Absolute iron deficiency, coronary artery calcification and cardiovascular mortality in maintenance haemodialysis patients.

AIM: The effects of iron on vascular calcification in rats and vascular smooth muscle cells were recently reported, but clinical studies on iron and vascular calcification are scant. We studied the associations of absolute iron deficiency, coronary artery calcification and mortality in patients with maintenance haemodialysis (MHD). METHODS: Transferrin saturation (TSAT), ferritin, mean corpuscular haemoglobin (MCH) and Agatston coronary artery calcium score (CACS) were studied at baseline in MHD patients and followed up for 3 years. Cox proportional hazard analyses for mortality and linear regression analyses for CACS were performed. RESULTS: In 306 patients, the median age was 67 (56-81) years, dialysis duration was 76 (38-142) months, and diabetes prevalence was 42.5%. Fifty-two patients had died by 3 years. Patients with absolute iron deficiency (TSAT <20% and ferritin <100 ng/mL) (n = 102) showed significantly higher CACS (p = .0266) and C-reactive protein (p = .0011), but a lower frequency of iron formulation administration compared with patients without absolute iron deficiency at baseline (n = 204). Absolute iron deficiency was a significant predictor for 3-year cardiovascular (CV) mortality (hazard ratio: 2.08; p = .0466), but not for 3-year all-cause mortality. CACS was significant predictor for both 3-year CV and all-cause mortality (p <.05). Absolute iron deficiency and MCH were significant determinants of CACS (p < .05). CONCLUSION: MHD patients with absolute iron deficiency showed significantly higher CACS than others, and absolute iron deficiency was a significant risk factor for coronary artery calcification and 3-year CV mortality in MHD patients, but was not a significant predictor for 3-year all-cause mortality.

Effects of overhydration, Kt/Vurea, ß2-microglobulin on coronary artery calcification and mortality in haemodialysis patients.

AIM: We studied the effects of overhydration (OH), Kt/Vurea and ß2-microglobulin (ß2-MG) on coronary artery calcification and mortality in patients undergoing haemodialysis (HD). METHODS: The Agatston coronary artery calcium score (CACS), postdialysis body composition using bioimpedance analysis, single-pool Kt/Vurea and predialysis ß2-MG at baseline were assessed and followed up for 3 years in patients undergoing HD. We performed logistic regression analyses for a CACS ≥400 and Cox proportional hazard analyses for all-cause and cardiovascular mortality. RESULTS: The study involved 338 patients with a median age of 67 (56-74) years, dialysis duration of 70 (33-141) months and diabetes prevalence of 39.1% (132/338). Patients with a CACS ≥400 (n = 222) had significantly higher age, dialysis duration, male prevalence, diabetes prevalence, C-reactive protein, predialysis ß2-MG, OH, extracellular water/total body water and overhydration/extracellular water (OH/ECW) but significantly lower Kt/Vurea than patients with a CACS <400 (n = 116) (p < .05). OH/ECW, Kt/Vurea and predialysis ß2-MG were significant predictors of a CACS ≥400 (p < .05) after adjusting for age, dialysis duration, serum phosphate and magnesium. In all patients, cut-off values of OH/ECW, Kt/Vurea and predialysis ß2-MG for a CACS ≥400 were 16%, 1.74 and 28 mg/L, respectively. After adjusting for dialysis duration, OH/ECW ≥16%, Kt/Vurea ≥1.74 and ß2-MG ≥28 mg/L were significant predictors of 3-year all-cause mortality but not 3-year cardiovascular mortality. CONCLUSION: Higher OH/ECW, higher predialysis ß2-MG and lower Kt/Vurea values are significant risk factors for a CACS ≥400 and 3-year all-cause mortality in patients undergoing maintenance HD.

α1- and ß2-Microglobulin reduction ratios and survival in patients on predilution online haemodiafiltration.

AIM: ß2-Microglobulin (ß2-MG) and α1-microglobulin (α1-MG) have molecular weights of 11,800 and 33,000 Da, respectively. We studied the α1-MG and ß2-MG reduction ratios (RRs) and survival in patients on predilution online haemodiafiltration (Pre-OL-HDF). METHODS: Participants were 247 Pre-OL-HDF patients. α1-MG and ß2-MG RRs were assessed at baseline. Kaplan-Meier survival and Cox proportional hazard analyses were used. RESULTS: In 247 patients, the median age was 67 (56-73) years, the dialysis duration was 77 (46-150) months, and the diabetes prevalence was 47.4%. Twenty-two patients died over the 450-day study period. The mortality cut-off values using receiver-operating characteristic curves for the α1-MG and ß2-MG RRs were 20% and 80%, respectively. Survival rates were significantly (p < 0.05) higher in patients with α1-MG RRs ≥20% (n = 134) compared with patients with α1-MG RRs <20% (n = 113) and in patients with ß2-MG RRs ≥80% (n = 87) compared with patients with ß2-MG RRs <80% (n = 160). Cox models adjusting for diabetes and dialysis duration showed that α1-MG RR, ß2-MG RR, and pre- and postdialysis ß2-MG were risk factors for all-cause mortality; however, after additional adjustment for age, sex, and serum albumin, only ß2-MG RR and pre- and postdialysis ß2-MG were significant predictors of mortality (p < 0.05). α1-MG RRs were significantly correlated with ß2-MG RRs (ρ = 0.73, p < 0.0001) and serum albumin levels (ρ = 0.13, p < 0.05). CONCLUSION: In patients on Pre-OL-HDF, α1-MG RRs ≥20% and ß2-MG RRs ≥80% were associated with better survival, ß2-MG RR ≥80% and pre-and postdialysis ß2-MG levels were significant predictors of all-cause mortality, and α1-MG RR ≥20% may predict mortality.

Utility of CHA2DS2-VASc Score to Predict Mid-Term Clinical Outcomes in Hemodialysis Patients.

BACKGROUND: The CHA2DS2-VASc score has been widely used to predict stroke in patients with atrial fibrillation (AF). Recently, it was reported that the CHA2DS2-VASc score helps predict cardiovascular disease (CVD) or all-cause mortality in patients with or without AF. However, few reports have examined the association between this score and mortality in hemodialysis (HD) patients. METHODS: We analyzed 557 consecutive patients who initiated HD at our facilities between February 2005 and October 2017. The CHA2DS2-VASc score was calculated at the time of initiation of HD. Patients were then categorized into three groups according to their CHA2DS2-VASc scores: 0-1 (low), 2-3 (intermediate), and 4-9 (high). Multivariate Cox proportional hazards analysis was used to assess independent risk factors for 3-year all-cause mortality. RESULTS: During the 3-year follow-up period, 153 (27.5%) patients died (cardiovascular death: n = 88). According to multivariate analysis, serum albumin (hazard ratio [HR] 0.60, 95% confidence interval [CI] 0.43-0.85, p = 0.003), creatinine (HR 0.91, 95% CI 0.84-0.99, p = 0.049), and CHA2DS2-VASc score (HR 1.33, 95% CI 1.20-1.46, p < 0.001) were associated with 3-year all-cause mortality. Compared with patients in the low CHA2DS2-VASc score group, those in the intermediate- and high-score groups had a higher risk for all-cause and CVD mortality (all-cause mortality: HR 1.77, 95% CI 1.23-2.55, p = 0.002 and HR 2.94, 95% CI 1.90-4.53, p < 0.001, respectively; CVD mortality: HR 1.82, 95% CI 1.27-2.59, p = 0.001 and HR 2.85, 95% CI 1.88-4.31, p < 0.001, respectively). CONCLUSION: The CHA2DS2-VASc score is a valuable predictor of 3-year all-cause and CVD mortality in incident HD patients.

Relationships of hyperchloremia with hypertension and proteinuria in patients with chronic kidney disease.

BACKGROUND: A few previous clinical studies have shown that chloride (Cl) contributes to the progression and development of hypertension or proteinuria. Therefore, we aimed to determine whether hyperchloremia is associated with hypertension or proteinuria in patients with chronic kidney disease (CKD) and to define the relationships between the reduction in serum Cl concentration associated with CKD treatment and improvements in hypertension and/or proteinuria. METHODS: We performed a retrospective observational study of new or referred patients with CKD who had hyperchloremia, moderate proteinuria, renal dysfunction, and hypertension. Patients taking medication for metabolic acidosis or with a history of dialysis were excluded. The participants' systolic and diastolic blood pressure (BP), serum sodium (Na) and Cl concentrations, and urinary protein (UP) concentration were measured at baseline and after 1 month of CKD treatment. RESULTS: Fifty-one patients with CKD were included in the study. Their serum Cl concentration independently correlated with sBP and UP at baseline (P = 0.022 and P = 0.033, respectively). After 1 month's CKD treatment, their serum Na and Cl concentrations, sBP, and UP were significantly lower. The change in sBP during the month (ΔsBP) correlated with the change in serum Cl (ΔCl) (P = 0.012) but not with the change in serum Na. Multivariate analysis showed that ΔsBP was independently associated with ΔCl (P = 0.029). CONCLUSIONS: Hyperchloremia is an independent predictor of hypertension and proteinuria for patients with CKD.

Convection volume, ß2-microglobulin and α1-microglobulin reduction ratios, and body composition in pre-dilution online haemodiafiltration.

AIM: The effect of convection volume (CV) in patients on pre-dilution online haemodiafiltration (Pre-OL-HDF) was evaluated. METHODS: We conducted a retrospective, cross-sectional study in 126 patients on Pre-OL-HDF. Dialysis conditions, laboratory data, and same day post-dialysis body composition measurements using bioimpedance spectroscopy were assessed. Patients were divided into two groups according to their CV: ≥ median value and < median value. Linear regression analyses for reduction ratios (RRs) of ß2-microglobulin and α1-microglobulin, and body composition, were conducted. RESULTS: Age, dialysis vintage, and CVs of the study patients were 64 ± 12 years, 81 (48-154) months, and 43.2 (38.5-55.9) L/session, respectively. The higher CV (≥ 43 L/session) group (n = 66) had significantly higher RRs of ß2-microglobulin and α1-microglobulin, lean tissue index, body cell mass index, total body water (TBW), extracellular water (ECW), and intracellular water (ICW) compared with the lower CV (< 43 L/session) group (n = 60, p <  .01). Serum albumin and fat tissue index were not significantly different between the groups. CV/ECW, CV/TBW, and CV/ICW but not un-adjusted CV, were significant determinants for ß2-microglobulin and α1-microglobulin RRs (p <  .05). Lean tissue and body cell mass indexes, but not the fat tissue index, showed significant associations with CV, and RRs of ß2-microglobulin and α1-microglobulin (p < kb.05). CONCLUSIONS: Among patients on Pre-OL-HDF, higher values in the lean tissue index and body cell mass index were observed in those with higher CV versus lower CV, and CV adjusted to body water may be useful to prescribe individualized conditions for Pre-OL-HDF.

A case report of atypical anti-glomerular basement membrane disease.

BACKGROUND: Anti-glomerular basement membrane (anti-GBM) disease is characterized by crescentic necrotizing glomerulonephritis, with linear deposits of immunoglobulin G (IgG) in the GBM. Classic anti-GBM disease is clinically associated with rapidly progressive glomerulonephritis with or without pulmonary hemorrhage. Some patients have a better renal prognosis and milder symptoms than those with classic anti-GBM disease, which is termed atypical anti-GBM disease. CASE PRESENTATION: A 43-year-old Japanese woman was admitted to our hospital complaining of hematuria that had persisted for more than one month. Serological examination revealed negativity for anti-nuclear, anti-neutrophilic cytoplasmic, and anti-GBM antibodies. However, renal biopsy showed cellular crescents. Immunofluorescence revealed strong diffuse linear capillary loop staining for IgG. An indirect immunofluorescence antibody method was performed by applying the patient serum to normal kidney tissue to confirm the presence of autoantibodies binding to the GBM. Using this method, anti-GBM antibodies were detected. The patient was treated with high-dose steroids, cyclophosphamide, and plasma exchange. Aggressive treatment resolved proteinuria and hematuria and improved renal function. CONCLUSIONS: Renal biopsy is crucial in the diagnosis of anti-GBM disease, especially when serological tests are negative. Accurately identifying the presence of anti-GBM disease is important to initiate optimal treatment.

Klotho overexpression protects against renal aging along with suppression of transforming growth factor-ß1 signaling pathways.

Klotho is an antiaging protein reported to suppress transforming growth factor-ß1 (TGF-ß1) signaling. Aging kidneys are characterized by interstitial fibrosis, accumulation of cell cycle-arrested cells, and increased levels of oxidative stress. TGF-ß1 signaling is involved in these processes. In this study, we investigated whether klotho overexpression improves these features in the kidneys of aging mice and examined the inhibitory effect of klotho on signaling molecules related to transforming growth of TGF-ß1. Klotho transgenic (KLTG) and wild-type (WT) mice were used, and 8-wk-old and 24-mo-old mice were defined as young and aging, respectively. We found that klotho expression was decreased in aging WT mice, but it was maintained in aging KLTG mice. Klotho overexpression improved the survival of 24-mo-old mice. Although the serum Ca2+ level was significantly lower in aging KLTG mice than in aging WT mice, the serum phosphate level did not differ between these mice. Klotho overexpression attenuated the increases in blood pressure, serum blood urea nitrogen level, and serum creatinine level in aging mice. Interstitial fibrosis, accumulation of cell cycle-arrested cells, and oxidative stress did not differ between young KLTG and WT mice, but they were significantly suppressed in aging KLTG mice compared with aging WT mice. Furthermore, the expression of TGF-ß1-related signaling molecules was increased in aging WT mice, whereas it was inhibited in aging KLTG mice. These data suggest that klotho overexpression protects against kidney aging along with suppression of TGF-ß1 signaling pathways.NEW & NOTEWORTHY Klotho is considered as an antiaging protein, and its overexpression may be a candidate therapy for protection against kidney damage with advanced aging. Although multiple factors are involved in the aging process, we showed that klotho overexpression inhibited interstitial fibrosis, accumulation of cell cycle-arrested cells, and increased levels of oxidative stress in the kidneys of aging mice, suppressing transforming growth factor-ß1-related signaling pathways. The present data showed that klotho overexpression protects against age-associated kidney damage.

Association and predictive value of geriatric nutritional risk index, body composition, or bone mineral density in haemodialysis patients.

AIM: Assess the association and predictive value of geriatric nutritional risk index (GNRI), body composition, and bone mineral density (BMD) in haemodialysis (HD) patients. METHODS: Laboratory data, body composition parameters measured via body composition monitor, and radius, lumbar spine, femoral neck BMD measured using dual energy X-ray absorptiometry were assessed in all subjects on HD or online haemodiafiltration (HDF) at baseline. Regression analysis for GNRI, Cox proportional hazard analyses and comparison of multiple receiver operating characteristic (ROC) curves were performed. RESULTS: Among all 264 patients, age was 65 ± 12 years and dialysis vintage was 79 (39-144) months. GNRI tertile (T)1, T2, and T3 were 88 (85-91), 94 (93-95), and 98 (97-101), respectively. Patients in GNRI T1 had lower fat tissue index (FTI), lean tissue index, and femoral neck, lumbar spine, and distal mid-third radius BMD, but higher overhydration/extracellular fluid than patients in GNRI T2 or T3 (P < .05). GNRI was significantly associated with FTI, lean tissue index, and femoral neck, lumbar spine, and distal mid-third radius BMD (P < .01). GNRI was a significant predictor of 2-year all-cause mortality (HR 0.92, P < .05). Area under the ROC curve for all-cause mortality using traditional risk factors (age, sex, diabetes mellitus, cardiovascular disease, use of vasopressors for dialysis-related hypotension, and C-reactive protein) was 0.67 and changed by adding GNRI (0.78, P < .05), FTI (0.75), or femoral neck BMD (0.66), respectively. CONCLUSION: Associations between GNRI, body composition, and BMD were confirmed in HD patients. Combining GNRI with traditional risk factors improved mortality prediction in HD patients.

Iron, coronary artery calcification, and mortality in patients undergoing hemodialysis.

OBJECTIVE: A high coronary artery calcification score (CACS) may be associated with high mortality in patients undergoing hemodialysis (HD). Recently, effects of iron on vascular smooth muscle cell calcification have been described. We aimed to investigate the relationships between iron, CACS, and mortality in HD patients. METHODS: We studied 173 consecutive patients who were undergoing maintenance HD. Laboratory data and Agatston's CACS were obtained at baseline for two groups of patients: those with CACS ≥400 (n = 109) and those with CACS <400 (n = 64). Logistic regression analyses for CACS ≥400 and Cox proportional hazard analyses for mortality were conducted. RESULTS: The median (interquartile range) age and duration of dialysis of the participants were 67 (60-75) years and 73 (37-138) months, respectively. Serum iron (Fe) and transferrin saturation (TSAT) levels were significantly lower in participants with CACS ≥400 than in those with CACS <400, although the serum ferritin concentration did not differ between the groups. TSAT ≥21% was significantly associated with CACS ≥400 (odds ratio 0.46, p<0.05). TSAT ≥17%, Fe ≥63 µg/dL, and ferritin ≥200 ng/mL appear to protect against 5-year all-cause mortality in HD patients, independent of conventional risk factors of all-cause mortality (p < 0.05). CONCLUSION: We have identified associations between iron, CACS, and mortality in HD patients. Lower TSAT was found to be an independent predictor of CACS ≥400, and iron deficiency (low TSAT, iron, or ferritin) was a significant predictor of 5-year all-cause mortality in HD patients.

Finite-temperature-based time-dependent density-functional theory method for static electron correlation systems.

In this study, we developed a time-dependent density-functional theory (TDDFT) with a finite-temperature (FT) scheme, denoted as FT-TDDFT. We introduced the concept of fractional occupation numbers for random phase approximation equation and evaluated the excited-state electronic entropy terms with excited-state occupation number. The orbital occupation numbers for the excited state were evaluated from the change in the ground-state electron configuration with excitation and deexcitation coefficients. Furthermore, we extended the FT formulation to the time-dependent density-functional tight-binding (TDDFTB) method for larger systems, denoted as FT-TDDFTB. Numerical assessment for the FT-(TD)DFT method showed smooth potential curves for double-bond rotation of ethylene in both ground and excited states. Excited-state calculations based on the FT-TDDFTB method were applied to the uniform π-stacking columns composed of trioxotriangulene, possessing neutral radicals in strong correlation systems.

High-normal albuminuria is strongly associated with incident chronic kidney disease in a nondiabetic population with normal range of albuminuria and normal kidney function.

BACKGROUND: Albuminuria and estimated glomerular filtration rate (eGFR) are clinically measured to evaluate the severity of chronic kidney disease (CKD). The aim of our study was to clarify the association between clinical parameters, including albuminuria and eGFR, and the risk of incident CKD in a nondiabetic population with normal range of albuminuria and eGFR. METHODS: A 10-year follow-up, retrospective cohort study involving 317 Japanese men (mean age, 42 years) with eGFR ≥ 90 mL/min/1.73 m2 and urine albumin-to-creatinine ratio (UACR) < 30 mg/gCr was performed. Participants were free of diabetes mellitus. Multivariate logistic regression approaches were used to assess independent predictors of the incidence of CKD. RESULTS: Twenty-nine (9%) participants developed CKD (eGFR < 60 mL/min/1.73 m2 and/or UACR ≥ 30 mg/gCr) through 10 years of follow-up. At the baseline examination, age, blood pressure, UACR, and eGFR were higher in participants who developed CKD than in those without CKD. After adjustment for confounders, high-normal albuminuria (P < 0.001) and hypertension (P = 0.045) were associated with an increased incidence of CKD. From receiver-operating characteristic curves, UACR ≥ 7.0 mg/gCr was defined as high-normal albuminuria. Logistic regression analysis also showed that, in addition to presence of hypertension, UACR ≥ 7.0 mg/gCr was identified as an independent risk of incident CKD within 10 years after adjustment for age, body mass index, smoking status, and dyslipidemia [UACR: odds ratio (OR) 17.36 (95% CI 6.16-48.93, P < 0.001)]. CONCLUSION: High-normal albuminuria and hypertension are associated with incident CKD in a nondiabetic population with normal-range UACR and eGFR.

A case report of adult-onset COQ8B nephropathy presenting focal segmental glomerulosclerosis with granular swollen podocytes.

BACKGROUND: Primary coenzyme Q10 (CoQ10) deficiency of genetic origin is one of a few treatable focal segmental glomerulosclerosis (FSGS). Renal morphologic evidence for COQ8B mutation and CoQ10 deficiencies of other gene mutations is assessed using electron microscopy with marked increase of abnormal-shaped mitochondria in podocytes. However, light microscopic morphologic features of deficiencies other than FSGS have not been reported. CASE PRESENTATION: A 30-year-old woman was admitted to our hospital because proteinuria was found during four consecutive medical checkups. She had no medical history or family history of proteinuria and severe renal dysfunction. The swollen podocytes were stained to the same extent as mitochondria-rich proximal tubular cells under both Masson's trichrome and hematoxylin-eosin staining, whereas no mitochondrial abnormalities were detected under the first electron microscopic views. As proteinuria and estimated glomerular filtration rate (eGFR) deteriorated after pregnancy, we reevaluated the additional electron microscopic views and detected mitochondrial abnormalities. Genetic testing revealed COQ8B mutation (c.532C > T, p.R178W); therefore, we diagnosed COQ8B nephropathy. CoQ10 supplementation improved proteinuria and stopped eGFR reduction. CONCLUSIONS: This is the first report of granular swollen podocytes due to mitochondrial diseases detected under light microscopy. We propose that this finding can be the clue for the diagnosis of both COQ8B nephropathy and the other CoQ10 deficiencies.

Inhibition of the H3K4 methyltransferase MLL1/WDR5 complex attenuates renal senescence in ischemia reperfusion mice by reduction of p16INK4a.

Renal function declines with aging and is pathologically characterized by chronic inflammation and fibrosis. Renal senescence is induced not only by aging but also by various stimuli, including ischemia reperfusion injury. Recently, the accumulation of p16INK4a-positive cells in the kidney has been considered a molecular feature of renal senescence, with the p16INK4a gene reportedly regulated by mixed-lineage leukemia 1 (MLL1)/WD-40 repeat protein 5 (WDR5)-mediated histone 3 lysine 4 trimethylation (H3K4me3). Here, we determined whether inhibition of MLL1/WDR5 activity attenuates renal senescence, inflammation, and fibrosis in mice with ischemia reperfusion injury and in cultured rat renal fibroblasts. MM-102 or OICR-9429, both MLL1/WDR5 protein-protein interaction inhibitors, and small interfering RNA (siRNA) for MLL1 or WDR5 suppressed the expression of p16INK4a in mice with ischemia reperfusion injury, accompanied by downregulation of H3K4me3 expression. MM-102 attenuated renal fibrosis and inflammation in the kidney of mice with ischemia reperfusion injury. Moreover, in vitro study showed that transforming growth factor-ß1 induced the expression of MLL1, WDR5, H3K4me3, and p16INK4a. Finally, chromatin immunoprecipitation identified the p16INK4a promoter at an H3K4me3 site in renal fibroblasts. Thus, our findings show that H3K4me3 inhibition ameliorates ischemia reperfusion-induced renal senescence along with fibrosis and inflammation.

Na+-Cl- cotransporter-mediated chloride uptake contributes to hypertension and renal damage in aldosterone-infused rats.

Recently, in addition to epithelial sodium channel alpha-subunit (αENaC), the thiazide-sensitive sodium-chloride cotransporter (NCC) and pendrin, also known as sodium-independent chloride/iodide transporter, were reported to be activated by aldosterone. Here, we investigated whether chloride (Cl-) is responsible for hypertension, inflammation, and renal damage in aldosterone-infused rats. Following left nephrectomy, 8-wk-old male Sprague-Dawley rats were allocated into four groups: 1) drinking 1.0% sodium chloride solution with aldosterone infusion (Aldo/NaCl rats); 2) drinking 1.44% sodium bicarbonate solution with aldosterone infusion (Aldo/NaHCO3 rats); 3) drinking distilled water with aldosterone infusion (Aldo/water rats); and 4) drinking distilled water without aldosterone infusion (sham rats). Additionally, heminephrectomized rats with aldosterone infusion were fed a 0.26% NaCl diet (control); 8.0% NaCl diet (high-Na/high-Cl); or a 4.0% NaCl 6.67% sodium citrate diet (high-Na/half-Cl). Last, Aldo/NaCl rats were treated with or without hydrochlorothiazide. Blood pressure in the Aldo/NaCl rats was significantly higher than in the Aldo/NaHCO3 rats, which was associated with the increased expression of NCC. Expression of markers of inflammation (CD3, CD68, interleukin-17A) and fibrosis (α-smooth muscle actin, collagen 1) were also increased in Aldo/NaCl rats. Similarly, aldosterone-infused rats fed a high-Na/half-Cl diet had lower blood pressure than those fed a high-Na/high-Cl diet, with a reduction of phosphorylated NCC, but not αENaC and pendrin. NCC inhibition with hydrochlorothiazide attenuated interleukin-17A protein expression along with the phosphorylation of NCC in Aldo/NaCl rats. These findings suggest that NCC-mediated Cl- uptake plays important roles in the development of aldosterone-induced hypertension and renal injury.

Valproic acid attenuates renal fibrosis through the induction of autophagy.

BACKGROUND: Renal fibrosis is a common pathological feature of the progression of chronic kidney disease. Although valproic acid (VPA) has been recently shown to induce autophagy, the effect of VPA-induced autophagy on renal fibrosis remains unknown. We, therefore, investigated whether VPA-induced autophagy suppresses renal fibrosis in a mouse model of unilateral ureteral obstruction (UUO). METHODS: Male C57BL/6 mice were divided into five groups (n = 8 per group): (1) sham group; (2) vehicle group; (3) VPA-treated group; (4) 3-methyladenine (3-MA; autophagy inhibitor)-treated group; and (5) VPA plus 3-MA-treated group. Mice underwent UUO and the kidneys were studied after 5 days. We also investigated the effect of VPA-induced autophagy on α-smooth muscle actin (α-SMA) in transforming growth factor (TGF)-ß1-stimulated rat kidney fibroblasts and epithelial cells. RESULTS: VPA attenuated renal fibrosis and induced autophagy in UUO mice, while 3-MA increased renal fibrosis and suppressed autophagy. In addition, the anti-fibrotic effect of VPA was diminished by 3-MA in UUO mice. In rat kidney fibroblasts and epithelial cells, VPA suppressed TGF-ß1-stimulated α-SMA expression and induced autophagy. In contrast, 3-MA enhanced α-SMA expression while inhibiting autophagy. Furthermore, the combined use of VPA and 3-MA treatments increased the expression of α-SMA compared with VPA treatment alone in TGF-ß1-stimulated rat kidney fibroblasts and epithelial cells, which was accompanied by the inhibition of autophagy. CONCLUSION: These findings suggest that VPA may be a candidate drug for the treatment of renal fibrosis through the induction of autophagy.

Inhibition of SET Domain-Containing Lysine Methyltransferase 7/9 Ameliorates Renal Fibrosis.

TGF-ß1 activity results in methylation of lysine 4 of histone H3 (H3K4) through SET domain-containing lysine methyltransferase 7/9 (SET7/9) induction, which is important for the transcriptional activation of fibrotic genes in vitro. However, in vivo studies utilizing an experimental model of renal fibrosis are required to develop therapeutic interventions that target SET7/9. In this study, we investigated the signaling pathway of TGF-ß1-induced SET7/9 expression and whether inhibition of SET7/9 suppresses renal fibrosis in unilateral ureteral obstruction (UUO) mice and kidney cell lines. Among the SET family, SET7/9 was upregulated on days 3 and 7 in UUO mice, and the upregulation was suppressed by TGF-ß1 neutralizing antibody. TGF-ß1 induced SET7/9 expression via Smad3 in normal rat kidney (NRK)-52E cells. In human kidney biopsy specimens from patients diagnosed with IgA nephropathy and membranous nephropathy, SET7/9 expression was positively correlated with the degree of interstitial fibrosis (r=0.59, P=0.001 in patients with IgA nephropathy; and r=0.58, P<0.05 in patients with membranous nephropathy). In addition, small interfering RNA-mediated knockdown of SET7/9 expression significantly attenuated renal fibrosis in UUO mice. Sinefungin, an inhibitor of SET7/9, also suppressed the expression of mesenchymal markers and extracellular matrix proteins and inhibited H3K4 mono-methylation (H3K4me1) in kidneys of UUO mice. Moreover, sinefungin had an inhibitory effect on TGF-ß1-induced α-smooth muscle actin expression and H3K4me1 in both NRK-52E and NRK-49F cells. In conclusion, sinefungin, a SET7/9 inhibitor, ameliorates renal fibrosis by inhibiting H3K4me1 and may be a candidate therapeutic agent.

Inhibition of H3K9 histone methyltransferase G9a attenuates renal fibrosis and retains klotho expression.

H3K9 methyltransferase G9a is reportedly induced by transforming growth factor-ß1 (TGF-ß1) and has an important role in the development of epithelial-mesenchymal transposition in cancer cells. Since the transcriptional activity of the Klotho gene is regulated by H3K9 modification, we investigated the effects of G9a on renal fibrosis and klotho expression. G9a levels were significantly upregulated by day 7 in the kidneys of unilateral ureteral-obstructed mice, but this was inhibited by TGF-ß1-neutralizing antibody. Administration of G9a small interfering RNA not only decreased α-smooth muscle actin and fibronectin but also increased klotho expression in the ureteral-obstructed mice. Similarly, intraperitoneal injection of BIX01294, a specific inhibitor of G9a, showed beneficial effects on renal fibrosis and klotho expression with decreased monomethylation of H3K9 (me1). In in vitro experiments, BIX01294 also inhibited TGF-ß1-induced fibrotic changes and klotho downregulation along with suppressed H3K9me1. In human kidney biopsy specimens, areas of G9a immunostaining correlated positively with H3K9me1 levels, as well as fibrotic markers, but correlated negatively with klotho expression. Thus, TGF-ß1-induced G9a has an important role in the progression of renal fibrosis and reduced klotho expression through H3K9me1.

High glucose promotes TGF-ß1 production by inducing FOS expression in human peritoneal mesothelial cells.

BACKGROUND: High glucose (HG) induces production of transforming growth factor-beta1 (TGF-ß1), but the mechanism remains elusive. The aim of this study was to determine the gene(s) involved in HG-induced TGF-ß1 production in human peritoneal mesothelial cells (HPMCs). METHODS: Microarray analysis was performed following a 3-h preincubation of HPMCs in 4 or 0.1% glucose medium. Transcriptional genes were selected using Gene Ontology analysis for biological processes, including regulation of transcription and DNA-dependent. The effects of small interfering RNA (siRNA) treatments on the up-regulation of TGF-ß1 mRNA were assessed by quantitative real-time polymerase chain reaction (qPCR). Finally, enzyme-linked immunosorbent assay (ELISA) was performed to determine which gene(s) contribute to the production of TGF-ß1 protein in the medium. RESULTS: Microarray analysis revealed that the expression of 51 genes increased by more than 3-fold. Gene ontology analysis identified 13 genes for further study. qPCR confirmed mRNA amplification for 9 of the 13 genes. Furthermore, HG-induced up-regulation of TGF-ß1 mRNA was attenuated by the siRNA of 4 genes: MDS1 and EVI1 complex locus (MECOM), FBJ murine osteosarcoma viral oncogene homolog B (FOSB), FBJ murine osteosarcoma viral oncogene homolog (FOS) and activating transcription factor 3 (ATF3). ELISA showed that siRNA treatment of FOS, but not MECOM, FOSB or ATF3, suppressed the increase of TGF-ß1 protein in the medium. CONCLUSIONS: FOS is a downstream effector of HG stimulation in HPMCs that contributes to TGF-ß1 production, suggesting that blocking FOS expression may be a therapeutic target for peritoneal fibrosis.

Expression of age-related factors during the development of renal damage in patients with IgA nephropathy.

BACKGROUND: Chronic kidney disease patients share clinical and pathological features with the general aging population. Increased oxidative DNA damage, accumulation of cell cycle-arrested cells and decreased Klotho expression are assumed to be age-related factors that are reportedly linked to kidney disease. This study sought to determine the association between these age-related factors and renal damage in patients with IgA nephropathy (IgAN). METHODS: We performed a cross-sectional analysis of 71 patients who were diagnosed with IgAN by renal biopsy. Expression of 8-hydroxydeoxyguanosine (8-OHdG, a marker of oxidative DNA damage), p16 (a marker of cell cycle-arrest) and Klotho (an anti-aging protein) were evaluated by immunohistochemical staining of renal biopsy samples. We correlated the changes in expression of these markers with Lee's pathologic grades and the Oxford classification. We also investigated the independent association between these markers and interstitial fibrosis using multiple linear regression analysis. RESULTS: 8-OHdG and p16 increased but Klotho decreased with progression of pathologic grade. Expression of 8-OHdG and p16 increased with the deterioration of mesangial hypercellularity and segmental glomerulosclerosis. In addition, p16 increased but Klotho decreased with progression of tubular atrophy/interstitial fibrosis. In univariate regression analysis, age, body mass index, systolic blood pressure, urinary protein excretion and expression of 8-OHdG, p16 and Klotho showed significant correlations with interstitial fibrosis. Multivariable regression analyses revealed that aging, increased renal expression of p16 and decreased expression of Klotho were independently correlated with interstitial fibrosis. CONCLUSIONS: The age-related factors might play important roles in the development of IgAN.