Publications by authors named "Larissa Takser"

Background & Aims: Mood disorders and disorders of gut-brain interaction (DGBI) are highly prevalent, commonly comorbid, and lack fully effective therapies. Although selective serotonin reuptake inhibitors (SSRIs) are first-line pharmacological treatments for these disorders, they may impart adverse effects, including anxiety, anhedonia, dysmotility, and, in children exposed in utero, an increased risk of cognitive, mood, and gastrointestinal disorders. SSRIs act systemically to block the serotonin reuptake transporter and enhance serotonergic signaling in the brain, intestinal epithelium, and enteric neurons.

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  • - The study investigates the impact of metal/element exposures on the gut microbiome in children aged 8 to 12, exploring the relationships between 19 different stool metal concentrations and microbiome profiles within a cohort of 116 participants from the GESTE study.
  • - Significant associations were found, such as positive correlations between zinc (Zn) and certain microbiome species, while cadmium (Cd) was linked to declines in specific gut bacteria, indicating that metal exposure could affect the composition of the gut microbiome.
  • - The research also identified 490 functional pathways related to microbiome activities, suggesting that these metal exposures could influence crucial processes like amino acid synthesis and carbohydrate degradation, highlighting the need for further research on their implications
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Background: Dyslipidemias, including familial hypercholesterolemia (FH), are a significant risk factor for cardiovascular diseases. FH is a genetic disorder resulting in elevated levels of low-density lipoprotein cholesterol (LDL-C) and an increased probability of early cardiovascular disorders. Heterozygous familial hypercholesterolemia (HeFH) is the most common form, affecting approximately 1 in 250 individuals worldwide, with a higher prevalence among the French-Canadian population.

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  • * Specific HFRs like brominated diphenyl ethers (PBDEs) were measured in children from eastern Quebec, revealing that indoor environment conditions, such as air purifier usage, affect HFR levels in their bloodstream, with lower brominated compounds linked to better indoor quality.
  • * Seasonal variations were observed, indicating higher levels of certain PBDEs in summer stool samples, while factors such as income and maternal education showed no significant influence on HFR exposure, although emerging compounds correlated with various
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  • A study measured 16 halogenated flame retardants in stool and plasma samples from children aged 8.9-13.8 years in a Canadian cohort, focusing on contaminants and their effects on neurodevelopment.
  • The method used for stool analysis was effective, showing good recovery rates for most compounds, though some specific chemicals exhibited higher variability.
  • The findings revealed significant differences in exposure patterns between stool and blood samples, suggesting that stool could be a valuable addition to blood analysis in future studies of chemical impacts on health, particularly regarding the gut microbiome.
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  • The study investigates children's exposure to various environmental contaminants by analyzing their feces, emphasizing the importance of the gut microbiome in neurodevelopment and its links to health outcomes.
  • Researchers analyzed 73 organic compounds and 22 elements in the feces of children aged 6 and 10 from a middle-class, semi-urban population in Eastern Canada, finding widespread detection of contaminants.
  • Results revealed that caffeine and acetaminophen were notably common, while almost all evaluated elements were found in over 50% of the children, indicating significant exposure levels.
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The apparent increase in the prevalence of the attention deficit hyperactivity disorder (ADHD) diagnosis raises many questions regarding the variability of the subjective diagnostic method. This comprehensive review reports findings in studies assessing white matter (WM) bundles in diffusion MRI and symptom severity in children with ADHD. These studies suggested the involvement of the connections between the frontal, parietal, and basal ganglia regions.

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Pregnant individuals are exposed to acetaminophen and caffeine, but it is unknown how these exposures interact with the developing gut microbiome. We aimed to determine whether acetaminophen and/or caffeine relate to the childhood gut microbiome and whether features of the gut microbiome alter the relationship between acetaminophen/caffeine and neurodevelopment. Forty-nine and 85 participants provided meconium and stool samples at 6-7, respectively, for exposure and microbiome assessment.

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Structural and functional magnetic resonance imaging (MRI) studies have suggested a neuroanatomical basis that may underly attention-deficit-hyperactivity disorder (ADHD), but the anatomical ground truth remains unknown. In addition, the role of the white matter (WM) microstructure related to attention and impulsivity in a general pediatric population is still not well understood. Using a state-of-the-art structural connectivity pipeline based on the Brainnetome atlas extracting WM connections and its subsections, we applied dimensionality reduction techniques to obtain biologically interpretable WM measures.

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Background: The small number of studies examining the association of prenatal acetaminophen with birth outcomes have all relied on maternal self-report. It remains unknown whether prenatal acetaminophen exposure measured in a biological specimen is associated with birth outcomes.

Objectives: To investigate the association of acetaminophen measured in meconium with birthweight, gestational age, preterm birth, size for gestational age, gestational diabetes, preeclampsia, and high blood pressure.

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Background: The gut microbiome is important in modulating health in childhood. Metal exposures affect multiple health outcomes, but their ability to modify bacterial communities in children is poorly understood.

Objectives: We assessed the associations of childhood and perinatal blood metal levels with childhood gut microbiome diversity, structure, species, gene family-inferred species, and potential pathway alterations.

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Background: Prenatal exposure to persistent organic pollutants (POPs), widespread in North America, is associated with increased Attention Deficit/Hyperactivity Disorder (ADHD) symptoms and may be a modifiable risk for ADHD phenotypes. However, the effects of moderate exposure to POPs on task-based inhibitory control performance, related brain function, and ADHD-related symptoms remain unknown, limiting our ability to develop interventions targeting the neural impact of common levels of exposure.

Objectives: The goal of this study was to examine the association between prenatal POP exposure and inhibitory control performance, neural correlates of inhibitory control and ADHD-related symptoms.

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  • * Reports on a pilot study measuring maternal levels of various persistent organic pollutants (POPs) and their impact on lipid metabolism in children aged 6-7.
  • * Finds that in utero exposure to specific PBDEs and PCBs is linked to lower levels of triglycerides and other lipids in children, hinting at a potential risk for fatty liver disease (NAFLD).
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Unlabelled: Previous studies suggest a negative association between prenatal polybrominated diphenyl ethers (PBDEs) exposure and child cognitive and psychomotor development. However, the timing of the relationship between PBDE exposure and neurodevelopment is still unclear. We examined the association between PBDE concentration at two different prenatal times (early and late pregnancy) and cognitive function in children 6-8 years of age.

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  • The halogenated flame retardants (HFRs) market has shifted from the heavy use of polybrominated diphenyl ether (PBDE) to newer mixtures like Firemaster 550 and Firemaster 680, which include non-PBDE compounds.
  • This review examines the advancements from 2010-2020 in methods for analyzing HFRs in human samples, including blood, milk, and hair, using gas chromatography and mass spectrometry techniques.
  • Despite new HFRs being detected in human specimens, PBDEs and Dechlorane Plus remain the predominant flame retardants, with higher levels found in people working near industrial areas.
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In previous studies, the total content of urinary phthalate metabolites was commonly used to evaluate human exposure to phthalates. However, phthalate metabolites are mainly present in urine in two forms, conjugated and free. These metabolite forms in urine are more relevant to the biotransformation pathways of the phthalates in humans.

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Importance: Despite evidence of an association between prenatal acetaminophen exposure and attention-deficit/hyperactivity disorder (ADHD) in offspring, the drug is not contraindicated during pregnancy, possibly because prior studies have relied on maternal self-report, failed to quantify acetaminophen dose, and lacked mechanistic insight.

Objective: To examine the association between prenatal acetaminophen exposure measured in meconium (hereinafter referred to as meconium acetaminophen) and ADHD in children aged 6 to 7 years, along with the potential for mediation by functional brain connectivity.

Design, Setting, And Participants: This prospective birth cohort study from the Centre Hospitalier Université de Sherbrooke in Sherbrooke, Québec, Canada, included 394 eligible children, of whom 345 had meconium samples collected at delivery and information on ADHD diagnosis.

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Background: Parabens, which are used as a preservative in foods and personal care products, are detected in nearly 100% of human urine samples. Exposure to parabens is associated with DNA damage, male infertility, and endocrine disruption in adults, but the effects of prenatal exposure are unclear. In part, this is due to inadequate assessment of exposure in maternal urine, which may only reflect maternal rather than fetal exposure.

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Background: The overwhelming number of potentially toxic chemicals in consumer products and in our daily environment makes it unrealistic to carry out in-depth analyses of each product with the objective of banning and eliminating toxic chemicals from our environment.

Objectives: To present the challenges that environmental toxicology and epidemiology are currently facing in the context of ubiquitous chemical pollution.

Discussion: We propose a realistic and pragmatic approach to this Herculean problem.

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Three hexachloronorbornene-based flame retardants and five polybrominated diphenyl ethers (PBDEs) were measured in 414 human plasma samples, (169 from children, 167 from mothers, and 78 from fathers), collected from 200 families between 2014 and 2016. The median concentration of ∑PBDEs (sum of BDE-47, -99, -100, -153 and -183) was 13.2 ng/g lipid for child, 9.

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Context: Underlying mechanisms leading to gestational diabetes mellitus (GDM) are still under investigation, and it is unclear whether the placenta plays a role in triggering glucose intolerance or if its functions are modified in response to the hyperglycemia. Circulating miRNAs are involved in placental development and function and are encapsulated in extracellular vesicles (EVs).

Objective: To compare differential expression of miRNAs in circulating EVs in pregnancies complicated by GDM vs controls.

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Background: The gut microbiome is influenced by early-life exposures, but-despite potentially enormous implications for child health-is understudied in environmental epidemiology. This pilot study is one of the first to explore exposures and long-term gut microbiome profiles. We examined the association between exposure to polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) during pregnancy and the mid-childhood gut microbiome.

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Evaluating in utero exposure to inorganic and multiclass organic contaminants is critical to better evaluate potential harmful effects on prenatal and postnatal development. The analysis of meconium, the first bowel discharge of the newborn, has been proposed as a non-invasive way to assess cumulative prenatal exposure. The aim of this study was to implement an analytical method for quantifying 72 targeted organic compounds, including pesticides, pharmaceutical compounds and daily life xenobiotics, in meconium in addition to selected elements (17 elements).

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Acetaminophen is the only over-the-counter pain reliever that is not contraindicated during pregnancy, but recent studies have questioned whether acetaminophen is safe for the fetus, particularly the developing brain. This prospective birth cohort study probed the previously observed association between in utero exposure to acetaminophen and neurodevelopment by using concentrations of acetaminophen measured in meconium, which more objectively captures exposure of the fetus than maternal report. Exposure, measured by liquid chromatography coupled with tandem mass spectrometry, was categorized into nondetection, low detection, and high detection levels.

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Background: Folates in their role as key one carbon donors, are essential for two major pathways: the synthesis of DNA and RNA precursors and DNA methylation. A growing body of evidence from epidemiological studies indicates a possible association between nutritional and functional deficiency in folates and Autism Spectrum Disorders (ASD). However, there are no available behavioral animal studies on periconceptional one‑carbon donor deficiency during gestation and the autistic phenotype.

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