New perspectives on the role of melatonin in human sleep, circadian rhythms and their regulation

The role of nitric oxide and neuroendocrine system in pain generation

Previous studies have indicated a complex interplay between the nitric oxide (NO) pain signaling pathways and hormonal signaling pathways in the body. This article delineates the role of nitric oxide signaling in neuropathic and inflammatory pain generation and subsequently discusses how the neuroendocrine system is involved in pain generation. Hormonal systems including the hypothalamic-pituitary axis (HPA) generation of cortisol, the renin-angiotensin-aldosterone system, calcitonin, melatonin, and sex hormones could potentially contribute to the generation of nitric oxide involved in the sensation of pain. Further research is necessary to clarify this relationship and may reveal therapeutic targets involving NO signaling that alleviate neuropathic and inflammatory pain.

Zygotic Exposure to Venlafaxine Disrupts the Circadian Locomotor Activity Behaviour in Zebrafish Larvae

The antidepressant venlafaxine, a selective serotonin and norepinephrine reuptake inhibitor, is commonly prescribed to treat major depressive disorder and is found at high concentrations in the aquatic environment. Concerns have been raised related to the health of aquatic organisms in response to this nontargeted pharmaceutical exposure. For instance, we previously demonstrated that exposure to venlafaxine perturbs neurodevelopment, leading to behavioural alterations in zebrafish (Danio rerio). We also observed disruption in serotonin expression in the pineal and raphe, regions critical in regulating circadian rhythms, leading us to hypothesize that zygotic exposure to venlafaxine disrupts the circadian locomotor rhythm in larval zebrafish. To test this, we microinjected zebrafish embryos with venlafaxine (1 or 10 ng) and recorded the locomotor activity in 5-day-old larvae over a 24-h period. Venlafaxine deposition reduced larval locomotor activity during the light phase, but not during the dark phase of the diurnal cycle. The melatonin levels were higher in the dark compared to during the light photoperiod and this was not affected by embryonic venlafaxine deposition. Venlafaxine exposure also did not affect the transcript abundance of clock genes, including clock1a, bmal2, cry1a and per2, which showed a clear day/night rhythmicity. A notable finding was that exposure to luzindole, a melatonin receptor antagonist, decreased the locomotor activity in the control group in light, whereas the activity was higher in larvae raised from the venlafaxine-deposited embryos. Overall, zygotic exposure to venlafaxine disrupts the locomotor activity of larval zebrafish fish during the day, demonstrating the capacity of antidepressants to disrupt the circadian rhythms in behaviour. Our results suggest that disruption in melatonin signalling may be playing a role in the venlafaxine impact on circadian behaviour, but further investigation is required to elucidate the possible mechanisms in larval zebrafish.

Mechanism of action of the Banxia-Xiakucao herb pair in sleep deprivation: New comprehensive evidence from network pharmacology, transcriptomics and molecular biology experiments

ETHNOPHARMACOLOGICAL RELEVANCE

Chinese herb pairs are the most basic and compressed examples of Chinese herbal combinations and can be used to effectively explain the fundamental concepts of traditional Chinese medicine prescriptions. These pairings have gained significant interest due to their subtle therapeutic benefits, minimal side effects, and efficacy in treating complicated chronic conditions. The Banxia-Xiakucao Chinese herb pair (BXHP) consists of Pinellia ternata (Thunb.) Breit. (Banxia) and Prunella vulgaris L. (Xiakucao). This formula was documented in The Medical Classic of the Yellow Emperor approximately 2000 years ago，and clinical research has demonstrated that BXHP effectively treats insomnia AIM OF THE STUDY: This study aimed to evaluate the efficacy and therapeutic mechanism of the BXHP through a comprehensive strategy involving network pharmacology, molecular docking, transcriptomics, and molecular biology experimental validation.

MATERIALS AND METHODS

The composition of BXHP was characterized using the UPLC-Q-TOF-MS. The active compounds were screened to find drug-likeness compounds by analyzing the ADME data. To predict the molecular mechanism of BXHP in sleep deprivation (SD) by network pharmacology and molecular docking. We established a rat model of SD and the in vivo efficacy of BXHP was verified through the pentobarbital sodium righting reflex test, behavioral assays, enzyme-linked immunosorbent assay, transmission electron microscopy, HE staining, and Nissl staining, and the underlying molecular mechanism of BXHP in SD was revealed through transcriptomic and bioinformatic analyses in conjunction with quantitative real-time PCR, Western blot, and immunofluorescence staining.

RESULTS

In the present study, we showed for the first time that BXHP reduced sleep latency, prolongs sleep duration, and improves anxiety; lowered serum CORT, IL6, TNF-α and MDA levels; decreased hypothalamic Glu levels; and elevated hypothalamic GABA and 5-HT levels in SD rats. We found 16 active compounds that acted on 583 targets, 145 of which are related to SD. By modularly dissecting the PPI network, we discovered three critical targets, Akt1, CREB1, and PRKACA, all of which play important roles in the effects of BXHP on SD. Molecular docking resulted in the identification of 16 active compounds that strongly bind to key targets. The results of GO and KEGG enrichment analyses of network pharmacology and transcriptomics focused on both the regulation of circadian rhythm and the cAMP signaling pathway, which strongly demonstrated that BXHP affects SD via the cAMP-PKA-CREB-Circadian rhythm pathway. Molecular biology experiments verified this hypothesis. Following BXHP administration, PKA and CREB phosphorylation levels were elevated in SD rats, the cAMP-PKA-CREB signaling pathway was activated, the expression levels of the biological clock genes CLOCK, p-BMAL1/BMAL1, and PER3 were increased, and the rhythmicity of the biological clock was improved.

CONCLUSIONS

The active compounds in BXHP can activate the cAMP-PKA-CREB-Circadian rhythm pathway, improve the rhythmicity of the biological clock, promote sleep and ameliorate anxiety, which suggests that BXHP improves SD through a multicomponent, multitarget, multipathway mechanism. This study is important for the development of herbal medicines and clinical therapies for improving sleep deprivation.

Long-lasting effects of disturbing the circadian rhythm or sleep in adolescence

Circadian rhythms are endogenous, near 24-hour rhythms that regulate a multitude of biological and behavioral processes across the diurnal cycle in most organisms. Over the lifespan, a bell curve pattern emerges in circadian phase preference (i.e. chronotype), with children and adults generally preferring to wake earlier and fall asleep earlier, and adolescents and young adults preferring to wake later and fall asleep later than their adult counterparts. This well-defined shift speaks to the variability of circadian rhythmicity over the lifespan and the changing needs and demands of the brain as an organism develops, particularly in the adolescent period. Indeed, adolescence is known to be a critical period of development during which dramatic neuroanatomical changes are occurring to allow for improved decision-making. Due to the large amount of re-structuring occurring in the adolescent brain, circadian disruptions during this period could have adverse consequences that persist across the lifespan. While the detrimental effects of circadian disruptions in adults have been characterized in depth, few studies have longitudinally assessed the potential long-term impacts of circadian disruptions during adolescence. Here, we will review the evidence that disruptions in circadian rhythmicity during adolescence have effects that persist into adulthood. As biological and social time often conflict in modern society, with school start times misaligned with adolescents' endogenous rhythms, it is critical to understand the long-term impacts of disrupted circadian rhythmicity in adolescence.

Exogenous melatonin's effect on salivary cortisol and amylase: A randomized controlled trial

This study aimed to examine the effect of acute exogenous melatonin administration on salivary cortisol and alpha-amylase (sCort and sAA) as representatives of the HPA axis and the sympathetic nervous system, respectively. A single-dose prolonged-release melatonin (2 mg) or a placebo tablet was given to healthy volunteers (n = 64) at 20:00 h in a crossover design. The saliva was collected at six time points (20:00, 21:00, awakening, 30 min after awakening, 10:00, and 12:00 h) and was measured for sCort, sAA, and salivary melatonin (sMT) levels. Pulse rates and sleep parameters were also collected. Melatonin was effective in improving sleep onset latency by 7:04 min (p = .037) and increasing total sleep time by 24 min (p = .006). Participants with poor baseline sleep quality responded more strongly to melatonin than participants with normal baseline sleep quality as they reported more satisfaction in having adequate sleep (p = .017). Melatonin administration resulted in higher sCort levels at awakening time point (p = .023) and a tendency of lower sAA levels but these were not significant. Melatonin ingestion at 20:00 h resulted in a marked increase in sMT levels at 21:00 h and remained higher than baseline up to at least 10:00 h (p < .001). Melatonin increases sCort levels at certain time point with a tendency to lower sAA levels. These opposing effects of melatonin suggested a complex interplay between melatonin and these biomarkers. Also, the results confirmed the positive acute effect of a single-dose melatonin on sleep quality.

Bipolar Disorder, Circadian Rhythm and Clock Genes

Sleep disturbance and abnormal circadian rhythm might be closely related to bipolar disorder. Several studies involving disturbed sleep/wake cycle, changes in rhythms such as melatonin and cortisol, clock genes, and circadian preference have shown the relationship between bipolar disorder and circadian rhythm. The results differed across different studies. In some studies, a delay in the circadian rhythm was observed in the depressive episode and advanced circadian rhythm was observed during the manic episode. In other studies, a delay in circadian rhythm was observed independent of mood episodes. Accordingly, circadian rhythm disorder was proposed as a trait marker for bipolar disorder. The altered circadian rhythm may represent a pathological mechanism that contributes to the mood episodes. However, a prospective cohort study is needed for further clarification.

Insights into the mechanical microenvironment within the cartilaginous endplate: An emerging role in maintaining disc homeostasis and normal function

Biomechanical factors are strongly linked with the emergence and development of intervertebral disc degeneration (IVDD). The intervertebral disc (IVD), as a unique enclosed biomechanical structure, exhibits distinct mechanical properties within its substructures. Damage to the mechanical performance of any substructure can disrupt the overall mechanical function of the IVD. Endplate degeneration serves as a significant precursor to IVDD. The endplate (EP) structure, especially the cartilaginous endplate (CEP), serves as a conduit for nutrient and metabolite transport in the IVD. It is inevitably influenced by its nutritional environment, mechanical loading, cytokines and extracellular components. Currently, reports on strategies targeting the CEP for the prevention and treatment of IVDD are scarce. This is due to two primary reasons: first, limited knowledge of the biomechanical microenvironment surrounding the degenerated CEP cells; and second, innovative biological treatment strategies, such as implanting active cells (disc or mesenchymal stem cells) or modulating natural cell activity through the addition of therapeutic factors or genes to treat IVDD often overlook a critical aspect-the restoration of the nutrient supply function and mechanical microenvironment of the endplate. Therefore, restoring the healthy structure of the CEP and maintaining a stable mechanical microenvironment within the EP are crucial for the prevention of IVDD and the repair of degenerated IVDs. We present a comprehensive literature review on the mechanical microenvironment characteristics of cartilage endplates and their associated mechanical signaling pathways. Our aim is to provide valuable insights into the development and implementation of strategies to prevent IVDD by delaying or reversing CEP degeneration.

Delineating molecular regulatory network of meat quality of longissimus dorsi indicated by transcriptomic, proteomic, and metabolomics analysis in rabbit

This study aims to investigate the potential regulatory network responsible for the meat quality using multi-omics to help developing better varieties. Slaughter performance and meat quality of Shuxing No.1 rabbit outperformed IRA rabbit according to the tested rabbit parameters. Differentially expressed genes (DEGs) and differentially abundance proteins (DAPs) were involved in meat quality-related pathways, such as PI3K - Akt and MAPK signaling pathways. Only SMTNL1 and PM20D2 shared between DEGs and DAPs. Olfactory-sensitive undecanal, a differentially abundant metabolite (DAM) in volatilomics (vDAMs), correlated with all of the remaining 11 vDAMs, and most of 12 vDAMs were associated with amino acid metabolism. Integration revealed that 829 DEGs/DAPs were associated with 15 DAMs in four KEGG pathways, such as melatonin (a DAM in widely targeted metabolomics) was significantly positively correlated with ALDH and negatively correlated with RAB3D and CAT in the tryptophan metabolism pathway. This study sheds light on the potential mechanisms that contribute to the improved meat quality and flavor. SIGNIFICANCE: Shuxing No.1 rabbit is a new breed of meat rabbit in the Chinese market. In meat marketing, meat quality usually determines the purchase intention of consumers. Determining the biological and molecular mechanisms of meat quality in meat rabbit is essential for developing strategies to improve meat quality. According to the tested rabbit parameters, this study ascertained that the slaughter performance and meat quality of Shuxing No.1 rabbit surpasses that of IRA rabbit. The present study profiled the transcriptome, proteome, widely targeted metabolome, and volatilome of longissimus dorsi from Shuxing No.1 rabbit and IRA rabbit. The study found that meat quality and flavor-related tryptophan metabolism pathway is enriched with many DEGs/DAPs (including ALDH, RAB3D, and CAT), as well as a DAM, melatonin. This study sheds light on the potential mechanisms that contribute to the improved meat quality and flavor.

The Vital Role of Melatonin and Its Metabolites in the Neuroprotection and Retardation of Brain Aging

While primarily produced in the pineal gland, melatonin's influence goes beyond its well-known role in regulating sleep, nighttime metabolism, and circadian rhythms, in the field of chronobiology. A plethora of new data demonstrates melatonin to be a very powerful molecule, being a potent ROS/RNS scavenger with anti-inflammatory, immunoregulatory, and oncostatic properties. Melatonin and its metabolites exert multiple beneficial effects in cutaneous and systemic aging. This review is focused on the neuroprotective role of melatonin during aging. Melatonin has an anti-aging capacity, retarding the rate of healthy brain aging and the development of age-related neurodegenerative diseases, such as Alzheimer's disease, Parkinson's disease, Huntington's disease, multiple sclerosis, amyotrophic lateral sclerosis, etc. Melatonin, as well as its metabolites, N1-acetyl-N2-formyl-5-methoxykynuramine (AFMK) and N1-acetyl-5-methoxykynuramine (AMK), can reduce oxidative brain damage by shielding mitochondria from dysfunction during the aging process. Melatonin could also be implicated in the treatment of neurodegenerative conditions, by modifying their characteristic low-grade neuroinflammation. It can either prevent the initiation of inflammatory responses or attenuate the ongoing inflammation. Drawing on the current knowledge, this review discusses the potential benefits of melatonin supplementation in preventing and managing cognitive impairment and neurodegenerative diseases.

Simulated pharmacokinetics of inhaled caffeine and melatonin from existing products indicate the lack of dosimetric considerations

Numerous commercially available inhalable products claim to improve sleep-wake cycle-related target indications by delivering a wide variety of chemicals like caffeine and melatonin. The resulting exposure-responses from inhaling different doses are unknown and obtaining early understanding of resulting pharmacokinetics is beneficial. This study applied a physiologically based pharmacokinetic modeling approach to predict the inhalation pharmacokinetics of caffeine and melatonin for different target indications related to the sleep-wake cycle. The model predicted rapid systemic delivery of caffeine and melatonin based on airway regional deposition of inhaled aerosol. A low inhaled dose of 1 mg of caffeine resulted in a 72.3-times lower plasma maximal concentration and was predicted to not improve cognitive performance task outcomes compared to oral consumption of coffee containing 80 mg of caffeine. Conversely, 2-mg oral and inhaled doses of melatonin under recommended directions of use result in more than 25.1- and 645-times higher plasma concentrations compared to endogenous melatonin, respectively. The recommended doses for inhalation products for potential improvement in the target indications vary widely. Additional research is needed to evaluate the human pharmacokinetics, efficacy, and safety of inhaled products. Given the lack of assessments, inhaled caffeine and melatonin must be consumed with caution as the toxicological concerns are not known and could outweigh the potential beneficial effects.

Associations of maternal sleep trajectories during pregnancy and adverse perinatal outcomes: a prospective cohort study

OBJECTIVE

Sleep problems are common in pregnant women and sleep is altered during pregnancy. However, the associations between sleep trajectory patterns and adverse maternal and neonatal outcomes are unclear. The current study aims to identify sleep trajectory patterns and explore their associations with adverse perinatal outcomes in a prospective cohort study.

METHODS

Pregnant women (N = 232) completed the Pittsburgh Sleep Quality Index each trimester during pregnancy in Tianjin, China. Perinatal outcomes were extracted from the hospital delivery records. Latent class growth analysis (LCGA) described the trajectories of sleep timing, duration, and efficiency. Multivariable linear regression and multivariable logistic regression were employed to evaluate associations between sleep trajectory patterns and perinatal outcomes.

RESULTS

Trajectories were identified for bedtime (early, 49.1%; delaying, 50.9%), wake-up time (early, 82.8% of the sample; late, 17.2%), duration (short, 5.2%; adequate 78.0%; excessive, 16.8%), and efficiency (high, 88.4%; decreasing, 11.6%). Compared with women in more optimal sleep groups, those in the late wake-up, excessive duration, and decreasing efficiency groups had babies with shorter birth lengths (β range, -0.50 to -0.28, p < 0.05). Moreover, women in the decreasing efficiency group had babies with lower birth weight (β, -0.44; p < 0.05). Women in the delaying bedtime group had greater odds of preterm delivery (OR, 4.57; p < 0.05), while those in the decreasing efficiency group had greater odds of cesarean section (OR, 3.12; p < 0.05).

CONCLUSIONS

Less optimal sleep trajectory patterns during pregnancy are associated with perinatal outcomes. Therefore, early assessment of maternal sleep during pregnancy is significant for identifying at-risk women and initiating interventions to reduce perinatal outcomes.

Melatonin inhibits tongue squamous cell carcinoma: Interplay of ER stress-induced apoptosis and autophagy with cell migration

Tongue squamous cell carcinoma (TSCC) occupies a high proportion of oral squamous cell carcinoma. TSCC features high lymph node metastasis rates and chemotherapy resistance with a poor prognosis. Therefore, an effective therapy strategy is needed to improve patient prognosis. Melatonin (MT) is a natural indole compound shown to have anti-tumor effects in several cancers. This study focused on the role and mechanism of MT in TSCC cells. The results of the study suggest that MT could inhibit cell proliferation in CRL-1623 cells. Western blot analysis showed the down-regulate of cyclin B1 and the up-regulate P21 protein by MT. MT was also shown to down-regulate the expression of Zeb1, Wnt5A/B, and β-catenin protein and up-regulate E-cadherin to inhibit the migration of CRL-1623 cells. MT also promoted the expression of ATF4, ATF6, Bip, BAP31 and CHOP in CRL-1623 cells leading to endoplasmic reticulum stress, and induced autophagy and apoptosis in CRL-1623 cells. Western blots showed that MT could promote the expression of Bax, LC3, and Beclin1 proteins and inhibit the expression of p62. We screened differentially expressed long non-coding RNAs (lncRNAs) in MT-treated cells and found that the expression of MALAT1 and H19 decreased. Moreover, MT inhibited tumor growth in nude mice inoculated with CRL-1623 cells. These results suggest that MT could induce autophagy, promote apoptosis, and provide a potential natural compound for the treatment of TSCC.

Evolutionary formation of melatonin and vitamin D in early life forms: insects take centre stage

Melatonin, a product of tryptophan metabolism via serotonin, is a molecule with an indole backbone that is widely produced by bacteria, unicellular eukaryotic organisms, plants, fungi and all animal taxa. Aside from its role in the regulation of circadian rhythms, it has diverse biological actions including regulation of cytoprotective responses and other functions crucial for survival across different species. The latter properties are also shared by its metabolites including kynuric products generated by reactive oxygen species or phototransfomation induced by ultraviolet radiation. Vitamins D and related photoproducts originate from phototransformation of ∆5,7 sterols, of which 7-dehydrocholesterol and ergosterol are examples. Their ∆5,7 bonds in the B ring absorb solar ultraviolet radiation [290-315 nm, ultraviolet B (UVB) radiation] resulting in B ring opening to produce previtamin D, also referred to as a secosteroid. Once formed, previtamin D can either undergo thermal-induced isomerization to vitamin D or absorb UVB radiation to be transformed into photoproducts including lumisterol and tachysterol. Vitamin D, as well as the previtamin D photoproducts lumisterol and tachysterol, are hydroxylated by cyochrome P450 (CYP) enzymes to produce biologically active hydroxyderivatives. The best known of these is 1,25-dihydroxyvitamin D (1,25(OH)2D) for which the major function in vertebrates is regulation of calcium and phosphorus metabolism. Herein we review data on melatonin production and metabolism and discuss their functions in insects. We discuss production of previtamin D and vitamin D, and their photoproducts in fungi, plants and insects, as well as mechanisms for their enzymatic activation and suggest possible biological functions for them in these groups of organisms. For the detection of these secosteroids and their precursors and photoderivatives, as well as melatonin metabolites, we focus on honey produced by bees and on body extracts of Drosophila melanogaster. Common biological functions for melatonin derivatives and secosteroids such as cytoprotective and photoprotective actions in insects are discussed. We provide hypotheses for the photoproduction of other secosteroids and of kynuric metabolites of melatonin, based on the known photobiology of ∆5,7 sterols and of the indole ring, respectively. We also offer possible mechanisms of actions for these unique molecules and summarise differences and similarities of melatoninergic and secosteroidogenic pathways in diverse organisms including insects.

Circadian disturbances by altering the light-dark cycle negatively affects hematopoietic function of bone marrow in mice

Circadian rhythms in metabolically active tissues are crucial for maintaining physical health. Circadian disturbance (CD) can cause various health issues, such as metabolic abnormalities and immune and cognitive dysfunctions. However, studies on the role of CD in immune cell development and differentiation, as well as the rhythmic expression of the core clock genes and their altered expression under CD, remain unclear. Therefore, we exposed C57bl/6j mice to repeated reversed light-dark cycles for 90 days to research the effects of CD on bone marrow (BM) hematopoietic function. We also researched the effects of CD on endogenous circadian rhythms, temporally dependent expression in peripheral blood and myeloid leukocytes, environmental homeostasis within BM, and circadian oscillations of hematopoietic-extrinsic cues. Our results confirmed that when the light and dark cycles around mice were frequently reversed, the circadian rhythmic expression of the two main circadian rhythm markers, the hypothalamic clock gene, and serum melatonin, was disturbed, indicating that the body was in a state of endogenous CD. Furthermore, CD altered the temporally dependent expression of peripheral blood and BM leukocytes and destroyed environmental homeostasis within the BM as well as circadian oscillations of hematopoietic-extrinsic cues, which may negatively affect BM hematopoiesis in mice. Collectively, these results demonstrate that circadian rhythms are vital for maintaining health and suggest that the association between CD and hematopoietic dysfunction warrants further investigation.

Understanding zebrafish sleep and wakefulness physiology as an experimental model for biomedical research

Sleep is a globally observable fact, or period of reversible distracted rest, that can be distinguished from arousal by various behavioral criteria. Although the function of sleep is an evolutionarily conserved behavior, its mechanism is not yet clear. The zebrafish (Danio rerio) has become a valuable model for neurobehavioral studies such as studying learning, memory, anxiety, and depression. It is characterized by a sleep-like state and circadian rhythm, making it comparable to mammals. Zebrafish are a good model for behavioral studies because they share genetic similarities with humans. A number of neurotransmitters are involved in sleep and wakefulness. There is a binding between melatonin and the hypocretin system present in zebrafish. The full understanding of sleep and wakefulness physiology in zebrafish is still unclear among researchers. Therefore, to make a clear understanding of the sleep/wake cycle in zebrafish, this article covers the mechanism involved behind it, and the role of the neuromodulator system followed by the mechanism of the HPA axis.

The association between artificial light at night and gestational diabetes mellitus: A prospective cohort study from China

BACKGROUND

Emerging evidence suggests that exposure to outdoor artificial light at night (ALAN) may be associated with diabetes. However, limited research explores the relationship between outdoor ALAN and gestational diabetes mellitus (GDM).

METHODS

We utilized data from a multilevel infant and early life cohort study conducted in Sichuan Province, China, between February 2018 and April 2021. A total of 9,120 participants were included in the final analysis. Outdoor ALAN exposure at participants' residential locations was estimated using time-varying satellite data, focusing on persistent night-time illumination at a scale of approximately 500x500m. The information about GDM was obtained from medical records. After adjusting for potential confounders, multivariable logistic regression models and restricted cubic splines were employed to estimate the association between ALAN exposure during pregnancy and GDM.

RESULTS

Among the total recruitments, 1,484 (16.27%) women were diagnosed with GDM. Compared to women without GDM, those with GDM had a significantly higher mean outdoor ALAN exposure during pregnancy (18.98 nW/cm2/sr1 vs 24.28 nW/cm2/sr1, P < 0.001). Results from multivariable logistic models showed that higher outdoor ALAN exposure during pregnancy could increase the risk of GDM (OR (95% CI) 1st+2nd trimesters ALAN = 1.253 (1.157-1.356)). Meanwhile, results from the restricted cubic spline further indicated a non-linear association between outdoor ALAN exposure during pregnancy and GDM. Generally, with the radiance of the first two trimesters of ALAN increasing to about 17.9 nW/cm2/sr1, outdoor ALAN exposure became a risk factor for GDM. However, when the radiance of ALAN reached about 40.7 nW/cm2/sr1, the continued increasing OR estimation (OR (95% CI) = 1.489 (1.223-1.814)) of outdoor ALAN changed to steady.

CONCLUSION

Our findings suggested that high levels of outdoor ALAN exposure during pregnancy can be associated with an increased risk of GDM, and a non-linear relationship pattern might exist. These findings substantially augment existing evidence, positing outdoor ALAN as an emergent, modifiable risk factor for GDM.

Sirtuins in intervertebral disc degeneration: current understanding

BACKGROUND

Intervertebral disc degeneration (IVDD) is one of the etiologic factors of degenerative spinal diseases, which can lead to a variety of pathological spinal conditions such as disc herniation, spinal stenosis, and scoliosis. IVDD is a leading cause of lower back pain, the prevalence of which increases with age. Recently, Sirtuins/SIRTs and their related activators have received attention for their activity in the treatment of IVDD. In this paper, a comprehensive systematic review of the literature on the role of SIRTs and their activators on IVDD in recent years is presented. The molecular pathways involved in the regulation of IVDD by SIRTs are summarized, and the effects of SIRTs on senescence, inflammatory responses, oxidative stress, and mitochondrial dysfunction in myeloid cells are discussed with a view to suggesting possible solutions for the current treatment of IVDD.

PURPOSE

This paper focuses on the molecular mechanisms by which SIRTs and their activators act on IVDD.

METHODS

A literature search was conducted in Pubmed and Web of Science databases over a 13-year period from 2011 to 2024 for the terms "SIRT", "Sirtuin", "IVDD", "IDD", "IVD", "NP", "Intervertebral disc degeneration", "Intervertebral disc" and "Nucleus pulposus".

RESULTS

According to the results, SIRTs and a large number of activators showed positive effects against IVDD.SIRTs modulate autophagy, myeloid apoptosis, oxidative stress and extracellular matrix degradation. In addition, they attenuate inflammatory factor-induced disc damage and maintain homeostasis during disc degeneration. Several clinical studies have reported the protective effects of some SIRTs activators (e.g., resveratrol, melatonin, honokiol, and 1,4-dihydropyridine) against IVDD.

CONCLUSION

The fact that SIRTs and their activators play a hundred different roles in IVDD helps to better understand their potential to develop further treatments for IVDD.

NOVELTY

This review summarizes current information on the mechanisms of action of SIRTs in IVDD and the challenges and limitations of translating their basic research into therapy.

Association of sugar-sweetened beverage consumption and sleep quality with anxiety symptoms: a cross-sectional study of Tibetan college students at high altitude

Background

Research on the association between sugar-sweetened beverages (SSBs) consumption and sleep quality with anxiety symptoms has been highly emphasized. However, past studies have focused on college students in plains areas, while fewer research studies have been conducted on Tibetan college students at high altitudes. Whether this association changes due to ethnicity or altitude is unclear. The present study will contribute to the prevention and intervention of depressive symptoms among Tibetan college students at high altitude.

Methods

A self-assessment questionnaire was administered to 3,026 university students (1,491 boys students, 49.27%) on SSBs consumption, sleep quality and anxiety symptoms status in the Tibetan Plateau, a high-altitude region of China. Logistic regression analysis and ordered logistic regression analysis in generalized linear model were used to analyze the association between SSBs consumption and sleep quality with anxiety symptoms.

Results

The prevalence of anxiety symptoms among Tibetan college students at high altitude was 26.9%. SSBs consumption of ≤1 times/week, 2-5 times/week, and ≥ 6 times/week were 20.7, 28.1, and 45.7%, respectively, with statistically significant differences (χ2 value of 134.353, p < 0.001). Anxiety detection rates for Sleep quality of Good (PSQI ≤5), Moderate (PSQI 6-7), and Poor (PSQI >7) were 16.8, 19.8, and 32.0%, respectively, and the difference was also statistically significant (χ2 value was 73.761, p < 0.001). The ordered logistic regression analysis in the generalized linear model showed that, overall, the group of college students with SSBs ≤1 times/week and sleep quality of Good served as the reference group, and the group with SSBs ≥6 times/week and sleep quality of Poor (OR: 5.06, 95% CI: 3.75-6.83) had the highest risk of anxiety symptoms.

Conclusion

SSBs consumption and sleep quality were associated with anxiety symptoms, and there was an interaction effect. Effective control of SSBs consumption and improvement of sleep quality may be important factors in preventing and reducing the occurrence of anxiety symptoms.

Ferroptosis and oxidative stress in endometriosis: A systematic review of the literature

BACKGROUND

Endometriosis (EMT) a common gynecological condition in women, an inflammatory disease characterized by the presence of endometrial tissue on organs and tissues in the pelvis, and is mainly associated with chronic pelvic pain and infertility. As the etiology has not been fully elucidated, current treatment is limited to surgery, hormones and painkillers, with more side effects and difficulty in achieving long-term relief. Oxidative stress manifests itself as an overproduction of reactive oxygen species, which has an integral impact in the pathology of female reproductive disorders. In this review, we evaluate the mechanisms of iron overload-induced oxidative stress and ferroptosis in EMT and their pathophysiological implications.

METHODS

Because the etiology has not been fully elucidated, current treatments are limited to surgery, hormones, and painkillers, which have many side effects and are difficult to achieve long-term relief.

RESULTS

We interpreted that antioxidants as well as ferroptosis inducers show promising results in the treatment of EMT, but their application in this population needs to be further investigated.

CONCLUSION

In combination with the interpretation of previous studies, it was shown that iron overload is present in the peritoneal fluid, endometriotic lesions, peritoneum and macrophages in the abdominal cavity. However, the programmed cellular ferroptosis associated with iron overload is resisted by endometriotic foci, which is critical to the pathophysiology of EMT with local iron overload and inflammation.

The impact of physiological variations on personalized reference intervals and decision limits: an in-depth analysis

The interpretation of laboratory data is a comparative procedure. Physicians typically need reference values to compare patients' laboratory data for clinical decisions. Therefore, establishing reliable reference data is essential for accurate diagnosis and patient monitoring. Human metabolism is a dynamic process. Various types of systematic and random fluctuations in the concentration/activity of biomolecules are observed in response to internal and external factors. In the human body, several biomolecules are under the influence of physiological rhythms and are therefore subject to ultradian, circadian and infradian fluctuations. In addition, most biomolecules are also characterized by random biological variations, which are referred to as biological fluctuations between subjects and within subjects/individuals. In routine practice, reference intervals based on population data are used, which by nature are not designed to capture physiological rhythms and random biological variations. To ensure safe and appropriate interpretation of patient laboratory data, reference intervals should be personalized and estimated using individual data in accordance with systematic and random variations. In this opinion paper, we outline (i) the main variations that contribute to the generation of personalized reference intervals (prRIs), (ii) the theoretical background of prRIs and (iii) propose new methods on how to harmonize prRIs with the systematic and random variations observed in metabolic activity, based on individuals' demography.

Stress begets stress: The moderating role of childhood adversity in the relationship between job stress and sleep quality among nurses

BACKGROUND

Nurses exhibit considerable variations in sleep quality and experience high job stress levels. Distal factors, such as childhood adversity, and proximal factors, both influence sleep quality. We investigated the moderating role of childhood adversity with job stress and sleep quality, and whether this aligns with the stress-sensitization or stress-amplification models.

METHODS

The impact of job stressors' total score and its dimensions on sleep quality was analyzed using traditional linear regression models and the extreme gradient boosting machine learning algorithm. The hierarchical regression examined the moderating role of childhood adversity in the relationship between job stress and sleep quality. An interactive tool was used to visualize the results.

RESULTS

Among the dimensions of job stress, "time allocation and workload" strongly correlated with sleep quality, followed by "nursing profession and work problems," "patient care issues," "management and interpersonal problems," and "working environment and equipment problems." The moderating role of childhood adversity in the relationship between different dimensions of job stressors (except working environment and equipment problems) and sleep quality aligns with the stress-sensitization model.

LIMITATIONS

This study was susceptible to recall bias and objective sleep data were unavailable. Cross-sectional study design was used, thus limiting causal inferences. Finally, the moderating effect of childhood adversity on subsequent stress among nurses remains unclear.

CONCLUSION

Childhood adversity and job stress were integrated into a stress-sensitization model, providing a nuanced and specific examination of sleep quality. Healthcare policymakers should focus on job stress and childhood adversity, improve nurses' sleep quality, and ultimately benefit patient care and outcomes.

Effect of hospital elder life program on the incidence of delirium: A systematic review and meta-analysis of clinical trials

OBJECTIVE

This meta-analysis aims to investigate the effect of the Hospital Elder Life Program (HELP) on the incidence of delirium, delirium scores, length of hospital stay, and incidence of falls.

METHODS

Four databases (PubMed, Embase, Cochrane Library, and Web of Science) were searched from inception until January 18, 2024. The search specifically targeted randomized controlled trials (RCTs). Two independent researchers conducted literature screening, quality assessment, and data extraction. The meta-analysis was performed using Review Manager 5.4.1 and Stata 15.1 software.

RESULTS

The final analysis included a total of 9 RCTs with 2583 patients. The findings from the meta-analysis indicated that HELP was found to considerably reduce the incidence of delirium and the length of hospital stay when compared to the control group. Nevertheless, no statistically significant differences were observed between the two groups in terms of delirium scores and fall rates.

CONCLUSION

In this meta-analysis, HELP can effectively reduce the incidence of delirium and lead to a shorter hospital stay.

Melatonin regulates the circadian rhythm to ameliorate postoperative sleep disorder and neurobehavioral abnormalities in aged mice

BACKGROUND

Postoperative sleep disorder (PSD) and delirium, which may be associated with surgery and inhalational anesthetics, induce adverse effects in old adults. Emerging evidence indicates that circadian rhythm contributes to various neuropathological diseases, including Alzheimer's disease. Thus, we analyzed the potential role of circadian rhythm in PSD and delirium-like behavior in aged mice and determined whether exogenous melatonin could facilitate entrainment of the circadian rhythm after laparotomy under sevoflurane anesthesia.

METHODS

We selected old C57BL/6J mice which receiving laparotomy/sevoflurane anesthesia as model animals. We employed buried food, open field, and Y maze test to assess delirium-like behavior, and electroencephalography/electromyography (EEG/EMG) were used to investigate sleep changes. We analyzed the transcription rhythm of clock genes in superchiasmatic nucleus (SCN) to explore the effects of surgery and melatonin pretreatment on the circadian rhythm. Then, we measured melatonin receptor levels in SCN and ERK/CREB pathway-related proteins in hippocampus and prefrontal cortex to assess their role in PSDs and delirium-like behavior.

RESULTS

Laparotomy under sevoflurane anesthesia had a greater influence than sevoflurane alone, leading to sleep disorder, a shift in sleep-wake rhythm, and delirium-like behavior. Bmal1, Clock, and Cry1 mRNA expression showed a peak shift, MT1 melatonin receptor expression level was increased in the SCN, and p-ERK/ERK and p-CREB/CREB were decreased in hippocampus and prefrontal cortex of aged mice 1 day after laparotomy. Melatonin showed significant efficacy in ameliorating PSD and delirium-like behavior and restoring the circadian rhythm, reversing melatonin receptor and ERK/CREB pathway expression abnormalities. In addition, most of the beneficial effect of melatonin was antagonized by luzindole, a melatonin receptor antagonist.

CONCLUSIONS

Melatonin receptors in SCN, circadian rhythm, and ERK/CREB signaling pathway participate in the pathophysiological processes of PSD and delirium-like behavior. Melatonin intervention could be a potential preventative approach for PSD and delirium.

Photoperiod and metabolic health: evidence, mechanism, and implications

Circadian rhythms are evolutionarily programmed biological rhythms that are primarily entrained by the light cycle. Disruption of circadian rhythms is an important risk factor for several metabolic disorders. Photoperiod is defined as total duration of light exposure in a day. With the extended use of indoor/outdoor light, smartphones, television, computers, and social jetlag people are exposed to excessive artificial light at night increasing their photoperiod. Importantly long photoperiod is not limited to any geographical region, season, age, or socioeconomic group, it is pervasive. Long photoperiod is an established disrupter of the circadian rhythm and can induce a range of chronic health conditions including adiposity, altered hormonal signaling and metabolism, premature ageing, and poor psychological health. This review discusses the impact of exposure to long photoperiod on circadian rhythms, metabolic and mental health, hormonal signaling, and ageing and provides a perspective on possible preventive and therapeutic approaches for this pervasive challenge.

Therapeutic applications of melatonin in disorders related to the gastrointestinal tract and control of appetite

Most animals have large amounts of the special substance melatonin, which is controlled by the light/dark cycle in the suprachiasmatic nucleus. According to what is now understood, the gastrointestinal tract (GIT) and other areas of the body are sites of melatonin production. According to recent studies, the GIT and adjacent organs depend critically on a massive amount of melatonin. Not unexpectedly, melatonin's many biological properties, such as its antioxidant, anti-inflammatory, pro-apoptotic, anti-proliferative, anti-metastasis, and antiangiogenic properties, have drawn the attention of researchers more and more. Because melatonin is an antioxidant, it produces a lot of secretions in the GIT's mucus and saliva, which shields cells from damage and promotes the development of certain GIT-related disorders. Melatonin's ability to alter cellular behavior in the GIT and other associated organs, such as the liver and pancreas, is another way that it functions. This behavior alters the secretory and metabolic activities of these cells. In this review, we attempted to shed fresh light on the many roles that melatonin plays in the various regions of the gastrointestinal tract by focusing on its activities for the first time.

Nocturnal Melatonin Ingestion Improves Soccer Players' Short-Term Maximal Performances on the Following Day

Purpose: Exogenous melatonin has been proven to have beneficial effects on sleep. A good sleep quality promotes recovery and improves physical performance. In this sense, the present study aimed to explore the potential effect of nocturnal melatonin ingestion on psycho-cognitive and short-term maximal performances, in the following morning. Method: Twelve professional soccer players (22.9 ± 1.3 years, 1.80 ± 0.05 m, and 72.0 ± 8.8 kg) volunteered to perform two separate testing sessions after either nocturnal melatonin or placebo ingestion. The next morning, participants performed the following psycho-cognitive and physical tests: Hooper's index, reaction time, vigilance, handgrip strength (HG), squat jump (SJ), modified agility T-test (MAT) and Wingate anaerobic test (WanT). Rating of perceived exertion (RPE) and blood lactate [La] were recorded, respectively, immediately and 3 min after the WanT. Blood glucose [GL] was measured before and 3 min after WanT. Results: Compared with placebo, melatonin improved subjective sleep quality, short-term maximal performances (HG and SJ), reaction-time, as well as peak and mean WanT powers and decreased fatigue index and RPE scores. However, [La] and [GL] were not affected by melatonin ingestion. Conclusion: Nocturnal melatonin intake before sleep has beneficial effects on cognitive and physical performances the following day.

Receptor-Mediated and Receptor-Independent Actions of Melatonin in Vertebrates

Melatonin (N-acetyl-5-methoxytryptamine) is an indolamine that is synthesized from tryptophan in the pineal glands of vertebrates through four enzymatic reactions. Melatonin is a quite unique bioactive substance, characterized by a combination of both receptor-mediated and receptor-independent actions, which promote the diverse effects of melatonin. One of the main functions of melatonin, via its membrane receptors, is to regulate the circadian or seasonal rhythm. In mammals, light information, which controls melatonin synthesis, is received in the eye, and transmitted to the pineal gland, via the suprachiasmatic nucleus, where the central clock is located. Alternatively, in many vertebrates other than mammals, the pineal gland cells, which are involved in melatonin synthesis and secretion and in the circadian clock, directly receive light. Recently, it has been reported that melatonin possesses several metabolic functions, which involve bone and glucose, in addition to regulating the circadian rhythm. Melatonin improves bone strength by inhibiting osteoclast activity. It is also known to maintain brain activity during sleep by increasing glucose uptake at night, in an insulin-independent manner. Moreover, as a non-receptor-mediated action, melatonin has antioxidant properties. Melatonin has been proven to be a potent free radical scavenger and a broad-spectrum antioxidant, even protecting organisms against radiation from space. Melatonin is a ubiquitously distributed molecule and is found in bacteria, unicellular organisms, fungi, and plants. It is hypothesized that melatonin initially functioned as an antioxidant, then, in vertebrates, it combined this role with the ability to regulate rhythm and metabolism, via its receptors.

Melatonin in cancer biology: pathways, derivatives, and the promise of targeted delivery

Melatonin, historically recognized for its primary role in regulating circadian rhythms, has expanded its influence particularly due to its wide range of biological activities. It has firmly established itself in cancer research. To highlight its versatility, we delved into how melatonin interacts with key signaling pathways, such as the Wnt/β-Catenin, PI3K, and NF-κB pathways, which play foundational roles in tumor development and progression. Notably, melatonin can intricately modulate these pathways, potentially affecting various cellular functions such as apoptosis, metastasis, and immunity. Additionally, a comprehensive review of current clinical studies provides a dual perspective. These studies confirm melatonin's potential in cancer management but also underscore its inherent limitations, particularly its limited bioavailability, which often relegates it to a supplementary role in treatments. Despite this limitation, there is an ongoing quest for innovative solutions and current advancements include the development of melatonin derivatives and cutting-edge delivery systems. By synthesizing the past, present, and future, this review provides a detailed overview of melatonin's evolving role in oncology, positioning it as a potential cornerstone in future cancer therapeutics.

Bridging neurotrophic factors and bioactive peptides to Alzheimer's disease

Alzheimer's disease (AD) is a neurodegenerative disorder. As the demographic shifting towards an aging population, AD has emerged as a prominent public health concern. The pathogenesis of AD is complex, and there are no effective treatment methods for AD until now. In recent years, neurotrophic factors and bioactive peptides including brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF), irisin, melatonin, have been discovered to exert neuroprotective functions for AD. Bioactive peptides can be divided into two categories based on their sources: endogenous and exogenous. This review briefly elaborates on the pathogenesis of AD and analyzes the regulatory effects of endogenous and exogenous peptides on the pathogenesis of AD, thereby providing new therapeutic targets for AD and a theoretical basis for the application of bioactive peptides as adjunctive therapies for AD.

Sleep and allergic diseases among young Chinese adults from the Singapore/Malaysia Cross-Sectional Genetic Epidemiology Study (SMCGES) cohort

BACKGROUND AND OBJECTIVE

Sleep disruption has been shown to affect immune function and thus influence allergic disease manifestation. The specific effects of sleep on allergic diseases, however, are less well-established; hence, in a unique population of young Chinese adults, we investigated the association between sleep and allergic disease.

METHODS

Young Chinese adults recruited from Singapore in the Singapore/Malaysia Cross-Sectional Genetic Epidemiology Study (SMCGES) were analyzed. We used the International Study of Asthma and Allergies in Childhood (ISAAC) protocol and a skin prick test to determine atopic dermatitis (AD), allergic rhinitis (AR), and asthma status. Information regarding total sleep time (TST) and sleep quality (SQ) was also obtained.

RESULTS

Of 1558 participants with a mean age of 25.0 years (SD = 7.6), 61.4% were female, and the mean total sleep time (TST) was 6.8 h (SD = 1.1). The proportions of AD, AR, and asthma were 24.5% (393/1542), 36.4% (987/1551), and 14.7% (227/1547), respectively. 59.8% (235/393) of AD cases suffered from AD-related sleep disturbances, 37.1% (209/564) of AR cases suffered from AR-related sleep disturbances, and 25.1% (57/227) of asthma cases suffered from asthma-related sleep disturbances. Only asthma cases showed a significantly lower mean TST than those without asthma (p = 0.015). Longer TST was significantly associated with lower odds of AR (OR = 0.905, 95% CI = 0.820-0.999) and asthma (OR = 0.852, 95% CI = 0.746-0.972). Linear regression analyses showed that lower TST was significantly associated with asthma (β =  - 0.18, SE = 0.076, p-value = 0.017), and AR when adjusted for AR-related sleep disturbances (β =  - 0.157, SE = 0.065, p-value = 0.016). Only sleep disturbances due to AR were significantly associated with a poorer SQ (OR = 1.962, 95% CI = 1.245-3.089).

CONCLUSIONS

We found that sleep quality, but not sleep duration was significantly poorer among AD cases, although the exact direction of influence could not be determined. In consideration of the literature coupled with our findings, we posit that TST influences allergic rhinitis rather than vice versa. Finally, the association between TST and asthma is likely mediated by asthma-related sleep disturbances, since mean TST was significantly lower among those with nighttime asthma symptoms. Future studies could consider using objective sleep measurements coupled with differential expression analysis to investigate the pathophysiology of sleep and allergic diseases.

Significance of Melatonin in the Regulation of Circadian Rhythms and Disease Management

Melatonin, the 'hormone of darkness' is a neuronal hormone secreted by the pineal gland and other extra pineal sites. Responsible for the circadian rhythm and seasonal behaviour of vertebrates and mammals, melatonin is responsible for regulating various physiological conditions and the maintenance of sleep, body weight and the neuronal activities of the ocular sites. With its unique amphiphilic structure, melatonin can cross the cellular barriers and elucidate its activities in the subcellular components, including mitochondria. Melatonin is a potential scavenger of oxygen and nitrogen-reactive species and can directly obliterate the ROS and RNS by a receptor-independent mechanism. It can also regulate the pro- and anti-inflammatory cytokines in various pathological conditions and exhibit therapeutic activities against neurodegenerative, psychiatric disorders and cancer. Melatonin is also found to show its effects on major organs, particularly the brain, liver and heart, and also imparts a role in the modulation of the immune system. Thus, melatonin is a multifaceted candidate with immense therapeutic potential and is still considered an effective supplement on various therapies. This is primarily due to rectification of aberrant circadian rhythm by improvement of sleep quality associated with risk development of neurodegenerative, cognitive, cardiovascular and other metabolic disorders, thereby enhancing the quality of life.

Melatonin inhibits fibroblast cell functions and hypertrophic scar formation by enhancing autophagy through the MT2 receptor-inhibited PI3K/Akt /mTOR signaling

Hypertrophic scar (HS) is a fibrotic skin condition and characterized by abnormal proliferation of myofibroblasts and accumulation of extracellular matrix. Melatonin, an endogenous hormone, can alleviate fibrosis in multiple models of diseases. This study examined the effect of melatonin on fibrosis in primary fibroblasts from human HS (HSFs) and a rabbit ear model and potential mechanisms. Melatonin treatment significantly decreased the migration and contraction capacity, collagen and α-smooth muscle actin (α-SMA) production in HSFs. RNA-sequencing and bioinformatic analyses indicated that melatonin modulated the expression of genes involved in autophagy and oxidative stress. Mechanistically, melatonin treatment attenuated the AKT/mTOR activation through affecting the binding of MT2 receptor with PI3K to enhance autophagy, decreasing fibrogenic factor production in HSFs. Moreover, melatonin treatment inhibited HS formation in rabbit ears by enhancing autophagy. The anti-fibrotic effects of melatonin were abrogated by treatment with an autophagy inhibitor (3-methyladenine, 3-MA), an Akt activator (SC79), or an MT2 selective antagonist (4-phenyl-2propionamidotetralin, 4-P-PDOT). Therefore, melatonin may be a potential drug for prevention and treatment of HS.

Melatonin Exerts an Anti-Panoptoic Role in Spinal Cord Ischemia-Reperfusion Injured Rats

Paraplegia is a serious consequence of spinal cord ischemia-reperfusion (SCIR) injury, which leads to neuron death and permanent loss of motor function. However, there is no effective treatment for SCIR. Melatonin exerts a neuroprotective effect in neurodegenerative diseases. However, whether pyroptosis, apoptosis, and necroptosis (PANoptosis) is the primary cause of the massive neural death in SCIR is unknown, and if melatonin exhibits anti-PANoptotic effect in rescuing the disastrous damage is to be decided. This study indicates that melatonin confers neuroprotection in SCIR, attenuating the loss of Nissl body and improving Basso, Beattie & Bresnahan locomotor rating scale scores. Specifically, the apoptotic hallmarks in neurons are increased in SCIR injured spinal cord compared to the sham group. The upregulated trend is reversed by melatonin while the effect of melatonin is abolished by the administration of luzindole, a selective melatonin receptor antagonist. Moreover, similar patterns are found in the necroptotic markers in neurons, the pyroptotic indicators, and the interleukin-1β staining in microglia. In conclusion, PANoptosis may underlie the mass neural death and paraplegia in SCIR, and melatonin confers neuroprotection to the spinal cord via inhibiting PANoptosis.

Associations between food insecurity and Sleep Duration, Quality, and Disturbance among older adults from six low- and middle-income countries

OBJECTIVES

Although food insecurity has been associated with poor sleep outcomes in young and middle-aged adults, few studies have examined this relationship in older adults. This study aimed to examine the relationship between food insecurity and sleep duration, quality, and disturbance among older adults in six low-income countries (LMICs).

DESIGN AND SETTING

We analyzed nationally representative cross-sectional data from 33,460 adults (≥50 years) from the Study on global AGEing and adult health (SAGE).

MEASUREMENTS

Food insecurity (FI) was assessed using two questions regarding the frequency of eating less and hunger caused by a lack of food. Sleep outcomes included self-reported sleep duration, sleep quality, and sleep disturbances (difficulty falling asleep, frequent sleep interruptions, and early awakening) assessed based on self-reports over two nights. Multivariable logistic regression was used to assess country-specific relationships between food insecurity and sleep outcomes, and random-effects models were used to estimate pooled associations.

RESULTS

The prevalence of FI among older adults in the overall population was 16.2%. In pooled analyses, FI was significantly associated with long sleep duration ≥ 9 h (OR=1.58, 95% CI: 1.30 to 1.93; P=0.001). There were also significant pooled associations between FI and poor sleep quality (OR=1.34, 95% CI: 1.14 to 1.56; P < 0.001) and sleep disturbances (OR=1.44, 95% CI: 1.08 to 1.91; P = 0.014).

CONCLUSIONS

In conclusion, the current study found that FI is adversely associated with sleep duration, quality and disturbances in older adults, with some heterogeneity by country. The findings suggest food policies and intervention programs are needed for vulnerable households.

Heatwave exposure in relation to decreased sleep duration in older adults

Few studies have delved into the effects of heatwaves on sleep duration loss among older adults. Our study examined correlations between heatwave exposure and sleep duration reductions in this demographic. Utilizing data of 7,240 older adults drawn from the China Health and Retirement Longitudinal Study (CHARLS) from 2015 to 2018, we assessed sleep duration differences between the baseline year (2015) and follow-up year (2018). Absolute reductions in sleep duration were defined as differences of ≥ 1, 1.5, or 2 h. Changes in sleep duration were categorized based on cut-offs of 5 and 8 h, including excessive decrease, moderate to short and persistent short sleep duration types. 12 heatwave definitions combining four thresholds (90th, 92.5th, 95th, and 97.5th percentiles of daily minimum temperature) and three durations (≥2, ≥3 and ≥ 4 days) were used. Heatwave exposure was determined by the difference in the number of 12 preceding months' heatwave days or events in 2015 and the number of 12 preceding months' heatwave days or events in 2018. The results showed that increased heatwave events (defined as ≥ P90th percentile & lasting three days) were associated with a higher likelihood of ≥ 1-hour sleep reduction and persistent short sleep duration. An increase in heatwave event (defined as ≥ P95th percentile & lasting three days) was linked to shifts from moderate to short sleep duration. For the association between an absolute reduction in sleep duration and heatwave exposure, while higher thresholds signified greater sleep reduction risks, the effect estimates of longer durations were not uniformly consistent. We observed that air pollution and green space modified the relationship between heatwaves and sleep duration. Females, urban residents, and individuals with chronic diseases were identified as vulnerable populations. This study found that increased heatwave exposure was associated with a higher risk of sleep duration loss in older adults.

Effect of oral melatonin treatment on insulin resistance and diurnal blood pressure variability in night shift workers. A double-blind, randomized, placebo-controlled study

BACKGROUND

Night shift work is associated with sleep disturbances, obesity, and cardiometabolic diseases. Disruption of the circadian clock system has been suggested to be an independent cause of type 2 diabetes and cardiovascular disease in shift workers. We aimed to improve alignment of circadian timing with social and environmental factors with administration of melatonin.

METHODS

In a randomized, placebo-controlled, prospective study, we analysed the effects of 2 mg of sustained-release melatonin versus placebo on glucose tolerance, insulin resistance indices, sleep quality, circadian profiles of plasma melatonin and cortisol, and diurnal blood pressure profiles in 24 rotating night shift workers during 12 weeks of treatment, followed by 12 weeks of wash-out. In a novel design, the time of melatonin administration (at night or in the morning) depended upon the shift schedule. We also compared the baseline profiles of the night shift (NS) workers with 12 healthy non-night shift (NNS)-working controls.

RESULTS

We found significantly impaired indices of insulin resistance at baseline in NS versus NNS (p < 0.05), but no differences in oral glucose tolerance tests nor in the diurnal profiles of melatonin, cortisol, or blood pressure. Twelve weeks of melatonin treatment did not significantly improve insulin resistance, nor did it significantly affect diurnal blood pressure or melatonin and cortisol profiles. Melatonin administration, however, caused a significant improvement in sleep quality which was significantly impaired in NS versus NNS at baseline (p < 0.001).

CONCLUSIONS

Rotating night shift work causes mild-to-moderate impairment of sleep quality and insulin resistance. Melatonin treatment at bedtime improves sleep quality, but does not significantly affect insulin resistance in rotating night shift workers after 12 weeks of administration.

[Melatonin for the regulation of sleep and other biological rhythms]

Melatonin, as the hormone of the circadian system, plays a major role in regulating physiological functions and facilitating adaptation to environmental changes. Here we provide brief overview of circadian physiology, as related to the use of melatonin as hormone replacement therapy for older individuals with reduced melatonin secretion and melatonin treatment for patients with chronic insomnia or circadian desynchronization. Emphasizing the importance of minimal effective doses, we discuss the use of both immediate and delayed-release formulations, stress the significance of regular administration timing, and advise against exposure to bright light during increase in melatonin levels. Our discussion underscores that the medical guidance is essential for utilizing melatonin-containing preparations in the therapy of chronic insomnia.

Melatonin and Related Compounds as Antioxidants

Oxidative stress has been reported to be involved in the onset and development of several diseases, including neurodegenerative and cardiovascular disorders, some types of cancer, and diabetes. Therefore, finding strategies to detoxify free radicals is an active area of research. One of these strategies is the use of natural or synthetic antioxidants. In this context, melatonin (MLT) has been proven to possess most of the required characteristics of an efficient antioxidant. In addition, its protection against oxidative stress continues after being metabolized, since its metabolites also exhibit antioxidant capacity. Based on the appealing properties of MLT and its metabolites, various synthetic analogues have been developed to obtain compounds with higher activity and lower side effects. This review addresses recent studies with MLT and related compounds as potential antioxidants.

Assessment and Management of Sleep Disturbances in Atopic Dermatitis: A Review

Atopic dermatitis (AD) is a chronic burdensome inflammatory skin disease with well-established cutaneous and systemic comorbidities and disease burden. AD particularly has profound impacts on sleep in individuals of all ages. Sleep disturbances (SDs) affect 6.2% of school-age children and 33-87.1% of adults with AD. This narrative review addresses the burden of SD in AD patients, as well as biological mechanisms of SD in AD, including biological clocks influencing sleep, inflammation, and behavior. Approaches for early detection, diagnosis, objective quantification, patient education, and management are reviewed. It is imperative to break the itch-scratch cycle to reduce SDs and improve quality of life in individuals with AD.

Melatonin and its Emerging Physiological Role in Reproduction: A Review and Update

Melatonin is a neuroendocrine hormone secreted by the pineal gland. The secretion of melatonin follows a circadian rhythm controlled by the suprachiasmatic nucleus, and its secretion is synchronized with the changes in light and dark periods in nature, with the highest secretion level at night. Melatonin is a critical hormone that coordinates external light stimulation and cellular responses of the body. It transmits information about the environmental light cycle, including the circadian and seasonal rhythms, to the relevant tissues and organs in the body, which, along with changes in its secretion level, ensures that its regulated functional activities are adapted in response to changes in the outside environment. Melatonin takes beneficial actions mainly through the interaction with specific membrane-bound receptors, termed MT1 and MT2. Melatonin also acts as a scavenger of free radicals via non-receptor-mediated mechanism. For more than half of acentury melatonin has been associated with vertebrate reproduction, especially in the context of seasonal breeding. Though modern humans show little remaining reproductive seasonality, the relationships between melatonin and human reproduction continue to attract extensive attention. Melatonin plays important roles in improving mitochondrial function, reducing the damage of free radicals, inducing oocyte maturation, increasing fertilization rate and promoting embryonic development, which improves the outcomes of in vitro fertilization and embryo transfer. The present article reviews the progress that has been made in our evolving understanding of the physiological role of melatonin in reproduction and its potential clinical applications in reproductive medicine.

Melatonin as a Mediator of the Gut Microbiota-Host Interaction: Implications for Health and Disease

In recent years, the role played by melatonin on the gut microbiota has gained increasingly greater attention. Additionally, the gut microbiota has been proposed as an alternative source of melatonin, suggesting that this antioxidant indoleamine could act as a sort of messenger between the gut microbiota and the host. This review analyses the available scientific literature about possible mechanisms involved in this mediating role, highlighting its antioxidant effects and influence on this interaction. In addition, we also review the available knowledge on the effects of melatonin on gut microbiota composition, as well as its ability to alleviate dysbiosis related to sleep deprivation or chronodisruptive conditions. The melatonin-gut microbiota relationship has also been discussed in terms of its role in the development of different disorders, from inflammatory or metabolic disorders to psychiatric and neurological conditions, also considering oxidative stress and the reactive oxygen species-scavenging properties of melatonin as the main factors mediating this relationship.

Berry Consumption and Sleep in the Adult US General Population: Results from the National Health and Nutrition Examination Survey 2005-2018

INTRODUCTION

Poor sleep is associated with numerous adverse health outcomes. Berries are rich in micronutrients and antioxidants that may improve sleep quality and duration. We determined the association of berry consumption and sleep duration and sleep difficulty among adult participants in NHANES.

METHODS

We analyzed the diet of US adults aged ≥ 20 y using two non-consecutive 24 h recalls from the National Health and Nutrition Examination Survey 2005 to 2018 (N = 29,217). Poor sleep quality was measured by sleep duration (short sleep duration: <7 h), long sleep (≥9 h), and reported sleep difficulty. The relative risk of poor sleep outcomes for berry consumers vs. nonconsumers was modelled using population weight-adjusted multivariable general logistic regression.

RESULTS

About 46% of participants reported inadequate sleep duration, and 27% reported sleep difficulties. Twenty-two percent reported consuming berries. Berry consumers had a 10-17% decreased risk of short sleep. The findings were consistent for specific berry types including strawberries and blueberries (p < 0.05). No significant associations with long sleep were found for total berries and any berry types. A decreased risk of sleep difficulties was found to be linked to blackberry consumption (adjusted OR = 0.63, 95% CI: 0.40-0.97; p = 0.036) but not for other berries.

CONCLUSIONS

US adult berry consumers had a decreased risk of reporting short sleep compared to nonconsumers. Berries are underconsumed foods in the US adult population, and increased berry consumption may improve sleep quality.

Healthy sleep practices for shift workers: consensus sleep hygiene guidelines using a Delphi methodology

STUDY OBJECTIVES

The unique requirements of shift work, such as sleeping and working at variable times, mean that current sleep hygiene guidelines may be inappropriate for shift workers. Current guidelines may also contradict fatigue management advice (e.g. advising against daytime napping). The present study utilized a Delphi methodology to determine expert opinion regarding the applicability of current guidelines for shift workers, the appropriateness of the term "sleep hygiene," and develop tailored guidelines for shift workers.

METHODS

The research team reviewed current guidelines and existing evidence to draft tailored guidelines. Seventeen individual guidelines, covering sleep scheduling, napping, sleep environment, bedtime routine, substances, light exposure, diet, and exercise were drafted. Experts from sleep, shift work, and occupational health fields (n = 155) were invited to review the draft guidelines using a Delphi methodology. In each round, experts voted on individual guidelines, with 70% agreement considered consensus. Where consensus was not reached, written feedback from experts was discussed and incorporated into subsequent iterations.

RESULTS

Of the experts invited, 68 (44%) agreed to participate, with 55 (35%) completing the third (final) round. Most experts (84%) agreed that tailored guidelines were required for shift workers. Consensus was reached on all guidelines after three rounds. One additional guideline (sleep inertia) and an introductory statement were developed, resulting in a final set of 18 individual guidelines, termed "healthy sleep practices for shift workers."

CONCLUSIONS

This is the first study to develop tailored sleep hygiene guidelines for shift workers. Future research should investigate the acceptability and effectiveness of these guidelines amongst shift workers.

The effect of light therapy on sleep disorders and psychobehavioral symptoms in patients with Alzheimer's disease: A meta-analysis

BACKGROUND

Although Alzheimer's disease (AD) mainly affects cognitive function, it is often accompanied by sleep disorders and psychobehavioral symptoms. These symptoms, including depression, agitation, and psychotic symptoms, are prominent hospitalization causes among patients with AD. Currently, relatively more research exists on light therapy for sleep disorders, while those on psychobehavioral symptoms are gradually increasing. However, no consensus exists on these results because of the vulnerability of light therapy to multiple factors, including light intensity and duration. Thus, further research investigating this aspect is warranted.

OBJECTIVE

To evaluate the efficacy of light therapy in improving sleep disorders and psychobehavioural symptoms in patients with AD.

METHODS

In this meta-analysis, relevant literature was searched in Embase, the Clinical Trials Registry, Web of Science, PubMed, and the Cochrane Library up to December 2022. Furthermore, a fixed-effects model was used for data analysis.

RESULTS

Fifteen randomized controlled trials involving 598 patients with AD were included. In the case of sleep disorders, our meta-analysis revealed that light therapy significantly improved sleep efficiency (MD = -2.42, 95% CI = -3.37 to -1.48, p < 0.00001), increased interdaily stability (MD = -0.04, 95% CI = -0.05 to -0.03, p < 0.00001), and reduced intradaily variability (MD = -0.07, 95% CI = -0.10 to -0.05, p < 0.00001). With respect to psychotic behavior, light therapy was found to alleviate depression (MD = -2.55, 95% CI = -2.98 to -2.12, p < 0.00001) as well as reduce agitation (MD = -3.97, 95% CI = -5.09 to -2.84, p < 0.00001) and caregiver burden (MD = -3.57, 95% CI = -5.28 to -1.87, p < 0.00001).

CONCLUSION

Light therapy leads to significant improvement in sleep and psychobehavioral symptoms and is associated with relatively fewer side effects in patients with AD, indicating its potential as a promising treatment option for AD.

Toll-like Receptor 2-Melatonin Feedback Loop Regulates the Activation of Spinal NLRP3 Inflammasome in Morphine-Tolerant Rats

BACKGROUND AND PURPOSE

Morphine is amongst the most effective analgesics available for the management of severe pain. However, prolonged morphine treatment leads to analgesic tolerance which limits its clinical usage. Previous studies have demonstrated that melatonin ameliorates morphine tolerance by reducing neuroinflammation. However, little is known about the relationship between Toll like receptor 2 (TLR2) and neuroinflammation in morphine tolerance. The aim of this study was to explore the role of TLR2 in morphine tolerance and its connections with melatonin and Nod-like receptor protein 3 (NLRP3) inflammasome.

METHODS

Sprague-Dawley rats were treated with morphine for 7 days and tail-flick latency test was performed to identify the induction of analgesic tolerance. The roles of TLR2 in microglia activation and morphine tolerance were assessed pharmacologically, and the possible interactions between melatonin, TLR2 and NLRP3 inflammasome were investigated.

KEY RESULTS

Morphine tolerance was accompanied by increased TLR2 expression and NLRP3 inflammasome activation in spinal cord. whereas melatonin level was down-regulated. Chronic melatonin administration resulted in a reduced TLR2 expression and NLRP3 inflammasome activation. Moreover, the analgesic effect of morphine was partially restored. Inhibition of TLR2 suppressed the microglia and NLRP3 inflammasome activation, as well as restored the spinal melatonin level while attenuated the development of morphine tolerance. Furthermore, the inhibition of microglia activation ameliorated morphine tolerance via inhibiting TLR2-NLRP3 inflammasome signaling in spinal cord.

CONCLUSION

In this study, we directly demonstrate a TLR2-melatonin negative feedback loop regulating microglia and NLRP3 inflammasome activation during the development of morphine tolerance.

Crosstalk Between Aging, Circadian Rhythm, and Melatonin

Circadian rhythms (CRs) are 24-hour periodic oscillations governed by an endogenous circadian pacemaker located in the suprachiasmatic nucleus (SCN), which organizes the physiology and behavior of organisms. Circadian rhythm disruption (CRD) is also indicative of the aging process. In mammals, melatonin is primarily synthesized in the pineal gland and participates in a variety of multifaceted intracellular signaling networks and has been shown to synchronize CRs. Endogenous melatonin synthesis and its release tend to decrease progressively with advancing age. Older individuals experience frequent CR disruption, which hastens the process of aging. A profound understanding of the relationship between CRs and aging has the potential to improve existing treatments and facilitate development of novel chronotherapies that target age-related disorders. This review article aims to examine the circadian regulatory mechanisms in which melatonin plays a key role in signaling. We describe the basic architecture of the molecular circadian clock and its functional decline with age in detail. Furthermore, we discuss the role of melatonin in regulation of the circadian pacemaker and redox homeostasis during aging. Moreover, we also discuss the protective effect of exogenous melatonin supplementation in age-dependent CR disruption, which sheds light on this pleiotropic molecule and how it can be used as an effective chronotherapeutic medicine.

The effects of light therapy on depression and sleep in women during pregnancy or the postpartum period: A systematic review and meta-analysis

BACKGROUND

In recent years, light therapy has been tried for the treatment of depression and sleep in pregnancy or postnatal period women, but the results have been inconclusive. This meta-analysis is the first to systematically review the effects of light therapy on depression and sleep disturbances in women during pregnancy and the postnatal period.

METHODS

We searched for randomized controlled studies in PubMed, Embase, Cochrane Library, Web of Science, Chinese National Knowledge Infrastructure, and Chinese Biomedical Database up to January 2023. The standardized mean difference (SMD) was used to assess the efficacy of the outcome indicators.

RESULTS

Eight studies were eventually included in the analysis. The results showed that light therapy was more effective than the placebo group in terms of depression (SMD = .34, CI = .08-.61) and sleep (SMD = .64,95%CI = .28-1.00). Subgroup analysis could not explain the significant heterogeneity. There were no serious adverse effects in either the light therapy or placebo groups.

CONCLUSIONS

Light therapy could be considered an effective treatment for depression and sleep disturbances in women during pregnancy and the postnatal period. However, future high-quality trials with larger sample sizes are still needed.

Unveiling the sleep-cardiovascular connection: Novel perspectives and interventions-A narrative review

Introduction

Sleep is an important neurophysiological condition that is intricately linked to general health, laying the basis for both physiological and psychological well-being. A thorough examination of sleep disorders and cardiovascular health demonstrates their deep relationship, emphasizing the numerous diagnostic tools and treatment techniques available.

Aim

This study aims to examine the impact, mechanisms, diagnostic techniques, treatment strategies, implications, and healthcare interventions of the sleep-cardiovascular connection, to better understand the relationship between sleep disorders and cardiovascular health.

Methods

The paper reviews key studies conducted from 2015-till date, investigating the impact of sleep disorders on the cardiovascular system. It looked into data relating to cardiovascular outcomes based on the degree of sleep disorders, considered potential confounding factors, and addressed current research constraints.

Results

The findings highlight a strong link between sleep problems and poor cardiovascular outcomes. Emerging diagnostic tools, such as enhanced sleep-related technology and biomarkers, open up new avenues for determining the impact of sleep disturbances on cardiovascular health. In addition, the research discusses several treatment options, ranging from cognitive behavioral therapy to pharmaceutical therapies, and their potential benefits in addressing sleep-related cardiovascular risks.

Conclusion

The complex association between sleep disturbances and cardiovascular health emphasizes the need to recognize sleep as a critical component of overall well-being. Thus collaboration among medical disciplines, as well as individualized therapies, are critical to improving patient care. Moreover, Understanding and managing the consequences of sleep problems on cardiovascular health can lead to more effective interventions, better outcomes, and improved public health as research advances.

Increasing of Cortisol Level and Neutrophil-Lymphocyte-Ratio are Associated with Severity Level and Sleep Disturbances in Acute Ischemic Stroke

Background

Acute ischemic stroke can cause sleep disturbances. These complaints involve various factors, such as disturbances of the hormone cortisol and Neutrophil-Lymphocyte-Ratio (NLR) that can cause increasing severity levels in acute ischemic stroke patients. This study aimed to determine the relationship between cortisol levels and NLR with severity levels and sleep disturbances in acute ischemic stroke patients.

Methods

A cross-sectional analytic observational study was conducted on acute ischemic stroke patients during Agustus - December 2022. Examine cortisol levels using the ELISA method, NLR from blood test, asses severity levels using the National Institute of Health Stroke Scale (NIHSS), and The Pittsburgh Sleep Questionnaire Index (PSQI) is used as a measure for the initial screening of sleep disturbances-statistical analysis using Spearman correlation.

Results

Total study subjects were 48 patients, with the majority 62.5% women; the mean age of study subjects was above 60 years (56.3%), and the most common type of stroke was large artery atherosclerotic stroke (77.1%), the highest NIHSS score was in the moderate category (85.4%), the most common risk factor is hypertension (64.4%), and basal ganglia area is the most common ischemic stroke location (52.1%). There was a positive correlation between cortisol levels with NIHSS (r=0.874; p-value <0.001), NLR with sleep disturbances (r=0.829; p-value<0.001), NLR with NIHSS (r=0.893; p-value<0.001), and NIHSS with PSQI (r=0.836; p-value<0.001).

Conclusion

There were a positive correlation between cortisol level, NLR level, and NIHSS score with sleep quality disturbances based on PSQI in acute ischemic stroke patients.