Serum YKL-40 concentrations are elevated and correlated with disease severity in patients with obstructive sleep apnea syndrome

Osteoprotegerin, Chitinase 3-like Protein 1, and Cardiotrophin-1 as Potential Biomarkers of Obstructive Sleep Apnea in Adults-A Case-Control Study

Obstructive sleep apnea (OSA) is a prevalent, underdiagnosed disease and is considered a risk factor for cardiovascular diseases, depression, accidents, and stroke. Recent clinical practice guidelines for OSA expressed the need for a new clinical tool that establishes the Apnea-Hypopnea Index (AHI) to determine the disease burden. The serum and plasma concentrations of Osteoprotegerin (OPG), Chitinase 3-like protein 1 (YKL-40), and Cardiotrophin-1 (CT-1) in 80 subjects-52 OSA patients, 27 moderate (15 ≤ AHI ˂ 30) and 25 severe (AHI ≥ 30), and 28 non-OSA controls (AHI 0-5)-were determined. Moreover, the Total Oxidative Status (TOS), Total Antioxidative Status (TAS), and Oxidative Stress Index (OSI) were assessed in the serum and plasma to evaluate whether the severity of OSA and the concentrations of OPG, YKL-40, and CT-1 correlate with the oxidative/reductive status. The serum and plasma concentrations of YKL-40 and CT-1 were higher in the OSA group, whereas the serum and plasma concentrations of OPG were lower compared to the control group. The concentrations of OPG, YKL-40, and CT-1 in the serum and plasma correlated with AHI; however, a better correlation of the concentrations was obtained for the above-mentioned proteins in the plasma. The concentrations of YKL-40 and CT-1 in the serum and OPG in the plasma show better diagnostic capabilities for moderate and severe OSA than the concentrations of YKL-40 and CT-1 in the plasma and the concentrations of OPG in the serum.

Inflammatory markers in children with obstructive sleep apnea syndrome

Objective

To evaluate serum inflammatory markers of YKL-40, Interleukin-6 (IL-6), Interleukin-8(IL-8), Interleukin-10(IL-10), TNF-α(tumor necrosis factor-α), and CRP (C-reactive protein) in children with and without OSAS.

Methods

The ELISA technique has been used to identify the concentration of inflammatory markers such as YKL-40, IL-6, IL-8, IL-10, TNF-α, and CRP in the serum of 83 children with OSAS and 83 children without OSAS.

Results

Serum levels of YKL-40, IL-6, IL-8, and IL-10 were found to be increased in children with OSAS. YKL-40 was found to be positively correlated with IL-6 and IL-8, and negatively correlated with IL-10. At the same time,YKL-40 was also found to be positively correlated with OAHI and LoSpO2% in OSAS group. IL-8 was positively correlated with OAHI whereas IL-10 was positively correlated with LoSpO2.

Conclusion

Children with OSAS are in a systemic inflammatory state. YKL-40 together with IL-8 may act as serum inflammatory markers and provide an indication for the diagnosis of children with OSAS.

The serum YKL-40 level is a potential biomarker for OSAHS: a systematic review and meta-analysis

PURPOSE

Several studies have reported that serum YKL-40 level was elevated in patients with obstructive sleep apnea hypopnea syndrome (OSAHS). However, most of these studies had relatively small sample sizes and the results were inconsistent. Therefore, a meta-analysis was conducted to determine the potential role of serum YKL-40 level in OSAHS.

METHODS

A systematic literature search was performed in several databases to identify eligible studies involving the relationship between serum YKL-40 level and OSAHS. The standardized mean difference (SMD) with its 95% confidence interval (CI) was calculated to determine the effect sizes.

RESULTS

Five eligible articles were extracted in this meta-analysis. The pooled results demonstrated that the serum YKL-40 level was significantly higher in OSAHS patients compared with their non-OSAHS controls (SMD 1.03, 95% CI 0.46, 1.59, I² = 87%, P = 0.0004). The subgroup analysis showed that Asian (SMD 1.81, 95% CI 1.41, 2.21, I² = 0%, P < 0.00001) and Caucasian (SMD 0.67, 95% CI 0.39, 0.96, I² = 0%, P < 0.00001) patients with OSAHS had higher serum YKL-40 levels than their non-OSAHS controls. YKL-40 level in serum was increased in OSAHS patients with BMI < 28 (SMD 1.81, 95% CI 1.41, 2.21, I² = 0%, P < 0.00001), as well as in patients with BMI ≥ 28 (SMD 0.57, 95% CI 0.33, 0.81, I² = 0%, P < 0.00001). In addition, OSAHS patients with cardiac complications had a higher serum YKL-40 level compared with those patients without cardiac complications (SMD 0.80, 95% CI 0.32, 1.28, I² = 67%, P = 0.001).

CONCLUSIONS

This study indicates that OSAHS patients have higher serum YKL-40 level, which may serve as a potential biomarker for OSAHS diagnosis and monitoring.

Plasm YKL-40 Levels Are Associated with Hypertension in Patients with Obstructive Sleep Apnea

Background

Obstructive sleep apnea (OSA) is a common disease. It can cause many serious complications. OSA may increase the risk of hypertension. However, the exact mechanism of OSA causing hypertension is not fully understood. YKL-40/chitinase-3-like protein-1 plays an important role in vascular injury, repair, and generation. We sought to explore the role of YKL-40 in endothelial dysfunction and hypertension in OSA patients.

Methods

All subjects were examined by polysomnography (PSG) and the expression of YKL-40 in the plasm of the subjects was measured by luminex. Carotid intima-media thickness (CIMT) was measured by B-mode ultrasound.

Results

According to the conditions of OSA and hypertension, we studied four groups of 157 subjects, including OSA group (OSA, N=77), OSA with hypertension group (OSA+HT, N=37), hypertension group (HT, N=20), and healthly group (Con, N=23). YKL-40 levels were significantly elevated in OSA, OSA+HT, and HT group compared to Con groups. We used the ROC to predict the sensitivity and specificity of YKL-40 in all OSA patients or all hyperpietic patients. For OSA patients, the AUC of YKL-40 is 0.807 (95% confidence interval 0.725–0.888; p<0.01). For hyperpietic patients, the AUC of YKL-40 is 0.656 (95% confidence interval 0.570–0.742, p=0.01). There was a significant correlation between the parameter of OSA and hypertension and YKL-40 (P<0.05) and a significant correlation between Max-CIMT and YKL-40 (P<0.05).

Conclusion

Elevated circulating levels of YKL-40 are associated with hypertension in OSA patients. The specificity of YKL-40 suggests that it could be a potential biomarker for OSA and hypertension.

Obesity modulates the association between sleep apnea treatment and CHI3L1 levels but not CHIT1 activity in moderate to severe OSA: an observational study

Purpose

The inflammatory markers chitinase-3-like protein 1 (CHI3L1) and chitotriosidase (CHIT1) have both been associated with cardiovascular complications. The aim of this preliminary observational study was to assess the roles and interaction of obstructive sleep apnea (OSA) severity and body mass index (BMI) with plasma CHI3L1 levels and CHIT1 activity in patients with moderate to severe OSA. The second aim was to assess the roles and interaction of positive airway pressure (PAP) treatment and BMI on the expression of the same proteins.

Methods

The study included 97 OSA patients with an apnea–hypopnea index (AHI) ≥ 15 and full usage of PAP treatment after 4 months. Plasma CHI3L1 levels and CHIT1 activity were measured before and after treatment.

Results

Multiple linear regression analysis demonstrated an independent association of BMI on CHI3L1 levels (p < 0.05) but not on CHIT1 activity. The OSA severity markers (AHI and oxygen desaturation index) did not independently or in interaction with BMI levels associate with CHI3L1 levels or with CHIT1 activity (p > 0.05). A two-way repeated measures ANOVA revealed a significant interaction between PAP treatment effect (before vs. after) and BMI groups (< 35 kg/m² vs. ≥ 35 kg/m²) on CHI3L1 levels (p = 0.03) but not on CHIT1 activity (p = 0.98).

Conclusions

Obesity independently associated with CHI3L1 levels. Association between OSA severity and CHI3L1 levels or CHIT1 activity (independent of or dependent on obesity level) could not be confirmed. However, decrease was observed in CHI3L1 levels after PAP treatment in severely obese OSA patients but not in those less obese.

Electronic supplementary material

The online version of this article (10.1007/s11325-018-1731-6) contains supplementary material, which is available to authorized users.

Association between obstructive sleep apnea and non-alcoholic fatty liver disease: a systematic review and meta-analysis

The relationship between obstructive sleep apnea (OSA) and non-alcoholic fatty liver disease (NAFLD) has been an issue of great concern. The primary purpose of this study was to determine the influence of OSA on the levels of liver enzymes including alanine transaminase (ALT) and aspartate transaminase (AST). The secondary purpose was to estimate the effect of OSA on the histological lesions of NAFLD, such as steatosis, lobular inflammation, ballooning degeneration, fibrosis, as well as NAFLD activity score (NAS). A systematic literature review using PubMed, Cochrane Library, Embase, and Ovid technologies from January 2007 to April 2017 was performed, and 9 studies (2272 participants) that met the selection criteria were evaluated. The present study demonstrated that OSA was related to ALT levels, but no significant correlation was found with AST levels. The subgroup analysis showed that the severity of OSA was associated with ALT levels, not with AST levels. The meta-regression analysis showed that age, sex, homeostasis model assessment, diabetes mellitus, body mass index, and waist circumference did not have a significant effect on the levels of ALT and AST. OSA was also found to be significantly correlated with steatosis, lobular inflammation, ballooning degeneration, and fibrosis, but was not correlated with NAS. OSA was independently related to the development and progression of NAFLD in terms of liver enzyme level and histological alterations. Future studies should investigate the possible relevant mechanisms, thereby guiding the exploration of potential therapeutic implications to prevent the progression of disease.

Course of SP-D, YKL-40, CCL18 and CA 15-3 in adult patients hospitalised with community-acquired pneumonia and their association with disease severity and aetiology: A post-hoc analysis

BACKGROUND AND AIM

SP-D, YKL-40, CCL18 and CA 15-3 are pulmonary markers that have been extensively investigated in different chronic pulmonary diseases. However, in acute pulmonary diseases, such as community-acquired pneumonia (CAP), little is known about the course of these markers and their relationship with the aetiological agent. The aim of this study was to investigate the course of these four markers in CAP and to study influence of disease severity, aetiology and antibiotic use prior to admission on their course.

METHODS

We included 291 adult patients hospitalised with CAP and 20 healthy controls. Measurements were performed in serum of day 0, 2, and 4, and at least 30 days after admission.

RESULTS

Our most important results were: 1) At all time-points, including 30 days after admission, YKL-40 and CCL18 levels were higher in CAP patients compared to healthy controls; and 2) Patients with CAP caused by an intracellular, atypical bacterium had lower YKL-40 and especially CCL18 levels on and during admission in comparison with other or unknown CAP aetiology.

CONCLUSIONS

Our findings suggest that these pulmonary markers could be useful to assess CAP severity and, especially YKL-40 and CCL18 by helping predict CAP caused by atypical pathogens.

YKL-40, CCL18 and SP-D predict mortality in patients hospitalized with community-acquired pneumonia

BACKGROUND AND OBJECTIVE

The aim of this study was to investigate the prognostic value of four biomarkers, YKL-40, chemokine (C-C motif) ligand 18 (CCL18), surfactant protein-D (SP-D) and CA 15-3, in patients admitted with community-acquired pneumonia (CAP). These markers have been studied extensively in chronic pulmonary disease, but in acute pulmonary disease their prognostic value is unknown.

METHODS

A total of 289 adult patients who were hospitalized with CAP and participated in a randomized controlled trial were enrolled. Biomarker levels were measured on the day of admission. Intensive care unit admission, 30-day, 1-year and long-term mortality (median follow-up of 5.4 years, interquartile range (IQR): 4.7-6.1) were recorded as outcomes.

RESULTS

Median YKL-40 and CCL18 levels were significantly higher and levels of SP-D were significantly lower in CAP patients compared to healthy controls. Significantly higher YKL-40, CCL18 and SP-D levels were found in patients classified in pneumonia severity index classes 4-5 and with a CURB-65 score ≥2 compared to patients with less severe pneumonia. Furthermore, these three markers were significant predictors for long-term mortality in multivariate analysis and compared with C-reactive protein and procalcitonin level on admission, area under the curves were higher for 30-day, 1-year and long-term mortality. CA 15-3 levels were less predictive.

CONCLUSION

YKL-40, CCL18 and SP-D levels were higher in patients with more severe pneumonia, possibly reflecting the extent of pulmonary inflammation. Of these, YKL-40 most significantly predicts mortality for CAP.

Investigation of the Levels of Serum Amyloid A, YKL-40, and Pentraxin-3 in Patients with Familial Mediterranean Fever

BACKGROUND

Familial Mediterranean Fever (FMF) is an autosomal recessive form of recurrent episodes of fever and an autoinflammatory disease characterized by inflammation of the serous membranes. The clinical diagnosis is supported by the laboratory findings. This study investigated the relationship of Serum Amyloid A (SAA), YKL-40, and Pentraxin-3 (PTX-3) with the FMF disease.

METHODS

About 50 patients with FMF were enrolled in this study. Patients were divided into three groups according to disease severity score (mild, moderate, and severe). Thirty-seven healthy individuals were included as the control group. Serum SAA, YKL-40, and PTX-3 concentrations were measured using an ELISA kit.

RESULTS

Serum SAA and YKL-40 levels of FMF patients were significantly higher than in the control (P < 0.001). PTX-3 levels were found to be higher in patients even though there was no significant difference (P = 0.113). Whereas the positive predictive value was 71.9% for cut-off point of SAA, the positive predictive value was 83.3% for cut-off point of YKL-40. Whereas a significant correlation was detected in SAA and PTX-3 with YKL-40 (respectively; P = 0.036, P < 0.001), there was no correlation between the PTX-3 with SAA (P = 0.219).

CONCLUSIONS

YKL-40 can be used together with SAA to support the diagnosis of FMF and to monitor the severity of the disease. In this study, YKL-40 levels were examined for the first time in FMF patients and further studies are necessary using larger patient samples.

OSAS-related inflammatory mechanisms of liver injury in nonalcoholic fatty liver disease

Obstructive sleep apnoea syndrome (OSAS) is a common sleep disorder, affecting over 4% of the general population, and is associated with metabolic syndrome and cardiovascular disease, independent of obesity and traditional risk factors. OSAS has been recently connected to nonalcoholic fatty liver disease (NAFLD), the most common chronic liver disease in the world, which can be found in 30% of the general adult population. Several studies suggest that the chronic intermittent hypoxia (CIH) of OSAS patients may per se trigger liver injury, inflammation, and fibrogenesis, promoting NAFLD development and the progression from steatosis to steatohepatitis, cirrhosis, and hepatocellular carcinoma. In NAFLD patients, liver disease may be caused by hypoxia both indirectly by promoting inflammation and insulin resistance and directly by enhancing proinflammatory cytokine production and metabolic dysregulation in liver cells. In this review, we focus on molecular mechanisms linking OSAS to NAFLD, including hypoxia inducible factor (HIF), nuclear factor kappa B (NF-κB), YKL-40, unfolded protein response, and hypoxic adipose tissue inflammation, which all could provide novel potential therapeutic approaches for the management of NAFLD patients with OSAS.

Inflammation in sleep apnea: an update

Obstructive sleep apnea (OSA) is a common disorder associated with cardiovascular disease (CVD). One theory to explain this relationship proposes that OSA can induce systemic inflammation, thereby inducing CVD. This theory is based on the premise that obesity is a pro-inflammatory state, and that physiological derangements during sleep in subjects with OSA further aggravate inflammation. In support of this theory, some clinical studies have shown elevated inflammatory biomarkers in OSA subjects, or improvement in these markers following treatment of OSA. However, the data are inconsistent and often confounded by the effects of comorbid obesity. Animal models of OSA have been developed, which involve exposure of rodents or cells to intermittent hypoxia, a hallmark feature of OSA. Several of these experiments demonstrate that intermittent hypoxia can stimulate inflammatory pathways and lead to cardiovascular or metabolic pathology. In this review, we review relationships between OSA and inflammation, with particular attention to studies published within the last year.

Diagnostic capability of biological markers in assessment of obstructive sleep apnea: a systematic review and meta-analysis

OBJECTIVE

The purpose of this systematic review is to evaluate the diagnostic value of biological markers (exhaled breath condensate, blood, salivary and urinary) in the diagnosis of OSA in comparison to the gold standard of nocturnal PSG.

METHODS

Studies that differentiated OSA from controls based on PSG results, without age restriction, were eligible for inclusion. The sample of selected studies could include studies in obese patients and with known cardiac disease. A detailed individual search strategy for each of the following bibliographic databases was developed: Cochrane, EMBASE, MEDLINE, PubMed, and LILACS. The references cited in these articles were also crosschecked and a partial grey literature search was undertaken using Google Scholar. The methodology of selected studies was evaluated using the 14-item Quality Assessment Tool for Diagnostic Accuracy Studies.

RESULTS

After a two-step selection process, nine articles were identified and subjected to qualitative and quantitative analyses. Among them, only one study conducted in children and one in adults found biomarkers that exhibit sufficiently satisfactory diagnostic accuracy that enables application as a diagnostic method for OSA.

CONCLUSION

Kallikrein-1, uromodulin, urocotin-3, and orosomucoid-1 when combined have enough accuracy to be an OSA diagnostic test in children. IL-6 and IL-10 plasma levels have potential to be good biomarkers in identifying or excluding the presence of OSA in adults.

Biomarkers associated with obstructive sleep apnea: A scoping review

The overall validity of biomarkers in the diagnosis of obstructive sleep apnea (OSA) remains unclear. We conducted a scoping review to provide assessments of biomarkers characteristics in the context of obstructive sleep apnea (OSA) and to identify gaps in the literature. A scoping review of studies in humans without age restriction that evaluated the potential diagnostic value of biological markers (blood, exhaled breath condensate, salivary, and urinary) in the OSA diagnosis was undertaken. Retained articles were those focused on the identification of biomarkers in subjects with OSA, the latter being confirmed with a full overnight or home-based polysomnography (PSG). Search strategies for six different databases were developed. The methodology of selected studies was classified using an adaptation of the evidence quality criteria from the American Academy of Pediatrics. Additionally the biomarkers were classified according to their potential clinical application. We identified 572 relevant studies, of which 117 met the inclusion criteria. Eighty-two studies were conducted in adults, 34 studies involved children, and one study had a sample composed of both adults and children. Most of the studies evaluated blood biomarkers. Potential diagnostic biomarkers were found in nine pediatric studies and in 58 adults studies. Only nine studies reported sensitivity and specificity, which varied substantially from 43% to 100%, and from 45% to 100%, respectively. Studies in adults have focused on the investigation of IL-6, TNF-α and hsCRP. There was no specific biomarker that was tested by a majority of authors in pediatric studies, and combinatorial urine biomarker approaches have shown preliminary promising results. In adults IL-6 and IL-10 seem to have a favorable potential to become a good biomarker to identify OSA.