Although the precise pathogenesis of diabetic cardiac damage remains unclear, potential mechanisms include increased oxidative stress, autonomic nervous dysfunction, and altered cardiac metabolism. Thioredoxin-interacting protein (Txnip) was initially identified as an inhibitor of the antioxidant thioredoxin but is now recognized as a member of the arrestin superfamily of adaptor proteins that classically regulate G protein-coupled receptor signaling. Here we show that Txnip plays a key role in diabetic cardiomyopathy. High glucose levels induced Txnip expression in rat cardiomyocytes in vitro and in the myocardium of streptozotocin-induced diabetic mice in vivo. While hyperglycemia did not induce cardiac dysfunction at baseline, β-adrenergic challenge revealed a blunted myocardial inotropic response in diabetic animals (24-wk-old male and female C57BL/6;129Sv mice). Interestingly, diabetic mice with cardiomyocyte-specific deletion of Txnip retained a greater cardiac response to β-adrenergic stimulation than wild-type mice. This benefit in Txnip-knockout hearts was not related to the level of thioredoxin activity or oxidative stress. Unlike the β-arrestins, Txnip did not interact with β-adrenergic receptors to desensitize downstream signaling. However, our proteomic and functional analyses demonstrated that Txnip inhibits glucose transport through direct binding to glucose transporter 1 (GLUT1). An ex vivo analysis of perfused hearts further demonstrated that the enhanced functional reserve afforded by deletion of Txnip was associated with myocardial glucose utilization during β-adrenergic stimulation. These data provide novel evidence that hyperglycemia-induced Txnip is responsible for impaired cardiac inotropic reserve by direct regulation of insulin-independent glucose uptake through GLUT1 and plays a role in the development of diabetic cardiomyopathy.
MitraClip therapy provides improvements in physical capacity, physical and mental functioning and disease-specific quality of life in the majority of patients. However, more comparative and high-quality studies are required for understanding the heterogeneity of results, which is crucial for optimal patient selection.
Background: The aim of the present study was to analyze incidence, risk factors, and association with long-term outcome of postoperative delirium (POD) after transcatheter aortic valve replacement (TAVR).Methods: Six hundred and sixty one consecutive patients undergoing TAVR were prospectively enrolled from January 2016 to December 2017. POD was assessed regularly during ICU-stay using the CAM-ICU test.Results: The incidence of POD was 10.0% (n = 66). Patients developing POD were predominantly male (65%), had higher EuroSCORE II (5.4% vs. 3.9%; P = 0.041) and were more often considered frail (70% vs. 26%; P < 0.001). POD was associated with more peri-procedural complications including vascular complications (19.7 vs. 9.4; P = 0.017), bleeding (12.1 vs. 5.4%; P = 0.0495); stroke (4.5 vs. 0.7%; P = 0.025), respiratory failure requiring ventilation (16.7% vs. 1.8%; P < 0.001), and pneumonia (34.8% vs. 7.1%; P < 0.001). Consequently, patients with POD had significantly longer ICU- (7.9 vs. 3.2 days P < 0.001) and hospital-stay (14.9 vs. 9.0 days; P < 0.001), and higher in-hospital mortality (6.1 vs. 2.1%; P = 0.017). Logistic regression analysis identified male sex (odds ratio (OR) 2.2 [95% confidence interval (CI) 1.2–4.0); P = 0.012], atrial fibrillation [OR 3.0 (CI 1.6–5.6); P < 0.001], frailty [OR 4.3 (CI 2.4–7.9); P < 0.001], pneumonia [OR 4.4 (CI 2.3–8.7); P < 0.001], stroke [OR 7.0 (CI 1.2–41.6); P = 0.031], vascular complication [OR 2.9 (CI 1.3–6.3); P = 0.007], and general anesthesia [OR 2.0 (CI 1.0–3.7); P = 0.039] as independent predictors of POD. On Cox proportional hazard analysis POD emerged as a significant predictor of 2-year mortality [HR 1.89 (CI 1.06–3.36); P = 0.030].Conclusion: POD is a frequent finding after TAVR and is significantly associated with reduced 2-year survival. Predictors of delirium include not only peri-procedural parameters like stroke, pneumonia, vascular complications and general anesthesia but also baseline characteristics as male sex, atrial fibrillation and frailty.
Heart failure is one of the most common medical diseases-almost every third 55-year-old person in the Western world is going to develop heart failure in his or her life. The development of heart failure is associated with pivotal restructuring of the beta-adrenergic system. The beta-adrenoceptor antagonists have emerged to be an essential part of the therapy of chronic heart failure. Three different beta-adrenoceptors could be identified and characterized so far. The beta1-adrenoceptors are being down-regulated, while the beta3-adrenoceptors are being up-regulated. The mechanisms that are responsible for the positive impact of beta-adrenoceptor antagonists are not completely understood up to now. Therefore, it is necessary to point out the crucial role of the beta-adrenergic system for the regulation of the cardiovascular system and the pathogenesis of heart failure. In the recent couple of years, numerous transgenic mouse models have proven to be helpful to gain a better understanding of the function and the relevance of these receptors. This review gives an overview of the pathophysiological relevance of the beta-adrenergic system for heart failure and outlines the most important insights concerning heart function, which could be derived from genetically changed mice with chronic deficiency and overexpression of the beta-adrenoceptor.
Nitro-fatty acids are electrophilic anti-inflammatory mediators which are generated during myocardial ischemic injury. Whether these species exert anti-arrhythmic effects in the acute phase of myocardial ischemia has not been investigated so far. Herein, we demonstrate that pretreatment of mice with 9- and 10-nitro-octadec-9-enoic acid (nitro-oleic acid, NO2-OA) significantly reduced the susceptibility to develop acute ventricular tachycardia (VT). Accordingly, epicardial mapping revealed a markedly enhanced homogeneity in ventricular conduction. NO2-OA treatment of isolated cardiomyocytes lowered the number of spontaneous contractions upon adrenergic isoproterenol stimulation and nearly abolished ryanodine receptor type 2 (RyR2)-dependent sarcoplasmic Ca2+ leak. NO2-OA also significantly reduced RyR2-phosphorylation by inhibition of increased CaMKII activity. Thus, NO2-OA might be a novel pharmacological option for the prevention of VT development.
1. There is evidence that different aetiologies of heart failure, especially ischaemic vs dilated cardiomyopathy (ICM and DCM, respectively), may influence the prognosis of patients with this disease. Patients with ICM have a worse prognosis than those with DCM; the mechanisms underlying this difference have not yet been clarified. The aim of the present study was to investigate whether there are changes in myofibrillar function depending on the aetiology of human heart failure. 2. Ca(2+) -dependent tension (DT) and actomyosin ATPase activity (MYO) in Triton X-skinned fibre preparations of the left ventricular myocardium from patients with heart failure due to ICM (n=5) and DCM (n=5) were measured. Tension-dependent ATP consumption was calculated by the ratio of DT and MYO ('tension cost'). Non-failing myocardium (NF) from donor hearts, which could not be transplanted because of technical reasons, was evaluated as a control. 3. Although DT was reduced, the myofibrillar Ca(2+) sensitivity of DT and MYO, as well as tension cost, were increased in preparations from ICM and DCM myocardium compared with NF. The Ca(2+) sensitivity of DT and MYO was significantly increased in ICM compared with DCM preparations, resulting in more economic cross-bridge cycling in ICM than in DCM. 4. In conclusion, ICM is associated with an increased Ca(2+) sensitivity of myofibrillar tension and ATPase activity accompanied by decreased tension cost compared with DCM. Thus, the worse prognosis associated with ICM does not seem to be due to differences in myofibrillar function.
Objectives This study aimed to compare hemodynamic characteristics of different self-expanding (SE) and balloon-expandable (BE) transcatheter heart valves (THV) in relation to native aortic annulus anatomy. Background A patient centered THV selection becomes increasingly important as indications for transcatheter aortic valve replacement (TAVR) are extended towards lower risk populations. Methods Hemodynamic parameters including mean gradient (MG), effective orifice area (EOA), Doppler velocity index (DVI), degree of paravalvular regurgitation (PVR) and patient-prosthesis mismatch (PPM) were compared by valve type, label size and in relation to quintiles of native aortic annulus area. Results 2609 patients were treated at 3 centers in Germany with SAPIEN 3 (n = 1146), ACURATE Neo (n = 649), Evolut R (n = 546) or Evolut Pro (n = 268) THV. SE THVs provided superior hemodynamics in terms of larger EOA, higher DVI and lower MG compared to BE THV, especially in patients with small aortic annuli. Severe PPM was less frequent in SE treated patients. The rate of PVR ≥ moderate was comparable for SE and BE devices in smaller annular dimensions, but remarkably lower for BE TAVR in large aortic annular dimensions (> 547.64 mm2) (2% BE THV vs. > 10% for SE THV; p < 0.001). Conclusions Patients with small aortic annular dimensions may benefit hemodynamically from SE THV. With increasing annulus size, BE THV may have advantages since PVR ≥ moderate occurs less frequently. Graphical abstract
AimsThe impact of type of first medical contact (FMC) in the setting of a guideline conform metropolitan ST-elevation myocardial infarction (STEMI) network providing obligatory primary percutaneous coronary intervention (PCI) is unclear.Methods and Results3,312 patients were prospectively included between 2006 and 2012 into a registry accompanying the “Cologne Infarction Model” STEMI network, with 68.4% primarily presenting to emergency medical service (EMS), 17.6% to non-PCI-capable hospitals, and 14.0% to PCI-capable hospitals. Median contact-to-balloon time differed significantly by FMC with 89 minutes (IQR 72–115) for EMS, 107 minutes (IQR 85–148) for non-PCI- and 65 minutes (IQR 48–91) for PCI-capable hospitals (p < 0.001). TIMI-flow grade III and in-hospital mortality were 75.7% and 10.4% in EMS, 70.3% and 8.6% in non-PCI capable hospital and 84.4% and 5.6% in PCI-capable hospital presenters, respectively (p both < 0.01). The association of FMC with in-hospital mortality was not significant after adjustment for baseline characteristics, but risk of TIMI-flow grade < III remained significantly increased in patients presenting to non-PCI capable hospitals.ConclusionDespite differences in treatment delay by type of FMC in-hospital mortality did not differ significantly. The increased risk of TIMI-flow grade < III in patients presenting to non PCI-capable hospitals needs further study.
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