Is the adaptive immune response in murine Trypanosoma cruzi infection influenced by zinc supplementation?

Chagas disease afflicts 7 to 8 million people worldwide and congenital Chagas' disease usually leads to changes in the maternal environment, culminating in fetal adaptations. Several articles have described the importance of micronutrients on pregnancy, which is sensitive to infections. In Trypanosoma cruzi endemic regions, the Chagas disease is aggravated by the lack of micronutrients in an average diet, to which pregnant women are more susceptible.

Melatonin: Antioxidant and modulatory properties in age-related changes during Trypanosoma cruzi infection.

The purpose of this study was to investigate the effects of melatonin on selected biomarkers of innate and humoral immune response as well as the antioxidant/oxidant status (superoxide dismutase-SOD and reduced glutathione levels (GSH) to understand whether age-related changes would influence the development of acute Trypanosoma cruzi (T. cruzi) infection. Young- (5 weeks) and middle-aged (18 months) Wistar rats were orally treated with melatonin (gavage) (05 mg/kg/day), 9 days after infection.

Ageing is not associated with an altered immune response during Trypanosoma cruzi infection: Ageing and Trypanosoma cruzi infection.

The aims of this work were to evaluate the influence of ageing on the magnitude of the immune response in male Wistar rats infected with the Y strain of Trypanosoma cruzi (T. cruzi). Infected young animals displayed enhanced CD4 T cells as compared to uninfected counterparts.

Interleukin-17, oxidative stress, and inflammation: role of melatonin during Trypanosoma cruzi infection.

Although the exact etiology of Chagas' disease remains unknown, the inflammatory process and oxidative stress are believed to be the main contributors to the dysfunction and pathogenesis during chronic Trypanosoma cruzi infection. Our hypothesis is that melatonin administered for 2 months daily could modulate the oxidative stress and the inflammatory response during the chronic infection. Flow cytometric analysis of macrophages and antigen-presenting cells (APC), expression of RT1B as well as LFA-1 and MCP-1 in CD4(+) and CD8(+) T cells and levels of interleukin-17A were assessed.

Immunoregulatory actions of melatonin and zinc during chronic Trypanosoma cruzi infection.

After one century of the discovery of Chagas' disease and the development of an efficient drug with amplitude of actions both in the acute and chronic phase is still a challenge. Alternative immune modulators have been exhaustively used. For that purpose, melatonin and zinc were administered during chronic Trypanosoma cruzi-infected Wistar rats and several endpoints were assessed.

Immunomodulatory properties and anti-apoptotic effects of zinc and melatonin in an experimental model of chronic Chagas disease.

The immunomodulatory effects of melatonin and zinc during chronic experimental Chagas' disease were studied. Early and late apoptosis by Annexin V-propidium iodide staining were evaluated. The expression of CD28, CD80, CD86, CD45RA and CD4(+)T and CD8(+)T cells were also evaluated by flow cytometry analysis.

In vivo activity of ursolic and oleanolic acids during the acute phase of Trypanosoma cruzi infection.

Reduction in the parasitemic levels of the Y strain of Trypanosoma cruzi in mice treated with oral or intraperitoneal ursolic (UA) and oleanolic (OA) acids was evaluated during the acute phase of Chagas' disease. Oral administration of UA and OA (50mg/kg/day) provided the most significant reduction in the parasitemic peak, while intraperitoneal administration of UA and OA did not significantly affect the biological activity of the Y strain of T. cruzi.

Does orchiectomy enhance the immune-stimulatory effects of melatonin during experimental Chagas' disease?

Melatonin has been reported to play a fundamental role in T-cell immunoregulation. Control of Trypanosoma cruzi parasitism during the acute phase of infection is considered to be critically dependent on direct macrophage activation by cytokines. The aim of this work was to evaluate the influence of exogenous melatonin treatment and the influences exerted by sexual hormones during the acute phase of the experimental Chagas' disease in rats.

Melatonin and zinc treatment: distinctive modulation of cytokine production in chronic experimental Trypanosoma cruzi infection.

Melatonin by exhibiting antioxidant, anti-aging, and immunomodulatory properties favorably modulate the immune function, protecting the hosts from several infectious diseases. Zinc is an essential trace element important for the efficiency of the immune system in reason of its widespread role in the activity of enzymes, transcription factors and cytokines. The etiology of Chagas' disease, caused by a protozoan parasite Trypanosoma cruzi, has been the focus of considerable discussion, although chronic phase still remains not fully understood.

Prolactin: does it exert an up-modulation of the immune response in Trypanosoma cruzi-infected rats?

During the course of infection by Trypanosoma cruzi, the host immune system is involved in distinct, complex interactions with the endocrine system, and prolactin (PRL) is one of several hormones involved in immunoregulation. Although intensive studies attempting to understand the mechanisms that underlie Chagas' disease have been undertaken, there are still some pieces missing from this complex puzzle. Because data are scarce concerning the role of PRL involvement in Chagas' disease and taking into account the existence of crosstalk between neuroendocrine hormones and the immune system, the current study evaluates a possible up-regulation of the cellular immune response triggered by PRL in T.

Prior and concomitant dehydroepiandrosterone treatment affects immunologic response of cultured macrophages infected with Trypanosoma cruzi in vitro?

DHEA, a steroid hormone synthesized from cholesterol by cells of the adrenal cortex, plays an essential role in enhancing the host's resistance to different experimental infections. Receptors for this hormone can be found in distinct immune cells (especially macrophages) that are known to be the first line defense against Trypanosoma cruzi infection. These cells operate through an indirect pathway releasing nitric oxide (NO) and cytokines such TNF-α and IL-12 which in turn trigger an enhancement of natural killer cells and lymphocytes which finally secrete pro and anti-inflammatory cytokines.

DHEA and testosterone therapies in Trypanosoma cruzi-infected rats are associated with thymic changes.

The ability of the gonadal hormones to influence diverse immunological functions during the course of several infections has been extensively studied in the latest decades. Testosterone has a suppressive effect on immune response of vertebrates and increases susceptibility toward numerous parasitic diseases. Dehydroepiandrosterone is an abundant steroid hormone secreted by the human adrenal cortex and it is considered potent immune-activator.

New method for quantification of Trypanosoma cruzi in animal's tissue in the chronic phase of experimental Chagas' disease.

We developed a new method for the quantification of parasites in tissue. Trypanosoma cruzi strain CL parasites were genetically engineered to express the Escherichia coli beta-galactosidase gene, lacZ and this enzyme is able to catalyze a colorimetric reaction with chlorophenol red beta-D: galactopyranoside (CPRG) as the substrate. The animals were infected with clone CL Brener strain B5 of T.

Effects of dehydroepiandrosterone-sulfate (DHEA-S) and benznidazole treatments during acute infection of two different Trypanosoma cruzi strains.

A significant role for hormones in regulating the balance of Th1- and Th2-associated cytokines with a role in modulating diseases has been accumulating. Previously, we reported that dehydroepiandrosterone (DHEA), the most abundant steroid hormone synthesized by the adrenal cortex, markedly reduced the blood and tissue parasites in experimentally Trypanosoma cruzi-infected rats. Based on these findings, the main purpose of this study was to investigate the effect of dehydroepiandrosterone-sulfate ester (DHEA-S) therapy alone or in combination with benznidazole (BNZ) (recommended in Brazil for the treatment of T.

Trypanocidal activity and acute toxicity assessment of triterpene acids.

The present study evaluates the in vitro and in vivo trypanocidal activity of ursolic acid and oleanolic acid against the Bolivia strain of Trypanosoma cruzi. Their acute toxicity is also assessed on the basis of median lethal dose (DL50) determination and quantification of biochemical parameters. Ursolic acid is the most active compound in vitro, furnishing IC50 of 25.

Growth hormones therapy in immune response against Trypanosoma cruzi.

Growth hormone (GH) is an important hypophyseal hormone that is primarily involved in body growth and metabolism. In mammals, control of Trypanosoma cruzi parasitism during the acute phase of infection is considered to be critically dependent on direct macrophage activation by cytokines. To explore the possibility that GH might be effective in the treatment of Chagas' disease, we investigated its effects on the course of T.

Trypanosoma cruzi: do different sylvatic strains trigger distinct immune responses?

Strains of Trypanosoma cruzi are multiclonal populations that can be classified in groups or genotypes, differing in pathogenicity, virulence, and histotropism. In this experiment the distinct behavior of two strains of T. cruzi, MORC-1 and MORC-2, was documented.

Immunomodulatory effects of zinc and DHEA on the Th-1 immune response in rats infected with Trypanosoma cruzi.

Chagas' disease is considered the sixth most important neglected tropical disease worldwide. Considerable knowledge has been accumulated concerning the role of zinc on cellular immunity. The steroid hormone dehydroepiandrosterone (DHEA) is also known to modulate the immune system.

Trypanosoma cruzi: dehydroepiandrosterone (DHEA) and immune response during the chronic phase of the experimental Chagas' disease.

Dehydroepiandrosterone (DHEA) has long been considered as a precursor for many steroid hormones. It also enhances the immune responses against a wide range of viral, bacterial, and parasitic pathogens. The aims of this work were to evaluate the influences of exogenous DHEA treatment on Wistar rats infected with the Y strain of Trypanosoma cruzi during the acute and its influence on the chronic phase of infection.

Trypanosoma cruzi: The effects of zinc supplementation in the immune response during the course of experimental disease.

Zinc is an essential nutritional component required for normal development and maintenance of immune functions. The possible effects of zinc in upregulating the host immune response during the acute and chronic phases of experimental Chagas' disease were evaluated. In young, infected and Zn-supplemented animals, higher concentrations of IFN-gamma and NO were observed.

Effects of repetitive stress during the acute phase of Trypanosoma cruzi infection on chronic Chagas' disease in rats.

The effect of repetitive stress during acute infection with Trypanosoma cruzi (T. cruzi) on the chronic phase of ensuing Chagas' disease was the focus of this investigation. The aim of this study was to evaluate in Wistar rats the influence of repetitive stress during the acute phase of infection (7 days) with the Y strain of T.

Trypanosoma cruzi: orchiectomy and dehydroepiandrosterone therapy in infected rats.

The ability of gonadal hormones to influence and induce diverse immunological functions during the course of a number of parasitic infections has been extensively studied in the latest decades. Dehydroepiandrosterone and its sulfate are the most abundant steroid hormones secreted by the human adrenal cortex and are considered potent immune-activators. The effects of orchiectomy on the course of Trypanosoma cruzi infection in rats, treated and untreated with DHEA were examined, by comparing blood and cardiac parasitism, macrophage numbers, nitric oxide and IFN-gamma levels.

Trypanosoma cruzi: effects of adrenalectomy during the acute phase of experimental infection.

Glucocorticoid hormones have been implicated as an important modulator of Trypanosoma cruzi pathogenesis. Since adrenal steroid hormones play a fundamental role in modulating the immune response, we hypothesized that adrenalectomy affect the course of the experimental T. cruzi infection.

Does cyclophosphamide play a protective role against neuronal loss in chronic T. cruzi infection?

In this study, we verified the possible role of cyclophosphamide (CY) in protecting or not against neuronal losses in young and aged male Calomys callosus chronically infected with the MORC-1 strain of Trypanosoma cruzi through numerical quantification of neurons from the myenteric plexus of the colon and quantification of nitric-oxide concentration (NO) during the acute and chronic phase of infection. For this purpose, groups of young C. callosus were infected with the MORC-1 strain of T.

Trypanosoma cruzi: effects of social stress in Calomys callosus a natural reservoir of infection.

Social environment can represent a major source of stress affecting cortisol and/or corticosterone levels, thereby altering the immune response. We have investigated the effects of social isolation on the development of Trypanosoma cruzi infection in female Calomys callosus, a natural reservoir of this protozoan parasite. Animals were divided in groups of five animals each.