrafiltration technique. Human plasma was spiked with cannabidiol stock solution to produce samples of various concentrations. For interaction study potential interactant tizoxanide was added in each sample. All samples were processed through Amicon Micropartition system and analyzed by HPLC. RESULTS: The study has detected cannabidiol binding to borosilicate glass (9%) and polyethylene plastics (15%). In the interaction study the mean protein unbound fraction of cannabidiol was 0.05 (5%), indicating no binding interaction between cannabidiol and tizoxanide since cannabidiol unbound fraction without tizoxanide was also 5%. The cannabidiol fraction unbound was more than 2-fold greater at high concentrations compared to low concentrations. CONCLUSION: a). At high concentrations cannabidiol plasma protein binding is non-linear. The non-linearity can affect elimination and medicinal effect of cannabidiol drugs. b). Borosilicate and polyethylene containers should be avoided in formulation, packing and administration of cannabidiol-containing medicines to guarantee correct doses. c). Cannabidiol medications can be co-administered with tizoxanide without caution.

Glucuronidation of tizoxanide, an active metabolite of nitazoxanide, in liver and small intestine: Species differences in humans, monkeys, dogs, rats, and mice and responsible UDP-glucuronosyltransferase isoforms in humans.

Tizoxanide (TZX) is an active metabolite of nitazoxanide (NTZ) originally developed as an antiparasitic agent, and is predominantly metabolized into TZX glucuronide. In the present study, TZX glucuronidation by the liver and intestinal microsomes of humans, monkeys, dogs, rats, and mice, and recombinant human UDP-glucuronosyltransferase (UGT) were examined. The kinetics of TZX glucuronidation by the liver and intestinal microsomes followed the Michaelis-Menten or biphasic model, with species-specific variations in the intrinsic clearance (CLint). Rats and mice exhibited the highest CLint values for liver microsomes, while mice and rats were the highest for intestinal microsomes. Among human UGTs, UGT1A1 and UGT1A8 demonstrated significant glucuronidation activity. Estradiol and emodin inhibited TZX glucuronidation activities in the human liver and intestinal microsomes in a dose-dependent manner, with emodin showing stronger inhibition in the intestinal microsomes. These results suggest that the roles of UGT enzymes in TZX glucuronidation in the liver and small intestine differ extensively across species and that UGT1A1 and/or UGT1A8 mainly contribute to the metabolism and elimination of TZX in humans. This study presents the relevant and novel-appreciative report on TZX metabolism catalyzed by UGT enzymes, which may aid in the assessment of the antiparasitic, antibacterial, and antiviral activities of NTZ for the treatment of various infections.

The antiprotozoal drug nitazoxanide improves experimental liver fibrosis in mice.

Nitazoxanide is an FDA-approved antiprotozoal drug. Our previous studies find that nitazoxanide and its metabolite tizoxanide affect AMPK, STAT3, and Smad2/3 signals which are involved in the pathogenesis of liver fibrosis, therefore, in the present study, we examined the effect of nitazoxanide on experimental liver fibrosis and elucidated the potential mechanisms. The in vivo experiment results showed that oral nitazoxanide (75, 100 mg·kg-1) significantly improved CCl4- and bile duct ligation-induced liver fibrosis in mice. Oral nitazoxanide activated the inhibited AMPK and inhibited the activated STAT3 in liver tissues from liver fibrosis mice. The in vitro experiment results showed that nitazoxanide and its metabolite tizoxanide activated AMPK and inhibited STAT3 signals in LX-2 cells (human hepatic stellate cells). Nitazoxanide and tizoxanide inhibited cell proliferation and collagen I expression and secretion of LX-2 cells. Nitazoxanide and tizoxanide inhibited transforming growth factor-ß1 (TGF-ß1)- and IL-6-induced increases of cell proliferation, collagen I expression and secretion, inhibited TGF-ß1- and IL-6-induced STAT3 and Smad2/3 activation in LX-2 cells. In mouse primary hepatic stellate cells, nitazoxanide and tizoxanide also activated AMPK, inhibited STAT3 and Smad2/3 activation, inhibited cell proliferation, collagen I expression and secretion. In conclusion, nitazoxanide inhibits liver fibrosis and the underlying mechanisms involve AMPK activation, and STAT3 and Smad2/3 inhibition.

Nitazoxanide protects against experimental ulcerative colitis through improving intestinal barrier and inhibiting inflammation.

Ulcerative colitis is a chronic disease with colonic mucosa injury. Nitazoxanide is an antiprotozoal drug in clinic. Nitazoxanide and its metabolite tizoxanide have been demonstrated to activate AMPK and inhibit inflammation, therefore, the aim of the present study is to investigate the effect of nitazoxanide on dextran sulfate sodium (DSS)-induced colitis and the underlying mechanism. Oral administration of nitazoxanide ameliorated the symptoms of mice with DSS-induced colitis, as evidenced by improving the increased disease activity index (DAI), the decreased body weight, and the shortened colon length. Oral administration of nitazoxanide ameliorated DSS-induced intestinal barrier dysfunction and reduced IL-6 and IL-17 expression in colon tissues. Mechanistically, nitazoxanide and its metabolite tizoxanide treatment activated AMPK and inhibited JAK2/STAT3 signals. Nitazoxanide and tizoxanide treatment increased caudal type homeobox 2 (CDX2) expression, increased alkaline phosphatase (ALP) activity and promoted tight junctions in Caco-2 cells. Nitazoxanide and tizoxanide treatment restored the decreased zonula occludens-1(ZO-1) and occludin protein levels induced by LPS or IL-6 in Caco-2 cells. On the other hand, nitazoxanide and tizoxanide regulated macrophage bias toward M2 polarization, as evidenced by the increased arginase-1expression in bone marrow-derived macrophages (BMDM). Nitazoxanide and tizoxanide reduced the increased IL-6, iNOS and CCL2 pro-inflammatory gene expressions and inhibited JAK2/STAT3 activation in BMDM induced by LPS. In conclusion, nitazoxanide protects against DSS-induced ulcerative colitis in mice through improving intestinal barrier and inhibiting inflammation and the underlying mechanism involves AMPK activation and JAK2/STAT3 inhibition.

Tizoxanide as a novel theraputic candidate for osteoarthritis.

Osteoarthritis (OA) is a frequently seen degenerative joint disease in the elderly. Its pathogenesis is highly related to the local inflammatory reaction and autophagy. Tizoxanide (Tiz), the main active metabolite of nitazoxanide, has proved its anti-inflammatory properties in several diseases. However, the exact role of Tiz in OA remains to explore. In this study, we investigated the anti-arthritic effects and the underlying molecular mechanisms of Tiz on rat OA. The results showed that Tiz could attenuate the IL-1ß-induced inflammatory disorders, cartilage matrix damage and autophagy reduction in rat chondrocytes. Moreover, employment of autophagy inhibitor 3-methyladenine (3-MA) could antagonize the protective effects of Tiz in IL-1ß-treated rat chondrocytes. Additionally, Tiz also inhibited the IL-1ß-induced PI3K/AKT/mTOR and P38/JNK phosphorylation in chondrocytes. In vivo, intra-articular injection of Tiz could significantly alleviate the progression of cartilage damage in rat OA model. Briefly, our study demonstrated the therapeutic potential of Tiz in OA, suggesting that Tiz administration might serve as a promising strategy in OA therapy.

Anthelmintic nitazoxanide protects against experimental pulmonary fibrosis.

BACKGROUND AND PURPOSE: Nitazoxanide is a therapeutic anthelmintic drug. Our previous studies found that nitazoxanide and its metabolite tizoxanide activated adenosine 5'-monophosphate-activated protein kinase (AMPK) and inhibited signal transducer and activator of transcription 3 (STAT3) signals. As AMPK activation and/or STAT3 inhibition are targets for treating pulmonary fibrosis, we hypothesized that nitazoxanide would be effective in experimental pulmonary fibrosis. EXPERIMENTAL APPROACH: The mitochondrial oxygen consumption rate of cells was measured by using the high-resolution respirometry system Oxygraph-2K. The mitochondrial membrane potential of cells was evaluated by tetramethyl rhodamine methyl ester (TMRM) staining. The target protein levels were measured by using western blotting. The mice pulmonary fibrosis model was established through intratracheal instillation of bleomycin. The examination of the lung tissues changes were carried out using haematoxylin and eosin (H&E), and Masson staining. KEY RESULTS: Nitazoxanide and tizoxanide activated AMPK and inhibited STAT3 signalling in human lung fibroblast cells (MRC-5 cells). Nitazoxanide and tizoxanide inhibited transforming growth factor-ß1 (TGF-ß1)-induced proliferation and migration of MRC-5 cells, collagen-I and α-smooth muscle cell actin (α-SMA) expression, and collagen-I secretion from MRC-5 cells. Nitazoxanide and tizoxanide inhibited epithelial-mesenchymal transition (EMT) and inhibited TGF-ß1-induced Smad2/3 activation in mouse lung epithelial cells (MLE-12 cells). Oral administration of nitazoxanide reduced the bleomycin-induced mice pulmonary fibrosis and, in the established bleomycin-induced mice, pulmonary fibrosis. Delayed nitazoxanide treatment attenuated the fibrosis progression. CONCLUSIONS AND IMPLICATIONS: Nitazoxanide improves the bleomycin-induced pulmonary fibrosis in mice, suggesting a potential application of nitazoxanide for pulmonary fibrosis treatment in the clinic.

Quantitation of tizoxanide in multiple matrices to support cell culture, animal and human research.

Currently nitazoxanide is being assessed as a candidate therapeutic for SARS-CoV-2. Nitazoxanide is rapidly broken down to its active metabolite tizoxanide upon administration. Unlike many other candidates being investigated, tizoxanide plasma concentrations achieve antiviral levels after administration of the approved dose, although higher doses are expected to be needed to maintain these concentrations across the dosing interval in the majority of patients. Here an LC-MS/MS assay is described that has been validated in accordance with Food and Drug Administration (FDA) guidelines. Fundamental parameters have been evaluated, and these included accuracy, precision and sensitivity. The assay was validated for human plasma, mouse plasma and Dulbecco's Modified Eagles Medium (DMEM) containing varying concentrations of Foetal Bovine Serum (FBS). Matrix effects are a well-documented source of concern for chromatographic analysis, with the potential to impact various stages of the analytical process, including suppression or enhancement of ionisation. Herein a validated LC-MS/MS analytical method is presented capable of quantifying tizoxanide in multiple matrices with minimal impact of matrix effects. The validated assay presented here was linear from 15.6 ng/mL to 1000 ng/mL. The presented assay here has applications in both pre-clinical and clinical research and may be used to facilitate further investigations into the application of nitazoxanide against SARS-CoV-2.

Tizoxanide Antiviral Activity on Dengue Virus Replication.

Dengue virus is an important circulating arbovirus in Brazil responsible for high morbidity and mortality worldwide, representing a huge economic and social burden, in addition to affecting public health. In this study, the biological activity, toxicity, and antiviral activity against dengue virus type 2 (DENV-2) of tizoxanide (TIZ) was evaluated in Vero cell culture. TIZ has a broad spectrum of action in inhibiting different pathogens, including bacteria, protozoa, and viruses. Cells were infected for 1 h with DENV-2 and then treated for 24 h with different concentrations of the drug. The quantification of viral production indicated the antiviral activity of TIZ. The protein profiles in infected Vero cells treated and not treated with TIZ were analyzed using the label-free quantitative proteomic approach. TIZ was able to inhibit virus replication mainly intracellularly after DENV-2 penetration and before the complete replication of the viral genome. Additionally, the study of the protein profile of infected not-treated and infected-treated Vero cells showed that TIZ interferes with cellular processes such as intracellular trafficking and vesicle-mediated transport and post-translational modifications when added after infection. Our results also point to the activation of immune response genes that would eventually lead to a decrease of DENV-2 production. TIZ is a promising therapeutic molecule for the treatment of DENV-2 infections.

Repurposing nitazoxanide as a novel anti-atherosclerotic drug based on mitochondrial uncoupling mechanisms.

BACKGROUND AND PURPOSE: The anthelmintic drug nitazoxanide has a mitochondrial uncoupling effect. Mitochondrial uncouplers have been proven to inhibit smooth muscle cell proliferation and migration, inhibit NLRP3 inflammasome activation of macrophages and improve dyslipidaemia. Therefore, we aimed to demonstrate that nitazoxanide would protect against atherosclerosis. EXPERIMENTAL APPROACH: The mitochondrial oxygen consumption of cells was measured by using the high-resolution respirometry system, Oxygraph-2K. The proliferation and migration of A10 cells were measured by using Edu immunofluorescence staining, wound-induced migration and the Boyden chamber assay. Protein levels were measured by using the western blot technique. ApoE (-/-) mice were fed with a Western diet to establish an atherosclerotic model in vivo. KEY RESULTS: The in vitro experiments showed that nitazoxanide and tizoxanide had a mitochondrial uncoupling effect and activated cellular AMPK. Nitazoxanide and tizoxanide inhibited serum- and PDGF-induced proliferation and migration of A10 cells. Nitazoxanide and tizoxanide inhibited NLRP3 inflammasome activation in RAW264.7 macrophages, the mechanism by which involved the AMPK/IκBα/NF-κB pathway. Nitazoxanide and tizoxanide also induced autophagy in A10 cells and RAW264.7 macrophages. The in vivo experiments demonstrated that oral administration of nitazoxanide reduced the increase in serum IL-1ß and IL-6 levels and suppressed atherosclerosis in Western diet-fed ApoE (-/-) mice. CONCLUSION AND IMPLICATIONS: Nitazoxanide inhibits the formation of atherosclerotic plaques in ApoE (-/-) mice fed on a Western diet. In view of nitazoxanide being an antiprotozoal drug already approved by the FDA, we propose it as a novel anti-atherosclerotic drug with clinical translational potential.

A specific turn-on fluorescence probe for determination of nitazoxanide based on feasible oxidation reaction with hypochlorite: Applying cobalt ferrite nanoparticles for pre-concentration and extraction of its metabolite from real urine samples.

Nitazoxanide is an antimicrobial compound that was originally developed as an antiprotozoal drug. Recently nitazoxanide has been identified as broad-spectrum antiviral agent and redirected for the remediation of some respiratory tract viral infections. In this study, the spectrofluorimetric technique has been applied to determine Nitazoxanide (NTX) in tablets or its metabolite, tizoxanide (TZD), in human urine samples. The developed methodology is based on oxidizing NTX (non-fluorescence) into a highly fluorescent product by sodium hypochlorite. The fluorescence emission intensity was measured at 436.5 nm after fluorescence excitation at 362.5 nm. After optimizing all conditions, the analytical procedures and bio-analytical steps were evaluated and validated using ICH and FDA criteria, respectively. The method linearity, LOQ, and LOD values of NTX were 1.0-5.0 µg/mL, 0.434, and 0.143 µg/mL, respectively. The other novelty side of the presented work is the application of cobalt ferrite (CoFe2O4) nanoparticles (NPs) as a magnetic solid-phase for the pre-concentration and extraction process. The synthesized magnetic nanoparticles were characterized by scanning electron microscope and zeta sizer techniques. Finally, the utilized magnetic nanoparticles exhibited good recovery results for pre-concentration and extraction of NTX or its metabolite from spiked and real human urine samples, respectively.

Tizoxanide Promotes Apoptosis in Glioblastoma by Inhibiting CDK1 Activity.

The antiparasitic drug nitazoxanide (NTZ) has received considerable attention for its potential in cancer therapy. In this study, we demonstrate that tizoxanide (TIZ), an active metabolite of NTZ, exhibits antiglioma activity in vitro and in vivo by inducing G2/M cell cycle arrest and apoptosis. In vitro, TIZ dose-dependently inhibited the proliferation of U87, U118, and A172 human glioblastoma (GBM) cells at 48 h with IC50 values of 1.10, 2.31, and 0.73 µM, respectively. Treatment with TIZ (1 and 10 µM) also dose-dependently inhibited the colony formation of these GBM cells and accumulated ROS damage in the nucleus. In silico target fishing combined with network pharmacological disease spectrum analyses of GBM revealed that cycle-dependent kinase 1 (CDK1) is the most compatible target for TIZ and molecular docking by Molecule Operating Environment (MOE) software confirmed it. Mechanistically, TIZ inhibited the phosphorylation of CDK1 at Thr161 and decreased the activity of the CDK1/cyclin B1 complex, arresting the cell cycle at the G2/M phase. TIZ may induce apoptosis via the ROS-mediated apoptotic pathway. In vivo, TIZ suppressed the growth of established subcutaneous and intracranial orthotopic xenograft models of GBM without causing obvious side effects and prolonged the survival of nude mice bearing glioma. Taken together, our results demonstrated that TIZ might be a promising chemotherapy drug in the treatment of GBM.

Anthelmintics nitazoxanide protects against experimental hyperlipidemia and hepatic steatosis in hamsters and mice.

Lipid metabolism disorders contribute to hyperlipidemia and hepatic steatosis. It is ideal to develop drugs simultaneous improving both hyperlipidemia and hepatic steatosis. Nitazoxanide is an FDA-approved oral antiprotozoal drug with excellent pharmacokinetic and safety profile. We found that nitazoxanide and its metabolite tizoxanide induced mild mitochondrial uncoupling and subsequently activated AMPK in HepG2 cells. Gavage administration of nitazoxanide inhibited high-fat diet (HFD)-induced increases of liver weight, blood and liver lipids, and ameliorated HFD-induced renal lipid accumulation in hamsters. Nitazoxanide significantly improved HFD-induced histopathologic changes of hamster livers. In the hamsters with pre-existing hyperlipidemia and hepatic steatosis, nitazoxanide also showed therapeutic effect. Gavage administration of nitazoxanide improved HFD-induced hepatic steatosis in C57BL/6J mice and western diet (WD)-induced hepatic steatosis in Apoe -/- mice. The present study suggests that repurposing nitazoxanide as a drug for hyperlipidemia and hepatic steatosis treatment is promising.

Design, Synthesis, and Pharmacokinetic Evaluation of O-Carbamoyl Tizoxanide Prodrugs.

BACKGROUND: The broad-spectrum antiparasitic drug nitazoxanide (N) has been repositioned as a broad-spectrum antiviral drug. Nitazoxanide's in vivo antiviral activities are mainly attributed to its metabolite-tizoxanide, the deacetylation product of nitazoxanide. In reference to the pharmacokinetic profile of nitazoxanide, we proposed the hypotheses that the low plasma concentrations and the low system exposure of tizoxanide after dosing with nitazoxanide result from significant first-pass effects in the liver. It was thought that this might be due to the unstable acyloxy bond of nitazoxanide. OBJECTIVE: Tizoxanide prodrugs, with the more stable formamyl substituent attached to the hydroxyl group rather than the acetyl group of nitazoxanide, were designed with the thought that they might be more stable in plasma. It was anticipated that these prodrugs might be less affected by the first pass effect, which would improve plasma concentrations and system exposure of tizoxanide. METHOD: These O-carbamoyl tizoxanide prodrugs were synthesized and evaluated in a mouse model for pharmacokinetic (PK) properties and in an in vitro model for plasma stabilities. RESULTS: The results indicated that the plasma concentration and the systemic exposure of tizoxanide (T) after oral administration of O-carbamoyl tizoxanide prodrugs were much greater than that produced by the equimolar dosage of nitazoxanide. It was also found that the plasma concentration and the systemic exposure of tizoxanide glucuronide (TG) were much lower than that produced by nitazoxanide. CONCLUSION: Further analysis showed that the suitable plasma stability of O-carbamoyl tizoxanide prodrugs is the key factor in maximizing the plasma concentration and the systemic exposure of the active ingredient tizoxanide.

Anthelmintics nitazoxanide protects against experimental hyperlipidemia and hepatic steatosis in hamsters and mice

Lipid metabolism disorders contribute to hyperlipidemia and hepatic steatosis. It is ideal to develop drugs simultaneous improving both hyperlipidemia and hepatic steatosis. Nitazoxanide is an FDA-approved oral antiprotozoal drug with excellent pharmacokinetic and safety profile. We found that nitazoxanide and its metabolite tizoxanide induced mild mitochondrial uncoupling and subsequently activated AMPK in HepG2 cells. Gavage administration of nitazoxanide inhibited high-fat diet (HFD)-induced increases of liver weight, blood and liver lipids, and ameliorated HFD-induced renal lipid accumulation in hamsters. Nitazoxanide significantly improved HFD-induced histopathologic changes of hamster livers. In the hamsters with pre-existing hyperlipidemia and hepatic steatosis, nitazoxanide also showed therapeutic effect. Gavage administration of nitazoxanide improved HFD-induced hepatic steatosis in C57BL/6J mice and western diet (WD)-induced hepatic steatosis in Apoe -/- mice. The present study suggests that repurposing nitazoxanide as a drug for hyperlipidemia and hepatic steatosis treatment is promising.

Therapeutic Potential of Nitazoxanide: An Appropriate Choice for Repurposing versus SARS-CoV-2?

The rapidly growing COVID-19 pandemic is the most serious global health crisis since the "Spanish flu" of 1918. There is currently no proven effective drug treatment or prophylaxis for this coronavirus infection. While developing safe and effective vaccines is one of the key focuses, a number of existing antiviral drugs are being evaluated for their potency and efficiency against SARS-CoV-2 in vitro and in the clinic. Here, we review the significant potential of nitazoxanide (NTZ) as an antiviral agent that can be repurposed as a treatment for COVID-19. Originally, NTZ was developed as an antiparasitic agent especially against Cryptosporidium spp.; it was later shown to possess potent activity against a broad range of both RNA and DNA viruses, including influenza A, hepatitis B and C, and coronaviruses. Recent in vitro assessment of NTZ has confirmed its promising activity against SARS-CoV-2 with an EC50 of 2.12 µM. Here we examine its drug properties, antiviral activity against different viruses, clinical trials outcomes, and mechanisms of antiviral action from the literature in order to highlight the therapeutic potential for the treatment of COVID-19. Furthermore, in preliminary PK/PD analyses using clinical data reported in the literature, comparison of simulated TIZ (active metabolite of NTZ) exposures at two doses with the in vitro potency of NTZ against SARS-CoV-2 gives further support for drug repurposing with potential in combination chemotherapy approaches. The review concludes with details of second generation thiazolides under development that could lead to improved antiviral therapies for future indications.

Tizoxanide induces autophagy by inhibiting PI3K/Akt/mTOR pathway in RAW264.7 macrophage cells.

As the main metabolite of nitazoxanide, tizoxanide (TIZ) has a broad-spectrum anti-infective effect against parasites, bacteria, and virus. In this study, we investigated the effects of TIZ on autophagy by regulating the PI3K/Akt/mTOR signaling pathway. RAW264.7 macrophage cells were treated with various TIZ concentrations. Cell viability assay, transmission electron microscope, and immunofluorescence staining were used to detect the biological function of the macrophage cells, and the expression levels of the autophagy pathway-related proteins were measured by Western blot. Results revealed that TIZ promoted the conversion of LC3-I to LC3-II, the formation of autophagy vacuoles, and the degradation of SQSTM1/p62 in a concentration- and time-dependent manner in RAW264.7 cells. Treatment with TIZ increased the Beclin-1 expression level and inhibited PI3K, Akt, mTOR, and ULK1 activation. These effects were enhanced by pretreatment with rapamycin but attenuated by pretreatment with LY294002. In addition, the conversion of LC3-I to LC3-II was observed in Vero, 293T, and HepG2 cells treated with TIZ. These data suggested that TIZ may induce autophagy by inhibiting the Akt/mTOR/ULK1 signaling pathway in macrophages and other cells.

Treatment of Helicobacter pylori with nitazoxanide-containing regimens: a systematic review.

Background:Helicobacter pylori is one of the most common chronic infections and is a leading cause of gastric cancer. There are currently several short-course treatment options available for the treatment of H. pylori. However, there has been a significant increase in global resistance patterns for H. pylori and there is a need for alternative treatment regimens. Nitazoxanide (NTZ) is an anti-protozoal agent that has been evaluated within several studies for the treatment of H. pylori. The objective of this review is to evaluate the efficacy and safety of NTZ-based treatments for a H. pylori infection.Methods: Pubmed (1946-August 2019) and Embase (1947-August 2019) were queried using the following search terms: Helicobacter, Helicobacter infection, Helicobacter pylori, nitazoxanide, tizoxanide, thiazoles, thiazole derivative and NTZ. Appropriate studies were evaluated with varying treatment regimens and cure rates.Results: Ten studies that utilized a NTZ-based treatment for H. pylori were identified from the literature search. Eight of the ten studies demonstrated a cure rate of greater than 80% in at least one NTZ-based treatment arm. Gastrointestinal side effects were the most commonly reported adverse drug reaction in the studies.Conclusions: Nitazoxanide-based treatments appear to be an effective treatment for H. pylori. While the ideal NTZ combination therapy is uncertain, a combination with a proton-pump inhibitor and one to two antibiotics has demonstrated the highest rates of H. pylori eradication. Nitazoxanide-based treatments are well-tolerated and minimal discontinuation due to side effects were reported in the studies.

Analysis of tizoxanide, active metabolite of nitazoxanide, in rat brain tissue and plasma by UHPLC-MS/MS.

Tizoxanide, the active metabolite of nitazoxanide, has recently been reported as an effective agent for the treatment of glioma. As there had been no report about the analysis of tizoxanide in brain tissue, we established extraction and UHPLC-MS/MS methods to quantify tizoxanide in rat brain and plasma to evaluate the brain-to-plasma ratio of tizoxanide. The biological samples were mainly prepared by acetonitrile and the separation was performed on a Waters XBridge® BEH C18 column. The mobile phase was composed of water mixed with 10 mm ammonium formate (pH 3.0) and acetonitrile according a gradient volume. Tizoxanide and topiramate (internal standard) were monitored utilizing negative electron spray ionization in multiple reaction monitoring mode. The methods were validated to be precise and accurate within the dynamic range of 5-1000 ng/mL and 0.2-50 ng/g for plasma and brain tissue samples, respectively. The lower limit of quantitation of the method was 0.2 ng/g, which was far more sensitive than all existing methods to quantify tizoxanide in biological samples. Application performed on rats exhibited that the brain-to-plasma ratio of tizoxanide ranged from 3.16 to 26.86% in 1 h after administration of 10 mg/kg nitazoxanide.

Tizoxanide Inhibits Inflammation in LPS-Activated RAW264.7 Macrophages via the Suppression of NF-κB and MAPK Activation.

Tizoxanide is the main active metabolite of nitazoxanide. Nitazoxanide and tizoxanide have a broad-spectrum anti-infective effect, including parasites, bacteria, and virus. In the present study, we investigated the anti-inflammatory effect of tizoxanide on lipopolysaccharide (LPS)-stimulated RAW264.7 cells and revealed underlying molecular mechanisms. The results showed that tizoxanide significantly suppressed production of NO as well as pro-inflammatory cytokines, such as IL-1ß, IL-6, and TNF-α in dose-dependent manner. Meanwhile, the levels of gene expression of these cytokines were inhibited significantly by tizoxanide that was discovered using RT-PCR. The increased protein levels of inducible nitric oxide synthase, heme oxygenase-1, and cyclooxygenase-2 by LPS in the cells were also reduced by tizoxanide. Moreover, we found that tizoxanide inhibited the phosphorylation of IKK-α and degradation of IκB by LPS in macrophage cells. The increased protein levels of p65 induced by LPS in the cytoplasm and nucleus were both decreased by tizoxanide, and the nuclear translocation of p65 was also restrained in cell imaging. In addition, tizoxanide considerably also inhibited LPS-activated JNK, p38, and ERK phosphorylation in RAW264.7 cells. Taken together, our results suggested that tizoxanide exerts anti-inflammatory effects, by inhibiting the production of pro-inflammatory cytokines and suppressing of the activation of the NF-κB and the MAPK signaling pathways in LPS-treated macrophage cells.