Transcatheter Aortic Valve Implantation in Low-Risk Tricuspid or Bicuspid Aortic Stenosis: The NOTION-2 Trial.

BACKGROUND AND AIMS: Transcatheter aortic valve implantation (TAVI) has become the first choice to treat older patients with severe symptomatic aortic stenosis (AS). This study aimed to compare TAVI with surgery in low-risk patients ≤ 75 years of age, including both tricuspid and bicuspid AS. METHODS: The NOTION-2 trial enrolled and 1:1 randomized low-risk patients aged ≤ 75 years with severe symptomatic AS to TAVI or surgery. The primary endpoint was a composite of all-cause mortality, stroke or rehospitalization (related to the procedure, valve or heart failure) at 12 months. RESULTS: A total of 370 patients were enrolled with a mean age of 71.1 years and a median Society of Thoracic Surgeons risk score of 1.1%. A total of 100 patients had bicuspid AS. The 1-year incidence of the primary endpoint was 10.2% in the TAVI group and 7.1% in the surgery group (absolute risk difference 3.1%; 95% confidence interval [CI], -2.7% to 8.8%; hazard ratio (HR) 1.4, 95% CI: 0.7 to 2.9; p=0.3). Patients with TAVI, when compared to surgery, had lower risk of major bleeding and new-onset atrial fibrillation and higher risk of non-disabling stroke, permanent pacemaker implantation and moderate-or-greater paravalvular regurgitation. The risk of the primary composite endpoint was 8.7% and 8.3% in patients with tricuspid AS (HR 1.0, 95% CI: 0.5 to 2.3) and 14.3% and 3.9% in patients with bicuspid AS (HR 3.8, 95% CI: 0.8 to 18.5) treated with TAVI or surgery, respectively (P for interaction=0.1). CONCLUSIONS: Among low-risk patients aged ≤ 75 years with severe symptomatic AS, the rate of the composite of death, stroke, or rehospitalization at one year was similar between TAVI and surgery. TAVI outcomes in young bicuspid AS patients warrant caution and should be further investigated. (NOTION-2, ClinicalTrials.gov, NCT02825134).

Dasatinib targets c-Src kinase in cardiotoxicity.

Dasatinib is a multitargeted kinase inhibitor used for treatment of chronic myeloid leukemia and acute lymphoblastic leukemia. Unfortunately, treatment of cancer patients with some kinase inhibitors has been associated with cardiotoxicity. Cancer treatment with dasatinib has been reported to be associated with cardiotoxic side effects such as left ventricular dysfunction, heart failure, pericardial effusion and pulmonary hypertension. Here we aimed to investigate the molecular mechanisms underlying the cardiotoxicity of dasatinib. We found that among the resident cardiac cell types, cardiomyocytes were most sensitive to dasatinib-induced cell death. Exposure of cardiomyocytes to dasatinib attenuated the activity of extracellular signal-regulated kinase (ERK), which is a downstream target of dasatinib target kinase c-Src. Similar to dasatinib, c-Src depletion in cardiomyocytes compromised cardiomyocyte viability. Overexpression of dasatinib-resistant mutant of c-Src rescued the toxicity of dasatinib on cardiomyocytes, whereas forced expression of wild type c-Src did not have protective effect. Collectively, our results show that c-Src is a key target of dasatinib mediating the toxicity of dasatinib to cardiomyocytes. These findings may influence future drug design and suggest closer monitoring of patients treated with agents targeting c-Src for possible adverse cardiac effects.

[Adverse cardiac effects associated with anticancer drugs]. / Syöpälääkkeiden sydänhaitat.

With the development of new protein kinases, antibodies, immunomodulators and hormonal treatments, significant progress has taken place in the last few years in the pharmacological treatment of cancers. At the same time, old cytotoxic drugs still remain in use. In regard to the heart, anthracyclines are the most problematic cytotoxic drugs, as they may cause cardiac insufficiency that is manifested only years after the treatment. Also trastuzumab and kinase inhibitors may cause cardiac insufficiency. Fluoropyrimidines cause myocardial ischemia for some patients. Treatments targeting VEGF inhibition are frequently associated with significant elevation of blood pressure.

Endothelin-1 and angiotensin II contribute to BNP but not c-fos gene expression response to elevated load in isolated mice hearts.

The early events in the cardiac hypertrophic process induced by hemodynamic load include activation of B-type natriuretic peptide (BNP) and c-fos gene expression. However, it is unknown whether stretch acts directly or through local paracrine factors to trigger changes in cardiac gene expression. Herein we studied the involvement of endothelin-1 (ET-1) and angiotensin II (Ang II) in load-induced activation of left ventricular BNP and c-fos gene expression using an in vitro stretch model in isolated perfused adult mice hearts. Two-hour stretch induced by increasing coronary flow rate from 2 to 5 ml/min increased the expression of BNP and c-fos genes by 1.9- and 1.5-fold, respectively (P<0.001 and P<0.05). A mixed ET(A/B) receptor antagonist bosentan attenuated the BNP gene expression response to load by 58% (P<0.005). A similar 53% inhibition was observed with the selective ET(A) receptor blocker BQ-123 (P<0.05). Type 1 Ang II receptor antagonist CV-11974 decreased the activation of BNP gene expression by 50% (P<0.05). In contrast, the activation of c-fos gene expression was not inhibited by antagonists of ET(A/B) and AT(1) receptors. Our results show that ET-1 and Ang II play a key role in the induction of BNP, but not c-fos gene expression in response to load in intact adult murine hearts.

Regulated overexpression of the A1-adenosine receptor in mice results in adverse but reversible changes in cardiac morphology and function.

BACKGROUND: Both the A1- and A3-adenosine receptors (ARs) have been implicated in mediating the cardioprotective effects of adenosine. Paradoxically, overexpression of both A1-AR and A3-AR is associated with changes in the cardiac phenotype. To evaluate the temporal relationship between AR signaling and cardiac remodeling, we studied the effects of controlled overexpression of the A1-AR using a cardiac-specific and tetracycline-transactivating factor-regulated promoter. METHODS AND RESULTS: Constitutive A1-AR overexpression caused the development of cardiac dilatation and death within 6 to 12 weeks. These mice developed diminished ventricular function and decreased heart rate. In contrast, when A1-AR expression was delayed until 3 weeks of age, mice remained phenotypically normal at 6 weeks, and >90% of the mice survived at 30 weeks. However, late induction of A1-AR still caused mild cardiomyopathy at older ages (20 weeks) and accelerated cardiac hypertrophy and the development of dilatation after pressure overload. These changes were accompanied by gene expression changes associated with cardiomyopathy and fibrosis and by decreased Akt phosphorylation. Discontinuation of A1-AR induction mitigated cardiac dysfunction and significantly improved survival rate. CONCLUSIONS: These data suggest that robust constitutive myocardial A1-AR overexpression induces a dilated cardiomyopathy, whereas delaying A1-AR expression until adulthood ameliorated but did not eliminate the development of cardiac pathology. Thus, the inducible A1-AR transgenic mouse model provides novel insights into the role of adenosine signaling in heart failure and illustrates the potentially deleterious consequences of selective versus nonselective activation of adenosine-signaling pathways in the heart.

Apelin, the novel endogenous ligand of the orphan receptor APJ, regulates cardiac contractility.

The orphan receptor APJ and its recently identified endogenous ligand, apelin, exhibit high levels of mRNA expression in the heart. However, the functional importance of apelin in the cardiovascular system is not known. In isolated perfused rat hearts, infusion of apelin (0.01 to 10 nmol/L) induced a dose-dependent positive inotropic effect (EC50: 33.1+/-1.5 pmol/L). Moreover, preload-induced increase in dP/dt(max) was significantly augmented (P<0.05) in the presence of apelin. Inhibition of phospholipase C (PLC) with U-73122 and suppression of protein kinase C (PKC) with staurosporine and GF-109203X markedly attenuated the apelin-induced inotropic effect (P<0.001). In addition, zoniporide, a selective inhibitor of Na+-H+ exchange (NHE) isoform-1, and KB-R7943, a potent inhibitor of the reverse mode Na+-Ca2+ exchange (NCX), significantly suppressed the response to apelin (P<0.001). Perforated patch-clamp recordings showed that apelin did not modulate L-type Ca2+ current or voltage-activated K+ currents in isolated adult rat ventricular myocytes. Apelin mRNA was markedly downregulated in cultured neonatal rat ventricular myocytes subjected to mechanical stretch and in vivo in two models of chronic ventricular pressure overload. The present study provides the first evidence for the physiological significance of apelin in the heart. Our results show that apelin is one of the most potent endogenous positive inotropic substances yet identified and that the inotropic response to apelin may involve activation of PLC, PKC, and sarcolemmal NHE and NCX.