Integrative exposomic, transcriptomic, epigenomic analyses of human placental samples links understudied chemicals to preeclampsia

BACKGROUND

Environmental health research has recently undergone a dramatic shift, with ongoing technological advancements allowing for broader coverage of exposure and molecular biology signatures. Approaches to integrate such measures are still needed to increase understanding between systems-level exposure and biology.

OBJECTIVES

We address this gap by evaluating placental tissues to identify novel chemical-biological interactions associated with preeclampsia. This study tests the hypothesis that understudied chemicals are present in the human placenta and associated with preeclampsia-relevant disruptions, including overall case status (preeclamptic vs. normotensive patients) and underlying transcriptomic/epigenomic signatures.

METHODS

A non-targeted analysis based on high-resolution mass spectrometry was used to analyze placental tissues from a cohort of 35 patients with preeclampsia (n = 18) and normotensive (n = 17) pregnancies. Molecular feature data were prioritized for confirmation based on association with preeclampsia case status and confidence of chemical identification. All molecular features were evaluated for relationships to mRNA, microRNA, and CpG methylation (i.e., multi-omic) signature alterations involved in preeclampsia.

RESULTS

A total of 183 molecular features were identified with significantly differentiated abundance in placental extracts of preeclamptic patients; these features clustered into distinct chemical groupings using unsupervised methods. Of these features, 53 were identified (mapping to 40 distinct chemicals) using chemical standards, fragmentation spectra, and chemical metadata. In general, human metabolites had the largest feature intensities and strongest associations with preeclampsia-relevant multi-omic changes. Exogenous drugs were second most abundant and had fewer associations with multi-omic changes. Other exogenous chemicals (non-drugs) were least abundant and had the fewest associations with multi-omic changes.

CONCLUSIONS

These global data trends suggest that human metabolites are heavily intertwined with biological processes involved in preeclampsia etiology, while exogenous chemicals may still impact select transcriptomic/epigenomic processes. This study serves as a demonstration of merging systems exposures with systems biology to better understand chemical-disease relationships.

Predictive modeling of biological responses in the rat liver using in vitro Tox21 bioactivity: Benefits from high-throughput toxicokinetics

Computational methods are needed to more efficiently leverage data from in vitro cell-based models to predict what occurs within whole body systems after chemical insults. This study set out to test the hypothesis that in vitro high-throughput screening (HTS) data can more effectively predict in vivo biological responses when chemical disposition and toxicokinetic (TK) modeling are employed. In vitro HTS data from the Tox21 consortium were analyzed in concert with chemical disposition modeling to derive nominal, aqueous, and intracellular estimates of concentrations eliciting 50% maximal activity. In vivo biological responses were captured using rat liver transcriptomic data from the DrugMatrix and TG-Gates databases and evaluated for pathway enrichment. In vivo dosing data were translated to equivalent body concentrations using HTTK modeling. Random forest models were then trained and tested to predict in vivo pathway-level activity across 221 chemicals using in vitro bioactivity data and physicochemical properties as predictor variables, incorporating methods to address imbalanced training data resulting from high instances of inactivity. Model performance was quantified using the area under the receiver operator characteristic curve (AUC-ROC) and compared across pathways for different combinations of predictor variables. All models that included toxicokinetics were found to outperform those that excluded toxicokinetics. Biological interpretation of the model features revealed that rather than a direct mapping of in vitro assays to in vivo pathways, unexpected combinations of multiple in vitro assays predicted in vivo pathway-level activities. To demonstrate the utility of these findings, the highest-performing model was leveraged to make new predictions of in vivo biological responses across all biological pathways for remaining chemicals tested in Tox21 with adequate data coverage (n = 6617). These results demonstrate that, when chemical disposition and toxicokinetics are carefully considered, in vitro HT screening data can be used to effectively predict in vivo biological responses to chemicals.

Review of the environmental prenatal exposome and its relationship to maternal and fetal health

Environmental chemicals comprise a major portion of the human exposome, with some shown to impact the health of susceptible populations, including pregnant women and developing fetuses. The placenta and cord blood serve as important biological windows into the maternal and fetal environments. In this article we review how environmental chemicals (defined here to include man-made chemicals [e.g., flame retardants, pesticides/herbicides, per- and polyfluoroalkyl substances], toxins, metals, and other xenobiotic compounds) contribute to the prenatal exposome and highlight future directions to advance this research field. Our findings from a survey of recent literature indicate the need to better understand the breadth of environmental chemicals that reach the placenta and cord blood, as well as the linkages between prenatal exposures, mechanisms of toxicity, and subsequent health outcomes. Research efforts tailored towards addressing these needs will provide a more comprehensive understanding of how environmental chemicals impact maternal and fetal health.

Use of Genome Editing Tools in Environmental Health Research

The nature and types of genome editing tools are rapidly expanding and becoming increasingly incorporated into research efforts aimed at understanding human disease. The majority of research involving genome editing has been driven by medical research, with a limited but increasing number of studies currently published in the field of environmental health and toxicology. This review aims to address this research gap by providing a high-level summary of current genome editing techniques and presenting examples of how some of these techniques have been used toxicologically to evaluate environmental exposure-induced disease. Specific strategies surrounding the evaluation of hazardous chemicals, chemical mechanism of action / adverse outcome pathways, and inter-individual response variability are also discussed to aid in the translation of genome editing methods towards toxicological and environmental health research.

Privileged position: preparing nurses to work in the community

Nurses nurse, end of story, but is it? Is nursing any one thing? Nursing is many things and the positions that nurses occupy in any particular setting are multiple. In an educational project aimed at facilitating student learning, I set out to expose the multipositionality of community nursing and to acknowledge that discursive pressures shape and limit practice. A set of resources using story method was produced for use in educational settings. Story method was chosen as an emancipatory vehicle for learning. A worrisome question that arose from reflection on the project was that although the educational aim of the project was emancipatory, did the singularity of the professional voice offered through the stories sabotage that goal?

Contesting competency: cultural safety in advanced nursing practice

A central tenet of the competency approach to nursing education and regulation is that it ensures the safe care of clients and communities with whom nurses work. However, the competency approach is problematic in its conception and application to nursing. Incorporation of this framework into advanced practice requires that its limitations are acknowledged so that current interpretations and applications can be challenged and resisted. Through exploring the concept of cultural competence some of the problems associated with the application of the competency approach to professional nursing practice will be exposed. The issues revealed in this exploration prompt the question whether the competency framework is the best way to ensure competent professional practice.

Clinical, pathologic, and immunologic features of human T-lymphotrophic virus type I-associated infective dermatitis in children

OBJECTIVES

To define the clinical and laboratory features associated with infective dermatitis (ID) and confirm its association with human T-lymphotrophic virus type I (HTLV-I).

DESIGN

A case series of patients with ID were compared with patients with atopic dermatitis (AD), which is an important disease in the differential diagnosis of ID.

SETTING

Patients were recruited from dermatology and pediatric clinics at the University Hospital of the West Indies and the Bustamante Children's Hospital, Kingston, Jamaica.

MAIN OUTCOME MEASURES

Clinical and laboratory features of patients with AD were compared with those of patients with ID.

PATIENTS

Consecutive patients older than 1 1/2 years diagnosed as having ID (n=50) and AD (n=35) were enrolled based on clinical findings.

RESULTS

The mean ages of patients with ID and AD were 6.9 and 7.8 years, respectively. Histologically, both diseases were predominantly chronic dermatitis with propensity for skin colonization with Staphylococcus aureus and beta-hemolytic streptococci; however, the distribution of sites of skin involvement differed. Infection with HTLV-I was the most distinguishing feature among patients with ID, with seropositive results in 100%; only 5 (14%) of the 35 patients with AD had results seropositive for HTLV-I. Infective dermatitis was further characterized by dermatopathic lymphadenitis in 16 (67%) of 24 patients with palpable nodes. Anemia, lymphocytosis, and low albumin and elevated serum globulin levels were more prevalent among patients with ID. Significant elevations of IgA, IgD, and IgG levels were observed among patients with ID compared with those with AD. However, both patients with AD and those with ID had levels of IgD and IgE elevated above the normal range. T-cell subsets among patients with ID revealed T-cell activation with a high percentage of HLA-DR antigen positivity, elevated CD4 (2.4 x 10(9)/L) and CD8 (1.4 x 10(9)/L) cell counts, with an increased CD4/CD8 ratio of 1:73.

CONCLUSION

Infective dermatitis is a distinct clinical entity associated with HTLV-I, which plays a role in the pathogenesis and immune perturbations observed.

Outcomes steering practice: when the ends determine the means

A discussion of outcomes and outcomes measurement will be presented through an examination of achievements of a collaborative project awarded a federal best practice grant in 1995. The project, which established a new service for women of nonEnglish-speaking background, was part of a national venture which sought to benchmark best practice in the primary health care field. The process of benchmarking demanded that the approach to outcomes and outcomes measurement adopted by the project participants be articulated. The approach adopted acknowledges that outcomes are affected by the processes involved in care, which in turn are dependent upon the organisational environment in which care is offered and experienced. Both these contributing factors to outcomes can be hard to measure and, therefore, could be at risk of being omitted from the outcome equation in these economically stringent times. This paper aims to contribute to debate on the topic by recommending an approach to outcomes measurement which is comprehensive, values quality and embraces the short, medium and longer term.

Tropical spastic paraparesis occurring in HTLV-1 associated infective dermatitis. Report of two cases

An association between HTLV-1 infection and infective dermatitis (ID) a relapsing eczematous condition of Jamaican children, was reported in 1990. These patients are at risk of developing other known HTLV-1 related diseases. We have observed the development of HTLV-1 associated myelopathy/tropical spastic paraparesis in two patients, ages 14 and 35 years, who were diagnosed with ID at ages 2 and 10 years, respectively. Infective dermatitis of children serves as an early marker of HTLV-I infection and may predict later development of either the malignant outcome, adult T-cell leukaemia/lymphoma or the neurologic manifestation HAM/TSP among adult carriers of HTLV-1 infection.