Hypoxia-inducible factor-prolyl hydroxylase inhibitor Roxadustat (FG-4592) reduces renal fibrosis in Dahl salt-sensitive rats.

OBJECTIVE: Although hypoxia-inducible factor-prolyl hydroxylase (HIF-PH) inhibitors have been developed for the treatment of renal anemia, their effects on cardiac and renal dysfunction remain unknown. We previously reported on Dahl salt-sensitive rats, in a rat model of salt-sensitive hypertension, that exhibited anemia and impaired expression of duodenal iron transporters after the development of hypertensive cardiac and renal dysfunction. Therefore, we investigated the effects of Roxadustat (FG-4592), an HIF-PH inhibitor, on anemia, iron regulation, and cardiac and renal dysfunction in Dahl salt-sensitive rats. METHODS: Six-week-old male Dahl salt-sensitive rats were fed a normal or high-salt diet for 8 weeks. A further subset of Dahl salt-sensitive rats, that were fed a high-salt diet, was administered Roxadustat for 8 weeks. RESULTS: Dahl salt-sensitive rats fed a high-salt diet developed hypertension, cardiac and renal dysfunction, and anemia after 8 weeks of feeding. Roxadustat increased hemoglobin and serum erythropoietin levels in Dahl salt-sensitive rats fed a high-salt diet. With regard to the iron-regulating system, Roxadustat lowered hepatic hepcidin gene expression and increased the gene expression of duodenal iron transporters, such as cytochrome b and divalent metal transporter 1 , in Dahl salt-sensitive rats fed a high-salt diet. Roxadustat did not affect the development of hypertension and cardiac hypertrophy in Dahl salt-sensitive rats with a high-salt diet; however, Roxadustat treatment attenuated renal fibrosis in these rats. CONCLUSIONS: Roxadustat ameliorated anemia with affecting the gene expression of the iron-regulating system, and did not affect cardiac hypertrophy but attenuated renal fibrosis in Dahl salt-sensitive rats fed a high-salt diet.

Plasma renin activity variation following admission predicts patient outcome in acute decompensated heart failure with reduced and mildly reduced ejection fraction.

Plasma renin activity (PRA) level at admission is reported to be a prognostic predictor of acute decompensated heart failure (ADHF) patients. Although PRA is affected during hospitalization by several factors including fluid volume and drug titration, whether the changes in PRA levels during hospitalization (ΔPRA) are associated with prognosis of ADHF patients are largely unknown. PURPOSE: Investigate the predictive impact of ΔPRA on the prognosis of ADHF patients with reduced ejection fraction (HFrEF) and mildly reduced ejection fraction (HFmrEF). METHODS: Retrospectively analyzed consecutive 116 HFrEF and HFmrEF patients admitted for ADHF. PRA measurements were acquired at admission and at discharge. The primary outcome was a composite of cardiovascular death and HF re-hospitalization. RESULTS: Out of 116 patients, 85 had PRA measurements both at admission and at discharge. Compared to admission, PRA level was significantly higher at discharge (0.8 (IQR 0.3-2.2) to 2.8 (IQR 1.0-7.2), p < 0.001). Tertiary groups ranked by PRA level on admission showed trend of poor prognosis in order of high, mid, and low PRA level (p = 0.07). On the contrary, PRA level at discharge significantly differentiated the prognosis and was poor in order of high, low, and mid (p = 0.026). Next, when the participants were divided into tertiary groups ranked by ΔPRA, prognosis worsened in the order of "minimal", "decreasing", and the "increasing" tier. Cubic splines analysis also indicate a similar tendency. CONCLUSIONS: In ADHF patients with HFrEF and HFmrEF, patients with minimal ΔPRA showed the better prognosis over the those with either increasing or decreasing.

I536T variant of RBM20 affects splicing of cardiac structural proteins that are causative for developing dilated cardiomyopathy.

RBM20 is one of the genes predisposing to dilated cardiomyopathy (DCM). Variants in the RS domain have been reported in many DCM patients, but the pathogenicity of variants within the RNA-recognition motif remains unknown. Two human patients with the I536T-RBM20 variant without an apparent DCM phenotype were identified in sudden death cohorts. A splicing reporter assay was performed, and an I538T knock-in mouse model (Rbm20I538T) was generated to determine the significance of this variant. The reporter assay demonstrated that the human I536T variant affected the TTN splicing pattern compared to wild-type. In the mouse experiments, Rbm20I538T mice showed different splicing patterns in Ttn, Ldb3, Camk2d, and Ryr2. The expressions of Casq1, Mybpc2, and Myot were upregulated in Rbm20I538T mice, but Rbm20I538T mice showed neither DCM nor cardiac dysfunction on histopathological examination and ultrasound echocardiography. The I536T-RBM20 (I538T-Rbm20) variant changes gene splicing and affects gene expression, but the splicing and expression changes in Ttn and Ca handling genes such as Casq1, Camk2d, and Ryr2 do not cause DCM morphology in the mouse model. KEY MESSAGES: • Two human patients with the I536T-RBM20 variant without a DCM phenotype were identified. • A splicing reporter assay demonstrated that the variant affected the TTN splicing. • Rbm20I538T mice showed neither DCM nor cardiac dysfunction. • Rbm20I538T mice showed different splicing patterns and the gene expressions.

Clinical utility of reticulocyte hemoglobin equivalent in patients with heart failure.

Anemia and iron deficiency (ID) are common in patients with heart failure (HF) and intravenous (IV) administration of iron to patients hospitalized for decompensated HF with ID improves outcome. The diagnosis of ID in routine practice is based on serum ferritin and transferrin saturation (TSAT) but both have limitations; alternatives should be considered. Reticulocyte hemoglobin equivalent (Ret-He) reflects iron content in reticulocytes but its clinical utility in patients with HF remains uncertain. We prospectively enrolled 142 patients hospitalized for decompensated HF. Sixty five percent had ID as defined in current international guidelines. Ret-He was directly correlated with serum iron and ferritin concentrations and with TSAT. There was a poor relationship between quartile of Ret-He and HF hospitalization or death but increases or decreases in Ret-He between admission and discharge were associated with a worse outcome. The clinical utility of Ret-He for identifying ID and predicting response to IV iron and prognosis for patients with HF requires further investigation.

Urine albumin-to-creatinine ratio on admission predicts early rehospitalization in patients with acute decompensated heart failure.

Detecting high-risk patients for early rehospitalization is crucial in heart failure patient care. An association of albuminuria with cardiovascular events is well known. However, its predictive impact on rehospitalization for acute decompensated heart failure (ADHF) remains unknown. In this study, 190 consecutive patients admitted due to ADHF between 2017 and April 2019 who underwent urinalysis were enrolled. Among them, 140 patients from whom urine albumin-to-creatinine ratio (UACR) was measured with spot urine samples on admission were further analyzed. The association between UACR and rehospitalization due to HF during 1 year after discharge was evaluated. The mean age of 140 participants was 77.6 years and 55% were men. Only 18% (n = 25) of patients presented with normoalbuminuria (UACR < 30 mg/g∙creatinine), whereas 59% (n = 83) and 23% (n = 32) showed microalbuminuria (UACR 30-300 mg/g·creatinine) and macroalbuminuria (UACR > 300 mg/g·creatinine), respectively. The level of UACR on admission was correlated with the risk of subsequent rehospitalization due to HF (p = 0.017). The receiver operating characteristic analysis indicated that the best cut-off values for the UACR and B-type natriuretic peptide (BNP) levels to predict ADHF rehospitalization were 50 mg/g·creatinine and 824 pg/ml, respectively. When the patients were divided into four groups using both cut-off values, the individual predictive impacts of UACR and BNP on rehospitalization were comparable. Patients with both elevated UACR and BNP levels had a higher rate of HF rehospitalization than those with elevated BNP levels alone (p < 0.05). The combination of both values enabled more accurate prediction of HF rehospitalization than BNP levels alone. In conclusion, UACR could be a new useful biomarker to predict HF rehospitalization in patients with ADHF, especially in combination with the levels of BNP, and should be further evaluated in a prospective study.

Crosstalk between Iron and Arteriosclerosis.

Iron is an important element for life; however, intracellular labile iron overload can lead to the generation of reactive oxygen species and cellular damage. Although iron is mainly utilized for heme synthesis and is incorporated into hemoglobin, body iron status is often implicated in the pathogenesis of cardiovascular diseases. In a cell, iron is used for basic processes such as cell growth, maintenance, and repair. Thus, iron is considered to be involved in the pathogenesis of arteriosclerosis. In fact, clinical and experimental studies have shown an association between iron and arteriosclerosis. These data suggest the crosstalk between iron and arteriosclerosis. However, iron metabolism in arteriosclerosis is often complicated, and the systemic and cellular mechanisms of iron homeostasis in arteriosclerosis remain completely unsolved. Thus, in this review, we aimed to examine the role of iron in arteriosclerosis.

Anemia has an impact on prognosis in heart failure with preserved ejection fraction with mild chronic kidney disease.

BACKGROUND: Anemia and chronic kidney disease (CKD) are common in patients with heart failure with preserved left ventricular fraction (HFpEF). However, it is entirely unknown about the impact of anemia on prognosis in HFpEF patients with CKD. In this study, we investigated the impact of anemia on prognosis and the optimal hemoglobin (Hb) levels to predict prognosis in HFpEF patients with CKD. METHODS AND RESULTS: We prospectively examined 523 consecutive HFpEF patients enrolled in Japanese heart failure syndrome with preserved ejection fraction registry. CKD was defined as an estimated glomerular filtration rate (eGFR) of <60 mL /min/1.73 m2. The prevalence rate of anemia was 78% in HFpEF patients with CKD by using the World Health Organization criteria. Kaplan-Meier analysis for all-cause mortality and heart failure rehospitalization demonstrated that anemic patients had poor prognosis compared with non-anemic patients in HFpEF patients with CKD, but not those without CKD. According to the degree of CKD, anemia affected prognosis in HFpEF patients with mild CKD (45 ≤ eGFR < 60), but not those with moderate to severe CKD (15 ≤ eGFR < 45). Additionally, multivariate analysis revealed that anemia and Hb levels were independent predictors of composite outcomes in HFpEF patients with mild CKD, but not those with moderate to severe CKD. Finally, survival classification and regression tree analysis showed that the optimal Hb levels to predict composite outcomes were 10.7 g/dL in those with mild CKD. CONCLUSIONS: Anemia has an impact on prognosis in HFpEF patients, especially among those with mild CKD.

Iron and cardiovascular diseases.

Iron is a necessary element for life; however, excess iron leads to oxidative stress by the Fenton reaction. Iron deficiency is prevalent in patients with heart failure, while iron overload is associated in the pathogenesis of atherosclerosis. These findings suggest the "iron paradox" in cardiovascular diseases. Iron metabolism in cardiovascular diseases is complex, and the mechanisms regulating systemic and cellular iron metabolism in cardiovascular diseases remain completely unknown. In this review, we focus on the role of iron in cardiovascular diseases.

Reduced lifespan of erythrocytes in Dahl/Salt sensitive rats is the cause of the renal proximal tubule damage.

We studied the mechanisms of anemia and the influence of anemia on renal pathology in Dahl/Salt Sensitive (Dahl/SS) rat, a model of cardio-renal-anemia syndrome. Erythrocyte lifespan was shortened and associated with decreased hemoglobin level in the Dahl/SS rats given high-salt diet. Serum haptoglobin decreased, reticulocytes increased, and erythropoiesis in the bone marrow and extramedullary hematopoiesis in the spleen was markedly stimulated by increased serum erythropoietin in them. As a mechanism of hemolysis, we investigated the incidence of eryptosis, suicidal death of erythrocytes. Eryptosis was increased, and red blood cell-derived microparticles, small particle which are generated in hemolytic disease, were also increased in Dahl/SS rats fed with high-salt diet. Deposition of hemosiderin and mitochondrial morphologic abnormality, a sign of ferroptosis, in proximal renal tubules was associated with intravascular hemolysis. Treatment with deferasirox, an oral iron chelator, reduced the renal proximal tubular injury and the glomerular sclerosis in Dahl/SS rats fed with high-salt diet. In conclusion, reduced half-life of erythrocytes induced by hemolysis is the major cause of anemia in Dahl/SS rat. Iron accumulation induced by hemolysis causes renal proximal tubule injury and accelerates renal damage in this model.

Manipulation of beta-adrenergic receptor in pressure-overloaded murine hearts mimics adverse and reverse cardiac remodeling.

Transverse aortic constriction (TAC) has been widely used to create pressure overload induced heart failure in mice. However, this conventional model has some limitations such as low reproducibility and long creation period of cardiac failure. In order to establish a highly reproducible cardiac failure model that mimics adverse cardiac remodeling (ACR) we combined pressure overload and beta-adrenergic receptor stimuli using isoproterenol (ISO) and explored the optimal TAC model by changing the durations of TAC and the doses of ISO. Thus we constructed a suitable model for ACR with an effective combination of 3-week TAC and subsequent one-week ISO (3 mg/kg/day) infusion. Using RNA-Seq analyses, we identified that the up-regulated genes were mainly related to fibrosis including Fbn1, C1qtnf6 and Loxl2; and that the down-regulated genes were associated with mitochondrial function including Uqcrc1, Ndufs3, and Idh2 in failing hearts of our ACR model. Next, we followed the changes in cardiac function after ceasing ISO infusion. Left ventricular function gradually recovered after cessation of ISO, suggesting cardiac reverse remodeling (CRR). Gene expression signatures of hearts, which exhibited CRR, were almost identical to that of TAC hearts without ISO. In conclusion, our new model exhibits a transition to ACR and subsequent CRR with high reproducibility. This murine model might add new insights into the experiments of heart failure technically as well as scientifically.

Anomalous origin of the coronary artery coursing between the great vessels presenting with a cardiovascular event (J-CONOMALY Registry).

AIMS: Anomalous origin of the coronary artery (AOCA) with an inter-arterial course (IAC) between the great vessels poses a risk for a life-threatening cardiovascular event. We assessed, in a registry-based study, the clinical features, treatment strategies, and prognoses of life-threatening cardiovascular events ensuant to AOCA. METHODS AND RESULTS: Included were 65 AOCA patients (48 men/17 women, aged 41 ± 23 years) from 40 clinical centres who had experienced sudden cardiac arrest (SCA) (n = 30), acute myocardial infarction (AMI) (n = 5), angina (n = 23), or syncope (n = 7). The anomalous vessel was the right coronary artery in 72% of patients and left coronary artery in 28%; the ostium was slit-like in 42%. Coronary luminal narrowing ≥75% was absent in patients with SCA or syncope (86% and 57%, respectively), but occlusion or narrowing was seen in those with AMI (100%) or angina (52%). Age ≤40 years, male sex, sporting activity, absence of prodromal symptoms, acutely angled (≤30°) take-off from the aorta, and absence of luminal narrowing of the IAC segment were associated with SCA in this patient group. Coronary vasospasm was inducible in 12 of 17 patients without coronary narrowing. Management included surgical revascularization (n = 26) percutaneous coronary intervention (n = 9), and medical treatment (n = 26). Four SCA patients died while hospitalized; no others died during the median 5.0 (range, 1.8-7.0)-year follow-up period. CONCLUSIONS: In patients with AOCA, age ≤40 years, male sex, sporting activity, and an acute take-off angle appear to be risk factors for SCA. Appropriate management can be beneficial. Confirmation in a large-scale study is warranted.

Effects of Heterozygous TfR1 (Transferrin Receptor 1) Deletion in Pathogenesis of Renal Fibrosis in Mice.

Renal fibrosis is the final pathological process common for several types of end-stage renal diseases, including obstructive nephropathy and diabetic kidney disease. Substantial renal iron loads and oxidative stress have been reported to contribute to the development of renal diseases. TfR1 (transferrin receptor 1) plays a crucial role in cellular iron transport. However, there are no studies investigating TfR1 in the pathophysiology of renal fibrosis. Here, we investigate the role of TfR1 in the development of renal fibrosis. Primarily, to ascertain an association of TfR1 in the pathophysiology of renal fibrosis, we induced unilateral ureteral obstruction in wild-type (WT) and heterozygous TfR1 deleted (TfR1+/-) mice. TfR1+/- mice exhibited attenuated renal fibrosis, along with reduced renal expression of ferritin and 4-hydroxynonenal as compared with WT mice after unilateral ureteral obstruction. In addition, renal expression of TGFß-RI (transforming growth factor-ß receptor I) and Smad2, downstream signaling of TGFß-RI was attenuated in TfR1+/- mice compared with WT mice after unilateral ureteral obstruction. Next, we investigated the role of TfR1 in the development of diabetic kidney disease. No difference was observed in blood glucose levels and urinary albumin:creatinine ratios between WT and TfR1+/- diabetic mice after streptozotocin administration. In contrast, TfR1+/- mice showed suppressed renal fibrosis, along with reduced renal expression of ferritin, 4-hydroxynonenal, TGFß-RI, and Smad2 compared with WT mice after streptozotocin administration. These results suggest that TfR1 plays an important role in the development of renal fibrosis.

Reduction in Left Ventricular Ejection Fraction is Associated with Subsequent Cardiac Events in Outpatients with Chronic Heart Failure.

Left ventricular ejection fraction (LVEF) is critical for determining the prognosis and treatment of patients with heart failure (HF). However, the influence of serial LVEF changes in patients with stable chronic HF (CHF) has not yet been completely investigated. We analyzed data of 263 outpatients with CHF from the J-MELODIC study cohort and evaluated the frequency of cardiac events. We stratified patients into tertiles based on the relative difference in LVEF in 1 year and that at baseline. We found a significant difference in the cardiac event rate among the three groups (log-rank test, p = 0.042). We identified a relative 11% LVEF reduction as the optimal cutoff value based on the receiver operating characteristics analysis. LVEF (OR, 1.04; 95% CI, 1.01-1.07; p = 0.015) and E/e' (OR, 1.06; 95% CI, 1.01-1.12; p = 0.023) at baseline were predictors of >11% LVEF reduction. After adjusting the variables including age and sex, >11% LVEF reduction was an independent predictor of subsequent cardiac events (HR, 5.79; 95% CI, 2.49-13.2; p < 0.001). In conclusion, patients with 1-year relative >11% LVEF reduction may have subsequent worsening outcomes. Such patients should be carefully followed-up as high risk population for development of cardiac events.

Haploinsufficiency of Transferrin Receptor 1 Impairs Angiogenesis with Reduced Mitochondrial Complex I in Mice with Limb Ischemia.

Limb ischemia (LI) is a major consequence of peripheral artery disease (PAD) with a high mortality rate. Iron is an essential mineral to maintain physiological function of multiple organs. Intracellular iron transport is regulated by transferrin receptor 1 (TfR1). Although increase in serum ferritin levels has been reported in PAD patients, the mechanism of iron metabolism in LI is still unclear. The aim of this study is to investigate whether TfR1 deletion attenuates LI formation. To generate LI, the left femoral artery of 8-10 week-old C57BL6/J male mice was ligated. Adductor muscles were harvested at 28 days after surgery to investigate iron metabolism. The level of ferritin, intracellular iron storage protein, was higher in ischemic adductor muscles compared to non-ischemic adductor muscles. Level of intracellular iron transport protein, TfR1, was decreased in ischemic adductor muscles. LI was then generated in TfR1 heterozygous deleted mice (TfR1+/-) to examine whether TfR1 contributes to the pathophysiology of LI. Laser Doppler blood flowmetry revealed that blood flow recovery was attenuated in TfR1+/- mice compared to wild type (WT) littermates, along with decreased expression of ferritin and CD31 in ischemic adductor muscles. Since iron is used for energy production in mitochondria, we then assessed mitochondrial complexes in the ischemic adductor muscle. Of interest, expression of mitochondrial complex I, but not complexes II, III, and V in ischemic adductor muscles was significantly reduced in TfR1+/- mice compared to WT mice. Haploinsufficiency of TfR1 attenuated angiogenesis via reduction of mitochondrial complex I in LI in mice.

Effective blood hemoglobin level to predict prognosis in heart failure with preserved left ventricular ejection fraction: results of the Japanese heart failure syndrome with preserved ejection fraction registry.

High prevalence of anemia in heart failure with preserved left ventricular ejection fraction (HFpEF) has been reported. However, little is known about the association of anemia and gender with prognosis in HFpEF patients. In addition, effective blood hemoglobin (Hb) level for prognosis in HFpEF patients remains largely unknown. In this study, we investigated the association between anemia, gender, and prognosis in 535 HFpEF patients enrolled in Japanese heart failure syndrome with preserved ejection fraction registry. Furthermore, we assessed effective blood Hb level to predict prognosis in HFpEF patients. According to the World Health Organization criteria, the prevalence rate of anemia on admission was about 70% in both male and female HFpEF patients. Kaplan-Meier analysis for all-cause mortality demonstrated that anemic patients had poor prognosis compared with non-anemic patients in both male and female HFpEF patients. Interestingly, multivariate analysis revealed that blood Hb level at discharge was an independent predictor of all-cause mortality in both male and female HFpEF patients. According to survival classification and regression tree analysis, blood Hb level at discharge of 9.4 g/dL for male and 12.3 g/dL for female was more accurate cutoff value to predict all-cause mortality in HFpEF patients. Anemia was implicated in poor prognosis in both male and female HFpEF patients. In particular, blood Hb level at discharge was an independent predictor of all-cause mortality in both male and female HFpEF patients. Effective cutoff value of blood Hb level at discharge to predict all-cause mortality was lower in male than in female HFpEF patients.

Impact of low tissue backscattering by optical coherence tomography on endothelial function after drug-eluting stent implantation.

This study evaluated the impact of optical coherence tomography (OCT)-derived low-backscattered tissue on mid-term coronary endothelial function after drug-eluting stent (DES) implantation. Although OCT enables detailed in vivo evaluation of neointimal tissue characterization after DES implantation, its association with physiological vascular healing response is unclear. Thirty-three stable angina pectoris patients underwent OCT examination and endothelial function testing with intracoronary infusion of incremental doses of acetylcholine 8-month after DES implantation in a single lesion of the left anterior descending artery. Neointimal tissue was classified into two patterns based on the predominant OCT light backscatter: high backscatter and low backscatter. Although the presence of uncovered or malapposed stent strut was not associated with the degree of vasoconstriction, the degree of vasoconstriction was significantly greater in the DES with low-backscattered neointima than in the DES without low-backscattered neointima (- 32.1 ± 25.7 vs. - 4.1 ± 20.1%, p = 0.003). Moreover, there was an inverse linear relationship between low backscatter tissue index and degree of vasoconstriction after acetylcholine infusion (r = 0.50 and p = 0.003). The endothelium-dependent vasomotor response after 8-month of DES was impaired in patients with low neointimal tissue backscatter on OCT imaging. OCT assessment of low-backscattered tissue may be used as surrogate markers for impairment of endothelial function after DES.

Effects of Weight Loss in Outpatients With Mild Chronic Heart Failure: Findings From the J-MELODIC Study.

BACKGROUND: Weight loss is a strong prognostic factor in chronic heart failure (CHF); however, little is known about its effects in patients with mild CHF. Therefore, we investigated the effects of weight loss in patients with mild CHF. METHODS AND RESULTS: We analyzed a total of 242 outpatients with mild CHF from the J-MELODIC study cohort. Weight loss was defined as ≥5% weight loss in 1 year. Twenty-seven patients (11.2%) lost ≥5% weight in 1 year. Weight loss was associated with higher rates of underweight and worsening renal function in 1 year compared with the absence of ≥5% weight loss. The predictors of weight loss included edema, B-type natriuretic peptide, and diabetes mellitus at baseline. Although weight loss was significantly associated with subsequent cardiovascular death or hospitalization for HF (log-rank P = .002) and subsequent death from any cause (log-rank P = .002), underweight was not associated with these outcomes (log-rank P = .356 and P = .168, respectively). Even after adjusting for covariates, weight loss was a significant and independent risk factor for subsequent cardiovascular death or hospitalization for HF (hazard ratio 3.22, 95% confidence interval 1.10-8.41; P = .034). CONCLUSIONS: In patients with mild CHF, ≥5% weight loss was a significant predictor for subsequent cardiovascular death or hospitalization for HF.