The Impact of Osteocalcin, Osteoprotegerin and Osteopontin on Arterial Stiffness in Chronic Renal Failure Patients on Hemodialysis.

BACKGROUND/AIMS: This cross-sectional study was designed to assess the relationship between vascular stiffness (VS) and bone-related proteins involved in the development of arteriosclerosis in patients on regular hemodialysis (HD). METHODS: 68 consecutive patients in stable clinical condition who received regular HD in the FMC Dialysis Center, Pécs were included. VS parameters (carotid-femoral pulse wave velocity - PWV, aortic augmentation index - AIx) were determined by applanation tonometry (SphygmoCor, AtCor Medical, Sidney) and the routine latoratory test were completed with measurements of osteocalcin (OC), osteopontin (OP) and osteoprotegerin (OPG) by using commercially available ELISA kits. 35 heathcare workers served as controls. RESULTS: In patients on regular HD PWV markedly increased and there was several-fold elevation in the interrelated bone-specific proteins (OC, OP, OPG). PWV was found to be independently associated only with OC (ß:-0.25, p<0.029) and age (r=0.411,p<0.000), but risk factors for arterial calcification had significant impact on OC (systolic blood pressure, hsCRP, BMI), OPG (age, BMI) and OP (LDL-cholesterol). CONCLUSION: Except for OC, our results failed to document direct association of vascular lesion with OP and OPG, therefore their high circulating levels may be an epiphenomenon or they may have counter-regulatory role to attenuate the uremic calcification process.

Serum and follicular fluid fetuin-A in women undergoing in vitro fertilization.

BACKGROUNDS: This case-control study was designed to assess the possible role of fetuin-A, a multifunctional protein, in reproductive processes of women undergoing in vitro fertilization (IVF). METHODS: Paired serum and follicular fluid (FF) samples were obtained from 35 unselected patients who received IVF treatment. Their main clinical chartacteristics: age 35.2±5.4 years, BMI 22.9±2.8, duration of infertility 3.2±2.0 years, gonadotropin administered 1199.4±202.3 IU, and estradiol level on day 6 of stimulation 1827±1342 pmol/L. In total 25 healthy women of similar age admitted for minor elective surgery served as controls for serum analysis. Fetuin-A and high-sensitivity C-reactive protein (hsCRP) were measured in serum and FF by using commercially available ELISA kits and turbidimetric immunoassay, respectively. RESULTS: Serum fetuin-A levels of patients participating IVF are markedly elevated when compared to those of healthy women (1.30±0.58 g/L vs. 0.55±0.09 g/L, p<0.000). Fetuin-A in FF proved to be comparable to its serum levels (1.17±0.45 g/L) and no relationship could be detected between the respective individual values. Moreover, markers of reproductive potential (number of oocytes and embryos) appeared to be independent of serum and FF fetuin-A. hsCRP in serum and FF was not related to fetuin-A and did not influence the number of oocytes and embryos. CONCLUSIONS: Fetuin-A concentration is high in FF of patients undergoing IVF, however, it can not be used as an estimate of fertilization success.

Effect of Oxidative Stress in Hemodialysed Patients.

AIMS SUBJECTS AND METHODS: Markers of oxidative stress and inflammatory activation of endothelium, as well as the adipose tissue secreted adipokines, e.g. adiponectin show altered pattern in renal failure. However, their internal relations have not been fully evaluated in this special patient population. In our cross sectional study, beside the routine clinical and biochemical parameters, plasma malondialdehyde, glutathione (GSH), catalase, total peroxidase, as well as serum E-selectin and adiponectin were measured in 70 hemodialysed (HD) patients. RESULTS: GSH showed negative correlations with systolic and diastolic blood pressure (BP) values, while a positive one with HDL-cholesterol level, as expected. Interestingly, the level of sE-selectin was inversely correlated only with the age. In multiple regression analyses where anthropometric, BP and laboratory parameters were included and sE-selectin was the dependent variable, the inverse association between the age and level of sE-Selectin turned out being an independent factor. CONCLUSIONS: In HD kidney failure patients of the biochemical cardiovascular risk markers those related to oxidative stress, endothelial dysfunction, or altered adipokine homeostasis are not necessarily strongly associated. Larger studies may be needed to confirm our novel observation, a negative and independent correlation of age to sE-Selectin level.

Associations of adiponectin with paraoxonase 1 and sE-selectin in hemodialyzed patients.

BACKGROUND/AIMS: In hemodialyzed (HD) patients, adiponectin and sE-selectin levels are elevated, while antioxidant paraoxonase 1 activity (PON1) is decreased. We determined if the hyperadiponectinemia in HD patients has a protective effect on the decrease in PON1 and elevation in sE-selectin in kidney failure. METHODS AND DESIGN: Predialysis serum adiponectin, PON1 and sE-selectin as well as other metabolic variables were measured in 70 HD patients. RESULTS: Adiponectin had (1) no association with PON1 or sE-selectin, (2) a positive association with dialysis efficiency and HDL-C, and (3) an inverse association with BMI, waist circumference, HOMA IR, triglyceride, hsCRP, fibrinogen, and albumin. Moreover, albumin, BMI, and HOMA-IR were independent negative predictors of adiponectin. CONCLUSIONS: In kidney failure, in contrast to normal renal function, higher adiponectin levels had no correlation with PON1 activity or the sE-selectin level. However, adiponectin has an association with dialysis efficiency and, similar to individuals with preserved kidney function, traits of metabolic syndrome. In addition to BMI and HOMA-IR, the serum albumin concentration is also one of the independent negative predictors of the serum adiponectin level. Collectively, these findings may add details to the understanding of the role that adiponectin plays in chronic renal disease related to 'reverse epidemiology'.

Naturally occurring and disease-associated auto-antibodies against topoisomerase I: a fine epitope mapping study in systemic sclerosis and systemic lupus erythematosus.

Auto-antibodies against topoisomerase I (topo I) are frequently detected in sera of systemic sclerosis (SSc) patients. Anti-topo I auto-antibodies are considered to be associated with the diffuse cutaneous form of systemic sclerosis (dcSSc). However, anti-topo I auto-antibodies are also detected in limited cutaneous systemic sclerosis (lcSSc) and systemic lupus erythematosus (SLE). In this study, we compared the epitope specificity of anti-topo I auto-antibodies present in sera of dcSSc, lcSSc and SLE patients. We have constructed an antigen fragment library displayed on bacteriophage lambda and screened this library with IgG purified from patients' sera. Regions of topo I selected from the library were expressed as recombinant fusion proteins and were tested with ELISA and western blot. We unexpectedly found that antibodies against a fragment of topo I [fragment F4 [amino acid (AA)] 451-593] could be detected in sera of healthy individuals and patients with inflammatory rheumatic diseases other than SSc and SLE. Using sera of dcSSc, lcSSc and SLE patients, we showed that the pattern of recognized epitopes is different between these patient groups. Fragment F4 was recognized by all patients. Fragment F1 (AA 5-30) was recognized by 9 of 34 dcSSc patients. Fragment F8 (AA 350-400) was recognized by four of eight SLE patients. Analysis of clinical data revealed a significant difference between the F1-negative and F1-positive groups of SSc patients in age and in the duration of the disease. According to our results, the newly identified fragments F1 and F8 could represent characteristic epitopes for dcSSc and SLE, respectively.

Relationship of adiponectin to serum paraoxonase 1.

UNLABELLED: Correlation of the plasma levels of insulin-sensitizing, anti-inflammatory and anti-atherosclerotic adiponectin with HDL has been demonstrated. However, its relation to HDL-bound paraoxonase 1 (PON1) has not been clarified. The association of serum PON1 activity with findings of metabolic syndrome was investigated in three age and sex-matched groups: (1) non-diabetic overweight subjects with BMI 28-39.9 kg/m(2) (n=25); (2) non-diabetic obese subjects with BMI>or=40 kg/m(2) (n=25); and (3) healthy, normal-weight controls (n=24). Of the parameters investigated, PON1 activity correlated positively with concentrations of HDL-C and adiponectin, and correlated negatively with BMI, waist circumference, systolic BP, levels of HbA(1C), and insulin, HOMA-IR, and TBARS. The positive correlation between adiponectin and PON1 remained significant even after adjustments for age, gender, BMI, blood pressure, HOMA-IR, HDL-C, LDL-C, and lipid peroxidation. CONCLUSIONS: PON1 activity shows negative association with markers of metabolic syndrome. We demonstrate that adiponectin is an independent variable of serum PON1, which may contribute to the anti-atherosclerotic effect of adiponectin.

Relationship of endogenous hyperleptinemia to serum paraoxonase 1, cholesteryl ester transfer protein, and lecithin cholesterol acyltransferase in obese individuals.

Altered activities of high-density lipoprotein (HDL)-associated antioxidant enzyme paraoxonase 1 (PON1) and lipid transfer proteins, for example, cholesteryl ester transfer protein (CETP) and lecithin cholesterol acyltransferase (LCAT), participating in lipoprotein remodeling seem to play important roles in obesity-related accelerated atherosclerosis. Inverse associations of PON1 with obesity and serum leptin levels have been demonstrated. However, the relationship of leptin with CETP and LCAT in humans is less clear. Our aims were to investigate whether the elevated leptin level is (a) an independent predictor of low PON1 and (b) associated with alterations of CETP and LCAT activities. Seventy-four white subjects forming 3 age- and sex-matched groups were included into the study (groups 1 and 2: nondiabetic obese patients, n = 25 with body mass index [BMI] 28-39.9 kg/m2 and n = 25 with BMI >or=40 kg/m2, respectively; and group 3: 24 healthy, normal-weight control subjects). Paraoxonase 1 correlated inversely with BMI (r = -0.39, P < .01), waist circumferences (r = -0.42, P < .001), and leptin concentrations (r = -0.38, P < .001). However, in a multiple regression model, neither these variables nor others, for example, age, sex, blood pressure, insulin resistance (in homeostasis model assessment of insulin resistance [HOMA-IR]), HDL cholesterol, low-density lipoprotein cholesterol, or lipid peroxidation (measured as thiobarbituric acid reactive substances), proved to be independent predictors of PON1. Lecithin cholesterol acyltransferase correlated negatively with BMI (r = -0.40, P < .01), waist circumferences (r = -0.42, P < .001), and leptin levels (r = -0.40, P < .01). During multiple regression analyses, BMI was an independent predictor of LCAT after adjustments for age, sex, HOMA-IR, and HDL cholesterol. However, this was replaced by leptin and HOMA-IR when leptin was also included into the model. The CETP activities correlated with HOMA-IR (r = 0.33, P < .01), thiobarbituric acid reactive substances (r = 0.45, P < .001), and leptin (r = 0.36, P < .01) levels in univariate but not in multivariate models. Elevated leptin level is an independent predictor of low LCAT, but not PON1, activity. In a population with a wide range of BMI, LCAT correlates inversely with obesity and CETP directly with insulin resistance.