The Impact of Intermittent Hypoxemia on Left Atrial Remodeling in Patients with Obstructive Sleep Apnea Syndrome

Correlation of the expression of circadian-clock genes with the severity of obstructive sleep apnea in patients

This study investigates the connection of Obstructive Sleep Apnea (OSA) with the expression and daily oscillation patterns of core circadian clock genes and related genes. OSA, a sleep disorder characterized by repetitive airway occlusion leading to nocturnal arousals, sleep fragmentation, and intermittent hypoxemia (IH), shares sleep dysfunction as an overlapping phenotype with circadian clock genes. The research involved 40 subjects (30 OSA patients and 10 normal controls), categorized into four groups based on Polysomnography (PSG) results: normal, mild, moderate, and severe. Peripheral blood samples were collected twice from each participant in the evening before and the morning after PSG examination. Using real-time quantitative reverse transcriptase-polymerase chain reaction (RT-qPCR), the study measured the expression levels of target genes in leukocytes. Results revealed changes in diurnal expression patterns of several genes (PER1, PER3, CRY1, BMAL1, CLOCK, HIF-1α, IL-1β, TNFα) in OSA groups compared to normal controls. While PER2, CRY2, and NPAS2 genes did not show diurnal patterns, their expression was significantly elevated in severe OSA. Notably, the expression levels of HIF-1α, IL-1β, and TNFα increased with OSA severity, consistent with the roles of IH and inflammation as clinical indicators in OSA. These findings not only demonstrate that circadian clock-related gene expression fluctuates with OSA but also provide potential molecular markers for early diagnosis and personalized treatment. By identifying biomarkers parallel to clinical indicators in OSA, this innovative study paves the way for future research and clinical applications in the field.

Association between obstructive sleep apnea and arrhythmia and heart rate variability among hypertensive patients

BACKGROUND

The relationship between obstructive sleep apnea (OSA) and the occurrence of arrhythmias and heart rate variability (HRV) in hypertensive patients is not elucidated. Our study investigates the association between OSA, arrhythmias, and HRV in hypertensive patients.

METHODS

We conducted a cross-sectional analysis involving hypertensive patients divided based on their apnea-hypopnea index (AHI) into two groups: the AHI ≤ 15 and the AHI > 15. All participants underwent polysomnography (PSG), 24-hour dynamic electrocardiography (DCG), cardiac Doppler ultrasound, and other relevant evaluations.

RESULTS

The AHI > 15 group showed a significantly higher prevalence of frequent atrial premature beats and atrial tachycardia (P = 0.030 and P = 0.035, respectively) than the AHI ≤ 15 group. Time-domain analysis indicated that the standard deviation of normal-to-normal R-R intervals (SDNN) and the standard deviation of every 5-minute normal-to-normal R-R intervals (SDANN) were significantly higher in the AHI > 15 group (P = 0.020 and P = 0.033, respectively). Frequency domain analysis revealed that the low-frequency (LF), high-frequency (HF) components, and the LF/HF ratio were also significantly elevated in the AHI > 15 group (P < 0.001, P = 0.031, and P = 0.028, respectively). Furthermore, left atrial diameter (LAD) was significantly larger in the AHI > 15 group (P < 0.001). Both univariate and multivariable linear regression analyses confirmed a significant association between PSG-derived independent variables and the dependent HRV parameters SDNN, LF, and LF/HF ratio (F = 8.929, P < 0.001; F = 14.832, P < 0.001; F = 5.917, P = 0.016, respectively).

CONCLUSIONS

Hypertensive patients with AHI > 15 are at an increased risk for atrial arrhythmias and left atrial dilation, with HRV significantly correlating with OSA severity.

Sex Differences in the Expression of Cardiac Remodeling and Inflammatory Cytokines in Patients with Obstructive Sleep Apnea and Atrial Fibrillation

Although there is a link between obstructive sleep apnea (OSA) and atrial fibrillation (AF) and numerous investigations have examined the mechanism of AF development in OSA patients, which includes cardiac remodeling, inflammation, and gap junction-related conduction disorder, there is limited information regarding the differences between the sexes. This study analyzes the impact of sex differences on the expression of cardiac remodeling, inflammatory cytokines, and gap junctions in patients with OSA and AF. A total of 154 individuals diagnosed with sleep-related breathing disorders (SRBDs) were enrolled in the study and underwent polysomnography and echocardiography. Significant OSA was defined as an apnea-hypopnea index (AHI) of ≥15 per hour. Exosomes were purified from the plasma of all SRBD patients and incubated in HL-1 cells to investigate their effects on inflammatory cytokines and GJA1 expression. The differences in cardiac remodeling and expression of these biomarkers in both sexes were analyzed. Of the 154 enrolled patients, 110 patients were male and 44 patients were female. The LA sizes and E/e' ratios of male OSA patients with concomitant AF were greater than those of control participants and those without AF (all p < 0.05). Meanwhile, female OSA patients with AF had a lower left ventricular ejection fraction than those OSA patients without AF and control subjects (p < 0.05). Regarding the expression of inflammatory cytokines and GJA1, the mRNA expression levels of GJA1 were lower and those of IL-1β were higher in those male OSA patients with AF than in those male OSA patients without AF and control subjects (p < 0.05). By contrast, mRNA expression levels of HIF-1α were higher in those female OSA patients with and without AF than in control subjects (p < 0.05). In conclusion, our study revealed sex-specific differences in the risk factors and biomarkers associated with AF development in patients with OSA.

Mechanisms of Atrial Fibrillation in Obstructive Sleep Apnoea

Obstructive sleep apnoea (OSA) is a strong independent risk factor for atrial fibrillation (AF). Emerging clinical data cite adverse effects of OSA on AF induction, maintenance, disease severity, and responsiveness to treatment. Prevention using continuous positive airway pressure (CPAP) is effective in some groups but is limited by its poor compliance. Thus, an improved understanding of the underlying arrhythmogenic mechanisms will facilitate the development of novel therapies and/or better selection of those currently available to complement CPAP in alleviating the burden of AF in OSA. Arrhythmogenesis in OSA is a multifactorial process characterised by a combination of acute atrial stimulation on a background of chronic electrical, structural, and autonomic remodelling. Chronic intermittent hypoxia (CIH), a key feature of OSA, is associated with long-term adaptive changes in myocyte ion channel currents, sensitising the atria to episodic bursts of autonomic reflex activity. CIH is also a potent driver of inflammatory and hypoxic stress, leading to fibrosis, connexin downregulation, and conduction slowing. Atrial stretch is brought about by negative thoracic pressure (NTP) swings during apnoea, promoting further chronic structural remodelling, as well as acutely dysregulating calcium handling and electrical function. Here, we provide an up-to-date review of these topical mechanistic insights and their roles in arrhythmia.

Recent trends in the nanozeolites-based oxygen concentrators and their application in respiratory disorders

Medical-grade oxygen is the basic need for all medical complications, especially in respiratory-based discomforts. There was a drastic increase in the demand for medical-grade oxygen during the current pandemic. The non-availability of medical-grade oxygen led to several complications, including death. The oxygen concentrator was only the last hope for the patient during COVID-19 pandemic around the globe. The demands also are everlasting during other microbial respiratory infections. The yield of oxygen using conventional molecular zeolites in the traditional oxygen concentrator process is less than the yield noticed when its nano-form is used. Nanotechnology has enlightened hope for the efficient production of oxygen by such oxygen concentrators. Here in the current review work, the authors have highlighted the basic structural features of oxygen concentrators along with the current working principle. Besides, it has been tried to bridge the gap between conventional oxygen concentrators and advanced ones by using nanotechnology. Nanoparticles being usually within 100 nm in size have a high surface area to volume ratio, which makes them suitable adsorbents for oxygen. Here authors have suggested the use of nano zeolite in place of molecular zeolites in the oxygen concentrator for efficient delivery of oxygen by the oxygen concentrators.

Periostin and TNF-α expression levels in peripheral blood of patients with acute cerebral infarction combined with obstructive sleep apnea syndrome and their predictive value for clinical prognosis

OBJECTIVE

To detect the expression levels of periostin and tumour necrosis factor-α (TNF-α) in patients with acute cerebral infarction (ACI) combined with obstructive sleep apnea syndrome (OSAS) and to investigate their predictive value for clinical prognosis.

METHODS

In this case‒control study, serum periostin and TNF-α levels were measured using ELISA, and patients were scored on the National Institutes of Health Stroke Scale (NIHSS) and modified Rankin Scale (mRS). Receiver operating characteristic curve(ROC) were generated to analyse the effect of peripheral blood periostin and TNF-α levels on poor prognosis.

RESULTS

NIHSS score, mRS score and peripheral blood periostin and TNF-α levels were higher in the observation group than in the control group (P < 0.001); serum periostin and TNF-α levels were positively correlated with the NIHSS score and mRS score (P < 0.001). Serum periostin and TNF-α levels were higher in patients with a poor prognosis than in those with a favourable prognosis (P < 0.001); the area under curve (AUC) values for the diagnosis of poor prognosis based on TNF-α, periostin or both factors were 0.868 (95% CI: 0.781-0.954), 0.834 (95% CI: 0.734-0.934), and 0.875 (95% CI: 0.792 ~ 0.958), with sensitivities of 0.654, 0.846, and 0.654 and specificities of 0.944, 0.750, and 0.917, respectively.

CONCLUSION

Patients with ACI combined with OSAS have elevated peripheral blood periostin and TNF-α levels, and the combination of these two factors has high predictive value for poor prognosis.