Danuta Fedak

Differential associations of inflammatory and endothelial biomarkers with disease activity in rheumatoid arthritis of short duration.

Objectives. To estimate endothelial dysfunction in patients with rheumatoid arthritis (RA) of short duration in relation to disease activity based on the assessment of 28 joints (DAS28). Methods. We studied 29 patients (22 women, mean age 41 (SD, 9) years) with RA of short duration and 29 healthy controls. The RA subjects were divided into those with low (DAS28: 2.6–5.1, n = 18) or high (DAS28 > 5.1, n = 11) disease activity. Exclusion criteria included clinically overt atherosclerosis and other coexistent diseases. Biochemical markers of inflammatory activation and endothelial dysfunction were measured. Results. There were no significant intergroup differences in the majority of classical cardiovascular risk factors. High-sensitivity C-reactive protein, tumor necrosis factor-α, and interleukin-6 were increased in RA subjects. Compared to the controls, levels of soluble vascular cell adhesion molecule-1, von Willebrand factor, and pentraxin-3 were significantly elevated in RA subjects with low disease activity, exhibiting no further significant rises in those with high disease activity. Asymmetric dimethyl-L-arginine, soluble E-selectin, monocyte chemotactic protein-1, and osteoprotegerin were increased only in RA patients with high disease activity. Conclusions. Our findings might suggest a dissociation of pathways governing generalized and joint-specific inflammatory reactions from those involved in endothelial activation and inflammation within the vascular wall.

Osteoprotegerin, but not osteopontin, as a potential predictor of vascular calcification in normotensive subjects

We conducted a cross-sectional observation study that included 500 asymptomatic subjects to investigate the relationship between bone metabolism and coronary artery calcification (CAC) in hypertensive conditions. Osteoprotegerin (OPG) and osteopontin (OPN) levels and their associations with hypertension were analyzed to predict CAC in 316 subjects. Multislice computed tomography was used to quantify CAC. Multivariate analysis of variance was used to test the non-interactive effects of hypertension, CAC severity and biomarker levels, and the logistic regression model was applied to predict the risk of CAC. OPG and OPN concentrations were significantly higher in the hypertensive than the normotensive subjects, at 3.0 (2.3–4.0) pmol l−1 and 51 (21–136) ng ml−1 vs. 2.4 (2.0–3.0) pmol l−1 and 41 (13–63) ng ml−1, respectively. The OPG level, but not OPN level, increased with age (r=0.29; P=0.0001). Zero or minimal CAC (<10 Agatston units (AU)) was observed in 63% of the subjects, mild (11–100 AU) in 17%, moderate (101–400 AU) in 12% and severe (401–1000 AU)-to-extensive (>1000 AU) in 8%. In hypertensive subjects, only glomerular filtration rate (GFR) (β=−0.67) and gender (β=0.52) were significant predictors for CAC (R=0.68). In normotensive patients, GFR (β=−0.81), gender (β=0.48) and log-transformed OPG levels (β=0.15) were significant predictors for CAC. OPG levels were associated with an increased risk of CAC in normotensive subjects only (odds ratio: 3.37; 95% confidence interval (1.63–6.57); P=0.0002). OPG predicted a premature state of vascular calcification in asymptomatic normotensive individuals, and renal function significantly contributed to this process in both hypertensive and normotensive subjects.

Markers of Antioxidant Defense in Patients with Type 2 Diabetes.

Aims. Diabetes is considered a state of increased oxidative stress. This study evaluates blood concentrations of selected markers of antioxidant defense in patients with type 2 diabetes. Methods. The study included 80 type 2 diabetes patients and 79 apparently healthy controls. Measured markers included ferric reducing ability of plasma (FRAP), reduced glutathione (GSH), glutathione peroxidase (GPx), glutathione reductase (GR), γ-glutamyltransferase (GGT) and uric acid serum, and plasma and/or hemolysate levels. Results. FRAP, uric acid, CRP, and GGT levels were significantly higher in patients with diabetes. Plasma and hemolysate GR was significantly higher whereas GPx activity was significantly lower in patients with diabetes. There were no significant differences in antioxidant defense markers between patients with and without chronic diabetes complications. Fasting serum glucose correlated with plasma GPx, plasma and hemolysate GR, FRAP, and serum GGT, and HbA1c correlated with serum GGT. Only FRAP and serum uric acid were significantly higher in obese (BMI > 30 kg/m2) patients with diabetes than in nonobese patients. Conclusions. Some components of antioxidant defense such as GR, uric acid, and GGT are increased in patients with type 2 diabetes. However, the whole system cannot compensate for an enhanced production of ROS as reflected by the trend toward decreased erythrocytes GSH.

Vascular Effects of Advanced Glycation End-Products: Content of Immunohistochemically Detected AGEs in Radial Artery Samples as a Predictor for Arterial Calcification and Cardiovascular Risk in Asymptomatic Patients with Chronic Kidney Disease

Objectives. Our aim was to determine whether vascular deposition of advanced glycation end-products (AGEs) is associated with arterial calcification and cardiovascular mortality in chronic kidney disease (CKD) patients and to assess the relationships between vascular content of AGEs and selected clinical and biochemical parameters. Materials and Methods. The study comprised 54 CKD patients (33 hemodialyzed, 21 predialyzed). Examined parameters included BMI, incidence of diabetes, plasma fasting glucose, AGEs, soluble receptor for AGEs and 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging, serum C-reactive protein (hsCRP), plasminogen activator inhibitor-1 (PAI-1), and fetuin-A. Fragments of radial artery obtained during creation of hemodialysis access were stained for calcifications using alizarin red. AGEs deposits were identified immunohistochemically and their relative content was quantified. Results. Vascular content of AGEs was positively correlated with BMI, hsCRP, fetuin-A, PAI-1, and DPPH scavenging in simple regression; only fetuin-A was an independent predictor in multiple regression. There was a significant positive trend in the intensity of AGEs immunostaining among patients with grades 1, 2, and 3 calcifications. AGEs immunostaining intensity predicted 3-year cardiovascular mortality irrespective of patients age. Conclusions. The present study demonstrates an involvement of AGEs in the development of medial arterial calcification and the impact of arterial AGE deposition on cardiovascular mortality in CKD patients.

Impaired Fasting Glucose and Diabetes as Predictors for Radial Artery Calcification in End Stage Renal Disease Patients

Objective. The objective of the study was to assess the relationship between selected clinical and biochemical parameters of end stage renal disease (ESRD) patients and arterial calcification. Materials and Methods. The study comprised 59 stage 5 chronic kidney disease patients (36 hemodialyzed and 23 predialysis). The examined parameters included common carotid artery intima-media thickness (CCA-IMT), BMI, incidence of diabetes and impaired fasting glucose (IFG), dyslipidemia, hypertension, and 3-year mortality. Plasma levels asymmetric dimethylarginine (ADMA), osteopontin (OPN), osteoprotegerin (OPG), and osteocalcin (OC) were also measured. Fragments of radial artery obtained during creation of hemodialysis access were stained for calcifications using von Kossa method and alizarin red. Results. Calcification of radial artery was significantly associated with higher prevalence of IFG and diabetes (P = 0.0004) and older age (P = 0.003), as well as higher OPG (P = 0.014) and ADMA concentrations (P = 0.022). Fasting glucose >5.6 mmol/l (IFG and diabetes) significantly predicted vascular calcification in multiple logistic regression. The calcification was also associated with higher CCA-IMT (P = 0.006) and mortality (P = 0.004; OR for death 5.39 [1.20–24.1] after adjustment for dialysis status and age). Conclusion. Combination of renal insufficiency and hyperglycemic conditions exerts a synergistic effect on vascular calcification and increases the risk of death.

Osteoprotegerin and osteoprotegerin/TRAIL ratio are associated with cardiovascular dysfunction and mortality among patients with renal failure

PURPOSE The high prevalence of cardiovascular morbidity and mortality among patients with chronic kidney disease (CKD) is observed especially in those undergoing dialysis. Osteoprotegerin (OPG) and its ligands, receptor activator of nuclear factor kappa-B ligand (RANKL) and tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) have been associated with cardiovascular complications. Our aim was to study their role as cardiovascular risk factors in stage 5 CKD patients. PATIENTS AND METHODS OPG, RANKL and TRAIL concentrations were measured in 69 hemodialyzed CKD patients and 35 healthy volunteers. In CKD patients, cardiovascular dysfunction was assessed with aortic pulse wave velocity (AoPWV), carotid artery intima-media thickness (CCA-IMT), coronary artery calcium score (CACS) and N-terminal pro-B-type natriuretic peptide (NT-proBNP) serum concentrations. Cardiovascular and overall mortality data were collected during a 7-years follow-up. RESULTS OPG plasma concentrations were higher in CKD patients comparing to controls. Total soluble RANKL was lower and OPG/RANKL ratio higher in patients. Soluble TRAIL concentrations did not differ between the groups and OPG/TRAIL ratio was higher in CKD patients. OPG and OPG/TRAIL positively predicted long-term mortality (all-cause and cardiovascular) in CKD patients. OPG positively correlated with AoPWV, CCA-IMT and NT-proBNP whereas OPG/TRAIL with AoPWV and NT-proBNP. Described relationships were independent of classical and non-classical cardiovascular risk factors, with exception of age. CONCLUSIONS Our study confirmed the role of OPG as a biomarker of cardiovascular dysfunction and a predictor of mortality in stage 5 CKD. OPG/TRAIL ratio can be proposed as a predictor of cardiovascular dysfunction and mortality.

Relationships of insulin-like growth factor-1, its binding proteins, and cardiometabolic risk in hypertensive perimenopausal women

PURPOSE During the transition from premenopause to postmenopause, many women experience weight gain and central fat deposition; therefore, we hypothesized that circulating growth factors can play a role in the pathogenesis of hypertension, metabolic syndrome, and subclinical organ damage in perimenopausal women. BASIC PROCEDURES The study included 192 women aged 40 to 60years; 152 had newly diagnosed essential hypertension that had never been treated, and 40 were normotensive age-matched controls. For all subjects, 24-h ambulatory blood pressure monitoring (ABPM), echocardiographic examination with assessment of left ventricular mass (LVM) and systolic and diastolic functions (GE Vivid 7.0, General Electric Vingmed Ultrasound, Horten, Norway), carotid ultrasound with measurement of intima-media thickness, and carotid-femoral pulse wave velocity (PWV) measurement (SphygmoCor, AtCor Medical, Sydney, Australia) were performed. Serum levels of insulin-like growth factor 1 (IGF-1), insulin-like growth factor-binding protein 2 (IGFBP-2), and insulin-like growth factor-binding protein 3 (IGFBP-3) were measured using an immunochemical assay. MAIN FINDINGS Hypertensive women had significantly lower IGFBP-2 levels than did normotensive controls (162.9±83.7 vs. 273.1±103.0μg/L, p<0.001); the groups did not differ regarding IGF and IGFBP-3 concentrations. After adjusting the covariates, multivariate analysis showed that IGFBP2 was significantly negatively correlated with 24-h systolic blood pressure (β=-0.31, p=0.02). The adjusted odds ratio for hypertension per standard deviation decrease in IGFBP-2 was 3.43 (95% confidence interval [CI] 1.65-7.13). IGFBP-2 showed a negative correlation with the number of metabolic syndrome components. Independent of body composition, IGFBP-2 was significantly related to left ventricular relative wall thickness and the ratio of mitral inflow velocities as parameter of diastolic function. PRINCIPAL CONCLUSIONS In perimenopausal women, decreased IGFBP-2 levels may play a role in blood pressure regulation and the development of subclinical left ventricular diastolic dysfunction. Whether IGFBP-2 is a marker or a mediator of cardiovascular disease in this population merits further investigation.

Carboxylated and undercarboxylated osteocalcin in metabolic complications of human obesity and prediabetes.

Carboxylated osteocalcin (Gla‐OC) participates in bone remodeling, whereas the undercarboxylated form (Glu‐OC) takes part in energy metabolism. This study was undertaken to compare the blood levels of Glu‐OC and Gla‐OC in nonobese, healthy obese, and prediabetic volunteers and correlate it with the metabolic markers of insulin resistance and early markers of inflammation.

Relation of the protein glycation, oxidation and nitration to the osteocalcin level in obese subjects

Carboxylated osteocalcin (Gla-OC) contributes to the bone formation, whereas its undercarboxylated form (Glu-OC) takes part in the energy metabolism. In vitro studies had shown that treatment of osteoblast-like cells with advanced glycation end product-modified bovine serum resulted in reduced synthesis of collagen 1 and osteocalcin. The aim of this study was to find association between Gla-OC and markers of protein glycation, oxidation and nitration, as well as pro-inflammatory and antioxidant defense markers in obese subjects. Non-obese [(body mass index (BMI)<30 kg/m; n=34)] and obese subjects (30<BMI <40 kg/m2; n=98), both sexes, aged 25 to 65 years, were included in this study. Urinary glycation, oxidation and nitration free adduct concentrations were determined by stable isotopic dilution analysis liquid chromatography and mass spectrometry, and normalized to creatinine. Obese subjects had lower Gla-OC serum levels when compared to the non-obese controls. Obese subjects had increased serum concentrations of insulin, C reactive protein, interleukin 6, leptin and insulin resistance index (HOMA IR). Urinary early glycation and advanced glycation end product (AGE) free products, Nε-fructosyl-lysine and 3-deoxyglucosone-derived hydroimidazolone, respectively, and oxidative damage marker, N-formylkynurenine free adduct, were increased in the obese compared to the non-obese subjects. Serum Gla-OC was negatively correlated with urinary methylglyoxal-derived AGE, hydroimidazolone MG-H1, and N-formylkynurenine free adducts. The Gla-OC/Glu-OC index negatively correlated with the MG-H1 free adduct, and correlated positively with the antioxidant defense marker - the glutathione peroxidase activity. Our results suggest that increased AGEs and protein oxidative damage markers in the course of obesity may contribute to decreased Gla-OC level and, consequently, future risk of decreased bone formation.

Serum uromodulin concentrations correlate with glomerular filtration rate in patients with chronic kidney disease

INTRODUCTION Urinary uromodulin excretion has been associated with kidney diseases. However, serum uromodulin concentrations have not been extensively studied in patients with chronic kidney disease (CKD), and the results of published studies are inconsistent. OBJECTIVES The aims of the study were to evaluate serum uromodulin concentrations in patients with CKD and to assess the utility of serum uromodulin measurements for diagnosing CKD stages. PATIENTS AND METHODS This observational study included 170 patients with CKD stages 1 to 5, not treated by renal replacement therapy, and 30 healthy individuals. The serum levels of creatinine, cystatin C, and uromodulin were measured, and estimated glomerular filtration rate (eGFR) was calculated according to the 2012 CKD Epidemiology Collaboration cystatin‑creatinine equation. RESULTS Among patients with CKD, serum uromodulin concentrations were significantly lower than in controls, and were strongly negatively correlated with renal retention markers (ie, serum creatinine and cystatin C) and strongly positively correlated with eGFR. An inverse, hyperbolic relationship between serum creatinine and uromodulin levels was analogous to the well‑known association between serum creatinine concentrations and eGFR. A receiver‑operating characteristic curve analysis showed a high diagnostic accuracy of the measurement of serum uromodulin concentrations in the assessment of CKD stages. CONCLUSIONS Serum uromodulin concentrations are closely correlated with eGFR, which is the recommended measure of renal function. As uromodulin is produced exclusively by renal tubular cells, the assessment of uromodulin levels in patients with CKD may be an alternative method for evaluating the number of functioning nephrons.