Serum soluble Fas (CD95) and Fas ligand profiles in chronic kidney failure

Induction of Vesicular Trafficking and JNK-Mediated Apoptotic Signaling in Mononuclear Leukocytes Marks the Immuno-Proteostasis Response to Uremic Proteins

INTRODUCTION

Uremic retention solutes have been alleged to induce the apoptotic program of different cell types, including peripheral blood mononuclear leukocytes (PBL), which may contribute to uremic leukopenia and immune dysfunction.

METHODS

The molecular effects of these solutes were investigated in uremic PBL (u-PBL) and mononuclear cell lines (THP-1 and K562) exposed to the high molecular weight fraction of uremic plasma (u-HMW) prepared by in vitro ultrafiltration with 50 kDa cut-off microconcentrators.

RESULTS

u-PBL show reduced cell viability and increased apoptotic death compared to healthy control PBL (c-PBL). u-HMW induce apoptosis both in u-PBL and c-PBL, as well as in mononuclear cell lines, also stimulating cellular H2O2 formation and secretion, IRE1-α-mediated endoplasmic reticulum stress signaling, and JNK/cJun pathway activation. Also, u-HMW induce autophagy in THP-1 monocytes. u-PBL were characterized by the presence in their cellular proteome of the main proteins and carbonylation targets of u-HMW, namely albumin, transferrin, and fibrinogen, and by the increased expression of receptor for advanced glycation end-products, a scavenger receptor with promiscuous ligand binding properties involved in leukocyte activation and endocytosis.

CONCLUSIONS

Large uremic solutes induce abnormal endocytosis and terminal alteration of cellular proteostasis mechanisms in PBL, including UPR/ER stress response and autophagy, ultimately activating the JNK-mediated apoptotic signaling of these cells. These findings describe the suicidal role of immune cells in facing systemic proteostasis alterations of kidney disease patients, a process that we define as the immuno-proteostasis response of uremia.

Baseline Ratio of Soluble Fas/FasL Predicts Onset of Pulmonary Hypertension in Elder Patients Undergoing Maintenance Hemodialysis: A Prospective Cohort Study

Background

Pulmonary hypertension (PH) is one of the most common complications associated with end-stage renal disease (ESRD). Though numerous risk factors have been founded, other risk factors remain unidentified, particularly in patients undergoing maintenance hemodialysis with elder age. Soluble Fas (sFas) and its ligand FasL (sFasL) have been reported in chronic renal disease patients; however, they have not been identified in the PH patients of elder hemodialysis patients. We aimed to determine the roles of sFas/sFasL in onset of PH in elder patients undergoing maintenance hemodialysis with ESRD.

Methods

Altogether, 163 patients aged 68.00 ± 10.51 years with ESRD who undergoing maintenance hemodialysis in a prospective cohort and were followed-up for a median of 5.5 years. They underwent echocardiography examinations, liver function assessments, residual renal function, and serum ion examinations, before and after dialysis. Furthermore, levels of sFas and sFasL at baseline had also been measured. We compared demographic data, echocardiographic parameters, liver function, ions, and residual renal function as well as serum sFas and sFasL between the PH and non-PH groups. These parameters were correlated with systolic pulmonary artery pressure (sPAP) using Spearman’s correlation. Moreover, univariate and adjusted logistic regression analyses have also been conducted.

Results

The incidence of PH in the elder dialysis patients was 39.1%. PH populations were demonstrated with significantly higher end-diastolic internal diameters of the left atrium, left ventricle, right ventricle (RV), and pulmonary artery, as well as the left ventricular posterior wall thickness (LVWP; all p < 0.05). A higher baseline serum sFas and sFasL levels have also been identified ( p < 0.001). They also showed lower fractional shortening and left ventricular ejection fraction (LVEF; p < 0.05). Following dialysis, the post-dialysis serum potassium concentration (K⁺) was significantly higher in the PH group ( p = 0.013). Furthermore, the adjusted regression identified that ratio of sFas/FasL (OR: 1.587, p = 0.004), RV (OR: 1.184, p = 0.014), LVPW (OR: 1.517, p = 0.007), and post-dialysis K⁺ (OR: 2.717, p = 0.040) was the independent risk factors for PH while LVEF (OR: 0.875, p = 0.040) protects patients from PH.

Conclusion

The baseline ratio of sFas/sFasL, RV, LVPW, and post-dialysis K⁺ was independent risk factors for PH onset, while LVEF was a protective factor for PH.

High Serum Levels of Soluble Fas (sFas) in Ckd Patients: Effects of Renal Clearance, Reabsorption and Synthesis

Purpose

Increased serum concentrations of soluble Fas (sFas) have been reported in patients with chronic kidney disease (CKD). However, little is known about the renal clearance of sFas, whether sFas is reabsorbed in the renal tubules, or the behavior of sFas synthesis in CKD.

Materials and Methods

We studied 69 patients with CKD (60±15 years old, creatinine clearance 37+19 ml/min/1.73 m2) and 14 healthy subjects (61±17 years, creatinine clearance 79±24 ml/min/1.73 m2). ELISA was used to measure the levels of sFas (pg/mL) and retinol binding protein (RBP - mg/L). RT-PCR was used to quantify sFasmRNA of leukocytes.

Results

Serum sFas levels were significantly higher in patients with CKD (2781±1214 vs. 2196±773, p=0.02). The concentrations of sFas in 24-hour urine samples (23±27 vs. 40±17, p=0.006) and sFas Clearance (0.019±0.022 vs. 0.036±0.020, p=0.01) were significantly lower in patients with CKD. sFas clearance correlated with creatinine clearance (r=0.25, p=0.02). Urine concentrations of RBP correlated with sFas concentrations in the urine (r=0.80, p<0.001). sFasmRNA were higher in patients with CKD (3.9±1.8 vs. 2.5±0.9, p<0.001).

Conclusions

In CKD patients, the decrease in renal function is followed by a decrease in sFas clearance and an increase in serum sFas. In patients with proximal tubule dysfunction (high urinary RBP concentrations), urinary sFas is also increased, suggesting that sFas is reabsorbed by the proximal tubule. It is possible that an increase in sFas synthesis also contributes to the increase of serum sFas concentrations in uremia.

Circulating levels of soluble Fas (sCD95) are associated with risk for development of a nonresolving acute kidney injury subphenotype

Background

Critically ill patients with acute kidney injury (AKI) can be divided into two subphenotypes, resolving or nonresolving, on the basis of the trajectory of serum creatinine. It is unknown if the biology underlying these two AKI recovery patterns is different.

Methods

We measured eight circulating biomarkers in plasma obtained from a cohort of patients admitted to an intensive care unit (ICU) (n = 1241) with systemic inflammatory response syndrome. The biomarkers were representative of several biologic processes: apoptosis (soluble Fas), inflammation (soluble tumor necrosis factor receptor 1, interleukin 6, interleukin 8) and endothelial dysfunction, (angiopoietin 1, angiopoietin 2, and soluble vascular cell adhesion molecule 1). We tested for associations between biomarker levels and AKI subphenotypes using relative risk regression accounting for multiple hypotheses with the Bonferroni correction.

Results

During the first 3 days of ICU admission, 868 (70%) subjects developed AKI; 502 (40%) had a resolving subphenotype, and 366 (29%) had a nonresolving subphenotype. Hospital mortality was 12% in the resolving subphenotype and 21% in the nonresolving subphenotype. Soluble Fas was the only biomarker associated with a nonresolving subphenotype after adjustment for age, body mass index, diabetes, and Acute Physiology and Chronic Health Evaluation III score (p = 0.005).

Conclusions

Identifying modifiable targets in the Fas-mediated pathway may lead to strategies for prevention and treatment of a clinically important form of AKI.

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-017-1807-x) contains supplementary material, which is available to authorized users.

Normoalbuminuric diabetic kidney disease

Diabetic kidney disease (DKD) is one of the primary causes of end-stage renal disease (ESRD). Early diagnosis is very important in preventing the development of DKD. Urinary albumin excretion rate (UAER) and glomerular filtration rate (GFR) are widely accepted as criteria for the diagnosis and clinical grading of DKD, and microalbuminuria has been recommended as the first clinical sign of DKD. The natural history of DKD has been divided into three stages: normoalbuminuria, microalbuminuria, and macroalbuminuria. However, this clinical paradigm has been questioned recently, as studies have shown that a portion of diabetes mellitus (DM) patients with normoalbuminuria have progressive renal insufficiency, referred to as normoalbuminuric diabetic kidney disease (NADKD) or nonalbuminuric diabetic nephropathy. Epidemiologic research has demonstrated that normoalbuminuric diabetic kidney disease is common, and the large number of NADKD patients suggests that the traditional paradigm needs to be shifted. Currently, the pathogenesis of NADKD remains unclear, but many clinical studies have identified some clinical and pathological features of NADKD. In addition, the long-term outcomes of NADKD patients remain controversial. In this article, we reviewed the latest studies addressing the pathogenesis, pathology, treatment and prevention of NADKD.

Serum Soluble-Fas, Inflammation, and Anemia in Acute Kidney Injury

Anemia is a common feature in critically ill patients. Serum soluble-Fas (sFas) levels are associated with anemia in chronic kidney disease. It is possible that sFas levels are also associated with anemia in acute kidney injury (AKI) patients. The study aims to investigate the relationship between serum levels of sFas, erythropoietin (Epo), inflammatory cytokines, and hemoglobin (Hb) concentration in critically ill patients with AKI. We studied 72 critically ill patients with AKI (AKI group; n = 53) or without AKI (non-AKI group; n = 19), and 18 healthy volunteers. Serum sFas, Epo, tumor necrosis factor-alpha (TNF-α), interleukin (IL)-6, IL-10, iron status, and Hb concentration were analyzed in all groups. We also investigated the correlation between these variables in the AKI group. Critically ill patients (AKI and non-AKI groups) had higher serum levels of Epo than healthy volunteers. Hb concentration was lower in the AKI group than in the other groups. Serum sFas, IL-6, TNF-α, and ferritin levels were higher in the AKI group. Hb concentration correlated negatively with serum IL-6 (r = -0.37, P = 0.008), sFas (r = -0.35, P = 0.01), and Epo (r = -0.27, P = 0.04), while serum sFas correlated positively with iron levels (r = 0.36, P = 0.008) and IL-6 (r = 0.28, P = 0.04) in the AKI group. In multivariate analysis, after adjusting for markers of inflammation and iron stores, only serum sFas levels (P = 0.03) correlated negatively with Hb concentration in the AKI group. Serum Epo and inflammatory cytokine levels are elevated in critically ill patients with or without AKI. Serum levels of sFas are elevated and independently associated with anemia in critically ill patients with AKI.

Mononuclear leukocyte apoptosis and inflammatory markers in patients with chronic kidney disease

BACKGROUND/AIM

Increased apoptosis along with enhanced inflammation has been reported in hemodialysis and pre-dialysis patients. However, there is limited information at which stage during the progression of chronic kidney disease (CKD) the balance between pro- and anti-apoptotic mechanisms is disturbed and inflammatory response is activated. The aim of this study was to investigate possible alterations in apoptotic and inflammatory markers during CKD (stages 1-4) progression and the probable interactions between them.

METHODS

In a cross-sectional study, 152 steady-state CKD outpatients (83 males, 55%) with mean estimated glomerular filtration rate 46 (29-76) ml/min/1.73 m(2) were studied. Apoptosis was assessed in peripheral blood mononuclear cells by estimating Bcl-2 expression, annexin V-propidium iodine staining and serum soluble Fas (sFas) and Fas-ligand. Serum levels of C-reactive protein, tumor necrosis factor-α (TNF-α), interleukin-6 and plasma levels of fibrinogen were measured as markers of inflammation.

RESULTS

Bcl-2 expression was found to decrease significantly in both lymphocytes and monocytes from CKD stage 1 to 4. In contrast, the activity of sFas increased significantly and so did the levels of TNF-α and fibrinogen. The majority of these alterations occurred as soon as patients entered stage 3 of CKD. A multivariate regression analysis demonstrated that CKD remained a significant predictor of the aggregate of the assessed markers.

CONCLUSIONS

Apoptosis appeared to increase across CKD stages 1-4, and this was associated with increased proinflammatory activity.

The sFas/sFasL ratio as a novel marker of inflammation in children with chronic kidney disease

OBJECTIVES

Membrane Fas-FasL binding triggers apoptosis, enhanced in chronic kidney disease (CKD). However, the role of soluble forms, sFas and sFasL, remains unclear. Matrix metalloproteinases (MMPs) are known converters of sFasL from the membrane-bound form, but there are no data on relations between sFas/sFasL, MMPs, their tissue inhibitors (TIMPs) or inflammatory/endothelial factors in CKD patients. We aimed to evaluate correlations between sFas, sFasL, MMP-2, MMP-7, MMP-9, TIMP-1, TIMP-2, and the role of sFas/sFasL as markers of inflammation and endothelial dysfunction.

METHODS

Serum concentrations of sFas, sFasL, MMPs, TIMPs, hsCRP, IL-4 and sE-selectin were assessed by ELISA in 65 CKD children and in 30 controls.

RESULTS

sFas, sFasL, sFas/sFasL ratio, MMPs, TIMPs, sE-selectin and IL-4 levels were significantly enhanced in CKD patients vs. controls. sFas/sFasL ratio correlated with inflammatory/endothelial markers. sE-selectin was the best predictor of sFas and sFas/sFasL ratio. MMP-9, TIMP-1 and IL-4 predicted most accurately the sFasL concentrations.

CONCLUSIONS

CKD children present with progressive sFas/sFasL dysfunction. Relations between sFas/sFasL, MMPs and TIMPs indicate the potential role of metalloproteinases in the sFas/sFasL regulation. Correlations with hsCRP, sE-selectin and IL-4 suggest that sFas/sFasL ratio may become a new marker of inflammation and endothelial dysfunction in children with CKD.

Montelukast abrogates rhabdomyolysis-induced acute renal failure via rectifying detrimental changes in antioxidant profile and systemic cytokines and apoptotic factors production

In addition to antiasthmatic effect, the cysteinyl leukotriene receptor 1 (CysLT₁) antagonist montelukast shows renoprotective effect during ischemia/reperfusion and cyclosporine-induced renal damage. Here, we proposed that montelukast protects against rhabdomyolysis-induced acute renal failure. Compared with saline-treated rats, at 48 h following the induction of rhabdomyolysis using intramuscular glycerol (10 ml 50% glycerol/kg), significant elevations in serum levels of urea, creatinine, phosphate and acute renal tubular necrosis were observed. This was associated with elevations in serum Fas, interleukin-10, tumor necrotic factor-alpha, and transforming growth factor-beta1 and renal malondialdehyde and nitrite and detrimental reductions in renal catalase and superoxide dismutase activities. The effects of rhabdomyolysis on renal functional, biochemical and structural integrity and the associated changes in cytokines and Fas levels were abolished upon concurrent administration of montelukast (10 mg/kg i.p.) for 3 days (1 day before and 2 days after induction of rhabdomyolysis). Alternatively, administration of the anti-oxidant, α-tocopherol (400 mg/kg i.m.) for 3 days, succeeded in alleviating renal oxidative stress, but had no significant effect on the circulating levels of most cytokines and partially restored kidney functional and structural damage. Serum level of interleukin-6 was not altered by rhabdomyolysis but showed significant elevations in rats treated with montelukast or α-tocopherol. Collectively, motelukast abrogated functional and structural renal damage induced by rhabdomyolysis via ameliorating renal oxidative stress and modulation of systemic cytokines and apoptotic factors production. The results of this work are expected to open new avenues for early prevention of rhabdomyolysis-induced acute renal failure using selective CysLT₁ antagonists such as montelukast.

Chronic kidney disease worsens sepsis and sepsis-induced acute kidney injury by releasing High Mobility Group Box Protein-1

We have shown that folate-induced kidney dysfunction and interstitial fibrosis predisposes mice to sepsis mortality. Agents that increase survival in normal septic mice were ineffective in a two-stage kidney disease model. Here we used the 5/6 nephrectomy mouse model of progressive chronic kidney disease (CKD) to study how CKD affects acute kidney injury (AKI) induced by sepsis. We induced sepsis using cecal ligation and puncture and found that the presence of CKD intensified the severity of kidney and liver injury, cytokine release, and splenic apoptosis. Accumulation of High Mobility Group Box Protein-1 (HMGB1; a late proinflammatory cytokine released from apoptotic cells), vascular endothelial growth factor (VEGF), tumor necrosis factor (TNF)-α, interleukin (IL)-6, or IL-10 was increased in CKD or sepsis alone and to a greater extent in CKD-sepsis. Only part of the increase was explained by decreased renal clearance. Surprisingly, we found splenic apoptosis in CKD, even in the absence of sepsis. Although VEGF neutralization with soluble fms-like tyrosine kinase 1 (sFLT-1) (a soluble VEGF receptor) effectively treated sepsis, it was ineffective against CKD-sepsis. A single dose of HMGB1-neutralizing antiserum administered 6 h after sepsis alone was ineffective; however, CKD-sepsis was attenuated by anti-HMGB1. Splenectomy transiently decreased circulating HMGB1 levels, reversing the effectiveness of anti-HMGB1 treatment on CKD-sepsis. Thus, progressive CKD increases the severity of sepsis, in part, by reducing the renal clearance of several cytokines. CKD-induced splenic apoptosis and HMGB1 release could be important common mediators for both CKD and sepsis.

Matrix metalloproteinases and soluble Fas/FasL system as novel regulators of apoptosis in children and young adults on chronic dialysis

The system of membrane receptor Fas and its ligand FasL compose one of the main pathways triggering apoptosis. However, the role of their soluble forms has not been clarified yet. Although sFasL can be converted from the membrane-bound form by matrix metalloproteinases (MMPs), there are no data on relations between sFas/sFasL, MMPs and their tissue inhibitors (TIMPs) in patients on chronic dialysis—neither children nor adults. The aim of our study was to evaluate serum concentrations of sFas, sFasL, and their potential regulators (MMP-2, MMP-7, MMP-9, TIMP-1, TIMP-2), in children and young adults chronically dialyzed. Twenty-two children on automated peritoneal dialysis (APD), 19 patients on hemodialysis (HD) and 30 controls were examined. Serum concentrations of sFas, sFasL, MMPs and TIMPs were assessed by ELISA. Median values of sFas, sFasL, sFas/sFasL ratio, MMP-2, MMP-7, MMP-9, TIMP-1 and TIMP-2 were significantly elevated in all dialyzed patients vs. controls, the highest values being observed in subjects on HD. A single HD session caused the decrease in values of all parameters to the levels below those seen in children on APD. Regression analysis revealed that MMP-7 and TIMP-1 were the best predictors of sFas and sFasL concentrations. Children and young adults on chronic dialysis are prone to sFas/sFasL system dysfunction, more pronounced in patients on hemodialysis. The correlations between sFas/sFasL and examined enzymes suggest that MMPs and TIMPs take part in the regulation of cell death in the pediatric population on chronic dialysis, triggering both anti- (sFas) and pro-apoptotic (sFasL) mechanisms.

Serum concentrations of markers of TNFalpha and Fas-mediated pathways and renal function in nonproteinuric patients with type 1 diabetes

BACKGROUND AND OBJECTIVES

The aim of our study was to examine serum markers of the TNF and Fas pathways for association with cystatin-C based estimated glomerular filtration rate (cC-GFR) in subjects with type 1 diabetes (T1DM) and no proteinuria.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

The study group (the 2nd Joslin Kidney Study) comprised patients with T1DM and normoalbuminuria (NA) (n = 363) or microalbuminuria (MA) (n = 304). Impaired renal function (cC-GFR <90 ml/min) was present in only 10% of patients with NA and 36% of those with MA. We measured markers of the tumor necrosis factor alpha (TNFalpha) pathway [TNFalpha, soluble TNF receptor 1 (sTNFR1), and 2 (sTNFR2)], its downstream effectors [soluble intercellular and soluble vascular adhesion molecules (sICAM-1 and sVCAM-1), interleukin 8 (IL8/CXCL8), monocytes chemoattractant protein-1 (MCP1), and IFNgamma inducible protein-10 (IP10/CXCL10)], the Fas pathway [soluble Fas (sFas) and Fas ligand (sFasL)], CRP, and IL6.

RESULTS

Of these, TNFalpha, sTNFRs, sFas, sICAM-1, and sIP10 were associated with cC-GFR. However, only the TNF receptors and sFas were associated with cC-GFR in multivariate analysis. Variation in the concentration of the TNF receptors had a much stronger impact on GFR than clinical covariates such as age and albumin excretion.

CONCLUSIONS

Elevated concentrations of serum markers of the TNFalpha and Fas-pathways are strongly associated with decreased renal function in nonproteinuric type 1 diabetic patients. These effects are independent of those of urinary albumin excretion. Follow-up studies are needed to characterize the role of these markers in early progressive renal function decline.

Serum levels of soluble Fas, nitric oxide and cytokines in acute decompensated cirrhotic patients

AIM: To evaluate plasma levels of nitrite/nitrate (NOx), soluble Fas (sFas) antigen, tumor necrosis factor alpha (TNF-α) and interleukin-6 (IL-6) in patients with compensated and acute decompensated cirrhosis and to evaluate mediators causing acute decompensation in liver cirrhosis.

METHODS: This prospective study was conducted in the medical intensive care unit of an academic tertiary center. Fifty-five patients with acute decompensation (gastrointestinal hemorrhage, encephalopathy, hydropic decompensation) and twenty-five patients with compensated liver cirrhosis were included. Blood samples were taken for analyses of sFas, Nox, IL-6, TNF-α. Liver enzymes and kidney functions were also tested.

RESULTS: In patients with acute decompensation, plasma sFas levels were higher than in non-decompensated patients (15 305 ± 4646 vs 12 458 ± 4322 pg/mL, P < 0.05). This was also true for the subgroup of patients with alcoholic liver cirrhosis (P < 0.05). The other mediators were not different and none of the parameters predicted survival, except for ALT (alanine-aminotransferase). In patients with portal-hypertension-induced acute hemorrhage, NOx levels were significantly lower than in patients with other forms of decompensation (70.8 ± 48.3 vs 112.9 ± 74.9 pg/mL, P < 0.05). When NOx levels were normalized to creatinine levels, the difference disappeared. IL-6, TNF-α and sFas were not different between bleeders and non-bleeders. In decompensated patients sFas, IL-6 and NOx levels correlated positively with creatinine levels, while IL-6 levels were dependent on Child class.

CONCLUSION: In acute decompensated cirrhotic patients sFas is increased, suggesting a role of apoptosis in this process and patients with acute bleeding have lower NOx levels. However, in this acute complex clinical situation, kidney function seems to have a predominant influence on mediator levels.

Correlation between increased serum sFas levels and microalbuminuria in type 1 diabetic patients

OBJECTIVE

The aim of this study was to elucidate if apoptosis dysregulation is present in type 1 diabetic patients with microalbuminuria.

SUBJECTS AND METHODS

The following variables were determined in 29 type 1 diabetic patients: the duration of diabetes, soluble Fas (sFas), Bcl-2, hemoglobin A(1c) levels, glomerular filtration rate (GFR) and microalbuminuria, using the urine albumin to urine creatinine ratio (ACR). Age and gender were assessed and patients were categorized into two groups, according to their ACR: the microalbuminuric (MA) group with an ACR > or =30 mg/g, and the normoalbuminuric (NA) group with an ACR <30 mg/g.

RESULTS

The differences between the two groups regarding sFas, Bcl-2 and GFR were not statistically significant. However, in the MA group, a significant positive relationship between sFas and ACR was observed (r = 0.736, p = 0.015). Dividing patients into two subgroups--mild versus severe (ACR > or =150 mg/g) microalbuminuric patients--significant differences in sFas (60.4 vs. 87.2 pg/ml; p = 0.047) and GFR (113 vs. 69.5 ml min(-1) 1.73 m(-2); p = 0.021) were observed, whereas in Bcl-2, the difference was not significant (77.96 vs. 71.13 ng/ml).

CONCLUSIONS

At the early stages of diabetic nephropathy in type 1 diabetic patients, there seems to be a dysregulation of apoptosis, as expressed by enhanced sFas levels, leading to the speculation that the prevalence of antiapoptotic mechanisms (sFas) may promote mesangial proliferation.

The impact of traditional and non-traditional risk factors on coronary calcification in pre-dialysis patients

BACKGROUND

Coronary heart disease (CHD) is the leading cause of death among end-stage renal disease patients. There is evidence that coronary calcification is a marker of atherosclerotic vascular disease and is predictive of cardiovascular events, especially in patients on renal replacement therapy. It has recently been suggested that CHD begins in the pre-dialysis period. However, data regarding coronary calcification in this population is scarce. This study was aimed at evaluating such coronary calcification and identifying related factors.

METHODS

A total of 96 chronic kidney disease out-patients who were not on dialysis were included. Patients presenting neoplastic, infectious or inflammatory diseases were excluded. Demographic characteristics, clinical profiles, laboratory test results and multislice computed tomography scans were evaluated.

RESULTS

The median age was 55 years (range 20-69 years), 67% were men and the median creatinine clearance was 37 ml/min/1.73 m(2). Coronary calcification, defined as a coronary artery calcification score (CACS) >0 Agatston units (AU), was seen in 61 patients (median 89.1 AU, range 0.37-2299.3 AU). On average, these patients were older, more often had diabetes, higher body mass indices and higher Framingham risk indices, as well as presenting higher proteinuria, intact parathyroid hormone (iPTH), blood glucose and triglyceride levels compared with those without calcification. Multiple logistic regression analysis, adjusted for age and diabetes, identified iPTH and triglyceride levels as independent determinants of calcification. Severe calcification (CACS >400 AU) was seen in 22 patients, who were also older and more frequently had a history of cardiovascular disease (CVD), as well as having higher levels of phosphorus, blood glucose and soluble Fas (sFas). Multiple logistic regression analysis, adjusted for age and diabetes, identified phosphorus and sFas levels as independent determinants of severe coronary calcification.

CONCLUSION

Coronary calcification is highly prevalent in pre-dialysis patients and correlates with traditional and non-traditional risk factors for CVD.

Coronary artery calcification, systemic inflammation markers and mineral metabolism in a peritoneal dialysis population

AIMS

To assess the prevalence of coronary artery calcification (CAC) in peritoneal dialysis (PD) patients and to determine whether comorbidities such as inflammation, dyslipidemia and mineral metabolism disorders correlate with its development.

METHODS

Forty-nine PD patients (45% male; median age, 52 years) were submitted to multislice computed tomography. Inflammatory markers, anti-oxidized LDL antibody, calcium-phosphate balance and lipid profiles were assessed.

RESULTS

Twenty-nine patients (59.2%) presented CAC (median calcium score, 234.7 Agatston units). Patients with CAC were older than those without, more frequently presented a history of coronary artery disease or hypertension and had lower HDL cholesterol levels, as well as presenting higher levels of osteoprotegerin and LDL oxidation. The logistic regression revealed that the independent determinants of CAC were age (odds ratio = 1.12; p = 0.006) and number of prescribed anti-hypertensive drugs (odds ratio = 2.38; p = 0.048). When the population was stratified by calcium score quartile, soluble Fas levels were significantly higher in patients with severe calcification. In patients younger than 45, CAC correlated positively with phosphorus levels (r = 0.52; p = 0.04).

CONCLUSION

In PD patients, CAC is highly prevalent. Our results indicate that conditions such as inflammation and mineral disturbances are associated with its development.

Soluble Fas—A promising novel urinary marker for the detection of recurrent superficial bladder cancer

BACKGROUND

The objective of this study was to test the hypothesis that elevated urinary levels of soluble Fas (sFas) would aid in the surveillance of patients with a past history of nonmuscle-invasive transitional cell carcinoma (TCC) of the urinary bladder.

METHODS

sFas levels were determined in cell lysates and supernatants from 2 human bladder cancer cell lines (T24 and TCC-SUP) and in voided urine from 188 consecutive patients who were at risk for TCC recurrence, 31 patients who had noncancerous urologic conditions, and 10 healthy individuals. The authors also obtained barbotage cytology and voided nuclear matrix protein 22 (NMP22) levels. sFas was analyzed continuously and categorically on the basis of its quintile distribution.

RESULTS

sFas was present in cell lysates and conditioned media from both cell lines. sFas levels were found to be higher in the TCC group (n = 122 patients) compared with the control group (P < .001). Higher levels of sFas were associated with positive cytology assay results (P < .001), higher NMP22 levels (P < .001), NMP22 levels > 10 U/mL (P < .001), and tumor stage > or = T1 (P < .001). The areas under the receiver operating characteristics (ROC) curves of sFas and NMP22 for bladder cancer detection were 0.757 (95% confidence interval, 0.694-0.819) and 0.704 (95% confidence interval, 0.637-0.772), respectively. In the > 75% sensitivity region of the ROC curves, sFas was consistently more specific than NMP22. In multivariate analyses, sFas, NMP22, and cytology all were found to be associated with the presence of bladder cancer (P values < or = .009), but only sFas and cytology were associated with tumor stage > or = T1 (P values < or = .026).

CONCLUSIONS

sFas was produced and released by bladder TCC cells. Urine sFas was an independent predictor of bladder cancer recurrence and invasiveness in patients who had a past history of nonmuscle invasive bladder TCC, and it outperformed NMP22.

Associations of Fas (CD95), tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL), and biochemical manifestations in elderly persons

BACKGROUND

This study investigated the relationships of soluble Fas (CD95) and tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) vs. biochemical manifestations.

METHODS

Serum concentrations of soluble Fas, TRAIL, and biochemical parameters were measured in 171 healthy adults.

RESULTS

There were no significant age- and gender-related differences in Fas and TRAIL concentrations. However, aspartate and alanine aminotransferase and gamma-glutamyl transferase (AST, ALT, and GGT) activities were significantly higher in men with Fas > or =429.5 and TRAIL > or =63.2 pg/ml than in those with Fas <429.5 and TRAIL <63.2 pg/ml (26.8+/-10.9, 33.2+/-14.6, and 79.2+/-46.9 IU/l vs. 17.6+/-4.6, 20.4+/-7.8, and 35.3+/-21.3 IU/l, p<0.05, respectively). Serum triglyceride, total protein, and uric acid concentrations averaged 172.8+/-58.4 mg/dl, 7.8+/-0.3 g/dl, and 4.8+/-1.1 mg/dl in women with Fas > or =352.1 and TRAIL > or =64.9 pg/ml, which were significantly above the values of those with Fas <352.1 and TRAIL <64.9 pg/ml (116.9+/-49.2 mg/dl, 7.4+/-0.3 g/dl, and 3.7+/-0.7 mg/dl, p<0.05, respectively). Serum soluble Fas concentrations correlated significantly with AST (r=0.36, p<0.05), ALT (r=0.30, p<0.05), and GGT (r=0.29, p<0.05) in men and triglyceride (r=0.34, p<0.05), protein (r=0.27, p<0.05), and uric acid levels (r=0.41, p<0.05) in women.

CONCLUSION

Apoptotic activity seems to have an important relationship to biochemical parameters, especially hepatic enzymes, total protein, triglyceride, and uric acid in elderly persons.

Expression of TNF-related apoptosis-inducing ligand (TRAIL) in megakaryocytes and platelets

OBJECTIVE

Platelets are known to play an important role in hemostasis, thrombosis, wound healing, and inflammation. Platelet-induced modulation of inflammation and adaptive immune responses are mediated in part through tumor necrosis factor (TNF) family member ligands, including CD154, Fas ligand, and TNFalpha, that are expressed upon platelet activation. The present study investigated whether platelets and megakaryocytes also express TNF-related apoptosis-inducing ligand (TRAIL), another pro-apoptotic member of the TNF superfamily.

MATERIALS AND METHODS

Immunoprecipitation, enzyme-linked immunosorbent assay, and flow cytometry were used to assess TRAIL protein expression on isolated platelets, in vitro-derived megakaryocytes and premegakaryocyte cell lines. Reverse-transcription polymerase chain reaction and transient transfection of TRAIL promoter/reporter constructs were used to elucidate mechanisms of TRAIL regulation during megakaryocyte differentiation. TRAIL-dependent cytotoxicity assays were performed to determine if platelet-derived TRAIL induces apoptosis of TRAIL sensitive target cells.

RESULTS

Activated platelets expressed both membrane-bound and soluble TRAIL. TRAIL was also expressed by megakaryocytes, and in vitro studies showed that TRAIL expression was induced upon megakaryocyte differentiation. TRAIL expression was mediated by increased transcriptional activity of the TRAIL promoter, suggesting lineage-specific regulation of TRAIL during megakaryocyte differentiation. Abundant detergent-extractable, full-length TRAIL protein was observed in the lysates of platelets and megakaryocytes, but only low concentrations of TRAIL were released by nondetergent extraction methods.

CONCLUSION

The data reported herein show that platelets express TRAIL that is synthesized by megakaryocytes and was expressed by activated platelets. While these data expand the spectrum of TNF family proteins expressed in platelets, the function of platelet-derived TRAIL is not known.

Involvement of apoptosis in patients with diabetic nephropathy: A study on plasma soluble Fas levels and pathological findings

AIMS

We investigated the relationship between levels of plasma soluble Fas (sFas) and stages of diabetic nephropathy, with special reference to apoptosis and clinical features of diabetic nephropathy in 168 patients with diabetic nephropathy.

RESULTS

There was a positive correlation between plasma sFas and creatinine levels, between sFas levels and urinary protein levels, and between sFas levels and urinary albumin. There was a negative correlation between plasma sFas levels and creatinine clearance. Plasma sFas levels in the early stage (stages 1, 2, 3A) and advanced stage (stages 3B and 4) were 2.6 +/- 0.1 and 5.4 +/- 0.5 ng/mL, respectively. Plasma sFas level of the advanced stage was significantly higher than that of the early stage. The number of proliferating cell nuclear antigen (PCNA) positive cells was significantly lower in the advanced stage than in the early stage. The number of in situ nick-end labelling (TUNEL) positive cells was also significantly lower in the advanced stage than in the early stage, suggesting the suppression of apoptosis.

CONCLUSION

These data suggest that apoptosis is involved in the advancement of diabetic nephropathy, and that plasma sFas level might be a predicting factor for prognosis.

Soluble Fas: a novel marker of inflammation in uremia

BACKGROUND

Inflammation has been associated with atherosclerotic cardiovascular disease (CVD) and anemia in patients with end-stage renal disease (ESRD). Recent studies have shown that serum levels of soluble Fas (sFas), an antiapoptotic and proinflammatory molecule, are elevated in patients with cardiac disease and patients with ESRD. We therefore sought to investigate serum levels of sFas in uremic patients and its correlation with known markers of inflammation, anemia and CVD.

METHODS

The study included 25 ESRD patients (14 on hemodialysis, 11 on CAPD), 27 patients with chronic kidney disease (CKD; creatinine clearance <50 ml/min/1.73 m2), and 14 normal control subjects. We measured serum levels of sFas, C-reactive protein (CRP), and albumin. We also investigated the association of serum sFas levels with the presence of CVD and with erythropoietin (EPO) dosage.

RESULTS

Levels of sFas were elevated in CKD and ESRD patients compared to controls. sFas levels correlated negatively with creatinine clearance. In the dialysis patients, we observed that sFas levels were higher among those with CVD. Serum levels of sFas correlated with serum levels of CRP (r=0.31; P=0.03), serum levels of albumin (r=-0.35, P=0.02), and EPO dosage (r=0.51; P=0.009).

CONCLUSION

These results suggest that sFas may be a marker of inflammation in CKD and ESRD patients.

Soluble Fas: a novel predictor of atherosclerosis in dialysis patients

BACKGROUND

Cardiovascular disease (CVD) is the leading cause of death in patients with end-stage renal disease (ESRD). Disregulation of apoptosis within the vessel wall and upregulation of the Fas/Fas-ligand (Fas-L) system contribute to the development of atherosclerosis. Cross-sectional studies have suggested that elevated plasma levels of the soluble form of Fas (sFas) are associated with CVD. However, the role of sFas and sFas-L in predicting future cardiovascular events has yet to be defined.

METHODS

We evaluated the role of plasma sFas and sFas-L levels as predictors of CVD in a prospective cohort of 107 chronic hemodialysis patients.

RESULTS

During the study period (27 months), 53 patients (49.5%) presented with at least one cardiovascular end point. On univariate analysis, baseline sFas levels were significantly associated with the occurrence of cardiovascular end points, whereas sFas-L levels were not. Using Cox proportional hazards, increased sFas levels were associated with a significantly greater risk for cardiovascular end points (P = 0.03). This effect was independent of baseline CVD history, classic risk factors for atherosclerosis (diabetes, hypercholesterolemia, hypertension, and smoking), and markers of inflammation (C-reactive protein [CRP], soluble intercellular adhesion molecule-1). Increased CRP levels also were associated with cardiovascular end points (P = 0.04). In addition, increased cardiovascular mortality was found in patients in the highest sFas tertile compared with those in the lowest tertile (27.8% versus 8.6%; P = 0.04).

CONCLUSION

Increased plasma sFas levels are predictive of future CVD. These results suggest that sFas is a novel and independent predictor of active atherosclerotic disease in patients with ESRD.

Soluble Fas is a marker of peripheral arterial occlusive disease in haemodialysis patients

BACKGROUND

Peripheral arterial occlusive disease (PAOD) including lower-extremity and cerebrovascular atherosclerosis is a leading cause of morbidity in haemodialysis patients. Recent evidence suggests that the expression of Fas, a molecule implicated in the initiation of apoptosis in various cell types, is increased at sites of atherosclerotic plaques. However, the significance of plasma levels of the soluble form of Fas (sFas) as a marker of peripheral arterial disease has yet to be defined.

METHODS

The present report is based on a cross-sectional analysis of baseline data from an ongoing prospective study designed to evaluate the role of sFas as marker of PAOD in end-stage renal disease (ESRD). We evaluated the association between sFas levels and evidence of PAOD in a cohort of 107 chronic haemodialysis patients.

RESULTS

Compared with subjects without evidence of disease (n=56), subjects with PAOD (n=51) had significantly higher plasma levels of sFas (30.0+/-8.9 vs 26.4+/-9.5 ng/ml; P=0.04). Using multiple regression, sFas was found to be associated with PAOD independently of classical risk factors for atherosclerosis (hypercholesterolaemia, diabetes, hypertension, and smoking), markers of inflammation (e.g. C-reactive protein, intercellular cell adhesion molecule type 1), and other risk factors (e.g. age, gender). An increase of one quintile in the plasma concentration of sFas was associated with an odds ratio of PAOD of 1.69 (95% CI: 1.09--2.63, P=0.01). In addition, models that incorporated sFas were significantly better at predicting PAOD than models limited to classical risk factors for atherosclerosis, alone or in combination with CRP levels (P=0.01).

CONCLUSIONS

Increased plasma levels of sFas are associated with established PAOD. These results suggest that sFas may represent a novel and independent marker of atherosclerosis.

Reactive oxygen species modulate Zn(2+)-induced apoptosis in cancer cells

Some recent evidence has suggested a protective role of zinc against cancer. The mechanism by which zinc exerts this action has not been defined and, in particular, it has not been clarified whether zinc may directly act on cancer cells and the molecular mechanisms involved in this effect. In this study, we examined the in vitro effect of zinc on the apoptosis of mouse TS/A mammary adenocarcinoma cells, studying the zinc-dependent modulation of the intracellular levels of reactive oxygen species (ROS) and of p53 and Fas/Fas ligand pathways. We showed that zinc concentrations ranging from 33.7 to 75 muM Zn(2+) induced apoptosis in mammary cancer cells. The apoptosis was associated with an increased production of intracellular ROS, and of p53 and Fas/Fas ligand mRNA and protein. Zn(2+) induced a faint metallothionein response in TS/A cells in comparison with mouse lymphocytes. The treatment of tumor cells with the antioxidant N-acetylcysteine was able to prevent Zn(2+)-induced apoptosis, as well as the increase of p53 and Fas ligand protein induced by zinc. The data demonstrate that zinc exerts a direct action on mammary cancer cells inducing ROS-mediated apoptosis and that the effect may be mediated by the ROS-dependent induction of p53 and Fas/Fas ligand.

Soluble Fas is a marker of coronary artery disease in patients with end-stage renal disease

Coronary artery disease (CAD) is the leading cause of death in patients with end-stage renal disease (ESRD). Recent evidence suggests that the expression of Fas, a molecule implicated in the initiation of apoptosis in various cell types, is increased at sites of atherosclerotic plaques. However, the significance of plasma levels of the soluble form of Fas (sFas) and its ligand (sFas-L) as markers of atherosclerosis has yet to be defined. The present report is a cross-sectional analysis of baseline data from an ongoing prospective study designed to evaluate the role of sFas and sFas-L as markers of CAD in ESRD. We evaluated the association between plasma levels of sFas and sFas-L and evidence of CAD in a cohort of 107 chronic hemodialysis patients. Plasma levels of sFas were significantly greater (P = 0.04) among subjects with (n = 64) than without evidence of CAD (n = 43). Plasma levels of sFas-L were similar in both groups. Using multivariate analysis, sFas level was found to be independently associated with CAD (P = 0.01) after adjustment for classic risk factors for CAD (hyperlipidemia, diabetes, hypertension, and smoking), markers of inflammation (C-reactive protein [CRP], intercellular adhesion molecule 1), and other confounders. An increase of one quintile in plasma concentration of sFas was associated with an odds ratio for CAD of 1.64 (95% confidence interval, 1.11 to 2.41). Models that incorporated sFas were significantly better at identifying patients with CAD than models limited to classic risk factors for atherosclerosis, alone (P = 0.008) or in combination with CRP levels (P = 0.006). In summary, increased plasma levels of sFas are associated with CAD in stable patients with ESRD. These results suggest that sFas may represent a novel and independent marker of CAD.

Increased Fas antigen in uremia accelerates adhesion of mononuclear cells to endothelial and sinovial cells via stimulated hyaluronan production

We examined influences of increased soluble Fas (sFas) and hyaluronan in uremia on apoptosis and peripheral blood mononuclear cell (MNC) adhesiveness. Synovocytes, human umbilical cord endothelial cells (HUVEC), human coronary artery smooth muscle cells (CASMC), and MNC were prepared in this study. In cultures of synovocytes, HUVEC, and CASMC, sFas or high molecular hyaluronan was added to media at medium change. After 1 day, Fas-positive cells were calculated by fluorescence-activated cell sorting. Uremic level of sFas enhanced Fas-positive cells in all cell lines (P < 0.01) not in CASMC. On the contrary, hyaluronan inhibited Fas expression in all cell lines (P < 0.05). In culture with uremic serum, Fas were induced in all cell lines. At this time, the hyaluronan levels of the supernatant were measured and hyaluronan production was estimated. In contrast to the results using sFas supplement, hyaluronan production was increased in culture with sFas and uremic sera. MNC adhesiveness was increased in synovocytes and HUVEC lines by adding hyaluronan or sFas. Higher adherent cell numbers were recognized when both sFas and hyaluronan were added to the media. A most remarkable increase in cell numbers was observed in uremic MNC suspension as compared with that of MNC from healthy subjects. In conclusion, these results indicate that increased sFas in uremia stimulates apoptosis and hyaluronan production. Both sFas and hyaluronan are responsible for accelerated MNC adhesiveness in uremia.