Prenatal cannabinoid exposure and altered neurotransmission

Prenatal Cannabis Use and Maternal Pregnancy Outcomes

Importance

Many studies have evaluated whether in utero cannabis exposure is associated with fetal and neonatal outcomes, yet little is known about whether prenatal cannabis use is associated with maternal health outcomes during pregnancy.

Objective

To evaluate whether prenatal cannabis use is associated with maternal health outcomes during pregnancy.

Design, Setting, and Participants

This population-based retrospective cohort study included pregnancies in Northern California from January 2011 to December 2019 that lasted 20 weeks or longer and were screened for prenatal cannabis use.

Exposures

Prenatal cannabis use was defined as any self-reported use during early pregnancy or a positive toxicology test result based on universal screening at entrance to prenatal care (approximately 8-10 weeks' gestation). Self-reported frequency of use (daily, weekly, monthly or less, never, unknown), use defined only by self-report, and use defined only by toxicology test results were examined.

Main Outcomes and Measures

Electronic health record data were used to define the following outcomes: gestational hypertension, preeclampsia, eclampsia, gestational diabetes, gestational weight gain greater and less than guidelines, placenta previa, placental abruption, placenta accreta, and severe maternal morbidity. Adjusted risk ratios (aRRs) were calculated using a modified Poisson regression.

Results

The sample (n = 316 722 pregnancies; 250 221 unique individuals) included 84 039 (26.5%) Asian/Pacific Islander, 20 053 (6.3%) Black, 83 145 (26.3%) Hispanic, and 118 333 (37.4%) White individuals; the mean (SD) age was 30.6 (5.4) years. Overall, 20 053 (6.3%) screened positive for prenatal cannabis use; 2.9% were positive by self-report, 5.3% by toxicology testing, and 1.8% by both. The frequency of cannabis use was 1930 (0.6%) daily, 2345 (0.7%) weekly, 4892 (1.5%) monthly or less, and 10 886 (3.4%) unknown. Prenatal cannabis use was associated with greater risk of gestational hypertension (aRR, 1.17; 95% CI, 1.13-1.21), preeclampsia (aRR, 1.08; 95% CI, 1.01-1.15), weight gain less than (aRR, 1.05; 95% CI, 1.01-1.08) and greater than (aRR, 1.09; 95% CI, 1.08-1.10) guidelines, and placental abruption (aRR, 1.19; 95% CI, 1.05-1.36). The pattern of results was similar when defining prenatal cannabis use only by self-report or only by toxicology testing, and associations between the frequency of prenatal cannabis use and outcomes varied with outcome.

Conclusions and Relevance

The results of this cohort study suggest that prenatal cannabis use was associated with several adverse maternal health outcomes during pregnancy. Continued research is needed to understand whether characteristics of prenatal cannabis use (eg, dose, mode, and timing) moderate these associations.

Prenatal MAM exposure raises kynurenic acid levels in the prefrontal cortex of adult rats

BACKGROUND

Elevated brain levels of kynurenic acid (KYNA), a metabolite in the kynurenine pathway, are associated with cognitive dysfunctions, which are nowadays often considered as fundamental characteristics of several psychopathologies; however, the role of KYNA in mental illnesses, such as schizophrenia, is not fully elucidated. This study aimed to assess KYNA levels in the prefrontal cortex (PFC) of rats prenatally treated with methylazoxymethanol (MAM) acetate, i.e., a well-validated neurodevelopmental animal model of schizophrenia. The effects of an early pharmacological modulation of the endogenous cannabinoid system were also evaluated.

METHODS

Pregnant Sprague-Dawley rats were treated with MAM (22 mg/kg, ip) or its vehicle at gestational day 17. Male offspring were treated with the cannabinoid CB1 receptor antagonist/inverse agonist AM251 (0.5 mg/kg/day, ip) or with the typical antipsychotic haloperidol (0.6 mg/kg/day, ip) from postnatal day (PND) 19 to PND39. The locomotor activity and cognitive performance were assessed in the novel object recognition test and the open field test in adulthood. KYNA levels in the PFC of prenatally MAM-treated rats were also assessed.

RESULTS

A significant cognitive impairment was observed in prenatally MAM-treated rats (p < 0.01), which was associated with enhanced PFC KYNA levels (p < 0.05). The peripubertal AM251, but not haloperidol, treatment ameliorated the cognitive deficit (p < 0.05), by normalizing the PFC KYNA content in MAM rats.

CONCLUSIONS

The present findings suggest that the cognitive deficit observed in MAM rats may be related to enhanced PFC KYNA levels which could be, in turn, mediated by the activation of cannabinoid CB1 receptor. These results further support the modulation of brain KYNA levels as a potential therapeutic strategy to ameliorate the cognitive dysfunctions in schizophrenia.

Prenatal Cannabinoid Exposure Elicits Memory Deficits Associated with Reduced PSA-NCAM Expression, Altered Glutamatergic Signaling, and Adaptations in Hippocampal Synaptic Plasticity

Cannabis is now one of the most commonly used illicit substances among pregnant women. This is particularly concerning since developmental exposure to cannabinoids can elicit enduring neurofunctional and cognitive alterations. This study investigates the mechanisms of learning and memory deficits resulting from prenatal cannabinoid exposure (PCE) in adolescent offspring. The synthetic cannabinoid agonist WIN55,212-2 was administered to pregnant rats, and a series of behavioral, electrophysiological, and immunochemical studies were performed to identify potential mechanisms of memory deficits in the adolescent offspring. Hippocampal-dependent memory deficits in adolescent PCE animals were associated with decreased long-term potentiation (LTP) and enhanced long-term depression (LTD) at hippocampal Schaffer collateral-CA1 synapses, as well as an imbalance between GluN2A- and GluN2B-mediated signaling. Moreover, PCE reduced gene and protein expression of neural cell adhesion molecule (NCAM) and polysialylated-NCAM (PSA-NCAM), which are critical for GluN2A and GluN2B signaling balance. Administration of exogenous PSA abrogated the LTP deficits observed in PCE animals, suggesting PSA mediated alterations in GluN2A- and GluN2B- signaling pathways may be responsible for the impaired hippocampal synaptic plasticity resulting from PCE. These findings enhance our current understanding of how PCE affects memory and how this process can be manipulated for future therapeutic purposes.

Cannabis during pregnancy: A way to transfer an impairment to later life

Epidemiological studies examining the influence of cannabis across the lifespan show that exposure to cannabis during gestation or during the perinatal period is associated with later-life mental health issues that manifest during childhood, adolescence, and adulthood. The risk of later-life negative outcomes following early exposure is particularly high in persons who have specific genetic variants, implying that cannabis usage interacts with genetics to heighten mental health risks. Prenatal and perinatal exposure to psychoactive components has been shown in animal research to be associated with long-term effects on neural systems relevant to psychiatric and substance use disorders. The long-term molecular, epigenetic, electrophysiological, and behavioral consequences of prenatal and perinatal exposure to cannabis are discussed in this article. Animal and human studies, as well as in vivo neuroimaging methods, are used to provide insights into the changes induced in the brain by cannabis. Here, based on the literature from both animal models and humans, it can be concluded that prenatal cannabis exposure alters the developmental route of several neuronal regions with correlated functional consequences evidenced as changes in social behavior and executive functions throughout life.

Prenatal alcohol and tetrahydrocannabinol exposure: Effects on spatial and working memory

Introduction

Alcohol and cannabis are widely used recreational drugs that can negatively impact fetal development, leading to cognitive impairments. However, these drugs may be used simultaneously and the effects of combined exposure during the prenatal period are not well understood. Thus, this study used an animal model to investigate the effects of prenatal exposure to ethanol (EtOH), Δ-9-tetrahydrocannabinol (THC), or the combination on spatial and working memory.

Methods

Pregnant Sprague-Dawley rats were exposed to vaporized ethanol (EtOH; 68 ml/h), THC (100 mg/ml), the combination, or vehicle control during gestational days 5-20. Adolescent male and female offspring were evaluated using the Morris water maze task to assess spatial and working memory.

Results

Prenatal THC exposure impaired spatial learning and memory in female offspring, whereas prenatal EtOH exposure impaired working memory. The combination of THC and EtOH did not exacerbate the effects of either EtOH or THC, although subjects exposed to the combination were less thigmotaxic, which might represent an increase in risk-taking behavior.

Discussion

Our results highlight the differential effects of prenatal exposure to THC and EtOH on cognitive and emotional development, with substance- and sex-specific patterns. These findings highlight the potential harm of THC and EtOH on fetal development and support public health policies aimed at reducing cannabis and alcohol use during pregnancy.

Impact of Prenatal Cannabis Use Disorder on Perinatal Outcomes

OBJECTIVES

With legislative changes to cannabis legalization and increasing prevalence of use, cannabis is the most commonly used federally illicit drug in pregnancy. Our study aims to assess the perinatal outcomes associated with prenatal cannabis use disorder.

METHODS

We conducted a retrospective cohort study using California linked hospital discharge-vital statistics data and included singleton, nonanomalous births occurring between 23 and 42 weeks of gestational age. χ 2 Test and multivariable logistic regression were used for statistical analyses.

RESULTS

A total of 2,380,446 patients were included, and 9144 (0.38%) were identified as using cannabis during pregnancy. There was a significantly increased risk for adverse birthing person outcomes, including gestational hypertension (adjusted odds ratio [AOR], 1.19; 95% confidence interval [CI], 1.06-1.34; P = 0.004), preeclampsia (AOR, 1.16; 95% CI, 1.0-1.28; P = 0.006), preterm delivery (AOR, 1.45; 95% CI, 1.35-1.55; P < 0.001), and severe maternal morbidity (AOR, 1.22; 95% CI, 1.02-1.47; P = 0.033). Prenatal cannabis use disorder was also associated with an increased risk of neonatal outcomes including respiratory distress syndrome (AOR, 1.16; 95% CI, 1.07-1.27; P < 0.001), small for gestational age (AOR, 1.47; 95% CI, 1.38-1.56; P < 0.001), neonatal intensive care unit admission (AOR, 1.24; 95% CI, 1.16-1.33; P < 0.001), and infant death (AOR, 1.86; 95% CI, 1.44-2.41; P < 0.001). There was no statistically significant difference in stillbirth (AOR, 0.96; 95% CI, 0.69-1.34; P = 0.80) and hypoglycemia (AOR, 1.22; 95% CI, 1.00-1.49; P = 0.045).

CONCLUSIONS

Our study suggests that prenatal cannabis use disorder is associated with increased maternal and neonatal morbidity and mortality. As cannabis use disorder in pregnancy is becoming more prevalent, our findings can help guide preconception and prenatal counseling.

Emerging Roles of Endocannabinoids as Key Lipid Mediators for a Successful Pregnancy

In recent years, Cannabis use/misuse for treating pregnancy-related symptoms and other chronic conditions has increased among pregnant women, favored by decriminalization and/or legalization of its recreational uses in addition to its easy accessibility. However, there is evidence that prenatal Cannabis exposure might have adverse consequences on pregnancy progression and a deleterious impact on proper neurodevelopmental trajectories in the offspring. Maternal Cannabis use could interfere with the complex and finely controlled role performed by the endocannabinoid system in reproductive physiology, impairing multiple gestational processes from blastocyst implantation to parturition, with long-lasting intergenerational effects. In this review, we discuss current clinical and preclinical evidence regarding the role of endocannabinoids in development, function, and immunity of the maternal–fetal interface, focusing on the impact of Cannabis constituents on each of these gestational processes. We also discuss the intrinsic limitations of the available studies and the future perspectives in this challenging research field.

Alcohol & cannabinoid co-use: Implications for impaired fetal brain development following gestational exposure

Alcohol and marijuana are two of the most consumed psychoactive substances by pregnant people, and independently, both substances have been associated with lifelong impacts on fetal neurodevelopment. Importantly, individuals of child-bearing age are increasingly engaging in simultaneous alcohol and cannabinoid (SAC) use, which amplifies each drug's pharmacodynamic effects and increases craving for both substances. However, to date, investigations of prenatal polysubstance use are notably limited in both human and non-human populations. In this review paper, we will address what is currently known about combined exposure to these substances, both directly and prenatally, and identify shared prenatal targets from single-exposure paradigms that may highlight susceptible neurobiological mechanisms for future investigation and therapeutic intervention. Finally, we conclude this manuscript by discussing factors that we feel are essential in the consideration and experimental design of future preclinical SAC studies.

Neuroimaging revealed long-lasting glucose metabolism changes to morphine withdrawal in rats pretreated with the cannabinoid agonist CP-55,940 during periadolescence

This study evaluates the long-term effects of a six and 14-week morphine withdrawal in rats pretreated with a cannabinoid agonist (CP-55,940, CP) during periadolescence. Wistar rats (33 males; 32 females) were treated with CP or its vehicle (VH) from postnatal day (PND) 28-38. At PND100, rats performed morphine self-administration (MSA, 15d/12 h/session). Eight groups were defined according to pretreatment (CP), treatment (morphine), and sex. Three [¹⁸F]FDG-PET brain images were acquired: after MSA, and after six and 14 weeks of withdrawal. PET data were analyzed with SPM12. Endocannabinoid (EC) markers were evaluated in frozen brain tissue at endpoint. Females showed a higher mean number of self-injections than males. A main Sex effect on global brain metabolism was found. FDG uptake in males was discrete, whereas females showed greater brain metabolism changes mainly in areas of the limbic system after morphine treatment. Moreover, the morphine-induced metabolic pattern in females was exacerbated when CP was previously present. In addition, the CP-Saline male group showed reduced CB1R, MAGL expression, and NAPE/FAAH ratio compared to the control group, and morphine was able to reverse CB1R and MAGL expression almost to control levels. In conclusion, females showed greater and longer-lasting metabolic changes after morphine withdrawal than males, indicating a higher vulnerability and a different sensitivity to morphine in subjects pre-exposed to CP. In contrast, males primarily showed changes in EC markers. Together, our results suggest that CP pre-exposure contributes to the modulation of brain metabolism and EC systems in a sex-dependent manner.

Prenatal cannabis exposure predicts attention problems, without changes on fMRI in adolescents

OBJECTIVES

We hypothesized that prenatal cannabis exposure (PCE) would be associated with increased attention problems and altered neurocognition in young adolescents.

METHODS

Data were obtained from the Adolescent Brain Cognitive Development (ABCD study®), a cohort of approximately 12,000 children. Presence or absence of PCE after knowledge of pregnancy was measured by caregiver report. All participants with PCE (N = 224) were included and compared to two control groups; those matched on tobacco and alcohol exposure and those without prenatal tobacco or alcohol exposures. Outcomes were measured with the ABCD baseline assessment when participants were 9-10 years old and included attention, internalizing, externalizing and total problems scales on the Child Behavior Checklist (CBCL). Teacher reports were used when available. Mixed effects modeling assessed the association between PCE and outcomes controlling for parental psychopathology, prematurity and socioeconomic status. For participants with available data, patterns of brain activity during three fMRI tasks (the Stop Signal Task measuring response inhibition, the Monetary Incentive Delay (MID) task measuring reward processing and the EN-Back task measuring working memory) were analyzed using Permutation Analyses of the Linear Model.

RESULTS

Compared to both control groups, participants with PCE had significantly higher attention problems, externalizing, and total problem scores. PCE did not impact cognitive performance or patterns of brain activation during fMRI tasks.

CONCLUSIONS

There are long-term associations between PCE and early adolescent attention and behavioral problems. These are not reflected in cognitive performance or task fMRI measures, a finding that is consistent with reports that fewer than half of children with ADHD have any specific cognitive deficit (Nigg et al., 2005; Willcutt et al., 2005). The young age of the sample may also relate to this finding and future investigation of neurodevelopmental trajectories of youth with PCE is warranted.

Use of Marijuana: Effect on Brain Health: A Scientific Statement From the American Heart Association

Marijuana is perceived as a harmless drug, and its recreational use has gained popularity among young individuals. The concentration of active ingredients in recreational formulations has gradually increased over time, and high-potency illicit cannabinomimetics have become available. Thus, the consumption of cannabis in the general population is rising. Data from preclinical models demonstrate that cannabinoid receptors are expressed in high density in areas involved in cognition and behavior, particularly during periods of active neurodevelopment and maturation. In addition, growing evidence highlights the role of endogenous cannabinoid pathways in the regulation of neurotransmitter release, synaptic plasticity, and neurodevelopment. In animal models, exogenous cannabinoids disrupt these important processes and lead to cognitive and behavioral abnormalities. These data correlate with the higher risk of cognitive impairment reported in some observational studies done in humans. It is unclear whether the effect of cannabis on cognition reverts after abstinence. However, this evidence, along with the increased risk of stroke reported in marijuana users, raises concerns about its potential long-term effects on cognitive function. This scientific statement reviews the safety of cannabis use from the perspective of brain health, describes mechanistically how cannabis may cause cognitive dysfunction, and advocates for a more informed health care worker and consumer about the potential for cannabis to adversely affect the brain.

Effects of prenatal synthetic cannabinoid exposure on the cerebellum of adolescent rat offspring

Cannabis is the most commonly used illicit drug worldwide. Recently, cannabis use among young pregnant women has greatly increased. However, prenatal cannabinoid exposure leads to long-lasting cognitive, motor, and behavioral deficits in the offspring and alterations in neural circuitry through various mechanisms. Although these effects have been studied in the hippocampus, the effects of prenatal cannabinoid exposure on the cerebellum are not well elucidated. The cerebellum plays an important role in balance and motor control, as well as cognitive functions such as attention, language, and procedural memories. The aim of this study was to investigate the effects of prenatal cannabinoid exposure on the cerebellum of adolescent offspring. Pregnant rats were treated with synthetic cannabinoid agonist WIN55,212-2, and the offspring were evaluated for various cerebellar markers of oxidative stress, mitochondrial function, and apoptosis. Additionally, signaling proteins associated with glutamate dependent synaptic plasticity were examined. Administration of WIN55,212-2 during pregnancy altered markers of oxidative stress by significantly reducing oxidative stress and nitrite content. Mitochondrial Complex I and Complex IV activities were also enhanced following prenatal cannabinoid exposure. With regard to apoptosis, pP38 levels were significantly increased, and proapoptotic factor caspase-3 activity, pERK, and pJNK levels were significantly decreased. CB1R and GluA1 levels remained unchanged; however, GluN2A was significantly reduced. There was a significant decrease in MAO activity although tyrosine hydroxylase activity was unaltered. Our study indicates that the effects of prenatal cannabinoid exposure on the cerebellum are unique compared to other brain regions by enhancing mitochondrial function and promoting neuronal survival. Further studies are required to evaluate the mechanisms by which prenatal cannabinoid exposure alters cerebellar processes and the impact of these alterations on behavior.