Modulation by melatonin of the pathogenesis of inflammatory autoimmune diseases

Melatonin, an Antitumor Necrosis Factor Therapy

Tumor necrosis factor (TNF) is a biomarker of inflammation whose levels are elevated in patients with several diseases associated with dysregulation of the immune response. The main limitations of currently used anti-TNF therapies are the induction of immunodepression, which in many cases leads to serious adverse effects such as infection and cancer, and the inability to cross the blood-brain barrier in neuroinflammatory conditions. Melatonin, in addition to being a chronobiotic compound, is widely known for its antioxidant and immunomodulatory capacity to control inflammatory processes in different pathological contexts. The aim of the present review is to address human-based studies that describe the effect of melatonin on TNF production. The review includes all the articles published in PubMed databases until April 15, 2024. After depuration, 45 studies were finally included in the review, 23 related to the in vitro action of melatonin in human cells and 22 in vivo studies in humans. Most of the data reviewed support the idea that melatonin has an immunosuppressive effect on TNF levels, which, together with its low toxicity profile, low cost, and ability to cross the blood-brain barrier, points to melatonin as a potential anti-TNF therapy. Therefore, improving our knowledge of the action of melatonin in regulating TNF through appropriate clinical trials would reveal the true potential of this molecule as a possible anti-TNF therapy.

Evaluating the Protective Effects of Melatonin Against Chronic Iron Administration in Male Wistar Rats: a Comparative Analysis of Affective, Cognitive, and Oxidative Stress with EDTA Chelator

Iron is the dominant metal in the brain and is distributed widely. However, it can lead to various neuropathological and neurobehavioral abnormalities as well as oxidative stress. On the other hand, melatonin, a pineal hormone, is known for its neuroprotective properties, as well as its ability to act as a natural chelator against oxidative stress. It has also been used as an antidepressant and anxiolytic. The study investigated the potential of melatonin and EDTA treatment to prevent anxiety, depressive behavior, and memory impairment in male rats induced by chronic iron administration, and its connection to oxidative stress regulation in the hippocampus and prefrontal cortex. The rats were divided into six groups and intraperitoneally injected for 8 weeks with NaCl solution (control), iron sulfate (1 mg/kg), melatonin (4 mg/kg), EDTA (4 mg/kg), 1 mg/kg of iron + 4 mg/kg of melatonin, or 1 mg/kg of iron + 4 mg/kg of EDTA. In this study, we performed a neurobehavioral assessment and biochemical determinations of oxidative stress levels in the hippocampus and prefrontal cortex of each animal. The results indicate that chronic exposure to iron sulfate induced anxiety-like depressive behavior, and cognitive impairment also increased the levels of lipid peroxidation and nitric oxide, and reduced the activity of catalase in the hippocampus and prefrontal cortex in male Wistar rats, suggesting the induction of oxidative stress. In contrast, these alterations were reversed by melatonin better than EDTA. The results of this study show that melatonin protects against the neurobehavioral changes caused by iron, which may be associated with decreasing oxidative stress in the hippocampus and prefrontal cortex.

The Impact of Light-Dark Cycle Alteration on the Acceleration of Type 1 Diabetes in NOD Mice Model

Objective

We aimed to evaluate the effect of light-dark cycle alteration and soft drink consumption on the acceleration of type 1 diabetes mellitus (T1DM) development among non-obese diabetic (NOD) mice model.

Methods

We exposed female NOD and C57BL/6 mice from the age of 5 weeks to either adlib soft drink consumption and/or T20 light-dark cycle alteration until the development of diabetes, or the mice reached the age of 30 weeks. Each group consisted of 7-15 mice. We monitored weight, length, blood glucose level, and insulin autoantibody (IAA) levels weekly.

Results

Out of 75 NOD and 22 C57BL/6 mice, 41 NOD mice developed diabetes, and 6 mice died between 7 and 8 weeks of age. The mean time to development of T1DM among NOD control mice was 20 weeks. The time to development of T1DM was accelerated by two weeks in the NOD mice exposed to light-dark cycle alteration, hazard ratio of 2.65,95th CI (0.70, 10.04) p = 0.15). The other groups developed T1DM, similar to the control group.

Conclusion

There was a trend toward earlier development of T1DM among NOD mice exposed to light-dark cycle alteration, but this difference was not statistically significant. Further studies are needed to confirm our findings using larger sample sizes and different animal species.

Ameliorative effects of topical ramelteon on imiquimod-induced psoriasiform inflammation in mice

Psoriasis is a long-lasting, immune-related inflammatory skin disease that affects 2-3% of the global population. It is distinguished by erythematous, silvery, and scaly patches. Ramelteon is a type of melatonin agonist that is used to treat insomnia. It has enhanced non-classical immunomodulatory and anti-inflammatory activities. The aim of the study is to assess the ameliorative effects of topical ramelteon on imiquimod (IMQ)-aggravated psoriasiform-like dermatosis in mice. The 32 albino mouse males were placed into six groups of eight animals, all of them. With the exception of the control group, all groups gained a once-a-day regimen of topical imiquimod 5% cream at a dose of 62.5 mg for eight uninterrupted days, while mice in the control group gained vaseline-based ointment alternately. Immediately after an 8-day induction period in the imiquimod group, mice in the clobetasol and ramelteon treatment groups obtained a twice-daily regimen of topical clobetasol propionate 0.05% ointment and 0.1% ointment, respectively, for a further 8 days. This extends the total duration of the experimental study to 16 continuous days. The findings of our study found that ramelteon significantly mitigated the concentrations of inflammatory cytokines in the skin tissue, including interleukin (IL)-6, IL-17A, IL-23, tumor necrosis factor-α (TNF-α), and vascular endothelial growth factor (VEGF), as well as the scores associated with psoriatic lesions, including erythema, scaling, skin thickening, ear thickness, and overall cumulative PASI scores. Additionally, the anti-inflammatory impact of ramelteon was achieved by markedly increasing IL-10 levels in the skin tissue and correcting cutaneous histopathological alterations. Ramelteon ointment (0.1%) was comparable to that of clobetasol (0.05%) ointment in alleviating a mouse model of imiquimod-induced psoriasiform inflammation; this is probably due to its potential anti-inflammatory and immunomodulatory activities. Therefore, ramelteon could be a good additive option for therapeutic management of immune-triggered inflammatory conditions such as psoriasis.

Medications Used for Pediatric Insomnia

Pediatric insomnia can affect physical and mental health and cause cognitive deficits, social deficits and decrease quality of life. There are no Food and Drug Administration approved medications approved for pediatric insomnia. Pharmacologic interventions derive mostly from adult data or pediatric case reports. This review focuses on Food and Drug Administration approved prescription drugs (in adults), over-the-counter drugs, and off-label pediatric insomnia drugs. This review helps the clinician learn general principles, practice guidelines, and pharmacologic considerations for medication selection in the pediatric population. Pharmacologic management should be considered in combination with behavior therapy, which is proven to have long-lasting outcomes.

Melatonin as an immunomodulator in CD19-targeting CAR-T cell therapy: managing cytokine release syndrome

BACKGROUND

Chimeric antigen receptor CAR-T cell therapies have ushered in a new era of treatment for specific blood cancers, offering unparalleled efficacy in cases of treatment resistance or relapse. However, the emergence of cytokine release syndrome (CRS) as a side effect poses a challenge to the widespread application of CAR-T cell therapies. Melatonin, a natural hormone produced by the pineal gland known for its antioxidant and anti-inflammatory properties, has been explored for its potential immunomodulatory effects. Despite this, its specific role in mitigating CAR-T cell-induced CRS remains poorly understood.

METHODS

In this study, our aim was to investigate the potential of melatonin as an immunomodulatory agent in the context of CD19-targeting CAR-T cell therapy and its impact on associated side effects. Using a mouse model, we evaluated the effects of melatonin on CAR-T cell-induced CRS and overall survival. Additionally, we assessed whether melatonin administration had any detrimental effects on the antitumor efficacy and persistence of CD19 CAR-T cells.

RESULTS

Our findings demonstrate that melatonin effectively mitigated the severity of CAR-T cell-induced CRS in the mouse model, leading to improved overall survival outcomes. Remarkably, melatonin administration did not compromise the antitumor effectiveness or persistence of CD19 CAR-T cells, indicating its compatibility with therapeutic goals. These results suggest melatonin's potential as an immunomodulatory compound to alleviate CRS without compromising the therapeutic benefits of CAR-T cell therapy.

CONCLUSION

The study's outcomes shed light on melatonin's promise as a valuable addition to the existing treatment protocols for CAR-T cell therapies. By attenuating CAR-T cell-induced CRS while preserving the therapeutic impact of CAR-T cells, melatonin offers a potential strategy for optimizing and refining the safety and efficacy profile of CAR-T cell therapy. This research contributes to the evolving understanding of how to harness immunomodulatory agents to enhance the clinical application of innovative cancer treatments.

Disease-modifying therapies do not affect sleep quality or daytime sleepiness in a large Australian MS cohort

BACKGROUND

Poor sleep is common in multiple sclerosis (MS) and may impact daily functioning. The extent to which disease-modifying therapies (DMTs) contribute to sleep outcomes is under-examined.

OBJECTIVE

To compare the effects of DMTs on sleep outcomes in an Australian cohort of people with MS and investigate associations between DMT use and beliefs about sleep problems and daily functioning (social functioning and activity engagement).

METHODS

Sleep outcomes were assessed using the Pittsburgh Sleep Quality Index and the Epworth Sleepiness Scale. DMT use and functioning were self-reported.

RESULTS

Of 1,715 participants, 64% used a DMT. No differences in sleep outcomes were detected between participants who did and did not use DMTs, the type of DMT used (lower vs higher efficacy, interferon-β vs other DMTs), the timing of administration, or adherence to standard administration recommendations. Beliefs that DMT use worsened sleep were associated with poorer sleep quality and perceptions that sleep problems interfered with daily functioning.

CONCLUSION

The use of a DMT does not appear to affect self-reported sleep outcomes in people with MS. However, beliefs that DMT use makes sleep worse were associated with poorer sleep quality and increased interference in daily functioning, suggesting a need for education to diminish negative perceptions of DMT use.

Melatonin supplementation improves rheumatological disease activity: A systematic review

BACKGROUND

Melatonin is a pineal hormone with a complex role. It is linked to sleep, inflammatory, oxidative, and immunological processes.

AIM

To review the use of melatonin supplementation in rheumatological diseases.

METHODS

A systematic search of PubMed, Embase, and Scielo databases was performed, looking for articles on Melatonin and rheumatic diseases published between 1966 and August 2022.

RESULTS

Thirteen articles were identified: in fibromyalgia (n = 5 articles), rheumatoid arthritis (n = 2), systemic sclerosis (n = 1), systemic lupus erythematosus (n = 1) and osteoporosis/osteopenia (n = 3) and osteoarthritis (n = 1). There were positive results of melatonin administration in fibromyalgia, osteoarthritis, and osteoporosis/osteopenia but not in rheumatoid arthritis and lupus. The drug was well tolerated with mild side effects.

CONCLUSION

This review shows the efficacy of Melatonin in some rheumatic diseases. However, new studies are needed to elucidate the real role of this treatment in rheumatology.

Melatonin: a potential therapeutic approach for the management of primary Sjögren's syndrome

Primary Sjögren's syndrome (pSS) is an autoimmune disease that primarily affects the exocrine glands and is mainly characterized by sicca symptoms of the eyes and mouth. Approximately 30-50% of pSS patients develop systemic multi-organ disorders including malignant lymphoma. The etiology of pSS is not well understood; growing evidence suggests that uncontrolled immune/inflammatory responses, excessive oxidative stress, defected apoptosis, dysregulated autophagy, exosomes, and exogenous virus infections may participate in the pathogenesis of pSS. There is no ideal therapeutic method for pSS; the management of pSS is mainly palliative, which aims to alleviate sicca symptoms. Melatonin, as the main secretory product of the pineal gland, has been evidenced to show various physiological functions, including effects of immunoregulation, capability of antioxidation, moderation of autophagy, suppressive activities of apoptosis, regulative capacity of exosomes, properties of anti-infection, and improvement of sleep. The beneficial effects of melatonin have been already validated in some autoimmune diseases such as multiple sclerosis (MS), type 1 diabetes mellitus (T1DM), systemic lupus erythematosus (SLE), and inflammatory bowel disease (IBD). However, our previous research firstly revealed that melatonin might inhibit pathogenic responses of peripheral Th17 and double-negative (DN) T cells in pSS. More importantly, melatonin administration alleviated the development of pSS in animal models with reduced infiltrating lymphocytes, improved functional activity of salivary gland, and decreased production of inflammatory factors as well as autoantibodies. Owing to the important biological properties reported in melatonin are characteristics closely related to the treatment of pSS; the potential role and underlying mechanisms of melatonin in the administration of pSS are certainly worth further investigations. Consequently, the aim of this review is to give a deep insight to the therapeutic potency of melatonin for pSS.

Serotonin and Melatonin in Human Lower Gastrointestinal Tract

BACKGROUND AND AIMS

Melatonin is a ubiquitous hormone produced not only by the pineal gland but also by other organs and tissues. It is involved in the regulation of several gastrointestinal functions. The main cells responsible for the production and release of extrapineal melatonin are the enterochromaffin (EC) cells that produce serotonin. They are involved in the pathogenesis of neuromotor disorders that characterize functional gastrointestinal disorders and in the pathophysiology of inflammatory intestinal diseases. Our aim was the immunohistochemical highlighting on biopsy samples of normal gastrointestinal mucosa and in ulcerative colitis (UC) of immunoreactive cells for melatonin and serotonin in order to identify any differences in their distribution.

MATERIALS AND METHODS

Our prospective case-control study involves the highlighting on human mucosal biopsies of immunoreactive cells for melatonin and serotonin. All patients undergoing colonoscopy + ileoscopy were considered eligible for the study, divided into two groups: 1. patients with active ulcerative colitis (UC); 2. control group consisting of patients undergoing endoscopic examination for colorectal cancer screening.

RESULTS

Twenty-one patients were enrolled. The controls had a higher concentration of EC cells containing 5HT particularly in the rectum (p value ≤ 0.05). In patients with active colitis the expression of 5-HT-iR was greater in all tracts of the colon. The correlation analysis in UC patients shows that a higher expression of 5-HT-iR+ cells corresponds to a lower extension of the disease and a greater severity of the same.

CONCLUSIONS

5HT+ cells decreased in the case of UC compared to healthy controls. In the severe disease, there was an increase in the expression of melatonin-secreting cells, probably as a compensatory response to the inflammation and oxidative stress. This increase is negatively correlated with the extent of the disease and positively with the severity of the same.

Diet, sleep, and exercise in inflammatory skin diseases

Inflammatory skin conditions are significantly impacted by lifestyle habits, particularly those related to diet, exercise, and sleep. Although ancient cultures emphasized the importance of lifestyle behaviors as both etiology and therapy in disease, modern medicine often overlooks nonpharmacological therapy. However, recent studies show that diet can have a significant impact on inflammatory skin diseases such as psoriasis, hidradenitis suppurativa, and atopic dermatitis. Foods high in glycemic index, advanced glycation end-products, and omega-6 polyunsaturated fatty acids are associated with obesity and systemic inflammation, which can exacerbate inflammatory skin diseases. In addition, lifestyle behaviors such as exercise and sleep have been shown to have positive effects on inflammatory skin diseases. This review aims to highlight the importance of lifestyle behaviors in the context of inflammation and inflammatory dermatoses.

A pilot study on the melatonin treatment in patients with early septic shock: results of a single-center randomized controlled trial

BACKGROUND

We assessed the potential impact of a high dose of melatonin treatment in patients with early septic shock.

METHODS

Forty patients with early septic shock were randomly allocated to the melatonin or placebo groups. Besides standard-of-care treatment, melatonin and placebo were administered at a dose of 50 mg for five consecutive nights. The efficacy outcomes were severity of organ dysfunction based on the Sequential Organ Failure Assessment (SOFA) score, the number of patients requiring mechanical ventilation and ventilator-free days, the mean required vasopressor dose and vasopressor-free days, and 28 days all-cause mortality.

RESULTS

After 5-day treatment, the mean SOFA scores decreased 4.05 ± 4.75 score in the melatonin group and 2.25 ± 4.87 in the placebo group. On day 28, 60% of the melatonin-treated patients and 35% of the placebo-treated patients had a SOFA score below six. Thirteen cases in the placebo group and nine cases in the melatonin group required mechanical ventilation; however, there was no statistically significant difference between the groups regarding these outcomes. The melatonin-treated patients had more ventilator-free days than placebo-treated patients over the 28-day (16.90 ± 9.24 vs. 10.00 ± 10.94; p value = 0.035). The mean reduction in the required dose of vasopressor was 6.2 ± 5.12 in the melatonin-treated patients compared to 3.20 ± 3.95 in the placebo-treated patients (p value = 0.045). Vasopressor-free days in the melatonin-treated group were also significantly more than the placebo-treated group (12.75 ± 7.43 days vs. 10.15 ± 6.12 days; p value = 0.046).

CONCLUSIONS

Our pilot study supported the potential benefits of melatonin in treating septic shock. Further clinical evidence is required for expanding and confirming these findings.

TRIAL REGISTRATION

The trial was registered at Clinicaltrials.gov (ID code: IRCT20120215009014N296). Registration date: 15/09/2019.

Understanding the Concept of Pre-Clinical Autoimmunity: Prediction and Prevention of Systemic Lupus Erythematosus: Identifying Risk Factors and Developing Strategies Against Disease Development

There is growing evidence that preceding the diagnosis or classification of systemic lupus erythematosus (SLE), patients undergo a preclinical phase of disease where markers of inflammation and autoimmunity are already present. Not surprisingly then, even though SLE management has improved over the years, many patients will already have irreversible disease-related organ damage by time they have been diagnosed with SLE. By gaining a greater understanding of the pathogenesis of preclinical SLE, we can potentially identify patients earlier in the disease course who are at-risk of transitioning to full-blown SLE and implement preventative strategies. In this review, we discuss the current state of knowledge of SLE preclinical pathogenesis and propose a screening and preventative strategy that involves the use of promising biomarkers of early disease, modification of lifestyle and environmental risk factors, and initiation of preventative therapies, as examined in other autoimmune diseases such as rheumatoid arthritis and type 1 diabetes.

Circadian rhythm and disease: Relationship, new insights, and future perspectives

The circadian system is responsible for internal functions and regulation of the organism according to environmental cues (zeitgebers). Circadian rhythm dysregulation or chronodisruption has been associated with several diseases, from mental to autoimmune diseases, and with life quality change. Following this, some therapies have been developed to correct circadian misalignments, such as light therapy and chronobiotics. In this manuscript, we describe the circadian-related diseases so far investigated, and studies reporting relevant data on this topic, evidencing this relationship, are included. Despite the actual limitations in published work, there is clear evidence of the correlation between circadian rhythm dysregulation and disease origin/development, and, in this way, clock-related therapies emerge as great progress in the clinical field. Future improvements in such interventions can lead to the development of successful chronotherapy strategies, deeply contributing to enhanced therapeutic outcomes.

Melatonin and multiple sclerosis: antioxidant, anti-inflammatory and immunomodulator mechanism of action

BACKGROUND

Melatonin is an indole hormone secreted primarily by the pineal gland that showing anti-oxidant, anti-inflammatory and anti-apoptotic capacity. It can play an important role in the pathophysiological mechanisms of various diseases. In this regard, different studies have shown that there is a relationship between Melatonin and Multiple Sclerosis (MS). MS is a chronic immune-mediated disease of the Central Nervous System.

AIM

The objective of this review was to evaluate the mechanisms of action of melatonin on oxidative stress, inflammation and intestinal dysbiosis caused by MS, as well as its interaction with different hormones and factors that can influence the pathophysiology of the disease.

RESULTS

Melatonin causes a significant increase in the levels of catalase, superoxide dismutase, glutathione peroxidase, glutathione and can counteract and inhibit the effects of the NLRP3 inflammasome, which would also be beneficial during SARS-CoV-2 infection. In addition, melatonin increases antimicrobial peptides, especially Reg3β, which could be useful in controlling the microbiota.

CONCLUSION

Melatonin could exert a beneficial effect in people suffering from MS, running as a promising candidate for the treatment of this disease. However, more research in human is needed to help understand the possible interaction between melatonin and certain sex hormones, such as estrogens, to know the potential therapeutic efficacy in both men and women.

Effects of Modified Melatonin Release on Human Colostrum Neutrophils to Induce Death in the MCF-7 Cell Line

Cancer is one of the diseases with the highest mortality rate today, with breast cancer being the second most common type among the Brazilian population. Due to its etiological complexity and inefficiency of treatments, studies have focused on new forms of treatment. Among these forms of treatment, hormonal therapy seems to be an excellent auxiliary mechanism in tumoricidal activity, and melatonin has great potential as a modulator of the immune system. Thus, the present study is aimed at evaluating the effect of the hormone melatonin on the coculture of colostrum polymorphonuclear cells and MCF-7 cancer cells and evaluates the effect of this hormone using a modified transport system. A feasibility analysis was performed by fluorescence microscopy at three cell incubation times, 2 hours, 24 hours, and 72 hours. The measurement of cytokines in the cell supernatant occurred in 24 hours, and the apoptosis assay was performed in 72 hours using flow cytometry. The results showed higher levels of cell viability in groups treated with melatonin and less viability in groups containing a coculture of polymorphonuclear cells and MCF-7 after 72 hours of incubation. Furthermore, the apoptosis and necrosis rates were higher in coculture polymorphonuclear and MCF-7 cells, especially in groups containing microemulsion as a modified release agent. These data suggest that melatonin, especially if associated with a modified release system, has immunomodulatory effects on human colostrum polymorphonuclear cells. These cells can play a crucial role in the resolution of the tumor through their mediation and inflammatory action.

Melatonin alleviates the immune response and improves salivary gland function in primary Sjögren's syndrome

Primary Sjögren's syndrome (pSS) is an autoimmune disease that primarily affects exocrine glands and is characterized by sicca syndrome and systemic manifestation. Mounting evidence indicates that circadian clocks are involved in the onset and progression of autoimmune diseases, including rheumatic arthritis, multiple sclerosis, and systemic lupus erythematosus. However, few studies have reported the expression of clock genes in pSS. There is no ideal therapeuticmethod for pSS, the management of pSS is mainly palliative, aims to alleviate sicca symptoms. Melatonin is a neuroendocrine hormone mainly secreted by the pineal gland that plays an important role in the maintenance of the circadian rhythm and immunomodulation. Hence, this study aimed to analyse the circadian expression profile of clock genes in pSS, and further evaluate the therapeutic potential of melatonin in pSS. We discovered a distinct clock gene expression profile in an animal model and in patients with pSS. More importantly, melatonin administration regulated clock gene expression, improved the hypofunction of the salivary glands, and inhibited inflammatory development in animal model of pSS. Our study suggested that the pathogenesis of pSS might correlate with abnormal expression of circadian genes, and that melatonin might be a potential candidate for prevention and treatment of pSS.

Radiomitigation by Melatonin in C57BL/6 Mice: Possible Implications as Adjuvant in Radiotherapy and Chemotherapy

BACKGROUND/AIM

Melatonin (N-acetyl-5-methoxytryptamine), a chief secretory molecule of the pineal gland, has multiple properties, and numerous clinical investigations regarding its actions are in progress. This study investigated the radiomitigative role of melatonin in C57BL/6 mice.

MATERIALS AND METHODS

Melatonin (100 mg/kg) was orally administered once daily starting at 1 h on day 1 and subsequently every 24 h until day 7 after whole-body irradiation (WBI) and survival was monitored for 30 days. The bone marrow, spleen, and intestine were studied to evaluate the mitigative potential of melatonin after radiation-induced damage.

RESULTS

Melatonin significantly improved the survival upto 60% and 90% after 9 Gy (lethal) and 7.5 Gy (sub-lethal) WBI, respectively. Melatonin alleviated WBI-induced myelosuppression and pancytopenia, and increased white blood cell, red blood cell, platelet, and lymphocyte (CD4⁺ and CD8⁺) counts in peripheral blood. Bone marrow and spleen cellularity were restored through enhanced haematopoiesis. Melatonin ameliorated the damage in the small intestine, and promoted recovery of villi length, crypts number, and goblet cell count.

CONCLUSION

Melatonin mitigates the radiation-induced injury in the gastrointestinal and haematopoietic systems. The observed radiomitigative properties of melatonin can also be useful in the context of adjuvant therapy for cancer and radiotherapy.

Melatonin abolished proinflammatory factor expression and antagonized osteoarthritis progression in vivo

Progressive structural changes in osteoarthritis (OA) involve synovial inflammation and angiogenesis, as well as activation of the proinflammatory cytokines tumor necrosis factor alpha (TNF-α) and interleukin (IL)-8, and the angiogenic factor vascular endothelial growth factor (VEGF). The endogenous hormone melatonin (N-acetyl-5-methoxytryptamine) is involved in antioxidative and anti-inflammatory activities, but how it antagonizes OA progression via its specific receptors is unclear. Here, we demonstrate that the MT₁ melatonin receptor, but not the MT₂ receptor, is highly expressed in normal tissue and only minimally in OA tissue. By targeting the MT₁ receptor, melatonin reversed OA-induced pathology and effectively reduced levels of TNF-α, IL-8, and VEGF expression in OA synovial fibroblasts and synovium from rats with severe OA. Interestingly, we found that the anabolic activities of melatonin involved the MT₁ receptor, which upregulated microRNA-185a through the PI3K/Akt and ERK signaling pathways in OA synovial fibroblasts. Our investigation confirms the role of the MT₁ receptor in melatonin-induced anti-catabolic effects in OA disease.

Melatonin/Cyclodextrin Inclusion Complexes: A Review

Melatonin (MLT) is involved in many functions of the human body, mainly in sleeping-related disorders. It also has anti-oxidant potential and has been proven very effective in the treatment of seasonal affective disorders (SAD), which afflict some people during short winter days. Melatonin has been implicated in a range of other conditions, including Parkinson’s disease, Alzheimer’s and other neurological conditions, and in certain cancers. Its poor solubility in water leads to an insufficient absorption that led scientists to investigate MLT inclusion in cyclodextrins (CDs), as inclusion of drugs in CDs is a way of increasing the solubility of many lipophilic moieties with poor water solubility. The aim of this review is to gather all the key findings on MLT/CD complexes. The literature appraisal concluded that MLT inclusion leads to a 1:1 complex with the majority of CDs and increases the solubility of the hormone. The interactions of MLT with CDs can be studied by a variety of techniques, such as NMR, FT-IR, XRD and DCS. More importantly, the in vivo experiments showed an increase in the uptake of MLT when included in a CD.

Chronobiology and Chronotherapy in Inflammatory Joint Diseases

Circadian rhythm perturbations can impact the evolution of different conditions, including autoimmune diseases. This narrative review summarizes the current understanding of circadian biology in inflammatory joint diseases and discusses the potential application of chronotherapy. Proinflammatory cytokines are key players in the development and progression of rheumatoid arthritis (RA), regulating cell survival/apoptosis, differentiation, and proliferation. The production and secretion of inflammatory cytokines show a dependence on the human day–night cycle, resulting in changing cytokine plasma levels over 24 h. Moreover, beyond the circadian rhythm of cytokine secretion, disturbances in timekeeping mechanisms have been proposed in RA. Taking into consideration chronotherapy concepts, modified-release (MR) prednisone tablets have been introduced to counteract the negative effects of night-time peaks of proinflammatory cytokines. Low-dose MR prednisone seems to be able to improve the course of RA, reduce morning stiffness and morning serum levels of IL-6, and induce significant clinical benefits. Additionally, methotrexate (MTX) chronotherapy has been reported to be associated with a significant improvement in RA activity score. Similar effects have been described for polymyalgia rheumatica and gout, although the available literature is still limited. Growing knowledge of chronobiology applied to inflammatory joint diseases could stimulate the development of new drug strategies to treat patients in accordance with biological rhythms and minimize side effects.

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

Background:

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

Aims:

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

Methods:

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

Results:

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

Conclusion:

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

Melatonin reduces inflammation in intestinal cells, organoids and intestinal explants

Inflammatory bowel diseases (IBDs) are chronic and recurrent diseases that often occur in young people and place a heavy burden on public health in both developed and developing countries. Melatonin has been confirmed to be useful in various diseases, including Alzheimer's disease, liver injuries and diseases, and cancers, while its role in IBDs remains unclear. To uncover the function of melatonin in IBDs, three intestinal models, including Caco-2 cells, 3D intestinal organoids and intestinal explants, were used. It was found that different concentrations of melatonin could significantly inhibit the expression levels of NFκB and its downstream cytokines, including IL6 and IL8 in Caco-2 cells (*P < 0.05, **P < 0.01), 3D intestinal organoids (*P < 0.05, **P < 0.01) and intestinal explants (*P < 0.05, **P < 0.01). Melatonin abolished the activation of LPS on the expression levels of NFκB, IL6, and IL8 in three intestinal models (*P < 0.05, **P < 0.01, ***P < 0.001). Importantly, the roles of melatonin in the regulation of inflammation was dependent on its receptor (i.e., MTNR1), since it was found that silencing of the melatonin receptor (MTNR1A) abolished the reduction in inflammation induced by melatonin in Caco-2 cells (***P < 0.001) and 3D intestinal organoids (***P < 0.01, ****P < 0.0001). Herein, the findings in this study might provide useful information for understanding the pathogenesis of IBDs and developing novel drugs to treat the diseases.

Melatonin as a promising modulator of aging related neurodegenerative disorders: Role of microRNAs

One of the host risk factors involved in aging-related diseases is coupled with the reduction of endogenous melatonin (MLT) synthesis in the pineal gland. MLT is considered a well-known pleiotropic regulatory hormone to modulate a multitude of biological processes such as the regulation of circadian rhythm attended by potent anti-oxidant, anti-inflammatory, and anti-cancer properties. It has also been established that the microRNAs family, as non-coding mRNAs regulating post-transcriptional processes, also serve a crucial role to promote MLT-related advantageous effects in both experimental and clinical settings. Moreover, the anti-aging impact of MLT and miRNAs participation jointly are of particular interest, recently. In this review, we aimed to scrutinize recent advances concerning the therapeutic implications of MLT, particularly in the brain tissue in the face of aging. We also assessed the possible interplay between microRNAs and MLT, which could be considered a therapeutic strategy to slow down the aging process in the nervous system.

iTRAQ-based quantitative proteomics analysis of the hepatoprotective effect of melatonin on ANIT-induced cholestasis in rats

The therapeutic effects of melatonin on cholestatic liver injury have received widespread attention recently. The aim of the present study was to investigate the mechanisms of the anti-cholestatic effects of melatonin against α-naphthyl isothiocyanate (ANIT)-induced liver injury in rats and to screen for potential biomarkers of cholestasis through isobaric tags for relative and absolute quantitation (iTRAQ) proteomics. Rats orally received melatonin (100 mg/kg body weight) or an equivalent volume of 0.25% carboxymethyl cellulose sodium salt 12 h after intraperitoneal injection of ANIT (75 mg/kg) and were subsequently sacrificed at 36 h after injection. Liver biochemical indices were determined and liver tissue samples were stained using hematoxylin-eosin staining, followed by iTRAQ quantitative proteomics to identify potential underlying therapeutic mechanisms and biomarkers. The results suggested that the expression levels of alanine transaminase, aspartate aminotransferase, total bilirubin and direct bilirubin were reduced in the rats treated with melatonin. Histopathological observation indicated that melatonin was effective in the treatment of ANIT-induced cholestasis. iTRAQ proteomics results suggested that melatonin-mediated reduction in ANIT-induced cholestasis may be associated with enhanced antioxidant function and relieving abnormal fatty acid metabolism. According to pathway enrichment analysis using the Kyoto Encyclopedia of Genes and Genomes, the major metabolic pathways for the metabolism of melatonin are fatty acid degradation, the peroxisome proliferator-activated receptor signaling pathway, fatty acid metabolism, chemical carcinogenesis, carbon metabolism, pyruvate metabolism, fatty acid biosynthesis and retinol metabolism, as well as drug metabolism via cytochrome P450. Malate dehydrogenase 1 and glutathione S-transferase Yb-3 may serve as potential targets in the treatment of ANIT-induced cholestasis with melatonin.

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.

A comparative study of melatonin and immunomodulatory therapy with interferon beta and glatiramer acetate in a mouse model of multiple sclerosis

INTRODUCTION

Multiple sclerosis (MS) is a chronic, demyelinating, autoimmune disease of the central nervous system causing neuroinflammation. Experimental autoimmune encephalitis (EAE) is a model of the disease. MS is classically treated with interferon beta (IFN-β) and glatiramer acetate (GA). Melatonin (MLT) has been reported to modulate immune system responses. The aim of the present study is to analyse the effects of MLT administration in comparison with the first-line treatments for MS (IFN-β and GA).

METHODS

EAE was induced in male Sprague-Dawley rats; the animals subsequently received either IFN-β, GA, or MLT. Cerebrospinal fluid (CSF) samples were analysed by multiplex assay to determine the levels of proinflammatory cytokines. The neurological evaluation of EAE was also recorded.

RESULTS

All immunised animals developed EAE. We evaluated the first relapse-remission cycle, observing that IFN-β and GA had better results than MLT in the clinical evaluation. Neither EAE nor any of the treatments administered modified CSF IL-1β and IL-12p70 concentrations. However, IFN-β and MLT did decrease CSF TNF-α concentrations.

CONCLUSIONS

Further studies are needed to evaluate the molecular mechanisms involved in the behaviour of MLT in EAE, and to quantify other cytokines in different biological media in order for MLT to be considered an anti-inflammatory agent capable of regulating MS.

Transcription Factor Activity Inference in Systemic Lupus Erythematosus

Background: Systemic Lupus Erythematosus (SLE) is a systemic autoimmune disease with diverse clinical manifestations. Although most of the SLE-associated loci are located in regulatory regions, there is a lack of global information about transcription factor (TFs) activities, the mode of regulation of the TFs, or the cell or sample-specific regulatory circuits. The aim of this work is to decipher TFs implicated in SLE. Methods: In order to decipher regulatory mechanisms in SLE, we have inferred TF activities from transcriptomic data for almost all human TFs, defined clusters of SLE patients based on the estimated TF activities and analyzed the differential activity patterns among SLE and healthy samples in two different cohorts. The Transcription Factor activity matrix was used to stratify SLE patients and define sets of TFs with statistically significant differential activity among the disease and control samples. Results: TF activities were able to identify two main subgroups of patients characterized by distinct neutrophil-to-lymphocyte ratio (NLR), with consistent patterns in two independent datasets—one from pediatric patients and other from adults. Furthermore, after contrasting all subgroups of patients and controls, we obtained a significant and robust list of 14 TFs implicated in the dysregulation of SLE by different mechanisms and pathways. Among them, well-known regulators of SLE, such as STAT or IRF, were found, but others suggest new pathways that might have important roles in SLE. Conclusions: These results provide a foundation to comprehend the regulatory mechanism underlying SLE and the established regulatory factors behind SLE heterogeneity that could be potential therapeutic targets.

Microbiota-Derived Metabolites, Indole-3-aldehyde and Indole-3-acetic Acid, Differentially Modulate Innate Cytokines and Stromal Remodeling Processes Associated with Autoimmune Arthritis

Rheumatoid arthritis (RA) is an autoimmune disease characterized by chronic inflammation of the synovial joints. Inflammation, new blood vessel formation (angiogenesis) and bone resorption (osteoclastogenesis) are three key processes involved in the joint damage and deformities of arthritis. Various gut microbiota-derived metabolites are implicated in RA pathogenesis. However, there is barely any information about the impact of two such metabolites, indole-3-aldehyde (IAld) and indole-3-acetic acid (I3AA), on arthritis-related processes. We conducted a comparative analysis of IAld and I3AA using established cell-based models to understand how they might influence RA pathogenesis. Although structurally similar, the bioactivities of these two metabolites were profoundly different. IAld but not I3AA, inhibited the expression of pro-inflammatory cytokines (IL-1β and IL-6) in RAW 264.7 (RAW) cells stimulated with heat-killed M. tuberculosis sonicate (Mtb) and lipopolysaccharide (LPS). IAld also exhibited pro-angiogenic activity and pro-osteoclastogenic activity. In contrast, I3AA exhibited anti-angiogenic activity on endothelial cell tube formation but had no effect on osteoclastogenesis. Both IAld and I3AA have been proposed as aryl hydrocarbon receptor (AhR) agonists. Use of CH-223191, an inhibitor of the AhR, suppressed the anti-angiogenic activity of I3AA but failed to mitigate the effects of IAld. Further investigation of the anti-inflammatory activities of IAld and I3AA in LPS-treated RAW cells indicated that inhibition of MyD88-dependent activation of NF-κB and MAPK pathways was not likely involved. Our results suggest that the relative bioavailability of these indole derivatives may differentially impact RA progression and possibly other diseases that share similar cellular processes.

Perspective Adjunctive Therapies for COVID-19: Beyond Antiviral Therapy

The coronavirus disease 2019 (COVID-19) pandemic is the largest health crisis ever faced worldwide. It has resulted in great health and economic costs because no effective treatment is currently available. Since infected persons vary in presentation from healthy asymptomatic mild symptoms to those who need intensive care support and eventually succumb to the disease, this illness is considered to depend primarily on individual immunity. Demographic distribution and disease severity in several regions of the world vary; therefore, it is believed that natural inherent immunity provided through dietary sources and traditional medicines could play an important role in infection prevention and disease progression. People can boost their immunity to prevent them from infection after COVID-19 exposure and can reduce their inflammatory reactions to protect their organ deterioration in case suffering from the disease. Some drugs with in-situ immunomodulatory and anti-inflammatory activity are also identified as adjunctive therapy in the COVID-19 era. This review discusses the importance of COVID-19 interactions with immune cells and inflammatory cells; and further emphasizes the possible pathways related with traditional herbs, medications and nutritional products. We believe that such pathophysiological pathway approach treatment is rational and important for future development of new therapeutic agents for prevention or cure of COVID-19 infection.

Medications Used for Pediatric Insomnia

Pediatric insomnia can affect physical and mental health and cause cognitive deficits, social deficits and decrease quality of life. There are no Food and Drug Administration approved medications approved for pediatric insomnia. Pharmacologic interventions derive mostly from adult data or pediatric case reports. This review focuses on Food and Drug Administration approved prescription drugs (in adults), over-the-counter drugs, and off-label pediatric insomnia drugs. This review helps the clinician learn general principles, practice guidelines, and pharmacologic considerations for medication selection in the pediatric population. Pharmacologic management should be considered in combination with behavior therapy, which is proven to have long-lasting outcomes.

Amino Acid Metabolism in Rheumatoid Arthritis: Friend or Foe?

In mammals, amino acid metabolism has evolved to act as a critical regulator of innate and adaptive immune responses. Rheumatoid arthritis (RA) is the most common form of inflammatory arthropathy sustained by autoimmune responses. We examine here the current knowledge of tryptophan and arginine metabolisms and the main immunoregulatory pathways in amino acid catabolism, in both RA patients and experimental models of arthritis. We found that l-tryptophan (Trp) metabolism and, in particular, the kynurenine pathway would exert protective effects in all experimental models and in some, but not all, RA patients, possibly due to single nucleotide polymorphisms in the gene coding for indoleamine 2,3-dioxygenase 1 (IDO1; the enzyme catalyzing the rate-limiting step of the kynurenine pathway). The function, i.e., either protective or pathogenetic, of the l-arginine (Arg) metabolism in RA was less clear. In fact, although immunoregulatory arginase 1 (ARG1) was highly induced at the synovial level in RA patients, its true functional role is still unknown, possibly because of few available preclinical data. Therefore, our analysis would indicate that amino acid metabolism represents a fruitful area of research for new drug targets for a more effective and safe therapy of RA and that further studies are demanding to pursue such an important objective.

Risperidone attenuates acetic acid-induced colitis in rats through inhibition of TLR4/NF-kB signaling pathway

AIM

The purpose of the present study is to explore the anti-inflammatory potential of risperidone in acetic acid-induced rat colitis through inhibition of TLR4/NF-kB pathway.

METHODS

Acute colitis induction was done by intra-rectal administration of 2 mL of 4% diluted acetic acid solution. Two h after colitis induction, dexamethasone (2 mg/kg) as standard drugorrisperidone (2, 4 and 6 mg/kg) were administered orally to wistar rats for five consecutive days. 24 h after the last treatment, animals were sacrificed by cervical dislocation. Macroscopic and microscopic damage evaluation was done. Biochemical and ELISA methods were used to assess myeloid peroxidase (MPO) enzyme activity and tumor necrosis factor-α (TNF-α) level respectively. Moreover, immunohistochemistry (IHC) was performed to detect the expression of TLR4 and pNF-kBproteins.

RESULTS

Dexamethasone (2 mg/kg) or risperidone (2, 4 and 6 mg/kg) improved acetic acid-induced macroscopic (p < .001) and microscopic lesions. Additionally, risperidone (2, 4 and 6 mg/kg) inhibited the activity of MPO and TNF-α (p < .01, p < .001) in the colon tissue compared to acetic acid group. Furthermore, bothdexamethasone and risperidone (2, 4 and 6 mg/kg) significantly reduced acetic acid-induced expression of TLR4and pNF-kB proteins (p < .05, p < .01, p < .001).

CONCLUSION

The anti-inflammatory effect of risperidone on acetic acid-induced colitis in rats may involve inhibition of TLR4 and NF-kB signaling pathway.

Reconsidering the Role of Melatonin in Rheumatoid Arthritis

Rheumatoid arthritis (RA) is an inflammatory joint disorder characterized by synovial proliferation and inflammation, with eventual joint destruction if inadequately treated. Modern therapies approved for RA target the proinflammatory cytokines or Janus kinases that mediate the initiation and progression of the disease. However, these agents fail to benefit all patients with RA, and many lose therapeutic responsiveness over time. More effective or adjuvant treatments are needed. Melatonin has shown beneficial activity in several animal models and clinical trials of inflammatory autoimmune diseases, but the role of melatonin is controversial in RA. Some research suggests that melatonin enhances proinflammatory activities and thus promotes disease activity in RA, while other work has documented substantial anti-inflammatory and immunoregulatory properties of melatonin in preclinical models of arthritis. In addition, disturbance of the circadian rhythm is associated with RA development and melatonin has been found to affect clock gene expression in joints of RA. This review summarizes current understanding about the immunopathogenic characteristics of melatonin in RA disease. Comprehensive consideration is required by clinical rheumatologists to balance the contradictory effects.

Identification of common key genes and pathways between type 1 diabetes and multiple sclerosis using transcriptome and interactome analysis

PURPOSE

Type 1 diabetes (T1D) and multiple sclerosis (MS) are classified as T cell-mediated autoimmune diseases. Although convergent evidence proposed common genetic architecture for autoimmune diseases, it remains a challenge to identify them. This study aimed to determine common gene signature and pathways in T1D and MS via systems biology approach.

METHODS

Gene expression profiles of peripheral blood mononuclear cells (PBMCs) and pancreatic-β cells in T1D as well as PBMCs and cerebrospinal fluid (CSF) in MS were analyzed in our previous published data, and differential expressed genes were integrated with protein-protein interactions data to construct Query-Query PPI (QQPPI) networks. In this study, QQPPI networks were further analyzed to investigate more central genes, functional modules and complexes shared in T1D and MS progression. Lastly, the interaction of common genes with drugs was also explored.

RESULTS

Several cytokines such as IL-23A, IL-32, IL-34, and IL-37 tend to be differentially expressed in both diseases. In addition, PSMA1, MYC, SRPK1, YBX1, HNRNPM, NF-κB2, IKBKE, RAC1, FN1, ARRB2, ESR1, HSP90AB1, and PPP1CA were common high central genes in QQPPI networks corresponding to each disease. Proteasome, spliceosome, immune responses, apoptosis, cellular communication/signaling transduction mechanism, interaction with environment, and activity of intercellular mediators were shared biological processes in T1D and MS. Finally, azathioprine, melatonin, resveratrol, and geldanamycin identified as prioritized drugs for the treatment of patients with T1D and MS.

CONCLUSIONS

This study represented novel key genes and pathways shared between T1D and MS, which may facilitate the identification of potential therapeutic targets in these diseases.

Longitudinal Metabolome-Wide Signals Prior to the Appearance of a First Islet Autoantibody in Children Participating in the TEDDY Study

Children at increased genetic risk for type 1 diabetes (T1D) after environmental exposures may develop pancreatic islet autoantibodies (IA) at a very young age. Metabolic profile changes over time may imply responses to exposures and signal development of the first IA. Our present research in The Environmental Determinants of Diabetes in the Young (TEDDY) study aimed to identify metabolome-wide signals preceding the first IA against GAD (GADA-first) or against insulin (IAA-first). We profiled metabolomes by mass spectrometry from children's plasma at 3-month intervals after birth until appearance of the first IA. A trajectory analysis discovered each first IA preceded by reduced amino acid proline and branched-chain amino acids (BCAAs), respectively. With independent time point analysis following birth, we discovered dehydroascorbic acid (DHAA) contributing to the risk of each first IA, and γ-aminobutyric acid (GABAs) associated with the first autoantibody against insulin (IAA-first). Methionine and alanine, compounds produced in BCAA metabolism and fatty acids, also preceded IA at different time points. Unsaturated triglycerides and phosphatidylethanolamines decreased in abundance before appearance of either autoantibody. Our findings suggest that IAA-first and GADA-first are heralded by different patterns of DHAA, GABA, multiple amino acids, and fatty acids, which may be important to primary prevention of T1D.

The role of melatonin in Multiple Sclerosis

Melatonin is a neurohormone mainly produced by the pineal gland following a circadian rhythm. It is characterized as a pleiotropic factor because it not only regulates the wake-sleep rhythm but also exerts antinociceptive, antidepressant, anxiolytic, and immunomodulating properties. Recent studies suggest that dysregulation of melatonin secretion is associated with the pathogenesis of various autoimmune diseases, such as, rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), and multiple sclerosis (MS). MS is an autoimmune disorder characterized by an abnormal immune response directed against the myelin sheath in the central nervous system, demyelination, oligodendrocyte death, and axonal degeneration. Recent evidence reveals that melatonin secretion is dysregulated in MS patients, suggesting that melatonin could be a potential target for therapeutic intervention. Here, we summarize the available literature regarding the role of melatonin in immune processes relevant for experimental autoimmune encephalomyelitis (EAE), MS, and the current clinical trials of melatonin supplementation in MS patients.

Adverse Events Associated with Melatonin for the Treatment of Primary or Secondary Sleep Disorders: A Systematic Review

BACKGROUND

Melatonin is widely available either on prescription for the treatment of sleep disorders or as an over-the-counter dietary supplement. Melatonin has also recently been licensed in the UK for the short-term treatment of jetlag. Little is known about the potential for adverse events (AEs), in particular AEs resulting from long-term use. Concern has been raised over the possible risks of exposure in certain populations including pre-adolescent children and patients with epilepsy or asthma.

OBJECTIVES

The aim of this systematic review was to assess the evidence for AEs associated with short-term and longer-term melatonin treatment for sleep disorders.

METHODS

A literature search of the PubMed/Medline database and Google Scholar was conducted to identify randomised, placebo-controlled trials (RCTs) of exogenous melatonin administered for primary or secondary sleep disorders. Studies were included if they reported on both the types and frequencies of AEs. Studies of pre-term infants, studies of < 1 week in duration or involving single doses of melatonin and studies in languages other than English were excluded. Findings from open-label studies that raised concerns relating to AE reports in patients were also examined. Studies were assessed for quality of reporting against the Consolidated Standards of Reporting Trials (CONSORT) checklist and for risk of bias against the Cochrane Collaboration risk-of-bias criteria.

RESULTS

37 RCTs met criteria for inclusion. Daily melatonin doses ranged from 0.15 mg to 12 mg. Subjects were monitored for up to 29 weeks, but most studies were of much shorter duration (4 weeks or less). The most frequently reported AEs were daytime sleepiness (1.66%), headache (0.74%), other sleep-related AEs (0.74%), dizziness (0.74%) and hypothermia (0.62%). Very few AEs considered to be serious or of clinical significance were reported. These included agitation, fatigue, mood swings, nightmares, skin irritation and palpitations. Most AEs either resolved spontaneously within a few days with no adjustment in melatonin, or immediately upon withdrawal of treatment. Melatonin was generally regarded as safe and well tolerated. Many studies predated publication of the CONSORT checklist and consequently did not conform closely to the guidelines. Similarly, only eight studies were judged 'good' overall with respect to the Cochrane risk-of-bias criteria. Of the remaining papers, 16 were considered 'fair' and 13 'poor' but publication of almost half of the papers preceded that of the earliest version of the guidelines.

CONCLUSION

Few, generally mild to moderate, AEs were associated with exogenous melatonin. No AEs that were life threatening or of major clinical significance were identified. The scarcity of evidence from long-term RCTs, however, limits the conclusions regarding the safety of continuous melatonin therapy over extended periods. There are insufficient robust data to allow a meaningful appraisal of concerns that melatonin may result in more clinically significant adverse effects in potentially at-risk populations. Future studies should be designed to comply with appropriate quality standards for RCTs, which most past studies have not.

Perinatal Use of Melatonin for Offspring Health: Focus on Cardiovascular and Neurological Diseases

Cardiovascular and neurological diseases can originate in early life. Melatonin, a biologically active substance, acts as a pleiotropic hormone essential for pregnancy and fetal development. Maternal melatonin can easily pass the placenta and provide photoperiodic signals to the fetus. Though melatonin uses in pregnant or lactating women have not yet been recommended, there is a growing body of evidence from animal studies in support of melatonin as a reprogramming strategy to prevent the developmental programming of cardiovascular and neurological diseases. Here, we review several key themes in melatonin use in pregnancy and lactation within offspring health and disease. We have particularly focused on the following areas: the pathophysiological roles of melatonin in pregnancy, lactation, and fetal development; clinical uses of melatonin in fetal and neonatal diseases; experimental evidence supporting melatonin as a reprogramming therapy to prevent cardiovascular and neurological diseases; and reprogramming mechanisms of melatonin within developmental programming. The targeting of melatonin uses in pregnancy and lactation will be valuable in the prevention of various adult chronic diseases in later life, and especially cardiovascular and neurological diseases.

Fatigue, Sleep, and Autoimmune and Related Disorders

Profound and debilitating fatigue is the most common complaint reported among individuals with autoimmune disease, such as systemic lupus erythematosus, multiple sclerosis, type 1 diabetes, celiac disease, chronic fatigue syndrome, and rheumatoid arthritis. Fatigue is multi-faceted and broadly defined, which makes understanding the cause of its manifestations especially difficult in conditions with diverse pathology including autoimmune diseases. In general, fatigue is defined by debilitating periods of exhaustion that interfere with normal activities. The severity and duration of fatigue episodes vary, but fatigue can cause difficulty for even simple tasks like climbing stairs or crossing the room. The exact mechanisms of fatigue are not well-understood, perhaps due to its broad definition. Nevertheless, physiological processes known to play a role in fatigue include oxygen/nutrient supply, metabolism, mood, motivation, and sleepiness-all which are affected by inflammation. Additionally, an important contributing element to fatigue is the central nervous system-a region impacted either directly or indirectly in numerous autoimmune and related disorders. This review describes how inflammation and the central nervous system contribute to fatigue and suggests potential mechanisms involved in fatigue that are likely exhibited in autoimmune and related diseases.

Gene and Mirna Regulatory Networks During Different Stages of Crohn's Disease

BACKGROUND AND AIMS

Early treatment of Crohn's disease [CD] is required in order to optimize patient outcomes. To this end, we need to gain a better understanding of the molecular changes at the onset of CD.

METHODS

As a model for the earliest mucosal CD lesions, we study post-operative recurrent CD [Rutgeerts score ≥ i2b]. We are the first to analyse gene and microRNA [miRNA] expression profiles in ileal biopsies from these patients, and compare them with those of newly diagnosed [≤18 months] and late-stage [>10 years after diagnosis] CD patients.

RESULTS

Except for one gene [WNT5A], there are no differential genes in CD patients without post-operative recurrence [i0], showing that previous disease did not influence gene expression in the neoterminal ileum, and that this model can be used to study early mucosal CD lesions. Gene expression and co-expression network dysregulation is more pronounced in newly diagnosed and late-stage CD than in post-operative recurrent CD, with most important modules associated with [a]granulocyte adhesion/diapedesis, and cholesterol biosynthesis. In contrast, we found a role for snoRNAs/miRNAs in recurrent CD, highlighting the potential importance of regulatory RNAs in early disease stages. Immunohistochemistry confirmed the expression of key dysregulated genes in damaged/regenerating epithelium and immune cells in recurrent CD.

CONCLUSIONS

Aside from regulatory RNAs, there are no clear gene signatures separating post-operative recurrent, newly diagnosed, and late-stage CD. The relative contribution of dysregulated genes and networks differs, and suggests that surgery may reset the disease at the mucosal site, and therefore post-operative recurrent CD might be a good model a good model to study to study early mucosal CD lesions.

High melatonin levels are related to spinal ossification in patients with ankylosing spondylitis

Objectives: To investigate associations of serum melatonin with spinal ossification and cytokines in ankylosing spondylitis (AS).Methods: Serum was obtained from 52 AS patients and 25 healthy controls. Melatonin was measured by ELISA kit; bone morphogenetic protein (BMP)-2, dickkopf-related protein (Dkk)-1, IL-1β, IL-6, IL-17 and TNF-α concentrations were assayed using Luminex multiplex bead system. Osteocalcin and β isomer of C-terminal telopeptide of type I collagen (β-CTX) were measured using electrochemiluminescence immunoassay. Spinal damages were assessed using the modified Stoke Ankylosing Spondylitis Spinal Score (mSASSS) on radiographs.Results: Serum melatonin was significantly increased in AS patients. Serum melatonin correlated positively with mSASSS after multivariate adjustment for age and disease duration (r = 0.70, p < .01). Patients with spinal bone bridge have higher levels of melatonin than those without spinal bone bridge [16.69 (4.65, 41.10) pg/ml vs. 7.43 (3.29, 15.30) pg/ml, p = .03]. The multiple linear regression analysis found that melatonin was a risk factor for spinal bone formation (β = 0.35, p < .05). Additionally, melatonin correlated positively with osteocalcin (r = 0.34, p = .04) and IL-1β (r = 0.39, p = .04) in AS.Conclusion: Melatonin is increased in AS patients, especially in patients with spinal bone bridge. It suggests that melatonin may play an important role in the pathological osteogenesis of AS.

Measurement of melatonin, indole-dioxygenase, IL-6, IL-18, ferritin, CRP, and total homocysteine levels during herpes zoster

The risk of herpes zoster (HZ) increases with age and declining immune function. Increased oxidative stress and inflammatory conditions may cause a negative impact on the immune responses. The present study aimed to assess the levels of oxidative/inflammatory stress biomarkers in HZ patients compared with the controls. This case-control study included 43 HZ patients and 47 age-matched controls. Melatonin (MLT), Indole-dioxygenase (IDO), Interleukin-18 (IL-18), Interleukin-6 (IL-6), ferritin, C-reactive protein (hsCRP), and total homocysteine (tHcy) levels were measured and compared in both groups. The significant high levels of IDO, IL-18, IL-6, ferritin, hsCRP, and tHcy, as well as low levels of MLT were found in HZ patients compared with the controls (P < 0.001); these significant differences were also associated with rash and pain severity (P < 0.001). The final logistic regression model with the area under the curve (0.99; 95% confidence interval [CI], 0.98-1.00) showed the association of HZ with decreased level of MLT (odds ratio [OR], 0.95; 95% CI, 0.92-0.98; P = 0.007) and increased levels of tHcy (OR, 1.53; 95% CI, 1.06-2.19; P = 0.02). The findings showed increased inflammation-associated oxidative stress in HZ patients. Elevated tHcy levels and reduced MLT levels may be associated with the manifestation of HZ. More investigations are required to confirm the results.

Effects of exogenous melatonin on clinical and pathological features of a human thyroglobulin-induced experimental autoimmune thyroiditis mouse model

Melatonin (MLT) plays a significant role in both innate and adaptive immunity, and dysregulation of the MLT signature can modify autoimmune disease phenotypes. In this study, the influence of exogenous MLT administration on regulating autoimmune thyroiditis animal models was evaluated. An experimental autoimmune thyroiditis model was established in MLT-synthesizing (CBA) and MLT-deficient (C57BL/6) mice by immunization with human thyroidglobulin (TG), which features thyrotoxicosis, thyrocyte damage, and CD3⁺ T cell infiltration. In TG-immunized CBA mice, exogenous MLT administration in drinking water (6 μg/ml) enhanced thyroiditis and increased TG-specific splenocyte proliferation but not the anti-thyroglobulin antibody (ATA) titer, while MLT alone caused no significant alteration in thyroid function or histopathology. Meanwhile, MLT administration did not modify thyroid function, the ATA titer, or the thyroid histopathology, but results showed an increase in the splenocyte proliferative capacity in TG-immunized C57BL/6 mice. Collectively, our data showed that early exogenous MLT modified the progression of autoimmune thyroiditis through T cell-driven immunity, and excess MLT worsened the clinical and pathological features.

Melatonin attenuates TNF-α and IL-1β expression in synovial fibroblasts and diminishes cartilage degradation: Implications for the treatment of rheumatoid arthritis

The hormone melatonin has many properties, including antioxidant, anti-inflammatory, and immunomodulatory effects. Melatonin has been demonstrated to be beneficial in several inflammatory autoimmune diseases, but its effects in rheumatoid arthritis (RA) remain controversial. We sought to determine how melatonin regulates inflammation in RA. We found that melatonin dose-dependently inhibits tumor necrosis factor-α (TNF-α) and interleukin (IL)-1β expression through the PI3K/AKT, ERK, and NF-κB signaling pathways. We also identified that melatonin inhibits TNF-α and IL-1β production by upregulating miR-3150a-3p expression. Synovial tissue specimens from RA patients and culture of human rheumatoid fibroblast-like synoviocytes confirmed that the MT1 receptor is needed for the anti-inflammatory activities of melatonin. Importantly, melatonin also significantly reduced paw swelling, cartilage degradation, and bone erosion in the collagen-induced arthritis mouse model. Our results indicate that melatonin ameliorates RA by inhibiting TNF-α and IL-1β production through downregulation of the PI3K/AKT, ERK, NF-κB signaling pathways, as well as miR-3150a-3p overexpression. The role of melatonin as an adjuvant treatment in patients with RA deserves further clinical studies.

Efficacy of Melatonin on Serum Pro-inflammatory Cytokines and Oxidative Stress Markers in Relapsing Remitting Multiple Sclerosis

Multiple sclerosis (MS) is a chronic inflammatory disease, which leads to focal plaques of demyelination and tissue injury in the central nervous system (CNS). Neuroinflammation and oxidative stress are involved in the pathogenesis of MS, promoting tissue damage and demielinization. Current research findings suggest that melatonin has antioxidant and neuroprotective effects. The aim of this study was to evaluate the efficacy of melatonin on serum pro-inflammatory cytokines and oxidative stress markers in relapsing-remitting multiple sclerosis (RRMS). 36 patients diagnose with RRMS treated with Interferon β-1b (IFNβ-1b) were enrolled in a double bind, randomized, placebo controlled trial. The experimental group received orally 25 mg/d of melatonin for 6 months. After melatonin administration, we observed a significant decrease in serum concentration of pro-inflammatory cytokines and oxidative stress markers; 18% for TNF-α (p <0.05), 34.8% for IL-1β (p <0.05), 34.7% for IL-6 (p <0.05), 39.9% for lipoperoxides (LPO) (p <0.05) and 24% for nitric oxide catabolites (NOC) levels (p <0.05), compared with placebo group. No significant difference in clinical efficacy outcomes were found between groups. Melatonin treatment was well tolerated and we did not observe significant differences in rates of side effects between the two groups. We concluded that melatonin administration during 6 months period is effective in reducing levels of serum pro-inflammatory cytokines and oxidative stress markers in patients with RRMS. These data support future studies evaluating the safety and effectiveness of melatonin supplementation in RRMS patients.

Melatonin ameliorates TNBS-induced colitis in rats through the melatonin receptors: involvement of TLR4/MyD88/NF-κB signalling pathway

AIM

The aim of the present study is to investigate the anti-inflammatory effect of melatonin in trinitrobenzene sulfonic acid (TNBS)-induced rat colitis through the inhibition of Toll-like receptor 4 (TLR4)/nuclear factor kappa B (NF-κB) signalling pathway and activation of melatonin receptor.

METHODS

Colitis was induced in Wistar rats by administration of 100 mg/kg TNBS dissolved in 0.25 ml of 50% ethanol solution using a flexible plastic rubber catheter into the colon via the anus. This resulted in incidence of colitis on the first day, and all treatments were conducted for 10 days after induction of colitis. Melatonin was administered intraperitoneally (i.p.) at doses of 1, 5, and 10 mg/kg/day. Luzindole (non-selective MT1/MT2 receptor antagonist) was administered i.p. at dose of 5 mg/kg/day 15 min prior to melatonin injection. During the experiment, animals were monitored for the appearance of diarrhoea, body weight loss, and rectal bleeding. Myeloid peroxidase enzyme and tumour necrosis factor-α (TNF-α) activities were detected by immunohistochemistry. The protein expression level of TLR4, myeloid differentiation factor 88 (MyD88), NF-κB p65, and inhibitor of kappa B (I-κB) were detected by western blotting analysis.

RESULTS

Treatment with melatonin improved weight loss, mucosal, and histological damage compared with TNBS group. In addition, melatonin decreased TNBS-induced up-regulation of TLR4, MyD88, and NF-κB p65, and increased down-regulation of I-κB proteins. On the other hand, the administration of luzindole resulted in the inhibition of melatonin effects.

CONCLUSIONS

It seems that the inhibition of TLR4/NF-κB signalling pathway may mediate the anti-inflammatory effects of melatonin in TNBS-induced rat colitis.