Effects of Acute Fructose Loading on Markers of Inflammation-A Pilot Study.

Inflammation plays a role in development of diabetic complications. The postprandial state has been linked to chronic low grade inflammation. We therefore aimed to investigate the acute effects of fructose loading, with and without a pizza, on metabolic and inflammatory markers in patients with type 2 diabetes (T2D) (n = 7) and in healthy subjects (HS) (n = 6), age 47-76 years. Drinks consumed were blueberry drink (18 g fructose), Coca-Cola (17.5 g fructose), and fructose drink (35 g fructose). The levels of glucose, insulin, insulin-like growth factor binding protein-1 (IGFBP-1) and inflammatory markers: Interleukin-6 (IL-6), Monocyte chemoattractant protein-1 (MCP-1), Interleukin-18 (IL-18), Intercellular Adhesion Molecule 1 (ICAM-1), vascular cell adhesion molecule 1 (VCAM-1), and bacterial lipopolysaccharides (LPS) were analyzed in blood. The postprandial responses were assessed using Wilcoxon's matched-pairs test, Friedman's ANOVA and Mann-Whitney U test. There was no difference in baseline levels of inflammatory markers between the groups. In T2D, MCP-1 decreased following blueberry drink and Coca-Cola (p = 0.02), Coca-Cola + pizza and fructose + pizza (p = 0.03). In HS, IL-6 increased following blueberry + pizza and fructose + pizza (p = 0.03), there was a decrease in MCP-1 following blueberry drink and Coca-Cola (p = 0.03), and in ICAM-1 following blueberry + pizza (p = 0.03). These results may indicate a role for MCP-1 as a link between postprandial state and diabetes complications, however further mechanistic studies on larger population of patients with T2D are needed for confirmation of these results.

Skin autofluorescence, arterial stiffness and Framingham risk score as predictors of clinical outcome in chronic kidney disease patients: a cohort study.

BACKGROUND: The risk of cardiovascular disease (CVD) is predicted by Framingham's CVD risk scores (FRS) but the high CVD-related mortality in patients with chronic kidney disease (CKD) is only partially explained by traditional CVD risk markers. Therefore, there is a need to explore whether other CVD risk markers may improve risk prediction. Although arterial stiffness measured by augmentation index (AIx) and tissue content of advanced glycation end-products (AGEs) measured by skin autofluorescence (SAF) are two biomarkers that associate with CVD and mortality in CKD, it is not known how they compare with FRS. We evaluated associations between SAF, AIx and FRS, and their associations with CVD and mortality in CKD patients. METHODS: SAF (AGE Reader) and AIx (SphygmoCor; adjusted for 75 heart beats per minute) were measured in 261 clinically stable and extensively phenotyped patients with CKD Stage 5 (median age 56 years, 66% male, 20% diabetes; 130 non-dialysed, 93 patients on peritoneal dialysis and 38 patients on haemodialysis). Multivariate receiver operator characteristics (ROC) curve analysis and multivariate Cox models followed by C-statistics were used to evaluate CVD-related and all-cause mortality risk associated with SAF, AIx and FRS during follow-up for median 25 months with 46 deaths. RESULTS: In multivariate regression analysis, SAF associated with FRS, haemoglobin, fat body mass index and CVD, and inversely with per cent handgrip strength (HGS). AIx associated with FRS, and inversely with per cent HGS. Associations of SAF and AIx with high-sensitivity C-reactive protein (hsCRP), serum albumin, statin therapy and renal replacement therapy were not statistically significant. In ROC analysis, area under the curve (AUC) for CVD mortality ranged from AUC = 0.72 (AIx and FRS, respectively) to AUC = 0.78 (FRS + AIx), and for all-cause mortality from AUC = 0.70 (AIx) to AUC = 0.79 (FRS + AIx). In multivariate Cox analysis, after adjusting for 1-standard deviation (1-SD) of FRS, 1-SD increase of SAF associated with all-cause mortality and 1-SD increase of AIx associated with CVD mortality and all-cause mortality. After further adjustments for hsCRP, albumin and presence of CVD, AIx (but not SAF) remained independently associated with CVD mortality, hazard ratio (HR) 2.14 [95% confidence interval (95% CI) 1.18-3.89] and all-cause mortality, HR 1.74 (95% CI 1.16-2.60). CONCLUSIONS: In patients with CKD Stage 5, SAF and aortic stiffness associated with mortality, independently of FRS. After adjusting for additional confounders including inflammation, aortic stiffness remained as an independent predictor of outcome. Since the contribution of SAF and aortic stiffness compared with FRS in ROC curve analysis was relatively modest, this underlines the importance of traditional CVD risk factors in CKD.

Effects of acute fructose loading on levels of serum uric acid-a pilot study.

BACKGROUND: Fructose intake may lead to hyperuricaemia, which is associated with increased risk and progression of kidney disease. We aimed to explore the acute effects of fructose loading from different sources, with and without a pizza, on levels of serum uric acid in patients with chronic kidney disease (CKD), type 2 diabetes (T2D) without CKD, and in healthy subjects (HS). METHODS: The study included six HS, and three CKD stage 4-5 and seven T2D patients. Drinks consumed were blueberry drink (17.5 g fructose), Coca-Cola (18 g fructose) and fructose drink (35 g fructose). The drinks were also combined with pizza, in total six interventions. Serum samples were collected fasting and 30, 60, 90 and 120 minutes after intake and also 240 minutes after drink + pizza, and analysed for fructose, uric acid and triglycerides. Postprandial responses were explored using repeated-measure ANOVA. RESULTS: Baseline serum uric acid levels were increased in CKD (P = 0.037). There were significant differences in serum fructose and serum uric levels over time between drinks and drinks + pizza for all groups (P < 0.001 and P < 0.05, respectively). The highest peak in serum fructose followed the fructose drink interventions and the lowest the blueberry drink. The fructose drink interventions gave the highest responses in serum uric acid and the lowest responses followed the blueberry drink. Triglycerides increased following pizza interventions (P < 0.001). CONCLUSIONS: Intake of fructose increases serum uric acid. The fructose intake via a blueberry drink induced lowest increase and thus may be protective.

Serum Glutaredoxin Activity as a Marker of Oxidative Stress in Chronic Kidney Disease: A Pilot Study.

BACKGROUND: Inflammation and oxidative stress play important roles in the pathogenesis and progression of chronic kidney disease (CKD) and in its complications, in particular cardiovascular disease, a major cause of death among patients undergoing dialysis treatment. We recently described that Glutaredoxin1 (Grx), an intracellular antioxidant, catalyzes oxidoreductase reactions also extracellularly, and that serum Grx levels correlate to disease severity in type 2 diabetes. AIM: In the current study we assess Grx as a potential clinical marker of oxidative stress in CKD. METHODS: We examined Grx activity in 25 patients with different stages of chronic kidney failure, 19 control subjects, and 36 patients at initiation of dialysis and after 2 years of dialysis. RESULTS: We found that Grx activity was significantly higher in CKD patients compared to control subjects, indicating an oxidized extracellular environment in CKD. Grx levels correlated to interleukin-6 and pentosidine, but not to age or GFR. In dialysis patients with Grx sampling before dialysis start and after 2 years of dialysis, Grx levels increased more in hemodialysis (HD) patients than in peritoneal dialysis patients, indicating an increased oxidative stress imbalance in HD patients. Patients who experienced a stroke or myocardial infarction at any time had a significantly higher increase in Grx during the 2 years of dialysis, compared to patients without stroke or myocardial infarction, indicating a possible association between high Grx levels and a cardiovascular event. CONCLUSION: Our pilot study indicates that Grx may be a useful marker for assessing the degree of oxidative stress in CKD, however this needs further investigation in a larger prospective patient cohort.

Inflammation down-regulates CYP3A4-catalysed drug metabolism in hemodialysis patients.

BACKGROUND: Recent studies indicate that inflammation may also affect CYP3A4 activity. Associations of CYP3A4-mediated metabolism of quinine, with inflammatory biomarkers were investigated in patients undergoing maintenance hemodialysis (HD). METHODS: A single dose of 100 mg quinine was given to 44 HD patients and the plasma concentration of quinine and its metabolite 3-OH-quinine were measured 12 h after drug intake. The ratios of quinine/3-OH-quinine and 4ß-OH-cholesterol/cholesterol were used as markers of CYP3A4 activity. Inflammatory biomarkers, high-sensitive CRP (hsCRP), pentraxin 3 (PTX3) and orosomucoid were followed during 4 weeks prior to quinine administration. RESULTS: The quinine/3-OH-quinine ratio correlated with median concentrations of hsCRP (Rho = 0.48; p = 0.001) and orosomucoid (Rho = 0.44; p = 0.003), and also with interleukin-6 at 12 h after drug intake (Rho = 0.43; P = 0.004) but not PTX3. In multivariate regression analysis, the correlation between CYP3A4 activity and median hsCRP remained borderline significant (p = 0.05). 4ß-OH-cholesterol/cholesterol ratio correlated with quinine/3-OH-quinine (p = 0.008), but not with any of the inflammation markers. CONCLUSIONS: The association between CYP3A4 activity and inflammatory biomarkers suggest that the activity of CYP3A4 is reduced by inflammation in HD patients. Further studies are needed to confirm this finding and to assess to what extent magnitude and duration of inflammation as well as the microbiota affect drug metabolism.

Brown adipose tissue in young adults who were born preterm or small for gestational age.

BACKGROUND: Brown adipose tissue (BAT) is present and functions to dissipate energy as heat in young adults and can be assessed using magnetic resonance imaging (MRI) to estimate the voxel fat fraction, i.e. proton density fat fraction (PDFF). It is hypothesized that subjects born preterm or small for gestational age (SGA) may exhibit disrupted BAT formation coupled to metabolic factors. Our purpose was to assess the presence of BAT in young adults born extremely preterm or SGA in comparison with controls. METHODS: We studied 30 healthy subjects (median age, 21 years): 10 born extremely preterm, 10 full term but SGA and 10 full term with a normal birth weight (controls). We utilized an MRI technique combining multiple scans to enable smaller echo spacing and an advanced fat-water separation method applying graph cuts to estimate B0 inhomogeneity. We measured supraclavicular/cervical PDFF, R2*, fat volume, insulin-like growth factor 1, glucagon, thyroid stimulating hormone and the BAT-associated hormones fibroblast growth factor 21 and irisin. RESULTS: The groups did not significantly differ in supraclavicular/cervical PDFF, R2*, fat volume or hormone levels. The mean supraclavicular/cervical PDFF was equivalent between the groups (range 75-77%). CONCLUSIONS: Young adults born extremely preterm or SGA show BAT development similar to those born full term at a normal birth weight. Thus, the increased risk of cardiovascular and metabolic disorders in these groups is not due to the absence of BAT, although our results do not exclude possible BAT involvement in this scenario. Larger studies are needed to understand these relationships.

Restrictive lung disorder is common in patients with kidney failure and associates with protein-energy wasting, inflammation and cardiovascular disease.

BACKGROUND: Cardiovascular disease (CVD), protein-energy wasting (PEW), and inflammation are common interrelated features of chronic kidney disease (CKD). Less is known about lung dysfunction in CKD and its possible role in this context. We evaluated lung function and its association with estimated glomerular filtration rate (GFR), CVD, PEW, and inflammation in individuals with normal to severely reduced GFR. METHODS: In 404 individuals with GFR category G1 (n = 31; GFR >90mL/min/1.73 m2), G2 (n = 46), G3 (n = 33), G4 (n = 49) and G5 (n = 245; GFR<15mL/min/1.73 m2), pulmonary function was assessed by spirometry. Obstructive (OLD) and restrictive (RLD) lung dysfunction was defined based on forced vital capacity (FVC), forced expiratory volume in the first second (FEV1) and peak expiratory flow (PEF), expressed as percentages of predicted values (%FEV1, %FVC and %PEF, respectively). PEW was evaluated by subjective global assessment, handgrip strength (HGS) and lean body mass index (LBMI), and inflammation by interleukin-6 and high sensitivity C-reactive protein. RESULTS: RLD (defined as FEV1/FVC ≥ 0.70 and %FVC<80) associated with GFR and was present in 36% of G5 and 14% of G1-4 individuals. OLD (FEV1/FVC<0.70) was less common with similar prevalence among G1-4 (9%) and G5 (11%) individuals. Notably, 64% of those with concomitant presence of PEW, inflammation and clinical signs of CVD had RLD while 79% of those lacking these complications had normal lung function. In multivariate logistic regression analysis, RLD associated with CVD, PEW and inflammation, after adjusting for Framingham's CVD risk score, serum albumin, and GFR category. CONCLUSIONS: RLD is a common complication in patients with advanced CKD, especially in those with concomitant presence of CVD, inflammation and PEW. RLD appears to be an integral albeit scarcely explored consequence of pulmonary-renal interactions in CKD patients.

Plasma Beta-Trace Protein as a Marker of Residual Renal Function: The Effect of Different Hemodialysis Modalities and Intra-Individual Variability over Time.

BACKGROUND/AIMS: Beta-trace protein (BTP) is a low-molecular-weight molecule, which may be used to assess residual renal function (RRF) in dialysis patients. Here we evaluated the influence of hemodialysis (HD) and hemodiafiltration (HDF) on plasma BTP, and analyzed the inter- and intra-individual variability of plasma BTP over time in HD and peritoneal dialysis (PD) patients. METHODS: In 12 prevalent HD patients, the effect of a single session of low-flux HD, high-flux HD and HDF on plasma BTP was studied. Blood samples were taken at baseline, after 120 and 240 minutes, and at the start of the next dialysis session. In 13 HD patients and 10 PD patients, inter- and intra-individual variability over three months was studied (monthly and weekly, respectively). Plasma BTP was measured using a nephelometric method. RESULTS: No significant decrease in plasma BTP was seen following a session of low-flux HD. Both high-flux HD and HDF resulted in a significant decrease immediately after dialysis (22% and 61% median decrease, respectively). A significant reduction of the molecule persisted only in HDF and a significant decrease (-15%) was still found immediately before the start of the next dialysis session. In both HD and PD patients, the reproducibility over time was excellent with intra-class correlation coefficient of 0.96 (0.93-0.99) and 0.92 (0.86-0.99) respectively. In a small cohort of PD patients, fair agreement existed between mGFR (average of renal urea and creatinine clearance from a 24 hours urine collection) and the BTP-based GFR estimation. CONCLUSION: BTP is a stable marker and a promising tool for RRF estimations in PD and HD patients. In patients receiving HDF, plasma levels of BTP should be interpreted with caution.

Total and bone-specific alkaline phosphatase are associated with bone mineral density over time in end-stage renal disease patients starting dialysis.

BACKGROUND: Alkaline phosphatase (ALP) and bone-specific ALP (BALP) are implicated in the abnormal skeletal mineralization and accelerated vascular calcification in chronic kidney disease (CKD) patients. Whereas ALP and BALP may predict mortality in CKD, BALP is reported to have higher sensitivity and specificity than total ALP in reflecting histological alterations in bone; however, results on their associations with bone mineral density (BMD) are inconsistent. Here we evaluated associations of total ALP and BALP with BMD during up to 24 months in end-stage renal disease (ESRD) patients. METHODS: In this longitudinal study, 194 ESRD patients (median age 57 years, 66 % male, 32 % diabetes mellitus, mean body mass index 24.8 kg/m2) underwent measurements of total ALP and BALP and total and regional body BMD (by dual-energy X-ray absorptiometry) at dialysis initiation (n = 194), and after 12 (n = 98) and 24 months (n = 40) on dialysis. RESULTS: At baseline, patients had median total ALP 65.4 (43.3-126.4) U/l, BALP 13.5 (7.1-27.3) µg/l and BMD 1.14 (0.97-1.31) g/cm2. During the study period, serum concentrations of ALP and BALP increased significantly (p < 0.001), whereas total and regional BMD remained stable. BMD correlated inversely with total ALP (rho = -0.20, p = 0.005) and BALP (rho = -0.30, p < 0.001) at baseline, and correlations were similar also at 12 and 24 months. CONCLUSION: ALP and BALP are equally accurate albeit weak predictors of BMD in ESRD patients, both at baseline and longitudinally. The dissociation between stable BMD and increasing ALP and BALP may possibly reflect increased soft tissue calcifications with time on dialysis.

Plasma Pentosidine and Its Association with Mortality in Patients with Chronic Kidney Disease.

BACKGROUND: Circulating advanced glycated end-products (AGEs) including pentosidine accumulating in chronic kidney disease (CKD) patients due to retention and increased formation are thought to contribute to cardiovascular disease (CVD). Here we evaluated factors linked to increased plasma pentosidine and its association with mortality in patients with different stages of CKD and undergoing different treatments. METHODS: Plasma pentosidine, biomarkers of inflammation, oxidative stress and nutritional status were investigated in CKD 1-2 (n = 37), CKD 3-4 (n = 54), CKD 5 non-dialyzed (CKD5-ND; n = 386), peritoneal dialysis (PD; n = 74) and hemodialysis (HD; n = 195) patients. Factors predicting plasma pentosidine were analysed by multivariate regression analysis and mortality risk was assessed by GENMOD procedure. RESULTS: Plasma pentosidine levels, which were higher in CKD5-ND, PD and HD groups than in CKD 1-2 group, were significantly lower in PD than in HD patients, and not different between PD patients and CKD5-ND patients. Pentosidine associated inversely with glomerular filtration rate (GFR), and additionally in PD with 8-hydroxy-2'-deoxyguanosine (8-OHdG), and interleukin 6 (IL-6); in HD with age, IL-6 and body mass index (BMI); in CKD5-ND with age, 8-OHdG, IL-6, high-sensitive C-reactive protein (hsCRP), and soluble vascular cell adhesion protein-1 (sVCAM-1); in CKD 3-4 with 8-OHdG and sVCAM-1; and in CKD 1-2 with age and sVCAM-1. In multivariate analysis, age (one standard deviation, 1-SD higher), malnutrition (subjective global assessment, SGA), oxidative stress (8-OHdG, 1-SD higher), and belonging to CKD5-ND, HD and PD cohorts associated with 1-SD higher pentosidine. In GENMOD, 1-SD higher pentosidine independently predicted all-cause mortality (relative risk, RR = 1.04; 95% confidence interval, CI, 1.01-1.08, p = 0.01) and CVD mortality (RR = 1.03; 95% CI, 1.01-1.06, p = 0.03) after adjusting for all confounders. CONCLUSIONS: Plasma pentosidine is markedly elevated in CKD and associates with low GFR, oxidative stress and inflammation, and is an independent predictor of mortality in CKD patients.

Elevated Circulating S100A12 Associates with Vascular Disease and Worse Clinical Outcome in Peritoneal Dialysis Patients.

UNLABELLED: ♦ BACKGROUND: The pro-inflammatory receptor of advanced glycation end-products (RAGE)-ligand S100A12 is thought to promote, whereas anti-inflammatory soluble RAGE (sRAGE) may protect against, vascular disease. We evaluated circulating S100A12 and sRAGE in relation to vascular disease, inflammation, nutritional status, and mortality risk in peritoneal dialysis (PD) patients. ♦ METHODS: Plasma S100A12 and sRAGE, biomarkers of inflammation, nutritional status, and comorbidities were analyzed in 82 prevalent PD patients (median age 65 years; 70% men; median vintage 12 months) and, for comparative analysis, also in 190 hemodialysis (HD) patients and 50 control subjects. Associations between mortality risk and concentrations of S100A12 and sRAGE were assessed in PD and HD patients after a mean follow-up period of 31 and 29 months respectively using a competing risk Cox regression model. ♦ RESULTS: In PD patients, median S100A12, sRAGE and S100A12/sRAGE were markedly higher than in controls, and S100A12 was 1.9 times higher and median sRAGE 14% lower compared with HD patients. In PD patients, S100A12 associated with C-reactive protein (ρ = 0.46; p < 0.001) and interleukin-6 (ρ = 0.38; p < 0.001), and, negatively, with s-albumin (ρ = -0.27; p < 0.05) whereas sRAGE associated negatively with body mass index (ρ = -0.37; p < 0.001), fat body mass index (ρ = -0.34; p < 0.001), and lean body mass index (ρ = -0.36; p < 0.001). Peripheral vascular disease or cerebrovascular disease (PCVD) was present in 28% of PD patients and, in multivariate analysis, associated mainly with high S100A12 (odds ratio [OR] 3.52, p = 0.04). In both PD and HD patients, the highest versus other tertiles of S100A12 associated with increased mortality. In contrast, sRAGE did not associate with PCVD or mortality in PD and HD patients. ♦ CONCLUSIONS: Plasma S100A12 and sRAGE are markedly elevated in PD patients. Soluble RAGE was inversely related to body mass indices while S100A12 associated with increased inflammation, PCVD, and mortality, suggesting that S100A12 may identify PD patients at high risk for vascular disease and increased mortality.

Autologous Peripheral Blood Mononuclear Cells as Treatment in Refractory Acute Respiratory Distress Syndrome.

BACKGROUND: Acute respiratory distress syndrome (ARDS) is a devastating disorder. Despite enormous efforts in clinical research, effective treatment options are lacking, and mortality rates remain unacceptably high. OBJECTIVES: A male patient with severe ARDS showed no clinical improvement with conventional therapies. Hence, an emergent experimental intervention was performed. METHODS: We performed intratracheal administration of autologous peripheral blood-derived mononuclear cells (PBMCs) and erythropoietin (EPO). RESULTS: We found that after 2 days of initial PBMC/EPO application, lung function improved and extracorporeal membrane oxygenation (ECMO) support was reduced. Bronchoscopy and serum inflammatory markers revealed reduced inflammation. Additionally, serum concentration of miR-449a, b, c and miR-34a, a transient upregulation of E-cadherin and associated chromatin marks in PBMCs indicated airway epithelial differentiation. Extracellular vesicles from PBMCs demonstrated anti-inflammatory capacity in a TNF-α-mediated nuclear factor-x03BA;B in vitro assay. Despite improving respiratory function, the patient died of multisystem organ failure on day 38 of ECMO treatment. CONCLUSIONS: This case report provides initial encouraging evidence to use locally instilled PBMC/EPO for treatment of severe refractory ARDS. The observed clinical improvement may partially be due to the anti-inflammatory effects of PBMC/EPO to promote tissue regeneration. Further studies are needed for more in-depth understanding of the underlying mechanisms of in vivo regeneration.

Cholinergic anti-inflammatory pathway activity in dialysis patients: a role for neuroimmunomodulation?

BACKGROUND: The cholinergic anti-inflammatory pathway (CAP) modulates inflammatory responses through the vagus nerve and the α-7-nicotinic acetylcholine receptor (α7nAChR) on macrophages and immune cells. Sympathetic/parasympathetic imbalance and chronic inflammation are both linked to poor outcome in dialysis patients. The aim of this study was to investigate CAP activity in these patients. METHODS: Twenty dialysis patients, 12 hemodialysis (HD) and 8 peritoneal dialysis (PD) patients (12 male, 8 female; age range 47-83 years) and 8 controls (5 male, 3 female; age range 31-52 years) were analyzed for C-reactive protein (CRP), tumor necrosis factor (TNF), interleukin-1b (IL-1b), IL-6 and IL-10 at baseline. The cytokines were then assessed after whole blood stimulation ex vivo with lipopolysaccharide (LPS) (10 and 100 ng/mL) and again in the presence of 45 and 90 µmol/L GTS-21, a cholinergic α7nAChR agonist. RESULTS: CRP, TNF, IL-1 and IL-6 were significantly higher, whereas IL-10 was significantly lower at baseline in patients compared with controls. After LPS stimulation, TNF increased significantly more in patients than in controls but decreased to similar levels in both groups after addition of GTS-21. IL-6 attenuation was comparable with TNF and the IL-1b pattern was similar but remained significantly higher in patients. Interestingly, IL-10 increased after GTS-21 in a dose-dependent manner, but only in patients. Results in HD and PD patients did not differ. CONCLUSIONS: The response of immune cells after LPS exposure and cholinergic stimulation suggests a functional CAP in dialysis patients. It may thus be possible to target the α7nAChR control of cytokine release as an anti-inflammatory strategy and thereby improve outcome in these patients.

Genetic, epigenetic and protein analyses of intercellular adhesion molecule 1 in Malaysian subjects with type 2 diabetes and diabetic nephropathy.

AIMS: Recent research has implicated that the inflammation may be a key pathophysiological mechanism in diabetic nephropathy (DN). Intercellular adhesion molecule 1 (ICAM-1) is an acute phase marker of inflammation. In the present study, we carried out genetic, epigenetic and protein analyses of ICAM-1 in a Malaysian population, including normal glucose tolerance (NGT) subjects and type 2 diabetes (T2D) patients with or without DN in order to evaluate its role in DN. METHODS: Analyses of DNA polymorphism and methylation in the ICAM1 gene were performed with TaqMan allelic discrimination and pyrosequencing, respectively. Plasma ICAM-1 levels were determined using an enzyme-linked immune-sorbent assay kit. RESULTS: We found that the ICAM1 K469E(A/G) polymorphism (rs5498) was significantly associated with DN. Particularly, 86.1% of T2D patients with DN carried heterozygous genotype compared to the patients without DN (68.6%). Furthermore, plasma ICAM-1 levels were increased from NGT subjects to T2D patients without and with DN (P<0.001). The NGT subjects carrying heterozygous genotype had significantly lower plasma ICAM-1 levels compared to the K469(A/A) genotype carriers (P=0.009). In the ICAM1 gene promoter, DNA methylation levels of CpG sites were low, and no association of the ICAM1 DNA methylation alteration with DN was detected. CONCLUSION: The present study provided evidence that the ICAM1 K469E(A/G) polymorphism with high heterozygous index and elevation of plasma ICAM-1 levels were associated with DN in a Malaysian population. Further prospective study of ICAM-1 protein according to the ICAM1 K469E(A/G) genotypes is necessary for predicting the susceptibility to T2D and DN.

Plasma S100A12 and soluble receptor of advanced glycation end product levels and mortality in chronic kidney disease Stage 5 patients.

BACKGROUND: Alterations in the advanced glycation end-products (AGE)-receptor of AGE (RAGE) system are linked to several chronic diseases, which may result from vascular damage. A high circulating level of the pro-inflammatory RAGE-ligand S100A12, also known as EN-RAGE, is thought to promote while a high level of soluble RAGE (sRAGE) is thought to protect against development of atherosclerotic cardiovascular disease (CVD). We evaluated circulating S100A12 and sRAGE in relation to clinical characteristics, nutritional status, inflammation and mortality risk in chronic kidney disease (CKD) Stage 5 patients starting on dialysis. METHODS: Plasma S100A12 and sRAGE, biomarkers of inflammation and nutritional status, and comorbidities were investigated in 200 CKD Stage 5 patients [median age of 56 years, 62% men and median glomerular filtration rate (GFR) of 6.2 mL/min/1.73 m(2)] in conjunction with initiation of dialysis therapy. Associations between mortality risk and S100A12 or sRAGE were assessed after a median follow-up period of 23 months. In addition, for comparative analyses, S100A12 and sRAGE levels were assessed also in 58 haemodialysis and 78 peritoneal dialysis patients after 1 year of dialysis, 56 CKD Stages 3-4 patients and 50 community-based control subjects. RESULTS: The median level of S100A12 was 4-fold higher, median sRAGE 2.4 higher and median ratio S100A12/sRAGE 2.27 times higher in CKD 5 patients than in controls. Similar alterations were observed in CKD 3-4 patients; however, CKD 5 patients had a higher median level of sRAGE than the CKD 3-4 patients. In the CKD 5 patients, S100A12 levels were higher in those with diabetes or CVD than in those without these comorbidities. Furthermore, S100A12 correlated with high-sensitivity C-reactive protein (hsCRP) levels (ρ = 0.53; P < 0.001) and a 1-SD higher level of S100A12 associated with increased all-cause mortality risk (hazard ratio 1.32, 95% confidence interval 1.01-1.73) after adjustment for age, sex, comorbidity, nutritional status and inflammation (hsCRP). In the CKD 5 patients, sRAGE correlated negatively with GFR (ρ = -0.26; P < 0.01) but sRAGE did not associate with hsCRP, comorbidities or mortality. CONCLUSIONS: Plasma concentrations of sRAGE, S100A12 and the ratio S100A12/sRAGE, are markedly elevated in CKD 5 patients starting on dialysis as well as in CKD 3-4 patients and prevalent dialysis patients suggesting that these alterations are typical for patients with moderate or severe CKD. In CKD 5 patients, an increased concentration of S100A12 are associated with inflammation, comorbidities and increased mortality risk whereas no such associations were observed for sRAGE. These results suggest that while high plasma S100A12 is an independent predictor of increased mortality risk, sRAGE does not seem to be a valid risk marker in this patient population.

Increased Levels of Modified Advanced Oxidation Protein Products Are Associated with Central and Peripheral Blood Pressure in Peritoneal Dialysis Patients.

UNLABELLED: ♦ BACKGROUND AND AIMS: Oxidative stress plays an important role in the pathogenesis of cardiovascular disease (CVD). Central blood pressure (BP) is thought to be more relevant than peripheral BP for the pathogenesis of CVD. Advanced oxidation protein products (AOPP) are markers of oxidative stress. This study investigated the relationship between AOPP and central BP in peritoneal dialysis (PD) patients. ♦ METHODS: In a cross-sectional study of 75 PD patients (67% men), we analyzed two oxidative stress markers, AOPP (modified assay, mAOPP, correcting for the impact of triglycerides) and pentosidine, three inflammation markers, interleukin-6 (IL-6), tumor necrosis factor (TNF), and high-sensitivity C-reactive protein (hs-CRP). All patients underwent measurement of central systolic blood pressure (SBP) and diastolic blood pressure (DBP) by applanation tonometry. ♦ RESULTS: Patients with mAOPP levels above the median had a higher central SBP and DBP than those below the median values. In univariate analysis, the levels of mAOPP associated with central SBP and central DBP. Multiple regression analysis, adjusting for age, gender, diabetes, CVD, protein-energy wasting (PEW), hs-CRP and extracellular water by multi-frequency bioimpedance or N-terminal prohormone of brain natriuretic peptide (NT-proBNP), confirmed independent associations between mAOPP and central SBP and central DBP respectively. ♦ CONCLUSIONS: The mAOPP level is independently associated with the central SBP and DBP in PD patients. This finding suggests that oxidative stress may be involved in the pathogenesis of hypertension or that hypertension itself or factors associated with hypertension such as fluid overload may have an additional effect on oxidative stress in PD patients.

Oxidative DNA damage and mortality in hemodialysis and peritoneal dialysis patients.

BACKGROUND AND AIMS: Increased oxidative stress in dialysis patients is thought to contribute to increased mortality; however, confirmatory data are scarce. We analyzed the serum concentration of 8-hydroxy-2'-deoxyguanosine (8-OHdG), a marker of oxidative stress, in relation to mortality in hemodialysis (HD) and peritoneal dialysis (PD) patients. METHODS: Serum 8-OHdG, interleukin 6 (IL-6), other biochemical markers, Davies comorbidity score, and protein-energy wasting (PEW) were assessed in 303 prevalent patients treated with HD (n = 220; age: 63 ± 14 years) or PD (n = 83; age: 64 ± 14 years). Mortality was assessed after a median follow-up of 31 months. RESULTS: The median (25th - 75th percentile) concentration of 8-OHdG was higher in HD than in PD patients: 1.3 ng/mL (0.9 - 1.8 ng/mL) versus 0.5 ng/mL (0.4 - 0.6 ng/mL), p < 0.001. The HD modality (standard ß = 0.57, p < 0.001) and dialysis vintage (standard ß = 0.12, p = 0.02) were independent predictors of serum 8-OHdG in a multivariable linear regression model including age, sex, body mass index, dialysis modality (HD or PD), preceding time on dialysis (dialysis vintage), PEW, comorbidity score, IL-6, and use of angiotensin converting-enzyme inhibitors or angiotensin II receptor blockers or statins. During follow-up, 107 patients died. In multivariable Cox regression models including all 303 patients and adjusted for age, sex, body mass index, dialysis modality, dialysis vintage, and comorbidity score, 8-OHdG was significantly associated with all-cause mortality (adjusted hazard ratio: 1.40; 95% confidence limits: 1.05, 1.87 for 1 standard deviation increase of 8-OHdG). In subgroup analyses according to dialysis modality, 8-OHdG was associated with mortality in HD patients but not in PD patients. CONCLUSIONS: Oxidative stress as assessed by 8-OHdG is an independent predictor of all-cause mortality in dialysis patients. This association was seen in HD patients, but no such association could be demonstrated for PD patients.

Evaluation of the association of plasma pentraxin 3 levels with type 2 diabetes and diabetic nephropathy in a Malay population.

Recent reports have demonstrated that elevated plasma long pentraxin 3 (PTX3) levels are associated with cardiovascular and chronic kidney diseases. In the current study, we investigated the plasma PTX3 levels in 296 Malay subjects including the subjects with normal glucose tolerance (NGT) and type 2 diabetes (T2DM) patients with or without DN by using an enzyme-linked immune-sorbent assay. Results showed that in males, plasma PTX3 levels in T2DM patients without DN were lower than that in the subjects with NGT (2.78 versus 3.98 ng/mL; P = 0.021). Plasma PTX3 levels in T2DM patients with DN were decreased compared to the patients without DN (1.63 versus 2.78 ng/mL; P = 0.013). In females, however, no significant alteration of plasma PTX3 levels among NGT subjects and T2DM patients with and without DN was detected. Furthermore, an inverse correlation between PTX3 and body mass index was found in male subjects with NGT (P = 0.012; r = -0.390), but not in male T2DM patients, neither in all females. The current study provided the first evidence that decreased plasma PTX3 levels are associated with T2DM and DN in Malay men and also suggested that PTX3 may have different effects in DN and chronic kidney diseases.

Metabolic changes in summer active and anuric hibernating free-ranging brown bears (Ursus arctos).

The brown bear (Ursus arctos) hibernates for 5 to 6 months each winter and during this time ingests no food or water and remains anuric and inactive. Despite these extreme conditions, bears do not develop azotemia and preserve their muscle and bone strength. To date most renal studies have been limited to small numbers of bears, often in captive environments. Sixteen free-ranging bears were darted and had blood drawn both during hibernation in winter and summer. Samples were collected for measurement of creatinine and urea, markers of inflammation, the calcium-phosphate axis, and nutritional parameters including amino acids. In winter the bear serum creatinine increased 2.5 fold despite a 2-fold decrease in urea, indicating a remarkable ability to recycle urea nitrogen during hibernation. During hibernation serum calcium remained constant despite a decrease in serum phosphate and a rise in FGF23 levels. Despite prolonged inactivity and reduced renal function, inflammation does not ensue and bears seem to have enhanced antioxidant defense mechanisms during hibernation. Nutrition parameters showed high fat stores, preserved amino acids and mild hyperglycemia during hibernation. While total, essential, non-essential and branched chain amino acids concentrations do not change during hibernation anorexia, changes in individual amino acids ornithine, citrulline and arginine indicate an active, although reduced urea cycle and nitrogen recycling to proteins. Serum uric acid and serum fructose levels were elevated in summer and changes between seasons were positively correlated. Further studies to understand how bears can prevent the development of uremia despite minimal renal function during hibernation could provide new therapeutic avenues for the treatment of human kidney disease.

Circulating vascular endothelial growth factor (VEGF) and its soluble receptor 1 (sVEGFR-1) are associated with inflammation and mortality in incident dialysis patients.

BACKGROUND: Vascular endothelial growth factor (VEGF) and its soluble receptor 1 (sVEGFR-1) predict mortality in nondialyzed chronic kidney disease (CKD) stage 3-5 patients and prevalent hemodialysis (HD) patients. We investigated determinants of VEGF and sVEGFR-1 as well as their relationship with all-cause mortality in incident dialysis patients. METHODS: In this longitudinal cohort study of 211 CKD 5 patients [64% males, mean age of 54 ± 12 years and median glomerular filtration rate (GFR) 5.9 [interquartile range (IQR), 4.6-7.2 mL/min/1.73 m2] who were enrolled at initiation of renal replacement therapy, demographics, clinical characteristics, including comorbidities and laboratory data were obtained at the beginning of the study. After 12 months, blood was again drawn from 95 dialysis patients [42 HD patients and 53 peritoneal dialysis (PD) patients]. The 211 patients were followed up for a median of 29 (IQR, 15-37) months for survival analysis. Plasma was also obtained from 47 healthy controls. RESULTS: VEGF and sVEGFR-1 levels did not change significantly after 12 months on HD or PD. The sVEGFR-1, but not VEGF levels, differed between the patients and the healthy controls. VEGF and sVEGFR-1 correlated with high-sensitivity C-reactive protein (hsCRP; rho = 0.19, P = 0.01 and rho = 0.16, P = 0.03; respectively), leukocyte count (rho = 0.22; P < 0.01 and rho = 0.23; P < 0.01; respectively) and sVEGFR-1 correlated also with interleukin-6 (IL-6) (rho = 0.21, P < 0.01). In Kaplan-Meier analysis, a high VEGF level was associated with increased all-cause mortality (Chi-square = 5.8, P = 0.02) which remained after adjustments for age, gender, body mass index (BMI), IL-6, GFR and comorbidities [hazard ratio, HR: 3.08, 95% confidence intervals (CI) 1.48-6.42]. Whereas sVEGFR-1 per se did not predict mortality, a high sVEGFR-1 level in patients with concomitant high IL-6 was associated with increased all-cause mortality (HR 2.83, 95% CI 1.32-6.06) which remained significant after adjustments for age, gender, BMI and comorbidities (HR 2.33, 95% CI 1.06-5.14) but not after adjusting also for GFR. CONCLUSIONS: The circulating levels of VEGF and sVEGFR-1 are associated with biomarkers of inflammation. VEGF predicts all-cause mortality, independent of inflammation, while an elevated sVEGFR-1 level increased the mortality risk in inflamed patients.