Inter-relationships of the chronobiotic, melatonin, with leptin and adiponectin: implications for obesity

Melatonin's Role in Hair Follicle Growth and Development: A Cashmere Goat Perspective

Hair follicles, unique skin appendages, undergo cyclic phases (anagen, catagen, telogen) governed by melatonin and associated molecular pathways. Melatonin, synthesized in the pineal gland, skin, and gut, orchestrates these cycles through antioxidant activity and signaling cascades (e.g., Wnt, BMP). This review examines melatonin's biosynthesis across tissues, its regulation of cashmere growth patterns, and its interplay with non-coding RNAs and the gut-skin axis. Recent advances highlight melatonin's dual role in enhancing antioxidant capacity (via Keap1-Nrf2) and modulating gene expression (e.g., Wnt10b, CTNNB1) to promote hair follicle proliferation. By integrating multi-omics insights, we construct a molecular network of melatonin's regulatory mechanisms, offering strategies to improve cashmere yield and quality while advancing therapies for human alopecia.

Selected Biochemical, Hematological, and Immunological Blood Parameters for the Identification of Malnutrition in Polish Senile Inpatients: A Cross-Sectional Study

Background/Objectives: Malnutrition in senile patients leads to functional disability while reducing quality of life. Medical professionals should routinely assess their nutritional status during hospitalization. However, diagnosing malnutrition may be difficult, especially since obesity may mask malnourishment. Thus, it is essential to search for biomarkers that improve the identification of malnourished inpatients. Methods: In the present cross-sectional study, selected venous blood parameters were analyzed in 137 older inpatients at the age of 80.5 ± 7.78 admitted to the Geriatrics Clinic of the Antoni Jurasz University Hospital No. 1 in Bydgoszcz, Poland between 2017 and 2018, for a comprehensive geriatric assessment. The participants were grouped according to their nutritional risks based on the Mini Nutritional Assessment (MNA) and the Geriatric Nutrition Risk Index (GNRI). The Kruskal-Wallis test was utilized to evaluate the equality of variances for a variable calculated for two or more groups. The level of significance was set at p < 0.05. Results: For total protein, albumin, homocysteine, hemoglobin, hematocrit, total magnesium, total calcium, C-reactive protein (CRP), interleukin 6 (IL-6), and interferon γ-induced protein 10 (IP-10), statistically significant differences were found between groups of patients classified by the MNA. However, additional significant differences were also observed for creatinine, folic acid, and triglycerides, according to the GNRI compartmentalization. The results indicate that decreased levels of albumin (<3 g/dL) and hemoglobin (<11 g/dL), along with elevated homocysteine, CRP, IL-6 (>7.5 pg/mL), and IP-10 (>250 pg/mL), should alert medical professionals to potential malnutrition in hospitalized patients. Conclusions: Routine analysis of venous blood parameters can help rapidly identify malnutrition and the immediate implementation of a specialized diet.

Melatonin-Supplemented Obese Female Mice Show Less Inflammation in Ovarian Adipocytes and Browning in Subcutaneous Adipocytes

We hypothesized that melatonin (Mel) supplementation may offer therapeutic benefits for obesity, particularly in women. Therefore, the study evaluated Mel's effects on white adipose tissue (WAT) in diet-induced obese female mice. Four-week-old C57BL/6 females were assigned to either a control diet (C group) or a high-fat diet (HF group) for 6 weeks (n = 20/group). Following this, Mel was administered (10 mg/kg/day) for 8 weeks (n = 10/group), resulting in four groups: C, CMel, HF, and HFMel. The HF group developed obesity. HFMel displayed reduced fat pad size, lower plasma insulin, and improved glucose tolerance and insulin resistance compared to HF. In ovarian WAT (oWAT), HFMel versus HF showed reduced pro-inflammatory markers, less endoplasmic reticulum (ER) stress, and smaller adipocyte size. In subcutaneous WAT (sWAT), HFMel versus HF demonstrated increased adipocyte multiloculation, higher uncoupling protein-1 expression, and elevated thermogenic gene expression. Principal component analysis of gene expressions in oWAT and sWAT revealed significant differences: in oWAT, ER stress and inflammation markers were linked to the HF group, while HFMel and CMel clustered together, indicating a beneficial Mel effect. In sWAT, HFMel and CMel clustered on the opposite side of HF, which is associated with thermogenic gene expressions. In conclusion, the findings demonstrate that Mel supplementation in obese female mice, even when maintained on an HF diet, effectively modulated weight gain and reduced ovarian and subcutaneous fat accumulation. Mel supplementation positively influenced insulin resistance, inflammation, and ER stress while promoting thermogenesis in WAT in obese female mice.

Microbial melatonin metabolism in the human intestine as a therapeutic target for dysbiosis and rhythm disorders

Melatonin (MT) (N-acetyl-5-methoxytryptamine) is an indoleamine recognized primarily for its crucial role in regulating sleep through circadian rhythm modulation in humans and animals. Beyond its association with the pineal gland, it is synthesized in various tissues, functioning as a hormone, tissue factor, autocoid, paracoid, and antioxidant, impacting multiple organ systems, including the gut-brain axis. However, the mechanisms of extra-pineal MT production and its role in microbiota-host interactions remain less understood. This review provides a comprehensive overview of MT, including its production, actions sites, metabolic pathways, and implications for human health. The gastrointestinal tract is highlighted as an additional source of MT, with an examination of its effects on the intestinal microbiota. This review explores whether the microbiota contributes to MT in the intestine, its relationship to food intake, and the implications for human health. Due to its impacts on the intestinal microbiota, MT may be a valuable therapeutic agent for various dysbiosis-associated conditions. Moreover, due to its influence on intestinal MT levels, the microbiota may be a possible therapeutic target for treating health disorders related to circadian rhythm dysregulation.

Melatonin as an adjunctive therapy in cardiovascular disease management

Melatonin, N-acetyl-5-methoxytryptamine, is a neuroendocrine hormone secreted by the pineal gland. This pleiotropic indoleamine possesses amphiphilic properties, allowing it to penetrate most biological barriers and exert its effects at the subcellular level. Importantly, melatonin also plays a crucial role in regulating the body's response to circadian rhythms, adapting to internal and external environmental cues. Melatonin functions as a powerful antioxidant and free radical scavenger, protecting cells from oxidative damage. Its diverse physiological roles include maintaining the functional integrity of endothelial cells, thereby preventing atherosclerosis, a major contributor to cardiovascular disease. Additionally, melatonin exhibits antioxidant and free radical scavenging properties, potentially improving metabolic disorders. These combined effects suggest a unique adjunctive therapeutic potential for melatonin in treating cardiovascular diseases. This review aims to explore the mechanisms by which melatonin interacts with the cardiovascular system and investigates its potential use as an adjunctive therapeutic agent in managing cardiovascular disease.

Melatonin supplementation in obese mothers reduces hypothalamic inflammation and enhances thermogenesis in mice progeny

Maternal obesity might induce obesity and metabolic alterations in the progeny. The study aimed to determine the effect of supplementing obese mothers with Mel (Mel) on thermogenesis and inflammation. C57BL/6 female mice (mothers) were fed from weaning to 12 weeks control diet (C, 17% kJ as fat) or a high-fat diet (HF, 49% kJ as fat) and then matted with male mice fed the control diet. Melatonin (10 mg/kg daily) was supplemented to mothers during gestation and lactation, forming the groups C, CMel, HF, and HFMel (n = 10/group). Twelve-week male offspring were studied (plasma biochemistry, immunohistochemistry, protein, and gene expressions at the hypothalamus - Hyp, subcutaneous white adipose tissue - sWAT, and interscapular brown adipose tissue - iBAT). Comparing HFMel vs. HF offspring, fat deposits and plasmatic proinflammatory markers decreased. Also, HFMel showed decreased Hyp proinflammatory markers and neuropeptide Y (anabolic) expression but improved proopiomelanocortin (catabolic) expression. Besides, HFMel sWAT adipocytes changed to a beige phenotype with-beta-3 adrenergic receptor and uncoupling protein-1 activation, concomitant with browning genes activation, triggering the iBAT thermogenic activity. In conclusion, compelling evidence indicated the beneficial effects of supplementing obese mothers with Mel on the health of their mature male offspring. Mel led to sWAT browning-related gene enhancement, increased iBAT thermogenis, and mitigated hypothalamic inflammation. Also, principal component analysis of the data significantly separated the untreated obese mother progeny from the progeny of treated obese mothers. If confirmed in humans, the findings encourage a future guideline recommending Mel supplementation during pregnancy and breastfeeding.

Chrono-Endocrinology in Clinical Practice: A Journey from Pathophysiological to Therapeutic Aspects

This review was aimed at collecting the knowledge on the pathophysiological and clinical aspects of endocrine rhythms and their implications in clinical practice, derived from the published literature and from some personal experiences on this topic. We chose to review, according to the PRISMA guidelines, the results of original and observational studies, reviews, meta-analyses and case reports published up to March 2024. Thus, after summarizing the general aspects of biological rhythms, we will describe the characteristics of several endocrine rhythms and the consequences of their disruption, paying particular attention to the implications in clinical practice. Rhythmic endocrine secretions, like other physiological rhythms, are genetically determined and regulated by a central hypothalamic CLOCK located in the suprachiasmatic nucleus, which links the timing of the rhythms to independent clocks, in a hierarchical organization for the regulation of physiology and behavior. However, some environmental factors, such as daily cycles of light/darkness, sleep/wake, and timing of food intake, may influence the rhythm characteristics. Endocrine rhythms are involved in important physiological processes and their disruption may cause several disorders and also cancer. Thus, it is very important to prevent disruptions of endocrine rhythms and to restore a previously altered rhythm by an early corrective chronotherapy.

Therapeutic potential of adiponectin in prediabetes: strategies, challenges, and future directions

Adiponectin, an adipose-derived hormone, plays a pivotal role in glucose regulation and lipid metabolism, with a decrease in circulating adiponectin levels being linked to insulin resistance and prediabetes. This review examines the therapeutic potential of adiponectin in managing prediabetes, elucidating on multiple aspects including its role in glucose and lipid metabolism, influence on insulin sensitivity, and anti-inflammatory properties. Moreover, the paper highlights the latest strategies to augment adiponectin levels, such as gene therapy, pharmacological interventions, dietary modifications, and lifestyle changes. It also addresses the challenges encountered in translating preclinical findings into clinical practice, primarily related to drug delivery, safety, and efficacy. Lastly, the review proposes future directions, underlining the need for large-scale human trials, novel adiponectin analogs, and personalized treatment strategies to harness adiponectin's full therapeutic potential in preventing the transition from prediabetes to diabetes.

Tryptophan Metabolism in Obesity: The Indoleamine 2,3-Dioxygenase-1 Activity and Therapeutic Options

Obesity activates both innate and adaptive immune responses in adipose tissue. Adipose tissue macrophages are functional antigen-presenting cells that promote the proliferation of interferon-gamma (IFN-γ)-producing cluster of differentiation (CD)4+ T cells in adipose tissue of obese subjects. The increased formation of neopterin and degradation of tryptophan may result in decreased T-cell responsiveness and lead to immunodeficiency. The activity of inducible indoleamine 2,3-dioxygenase-1 (IDO1) plays a major role in pro-inflammatory, IFN-γ-dominated settings. The expression of several kynurenine pathway enzyme genes is significantly increased in obesity. IDO1 in obesity shifts tryptophan metabolism from serotonin and melatonin synthesis to the formation of kynurenines and increases the ratio of kynurenine to tryptophan as well as with neopterin production. Reduction in serotonin (5-hydroxytryptamine; 5-HT) production provokes satiety dysregulation that leads to increased caloric uptake and obesity. According to the monoamine-deficiency hypothesis, a deficiency of cerebral serotonin is involved in neuropsychiatric symptomatology of depression, mania, and psychosis. Indeed, bipolar disorder (BD) and related cognitive deficits are accompanied by a higher prevalence of overweight and obesity. Furthermore, the accumulation of amyloid-β in Alzheimer's disease brains has several toxic effects as well as IDO induction. Hence, abdominal obesity is associated with vascular endothelial dysfunction. kynurenines and their ratios are prognostic parameters in coronary artery disease. Increased kynurenine/tryptophan ratio correlates with increased intima-media thickness and represents advanced atherosclerosis. However, after bariatric surgery, weight reduction does not lead to the normalization of IDO1 activity and atherosclerosis. IDO1 is involved in the mechanisms of immune tolerance and in the concept of tumor immuno-editing process in cancer development. Serum IDO1 activity is still used as a parameter in cancer development and growth. IDO-producing tumors show a high total IDO immunostaining score, and thus, using IDO inhibitors, such as Epacadostat, Navoximod, and L isomer of 1-methyl-tryptophan, seems an important modality for cancer treatment. There is an inverse correlation between serum folate concentration and body mass index, thus folate deficiency leads to hyperhomocysteinemia-induced oxidative stress. Immune checkpoint blockade targeting cytotoxic T-lymphocyte-associated protein-4 synergizes with imatinib, which is an inhibitor of mitochondrial folate-mediated one-carbon (1C) metabolism. Antitumor effects of imatinib are enhanced by increasing T-cell effector function in the presence of IDO inhibition. Combining IDO targeting with chemotherapy, radiotherapy and/or immunotherapy, may be an effective tool against a wide range of malignancies. However, there are some controversial results regarding the efficacy of IDO1 inhibitors in cancer treatment.

Misalignment of Circadian Rhythms in Diet-Induced Obesity

The biological clocks of the circadian timing system coordinate cellular and physiological processes and synchronize them with daily cycles. While the central clock in the suprachiasmatic nucleus (SCN) is mainly synchronized by the light/dark cycles, the peripheral clocks react to other stimuli, including the feeding/fasting state, nutrients, sleep-wake cycles, and physical activity. During the disruption of circadian rhythms due to genetic mutations or social and occupational obligations, incorrect arrangement between the internal clock system and environmental rhythms leads to the development of obesity. Desynchronization between the central and peripheral clocks by altered timing of food intake and diet composition leads to uncoupling of the peripheral clocks from the central pacemaker and to the development of metabolic disorders. The strong coupling of the SCN to the light-dark cycle creates a situation of misalignment when food is ingested during the "wrong" time of day. Food-anticipatory activity is mediated by a self-sustained circadian timing, and its principal component is a food-entrainable oscillator. Modifying the time of feeding alone greatly affects body weight, whereas ketogenic diet (KD) influences circadian biology, through the modulation of clock gene expression. Night-eating behavior is one of the causes of circadian disruption, and night eaters have compulsive and uncontrolled eating with severe obesity. By contrast, time-restricted eating (TRE) restores circadian rhythms through maintaining an appropriate daily rhythm of the eating-fasting cycle. The hypothalamus has a crucial role in the regulation of energy balance rather than food intake. While circadian locomotor output cycles kaput (CLOCK) expression levels increase with high-fat diet-induced obesity, peroxisome proliferator-activated receptor-alpha (PPARα) increases the transcriptional level of brain and muscle aryl hydrocarbon receptor nuclear translocator (ARNT)-like 1 (BMAL1) in obese subjects. In this context, effective timing of chronotherapies aiming to correct SCN-driven rhythms depends on an accurate assessment of the SCN phase. In fact, in a multi-oscillator system, local rhythmicity and its disruption reflects the disruption of either local clocks or central clocks, thus imposing rhythmicity on those local tissues, whereas misalignment of peripheral oscillators is due to exosome-based intercellular communication.Consequently, disruption of clock genes results in dyslipidemia, insulin resistance, and obesity, while light exposure during the daytime, food intake during the daytime, and sleeping during the biological night promote circadian alignment between the central and peripheral clocks. Thus, shift work is associated with an increased risk of obesity, diabetes, and cardiovascular diseases because of unusual eating times as well as unusual light exposure and disruption of the circadian rhythm.

Protective Effects of Melatonin in High-Fat Diet-Induced Hepatic Steatosis via Decreased Intestinal Lipid Absorption and Hepatic Cholesterol Synthesis

BACKGRUOUND

The preventative effect of melatonin on the development of obesity and the progression of fatty liver under a high-fat diet (HFD) has been well elucidated through previous studies. We investigated the mechanism behind this effect regarding cholesterol biosynthesis and regulation of cholesterol levels.

METHODS

Mice were divided into three groups: normal chow diet (NCD); HFD; and HFD and melatonin administration group (HFD+M). We assessed the serum lipid profile, mRNA expression levels of proteins involved in cholesterol synthesis and reabsorption in the liver and nutrient transporters in the intestines, and cytokine levels. Additionally, an in vitro experiment using HepG2 cells was performed.

RESULTS

Expression of hepatic sterol regulatory element-binding protein 2 (SREBP-2), 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGCR), and low-density lipoprotein receptor (LDLR) demonstrated that melatonin administration significantly reduces hepatic cholesterol synthesis in mice fed an HFD. Expression of intestinal sodium-glucose transporter 1 (SGLT1), glucose transporter 2 (GLUT2), GLUT5, and Niemann-pick C1-like 1 (NPC1L1) demonstrated that melatonin administration significantly reduces intestinal carbohydrate and lipid absorption in mice fed an HFD. There were no differences in local and circulatory inflammatory cytokine levels among the NCD, HFD, and HFD+M group. HepG2 cells stimulated with palmitate showed reduced levels of SREBP, LDLR, and HMGCR indicating these results are due to the direct mechanistic effect of melatonin on hepatocytes.

CONCLUSION

Collectively, these data indicate the mechanism behind the protective effects of melatonin from weight gain and liver steatosis under HFD is through a reduction in intestinal caloric absorption and hepatic cholesterol synthesis highlighting its potential in the treatment of obesity and fatty liver disease.

Effects of Melatonin Supplementation on Lipid Metabolism and Body Fat Accumulation in Ovariectomized Rats

Postmenopausal obesity is a rising problem. Melatonin (Mel) is a hormone secreted by the pineal gland that regulates the circadian rhythms and improves obesity. In this experiment, ovariectomized (OVX) rats were used as a menopause model to explore the effects of Mel supplementation on lipid metabolism, body fat accumulation, and obesity. Nine-week-old female rats underwent an OVX surgery and were assigned to the following groups: control group (C), low-dose group (L, 10 mg/kg body weight (BW) Mel), medium-dose group (M, 20 mg/kg BW Mel), and high-dose group (H, 50 mg/kg BW Mel), administered by gavage for 8 weeks. The results showed that the OVX rats supplemented with low, medium, and high doses of Mel for 8 weeks exhibited reduced BW gain, perirenal fat mass, and gonads fat mass, and an increased serum irisin level. Low and high doses of Mel induced brite/beige adipocytes in the white adipose tissues. In addition, the messenger RNA levels of the fatty acid synthesis enzymes were significantly reduced after the high-dose Mel supplementation. Thus, Mel can reduce the hepatic fatty acid synthesis and promote the browning of white adipose tissues through irisin; thereby, improving obesity and body fat accumulation in OVX rats.

Mitochondria: It is all about energy

Mitochondria play a key role in both health and disease. Their function is not limited to energy production but serves multiple mechanisms varying from iron and calcium homeostasis to the production of hormones and neurotransmitters, such as melatonin. They enable and influence communication at all physical levels through interaction with other organelles, the nucleus, and the outside environment. The literature suggests crosstalk mechanisms between mitochondria and circadian clocks, the gut microbiota, and the immune system. They might even be the hub supporting and integrating activity across all these domains. Hence, they might be the (missing) link in both health and disease. Mitochondrial dysfunction is related to metabolic syndrome, neuronal diseases, cancer, cardiovascular and infectious diseases, and inflammatory disorders. In this regard, diseases such as cancer, Alzheimer's, Parkinson's, amyotrophic lateral sclerosis (ALS), chronic fatigue syndrome (CFS), and chronic pain are discussed. This review focuses on understanding the mitochondrial mechanisms of action that allow for the maintenance of mitochondrial health and the pathways toward dysregulated mechanisms. Although mitochondria have allowed us to adapt to changes over the course of evolution, in turn, evolution has shaped mitochondria. Each evolution-based intervention influences mitochondria in its own way. The use of physiological stress triggers tolerance to the stressor, achieving adaptability and resistance. This review describes strategies that could recover mitochondrial functioning in multiple diseases, providing a comprehensive, root-cause-focused, integrative approach to recovering health and treating people suffering from chronic diseases.

Nano-melatonin and-histidine modulate adipokines and neurotransmitters to improve cognition in HFD-fed rats: A formula to study

The established correlation between obesity and cognitive impairment portrays pharmacological products aimed at both disorders as an important therapeutic advance. Modulation of dysregulated adipokines and neurotransmitters is hence a critical aspect of the assessment of in-use drugs. At the cellular level, repairments in brain barrier integrity and cognitive flexibility are the main checkpoints. The aim of this study was to investigate whether melatonin and histidine, alone or in combination, could produce weight loss, meanwhile improve the cognitive processes. In this study, obese rat model was established by feeding high fat diet (HFD) composed of 25% fats (soybean oil) for 8 weeks, accompanied by melatonin (10 mg/kg), histidine (780 mg/kg), and combination of both in conventional form and nanoform. At the end of the study, adiposity hormones, neuronal monoamines and amino acids, brain derived neurotrophic factor (BDNF) and zonula occluden-1 (ZO-1) were assessed. HFD feeding resulted in significant weight gain and poor performance on cognitive test. Coadministration of histidine in the nanoform increased the level of ZO-1; an indicator of improving the brain barrier integrity, along with adjusting the adipokines and neurotransmitters levels, which had a positive impact on learning tasks. Cotreatment with melatonin resulted in an increase in the level of BDNF, marking ameliorated synaptic anomalies and learning disabilities, while reducing weight gain. On the other hand, the combination of melatonin and histidine reinstated the synaptic plasticity as well as brain barrier junctions, as demonstrated by increased levels of BDNF and ZO-1, positively affecting weight loss and the intellectual function.

Is time-restricted eating (8/16) beneficial for body weight and metabolism of obese and overweight adults? A systematic review and meta-analysis of randomized controlled trials

Time-restricted eating (TRE) is a new therapeutic strategy for the management of weight loss and dysmetabolic diseases. At present, TRE (8/16, 8 h eating:16 h fasting) is the most common form of TRE. Therefore, this meta-analysis included randomized controlled trials (RCTs) on TRE (8/16) in overweight and obese adults to determine its impact on body weight and metabolism. Articles reviewed from PubMed, Ovid MEDLINE, Embase, and Cochrane Central Register for the relevant RCTs that compared TRE (8/16) to non-TRE in overweight and obese adults. Eight RCTs were included in this meta-analysis. Participants following TRE (8/16) showed significant body weight reduction (mean difference [MD]: -1.48 kg, 95% confidence interval [CI]: -2.53 to -0.44) and fat mass reduction (MD: -1.09 kg, 95% CI: -1.55 to -0.63). There was no significant difference in lean mass change with TRE intervention (MD: -0.48 kg, 95% CI: -1.02 to 0.05, p = .08, I 2 = 41%). The energy restriction and early TRE (eTRE) subgroups resulted in greater weight loss. TRE (8/16) showed beneficial effects on the homeostatic model assessment of insulin resistance (HOMA-IR, MD: -0.32, 95% CI: -0.59 to -0.06), but had no significant effect on other parameters of glucose metabolism and lipid profiles. In conclusion, TRE (8/16), especially eTRE, or in combination with caloric intake restriction, is a potential therapeutic strategy for weight control in overweight and obese adults. TRE (8/16) also reduced HOMA-IR; therefore, it may have a positive effect on glucose metabolism.

Evaluation of Selected Parameters of Oxidative Stress and Adipokine Levels in Hospitalized Older Patients with Diverse Nutritional Status

Malnutrition is classified as one of the Giant Geriatric Syndromes. It carries serious consequences, such as sarcopenia or depression, which lead to functional disability. The main objective of this study was to identify parameters of oxidative stress and adipokines, which may be potential biomarkers of malnutrition in hospitalized older patients. During the study, selected parameters were determined in 137 senile patients, taking into account their nutritional status determined according to the Mini Nutritional Assessment (MNA), as well as an additional tool, namely the Geriatric Nutritional Risk Index (GNRI). Leptin and resistin were determined as the parameters with statistically significant differences between the patients classified according to the MNA. This phenomenon was confirmed using the GNRI classification. However, additional parameters for which differences were observed include the oxidized low-density lipoprotein level and activity of glutathione peroxidase. In conclusion, the determination of the mentioned markers in hospitalized senile patients as an adjunct to the routine assessment of nutritional status might be suggested to identify the early risk of malnutrition so that a personalized nutritional therapy can be implemented as early as possible.

Inflammaging: Implications in Sarcopenia

In a world in which life expectancy is increasing, understanding and promoting healthy aging becomes a contemporary demand. In the elderly, a sterile, chronic and low-grade systemic inflammation known as "inflammaging" is linked with many age-associated diseases. Considering sarcopenia as a loss of strength and mass of skeletal muscle related to aging, correlations between these two terms have been proposed. Better knowledge of the immune system players in skeletal muscle would help to elucidate their implications in sarcopenia. Characterizing the activators of damage sensors and the downstream effectors explains the inference with skeletal muscle performance. Sarcopenia has also been linked to chronic diseases such as diabetes, metabolic syndrome and obesity. Implications of inflammatory signals from these diseases negatively affect skeletal muscle. Autophagic mechanisms are closely related with the inflammasome, as autophagy eliminates stress signaling sent by damage organelles, but also acts with an immunomodulatory function affecting immune cells and cytokine release. The use of melatonin, an antioxidant, ROS scavenger and immune and autophagy modulator, or senotherapeutic compounds targeting senescent cells could represent strategies to counteract inflammation. This review aims to present the many factors regulating skeletal muscle inflammaging and their major implications in order to understand the molecular mechanisms involved in sarcopenia.

The relationships between social media exposure, food craving, cognitive impulsivity and cognitive restraint

BACKGROUND

Young adults are increasingly exposed to social media and their image/video-based activities. They use these platforms to share images, videos and advice in different fields like food and nutrition with: recipe ideas, nutritional opinions or specific diets. Along with the rise of digital technologies, the prevalence of eating disorders in young adults continues to grow. The present study analyzes the psychological and eating processes through which exposure to social media may lead to the development of food craving and problematic eating behaviors.

METHODS

A total of 103 young adult men (n = 15) and women (n = 88) answered questionnaires measuring their impulsivity (Barratt Impulsiveness Scale), eating habits (Three-Factor Eating Questionnaire), food craving (Food Cravings Questionnaire-Trait-reduced), and time exposure to social media.

RESULTS

The results showed two significant serial mediations. We found a correlational link between time exposure to social media and food craving scores. This positive relation is indirectly mediated by cognitive impulsivity. We also found a positive correlation between cognitive impulsivity and food craving scores that was mediated by cognitive restraint.

CONCLUSION

A better understanding of the existing links between social media, food craving and eating behaviors such as cognitive restraint could help researchers and clinicians to better guide young adults in their use and appropriation of social media food contents.

Melatonin Alleviates Venous Dysfunction in a Mouse Model of Iliac Vein Occlusion

The iliac vein can be severely stenosed and occluded due to thrombosis, tumor compression, or an anatomical abnormality. Such occlusion could result in limb swelling, venous claudication, and persistent leg ulcers. Its devastating sequelae heavily impact patients lifestyles and the social economy. Due to a lack of a stable and easy-to-operate iliac vein occlusion (IVO) model, its underlying molecular mechanism and pathophysiological process has not been completely understood. Melatonin (MLT) plays a critical role in anti-inflammation, but the potential protective effect of melatonin on venous dysfunction induced by IVO has not been revealed. In this study, a mouse model of IVO was established to study the effects of MLT on injured veins. The results of laser speckle images and Evans blue showed that MLT inhibited venous permeability in an IVO mouse model. Furthermore, MLT suppressed inflammation of surrounding tissues close to the affected vein by inhibiting the mRNA levels of TNF-α, IL-1α, and MCP-1. In addition, endothelial injury was inhibited by MLT using zonula occludens protein-1 (ZO-1) staining. Taken together, we elucidated the therapeutic effect of MLT on vascular dysfunction induced by IVO, mainly by inhibiting the TNF-α, IL-1α, and MCP-1 mRNA levels, improving endothelial function, and inhibiting vascular leakage.

Metabolic syndrome and underlying genetic determinants-A systematic review

The metabolic syndrome is a cluster of heritable and related traits which has been associated with a range of pathophysiological factors including dyslipidaemia, abdominal obesity, increased fasting plasma glucose (FPG) and hypertension. The documented genetic basis of the metabolic syndrome include several chromosomal positions, numerous candidate gene-associated polymorphisms, different genetic variants, which are linked to the syndrome either as a trait or entities mainly linked to metabolic process. Additionally, the latest findings related to the contribution of epigenetic mechanisms, microRNAs, sporadic variants, non-coding RNAs, and assessing the role of genes in molecular systems has enhanced our understanding of the syndrome. Considerable work has been done to understand the underlying disease mechanisms by elucidating its genetic etiology. Nonetheless, a common shared genetic cause has not been established to clarify the coexistence of their components and further investigation is required. While mostly neglected and rarely known, hereditary predisposition needs to be studied, including with the current defective phenotypic condition descriptions. Metabolic syndrome is a multi-faceted characteristic with abundant properties and the condition can arise from interactions between environmental variables such as physical inactivity, caloric obesity and genetic susceptibility. Although there is support for genetic determinants from family and twin research, there is still no recognised genomic DNA marker for genetic association and linkages with quite a long way off potential for clinical application. In the present review efforts have been made to through light on the various genetic determinants with large effects that underlie with the association of these traits to this syndrome. The heterogeneity and multifactorial heritability of MetS, however, has been a challenge towards understanding the factors underlying the association of these traits.

Randomized controlled trial for time-restricted eating in healthy volunteers without obesity

Time-restricted feeding (TRF) improves metabolic health. Both early TRF (eTRF, food intake restricted to the early part of the day) and mid-day TRF (mTRF, food intake restricted to the middle of the day) have been shown to have metabolic benefits. However, the two regimens have yet to be thoroughly compared. We conducted a five-week randomized trial to compare the effects of the two TRF regimens in healthy individuals without obesity (ChiCTR2000029797). The trial has completed. Ninety participants were randomized to eTRF (n=30), mTRF (n=30), or control groups (n=30) using a computer-based random-number generator. Eighty-two participants completed the entire five-week trial and were analyzed (28 in eTRF, 26 in mTRF, 28 in control groups). The primary outcome was the change in insulin resistance. Researchers who assessed the outcomes were blinded to group assignment, but participants and care givers were not. Here we show that eTRF was more effective than mTRF at improving insulin sensitivity. Furthermore, eTRF, but not mTRF, improved fasting glucose, reduced total body mass and adiposity, ameliorated inflammation, and increased gut microbial diversity. No serious adverse events were reported during the trial. In conclusion, eTRF showed greater benefits for insulin resistance and related metabolic parameters compared with mTRF. Clinical Trial Registration URL: http://www.chictr.org.cn/showproj.aspx?proj=49406.

Time-restricted eating, both early (eTRF) and mid-day (mTRF), have been shown to have metabolic benefits. Here the authors report a randomized controlled trial to compare the effects of eTRF and mTRF in healthy volunteers without obesity, and find that eTRF is more effective in improving the primary outcome insulin sensitivity.

[Melatonin status in obese patients with ovarian dysfunction at reproductive age]

BACKGROUND

Melatonin is the main hormone of the pineal gland. By regulating circadian rhythms and being an immune regulator and antioxidant, this hormone takes part in the work of the ovaries: its high concentrations block apoptosis and neutralize reactive oxygen species involved in folliculogenesis, ovulation, egg maturation and corpus luteum formation.

AIM

To study melatonin status and its relationship with menstrual dysfunction and sleep disorders in obese women of reproductive age.

MATERIALS AND METHODS

In a one-stage comparative study, women 18-35 years old took part: 30 patients with obesity and menstrual disorders of an inorganic nature and 30 healthy women in the comparison group with normal weight and regular menstrual cycle. All participants underwent a questionnaire to identify somnological disorders, and the level of melatonin in saliva and 6-sulfatoxymelatonin in urine was also investigated.

RESULTS

In the group of patients with obesity (n=30), various sleep disorders were encountered in 47% of cases (p=0.003), including more often obstructive sleep apnea syndrome was recorded (30% of cases), and a correlation was found between the indicators of the questionnaire survey of subjective sleep characteristics and body mass index of patients (r=0.450, p=0.030) compared with a group of healthy women with normal weight (n=30). In the main group, the level of melatonin in saliva was statistically significantly lower than in the control: median 12.6 pg / ml and 25.5 pg / ml, respectively (p=0.008), the same pattern was recorded for 6-sulfatoxymelatonin: 14, 72 pg / ml and 31.12 pg / ml, respectively.

CONCLUSION

Patients with obesity and menstrual dysfunction are more likely to suffer from various sleep disorders and have lower levels of melatonin in saliva and 6-sulfatoxymelatonin in urine.

Protective Effects of Melatonin against Obesity-Induced by Leptin Resistance

Consumption of an exceedingly high-fat diet with irregular eating and sleeping habits is typical in the current sedentary lifestyle, leading to chronic diseases like obesity and diabetes mellitus. Leptin is a primary appetite-regulating hormone that binds to its receptors in the hypothalamic cell membrane and regulates downstream appetite-regulating neurons NPY/AgRp and POMC in the hypothalamus. Based on the fat content of the adipose tissue, leptin is secreted, and excess accumulation of fat in adipose tissue stimulates the abnormal secretion of leptin. The secreted leptin circulating in the bloodstream uses its transporters to cross the blood-brain barrier (BBB) and reach the CSF. There is a saturation limit for leptin bound to its transporters to cross the BBB, and increased leptin secretion in adipose tissue has a defect in its transport across the BBB. Leptin resistance is due to excess leptin, a saturation of its transporters, and deficiency in either the receptor level or signalling in the hypothalamus. Leptin resistance leads to obesity due to excess food intake and less energy expenditure. Normal leptin secretion follows a rhythm, and alteration in the lifestyle leads to hormonal imbalances and increases ROS generation leading to oxidative stress. The sleep disturbance causes obesity with increased lipid accumulation in adipose tissue. Melatonin is the master regulator of the sleep-wake cycle secreted by the pineal gland during the night. It is a potent antioxidant with anti-inflammatory properties. Melatonin is secreted in a pattern called the circadian rhythm in humans as well. Research indicates that melatonin plays a vital role in hormonal regulation and energy metabolism, including leptin signalling and secretion. Studying the role of melatonin in leptin regulation will help us combat the pathologies of obesity caused by leptin resistance.

Kidney Damage Caused by Obesity and Its Feasible Treatment Drugs

The rapid growth of obesity worldwide has made it a major health problem, while the dramatic increase in the prevalence of obesity has had a significant impact on the magnitude of chronic kidney disease (CKD), especially in developing countries. A vast amount of researchers have reported a strong relationship between obesity and chronic kidney disease, and obesity can serve as an independent risk factor for kidney disease. The histological changes of kidneys in obesity-induced renal injury include glomerular or tubular hypertrophy, focal segmental glomerulosclerosis or bulbous sclerosis. Furthermore, inflammation, renal hemodynamic changes, insulin resistance and lipid metabolism disorders are all involved in the development and progression of obesity-induced nephropathy. However, there is no targeted treatment for obesity-related kidney disease. In this review, RAS inhibitors, SGLT2 inhibitors and melatonin would be presented to treat obesity-induced kidney injury. Furthermore, we concluded that melatonin can protect the kidney damage caused by obesity by inhibiting inflammation and oxidative stress, revealing its therapeutic potential.

MELATONIN IMPROVES SPLEEN HISTOPHYSIOLOGY OF RATS WITH DIET-INDUCED OBESITY: CHRONOTHERAPY APPROACH

One of the most commoncharacteristics of obesity is the development of a systemic low-grade proinflammatory state in the entire body, including the immune organs. Spleen enlargement during diet-induced obesity contributes to the development of chronic inflammation. Melatonin due to immunomodulatory, antioxidant, and systemic metabolic rolesis proposed to be an effective candidate for anti-obesity therapy. As immune systems demonstrate pronounced circadian rhythmicity and immune cells have different types of melatonin receptors, a chronotherapeutic approach might be used to choose the most effective regimes of melatonin administration for the correction of obesity-provoked damage to the spleen. Thus, the main goal of our research was the analysis of the rats' spleen histophysiology during the development of high-calorie diet-inducedobesity (HCD) after administering melatonin daily at different times (morning or evening). Melatonin was administered by gavage for 7 weeks in the dose of 30 mg/kg 1 h before lights-off (HCD ZT11, M ZT11, evening), or 1 h after lights-on (HCD ZT01, M ZT01, morning). For assessment of the morpho-functional state of the spleen,the histopathological evaluation of red and white pulp in different zones of lymphoid follicles was implemented. It was observed that obesity development wasaccompaniedbyhyperemia and vessel dilatation in the red pulp; while in the white pulp notable deformation of germinal centers and destroyed borders between zones of lymphoid follicles were noticed.The HCD group demonstrated a decrease inthe relative amount of the white pulp, the crosssectional area of germinal centers, and the cross-sectional area of the marginal zone; whilethe increased relative amount of red pulp and marginal zone/germinal centers ratiowere detected compared with control. Melatonin administration to obese rats increases the relative amount of the white pulp (HCD ZT11 group), the cross-sectional area of germinal centers (HCD ZT01 and HCD ZT11 groups), and the cross-sectional area of the marginal zone (HCD ZT11 group), and decreasesmarginal zone/germinal centers ratio (HCD ZT01 group) in comparison with the HCD group.Also,it was demonstrated that a choice between the morning or evening regimes of the melatonin treatment did not affect the histophysiology of the spleen in rats receivingthe standard diet (M ZT01 and M ZT11 groups). These results indicate that melatonin can be considered to be a powerful potential therapeutic agent for the amelioration of obesity-induced changes in the spleen.

Therapeutic Target Analysis and Molecular Mechanism of Melatonin - Treated Leptin Resistance Induced Obesity: A Systematic Study of Network Pharmacology

BACKGROUND

Obesity is a medical problem with an increased risk for other metabolic disorders like diabetes, heart problem, arthritis, etc. Leptin is an adipose tissue-derived hormone responsible for food intake, energy expenditure, etc., and leptin resistance is one of the significant causes of obesity. Excess leptin secretion by poor diet habits and impaired hypothalamic leptin signaling leads to LR. Melatonin a sleep hormone; also possess antioxidant and anti-inflammatory properties. The melatonin can attenuate the complications of obesity by regulating its targets towards LR induced obesity.

AIM

The aim of this study includes molecular pathway and network analysis by using a systems pharmacology approach to identify a potential therapeutic mechanism of melatonin on leptin resistance-induced obesity.

METHODS

The bioinformatic methods are used to find therapeutic targets of melatonin in the treatment of leptin resistance-induced obesity. It includes target gene identification using public databases, Gene ontology, and KEGG pathway enrichment by 'ClusterProfiler' using the R language, network analysis by Cytoscape, and molecular Docking by Autodock.

RESULTS

We obtained the common top 33 potential therapeutic targets of melatonin and LR-induced obesity from the total melatonin targets 254 and common LR obesity targets 212 using the data screening method. They are involved in biological processes related to sleep and obesity, including the cellular response to external stimulus, chemical stress, and autophagy. From a total of 180 enriched pathways, we took the top ten pathways for further analysis, including lipid and atherosclerosis, endocrine, and AGE-RAGE signaling pathway in diabetic complications. The top 10 pathways interacted with the common 33 genes and created two functional modules. Using Cytoscape network analysis, the top ten hub genes (TP53, AKT1, MAPK3, PTGS2, TNF, IL6, MAPK1, ERBB2, IL1B, MTOR) were identified by the MCC algorithm of the CytoHubba plugin. From a wide range of pathway classes, melatonin can reduce LR-induced obesity risks by regulating the major six classes. It includes signal transduction, endocrine system, endocrine and metabolic disease, environmental adaptation, drug resistance antineoplastic, and cardiovascular disease.

CONCLUSION

The pharmacological mechanism of action in this study shows the ten therapeutic targets of melatonin in LR-induced obesity.

Mechanisms of Melatonin in Obesity: A Review

Obesity and its complications have become a prominent global public health problem that severely threatens human health. Melatonin, originally known as an effective antioxidant, is an endogenous hormone found throughout the body that serves various physiological functions. In recent decades, increasing attention has been paid to its unique function in regulating energy metabolism, especially in glucose and lipid metabolism. Accumulating evidence has established the relationship between melatonin and obesity; nevertheless, not all preclinical and clinical evidence indicates the anti-obesity effect of melatonin, which makes it remain to conclude the clinical effect of melatonin in the fight against obesity. In this review, we have summarized the current knowledge of melatonin in regulating obesity-related symptoms, with emphasis on its underlying mechanisms. The role of melatonin in regulating the lipid profile, adipose tissue, oxidative stress, and inflammation, as well as the interactions of melatonin with the circadian rhythm, gut microbiota, sleep disorder, as well as the α7nAChR, the opioidergic system, and exosomes, make melatonin a promising agent to open new avenues in the intervention of obesity.

Protective role of melatonin against adipose-hepatic metabolic comorbidities in experimentally induced obese rat model

Background

Adipose and hepatic metabolic dysfunctions are critical comorbidities that also aggravate insulin resistance in obese individuals. Melatonin is a low-cost agent and previous studies suggest that its use may promote metabolic health. However, its effects on some comorbidities associated with obesity are unknown. Herein, we investigated the hypothesis that melatonin supplementation would attenuate adipose-hepatic metabolic dysfunction in high fat diet (HFD)-induced obesity in male Wistar rats.

Materials and methods

Twenty-four adult male Wistar rats (n = 6/group) were used: Control group received vehicle (normal saline), obese group received 40% high fat diet, melatonin-treated group received 4 mg/kg of melatonin, and obese plus melatonin group received 40% HFD and melatonin. The treatment lasted for 12 weeks.

Results

HFD caused increased food intake, body weight, insulin level, insulin resistance and plasma and liver lipid but decreased adipose lipid. In addition, HFD also increased plasma, adipose and liver malondialdehyde, IL-6, uric acid and decreased Glucose-6-phosphate dehydrogenase, glutathione, nitric oxide and circulating obestatin concentration. However, these deleterious effects except food intake were attenuated when supplemented with melatonin.

Conclusion

Taken together, the present results indicate that HFD exposure causes adipose-hepatic metabolic disturbance in obese animals, which are accompanied by oxidative stress and inflammation. In addition, the present results suggest that melatonin supplementation attenuates adipose-hepatic metabolic dysfunction, accompanying obesity by suppression of oxidative stress/inflammation-dependent mechanism and increasing circulating obestatin.

Effects of Early vs. Late Time-Restricted Eating on Cardiometabolic Health, Inflammation, and Sleep in Overweight and Obese Women: A Study Protocol for the ChronoFast Trial

Background: Time-restricted eating is a promising dietary strategy for weight loss, glucose and lipid metabolism improvements, and overall well-being. However, human studies demonstrated contradictory results for the restriction of food intake to the beginning (early TRE, eTRE) or to the end of the day (late TRE, lTRE) suggesting that more carefully controlled studies are needed.

Objective: The aim of the ChronoFast trial study is to determine whether eTRE or lTRE is a better dietary approach to improve cardiometabolic health upon minimized calorie deficits and nearly stable body weight.

Methods: Here, we present the study protocol of the randomized cross-over ChronoFast clinical trial comparing effects of 2 week eTRE (8:00 to 16:00 h) and lTRE (13:00 to 21:00 h) on insulin sensitivity and other glycemic traits, blood lipids, inflammation, and sleep quality in 30 women with overweight or obesity and increased risk of type 2 diabetes. To ensure timely compliance and unchanged dietary composition, and to minimize possible calorie deficits, real-time monitoring of dietary intake and body weight using a smartphone application, and extensive nutritional counseling are performed. Continuous glucose monitoring, oral glucose tolerance test, 24 h activity tracking, questionnaires, and gene expression analysis in adipose tissue and blood monocytes will be used for assessment of study outcomes.

Discussion: The trial will determine whether eTRE or lTRE is more effective to improve cardiometabolic health, elucidate underlying mechanisms, and contribute to the development of recommendations for medical practice and the wider population.

Clinical Trial Registration:www.ClinicalTrials.gov, Identifier [NCT04351672]

Effectiveness of Intensive Cardiac Rehabilitation in High-Risk Patients with Cardiovascular Disease in Real-World Practice

Structured lifestyle interventions through cardiac rehabilitation (CR) are critical to improving the outcome of patients with cardiovascular disease (CVD) and cardiometabolic risk factors. CR programs' variability in real-world practice may impact CR effects. This study evaluates intensive CR (ICR) and standard CR (SCR) programs for improving cardiometabolic, psychosocial, and clinical outcomes in high-risk CVD patients undergoing guideline-based therapies. Both programs provided lifestyle counseling and the same supervised exercise component. ICR additionally included a specialized plant-based diet, stress management, and social support. Changes in body weight (BW), low-density lipoprotein cholesterol (LDL-C), and exercise capacity (EC) were primary outcomes. A total of 314 patients (101 ICR and 213 SCR, aged 66 ± 13 years, 75% overweight/obese, 90% coronary artery disease, 29% heart failure, 54% non-optimal LDL-C, 43% depressive symptoms) were included. Adherence to ICR was 96% vs. 68% for SCR. Only ICR resulted in a decrease in BW (3.4%), LDL-C (11.3%), other atherogenic lipids, glycated hemoglobin, and systolic blood pressure. Both ICR and SCR increased EC (52.2% and 48.7%, respectively) and improved adiposity indices, diastolic blood pressure, cholesterol intake, depression, and quality of life, but more for ICR. Within 12.6 ± 4.8 months post-CR, major adverse cardiac events were less likely in the ICR than SCR group (11% vs. 17%), especially heart failure hospitalizations (2% vs. 8%). A comprehensive ICR enhanced by a plant-based diet and psychosocial management is feasible and effective for improving the outcomes in high-risk CVD patients in real-world practice.

Melatonin Supplementation and Anthropometric Indices: A Randomized Double-Blind Controlled Clinical Trial

Obesity, as the most common metabolic disorder in the world, is characterized by excess body fat. This study is aimed at determining the effects of melatonin supplementation on body weight, nody mass index (BMI), waist circumference (WC), and body fat mass percentage (BFMP) in people with overweight or obesity. Thirty eight overweight or class-I obese adult individuals were recruited in the study (8 men and 30 women). Participants prescribed a weight-loss diet and then randomly were allocated to melatonin or placebo groups. Participants received either a 3-milligram melatonin or placebo tablet per day for 12 weeks. In order to assess differences at the significance level of 0.05, repeated measure ANOVA and paired t-test were used. According to the results, a significant reduction was found in participants' body weight, WC, and BMI in both groups (p = 0.001). However, for the last six weeks, significant reductions of these parameters were observed only in the melatonin group (p = 0.01). The BFMP of participants in the melatonin group showed a significant reduction at the end of the study compared to the initial measurements (p = 0.008). Nevertheless, the results of the present study alone are not sufficient to conclude on the effects of melatonin consumption on anthropometric indices, and it seems that further studies are required in this regard.

A New Paradigm in the Relationship between Melatonin and Breast Cancer: Gut Microbiota Identified as a Potential Regulatory Agent

In this review we summarize a possible connection between gut microbiota, melatonin production, and breast cancer. An imbalance in gut bacterial population composition (dysbiosis), or changes in the production of melatonin (circadian disruption) alters estrogen levels. On the one hand, this may be due to the bacterial composition of estrobolome, since bacteria with β-glucuronidase activity favour estrogens in a deconjugated state, which may ultimately lead to pathologies, including breast cancer. On the other hand, it has been shown that these changes in intestinal microbiota stimulate the kynurenine pathway, moving tryptophan away from the melatonergic pathway, thereby reducing circulating melatonin levels. Due to the fact that melatonin has antiestrogenic properties, it affects active and inactive estrogen levels. These changes increase the risk of developing breast cancer. Additionally, melatonin stimulates the differentiation of preadipocytes into adipocytes, which have low estrogen levels due to the fact that adipocytes do not express aromatase. Consequently, melatonin also reduces the risk of breast cancer. However, more studies are needed to determine the relationship between microbiota, melatonin, and breast cancer, in addition to clinical trials to confirm the sensitizing effects of melatonin to chemotherapy and radiotherapy, and its ability to ameliorate or prevent the side effects of these therapies.

Exosomes and Melatonin: Where Their Destinies Intersect

Cell-to-cell communication is a broad and complex process associated with regular stimuli to maintain healthy cell interactions. One of the agents capable of cellular communication is known as an exosome, a subset of extracellular vesicles (EVs) released by the cell membrane. The exosome contains a wide range of functional proteins, mRNAs and miRNAs, which have the potential to interact with healthy or diseased cells in the body. On the other hand, melatonin also acts as a cellular communicator, produced and released by the pineal gland in a circadian way and also, non-circadian melatonin is derived from the mitochondria of all normal cells. In addition to exhibiting antioxidant, anti-inflammatory, anti-tumor and anti-aging activities, melatonin has recently been studied by its influence on exosomes. This review summarizes the relationship between exosomes and melatonin in various pathological processes. There is robust evidence that their combination ameliorates inflammation, ischemia-reperfusion injury, hepatic metabolic disturbance, cancer immunosuppression status, degenerative processes like chronic kidney disease, vascular calcification, ageing, ischemic brain injury, neurodegenerative diseases, obesity, colitis, wound healing and even embryonic development. Association of exosomes and melatonin represent a promising therapeutic tool, capable of interfering with basic molecular processes, such as oxidative stress and the inflammatory cascade, which support many pathophysiological aspects of diseases.

Eating Speed, Eating Frequency, and Their Relationships with Diet Quality, Adiposity, and Metabolic Syndrome, or Its Components

Excess body weight is a major global health concern, particularly due to its associated increased health risks. Several strategies have been proposed to prevent overweight and obesity onset. In the past decade, it has been suggested that eating speed/rate and eating frequency might be related to obesity. The main aim of this narrative review was to summarize existing evidence regarding the impact of eating speed/rate and eating frequency on adiposity, metabolic syndrome (MetS), or diet quality (DQ). For this purpose, a literature search of observational and interventional trials was conducted between June and September 2020 in PubMed and Web of Sciences databases, without any data filters and no limitations for publication date. Results suggest that children and adults with a faster eating speed/rate may be associated with a higher risk of developing adiposity, MetS or its components. Furthermore, a higher eating frequency could be associated with diet quality improvement, lower adiposity, and lower risk of developing MetS or its components. Further interventional trials are warranted to clarify the mechanism by which these eating behaviors might have a potential impact on health.

ROR: Nuclear Receptor for Melatonin or Not?

Whether the retinoic acid-related orphan receptor (ROR) is a nuclear receptor of melatonin remains controversial. ROR is inextricably linked to melatonin in terms of its expression, function, and mechanism of action. Additionally, studies have illustrated that melatonin functions analogous to ROR ligands, thereby modulating the transcriptional activity of ROR. However, studies supporting these interactions have since been withdrawn. Furthermore, recent crystallographic evidence does not support the view that ROR is a nuclear receptor of melatonin. Some other studies have proposed that melatonin indirectly regulates ROR activity rather than directly binding to ROR. This review aims to delve into the complex relationship of the ROR receptor with melatonin in terms of its structure, expression, function, and mechanism. Thus, we provide the latest evidence and views on direct binding as well as indirect regulation of ROR by melatonin, dissecting both viewpoints in-depth to provide a more comprehensive perspective on this issue.

Effects of melatonin supplementation on eating habits and appetite-regulating hormones: a systematic review of randomized controlled clinical and preclinical trials

Melatonin is a hormone involved in appetite regulation and food intake. Circadian chronorrupture caused by its absence has been associated with excessive food consumption, and there is evidence that exogenous melatonin supplementation can restore homeostasis. Therefore, the aim of this systematic review was to synthesize evidence from randomized controlled clinical and preclinical trials that evaluated the effects of exogenous melatonin supplementation on eating habits and appetite-regulating hormones. The protocol was registered in PROSPERO (number 42020175809). Medline, Scopus, Web of Science and Cochrane Library were systematically searched from January 2020 to February 2021. Of 3.695 articles identified, 2 clinical and 13 preclinical trials (n = 15) met the inclusion criteria. The outcomes were total food intake, calories, macronutrients, cholesterol intake, leptin and ghrelin levels. Interventions ranged from 28 to 336 days and dose of melatonin varied between 0.2 µg/mL of drinking water and 10 mg/day. Clinical trials were conducted with healthy adults, and preclinical trials with rodents and dogs. Of the 15 articles, five assessed food intake and leptin, four assessed food intake only, five assessed leptin only, and one assessed leptin and ghrelin serum levels. The majority of the articles were judged as having low risk of bias. Although findings are heterogeneous and do not allow a robust conclusion, this review adds to the growing body of evidence suggesting that exogenous melatonin may be a potential therapeutic agent against endocrine-metabolic disorders. This reversal is not necessarily associated with changes in food consumption, signaling that melatonin's metabolic effects may occur independently of energy intake. Further studies, especially with humans, are needed provide more evidences for melatonin supplementation in clinical practice, as well as to understand its role on eating habits and appetite-regulating hormones.

Single-cell RNA sequencing of preadipocytes reveals the cell fate heterogeneity induced by melatonin

Obesity is a global epidemic health disorder and associated with several diseases. Body weight-reducing effects of melatonin have been reported; however, no investigation toward examining whether the beneficial effects of melatonin are associated with preadipocyte heterogeneity has been reported. In this study, we profiled 25 071 transcriptomes of normal and melatonin-treated preadipocytes using scRNA-seq. By tSNE analysis, we present a cellular-state landscape for melatonin-treated preadipocytes that covers multiple-cell subpopulations, defined as cluster 0 to cluster 13. Cluster 0 and cluster 1 were the largest components of normal and melatonin-treated preadipocytes, respectively. G0S2, an inhibitor of adipose triglyceride lipase (ATGL), was significantly upregulated in cluster 0 and downregulated in cluster 1. We redefined cluster 0 as the G0S2-positive cluster (G0S2⁺ ) and cluster 1 as the G0S2-negative cluster (G0S2^- ). Through pseudotime analysis, the G0S2^- cluster cell differentiation trajectory was divided into three major structures, that is, the prebranch, the lipid catabolism branch, and the cell fate 2 branch. In vitro, G0S2 knockdown enhanced the expression levels of ATGL, BAT markers and fatty acid oxidation-related genes, but inhibited C/EBPα and PPARγ expression. In vivo, knockdown of G0S2 reduced the body weight gain in high-fat-fed mice. The beneficial effects of the G0S2^- cell cluster in promoting lipolysis and inhibiting adipogenesis are dependent on two major aspects: first, downregulation of the G0S2 gene in the G0S2^- cluster, resulting in activation of ATGL, which is responsible for the bulk of triacylglycerol hydrolase activity; and second, upregulation of FABP4 in the G0S2^- cluster, resulting in inhibition of PPARγ and further reducing adipogenesis.

Insight into the roles of melatonin in bone tissue and bone‑related diseases (Review)

Bone‑related diseases comprise a large group of common diseases, including fractures, osteoporosis and osteoarthritis (OA), which affect a large number of individuals, particularly the elderly. The progressive destruction and loss of alveolar bone caused by periodontitis is a specific type of bone loss, which has a high incidence and markedly reduces the quality of life of patients. With the existing methods of prevention and treatment, the incidence and mortality of bone‑related diseases are still gradually increasing, creating a significant financial burden to societies worldwide. To prevent the occurrence of bone‑related diseases, delay their progression or reverse the injuries they cause, new alternative or complementary treatments need to be developed. Melatonin exerts numerous physiological effects, including inducing anti‑inflammatory and antioxidative functions, resetting circadian rhythms and promoting wound healing and tissue regeneration. Melatonin also participates in the health management of bone and cartilage. In the present review, the potential roles of melatonin in the pathogenesis and progression of bone injury, osteoporosis, OA and periodontitis are summarized. Furthermore, the high efficiency and diversity of the physiological regulatory effects of melatonin are highlighted and the potential benefits of the use of melatonin for the clinical prevention and treatment of bone‑related diseases are discussed.

Pilot Clinical Trial of Time-Restricted Eating in Patients with Metabolic Syndrome

Metabolic syndrome (MetS) and erratic eating patterns are associated with circadian rhythm disruption which contributes to an increased cardiometabolic risks. Restricting eating period (time-restricted eating, TRE) can restore robust circadian rhythms and improve cardiometabolic health. We describe a protocol of the Time-Restricted Eating on Metabolic and Neuroendocrine homeostasis, Inflammation, and Oxidative Stress (TREMNIOS) pilot clinical trial in Polish adult patients with MetS and eating period of ≥14 h/day. The study aims to test the feasibility of TRE intervention and methodology for evaluating its efficacy for improving metabolic, neuroendocrine, inflammatory, oxidative stress and cardiac biomarkers, and daily rhythms of behavior for such population. Participants will apply 10-h TRE over a 12-week monitored intervention followed by a 12-week self-directed intervention. Changes in eating window, body weight and composition, biomarkers, and rhythms of behavior will be evaluated. Dietary intake, sleep, activity and wellbeing will be monitored with the myCircadianClock application and questionnaires. Adherence to TRE defined as the proportion of days recorded with app during the monitored intervention in which participants satisfied 10-h TRE is the primary outcome. TREMNIOS will also provide an exploratory framework to depict post-TRE changes in cardiometabolic outcomes and behavior rhythms. This protocol extends previous TRE-related protocols by targeting European population with diagnosed MetS and including long-term intervention, validated tools for monitoring dietary intake and adherence, and comprehensive range of biomarkers. TREMNIOS trial will lay the groundwork for a large-scale randomized controlled trial to determine TRE efficacy for improving cardiometabolic health in MetS population.

Time-Restricted Eating and Metabolic Syndrome: Current Status and Future Perspectives

Metabolic syndrome (MetS) occurs in ~30% of adults and is associated with increased risk of cardiovascular disease and diabetes mellitus. MetS reflects the clustering of individual cardiometabolic risk factors including central obesity, elevated fasting plasma glucose, dyslipidemia, and elevated blood pressure. Erratic eating patterns such as eating over a prolonged period per day and irregular meal timing are common in patients with MetS. Misalignment between daily rhythms of food intake and circadian timing system can contribute to circadian rhythm disruption which results in abnormal metabolic regulation and adversely impacts cardiometabolic health. Novel approaches which aim at restoring robust circadian rhythms through modification of timing and duration of daily eating represent a promising strategy for patients with MetS. Restricting eating period during a day (time-restricted eating, TRE) can aid in mitigating circadian disruption and improving cardiometabolic outcomes. Previous pilot TRE study of patients with MetS showed the feasibility of TRE and improvements in body weight and fat, abdominal obesity, atherogenic lipids, and blood pressure, which were observed despite no overt attempt to change diet quantity and quality or physical activity. The present article aims at giving an overview of TRE human studies of individuals with MetS or its components, summarizing current clinical evidence for improving cardiometabolic health through TRE intervention in these populations, and presenting future perspectives for an implementation of TRE to treat and prevent MetS. Previous TRE trials laid the groundwork and indicate a need for further clinical research including large-scale controlled trials to determine TRE efficacy for reducing long-term cardiometabolic risk, providing tools for sustained lifestyle changes and, ultimately, improving overall health in individuals with MetS.

Sleeve gastrectomy in patients with severe obesity restores circadian rhythms and their relationship with sleep pattern

Advances in research have linked alterations of circadian rhythms with obesity. However, few studies have focused on the recovery of the circadian expression after a weight loss treatment. Our aim was to study the alterations of the circadian rhythmicity due to morbid obesity and the recovery of the circadian pattern after weight loss in a cohort of patients who underwent sleeve gastrectomy. For this purpose, 41 patients with severe obesity (75% women; age [mean (SD)] 49.7 ± 10 years; BMI 44.3 ± 6.2 kg/m2) were monitored before bariatric surgery and 9 months afterward. On both occasions, activity and wrist temperature were determined by actigraphy and were related with weight loss. Anthropometric, biochemical, and sleep-related variables, along with dietary intake and physical activity, were analyzed in relation with circadian rhythmicity. Results show significant differences in the circadian expression before and after 9 months of bariatric surgery, with more stable and less fragmented rhythms after weight loss. Moreover, only after surgery were the circadian variables associated to sleep timing and chronotype. The findings of this study indicate that weight loss treatment in patients with morbid obesity improves the circadian rhythm expression, and in such a way that it could be associated with better sleep quality. Moreover, it allows the recovery of the relationship between sleep patterns and circadian rhythm that was lost due to the obesity.

Removal of melatonin receptor type 1 signalling induces dyslipidaemia and hormonal changes in mice subjected to environmental circadian disruption

Background

Melatonin is a hormone secreted by the pineal gland in a circadian rhythmic manner with peak synthesis at night. Melatonin signalling was suggested to play a critical role in metabolism during the circadian disruption.

Methods

Melatonin-proficient (C3H-f+/+ or WT) and melatonin receptor type 1 knockout (MT1 KO) male and female mice were phase-advanced (6 hours) once a week for 6 weeks. Every week, we measured weight, food intake and basal glucose levels. At the end of the experiment, we sacrificed the animals and measured the blood's plasma for lipids profile (total lipids, phospholipids, triglycerides and total cholesterol), metabolic hormones profiles (ghrelin, leptin, insulin, glucagon, glucagon-like-peptide and resistin) and the body composition.

Results

Environmental circadian disruption (ECD) did not produce any significant effects in C3H-f+/+, while it increased lipids profile in MT1 KO with the significant increase observed in total lipids and triglycerides. For metabolic hormones profile, ECD decreased plasma ghrelin and increased plasma insulin in MT1 KO females. Under control condition, MT1 KO females have significantly different body weight, fat mass, total lipids and total cholesterol than the control C3H-f+/+ females.

Conclusion

Our data show that melatonin-proficient mice are not affected by ECD. When the MT1 receptors are removed, ECD induced dyslipidaemia in males and females with females experiencing the most adverse effect. Overall, our data demonstrate that MT1 signalling is an essential modulator of lipid and metabolic homeostasis during ECD.

Is Melatonin the Cornucopia of the 21st Century?

Melatonin, an indoleamine hormone produced and secreted at night by pinealocytes and extra-pineal cells, plays an important role in timing circadian rhythms (24-h internal clock) and regulating the sleep/wake cycle in humans. However, in recent years melatonin has gained much attention mainly because of its demonstrated powerful lipophilic antioxidant and free radical scavenging action. Melatonin has been proven to be twice as active as vitamin E, believed to be the most effective lipophilic antioxidant. Melatonin-induced signal transduction through melatonin receptors promotes the expression of antioxidant enzymes as well as inflammation-related genes. Melatonin also exerts an immunomodulatory action through the stimulation of high-affinity receptors expressed in immunocompetent cells. Here, we reviewed the efficacy, safety and side effects of melatonin supplementation in treating oxidative stress- and/or inflammation-related disorders, such as obesity, cardiovascular diseases, immune disorders, infectious diseases, cancer, neurodegenerative diseases, as well as osteoporosis and infertility.

Melatonin supplementation in the management of obesity and obesity-associated disorders: A review of physiological mechanisms and clinical applications

Despite the evolving advances in clinical approaches to obesity and its inherent comorbidities, the therapeutic challenge persists. Among several pharmacological tools already investigated, recent studies suggest that melatonin supplementation could be an efficient therapeutic approach in the context of obesity. In the present review, we have amalgamated the evidence so far available on physiological effects of melatonin supplementation in obesity therapies, addressing its effects upon neuroendocrine systems, cardiometabolic biomarkers and body composition. Most studies herein appraised employed melatonin supplementation at dosages ranging from 1 to 20 mg/day, and most studies followed up participants for periods from 3 weeks to 12 months. Overall, it was observed that melatonin plays an important role in glycaemic homeostasis, in addition to modulation of white adipose tissue activity and lipid metabolism, and mitochondrial activity. Additionally, melatonin increases brown adipose tissue volume and activity, and its antioxidant and anti-inflammatory properties have also been demonstrated. There appears to be a role for melatonin in adiposity reduction; however, several questions remain unanswered, for example melatonin baseline levels in obesity, and whether any seeming hypomelatonaemia or melatonin irresponsiveness could be clarifying factors. Supplementation dosage studies and more thorough clinical trials are needed to ascertain not only the relevance of such findings but also the efficacy of melatonin supplementation.

Sweet dreams: therapeutic insights, targeting imaging and physiologic evidence linking sleep, melatonin and diabetic nephropathy

Melatonin is the main biochronologic molecular mediator of circadian rhythm and sleep. It is also a powerful antioxidant and has roles in other physiologic pathways. Melatonin deficiency is associated with metabolic derangements including glucose and cholesterol dysregulation, hypertension, disordered sleep and even cancer, likely due to altered immunity. Diabetic nephropathy (DN) is a key microvascular complication of both type 1 and 2 diabetes. DN is the end result of a complex combination of metabolic, haemodynamic, oxidative and inflammatory factors. Interestingly, these same factors have been linked to melatonin deficiency. This report will collate in a clinician-oriented fashion the mechanistic link between melatonin deficiency and factors contributing to DN.

The roles of melatonin on kidney injury in obese and diabetic conditions

Obesity is a common and complex health problem worldwide and can induce the development of Type 2 diabetes. Chronic kidney disease (CKD) is a complication occurring as a result of obesity and diabetic conditions that lead to an increased mortality rate. There are several mechanisms and pathways contributing to kidney injury in obese and diabetic conditions. The expansion of adipocytes triggers proinflammatory cytokines release into blood circulation and bind with the receptors at the cell membranes of renal tissues leading to kidney injury. Obesity-mediated inflammation, oxidative stress, apoptosis, and mitochondrial dysfunction are the important causes and progression of CKD. Melatonin (N-acetyl-5-methoxytryptamine) is a neuronal hormone that is synthesized by the pineal gland and plays an essential role in regulating several physiological functions in the human body. Moreover, melatonin has pleiotropic effects such as antioxidant, anti-inflammation, antiapoptosis. In this review, the relationship between obesity, diabetic condition, and kidney injury and the renoprotective effect of melatonin in obese and diabetic conditions from in vitro and in vivo studies have been summarized and discussed.

The Role of Prenatal Melatonin in the Regulation of Childhood Obesity

There is a growing awareness that pregnancy can set the foundations for an array of diverse medical conditions in the offspring, including obesity. A wide assortment of factors, including genetic, epigenetic, lifestyle, and diet can influence foetal outcomes. This article reviews the role of melatonin in the prenatal modulation of offspring obesity. A growing number of studies show that many prenatal risk factors for poor foetal metabolic outcomes, including gestational diabetes and night-shift work, are associated with a decrease in pineal gland-derived melatonin and associated alterations in the circadian rhythm. An important aspect of circadian melatonin’s effects is mediated via the circadian gene, BMAL1, including in the regulation of mitochondrial metabolism and the mitochondrial melatoninergic pathway. Alterations in the regulation of mitochondrial metabolic shifts between glycolysis and oxidative phosphorylation in immune and glia cells seem crucial to a host of human medical conditions, including in the development of obesity and the association of obesity with the risk of other medical conditions. The gut microbiome is another important hub in the pathoetiology and pathophysiology of many medical conditions, with negative consequences mediated by a decrease in the short-chain fatty acid, butyrate. The effects of butyrate are partly mediated via an increase in the melatoninergic pathway, indicating interactions of the gut microbiome with melatonin. Some of the effects of melatonin seem mediated via the alpha 7 nicotinic receptor, whilst both melatonin and butyrate may regulate obesity through the opioidergic system. Oxytocin, a recently recognized inhibitor of obesity, may also be acting via the opioidergic system. The early developmental regulation of these processes and factors by melatonin are crucial to the development of obesity and many diverse comorbidities.

A circadian rhythm-related MTNR1B genetic variant (rs10830963) modulate body weight change and insulin resistance after 9 months of a high protein/low carbohydrate vs a standard hypocaloric diet

BACKGROUND & AIMS

The risk allele (G) of rs10830963 in the melatonin receptor 1 B (MTNR1B) gene presents an association with biochemical parameters and obesity. We study the effect of this SNP on insulin resistance and weight loss secondary to two hypocaloric diets.

METHODS

270 obese subjects were randomly allocated during 9 months (Diet HP: a high protein/low carbohydrate vs. Diet S: a standard severe hypocaloric diets). Anthropometric parameters, fasting blood glucose, C-reactive protein (CRP), insulin concentration, insulin resistance (HOMA-IR), lipid profile and adipocytokines levels were measured. Genotype of MTNR1B gene polymorphism (rs10830963) was evaluated.

RESULTS

All adiposity parameters, systolic blood pressure and leptin levels decreased in all subjects after both diets. This improvement of adiposity parameters was higher in non-G allele carriers than G allele carriers. After weight loss with Diet HP, (CC vs. CG + GG at 9 months); total cholesterol (delta: -9.9 ± 2.4 mg/dl vs. -4.8 ± 2.2 mg/dl:p < 0.05), LDL-cholesterol (delta: -8.3 ± 1.9 mg/dl vs. -5.1 ± 2.2 mg/dl: p < 0.05), insulin (delta: -4.7 ± 0.8 UI/L vs. -0.9 ± 1.0 UI/L: p < 0.05), triglycerides (delta: -17.7 ± 3.9 mg/dl vs. -6.1 ± 2.8 mg/dl: p < 0.05) and HOMA IR (delta: -0.8 ± 0.2 units vs. -0.2 ± 0.1 units: p < 0.05) improved only in no G allele carriers. After weight loss with Diet S in non G allele carriers, insulin levels (delta (CC vs. CG + GG): -3.4 ± 0.6 UI/L vs. -1.2 ± 0.4 UI/L: p < 0.05), triglycerides (delta: -29.2 ± 3.4 mg/dl vs. -8.2 ± 3.8 mg/dl: p < 0.05), HOMA-IR (delta (CC vs. CG + GG): -1.1 ± 0.2 units vs. -0.1 ± 0.1 units: p < 0.05), total cholesterol (delta: -15.9 ± 7.4 mg/dl vs. -5.8 ± 2.9 mg/dl:ns) and LDL-cholesterol (delta: -13.7 ± 5.9 mg/dl vs. -6.0 ± 2.9 mg/dl: ns) decreased, too.

CONCLUSIONS

our study detected a relationship of rs10830963 variant of MTNR1B gene with adiposity changes, cholesterol changes and insulin resistance modification induced by two different hypocaloric during 9 months.

Sirtuin1 Role in the Melatonin Protective Effects Against Obesity-Related Heart Injury

Obesity is a worldwide epidemic disease that induces important structural and functional changes to the heart and predisposes a patient to devastating cardiac complications. Sirtuin1 (SIRT1) has been found to have roles in regulating cardiac function, but whether it can help in cardioprotection is not clear. The aim of the present study was to determine whether melatonin, by modulating SIRT1 and in turn mitochondria signaling, may alleviate obesity-induced cardiac injuries. We investigated 10 lean control mice and 10 leptin-deficient obese mice (ob/ob) orally supplemented with melatonin for 8 weeks, as well as equal numbers of age-matched lean and ob/ob mice that did not receive melatonin. Hearts were evaluated using multiple parameters, including biometric values, morphology, SIRT1 activity and expression of markers of mitochondria biogenesis, oxidative stress, and inflammation. We observed that ob/ob mice experienced significant heart hypertrophy, infiltration by inflammatory cells, reduced SIRT1 activity, altered mitochondrial signaling and oxidative balance, and overexpression of inflammatory markers. Notably, melatonin supplementation in ob/ob mice reverted these obesogenic heart alterations. Melatonin prevented heart remodeling caused by obesity through SIRT1 activation, which, together with mitochondrial pathways, reduced oxidative stress and inflammation.

Physiological mechanisms underlying children's circannual growth patterns and their contributions to the obesity epidemic in elementary school age children

Several studies since the 1990s have demonstrated that children increase their body mass index at a faster rate during summer months compared with the school year, leading some to conclude that the out-of-school summer environment is responsible. Other studies, however, have suggested that seasonality may play a role in children's height and weight changes across the year. This article reviews evidence for seasonal differences in the rate of children's height and weight gain and proposes potential physiological mechanisms that may explain these seasonal variations.