Although cardiac fibrosis causes heart failure, its molecular mechanisms remain elusive. In this study, we investigated the mechanisms of cardiac fibrosis and examined the effects of the antifibrotic drug pirfenidone (PFD) on chronic heart failure. To understand the responsible mechanisms, we generated an in vivo pressure-overloaded heart failure model via transverse aortic constriction (TAC) and examined the effects of PFD on chronic-phase cardiac fibrosis and function. In the vehicle group, contractile dysfunction and left ventricle fibrosis progressed further from 4 to 8 wk after TAC but were prevented by PFD treatment beginning 4 wk after TAC. We isolated cardiac fibroblasts and vascular endothelial cells from the left ventricles of adult male mice and investigated the cell-type-specific effects of PFD. Transforming growth factor-β induced upregulated collagen 1 expression via p38 phosphorylation and downregulated claudin 5 (Cldn5) expression in cardiac fibroblasts and endothelial cells, respectively; both processes were inhibited by PFD. Moreover, PFD inhibited changes in the collagen 1 and Cldn5 expression levels, resulting in reduced fibrosis and serum albumin leakage into the interstitial space during the chronic phase in TAC hearts. In conclusion, PFD inhibited cardiac fibrosis by suppressing both collagen expression and the increased vascular permeability induced by pressure overload.

Although high-throughput sequencing can elucidate the genetic basis of hereditary cardiomyopathy, direct interventions targeting pathological mutations have not been established. Furthermore, it remains uncertain whether homology-directed repair (HDR) is effective in non-dividing cardiomyocytes. Here, we demonstrate that HDR-mediated genome editing using CRISPR/Cas9 is effective in non-dividing cardiomyocytes. Transduction of adeno-associated virus (AAV) containing sgRNA and repair template into cardiomyocytes constitutively expressing Cas9 efficiently introduced a fluorescent protein to the C-terminus of Myl2. Imaging-based sequential evaluation of endogenously tagged protein revealed that HDR occurs in cardiomyocytes, independently of DNA synthesis. We sought to repair a pathological mutation in Tnnt2 in cardiomyocytes of cardiomyopathy model mice. An sgRNA that avoided the mutated exon minimized deleterious effects on Tnnt2 expression, and AAV-mediated HDR achieved precise genome correction at a frequency of ~12.5%. Thus, targeted genome replacement via HDR is effective in non-dividing cardiomyocytes, and represents a potential therapeutic tool for targeting intractable cardiomyopathy.

A 55-year-old man was admitted to our hospital for further examination of the abnormalities of chest X-ray and electrocardiogram. He was diagnosed with type B Wolff-Parkinson-White syndrome concomitant with dilated cardiomyopathy. Despite the medical therapy using enalapril and carvedilol for 20 months, his cardiac performance and brain natriuretic peptide (BNP) were not so improved. Because asynchronous septal motion caused by pre-excitation through a right-sided accessory pathway (AP) might deteriorate his cardiac performance, catheter ablation to the AP was performed. Successful procedure after 17 months improved left ventricular (LV) contraction, reduced LV volume, and decreased mitral regurgitation and BNP.

Aims Considerable variation in the relationships between the indices of left atrial (LA) volume and pressure could possibly affect the selection of medications or efforts to improve the prognoses of patients with heart failure and preserved ejection fraction (HFpEF). We aimed to clarify the association between the prognostic endpoint and LA overload indices in elderly patients with HFpEF. Methods and resultsWe analysed 898 patients with HFpEF hospitalized for acute decompensated heart failure (men/ women: 406/492). Blood tests and transthoracic echocardiography were performed before discharge. The primary endpoint was re-admission for heart failure or all-cause mortality. Stroke volume (SV)/left atrial volume (LAV), an index for LA volume overload, was a significant prognostic factor of re-admission for heart failure in the multivariable Cox hazard analysis adjusted for comorbidities [hazard ratio (HR) 0.616, 95% confidence interval (CI) 0.430-0.882, P = 0.008]. Additionally, the ratio of diastolic elastance (Ed) to arterial elastance (Ea), an index for LA pressure overload, was also significant (HR 1.444, 95% CI 1.014-2.058, P = 0.041). Furthermore, Ed/Ea, but not SV/LAV, was a significant prognostic factor of all-cause mortality (HR 1.594, 95% CI 1.102-2.306, P = 0.013). Conclusions The index of LA overload for prognosis may differ according to the different endpoints in elderly patients with HFpEF.

SummaryCardiac fibrosis is a pathological feature of myocardium of failing heart and plays causative roles in arrhythmia and cardiac dysfunction, but its regulatory mechanisms remain largely elusive. In this study, we investigated the effects of the novel EP4 receptor agonist ONO-0260164 on cardiac fibrosis in hypertrophied heart and explored the regulatory mechanisms in cardiac fibroblasts.In a mouse model of cardiac hypertrophy generated by transverse aortic constriction (TAC), ONO-0260164 treatment significantly prevented systolic dysfunction and progression of myocardial fibrosis at 5 weeks after TAC. In cultured neonatal rat cardiac fibroblasts, transforming growth factor-β1 (TGF-β1) induced upregulation of collagen type 1, alpha 1 (Col1a1) and type 3, alpha 1 (Col3a1), which was inhibited by ONO-0260164 treatment. ONO-0260164 activated protein kinase A (PKA) in the presence of TGF-β1 in the cardiac fibroblasts. PKA activation suppressed an increase in collagen expression induced by TGF-β1, indicating the important inhibitory roles of PKA activation in TGF-β1-mediated collagen induction.We have demonstrated for the first time the antifibrotic effects of the novel EP4 agonist ONO-0260164 in vivo and in vitro, and the important role of PKA activation in the effects. (Int Heart J 2017; 58: 107-114)

Post-mitotic cardiomyocytes have been considered to be non-permissive to precise targeted integration including homology-directed repair (HDR) after CRISPR/Cas9 genome editing. Here, we demonstrate that direct delivery of large amounts of transgene encoding guide RNA (gRNA) and repair template DNA via intra-ventricular injection of adeno-associated virus (AAV) promotes precise targeted genome replacement in adult murine cardiomyocytes expressing Cas9. Neither systemic injection of AAV nor direct injection of adenovirus promotes targeted integration, suggesting that high copy numbers of single-stranded transgenes are required in cardiomyocytes. Notably, AAV-mediated targeted integration in cardiomyocytes both in vitro and in vivo depends on the Fanconi anemia pathway, a key component of the single-strand template repair mechanism. In human cardiomyocytes differentiated from induced pluripotent stem cells, AAV-mediated targeted integration fluorescently labeled Mlc2v protein after differentiation, independently of DNA synthesis, and enabled real-time detection of sarcomere contraction in monolayered beating cardiomyocytes. Our findings provide a wide range of applications for targeted genome replacement in non-dividing cardiomyocytes.

Background An association between uric acid (UA) and cardiovascular diseases, including heart failure (HF), has been reported. However, whether UA is a causal risk factor for HF is controversial. In particular, the prognostic value of lowering UA in patients with HF with preserved ejection fraction (HFpEF) is unclear. Methods and Results We enrolled patients with HFpEF from the PURSUIT‐HFpEF (Prospective Multicenter Observational Study of Patients With Heart Failure With Preserved Ejection Fraction) registry. We investigated whether UA was correlated with the composite events, including all‐cause mortality and HF rehospitalization, in patients with hyperuricemia and HFpEF (UA >7.0 mg/dL). Additionally, we evaluated whether lowering UA for 1 year (≥1.0 mg/dL) in them reduced mortality or HF rehospitalization. We finally analyzed 464 patients with hyperuricemia. In multivariable Cox regression analysis, UA was an independent determinant of composite death and rehospitalization (hazard ratio [HR], 1.15 [95% CI, 1.03–1.27], P =0.015). We divided them into groups with severe and mild hyperuricemia according to median estimated value of serum UA (8.3 mg/dL). Cox proportional hazards models revealed the incidence of all‐cause mortality was significantly higher in the group with severe hyperuricemia than in the group with mild hyperuricemia (HR, 1.73 [95% CI, 1.19–2.25], P =0.004). The incidence of all‐cause mortality was significantly decreased in the group with lowering UA compared with the group with nonlowering UA (HR, 1.71 [95% CI, 1.02–2.86], P =0.041). The incidence of urate‐lowering therapy tended to be higher in the group with lowering UA than in the group with nonlowering UA (34.9% versus 24.6%, P =0.06). Conclusions UA is a predictor for the composite of all‐cause death and HF rehospitalization in patients with hyperuricemia and HFpEF. In these patients, lowering UA, including the use of urate‐lowering therapy, may improve prognosis.

Aims The effectiveness of angiotensin‐converting enzyme inhibitors (ACE‐I) and angiotensin II receptor blockers (ARB) has not been demonstrated in patients with heart failure with preserved ejection fraction (HFpEF). We recently reported significant interaction between the use of ACE‐I and/or ARB (ACE‐I/ARB) and frailty on prognosis in patients with HFpEF. In the present study, we examined the association between ACE‐I/ARB and prognosis in patients with HFpEF stratified by the presence or absence of frailty. Methods and results We examined the association between the use of ACE‐I/ARB and prognosis according to the presence [Clinical Frailty Scale (CFS) ≥ 5] or absence (CFS ≤ 4) of frailty in patients with HFpEF in a post hoc analysis of registry data. Primary endpoint was the composite of all‐cause mortality and heart failure admission. Secondary endpoints were all‐cause mortality and heart failure admission. Of 1059 patients, median age was 83 years and 45% were male. Kaplan–Meier analysis showed that the risk of composite endpoint (log‐rank P = 0.001) and all‐cause death (log‐rank P = 0.005) in patients with ACE‐I/ARB was lower in those with CFS ≥ 5, but similar between patients with and without ACE‐I/ARB in patients with CFS ≤ 4 (composite endpoint: log‐rank P = 0.830; all‐cause death: log‐rank P = 0.192). In a multivariable Cox proportional hazards model, use of ACE‐I/ARB was significantly associated with lower risk of the composite endpoint [hazard ratio (HR) = 0.52, 95% confidence interval (CI) = 0.33–0.83, P = 0.005] and heart failure admission (HR = 0.45, 95% CI = 0.25–0.83, P = 0.010) in patients with CFS ≥ 5, but not in patients with CFS ≤ 4 (composite endpoint: HR = 1.41, 95% CI = 0.99–2.02, P = 0.059; heart failure admission: HR = 1.43, 95% CI = 0.94–2.18, P = 0.091). The association between ACE‐I or ARB and prognosis did not significantly differ by CFS (CFS ≤ 4: log‐rank P = 0.562; CFS ≥ 5: log‐rank P = 0.100, for with ACE‐I vs. ARB, respectively). Adjusted HRs for CFS 1–4 were higher than 1.0 but were <1.0 at CFS 5. Conclusions In patients with HFpEF, use of ACE‐I/ARB was associated with better prognosis in patients with frailty as assessed with the CFS, but not in those without frailty.