White Matter Injury and Structural Anomalies in Infants with Prenatal Opioid Exposure

Methadone directly impairs central nervous system cells in vitro

Methadone is a synthetic long-acting opioid that is increasingly used in the replacement therapy of opioid-addicted patients, including pregnant women. However, methadone therapy in this population poses challenges, as it induces cognitive and behavioral impairments in infants exposed to this opioid during prenatal development. In animal models, prenatal methadone exposure results in detrimental consequences to the central nervous system, such as: (i) increased neuronal apoptosis; (ii) disruption of oligodendrocyte maturation and increased apoptosis and (iii) increased microglia and astrocyte activation. However, it remains unclear whether these deleterious effects result from a direct effect of methadone on brain cells. Therefore, our goal was to uncover the impact of methadone on single brain cell types in vitro. Primary cultures of rat neurons, oligodendrocytes, microglia, and astrocytes were treated for three days with 10 µM methadone to emulate a chronic administration. Apoptotic neurons were identified by cleaved caspase-3 detection, and synaptic density was assessed by the juxtaposition of presynaptic and postsynaptic markers. Apoptosis of oligodendrocyte precursors was determined by cleaved caspase-3 detection. Oligodendrocyte myelination was assessed by immunofluorescence, while microglia and astrocyte proinflammatory activation were assessed by both immunofluorescence and RT-qPCR. Methadone treatment increased neuronal apoptosis and reduced synaptic density. Furthermore, it led to increased oligodendrocyte apoptosis and a reduction in the myelinating capacity of these cells, and promoted the proinflammatory activation of microglia and astrocytes. We showed that methadone, the most widely used drug in opioid replacement therapy for pregnant women with opioid addiction, directly impairs brain cells in vitro, highlighting the need for developing alternative therapies to address opioid addiction in this population.

Sex differences in neonatal outcomes following prenatal opioid exposure

The impact of the opioid epidemic on pregnant people and children is a growing public health crisis. Understanding how opioids affect the developing brain during pregnancy and postnatally remains a critical area of investigation. Biological sex plays a crucial role in all physiologic processes, with the potential for a significant impact on neonatal outcomes, including those infants with opioid exposure. Here, we aim to explore current literature on the effect of sex on neonatal outcomes following prenatal opioid exposure. Sex differences in adults with opioid use disorder have been well studied, including increased mortality among males and higher rates of psychiatric comorbidities and likelihood of relapse in females. However, such differences are not yet well understood in neonates. Emerging clinical data suggest sex-specific effects in infants with prenatal opioid exposure on the expression of genes related to feeding regulation and reward signaling pathways. Increased susceptibility to white matter injury has also been noted in female infants following prenatal opioid exposure. Understanding the impact of sex as a biological variable on neonatal outcomes following prenatal opioid exposure is paramount to improving the health and well-being of infants, children, and adults impacted by the opioid epidemic.

A Prospective Multi-Institutional Study Comparing the Brain Development in the Third Trimester between Opioid-Exposed and Nonexposed Fetuses Using Advanced Fetal MR Imaging Techniques

BACKGROUND AND PURPOSE

While the adverse neurodevelopmental effects of prenatal opioid exposure on infants and children in the United States are well described, the underlying causative mechanisms have yet to be fully understood. This study aims to compare quantitative volumetric and surface-based features of the fetal brain between opioid-exposed fetuses and unexposed controls by using advanced MR imaging processing techniques.

MATERIALS AND METHODS

This is a multi-institutional IRB-approved study in which pregnant women with and without opioid use during the current pregnancy were prospectively recruited to undergo fetal MR imaging. A total of 14 opioid-exposed (31.4 ± 2.3 weeks of gestation) and 15 unexposed (31.4 ± 2.4 weeks) fetuses were included. Whole brain volume, cortical plate volume, surface area, sulcal depth, mean curvature, and gyrification index were computed as quantitative features by using our fetal brain MR imaging processing pipeline.

RESULTS

After correcting for gestational age, fetal sex, maternal education, polysubstance use, high blood pressure, and MR imaging acquisition site, all of the global morphologic features were significantly lower in the opioid-exposed fetuses compared with the unexposed fetuses, including brain volume, cortical volume, cortical surface area, sulcal depth, cortical mean curvature, and gyrification index. In regional analysis, the opioid-exposed fetuses showed significantly decreased surface area and sulcal depth in the bilateral Sylvian fissures, central sulci, parieto-occipital fissures, temporal cortices, and frontal cortices.

CONCLUSIONS

In this small cohort, prenatal opioid exposure was associated with altered fetal brain development in the third trimester. This adds to the growing body of literature demonstrating that prenatal opioid exposure affects the developing brain.

DTI of Opioid-Exposed Fetuses Using ComBat Harmonization: A Bi-Institutional Study

BACKGROUND AND PURPOSE

The underlying mechanisms leading to altered cognitive, behavioral, and vision outcomes in children with prenatal opioid exposure are yet to be fully understood. Some studies suggest WM alterations in infants and children with prenatal opioid exposure; however, the time course of WM changes is unknown. We aimed to evaluate differences in diffusion tensor imaging MRI parameters in the brain between opioid exposed fetuses and normal controls.

MATERIALS AND METHODS

This is a pilot, prospective cohort study in which subjects in the third trimester of pregnancy underwent fetal DTI of the brain with 20 noncolinear diffusion directions and a b-value of 500 s/mm2 at 2.5-mm isotropic resolution.

RESULTS

The study included a total of 26 fetuses, 11 opioid-exposed (mean gestational age, 32.61 [SD, 2.35] weeks) and 15 unexposed controls (mean gestational age, 31.77 [SD, 1.68] weeks). After we adjusted for gestational age, fractional anisotropy values were significantly higher in opioid-exposed fetuses relative to controls in 8 WM tracts: the bilateral lemniscus (left: P = .017; right: P = .020), middle cerebellar peduncle (P = .027), left inferior cerebellar peduncle (P = .026), right sagittal stratum (P = .040), right fornix stria terminalis (P = .022), right inferior fronto-occipital fasciculus (P = .011), and the right uncinate fasciculus (P = .033). Significant alteration was also identified in other DTI indices involving a series of brain regions.

CONCLUSIONS

Our data demonstrate initial evidence of cerebral WM microstructural differences between opioid-exposed fetuses and unexposed controls. Further studies in larger patient populations will be needed to fully understand these findings.

A review of the genomics of neonatal abstinence syndrome

Neonatal abstinence syndrome (NAS) is a constellation of signs of withdrawal occurring after birth following in utero exposure to licit or illicit opioids. Despite significant research and public health efforts, NAS remains challenging to diagnose, predict, and manage due to highly variable expression. Biomarker discovery in the field of NAS is crucial for stratifying risk, allocating resources, monitoring longitudinal outcomes, and identifying novel therapeutics. There is considerable interest in identifying important genetic and epigenetic markers of NAS severity and outcome that can guide medical decision making, research efforts, and public policy. A number of recent studies have suggested that genetic and epigenetic changes are associated with NAS severity, including evidence of neurodevelopmental instability. This review will provide an overview of the role of genetics and epigenetics in short and longer-term NAS outcomes. We will also describe novel research efforts using polygenic risk scores for NAS risk stratification and salivary gene expression to understand neurobehavioral modulation. Finally, emerging research focused on neuroinflammation from prenatal opioid exposure may elucidate novel mechanisms that could lead to development of future novel therapeutics.

In utero methadone exposure permanently alters anatomical and functional connectivity: A preclinical evaluation

The opioid epidemic is an ongoing public health crisis, and children born following prenatal opioid exposure (POE) have increased risk of long-term cognitive and behavioral sequelae. Clinical studies have identified reduced gray matter volume and abnormal white matter microstructure in children with POE but impacts on whole-brain functional brain connectivity (FC) have not been reported. To define effects of POE on whole brain FC and white matter injury in adult animals, we performed quantitative whole-brain structural and functional MRI. We used an established rat model of POE in which we have previously reported impaired executive function in adult rats analogous to persistent neurocognitive symptoms described in humans with POE. Pregnant Sprague-Dawley rat dams received continuous methadone (12 mg/kg/day) vs. saline infusion for 28 days via osmotic mini-pumps, exposing rats to pre- and postnatal opioid until weaning. At young adult age (P60), POE and saline exposed offspring underwent in vivo MRI included diffusion tensor imaging and functional MRI (fMRI). Results indicate that fractional anisotropy (FA) was decreased in adult animals with POE [n = 11] compared to animals that received saline [n = 9] in major white matter tracts, including the corpus callosum (p < 0.001) and external capsule (p < 0.01). This change in FA was concomitant with reduced axial diffusivity in the external capsule (p < 0.01) and increased radial diffusivity in the corpus callosum (p < 0.01). fMRI analyses reveal brainwide FC was diffusely lower in POE (p < 10^-6; 10% of variance explained by group). Decreased connectivity in cortical-cortical and cortico-basal ganglia circuitry was particularly prominent with large effect sizes (Glass's Δ > 1). Taken together, these data confirm POE reduces brainwide functional connectivity as well as microstructural integrity of major white matter tracts. Altered neural circuitry, dysregulated network refinement, and diffuse network dysfunction have been implicated in executive function deficits that are common in children with POE. FC may serve as a translatable biomarker in children with POE.

Alterations of brain microstructures in a mouse model of prenatal opioid exposure detected by diffusion MRI

Growing opioid use among pregnant women is fueling a crisis of infants born with prenatal opioid exposure. A large body of research has been devoted to studying the management of opioid withdrawal during the neonatal period in these infants, but less substantive work has explored the long-term impact of prenatal opioid exposure on neurodevelopment. Using a translationally relevant mouse model of prenatal methadone exposure (PME), the aim of the study is to investigate the cerebral microstructural differences between the mice with PME and prenatal saline exposure (PSE). The brains of eight-week-old male offspring with either PME (n = 15) or PSE (n = 15) were imaged using high resolution in-vivo diffusion magnetic resonance imaging on a 9.4 Tesla small animal scanner. Brain microstructure was characterized using diffusion tensor imaging (DTI) and Bingham neurite orientation dispersion and density imaging (Bingham-NODDI). Voxel-based analysis (VBA) was performed using the calculated microstructural parametric maps. The VBA showed significant (p < 0.05) bilateral alterations in fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), radial diffusivity (RD), orientation dispersion index (ODI) and dispersion anisotropy index (DAI) across several cortical and subcortical regions, compared to PSE. Particularly, in PME offspring, FA, MD and AD were significantly higher in the hippocampus, dorsal amygdala, thalamus, septal nuclei, dorsal striatum and nucleus accumbens. These DTI-based results suggest widespread bilateral microstructural alterations across cortical and subcortical regions in PME offspring. Consistent with the observations in DTI, Bingham-NODDI derived ODI exhibited significant reduction in PME offspring within the hippocampus, dorsal striatum and cortex. NODDI-based results further suggest reduction in dendritic arborization in PME offspring across multiple cortical and subcortical regions. To our best knowledge, this is the first study of prenatal opioid exposure to examine microstructural organization in vivo. Our findings demonstrate perturbed microstructural complexity in cortical and subcortical regions persisting into early adulthood which could interfere with critical neurodevelopmental processes in individuals with prenatal opioid exposure.

Outcomes of Babies with Opioid Exposure (OBOE): protocol of a prospective longitudinal cohort study

BACKGROUND

While the health, social, and economic impacts of opioid addiction on adults and their communities are well known, the impact of maternal opioid use on the fetus exposed in utero is less well understood.

METHODS

This paper presents the protocol of the ACT NOW Outcomes of Babies with Opioid Exposure (OBOE) Study, a multi-site prospective longitudinal cohort study of infants with antenatal opioid exposure and unexposed controls. Study objectives are to determine the impact of antenatal opioid exposure on brain development and neurodevelopmental outcomes over the first 2 years of life and explore whether family, home, and community factors modify developmental trajectories during this critical time period.

RESULTS

Primary outcomes related to brain development include cortical volumes, deep cerebral gray matter volumes, resting-state functional connectivity measures, and structural connectivity measures using diffusion tensor imaging. Primary neurodevelopmental outcomes include visual abnormalities, cognitive, language, and motor skills measured using the Bayley Scales of Infant Development and social-emotional and behavioral problems and competence measured by the Brief Infant-Toddler Social and Emotional Assessment.

CONCLUSIONS

The OBOE study has been designed to overcome challenges of previous studies and will help further understanding of the effects of antenatal opioid exposure on early infant development.

IMPACT

This study will integrate MRI findings and comprehensive neurodevelopmental assessments to provide early insights into the functional topography of the brain in this high-risk population and assess MRI as a potential biomarker. Rather than conducting neuroimaging at a single time point, the study will include serial MRI assessments from birth to 2 years, allowing for the examination of trajectories throughout this period of rapid brain development. While previous studies often have had limited information on exposures, this study will use umbilical cord assays to accurately measure amounts of opioids and other substances from 20 weeks of gestation to birth.

Cerebral perfusion and neurological examination characterise neonatal opioid withdrawal syndrome: a prospective cohort study

OBJECTIVE

To test the hypothesis that cerebral blood flow (CBF) assessed with arterial spin labelling (ASL) MRI is increased and standardised neurological examination is altered in infants with neonatal opioid withdrawal syndrome (NOWS) compared with those without.

DESIGN

Prospective cohort study.

SETTING

Level IV neonatal intensive care unit and outpatient primary care centre.

PARTICIPANTS

Infants with NOWS receiving pharmacological treatment and unexposed controls matched for gestational age at birth and post-menstrual age at MRI.

MAIN OUTCOMES

CBF assessed by ASL on non-sedated 3-Tesla MRI and standardised Hammersmith Neonatal Neurological Examination (HNNE) within 14 days of birth.

RESULTS

Thirty infants with NOWS and 31 control infants were enrolled and included in the final analysis. Global CBF across the brain was higher in the NOWS group compared with controls (14.2 mL/100 g/min±5.5 vs 10.7 mL/100 g/min±4.3, mean±SD, Cohen's d=0.72). HNNE total optimality score was lower in the NOWS group compared with controls (25.9±3.6 vs 28.4±2.4, mean±SD, Cohen's d=0.81). A penalised logistic regression model including both CBF and HNNE items discriminated best between the two groups.

CONCLUSIONS

Increased cerebral perfusion and neurological examination abnormalities characterise infants with NOWS compared with those without intrauterine drug exposure and suggest prenatal substance exposure affects fetal brain development. Identifying neurological and neuroimaging characteristics of infants with NOWS can contribute to understanding mechanisms underlying later outcomes and to designing potential new treatments.

Distinct Synaptic Vesicle Proteomic Signatures Associated with Pre- and Post-Natal Oxycodone-Exposure

The current opioid crisis, which has ravaged all segments of society, continues to pose a rising public health concern. Importantly, dependency on prescription opioids such as oxycodone (oxy) during and after pregnancy can significantly impact the overall brain development of the exposed offspring, especially at the synapse. A significant knowledge gap that remains is identifying distinct synaptic signatures associated with these exposed offspring. Accordingly, the overall goal of this current study was to identify distinct synaptic vesicle (SV) proteins as signatures for offspring exposed to oxy in utero (IUO) and postnatally (PNO). Using a preclinical animal model that imitates oxycodone exposure in utero (IUO) and postnatally (PNO), we used a quantitative mass spectrometry-based proteomics platform to examine changes in the synaptic vesicle proteome on post-natal day 14 (P14) IUO and PNO offspring. We identified MEGF8, associated with carpenter syndrome, to be downregulated in the IUO offspring while LAMTOR4, associated with the regulator complex involved in lysosomal signaling and trafficking, was found to be upregulated in the PNO groups, respectively. Their respective differential expression was further validated by Western blot. In summary, our current study shows exposure to oxy in utero and postnatally can impact the SV proteome in the exposed offspring and the identification of these distinct SV signatures could further pave the way to further elucidate their downstream mechanisms including developing them as potential therapeutic targets.

Thalamocortical functional connectivity in infants with prenatal opioid exposure correlates with severity of neonatal opioid withdrawal syndrome

PURPOSE

Prenatal opioid exposure (POE) is a growing public health concern due to its associated adverse outcomes including neonatal opioid withdrawal syndrome (NOWS). The aim of this study was to assess alterations in thalamic functional connectivity in neonates with POE using resting-state functional magnetic resonance imaging (rs-fMRI) and identify whether these altered connectivity measures were associated with NOWS severity.

METHODS

In this prospective, IRB-approved study, we performed rs-fMRI in 19 infants with POE and 20 healthy control infants without POE. Following standard pre-processing, we performed seed-based functional connectivity analysis with the right and left thalamus as the regions of interest. We performed post hoc analysis in the prenatal opioid exposure group to identify associations of altered thalamocortical connectivity with severity of NOWS. P value of < .05 was considered statistically significant.

RESULTS

There were several regions of significantly altered thalamic to cortical functional connectivity in infants with POE compared to the healthy infants. Distinct regions of thalamocortical functional connectivity correlated with maximum modified Finnegan score. Association between thalamocortical connectivity and severity of NOWS was nominally modified by maternal psychological conditions and polysubstance use.

CONCLUSION

Our findings reveal prenatal opioid exposure-related alterations in thalamic functional connectivity in the infant brain that are correlated with severity of NOWS. Future studies may benefit from evaluation of thalamocortical resting state functional connectivity in infants with POE to help  stratify risk of long term neurodevelopmental outcomes.

Pilot study of fetal brain development and morphometry in prenatal opioid exposure and smoking on fetal MRI

PURPOSE

The purpose of this study was to assess for any differences in brain maturation, structure and morphometry in fetuses exposed to opioids in utero, compared to non-opioid exposed fetuses on fetal MRI.

METHODS

We performed a prospective study in pregnant women using opioids and healthy pregnant women without prenatal opioid use. We evaluated brain maturation, structure, and morphometry on second or third trimester fetal MRI and assessed group differences.

RESULTS

28 pregnant women were enrolled, 12 with opioid exposure (average gestational age 33.67, range 28-39 w), 9 of whom also smoked, and 16 without opioid exposure (average gestational age 32.53, range 27-38 w). There was a significant difference in the anteroposterior diameter of the fetal cerebellar vermis in the opioid exposed fetuses compared to non-opioid exposed fetuses (p = 0.004). There were no significant differences in brain biparietal diameter, fronto-occipital diameter, transverse cerebellar diameter and anteroposterior dimension of the pons in opioid exposed fetuses compared to non-opioid exposed fetuses. There were no abnormalities in brain maturation and no major brain structural abnormalities in the opioid exposed fetuses.

CONCLUSION

Smaller fetal anteroposterior cerebellar vermian dimension was associated with in utero opioid exposure. There were no abnormalities in brain maturation or major structural abnormalities in fetuses exposed to opioids.

The immediate and long-term effects of prenatal opioid exposure

The opioid epidemic has adversely affected neonates and children, yet the mechanisms by which it impacts this population are not well understood. Not only does prenatal opioid exposure result in short-term consequences shortly after birth, it also creates long-term sequelae that may predispose these children to physical, emotional, psychiatric, cognitive, and socioeconomic problems in the future. This article provides a scoping overview of the long-term effects of antenatal opioid exposure on neonates and children as well as quality improvement and research efforts to understand and mitigate this major public health concern.

Global Brain Functional Network Connectivity in Infants With Prenatal Opioid Exposure

BACKGROUND

Infants with prenatal opioid and substance exposure are at higher risk of poor neurobehavioral outcomes in later childhood. Early brain imaging in infancy has the potential to identify early brain developmental alterations that may help predict behavioral outcomes in these children. In this study, using resting-state functional MRI in early infancy, we aim to identify differences in global brain network connectivity in infants with prenatal opioid and substance exposure compared to healthy control infants.

METHODS AND MATERIALS

In this prospective study, we recruited 23 infants with prenatal opioid exposure and 29 healthy opioid naïve infants. All subjects underwent brain resting-state functional MRI before 3 months postmenstrual age. Covariate Assisted Principal (CAP) regression was performed to identify brain networks within which functional connectivity was associated with opioid exposure after adjusting for sex and gestational age. Associations of these significant networks with maternal comorbidities were also evaluated. Additionally, graph network metrics were assessed in these CAP networks.

RESULTS

There were four CAP network components that were significantly different between the opioid exposed and healthy control infants. Two of these four networks were associated with maternal psychological factors. Intra-network graph metrics, namely average flow coefficient, clustering coefficient and transitivity were also significantly different in opioid exposed infants compared to healthy controls.

CONCLUSION

Prenatal opioid exposure is associated with alterations in global brain functional networks compared to non-opioid exposed infants, with intra-network alterations in graph network modeling. These network alterations were also associated with maternal comorbidity, especially mental health. Large-scale longitudinal studies can help in understanding the clinical implications of these early brain functional network alterations in infants with prenatal opioid exposure.

Co-occurrence of preconception maternal childhood adversity and opioid use during pregnancy: Implications for offspring brain development

Understanding of the effects of in utero opioid exposure on neurodevelopment is a priority given the recent dramatic increase in opioid use among pregnant individuals. However, opioid abuse does not occur in isolation-pregnant individuals abusing opioids often have a significant history of adverse experiences in childhood, among other co-occurring factors. Understanding the specific pathways in which these frequently co-occurring factors may interact and cumulatively influence offspring brain development in utero represents a priority for future research in this area. We highlight maternal history of childhood adversity (CA) as one such co-occurring factor that is more prevalent among individuals using opioids during pregnancy and which is increasingly shown to affect offspring neurodevelopment through mechanisms beginning in utero. Despite the high incidence of CA history in pregnant individuals using opioids, we understand very little about the effects of comorbid prenatal opioid exposure and maternal CA history on fetal brain development. Here, we first provide an overview of current knowledge regarding effects of opioid exposure and maternal CA on offspring neurodevelopment that may occur during gestation. We then outline potential mechanistic pathways through which these factors might have interactive and cumulative influences on offspring neurodevelopment as a foundation for future research in this area.

Improving translational relevance: The need for combined exposure models for studying prenatal adversity

Prenatal environmental adversity is a risk factor for neurodevelopmental disorders (NDDs), with the neuroimmune environment proposed to play a role in this risk. Adverse maternal exposures are associated with cognitive consequences in the offspring that are characteristics of NDDs and simultaneous neuroimmune changes that may underlie NDD risk. In both animal models and human studies the association between prenatal environmental exposure and NDD risk has been shown to be complex. Maternal overnutrition/obesity and opioid use are two different examples of complex exposure epidemics, each with their own unique comorbidities. This review will examine maternal obesity and maternal opioid use separately, illustrating the pervasive comorbidities with each exposure to argue a need for animal models of compound prenatal exposures. Many of these comorbidities can impact neuroimmune function, warranting systematic investigation of combined exposures to begin to understand this complexity. While traditional approaches in animal models have focused on modeling a single prenatal exposure or second exposure later in life, a translational approach would begin to incorporate the most prevalent co-occurring prenatal exposures. Long term follow-up in humans is extremely challenging, so animal models can provide timely insight into neurodevelopmental consequences of complex prenatal exposures. Animal models that represent this translational context of comorbid exposures behind maternal obesity or comorbid exposures behind maternal opioid use may reveal potential synergistic neuroimmune interactions that contribute to cognitive consequences and NDD risk. Finally, translational co-exposure models can identify concerning exposure combinations to guide treatment in complex cases, and identify high risk children starting in the prenatal period where early interventions improve prognosis.

Endogenous and exogenous opioid effects on oligodendrocyte biology and developmental brain myelination

The elevated presence of opioid receptors and their ligands throughout the developing brain points to the existence of maturational functions of the endogenous opioid system that still remain poorly understood. The alarmingly increasing rates of opioid use and abuse underscore the urgent need for clear identification of those functions and the cellular bases and molecular mechanisms underlying their physiological roles under normal and pathological conditions. This review is focused on current knowledge on the direct and indirect regulatory roles that opioids may have on oligodendrocyte development and their generation of myelin, a complex insulating membrane that not only facilitates rapid impulse conduction but also participates in mechanisms of brain plasticity and adaptation. Information is examined in relation to the importance of endogenous opioid function, as well as direct and indirect effects of opioid analogues, which like methadone and buprenorphine are used in medication-assisted therapies for opioid addiction during pregnancy and pharmacotherapy in neonatal abstinence syndrome. Potential opioid effects are also discussed regarding late myelination of the brain prefrontal cortex in adolescents and young adults. Such knowledge is fundamental for the design of safer pharmacological interventions for opioid abuse, minimizing deleterious effects in the developing nervous system.

A Holistic Systems Approach to Characterize the Impact of Pre- and Post-natal Oxycodone Exposure on Neurodevelopment and Behavior

Background: Increased risk of oxycodone (oxy) dependency during pregnancy has been associated with altered behaviors and cognitive deficits in exposed offspring. However, a significant knowledge gap remains regarding the effect of in utero and postnatal exposure on neurodevelopment and subsequent behavioral outcomes. Methods: Using a preclinical rodent model that mimics oxy exposure in utero (IUO) and postnatally (PNO), we employed an integrative holistic systems biology approach encompassing proton magnetic resonance spectroscopy (1H-MRS), electrophysiology, RNA-sequencing, and Von Frey pain testing to elucidate molecular and behavioral changes in the exposed offspring during early neurodevelopment as well as adulthood. Results: 1H-MRS studies revealed significant changes in key brain metabolites in the exposed offspring that were corroborated with changes in synaptic currents. Transcriptomic analysis employing RNA-sequencing identified alterations in the expression of pivotal genes associated with synaptic transmission, neurodevelopment, mood disorders, and addiction in the treatment groups. Furthermore, Von Frey analysis revealed lower pain thresholds in both exposed groups. Conclusions: Given the increased use of opiates, understanding the persistent developmental effects of these drugs on children will delineate potential risks associated with opiate use beyond the direct effects in pregnant women.

Use of Phenobarbital to Treat Neonatal Abstinence Syndrome From Exposure to Single vs. Multiple Substances

Drug use in pregnancy is a major public health issue. Intrauterine exposure to opioids alone or in addition to other substances may lead to neonatal abstinence syndrome (NAS). Little consensus exists on optimal therapy, especially for those exposed to multiple drugs. We aim to determine whether the use of opioids alone vs. in combination with phenobarbital will affect short-term neonatal outcomes. This retrospective review of infants admitted to the neonatal intensive care unit (NICU) included newborns ≥35 weeks of gestation exposed to opioids, or multiple substances including opioids, in utero. Treatment with opioids alone, and addition of phenobarbital as initial therapy vs. rescue, was evaluated. Out of 182 newborns, 54 (30%) were exposed to methadone alone vs. 128 (70%) to multiple drugs. Length of stay (LOS) in the hospital was not significantly affected (p = 0.684) by single vs. multiple drug exposure in utero. Treatment of NAS with opioid alone resulted in significantly shorter LOS (27 days), as compared to those treated with opioid and phenobarbital (45 days, p < 0.001). LOS was further prolonged in those treated with phenobarbital as a "rescue" medication in addition to an opioid (49 days, p < 0.0001). There was a significant increase in LOS and duration of opioid treatment for all infants treated with phenobarbital, both in those exposed to opioids alone, and to multiple substances in utero.

Neuroimaging in infants with prenatal opioid exposure: Current evidence, recent developments and targets for future research

Prenatal opioid exposure (POE) has shown to be a risk factor for adverse long-term cognitive and behavioral outcomes in offspring. However, the neural mechanisms of these outcomes remain poorly understood. While preclinical and human studies suggest that these outcomes may be due to opioid-mediated changes in the fetal and early postnatal brain, other maternal, social, and environmental factors are also shown to play a role. Recent neuroimaging studies reveal brain alterations in children with POE. Early neuroimaging and novel methodology could provide an in vivo mechanistic understanding of opioid mediated alterations in developing brain. However, this is an area of ongoing research. In this review we explore recent imaging developments in POE, with emphasis on the neonatal and infant brain, and highlight some of the challenges of imaging the developing brain in this population. We also highlight evidence from animal models and imaging in older children and youth to understand areas where future research may be targeted in infants with POE.