Shift work as an oxidative stressor

Mechanisms of oxidative stress in interstitial cystitis/bladder pain syndrome

Interstitial cystitis/bladder pain syndrome (IC/BPS) is characterized by bladder and/or pelvic pain, increased urinary urgency and frequency and nocturia. The pathophysiology of IC/BPS is poorly understood, and theories include chronic inflammation, autoimmune dysregulation, bacterial cystitis, urothelial dysfunction, deficiency of the glycosaminoglycan (GAG) barrier and urine cytotoxicity. Multiple treatment options exist, including behavioural interventions, oral medications, intravesical instillations and procedures such as hydrodistension; however, many clinical trials fail, and patients experience an unsatisfactory treatment response, likely owing to IC/BPS phenotype heterogeneity and the use of non-targeted interventions. Oxidative stress is implicated in the pathogenesis of IC/BPS as reactive oxygen species impair bladder function via their involvement in multiple molecular mechanisms. Kinase signalling pathways, nociceptive receptors, mast-cell activation, urothelial dysregulation and circadian rhythm disturbance have all been linked to reactive oxygen species and IC/BPS. However, further research is necessary to fully uncover the role of oxidative stress in the pathways driving IC/BPS pathogenesis. The development of new models in which these pathways can be manipulated will aid this research and enable further investigation of promising therapeutic targets.

Nonalcoholic Fatty Liver Disease in Shift Workers and Its Effect on Peripheral Nerve Conduction: A Cross-Sectional Study

Introduction Nonalcoholic fatty liver disease (NAFLD) presents as a multisystem disorder, heightening the risk of developing type 2 diabetes mellitus (T2DM) and cardiovascular diseases (CVDs). Occupation emerges as a significant factor influencing the occurrence of NAFLD. Research indicates that individuals engaged in shift work face an elevated risk of NAFLD, alongside obesity and T2DM, attributed to disruptions in their circadian rhythm, which precipitate hepatic steatosis and inflammation. Remarkably, peripheral neuropathy has been observed in conjunction with advanced liver disorders and NAFLD in the general population. However, the correlation between NAFLD and peripheral neuropathy remains unestablished in shift workers. Objective To identify NAFLD in seemingly healthy rotating shift workers and assess any potential impact of NAFLD on nerve function in this demographic. Methods This cross-sectional study involved 73 apparently healthy nonalcoholic security guards (aged 35 to 60 years) working in rotating shifts. The study included a comprehensive assessment, beginning with a medical history, an evaluation of physical activity, and anthropometric measurements. Confirmation of NAFLD was achieved through abdominal ultrasonography (USG), followed by the analysis of biochemical parameters. Motor and sensory nerve conduction studies (NCS) were conducted on participants with normal vitamin B12 levels using the Aleron electromyograph (EMG) machine (Recorders and Medicare Systems Private Ltd, Budanpur, India). The evaluation encompassed the Median and Common Peroneal motor nerves, as well as Median and Sural sensory nerves. Recorded parameters for motor nerves included distal motor latency (DML), compound muscle action potential (CMAP) amplitude, conduction velocity (CV), and F-wave minimum latency (F-wave), while sensory nerve parameters comprised sensory onset latency (SOL), sensory nerve action potential (SNAP) amplitude, and CV. Results Among 73 healthy security guards working in rotating shifts, 76.1% were diagnosed with NAFLD through abdominal ultrasound. Following participant withdrawals and exclusions due to vitamin B12 deficiency, a comparison of NCS parameters between NAFLD (n=24) and Non-NAFLD (n=12) groups revealed no significant disparities in motor or sensory parameters, except for a slightly diminished CMAP amplitude in the peroneal nerve of NAFLD subjects (8.21±2.83mV vs ±10.22±2.30 mV, p< 0.040). However, these differences fell within normal ranges, indicating no notable impact on peripheral nerve conduction in the presence of NAFLD. Conclusion The results indicate a high prevalence of NAFLD among individuals working rotating shifts. Moreover, the investigation suggests that despite the presence of NAFLD, there is no discernible influence on motor and sensory peripheral nerve conduction, particularly in common peroneal, median, and sural nerves.

Chrono-modulated effects of external stressors on oxidative stress and damage in humans: A scoping review on night shift work

BACKGROUND

Oxidative stress and tissue damage (OSD) play a pivotal role as an early-stage process in chronic disease pathogenesis. However, there has been little research to better understand the temporal (χρόνος[chronos]) dimensions of OSD process associated with environmental (non-genetic, including behaviors/lifestyle) and/or occupational stressors, like night shift work. OSD processes have recently attracted attention in relation to time-resolved external stressor trajectories in personalized medicine (prevention) initiatives, as they seem to interact with circadian clock systems towards the improved delineation of the early stages of (chronic) disease process.

OBJECTIVES

This work critically reviewed human studies targeting the temporal dynamics of OSD and circadian clock system's activity in response to environmental/occupational stressors; the case of night shift work was examined.

METHODS

Being a key stressor influencing OSD processes and circadian rhythm, night shift work was evaluated as part of a scoping review of research in OSD, including inflammatory and metabolic processes to determine the extent of OSD research undertaken in human populations, methodologies, tools and biomarkers used and the extent that the temporal dimensions of exposure and biological effect(s) were accounted for. Online databases were searched for papers published from 2000 onwards, resulting in the selection of 53 original publications.

RESULTS AND DISCUSSION

The majority of studies (n = 41) took place in occupational settings, while the rest were conducted in the general population or patient groups. Most occupational studies targeted outcomes of oxidative stress/damage (n = 19), followed by the combination of OSD with inflammatory response (n = 10), and studies focused on metabolic outcomes (n = 12). Only a minor fraction of the studies measured biomarkers related to circadian rhythm, such as, melatonin, its metabolite, or cortisol. Night shift work was associated with select biomarkers of OSD and inflammation, albeit with mixed results. Although much progress in delineating the biological mechanisms of OSD process has been made, an equally thorough investigation on the temporal trajectory of OSD processes as triggered by environmental/occupational stressors in human studies has yet to fully evolve.

CircadiOmics: circadian omic web portal

Circadian rhythms are a foundational aspect of biology. These rhythms are found at the molecular level in every cell of every living organism and they play a fundamental role in homeostasis and a variety of physiological processes. As a result, biomedical research of circadian rhythms continues to expand at a rapid pace. To support this research, CircadiOmics (http://circadiomics.igb.uci.edu/) is the largest annotated repository and analytic web server for high-throughput omic (e.g. transcriptomic, metabolomic, proteomic) circadian time series experimental data. CircadiOmics contains over 290 experiments and over 100 million individual measurements, across >20 unique tissues/organs, and 11 different species. Users are able to visualize and mine these datasets by deriving and comparing periodicity statistics for oscillating molecular species including: period, amplitude, phase, P-value and q-value. These statistics are obtained from BIO_CYCLE and JTK_CYCLE and are intuitively aggregated and displayed for comparison. CircadiOmics is the most up-to-date and cutting-edge web portal for searching and analyzing circadian omic data and is used by researchers around the world.

Sleep Loss Causes Dysfunction in Murine Extraorbital Lacrimal Glands

Purpose

Sleep loss markedly affects the structure and function of the lacrimal gland and may cause ocular surface disease as a common public health problem. This study aims to investigate the circadian disturbance caused by sleep loss leading to dysfunction of extraorbital lacrimal glands (ELGs).

Methods

A mouse sleep deprivation (SD) model for sleep loss studies was built in C57BL/6J male mice. After four weeks, the ELGs were collected at three-hour intervals during a 24-hour period. The Jonckheere-Terpstra-Kendall algorithm was used to determine the composition, phase, and rhythmicity of transcriptomic profiles in ELGs. Furthermore, we compared the non-sleep-deprived and SD-treated mouse ELG (i) reactive oxygen species (ROS) by fluorescein staining, (ii) DNA damage by immunostaining for γ-H2Ax, and (iii) circadian migration of immune cells by immunostaining for CD4, CD8, γδ-TCR, CD64, and CX3CR1. Finally, we also evaluated (i) the locomotor activity and core body temperature rhythm of mice and (ii) the mass, cell size, and tear secretion of the ELGs.

Results

SD dramatically altered the composition and phase-associated functional enrichment of the circadian transcriptome, immune cell trafficking, metabolism, cell differentiation, and neural secretory activities of mouse ELGs. Additionally, SD caused the ROS accumulation and consequent DNA damage in the ELGs, and the ELG dysfunction caused by SD was irreversible.

Conclusions

SD damages the structure, function, and diurnal oscillations of ELGs. These results highlight comprehensive characterization of insufficient sleep–affected ELG circadian transcriptome that may provide a new therapeutic approach to counteract the effects of SD on ELG function.

Sleep Deprivation, Immune Suppression and SARS-CoV-2 Infection

Sleep health and its adaptation to individual and environmental factors are crucial to promote physical and mental well-being across animal species. In recent years, increasing evidence has been reported regarding the relationship between sleep and the immune system and how sleep disturbances may perturb the delicate balance with severe repercussions on health outcomes. For instance, experimental sleep deprivation studies in vivo have reported several major detrimental effects on immune health, including induced failure of host defense in rats and increased risk for metabolic syndrome (MetS) and immune suppression in humans. In addition, two novel risk factors for dysregulated metabolic physiology have recently been identified: sleep disruption and circadian misalignment. In light of these recent findings about the interplay between sleep and the immune system, in this review, we focus on the relationship between sleep deprivation and immunity against viruses, with a special interest in SARS-CoV-2 infection.

Bioinformatics and Systems Biology of Circadian Rhythms: BIO_CYCLE and CircadiOmics

Circadian rhythms are fundamental to biology and medicine and today these can be studied at the molecular level in high-throughput fashion using various omic technologies. We briefly present two resources for the study of circadian omic (e.g. transcriptomic, metabolomic, proteomic) time series. First, BIO_CYCLE is a deep-learning-based program and web server that can analyze omic time series and statistically assess their periodic nature and, when periodic, accurately infer the corresponding period, amplitude, and phase. Second, CircadiOmics is the larges annotated repository of circadian omic time series, containing over 260 experiments and 90 million individual measurements, across multiple organs and tissues, and across 9 different species. In combination, these tools enable powerful bioinformatics and systems biology analyses. The are currently being deployed in a host of different projects where they are enabling significant discoveries: both tools are publicly available over the web at: http://circadiomics.ics.uci.edu/ .

Rotating night shift work, sleep duration and elevated gamma-glutamyl transpeptidase among steelworkers: cross-sectional analyses from a Chinese occupational cohort

OBJECTIVES

This study aimed to evaluate the separate and combined effects of rotating night shift work and lifestyle factors with elevated gamma-glutamyl transpeptidase (GGT) among steelworkers.

DESIGN, SETTING AND PARTICIPANTS

This cross-sectional study used the baseline information from a Chinese occupational cohort. The in-service workers of the production department of Tangsteel Company who participated in the occupational health examination in Tangshan from February to June 2017 were selected as the research objects.

MAIN OUTCOME MEASURES

The separate and combined effects of rotating night shift work and lifestyle factors with elevated GGT among steelworkers.

RESULTS

The information of 7031 subjects from the production department of Tangsteel Company was analysed. Results showed that the current shift workers and the workers with the duration of night shifts>19 years, the cumulative number of night shifts>1774 nights, the average frequency of night shifts≤7 nights/month and the average frequency of night shifts>7 nights/month had elevated odds of elevated GGT, compared with those who never worked night shifts, and ORs, (95% CIs) were 1.39, (1.10 to 1.75), 1.46, (1.15 to 1.86), 1.46, (1.15 to 1.85), 1.34, (1.04 to 1.73) and 1.37, (1.09 to 1.74) after adjustment for potential confounders. The independent effect of shorter sleep duration (<7 hours/day) on elevated GGT was not statistically significant. Among workers who had shorter sleep duration, the association between rotating night shift work and elevated GGT was statistically significant, but no associations were found among workers with the sleep duration of ≥7 hours/day. In addition, other lifestyle factors affected the association between rotating night shift work and elevated GGT.

CONCLUSIONS

Rotating night shift work is associated with elevated GGT among steelworkers. In particular, the effect of rotating night shift work on elevated GGT was affected by sleep duration and other lifestyle factors.

Influences of Occupational Burnout and Personality on Lipid Peroxidation Among Nurses in Shahroud City, Iran

Considering the relationship between occupational burnout and oxidative stress, identifying the factors that affect occupational burnout, such as recognizing individual characteristics, would be beneficial for implementing strategies to reduce oxidative stress levels. This study was conducted on 92 nurses from a hospital in Shahroud, a city in northeastern Iran, who were chosen at random. The data was collected through the Demographic Questionnaire, Maslach Burnout Inventory and Personality Factors Inventory. Each participant's serum markers of oxidative stress were also measured. Total antioxidant capacity (TAC) and neuroticism were found to have a negative relationship in this study. Furthermore, marital status, the ward where nurses work, the type of contract, emotional exhaustion, and depersonalization were all found to be significant predictors of malondialdehyde (MDA). Neuroticism, emotional exhaustion, and depersonalization were the most important predictors of oxidative stress levels.The results of this study suggest that some approaches to reducing oxidative stress can be implemented by identifying the factors influencing occupational burnout and also by recognizing individuals' personality traits.

Oxidative stress and soluble receptor for advanced glycation end-products play a role in the pathophysiology of delirium after cardiac surgery

Coronary-artery bypass graft (CABG) surgery is known to improve cardiac function and decrease mortality, albeit, this method of treatment is also associated with a neuropsychiatric complications including postoperative delirium. The pathophysiology of delirium after cardiac surgery remains poorly understood. Thus, the purpose of this study was to investigate whether oxidative stress reflected by decreased preoperative and postoperative plasma antioxidant activity is independently associated with delirium after cardiac surgery. The second aim was to assess whether decreased antioxidant activity is stress-related or mediated by other pathologies such as major depressive disorder (MDD), anxiety disorders, and cognitive impairment. Furthermore, the putative relationship between pre- and postoperative soluble receptor for advanced glycation end-products (sRAGE) overexpression and plasma antioxidant capacity was evaluated. The patients cognitive status was assessed 1 day preoperatively with the use of the Mini-Mental State Examination Test and the Clock Drawing Test. A diagnosis of MDD and anxiety disorders was established on the basis of DSM-5 criteria. Blood samples for antioxidant capacity and sRAGE levels were collected both preoperatively and postoperatively. The Confusion Assessment Method for the Intensive Care Unit was used within the first 5 days postoperatively to screen for a diagnosis of delirium. Postoperative delirium was diagnosed in 34% (61 of 177) of individuals. Multivariate logistic regression analysis revealed that low baseline antioxidant capacity was independently associated with postoperative delirium development. Moreover, increased risk of delirium was observed among patients with a preoperative diagnosis of MDD associated with antioxidant capacity decreased postoperatively. According to receiver operating characteristic analysis, the most optimal cutoff values of the preoperative and postoperative antioxidant capacity that predict the development of delirium were 1.72 mM and 1.89 mM, respectively. Pre- and postoperative antioxidant capacity levels were negatively correlated with postoperative sRAGE concentration (Spearman's Rank Correlation − 0.198 and − 0.158, p < 0.05, respectively). Patients with decreased preoperative antioxidant activity and those with depressive episodes complicated with lower postoperative antioxidant activity are at significantly higher risk of delirium after cardiac surgery development. sRAGE overexpression may be considered as protective mechanism against increased oxidative stress and subsequent cell damage.

Relationship between shift work and age-related macular degeneration: a cross-sectional analysis of data from the 5th Korea National Health and Nutrition Examination Survey (2010-2012)

Background

Age-related macular degeneration (AMD) is the leading cause of blindness. Shift work has well-known adverse effects on health. However, few studies have investigated the relationship between shift work and AMD. This study was conducted to investigate the relationship between shift work and AMD.

Methods

This study used aggregated data from the 2010-2012 cycles of the Korea National Health and Nutrition Examination Survey. The work schedules were classified into 2 types: day work and shift work. AMD was determined using fundus photographs. The χ² test and multiple logistic regression analysis were used to assess sex-stratified relationship between shift work and AMD.

Results

The odds ratio (OR) of AMD in male shift workers was higher (1.54 [95% confidence interval, CI: 1.01-2.36]) than that in male day workers after adjusting for covariates. After dividing into subgroups of the shift work pattern, the OR of AMD in male night shift workers was higher (1.75 [95% CI: 1.07-2.85]) than that in male day workers after adjusting for covariates. However, results of the female worker group were not significant.

Conclusions

The results of this study provide limited support for the hypothesis that shift work is related to AMD. Further prospective studies are needed to define the relationship between shift work and AMD.

A systematic review of the relationship between night shift work and oxidative stress

Night shift workers make up an essential part of the modern workforce. However, night shift workers have higher incidences of late in life diseases and earlier mortality. Night shift workers experience circadian rhythm disruption due to working overnight. Sleep disruption is thought to increase oxidative stress, defined as an imbalance of excess pro-oxidative factors and reactive oxygen species over anti-oxidative activity. Oxidative stress can damage cells, proteins and DNA and can eventually lead to varied chronic diseases such as cancer, diabetes, cardiovascular disease, Alzheimer's and dementia. This review aimed to understand whether night shift workers were at greater risk of oxidative stress. Twelve correlational studies published in 2001-2019 were included in the review that measured the levels of oxidative stress indicators from working a single night shift as well as comparisons between those who regularly work night shifts and only day shifts. All studies had evidence to support the relationship between working night shifts and increased oxidative stress indicators. Specifically, night shift work was associated with increased DNA damage, reduced DNA repair capacity, increased lipid peroxidation, higher levels of reactive oxygen species, and to a lesser extent, a reduction in antioxidant defence. These results suggest a potential link between circadian rhythm disruption in night shift workers with oxidative stress and therefore disease. However, this review is limited by having no longitudinal or experimental studies. Further research is required to infer causality. This further research is recommended to promote the long-term health of night shift workers.

Expanding the link between circadian rhythms and redox metabolism of epigenetic control

Circadian rhythms play a central role in physiological and metabolic processes. This is mostly achieved through rhythmic regulation of myriad genes via dynamic epigenome changes. Accumulating evidence indicates that oxidative stress and redox balance are under circadian control and feedback on the clock system. Circadian perturbations induce oxidative stress accumulation and disturb redox balance. Along with these changes, epigenomic landscape changes are a remarkable hallmark of clock disruption. This review aims to summarize evidence supporting the link between the circadian clock and redox metabolism, focusing on possible connections through epigenetic mechanisms.

Exposure to Radiation During Work Shifts and Working at Night Act as Occupational Stressors Alter Redox and Inflammatory Markers

BACKGROUND

Studies of breast cancer etiology suggest evidence that night shift working and occupational exposure to ionizing radiation (IR) are defined risk factors for breast cancer development. There are few studies to clarify neuroendocrine and inflammatory status and the possible consequences particularly in occupational exposure.

AIM OF THE STUDY

Our aim was to associate the redox and inflammatory biomarkers with either nightshift working or occupational radiation exposure, and to compare their levels between the two groups at Alexandria University Hospitals, Alexandria, Egypt.

METHODS

We included 150 female nurses at Alexandria University Hospitals: 50 nightshift workers, 50 radiation workers, and 50 dayshift workers as a control group (neither work nightly nor radiation workers). In morning serum sample (7 am), we measured the concentrations of serum melatonin, Cortisol, tumor necrosis factor-alpha (TNF-α) and interferon-gamma (IFN-γ) by ELISA; malondialdehyde (MDA) and total antioxidant capacity (TAC) levels colorimetrically, and C-reactive protein (C-RP) levels by turbidimetric method.

RESULTS

Nightshift workers had significantly lower levels of melatonin and TAC, and higher levels of serum inflammatory markers and cortisol, than day shift control group of workers. Workers occupationally exposed to IR had significantly higher levels of serum melatonin, MDA and inflammatory markers, lower levels of serum cortisol, and lower TAC than day shift workers.

CONCLUSION

Occupational exposure to IR and working nightly alter circulating redox and inflammatory biomarkers.

Benchmark dose estimation for coke oven emissions based on oxidative damage in Chinese exposed workers

Coke oven emissions (COEs) can cause oxidative stress of the body, which in turn induces the occupational lung disease and also increases the risk of other diseases. COEs are the major occupational hazard factors for coke oven workers. The aim of the study is to explore the influences of COEs exposure on oxidative damage and estimate the benchmark dose (BMD) of COEs. A group of 542 workers exposed to COEs and 237 healthy controls from the same city were recruited in this study. The corresponding measuring kits were used to determine the plasma biomarkers of oxidative damage level. Generalized linear models and trend tests were used to analyze the relationship between COEs exposure and biomarkers. EPA Benchmark Dose Software was performed to calculate BMD and the lower confidence limit of the benchmark dose (BMDL) of COEs exposure. A significant association was observed between COEs exposure and oxidative damage with T-AOC as a biomarker. The BMD of COEs exposure were 2.83 mg/m³ and 1.39 mg/m³ for males and females, respectively, and the corresponding BMDL were 1.47 mg/m³ and 0.75 mg/m³, respectively. Our results suggested that the exposure level of COEs below the current national occupational exposure limits (OELs) would induce oxidative damage, and the OEL of COEs based on the T-AOC damage was suggested at 0.03 mg/m³ in this study.

Recent Evidence on the Impact of Ramadan Diurnal Intermittent Fasting, Mealtime, and Circadian Rhythm on Cardiometabolic Risk: A Review

In this article, we reviewed recent data that examined the relationship of circadian rhythm, mealtime, and intermittent fasting with the risk of cardiometabolic dysfunction. We also examined the effect of their interactions on cardiometabolic risks. Furthermore, since major differences exists between Ramadan diurnal intermittent fasting compared to other forms of experimental intermittent fasting, in this article, we further restricted the discussion to Ramadan diurnal intermittent fasting. PubMed and Google Scholar databases were searched using “intermittent fasting,” “time-restricted feeding,” “fasting,” “mealtime,” “circadian rhythm,” and “cardiometabolic risk,” focusing on human studies published after 2013. Recent evidence indicates that meal timing may influence circadian rhythm, as a result, it may also directly or indirectly impact cardiometabolic risk. In humans, several studies suggested that late mealtime is related to an increased risk of poor cardiometabolic health. Nevertheless, large clinical interventional studies are required to assess causality between late mealtime and cardiometabolic morbidity. Currently, evidence indicates that Ramadan diurnal intermittent fasting has several beneficial effects that may reduce the risk of cardiometabolic disorders, such as weight reduction, improvement in lipid profile and glycemic control, reduction in proinflammatory markers, and oxidative stress. Nevertheless, several changes in daily lifestyle routine, happening during the Ramadan month, may affect the all measured markers of cardiometabolic diseases. Summarily, no definitive conclusion about the impact of Ramadan intermittent fasting on oxidative stress can be formulated. Therefore, large, well-designed studies, which control for various confounding factors are required to assess the influence of Ramadan diurnal intermittent fasting on markers of cardiometabolic risk and disorders.

Effect of Nigella sativa oil extracts on inflammatory and oxidative stress markers in Behcet's disease: A randomized, double-blind, placebo-controlled clinical trial

OBJECTIVE

Behcet's disease (BD) is a chronic inflammatory disorder characterized by recurrent oral and genital aphthous ulcers, uveitis and skin lesions. Oxidative stress and inflammation have important role in the pathogenesis of BD. The aim of this study was to assess the effect of Nigella sativa (NS) oil administration on malondialdehyde (MDA), total anti-oxidant capacity (TAC), tumor necrosis factor-α (TNF-α), IL-10 and high sensitivity C-reactive protein (hs- CRP) levels in patients with BD.

MATERIALS AND METHODS

In this randomized, double-blind and placebo-controlled clinical trial, 96 BD patients were randomly assigned to NS or placebo groups. Study groups received 1000 mg/day NS oil and placebo soft gels for 8 weeks. Serum levels of TNF-α, IL-10, hs-CRP, MDA and TAC were measured before and after treatment.

RESULTS

Eighty-nine individuals completed the study. Significant decreases in the serum levels of MDA and increases in the serum levels of TAC were found in the NS group. However, differences in the changes of MDA and TAC in the NS and placebo groups were not significant. Pre- and post-intervention changes of TNF-α, IL-10 and hs-CRP levels in the NS group were non-significant.

CONCLUSION

NS 1000 mg per day is probably not effective in reducing the inflammatory and oxidative markers in BD.

[Anxiety, sleep self-assessment, cortisol and saliva antioxidants in students with occasional experience of shift work]

AIM

To study the anxiety level, sleep self-assessment and indicators of morning and evening levels of cortisol and saliva antioxidants in students with experience of occasional shift work.

MATERIAL AND METHODS

University students (n=159) with experience of shift work were examined. Psychoemotional status was assessed using the Eysenck personality questionnaire (EPQ), Spielberger-Khanin anxiety inventory, The Taylor Manifest Anxiety Scale (Nemchin's modification). The express-questionnaire The Quality of Sleep Hygiene, the Sleep Quality scale and the scale of drowsiness were used to assess sleep. Saliva morning and evening cortisol levels (ELISA) and the total antioxidant activity (amperometric method) were determined.

RESULTS AND CONCLUSION

There was an increase in the number of respondents with higher anxiety, higher scores of psychoticism and neuroticism. According to the self-assessment of sleep, a statistically significant decrease in the quality of sleep hygiene was shown. Biochemical parameters of the saliva differed significantly only in the morning hours: the increase in cortisol and decrease in the antioxidant activity were observed. The results suggest the possibility of asymptomatic development of emotional disorders and metabolic disorders in people with occasional night shift work.

Night workers have lower levels of antioxidant defenses and higher levels of oxidative stress damage when compared to day workers

The effects of circadian misalignment and work shift on oxidative stress profile of shift workers have not been explored in the literature. The present study aimed to evaluate the role of shift work (day and night) and social jetlag - a measure of circadian misalignment - with oxidative stress markers. A cross-sectional study was performed with 79 men (21–65 years old, 27.56 ± 4.0 kg/m²) who worked the night shift (n = 37) or daytime (n = 42). The analyzed variables included anthropometric measures and determination of systemic levels of markers of oxidative damage and antioxidant defense. Social jetlag was calculated by the absolute difference between the mean sleep point on working and rest days. The night group presented higher systemic values of thiobarbituric acid reactive substances and hydrogen peroxide, and lower levels of nitrite, total antioxidant capacity, and catalase and superoxide dismutase activities in relation to the day group. However, social jetlag was not associated with oxidative stress-related biomarkers analyzed in the night group. These results suggest that the night worker has higher levels of oxidative stress damage and lower levels of antioxidant defenses, while social jetlag was not a possible responsible factor for this condition.

The association between shift work and chronic kidney disease in manual labor workers using data from the Korea National Health and Nutrition Examination Survey (KNHANES 2011-2014)

Objective

Kidneys are organs having a biological clock, and it is well known that the disruption of the circadian rhythm increases the risk of chronic kidney disease (CKD), including the decline of renal and proteinuria. Because shift work causes circadian disruption, it can directly or indirectly affect the incidence of chronic kidney disease. Therefore, the purpose of this study was to investigate the association between shift work and chronic kidney disease using a Korean representative survey dataset.

Methods

This study was comprised of 3504 manual labor workers over 20 years of age from data from the fifth and sixth Korea National Health and Nutrition Examination Survey (2011–2014). The work schedules were classified into two types: day work and shift work. The estimated glomerular filtration rate, which is the ideal marker of renal function, was estimated according to the Chronic Kidney Disease Epidemiology Collaboration creatinine equation, and chronic kidney disease was defined as urinary albumin to a creatinine ratio equal to or high than 30 mg/g and/or estimated glomerular filtration rate lower than 60 mL/min/1.73 m². The cross-tabulation analysis and multivariate logistic regression analysis were performed to confirm the association between shift work and chronic kidney disease stratified by gender.

Results

The risk of CKD showed a significant increase (odds ratio = 2.04, 95% confidence interval = 1.22, 3.41) in the female worker group. The same results were obtained after all confounding variables were adjusted (odds ratio = 2.34, 95% confidence interval = 1.35, 4.07). However, the results of the male worker group were not significant.

Conclusions

In this study using nationally representative surveys, we found that the risk of CKD was higher female workers and shift work. Future prospective cohort studies will be needed to clarify the causal relationship between shift work and CKD.

Neuroprotective action of tea polyphenols on oxidative stress-induced apoptosis through the activation of the TrkB/CREB/BDNF pathway and Keap1/Nrf2 signaling pathway in SH-SY5Y cells and mice brain

Many studies have shown that oxidative stress is a major cause of cellular injuries in a variety of human diseases including cognitive impairment. Tea polyphenols (TPs), natural plant flavonoids found in tea plant leaves, possess the bioactivity to affect the pathogenesis of several chronic diseases via antioxidant associated mechanisms. However, the possible antioxidant and neuroprotective properties of TPs in the brain of mice housed in constant darkness and in H₂O₂-stimulated SH-SY5Y cells are yet to be elucidated. In this study, pretreatment with TPs markedly attenuated H₂O₂-elicited cell viability loss and mitochondrial dysfunction, suppressed the induced apoptosis and reduced the elevated levels of intracellular ROS and H₂O₂. Additionally, TPs modulate the nuclear translocation of Nrf2 and the TrkB/CREB/BDNF signaling pathway by provoking the PI3K/AKT pathway and thus, they transcriptionally regulate the downstream expression of antioxidant enzymes including HO-1, NQO-1, and BDNF in SH-SY5Y cells. Furthermore, an in vivo study revealed that housing mice in constant darkness, simulating shift work disruption in humans, notably affects the AKT/CREB/BDNF signal pathway and the nuclear translocation of Nrf2 and its downstream phase II detoxification enzymes in brain tissue. Remarkably, TP supplementation through drinking water eliminated these changes. These results suggest that TPs possess protective effects against oxidative stress-triggered cognitive impairment, which might be a potential nutritional preventive strategy for neurodegenerative diseases implicated with oxidative stress in shift workers.

Work Intensity, Low-Grade Inflammation, and Oxidative Status: A Comparison between Office and Slaughterhouse Workers

Limited knowledge exists about the impact of physical workload on oxidative stress in different occupational categories. Thus, we aimed to investigate the oxidative and inflammatory status in employees with different physical workloads. We enrolled a total of 79 male subjects, 27 office workers (mean age 38.8 ± 9.1 years) and 52 heavy workers, in a slaughterhouse (mean age 40.8 ± 8.2 years). Fasting blood was drawn from an antecubital vein in the morning of the midweek before an 8-hour or 12-hour work shift. The antioxidative capacity was assessed measuring total antioxidant capacity (TAC), uric acid, total polyphenols (PPm), and endogenous peroxidase activity (EPA). Total peroxides (TOC), malondialdehyde (MDA), and myeloperoxidase (MPO) were analyzed as prooxidative biomarkers, and an oxidative stress index (OSI) was calculated. In addition, hsCRP, interleukin-6 (IL-6), MDA-LDL IgM antibodies, galectin-3, adrenocorticotropic hormone (ACTH), and the brain-derived neurotrophic factor (BDNF) were measured as biomarkers of chronic systemic inflammation and emotional stress. TOC (p = 0.032), TAC (p < 0.001), ACTH (p < 0.001), OSI (p = 0.011), and hsCRP (p = 0.019) were significantly increased in the heavy workers group, while EPA, BDNF (p < 0.001), and polyphenols (p = 0.004) were significantly higher in office workers. Comparison between 8 and 12 h shifts showed a worse psychological condition in heavy workers with increased levels for hsCRP (p = 0.001) and reduced concentration of BDNF (p = 0.012) compared to office workers. Oxidative stress and inflammation are induced in heavy workers and are particularly pronounced during long working hours, that is, 12-hour versus 8-hour shifts.

What time is it? Deep learning approaches for circadian rhythms

Motivation: Circadian rhythms date back to the origins of life, are found in virtually every species and every cell, and play fundamental roles in functions ranging from metabolism to cognition. Modern high-throughput technologies allow the measurement of concentrations of transcripts, metabolites and other species along the circadian cycle creating novel computational challenges and opportunities, including the problems of inferring whether a given species oscillate in circadian fashion or not, and inferring the time at which a set of measurements was taken.

Results: We first curate several large synthetic and biological time series datasets containing labels for both periodic and aperiodic signals. We then use deep learning methods to develop and train BIO_CYCLE, a system to robustly estimate which signals are periodic in high-throughput circadian experiments, producing estimates of amplitudes, periods, phases, as well as several statistical significance measures. Using the curated data, BIO_CYCLE is compared to other approaches and shown to achieve state-of-the-art performance across multiple metrics. We then use deep learning methods to develop and train BIO_CLOCK to robustly estimate the time at which a particular single-time-point transcriptomic experiment was carried. In most cases, BIO_CLOCK can reliably predict time, within approximately 1 h, using the expression levels of only a small number of core clock genes. BIO_CLOCK is shown to work reasonably well across tissue types, and often with only small degradation across conditions. BIO_CLOCK is used to annotate most mouse experiments found in the GEO database with an inferred time stamp.

Availability and Implementation: All data and software are publicly available on the CircadiOmics web portal: circadiomics.igb.uci.edu/.

Contacts:fagostin@uci.edu or pfbaldi@uci.edu

Supplementary information:Supplementary data are available at Bioinformatics online.

Circadian Rhythm Disruption and Subsequent Neurological Disorders in Night-Shift Workers

A large number of people in highly industrialized society are employed in night-shift work. Night-shift work interrupts the 24-hour daily cycle known as the circadian rhythm, as well as melatonin synthesis. These disruptions can make the body susceptible to oxidative stress and neural damage. In this regard, it is recommended that employees avoid long-term exposure to night-shift work.

Remodeling of the cycling transcriptome of the oyster Crassostrea gigas by the harmful algae Alexandrium minutum

As a marine organism, the oyster Crassostrea gigas inhabits a complex biotope governed by interactions between the moon and the sun cycles. We used next-generation sequencing to investigate temporal regulation of oysters under light/dark entrainment and the impact of harmful algal exposure. We found that ≈6% of the gills' transcriptome exhibits circadian expression, characterized by a nocturnal and bimodal pattern. Surprisingly, a higher number of ultradian transcripts were also detected under solely circadian entrainment. The results showed that a bloom of Alexandrium minutum generated a remodeling of the bivalve's temporal structure, characterized by a loss of oscillations, a genesis of de novo oscillating transcripts, and a switch in the period of oscillations. These findings provide unprecedented insights into the diurnal landscape of the oyster's transcriptome and pleiotropic remodeling due to toxic algae exposure, revealing the intrinsic plasticity of the cycling transcriptome in oysters.

Clock Regulation of Metabolites Reveals Coupling between Transcription and Metabolism

The intricate connection between the circadian clock and metabolism remains poorly understood. We used high temporal resolution metabolite profiling to explore clock regulation of mouse liver and cell-autonomous metabolism. In liver, ∼50% of metabolites were circadian, with enrichment of nucleotide, amino acid, and methylation pathways. In U2 OS cells, 28% were circadian, including amino acids and NAD biosynthesis metabolites. Eighteen metabolites oscillated in both systems and a subset of these in primary hepatocytes. These 18 metabolites were enriched in methylation and amino acid pathways. To assess clock dependence of these rhythms, we used genetic perturbation. BMAL1 knockdown diminished metabolite rhythms, while CRY1 or CRY2 perturbation generally shortened or lengthened rhythms, respectively. Surprisingly, CRY1 knockdown induced 8 hr rhythms in amino acid, methylation, and vitamin metabolites, decoupling metabolite from transcriptional rhythms, with potential impact on nutrient sensing in vivo. These results provide the first comprehensive views of circadian liver and cell-autonomous metabolism.

Tea polyphenols ameliorate hydrogen peroxide- and constant darkness-triggered oxidative stress via modulating the Keap1/Nrf2 transcriptional signaling pathway in HepG2 cells and mice liver

Tea polyphenols alleviate oxidative stressviamodulating the Keap1/Nrf2 transcriptional signaling pathway in HepG2 cells and the liver of mice kept in constant darkness.

Deciphering the Duality of Clock and Growth Metabolism in a Cell Autonomous System Using NMR Profiling of the Secretome

Oscillations in circadian metabolism are crucial to the well being of organism. Our understanding of metabolic rhythms has been greatly enhanced by recent advances in high-throughput systems biology experimental techniques and data analysis. In an in vitro setting, metabolite rhythms can be measured by time-dependent sampling over an experimental period spanning one or more days at sufficent resolution to elucidate rhythms. We hypothesized that cellular metabolic effects over such a time course would be influenced by both oscillatory and circadian-independent cell metabolic effects. Here we use nuclear magnetic resonance (NMR) spectroscopy-based metabolic profiling of mammalian cell culture media of synchronized U2 OS cells containing an intact transcriptional clock. The experiment was conducted over 48 h, typical for circadian biology studies, and samples collected at 2 h resolution to unravel such non-oscillatory effects. Our data suggest specific metabolic activities exist that change continuously over time in this settting and we demonstrate that the non-oscillatory effects are generally monotonic and possible to model with multivariate regression. Deconvolution of such non-circadian persistent changes are of paramount importance to consider while studying circadian metabolic oscillations.

Contribution of Inflammation, Oxidative Stress, and Antioxidants to the Relationship between Sleep Duration and Cardiometabolic Health

OBJECTIVES

To explore the interrelationship and mediating effect of factors that are beneficial (i.e., antioxidants) and harmful (i.e., inflammation and oxidative stress) to the relationship between sleep and cardiometabolic health.

DESIGN

Cross-sectional data from the 2005-2006 National Health and Nutrition Examination Survey.

SETTING

Nationally representative population sample from the US.

PARTICIPANTS

Age ≥ 20 y with sleep data; final analytical sample of n = 2,079.

INTERVENTIONS

N/A.

MEASUREMENTS AND RESULTS

Metabolic syndrome was classified according to the Joint Interim Statement, and sleep duration was categorized as very short, short, adequate, and long sleepers (≤ 4, 5-6, 7-8, and ≥ 9 h per night, respectively). The indirect mediation effect was quantified as large (≥ 0.25), moderate (≥ 0.09), modest (≥ 0.01), and weak (< 0.01). In general, inflammation was above the current clinical reference range across all sleep duration categories, whereas oxidative stress was elevated among short and very short sleepers. Select sleep duration- cardiometabolic health relationships were mediated by C-reactive protein (CRP), γ-glutamyl transferase (GGT), carotenoids, uric acid, and vitamins C and D, and were moderated by sex. Specifically, moderate-to-large indirect mediation by GGT, carotenoids, uric acid, and vitamin D were found for sleep duration-waist circumference and -systolic blood pressure relationships, whereas vitamin C was a moderate mediator of the sleep duration-diastolic blood pressure relationship.

CONCLUSIONS

Several factors related to inflammation, oxidative stress, and antioxidant status were found to lie on the casual pathway of the sleep duration-cardiometabolic health relationship. Further longitudinal studies are needed to confirm our results.

Interdisciplinary therapy changes superoxide dismutase activity and adiponectin in obese adolescents: a randomised controlled trial

The objective of this study is to evaluate the effect of interdisciplinary therapy in the parameters of the oxidative stress and the anti-inflammatory responses of obese adolescents. We selected 57 participants, who were randomly divided into 2 groups: interdisciplinary therapy group and a control group. After 6 months of intervention, 17 participants of the interdisciplinary therapy group and 8 of the control group returned for re-evaluation. The interdisciplinary therapy group participated in a treatment with 4 weekly sessions of exercise, a weekly group therapy session and a weekly nutritional education session. Blood parameters of oxidative stress and anti-inflammatory response were evaluated. The results demonstrated that there were significant increases in the interdisciplinary therapy group for superoxide dismutase activity (6.56 ± 3.22 to 11.40 ± 7.49) and ferric-reducing antioxidant potential concentration (532.91 ± 106.48 to 573.25 ± 112.57), although adiponectin levels did not reduce (40.9 ± 29.34 to 49.05 ± 41.22). A significant decrease in nitrite levels was also found (14.23 ± 8.48 to 11.45 ± 6.05). In the control group, significant reduction was found in adiponectin (31.56 ± 18.88 to 18.01 ± 11.66). This study suggests that interdisciplinary therapy for 6 months was effective in improving the anti-inflammatory responses and the antioxidant defences in obese adolescents.

The pervasiveness and plasticity of circadian oscillations: the coupled circadian-oscillators framework

MOTIVATION

Circadian oscillations have been observed in animals, plants, fungi and cyanobacteria and play a fundamental role in coordinating the homeostasis and behavior of biological systems. Genetically encoded molecular clocks found in nearly every cell, based on negative transcription/translation feedback loops and involving only a dozen genes, play a central role in maintaining these oscillations. However, high-throughput gene expression experiments reveal that in a typical tissue, a much larger fraction ([Formula: see text]) of all transcripts oscillate with the day-night cycle and the oscillating species vary with tissue type suggesting that perhaps a much larger fraction of all transcripts, and perhaps also other molecular species, may bear the potential for circadian oscillations.

RESULTS

To better quantify the pervasiveness and plasticity of circadian oscillations, we conduct the first large-scale analysis aggregating the results of 18 circadian transcriptomic studies and 10 circadian metabolomic studies conducted in mice using different tissues and under different conditions. We find that over half of protein coding genes in the cell can produce transcripts that are circadian in at least one set of conditions and similarly for measured metabolites. Genetic or environmental perturbations can disrupt existing oscillations by changing their amplitudes and phases, suppressing them or giving rise to novel circadian oscillations. The oscillating species and their oscillations provide a characteristic signature of the physiological state of the corresponding cell/tissue. Molecular networks comprise many oscillator loops that have been sculpted by evolution over two trillion day-night cycles to have intrinsic circadian frequency. These oscillating loops are coupled by shared nodes in a large network of coupled circadian oscillators where the clock genes form a major hub. Cells can program and re-program their circadian repertoire through epigenetic and other mechanisms.

AVAILABILITY AND IMPLEMENTATION

High-resolution and tissue/condition specific circadian data and networks available at http://circadiomics.igb.uci.edu.

CONTACT

pfbaldi@ics.uci.edu

SUPPLEMENTARY INFORMATION

Supplementary data are available at Bioinformatics online.

Oxidative Stress and Depression among Male Shift Workers in Shahid Tondgouyan Refinery

OBJECTIVE

The aim of this study was to determine the oxidative stress; serum level of Total Antioxidant Capacity (TAC)and Malondialdehyde (MDA) level and the depression score among the depressed rotational shift workers in Shahid Tondgouyan Refinery in Tehran (Iran).

METHODS

A cross-sectional study was conducted among all the 189 shift workers in Shahid Tondgouyan oil refinery who were eligible to participate in the study. They did not take any antidepressants for two months or any supplements for two weeks prior to the study entry. Written consent was obtained from the participants. 21- Item Beck Depression Inventory was used to measure the depression level. Furthermore, body weight, height and systolic and diastolic blood pressure were collected from all the participants. The levels of Total Antioxidant Capacity (TAC) and Malondialdehyde (MDA) were measured by 8 ml fasting blood sample. MDA was determined by thiobarbituric acid reaction. Serum total antioxidants were measured using the spectrophotometric ABTS. In the ABTS test, 2,2'-azinobis (3-ethylbenzthiazoline-6-acid) (ABTS) is converted into its radical cation (ABTS•+) by addition of sodium persulphate. This blue-green radical cation absorbs light at 734 nm. ABTS•+ is reactive towards most antioxidants. Descriptive statistics, ANOVA, ANCOVA and regression tests and correlation were used to analyze the data using SPSS software version 16.

RESULTS

The age of the participants ranged from 21 to 52 years. The mean age of the participants was 30.58 year (±6.97yr). Of all the participants, 28% (n= 53) had no depression symptoms (depression score between 0 and 9), 65.1% (n=123) were categorized as having mild depression (depression score between 10 and 18) and 6.9% (n=13) were categorized as having moderate depression (depression score between 19 and 29). The participants' BMI ranged from 15.9 to 34.3; the mean BMI of the participants was 24.82 kg/m(2) (+ 3.81 kg/m(2)). The mean of the serum TAC level was 2.51 (± 0.56) mg/dl, and the mean serum MDA level was 3.67(± 1.08) μmol/l. There was a significant difference in the mean TAC concentration between the non-depressed group and the group with mild depression (p=0.029).

CONCLUSION

Depression was associated with reduced mean TAC concentration and an increase in MDA level. There was a linear relationship between the depression score and shift work experience among the rotational shift workers, which showed a high level of stress and depression among the shift-workers.

Association among Working Hours, Occupational Stress, and Presenteeism among Wage Workers: Results from the Second Korean Working Conditions Survey

Objectives

The purpose of the present study was to identify the association between presenteeism and long working hours, shiftwork, and occupational stress using representative national survey data on Korean workers.

Methods

We analyzed data from the second Korean Working Conditions Survey (KWCS), which was conducted in 2010, in which a total of 6,220 wage workers were analyzed. The study population included the economically active population aged above 15 years, and living in the Republic of Korea. We used the chi-squared test and multivariate logistic regression to test the statistical association between presenteeism and working hours, shiftwork, and occupational stress.

Results

Approximately 19% of the workers experienced presenteeism during the previous 12 months. Women had higher rates of presenteeism than men. We found a statistically significant dose–response relationship between working hours and presenteeism. Shift workers had a slightly higher rate of presenteeism than non-shift workers, but the difference was not statistically significant. Occupational stress, such as high job demand, lack of rewards, and inadequate social support, had a significant association with presenteeism.

Conclusions

The present study suggests that long working hours and occupational stress are significantly related to presenteeism.

Modulation of nuclear receptor function by cellular redox poise

Nuclear receptors (NRs) are ligand-responsive transcription factors involved in diverse cellular processes ranging from metabolism to circadian rhythms. This review focuses on NRs that contain redox-active thiol groups, a common feature within the superfamily. We will begin by describing NRs, how they regulate various cellular processes and how binding ligands, corepressors and/or coactivators modulate their activity. We will then describe the general area of redox regulation, especially as it pertains to thiol-disulfide interconversion and the cellular systems that respond to and govern this redox equilibrium. Lastly, we will discuss specific examples of NRs whose activities are regulated by redox-active thiols. Glucocorticoid, estrogen, and the heme-responsive receptor, Rev-erb, will be described in the most detail as they exhibit archetypal redox regulatory mechanisms.

The influence of shift work on cognitive functions and oxidative stress

Shift work influences health, performance, activity, and social relationships, and it causes impairment in cognitive functions. In this study, we investigated the effects of shift work on participants' cognitive functions in terms of memory, attention, and learning, and we measured the effects on oxidative stress. Additionally, we investigated whether there were significant relationships between cognitive functions and whole blood oxidant/antioxidant status of participants. A total of 90 health care workers participated in the study, of whom 45 subjects were night-shift workers. Neuropsychological tests were administered to the participants to assess cognitive function, and blood samples were taken to detect total antioxidant capacity and total oxidant status at 08:00. Differences in anxiety, depression, and chronotype characteristics between shift work groups were not significant. Shift workers achieved significantly lower scores on verbal memory, attention-concentration, and the digit span forward sub-scales of the Wechsler Memory Scale-Revised (WMS-R), as well as on the immediate memory and total learning sub-scales of the Auditory Verbal Learning Test (AVLT). Oxidative stress parameters were significantly associated with some types of cognitive function, including attention-concentration, recognition, and long-term memory. These findings suggest that night shift work may result in significantly poorer cognitive performance, particularly working memory.

Long-term day-and-night rotating shift work poses a barrier to the normalization of alanine transaminase

To evaluate the impact of day-and-night rotating shift work (RSW) on liver health, we performed a retrospective analysis of the association between long-term RSW exposure and the normalization of plasma alanine transaminase (ALT) levels over a five-year period. The data from physical examinations, blood tests, abdominal sonographic examinations, personal histories, and occupational records were collected from a cohort of workers in a semiconductor manufacturing company. The sample population was divided into three subgroups for analysis, according to self-reported shift work status over the five-year interval: persistent daytime workers, workers exposed intermittently to RSW (i-RSW), and workers exposed persistently to RSW (p-RSW). Records were analyzed for 1196 male workers with an initial mean age of 32.5 years (SD 6.0 years), of whom 821 (68.7%) were identified as rotating shift workers, including 374 i-RSW (31.3%) and 447 p-RSW workers (37.4%). At the beginning of the follow-up, 275 were found to have elevated ALT (e-ALT): 25.1% daytime workers, 23.0% i-RSW workers, and 21.3% p-RSW workers (p = 0.098). Of those with e-ALT at the beginning, 101 workers showed normalized serum ALT levels at the end of five-year follow-up: 40 (10.7%) of 375 daytime workers, 32 (8.6%) of 374 i-RSW workers, and 29 (6.5%) of 447 p-RSW workers (p = 0.016). Compared with the workers having persistent e-ALT at the end of follow-up, the workers normalized serum ALT levels had significantly lesser exposures to RSW during follow-up. By performing multivariate logistic regression analyses, and comparing with the persistent daytime co-workers, after controlling for confounding variables (age, occupational factors, educational levels, lifestyle factors, metabolic syndrome, hepatovirus infection, and fatty liver), analysis indicated that the workers exposed to p-RSW were 46% less likely (OR, 0.54; 95% CI, 0.30-0.95; p = 0.03) to attain normal ALT levels within a five-year interval. These observations demonstrate that persistent day-and-night RSW pose a vigorous obstacle to the normalization of e-ALT among workers with preexisting abnormal liver function. We suggest that workers and managers approach with caution the consideration of assigning or accepting long-term day-and-night RSW when an employee health screening shows evidence of abnormal liver function.

Reprogramming of the circadian clock by nutritional challenge

Circadian rhythms and cellular metabolism are intimately linked. Here, we reveal that a high-fat diet (HFD) generates a profound reorganization of specific metabolic pathways, leading to widespread remodeling of the liver clock. Strikingly, in addition to disrupting the normal circadian cycle, HFD causes an unexpectedly large-scale genesis of de novo oscillating transcripts, resulting in reorganization of the coordinated oscillations between coherent transcripts and metabolites. The mechanisms underlying this reprogramming involve both the impairment of CLOCK:BMAL1 chromatin recruitment and a pronounced cyclic activation of surrogate pathways through the transcriptional regulator PPARγ. Finally, we demonstrate that it is specifically the nutritional challenge, and not the development of obesity, that causes the reprogramming of the clock and that the effects of the diet on the clock are reversible.

Total antioxidant capacity and malondialdehyde in depressive rotational shift workers

Shift work is associated with sleep deprivation, occupational stress, and increased risk of depression. Depressed patients show increased oxidative stress. During excessive oxidative stress, Malondialdehyde (MDA) increases and total antioxidant capacity (TAC) decreases in body. This cross-sectional study was conducted to determine the serum level of TAC and MDA among depressed rotational shift workers in Shahid Tondooyan Tehran Oil Refinery. 21-item Beck Depression Inventory was used to measure depression level. The level of TAC and MDA was measured by 8 mL fasting blood sample. MDA was determined by thiobarbituric acid reaction. Serum total antioxidants were measured using the ABTS. Results of this study showed that TAC mean and standard deviation concentration was 2.451 (±0.536) mg/dL and MDA was 3.725 (±1.098) mic·mol/L, and mean and standard deviation of depression score and BMI were 14.07 (±3.84) and 24.92 (±3.65) kg/m², respectively. Depression score had a positive correlation with rotational shift work experience and work experience (r = 0.218 and r = 0.212), respectively, (P < 0.05).

Evaluation of oxidative stress parameters and metabolic activities of nurses working day and night shifts

The aim of this study was to evaluate the oxidative stress and metabolic activities of nurses working day and night shifts. Intensive care unit (ICU) (n=70) and ordinary service (OS) nurses (n=70) were enrolled in the study. Just before and the end of the shifts, blood samples were obtained to measure the participants' oxidative stress parameters. Metabolic activities were analyzed using the SenseWear Armband. Oxidative stress parameters were increased at the end of the shifts for all OS and ICU nurses compared to the beginning of the shifts. Compared to the OS nurses, the ICU nurses' TAS, TOS, and OSI levels were not significantly different at the end of the day and night shifts. The metabolic activities of the OS and ICU nurses were found to be similar. As a result, the OS and ICU nurses' oxidative stress parameters and metabolic activities were not different, and all of the nurses experienced similar effects from both the day and night shifts.

Persistent rotating shift work exposure is a tough second hit contributing to abnormal liver function among on-site workers having sonographic fatty liver

To investigate the relationship between elevated serum alanine-transaminase (e-ALT) and persistent rotating shift work (p-RSW) among employees with sonographic fatty liver (SFL), the authors performed a retrospective analysis on a cohort of electronics manufacturing workers. The records of 758 workers (507 men, 251 women) with initially normal ALT and a mean age of 32.9 years were analyzed. A total of 109 workers (14.4%) developed e-ALT after 5 years. Compared with those having neither initial SFL nor p-RSW exposure, multivariate analysis indicated that employees who had initial SFL but without p-RSW finally had a higher risk (odds ratio = 2.9; 95% confidence interval [CI] = 1.7-5.1) for developing e-ALT; workers with baseline SFL plus p-RSW had a 3.7-fold increased risk (95% CI = 1.8-7.5). SFL poses a conspicuous risk for the development of e-ALT, and persistent p-RSW exposure significantly aggravates the development of e-ALT among on-site workers with preexisting SFL.

Control of sleep and wakefulness

This review summarizes the brain mechanisms controlling sleep and wakefulness. Wakefulness promoting systems cause low-voltage, fast activity in the electroencephalogram (EEG). Multiple interacting neurotransmitter systems in the brain stem, hypothalamus, and basal forebrain converge onto common effector systems in the thalamus and cortex. Sleep results from the inhibition of wake-promoting systems by homeostatic sleep factors such as adenosine and nitric oxide and GABAergic neurons in the preoptic area of the hypothalamus, resulting in large-amplitude, slow EEG oscillations. Local, activity-dependent factors modulate the amplitude and frequency of cortical slow oscillations. Non-rapid-eye-movement (NREM) sleep results in conservation of brain energy and facilitates memory consolidation through the modulation of synaptic weights. Rapid-eye-movement (REM) sleep results from the interaction of brain stem cholinergic, aminergic, and GABAergic neurons which control the activity of glutamatergic reticular formation neurons leading to REM sleep phenomena such as muscle atonia, REMs, dreaming, and cortical activation. Strong activation of limbic regions during REM sleep suggests a role in regulation of emotion. Genetic studies suggest that brain mechanisms controlling waking and NREM sleep are strongly conserved throughout evolution, underscoring their enormous importance for brain function. Sleep disruption interferes with the normal restorative functions of NREM and REM sleep, resulting in disruptions of breathing and cardiovascular function, changes in emotional reactivity, and cognitive impairments in attention, memory, and decision making.

Coordination of the transcriptome and metabolome by the circadian clock

The circadian clock governs a large array of physiological functions through the transcriptional control of a significant fraction of the genome. Disruption of the clock leads to metabolic disorders, including obesity and diabetes. As food is a potent zeitgeber (ZT) for peripheral clocks, metabolites are implicated as cellular transducers of circadian time for tissues such as the liver. From a comprehensive dataset of over 500 metabolites identified by mass spectrometry, we reveal the coordinate clock-controlled oscillation of many metabolites, including those within the amino acid and carbohydrate metabolic pathways as well as the lipid, nucleotide, and xenobiotic metabolic pathways. Using computational modeling, we present evidence of synergistic nodes between the circadian transcriptome and specific metabolic pathways. Validation of these nodes reveals that diverse metabolic pathways, including the uracil salvage pathway, oscillate in a circadian fashion and in a CLOCK-dependent manner. This integrated map illustrates the coherence within the circadian metabolome, transcriptome, and proteome and how these are connected through specific nodes that operate in concert to achieve metabolic homeostasis.