Treatment options for sleep apnoea

Tirzepatide for the treatment of obstructive sleep apnea: Rationale, design, and sample baseline characteristics of the SURMOUNT -OSA phase 3 trial

BACKGROUND

Weight reduction is a standard recommendation for obstructive sleep apnea (OSA) treatment in people with obesity or overweight; however, weight loss can be challenging to achieve and maintain without bariatric surgery. Currently, no approved anti-obesity medication has demonstrated effectiveness in OSA management. This study is evaluating the efficacy and safety of tirzepatide for treatment of moderate to severe OSA in people with obesity.

METHODS

SURMOUNT-OSA, a randomized, placebo -controlled, 52-week phase 3 trial, is investigating the efficacy and safety of tirzepatide for treatment of moderate to severe OSA (apnea hypopnea- index ≥15 events/h) in participants with obesity (body mass index ≥30 kg/m2) and an established OSA diagnosis. SURMOUNT-OSA is made of 2 intervention-specific appendices (ISAs): ISA-1 includes participants with no current OSA treatment, and ISA-2 includes participants using positive airway pressure therapy. Overall, 469 participants have been randomized 1:1 to receive tirzepatide or placebo across the master protocol (ISA-1, n = 234; ISA-2, n = 235). All participants are also receiving lifestyle intervention for weight reduction.

RESULTS

The primary endpoint for the individual ISAs is the difference in apnea hypopnea- index response, as measured by polysomnography, between tirzepatide and placebo arms at week 52. Secondary endpoints include sleep apnea-specific hypoxic burden, functional outcomes, and cardiometabolic biomarkers. The trial employs digital wearables, including home sleep testing to capture time to improvement and accelerometry for daily physical activity assessment, to evaluate exploratory outcomes.

CONCLUSION

SURMOUNT-OSA brings a novel design to investigate if tirzepatide provides clinically meaningful improvement in obesity-related OSA by targeting the underlying etiology.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT05412004.

Decrease of respiratory events in patients with obstructive sleep apnea-hypopnea syndrome using a mandibular advancement device assessed with split night polysomnography

Introduction

Mandibular advancement device (MAD) may represent a feasible choice in the treatment of obstructive sleep apnea-hypopnea syndrome (OSAHS), in well selected patients.

Objective

The aim of this study is to assess the efficacy of MAD in patients with OSAHS, using split night polysomnography (SNP)

Method

We performed an auto controlled clinical trial to assess the efficacy of MAD in 30 patients with snoring and OSAHS. Clinical evaluation was made every 2 weeks to adjust treatment and observe changes in clinical symptoms. Three-months after placement of the MAD, a SNP was performed, using the MAD in the second half of the night, in order to compare the respiratory results.

Results

SNP show significant changes with use of MAD (p<0.05) such as: Decrease in Snore index (from 159.95 to 32.46/h) and in Apnea-hypopnea index (AHI, from 22.45 to 4.63/h), increase in oxygen saturation (SaO₂, from 89.98% to 91.39%) and somnolence improvement, using the Epworth Sleepiness Scale (from 14.4 to 4.6 points).

Conclusion

Our data supports that the use of MAD is an alternative in the management of OSAHS, in well selected patients, used in a multidisciplinary fashion, and evaluated using a SNP.

To treat snoring with nasal steroids - effects on more than one level?

CONCLUSION

An inflammatory swelling in the uvula and nose due to vibration might be a contributing factor in snoring. The presence of corticosteroid receptors in the uvula indicates the possibility for treatment with local steroids. Use of mometasone furoate (MF) for 3 months reduced snoring and related symptoms in some patients.

OBJECTIVE

To investigate the effect of a nasal steroid, MF, on snoring and related discomfort.

SUBJECTS AND METHODS

In the first part of the study, uvular and nasal biopsies from six patients with social snoring were examined using immunohistochemistry to evaluate whether corticosteroid receptors were present. Then 100 snoring patients were invited to participate in the second part of the study. In all, 72 men and 22 women with a mean age of 47 years and BMI 27 answered a questionnaire about symptoms, had ENT status assessed and reported sleep and related variables for a 7 day period. After randomization to placebo or MF, they used a nasal spray for 3 months at a dosage of 200 microg. Thereafter the procedure was repeated.

RESULTS

Corticosteroid receptors were present in the mucous membranes and around the blood vessels in all uvulas examined. A total of 84 patients were evaluated. No decrease in 'mean snoring score' was seen. Daytime sleepiness showed a slight improvement in the MF group and partners were less disturbed. Minor side effects were equal for both groups.

Increasing humidity blocks continuous positive airflow-induced apnea responses in rats

BACKGROUND

The aim of this study was to investigate the role of temperature and humidity in positive continuous pressure flow-induced apnea.

METHODS

Forty-two adult male Sprague-Dawley rats were used in a functionally isolated laryngeal animal model. In study 1, animals were challenged with laryngeal stimulation for 1 minute to detect the possibility of adaptation. In study 2, different airflow conditions (25 degrees C dry-25 degrees C dry, 25 degrees C dry-25 degrees C wet, 25 degrees C dry-37 degrees C dry and 25 degrees C dry-37 degrees C wet) were delivered to determine the role of temperature and humidity in the flow-induced apneic response of the larynx. The apneic index was calculated by prolonged expiratory time/baseline expiratory time.

RESULTS

Laryngeal dry room temperature air exposure induced an apneic response, and this response was reproducible and could be eliminated by humidification. In contrast, this apneic response could not be inhibited by increasing temperature alone. In addition, prolonged cold dry air stimulation did not evoke a tachyphylactic effect to normalize the breathing pattern.

CONCLUSION

Laryngeal cold dry air stimulation triggered an apneic response, which could be eliminated by humidification but not by the heating of air. These results suggest that using continuous positive airway pressure (CPAP) with humidified air decreases CPAP-induced apnea.

Novel therapeutic usage of low-dose doxepin hydrochloride

Low-dose doxepin hydrochloride (1, 3 and 6 mg) is a tricyclic antidepressant currently being investigated for the treatment of primary insomnia in adult and geriatric patients. Although it has been used at much higher doses to treat depression effectively for a number of decades, it offers a unique potency and selectivity for antagonizing the H1 (histamine) receptor at low doses. This mechanism of action may prove to be advantageous compared with other medications currently approved for the treatment of insomnia. This article reviews previous clinical studies using doxepin for insomnia and the recent clinical trial data, and briefly discusses other potential roles of this compound in clinical practice.

Two year reduction in sleep apnea symptoms and associated diabetes incidence after weight loss in severe obesity

STUDY OBJECTIVES

To evaluate the effect of bariatric surgery on sleep apnea symptoms and obesity-associated morbidity in patients with severe obesity.

DESIGN

Prospective study.

SETTING

University hospitals and community centers in Sweden.

INTERVENTION

We investigated the influence of weight loss surgery (n=1729) on sleep apnea symptoms and obesity-related morbidity using a conservatively treated group (n=1748) as a control.

MEASUREMENTS AND RESULTS

Baseline BMI in surgical group (42.2+/-4.4 kg/m(2)) and control group (40.1+/-4.6 kg/m(2)) changed -9.7+/-5 kg/m(2) and 0+/-3 kg/m(2), respectively, at 2-year follow-up. In the surgery group, there was a marked improvement in all obstructive sleep apnea (OSA) symptoms compared with the control group (P <0.001). Persistence of snoring (21.6 vs 65.5%, adjusted OR 0.14, 95% CI 0.10-0.19) and apnea (27.9 vs 71.3%, adjusted OR 0.16, 95% I 0.10-0.23) were much less in the surgery group compared with controls. Compared with subjects with no observed apnea at follow-up (n=2453), subjects who continued to have or developed observed apnea (n=404) had a higher incidence of diabetes (adjusted OR 2.03, 95% CI 1.19-3.47) and hypertriglyceridemia (adjusted OR 1.86, 95% CI 1.07-3.25) but not hypertension (adjusted OR 1.09, 95% CI 0.65-1.83) or hypercholesterolemia (adjusted OR 0.91, 95% CI 0.53-1.58).

CONCLUSION

Bariatric surgery results in a marked improvement in sleep apnea symptoms at 2 years. Despite adjustment for weight change and baseline central obesity, subjects reporting loss of OSA symptoms had a lower 2-year incidence of diabetes and hypertriglyceridemia. Improvement in OSA in patients losing weight may provide health benefits in addition to weight loss alone.

Cyclic phosphatidic acid stimulates respiration without producing vasopressor or tachycardiac effects in rats

The effects of a novel lipid mediator, cyclic phosphatidic acid (cPA), on respiratory and cardiovascular functions were examined in anesthetized rats. Intravenous (i.v.) administration of 3-O-carba-oleoyl-cPA at doses of 130 and 390 microg/kg produced dose-dependent increases in tidal volume and respiratory frequency, resulting in an increase in total ventilation. Heart rate was slightly decreased at a dose of 390 microg/kg, while systemic arterial pressure was not affected. Bilateral section of vagi and carotid sinus nerves designed to eliminate major regulatory inputs from the peripheral afferents to the respiratory center reduced these responses, but did not abolish them. These results indicate that cPA stimulates respiration, via central and peripheral mechanisms acting on the central respiratory rhythm generator in the brain stem. Administration of cPA may be of therapeutic value as a respiratory stimulant without producing vasopressor or tachycardiac effects, for treatment of respiratory disorders.

Atrial overdrive pacing compared to CPAP in patients with obstructive sleep apnoea syndrome

AIMS

Obstructive sleep apnoea (OSA) is associated with oxygen desaturation, blood pressure increase, and neurohumoral activation, resulting in possible detrimental effects on the cardiovascular system. Continuous positive airway pressure (CPAP) is the therapy of choice for OSA. In a recent study, nocturnal atrial overdrive pacing (pacing) reduced the severity of sleep apnoea in pacemaker patients. We compared the effects of CPAP with those of pacing in patients with OSA but without pacemaker indication or clinical signs of heart failure.

METHODS AND RESULTS

Ten patients with OSA on CPAP therapy were studied for three nights by polysomnography. During the nights that followed a night without any treatment (baseline), the patients were treated with CPAP or pacing in a random order. Pacing was performed with a temporary pacing lead. The pacing frequency was 15 b.p.m. higher than the baseline heart rate. The apnoea-hypopnoea index was 41.0 h(-1) (12.0-66.6) at baseline and was significantly lower during CPAP [2.2 h(-1) (0.3-12.4)] compared with pacing [39.1 h(-1) (8.2-78.5)]. Furthermore, duration and quality of sleep were significantly improved during CPAP when compared with pacing.

CONCLUSION

Nocturnal atrial overdrive pacing is no alternative therapeutic strategy to CPAP for the treatment of OSA in patients without clinical signs of heart failure and without conventional indication for anti-bradycardia pacing.

Alpha-7 and alpha-4 nicotinic receptor subunit immunoreactivity in genioglossus muscle motoneurons

In the present study, immunohistochemistry combined with retrograde labeling techniques were used to determine if hypoglossal motoneurons (HMNs), retrogradely labeled after cholera toxin B subunit (CTB) injection to the genioglossus muscle in rats, show immunoreactivity for alpha-7 and alpha-4 subunits of nicotinic acetylcholine receptors (nAChRs). CTB-positive HMNs projecting to the genioglossus muscle were consistently labeled throughout the rostrocaudal extent of the hypoglossal nuclei with the greatest labeling at and caudal to area postrema. Alpha-7 subunit immunoreactivity was found in 39.44+/-5.10% of 870 CTB-labeled motoneurons and the alpha-4 subunit in 51.01+/-3.71% of 983 CTB-positive neurons. Rostrally, the number of genioglossal motoneurons demonstrating immunoreactivity for the alpha-7 subunit was 45.85+/-10.04% compared to 34.96+/-5.11% at and caudal to area postrema (P>0.1). The number of genioglossal motoneurons that showed immunoreactivity for the alpha-4 subunit was 55.03+/-4.83% at and caudal to area postrema compared to 42.98+/-3.90% in rostral areas (P=0.074). These results demonstrate that nAChR immunoreactivity is present in genioglossal motoneurons and suggest a role for alpha-7 and alpha-4 subunits containing nAChRs in the regulation of upper airway patency.

Predictive value of Kushida index and acoustic pharyngometry for the evaluation of upper airway in subjects with or without obstructive sleep apnea

Acoustic pharyngometry is a relatively new noninvasive method that quantifies geometrically complexed pharyngeal dimensions. Our study aimed to investigate the predictability and usefulness of acoustic pharyngometry in diagnosis of obstructive sleep apnea (OSA), and we developed a prospective clinical trial in 16 subjects without apnea and 54 subjects with apnea. All seventy subjects received polysomnography (PSG) to assess the sleep architecture, including breathing and the degree of apnea hypopnea index. Acoustic pharyngometry was performed in four body positions (sitting, supine, right and left lateral) while awake with tidal breathing in addition to morphometric measurements (Kushida index) of oral cavity. This study shows that the cross-sectional area and volume of the upper airway is smaller in the supine position than any other positions. As well, the oropharyngeal junction area of the supine position is the most predictive parameter to discriminate between subjects with or without OSA. Acoustic pharyngometry can be a clinically useful tool for localizing the narrowed portion of the upper airway and predicting obstructive sleep apnea.

Contribution of cholinergic systems to state-dependent modulation of respiratory control

Respiration is altered during different stages of the sleep-wake cycle. We review the contribution of cholinergic systems to this alteration, with particular reference to the role of muscarinic acetylcholine receptors (MAchRs) during rapid eye movement (REM) sleep. Available evidence demonstrates that MAchRs have potent excitatory effects on medullary respiratory neurones and respiratory motoneurones, and are likely to contribute to changes in central chemosensitive drive to the respiratory control system. These effects are likely to be most prominent during REM sleep, when cholinergic brainstem neurones show peak activity levels. It is possible that MAchR dysfunction is involved in sleep-disordered breathing, such as obstructive sleep apnea.