The correlation of serum levels of leptin, leptin receptor and NO x (NO 2 (-) and NO 3 (-)) in patients with obstructive sleep apnea syndrome

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.

Distinguishing the impact of distinct obstructive sleep apnea syndrome (OSAS) and obesity related factors on human monocyte subsets

Obstructive sleep apnea syndrome (OSAS) and obesity go hand in hand in the majority of patients and both are associated with a systemic inflammation, immune disturbance and comorbidities such as cardiovascular disease. However, the unambiguous impact of OSAS and obesity on the individual inflammatory microenvironment and the immunological consequences of human monocytes has not been distinguished yet. Therefore, aim of this study was to investigate the impact of OSAS and obesity related factors on the inflammatory microenvironment by performing flow cytometric whole blood measurements of CD14/CD16 monocyte subsets in normal weight OSAS patients, patients with obesity but without OSAS, and patients with OSAS and obesity, compared to healthy donors. Moreover, explicitly OSAS and obesity related plasma levels of inflammatory mediators adiponectin, leptin, lipocalin and metalloproteinase-9 were determined and the influence of different OSAS and obesity related factors on cytokine secretion and expression of different adhesion molecules by THP-1 monocytes was analysed. Our data revealed a significant redistribution of circulating classical and intermediate monocytes in all three patient cohorts, but differential effects in terms of monocytic adhesion molecules CD11a, CD11b, CD11c, CX3CR1, CD29, CD49d, and plasma cytokine levels. These data were reflected by differential effects of OSAS and obesity related factors leptin, TNFα and hypoxia on THP-1 cytokine secretion patterns and expression of adhesion molecules CD11b and CD49d. In summary, our data revealed differential effects of OSAS and obesity, which underlines the need for a customized therapeutic regimen with respect to the individual weighting of these overlapping diseases.

The Association Between Serum/Plasma Leptin Levels and Obstructive Sleep Apnea Syndrome: A Meta-Analysis and Meta-Regression

BACKGROUND

Obstructive sleep apnea syndrome (OSAS) is associated with various adipokines. Leptin, a common adipokine, has attracted considerable attention of many researchers in recent years. So far, there has been little agreement on whether blood leptin levels differ in patients with OSAS. Thus, this meta-analysis examined the relationship between serum/plasma leptin levels and the occurrence of OSAS.

METHOD

WanFang, Embase, CNKI, Medline, SinoMed, Web of Science, and PubMed were searched for articles before March 30, 2021, with no language limitations. STATA version 11.0 and R software version 3.6.1 were used to analyze the obtained data. The weighted mean difference and correlation coefficients were used as the main effect sizes with a random-effects model and a fixed-effects model, respectively. Trial sequential analysis was conducted using dedicated software.

RESULT

Screening of 34 publications identified 45 studies that met the inclusion criteria of this meta-analysis and meta-regression. Our results suggested that plasma/serum leptin levels were remarkably higher in individuals with OSAS than in healthy individuals. Subgroup analyses were performed based on OSAS severity, ethnicity, age, body mass index, assay type, and sample source. The serum and plasma leptin levels were increased in nearly all OSAS subgroups compared to those in the corresponding control groups. Meta-regression analysis indicated that age, BMI, severity, assay approaches, study design, PSG type and ethnicity did not have independent effect on leptin levels. Furthermore, a positive relationship between the serum/plasma leptin level and apnea-hypopnea index (AHI) was found in the meta-analysis. The results of the trial sequential analysis suggested that the enrolled studies surpassed the required information size, confirming that our study findings were reliable.

CONCLUSION

Our study results demonstrate that OSAS patients have higher leptin levels in serum/plasma compared to controls, and the serum/plasma leptin level is positively correlated with AHI, especially in adults.

The role of nitric oxide (NO) levels in patients with obstructive sleep apnea-hypopnea syndrome: a meta-analysis

PURPOSE

The pathogenesis of cardiovascular disease (CVD) in patients with obstructive sleep apnea (OSA) is unclear. Several studies have suggested that CVD may be caused by oxidative stress from chronic intermittent hypoxia and associated vascular endothelial dysfunction. Oxidative stress in patients with OSA can induce endothelial cell apoptosis, aggravate vascular endothelial damage, and promote the expression of redox-sensitive genes and adhesion molecules. No meta-analysis has explored whether or not OSA is related to nitric oxide (NO).

METHOD

To assess the association between serum/plasma NO levels and OSA, we performed a meta-analysis of the literature on the subject to grade the strength of evidence.

RESULTS

OSA was significantly related to decreased serum or plasma NO levels (WMD = - 11.66, 95% CI - 17.21 to - 6.11; P < 0.01). Among the studies analyzed, there was high degree of heterogeneity (I² = 79%, P < 0.01). Sensitivity analysis showed that after omitting any single study or converting a random effects model (REM) to a fixed effects model (FEM), the main results still held.

CONCLUSIONS

This meta-analysis suggests a strong correlation between OSA and serum or plasma NO levels which may explain the link between intermittent hypoxia of OSA and risk of CVD. The strength of this finding may spur further basic and clinical research into vascular endothelial dysfunction in patients with OSA.

Relation between serum leptin levels, lipid profiles and neurocognitive deficits in Chinese OSAHS patients

OBJECTIVE

The aim of this study was to compare serum leptin, apolipoprotein A1 (ApoA1), apolipoprotein J (ApoJ) and apolipoprotein H (ApoH) levels in males with obstructive sleep apnea and hypopnea syndrome (OSAHS) to those in healthy control subjects and to examine the possible relation between neurocognitive performance and these factors/serum markers in the subjects.

METHODS

In this observational, cross-sectional study, a full-night polysomnography and sensitive neuropsychological assessment were performed on 50 newly diagnosed Chinese male patients and 30 healthy subjects. Fasting blood samples were used to measure leptin and ApoA1, ApoH and ApoJ levels using ELISA.

RESULTS

Compared with normal control subjects, OSAHS patients have significantly lower levels of ApoA1 and higher levels of leptin, ApoH and ApoJ. After adjustment for age, years of education, body mass index (BMI) and apnea-hypopnea index, leptin and ApoA1 were associated with global cognitive function, and leptin level was positively correlated with inhibition reaction time. ApoJ was negatively correlated with visual reproduction and logical memory performance. Multiple regression analysis shows that from age, BMI, education year, biomarker levels and the parameters of PSG, only the variables of leptin and education year added to the prediction of the Montreal cognitive assessment score in a statistically significant way.

CONCLUSIONS

Abnormal expression of leptin and apolipoproteins and poor performance on neuropsychological tests were observed in patients with OSAHS. There is also an association between serum leptin, ApoA1, and ApoJ levels and cognitive performance in the patients.

The correlation of serum growth differentiation factor-15 level in patients with obstructive sleep apnea

PURPOSE

Growth differentiation factor-(GDF-) is a prognostic biomarker in cardiovascular disorders (CVD). GDF-15 level was not studied in patients with obstructive sleep apnea syndrome (OSAS) before. In this study, we investigated serum GDF-15 levels in OSAS patients and compared them with healthy controls.

MATERIAL AND METHODS

Polysomnographically, confirmed forty consecutive OSAS patients (20 men and 20 women) and forty consecutive healthy controls (23 men and 17 women) were enrolled in the study. The samples in each group had similar demographic characteristics and body mass index (BMI) values.

RESULTS

In the study, no significant correlation was found about GDF-15 levels of OSAS group and healthy controls. However, there was a significant statistical correlation between age and GDF-15 level. In correlation analysis, there was not any significant correlation between age and BMI.

CONCLUSION

Although various developing biomarkers have been studied in cardiovascular disorders, GDF-15 levels have attracted a widespread interest as predictors of cardiovascular risk. GDF-15 level has not been evaluated previously in patients with OSAS. A significant statistical correlation was found between age and GDF-15 level. To reveal close relation between OSAS and GDF-15, further studies are needed with combination of GDF-15 and other biomarkers in OSAS.