Melatonin: Physiological effects in humans. Neurochirurgie. 2015;61:77-84. [PMID: 25908646 DOI: 10.1016/j.neuchi.2015.03.002]

Fiat Lux: Light and Pedagogy for the 21st Century

Background

The relationship between the quality of the learning environment and student outcomes is receiving more serious attention from educational psychologists, neurologists, ophthalmologists, orthopedists, surgeons, oncologists, architects, ergonomists, nutritionists, and Michelin star chefs. There is a role for ergonomic office and school design to positively impact worker and student productivity, and one design attribute drawing attention is the indoor lit environment. In this review, we expand upon the role that light plays in education, as it has enabled millions of pupils to read at late hours, which were previously too dark. However, still unappreciated is the biological effects of artificial light on circadian rhythm and its subsequent impacts on health and learning outcomes.

Summary

This review describes the current state of light in the educational environment, its impact, and the effect of certain inexpensive and easy-to-implement adaptations to better support student growth, learning and development. We find that the current lighting environment for pupils is sub-optima based on biological mechanism and may be improved through cost effective interventions. These interventions can achieve greater biological harmonization and improve learner outcomes.

Key Message

The impact of the lighting environment in educational institutions on pupil biology has received minimal attention thus far. The current lighting environment in schools is not conducive to student health and educational performance. Cost-effective approaches can have an outsized impact on student health and educational attainment. We strongly recommend educational institutions take the lit environment into account when designing educational programs.

Pancreatic melatonin enhances anti-tumor immunity in pancreatic adenocarcinoma through regulating tumor-associated neutrophils infiltration and NETosis

Tumor microenvironment contributes to poor prognosis of pancreatic adenocarcinoma (PAAD) patients. Proper regulation could improve survival. Melatonin is an endogenous hormone that delivers multiple bioactivities. Here we showed that pancreatic melatonin level is associated with patients' survival. In PAAD mice models, melatonin supplementation suppressed tumor growth, while blockade of melatonin pathway exacerbated tumor progression. This anti-tumor effect was independent of cytotoxicity but associated with tumor-associated neutrophils (TANs), and TANs depletion reversed effects of melatonin. Melatonin induced TANs infiltration and activation, therefore induced cell apoptosis of PAAD cells. Cytokine arrays revealed that melatonin had minimal impact on neutrophils but induced secretion of Cxcl2 from tumor cells. Knockdown of Cxcl2 in tumor cells abolished neutrophil migration and activation. Melatonin-induced neutrophils presented an N1-like anti-tumor phenotype, with increased neutrophil extracellular traps (NETs) causing tumor cell apoptosis through cell-to-cell contact. Proteomics analysis revealed that this reactive oxygen species (ROS)-mediated inhibition was fueled by fatty acid oxidation (FAO) in neutrophils, while FAO inhibitor abolished the anti-tumor effect. Analysis of PAAD patient specimens revealed that CXCL2 expression was associated with neutrophil infiltration. CXCL2, or TANs, combined with NET marker, can better predict patients' prognosis. Collectively, we discovered an anti-tumor mechanism of melatonin through recruiting N1-neutrophils and beneficial NET formation.

Postoperative Delirium in Patients Receiving Hip Bipolar Hemiarthroplasty for Displaced Femoral Neck Fractures: The Risk Factors and Further Clinical Outcomes

BACKGROUND

Postoperative delirium in patients who have hip fractures may lead to poor outcomes. This study aimed to determine perioperative risk factors and clinical outcomes of postoperative delirium in patients undergoing hip bipolar hemiarthroplasty for displaced femoral neck fractures.

METHODS

Among 1,353 patients who underwent hemiarthroplasty at our institution during 2013-2021, we identified 78 patients with postoperative delirium diagnosed with the confusion assessment method. The mean delirium duration was 28 hours (range: 15-520). We also included 1:2 sex- and age-matched patients who did not have postoperative delirium after the same surgery as a matching cohort for comparison. Patient comorbidities, perioperative data, delirium occurrence, and outcomes were collected for analyses.

RESULTS

A Charlson Comorbidity Index (CCI) score ≥6 (odds ratio (OR): 2.08, P = .017), nighttime surgery (OR: 3.47, p =<.001), surgical delays (OR: 1.01, P = .012), preoperative anemia (OR: 2.1, P = .012), and blood transfusions (OR: 2.47, P = .01) may increase the risk of postoperative delirium. The presentation of delirium was associated with sepsis (OR: 3.77, P = .04), longer hospital stays (P < .001), higher 1-year mortality (OR: 3.97, P = .002), and overall mortality (OR: 2.1, P = .02).

CONCLUSION

Postoperative delirium predicted poor outcomes. Our results emphasized the importance of early identification of patients at risk and optimization of the medical conditions before and after surgery.

Ramelteon for delirium prevention in hospitalized patients: An updated meta-analysis and trial sequential analysis of randomized controlled trials

Although ramelteon has been examined as a relatively new therapeutic option for delirium prevention, current evidence to evaluate its efficacy is limited. We conducted an updated meta-analysis and examine the reliability of existing evidence regarding the effect of ramelteon on delirium prevention in hospitalized patients. Seven major electronic databases were systematically searched to identify randomized controlled trials examining the efficacy of ramelteon in delirium prevention. Data were pooled using a frequentist-restricted maximum-likelihood random-effects model. A trial sequential analysis was performed using relative risk reduction thresholds of 50%. The primary outcome was the incidence of delirium (reported as odds ratio with 95% confidence intervals). The secondary outcomes were the days of delirium, all-cause mortality, and all-cause discontinuation. Of 187 potentially eligible studies identified, 8 placebo-controlled randomized controlled trials (n = 587) were included. This updated meta-analysis showed that ramelteon was associated with lower odds of delirium occurrence than placebo (0.50; 0.29-0.86; I²  = 17.48%). In trial sequential analysis, the effect of ramelteon across the superiority boundary when using a relative risk reduction threshold ranging from 40% to 60%. In subgroup analyses, ramelteon compared with placebo was associated with lower odds of delirium occurrence in the elderly group (k = 5; 0.28; 0.09-0.85; I²  = 27.93%) and multiple dosage group (k = 5; 0.34; 0.14-0.82; I²  = 44.24%) but not in the non-elderly and non-multiple dosage groups. When considering surgical patients and medical patients separately, ramelteon showed a trend in the treatment of delirium prevention in both groups, while these findings were not statistically significant. No significant between-group differences were found in the secondary outcomes. The current meta-analysis provides updated and reliable evidence that ramelteon, in comparison with placebo, reduces the risk of delirium among hospitalized patients.

Melatonin improved glucose homeostasis is associated with the reprogrammed gut microbiota and reduced fecal levels of short-chain fatty acids in db/db mice

Accumulated evidence shows that melatonin possesses the potential to improve lipid metabolism by modifying gut microbiota and glucose metabolism via regulating the melatonin receptor signaling pathway. However, the contribution of melatonin consumption on glucose homeostasis by affecting gut microbiota has not been investigated in diabetes. In the current work, we investigated the effect of melatonin administration on gut microbiota and glucose homeostasis in db/db mice, a type 2 diabetes model with leptin receptor deficiency. Administration of melatonin through drinking water (at 0.25% and 0.50%) for 12 weeks decreased diabetic polydipsia and polyuria, increased insulin sensitivity and impeded glycemia. The accumulated fecal levels of total short-chain fatty acids (SCFAs) and acetic acid are positively correlated with diabetes-related parameters-homeostasis model assessment of insulin resistance (HOMA-IR) index and fasting blood glucose (FBG) level. The reprogramming of gut microbiota structure and abundance and the reduction of fecal levels of SCFAs, including acetic acid, butyric acid, isovaleric acid, caproic acid, and isobutyric acid, by melatonin may be beneficial for enhancing insulin sensitivity and lowering FBG, which were verified by the results of correlation analysis between acetic acid or total SCFAs and HOMA-IR and FBG. In addition, the melatonin downregulated hepatic genes, including fructose-1,6-bisphosphatase 1, forkhead box O1 alpha, thioredoxin-interacting protein, phosphoenolpyruvate carboxy-kinase (PEPCK), PEPCK1 and a glucose-6-phosphatase catalytic subunit, that responsible for gluconeogenesis support the result that melatonin improved glucose metabolism. Overall, results showed that the melatonin supplementation reduced fecal SCFAs level via reprogramming of gut microbiota, and the reduction of fecal SCFAs level is associated with improved glucose homeostasis in db/db mice.

Gut microbiota-derived melatonin from Puerariae Lobatae Radix-resistant starch supplementation attenuates ischemic stroke injury via a positive microbial co-occurrence pattern

Ischemic stroke is closely associated with gut microbiota dysbiosis and intestinal barrier dysfunction. Prebiotic intervention could modulate the intestinal microbiota, thus considered a practical strategy for neurological disorders. Puerariae Lobatae Radix-resistant starch (PLR-RS) is a potential novel prebiotic; however, its role in ischemic stroke remains unknown. This study aimed to clarify the effects and underlying mechanisms of PLR-RS in ischemic stroke. Middle cerebral artery occlusion surgery was performed to establish a model of ischemic stroke in rats. After gavage for 14 days, PLR-RS attenuated ischemic stroke-induced brain impairment and gut barrier dysfunction. Moreover, PLR-RS rescued gut microbiota dysbiosis and enriched Akkermansia and Bifidobacterium. We transplanted the fecal microbiota from PLR-RS-treated rats into rats with ischemic stroke and found that the brain and colon damage were also ameliorated. Notably, we found that PLR-RS promoted the gut microbiota to produce a higher level of melatonin. Intriguingly, exogenous gavage of melatonin attenuated ischemic stroke injury. In particular, melatonin attenuated brain impairment via a positive co-occurrence pattern in the intestinal microecology. Specific beneficial bacteria served as leaders or keystone species to promoted gut homeostasis, such as Enterobacter, Bacteroidales_S24-7_group, Prevotella_9, Ruminococcaceae and Lachnospiraceae. Thus, this new underlying mechanism could explain that the therapeutic efficacy of PLR-RS on ischemic stroke at least partly attributed to gut microbiota-derived melatonin. In summary, improving intestinal microecology by prebiotic intervention and melatonin supplementation in the gut were found to be effective therapies for ischemic stroke.

The Role of Dietary Antioxidants and Their Potential Mechanisms in Alzheimer’s Disease Treatment

Alzheimer’s disease (AD) is a progressive neurodegenerative disorder associated with cognitive decline and characterized by amyloid-β plaques and neurofibrillary tau tangles. Although AD’s exact pathophysiology remains unclear, oxidative stress is known to play a role in the neurodegenerative process. Since no curative treatment exists, antioxidants represent a potential treatment for AD due to their ability to modulate oxidative stress. Therefore, this review aims to examine the impact of antioxidant supplementation and its potential mechanisms on cognitive function. The review primarily discusses research articles published between 2012 and 2022 reporting the results of clinical trials involving antioxidant supplementation on cognitive function in individuals with AD. Antioxidant supplementation included probiotics, selenium, melatonin, resveratrol, rosmarinic acid, carotenoids, curcumin, vitamin E, and coenzyme Q. While the studies included in this review did not provide much evidence for the beneficial role of antioxidant supplements on cognitive function in AD, the results varied from antioxidant to antioxidant and among trials examining the same antioxidant. Furthermore, many of the studies’ findings face several limitations, including short trial durations, small sample sizes, and a lack of diversity among study participants. As a result, more research is required to examine the impact of antioxidant supplementation on cognitive function in AD.

Preliminary screening of biomarkers in HAPE based on quasi-targeted metabolomics

High altitude pulmonary edema (HAPE) is a serious threat to the physical and mental health of people who quickly enter high plateaus, deserves more attention and in-depth research. In our study, through the detection of various physiological indexes and other phenotypes in a HAPE rat model, the HAPE group showed a significant decrease in oxygen partial pressure and oxygen saturation, and a significant increase in pulmonary artery pressure and lung tissue water content. The lung histomorphology showed characteristics such as pulmonary interstitial thickening and inflammatory cell infiltration. We applied quasi-targeted metabolomics to compare and analyze the components of metabolites in arterial–veinous blood in control rats and HAPE rats. Using kyoto Encyclopedia of Genes Genomes (KEGG) enrichment analysis and two machine algorithms, we speculate that after hypoxic stress and comparing arterial blood and venous blood products in rats, the metabolites were richer, indicating that normal physiological activities, such as metabolism and pulmonary circulationhad a greater impact after hypoxic stress; D-mannoseDOWN, oxidized glutathioneDOWN, glutathione disulfideDOWN, and dehydrocholic acidDOWN in arterial blood play key roles in predicting the occurrence of HAPE; in venous blood, L-leucineDOWN, L-thyroxineDOWN, and cis-4-hydroxy- D-prolineDOWN may have key roles, which can be considered biomarkers of HAPE. This result provides a new perspective for the further diagnosis and treatment of plateau disease and lays a strong foundation for further research.

Melatonin Treatment in Kidney Diseases

Melatonin is a neurohormone that is mainly secreted by the pineal gland. It coordinates the work of the superior biological clock and consequently affects many processes in the human body. Disorders of the waking and sleeping period result in nervous system imbalance and generate metabolic and endocrine derangements. The purpose of this review is to provide information regarding the potential benefits of melatonin use, particularly in kidney diseases. The impact on the cardiovascular system, diabetes, and homeostasis causes melatonin to be indirectly connected to kidney function and quality of life in people with chronic kidney disease. Moreover, there are numerous reports showing that melatonin plays a role as an antioxidant, free radical scavenger, and cytoprotective agent. This means that the supplementation of melatonin can be helpful in almost every type of kidney injury because inflammation, apoptosis, and oxidative stress occur, regardless of the mechanism. The administration of melatonin has a renoprotective effect and inhibits the progression of complications connected to renal failure. It is very important that exogenous melatonin supplementation is well tolerated and that the number of side effects caused by this type of treatment is low.

UPLC-MS/MS simultaneous quantification of urinary circadian rhythm hormones and related metabolites: Application to air traffic controllers

Civil aviation flight crew and civil aviation air traffic controllers are prone to circadian rhythm abnormalities, which can lead to a slew of other maladies. It could endanger people's health and provide a serious threat to the safety of civil aviation flights if it is not appropriately evaluated and addressed. Early detection of rhythm irregularities and prompt treatment for particular populations that are vulnerable to rhythm disorders are crucial for enhancing civil aviation safety. In general, monitoring of the classical circadian rhythm biomarkers (melatonin or cortisol) in plasma or saliva is an effective way to evaluate the rhythm status. Due to the challenging sample procedure and the trauma of plasma, urine sample testing has received an increasing amount of attention. While, urine circadian rhythm biomarkers have seldom been examined, and the relationship between urinary steroid hormones and melatonin is still poorly understood. In most cases, hormones are determined by immunoassays respectively, mainly enzyme-linked immunosorbent assay (ELISA) or radioimmunoassay (RIA). There are also reports describing the liquid chromatography with tandem mass spectrometry (LC-MS/MS) technique as a method of melatonin or few steroid hormones quantification, however, the simultaneous detection of multiple rhythmic hormones in human urine is rarely reported. For the quantification of the rhythmic hormones in human urine, an accurate approach using ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was devised in this work. Nine endogenous hormones (melatonin, 6-hydroxymelatonin, 6-sulfatoxymelatonin, cortisol, corticosterone, cortisone, testosterone, epitestosterone and androsterone), in human overnight urine, were quantified after solid phase extraction (SPE). A reverse phase HSS C18 column was used for chromatographic separation with a 9-minute gradient elution and deuterated analogues of each analyte were applied as internal standards. This method was successfully applied to the analysis of 596 overnight urine samples (23:00-9:00) collected from 84 air traffic controllers in the Beijing area during shift work. This study's findings showed a clear correlation not only between melatonin and its metabolites; cortisol-related metabolites, but also between melatonin metabolites and endogenous metabolites upstream and downstream of cortisol, implying that these two categories of hormones can be used as potential biological rhythm indicators to provide circadian rhythm data support for future studies on circadian rhythm disorders.

Melatonin attenuates cardiopulmonary toxicity induced by benzo(a)pyrene in mice focusing on apoptosis and autophagy pathways

Benzo(a)pyrene (BaP) is a polycyclic aromatic hydrocarbon and a serious environmental pollutant. BaP is formed by the incomplete combustion of organic matter at high temperatures. In addition, tobacco smoke and many foods, especially charbroiled food and grilled meats, contain BaP and can cause it to enter human body. Melatonin, a pineal gland hormone, has antioxidant, anti-apoptosis, and autophagy regulatory properties. The possible protective impact of melatonin on cardiopulmonary toxicity induced by BaP was investigated by examining the antioxidant effects and the apoptosis and autophagy properties of melatonin. Thirty male mice were divided into 5 groups and treated for 28 days as follows: (I) control (BaP and melatonin solvent), (II) BaP (75 mg/kg, oral gavage), (III and IV) BaP (75 mg/kg) + melatonin (10 and 20 mg/kg, intraperitoneally), (V) melatonin (20 mg/kg). The oxidative stress factors (MDA and GSH content) were assessed in the heart and lung tissues. The levels of apoptotic (Caspase-3 and the Bax/Bcl-2 ratio) and autophagic (the LC3 ӀӀ/Ӏ, Beclin-1, and Sirt1) proteins were examined by using western blot analysis. Following the administration of BaP, MDA, the Bax/Bcl-2 ratio, and the Caspase-3 proteins increased in the heart and lung tissues, while GSH, Sirt1, Beclin-1, and the LC3 II/I ratio diminished. The coadministration of melatonin along with BaP, MDA, and apoptotic proteins returned to the control values, while GSH and the autophagy proteins were enhanced in both the heart and lungs. Melatonin exhibited a protective effect against BaP-induced heart and lung injury through the suppression of oxidative stress and apoptosis and the induction of the Sirt1/autophagy pathway.

Efficacy of Melatonin for Insomnia in Children with Autism Spectrum Disorder: A Meta-analysis

AIM

 This study aimed to evaluate the effectiveness of melatonin in treating insomnia in children with autism spectrum disorder (ASD).

METHODS

 Comprehensive searches were conducted in the PubMed, EMBASE, and Web of Science databases from their inception to April 20, 2022. Data were extracted and assessed for quality by two researchers. Statistical analysis was performed using the Stata 15.0 software.

RESULTS

 Four studies including 238 patients were included. The results showed that compared with the control group, melatonin could shorten the sleep-onset latency (standardized mean difference [SMD] = - 1.34, 95% CI: -2.19 to -0.48), reduce the number of awakenings (SMD = -2.35, 95% CI: -4.62 to -0.08), and prolong the total sleep time (SMD = 1.42, 95% CI: 0.5-2.33) in children with ASD.

CONCLUSION

 Melatonin has a certain effect on relieving sleep disturbances in children with ASD, which can shorten sleep latency, reduce the number of awakenings, and prolong total sleep time. Larger studies are required to verify this hypothesis.

Effect of massage therapy on sleep quality in critically ill patients: A systematic review and meta-analysis

AIM

The aim of the study was to compare the effects of massage interventions on sleep quality among patients in the adult critical care unit.

BACKGROUND

Massage interventions have positive effects when applied to manage sleep quality in critical care units. However, research identifying the effect of massage intervention is limited.

DESIGN

This study adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines.

METHODS

Five databases were searched from their inception to 15 April 2022 (the last search was conducted on 15 November 2022, but it yielded no additional eligible studies). The literature search was conducted using Embase, MEDLINE, the Cochrane Library, CINAHL, PsycINFO and additional sources such as Google Scholar. The Cochrane risk of bias tool for randomised trials (RoB 2.0) was used to assess the risk of bias. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) system assessed the certainty of evidence and recommendations.

RESULTS

In total, ten randomised controlled trials comprising 569 participants were used in the systematic review, and eight trials were included in the meta-analysis. Subgroup analysis revealed significant effects of foot reflexology massage on subjective sleep quality. Massage therapy for a two-night duration in cardiac care unit patients exhibited a significant effect on subjective sleep quality. The overall GRADE certainty of evidence was low.

CONCLUSION

Massage intervention, particularly foot reflexology massage, with a two-night duration showed improvement in subjective sleep quality among critically ill patients. Although evidence quality was low, the results suggest that massage interventions provide a non-invasive, low-cost and effective way to promote sleep quality in critically ill adult patients.

RELEVANCE TO CLINICAL PRACTICE

Massage interventions can enable nurses to recommend and implement strategies promoting and improving sleep quality among critically ill patients.

STUDY REGISTRATION

The review protocol was registered a priori and published online in the PROSPERO database of systematic reviews (www.crd.York.ac.uk/Prospero with the registration number # CRD42022332371).

PATIENT OR PUBLIC CONTRIBUTION

No patient or public contribution if such details are not necessary or do not apply to your work and state why.

Seasonal variations of nonmotor symptoms in patients with Parkinson's disease in Southeast China

BACKGROUND

Studies suggest seasonal fluctuations of symptoms in Parkinson's disease (PD) patients in Western countries. However, the association between seasonal change and variation in nonmotor symptoms (NMS) in Chinese PD patients is unclear. Here, we studied whether there is a change rule with annual cycle with severity of NMS for patients with PD in Southeast China.

METHODS

We studied 1005 PD patients between April 2008 and October 2020. Patients were classified into four seasons according to the 24 Chinese solar terms, based on assessment date. We compared comprehensive NMS scales and polysomnography parameters among groups and conducted further analysis of disease severity.

RESULTS

Among the 1005 patients studied, the mean age was 64.2 ± 9.7 years and 569 (56.6%) of them were men. Relative to the summer group, patients assessed during winter had higher Scales for Outcomes in Parkinson's disease-Autonomic Dysfunction (SCOPA-AUT) scores ( P  = 0.045). The sleep efficiency factor scores of Pittsburgh Sleep Quality Index in patients were higher during spring than summer ( P  = 0.009). Among patients who completed polysomnography during the same period ( n  = 135), compared with summer follow-ups, we observed a higher percentage of NREMS1 in winter and spring follow-ups ( P  = 0.042, P  = 0.011), a higher NREMS1 time in spring follow-ups ( P  = 0.0024), a lower NREMS2 time in winter follow-ups ( P  = 0.007), and a higher percentage of phasic rapid eye movement (REM)-sleep without atonia in autumn and winter follow-ups ( P  = 0.026 and P  = 0.020, respectively). In a subset of patients with PD and REM sleep behavior disorder (RBD; n  = 182), those visited during winter had higher scores for RBD questionnaire-Hong Kong and its factor 1 (dream-related sub-score) than those visited during summer ( P  = 0.034, P  = 0.020). We observed similar findings for SCOPA-AUT and sleep efficiency factor scores in early stage patients in subgroup analysis.

CONCLUSIONS

PD patients assessed for follow-up during summer showed less severe symptoms of autonomic dysfunction and RBD symptoms than those assessed in winter, and less sleep disturbance than those in spring and winter, suggesting that seasonal change and NMS fluctuation are related, especially in patients with early stage PD.

Berberine Ameliorates Metabolic-Associated Fatty Liver Disease Mediated Metabolism Disorder and Redox Homeostasis by Upregulating Clock Genes: Clock and Bmal1 Expressions

Metabolic-associated fatty liver disease (MAFLD) is one of the most common chronic liver diseases, which in turn triggers mild inflammation, metabolic dysfunction, fibrosis, and even cancer. Accumulating evidence has suggested that Berberine (BBR) could significantly improve MAFLD progression. Clock and Bmal1 as heterodimer proteins highly participated in the development of MAFLD, but whether BBR targets Clock and Bmal1 in MAFLD remains poorly understood. The result suggested that the protein levels of Clock and Bmal1 were decreased in MAFLD mice, which was negatively correlated with elevated reactive oxygen species (ROS) accumulation, the H2O2 level, liver inflammation, metabolic dysfunction, and insulin resistance. The mRNA and protein levels of Clock and Bmal1 were also decreased in glucosamine-induced HepG2 cells, which were are negatively related to glucose uptake, the ROS level, and the H2O2 level. More importantly, Bmal1 siRNA could mimic the effect of glucosamine in HepG2 cells. Interestingly, Berberine (BBR) could rescue metabolism disorder and redox homeostasis through enhancing Clock and Bmal1 expression in vivo and in vitro. Therefore, BBR might be an effective natural compound for alleviating redox homeostasis, metabolism disorder, and liver pathological changes in MAFLD by activating Clock and Bmal1 expression.

Exploring the Role of Neurotransmitters in Multiple Sclerosis: An Expanded Review

Multiple sclerosis (MS) is a chronic inflammatory and neurodegenerative disease of the central nervous system (CNS). Although emerging evidence has shown that changes in neurotransmitter levels in the synaptic gap may contribute to the pathophysiology of MS, their specific role has not been elucidated yet. In this review, we aim to analyze preclinical and clinical evidence on the structural and functional changes in neurotransmitters in MS and critically discuss their potential role in MS pathophysiology. Preclinical studies have demonstrated that alterations in glutamate metabolism may contribute to MS pathophysiology, by causing excitotoxic neuronal damage. Dysregulated interaction between glutamate and GABA results in synaptic loss. The GABAergic system also plays an important role, by regulating the activity and plasticity of neural networks. Targeting GABAergic/glutamatergic transmission may be effective in fatigue and cognitive impairment in MS. Acetylcholine (ACh) and dopamine can also affect the T-mediated inflammatory responses, thereby being implicated in MS-related neuroinflammation. Also, melatonin might affect the frequency of relapses in MS, by regulating the sleep-wake cycle. Increased levels of nitric oxide in inflammatory lesions of MS patients may be also associated with axonal neuronal degeneration. Therefore, neurotransmitter imbalance may be critically implicated in MS pathophysiology, and future studies are needed for our deeper understanding of their role in MS.

Potential effects of shift work on skin autoimmune diseases

Shift work is associated with systemic chronic inflammation, impaired host and tumor defense and dysregulated immune responses to harmless antigens such as allergens or auto-antigens. Thus, shift workers are at higher risk to develop a systemic autoimmune disease and circadian disruption with sleep impairment seem to be the key underlying mechanisms. Presumably, disturbances of the sleep-wake cycle also drive skin-specific autoimmune diseases, but epidemiological and experimental evidence so far is scarce. This review summarizes the effects of shift work, circadian misalignment, poor sleep, and the effect of potential hormonal mediators such as stress mediators or melatonin on skin barrier functions and on innate and adaptive skin immunity. Human studies as well as animal models were considered. We will also address advantages and potential pitfalls in animal models of shift work, and possible confounders that could drive skin autoimmune diseases in shift workers such as adverse lifestyle habits and psychosocial influences. Finally, we will outline feasible countermeasures that may reduce the risk of systemic and skin autoimmunity in shift workers, as well as treatment options and highlight outstanding questions that should be addressed in future studies.

Mobile Phone Addiction and Sleep Quality among Older People: The Mediating Roles of Depression and Loneliness

Rapid social development has made the elderly increasingly dependent on mobile phones, and mobile phone addiction has a negative effect on sleep quality. The underlying mechanism between the two is unclear. This study examined the mediating role of depression and loneliness in the relationship between phone addiction and sleep quality in older adults. Mobile Phone Addiction Scale Short Version, Pittsburgh Sleep Quality Index scale, UCLA (University of California, Los Angeles)-8 Loneliness Scale, and Short Geriatric Depression Scale (GDS-15) were used to investigate 459 older adults in China. The results showed that there was a positive correlation between mobile phone addiction and sleep quality in the elderly. In addition, depression and loneliness partially mediated the relationship between mobile phone addiction and sleep quality in older adults. The current study provides new insights into the impact of mobile phone addiction on sleep quality and the importance of depression and loneliness in older adults. The limitations and significance of this study are discussed.

Melatonin as a Possible Natural Anti-Viral Compound in Plant Biocontrol

Melatonin is a multifunctional and ubiquitous molecule. In animals, melatonin is a hormone that is involved in a wide range of physiological activities and is also an excellent antioxidant. In plants, it has been considered a master regulator of multiple physiological processes as well as of hormonal homeostasis. Likewise, it is known for its role as a protective biomolecule and activator of tolerance and resistance against biotic and abiotic stress in plants. Since infections by pathogens such as bacteria, fungi and viruses in crops result in large economic losses, interest has been aroused in determining whether melatonin plays a relevant role in plant defense systems against pathogens in general, and against viruses in particular. Currently, several strategies have been applied to combat infection by pathogens, one of them is the use of eco-friendly chemical compounds that induce systemic resistance. Few studies have addressed the use of melatonin as a biocontrol agent for plant diseases caused by viruses. Exogenous melatonin treatments have been used to reduce the incidence of several virus diseases, reducing symptoms, virus titer, and even eradicating the proliferation of viruses such as Tobacco Mosaic Virus, Apple Stem Grooving Virus, Rice Stripe Virus and Alfalfa Mosaic Virus in tomato, apple, rice and eggplant, respectively. The possibilities of using melatonin as a possible natural virus biocontrol agent are discussed.

The effect of reducing blue light from smartphone screen on subjective quality of sleep among students

The exposure of humans to artificial light at night (ALAN) with predominant blue part of the visible spectrum is strongly influencing circadian rhythm and sleep through melanopsin-containing retinal ganglion cells (RGC). We hypothesized that reducing the amount of emitted blue light from screens of mobile phones during the night will increase sleep quality in our student population. The aim of the work was to investigate the effect of reducing blue light from smartphone screen during the night on subjective quality of sleep among students of medicine. The target population was students of medicine aged 20 to 22 years old of both sexes. The primary outcome of the study was subjective sleep quality, assessed by the Serbian version of the Pittsburgh Sleep Quality Index (PSQI). The mean total PSQI score before intervention was 6.83 ± 2.73 (bad), while after the intervention the same score was statistically significant reduced to 3.93 ± 1.68 (good) with large effect size. The study has shown that a reduction of blue light emission from LED backlight screens of mobile phones during the night leads to improved subjective quality of sleep in students, as well as improvement in daytime functioning and going to sleep.

Melatonin ameliorates chronic copper-induced lung injury

Copper (Cu) is an important trace element required for several biological processes. The use of copper is increasing gradually in several applications. Previous studies suggest that excess levels of copper are attributed to induce oxidative stress and inflammation, mediating tissue damage. Inline, melatonin the hormone of darkness has been reported to exhibit various therapeutic effects including strong free radical scavenging properties and anti-inflammatory effects. However, its effects against pulmonary injury promoted by copper are not explored and remain unclear so far. Therefore, the present study was aimed to investigate the protective effect of melatonin against copper-induced lung damage. Female Sprague Dawley (SD) rats were exposed to 250 ppm of copper in drinking water for 16 weeks and treated with melatonin (i.p.) 5 and 10 mg/kg from the week (13-16th). The extent of tissue damage was assessed by tissue oxidative stress parameters, metal estimation and histological analysis. Copper-challenged rats showed altered oxidative stress variables. In addition, metal analysis revealed increased copper accumulation in the lungs and histological staining results further indicated severe tissue injury and inflammatory cell infiltration in copper-exposed rats. To this side, treatment with melatonin showed antioxidant and anti-inflammatory activities evidenced by reduced oxidative stress, tissue inflammation and collagen deposition as compared to copper-exposed animals. Moreover, spectral findings suggested melatonin treatment modulated the frequency sift, as compared to copper-challenged animals. Altogether, the present results suggest that melatonin might play a potential role in preventing copper-induced lung aberrations via inhibiting the ROS-mediated oxidative stress and inflammation.

Melatonin: A potential adjuvant therapy for septic myopathy

Septic myopathy, also known as ICU acquired weakness (ICU-AW), is a characteristic clinical symptom of patients with sepsis, mainly manifested as skeletal muscle weakness and muscular atrophy, which affects the respiratory and motor systems of patients, reduces the quality of life, and even threatens the survival of patients. Melatonin is one of the hormones secreted by the pineal gland. Previous studies have found that melatonin has anti-inflammatory, free radical scavenging, antioxidant stress, autophagic lysosome regulation, mitochondrial protection, and other multiple biological functions and plays a protective role in sepsis-related multiple organ dysfunction. Given the results of previous studies, we believe that melatonin may play an excellent regulatory role in the repair and regeneration of skeletal muscle atrophy in septic myopathy. Melatonin, as an over-the-counter drug, has the potential to be an early, complementary treatment for clinical trials. Based on previous research results, this article aims to critically discuss and review the effects of melatonin on sepsis and skeletal muscle depletion.

Melatonin: a potential therapeutic approach for the management of primary Sjögren's syndrome

Primary Sjögren's syndrome (pSS) is an autoimmune disease that primarily affects the exocrine glands and is mainly characterized by sicca symptoms of the eyes and mouth. Approximately 30-50% of pSS patients develop systemic multi-organ disorders including malignant lymphoma. The etiology of pSS is not well understood; growing evidence suggests that uncontrolled immune/inflammatory responses, excessive oxidative stress, defected apoptosis, dysregulated autophagy, exosomes, and exogenous virus infections may participate in the pathogenesis of pSS. There is no ideal therapeutic method for pSS; the management of pSS is mainly palliative, which aims to alleviate sicca symptoms. Melatonin, as the main secretory product of the pineal gland, has been evidenced to show various physiological functions, including effects of immunoregulation, capability of antioxidation, moderation of autophagy, suppressive activities of apoptosis, regulative capacity of exosomes, properties of anti-infection, and improvement of sleep. The beneficial effects of melatonin have been already validated in some autoimmune diseases such as multiple sclerosis (MS), type 1 diabetes mellitus (T1DM), systemic lupus erythematosus (SLE), and inflammatory bowel disease (IBD). However, our previous research firstly revealed that melatonin might inhibit pathogenic responses of peripheral Th17 and double-negative (DN) T cells in pSS. More importantly, melatonin administration alleviated the development of pSS in animal models with reduced infiltrating lymphocytes, improved functional activity of salivary gland, and decreased production of inflammatory factors as well as autoantibodies. Owing to the important biological properties reported in melatonin are characteristics closely related to the treatment of pSS; the potential role and underlying mechanisms of melatonin in the administration of pSS are certainly worth further investigations. Consequently, the aim of this review is to give a deep insight to the therapeutic potency of melatonin for pSS.

Melatonin: A Potential Candidate for the Treatment of Experimental and Clinical Perinatal Asphyxia

Perinatal asphyxia is considered to be one of the major causes of brain neurodegeneration in full-term newborns. The worst consequence of perinatal asphyxia is neurodegenerative brain damage, also known as hypoxic-ischemic encephalopathy. Hypoxic-ischemic encephalopathy is the leading cause of mortality in term newborns. To date, due to the complex mechanisms of brain damage, no effective or causal treatment has been developed that would ensure complete neuroprotection. Although hypothermia is the standard of care for hypoxic-ischemic encephalopathy, it does not affect all changes associated with encephalopathy. Therefore, there is a need to develop effective treatment strategies, namely research into new agents and therapies. In recent years, it has been pointed out that natural compounds with neuroprotective properties, such as melatonin, can be used in the treatment of hypoxic-ischemic encephalopathy. This natural substance with anti-inflammatory, antioxidant, anti-apoptotic and neurofunctional properties has been shown to have pleiotropic prophylactic or therapeutic effects, mainly against experimental brain neurodegeneration in hypoxic-ischemic neonates. Melatonin is a natural neuroprotective hormone, which makes it promising for the treatment of neurodegeneration after asphyxia. It is supposed that melatonin alone or in combination with hypothermia may improve neurological outcomes in infants with hypoxic-ischemic encephalopathy. Melatonin has been shown to be effective in the last 20 years of research, mainly in animals with perinatal asphyxia but, so far, no clinical trials have been performed on a sufficient number of newborns. In this review, we summarize the advantages and limitations of melatonin research in the treatment of experimental and clinical perinatal asphyxia.

Melatonin alleviates diet-induced steatohepatitis by targeting multiple cell types in the liver to suppress inflammation and fibrosis

The pathogenesis of nonalcoholic steatohepatitis (NASH), a severe stage of nonalcoholic fatty liver disease, is complex and implicates multiple cell interactions. However, therapies for NASH that target multiple cell interactions are still lacking. Melatonin (MEL) alleviates NASH with mechanisms not yet fully understood. Thus, we herein investigate the effects of MEL on key cell types involved in NASH, including hepatocytes, macrophages, and stellate cells. In a mouse NASH model with feeding of a methionine and choline-deficient (MCD) diet, MEL administration suppressed lipid accumulation and peroxidation, improved insulin sensitivity, and attenuated inflammation and fibrogenesis in the liver. Specifically, MEL reduced proinflammatory cytokine expression and inflammatory signal activation and attenuated CD11C+CD206- M1-like macrophage polarization in the liver of NASH mice. The reduction of proinflammatory response by MEL was also observed in the lipopolysaccharide-stimulated Raw264.7 cells. Additionally, MEL increased liver fatty acid β-oxidation, leading to reduced lipid accumulation, and restored the oleate-loaded primary hepatocytes. Finally, MEL attenuated hepatic stellate cell (HSC) activation and fibrogenesis in the liver of MCD-fed mice and in LX-2 human HSCs. In conclusion, MEL acts on multiple cell types in the liver to mitigate NASH-associated phenotypes, supporting MEL or its analog as potential treatment for NASH.

Erectile Dysfunction: Pharmacological Pathways with Understudied Potentials

Erectile dysfunction (ED) is a public health concern worldwide. In the past, it was perceived as a phenomenon attributed to age advancement. However, more individuals are affected every year that do not fall under that age criterion. Epidemiological research revealed that this abnormality has an association with endothelial dysfunction connected to several cardiovascular (CV) risk factors. Currently, ED is interpreted as a clinical marker for future adverse events and not only as a present health issue that negatively affects the quality of life. The management of ED involves lifestyle modifications, therapeutic optimization for comorbid conditions, and pharmacological and psychosexual therapy. Phosphodiesterase type 5 (PDE5) inhibitors are the first-line pharmacological agents to be prescribed for such a condition. Nonetheless, other pharmacological pathways and agents remain underinvestigated or were investigated at some stage. This review aimed to present to future researchers interested in this field with some pharmacological agents that showed favorable effects on a limited number of studies on human subjects or experimental models.

Influence of climatic conditions in the mesothermal climate area on pregnancies following elective fresh single blastocyst transfer

PURPOSE

To investigate the effect of climatic parameters in the mesothermal climate area on clinical pregnancy and live birth following fresh single blastocyst transfer.

METHODS

This study investigated clinical pregnancies and live births that resulted from 555 ovarian stimulation cycles followed by fresh single blastocyst transfer. The samples were stratified according to climatic conditions (low T, temperature < 12.9 °C; middle T, 12.9 °C ≤ temperature < 22.6 °C; high T, temperature ≥ 22.6 °C; low H, relative humidity < 62.1%; middle H, 62.1% ≤ relative humidity < 66.5%; high H, relative humidity ≥ 66.5%; short S, sunlight duration < 5.2 h; middle S, 5.2 h ≤ sunlight duration < 6.7 h; long S, sunlight duration ≥ 6.7 h). Clinical pregnancy and live birth rates among three groups from each climatic parameter were compared. Multivariable analyses were performed to investigate the effects of climatic conditions on blastocyst development, endometrial thickness, clinical pregnancy, and live birth.

RESULTS

A statistically significant difference was found in pregnancy rates among low T (48.8%), middle T (37.3%), and high T (36.6%) groups. Multivariable analyses revealed that temperature was associated with clinical pregnancy and live birth rates with adjustment for patient age, BMI, type of ovarian stimulation, endometrial thickness, and expansion grade of the transferred blastocyst. The association between climatic parameters and blastocyst development and endometrial thickness was not confirmed.

CONCLUSIONS

This study suggests that lower temperatures in the mesothermal climate area could favorably affect the rates of clinical pregnancy and live birth achieved by fresh single blastocyst transfer.

Novel Therapeutics for Treating Sleep Disorders: New Perspectives on Maydis stigma

Sleep is a restorative period that plays a crucial role in the physiological functioning of the body, including that of the immune system, memory processing, and cognition. Sleep disturbances can be caused by various physical, mental, and social problems. Recently, there has been growing interest in sleep. Maydis stigma (MS, corn silk) is a female maize flower that is traditionally used as a medicinal plant to treat many diseases, including hypertension, edema, and diabetes. It is also used as a functional food in tea and other supplements. β-Sitosterol (BS) is a phytosterol and a natural micronutrient in higher plants, and it has a similar structure to cholesterol. It is a major component of MS and has anti-inflammatory, antidepressive, and sedative effects. However, the potential effects of MS on sleep regulation remain unclear. Here, we investigated the effects of MS on sleep in mice. The effects of MS on sleep induction were determined using pentobarbital-induced sleep and caffeine-induced sleep disruption mouse models. MS extracts decreased sleep latency and increased sleep duration in both the pentobarbital-induced sleep induction and caffeine-induced sleep disruption models compared to the positive control, valerian root extract. The butanol fraction of MS extracts decreased sleep latency time and increased sleep duration. In addition, β-sitosterol enhances sleep latency and sleep duration. Both MS extract and β-sitosterol increased alpha activity in the EEG analysis. We measured the mRNA expression of melatonin receptors 1 and 2 (MT1/2) using qRT-PCR. The mRNA expression of melatonin receptors 1 and 2 was increased by MS extract and β-sitosterol treatment in rat primary cultured neurons and the brain. In addition, MS extract increased the expression of clock genes including per1/2, cry1/2, and Bmal1 in the brain. MS extract and β-sitosterol increased the phosphorylation of ERK1/2 and αCaMKII. Our results demonstrate for the first time that MS has a sleep-promoting effect via melatonin receptor expression, which may provide new scientific evidence for its use as a potential therapeutic agent for the treatment and prevention of sleep disturbance.

The Influence of Circadian Rhythm on the Activity of Oxidative Stress Enzymes

The circadian system synchronizes daily with the day-night cycle of our environment. Disruption of this rhythm impacts the emergence and development of many diseases caused, for example, by the overproduction of free radicals, leading to oxidative damage of cellular components. The goal of this study was to determine the activity of superoxide dismutase (SOD), glutathione peroxidase (GPx), catalase (CAT), glutathione transferase (GST), glutathione reductase (R-GSSG), and the concentration of glutathione (GSH) in the circadian rhythm. The study group comprised 66 healthy volunteers (20-50 years; 33 women; 33 men). The blood was collected at 2, 8 a.m., and 2, 8 p.m. All samples marked the serum melatonin concentration to confirm the correct sleeping rhythm and wakefulness throughout the day. The activity of study enzymes and the concentration of GSH were measured by the spectrophotometric method. Confirmed the existence of circadian regulation of oxidative stress enzymes except for GST activity. The peak of activity of study enzymes and GSH concentration was observed at 2 a.m. The increased activity of enzymes and the increase in GSH concentration observed at night indicate that during sleep, processes allowing to maintain of the redox balance are intensified, thus limiting the formation of oxidative stress.

Exogenous Melatonin Regulates Puberty and the Hypothalamic GnRH-GnIH System in Female Mice

In recent years, the age of children entering puberty is getting lower and the incidence of central precocious puberty is increasing. It is known that melatonin plays an increasingly important role in regulating animal reproduction, but the specific role and mechanism of melatonin in regulating the initiation of puberty remain unclear. The purpose of the current study was to investigate the effect of subcutaneous melatonin injection on pubertal development in female mice and its mechanism of action. Female mice that were 22 days old received 1 mg/kg doses of melatonin subcutaneously every day for 10, 15 and 20 days. The vaginal opening was checked daily. Hematoxylin and eosin (HE) stain was used to determine the growth of the uterus and ovaries. Enzyme-linked immunosorbent assay (ELISA) was used to determine the levels of follicle-stimulating hormone (FSH), gonadotropin-inhibiting hormone (GnIH), and gonadotropin-releasing hormone (GnRH) in serum. By using RT-PCR and Western blotting, the mRNA and protein expression of the hypothalamus GnRH, GnIH, Kisspeptin (Kp), Proopiomelanocortin (POMC), Neuropeptide Y (NPY), as well as G protein-coupled receptor 147 (GPR147) were identified. The findings demonstrated that melatonin could suppress ovarian follicle and uterine wall growth as well as delay vaginal opening, decrease serum levels of GnRH and FSH and increase levels of GnIH. Melatonin increased GnIH and GPR147 expression in the hypothalamus in comparison to the saline group, while decreasing the expression of GnRH, Kisspeptin, POMC, and NPY. In conclusion, exogenous melatonin can inhibit the onset of puberty in female mice by modulating the expression of hypothalamic GnRH, GnIH, Kisspeptin, POMC and NPY neurons and suppressing the hypothalamic–pituitary–gonadal axis.

Intestinal microbiota and melatonin in the treatment of secondary injury and complications after spinal cord injury

Spinal cord injury (SCI) is a central nervous system (CNS) disease that can cause sensory and motor impairment below the level of injury. Currently, the treatment scheme for SCI mainly focuses on secondary injury and complications. Recent studies have shown that SCI leads to an imbalance of intestinal microbiota and the imbalance is also associated with complications after SCI, possibly through the microbial-brain-gut axis. Melatonin is secreted in many parts of the body including pineal gland and gut, effectively protecting the spinal cord from secondary damage. The secretion of melatonin is affected by circadian rhythms, known as the dark light cycle, and SCI would also cause dysregulation of melatonin secretion. In addition, melatonin is closely related to the intestinal microbiota, which protects the barrier function of the gut through its antioxidant and anti-inflammatory effects, and increases the abundance of intestinal microbiota by influencing the metabolism of the intestinal microbiota. Furthermore, the intestinal microbiota can influence melatonin formation by regulating tryptophan and serotonin metabolism. This paper summarizes and reviews the knowledge on the relationship among intestinal microbiota, melatonin, and SCI in recent years, to provide new theories and ideas for clinical research related to SCI treatment.

Pyroptosis and Intervertebral Disc Degeneration: Mechanistic Insights and Therapeutic Implications

Low back pain (LBP) is a common problem worldwide, resulting in great patient suffering and great challenges for the social health system. Intervertebral disc (IVD) degeneration (IVDD) is widely acknowledged as one of the key causes of LBP. Accumulating evidence suggests that aberrant pyroptosis of IVD cells is involved in the pathogenesis of IVDD progression, however, the comprehensive roles of pyroptosis in IVDD have not been fully established, leaving attempts to treat IVDD with anti-pyroptosis approaches questionable. In this review, we summarize the characteristics of pyroptosis and emphasize the effects of IVD cell pyroptosis on the pathological progression of IVDD, including secretion of cytokines, nucleus pulposus cell apoptosis and autophagy, accelerated extracellular matrix degradation, annulus fibrosus rupture, cartilage endplate calcification, vascularization, sensory and sympathetic fiber neoinnervation, and infiltrating lymphatic vessels. Finally, we discuss several interventions used to treat IVDD by targeting pyroptosis. This review provides novel insights into the crucial role of IVD cell pyroptosis in IVDD pathogenesis, and could be informative for developing novel therapeutic approaches for IVDD and LBP.

Efficacy of auricular plaster therapy for sleep disorders in preschool children with autism spectrum disorders: Study protocol for a randomized controlled trial

Background

Children with autism spectrum disorders (ASDs) suffer from sleep disorders to a considerable degree; however, there is no safe and effective treatment available in clinical practice. The objective of the trial is to assess the clinical effectiveness of auricular plaster therapy (APT) in treating sleep disorders in children with ASD.

Method

This is a single-center, patient-assessor blind, randomized controlled trial. A total of 44 preschool children with sleep disorders with ASD will be included in this study. Eligible participants will be randomly assigned to either the auricular plaster group or the sham auricular plaster group in a 1:1 ratio. Participants in the different groups will receive APT or sham APT, respectively, for a total of 30 sessions over 30 days. The primary outcome includes the Children's Sleep Habits Questionnaire (CSHQ), while secondary outcomes include the Autism Behavior Checklist (ABC) and polysomnography (PSG) for total sleep time, sleep latency, awakening duration, and sleep structures. The CSHQ and ABC will be assessed at baseline, 10, 20, 30, 60, 90, and 120 days after randomization, whereas PSG will be assessed at baseline and 30 days after randomization. The follow-up period will be scheduled to be 60, 90, and 120 days after randomization.

Discussion

The results of this study may provide evidence of the efficacy of APT, as well as offer new alternatives for the treatment of sleep disorders in children with ASD.

Trial registration

CHiCTR.org.cn (ChiCTR2100048257). Registered on July 5, 2021.

Associations between treatment with melatonin and suicidal behavior: a nationwide cohort study

STUDY OBJECTIVES

Melatonin is often prescribed to patients with sleep disorders who are known to have elevated suicide risks, yet melatonin's association with suicidal behavior remains to be examined. We investigated whether individuals prescribed melatonin had higher rates of suicide and suicide attempts when compared to individuals who were not prescribed this drug, including both those with and without known mental disorders.

METHODS

A cohort design was applied to longitudinal, register data on all persons aged ≥ 10 years in Denmark during 2007-2016. Based on data from the National Prescription Registry, periods of being in treatment with melatonin were defined using information on the number of tablets and the daily defined dose. We calculated incidence rate ratios for suicide and suicide attempts, as identified in register records, comparing those in treatment with melatonin to those not in treatment.

RESULTS

Among 5,798,923 individuals, 10,577 (0.2%) were treated with melatonin (mean treatment length, 50 days) during the study period. Of those, 22 died by suicide and 134 had at least 1 suicide attempt. People in treatment with melatonin had a 4-fold higher rate of suicide (incidence rate ratio, 4.8; 95% CI, 3.0-7.5) and a 5-fold higher rate of suicide attempt (incidence rate ratio, 5.9; 95% CI, 4.4-8.0) than those not in treatment and when adjusting for sex and age group.

CONCLUSIONS

Treatment with melatonin was associated with suicide and suicide attempt. Although there are several possible explanations, attention to suicide risk is particularly warranted for people with mental comorbidity who are in treatment with melatonin.

CITATION

Høier NK, Madsen T, Spira AP, et al. Associations between treatment with melatonin and suicidal behavior: a nationwide cohort study. J Clin Sleep Med. 2022;18(10):2451-2458.

Sleep disruption and delirium in critically ill children: Study protocol feasibility

Delirium is a serious complication of pediatric critical illness. Sleep disruption is frequently observed in children with delirium, and circadian rhythm dysregulation is one proposed cause of delirium. Children admitted to the pediatric intensive care unit (PICU) experience multiple environmental exposures with the potential to disrupt sleep. Although researchers have measured PICU light and sound exposure, sleep, and delirium, these variables have not yet been fully explored in a single study. Furthermore, caregiving patterns have not often been included as a component of the PICU environment. Measuring the light and sound exposure, caregiving patterns, and sleep of critically ill children requires continuous PICU bedside data collection. This presents multiple methodological challenges. In this paper, we describe the protocol for an observational pilot study of the PICU environment, sleep, and delirium experienced by a sample of 10 critically ill children 1-4 years of age. We also evaluate and discuss the feasibility (i.e., acceptability, implementation, practicality) of the study protocol. Light and sound exposure were measured with bedside sensors. Caregiving was quantified through video recording. Sleep was measured via actigraphy and confirmed by video recording. Delirium screening with the Cornell Assessment of Pediatric Delirium was conducted twice daily, either in person or via video review. This study provides a refined measurement framework to inform future, large-scale studies and the development of nurse-driven sleep promotion interventions.

Melatonin ultrastructural localization in mitochondria of human salivary glands

The hormone melatonin was initially believed to be synthesized exclusively by the pineal gland and the enterochromaffin cells, but nowadays its production and distribution were observed in several other tissues and organs. Among others, the ultrastructural localization of melatonin and its receptors has been reported in human salivary glands. In these glands, the fine localization of melatonin in intracellular organelles, above all in mitochondria, remains to be explored comprehensively. Bioptic samples of parotid and submandibular glands were treated to search for melatonin using the immunogold staining method by transmission electron microscopy. Morphometric analysis was applied to micrographs. The results indicated that, both in parotid and submandibular glands mitochondria, a certain melatonin positivity was present. Within glandular cells, melatonin was less retrieved in mitochondria than in secretory granules; however, its presence in this organelle was clearly evident. Inside striated duct cells, melatonin staining in mitochondria was more prominent than in glandular cells. Our data provide an ultrastructural report on the presence of melatonin in mitochondria of human major salivary glands and represent a fundamental prerequisite for a better understanding of the melatonin role in this organelle.

Melatonin improves mitochondrial function by preventing mitochondrial fission in cadmium-induced rat proximal tubular cell injury via SIRT1-PGC-1α pathway activation

Melatonin is an indoleamine produced in the pineal gland and has many physiological roles. There is increasing evidence that melatonin ameliorates cadmium (Cd)-induced nephrotoxicity. The potential protective impact of melatonin against Cd-induced nephrotoxicity and the mechanisms behind this protection are unknown. The relevance of mitochondrial dynamics in Cd-induced nephrotoxicity and the putative mechanism of melatonin-mediated protection were examined in this study. We show that melatonin prevents Cd-induced nephrotoxicity by inhibiting dynamin-related protein 1 (Drp1)- and mitochondrial fission protein 1 (Fis1)-mediated mitochondrial fission. Melatonin treatment attenuated cytotoxicity, suppressed oxidative stress, restored mitochondrial membrane potential, and increased mitochondrial mass in response to Cd exposure. Consistent with this finding, melatonin treatment increased Cd-inhibited sirtuin 1 (SIRT1) and peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PGC-1α) expression and inhibited Drp1- and Fis1-mediated mitochondrial fission. Like melatonin, SIRT1 overexpression via resveratrol attenuated Drp1- and Fis1-mediated mitochondrial fission and other Cd-induced mitochondrial oxidative injuries effectively. Melatonin has significant pharmacological potential for protecting against Cd-induced nephrotoxicity by preventing excessive mitochondrial fission.

Insufficient reporting of experimental variables as a cause for nonreproducibility in animal physiology? A case study

Nonreproducibility in scientific investigations has been explained by inadequately reporting methodology, honest error, and even misconduct. We hypothesized that, within the field of animal physiology, the most parsimonious explanation for nonreproducibility is inadequate reporting of key methodological details. We further hypothesized that implementation of relatively recently released reporting guidelines has positively impacted journal article quality, as measured by completeness of the methodology descriptions. We analyzed 84 research articles published in five primarily organismal animal physiology journals in 2008-2010 (generally before current guidelines) and 2018-2020. Compliance for reporting 34 variables referring to biology, experiments, and data collection was assessed. Reporting compliance was just ∼61% in 2008-2010, rising only slightly to 67.5% for 2018-2020. Only 21% of the reported variables showed significant differences across the period from 2008-2020. We conclude that, despite attempts by societies and journals to promote greater reporting compliance, such efforts have so far been relatively unsuccessful in the field of animal physiology.

Effects of melatonin on intestinal function and bacterial compositions in sucking piglets

Melatonin has been reported to affect intestinal function by targeting microbiome, morphological structure, barrier integrity and nutrient absorptive system. While the effect of melatonin on intestinal development in newborn infants is obscure, thus, this study firstly attempted to investigate the hypothesis that melatonin treatment improves intestinal development in sucking piglets. 14 healthy newborn piglets received 10 ml melatonin solution (1 mg/ml) or drinking water (n = 7) for 21 days. The results showed that oral administration of melatonin increased liver relative weight (p < 0.05) but failed to affect growth performance in sucking piglets (p > 0.05). Immunostaining jejunal samples from melatonin group showed high expressions of nnos and claudin1, indicating that melatonin improved intestinal neural development and barrier integrity. Also, melatonin promoted intestinal absorptive function evidenced by the increased serum proline concentration in melatonin-treated piglets compared with the control (p < 0.05). Gut microbiota compositions were tested by 16S rDNA sequencing and the results showed that melatonin increased the relative abundance of Actinobacteria compared with the control (p < 0.05) at the phylum level. However, Selenomonadales was markedly reduced compared with the control at the order level (p < 0.05). Gut and faecal volatile fatty acids were tested to evaluate the microbiota metabolism, but no difference was noticed in volatile fatty acid concentrations (p > 0.05). Melatonin improved intestinal development by affecting neural development, barrier integrity, nutrient absorption and microbiota in sucking piglets.

Melatonin Alters the miRNA Transcriptome of Inflammasome Activation in Murine Microglial Cells

Systemic inflammation can have devastating effects on the central nervous system via its resident immune cells, the microglia. One of the primary mediators of this inflammation is inflammasomes, multiprotein complexes that trigger a release of inflammatory proteins when activated. Melatonin, a hormone with anti-inflammatory effects, is an attractive candidate for suppressing such inflammation. In this study, we have investigated how melatonin alters the microRNA (miRNA) transcriptome of microglial cells. For that purpose, we have performed RNA sequencing on a lipopolysaccharide and adenosine triphosphate (LPS + ATP) induced NLR family pyrin domain containing 3 (NLRP3) inflammasome activation model in the N9 mouse microglial cell line, with and without melatonin pre-treatment. We have identified 136 differentially expressed miRNAs in cells exposed to LPS + ATP compared to controls and 10 differentially expressed miRNAs in melatonin pre-treated cells compared to the inflammasome group. We have identified miR-155-3p as a miRNA that is upregulated with inflammasome activation and downregulated with melatonin treatment. We further confirmed this pattern of miR-155-3p expression in the brains of mice injected intraperitoneally with LPS. Moreover, an overexpression study with miRNA-155-3p mimic supported the idea that the protective effects of melatonin in NLRP3 inflammasome activation are partly associated with miRNA-155-3p inhibition.

Review of Drug Therapy for Peripheral Facial Nerve Regeneration That Can Be Used in Actual Clinical Practice

Although facial nerve palsy is not a life-threatening disease, facial asymmetry affects interpersonal relationships, causes psychological stress, and devastates human life. The treatment and rehabilitation of facial paralysis has many socio-economic costs. Therefore, in cases of facial paralysis, it is necessary to identify the cause and provide the best treatment. However, until now, complete recovery has been difficult regardless of the treatment used in cases of complete paralysis of unknown cause and cutting injury of the facial nerve due to disease or accident. Therefore, this article aims to contribute to the future treatment of facial paralysis by reviewing studies on drugs that aid in nerve regeneration after peripheral nerve damage.

The effects and molecular mechanism of heat stress on spermatogenesis and the mitigation measures

Under normal conditions, to achieve optimal spermatogenesis, the temperature of the testes should be 2-6 °C lower than body temperature. Cryptorchidism is one of the common pathogenic factors of male infertility. The increase of testicular temperature in male cryptorchidism patients leads to the disorder of body regulation and balance, induces the oxidative stress response of germ cells, destroys the integrity of sperm DNA, yields morphologically abnormal sperm, and leads to excessive apoptosis of germ cells. These physiological changes in the body can reduce sperm fertility and lead to male infertility. This paper describes the factors causing testicular heat stress, including lifestyle and behavioral factors, occupational and environmental factors (external factors), and clinical factors caused by pathological conditions (internal factors). Studies have shown that wearing tight pants or an inappropriate posture when sitting for a long time in daily life, and an increase in ambient temperature caused by different seasons or in different areas, can cause an increase in testicular temperature, induces testicular oxidative stress response, and reduce male fertility. The occurrence of cryptorchidism causes pathological changes within the testis and sperm, such as increased germ cell apoptosis, DNA damage in sperm cells, changes in gene expression, increase in chromosome aneuploidy, and changes in Na⁺/K⁺-ATPase activity, etc. At the end of the article, we list some substances that can relieve oxidative stress in tissues, such as trigonelline, melatonin, R. apetalus, and angelica powder. These substances can protect testicular tissue and relieve the damage caused by excessive oxidative stress.

Melatonergic Receptors (Mt1/Mt2) as a Potential Additional Target of Novel Drugs for Depression

A complex pathogenesis involving several physiological systems is theorized to underline the development of depressive disorders. Depression is accompanied by circadian regulation disruption and interaction with the functioning of both central and peripheral oscillators. Many aspects of melatonin function unite these systems. The use of drugs for circadian rhythm disorders could inspire a potential treatment strategy for depression. Melatonin plays an essential role in the regulation of circadian rhythms. It exerts effect by activating two types of melatonin receptors, type 1A (MT1) and 1B (MT2). These are G-protein-coupled receptors, predominantly located in the central nervous system. MT1/MT2 agonists could be a useful treatment approach according to all three prevalent theories of the pathogenesis of depression involving either monoamines, synaptic remodeling, or immune/inflammatory events. MT1/MT2 receptors can be a potential target for novel antidepressants with impact on concentrations of neurotrophins or neurotransmitters, and reducing levels of pro-inflammatory cytokines. There is an interesting cross-talk mediated via the physical association of melatonin and serotonin receptors into functional heteromers. The antidepressive and neurogenetic effects of MT1/MT2 agonists can also be caused by the inhibition of the acid sphingomyelinase, leading to reduced ceramide, or increasing monoamine oxidase A levels in the hippocampus. Compounds targeting MT1 and MT2 receptors could have potential for new anti-depressants that may improve the quality of therapeutic interventions in treating depression and relieving symptoms. In particular, a combined effect on MT1 and/or MT2 receptors and neurotransmitter systems may be useful, since the normalization of the circadian rhythm through the melatonergic system will probably contribute to improved treatment. In this review, we discuss melatonergic receptors as a potential additional target for novel drugs for depression.

Melatonin and multiple sclerosis: antioxidant, anti-inflammatory and immunomodulator mechanism of action

BACKGROUND

Melatonin is an indole hormone secreted primarily by the pineal gland that showing anti-oxidant, anti-inflammatory and anti-apoptotic capacity. It can play an important role in the pathophysiological mechanisms of various diseases. In this regard, different studies have shown that there is a relationship between Melatonin and Multiple Sclerosis (MS). MS is a chronic immune-mediated disease of the Central Nervous System.

AIM

The objective of this review was to evaluate the mechanisms of action of melatonin on oxidative stress, inflammation and intestinal dysbiosis caused by MS, as well as its interaction with different hormones and factors that can influence the pathophysiology of the disease.

RESULTS

Melatonin causes a significant increase in the levels of catalase, superoxide dismutase, glutathione peroxidase, glutathione and can counteract and inhibit the effects of the NLRP3 inflammasome, which would also be beneficial during SARS-CoV-2 infection. In addition, melatonin increases antimicrobial peptides, especially Reg3β, which could be useful in controlling the microbiota.

CONCLUSION

Melatonin could exert a beneficial effect in people suffering from MS, running as a promising candidate for the treatment of this disease. However, more research in human is needed to help understand the possible interaction between melatonin and certain sex hormones, such as estrogens, to know the potential therapeutic efficacy in both men and women.

Adding Insult to Injury: Sleep Deficiency in Hospitalized Patients

Sleep deficiency is a common problem in the hospital setting. Contributing factors include preexisting medical conditions, illness severity, the hospital environment, and treatment-related effects. Hospitalized patients are particularly vulnerable to the negative health effects of sleep deficiency that impact multiple organ systems. Objective sleep measurement is difficult to achieve in the hospital setting, posing a barrier to linking improvements in hospital outcomes with sleep promotion protocols. Key next steps in hospital sleep promotion include improvement in sleep measurement techniques and harmonization of study protocols and outcomes to strengthen existing evidence and facilitate data interpretation across studies.

Elevated testicular apoptosis is associated with elevated sphingosine driven by gut microbiota in prediabetic sheep

BACKGROUND

Men with prediabetes often exhibit concomitant low-quality sperm production or even infertility, problems which urgently require improved therapeutic options. In this study, we have established a sheep model of diet-induced prediabetes that is associated with spermatogenic defects and have explored the possible underlying metabolic causes.

RESULTS

We compared male sheep fed a normal diet with those in which prediabetes was induced by a rich diet and with a third group in which the rich diet was supplemented by melatonin. Only the rich diet group had symptoms of prediabetes, and in these sheep, we found impaired spermatogenesis characterized by a block in the development of round spermatids and an increased quantity of testicular apoptotic cells. Comparing the gut microbiomes and intestinal digest metabolomes of the three groups revealed a distinctive difference in the taxonomic composition of the microbiota in prediabetic sheep, and an altered metabolome, whose most significant feature was altered sphingosine metabolism; elevated sphingosine was also found in blood and testes. Administration of melatonin alleviated the symptoms of prediabetes, including those of impaired spermatogenesis, while restoring a more normal microbiota and metabolic levels of sphingosine. Fecal microbiota transplantation from prediabetic sheep induced elevated sphingosine levels and impaired spermatogenesis in recipient mice, indicating a causal role of gut microbiota in these phenotypes.

CONCLUSIONS

Our results point to a key role of sphingosine in the disruption of spermatogenesis in prediabetic sheep and suggest it could be a useful disease marker; furthermore, melatonin represents a potential prebiotic agent for the treatment of male infertility caused by prediabetes.

Controlling the Progression of Curvature in Children and Adolescent Idiopathic Scoliosis Following the Administration of Melatonin, Calcium, and Vitamin D

Idiopathic scoliosis affects a severe number of children. Their quality of life and development are also disturbed. Some therapeutic strategies have been developed to control illness progression and to optimize the quality of life. In this perspective, randomized, case-control, interventional study, the impact of using melatonin, calcium, and vitamin D, respectively, on idiopathic scoliosis patients was analyzed. Our preliminary results showed that these drugs positively affected the illness progression quantified by the spine curvature. Patients with idiopathic scoliosis may benefit from a novel treatment by supplementation with vitamin D, calcium, and melatonin.