Pentraxin-3 - a potential biomarker in ANCA-associated vasculitis.

OBJECTIVE: The aim of this study was to investigate pentraxin-3 (PTX3) as a potential biomarker of inflammatory activity in patients with anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) at baseline and 6 month follow-up in a longitudinal cohort. METHOD: Plasma PTX3 levels were measured in 79 newly diagnosed or relapsing AAV patients at baseline and 6 month follow-up, and in 23 healthy controls. Urinary PTX3 levels were measured in 34 of the patients. C-reactive protein (CRP), creatinine, and albuminuria were measured and the cumulative glucocorticoid dose at inclusion was calculated. The Birmingham Vasculitis Activity Score (BVAS) was assessed at baseline and follow-up. RESULTS: Plasma PTX3 levels were significantly higher at baseline than at 6 months (2.85 vs 1.23 ng/mL, p < 0.001). Plasma and urinary PTX3 levels correlated with BVAS at baseline (ρ = 0.45, p < 0.001, and ρ = 0.49, p = 0.008, respectively). A significant correlation between both plasma and urinary PTX3 levels and estimated glomerular filtration rate and albuminuria was found. However, there was no correlation between plasma and urinary PTX3 levels. At baseline, plasma and urinary PTX3 levels were significantly higher in patients with kidney involvement. PTX3 levels did not correlate with CRP, nor was there a correlation between CRP levels and BVAS at baseline. CONCLUSION: Plasma and urinary PTX3 seem to reflect disease activity in AAV better than the commonly used CRP. PTX3 may have a potential role as a biomarker in monitoring disease activity in AAV patients, particularly in patients with kidney involvement.

Time-dependent lipid profile inversely associates with mortality in hemodialysis patients - independent of inflammation/malnutrition.

BACKGROUND: Patients with end-stage kidney disease have an extremely high cardiovascular mortality rate, but there is a paradoxical relationship between lipid profile and survival in haemodialysis patients. To investigate whether inflammation/malnutrition confounds the associations between lipids and mortality, we studied a full lipid profile comprising of five clinically well-established lipid parameters and its associations with mortality in a large, multinational European cohort with a median follow-up >3 years. METHODS: The association between quartiles of total, high-density lipoprotein (HDL), non-HDL, low-density lipoprotein (LDL) cholesterol, as well as triglyceride, levels and the end-points of all-cause, cardiovascular and non-cardiovascular mortality was assessed in a cohort of 5,382 incident, adult haemodialysis patients from >250 Fresenius Medical Care dialysis centres out of 14 participating countries using baseline and time-dependent Cox models. Analyses were fully adjusted and stratified for inflammation/malnutrition status and other patient-level variables. RESULTS: Time-dependent quartiles of total, HDL, non-HDL and LDL cholesterol were inversely associated with the hazard for all-cause, cardiovascular and non-cardiovascular mortality. Compared with the lowest quartile of the respective lipid parameter, hazard ratios of other quartiles were <0.86. Similar, albeit weaker, associations were found with baseline lipid profile and mortality. Neither time-dependent nor baseline associations between lipid profile and mortality were affected by inflammation/malnutrition, statin use or geography. CONCLUSIONS: Baseline and time-dependent lipid profile are inversely associated with mortality in a large, multicentre cohort of incident haemodialysis patients. Inflammation/malnutrition is not a confounder nor effect modificator of the associations between lipid profile and mortality in European haemodialysis patients.

Phenotypic features of vascular calcification in chronic kidney disease.

BACKGROUND: Patients with chronic kidney disease stage 5 (CKD5) are predisposed to vascular calcification (VC), but the combined effect of factors associated with VC was sparsely investigated. We applied the relaxed linear separability (RLS) feature selection model to identify features that concomitantly associate with VC in CKD5 patients. METHODS: Epigastric arteries collected during surgery from living donor kidney transplant recipients were examined to score the histological extent of medial VC. Sixty-two phenotypic features in 152 patients were entered into RLS model to differentiate between no-minimal VC (n = 93; score 0-1) and moderate-extensive VC (n = 59; score 2-3). The subset of features associated with VC was selected on the basis of cross-validation procedure. The strength of association of the selected features with VC was expressed by the absolute value of 'RLS factor'. RESULTS: Among 62 features, a subset of 17 features provided optimal prediction of VC with 89% of patients correctly classified into their groups. The 17 features included traditional risk factors (diabetes, age, cholesterol, BMI and male sex) and markers of bone metabolism, endothelial function, metabolites, serum antibodies and mitochondrial-derived peptide. Positive RLS factors range from 1.26 to 4.05 indicating features associated with increased risk of VC, and negative RLS factors range from -0.95 to -1.83 indicating features associated with reduced risk of VC. CONCLUSION: The RLS model identified 17 features including novel biomarkers and traditional risk factors that together concomitantly associated with medial VC. These results may inform further investigations of factors promoting VC in CKD5 patients.

Different subclasses and isotypes of antibodies against phosphorylcholine in haemodialysis patients: association with mortality.

The risk of premature death is high among patients on haemodialysis (HD patients). We previously determined that immunoglobulin (Ig)M antibodies against phosphorylcholine (anti-PC) are negatively associated with increased risk of cardiovascular disease (CVD), atherosclerosis, some autoimmune diseases and mortality among HD patients in this cohort. Here, we also study other subclasses and isotypes of anti-PC in HD patients in relation to mortality, inflammation and gender. The study group is a cohort of 209 prevalent HD patients [median age = 66 years, interquartile range (IQR) = 51-74], vintage time = 29 months (IQR = 15-58; 56% men) with a mean follow-up period of 41 months (IQR = 20-60). Fifty-six per cent were men. We also divided patients into inflamed C-reactive protein (CRP) > 5·6 mg/ml and non-inflamed CRP. Antibody levels were determined by in-house enzyme-linked immunosorbent assay. IgG1 anti-PC below median was significantly associated with increased all-cause mortality (after adjustment for confounders: P = 0·02), while IgG, IgA and IgG2 anti-PC were not associated with this outcome. Among non-inflamed patients, IgM and IgG1 anti-PC were significantly associated with mortality (P = 0·047 and 0·02). IgG1 anti-PC was significantly associated with mortality among men (P = 0·03) and trending among women (P = 0·26). IgM (as previously reported) and IgG1 anti-PC are negatively associated with survival among HD patients and non-inflamed HD patients, but among inflamed patients there were no associations. IgG, IgA or IgG2 anti-PC were not associated with survival in these groups and subgroups. Further studies are needed to determine if raising anti-PC levels, especially IgM and IgG1 anti-PC, through immunization is beneficial.

Chemerin inhibits vascular calcification through ChemR23 and is associated with lower coronary calcium in chronic kidney disease.

BACKGROUND: Chemerin is an adipokine that signals through the G protein-coupled receptor ChemR23 and is associated with inflammation, glucose homeostasis, lipid metabolism and renal function, all of which strongly influence cardiovascular risk. However, elevated chemerin provides a survival advantage in patients with chronic kidney disease (CKD), but how this relates to the cardiovascular phenotype is unknown. OBJECTIVES: The aim of the present study was to establish the association of chemerin with coronary calcification and to determine the effects of chemerin signalling, through ChemR23, in vascular smooth muscle cell (VSMC) calcification. METHODS: Plasma chemerin was measured in 113 patients with CKD and 50 healthy controls. All patients underwent computed tomography to determine coronary artery calcium (CAC) score. VSMCs were isolated from wild-type and ChemR23 knock-out mice and treated with chemerin. RESULTS: Multivariate analyses established creatinine, cholesterol, body mass index and tumour necrosis factor as significant confounders for circulating chemerin levels. Despite these positive associations with renal function, cardiometabolic risk factors and inflammation, chemerin was inversely associated with CAC both in an age- and sex-adjusted analysis and in a multivariate analysis adjusting for the aforementioned confounders. In addition, circulating chemerin levels were associated with the calcification inhibitors matrix gla protein (MGP) and fetuin-A. Finally, chemerin significantly reduced phosphate-induced calcification and increased MGP expression in VSMCs, whereas chemerin was devoid of these effects in VSMCs lacking ChemR23. CONCLUSION: In conclusion, these results suggest that chemerin signalling through ChemR23 in VSMCs protects against vascular calcification in CKD.

Association between levels of pentraxin 3 and incidence of chronic kidney disease in the elderly.

OBJECTIVE: Higher levels of the novel inflammatory marker pentraxin 3 (PTX3) predict cardiovascular mortality in patients with chronic kidney disease (CKD). Yet, whether PTX3 predicts worsening of kidney function has been less well studied. We therefore investigated the associations between PTX3 levels, kidney disease measures and CKD incidence. METHODS: Cross-sectional associations between serum PTX3 levels, urinary albumin/creatinine ratio (ACR) and cystatin C-estimated glomerular filtration rate (GFR) were assessed in two independent community-based cohorts of elderly subjects: the Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS, n = 768, 51% women, mean age 75 years) and the Uppsala Longitudinal Study of Adult Men (ULSAM, n = 651, mean age 77 years). The longitudinal association between PTX3 level at baseline and incident CKD (GFR <60 mL(-1) min(-1) 1.73 m(-2) was also analysed (number of events/number at risk: PIVUS 229/746, ULSAM 206/315). RESULTS: PTX3 levels were inversely associated with GFR [PIVUS: B-coefficient per 1 SD increase -0.16, 95% confidence interval (CI) -0.23 to -0.10, P < 0.001; ULSAM: B-coefficient per 1 SD increase -0.09, 95% CI -0.16 to -0.01, P < 0.05], but not ACR, after adjusting for age, gender, C-reactive protein and prevalent cardiovascular disease in cross-sectional analyses. In longitudinal analyses, PTX3 levels predicted incident CKD after 5 years in both cohorts [PIVUS: multivariable odds ratio (OR) 1.21, 95% CI 1.01-1.45, P < 0.05; ULSAM: multivariable OR 1.37, 95% CI 1.07-1.77, P < 0.05]. CONCLUSIONS: Higher PTX3 levels are associated with lower GFR and independently predict incident CKD in elderly men and women. Our data confirm and extend previous evidence suggesting that inflammatory processes are activated in the early stages of CKD and drive impairment of kidney function. Circulating PTX3 appears to be a promising biomarker of kidney disease.

Associations of pain and depression with marital status in patients diagnosed with Parkinson's disease.

BACKGROUND: Depression and pain are significant clinical problems that are comorbid with Parkinson's disease (PD). However, the relationship of these variables with the marital status of patients with PD has not been explored in previous studies. Therefore, the goal of this study was to assess the possible relationship between depression prevalence, depression severity, and pain interference with the marital status of the sufferers of PD. METHODS: This study included 40 patients and 40 healthy control participants who were assessed for depression prevalence and severity using The Hospital Anxiety and Depression Scale (HADS). The same individuals were also assessed for pain interference using the Brief Pain Inventory (BPI). RESULTS: When compared to the control groups, the PD (Single) group was found to have the highest prevalence of depression, followed by the PD (Married) group whereas the Control (Single) group was found to have a higher prevalence than the Control (Married) group (P < 0.0001). A main effect was found on depression severity (P < 0.0001), but no significant differences were observed between the PD groups. Lastly, PD (Single) patients had significantly greater pain interference scores than the PD (Married) patients (P < 0.05) with no other significant case-control or control-control group differences. CONCLUSION: Patient-spouse relationship, which indicates physical and emotional support may have a mitigating effect on patient outcomes of depression prevalence and pain interference.

Clinical determinants and mortality predictability of stearoyl-CoA desaturase-1 activity indices in dialysis patients.

BACKGROUND: Stearoyl-CoA desaturase-1 (SCD-1) converts dietary saturated fatty acids to monounsaturated fatty acids. Elevated SCD-1 activity thus signifies impaired fatty acid metabolism and excess saturated fat intake. In the general population, increased SCD-1 activity is associated with cardiovascular disease and mortality. The determinants and implications of SCD-1 activity in dialysis patients are unknown. SUBJECTS: A total of 222 dialysis patients (39% women) with prospective follow-up, median age of 57 years and an average of 12 months of dialysis. DESIGN: Fatty acid compositions in plasma phospholipids and free fatty acids (FFAs) were assessed by gas-liquid chromatography. SCD-1 activity indices were calculated as the product-to-precursor fatty acid ratio (palmitoleic acid/palmitic acid) in each fraction to reflect SCD-1 activities in the liver and adipose tissue. RESULTS: Median hepatic and adipose tissue SCD-1 activity indices were 0.016 and 0.150, respectively. In multivariate analyses, SCD-1 was positively associated with age, female sex and serum interleukin-6 level. During 18.4 (interquartile range 5.5-37.3) months of follow-up, there were 61 deaths and 115 kidney transplants. The cut-off level for high SCD-1 indices was determined by receiver operating characteristic curve analyses. In fully adjusted competing risk models, patients with high SCD-1 indices in both phospholipids and FFAs had more than twofold increased mortality risk before kidney transplantation [hazard ratio (HR) 2.29, 95% confidence interval (CI) 1.28-4.11 and HR 2.36, 95% CI 1.38-4.03, respectively], compared with patients with low SCD-1 indices. CONCLUSIONS: Both hepatic and adipose tissue SCD-1 activity indices independently predict mortality in dialysis patients. Further studies are warranted to determine whether reducing SCD-1 activity by dietary intervention (limiting saturated fat) could improve survival in dialysis patients.

Plasma osteoprotegerin, arterial stiffness, and mortality in normoalbuminemic Japanese hemodialysis patients.

UNLABELLED: A high circulating osteoprotegerin (OPG) level may be a risk factor for vascular calcification and mortality in hemodialysis patients. OPG and pulse wave velocity (PWV) were measured at baseline in 151 normoalbuminemic, long-term (>3 years) Japanese hemodialysis patients who were prospectively followed for 6 years. In long-term normoalbuminemic Japanese hemodialysis patients, OPG levels were strongly linked with both arterial stiffness and worse outcome. INTRODUCTION: A high circulating OPG level is reported to be a risk factor for vascular calcification and mortality in Western chronic kidney disease (CKD) patients but it is not known if this is true for Japanese CKD patients, where a different risk profile may operate. METHODS: OPG and PWV were measured at baseline in 151 normoalbuminemic, long-term (>3 years) Japanese hemodialysis patients (median age 62 years) who were prospectively followed for 6 years. RESULTS: OPG levels were associated in multivariate analysis with age, dialysis vintage, history of cardiovascular disease (CVD) and parathyroid hormone levels. C-reactive protein levels did not correlate with OPG. Patients with clinical history of CVD had significantly higher OPG levels and OPG levels were positively correlated to PWV, an index of arterial stiffness. These associations were independent of age, sex, dialysis vintage, and diabetes. During the follow-up period, 40 deaths, including 25 cardiovascular deaths, were recorded. In crude analysis, each unit of increase in OPG was associated with increased all-cause (hazard ratios 1.14, 95% confidence interval 1.08-1.20) and CVD mortality (1.14 [1.07-1.21]), which persisted after adjustment for age, sex, dialysis vintage, diabetes, and baseline CVD (1.12 [1.05-1.19] and 1.11 [1.02-1.19], all-cause and CVD mortality, respectively). CONCLUSIONS: In long-term normoalbuminemic Japanese hemodialysis patients, with low prevalence of inflammation, OPG levels were strongly linked with both arterial stiffness and worse outcome.

Whole blood cytokine attenuation by cholinergic agonists ex vivo and relationship to vagus nerve activity in rheumatoid arthritis.

OBJECTIVE: The central nervous system regulates innate immunity in part via the cholinergic anti-inflammatory pathway, a neural circuit that transmits signals in the vagus nerve that suppress pro-inflammatory cytokine production by an alpha-7 nicotinic acetylcholine receptors (alpha7nAChR) dependent mechanism. Vagus nerve activity is significantly suppressed in patients with autoimmune diseases, including rheumatoid arthritis (RA). It has been suggested that stimulating the cholinergic anti-inflammatory pathway may be beneficial to patients, but it remains theoretically possible that chronic deficiencies in this pathway will render these approaches ineffective. METHODS: Here we addressed the hypothesis that inflammatory cells from RA patients can respond to cholinergic agonists with reduced cytokine production in the setting of reduced vagus nerve activity. RESULTS: Measurement of RR interval variability (heart rate variability, HRV), in RA patients (n = 13) and healthy controls (n = 10) revealed that vagus nerve activity was significantly depressed in patients. Whole blood cultures stimulated by exposure to endotoxin produced significantly less tumour necrosis factor in samples from RA patients as compared to healthy controls. Addition of cholinergic agonists (nicotine and GTS-21) to the stimulated whole blood cultures however significantly suppressed cytokine production to a similar extent in patients and healthy controls. CONCLUSION: These findings suggest that it is possible to pharmacologically target the alpha7nAChR dependent control of cytokine release in RA patients with suppressed vagus nerve activity. As alpha7nAChR agonists ameliorate the clinical course of collagen induced arthritis in animals, it may be possible in the future to explore whether alpha7nAChR agonists can improve clinical activity in RA patients.

Temporal discrepancies in the association between the apoB/apoA-I ratio and mortality in incident dialysis patients.

BACKGROUND: In the general population, a high apoB/apoA-I ratio is a strong risk factor for cardiovascular disease and mortality. However, whether this is the case in chronic kidney disease (CKD) patients is currently unknown. STUDY DESIGN: The apoB/apoA-I ratio was evaluated in 391 incident CKD stage 5 patients examined close to dialysis initiation, and again after 1 year of dialysis in a subgroup of 182 patients, subsequently followed for up to 3 years. RESULTS: Baseline values of the apoB/apoA-I ratio as well as changes in the ratio during the first year of dialysis correlated with body mass index (BMI) and fat mass. The baseline apoB/apoA-I ratio showed no association with 4-year mortality. However, after adjustment for confounders, a high apoB/apoA-I ratio (>0.9) predicted short-term (first year) survival [hazard ratio (HR): 0.35; 95% confidence interval (CI): 0.13-0.85)] and long-term (next 3 years) mortality (HR: 1.72; 95% CI: 1.01-2.96). An increase in the apoB/apoA-I ratio during the first year of dialysis was linked to a survival advantage thereafter (HR: 0.48; 95% CI: 0.22-0.98). However, this association lost its significance (HR: 0.62; 95% CI: 0.26-1.36) after adjustment for indices of protein-energy wasting. CONCLUSIONS: A high apoB/apoA-I ratio and an increase in this ratio during the first year on dialysis were associated with short-term survival advantage in CKD patients. This paradoxical relationship represents an example of the so-called reverse epidemiology phenomenon in CKD patients and suggests that the apoB/apoA-I ratio should always be interpreted with caution in this patient population.

Effects of Probiotic Supplementation on Trimethylamine-N-Oxide Plasma Levels in Hemodialysis Patients: a Pilot Study.

Components present in the diet, L-carnitine, choline, and betaine are metabolized by gut microbiota to produce metabolites such as trimethylamine-N-oxide (TMAO) that appear to promote cardiovascular disease in chronic kidney disease (CKD) patients. The objective of this pilot study was to evaluate the effects of probiotic supplementation for 3 months on plasma TMAO levels in CKD patients on hemodialysis (HD). A randomized, double-blind trial was performed in 21 patients [54.8 ± 10.4 years, nine men, BMI 26.1 ± 4.8 kg/m2, dialysis vintage 68.5 (34.2-120.7) months]. Ten patients were randomly allocated to the placebo group and 11 to the probiotic group [three capsules, totaling 9 × 1013 colony-forming units per day of Streptococcus thermophilus (KB19), Lactobacillus acidophilus (KB27), and Bifidobacteria longum (KB31). Plasma TMAO, choline, and betaine levels were measured by LC-MS/MS at baseline and after 3 months. While TMAO did not change after probiotic supplementation, there was a significant increase in betaine plasma levels. In contrast, the placebo group showed a significant decrease in plasma choline levels. Short-term probiotic supplementation does not appear to influence plasma TMAO levels in HD patients. Long-term studies are needed to determine whether probiotics may affect TMAO production in CKD patients.

Telomere attrition is associated with inflammation, low fetuin-A levels and high mortality in prevalent haemodialysis patients.

INTRODUCTION: Chronic kidney disease (CKD) predisposes to a 10- to 20-fold increased cardiovascular risk. Patients undergo accelerated atherogenesis and vascular ageing. We investigated whether telomere attrition, a marker of cell senescence, contributes to this increased mortality risk. METHODS: This is a cross-sectional study in prevalent haemodialysis patients [n = 175; 98 Males; median (range) age: 66 (23-86) years]. Biochemical markers of oxidative stress and inflammatory status were measured in relation to the patient's leucocyte telomere length. Overall mortality was assessed after a median of 31 (range 2-42) months. RESULTS: Telomere length was shorter in CKD men, despite women being older (average +/- SD 6.41 +/- 1.23 vs. 6.96 +/- 1.48 kb, P = 0.002). Telomere length was associated with age (rho = -0.18, P = 0.01), fetuin-A (rho = 0.26, P = 0.0004), high-sensitivity C-reactive protein (rho = -0.21, P = 0.005) and IL-6 (rho = -0.17, P = 0.02). In a multivariate logistic regression (pseudo r(2) = 0.14), telomere length was associated with age >65 years (odds ratio: 2.11; 95% CI: 1.10, 4.06), sex (2.01; 1.05, 3.86), fetuin-A (1.85; 0.97, 3.50) and white blood cell count (2.04; 1.02, 4.09). Receiver operating characteristic curves identified a telomere length < 6.28 kb as a fair predictor of mortality. Finally, reduced telomere length was associated with increased mortality, independently of age, gender and inflammation (likelihood ratio 41.6, P < 0.0001), but dependently on fetuin-A levels. CONCLUSION: Age and male gender seem to be important contributors to reduced telomere length in CKD patients, possibly via persistent inflammation. Reduced telomere length also contributes to the mortality risk of these patients through pathways that could involve circulating levels of fetuin-A.

Low serum fetuin-A concentration predicts poor outcome only in the presence of inflammation in prevalent haemodialysis patients.

BACKGROUND: Fetuin-A, a negative acute phase protein that inhibits vascular calcification, has a controversial association with mortality in chronic kidney disease (CKD) patients. Chronic inflammation, which is common in CKD, may promote vascular calcification. MATERIALS AND METHODS: We investigated the impact of inflammation on the relationship between serum fetuin-A and mortality (42 months) in 222 prevalent haemodialysis (HD) patients. RESULTS: Serum fetuin correlated negatively with comorbidity score (assessed by Davies score) and circulating inflammatory markers. Patients with low fetuin-A levels (< median) had higher mortality (Hazard ratio 'HR' 2.2; CI 1.4-3.5, P < 0.001), but this association was lost after adjustment for age, gender, comorbidities score, dialysis vintage and inflammation (CRP > median). In inflamed patients with low fetuin a significantly independent association with mortality (HR 2.3; CI 1.2-4.5, P = 0.01) was observed compared to non-inflamed patients with high fetuin-A, after adjusting for the same variables. Non-inflamed patients with low fetuin-A and inflamed patients with high fetuin-A did not have increased mortality compared to non-inflamed patients with high fetuin-A. CONCLUSIONS: The results show that low levels of serum fetuin-A are associated with increased mortality in HD patients only in the presence of inflammation. This suggests that coexistence of a low serum fetuin-A level and low-grade inflammation exerts an additive effect on the risk of death in HD patients.

The Brazilian Peritoneal Dialysis Multicenter Study (BRAZPD) : characterization of the cohort.

The Brazilian Peritoneal Dialysis Multicenter Study (BRAZPD) was launched in December 2004 aiming to collect data monthly and continuously from a representative cohort, allowing for a continuous snapshot of the peritoneal dialysis (PD) reality in the country. This is an observational study of PD patients comprising follow-up from December 2004 to February 2007 (mean follow-up of 13.6 months-ranging from 1 to 26 months) in 114 Brazilian centers. All centers report data through a central web-based database. After an initial baseline retrospective data collection, all patients are followed prospectively every month until they drop out from the PD program. Total number of patients recruited until February 2007 was 3226 (2094 incident patients). Mean age was 54+/-19 years (37% above 65 years old), with 55% females and 64% Caucasians. The more frequent causes of renal failure were diabetic nephropathy (34%), renal vascular disease associated with hypertension (26%), and glomerulopathies (13%). The most common comorbidities were hypertension (76%), diabetes (36%), and ischemic heart disease (23%). Automated PD (APD) was the modality utilized in 53%. The estimated overall peritonitis rate was 1 episode per 30 patient-months (most frequently due to Staphylococcus aureus). The total dropout rate was 33%, mainly due to deaths, whereas 20% of dropouts were due to renal transplant. The gross mortality was 17.6% and the main causes of mortality were cardiovascular diseases (40%) and infections (15%). The initial results of this first Brazilian PD registry provide a unique opportunity to develop future clinical studies addressing specific PD questions in the Brazilian reality and context.

Clinical and biochemical implications of low thyroid hormone levels (total and free forms) in euthyroid patients with chronic kidney disease.

OBJECTIVES: In this study, we explore the associations of decreased thyroid hormone levels with inflammation, wasting and survival in biochemically euthyroid patients with end-stage renal disease (ESRD). DESIGN: After exclusion of 23 patients with thyroid-stimulating hormone (TSH) values outside the normal range (0.1-4.5 mIU L(-1)), 187 clinically and biochemically euthyroid incident ESRD stage 5 patients starting dialysis were followed for a median of 20 (range 1-60) months. Measurements of total and free forms of thyroid hormones, s-albumin, hs-CRP, interleukin (IL)-6, vascular adhesion molecule (VCAM)-1 and insulin-like growth factor 1 (IGF-1) were performed at baseline. RESULTS: In this population, 17 out of 210 patients (8%) were defined as subclinically hypothyroid. Multivariate analysis, according to receiver operating characteristic (ROC) curves, showed that mortality was best predicted by total triiodothyronine (T3). When using the cut-off levels derived from ROC, low T3 levels were associated with increased inflammation (higher hs-CRP, IL-6 and VCAM-1) and lower concentration of both s-albumin and IGF-1. Finally, low T3 but not low free triiodothyronine was associated with worse all-cause (Likelihood ratio = 45.4; P < 0.0001) and cardiovascular mortality (Likelihood ratio = 47.8; P < 0.0001) after adjustment for confounding factors. CONCLUSION: This study showed that low T3 levels are independent predictors of all-cause and also cardiovascular disease mortality in biochemically euthyroid patients, perhaps due to an intimate association with inflammation. Based on these results, the use of T3 levels in studies assessing the relationship between thyroid dysfunction and mortality risk is recommended.

Gamma glutamyltranspeptidase activity and viral hepatitis in dialysis population.

BACKGROUND: Numerous investigations have reported that viral hepatitis is associated with significant hepatocellular damage, as expressed by raised aminotransferases in serum, in dialysis population. However, scarce information exists on the activity of gamma glutamyltranspeptidase (GGTP) in dialysis patients with infection by hepatotropic viruses. OBJECTIVES: We measured serum GGTP values in a large cohort (n=757) of patients receiving long-term dialysis; healthy controls were also included. The relationship between GGTP values and a series of demographic, clinical, and biochemical parameters was analyzed. METHODS: Serum GGTP levels were tested by spectrophotometry. A subset (n=333) of dialysis patients was tested by molecular technology (branched-chain DNA (bDNA) assay) to evaluate the relationship between serum GGTP and HCV viremia. A subgroup (n=78) of dialysis patients was analyzed by an ultrasound scan of gallbladder and biliary tract to assess the presence of gallstone disease. Multivariate analyses were made using regression models; serum GGTP values were included as a dependent variable. The usefulness of serum GGTP levels in detecting HBsAg and anti-HCV positivity was evaluated using receiver operating characteristics (ROC) curve analysis. RESULTS: Univariate analysis showed that serum GGTP levels were significantly higher in HBsAg positive and/or anti-HCV positive patients than in HBsAg negative/anti-HCV negative patients on dialysis; 85.1+/-184.1 versus 25.86+/-23.9 IU/l (P=0.0001). The frequency of raised GGTP levels was 22.2% (41/184) among dialysis patients with chronic viral hepatitis. Multivariate analysis showed a significant and independent association between serum GGTP values and positive HBsAg (P=0.005) and anti-HCV antibody (P=0.0001) status. Mean GGTP values were significantly higher in study patients than controls, 32.32+/-60.02 versus 23.5+/-16.92 IU/L (P=0.01); however, no significant difference with regard to GGTP between study and healthy cohorts persisted after correction for age, gender, race, and viral markers. No relationship between gallstone disease and serum GGTP was found (NS). An independent and significant association (P=0.0291) between raised GGTP levels and detectable HCV RNA in serum was noted among patients tested by biology molecular techniques. ROC technology demonstrated that GGTP was equally useful for detecting HBV (P=0.0004) and HCV (P=0.0005) among dialysis patients. CONCLUSIONS: We found an independent and significant association between serum GGTP values and HBsAg and/or anti-HCV antibody in dialysis population. Twenty-two percent of dialysis patients with chronic viral hepatitis had elevated GGTP. No difference in GGTP between HBsAg- negative/anti-HCV- negative dialysis patients and healthy individuals was found. Routine testing for serum GGTP levels to assess liver disease induced by hepatotropic viruses or other agents in dialysis population is suggested.

Are insulin-like growth factor and its binding proteins 1 and 3 clinically useful as markers of malnutrition, sarcopenia and inflammation in end-stage renal disease?

INTRODUCTION: Malnutrition is common in end-stage renal disease (ESRD) and affects both morbidity and mortality. The growth hormone-dependent insulin-like growth factor (IGF)-I may be a good marker of malnutrition because of its short half-life. In the present study, we investigate the influence of decreasing residual renal function as well as of chronic inflammation on the IGF system to assess its usefulness in this patient group. PATIENTS AND METHODS: Cross-sectional analysis of 220 ESRD patients (140 males) with a mean age of 52+/-1 years. Biochemical analyses of insulin, IGF-I, IGFBP-1, IGFBP-3, IL-6, high sensitivity (hs)-CRP and other routine markers. Malnutrition status was recorded using subjective global assessment (SGA), body mass index, estimated protein intake from nitrogen appearance (nPNA), handgrip strength (HGS) and insulin resistance (HOMA-IR). Dual energy X-ray absorptiometry was used to assess body composition. RESULTS: Both IGF-I and IGFBP-1 showed significant and opposite correlations with most markers of nutritional status, including SGA (rho=-0.29 and 0.27; P<0.001), nPNA (rho=0.18 and -0.22; P<0.05), S-creatinine (rho=0.19 and -0.19; P<0.01) and HGS (rho=0.21 and -0.25; P<0.01). IFG-I was strongly correlated with IGFBP-3 (rho=0.62; P<0.001) and inversely correlated with IGFBP-1 (rho=0.44; P<0.001). Both IGF-I and IGFBP-3, but not IGFBP-1, were significantly correlated with age (rho=-0.25 for IGF-I and -0.35 for IGFBP-3; P<0.001) and hsCRP (rho=-0.21 and -0.32; P<0.01). In multivariate analysis, SGA and s-albumin were independent predictors of both IGF-I and IGFBP-1. CONCLUSION: Both IGF-I and IGFBP-1 appear to correlate well with markers of protein-energy malnutrition and sarcopenia. However, IGF-I is also influenced by age, whereas IGFBP-1 is influenced by glucose metabolism. IGFBP-3 does not correlate with nutritional status in ESRD, perhaps because of a strong association with inflammation.

Plasma pentosidine and total homocysteine levels in relation to change in common carotid intima-media area in the first year of dialysis therapy.

BACKGROUND: Homocysteine and advanced glycation end-products (AGEs), which accumulate in chronic kidney disease (CKD), are recently proposed cardiovascular risk factors. In this study, we evaluated the association between changes in calculated intima media (cIM) area of the common carotid artery during the first year of dialysis therapy and plasma total homocysteine (tHcy) level as well as circulating AGEs such as plasma pentosidine level. METHODS: We studied 63 CKD patients (38 males) aged 52 +/- 12 years at a time-point close to start of dialysis treatment and after 12 months of dialysis treatment (41 on peritoneal and 22 on hemodialysis). The tHcy and plasma pentosidine levels were measured by HPLC. Change in cIM area was evaluated by non-invasive B mode ultrasonography. Malnutrition was assessed by subjective global assessment (SGA). RESULTS: At basal, 70% of the patients had carotid plaques, 32% had symptomatic CVD, 38% had malnutrition, 30% had inflammation (CRP > or = 1 mg/dl) and 23% had diabetes mellitus, respectively. At baseline, the mean plasma pentosidine levels were similar in the patients with and without carotid plaques (36 +/- 21 vs 36 +/- 19 pmol/mg albumin, respectively), whereas the median plasma tHcy was significantly lower in the patients with carotid plaques than in the patients without carotid plaques (32 +/- 21 vs 52 +/- 42 pmol/l, p < 0.01, respectively). The prevalence of hyperhomocysteinemia (tHcy level > 13.7 micromol/l) was 95%. In univariate analysis, the change in cIM area during the first year of dialysis was significantly correlated with basal plasma pentosidine level (p = 0.31, p = 0.01), but not with basal tHcy (p = -0.11). However, neither pentosidine nor tHcy levels were correlated with cIM area at basal or at 12 months. In a stepwise multiple regression model, age and plasma pentosidine content, but not the tHcy level, associated with changes in the cIM area. CONCLUSION: Progression of atherosclerosis, as indicated by changes in carotid intima-media area during the course of dialysis treatment, was associated with pentosidine, but not with tHcy, levels at baseline in these CKD patients. This suggests that the accumulation of AGEs in CKD patients may have a role in the pathogenesis of CVD in these patients. Since almost all CKD patients have hyperhomocysteinemia, this finding, however, does not exclude a role ofhomocysteine as a risk factor for CVD in CKD patients.

Peroxisome proliferator-activated receptor gamma polymorphisms affect systemic inflammation and survival in end-stage renal disease patients starting renal replacement therapy.

BACKGROUND: Inflammation may contribute to the markedly increased cardiovascular morbidity and mortality in end-stage renal disease (ESRD). However, the prevalence of inflammation varies in different ESRD populations. Peroxisome proliferator-activated receptor-gamma (PPAR-gamma) is an important nuclear signaling protein that may regulate inflammatory response, and recent studies have revealed genetic polymorphisms that have significant effect on PPAR-gamma signaling. The aim of this study was to clarify whether the PPAR-gamma 161C/T and PPAR-gamma2 Pro12Ala single-nucleotide polymorphisms (SNPs) influence the inter-individual variance of inflammation and mortality in ESRD patients. METHODS: The present prospective study included 229 incident Caucasian ESRD patients (62% males) just prior to starting renal replacement therapy and 207 healthy controls (62% males). Blood samples were taken for measuring systemic inflammatory (CRP, TNF-alpha, IL-6) and nutritional (S-albumin) parameters. The presence of diabetes mellitus, malnutrition (subjective global assessment (SGA)) and cardiovascular disease (CVD) were also assessed. Genotyping of the two PPAR-gamma SNPs was performed using Pyrosequencing. During follow-up (1621+/-63 days), both all-cause and CVD-mortality were investigated. RESULTS: ESRD patients had a higher prevalence of both the PPAR-gamma 161 CC and PPAR-gamma2 Pro12Pro genotypes than the general population (p<0.01). Whereas the Pro12Pro genotype was associated with higher median serum levels of both hs-CRP (p<0.05) and TNF-alpha (p<0.01) the 161CC genotype was associated with a significantly higher (6.6 mg/L versus 3.3 mg/L; p<0.01) median hs-CRP level. Following adjustment for age, gender, SGA and CVD a significantly higher mortality rate was observed in patients with the Pro12Pro genotype. CONCLUSION: This study demonstrates significant differences in PPAR-gamma genotype distribution between ESRD patients and healthy controls. Furthermore, as the PPAR-gamma2 Pro12Pro genotype was associated with both higher levels of biomarkers of inflammation as well as shorter survival, genetic polymorphisms seem to play a role in determining systemic inflammatory status and outcome in this patient group.