Trypanosoma evansi impacts on embryonic neural progenitor cell functions

Trypanosoma evansi appears to have a significant tropism for brain tissue in its chronic and acute phases. The most common symptoms of this brain infection are motor incoordination, meningoencephalitis, demyelination, and anemia. There have only been few studies of the effects of T. evansi infection on neuronal differentiation and brain plasticity. Here, we investigated the impact of the congenital T. evansi infection on brain development in mice. We collected telencephalon-derived neural progenitor cells (NPCs) from T. evansi uninfected and infected mice, and cultivated them into neurospheres. We found that T. evansi significantly decreased the number of cells during development of neurospheres. Analysis of neurosphere differentiation revealed that T. evansi infection significantly increased neural migration. We also observed that T. evansi promoted expression of glial fibrillary acidic protein (GFAP) in infected cells. These data suggest that congenital T. evansi infection may affect embryonic brain development.

Effects of resveratrol on the differentiation fate of neural progenitor cells of mouse embryos infected with Trypanosoma cruzi

Chagas disease (CD) affecting about 7 million people is caused by the flagellate protozoan Trypanosoma cruzi. The central nervous system (CNS) is an important site for T. cruzi persistence in the host during the chronic phase of infection, because the protozoan may pass the blood-brain barrier and may cause motor and cognitive neuronal damage. Thinking about avoiding or minimizing these negative effects, it is hypothesized that resveratrol (RSV), a component with several medicinal properties has beneficial effects on the CNS. The objective of this study was to investigate, whether T. cruzi infection interferes with neurogenesis and gliogenesis of embryos of infected mice females, and whether RSV would be able to avoid or minimize these changes caused by CD. RSV is a polyphenol found in grapes and widely studied for its neuroprotective and antioxidant properties. In addition, we investigated the role caused by the parasite during congenital infection and CNS development. Embryos and their brains were PCR-positive for T. cruzi. For this study, NPCs obtained from telencephalon of infected and uninfected embryos and were cultured in presence of resveratrol for forming neurospheres. The results demonstrated that the congenital transmission of T. cruzi influences CNS formation and neural fate, decreasing the number of neuroespheres and causing an elongation in the phases of the cell cycle. In addition, the parasite promoted an increase in neugliogenesis. Resveratrol was neuroprotective and prevented negative effects of the infection. Thus, we suggest the use of resveratrol as a therapeutic target for the treatment of neuroinflammation or as neuroprotective agent during Chagas disease, as it improves gliogenesis and restores neural migration.

Cordycepin (3'-deoxyadenosine) and pentostatin (deoxycoformycin) against Trypanosoma cruzi

The aim of this study was to evaluate in vitro the efficacy of cordycepin and pentostatin (alone or combined) against Trypanosoma cruzi, as well as the therapeutic efficiency of protocols of cordycepin and pentostatin combinations in mice experimentally infected with T. cruzi. In vitro, the cordycepin (3'-deoxyadenosine) and pentostatin (deoxycoformycin) exerted potent trypanocidal effect against T. cruzi (Colombian strain), similarly to benznidazole, which is the reference drug. For epimastigotes, the lethal dose of cordycepin capable of killing 50% (LD₅₀) and 20% (LD₂₀) of the parasites was 0.072 and 0.031 mg/mL, respectively and for trypomastigotes was 0.047 and 0.015 mg/mL, respectively. The combined use of cordycepin and pentostatin resulted in a LD₅₀ and LD₂₀ for epimastigotes of 0.068 and 0.027 mg/mL, respectively, as well as 0.056 and 0.018 mg/mL for trypomastigotes, respectively. In vivo, the combined use of cordycepin and pentostatin did not show the expected curative effect, however it was able to control the parasitema in the peak period. In summary, the combination of cordycepin and pentostatin showed no curative effect in mice infected by T. cruzi, despite the in vitro reduction of epimastigotes and trypomastigotes.

Nucleotide and nucleoside involvement in immunomodulation in experimental Chagas disease

The aim of this study was to evaluate whether Trypanosma cruzi infections cause alterations in the levels of seric purines, which could contribute to host immunomodulation. Twelve mice were divided into two groups identified as control (uninfected) and infected (T. cruzi) groups. The influence of the disease on seric purine levels was verified on day 20 post-infection (PI) by HPLC. Infected mice had circulating trypomastigotes during the experiment, as well as amastigote forms in the heart associated with inflammatory infiltrates. Increases on adenosine triphosphate (ATP), adenosine diphosphate (ADP), adenosine (ADO), inosine (INO), and uric acid (URIC) levels were observed in the infected animals, while the adenosine monophosphate (AMP) and xanthine (XAN) levels were reduced compared with mice of the control group, indicating a possible impairment on the purinergic system, and consequently, on the immune system during the clinical course of the disease. In summary, the T. cruzi infection alters the seric purine levels, and consequently, modulates the immune system.

Avian antibodies (IgY) against Trypanosoma cruzi: Purification and characterization studies

Trypanosoma cruzi is a flagellated protozoan belonging to the Trypanosomatidae family, the etiologic agent of Chagas disease. Currently, there is neither a licensed vaccine nor effective treatment, characterizing an unmet clinical need. The IgY refers to the egg yolk immunoglobulin (Y=yolk) and its production and use are subjects of many studies due to the diversity of its diagnostic and therapeutic applications. Several researchers have shown that the use of specific IgY may prevent and/or control infectious and parasitic diseases. Based on these evidences, the aim of this study was to immunize chickens with trypomastigotes of T. cruzi in order to produce highly effective and pure antibodies (IgY), as well as extract, characterize, quantify, and verify cytotoxic effects of IgY anti-T. cruzi. After the induction of IgY production by chickens, the eggs were collected and the IgY was extracted by method of precipitation of polyethylene glycol 6000. The IgY anti-T. cruzi characterization was performed using polyacrylamide gel electrophoresis (SDS-PAGE), western-blot and enzyme-linked immunosorbent assay (ELISA). Moreover, the cytotoxic or proliferative effects of IgY anti-T. cruzi was verified by MTT assay. The concentration of IgY in yolk was 8.41±1.47mg/mL. The characterization of IgY reveled bands of stained peptides with molecular weight between 75 and 50kDa and 37 and 25kDa. In the ELISA test was observed that there was antigen-antibody reaction throughout the sample period. The concentrations of 1, 5 and 10mg/mL of IgY anti-T. cruzi presented no cytotoxic of proliferative effects in mononuclear and VERO cells in vitro. The results indicated that T. cruzi is able to generate a high production of specific immunoglobulins in chickens, it did not cause damage to the cell membrane and no proliferative effect.

Antihyperglycemic, antioxidant activities of tucumã oil (Astrocaryum vulgare) in alloxan-induced diabetic mice, and identification of fatty acid profile by gas chromatograph: New natural source to treat hyperglycemia

The aim of the study was to investigate the effect of the oral administration of tucumã oil (Astrocaryum vulgare) on glucose and insulin levels, oxidative status, and pancreatic genotoxic parameters of alloxan-induced diabetic mice. The animals were divided into four groups (n = 6 each): control/water; control/tucumã oil; diabetic/water; diabetic/tucumã oil treated for 14 days with 5.0 mL kg^-1 via oral gavage. Gas chromatograph characterization demonstrated that oleic/elaidic fatty acid is the most abundant component present in this oil, followed by palmitic and stearic fatty acids. Our results demonstrated an increase (p < 0.05) in water and food intake, blood glucose, thiobarbituric acid reactive species (TBARS) levels, damage index, and frequency of damage; conversely body weight, insulin levels, catalase (CAT) and superoxide dismutase (SOD) activities, and cell viability were decreased in the diabetic/water group compared to the control/water group. The treatment with tucumã oil prevented these alterations in the diabetic/tucumã oil group compared to the diabetic/water group, and restored these parameters near to the control/water group. In summary, our findings demonstrated that treatment with tucumã oil causes a hypoglycemic effect improving insulin levels and antioxidant/oxidant status, and has a protector effect against pancreatic damage induced by oxidative stress in alloxan-induced diabetic mice.

Purinergic ecto-enzymes participate in the thromboregulation in acute in mice infection by Trypanosoma cruzi

Coagulation disorders have been described in Chagas disease with thrombocytopenia as an important event. Several mechanisms may be related to this pathogenesis, such as enzymes of the purinergic system, purine, and receptors involved in the regulation and modulation of physiological events related to hemostasis. Therefore, the aim of this study was to evaluate the activities of E-NTPDase, E-5'nucleotidase, and ecto-adenosine deaminase (E-ADA) in platelets of mice experimentally infected by Trypanosoma cruzi. Twelve female mice were used, divided into two groups (n = 6): uninfected and infected. Mice of infected group were intraperitoneally inoculated with 10⁴ trypomastigotes of T. cruzi (strain Y). On day 12 post-infection (PI), blood samples were collected for quantitation and separation of platelets. A significant reduction in the number of platelets of infected mice (P < 0.05) was observed. The activities of E-NTPDase (ATP and ADP substrates), E-5'nucleotidase, and E-ADA in platelets increased significantly (P < 0.05) in mice infected by T. cruzi compared with uninfected animals. A negative correlation (P < 0.01)was observed between the number of platelets and ATP hydrolysis (r = -0.64), and ADP hydrolysis (r = -0.69) by E-NTPDase. Therefore, there is a response from the purinergic system activating ecto-enzymes in platelets of mice T. cruzi infected, as a compensatory effect of thrombocytopenia.

Hypolipidemic effect of β-caryophyllene to treat hyperlipidemic rats

The aim of this study was to evaluate the effect of β-caryophyllene on hypercholesterolemia using a model of hyperlipidemia induced by Triton WR-1339 in rats, as well as its possible effect on hepatic antioxidant enzymes. Thus, total cholesterol, triglycerides, low-density lipoprotein (LDL) cholesterol, and high-density lipoprotein (HDL) cholesterol were measured in serum, while reactive oxygen species (ROS), thiobarbituric acid reactive substances (TBARS), hepatic 3-hydroxy-3-methylglutayl coenzyme A (HMG-CoA) reductase, superoxide dismutase (SOD), and catalase (CAT) activities were measured in the hepatic tissue. In addition, seric concentrations of β-caryophyllene were measured to perform correlation studies. Serum samples from hypercholesterolemic rats show higher (p < 0.05) levels of total cholesterol, triglycerides, and LDL cholesterol, and lower (p < 0.05) levels of HDL cholesterol compared to non-hypercholesterolemic rats. β-Caryophyllene treatment reduced (p < 0.05) the levels of total cholesterol, triglycerides and LDL cholesterol, similar to the reference drug simvastatin. However, HDL cholesterol levels did not increase with the treatment. β-Caryophyllene treatment was able to inhibit the HMG-CoA reductase activity, as well as to prevent the increase on ROS and TBARS levels, and ameliorate the antioxidant system. In summary, our findings demonstrated that β-caryophyllene has hypolipidemic effect via inhibition of the hepatic HMG-CoA reductase, like the standard drug simvastatin, and this inhibition suggests a possible mechanism of hypolipidemic action. Thus, our results indicate that β-caryophyllene can be used to treat dyslipidemic diseases because it exerts a similar effect as the reference drug, protecting the liver against lipid damage and improving the hepatic antioxidant defense system.

Memory deficit, toxic effects and activity of Na(+), K(+)-ATPase and NTPDase in brain of Wistar rats submitted to orally treatment with alpha-terpinene

The neurotoxic effects and activity of Na(+), K(+)-ATPase and NTPDase in Wistar rats after treatment with α-terpinene (daily oral administration of 0.5, 0.75 and 1.0mLkg(-1) for 10days) were examined. Results of the inhibitory avoidance task showed a memory deficit (p<0.05) in rats treated with all doses of α-terpinene. The evaluation of DNA damage in brain tissue revealed an increase (p<0.05) on frequency of damage and damage index in all concentrations. According to the cytotoxicity assay, doses of 0.5, 0.75 and 1.0mLkg(-1) increase the lactate dehydrogenase levels, and doses of 1.0mLkg(-1) also decrease (p<0.05) cell viability in brain cells. A decrease (p<0.05) on Na(+), K(+)-ATPase activity in brain tissue and on NTPDase activity in serum were observed in all concentrations of α-terpinene. These results suggest that the α-terpinene was cytotoxic and genotoxic to the brain cells by inducing loss of cell viability and DNA damage, as well as causing alterations in Na(+), K(+)-ATPase and NTPDase activity, what may contribute to the memory deficit of treated animals. Thus, α-terpinene cannot be consumed by the population at the doses studied.

Oxidative Stress in the Heart of Rats Infected with Trypanosoma evansi

This study was conducted to investigate the occurrence of oxidative stress in the heart tissue of rats infected with Trypanosoma evansi. Rats were divided into 2 groups (A and B) with 12 animals each, and further subdivided into 4 subgroups (A1 and A2, 6 animals/each; and B1 and B2, 6 animals/each). Animals in the groups B1 and B2 were subcutaneously inoculated with T. evansi. Thiobarbituric acid reactive substances (TBARS), superoxide dismutase activity (SOD), glutathione S-transferase activity (GST), reduced glutathione activity (GSH), and non-protein thiols (NPSH) in the heart tissue were evaluated. At day 5 and 15 post-infection (PI), an increase in the TBARS levels and a decrease in the SOD activity (P<0.05) were observed. GSH and GST activities were decreased in infected animals at day 15 PI (P<0.05). Considering the proper functioning of the heart, it is possible that the changes in the activity of these enzymes involved in the oxidative stress may be related, at least in part, in the pathophysiology of rats infected with T. evansi.

Relationship between DNA damage in liver, heart, spleen and total blood cells and disease pathogenesis of infected rats by Trypanosoma evansi

Trypanosoma evansi is an important pathogen that causes changes in nitric oxide (NO) levels and antioxidant enzymes, as well as oxidative stress. The present study evaluated the in vivo effect of T. evansi infection on frequency and index of DNA damage in liver, heart, spleen and total blood of rats. Twenty rats were assigned into two groups with ten rats each, being subdivided into four subgroups (A1 and A2, 5 animals/group; and B1 and B2, 5 animals/group). Rats in the subgroups A1 and A2 were used as control (uninfected) and animals in the subgroups B1 and B2 were inoculated with T. evansi (infected). NO in serum and the comet assay were used to measure DNA damage index (DI) and damage frequency (DF) in liver, heart, spleen and total blood of infected rats. Increased NO levels on days 3 and 9 post-infection (PI) was observed (P < 0.001). Also, it was verified an increase on DI and DF in the evaluated organs on days 3 and 9 PI (P < 0.001). Our data show that T. evansi infection causes genotoxicity due to the production of NO, causing not only the death of the protozoan, but also inducing DNA damage in the host.