Pathophysiology of Depression: Molecular Regulation of Melatonin Homeostasis - Current Status

Participation of Ca2+-Calmodulin-Dependent Protein Kinase II in the Antidepressant-Like Effects of Melatonin

Melatonin (N-acetyl-5-methoxytryptamine) is an indoleamine secreted by the pineal gland during the dark phase of the photoperiod. Its main function is the synchronization of different body rhythms with the dark-light cycle. Research on melatonin has significantly advanced since its discovery and we now know that it has considerable significance in various physiological processes, including immunity, aging, and reproduction. Moreover, in recent years evidence of the pharmacological possibilities of melatonin has increased. Indoleamine, on the other hand, has antidepressant-like effects in rodents, which may be mediated by the activation of calcium-calmodulin-dependent kinase II (CaMKII) and are also related to the regulation of neuroplasticity processes, including neurogenesis, synaptic maintenance, and long-term potentiation. Remarkably, patients with major depression show decreased levels of circulating melatonin in plasma. This review presents evidence of the antidepressant-like effects of melatonin in preclinical models and the participation of CaMKII in these actions. CaMKII's role in cognition and memory processes, which are altered in depressive states, are part of the review, and the effects of melatonin in these processes are also reviewed. Furthermore, participation of CaMKII on structural and synaptic plasticity and the effects of melatonin are also described. Finally, the advantages of using melatonin in combination with other antidepressants such as ketamine for neuroplasticity are described. Evidence supports that CaMKII is activated by melatonin and downstream melatonin receptors and may be the common effector in the synergistic effects of melatonin with other antidepressants. SIGNIFICANCE STATEMENT: This review compiled evidence supporting that melatonin causes antidepressant-like effects in mice through calmodulin kinase II stimulation of downstream melatonin receptors as well as the participation of this enzyme in neuroplasticity, memory, and cognition. Finally, we describe evidence about the effectiveness of antidepressant-like effects of melatonin in combination with ketamine.

Modulation of neural circuits by melatonin in neurodegenerative and neuropsychiatric disorders

Neurodegenerative and neuropsychiatric disorders are two broad categories of neurological disorders characterized by progressive impairments in movement and cognitive functions within the central and peripheral nervous systems, and have emerged as a significant cause of mortality. Oxidative stress, neuroinflammation, and neurotransmitter imbalances are recognized as prominent pathogenic factors contributing to cognitive deficits and neurobehavioral anomalies. Consequently, preventing neurodegenerative and neuropsychiatric diseases has surfaced as a pivotal challenge in contemporary public health. This review explores the investigation of neurodegenerative and neuropsychiatric disorders using both synthetic and natural bioactive compounds. A central focus lies on melatonin, a neuroregulatory hormone secreted by the pineal gland in response to light-dark cycles. Melatonin, an amphiphilic molecule, assumes multifaceted roles, including scavenging free radicals, modulating energy metabolism, and synchronizing circadian rhythms. Noteworthy for its robust antioxidant and antiapoptotic properties, melatonin exhibits diverse neuroprotective effects. The inherent attributes of melatonin position it as a potential key player in the pathophysiology of neurological disorders. Preclinical and clinical studies have demonstrated melatonin's efficacy in alleviating neuropathological symptoms across neurodegenerative and neuropsychiatric conditions (depression, schizophrenia, bipolar disorder, and autism spectrum disorder). The documented neuroprotective prowess of melatonin introduces novel therapeutic avenues for addressing neurodegenerative and psychiatric disorders. This comprehensive review encompasses many of melatonin's applications in treating diverse brain disorders. Despite the strides made, realizing melatonin's full neuroprotective potential necessitates further rigorous clinical investigations. By unravelling the extended neuroprotective benefits of melatonin, future studies promise to deepen our understanding and augment the therapeutic implications against neurological deficits.

Methylation of melatonin receptors in patients with unipolar and bipolar depression

Disturbances of melatonin secretion alter the circadian rhythm and sleep-wake cycle, which is observed among patients with depression. Melatonin acts via melatonin receptors MT1 and MT2, which are present in many tissues, including peripheral blood mononuclear cells (PBMC). We assume that disturbances of the melatonin pathway in the brain may be reflected by molecular changes in peripheral organs. The study objective was to evaluate the methylation profile of CpG island in the promoter region of melatonin receptor genes MTNR1A and MTNR1B in PBMC of patients with depression and compare it with healthy volunteers. The study group comprised 85 patients with unipolar (UP) and bipolar disorders (BP) and 83 controls. The methylation pattern of CpG island in the promoter region was analyzed using the quantitative methylation-specific real-time PCR (qMSP-PCR) method. We found that the methylation profile of the patients with depression varied in comparison to the control group. The methylation level of MTNR1A was significantly lower among depressed patients compared to controls. Additionally, melatonin concentration was negatively correlated with MTNR1B methylation level among the UP patients. The study may suggest that the methylation profile of melatonin receptors in PBMC may be used as a complementary molecular marker in depression diagnosis.

Current Knowledge of the Antidepressant Activity of Chemical Compounds from Crocus sativus L

Psychotropic effect of Crocus sativus L. (family Iridaceae) biologically active chemical compounds are quite well documented and they can therefore be used in addition to the conventional pharmacological treatment of depression. This systematic review on antidepressant compounds in saffron crocus and their mechanisms of action and side effects is based on publications released between 1995−2022 and data indexed in 15 databases under the following search terms: antidepressant effect, central nervous system, Crocus sativus, cognitive impairement, crocin, crocetin, depression, dopamine, dopaminergic and serotonergic systems, picrocrocin, phytotherapy, neurotransmitters, safranal, saffron, serotonin, and biologically active compounds. The comparative analysis of the publications was based on 414 original research papers. The investigated literature indicates the effectiveness and safety of aqueous and alcoholic extracts and biologically active chemical compounds (alkaloids, anthocyanins, carotenoids, flavonoid, phenolic, saponins, and terpenoids) isolated from various organs (corms, leaves, flower petal, and stigmas) in adjuvant treatment of depression and anxiety. Monoamine reuptake inhibition, N-methyl-d-aspartate (NMDA) receptor antagonism, and gamma-aminobutyric acid (GABA)-α agonism are the main proposed mechanism of the antidepressant action. The antidepressant and neuroprotective effect of extract components is associated with their anti-inflammatory and antioxidant activity. The mechanism of their action, interactions with conventional drugs and other herbal preparations and the safety of use are not fully understood; therefore, further detailed research in this field is necessary. The presented results regarding the application of C. sativus in phytotherapy are promising in terms of the use of herbal preparations to support the treatment of depression. This is particularly important given the steady increase in the incidence of this disease worldwide and social effects.

Sleep deprivation leads to further impairment of hippocampal synaptic plasticity by suppressing melatonin secretion in the pineal gland of chronically unpredictable stress rats

There has been ample research showing that insomnia is a potential trigger of depression as well as a symptom of depression. These two factors contribute to behavioral problems and are closely related to the plasticity of hippocampal synapses. Although depression and insomnia impair hippocampal synaptic plasticity, the mechanism by which this happens remains a mystery. This study aimed to investigate the pathogenesis of insomnia comorbidity in depression and the regulatory effect of venlafaxine combined with melatonin on hippocampal synaptic plasticity in chronic unpredictable mild stress (CUMS) with sleep deprivation (SD) rats. Thus, rats were subjected to 14 days of chronic mild unpredictable stress, gradually acclimated to sleep deprivation on days 12-14. Followed by 21 consecutive days of sleep deprivation, 18 hours per day, with daily gavage of venlafaxine (13.5 mg/kg) + melatonin (72 mg/kg) on days 15-36. Venlafaxine + melatonin treatment improves depression-like behavior, pentobarbital sodium experimental sleep latency, and sleep duration in CUMS +SD rats. In addition to improving depressive-like behaviors, sleep deprivation also upregulates the expression of caspase-specific cysteine protein 3 (Caspase 3) in the pineal glial cells of chronic mild rats, as well as in hippocampal microglia. Expression of ionic calcium-binding adaptor 1 (iba-1), downregulates the secretion of several synaptic plasticity-related proteins, notably cAMP response element binding protein (CREB), glial cell line-derived neurotrophic factor (GDNF), and the synaptic scaffolding protein Spinophiline (Spinophiline). Hematoxylin-eosin staining showed that the structure of the pineal gland and hippocampus was damaged, and Golgi staining showed that the dendrites and spines in the DG area of ​​the hippocampus were destroyed, vaguely aggregated or even disappeared, and the connection network could not be established. Western blot analysis further revealed a positive correlation between low melatonin levels and reduced Spinophiline protein. Interestingly, venlafaxine + melatonin reversed these events by promoting hippocampal synaptic plasticity by regulating melatonin secretion from the pineal gland. Therefore, it exerted an antidepressant effect in sleep deprivation combined with CUMS model rats. Overall, the results of this study suggest that the pathophysiology of depressive insomnia comorbidity is mediated by impaired pineal melatonin secretion and impaired hippocampal synaptic plasticity. In addition, these responses are associated with melatonin secretion from the pineal gland.

Pineal morphology of the clinical high-risk state for psychosis and different psychotic disorders

BACKGROUND

Pineal volume reductions have been reported in schizophrenia and clinical high-risk states for the development of psychosis, supporting the role of melatonin dysregulation in the pathophysiology of psychosis. However, it remains unclear whether pineal volume is associated with the later onset of psychosis in individuals at clinical high-risk (CHR) of psychosis or if pineal atrophy is specific to schizophrenia among different psychotic disorders.

METHODS

This magnetic resonance imaging study examined the volume of and cyst prevalence in the pineal gland in 135 individuals at CHR of psychosis [52 (38.5%) subsequently developed psychosis], 162 with first-episode psychosis (FEP), 89 with chronic schizophrenia, and 87 healthy controls. The potential contribution of the pineal morphology to clinical characteristics was also examined in the CHR and FEP groups.

RESULTS

Pineal volumes did not differ significantly between the CHR, FEP, and chronic schizophrenia groups, but were significantly smaller than that in healthy controls. However, pineal volumes were not associated with the later onset of psychosis in the CHR group or FEP sub-diagnosis (i.e., schizophrenia, schizophreniform disorder, affective psychosis, and other psychoses). No significant differences were observed in the prevalence of pineal cysts between the groups, and it also did not correlate with clinical characteristics in the CHR and FEP groups.

CONCLUSION

These results suggest that pineal atrophy is a general vulnerability marker of psychosis, while pineal cysts do not appear to contribute to the pathophysiology of psychosis.

Highly Synergistic Sensor of Graphene Electrode Functionalized with Rutile TiO2 Microstructure to Detect L-Tryptophan Compound

Electrochemical processes are an effective method for detecting dangerous food ingredients. The synergetic between the reduction-oxidation (redox) processes inspired several papers and spurred research towards studying the new materials that can further adapt to optimize the rapid detection of chemical compounds. In this study, we report the eco-synthesis using graphene/TiO₂ rutile (G/TiO₂) electrode microstructures easily prepared through the physical method by mixing graphene and TiO₂ powder and its application for sensing L-tryptophan (Trp) compound. The material characterization results show that the graphene surface is smoother than the G/TiO₂ material. Graphene has been detected using X-ray diffraction (XRD) at a value of 2 thetas 26.39° and TiO₂ forms rutile crystals (110). The FTIR spectrum exhibits the functional groups from graphene of -OH, C-H, C=C, C-O, and TiO₂ identified with Ti-O bonds. The electrochemical test against G/TiO₂ electrode microstructures for Trp compound shows that 0.5 g TiO₂ rutile was the best composition functionalized with graphene material under 0.1M K₃[Fe(CN)₆] + 0.1M NaNO₃ electrolyte with a scan rate of 0.1 V/s. Determination of the detection limit was obtained at 0.005 mg/L with a HorRat value of 1.05%. The stability test was carried out for 25 days, and the addition of Pb(NO₃)₂ as an interference compound had a significant effect on the decrease in electrode performance.

A single intravenous administration of a sub-anesthetic ketamine dose during the perioperative period of cesarean section for preventing postpartum depression: A meta-analysis

The feasibility of intravenous ketamine administration during the perioperative period of cesarean section to prevent postpartum depression (PPD) has not been determined by meta-analysis. To evaluate the efficacy, safety and dose of prophylactic ketamine in offsetting PPD, we retrieved the following databases in English or Chinese from inception to December 2020: Pubmed, Embase, Web of Science, The Cochrane Library, CNKI, VIP and Wanfang. A total of 10 studies (9 RCTs and 1 retrospective study) were included with 2087 cases. Meta-analysis showed that in ketamine group, the score and the prevalence of PPD within 1 week postpartum were significantly reduced, whereas PPD score after 4 weeks postpartum showed no superiority. There was no significant difference in terms of total adverse events rate, although vomiting occurred more frequently in the ketamine group. In addition, we found that ketamine efficacy emerged at 0.5 mg/kg. By meta-regression, we observed that: (1) Age and BMI are negatively associated with mood response to ketamine. (2) An analgesic pump containing ketamine for continuous 48 h postpartum administration was more efficacious than an intravenous injection of ketamine during cesarean section. Current evidence shows ketamine could be efficacious and safe in the prophylactic management of PPD in women having a cesarean section.

The Therapeutic Effect of Exogenous Melatonin on Depressive Symptoms: A Systematic Review and Meta-Analysis

Background

Depression-related mortality and morbidity pose growing public health burdens worldwide. Although the therapeutic effect of exogenous melatonin on depression has been investigated, findings remain inconsistent. We conducted this systematic review and meta-analysis to clarify the effectiveness of melatonin in the treatment of depression, including primary and secondary depression symptoms.

Methods

We searched the online databases of PubMed, EMBASE, and the Cochrane Library for original studies published up to May 2021. We used STATA 14.0 software to synthesize the results of included studies. To evaluate the effectiveness of melatonin, we calculated the standardized mean differences (SMDs) and 95% confidence intervals (CIs) of depression scores between the melatonin and placebo groups.

Results

Our literature search returned 754 publications, among which 19 studies with 1,178 patients (715 women, 463 men; mean age: 56.77 years) met inclusion criteria. Melatonin dosages ranged from 2 to 25 mg per day; treatment durations were between 10 days and 3.5 years. Our synthesized results showed that melatonin was not found significantly beneficial for alleviating depressive symptoms (SMD = -0.17, 95% CI = [-0.38, 0.05]). Subgroup analysis demonstrated that the decrease in depression scores measured with the Beck Depression Inventory (BDI) was significant (SMD = -0.52, 95% CI = [-0.73, -0.31]).

Conclusions

There is very limited evidence for effects of melatonin on depression.

New uses of Melatonin as a Drug, a Review

Melatonin is a simple compound with a proper chemical name N-acetyl-5-methoxy tryptamine and known as a hormone controlling circadian rhythm. Humans produce melatonin at night which is the reason for sleeping in the night and awakening over the day. Melatonin interacts with melatonin receptors MT1 and MT2 but it was also revealed that melatonin is a strong antioxidant and it also has a role in regulation of cell cycle. Currently, melatonin is used as a drug for some types of sleep disorder but the recent research points to the fact that melatonin can also serve for the other purposes including prophylaxis or therapy of lifestyle diseases, cancer, neurodegenerative disorders and exposure to chemicals. This review summarizes basic facts and direction of the current research on melatonin. The actual literature was scrutinized for the purpose of this review.

Reiki for promotion of health and sleep quality in hospital nursing professionals

ABSTRACT Objectives: to know the repercussions of a Reiki therapy intervention on the sleep quality of nursing professionals working in a general hospital. Methods: a qualitative-quantitative study conducted with 16 professionals from the nursing team of a hospital in northwest Paraná, who participated in an intervention consisting of six weekly Reiki sessions. Data collected from September, 2019 to March, 2020 through semi-structured interviews and application of the Pittsburgh Sleep Quality Index before and after the intervention. Results: better sleep quality, characterized by a reduction in the time to fall asleep and in nightmares, and an increase in sleeping hours. Conclusions: reiki intervention had a positive impact on the sleep quality of participants.

Reiki para promoção da saúde e qualidade do sono em profissionais de enfermagem de hospital

RESUMO Objetivos: conhecer as repercussões de intervenção com sessões de reiki na qualidade do sono de profissionais de enfermagem atuantes em um hospital geral. Métodos: estudo de abordagem quali-quantitativa realizado com 16 profissionais da equipe de enfermagem de um hospital no noroeste do Paraná que participaram de uma intervenção constituída por seis sessões semanais de reiki. Dados coletados de setembro/2019 a março/2020, mediante entrevista semiestruturada e aplicação do Índice de Qualidade do Sono de Pittsburgh antes e após o término da intervenção. Resultados: melhora na qualidade do sono, caracterizada por redução do tempo para adormecer e dos pesadelos e aumento nas horas dormidas. Conclusões: a intervenção com reiki repercutiu de forma positiva sobre a qualidade do sono das participantes.

The Association between Melatonin Levels and Sleep Quality in Patients with Pruritus: A Potential Biomarker on a Candidate Future Treatment

Background:

Melatonin is a hormone that regulates the sleep–wake cycle and has immunomodulatory and anti-inflammatory roles.

Aims:

The aim of this study is to assess melatonin levels and investigate the association with pruritus severity, sleep quality, and depressive symptoms in dermatoses with nocturnal pruritus.

Methods:

The study was a prospective study with 82 participants, including 41 patients and 41 healthy volunteers. The visual analog scale (VAS), Pittsburg Sleep Quality Index (PSQI), and Beck Depression Inventory (BDI) were recorded for each patient. To assess the melatonin levels, urinary 6-sulfatoxymelatonin levels in the first urine in the morning were measured.

Results:

Melatonin concentrations were significantly lower (P = 0.007), while the BDI (P = 0.001) and PSQI (P = 0.001) scores were significantly higher in the patients with pruritus than in the healthy control subjects. There was an inverse correlation between melatonin levels and PSQI scores (r = −0.355, P = 0.023), and a positive correlation was detected between BDI scores and PSQI scores (r = 0.631, P = 0.001) in the pruritus group.

Conclusion:

Melatonin levels were found to decrease in relation to sleep quality in nocturnal pruritus patients. Low melatonin levels in these patients may be associated with sleep disorders and pruritus.

Neuroprotective effects of oleuropein: Recent developments and contemporary research

Neurological disorders are increasing at a faster pace due to oxidative stress, protein aggregation, excitotoxicity, and neuroinflammation. It is reported that the Mediterranean diet including olives as a major dietary component prevents and ameliorates neurological anomalies. Oleuropein is the major bioactive component in different parts of the Olive (Olea europaea L.) tree. Several mechanisms have been reported for the neuroprotective role of oleuropein including induction of apoptosis and autophagy, enhancing the antioxidant pool of the cerebral region, decreasing the unnecessary release of proinflammatory cytokines and chemokines by deactivating the microglia cells and astrocytes thus preventing the occurrence of neuroinflammation. Regular intake of oleuropein seems to be correlated with decreased risks of neural disorders including Alzheimer's, Parkinson's, strokes, depression, anxiety, epilepsy, and others. This review majorly discusses the chemistry, biosynthesis, and metabolism of oleuropein along with an updated vision of its neuroprotective role in counteracting the acute and chronic neurodegenerative and neuropsychiatric disorders. Moreover, mechanisms by which oleuropein may prevent neurodegeneration are reviewed. PRACTICAL APPLICATION: Neurological disorders are negatively affecting the health and life quality of individuals around the globe. Although various medicinal solutions are available to tackle such ailments, none has proven to fully cure and being deprived of side effects. In this respect, the prevention of such disorders using natural remedies may be an effective strategy to overcome the incidence of the increasing cases. Furthermore, the natural compounds provide a safer alternative to pharmaceutical drugs. Hence, oleuropein from olive tree products is found to be efficacious against neurological disorders. This review provides an updated insight on the positive effects of oleuropein against neurodegenerative and neuropsychiatric disorders. The diet practitioners and nutraceutical companies may benefit from the provided information to design and develop strategies to improve the mental health of suffering individuals.

Research progress of melatonin (MT) in improving ovarian function: a review of the current status

Melatonin (MT) is an endogenous hormone mainly synthesized by pineal cells, which has strong endogenous effects of eliminating free radicals and resisting oxidative damages. Melatonin (MT) can not only regulate the body’s seasonal and circadian rhythms; but also delay ovarian senescence, regulate ovarian biological rhythm, promote follicles formation, and improve oocyte quality and fertilization rate. This review aimd to provide evidence concerning the synthesis and distribution, ovarian function, and role of MT in development of follicles and oocytes. Moreover, the role of MT as antioxidative, participating in biological rhythm regulation, was also reviewed. Furthermore, the effects of MT on various ovarian related diseases were analyzed, particularly for the ovarian aging and polycystic ovary syndrome (PCOS).

Do sleep changes mediate the anti-depressive and anti-suicidal response of intravenous ketamine in treatment-resistant depression?

Sleep disturbances are commonly reported in patients with treatment-resistant depression (TRD). Available data have shown that intravenous (IV) ketamine is an effective treatment for patients with TRD and growing data suggest ketamine may improve overall sleep architecture. In the present study, we evaluated whether changes in sleep symptoms mediated the anti-depressive and/or anti-suicidal effects of IV ketamine and whether improvement in sleep correlated with a higher likelihood of achieving response or remission. Adults with TRD received four infusions of IV ketamine at a community-based clinic. Total depressive symptom severity was measured with the Quick Inventory Depressive Symptoms Self-Report 16-Item (QIDS-SR₁₆ ) at baseline and was repeated across four infusions. Suicidal ideation (SI) and four sleep symptoms were measured using the SI item and the five sleep items on the QIDS-SR₁₆ . A total of 323 patients with TRD received IV ketamine. Self-reported improvements in insomnia, night-time restlessness, hypersomnia, early morning waking, and total sleep were significant partial mediators to the improvements observed in depression severity. Similarly, insomnia, night-time restlessness, early morning waking and total sleep improvements mediated the reduction of IV ketamine on SI. All sleep items, except for hypersomnia, were associated with an increased likelihood of achieving response or remission. Notably, each point improvement in total sleep score was significantly associated with achieving responder/remitter status (odds ratio 3.29, 95% confidence interval 2.00-5.41). Insomnia, sleep restlessness, early morning waking and total sleep improvements were significant mediators of antidepressant and anti-suicidal improvements in patients with TRD receiving IV ketamine.

Molecular Regulation of the Melatonin Biosynthesis Pathway in Unipolar and Bipolar Depression

Melatonin is a neurohormone that maintains the circadian rhythms of the body. By regulating the secretion of other hormones and neurotransmitters, it acts as a pleiotropic modulator that affects, for example, reproductive, immune, cardiovascular, sleep, and wake systems and mood. Thus, synthetic melatonin has become an essential component in the treatment of depressive disorders. Although we know the pathway of melatonin action in the brain, we lack comprehensive cross-sectional studies on the periphery of depressed patients. This study aimed to comprehensively analyze the differences between healthy control subjects (n = 84) and unipolar and bipolar depression patients (n = 94), including an analysis of the melatonin pathway at the level of the genes and serum biomarkers. An innovative approach is a pilot study based on gene expression profiling carried out on clinical and cell culture models using agomelatine and melatonin. We confirmed the melatonin biosynthesis pathway's molecular regulation dysfunctions, with a specific pattern for unipolar and bipolar depression, at the AANAT gene, its polymorphisms (rs8150 and rs3760138), and examined the serum biomarkers (serotonin, AANAT, ASMT, and melatonin). The biological pathway analysis uncovered pathways and genes that were uniquely altered after agomelatine treatment in a clinical model and melatonin treatment in a cell culture model. In both models, we confirmed the immunomodulatory effect of melatonin agents in depression.

Social defeat stress affects resident's clock gene and bdnf expression in the brain

Social defeat stress affects behavior and changes the expression of the genes underlying neuronal plasticity in the brain. The circadian clock regulates most neuronal processes in the brain, which results in daily variations of complex behavior, and any disturbance in circadian clock oscillations increases the risk of mood and cognitive disbalance. In this study, we assessed the effect of acute and repeated social defeat stress on Per2 and Nr1d1 expression in prefrontal cortexes, hippocampi, pineal glands, olfactory bulbs, cerebella, and pituitary glands. We also evaluated the effect of our experimental setting on levels of Bdnf and plasma corticosterone, two markers widely used to asses the impact of stress on mammalian physiology. Our data show that single and repeated social defeat stress upregulates the expression of both clock genes and Bdnf in all brain structures, and corticosterone in the blood. While the general pattern of Bdnf upregulation suggests higher sensitivity in the intruder group, the clock genes are induced more significantly in residents, especially by repeated stress sessions. Our work thus suggests that the model of stress-induced anxiety and depression should consider a group of residents because, for some parameters, they may respond more distinctively than intruders.LAY SUMMARYThe resident/intruder experimental paradigm affects the expression of clock genes Per2, Nr1d1and Bdnf in the brain structures and plasma corticosterone level. The induction of clock genes is evident in both experimental groups; however, it is more marked in residents. Together with the significant increase in Bdnf levels in the majority of brain structures and plasma corticosterone in residents, our data suggest that in the model of social defeat stress, the utility of an experimental group of residents could be contributive.

The circadian machinery links metabolic disorders and depression: A review of pathways, proteins and potential pharmacological interventions

Circadian rhythms are responsible for regulating a number of physiological processes. The central oscillator is located within the suprachiasmatic nucleus (SCN) of the hypothalamus and the SCN synchronises the circadian clocks that are found in our peripheral organs through neural and humoral signalling. At the molecular level, biological clocks consist of transcription-translation feedback loops (TTFLs) and these pathways are influenced by transcription factors, post-translational modifications, signalling pathways and epigenetic modifiers. When disruptions occur in the circadian machinery, the activities of the proteins implicated in this network and the expression of core clock or clock-controlled genes (CCGs) can be altered. Circadian misalignment can also arise when there is desychronisation between our internal clocks and environmental stimuli. There is evidence in the literature demonstrating that disturbances in the circadian rhythm contribute to the pathophysiology of several diseases and disorders. This includes the metabolic syndrome and recently, it has been suggested that the 'circadian syndrome' may be a more appropriate term to use to not only describe the cardio-metabolic risk factors but also the associated comorbidities. Here we overview the molecular architecture of circadian clocks in mammals and provide insight into the effects of shift work, exposure to artificial light, food intake and stress on the circadian rhythm. The relationship between circadian rhythms, metabolic disorders and depression is reviewed and this is a topic that requires further investigation. We also describe how particular proteins involved in the TTFLs can be potentially modulated by small molecules, including pharmacological interventions and dietary compounds.

Circadian disruption, melatonin rhythm perturbations and their contributions to chaotic physiology

The aim of this report is to summarize the data documenting the vital nature of well-regulated cellular and organismal circadian rhythms, which are also reflected in a stable melatonin cycle, in supporting optimal health. Cellular fluctuations in physiology exist in most cells of multicellular organisms with their stability relying on the prevailing light:dark cycle, since it regulates, via specialized intrinsically-photoreceptive retinal ganglion cells (ipRGC) and the retinohypothalamic tract, the master circadian oscillator, i.e., the suprachiasmatic nuclei (SCN). The output message of the SCN, as determined by the light:dark cycle, is transferred to peripheral oscillators, so-called slave cellular oscillators, directly via the autonomic nervous system with its limited distribution. and indirectly via the pineal-derived circulating melatonin rhythm, which contacts every cell. Via its regulatory effects on the neuroendocrine system, particularly the hypothalamo-pituitary-adrenal axis, the SCN also has a major influence on the adrenal glucocorticoid rhythm which impacts neurological diseases and psychological behaviors. Moreover, the SCN regulates the circadian production and secretion of melatonin. When the central circadian oscillator is disturbed, such as by light at night, it passes misinformation to all organs in the body. When this occurs the physiology of cells becomes altered and normal cellular functions are compromised. This physiological upheaval is a precursor to pathologies. The deterioration of the SCN/pineal network is often a normal consequence of aging and its related diseases, but in today's societies where manufactured light is becoming progressively more common worldwide, the associated pathologies may also be occurring at an earlier age.

Changes of Serum Melatonin, Interleukin-6, Homocysteine, and Complement C3 and C4 Levels in Patients With Depression

Objectives

Cytokine activation and low complement levels are common in depression patients. This study is aimed at investigating the clinical significance of changes in serum concentrations of melatonin (MT), interleukin-6 (IL-6), homocysteine (hcy), and complement C3 and C4 in depression patients and relationships of them with depression activity.

Methods

A total of 95 depression patients, including first-episode group (n = 43) and recurrent group (n = 52), and 45 age- and gender-matched healthy controls (HC) were recruited. Serum levels of MT, IL-6, hcy, C3, and C4 in all samples were measured by using enzyme-linked immunosorbent assay (ELISA), chemiluminescence method, enzyme circulation method, and immuno-scatter turbidimetric assay, respectively.

Results

The serum MT, IL-6, and hcy levels in the first-episode group (113.08 ± 5.06 pg/ml, 2.06 ± 0.12 ng/L, and 13.87 ± 0.45 μmol/L), and recurrent group (117.63 ± 4.63 pg/ml, 2.20 ± 0.12 ng/L, and 13.61 ± 0.46 μmol/L) were significantly higher than those in the control group (89.50 ± 5.10 pg/ml, 1.57 ± 0.06 ng/L, and 11.34 ± 0.40 μmol/L). The serum levels of C3 in the first-episode group (0.95 ± 0.02 ng/L) were significantly lower than those in the recurrent group (1.05 ± 0.03 ng/L) and control group (1.12 ± 0.03 ng/L). There was no significant difference in serum C4 level between each group.

Conclusion

These results suggest that higher serum MT, IL-6, and hcy levels were correlated with pathogenesis of depression.

Clinical impact of melatonin on breast cancer patients undergoing chemotherapy; effects on cognition, sleep and depressive symptoms: A randomized, double-blind, placebo-controlled trial

This randomized, double-blinded, placebo-controlled trial tested the hypothesis that 20mg of melatonin before and during the first cycle of adjuvant chemotherapy for breast cancer (ACBC) reduced the side effects associated with cognitive impairment. We evaluated the effects of melatonin on cognition, depressive symptoms and sleep quality, and whether these effects were related to serum levels of Brain Derived Neurotrophic Factor (BDNF) and its receptor, tropomyosin kinase B (TrkB). Thirty-six women were randomly assigned to receive melatonin or placebo for 10 days. To evaluate cognitive performance, we used the Trail-Making-Test Parts A and B (A-B), Rey Auditory-Verbal Learning Test (RAVLT), Controlled Oral Word Association Test (COWAT) and an inhibitory task type Go / No-Go. Our results revealed that melatonin improved executive function on TMT scores, enhanced episodic memory (immediate and delayed) and recognition on RAVLT, and increased verbal fluency in the orthographic COWAT. The TMT-A-B(A-B) were negatively correlated with baseline levels of TrkB and BDNF, respectively. At the end of treatment, changes in TrkB and BDNF were inversely associated with depressive symptoms and sleep quality, but not with the TMT scores. These results suggest a neuroprotective effect of melatonin to counteract the adverse effects of ACBC on cognitive function, sleep quality and depressive symptoms.

Efficacy and Safety of Melatonin Treatment in Children with Autism Spectrum Disorder and Attention-Deficit/Hyperactivity Disorder-A Review of the Literature

Autism spectrum disorder (ASD) and attention-deficit/hyperactivity disorder (ADHD) are neurodevelopmental disorders with disturbed melatonin secretion profile and sleep problems. The growing incidence of ASD and ADHD inspires scientists to research the underlying causes of these conditions. The authors focused on two fundamental aspects, the first one being the presentation of the role of melatonin in ASD and ADHD and the second of the influence of melatonin treatment on sleep disorders. The authors present the use of melatonin both in the context of causal and symptomatic treatment and discuss melatonin supplementation: Dosage patterns, effectiveness, and safety. Sleep disorders may have a different clinical picture, so the assessment of exogenous melatonin efficacy should also refer to a specific group of symptoms. The review draws attention to the wide range of doses of melatonin used in supplementation and the need to introduce unified standards especially in the group of pediatric patients.

Pineal Gland Volume in Major Depressive and Bipolar Disorders

Abnormal melatonin secretion has been demonstrated in patients with affective disorders such as major depressive disorder (MDD) and bipolar disorder (BD). However, magnetic resonance imaging (MRI) studies that previously investigated the volume of the pineal gland, which regulates circadian rhythms by secreting melatonin, in these patients reported inconsistent findings. The present study employed MRI to examine pineal gland volumes and pineal cyst prevalence in 56 MDD patients (29 currently depressed and 27 remitted patients), 26 BD patients, and matched controls (33 for MDD and 24 for BD). Pineal volumes and cyst prevalence in the current MDD, remitted MDD, and BD groups did not significantly differ from those of the healthy controls. However, pineal gland volumes were significantly smaller in the current MDD subgroup of non-melancholic depression than in the melancholic MDD subgroup. Interestingly, pineal volumes correlated negatively with the severity of loss of interest in the current MDD group. Medication and the number of affective episodes were not associated with pineal volumes in the MDD or BD group. While these results do not suggest that pineal volumes reflect abnormal melatonin secretion in affective disorders, they do point to the possibility that pineal abnormalities are associated with clinical subtypes of MDD and its symptomatology.

Qualidade e duração de sono entre usuários da rede pública de saúde

Resumo Objetivo Avaliar a qualidade e tempo de sono entre usuários da rede pública de saúde e fatores associados. Métodos Estudo transversal, realizado com 775 indivíduos de ambos os sexos, em um município da região Centro-Oeste do Brasil. Aplicou-se questionário semiestruturado para avaliar as características sociodemográficas, os hábitos de vida, as condições de saúde, o binge drinking e qualidade e duração do sono, avaliadas pelo Índice de Qualidade de Sono de Pittsburgh. Aplicou-se a regressão de Poisson para identificação dos fatores associados à qualidade do sono ruim e à duração de sono (curta e longa). Resultados Na análise múltipla, os fatores associados à qualidade de sono ruim foram sexo feminino (razão de prevalência: 1,10; intervalo e confiança de 95% − IC95% 1,05-1,16; p<0,00), binge drinking (razão de prevalência: 1,08; IC95% 1,03-1,13; p<0,01), uso de substâncias ilícitas (razão de prevalência: 1.06, IC95% 1.00-1.12; p=0.03), angina (razão de prevalência: 1,10;, IC95% 1,03-1,18; p<0,01) e depressão (razão de prevalência: 1,07 IC95% 1,00-1,14; p=0,02). A obesidade associou-se à curta duração do sono (razão de prevalência: 1,10 IC95% 1,02-1,17; p<0,01). Idade > 55 anos associou-se à longa duração do sono (razão de prevalência: 1,39, IC95% 1,00-1,92; p=0,04). Conclusão Ser mulher, ter idade >55 anos, consumir bebida alcoólica, usar substâncias ilícitas, angina, obesidade e depressão foram fatores de risco para alterações na qualidade e duração de sono. Os resultados do presente estudo reforçam a necessidade do desenvolvimento de ações voltadas para a prevenção dos agravos relacionados às alterações no sono na população estudada.

Pineal gland abnormality in major depressive disorder

Patients with major depressive disorder (MDD) often have circadian rhythm alteration and sleep disturbance. The pineal gland regulates the circadian rhythm and sleep by the secretion of melatonin neurohormone. However, the relationship between pineal abnormality and MDD remains elusive. 50 patients with MDD and 35 gender- and age-matched healthy controls underwent high-resolution structural MRI. Pineal parenchymal volume (PPV) was measured manually. Inter-group differences in prevalence of pineal cyst and PPV were examined. In addition, we investigated the correlations between PPV and symptom severity as well as sleep variables in the patient group. Compared to healthy controls, patients with MDD had a higher prevalence of pineal cyst. Moreover, patients had significantly decreased PPV relative to controls. However, no significant correlations were observed between PPV and symptom severity as well as sleep variables. Our findings suggest that pineal abnormality may play a critical role in depression.

Mental health in elite athletes: International Olympic Committee consensus statement (2019)

Mental health symptoms and disorders are common among elite athletes, may have sport related manifestations within this population and impair performance. Mental health cannot be separated from physical health, as evidenced by mental health symptoms and disorders increasing the risk of physical injury and delaying subsequent recovery. There are no evidence or consensus based guidelines for diagnosis and management of mental health symptoms and disorders in elite athletes. Diagnosis must differentiate character traits particular to elite athletes from psychosocial maladaptations.

Management strategies should address all contributors to mental health symptoms and consider biopsychosocial factors relevant to athletes to maximise benefit and minimise harm. Management must involve both treatment of affected individual athletes and optimising environments in which all elite athletes train and compete. To advance a more standardised, evidence based approach to mental health symptoms and disorders in elite athletes, an International Olympic Committee Consensus Work Group critically evaluated the current state of science and provided recommendations.