Maternal morphine intake during pregnancy and lactation affects the circadian clock of rat pups

Maternal high-fat diet alters the transcriptional rhythm in white adipose tissue of adult offspring

A maternal high-fat diet (HFD) deteriorates the long-term metabolic health of offspring. Circadian rhythms are crucial for regulating metabolism. However, the impact of maternal HFD on the circadian clock in white adipose tissue (WAT) remains unexplored. This study aimed to identify transcriptional rhythmic alterations in inguinal WAT of adult male offspring induced by maternal HFD. To this end, female mice were fed an HFD and their male offspring were raised on a standard chow diet until 16 weeks of age. Transcriptome was performed and the data was analyzed using CircaCompare. The results showed that maternal HFD before and throughout pregnancy significantly altered the circadian rhythm of inguinal WAT while slightly modifying the WAT clock in adult male offspring. Specifically, maternal HFD contributed to gaining rhythmicity of Cry2, resulted in the elevated amplitude of Nr1d2, and led to increased midline estimating statistic of rhythm (MESOR) of Clock and Nr1d2. Furthermore, maternal HFD changed the rhythmic pattern of metabolic genes, such as Pparγ, Hacd2, and Acsl1, which are significantly enriched in metabolic regulation pathways. In conclusion, a maternal HFD before and throughout pregnancy altered the circadian rhythm of inguinal WAT in adult offspring. These alterations may play a significant role in disturbing metabolic homeostasis, potentially leading to metabolic dysfunction in adult male offspring.

Incidence of alternative splicing associated with sex and opioid effects in the axon guidance pathway

The alternative splicing of a gene results in distinct transcript isoforms that can result in proteins that differ in function. Alternative splicing processes are prevalent in the brain, have varying incidence across brain regions, and can present sexual dimorphism. Exposure to opiates and other substances of abuse can also alter the type and incidence of the splicing process and the relative abundance of the isoforms produced. The disruption of alternative splicing patterns associated with sex differences and morphine exposure in the prefrontal cortex of a pig model was studied. The numbers of genes presenting one or more significant (FDR-adjusted p-value < 0.05) alternative splicing events were 933 and 1,368 genes when comparing females relative to males and morphine- relative to saline-treated animals, respectively. The sex-dependent opioid effect was most extreme in the contrast between morphine- versus saline-treated males with 1,934 significantly differentially spliced genes. The most frequent and significant alternative splicing type was skipped exon (∼56 % event), followed by retained intron (∼15 % events). The pathways encompassing a significant number of differentially spliced genes included axon guidance, glutamatergic synapses, circadian rhythm, and lysine degradation. Genes in these pathways included ROBO1, SEMA6C, GRIN3A, GRM2, ARNTL, CLOCK, HYKK, and DOT1L. Transcription factors ETV7 and DMAP1 presented a significant number of differentially spliced target genes. The distribution of the genes presenting differential alternative splicing in the axon guidance and circadian rhythm pathways indicates that this regulatory mechanism impacts hubs and peripheral genes. The identification of sexual dimorphism in the effect of morphine across multiple pathways confirms the necessity to explore the effects of drugs of abuse within sex. Altogether, our findings advance the understanding of the response to factors that can impact the activity of excitatory synapses by modulating transcriptional mechanisms that support the plasticity of the prefrontal cortex.

Impact of Prenatal LPS and Early-life Constant Light Exposure on Circadian Gene Expression Profiles in Various Rat Tissues

Exposure to lipopolysaccharide (LPS) during prenatal development leads to various changes in neurobiological and behavioural patterns. Similarly, continuous exposure to constant light (LL) during the critical developmental period of the circadian system affects gene expression in various tissues in adulthood. Given the reciprocal nature of the interaction between the circadian and the immune systems, our study primarily investigated the individual effects of both interventions and, more importantly, their combined effect. We aimed to explore whether there might be a potential synergistic effect on circadian rhythms and their parameters, focussing on the expression of clock genes, immune-related genes, and specific genes in the hippocampus, pineal gland, spleen and adrenal gland of rats at postnatal day 30. Our results show a significant influence of prenatal LPS and postnatal LL on the expression profiles of all genes assessed. However, the combination of prenatal LPS and postnatal LL only revealed an enhanced negative effect in a minority of the comparisons. In most cases, it appeared to attenuate the changes induced by the individual interventions, restoring the measured parameters to values closer to those of the control group. In particular, genes such as Nr1d1, Aanat and Tph1 showed increased amplitude in the pineal gland and spleen, while the kynurenine enzymes Kynu and KatII developed circadian rhythmicity in the adrenal glands only after the combined interventions. Our data suggest that a mild immunological challenge during prenatal development may play a critical role in triggering an adaptive response of the circadian clock later in life.

Developmental outcomes with perinatal exposure (DOPE) to prescription opioids

Researchers have found considerable evidence in the past 20 years that perinatal opioid exposure leads to an increased risk of developmental disorders in offspring that persist into adulthood. The use of opioids to treat pain concerning pregnancy, delivery, and postpartum complications has been rising. As a result, communities have reported a 300-400 % increase in Neonatal Opioid Withdrawal Syndrome (NOWS). NOWS represents the initial stage of several behavioral, phenotypic, and synaptic deficits. This review article summarizes the Developmental Outcomes of Perinatal Exposure (DOPE) to prescription opioids. Moreover, we also seek to connect these findings to clinical research that describes DOPE at multiple stages of life. Since specific mechanisms that underlie DOPE remain unclear, this article aims to provide a framework for conceptualizing across all ages and highlight the implications they may have for longevity.

Methadone administered to rat dams during pregnancy and lactation affects the circadian rhythms of their pups

The circadian clock is one of the most important homeostatic systems regulating the majority of physiological functions. Its proper development contributes significantly to the maintenance of health in adulthood. Methadone is recommended for the treatment of opioid use disorders during pregnancy, increasing the number of children prenatally exposed to long-acting opioids. Although early-life opioid exposure has been studied for a number of behavioral and physiological changes observed later in life, information on the relationship between the effects of methadone exposure and circadian system development is lacking. Using a rat model, we investigated the effects of prenatal and early postnatal methadone administration on the maturation of the circadian clockwork in the suprachiasmatic nucleus (SCN) and liver, the rhythm of aralkylamine N-acetyltransferase (AA-NAT) activity in the pineal gland, and gene expression in the livers of 20-day-old rats. Our data show that repeated administration of methadone to pregnant and lactating mothers has significant effect on rhythmic gene expression in the SCN and livers and on the rhythm of AA-NAT in the offspring. Similar to previous studies with morphine, the rhythm amplitudes of the clock genes in the SCN and liver were unchanged or enhanced. However, six of seven specific genes in the liver showed significant downregulation of their expression, compared to the controls in at least one experimental group. Importantly, the amplitude of the AA-NAT rhythm was significantly reduced in all methadone-treated groups. As there is a strong correlation with melatonin levels, this result could be of importance for clinical practice.

Efficacy of a Vibrating Crib Mattress to Reduce Pharmacologic Treatment in Opioid-Exposed Newborns: A Randomized Clinical Trial

Importance

Pharmacologic agents are often used to treat newborns with prenatal opioid exposure (POE) despite known adverse effects on neurodevelopment. Alternative nonpharmacological interventions are needed.

Objective

To examine efficacy of a vibrating crib mattress for treating newborns with POE.

Design, Setting, and Participants

In this dual-site randomized clinical trial, 208 term newborns with POE, enrolled from March 9, 2017, to March 10, 2020, were studied at their bedside throughout hospitalization.

Interventions

Half the cohort received treatment as usual (TAU) and half received standard care plus low-level stochastic (random) vibrotactile stimulation (SVS) using a uniquely constructed crib mattress with a 3-hour on-off cycle. Study initiated in the newborn unit where newborns were randomized to TAU or SVS within 48 hours of birth. All infants whose symptoms met clinical criteria for pharmacologic treatment received morphine in the neonatal intensive care unit per standard care.

Main Outcomes and Measures

The a priori primary outcomes analyzed were pharmacotherapy (administration of morphine treatment [AMT], first-line medication at both study sites [number of infants treated], and cumulative morphine dose) and hospital length of stay. Intention-to-treat analysis was conducted.

Results

Analyses were performed on 181 newborns who completed hospitalization at the study sites (mean [SD] gestational age, 39.0 [1.2] weeks; mean [SD] birth weight, 3076 (489) g; 100 [55.2%] were female). Of the 181 analyzed infants, 121 (66.9%) were discharged without medication and 60 (33.1%) were transferred to the NICU for morphine treatment (31 [51.7%] TAU and 29 [48.3%] SVS). Treatment rate was not significantly different in the 2 groups: 35.6% (31 of 87 infants who received TAU) and 30.9% (29 of 94 infants who received SVS) (P = .60). Adjusting for site, sex, birth weight, opioid exposure, and feed type, infant duration on the vibrating mattress in the newborn unit was associated with reduction in AMT (adjusted odds ratio, 0.88 hours per day; 95% CI, 0.81-0.93 hours per day). This translated to a 50% relative reduction in AMT for infants who received SVS on average 6 hours per day. Among 32 infants transferred to the neonatal intensive care unit for morphine treatment who completed treatment within 3 weeks, those assigned to SVS finished treatment nearly twice as fast (hazard ratio, 1.96; 95% CI, 1.01-3.81), resulting in 3.18 fewer treatment days (95% CI, -0.47 to -0.04 days) and receiving a mean 1.76 mg/kg less morphine (95% CI, -3.02 to -0.50 mg/kg) than the TAU cohort. No effects of condition were observed among infants treated for more than 3 weeks (n = 28).

Conclusions and Relevance

The findings of this clinical trial suggest that SVS may serve as a complementary nonpharmacologic intervention for newborns with POE. Reducing pharmacotherapy with SVS has implications for reduced hospitalization stays and costs, and possibly improved infant outcomes given the known adverse effects of morphine on neurodevelopment.

Trial Registration

ClinicalTrials.gov Identifier: NCT02801331.

Circadian rhythms of locomotor activity in rats: Data on the effect of morphine administered from the early stages of embryonic development until weaning

The circadian clock generates behavioural and physiological rhythms to maximize the efficacy of organismal functions. The circadian system with a major circadian pacemaker in the suprachiasmatic nucleus of the hypothalamus develops gradually and its proper function in adulthood depends on an appropriate neurochemical milieu during ontogeny [1]. Locomotor activity is under direct control by the circadian clock, and alterations in its rhythmicity indicate changes of circadian clock function. We evaluated circadian parameters of locomotor rhythms of adult male Wistar rats born to mothers that were exposed to a stable dose of 0.1 mg/ml of morphine in drinking water (36 ml water on average/day/each rat) from embryonic day 10 (E10) until weaning at postnatal day 28 (P28). Increasing the dose of morphine in drinking water was used to evaluate the changes in the rhythmic gene expression in the suprachiasmatic nucleus and in the livers of young rats at P20 [2]. At P90, we started measurement of endogenous rhythmicity for 12 days in constant darkness (DD), then we applied a 15 min light pulse at circadian time 15 (CT15) and followed the animals for the next 15 days in DD. We evaluated the magnitude of light-induced phase shift and compared the circadian parameters of free-running rhythmicity in the intervals before and after the light pulse. All data were also compared between morphine-exposed animals (M group) and controls (C group) that were not exposed to morphine. An unpaired t-test confirmed a significantly longer light-induced phase delay in M group compared with C group, a prolonged circadian period in M group in the interval after the light pulse, and greater amplitude for C group in the first interval, i.e. before the light pulse. No change in total activity counts between groups was confirmed.