Melatonin and atopy: role in atopic dermatitis and asthma

Role of antioxidants supplementation in the treatment of atopic dermatitis: a critical narrative review

Atopic dermatitis (AD) is a chronic inflammatory skin disease characterized by itching, epidermal barrier dysfunction, and an unbalanced inflammatory reaction. AD pathophysiology involves a dysregulated immune response driven by T helper-2 cells. Many factors, including reactive oxygen species (ROS), are involved in AD pathogenesis by causing cellular damage and inflammation resulting in skin barrier dysfunction. This narrative review aims to provide a comprehensive overview of the role of natural molecules and antioxidant compounds, highlighting their potential therapeutic value in AD prevention and management. They include vitamin D, vitamin E, pyridoxine, Vitamin C, carotenoids, and melatonin. Some studies report a statistically significant association between antioxidant levels and improvement in AD, however, there are conflicting results in which antioxidant supplementation, especially Vitamin D, did not result in improvement in AD. Therefore, the clinical efficacy of these dietary nutritional factors in the treatment of AD needs to be further evaluated in clinical trials. Meanwhile, antioxidants can be incorporated into the management of AD patients in a personalized manner, tailored to the severity of the disease, comorbidities, and individual needs.

Peculiarities of melatonin levels in preterm infants

BACKGROUND

Melatonin plays an important role in organism functioning, child growth, and development. Of particular importance is melatonin for preterm infants. The aim of our research was to study the peculiarities of melatonin levels depending on various factors in preterm infants with gestational age (GA) of less than 34 weeks.

METHODS

The study involved 104 preterm infants with GA less than 34 weeks who were treated in the neonatal intensive care unit (NICU). The level of melatonin in urine samples was determined by an enzyme-linked immunosorbent assay.

RESULTS

Melatonin concentration was significantly lower in extremely and very preterm infants compared to moderate preterm (3.57 [2.10; 5.06] ng/ml vs. 4.96 [3.20; 8.42] ng/ml, p = 0.007) and was positively correlated with GA (Spearman r = 0.32; p < 0.001). Positive correlations were revealed between melatonin levels and Apgar scores at the 1st (Spearman r = 0.31; p = 0.001) and 5th minutes after birth (Spearman r = 0.35; p < 0.001). Melatonin levels were lower in newborns with respiratory distress syndrome (p = 0.011). No significant correlations were found between melatonin concentration and birth weight (Spearman r = 0.15; p = 0.130). There were no associations of melatonin concentrations and mode of delivery (p = 0.914), the incidence of early-onset sepsis (p = 0.370) and intraventricular hemorrhages (p = 0.501), and mechanical ventilation (p = 0.090). The results of multiple regression showed that gestational age at birth was the most significant predictor of melatonin level in preterm infants (B = 0.507; p = 0.001).

CONCLUSION

Gestational age and the Apgar score were associated with decreased melatonin levels in preterm infants. The level of melatonin in extremely and very preterm infants was lower compared to moderate preterm infants.

Influence of light at night on allergic diseases: a systematic review and meta-analysis

BACKGROUND

Allergic diseases impose a significant global disease burden, however, the influence of light at night exposure on these diseases in humans has not been comprehensively assessed. We aimed to summarize available evidence considering the association between light at night exposure and major allergic diseases through a systematic review and meta-analysis.

METHODS

We completed a search of six databases, two registries, and Google Scholar from inception until December 15, 2023, and included studies that investigated the influence of artificial light at night (ALAN, high vs. low exposure), chronotype (evening vs. morning chronotype), or shift work (night vs. day shift work) on allergic disease outcomes (asthma, allergic rhinitis, and skin allergies). We performed inverse-variance random-effects meta-analyses to examine the association between the exposures (ALAN exposure, chronotype, or shiftwork) and these allergic outcomes. Stratification analyses were conducted by exposure type, disease type, participant age, and geographical location along with sensitivity analyses to assess publication bias.

RESULTS

We included 12 publications in our review. We found that exposure to light at night was associated with higher odds of allergic diseases, with the strongest association observed for ALAN exposure (OR: 1.88; 95% CI: 1.04 to 3.39), followed by evening chronotype (OR: 1.35; 95% CI: 0.98 to 1.87) and exposure to night shift work (OR: 1.33; 95% CI: 1.06 to 1.67). When analyses were stratified by disease types, light at night exposure was significantly associated with asthma (OR: 1.62; 95% CI: 1.19 to 2.20), allergic rhinitis (OR: 1.89; 95% CI: 1.60 to 2.24), and skin allergies (OR: 1.11; 95% CI: 1.09 to 1.91). We also found that the association between light at night exposure and allergic diseases was more profound in youth (OR: 1.63; 95% CI: 1.07 to 2.48) than adults (OR: 1.30; 95% CI: 1.03 to 1.63). Additionally, we observed significant geographical variations in the association between light at night exposure and allergic diseases.

CONCLUSIONS

Light at night exposure was associated with a higher prevalence of allergic diseases, both in youth and adults. More long-term epidemiological and mechanistic research is required to understand the possible interactions between light at night and allergic diseases.

Life's Essential 8, genetic predisposition, and risk of incident adult-onset asthma: a prospective cohort study

BACKGROUND

Adult-onset asthma (AOA) and cardiovascular diseases shared common risk factors and similar pathophysiologic resemblances. The American Heart Association (AHA) unveiled the life's essential 8 (LE8) to promote cardiovascular health (CVH). This study aimed to assess the overall impact of LE8 implementation on AOA prevention.

METHODS

According to the guideline of AHA's Construct of CVH in 2022, LE8 score was calculated from 8 health status concerning diet, physical activity, nicotine exposure, sleep health, body mass index, blood lipids, blood glucose, and blood pressure. Cox proportional-hazards models were used to estimate effect sizes of associations between CVH, asthma genetic risk, and risk of incident AOA in participants selected from the UK Biobank study.

RESULTS

A total of 6180 incident AOA cases occurred in 249,713 participants during an average of 11.60 y' follow-up. A higher LE8 score was associated with a lower risk of incident AOA with a significant linear trend (P < 0.0001). Every standard deviation increment of LE8 was associated with a 17% (HR: 0.83; 95% CI: 0.81, 0.85) lower risk of incident AOA. Compared with participants with low-CVH score, participants with moderate (HR: 0.72; 95% CI: 0.67, 0.78) and high CVH scores (HR: 0.52; 95% CI: 0.47, 0.58) were associated with a lower risk of incident AOA (P-trend < 0.0001). No significant multiplicative or additive interaction was found between LE8 score and genetic risks. Stratified analysis showed a consistent association between CVH and risk of incident AOA across different asthma polygenic risk score (PRS) levels. Compared with participants with high PRS and low CVH, participants with low PRS and high CVH experienced the lowest risk (HR: 0.28; 95% CI: 0.23, 0.34) of incident AOA.

CONCLUSIONS

Our findings suggest that maintaining optimal CVH should be recommended as a preventive strategy for AOA, regardless of their asthma genetic risks.

The evaluation of melatonin levels in chronic spontaneous urticaria: A case control study

Background: Although sleep disturbance is known to be common in patients with chronic spontaneous urticaria (CSU), sleep hormone levels in the blood have never before been studied in CSU. Objective: In this study, we aimed to evaluate the serum melatonin levels in patients with CSU. Methods: For the patient group, 80 patients with recently diagnosed CSU, and, for the control group, 75 healthy controls (HC) were included. The study participants' melatonin levels were measured by using the enzyme-linked immunosorbent assay method. CSU disease activity was evaluated by using the urticaria activity score-7 (UAS-7), and the quality of life was assessed with the chronic urticaria quality of life questionnaire (CU-Q2oL). The patients with concomitant diseases likely to affect the melatonin levels or those using related medications were excluded from the study. Results: The patient group consisted of 53 female subjects (67%); the median (interquartile range) age was 34 years (27-43 years). The levels of melatonin were lower in the patients with CSU when compared with the HCs (p < 0.03). The melatonin levels had no significant relationship between UAS-7 and the total scores in CU-Q2oL (p > 0.05). However, a significant negative correlation in the melatonin levels was observed with questions 7 (overall sleep assessment) and 11 (difficulty in falling into sleep) in the CU-Q2oL (r = -0.55 [p < 0.001] and r = -0.62 [p < 0.001], respectively). Conclusion: The presence of low melatonin levels in the patients with CSU suggests that melatonin has a key regulatory role in the CSU development in addition to the deterioration in sleep quality. A new treatment strategy to increase the melatonin levels in CSU may be pursued in further studies to confirm our findings.

Investigation of possible relationship between atopic dermatitis and salivary biomarkers, stress, and sleep disorders

Atopic dermatitis (AD) is a chronic, relapsing, multifactorial inflammatory disease with genetic, environmental, and immunological characteristics. The quality of life and sleep of patients and their families are affected by AD, which triggers stress, described as one of the factors that worsens AD. Salivary biomarkers such as cortisol, alpha-amylase, chromogranin A, and melatonin have been associated with stress and sleep disturbances. Therefore, the evaluation of stress and sleep disorders using salivary biomarkers in AD patients is important. This review aims to describe the possible relationship between atopic dermatitis and stress, sleep disorders, and salivary biomarkers, seeking to contribute to better understanding and clinical management of AD. This descriptive study is characterized as a narrative literature review. A literature search was conducted of studies published in English and Portuguese between January 2012 and October 2022 that are available in electronic media from various databases, such as Scientific Electronic Library Online, Latin American and Caribbean Literature on Health Sciences, and PubMed. AD is associated with different degrees of impact on the lives of individuals who present with the disease. Psychological stress may induce changes in saliva composition and worsen AD; at the same time, the severity of the disease may be associated with emotional impact. Further studies are needed to assess and correlate AD severity, stress, and sleep disturbances with salivary biomarkers in order to better understand this association.

Mechanism of action and promising clinical application of melatonin from a dermatological perspective

Melatonin is the main neuroendocrine product in the pineal gland. Melatonin can regulate circadian rhythm-related physiological processes. Evidence indicates an important role of melatonin in hair follicles, skin, and gut. There appears to be a close association between melatonin and skin disorders. In this review, we focus on the latest research of the biochemical activities of melatonin (especially in the skin) and its promising clinical applications.

Melatonin in Dermatologic Allergic Diseases and Other Skin Conditions: Current Trends and Reports

Melatonin is the main hormone that regulates the sleep cycle, and it is mostly produced by the pineal gland from the amino acid tryptophan. It has cytoprotective, immunomodulatory, and anti-apoptotic effects. Melatonin is also one of the most powerful natural antioxidants, directly acting on free radicals and the intracellular antioxidant enzyme system. Furthermore, it participates in antitumor activity, hypopigmentation processes in hyperpigmentary disorders, anti-inflammatory, and immunomodulating activity in inflammatory dermatoses, maintaining the integrity of the epidermal barrier and thermoregulation of the body. Due predominantly to its positive influence on sleep, melatonin can be used in the treatment of sleep disturbances for those with chronic allergic diseases accompanied by intensive itching (such as atopic dermatitis and chronic spontaneous urticaria). According to the literature data, there are also many proven uses for melatonin in photoprotection and skin aging (due to melatonin's antioxidant effects and role in preventing damage due to DNA repair mechanisms), hyperpigmentary disorders (e.g., melasma) and scalp diseases (such as androgenic alopecia and telogen effluvium).

Melatonin and Sleep Disturbances in Children With Atopic Dermatitis

Objective

To evaluate the correlation between melatonin levels and sleep quality, based on the Children’s Sleep Habit Questionnaire (CSHQ), among children with atopic dermatitis (AD).

Methods

This was an analytic study with a cross-sectional design involving two groups, AD children as the case group and participants without AD as the control group, conducted at the Pediatric Dermatology Clinic of Dr. Hasan Sadikin Hospital, Bandung, Indonesia. Melatonin levels and CSHQ score in the case group were compared to that in the control group. Correlation analysis was performed between melatonin levels and sleep quality based on CSHQ in the case group.

Results

Participants in this study consisted of 19 children with moderate AD, (no patient with mild and severe AD was recruited), and 19 participants without AD. The mean CSHQ score in the case group was significantly higher than the control group (47.84 vs 36.79; p<0.05). The mean melatonin level in the case group was significantly lower than the control group (320.18 pg/mL vs 383.86 pg/mL; p<0.05). Comparative analysis was conducted using independent t-test. There was a significant Pearson’s correlation index between SCORAD and CSHQ (p<0.05). However, there was no correlation between melatonin levels and CSHQ, as well as between melatonin levels and SCORAD (p<0.05).

Conclusion

Children with moderate AD have impaired sleep quality and lower melatonin levels compared to controls. No correlation was found between melatonin levels and CSHQ, as well as melatonin levels and SCORAD, although there was a strong and significant correlation between SCORAD and CSHQ. Therefore, melatonin levels may not be the main cause of sleep disturbances in children with moderate AD.

Neuronal-Immune Cell Units in Allergic Inflammation in the Nose

Immune cells and immune-derived molecules, endocrine glands and hormones, the nervous system and neuro molecules form the combined tridirectional neuroimmune network, which plays a significant role in the communication pathways and regulation at the level of the whole organism and local levels, in both healthy persons and patients with allergic rhinitis based on an allergic inflammatory process. This review focuses on a new research paradigm devoted to neuronal-immune cell units, which are involved in allergic inflammation in the nose and neuroimmune control of the nasal mucociliary immunologically active epithelial barrier. The categorization, cellular sources of neurotransmitters and neuropeptides, and their prevalent profiles in constituting allergen tolerance maintenance or its breakdown are discussed. Novel data on the functional structure of the nasal epithelium based on a transcriptomic technology, single-cell RNA-sequencing results, are considered in terms of neuroimmune regulation. Notably, the research of pathogenesis and therapy for atopic allergic diseases, including recently identified local forms, from the viewpoint of the tridirectional interaction of the neuroimmune network and discrete neuronal-immune cell units is at the cutting-edge.

Melatonin Administration from 2000 to 2020 to Human Newborns with Hypoxic-Ischemic Encephalopathy

Hypoxic-ischemic encephalopathy (HIE) is the main cause of long-term neurodevelopmental morbidity in term born infants worldwide. Melatonin is a hormone with antioxidant and anti-inflammatory effects that make it a promising molecule for the treatment of perinatal asphyxia. Probably, the synergistic use of hypothermia associated with melatonin treatment may improve the neurological outcome in infants with HIE. In the past 20 years, the efficacy of melatonin in reducing oxidative stress has been demonstrated in animals; however, clinical trials with sufficient sample size of newborns are lacking to date. Since in 2000 we were among the first to study the neuroprotective properties of melatonin on infants, in this review, we want to summarize the advantages and limitations of the investigations conducted to date. KEY POINTS: · HIE is the main cause of morbidity in term born infants worldwide.. · Melatonin is a promising molecule for the treatment of perinatal asphyxia.. · This review summarizes advantages and limitations of the investigations conducted on melatonin..

Atopic dermatitis: pathomechanisms and lessons learned from novel systemic therapeutic options

Atopic dermatitis (AD) is a chronic, heterogenous, inflammatory skin disorder associated with a high skin-related health burden, typically starting in childhood and often persisting into adulthood. AD is characterized by a wide range of clinical phenotypes, reflecting multiple underlying pathophysiological mechanisms and interactions between genetics, immune system dysregulation, and environmental factors. In this review, we describe the diverse cellular and molecular mechanisms involved in AD, including the critical role of T cell-driven inflammation, primarily via T helper (Th) 2- and Th17-derived cytokines, many of which are mediated by the Janus kinase (JAK) signaling pathway. These local inflammatory processes interact with sensory neuronal pathways, contributing to the clinical manifestations of AD, including itch, pain, and sleep disturbance. The recent elucidation of the molecular pathways involved in AD has allowed treatment strategies to evolve from broad-acting systemic immunosuppressive therapies to more targeted agents, including JAK inhibitors and cytokine-specific biologic agents. Evidence from the clinical development of these targeted therapies has reinforced and expanded our understanding of the pathophysiological mechanisms underlying AD and holds promise for individualized treatment strategies tailored to specific AD subtypes.

Association of exposure to artificial light at night with atopic diseases: A cross-sectional study in college students

The impact of artificial light at night (ALAN) exposure on health has become increasingly prominent. However, little is known about the effect of ALAN exposure on atopic diseases. In this study, a cross-sectional analysis of incoming students was conducted in 5 geographically disperse universities which locate in Changsha (south), Wuhan (central), Xiamen (east), Urumchi (west), and Hohhot (north), respectively. All incoming students who consented to participate were recruited, followed by a health examination and a questionnaire survey. Prevalent atopic diseases were diagnosed by clinicians. Mean ALAN (nanoWatts/cm²/sr) during their adolescence was obtained from the remote sensing observed nighttime light data matching with their residence information, which was obtained from survey. Mixed generalized linear models (log-binomial) were used to estimate the associations, in terms of prevalence ratio (PR) with 95% confidence interval (CI). A total of 20106 participants were included in the analysis. Based on previous work, we chose factors including socioeconomic status, behavioural factors, major air pollutants, and air climatic parameters for adjustment. After full adjustment, the PR for atopic diseases was 1.35 (95% CI: 1.27-1.42; P < 0.001). The effect size of ALAN was the largest for asthma (PR = 1.80; 95% CI: 1.48-2.19; P < 0.001), followed by atopic rhinitis (PR = 1.42; 95% CI: 1.33-1.51; P < 0.001), and atopic dermatitis (PR = 1.20; 95% CI: 1.06-1.35; P = 0.003). Subgroup analyses by covariates showed consistent results. This study revealed that exposure to ALAN during adolescence may contribute to a higher risk of atopic diseases in young adulthood.

Topical Melatonin Exerts Immunomodulatory Effect and Improves Dermatitis Severity in a Mouse Model of Atopic Dermatitis

Oral melatonin supplement has been shown to improve dermatitis severity in children with AD, but the mechanism of the effect is unclear, and it is uncertain whether melatonin has a direct immunomodulatory effect on the dermatitis. Topical melatonin treatment was applied to DNCB-stimulated Balb/c mice, and gross and pathological skin findings, serum IgE, and cytokine levels in superficial lymph nodes were analyzed. Secretion of chemokines and cell proliferative response after melatonin treatment in human keratinocyte HaCaT cells were also studied. We found that in DNCB-stimulated Balb/c mice, topical melatonin treatment improved gross dermatitis severity, reduced epidermal hyperplasia and lymphocyte infiltration in the skin, and decreased IP-10, CCL27, IL-4, and IL-17 levels in superficial skin-draining lymph nodes. Melatonin also reduced cytokine-induced secretion of AD-related chemokines IP-10 and MCP-1 and decreased IL-4-induced cell proliferation in HaCaT cells. Melatonin seems to have an immunomodulatory effect on AD, with IP-10 as a possible target, and topical melatonin treatment is a potentially useful treatment for patients with AD.

Gekko gecko extract attenuates airway inflammation and mucus hypersecretion in a murine model of ovalbumin-induced asthma

ETHNOPHARMACOLOGICAL RELEVANCE

Gekko gecko is used as a traditional medicine for various diseases including respiratory disorders in northeast Asian countries, mainly Korea, Japan, and China.

AIM OF THE STUDY

Allergic asthma is a chronic respiratory disease caused by an inappropriate immune response. Due to the recent spread of coronavirus disease 2019, interest in the treatment of pulmonary disorders has rapidly increased. In this study, we investigated the anti-asthmatic effects of G. gecko extract (GGE) using an established mouse model of ovalbumin-induced asthma.

MATERIALS AND METHODS

To evaluate the anti-asthmatic effects of GGE, we evaluated histological changes and the responses of inflammatory mediators related to allergic airway inflammation. Furthermore, we investigated the regulatory effects of GGE on type 2 helper T (Th2) cell activation.

RESULTS

Administration of GGE attenuated asthmatic phenotypes, including inflammatory cell infiltration, mucus production, and expression of Th2 cytokines. Furthermore, GGE treatment reduced Th2 cell activation and differentiation.

CONCLUSIONS

These results indicate that GGE alleviates allergic airway inflammation by regulating Th2 cell activation and differentiation.

The preliminary investigation of potential response biomarkers to PAHs exposure on childhood asthma

BACKGROUND

Exposure to polycyclic aromatic hydrocarbons (PAHs) is a potential risk factor for asthma prevalence. This study aims to explore whether PAHs exposure is associated with childhood asthma by altering microbial diversity and metabolic profiles.

METHODS

Thirty children with asthma and 30 children as control in Nanjing, China were recruited. Urinary 1-hydroxypyrene (1-OHPyr) level was determined by UPLC-Orbitrap-MS as a PAHs exposure biomarker. Logistic regression was conducted to investigate the association between 1-OHPyr and childhood asthma. Microbial diversity was analyzed by 16S rRNA gene sequencing. Metabolic profiles were obtained by UPLC-Orbitrap-MS methods. Differential microbiota and metabolites were screened and selected as response biomarkers or intermediates. Mediation analysis was conducted to assess the association between PAHs and asthma mediated by intermediates.

RESULTS

Participating children with and without asthma aged 6.43 ± 2.23 years. The urinary 1-OHPyr level ranged from 0.10 to 1.51 μmol/mol (creatinine corrected) in the participants. The urinary 1-OHPyr level was associated with childhood asthma (OR = 7.21, 95% CI: 1.03-50.42 per 1 μmol/mol unit). Microbial diversity was decreased in the group with asthma and there was a significant shift in the abundance of Proteobacteria (at the phylum level), Veillonella and Prevotella (at the genus level). The enrichment pathway analysis showed that differentially expressed metabolites were involved in purine metabolism, amino acid metabolism, and lipid and fatty acid metabolism. The urinary 1-OHPyr level was associated with the abundance of Actinomyces sp. oral clone IO076 and 7-methylguanine that showed a mediation effect on the association between urinary 1-OHPyr levels and childhood asthma by mediation analysis.

CONCLUSIONS

Urinary 1-OHPyr exposure was associated with childhood asthma, microbial diversity, and metabolic profiles. Microbial diversity and metabolic profiles may be intermediates as response biomarkers to PAHs exposure in childhood asthma. Further research is needed to confirm these study results and determine the underlying mechanism.

The Effect of Short Sleep Duration on the Development of Asthma

Asthma is regarded as a heterogeneous disease with chronic airway inflammation and reversible airway limitation. Asthma itself and recurrent attacks of asthma can decrease sleep duration and increase the prevalence of short sleep duration. Systemic low-grade inflammation and obesity caused by short sleep duration have been known for a long time, which potentially affect the development of asthma. It would be interesting to study the interaction between short sleep duration and asthma. However, there are relatively few studies and no review about the association between short sleep duration and asthma. This article performed a review about the relationships between short sleep duration and asthmatic phenotype, laboratory tests, comorbidity, and clinical outcomes. Pooled studies about short sleep duration and asthma provided following four results: (1) compared with healthy sleep duration, short sleep duration seemingly increased the risk of central obesity in asthmatics; (2) short sleep duration potentially reduced the level of FeNO and increased lung function impairment in patients with asthma; (3) asthmatic comorbidities, mainly obesity and depression, were negatively associated with short sleep duration among asthmatics; (4) short sleep duration potentially increased the risks of asthma-related hospitalization and emergency care. However, almost all studies are based on subjective but not objective sleep duration. In addition, the study on sleep duration and cause-specific mortality in patients with asthma is relatively scant. Considering the effect of short sleep duration on the development of asthma, we recommend that periodic sleep monitoring for asthmatic management is very necessary.

Role of endogenous melatonin in pathophysiologic and oxidative stress responses to personal air pollutant exposures in asthmatic children

BACKGROUND

Heightening oxidative stress and inflammation is an important pathophysiological mechanism underlying air pollution health effects in people with asthma. Melatonin can suppress oxidative stress and inflammation in pulmonary and circulatory systems. However, the role of melatonin in the oxidative stress and physiological responses to air pollution exposure has not been examined in children with asthma.

METHODS

In this panel study of 43 asthmatic children (5-13 years old), each child had 4 clinic visits with a 2-week interval between two consecutive visits. At each visit, urine samples were collected and subsequently analyzed for 6-sulfatoxymelatonin (aMT6s) as a surrogate of circulating melatonin and for malondialdehyde (MDA) and 8-hydroxy-2'-deoxyguanosine (8-OHdG) as two biomarkers of systemic oxidative stress. At each clinic visit, children were measured for pulmonary function and fractional exhaled nitric oxide (FeNO, a marker of pulmonary inflammation). None of the children reported to have taking melatonin supplementation. Concentrations of indoor and ambient PM_2.5 and ozone (O₃) were combined with individual time-activity data to calculate personal air pollutant exposures.

RESULTS

We found that interquartile range increases in urinary MDA and 8-OHdG concentrations were associated with significantly increased urinary aMT6s concentrations by 73.4% (95% CI: 52.6% to 97.0%) and 41.7% (22.8% to 63.4%), respectively. Increases in daily personal exposure to O₃ and to PM_2.5 were each associated with increased urinary aMT6s concentrations. Increasing urinary aMT6s concentrations were associated with decreased FeNO and resonant frequency, indicating improved airway inflammation and lung elasticity, respectively.

CONCLUSION

The results suggest that systemic oxidative stress heightened by air pollution exposure may stimulate melatonin excretion as a defense mechanism to alleviate the adverse effects.

Therapeutic effects of melatonin on an ovalbumin-induced allergic rhinitis model in rats

OBJECTIVE

We aimed to investigate the therapeutic effects of melatonin in an experimental AR model.

METHODS

Thirty-two Wistar rats were randomised into four groups (n = 8 each). The experimental AR model was established in the saline (SF), ethanol, and melatonin groups via intraperitoneal (i.p.) injections and intranasal application of ovalbumin. The SF, ethanol, and melatonin groups received daily i.p. saline, 2% ethanol dissolved in saline, and 10 mg/kg melatonin dissolved in 2% ethanol and saline. The control group received the same amount of i.p. and intranasal saline. Total nasal symptom scores were recorded in all rats on days 1 (baseline), 15, 20, 25, and 30. Serum ovalbumin-specific IgE, IL-13, and melatonin levels were measured on days 1 (baseline), 15, and 30. The nasal mucosa of all rats was scored histopathologically.

RESULTS

The total nasal symptom scores and serum ovalbumin-specific IgE values of the SF, ethanol, and melatonin groups were significantly higher on day 15 than those of the control group. On day 30, the scores and serum ovalbumin-specific IgE values of the melatonin group were similar to those of the control, whereas the SF and ethanol groups had statistically higher scores. The histological scores of the SF and ethanol groups were significantly higher than those of the control and melatonin groups, but no significant difference was found between the melatonin and control groups.

CONCLUSION

Melatonin reduced total nasal symptom scores and serum ovalbumin-specific IgE levels and improved histological inflammation parameters in the ovalbumin-induced rat experimental AR model.

Alcohol and melatonin

Investigation of the pathogenesis of alcoholism in humans using different methodological approaches has facilitated detection of important biological factors of consequent metabolic diseases, endocrine disorders, and other medical conditions, such as alcoholic cardiomyopathy, alcoholic hypertension, heart and vascular lesions, alcoholic liver disease, alcoholic pancreatitis, etc. Alcohol abuse leads to damage to the nervous system, which can result in neurological and mental disorders, including alcoholic polyneuropathy, psychosis, and alcohol dementia. The complexity and versatility of the harmful effects of regular alcohol consumption on the human body can be considered in the perspective of a chronobiological approach, because alcohol is chronotoxic to biological processes. As a rhythm regulator, melatonin exerts a wide range of different effects: circadian rhythm regulation, thermoregulation, sleep induction, antioxidant, immunomodulatory, and anti-stress ones. This review presents from a chronobiological perspective the impact of melatonin on alcohol intoxication in terms of mental disorders, sleep and inflammation, hepatic injury, and mitochondrial function. It discusses the main clinical effects of melatonin on alcohol injury and the main targets as a therapy for alcohol disorders. Chronobiological effects of ethanol are related to melatonin suppression that has been associated with, among others, cancer risk. Exogenous melatonin seems to be a promising hepato- and immune-protector due to its antioxidant and anti-inflammatory properties, which in combination with other medicines makes it useful to prevent alcoholic organ damage. The reason for the scientific interest in melatonin as a treatment for alcoholism is obvious; the number of cases of this pathology that gives rise to metabolic syndrome, and its subsequent transformation into steatohepatitis, liver fibrosis, and cirrhosis, is increasing worldwide. Melatonin not only exerts antioxidant effects but it exerts various other effects contributing to the management of liver conditions. This review discusses the interaction between normal and pathological processes caused by alcohol consumption and the relationship between alcohol and melatonin in these conditions.

The melatonergic pathway and its interactions in modulating respiratory system disorders

Melatonin is a key intracellular neuroimmune-endocrine regulator and coordinator of multiple complex and interrelated biological processes. The main functions of melatonin include the regulation of neuroendocrine and antioxidant system activity, blood pressure, rhythms of the sleep-wake cycle, the retardation of ageing processes, as well as reseting and optimizing mitochondria and thereby the cells of the immune system. Melatonin and its agonists have therefore been mooted as a treatment option across a wide array of medical disorders. This article reviews the role of melatonin in the regulation of respiratory system functions under normal and pathological conditions. Melatonin can normalize the structural and functional organization of damaged lung tissues, by a number of mechanisms, including the regulation of signaling molecules, oxidant status, lipid raft function, optimized mitochondrial function and reseting of the immune response over the circadian rhythm. Consequently, melatonin has potential clinical utility for bronchial asthma, chronic obstructive pulmonary disease, lung cancer, lung vascular diseases, as well as pulmonary and viral infections. The integration of melatonin's effects with the alpha 7 nicotinic receptor and the aryl hydrocarbon receptor in the regulation of mitochondrial function are proposed as a wider framework for understanding the role of melatonin across a wide array of diverse pulmonary disorders.

A Pilot Randomized, Clinical Trial of the Anti-pruritus Effect of Melatonin in Patients with Chronic Liver Disease

Pruritus is one of the disturbing complications induced by chronic liver disease (CLD), bearing a negative impact on patient quality of life and potentially resulting in early liver transplants. Given the main role of the autotaxin enzyme in pruritus induced by CLD and the suppressive effects of melatonin on the expression of the autotaxin gene, this study was designed to evaluate the antipruritic effect of melatonin in patients with CLD. A double-blind, cross-over, randomized, placebo-controlled pilot trial was conducted on patients with CLD -induced pruritis. Patients were randomly assigned to two groups where they received melatonin 10-mg at night or placebo for 2 weeks. After a 2-week washout period, patients were then crossed over to the other group. The Visual Analog Scale (VAS) and the 12-Item Pruritus Severity Score (12-PSS) were used to assess patient response to therapy as the co-primary outcomes, while liver function tests were assayed too. Forty patients completed the study. The VAS score showed alleviation of 3.21 ± 2.24 (in pruritus) with melatonin (p-value <0.05). The study goal (a reduction of at least 20% in VAS) was achieved in 33 (82%) of study participants. In patients who received melatonin, the 12-PSS and Body Surface Area (BSA) affected by pruritus decreased on average 46.57% and 51.71%, respectively, with mood, sleep pattern and daily activity levels also demonstrating significant improvement (p-value < 0.05). Melatonin was found to be effective for managing pruritus in patients with CLD.

Role of Serum Melatonin and Oxidative Stress in Childhood Atopic Dermatitis: A Prospective Study

Background:

Many factors have been implicated in the pathogenesis of atopic dermatitis (AD) and recently the role of oxidative damage has been postulated.

Objectives:

To study the levels of oxidants and antioxidants including melatonin in the blood of children with AD and their association with the severity of AD.

Methods:

Thirty patients with atopic dermatitis, aged 6 months to 12 years, and equal number of age and sex-matched controls were included. Clinical characteristics and baseline severity assessment using SCORAD (scoring atopic dermatitis) severity index were noted. Blood superoxide dismutase, blood glutathione peroxidase, serum malondialdehyde, and serum melatonin levels were measured in cases and controls and results were compared.

Results:

The serum levels of malondialdehyde and melatonin were significantly higher among the cases compared to controls. The blood levels of superoxide dismutase and glutathione peroxidase were higher in cases but the difference with controls was not statistically significant. There was no significant correlation between these markers and the severity of the disease.

Conclusions:

Oxidative stress was increased in cases of childhood AD compared to the control group in this study. No correlation between oxidative stress and the severity of the disease was found. Larger studies are warranted.

Sleep Disturbances and Atopic Dermatitis: Relationships, Methods for Assessment, and Therapies

Atopic dermatitis is one of the most common chronic inflammatory skin conditions and is associated with sleep disturbances in 47% to 80% of children and 33% to 90% of adults. Herein, we review the literature on sleep disturbances experienced by patients with atopic dermatitis, as well as the mechanisms that may underlie this. We present subjective and objective methods for measuring sleep quantity and quality and discuss strategies for management. Unfortunately, the literature on this topic remains sparse, with most studies evaluating sleep as a secondary outcome using subjective measures. The development of portable, at-home methods for more objective measures offers new opportunities to better evaluate sleep disturbances in atopic dermatitis research studies and in clinical practice.

Metabolomics Profiling and Diagnosis Biomarkers Searching for Drug-Induced Liver Injury Implicated to Polygonum multiflorum: A Cross-Sectional Cohort Study

Aim: The diagnosis of drug-induced liver injury (DILI) remains a challenge and the cases of Polygonum multiflorum Thunb. (PM) induced DILI (PM-DILI) have received much attention This study aimed to identify a simple and high-efficiency approach to PM-DILI diagnosis via metabolomics analysis.

Methods: Plasma metabolites in 13 PM-DILI patients were profiled by liquid chromatography along with high-resolution mass spectrometry. Meanwhile, the metabolic characteristics of the PM-DILI were compared with that of autoimmune hepatitis (AIH), hepatitis B (HBV), and healthy volunteers.

Results: Twenty-four metabolites were identified to present significantly different levels in PM-DILI patients compared with HBV and AIH groups. These metabolites were enriched into glucose, amino acids, and sphingolipids metabolisms. Among these essential metabolites, the ratios of P-cresol sulfate vs. phenylalanine and inosine vs. bilirubin were further selected using a stepwise decision tree to construct a classification model in order to differentiate PM-DILI from HBV and AIH. The model was highly effective with sensitivity of 92.3% and specificity of 88.9%.

Conclusions: This study presents an integrated view of the metabolic features of PM-DILI induced by herbal medicine, and the four-metabolite decision tree technique imparts a potent tool in clinical diagnosis.

Individual circadian preference (chronotype) is associated with asthma and allergic symptoms among adolescents

Circadian rhythm is an endogenously driven cyclical process that regulates most of our bodily functions, such as sleep–wakefulness cycle, metabolism, and a wide range of cellular, molecular and behavioural processes. Chronotype, or an individual's preferred time of sleep and activity, is one of the major internal cues that helps to harmonise one's biological events according to its circadian timing [1]. Three major variations of chronotype exist among humans, those who prefer to wake up early and sleep early at night (known as morning types or “larks”), those who prefer late sleep at night and late waking up in the morning (referred to as evening type or “owls”) and those who remain in between (intermediate type) [1].

Individual preference of sleep and activity (chronotype) might play an important role on asthma and allergic diseases in adolescents: this link underscores a potential plausible behavioural intervention for asthma and allergic diseases in young populationhttps://bit.ly/2THta9I

Use of Melatonin in Oxidative Stress Related Neonatal Diseases

Reactive oxygen species have a crucial role in the pathogenesis of perinatal diseases. Exposure to inflammation, infections, or high oxygen concentrations is frequent in preterm infants, who have high free iron levels that enhance toxic radical generation and diminish antioxidant defense. The peculiar susceptibility of newborns to oxidative stress supports the prophylactic use of melatonin in preventing or decreasing oxidative stress-mediated diseases. Melatonin, an effective direct free-radical scavenger, easily diffuses through biological membranes and exerts pleiotropic activity everywhere. Multiple investigations have assessed the effectiveness of melatonin to reduce the “oxygen radical diseases of newborn” including perinatal brain injury, sepsis, chronic lung disease (CLD), and necrotizing enterocolitis (NEC). Further studies are still awaited to test melatonin activity during perinatal period.

Melatonin and oxidative stress in melasma - an unexplored territory; a prospective study

BACKGROUND

Melasma, an acquired disorder of hyperpigmentation, is the most common pigmentary disorder in India. Many factors are implicated in the pathogenesis, and recently the role of oxidative damage including melatonin has been postulated. This study was undertaken to evaluate the role of oxidative stress and serum melatonin in pathogenesis of melasma.

METHODS

Seventy-five patients with melasma and an equal number of age and sex-matched controls were included in the study. Clinical characteristics were noted, and baseline severity assessment using modified Melasma Area and Severity Index (MASI) was done in all patients. Serum melatonin, catalase, protein carbonyl, and nitric oxide levels were measured and compared between cases and controls.

RESULTS

The serum levels of melatonin and catalase were significantly lower among the cases as compared to controls, while the serum levels of protein carbonyl and nitric oxide were significantly higher in cases compared to controls. There was no statistically significant correlation between these markers of oxidative stress and severity of the disease.

CONCLUSIONS

Oxidative stress is increased in patients with melasma compared to the control group in this study. A state of melatonin deficit also exists in patients with melasma. No correlation between the oxidative stress and severity of the disease was found. Further and larger studies including therapeutic trials with powerful antioxidants are warranted.

Protective Effects of Melatonin on the Skin: Future Perspectives

When exposed to hostile environments such as radiation, physical injuries, chemicals, pollution, and microorganisms, the skin requires protective chemical molecules and pathways. Melatonin, a highly conserved ancient molecule, plays a crucial role in the maintenance of skin. As human skin has functional melatonin receptors and also acts as a complete system that is capable of producing and regulating melatonin synthesis, melatonin is a promising candidate for its maintenance and protection. Below, we review the studies of new metabolic pathways involved in the protective functions of melatonin in dermal cells. We also discuss the advantages of the topical use of melatonin for therapeutic purposes and skin protection. In our view, endogenous intracutaneous melatonin production, together with topically-applied exogenous melatonin and its metabolites, represent two of the most potent defense systems against external damage to the skin.

Prognostic Impact of Melatonin Receptors MT1 and MT2 in Non-Small Cell Lung Cancer (NSCLC)

Background: Several studies have investigated the inhibitory effect of melatonin on lung cancer cells. There are no data available on the prognostic impact of melatonin receptors MT1 and MT2 in non-small cell lung cancer (NSCLC). Materials and Methods: Immunohistochemical studies of MT1 and MT2 were conducted on NSCLC (N = 786) and non-malignant lung tissue (NMLT) (N = 120) using tissue microarrays. Molecular studies were performed on frozen fragments of NSCLC (N = 62; real time PCR), NMLT (N = 24) and lung cancer cell lines NCI-H1703, A549 and IMR-90 (real time PCR, western blot). Results: The expression of both receptors was higher in NSCLC than in NMLT. Higher MT1 and MT2 expression levels (at protein and mRNA) were noted in squamous cell carcinomas (SCC) compared to adenocarcinomas (AC). MT1 immunoexpression decreased as both the tumour size and the cancer stage increased in the whole cohort, while MT2 decreased as the cancer stage increased, with lymph node involvement (in the whole study group) and increasing malignancy grade (in SCC). Higher expression of MT2 was associated with a favorable prognosis. MT2 was an independent prognostic factor for overall survival (OS) in all analyzed NSCLC and in smoking patients. Conclusions: Our observations may point to the potential prognostic significance of MT2 in NSCLC.

Melatonin decreases and cytokines increase in women with placental insufficiency

Purpose: To investigate the levels of melatonin, proinflammatory and anti-inflammatory cytokines in pregnant women with placental insufficiency (PI).Materials and Methods: The PI was manifested as the intrauterine growth restriction syndrome of fetus (IUGR) in the third pregnancy trimester. The control group consisted of 20 women with uncomplicated pregnancy in the same term. The blood concentrations of melatonin, proinflammatory cytokines, such as tumor necrotizing factor-α (TNF-α), interleukin-1-β (IL-1-β), interleukin-6 (IL-6), and anti-inflammatory cytokines, such as interleukin-4 (IL-4), and interleukin-10 (IL-10), were studied.Results: The concentration of melatonin was found to decrease significantly if pregnancy was complicated by intrauterine fetal growth retardation (study group -126.87 ± 14.87 pg/ml, control group -231.25 ± 21.56 pg/ml, p < .001). The levels of proinflammatory cytokines in the study group were significantly higher as compared with the control group (TNF-α: study group -10.05 ± 1.35 pg/ml, control group -5.60 ± 1.50 pg/ml, p < .05; IL-1-β: study group -14.67 ± 2.13 pg/ml, control group -3.96 ± 0.92 pg/ml, p < .001; IL-6: study group -6.91 ± 0.99 pg/ml, control group -2.69 ± 0.99 pg/ml, p < .05). The same is true about anti-inflammatory cytokines (IL-4: study group -5.97 ± 0.50 pg/ml, control group -3.74 ± 0.62 pg/ml, p < .05; IL-10: study group -11.40 ± 1.50 pg/ml, control group -4.70 ± 3.20 pg/ml, p < .001). A moderate negative correlation between melatonin and IL-1-β in the group with PI (r = -0.3776, p = .0097), a closed negative correlation between the same indexes in the control group (r = -0.6785, p = .001), and a moderate negative correlation between melatonin and TNF-α (r = -0.4908, p = .02) were found.Conclusions: The blood level of melatonin significantly decreases in case of placental insufficiency, manifested as intrauterine fetal growth restriction. Strengthening of the proinflammatory immunity shown as the increasing of the levels of TNF-α, IL-1-β, and IL-6 levels is also present in case of IUGR. Increase of the serum concentration of the anti-inflammatory cytokines, such as IL-4 and IL-10, in our opinion, can be explained by activation of compensatory mechanisms, which decrease the risk of premature labor.

The effects of melatonin administration on disease severity and sleep quality in children with atopic dermatitis: A randomized, double-blinded, placebo-controlled trial

BACKGROUND

The aim of this clinical trial was to determine the effects of melatonin administration on disease severity and sleep quality in children diagnosed with atopic dermatitis (AD).

METHODS

This randomized, double-blinded, placebo-controlled trial was conducted by recruiting 70 patients, aged 6-12 years, who had been diagnosed with AD. Study participants were randomly allocated into two intervention groups to receive either 6 mg/d melatonin supplements or placebo (n = 35 each group) for 6 weeks. Severity of disease was assessed using the scoring atopic dermatitis (SCORAD) and objective SCORAD indices. Sleep quality was evaluated by completing the Children's Sleep Habits Questionnaire (CSHQ).

RESULTS

Following 6 weeks of intervention, melatonin supplementation significantly improved SCORAD index (β -3.55; 95% CI, -6.11, -0.98; P = 0.007), objective SCORAD index (β -3.23; 95% CI, -5.08, -1.38; P = 0.001), serum total IgE levels (β -153.94 ku/L; 95% CI, -260.39, -47.49; P = 0.005), and CSHQ scores (β -2.55; 95% CI, -4.34, -0.75; P = 0.006). However, melatonin had no significant impact on pruritus scores, high-sensitivity C-reactive protein (hs-CRP), sleep-onset latency, total sleep time, weight, and BMI compared with placebo.

CONCLUSIONS

Overall, melatonin supplementation had beneficial effects on disease severity, serum total IgE levels, and CSHQ among children diagnosed with AD.

Sleep disorders and atopic dermatitis: A 2-way street?

Sleep disturbance is very common in patients with atopic dermatitis (AD) and is a major factor leading to impaired quality of life. Sleep disturbance is often viewed as one of the symptoms of AD and one of the measures of disease severity. In this review we describe a variety of sleep disorders associated with AD and a wide range of effect that sleep disorders have on patients with AD. We also discuss our current understanding of the mechanism of sleep disturbance in patients with AD. The relationship between sleep disorders and AD might be bidirectional and could form a vicious cycle. Therefore we suggest viewing sleep disorders as a comorbidity of AD for which regular screening and bidirectional management strategies are indicated, with equal focus on maintaining disease control and implementing specific strategies to improve sleep.

Managing sleep disturbances in children with atopic dermatitis

Atopic dermatitis is a chronic, pruritic inflammatory disease that often disrupts sleep in severely affected children, but there are limited studies to guide clinical management of these sleep problems. Disease control is crucial in improving sleep, but additional sleep aids may sometimes be helpful in decreasing scratching during the night. This review discusses the benefits and limitations of potential therapeutic agents available to manage sleep disturbances in children with atopic dermatitis.

Melatonin: A Cutaneous Perspective on its Production, Metabolism, and Functions

Melatonin, an evolutionarily ancient derivative of serotonin with hormonal properties, is the main neuroendocrine secretory product of the pineal gland. Although melatonin is best known to regulate circadian rhythmicity and lower vertebrate skin pigmentation, the full spectrum of functional activities of this free radical-scavenging molecule, which also induces/promotes complex antioxidative and DNA repair systems, includes immunomodulatory, thermoregulatory, and antitumor properties. Because this plethora of functional melatonin properties still awaits to be fully appreciated by dermatologists, the current review synthesizes the main features that render melatonin a promising candidate for the management of several dermatoses associated with substantial oxidative damage. We also review why melatonin promises to be useful in skin cancer prevention, skin photo- and radioprotection, and as an inducer of repair mechanisms that facilitate the recovery of human skin from environmental damage. The fact that human skin and hair follicles not only express functional melatonin receptors but also engage in substantial, extrapineal melatonin synthesis further encourages one to systematically explore how the skin's melatonin system can be therapeutically targeted in future clinical dermatology and enrolled for preventive medicine strategies.

Circadian rhythm in atopic dermatitis-Pathophysiology and implications for chronotherapy

Circadian rhythm is a biological clock that controls a wide range of physiological functions throughout the body, including various skin functions. A 24-h diurnal cycle, governed by an endogenous clock in the brain, largely controls cutaneous diurnal rhythm, which external factors, including temperature, humidity, diet, and stress, also modulate locally. Circadian rhythm influences cutaneous blood flow and properties of skin barrier function, such as transepidermal water loss and capacitance, and has important implications in atopic dermatitis (AD). This review explores how aberrations in circadian rhythm may play a role in the pathogenesis of AD and proposes implementation of chronotherapy to improve treatment outcomes in patients with AD.

Association between Allergies and Hypercholesterolemia: A Systematic Review

BACKGROUND

There is controversy in the literature regarding the potential relationship between atopic predisposition (AP) and serum cholesterol levels. To this purpose, we reviewed human studies that investigated this possible link.

METHODS

Following PRISMA guidelines, a literature search of PubMed and Science Direct for peer-reviewed journal articles in English from January 2003, with updates through to August 2016, was conducted. Relevant publications were reviewed that included pediatric and adult populations. Information on the study design, sample, intervention, comparators, outcome, time frame, and risk of bias were abstracted for each article.

RESULTS

Of 601 reviewed reports, 18 were included in this systematic review. Fifteen studies assessed the relationship between AP and serum cholesterol levels. Due to the lack both of observational and cross-sectional studies from the literature search at this time (only 8 studies also analyzed confounding factors) there is a high possibility of confounding variables (familial and genetic predisposition, age, gender, BMI, comorbidity, and medication status) that could not be ruled out.

CONCLUSION

Existing studies are heterogeneous, making it difficult to draw broad conclusions. Future studies and more detailed analyses, considering confounding variables and including a larger and homogeneous population, are needed to strengthen the argument for a link between lipid metabolism and atopy.

Premedication with melatonin vs midazolam: efficacy on anxiety and compliance in paediatric surgical patients

Preoperative anxiety is a major problem in paediatric surgical patients. Melatonin has been used as a premedicant agent and data regarding effectiveness are controversial. The primary outcome of this randomized clinical trial was to evaluate the effectiveness of oral melatonin premedication, in comparison to midazolam, in reducing preoperative anxiety in children undergoing elective surgery. As secondary outcome, compliance to intravenous induction anaesthesia was assessed. There were 80 children undergoing surgery randomly assigned, 40 per group, to receive oral midazolam (0.5 mg/kg, max 20 mg) or oral melatonin (0.5 mg/kg, max 20 mg). Trait anxiety of children and their mothers (State-Trait Anxiety Inventory) at admission, preoperative anxiety and during anaesthesia induction (Modified Yale Pre-operative Anxiety Scale), and children's compliance with anaesthesia induction (Induction Compliance Checklist) were all assessed. Children premedicated with melatonin and midazolam did not show significant differences in preoperative anxiety levels, either in the preoperative room or during anaesthesia induction. Moreover, compliance during anaesthesia induction was similar in both groups.

CONCLUSIONS

This study adds new encouraging data, further supporting the potential use of melatonin premedication in reducing anxiety and improving compliance to induction of anaesthesia in children undergoing surgery. Nevertheless, further larger controlled clinical trials are needed to confirm the real effectiveness of melatonin as a premedicant agent in paediatric population. What is Known: • Although midazolam represents the preferred treatment as a premedication for children before induction of anaesthesia, it has several side effects. • Melatonin has been successfully used as a premedicant agent in adults, while data regarding effectiveness in children are controversial. What is New: • In this study, melatonin was as effective as midazolam in reducing children's anxiety in both preoperative room and at induction of anaesthesia.

Melatonin: Possibilities for use in the treatment of asthma

Asthma is a serious health problem affecting all age groups. Melatonin or its agonists are commonly used to treat many diseases, but there are conflicting data on asthma therapy. This paper analyzes researches on the possible use of melatonin in the therapy of asthma. Melatonin is a potent antioxidant and a vasodilator, but in some experiments, it can act as a pro-oxidant and a vasoconstrictor, which may depend on the duration of use. It has been suggested that circadian rhythms should be corrected in asthmatics to optimize the desired effects of drugs and to reduce the severity of their adverse reactions. Disordered diurnal variations in the salivary levels of melatonin and cortisol are detectable in patients with asthma and may be implicated in its pathogenesis. In addition, the conflicting data on the effect of melatonin on the development of asthma are associated with an incomplete view of the factors influencing the level of melatonin. Thus, to study the effects of melatonin, it is necessary to take into account the greatest possible factors that may influence the level of melatonin and the course of asthma: a daily diet in terms of the use of caffeine, alcohol, sleep-wakefulness pattern, sleep quality proper, and drowsiness during the daytime, social burden, the level of anxiety and stress resistance, and to investigate the levels of endogenous melatonin or its derivatives, immune status, oxidative stress intensity, etc. Obviously, the use of melatonin in the therapy of asthma can be considered, by applying a personalized approach.

Atopy and autoimmune thyroid diseases: melatonin can be useful?

Recently, there has been growing interest in the relationship between allergic and autoimmune diseases. Allergy and autoimmunity can be considered two potential outcomes of dysregulated immunity and analysis of literature data shows a strong positive association between a history of Th2-mediated allergic disorders and Th1-mediated autoimmune disorders.

Autoimmune thyroid diseases are the most common of all autoimmune pathological conditions.

Currently, the mechanisms explaining an association among atopy, autoimmunity, and thyroid diseases are not fully understood.

There are data in literature pointing to the relationship between melatonin and thyroid activity. Several studies have suggested a paracrine role for this molecule in the regulation of thyroid activity, documenting that administration, as an antioxidant, in thyroid tissues under conditions of increased oxidative stress, could be helpful to reduce the oxidative processes involved in autoimmune thyroid diseases.

Although thyroid autoimmunity has been regularly associated with atopic conditions in children, the possible protective role of melatonin has not yet been investigated.

This review summarizes what is known regarding the connection between atopy and autoimmune thyroid diseases, and analyses the probable beneficial action of melatonin.

Evaluation of Oxidant-Antioxidant Balance in Children with Atopic Dermatitis: A Case-Control Study

BACKGROUND

Increased reactive oxygen species (ROS) and oxidative stress (OS) has been reported in many allergic and inflammatory skin diseases, including urticaria, psoriasis, and atopic dermatitis (AD). Melatonin is a hormone secreted from the pineal gland and is a potent antioxidant.

OBJECTIVE

The aim of the study was to measure serum antioxidant melatonin, oxidants of nitric oxide (NO), and malondialdehyde levels to calculate the serum oxidant-antioxidant balance based on the NO/melatonin and malondialdehyde/melatonin ratios and to determine the correlation with the disease severity in children with AD.

METHODS

Seventy-three children with AD and 67 healthy controls were included in the study. The clinical diagnosis of AD was based on the diagnostic criteria of Hanifin-Rajka. The severity of AD was evaluated by the scoring AD (SCORAD) index, and atopy was determined by skin prick tests (SPTs) with commercial extracts. The OS-related parameters of serum melatonin, NO, malondialdehyde, and the NO/melatonin and malondialdehyde/melatonin ratios were calculated and compared with the results of healthy controls.

RESULTS

Serum melatonin levels were higher (p < 0.0001) and serum NO levels and the NO/melatonin and malondialdehyde/melatonin ratios were lower in children with AD than in healthy controls (p = 0.045, p < 0.0001, p < 0.0001, respectively). There was no difference between children with AD and healthy controls in terms of serum malondialdehyde levels (p = 0.119). Serum melatonin levels were significantly lower in severe AD than in mild AD (p = 0.012). However, in terms of serum melatonin levels, there was no difference between mild and moderate AD (p = 0.742) and moderate to severe AD (p = 0.301). There was no significant difference in serum NO and malondialdehyde levels and NO/melatonin and malondialdehyde/melatonin ratios among children with mild, moderate, and severe AD (p > 0.05). A negative correlation was found between serum melatonin levels and the SCORAD index (r = -0.252, p = 0.031), and a positive correlation was found between NO/melatonin and malondialdehyde/melatonin ratios (r = 0.511, p < 0.0001). There was no statistically significant relationship between age (≤24 or >24 months), disease duration (≤6 or >6 months), and sex for the OS-related parameters (p > 0.05).

CONCLUSION

The serum oxidant-antioxidant balance was impaired in children with AD. Serum melatonin levels were higher in children with AD; however, this was negatively correlated with disease severity. Serum NO levels and NO/melatonin and malondialdehyde/melatonin ratios were lower in children with AD than in healthy controls. Melatonin might be used as a promising antioxidant to evaluate disease severity in children with AD. Thus, further studies are needed to clarify the role of melatonin in AD pathogenesis.

Melatonin pharmacokinetics after transdermal administration changes according to the time of the day

Melatonin is a neurohormone with multiple and different actions, such as chronobiotic or antioxidant. Melatonin is usually orally administered, but dermal administration is also useful in dermatological diseases or as adjuvant to certain skin treatments. Here, we studied the variability of the pharmacokinetics of melatonin and its metabolite AFMK, when melatonin is transdermally administered to Hairless rat at two different times of day (Zeitgeber Time 4 (ZT4) and ZT16). Moreover, in order to obtain the bioavailability, kinetics after intravenous administration was also studied. In addition, a permeation study was carried out, at both ZTs, to test the amount of melatonin retained in the skin after transdermal administration. Results showed that pharmacokinetic parameters of melatonin administered exogenously depended on the time of the day. When intravenous data were fitted to a compartmental model, the extrapolated plasma concentration at time 0 and the area under the curve were higher at ZT4, while clearance, volumes of central and peripheral compartments and volume of distribution at the steady state were higher at ZT16. Transdermal administration was best fitted to a one-compartment model and t_max, half-life of absorption and area under the curve showed higher values at ZT4, while the absorption rate and constant of absorption were higher at ZT16. AFMK was detected in all cases, but no differences between the two ZTs were observed. Transdermal administration showed better bioavailability also at ZT4. Results indicate that time of day is a variable that should be taken into account when melatonin is transdermally administered.

DNA methylation within melatonin receptor 1A (MTNR1A) mediates paternally transmitted genetic variant effect on asthma plus rhinitis

BACKGROUND

Asthma and allergic rhinitis (AR) are common allergic comorbidities with a strong genetic component in which epigenetic mechanisms might be involved.

OBJECTIVE

We aimed to identify novel risk loci for asthma and AR while accounting for parent-of-origin effect.

METHODS

We performed a series of genetic analyses, taking into account the parent-of-origin effect in families ascertained through asthma: (1) genome-wide linkage scan of asthma and AR in 615 European families, (2) association analysis with 1233 single nucleotide polymorphisms (SNPs) covering the significant linkage region in 162 French Epidemiological Study on the Genetics and Environment of Asthma families with replication in 154 Canadian Saguenay-Lac-Saint-Jean asthma study families, and (3) association analysis of disease and significant SNPs with DNA methylation (DNAm) at CpG sites in 40 Saguenay-Lac-Saint-Jean asthma study families.

RESULTS

We detected a significant paternal linkage of the 4q35 region to asthma and allergic rhinitis comorbidity (AAR; P = 7.2 × 10(-5)). Association analysis in this region showed strong evidence for the effect of the paternally inherited G allele of rs10009104 on AAR (P = 1.1 × 10(-5), reaching the multiple-testing corrected threshold). This paternally inherited allele was also significantly associated with DNAm levels at the cg02303933 site (P = 1.7 × 10(-4)). Differential DNAm at this site was found to mediate the identified SNP-AAR association.

CONCLUSION

By integrating genetic and epigenetic data, we identified that a differentially methylated CpG site within the melatonin receptor 1A (MTNR1A) gene mediates the effect of a paternally transmitted genetic variant on the comorbidity of asthma and AR. This study provides a novel insight into the role of epigenetic mechanisms in patients with allergic respiratory diseases.

Mechanism of Sleep Disturbance in Children with Atopic Dermatitis and the Role of the Circadian Rhythm and Melatonin

Sleep disturbance is common in children with atopic dermatitis (AD). It is a major factor leading to impaired quality of life in these patients and could have negative effects on neurocognitive function and behavior. However, the pathophysiology of sleep disturbance in children with AD is poorly understood, and there is no consensus on how to manage sleep problems in these patients. Pruritus and scratching could lead to sleep disruption but is unlikely the sole etiology. The circadian rhythm of cytokines, the immune system, and skin physiology such as transcutaneous water loss and skin blood flow might also play a role. Recent studies have suggested that melatonin could also be involved due to its multiple effects on sleep, immunomodulation, and anti-oxidant ability. Environmental factors should also be considered. In this review, we summarize the current understanding of the pathophysiology of sleep disturbance in children with AD, and discuss possible therapeutic implications.

Oxidative Stress in Atopic Dermatitis

Atopic dermatitis (AD) is a chronic pruritic skin disorder affecting many people especially young children. It is a disease caused by the combination of genetic predisposition, immune dysregulation, and skin barrier defect. In recent years, emerging evidence suggests oxidative stress may play an important role in many skin diseases and skin aging, possibly including AD. In this review, we give an update on scientific progress linking oxidative stress to AD and discuss future treatment strategies for better disease control and improved quality of life for AD patients.

Potential Utility of Melatonin in Preeclampsia, Intrauterine Fetal Growth Retardation, and Perinatal Asphyxia

AIM

Reactive oxygen species play an important role in the pathogenesis of several diseases during gestation and the perinatal period. During pregnancy, increased oxygen demand augments the rate of production of free radicals. Oxidative stress is involved in pregnancy disorders including preeclampsia and intrauterine fetal growth retardation (IUGR). Moreover, increased levels of oxidative stress and reduced antioxidative capacities may contribute to the pathogenesis of perinatal asphyxia. Melatonin, an efficient antioxidant agent, diffuses through biological membranes easily and exerts pleiotropic actions on every cell and appears to be essential for successful gestation. This narrative review summarizes current knowledge concerning the role of melatonin in reducing complications during human pregnancy and in the perinatal period.

RESULTS

Melatonin levels are altered in women with abnormally functioning placentae during preeclampsia and IUGR. Short-term melatonin therapy is highly effective and safe in reducing complications during pregnancy and in the perinatal period. Because melatonin has been shown to be safe for both mother and fetus, it could be an attractive therapy in pregnancy and is considered a promising neuroprotective agent in perinatal asphyxia.

CONCLUSION

We believe that the use of melatonin treatment during the late fetal and early neonatal period might result in a wide range of health benefits, improved quality of life, and may help limit complications during the critical periods prior to, and shortly after, delivery.