Serum Melatonin Levels Research Articles

Gene expression profile associated with Asmt knockout-induced depression-like behaviors and exercise effects in mouse hypothalamus.

Sleep disorder caused by abnormal circadian rhythm is one of the main symptoms and risk factors of depression. As a known hormone regulating circadian rhythms, melatonin (MT) is also namely N-acetyl-5-methoxytryptamine. N-acetylserotonin methyltransferase (Asmt) is the key rate-limiting enzyme of MT synthesis and has been reportedly associated with depression. Although 50–90% of patients with depression have sleep disorders, there are no effective treatment ways in the clinic. Exercise can regulate circadian rhythm and play an important role in depression treatment. In the present study, we showed that Asmt knockout induced depression-like behaviors, which were ameliorated by swimming exercise. Moreover, swimming exercise increased serum levels of MT and 5-hydroxytryptamine (5-HT) in Asmt knockout mice. In addition, the microarray data identified 10 differentially expressed genes (DEGs) in KO mice compared with WT mice and 29 DEGs in KO mice after swimming exercise. Among the DEGs, the direction and magnitude of change in epidermal growth factor receptor pathway substrate 8-like 1 (Eps8l1) and phospholipase C-β 2 (Plcb2) were confirmed by qRT-PCR partly. Subsequent bioinformatic analysis showed that these DEGs were enriched significantly in the p53 signaling pathway, long-term depression and estrogen signaling pathway. In the protein–protein interaction (PPI) networks, membrane palmitoylated protein 1 (Mpp1) and p53-induced death domain protein 1 (Pidd1) were hub genes to participate in the pathological mechanisms of depression and exercise intervention. These findings may provide new targets for the treatment of depression.

Gut microbiota mediate melatonin signalling in association with type 2 diabetes.

It has been shown that melatonin plays a general beneficial role in type 2 diabetes in rodents but its role in humans is controversial. In the present study, we investigated the association between serum melatonin and type 2 diabetes risk in a southern Chinese population in a case-control study. We also examined the role of gut microbiota in this relationship. Individuals with type 2 diabetes (cases) and healthy individuals (controls) (n=2034) were recruited from a cross-sectional study and were matched for age and sex in a case-control study. The levels of serum melatonin were measured and the association between serum melatonin and type 2 diabetes risk was examined using a multivariable logistic regression model. We further conducted a rigorously matched case-control study (n=120) in which gut microbial 16S rRNA was sequenced and metabolites were profiled using an untargeted LC-MS/MS approach. Higher levels of serum melatonin were significantly associated with a lower risk of type 2 diabetes (OR 0.82 [95% CI 0.74, 0.92]) and with lower levels of fasting glucose after adjustment for covariates (β -0.25 [95% CI -0.38, -0.12]). Gut microbiota exhibited alteration in the individuals with type 2 diabetes, in whom lower levels of serum melatonin, lower α- and β-diversity of gut microbiota (p<0.05), greater abundance of Bifidobacterium and lower abundance of Coprococcus (linear discriminant analysis [LDA] >2.0) were found. Seven genera were correlated with melatonin and type 2 diabetes-related traits; among them Bifidobacterium was positively correlated with serum lipopolysaccharide (LPS) and IL-10, whereas Coprococcus was negatively correlated with serum IL-1β, IL-6, IL-10, IL-17, TNF-α and LPS (Benjamini-Hochberg-adjusted p value [false discovery rate (FDR)] <0.05). Moreover, altered metabolites were detected in the participants with type 2 diabetes and there was a significant correlation between tryptophan (Trp) metabolites and the melatonin-correlated genera including Bifidobacterium and Coprococcus (FDR<0.05). Similarly, a significant correlation was found between Trp metabolites and inflammation factors, such as IL-1β, IL-6, IL-10, IL-17, TNF-α and LPS (FDR<0.05). Further, we showed that Trp metabolites may serve as a biomarker to predict type 2 diabetes status (AUC=0.804). A higher level of serum melatonin was associated with a lower risk of type 2 diabetes. Gut microbiota-mediated melatonin signalling was involved in this association; especially, Bifidobacterium- and Coprococcus-mediated Trp metabolites may be involved in the process. These findings uncover the importance of melatonin and melatonin-related bacteria and metabolites as potential therapeutic targets for type 2 diabetes.

Investigating the effect of different light intensities in work environments on Circadian rhythm using animal model

Introduction: light intensity and duration are physical factors that affect hormone secretion and circadian rhythms. This study aimed to determine the effects of various light intensities on serum melatonin and cortisol levels.&#x0D; Materials and methods: This experimental study was carried out on 32 male rats: Group 1 as the control group, received a brightness of 150 lux, and groups 2, 3, and 4 as the exposure groups received light intensities of 300, 5000, and 8000 lux for 14 days, respectively. To evaluate hormone levels, blood samples were taken on before and after 7 and 14 days of exposure. Then cortisol and melatonin levels were determined by ELISA. Data were analyzed using SPSS.&#x0D; Results: The results showed that cortisol levels after seven days of exposure in the groups exposed to the light intensity of 300, 5000, and 8000 lux increased significantly compared to the control group, and after 14 days, the level of cortisol in the groups. Exposure to a light intensity of 5000 and 8000 lux increased significantly compared to the control. Also, melatonin levels in the group of rats exposed to the light intensity of 5000 lux and 8000 lux after 7 and 14 days of exposure compared to the control significantly decreased.&#x0D; Conclusion: Increased light intensity is associated with increased melatonin suppression and cortisol levels. It is suggested that more studies be done to prove the effect of different light intensities on changes in the levels of these hormones at varying hours of the day.&#x0D;

Altered serum levels of melatonin, antioxidant enzymes and oxidative stress in individuals with diabetes mellitus type 2

Altered serum levels of melatonin, antioxidant enzymes and oxidative stress in individuals with diabetes mellitus type 2

Gut Microbiota Mediate Melatonin Signaling in Association With Type 2 Diabetes

ObjectivesTo investigate the association between serum melatonin (MT) and type 2 diabetes (T2D) risk in southern Chinese population in a case-control study as well as the role of gut microbiota in the relationship between them.MethodsT2D cases and healthy controls (n = 2034) were recruited from a cross-sectional study and matched age and sex for a case-control study, and the association between serum MT and T2D risk was examined using a multivariable logistic regression model. We further conducted a rigorously matched case-control study (n = 120), in which gut microbial 16S RNA was sequenced and metabolites were profiled using an untargeted LC-MS/MS approach.ResultsHigher levels of serum MT were significantly associated with a lower risk of T2D (OR = 0.84; 95% CI 0.75–0.93) and with lower levels of fasting glucose after adjustment for covariates (β = −0.21; 95% CI −0.33, −0.09). T2D patients exhibited lower levels of serum MT, lower α- and β-diversity of gut microbiota (p < 0.05), greater abundance of Bifidobacterium and lower abundance of Coprococcus (LDA > 2.0). Seven genera were correlated with MT and T2D related traits, among them Bifidobacterium was positively correlated with serum LPS and IL-10, whereas Coprococcus was negatively correlated with serum IL-1β, IL-6, IL-10, IL-17, INF-α and LPS (FDR < 0.05). Moreover, altered metabolites were detected in the T2D patients, and there was a significant correlation between tryptophan (Trp) metabolites and the melatonin-correlated genera including Bifidobacterium and Coprococcus (FDR < 0.05). A significant correlation also was found between Trp metabolites and inflammation factors, such as IL-1β, IL-6, IL-10, IL-17, INF-α and LPS (FDR < 0.05). Further, we showed that Trp metabolites may serve as a biomarker to predict T2D status (AUC = 0.804).ConclusionsHigher level of serum MT was associated with lower risk of T2D, and that gut microbiota-mediated MT signaling was involved in this association, especially, Bifidobacterium and Coprococcus mediated Trp metabolites may be involved in the process. These findings uncover the importance of MT and MT-related bacteria and metabolites as potential therapeutic targets for T2D.Funding SourcesThis work was supported by the National Natural Science Foundation of China (No.82060593), Natural Science Foundation of Guangxi Province (No. 2018GXNSFDA050019).

The level of melatonin and serotonin neurohormones in blood serum in patients with non-alcoholic fatty liver disease and kidney lesions infected with COVID-19 virus

Background. Research aimed at determining the possible mechanisms of progression in the damage to various organs and systems against the background of COVID-19 infection is an urgent, not thoroughly studied issue in contemporary clinical medicine. The purpose was to determine the peculiarities of changes in serum melatonin (МТ) and serotonin (ST) neurohormone levels in patients with non-alcoholic fatty liver disease (NAFLD) and kidney damage infected with the COVID-19 virus. Materials and methods. 84 patients with NAFLD (steatohepatitis) combined with increased body mass index were examined. NAFLD patients were divided into two groups depending on the presence or absence of type 2 diabetes mellitus (DM), and namely: Group 1 included 34 NAFLD and insulin resistance (IR) patients; Group 2 comprised 38 patients with NAFLD and type 2 DM. All examined patients were tested for MT and ST levels in blood serum. Results. There was a significant decrease in serum MT level in both examined groups— by 2.2 and 3.2 times respectively in group 1 and 2 patients at the time of admission to the hospital. The same trend was identified in the indicators of serum MT level in both groups of patients on day 1 of inpatient treatment (IT)— and namely, its decrease by 1.5 and 2.3 times. Revealed a correlation between the progression of liver damage and the decrease of MT and ST levels in blood serum, which is probably a consequence of its toxic damage against the background of the conducted treatment of patients infected with COVID-19. The decreased serum neurohormone levels also correlate with the insulin level and IR index. There is also a strong correlation between renal damage occurring at the IT stage in NAFLD patients and impaired carbohydrate metabolism during COVID-19 infection and decreased levels of MT and ST in the blood, according to glomerular filtration rate MDRD MDRD (r=0,88; р&lt;0,01 and r=0,94; р&lt;0,01 accordance). Conclusions. COVID-19 infection and its treatment in NAFLD patients with impaired carbohydrate metabolism lead to impaired renal functional status. In patients with NAFLD and carbohydrate metabolism disorders, a decrease in serum levels of the neurohormones MT and ST was found, which progressively decreased against the background of COVID-19 infection and kidney damage in these patients.

Red-light radiation: does it enhance memory by increasing hippocampal LRP-1 and TRPA-1 genes expression?

Purpose Despite the extensive efforts to treat the leading cause of neurodegenerative diseases (ND), a little progress has been reported. Red light might affect ND through many specific mechanisms. The purpose of this investigation is to explore the effect of red light on the expression of low-density lipoprotein receptor-1 (LRP-1) and transient receptor potential ankyrin-1 (TRPA-1) gene in the hippocampus, and the serum melatonin level (SML) of the lipopolysaccharide (LPS)-induced neuro-inflammated rats. Materials and methods Red-light therapy was implemented using a wavelength 630 nm under different light conditions and the passive avoidance (PA) and Y-Maze tests were employed to assess memory performance. To evaluate the LRP-1 and TRPA-1 genes expression, quantitive real-time polymerase chain reaction was performed. To measure the SML, ELISA was performed before and after the red-light radiation. Results LPS caused memory impairment in both behavioral tests. Red-light therapy improved PA memory in all light conditions (p < .001). However, in Y-maze, only the red-light radiation during light and dark cycles, improved memory (p < .01 and p < .001, respectively). In addition, red-light radiation caused significant increase in SML (p < .05). The LRP-1 and TRPA-1 genes expression increased significantly during the dark phase in the red light radiated group compared to non-radiated group (p < .001). Conclusions Taken together, the results suggest that red-light therapy can reduce the complications of memory impairment in rats. This study has found that red-light therapy demonstrates higher effect during the period of dark phase compared to light phase. No doubt, further experimental studies would help us to establish a greater degree of accuracy on this matter.

Biomolecular Assessment and Assay of Kisspeptin, Oxytocin and Melatonin in Female Depressed Patients on Antidepressant Therapy: A Comparative Study

Depression, a common psychiatric disorder with a prevalence of 4.4%, a leading cause of disability and the fourth highest contributor to the global burden of diseases remains underdiagnosed. Biomarkers have been suggested to enable a better understanding of the variable responses to therapy observed in depression. Kisspeptin, oxytocin and melatonin have been implicated in the etiology of anxiety and neuropsychiatric disorders such as seasonal affective depression. This study aimed to compare the differences in the serum levels of oxytocin, melatonin, kisspeptin and their messenger RNAs between antidepressant naïve females (control group) and those who had received at least a four‐week course of antidepressant therapy (test group). The mean serum levels of oxytocin, melatonin and kisspeptin among the test subjects was were 3.18 ±.77 pg/mL, 41.8 ± 2.53 pg/mL, and 291.56 ±106.11 nmol/L, respectively; and 3.14 ±.8.1 pg/mL, 42.06 ±3.18 pg/mL, and 268.89 ± 98.92 nmol/L, respectively for the control group. The total mRNA with the test group was an average of 17.5 ± 18.64), while for the control group it was 11.5 ± 18.41). There were slight correlations between the clinical symptoms of the patients and their mRNA levels but no significant changes in the total mRNA levels of oxytocin and kisspeptin in individuals on antidepressant therapy. There was also no significant relationships in the mRNAs and the serum levels of oxytocin, melatonin and kisspeptin between the test and control groups. Results from this study suggest that kisspeptin, oxytocin and melatonin may not be suitable biomarker for depression but provides a platform for further research.

Melatonin Mediates Osteoblast Proliferation Through the STIM1/ORAI1 Pathway.

Based on the positive correlation between bone mineral density and melatonin levels in blood, this study confirmed that melatonin supplementation prevents postmenopausal osteoporosis. We further confirmed that melatonin promotes an increase in intracellular calcium concentrations through the STIM1/ORAI1 pathway, thereby inducing the proliferation of osteoblasts. Introduction: Osteoporosis (OP) is a progressive, systemic bone disease that is one of the main causes of disability and death in elderly female patients. As an amine hormone produced by the human pineal gland, melatonin plays an important role in regulating bone metabolism. This study intends to investigate the relationship between melatonin levels in human blood and bone density and to suggest the efficacy of melatonin in treating osteoporosis by performing in vivo and in vitro experiments. Methods: We used liquid chromatography-tandem mass spectrometry to determine the serum melatonin levels in postmenopausal women with osteoporosis and young women with a normal bone mass. The bone density, BV/TV, Tb.Th, Tb.Sp and other indicators of postmenopausal osteoporosis and mice with a normal bone mass were detected by measuring bone density and micro-CT. The intracellular calcium ion concentration was detected using fluorescence microscopy and a full-wavelength multifunctional microplate reader, and the expression of SOCE-related genes and STIM1/ORAI1 proteins was detected using PCR and WB. Results: This study confirmed that bone density positively correlates with the melatonin level in human blood. In the animal model, melatonin supplementation reverses postmenopausal osteoporosis. We explored the internal mechanism of melatonin treatment of osteoporosis. Melatonin promotes an increase in intracellular calcium ion concentrations through the STIM1/ORAI1 pathway to induce osteoblast proliferation. Conclusions: This study provides an important theoretical basis for the clinical application of melatonin in patients with osteoporosis and helps to optimize the diagnosis and treatment of postmenopausal osteoporosis.

Melatonin increases bone mass in normal, perimenopausal, and postmenopausal osteoporotic rats via the promotion of osteogenesis

BackgroundOsteoporosis is a disease threatening the health of millions of individuals. Melatonin is found to be a potential anti-osteoporosis drug. However, whether melatonin plays a role against osteoporosis at different stages of the menopause and the underlying mechanisms are unknown.MethodsOvariectomy was utilized as a model of perimenopausal and postmenopausal osteoporosis. A total of 100 mg/kg melatonin, or solvent alone, was added to the drinking water of the rats over 8 weeks. Perimenopausal rats immediately received intervention following ovariectomy while postmenopausal rats received intervention 8 weeks after ovariectomy. All rats underwent overdose anesthesia following intervention after which blood samples and femurs were collected for further analysis. Rat femurs were scanned using micro-CT and examined histologically. The serum levels of melatonin and osteogenic biochemical markers were measured and the expression of osteogenesis-associated genes (Runx2, Sp7) were quantified by real-time quantitative PCR. Alkaline phosphatase (ALP) activity and the gene expression (Col1a1, Runx2, Alpl, and Bglap) were measured after bone marrow mesenchymal stem cells (BMSCs) were osteogenically induced, both with and without melatonin in vitro. ALP staining and Alizarin Red S staining were used to identify osteogenesis.ResultsAnalysis by micro-CT and histological staining demonstrated that bone mass decreased and bone microarchitecture deteriorated over time after ovariectomy. Intervention with melatonin increased bone mass in normal, perimenopausal, and postmenopausal osteoporotic rats. Serum levels of ALP continuously increased after ovariectomy while osteocalcin levels initially rose, then decreased. Melatonin increased the serum levels of ALP and osteocalcin and mRNA expression levels of Runx2 and Sp7 in normal and postmenopausal rats, the opposite of the markers in perimenopausal rats. In vitro study demonstrated that 100 μmol/L melatonin increased the mRNA expression of Col1a1, Runx2, and Alpl three and/or seven days after intervention, and Alpl and Bglap 14 d after intervention. Melatonin increased ALP activity and the extent of ALP and matrix mineralization in the late stage of osteogenesis.ConclusionsBone mass continuously decreased after ovariectomy, while melatonin increased bone mass and ameliorated bone metabolism in normal, perimenopausal, and postmenopausal osteoporotic rats due to the induction of osteogenic differentiation in BMSCs.

Effect of Changes in Photoperiods on Melatonin Expression and Gut Health Parameters in Laying Ducks.

We investigated the effect of photoperiod on ileal morphology, barrier function, short-chain fatty acid (SCFA) contents, microbial flora, melatonin expression, and synthesis in laying ducks. After adaption, a total of 180 Jinding laying ducks (252 days old) were randomly divided into three treatments, receiving 12L (hours of light):12D (hours of darkness), 16L:8D, or 20L:4D. Each treatment had six replicates with 10 birds each. The formal experiment lasted 58 days. Compared with 12L:12D, the significantly higher values of villus height and goblet cell percentage (GCP) were observed in 16L:8D treatment, accompanied with the higher mRNA relative expression of zonula occludens-1, zonula occludens-2, zonula occludens-3, claudin-1, occludin, and mucin 2 (P < 0.05). Besides, significantly higher values of acetate and propionate, butyrate and total SCFA concentrations were simultaneously observed in ileal chyme of 16L:8D treatment (P < 0.05). For the ileal microbial community, the results of principal coordinate analysis (PCoA) visually presented that three photoperiod groups were mainly scattered into three clusters, indicating that the microbiota composition in different photoperiod treatments were quite dissimilar. Lower values of Shannon indicators were observed in the 20L:4D treatment (P < 0.05), meaning that the microbiota α-diversity decreased in the 20-h photoperiod. The relative abundance of Actinobacteria, Fusobacteria, and Proteobacteria at phylum level and Fusobacterium, Clostridium_sensu_stricto_1, and Pectobacterium at genus level kept an appropriate balance in the 16L:8D photoperiod. Melatonin level in serum decreased with the increasing photoperiods at 6:00 and 12:00, which was consistent with melatonin receptor expressions in the hypothalamus and ileal tissue. Meanwhile, the adenosine 3′,5′-cyclic phosphate (cAMP) contents were significantly downregulated in the pineal gland (P < 0.05), in response to the increase in photoperiod. In conclusion, an appropriate photoperiod could improve ileal morphology, barrier function, SCFA profile, and microbial flora, which may be attributed to the appropriate regulation of the circadian rhythm through melatonin as well as its receptor expression, and 16 h could be an adequate photoperiod for laying ducks.

Circadian Disruption of Melatonin among Night Shift Workers and Its Effect on Glycemic Variability

Melatonin is a pineal gland secreted hormone controlling sleep wakefullness. Light is a stimulus and hence this hormone exhibits circadian rhythm. Melatonin has pleiotropic effects on carbohydrate and lipid metabolisms. Glycemic variability is defined as variations in interstitial glucose levels measured every 15 seconds using a sensor-based technique. It is the result of constant carbohydrate metabolism and insulin action. Melatonin also has rhythms that are more akin to a nocturnal hormone. It affects glycemic variability. Variability is associated with a very high cardiac risk factor. Melatonin rhythm may be disrupted in night shift workers as a result of light exposure during the night, with implications for insulin secretion and glycemic variability. Correlation provides greater insight into the rhythmic hormonal activity and altered glucose homeostasis that predispose to diabetes, and thus this study was done to establish the correlation. This study was done to evaluate the effect of melatonin levels on altering glycemic control among night shift workers. This case control study included 40night shift workers both male and female (cases) aged 25-35years and 40 healthy controls of same age group. Blood samples for melatonin estimation were collected at 9PM and 6AM (after night shift work) by venepuncture and serum separated. Serum melatonin levels were estimated by ELISA method. Fasting and post prandial blood glucose were estimated by GOD-POD method and glycemic variability analyzed by Abbott biosensors. Data was analyzed using SPSS package. Night shift workers were found to have decreased melatonin levels and altered blood glucose levels compared to the control group. Melatonin has a negative influence on glycemic variability. This fact was evidenced in our study. Hence this study will help us to understand and intervene.

Clinical research of Pinggan Jiangya decoction combined with penetrating needling at Baihui (GV20) in a period of day from 7 am to 9 am in the treatment of grade 1 and 2 essential hypertension

To explore the clinical effect of Pinggan Jiangya decoction combined with penetrating needling at Baihui (GV20) in a period of day from 7 am to 9 am in the treatment of grade 1 and 2 essential hypertension (EH). A total of 150 cases of grade 1 and 2 EH patients were randomized into an observation group and a control group, 75 cases in each group. In the control group, Pinggan Jiangya decoction was prescribed for oral administration one dose a day, while in the observation group, on the basis of the treatment as the control group, penetrating needling was exerted at GV20 once daily. The treatment duration was 8 weeks. Before and after treatment, the TCM syndrome score, 24 h average systolic blood pressure (24 h ASBP), 24 h average diastolic blood pressure (24 h ADBP), 24 h average pulse pressure difference (24 h PP), morning blood pressure surge (MBPS), 24 h SBP variability (24 h SBPV), 24 h DBP variability (24 h DBPV), serum levels of 5-hydroxytryptamine (5-HT) and melatonin (MT) were compared in the patients of the two groups. The clinical therapeutic effect was observed in the two groups. After the treatment, in the self-comparison of each group, the scores of headache, vertigo, backache, soft knees, tinnitus, 24 h ASBP， 24 h ADBP, 24 h PP, MBPS, 24 h SBPV and 24 h DBPV in the two groups were lower than those before treatment (P<0.01), and the above indexes in the observation group were lower than those in the control group (P<0.01). The level of serum 5-HT after the treatment was lower than that of before the treatment (P<0.01), while the level of MT was higher than that of before the treatment (P<0.01) in both two groups, and the level of 5-HT in the observation group was lower than that of the control group, while the level of MT was higher than that of the control group (P<0.01). The total effective rate of the observation group was 93.3% (70/75), better than 76.0% (57/75) of the control group (P<0.01). Pinggan Jiangya decoction combined with penetrating needling at GV20 in a period of day from 7 am to 9 am can regulate the levels of serum MT and 5-HT, effectively reduce blood pressure, improve blood pressure variability, control morning peak blood pressure, and has a remarkable effect in the treatment of grade 1 and 2 EH.

The Effects of Circadian Rhythm in Adolescents on Optimal Performance in Cognitive Tasks

Introduction: The circadian rhythm is a sleep-wake cycle determined by differences in serum melatonin and cortisol levels, and affects cognition and behaviour. Past research suggests that young adults tend to perform better on cognitive tasks during the afternoon and evening, which may be the optimal time of day in this population. This research protocol seeks to determine whether cognitive performance is affected at times assumed to be optimal for both populations (evening) compared with suboptimal times (morning). Methods: Individuals would be recruited and divided into two groups: adolescents 13–17 and younger adults aged ages 18–25, with all participants of the afternoon/evening chronotype. Saliva is collected directly preceding test-taking. Each group completes a standard computerized test of simple math, logical reasoning, and executive function at both their optimal time of day (TOD) (3:00 to 6:00 PM) and at their non-optimal time of day (8:00 to 11:00 AM). Neuroelectric activity is recorded using electroencephalography (EEG). Results: We hypothesize that adolescents and younger adults will be at their optimal performance level (measured by EEG and behavioural measures) between 3 to 6 P.M. rather than from 8 to 11 AM, due to their circadian rhythm. We expect TOD to influence reaction times and accuracy during task completion. A difference will be seen across many neural indices such as event-related potentials (ERPs) and alpha and theta power demonstrating optimal performance in the evening. Discussion: Higher cortisol levels and changes in amplitude and latency of P3, N2Pc, N450, and PD ERP indices and differences in alpha and theta frequencies may be associated with optimal cognitive performance. This is related to faster response time, focus, and overall higher accuracy. Based on the anticipated results, one could alter the timing of task completion to fit different age groups’ peak mental ability. Conclusion: Continuously working at non-optimal times could lead to chronic circadian rhythm disruption, which could result in the deterioration of physical and mental health. Aspects of everyday life, such as student test-taking times, can be improved to benefit both individuals and institutions by catering to an individual’s optimal TOD.

The Effect of Chronic Intermittent Hypobaric Hypoxia on Sleep Quality and Melatonin Serum Levels in Chilean Miners.

High-altitude mining is an important economic resource for Chile. These workers are exposed to chronic intermittent hypobaric hypoxia (CIHH), which reduces their sleep quality and increases the risk of accidents and long-term illnesses. Melatonin, a hormone produced by the pineal gland, is a sleep inducer that regulates the circadian cycle and may be altered in populations subjected to CIHH. This work aimed to assess the relationship between altitude, sleep quality, and plasma melatonin concentrations in miners with CIHH exposure. 288 volunteers were recruited from five altitudes (0, 1,600, 2,500, 3,500, and 4,500 m). All volunteers worked for 7 days at altitude, followed by 7 days of rest at sea level. We performed anthropometric assessments, nocturnal oximetry, sleep quality and sleepiness surveys, and serum melatonin levels upon awakening. Although oxygen saturation progressively decreased and heart rate increased at higher altitudes, subjective perception of sleep quality was not significantly different, and sleepiness increased in all groups compared to population at sea level. Similarly, melatonin levels increased at all assessed altitudes compared to the population at sea level. These data confirm that sleep disturbances associated with CIHH increase morning melatonin levels. Therefore, this hormone and could potentially serve as a biomarker of sleep quality.

Association between Melatonin Value and Interleukins1B, -18, and -33 Levels in Patients with Different Stages of Non-Alcoholic Fatty Liver Disease.

BACKGROUND: Interaction between immune modulators and inflammatory factors is considered as one of the main underlying pathologies of non-alcoholic fatty liver disease (NAFLD). Hence we aimed to assess the association between these cytokines and melatonin. METHODS: We enrolled adult patients diagnosed with fatty liver by ultrasonography in a crosssectional study. All of them underwent Fibroscan evaluation. The subjects who met the inclusion and exclusion criteria for NAFLD were involved. A normal group who did not have NAFLD, viral or non-viral hepatitis, and without a history of pancreatobiliary surgery, bariatric surgery, and intake of any medication that influence the liver was also selected. The participants were categorized into the three following groups: 1) fibrosis>9.1 kPa and steatosis>290 dbm, 2) fibrosis: 6-9.0 kPa and steatosis 240-290 dbm, and 3) normal group with fibrosis<6.0 kPa and steatosis<240 dbm. Laboratory assessment and a questionnaire including demographic, anthropometric, laboratories, and clinical data were completed for each of them. RESULTS: Totally 97 subjects were enrolled in the present study. The mean age of the subjects was 42.2±11.3 years. 60% of them (59 patients) were female. Serum levels of melatonin, interleukin (IL)-1B, IL-18, and IL-33 increased according to the advancing of NAFLD state. Based on multiple linear regression model, melatonin was significantly associated with IL-1B (β=2.8, P<0.001,95% CI=1.41-4.19), IL-18 (β=0.018, P=0.0005, 95% CI=0.006-0.03), and IL-33 (β=0.31, P=0.045, 95% CI=0.008-0.62) after adjustment for other variables. CONCLUSION: Melatonin level has a strong association with these cytokines. This linkage probably influences on the development and progression of NAFLD. Therefore it can be hypothesized that the therapeutic approach that affects this process may have a significant impact.

Effect of COVID-19 on sleep pattern, mobile usage, and serum melatonin level among 1st-year medical students

Effect of COVID-19 on sleep pattern, mobile usage, and serum melatonin level among 1^st-year medical students

Sıçan Subaraknoid Kanama Modelinde Bilateral Superior Servikal Ganglionektomi ve Melatonin Seviyeleri: Basit Önlemler Melatonin Düzeylerini Koruyabilir

Aim: Subarachnoid hemorrhage (SAH) is a serious disease, and it is thought that melatonin may have positive effects after SAH. Bilateral resection or blockage of superior cervical ganglions has constant effects on melatonin levels. Animal models with bilateral superior cervical ganglionectomy (SCG) show the role of superior cervical ganglion on melatonin and give clues about simple precautions which may help to prevent unfavorable outcomes in SAH patients. The aim of this study is to examine how melatonin levels change in SAH and SCG models. Material and Methods: Forty-two Sprague Dawley male rats weighing 200-250 g were used in the study and randomly divided into six groups. Arterial blood samples were collected 24 hours after the procedure in all groups. Serum melatonin levels of the groups were studied. Results: A significant difference in blood melatonin levels was observed between SAH and SCG groups, and against the control group. There was no significant difference between the melatonin levels in SCG group and SAH+SCG group (p=0.983). The mean blood melatonin level of the SAH group was higher than the SCG (p&amp;lt;0.001), SAH+SCG (p&amp;lt;0.001) and control groups (p=0.001). The mean blood melatonin levels of SAH+SCG and SCG groups were lower than the mean blood melatonin levels of the other groups and also the SAH group (p&amp;lt;0.001). Conclusion: Bilateral SCG significantly inhibited the abrupt increase of serum melatonin levels after SAH model in rats. Future studies aiming to address melatonin’s complex outcomes should take into account that minor exogenous factors may affect serum melatonin levels.

Obstructive sleep apnea syndrome: association of serum melatonin, increased daytime sleepiness, and intermitting night hypoxemia

The relevance of studies related to the features of respiratory disorders during sleep is undeniable due to the steady growth of the worldwide prevalence of apnea syndrome, which leads to a decrease in quality of life, the risk of early cardiovascular diseases together with cerebrovascular, endocrine, and pulmonary disorders.The aim of this study was to determine the relationship between the morning serum melatonin, blood oxygen saturation (SрO2), and increased daytime sleepiness in patients with SOAS, as well as to assess changes in the production of endogenous melatonin after eliminating clinical manifestations of nocturnal hypoxemia, through a 3-month course of non-invasive continuous positive airway pressure (CPAP) therapy. The study enrolled 30 male patients who came to the Federal State Public Scientific Institution “Scientific Centre of Family Health and Human Reproduction Problems” because of snoring, sleep apnea, and increased daytime sleepiness.Methods. Polysomnography, questionnaire, HPLC-MS/MS analysis of serum melatonin levels, CPAP-therapy for the respiratory support at home for 3 months, monitoring of the sleep scores, serum melatonin, and daytime sleepiness after the treatment.Results. A comparative assessment of the sleep scores before and after the respiratory support for 3 months revealed a significant improvement in sleep structure, elimination of the apnea episodes, and restoration of blood SрO2 after the therapy. Analysis of the serum melatonin vales confirmed a statistically significant increase of melatonin level against baseline in patients with SOAS after the treatment. A correlation analysis showed a relationship between the melatonin level, daytime sleepiness, and blood SрO2.Conclusion. The results of this study and the data of other researchers demonstrate that the elimination of intermittent nocturnal hypoxia in patients with SOAS allows reducing the morning serum melatonin level, thereby reducing the daytime sleepiness and subsequently improving the quality of life.

Decreased Circulating Melatonin with Loss of Age-Related Biphasic Change in Patients with Oral Squamous Cell Carcinoma

Background: Melatonin, produced by the pineal gland, is known for its antioxidant, oncostatic, and anti-inflammatory properties. However, studies on serum melatonin levels in different cancer types have yielded conflicting results, and little is known about the clinical significance of serum melatonin in oral squamous cell carcinoma (OSCC) in the Southern Asian population. Therefore, we explored its role in OSCC in this study. Methods: A total of 67 male OSCC patients and 78 healthy controls were enrolled in this case–control study. The serum levels of melatonin were determined by enzyme-linked immunosorbent assay (ELISA) and compared between the two groups. Results: The serum melatonin levels were significantly lower in OSCC patients compared with healthy controls (mean ± standard deviation, 15.0 ± 4.6 vs. 18.5 ± 11.8 pg/mL, p = 0.02). In the subgroup of age less than 55 years (mean age of OSCC), OSCC patients had a significantly decreased melatonin level than healthy controls (mean melatonin, 15.7 ± 12.6 vs. 20.8 ± 3.9 pg/mL, p = 0.02). Decreased serum melatonin (odds ratio (OR): 0.95, 95%CI: 0.91–0.99), alcohol consumption (OR: 29.02, 95%CI: 11.68–72.16), betel quid chewing (OR:136.44, 95%CI: 39.17–475.27), and cigarette smoking (OR:29.48, 95%CI: 11.06–78.60) all increased the risk of OSCC under univariate analyses of logistic regression. Betel quid chewing (OR: 45.98, 95%CI: 10.34–204.49) and cigarette smoking (OR:6.94, 95%CI: 1.60–30.16) were the independent risk factors for OSCC in Taiwan. In addition, a negative correlation between age and melatonin level was observed in healthy controls (Pearson r = −0.24, p = 0.03). However, the negative correlation was lost in patients with OSCC. Melatonin concentration had no association with the severity of OSCC. Conclusion: Overall, our study provides evidence that serum melatonin levels decreased in OSCC patients in Taiwan and the decreased level is much significant in young populations and suggests that the decreased melatonin was associated with OSCC, especially in young populations. Further studies are warranted to investigate whether melatonin can be a useful non-invasive screening tool for OSCC.