Melatonin administration lowers biomarkers of oxidative stress and cardio-metabolic risk in type 2 diabetic patients with coronary heart disease: A randomized, double-blind, placebo-controlled trial. Clin Nutr. 2017;. [PMID: 29275919 DOI: 10.1016/j.clnu.2017.12.004]

Protective effects of ghrelin on pancreas in fructose diet and streptozotocin-induced diabetic rats

Ghrelin, which is widely expressed in central and peripheral tissues, has several metabolic effects. It has been suggested that these effects may include anti-inflammatory, anti-oxidant, and anti-apoptotic effects. Therefore, we aimed to investigate the effects of ghrelin administered to diabetic rats on DNA repair and apoptosis mechanisms, and differences in oxidative stress (OS) and pancreatic hormone levels in the pancreas. Twenty-one rats were randomly divided into three groups: control, type 2 diabetes mellitus (T2DM), and T2DM treated with ghrelin (T2DM + ghrelin). We examined PCNA and PARP-1 to evaluate the effect of ghrelin on DNA repair, caspase-3 and caspase-9 to evaluate its effect on apoptosis, and insulin and glucagon to evaluate its role in regulating glucose homeostasis by immunohistochemistry in diabetic rats. Malondialdehyde, glutathione, and protein carbonyl levels, as well as catalase, glutathione-S-transferase, and superoxide dismutase (SOD) activities, were measured spectrophotometrically to detect the ghrelin effect on OS. Homeostasis model assessment for insulin resistance (HOMA-IR) and pancreatic insulin levels were assessed by ELISA method. Ghrelin may be a potential regulator of apoptosis as it significantly reduced the number of caspase-3 and caspase-9 immunopositive cells (p < 0.0001). In addition, ghrelin treatment reduced OS by decreasing glutathione (p < 0.001), malondialdehyde, and protein carbonyl, as well as the activity of SOD (p < 0.05) in diabetic rats. The results suggest that ghrelin is a potential apoptotic regulator and may be considered as a therapeutic agent due to its significant ability to suppress OS in T2DM.

Melatonin ameliorates inflammation and improves outcomes of ischemia/reperfusion injury in patients undergoing coronary artery bypass grafting surgery: a randomized placebo-controlled study

To investigate the protective role of high dose melatonin concerning myocardial I/R injury and inflammation in patients undergoing on-pump coronary artery bypass grafting (CABG) surgery by evaluating IR/inflammatory biomarkers and clinical outcomes. This was a prospective; randomized; single-blinded placebo-controlled study conducted at cardio-thoracic surgery department of the Academy of the Cardiovascular and Thoracic Surgery, Ain Shams University. Eligible patients were randomly allocated to; melatonin-treated group (MTG) or placebo-treated group (PTG). The MTG (n = 17) received 60 mg/day melatonin capsules daily starting 5 days before surgery in addition to the standard of care. PTG (n = 17) received placebo also 5 days before surgery plus standard of care. The levels of nuclear factor kappa beta (NF-κb) (primary outcome), tumor necrosis factor (TNF-α), cardiac troponins I, and IL-6 levels were all assessed for both groups at five time points: baseline before melatonin or placebo administration (T0), before cross-clamp application(T1), 5 min after cross-clamp removal(T2), 6 h after cross-clamp removal(T3) and 24 h after cross-clamp removal(T4). Blood pressure was assessed at baseline, pre-operative and 24-hours post-operative. The Quality of recovery-40 score (QOR-40) was assessed for both groups on day 4 after surgery. TNF-α levels decreased in the MTG at T1(p = 0.034) versus PTG. At T2(p = 0.005), and T3(p = 0.04), TNF-α significantly increased in PTG versus MTG. Troponins significantly increased in PTG at T3 (p = 0.04) versus MTG. NF-κB levels declined at T1 (p = 0.013) and T2 (p = 0.0001) in MTG compared to PTG. IL-6 significantly increased in PTG versus MTG at T3 (p = 0.04). The QOR-40 score significantly decreased in MTG versus PTG. MTG had statistically significant decrease in DBP compared to the placebo group (p = 0.024). MTG had a statistically significant shorter intubation time than did the placebo group (p = 0.03). Melatonin 60 mg was well-tolerated without any reported side effects. Our findings suggested that melatonin could ameliorate myocardial I/R injury after on-pump CABG and that this outcome was essentially correlated to its antiapoptotic and anti-inflammatory effects. Trial registration: ClinicalTrials.gov registration number NCT05552586, 9/2022.

Effects of melatonin supplementation on metabolic parameters, oxidative stress, and inflammatory biomarkers in diabetic patients with chronic kidney disease: study protocol for a double-blind, randomized controlled trial

INTRODUCTION

Chronic kidney disease (CKD) is a pervasive disease of the current century that usually affects the adult population, especially people with diabetes and hypertension. According to the recent studies, inflammation, oxidative stress, apoptosis, and mitochondrial dysfunction are determining risk factors in the pathogenesis of CKD. Melatonin as a strong antioxidant is produced in various tissues including the kidneys. The present clinical trial aims to examine the efficacy of melatonin supplementation on metabolic parameters, oxidative stress, and inflammatory biomarkers in diabetic patients with CKD.

METHODS

This is a double-blind, randomized, placebo-controlled clinical study that will be investigated the impacts of melatonin supplementation in diabetic patients with CKD. Laboratory findings will be applied to diagnose diabetic CKD. Forty-eight eligible diabetic subjects with CKD will be selected and randomly assigned to receive 5 mg melatonin tablets or identical placebo twice daily for 10 weeks. Participants will be asked to remain on their usual diet and physical activity. The primary outcome of this study is changes in oxidative stress and inflammatory biomarkers. The secondary outcomes include changes in lipid profile, renal function indicators, fasting blood sugar and serum insulin, systolic and diastolic blood pressure (SBP and DBP), serum phosphorous concentration, sleep quality, body weight, body mass index (BMI), and waist circumference (WC). Statistical analysis will be conducted using the SPSS software (version 25).

DISCUSSION

We hypothesize that melatonin administration may be useful for treating diabetic CKD by modulating oxidative stress, inflammation, regulating lipid metabolism, and increasing insulin sensitivity through different mechanisms. The current trial will exhibit the effects of melatonin, whether negative or positive, on diabetic CKD status.

ETHICAL ASPECTS

The current trial received approval from Medical Ethics Committee of Tehran University of Medical Sciences, Tehran, Iran (IR.TUMS.SHARIATI.REC.1402.072).

TRIAL REGISTRATION

This study had been registered in Iranian Registry of Clinical Trials.

REGISTRATION NUMBER

IRCT20170202032367N9 on 11 August 2023. https://www.irct.ir/trial/70709 .

Dietary Antioxidants and Natural Compounds in Preventing Thrombosis and Cardiovascular Disease

Reactive oxygen species (ROS) contribute to endothelial dysfunction, platelet activation, and coagulation abnormalities, promoting thrombus formation. Given the growing interest in non-pharmacological approaches to modulate oxidative stress, we examine the potential of various dietary interventions and antioxidant supplementation in reducing oxidative damage and preventing thrombotic events. Key dietary patterns, such as the Mediterranean, Dietary Approaches to Stop Hypertension (DASH), and ketogenic diets, as well as antioxidant-rich supplements like curcumin, selenium, and polyphenols, demonstrate promising effects in improving oxidative stress markers, lipid profiles, and inflammatory responses. This review highlights recent advances in the field, drawing from in vitro, ex vivo, and clinical studies, and underscores the importance of integrating dietary strategies into preventive and therapeutic approaches for managing thrombosis and cardiovascular health. Further research is needed to better understand long-term effects and personalize these interventions for optimizing patient outcomes.

Effects of melatonin supplementation on markers of inflammation and oxidative stress in patients with diabetes: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND & AIMS

Diabetes mellitus is a metabolic disorder, in which chronic systemic inflammation and oxidative stress contribute to the progression of this condition and its complications. Melatonin, a hormone known for its potent antioxidant and anti-inflammatory properties, has emerged as a potential therapeutic intervention in diabetes. This review aims to evaluate the effects of melatonin supplementation on markers of oxidative stress and inflammation in diabetic patients.

METHODS

A thorough literature search of databases, including PubMed, Embase, Web of Science, Cochrane Central, CNKI, and Scopus, was conducted through October 2023. We included randomized controlled trials investigating the effects of melatonin on markers of inflammation and oxidative stress, compared to placebo in patients with diabetes. The data was analyzed using the random-effects model and the summary effect size was determined using the standardized mean difference (SMD) with 95% confidence interval (CI).

RESULTS

Fourteen studies with 823 participants were included. Our analysis indicates that melatonin can lead to significant reductions in levels of C-reactive protein (CRP) [SMD = -0.75; 95% CI: -1.37, -0.12; P = 0.018], tumor necrosis factor-alpha (TNF-α) [SMD = -0.40; 95% CI: -0.64, -0.15; P = 0.001], interleukin (IL)-1 [SMD = -0.75; 95% CI: -1.03, -0.47; P < 0.0001], IL-6 [SMD = -0.79; 95% CI: -1.07, -0.51; P < 0.0001], and malondialdehyde (MDA) [SMD = -0.61; 95% CI: -0.80, -0.43; P < 0.0001]. Furthermore, we found a significant increase in levels of total antioxidant capacity (TAC) [SMD = 0.81; 95% CI: 0.12, 1.51; P = 0.021], glutathione (GSH) [SMD = 0.66; 95% CI: 0.28, 1.03; P = 0.001], and superoxide dismutase (SOD) [SMD = 1.69; 95% CI: 0.80, 2.58; P < 0.0001] following melatonin consumption in patients with diabetes.

CONCLUSION

Melatonin supplementation is a promising complementary strategy to attenuate oxidative stress and inflammation in diabetic patients.

Melatonin rescues pregnant female mice and their juvenile offspring from high fat diet-induced alzheimer disease neuropathy

High fat diet (HFD) is a prime factor, which contributes to the present epidemic of metabolic syndrome. Prolonged intake of HFD induces oxidative stress (OS) that in turn causes neuroinflammation, neurodegeneration, insulin resistance, amyloid burden, synaptic dysfunction and cognitive impairment hence leading to Alzheimer's disease neuropathy. Melatonin (secreted by the Pineal gland) has the potential to nullify the toxic effects of reactive oxygen species (ROS) and have been shown to ameliorate various complications induced by HFD in rodent models. This study aimed to assess the neurotherapeutic effects of melatonin on HFD-induced neuroinflammation and neurodegeneration mediated by OS in pregnant female mice and their offspring. Western blotting, immunohistochemistry and antioxidant enzyme assays were used for quantification of samples from the hippocampal region of the brain of pregnant albino mice and their offspring. Short- and long-term memory was assessed by Y-maze and Morris Water Maze tests. HFD significantly induced OS leading to AD like neuropathology in the pregnant mice and their offspring while melatonin administration simultaneously with the HFD significantly prevented this neuropathy. This study reports that melatonin exerts these effects through the stimulation of SIRT1/Nrf2/HO-1 pathway that in turn reduces the HFD-induced OS and its downstream signaling. In conclusion melatonin prevents HFD-induced multiple complications that ultimately leads to the memory dysfunction in pregnant female mice and their successive generation via activation of SIRT1/Nrf2 signaling pathway.

Effect of melatonin supplementation on body composition and blood pressure in adults: A systematic review and Dose-Response meta-analysis of randomized controlled trial

Background

Several randomized controlled trials (RCTs) have explored the impact of melatonin on body composition and blood pressure (BP). However, the findings from these studies remain a topic of debate. This systematic review and meta-analysis of RCTs sought to evaluate the effects of melatonin consumption on body composition (body weight (BW), body mass index (BMI), waist circumference (WC), hip circumference (HC)) and asleep/daytime BP (systolic blood pressure (SBP) and diastolic blood pressure (DBP)) in adults.

Methods

In order to identify eligible RCTs, a systematic literature search was carried out up to June 2024 in PubMed, Embase, Scopus, and Web of Science without any language restrictions. The I2 statistic was used to perform heterogeneity tests on the selected studies. After evaluating random effects models based on heterogeneity tests, the weighted mean differences (WMD) with a 95 % confidence interval (CI) were calculated using pooled data.

Results

Overall, 28 studies (n = 1,543 participants) met our inclusion criteria. A pooled analysis of studies demonstrated that melatonin consumption led to a significant reduction in HC (WMD: 1.21 cm; 95 % CI: 1.94 to -0.49; P = 0.001), and daytime DBP (WMD: 1.40 mmHg; 95 % CI: 2.46 to -0.34; P = 0.009) in comparison with the control group. However, no substantial effects were observed on BW, BMI, WC, and SBP compared to the control group. Conclusion: The current meta-analysis of RCTs shows that treatment with melatonin reduces HC and daytime DBP levels in adults. However, further well-designed RCTs with large sample sizes and long durations are necessary to determine the effect of this supplement on body composition and BP.

Melatonin supplementation counteracts fiber loss in knee ligaments of diabetes-induced rats

Diabetes mellitus (DM) is a prevalent metabolic disease. The clinical impact of sustained hyperglycemia on ligament healing has not been well characterized. Diabetes is a known cause of macro-, microvascular, and diabetic ulcer healing difficulties among tissues. Therefore, we aimed to investigate the healing potential occurring in injured and healthy ligaments among diabetic and healthy individuals using a rat model. We hypothesize that DM may contribute to altering the knee medial collateral ligament (MCL), thus its morphology, biochemical fitness, and functionality. The study cohort consisted of 40 rats. The animals were randomized into four equal groups. Groups I and II (20 rats) received saline subcutaneously and served as controls. Groups III and IV (20 rats) were injected with a single dose of streptozotocin (STZ). All animals underwent surgery to cut the left tibial collateral ligament in the hind limb and suture it. The access site was sutured to create inflammation and study the regenerative capacities of animals with normal carbohydrate metabolism and pharmacologically induced diabetes. Each animal then underwent sham surgery to access and suture the right tibial collateral ligament in the hind limb without ligament intervention. After the animals had undergone surgeries, groups II and IV were given melatonin supplementation for 4 weeks. Rats with DM presented with more fibrosis and calcification of the MCL and decreased healing potential. Treatment with melatonin in diabetic rats mitigated alterations and improved the antioxidant status of ligaments from the diabetic group.

Exploring effects of melatonin supplementation on insulin resistance: An updated systematic review of animal and human studies

BACKGROUND

Insulin resistance (IR), defined as an impaired response to insulin stimulation of target tissues, is a substantial determinant of many metabolic disorders. This study aimed to update the findings of the previous systematic review evidence regarding the effect of melatonin on factors related to IR, including hyperinsulinemia, hyperglycemia, homeostasis model assessment of insulin resistance (HOMA-IR), and quantitative insulin sensitivity check index (QUICKI).

METHODS

We systematically reviewed the evidence on the impact of melatonin supplementation on IR indices, fasting insulin, and fasting plasma glucose. PubMed, ScienceDirect, SCOPUS, and Google Scholar databases were searched until March 2024.

RESULTS

We identified 6114 potentially relevant articles during the search. Eighteen animal studies and 15 randomized clinical trials met the inclusion criteria. The results indicated that melatonin supplementation reduced fasting plasma glucose (FPG, 14 out of 29 studies), fasting insulin (22 out of 28 studies), HOMA-IR (28 out of 33 studies), and increased QUICKI (7 out of 7 studies). According to RCT studies, melatonin treatment at a dosage of 10 mg reduced HOMA-IR levels in individuals with various health conditions.

CONCLUSION

According to most evidence, melatonin supplementation may decrease fasting insulin and HOMA-IR and increase QUICKI but may not affect FPG.

Dysregulated 24 h melatonin secretion associated with intrinsically photosensitive retinal ganglion cell function in diabetic retinopathy: a cross-sectional study

AIMS/HYPOTHESIS

The aim of this study was to explore whether diabetic retinopathy is associated with alterations of the circadian system, and to examine the role of reduced intrinsically photosensitive retinal ganglion cell (ipRGC) function.

METHODS

Participants with type 2 diabetes, with diabetic retinopathy (n=14) and without diabetic retinopathy (n=9) underwent 24 h blood sampling for melatonin and cortisol under controlled laboratory conditions. ipRGC function was inferred from the post-illumination pupil response (PIPR). Habitual sleep duration, efficiency and variability were assessed by actigraphy.

RESULTS

Participants with diabetic retinopathy compared to participants without diabetic retinopathy had smaller PIPR (p=0.007), lower 24 h serum melatonin output (p=0.042) and greater day-to-day sleep variability (p=0.012). By contrast, 24 h cortisol profiles, sleep duration and efficiency were similar in both groups. Six individuals with diabetic retinopathy had no detectable dim-light melatonin onset. PIPR correlated with 24 h mean melatonin levels (r=0.555, p=0.007).

CONCLUSIONS/INTERPRETATION

ipRCG dysfunction in diabetic retinopathy is associated with disruptions of the 24 h melatonin rhythm, suggesting circadian dysregulation in diabetic retinopathy.

Effects of melatonin on blood pressure, arterial stiffness and quality of life in postmenopausal women: A randomized controlled trial

OBJECTIVES

Studies suggest that melatonin may promote cardiovascular protection. Previous trials have primarily been performed on co-morbid patients. Little information exist on the effect in postmenopausal women with general good health.

DESIGN, PARTICIPANTS AND INTERVENTION

In a double-blinded placebo-controlled study, we randomized 41 postmenopausal women to either 10 mg melatonin per day or placebo for 3 months.

OUTCOME MEASURES

Outcomes of the trial was changes in blood pressure, pulse wave velocity (PWV), and quality of sleep evaluated by Pittsburgh Sleep Quality Index (PSQI).

RESULTS

Thirty-nine women completed the study. Mean age was 63 years (range 55-75 years). Over the 3 months of the trial, PWV did not differ between groups: Placebo 1.1% (IQR -2.1;9.9) vs. melatonin 0.0% (IQR-9.8;4.1), p = 0.43). The were no significant differences in blood pressure bewteen melatonin and placebo group. Both groups had a pour quality of sleep at baseline (placebo: PSQI 6.0 (IQR 3.3; 8.8) vs. melatonin PSQI 6.0 (IQR 3.0; 10.0), p = 0.94), which did not change in response to treatment.

CONCLUSION

In healthy postmenopausal women, supplementation with 10 mg melatonin was well-tolerated, but we did not observe any significant improvements in pulse wave velocity, blood pressure or quality of sleep compared with placebo.

Exploring melatonin's multifaceted role in female reproductive health: From follicular development to lactation and its therapeutic potential in obstetric syndromes

BACKGROUND

Melatonin is mainly secreted by the pineal gland during darkness and regulates biological rhythms through its receptors in the suprachiasmatic nucleus of the hypothalamus. In addition, it also plays a role in the reproductive system by affecting the function of the hypothalamic-pituitary-gonadal axis, and by acting as a free radical scavenger thus contributing to the maintenance of the optimal physiological state of the gonads. Besides, melatonin can freely cross the placenta to influence fetal development. However, there is still a lack of overall understanding of the role of melatonin in the reproductive cycle of female mammals.

AIM OF REVIEW

Here we focus the role of melatonin in female reproduction from follicular development to delivery as well as the relationship between melatonin and lactation. We further summarize the potential role of melatonin in the treatment of preeclampsia, polycystic ovary syndrome, endometriosis, and ovarian aging.

KEY SCIENTIFIC CONCEPTS OF REVIEW

Understanding the physiological role of melatonin in female reproductive processes will contribute to the advancement of human fertility and reproductive medicine research.

The latest emerging drugs for the treatment of diabetic cardiomyopathy

INTRODUCTION

Diabetic cardiomyopathy (DCM) is a serious complication of diabetes mellitus involving multiple pathophysiologic mechanisms. In addition to hypoglycemic agents commonly used in diabetes, metabolism-related drugs, natural plant extracts, melatonin, exosomes, and rennin-angiotensin-aldosterone system are cardioprotective in DCM. However, there is a lack of systematic summarization of drugs for DCM.

AREAS COVERED

In this review, the authors systematically summarize the most recent drugs used for the treatment of DCM and discusses them from the perspective of DCM pathophysiological mechanisms.

EXPERT OPINION

We discuss DCM drugs from the perspective of the pathophysiological mechanisms of DCM, mainly including inflammation and metabolism. As a disease with multiple pathophysiological mechanisms, the combination of drugs may be more advantageous, and we have discussed some of the current studies on the combination of drugs.

The potential of therapeutic strategies targeting mitochondrial biogenesis for the treatment of insulin resistance and type 2 diabetes mellitus

Type 2 diabetes mellitus (T2DM) is a persistent metabolic disorder marked by deficiencies in insulin secretion and/or function, affecting various tissues and organs and leading to numerous complications. Mitochondrial biogenesis, the process by which cells generate new mitochondria utilizing existing ones plays a crucial role in energy homeostasis, glucose metabolism, and lipid handling. Recent evidence suggests that promoting mitochondrial biogenesis can alleviate insulin resistance in the liver, adipose tissue, and skeletal muscle while improving pancreatic β-cell function. Moreover, enhanced mitochondrial biogenesis has been shown to ameliorate T2DM symptoms and may contribute to therapeutic effects for the treatment of diabetic nephropathy, cardiomyopathy, retinopathy, and neuropathy. This review summarizes the intricate connection between mitochondrial biogenesis and T2DM, highlighting the potential of novel therapeutic strategies targeting mitochondrial biogenesis for T2DM treatment and its associated complications. It also discusses several natural products that exhibit beneficial effects on T2DM by promoting mitochondrial biogenesis.

Melatonin as a Chronobiotic and Cytoprotector in Non-communicable Diseases: More than an Antioxidant

A circadian disruption, manifested by disturbed sleep and low-grade inflammation, is commonly seen in noncommunicable diseases (NCDs). Cardiovascular, respiratory and renal disorders, diabetes and the metabolic syndrome, cancer, and neurodegenerative diseases are among the most common NCDs prevalent in today's 24-h/7 days Society. The decline in plasma melatonin, which is a conserved phylogenetic molecule across all known aerobic creatures, is a constant feature in NCDs. The daily evening melatonin surge synchronizes both the central pacemaker located in the hypothalamic suprachiasmatic nuclei (SCN) and myriads of cellular clocks in the periphery ("chronobiotic effect"). Melatonin is the prototypical endogenous chronobiotic agent. Several meta-analyses and consensus studies support the use of melatonin to treat sleep/wake cycle disturbances associated with NCDs. Melatonin also has cytoprotective properties, acting primarily not only as an antioxidant by buffering free radicals, but also by regulating inflammation, down-regulating pro-inflammatory cytokines, suppressing low-grade inflammation, and preventing insulin resistance, among other effects. Melatonin's phylogenetic conservation is explained by its versatility of effects. In animal models of NCDs, melatonin treatment prevents a wide range of low-inflammation-linked alterations. As a result, the therapeutic efficacy of melatonin as a chronobiotic/cytoprotective drug has been proposed. Sirtuins 1 and 3 are at the heart of melatonin's chronobiotic and cytoprotective function, acting as accessory components or downstream elements of circadian oscillators and exhibiting properties such as mitochondrial protection. Allometric calculations based on animal research show that melatonin's cytoprotective benefits may require high doses in humans (in the 100 mg/day range). If melatonin is expected to improve health in NCDs, the low doses currently used in clinical trials (i.e., 2-10 mg) are unlikely to be beneficial. Multicentre double-blind studies are required to determine the potential utility of melatonin in health promotion. Moreover, melatonin dosage and levels used should be re-evaluated based on preclinical research information.

Melatonin supplementation does not alter vascular function or oxidative stress in healthy normotensive adults on a high sodium diet

High sodium diets (HSD) can cause vascular dysfunction, in part due to increases in reactive oxygen species (ROS). Melatonin reduces ROS in healthy and clinical populations and may improve vascular function. The purpose was to determine the effect of melatonin supplementation on vascular function and ROS during 10 days of a HSD. We hypothesized that melatonin supplementation during a HSD would improve vascular function and decrease ROS levels compared to HSD alone. Twenty-seven participants (13 M/14 W, 26.7 ± 2.9 years, BMI: 23.6 ± 2.0 kg/m2 , BP: 110 ± 9/67 ± 7 mmHg) were randomized to a 10-day HSD (6900 mg sodium/d) supplemented with either 10 mg of melatonin (HSD + MEL) or a placebo (HSD + PL) daily. Brachial artery flow-mediated dilation, a measure of macrovascular function, (HSD + PL: 7.1 ± 3.8%; HSD + MEL: 6.7 ± 3.4%; p = 0.59) and tissue oxygenation index (TSI) reperfusion rate, a measure of microvascular reactivity, (HSD + PL: 0.21 ± 0.06%/s; HSD + MEL: 0.21 ± 0.08%/s; p = 0.97) and TSI area under the curve (HSD + PL: 199899 ± 10,863 a.u.; HSD + MEL: 20315 ± 11,348 a.u.; p = 0.17) were similar at the end of each condition. Neither nitroxide molarity (HSD + PL: 7.8 × 10-5  ± 4.1 × 10-5 mol/L; HSD + MEL: 8.7 × 10-5  ± 5.1 × 10-5 mol/L; p = 0.55) nor free radical number (HSD + PL: 8.0 × 1015  ± 4.4 × 1015 ; HSD + MEL: 9.0 × 1015  ± 4.9 × 1015 ; p = 0.51) were different between conditions. Melatonin supplementation did not alter vascular function or ROS levels while on a HSD in this sample of young healthy normotensive adults.

Melatonin supplementation reduces nighttime blood pressure but does not affect blood pressure reactivity in normotensive adults on a high-sodium diet

High-sodium diets (HSDs) can cause exaggerated increases in blood pressure (BP) during physiological perturbations that cause sympathetic activation, which is related to cardiovascular risk. Melatonin supplementation has been shown to play a role in BP regulation. Our aim was to examine the effects of melatonin taken during an HSD on 24-h BP and BP reactivity during isometric handgrip (IHG) exercise, postexercise ischemia (PEI), and the cold pressor test (CPT). Twenty-two participants (11 men/11 women, 26.5 ± 3.1 yr, BMI: 24.1 ± 1.8 kg/m2, BP: 111 ± 9/67 ± 7 mmHg) were randomized to a 10-day HSD (6,900 mg sodium/day) that was supplemented with either 10 mg/day of melatonin (HSD + MEL) or placebo (HSD + PL). Twenty-four-hour ambulatory BP monitoring was assessed starting on day 9. Mean arterial pressure (MAP) was quantified during the last 30 s of IHG at 40% of maximal voluntary contraction and CPT, and during 3 min of PEI. Melatonin did not change 24-h MAP (HSD + PL: 83 ± 6 mmHg; HSD + MEL: 82 ± 5 mmHg; P = 0.23) but decreased nighttime peripheral (HSD + PL: 105 ± 10 mmHg; HSD + MEL: 100 ± 10 mmHg; P = 0.01) and central systolic BP (HSD + PL: 97 ± 9 mmHg; HSD + MEL: 93 ± 8 mmHg; P = 0.04) on the HSD compared with the HSD + PL. The absolute and percent change in MAP during IHG was not different between conditions (all P > 0.05). In conclusion, melatonin supplementation did not alter BP reactivity to the perturbations tested on an HSD but may be beneficial in lowering BP in young healthy normotensive adults.NEW & NOTEWORTHY BP reactivity was assessed during isometric handgrip (IHG) exercise, postexercise ischemia (PEI), and the cold pressor test (CPT) after 10 days of a high-sodium diet with and without melatonin supplementation. Melatonin did not alter BP reactivity in healthy normotensive men and women. However, melatonin did decrease nighttime peripheral and central systolic BP, suggesting it may be beneficial in lowering BP even in those with a normal BP.

Oxidative Stress in Health and Disease

Oxidative stress, resulting from the excessive intracellular accumulation of reactive oxygen species (ROS), reactive nitrogen species (RNS), and other free radical species, contributes to the onset and progression of various diseases, including diabetes, obesity, diabetic nephropathy, diabetic neuropathy, and neurological diseases, such as Alzheimer's disease (AD), amyotrophic lateral sclerosis (ALS), and Parkinson's disease (PD). Oxidative stress is also implicated in cardiovascular disease and cancer. Exacerbated oxidative stress leads to the accelerated formation of advanced glycation end products (AGEs), a complex mixture of crosslinked proteins and protein modifications. Relatively high levels of AGEs are generated in diabetes, obesity, AD, and other I neurological diseases. AGEs such as Ne-carboxymethyllysine (CML) serve as markers for disease progression. AGEs, through interaction with receptors for advanced glycation end products (RAGE), initiate a cascade of deleterious signaling events to form inflammatory cytokines, and thereby further exacerbate oxidative stress in a vicious cycle. AGE inhibitors, AGE breakers, and RAGE inhibitors are therefore potential therapeutic agents for multiple diseases, including diabetes and AD. The complexity of the AGEs and the lack of well-established mechanisms for AGE formation are largely responsible for the lack of effective therapeutics targeting oxidative stress and AGE-related diseases. This review addresses the role of oxidative stress in the pathogenesis of AGE-related chronic diseases, including diabetes and neurological disorders, and recent progress in the development of therapeutics based on antioxidants, AGE breakers and RAGE inhibitors. Furthermore, this review outlines therapeutic strategies based on single-atom nanozymes that attenuate oxidative stress through the sequestering of reactive oxygen species (ROS) and reactive nitrogen species (RNS).

Colorimetric sensing assay based on aptamer-gold nanoparticles for rapid detection of salivary melatonin to monitor circadian rhythm sleep disorders

Salivary melatonin is a clinically used biomarker for diagnosing circadian rhythm sleep disorders. Current melatonin detection assays are complex, expensive, and in many cases do not adequately measure low levels of salivary melatonin. Precisely measuring melatonin levels at multiple time points is crucial for determining dim light melatonin onset to evaluate its circadian fluctuation as well as the extent of circadian disruption and consequently adapt treatment regimens. Moreover, melatonin low levels in saliva challenges the reliability of routine clinical testing. This paper presents the development of a novel, highly sensitive, yet cost-effective, colorimetric assay for the rapid detection of salivary melatonin utilizing aptamer-AuNPs. Among several types of the aptamer tested, the 36-mer MLT-A-2 aptamer-AuNP probe showed the highest sensitivity with a melatonin limit of detection of 0.0011 nM along with a limit of quantification of 0.0021 nM in saliva. Moreover, our assay showed preferential interaction with melatonin when tested in presence of other structurally similar counter-targets. Taken together, this study provides new parameters for a melatonin assay that meets adequate levels of sensitivity and selectivity. The developed colorimetric assay could be adapted in a point-of-care system for profiling salivary melatonin levels at multiple time points during 24 h, crucial for accurately diagnosing and monitoring circadian rhythm sleep disorders and beyond.

The Role of the Circadian Rhythm in Dyslipidaemia and Vascular Inflammation Leading to Atherosclerosis

Cardiovascular diseases (CVD) are among the leading causes of death worldwide. Many lines of evidence suggest that the disturbances in circadian rhythm are responsible for the development of CVDs; however, circadian misalignment is not yet a treatable trait in clinical practice. The circadian rhythm is controlled by the central clock located in the suprachiasmatic nucleus and clock genes (molecular clock) located in all cells. Dyslipidaemia and vascular inflammation are two hallmarks of atherosclerosis and numerous experimental studies conclude that they are under direct influence by both central and molecular clocks. This review will summarise the results of experimental studies on lipid metabolism, vascular inflammation and circadian rhythm, and translate them into the pathophysiology of atherosclerosis and cardiovascular disease. We discuss the effect of time-respected administration of medications in cardiovascular medicine. We review the evidence on the effect of bright light and melatonin on cardiovascular health, lipid metabolism and vascular inflammation. Finally, we suggest an agenda for future research and recommend on clinical practice.

Shift Work and Metabolic Syndrome Updates: A Systematic Review

Shift work can cause circadian cycles disturbances and misaligns the endogenous rhythms. The physiological variables are driven by the circadian system and, its misalignment, can impair the metabolic functions. Thus, the main objective of this study was to evaluate the metabolic alterations as a result of shift work and night work reported in articles published in the last 5 years, using the eligibility criteria both gender and indexed articles in English language. In order to execute this work, we perform a systematic review according to PRISMA guidelines and searched about Chronobiology Disorders and Night Work, both related to metabolism, in Medline, Lilacs, ScienceDirect and Cochrane. Cross-sectional, cohort and experimental studies with low risk of bias were included. We found a total of 132 articles, and, after the selection process, 16 articles remained to be analyzed. It was observed that shift work can cause circadian misalignment and, consequently, some metabolic parameters alterations such as an impaired glycemic control and insulin functioning, cortisol phase release, cholesterol fractions imbalance, changes in morphological indexes and melatonin secretion. There are some limitations, such as heterogenicity in used databases and the 5 years restriction period, because the effects of sleep disturbance may have been reported earlier. In conclusion, we suggest that shift work interferes with the sleep-wake cycle and eating patterns, which cause crucial physiological alterations that, together, can lead to metabolic syndrome.

Impaired Melatonin Secretion, Oxidative Stress and Metabolic Syndrome in Night Shift Work

Metabolic syndrome has been associated in many studies with working in shifts. Even if the mechanistic details are not fully understood, forced sleep deprivation and exposure to light, as happens during night shifts, or irregular schedules with late or very early onset of the working program, lead to a sleep-wake rhythm misalignment, metabolic dysregulation and oxidative stress. The cyclic melatonin secretion is regulated by the hypothalamic suprachiasmatic nuclei and light exposure. At a central level, melatonin promotes sleep and inhibits wake-signals. Beside this role, melatonin acts as an antioxidant and influences the functionality of the cardiovascular system and of different metabolic processes. This review presents data about the influence of night shifts on melatonin secretion and oxidative stress. Assembling data from epidemiological, experimental and clinical studies contributes to a better understanding of the pathological links between chronodisruption and the metabolic syndrome related to working in shifts.

Glutathione system enhancement for cardiac protection: pharmacological options against oxidative stress and ferroptosis

The glutathione (GSH) system is considered to be one of the most powerful endogenous antioxidant systems in the cardiovascular system due to its key contribution to detoxifying xenobiotics and scavenging overreactive oxygen species (ROS). Numerous investigations have suggested that disruption of the GSH system is a critical element in the pathogenesis of myocardial injury. Meanwhile, a newly proposed type of cell death, ferroptosis, has been demonstrated to be closely related to the GSH system, which affects the process and outcome of myocardial injury. Moreover, in facing various pathological challenges, the mammalian heart, which possesses high levels of mitochondria and weak antioxidant capacity, is susceptible to oxidant production and oxidative damage. Therefore, targeted enhancement of the GSH system along with prevention of ferroptosis in the myocardium is a promising therapeutic strategy. In this review, we first systematically describe the physiological functions and anabolism of the GSH system, as well as its effects on cardiac injury. Then, we discuss the relationship between the GSH system and ferroptosis in myocardial injury. Moreover, a comprehensive summary of the activation strategies of the GSH system is presented, where we mainly identify several promising herbal monomers, which may provide valuable guidelines for the exploration of new therapeutic approaches.

Dietary Supplements Potentially Target Plasma Glutathione Levels to Improve Cardiometabolic Health in Patients with Diabetes Mellitus: A Systematic Review of Randomized Clinical Trials

Cardiovascular diseases (CVDs) continue to be the leading cause of death in people with diabetes mellitus. Severely suppressed intracellular antioxidant defenses, including low plasma glutathione (GSH) levels, are consistently linked with the pathological features of diabetes such as oxidative stress and inflammation. In fact, it has already been established that low plasma GSH levels are associated with increased risk of CVD in people with diabetes. Dietary supplements are widely used and may offer therapeutic benefits for people with diabetes at an increased risk of developing CVDs. However, such information remains to be thoroughly scrutinized. Hence, the current systematic review explored prominent search engines, including PubMed and Google Scholar, for updated literature from randomized clinical trials reporting on the effects of dietary supplements on plasma GSH levels in people with diabetes. Available evidence indicates that dietary supplements, such as coenzyme Q10, selenium, curcumin, omega-3 fatty acids, and vitamin E or D, may potentially improve cardiometabolic health in patients with diabetes. Such beneficial effects are related to enhancing plasma GSH levels and reducing cholesterol, including biomarkers of oxidative stress and inflammation. However, available evidence is very limited and additional clinical studies are still required to validate these findings, including resolving issues related to the bioavailability of these bioactive compounds.

Melatonin Supplement Plus Exercise Effectively Counteracts the Challenges of Isoproterenol-Induced Cardiac Injury in Rats

To explore the combined effects of exercise and melatonin supplement against the challenges of isoproterenol-induced cardiac oxidative stress and injury in rats., the expression of peroxisome proliferator-activated receptor gamma co-activator-1α (PGC-1α), mitochondrial biogenesis, and adenosine triphosphate (ATP) was up-regulated in cardiac muscle in normal rats and in a melatonin and exercise regimented group. Cardiac injury was induced by two subcutaneous injections of isoproterenol in the rats. The combination of exercise and melatonin supplement successfully counteracted the isoproterenol-induced cardiac injury, which is reflected by the improved hemodynamic parameters, reduction in oxidative stress markers, and cardiac injury serum markers (cardiac troponin-I and creatine kinase-MB). The cardiac tissue level of ATP, expression of PGC-1α and mitochondrial biogenesis-related genes, mitochondrial membrane potential, and the activities of typical antioxidants (glutathione, superoxide dismutase) were preserved, whereas the levels of reactive oxygen species, lipid peroxidation, and inflammatory cytokines were suppressed in the melatonin and exercise regimented (MEI) group compared to the group treated with isoproterenol alone. Furthermore, the expression of endoplasmic reticular stress- and apoptosis-related proteins (Bax, Bcl2, and caspase-3) was also effectively suppressed in the MEI group. Therefore, the present study suggests that melatonin supplement in combination with exercise prevents cardiac injury, possibly through the preservation of mitochondrial function and inhibition of oxidative stress in rats.

Lifestyle management in polycystic ovary syndrome - beyond diet and physical activity

Polycystic ovary syndrome (PCOS) is a common condition affecting reproductive-aged women with reproductive, metabolic and psychological consequences. Weight and lifestyle (diet, physical activity and behavioural) management are first-line therapy in international evidence-based guidelines for PCOS. While these recommend following population-level diet and physical activity guidelines, there is ongoing interest and research in the potential benefit of including psychological and sleep interventions, as well as a range of traditional, complimentary and integrative medicine (TCIM) approaches, for optimal management of PCOS. There is limited evidence to recommend a specific diet composition for PCOS with approaches including modifying protein, carbohydrate or fat quality or quantity generally having similar effects on the presentations of PCOS. With regards to physical activity, promising evidence supports the provision of vigorous aerobic exercise, which has been shown to improve body composition, cardiorespiratory fitness and insulin resistance. Psychological and sleep interventions are also important considerations, with women displaying poor emotional wellbeing and higher rates of clinical and subclinical sleep disturbance, potentially limiting their ability to make positive lifestyle change. While optimising sleep and emotional wellbeing may aid symptom management in PCOS, research exploring the efficacy of clinical interventions is lacking. Uptake of TCIM approaches, in particular supplement and herbal medicine use, by women with PCOS is growing. However, there is currently insufficient evidence to support integration into routine clinical practice. Research investigating inositol supplementation have produced the most promising findings, showing improved metabolic profiles and reduced hyperandrogenism. Findings for other supplements, herbal medicines, acupuncture and yoga is so far inconsistent, and to reduce heterogeneity more research in specific PCOS populations, (e.g. defined age and BMI ranges) and consistent approaches to intervention delivery, duration and comparators are needed. While there are a range of lifestyle components in addition to population-recommendations for diet and physical activity of potential benefit in PCOS, robust clinical trials are warranted to expand the relatively limited evidence-base regarding holistic lifestyle management. With consumer interest in holistic healthcare rising, healthcare providers will be required to broaden their knowledge pertaining to how these therapies can be safely and appropriately utilised as adjuncts to conventional medical management.

A cross-sectional study to correlate antioxidant enzymes, oxidative stress and inflammation with prevalence of hypertension

AIMS

Hypertension a multifactorial consequence of environmental factors, life style and genetics is the well-recognized risk factor contributing to coronary heart diseases. The antioxidant imbalance, excessive reactive oxygen species (ROS) leads to oxidative stress which is pivotal in progression of hypertension. The present study aims to understand the complex interaction between oxidative stress, inflammation and antioxidant system which is crucial to maintain cellular homeostasis which further can exaggerate hypertension pathophysiology.

MATERIALS AND METHODS

The metabolic profile of hypertensive and normotensive subjects from Malwa region, Punjab was compared by estimating lipid profile, cardiac, hepatic and renal markers. The oxidative stress markers (protein carbonyls and lipid peroxidation), inflammatory markers (Nitric oxide, Myeloperoxidase and advanced oxygen protein products), and antioxidant enzymes (Superoxide Dismutase, Catalase, and Total Antioxidant Capacity) were analyzed.

KEY FINDINGS

It is observed that the metabolic markers are altered in hypertensive subjects which further these subjects showed increased oxidative, inflammatory profile and compromised antioxidant status when compared with normotensive subjects. Co-relation analysis validated the involvement of inflammation and oxidative stress in impaired endothelial function and vital organ damage.

SIGNIFICANCE OF STUDY

These markers may act as early indicators of hypertension which usually do not show any physical symptoms, thus can be diagnosed and treated at the earliest. The current study suggests that disturbed homeostasis, a consequence of altered interaction between antioxidant system and inflammatory events raises the oxidative stress levels which eventually leads to hypertension and associated complications. These indicators can serve as early indicators of future chronic complications of hypertension.

The Therapeutic Strategies Targeting Mitochondrial Metabolism in Cardiovascular Disease

Cardiovascular disease (CVD) is a group of systemic disorders threatening human health with complex pathogenesis, among which mitochondrial energy metabolism reprogramming has a critical role. Mitochondria are cell organelles that fuel the energy essential for biochemical reactions and maintain normal physiological functions of the body. Mitochondrial metabolic disorders are extensively involved in the progression of CVD, especially for energy-demanding organs such as the heart. Therefore, elucidating the role of mitochondrial metabolism in the progression of CVD is of great significance to further understand the pathogenesis of CVD and explore preventive and therapeutic methods. In this review, we discuss the major factors of mitochondrial metabolism and their potential roles in the prevention and treatment of CVD. The current application of mitochondria-targeted therapeutic agents in the treatment of CVD and advances in mitochondria-targeted gene therapy technologies are also overviewed.

Redox Regulatory Changes of Circadian Rhythm by the Environmental Risk Factors Traffic Noise and Air Pollution

Significance: Risk factors in the environment such as air pollution and traffic noise contribute to the development of chronic noncommunicable diseases. Recent Advances: Epidemiological data suggest that air pollution and traffic noise are associated with a higher risk for cardiovascular, metabolic, and mental disease, including hypertension, heart failure, myocardial infarction, diabetes, arrhythmia, stroke, neurodegeneration, depression, and anxiety disorders, mainly by activation of stress hormone signaling, inflammation, and oxidative stress. Critical Issues: We here provide an in-depth review on the impact of the environmental risk factors air pollution and traffic noise exposure (components of the external exposome) on cardiovascular health, with special emphasis on the role of environmentally triggered oxidative stress and dysregulation of the circadian clock. Also, a general introduction on the contribution of circadian rhythms to cardiovascular health and disease as well as a detailed mechanistic discussion of redox regulatory pathways of the circadian clock system is provided. Future Directions: Finally, we discuss the potential of preventive strategies or "chrono" therapy for cardioprotection. Antioxid. Redox Signal. 37, 679-703.

Gut microbiota mediate melatonin signalling in association with type 2 diabetes

AIMS/HYPOTHESIS

It has been shown that melatonin plays a general beneficial role in type 2 diabetes in rodents but its role in humans is controversial. In the present study, we investigated the association between serum melatonin and type 2 diabetes risk in a southern Chinese population in a case-control study. We also examined the role of gut microbiota in this relationship.

METHODS

Individuals with type 2 diabetes (cases) and healthy individuals (controls) (n=2034) were recruited from a cross-sectional study and were matched for age and sex in a case-control study. The levels of serum melatonin were measured and the association between serum melatonin and type 2 diabetes risk was examined using a multivariable logistic regression model. We further conducted a rigorously matched case-control study (n=120) in which gut microbial 16S rRNA was sequenced and metabolites were profiled using an untargeted LC-MS/MS approach.

RESULTS

Higher levels of serum melatonin were significantly associated with a lower risk of type 2 diabetes (OR 0.82 [95% CI 0.74, 0.92]) and with lower levels of fasting glucose after adjustment for covariates (β -0.25 [95% CI -0.38, -0.12]). Gut microbiota exhibited alteration in the individuals with type 2 diabetes, in whom lower levels of serum melatonin, lower α- and β-diversity of gut microbiota (p<0.05), greater abundance of Bifidobacterium and lower abundance of Coprococcus (linear discriminant analysis [LDA] >2.0) were found. Seven genera were correlated with melatonin and type 2 diabetes-related traits; among them Bifidobacterium was positively correlated with serum lipopolysaccharide (LPS) and IL-10, whereas Coprococcus was negatively correlated with serum IL-1β, IL-6, IL-10, IL-17, TNF-α and LPS (Benjamini-Hochberg-adjusted p value [false discovery rate (FDR)] <0.05). Moreover, altered metabolites were detected in the participants with type 2 diabetes and there was a significant correlation between tryptophan (Trp) metabolites and the melatonin-correlated genera including Bifidobacterium and Coprococcus (FDR<0.05). Similarly, a significant correlation was found between Trp metabolites and inflammation factors, such as IL-1β, IL-6, IL-10, IL-17, TNF-α and LPS (FDR<0.05). Further, we showed that Trp metabolites may serve as a biomarker to predict type 2 diabetes status (AUC=0.804).

CONCLUSIONS/INTERPRETATION

A higher level of serum melatonin was associated with a lower risk of type 2 diabetes. Gut microbiota-mediated melatonin signalling was involved in this association; especially, Bifidobacterium- and Coprococcus-mediated Trp metabolites may be involved in the process. These findings uncover the importance of melatonin and melatonin-related bacteria and metabolites as potential therapeutic targets for type 2 diabetes.

Melatonin inhibits angiotensin II-induced atrial fibrillation through preventing degradation of Ang II Type I Receptor-Associated Protein (ATRAP)

Angiotensin II (Ang II) induced Atrial fibrillation (AF) often accompanied with reduced ATRAP which is a negative modulator of Ang II type 1 receptor (AT1R). Melatonin can protect against AF, but the underlying molecular mechanism remains poorly understood. In this study, Ang II was used to induce AF, and AF inducibility and duration were documented telemetrically. Ang II-infused mice had a higher AF incidence, which was associated with atrial fibrosis, inflammation, and oxidative stress. Melatonin partially inhibited these effects, and enforced expression of siRNA-ATRAP in atria counteracted the beneficial role of melatonin. Specifically, melatonin inhibited expression of Ang II-induced proteasome and immunoproteasome subunits β2, β2i, β5, and β5i as well as their corresponding trypsin-like and chymotrypsin-like activities and blocked ATRAP degradation. In turn, this inhibited AT1R-mediated NF-κB signaling, transforming growth factor (TGF)-β1/Smad signaling in the atria, and thereby affected atrial remodeling and AF. Melatonin receptor inhibition by the chemical inhibitor luzindole partially inhibited the inhibitory effects of melatonin on proteasome activity and also Ang II-induced pathological changes in the atria. Overall, our study demonstrates that melatonin protects against Ang II-induced AF by inhibiting proteasome activity and stabilizing ATRAP expression, and these effects are partially dependent on melatonin receptor activation.

Nutritional Supplements and Complementary Therapies in Polycystic Ovary Syndrome

Polycystic ovary syndrome (PCOS) affects 1 in 5 women of reproductive age, and is characterized by menstrual irregularities, clinical or biochemical hyperandrogenism, and the presence of polycystic ovary morphology. One of the recommended treatment strategies in the international evidence-based guidelines is lifestyle modification, which includes diet and exercise, with the aim of improving a range of health outcomes. The incurable nature of PCOS reinforces the importance of developing novel and innovative symptomatic relief strategies, which are currently the only available approaches for improving quality of life for these women. Women with PCOS tend to be nutrient deficient in many common vitamins and minerals, thought to be associated with the psychological (depression, anxiety, etc.) and physiological (insulin resistance, diabetes, infertility, etc.) sequelae of the condition. Nutrient supplementation and the integration of complementary medicine as adjuncts to traditional lifestyle-based therapies in PCOS could therefore provide additional benefits to these women. In this review, we synthesize the evidence regarding nutrient supplementation and complementary therapies in PCOS, predominantly from randomized controlled trials, systematic reviews, and meta-analyses, to provide an overview of the state of knowledge in this field. The evidence to date suggests that specific vitamins (B-12, inositols, folate, vitamins D, E, and K), vitamin-like nutrients (bioflavonoids and α-lipoic acid), minerals (calcium, zinc, selenium, and chromium picolinate), and other formulations (melatonin, ω-3 fatty acids, probiotics, and cinnamon), as well as some complementary approaches such as acupuncture and yoga may be beneficial in PCOS. However, there remain areas of uncertainty and key limitations in the literature that must be overcome before these therapies can be integrated into routine clinical practice.

Effects of melatonin supplementation in patients with type 2 diabetes mellitus and chronic periodontitis under nonsurgical periodontal therapy: A double-blind randomized controlled trial

BACKGROUND

The aim of the present study was to investigate the effects of melatonin supplementation along with nonsurgical periodontal therapy (NSPT) in patients with type 2 diabetes mellitus (T2DM) and chronic periodontitis (CP).

MATERIALS AND METHODS

The present study was a double-blind clinical trial. Fifty diabetic patients with periodontitis were randomly allocated to control (n = 25) and intervention groups (n = 25). Two tablets of 250 mg melatonin (6 mg net melatonin) or placebo were received by the intervention or control groups once a day for 8 weeks. Fasting blood glucose (FBG), glycosylated hemoglobin levels (HbA1c), lipid profile, systolic and diastolic blood pressure (SBP and DBP), anthropometric indices including weight, waist and hip circumference (WC and HC), and body mass index (BMI) were measured in patients at the beginning and end of the intervention.

RESULTS

Forty-four patients (22 patients in each group) completed the study. In the intervention group, a significant reduction was observed in HbA1c (P = 0.004), weight, BMI, WC, HC (all P < 0.001), DBP (P = 0.017), and SBP (P = 0.006). The high-density lipoprotein-cholesterol was significantly increased in the intervention group after the intervention (P = 0.007). Moreover, after the adjustment of confounding factors, the mean changes of HbA1c (mean difference: -1.30, confidence interval [CI]: -2.41--0.19, P = 0.02), weight (mean difference: -3.90, CI: -5.30-2.50, P < 0.001), WC (mean difference: -1.37, CI: -2.19--0.55, P = 0.002), BMI (mean difference: -1.41, CI: -1.92--0.89, P < 0.001), HC (mean difference: -3.55, CI: -4.74--2.35, P < 0.001), and SBP (mean difference: -1.24, CI: -2.41--0.06, P = 0.03) improved significantly in the intervention group by comparison with the control group. No side effects were reported during the study.

CONCLUSION

The adjunct therapy of NSPT and melatonin may be useful in controlling the glycemic index, lipid profile, BP, and weight in T2DM with CP.

Role of Oxidative Stress in the Pathogenesis of Atherothrombotic Diseases

Oxidative stress is generated by the imbalance between reactive oxygen species (ROS) formation and antioxidant scavenger system’s activity. Increased ROS, such as superoxide anion, hydrogen peroxide, hydroxyl radical and peroxynitrite, likely contribute to the development and complications of atherosclerotic cardiovascular diseases (ASCVD). In genetically modified mouse models of atherosclerosis, the overexpression of ROS-generating enzymes and uncontrolled ROS formation appear to be associated with accelerated atherosclerosis. Conversely, the overexpression of ROS scavenger systems reduces or stabilizes atherosclerotic lesions, depending on the genetic background of the mouse model. In humans, higher levels of circulating biomarkers derived from the oxidation of lipids (8-epi-prostaglandin F_2α, and malondialdehyde), as well as proteins (oxidized low-density lipoprotein, nitrotyrosine, protein carbonyls, advanced glycation end-products), are increased in conditions of high cardiovascular risk or overt ASCVD, and some oxidation biomarkers have been reported as independent predictors of ASCVD in large observational cohorts. In animal models, antioxidant supplementation with melatonin, resveratrol, Vitamin E, stevioside, acacetin and n-polyunsaturated fatty acids reduced ROS and attenuated atherosclerotic lesions. However, in humans, evidence from large, placebo-controlled, randomized trials or prospective studies failed to show any athero-protective effect of antioxidant supplementation with different compounds in different CV settings. However, the chronic consumption of diets known to be rich in antioxidant compounds (e.g., Mediterranean and high-fish diet), has shown to reduce ASCVD over decades. Future studies are needed to fill the gap between the data and targets derived from studies in animals and their pathogenetic and therapeutic significance in human ASCVD.

The Role of Melatonin in Chronic Kidney Disease and Its Associated Risk Factors: A New Tool in Our Arsenal?

BACKGROUND

The increasing incidence of chronic kidney disease (CKD), as a consequence of the high prevalence of arterial hypertension and type 2 diabetes mellitus (T2DM), warrants the need for developing effective treatment approaches. In this regard, the pineal gland-derived hormone melatonin may represent an appealing treatment approach of CKD and its associated risk factors.

SUMMARY

Targeting the adverse pathophysiology surrounding CKD and its associated risk factors has been the concept of pharmacologic treatment developed for its management. This review article aimed to present the role of melatonin in this direction, by providing an overview of melatonin's physiology followed by its effect as a therapeutic agent in arterial hypertension and T2DM.

KEY MESSAGES

Melatonin, the primary darkness hormone, possesses pleiotropic mechanisms of action which may have important implications in various pathologic states since its receptors are situated across various organ systems. As a treatment tool in arterial hypertension, melatonin may be efficacious in reducing both daytime and nocturnal blood pressure by influencing endothelial function, oxidative stress, the autonomic nervous system, and the renin-angiotensin system. Melatonin may also increase insulin sensitivity and β-cell function. However, late meal intake may be detrimental in glucose regulation, as consumption close to melatonin peak concentrations may induce hyperglycemia and insulin resistance. This finding may explain the inconsistent glycose regulation achieved with melatonin in clinical trials and meta-analyses. Additionally, the presence of genetic variants to melatonin receptor 2 may predispose to T2DM development. Finally, we present the available preclinical evidence supporting melatonin's efficacy in ameliorating CKD's pathophysiology since melatonin supplementation has not been adequately explored in patients with CKD. The combined use of stem cells with melatonin is an appealing therapeutic approach which ought to be assessed further.

Evidence for the Benefits of Melatonin in Cardiovascular Disease

The pineal gland is a neuroendocrine gland which produces melatonin, a neuroendocrine hormone with critical physiological roles in the circadian rhythm and sleep-wake cycle. Melatonin has been shown to possess anti-oxidant activity and neuroprotective properties. Numerous studies have shown that melatonin has significant functions in cardiovascular disease, and may have anti-aging properties. The ability of melatonin to decrease primary hypertension needs to be more extensively evaluated. Melatonin has shown significant benefits in reducing cardiac pathology, and preventing the death of cardiac muscle in response to ischemia-reperfusion in rodent species. Moreover, melatonin may also prevent the hypertrophy of the heart muscle under some circumstances, which in turn would lessen the development of heart failure. Several currently used conventional drugs show cardiotoxicity as an adverse effect. Recent rodent studies have shown that melatonin acts as an anti-oxidant and is effective in suppressing heart damage mediated by pharmacologic drugs. Therefore, melatonin has been shown to have cardioprotective activity in multiple animal and human studies. Herein, we summarize the most established benefits of melatonin in the cardiovascular system with a focus on the molecular mechanisms of action.

The effects of melatonin administration on carotid intima-media thickness and pulse wave velocity in diabetic nephropathy: A randomized, double-blind, placebo-controlled trial

BACKGROUND

Previous studies have reported that melatonin intake is inversely associated with reduced markers of atherosclerosis development such as carotid intima-media thickness (CIMT).

OBJECTIVE

This study was designed to assess the effects of melatonin administration on CIMT and pulse wave velocity (PWV) in patients with diabetic nephropathy (DN).

MATERIALS AND METHODS

This randomized, double-blind, placebo-controlled trial was conducted on 32 DN patients. Subjects were assigned to receive melatonin or placebo (starch) for 24 weeks. Individuals in the melatonin group (n = 19) received 10 mg/day. CIMT and PWV levels were taken at the study baseline and after 24 weeks of intervention.

RESULTS

After 24 weeks of intervention, melatonin intake did not affect mean levels of left (P = 0.51) and right (P = 0.16) CIMT and maximum levels of left (P = 0.76) and right (P = 0.15) CIMT, and PWV (P = 0.55) compared with the placebo. In addition, within-group difference demonstrated a significant reduction in mean levels of right CIMT (P = 0.01) in the melatonin group. We did not observe any significant change in C-reactive protein (CRP) concentrations after melatonin intake (P = 0.81).

CONCLUSIONS

Melatonin intake did not affect mean levels of left and right CIMT and maximum levels of left and right CIMT, PWV, CRP levels compared with the placebo. In addition, within-group difference demonstrated a significant reduction in mean levels of right CIMT in the melatonin group. This trial was registered at www.irct.ir as http://www.irct.ir: IRCT20200527047584N2.

Evaluation of Melatonin Therapy in Patients with Myocardial Ischemia-Reperfusion Injury: A Systematic Review and Meta-Analysis

Objectives

We conducted a meta-analysis to quantitatively evaluate the effect of melatonin therapy on patients with myocardial ischemia-reperfusion injury (MIRI) and explore the influencing factors.

Background

Although preclinical studies have shown that melatonin can alleviate MIRI, its protective effect on MIRI in patients remains controversial.

Methods

We searched PubMed, the Cochrane Library, and Embase. The primary outcome was cardiac function (left ventricular ejection fraction [LVEF], left ventricular end-diastolic volume [LVEDV], and left ventricular end-systolic volume [LVESV]) and myocardial infarct parameters (total left ventricular mass and infarct size).

Results

We included nine randomized controlled clinical trials with 631 subjects. Our results showed that melatonin had no significant effects on the primary outcome, but subgroup analyses indicated that when melatonin was administered by intravenous and intracoronary injection at the early stage of myocardial ischemia, LVEF was improved (<3.5 h; standardized mean difference [SMD]:0.50; 95% CI: 0.06 to 0.94; P = 0.03) and the infarct size was reduced (<2.5 h, SMD: −0.86; 95% CI: −1.51 to −0.22; P = 0.01), whereas when melatonin was injected at the late stage of myocardial ischemia (≥3.5 h or 2.5 h), the results were the opposite. Furthermore, melatonin intervention reduced the level of cardiac injury markers, inflammatory cytokines, oxidation factors, and increased the level of antioxidant factors (P < 0.001).

Conclusions

The results indicated that the cardioprotective function of melatonin for MIRI was influenced by the route and timing regimen of melatonin administration; the mechanism of which may be associated with the production of inflammatory cytokines, the balance of oxidation, and antioxidant factors.

Safety of higher doses of melatonin in adults: A systematic review and meta-analysis

Melatonin is commonly used for sleep and jetlag at low doses. However, there is less documentation on the safety of higher doses, which are being increasingly used for a wide variety of conditions, including more recently COVID-19 prevention and treatment. The aim of this review was to investigate the safety of higher doses of melatonin in adults. Medline, Scopus, Embase and PsycINFO databases from inception until December 2019 with convenience searches until October 2020. Randomised controlled trials investigating high-dose melatonin (≥10 mg) in human adults over 30 years of age were included. Two investigators independently abstracted articles using PRISMA guidelines. Risk of bias was assessed by a committee of three investigators. 79 studies were identified with a total of 3861 participants. Studies included a large range of medical conditions. The meta-analysis was pooled data using a random effects model. The outcomes examined were the number of adverse events (AEs), serious adverse events (SAEs) and withdrawals due to AEs. A total of 29 studies (37%) made no mention of the presence or absence of AEs. Overall, only four studies met the pre-specified low risk of bias criteria for meta-analysis. In that small subset, melatonin did not cause a detectable increase in SAEs (Rate Ratio = 0.88 [0.52, 1.50], p = .64) or withdrawals due to AEs (0.93 [0.24, 3.56], p = .92), but did appear to increase the risk of AEs such as drowsiness, headache and dizziness (1.40 [1.15, 1.69], p < .001). Overall, there has been limited AE reporting from high-dose melatonin studies. Based on this limited evidence, melatonin appears to have a good safety profile. Better safety reporting in future long-term trials is needed to confirm this as our confidence limits were very wide due to the paucity of suitable data.

Effects of Melatonin and Propolis Supplementation on Inflammation, Oxidative Stress, and Clinical Outcomes in Patients with Primary Pneumosepsis: A Randomized Controlled Clinical Trial

Background & Objective: The present study aimed to investigate the effects of propolis and melatonin supplementation on inflammation, clinical outcomes, and oxidative stress markers in patients with primary pneumosepsis. Materials and Methods: This pilot randomized controlled trial was conducted on 55 patients with primary pneumosepsis who were randomly assigned to the intervention and control groups. In the three intervention groups, the patients received propolis alone (1,000 mg/day), propolis (1,000 mg/day) plus melatonin (20 mg/day), and melatonin alone (20 mg/day). The control group received placebo. The inflammatory and oxidative stress markers as well as clinical outcomes were evaluated before and after the intervention, and the 28-day survival rate was also recorded. Results: After the intervention, the combination of propolis and melatonin significantly reduced interleukin-6 (-55.282 pg/ml ) and C-reactive protein (-21.656 mg/l ) levels, while increasing gavage intake (326.680 ml/day ) and improving some clinical outcomes (APACHE II, SOFA and NUTRIC scores) compared to control group. However, no significant difference was observed between the groups in terms of oxidative stress and hematological indices. In addition, the 28-day survival rate had no significant difference between the groups (P=0.07). Conclusion: Supplementation with propolis and melatonin may improve clinical outcomes by reducing inflammation. Further investigations are required to confirm these findings.

New insights into the role of melatonin in diabetic cardiomyopathy

Diabetic cardiovascular complications and impaired cardiac function are considered to be the main causes of death in diabetic patients worldwide, especially patients with type 2 diabetes mellitus (T2DM). An increasing number of studies have shown that melatonin, as the main product secreted by the pineal gland, plays a vital role in the occurrence and development of diabetes. Melatonin improves myocardial cell metabolism, reduces vascular endothelial cell death, reverses microcirculation disorders, reduces myocardial fibrosis, reduces oxidative and endoplasmic reticulum stress, regulates cell autophagy and apoptosis, and improves mitochondrial function, all of which are the characteristics of diabetic cardiomyopathy (DCM). This review focuses on the role of melatonin in DCM. We also discuss new molecular findings that might facilitate a better understanding of the underlying mechanism. Finally, we propose potential new therapeutic strategies for patients with T2DM.

The association of oxidative stress biomarkers with type 2 diabetes mellitus: A systematic review and meta-analysis

BACKGROUND AND AIMS

Oxidative stress plays a major role in the development of type 2 diabetes mellitus (T2DM). However, there were controversial outcomes in the literature between the association of oxidative stress biomarkers and T2DM. The purpose of this systematic review and meta-analysis was to critically examine the association of oxidative stress biomarkers with T2DM.

METHODS

We systematically searched different electronic databases including PubMed/Medline, EMBASE, ScienceDirect, Web of Science, and Cochrane Library to find the relevant studies up to May 2021. The pooled standard mean difference (SMD) with a 95% confidence interval (CI) was used to define the variation between the study groups.

RESULTS

A total of 22 case-control studies with 2853 subjects (1667 diabetic patients and 1186 healthy controls) were found to be eligible for this meta-analysis. The pooled results of meta-analysis showed a significant difference in the levels malondialdehyde (SMD [95% CI]: 2.27 [1.62, 2.91]), nitric oxide (SMD [95% CI]: 1.40 [0.00, 2.81]), glutathione (SMD [95% CI]: -1.76 [-2.94, -0.59]), and total antioxidant status (SMD [95% CI]: -1.40 [-2.28, -0.51]) between the patient group and healthy subjects, whereas no significant difference was observed in the superoxide dismutase levels (SMD [95% CI]: -1.20 [-2.55, 0.15]) and glutathione peroxidase levels (SMD [95% CI]: 0.07 [-2.80, 2.94]).

CONCLUSION

The present analysis suggests that oxidative stress might have a potential role in the pathogenesis of T2DM in humans. However, further studies should be needed to elucidate the possible mechanism and strengthen this evidence.

Effects of daily administration of melatonin before bedtime on fasting insulin, glucose and insulin sensitivity in healthy adults and patients with metabolic diseases. A systematic review and meta-analysis

BACKGROUND

Melatonin is increasingly used as a pharmacological sleep aid but it is also emerging as a regulator of glucose homoeostasis. Yet, previous research has been ambiguous with reports of both positive and negative effects of melatonin on glucose metabolism.

OBJECTIVES

To assess the effect of daily treatment with melatonin on fasting glucose, insulin, insulin sensitivity and haemoglobin A1c (HbA1c) levels.

DATA SOURCES

MEDLINE, EMBASE, CENTRAL, clinicaltrials.gov and clinicaltrialsregister.eu were systematically searched.

ELIGIBILITY CRITERIA, PARTICIPANTS AND INTERVENTIONS

All randomized, placebo-controlled studies with melatonin treatment were assessed. We included studies with daily melatonin treatment (≥2 weeks) of healthy adults or patients with metabolic diseases.

METHODS

Hedges' g differences were calculated for the metabolic parameters of the included studies, heterogeneity was assessed with χ² and I² tests and meta-analyses were performed with the random-effects model.

RESULTS

Long-term treatment with melatonin did not change fasting glucose significantly compared with placebo (g: -0.07 [-0.22 to 0.08], n = 603) but it reduced fasting insulin levels slightly (g: -0.27 [-0.50 to -0.04], n = 278) and trended towards reduced insulin resistance (HOMA-IR) (g: -0.20 [-0.44 to 0.03], n = 278). HbA1c levels were largely unaffected by melatonin treatment compared with placebo (g: 0.14 [-0.19 to 0.46], n = 142).

CONCLUSIONS

With the available literature, melatonin seems to be a glucose-metabolic safe sleep aid in patients with metabolic diseases and in healthy adults. It may even have beneficial glucose-metabolic effects as fasting insulin levels were reduced in this meta-analysis, but the confidence intervals of the meta-analyses are wide, underscoring the need for further research within this field.

Melatonin supplementation and anthropometric indicators of obesity: A systematic review and meta-analysis

OBJECTIVE

According to in vivo and in vitro studies, melatonin appears to be a potential supplement for obesity reduction. The aim of this study was to review the literature on randomized clinical trials that evaluated the effects of melatonin supplementation on anthropometric indicators of obesity in humans.

METHODS

We conducted a systematic review with meta-analysis in the following databases: Pubmed, LILACS, Scielo, Scopus, Web of Science, Cochrane, and Embase. We included studies that evaluated melatonin supplementation's effects, compared with placebo, on anthropometric measures, including body weight, body mass index (BMI), and waist circumference, in people ≥18 y of age. This systematic review and meta-analysis were registered on PROSPERO: CRD42021241079.

RESULTS

Of the 23 studies included, 11 showed significant results from melatonin supplementation on weight loss, BMI, or waist circumference, compared with placebo. In the meta-analysis, melatonin supplementation significantly reduced body weight (standardized mean difference, -0.48; 95% confidence interval, -0.94 to -0.02; P = <0.01; I² = 92%). Results for BMI and waist circumference were null. The I² tests were significant for the analyses with significant results.

CONCLUSION

The results demonstrated that melatonin supplementation was responsible for significantly reducing body weight. More studies are needed before melatonin can be recommended for weight loss.

Implications for Systemic Approaches to COVID-19: Effect Sizes of Remdesivir, Tocilizumab, Melatonin, Vitamin D3, and Meditation

INTRODUCTION

COVID-19 poses a chronic threat to inflammatory systems, reinforcing the need for efficient anti-inflammatory strategies. The purpose of this review and analysis was to determine the efficacy of various interventions upon the inflammatory markers most affected by COVID-19. The focus was on the markers associated with COVID-19, not the etiology of the virus itself.

METHODS

Based on 27 reviewed papers, information was extracted on the effects of COVID-19 upon inflammatory markers, then the effects of standard treatments (Remdesivir, Tocilizumab) and adjunctive interventions (vitamin D3, melatonin, and meditation) were extracted for those markers. These data were used to approximate effect sizes for the disease or interventions via standardized mean differences (SMD).

RESULTS

The data that were available indicated that adjunctive interventions affected 68.4% of the inflammatory markers impacted by COVID-19, while standard pharmaceutical medication affected 26.3%.

DISCUSSION

Nonstandard adjunctive care appeared to have comparable or superior effects in comparison to Remdesivir and Tocilizumab on the inflammatory markers most impacted by COVID-19. Alongside standards of care, melatonin, vitamin D3, and meditation should be considered for treatment of SARS-COV-2 infection and COVID-19 disease.

Effects of Melatonin Supplementation on Insulin Levels and Insulin Resistance: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Insulin resistance (IR) is a pivotal process in various metabolic diseases. The well-known treatment is lifestyle modification and medication therapy, which may result in poor compliance and side effects. Melatonin has been suggested to have a role in glucose metabolism, yet the results across studies have been inconsistent. Therefore, we performed a systematic review to evaluate the effects of melatonin supplementation on insulin levels and IR. We searched PubMed, Embase, Cochrane Central Register of Controlled Trials, and ClinicalTrials.gov, and identified randomized controlled trials (RCTs) published prior to August 2020. Articles were reviewed, selected and extracted by two reviewers independently. In total, 8 RCTs of 376 participants were included. Data were pooled using a random-effects model, with mean differences (MDs) and 95% confidence intervals (CIs). Our results showed that melatonin administration significantly reduced insulin levels and homeostasis model assessment of insulin resistance (HOMA-IR), and increased the quantitative insulin sensitivity check index (QUICKI). We conclude that melatonin ameliorated hyperinsulinemia, insulin resistance, and insulin sensitivity, and the results are an update of a previous meta-analysis. Although more investigations are required, we clearly provide evidence for the use of melatonin as an adjuvant treatment for metabolic disorders involving IR.

Melatonin as a Trigger of Therapeutic Bone Regenerating Capacity in Biomaterials

Bone defects are usually treated with bone grafting. Several synthetic biomaterials have emerged to replace autologous and allogeneic bone grafts, but there are still shortcomings in bone regeneration. Melatonin has demonstrated a beneficial effect on bone metabolism with the potential to treat fractures, bone defects, and osteoporosis. The hormone promoted osteogenesis, inhibited osteoclastogenesis, stimulated angiogenesis, and reduced peri-implantitis around the graft. Recently, a growing number of studies showed beneficial effects of melatonin to treat bone defects. However, cellular and molecular mechanisms involved in bone healing are still poorly understood. In this review, we recapitulate the potential mechanisms of melatonin, providing a new horizon to the clinical treatment of bone defects.

Effects of melatonin supplementation on serum oxidative stress markers and disease activity in systemic lupus erythematosus patients: A randomised, double-blind, placebo-controlled trial

BACKGROUND

Considering pathological significance of oxidative stress in systemic lupus erythematosus (SLE), current research aimed to evaluate the effects of melatonin supplementation on oxidative stress markers and disease activity in SLE.

METHOD

In this randomised double-blind, placebo-controlled trial, 32 SLE females were selected and randomly assigned into two groups to take 10 mg/day melatonin or placebo for 12 weeks. Before and after trial, serum malondialdehyde (MDA) and total antioxidant capacity (TAC) were measured and disease activity was determined by Systemic lupus erythematosus disease activity index 2000 (SLEDAI-2K).

RESULTS

Twenty-five patients (13 in the melatonin and 12 in the placebo groups) completed the trial. Melatonin supplementation caused significant reduction in serum MDA compared with baseline (P = .003) and placebo group (P = .004). Serum TAC level did not change significantly in the melatonin group compared with baseline and placebo group (P > .05). Furthermore, melatonin supplementation did not cause significant change in disease activity compared to baseline and placebo group (P > .05).

CONCLUSION

This study demonstrated affirmative effects of melatonin in decreasing oxidative stress in SLE patients without any effect on disease activity. Further investigations are required to affirm these primitive findings and to achieve concise conclusions.What's known Free radical damage and oxidative stress has a remarkable function in systemic lupus erythematosus (SLE) pathogenesis. Products derived from oxidative modification cascades are found in biological fluids and their redundancy has a correlation with disease activity and organ damage in SLE. Dietary supplements, which decrease oxidative stress, would be useful in managing SLE. Melatonin is a potent antioxidant and has anti-inflammatory and immunomodulatory characteristics. Limited in vitro and animal studies are available indicating desirable effects of melatonin in preventing from SLE organ damage, thereby opening a new area of investigation that can contribute to using melatonin as a therapy or co-therapy for SLE. What's new Melatonin supplementation caused significant reduction in serum MDA compared with baseline and placebo group. Serum TAC level did not change significantly in the melatonin group compared with baseline and placebo group. Furthermore, melatonin supplementation did not cause significant change in disease activity compared to baseline and placebo group.

Effects of melatonin supplementation on diabetes: A systematic review and meta-analysis of randomized clinical trials

BACKGROUND & AIMS

Melatonin appears as a supplement capable of helping with diabetes. However, there is no evidence from meta-analyses that showed significant results in insulin resistance and glycated hemoglobin. This study aimed to review the literature on randomized clinical trials that evaluated melatonin supplementation effects, compared to placebo, on diabetes parameters in humans.

METHODS

We conducted a systematic review and meta-analysis in the following databases: Pubmed, LILACS, Scielo, Scopus, Web of Science, Cochrane, and Embase. We included randomized clinical trials investigating melatonin supplementation's effects, compared to placebo, on fasting blood glucose, insulin resistance, and glycated hemoglobin. Non-randomized clinical trials, observation studies, and animal models were excluded. The Cochrane scale assessed the quality of the studies. We conducted a meta-analysis on fasting blood glucose, insulin resistance, and glycated hemoglobin.

RESULTS

Sixteen studies were included, of which 56% showed benefits from supplementation with melatonin in diabetes parameters compared with placebo. Our meta-analysis showed significant results for fasting blood glucose [mean difference: -4.65; 95% CI: -8.06, -1.23; p = < 0.01; I² = 58%], glycated hemoglobin [mean difference: -0.38; 95% CI: -0.67, -0.10; p = 0.30; I² = 18%], and insulin resistance [mean difference: -0.58; 95% CI: -1.00, -0.15; p = 0.17; I² = 35%].

CONCLUSIONS

Our results showed that melatonin supplementation was useful for reducing diabetes parameters when compared to placebo.