Parameters for evaluation of clinical trial in mice infected with Trypanosoma cruzi

Immunological Modulation and Control of Parasitaemia by Ayahuasca Compounds: Therapeutic Potential for Chagas's Disease

Ayahuasca is a psychoactive and psychedelic decoct composed mainly of Banisteriopsis caapi and Psychotria viridis plant species. The beverage is rich in alkaloids and it is ritualistically used by several indigenous communities of South America as a natural medicine. There are also reports in the literature indicating the prophylaxis potential of Ayahuasca alkaloids against internal parasites. In the present study, Ayahuasca exhibited moderate in vitro activity against Trypanosoma cruzi trypomastigotes (IC₅₀ 95.78 μg/mL) compared to the reference drug benznidazole (IC₅₀ 2.03 μg/mL). The β-carboline alkaloid harmine (HRE), isolated from B. caapi, was considered active against the trypomastigotes forms (IC₅₀ 6.37), and the tryptamine N, N-dimethyltryptamine (DMT), isolated from P. viridis was also moderately active with IC₅₀ of 21.02 μg/mL. Regarding the in vivo evaluations, no collateral effects were observed. The HRE alone demonstrated the highest trypanocidal activity in a dose-responsive manner (10 and 100 mg/kg). The Ayahuasca and the association between HRE and DMT worsened the parasitaemia, suggesting a modulation of the immunological response during the T. cruzi infection, especially by increasing total Immunoglobulin (IgG) and IgG1 antibody levels. The in silico molecular docking revealed HRE binding with low energy at two sites of the Trypanothione reductase enzyme (TR), which are absent in humans, and thus considered a promissory target for drug discovery. In conclusion, Ayahuasca compounds seem to not be toxic at the concentrations of the in vivo evaluations and can promote trypanocidal effect in multi targets, including control of parasitaemia, immunological modulation and TR enzymatic inhibition, which might benefit the treatments of patients with Chagas' disease. Moreover, the present study also provides scientific information to support the prophylactic potential of Ayahuasca against internal parasites.

Assemblages A and B of Giardia duodenalis reduce enteric glial cells in the small intestine in mice

Infection of Giardia duodenalis is one of the most common human parasitic disease worldwide. This infection may be related to important changes in the enteric nervous system. The objective of this study was to evaluate the myenteric and submucosal plexuses, the intestinal muscle layer, and gastrointestinal transit in mice infected with assemblages A and B of G. duodenalis. Swiss albino mice (Mus musculus) were infected with assemblages A and B of G. duodenalis for 15 days. Gastrointestinal transit time was evaluated before euthanasia. Duodenum and jejunum were removed for histological and immunohistochemical analyses. It was observed a reduction in the enteric glial cell count and a decrease in the ratio of enteric glial cells to neurons. The number of neurons did not change, but morphological changes were observed in the duodenum and jejunum in both plexuses, including an increase in the nuclear area and a reduction of cell bodies in the myenteric plexus and a decrease in the nuclear area in the submucosal plexus. A reduction of the thickness of the muscle layer was observed in the duodenum, with no significant differences in the gastrointestinal transit times. Assemblages A and B of G. duodenalis decrease the number of enteric glial cells in the myenteric and submucosal plexuses, decrease the thickness of the muscle layer, and change the morphology of neurons. Graphical abstract ᅟ.

Different treatment schemes and dynamizations of Trypanosoma cruzi biotherapies: what information do they transfer to the organism in infected mice?

BACKGROUND

The use of biotherapies in Trypanosoma cruzi infection can provide an understanding about effects of these highly diluted medications.

OBJECTIVES

To evaluate different treatment schemes and dynamizations of biotherapies prepared from blood trypomastigotes (buffy coat) in mice infected with T. cruzi.

METHODS

Swiss mice infected with Y strain of T. cruzi were divided into two experiments. Experiment 1, all treated groups received biotherapy 7dH (10 μL/mL ad libitum) in different treatment schemes: TB_7dH - treated 3 days before infection; TBA_7dH - treated 3 days before and after infection; TBAe.d._7dH - treated 3 days before infection and every day after infection and IC - infection control. Experiment 2, all treated groups received medication in different dynamizations 3 days before and after infection (10 μL/mL ad libitum): TBA_15dH - treated with biotherapy 15dH; TBA_16dH - treated with biotherapy 16dH; TBA_17dH - treated with biotherapy 17dH; TBA_p.chords - treated with biotherapy 'potency chords' and IC - infection control. We evaluated parasitological and clinical parameters.

RESULTS

Experiment 1 showed that different treatment schemes with biotherapy 7dH produced different effects on infection evolution. TBA_7dH group had the best outcome, with lower parasitemia, higher survival, and better clinical evolution compared to IC. Experiment 2 showed that biotherapy 'potency chords' had effects different from the individual dynamizations that it contained (15dH, 16dH, and 17dH). Animals that had patent parasitemia had delayed emergence of parasites in blood and subsequent increase in parasitemia, but had better clinical evolution compared to IC.

CONCLUSIONS

The effects of T. cruzi biotherapies depend on frequency at which they are administered, dynamization, and host-parasite relationship/individual susceptibility of treated organism. Biotherapy appeared to transfer to infected organism 'antigenic information' related to parasite and 'disease information' related to molecules produced by host's immune response and contained in the buffy coat used to prepare the medication.