In Vitro and in Vivo Effects of Nitrofurantoin on Experimental Toxoplasmosis

The Brazilian Toxoplasma gondii strain BRI caused greater inflammation and impairment in anxiogenic behavior in mice, which was reverted by rosuvastatin treatment

This study aimed to investigate the effect of rosuvastatin treatment on anxiety-related behavior and short- and long-term memory impairment in mice infected with acute RH and BRI strains of Toxoplasma gondii. Balb/C mice were infected intraperitoneally and after 2 h, oral treatment with rosuvastatin (40 mg/kg/day) was initiated for 4 days. Behaviors related to anxiety and locomotion were evaluated in the open field (OF), and short- and long-term memory through the novel object recognition test (NOR). At the end of the experiments, peritoneal fluid, brain, liver, and lung were collected for T. gondii DNA quantification and histopathological analysis. Infection with BRI strain reduced the dwell time and central locomotion in the OF (p < 0.05), indicating anxiogenic type behavior, while treatment with rosuvastatin reversed this response (p < 0.05). RH strain infection did not alter any behavior in the OF (p > 0.05) and both strains impaired short- and long-term memory (NOR test), but with no significant treatment effect (p > 0.05). The BRI strain was shown to be more damaging in relation to anxiogenic type behavior when compared to the RH strain (p < 0.05), whereas rosuvastatin reduced this damaging effect in BRI. The treatment reduced the parasite load in the peritoneal lavage, liver, and lung of animals infected with both acute strains; however, it significantly (p < 0.05) attenuated the inflammatory process only in BRI-infected and treated animals, showing that non-archetypal genotypes are more damaging in rodents. This suggests that rosuvastatin may be a drug with great therapeutic potential against T. gondii mainly to reduce damage from virulent strains.

Evaluation of mono and combined nitrofurantoin therapy for toxoplasmosis in vivo using murine model

Toxoplasmosis is a frequent disease with an estimated prevalence of more than one billion human cases worldwide and over one million new infections each year. It is classified as a neglected tropical disease by the CDC since 2019. The disease may pass unnoticed in healthy individuals but could be fatal in the immunocompromised. Moreover, no effective treatment is available against the chronic form of the disease. Available anti-Toxoplasma drugs are associated with many side effects. Therefore, search for new more reliable, more efficient, and less toxic therapeutic agents is a continuous endeavor. This study assesses the potential use of nitrofurantoin, a compound with well-established antimicrobial properties, as a potential anti-Toxoplasma drug in vivo. It compares its efficacy to the commonly used anti-Toxoplasma agent spiramycin by molecular and histopathological methods in acute and chronic infection. The results demonstrate a significant ability to eliminate the parasite (P < 0.001) whether used as mono- or combined therapy with spiramycin in the acute and chronic stages. When compared to the anti-Toxoplasma drug spiramycin, nitrofurantoin achieved similar efficacy in the acute and chronic infection (P = 0.65 and P = 0.096, respectively). However, better results were obtained when using a combination of both drugs (P < 0.001). Additionally, nitrofurantoin showed good inhibitory effects on the inflammatory process in the liver, kidney, and uterus of the experimentally infected animals. In conclusion, nitrofurantoin can be considered as a potential anti-Toxoplasma agent. Nevertheless, further studies are recommended before consideration for clinical trials.

Inclusion of Nitrofurantoin into the Realm of Cancer Chemotherapy via Biology-Oriented Synthesis and Drug Repurposing

Structural modifications of the antibacterial drug nitrofurantoin were envisioned, employing drug repurposing and biology-oriented drug synthesis, to serve as possible anticancer agents. Eleven compounds showed superior safety in non-cancerous human cells. Their antitumor efficacy was assessed on colorectal, breast, cervical, and liver cancer cells. Three compounds induced oxidative DNA damage in cancer cells with subsequent cellular apoptosis. They also upregulated the expression of Bax while downregulated that of Bcl-2 along with activating caspase 3/7. The DNA damage induced by these compounds, demonstrated by pATM nuclear shuttling, was comparable in both MCF7 and MDA-MB-231 (p53 mutant) cell lines. Mechanistic studies confirmed the dependence of these compounds on p53-mediated pathways as they suppressed the p53-MDM2 interaction. Indeed, exposure of radiosensitive prostatic cancer cells to low non-cytotoxic concentrations of compound 1 enhanced the cytotoxic response to radiation indicating a possible synergistic effect. In vivo antitumor activity was verified in an MCF7-xenograft animal model.

Recent Advances in the Synthesis and Development of Nitroaromatics as Anti-Infective Drugs

Infectious diseases commonly occur in tropical and sub-tropical countries. The pathogens of such diseases are able to multiply in human hosts, warranting their continual survival. Infections that are commonplace include malaria, chagas, trypanosomiasis, giardiasis, amoebiasis, toxoplasmosis and leishmaniasis. Malaria is known to cause symptoms, such as high fever, chills, nausea and vomiting, whereas chagas disease causes enlarged lymph glands, muscle pain, swelling and chest pain. People suffering from African trypanosomiasis may experience severe headaches, irritability, extreme fatigue and swollen lymph nodes. As an infectious disease progresses, the human host may also experience personality changes and neurologic problems. If left untreated, most of these diseases can lead to death. Parasites, microbes and bacteria are increasingly adapting and generating strains that are resistant to current clinical drugs. Drug resistance creates an urgency for the development of new drugs to treat these infections. Nitro containing drugs, such as chloramphenicol, metronidazole, tinidazole and secnidazole had been banned for use as antiparasitic agents due to their toxicity. However, recent discoveries of nitrocontaining anti-tuberculosis drugs, i.e. delamanid and pretonamid, and the repurposing of flexinidazole for use in combination with eflornithine for the treatment of human trypanosomiasis, have ignited interest in nitroaromatic scaffolds as viable sources of potential anti-infective agents. This review highlights the differences between old and new nitration methodologies. It furthermore offers insights into recent advances in the development of nitroaromatics as anti-infective drugs.

Safety and efficacy of the bumped kinase inhibitor BKI-1553 in pregnant sheep experimentally infected with Neospora caninum tachyzoites

Neospora caninum is one of the main causes of abortion in cattle, and recent studies have highlighted its relevance as an abortifacient in small ruminants. Vaccines or drugs for the control of neosporosis are lacking. Bumped kinase inhibitors (BKIs), which are ATP-competitive inhibitors of calcium dependent protein kinase 1 (CDPK1), were shown to be highly efficacious against several apicomplexan parasites in vitro and in laboratory animal models. We here present the pharmacokinetics, safety and efficacy of BKI-1553 in pregnant ewes and foetuses using a pregnant sheep model of N. caninum infection. BKI-1553 showed exposure in pregnant ewes with trough concentrations of approximately 4 μM, and of 1  μM in foetuses. Subcutaneous BKI-1553 administration increased rectal temperatures shortly after treatment, and resulted in dermal nodules triggering a slight monocytosis after repeated doses at short intervals. BKI-1553 treatment decreased fever in infected pregnant ewes already after two applications, resulted in a 37–50% reduction in foetal mortality, and modulated immune responses; IFNγ levels were increased early after infection and IgG levels were reduced subsequently. N. caninum was abundantly found in placental tissues; however, parasite detection in foetal brain tissue decreased from 94% in the infected/untreated group to 69–71% in the treated groups. In summary, BKI-1553 confers partial protection against abortion in a ruminant experimental model of N. caninum infection during pregnancy. In addition, reduced parasite detection, parasite load and lesions in foetal brains were observed.

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BKI-1553 showed excellent exposure in pregnant ewes and foetuses.

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BKI-1553 confers partial protection against abortion in N. caninum infected ewes.

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Treatment reduces parasite detection, parasite load and lesions in foetal brains.

A Systematic Review of In vitro and In vivo Activities of Anti-Toxoplasma Drugs and Compounds (2006-2016)

The currently available anti-Toxoplasma agents have serious limitations. This systematic review was performed to evaluate drugs and new compounds used for the treatment of toxoplasmosis. Data was systematically collected from published papers on the efficacy of drugs/compounds used against Toxoplasma gondii (T. gondii) globally during 2006-2016. The searched databases were PubMed, Google Scholar, Science Direct, ISI Web of Science, EBSCO, and Scopus. One hundred and eighteen papers were eligible for inclusion in this systematic review, which were both in vitro and in vivo studies. Within this review, 80 clinically available drugs and a large number of new compounds with more than 39 mechanisms of action were evaluated. Interestingly, many of the drugs/compounds evaluated against T. gondii act on the apicoplast. Therefore, the apicoplast represents as a potential drug target for new chemotherapy. Based on the current findings, 49 drugs/compounds demonstrated in vitro half-maximal inhibitory concentration (IC50) values of below 1 μM, but most of them were not evaluated further for in vivo effectiveness. However, the derivatives of the ciprofloxacin, endochin-like quinolones and 1-[4-(4-nitrophenoxy) phenyl] propane-1-one (NPPP) were significantly active against T. gondii tachyzoites both in vitro and in vivo. Thus, these compounds are promising candidates for future studies. Also, compound 32 (T. gondii calcium-dependent protein kinase 1 inhibitor), endochin-like quinolones, miltefosine, rolipram abolish, and guanabenz can be repurposed into an effective anti-parasitic with a unique ability to reduce brain tissue cysts (88.7, 88, 78, 74, and 69%, respectively). Additionally, no promising drugs are available for congenital toxoplasmosis. In conclusion, as current chemotherapy against toxoplasmosis is still not satisfactory, development of well-tolerated and safe specific immunoprophylaxis in relaxing the need of dependence on chemotherapeutics is a highly valuable goal for global disease control. However, with the increasing number of high-risk individuals, and absence of a proper vaccine, continued efforts are necessary for the development of novel treatment options against T. gondii. Some of the novel compounds reviewed here may represent good starting points for the discovery of effective new drugs. In further, bioinformatic and in silico studies are needed in order to identify new potential toxoplasmicidal drugs.

Lectins from Synadenium carinatum (ScLL) and Artocarpus heterophyllus (ArtinM) Are Able to Induce Beneficial Immunomodulatory Effects in a Murine Model for Treatment of Toxoplasma gondii Infection

Infection by Toxoplasma gondii affects around one-third of world population and the treatment for patients presenting toxoplasmosis clinically manifested disease is mainly based by a combination of sulfadiazine, pyrimethamine, and folinic acid. However, this therapeutic protocol is significantly toxic, causing relevant dose-related bone marrow damage. Thus, it is necessary to improve new approaches to investigate the usefulness of more effective and non-toxic agents for treatment of patients with toxoplasmosis. It has been described that lectins from plants can control parasite infections, when used as immunological adjuvants in vaccination procedures. This type of lectins, such as ArtinM and ScLL is able to induce immunostimulatory activities, including efficient immune response against parasites. The present study aimed to evaluate the potential immunostimulatory effect of ScLL and ArtinM for treatment of T. gondii infection during acute phase, considering that there is no study in the literature accomplishing this issue. For this purpose, bone marrow-derived macrophages (BMDMs) were treated with different concentrations from each lectin to determine the maximum concentration without or with lowest cytotoxic effect. After, it was also measured the cytokine levels produced by these cells when stimulated by the selected concentrations of lectins. We found that ScLL showed high capacity to induce of pro-inflammatory cytokine production, while ArtinM was able to induce especially an anti-inflammatory cytokines production. Furthermore, both lectins were able to increase NO levels. Next, we evaluated the treatment effect of ScLL and ArtinM in C57BL/6 mice infected by ME49 strain from T. gondii. The animals were infected and treated with ScLL, ArtinM, ArtinM plus ScLL, or sulfadiazine, and the following parameters analyzed: Cytokines production, brain parasite burden and survival rates. Our results demonstrated that the ScLL or ScLL plus ArtinM treatment induced production of pro-inflammatory and anti-inflammatory cytokines, showing differential but complementary profiles. Moreover, when compared with non-treated mice, the parasite burden was significantly lower and survival rates higher in mice treated with ScLL or ScLL plus ArtinM, similarly with sulfadiazine treatment. In conclusion, the results demonstrated the suitable potential immunotherapeutic effect of ScLL and ArtinM lectins to control acute toxoplasmosis in this experimental murine model.