Endocan Measurement for Active Behcet Disease.
Endocan is a dermatan sulphate proteoglycan molecule. It is an endothelial marker expressed by endothelial cells. (11) It has been suggested that endocan plays a significant role in organ-specific inflammation and it is a marker showing endothelial dysfunction. It leads to adhesion, migration of endothelial cells, and angiogenesis in numerous inflammatory disorders. (12-14) Endocan expression in vascular endothelium is regulated by various cytokines and growth factors. Additionally, it has been shown that there is an association between endocan level and vascular endothelial growth factor (VEGF) messenger ribonucleic acid in many studies. (15) It has been stated that endocan release is regulated by cytokines and growth factors such as VEGF in numerous studies. Moreover, in these studies, VEGF was found to induce endocan release through stimulation of endothelial migration and angiogenesis, which are induced by VEGF-A. (16,17) In a recently conducted study, endocan was shown to play a key role in regulation of cellular adhesion, inflammatory diseases, and growth and progression of tumors. (16,17) Additionally, endocan expression in endothelial cells is upregulated as a response to tumor necrosis factor-alpha (TNF-[alpha]). (18,19) TNF-[alpha] is among the cytokines which were investigated in most detail in BD. There are numerous multicentered and multi-national studies conducted with TNF-[alpha]. (20) There are also several studies in BD, verifying the therapeutic efficacy of antiTNF-[alpha] agents, especially in uveitis. (19)
In this study, we aimed to investigate the relationships between serum endocan, VEGF, and TNF-[alpha] levels in active BD.
PATIENTS AND METHODS
All participants who were admitted to Ataturk University Physical Therapy and Rehabilitation and Eye Clinic between November 2014 and February 2015 were included in the study. A total of 40 patients (24 males, 16 females; mean age 37.6 [+ or -] 8.7 years; range 20 to 50 years) whose disease was at active state (clinically active uveitis and/or arthritis findings) were included in the study together with 40 age and sex-matched healthy participants (22 males, 18 females; mean age 38.8 [+ or -] 7.9 years; range 21 to 52 years) as the control group. The diagnosis of BD was made according to the criteria of International Study group for BD. (20) The exclusion criteria were presence of obesity (body mass index >30 kg/[m.sup.2]), metabolic syndrome, diabetes mellitus, thyroid dysfunction, alcohol consumption, smoking, hyperlipidemia, hypertension, heart failure, coronary artery disease, valvular heart disease, renal failure, hepatic failure, active hepatobiliary disease, active infectious disease, malignancy and immunological disorder, patients who were receiving systemic agents for treatment of BD, which may potentially interfere with measurement of endocan and endothelial dysfunction. In both groups, ophthalmologic examination was performed, including visual acuity, measurement of intraocular pressure, biomicroscopical and fundus examination. All patients were evaluated by optic coherence tomography. In all patients, fluorescein angiography data during their first admissions and when available, during follow-up examinations were recorded. Ethical approval was obtained from the Medical Ethics Committee of Ataturk University Medical Faculty and written informed consents were received from all participants in accordance with the principles of the Declaration of Helsinki.
Ten milliliters of peripheral venous blood samples were obtained from all patients and sent to the laboratory for processing. The samples were centrifuged for 10 minutes at 1000 x g and then stored at -80 [degrees]C until processing. Serum concentrations of VEGF were measured using an enzyme-linked immunosorbent assay (ELISA) reader (Power Wave XS; Bio-Tek, Massachusetts, USA) and ELISA kit (eBioscience; lot no: 110047021) according to the manufacturer's standard protocol. Serum VEGF levels were calculated as pg/mL. (21) Serum concentrations of endocan were measured by an ELISA reader (Power Wave XS; Bio-Tek, Massachusetts, USA) and ELISA kit (Sunred Biological Technology; lot no: 201505) according to the manufacturer's standard protocol. The endocan levels were expressed as pg/mL. (22) Quantification of soluble tumor necrosis factor receptors 1 (sTNFR1) in serum samples was performed using ELISA kits (R&D Systems, Wiesbaden, Germany, Catalogue Numbers DY225, DY726, DY210, DY206, respectively) following the manufacturer's protocol. The detection limit was 10 pg/mL for all measurements. (23)
Statistical analyses were performed using SPSS for Windows version 11.5 (SPSS Inc., Chicago, IL, USA). The statistical significance was calculated using the independent samples t-test. P<0.05 was considered statistically significant. We used Pearson correlation method for analysis. All results were expressed as means together with their standard deviations (mean [+ or -] standard deviation).
There was no difference between groups in mean age or sex distribution. All patients were in the active phase of the disease. Demographic characteristics and laboratory findings of all groups were listed in Table 1. Serum endocan levels were 775.2 [+ or -] 479.3 ng/mL and 275.8 [+ or -] 145.9 ng/mL in the patient and control groups. There was statistically significant difference between groups in terms of serum endocan level. VEGF levels were 1768.2 [+ or -] 900.5 pg/mL and 980.2 [+ or -] 135.3 pg/mL in the patient and control groups; the difference between groups was statistically significant. In terms of serum TNF-[alpha] level, the difference between the patient and control groups was statistically significant (22.36 [+ or -] 74.3 pg m[L.sup.-1] and 11.40 [+ or -] 16.9 pg m[L.sup.-1], respectively). In the patient group, a significant positive correlation was found between serum endocan and VEGF levels (r=0.630; p<0.001) (Figure 1). Additionally, there was a significant positive correlation between serum endocan and TNF-[alpha] levels in the patient group (r=0.713; p<0.001) (Figure 2).
The basic pathology in BD is the inflammatory process in small arteries and veins together with thrombosis as a result of vasculitis of the vaso vasorum. (24) Since increased immunoglobulins, immune complexes, complement and acute phase proteins have all been reported, the immune system is considered to be involved and activated in the course of disease. Abnormalities detected in neutrophils, endothelial cells, or both, have been suggested to be responsible for many of the clinical manifestations in BD. (25)
Endocan is a proteoglycan which is secreted by vascular endothelial cells and which can be considered as a marker of endothelial activation. (26) To the best of our knowledge, until today, only one study has been conducted which has shown that plasma endocan increased in chronic kidney disease patients and influenced all-cause mortality together with cardiovascular events. According to these results, endocan may influence both the inflammatory process and the endothelial function in the pathogenesis of many vascular disorders. (27) Balta et al. (28) have compared the serum endocan levels of patients with BD with healthy individuals. In their study, they have determined higher serum endocan levels in BD patients when compared to the control group. They suggested that expression of endocan by the vascular endothelium may be a marker for systemic immune inflammatory vasculitis characterized by endothelial dysfunction such as BD.
Expression of endocan has been described to a great extent to be strongly up-regulated in the presence of proangiogenic molecules such as VEGF-A and VEGF-C which are critical mediators involved in angiogenesis, lymphangiogenesis, and cancer progression. (29) Zhang et al. (30) suggested that endocan plays a significant role in organ-specific inflammation and may be a marker indicating endothelial cellular dysfunction. Additionally, they showed a significant relationship between endocan and VEGF.
In a recently conducted study, Abu El-Asrar et al. (31) have studied the levels of endocan and VEGF in the vitreous fluid in patients with proliferative diabetic retinopathy (PDR). In their study, they have found a significant correlation between the vascularization level of epiretinal membranes in PDR and endocan level in the vitreous fluid. Additionally, they have shown a significant positive correlation between the VEGF and endocan levels in vitreous fluid. Authors have claimed that endocan was being over-expressed in PDR patients; moreover, endocan might have been a new biomarker of angiogenesis in PDR patients. In our study, we determined a positive correlation between endocan and VEGF levels in general, in patients with BD.
Endocan has a significant role in regulation of cell adhesion, inflammatory disorders, and tumor progression. Additionally, the expression of endocan in endothelial cells is up-regulated as a response to TNF. TNF-[alpha] was shown to induce endocan expression in vitro, whereas interferongamma inhibited up-regulation of endocan which was induced by TNF-[alpha]. (32) Similarly, Voiosu et al. (33) showed that endocan expression was affected by VEGF-A, TNF-[alpha], and cytokines which are involved in pathogenetic pathways in inflammatory bowel disease.
As previously mentioned, the specific sites for production of endocan are endothelial cells. Although the exact mechanism of endocan expression in infection has not been fully clarified, the expression of endocan is up-regulated as a response to TNF-[alpha] or interleukin-1 beta in vitro. (34) The expression of endocan is up-regulated by VEGF-A, VEGF-C, and TNF-[alpha]. The amount of experimental evidence is growing, which implicates endocan as a key player in the regulation of major processes such as cell adhesion, inflammatory disorders, and tumor progression. Inflammatory cytokines such as TNF-[alpha] and proangiogenic growth factors such as VEGF, fibroblast growth factor-2, and hepatocyte growth factor/scatter factor increase the expression, synthesis or secretion of endocan in human endothelial cells. In our study, we determined that a correlation was present between endocan level and levels of VEGF and TNF-[alpha], in general. (35)
In conclusion, since its cloning in 1996, endocan and endothelial cell specific molecule-1 were shown to have significant roles in many pathophysiological processes including inflammatory disorders and tumor development. In our study, we determined statistically significantly higher serum endocan levels in patients with BD. Positive correlations were present between serum endocan level and levels of VEGF and TNF-[alpha]. According to these results, endocan might affect both the inflammatory process and endothelial function in the pathogenesis of BD.
Many possible mechanisms, including stimulation of endocan expression by increased plasma levels of VEGF and TNF-[alpha], may be responsible for increased serum endocan levels in patients with BD. As a conclusion, circulating endocan may be a new marker in BD patients. It may be helpful in evaluation of both the prognosis and activity of the disease. Endocan may be a marker of endothelial dysfunction and may have a functional role in endothelium-dependent pathological disorders. Whether endocan measurement can be used for follow-up of therapeutic success is a subject which needs to be investigated.
Declaration of conflicting interests
The authors declared no conflicts of interest with respect to the authorship and/or publication of this article.
The authors received no financial support for the research and/or authorship of this article.
(1.) Davatchi F, Sadeghi Abdollahi B, Chams-Davatchi C, Shahram F, Shams H, Nadji A, et al. The saga of diagnostic/classification criteria in Behcet's disease. Int J Rheum Dis 2015;18:594-605.
(2.) Cakar Ozdal MP, Yazici A, Tufek M, Ozturk F. Epidemiology of uveitis in a referral hospital in Turkey. Turk J Med Sci 2014;44:337-42.
(3.) Cartella S, Filippini M, Tincani A, Airo P. Prevalence of BehCet's disease in the province of Brescia in northern Italy. Clin Exp Rheumatol 2014;32:176.
(4.) Mat MC, Sevim A, Fresko I, Tuzun Y. BehCet's disease as a systemic disease. Clin Dermatol 2014;32:435-42.
(5.) Davatchi F. Behcet's disease. Int J Rheum Dis 2014;17:355-7.
(6.) Dogan D, Farah C. BehCet disease. Of talmologia 2002;52:23-30. [Abstract]
(7.) Ozluk E, Balta I, Akoguz O, Kalkan G, Astarci M, Akbay G, et al. Histopathologic Study of Pathergy Test in BehCet's Disease. Indian J Dermatol 2014;59:630.
(8.) Bozkirli ED, KeSkek SO, Kozanoglu I, Yucel AE. High levels of endothelial progenitor cells can be associated with thrombosis in patients with BehCet's disease. Clin Exp Rheumatol 2014;32:49-53.
(9.) Onur E, Kabaroglu C, Inanir I, Var A, Guvenc Y, Gunay O, et al. Oxidative stress impairs endothelial nitric oxide levels in BehCets' disease. Cutan Ocul Toxicol 2011;30:217-20.
(10.) Acikgoz N, ErmiS N, Yagmur J, Cansel M, Karincaoglu Y, AtaS H, et al. Elevated oxidative stress markers and its relationship with endothelial dysfunction in BehCet disease. Angiology 2011;62:296-300.
(11.) Seo K, Kitazawa T, Yoshino Y, Koga I, Ota Y. Characteristics of serum endocan levels in infection. PLoS One 2015;10:0123358.
(12.) Aparci M, Isilak Z, Uz O, Yalcin M, Kucuk U. Endocan and endothelial dysfunction. Angiology 2015;66:4889.
(13.) Balta S, Mikhailidis DP, Demirkol S, Celik T, Ozturk C, Iyisoy A. Endocan and atherosclerosis. Angiology 2015;66:490.
(14.) Wang XS, Yang W, Luo T, Wang JM, Jing YY. Serum endocan levels are correlated with the presence and severity of coronary artery disease in patients with hypertension. Genet Test Mol Biomarkers 2015;19:124-7.
(15.) Roudnicky F, Poyet C, Wild P, Krampitz S, Negrini F, Huggenberger R, et al. Endocan is upregulated on tumor vessels in invasive bladder cancer where it mediates VEGF-A-induced angiogenesis. Cancer Res 2013;73:1097-106.
(16.) Huang GW, Tao YM, Ding X. Endocan expression correlated with poor survival in human hepatocellular carcinoma. Dig Dis Sci 2009;54:389-94.
(17.) Abid MR, Yi X, Yano K, Shih SC, Aird WC. Vascular endocan is preferentially expressed in tumor endothelium. Microvasc Res 2006;72:136-45.
(18.) Arida A, Sfikakis PP. Anti-cytokine biologic treatment beyond anti-TNF in BehCet's disease. Clin Exp Rheumatol 2014;32:149-55.
(19.) Mesquida M, Molins B, LlorenC V, Sainz de la Maza M, Hernandez MV, Espinosa G, et al. Proinflammatory cytokines and C-reactive protein in uveitis associated with BehCet's disease. Mediators Inflamm 2014;2014:396204.
(20.) Criteria for diagnosis of BehCet's disease. International Study Group for BehCet's Disease. Lancet 1990;335:1078-80.
(21.) Gu X, Yu X, Dai H. Intravitreal injection of ranibizumab for treatment of age-related macular degeneration: effects on serum VEGF concentration. Curr Eye Res 2014;39:518-21.
(22.) Kose M, Emet S, Akpinar TS, Kocaaga M, Cakmak R, Akarsu M, et al. Serum Endocan Level and the Severity of Coronary Artery Disease: A Pilot Study. Angiology 2015;66:727-31.
(23.) Kapadia SR, Yakoob K, Nader S, Thomas JD, Mann DL, Griffin BP. Elevated circulating levels of serum tumor necrosis factor-alpha in patients with hemodynamically significant pressure and volume overload. J Am Coll Cardiol 2000;36:208-12.
(24.) Hatemi G, Seyahi E, Fresko I, Talarico R, Hamuryudan V. BehCet's syndrome: a critical digest of the 20132014 literature. Clin Exp Rheumatol 2014;32:112-22.
(25.) Mat MC, Sevim A, Fresko I, Tuzun Y. BehCet's disease as a systemic disease.Clin Dermatol 2014;32:435-42.
(26.) Su YH, Shu KH, Hu CP, Cheng CH, Wu MJ, Yu TM, et al. Serum Endocan correlated with stage of chronic kidney disease and deterioration in renal transplant recipients. Transplant Proc 2014;46:323-7.
(27.) Sarrazin S, Adam E, Lyon M, Depontieu F, Motte V, Landolfi C, et al. 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 2006;1765:25-37.
(28.) Balta I, Balta S, Koryurek OM, Demirkol S, Mikhailidis DP, Celik T, et al. Serum endocan levels as a marker of disease activity in patients with BehCet disease. J Am Acad Dermatol 2014;70:291-6.
(29.) Rennel E, Mellberg S, Dimberg A, Petersson L, Botling J, Ameur A, et al. Endocan is a VEGF-A and PI3K regulated gene with increased expression in human renal cancer. Exp Cell Res 2007;313:1285-94.
(30.) Zhang SM, Zuo L, Zhou Q, Gui SY, Shi R, Wu Q, et al. Expression and distribution of endocan in human tissues. Biotech Histochem 2012;87:172-8.
(31.) Abu El-Asrar AM, Nawaz MI, De Hertogh G, Al-Kharashi AS, Van den Eynde K, Mohammad G, et al. The angiogenic biomarker endocan is upregulated in proliferative diabetic retinopathy and correlates with vascular endothelial growth factor. Curr Eye Res 2015;40:321-31.
(32.) Sarrazin S, Adam E, Lyon M, Depontieu F, Motte V, Landolfi C, et al. 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 2006;1765:25-37.
(33.) Voiosu T, Balanescu P, BenguS A, Voiosu A, BaicuS CR, Barbu M, et al. Serum endocan levels are increased in patients with inflammatory bowel disease. Clin Lab 2014;60:505-10.
(34.) Lee W, Ku SK, Kim SW, Bae JS. Endocan elicits severe vascular inflammatory responses in vitro and in vivo. J Cell Physiol 2014;229:620-30.
(35.) Sarrazin S, Adam E, Lyon M, Depontieu F, Motte V, Landolfi C, et al. 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 2006;1765:25-37.
Ayhan KUL,  Orhan ATES,  Meltem ALKAN MELIKOGLU,  Mahir UGUR,  Nurinnisa OZTURK,  Gulsum ERKAYHAN,  Ibrahim KOCER 
 Department of Physical Medicine and Rehabilitation, Medical Faculty of Ataturk University Erzurum, Turkey
 Department of Ophtalmologia, Medical Faculty of Ataturk University Erzurum, Turkey
 Department of Biochemistry, Medical Faculty of Ataturk University Erzurum, Turkey
 Department of Ophtalmologia, Mersin Public Hospital, Mersin, Turkey
Received: May 20, 2016 Accepted: September 21, 2016 Published online: March 24, 2017
Correspondence: Ayhan Kul, MD. Ataturk Universitesi Tip Fakultesi Fiziksel Tip ve Rehabilitasyon Anabilim Dali, 25240 Yakutiye, Erzurum, Turkey.
Tel: +90 442-344 70 87 e-mail: firstname.lastname@example.org
Caption: Figure 1. Correlation between serum endocan and vascular endothelial growth factor levels in patient group. A significant positive correlation was found between serum endocan and vascular endothelial growth factor levels (r= 0.630; p<0.001). VEGF: Vascular endothelial growth factor.
Caption: Figure 2. Correlation between serum endocan and tumor necrosis factor-alpha levels in patient group. A significant positive correlation was found between serum endocan and vascular endothelial growth factor levels (r=0.713; p<0.001). TNF-alpha: Tumor necrosis factor-alpha.
Table 1. Demographic characteristics and laboratory findings of study groups Patients group (n=40) % Mean [+ or -] SD Age (year) 37.6 [+ or -] 8.7 Male 60 Endocan level, 775.2 [+ or -] 479.3 (ng/mL) Vascular 1768.2 [+ or -] 900.5 endothelial growth factor level, (pg/mL) Tumor necrosis 22.4 [+ or -] 74.3 factor-alpha, (pg/m[L.sup.-1]) Control group (n=40) p % Mean [+ or -] SD Age (year) 38.8 [+ or -] 7.9 >0.05 Male 55 >0.05 Endocan level, 275.8 [+ or -] 145.8 <0.001 (ng/mL) Vascular 980.2 [+ or -] 135.3 <0.001 endothelial growth factor level, (pg/mL) Tumor necrosis 11.4 [+ or -] 16.9 <0.001 factor-alpha, (pg/m[L.sup.-1]) SD: Standard deviation; p<0.001 was considered as statistically significant between patient and control groups.
|Printer friendly Cite/link Email Feedback|
|Title Annotation:||ORIGINAL ARTICLE|
|Author:||Kul, Ayhan; Ates, Orhan; Melikoglu, Meltem Alkan; Ugur, Mahir; Ozturk, Nurinnisa; Erkayhan, Gulsum;|
|Publication:||Turkish Journal of Rheumatology|
|Date:||Sep 1, 2017|
|Previous Article:||Cartilage Oligomeric Matrix Protein Levels in Synovial Fluid in Patients With Primary Knee Osteoarthritis and Healthy Controls: A Preliminary...|
|Next Article:||Evaluation of Tryptophan/Kynurenine Pathway Relevance With Immune System Biomarkers of Low Energy Trauma Hip Fractures in Osteoporotic Patients.|