A novel electrochemical strategy to detect hydrogen peroxide by utilizing peroxidase-mimicking activity of cerium oxide/graphene oxide nanocomposites.

We herein describe a novel electrochemical strategy to detect hydrogen peroxide (H2O2) by utilizing the peroxidase-mimicking activity of cerium oxide nanoparticles (CeO2 NP) and reduced graphene oxide (rGO). Particularly, CeO2 NP/rGO nanocomposites were deposited on the commercial electrode by a very convenient and direct electrochemical reduction of graphene oxide. Due to the peroxidase-mimicking activity of CeO2 NP and the outstanding electrochemical properties of reduced graphene oxide, the reduction current of H2O2 was greatly enhanced. Based on this strategy, we reliably determined H2O2 down to 1.67 µM with excellent specificity and further validated its practical capabilities by robustly detecting H2O2 present in heterogeneous human serum samples. We believe that this work could serve as a new facile platform for H2O2 detection.

Associations among Alzheimer disease, depressive disorder, and risk of end-stage kidney disease in elderly people.

BACKGROUND: Alzheimer disease (AD) and depressive disorder (DD) are prevalent among elderly end-stage kidney disease (ESKD) patients. However, whether preexisting mental health disorders increase the risk of ESKD is not well understood. The risk of incident ESKD in patients with or without underlying AD or DD was evaluated in a nationwide cohort of elderly people in Republic of Korea. METHODS: This study used data from the National Health Insurance Service-Senior cohort in Republic of Korea. Among the 558,147 total subjects, 49,634 and 54,231 were diagnosed with AD (AD group) or DD (DD group), respectively, during the follow-up period. Propensity score matching was conducted to create non-AD and non-DD groups of subjects. AD and DD diagnoses were analyzed as time-varying exposures, and the study outcome was development of ESKD. RESULTS: The incidence rates of ESKD were 0.36 and 1.17 per 1,000 person-years in the non-AD and AD groups, respectively. After adjustment for clinical variables and competing risks of death, the risk of incident ESKD was higher in the AD group than in the nonAD group (hazard ratio [HR], 1.67; 95% confidence interval [CI], 1.34-2.08). The incidence rates of ESKD in the non-DD and DD groups were 0.36 and 0.91 per 1,000 person-years, respectively. The risk of ESKD development was also higher in the DD group than the non-DD group (HR, 1.44; 95% CI, 1.19-1.76). CONCLUSION: The risk of ESKD development was higher in subjects diagnosed with AD or DD, suggesting that central nervous system diseases can adversely affect kidney function in elderly people.

Association of statin treatment with hepatocellular carcinoma risk in end-stage kidney disease patients with chronic viral hepatitis.

Statin use in end-stage kidney disease (ESKD) patients are not encouraged due to low cardioprotective effects. Although the risk of hepatocellular carcinoma (HCC), a frequently occurring cancer in East Asia, is elevated in ESKD patients, the relationship between statins and HCC is not known despite its possible chemopreventive effect. The relationship between statin use and HCC development in ESKD patients with chronic hepatitis was evaluated. In total, 6165 dialysis patients with chronic hepatitis B or C were selected from a national health insurance database. Patients prescribed with ≥ 28 cumulative defined daily doses of statins during the first 3 months after dialysis commencement were defined as statin users, while those not prescribed with statins were considered as non-users. Primary outcome was the first diagnosis of HCC. Sub-distribution hazard model with inverse probability of treatment weighting was used to estimate HCC risk considering death as competing risk. During a median follow-up of 2.8 years, HCC occurred in 114 (3.2%) statin non-users and 33 (1.2%) statin users. The HCC risk was 41% lower in statin users than in non-users (sub-distribution hazard ratio, 0.59; 95% confidence interval [CI], 0.42-0.81). The weighted incidence rate of HCC was lower in statin users than in statin non-users (incidence rate difference, - 3.7; 95% CI - 5.7 to - 1.7; P < 0.001). Incidence rate ratio (IRR) was also consistent with other analyses (IRR, 0.56; 95% CI, 0.41 to 0.78; P < 0.001). Statin use was associated with a lower risk of incident HCC in dialysis patients with chronic hepatitis B or C infection.

Sleep apnea is associated with residual kidney function and mortality in patients with peritoneal dialysis: Prospective cohort study.

INTRODUCTION: Fluid overload and sleep apnea (SA) are known risk factors for mortality in dialysis patients. Although incidence and severity of SA were shown higher in peritoneal dialysis (PD) patients than in hemodialysis patients, data regarding the association of SA with body fluid status and mortality are limited. Therefore, the association of SA with body fluid status and mortality were investigated in a prospective cohort with patients undergoing PD. METHODS: The present study included 103 prevalent PD patients who were followed up for median 70 months. At baseline, the subjects underwent in-home polysomnography, bioelectrical impedance analysis, and urea kinetics. Excessive daytime sleepiness and sleep quality were assessed using sleep questionnaires. SA was defined as apnea/hypopnea index higher than 15 events per hour. RESULTS: Sleep apnea was diagnosed in 57 (55.3%) patients (SA group); the subjects had significantly higher extracellular water (10.3 ± 1.4 vs. 9.2 ± 1.8, p = 0.001) and lower residual kidney function (RKF) (3.3 ± 3.3 vs. 5.9 ± 7.2, p = 0.02) compared with subjects in the non-SA group. SA was significantly associated with RKF [odds ratio, 0.84; 95% confidence interval (CI), 0.73-0.97] in multivariable logistic regression analysis. In multivariable Cox regression models, SA was a significant predictor of mortality in PD patients (adjusted hazard ratio, 5.74; 95% CI, 1.09-30.31) after adjusting for well-known risk factors. CONCLUSIONS: Sleep apnea was very common in PD patients and significantly associated with lower RKF. SA was also a novel risk predictor of mortality in PD patients.

Reduction in proteinuria after immunosuppressive therapy and long-term kidney outcomes in patients with immunoglobulin A nephropathy.

BACKGROUND/AIMS: Despite controversy regarding the benefits of immunosuppressive therapy in immunoglobulin A nephropathy (IgAN), clinical outcomes may vary depending on the patient's responsiveness to this therapy. This study evaluated long-term kidney outcomes according to the extent of proteinuria reduction after immunosuppression in IgAN patients. METHODS: Among 927 patients with biopsy-proven IgAN, 127 patients underwent immunosuppression. Time-averaged urine protein-creatinine ratio before and within 1 year after start of immunosuppression were calculated, and responsiveness to immunosuppression was assessed as the reduction of proteinuria between the two periods. Patients were classified into tertiles according to the extent of proteinuria reduction. We compared the slopes of estimated glomerular filtration rate (eGFR) decline using a linear mixed model, and estimated hazard ratios (HRs) for disease progression (defined as development of a ≥ 30% decline in eGFR or end-stage renal disease) using a Cox proportional hazard model. RESULTS: Median extent of proteinuria reduction was -2.1, -0.9, and -0.2 g/gCr in the first, second, and third tertiles, respectively. There were concomitant changes in the slopes of annual eGFR decline: -2.03, -2.44, and -4.62 mL/min/1.73 m2 among the first, second, and third tertiles, respectively. In multivariable Cox analysis, the HRs (95% confidence intervals) for disease progression were 0.30 (0.12 to 0.74) in the first tertile and 0.70 (0.34 to 1.45) in the second tertile compared with the thirdtertile. CONCLUSION: This study showed that greater proteinuria reduction after immunosuppression was associated with a lower risk of disease progression in patients with IgAN, suggesting that responsiveness to immunosuppression may be an important determinant of kidney outcomes.

Systolic blood pressure and chronic kidney disease progression in patients with primary glomerular disease.

INTRODUCTION: Many current guidelines on optimal target blood pressure (BP) for chronic kidney disease (CKD) patients are largely based on studies in diabetic and hypertensive patients. However, there have been few studies in patients with glomerular diseases. METHODS: We retrospectively studied the longitudinal association between BP and CKD progression in 1,066 biopsy-proven patients diagnosed with primary glomerular diseases, including IgA nephropathy, membranous nephropathy (MN), and focal segmental glomerulosclerosis (FSGS), between 2005 and 2017. The main predictor was time-updated systolic blood pressure (SBP) at every clinic visit. The primary outcome was a composite one including ≥ 50% decrease in estimated glomerular filtration rate (eGFR) from the baseline, and end-stage kidney disease (ESKD). RESULTS: During 5009 person-years of follow-up, the primary outcome occurred in 157 (14.7%) patients. In time-varying Cox model, the adjusted hazard ratios (HRs) (95% confidence interval (CI)) for the primary outcome were 1.48 (0.96-2.29), 2.07 (1.22-3.52), and 2.53 (1.13-5.65) for SBP of 120-129, 130-139, and ≥ 140 mmHg, respectively, compared with SBP < 120 mmHg. This association was particularly evident in patients with elevated proteinuria. However, there was no association between baseline SBP and adverse kidney outcomes. Finally, prediction models failed to show the improvement of predictive performance of SBP compared with that of remission status. Moreover, patients with remission and less controlled SBP had better kidney outcomes than those with non-remission and well-controlled SBP. CONCLUSION: Among patients with glomerular disease, higher time-updated SBP was significantly associated with higher risk of CKD progression. However, the clinical significance of blood pressure was less powerful than remission status.

Association of Reproductive Lifespan Duration and Chronic Kidney Disease in Postmenopausal Women.

OBJECTIVE: To investigate the relationship between endogenous estrogen exposure and renal function, the association of female reproductive life span duration (RLD) and chronic kidney disease (CKD) was analyzed in postmenopausal women. PATIENTS AND METHODS: Data were retrieved from the Korean Genome and Epidemiology Study, which was constructed from May 1, 2001, through December 25, 2017. A total of 50,338 and 3155 postmenopausal women were each included in the cross-sectional and longitudinal analyses. The RLD was determined by subtracting the age at menarche from the age at menopause. Participants were grouped into RLD quartiles. Participants with estimated glomerular filtration rates less than 60 mL/min/1.73 m2 were regarded to have CKD. RESULTS: In the cross-sectional analysis, mean ± SD age and estimated glomerular filtration rate were 56.3±4.9 years and 93.1±13.6 mL/min/1.73 m2, respectively. Mean ± SD RLD was 34.2±4.0 years. A total of 765 of 50,338 (1.52%) women were found to have CKD. Logistic regression analysis revealed that the odds ratio for CKD was lower in groups with longer RLDs as compared with the shortest RLD group. In longitudinal analysis, postmenopausal women with normal kidney function were followed up for 9.7 years and incident CKD occurred in 221 of 3155 (7.00%) participants. Cox analysis revealed that the risk for CKD development was significantly lower in longer RLD groups. This finding was significant even after adjustments for confounding factors. CONCLUSION: The risk for CKD was lower in women with longer RLDs. The amount of endogenous estrogen exposure could be a determining factor for renal function in postmenopausal women.