The Association of Polymorphisms in Circadian Clock and Lipid Metabolism Genes With 2nd Trimester Lipid Levels and Preterm Birth

Variants in the circadian clock genes PER2 and PER3 associate with familial sleep phase disorders

Delayed sleep phase disorder and advanced sleep phase disorder cause disruption of the circadian clock and present with extreme morning/evening chronotype with unclear role of the genetic etiology, especially for delayed sleep phase disorder. To assess if genotyping can aid in clinical diagnosis, we examined the presence of genetic variants in circadian clock genes previously linked to both sleep disorders in Slovenian patient cohort. Based on Morning-evening questionnaire, we found 15 patients with extreme chronotypes, 13 evening and 2 morning, and 28 controls. Sanger sequencing was used to determine the presence of carefully selected candidate SNPs in regions of the CSNK1D, PER2/3 and CRY1 genes. In a patient with an extreme morning chronotype and a family history of circadian sleep disorder we identified two heterozygous missense variants in PER3 gene, c.1243C>G (NM_001377275.1 (p.Pro415Ala)) and c.1250A>G (NM_001377275.1 (p.His417Arg)). The variants were significantly linked to Advanced sleep phase disorder and were also found in proband's father with extreme morningness. Additionally, a rare SNP was found in PER2 gene in a patient with clinical picture of Delayed sleep phase disorder. The novel variant in PER2 (NM_022817.3):c.1901-218 G>T was found in proband's parent with eveningness, indicating an autosomal dominant inheritance. We identified a family with autosomal dominant inheritance of two PER3 heterozygous variants that can be linked to Advanced sleep phase disorder. We revealed also a rare hereditary form of Delayed sleep phase disorder with a new PER2 variant with autosomal dominant inheritance, shedding the light into the genetic causality.

Circadian characteristics of term and preterm labors

The labor is a physiological event considered to have its own circadian (diurnal) rhythm, but some of the data remain conflicting, especially for preterm births. In this retrospective study, we analyzed the circadian trends of labor onset times in the Slovenian birth cohort from 1990 to 2018 with over 550,000 cases of singleton births. The number of term and preterm labor onsets was calculated for each hour in a day and circadian trends were evaluated for each of the study groups by modeling with a generalized Poisson distribution linked with the cosinor regression model using logarithmic link function. The induced labors were taken as the control group since the timing of labor depends mostly on the working schedule of personnel and not on the intrinsic rhythmic characteristics. For induced labors, the main peak in the number of labor cases was observed in the late morning hours (around 10 AM) for all gestational ages. The prominence of this peak becomes smaller in spontaneous premature labors with gradually disrupting rhythmicity in very preterm and extremely preterm cases. Labors starting with spontaneous contractions peak between 6 and 7 AM and lose the rhythmicity at 35 weeks of gestation while labors starting with a spontaneous rupture of membranes peak at 1 AM and lose the rhythmicity at 31 weeks of gestation, suggesting differences in underlying mechanisms. According to our knowledge, this is the first study that shows differences of circadian trends between different types of spontaneous labors, i.e., labors initiated with contraction and labors initiated with a spontaneous rupture of membranes. Moreover, the obtained results represent evidence of gradual disruption of rhythmicity from mild to extreme prematurity.

Characteristics of insulin resistance in Korean adults from the perspective of circadian and metabolic sensing genes

BACKGROUND

The biological clock allows an organism to anticipate periodic environmental changes and adjust its physiology and behavior accordingly.

OBJECTIVE

This retrospective cross-sectional study examined circadian gene polymorphisms and clinical characteristics associated with insulin resistance (IR).

METHODS

We analyzed data from 1,404 Korean adults aged 30 to 55 with no history of cancer and cardio-cerebrovascular disease. The population was classified according to sex and homeostasis model assessment of insulin resistance (HOMA-IR) values. Demographics, anthropometric and clinical characteristics, and single nucleotide polymorphisms (SNPs) were analyzed with respect to sex, age, and HOMA-IR values. We used association rule mining to identify sets of SNPs from circadian and metabolic sensing genes that may be associated with IR.

RESULTS

Among the subjects, 15.0% of 960 women and 24.3% of 444 men had HOMA-IR values above 2. Most of the parameters differed significantly between men and women, as well as between the groups with high and low insulin sensitivity. Body fat mass of the trunk, which was significantly higher in insulin-resistant groups, had a higher correlation with high sensitivity C-reactive protein and hemoglobin levels in women, and alanine aminotransferase and aspartate aminotransferase levels in men. Homozygous minor allele genotype sets of SNPs rs17031578 and rs228669 in the PER3 gene could be more frequently found among women with HOMA-IR values above 2 (p = .014).

CONCLUSION

Oxidative stress enhanced by adiposity and iron overload, which may also be linked to NRF2 and PER3-related pathways, is related to IR in adulthood. However, due to the small population size in this study, more research is needed.

A Scoping Review of Preterm Birth Risk Factors

Preterm birth is a major cause of neonatal morbidity and mortality, but its etiology and risk factors are poorly understood. We undertook a scoping review to illustrate the breadth of risk factors for preterm birth that have been reported in the literature. We conducted a search in the PubMed database for articles published in the previous 5 years. We determined eligibility for this scoping review by screening titles and abstracts, followed by full-text review. We extracted odds ratios and other measures of association for each identified risk factor in the articles. A total of 2,509 unique articles were identified from the search, of which 314 were eligible for inclusion in our final analyses. We summarized risk factors and their relative impacts in the following categories: Activity, Psychological, Medical History, Toxicology, Genetics, and Vaginal Microbiome. Many risk factors for preterm birth have been reported. It is challenging to synthesize findings given the multitude of isolated risk factors that have been studied, inconsistent definitions of risk factors and outcomes, and use of different covariates in analyses. Novel methods of analyzing large datasets may promote a more comprehensive understanding of the etiology of preterm birth and ability to predict the outcome. KEY POINTS: · Preterm birth is difficult to predict.. · Preterm birth has many diverse risk factors.. · Holistic approaches may yield new insights..

The circadian rhythm: an influential soundtrack in the diabetes story

Type 2 Diabetes Mellitus (T2DM) has been the main category of metabolic diseases in recent years due to changes in lifestyle and environmental conditions such as diet and physical activity. On the other hand, the circadian rhythm is one of the most significant biological pathways in humans and other mammals, which is affected by light, sleep, and human activity. However, this cycle is controlled via complicated cellular pathways with feedback loops. It is widely known that changes in the circadian rhythm can alter some metabolic pathways of body cells and could affect the treatment process, particularly for metabolic diseases like T2DM. The aim of this study is to explore the importance of the circadian rhythm in the occurrence of T2DM via reviewing the metabolic pathways involved, their relationship with the circadian rhythm from two perspectives, lifestyle and molecular pathways, and their effect on T2DM pathophysiology. These impacts have been demonstrated in a variety of studies and led to the development of approaches such as time-restricted feeding, chronotherapy (time-specific therapies), and circadian molecule stabilizers.

Metabolomics insights into the prenatal exposure effects of polybrominated diphenyl ethers on neonatal birth outcomes

BACKGROUND

Effects of polybrominated diphenyl ethers (PBDEs) on neonatal birth outcomes vary across previous studies, and the related mechanism investigation remains poorly understood, especially at the metabolic level.

OBJECTIVES

To evaluate the associations between prenatal PBDEs exposure and neonatal birth outcomes including gestational age, neonatal weight, birth length, head circumference (HC), Apgar score at 1 min (Apgar1) and 5 min, and further reveal the underlying metabolic disorders in a population-based birth cohort study.

METHODS

Gas chromatography-triple quadrupole tandem mass spectrometry (GC-MS/MS) based targeted method and GC-MS based untargeted method were respectively conducted to obtain PBDE levels and metabolic profiles of 200 placental tissue samples from a typical e-waste recycling area (Guiyu) and reference area (Haojiang) in China. Spearman correlation and regression analyses were applied to assess the associations between the placental PBDE levels and birth outcomes. Metabolome-wide association studies and the meet-in-the-middle approach were employed to explore disruptions linking PBDE exposures and the corresponding adverse birth outcomes.

RESULTS

Eight out of 27 PBDE congeners were detected in placenta with more than 50% frequency in at least one district and significantly higher in Guiyu than those in Haojiang. The lower HC and Apgar1 had significant associations with PBDE exposures after adjustment for potential confounders. A total of 66, 16 and 14 metabolites were significantly correlated with PBDE exposures, HC and Apgar1, respectively. 4 and 12 PBDE-related metabolites were significantly associated with the risks of decreasing neonatal HC and Apgar1. The disrupted metabolites were mainly involved in the pentose phosphate pathway, ascorbate metabolism, threonine metabolism, butanoate metabolism, lipid metabolism, and arginine biosynthesis.

CONCLUSIONS

In this birth cohort, higher placental PBDE levels were significantly associated with the lower HC and Apgar1. The associations might be modified by multiple metabolic disturbances through increasing oxidative stress, mediating neurotoxicity, maternal gut microbiota dysbiosis and vasodilatation regulation.

Labour classified by cervical dilatation & fetal membrane rupture demonstrates differential impact on RNA-seq data for human myometrium tissues

High throughput sequencing has previously identified differentially expressed genes (DEGs) and enriched signalling networks in human myometrium for term (≥37 weeks) gestation labour, when defined as a singular state of activity at comparison to the non-labouring state. However, transcriptome changes that occur during transition from early to established labour (defined as ≤3 and >3 cm cervical dilatation, respectively) and potentially altered by fetal membrane rupture (ROM), when adapting from onset to completion of childbirth, remained to be defined. In the present study, we assessed whether differences for these two clinically observable factors of labour are associated with different myometrial transcriptome profiles. Analysis of our tissue (‘bulk’) RNA-seq data (NCBI Gene Expression Omnibus: GSE80172) with classification of labour into four groups, each compared to the same non-labour group, identified more DEGs for early than established labour; ROM was the strongest up-regulator of DEGs. We propose that lower DEGs frequency for early labour and/or ROM negative myometrium was attributed to bulk RNA-seq limitations associated with tissue heterogeneity, as well as the possibility that processes other than gene transcription are of more importance at labour onset. Integrative analysis with future data from additional samples, which have at least equivalent refined clinical classification for labour status, and alternative omics approaches will help to explain what truly contributes to transcriptomic changes that are critical for labour onset. Lastly, we identified five DEGs common to all labour groupings; two of which (AREG and PER3) were validated by qPCR and not differentially expressed in placenta and choriodecidua.

Influence of Dietary Behaviors on Dyslipidemia in Pregnant Women and Its Effects on Physical Development of Fetuses and Infants: A Bidirectional Cohort Study

BACKGROUND

Gestational diabetes can alter the trajectory of fetal development, but there are few studies on the effects of abnormal lipid metabolism on physical development of infants. We aimed to explore the prevalence of maternal dyslipidemia, its influencing factors and effects on the physical development of fetuses and infants, as well as the role of leptin in this process.

METHODS

Questionnaire surveys and main outcome measures were administered among 338 pairs of pregnant women and newborns.

RESULTS

The detection rate of maternal dyslipidemia was 31.5%. The median levels of TG (triglyceride) and TG/HDL (high-density lipoprotein) ratio were higher in large-for-gestational-age (LGA) newborns. Birth weight was positively related to infants' height and weight at six months and one year old (p < 0.05). Leptin was positively related to TG levels of pregnant women and newborns' birth weight (p < 0.05). Logistic regression analysis showed that having greater than or equal to four meals a day (OR = 6.552, 95%CI = 1.014-42.338) and liking to eat lightly flavored food during pregnancy (OR = 1.887, 95%CI = 1.048-3.395) were independent risk factors of maternal dyslipidemia.

CONCLUSIONS

The prevalence of dyslipidemia was relatively high in pregnant women and was affected by dietary behaviors. Abnormal lipid levels during pregnancy could affect weight and length at birth, which might be associated with increasing leptin levels in cord blood, and then the weight of infants would be influenced by birth weight.

Low CLOCK and CRY2 in 2nd trimester human maternal blood and risk of preterm birth: A nested case-control study

Previous studies have observed an association between maternal circadian rhythm disruption and preterm birth (PTB). However, the underlying molecular mechanisms and the potential of circadian clock genes to serve as predictors of PTB remain unexplored. We examined the association of 10 core circadian transcripts in maternal blood with spontaneous PTB (sPTB) vs term births using a nested case-control study design. We used a public gene expression dataset (GSE59491), which was nested within the All Our Babies (AOB) study cohort in Canada. Maternal blood was sampled in trimesters 2-3 from women with sPTB (n = 51) and term births (n = 106), matched for 5 demographic variables. In 2nd trimester maternal blood, only CLOCK and CRY2 transcripts were significantly lower in sPTB vs term (p = 0.02 ~ 0.03, FDR < 0.20). A change of PER3 mRNA from trimesters 2 to 3 was significantly associated with sPTB (decline in sPTB, p = 0.02, FDR < 0.20). When CLOCK and CRY2 were modeled together in 2nd trimester blood, the odds ratio of being in the low level of both circadian gene transcripts was greater in sPTB vs term (OR = 4.86, 95%CI = (1.75,13.51), p < 0.01). Using GSVA and Pearson correlation, we identified 98 common pathways that were negatively or positively correlated with CLOCK and CRY2 expression (all p < 0.05, FDR < 0.10). The top three identified pathways were amyotrophic lateral sclerosis, degradation of extracellular matrix, and inwardly rectifying potassium channels. These three processes have previously been shown to be involved in neuron death, parturition, and uterine excitability during pregnancy, respectively.

hPER3 promotes adipogenesis via hHSP90AA1-mediated inhibition of Notch1 pathway

The period circadian regulator 3 (PER3) has been reported to play a negative role in human immortalized bone marrow-derived Scp-1 cells (iBMSCs) and patient adipose-derived stromal cells (PASCs) or a negative/positive role in mice adipogenesis. However, human PER3 (hPER3) was identified as a positive regulator of human adipose tissue-derived stromal cells (hADSCs) adipogenesis in this study. Silencing or overexpression of hPER3 in hADSCs inhibited and promoted adipogenesis in vitro. In vivo, the overexpression of hPER3 increased high-fat diet-induced inguinal white adipose tissue (iWAT) and epididymal white adipose tissue (eWAT) forms, increasing systemic glucose intolerance and insulin resistance. Molecularly, hPER3 does not interact with hPPARγ, but represses Notch1 signaling pathway to enhance adipogenesis by interacting with hHSP90AA1, which is able to combine with the promoter of hNotch1 and inactivate its expression. Thus, our study revealed hPER3 as a critical positive regulator of hADSCs adipogenesis, which was different from the other types of cells, providing a critical role of it in treating obesity.

Impact of Early Nutrition, Physical Activity and Sleep on the Fetal Programming of Disease in the Pregnancy: A Narrative Review

Early programming is the adaptation process by which nutrition and environmental factors alter development pathways during prenatal growth, inducing changes in postnatal metabolism and diseases. The aim of this narrative review, is evaluating the current knowledge in the scientific literature on the effects of nutrition, environmental factors, physical activity and sleep on development pathways. If in utero adaptations were incorrect, this would cause a mismatch between prenatal programming and adulthood. Adequate caloric intake, protein, mineral, vitamin, and long-chain fatty acids, have been noted for their relevance in the offspring brain functions and behavior. Fetus undernutrition/malnutrition causes a delay in growth and have detrimental effects on the development and subsequent functioning of the organs. Pregnancy is a particularly vulnerable period for the development of food preferences and for modifications in the emotional response. Maternal obesity increases the risk of developing perinatal complications and delivery by cesarean section and has long-term implications in the development of metabolic diseases. Physical exercise during pregnancy contributes to overall improved health post-partum. It is also interesting to highlight the relevance of sleep problems during pregnancy, which influence adequate growth and fetal development. Taking into account these considerations, we conclude that nutrition and metabolic factors during early life play a key role of health promotion and public health nutrition programs worldwide to improve the health of the offspring and the health costs of hospitalization.