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

Neurodevelopmental Outcomes in Children Vertically Exposed to Chikungunya Virus: A Two Years Follow-up Study

OBJECTIVES

To monitor by the first 24 months of life, children born to mothers with laboratory evidence of chikungunya virus (CHIKV) infection during pregnancy or up to 8 weeks before it, and to describe abnormalities in head circumference (HC), auditory and ophthalmological assessments and neuroimaging tests during the follow-up period.

METHOD

This is a observational, descriptive, longitudinal and prospective study of children born to mothers who had a rash and a positive test for CHIKV during pregnancy or up to 8 weeks before it. They were admitted between November 2015 and May 2019 in the outpatient multidisciplinary clinic to investigate acute exanthematous disease. The exposed children were followed up by a multidisciplinary team and underwent periodic measurements of the HC. The Denver II test was applied, in addition to transfontanellar ultrasound (TU) to evaluate neurodevelopmental outcomes during the study period. Ophthalmological and auditory examinations, echocardiography and laboratory tests were also included.

RESULTS

We included in the study 27 children vertically exposed to CHIKV. All children had a negative polymerase chain reaction test for the virus collected at the first outpatient visit (mean age of 16.8 days and standard deviation of 8 days). No clinical condition compatible with congenital infection at birth was reported. A change in HC characterized by macrocephaly and mild global delay development was observed in a 1-year-old child whose mother was infected in the peripartum, but with normal TU. Changes in the TU were observed in 2 other children with nonspecific subependymal cystic malformation that was not evident by the cranial computed tomography. The other children monitored showed normal results in the Denver II test, in the HC and TU. No changes were identified on ocular ophthalmoscopy or auditory brainstem response test. Two children had an increase in serum ferritin levels during the first year of life, with the others' inflammatory disease markers normal.

CONCLUSIONS

Our study added knowledge about the neurodevelopment of children exposed to CHIKV during pregnancy by a longitudinal and prospective follow-up, throughout their first 24 months of life. We did not observe a negative impact of exposure to the virus on the neurological examination, global developmental test or measurements of the HC of these children.

ÁP, Alvarez AM. From gut to placenta: understanding how the maternal microbiome models life-long conditions

The microbiome -defined as the microbiota (bacteria, archaea, lower and higher eukaryotes), their genomes, and the surrounding environmental conditions- has a well-described range of physiological functions. Thus, an imbalance of the microbiota composition -dysbiosis- has been associated with pregnancy complications or adverse fetal outcomes. Although there is controversy about the existence or absence of a microbiome in the placenta and fetus during healthy pregnancy, it is known that gut microbiota can produce bioactive metabolites that can enter the maternal circulation and may be actively or passively transferred through the placenta. Furthermore, the evidence suggests that such metabolites have some effect on the fetus. Since the microbiome can influence the epigenome, and modifications of the epigenome could be responsible for fetal programming, it can be experimentally supported that the maternal microbiome and its metabolites could be involved in fetal programming. The developmental origin of health and disease (DOHaD) approach looks to understand how exposure to environmental factors during periods of high plasticity in the early stages of life (e.g., gestational period) influences the program for disease risk in the progeny. Therefore, according to the DOHaD approach, the influence of maternal microbiota in disease development must be explored. Here, we described some of the diseases of adulthood that could be related to alterations in the maternal microbiota. In summary, this review aims to highlight the influence of maternal microbiota on both fetal development and postnatal life, suggesting that dysbiosis on this microbiota could be related to adulthood morbidity.

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

BACKGROUND

Dengue virus (DENV) infection during pregnancy increases the risk of adverse fetal outcomes, which has become a new clinical challenge. However, the underlying mechanism remains unknown.

METHODS

The effect of DENV-2 infection on fetuses was investigated using pregnant interferon α/β receptor-deficient (Ifnar1-/-) mice. The histopathological changes in the placentas were analyzed by morphological techniques. A mouse inflammation array was used to detect the cytokine and chemokine profiles in the serum and placenta. The infiltration characteristics of inflammatory cells in the placentas were evaluated by single-cell RNA sequencing.

FINDINGS

Fetal growth restriction observed in DENV-2 infection was mainly caused by the destruction of the placental vasculature rather than direct damage from the virus in our mouse model. After infection, neutrophil infiltration into the placenta disrupts the expression profile of matrix metalloproteinases, which leads to placental dysvascularization and insufficiency. Notably, similar histopathological changes were observed in the placentas from DENV-infected puerperae.

INTERPRETATION

Neutrophils play key roles in placental histopathological damage during DENV infection, which indicates that interfering with aberrant neutrophil infiltration into the placenta may be an important therapeutic target for adverse pregnancy outcomes in DENV infection.

FUNDING

The National Key Research and Development Plans of China (2021YFC2300200-02 to J.A., 2019YFC0121905 to Q.Z.C.), the National Natural Science Foundation of China (NSFC) (U1902210 and 81972979 to J. A., 81902048 to Z. Y. S., and 82172266 to P.G.W.), and the Support Project of High-level Teachers in Beijing Municipal Universities in the Period of 13th Five-year Plan, China (IDHT20190510 to J. A.).

The Placental Function Beyond Pregnancy: Insights from Latin America

Currently, more than 100,000 papers had been published studying the placenta in both physiological and pathological contexts. However, relevant health conditions affecting placental function, mostly found in low-income countries, should be evaluated deeper. This review will raise some - of what we think necessary - points of discussion regarding challenging topics not fully understood, including the paternal versus maternal contribution on placental genes imprinting, placenta-brain communication, and some environmental conditions affecting the placenta. The discussions are parts of an international effort to fulfil some gaps observed in this area, and Latin-American research groups currently evaluate that.