Search

Placental malaria, characterized by sequestration of Plasmodium falciparum in the maternal placental blood space and associated inflammatory damage, contributes to poor birth outcomes and ~200,000 infant deaths annually. Specific mechanisms that contribute to placental damage and dysfunction during malaria are not completely understood. To investigate a potential role for oxidative stress, antioxidant genes and markers for oxidative damage were assessed by quantitative PCR and immunohistochemistry in Plasmodium chabaudi AS-infected pregnant mice. Widespread evidence of lipid peroxidation was observed and was associated with higher antioxidant gene expression in conceptuses of infected mice. To assess the extent to which this oxidative damage might contribute to poor birth outcomes and be amenable to therapeutic intervention, infected pregnant mice were treated with N -acetylcysteine, a free radical scavenger, or tempol, an intracellular superoxide dismutase mimetic. The results show that mice treated with N -acetylcysteine experienced malaria induced-pregnancy loss at the same rate as control animals and failed to mitigate placental oxidative damage. In contrast, tempol-treated mice exhibited subtle improvement in embryo survival at gestation day 12. Although lipid peroxidation was not consistently reduced in the placentas of these mice, it was inversely related to embryo viability. Moreover, reduced IFN-γ and CCL2 plasma levels in treated mice were associated with midgestational embryo viability. Thus, although oxidative stress is remarkable in placental malaria and its mitigation by antioxidant therapy may improve pregnancy outcomes, the underlying mechanistic basis and potential therapeutic strategies require additional investigation., Competing Interests: DISCLOSURES The authors have no financial conflicts of interest.

Helicobacter spp. are gram-negative, helically shaped bacteria that cause gastric and enterohepatic infections in mammalian species. Although Helicobacter infection frequently is implicated to interfere with reproductive success, few experimental data support these claims. We therefore retrospectively investigated the effect of Helicobacter infection on murine pregnancy outcome after the identification of endemic Helicobacter infection in an animal research facility. Multiplex conventional PCR analysis was used to characterize Helicobacter infection status in one inbred and 2 transgenic strains of mice in 2 self-contained rooms assigned to the same investigator. Outcomes of timed-mating experiments were compared among Helicobacter spp.-infected and uninfected mice of the same strain; Helicobacter infection was eradicated from the colony through fostering with uninfected dams. Although Helicobacter infection affected fecundity in only one strain of transgenic mouse, the total number of embryos per gravid uterus was significantly reduced in C57BL/6J mice that were infected with a single Helicobacter species, H. typhlonius. Helicobacter infection was also associated with a significant increase in the number of resorbing embryos per uterus and significant decreases in pregnancy-associated weight gain relative to uninfected mice in C57BL6/J mice and one transgenic strain. Helicobacter spp.-infected mice of all tested strains exhibited higher frequency of intrauterine hemorrhaging relative to uninfected mice. These results indicate that naturally-acquired Helicobacter infection not only reduces the productivity of a research animal breeding colony, but also negatively impacts embryo health. Despite these deleterious effects, these data suggest that colonies can be rederived to be Helicobacter-free by Cesarean section and fostering with uninfected dams. This paper provides the first evidence that H. typhlonius infection is sufficient to interfere with reproductive success and embryo health of C57BL/6J mice. Animal research facilities should therefore implement Helicobacter spp. surveillance and control practices to avoid confounding experimental results and to improve breeding colony efficiency.

Introduction: Plasmodium chabaudi AS-infection in pregnant A/J and C57BL/6J mice results in mid-gestational pregnancy loss. Although associated with increased systemic and placental pro-inflammatory responses and coagulopathy, the molecular mechanisms that underlie poor pregnancy outcomes in these mice are not yet fully understood. This study investigates the relationships between inflammation, apoptosis and malaria-induced pregnancy loss., Methods: Infection with P. chabaudi AS in early murine pregnancy and term human placental tissues from an endemic setting were assessed by histology, immunohistochemistry, TUNEL staining, real-time PCR, flow cytometry, western blot, and ELISA., Results: Quantitative PCR reveals accumulation of lymphocytes and monocytes and upregulation of chemokines that attract these cell types in malaria-exposed mid-gestational A/J conceptuses. Monocyte accumulation is confirmed by flow cytometry and placental immunohistochemistry. Concurrent with initiation of malaria-induced abortion, markers of apoptosis are evident in the junctional zone, but not the labyrinth, of A/J placentae. In contrast, mid-gestation conceptuses in infected C57BL/6J lack evidence for monocyte accumulation, exhibiting low or no in situ placental staining despite trophoblast immunoreactivity for the monokine, CCL2. Additionally, placental apoptosis is not consistently observed, and when evident, appears after malaria-induced abortion typically initiates. Similarly, trophoblast apoptosis in term human placental malaria is not observed. Of those studied, a sole common feature of malaria-induced abortion in A/J and C57BL/6J mice is elevation of plasma tumor necrosis factor., Discussion: Consistent with our previous observations, tumor necrosis factor is likely to be a central driver of malaria-induced pregnancy loss in both strains, but likely operates through mechanisms distinct from placental apoptosis in C57BL/6J mice., (Published by Elsevier Ltd.)

Background: Activation of the A2A adenosine receptor (A2AAR) decreases production of inflammatory cytokines, prevents C. difficile toxin A-induced enteritis and, in combination with antibiotics, increases survival from sepsis in mice. We investigated whether A2AAR activation improves and A2AAR deletion worsens outcomes in a murine model of C. difficile (strain VPI10463) infection (CDI)., Methods: C57BL/6 mice were pretreated with an antibiotic cocktail prior to infection and then treated with vancomycin with or without an A2AAR agonist. A2AAR-/- and littermate wild-type (WT) mice were similarly infected, and IFNγ and TNFα were measured at peak of and recovery from infection., Results: Infected, untreated mice rapidly lost weight, developed diarrhea, and had mortality rates of 50-60%. Infected mice treated with vancomycin had less weight loss and diarrhea during antibiotic treatment but mortality increased to near 100% after discontinuation of antibiotics. Infected mice treated with both vancomycin and an A2AAR agonist, either ATL370 or ATL1222, had minimal weight loss and better long-term survival than mice treated with vancomycin alone. A2AAR KO mice were more susceptible than WT mice to death from CDI. Increases in cecal IFNγ and blood TNFα were pronounced in the absence of A2AARs., Conclusion: In a murine model of CDI, vancomycin treatment resulted in reduced weight loss and diarrhea during acute infection, but high recurrence and late-onset death, with overall mortality being worse than untreated infected controls. The administration of vancomycin plus an A2AAR agonist reduced inflammation and improved survival rates, suggesting a possible benefit of A2AAR agonists in the management of CDI to prevent recurrent disease.