The limited knowledge of placental damage due to neglected infections: ongoing problems in Latin America

Abstract

The placenta works as a selective barrier, protecting the fetus from potential infections that may affect the maternal organism during pregnancy. In this review, we will discuss several challenging infections that are common within Latin American countries and that may affect the maternal-fetal interface and pose risks to fetal development. Specifically, we will focus on emerging infectious diseases including the arboviruses, malaria, leishmaniasis, and the bacterial foodborne disease caused by Shiga toxinproducing Escherichia coli. We will also highlight some topics of interest currently being studied by research groups that comprise an international effort aimed at filling the knowledge gaps in this field. These topics address the relationship between exposure to microorganisms and placental abnormalities, congenital anomalies, and complications of pregnancy.

The Autism Spectrum Disorder and Its Possible Origins in Pregnancy

“…Viruses and fungi are also associated with the development of chorioamnionitis, such as CMV, enterovirus, human papillomavirus (HPV), Zika virus and other arboviruses, and Candida spp. [ 162 ].…”

Neutrophil infiltration leads to fetal growth restriction by impairing the placental vasculature in DENV-infected pregnant mice

“…Recently, an increasing number of cases of DENV infection during pregnancy have been reported and are definitely associated with increased morbidity and mortality in both mothers and fetuses. 2 , 3 , 4 Meta-analysis showed that preterm birth and low birth weight are the most common adverse pregnancy outcomes associated with maternal DENV infection. 5 , 6 Further histopathological examinations of placentas collected at delivery from maternal DENV infection have shown hypoxic lesions with villous stromal edema and infarcted and preinfarcted areas in 19 of 24 cases, including eight from mothers who did not report overt shock syndrome.…”

Placental Malaria: Histological Findings and Immune Cell Infiltrates in Submicroscopic Infections

“…In pregnant women, cell-mediated immunity is modulated to promote the development of the placenta and its implantation in the maternal endometrium. But this halt in cell-mediated immunity makes pregnant women more susceptible to intracellular pathogens [25]. However, in malaria-infected pregnant women, an increase in cell-mediated immunity has been observed in the local placental environment with elevated levels of pro-in ammatory cytokines, such as IFN-γ, IL-2, and TNF-α [25][26][27].…”

“…But this halt in cell-mediated immunity makes pregnant women more susceptible to intracellular pathogens [25]. However, in malaria-infected pregnant women, an increase in cell-mediated immunity has been observed in the local placental environment with elevated levels of pro-in ammatory cytokines, such as IFN-γ, IL-2, and TNF-α [25][26][27]. These cytokine levels correlate with increased Hofbauer cell density, parasite density, and malaria pigments in the placenta.…”

“…The chemokines help to recruit macrophages, cytotoxic T cells, B cells, and granulocytes in the placenta and contribute to the pathologies of placental malaria. There is excessive sequestration of parasitized red blood cells and leukocytes in the IVS of placenta and formation of perivillous brin clots during malarial infection, which interfere with blood ow across the placenta thus restricting nutrients to the fetus [25,28,29]. Submicroscopic infections are common in pregnant women [30].…”