Serum Apelin Levels Research Articles

Correlation of serum apelin level with coronary calcium score in patients with suspected coronary artery disease

Introduction A growing body of evidence indicates that apelin, a relatively recent member of the adipokines family, has a potential anti-atherogenic effect. An association between low serum apelin state and coronary artery disease (CAD) was previously reported; however, the relationship between apelin and the atherosclerotic burden was unclear. Objectives Our aim was to explore the correlation of serum apelin level with coronary calcium score (CCS) as a quantitative marker of coronary atherosclerosis. Methods This observational cross-sectional study enrolled 100 consecutive subjects referred for cardiac multi-detector computed tomography (MDCT) for assessment of CAD (mean age 54 ± 9.7 years, 51 male and 49 females). Clinical parameters, glycemic and lipid profile, high sensitivity CRP (hsCRP), homeostasis model assessment of insulin resistance (HOMA-IR), serum creatinine and complete blood count were assessed. Serum apelin levels were determined using a commercially available Enzyme Immunoassay (EIA) Kit. High resolution non contrast CT images were acquired by a 64-raw MDCT and CCS was calculated using the Agatston scoring method. Results Forty three percent of the studied subjects had positive coronary artery calcification (CAC). The mean CCS was 79 ± 196.5 Agatston units. Subjects with detectable CAC had significantly higher fasting plasma glucose, HbA1c and WBCs count than subjects without detectable CAC (p 0.05). Most importantly, subjects with detectable CAC had significantly lower serum apelin level than subjects without CAC (1.3 ± 0.4 ng/ml vs. 2.8 ± 0.6 ng/ml, p 0.001). In addition, there was a statistically significant inverse correlation between serum apelin levels and CCS (r = 0.591, p 0.001); on multivariate analysis this correlation was found to be independent of traditional cardiovascular risk factors and hs-CRP. Conclusion To the best of our knowledge, this is the first report of an independent association between apelin and CCS in patients with suspected CAD. Apelin emerges as a possible novel biomarker for CAD, but this result remains to be proved prospectively.

Apelin levels in relation with hormonal and metabolic profile in patients with polycystic ovary syndrome

ObjectiveTo evaluate serum concentrations of apelin in relation to the hormonal and metabolic profile in patients with and without polycystic ovary syndrome (PCOS). Study designA total of 45 women with PCOS and 45 age-matched controls were eligible for the study. Hirsutism scores, hormonal and metabolic profile as well as apelin levels were evaluated in each subject. ResultsWomen with PCOS exhibited lower serum concentrations of apelin than controls (194.1±50.7pg/ml versus 292.1±85.6pg/ml, p<0.001). Apelin levels were significantly correlated positively with body mass index (BMI), insulin, triglyceride (TG), free testosterone (fT) levels, modified Ferriman Gallwey scores and Homeostasis Model Assessment (HOMA) index; but negatively correlated with high density lipoprotein (HDL) levels in patients with PCOS (p<0.05). When overweight or obese (BMI≥25) and normal weight (BMI<25) women with PCOS were compared to BMI-matched controls, lower apelin levels were found in the PCOS group (226.7±45.4pg/ml versus 378.6±80.9pg/ml and 165.5±36.1 versus 249.0±46.6pg/ml, p<0.001, respectively). ConclusionThe data suggest that serum apelin levels are lower in women with PCOS than in controls. Furthermore, apelin can be used as a specific marker for insulin sensitivity and lipid profile and this adipokine might play a role in the pathogenesis of PCOS.

Circulating Apelin is increased in patients with type 1 or type 2 diabetes and is associated with better glycaemic control

Apelin is an adipokine expressed in several tissues and it appears to be involved in energy metabolism. The aim of this study was to determine serum apelin levels in a large cohort of patients with type 1 and type 2 diabetes and control subjects and to correlate the results with glycaemic control. One hundred and thirty patients with type 1 diabetes, 98 patients with type 2 diabetes and 162 controls were enrolled in the study. Apelin levels were measured by enzyme-linked immunosorbent assay. Serum apelin levels were significantly higher in type 1 and type 2 diabetic patients than in controls (P<0·0001). Serum apelin levels were higher in type 1 than in type 2 diabetic patients (P=0·02). In multivariate analysis, serum apelin levels were higher in patients with type 1 diabetes and in patients with type 2 diabetes versus controls. We found a negative correlation between glycosylated haemoglobin and serum apelin levels in all diabetic patients (r=-0·17, P=0·008) and in patients with type 2 diabetes (r=-0·24 P=0·01). No correlation was found in type 1 diabetic patients. Our study showed that apelin concentrations were increased in diabetic patients. This rise, which was greater in type 1 than in type 2 diabetic patients, suggests that obesity is not the main determinant of plasma apelin levels. The negative correlation with glycosylated haemoglobin in patients with type 2 diabetes could indicate that apelin plays a role in glycaemic balance and even insulin sensitivity.

Assessment of serum apelin and lipocalin-2 levels in patients with subclinical hypothyroidism

ObjectivesSubclinical hypothyroidism is the precursor to hypothyroidism because it has a tendency to transform into hypothyroidism. Subclinical hypothyroidism is considered one of the risk factors causing metabolic syndrome. Metabolic syndrome can be characterized by plasma levels of apelin and lipocalin-2, both released from adipocytes. In the present study, we aimed to measure serum apelin and lipocalin-2 levels of patients with subclinical hypothyroidism and compare them with serum apelin and lipocalin-2 levels from healthy individuals. MethodsThis was a cross-sectional study. A total of 80 subjects were enrolled in the study and divided into two groups: Group A included 39 patients (females, n=34) diagnosed with subclinical hypothyroidism, and Group B (the control group) comprised 41 healthy volunteers (females, n=38). Serum samples were obtained from each participant for the measurement of apelin and lipocalin-2. These were then stored at minus 80°C until the time of analysis, when serum apelin and lipocalin-2 levels of the two groups were compared. ResultsPatients with subclinical hypothyroidism (Group A and Group B subjects [healthy controls]) were comparable with respect to gender, age, and body mass index (BMI) (P=0.412, P=0.863, and P=0.269, respectively), nor was there a statistically significant difference between groups in terms of apelin and lipocalin-2 levels (P=0.87, and P=0.67, respectively). Apelin levels showed a positive and significant correlation with BMI (P=0.034). Serum lipocalin-2 levels showed significant positive correlations with BMI and creatinine levels (P=0.002, and P=0.025, respectively). ConclusionIn the present study, no significant difference of serum apelin and lipocalin-2 levels was observed between patients with subclinical hypothyroidism and healthy control subjects. Positive correlations were found, however, between serum apelin level and BMI as well as between serum lipocalin-2 and BMI and creatinine levels.

Effect of Ramadan fasting on serum concentration of apelin-13 and new obesity indices in healthy adult men

BackgroundThe aim of this study was to determine how Ramadan fasting (RF) affected the recently described new obesity indices [visceral adiposity index (VAI), waist circumference to height ratio (WHtR), body adiposity index (BAI)], and serum concentration of apelin-13 (RF) in healthy adult men.Material/MethodsFor this purpose, 42 healthy adult men were selected. Anthropometric parameters were measured and a sample of venous blood was obtained for biochemical assays on the first and last days of Ramadan.When all subjects were evaluated, all anthropometric parameters changed except VAI. Serum apelin-13, triglyceride (TG), HDL-cholesterol (HDL-C), and insulin levels did not change. When patients were divided into 3 groups according to body mass index (BMI), BAI decreased in normal-weight subjects and WHtR decreased in other groups, but VAI and apelin-13 did not change in any groups.ResultsWe demonstrate for the first time that while some anthropometric parameters changed, VAI and serum apelin-13 levels did not change with RF. BMI, waist circumference (WC), TG, and HDL-C were evaluated together in calculation of VAI. TG, VAI, and HDL-C remained unchanged by RF. Even if body weight (BW) and BMI decreased, apelin-13 was not affected by RF. The data on serum apelin-13 may have been influenced by the small-percentage decrease in BW, as well as insignificant improvements in metabolic parameters such as lipid profiles, glucose, and insulin.ConclusionsWe found that Ramadan fasting in healthy adult men was associated with significant decreases in BW, BMI, WHtR, and BAI, but we found no significant changes in VAI and serum apelin-13 concentrations.

Does polycystic ovary syndrome itself have additional effect on apelin levels?

Objective. The present study was designed to compare serum levels of apelin between lean PCOS women and healthy women with regular menses. Study Design. A total of 30 lean patients with PCOS and 30 healthy subjects were included in this study. Serum apelin levels were compared between groups. Results. Serum apelin levels in lean PCOS patients were not significantly different from the control subjects. Conclusion. Our findings indicate that PCOS itself does not seem to change apelin levels. Further investigation on a large number of subjects will need to be conducted to prove the consistent or variable association in PCOS.

Serum levels of resistin, adiponectin, and apelin in gastroesophageal cancer patients.

The aim of the study was the investigation of relationship between cachexia syndrome and serum resistin, adiponectin, and apelin in patients with gastroesophageal cancer (GEC). Material and Methods. Adipocytokines concentrations were measured in sera of 85 GEC patients and 60 healthy controls. They were also evaluated in tumor tissue and appropriate normal mucosa of 38 operated cancer patients. Results. Resistin and apelin concentrations were significantly higher in GEC patients than in the controls. The highest resistin levels were found in cachectic patients and in patients with distant metastasis. Serum adiponectin significantly decreased in GEC patients with regional and distant metastasis. Serum apelin was significantly higher in cachectic patients than in the controls. Apelin was positively correlated with hsCRP level. Resistin and apelin levels increased significantly in tumor tissues. Weak positive correlations between adipocytokines levels in serum and in tumor tissue were observed. Conclusions. Resistin is associated with cachexia and metastasis processes of GEC. Reduction of serum adiponectin reflects adipose tissue wasting in relation to GEC progression. Correlation of apelin with hsCRP can reflect a presumable role of apelin in systemic inflammatory response in esophageal and gastric cancer.

The effect of chromium picolinate supplementation on the pancreas and macroangiopathy in type II diabetes mellitus rats.

Purpose. The aim was to explore the effect of the chromium picolinate (CrPic) administration on the pancreas and macroangiopathy of type II diabetes mellitus rats. Methods. The type II diabetes mellitus (T2DM) rat model was induced by low-dose streptozotocin (STZ). The rats were randomly divided into 5 groups (ten rats in each group). After supplementing CrPic for 15 weeks, the histopathological examination was performed by hematoxylin-eosin (HE) staining. Serum insulin and NO level were determined by radioimmunoassay and colorimetry, respectively. Serum glycosylated hemoglobin (HbA1C), adiponectin (APN), advanced glycation end products (AGES), and apelin were measured by ELISA. Real-time reverse transcription polymerase chain reaction (RT-PCR) was applied for detecting the mRNA expression of APN and apelin. Results. After CrPic treatment, compared with the T2DM control group (group 2), pancreas sections stained with HE showed the completed pancreatic cells structure and no inflammatory infiltration in groups 4 and 5. In addition, the levels of serum NO and insulin were significantly increased and the serum levels of HbA1C, AGES, APN, and apelin were significantly decreased in groups 4 and 5 compared with group 2. The mRNA expression of APN and apelin in groups 4 and 5 was also recovered to the normal level. Conclusion. CrPic can recover the function of Β-cells and alleviate macroangiopathy in STZ-induced T2DM rats.

Study of Some Cytokines and Hormones in a Sample of Iraqi women with Polycystic ovarian syndrome and Their Relation to Obesity.

The present study aimed to measure serum vaspin and apelin levels in women with PCOS to show their rule in the pathogenesis of PCOS. Ninety eight women with PCOS, 51 non-obese [body mass index (BMI) less than 25 kg/m2] and 47 obese (BMI &gt;25 kg/m2) were enrolled in the study. Each group is compared to apparently healthy women as a control group matched for age and BMI. Clinical history, anthropometric measurements and biochemical and hormonal analysis were determined. The mean serum level of vaspin and apelin showed statistically significant difference between PCOS patients (non-obese and obese) compared to control women (non-obese and obese) respectively. Also, the levels of both parameters (vaspin, apelin)showed significant differences between PCOS obese patients and non-obese ones. It is concluded that serum vaspin and apelin level increased in PCOS women particularly the obese. These data suggest their involvement in the pathogenesis of PCOS

Apelin could reduce risk of contrast-induced nephropathy in patients with congestive heart failure

Compared to the normal population, patients with congestive heart failure are at higher risk for contrast-induced nephropathy. A variety of interventions are suggested to reduce the risk for contrast-induced nephropathy. Unfortunately results of none of current protective treatments are satisfactory. Apelin a vasodilator adipocytokine, positively inotropic agent, and free radical scavenger has been recently introduced. It has been shown that endogenous apelin levels are decreased in patients with congestive heart failure.Two major mechanisms have been suggested for pathophysiology of contrast induced nephropathy including reactive oxygen species production and impaired renal perfusion due to vasoconstriction.Pretreatment with recombinant apelin (exogenous apelin-13), could compensate decreased endogenous apelin serum levels of congestive heart failure patients. Its antioxidant and cell-protective properties, decrease nephrotoxicity of contrast agent; additionally impaired renal perfusion due to malfunction of cardiac pump will refurbish, because of positively inotropic property of apelin plus its vasodilatation effect in renal arteries. We believe that the triangle of increased contractility, decreased vascular resistance and decreased contrast agent nephrotoxicity could significantly reduce risk of contrast-induced nephropathy in patients with congestive heart failure.

Aldosterone directly affects apelin expression and secretion in adipocytes

There is a high incidence of metabolic syndrome among patients with primary aldosteronism (PA), which has recently been associated with an unfavorable cardiometabolic profile. However, the underlying mechanisms have not been clarified in detail. Characterizing aldosterone (Ald) target genes in adipocytes will help us to elucidate the deleterious effects associated with excess Ald. Apelin, a novel adipokine, exerts beneficial effects on obesity-associated disorders and cardiovascular homeostasis. The objective of this study was to investigate the effects of high Ald levels on apelin expression and secretion and the underlying mechanisms involved in adipocytes. In vivo, a single-dose Ald injection acutely decreased apelin serum levels and adipose tissue apelin production, which demonstrates a clear inverse relationship between the levels of plasma Ald and plasma apelin. Experiments using 3T3-L1 adipocytes showed that Ald decreased apelin expression and secretion in a time- and dose-dependent manner. This effect was reversed by glucocorticoid receptor (GR) antagonists or GR (NR3C1) knockdown; furthermore, putative HREs were identified in the apelin promoter. Subsequently, we verified that both glucocorticoids and mineralocorticoids regulated apelin expression through GR activation, although no synergistic effect was observed. Additionally, detailed potential mechanisms involved a p38 MAPK signaling pathway. In conclusion, our findings strengthen the fact that there is a direct interaction between Ald and apelin in adipocytes, which has important implications for hyperaldosteronism or PA-associated cardiometabolic syndrome and hoists apelin on the list of potent therapeutic targets for PA.

Serum apelin levels in systemic sclerosis

Serum apelin levels in systemic sclerosis

Evaluation of Adipokines: Apelin, Visfatin, and Resistin in Children with Atopic Dermatitis

Very little is known about the role of adipokines in atopic dermatitis (AD) in children. This study aimed at analyzing the serum levels of resistin, apelin, and visfatin in children with AD in relation to body weight, AD severity, and gender. Serum concentration of adipokines was measured in 27 children with AD and in 46 healthy subjects. Selected biochemical parameters were evaluated and skin prick test was performed. Serum levels of resistin and apelin were significantly higher, whereas serum visfatin concentration was significantly lower in children with AD versus healthy controls, although an increase in resistin levels was exclusively demonstrated in boys. In AD group, a significant increase in apelin levels in girls was documented. There was no relationship between adipokines levels and the degree of allergic sensitization. Receiver operating characteristic curve analysis demonstrated that the serum apelin cutoff value differentiating children with AD from those without was >137.8 pg/mL. Resistin and visfatin cutoff values were >3.8 ng/mL and ≤ 2.13 ng/mL, respectively. Apelin and visfatin can serve as excellent indicators to distinguish children with AD from those without disease.

Altered glucose homeostasis is associated with increased serum apelin levels in type 2 diabetes mellitus.

BackgroundApelin is an adipokine that plays a role in the regulation of glucose homeostasis and in obesity. The relationship between apelin serum concentration and dysmetabolic conditions such as type 2 diabetes (T2D) is still controversial. Aims of our study are: 1) determine the circulating levels of apelin in a large cohort of Italian subjects with T2D, T1D and in non-diabetic controls; 2) identify putative metabolic determinants of modified apelin concentrations, in order to search possible mechanism of apelin control; 3) investigate changes in apelin levels in response to sharp modifications of glucose/insulin metabolism in T2D obese subjects before and 3 days after bariatric surgery.MethodsWe recruited 369 subjects, 119 with T2D, 113 with T1D and 137 non-diabetic controls. All subjects underwent a complete clinical examination, including anthropometric and laboratory measurements. Serum apelin levels were determined by EIA (immunoenzyme assay).ResultsPatients with T2D had significantly higher serum apelin levels compared to controls (1.23±1.1 ng/mL vs 0.91±0.7 ng/mL, P<0.001) and to T1D subjects (0.73±0.39 ng/mL, P<0.001). Controls and T1D subjects did not differ significantly in apelin levels. Apelin concentrations were directly associated with fasting blood glucose (FBG), body mass index (BMI), basal Disposition Index (DI-0), age, and diagnosis of T2D at bivariate correlation analysis. Multiple regression analysis confirmed that diagnosis of T2D, basal DI-0 and FBG were all determinants of serum apelin levels independently from age and BMI. Bariatric surgery performed in a subgroup of obese diabetic subjects (n = 12) resulted in a significant reduction of apelin concentrations compared to baseline levels (P = 0.01).ConclusionsOur study demonstrates that T2D, but not T1D, is associated with increased serum apelin levels compared to non-diabetic subjects. This association is dependent on impaired glucose homeostasis, and disappears after bariatric surgery, providing further evidence regarding the relationship between apelin and the regulation of glucose metabolism.

Adipokines: a novel link between adiposity and carotid plaque vulnerability

In patients with carotid stenosis, we prospectively investigated the association of novel adipokines, apelin and visfatin, with gray-scale median (GSM) score, a valid index of carotid plaque vulnerability. We also assessed the impact of atorvastatin therapy on the above biochemical and imaging markers. Seventy-four overweight [body-mass index (BMI) > 25 kg/m(2) , fat-mass > 30%], statin-free patients, with carotid stenosis, but without indications for intervention were enrolled. Thirty-eight age-, sex- and BMI-matched healthy subjects served as healthy controls (HC). All patients received gradual titrated (10-80 mg) atorvastatin therapy to target LDL-C < 100 mg/dL. GSM score, blood pressure (BP), fat-mass, lipid profile, and serum high-sensitivity C-reactive protein (hsCRP), apelin and visfatin levels were obtained at baseline and after 24 months. At baseline, patients with carotid atherosclerosis had worse lipid profile, lower apelin and higher systolic BP, hsCRP, visfatin levels compared with HC (P < 0·05). Notably, decreased apelin (P < 0·001) and GSM score (P = 0·010), while increased visfatin (P = 0·019) and hsCRP (P = 0·039) levels were found in symptomatic rather than asymptomatic patients. At baseline, GSM score correlated with fat-mass, BMI, LDL-C, visfatin and apelin (P < 0·05). Apelin, visfatin and fat-mass remained independent determinants of baseline GSM score (R(2) = 0·391, P = 0·007). In parallel, we found that apelin increment and LDL-C reduction were independently associated with the atorvastatin-induced GSM increase (R(2) = 0·411, P = 0·011). Increased fat-mass, low apelin and high visfatin serum levels seem to correlate with carotid plaque vulnerability in patients with carotid stenosis. The atorvastatin-induced modification of apelin and LDL-C may beneficially affect carotid plaque stability.

Serum levels of apelin, salusin-alpha and salusin-beta in normal pregnancy and preeclampsia

Objective: The purpose of this study was to investigate the relationship between the serum apelin, salusin-alpha and salusin-beta levels and preeclampsia. Method: Twenty-one healthy pregnant women (control group) and 48 patients with preeclampsia (study group) were included in the study between August 2010 and February 2011. Serum apelin, salusin-alpha and salusin-beta levels of the groups were compared. Results: The patients in the study group were divided into two categories: mild preeclampsia and severe preeclampsia. The mild preeclampsia group consisted of 31 patients, and the severe preeclampsia group consisted of 17 patients. Serum salusin-alpha and salusin-beta levels of the control and study groups were not significantly different (p > 0.05). Apelin levels were statistically significantly higher in the study group. No statistically significant difference was detected between the mild and severe preeclampsia groups in terms of the mean serum apelin levels. Conclusion: The serum levels of apelin were higher in the pregnant women with preeclampsia; however, there was no positive relationship between serum salusin-alpha and salusin-beta levels and the disease. Larger prospective studies are needed to validate our findings.

Serum asymmetric dimethylarginine, apelin, and tumor necrosis factor-α levels in non-obese women with polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is associated with multiple risk factors for cardiovascular disease (CVD), including insulin resistance, type 2 diabetes mellitus, obesity, hypertension, and dyslipidemia. In addition, hyperandrogenism may contribute to the pathogenesis of CVD, independent of obesity and insulin resistance. We investigated serum levels of asymmetric dimethylarginine (ADMA), apelin, and tumor necrosis factor (TNF)-α as CVD risk markers and their relationship with hyperandrogenism in non-obese women with PCOS. In this study were included 82 non-obese women with PCOS and 33 controls. Women with PCOS were further divided into two groups: women with hyperandrogenism (HA-PCOS, n=37) and those without hyperandrogenism (NA-PCOS, n=45). Serum ADMA, apelin, and TNF-α levels were compared among the three groups and their relationship with hyperandrogenism was evaluated. Serum ADMA levels were significantly higher in the HA-PCOS group than in the NA-PCOS and control groups (0.45±0.09 vs. 0.38±0.08 vs. 0.40±0.07; P<0.0005). Serum TNF-α levels were significantly higher among women with PCOS compared with controls (2.91±1.25 vs. 1.74±0.77; P<0.001) and in the HA-PCOS group compared with the NA-PCOS group (3.21±1.24 vs. 2.60±1.24; P<0.0001). Both PCOS groups had significantly lower serum apelin levels compared with controls (1.31±0.54 vs. 1.16±0.34 vs. 2.78±1.10; P<0.0001). ADMA and TNF-α were positively correlated with total testosterone (r=0.219, P=0.022; r=0.332, P<0.001, respectively) and free androgen index (r=0.287, P=0.002; r=0.289, P=0.002, respectively), whereas apelin was negatively correlated with these parameters (r=−0.362, P<0.001; r=−0.251, P=0.008). These findings may indicate that non-obese women with PCOS are at an increased risk for CVD, which is further aggravated by hyperandrogenism.

Serum levels of apelin, salusin-alpha and salusin-beta in normal pregnancy and preeclampsia

Objective: The purpose of this study was to investigate the relationship between the serum apelin, salusin-alpha and salusin-beta levels and preeclampsia. Method: Twenty-one healthy pregnant women (control group) and 48 patients with preeclampsia (study group) were included in the study between August 2010 and February 2011. Serum apelin, salusin-alpha and salusin-beta levels of the groups were compared. Results: The patients in the study group were divided into two categories: mild preeclampsia and severe preeclampsia. The mild preeclampsia group consisted of 31 patients, and the severe preeclampsia group consisted of 17 patients. Serum salusin-alpha and salusin-beta levels of the control and study groups were not significantly different (p > 0.05). Apelin levels were statistically significantly higher in the study group. No statistically significant difference was detected between the mild and severe preeclampsia groups in terms of the mean serum apelin levels. Conclusion: The serum levels of apelin were higher in the pregnant women with preeclampsia; however, there was no positive relationship between serum salusin-alpha and salusin-beta levels and the disease. Larger prospective studies are needed to validate our findings.

Increasing of serum apelin level in patients with metabolic syndrome

The changes of serum apelin in patients with metabolic syndrome were investigated. The level of fasting serum apelin was determined by ELISA assay.The level of serum apelin was raised obviously in patients with metabolic syndrome(MS).Moreover,the level of serum apelin in patients with type 2 diabetes mellitus was higher than those in cases of MS with impaired glucose regulation and the group of subjects with overweight/obesity [ (475.8±37.3 vs 451.5±54.3 and 430.3±52.1 ) ng/L,P＜0.01 ].In a multiple step-wise regression analysis,In homeostasis model assessment of insulin resistance ( HOMA-IR),body mass index,and total cholesterol were independent factors of apelin.The increased serum apelin was closely related to metabolic abnormalities in metabolic syndrome.The increased insulin resistance might cause the raised level of serum apelin in patients with MS. Key words: Apelin; Metabolic syndrome; Insulin resistance; Diabetes mellitus, type 2

Serum Levels of Asymmetric Dimethylarginine and Apelin as Potential Markers of Vascular Endothelial Dysfunction in Early Rheumatoid Arthritis

Objectives. Impaired endothelial function represents the early stage of atherosclerosis, which is typically associated with systemic inflammatory diseases like rheumatoid arthritis (RA). As modulators of endothelial nitric oxide synthase expression, asymmetric-dimethylarginine (ADMA) and apelin might be measured in the blood of RA patients to detect early atherosclerotic changes. We conducted a prospective, case-control study to investigate serum ADMA and apelin profiles of patients with early-stage RA (ERA) before and after disease-modifying antirheumatic drug (DMARD) therapy. Methods. We enrolled 20 consecutively diagnosed, treatment-naïve patients with ERA and 20 matched healthy controls. Serum ADMA and apelin levels and the 28-joint disease activity scores (DAS28) were assessed before and after 12 months of DMARDs treatment. All patients underwent ultrasonographic assessment for intima-media tickness (IMT) evaluation. Results. In the ERA group, ADMA serum levels were significantly higher than controls at baseline (P = 0.007) and significantly decreased after treatment (P = 0.012 versus controls). Baseline serum apelin levels were significantly decreased in this group (P = 0.0001 versus controls), but they were not significantly altered by treatment. IMT did not show significant changes. Conclusions. ERA is associated with alterations of serum ADMA and apelin levels, which might be used as biomarkers to detect early endothelial dysfunction in these patients.