Osteoprotegerin in Chronic Kidney Disease: Associations with Vascular Damage and Cardiovascular Events.

Vascular injury and dysfunction contribute to cardiovascular disease, the leading cause of death in patients with chronic kidney disease (CKD). Osteoprotegerin (OPG) is a soluble member of the tumor necrosis factor receptor superfamily that has been linked to atherogenesis and endothelial dysfunction. Elevated circulating OPG levels predict future cardiovascular events (CVE). Our aim was to evaluate the determinants of circulating OPG levels, to investigate the relationship between OPG and markers of vascular damage and to test whether OPG improves risk stratification for future CVE beyond traditional and renal-specific risk factors in a CKD population. 291 patients with CKD stage 1-5 not on dialysis were included in the study. In the multivariate analysis, OPG was a significant predictor for flow-mediated dilatation, but not for carotid intima media thickness levels. During follow-up (median 36 months, IQR = 32-42 months), 87 patients had CVE. In the Cox survival analysis, OPG levels were independently associated with CVE even after adjustment for traditional and renal-specific cardiovascular risk factors. The addition of OPG to a model based on commonly used cardiovascular factors significantly improved the reclassification abilities of the model for predicting CVE. We show for the first time that OPG improves risk stratification for CVE in a non-dialysis CKD population, above and beyond a model with established traditional and renal-specific cardiovascular risk factors, including estimated glomerular filtration rate and fibroblast growth factor 23.

Ultrasonographic evaluation of the femoral cartilage thickness in patients with chronic renal failure.

OBJECTIVE: To investigate the effects of chronic renal failure (CRF) on the distal femoral cartilage thickness by using ultrasonography and to determine the relationship between cartilage thickness and certain disease-related parameters. DESIGN: Fifty-seven CRF patients (41 male and 16 female) (mean [SD] age, 44.7 [12.1] years) and 60 healthy controls (41 male and 19 female) (mean [SD] age, 43.5 [13.3] years) were enrolled in this study. Demographic and clinical characteristics were recorded. Cartilage thickness measurements were taken from the medial and lateral condyles, and intercondylar areas of both knees. RESULTS: Groups were similar in terms of age, weight, height, body mass index and gender (all p>0.05). The mean cartilage thickness was found to be less in CRF patients than in controls (statistically significant for medial condyles and intercondylar areas both in right and the left knees [all p<0.05]). Cartilage thickness showed no correlation with eGFR, and with the levels of serum urea, creatinine, calcium, magnesium, phosphor, hemoglobin, uric acid and as well as steroid use (all p>0.05) in CRF patients. CONCLUSION: In the light of our findings, we imply that patients with CRF have thinner femoral cartilage than healthy controls. This result may support the view that patients with CRF are at increased risk for developing early knee osteoarthritis. Last but not least, clinicians should be aware of the importance of rehabilitation strategies aimed at decreasing onset and progression of knee osteoarthritis in patients with CRF.

The role of plasma triglyceride/high-density lipoprotein cholesterol ratio to predict cardiovascular outcomes in chronic kidney disease.

BACKGROUND: Cardiovascular disease (CVD) risk is substantially increased in subjects with chronic kidney disease (CKD). The Triglycerides (TG) to High-Density Lipoprotein Cholesterol (HDL-C) ratio is an indirect measure of insulin resistance and an independent predictor of cardiovascular risk. No study to date has been performed to evaluate whether the TG/HDL-C ratio predicts CVD risk in patients with CKD. METHODS: A total of 197 patients (age 53±12 years) with CKD Stages 1 to 5, were enrolled in this longitudinal, observational, retrospective study. TG/HDL-C ratio, HOMA-IR indexes, serum asymmetric dimethyl arginine (ADMA), high sensitivity C-reactive protein (CRP), parathyroid hormone (PTH), calcium, phosphorous, estimated glomerular filtration rate (eGFR), and albumin levels were measured. Flow mediated vasodilatation (FMD) of the brachial artery was assessed by using high-resolution ultrasonography. RESULTS: A total of 11 cardiovascular (CV) deaths and 43 nonfatal CV events were registered in a mean follow-up period of 30 (range 9 to 35) months. Subjects with TG/HDL-C ratios above the median values (>3.29) had significantly higher plasma ADMA, PTH, and phosphorous levels (p=0.04, p=0.02, p=0.01 respectively) and lower eGFR and FMD values (p=0.03, p<0.001 respectively). The TG/HDL-C ratio was an independent determinant of FMD (ß=-0.25 p=0.02) along with TG, HDL-C, hsCRP, serum albumin, phosphate levels, systolic blood pressure, PTH, eGFR and the presence of diabetes mellitus. The TG/HDL-C ratio was also a significant independent determinant of cardiovascular outcomes [HR: 1.36 (1.11-1.67) (p=0.003)] along with plasma ADMA levels [HR: 1.31 (1.13-1.52) (p<0.001)] and a history of diabetes mellitus [HR: 4.82 (2.80-8.37) (p<0.001)]. CONCLUSION: This study demonstrates that the elevated TG/HDL-C ratio predicts poor CVD outcome in subjects with CKD. Being a simple, inexpensive, and reproducible marker of CVD risk, the TG/HDL-C ratio may emerge as a novel and reliable indicator among the many well-established markers of CVD risk in CKD. SYSTEMATIC REVIEW REGISTRATION: Clinical trial registration number and date: NCT02113462 / 10-04-2014.

Ramipril lowers plasma FGF-23 in patients with diabetic nephropathy.

BACKGROUND/AIMS: Ramipril attenuates renal Fibroblast growth factor-23 (FGF-23) expression, ameliorates proteinuria and normalizes serum phosphate in the diabetic Zucker rat with progressive renal disease suggesting that the renoprotective effect by this drug may be in part due to a FGF-23-lowering effect of angiotensin-converting enzyme (ACE) inhibition. METHODS: In this nonrandomized study, we tested whether ACE-inhibition reduces circulating FGF-23 in type-2 diabetics with stage-1 chronic kidney disease (CKD) and proteinuria. Intact FGF-23, the eGFR, proteinuria and the endothelium-dependent flow-mediated (FMD) response to ischemia and other parameters were measured at baseline and after 12-weeks of treatment with ramipril (n = 68) or amlodipine (n = 32). RESULTS: Blood Pressure (BP) fell to a similar extent (p < 0.001) in the two groups. However, 24 h proteinuria and the FMD improved more (both p < 0.01) in ramipril-treated patients than in amlodipine-treated patients. Changes in proteinuria (r = 0.47) and in FMD (r = -0.49) by ramipril were closely associated (p < 0.001) with simultaneous changes in FGF-23 and this link was confirmed in multiple regression analyses. In these analyses, the relationship between FMD and proteinuria changes attained statistical significance (p < 0.01) only in a model excluding FGF-23 suggesting that endothelial dysfunction and FGF-23 share a common pathway conducive to renal damage. CONCLUSION: Findings in this study contribute to generate the hypothesis that FGF-23 may be implicated in proteinuria and in endothelial dysfunction in diabetic nephropathy (clinicaltrials.gov (NCT01738945)).

Mitral annular calcification and the serum osteocalcin level in patients with chronic kidney disease.

OBJECTIVE: To determine the relationships between inflammatory mediators, mitral annular calcification (MAC), and osteocalcin in patients with chronic kidney disease (CKD). MATERIALS AND METHODS: Echocardiographic data for 60 patients diagnosed as CKD were retrospectively evaluated. The patients were divided into 2 groups; patients with MAC (MAC+ group) and patients without MAC (MAC- group). The relationships between biochemical markers-including osteocalcin-and MAC were evaluated. RESULTS: The study included 19 female and 41 male patients. In all, 29 patients were MAC+ and 31 were MAC-. High-sensitive C-reactive protein (hsCRP) and osteocalcin levels were significantly higher in the MAC+ group (p < 0.05). The eGFR was lower, serum calcitonin (we could not obtain calcitonin data for 15 patients), Ca, PO4, CaxPO4, the erythrocyte sedimentation rate, red cell distribution width, the neutrophil/Lymphocyte rate, and PTH were higher in the MAC+ group; however, the differences between the groups were not significant (p > 0.05). The mitral E/A ratio, mitral peak Ea velocity, tricuspid E/A ratio, hsCRP, and the osteocalcin level were strongly correlated with MAC. Multivariate logistic regression analysis showed that only the osteocalcin level and mitral E/A ratio were independent variables, each with an independent effect on MAC. CONCLUSION: CKD patients in the MAC+ group had higher osteocalcin levels than those in the MAC- group, and left ventricular diastolic dysfunction was more common in the MAC+ group.

Soluble TWEAK plasma levels increase after renal transplantation and associate with the improvement of endothelial function.

BACKGROUND: Soluble TWEAK (sTWEAK) and asymmetric dimethyl arginine (ADMA) concentrations have been associated with endothelial function in patients with chronic kidney disease (CKD). We tested the hypothesis that the improvement in endothelial function observed after renal transplantation is directly linked to the normalization of both sTWEAK and ADMA. MATERIALS AND METHODS: One hundred and seventy-five kidney transplant recipients (71% men; 31·6 ± 9·4 years) were studied immediately before and on the 180th day post-transplantation. At each visit, blood samples were taken to assess circulating levels of sTWEAK and ADMA. Brachial artery endothelium-dependent vasodilatation (FMD) assessments were also performed. RESULTS: Renal transplantation was followed by an improvement in FMD. This improvement was paralleled by an increase in sTWEAK and a reduction in ADMA after transplantation (P < 0·001 for all). Cross-sectionally, both molecules associated with FMD before as well as after transplantation (P < 0·001 for all). Longitudinally, the changes observed in sTWEAK (ß = 0·26, P < 0·001) and ADMA (ß = -0·44, P < 0·001) levels were independently associated with the improvement of FMD (r(2)  = 0·30). CONCLUSIONS: Renal transplantation is followed by an improvement of FMD that is independently associated with the normalization of both sTWEAK and ADMA concentrations. We identify two surrogate biomarkers of endothelial function with potential as therapeutic targets.

Longitudinal analysis of vascular function and biomarkers of metabolic bone disorders before and after renal transplantation.

BACKGROUND/AIMS: The role of chronic kidney disease-mineral bone disorder (CKD-MBD) reversibility in the amelioration of vascular function and in the reduction of the risk for cardiovascular events after renal transplantation is still unknown. METHODS: We investigated the longitudinal relationship between the main biomarkers of CKD-MBD and the evolution of vascular function [flow-mediated dilatation (FMD)] after transplantation in a series of 161 patients with kidney failure maintained on chronic dialysis (5D-CKD). RESULTS: Before transplantation, FMD in patients was markedly lower (-40%, p < 0.001) than in well-matched healthy subjects and increased by 27% after transplantation (p = 0.001). Fibroblast growth factor 23 (FGF23), 25-hydroxy-vitamin D (25OHVD) and serum phosphate (p < 0.01) were independently associated with simultaneous changes in FMD. Changes in classical risk factors and in risk factors related to CKD like the glomerular filtration rate, serum albumin, C-reactive protein and insulin resistance failed to independently explain the variability in FMD changes after transplantation. CONCLUSION: Endothelium-dependent vasodilatation improves after kidney transplantation, which is parallel to the dramatic fall in FGF23, the reduction in serum phosphorus and the increase in 25OHVD levels. If these associations are causal, a part of decline in cardiovascular risk after transplantation is related to partial resolution of CKD-MBD.

Neutrophil to lymphocyte ratio independently predicts cardiovascular events in patients with chronic kidney disease.

BACKGROUND: Increased inflammation is common in patients with chronic kidney disease (CKD) and is associated with increased adverse cardiovascular events (CVE). Neutrophil-to-lymphocyte ratio (NLR) was used to predict survival in patients with acute coronary syndrome. We aimed to evaluate predictive ability of NLR in CKD patients. METHODS: 225 subjects with stage 3-5 CKD were followed for a mean of 39 months. Fatal and nonfatal CVE were recorded during this period. NLR at baseline was determined from complete blood count differential. Endothelial dysfunction (flow-mediated dilation, FMD), hsCRP and insulin resistance were determined. We investigated if NLR could predict development of fatal and nonfatal CVE. We also looked at how NLR and its individual components change across CKD stages and whether NLR is related to CRP, insulin resistance and endothelial dysfunction. RESULTS: There were 70, 74 and 81 patients in groups of CKD stage-3, stage-4 and stage-5, respectively. Median NLR was 2.81. NLR showed a significant increase from stage 3 to stage 5. NLR was inversely associated with FMD independent of hsCRP. 14 fatal and 52 nonfatal CVE occurred during follow-up period. NLR could predict composite CVE independent of insulin resistance and hsCRP. Increased NLR over 2.81 was related to a significantly decreased survival time (log-rank Chi-square = 14.833, P < 0.0001). A cutoff value for NLR ≥3.76 could predict development of composite CVE with 80.3 % sensitivity and 91.8 % specificity. CONCLUSIONS: NLR is independently related to endothelial dysfunction and could predict composite cardiovascular endpoints independent of traditional confounding factors in patients with moderate to severe CKD.

Mean corpuscular volume is associated with endothelial dysfunction and predicts composite cardiovascular events in patients with chronic kidney disease.

AIM: Mean corpuscular volume (MCV) is a measure of size of red blood cells. Recently a few studies showed an association of macrocytosis with all-cause mortality. We aimed to assess the relationship of MCV with cardiovascular (CV) morbidity and mortality in patients with chronic kidney disease (CKD), and the effect of MCV on endothelial function. METHODS: This is an observational cohort study with a prospectively maintained cohort of patients with stage 1-5 CKD. Estimated glomerular filtration rate (eGFR), flow mediated dilatation (FMD) and laboratory values were measured at baseline. Multivariate linear and Cox regression analyses were used to predict independent associations of FMD and composite CV events, respectively. RESULTS: A total of 309 patients were included in the study. In contrast to anaemia MCV did not show a significant change among CKD groups. MCV was an independent predictor of FMD in addition to serum haemoglobin, CRP, diabetes, systolic blood pressure (SBP) and eGFR. Median MCV value was 85 fl. Kaplan-Meier analysis showed that at 38 months the survival rate was 97.6% in the group with MCV < 85 compared to 81.6% in the arm with MCV ≥ 85 (P < 0.001, log-rank test). Cox regression analysis showed MCV as a predictor of composite CV events independent of major confounding factors. CONCLUSION: This is the first study in the literature showing an independent association of MCV and FMD. Our results also determined MCV as an independent predictor of composite CV events independent of anaemia, inflammation, diabetes and eGFR in patients with CKD.

Relationship between serum magnesium levels and cardiovascular events in chronic kidney disease patients.

BACKGROUND: Magnesium is an essential ion for all living cells because over 300 enzymes require the presence of magnesium for their catalytic action. To date, no group has evaluated magnesium as a cardiovascular risk factor in chronic kidney disease (CKD) subjects, in which closely interrelated factors and potential confounders such as endothelial dysfunction, insulin resistance (the homeostasis model assessment (HOMA) index) and inflammation (expressed as serum C-reactive protein (CRP) levels) were also considered. METHODS: Between March 2006 and December 2010, 283 CKD patients were followed up for time-to-event analysis until the occurrence of fatal or nonfatal cardiovascular events. Endothelium-dependent vasodilatation (flow-mediated dilatation; FMD) and endothelium-independent vasodilatation (nitroglycerin-mediated dilatation) of the brachial artery were assessed noninvasively using high-resolution ultrasound. RESULTS: From the univariate analysis of FMD, it appears that a higher magnesium level is associated with less endothelial dysfunction. When a multivariate analysis was performed, magnesium and estimated glomerular filtration rates (eGFR) maintained a strong positive correlation with FMD, supporting the hypothesis that higher levels of magnesium may protect against endothelial damage. In univariate Cox proportional hazards models, FMD, magnesium, high sensitivity CRP, the HOMA index, eGFR, comorbid diabetes, hypertension, smoking status, systolic blood pressure, serum phosphate and intact parathormone emerged as significant predictors for cardiovascular outcomes. Kaplan-Meier curves showed significantly higher cardiovascular mortality rates in CKD patients whose serum magnesium levels were below 2.05 mg/dl. CONCLUSIONS: This observational cohort study showed that magnesium may be an independent predictor of future cardiovascular outcomes and is the first study demonstrating such a role in etiologically diagnosed CKD patients, across different stages.

Serum uric acid independently predicts cardiovascular events in advanced nephropathy.

BACKGROUND: Chronic kidney disease (CKD) is associated with increased risk for cardiovascular (CV) disease and is also associated with elevated uric acid, which is emerging as a nontraditional CV risk factor. We therefore evaluated uric acid as a risk factor for CV disease in subjects presenting to nephrologists with CKD who were not on medications known to alter endothelial function. METHODS: 303 subjects with stage 3-5 CKD were followed for a mean of 39 months (range 6-46) and assessed for fatal and nonfatal CV events. Hyperuricemia was defined as uric acid >6.0 mg/dl for women and >7.0 mg/dl for men. In addition to other CV risk factors, endothelial function (flow-mediated dilatation), inflammatory markers (hsCRP), and insulin resistance (HOMA index and fasting insulin levels) were included in the analysis. We evaluated the association between uric acid and flow-mediated dilatation with linear regression. The impact of uric acid on composite CV events was assessed with Cox regression analysis. RESULTS: Of a total of 303 patients, 89 had normouricemia and 214 had hyperuricemia. Both fatal (32 of 214 vs. 1 of 89 subjects) and combined fatal and nonfatal (100 of 214 vs. 13 of 89 subjects) CV events were more common in subjects with hyperuricemia compared with normal uric acid levels, and this was independent of estimated glomerular filtration rate, traditional CV risk factors including diabetes, hypertension and BMI, and nontraditional risk factors (hsCRP and endothelial function). The 46-month survival rate was 98.7% in the group with low uric acid compared to 85.8% in patients with high uric acid (p = 0.002). CONCLUSIONS: Hyperuricemia is an independent risk factor for CV events in subjects presenting with CKD who are not on medications known to alter endothelial function.

Findings of biopsy-proven chronicity and end-stage renal failure associated with oral sodium phosphate solution.

Bowel purgatives containing oral sodium phosphate (OSP) solution are used frequently in general practice and they have the potential of causing acute kidney injury especially in patients with some identified risk factors. Kidney injury may lead to chronicity and end-stage renal disease. Here we present, with renal biopsy findings, an elderly patient suffering from end-stage renal failure due to OSP solution.

Chitotriosidase as a novel biomarker of early atherosclerosis in hemodialysis patients.

INTRODUCTION: Increasing evidence suggests that inflammation and increased macrophage activity have a central role in pathogenesis of atherosclerosis. It is shown that chitotriosidase (CHIT-1) is a marker of macrophage activity in atherosclerotic plaque, and is found associated with severity of atherosclerotic lesion. There is no data about CHIT-1 activity of hemodialysis patients in the literature. Thus, we hypothesized that in hemodialysis patients, CHIT-1 levels might be a novel biomarker in early atherosclerosis. METHODS: Forty-five hemodialysis patients were included in the study (age: 61.93 ± 13.34). Intima media thickness (IMT) was evaluated with high-resolution B-mode ultrasonography. Biomarker levels were measured in serum of patients. FINDINGS: We found positive correlation among IMT, age (R: 0.426, P: 0.004) and, CHIT-1 value (R: 0.462, P: 0.001) in spearman correlation analysis. When age, CRP, creatinine, P, Alb, CHIT-1 were chosen as measures that can effect IMT in multiple regression model, IMT level was related with CHIT-1 (Beta: 0,396, P: 0.012) and age (Beta: 0,313 P: 0,048) independently. DISCUSSION: In conclusion, this is the first report showing that serum CHIT-1 level was related independently with carotid IMT in hemodialysis patients. This biomarker might have an unknown role in the development of atherosclerosis during uremia.

IL-33 and ST2 levels in chronic kidney disease: Associations with inflammation, vascular abnormalities, cardiovascular events, and survival.

OBJECTIVE: Increased inflammation, associated with the increase in chronic kidney disease (CKD) stage, has a very important influence in vascular injury and cardiovascular diseases. In this study, we aimed to investigate the levels of IL-33 and ST2 in the different stages of CKD and to determine their effect on vascular damage and cardiovascular events (CVE). METHODS: This was an observational cohort study in which serum IL-33 and ST2 were obtained from 238 CKD (stages 1-5) patients. We examined the changes in IL-33/ST2 levels in CKD patients, as well as the association with a surrogate of endothelial dysfunction. Fatal and non-fatal CVE were recorded for a mean of 24 months. We also performed a COX regression analysis to determine the association of IL-33/ST2 levels with CVE and survival. RESULTS: IL-33 and ST2 levels were significantly increased and estimated glomerular filtration rates (eGFR) were decreased. Flow-mediated dilatation (FMD) was significantly decreased from stage 1 to stage 5 CKD. IL-33 and ST2 levels were associated with FMD, and ST2 was a predictor. Multivariate Cox analysis showed that the presence of diabetes mellitus, smoking, and proteinuria and haemoglobin, Hs-CRP, IL-33, and ST2 were associated with the risk of CVE. Kaplan-Meier survival curves showed that patients with IL-33 and ST2 levels below the median value (IL-33 = 132.6 ng/L, ST2 = 382.9 pg/mL) had a higher cumulative survival compared with patients who had IL-33 and ST2 levels above the median value (log-rank test, p = 0.000). CONCLUSION: This is the first study that demonstrates that serum IL-33 and ST2 are associated with vascular injury, cardiovascular events, and survival in CKD patients.

The Relationship Between Plasma Whole Blood Viscosity and Cardiovascular Events in Patients With Chronic Kidney Disease.

BACKGROUND: Plasma levels of estimated whole blood viscosity (eWBV) have been increased by endothelial inflammation. Because there were no consistent data for assessing the eWBV levels for prediction of cardiovascular event (CVE) in patients with chronic kidney disease (CKD). We aimed to investigate the relationship between plasma eWBV levels and CVEs in patients with CKD. MATERIALS AND METHODS: We conducted a prospective, cross-sectional, long-term follow-up study, assessing the relationship between plasma eWBV levels and CVE (either fatal or nonfatal) in patients with newly diagnosed CKD. We also evaluated estimated glomerular filtration rate (eGFR), pentraxin 3 (PTX3), high-sensitivity C-reactive protein (hsCRP), and flow-mediated dilatation (FMD). RESULTS: Study patients were divided into 2 groups: patients with CVE and patients without CVE. The eWBV levels were higher in patients with CVE. Additionally, PTX3 and hsCRP were higher, and FMD and eGFR were lower in patients with CVE compared to those without CVE. According to the Cox regression analysis, WBV, plasma asymmetric dimethylarginine levels, FMD, hsCRP, eGFR, systolic blood pressure, calcium, and history of diabetes were independent predictors of CVEs in patients with CKD. Kaplan Meier survival curves were generated to establish the impact of the WBV on the cumulative survival of the cohort. Patients with eWBV values higher than 5.2 centipoise (cP) had lower survival rates when compared to patients with eWBV values lower than 5.2 cP (log rank = 4.49 df = 1 P = .034). CONCLUSION: In conclusion, plasma eWBV levels may increase the presence of lower eGFR and affect CVE in patients with CKD independent of classical and unconventional risk factors.

Thyroid function and cardiovascular events in chronic kidney disease patients.

BACKGROUND AND AIMS: Abnormalities of thyroid function are commonly seen in chronic kidney disease (CKD) patients. They are associated with adverse clinical conditions such as atherosclerosis, endothelial dysfunction, inflammation and abnormal blood pressure variability. We investigated the association between thyroid disorders and endothelial function, assessed by flow-mediated dilatation (FMD) and carotid intima-media thickness (CIMT), and cardiovascular events (CVE) in CKD patients. MATERIALS AND METHODS: This observational cohort study included 305 CKD (stages 1-5) patients. Routine biochemistry, including free T3, free T4 and thyroid stimulating hormone, fibroblast growth factor-23 (FGF-23) and FMD, CIMT were measured. We divided patients into four groups according to thyroid hormone status: euthyroidism, subclinical hyperthyroidism, subclinical hypothyroidism, and euthyroid sick syndrome. Fatal and composite CVE were recorded for a median 29 months. RESULTS: Patients with subclinical hypothyroidism had a higher prevalence of hypertension and diabetes and also were more likely to have higher values of systolic CIMT, phosphorus, intact parathormone (iPTH), FGF-23, homeostasis model assessment-insulin resistance and lower levels of FMD than euthyroid patients. In the unadjusted survival analysis, subclinical hypothyroidism and euthyroid sick syndrome were associated with an increased risk for the outcome as compared with euthyroidism [hazard ratio 30.63 (95 % confidence interval 12.27-76.48) and 12.17 (3.70-39.98), respectively]. The effects of subclinical hypothyroidism and euthyroid sick syndrome were maintained even in fully adjusted models. CONCLUSION: We demonstrated that subclinical hypothyroidism and euthyroid sick syndrome are associated with increased CVE in CKD patients. Further studies are needed to explore these issues.

Endostatin in chronic kidney disease: Associations with inflammation, vascular abnormalities, cardiovascular events and survival.

BACKGROUND AND AIMS: Endostatin, generated from collagen XVIII, and endorepellin, possess dual activity as modifiers of both angiogenesis and endothelial cell autophagy. Plasma endostatin levels are elevated in a large number of diseases, and may reflect endothelial cell dysfunction. Few data on endostatins are available for patients with chronic kidney disease (CKD). We tested whether serum endostatin values are predictive for all-cause mortality and cardiovascular events (CVEs) in a CKD population. MATERIALS AND METHOD: A total of 519 CKD pre-dialysis patients were included. Baseline plasma endostatin levels were measured in all patients. All included patients were followed-up (time-to-event analysis) until occurrence of death, fatal or nonfatal CVEs. Fatal and nonfatal CVE including death, stroke, and myocardial infarction were recorded prospectively RESULTS: The mean age of the patients was 52.2±12.3years. There were 241 (46.4%) males, 111 (21.4%) had diabetes, 229 (44.1%) were smokers and 103 (19.8%) had a previous CVE. After a median follow-up of 46months, 46 patients died and 172 had a new CVE. In the univariable Cox survival analysis, higher endostatin levels were associated with a higher risk for both outcomes. However, after adjusting for traditional (age, gender, smoking status, diabetes, systolic blood pressure, HDL and total cholesterol) and renal-specific (eGFR, proteinuria and hsCRP) risk factors, endostatin levels remained associated only with the CVE outcome (HR=1.88, 95% CI 1.37-2.41 for a 1 SD increase in log endostatin values). CONCLUSION: Endostatin levels are independently associated with incident CVE in CKD patients, but show limited prediction abilities for all-cause mortality and CVE above traditional and renal-specific risk factors.

Relevance of uric acid and asymmetric dimethylarginine for modeling cardiovascular risk prediction in chronic kidney disease patients.

BACKGROUND: Both elevated serum uric acid and serum asymmetric dimethylarginine (ADMA) are risk factors for cardiovascular disease. We hypothesized that combined elevation of uric acid and ADMA amplifies the risk of all-cause mortality and/or cardiovascular events (CVE) in patients with chronic kidney disease (CKD). METHODS: A total of 259 patients with CKD stages 1-5 were followed up in a time-to-event analysis for all-cause mortality and fatal and non-fatal CVE (including death, stroke, and myocardial infarction). Baseline measurements included serum uric acid and ADMA and endothelial function [ultrasound determined flow-mediated dilatation (FMD)]. RESULTS: As a measure of endothelial function, log FMD value was positively associated with log eGFR, but negatively associated with log ADMA and log uric acid levels. During follow-up (median 38 months), 24 (9.3 %) deaths, 90 (34.7 %) CVE, and 95 (36.7 %) deaths and CVE (composite outcome) occurred. In the univariate Cox analysis, patients with both serum uric acid and ADMA levels above the median had an increased risk of all-cause mortality, CVE, and the composite outcome (HR 5.06, 95 % CI 2.01-12.76; HR 4.75, 95 % CI 2.98-7.59; and HR 4.13, 95 % CI 2.66-6.43, respectively). However, after adjustment for renal-specific risk factors (glomerular filtration rate, proteinuria, and hsCRP), this association was maintained only for CVE and the composite outcome. The addition of both biomarkers into a model with traditional and renal-specific risk factors did not increase the prediction abilities of the model for none of the three outcomes. CONCLUSION: Elevated serum uric acid and ADMA levels are associated with an increased cardiovascular risk, but their combination does not improve risk prediction. The effects are not additive, possibly because uric acid may lie in the causal pathway by which ADMA acts.

Effects of androgen replacement therapy on cornea and tear function in men with idiopathic hypogonadotropic hypogonadism.

PURPOSE: Idiopathic hypogonadotropic hypogonadism (IHH) is an endocrine disorder defined with the presence of typical clinical signs and symptoms plus laboratory confirmation of serum testosterone (T) levels lower than 300 ng/dl. Androgen replacement therapy (ART) is the first-step treatment of male IHH. To date, no clinical trial, which investigates the changes on corneal structure and tear function, of systemic ART in men have been published. The objective of this study was to investigate the effects of ART on cornea and tear function in patients with IHH. MATERIALS AND METHODS: This prospective, interventional study was conducted at the Gulhane Military Medical Academy, Ankara, Turkey, a tertiary referral military hospital. Thirty-four eyes of 17 men with IHH patients were evaluated with Schirmer I test, ultrasound pachymeter, applanation tonometer and confocal microscopy. A Testosterone compound (Sustanon® 250 mg) was administered by intramuscular injection in the course of a 3-week period to induce puberty, and human chorionic gonadotropin (Pregnyl® 5000 IU) was administered twice weekly for 3 months to induce fertility. The patients were re-evaluated at the third month of the treatment. Main Outcome Measures were Schirmer score, central corneal thickness (CCT), intraocular pressure (IOP), endothelial cell density, coefficient of variation and cell shape. RESULTS: Schirmer scores showed similar results after the treatment compared to pre-treatment levels (p = 0.14). There was no statistically significant difference in CCT and IOP compared to baseline data (p = 0.96, p = 0.73, respectively), and no significant differences were found in corneal endothelial cell density, percentage of cell size variability or hexagonality (p = 0.83, p = 0.58, p = 0.64, respectively). CONCLUSIONS: This is the first study that investigates the effects of ART on corneal structure and tear function in men. ART seems to have no short-term effects on corneal structure and tear function. Further publications of larger, long-term and controlled studies are needed.

A longitudinal study of inflammation, CKD-mineral bone disorder, and carotid atherosclerosis after renal transplantation.

BACKGROUND AND OBJECTIVES: The role of reversibility of nontraditional risk factors, like inflammation and CKD-mineral bone disorder, in the reduction of cardiovascular risk after renal transplantation is still scarcely defined. DESIGN, SETTING, PARTICIPANTS, AND MEASUREMENTS: The longitudinal relationship between C-reactive protein, CKD-mineral bone disorder biomarkers, and intima media thickness was investigated in a series of 178 patients (age=32±10 years) with stage 5 CKD maintained on chronic dialysis who underwent echo-color Doppler studies of the carotid arteries before and after renal transplantation. Smokers and patients with diabetes were excluded from the study. In all patients, immunosuppression was performed by a standard regimen on the basis of calcineurin inhibitors. Healthy controls were specifically selected to match the age and sex distribution of the patients. Biochemical and intima media thickness assessments were repeated 6 months after transplantation. RESULTS: Before transplantation, intima media thickness in patients with stage 5 CKD on dialysis (average=0.9±0.2 mm) was higher (P<0.001) than in well matched healthy controls (0.6±0.1 mm) and reduced substantially (-22%; 95% confidence interval, -24% to -20%) after transplantation (P=0.001). GFR (multivariable-adjusted ß=0.23; P<0.001), C-reactive protein (ß=0.15; P<0.001), and fibroblast growth factor 23 (ß=0.28; P<0.001) were the strongest independent correlates of intima media thickness before transplantation. Similarly, longitudinal changes in the same biomarkers were the sole independent correlates of simultaneous changes in intima media thickness (C-reactive protein: ß=0.25; fibroblast growth factor 23: ß=0.26; P<0.001 for both) after renal transplantation. The evolution of intima media thickness after transplantation was largely independent of classic risk factors, including BP, LDL cholesterol, and insulin resistance, as measured by homeostatic model assessment. CONCLUSIONS: Intima media thickness improves after renal transplantation. Such an improvement associates with parallel changes in serum C-reactive protein and fibroblast growth factor 23. These observations are in keeping with the hypothesis that the decline in cardiovascular risk after transplantation, in part, depends on partial resolution of nontraditional cardiovascular risk factors, like inflammation and CKD-mineral bone disorder.