GENETIC TESTING AND MOLECULAR BIOMARKERS Volume 19, Number 3, 2015 ª Mary Ann Liebert, Inc. Pp. 124–127 DOI: 10.1089/gtmb.2014.0274
Serum Endocan Levels Are Correlated with the Presence and Severity of Coronary Artery Disease in Patients with Hypertension Xiang-sheng Wang,1 Wen Yang,2 Tong Luo,1 Jian-ming Wang,3 and Yan-yan Jing 4
Background: Endothelial dysfunction is one of the most important early indicators of atherosclerosis in hypertension (HT) patients. Endocan has been reported to play a role in the pathophysiology of endothelial dysfunction. Objective: We sought to assess whether serum endocan levels are correlated with the presence and severity of coronary artery disease (CAD) in patients with HT. Methods: We measured endocan levels in 164 patients with HT and in 55 controls. The severity of CAD was assessed by the coronary atherosclerosis index scores. Results: Serum endocan levels were independently correlated with the presence and severity of CAD in HT patients. Conclusion: Endocan might function as a useful biomarker for monitoring the development and progression of CAD in HT patients.
Introduction
H
ypertension (HT) is one of the most important risk factors for coronary artery disease (CAD) (Yang and Yu, 2014). Accelerated atherosclerosis and increased risk of cardiovascular events are frequently reported in patients with HT. Thus, it is of great importance to assess the risk of CAD in patients with HT earlier. Noninvasive blood biomarkers have increasingly emerged as important alternatives to traditional methods for diagnosing and stratifying the risk of disease at its earliest stage. Endocan, previously named endothelial cell-specific molecule-1, is a soluble proteoglycan of 50 kDa, constituting a mature polypeptide of 165 amino acids and a single dermatan sulfate chain covalently linked to the serine residue at position 137 (Sarrazin et al., 2006). Endocan is synthesized and secreted by activated vascular endothelial cells (Ozaki et al., 2014). Previous studies have verified that endocan might play a key role in the pathophysiology of endothelial dysfunction by regulating major processes such as cell adhesion in inflammatory disorders (Sarrazin et al., 2006; Balta et al., 2013, 2014). It is well known that endothelial dysfunction is a key early event in atherogenesis and is integral to the onset of CAD. A recent study has demonstrated that serum endocan levels correlated positively with carotid maximum intimamedia thickness (cIMT) in essential HT patients (Balta et al., 2014). However, the relationship between serum endocan levels and the development and progression of
CAD has never been fully elucidated. Therefore, the present study aims to investigate the correlation of serum endocan levels with the presence and severity of CAD in patients with HT. Materials and Methods Study population
From March 2013 to March 2014, we recruited 164 consecutive HT patients who were highly suspected with CAD undergoing coronary angiography in Yuhuangding hospital. After coronary angiography, all the HT patients were classified into patients with and without CAD. Fifty-five age- and sex-matched volunteers undergoing routine physical examination in Yuhuangding hospital were recruited as controls during the same period. HT was defined as systolic blood pressure (SBP) ‡ 140 mmHg, diastolic blood pressure (DBP) ‡ 90 mmHg, or use of antihypertensive drugs. Angiographic CAD was defined as the presence of ‡ 50% luminal stenosis in at least one major coronary artery. Those who had acute coronary syndromes, active inflammatory disease, autoimmune disorders, previously documented CAD, suspected myocarditis or pericarditis, severe heart failure, advanced renal and hepatic disease, malignant disease, and diabetes were excluded. Informed consent was obtained from all participants. This study was approved by the ethics committee of Yuhuangding hospital.
Departments of 1Internal Medicine and 3Cardiovascular Medicine, Chinese Medicine Hospital of Jining, Jining, People’s Republic of China. Departments of 2Nephrology and 4Cardiology, Qingdao University Affiliated Yuhuangding Hospital, Yantai, People’s Republic of China.
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ENDOCAN AND CORONARY ARTERY DISEASE Coronary angiography analysis
Conventional invasive coronary angiography was performed according to standard protocols by interventional cardiologists blinded to the study protocol. Severity of coronary stenosis in patients was estimated by the coronary atherosclerosis index (CAI) scores (Tatami et al., 1981). The Gensini system scores the narrowing of the coronary artery. The CAI was defined as the sum of the scores by assigning points to each lesion as follows: a no significant stenosis of the luminal diameter, 0; stenosis of less than 25%, 1; 25–49% stenosis, 2; 50–74%, 3; and 75–100%, 4. Laboratory tests
Conventional laboratory parameters, such as fasting blood glucose (FBG) and fasting plasma lipid (i.e., total cholesterol [TC], triglycerides [TG], high-density lipoprotein cholesterol [HDL-c], and low-density lipoprotein cholesterol [LDL-c]) levels, were measured using standard laboratory procedures at the Department of Clinical Chemistry of Yuhuangding hospital. Serum endocan levels were determined using a commercially available sandwich enzyme-linked immunosorbent assay (ELISA) kit with high sensitivity specificity for detection of human endocan (Aviscera Bioscience). All the serum samples were routinely analyzed by ELISA in duplicate, and the results were averaged. Preliminary data obtained in our laboratory showed that the intra-assay and interassay coefficients of variation for endocan were both below 5%. The ELISA was conducted in the Yuhuangding Hospital using an Anthos2010 automatic microplate reader (Anthos Labtec Instruments GmbH).
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variables with skewed distribution are expressed as the median value (interquartile range), and categorical variables as frequencies or percentages. Tests of data normality were performed using the Kolmogorov–Smirnov test. Differences between the two groups were analyzed using the unpaired ttest, Mann–Whitney U test, or Chi-square test as indicated. Differences among groups were analyzed by one-way analysis of variance, the Kruskal–Wallis analysis, or Chi-square test when appropriate. Simple logistic analysis was employed and the variables with p < 0.20 were then entered into a backward stepwise multivariate logistic regression model to assess the independent predictors for CAD. Spearman’s/ Pearson correlation analysis was employed to determine the correlation between variables and CAI scores. Multivariate linear regression analysis was performed to assess the independent predictors of log (CAI scores). Probability values (two-tailed) were considered significant at p < 0.05. Statistical analyses were performed with the SPSS 17.0 for Windows version (SPSS, Inc.). Results Baseline clinical characteristics
The baseline clinical characteristics of the study groups are shown in Table 1. Compared with controls, HT patients had significantly higher body–mass index, SBP, DBP, and TG levels. Besides, HT patients had significantly lower HDL-c levels. In HT patients, patients with CAD had significantly higher TG levels and lower HDL-c levels than those without CAD.
Statistical analyses
Serum endocan levels
Results of normally distributed continuous variables are expressed as the mean value – SD, those for continuous
HT patients had significantly higher serum endocan levels compared with controls (1.39 [range 0.83–1.83] ng/mL vs.
Table 1. Baseline Clinical Characteristics and Serum Endocan Levels HT patients Variables Age (years) Male, n (%) Smoking, n (%) BMI (Kg/mm2) SBP (mm/Hg) DBP (mmHg) FBG (mM) TC (mM) TG (mM) LDL-c (mM) HDL-c (mM) Cardiovascular medication Statins, n (%) ACEI/ARB, n (%) CCB, n (%) b-blocker, n (%) Endocan (ng/mL)
Controls (n = 55)
Without CAD (n = 92)
With CAD (n = 72)
61.24 – 9.21 32, (58.19%) 22, (40.00%) 24.43 (23.51–25.52)a 125.42 – 17.96a 78.18 – 9.85a 5.55 – 1.16 4.54 – 1.34 1.41 (1.00–2.22)a 2.55 – 0.87 1.27 – 0.24a
60.63 – 7.98 53, (57.61%) 40, (43.48%) 25.58 (24.47–26.02) 136.95 – 15.13 91.86 – 10.74 5.70 – 0.71 4.74 – 0.99 1.80 (1.41–2.44) 2.74 – 0.84 1.18 – 0.23
62.25 – 8.53 41, (56.94%) 34, (47.22%) 24.91 (24.04–27.08) 137.75 – 19.42 90.76 – 13.54 5.85 – 0.59 4.89 – 1.11 1.56 (1.18–2.19)b 2.87 – 0.90 1.07 – 0.20b
0, (0.00%)a 0, (0.00%)a 0, (0.00%)a 0, (0.00%)a 0.73 (0.58–0.92)a
16, (17.39%) 25, (27.17%) 27, (29.35%) 18, (19.57%) 1.18 (0.79–1.61)
15, (20.83%) 21, (29.17%) 23, (31.94%) 16, (22.22%) 1.47 (1.11–2.42)b
All values are mean – SD, median value (interquartile range), or n (%). a p < 0.05 compared with HT patients. b p < 0.05 compared with patients without CAD. HT, hypertension; CAD, coronary artery disease, BMI, body–mass index; SBP, systolic blood pressure; DBP, diastolic blood pressure; FBG, fasting glucose; TC, total cholesterol; TG, triglycerides; LDL-c, low-density lipoprotein cholesterol; HDL-c, high-density lipoprotein cholesterol; ACEI, angiotensin-converting enzyme inhibitor; ARB, angiotensin receptor blocker; CCB, calcium channel blocker.
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Table 2. Logistic Regression Analysis for the Presence of CAD in HT Patients Simple regression Variables Age (per year) Male (no/yes) Smoking (no/yes) BMI (per Kg/mm2) SBP (per mm/Hg) DBP (per mmHg) FBG (per mM) TC (per mM) TG (per mM) LDL-c (per mM) HDL-c (per mM) Statins (no/yes) ACEI/ARB (no/yes) CCB (no/yes) b-blocker (no/yes) Endocan (per ng/mL)
OR (95% CI) 1.02 0.97 0.86 0.96 1.00 0.99 1.42 1.16 0.64 1.19 0.11 1.25 0.91 0.89 0.85 2.15
(0.99–1.06) (0.52–1.82) (0.46–1.60) (0.85–1.08) (0.99–1.02) (0.97–1.02) (0.88–2.28) (0.86–1.56) (0.43–0.97) (0.83–1.70) (0.03–0.48) (0.57–2.74) (0.46–1.80) (0.45–1.73) (0.40–1.82) (1.39–3.34)
Multiple regression p-Value 0.21 0.93 0.63 0.47 0.76 0.56 0.15 0.34 0.04 0.35 < 0.01 0.58 0.78 0.72 0.68 < 0.01
OR (95% CI)
p-Value
1.41 (0.85–2.33)
0.18
0.68 (0.44–1.05)
0.08
0.11 (0.02–0.55)
< 0.01
2.05 (1.30–3.25)
< 0.01
OR, odds ratio; CI, confidence interval.
0.73 [range 0.58–0.92] ng/mL, p < 0.01). In HT patients, those with CAD had significantly higher serum endocan levels compared with those without CAD (1.47 [range 1.11–2.42] ng/ mL vs. 1.18 [range 0.79–1.61] ng/mL, p < 0.01; Table 1). Logistic regression analysis for the presence of CAD in HT patients
As shown in Table 2, simple logistic regression analysis demonstrated that FBG, TG, HDL-c, and endocan levels showed a trend ( p < 0.20) toward an association with the presence of CAD in HT patients. Multivariate logistic regression, including the variables mentioned above, revealed that serum endocan levels were independently associated with the presence of CAD in HT patients [odds ratio (OR) 2.05, 95% confidence interval (CI) 1.30–3.25, p < 0.01] (Table 2).
endocan messenger RNA and a sustained release of the molecule by the endothelium (Lassalle et al., 1996). Previous studies have demonstrated that patients with essential HT have high levels of inflammatory cytokines such as IL-1b and TNF-a (Dalekos et al., 2000; Fang et al., 2013). We therefore postulated that endocan might be also overexpressed in HT patients. In the present study, we found increased serum endocan levels in patients with HT compared with controls. This result is in accordance with a previous study (Balta et al., 2014) and confirms the association between endocan and HT. Endocan is a human endothelial cell-specific molecule. Experimental evidence indicates that endocan is a key player in the regulation of endothelial dysfunction through promoting
Correlation of serum endocan levels with the CAI
In HT patients with CAD, Spearman’s correlation revealed that serum endocan levels were significantly correlated with CAI scores (r = 0.35, p < 0.01; Fig. 1). Multivariate linear regression analysis showed that endocan was the independent contribution to log (CAI) after controlling for potential confounders (b = 0.44, t = 3.57, p < 0.01). Discussion
In this study, we demonstrated that HT patients with CAD had significantly higher serum endocan levels than those without CAD. Serum endocan levels were independently correlated with the presence and severity of CAD in HT patients. To the best of our knowledge, the present study is the first addressing the relationship between endocan levels and CAD in HT patients. Endocan is expressed by endothelial cells in the lung and kidney (Bechard et al., 2000) and can be detected in human blood (Lassalle et al., 1996; Scherpereel et al., 2006). In vitro, inflammatory cytokines such as interleukin (IL)-1b and tumor necrosis factor (TNF)-a can induce an upregulation of
FIG. 1. Correlations between serum endocan levels and the severity of coronary artery disease evaluated by the CAI score. CAI, coronary atherosclerosis index.
ENDOCAN AND CORONARY ARTERY DISEASE
endothelium-specific inflammatory disorders (Bechard et al., 2000; Balta et al., 2013). Therefore, endocan may be considered as a surrogate endothelial dysfunction marker with also a role in endothelium-dependent pathological disorders. It is well known that endothelial dysfunction is one of the most important early indicators of atherosclerosis in HT patients. Therefore, there might be a missing cross talk between endocan and CAD resulting from endothelial dysfunction. We demonstrated in the present study that serum endocan levels were significantly higher in CAD patients than those in nonCAD patients, and the increased endocan level was the independent risk factor for predicting the presence of CAD in HT patients. These results concurred with those of earlier studies linking endocan to CAD and suggested that endocan might be a potential biomarker for providing valuable information about the development of CAD in HT patients. One of the important findings of the present study was that serum endocan levels were independently correlated with CAI scores in CAD patients. CAI is a valid and reliable scoring system that assesses the extent and severity of CAD (Zhao et al., 2013). This result is in accordance with a previous study by Balta et al. (2014), which revealed that serum endocan levels correlated positively with cIMT in HT patients. cIMT is a marker of subclinical atherosclerosis progression (Balci et al., 2009). All these results suggested that high serum endocan levels might be also correlated with the progression of CAD in HT patients. However, the association between serum endocan levels and CAI scores was moderate and its clinical significance is yet to be further investigated. The potential limitations of the present study should be noted. First, this study has been designed as a crosssectional study with a relatively small sample size. Such a study cannot establish causality. It shows some association and is hypothesis generating. Multicenter prospective longitudinal studies with a larger sample size may be needed for more comprehensive investigation. Second, we did not monitor other proinflammatory cytokines (e.g., C-reactive protein) and assess the association between these cytokines and endocan in this study. Such investigations may reveal more valuable information on the possible pathogenic role of endocan in CAD. In conclusion, we revealed that serum endocan levels were independently correlated with the presence and severity of CAD in patients with HT. These findings indicated that endocan might function as a useful biomarker for monitoring the development and progression of CAD in HT patients. The efficacy of therapies to target endocan to delay the degenerative process of CAD warrants further investigations. Acknowledgment
The authors thank the catheterization laboratory staff of Yuhuangding Hospital for their enthusiasm in supporting the study. This study was supported by the Project of Science and Technology Development Plan in Shandong Province (2012YD18009).
127 Author Disclosure Statement
No competing financial interests exist. References
Balci DD, Balci A, Karazincir S, et al. (2009) Increased carotid artery intima-media thickness and impaired endothelial function in psoriasis. J Eur Acad Dermatol Venereol 23:1–6. Balta I, Balta S, Demirkol S, et al. (2013) Elevated serum levels of endocan in patients with psoriasis vulgaris: correlations with cardiovascular risk and activity of disease. Br J Dermatol 169:1066–1070. Balta S, Mikhailidis DP, Demirkol S, et al. (2014) Endocan—a novel inflammatory indicator in newly diagnosed patients with hypertension: a pilot study. Angiology 65:773–777. Bechard D, Meignin V, Scherpereel A, et al. (2000) Characterization of the secreted form of endothelial-cell-specific molecule 1 by specific monoclonal antibodies. J Vasc Res 37:417–425. Dalekos GN, Elisaf MS, Papagalanis N, et al. (2000) Elevated interleukin-1 beta in the circulation of patients with essential hypertension before any drug therapy: a pilot study. Eur J Clin Invest 26:936–939. Fang C, Lei J, Zhou SX, et al. (2013) Association of higher resistin levels with inflammatory activation and endothelial dysfunction in patients with essential hypertension. Chin Med J (Engl) 126:646–649. Lassalle P, Molet S, Janin A, et al. (1996) ESM-1 is a novel human endothelial cell-specific molecule expressed in lung and regulated by cytokines. J Biol Chem 271:20458–20464. Ozaki K, Toshikuni N, George J, et al. (2014) Serum endocan as a novel prognostic biomarker in patients with hepatocellular carcinoma. J Cancer 5:221–230. Sarrazin S, Adam E, Lyon M, et al. (2006) Endocan or endothelial cell specific molecule-1 (ESM-1): a potential novel endothelial cell marker and a new target for cancer therapy. Biochim Biophys Acta 1765:25–37. Scherpereel A, Depontieu F, Grigoriu B, et al. (2006) Endocan, a new endothelial marker in human sepsis. Crit Care Med 34:532–537. Tatami R, Mabuchi H, Ueda K, et al. (1981) Intermediatedensity lipoprotein and cholesterol-rich very low density lipoprotein in angiographically determined coronary artery disease. Circulation 64:1174–1184. Yang R, Yu J (2014) Evaluation of the associations between vascular endothelial function and coronary artery stenosis in patients with elevated blood pressure during coronary angiography. Heart Surg Forum 17:E150–E153. Zhao ZW, Lin CG, Wu LZ, et al. (2013) Serum fetuin-A levels are associated with the presence and severity of coronary artery disease in patients with type 2 diabetes. Biomarkers 18: 160–164.
Address correspondence to: Yan-yan Jing, MD Department of Cardiology Qingdao University Affiliated Yuhuangding Hospital No. 20 Yuhuangding East Road Yantai 264000 People’s Republic of China E-mail: [email protected]
Serum Endocan Levels Are Correlated with the Presence and Severity of Coronary Artery Disease in Patients with Hypertension Xiang-sheng Wang,1 Wen Yang,2 Tong Luo,1 Jian-ming Wang,3 and Yan-yan Jing 4
Background: Endothelial dysfunction is one of the most important early indicators of atherosclerosis in hypertension (HT) patients. Endocan has been reported to play a role in the pathophysiology of endothelial dysfunction. Objective: We sought to assess whether serum endocan levels are correlated with the presence and severity of coronary artery disease (CAD) in patients with HT. Methods: We measured endocan levels in 164 patients with HT and in 55 controls. The severity of CAD was assessed by the coronary atherosclerosis index scores. Results: Serum endocan levels were independently correlated with the presence and severity of CAD in HT patients. Conclusion: Endocan might function as a useful biomarker for monitoring the development and progression of CAD in HT patients.
Introduction
H
ypertension (HT) is one of the most important risk factors for coronary artery disease (CAD) (Yang and Yu, 2014). Accelerated atherosclerosis and increased risk of cardiovascular events are frequently reported in patients with HT. Thus, it is of great importance to assess the risk of CAD in patients with HT earlier. Noninvasive blood biomarkers have increasingly emerged as important alternatives to traditional methods for diagnosing and stratifying the risk of disease at its earliest stage. Endocan, previously named endothelial cell-specific molecule-1, is a soluble proteoglycan of 50 kDa, constituting a mature polypeptide of 165 amino acids and a single dermatan sulfate chain covalently linked to the serine residue at position 137 (Sarrazin et al., 2006). Endocan is synthesized and secreted by activated vascular endothelial cells (Ozaki et al., 2014). Previous studies have verified that endocan might play a key role in the pathophysiology of endothelial dysfunction by regulating major processes such as cell adhesion in inflammatory disorders (Sarrazin et al., 2006; Balta et al., 2013, 2014). It is well known that endothelial dysfunction is a key early event in atherogenesis and is integral to the onset of CAD. A recent study has demonstrated that serum endocan levels correlated positively with carotid maximum intimamedia thickness (cIMT) in essential HT patients (Balta et al., 2014). However, the relationship between serum endocan levels and the development and progression of
CAD has never been fully elucidated. Therefore, the present study aims to investigate the correlation of serum endocan levels with the presence and severity of CAD in patients with HT. Materials and Methods Study population
From March 2013 to March 2014, we recruited 164 consecutive HT patients who were highly suspected with CAD undergoing coronary angiography in Yuhuangding hospital. After coronary angiography, all the HT patients were classified into patients with and without CAD. Fifty-five age- and sex-matched volunteers undergoing routine physical examination in Yuhuangding hospital were recruited as controls during the same period. HT was defined as systolic blood pressure (SBP) ‡ 140 mmHg, diastolic blood pressure (DBP) ‡ 90 mmHg, or use of antihypertensive drugs. Angiographic CAD was defined as the presence of ‡ 50% luminal stenosis in at least one major coronary artery. Those who had acute coronary syndromes, active inflammatory disease, autoimmune disorders, previously documented CAD, suspected myocarditis or pericarditis, severe heart failure, advanced renal and hepatic disease, malignant disease, and diabetes were excluded. Informed consent was obtained from all participants. This study was approved by the ethics committee of Yuhuangding hospital.
Departments of 1Internal Medicine and 3Cardiovascular Medicine, Chinese Medicine Hospital of Jining, Jining, People’s Republic of China. Departments of 2Nephrology and 4Cardiology, Qingdao University Affiliated Yuhuangding Hospital, Yantai, People’s Republic of China.
124
ENDOCAN AND CORONARY ARTERY DISEASE Coronary angiography analysis
Conventional invasive coronary angiography was performed according to standard protocols by interventional cardiologists blinded to the study protocol. Severity of coronary stenosis in patients was estimated by the coronary atherosclerosis index (CAI) scores (Tatami et al., 1981). The Gensini system scores the narrowing of the coronary artery. The CAI was defined as the sum of the scores by assigning points to each lesion as follows: a no significant stenosis of the luminal diameter, 0; stenosis of less than 25%, 1; 25–49% stenosis, 2; 50–74%, 3; and 75–100%, 4. Laboratory tests
Conventional laboratory parameters, such as fasting blood glucose (FBG) and fasting plasma lipid (i.e., total cholesterol [TC], triglycerides [TG], high-density lipoprotein cholesterol [HDL-c], and low-density lipoprotein cholesterol [LDL-c]) levels, were measured using standard laboratory procedures at the Department of Clinical Chemistry of Yuhuangding hospital. Serum endocan levels were determined using a commercially available sandwich enzyme-linked immunosorbent assay (ELISA) kit with high sensitivity specificity for detection of human endocan (Aviscera Bioscience). All the serum samples were routinely analyzed by ELISA in duplicate, and the results were averaged. Preliminary data obtained in our laboratory showed that the intra-assay and interassay coefficients of variation for endocan were both below 5%. The ELISA was conducted in the Yuhuangding Hospital using an Anthos2010 automatic microplate reader (Anthos Labtec Instruments GmbH).
125
variables with skewed distribution are expressed as the median value (interquartile range), and categorical variables as frequencies or percentages. Tests of data normality were performed using the Kolmogorov–Smirnov test. Differences between the two groups were analyzed using the unpaired ttest, Mann–Whitney U test, or Chi-square test as indicated. Differences among groups were analyzed by one-way analysis of variance, the Kruskal–Wallis analysis, or Chi-square test when appropriate. Simple logistic analysis was employed and the variables with p < 0.20 were then entered into a backward stepwise multivariate logistic regression model to assess the independent predictors for CAD. Spearman’s/ Pearson correlation analysis was employed to determine the correlation between variables and CAI scores. Multivariate linear regression analysis was performed to assess the independent predictors of log (CAI scores). Probability values (two-tailed) were considered significant at p < 0.05. Statistical analyses were performed with the SPSS 17.0 for Windows version (SPSS, Inc.). Results Baseline clinical characteristics
The baseline clinical characteristics of the study groups are shown in Table 1. Compared with controls, HT patients had significantly higher body–mass index, SBP, DBP, and TG levels. Besides, HT patients had significantly lower HDL-c levels. In HT patients, patients with CAD had significantly higher TG levels and lower HDL-c levels than those without CAD.
Statistical analyses
Serum endocan levels
Results of normally distributed continuous variables are expressed as the mean value – SD, those for continuous
HT patients had significantly higher serum endocan levels compared with controls (1.39 [range 0.83–1.83] ng/mL vs.
Table 1. Baseline Clinical Characteristics and Serum Endocan Levels HT patients Variables Age (years) Male, n (%) Smoking, n (%) BMI (Kg/mm2) SBP (mm/Hg) DBP (mmHg) FBG (mM) TC (mM) TG (mM) LDL-c (mM) HDL-c (mM) Cardiovascular medication Statins, n (%) ACEI/ARB, n (%) CCB, n (%) b-blocker, n (%) Endocan (ng/mL)
Controls (n = 55)
Without CAD (n = 92)
With CAD (n = 72)
61.24 – 9.21 32, (58.19%) 22, (40.00%) 24.43 (23.51–25.52)a 125.42 – 17.96a 78.18 – 9.85a 5.55 – 1.16 4.54 – 1.34 1.41 (1.00–2.22)a 2.55 – 0.87 1.27 – 0.24a
60.63 – 7.98 53, (57.61%) 40, (43.48%) 25.58 (24.47–26.02) 136.95 – 15.13 91.86 – 10.74 5.70 – 0.71 4.74 – 0.99 1.80 (1.41–2.44) 2.74 – 0.84 1.18 – 0.23
62.25 – 8.53 41, (56.94%) 34, (47.22%) 24.91 (24.04–27.08) 137.75 – 19.42 90.76 – 13.54 5.85 – 0.59 4.89 – 1.11 1.56 (1.18–2.19)b 2.87 – 0.90 1.07 – 0.20b
0, (0.00%)a 0, (0.00%)a 0, (0.00%)a 0, (0.00%)a 0.73 (0.58–0.92)a
16, (17.39%) 25, (27.17%) 27, (29.35%) 18, (19.57%) 1.18 (0.79–1.61)
15, (20.83%) 21, (29.17%) 23, (31.94%) 16, (22.22%) 1.47 (1.11–2.42)b
All values are mean – SD, median value (interquartile range), or n (%). a p < 0.05 compared with HT patients. b p < 0.05 compared with patients without CAD. HT, hypertension; CAD, coronary artery disease, BMI, body–mass index; SBP, systolic blood pressure; DBP, diastolic blood pressure; FBG, fasting glucose; TC, total cholesterol; TG, triglycerides; LDL-c, low-density lipoprotein cholesterol; HDL-c, high-density lipoprotein cholesterol; ACEI, angiotensin-converting enzyme inhibitor; ARB, angiotensin receptor blocker; CCB, calcium channel blocker.
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Table 2. Logistic Regression Analysis for the Presence of CAD in HT Patients Simple regression Variables Age (per year) Male (no/yes) Smoking (no/yes) BMI (per Kg/mm2) SBP (per mm/Hg) DBP (per mmHg) FBG (per mM) TC (per mM) TG (per mM) LDL-c (per mM) HDL-c (per mM) Statins (no/yes) ACEI/ARB (no/yes) CCB (no/yes) b-blocker (no/yes) Endocan (per ng/mL)
OR (95% CI) 1.02 0.97 0.86 0.96 1.00 0.99 1.42 1.16 0.64 1.19 0.11 1.25 0.91 0.89 0.85 2.15
(0.99–1.06) (0.52–1.82) (0.46–1.60) (0.85–1.08) (0.99–1.02) (0.97–1.02) (0.88–2.28) (0.86–1.56) (0.43–0.97) (0.83–1.70) (0.03–0.48) (0.57–2.74) (0.46–1.80) (0.45–1.73) (0.40–1.82) (1.39–3.34)
Multiple regression p-Value 0.21 0.93 0.63 0.47 0.76 0.56 0.15 0.34 0.04 0.35 < 0.01 0.58 0.78 0.72 0.68 < 0.01
OR (95% CI)
p-Value
1.41 (0.85–2.33)
0.18
0.68 (0.44–1.05)
0.08
0.11 (0.02–0.55)
< 0.01
2.05 (1.30–3.25)
< 0.01
OR, odds ratio; CI, confidence interval.
0.73 [range 0.58–0.92] ng/mL, p < 0.01). In HT patients, those with CAD had significantly higher serum endocan levels compared with those without CAD (1.47 [range 1.11–2.42] ng/ mL vs. 1.18 [range 0.79–1.61] ng/mL, p < 0.01; Table 1). Logistic regression analysis for the presence of CAD in HT patients
As shown in Table 2, simple logistic regression analysis demonstrated that FBG, TG, HDL-c, and endocan levels showed a trend ( p < 0.20) toward an association with the presence of CAD in HT patients. Multivariate logistic regression, including the variables mentioned above, revealed that serum endocan levels were independently associated with the presence of CAD in HT patients [odds ratio (OR) 2.05, 95% confidence interval (CI) 1.30–3.25, p < 0.01] (Table 2).
endocan messenger RNA and a sustained release of the molecule by the endothelium (Lassalle et al., 1996). Previous studies have demonstrated that patients with essential HT have high levels of inflammatory cytokines such as IL-1b and TNF-a (Dalekos et al., 2000; Fang et al., 2013). We therefore postulated that endocan might be also overexpressed in HT patients. In the present study, we found increased serum endocan levels in patients with HT compared with controls. This result is in accordance with a previous study (Balta et al., 2014) and confirms the association between endocan and HT. Endocan is a human endothelial cell-specific molecule. Experimental evidence indicates that endocan is a key player in the regulation of endothelial dysfunction through promoting
Correlation of serum endocan levels with the CAI
In HT patients with CAD, Spearman’s correlation revealed that serum endocan levels were significantly correlated with CAI scores (r = 0.35, p < 0.01; Fig. 1). Multivariate linear regression analysis showed that endocan was the independent contribution to log (CAI) after controlling for potential confounders (b = 0.44, t = 3.57, p < 0.01). Discussion
In this study, we demonstrated that HT patients with CAD had significantly higher serum endocan levels than those without CAD. Serum endocan levels were independently correlated with the presence and severity of CAD in HT patients. To the best of our knowledge, the present study is the first addressing the relationship between endocan levels and CAD in HT patients. Endocan is expressed by endothelial cells in the lung and kidney (Bechard et al., 2000) and can be detected in human blood (Lassalle et al., 1996; Scherpereel et al., 2006). In vitro, inflammatory cytokines such as interleukin (IL)-1b and tumor necrosis factor (TNF)-a can induce an upregulation of
FIG. 1. Correlations between serum endocan levels and the severity of coronary artery disease evaluated by the CAI score. CAI, coronary atherosclerosis index.
ENDOCAN AND CORONARY ARTERY DISEASE
endothelium-specific inflammatory disorders (Bechard et al., 2000; Balta et al., 2013). Therefore, endocan may be considered as a surrogate endothelial dysfunction marker with also a role in endothelium-dependent pathological disorders. It is well known that endothelial dysfunction is one of the most important early indicators of atherosclerosis in HT patients. Therefore, there might be a missing cross talk between endocan and CAD resulting from endothelial dysfunction. We demonstrated in the present study that serum endocan levels were significantly higher in CAD patients than those in nonCAD patients, and the increased endocan level was the independent risk factor for predicting the presence of CAD in HT patients. These results concurred with those of earlier studies linking endocan to CAD and suggested that endocan might be a potential biomarker for providing valuable information about the development of CAD in HT patients. One of the important findings of the present study was that serum endocan levels were independently correlated with CAI scores in CAD patients. CAI is a valid and reliable scoring system that assesses the extent and severity of CAD (Zhao et al., 2013). This result is in accordance with a previous study by Balta et al. (2014), which revealed that serum endocan levels correlated positively with cIMT in HT patients. cIMT is a marker of subclinical atherosclerosis progression (Balci et al., 2009). All these results suggested that high serum endocan levels might be also correlated with the progression of CAD in HT patients. However, the association between serum endocan levels and CAI scores was moderate and its clinical significance is yet to be further investigated. The potential limitations of the present study should be noted. First, this study has been designed as a crosssectional study with a relatively small sample size. Such a study cannot establish causality. It shows some association and is hypothesis generating. Multicenter prospective longitudinal studies with a larger sample size may be needed for more comprehensive investigation. Second, we did not monitor other proinflammatory cytokines (e.g., C-reactive protein) and assess the association between these cytokines and endocan in this study. Such investigations may reveal more valuable information on the possible pathogenic role of endocan in CAD. In conclusion, we revealed that serum endocan levels were independently correlated with the presence and severity of CAD in patients with HT. These findings indicated that endocan might function as a useful biomarker for monitoring the development and progression of CAD in HT patients. The efficacy of therapies to target endocan to delay the degenerative process of CAD warrants further investigations. Acknowledgment
The authors thank the catheterization laboratory staff of Yuhuangding Hospital for their enthusiasm in supporting the study. This study was supported by the Project of Science and Technology Development Plan in Shandong Province (2012YD18009).
127 Author Disclosure Statement
No competing financial interests exist. References
Balci DD, Balci A, Karazincir S, et al. (2009) Increased carotid artery intima-media thickness and impaired endothelial function in psoriasis. J Eur Acad Dermatol Venereol 23:1–6. Balta I, Balta S, Demirkol S, et al. (2013) Elevated serum levels of endocan in patients with psoriasis vulgaris: correlations with cardiovascular risk and activity of disease. Br J Dermatol 169:1066–1070. Balta S, Mikhailidis DP, Demirkol S, et al. (2014) Endocan—a novel inflammatory indicator in newly diagnosed patients with hypertension: a pilot study. Angiology 65:773–777. Bechard D, Meignin V, Scherpereel A, et al. (2000) Characterization of the secreted form of endothelial-cell-specific molecule 1 by specific monoclonal antibodies. J Vasc Res 37:417–425. Dalekos GN, Elisaf MS, Papagalanis N, et al. (2000) Elevated interleukin-1 beta in the circulation of patients with essential hypertension before any drug therapy: a pilot study. Eur J Clin Invest 26:936–939. Fang C, Lei J, Zhou SX, et al. (2013) Association of higher resistin levels with inflammatory activation and endothelial dysfunction in patients with essential hypertension. Chin Med J (Engl) 126:646–649. Lassalle P, Molet S, Janin A, et al. (1996) ESM-1 is a novel human endothelial cell-specific molecule expressed in lung and regulated by cytokines. J Biol Chem 271:20458–20464. Ozaki K, Toshikuni N, George J, et al. (2014) Serum endocan as a novel prognostic biomarker in patients with hepatocellular carcinoma. J Cancer 5:221–230. Sarrazin S, Adam E, Lyon M, et al. (2006) Endocan or endothelial cell specific molecule-1 (ESM-1): a potential novel endothelial cell marker and a new target for cancer therapy. Biochim Biophys Acta 1765:25–37. Scherpereel A, Depontieu F, Grigoriu B, et al. (2006) Endocan, a new endothelial marker in human sepsis. Crit Care Med 34:532–537. Tatami R, Mabuchi H, Ueda K, et al. (1981) Intermediatedensity lipoprotein and cholesterol-rich very low density lipoprotein in angiographically determined coronary artery disease. Circulation 64:1174–1184. Yang R, Yu J (2014) Evaluation of the associations between vascular endothelial function and coronary artery stenosis in patients with elevated blood pressure during coronary angiography. Heart Surg Forum 17:E150–E153. Zhao ZW, Lin CG, Wu LZ, et al. (2013) Serum fetuin-A levels are associated with the presence and severity of coronary artery disease in patients with type 2 diabetes. Biomarkers 18: 160–164.
Address correspondence to: Yan-yan Jing, MD Department of Cardiology Qingdao University Affiliated Yuhuangding Hospital No. 20 Yuhuangding East Road Yantai 264000 People’s Republic of China E-mail: [email protected]
