SLEEP MEDICINE AND ESSENTIAL HYPERTENSION IN ADOLESCENTS

The review describes current understanding of the problem of essential hypertension from a perspective of sleep medicine. Sleep disorders in adolescents can be considered as one of constant symptoms of essential hypertension, which are found not only on initial (functional) stages of this disease and but also in the course of the illness. It is now known that about 90 % of sleep disorders are represented by different types of such respiratory disturbances as obstructive sleep-disordered breathing (obstructive sleep apnea/hypopnea syndrome). Considering close interaction between hemodynamic and respiratory systems we can assume possible participation of sleep-disordered breathing in the development of essential hypertension in adolescents

THE ROLE OF SLEEP AND ITS DISORDERS IN FORMING OF COGNITIVE FUNCTIONS IN CHILDHOOD (LITERATURE REVIEW)

The article summarizes and analyzes scientific literature data concerning modern ideas about sleep as a key element in formation of cognitive functions in children, encephalographic patterns during the night as markers of intellectual abilities in healthy children are described. Decline in mental abilities of the child should be considered as one of the permanent symptoms in those or other sleep disorders. It is now known that about 90 % of sleep disorders is presented different types of respiratory disorders. Using of modern high-tech methods of sleep research, diagnosis and treatment of sleep disorders will prevent the formation of cognitive impairment and improve the overall intellectual potential of the younger generation

MODERN IDEAS OF “SLOW SLEEP” AND “REM-SLEEP” AND THEIR ROLE IN PATHOGENESIS OF ALZHEIMER’S DISEASE (REVIEW OF LITERATURE)

This review discusses the data of new researches on the functional purpose of sleep and its stages, and its role in the development of pathological conditions. The main modern hypotheses and concepts about a role of slow sleep and REM-sleep (rapid eye movement) are interpreted. The visceral theory of slow sleep as an activator of restorative processes in the brain and manager of internal organs functions is described. A brain "drainage" function of slow sleep is known. Recent studies suggest sleep-wake disturbances, for example, obstructive apnea syndrome, may influence Alzheimer's disease (AD) onset and progression. Possible mechanisms such asfunctional disorders of brain lymphatic system during slow sleep and the extracellular accumulation of the amyloid-ß (Aß) peptide underlying the relationship between the sleep-wake disturbances and AD are described. The role of REM-sleep in the formation of the central nervous system in the early postnatal period and the performance of the function of mental adaptation are discussed. In this article, we presented data about the role both of neurotransmitters and neuropeptides in the regulation of sleep-wake cycle and the maintenance of wakefulness and REM-sleep. The possible new approach to the forecasting of cognitive and emotional-affective disorders in sleep disturbances is substantiated from the perspective of modern neuroscience and sleep neurophysiology still in childhood is justified

Sleep disorders and obesity in adolescents: peculiarities of psycho-cognitive status (literature review)

Adolescence is a time of important physical, cognitive, emotional, and social changes. Sleep is a primary aspect of adolescent development. Its disorders critically influence adolescents' ability to think, behave, and feel during daytime hours. Daytime activities, changes in the environment, and individual factors can have significant effects on adolescents' sleeping patterns. It is known, that a significant change of the sleep-wake cycle across adolescent development is a tendency to stay up later at night and to sleep in later in the morning. The peculiarity of this period of life is called a sleep delayed phase phenomenon, which can play the important role in the development of eating disorders and cause risk of obesity. The epidemic of childhood obesity presents a major public health problem. Many authors consider that obesity is a multisystem disease with potentially devastating consequences for physical and emotional health across the lifespan. Obesity may cause obstructive sleep apnea syndrome that can result in excessive daytime sleepiness in adolescents and have a negative effect on learning, school performance, and behavior. Early detection of risk factors, screening for metabolic and sleep disturbances in adolescents are major aims in reducing risk of cognitive and behavioral disorders. We assume that further studies of the psycho-cognitive impairments in adolescents with obesity in the sleep-wake continuum are necessary for the development of new approaches to forecasting, early diagnosis and pathogenically therapies of emotional and cognitive changes at the stage of personality formation as well as potentially reversible sleep and metabolic disorders

Obesity and Circadian Cycle of Sleep and Wakefulness: Common Points and Prospects of Therapy

The prevalence of obesity in recent years has assumed the character of a non-communicable epidemic. Wherein, the standard approaches for its treatment are not always successful. Meanwhile, obesity remains one of the main causes of the formation of a number of some serious diseases, such as cardiovascular, diabetes, cancer, etc. and death from them. In search of alternative and more adequate methods of obesity treatment and preventing its complications, recent studies are aimed at further identifying new associations and revealing the pathophysiological mechanisms underlying excessive weight gain. It should be noted an increasing amount of chronobiological studies that raised awareness of the key role of the body’s circadian rhythms and its main regulator, melatonin, responsible for the temporary organization of the main physiological (including metabolism) processes throughout the 24-h day, in the development and progression of obesity. This review is devoted to the consideration of mutually directed interactions between the circadian system and metabolism; attempts have been made to explain the role of sleep-wake cycle disruptions in the excess accumulation of adipose tissue and the formation of obesity and its comorbidities, as well as detailed therapeutic principles based on normalizing disruption of body clocks using time-coordinated approaches to food intake, physical activity, the effects of non-drug methods and pharmacological substances (chronobiotics), which represents a novel and promising ways to prevent or treat obesity and associated diseases

DISTINCTIVE FEATURES OF HORMONAL STATUS IN MALE ADOLESCENTS WITH ESSENTIAL HYPERTENSION AND OBSTRUCTIVE SLEEP APNEA

Background. It is known that obstructive sleep apnea (OSA) has been closely linked to essential hypertension (EH) and is considered as an important stressor. The hypothalamic-pituitary-adrenal axis (HPA) is a major component involved in stress response. However, the response of HPA axis to OSA effects may be variable. Aim: to estimate hormonal status in OSA and non-OSA adolescents with EH. Methods. We examined 38 male adolescents with EH (18 OSA patients - group A, 20 non-OSA patients - group B) aged 14-17 years. OSA was verified by polysomnography applying system GRASS-TeLeFACTOR Twin PSG (Comet, USA). EH was diagnosed with 24-h ambulatory blood pressure monitoring using monitor Oscar 2 for OXFORD Medilog Prima. Hormonal status, including thyroid-stimulating hormone (TSH), prolactin (PRL) and cortisol, were routinely collected using an automatic analyzer «Cobos ELL» (USA) and test-system «Alcor-bio» (Russia). All differences were considered significant at p < 0.05. Results. There were statistically significant differences in morning serum cortisol level of OSA adolescents (745.8 ± 6.4 nmol/L versus 493.2 ± 3.2 nmol/L in non-OSA participants; р < 0.05). Morning serum PRL and TSH levels in the both groups no statistically significant differences, but there is a trend towards its increasing in OSA adolescents with EH (482.8 ± 4.2 mME/L in the group A and 442.2 ± 4.1 mME/L in the group B, and 1.95 ± 0.9 mkME/ml versus 1.5 ± 0.2 mkME/ml, respectively, р < 0.05). Conclusion. The results of this study indicate for chronic stress if OSA in adolescents with EH is present. This is due to the influence of sleep fragmentation and intermittent hypoxia on HPA axis with compensatory stress-related hormones release

Obstructive Sleep Apnea Syndrome and Features of the Neurophysiological Sleep Pattern

The high prevalence of obstructive sleep apnea syndrome (OSA) causes a steady interest in this pathology. In recent years, one of the urgent problems in modern somnology is the assessment of the main mechanisms of neuronal dysfunction during the day and at night in OSA, the ideas about which, to a large extent, remain contradictory and not fully understood. One of the modern methods for assessing neuronal dysfunction during sleep is the study of the sleep microstructure, and for its assessment, the method of analysis of cyclic alternating pattern (CAP), an EEG marker of unstable sleep, is used. The cyclic alternating pattern is found both in the sleep of adults and children with various sleep disorders and, in particular, with OSAS, therefore, it is a sensitive tool for studying sleep disorders throughout life. With the elimination of night hypoxia against the background of CPAP therapy, the sleep microstructure is restored, the spectral characteristics of the EEG change, and a decrease in the number of EEG arousals after treatment leads to the restoration of daytime functioning. Understanding the role of short-term EEG activations of the brain during sleep can provide significant data on sleep functions in health and disease. Despite the improving diagnosis of sleep disorders using machine algorithms, assessing the relationship of structures and functions of the brain during sleep, neurophysiological data are not entirely clear, which requires further research. In this review, we tried to analyze the results of the main studies of the neurophysiological sleep pattern in OSA against the background of respiratory support during sleep

Prevalence of sleep disorders in teenage girls in Irkutsk (questionnaire data)

Background. Adequate sleep ensures a person’s physical and psycho-emotional well-being. Adolescence is one of the critical stages of life. The exclusive attention of specialists and leveling the impact of adverse factors on the body during this period is the key to the proper development and preservation of the health of adolescents. Meanwhile, sleep problems in teenage girls remain poorly understood.The aim. To study the features of the sleep regime and quality of sleep of teenage girls in the city of Irkutsk.Materials and methods. A survey of 422 teenage girls in the city of Irkutsk was conducted using a translated version of a questionnaire about adolescent sleep habits to subjectively assess their sleep and wakefulness. Two groups were formed: group I – girls with sleep problems (n = 171); group II – girls without sleep problems (n = 251).Results. Sleep disorders among teenage girls in the city of Irkutsk occurred with a frequency of 40.52 %. In most cases, a complex effect of various unfavorable factors on the sleep process has been identified. The adolescents with sleep disorders we  examined were characterized by higher rates of sleep latency, later bedtime, earlier awakening, decreased time of night sleep, as well as changes in the sleep shift indicator towards its increase. These violations were noted both on weekdays and on weekends.Conclusions. Sleep problems were reported in 40.52% of respondents. The complex impact of various unfavorable factors on sleep quality has been revealed. The features of sleep hygiene of teenage girls are reflected. The group of girls with sleep problems was characterized by increased sleep latency, later bedtime, earlier awakening, reduced sleep time, and an increase in sleep shift

ETHNIC PECULIARITIES OF SLEEP DISORDERS IN EASTERN SIBERIA

The purpose of this investigation was to study the ethnic peculiarities of sleep disorders in European and Mongoloid races living in Eastern Siberia. In this study we performed questioning of409 respondents of Europeans (Russian) 203 (49.63 %) and Mongoloid (Buryats) 206 (50.37 %) aged 20-60 years. Living in the Irkutsk region and the Buryat Republic. Gender structure: 270females (66.9 %) and 125 males (33.1 %). Standard questionnaire of Stanford Sleep Research Center (USA) included a complex of questions about problems of sleep and their subjective assessment: no problems; light problem, moderate problem, severe problem. PSG-monitoring applying system GRASSTELEFACTOR Twin PSG (Comet) with amplifier As 40 with integrated module for sleep SPM-1 (USA). It was revealed that "light" sleep problems note 25.1 % of native ethnic group respondents (Buryats) and 38.3 % of Russian respondents (p < 0.05). The moderate sleep disorders were characteristic of 8.7 % Buryats and 3.1 % Russian (p < 0.05), and the severe sleep disorders 5.3 % and 2.2 %, respectively (p < 0.05). Severe sleep disorders noted 7.2 % Buryat women versus 1.8 % in the group of Russian women (p < 0.05), among men the severe sleep disorders is significantly higher (23.8 % in the Buryats and Russian 14.6 %, p < 0.05). We identified correlation between body mass index (BMI) and obstructive sleep apnea (OSA) in males of Mongoloid race (with OSA BMI was 33.37 kg/cm2, without 24.86 kg/cm2, p < 0.05). According to the results of the PSG study in males of the both ethnic groups, a higher incidence of moderate and severe OSA in the Buryats (28.2 % and 20.1 %, respectively, p < 0.05). In general, these results confirm the presence of more severe sleep disorders in Mongoloids (including OSA), but certain anatomical features for the formation of OSA we have not found, that require further study

Obstructive sleep apnea and amyloid-β42 in adolescents: The results of a pilot study

Background. Obstructive sleep apnea (OSA) is a chronic condition characterized by repetitive collapse of the upper airway during sleep leading to intermittent hypoxia, excessive arousals and disrupt of sleep homeostasis. OSA is associated with obesity as well as pathological dynamics of cerebral beta-amyloid and dementia.The aim. Comparative assessment of the plasma beta-amyloid 42 levels in adolescents, depending on the presence or absence of OSA and obesity.Materials and methods. Seventy-four obese and non-obese male adolescents were included in the study. All participants underwent polysomnography to verify OSA and measure sleep parameters, and venipuncture for the assessment of betaamyloid 42 by enzyme-linked immunosorbent assay (ELISA).Results. After polysomnography all adolescents have been divided into four study groups: OSA obese (group 1; n = 28); non-OSA obese (group 2; n = 20); OSA non-obese (group 3; n = 11), and non-OSA non-obese (group 4 – control; n = 15). OSA obese adolescents had significant elevations in beta-amyloid 42 plasma levels compared with participants from three other groups (р = 0.007, p = 0.047 and p = 0.0002, correspondingly). Compared to both OSA non-obese adolescents and the control group, non-OSA obese patients had similar beta-amyloid 42 blood concentrations (p = 0.167 and p = 0.155, correspondingly). However, patients from the group 3 showed significantly higher beta-amyloid 42 plasma levels than controls (p = 0.004).Conclusions. Thus, OSA, accompanied by intermittent nocturnal hypoxia, and particularly OSA and obesity comorbidity, in adolescents is associated with increased beta-amyloid 42 circulating concentrations, which has a major role in pathogenesis of dementia. Beta-amyloid 42 plasma level may be recommended for use as early biomarker of cognitive impairment and neurodegenerative diseases, but future researches are needed