Effect of diminazene aceturate, levamisole and vitamin C combination therapy in rats experimentally infected with Trypanosoma brucei brucei

Comprehensive analysis of oral administration of Vitamin E on the early stage of Trypanosoma brucei brucei infection

Reinforcement of the body with exogenous antioxidants have been shown to mitigate the negative effects of African trypanosomiasis on the host and contribute greatly to their survival. This study was therefore conducted to evaluate the effects of oral administration of Vitamin E on the early stage of Trypanosoma brucei brucei infection. To achieve this, parasite free healthy rats were acclimatized for 2 weeks before they were divided into three groups. Two of the groups were infected by intraperitoneal inoculation of 1 × 10⁴ parasites/rat and monitored for the presence of Trypanosoma brucei brucei. Blood samples were collected from the infected rats from the second day post infection to detect the presence of parasites. Vitamin E treatment started day 4 post infection at the onset of parasitaemia. Parasites were monitored till the end of the study. The blood glucose level was determined using a glucometer; the lipid profile, liver and kidney biomarkers, electrolytes and protein were determined by colorimetric method using commercial kits. Haematological parameters were analysed using a sysmex haematology analyser. The results of this study showed that the infection adversely affected the biomarkers examined showing its negative effect on liver, kidney, haematological parameters and host electrolyte balance. Treatments with Vitamin E was however able to mitigate the negative effect of this infection. In conclusion, the treatment was able to ameliorate the anaemia and organ damage caused by Trypanosoma brucei brucei, extend the life span of the treated rats and greatly delay the time taken to get to the second stage of the infection.

Cruzipain and Its Physiological Inhibitor, Chagasin, as a DNA-Based Therapeutic Vaccine Against Trypanosoma cruzi

Chagas disease caused by the protozoan parasite Trypanosoma cruzi is endemic in 21 Latin American countries and the southern United States and now is spreading into several other countries due to migration. Despite the efforts to control the vector throughout the Americas, currently, there are almost seven million infected people worldwide, causing ~10,000 deaths per year, and 70 million people at risk to acquire the infection. Chagas disease treatment is restricted only to two parasiticidal drugs, benznidazole and nifurtimox, which are effective during the acute and early infections but have not been found to be as effective in chronic infection. No prophylactic or therapeutic vaccine for human use has been communicated at this moment. Here, we evaluate in a mouse model a therapeutic DNA vaccine combining Cruzipain (Cz), a T. cruzi cysteine protease that proved to be protective in several settings, and Chagasin (Chg), which is the natural Cz inhibitor. The DNAs of both antigens, as well as a plasmid encoding GM-CSF as adjuvant, were orally administrated and delivered by an attenuated Salmonella strain to treat mice during the acute phase of T. cruzi infection. The bicomponent vaccine based on Salmonella carrying Cz and Chg (SChg+SCz) was able to improve the protection obtained by each antigen as monocomponent therapeutic vaccine and significantly increased the titers of antigen- and parasite-specific antibodies. More importantly, the bicomponent vaccine triggered a robust cellular response with interferon gamma (IFN-γ) secretion that rapidly reduced the parasitemia during the acute phase and decreased the tissue damage in the chronic stage of the infection, suggesting it could be an effective tool to ameliorate the pathology associated to Chagas disease.

Successful Aspects of the Coadministration of Sterol 14α-Demethylase Inhibitor VFV and Benznidazole in Experimental Mouse Models of Chagas Disease Caused by the Drug-Resistant Strain of Trypanosoma cruzi

Up to now, no vaccines are available for Chagas disease, and the current therapy is largely unsatisfactory. Novel imidazole-based scaffolds of protozoan sterol 14α-demethylase (CYP51) inhibitors have demonstrated potent antiparasitic activity with no acute toxicity. Presently our aim was to investigate the effectiveness of the experimental 14α-demethylase inhibitor VFV in the mouse models of Trypanosoma cruzi infection using a naturally drug-resistant Colombiana strain, under monotherapy and in association with the reference drug, benznidazole (Bz). The treatment with VFV resulted in complete parasitemia suppression and 100% animal survival when administered orally (given in 10% DMSO plus 5% Arabic gum) at 25 mg/kg (bid) for 60 days. However, as parasite relapse was found using VFV alone under this treatment scheme, the coadministration of VFV with Bz was assayed giving simultaneously (for 60 days, bid) by oral route, under two different drug vehicles (10% DMSO plus 5% Gum Arabic with or without 3% Tween 80). All tested mice groups resulted in >99.9% of parasitemia decrease and 100% animal survival. qPCR analysis performed on cyclophosphamide immunosuppressed mice revealed that, although presenting lack of cure, VFV given as monotherapy was 14-fold more active than Bz, and the coadministration of Bz plus VFV (given simultaneously, using 10% DMSO plus 5% Gum Arabic as vehicle) resulted in 106-fold lower blood parasitism as compared to the monotherapy of Bz. Another interesting finding was the parasitological cure in 70% of the animals treated with Bz and VFV when the coadministration was given using the VFV suspension in 10% DMSO + Arabic gum + Tween 80 (a formulation that we have found to provide a better pharmacokinetics), even after immunosuppression using cyclophosphamide cycles, supporting the promising aspect of the drug coadministration in improving the efficacy of therapeutic arsenal against T. cruzi.

Host-Directed Drug Therapies for Neglected Tropical Diseases Caused by Protozoan Parasites

The neglected tropical diseases (NTDs) caused by protozoan parasites are responsible for significant morbidity and mortality worldwide. Current treatments using anti-parasitic drugs are toxic and prolonged with poor patient compliance. In addition, emergence of drug-resistant parasites is increasing worldwide. Hence, there is a need for safer and better therapeutics for these infections. Host-directed therapy using drugs that target host pathways required for pathogen survival or its clearance is a promising approach for treating infections. This review will give a summary of the current status and advances of host-targeted therapies for treating NTDs caused by protozoa.

Achillea fragrantissima, rich in flavonoids and tannins, potentiates the activity of diminazine aceturate against Trypanosoma evansi in rats

OBJECTIVE

To evaluate activity of methanol extract of Achillea fragrantissima (meth) (A. fragrantissima) alone or in combination with diminazine aceturate (DA) against Trypanosoma evansi (T. evansi) in experimentally infected rats.

METHODS

Sixty adult male Wister albino rats were divided equally into 6 groups (A-F). Rats in groups A-E were experimentally infected with T. evansi and those in group F were uninfected. The groups were treated respectively as follows: group A-with 3.5 mg/kg DA; group B- with 1000 mg/kg meth A. fragrantissima; group C-3.5 mg/kg DA plus 500 mg/kg meth A. fragrantissima; group D-3.5 mg/kg DA plus 1000 mg/kg meth A. fragrantissima. Group E was left untreated. Parasitemia, survivability, packed cell volume, hemoglobin concentration, total leucocytes count, lymphocyte count, and serum malondialdehyde and reduced glutathione (GSH) levels were estimated. Phytochemical screening of meth A. fragrantissima was also performed.

RESULTS

The phytochemical analysis of the meth A. fragrantissima indicated a higher content from polyphenolic tannins and non tannins and flavonoids. The efficacy percentage against trypanosomiasis in groups A - E was respectively as follows 80, 40, 90, 100, 0. The administration of meth-A. fragrantissima (1000 mg/kg b.wt.) produced a moderate efficacy against trypanosomiasis. Untreated rats in group E died between 25 and 30 d post infection. The rats given DA and meth A. fragrantissima combinations (C and D) showed faster and higher recovery rates than the uninfected control and groups A and B. The initial reduction in packed cell volume, hemoglobin, total leucocytes count, increases in serum malondialdehyde and decreases in GSH levels were reversed by the treatments.

CONCLUSION

The administration of the methanol extracts of A. fragrantissima and DA combination therapy was more effective than each product alone in the treatment of rats infected with T. evansi and further studies are required to isolate more active ingredients.