Impairment of high-density lipoprotein resistance to lipid peroxidation and adipose tissue inflammation in obesity complicated by obstructive sleep apnea

Obstructive Sleep Apnea Syndrome and Obesity Indicators, Circulating Blood Lipid Levels, and Adipokines Levels: A Bidirectional Two-Sample Mendelian Randomization Study

Purpose

This investigation sought to elucidate the genetic underpinnings that connect obesity indicators, circulating blood lipid levels, adipokines levels and obstructive sleep apnea syndrome (OSAS), employing a bidirectional two-sample Mendelian randomization (MR) analysis that utilizes data derived from extensive genome-wide association studies (GWAS).

Methods

We harnessed genetic datasets of OSAS available from the FinnGen consortium and summary data of four obesity indices (including neck circumference), seven blood lipid (including triglycerides) and eleven adipokines (including leptin) from the IEU OpenGWAS database. We primarily utilized inverse variance weighted (IVW), weighted median, and MR-Egger methods, alongside MR-PRESSO and Cochran's Q tests, to validate and assess the diversity and heterogeneity of our findings.

Results

After applying the Bonferroni correction, we identified significant correlations between OSAS and increased neck circumference (Odds Ratio [OR]: 3.472, 95% Confidence Interval [CI]: 1.954-6.169, P= 2.201E-05) and decreased high-density lipoprotein (HDL) cholesterol levels (OR: 0.904, 95% CI: 0.858-0.952, P= 1.251E-04). Concurrently, OSAS was linked to lower leptin levels (OR: 1.355, 95% CI: 1.069-1.718, P= 0.012) and leptin receptor levels (OR: 0.722, 95% CI: 0.530-0.996, P= 0.047). Sensitivity analyses revealed heterogeneity in HDL cholesterol and leptin indicators, but further multiplicative random effects IVW method analysis confirmed these correlations as significant (P< 0.05) without notable heterogeneity or horizontal pleiotropy in other instrumental variables.

Conclusion

This investigation compellingly supports the hypothesis that OSAS could be a genetic predisposition for elevated neck circumference, dyslipidemia, and adipokine imbalance. These findings unveil potential genetic interactions between OSAS and metabolic syndrome, providing new pathways for research in this domain. Future investigations should aim to delineate the specific biological pathways by which OSAS impacts metabolic syndrome. Understanding these mechanisms is critical for developing targeted prevention and therapeutic strategies.

Association of Tumor Necrosis Factor-Alpha, Interleukin-1β, Interleukin-8, and Interferon-γ with Obstructive Sleep Apnea in Both Children and Adults: A Meta-Analysis of 102 Articles

Background: Cytokines may have a significant impact on sleep regulation. In this meta-analysis, we present the serum/plasma levels of tumor necrosis factor-alpha (TNF-α), interleukin (IL)-8, IL-1β, and interferon-gamma (IFN-γ) in both children and adults with obstructive sleep apnea (OSA) in comparison to controls. Methods: Four electronic databases were systematically searched (PubMed, Web of Science, Scopus, and Cochrane Library) through 19 October 2023, without any restrictions on language, date, age, and sex. We used Review Manager version 5.3 to perform meta-analysis and presented the data as standardized mean difference (SMD) and 95% confidence interval (CI) values to evaluate the relationships between the levels of cytokines and OSA. Results: A total of 102 articles (150 independent studies) were included in the meta-analysis. The pooled SMDs in adults were 1.42 (95%CI: 1.11, 1.73; p < 0.00001), 0.85 (95%CI: 0.40, 1.31; p = 0.0002), 0.69 (95%CI: 0.22, 1.16; p = 0.004), and 0.39 (95%CI: -0.37, 1.16; p = 0.31) for TNF-α, IL-8, IL-1β, and IFN-γ, respectively. The pooled SMDs in children were 0.84 (95%CI: 0.35, 1.33; p = 0.0008), 0.60 (95%CI: 0.46, 0.74; p < 0.00001), 0.25 (95%CI: -0.44, 0.93; p = 0.49), and 3.70 (95%CI: 0.75, 6.65; p = 0.01) for TNF-α, IL-8, IL-1β, and IFN-γ, respectively. Conclusions: The levels of proinflammatory cytokines of TNF-α, IL-8, and IL-1β in adults, and TNF-α, IL-8, and IFN-γ in children with OSA, are significantly higher than those in controls.

Established and potential cardiovascular risk factors in metabolic syndrome: Effect of bariatric surgery

PURPOSE OF REVIEW

The aim of this review was to provide an overview of the role of novel biomarkers in metabolic syndrome, their association with cardiovascular risk and the impact of bariatric surgery on these biomarkers.

RECENT FINDINGS

Metabolic syndrome encompasses an intricate network of health problems, and its constituents extend beyond the components of its operational definition. Obesity-related dyslipidaemia not only leads to quantitative changes in lipoprotein concentration but also alteration in qualitative composition of various lipoprotein subfractions, including HDL particles, rendering them proatherogenic. This is compounded by the concurrent existence of obstructive sleep apnoea (OSA) and nonalcoholic fatty liver disease (NAFLD), which pave the common pathway to inflammation and oxidative stress culminating in heightened atherosclerotic cardiovascular disease (ASCVD) risk. Bariatric surgery is an exceptional modality to reverse both conventional and less recognised aspects of metabolic syndrome. It reduces the burden of atherosclerosis by ameliorating the impact of obesity and its related complications (OSA, NAFLD) on quantitative and qualitative composition of lipoproteins, ultimately improving endothelial function and cardiovascular morbidity and mortality.

SUMMARY

Several novel biomarkers, which are not traditionally considered as components of metabolic syndrome play a crucial role in determining ASCVD risk in metabolic syndrome. Due to their independent association with ASCVD, it is imperative that these are addressed. Bariatric surgery is a widely recognized intervention to improve the conventional risk factors associated with metabolic syndrome; however, it also serves as an effective treatment to optimize novel biomarkers.

Effects of oral appliances on serum cytokines in adults with obstructive sleep apnea: a systematic review

PURPOSE

This review aimed to evaluate the effects of oral appliance (OA) therapy on serum inflammatory cytokines in adults diagnosed with obstructive sleep apnea (OSA).

METHODS

Seven electronic databases and partial gray literature were searched without restrictions through March 2021. Articles evaluating the levels of serum inflammatory cytokines in patients with OSA after OA treatment were included. The risk of bias (RoB) was assessed using the before-and-after tool or RoB 2.0. The level of certainty was assessed using the GRADE tool.

RESULTS

Five studies met the eligibility criteria. One was a randomized clinical trial (RCT), while four were non-randomized clinical trials (NRCTs). Among the studies, C-reactive protein (CRP), IL-6, IL-10, IL-1β, and tumor necrosis factor α (TNF-α) were investigated. The RCT reported no significant differences in marker levels after 2 months of OA therapy, while the NRCTs showed improvement on CRP, TNF-α, and IL-1β levels after longer follow-up periods. The RoB was evaluated as showing some concern in the RCT. Three NRCTs presented good RoB, and one showed a fair RoB. The level of certainty was graded as moderate quality for inflammatory marker levels assessed in the RCT The levels of certainty evaluated in NRCTs were classified as very low.

CONCLUSIONS

Although limited, existing scientific evidence showed that OA therapy may improve serum cytokine levels in adults with OSA. However, short treatment periods are not effective in reducing markers of systemic inflammation which may require extended time and a decrease of in apneic events to improve.

Bariatric Surgery-induced High-density Lipoprotein Functionality Enhancement Is Associated With Reduced Inflammation

BACKGROUND

Emerging evidence suggests an association between impaired high-density lipoprotein (HDL) functionality and cardiovascular disease (CVD). HDL is essential for reverse cholesterol transport (RCT) and reduces inflammation and oxidative stress principally via paraoxonase-1 (PON1). RCT depends on HDL's capacity to accept cholesterol (cholesterol efflux capacity [CEC]) and active transport through ATP-binding cassette (ABC) A1, G1, and scavenger receptor-B1 (SR-B1). We have studied the impact of Roux-en-Y gastric bypass (RYGB) in morbidly obese subjects on RCT and HDL functionality.

METHODS

Biomarkers associated with increased CVD risk including tumour necrosis factor-α (TNF-α), high-sensitivity C-reactive protein (hsCRP), myeloperoxidase mass (MPO), PON1 activity, and CEC in vitro were measured in 44 patients before and 6 and 12 months after RYGB. Overweight but otherwise healthy (mean body mass index [BMI] 28 kg/m2) subjects acted as controls. Twelve participants also underwent gluteal subcutaneous adipose tissue biopsies before and 6 months after RYGB for targeted gene expression (ABCA1, ABCG1, SR-B1, TNF-α) and histological analysis (adipocyte size, macrophage density, TNF-α immunostaining).

RESULTS

Significant (P < 0.05) improvements in BMI, HDL-cholesterol, hsCRP, TNF-α, MPO mass, PON1 activity, and CEC in vitro were observed after RYGB. ABCG1 (fold-change, 2.24; P = 0.005) and ABCA1 gene expression increased significantly (fold-change, 1.34; P = 0.05). Gluteal fat adipocyte size (P < 0.0001), macrophage density (P = 0.0067), and TNF-α immunostaining (P = 0.0425) were reduced after RYBG and ABCG1 expression correlated inversely with TNF-α immunostaining (r = -0.71; P = 0.03).

CONCLUSION

RYGB enhances HDL functionality in association with a reduction in adipose tissue and systemic inflammation.

Correlation of Dyslipidemia and Inflammation With Obstructive Sleep Apnea Severity

Introduction: Obstructive sleep apnea (OSA) is a serious condition linked with various metabolic disorders and associated with increased all-cause and cardiovascular mortality. Although the potential mechanisms of pathophysiological processes related to OSA are relatively well known, the data regarding the correlation between obstructive sleep apnea, dyslipidemia, and systemic inflammation are still inconclusive.

Methods: The study was conducted as a retrospective cohort study including 328 patients with newly diagnosed obstructive sleep apnea during the period between April 2018, and May 2020, in University Clinical Hospital Center “Bezanijska kosa”, Belgrade, Serbia. Polysomnography was performed in all patients according to the protocol. Numerous demographic, antropometric, laboratory, and clinical data were correlated to Apnea-Hypopnea Index (AHI) as a dependent variable, with a particular review on the relation between lipid abnormalities, inflammatory parameters, and obstructive sleep apnea severity. Multivariate logistic regression model was used to assess predictors of severe OSA (AHI ≥30 per hour).

Results: A total of 328 patients were included in the study. The mean age of the patients was 54.0 ± 12.5 years and more than two-thirds were male (68.8%). The majority of the patients had an AHI of at least 30 events per hour. Patients with severe OSA were more frequently male, obese, hypertensive and hyperlipidemic, and had increased neck circumference (both male and female patients). One hundred and thirty-two patients had metabolic syndrome. Patients with severe OSA more frequently had metabolic syndrome and significantly higher levels of glucose, creatinine, uric acid, AST, ALT, CK, microalbumine/creatinine ratio, triglyceride, total cholesterol, HDL, total cholеsterol to HDL‐C ratio, CRP, and ESR. In the multivariate linear regression model with AHI (≥30 per hour) as a dependent variable, of demographic and clinical data, triglycerides ≥1.7 mmol/L and CRP >5 mg/L were significantly associated with AHI≥30 per hour.

Conclusion: The present study on 328 patients with newly diagnosed obstructive sleep apnea revealed significant relation of lipid abnormalities, inflammatory markers, and other clinically important data with obstructive sleep apnea severity. These results can lead to a better understanding of the underlying pathophysiological processes and open the door to a new world of potentially useful therapeutic modalities.

Paraoxonase-1 Concentrations in Obstructive Sleep Apnoea: A Systematic Review and Meta-Analysis

Obstructive sleep apnoea (OSA) is characterized by overproduction of reactive oxygen species and oxidative stress. The antioxidant enzyme paraoxonase-1 (PON-1) may be useful for monitoring the antioxidant defence systems and the effect of treatments in OSA patients. We investigated, by means of systematic review and meta-analysis, the serum concentrations of PON-1 in OSA patients and non-OSA controls. A literature search was conducted in PubMed, Web of Science, Scopus and Google Scholar databases, from the outset to November 2021, utilizing the terms: “paraoxonase” or “PON” or “paraoxonase-1” or “PON-1” and “obstructive sleep apnoea syndrome” or “OSAS” or “OSA”. Eleven studies in 429 OSA patients and 258 non-OSA controls were involved in the meta-analysis. The pooled serum PON-1 concentrations were significantly lower in OSA (standardized mean difference (SMD) = −0.70, 95% CI −1.13 to −0.28; p = 0.001). Despite the extreme between-study heterogeneity, the SMD values were not substantially affected by the sequential omission of individual studies. There was no publication bias. Our systematic review and meta-analysis supports the presence of an impaired antioxidant defence system in OSA, possibly the consequence of intermittent hypoxia. Further studies are required to determine the clinical use of PON-1 measurements for risk stratification and monitoring in OSA patients.

The role of abnormalities of lipoproteins and HDL functionality in small fibre dysfunction in people with severe obesity

Obesity and associated dyslipidemia may contribute to increased cardiovascular disease. Obesity has also been associated with neuropathy. We have investigated presence of peripheral nerve damage in patients with severe obesity without type 2 diabetes and the status of metabolic syndrome and lipoprotein abnormalities. 47participants with severe obesity and 30 age-matched healthy controls underwent detailed phenotyping of neuropathy and an assessment of lipoproteins and HDL-functionality. Participants with severe obesity had a higher neuropathy symptom profile, lower sural and peroneal nerve amplitudes, abnormal thermal thresholds, heart rate variability with deep breathing and corneal nerve parameters compared to healthy controls. Circulating apolipoprotein A1 (P = 0.009), HDL cholesterol (HDL-C) (P < 0.0001), cholesterol efflux (P = 0.002) and paroxonase-1 (PON-1) activity (P < 0.0001) were lower, and serum amyloid A (SAA) (P < 0.0001) was higher in participants with obesity compared to controls. Obese participants with small nerve fibre damage had higher serum triglycerides (P = 0.02), lower PON-1 activity (P = 0.002) and higher prevalence of metabolic syndrome (58% vs. 23%, P = 0.02) compared to those without. However, HDL-C (P = 0.8), cholesterol efflux (P = 0.08), apoA1 (P = 0.8) and SAA (P = 0.8) did not differ significantly between obese participants with and without small nerve fibre damage. Small nerve fibre damage occurs in people with severe obesity. Patients with obesity have deranged lipoproteins and compromised HDL functionality compared to controls. Obese patients with evidence of small nerve fibre damage, compared to those without, had significantly higher serum triglycerides, lower PON-1 activity and a higher prevalence of metabolic syndrome.

Evaluation of Blood Levels of C-Reactive Protein Marker in Obstructive Sleep Apnea: A Systematic Review, Meta-Analysis and Meta-Regression

(1) Introduction: High sensitivity C-reactive protein (hs-CRP) and CRP are inflammatory biomarkers associated with several inflammatory diseases. In both pediatric and adult individuals with Obstructive Sleep Apnea (OSA) higher hs-CRP and CRP were observed, compared to controls. With the present systematic review, meta-analysis and meta-regression we expand upon previous meta-analyses in four ways: (1) We included 109 studies (96 in adults and 13 in children); (2) we reported subgroup and meta-regression analyses in adults with OSA compared to controls on the serum and plasma levels of hs-CRP; (3) we reported subgroup and meta-regression analyses in adults with OSA compared to controls on the serum and plasma levels of CRP; (4) we reported serum and plasma levels of both hs-CRP and CRP in children with OSA, always compared to controls. (2) Materials and Methods: The PubMed/Medline, Scopus, Cochrane Library, and Web of Science databases were searched to retrieve articles published until 31 May 2020, with no restrictions. The data included basic information involving the first author, publication year, country of study, ethnicity of participants in each study, age, BMI, and AHI of both groups, and mean and standard deviation (SD) of plasma and serum levels of CRP and hs-CRP. (3) Results: A total of 1046 records were retrieved from the databases, and 109 studies were selected for the analysis (96 studies reporting the blood levels of hs-CRP/CRP in adults and 13 studies in children). For adults, 11 studies reported plasma hs-CRP, 44 serum hs-CRP, 9 plasma CRP, and 32 serum CRP levels. For children, 6 studies reported plasma hs-CRP, 4 serum hs-CRP, 1 plasma CRP, and 2 serum CRP levels. Compared to controls, the pooled MD of plasma hs-CRP levels in adults with OSA was 0.11 mg/dL (p < 0.00001). Compared to controls, the pooled MD of serum hs-CRP levels in adults with OSA was 0.09 mg/dL (p < 0.00001). Compared to controls, the pooled MD of plasma CRP levels in adults with OSA was 0.06 mg/dL (p = 0.72). Compared to controls, the pooled MD of serum CRP levels in adults with OSA was 0.36 mg/dL (p < 0.00001). Compared to controls, the pooled MD of plasma hs-CRP, serum hs-CRP, plasma hs-CRP, and serum hs-CRP in children with OSA was 1.17 mg/dL (p = 0.005), 0.18 mg/dL (p = 0.05), 0.08 mg/dL (p = 0.10), and 0.04 mg/dL (p = 0.33), respectively. The meta-regression showed that with a greater apnea-hypapnea index (AHI), serum hs-CRP levels were significantly higher. (4) Conclusions: The results of the present systematic review, meta-analysis and meta-regression showed that compared to healthy controls plasma and serum levels of hs-CRP and serum CRP level were higher in adults with OSA; for children, and compared to controls, just plasma hs-CRP levels in children with OSA were higher.

Is the Oxidative Stress in Obstructive Sleep Apnea Associated With Cardiovascular Complications?-Systematic Review

Obstructive sleep apnea (OSA) is a prevalent, underdiagnosed disease and is considered an independent risk factor for cardiovascular disease. The exact mechanism of cardiovascular complications (CVC) development as a complication of OSA is not entirely understood. Oxidative stress is suspected to be the essential factor in initiating various comorbidities in OSA. Biomarkers of nonenzymatic lipid and protein peroxidation, DNA repair and antioxidant capabilities measured in serum, plasma and urine are frequently used to assess the presence of oxidative stress. We conducted a systematic review and quality assessment of available observational analytic studies to determine whether there is an association between oxidative stress and OSA in patients with prevalent CV disease compared to (a) patients with prevalent CV disease but no OSA, (b) patients with prevalent CV disease and less severe OSA and (c) patients with OSA and no overt CV disease. This systematic review demonstrated that, while oxidative stress is associated with OSA, there was no clear difference in the severity of oxidative stress between OSA patients with or without cardiovascular complications.

Association between tumor necrosis factor alpha and obstructive sleep apnea in adults: a meta-analysis update

BACKGROUND

Tumor necrosis factor-α (TNF-α) has been reported to play a part in the development of obstructive sleep apnea (OSA) and its complications. However, the relationship between TNF-α and OSA still remains inconclusive. We aimed to systematically review and synthesize studies published to date on association between the two in adults.

METHODS

We searched for English-language articles containing original human data from case-control study studies in adults≥18 years of age. The selection criteria were set according to the PICOS framework. Articles were independently reviewed by three investigators. Data regarding demographics, clinical characteristics, and TNF-α levels were obtained. A random-effects model was applied to evaluate the overall effect sizes by calculating standard mean difference (SMD) and its 95% confidence intervals (CIs).

RESULTS

Of 393 identified abstracts, 50 articles (3503 OSA patients and 3379 health controls) were ultimately included in this meta-analysis. The results indicated that the TNF-α level in patients with OSA was 1.77 (95%CI, 1.37 to 2.17, I² = 97.8%, P < 0.0001) times higher than in the control group. Subgroup analyses showed a positive correlation between the level of TNF-α and OSA severity. According to meta-regression, we noted that aging significantly predicted an increased effect size of TNF-α level in OSA patients (P < 0.007).

CONCLUSION

This study identified a significant association between OSA and elevated TNF-α level in adults. Meanwhile, TNF-α levels were consistently correlated with severity of OSA, which indicated it might be a promising biomarker for the development of OSA. However, well-designed, large-scale, case-control cohorts are needed to better understand the relationship of TNF-α in the context of adult OSA.

Metabolic and cardiovascular outcomes of bariatric surgery

PURPOSE OF REVIEW

Bariatric surgery is an effective therapy for morbid obesity that also improves weight-related metabolic parameters and reduces morbidity and mortality. The purpose of this review is to consolidate our current understanding of metabolic, macrovascular and microvascular benefits of bariatric surgery and to provide an update.

RECENT FINDINGS

Early resolution of insulin resistance and type 2 diabetes mellitus (T2DM) varies by type of bariatric surgery and appears to be mediated by changes in secretion of gut hormones, metabolism of bile acids, expression of glucose transporters and the gut microbiome. Dyslipidaemia, atherosclerosis, microvascular complications of obesity and diabetes, systemic and tissue-level inflammation show evidence of regression and hypertension improves significantly after bariatric surgery.

SUMMARY

Bariatric surgery leads to improvements in obesity-related metabolic comorbidities such as dyslipidaemia, HDL functionality, hypertension, T2DM, insulin resistance and inflammation. It slows the atherosclerotic process and reduces cardiovascular and all-cause mortality. Recent data have demonstrated regression of the microvascular complications of obesity and diabetes including the regeneration of small nerve fibres. The magnitude of change in short-term metabolic effects depends on the surgical procedure whilst longer term effects are related to the amount of sustained excess weight loss.

Pro-inflammatory HDL in women with obesity and nonalcoholic steatohepatitis

BACKGROUND

Individuals with non-alcoholic fatty liver disease (NAFLD), which includes non-alcoholic steatohepatitis (NASH), are at increased risk for cardiovascular events, independent of traditional risk factors. Limited data on pro-inflammatory high density lipoprotein (HDL) in NASH exists in the literature. We hypothesized that HDL from individuals with NASH would be more pro-inflammatory than HDL from individuals without NASH.

METHODS

Study participants were individuals with obesity who had undergone bariatric surgery with wedge liver biopsy. Using HDL isolated from serum obtained from study participants at the time of surgery, HDL-elicited macrophage cytokine expression (TNF-α, IL-1β, and IL-6) from THP-1 macrophages, HDL-associated receptor expression (ABCA1 and ABCG1) from apolipoprotein E deficient (apo E^-/-) mouse peritoneal macrophages, and isolevuglandin (isoLG) modified HDL were measured.

RESULTS

11 women with NASH and 15 women without NASH were included in the study. Both TNF-α (P = 0.032) and IL-1β (P = 0.029) were significantly more expressed by THP-1 macrophages exposed to HDL from women with NASH compared to women without NASH. ABCA1 and ABCG1 expression by apo E^-/- mouse peritoneal macrophages was not significantly different when exposed to HDL from either women with NASH or women without NASH. IsoLG-modified HDL isolated from the serum of women with NASH trended higher than women without NASH.

CONCLUSION

Our study suggests a more pro-inflammatory HDL in women with obesity and NASH compared to women with obesity and without NASH.

Alterations in Parafoveal and Optic Disc Vessel Densities in Patients with Obstructive Sleep Apnea Syndrome

Purpose

To analyze the effects of obstructive sleep apnea syndrome (OSAS) on ocular parameters and determine the alterations in macular vasculature by optical coherence tomography-angiography (OCT-A) in patients with different stages of OSAS.

Methods

All the participants underwent a full ophthalmological examination. Using the macular OCT-A scans, the retinal peripapillary capillary plexus (RPCP), foveal avascular zone (FAZ), and superficial and deep vessel densities were recorded.

Results

A total of 77 patients (154 eyes) with OSAS and 27 control cases (54 eyes) were included in this prospective study. Of the OSAS patients, 27 had mild, 24 had moderate, and 26 had severe disease. The intraocular pressure (IOP) values were significantly higher in the severe OSAS group than the control cases (p = 0.001). The average retinal nerve fiber layer (RNFL) thickness and the RNFL thickness of the temporal and inferior quadrants were significantly lower in the severe OSAS group compared with the control cases (p = 0.001). The average retinal nerve fiber layer (RNFL) thickness and the RNFL thickness of the temporal and inferior quadrants were significantly lower in the severe OSAS group compared with the control cases (p = 0.001). The average retinal nerve fiber layer (RNFL) thickness and the RNFL thickness of the temporal and inferior quadrants were significantly lower in the severe OSAS group compared with the control cases (

Conclusions

Decreased vascular structures and increased FAZ may also be associated with the disease severity in OSAS and may be the main pathophysiological mechanisms in ocular alterations, which should be investigated in further studies.

Tumor necrosis factor alpha is a promising circulating biomarker for the development of obstructive sleep apnea syndrome: a meta-analysis

Obstructive sleep apnea syndrome (OSAS) is a chronic inflammatory disorder. The relationship between tumor necrosis factor alpha (TNF-alpha) and OSAS has been widely evaluated, but the results thus far remain inconclusive. We thereby decided to quantify the changes of TNF-alpha between OSAS patients and controls by a meta-analysis. This study complies with the MOOSE guidelines. Two reviewers independently searched articles and abstracted relevant data. In total, 47 articles (59 studies) were analyzed, including 2857 OSAS patients and 2115 controls. Overall, OSAS patients had a significantly higher level of circulating TNF-alpha than controls (weighted mean difference [WMD]: 9.66 pg/mL, 95% confidence interval [CI]: 8.66 to 11.24, P<0.001), but with significant heterogeneity (I²: 99.7%). After adjusting for potential missing studies, the overall estimate was weakened but still significant (filled WMD: 2.63 pg/mL, 95% CI: 2.56 to 2.70, P<0.001). When studies were stratified by OSAS severity, the changes in circulating TNF-alpha between patients and controls increased gradually with the more severe grades of OSAS. In patients with mild, mild-to-moderate, moderate, moderate-to-severe and severe OSAS, circulating TNF-alpha was higher than respective controls by 0.99, 1.48. 7.79, 10.08 and 8.85 pg/mL, with significant heterogeneity (I²: 91.2%, 74.5%, 97.6%, 99.0% and 98.1%). In conclusion, our findings demonstrated that circulating TNF-alpha was significantly higher in OSAS patients than in controls, and this difference became more pronounced with the more severe grades of OSAS, indicating that TNF-alpha might be a promising circulating biomarker for the development of OSAS.

Adiponectin concentration data improve the estimation of atherosclerotic risk in normal and in overweight subjects

BACKGROUND

The combinations of adipokines and body mass parameters to estimate carotid atherosclerotic disease have not been completely delineated.

OBJECTIVE

To test the combinations of well-established, easily accessible body mass indices and circulating biomarkers to identify increased carotid intima-media thickness (cIMT) in a primary prevention setting.

DESIGN AND PATIENTS

In a cross-sectional analysis of 339 asymptomatic individuals with no history of cardiovascular events, inflammatory and insulin sensitivity biomarkers as well as adipokine levels were measured and combined with body mass parameters to evaluate the best marker for increased cIMT.

RESULTS

As isolated parameters, body mass index (BMI) and adiponectin best identified abnormal cIMT (P = .04). Adiponectin levels were also linked to the relationship between BMI and cIMT (β = 0.0371; P = .01). Twenty-nine individuals with increased cIMT were missed by BMI alone but detected by combining BMI and adiponectin measurements. When compared with BMI alone, the combination of adiponectin plus BMI improved the c-statistic (0.549-0.567) and the integrated discrimination improvement index (0.01725; P = .021). Segregation of individuals by the combined use of BMI + adiponectin is associated with significant differences in insulin sensitivity, glomerular filtration rate, systemic inflammatory activity, dyslipidaemia and cIMT.

CONCLUSIONS

Combining plasma adiponectin measurements and BMI improves estimation of cIMT as compared to anthropometric parameters.

Slim Body Weight Is Highly Associated With Enhanced Lipoprotein Functionality, Higher HDL-C, and Large HDL Particle Size in Young Women

There has been no information about the correlations between body weight distribution and lipoprotein metabolism in terms of high-density lipoproteins-cholesterol (HDL-C) and cholesteryl ester transfer protein (CETP). In this study, we analyzed the quantity and quality of HDL correlations in young women (21.5 ± 1.2-years-old) with a slim (n = 21, 46.2 ± 3.8 kg) or plump (n = 30, 54.6 ± 4.4 kg) body weight. Body weight was inversely correlated with the percentage of HDL-C in total cholesterol (TC). The plump group showed 40% higher body fat (26 ± 3 %) and 86% more visceral fat mass (VFM, 1.3 ± 0.3 kg) than the slim group, which showed 18 ± 2% body fat and 0.7 ± 0.2 kg of VFM. Additionally, the plump group showed 20% higher TC, 58% higher triglyceride (TG), and 12% lower HDL-C levels in serum. The slim group showed 34% higher apoA-I but 15% lower CETP content in serum compared to the plump group. The slim group showed a 13% increase in particle size and 1.9-fold increase in particle number with enhanced cholesterol efflux activity. Although the plump group was within a normal body mass index (BMI) range, its lipid profile and lipoprotein properties were distinctly different from those of the slim group in terms of CETP mass and activity, HDL functionality, and HDL particle size.

Hypercholesterolaemia - practical information for non-specialists

Hypercholesterolaemia is amongst the most common conditions encountered in the medical profession. It remains one of the key modifiable cardiovascular risk factors and there have been recent advances in the risk stratification methods and treatment options available. In this review, we provide a background into hypercholesterolaemia for non-specialists and consider the merits of the different risk assessment tools available. We also provide detailed considerations as to: i) when to start treatment, ii) what targets to aim for and iii) the role of low density lipoprotein cholesterol.

Tanshinone IIA protects against chronic intermittent hypoxia-induced myocardial injury via activating the endothelin 1 pathway

Tanshinone IIA (Tan IIA) may exert significant protective effects against heart oxidative stress damage in obstructive sleep apnoea (OSA) syndrome. Chronic intermittent hypoxia (CIH)-triggered left ventricular dysfunction is used in a rat model to mimic CIH in OSA patients. 48 rats were randomly divided into three groups: normal control (NC) group, CIH group and CIH+Tan IIA group with 16 rats in each group. At the end of experiment (day 21), the blood pressure, Plasma ET-1 and NO content, hemodynamic indexes, heart histology, myocardial apoptosis as well as the expression of eNOS, ET-1, ET_A receptor and ET_B receptor were compared among different groups. Tan IIA was able to inhibit the increase of blood pressure induced by CIH. Meanwhile, rat cardiac function in Tan IIA group was evaluated by hemodynamic indexes, histopathological examination. Higher ventricular eNOS activity was induced by Tan IIA with a reduction in both ET-1 and ET_A receptor expression. However, Tan IIA largely inhibited the decrease of ET_B receptor expression. This study demonstrated that Tan IIA has the potential to benefit rat heart against CIH via endothelin system.

Correction of intermittent hypoxia reduces inflammation in obese subjects with obstructive sleep apnea

BACKGROUND

In obese subjects with obstructive sleep apnea (OSA), chronic intermittent hypoxia (CIH) may be linked to systemic and adipose tissue inflammation.

METHODS

We obtained abdominal subcutaneous adipose tissue biopsies from OSA and non-OSA obese (BMI > 35) subjects at baseline and after 24 weeks (T1) of weight-loss intervention plus continuous positive airway pressure (c-PAP) or weight-loss intervention alone, respectively. OSA subjects were grouped according to good (therapeutic) or poor (subtherapeutic) adherence to c-PAP.

RESULTS

At baseline, anthropometric and metabolic parameters, serum cytokines, and adipose tissue mRNA levels of obesity-associated chemokines and inflammatory markers were not different in OSA and non-OSA subjects. At T1, body weight was significantly reduced in all groups. Serum concentrations of IL-2, IL-4, IL-6, MCP-1, PDGFβ, and VEGFα were reduced by therapeutic c-PAP in OSA subjects and remained unaltered in non-OSA and subtherapeutic c-PAP groups. Similarly, adipose tissue mRNA levels of macrophage-specific (CD68, CD36) and ER stress (ATF4, CHOP, ERO-1) gene markers, as well as of IL-6, PDGFβ, and VEGFα, were decreased only in the therapeutic c-PAP group.

CONCLUSION

CIH does not represent an additional factor increasing systemic and adipose tissue inflammation in morbid obesity. However, in subjects with OSA, an effective c-PAP therapy improves systemic and obesity-associated inflammatory markers.

FUNDING

Ministero dell'Università e della Ricerca and Progetti di Rilevante Interesse Nazionale.

Weight loss and metabolic outcomes of bariatric surgery in men versus women - A matched comparative observational cohort study

BACKGROUND

Despite the high prevalence of morbid obesity, the global frequency of bariatric surgery in men is significantly lower than in women. It is unclear if this is due to the perception of poorer outcomes in men.

OBJECTIVES

Compare weight loss and metabolic outcomes in men vs. women after bariatric surgery.

SETTING

University teaching hospital in North West England.

METHODS

We performed an observational cohort analysis of 79 men matched to 79 women for baseline age (± 5 years), body mass index (BMI; ± 2 kg/m(2)), bariatric procedure (69 gastric bypass and 10 sleeve gastrectomy each), type 2 diabetes (33 each), and continuous positive airway pressure (CPAP) therapy for obstructive sleep apnoea (OSA; 40 each).

RESULTS

Overall mean (95% confidence interval) reduction in BMI was 17.5 (15.7-19.4) kg/m(2) (P<0.001) at 24 months. There was no significant difference between men and women in mean percentage excess BMI loss (65.8% vs. 72.9%) at 24 months. Likewise, there were significant reductions in blood pressure, glycosylated haemoglobin and total cholesterol-to-high density lipoprotein cholesterol overall but no significant gender differences. Postoperatively, 77.5% of men and 90.0% of women with OSA discontinued CPAP therapy (non-significant).

CONCLUSIONS

Weight loss and metabolic outcomes after bariatric surgery are of similar magnitude in men compared to women. The use of bariatric surgery in eligible men should be encouraged.