The therapeutics of melatonin: a paediatric perspective

Melatonin protect against pregabalin-induced gonadotoxicity via anti-oxidative, anti-inflammatory, anti-apoptotic, enzymatic and hormonal regulatory mechanisms in rats

BACKGROUND

The therapeutic value of pregabalin in managing various pathological states, such as sleep, anxiety, and bipolar disorders, fibromyalgia, epilepsy, and others, cannot be overstated. Nevertheless, the gonadotoxicity of this drug remains a concern. In contrast, melatonin, an endogenous hormone, is known for its beneficial effects on reproductive tissues following various insults. Thus, this study aimed to examine the impact of melatonin on male Wistar rats exposed to pregabalin.

METHODS

A total of sixty male Wistar rats, weighing between 120 and 140 g, were randomly assigned to six groups, with each group consisting of ten rats. The control group was given 0.5 ml of normal saline orally, whereas melatonin was administered alone at 10 mg/kg/BW, and pregabalin was delivered at low and high doses of 150 and 300 mg/kg/BW orally, respectively. At the specified dosages, rats were also treated simultaneously with low and high doses of pregabalin in combination with melatonin. All treatments lasted for 56 days. Biomarkers were assayed in the testicular and epididymal tissues, while hormones were assayed in the serum.

RESULTS

Pregabalin treatment resulted in notable decreases in the percentage body weight change, testicular weight, relative testicular weight, FSH, LH, testosterone, 3β-HSD, 17β-HSD, SOD, catalase, and GSH, as compared to the control group. However, these effects were mitigated in the groups administered melatonin in conjunction with pregabalin. Pregabalin treatment also caused significant elevations in lactate, pyruvate, LDH, GGT, MDA, caspase, IL-1β, NF-κB, and TNF-α, and distorted testicular histoarchitecture, but these effects were blunted in the group co-administered with pregabalin and melatonin. The histological findings paralleled the biochemical assays.

CONCLUSION

Conclusively, melatonin has a protective effect against pregabalin-induced gonadotoxicity through anti-oxidative, anti-inflammatory, anti-apoptotic, enzymatic, and hormonal regulatory mechanisms.

CLINICAL TRIAL NUMBER

Not applicable.

Sleep's role in the development and resolution of adolescent depression

Two adolescent mental health fields - sleep and depression - have advanced largely in parallel until about four years ago. Although sleep problems have been thought to be a symptom of adolescent depression, emerging evidence suggests that sleep difficulties arise before depression does. In this Review, we describe how the combination of adolescent sleep biology and psychology uniquely predispose adolescents to develop depression. We describe multiple pathways and contributors, including a delayed circadian rhythm, restricted sleep duration and greater opportunity for repetitive negative thinking while waiting for sleep. We match each contributor with evidence-based sleep interventions, including bright light therapy, exogenous melatonin and cognitive-behaviour therapy techniques. Such treatments improve sleep and alleviate depression symptoms, highlighting the utility of sleep treatment for comorbid disorders experienced by adolescents.

Potential benefits of melatonin to control pain in ventilated preterm newborns: An updated review

Infants admitted to neonatal intensive care units are repeatedly stimulated by painful events, especially if intubated. Preterm infants are known to have greater pain perception than full term infants due to immaturity of descending inhibitory circuits and poor noxious inhibitory modulation. Newborns exposed to repetitive painful stimuli are at high risk of impairments in brain development and cognition. Chronic pain is induced and supported by proinflammatory cytokines, free radicals, and reactive oxygen species creating a self- sustaining vicious circle. Melatonin is a neurohormone secreted by the pineal gland with antioxidant and anti-inflammatory functions. This review describes the in-depth beneficial effects of melatonin for pain control in ventilated preterm newborns. As yet, a minimal amount of literature has been undertaken to consider all its promising bioactivities. The rationale behind the use of melatonin for pain control has also been taken into account in this review. Besides, this review addresses safety concerns and dosages. The potential benefits of melatonin have been assessed against neurological disorders, respiratory distress, microbial infections, and as analgesic adjuvant during ventilation. Additionally, a possible approach for the use of melatonin in ventilated newborns will be discussed.

Practice Tools for Screening and Monitoring Insomnia in Children and Adolescents with Autism Spectrum Disorder

Between 50-80% of children with autism spectrum disorder (ASD) have insomnia, which adversely affects their mental and physical health. However, there is no consensus to-date on suitable tools for insomnia screening and monitoring in daily clinical practice. An expert panel of child neuropsychiatry and sleep specialists, with expertise in children with neurodevelopmental disabilities, recommends: (1) performing insomnia screening of all children with ASD; (2) considering discussion or referral to a sleep specialist when comorbid sleep disorders are suspected. The panel further developed structured, brief screening and monitoring tools to facilitate insomnia screening and management in daily practice, monitor treatment effectiveness and standardize and compare outcomes across clinical settings to improve care and well-being of children with ASD and their families.

Pediatric prolonged-release melatonin for insomnia in children and adolescents with autism spectrum disorders

Introduction: Insomnia is common among children and adolescents with Autism spectrum disorder (ASD). The first drug licensed for insomnia in this population, a pediatric-appropriate prolonged-release melatonin (PedPRM) formulation is described.Areas covered: Literature search on  PedPRM efficacy and safety profile in clinical trials, and a proposed decision-making algorithm to optimize outcome  in the treatment of insomnia in children and adolescents with ASD.Expert opinion: PedPRM treatment effectively improves sleep onset, duration and consolidation, and daytime externalizing behaviors in children and adolescents with ASD and subsequently caregivers' quality of life and satisfaction with their children's sleep. The coated, odorless and taste-free mini-tablets are well-accepted in this population who often have sensory hypersensitivity and problems swallowing standard tablet preparations. The most frequent long-term treatment-related adverse events were fatigue (6.3%), somnolence (6.3%), and mood swings (4.2%) with no evidence of delay in height, BMI, or pubertal development, or withdrawal effects. The starting dose is 2 mg once daily independent of age or weight, escalated to 5-10 mg/day if predefined treatment success criteria are unmet. Slow melatonin metabolizers (~10% of children), may require lower doses. Given its long-term efficacy, safety and acceptance, PedPRM may ameliorate long-term consequences of insomnia in this population.

Melatonin Inhibits Osteoclastogenesis and Bone Loss in Ovariectomized Mice by Regulating PRMT1-Mediated Signaling

Melatonin, a pineal gland hormone, has been suggested to treat postmenopausal osteoporosis due to its inhibitory effect on osteoclast differentiation. We previously reported that protein arginine methyltransferase 1 (PRMT1) was an important mediator of receptor activator of nuclear factor-κB ligand (RANKL)-induced osteoclastogenesis. However, the relationship between melatonin and PRMT1 in osteoclast differentiation and estrogen deficiency-induced osteoporosis is unclear. In this study, we investigated the inhibitory mechanisms of melatonin in vitro and in vivo by focusing on PRMT1. Melatonin treatment effectively blocked RANKL-induced osteoclastogenesis by inhibiting PRMT1 and asymmetric dimethylarginine (ADMA) expression. RANKL-induced tumor necrosis factor receptor-associated factor 6 (TRAF6) and the phosphorylation of JNK were also suppressed by melatonin, and TRAF6 siRNA attenuated RANKL-induced p-JNK and PRMT1 production. Melatonin inhibited the transcriptional activity of NF-κB by interfering with the binding of PRMT1 and NF-κB subunit p65 in RANKL-treated bone marrow-derived macrophages. Our results also revealed that melatonin inhibits RANKL-induced PRMT1 expression through receptors-independent pathway. Thus, the anti-osteoclastogenic effect of melatonin was mediated by a cascade of inhibition of RANKL-induced TRAF6, JNK, PRMT1, and NF-κB signaling in melatonin receptors-independent pathway. In vivo, ovariectomy caused significant decreases in bone mineral density, but melatonin treatment alleviated the ovariectomized (OVX)-induced bone loss by inhibiting bone resorption. Furthermore, the expression PRMT1 and TRAP mRNA was upregulated in OVX-femurs, but effectively suppressed by melatonin injection. These findings suggest that melatonin inhibited osteoclast differentiation and estrogen deficiency-induced osteoporosis by suppressing RANKL-induced TRAF6, JNK, PRMT1, and NF-κB signaling cascades in melatonin receptors-independent pathway.

Use of Nutraceutical Ingredient Combinations in the Management of Tension-Type Headaches with or without Sleep Disorders

Headache is the most common pain complaint in the pediatric population, with tension type headache (TTH) having a prevalence of 10–15% in children. Up to 70% of pediatric patients with chronic headache also experience sleep disruption, with a likely bidirectional relationship between headache and poor sleep. Treatment options include specific pharmacological approaches as well as non-pharmacological alternatives; nutraceuticals have the advantage of a relative lack of side effects. Exogenous melatonin has been shown to be useful and safe in improving sleep-wake cycles and quality of sleep in children, helping to regulate the circadian rhythm, with a secondary positive impact on headache. Supplementation with other nutraceutical ingredients, such as tryptophan, magnesium, and B vitamins, can have significant additional effects in children with primary headache, with or without sleep disorders. Tryptophan may reduce night awakenings and improve the efficiency of sleep. Primary headache has been related to low amounts of magnesium in serum, and integration with magnesium appears to be effective in reducing headache attacks without adverse effects. There are different observational reports and uncontrolled studies suggesting a possible synergistic effect for these nutraceuticals, but there is now a need for high-quality randomized controlled trials in order to confirm these positive preliminary findings.

Chronobiotic effect of melatonin in experimental optic neuritis

Optic neuritis (ON) is an inflammatory condition of the optic nerve, which leads to retinal ganglion cell (RGC) loss. A subset of RGCs expressing the photopigment melanopsin regulates non-image-forming visual system (NIFVS) functions such as pupillary light reflex (PLR) and circadian rhythms. Melatonin is a chronobiotic agent able to regulate the circadian system. We analyzed the effect of ON on the NIFVS, and the effect of melatonin on the NIFVS alterations induced by ON. For this purpose, optic nerves from male Wistar rats received vehicle or bacterial lipopolysaccharide (LPS), and one group of animals received a subcutaneous pellet of melatonin or a sham procedure. The NIFVS was analyzed in terms of: i) blue light-evoked PLR, ii) the communication between the retina and the suprachiasmatic nuclei (by anterograde transport, and ex vivo magnetic resonance images), iii) locomotor activity rhythm, and iv) Brn3a(+) and melanopsin(+) RGC number (by immunohistochemistry). Experimental ON significantly decreased the blue light-evoked PLR, induced a misconnection between the retina and the suprachiasmatic nuclei, decreased Brn3a(+) RGCs, but not melanopsin(+) RGC number. A bilateral injection of LPS significantly increased the light (but not dark) phase locomotor activity, rhythm periodicity, and time of offset activity. Melatonin prevented the decrease in blue light-evoked PLR, and locomotor activity rhythm alterations induced by ON. These results support that ON provoked alterations of the circadian physiology, and that melatonin could restore the circadian system misalignment.

Pediatric Prolonged-Release Melatonin for Sleep in Children with Autism Spectrum Disorder: Impact on Child Behavior and Caregiver's Quality of Life

A randomized, 13-weeks, placebo-controlled double-blind study in 125 subjects aged 2-17.5 years with Autism Spectrum Disorder or Smith-Magenis syndrome and insomnia demonstrated efficacy and safety of easily-swallowed prolonged-release melatonin mini-tablets (PedPRM; 2-5 mg) in improving sleep duration and onset. Treatment effects on child behavior and caregiver's quality of life were evaluated. PedPRM treatment resulted in significant improvement in externalizing but not internalizing behavior (Strengths and Difficulties questionnaire; SDQ) compared to placebo (p = 0.021) with clinically-relevant improvements in 53.7% of PedPRM-treated versus 27.6% of placebo-treated subjects (p = 0.008). Caregivers' quality of life also improved with PedPRM versus placebo (p = 0.010) and correlated with the change in total SDQ (p = 0.0005). PedPRM alleviates insomnia-related difficulties, particularly externalizing behavior in the children, subsequently improving caregivers' quality of life.

The potential utility of melatonin in the treatment of childhood cancer

Childhood cancer management has improved considerably, with the overall objective of preventing early-life cancers completely. However, cancer remains a major cause of death in children, with the survivors developing anticancer treatment-specific health problems. Therefore, the anticancer treatment needs further improvement. Melatonin is a effective antioxidant and circadian pacemaker. Through multiple mechanisms, melatonin has significant positive effects on multitude adult cancers by increasing survival and treatment response rates, and slowing disease progression. In addition, melatonin appears to be safe for children. As an appealing therapeutic agent, we herein address several key concerns regarding melatonin's potential for treating children with cancer.

Effects of melatonin in children with attention-deficit/hyperactivity disorder with sleep disorders after methylphenidate treatment

PURPOSE

Methylphenidate (MPH), the first-line medication in children with attention-deficit/hyperactivity disorder (ADHD), is associated with increased risk of sleep disorders. Melatonin has both hypnotic and chronobiotic properties that influence circadian rhythm sleep disorders. This study explores the effectiveness of melatonin in children with ADHD who developed sleep problems after starting MPH.

PATIENTS AND METHODS

This study, based on a clinical database, included 74 children (69 males, mean age 11.6±2.2 years) naturalistically treated with MPH (mean dosage 33.5±13.5 mg/d). The severity of sleep disorder (sleep onset delay) was recorded at baseline and after a follow-up of at least 4 weeks using a seven-point Likert scale according to the Clinical Global Impression Severity score. Effectiveness of melatonin on sleep (mean dosage 1.85±0.84 mg/d) after 4 weeks was assessed using a seven-point Likert scale according to the Clinical Global Impression Improvement (CGI-I) score, and patients who scored 1 (very much improved) or 2 (much improved) were considered responders.

RESULTS

Clinical severity of sleep disorders was 3.41±0.70 at the baseline and 2.13±1.05 after the follow-up (P<0.001). According to the CGI-I score, 45 patients (60.8%) responded to the treatment with melatonin. Gender and age (children younger and older than 12 years) did not affect the response to melatonin on sleep. Patients with or without comorbidities did not differ according to sleep response. Specific comorbidities with disruptive behavior disorders (oppositional defiant disorder or conduct disorder), affective (mood and anxiety) disorders and learning disabilities did not affect the efficacy of melatonin on sleep. Treatment was well tolerated, and no side effects related to melatonin were reported.

CONCLUSION

In children with ADHD with sleep problems after receiving MPH treatment, melatonin may be an effective and safe treatment, irrespective of gender, age and comorbidities.

Melatonin in the management of perinatal hypoxic-ischemic encephalopathy: light at the end of the tunnel?

Perinatal hypoxic-ischemic encephalopathy (HIE) affects one to three per 1,000 live full-term births and can lead to severe and permanent neuropsychological sequelae, such as cerebral palsy, epilepsy, mental retardation, and visual motor or visual perceptive dysfunction. Melatonin has begun to be contemplated as a good choice in order to diminish the neurological sequelae from hypoxic-ischemic brain injury. Melatonin emerges as a very interesting medication, because of its capacity to cross all physiological barriers extending to subcellular compartments and its safety and effectiveness. The purpose of this commentary is to detail the evidence on the use of melatonin as a neuroprotection agent. The pharmacologic aspects of the drug as well as its potential neuroprotective characteristics in human and animal studies are described in this study. Melatonin seems to be safe and beneficial in protecting neonatal brains from perinatal HIE. Larger randomized controlled trials in humans are required, to implement a long-awaited feasible treatment in order to avoid the dreaded sequelae of HIE.

Dissolution of Intact, Divided and Crushed Circadin Tablets: Prolonged vs. Immediate Release of Melatonin

Circadin 2 mg prolonged-release tablet is the only licensed melatonin product available in the UK. Circadin is indicated for patients with primary insomnia aged 55 and over, but is more widely used "off-label" to treat sleep disorders especially in the paediatric population. Children and older people often have difficulty swallowing tablets and dividing the tablet is sometimes required to ease administration. The aim of this study was to measure the release profile of melatonin from Circadin tablets when divided or crushed, and compare this with release from intact tablets. Dissolution testing was also performed for unlicensed melatonin products for comparison. Dissolution tests were performed using the pharmacopoeial paddle apparatus, with melatonin release analyzed by high performance liquid chromatography. Melatonin content, hardness, friability, and disintegration of the products were also evaluated. The prolonged release of melatonin from Circadin tablets was unlike that of any other product tested. When divided into halves, Circadin preserved most of the prolonged-release characteristic (f2 = 58), whereas quarter-cut and crushed tablet had a more immediate melatonin release profile. Circadin is significantly less expensive and should be preferred to unlicensed medicines which are not pharmaceutically equivalent and offer less quality assurance.

Current role of melatonin in pediatric neurology: clinical recommendations

BACKGROUND/PURPOSE

Melatonin, an indoleamine secreted by the pineal gland, plays a key role in regulating circadian rhythm. It has chronobiotic, antioxidant, anti-inflammatory and free radical scavenging properties.

METHODS

A conference in Rome in 2014 aimed to establish consensus on the roles of melatonin in children and on treatment guidelines.

RESULTS AND CONCLUSION

The best evidence for efficacy is in sleep onset insomnia and delayed sleep phase syndrome. It is most effective when administered 3-5 h before physiological dim light melatonin onset. There is no evidence that extended-release melatonin confers advantage over immediate release. Many children with developmental disorders, such as autism spectrum disorder, attention-deficit/hyperactivity disorder and intellectual disability have sleep disturbance and can benefit from melatonin treatment. Melatonin decreases sleep onset latency and increases total sleep time but does not decrease night awakenings. Decreased CYP 1A2 activity, genetically determined or from concomitant medication, can slow metabolism, with loss of variation in melatonin level and loss of effect. Decreasing the dose can remedy this. Animal work and limited human data suggest that melatonin does not exacerbate seizures and might decrease them. Melatonin has been used successfully in treating headache. Animal work has confirmed a neuroprotective effect of melatonin, suggesting a role in minimising neuronal damage from birth asphyxia; results from human studies are awaited. Melatonin can also be of value in the performance of sleep EEGs and as sedation for brainstem auditory evoked potential assessments. No serious adverse effects of melatonin in humans have been identified.

Analgesic, anxiolytic and anaesthetic effects of melatonin: new potential uses in pediatrics

Exogenous melatonin is used in a number of situations, first and foremost in the treatment of sleep disorders and jet leg. However, the hypnotic, antinociceptive, and anticonvulsant properties of melatonin endow this neurohormone with the profile of a drug that modulates effects of anesthetic agents, supporting its potential use at different stages during anesthetic procedures, in both adults and children. In light of these properties, melatonin has been administered to children undergoing diagnostic procedures requiring sedation or general anesthesia, such as magnetic resonance imaging, auditory brainstem response tests and electroencephalogram. Controversial data support the use of melatonin as anxiolytic and antinociceptive agents in pediatric patients undergoing surgery. The aim of this review was to evaluate available evidence relating to efficacy and safety of melatonin as an analgesic and as a sedative agent in children. Melatonin and its analogs may have a role in antinociceptive therapies and as an alternative to midazolam in premedication of adults and children, although its effectiveness is still controversial and available data are clearly incomplete.

Does melatonin affect epileptic seizures?

Melatonin is widely used for sleep disorders in patients with a range of developmental disorders and neurodisabilities, who also frequently have epilepsy. The aim of our review was to examine published data to assess the evidence for melatonin affecting seizure control. The literature search revealed 26 papers apparently reporting an association between melatonin and epilepsy or seizures but seven of these did not provide relevant information. Of the three double-blind, randomised, controlled trials, two showed no overall worsening or improvement in seizures, and one recent trial reported a statistically significant reduction in seizures. The open studies reported conflicting results. The few studies on the effect of seizures on melatonin levels have reported that baseline melatonin levels may be low in patients with uncontrolled epilepsy and that levels increase markedly following seizures. The striking finding of this review is the paucity of relevant data from the remarkably small number of studies. These results allow no firm conclusions to be drawn, although it would seem reasonable to observe that there was no marked overall effect on seizures, neither improvement nor worsening. There is a need for large, well designed, randomised, double-blind, placebo-controlled trials to establish the role of melatonin in either predisposing to or decreasing the likelihood of seizures.

Roles of melatonin in fetal programming in compromised pregnancies

Compromised pregnancies such as those associated with gestational diabetes mellitus, intrauterine growth retardation, preeclampsia, maternal undernutrition, and maternal stress may negatively affect fetal development. Such pregnancies may induce oxidative stress to the fetus and alter fetal development through the epigenetic process that may affect development at a later stage. Melatonin is an oxidant scavenger that reverses oxidative stress during the prenatal period. Moreover, the role of melatonin in epigenetic modifications in the field of developmental programming has been studied extensively. Here, we describe the physiological function of melatonin in pregnancy and discuss the roles of melatonin in fetal programming in compromised pregnancies, focusing on its involvement in redox and epigenetic mechanisms.

Management of anxiety and sleep disorders: role of complementary and alternative medicine and challenges of integration with conventional orthodox care

There is renewed attention and greater focus on anxiety and sleep- sleep-related disturbances because of the high prevalence, complexity, and their health related implications. The role of complementary and alternative medicine (CAM), which refers to therapeutic approaches that are "complementary to the end goals of decreasing illness and enhancing wellness, but are alternative to conventional medical treatment" is also increasingly recognized. In this review, we considered CAM approach to the management of anxiety and sleep disorders and discussed a few challenges associated with the effective integration of alternative therapy with conventional orthodox medical care.

Melatonin does not influence sleep deprivation electroencephalogram recordings in children

The electroencephalogram (EEG) is an essential diagnostic tool in children with epilepsy. The recording of a sleep EEG can increase the yield of EEG recordings in certain epileptic syndromes. The primary aim of this study was to assess the influence of melatonin on EEG recording (quality, EEG characteristics) and to assess its efficacy to induce sleep. Children with epilepsy or non-epileptic neurological patients requiring sleep deprivation EEG studies were enrolled into this prospective study at a tertiary University Hospital study. Sequential recording of sleep deprivation EEGs both with and without prior administration of melatonin was performed. A total of 50 patients (27 with epilepsy, 23 non-epileptic neurological patients) were included in this study (median age 9.5 years; range 1-18 years; male 28). The quality and EEG characteristics (abnormal findings, depth of sleep) were not affected by the use of melatonin. In total, 92 of 100 EEGs were successfully performed without significant differences between the two groups (six failures with melatonin, two failures without melatonin; p = 0.289).

CONCLUSIONS

We conclude that melatonin does not alter the quality of sleep EEG studies in children with epilepsy or suspected epilepsy. Melatonin does not increase the rate of successfully performed EEG studies in sleep-deprived children.

Melatonin utility in neonates and children

Melatonin (N-acetyl-5-methoxytryptamine) is an endogenously produced indoleamine secreted by the pineal gland and the secretion is suppressed by light. Melatonin is a highly effective antioxidant, free radical scavenger, and has anti-inflammatory effect. Plenty of evidence supports the utility of melatonin in adults for cancer, neurodegenerative disorders, and aging. In children and neonates, melatonin has been used widely, including for respiratory distress syndrome, bronchopulmonary dysplasia, periventricular leukomalacia (PVL), hypoxia-ischemia encephalopathy and sepsis. In addition, melatonin can be used in childhood sleep and seizure disorders, and in neonates and children receiving surgery. This review article discusses the utility of melatonin in neonates and children.

Melatonin in experimental seizures and epilepsy

Although melatonin is approved only for the treatment of jet-lag syndrome and some types of insomnia, clinical data suggest that it is effective in the adjunctive therapy of osteoporosis, cataract, sepsis, neurodegenerative diseases, hypertension, and even cancer. Melatonin also modulates the electrical activity of neurons by reducing glutamatergic and enhancing GABA-ergic neurotransmission. The indoleamine may also be metabolized to kynurenic acid, an endogenous anticonvulsant. Finally, the hormone and its metabolites act as free radical scavengers and antioxidants. The vast majority of experimental data indicates anticonvulsant properties of the hormone. Melatonin inhibited audiogenic and electrical seizures, as well as reduced convulsions induced by pentetrazole, pilocarpine, L-cysteine and kainate. Only a few studies have shown direct or indirect proconvulsant effects of melatonin. For instance, melatonin enhanced low Mg2+-induced epileptiform activity in the hippocampus, whereas melatonin antagonists delayed the onset of pilocarpine-induced seizures. However, the relatively high doses of melatonin required to inhibit experimental seizures can induce some undesired effects (e.g., cognitive and motor impairment and decreased body temperature). In humans, melatonin may attenuate seizures, and it is most effective in the treatment of juvenile intractable epilepsy. Its additional benefits include improved physical, emotional, cognitive, and social functions. On the other hand, melatonin has been shown to induce electroencephalographic abnormalities in patients with temporal lobe epilepsy and increase seizure activity in neurologically disabled children. The hormone showed very low toxicity in clinical practice. The reported adverse effects (nightmares, hypotension, and sleep disorders) were rare and mild. However, more placebo-controlled, double-blind randomized clinical trials are needed to establish the usefulness of melatonin in the adjunctive treatment of epilepsy.

Melatonin versus placebo in children with autism spectrum conditions and severe sleep problems not amenable to behaviour management strategies: a randomised controlled crossover trial

Twenty-two children with autism spectrum disorders who had not responded to supported behaviour management strategies for severe dysomnias entered a double blind, randomised, controlled crossover trial involving 3 months of placebo versus 3 months of melatonin to a maximum dose of 10 mg. 17 children completed the study. There were no significant differences between sleep variables at baseline. Melatonin significantly improved sleep latency (by an average of 47 min) and total sleep (by an average of 52 min) compared to placebo, but not number of night wakenings. The side effect profile was low and not significantly different between the two arms.

Protective effects of melatonin and octreotide against radiation-induced intestinal injury

PURPOSE

To compare the protective effects of the potent antioxidants, melatonin and octreotide, against radiation-induced intestinal injury.

METHODS

A total of 42 male 3-month-old Swiss albino mice (40 ± 10 g) were matched according to body weight and randomly assigned to one of six groups: control; radiation treatment (RT) only; melatonin only (15 mg/kg, i.p.); melatonin + RT; octreotide only (50 μg/kg i.p.); and octreotide + RT. Intestinal damage was induced by exposure to a single whole-body radiation dose of 8 Gy. All mice tolerated the experimental interventions, and no deaths were observed.

RESULTS

Irradiation induced architectural disorganization, including inflammatory mononuclear cell infiltration, villitis, and desquamation with eosinophilic necrosis, and diminished mucosal thickness, crypt height, and villous height. In the melatonin + RT and octreotide + RT groups, the villous pattern was well preserved; desquamation at villous tips and edema was prominent, but necrosis was absent. The radiation-induced decrease in mucosal thickness was significantly reduced by pretreatment with melatonin (p < 0.001) or octreotide (p = 0.01), although the protective effect was significantly greater for melatonin (p = 0.04). Pretreatment with melatonin also preserved villous height (p = 0.009) and crypt height (p = 0.03); although a similar trend was observed for pre-irradiation octreotide, the differences were not significant.

CONCLUSIONS

Melatonin and octreotide potently protected against radiation-induced intestinal injury in mice, but melatonin was significantly more effective in preserving the histological structure of the intestines, a finding that warrants confirmation in clinical studies.

Melatonin in epilepsy and febrile seizures

A study on melatonin rhythm in children with generalized idiopathic epilepsy and simple fever is presented in this article. A population of 40 children was divided into 4 groups, namely, epilepsy, febrile seizure, and 2 control groups. Salivary melatonin was measured by means of radioimmunoassay. Friedman 2-way analysis of variance (ANOVA) and Wilcoxon tests were employed to assess the existence of melatonin rhythm. Comparison across groups was performed by means of ANOVA and Mann-Whitney tests. Higher melatonin levels were found at night, with a peak at 04:00 h in all groups. Significant diurnal rhythm was also detected for these levels. No significant overall differences between case and control groups were found for melatonin levels, though patients showed lower peak melatonin values than controls at 04:00 h with a significant difference in the febrile seizure group (10.70 vs 19.5 pg/mL respectively; P<.04). Our data support the presence of diurnal rhythm in blood melatonin concentrations in children with epileptic and febrile seizures. Comparison between case and control groups showed lower peak concentrations in the febrile seizure group with respect to healthy controls.

Melatonin and sleep-related problems in children with intractable epilepsy

Children with epilepsy have high rates of sleep problems. Melatonin has been advocated in treatment of sleep disorders, and its beneficial effect has been confirmed in insomnia. The aim of this study was to assess melatonin levels in children with intractable epilepsy and its relation to pattern of sleep and characteristics of seizure disorder, as well as the effect of melatonin therapy on those parameters. The study was conducted on 23 children with intractable epilepsy and 14 children with controlled seizures. Patients were evaluated by psychometric sleep assessment and assay of diurnal and nocturnal melatonin levels. Children with intractable epilepsy received oral melatonin before bedtime. They were reassessed after 3 months. Children with intractable epilepsy had higher scores for each category of sleep walking, forcible teeth grinding, and sleep apnea. At the end of therapeutic trial, patients with intractable epilepsy exhibited significant improvement in bedtime resistance, sleep duration, sleep latency, frequent nocturnal arousals, sleep walking, excessive daytime sleepiness, nocturnal enuresis, forcible teeth grinding, sleep apnea, and Epworth sleepiness scores. There was also significant reduction in seizure severity. Thus, use of melatonin in patients with intractable seizures was associated with improvement of both many sleep-related phenomena and the severity of seizures.

The Role of Sleep in Childhood Psychiatric Disorders

Although sleep problems often comprise core features of psychiatric disorders, inadequate attention has been paid to the complex, reciprocal relationships involved in the early regulation of sleep, emotion, and behavior. In this paper, we review the pediatric literature examining sleep in children with primary psychiatric disorders as well as evidence for the role of early sleep problems as a risk factor for the development of psychopathology. Based on these cumulative data, possible mechanisms and implications of early sleep disruption are considered. Finally, assessment recommendations for mental health clinicians working with children and adolescents are provided toward reducing the risk of and improving treatments for sleep disorders and psychopathology in children and adolescents.

Use of Melatonin in Children and Adolescents: Clinicians' and Parents' Perspective

BACKGROUND

  There is a paucity of research on professionals' and parents' views on melatonin use in children and adolescents with sleep problems.

METHOD

  A two-stage survey was employed. First stage: Child psychiatrists and community paediatricians working in a health district were surveyed. Second stage: Parents/carers of children currently on melatonin under the care of these clinicians completed questionnaires.

RESULTS

  Eighty-seven per cent of the participating clinicians prescribed melatonin, with most of them prescribing melatonin for chronic and treatment resistant cases. Differences in prescribing practices between child psychiatrists and community paediatricians were noted. All children were prescribed either 3 mgs or 6 mgs melatonin. None of them experienced any significant side effects.

CONCLUSIONS

  This research highlights that clinicians recognise melatonin as an effective treatment of childhood insomnia and parents value its usefulness too.

Potential pharmacokinetic basis for zolpidem dosing in children with sleep difficulties

The pharmacokinetics of zolpidem was assessed in this open-label, dose-escalation study in children with insomnia. Twenty-one children, seven per age group (2-6, >6 to 12, >12 to 18 years), received a single dose of zolpidem at one of the three dose levels (0.125, 0.25, or 0.50 mg/kg (20 mg maximum dose)). Multiple pharmacokinetic measures were assessed at nine post-dose intervals and pharmacodynamics was assessed by polysomnography and actigraphy. Significant pharmacokinetic effects by dose were observed only as linear increases in maximum concentration (C(max), P<0.001) and area under the plasma concentration-time curve (AUC, P<0.001). Significant pharmacokinetic effects by age group included an increase in AUC (P=0.02), half-life (P=0.04), and mean residence time (P=0.01), whereas total body clearance decreased (P=0.01) and steady-state volume of distribution was variable. Pharmacodynamic measures were independent of the pharmacokinetic estimates. Overall, zolpidem was well tolerated and a pediatric dose of 0.25 mg/kg is recommended for future efficacy studies.

Melatonin prevents learning disorders in brain-lesioned newborn mice

Perinatal brain injuries often result in irreversible learning disabilities, which manifest in early childhood. These injuries are chiefly ascribable to marked susceptibility of the immature brain to glutamate-induced excitotoxicity. No treatments are available. One well-characterized model of perinatal brain injuries consists in injecting the glutamate analog ibotenate into the brain of 5-day-old mice. The resulting excitotoxic lesions resemble the hypoxic-ischemic gray-matter lesions seen in full-term and near-term newborns, as well as the white-matter lesions of preterm newborns. We previously reported that these lesions disrupted odor preference conditioning in newborn mice. The aim of this study was to assess the effectiveness of the neuroprotector melatonin in preventing learning disabilities in newborn mice with ibotenate-induced brain injury. In postnatal day (P) 6-P7 pups, we tested psychomotor reflexes, spontaneous preference for maternal odors as an index of memory, ultrasonic vocalization responses to stroking as an index of sensitivity to tactile stimuli, and conditioned preference for an odor previously paired with stroking as an index of learning abilities. Without melatonin, conditioning was abolished, whereas spontaneous odor preference, psychomotor reflexes, and sensitivity to tactile stimuli were normal. Thus, abolition of conditioning was not associated with sensorimotor impairments. Histological analysis confirmed the efficacy of melatonin in reducing white-matter lesions induced by ibotenate. Furthermore, treatment with melatonin protected the ability to develop conditioning. Thus, melatonin, which easily crosses the blood-brain barrier and has been proven safe in children, may be effective in preventing learning disabilities caused by perinatal brain injuries in human preterm infants.

Are there distinctive sleep problems in Angelman syndrome?

Angelman syndrome is a neurogenetic condition characterized by developmental delay, absence of speech, motor impairment, epilepsy and a peculiar behavioral phenotype that includes sleep problems. It is caused by lack of expression of the UBE3A gene on the maternal chromosome 15q11-q13. Although part of the diagnostic description, 'sleep problems' are not well characterized. A pattern emerges from the available reports. It includes reduced total sleep time, increased sleep onset latency, disrupted sleep architecture with frequent nocturnal awakenings, reduced rapid eye movement (REM) sleep and periodic leg movements. Poor sleep does not significantly interfere with daytime alertness and sleep problems commonly diminish by late childhood, with continuing improvement through adolescence and adulthood. Sleep problems in Angelman syndrome reflect abnormal neurodevelopmental functioning presumably involving dysregulation of GABA-mediated inhibitory influences in thalamocortical interactions. Management may be difficult, particularly in young children; it primarily involves behavioral approaches, though pharmacological treatment may be required. The relationship between sleep and seizure disorder, and between sleep and learning raises critical questions, but more studies are needed to address these relationships adequately.

Melatonin: therapeutic and clinical utilization

Melatonin, acting through melatonin receptors, is involved in numerous physiological processes including circadian entrainment, blood pressure regulation, oncogenesis, retinal physiology, seasonal reproduction, ovarian physiology, immune function and most recently in inducing osteoblast differentiation. Moreover, melatonin was proved to be a potent-free radical scavenger and a broad-spectrum antioxidant. More research is required into the effects of therapeutically modulating the melatoninergic system on circadian haemodynamics and rhythm under varying physiopathological conditions and the possible impact on morbidity and mortality in humans.

Melatonin rhythm in children with enuresis

OBJECTIVE

To study the circadian rhythm of melatonin in children with enuresis.

PATIENTS AND METHODS

Twenty-five children, divided into two groups (enuretic patients and controls) were assessed; salivary samples were collected to measure melatonin by radioimmunoassay using commercial kits. Friedman two-way anova and Wilcoxon tests were used to assess the circadian rhythm of melatonin, and anova with between-patient factors and Mann-Whitney tests to compare melatonin values and groups.

RESULTS

Both groups had statistically significant differences in melatonin concentration during the 24-h period (both P < 0.001), with a circadian rhythm; the highest values were always at approximately 04.00 hours. There were no significant differences overall in melatonin values between cases and controls, but patients had lower peak values than controls at 04.00 hours, and higher melatonin levels at 24.00 hours, but with no significant differences.

CONCLUSION

There was some evidence for minor disturbances in the circadian rhythm of melatonin as a cause of enuresis, but the rhythm was not grossly disrupted.

The effect of melatonin on sedation of children undergoing magnetic resonance imaging

BACKGROUND

Melatonin may induce a natural sleepiness and improve predictability of sedation drugs. We have investigated its clinical value in children sedated for magnetic resonance imaging.

METHODS

In a stratified randomized double-blind study, 98 children received either melatonin or placebo 10 min before they were sedated with a standard oral regimen. Children >5 and <15 kg received chloral hydrate and those >or=15 and <40 kg had a combination of temazepam with droperidol (T&D). The doses of melatonin were 3 and 6 mg, respectively. One observer recorded the time taken to reach criteria for deep sedation, sedation failure and other sedation-related events.

RESULTS

In the chloral hydrate group (n=50) 50% were deeply sedated by 31 min after melatonin and 40 min after placebo (P=0.57). There were zero and 1 failures, respectively. The geometric mean time taken to reach deep sedation was 39 min in both subgroups. In the T&D group (n=48) 50% were deeply sedated by 70 min in both subgroups (two failures in each); geometric mean times were 68 and 71 min, respectively (P=0.58). Children closed their eyes slightly earlier after melatonin (respective geometric means 42 vs 48, P=0.17), and took slightly longer to achieve discharge criteria (146 vs 135, P=0.47).

CONCLUSION

In these doses and clinical conditions, melatonin did not contribute to sedation of children.

Pineal attrition, loss of cognitive plasticity, and onset of puberty during the teen years: is it a modern maladaptation exposed by evolutionary displacement?

Cognitive plasticity, a developmental trait that promotes acquisition of complex skills such as language or playing musical instruments, diminishes substantially during puberty. The loss of plasticity has been attributed to surge of sex steroids during adolescence, but the phenomenon remains poorly understood. We hypothesize that pineal involution during puberty may contribute to plasticity decay. The pineal gland produces melatonin, the level of which declines dramatically during onset of puberty. Emerging evidence suggest that melatonin may modulate cognitive plasticity, independent of the effects of sex steroids, and low sex steroids and high melatonin may be simultaneously required to maintain cognitive plasticity. Potential mechanisms by which melatonin may modulate plasticity are examined within the sleep and hippocampal long-term potentiation frameworks. Implications for psychiatric conditions that involve sleep disorders and learning dysfunctions such as schizophrenia and autism are discussed, and the potential adaptive roles of postprandial and postcoital sleep are explored. From the Darwinian perspective, development and reproductive maturity may represent distinct phases that require tailored cognitive strategies to maximize fitness. While cognitive flexibility and susceptibility to new skills may be paramount during development, reduced cognitive flexibility and increased cognitive determinism may enable more efficient responses to stimuli during adulthood. Thus, cognitive plasticity and cognitive determinism may represent trade-off adaptations and different dimensions of intelligence. The decline of plasticity and emergence of puberty during the second decade may be relics of prehistoric times when the human lifespan was short and the environment was relatively simple and static. Today, when the environment is more complex and dynamic, and humans are living far longer, the early obsolescence of plasticity during puberty may represent a Darwinian inefficiency exposed by evolutionary displacement. Regulation of plasticity may be a systemic phenomenon, as exemplified by the association of learning disability with allergic conditions, a form of immune plasticity dysfunction. Ramifications for other plastic functions that decline during puberty such as wound healing and hyaline cartilage regeneration are explored. Like the plasticity of immunity and cognition, the plasticity of hyaline cartilage during youth may enable hosts to respond to ecologic opportunities and generate the optimally adapted adult phenotype. Pineal involution may represent a potential target for therapeutic extension or restoration of plasticity after puberty. Extending plasticity may have far-reaching consequences for human evolution.

Sleep in children with psychiatric disorders

Although the exact nature of sleep disturbances present in children with psychiatric disorders has not been studied extensively, it is apparent that children with significant emotional and behavioral problems are more likely to experience sleep difficulties. Children with sleep-related issues that are limited to bedtime can be managed effectively with specific cognitive-behavioral interventions. Children with more pervasive anxiety (eg, PTSD or OCD, mood disorders such as major depression or bipolar disorder, or neurodevelopmental disabilities such as autism) require a more exhaustive evaluation, and most of them also need sleep problems to be managed by sleep professionals using combinations of psychotherapeutic and pharmacologic approaches.

Diurnal actions of melatonin on epileptic activity in hippocampal slices of rats

Since melatonin receptors have been found in the hippocampus of mammals it has been suggested that melatonin can modulate neuronal functions of hippocampal cells. The effect of melatonin (10 nM/l and 1 microM/l) on frequency and amplitude of epileptiform field potentials (EFP) elicited by low Mg(2+) or by bicuculline was tested in the CA1 region of hippocampal slices of rats. In the low Mg(2+) model, melatonin, applied in a near physiological concentration of 10 nM/l, exerts no effect on EFP in slices prepared at night or during the day. In a concentration of 1 microM/l, however, melatonin enhances the frequency of EFP to approximately 140% in slices prepared during the day. This effect was suppressed through simultaneous administration of the melatonin receptor antagonist luzindole (10 microM/l). In contrast, melatonin did not affect epileptic activity in slices prepared at night. Epileptiform discharges elicited by blocking the GABAergic inhibition (bicuculline model) were not affected by melatonin, either during the day or at night. The results indicate that melatonin affects epileptic activity in a diurnal manner and that the action of melatonin is different in relation to the epilepsy model.

[Treatment of insomnia in children: pharmacological aspects]

In the last few years topics related to sleep in children have aroused increased interest. Most hypnotic drugs and sedatives used to treat adult insomnia are not recommended in children. Even so, 56% of pediatricians use medication to treat childhood sleep disorders. We review the different causes of insomnia in children from birth to school age. The various therapeutic options are discussed and the therapeutic methods that have been demonstrated to be most effective in the various types of insomnia. The most frequent hypnotic drugs used in insomnia treatment are benzodiazepines and non-benzodiazepine hypnotics such as imidazopyridine, pyrazolopyrimidine and cyclopyrrolone. Few studies have been published on the use of melatonin in insomnia although several reports suggest that is useful and relatively safe in the treatment of insomnia in school-aged children. In children with insomnia, pediatricians should first of all obtain information about the characteristics of insomnia and the environmental characteristics surrounding the child and his/her family. Once an organic cause has been ruled out, treatment should be based on informing the parents about sleep physiology and on training them in sleep hygiene and the acquisition of sleep habits. When pharmacological treatment is required, it should be carefully selected using the smallest effective doses. Melatonin seems to have a promising future in insomnia treatment in healthy children and in those with neurological disorders.

Melatonin in children and adolescents with insomnia: a retrospective study

Effectiveness and tolerability of melatonin was assessed in 32 children (mean age 9.6 +/- 4.5 years) with chronic sleep initiation and sleep maintenance problems treated naturalistically in a pediatric sleep medicine center. Children received melatonin for an average of 2.1 +/- 2.0 months at a final average dose of 2.0 +/- 1.2 mg administered 1 hour before bedtime. Twenty-nine (90.6%) children exhibited partial improvement to complete resolution of their sleep problems as measured by sleep latency time and number of awakenings reported by parents. Thus, melatonin may be effective, safe, and well tolerated in the treatment of chronic insomnia in children.

Schlafstörungen bei kinder- und jugendpsychiatrischen Erkrankungen

Zusammenfassung: Schlafstörungen als Symptom zahlreicher kinder- und jugendpsychiatrischer Störungsbilder komplizieren häufig den Verlauf und die Behandlung der Grunderkrankung. Organische Störungen wie die Narkolepsie oder das Kleine-Levin-Syndrom können zu differentialdiagnostischen Schwierigkeiten und Fehleinschätzungen führen. Unklar ist, ob spezifische Veränderungen der Schlafarchitektur bereits im Kindes- und Jugendalter bestehen und damit als biologischer Trait-Marker für psychiatrische Erkrankungen zu verstehen sind. Während für das Erwachsenenalter die Bedeutung von Schlafstörungen vor allem für die Entwicklung späterer depressiver Störungen belegt werden konnte, ist derzeit offen, ob es sich bei persistierenden Schlafstörungen im Kindesalter um Vulnerabilitätsmarker für psychiatrische Erkrankungen handelt. In der vorliegenden Literaturübersicht sollen Wechselwirkungen zwischen Schlafstörung und psychischer Störung aufgezeigt und die Bedeutung der Berücksichtigung von Schlafstörungen für Diagnostik und Therapie kinder- und jugendpsychiatrischer Störungsbilder unterstrichen werden.