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Some Reflections on Sleep and its Treatment
Alzheimer's disease (AD) is an age-related neurodegenerative disease characterized by progressive memory loss, declining language skills and other cognitive disorders. AD has brought great mental and economic burden to patients, families and society. However due to the complexity of AD's pathology, drugs developed for the treatment of AD often fail in clinical or experimental trials. The main problems of current anti-AD drugs are low efficacy due to mono-target method or side effects, especially high hepatotoxicity. To tackle these two main problems, multi-target-directed ligand (MTDL) based on "one molecule, multiple targets" has been studied. MTDLs can regulate multiple biological targets at the same time, so it has shown higher efficacy, better safety. As a natural active small molecule, α-mangostin (α-M) has shown potential multi-factor anti-AD activities in a series of studies, furthermore it also has a certain hepatoprotective effect. The good availability of α-M also provides support for its application in clinical research. In this work, multiple activities of α-M related to AD therapy were reviewed, which included anti-cholinesterase, anti-amyloid-cascade, anti-inflammation, anti-oxidative stress, low toxicity, hepatoprotective effects and drug formulation. It shows that α-M is a promising candidate for the treatment of AD.
Light-emitting diodes (LEDs) have been used to provide illumination in industrial and commercial environments. LEDs are also used in TVs, computers, smart phones, and tablets. Although the light emitted by most LEDs appears white, LEDs have peak emission in the blue light range (400–490 nm). The accumulating experimental evidence has indicated that exposure to blue light can affect many physiologic functions, and it can be used to treat circadian and sleep dysfunctions. However, blue light can also induce photoreceptor damage. Thus, it is important to consider the spectral output of LED-based light sources to minimize the danger that may be associated with blue light exposure. In this review, we summarize the current knowledge of the effects of blue light on the regulation of physiologic functions and the possible effects of blue light exposure on ocular health.
Orexin A and orexin B are hypothalamic neuropeptides initially identified as endogenous ligands for two orphan G-protein coupled receptors (GPCRs). They play critical roles in the maintenance of wakefulness by regulating function of monoaminergic and cholinergic neurons that are implicated in the regulation of wakefulness. Loss of orexin neurons in humans is associated with narcolepsy, a sleep disorder characterized by excessive daytime sleepiness and cataplexy, further suggesting the particular importance of orexin in the maintenance of the wakefulness state. These findings have encouraged pharmaceutical companies to develop drugs targeting orexin receptors as novel medications of sleep disorders, such as narcolepsy and insomnia. Indeed, phase III clinical trials were completed last year of suvorexant, a non-selective (dual) antagonist for orexin receptors, for the treatment of primary insomnia, and demonstrate promising results. The New Drug Application (NDA) for suvorexant has been submitted to the US FDA. Thus, the discovery of a critical role played by the orexin system in the regulation of sleep/wakefulness has opened the door of a new era for sleep medicine.
Millions of individuals habitually expose themselves to room light in the hours before bedtime, yet the effects of this behavior on melatonin signaling are not well recognized.
We tested the hypothesis that exposure to room light in the late evening suppresses the onset of melatonin synthesis and shortens the duration of melatonin production.
In a retrospective analysis, we compared daily melatonin profiles in individuals living in room light (<200 lux) vs. dim light (<3 lux).
Healthy volunteers (n = 116, 18-30 yr) were recruited from the general population to participate in one of two studies.
Participants lived in a General Clinical Research Center for at least five consecutive days.
Individuals were exposed to room light or dim light in the 8 h preceding bedtime.
Melatonin duration, onset and offset, suppression, and phase angle of entrainment were determined.
Compared with dim light, exposure to room light before bedtime suppressed melatonin, resulting in a later melatonin onset in 99.0% of individuals and shortening melatonin duration by about 90 min. Also, exposure to room light during the usual hours of sleep suppressed melatonin by greater than 50% in most (85%) trials.
These findings indicate that room light exerts a profound suppressive effect on melatonin levels and shortens the body's internal representation of night duration. Hence, chronically exposing oneself to electrical lighting in the late evening disrupts melatonin signaling and could therefore potentially impact sleep, thermoregulation, blood pressure, and glucose homeostasis.
We applied the directional tag PCR subtractive hybridization method to construct a rat hypothalamic cDNA library from which cerebellar and hippocampal sequences had been depleted, enriching 20-30-fold for sequences expressed selectively in the hypothalamus. We studied a sample of 94 clones selected for enrichment in the subtracted library. These clones corresponded to 43 distinct mRNA species, about half of which were novel. Thirty-eight of these 43 mRNAs (corresponding to 85 of the clones in the sample) exhibited enrichment in the hypothalamus; 23 were highly enriched. In situ hybridization studies revealed that one novel species was restricted to cells in a small bilaterally symmetric area of the paraventricular hypothalamus. Other novel mRNAs showed substantial enrichment in basal diencephalic structures, particularly the hypothalamus, without restriction to single hypothalamic nuclei. The data suggest that the hypothalamus utilizes at least two distinct strategies for employing its selectively expressed proteins. Secretory neuropeptides utilized for intercellular communication are produced by functionally discrete nuclei, while several other proteins are shared by structures that are unrelated in their physiological roles but may share biochemical systems.
Murine and canine narcolepsy can be caused by mutations of the hypocretin (Hcrt) (orexin) precursor or Hcrt receptor genes. In contrast to these animal models, most human narcolepsy is not familial, is discordant in identical twins, and has not been linked to mutations of the Hcrt system. Thus, the cause of human narcolepsy remains unknown. Here we show that human narcoleptics have an 85%-95% reduction in the number of Hcrt neurons. Melanin-concentrating hormone (MCH) neurons, which are intermixed with Hcrt cells in the normal brain, are not reduced in number, indicating that cell loss is relatively specific for Hcrt neurons. The presence of gliosis in the hypocretin cell region is consistent with a degenerative process being the cause of the Hcrt cell loss in narcolepsy.
Purpose:
Female veterans are at high risk for sleep problems, and there is a need to provide effective treatment for this population who experience insomnia. This study's primary goal was to compare the acceptability of medication versus nonmedication treatments for insomnia among female veterans. In addition, we examined the role of patient age, severity of sleep disturbance, and psychiatric symptoms on acceptability of each treatment approach and on the differences in acceptability between these approaches.
Methods:
A large nationwide postal survey was sent to a random sample of 4000 female veterans who had received health care at a Veterans Administration (VA) facility in the previous 6 months (May 29, 2012-November 28, 2012). A total of 1559 completed surveys were returned. Survey items used for the current analyses included: demographic characteristics, sleep quality, psychiatric symptoms, military service experience, and acceptability of medication and nonmedication treatments for insomnia. For analysis, only ratings of "very acceptable" were used to indicate an interest in the treatment approach (vs ratings of "not at all acceptable," "a little acceptable," "somewhat acceptable," and "no opinion/don׳t know").
Findings:
In the final sample of 1538 women with complete data, 57.7% rated nonmedication treatment as very acceptable while only 33.5% rated medication treatment as very acceptable. This difference was statistically significant for the group as a whole and when examining subgroups of patients based on age, sleep quality, psychiatric symptoms, and military experience. The percentage of respondents rating medication treatment as very acceptable was higher for women who were younger, had more severe sleep disturbances, had more psychiatric symptoms, who were not combat exposed, and who had experienced military sexual trauma. By contrast, the percentage of respondents rating nonmedication treatment as very acceptable differed only by age (younger women were more likely to find nonmedication treatment acceptable) and difficulty falling asleep.
Implications:
Female veterans are more likely to find nonmedication insomnia treatment acceptable compared with medication treatment. Thus, it is important to match these patients with effective behavioral interventions such as cognitive behavioral therapy for insomnia. Efforts to educate providers about these preferences and about the efficacy of cognitive behavioral therapy for insomnia may serve to connect female veterans who have insomnia to the treatment they prefer. These findings also suggest that older female veterans may be less likely to find either approach as acceptable as their younger counterparts.
Purpose:
Insomnia is problematic for older adults. After behavioral modifications fail to show adequate response, pharmacologic options are used. The pharmacokinetics of agents used to treat insomnia may be altered. This review focuses on the safety and efficacy of medications used to treat insomnia.
Methods:
A literature search of Medline, PubMed, and Embase was conducted (January 1966-June 2016). It included systematic reviews, randomized controlled trials, observational studies, and case series that had an emphasis on insomnia in an older population. Search terms included medications approved by the US Food and Drug Administration for insomnia: benzodiazepines (triazolam, estazolam, temazepam, flurazepam, and quazepam), nonbenzodiazepine receptor agonists (non-BzRAs; zaleplon, zolpidem, and eszopiclone), suvorexant, ramelteon, doxepin and trazodone. Off-label drugs such as other antidepressants, antihistamines, antipsychotics, gabapentin, pramipexole, tiagabine, valerian, and melatonin were also included.
Findings:
Cognitive behavioral therapy and sleep hygiene are considered initial therapy for insomnia. Benzodiazepines are discouraged in the geriatric population, especially for long-term use. Although non-BzRAs have improved safety profiles compared with benzodiazepines, their side effects include dementia, serious injury, and fractures, which should limit their use. Ramelteon has a minimal adverse effect profile and is effective for sleep-onset latency and increased total sleep time, making it a valuable first-line option. Although the data on suvorexant are limited, this drug improves sleep maintenance and has mild adverse effects, including somnolence; residual daytime sedation has been reported, however. Sedating low-dose antidepressants should only be used for insomnia when the patient has comorbid depression. Antipsychotic agents, pramipexole, and tiagabine have all been used for insomnia, but none has been extensively studied in an older population, and all have considerable adverse effects. Gabapentin may be useful in patients with restless leg syndrome or chronic neuropathic pain and insomnia. Diphenhydramine should be avoided in the elderly. Valerian and melatonin are unregulated products that have a small impact on sleep latency and can produce residual sedation.
Implications:
An ideal treatment for insomnia should help to improve sleep latency and sleep duration with limited awakenings and be without significant adverse effects such as daytime somnolence or decreased alertness. Cognitive behavioral therapy should always be first line treatment. Clinical inertia regarding previous prominent use of benzodiazepines and non-BzRAs will be a significant challenge for patients accustomed to their issuance. The future direction of insomnia treatment should have an emphasis on nonpharmacologic interventions, treating comorbid conditions, and focusing therapy on using benzodiazepines and non-BzRAs as last resorts.
Purpose:
Obstructive sleep apnea is a prevalent sleep disorder among older adults. Oral appliances are increasingly prescribed as therapy for obstructive sleep apnea. Adherence to oral appliance therapy is highly variable. Based on value-expectancy theory and other social-psychological theories, adherence to oral appliance therapy may be influenced by patients' perceived effectiveness of the therapy, self-efficacy, and availability of social support. We examined these perceptions among older adults with obstructive sleep apnea who were prescribed oral appliance therapy.
Methods:
We mailed surveys to all patients aged ≥65 years who had been prescribed oral appliance therapy for obstructive sleep apnea over the prior 36 months at a Veterans Affairs medical center. We examined frequencies of responses to items that assessed perceived effectiveness, self-efficacy, and social support for nightly use of oral appliances from friends, family, or health care staff.
Findings:
Thirty-nine individuals responded (response rate, 30%; mean [SD] age 71.4 [SD 6.3] years; 97% male). Thirty-six percent of the respondents perceived regular use of oral appliance therapy to be effective in managing obstructive sleep apnea; 39% agreed that they felt confident about using oral appliances regularly; 41% felt supported by people in their life in using oral appliance therapy; and 38% agreed that health care staff would help them to use their oral appliance regularly. These rates represented less than half of respondents despite the finding that 65% of patients believed that they would use their oral appliance regularly.
Implications:
Although oral appliance therapy is increasingly prescribed for obstructive sleep apnea, only about one third of older adults prescribed it perceived it to be an effective treatment, were confident about oral appliance use, and/or believed that they would receive needed support. Future research is needed to better understand older adults' perceptions so that interventions can be designed to improve the effectiveness of oral appliances, their self-efficacy for using oral appliances, and their social support for this therapy, which may, in turn, improve oral appliance therapy adherence.
Whether as a standalone disorder or as a symptom associated with existing pathology, the prevalence of sleep disturbance increases with age. Older adults also experience a myriad of risk factors for suicide, including depression, and have elevated rates of suicide. There is now significant evidence linking sleep disturbances to suicidal thoughts and behaviors. The use of pharmacologic means to treat insomnia (e.g., sedative hypnotics) is also commonplace among older cohorts and has been associated with suicide. Behavioral treatment of insomnia represents an efficacious alternative to pharmacotherapy among older adults, which while improving sleep, may concurrently reduce depressive symptomatology. Implications and clinical recommendations of the sleep–suicide relationship are discussed.
The 2015 American Geriatrics Society (AGS) Beers Criteria are presented. Like the 2012 AGS Beers Criteria, they include lists of potentially inappropriate medications to be avoided in older adults. New to the criteria are lists of select drugs that should be avoided or have their dose adjusted based on the individual's kidney function and select drug-drug interactions documented to be associated with harms in older adults. The specific aim was to have a 13-member interdisciplinary panel of experts in geriatric care and pharmacotherapy update the 2012 AGS Beers Criteria using a modified Delphi method to systematically review and grade the evidence and reach a consensus on each existing and new criterion. The process followed an evidence-based approach using Institute of Medicine standards. The 2015 AGS Beers Criteria are applicable to all older adults with the exclusion of those in palliative and hospice care. Careful application of the criteria by health professionals, consumers, payors, and health systems should lead to closer monitoring of drug use in older adults.
Animal studies have shown that decreased orexin expression changes sleep regulation with normal aging. This study examined orexin A and B expression in the tuberal hypothalamus in infants (0-1 year; n = 8), children (4-10 years; n = 7), young adults (22-32 years; n = 4), and older (48-60 years; n = 7) adults. Neuronal expression was defined by the percentage positive orexin immunoreactive (Ox-ir) neurons in the whole tuberal hypothalamus, and in the dorsal medial (DMH), perifornical, and lateral hypothalamus. In addition, the number of Ox-ir neurons/mm(2), regional distribution, and co-localization were examined. Within the whole tuberal hypothalamic section, there was a 23% decrease in the percentage of Ox-ir neurons between infants and older adults (p < 0.001), and a 10% decrease in older compared with younger adults (p = 0.023). These changes were confined to the DMH and/or perifornical hypothalamus. There was a 9%-24% decrease in Ox neurons/mm(2) in adults compared with infants and/or children (p ≤ 0.001). These results demonstrate a decrease in Ox expression with normal human maturation and aging. This may contribute to changes in sleep regulation during development and with aging.
Endogenous rhythms of circalunar periodicity (w29.5 days) and their underlying molecular and genetic basis have been demonstrated in a number of marine species [1, 2]. In contrast, there is a great deal of folklore but no consistent association of moon cycles with human physiology and behavior [3]. Here we show that subjective and objective measures of sleep vary according to lunar phase and thus may reflect circalunar rhythmicity in humans. To exclude confounders such as increased light at night or the potential bias in perception regarding a lunar influence on sleep, we retrospectively analyzed sleep structure, electroencephalographic activity during non-rapid-eye-movement (NREM) sleep, and secretion of the hormones melatonin and cortisol found under stringently controlled laboratory conditions in a
cross-sectional setting. At no point during and after the study were volunteers or investigators aware of the a posteriori analysis relative to lunar phase. We found that around full moon, electroencephalogram (EEG) delta activity during NREM sleep, an indicator of deep sleep, decreased by 30%, time to fall asleep increased by 5 min, and EEG-assessed total sleep duration was reduced by 20 min. These changes
were associated with a decrease in subjective sleep quality and diminished endogenous melatonin levels. This is the first reliable evidence that a lunar rhythm can modulate sleep structure in humans when measured under the highly controlled conditions of a circadian laboratory study protocol without time cues.
Aging is associated with many physiological alterations-such as changes in sleep patterns, metabolism and food intake-suggestive of hypothalamic dysfunction, but the effects of senescence on specific hypothalamic nuclei and neuronal groups that mediate these alterations is unclear. The lateral hypothalamus and contiguous perifornical area (LH/PFA) contains several populations of neurons, including those that express the neuropeptides orexin (hypocretin) or melanin-concentrating hormone (MCH). Collectively, orexin and MCH neurons influence many integrative homeostatic processes related to wakefulness and energy balance. Here, we determined the effect of aging on numbers of orexin and MCH neurons in young adult (3-4 months) and old (26-28 months) Fisher 344/Brown Norway F1 hybrid rats. Aged rats exhibited a loss of greater than 40% of orexin-immunoreactive neurons in both the medial and lateral (relative to the fornix) sectors of the LH/PFA. MCH-immunoreactive neurons were also lost in aged rats, primarily in the medial LH/PFA. Neuronal loss in this area was not global as no change in cells immunoreactive for the pan-neuronal marker, NeuN, was observed in aged rats. Combined with other reports of altered receptor expression or behavioral responses to exogenously-administered neuropeptide, these data suggest that compromised orexin (and, perhaps, MCH) function is an important mediator of age-related homeostatic disturbances of hypothalamic origin. The orexin system may represent a crucial substrate linking homeostatic and cognitive dysfunction in aging, as well as a novel therapeutic target for pharmacological or genetic restoration approaches to preventing or ameliorating these disturbances.
Loss of neurons or neuronal functions over time has been hypothesized to contribute to the dysregulation of autonomic functions observed in aging. In this study, we evaluated the total number of the hypothalamic hypocretin (orexin) immunopositive neurons in 100, 400, 800 and 1000-day-old male and female C57Bl/6 mice that are commonly used in aging studies in vertebrates. Males had 15-20% more hypocretin immunopositive neurons (HIN) than females at all ages examined. Neuronal number for both sexes was stable in the first 400 days of life, but started declining between 400 and 800 days with rates of approximately 1 neuron/day. The rate of loss doubled in males between 800 and 1000 days of age. The total average number of HIN for males was 2251+/-139 at 100 days, 2235+/-112 at 400 days, 1914+/-81 at 800 days, and 1596+/-301 at 1000 days. The total average number of HIN for females was 1805+/-76 at 100 days, 1887+/-118 at 400 days, and 1521+/-181 at 800 days. Evaluation of the time-dependent decline in the number of hypocretin immunopositive neurons may help to explain the physiological changes in sleep or energy homeostasis regulation during aging.
This article has no abstract; the first 100 words appear below.
Beginning with chlordiazepoxide in 1960, benzodiazepines have been used extensively for the treatment of anxiety and related disorders. Eight benzodiazepine derivatives have been approved by the Food and Drug Administration for this purpose (Table 1). Another benzodiazepine, clonazepam, is also prescribed for this purpose but is labeled as an anticonvulsant. The clinical, pharmacokinetic, and neurochemical properties of the benzodiazepine derivatives have been the focus of many articles in the scientific literature¹–⁶. Much is known about their molecular mechanisms of action, properties of distribution and elimination, clinical activity, and side effects. Like many other classes of drugs that are . . .
Supported in part by a grant (MH-34223) from the Department of Health and Human Services.
We are indebted to Dr. Lawrence G. Miller and Mr. Jerold S. Harmatz for their ongoing collaboration.
Source Information
From the Department of Pharmacology and Experimental Therapeutics, Tufts University School of Medicine, and the Division of Clinical Pharmacology, New England Medical Center Hospital, Boston.
Address reprint requests to Dr. Shader at the Department of Pharmacology and Experimental Therapeutics, Tufts University School of Medicine, 136 Harrison Ave., Boston, MA 02111.
Prior to three months of age there is little melatonin (MLT) secretion in humans. MLT production then commences, becomes circadian, and reaches its highest nocturnal blood levels between the ages of one to three years. During the remainder of childhood, nocturnal peak levels drop progressively by 80%. In adults, these levels show an additional drop of some 10%, mainly during senescence. The large drop in serum MLT during childhood is probably the result of the increase in size of the human body, despite a constant MLT production after infancy. The additional decline of MLT with higher age may be due to a yet unidentified physiological mechanism accompanying senescence. The biological significance of these MLT alterations remains unknown. Since the discovery of MLT, an immediate sedative action of this hormone has been known. A number of recent studies have demonstrated that MLT indeed exerts a sleep-promoting action by accelerating sleep initiation, improving sleep maintenance, and marginally altering sleep architecture. The potential of MLT in the treatment of insomnia is being explored, and the results are promising. Although in most of these studies pharmacological dosages of MLT have been used, preliminary data suggest that similar effects can also be achieved by physiological hormone concentrations. The latter observation raises the question of whether MLT might be involved in the physiological control of sleep.
Hypocretin-1 (hcrt-1) and hypocretin-2 (hcrt-2) have been implicated in a wide variety of functions including sleep and wakefulness as well as related behaviors. Many of these functions of the hypocretins involve the activation of cholinergic neurons in the basal forebrain (BF). These neurons have been shown to exhibit age-related changes in a variety of species. In the present experiment, in adult and aged guinea pigs, we compared hypocretin immunoreactivity in regions of the BF that include the medial septal nucleus (MS), the vertical and horizontal limbs of the diagonal band of Broca (VDB and HDB) and the magocellular preoptic nucleus (MCPO). In adult guinea pigs (3-5 months of age), all of the preceding BF regions contained dense hypocretin fibers with varicosities. On the contrary, in old guinea pigs (27-28 months), although the MS exhibited a similar intensity of hypocretin immunoreactivity compared with the adult guinea pig, there was a significant decrease in the intensity of immunoreactivity of hypocretinergic fibers in the VDB, HDB and MCPO. These data indicate that the hypocretinergic innervation of specific nuclei of the BF is compromised during the aging process. We suggest that the reduction in hypocretinergic innervation of the BF nuclei may contribute to the age-related changes in the states of sleep and wakefulness as well as deficits in related systems that occur in old age.