Sleep apnea: epidemiology, pathophysiology, and relation to cardiovascular risk

Obstructive sleep apnea syndrome in polycystic ovary syndrome: a systematic review and meta-analysis

Background

Polycystic ovary syndrome (PCOS) has been associated with a high prevalence of obstructive sleep apnea syndrome (OSAS). However, the impact of OSAS on the PCOS symptom profile remains unclear. This systematic review and meta-analysis, which informed the 2023 International Evidence-based PCOS Guideline, aims to assess the prevalence and related symptoms of OSAS among females with and without PCOS.

Methods

A systematic search using databases (MEDLINE, Embase, EBM Reviews, PsycInfo and CINAHL) was performed until 16th May 2024. Random-effects restricted maximum likelihood meta-analyses compared OSAS and related symptoms between PCOS and non-PCOS groups. OSAS outcomes were categorized as apnea-hypopnea index (AHI)≥5 only, AHI≥5 with symptoms, AHI≥10 with symptoms and composite OSA (i.e., all AHI cut-offs with and/or without symptoms). Subgroup analyses by body mass index (BMI), age, PCOS diagnostic criteria and ethnicity were performed. Risk of bias and certainty of evidence by the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) framework were conducted.

Results

From 4438 records, 3205 titles/abstracts were screened and 40 were eligible for full-text screening. Eight cross-sectional studies met inclusion criteria and meta-analysis. The pooled prevalence of OSA was 37.0% in PCOS (29.0% adolescents; 40.0% adults) and 6.0% in non-PCOS. Compared with non-PCOS, those with PCOS showed higher risk for composite OSA (odds ratio (OR): 9.52; 95% CI: 3.90 to 23.26; I 2 = 54.5%; 8 studies, n=942; P<0.001) and more pronounced OSAS risk with increasing symptom severity in PCOS (AHI≥5 OR: 3.90; 95% CI: 1.63 to 9.34; AHI≥5 with symptoms OR: 17.95; 95% CI: 6.17 to 52.22; AHI≥10 with symptoms OR: 30.61; 95% CI: 7.99 to 117.25, all P ≤ 0.0023). Subgroup results showed significantly higher risk of OSAS overall in overweight/obesity, adults and white ethnicity compared with normal weight, adolescent and Asian subgroups, respectively (all P<0.001), but independent of PCOS diagnostic criteria.

Conclusion

The prevalence of OSA was higher in PCOS compared with non-PCOS groups, with the risk of OSAS increasing with worse symptom severity. Adults and those of higher BMI and of white ethnicity were at increased risk of OSAS. Hence, identifying and treating OSAS symptoms in PCOS may be beneficial, but further validation of findings is warranted.

Racial differences in upper airway collapsibility and loop gain in young adult males

STUDY OBJECTIVES

Previous studies reported that the apnea-hypopnea index was similar in young adult Black and White participants. However, whether this similarity reflects an analogous combination of apneas and hypopneas is unknown. Likewise, the physiological mechanisms underlying this similarity has not been explored.

METHODS

60 Black and 48 White males completed the study. After matching for age and body mass index, 41 participants remained in each group. All participants completed a sleep study. Subsequently, standard sleep indices along with loop gain and the arousal threshold were determined. In addition, airway collapsibility (24 of 60 and 14 of 48 participants) and the hypoxic ventilatory response during wakefulness (30 of 60 and 25 of 48 participants) was measured.

RESULTS

The apnea-hypopnea index was similar in Blacks and Whites (p = .140). However, the index was comprised of more apneas (p = .014) and fewer hypopneas (p = .025) in Black males. These modifications were coupled to a reduced loop gain (p = .0002) and a more collapsible airway (p = .030). These differences were independent of whether or not the groups were matched. For a given hypoxic response, loop gain was reduced in Black compared to White males (p = .023).

CONCLUSIONS

Despite a similar apnea-hypopnea index, more apneas and fewer hypopneas were evident in young adult Black compared to White males. The physiological mechanisms that contribute to these events were also different between groups. Addressing these differences may be important when considering novel therapeutic approaches to eliminate apnea in Black and White participants.

Sex Differences in Neurovascular Control: Implications for Obstructive Sleep Apnea

Patients with obstructive sleep apnea (OSA) have a heightened risk of developing cardiovascular diseases, namely hypertension. While seminal evidence indicates a causal role for sympathetic nerve activity in the hypertensive phenotype commonly observed in patients with OSA, no studies have investigated potential sex differences in the sympathetic regulation of blood pressure in this population. Supporting this exploration are large-scale observational data, as well as controlled interventional studies in healthy adults, indicating that sleep disruption increases blood pressure to a greater extent in females relative to males. Furthermore, females with severe OSA demonstrate a more pronounced hypoxic burden (i.e., disease severity) during rapid eye movement sleep when sympathetic nerve activity is greatest. These findings would suggest that females are at greater risk for the hemodynamic consequences of OSA and related sleep disruption. Accordingly, the purpose of this review is three-fold: (1) to review the literature linking sympathetic nerve activity to hypertension in OSA, (2) to highlight recent experimental data supporting the hypothesis of sex differences in the regulation of sympathetic nerve activity in OSA, and (3) to discuss the potential sex differences in peripheral adrenergic signaling that may contribute to, or offset, cardiovascular risk in patients with OSA.

Obstructive Sleep Apnea: A Look towards Micro-RNAs as Biomarkers of the Future

Sleep-disordered breathing (SDB) includes a broad spectrum of diseases, of which obstructive sleep apnea syndrome (OSA) is the most clinically significant manifestation. OSA is a respiratory disorder characterized by episodes of complete or partial obstruction of the upper airways that disturb ventilation and sleep architecture. In recent years, interest in the clinical implications of OSA seems to have increased, probably due to the numerous studies that have shown the existence of an important correlation between OSA and cardiovascular, dysmetabolic, and neoplastic changes. The guidelines currently available highlight the importance of diagnosis and effective treatment for OSA, underlining the need for new biomarkers that are useful in clinical practice, feasible, and reproducible to guide medical decision making. In this review, we intend to provide an overview of the potential role of microRNAs as new indicators for OSA management. MicroRNAs (miRNAs) are small non-coding RNA molecules that play an important role in RNA silencing and regulation of gene expression at the post-transcriptional level. These can bind specifically to their target genes by forming silencing complexes, thus inducing degradation or altered gene expression. A wide range of miRNAs have been extensively studied in a variety of diseases including cancer, and recently, miRNAs have been shown to have enormous potential to function as diagnostic and clinical biomarkers of disease. This review includes recent studies that establish the inevitable role of miRNAs in the pathogenesis of OSA.

Pulse oximetrySpO2signal for automated identification of sleep apnea: a review and future trends

Sleep apnea (SA) is characterized by intermittent episodes of apnea or hypopnea paused or reduced breathing, respectively each lasting at least ten seconds that occur during sleep. SA has an estimated global prevalence of 200 million and is associated with medical comorbidity, and sufferers are also more likely to sustain traffic- and work-related injury due to daytime somnolence. SA is amenable to treatment if detected early. Polysomnography (PSG) involving multi-channel signal acquisition is the reference standard for diagnosing SA but is onerous and costly. For home-based detection of SA, single-channelSpO₂signal acquisition using portable pulse oximeters is feasible. Machine (ML) and deep learning (DL) models have been developed for automated classification of SA versus no SA usingSpO₂signals alone. In this work, we review studies published between 2012 and 2022 on the use of ML and DL forSpO₂signal-based diagnosis of SA. A literature search based on PRISMA recommendations yielded 297 publications, of which 31 were selected after considering the inclusion and exclusion criteria. There were 20 ML and 11 DL models; their methods, differences, results, merits, and limitations were discussed. Many studies reported encouraging performance, which indicates the utility ofSpO₂signals in wearable devices for home-based SA detection.

EVs-miRNA: The New Molecular Markers for Chronic Respiratory Diseases

Idiopathic pulmonary fibrosis (IPF), chronic obstructive pulmonary disease (COPD), asthma and sleep disorders are chronic respiratory diseases that affect the airways, compromising lung function over time. These diseases affect hundreds of millions of people around the world and their frequency seems to be increasing every year. Extracellular vesicles (EVs) are small-sized vesicles released by every cell in the body. They are present in most body fluids and contain various biomolecules including proteins, lipids, mRNA and non-coding RNA (micro-RNA). The EVs can release their cargo, specifically micro-RNAs (miRNAs), to both neighboring and/or distal cells, playing a fundamental role in cell-cell communication. Recent studies have shown their possible role in the pathogenesis of various chronic respiratory diseases. The expression of miRNAs and, in particular, of miRNAs contained within the extracellular vesicles seems to be a good starting point in order to identify new potential biomarkers of disease, allowing a non-invasive clinical diagnosis. In this review we summarize some studies, present in the literature, about the functions of extracellular vesicles and miRNAs contained in extracellular vesicles in chronic respiratory diseases and we discuss the potential clinical applications of EVs and EVs-miRNAs for their possible use such as future biomarkers.

Assessing the needs and perspectives of patients with obesity and obstructive sleep apnea syndrome following continuous positive airway pressure therapy to inform health care practice: A focus group study

Objective

This study aims to investigate the lived experience in patients with obstructive sleep apnea syndrome (OSAS) and comorbid obesity following after continuous positive airway pressure (CPAP) therapy made with the disease the device, and to identify barriers and facilitators to the use of CPAP to improve rehabilitation provision and aid in disease self-management.

Methods

Qualitative research was conducted using three focus groups with a representative sample of 32 inpatients (37% female) undergoing a 1-month pulmonary rehabilitation program at the IRCSS Istituto Auxologico Italiano San Giuseppe Hospital, Verbania, Italy. The focus groups were recorded on tape, and contemporaneous notes were made. The tapes were transcribed verbatim, and Interpretative Phenomenological Analysis was used to develop themes.

Results

Six main themes were extracted: (1) Living the diagnosis as a shock; (2) You should not sleep on it: the importance of prevention; (3) The adjustment to CPAP; (4) Barriers and facilitators to the use of CPAP; (5) Three in a bed; and (6) The relationship with the healthcare system.

Conclusion

Results of this study suggest potential avenues for interventions to increase adherence to CPAP, including the provision of information and continued support. Individual counseling providing strategies aimed at helping the person to cope with the emotional problem and relational difficulties associated with the use of CPAP, and at strengthening self-efficacy and self-management skills are also encouraged for optimal care during the rehabilitation program.

Disturbances of the Gut Microbiota, Sleep Architecture, and mTOR Signaling Pathway in Patients with Severe Obstructive Sleep Apnea-Associated Hypertension

Intermittent hypoxia and sleep fragmentation are pathophysiological processes involved in obstructive sleep apnea (OSA) which affect gut microbiota, sleep architecture, and mTOR signaling pathway. However, the involvement of these elements in the pathogenesis mechanism of OSA-associated hypertension remains unclear. Therefore, this study investigated whether the OSA-associated hypertension mechanism is regulated by the gut microbiota and mTOR signaling pathway. Patients were diagnosed by polysomnography; their fecal samples were obtained and analyzed for their microbiome composition by 16S ribosomal RNA pyrosequencing and bioinformatics analysis. Transcript genes on fasting peripheral blood mononuclear cells (PBMCs) were examined using Illumina RNA-sequencing analysis. Totally, we enrolled 60 patients with severe OSA [without hypertension (n = 27) and with hypertension (n = 33)] and 12 controls (neither OSA nor hypertension). Results revealed that severe-OSA patients with hypertension had an altered gut microbiome, decreased short-chain fatty acid-producing bacteria (P < 0.05), and reduced arginine and proline metabolism pathways (P=0.001), compared with controls; also, they had increased stage N1 sleep and reduced stages N2 and N3 sleep accompanied by repeated arousals (P < 0.05). Analysis of PBMCs using the Kyoto Encyclopedia of Genes and Genomes database showed that the mTOR signaling pathway (P=0.006) was the most important differential gene-enriched pathway in severe-OSA patients with hypertension. Our findings extend prior work and suggest a possibility that the regulation of the mTOR signaling pathway is involved in developing OSA-associated hypertension through its interaction with the disturbance of the gut microbiome and sleep architecture.

Pathophysiology of Obstructive Sleep Apnea in Aging Women

The following review is designed to explore the pathophysiology of sleep apnea in aging women. The review initially introduces four endotypes (i.e., a more collapsible airway, upper airway muscle responsiveness, arousal threshold, and loop gain) that may have a role in the initiation of obstructive sleep apnea. Thereafter, sex differences in the prevalence of sleep apnea are considered along with differences in the prevalence that exist between younger and older women. Following this discussion, we consider how each endotype might contribute to the increase in prevalence of sleep apnea in aging women. Lastly, we address how modifications in one form of respiratory plasticity, long-term facilitation, that might serve to mitigate apneic events in younger women may be modified in aging women with obstructive sleep apnea. Overall, the published literature indicates that the prevalence of sleep apnea is increased in aging women. This increase is linked primarily to a more collapsible airway and possibly to reduced responsiveness of upper airway muscle activity. In contrast, modifications in loop gain or the arousal threshold do not appear to have a role in the increased prevalence of sleep apnea in aging women. Moreover, we suggest that mitigation of long-term facilitation could contribute to the increased prevalence of sleep apnea in aging women.

Capnometric feedback training decreases 24-h blood pressure in hypertensive postmenopausal women

BACKGROUND

High normal resting pCO₂ is a risk factor for salt sensitivity of blood pressure (BP) in normotensive humans and has been associated with higher resting systolic BP in postmenopausal women. To date, however, no known studies have investigated the effects of regular practice of voluntary mild hypocapnic breathing on BP in hypertensive patients. The objective of the present research was to test the hypothesis that capnometric feedback training can decrease both resting pCO₂ and 24-h BP in a series of mildly hypertensive postmenopausal women.

METHODS

A small portable end tidal CO₂ (etCO₂) monitor was constructed and equipped with software that determined the difference between the momentary etCO₂ and a pre-programmed criterion range. The monitor enabled auditory feedback for variations in CO₂ outside the criterion range. 16 mildly hypertensive postmenopausal women were individually trained to sustain small decreases in etCO₂ during six weekly sessions in the clinic and daily sessions at home. 24-h BP monitoring was conducted before and after the intervention, and in 16 prehypertensive postmenopausal women in a control group who did not engage in the capnometric training.

RESULTS

Following the intervention, all 16 capnometric training participants showed decreases in resting etCO₂ (- 4.3 ± 0.4 mmHg; p < .01) while 15 showed decreases in 24-h systolic BP (- 7.6 ± 2.0 mmHg; p < .01). No significant changes in either measure was observed in the control group. In addition, nighttime (- 9.5 ± 2.6; p < .01) and daytime (- 6.7 ± 0.2 mmHg) systolic BP were both decreased following capnometric training, while no significant changes in nighttime (- 2.8 ± 2.2 mmHg; p = .11) or daytime (- 0.7 ± 1.0 mmHg; p ≤ .247) systolic BP were observed in the control group.

CONCLUSIONS

These findings support the hypothesis that regular practice of mild hypocapnic breathing that decreases resting etCO₂ reliably decreases 24-h blood pressure in hypertensive postmenopausal women. The extent to which these effects persist beyond the training period or can be observed in other hypertensive subgroups remains to be investigated.

The effect of treatment of obstructive sleep apnea syndrome on overactive bladder symptoms

OBJECTIVE

To evaluate the effect of the treatment of obstructive sleep apnea syndrome on overactive bladder symptoms.

METHODS

All patients who applied to the outpatient clinic with complaints of snoring and apnea were evaluated by polysomnography between years 2017 and 2019. obstructive sleep apnea syndrome severity was evaluated according to the apnea-hypopnea-index. All patients were filled with questionnaire form as overactive bladder symptoms score, international quality of life, international consultation on incontinence questionnaire short-form, and 3-day bladder diary before polysomnography and three months after continuous positive airway pressure therapy and surgical treatment.

RESULTS

A total of 125 patients, 34 (27.2%) patients with mild obstructive sleep apnea syndrome, 27 (21.6%) patients with moderate obstructive sleep apnea syndrome, and 64 (51.2) patients with severe obstructive sleep apnea syndrome were included in the study. The prevalence of overactive bladder symptoms in three obstructive sleep apnea syndrome groups were 67.6, 53.8, and 48.4%, respectively, and there was no statistical difference between the groups (p=0.190). obstructive sleep apnea syndrome treatment such as surgical treatment or continuous positive airway pressure therapy was applied to 45.5% (31 patients) patients with obstructive sleep apnea syndrome and overactive bladder. Three months after treatment, the overactive bladder symptoms score significantly decreased from 16.1±7.9-12.80±9.82, international quality of life was significantly increased from 105.0±23.2-110.4±22.2, and incontinence questionnaire short-form decreased from 11.9±4.0-10.4±5.6 (p=0.009, p=0.023, and p=0.248, respectively). There was a significant decrease between before and after treatment in terms of mean day-time frequency and mean urgency episodes of patients (p=0.007, p=0.002).

CONCLUSIONS

Both surgery and continuous positive airway pressure treatment of obstructive sleep apnea syndrome improved overactive bladder symptoms, overactive bladder symptoms score, international quality of life, day-time frequency, and urgency episodes.

Assessment of Cardiorespiratory Interactions during Apneic Events in Sleep via Fuzzy Kernel Measures of Information Dynamics

Apnea and other breathing-related disorders have been linked to the development of hypertension or impairments of the cardiovascular, cognitive or metabolic systems. The combined assessment of multiple physiological signals acquired during sleep is of fundamental importance for providing additional insights about breathing disorder events and the associated impairments. In this work, we apply information-theoretic measures to describe the joint dynamics of cardiorespiratory physiological processes in a large group of patients reporting repeated episodes of hypopneas, apneas (central, obstructive, mixed) and respiratory effort related arousals (RERAs). We analyze the heart period as the target process and the airflow amplitude as the driver, computing the predictive information, the information storage, the information transfer, the internal information and the cross information, using a fuzzy kernel entropy estimator. The analyses were performed comparing the information measures among segments during, immediately before and after the respiratory event and with control segments. Results highlight a general tendency to decrease of predictive information and information storage of heart period, as well as of cross information and information transfer from respiration to heart period, during the breathing disordered events. The information-theoretic measures also vary according to the breathing disorder, and significant changes of information transfer can be detected during RERAs, suggesting that the latter could represent a risk factor for developing cardiovascular diseases. These findings reflect the impact of different sleep breathing disorders on respiratory sinus arrhythmia, suggesting overall higher complexity of the cardiac dynamics and weaker cardiorespiratory interactions which may have physiological and clinical relevance.

Shifting and reducing breathing disturbance in patients with very severe obstructive sleep apnea by modified Z-palatoplasty with one-layer closure in one-stage multilevel surgery

Very severe obstructive sleep apnea (OSA) with apnea-hypopnea index (AHI) ≥ 60 events/h differs in several areas from OSA with other severities, including having a low-level daytime partial pressure of oxygen and residual on-CPAP (continuous positive airway pressure) AHIs greater than 20/h. Patients with very severe OSA show narrow retroglossal space and confined framework, which is difficult to be enlarged via conventional Uvulopalatopharyngoplasty (UPPP) surgery, resulting in poor response to non-framework surgeries. Our latest report showed efficacy and efficiency for subjects undergoing modified Z-palatoplasty (ZPP) with one-layer closure in a one-stage multilevel surgery. It is unclear whether and how this procedure could help patients with very severe OSA characterized with confined framework. From Mar. 2015 to May 2018, we enrolled 12 patients with very severe OSA receiving one-stage multi-level surgery with modified ZPP with one-layer closure, CO2 laser partial tongue-base glossectomy, and bilateral septomeatoplasty. Our results show that the surgery reduced AHI from 73.8 ± 10.7 to 30.8 ± 23.2 events/h and achieved a mean AHI reduction of 58.3% (p < 0.001 against 0 reduction or no surgery). The surgery shifted components of the breathing disturbances. It reduced more apnea than hypopnea and might convert some apnea to hypopnea.

Risk factors associated with nocturia in patients with obstructive sleep apnea syndrome

AIM

To evaluate the risk factors associated with nocturia in patients with obstructive sleep apnea syndrome (OSAS).

MATERIALS AND METHODS

Patients aged over 18 years who had been diagnosed with OSAS using polysomnography (PSG) from January to December 2019 were evaluated. The number of nocturia episodes had been assessed in a 3-day bladder diary. We analysed the age, sex, body mass index (BMI) score, apnea-hypopn ea index (AHI) score and severity, hypertension, diabetes mellitus, smoking and heart diseases in all patients.

RESULTS

A total of 124 patients with a mean age of 49.9 ± 11.6 years (range: 25-81 years) were included in the study. Ninety-two (75.8%) patients had nocturia. The mean number of nocturia episodes of patients with nocturia was 2.4 ± 1.3. To determine factors affecting the risk of nocturia, the logistic regression analysis was performed. Patient age and BMI scores were found as the most effective risk factors determining nocturia (P < .05). The odds of patient age were 1.06 (odds ratio: 1.12; 95% confidence interval: 1.01-1.11; P = .010) times higher for patients with nocturia. Every 1-unit increase in the BMI score increased the risk of nocturia 1.12 times. In the study period, 48 patients with nocturia had undergone the continuous positive airway pressure (CPAP) therapy or surgical treatment. The mean number of nocturia episodes of these patients was 2.3 ± 1.4 before treatment and 1.7 ± 2.2 after treatment, showing a significant decrease (P = .032). Although the total daily urine volume increased significantly with the treatment, the total night-time urine volume decreased significantly at night (P = .016 and P = .024, respectively).

CONCLUSION

The age and BMI score were the risk factors associated with nocturia in patients with OSAS.

Effects of continuous positive airway pressure on plasma fibrinogen levels in obstructive sleep apnea patients: a systemic review and meta-analysis

OBJECTIVE

Fibrinogen has been implicated to play a role in the pathophysiology of obstructive sleep apnea (OSA). Many studies have evaluated the effect of continuous positive airway pressure (CPAP) on plasma fibrinogen levels in OSA patients. However, results from different reports were not consistent. To assess the effect of CPAP treatment on plasma fibrinogen levels of patients with OSA, a meta-analysis was performed.

METHODS

A systematic search of Pubmed, Embase, Cochrane, Wanfang Database and Chinese National Knowledge Infrastructure was performed. Data were extracted, and then weighted mean difference (WMD) and 95% confidence intervals (CIs) were calculated using a random-effects model.

RESULTS

Twenty-two studies involving 859 patients were included in this meta-analysis. Combined data showed that plasma fibrinogen concentrations decreased after CPAP therapy (WMD = -0.38 g/l, 95% CI [-0.54 to -0.22 g/l], P<0.001). In the subgroup analyses by therapy duration, plasma fibrinogen concentrations declined significantly in the long-term (≥1 month) CPAP therapy subgroup (WMD = -0.33 g/l, 95% CI [-0.49 to -0.16 g/l], P<0.001) but not in the short-term (<1 month) CPAP therapy subgroup (WMD = -0.84 g/l, 95% CI [-1.70 to 0.03 g/l], P=0.058). Moreover, in patients with long-term CPAP therapy duration, plasma fibrinogen levels decreased with good CPAP compliance (≥4 h/night) (WMD = -0.37 g/l, 95% CI [-0.55 to -0.19 g/l], P<0.001) but not with poor CPAP compliance (<4 h/night) (WMD = 0.12 g/l, 95% CI [-0.09 to 0.33 g/l], P=0.247).

CONCLUSION

Long-term CPAP treatment with good compliance can reduce the plasma fibrinogen levels in patients with OSA.

Analyzing Neck Circumference as an Indicator of CPAP Treatment Response in Obstructive Sleep Apnea with Network Medicine

We explored the relationship between obstructive sleep apnea (OSA) patients' anthropometric measures and the CPAP treatment response. To that end, we processed three non-overlapping cohorts (D1, D2, D3) with 1046 patients from four sleep laboratories in Western Romania, including 145 subjects (D1) with one-night CPAP therapy. Using D1 data, we created a CPAP-response network of patients, and found neck circumference (NC) as the most significant qualitative indicator for apnea-hypopnea index (AHI) improvement. We also investigated a quantitative NC cutoff value for OSA screening on cohorts D2 (OSA-diagnosed) and D3 (control), using the area under the curve. As such, we confirmed the correlation between NC and AHI (ρ=0.35, p<0.001) and showed that 71% of diagnosed male subjects had bigger NC values than subjects with no OSA (area under the curve is 0.71, with 95% CI 0.63-0.79, p<0.001); the optimal NC cutoff is 41 cm, with a sensitivity of 0.8099, a specificity of 0.5185, positive predicted value (PPV) = 0.9588, negative predicted value (NPV) = 0.1647, and positive likelihood ratio (LR+) = 1.68. Our NC =41 cm threshold classified the D1 patients' CPAP responses-measured as the difference in AHI prior to and after the one-night use of CPAP-with a sensitivity of 0.913 and a specificity of 0.859.

A Non-Framework Multilevel Surgery May Reduce Mean Heart Rate in Patients with Very Severe Obstructive Apnea Having Confined Retroglossal Space and Framework

An elevated mean heart rate in untreated patients of obstructive sleep apnea (OSA) may lead to a higher risk of mortality and the development of various cardiovascular diseases. The elevation may positively relate to the severity of OSA and present in both wakefulness and sleep. A reduction in heart rate has been presented in reports of treating OSA patients with continuous positive airway pressure (CPAP). However, patients with very severe OSA may refuse use of CPAP devices and advocated surgeries, such as direct skeletal surgery or tracheostomy. It is unclear whether the non-framework multilevel surgery we reported previously can overcome the unfavorable anatomy and reduce mean heart rate, which serves as a risk factor of mortality. Here, we show that multilevel surgery reduced the mean heart rate from 68.6 to 62.7 with a mean reduction of 5.9 beats/min. The results suggest that the surgery may reduce the risk of consequences and mortality associated with an elevated mean heart rate, such as various cardiovascular diseases. We disclose these findings, along with the variations and possible risks to our future patients with very severe OSA who refuse or cannot use a CPAP device or reject direct skeletal surgery.

An Overview of the Pathophysiology of Metabolic Changes and Their Sequence of Occurrence in Obese Diabetic Females: A Narrative Review

Obesity and diabetes both mediate their effects through insulin resistance and frequently co-exist. Insulin resistance is one of the key factors in the development of the metabolic syndrome. Adult females tend to develop obesity more frequently than males. One of the factors causing this difference is the pattern of changes that occur as females age from pre-menopausal to the post-menopausal stage, causing a change in the pattern of accumulation of fats. Several studies have explored and described the association between obesity and metabolic syndrome and their effect on type II diabetes. We conducted our literature search using PubMed and Google Scholar as our primary databases. We selected a total of 49 articles for review after applying the inclusion and exclusion criteria and removing the duplicate articles. We chose the full-text articles that were published in the English language only. The selected studies were randomized controlled trials and review papers. The reviewed articles showed that visceral fat, central obesity, and fasting blood sugar of post-menopausal is higher than in pre-menopausal women and needs adequate management. More studies are needed in the future to explore the patterns of the metabolic changes in obese females to provide early and better management of diabetes and prevent related complications.

How to manage continuous positive airway pressure (CPAP) failure -hybrid surgery and integrated treatment

Obstructive sleep apnea (OSA) is a prevalent disease, which influences social relations and quality of life with major health impact. The etiology of OSA is multi-factorial involving both anatomical obstruction and physiological collapse of the upper airway during sleep with different proportion in individual patients. Continuous positive airway pressure (CPAP) is the gold standard and first-line treatment for OSA patients. The mechanism of CPAP is acting as air splint to avoid principal pharyngeal collapse during sleep. Consequently, extrapharyngeal collapse and significant pharyngeal obstructions can lower its compliance and lead to its failure. Adequate mask and pressure with thorough survey to eliminate side effects of CPAP from nasal, mask and flow-related problems are the prerequisite to improve CPAP compliance. For CPAP failure patients, multi-dimensional surgery is an alternative and salvage treatment that involves soft tissue surgery, skeletal surgery, and bariatric surgery. OSA patients with craniofacial anomaly are suggested to skeletal surgery. By contrast, OSA patients with pathological obesity are referred to bariatric surgery. Soft tissue surgery targets at the nose, soft palate, lateral pharyngeal wall, tongue and epiglottis that can be implemented by multi-level surgery with hybrid technique (mucosa-preservation, fat-ablation, muscle-suspension, tonsil-excision, cartilage-reconstruction) to maximize surgical outcomes and minimize complications. Some evolution in surgical concept and technique are noteworthy that include mini-invasive septoturbinoplasty, palatal suspension instead of excision, whole tongue treatment, and two-dimensional supraglottoplasty. Postoperative integrated treatment including myofunctional, positional therapy and body weight control reduces relapse of OSA and improves long-term treatment outcomes.

Obstructive sleep apnea intensifies stroke severity following middle cerebral artery occlusion

STUDY OBJECTIVES

Obstructive sleep apnea (OSA) is a sleep disorder caused by transient obstruction of the upper airway and results in intermittent hypoxia, sleep fragmentation, sympathetic nervous system activation, and arousal which can have an adverse effect on cardiovascular disease. It is theorized that OSA might intensify stroke injury. Our goal here was to develop a new model of experimental OSA and test its ability to aggravate behavioral and morphological outcomes following transient brain ischemia/reperfusion.

METHODS

We used a 3D printed OSA device to expose C57BL6 mice to 3 h of OSA (obstructive apnea index of 20 events per hour) for three days. These mice were then subjected to ischemia/reperfusion using the middle cerebral artery occlusion model (MCAO) stroke and examined for overall survival, infarct size and neurological scoring.

RESULTS

We found that OSA transiently decreased respiration and reduced oxygen saturation with bradycardia and tachycardia typical of human responses during apneic events. Brain injury from MCAO was significantly increased by OSA as measured by infarct size and location as well as by intensification of neurological deficits; mortality following MCAO was also increased in OSA animals.

CONCLUSIONS

Our findings suggest that our new model of OSA alters respiratory and cardiovascular physiological functions and is associated with enhanced ischemia/reperfusion mediated injury in our non-invasive, OSA intensified model of stroke.

Analysis of oral microbiota in patients with obstructive sleep apnea-associated hypertension

Obstructive sleep apnea-hypopnea syndrome (OSAHS) is an independent risk factor for hypertension (HTN). The oral microbiota plays a pathophysiological role in cardiovascular diseases; however, there are few reports directly investigating and identifying the organisms involved in OSAHS-related HTN. Therefore, this study aimed to identify those organisms. We obtained 139 oral samples and determined the microbiome composition using pyrosequencing and bioinformatic analyses of the 16S rRNA. We examined the fasting levels of cytokines and homocysteine in all participants and analyzed the correlations between the oral microbiota and homocysteine levels. We determined the molecular mechanism underlying HTN by investigating the genetic composition of the strains in the blood. We detected higher relative abundances of Porphyromonas and Aggregatibacter and elevated proinflammatory cytokines in patients with OSAHS of varying severity compared with individuals without OSAHS; however, the two organisms were not measured in the blood samples from all participants. High levels of specific Porphyromonas bacteria were detected in patients with OSAHS with and without HTN, whereas the relative abundance of Aggregatibacter was negatively correlated with the homocysteine level. The receiver operating characteristic curve analysis of controls and patients with OSAHS resulted in area under the curve values of 0.759 and 0.641 for patients with OSAHS with or without HTN, respectively. We found that the predictive function of oral microbiota was different in patients with OSAHS with and without HTN. However, there was no direct invasion by the two organisms causing endothelial cell injury, leading to speculation regarding the other mechanisms that may lead to HTN. Elucidating the differences in the oral microbiome will help us understand the pathogenesis of OSAHS-related HTN.

The Clinical Value of N-Terminal Pro B-Type Natriuretic Peptide in Evaluating Obstructive Sleep Apnea in Patients With Coronary Artery Disease

STUDY OBJECTIVES

Natriuretic peptides have been identified as biomarkers of increased myocardial wall stress in the context of obstructive sleep apnea (OSA) in the general population. However, the relationship between N-terminal pro B-type natriuretic peptide (NT-proBNP) and OSA remains unclear in patients with coronary artery disease (CAD). Hence, we aimed to investigate the clinical value of NT-proBNP in evaluating OSA in a large population of patients with CAD.

METHODS

Consecutive patients with CAD were prospectively enrolled between February 2015 and March 2018. Portable respiratory monitoring was applied to facilitate the diagnosis of sleep apnea. Patients were as assigned to the non-OSA (when the respiratory events index [REI] or 3% oxygen desaturation index [ODI] < 15 events/h) and OSA (when the REI or 3% ODI ≥ 15 events/h) groups. Multivariate analyses were used to explore the independent association between NT-proBNP levels and OSA.

RESULTS

A total of 1,292 consecutive patients were included with a mean NT-proBNP value of 826.57 μg/L. Patients with high levels of NT-proBNP experienced increasing severity of OSA in those with CAD (P = .0004). Univariate analysis demonstrated that NT-proBNP was a risk factor for OSA (odds ratio [OR] 1.10, 95% confidence interval [CI] 1.03-1.18, P = .005). In addition, multivariate analysis revealed that NT-proBNP was independently associated with the presence of OSA (OR 1.11, 95% CI 1.02-1.20, P = .012) even after adjusting for other cofounding factors.

CONCLUSIONS

Elevated levels of NT-proBNP were independently associated with a higher likelihood of OSA in patients with CAD. Periodically screening for NT-proBNP levels may provide early identification of OSA.

Unique sleep-stage transitions determined by obstructive sleep apnea severity, age and gender

In obstructive sleep apnea, patients' sleep is fragmented leading to excessive daytime sleepiness and co-morbidities like arterial hypertension. However, traditional metrics are not always directly correlated with daytime sleepiness, and the association between traditional sleep quality metrics like sleep duration and arterial hypertension is still ambiguous. In a development cohort, we analysed hypnograms from mild (n = 209), moderate (n = 222) and severe (n = 272) obstructive sleep apnea patients as well as healthy controls (n = 105) from the European Sleep Apnea Database. We assessed sleep by the analysis of two-step transitions depending on obstructive sleep apnea severity and anthropometric factors. Two-step transition patterns were examined for an association to arterial hypertension or daytime sleepiness. We also tested cumulative distributions of wake as well as sleep-states for power-laws (exponent α) and exponential distributions (decay time τ) in dependency on obstructive sleep apnea severity and potential confounders. Independent of obstructive sleep apnea severity and potential confounders, wake-state durations followed a power-law distribution, while sleep-state durations were characterized by an exponential distribution. Sleep-stage transitions are influenced by obstructive sleep apnea severity, age and gender. N2 → N3 → wake transitions were associated with high diastolic blood pressure. We observed higher frequencies of alternating (symmetric) patterns (e.g. N2 → N1 → N2, N2 → wake → N2) in sleepy patients both in the development cohort and in a validation cohort (n = 425). In conclusion, effects of obstructive sleep apnea severity and potential confounders on sleep architecture are small, but transition patterns still link sleep fragmentation directly to obstructive sleep apnea-related clinical outcomes like arterial hypertension and daytime sleepiness.

MicroRNA expression profile is altered in the upper airway skeletal muscle tissue of patients with obstructive sleep apnea-hypopnea syndrome

Objective

To investigate the involvement of microRNAs (miRNAs) in the pathogenesis of obstructive sleep apnea-hypopnea syndrome (OSAHS).

Methods

In this study, we investigated miRNA profiles in the upper airway (UA) skeletal muscles of four patients with OSAHS and four matched controls using the miRCURY miRNA array. In another cohort of 12 OSAHS cases and 7 controls, the mRNA expression levels of interleukin (IL)-6 and Lin-28 homolog A (Lin28A), targets of the downregulated let-7 family members, were measured by real-time quantitative-PCR. The potential targets of the miRNAs were predicted by miRNA target prediction databases miRanda, Microcosm, and Targetscan.

Results

The array identified 370 differentially expressed miRNAs, of which 181 were upregulated and 189 were downregulated in OSAHS patients (based on a fold-change >2.0 and p < 0.05). Upregulation of IL-6 and Lin28A was validated by quantitative reverse transcription PCR. The 612 targets predicted by all three algorithms were subjected to gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses. The results revealed perturbations in signaling pathways and cellular functions.

Conclusion

This study demonstrated profoundly altered miRNA expression profiles in upper airway muscular tissues of patients with OSAHS, which might contribute to the formation and development of OSAHS.

Obstructive Sleep Apnea and Hypertension: Why Treatment Does Not Consistently Improve Blood Pressure

PURPOSE OF REVIEW

Obstructive sleep apnea (OSA) and hypertension are two phenomena deeply linked together and, although a causal relationship has been suggested, a recent meta-analysis showed only a very modest effect of OSA treatment on blood pressure (BP). However, a vast number of randomized controlled trials published so far share some limitations, mainly of methodological nature: neither OSA nor BP is always assessed in a standardized way. Moreover, compliance with OSA treatment is often sub-optimal making the results of these trials difficult to interpret.

RECENT FINDINGS

Recent studies have shown that antihypertensive drugs can reduce BP more than OSA treatment, showing a better compliance profile and very few side effects. Considering the importance of reducing the overall cardiovascular risk of OSA patients, a more careful management of patient's antihypertensive medication could allow a better BP control also in this condition. In addition, greater efforts should be made to improve patient's acceptance of OSA treatment with the aim of improving their compliance.

Effects of aerobic exercise training on the risk factors for liver diseases in elderly women with obesity and impaired fasting glucose: A pilot study

[Purpose]

In the present pilot study, we aimed to investigate the effects of the Silverrobics exercise program, which is similar to aerobic dance, on the factors related to glucose metabolism and liver enzymes.

[Methods]

Eight elderly women with obesity and impaired fasting glucose participated in the Silverrobics exercise program (60 minutes per session for five times a week for 8 weeks). The program was conducted at 50–60% of the heart rate reserve at 1 to 2 weeks and at 60–80% of the heart rate reserve at 3 to 8 weeks. To verify the effect of this 8-week exercise program on glucose metabolism and liver enzymes, blood analysis at pre- and post-training was performed.

[Results]

After the Silverrobics exercise program, there were significant decreases in the glucose (p<0.05), glycated hemoglobin A1c (p<0.05), 1,5-anhydroglucitol (p<0.05), and insulin levels (p<0.01) and homeostatic model assessment of insulin resistance score (p<0.05). However, there were no significant effects on the liver enzymes, except for alkaline phosphatase. The alkaline phosphatase level increased after the Silverrobics exercise program (p<0.05).

[Conclusion]

Although the Silverrobics exercise program had no beneficial effects on the liver enzymes, it may play an important role in preventing liver diseases considering the effects on glucose metabolism.

Sleep apnea: Do not forget to inspect the throat!

Obstructive sleep apnea syndrome (OSAS) is a widespread and underdiagnosed disease. Causes are mostly related to obesity and anatomy with oro-pharyngeal narrowing. Parapharyngeal tumors are rare but can easily be treated. Careful oro-pharyngeal examination in OSAS patient is cheap, easy to perform by non-ENT specialists, quick, and avoids inadequate treatment.

The correlation between obstructive sleep apnea and diabetic neuropathy: A meta-analysis

BACKGROUND

The aim of this study was to explore the correlation between obstructive sleep apnea (OSA) and diabetic neuropathy.

MATERIALS AND METHODS

After working out searching strategy, literatures were screened from the electronic databases: PubMed, Embase, and the Cochrane library. R 3.12 was utilized to perform meta-analysis, and odds ratio (OR) and its 95% confidence interval (CI) were used to present effect size. Heterogeneity was assessed by χ²-based Q test and I² statistics. Publication bias was estimated by Egger's test and sensitivity was evaluated by leave one out methods.

RESULTS

According to the criteria, a total of 11 studies with 1842 patients were enrolled in this study. With a significant heterogeneity (Q=31.83, I²=68.60%), the random effects model was utilized to assess the effect size of pooled data. A remarkable correlation was identified OSA and diabetic neuropathy (OR=1.84, 95% CI: 1.18-2.87) without publication bias (t=1.68, P=0.13). Meanwhile, the result of leave one out performed a well sensitivity. Moreover, the subgroup analyses presented that OSA was significantly correlated with type 1 diabetic neuropathy (OR=1.97, 95% CI: 1.19-3.25), but no remarkable correlation was identified between OSA and type 1 (OR=1.84, 95% CI: 0.86-3.93) or 1+2 (OR=1.30, 95% CI: 0.43-3.92) diabetic neuropathy.

CONCLUSION

OSA was significantly correlated with neuropathy in type 1 diabetes, but not in type 2 and type 1+2 diabetes.

Brief Review: Ergospirometry in Patients with Obstructive Sleep Apnea Syndrome

This brief review summarizes the available literature on the intersection of obstructive sleep apnea syndrome (OSAS) and ergospirometry. Ergospirometry provides an assessment of integrative exercise responses involving pulmonary, cardiovascular, neuropsychological, and skeletal muscle systems, which are not adequately reflected through the measurement of individual organ system functions. Sleep disorders, including OSAS, often exacerbate problems in the operation of the autonomic nervous system, heart function, lung mechanics, anxiety, and muscle metabolism. Patients with OSAS have low aerobic capacity due to dysfunction of these systems, which often affect quality of sleep. Further research is necessary to elucidate the precise mechanisms through which ergospirometry can be useful in the assessment and early identification of patients with OSAS.

Elevated Oxidative Stress and Inflammation in Hypothalamic Paraventricular Nucleus Are Associated With Sympathetic Excitation and Hypertension in Rats Exposed to Chronic Intermittent Hypoxia

Obstructive sleep apnea (OSA), characterized by recurrent collapse of the upper airway during sleep leading to chronic intermittent hypoxia (CIH), is an independent risk factor for hypertension. Sympathetic excitation has been shown to play a major role in the pathogenesis of OSA-associated hypertension. Accumulating evidence indicates that oxidative stress and inflammation in the hypothalamic paraventricular nucleus (PVN), a critical cardiovascular and autonomic center, mediate sympathetic excitation in many cardiovascular diseases. Here we tested the hypothesis that CIH elevates oxidative stress and inflammation in the PVN, which might be associated with sympathetic excitation and increased blood pressure in a rat model of CIH that mimics the oxygen profile in patients with OSA. Sprague-Dawley rats were pretreated with intracerebroventricular (ICV) infusion of vehicle or superoxide scavenger tempol, and then exposed to control or CIH for 7 days. Compared with control+vehicle rats, CIH+vehicle rats exhibited increased blood pressure, and increased sympathetic drive as indicated by the blood pressure response to ganglionic blockade and plasma norepinephrine levels. Pretreatment with ICV tempol prevented CIH-induced increases in blood pressure and sympathetic drive. Molecular studies revealed that expression of NAD(P)H oxidase subunits, production of reactive oxygen species, expression of proinflammatory cytokines and neuronal excitation in the PVN were elevated in CIH+vehicle rats, compared with control+vehicle rats, but were normalized or reduced in CIH rat pretreated with ICV tempol. Notably, CIH+vehicle rats also had increased systemic oxidative stress and inflammation, which were not altered by ICV tempol. The results suggest that CIH induces elevated oxidative stress and inflammation in the PVN, which lead to PVN neuronal excitation and are associated with sympathetic excitation and increased blood pressure. Central oxidative stress and inflammation may be novel targets for the prevention and treatment of hypertension in patients with OSA.

The effects of obesity on pulmonary function in children

The prevalence of obesity has risen rapidly in the United States in the past 20 years. Up to 25% of US children are obese, and obesity can be directly correlated with immediate and long-term health consequences. Pediatric obesity can harm multiple body systems and is a public health issue. This article focuses on how obesity affects a child's respiratory system, including pulmonary function, exercise intolerance, gas exchange, and airway musculature.

Contribution of TLR4 signaling in intermittent hypoxia-mediated atherosclerosis progression

Background

Intermittent hypoxia (IH), a typical character of obstructive sleep apnea (OSA), is related to atherogenesis. However, the role of IH on atherosclerosis (AS) progression and the mechanisms involved remains poorly understood.

Methods

In the present study, high-fat fed ApoE^−/− mice were treated with recombinant shRNA-TLR4 lentivirus and exposed to IH. Atherosclerotic lesions on the en face aorta and cross-sections of aortic root were examined by Oil-Red O staining. The content of lipids and collagen of aortic root plaques were detected by Oil-Red O staining and Sirius red staining, respectively. The TLR4, NF-κB p65, α-SMA and MOMA-2 expression in aorta and IL-6 and TNF-α expression in the mice serum were also detected.

Results

Compared with the Sham group, the IH treated group further increased atherosclerotic plaque loads and plaque vulnerability in the aortic sinus. Along with increased TLR4 expression, enhanced NF-κB activation, inflammatory activity and aggravated dyslipidemia were observed in the IH treated group. TLR4 interference partly inhibited IH-mediated AS progression with decreased inflammation and improved cholesterol levels. Similarly, in endothelial cells, hypoxia/reoxygenation exposure has been shown to promote TLR4 expression and activation of proinflammatory TLR4/NF-κB signaling, while TLR4 interference inhibited these effects.

Conclusions

We found that the IH accelerated growth and vulnerability of atherosclerotic plaque, which probably acted by triggering the activation of proinflammatory TLR4/NF-κB signaling. These findings may suggest that IH is a risk factor for vulnerable plaque and provide a new insight into the treatment of OSA-induced AS progression.

Angiotensin converting enzyme 1 in the median preoptic nucleus contributes to chronic intermittent hypoxia hypertension

Obstructive sleep apnea is associated with hypertension and cardiovascular disease. Chronic intermittent hypoxia is used to model the arterial hypoxemia seen in sleep apnea patients and is associated with increased sympathetic nerve activity and a sustained diurnal increase in blood pressure. The renin angiotensin system has been associated with hypertension seen in chronic intermittent hypoxia. Angiotensin converting enzyme 1, which cleaves angiotensin I to the active counterpart angiotensin II, is present within the central nervous system and has been shown to be regulated by AP‐1 transcription factors, such as ΔFosB. Our previous study suggested that this transcriptional regulation in the median preoptic nucleus contributes to the sustained blood pressure seen following chronic intermittent hypoxia. Viral mediated delivery of a short hairpin RNA against angiotensin converting enzyme 1 in the median preoptic nucleus was used along with radio‐telemetry measurements of blood pressure to test this hypothesis. FosB immunohistochemistry was utilized in order to assess the effects of angiotensin converting enzyme 1 knockdown on the activity of nuclei downstream from median preoptic nucleus. Angiotensin converting enzyme 1 knockdown within median preoptic nucleus significantly attenuated the sustained hypertension seen in chronic intermittent hypoxia. Angiotensin converting enzyme 1 seems to be partly responsible for regulating downstream regions involved in sympathetic and blood pressure control, such as the paraventricular nucleus and the rostral ventrolateral medulla. The data suggest that angiotensin converting enzyme 1 within median preoptic nucleus plays a critical role in the sustained hypertension seen in chronic intermittent hypoxia.

Obstructive Sleep Apnea-Induced Hypertension: Role of the Gut Microbiota

PURPOSE OF REVIEW

Obstructive sleep apnea (OSA) is a significant risk factor for systemic hypertension and other cardiovascular diseases. While this relationship has been firmly established, a detailed understanding of how OSA leads to hypertension is lacking. This review will examine the emerging idea that the gut microbiota plays a role in the development of hypertension, including that associated with OSA.

RECENT FINDINGS

Disruption of the normal composition of the gut microbiota, termed dysbiosis, has been identified in a number of metabolic and cardiovascular diseases, including diabetes, obesity, and atherosclerosis. Recently, a number of studies have demonstrated gut dysbiosis in various animal models of hypertension as well as in hypertensive patients. Evidence is now emerging that gut dysbiosis plays a causal role in the development of OSA-induced hypertension. In this review, we will examine the evidence that gut dysbiosis plays a role in OSA-induced hypertension. We will discuss potential mechanisms linking OSA to gut dysbiosis, examine how gut dysbiosis may be linked to hypertension, and highlight how this understanding may be utilized for the development of future therapeutics.

Relationship between heart rate excursion and apnea duration in patients with Obstructive Sleep Apnea

Obstructive Sleep Apnea (OSA) is a sleep disorder with a high prevalence in the general population. It is a risk factor for many cardiovascular diseases, and an independent risk factor for cerebrovascular diseases such as stroke. After an apnea episode, both arterial blood pressure and cerebral blood flow velocity change in function of the apnea duration (AD). We hypothesized that the relative excursion in heart rate (AHR), defined as the percentage difference between the maximum and the minimum heart rate values associated to an obstructive apnea event, is also related to AD. In this work we studied the relationship between apnea-related AHR and AD in a population of eight patients with severe OSA. AHR and AD showed a moderate but statistically significant correlation (p <; 0.0001) in a total of 1454 obstructive apneas analyzed. The average heart rate excursion for apneas with AD ≥ 30s (ΔHR = 31.29 ± 6.64%) was significantly greater (p = 0.0002) than for apneas with AD ∈ [10,20)s (ΔHR = 18.14±3.08%). We also observed that patients with similar Apnea-Hypopnea Index (AHI) may exhibit remarkably different distributions of AHR and AD, and that patients with a high AHI need not have a higher average AHR than others with a lower severity index. We conclude that the overall apnea-induced heart rate excursion is partially explained by the duration of apnoeic episodes, and it may be a simple measure of the cardiovascular stress associated with OSA that is not directly reflected in the AHI.

Association between Snoring and High-Risk Carotid Plaque Features

Objectives Previous studies have demonstrated an association between snoring and carotid disease independent of sleep apnea. The aim of this study was to quantify the association between self-reported snoring and high-risk carotid plaque features on magnetic resonance imaging (MRI) that predict stroke. Study Design Cross-sectional. Setting Tertiary care university hospital and affiliated county hospital. Methods We surveyed 133 subjects with asymptomatic carotid artery disease that had been previously evaluated with high-resolution MRI. The survey captured data on self-reported snoring (exposure) and covariates (age, sex, body mass index, and sleep apnea via the STOP-Bang questionnaire). A subset of patients underwent home sleep apnea testing. High-risk carotid plaque features were identified on the high-resolution MRI and included thin/ruptured fibrous cap and intraplaque hemorrhage (outcomes). We quantified the association between snoring and high-risk carotid plaque features with the chi-square test (unadjusted analysis) and multivariate logistic regression adjusting for the covariates. Results Of 133 subjects surveyed, 61 (46%) responded; 32 (52%) reported snoring. Significantly higher proportions of snorers than nonsnorers had a thin/ruptured fibrous cap (56% vs 25%, P = .01) and intraplaque hemorrhage (63% vs 29%, P < .01). In multivariate analysis, snoring was associated with thin/ruptured fibrous cap (odds ratio, 4.4; 95% CI, 1.1-16.6; P = .04) and intraplaque hemorrhage (odds ratio, 8.2; 95% CI, 2.1-31.6; P < .01) after adjusting for age, sex, body mass index, and sleep apnea. Conclusion This pilot study suggests a significant independent association between snoring and high-risk carotid plaque features on MRI. Further study is warranted to confirm these results in a larger cohort of subjects.

Obstructive sleep apnoea and right ventricular function: A combined assessment by speckle tracking and three-dimensional echocardiography

BACKGROUND

Little is known on right ventricular (RV) involvement in obstructive sleep apnoea (OSA). This study aimed at evaluating early RV dysfunction by standard and advanced echocardiography in OSA.

METHODS

Fifty-nine OSA patients without heart failure and 29 age-matched controls underwent standard, speckle tracking and real time 3D echocardiography of right ventricle. OSA patients performed lung function tests and overnight cardio-respiratory monitoring with evaluation of apnea-hypopnea index (AHI).

RESULTS

OSA had significantly higher body mass index and systolic blood pressure (BP) than controls. RV diameters and systolic pulmonary arterial pressure (sPAP) were significantly higher in OSA, in presence of comparable tricuspid annular plane systolic excursion (TAPSE). OSA showed marginally lower RV global longitudinal strain (GLS) (p<0.05) and RV lateral wall strain (RV LLS) (p=0.04). Three-dimensional RV ejection fraction did not differ between the two groups. By stratifying patients according to sPAP, 18 OSA patients with sPAP≥30mmHg had lower TAPSE (p<0.05), RV GLS and RV LLS (both p<0.001) than 37 patients with normal sPAP. By separate multivariate analyses, RV GLS and RV LLS were independently associated with sPAP (both p<0.0001), AHI (p=0.035 and p=0.015 respectively) and BMI (p<0.05 and p=0.034) but not with age and systolic BP in OSA.

CONCLUSIONS

A subclinical RV dysfunction is detectable by speckle tracking in OSA. The impairment of RV GLS and RV LLS is more prominent than that of TAPSE and is evident when RVEF is still normal. GLS is independently associated with sPAP and OSA severity.

Obstructive Sleep Apnea-Induced Hypertension: Role of the Gut Microbiota

PURPOSE OF REVIEW

Obstructive sleep apnea (OSA) is a significant risk factor for systemic hypertension and other cardiovascular diseases. While this relationship has been firmly established, a detailed understanding of how OSA leads to hypertension is lacking. This review will examine the emerging idea that the gut microbiota plays a role in the development of hypertension, including that associated with OSA.

RECENT FINDINGS

Disruption of the normal composition of the gut microbiota, termed dysbiosis, has been identified in a number of metabolic and cardiovascular diseases, including diabetes, obesity, and atherosclerosis. Recently, a number of studies have demonstrated gut dysbiosis in various animal models of hypertension as well as in hypertensive patients. Evidence is now emerging that gut dysbiosis plays a causal role in the development of OSA-induced hypertension. In this review, we will examine the evidence that gut dysbiosis plays a role in OSA-induced hypertension. We will discuss potential mechanisms linking OSA to gut dysbiosis, examine how gut dysbiosis may be linked to hypertension, and highlight how this understanding may be utilized for the development of future therapeutics.

Circadian rhythms in blood pressure, heart rate, hormones, and on polysomnographic parameters in severe obstructive sleep apnea syndrome patients: effect of continuous positive airway pressure

INTRODUCTION

Seventeen male patients with severe obstructive sleep apnea syndrome (OSAS; apnea-hypopnea index>30/h) were monitored by polysomnography in the sleep lab before and after about 8 weeks of continuous positive airway pressure (CPAP). Twelve of the patients were hypertensive, but treated by antihypertensive drugs. The circadian rhythms in blood pressure (BP) and heart rate were determined by ambulatory BP monitoring and motor activity was monitored by a motion logger. As the sympathetic tone is reported to be increased in sleep apnea, the circadian rhythm in plasma norepinephrine was studied in parallel and as a marker rhythm of the biological clock plasma melatonin was determined around the clock by radioimmunoassay.

RESULTS

Level and rhythm in BP and heart rate were not significantly affected by CPAP in this group of patients, but the number of dippers increased after CPAP intervention. The high 24 h plasma values of norepinephrine were lowered by CPAP therapy. In contrast, melatonin values were disturbed in OSAS patients with a loss in nocturnal increase; this pattern was not corrected by CPAP. Sleep functions (deep sleep, slow wave sleep, rapid eye movement sleep, arousal index, apnea-hypopnea index, desaturation index) were disturbed in OSAS patients as monitored by polysomnography and were significantly improved by CPAP therapy.

CONCLUSION

The study indicates that BP-controlled hypertensive patients with OSAS can additionally benefit from CPAP therapy by increasing the number of dippers. This treatment significantly improved sleep functions and OSAS symptoms. In addition, arousal movements at night were also reduced and the high sympathetic tone during early morning hours was also decreased. However, there is still an indication of a disturbed function of the biological clock as the loss in the rhythm in plasma melatonin was not corrected by CPAP.

Role of angiotensin-converting enzyme 1 within the median preoptic nucleus following chronic intermittent hypoxia

Sustained hypertension is an important consequence of obstructive sleep apnea. An animal model of the hypoxemia associated with sleep apnea, chronic intermittent hypoxia (CIH), produces increased sympathetic nerve activity (SNA) and sustained increases in blood pressure. Many mechanisms have been implicated in the hypertension associated with CIH, including the role of ΔFosB within the median preoptic nucleus (MnPO). Also, the renin-angiotensin system (RAS) has been associated with CIH hypertension. We conducted experiments to determine the possible association of FosB/ΔFosB with a RAS component, angiotensin-converting enzyme 1 (ACE1), within the MnPO following 7 days of CIH. Retrograde tract tracing from the paraventricular nucleus (PVN), a downstream region of the MnPO, was used to establish a potential pathway for FosB/ΔFosB activation of MnPO ACE1 neurons. After CIH, ACE1 cells with FosB/ΔFosB expression increased colocalization with a retrograde tracer that was injected unilaterally within the PVN. Also, Western blot examination showed ACE1 protein expression increasing within the MnPO following CIH. Chromatin immunoprecipitation (ChIP) assays demonstrated an increase in FosB/ΔFosB association with the ACE1 gene within the MnPO following CIH. FosB/ΔFosB may transcriptionally target ACE1 within the MnPO following CIH to affect the downstream PVN region, which may influence SNA and blood pressure.

Relationship of galectin-3 with obesity, IL-6, and CRP in women

PURPOSE

To evaluate the association of galectin-3 (Gal3) with obesity and inflammatory status in a cohort of metabolically healthy, predominantly African-American women with varying cardiovascular disease (CVD) risk as determined by CRP levels.

METHODS

We assessed the association between BMI and serum levels of Gal3, IL-6, CRP, and adiponectin in metabolically healthy women (N = 97) to determine the overall association between Gal3, obesity, and inflammation in groups at different CVD risk.

RESULTS

Obese women had significantly higher serum Gal3 compared to non-obese participants (P = 0.0016), although Gal3 levels were comparable among different classes of obesity. BMI (R ² = 0.1406, P = 0.0013), IL-6 (R ² = 0.0689, P = 0.035), and CRP (R ² = 0.0468, P = 0.0419), but not adiponectin, positively predicted the variance of Gal3 levels in the total study population. However, the predicting effect of BMI (R ² = 0.2923, P = 0.0125) and inflammation (R ² = 0.3138, P = 0.038) on Gal3 was only present in women at low/moderate risk of CVD (CRP ≤ 3 µg/mL).

CONCLUSIONS

Gal3 is positively correlated with obesity and inflammation in women, while the presence of elevated CVD risk may disturb the strength of Gal3 as a biomarker of inflammation.