The Placenta as a Research Biospecimen

Sex-specific association between placental inflammatory cytokine mRNA expression and preschoolers' behavioral development: The Ma'anshan birth cohort study

BACKGROUND

Placental inflammation may contribute to brain abnormalities and childhood neuropsychiatric disorders, but limited knowledge is available on the association of placental inflammatory cytokine levels and offspring's behavioral development. This study aimed to examine the sex-specific association between placental inflammatory cytokine mRNA expression and preschoolers' behavioral development.

METHODS

3474 pregnant women were recruited as the initial study population in the Ma'anshan birth cohort (MABC) study. Placentas (n = 2519) were collected during childbirth, and the mRNA expression of IL-8, IL-1β, CRP, TNF-α, IL-6, IL-10, and IL-4 was assessed. The Child Behavior Checklist 1.5-5 (CBCL 1.5-5) was used to assess children's behavioral development at 4 years old. A T-score ≥ 60 on summary scales or a score ≥ 65 on syndrome scales was regarded as the borderline clinical range. Multiple linear regression models and binary logistic regression models were applied to explore the sex-specific associations between placental inflammatory cytokines mRNA transcript levels and preschoolers' behavioral development.

RESULTS

Sex-specific associations between placental inflammatory cytokines mRNA expression and preschoolers' behavioral development were observed. There was a positive association between IL-8 and CBCL scores for boys on anxious/depressed problems, aggressive behaviors, externalizing problems and total problems. Logistic regression models showed that high levels of IL-8 were associated with a higher risk of girls' emotionally reactive problems and sleep problems compared to low/medium levels. High TNF-α was correlated with increased sleep problem scores in boys, and medium TNF-α (vs. low levels) was associated with an increased risk of girls' externalizing problems. Medium levels of CRP, IL-1β, and IL-6 were found to be associated with a decreased risk of girls' behavioral problems compared to low/high levels. For anti-inflammatory cytokines, medium IL-10 and IL-4 (vs. low levels) were observed to be associated with a lower risk of internalizing problems in boys and externalizing problems in girls, respectively. High IL-10 was correlated with decreased attention problem scores in boys.

CONCLUSION

This study indicates that placental inflammatory cytokine mRNA expression of IL-8, CRP, TNF-α, IL-1β, IL-4 and IL-10 may be associated with preschoolers' behavioral development in a sex-specific manner.

Higher concentration of selenium in placental tissues is associated with reduced risk for orofacial clefts

BACKGROUND & AIMS

Growing evidence suggests that essential trace element imbalance during pregnancy may contribute to fetal malformations, but the role of essential trace elements in the occurrence of orofacial clefts (OFCs) is unknown. We aimed to examine the association between concentrations of zinc (Zn), manganese (Mn), selenium (Se), cobalt (Co), molybdenum (Mo), and nickel (Ni) in placental tissues and the risk for OFCs in offspring in a rural population in northern China with a high prevalence of OFCs.

METHODS

The case-control study subjects were 103 OFC infants and 206 non-malformed infants. The concentrations of selected trace elements in placental tissues were determined using inductively coupled plasma-mass spectrometry. Sociodemographic information was collected from the mothers through face-to-face interviews using a structured questionnaire. The risk for OFCs in association with higher concentrations of the trace elements was estimated using the odds ratio (OR) with its 95% confidence interval (95% CI).

RESULTS

The placental median concentrations of Se and Ni were significantly lower, but those of Mo were significantly higher in OFC cases than in controls (all P < 0.05). A Se concentration above the median of all subjects was associated with a 58% reduced risk for OFCs (adjusted OR 0.42, 95% CI 0.23, 0.77) after adjusting for potential confounding factors. The risk for OFCs decreased with increases in placental Se concentrations, with adjusted ORs of 0.45 (95% CI 0.22, 0.92) for the second tertile and 0.22 (95% CI 0.10, 0.49) for the top tertile of Se concentration, with the lowest tertile concentration as the referent (P_trend < 0.001). No association was observed between placental Zn, Mn, Co, Mo, or Ni concentration and risk for OFC.

CONCLUSIONS

The concentration of Se in placental tissues was dose-dependently associated with decreased risk for OFCs in offspring. This finding suggests that maternal Se intake during pregnancy may protect against OFCs in offspring.

Air pollution and the fetal origin of disease: A systematic review of the molecular signatures of air pollution exposure in human placenta

BACKGROUND

Fetal development is a crucial window of susceptibility in which exposure-related alterations can be induced on the molecular level, leading to potential changes in metabolism and development. The placenta serves as a gatekeeper between mother and fetus, and is in contact with environmental stressors throughout pregnancy. This makes the placenta as a temporary organ an informative non-invasive matrix suitable to investigate omics-related aberrations in association with in utero exposures such as ambient air pollution.

OBJECTIVES

To summarize and discuss the current evidence and define the gaps of knowledge concerning human placental -omics markers in association with prenatal exposure to ambient air pollution.

METHODS

Two investigators independently searched the PubMed, ScienceDirect, and Scopus databases to identify all studies published until January 2017 with an emphasis on epidemiological research on prenatal exposure to ambient air pollution and the effect on placental -omics signatures.

RESULTS

From the initial 386 articles, 25 were retained following an a priori set inclusion and exclusion criteria. We identified eleven studies on the genome, two on the transcriptome, five on the epigenome, five on the proteome category, one study with both genomic and proteomic topics, and one study with both genomic and transcriptomic topics. Six studies discussed the triple relationship between exposure to air pollution during pregnancy, the associated placental -omics marker(s), and the potential effect on disease development later in life. So far, no metabolomic or exposomic data discussing associations between the placenta and prenatal exposure to air pollution have been published.

CONCLUSIONS

Integration of placental biomarkers in an environmental epidemiological context enables researchers to address fundamental questions essential in unraveling the fetal origin of disease and helps to better define the pregnancy exposome of air pollution.

Pilot study of placental tissue collection, processing, and measurement procedures for large scale assessment of placental inflammation

Background

Placental dysfunction is related to many pregnancy complications, but collecting placental specimens for investigation in large scale epidemiologic studies is often infeasible. Standard procedures involving immediate collection after birth and snap freezing are often cost prohibitive. We aimed to collect pilot data regarding the feasibility and precision of a simpler approach, the collection of tissue samples following 24 hours of refrigeration of whole placentae at 4°C, as compared to the “gold standard” of snap freezing excised tissue within 40 minutes of delivery for the assessment of inflammatory cytokines.

Methods

Placentae were collected from 12 women after delivering live-born singleton babies via uncomplicated vaginal delivery. Two placentae were utilized to establish laboratory tissue processing and assay protocols. The other 10 placentae were utilized in a comparison of three tissue collection conditions. Specifically, key inflammatory cytokines were measured in 3 sections, representing three collection conditions. Sections 1 (full thickness) and 2 (excised prior to freezing) were obtained within 40 minutes of delivery and snap frozen in liquid nitrogen, and section 3 (full thickness) was obtained after refrigerating the placenta at 4°C for 24 hours.

Results

IL-6, IL-10, and IL-8 all had comparable concentrations and variability overall in all three section types. Levels of tumor necrosis factor alpha (TNF-α) were too low among samples to reliably measure using immunoassay.

Conclusions

Refrigeration of placentae prior to processing does not appear to compromise detection of these cytokines for purposes of large scale studies. These findings provide a framework and preliminary data for the study of inflammatory cytokines within the placenta in large scale and/or resource-limited settings.

Beyond individualism: Is there a place for relational autonomy in clinical practice and research?

The dominant, individualistic understanding of autonomy that features in clinical practice and research is underpinned by the idea that people are, in their ideal form, independent, self-interested and rational gain-maximising decision-makers. In recent decades, this paradigm has been challenged from various disciplinary and intellectual directions. Proponents of ‘relational autonomy’ in particular have argued that people’s identities, needs, interests – and indeed autonomy – are always also shaped by their relations to others. Yet, despite the pronounced and nuanced critique directed at an individualistic understanding of autonomy, this critique has had very little effect on ethical and legal instruments in clinical practice and research so far. In this article, we use four case studies to explore to what extent, if at all, relational autonomy can provide solutions to ethical and practical problems in clinical practice and research. We conclude that certain forms of relational autonomy can have a tangible and positive impact on clinical practice and research. These solutions leave the ultimate decision to the person most affected, but encourage and facilitate the consideration of this person’s care and responsibility for connected others.