Decrease of perforin positive CD3+γδ-T cells in patients with obstructive sleep disordered breathing

Potential Pathophysiological Pathways in the Complex Relationships between OSA and Cancer

Several epidemiological and clinical studies have suggested a relationship between obstructive sleep apnea (OSA) and a higher incidence or severity of cancer. This relationship appears to be dependent on a myriad of factors. These include non-modifiable factors, such as age and gender; and modifiable or preventable factors, such as specific comorbidities (especially obesity), the use of particular treatments, and, above all, the histological type or location of the cancer. Heterogeneity in the relationship between OSA and cancer is also related to the influences of intermittent hypoxemia (a hallmark feature of OSA), among others, on metabolism and the microenvironment of different types of tumoral cells. The hypoxia inducible transcription factor (HIF-1α), a molecule activated and expressed in situations of hypoxemia, seems to be key to enabling a variety of pathophysiological mechanisms that are becoming increasingly better recognized. These mechanisms appear to be operationally involved via alterations in different cellular functions (mainly involving the immune system) and molecular functions, and by inducing modifications in the microbiome. This, in turn, may individually or collectively increase the risk of cancer, which is then, further modulated by the genetic susceptibility of the individual. Here, we provide an updated and brief review of the different pathophysiological pathways that have been identified and could explain the relationship between OSA and cancer. We also identify future challenges that need to be overcome in this intriguing field of research.

Cellular Immune Dysfunction in Obstructive Sleep Apnea

Obstructive sleep apnea (OSA) is the most common sleep-related breathing disorder. Repetitive pauses in breathing during sleep cause a brief but recurrent decrease in oxygen saturation in organs and tissues (chronic intermittent tissue hypoxia). Many studies have proven a pro-inflammatory status in OSA patients. However, few reports are available on the effects of OSA on the cellular immune system, mostly focusing on single immune cell types and their subtypes. The aim of this Mini-Review is to summarize these reports, as OSA is associated with a high prevalence and comorbidities such as atherosclerosis, which are known to involve the cellular immune system.

The effect of apnea management on novel coronavirus infection: A study on patients with obstructive sleep apnea

OBJECTIVE

To assess the frequency of coronavirus disease-2019 (COVID-19) and the effect of obstructive sleep apnea (OSA) management on COVID-19 among patients with confirmed OSA.

DESIGN

Cross-sectional telephone interview survey.

SETTING

Academic sleep labs.

PARTICIPANTS

Iranian adults ≥ 18 years old with confirmed OSA.

RESULTS

Among 275 participants with OSA, 20% (n = 55) were suspected to have history of COVID-19 but had no positive test, and 18% (n = 51) were in the definite COVID-19 group according to their reported symptoms or confirmed positive test. Having severe OSA (apnea hypopnea index ≥ 30) was associated with an increased risk of definite COVID-19, with an odds ratio (OR) with 95% confidence interval (95% CI) of 2.31 (0.87-5.55) compared to having mild OSA in definite COVID-19 group. Those not undergoing treatment for OSA had an OR (95% CI) of 2.43 (1.26-4.67) for definite COVID-19 compared to those accepting treatment in definite COVID-19 group. Total sleep times (TSTs) were 354, 340, and 320 minutes in healthy, suspected, and COVID-19 groups, respectively; TST was associated with COVID-19 (P-value = .04). Similarly, sleep efficiency (SE) scores were 75.7, 74.2, and 67.9% for the healthy, suspected, and COVID-19 groups, respectively (P-value = .005); Beck Depression scores were 13.8, 13.0, and 17.7, respectively (P-value = .056).

CONCLUSIONS

OSA as a proinflammatory condition with multiple comorbidities may be a contributing factor to developing COVID-19. Greater OSA severity, no treatment for OSA, and lower TST and SE were associated with increased COVID-19 prevalence among patients with OSA.

Severe depletion of peripheral blood dendritic cell subsets in obstructive sleep apnea patients: A new link with cancer?

Recent evidence suggests that alterations of the immune responses are associated with the inflammatory nature of obstructive sleep apnea (OSA) and of its related co-morbidities. In this scenario, we asked whether circulating dendritic cell (DC) subsets may be possible players as their role has not yet been detailed. The frequency distribution of peripheral blood myeloid (mDC1 and mDC2) and plasmacytoid (p) DCs was investigated by mean of multi-parametric flow cytometry in 45 OSA patients (mean age: 53 yrs; M = 29) at the time of the first diagnosis and compared to 30 age- and sex-matched healthy controls. Oxidative burst (OB) and serum levels of tumor necrosis factor (TNF)-α, (interleukin) (IL)-6, interferon (INF)-γ, IL-2, IL-4, IL-10 and vascular endothelial growth factor (VEGF) were also analyzed. All subsets of circulating DCs were significantly depleted in OSA patients as compared to healthy subjects (p < 0.01, in all instances), with mDC2 and pDC subtypes being more severely compromised. These findings were co-existing with higher levels of OB along with an increased expression of IL-6, IL-10, TNF-α, IFN-γ, and VEGF (p < 0.005 in all instances). In particular, IL6 levels were significantly higher (p = 0.013) in severe OSA patients (apnea/hypopnea index >30) and were inversely correlated with both mDC2 (r = -0.802, p < 0.007) and pDC (r = -0.317, p = 0.04) subsets. We first provide evidence for a constitutive reduction of all circulating DC subsets in OSA patients. Perturbation of DCs coexists with an inflammatory milieu and is negatively correlated with the expression of IL-6, which is actually recognized as a pivotal inhibitor of DC maturation. Future studies exploring the contribution of DCs in the pathogenesis of OSA and of its complications should be encouraged.