Rationale: Doxorubicin is an effective chemotherapeutic agent for cancer, but its use is often limited by cardiotoxicity. Doxorubicin causes endoplasmic reticulum (ER) dilation in cardiomyocytes, and we have demonstrated that ER stress plays important roles in the pathophysiology of heart failure. Objective: We evaluated the role of ER stress in doxorubicin-induced cardiotoxicity and examined whether the chemical ER chaperone could prevent doxorubicin-induced cardiac dysfunction. Methods and Results: We confirmed that doxorubicin caused ER dilation in mouse hearts, indicating that doxorubicin may affect ER function. Doxorubicin activated an ER transmembrane stress sensor, activating transcription factor 6, in cultured cardiomyocytes and mouse hearts. However, doxorubicin suppressed the expression of genes downstream of activating transcription factor 6, including X-box binding protein 1. The decreased levels of X-box binding protein 1 resulted in a failure to induce the expression of the ER chaperone glucose-regulated protein 78 which plays a major role in adaptive responses to ER stress. In addition, doxorubicin activated caspase-12, an ER membrane–resident apoptotic molecule, which can lead to cardiomyocyte apoptosis and cardiac dysfunction. Cardiac-specific overexpression of glucose-regulated protein 78 by adeno-associated virus 9 or the administration of the chemical ER chaperone 4-phenylbutyrate attenuated caspase-12 cleavage, and alleviated cardiac apoptosis and dysfunction induced by doxorubicin. Conclusions: Doxorubicin activated the ER stress–initiated apoptotic response without inducing the ER chaperone glucose-regulated protein 78, further augmenting ER stress in mouse hearts. Cardiac-specific overexpression of glucose-regulated protein 78 or the administration of the chemical ER chaperone alleviated the cardiac dysfunction induced by doxorubicin and may facilitate the safe use of doxorubicin for cancer treatment.

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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.

the clinical setting. 2,3 Therefore, cardioprotective therapy against AMI remains one of the most important unmet medical needs. 4 Erythropoietin (EPO), a hematopoietic hormone, has antiapoptotic and tissue-protective effects. 5 In animal models, we and others have demonstrated that intravenous administration of EPO associated with reperfusion therapy decreases myocardial infarct size, prevents cardiac E arly reperfusion therapy with percutaneous coronary intervention (PCI) has improved the clinical outcomes of patients with acute myocardial infarction (AMI). Background: Erythropoietin (EPO) has antiapoptotic and tissue-protective effects, but previous clinical studies using high-dose EPO have not shown cardioprotective effects, probably because of platelet activation and a lack of knowledge regarding the optimal dose. In contrast, a small pilot study using low-dose EPO has shown improvement in left ventricular function without adverse cardiovascular events.