S-Nitrosylation of ß-Arrestins Biases Receptor Signaling and Confers Ligand Independence.

Most G protein-coupled receptors (GPCRs) signal through both heterotrimeric G proteins and ß-arrestins (ßarr1 and ßarr2). Although synthetic ligands can elicit biased signaling by G protein- vis-à-vis ßarr-mediated transduction, endogenous mechanisms for biasing signaling remain elusive. Here we report that S-nitrosylation of a novel site within ßarr1/2 provides a general mechanism to bias ligand-induced signaling through GPCRs by selectively inhibiting ßarr-mediated transduction. Concomitantly, S-nitrosylation endows cytosolic ßarrs with receptor-independent function. Enhanced ßarr S-nitrosylation characterizes inflammation and aging as well as human and murine heart failure. In genetically engineered mice lacking ßarr2-Cys253 S-nitrosylation, heart failure is exacerbated in association with greatly compromised ß-adrenergic chronotropy and inotropy, reflecting ßarr-biased transduction and ß-adrenergic receptor downregulation. Thus, S-nitrosylation regulates ßarr function and, thereby, biases transduction through GPCRs, demonstrating a novel role for nitric oxide in cellular signaling with potentially broad implications for patho/physiological GPCR function, including a previously unrecognized role in heart failure.

Association between acute myocardial infarction-to-cardiac rupture time and in-hospital mortality risk: a retrospective analysis of multicenter registry data from the Cardiovascular Research Consortium-8 Universities (CIRC-8U).

Despite the known association of cardiac rupture with acute myocardial infarction (AMI), it is still unclear whether the clinical characteristics are associated with the risk of in-hospital mortality in patients with AMI complicated by cardiac rupture. The purpose of this study was to investigate the association between the time of cardiac rupture occurrence and the risk of in-hospital mortality after AMI. We conducted a retrospective analysis of multicenter registry data from eight medical universities in Eastern Japan. From 10,278 consecutive patients with AMI, we included 183 patients who had cardiac rupture after AMI, and examined the incidence of in-hospital deaths during a median follow-up of 26 days. Patients were stratified into three groups according to the AMI-to-cardiac rupture time, namely the > 24-h group (n = 111), 24-48-h group (n = 20), and < 48-h group (n = 52). Cox proportional hazards regression analysis was used to estimate the hazard ratio (HR) and the confidence interval (CI) for in-hospital mortality. Around 87 (48%) patients experienced in-hospital death and 126 (67%) underwent a cardiac surgery. Multivariable Cox regression analysis revealed a non-linear association across the three groups for mortality (HR [CI]; < 24 h: 1.0, reference; 24-48 h: 0.73 [0.27-1.86]; > 48 h: 2.25 [1.22-4.15]) after adjustments for age, sex, Killip classification, percutaneous coronary intervention, blood pressure, creatinine, peak creatine kinase myocardial band fraction, left ventricular ejection fraction, and type of rupture. Cardiac surgery was independently associated with a reduction in the HR of mortality (HR [CI]: 0.27 [0.12-0.61]) and attenuated the association between the three AMI-to-cardiac rupture time categories and mortality (statistically non-significant) in the Cox model. These data suggest that the AMI-to-cardiac rupture time contributes significantly to the risk of in-hospital mortality; however, rapid diagnosis and prompt surgical interventions are crucial for improving outcomes in patients with cardiac rupture after AMI.

Distinct roles of resident and nonresident macrophages in nonischemic cardiomyopathy.

Nonischemic cardiomyopathy (NICM) resulting from long-standing hypertension, valvular disease, and genetic mutations is a major cause of heart failure worldwide. Recent observations suggest that myeloid cells can impact cardiac function, but the role of tissue-intrinsic vs. tissue-extrinsic myeloid cells in NICM remains poorly understood. Here, we show that cardiac resident macrophage proliferation occurs within the first week following pressure overload hypertrophy (POH; a model of heart failure) and is requisite for the heart's adaptive response. Mechanistically, we identify Kruppel-like factor 4 (KLF4) as a key transcription factor that regulates cardiac resident macrophage proliferation and angiogenic activities. Finally, we show that blood-borne macrophages recruited in late-phase POH are detrimental, and that blockade of their infiltration improves myocardial angiogenesis and preserves cardiac function. These observations demonstrate previously unappreciated temporal and spatial roles for resident and nonresident macrophages in the development of heart failure.

A multicenter study on the clinical characteristics and risk factors of in-hospital mortality in patients with mechanical complications following acute myocardial infarction.

Mechanical complications (MCs) following acute myocardial infarction (AMI), such as ventricular septal rupture (VSR), free-wall rupture (FWR), and papillary muscle rupture (PMR), are fatal. However, the risk factors of in-hospital mortality among patients with MCs have not been previously reported in Japan. The purpose of this study was to evaluate the prognostic factors of in-hospital mortality in these patients. The study cohort consisted of 233 consecutive patients with MCs from the registry of 10 facilities in the Cardiovascular Research Consortium-8 Universities (CIRC-8U) in East Japan between 1997 and 2014 (2.3% of 10,278 AMI patients). The authors conducted a retrospective observational study to analyse the correlation between the subtypes of MCs with in-hospital mortality, clinical data, and medical treatment. We observed a decreasing incidence of MC (1997-2004: 3.7%, 2005-2010: 2.1%, 2011-2014: 1.9%, p < 0.001). In-hospital mortality among patients with MCs was 46%. Thirty-three percent of patients with MCs were not able to undergo surgical repair due to advanced age or severe cardiogenic shock. In-hospital mortality among patients who had undergone surgical repair was 29% (VSR: 21%, FWR: 33%, PMR: 60%). In patients with MCs, hazard ratio for in-hospital mortality according to multivariate analysis of without surgical repair was 5.63 (95% CI 3.54-8.95). In patients with surgical repair, the hazard ratios of blow-out-type FWR (5.53, 95% confidence interval (CI) 2.22-13.76), those with renal dysfunction (3.11, 95% CI 1.37-7.05), and those receiving venoarterial extracorporeal membrane oxygenation (VA-ECMO) (3.79, 95% CI 1.81-7.96) were significantly high. Although primary percutaneous coronary intervention (PCI) is associated with decreased incidence of MCs, high in-hospital mortality persisted in patients with MCs that also presented with renal dysfunction and in those requiring VA-ECMO. Early detection and surgical repair of MCs are essential.

Percutaneous Coronary Intervention for Septic Emboli in the Left Main Trunk as a Complication of Infective Endocarditis.

Infective endocarditis (IE) complicated by acute myocardial infarction (AMI) is frequently fatal and may require emergent interventions. However, the optimal treatment of this rare condition remains controversial as it lacks established guidelines. We successfully treated a patient with IE complicated by AMI during the acute phase using percutaneous coronary intervention (PCI) followed by surgery. A 73-year-old man was diagnosed with IE of the mitral and aortic valves caused by Streptococcus oralis. Four weeks after the initiation of antibiotics sensitive to the causative bacteria, he suddenly developed AMI manifested by chest pain and dyspnoea with cardiovascular collapse. Emergent coronary angiography revealed that the myocardial infarction was secondary to septic emboli in the left main trunk. Emergent PCI comprising aspiration and stent deployment, was successfully performed, and his vital signs were immediately stabilised. He subsequently underwent mitral and aortic valve replacement and debridement without major post-operative complications. Although the optimal treatment strategy for haemodynamically unstable AMI secondary to IE requires further discussion, the present case indicates the importance of early diagnosis and the potential effectiveness of aggressive PCI as a bridge to the following surgery.

Premature Acute Myocardial Infarction in a Young Patient With Sitosterolemia.

Sitosterolemia is a rare, inherited, autosomal recessive disorder of lipid metabolism characterized by increased levels of plant sterols, such as sitosterol and campesterol, xanthomas, and accelerated atherosclerosis. In a 15-year-old boy exhibiting ST-elevation acute myocardial infarction, lipid panels, including plant sterol, and genetic testing for the ATP-binding cassette sub-family G member 5 (ABCG5) gene mutation, confirmed the diagnosis of sitosterolemia. A comprehensive lipid panel and genetic testing should be considered in patients with premature coronary artery disease to prevent disease progression through dietary and pharmacologic interventions specific to sitosterolemia.

La sitostérolémie est une maladie génétique rare à transmission autosomique récessive touchant le métabolisme des lipides, qui est caractérisée par une augmentation des taux de stérols végétaux comme le sitostérol et le campestérol, la présence de xanthomes et une athérosclérose accélérée. Chez un garçon âgé de 15 ans ayant subi un infarctus aigu du myocarde avec élévation du segment ST, le diagnostic de sitostérolémie a été confirmé par un bilan lipidique comprenant un dosage des stérols d'origine végétale et un test génétique de dépistage de la mutation du gène ABCG5 (ATP-binding cassette sub-family G member 5). Un bilan lipidique exhaustif et un test génétique doivent être envisagés chez les patients présentant une coronaropathie prématurée afin de prévenir la progression de la maladie grâce à des interventions d'ordre tant diététique que pharmacologique propres à la sitostérolémie.

Clinical and procedure characteristics in patients treated with polytetrafluoroethylene-covered stents after coronary perforation: a CIRC-8U multicenter registry and literature review.

This study aimed at identifying the clinical characteristics and in-hospital outcomes of patients treated with polytetrafluorethylene (PTFE)-covered stents after coronary interventions in a multicenter registry. Subjects with coronary artery perforation were selected from 31,262 consecutive patients who underwent coronary interventions in the hospital registries. Subjects were divided into two groups: those with a PTFE-covered stent implantation and those without a PTFE-covered stent implantation. Clinical characteristics and in-hospital outcomes were compared between the two groups. Data for 82 consecutive coronary perforations (15 PTFE-covered stents and 67 non-PTFE-covered stents) were extracted from each hospital registry. The PTFE-covered stent group had a higher prevalence of perforations due to pre-dilatation before stenting or post-dilatation after stenting (80% vs. 10.4%; p < 0.001), more Ellis classification III perforations (66.6% vs. 28.4%; p = 0.019), longer perforation to hemostasis time (74 min vs. 10 min; p < 0.001), lower hemostatic success rates (73.3% vs. 94.0%; p = 0.015), and higher in-hospital mortality (26.7% vs. 6.0%; p = 0.015) than the non-PTFE-covered stent group. Although the prevalence of intravascular ultrasound (IVUS) usage was high during coronary interventions (86.7%), IVUS was performed in less than half the cases just before coronary perforations (47%) in the PTFE-covered stent group. Patients requiring PTFE-covered stents are more likely to be observed after balloon dilatation before or after stenting and have a poor prognosis. Careful coronary intervention is needed when IVUS image acquisition is not achieved in addition to proper evaluation of IVUS. Furthermore, if coronary artery perforation occurs, it is important to determine the need for a prompt PTFE-covered stent.

Shortened acquisition time in simultaneous 99mTc-tetrofosmin and 123I-ß-methyl-p-iodophenyl pentadecanoic acid dual-tracer imaging with cadmium-zinc-telluride detectors in patients undergoing primary coronary intervention for acute myocardial infarction.

OBJECTIVE: The use of cadmium-zinc-telluride-based scanners may increase the clinical feasibility of simultaneous dual-isotope imaging. In the current study, we sought to investigate a potential acquisition time in simultaneous Tc-tetrofosmin/I-ß-methyl-p-iodophenyl pentadecanoic acid dual-isotope imaging using a Discovery NM/CT 670 cadmium-zinc-telluride. METHODS: Simultaneous Tc-tetrofosmin/I-ß-methyl-p-iodophenyl pentadecanoic acid dual-isotope imaging was performed in 29 patients who had undergone primary percutaneous coronary intervention for acute myocardial infarction. Referenced images with an acquisition time of 65 s/view (16.25 min) were reframed to produce images with acquisition times of 33, 16, and 8 s/view. The values for the quantitative-gated single-photon emission computed tomography (SPECT) and the quantitative perfusion SPECT were compared. RESULTS: The quantitative-gated SPECT values for images with 33, 16, and 8 s/views showed good consistency with those for 65 s/view (the lower 95% confidence intervals for the intraclass correlation were ≥0.80). The quantitative perfusion SPECT values for Tc-tetrofosmin images with 33, 16, and 8 s/views also showed good consistency with those for 65 s/view; however, the quantitative perfusion SPECT values for I-ß-methyl-p-iodophenyl pentadecanoic acid images with an acquisition time of 8 s/view were not consistent with the reference acquisition time of 65 s/view. CONCLUSIONS: The quantitative-gated SPECT and quantitative perfusion SPECT values obtained from images with shorter acquisition times correlated with the values obtained from images with a reference acquisition time of 65 s/view; however, tracer-specific predisposition should be considered. These findings suggest that it is possible to reduce acquisition time when performing simultaneous Tc-tetrofosmin/I-ß-methyl-p-iodophenyl pentadecanoic acid dual-tracer imaging with the novel cadmium-zinc-telluride scanner.

Successful Bridge-to-Recovery Treatment in a Young Patient with Fulminant Eosinophilic Myocarditis: Roles of a Percutaneous Ventricular Assist Device and Endomyocardial Biopsy.

Eosinophilic myocarditis (EM) is a rare condition characterized by myocardial eosinophilic infiltration due to various underlying etiologies. The patient with EM may benefit from appropriate use of mechanical circulatory support (MCS) that acts as a bridge to myocardial recovery in response to effective immunosuppressive therapy. A 16-year-old boy presented with cardiogenic shock due to fulminant myocarditis, for which a percutaneous ventricular assist device (PVAD) was immediately inserted. Based on the histological diagnosis of EM, immunosuppressive therapy was immediately commenced, leading to improvement of left-ventricular ejection fraction (27% to 47%). The PVAD was successfully removed on day 7. Cardiac magnetic resonance imaging and dual-tracer myocardial scintigraphy suggested limited extent of irreversible myocardial damage. For fulminant EM, the short-term use of PVAD, together with immunosuppressive therapy guided by an immediate histological investigation, may be an effective bridging strategy to myocardial recovery.

Kruppel-like factor 15 is required for the cardiac adaptive response to fasting.

Cardiac metabolism is highly adaptive in response to changes in substrate availability, as occur during fasting. This metabolic flexibility is essential to the maintenance of contractile function and is under the control of a group of select transcriptional regulators, notably the nuclear receptor family of factors member PPARα. However, the diversity of physiologic and pathologic states through which the heart must sustain function suggests the possible existence of additional transcriptional regulators that play a role in matching cardiac metabolism to energetic demand. Here we show that cardiac KLF15 is required for the normal cardiac response to fasting. Specifically, we find that cardiac function is impaired upon fasting in systemic and cardiac specific Klf15-null mice. Further, cardiac specific Klf15-null mice display a fasting-dependent accumulation of long chain acylcarnitine species along with a decrease in expression of the carnitine translocase Slc25a20. Treatment with a diet high in short chain fatty acids relieves the KLF15-dependent long chain acylcarnitine accumulation and impaired cardiac function in response to fasting. Our observations establish KLF15 as a critical mediator of the cardiac adaptive response to fasting through its regulation of myocardial lipid utilization.

Ultrasound-guided Intracardiac Injection of Human Mesenchymal Stem Cells to Increase Homing to the Intestine for Use in Murine Models of Experimental Inflammatory Bowel Diseases.

Crohn's disease (CD) is a common chronic inflammatory disease of the small and large intestines. Murine and human mesenchymal stem cells (MSCs) have immunosuppressive potential and have been shown to suppress inflammation in mouse models of intestinal inflammation, even though the route of administration can limit their homing and effectiveness 1,3,4,5. Local application of MSCs to colonic injury models has shown greater efficacy at ameliorating inflammation in the colon. However, there is paucity of data on techniques to enhance the localization of human bone marrow-derived MSCs (hMSCs) to the small intestine, the site of inflammation in the SAMP-1/YitFc (SAMP) model of experimental Crohn's disease. This work describes a novel technique for the ultrasound-guided intracardiac injection of hMSCs in SAMP mice, a well-characterized spontaneous model of chronic intestinal inflammation. Sex- and age-matched, inflammation-free AKR/J (AKR) mice were used as controls. To analyze the biodistribution and the localization, hMSCs were transduced with a lentivirus containing a triple reporter. The triple reporter consisted of firefly luciferase (fl), for bioluminescent imaging; monomeric red fluorescent protein (mrfp), for cell sorting; and truncated herpes simplex virus thymidine kinase (ttk), for positron emission tomography (PET) imaging. The results of this study show that 24 h after the intracardiac administration, hMSCs localize in the small intestine of SAMP mice as opposed to inflammation-free AKR mice. This novel, ultrasound-guided injection of hMSCs in the left ventricle of SAMP mice ensures a high success rate of cell delivery, allowing for the rapid recovery of mice with minimal morbidity and mortality. This technique could be a useful method for the enhanced localization of MSCs in other models of small-intestinal inflammation, such as TNFΔRE6. Future studies will determine if the increased localization of hMSCs by intra-arterial delivery can lead to increased therapeutic efficacy.

REV-ERBα ameliorates heart failure through transcription repression.

A cure for heart failure remains a major unmet clinical need, and current therapies targeting neurohomonal and hemodynamic regulation have limited efficacy. The pathological remodeling of the myocardium has been associated with a stereotypical gene expression program, which had long been viewed as the consequence and not the driver of the disease until very recently. Despite the advance, there is no therapy available to reverse the already committed gene program. Here, we demonstrate that transcriptional repressor REV-ERB binds near driver transcription factors across the genome. Pharmacological activation of REV-ERB selectively suppresses aberrant pathologic gene expression and prevents cardiomyocyte hypertrophy. In vivo, REV-ERBα activation prevents development of cardiac hypertrophy, reduces fibrosis, and halts progression of advanced heart failure in mouse models. Thus, to our knowledge, modulation of gene networks by targeting REV-ERBα represents a novel approach to heart failure therapy.

KLF2 and KLF4 control endothelial identity and vascular integrity.

Maintenance of vascular integrity in the adult animal is needed for survival, and it is critically dependent on the endothelial lining, which controls barrier function, blood fluidity, and flow dynamics. However, nodal regulators that coordinate endothelial identity and function in the adult animal remain poorly characterized. Here, we show that endothelial KLF2 and KLF4 control a large segment of the endothelial transcriptome, thereby affecting virtually all key endothelial functions. Inducible endothelial-specific deletion of Klf2 and/or Klf4 reveals that a single allele of either gene is sufficient for survival, but absence of both (EC-DKO) results in acute death from myocardial infarction, heart failure, and stroke. EC-DKO animals exhibit profound compromise in vascular integrity and profound dysregulation of the coagulation system. Collectively, these studies establish an absolute requirement for KLF2/4 for maintenance of endothelial and vascular integrity in the adult animal.

The effect of adaptive servo-ventilation on dyspnoea, haemodynamic parameters and plasma catecholamine concentrations in acute cardiogenic pulmonary oedema.

BACKGROUND: Adaptive servo-ventilation has a potential sympathoinhibitory effect in acute cardiogenic pulmonary oedema (ACPO). AIMS: To evaluate the acute effects of adaptive servo-ventilation in patients with ACPO. METHODS: Fifty-eight consecutive patients with ACPO were divided into those who underwent adaptive servo-ventilation and those who received oxygen therapy alone as part of their immediate care. Visual analogue scale, vital signs, blood gas data and plasma catecholamine concentrations at baseline and 1 h during emergency care, and subsequent clinical events (death within 30 days, intubation within seven days or between seven and 30 days, and length of hospital stay) were assessed. Pre-matched and post-propensity score (PS)-matched datasets were analysed. RESULTS: During the first hour of adaptive servo-ventilation, plasma catecholamine concentrations fell significantly (baseline versus 1 h: epinephrine p = 0.003, norepinephrine p < 0.001, dopamine p < 0.001), with falls in blood pressure, heart rate, respiratory rate and pCO2, and rise in HCO3 and pH. In the PS-matched model, visual analogue scale (p = 0.036), systolic blood pressure (from 153.8 ± 30.7 to 133.1 ± 16.3 mmHg; p = 0.025) and plasma dopamine concentration (p = 0.034) fell significantly in the adaptive servo-ventilation group compared with the oxygen therapy alone group. The clinical outcomes between the groups were comparable. CONCLUSION: In patients with ACPO, emergency care using adaptive servo-ventilation attenuated plasma catecholamine concentrations and led to the improvement of dyspnoea, vital signs and acid-base balance, without adversely influencing clinical outcomes. Using adaptive servo-ventilation, rather than standard oxygen alone, may relieve dyspnoea and improve haemodynamic status, possibly by modulating sympathetic nerve activity.

Improved myocardial strain measured by strain-encoded magnetic resonance imaging in a patient with cardiac sarcoidosis.

A woman aged 64 years with cardiac sarcoidosis responded favourably to corticosteroid therapy in terms of recovered longitudinal myocardial strain, as evaluated by strain-encoded magnetic resonance imaging (SENC-MRI). In contrast, circumferential myocardial strain and late gadolinium enhancement demonstrated minimal improvement, suggesting relatively advanced pathology of the myocardial middle layer. We propose SENC-MRI as a marker of disease at an early stage of cardiac sarcoidosis.