Sleep apnea syndrome in endocrine clinics

Unraveling the Complexities of Oxidative Stress and Inflammation Biomarkers in Obstructive Sleep Apnea Syndrome: A Comprehensive Review

BACKGROUND

Obstructive sleep apnea syndrome (OSAS), affecting approximately 1 billion adults globally, is characterized by recurrent airway obstruction during sleep, leading to oxygen desaturation, elevated carbon dioxide levels, and disrupted sleep architecture. OSAS significantly impacts quality of life and is associated with increased morbidity and mortality, particularly in the cardiovascular and cognitive domains. The cyclic pattern of intermittent hypoxia in OSAS triggers oxidative stress, contributing to cellular damage. This review explores the intricate relationship between OSAS and oxidative stress, shedding light on molecular mechanisms and potential therapeutic interventions.

METHODS

A comprehensive review spanning from 2000 to 2023 was conducted using the PubMed, Cochrane, and EMBASE databases. Inclusion criteria encompassed English articles focusing on adults or animals and reporting values for oxidative stress and inflammation biomarkers.

RESULTS

The review delineates the imbalance between pro-inflammatory and anti-inflammatory factors in OSAS, leading to heightened oxidative stress. Reactive oxygen species biomarkers, nitric oxide, inflammatory cytokines, endothelial dysfunction, and antioxidant defense mechanisms are explored in the context of OSAS. OSAS-related complications include cardiovascular disorders, neurological impairments, metabolic dysfunction, and a potential link to cancer. This review emphasizes the potential of antioxidant therapy as a complementary treatment strategy.

CONCLUSIONS

Understanding the molecular intricacies of oxidative stress in OSAS is crucial for developing targeted therapeutic interventions. The comprehensive analysis of biomarkers provides insights into the complex interplay between OSAS and systemic complications, offering avenues for future research and therapeutic advancements in this multifaceted sleep disorder.

Pathophysiological mechanisms and therapeutic approaches in obstructive sleep apnea syndrome

Obstructive sleep apnea syndrome (OSAS) is a common breathing disorder in sleep in which the airways narrow or collapse during sleep, causing obstructive sleep apnea. The prevalence of OSAS continues to rise worldwide, particularly in middle-aged and elderly individuals. The mechanism of upper airway collapse is incompletely understood but is associated with several factors, including obesity, craniofacial changes, altered muscle function in the upper airway, pharyngeal neuropathy, and fluid shifts to the neck. The main characteristics of OSAS are recurrent pauses in respiration, which lead to intermittent hypoxia (IH) and hypercapnia, accompanied by blood oxygen desaturation and arousal during sleep, which sharply increases the risk of several diseases. This paper first briefly describes the epidemiology, incidence, and pathophysiological mechanisms of OSAS. Next, the alterations in relevant signaling pathways induced by IH are systematically reviewed and discussed. For example, IH can induce gut microbiota (GM) dysbiosis, impair the intestinal barrier, and alter intestinal metabolites. These mechanisms ultimately lead to secondary oxidative stress, systemic inflammation, and sympathetic activation. We then summarize the effects of IH on disease pathogenesis, including cardiocerebrovascular disorders, neurological disorders, metabolic diseases, cancer, reproductive disorders, and COVID-19. Finally, different therapeutic strategies for OSAS caused by different causes are proposed. Multidisciplinary approaches and shared decision-making are necessary for the successful treatment of OSAS in the future, but more randomized controlled trials are needed for further evaluation to define what treatments are best for specific OSAS patients.

Global psychological assessment with the evaluation of life and sleep quality and sexual and cognitive function in a large number of patients with acromegaly: a cross-sectional study

OBJECTIVE

Acromegaly is associated with somatic disfigurements which impair self-perception of well-being and quality of life. Nowadays, limited data are available on the interplay between hormonal excess and psychological discomfort. The study aimed at investigating the psychological profile, sleep quality, sexual function, cognitive functions, and quality of life in patients with acromegaly.

METHODS

In 223 acromegaly patients from 5 referral centres, global psychological profile, sleep quality, sexual function, cognitive function, and quality of life were investigated.

RESULTS

Depression was found in ~30% of patients, and anxiety in two-thirds, together with severe discomfort in body image mainly in women. Obstructive sleep apnoea syndrome risk and sleep disorders were found in >50% of patients and daily sleepiness in ~20%. Sexual dysfunction was reported in most of the patients, with the most severe impairment in women. Cognitive functions were compromised in ~10% of cases. Disease duration and patient's age and gender were the main determinants of these psychopathological conditions. Depression (P = 0.047), somatic-affective mood lowering (P = 0.021), state (P < 0.001) and trait (P = 0.013) anxiety, and body image distortion in body uneasiness test A (P < 0.001) and B (P = 0.006) were significantly worsened in patients <45 years and slightly worsened in those with disease duration less than 2 years. Male (P < 0.001) and female (P < 0.001) sexual function scores were significantly worsened in patients aged >64 years and slightly worsened in those with disease duration for more than 10 years, particularly in presence of cardiometabolic and respiratory complications. Cognitive symptoms were slightly worsened in older patients and in those with long disease duration.

CONCLUSIONS

Acromegaly is associated with a relevant impairment of psychological profile persisting despite remission and long-term medical treatment.

Diagnosis and management of hypertension in patients with Cushing's syndrome: a position statement and consensus of the Working Group on Endocrine Hypertension of the European Society of Hypertension

Endogenous/exogenous Cushing's syndrome is characterized by a cluster of systemic manifestations of hypercortisolism, which cause increased cardiovascular risk. Its biological basis is glucocorticoid excess, acting on various pathogenic processes inducing cardiovascular damage. Hypertension is a common feature in Cushing's syndrome and may persist after normalizing hormone excess and discontinuing steroid therapy. In endogenous Cushing's syndrome, the earlier the diagnosis the sooner management can be employed to offset the deleterious effects of excess cortisol. Such management includes combined treatments directed against the underlying cause and tailored antihypertensive drugs aimed at controlling the consequences of glucocorticoid excess. Experts on endocrine hypertension and members of the Working Group on Endocrine Hypertension of the European Society of Hypertension (ESH) prepared this Consensus document, which summarizes the current knowledge in epidemiology, genetics, diagnosis, and treatment of hypertension in Cushing's syndrome.

Changes in cortisol levels by continuous positive airway pressure in patients with obstructive sleep apnoea: Meta-analysis of 637 individuals

BACKGROUND

Obesity, obstructive sleep apnoea (OSA) and hypertension frequently coexist and are associated with elevated cortisol levels. Identification and treatment of such patients is important when investigating for suspected Cushing's syndrome and hypertension. Studies of the impact of continuous positive airway pressure (CPAP) on cortisol and blood pressure are limited by the small sample size and show conflicting findings. We conducted a meta-analysis to document changes in the levels of cortisol and blood pressure in response to CPAP treatment of OSA.

METHODS

Meta-analysis was conducted using RevMan (v5.3) and expressed in standardized mean difference (SMD) for catecholamines and mean difference for systolic (SBP) and diastolic blood pressure (DBP). The quality of the studies was evaluated using standard tools for assessing the risk of bias.

RESULTS

A total of 22 studies met our search criteria; they consisted of 16 prospective cohort studies (PCS) that recruited 385 participants and six randomized control trials (RCT) totalling 252 participants. The range of mean age was 41-62 years and BMI 27.2-35.1 kg/m² . CPAP treatment reduced plasma cortisol levels in PCS: SMD = -0.28 [95% confidence interval (95% CI) = -0.45 to -0.12], I²  = 0%, p = .79 and in RCT: SMD = -0.39 (95% CI = -0.75 to -0.03), I²  = 28.3%, p = .25. CPAP treatment reduced SBP by 5.4 mmHg (95% CI = 1.7-9.1) and DBP by 3.3 mmHg (95% CI = 1.0-5.7). Interstudy heterogeneity was low for all studies. Bias in most RCT arose from the lack of blinding of participants and personnel.

CONCLUSION

CPAP treatment in individuals with OSA reduces cortisol levels and blood pressure.

Nonalcoholic fatty liver disease is associated with the development of obstructive sleep apnea

Increasing evidence suggests that obstructive sleep apnea (OSA) is a metabolic syndrome-related disease; however, the association between nonalcoholic fatty liver disease (NAFLD) and OSA is not firmly established. In this study, we investigated the relationship between NAFLD and OSA in a general population drawn from a nationwide population-based cohort. Data from the Korean National Health Insurance System between January 2009 and December 2009 were analyzed using Cox proportional hazards model. NAFLD was defined as a fatty liver index (FLI) ≥ 60 in patients without excessive alcohol consumption (who were excluded from the study). Newly diagnosed OSA during follow-up was identified using claims data. Among the 8,116,524 participants, 22.6% had an FLI score of 30–60 and 11.5% had an FLI ≥ 60. During median follow-up of 6.3 years, 45,143 cases of incident OSA occurred. In multivariable analysis, the risk of OSA was significantly higher in the higher FLI groups (adjusted hazard ratio [aHR] 1.15, 95% confidence interval [CI] 1.12–1.18 for FLI 30–60 and aHR 1.21, 95% CI 1.17–1.26 for FLI ≥ 60). These findings were consistent regardless of body mass index and presence of abdominal obesity. In conclusion, a high FLI score may help identify individuals with a high risk of OSA. Understanding the association between NAFLD and OSA may have clinical implications for risk-stratification of individuals with NAFLD.

Hypothalamic-Pituitary Diseases and Erectile Dysfunction

Several hormones contribute to ensure penile erection, a neurovascular phenomenon in which nitric oxide plays a major role. Erectile dysfunction (ED), which is defined as the persistent inability to obtain or maintain penile erection sufficient for a satisfactory sexual performance, may be due to arteriogenic, neurogenic, iatrogenic, but also endocrinological causes. The hypothalamus–pituitary axis plays a central role in the endocrine system and represents a fundamental link between the brain and peripheral glands, including gonads. Therefore, the hormonal production of the hypothalamic–pituitary axis can control various aspects of sexual function and its dysregulation can compromise erectile function. In addition, excess and deficiency of pituitary hormones or metabolic alterations that are associated with some pituitary diseases (e.g., Cushing’s disease and acromegaly, hypopituitarism) can determine the development of ED with different mechanisms. Thus, the present review aimed to explore the relationship between hypothalamic and pituitary diseases based on the most recent clinical and experimental evidence.

Free Radical Oxidation of Lipids as an Indicator of the Effectiveness of CPAP Therapy in Apnea Syndrome

The processes of free radical lipid oxidation were studied in 47 patients with moderate to severe obstructive sleep apnea syndrome before and after 1-month course of CPAP-therapy (continuous positive airway pressure). The control group consisted of 13 people without clinically confirmed apnea. The material for the study was serum, blood plasma, and erythrocyte hemolysate. The levels of LPO products and antioxidant defense were determined spectrophotometrically and spectrofluorometrically. The changes revealed in patients with obstructive sleep apnea syndrome after CPAP therapy indicate a decrease in the intensity of LPO and restoration of the balance in the "LPO-antioxidant defense" system.

Clinical presentation and management of acromegaly in elderly patients

BACKGROUND AND AIM

Acromegaly is a rare disease with a peak of incidence in early adulthood. However, enhanced awareness of this disease, combined with wide availability of magnetic resonance imaging (MRI), has increased the diagnosis of forms with mild presentation, especially in elderly patients. Moreover, due to increased life expectancy and proactive individualized treatment, patients with early-onset acromegaly are today aging. The aim of our study was to describe our cohort of elderly patients with acromegaly.

MATERIALS AND METHODS

This is a cross-sectional retrospective study of 96 outpatients. Clinical, endocrine, treatment, and follow-up data were collected using the electronic database of the University Hospital of Padova, Italy.

RESULTS

We diagnosed acromegaly in 13 patients, aged ≥65 years, presenting with relatively small adenomas and low IGF-1 secretion. Among them, 11 patients were initially treated with medical therapy and half normalized hormonal levels after 6 months without undergoing neurosurgery (TNS). Remission was achieved after TNS in three out of four patients (primary TNS in two); ten patients presented controlled acromegaly at the last visit. Acromegaly-related comorbidities (colon polyps, thyroid cancer, adrenal incidentaloma, hypertension, and bone disease) were more prevalent in patients who had an early diagnosis (31 patients, characterized by a longer follow-up of 24 years) than in those diagnosed aged ≥65 years (5 years of follow-up).

CONCLUSIONS

Elderly acromegalic patients are not uncommon. Primary medical therapy is a reasonable option and is effectively used, while the rate of surgical success is not reduced. A careful cost-benefit balance is suggested. Disease-specific comorbidities are more prevalent in acromegalic patients with a longer follow-up rather than in those diagnosed aged ≥65 years.

The Role of Aldosterone in OSA and OSA-Related Hypertension

Obstructive sleep apnea (OSA) is regarded as an independent risk factor for hypertension. The possible mechanism includes oxidative stress, endothelial injury, sympathetic excitement, renin-angiotensin-aldosterone system activation, etc. Clinical studies have found that there is a high coexistence of OSA and primary aldosteronism in patients with hypertension and that elevated aldosterone levels are independently associated with OSA severity in resistant hypertension. The underlying mechanism is that aldosterone excess can exacerbate OSA through increasing overnight fluid shift and affecting the mass and function of upper airway muscles during the sleep period. Thus, a bidirectional influence between OSA and aldosterone exists and contributes to hypertension in OSA patients, especially resistant hypertension.

Reliability and Validity of Simplified Chinese STOP-BANG Questionnaire in Diagnosing and Screening Obstructive Sleep Apnea Hypopnea Syndrome

The main purpose of this study was to assess the reliability and validity of the simplified Chinese STOP-BANG Questionnaire (SBQ) as a diagnosing and screening tool for obstructive sleep apnea hypopnea syndrome (OSAHS). Two hundred and ten patients with suspected OSAHS were recruited in this study. The simplified Chinese SBQ was completed twice before and after polysomnography (PSG) monitoring. SPSS 20.0 was used to analyze the test-retest reliability, discriminant validity, comparative validity and predictive validity of the SBQ. Fourteen patients were excluded on account of fragmentary data, and valid 196 were divided into four groups: non-OSAHS group (n=28, 14.29%), mild OSAHS group (n=28, 14.29%), moderate OSAHS group (n=31, 15.81%) and severe OSAHS group (n=109, 55.61%). The test-retest coefficient for the first four items was 0.810, 0.679, 0.775, 0.963 respectively and the total score of the STOP questionnaire was 0.854. The analysis of discriminant validity revealed that there were significant differences among four groups in the total score of the SBQ and scores of item 1, 3, 7 and 8, which were also validated between patients with normal blood oxygen saturation and different degrees of hypoxemia. The SBQ evaluation showed low consistency with diagnostic gold standard PSG (κ=0.303, P<0.05). When taking apnea hypopnea index (AHI) ≥5/h, ≥15/h and ≥30/h as cut-offs to evaluate the SBQ predictive value, the areas under ROC curve were 0.77, 0.81 and 0.78, the sensitivity was 90.48%, 93.57% and 93.33%, and corresponding negative predictive values were 40.74%, 66.67% and 85.19%, respectively. It was suggested that the simplified Chinese version of SBQ had good reliability, and could distinguish the severity of OSAHS. Despite its limited diagnostic accuracy, the SBQ can be considered as an ideal tool for screening OSAHS with superior predictive validity.

Prevalence and risk factors of sleep breathing disorders in patients with acromegaly from Moscow region

Aim. Assessment of prevalence and risk factors of sleep breathing disorders in patients with acromegaly from Moscow region. Materials and methods. Cardiorespiratory monitoring was executed to 55 patients with acromegaly (18 men and 37 women): 27 patients with de novo disease, 28 patients on treatment of acromegaly (including 18 patietns with uncontrolled and 10 - with controlled acromegaly). All subgroups did not differ on sex, BMI and age. Also 24-hour monitoring of arterial blood pressure was carried out in 39 patients (12 men and 27 women, 14 patients with de novo acromegaly, 15 and 10 patients with uncontrolled and controlled acromegaly, respectively). Results and discussion. The high prevalence of sleep breathing disorders (SBD) was revealed in patients with acromegaly from Moscow Region. SBD was found in 92.6%, 83.5% and 70.0% patients with newly diagnosed, uncontrolled and controlled acromegaly, respectively. The majority of patients had severe/moderate SBD in all subgroups (78.8%, 72.2% and 60.0%, respectively). In patients with newly diagnosed and uncontrolled acromegaly index of apnea-hypopnea (31 and 38.5 respectively), number of apnoe episodes (76 and 72) and saturation level (93% and 93.5%) did not differ significantly while these parameters were better in patients with a controlled acromegaly (apnea-hypopnea index 20, apnea episodes 45.5 and saturation level 95%). The peak of desaturation was subphysiological in 91.7%, 86.7% and 77.8% of patients with newly diagnosed, uncontrolled and controlled acromegaly, respectively. Severity of SBD did not depend on GH and IGF-1 levels as well as acromegaly duration. Such all-population risk factors of SBD as BMI and age were valuable for patients with acromegaly, however gender did not matter. SBD were associated with lack of physiological decrease of systolic and diastolic night BP. Conclusion. Acromegaly per se is a strong risk factor of sleep breathing disorders. The high prevalence of sleep breathing disorders in patients with acromegaly even after achievement of control over a disease emphasized need of specialized treatment of these violations.

Obstructive Sleep Apnea Syndrome and Metabolic Diseases

With the rapid changes in lifestyle in modern society, including the high nutritional intake and reduced physical activity, the incidence of metabolic diseases has been increasing year by year. Obstructive sleep apnea syndrome (OSAS) is a sleep disorder, usually characterized by sudden pauses of breathing during sleep and an interrupted sleep rhythm. Although the pathological mechanism remains poorly understood, it has been strongly associated with metabolic diseases, including obesity, insulin resistance, type 2 diabetes mellitus (T2DM), and nonalcoholic fatty liver disease (NAFLD). In the present mini-review, we briefly summarize the connections between OSAS, obesity, T2DM, and NAFLD, which might help us to better understand the pathogenesis of human diseases.

Serum ferritin and obstructive sleep apnea-epidemiological study

PURPOSE

Ferritin is an intracellular iron storage protein and a marker of inflammation. Studies have shown that subjects with obstructive sleep apnea (OSA) have higher levels of circulating pro-inflammatory cytokines, but little is known about the association between ferritin and OSA. The aims of the study were to evaluate serum ferritin (S-Ferritin) levels in OSA patients compared to levels in the general population and also examine the effect of obesity level and treatment with positive airway pressure (PAP) on S-Ferritin levels.

METHODS

The OSA subjects (n = 796) were part of the Icelandic Sleep Apnea Cohort. The control subjects (n = 637) were randomly chosen Icelanders who participated in an epidemiological study. Propensity score (PS) methodologies were employed to minimize selection bias and strengthen causal inferences when comparing non-randomized groups. S-Ferritin levels were measured and all participants answered the same detailed questionnaire about sleep and health. Only OSA patients underwent a sleep study and were re-invited for a 2-year follow-up.

RESULTS

S-Ferritin levels were significantly higher in OSA males than controls (213.3 vs. 197.3 μg/L, p = 0.007). However, after adjusting for confounders and using our PS methodology, no significant difference was found. S-Ferritin levels were not correlated with severity of OSA, obesity level, or clinical symptoms. Also, no significant change in S-Ferritin levels was found with 2 years of PAP treatment.

CONCLUSIONS

S-Ferritin levels are comparable in OSA patients and controls and do not change consistently with obesity level or PAP treatment in our sample.

Stimulatory Effect of Intermittent Hypoxia on the Production of Corticosterone by Zona Fasciculata-Reticularis Cells in Rats

Hypoxia or intermittent hypoxia (IH) have known to alter both synthesis and secretion of hormones. However, the effect of IH on the production of adrenal cortical steroid hormones is still unclear. The aim of present study was to explore the mechanism involved in the effect of IH on the production of corticosterone by rat ZFR cells. Male rats were exposed at 12% O₂ and 88% N₂ (8 hours per day) for 1, 2, or 4 days. The ZFR cells were incubated at 37 °C for 1 hour with or without ACTH, 8-Br-cAMP, calcium ion channel blockers, or steroidogenic precursors. The concentration of plasma corticosterone was increased time-dependently by administration of IH hypoxia. The basal levels of corticosterone production in cells were higher in the IH groups than in normoxic group. IH resulted in a time-dependent increase of corticosterone production in response to ACTH, 8-Br-cAMP, progesterone and deoxycorticosterone. The production of pregnenolone in response to 25-OH-C and that of progesterone in response to pregnenolone in ZFR cells were enhanced by 4-day IH. These results suggest that IH in rats increases the secretion of corticosterone via a mechanism at least in part associated with the activation of cAMP pathway and steroidogenic enzymes.