Drug-coated balloons versus drug-eluting stents for coronary de novo lesions in dialysis patients.

BACKGROUND: The aim of this study was to compare the efficacy of drug-coated balloon (DCB) angioplasty with drug-eluting stent (DES) angioplasty in the treatment of de novo coronary artery lesions in dialysis patients. METHOD: We retrospectively enrolled 400 consecutive dialysis patients with 464 coronary de novo lesions treated by DCB or DES from five participating institutions in Japan. The primary endpoint was target lesion revascularization (TLR) at 12 months. We performed serial coronary angiographic analysis. RESULTS: There were no significant differences in the rate of TLR between the groups in either crude or propensity score-matched analysis (DES 14.1% vs. DCB 14.7%, P = 0.864, DES 12.1% vs. 12.1%, P = 1.00). Target lesion thrombosis was not observed in the DCB group; however, stent thrombosis was observed in 7 patients (2.2%) in the DES group. The rate of binary restenosis was similar in both groups (DES, 20.9% vs. DCB, 22.8%; P = 0.749). The late lumen loss at follow-up was significantly greater in the DES group than in the DCB group (0.61 ± 0.76 mm vs 0.22 ± 0.48 mm; P < 0.001). Late lumen enlargement was observed in 38.6% of patients in the DCB group. CONCLUSION: The efficacy of DCB angioplasty for de novo coronary artery lesions in dialysis patients was similar to that of DES angioplasty in the real world. Drug-coated balloon angioplasty can be an acceptable treatment for de novo coronary artery lesions in dialysis patients.

Screening of primary aldosteronism by clinical features and daily laboratory tests: combination of urine pH, sex, and serum K.

OBJECTIVE: To develop and validate a scoring system for selection of patients who should proceed to endocrinologic examinations of primary aldosteronism in newly diagnosed hypertensive patients. METHODS: A multivariate logistic regression analysis for primary aldosteronism was undertaken by use of seven possible primary aldosteronism markers, age less than 40 years, female sex, moderate-to-severe hypertension, hypokalemia, serum Na minus Cl at least 40 mmol/l, serum uric acid 237.92 µmol/l or less (4.0 mg/dl), and urine pH (U-pH) at least 7.0, in consecutive outpatients newly diagnosed with hypertension. The diagnostic criteria of primary aldosteronism were plasma aldosterone concentration-to-plasma renin activity ratio [ARR, (ng/dl)/(ng/ml per h)] at least 20 and at least one positive result in four types of challenge tests. RESULTS: Of 130 patients, 24 were diagnosed with primary aldosteronism. The area under the receiver operating characteristic curve (AUC) for a logistic model incorporating all possible primary aldosteronism markers was 0.73 [95% confidence interval (CI): 0.61-0.85]. Removing high U-pH, female sex, and hypokalemia from the full model decreased the AUC by 0.059, 0.035, and 0.011, respectively. We devised pH of urine, female sex, low serum K (PFK) score, in which one point each was assigned to high U-pH, female sex, and hypokalemia. The prevalences of primary aldosteronism in patients with 0, 1, 2, and 3 points were 11, 14, 42, and 60%, respectively. In external validation datasets (n = 106), AUC of PFK score was significantly higher than that of hypokalemia alone (0.73, 95% CI: 0.63-0.83 vs. 0.53, 95% CI: 0.44-0.63, P < 0.01). CONCLUSION: PFK score may be a better parameter than hypokalemia alone for identifying patients with a high probability of having primary aldosteronism.

Suppression of autophagic flux contributes to cardiomyocyte death by activation of necroptotic pathways.

BACKGROUND: The role of necroptosis in myocardial injury has not been fully characterized. Here we examined roles of mitochondrial permeability transition pore (mPTP) and autophagy in necroptosis of cardiomyocytes. METHODS AND RESULTS: In H9c2 cells, necroptosis was induced by treatment with TNF-α (TNF) and z-VAD-fmk (zVAD) for 24h, and necroptotic death was determined by LDH release (as % of total). TNF/zVAD increased LDH release from 16.6±4.3% to 60.6±2.7%, and the LDH release was suppressed by necrostatin-1 (29.4±4.0%), a RIP1 inhibitor, and by siRNA-mediated knockdown of RIP3 (27.7±2.0%), confirming RIP1-RIP3-dependent necroptosis. TNF/zVAD-induced necroptosis was not attenuated by mPTP inhibitors or GSK-3ß inhibitors. TNF/zVAD increased LC3-II level, but the change was not further enhanced by bafilomycin A1. The increase of LC3-II by TNF/zVAD was associated with suppression of both autophagic flux and LC3-LAMP1 co-localization. TNF/zVAD did not modify phosphorylation of Akt, p70s6K, AMPK, ULK1 or VASP but significantly increased RIP1-p62 binding and conversely reduced p62-LC3 binding. Rapamycin inhibited RIP1-p62 and RIP1-RIP3 interactions induced by TNF/zVAD and partly restored autophagic flux and suppressed LDH release in TNF/zVAD-treated cells. The effect of rapamycin on LDH release was reduced by knockdown of Atg5 expression. Knockdown of p62 by siRNA augmented LDH release by TNF/zVAD. CONCLUSION: Suppression of autophagic flux contributes to RIP1-RIP3 interaction and necroptosis of cardiomyocytes, and sequestration of p62 from its interaction with LC3-II by p62-RIP1 interaction possibly underlies the suppressed autophagy. The mPTP is unlikely to play a major role in execution of necroptosis in cardiomyocytes.

Insufficient activation of Akt upon reperfusion because of its novel modification by reduced PP2A-B55α contributes to enlargement of infarct size by chronic kidney disease.

Chronic kidney disease (CKD) increases myocardial infarct size by an unknown mechanism. Here we examined the hypothesis that impairment of protective PI3K-PDK1-Akt and/or mTORC-Akt signaling upon reperfusion contributes to CKD-induced enlargement of infarct size. CKD was induced in rats by 5/6 nephrectomy (SNx group) 4 weeks before myocardial infarction experiments, and sham-operated rats served as controls (Sham group). Infarct size as a percentage of area at risk after ischemia/reperfusion was significantly larger in the SNx group than in the Sham group (56.3 ± 4.6 vs. 41.4 ± 2.0%). In SNx group, myocardial p-Akt-Thr308 level at baseline was elevated, and reperfusion-induced phosphorylation of p-Akt-Ser473, p-p70s6K and p-GSK-3ß was significantly suppressed. Inhibition of Akt-Ser473 phosphorylation upon reperfusion by Ku-0063794 significantly increased infarct size in the Sham group but not in the SNx group. There was no difference between the two groups in activities of mTORC2 and PDK1 and protein level of PTEN. However, the PP2A regulatory subunit B55α, which specifically targets Akt-Thr308, was reduced by 24% in the SNx group. Knockdown of B55α by siRNA increased baseline p-Akt-Thr308 and blunted Akt-Ser473 phosphorylation in response to insulin-like growth factor-1 (IGF-1) in H9c2 cells. A blunted response of Akt-Ser473 to IGF-1 was also observed in HEK293 cells transfected with a p-Thr308-mimetic Akt mutant (T308D). These results indicate that increased Akt-Thr308 phosphorylation by down-regulation of B55α inhibits Akt-Ser473 phosphorylation upon reperfusion in CKD and that the impaired Akt activation by insufficient Ser473 phosphorylation upon reperfusion contributes to infarct size enlargement by CKD.

A Case of Crescentic Glomerulonephritis Complicated with Hypocomplementemic Urticarial Vasculitis Syndrome and ANCA-Associated Vasculitis.

Systemic urticaria in a 64-year-old woman was diagnosed as leukocytoclastic vasculitis by a punch biopsy of the skin. Her physical findings improved after prescription of prednisolone at a dose of 20 mg/day, but the skin rash relapsed with renal dysfunction, proteinuria, and hematuria when the dose of prednisolone was reduced over a period of 9 months to 1 mg/day. She was admitted to our institute for further examination, when urinary protein and plasma creatinine levels were 0.8 g/day and 1.7 mg/dL, respectively. Complement analysis showed that levels of total hemolytic component, component C3 fraction, and component C4 fraction were 30∼60% of normal values and the titer of anti-neutrophil cytoplasmic antibody for myeloperoxidase (MPO-ANCA) was 89 EU (normal range, <10 EU), though there were no immunologic disorders such as systemic lupus erythematosus. Cellular crescentic glomerulonephritis was observed by light microscopy, and immunofluorescent studies showed positive staining for IgG, IgM, C3, C4, and C1q. Electron microscopy showed mesangial and subendothelial deposits with circumferential mesangial interposition. She fulfilled the diagnostic criteria for hypocomplementemic urticarial vasculitis syndrome (HUV), and ANCA-associated vasculitis (AAV) was also indicated by small vessel vasculitis and positive MPO-ANCA. Steroid pulse therapy with methylprednisolone followed by oral prednisolone improved her general condition and hypocomplementemia, and MPO-ANCA became negative. HUV and AAV are distinct clinical disorders, though both affect small blood vessels. Here we report a case of AAV-complicated HUV with crescentic glomerulonephritis.

Chronic Treatment With an Erythropoietin Receptor Ligand Prevents Chronic Kidney Disease-Induced Enlargement of Myocardial Infarct Size.

Chronic kidney disease (CKD) is known to increase myocardial infarct size after ischemia/reperfusion. However, a strategy to prevent the CKD-induced myocardial susceptibility to ischemia/reperfusion injury has not been developed. Here, we examined whether epoetin ß pegol, a continuous erythropoietin receptor activator (CERA), normalizes myocardial susceptibility to ischemia/reperfusion injury by its effects on protective signaling and metabolomes in CKD. CKD was induced by 5/6 nephrectomy in rats (subtotal nephrectomy, SNx), whereas sham-operated rats served controls (Sham). Infarct size as percentage of area at risk after 20-minutes coronary occlusion/2-hour reperfusion was larger in SNx than in Sham: 60.0±4.0% versus 43.9±2.2%. Administration of CERA (0.6 µg/kg SC every 7 days) for 4 weeks reduced infarct size in SNx (infarct size as percentage of area at risk=36.9±3.9%), although a protective effect was not detected for the acute injection of CERA. Immunoblot analyses revealed that myocardial phospho-Akt-Ser473 levels under baseline conditions and on reperfusion were lower in SNx than in Sham, and CERA restored the Akt phosphorylation on reperfusion. Metabolomic analyses showed that glucose 6-phosphate and glucose 1-phosphate were reduced and malate:aspartate ratio was 1.6-fold higher in SNx than in Sham, suggesting disturbed flux of malate-aspartate shuttle by CKD. The CERA improved the malate:aspartate ratio in SNx to the control level. In H9c2 cells, mitochondrial Akt phosphorylation by insulin-like growth factor-1 was attenuated by malate-aspartate shuttle inhibition. In conclusion, the results suggest that a CERA prevents CKD-induced susceptibility of the myocardium to ischemia/reperfusion injury by restoration of Akt-mediated signaling possibly via normalized malate-aspartate shuttle flux.

Inhibition of DPP-4 reduces acute mortality after myocardial infarction with restoration of autophagic response in type 2 diabetic rats.

BACKGROUND: Type 2 diabetes mellitus (T2DM) worsens the outcome after myocardial infarction (MI). Here, we hypothesized that inhibition of dipeptidyl peptidase-4 (DPP-4) improves survival after MI in T2DM by modifying autophagy in the non-infarcted region of the heart. METHODS AND RESULTS: Under baseline conditions, there was no significant difference between levels of myocardial autophagy marker proteins in OLETF, a rat model of T2DM, and in LETO, a non-diabetic control. However, in contrast to the response in LETO, LC3-II protein and LC3-positive autophagosomes in the non-infarcted region of the myocardium were not increased after MI in OLETF. The altered autophagic response in OLETF was associated with lack of AMPK/ULK-1 activation, attenuated response of Akt/mTOR/S6 signaling and increased Beclin-1-Bcl-2 interaction after MI. Treatment with vildagliptin (10 mg/kg/day s.c.), a DPP-4 inhibitor, suppressed Beclin-1-Bcl-2 interaction and increased both LC3-II protein level and autophagosomes in the non-infarcted region in OLETF, though it did not normalize AMPK/ULK-1 or mTOR/S6 signaling. Plasma insulin level, but not glucose level, was significantly reduced by vildagliptin at the dose used in this study. Survival rate at 48 h after MI was significantly lower in OLETF than in LETO (32 vs. 82%), despite similar infarct sizes. Vildagliptin improved the survival rate in OLETF to 80%, the benefit of which was abrogated by chloroquine, an autophagy inhibitor. CONCLUSIONS: The results indicate that vildagliptin reduces T2DM-induced increase in post-MI acute mortality possibly by restoring the autophagic response through attenuation of Bcl-2-Beclin-1 interaction.

Excessive degradation of adenine nucleotides by up-regulated AMP deaminase underlies afterload-induced diastolic dysfunction in the type 2 diabetic heart.

Type 2 diabetes mellitus (T2DM) is often complicated with diastolic heart failure, which decompensates under increased afterload. Focusing on cardiac metabolomes, we examined mechanisms by which T2DM augments ventricular diastolic stiffness in response to pressure overloading. Pressure-volume relationships (PVRs) and myocardial metabolomes were determined at baseline and during elevation of aortic pressure by phenylephrine infusion in a model of T2DM, OLETF, and its non-diabetic control, LETO. Pressure overloading augmented diastolic stiffness without change in systolic reserve in OLETF as indicated by a left-upward shift of end-diastolic PVR. In contrast, PVRs under cardioplegic arrest in buffer-perfused isolated hearts were similar in OLETF and LETO, indicating that extracellular matrix or titin remodeling does not contribute to the afterload-induced increase in stiffness of the beating ventricle of OLETF. Metabolome analyses revealed impaired glycolysis and facilitation of the pentose phosphate pathway in OLETF. Pressure overloading significantly reduced ATP and total adenine nucleotides by 34% and 40%, respectively, in OLETF but not in LETO, while NADH-to-NAD(+) ratios were similar in the two groups. The decline in ATP by pressure overloading in OLETF was associated with increased inosine 5-monophosphate and decreased adenosine levels, being consistent with the 2.5-times higher activity of cardiac AMP deaminase in OLETF. Tissue ATP level was negatively correlated with tau of LV pressure and LVEDP. These results suggest that ATP depletion due to excessive degradation of adenine nucleotides by up-regulated AMP deaminase underlies ventricular stiffening during acute pressure overloading in T2DM hearts.

Translocation of glycogen synthase kinase-3ß (GSK-3ß), a trigger of permeability transition, is kinase activity-dependent and mediated by interaction with voltage-dependent anion channel 2 (VDAC2).

Glycogen synthase kinase-3ß (GSK-3ß) is a major positive regulator of the mitochondrial permeability transition pore (mPTP), a principle trigger of cell death, under the condition of oxidative stress. However, the mechanism by which cytosolic GSK-3ß translocates to mitochondria, promoting mPTP opening, remains unclear. Here we addressed this issue by analyses of the effect of site-directed mutations in GSK-3ß on mitochondrial translocation and protein/protein interactions upon oxidative stress. H9c2 cardiomyoblasts were transfected with GFP-tagged GSK-3ß (WT), a mutant GSK-3ß insensitive to inhibitory phosphorylation (S9A), or kinase-deficient GSK-3ß (K85R). Time lapse observation revealed that WT and S9A translocated from the cytosol to the mitochondria more promptly than did K85R after exposure to oxidative stress. H2O2 increased the density of nine spots on two-dimensional gel electrophoresis of anti-GSK-3ß-immunoprecipitates by more than 3-fold. MALDI-TOF/MS analysis revealed that one of the spots contained voltage-dependent anion channel 2 (VDAC2). Knockdown of VDAC2, but not VDAC1 or VDAC3, by siRNA attenuated both the mitochondrial translocation of GSK-3ß and mPTP opening under stress conditions. The mitochondrial translocation of GSK-3ß was attenuated also when Lys-15, but not Arg-4 or Arg-6, in the N-terminal domain of GSK-3ß was replaced with alanine. The oxidative stress-induced mitochondrial translocation of GSK-3ß was associated with an increase in cell death, which was suppressed by lithium chloride (LiCl), a GSK-3ß inhibitor. These results demonstrate that GSK-3ß translocates from the cytosol to mitochondria in a kinase activity- and VDAC2-dependent manner in which an N-terminal domain of GSK-3ß may function as a mitochondrial targeting sequence.

Does glycemic control reverse dispersion of ventricular repolarization in type 2 diabetes?

BACKGROUND: Abnormal ventricular repolarization is a predictor of cardiovascular mortality. In this study, we tested the hypothesis that glycemic control reverses abnormal ventricular repolarization in patients with type 2 diabetes. METHODS: We analyzed longitudinal changes in repolarization indices of electrocardiograms in retrospectively enrolled 44 patients with type 2 diabetes and 44 age-matched healthy subjects. RESULTS: In the diabetic group, BMI was greater, levels of HbA1c (10.0 ± 1.6 vs. 5.6 ± 0.3%) and triglyceride were higher and level of HDL cholesterol was lower than those in the control group. Although mean QTc intervals were similar (413.6 ± 18.5 vs. 408.3 ± 22.7 ms), QT dispersion (41.8 ± 15.4 vs. 28.7 ± 7.7 ms) and Tpeak-Tend in lead V5 (83.6 ± 13.6 vs. 71.3 ± 10.3 ms) were significantly longer in the diabetic group than in the control group, indicating increased heterogeneity of ventricular repolarization in type 2 diabetes. During follow-up of 36 patients in the diabetic group for 787 ± 301 days, HbA1c level decreased to 7.3 ± 1.6%, while BMI did not significantly change. In contrast to HbA1c, QT dispersion (45.8 ± 15.0 ms) and Tpeak-Tend in lead V5 (83.6 ± 10.6 ms) were not significantly reduced during the follow-up period. There was no correlation between the change in HbA1c and the change in QT dispersion or Tpeak-Tend. CONCLUSIONS: Increased heterogeneity of ventricular repolarization in type 2 diabetic patients was not reduced during the relatively short follow-up period despite significantly improved glycemic control.

The impact of elevation of serum uric acid level on the natural history of glomerular filtration rate (GFR) and its sex difference.

BACKGROUND: The impact of elevation of the serum uric acid level (SUA) on the natural history of glomerular filtration rate (GFR) remains controversial. METHODS: If elevation of SUA is a result, rather than a cause, of a decline in GFR, the relationship between SUA and GFR should be the same in the same population over years except for shifts by age-dependent reduction of GFR. We tested this hypothesis using data from two cohorts and a group of allopurinol-treated patients. RESULTS: In Cohort 1 consisting of urban residents aged 40.6 ± 9.0 years (n = 3 446), SUA was inversely correlated with estimated GFR (eGFR) in both men and women, and the slope of the SUA-eGFR relationship was steeper in women than in men. The slopes of the regression lines became significantly steeper after a 6-year interval in both sexes, and the change in the slope was larger in women. A similar sex difference in the SUA-eGFR relationship and 6-year change in the slope were observed in Cohort 2 consisting of rural town residents aged 61.7 ± 12.2 years (n = 404). Multiple regression analyses showed that explanatory factors of eGFR after a 6-year interval were age and SUA at baseline in both cohorts, and partial regression coefficients of SUA were more negative in women than in men. The SUA-eGFR relationship in allopurinol-treated patients (n = 346, 63.5 ± 13.3 years old) was similar to that in Cohort 2. CONCLUSIONS: The results indicate that elevation of SUA accelerates the yearly decline in eGFR and that women are more susceptible to urate-induced decline in eGFR.