Olanzapine-induced early cardiovascular effects are mediated by the biological clock and prevented by melatonin

A matter of time: A systematic scoping review on a potential role of the circadian system in binge eating behavior

Background

Emerging research suggests that food intake timing, eating behavior and food preference are associated with aspects of the circadian system function but the role that the circadian system may play in binge eating (BE) behavior in humans remains unclear.

Objective

To systematically evaluate the evidence for circadian system involvement in BE behavior.

Methods

Systematic searches of PubMed, EMBASE, and Scopus were performed for reports published from inception until May 2020 (PROSPERO Registration CRD42020186325). Searches were conducted by combining Medical Subject Headings related to the circadian system, BE behavior, and/or interventions. Observational and interventional studies in humans with BE behavior published in peer-review journals in the English language were included. Studies were assessed using quality and risk of bias tools (AXIS, ROB 2.0, or ROBINS).

Results

The search produced 660 articles, 51 of which were included in this review. Of these articles, 46 were observational studies and 5 were interventional trials. Evidence from these studies suggests that individuals with BE behavior tend to have more food intake, more binge cravings, and more BE episodes later in the day. Hormonal and day/night locomotor activity rhythm disturbances may be associated with BE behavior. Furthermore, late diurnal preference ("eveningness") was associated with BE behavior and chronobiological interventions that shift the circadian clock earlier (e.g., morning bright light therapy) were found to possibly decrease BE behavior. Substantive clinical overlap exists between BE and night eating behavior. However, there is a significant knowledge gap regarding their potential relationship with the circadian system. Limitations include the lack of studies that use best-established techniques to assess the chronobiology of BE behavior, heterogeneity of participants, diagnostic criteria, and study design, which preclude a meta-analytic approach.

Conclusion

Current evidence, although limited, suggests that the circadian system may play a role in the etiology of BE behavior. Further mechanistic studies are needed to fully characterize a potential role of the circadian system in BE behavior. A chronobiological approach to studying BE behavior may lead to identification of its neurobiological components and development of novel therapeutic interventions.

Systematic review registration

[https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42020186325], identifier [CRD42020186325].

Antipsychotic-induced weight gain and metabolic effects show diurnal dependence and are reversible with time restricted feeding

Antipsychotic drugs (AP) are highly efficacious treatments for psychiatric disorders but are associated with significant metabolic side-effects. The circadian clock maintains metabolic homeostasis by sustaining daily rhythms in feeding, fasting and hormone regulation but how circadian rhythms interact with AP and its associated metabolic side-effects is not well-known. We hypothesized that time of AP dosing impacts the development of metabolic side-effects. Weight gain and metabolic side-effects were compared in C57Bl/6 mice and humans dosed with APs in either the morning or evening. In mice, AP dosing at the start of the light cycle/rest period (AM) resulted in significant increase in food intake and weight gain compared with equivalent dose before the onset of darkness/active period (PM). Time of AP dosing also impacted circadian gene expression, metabolic hormones and inflammatory pathways and their diurnal expression patterns. We also conducted a retrospective examination of weight and metabolic outcomes in patients who received risperidone (RIS) for the treatment of serious mental illness and observed a significant association between time of dosing and severity of RIS-induced metabolic side-effects. Time restricted feeding (TRF) has been shown in both mouse and some human studies to be an effective therapeutic intervention against obesity and metabolic disease. We demonstrate, for the first time, that TRF is an effective intervention to reduce AP-induced metabolic side effects in mice. These studies identify highly effective and translatable interventions with potential to mitigate AP-induced metabolic side effects.

Multifaceted interconnections between macrophage migration inhibitory factor and psychiatric disorders

Inflammation is involved in the pathogenesis of psychiatric disorders. Many previous studies have defined the important roles of inflammatory factors in the pathogenesis, diagnosis, and treatment outcomes of psychiatric disorders. Macrophage migration inhibitory factor (MIF), a pro-inflammatory factor, has been gradually recognized to be involved in the development of neurological diseases in recent years. Our current review focuses on discussing the potential beneficial and detrimental roles of MIF in psychiatric disorders. We will provide new mechanistic insights for the development of potential diagnostic and therapeutic biomarkers based on MIF for psychiatric diseases.

Circadian rhythm disruptions: A possible link of bipolar disorder and endocrine comorbidities

Epidemiological studies have demonstrated an association between bipolar disorder (BP) and endocrine diseases. Further, circadian rhythm disruptions may be a potential common pathophysiological mechanism of both disorders. This review provides a brief overview of the molecular mechanisms of circadian rhythms, as well as roles circadian rhythms play in BP and common endocrine comorbidities such as diabetes and thyroid disease. Treatments targeting the circadian system, both pharmacological and non-pharmacological, are also discussed. The hope is to elicit new interest to the importance of circadian system in BP and offer new entry points and impetus to the development of medicine.

The circadian system: From clocks to physiology

The circadian system, composed of the central autonomous clock, the suprachiasmatic nucleus (SCN), and systems of the body that follow the signals of the SCN, continuously change the homeostatic set points of the body over the day-night cycle. Changes in the body's physiological state that do not agree with the time of the day feedback to the hypothalamus, and provide input to the SCN to adjust the condition, thus reaching another set point required by the changed conditions. This allows the adjustment of the set points to another level when environmental conditions change, which is thought to promote adaptation and survival. In fasting, the body temperature drops to a lower level only at the beginning of the sleep phase. Stressful conditions raise blood pressure relatively more during the active period than during the rest phase. Extensive, mostly reciprocal SCN interactions, with hypothalamic networks, induce these physiological adjustments by hormonal and autonomic control of the body's organs. More importantly, in addition to SCN's hormonal and autonomic influences, SCN induced behavior, such as rhythmic food intake, induces the oscillation of many genes in all tissues, including the so-called clock genes, which have an essential role as a transcriptional driving force for numerous cellular processes. Consequently, the light-dark cycle, the rhythm of the SCN, and the resulting rhythm in behavior need to be perfectly synchronized, especially where it involves synchronizing food intake with the activity phase. If these rhythms are not synchronous for extended periods of times, such as during shift work, light exposure at night, or frequent night eating, disease may develop. As such, our circadian system is a perfect illustration of how hypothalamic-driven processes depend on and interact with each other and need to be in seamless synchrony with the body's physiology.

Potential Role of Melatonin as an Adjuvant for Atherosclerotic Carotid Arterial Stenosis

Carotid artery stenosis (CAS) is an atherosclerotic disease characterized by a narrowing of the artery lumen and a high risk of ischemic stroke. Risk factors of atherosclerosis, including smoking, hypertension, hyperglycemia, hyperlipidemia, aging, and disrupted circadian rhythm, may potentiate atherosclerosis in the carotid artery and further reduce the arterial lumen. Ischemic stroke due to severe CAS and cerebral ischemic/reperfusion (I/R) injury after the revascularization of CAS also adversely affect clinical outcomes. Melatonin is a pluripotent agent with potent anti-inflammatory, anti-oxidative, and neuroprotective properties. Although there is a shortage of direct clinical evidence demonstrating the benefits of melatonin in CAS patients, previous studies have shown that melatonin may be beneficial for patients with CAS in terms of reducing endothelial damage, stabilizing arterial plaque, mitigating the harm from CAS-related ischemic stroke and cerebral I/R injury, and alleviating the adverse effects of the related risk factors. Additional pre-clinical and clinical are required to confirm this speculation.

The use of melatonin to mitigate the adverse metabolic side effects of antipsychotics

Antipsychotic drugs are efficacious first-line treatments for many individuals diagnosed with a psychiatric illness. However, their adverse metabolic side-effect profile, which resembles the metabolic syndrome, represents a significant clinical problem that increases morbidity and limits treatment adherence. Moreover, the mechanisms involved in antipsychotic-induced adverse metabolic effects (AMEs) are unknown and mitigating strategies and interventions are limited. However, recent clinical trials show that nightly administration of exogenous melatonin may mitigate or even prevent antipsychotic-induced AMEs. This clinical evidence in combination with recent preclinical data implicate the circadian system in antipsychotic-induced AMEs and their mitigation. In this chapter, we provide an overview on the circadian system and its involvement in antipsychotic-induced AMEs, as well as the potential beneficial effect of nightly melatonin administration to mitigate them.

Melatonin Suppresses Ferroptosis Induced by High Glucose via Activation of the Nrf2/HO-1 Signaling Pathway in Type 2 Diabetic Osteoporosis

Ferroptosis is recently identified, an iron- and reactive oxygen species- (ROS-) dependent form of regulated cell death. This study was designed to determine the existence of ferroptosis in the pathogenesis of type 2 diabetic osteoporosis and confirm that melatonin can inhibit the ferroptosis of osteoblasts through activating Nrf2/HO-1 signaling pathway to improve bone microstructure in vivo and in vitro. We treated MC3T3-E1 cells with different concentrations of melatonin (1, 10, or 100 μM) and exposed them to high glucose (25.5 mM) for 48 h in vitro. Our data showed that high glucose can induce osteoblast cytotoxicity and the accumulation of lipid peroxide, the mitochondria of osteoblast show the same morphology changes as the erastin treatment group, and the expression of ferroptosis-related proteins glutathione peroxidase 4 (GPX4) and cystine-glutamate antiporter (SLC7A11) is downregulated, but these effects were reversed by ferroptosis inhibitor ferrastatin-1 and iron chelator deferoxamine (DFO). Furthermore, western blot and real-time polymerase chain reaction were used to detect the expression levels of nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1); osteogenic capacity was evaluated by alizarin red S staining and the expression of osteoprotegerin, osteocalcin, and alkaline phosphatase; the results showed that the expression levels of these proteins in osteoblasts with 1, 10, or 100 μM melatonins were significantly higher than the high glucose group, but after using Nrf2-SiRNA interference, the therapeutic effect of melatonin was significantly inhibited. We also performed in vivo experiments in a diabetic rat model treated with two concentrations of melatonin (10, 50 mg/kg). Dynamic bone histomorphometry and micro-CT were used to observe the rat bone microstructure, and the expression of GPX4 and Nrf2 was determined by immunohistochemistry. Here, we first report that high glucose induces ferroptosis via increased ROS/lipid peroxidation/glutathione depletion in type 2 diabetic osteoporosis. More importantly, melatonin significantly reduced the level of ferroptosis and improved the osteogenic capacity of MC3T3-E1 through activating the Nrf2/HO-1 pathway in vivo and in vitro.

Melatonin Plays a Critical Protective Role in Nicotine-Related Abdominal Aortic Aneurysm

Aim: Smoking is a major risk factor for abdominal aortic aneurysm (AAA). Among the components of smoke, nicotine is known to exert pro-atherosclerotic, prothrombotic, and proangiogenic effects on vascular smooth muscle cells (VSMCs). The current study was designed to investigate the mechanisms through which nicotine induces vascular wall dysfunction and to examine whether melatonin protects against nicotine-related AAA. Methods: In this study, an enzyme-linked immunosorbent assay (ELISA) was used to measure melatonin and TNF-α levels, as well as total antioxidant status (TAS), in patients with AAA. We established a nicotine-related AAA model and explored the mechanisms underlying the therapeutic effects of melatonin. Tissue histopathology was used to assess vascular function, while western blotting (WB) and immunofluorescence staining were performed to detect protein expression. Results: We observed melatonin insufficiency in the serum from patients with AAA, particularly smokers. Moreover, melatonin level was positively correlated with antioxidant capacity. In the in vivo model, nicotine accelerated AAA expansion and destroyed vascular structure. Furthermore, OPN, LC3II, p62, matrix metalloproteinase-2 (MMP-2), matrix metalloproteinase-9 (MMP-9), NF-κB p65, TNF-α, phosphorylated AKT, and phosphorylated mTOR levels were increased, in vivo, following nicotine treatment, while SM22α and α-SMA levels were reduced. Additionally, melatonin attenuated the effects of nicotine on AAA and reversed changes in protein expression. Moreover, melatonin lost its protective effects following bafilomycin A1-mediated inhibition of autophagy. Conclusion: Based on our data, melatonin exerts a beneficial effect on rats with nicotine-related AAA by downregulating the AKT-mTOR signaling pathway, improving autophagy dysfunction, and restoring the VSMC phenotype.

Evening chronotype as a discrete clinical subphenotype in bipolar disorder

OBJECTIVE

Our aim was to investigate evening chronotype, a proxy marker of circadian system dysfunction, as a clinical subphenotype in bipolar disorder (BD).

METHODS

In this cross-sectional study, 773 BD participants and 146 control subjects were evaluated using the Structured Clinical Interview for DSM-IV and a set of questionnaires. Chronotype was determined using item-5 from the reduced Morningness-Eveningness Questionnaire. Univariate analyses and regression models were used to compare evening and non-evening chronotype in BD and chronotype association with clinical variables.

RESULTS

Overall, 205 (27%) of BD patients reported an evening chronotype. Evening chronotype was higher in a matched sub-sample of BD patients (n = 150) than in controls (24% and 5% respectively, OR=5.4, p<0.01). Compared to those with non-evening chronotypes, BD patients with an evening chronotype were younger, had an earlier age of onset of BD, and had more prior depressive and manic episodes, higher rates of rapid cycling, past suicide attempts, more comorbid anxiety and substance use disorders. Multivariate regression showed age, prior suicide attempts, and co-occurring substance use disorder were associated with evening chronotype (OR range of 0.97 to1.59). Hypertension, migraine, asthma, and obstructive sleep apnea were significantly associated with evening chronotype (OR range of 1.56 to 2.0).

LIMITATION

Limitations include a cross-sectional study design that precludes establishing causality. Analyses did not control for medication use. Younger participant age may prevent evaluation of associations with late-life illnesses.

CONCLUSIONS

Evening chronotype may be a discrete clinical subphenotype in BD and circadian dysfunction a shared pathophysiological mechanism between psychopathology and medical morbidity.

Dopamine D2 receptor signaling modulates pancreatic beta cell circadian rhythms

Antipsychotic drugs (APD) have clinically important, adverse effects on metabolism that limit their therapeutic utility. Pancreatic beta cells produce dopamine and express the D₂ dopamine receptor (D2R). As D2R antagonists, APDs alter glucose-stimulated insulin secretion, indicating that dopamine likely plays a role in APD-induced metabolic dysfunction. Insulin secretion from beta cells is also modulated by the circadian clock. Disturbed circadian rhythms cause metabolic disturbances similar to those observed in APD-treated subjects. Given the importance of dopamine and circadian rhythms for beta cells, we hypothesized that the beta cell dopamine system and circadian clock interact and dually regulate insulin secretion, and that circadian manipulations may alter the metabolic impact of APDs. We measured circadian rhythms, insulin release, and the impact of dopamine upon these processes in beta cells using bioluminescent reporters. We then assessed the impact of circadian timing on weight gain and metabolic outcomes in mice treated with the APD sulpiride at the onset of light or dark. We found that molecular components of the dopamine system were rhythmically expressed in beta cells. D2R stimulation by endogenous dopamine or the agonist bromocriptine reduced circadian rhythm amplitude, and altered the temporal profile of insulin secretion. Sulpiride caused greater weight gain and hyperinsulinemia in mice when given in the dark phase compared to the light phase. D2R-acting drugs affect circadian-dopamine interactions and modulate beta cell metabolic function. These findings identify circadian timing as a novel and important mechanism underlying APD-induced metabolic dysfunction, offering new possibilities for therapeutic interventions.

The Protective Effects of Melatonin Against LPS-Induced Septic Myocardial Injury: A Potential Role of AMPK-Mediated Autophagy

Aim: Melatonin is an indolamine secreted by the pineal gland, as well as most of the organs and tissues. In addition to regulating circadian biology, studies have confirmed the multiple pharmacological effects of melatonin. Melatonin provides a strong defense against septic myocardial injury. However, the underlying mechanism has not been fully described. In this study, we investigated the protective effects of melatonin against lipopolysaccharide (LPS)-induced myocardial injury as well as the mechanisms involved. Methods: Mice were intraperitoneally injected with LPS to induce a septic myocardial injury model or an LPS shock model, depending on the dose of LPS. Melatonin was given (20 mg/kg/day, via intraperitoneal injection) for a week prior to LPS insult. 6 h after LPS injection, echocardiographic analysis, TUNEL staining, transmission electron microscopy (TEM), western blot, quantitative real-time PCR and ELISA were used to investigate the protective effects of melatonin against LPS induced myocardial injury. AMPK inhibitor, autophagy activator and inhibitor, siRNAs were used for further validation. Results: Survival test showed that melatonin significantly increased the survival rate after LPS-induced shock. In the sepsis model, melatonin markedly ameliorated myocardial dysfunction, decreased the release of inflammatory cytokines, activated AMP-activated protein kinase (AMPK), improved mitochondrial function, and activated autophagy. To confirm whether the protection of melatonin was mediated by AMPK and autophagy, Compound C, an AMPK inhibitor; 3-MA, an autophagy inhibitor; and Rapamycin (Rapa), an autophagy activator, were used in this study. AMPK inhibition down-regulated autophagy, abolished protection of melatonin, as indicated by significantly decreased cardiac function, increased inflammation and damaged mitochondrial function. Furthermore, autophagy inhibition by 3-MA significantly impaired the protective effects of melatonin, whereas autophagy activation by Rapa reversed LPS + Compound C induced myocardial injury. In addition, in vitro studies further confirmed the protection of melatonin against LPS-induced myocardial injury and the mechanisms involving AMPK-mediated autophagy signaling. Conclusions: In summary, our results demonstrated that melatonin protects against LPS-induced septic myocardial injury by activating AMPK mediated autophagy pathway.

Inhibition of A-Type K+ Channels by Urotensin-II Induces Sensory Neuronal Hyperexcitability Through the PKCα-ERK Pathway

Previous studies have implicated urotensin-II in the nociception of sensory neurons. However, to date the relevant mechanisms remain unknown. In the current study we determined the role of urotensin-II in the regulation of transient outward A-type potassium currents (IA) and neuronal excitability in trigeminal ganglion (TG) neurons. We found that application of urotensin-II to small-diameter TG neurons decreased IA in a dose-dependent manner, whereas the delayed rectifier potassium current was unaffected. The IA decrease induced by urotensin-II depended on the urotensin-II receptor (UT-R) and was associated with a hyperpolarizing shift in the steady-state inactivation curve. Exposure of TG cells to urotensin-II markedly increased protein kinase C (PKC) activity, and PKC inhibition eliminated the UT-R-mediated IA decrease. Antagonism of PKCα, either pharmacologically or genetically, but not of PKCβ prevented the decrease in IA induced by urotensin-II. Analysis of phospho-extracellular signal-regulated kinase (p-ERK) revealed that urotensin-II significantly increased the expression level of p-ERK, whereas p-p38 and p-c-Jun N-terminal kinase remained unchanged. Inhibition of mitogen-activated protein kinase/ERK signaling by the kinase antagonist U0126 and PD98059 completely abolished the UT-R-mediated IA decrease. Moreover, urotensin-II significantly increased the action potential firing rate of small TG neurons; pretreatment with 4-aminopyridine prevented this effect. In summary, our findings suggest that urotensin-II selectively attenuated IA through stimulation of the PKCα-dependent ERK1/2 signaling pathway. This UT-R-dependent mechanism might contribute to neuronal hyperexcitability in TG neurons.

Protective role of melatonin in cardiac ischemia-reperfusion injury: From pathogenesis to targeted therapy

Acute myocardial infarction (MI) is a major cause of mortality and disability worldwide. In patients with MI, the treatment option for reducing acute myocardial ischemic injury and limiting MI size is timely and effective myocardial reperfusion using either thombolytic therapy or primary percutaneous coronary intervention (PCI). However, the procedure of reperfusion itself induces cardiomyocyte death, known as myocardial reperfusion injury, for which there is still no effective therapy. Recent evidence has depicted a promising role of melatonin, which possesses powerful antioxidative and anti-inflammatory properties, in the prevention of ischemia-reperfusion (IR) injury and the protection against cardiomyocyte death. A number of reports explored the mechanism of action behind melatonin-induced beneficial effects against myocardial IR injury. In this review, we summarize the research progress related to IR injury and discuss the unique actions of melatonin as a protective agent. Furthermore, the possible mechanisms responsible for the myocardial benefits of melatonin against reperfusion injury are listed with the prospect of the use of melatonin in clinical application.