Seasonality in hip fracture among haemodialysis patients and kidney transplant recipients in South Korea.

AIM: The seasonality of hip fracture in haemodialysis (HD) patients and kidney transplant recipients (KTRs) have not been reported. We assessed seasonal variations in hip fractures among patients with end-stage kidney disease who undergo maintenance HD and KTRs. METHODS: Using the Korean National Health Insurance System database from January 2012 to December 2017, monthly counts of hip fracture were calculated among HD patients (n = 77 420) and KTRs (n = 8921). The 6-year normalized monthly fraction and seasonal fractions of hip fractures were calculated. A cosinor analysis was performed to determine the seasonality of the monthly incidence of hip fractures. RESULTS: The 6-year average monthly fraction of hip fractures was lowest in June and highest in October in HD patients, and lowest in February and highest in November in KTRs. The 6-year average seasonal fraction among HD patients was lowest in summer and highest in winter, and lowest in summer and highest in autumn among KTRs, but there was no significant difference. The incidence ratio of hip fractures was lowest in June and highest in January in HD patients, and lowest in August and highest in November in KTRs. On cosinor analysis, HD patients showed significant seasonality in hip fracture incidence, with a trough in summer and a peak in winter (p = .031), whereas KTRs did not exhibit a significant trend (p = .44). CONCLUSION: Hip fractures occurred more frequently in winter and less frequently in summer in patients undergoing HD, whereas KTRs did not show a seasonal trend.

The Protective Effect of Zebularine, an Inhibitor of DNA Methyltransferase, on Renal Tubulointerstitial Inflammation and Fibrosis.

Renal fibrosis, the final pathway of chronic kidney disease, is caused by genetic and epigenetic mechanisms. Although DNA methylation has drawn attention as a developing mechanism of renal fibrosis, its contribution to renal fibrosis has not been clarified. To address this issue, the effect of zebularine, a DNA methyltransferase inhibitor, on renal inflammation and fibrosis in the murine unilateral ureteral obstruction (UUO) model was analyzed. Zebularine significantly attenuated renal tubulointerstitial fibrosis and inflammation. Zebularine decreased trichrome, α-smooth muscle actin, collagen IV, and transforming growth factor-ß1 staining by 56.2%. 21.3%, 30.3%, and 29.9%, respectively, at 3 days, and by 54.6%, 41.9%, 45.9%, and 61.7%, respectively, at 7 days after UUO. Zebularine downregulated mRNA expression levels of matrix metalloproteinase (MMP)-2, MMP-9, fibronectin, and Snail1 by 48.6%. 71.4%, 31.8%, and 42.4%, respectively, at 7 days after UUO. Zebularine also suppressed the activation of nuclear factor-κB (NF-κB) and the expression of pro-inflammatory cytokines, including tumor necrosis factor-α, interleukin (IL)-1ß, and IL-6, by 69.8%, 74.9%, and 69.6%, respectively, in obstructed kidneys. Furthermore, inhibiting DNA methyltransferase buttressed the nuclear expression of nuclear factor (erythroid-derived 2)-like factor 2, which upregulated downstream effectors such as catalase (1.838-fold increase at 7 days, p < 0.01), superoxide dismutase 1 (1.494-fold increase at 7 days, p < 0.05), and NAD(P)H: quinone oxidoreduate-1 (1.376-fold increase at 7 days, p < 0.05) in obstructed kidneys. Collectively, these findings suggest that inhibiting DNA methylation restores the disrupted balance between pro-inflammatory and anti-inflammatory pathways to alleviate renal inflammation and fibrosis. Therefore, these results highlight the possibility of DNA methyltransferases as therapeutic targets for treating renal inflammation and fibrosis.

The combined prognostic significance of alkaline phosphatase and vascular calcification in patients with end-stage kidney disease.

BACKGROUND AND AIMS: Little is known about the interaction between serum alkaline phosphatase (ALP) and vascular calcification (VC) affecting cardiovascular events (CVE) and mortality in end-stage kidney disease (ESKD) patients. This study investigated the combined effect of ALP and VC on prognosis in ESKD patients starting dialysis. METHODS AND RESULTS: Data from 587 ESKD patients treated at a single center between January 2006 and July 2017 were retrospectively evaluated. VC was assessed by the aortic calcification index (ACI) using abdominal computed tomography. Patients were stratified into four groups according to the median ACI (17.18) and serum ALP value (108.0 U/L) as low ACI-low ALP, low ACI-high ALP, high ACI-low ALP, or high ACI-high ALP. The association between ALP and VC and the composite of CVE and death was analyzed. During a median follow-up of 3.1 years (range, 1.5-5.6 years), 140 patients (23.8%) developed CVE and 130 deaths (22.1%) occurred. In the stratified analysis, patients with high ACI-low ALP had a greater risk of the composite endpoint than patients with low ACI-low ALP (adjusted hazard ratio, 2.09; 95% confidence interval, 1.58-2.60; P = 0.004). Patients with high ACI-high ALP had the greatest risk (adjusted hazard ratio, 2.25; 95% confidence interval, 1.77-2.72; P = 0.001). The interaction between ACI and ALP on CVE and mortality was statistically significant (P < 0.05). CONCLUSIONS: The combined effect of VC and higher ALP was associated with a greater risk of CVE and death, and high serum ALP amplified the risk associated with VC in ESKD patients starting dialysis.

Factors associated with low trabecular bone scores in patients with end-stage kidney disease.

The trabecular bone score (TBS) is a textural index that indirectly assesses bone trabecular microarchitecture using lumbar spine images obtained by dual-energy X-ray absorptiometry (DXA). This study compared the TBS of patients with end-stage kidney disease (ESKD) with that of matched controls to identify risk factors associated with a low TBS. TBS and bone mineral density (BMD) were assessed in ESKD patients (n = 76) and age- and sex-matched control subjects (n = 76) using DXA. The TBS of both groups was then compared, and risk factors associated with a low TBS (defined as ≤ 1.31) were evaluated. The mean TBS in the ESKD group was significantly lower than that in the control group (1.34 ± 0.15 vs. 1.43 ± 0.08, respectively; p < 0.001). More subjects in the ESKD group had a low TBS [34.2% (ESRD) vs. 5.3% (controls); p < 0.001]. The TBS was negatively correlated with age, alkaline phosphatase and C-reactive protein levels, and dialysis vintage, and positively correlated with BMD at the lumbar spine, femoral neck, and hip. Multivariate analysis identified lower estimated glomerular filtration rate and increased C-reactive protein levels as being significantly associated with a low TBS. In conclusion, ESKD patients had abnormal bone microarchitecture (as assessed by the TBS). The TBS was positively correlated with BMD. Renal function and inflammatory marker levels were independently associated with a low TBS. Thus, TBS may be a useful clinical tool for assessing cancellous bone connectivity in ESKD patients.

Bioimpedance spectroscopy-guided fluid management in peritoneal dialysis patients with residual kidney function: A randomized controlled trial.

AIM: Bioimpedance spectroscopy (BIS) allows volume status to be assessed objectively. This study evaluated the effect of BIS-guided fluid management on residual kidney function (RKF), volume status, and cardiovascular events in peritoneal dialysis (PD) patients. METHODS: A multicenter, prospective, randomized, controlled trial was conducted over 12 months in 2013-2017. Non-anuric PD patients (urine volume ≥ 500 mL/day) were randomized to clinical method-guided management (n = 98) or BIS-guided management (n = 103). The volume in the BIS group was controlled with BIS, with the aim of achieving the target overhydration (OH) goal of -2.0 to +2.0 L. The volume in the control group was controlled by clinical assessment alone. The groups were compared in terms of change in RKF and volume status at 12 months relative to baseline and in terms of cardiovascular event rates during a median follow-up period of 36 months. RESULTS: Compared with the controls, the BIS group did not show a significant improvement in change in OH, after adjustments were made for covariates (P = 0.191). The two groups did not differ in terms of delta OH, renal creatinine and urea clearance, and 24 h urine volume. The control and BIS groups also did not differ significantly in terms of change in peritoneal ultrafiltration volume, blood pressure, body weight and echocardiographic variables or in cardiovascular event rates (10.2% vs 11.3%; P = 0.953). CONCLUSION: Bioimpedance spectroscopy-guided fluid management did not show an additional benefit to achieve euvolemia, and did not affect the decline in RKF in non-anuric PD patients.

The Adiponectin Receptor Agonist AdipoRon Ameliorates Diabetic Nephropathy in a Model of Type 2 Diabetes.

Adiponectin exerts renoprotective effects against diabetic nephropathy (DN) by activating the AMP-activated protein kinase (AMPK)/peroxisome proliferative-activated receptor-α (PPARα) pathway through adiponectin receptors (AdipoRs). AdipoRon is an orally active synthetic adiponectin receptor agonist. We investigated the expression of AdipoRs and the associated intracellular pathways in 27 patients with type 2 diabetes and examined the effects of AdipoRon on DN development in male C57BLKS/J db/db mice, glomerular endothelial cells (GECs), and podocytes. The extent of glomerulosclerosis and tubulointerstitial fibrosis correlated with renal function deterioration in human kidneys. Expression of AdipoR1, AdipoR2, and Ca2+/calmodulin-dependent protein kinase kinase-ß (CaMKKß) and numbers of phosphorylated liver kinase B1 (LKB1)- and AMPK-positive cells significantly decreased in the glomeruli of early stage human DN. AdipoRon treatment restored diabetes-induced renal alterations in db/db mice. AdipoRon exerted renoprotective effects by directly activating intrarenal AdipoR1 and AdipoR2, which increased CaMKKß, phosphorylated Ser431LKB1, phosphorylated Thr172AMPK, and PPARα expression independently of the systemic effects of adiponectin. AdipoRon-induced improvement in diabetes-induced oxidative stress and inhibition of apoptosis in the kidneys ameliorated relevant intracellular pathways associated with lipid accumulation and endothelial dysfunction. In high-glucose-treated human GECs and murine podocytes, AdipoRon increased intracellular Ca2+ levels that activated a CaMKKß/phosphorylated Ser431LKB1/phosphorylated Thr172AMPK/PPARα pathway and downstream signaling, thus decreasing high-glucose-induced oxidative stress and apoptosis and improving endothelial dysfunction. AdipoRon further produced cardioprotective effects through the same pathway demonstrated in the kidney. Our results show that AdipoRon ameliorates GEC and podocyte injury by activating the intracellular Ca2+/LKB1-AMPK/PPARα pathway, suggesting its efficacy for treating type 2 diabetes-associated DN.

Inhibition of p300/CBP-Associated Factor Attenuates Renal Tubulointerstitial Fibrosis through Modulation of NF-kB and Nrf2.

p300/CBP-associated factor (PCAF), a histone acetyltransferase, is involved in many cellular processes such as differentiation, proliferation, apoptosis, and reaction to cell damage by modulating the activities of several genes and proteins through the acetylation of either the histones or transcription factors. Here, we examined a pathogenic role of PCAF and its potential as a novel therapeutic target in the progression of renal tubulointerstitial fibrosis induced by non-diabetic unilateral ureteral obstruction (UUO) in male C57BL/6 mice. Administration of garcinol, a PCAF inhibitor, reversed a UUO-induced increase in the renal expression of total PCAF and histone 3 lysine 9 acetylation and reduced positive areas of trichrome and α-smooth muscle actin and collagen content. Treatment with garcinol also decreased mRNA levels of transforming growth factor-ß, matrix metalloproteinase (MMP)-2, MMP-9, and fibronectin. Furthermore, garcinol suppressed nuclear factor-κB (NF-κB) and pro-inflammatory cytokines such as tumor necrosis factor-α and IL-6, whereas it preserved the nuclear expression of nuclear factor erythroid-derived 2-like factor 2 (Nrf2) and levels of Nrf2-dependent antioxidants including heme oxygense-1, catalase, superoxide dismutase 1, and NAD(P)H:quinone oxidoreductase 1. These results suggest that the inhibition of inordinately enhanced PCAF could mitigate renal fibrosis by redressing aberrant balance between inflammatory signaling and antioxidant response through the modulation of NF-κB and Nrf2.

Prognostic Utility of Soluble Suppression of Tumorigenicity 2 level as a Predictor of Clinical Outcomes in Incident Hemodialysis Patients.

Background: The suppression of tumorigenicity 2 (ST2) is associated with cardiac remodeling and tissue fibrosis. It is well known as a novel biomarker on predictor of cardiovascular events in patients with heart failure. In patients needed to start dialysis treatment, most of them had congestive heart failure. However, the prognostic implications of serum ST2 level are unknown in incident hemodialysis patients. Methods: A total 182 patients undergoing incident hemodialysis were consecutively enrolled from November 2011 to December 2014. These patients were classified into two groups according to their median ST2 levels. The two groups were subsequently compared with respect to their major adverse cerebro-cardiovascular events (MACCE) including all-cause mortality, heart failure admission, acute coronary syndrome, and nonfatal stroke. Results: The median duration of follow up was 628 days (interquartile range 382 to 1,052 days). ST2 was significant correlated with variable echocardiographic parameters. The parameters of diastolic function, deceleration time of the early filing velocity and maximal tricuspid regurgitation velocity were independently associated with the ST2 levels. High ST2 group had significantly higher incidence of all-cause mortality, and MACCE. High ST2 was a significant independent predictor of MACCE (adjusted hazard ratio 2.33, 95% confidence interval 1.12 to 4.87, p=0.024). Conclusion: The ST2 is associated with diastolic function and may be a predictor of clinical outcomes in incident hemodialysis patients.

Vascular calcification and left ventricular hypertrophy in hemodialysis patients: interrelationship and clinical impacts.

Background: We examined the relationship and combined effect of vascular calcification (VC) and left ventricular hypertrophy (LVH) on deaths and cardiovascular events (CVEs) in hemodialysis (HD) patients. Methods: Maintenance HD patients (n=341) were included. Echocardiography data and plain chest radiographs were used to assess LVH and aortic arch VC. Results: VC was found in 100 patients (29.3%). LVH was more prevalent in patients with VC compared with those without VC (70% vs. 50.2%, P=0.001). VC was independently associated with a 2.42-fold increased risk of LVH (95% CI, 1.26-4.65). In multivariate analysis, compared with patients with neither VC nor LVH, the coexistence of VC and LVH was independently associated with CVE (HR, 2.01; 95% CI, 1.09-3.72), whereas VC or LVH alone was not. Patients with both VC and LVH had the highest risk for a composite event of deaths or CVE (HR, 1.88; 95% CI, 1.15-3.06). Significant synergistic interaction was observed between VC and LVH (P for interaction=0.039). Conclusions: VC was independently associated with LVH. The coexistence of VC and LVH was associated with higher risk of deaths and CVEs than either factor alone. VC and LVH showed a synergistic interaction for the risk of deaths and CVEs.

The Clinical Usefulness of Measurement of Visceral Fat Area Using Multi-Frequency Bioimpedance: The Association with Cardiac and Renal Function In General Population with Relatively Normal Renal Function.

Background: This study was performed to determine the clinical usefulness of measurement of visceral fat area (VFA) using bioimpedance analysis in relation with left ventricular hypertrophy (LVH), diastolic dysfunction parameters, and decreased estimated glomerular filtration rate (eGFR). Methods: A cross-sectional analysis was performed on 1028 patients with eGFR≥60 ml/min/1.73m2, aged 40 - 64 years, and who underwent routine health check-ups. Subjects were divided into tertiles based on their VFA. Associations of VFA with echocardiographic parameters and eGFR were evaluated. Results: Across the VFA teriltes, there was a significant trend for increasing left ventricular mass index (LVMi), left atrial diameter (LAD), and ratio of early mitral inflow velocity to peak mitral annulus velocity (E/E' ratio) and that for decreasing ratio of early to late mitral inflow peak velocities (E/A ratio) and eGFR. In multivariate linear regression analysis, log-transformed VFA was significantly associated with increased LVMi, LAD, and E/E' ratio, and with decreased E/A ratio and eGFR. After adjustment for body mass index, log-transformed VFA remained as a significant determinant for E/A ratio. Conclusion: VFA may be associated with LV structure and diastolic function, and decreased eGFR in middle-aged adults with normal or mildly impaired renal function.

Gender-Specific Associations between Low Skeletal Muscle Mass and Albuminuria in the Middle-Aged and Elderly Population.

Objective This study assessed gender-specific associations between low muscle mass (LMM) and albuminuria. Methods Data from the Korea National Health and Nutrition Examination Survey 2011 were employed. The study consisted of 1,087 subjects (≥50 years old). Skeletal muscle index (SMI) was defined as the weight-adjusted appendicular skeletal muscle mass. Mild LMM and severe LMM were defined as SMI that were 1-2 and >2 standard deviations below the sex-specific mean appendicular skeletal muscle mass of young adults, respectively. Increased albuminuria was defined as albumin-to-creatinine ratio ≥30mg/g Results Men with mild and severe LMM were significantly more likely to have increased albuminuria (15.2% and 45.45%, respectively) than men with normal SMI (9.86%, P<0.0001), but not women. Severe LMM associated independently with increased albuminuria in men (OR=7.661, 95% CI=2.72-21.579) but not women. Severe LMM was an independent predictor of increased albuminuria in hypertensive males (OR=11.449, 95% CI=3.037-43.156), non-diabetic males (OR=8.782, 95% CI=3.046-25.322), and males without metabolic syndrome (MetS) (OR=8.183, 95% CI=1.539-43.156). This was not observed in males without hypertension, males with diabetes or MetS, and all female subgroups. Conclusion Severe LMM associated with increased albuminuria in men, especially those with hypertension and without diabetes or MetS.

Identification of a novel GLA mutation (Y88C) in a Korean family with Fabry nephropathy: a case report.

BACKGROUND: Fabry disease is a rare X-linked lysosomal storage disorder caused by α-galactosidase A deficiency. With the advancement of molecular diagnostic tools, more disease-causing mutations in α-galactosidase A (GLA) have been identified in Fabry disease. We found a novel mutation in a Korean family with predominant renal manifestations of the disease. CASE PRESENTATION: A 24-year-old man who wanted to donate a kidney to his 28-year-old brother with end-stage renal disease of unknown cause was evaluated. The 24-year-old man underwent percutaneous renal biopsy because of an accidentally found proteinuria. Electron microscopy of his renal biopsy showed numerous electron-dense multi-lamellar inclusions in the epithelial cytoplasm, typical for Fabry disease. Clinical and laboratory evaluation including the assessment of GLA enzyme activity and direct DNA sequencing in four members of the family were performed. Renal biopsy findings in the two affected male patients were described. Re-evaluation of a renal biopsy specimen of his 28-year-old brother obtained when he was diagnosed with renal failure revealed a very focal area of suspicious multilamellated structures in the Bowman's space. DNA sequencing on the young man, his brother, and his mother revealed a novel GLA gene mutation, c.263A > G (p.Tyr88Cys). The three all showed decreased α-galactosidase A activity. CONCLUSION: A novel GLA mutation, c.263A > G (p.Tyr88Cys), was found in a Korean family with predominant renal manifestations of Fabry disease.

Serum gamma-glutamyltransferase is not associated with subclinical atherosclerosis in patients with type 2 diabetes.

BACKGROUND: This study investigated the association between serum gamma-glutamyltransferase (GGT) level and subclinical atherosclerosis in patients with type 2 diabetes. METHODS: This cross-sectional study involved 1024 patients with type 2 diabetes mellitus. Measurement of brachial-ankle pulse wave velocity (baPWV; as a marker of arterial stiffness) and an ultrasound assessment of carotid atherosclerosis were performed. Subclinical atherosclerosis was defined by the presence of a high baPWV (≥1720 cm/s), carotid atherosclerosis (intima-media thickness >0.8 mm or the presence of plaques), and carotid stenosis (≥50 % of luminal narrowing). The subjects were stratified into quartiles according to GGT level, and the relationship between GGT level and subclinical atherosclerosis was analysed. RESULTS: Serum GGT levels were closely associated with obesity, atherogenic dyslipidemia, and metabolic syndrome. However, serum GGT levels did not show a linear association with baPWV, carotid intima-media thickness, or plaque grade. The prevalence of high baPWV, carotid atherosclerosis, and carotid stenosis did not differ between the quartiles in men and women. Multivariate logistic regression analyses revealed no association between GGT level and high baPWV, carotid atherosclerosis, and carotid stenosis, either as continuous variables or quartiles. CONCLUSIONS: Serum GGT levels were significantly associated with obesity, atherogenic dyslipidaemia, and metabolic syndrome, but not with the early and late stages of atherosclerotic vascular changes, in patients with type 2 diabetes. Serum GGT level may not be a reliable marker of subclinical atherosclerosis in type 2 diabetes.

Overhydration Negatively Affects Quality of Life in Peritoneal Dialysis Patients: Evidence from a Prospective Observational Study.

UNLABELLED: Backgound: This study evaluated whether the hydration status affected health-related quality of life (HRQOL) during 12 months in peritoneal dialysis (PD) patients. METHODS: The hydration status and the HRQOL were examined at baseline and after 12 months using a bioimpedance spectroscopy and Kidney Disease Quality of Life-Short Form, respectively in PD patients. Four hundred eighty-one patients were included and divided according to the baseline overhydration (OH) value; normohydration group (NH group, -2L≤ OH ≤+2L, n=266) and overhydration group (OH group, OH >+2L, n=215). Baseline HRQOL scores were compared between the two groups. The subjects were re-stratified into quartiles according to the OH difference (OH value at baseline - OH value at 12 months; <-1, -1 - -0.1, -0.1 - +1, and ≥+1L). The relations of OH difference with HRQOL scores at 12 months and the association of OH difference with the HRQOL score difference (HRQOL score at baseline - HRQOL score at 12 months) were assessed. RESULTS: The OH group showed significantly lower baseline physical and mental health scores (PCS and MCS), and kidney disease component scores (KDCS) compared with the NH group (all, P<0.01). At 12 months, the adjusted PCS, MCS, and KDCS significantly increased as the OH difference quartiles increased (P<0.001, P=0.002, P<0.001, respectively). In multivariate analysis, the OH difference was independently associated with higher PCS (ß = 2.04, P< .001), MCS (ß=1.02, P=0.002), and KDCS (ß=1.06, P<0.001) at 12 months. The OH difference was independently associated with the PCS difference (ß = -1.81, P<0.001), MCS difference (ß=-0.92, P=0.01), and KDCS difference (ß=-0.90, P=0.001). CONCLUSION: The hydration status was associated with HRQOL and increased hydration status negatively affected HRQOL after 12 months in PD patients.

Anthocyanin-rich Seoritae extract ameliorates renal lipotoxicity via activation of AMP-activated protein kinase in diabetic mice.

BACKGROUND: Anthocyanins are major constituents of food colours and have been reported to possess anti-diabetic activities for potential medicinal use. The precise role of anthocyanins in diabetic nephropathy is poorly understood. We investigated whether anthocyanin-rich Seoritae extract (SE) can potentially prevent oxidative stress and lipotoxicity, which are the main causes of renal damage in diabetic nephropathy, via activation of AMP-activated protein kinase (AMPK) and the consequent effects on its target molecules. METHODS: Four groups of male C57BLKS/J db/m and db/db mice were used. Diabetic and non-diabetic mice were orally administered 10 mg/kg body weight SE daily for 12 weeks, starting at 8 weeks of age. RESULTS: db/db mice treated with anthocyanins showed decreased albuminuria. Anthocyanins ameliorated intra-renal lipid concentrations in db/db mice with improvement of glomerular matrix expansion and inflammation, which was related to increased phosphorylation of AMPK and activation of peroxisome proliferator-activated receptor (PPAR) α and PPARγ, and inhibited the activity of acetyl-CoA carboxylase and sterol regulatory element-binding protein 1. Anthocyanins reversed diabetes-induced increases in renal apoptosis and oxidative stress. In cultured human glomerular endothelial cells, anthocyanins prevented high glucose-induced oxidative stress and apoptosis through activation of AMPK in the same manner. CONCLUSIONS: The results revealed that anthocyanins ameliorated diabetic nephropathy in db/db mice via phosphorylation of AMPK, the major energy-sensing enzyme, and the consequent effects on its target molecules, which appeared to prevent lipotoxicity-related apoptosis and oxidative stress in the kidney.

Fimasartan, a Novel Angiotensin-Receptor Blocker, Protects against Renal Inflammation and Fibrosis in Mice with Unilateral Ureteral Obstruction: the Possible Role of Nrf2.

OBJECTIVES: A newly developed angiotensin II receptor blocker, fimasartan, is effective in lowering blood pressure through its action on the renin-angiotensin system. Renal interstitial fibrosis, believed to be due to oxidative injury, is an end-stage process in the progression of chronic kidney disease. Nuclear factor erythroid 2-related factor 2 (Nrf2) is known to regulate cellular oxidative stress and induce expression of antioxidant genes. In this study we investigated the role of Nrf2 in fimasartan-mediated antioxidant effects in mice with renal fibrosis induced by unilateral ureteral obstruction (UUO). MATERIALS AND METHODS: UUO was induced surgically in mice, followed by either no treatment with fimasartan or the intraperitoneal administration of fimasartan (3 mg/kg/day). On day 7, we evaluated the changes in the renin-angiotensin system (RAS) and the expression of Nrf2 and its downstream antioxidant genes, as well as renal inflammation, apoptosis, and fibrosis in the obstructed kidneys. The effect of fimasartan on the Nrf2 pathway was also investigated in HK-2 cells stimulated by tumor necrosis factor-α. RESULTS: The mice with surgically induced UUO showed increased renal inflammation and fibrosis as evidenced by histopathologic findings and total collagen content in the kidney. These effects were attenuated in the obstructed kidneys of the fimasartan-treated mice. Fimasartan treatment inhibited RAS activation and the expression of Nox1, Nox2, and Nox4. In contrast, fimasartan upregulated the renal expression of Nrf2 and its downstream signaling molecules (such as NQO1; HO-1; GSTa2 and GSTm3). Furthermore, it increased the expression of antioxidant enzymes, including CuSOD, MnSOD, and catalase. The fimasartan-treated mice had significantly less apoptosis on TUNEL staining, with decreased levels of pro-apoptotic protein and increased levels of anti-apoptotic protein. In the HK-2 cells, fimasartan treatment inhibited RAS activation, decreased expression of mitogen-activated protein kinases (MAPKs), and upregulated the Nrf2 pathway. CONCLUSIONS: These results suggest that fimasartan has beneficial effects in reducing renal oxidative stress, inflammation, and fibrosis. Possible mechanisms to explain these effects are inhibition of RAS and MAPKs and upregulation of Nrf2 signaling, with subsequent induction of antioxidant pathways.

Delayed treatment with oleanolic acid attenuates tubulointerstitial fibrosis in chronic cyclosporine nephropathy through Nrf2/HO-1 signaling.

BACKGROUND: Nuclear factor erythroid-2-related factor-2 (Nrf2) is known to protect against tissue injury by orchestrating antioxidant and detoxification responses to oxidative stress. This study investigated whether upregulation of Nrf2-dependent signaling by oleanolic acid (OA), which is known to activate Nrf2, could attenuate renal inflammation and fibrosis in cyclosporine (CsA)-induced kidney injury. METHODS: Male ICR mice were divided into four treatment groups: Vehicle (VH, n = 6), VH + OA (n = 6), CsA (n = 8), and CsA + OA (n = 8). For the OA-treated groups, OA (25 mg/kg/day) was administered by intraperitoneal injection for the final week of the 4-week experimental period. Renal function, morphologies and signaling were evaluated at the end of the study. RESULTS: Treatment with CsA resulted in decreased kidney function and urine osmolality and increased urine volume and urinary albumin levels. The CsA-induced changes were improved by OA treatment. Specifically, administration of OA decreased tubulointerstitial fibrosis and inflammation scores that were increased in CsA-treated mice. Furthermore, OA treatment decreased urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG) and 8-epi-prostaglandin F2α (8-iso-PGF2α) levels. The beneficial effects of OA were attributed to an increased ratio of nuclear/total Nrf2 and subsequently enhanced expression of heme oxygenase (HO)-1, as well as a stable level of Kelch-like ECH-associated protein 1 (Keap1) expression, indicating that OA enhanced nuclear translocation of Nrf2. Increased apoptotic cell death and a high ratio of B cell leukaemia/lymphoma 2 (Bcl-2)-associated X protein (Bax) to Bcl-2 in CsA-treated mice were also significantly ameliorated by OA treatment. CONCLUSION: Our results suggest that OA activates Nrf2/HO-1 signaling in chronic CsA nephropathy, which may have beneficial effects on inflammation and oxidative stress.

Association of blood manganese level with diabetes and renal dysfunction: a cross-sectional study of the Korean general population.

BACKGROUND: The purpose of this study was to evaluate the association between blood manganese levels and the prevalence of chronic diseases in the Korean population. METHODS: This was a cross-sectional study based on the Korean National Health and Nutrition Examination Survey (KNAHNES). The study included 3996 participants 20 years of age or older whose blood manganese levels had been measured. The participants were also evaluated for the presence of five chronic diseases: diabetes, renal dysfunction, hypertension, ischemic heart disease, and stroke. RESULTS: Blood manganese levels were significantly lower in the diabetes group compared with the non-diabetes group (1.26 ± 0.02 vs. 1.35 ± 0.01 µg/dL; p = 0.001) and the renal dysfunction group compared with those with normal renal function (1.28 ± 0.03 vs. 1.35 ± 0.01 µg/dL; p = 0.04). There was no significant association between blood manganese levels and the presence of ischemic heart disease or stroke. A multivariate logistic regression analysis adjusted for age, sex, and body mass index was performed; the odds ratio was 0.652 (95% CI: 0.46-0.92) for diabetes and 0.589 (95% CI: 0.39-0.88) for renal dysfunction when comparing the higher quartiles (Q2-4) with the lowest quartile (Q1) of blood manganese level. The prevalence of diabetes was 7.6% in Q1 and 5.3% in Q2-4 (p = 0.02). Similarly, the prevalence of renal dysfunction was 6.8% in Q1, compared with 4.6% in Q2-4 (p = 0.02). CONCLUSION: The prevalence of diabetes and renal dysfunction increased in participants with low blood manganese levels, suggesting that blood manganese may play a role in glucose homeostasis and renal function.

Blood lead and cadmium levels and renal function in Korean adults.

BACKGROUND: The objective of this study was to evaluate the associations of blood lead and cadmium levels with estimated glomerular filtration rate (eGFR) and proteinuria in Korean adults. METHODS: This was a cross-sectional study based on the Korea Nation Health and Nutrition Examination Survey (KNHANES) to analyze the association of blood lead and cadmium levels with renal dysfunction and urine protein excretion. We defined renal dysfunction as eGFR < 60 ml/min/1.73 m(2), as measured by the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation and proteinuria as positive urine dip-stick result. RESULTS: Blood lead and cadmium levels were significantly increased in the renal dysfunction group compared with the normal renal function group. Lead levels were significantly higher in the proteinuria group than in the group with no proteinuria. There were no differences in cadmium levels according to the amount of proteinuria. Multivariate logistic regression analysis adjusted for age and sex demonstrated higher lead and cadmium levels in the renal dysfunction group than in the group with normal renal function [odds ratio (OR) 1.344, 95 % confidence interval (CI) 1.157-1.162, P < 0.05; OR 1.467, 95 % CI 1.077-1.999, P < 0.05, respectively]. For proteinuria, the fully adjusted ORs comparing the highest versus the lowest lead and cadmium quartiles were 1.22 (95 % CI 1.00-1.50) and 0.51 (95 % CI 0.24-1.08), respectively, showing no significance. For reduced eGFR, the fully adjusted ORs comparing the highest versus the lowest lead and cadmium quartiles were 1.23 (95 % CI 0.98-1.53) and 1.93 (95 % CI 1.39-2.67), respectively, showing the significant association between lead and cadmium levels and renal function. The risk of having reduced eGFR for individuals in the highest quartiles of both lead and cadmium levels in blood was greater than for those in the highest quartile of blood level of lead or cadmium only. CONCLUSION: The CKD-EPI equation showed that blood lead and cadmium levels were associated with renal dysfunction in the Korean adult population. This finding has significant implications for environmental institutional strategies regarding heavy metal exposure.

Safety and tissue yield for percutaneous native kidney biopsy according to practitioner and ultrasound technique.

BACKGROUND: Although percutaneous renal biopsy remains an essential tool in the diagnosis and treatment of renal diseases, in recent times the traditional procedure of nephrologists has been performed by non-nephrologists rather than nephrologists at many institutions. The present study assessed the safety and adequacy of tissue yield during percutaneous renal biopsy according to practitioners and techniques based on ultrasound. METHODS: This study included 658 native renal biopsies performed from 2005 to 2010 at a single centre. The biopsies were performed by nephrologists or expert ultrasound radiologists using the ultrasound-marked blind or real-time ultrasound-guided techniques. RESULTS: A total of 271 ultrasound-marked blind biopsies were performed by nephrologists, 170 real-time ultrasound-guided biopsies were performed by nephrologists, and 217 real-time ultrasound-guided biopsies were performed by radiologists during the study period. No differences in post-biopsy complications such as haematoma, need for transfusion and intervention, gross haematuria, pain, or infection were observed among groups. Glomerular numbers of renal specimens from biopsies performed by nephrologists without reference to any technique were higher than those obtained from real-time ultrasound-guided biopsies performed by expert ultrasound radiologists. CONCLUSIONS: Percutaneous renal biopsy performed by nephrologists was not inferior to that performed by expert ultrasound radiologists as related to specimen yield and post-biopsy complications.