Obstructive sleep apnea, low transferrin saturation levels, and male-pattern baldness

Obstructive sleep apnea affects cognition: dual effects of intermittent hypoxia on neurons

Obstructive sleep apnea (OSA) is a common respiratory disorder. Multiple organs, especially the central nervous system (CNS), are damaged, and dysfunctional when intermittent hypoxia (IH) occurs during sleep for a long time. The quality of life of individuals with OSA is significantly impacted by cognitive decline, which also escalates the financial strain on their families. Consequently, the development of novel therapies becomes imperative. IH induces oxidative stress, endoplasmic reticulum stress, iron deposition, and neuroinflammation in neurons. Synaptic dysfunction, reactive gliosis, apoptosis, neuroinflammation, and inhibition of neurogenesis can lead to learning and long-term memory impairment. In addition to nerve injury, the role of IH in neuroprotection was also explored. While causing neuron damage, IH activates the neuronal self-repairing mechanism by regulating antioxidant capacity and preventing toxic protein deposition. By stimulating the proliferation and differentiation of neural stem cells (NSCs), IH has the potential to enhance the ratio of neonatal neurons and counteract the decline in neuron numbers. This review emphasizes the perspectives and opportunities for the neuroprotective effects of IH and informs novel insights and therapeutic strategies in OSA.

Sleep quality in men with androgenetic alopecia

PURPOSE

Sleep disturbances affect human health and contribute to several comorbidities. In men, androgenetic alopecia (AGA) is a common, non-scarring form of hair loss that affects a patient's self-esteem. There are limited data regarding the association between poor sleep quality and male AGA. We aimed to compare the prevalence of sleep abnormalities between male patients with AGA and controls to identify an association between the two conditions.

METHODS

A case-control study on patients with AGA and age-matched controls was conducted. Participants completed a standardized questionnaire that contained self-evaluated sleep measures, including Pittsburgh Sleep Quality Index (PSQI), Epworth Sleepiness Scale, and STOP-BANG questionnaire. Patients with AGA were classified into mild, moderate, and severe subgroups according to the Hamilton-Norwood classification for stratified analyses. Data between groups and among subgroups were compared.

RESULTS

Of 446 male participants, 223 (50%) were in the AGA group, and the remainder (50%) were in the control group. Multivariable logistic regression analysis revealed that hypertension (odds ratio [OR] = 1.90, 95% confidence interval [CI] = 1.16-3.11, p = 0.011) and STOP-BANG score ≥ 5 (OR = 2.05, 95%CI = 1.15-3.66, p = 0.015) were associated with AGA. For subgroup analyses, ordinal logistic regression model showed a significant association between severe AGA and three sleep profiles, namely total sleep time ≤ 6 h (OR = 2.16, 95%CI = 1.02-4.57, p = 0.044), PSQI > 5 (OR = 3.72, 95%CI = 1.42-9.72, p = 0.008), and STOP-BANG score ≥ 5 (OR = 3.01, 95%CI = 1.11-8.13, p = 0.030).

CONCLUSION

Our findings revealed an association between sleep disturbances and AGA, which may help guide appropriate management in these patients.

Serum Transferrin Level Is Associated with the Severity of Obstructive Sleep Apnea Independently of Obesity: A Propensity Score-Match Observational Study

INTRODUCTION

Dysregulation of iron metabolism is closely associated with the development of obesity and obstructive sleep apnea (OSA), but little is known about the relationship between serum transferrin (TF) level and OSA severity. We aimed to verify this relationship and fit into account for obesity-related confounders among bariatric candidates.

METHODS

We compared data retrospectively collected in 270 bariatric candidates. A propensity score-matched (PSM) analysis was used to determine the impact of iron metabolism on OSA severity independently of obesity. Univariate analysis was used to evaluate the relationship between serum TF level and the severity of OSA reflected by hypoxia and night awakenings parameters. Serum TF level to predict the severity of OSA was assessed by using univariate and multiple logistic regression model.

RESULTS

The preliminary analysis showed that serum ferritin (113 ng/mL [50-203] vs. 79 ng/mL [40-130], p = 0.009) and TF (2.72 g/L [2.46-3.09] vs. 2.65 g/L [2.34-2.93], p = 0.039) level was significantly higher in the moderate/severe OSA group than the no/mild OSA group. After PSM analysis, there were 75 patients in each group and only serum TF level remained significant (p = 0.014). The proportion of patients with combined T2D and hyperlipidemia also remained higher in moderate/severe OSA groups. Univariate analysis showed that the group with higher degree of hypoxia had higher serum TF levels no matter the severity of OSA was grouped by oxygen desaturation index (ODI; 2.79 g/L [2.56-3.06] vs. 2.55 g/L [2.22-2.84], p < 0.001) or minimum oxygen saturation (SpO2nadir; 2.75 g/L [2.50-3.03] vs. 2.56 g/L [2.24-2.92], p = 0.009). Univariate and multiple logistic regression analysis further showed that serum TF level emerged as a significant and independent factor associated with OSA severity especially grouped by ODI (odds ratio: 2.91, 95% CI: 1.36-6.23, p = 0.006).

CONCLUSION

The existence of OSA exacerbates obesity comorbidities, particularly type 2 diabetes and hyperlipidemia. Serum TF level is associated with the severity of OSA independently of obesity and might be a potential identification and therapeutic targets.

Involvement of Hepcidin in Cognitive Damage Induced by Chronic Intermittent Hypoxia in Mice

Obstructive sleep apnea (OSA) patients exhibit different degrees of cognitive impairment, which is related to the activation of reactive oxygen species (ROS) production by chronic intermittent hypoxia (CIH) and the deposition of iron in the brain. As a central regulator of iron homeostasis, whether hepcidin is involved in OSA-induced cognitive impairment has not been clarified. In order to simulate OSA, we established the mouse model by reducing the percentage of inspired O₂ (FiO₂) from 21% to 5%, 20 times/h for 8 h/day. We found hepcidin was rising during CIH, along with increasing iron levels and neuron loss. Then, we constructed a mouse with astrocyte-specific knockdown hepcidin gene (shHamp). During CIH exposure, the shHamp mice showed a lower level of total iron and neuronal iron in the hippocampus, via stabilizing ferroportin 1 (FPN1) and decreasing L-ferritin (FTL) levels, when compared with wild-type (WT) mice. Furthermore, the shHamp mice showed a decrease of ROS by downregulating the elevated NADPH oxidase (NOX2) and 4-hydroxynonenal (4-HNE) levels mediated by CIH. In addition, the shHamp mice presented improved cognitive deficit by improving synaptic plasticity and BDNF expression in the hippocampus when subjected to CIH. Therefore, our data revealed that highly expressed hepcidin might promote the degradation of FPN1, resulting in neuronal iron deposition, oxidative stress damage, reduced synaptic plasticity, and impaired cognitive performance during CIH exposure.

Sleep Apnea and Skin

Purpose of the Review

Skin disease is associated with obstructive sleep apnea (OSA) both epidemiologically and mechanistically. In this review we highlight conditions which have a well-established link to obstructive sleep apnea, such as psoriasis and atopic dermatitis.

Recent findings

We describe putative mechanistic links between OSA and skin disease involving inflammatory pathways, obesity, mechanical upper airways obstruction, and hypoxia. In the context of these mechanisms we describe specific skin conditions, and other conditions which are associated with both skin manifestations (including hair/nail findings) and OSA. The risks/ benefits of CPAP in the context of skin disease are also reviewed.

Summary

We conclude that further research is needed to understand the mechanisms behind the associations between OSA and skin disease. Given the frequent co-occurrence of OSA and skin conditions, there would be great benefit for OSA clinical trials to consider improvement in skin disease as an outcome measure.