-
Frontiers in Cell and Developmental... 2023Spinal cord injury (SCI) is a sudden onset of disruption to the spinal neural tissue, leading to loss of motor control and sensory function of the body. Oxidative stress... (Review)
Review
Spinal cord injury (SCI) is a sudden onset of disruption to the spinal neural tissue, leading to loss of motor control and sensory function of the body. Oxidative stress is considered a hallmark in SCI followed by a series of events, including inflammation and cellular apoptosis. Melatonin was originally discovered as a hormone produced by the pineal gland. The subcellular localization of melatonin has been identified in mitochondria, exhibiting specific onsite protection to excess mitochondrial reactive oxygen species and working as an antioxidant in diseases. The recent discovery regarding the molecular basis of ligand selectivity for melatonin receptors and the constant efforts on finding synthetic melatonin alternatives have drawn researchers' attention back to melatonin. This review outlines the application of melatonin in SCI, including 1) the relationship between the melatonin rhythm and SCI in clinic; 2) the neuroprotective role of melatonin in experimental traumatic and ischemia/reperfusion SCI, i.e., exhibiting anti-oxidative, anti-inflammatory, and anti-apoptosis effects, facilitating the integrity of the blood-spinal cord barrier, ameliorating edema, preventing neural death, reducing scar formation, and promoting axon regeneration and neuroplasticity; 3) protecting gut microbiota and peripheral organs; 4) synergizing with drugs, rehabilitation training, stem cell therapy, and biomedical material engineering; and 5) the potential side effects. This comprehensive review provides new insights on melatonin as a natural antioxidant therapy in facilitating rehabilitation in SCI.
PubMed: 37691830
DOI: 10.3389/fcell.2023.1218553 -
Life Sciences May 2024Melatonin, a potent antioxidant and free radical scavenger, has been demonstrated to be effective in gynecological conditions and female reproductive cancers. This... (Review)
Review
Melatonin, a potent antioxidant and free radical scavenger, has been demonstrated to be effective in gynecological conditions and female reproductive cancers. This review consolidates the accumulating evidence on melatonin's multifaceted protective effects in different pathological contexts. In gynecological conditions such as endometriosis, polycystic ovary syndrome (PCOS), and uterine leiomyoma, melatonin has shown promising effects in reducing oxidative stress, inflammation, and hormonal imbalances. It inhibits adhesion molecules' production, and potentially mitigates leukocyte adherence and inflammatory responses. Melatonin's regulatory effects on hormone production and insulin sensitivity in PCOS individuals make it a promising candidate for improving oocyte quality and menstrual irregularities. Moreover, melatonin exhibits significant antitumor effects by modulating various signaling pathways, promoting apoptosis, and suppressing metastasis in breast cancers and gynecological cancers, including ovarian, endometrial, and cervical cancers. Furthermore, melatonin's protective effects are suggested to be mediated by interactions with its receptors, estrogen receptors and other nuclear receptors. The regulation of clock-related genes and circadian clock systems may also contribute to its inhibitory effects on cancer cell growth. However, more comprehensive research is warranted to fully elucidate the underlying molecular mechanisms and establish melatonin as a potential therapeutic agent for these conditions.
Topics: Humans; Female; Melatonin; Polycystic Ovary Syndrome; Antioxidants; Oxidative Stress; Breast Neoplasms
PubMed: 38479596
DOI: 10.1016/j.lfs.2024.122557 -
Free Radical Biology & Medicine Nov 2023Ferroptosis is a novel form of cell death that plays a critical role in the pathological and physiological processes of early brain injury following subarachnoid...
Ferroptosis is a novel form of cell death that plays a critical role in the pathological and physiological processes of early brain injury following subarachnoid hemorrhage. Melatonin, as the most potent endogenous antioxidant, has shown strong protective effects against pathological changes following subarachnoid hemorrhage, but its impact on ferroptosis induced by subarachnoid hemorrhage remains unexplored. In our study, we established a subarachnoid hemorrhage model in male SD rats. We found that subarachnoid hemorrhage induced changes in ferroptosis-related indicators such as lipid peroxidation and iron metabolism, while intraperitoneal injection of melatonin (40 mg/kg) effectively ameliorated these changes to a certain degree. Moreover, in a subset of rats with subarachnoid hemorrhage who received pre-treatment via intravenous injection of the melatonin receptor antagonist Luzindole (1 mg/kg) and 4P-PDOT (1 mg/kg), we found that the protective effect of melatonin against subarachnoid hemorrhage includes inhibition of lipid peroxidation and reduction of iron accumulation depended on melatonin receptor 1B (MT2). Furthermore, our study demonstrated that melatonin inhibited neuronal ferroptosis by activating the NRF2 signaling pathway, as evidenced by in vivo inhibition of NRF2. In summary, melatonin acts through MT2 and activates NRF2 and downstream genes such as HO-1/NQO1 to inhibit ferroptosis in subarachnoid hemorrhage-induced neuronal injury, thereby improving neurological function in rats. These results suggest that melatonin is a promising therapeutic target for subarachnoid hemorrhage.
Topics: Rats; Male; Animals; Melatonin; Ferroptosis; NF-E2-Related Factor 2; Rats, Sprague-Dawley; Receptors, Melatonin; Subarachnoid Hemorrhage; Brain Injuries; Iron
PubMed: 37717795
DOI: 10.1016/j.freeradbiomed.2023.09.012 -
Aging Clinical and Experimental Research Nov 2023The prophylactic effect of exogenous melatonin and melatonin receptor agonists (MMRAs) on postoperative delirium (POD) in elderly patients remains controversial. (Meta-Analysis)
Meta-Analysis Review
Prophylactic effect of exogenous melatonin and melatonin receptor agonists on postoperative delirium in elderly patients: a systemic review and meta-analysis of randomized controlled trials.
BACKGROUND
The prophylactic effect of exogenous melatonin and melatonin receptor agonists (MMRAs) on postoperative delirium (POD) in elderly patients remains controversial.
OBJECTIVE
This study aimed to assess the prophylactic effect of MMRAs on POD by conducting a systemic review and meta-analysis of randomized controlled trials (RCTs).
METHODS
We systematically searched four electronic databases including PubMed, Web of Science, Cochrane Library, and Embase for the eligible studies up to February 28, 2023. The Cochrane risk of bias tool was used for assessing the risk of bias in the included RCTs. The occurrence of POD was the primary outcome. The quality of evidence was evaluated by Grading of Recommendations Assessment, Development, and Evaluation.
RESULTS
A total of 11 RCTs comprising patients (MMRA group: 777 patients and placebo group: 781 patients) were included. The results of the meta-analysis showed that the MMRA group had a lower occurrence of POD than the placebo group (risk ratio = 0.70, 95% confidence interval: 0.51-0.97, P < 0.05, I = 59%). The subgroup analysis showed that melatonin significantly reduced the occurrence of POD (moderate-quality evidence), whereas ramelteon and tryptophan had no significant impact (moderate-quality evidence).
CONCLUSION
Existing evidence suggested that perioperative use of melatonin can prevent POD in elderly patients.
Topics: Humans; Aged; Emergence Delirium; Melatonin; Receptors, Melatonin; Randomized Controlled Trials as Topic; Hypnotics and Sedatives
PubMed: 37776484
DOI: 10.1007/s40520-023-02564-y -
Animals : An Open Access Journal From... Feb 2024Melatonin is a hormone mainly produced by the pineal gland in the absence of light stimuli. The light, in fact, hits the retina, which sends a signal to the... (Review)
Review
Melatonin is a hormone mainly produced by the pineal gland in the absence of light stimuli. The light, in fact, hits the retina, which sends a signal to the suprachiasmatic nucleus, which inhibits the synthesis of the hormone by the epiphysis. Mostly by interacting with MT1/MT2 membrane receptors, melatonin performs various physiological actions, among which are its regulation of the sleep-wake cycle and its control of the immune system. One of its best known functions is its non-enzymatic antioxidant action, which is independent from binding with receptors and occurs by electron donation. The hormone is also an indicator of the photoperiod in seasonally reproducing mammals, which are divided into long-day and short-day breeders according to the time of year in which they are sexually active and fertile. It is known that melatonin acts at the hypothalamic-pituitary-gonadal axis level in many species. In particular, it inhibits the hypothalamic release of GnRH, with a consequent alteration of FSH and LH levels. The present paper mainly aims to review the ovarian effect of melatonin.
PubMed: 38396612
DOI: 10.3390/ani14040644 -
American Family Physician Feb 2024Insomnia affects 30% of the U.S. population, with 5% to 15% meeting criteria for chronic insomnia. It can negatively impact quality of life, decrease productivity,...
Insomnia affects 30% of the U.S. population, with 5% to 15% meeting criteria for chronic insomnia. It can negatively impact quality of life, decrease productivity, increase fatigue and drowsiness, and put patients at higher risk of developing other health problems. Initial treatment focuses on nonpharmacologic therapies such as cognitive behavior therapy, which improves negative thought patterns and behaviors through sleep restriction, stimulus control, and relaxation techniques. Other nonpharmacologic treatments include exercise, mindfulness, and acupuncture. If these approaches are ineffective, pharmacologic agents may be considered. Medications such as benzodiazepines and Z-drugs are often prescribed for insomnia but should be avoided, if possible, due to short- and long-term risks associated with their use. Melatonin receptor agonists are safer and well tolerated but have limited effectiveness. Dual orexin receptor antagonists are effective in patients who have sleep maintenance insomnia or difficulty with sleep onset. Evidence for the use of antihistamines to treat insomnia is generally lacking, but doxylamine is effective for up to four weeks.
Topics: Adult; Humans; Sleep Initiation and Maintenance Disorders; Quality of Life; Benzodiazepines; Hypnotics and Sedatives; Sleep
PubMed: 38393799
DOI: No ID Found -
Biochimica Et Biophysica Acta.... Jan 2024Hypertrophic scar (HS) is a fibrotic skin condition and characterized by abnormal proliferation of myofibroblasts and accumulation of extracellular matrix. Melatonin, an...
Hypertrophic scar (HS) is a fibrotic skin condition and characterized by abnormal proliferation of myofibroblasts and accumulation of extracellular matrix. Melatonin, an endogenous hormone, can alleviate fibrosis in multiple models of diseases. This study examined the effect of melatonin on fibrosis in primary fibroblasts from human HS (HSFs) and a rabbit ear model and potential mechanisms. Melatonin treatment significantly decreased the migration and contraction capacity, collagen and α-smooth muscle actin (α-SMA) production in HSFs. RNA-sequencing and bioinformatic analyses indicated that melatonin modulated the expression of genes involved in autophagy and oxidative stress. Mechanistically, melatonin treatment attenuated the AKT/mTOR activation through affecting the binding of MT2 receptor with PI3K to enhance autophagy, decreasing fibrogenic factor production in HSFs. Moreover, melatonin treatment inhibited HS formation in rabbit ears by enhancing autophagy. The anti-fibrotic effects of melatonin were abrogated by treatment with an autophagy inhibitor (3-methyladenine, 3-MA), an Akt activator (SC79), or an MT2 selective antagonist (4-phenyl-2propionamidotetralin, 4-P-PDOT). Therefore, melatonin may be a potential drug for prevention and treatment of HS.
Topics: Animals; Humans; Rabbits; Autophagy; Cicatrix, Hypertrophic; Fibroblasts; Fibrosis; Melatonin; Phosphatidylinositol 3-Kinases; Proto-Oncogene Proteins c-akt; Receptor, Melatonin, MT2; TOR Serine-Threonine Kinases
PubMed: 37739092
DOI: 10.1016/j.bbadis.2023.166887 -
International Journal of Molecular... Oct 2023Bisphenols such as bisphenol A (BPA), S (BPS), C (BPC), F (BPF), AF (BPAF), tetrabromobisphenol, nonylphenol, and octylphenol are plasticizers used worldwide to... (Meta-Analysis)
Meta-Analysis Review
Bisphenols such as bisphenol A (BPA), S (BPS), C (BPC), F (BPF), AF (BPAF), tetrabromobisphenol, nonylphenol, and octylphenol are plasticizers used worldwide to manufacture daily-use articles. Exposure to these compounds is related to many pathologies of public health importance, such as infertility. Using a protector compound against the reproductive toxicological effects of bisphenols is of scientific interest. Melatonin and vitamins have been tested, but the results are not conclusive. To this end, this systematic review and meta-analysis compared the response of reproductive variables to melatonin and vitamin administration as protectors against damage caused by bisphenols. We search for controlled studies of male rats exposed to bisphenols to induce alterations in reproduction, with at least one intervention group receiving melatonin or vitamins (B, C, or E). Also, molecular docking simulations were performed between the androgen (AR) and estrogen receptors (ER), melatonin, and vitamins. About 1234 records were initially found; finally, 13 studies were qualified for review and meta-analysis. Melatonin plus bisphenol improves sperm concentration and viability of sperm and increases testosterone serum levels compared with control groups; however, groups receiving vitamins plus bisphenols had lower sperm concentration, total testis weight, and testosterone serum levels than the control. In the docking analysis, vitamin E had the highest negative MolDock score, representing the best binding affinity with AR and ER, compared with other vitamins and melatonin in the docking. Our findings suggest that vitamins could act as an endocrine disruptor, and melatonin is most effective in protecting against the toxic effects of bisphenols.
Topics: Male; Rats; Animals; Melatonin; Vitamins; Molecular Docking Simulation; Semen; Benzhydryl Compounds; Reproduction; Receptors, Estrogen; Vitamin A; Vitamin K; Testosterone; Endocrine Disruptors
PubMed: 37834378
DOI: 10.3390/ijms241914930 -
European Journal of Epidemiology Oct 2023Light-at-night triggers the decline of pineal gland melatonin biosynthesis and secretion and is an IARC-classified probable breast-cancer risk factor. We applied a...
Light-at-night triggers the decline of pineal gland melatonin biosynthesis and secretion and is an IARC-classified probable breast-cancer risk factor. We applied a large-scale molecular epidemiology approach to shed light on the putative role of melatonin in breast cancer. We investigated associations between breast-cancer risk and polymorphisms at genes of melatonin biosynthesis/signaling using a study population of 44,405 women from the Breast Cancer Association Consortium (22,992 cases, 21,413 population-based controls). Genotype data of 97 candidate single nucleotide polymorphisms (SNPs) at 18 defined gene regions were investigated for breast-cancer risk effects. We calculated adjusted odds ratios (ORs) and 95% confidence intervals (CI) by logistic regression for the main-effect analysis as well as stratified analyses by estrogen- and progesterone-receptor (ER, PR) status. SNP-SNP interactions were analyzed via a two-step procedure based on logic regression. The Bayesian false-discovery probability (BFDP) was used for all analyses to account for multiple testing. Noteworthy associations (BFDP < 0.8) included 10 linked SNPs in tryptophan hydroxylase 2 (TPH2) (e.g. rs1386492: OR = 1.07, 95% CI 1.02-1.12), and a SNP in the mitogen-activated protein kinase 8 (MAPK8) (rs10857561: OR = 1.11, 95% CI 1.04-1.18). The SNP-SNP interaction analysis revealed noteworthy interaction terms with TPH2- and MAPK-related SNPs (e.g. rs1386483 ∧ rs1473473 ∧ rs3729931: OR = 1.20, 95% CI 1.09-1.32). In line with the light-at-night hypothesis that links shift work with elevated breast-cancer risks our results point to SNPs in TPH2 and MAPK-genes that may impact the intricate network of circadian regulation.
Topics: Humans; Female; Breast Neoplasms; Melatonin; Bayes Theorem; Polymorphism, Single Nucleotide; Logistic Models; Case-Control Studies; Genetic Predisposition to Disease
PubMed: 37789226
DOI: 10.1007/s10654-023-01048-7 -
European Journal of Pharmacology Mar 2024Hepatic fibrosis, when left untreated, causes serious health problems that progress to cirrhosis and, in some cases, liver cancer. Activation of hepatic stellate cells...
Hepatic fibrosis, when left untreated, causes serious health problems that progress to cirrhosis and, in some cases, liver cancer. Activation of hepatic stellate cells may be a key characteristic in the development of hepatic fibrosis. Melatonin, a pineal hormone, exerts anti-fibrotic effects; however, the exact mechanisms remain unclear. In this study, the beneficial effects of melatonin against hepatic fibrosis and the underlying mechanisms were investigated using the human hepatic stellate cell line, LX-2, and in vivo murine animal models. The results showed that melatonin suppressed the expression of transforming growth factor (TGF)-β1-induced fibrosis markers and production of reactive oxygen species in LX-2 cells. Either 4-phenyl-2-propionamidotetralin, a melatonin receptor 2 selective antagonist, or melatonin receptor 2 small interfering RNA abolished the suppressive effects of melatonin, suggesting the involvement of melatonin receptor 2 in melatonin-induced anti-fibrotic and anti-oxidative actions. Melatonin increased the expression of the brain and muscle aryl hydrocarbon receptor nuclear translocator-like 1 (BMAL1), a positive circadian clock gene. BMAL1 knockdown reduced the anti-fibrotic and anti-oxidative effects of melatonin, demonstrating the protective effects of melatonin against TGF-β1-induced hepatic stellate cell activation by exhibiting melatonin receptor 2-BMAL1-anti-oxidative effects. In high-fat diet-induced and carbon tetrachloride-induced hepatic fibrosis models, oral melatonin administration decreased the expression of hepatic fibrosis markers and increased the expression of messenger RNA and levels of proteins of BMAL1 and melatonin receptor 2. Thus, melatonin exerted protective effects against hepatic fibrosis through melatonin receptor 2 activation, followed by an upregulation of the BMAL1-anti-oxidative enzyme pathways.
Topics: Animals; Humans; Mice; ARNTL Transcription Factors; Carbon Tetrachloride; Hepatic Stellate Cells; Liver; Liver Cirrhosis; Melatonin; Receptors, Melatonin; Signal Transduction; Transforming Growth Factor beta1; Up-Regulation
PubMed: 38246330
DOI: 10.1016/j.ejphar.2024.176337