Mammalian placental explants: A tool for studying host-parasite interactions and placental biology.

The placenta plays a critical role in host-pathogen interactions. Thus, ex vivo infection of mammalian placental explants is an excellent and simple method to study the mechanisms of cellular and tissue invasion by different pathogens in different mammalian species. These explants can be maintained in culture for several days, preserving the tissue architecture and resembling in-utero conditions under more physiological conditions than their isolated counterparts in isolated cell culture models.

Ghrelin misbalance affects mice embryo implantation and pregnancy success by uterine immune dysregulation and nitrosative stress.

Introduction: In a previous study we found that ghrelin (Ghrl) misbalance during the peri-implantation period significantly impaired fetus development. In this study we aimed to evaluate the putative mechanisms underlying these effects, including embryo implantation success, uterine nitric oxide synthase (NOS) activity, nitric oxide synthesis and the inflammatory/immune uterine profile.

Methods: Ghrelin misbalance was induced by injecting 4nmol/animal/day of Ghrl (hyperghrelinemia) or 6nmol/animal/day of a Ghrl antagonist (Ant: (D-Lys3)GHRP-6) from day 3 to 8 of pregnancy.

Pro-inflammatory cytokines are modified during the multiplication of Trypanosoma cruzi within the placental chorionic villi and are associated with the level of infection via the signaling pathway NF-κB.

Problem: Congenital Trypanosoma cruzi (T. cruzi) infection has been associated with changes in the levels of TNF-α and IFN-γ during the pregnancy. Therefore, we propose to study the participation and dynamics of proinflammatory cytokines in the infection process of placental explants infected by T.

Chagas disease affects the human placental barrier's turnover dynamics during pregnancy.

Background: Trypanosoma cruzi crosses the placental barrier and produces the congenital transmission of Chagas disease (CD). Structural alterations of the chorionic villi by this parasite have been described in vitro, but little is known about trophoblast turnover in placentas from women with CD.

Objective: To analyze the proliferation and fusion processes in placentas from women with CD.

NLRP3 Inflammasome and Caspase-1/11 Pathway Orchestrate Different Outcomes in the Host Protection Against Acute Infection.

Infection with protozoan parasite results in activation of nucleotide-binding domain and leucine-rich repeat containing receptors (NLRs). NLR activation leads to inflammasome formation, the activation of caspase-1, and the subsequent cleavage of IL-1β and IL-18. Considering that inflammasome activation and IL-1β induction by macrophages are key players for an appropriate T cell response, we investigated the relevance of NLR pyrin domain-containing 3 (NLRP3) and caspase-1/11 to elucidate their roles in the induction of different T cell phenotypes and the relationship with parasite load and hepatic inflammation during Tulahuen strain acute infection.

Nitric oxide synthase and oxidative-nitrosative stress play a key role in placental infection by Trypanosoma cruzi.

Problem: The innate immune response of the placenta may participate in the congenital transmission of Chagas disease through releasing reactive oxygen and nitrogen intermediates.

Method Of Study: Placental explants were cultured with 1 × 10 and 1 × 10 trypomastigotes of Tulahuen and Lucky strains and controls without parasites, and with the addition of nitric oxide synthase inhibitor Nω-Nitro-l-arginine methyl ester (l-NAME) and N-acetyl cysteine (NAC) as the reactive oxygen species (ROS) scavenger. Detachment of the syncytiotrophoblast (STB) was examined by histological analysis, and the nitric oxide synthase, endothelial (eNOS), and nitrotyrosine expressions were analyzed by immunohistochemistry, as well as the human chorionic gonadotrophin (hCG) levels in the culture supernatant through ELISA assays.

3-Hydroxykynurenine, a Tryptophan Metabolite Generated during the Infection, Is Active Against .

The antiparasitic activity of 3-hydroxykynurenine (3-HK), one of the major tryptophan catabolites of the kynurenine pathway, against both evolutive forms that are important for human infection, trypomastigotes (Tps) and amastigotes (Am), possible targets in the parasite and the drug toxicity to mammalian cells have been investigated. 3-HK showed a potent activity against Am with IC values in the micromolar concentration range, while the IC values to cause Tps death was ∼6000-times higher, indicating that the replicative form present in the vertebrate hosts is much more susceptible to 3-HK than bloodstream Tps. In addition, 3-HK showed activity against Tps and Am, at concentrations that did not exhibit toxicity to mammalian cells.

Effect of arsenite on nitrosative stress in human breast cancer cells and its modulation by flavonoids.

Arsenic (As) is used in the treatment of leukemia and breast cancer due to its oxidative cytotoxic action. However, it is also toxic to normal cells. One proposed anticancer mechanism induced by As might be nitrosative stress (NS).

Trypanosoma cruzi infectivity assessment in "in vitro" culture systems by automated cell counting.

Chagas disease is an endemic, neglected tropical disease in Latin America that is caused by the protozoan parasite Trypanosoma cruzi. In vitro models constitute the first experimental approach to study the physiopathology of the disease and to assay potential new trypanocidal agents. Here, we report and describe clearly the use of commercial software (MATLAB(®)) to quantify T.

3-Hydroxy kynurenine treatment controls T. cruzi replication and the inflammatory pathology preventing the clinical symptoms of chronic Chagas disease.

Background: 3-Hydroxy Kynurenine (3-HK) administration during the acute phase of Trypanosoma. cruzi infection decreases the parasitemia of lethally infected mice and improves their survival. However, due to the fact that the treatment with 3-HK is unable to eradicate the parasite, together with the known proapoptotic and immunoregulatory properties of 3-HK and their downstream catabolites, it is possible that the 3-HK treatment is effective during the acute phase of the infection by controlling the parasite replication, but at the same time suppressed the protective T cell response before pathogen clearance worsening the chronic phase of the infection.

Indoleamine 2,3-dioxigenase (IDO) is critical for host resistance against Trypanosoma cruzi.

Indoleamine 2,3-dioxygenase (IDO) is an inflammatory cytokine-inducible rate-limiting enzyme of the tryptophan (Trp) catabolism, which is involved in the inhibition of intracellular pathogen replication as well as in immunomodulation. Here we demonstrated the effect of IDO-dependent Trp catabolism on Trypanosoma cruzi resistance to acute infection. Infection with T.

Placental infection by two subpopulations of Trypanosoma cruzi is conditioned by differential survival of the parasite in a deleterious placental medium and not by tissue reproduction.

Chagas disease is caused by Trypanosoma cruzi, which can be transmitted to the fetus via the transplacental route. Factors that may be involved in transplacental transmission include parasite strain and placental immunological competence. The aim of this work was to compare the biological differences between two subpopulations of T.