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Background and Purpose: Adenosine has been proposed to exert anti-hypertrophic effects. However, the precise regulation and the role of the different adenosine receptor subtypes in the heart and their effects on hypertrophic signalling are largely unknown. We aimed to characterize expression and function of adenosine A1 receptors following hypertrophic stimulation in vitro and in vivo.Experimental Approach: Pro-hypertrophic stimuli and adenosine A1 receptor stimulation of neonatal rat cardiomyocytes and male C57/Bl6 mice, sc. drug administration, real-time PCR, (3) [H]-leucine-incorporation assay, immunostaining, tissue staining, Western blots, gravimetric analyses and echocardiography were applied in this study.Key Results: In neonatal rat cardiomyocyte cultures, phenylephrine, but not angiotensin II or insulin-like growth factor 1 (IGF1), up-regulated adenosine A1 receptors concentration-dependently. The hypertrophic phenotype (cardiomyocyte size, sarcomeric organization, total protein synthesis, c-fos expression) mediated by phenylephrine (10 μM), but not that by angiotensinII (1 μM) or IGF1 (20 ng·mL(-1) ), was counteracted by the selective A1 receptor agonist, N6-cyclopentyladenosine. In C57/BL6 mice, continuous N6-cyclopentyladenosine infusion (2 mg·kg(-1) ·day(-1) ; 21 days) blunted phenylephrine (120 mg·kg(-1) ·day(-1) ; 21 days) induced hypertrophy (heart weight, cardiomyocyte size and fetal genes), fibrosis, MMP 2 up-regulation and generation of oxidative stress - all hallmarks of maladaptive remodelling. Concurrently, phenylephrine administration increased expression of adenosine A1 receptors.Conclusions and Implications: We have presented evidence for a negative feedback mechanism attenuating pathological myocardial hypertrophy following α1 -adrenoceptor stimulation. Our results suggest adenosine A1 receptors as potential targets for therapeutic strategies to prevent transition from compensated myocardial hypertrophy to decompensated heart failure due to chronic cardiac pressure overload. [ABSTRACT FROM AUTHOR]

An abstract of the article "Free Radical Release in Human Failing Myocardium Is Associated With Increased Activity of Rac1-GTPase and Can Be Inhibited by Statin Treatment," by U. Laufs and colleagues is presented.

Background The burden of cancer in heart failure with reduced ejection fraction is apparently growing. Randomized controlled trials (RCTs) may help understanding this observation, since they span decades of heart failure treatment. Methods and Results We assessed cancer, cardiovascular, and total mortality in phase 3 heart failure RCTs involving ≥90% individuals with left ventricular ejection fraction <45%, who were not acutely decompensated and did not represent specific patient subsets. The pooled odds ratios (ORs) of each type of death for the control and treatment arms were calculated using a random-effects model. Temporal trends and the impact of patient and RCT characteristics on mortality outcomes were evaluated by meta-regression analysis. Cancer mortality was reported for 15 (25%) of 61 RCTs, including 33 709 subjects, and accounted for 6% to 14% of all deaths and 17% to 67% of noncardiovascular deaths. Cancer mortality rate was 0.58 (95% CI, 0.46-0.71) per 100 patient-years without temporal trend ( P =0.35). Cardiovascular ( P =0.001) and total ( P =0.001) mortality rates instead decreased over time. Moreover, cancer mortality was not influenced by treatment (OR, 1.08; 95% CI, 0.92-1.28), unlike cardiovascular (OR, 0.88; 95% CI, 0.79-0.98) and all-cause (OR, 0.91; 95% CI, 0.84-0.99) mortality. Meta-regression did not reveal significant sources of heterogeneity. Possible reasons for excluding patients with malignancy overlapped among RCTs with and without published cancer mortality, and malignancy was an exclusion criterion only for 4 (8.7%) of the RCTs not reporting cancer mortality. Conclusions Cancer is a major, yet overlooked cause of noncardiovascular death in heart failure with reduced ejection fraction, which has become more prominent with cardiovascular mortality decline.

Myocardial infarction causes rapid impairment of left ventricular function and requires a hypercontractile response of non-infarcted tissue areas to maintain haemodynamic stability. This compensatory adaptation is mediated by humoral, inflammatory and neuronal signals. GLP-1 is an incretin hormone with glucoregulatory and cardioprotective capacities and is secreted in response to nutritional and inflammatory stimuli. Inactivation of GLP-1 is caused by the ubiquitously present enzyme DPP-4. In this study, circulating concentrations of GLP-1 were assessed after myocardial infarction and were evaluated in the light of metabolism, left ventricular contractility and mitochondrial function. Circulating GLP-1 concentrations were markedly increased in patients with acute myocardial infarction. Experimental myocardial infarction by permanent LAD ligation proved sufficient to increase GLP-1 secretion in mice. This took place in a time-dependent manner, which coincided with the capacity of DPP-4 inhibition, by linagliptin, to augment left ventricular contractility in a GLP-1 receptor-dependent manner. Mechanistically, DPP-4 inhibition increased AMPK activity and stimulated the mitochondrial respiratory capacity of non-infarcted tissue areas. We describe a new functional relevance of inflammatory GLP-1 secretion for left ventricular contractility during myocardial infarction., (© 2018 John Wiley & Sons Ltd.)