Endogenous melatonin predicts efficacy of exogenous melatonin in consolidation of fragmented wrist-activity rhythm of adult patients with developmental brain disorders: A double-blind, placebo-controlled, crossover study

Endogenous melatonin and sleep in individuals with Rare Genetic Neurodevelopmental Disorders (RGND): A systematic review

Individuals with Rare Genetic Neurodevelopmental Disorders (RGND) present with significant sleep problems and circadian rhythm abnormalities of uncertain aetiology. Abnormal melatonin secretion may play a role in sleep disturbance in individuals with higher incidence developmental disabilities, however, RGND research is limited. This review compared the melatonin profiles in a range of RGND with that of the general population and considered the impact of any differences on sleep. A systematic search identified 19 studies that met inclusion criteria. Each study was examined to extract data relating to the study design, participant characteristics, objectives, sleep measures and results, and melatonin measures and findings. Studies were evaluated using the BIOCROSS quality appraisal tool. Nine studies focussed on Smith-Magenis syndrome (SMS), the rest included individuals with Angelman (AS), Fragile-X (FXS), Prader-Willi (PWS), septo-optic dysplasia, PAX6/WAGR and Williams (WS) syndromes (N = 349). Individuals with RGND present with a range of sleep problems, particularly dyssomnias. The melatonin profile varied within and between RGND, with low nocturnal melatonin levels commonly reported. Understanding the relationship between specific sleep and melatonin parameters within RGND may help inform sleep intervention.

Circadian melatonin profile in opium and amphetamine dependent patients: A preliminary study

Aim

The aim of this study was to investigate the relationship between opium and amphetamine dependency with the serum melatonin levels in the presence of circadian rhythm sleep disorders (CRSD).

Participants

Forty four male amphetamine-dependent and opium-dependent patients with CRSD and with more than one year substance dependency were enrolled in this study. Control group consisted of twelve healthy male subjects.

Design

The diagnoses of sleep disorders were established by a psychiatrist and were made on the basis of the criteria of ICSD-II using the patients’ sleep logs. Blood samples were drawn every 4 h through an intravenous catheter. Serum melatonin levels were assayed using an enzyme-linked immunosorbent assay (ELISA) kit. Repeated Measures Analysis of variance (ANOVA) was used to assess differences between the melatonin levels at six separate times.

Finding

The serum melatonin levels of the control subjects were significantly higher than both opium-dependent and amphetamine-dependent patients at 24:00, 4:00 and 8:00. The serum melatonin level of the opium-dependent patients were significantly lower than the amphetamine-dependent patients at 24:00 (26.9 ± 11.4 vs. 41 ± 19.4, respectively; p = 0.006) and were significantly higher than the amphetamine-dependent patients at 16:00 (12.7 ± 5.1 vs. 8.9 ± 4.1, respectively; p = 0.011).

Conclusion

This is an evidence of negative effects of substance dependence on circadian cycle of melatonin secretion among opium and amphetamine dependent patients.

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Sleep problems in substance abuse patients may be caused by dysfunction of circadian rhythm.

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High prevalence of circadian rhythm sleep disorders (CRSD) in substance dependent patients, possibly related to abnormal melatonin cycle.

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Circadian rhythm-based interventions could play an important role in the prevention and treatment of substance use disorders.

Melatonin Increases Brown Adipose Tissue Volume and Activity in Patients With Melatonin Deficiency: A Proof-of-Concept Study

Melatonin, a pineal hormone synthesized at night, is critical for the synchronization of circadian and seasonal rhythms, being a key regulator of energy metabolism in many animal species. Although studies in humans are lacking, several reports, mainly on hibernating animals, demonstrated that melatonin supplementation and a short photoperiod increase brown adipose tissue (BAT) mass. The present proof-of-concept study is the first, to our knowledge, to evaluate BAT in patients with melatonin deficiency (radiotherapy or surgical removal of pineal gland) before and after daily melatonin (3 mg) replacement for 3 months. All four studied patients presented increased BAT volume and activity measured by positron emission tomography-MRI. We also found an improvement in total cholesterol and triglyceride blood levels without significant effects on body weight, liver fat, and HDL and LDL levels. Albeit not statistically significant, fasting insulin levels and HOMA of insulin resistance decreased in all four patients. The present results show that oral melatonin replacement increases BAT volume and activity and improves blood lipid levels in patients with melatonin deficiency, suggesting that melatonin is a possible BAT activator. Future studies are warranted because hypomelatoninemia is usually present in aging and appears as a result of light-at-night exposure and/or the use of β-blocker drugs.

Melatonin as a Hormone: New Physiological and Clinical Insights

Melatonin is a ubiquitous molecule present in almost every live being from bacteria to humans. In vertebrates, besides being produced in peripheral tissues and acting as an autocrine and paracrine signal, melatonin is centrally synthetized by a neuroendocrine organ, the pineal gland. Independently of the considered species, pineal hormone melatonin is always produced during the night and its production and secretory episode duration are directly dependent on the length of the night. As its production is tightly linked to the light/dark cycle, melatonin main hormonal systemic integrative action is to coordinate behavioral and physiological adaptations to the environmental geophysical day and season. The circadian signal is dependent on its daily production regularity, on the contrast between day and night concentrations, and on specially developed ways of action. During its daily secretory episode, melatonin coordinates the night adaptive physiology through immediate effects and primes the day adaptive responses through prospective effects that will only appear at daytime, when melatonin is absent. Similarly, the annual history of the daily melatonin secretory episode duration primes the central nervous/endocrine system to the seasons to come. Remarkably, maternal melatonin programs the fetuses' behavior and physiology to cope with the environmental light/dark cycle and season after birth. These unique ways of action turn melatonin into a biological time-domain-acting molecule. The present review focuses on the above considerations, proposes a putative classification of clinical melatonin dysfunctions, and discusses general guidelines to the therapeutic use of melatonin.

Comparison of two types of Actiwatch with polysomnography in older adults with intellectual disability: a pilot study

BACKGROUND

The Actiwatch is increasingly being used to investigate sleep. The aim of this study was to investigate which sensitivity setting of the Actiwatch is most suitable to detect sleep disturbance in older adults with intellectual disability (ID).

METHOD

Two Actiwatch types were compared to polysomnography (PSG) in 10 older adults with mild ID, using a 1-min epoch-to-epoch comparison. Outcome measures were sleep detection percentage, wake detection percentage, and overall accuracy of both Actiwatches, and several sleep parameters.

RESULTS

The high sensitivity setting of the Actiwatch appeared most suitable to detect sleep disturbance in older adults with ID (wake detection percentage = 54.6%, sleep detection percentage = 89.7%). Sleep parameters calculated using the high sensitivity setting corresponded well to PSG outcomes. Outcomes were similar for both Actiwatches.

CONCLUSIONS

We recommend using the high sensitivity setting of the Actiwatch for clinical evaluation of sleep, and for epidemiological research in older adults with ID.

Melatonin profile and its relation to circadian rhythm sleep disorders in Angelman syndrome patients

BACKGROUND

Sleep problems are known to be common in Angelman syndrome (AS), a neurodevelopmental disorder which is associated with an abnormality of chromosome 15q11-q13. However, the circadian aspect of sleep disorders in AS and an effective treatment for the disorder have yet to be established.

METHODS

We elucidated the sleep-wake patterns of AS patients and its relationship to the serum melatonin levels. The serum melatonin levels of 15 AS patients were measured every 4h for one day and the values were compared with those of age-matched controls. We also examined the effectiveness of the oral administration of melatonin on AS patients with circadian rhythm sleep disorders (CRSD).

RESULTS

A total of eight of the 15 AS patients had CRSD (irregular sleep-wake type, n=4; free-running type n=2; delayed sleep phase type, n=2). The nighttime serum melatonin levels of the AS patients were significantly lower than those of the controls at the measured time points during the night. The nocturnal melatonin levels were comparably low both in AS patients with and without CRSD except for the cases with delayed sleep phase type, which showed normal but delayed peak melatonin level. Six out of eight CRSD cases were given a daily dose of 1mg of melatonin between 18:00 and 19:00 regularly for three months. After receiving the treatment, the sleep patterns improved in four cases.

CONCLUSION

This study revealed a high prevalence of CRSD in AS patients, which may be related to abnormal serum melatonin profiles.

Melatonin osteoporosis prevention study (MOPS): a randomized, double-blind, placebo-controlled study examining the effects of melatonin on bone health and quality of life in perimenopausal women

The purpose of this double-blind study was to assess the effects of nightly melatonin supplementation on bone health and quality of life in perimenopausal women. A total of 18 women (ages 45-54) were randomized to receive melatonin (3mg, p.o., n=13) or placebo (n=5) nightly for 6months. Bone density was measured by calcaneal ultrasound. Bone turnover marker (osteocalcin, OC for bone formation and NTX for bone resorption) levels were measured bimonthly in serum. Participants completed Menopause-Specific Quality of Life-Intervention (MENQOL) and Pittsburgh Sleep Quality Index (PSQI) questionnaires before and after treatment. Subjects also kept daily diaries recording menstrual cycling, well-being, and sleep patterns. The results from this study showed no significant change (6-month-baseline) in bone density, NTX, or OC between groups; however, the ratio of NTX:OC trended downward over time toward a ratio of 1:1 in the melatonin group. Melatonin had no effect on vasomotor, psychosocial, or sexual MENQOL domain scores; however, it did improve physical domain scores compared to placebo (mean change melatonin: -0.6 versus placebo: 0.1, P<0.05). Menstrual cycling was reduced in women taking melatonin (mean cycles melatonin: 4.3 versus placebo: 6.5, P<0.05), and days between cycles were longer (mean days melatonin: 51.2 versus placebo: 24.1, P<0.05). No differences in duration of menses occurred between groups. The overall PSQI score and average number of hours slept were similar between groups. These findings show that melatonin supplementation was well tolerated, improved physical symptoms associated with perimenopause, and may restore imbalances in bone remodeling to prevent bone loss. Further investigation is warranted.

Effects of morning melatonin administration on electroencephalographic theta to alpha power ratio in reproductive versus postmenopausal healthy female volunteers

OBJECTIVE

The aim of the present study was to investigate the effect of exogenous morning melatonin administration on the electroencephalogram of reproductive versus postmenopausal women.

METHODS

Twenty-six female, reproductive and postmenopausal healthy volunteers were randomly assigned to receive melatonin or placebo at 9:00 in the morning. Twelve electroencephalographic recording sessions were performed before the intake of melatonin or placebo and at 15, 30, 45, 60, 75, 90, 120, 150, 180, 240, and 300 min. Theta to alpha ratios for every subject, channel and session were mathematically processed to yield the logarithm (base 10) of the spectral (theta power)/(alpha power) ratio for the 12 electroencephalographic sessions, weighted to the baseline ratio (LwRs). The LwRs were compared between melatonin groups (reproductive versus postmenopausal women) and also between melatonin and control groups.

RESULTS

Data from 24 women were analyzed. The LwRs in the reproductive women were significantly lower than the LwRs in postmenopausal women at 60, 180, 240 and 300 min after melatonin consumption (p=0.007, 0.041, 0.008 and 0.040 respectively). In reproductive women, the LwRs of subjects who received melatonin were significantly lower compared to their controls at 60, 240 and 300 min after melatonin or placebo intake (p=0.005, 0.006 and 0.019 respectively). In postmenopausal women, no significant differences in the LwRs were calculated for any time point between melatonin and control groups.

CONCLUSIONS

Our results show that morning melatonin administration produces no electroencephalographic changes in postmenopausal women. In contrast, electroencephalographic changes suggesting a possible awaking effect were observed in reproductive women.

Genetic variations of the melatonin pathway in patients with attention-deficit and hyperactivity disorders

Melatonin is a powerful antioxidant and a synchronizer of many physiological processes. Alteration in melatonin signaling has been reported in a broad range of diseases, but little is known about the genetic variability of this pathway in humans. Here, we sequenced all the genes of the melatonin pathway -AA-NAT, ASMT, MTNR1A, MTNR1B and GPR50 - in 321 individuals from Sweden including 101 patients with attention-deficit/hyperactivity disorder (ADHD) and 220 controls from the general population. We could find several damaging mutations in patients with ADHD, but no significant enrichment compared with the general population. Among these variations, we found a splice site mutation in ASMT (IVS5+2T>C) and one stop mutation in MTNR1A (Y170X) - detected exclusively in patients with ADHD - for which biochemical analyses indicated that they abolish the activity of ASMT and MTNR1A. These genetic and functional results represent the first comprehensive ascertainment of melatonin signaling deficiency in ADHD.

Exogenous melatonin for sleep problems in individuals with intellectual disability: a meta-analysis

Recent meta-analyses on melatonin has raised doubts as to whether melatonin is effective in treating sleep problems in people without intellectual disabilities. This is in contrast to results of several trials on melatonin in treating sleep problems in individuals with intellectual disabilities. To investigate the efficacy of melatonin in treating sleep problems in individuals with intellectual disabilities, we performed a meta-analysis of placebo-controlled randomized trials of melatonin in individuals with intellectual disabilities and sleep problems. Data were selected from articles published on PubMed, Medline, and Embase between January 1990 and July 2008. We examined the influence of melatonin on sleep latency, total sleep time, and number of wakes per night. Quality of trials was assessed using the Downs and Black checklist. Nine studies (including a total of 183 individuals with intellectual disabilities) showed that melatonin treatment decreased sleep latency by a mean of 34 minutes (p<0.001), increased total sleep time by a mean of 50 minutes (p<0.001), and significantly decreased the number of wakes per night (p<0.05). Melatonin decreases sleep latency and number of wakes per night, and increases total sleep time in individuals with intellectual disabilities.