Sleep deficiency is pervasive in today’s society and associated with an array of threats to health and public safety. The availability of a biomarker(s) for sleep health would turn-the-curve on developing practical and feasible ways to identify individuals at risk for sleep deficiency and prevent/manage associated risks to health and public safety on a large-scale.

Sleep and circadian regulation is coupled to an array of behavioral, physiological and molecular/genetic processes to leverage in the development of biomarkers for sleep health.
Untreated sleep disorders and sleep deficiency pose a significant burden on health and public safety. There is currently no biomarker, or point-of-care technology available to objectively measure an individual’s level of sleep deficiency or susceptibility, a significant barrier to prevention and management.

Sleep deficiency and untreated sleep disorders threaten the health of 20-30 percent of US adults through an increased risk of stroke, hypertension, diabetes, inflammatory disease, and all-cause mortality. Developing the scientific evidence-base of validated interventions will enhance the management of cardiometabolic and pulmonary risks to health, present new opportunities for secondary prevention, and reduce associated burden on health care systems.

Improving sleep health through informed public recognition of decision-relevant science, and relatively low cost therapies for management of sleep disorders are available for immediate assessment of impact in appropriate clinical trials to demonstrate efficacy and effectiveness.
Discovery research advances implicate an array of cellular sleep and circadian mechanisms in pathophysiological pathways leading to cardiometabolic and pulmonary disease.

Irregular and disturbed sleep impairs cellular biological rhythm in all tissues and organs leading to oxidative stress, unfolded protein responses, and impaired cell function. The pathophysiological findings juxtaposed with epidemiological evidence of disease risk indicate that sleep deficiency contributes to an erosion of health across the lifespan over and above the effects of aging.

Existing assessments based on intensive overnight physiological measurements of sleep interpreted by medical specialists are impractical for the goal of diagnosing a spectrum of sleep-related health risks and the need to protect the safety of the public at large. Sleep/circadian-related biomarker panels are needed to enable the development of practical diagnostic tests for point of care implementation, and determining whether the response to therapy has been successful.

Mature high-throughput genomic technologies combined with recent advances in our knowledge of sleep-coupled pathways provide a rich foundation for systematic investigation and the application of computational modeling strategies.
Discovery research advances implicate an array of cellular sleep and circadian mechanisms in pathophysiological pathways leading to cardiometabolic and pulmonary disease. Irregular and disturbed sleep impairs cellular biological rhythm in all tissues and organs leading to oxidative stress, unfolded protein responses, and impaired cell function. These pathophysiological changes are accessible to existing high-throughput quantitative technologies facilitating systematic study and the identification of candidates and panels of candidate correlating with sleep health status.

A primary focus on principles of psychology may result in significantly improved control of the obesity epidemic. Effective interventions could reduce the risk of diabetes, sleep apnea, and hypertension. This research could also affect clinical practice guidelines for weight loss and obesity treatment.

Psychological science has been successful in developing effective treatments for a number of conditions, including sleep disorders, depressive symptoms, anxiety and phobias. Many of the behavioral principles employed in such interventions (e.g., cognitive restructuring, motivational methods) could be translated for the prevention and treatment of obesity within a reasonable time frame. Additional attention should be directed to the needs of population subgroups in which obesity is most prevalent.
In their Viewpoint article on weight loss intervention research, Pagoto and Appelhans (JAMA, 2013, see attachment) question whether a continued focus on dietary factors in research on weight loss and obesity is warranted. Their commentary raises the importance of attention to the individual psychological characteristics that influence adherence to weight loss interventions rather than dietary composition.

Understanding how lymphatic system contributes to normal physiology of heart, lung, blood, sleep systems will help also lead to new approaches for treatment of heart, lung, blood, sleep diseases.

Basic understanding of the development and hemodynamics of the lymphatic system and reagents to study the lymphatic function are available.
Lymphatic vasculature is essential for fluid hemostasis in the body, collects and returns the protein- and lipid-rich interstitial fluid to blood circulation, and also involved in immune cell trafficking and inflammation. Given these important physiological roles, function of the lymphatic system is expected to contribute to normal physiology of organs and its dysfunction to major diseases. There is very little or no information how the lymphatic system contribute to health and diseases of the cardiovascular, pulmonary and blood systems, and there are many unanswered questions. Answers to these questions may lead to new approaches for treatment of major HLB diseases. Main challenge is to get heart, lung, blood, sleep investigators interested in studying the contribution of the lymphatic system to heart, lung, blood, sleep health and diseases.

By identifying the mechanisms by which sleep loss or disruption affects cognitive, cardiovascular, and metabolic function, we hope to find key regulatory points for which interventions may be developed. For example, if we can allow respiratory reflex responses to reopen the airway without EEG activation during OSA, we may be able to forestall some of the cognitive consequences of inadequate sleep. If we can prevent the autonomic responses associated with the EEG arousals and increases in respiratory drive, we may be able to block the repetiive elevations of blood pressure that lead to long term hypertension and accelerated atherosclerosis. If we can identify the reason for metabolic derangement associated with OSA, we may find, for example, that it is due to circadian misalignment and find ways to realign the sequence of metabolic events with the actual wake-sleep patterns of the patients. Finally, if we can potentiate the respiratory reflexes that re-establish the airway in OSA, without triggering the other components of arousals, we may be able to minimize or prevent the apneas. While current methods for treating OSA (e.g., CPAP and dental appliances) help many people, many others cannot tolerate these devices, and we require additional modes of therapy to mitigate the consequences of OSA.

The methods are currently available to address the questions that are raised above. The revolution in methods for evaluating the functions of neural circuits, using optogenetics and chemogenetics, for example, should allow us to identify brain circuits that are involved in the various components of the reflex responses to apnea. We can examine their neurotransmitters and receptors, and design new therapies based on manipulating CNS circuitry. Methods for assessing ongoing autonomic, respiratory, and metabolic responses in genetically mutated mouse modesl may require further miniaturization of various physiological methods, but this field is also rapidly advancing. Finally, methods for examining ongoing changes in neuronal activity in the living brain of awake mice are rapidly advancing.

Circadian rhythm disorders (delayed sleep phase disorder, non-24-hour sleep-wake disorder, irregular sleep-wake disorder) have been ignored by many sleep researchers. They should not be. First, they reduce lives to rubble: education, employment, partnering, and parenting suffer or are not possible. Second, nocturnals who force themselves to live a diurnal life are at higher risk of disease (as are diurnals who work 3rd shift) and accidents. Third, evidence is mounting that circadian rhythms play a significant role in immunity, cancer, heart disease, diabetes, obesity, metabolic (dys)regulation, mental health, medication administration, and public health (think of the spike in accidents after spring and fall time changes).

To date, most circadian research has been conducted on "normals" who don't have CRDs. But their responses to light and dark cues differ from those of CRD patients. Please conduct circadian research on CRD patients--just as you would conduct diabetes research on diabetics.

Also needed: convenient ways to test for dim light melatonin onset, temperature nadir, and other circadian biomarkers. Right now, such tests are limited to study settings.

Addressing this CQ is a sine-qua-non for individualized medicine. Especially in the case of physiological and long-term health responses to sleep loss, the differential vulnerability trait and the underlying mechanisms are not well characterized. However, as seen in the cognitive domain, investigating individual differences can help elucidate the underlying mechanisms. Thus, this should be a fruitful line of research not only in the context of individual differences per se, but also for better understanding the link(s) between sleep loss and adverse health outcomes in general.

This CQ can be addressed by adopting a systems (neuro)biology approach in which individual differences are considered at the systems components level rather than the whole organism level. For example, the task-dependence of individual differences in vulnerability to cognitive impairment due to sleep loss may be investigated at the level of neuronal circuits that subserve performance of the task at hand, rather than at (or in conjunction with) the whole brain / genetic level. A significant challenge in this regard is that in the case of physiological and health responses to sleep loss, the differential vulnerability trait and the underlying mechanisms are not yet well characterized. See "Details On The Impact Of Addressing This CQ".

Sleep disorders are more common in minority populations. Moreover, these populations have higher rates of the known consequences of these disorders such as stroke, myocardial infarction, hypertension, resistant hypertension. Despite this, current population studies such as the Sleep Heart Health Study have included only a very small percentage of African Americans. The impact of this would be the following:

a. Elucidating the basis of barriers to case identification in these group
b. Designing specific intervention to overcome these barriers.
c. Developing methods to improve adherence to therapy in this group.
d. Removing sleep and circadian disorders as a risk factor for consequences such as stroke, cardiovascular disease and resistant hypertension in minority populations

There is a developing interest in this area in the field of circadian and sleep research. There is a developing knowledge base about health disparities in sleep and circadian disorders. Minority institutions such as Morehouse have developing programs in this area. We also have mobile technology that facilitates study of sleep and circadian disorders in minority populations.

Much of the research on the consequences of sleep/circadian disorders has focused on their consequences or behavior. This type of research needs to be continued and there are new opportunities in this area. These behavioral studies need to be established in model systems to parallel studies in humans. In addition, new neurobiological approaches, including optogenetics and use of DREAD, provide new tools for this investigation. Moreover, we now have powerful molecular tools to evaluate effects of sleep/circadian disorders both in humans and animal models. These include microarrays, RNA seq, etc. Moreover, genetic studies, e.g., in restless legs syndrome, have identified gene variants conferring risk for the disorder. We do not know, however, how these particular genes are involved in the pathogenesis of the disorder or whether they represent potentially targets for drug intervention. There is a need for studies both in animal models and in humans to elucidate the function of these genes. Studies in other areas are obtaining stem cells from biopsies in patients and then turning these into relevant target cells such as neurons to elucidate gene function using in vitro approaches.
The impact of this effort will be the following:

a. Taking our understanding of pathogenesis of sleep and circadian disorders to a new level.
b. Understanding the consequences of sleep and circadian disorders on different end organs at a more in-depth molecular level.

The sleep and circadian field have access to all the major cells systems for these studies—C. elegans, aplysia, Drosophila, zebra-fish, mice, etc. Moreover, there are already gene variants identified in human studies which require follow-up functional studies. The field has the expertise in all of the techniques described above. Moreover, there are more validated animal models for many of the common sleep disorders. Thus, this new approach is very feasible. 

This question will have considerable impact. Sleep apnea is an independent risk factor for insulin resistance. Moreover, observational studies show that treatment of OSA reduces the rate of future diabetes compared to that which occurs in untreated OSA. Therefore, identifying OSA and treating this could have a profound impact on reducing the rate of diabetes, i.e., a preventative strategy.

Both sleep loss and obstructive sleep apnea have also been shown to be risk factors for subsequent development of Alzheimer’s disease. This has been shown in mouse models and in epidemiological studies to address whether insufficient sleep and sleep apnea are independent risk factors for development of Alzheimer’s disease, in particular accelerating their onset. Determining whether this is so and whether interventions to treat these sleep disorders delay onset of diabetes and Alzheimer’s disease would have profound public health significance.

These disorders are extremely common so that recruitment of subjects is not challenging. Moreover, new technology reduces protocol burden to assess individuals. All studies can be done in the patients’ home. There are existing cohort studies focused on diabetes and the Alzheimer’s Center program that could be used for these studies. Thus, the studies are extremely feasible in the near term.

Sleep and circadian disorders are extremely common. For many of these we know little about the natural history, whether different subgroups exist and effects of current therapies. Thus, developing specific registries for common sleep and circadian disorders would provide a basis for addressing these questions.

For some aspects, e.g., studies of inadequate sleep, impact of snoring and circadian disruption, would be facilitated by developing a specific sleep/circadian cohort with in-depth phenotyping. This strategy has worked extremely well in other areas, e.g., cardiovascular disease. The lack of this type of cohort for sleep and circadian disorders is a barrier to progress in this area. The high prevalence of these disorders and their known public health significance argue that development of such a cohort would be a game changer and accelerate progress in this new area of medicine.

Such a cohort could address several compelling questions:

a. What is the natural history of short sleep across the lifespan?
b. What is the impact of snoring? Does it lead, as has been proposed, to vibration injury to carotid arteries with accelerated vessel wall damage?
c. Are there different subtypes of individuals with the different sleep and circadian disorders?
d. What is the natural history of shift-workers and what types of shifts lead to increased risk for cardiovascular disease?

Problems with sleep and circadian rhythm and the relevant disorders are common. There are multiple accredited sleep centers for clinical purposes in the United Sates. They use common phenotyping platforms that could be the basis of some aspects of addressing this critical challenge. Moreover, most CTSA programs have a sleep study component. There are patient support groups for sleep apnea, insomnia, restless legs syndrome and narcolepsy. Thus, these groups could be marshaled to help in this effort. There is already a Sleep Research Network that was founded by the field itself. It is currently based on volunteer effort and there are no resources to support it. It could be the basis for future activities in this area.

The current status of research training in sleep and circadian disorders suggest that new approaches are needed. The field has developed one multi-center training grant to bring training to different institutions. This is focused on genetic/genomic approaches. It is run by the University of Pennsylvania which has a well developed program in this area. The fellows in training are, however, at other institutions, i.e., Johns Hopkins, University of Michigan and Stanford. Web-based approaches are used for work-in-progress seminars, grant development workshops and group mentorship, and didactic lectures. This strategy could be used more broadly to develop research training in other areas of sleep and circadian research. Stimulating this would have a major impact on research training in this new field of medicine.

Another relevant strategy would be to encourage adding slots in a competitive way for sleep/circadian research to other existing institutional T32 grants.

There are multiple mechanisms in place to communicate opportunities to the sleep/circadian academic community, i.e., Sleep-L, administered by the National Center for Sleep Disorders Research; Sleep Research Society biweekly blog; the Sleep Research Network. Specific encouragement of this approach would broaden the base for research training and would be of high impact.

The field of sleep and circadian research has had a long commitment to facilitating research training. The Sleep Research Society has hosted Trainee Day at our annual meeting for 20 years. The Sleep Research Society is funding early-stage investigators through its Foundation. The American Academy of Sleep Medicine runs, in collaboration with the NHLBI, an event at NIH for early-stage investigators in clinical research. The American Academy of Sleep Medicine Foundation has a “Bridge to K Award” program that provides funds to early-stage investigators who just missed funding on their first application for a K award. The Sleep Research Society has provided travel funds for early-stage investigators to attend recent workshops held by different NIH Institutes including National Heart, Lung and Blood Institute. Thus, there is no doubt of the commitment of the field and its professional organizations.

The impact of these new initiatives would be to broaden the base for research training beyond a few institutions. The number of institutions with a critical mass of investigators to mount successful T32 institutional training grants is not sufficient to provide the necessary future biomedical research workforce in this area. Novel approaches, based on modern communication IT technology, are needed.

The following will be the impact of addressing this critical challenge:

1. Having an assessment that can be used following a crash to assess the level of sleep loss of the driver.
2. Having a method to assess chronic sleep insufficiency as a potential pathogenetic process in patients with cardiovascular disease, hypertension, etc.
3. Having a method to estimate circadian phase so that in patients with chronic insomnia one can identify individuals with delayed sleep phase.
4. Having a technique to establish magnitude of circadian disruption to assess its role in pathogenesis of diseases such as cardiovascular disease.
5. Add a molecular biomarker to other techniques to screen for obstructive sleep apnea in high risk populations such as obese commercial drivers.
6. Utilize a biomarker signature to identify who with obstructive sleep apnea will be particularly at risk for downstream consequences such as cardiovascular disease.
7. Develop the equivalent of HbA1C to assess therapeutic response to CPAP

The first challenge is to identify a signature for each of these use cases. This will require initial studies in a small number of well phenotyped subjects with all the “-omic” techniques. Thereafter, these multiple cohorts, already available with blood samples, etc. and relative phenotype can be used for validation purposes.