| Objective:Essential hypertension (essential hypertension, EH) is a common cardiovascular disease. The long-term course and accompanying risk factors of EH patients are associated with main artery remodeling, resulting in damage to the arterial structure and function. Arterial wall thickness and lesion can be directly measured by high-frequency ultrasound, thus early atherosclerotic lesions can be detected. As an early indicator of atherosclerosis, the increased carotid intima-media thickness (intima-media thickness, IMT) has been well recognized, and ultrasonic monitoring of carotid IMT has become a clinical method to predict target organ damage in essential hypertension patients.With the progression of hypertension, the cardiovascular system expericences a series of changes in form, structure and function, which is called remodeling. In a broad way, remodeling refers to structural remodeling and functional remodeling, and structural remodeling mainly refers to left ventricular hypertrophy. Recent studies have demonstrated that cardiovascular remodeling is closely related to the prognosis of hypertension. Echocardiography can accurately measure the left ventricular mass index (left ventricular mass index, LVMI), in order to accurately assess left ventricular remodeling (left ventricular remodeling, LVR).YKL-40, also known as human cartilage glycoprotein-39 (HC-gp39) and chitinase 3 like 1 (chtinase-3-like-1 protein), is a glycoprotein belongs to chitinase-like family of proteins, and is secreted by multiple cells, including differentiated vascular smooth muscle cells, cartilage cells and fibroblast-like in arthritis, activated macrophages, late differentiated macrophages, and neutrophils. YKL-40 is mainly involved in the innate immune system activation and remodeling of the extracellular matrix. In vivo, YKL-40 is expressed in smooth muscle cells of different inflamed tissue, human vascular adventitia, macrophages subpopulation, vascular smooth muscle cells in atherosclerotic plaques and atherosclerotic plaque remodeling matrix. YKL-40 is a good independent predictor of plaque lesions, and high levels of YKL-40 affects the arterial compliance, and may be a new index to observe subclinical target organ damage in hypertensive patients.Studies on correlation of serum YKL-40 levels with carotid intima-media thickness and left ventricular remodeling in patients with essential hypertension are few, and this study aims to explore it, providing a reliable basis for clinical treatment and prognosis.Methods:199 patients (54 male and 45 female) first diagnosed as essential hypertension in the Second Hospital of Hebei Medical University from January 2014 to December 2014 were enrolled in this study. The diagnosis was made in accordance with 2010 Chinese Hypertension Prevention Guide: systolic blood pressure≥ 140mmHg and (or) diastolic blood pressure> 90mmHg (1mmHg=0.133kPa).33 subjects were in the control group, all of whom were from the hospital medical center, and their physical examinations were normal. All the patients had their medical history recorded and had a physical examination conventionally. Serum lipids, liver function, kidney function and other biochemical markers of the patients were tested, in addition, carotid artery ultrasonography and echocardiography were conducted. Serum YKL-40 levels of the subjects were detected by immunohistochemical staining. Exclusion criteria:① older than 70 years ② secondary hypertension ③ accompanying with coronary heart disease, diabetes, cardiomyopathy, infection, metabolic diseases, autoimmune diseases and severe chronic diseases ④the uncooperative.2 Carotid IMT measurement methods:In the long axis of carotid, the maximum distance of the posterior arterial wall was measured between the interface of lumen-intima and media-adventitia at ECG R-wave vertex. The measuring position included distal carotid artery, carotid artery bifurcation and within the scope of lcm of proximal internal carotid artery. The measurement was performed in three continuous cardiac cycles, and the average value was regarded as carotid IMT. IMT<0.9mm is normal; IMT≥0.9mm, but≤1.2mm is intimal thickening; IMT>1.2mm, local uplift thickening and protruding into the lumen, but not causing stenosis is intimal plaque formation. According to IMT, patients were divided into normal group, thickening group and plaque group.3 Echocardiography:Subjects took the left lateral decubitus position, and the examination was performed by the same sonographer. Using the method recommended by American Institute of Ultrasound in Medicine, the sonographer would measure interventricular septal thickness (IVST), left ventricular end-diastolic diameter (LVEDD), and left ventricular end-diastolic posterior wall thickness (LVPWT). The sonographer obtained all measurements in 3 cardiac cycles, then averaged the results. According to formula recommended by Devereux et al, LVMI= 1.04 [(IVST+LVPWT+LVEDD) 3-LVEDD3]-13.6/BSA (g/m2), and BSA is body surface area (m2). Left ventricular hypertrophy was defined by LVMI thresholds of 125 g/m2 for men, and 110 g/m2 for women. The patients were divided into 2 groups accroding to LVMI:LVMI normal group and LVMI increased group.4 Measurement data were presented as mean± standard deviation (x±s). T test was used to compare two means. The data were counted by one-way analysis of variance (ANOVA) followed by least significant difference (least significant difference, LSD) for pairwise comparisons with SPSS 13.0 statistical program, respectively. Values of P<0.05 were considered to be statistically significant.Results:1 Comparisons of clinical datas and serum YKL-40 levels in essential hypertension group and the control groupThere was no significant difference in age (57.38±9.84 years vs.54.18 ±10.24 years) and sex (male/female:54/45 vs.17/16) between essential hypertension group and the control group (P>0.05). Compared with the control group, BMI, TC, TG and LDL-C in essential hypertension group were increased (24.72±2.97kg/m2 vs.23.58±1.65kg/m2; 4.18±0.80mmol/L vs. 4.03±0.48mmol/L; 1.35±0.65mmol/L vs.1.04 ±0.35mmol/L; 2.65± 0.66mmol/L vs.2.54±0.36mmol/L), and the difference was statistically significant (P<0.05). Compared with the control group, HDL-C in essential hypertension group was decreased (1.17±0.32mmol/L vs.1.28 ± 0.28mmol/L), and the difference was statistically significant (P<0.05). Compared with the control group, serum YKL-40 levels in essential hypertensive patients were significantly increased (407.36±72.66ng/ml vs. 169.9±26.66ng/ml), and the difference was statistically significant (P<0.05).2 Comparisons of clinical datas and serum YKL-40 levels in normal IMT group, IMT thickening group and plaque groupThere was no significant difference in age, sex, BMI, TC, TG, LDL-C and HDL-C within the three groups (P>0.05). Compared with the normal IMT group, serum YKL-40 levels in IMT thickening group were significantly increased (448.87±64.57ng/ml vs.200.47±11.53ng/ml), and the difference was statistically significant (P<0.05). Compared with the normal IMT group, serum YKL-40 levels in plaque group were significantly increased (545.55± 77.21ng/ml vs.200.47±11.53ng/ml), and the difference was statistically significant (P<0.05). Compared with the IMT thickening group, serum YKL-40 levels in plaque group were significantly increased (545.55 ± 77.21ng/ml vs.448.87±64.57ng/ml), and the difference was statistically significant (P<0.05).3 Comparisons of clinical datas and serum YKL-40 levels in normal LVMI group and increased LVMI groupThere was no significant difference in age (male 53.9±12.9 years vs. 56.50±10.40 years; female 60.53±8.58 years vs.59.04±6.24 years), sex (male/female:20/17 vs.34/28), BMI (male 26.01±3.12kg/m2 vs.24.71± 2.56kg/m2; 24.53±3.28kg/m2 vs.23.93±2.97kg/m2), TC (male 4.09± 0.77mmol/L vs.3.96±0.58mmol/L; female 4.14±0.46mmol/L vs.4.52± 1.09mmol/L), TG (male 1.53±0.77mmol/L vs.1.39±0.81mmol/L; female 1.35±0.30mmol/L vs.1.17±0.45mmol/L), HDL-C (male 1.03±0.24mmol/L vs.1.09±0.26mmol/L; female 1.11±0.26mmol/L vs.1.40±0.37mmol/L) and LDL-C (male 2.58±0.58mmol/L vs.2.47±0.52mmol/L; female 2.74± 0.41mmol/L vs.2.87±0.90mmol/L) in normal LVMI group and increased LVMI group (P> 0.05). Compared with the normal LVMI group, serum YKL-40 levels in increased LVMI group were significantly increased (male 579.51 ±76.96ng/ml vs.261.86±53.81ng/ml; female 599.89±60.11ng/ml vs.275.6 ±58.08ng/ml), and the difference was statistically significant (P<0.05).Conclusions:In patients with essential hypertension,YKL-40 may be involved in left ventricular remodeling, endothelial dysfunction and atherosclerosis formation, causing organ damages. |
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