Anti-Toxoplasma activity of various molecular weights and concentrations of chitosan nanoparticles on tachyzoites of RH strain

Evaluation of the Efficacy of Chitosan Nanoparticles based on Rosuvastatin in the Treatment of acute Toxoplasmosis : An In vitro and In vivo study

Toxoplasma gondii (T.gondii) is an obligate intracellular protozoan that infects warm-blooded animals and has a global distribution. Acute toxoplasmosis is commonly reported in patients with acquired/congenital toxoplasmosis and immune deficiency. New methods are needed to prevent the sideffects of classical treatment. In this study, Rosuvastatin loaded chitosan nanoparticle (CH-NP-ROS) were synthesized and zeta potencial and size were determined, and an MTT assay was performed to evaluate the cell toxicity on Macrophage cells (MQ) and anti-Toxoplasma activity using Trypan-blue staining by different concentrations of Rosuvastatin (ROS), and Rosuvastatin loaded chitosan nanoparticle (CH-NP-ROS). The cell viability assay demonstrated that CH-NP-ROS had lower cell toxicity (<15%) compared to ROS (<30%). Statistical analysis showed that CH-NP-ROS significantly killed 98.950 ± 1.344; P < 0.05) of Toxoplasma gondii tachyzoites. In vivo results of perituneal fluid showed that CH-NP significantly reduced the parasite load in the CH-NP-ROS group, compared to that in negative control group (P < 0.001). Growth inhibition rates of tachyzoites in mice receiving free ROS and CH-NP-ROS (injection and oral form) were found to be 166.125+4.066, 118.750+4.596 and 124.875+2.652, respectively, compared to mice in Sulfadiazine/Pyrimethamine treated group (positive control). In the infected untreated mice (control +), the mean tachyzoite counts per oil immersion field in the spleen was 8.25 respectively. The mean survival time in all the groups treated with ROS and CH-NP-ROS was longer than that in the negative control group Therefore, nanoformulation is a promising approach for the delivery and is safe for using therapeutic effects in acute toxoplasmosis.

Anti-Toxoplasma gondii activity of rose hip oil-solid lipid nanoparticles

Toxoplasma gondii is a highly prevalent pathogen, reported from almost all geographical regions of the world. Current anti-T. gondii drugs are not effective enough in immunocompromised patients, encephalitis, chorioretinitis, and congenital toxoplasmosis. Therefore, the prescription of these drugs has been limited. Rose hip oil (RhO) is a natural plant compound, which shows antibacterial, anticancer, and anti-inflammatory activities. In the current study, the anti-T. gondii and cell toxicity effects of solid lipid nanoparticles (SLNs) loaded by RhO (RhO-SLNs) were evaluated. Emulsification sonicated-homogenization method was used to prepare SLNs. RhO-SLNs were characterized, and their anti-T. gondii and cell toxicity effects were evaluated using in vitro analyses. The particle size and the zeta potential of the nanoparticles were 152.09 nm and -15.3 mV nm, respectively. The entrapment efficiency percentage was 79.1%. In the present study, the inhibitory concentration (IC)50 against T. gondii was >1 μg/mL (p-value <.0001). The cell toxicity assay showed cytotoxicity concentration (CC)50 >10 mg/mL (p-value = .017). In addition, at least 75% of T. gondii-infected Vero cells remained alive at concentrations >10 mg/mL. The concentration of 1 mg/mL showed highest anti-Toxoplasma activity and lowest cell toxicity against the Vero cell. Our findings suggest that carrying natural plant compounds with SLNs could be considered an effective option for treatment strategies against T. gondii infections.

Cytotoxic and Immunomodulatory Activity of Curcumin and Chitosan on Experimental Toxoplasmosis

Background

Toxoplasma gondii is a pathogenic parasite with worldwide distribution. We investigated curcumin and chitosan in combination on the viability of T. gondii tachyzoites in silico, in vitro and in vivo.

Methods

A 3D model was employed in Urmia University of Medical Sciences, Urmia, Iran in 2021 to study the interaction between curcumin and dihydrofolate reductase (DHFR). Ramachandran root-mean-square deviation and VERIFY3D validated the model. Cytotoxicity of curcumin and chitosan was evaluated by MTT viability assay. BALB/c mice infected with 104 Toxoplasma organisms were treated with curcumin, chitosan, and the combination of curcumin+chitosan. Serum levels of inducible NO synthetase (iNOs), interferon gamma (IFN-γ), interleukin (IL)-5, glutamate oxaloacetic transaminases(SGOT), and glutamic pyruvate transaminase (SGPT) were determined.

Result

Curcumin-DHFR and curcumin-DHPS (dihydropteroate synthase) interactions and calculated enzyme energy indicated an excellent affinity for curcumin with DHFR, but not DHPS. MTT results of concurrent treatments demonstrated IC50 rates of 0.1, 0.05, and 0.01 mg/ml at 24, 48, and 72h, respectively. IFN-γ, IL-5 and iNOs levels in curcumin+chitosan treated mice were 1.71, 0.51, and 1.51 IU/L, while those of SGOT and SGPT were 76 and 84 IU/L, respectively.

Conclusion

The combination of curcumin and chitosan increased survival time of infected mice by seven days. Curcumin and chitosan in combination regulated the immune system and reduced liver damage, potentially forming the basis of a new treatment for toxoplasmosis.

Formulation and evaluation of atovaquone-loaded macrophage-derived exosomes against Toxoplasma gondii: in vitro and in vivo assessment

IMPORTANCE

This study is the first of its kind that suggests exosomes as a nano-carrier loaded with atovaquone (ATQ), which could be considered as a new strategy for improving the effectiveness of ATQ against acute and chronic phases of Toxoplasma gondii.

Development of solid lipid nanoparticles-loaded drugs in parasitic diseases

Parasites cause illnesses with broad spectrum of symptoms from mild to severe, and are responsible for a significant number of outbreaks in the world. Current anti-parasitic drugs are toxic and have significant side effects. Nano-carriers are believed to obviate the limitations of conventional drugs via decreasing side effects and increasing target delivery and drug permeability with a controlled prolonged release of a drug. Solid lipid nanoparticles (SLNs) are lipid nanoparticles (LNPs), which have frequently been practiced. Suitable release rate, stability, and target delivery make SLNs a good alternative for colloidal carriers. SLNs are supposed to have great potential to deliver natural products with anti-parasitic properties. Nanoparticles have employed to improve stability and capacity loading of SLNs, during recent years. This review describes development of SLNs, the methods of preparation, characterization, and loaded drugs into SLNs in parasitic diseases. In addition, we summarize recent development in anti-parasitic SLNs-loaded drugs.

The Therapeutic Efficacy of Zinc Oxide Nanoparticles on Acute Toxoplasmosis in BALB/c Mice

Background

Toxoplasma gondii infects nearly one-third of the world's population. Due to the significant side effects of current treatment options, identifying safe and effective therapies seems crucial. Nanoparticles (NPs) are new promising compounds in treating pathogenic organisms. Currently, no research has investigated the effects of zinc oxide NPs (ZnO-NPs) on Toxoplasma parasite. We aimed to investigate the therapeutic efficacy of ZnO-NPs against tachyzoite forms of T. gondii, RH strain in BALB/c mice.

Methods

In an experiment with 35 female BALB/c mice infected with T. gondii tachyzoites, colloidal ZnO-NPs at concentrations of 10, 20, and 50 ppm, as well as a 50 ppm ZnO solution and a control group, were orally administered four hours after inoculation and continued daily until the mices' death. Survival rates were calculated and tachyzoite counts were evaluated in the peritoneal fluids of infected mice.

Results

The administration of ZnO-NPs resulted in the reduction of tachyzoite counts in infected mice compared to both the ZnO-treated and control group (P<0.001). Intervention with ZnO-NPs significantly increased the survival time compared to the control group (6.2±0.28 days, P-value <0.05), additionally, the highest dose of ZnO-NPs (50 ppm) showed the highest mice survival time (8.7±0.42 days).

Conclusion

ZnO-NPs were effective in decreasing the number of tachyzoites and increasing mice survival time in vivo. Moreover, there were no significant differences in survival time between the untreated control group and the group treated with zinc oxide, suggesting that, bulk ZnO is not significantly effective in comparison with ZnONPs.

Nanoformulation-Based 1,2,3-Triazole Sulfonamides for Anti-Toxoplasma In Vitro Study

Toxoplasma gondii is deemed a successful parasite worldwide with a wide range of hosts. Currently, a combination of pyrimethamine and sulfadiazine serves as the first-line treatment; however, these drugs have serious adverse effects. Therefore, it is imperative to focus on new therapies that produce the desired effect with the lowest possible dose. The designation and synthesis of sulfonamide-1,2,3-triazole hybrids (3a-c) were performed to create hybrid frameworks. The newly synthesized compounds were loaded on chitosan nanoparticles (CNPs) to form nanoformulations (3a.CNP, 3b.CNP, 3c.CNP) for further in vitro investigation as an anti-Toxoplasma treatment. The current study demonstrated that all examined compounds were active against T. gondii in vitro relative to the control drug, sulfadiazine. 3c.CNP showed the best impact against T. gondii with the lowest IC50 value of 3.64 µg/mL. Using light microscopy, it was found that Vero cells treated with the three nanoformulae showed remarkable morphological improvement, and tachyzoites were rarely seen in the treated cells. Moreover, scanning and transmission electron microscopic studies confirmed the efficacy of the prepared nanoformulae on the parasites. All of them caused parasite ultrastructural damage and altered morphology, suggesting a cytopathic effect and hence confirming their promising anti-Toxoplasma activity.

Synthesis, characterization, and antiparasitic effects of zinc oxide nanoparticles-eugenol nanosuspension against Toxoplasma gondii infection

Background

In this study, zinc oxide nanoparticles-coated with eugenol (ZnO@Eug) were synthesized and evaluated as a nanosuspension (NSus) formulation against Toxoplasma gondii in vitro and in vivo.

Methods

An anti-Toxoplasma activity assay for ZnO@Eug NSus was conducted in vitro, ex vivo, and in vivo. FTIR spectroscopy confirmed the formation of ZnO@Eug NSus by detecting several functional groups involved; EDX and SEM demonstrated the grain of ZnO-NPs embedded with Eug and compositional purity.

Results

Surface charge (ZP) and size distribution (DLS) of ZnO@Eug NSus were determined to be -22.7 mV and 109.6 nm, respectively. According to the release kinetics, approximately 60% of the ZnO-NPs and Eug were released in the first 45 min. In the cytotoxicity assay, ZnO-NPs, Eug, and ZnO@Eug NSus had IC50 values of 71.85, 22.39, and 2.02 mg/mL, respectively. The therapeutic efficacy of ZnO@Eug against T. gondii was 56.3%, which was not significantly different from that of spiramycin (58.9%) (Positive-control). The tissue tachyzoites in the liver, spleen, and peritoneum were less than 50% in groups treated with Eug, spiramycin, and ZnO@Eug NSus compared to the control. ZnO@Eug-treated groups showed a survival rate of up to 13 days.

Conclusions

The ZnO@Eug NSus demonstrated antiparasitic activity against T. gondii with minimal toxic effects and high efficiency in increasing the survival of infected mice. The nanoformulations of ZnO-NPs incorporated with Eug could, in the future, be considered for treating toxoplasmosis in humans and animals if a detailed study was conducted to determine the precise dose and measure side effects.

Nanoemulsion of Spiramycin against Tachyzoites of Toxoplasma gondii, RH Strain: Preparation, Toxicology, and Efficacy Studies

Background

Toxoplasma infection is caused by Toxoplasma gondii, which is an intracellular protozoan parasite. This infection consequently lead various congenital disabilities during pregnancy in patients. Spiramycin (Spi), a macrolide antibiotic, is typically recommended for T. gondii infection in pregnant women. We aimed to prepare the nanoemulsion of spiramycin (NE-Spi) and to evaluate the activity of this formulation in tachyzoites of T. gondii, RH strain.

Methods

This study was conducted in 2019-2021 at the School of Public Health, Tehran University of Medical Sciences, Tehran, Iran. NE-Spi was prepared by spontaneous emulsification. The effects of this nanoemulsion on the viability of cultured cells were measured using MTT assay. To estimate the effects of NE-Spi on tachyzoites of T. gondii, RH strain, different concentrations of NE-Spi, S-Spi (suspension of spiramycin), and NE (nanoemulsion without any spiramycin) were added to tachyzoites and then stored for 30, 60, 90, 120 min and 24 h in 250 µg/ml concentration at room temperature. Finally, Tachyzoites mortality rates were evaluated by trypan blue staining. Of note, flow cytometry was conducted to confirm the obtained results.

Results

The final particle size of NE-Spi was calculated to be 11.3 nm by DLS and TEM. Thereafter, using MTT assay, in 62.5 µg/ml concentration of NE-Spi, the Vero cells viability was obtained as 82%. The highest mortality rates of tachyzoites of T.gondii, RH strain were observed at 250 µg/ml concentration and after 120 min of exposure, but it was not significantly different from 24 h of exposure.

Conclusion

NE-Spi has lethal efficacy on T. gondii RH strain in-vitro.

Hassan A, Mohamed K, Alfaifi MS, Elshazly H, Alamri ZZ, Wakid MH, Gattan HS, Altwaim SA, Al-Megrin WAI, Younis S. Zinc oxide nanoparticles produced by Zingiber officinale ameliorates acute toxoplasmosis-induced pathological and biochemical alterations and reduced parasite burden in mice model

BACKGROUND

Although, approximately 30% of the world's population is estimated to be infected with Toxoplasma gondii (T. gondii) with serious manifestations in immunocompromised patients and pregnant females, the available treatment options for toxoplasmosis are limited with serious side effects. Therefore, it is of great importance to identify novel potent, well tolerated candidates for treatment of toxoplasmosis. The present study aimed to evaluate the effect of Zinc oxide nanoparticles (ZnO NPs) synthesized using Zingiber officinale against acute toxoplasmosis in experimentally infected mice.

METHODS

The ethanolic extract of ginger was used to prepare ZnO NPs. The produced ZnO NPs were characterized in terms of structure and morphology using Fourier Transformed Infrared Spectroscopy (FTIR), X-Ray Diffraction (XRD), UV- spectroscopy and scanning electron microscopy (SEM). The prepared formula was used in treatment of T. gondii RH virulent strain. Forty animals were divided into four groups, with ten mice per group. The first group was the uninfected, control group. The second group was infected but untreated. The third and the fourth groups received ZnO NPs and Spiramycin orally in a dose of 10 mg/kg and 200 mg/kg/day respectively. The effect of the used formulas on the animals survival rate, parasite burden, liver enzymes -including Alanine transaminase (ALT) and aspartate transaminase (AST)-, nitric oxide (NO) and Catalase antioxidant enzyme (CAT) activity was measured. Moreover, the effect of treatment on histopathological alterations associated with toxoplasmosis was examined.

RESULTS

Mice treated with ZnO NPs showed the longest survival time with significant reduction in the parasite load in the livers and peritoneal fluids of the same group. Moreover, ZnO NPs treatment was associated with a significant reduction in the level of liver enzymes (ALT, AST) and NO and a significant increase in the antioxidant activity of CAT enzyme. SEM examination of tachyzoites from the peritoneal fluid showed marked distortion of T. gondii tachyzoites isolated from mice treated with ZnO NPs in comparison to untreated group. T. gondii induced histopathological alterations in the liver and brain were reversed by ZnO NPs treatment with restoration of normal tissue morphology.

CONCLUSION

The produced formula showed a good therapeutic potential in treatment of murine toxoplasmosis as demonstrated by prolonged survival rate, reduced parasite burden, improved T. gondii associated liver injury and histopathological alterations. Thus, we assume that the protective effect observed in the current research is attributed to the antioxidant capability of NPs. Based on the results obtained from the current work, we suggest greenly produced ZnO NPs as a chemotherapeutic agent with good therapeutic potential and high levels of safety in the treatment of toxoplasmosis.

Metallic Nanoparticles and Core-Shell Nanosystems in the Treatment, Diagnosis, and Prevention of Parasitic Diseases

The usage of nanotechnology in the fight against parasitic diseases is in the early stages of development, but it brings hopes that this new field will provide a solution to target the early stages of parasitosis, compensate for the lack of vaccines for most parasitic diseases, and also provide new treatment options for diseases in which parasites show increased resistance to current drugs. The huge physicochemical diversity of nanomaterials developed so far, mainly for antibacterial and anti-cancer therapies, requires additional studies to determine their antiparasitic potential. When designing metallic nanoparticles (MeNPs) and specific nanosystems, such as complexes of MeNPs, with the shell of attached drugs, several physicochemical properties need to be considered. The most important are: size, shape, surface charge, type of surfactants that control their dispersion, and shell molecules that should assure specific molecular interaction with targeted molecules of parasites' cells. Therefore, it can be expected that the development of antiparasitic drugs using strategies provided by nanotechnology and the use of nanomaterials for diagnostic purposes will soon provide new and effective methods of antiparasitic therapy and effective diagnostic tools that will improve the prevention and reduce the morbidity and mortality caused by these diseases.

The role of Curcuma longa essential oil in controlling acute toxoplasmosis by improving the immune system and reducing inflammation and oxidative stress

Background

Chemotherapy with synthetic drugs is the principal approach for toxoplasmosis treatment; however, recent studies reported the limitations and adverse side effects of these chemical drugs.

Objective

This study aimed to examine the in vitro and in vivo effects of Curcuma longa essential oil (CLE) against the Toxoplasma gondii RH strain.

Methods

The in vitro effect of different concentrations of CLE on T. gondii tachyzoites was assessed by cell viability assay. Flow cytometry and apoptosis analysis were performed, and nitric oxide production by CLE was also evaluated in tachyzoites. BALB/c mice were orally treated with various doses (1.25, 2.5, and 5 mg·kg^-1·day^-1) of CLE for 2 weeks. After the induction of acute toxoplasmosis in the mice, their survival rate and the mean number of peritoneal parasites were checked. The hepatic level of antioxidant enzymes and oxidative stress markers was evaluated by commercial kits. The mRNA expression level of proinflammatory cytokines such as interleukin 1-beta (IL-1β) and interferon-gamma (IFN-γ) was evaluated by quantitative real-time PCR.

Results

CLE, especially at 50 µg/ml, showed potent inhibitory effects on T. gondii tachyzoites. It increased the survival rate (ninth day) and reduced the mean number of peritoneal tachyzoites in the infected mice. CLE dependently increased (p < 0.01) the number of necrotic and apoptotic cells as well as NO production. CLE significantly (p < 0.05) reduced the hepatic level of oxidative stress markers but increased (p < 0.001) the antioxidant enzymes and proinflammatory cytokines in the infected mice, with no important toxicity for vital organs.

Conclusion

The findings of this survey revealed the significant in vitro inhibitory effects of CLE on T. gondii tachyzoites. The results also exhibited promising in vivo effects of CLE. CLE improved the survival rate of infected mice and reduced the parasite number in them. Although the mechanisms of action of CLE are not clear, our study demonstrated its beneficial effects on acute toxoplasmosis by strengthening the immune system and reducing inflammation and oxidative stress. Still, more studies are required to confirm these results.

Protoscolicidal effects of curcumin nanoemulsion against protoscoleces of Echinococcus granulosus

BACKGROUND

The aim of the present study was to assess in vitro protoscolicidal effects of curcumin nanoemulsion (CUR-NE) against protoscoleces of cystic echinococcosis (CE)/hydatid cysts.

METHODS

The CUR-NE was prepared via spontaneous emulsification of soybean as the oil phase, a mixture of Tween 80 and Tween 85 as the surfactant, ethanol as the co-surfactant and distilled water. Various concentrations of CUR-NE (156, 312, 625 and 1250 µg/ml) were exposed to collected protoscoleces of infected sheep liver hydatid cysts for 10, 20, 30, 60 and 120 min. Viability of the protoscoleces were assessed using eosin exclusion test. Morphological changes of the protoscoleces were observed using differential interference contrast (DIC) microscopy.

RESULTS

The mean particle size and zeta potential of CUR-NE included 60.4 ± 14.8 nm and - 16.1 ± 1.1 mV, respectively. Results showed that the viability of the protoscoleces decreased significantly with increases in CUR-NE concentrations (p < 0.001). The mortality rates of protoscoleces with exposure to concentrations of 1250 and 625 µg/ml of CUR-NE for 60 min were 94 and 73.33%, respectively. Mortality of the protoscoleces was 100% after 120 min of exposure to 1250 and 625 µg/ml concentrations of CUR-NE. Using NIC microscopy, extensively altered tegumental surface protoscoleces was observed after protoscoleces exposure to CUR-NE.

CONCLUSION

The findings of the present study revealed the in vitro protoscolicidal potential of CUR-NE. Therefore, CUR-NEs are addressed as novel protoscolicidal agents, which can be used as an alternative natural medicine to kill the protoscoleces, owing to their low toxicity and significant inhibition potency. However, further studies are necessary to investigate pharmacologic and pharmacokinetics of CUR-NEs.

Genetic Diversity of Toxoplasma gondii by Serological and Molecular Analyzes in Different Sheep and Goat Tissues in Northeastern Iran

Background

Toxoplasmosis is a parasitic disease caused by compilation protozoan agent Toxoplasma gondii, leading to significant financial and quality-adjusted life-year losses. Overcooked or raw meat consumption has been a considerable transmission route. The present study was conducted to determine the seropositivity rate of T. gondii in sheep and goats by serological and molecular tests and genotyping of obtained isolates in northeast Iran.

Methods

Blood and tissue samples (diaphragm, heart) of 296 animals (including 168 sheep and 128 goats) were collected from the slaughterhouse in Quchan Country from august 2016 to April 2017. Modified agglutination test (MAT) and the PCR method performed to detect parasite DNA on tissues.PCR-RFLP method of GRA6 gene was used to determine the genotype of T. gondii. In addition, sequencing analysis was performed to evaluate the Toxoplasma type strains.

Results

Serum positive for MAT results were found in 27.4% of sheep and 23.4% of goats. Positive PCR of B1 gene results in diaphragm and heart tissues of sheep and goats was 47.8% and 26.1%, 40% and 23.3%, respectively. PCR of GRA6 gene results were positive in 10 samples that RFLP technique results using MseI enzyme revealed genotype I. Sequencing and phylogenetic analysis revealed DNA of all samples was closely related to Toxoplasma type I.

Conclusion

Concerning the high seropositivity rate of toxoplasmosis, undertaking an appropriate preventive program for reducing the prevalence of T. gondii infection by raw or undercooked meat consumption of livestock is recommended. Our study supports the notion that these animals' consumption of raw and undercooked meat can be a probable source of human toxoplasmosis.

The synergetic potential of Lactobacillus delbrueckii and Lactobacillus fermentum probiotics in alleviating the outcome of acute toxoplasmosis in mice

Toxoplasmosis is an immunologically complex disease, particularly in immunocompromised patients. Although there are several therapeutic regimens for such disease, the majority of them have many drawbacks. Therefore, it is of utmost importance to improve the current regimen in an effort to achieve a well-tolerated therapy while also enhancing the host immune response. Famous for their immunomodulatory effect, Lactobacillus delbrueckii and Lactobacillus fermentum probiotics were chosen to be evaluated in this study as an adjuvant therapy against the virulent RH Toxoplasma gondii (T. gondii) strain. Experimental mice were divided into control and treated groups. The control group was further subdivided into two groups: group I: 10 uninfected mice and group II: 20 infected untreated mice. The treated experimental group was subdivided into three groups (20 mice each); group III: sulfamethoxazole-trimethoprim (SMZ-TMP) treated, group IV: probiotics treated, and group V: SMZ-TMP combined with probiotics. The results obtained revealed that combined therapy increased survival rate and time up to 95% and 16 days, respectively, with an 82% reduction of tachyzoites and marked distortion, as detected by the scanning electron microscope (SEM). Additionally, combined therapy alleviated the severity and the extent of the inflammatory cells' infiltration, thereby reducing hepatocyte degeneration. Intriguingly, serum IF-γ level showed a significant increase to 155.92 ± 10.12 ng/L with combined therapy, reflecting the immunological role of the combined therapy. The current results revealed that probiotics have a high adjuvant potential in alleviating the impact of toxoplasmosis. Using probiotics as a synergistic treatment to modulate conventional therapy in systemic toxoplasmosis may gain popularity due to their low cost and current availability.

In Vitro Study to Evaluate the Efficacy of Ultrasonicated Ethanolic Extract of Rosmarinus officinalis and its Chitosan-Based Nanoparticles Against Eimeria tenella Oocysts of Chickens

In this study, chitosan nanoparticles (CsNPs) were used as nanocarrier for ultrasonicated ethanolic extract of Rosmarinus officinalis (UEERO) as a new nanoformulation against Eimeria tenella. Herein, CsNPs have been synthesized by ionic gelation method at pH 3 (CsNPs3) and pH 5 (CsNPs5), followed by characterization of morphology, size, polydispersity index (PDI), surface charge, and loading efficiency of UEERO. An in vitro sporulation inhibition assay (10, 5, 2.5, 1.25, 0.62, 0.31, 0.15, 0.07, 0.04, 0.02, and 0.01 mg/ml normal saline solution) against E. tenella was conducted. Results showed that free CsNPs and UEERO-CsNPs3/5 were cubic- and spherical-shaped with positive charge and average size of ~ 150.8 nm (314.4 nm) and 151.7 nm (321.1 nm), respectively. The total loading efficiency using UV–vis spectrophotometer, was 80.05 at pH 5 and 64.39% at pH 3. The in vitro sporulation inhibition assay revealed that UEERO, CsNPs3/5, and UEERO-CsNPs3/5 showed a potential inhibitory effect on sporulation (%), distortion in wall (%), and sporocyst abnormality (%) in a dose-dependent manner. Accordingly, the concentration (10 mg/ml) showed the best efficacy after 24 h in UEERO, free CsNPs, and UEERO-CsNPs. Moreover, UEERO-CsNPs3 and UEERO-CsNPs5 had stopped the sporulation (%) after 72 h. Taken all together, UEERO-CsNPs3 and UEERO-CsNPs5 are best effective against E. tenella in a dose-dependent manner in terms of sporulation (%), distortion in wall (%), and sporocysts abnormality.

Evaluation of anti-parasitic activities of new quinolones containing nitrofuran moiety against Toxoplasma gondii

Toxoplasmosis is a disease with a worldwide prevalence that is caused by Toxoplasma gondii. Pyrimethamine and sulfadiazine are two pharmacological agents commonly used to treat of this infection. However, they are accompanied by some side effects. Therefore, the identifying of new drugs with low toxocytosis seems to be a matter of vital importance. Quinolones are DNA replication inhibitors, exerting inhibitory effects against many pathogens, including bacteria, mycoplasma, and protozoa. Given the importance of quinolones and their efficacy, the present in vitro study was conducted to investigate the antiparasitic activities of new quinolones (NFQ-2, NFQ-5, and NFQ-6) containing nitrofuran moiety against T. gondii. To this end, Vero cells were incubated with various concentrations of new quinolones and pyrimethamine (positive control) to determine their viability. Subsequently, they were infected with T. gondii (RH strain) and then subjected to drug treatment. The obtained IC₅₀ values were 3.60, 4.84, 5.59, 3.44 and 2.75 μg/mL for NFQ-2, NFQ-5, NFQ-6, ciprofloxacin and pyrimethamine, respectively. The CC₅₀ values for the NFQ-2, NFQ-5, and NFQ-6 were 25.20, 29.89, and 28.43 μg/mL, indicating the selectivity indexes more than 5 for these compounds. The anti-Toxoplasma efficiency was determined by evaluating infection index, number and size of plaques, and T. gondii intracellular proliferation. As the results indicated, the administration of new quinolone derivatives resulted in the reduction of intracellular proliferation, infection index, and the number and size of plaques in comparison to uninfected treated cells (P < 0.05). The results were indicative of a considerable synergetic effect when each of the derivatives was used in combination with pyrimethamine, compared to when used alone. Based on our results, the nitrofuran-derived quinolones can be considered as new leads for the design of new anti-Toxoplasma agents.

Novel naltrexone hydrochloride nanovaccine based on chitosan nanoparticles promotes induction of Th1 and Th17 immune responses resulting in protection against Toxoplasma gondii tachyzoites in a mouse model

This study was aimed to encapsulate and construct the Toxoplasma gondii surface antigen (SAG1) and naltrexone hydrochloride (NLT-HCL) as an adjuvant within chitosan nanoparticles (CS-NPs) to develop efficacious vaccine against T. gondii. Seven groups of BALB/c mice were immunized with SAG1, chitosan (CS), NLT-SAG1, CS-SAG1, CS-SAG1-NLT, CS-NLT and PBS. The efficiency of each approach was detected in vivo mouse immunization. Moreover, the immuno-induction effect of SAG1 recombinant protein and CS-NPs-based NLT-HCL as an adjuvant in a vaccine delivery was evaluated. Experimentally, Th1/Th17 biased cellular and humoral immune responses were activated in the mice immunized with CS-SAG1-NLT nanoparticles that were accompanied by considerable increased production of IFN-γ, IL-17, IL-12, IL-4, IFN-γ/IL-4 ratio, IgG, IgG2a. This group of mice also showed significantly increased survival time post-challenging. The successful encapsulated SAG1 recombinant protein and NLT-HCL, as an adjuvant, within CS-NPs can induce immune responses against toxoplasmosis. We could incorporate NLT-HCL adjuvant into the CS-NPs based delivery systems, which makes CS-NPs attractive as a colloidal carrier system for NLT-HCL as secondary adjuvant. This new approach or the simultaneous use of CS and NLT demonstrated that the co-administration of CS-NPs and NLT-HCL induce production of IL-17 cytokine. This approach can be used for vaccination purposes, in which Th17 and Th1 cellular immune are considered the key of the successful immune response.

Formulation of Neem oil-loaded solid lipid nanoparticles and evaluation of its anti-Toxoplasma activity

BACKGROUND

Toxoplasmosis is caused by an intracellular zoonotic protozoan, Toxoplasma gondii, which could be lethal in immunocompromised patients. This study aimed to synthesize Neem oil-loaded solid lipid nanoparticles (NeO-SLNs) and to evaluate the anti-Toxoplasma activity of this component.

METHODS

The NeO-SLNs were constructed using double emulsification method, and their shape and size distribution were evaluated using transmission electron microscope (TEM) and dynamic light scattering (DLS), respectively. An MTT assay was employed to evaluate the cell toxicity of the component. The anti-Toxoplasma activity of NeO-SLNs was investigated using vital (trypan-blue) staining. Anti-intracellular Toxoplasma activity of NeO-SLNs was evaluated in T. gondii-infected Vero cells.

RESULTS

The TEM analysis represented round shape NeO-SLNs with clear and stable margins. DLS analysis showed a mean particle size 337.6 nm for SLNs, and most of nanoparticles were in range 30 to 120 nm. The cell toxicity of NeO-SLNs was directly correlated with the concentration of the component (P-value = 0.0013). The concentration of NeO-SLNs, which was toxic for at least 50% of alive T. gondii (cytotoxic concentration (CC50)), was > 10 mg/mL. The ability of NeO-SLNs to kill Toxoplasma was concentration-dependent (P-value < 0.0001), and all concentrations killed at least 70% of alive tachyzoites. Furthermore, the viability of T. gondii- infected Vero cells was inversely correlated with NeO-SLNs concentrations (P-value = 0.0317), and in the concentration 100 μg/mL at least 75% of T. gondii- infected Vero cells remained alive.

CONCLUSIONS

Overall, our findings demonstrated that the NeO-SLNs was able to kill T. gondii tachyzoites in concentration 100 μg/mL with a cell toxicity lower than 20%. Such results suggest that employing SLNs as carrier for NeO can effectively kill T. gondii tachyzoites with acceptable cell toxicity. Our findings also showed that SLNs capsulation of the NeO can lead to prolonged release of the extract, suggesting that NeO-SLNs could be also employed to clear cyst stages, which should be further investigated in animal models.

Synthesis, Characterization and Nanoformulation of Novel Sulfonamide-1,2,3-triazole Molecular Conjugates as Potent Antiparasitic Agents

Toxoplasma gondii (T. gondii) is a highly prevalent parasite that has no gold standard treatment due to the poor action or the numerous side effects. Focused sulfonamide-1,2,3-triazole hybrids 3a–c were wisely designed and synthesized via copper catalyzed 1,3-dipolar cycloaddition approach between prop-2-yn-1-alcohol 1 and sulfa drug azides 2a–c. The newly synthesized click products were fully characterized using different spectroscopic experiments and were loaded onto chitosan nanoparticles to form novel nanoformulations for further anti-Toxoplasma investigation. The current study proved the anti-Toxoplasma effectiveness of all examined compounds in experimentally infected mice. Relative to sulfadiazine, the synthesized sulfonamide-1,2,3-triazole (3c) nanoformulae demonstrated the most promising result for toxoplasmosis treatment as it resulted in 100% survival, 100% parasite reduction along with the remarkable histopathological improvement in all the studied organs.

Remarkable histopathological improvement of experimental toxoplasmosis after receiving spiramycin-chitosan nanoparticles formulation

The present study investigated the anti-Toxoplasma effect of chitosan nanoparticles [CS NPs], spiramycin, spiramycin co-administered with metronidazole and spiramycin-CS NPs formulation on the parasite burden and histopathological changes in the liver, spleen and brain in experimentally infected mice. Seventy male Swiss albino mice were classified into seven equal groups: healthy control (I), infected untreated control (II), infected group receiving CS NPs (III), spiramycin administered infected group (IV), infected group receiving spiramycin-metronidazole (V), infected receiving 400 mg/kg spiramycin-CS NPs (VI) and infected treated with spiramycin-loaded CS NPs 100 mg/kg (VII). All groups were inoculated intraperitoneally with 2500 T. gondii tachyzoites RH strain except the healthy control group. All groups were sacrificed on the 8th day after infection. Density of the parasite and histopathological examination of the liver, spleen and brain of all treated mice revealed reduction in the mean tachyzoites count as well as decreased inflammation, congestion and necrosis within tissue sections. Spiramycin-loaded NPs displayed the highest significant reduction in the pathological insult tailed by spiramycin-metronidazole and CS NPs. In conclusion, spiramycin-loaded CS NPs showed a promising synergistic combination in the treatment of the histopathology caused by toxoplasmosis.

Chitosan Protects Immunosuppressed Mice Against Cryptosporidium parvum Infection Through TLR4/STAT1 Signaling Pathways and Gut Microbiota Modulation

Cryptosporidium parvum infection is very common in infants, immunocompromised patients, or in young ruminants, and chitosan supplementation exhibits beneficial effects against the infection caused by C. parvum. This study investigated whether chitosan supplementation modulates the gut microbiota and mediates the TLR4/STAT1 signaling pathways and related cytokines to attenuate C. parvum infection in immunosuppressed mice. Immunosuppressed C57BL/6 mice were divided into five treatment groups. The unchallenged mice received a basal diet (control), and three groups of mice challenged with 1 × 10⁶ C. parvum received a basal diet, a diet supplemented with 50 mg/kg/day paromomycin, and 1 mg/kg/day chitosan, and unchallenged mice treated with 1 mg/kg/day chitosan. Chitosan supplementation regulated serum biochemical indices and significantly (p < 0.01) reduced C. parvum oocyst excretion in infected mice treated with chitosan compared with the infected mice that received no treatment. Chitosan-fed infected mice showed significantly (p < 0.01) decreased mRNA expression levels of interferon-gamma (IFN-γ) and tumor necrosis factor-α (TNF-α) compared to infected mice that received no treatment. Chitosan significantly inhibited TLR4 and upregulated STAT1 protein expression (p < 0.01) in C. parvum-infected mice. 16S rRNA sequencing analysis revealed that chitosan supplementation increased the relative abundance of Bacteroidetes/Bacteroides, while that of Proteobacteria, Tenericutes, Defferribacteres, and Firmicutes decreased (p < 0.05). Overall, the findings revealed that chitosan supplementation can ameliorate C. parvum infection by remodeling the composition of the gut microbiota of mice, leading to mediated STAT1/TLR4 up- and downregulation and decreased production of IFN-γ and TNF-α, and these changes resulted in better resolution and control of C. parvum infection.

Synthesis and anti-Toxoplasma activity of indole-triazole compounds on tachyzoites of RH strain

Background

Conventional treatment for toxoplasmosis have severe side effects and the inability to completely eradicate the disease. Therefore, the acquisition of new anti-Toxoplasma drugs has always been of interest among researchers. In the present study, we prepare a new indole-triazole derivatives and evaluated their potential anti-parasitic activity against tachyzoites of Toxoplasma RH strain.

Materials and methods

In this study, after synthesis of the two new compounds of indole-triazole, the effect of their different concentrations (2–1024 μg/ml) were determined on Toxoplasma tachyzoites using flow cytometry. Furthermore, tachyzoites were exposed to different concentrations of compounds (4, 16, 64, 265, 1024 μg/ml) for 1.5 h and their infectivity were evaluated in BALB/c mice.

Results

The flow cytometry results indicated the benzyl derivative of indole-triazole in various concentrations had a lethal effect on tachyzoites between 11.93% and 89.66%, while the naphthalene derivative had a lethality of 26.63%–66.82%. The infectivity analysis showed that the survival time of mice at concentrations of 1024 μg/ml and 512 μg/ml of benzyl derivatives was significantly increased (P = 0.008 and P = 0.016, respectively), compared to that in the negative control group. Furthermore, survival time of mice was statistically significant at the concentration of 1024 μg/ml for naphthyl derivative (P = 0.012).

Conclusion

Findings of the current study suggested indole triazole compounds, based on their structure and enzymes targeting, have a considerable effect on tachyzoites of T. gondii RH strain and can be considered as a new anti-Toxoplasma agent.

•

The Benzyl and Naphtyl derivatives of Indol-triazol have dose dependently effect on tachyzoites of T.gondii RH strain.

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The placement of naphthyl next to indole-triazole have dose dependently effects on Toxoplasma tachyzoites.

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The benzyl derivative of Indole triazole showed an ability of over 80% in eliminating Toxoplasma tachyzoites.

Methods for the Characterization of Protein Aggregates

The physicochemical characterization of protein aggregates yields an important contribution to further our understanding on many diseases for which the formation of protein aggregates is one of the pathological hallmarks. On the other hand, bacterial inclusion bodies (IBs) have recently been shown to be highly pure proteinaceous aggregates of a few hundred nanometers, produced by recombinant bacteria supporting the biological activities of the embedded polypeptides. Despite the wide spectrum of uses of IBs as functional and biocompatible materials upon convenient engineering, very few is known about their physicochemical properties.In this chapter we present methods for the characterization of protein aggregates as particulate materials relevant to their physicochemical and nanoscale properties.Specifically, we describe the use of dynamic light scattering (DLS) for sizing, nanoparticle tracking analysis for sizing and counting, and zeta potential measurements for the determination of colloidal stability. To study the morphology of protein aggregates we present the use of atomic force microscopy (AFM) and scanning electron microscopy (SEM). Cryo-transmission electron microscopy (cryo-TEM) will be used for the determination of the internal structuration. Moreover, wettability and nanomechanical characterization can be performed using contact angle (CA) and force spectroscopic AFM (FS-AFM) measurements of the proteinaceous nanoparticles, respectively. Finally, the 4'4-dithiodipyridine (DTDP) method is presented as a way of relatively quantifying accessible sulfhydryl groups in the structure of the nanoparticle .The physical principles of the methods are briefly described and examples are given to help clarify capabilities of each technique.

In vitro and in vivo Anti-Toxoplasma Effects of Allium sativum Essential Oil Against Toxoplasma gondii RH Strain

Background

Since no effective vaccine has been developed for toxoplasmosis, prophylaxis in seronegative pregnant women and immunocompromised patients with a CD4 <100 cells/μL is highly recommended as an ideal strategy to prevent this disease. This study aimed to assess the chemical composition, in vitro, and in vivo effects of Allium sativum essential oil (ASEO) against Toxoplasma gondii RH strain.

Methods

The in vitro anti-Toxoplasma effects of different concentrations of ASEO (32.5, 75, 150 µg/mL) were measured by MTT assay for 0.5, 1, 2, and 3 h. Male Balb/c mice were orally administrated ASEO at the doses of 200, 400, and 600 µg/kg/day for 14 days. One day after the completion of oral drug administration, the mice in all groups were infected intraperitoneally with 1×10⁴ tachyzoites. They were checked daily and the rate of survival was recorded. The peritoneal fluids of the mice were collected and the mean number of tachyzoites was calculated via a light microscope. The level of liver lipid peroxidation (LPO) and nitric oxide (NO), toxicity effects on the liver and kidney, and the mRNA expression levels of some pro-inflammatory cytokines such as IL-1β and IFN-γ were determined by quantitative real-time PCR.

Results

Different concentrations of ASEO showed a significant (p < 0.001) anti-Toxoplasma activity against T. gondii tachyzoites, and the highest efficacy was observed at the concentration of 150 µg/mL. Fourteen days of pre-treatment of infected mice with ASEO at the doses of 200, 400, and 600 µg/kg/day significantly (p < 0.001) decreased the mean number of tachyzoites and mortality rate by the 6th, 7th, and 8th days after infection, respectively. ASEO at the doses of 200, 400, and 600 µg/kg/day significantly (p < 0.05) improved the increase in the LPO and NO. Pre-treatment of mice with different doses of ASEO provoked a considerable (P < 0.001) downregulation of IL-1β and IFN-γ mRNA gene expression levels, but it had no significant toxicity on the serum levels of some liver and kidney enzymes.

Conclusion

The present study demonstrated the considerable prophylactic effects of ASEO that increased the survival rate of mice and reduced the parasite load in them. Our findings also showed that ASEO promotes the innate immune system, pro-inflammatory cytokines, inhibition of hepatic injury, etc. in the mice with acute toxoplasmosis. However, additional investigations are mandatory to clarify the accurate prophylactic and therapeutic anti-Toxoplasma mechanisms of ASEO as well as all its toxicity aspects, especially in clinical settings.

Biogenic silver nanoparticles (AgNp-Bio) reduce Toxoplasma gondii infection and proliferation in HeLa cells, and induce autophagy and death of tachyzoites by apoptosis-like mechanism

Toxoplasma gondii is a protozoan parasite that can cause severe and debilitating diseases, especially in immunocompromised individuals. The available treatment is based on drugs that have low efficacy, high toxicity, several adverse effects, and need long periods of treatment. Thus, the search for therapeutic alternatives is urgently needed. Biogenic silver nanoparticles (AgNp-Bio) have been associated with several biological effects, as antiproliferative, pro-apoptotic, antioxidant, antiviral, antifungal, and antiprotozoal activity. Thus, the objective was evaluating AgNp-Bio effect on HeLa cells infected with T. gondii (RH strain). First, nontoxic AgNp-Bio concentrations for HeLa cells (1.5 - 6 µM) were determined, which were tested on cells infected with T. gondii. A significant reduction in infection, proliferation, and intracellular parasitic load was observed, also an increase in ROS and IL-6. Additionally, the evaluation of the action mechanisms of the parasite showed that AgNp-Bio acts directly on tachyzoites, inducing depolarization of the mitochondrial membrane, ROS increase, and lipid bodies accumulation, as well as triggering an autophagic process, causing damage to the parasite membrane, and phosphatidylserine exposure. Based on this, it was inferred that AgNp-Bio affects T. gondii by inducing immunomodulation and microbicidal molecules produced by infected cells, and acts on parasites, by inducing autophagy and apoptosis.

[Toxoplasma gondii-Current drugs and future vaccines against an underestimated protozoan infection]

Toxoplasma gondii is a unicellular organism of the Apicomplexa that occurs worldwide and is therefore a close relative of the malaria pathogen Plasmodium. As T. gondii infests every warm-blooded vertebrate species as an intermediate host and has a very high prevalence worldwide, toxoplasmosis is one of the most important international foodborne diseases. Potential vaccines (human as well as veterinary) play a crucial role in controlling this disease.

Lethal in vitro effects of optimized chitosan nanoparticles against protoscoleces of Echinococcus granulosus

Cystic Echinococcosis (CE) is a parasitic infection caused by the larval stage of Echinococcus granulosus. Exploring safe and effective scolicidal agents for the surgery is an urgent need for the successful treatment of CE. This study aimed to determine scolicidal activity of the synthesized chitosan nanoparticles. Physicochemical properties of synthesized nanoparticles were determined by using DLS, FTIR, and SEM. Different concentrations of chitosan nanoparticles from 125 to 1000 μg/ml were examined at different incubation times (10, 60, 120, and 180 min). Scolicidal and cytotoxic activity of chitosan nanoparticles were confirmed by eosin exclusion and hemolysis activity tests. FTIR spectra, zeta potential (+42 ± 2.08) and PDI (0.388 ± 0.034) value revealed that the chitosan nanoparticles were synthesized. Significant differences among the scolicidal effects of chitosan nanoparticles were observed in comparison to the control treatments and highest scolicidal activity was observed at 1000 μg/ml after 180 min exposure time. Hemolytic activity was not significant at all concentrations of chitosan nanoparticles. Our findings support the hypothesis that Chitosan nanoparticles have the potential to be a safe and efficient scolicidal agent candidate at very low concentrations and in a wide range of exposure time. Further in vivo studies are recommended to evaluate chitosan nanoparticle efficacy before clinical application.

Advances in Toxoplasma gondii Vaccines: Current Strategies and Challenges for Vaccine Development

Toxoplasmosis, caused by the apicomplexan parasite Toxoplasma gondii, is one of the most damaging parasite-borne zoonotic diseases of global importance. While approximately one-third of the entire world’s population is estimated to be infected with T. gondii, an effective vaccine for human use remains unavailable. Global efforts in pursuit of developing a T. gondii vaccine have been ongoing for decades, and novel innovative approaches have been introduced to aid this process. A wide array of vaccination strategies have been conducted to date including, but not limited to, nucleic acids, protein subunits, attenuated vaccines, and nanoparticles, which have been assessed in rodents with promising results. Yet, translation of these in vivo results into clinical studies remains a major obstacle that needs to be overcome. In this review, we will aim to summarize the current advances in T. gondii vaccine strategies and address the challenges hindering vaccine development.

Albalawi A, Alanazi AD, Baharvand P, Moghaddam A, Mahmoudvand H. Chitosan-Based Nanomaterials as Valuable Sources of Anti-Leishmanial Agents: A Systematic Review

BACKGROUND

The current chemotherapy agents against various forms of leishmaniasis have some problems and side effects, including high toxicity, high cost, and the emergence of resistant strains. Here, we aimed to review the preclinical studies (in vitro and in vivo) on the anti-leishmanial activity of chitosan and chitosan-based particles against Leishmania spp.

METHODS

This study was conducted based on the 06-PRISMA guidelines and registered in the CAMARADES-NC3Rs Preclinical Systematic Review and Meta-Analysis Facility (SyRF) database. Various English databases such as PubMed, Google Scholar, Web of Science, EBSCO, ScienceDirect, and Scopus were used to find the publications related to the anti-leishmanial effects of chitosan and its derivatives and other pharmaceutical formulations, without a date limitation, to find all the published articles. The keywords included "chitosan", "chitosan nanoparticles", "anti-leishmanial", "Leishmania", "leishmaniasis", "cutaneous leishmaniasis", "visceral leishmaniasis", "in vitro", and "in vivo". The language for data collection were limited to English.

RESULTS

Of 2669 papers, 25 papers, including 7 in vitro (28.0%), 7 in vivo (28.0%), and 11 in vitro/in vivo (44.0%) studies conducted up to 2020 met the inclusion criteria for discussion in this systematic review. The most common species of Leishmania used in these studies were L. major (12, 48.0%), L. donovani (7, 28.0%), and L. amazonensis (4, 16.80%). In vivo, the most used animals were BALB/c mice (11, 61.1%) followed by hamsters (6, 33.3%) and Wistar rats (1, 5.5%), respectively. In vitro, the most used Leishmania form was amastigote (8, 44.4%), followed by promastigote (4, 22.2%), and both forms promastigote/amastigote (6, 33.3%).

CONCLUSION

According to the literature, different types of drugs based on chitosan and their derivatives demonstrated considerable in vitro and in vivo anti-leishmanial activity against various Leishmania spp. Based on the findings of this review study, chitosan and its derivatives could be considered as an alternative and complementary source of valuable components against leishmaniasis with a high safety index. Nevertheless, more investigations are required to elaborate on this result, mainly in clinical settings.

Unravelling Toxoplasma treatment: conventional drugs toward nanomedicine

Toxoplasma gondii is a worldwide protozoan parasite that infects almost all warm-blooded animals. Although human toxoplasmosis is mostly latent, pregnant women and immunocompromised patients need effective treatment. There are drugs of choice for treatment of toxoplasmosis; however, due to their side effects and/or their disease stage-specificity, prescription of them is limited. During recent years, nanomedicine has been employed to overcome limitations of conventional drugs. Here, we provided a state-of-the-art review of experimental toxoplasmosis treatment using nanotechnology.

Control of human toxoplasmosis

Toxoplasmosis is caused by Toxoplasma gondii, an apicomplexan parasite that is able to infect any nucleated cell in any warm-blooded animal. Toxoplasma gondii infects around 2 billion people and, whilst only a small percentage of infected people will suffer serious disease, the prevalence of the parasite makes it one of the most damaging zoonotic diseases in the world. Toxoplasmosis is a disease with multiple manifestations: it can cause a fatal encephalitis in immunosuppressed people; if first contracted during pregnancy, it can cause miscarriage or congenital defects in the neonate; and it can cause serious ocular disease, even in immunocompetent people. The disease has a complex epidemiology, being transmitted by ingestion of oocysts that are shed in the faeces of definitive feline hosts and contaminate water, soil and crops, or by consumption of intracellular cysts in undercooked meat from intermediate hosts. In this review we examine current and future approaches to control toxoplasmosis, which encompass a variety of measures that target different components of the life cycle of T. gondii. These include: education programs about the parasite and avoidance of contact with infectious stages; biosecurity and sanitation to ensure food and water safety; chemo- and immunotherapeutics to control active infections and disease; prophylactic options to prevent acquisition of infection by livestock and cyst formation in meat; and vaccines to prevent shedding of oocysts by definitive feline hosts.

Modulation Effects of Toxoplasma gondii Histone H2A1 on Murine Macrophages and Encapsulation with Polymer as a Vaccine Candidate

Toxoplasma gondii (T. gondii) is the most common zoonotic protozoa and has infected about one-third of the population worldwide. Recombinant epitopes encapsulated in nanospheres have advantages over traditional T. gondii vaccines. For an efficient delivery system, poly (DL-lactide-co-glycolide) (PLGA) and chitosan are the most frequently used biodegradable polymeric nanospheres with strong safety profiles. In the present study, we first expressed and purified histone H2A1 of T. gondii using the prokaryotic expression system. The effects of recombinant TgH2A1 on the functions of murine macrophages were then studied. Purified recombinant TgH2A1 was then encapsulated in nanospheres with PLGA and chitosan. After subcutaneous vaccination in mice, the immune response was evaluated by double antibody sandwich ELISA kits. The results from this study showed that PLGA and chitosan loaded with rTgH2A1 could trigger a stronger Th1 oriented immune response and prolong the survival time of mice effectively. In conclusion, PLGA and chitosan nanospheres loaded with histone H2A1 are an effective method for the development of vaccines against T. gondii. Further studies should focus on evaluating the regulatory mechanism of TgH2A1, vaccine potency, and cellular response in chronic T. gondii infections.

Effect of chitosan on Toxoplasma gondii infection: A systematic review

Background

The preferred treatment for management of toxoplasmosis is the combined use of pyrimethamine and sulfadiazine. However, there are a wide number of adverse side effects with these medications. Recent research has focused on the use of chitosan for the treatment of Toxoplasma gondii infections. This review was performed to obtain a better understanding of the in vivo and in vitro effects of chitosan on T. gondii strains.

Methods

The current study was carried out according to the PRISMA guideline and registered in the CAMARADES-NC3Rs Preclinical Systematic Review and Meta-analysis Facility (SyRF) database. The search was performed in five scientific databases, including Scopus, PubMed, Web of Science, EMBASE, and Google Scholar, with date limits of 1992 to December 2019. The search was restricted to articles published in the English language. The words and terms searched were "Toxoplasma gondii", "Chitosan", "nanoparticles" and "anti-toxoplasmosis" with AND or OR.

Results

Of 2500 manuscripts, 9 met the eligibility criteria for review. All studies used the RH strain of T. gondii, with Me49 and PRU each included in one study. Five studies (56%) were performed in vivo, one study in vitro and 3 studies included in vivo and in vitro tests.

Conclusion

Considering the low toxicity and the high inhibitory potency of chitosan against T. gondii, chitosan nanoparticles show potential as an alternative treatment for T. gondii infections.

Silver Nanoparticle-Induced Apoptosis in ARPE-19 Cells Is Inhibited by Toxoplasma gondii Pre-Infection Through Suppression of NOX4-Dependent ROS Generation

Purpose

External and internal stimuli easily affect the retina. Studies have shown that cells infected with Toxoplasma gondii are resistant to multiple inducers of apoptosis. Nanoparticles (NPs) have been widely used in biomedical fields; however, little is known about cytotoxicity caused by NPs in the retina and the modulators that inhibit nanotoxicity.

Materials and Methods

ARPE-19 cells from human retinal pigment epithelium were treated with silver nanoparticles (AgNPs) alone or in combination with T. gondii. Then, the cellular toxicity, apoptosis, cell cycle analysis, autophagy, ROS generation, NOX4 expression, and MAPK/mTOR signaling pathways were investigated. To confirm the AgNP-induced cytotoxicity in ARPE-19 cells and its modulatory effects caused by T. gondii infection, the major experiments carried out in ARPE-19 cells were performed again using human foreskin fibroblast (HFF) cells and bone marrow-derived macrophages (BMDMs) from NOX4^−/− mice.

Results

AgNPs dose-dependently induced cytotoxicity and cell death in ARPE-19 cells. Apoptosis, sub-G1 phase cell accumulation, autophagy, JNK phosphorylation, and mitochondrial apoptotic features, such as caspase-3 and PARP cleavages, mitochondrial membrane potential depolarization, and cytochrome c release into the cytosol were observed in AgNP-treated cells. AgNP treatment also increased the Bax, Bik, and Bim protein levels as well as NOX4-dependent ROS generation. However, T. gondii-infected ARPE-19 cells inhibited AgNP-induced apoptosis, JNK phosphorylation, sub-G1 phase cell accumulation, autophagy, NOX4-mediated ROS production, and mitochondrial apoptosis. Furthermore, mitochondrial apoptosis was found in AgNP-treated HFF cells and BMDMs, and AgNP-induced mitochondrial apoptosis inhibition via NOX4-dependent ROS suppression in T. gondii pre-infected HFF cells and BMDMs was also confirmed.

Conclusion

AgNPs induced mitochondrial apoptosis in human RPE cells combined with cell cycle dysregulation and autophagy; however, these effects were significantly inhibited by T. gondii pre-infection by suppression of NOX4-mediated ROS production, suggesting that T. gondii is a strong inhibitory modulator of nanotoxicity in in vitro models.

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.

Effect of Polysaccharide Sources on the Physicochemical Properties of Bromelain-Chitosan Nanoparticles

Bromelain, a set of proteolytic enzymes potential pharmaceutical applications, was encapsulated in chitosan nanoparticles to enhance enzyme stability, and the effect of different chitosan sources was evaluated. Chitosan types (i.e., low molecular weight chitosan, chitosan oligosaccharide lactate, and chitosan from shrimp shells) produced nanoparticles with different physicochemical properties, however in all cases, particle size and zeta potential decreased, and polydispersity index increased after bromelain addition. Bromelain encapsulation was higher than 84% and 79% for protein content and enzymatic activity, respectively, with low molecular weight chitosan presenting the highest encapsulation efficiency. Nanoparticle suspension was also tested for accelerated stability and rheological behavior. For the chitosan-bromelain nanoparticles, an instability index below 0.3 was recorded and, in general, the loading of bromelain in chitosan nanoparticles decreased the cohesiveness of the final suspension.

Development, optimization, and validation of an in-house Dot-ELISA rapid test based on SAG1 and GRA7 proteins for serological detection of Toxoplasma gondii infections

Background

The aim of the present study was to develop a simple, portable, and rapid assay for serodiagnosis of toxoplasmosis based on recombinant Toxoplasma gondii (T. gondii) SAG1 (rSAG1) and GRA7 (rGRA7) proteins.

Methods

The rSAG1 and rGRA7 proteins were expressed in Escherichia coli (E. coli) and purified in a single step by immobilized metal ion affinity chromatography. The immunoreactivity of the recombinant antigens was tested in an in-house IgG and IgM Dot enzyme-linked immunosorbent assay (Dot-ELISA) for potential use in serodiagnosis of T. gondii infection.

Results

Results from the comparison of in-house rSAG1-Dot-ELISA with ELISA for the detection of anti-Toxoplasma IgG and IgM include sensitivity of 83.7% and 81.2%, specificity of 90.2% and 89.3%, positive predictive values of 85.9% and 68.4%, and negative predictive values of 88.6% and 94.3%, respectively. Sensitivity of 66.2%, specificity of 81.2%, positive predictive values of 71.6%, and negative predictive values of 77.1% were concluded from in-house IgG rGRA7-Dot-ELISA. The sensitivity and specificity of IgM rGRA7-Dot-ELISA included 87.5% and 83.9%, respectively. Sensitivity and specificity of in-house Dot-ELISA for a combination of rSAG1 and rGRA7 included 87.5% and 91.1% for IgG and IgM, respectively. Sensitivity and specificity of a combination of rSAG1 and rGRA7 for the detection of IgM in suspected sera to acute toxoplasmosis were higher than those for the detection of IgG in sera with chronic infections (90.6% and 92% instead of 86.2% and 91.6%, respectively).

Conclusion

The highlighted parameters of combined recombinant proteins were more significant than those of single recombinant proteins in in-house Dot-ELISA. These data suggest that the in-house Dot-ELISA based on rSAG1 and rGRA7 combination is a promising diagnostic tool with a similar sensitivity to the native antigens of T. gondii, which can be used for the serodiagnosis of toxoplasmosis in fields as well as less equipped laboratories.

Assessment of the immunogenicity and protective efficiency of a novel dual-promoter DNA vaccine, harboring SAG1 and GRA7 genes, from RH strain of Toxoplasma gondii in BALB/c mice

BACKGROUND

Toxoplasmosis, a protozoan parasitic disease caused by Toxoplasma gondii, has been a serious human and veterinary medicine problem with global distribution. In the current study, we assessed immunogenicity and protective efficiency of a novel dual-promoter DNA vaccine, harboring SAG1 and GRA7 genes, from RH strain of Toxoplasma gondii (T. gondii) with or without CpG-ODN as adjuvant in a murine model.

METHODS

BALB/c mice were immunized intramuscularly with pVitro-SAG1-GRA7 alone and pVitro-SAG1-GRA7 with CpG-ODN three times at three-week intervals. Enzyme-linked immunosorbent assay (ELISA) was used to assess total IgG, IgG1 and IgG2a antibodies and gamma interferon (IFN-γ) and interleukin-10 (IL-10) cytokines in mice sera. Four weeks post final vaccination, MTT assay and lethal challenge-infection with 1×103 tachyzoites of T. gondii RH strain were carried out to assess stimulation index (SI) and mice survival time, respectively.

RESULTS

The IgG levels in mice immunized with multicomponent vaccines, including pVitro-SAG1-GRA7 alone and pVitro-SAG1-GRA7 with CpG-ODN, were significantly higher than those in control mice or single-gene DNA-vaccinated ones (P<0.05). Furthermore, level of IgG2a in mice receiving pVitro-SAG1-GRA7 with CpG-ODN was significantly higher than that in mice receiving pVitro-SAG1-GRA7 alone (P<0.05). The Toxoplasma lysate antigen (TLA)-stimulated lymphocytes from pVitro-SAG1-GRA7 with CpG-ODN group responded more dramatically than those from control groups or single-gene DNA-vaccinated groups (P<0.001). The pVitro-SAG1-GRA7 with CpG-ODN-vaccinated mice developed high levels of IgG2a and IFN-γ (P<0.001) and low levels of IgG1 and IL-10, compared to control groups, suggesting a modulated immune response type Th1. In addition, survival time of the mice immunized with pVitro-SAG1-GRA7 with CpG-ODN was significantly extended, compared to controls (P<0.05); however, all mice died.

CONCLUSION

The multivalent pVitro-SAG1-GRA7 DNA vaccine with CpG-ODN adjuvant is a promising vaccine candidate against toxoplasmosis.

Inhibitory activity of chitosan nanoparticles against Cryptosporidium parvum oocysts

Cryptosporidium is a ubiquitous harsh protozoan parasite that resists many disinfectants. It remains viable and infective for a long time in water and food causing global outbreaks. Chitosan (the deacetylated chitin molecule) was used in its nanosuspension form to evaluate its effect against Cryptosporidium parvum. The experiments were performed in vitro in serial concentrations and confirmed in mice in vivo infectivity assay. Chitosan nanoparticles (Cs NPs) were toxic to Cryptosporidium oocysts. The effect appeared to decrease the number of Cryptosporidium oocysts and altered their content. The destruction rate of oocysts was dependent on the dose of chitosan and the time of exposure (P < 0.05). Higher doses of Cs NPs over a prolonged period exhibited a significantly higher destruction rate. Using staining and light microscopy, remarkable destructive changes were observed in the oocysts' morphology. The minimal lethal dose for > 90% of oocysts was 3000 μg/ml, no mice infections in vivo were observed. The results in this study elucidate Cs NPs as an effective anti-cryptosporidial agent.

Treatment of toxoplasmosis: Current options and future perspectives

Toxoplasmosis is a worldwide parasitic disease infecting about one third of humans, with possible severe outcomes in neonates and immunocompromised patients. Despite continuous and successful efforts to improve diagnosis, therapeutic schemes have barely evolved since many years. This article aims at reviewing the main clinical trials and current treatment practices, and at addressing future perspectives in the light of ongoing researches.

Nanosilver Colloid Inhibits Toxoplasma gondii Tachyzoites and Bradyzoites in Vitro

BACKGROUND

Toxoplasma gondii, the coccidian protozoan parasite with worldwide distribution, is the agent of toxoplasmosis. The disease is life threatening in congenital form and in immunocompromised patients. The present study was carried out in 2016 to evaluate the in vitro effects of nanosilver colloid on tachyzoites and bradyzoites of T. gondii, RH and Tehran strains.

METHODS

Different concentrations (5, 10, 20 ppm) of nanosilver colloid were added to tachyzoites of T. gondii, RH strain (type I) and bradyzoites and tissue cysts of T. gondii, Tehran strain (type II) and incubated for 30, 60, 90 and 120 minutes. The mortality rates of tachyzoites and bradyzoites were evaluated by trypan blue dye and MTT assay. Then SEM carried out to show the changes between control and exposed parasites.

RESULTS

The greatest mortality rate was seen in 20 ppm concentration and after 120 minutes of exposure. By electron microscopy, the structural changes were seen in tachyzoites of RH and tissue cyst of Tehran strain in comparison with control groups.

CONCLUSION

Nanosilver colloid was effective on both tachyzoites and bradyzoites of T. gondii, RH and Tehran strains.

The relation of serum prolactin levels and Toxoplasma infection in humans

BACKGROUND

Toxoplasma gondii is an intracellular protozoan parasite distributed worldwide. Although the infection is benign in immunocompetent individuals, it is life threatening and complicated in immunocompromised patients and fetuses of pregnant women who received their first exposure to T. gondii during the pregnancy. Prolactin (PRL) is a hormone that is secreted by the pituitary gland, and it is confirmed that it plays a role in the immune system. The present study was carried out to assess the possible relation between serum PRL levels and Toxoplasma infection frequency in human.

METHODS

In this cross-sectional study, 343 serum samples (240 from women and 103 from men) were collected from individuals who were referred for PRL checking in laboratories of Karaj, Iran. Blood samples were collected, and sera were separated and analyzed for the detection of anti-Toxoplasma IgG antibody by ELISA method. The levels of PRL were measured by Roche Elecsys 2010 analyzer, electrochemiluminescence technology.

RESULTS

Of 343 sera, 110 samples (32%) consisting of samples from 42 men and 68 women had anti-T. gondii IgG antibody. The prevalence of T. gondii infection in women with high PRL levels was lower than that in the comparison group with normal levels of PRL and the relationship between these two parameters was statistically significant (P=0.016). In women with hyperprolactinemia, by increasing of PRL levels, the prevalence of T. gondii infection was reduced.

CONCLUSION

The results of the current study confirmed the previous studies based on immunoregulatory role of PRL and indicated that high levels of PRL could be related to Toxoplasma seronegativity in women.

Curcumin nanoemulsion as a novel chemical for the treatment of acute and chronic toxoplasmosis in mice

Background

The aim of this study was to prepare curcumin nanoemulsion (CR-NE) to solve the problems associated with poor water solubility and low bioavailability of CR and to test its efficiency in the treatment of acute and chronic toxoplasmosis in mouse models.

Materials and methods

CR-NE 1% was prepared using spontaneous emulsification by soybean as oil phase; a mixture of Tween 80 and Tween 85 as surfactant; ethanol as cosurfactant and distilled water. Particle size and zeta potential of NE were assessed using Nano-ZS90 dynamic light scattering. Stability testing of NE was assessed after storage for 2 months at room temperature. In vivo experiments were carried out using 50 BALB/c mice inoculated with virulent RH strain (type I) and 50 BALB/c mice inoculated with avirulent Tehran strain (type II) of Toxoplasma gondii and treated with CR-NE (1% w/v), CR suspension (CR-S, 1% w/v), and NE without CR (NE-no CR).

Results

The mean particle size and zeta potential of CR-NE included 215.66±16.8 nm and −29.46±2.65 mV, respectively, and were stable in particle size after a three freeze–thaw cycle. In acute phase experiment, the survival time of mice infected with RH strain of T. gondii and treated with CR-NE extended from 8 to 10 days postinoculation. The differences were statistically significant between the survival time of mice in CR-NE-treated group compared with negative control group (P<0.001). Furthermore, CR-NE significantly decreased the mean counts of peritoneum tachyzoites from 5,962.5±666 in negative control group to 627.5±73 in CR-NE-treated mice (P<0.001). Growth inhibition rates of tachyzoites in peritoneum of mice receiving CR-NE, CR-S, and NE-no CR included 90%, 21%, and 11%, respectively, compared with negative control group. In chronic phase experiment, the average number and size of tissue cysts significantly decreased to 17.2±15.6 and 31.5±6.26 µm, respectively, in mice inoculated with bradyzoites of T. gondii Tehran strain and treated with CR-NE compared with that in negative control group (P<0.001). Decrease of cyst numbers was verified by downregulation of BAG1 in treatment groups compared with negative control group with a minimum relative expression in CR-NE (1.12±0.28), CR-S (11.76±0.87), and NE-no CR (14.67±0.77), respectively, (P<0.001).

Conclusion

Results from the current study showed the potential of CR-S and CR-NE in treatment of acute and chronic toxoplasmosis in mouse models for the first time. However, CR-NE was more efficient than CR-S, and it seems that CR-NE has a potential formula for the treatment of acute and chronic toxoplasmosis, especially in those with latent bradyzoites in brain.

The relation of secondary sex ratio and miscarriage history with Toxoplasma gondii infection

Background

Toxoplasma gondii is a protozoan parasite with worldwide distribution, infecting a broad-range of humans and warm-blooded animals. In the current study, role of this parasite on secondary sex ratio and risk of miscarriage was investigated.

Methods

In this cross-sectional study, 850 cord blood samples were collected in Tehran, Iran, 2014–2015. Enzyme-linked immunosorbent assay (ELISA) was used to assess anti-Toxoplasma IgG in samples. Information such as sex of the neonates and age, number of previous pregnancies and history of miscarriage of the mothers were recorded in questionnaires. Logistic regression analysis was used to assess the possible relationship between the latent toxoplasmosis and the highlighted parameters.

Results

Logistic regression analysis showed that the odds of having a male neonate in seropositive women is nearly 64% higher than that in seronegative women (OR = 1.64, CI₉₅ = 1.16–2.33, P = 0.005). The odds ratio of having male neonate increased to 2.10 (CI₉₅ = 1.24–3.57, P = 0.006) in high-titer seropositive women, compared to that in seronegative control group. The odds of having a miscarriage history was approximately two and a half times greater in seropositive women than in seronegative ones (OR = 2.45, CI₉₅ = 1.56–3.87, P < 0.001). The odds ratio of having miscarriage increased to 2.76 (CI₉₅ = 1.61–4.73, P < < .001) in low-titer seropositive women, compared to that in seronegative control group.

Conclusion

Results of the current study have shown that T. gondii infection affects secondary sex ratio in human offspring and can be addressed as one of the major miscarriage causes in women.

The association of latent toxoplasmosis and level of serum testosterone in humans

Objectives

Latent toxoplasmosis modifies various hormones and behaviors in infected hosts and possibly involves in etiology of different neurologic and psychiatric disorders. The aim of the current study was to assess possible associations between latent toxoplasmosis and testosterone concentration in Toxoplasma infected and free subjects. Briefly, 18–49 year-old participated in the study. After collected blood samples, sera were analyzed for the detection of anti-Toxoplasma IgG antibody. Totally, 76 positive sera were selected as study group (38 from men and 38 from women) and a same number of negative sera as control group.

Results

Comparison of testosterone concentrations and control groups showed that testosterone concentration in study group was higher than that in control group with statistically significant difference (P = 0.024 and P = 0.043 for men and women, respectively). Significant differences were found in testosterone concentrations and anti-Toxoplasma IgG antibody levels in study and control groups (P < 0.05). Toxoplasmosis can affect the mean concentration of serum testosterone in human. Alteration of testosterone during latent toxoplasmosis can result in alterations in behavioral, physiologic and immunological parameters in long time.