Prevalence and Factors Associated with Rapid Eye Movement-Related Obstructive Sleep Apnea in Patients with Narcolepsy

Hamza O Dhafar,1 Ali A Awadh,2 Salih A Aleissi,1 Galal Eldin Abbas Eltayeb,3 Samar Z Nashwan,1 Ahmed S BaHammam1,4 1The University Sleep Disorders Center, Department of Medicine, College of Medicine, King Saud University, Riyadh, Saudi Arabia; 2Seha Virtual Hospital, Ministry of Health, Riyadh, Saudi Arabia; 3Department of Management Information Systems, College of Business and Economics, Qassim University, Buraydah, Saudi Arabia; 4The Strategic Technologies Program of the National Plan for Sciences and Technology and Innovation in the Kingdom of Saudi Arabia, Riyadh, Saudi ArabiaCorrespondence: Ahmed S BaHammam, University Sleep Disorders Center, Department of Medicine, College of Medicine, King Saud University, Box 225503, Riyadh, 11324, Saudi Arabia, Email [email protected]: Data on the prevalence and correlates of rapid eye movement (REM)–related obstructive sleep apnea (REM-OSA) in narcolepsy remains limited. This study aimed to assess the prevalence and independent associated factors with OSA and REM-OSA in patients with narcolepsy, and to compare the distribution of REM-OSA between patients with narcolepsy and matched controls without narcolepsy.Patients and Methods: This retrospective study of a prospectively collected cohort included 190 adult patients with narcolepsy (narcolepsy type 1 [NT1] = 119, narcolepsy type 2 [NT2] = 71) who underwent polysomnography and multiple sleep latency test at the University Sleep Disorders Center, King Saud University Medical City, between January 2007 and February 2022. REM-OSA was defined as an apnea–hypopnea index (AHI) ≥ 5, AHI-REM/AHI–non–rapid eye movement (NREM) ≥ 2, AHI-NREM < 8, and REM sleep duration > 10.5 minutes. A total of 106 patients with narcolepsy were diagnosed with OSA. A control group of 122 patients with OSA but without narcolepsy, matched by age, sex, AHI, and BMI, was used for comparison. Logistic regression identified independent associated factors with OSA and REM-OSA.Results: OSA was diagnosed in 106 patients with narcolepsy (55.8%). REM-OSA was present in 26.4% of these cases, with a slightly higher prevalence in NT2 (30%) than in NT1 (24%). REM-OSA showed a trend toward higher prevalence in the narcolepsy group compared to controls (26.4% vs 17.2%, OR: 1.73, 95% CI: 0.91– 3.27, p = 0.09). Male sex, BMI, and arousal index were independent correlates of OSA among patients with narcolepsy. REM-OSA was independently associated with arousal index and REM sleep duration.Conclusion: OSA and REM-OSA are common in patients with narcolepsy. REM-OSA was more prevalent in the narcolepsy group than in matched controls, suggesting a potential association between narcolepsy and REM-OSA that warrants investigation in larger cohorts.Plain Language Summary: People with narcolepsy often struggle with excessive daytime sleepiness and disrupted nighttime sleep. When another sleep disorder, such as obstructive sleep apnea (OSA), occurs alongside narcolepsy, it can make symptoms worse. A specific form of OSA, known as REM-OSA (which primarily occurs during rapid eye movement sleep), has been associated with an increased risk of heart and metabolic conditions. However, studies examining REM-OSA in people with narcolepsy remain limited.In this study, we evaluated 190 adults with narcolepsy and found that more than half had OSA. Among those with OSA, over one in four also had REM-OSA. We compared these patients to a group of individuals who had OSA but not narcolepsy. The two groups were matched by age, sex, apnea severity, and body mass index (BMI). We found that REM-OSA was more common in people with narcolepsy than in the matched controls. Although the difference was not statistically significant, the trend suggests a possible link worth further investigation.Understanding the relationship between narcolepsy and REM-OSA is important for improving diagnosis and treatment. A better understanding of this overlap may help improve patient outcomes. More research in larger groups is needed to confirm this connection.Keywords: sleep-disordered breathing, REM sleep, arousal index, sleep fragmentation, polysomnography, multiple sleep latency tes

Biotechnological Perspective of Reactive Oxygen Species (ROS)-Mediated Stress Tolerance in Plants

All environmental cues lead to develop secondary stress conditions like osmotic and oxidative stress conditions that reduces average crop yields by more than 50% every year. The univalent reduction of molecular oxygen (O2) in metabolic reactions consequently produces superoxide anions (O2•−) and other reactive oxygen species (ROS) ubiquitously in all compartments of the cell that disturbs redox potential and causes threat to cellular organelles. The production of ROS further increases under stress conditions and especially in combination with high light intensity. Plants have evolved different strategies to minimize the accumulation of excess ROS like avoidance mechanisms such as physiological adaptation, efficient photosystems such as C4 or CAM metabolism and scavenging mechanisms through production of antioxidants and antioxidative enzymes. Ascorbate-glutathione pathway plays an important role in detoxifying excess ROS in plant cells, which includes superoxide dismutase (SOD) and ascorbate peroxidase (APX) in detoxifying O2•−radical and hydrogen peroxide (H2O2) respectively, monodehydroascorbate reductase (MDHAR), dehydroascorbate reductase (DHAR) and glutathione reductase (GR) involved in recycling of reduced substrates such as ascorbate and glutathione. Efficient ROS management is one of the strategies used by tolerant plants to survive and perform cellular activities under stress conditions. The present chapter describes different sites of ROS generation and and their consequences under abiotic stress conditions and also described the approaches to overcome oxidative stress through genomics and genetic engineering

What about the detoxification mechanisms underlying ozone sensitivity in Liriodendron tulipifera?

Liriodendron tulipifera (known as the tulip tree) is a woody species that has been previously classified as sensitive to ozone (O3) in terms of visible leaf injuries and photosynthetic primary reactions. The objective of this work is to give a thorough description of the detoxification mechanisms that are at the basis of O3sensitivity. Biochemical and molecular markers were used to characterize the response of 1-year-old saplings exposed to O3(120 ppb, 5 h dayâ\u88\u921, for 45 consecutive days) under controlled conditions. O3effects resulted in a less efficient metabolism of Halliwell-Asada cycle as confirmed by the diminished capacity to convert the oxidized forms of ascorbate and glutathione in the reduced ones (AsA and GSH, respectively). The reduced activity of AsA and GSH regenerating enzymes indicates that de novo AsA biosynthesis occurred. This compound could be a cofactor of several plant-specific enzymes that are involved in the early part of the phenylpropanoid and flavonoid biosynthesis pathway, as confirmed by the significant rise of PAL activity (+75%). The induction of the defence-related secondary metabolites (in particular, rutin and caffeic acid were about threefold higher) and the concomitant increase in transcript levels of PAL and CHS genes (+120 and 30%, respectively) suggest that L. tulipifera utilized this route in order to partially counteract the O3-induced oxidative damage