Mortality and Associated Risk Factors in Dialysis Patients with Cardiovascular Disease.

BACKGROUND/AIMS: Although dialysis patients have a higher risk of morbidity and mortality related to cardiovascular disease (CVD) than the general population, the mortality and associated risk factors in Asian dialysis patients with CVD have not been well examined. METHODS: In this prospective cohort study, mortality and risk factors were investigated in 591 dialysis patients who were recruited from two dialysis centers from May 1, 2009 to May 1, 2014. The Cox proportional hazards regression assessed adjusted differences in mortality risk. A multivariate analysis was also performed, comparing the CVD and non-CVD groups. RESULTS: A total of 591 patients were enrolled in this study (mean age, 52.05 ± 16.46 years [SD]; 61.8% men; 20.8% with CVD), with a median follow-up of 21.9 (maximum, 72) months. The cumulative hazard of mortality was significantly higher in CVD patients (hazard ratio [HR], 1.835; 95% confidence interval [CI], 1.023-3.293; P=0.042) than in their non-CVD counterparts after adjusting for various confounders. On multivariate Cox analysis, stroke (HR, 4.574; 95% CI, 2.149-9.736; P<0.001) was an independent predictor of all-cause mortality in the CVD group. In the non-CVD group, diabetes mellitus (HR, 2.974; 95% CI, 1.560-5.668; P=0.001) and elevated high-sensitivity C-reactive lipoprotein (hs-CRP) (HR, 1.017; 95% CI, 1.005-1.030; P=0.005) were independent predictors of all-cause mortality. CONCLUSION: All-cause mortality was significantly higher in the CVD group than in the non-CVD group. Stroke is an independent risk factor for all-cause mortality in dialysis patients with CVD. These findings warrant further studies into preventive and interventional strategies.

Prevalence and Impact on Stroke in Patients Receiving Maintenance Hemodialysis versus Peritoneal Dialysis: A Prospective Observational Study.

BACKGROUND: Patients undergoing maintenance dialysis are at increased risk of stroke, however, less is known about the prevalence and impact on stroke in the patients. METHODS: In this prospective cohort study, 590 patients undergoing hemodialysis (HD; n = 285) or peritoneal dialysis (PD; n = 305) from January 1, 2008 to December 31, 2012 were recruited. Baseline demographic, clinical, and laboratory data were collected. Timeline incidence data were analyzed using a Poisson model. The Cox proportional hazards regression assessed adjusted differences in stroke risk, a multivariate analysis was also performed. RESULTS: 62 strokes occurred during 1258 total patient-years of follow-up. Stroke occurred at a rate of 49.2/1,000 patient-years with a predominance in HD patients compared with PD patients (74.0 vs. 31.8/1,000 patient-years). The cumulative hazard of developing stroke was significantly higher in HD patients (hazard ratio [HR], 1.75; 95% confidence interval [CI], 1.15-3.62; p = 0.046) after adjusting for potential confounders. HD patients had an increased risk of ischemic stroke (HR, 2.62; 95% CI, 1.56-4.58; p = 0.002). The risk of hemorrhagic stroke was not significantly different between PD and HD patients. On multivariate Cox analysis, risk factors of stroke in both HD and PD patients were older age, diabetes, and cardiovascular disease. Other independent risk factors of stroke were lower albumin-corrected calcium in HD patients and higher triglycerides in PD patients. CONCLUSIONS: Patients undergoing PD were less likely to develop ischemic stroke than those undergoing HD. Comprehensive control of diabetes, cardiovascular disease, calcium-phosphorus metabolism, and triglyceride levels may be useful preventive strategies for stroke in dialysis patients.

Neutrophil Gelatinase-associated Lipocalin in the Prediction of Contrast-induced Nephropathy: A Systemic Review and Meta-analysis.

OBJECTIVE: The aim of this study was to investigate the predictive value of neutrophil gelatinase-associated lipocalin (NGAL) in the early diagnosis of contrast-induced nephropathy (CIN). METHODS: We searched MEDLINE and Embase until December 2014 for articles evaluating the diagnostic accuracy of plasma/serum and urinary NGAL levels to predict CIN. The primary analysis was based on a hierarchical, bivariate, generalized, linear, mixed model. Diagnostic odds ratio (DOR) and sample size-weighted area under the curve for the receiver operating characteristic (AUROC) were calculated. RESULTS: Ten studies involving 1310 patients were analyzed. Overall, the DOR/AUROC for NGAL level to predict CIN was 20.56 [95% confidence interval (CI), 9.67-43.74]/0.87 (95% CI, 0.84-0.90), with sensitivity and specificity of 0.80 (95% CI, 0.74-0.85) and 0.83 (95% CI, 0.73-0.90), respectively. Subgroup analysis showed that the diagnostic performance of the DOR/AUROC of urinary NGAL [29.48 (95% CI, 12.19-71.27)/0.87 (95% CI, 0.84-0.90)] was better than that of plasma/serum NGAL [14.63 (95% CI, 4.51-47.38)/0.85 (95% CI, 0.82-0.88)] (DOR, P = 0.005, and AUROC, P = 0.04, respectively). CONCLUSIONS: Plasma/serum and urinary NGAL levels seem to be useful biomarkers in the early prediction of CIN. Moreover, urinary NGAL levels perform better than plasma/serum NGAL.

miR-141 regulates TGF-ß1-induced epithelial-mesenchymal transition through repression of HIPK2 expression in renal tubular epithelial cells.

Epithelial-mesenchymal transition (EMT) plays a critical role in embryonic development, wound healing, tissue regeneration, cancer progression and organ fibrosis. The proximal tubular epithelial cells undergo EMT, resulting in matrix-producing fibroblasts and thereby contribute to the pathogenesis of renal fibrosis. The profibrotic cytokine, TGF­ß, is now recognized as the main pathogenic driver that has been shown to induce EMT in tubular epithelial cells. Increasing evidence indicate that HIPK2 dysfunction may play a role in fibroblasts behavior, and therefore, HIPK2 may be considered as a novel potential target for anti-fibrosis therapy. Recently, members of the miR-200 family (miR­200a, b and c and miR­141) have been shown to inhibit EMT. However, the steps of the multifactorial renal fibrosis progression that these miRNAs regulate, particularly miR­141, are unclear. To study the functional importance of miR­141 in EMT, a well­established in vitro EMT assay was used to demonstrate renal tubulointerstitial fibrosis; transforming growth factor­ß1­induced EMT in HK-2 cells. Overexpression of miR­141 in HK­2 cells, either with or without TGF­ß1 treatment, hindered EMT by enhancing E­cadherin and decreasing vimentin and fibroblast­specific protein 1 expression. miR­141 expression was repressed during EMT in a dose­ and time­dependent manner through upregulation of HIPK2 expression. Ectopic expression of HIPK2 promoted EMT by decreasing E-cadherin. Furthermore, co-transfection of miR­141 with the HIPK2 ORF clone partially inhibited EMT by restoring E­cadherin expression. miR­141 downregulated the expression of HIPK2 via direct interaction with the 3'-untranslated region of HIPK2. Taken together, these findings aid in the understanding of the role and mechanism of miR­141 in regulating renal fibrosis via the TGF­ß1/miR-141/HIPK2/EMT axis, and miR-141 may represent novel biomarkers and therapeutic targets in the treatment of renal fibrosis.

Correlation of Doppler parameters with renal pathology: A study of 992 patients.

Ultrasound examination is a non-invasive diagnostic technique that is used on patients with suspected or established renal disease. The purpose of this study was to determine the role of intrarenal Doppler ultrasonography in the assessment of the renal pathology of patients with chronic kidney disease (CKD), as shown by kidney biopsy. This retrospective analysis enrolled 992 consecutive patients with CKD who underwent intrarenal Doppler ultrasonography and a kidney biopsy at the Departments of Nephrology of three hospitals between January 2006 and December 2010. Doppler parameters, including the peak systolic velocity (PSV), end-diastolic velocity and resistive index (RI) of the interlobar arteries, were compared with the renal biopsy findings. The RI of the interlobar arteries was correlated with the estimated glomerular filtration rate and the histological damage scores, demonstrating the most evident correlation with the tubulointerstitial damage (TI) score among the three histological components. The PSV of the interlobar arteries increased as the CKD stage progressed and correlated with a number of the renal histological changes, including the glomerulosclerosis and TI scores. The RI and PSV of the interlobar artery are correlated with the histopathological pattern in CKD. Thus, the RI and PSV of the interlobar artery may be potential indicators for monitoring the progression of renal damage.

[Preparation of the trimeric subunits of recombinant human mannan-binding lectin and analysis of its bioactivity].

OBJECTIVE: To prepare the trimeric subunits of recombinant human mannan-binding lectin (MBL) with biological activities. METHODS: A prokaryotic expression vector containing human MBL N-terminal deletant (rhMBLδN) gene we previously constructed was transformed into E. coli for efficient expression of rhMBLδN fusion protein. Based on the principle that the collagen polypeptides tend to self-assembly into the tertiary structure of proteins by forming a triple helix due to the characteristic properties of the collagen proteins, rhMBLδN fusion protein was limitedly hydrolyzed with thrombin. The obtained rhMBLδN polypeptide was repeatedly dialyzed in 50 mmol/L PBS (pH7.2) and ddH(2)O, and the final product was analyzed for its bioactivities using a ligand-binding assay and a C4d deposition assay. RESULTS: rhMBLδN polypeptide with a relative molecular mass of about 20 000 was obtained by limited proteolysis of rhMBLδN fusion protein with thrombin. Repeated dialyses of rhMBLδN polypeptides in 50 mmol/L PBS and ddH(2)O resulted in the isolation of the trimeric subunit trhMBLδN (with a relative molecular mass of about 50 000), which contained a collagen-like helix. The trhMBLδN protein had a higher ligand-binding activity than rhMBLδN polypeptide, and acquired the activity to initiate the lectin pathway of complement activation, but the activities were lower than those of natural MBL. CONCLUSION: We have successfully obtained the bioactive trimeric subunit of rhMBL, trhMBLδN, and this structural subunit is also the functional subunit of the MBL molecule.

[Effects of urokinase on renal interstitial fibrosis and transforming growth factor-beta1 in the kidney of rats with chronic cyclosporine A nephropathy].

OBJECTIVE: To investigate the effects of urokinase on renal interstitial fibrosis and transforming growth factor-beta1 (TGF-beta1) in the kidney of rats with chronic cyclosporine A nephropathy. METHODS: Male Sprague-Dawley rats on low-salt diet were randomly divided into control (VH), CsA-treated (CsA), CsA+2000 U/kg.day uPA (CsA+U2) and CsA+6000 U.kg.3 days (CsA+U6) groups. The rats were given CsA intragastrically for 4 weeks to prepare CsA-induced chronic nephropathy model. Masson staining was used to examine fibrin deposition. Western blotting and reversal transcription polymerase chain reaction were employed to evaluate urokinase-type plasminogen activator (uPA) and TGF-beta1 protein and gene expressions, respectively. RESULTS: CsA can increase fibrin deposition and the expression of TGF-beta1 in the renal tissue, which were significantly reduced after uPA treatment (P<0.05). CONCLUSION: Continuous low-dose uPA treatment can reduce renal interstitial fibrosis in rats possibly in association with its inhibitory effect on TGF-beta1 expression.

[Role of integrin-linked kinase in renal tubular epithelial-mesenchymal transition and the regulatory effect of urokinase on its expression in mice with obstructive nephropathy].

OBJECTIVE: To investigate the role of integrin-linked kinase (ILK) on renal tubular epithelial-mesenchymal transition and the regulatory effect of urokinase on LIK expression in mice with obstructive nephropathy. METHODS: Normal male mice were randomly divided into sham-operated group (n=20), unilateral ureteral obstruction (UUO) group (n=28), and UUO with urokinase treatment group (uPA, n=28), and UUO was induced surgically in the latter two groups. The mice were sacrificed on days l, 3, 7 and 14 after the surgery, and renal interstitial fibrosis (RIF) was graded according to the result of Masson staining. The expression of ILK in the renal tissues of the rats was examined by immunofluorescence staining and Western blotting, and the expression of E-cadherin was detected by immunohistochemistry. RT-PCR was used to examine the mRNA expressions of ILK, E-cadherin and alpha-smooth muscle actin (alpha-SMA). RESULTS: The expressions of ILK mRNA and protein were significantly increased in UUO group, but significantly decreased by treatment with uPA (P<0.05). The expression of alpha-SMA mRNA level was significantly increased, while E-cadherin decreased in mice with UUO on day 3 after the surgery. Treatment with uPA significantly inhibited such effects (P<0.05). CONCLUSION: ILK plays an important role in renal interstitial fibrosis by mediating epithelial-mesenchymal transition. Urokinase attenuates renal tubulointerstitial fibrosis in mice with UUO possibly by inhibiting ILK expression and preventing tubular epithelial-mesenchymal transition.

[Effect of urokinase on renal interstitial inflammation in rats with chronic cyclosporine A nephropathy and its possible mechanism].

OBJECTIVE: To investigate the protective effect of urokinase on renal interstitial inflammation and fibrosis in rats with chronic cyclosporine A (CsA)-induced nephropathy. METHODS: Male SD rats were fed on low salt diet (0.05% sodium) for 7 days and randomized into 4 groups for treatment with CsA, CsA+continuous low-dose uPA (U2), intermittent CsA+ high-dose uPA (U6) or vehicle (control group). In the former 3 groups, the rats were subjected to daily intragastric administration of CsA (25 mg/kg) for 4 weeks to establish CsA-induced chronic nephropathy model, and those in U2 and U6 groups were given uPA at 2000 U/kg daily or at 6000 U/kg every 3 days, respectively. Four weeks after the treatment, the renal function and 24-h proteinuria were assessed, and Masson staining was used for examining fibrin deposition. Semi-quantitative immunohistochemical staining was employed for evaluation of ED-1-positive cells, urokinase-type plasminogen activator (uPA) and transforming growth factor-beta1 (TGF-beta 1). RESULTS: Four weeks after the treatment, the CsA-treated rats showed significantly elevated serum creatinine (Scr), blood urea nitrogen (BUN) and increased urine proteins. Continuous administration of low-dose uPA resulted in significantly reduced Scr, BUN and 24-h urine protein excretion, while intermittent high-dose uPA treatment did not produce such changes. CsA increased fibrin deposition, total number of macrophages in renal interstitium and TGF-beta1 expression in the renal tissue, which were significantly reduced in U2 group (P<0.05) but not in U6 group (P>0.05). CONCLUSION: Continuous administration of low-dose uPA may reduce interstitial fibrin deposition and alleviate renal interstitial inflammation in rats with chronic CsA nephropathy, possibly by reducing the number of macrophages and TGF-beta1 expression in the renal tissue.