Transcatheter Aortic Valve Replacement After Prior Mitral Valve Surgery: Results From the Transcatheter Valve Therapy Registry.

BACKGROUND: Due to perceived technical challenges, patients with previous surgical mitral valve repair or replacement (SMVR) have been excluded from most transcatheter aortic valve replacement (TAVR) trials. Our objective was to compare the 30-day and 1-year outcomes of TAVR for patients with and without prior SMVR. METHODS: In a retrospective review of The Society of Thoracic Surgeons (STS) and American College of Cardiology (ACC) Transcatheter Valve Therapy (TVT) Registry, we compared 1097 patients with prior SMVR to 46,327 patients without prior SMVR who underwent TAVR between November 2011 and September 2015 at 394 US centers. Preoperative characteristics, procedural details, and clinical outcomes were analyzed. RESULTS: Patients with previous SMVR were younger, more often female, and had higher STS predicted risk of mortality (8.6% vs 6.8%, P < .001). However, there was no difference in 30-day mortality (4.6% vs 5.5%, P = .293), myocardial infarction, stroke, reintervention, new dialysis, or readmission. Moderate/severe paravalvular leak at discharge was also similar (5.8% vs 4.9%, P = .343). At 1 year, morbidity was similar with slightly higher mortality among patients with prior SMVR (20% vs 17.5%, P = .087) that was significant after adjustment (hazard ratio 1.18, P = .043). The type of prior SMVR (repair, bioprosthetic replacement, or mechanical replacement) had no impact on 30-day or 1-year survival. CONCLUSIONS: Patients with prior SMVR undergoing TAVR had similar 30-day outcomes, slightly higher 1-year mortality, and no increase in early paravalvular leak compared with patients who did not have previous SMVR. Prior SMVR should not preclude TAVR for appropriately selected patients.

Model based on GA and DNN for prediction of mRNA-Smad7 expression regulated by miRNAs in breast cancer.

BACKGROUND: The Smad7 protein is negative regulator of the TGF-ß signaling pathway, which is upregulated in patients with breast cancer. miRNAs regulate proteins expressions by arresting or degrading the mRNAs. The purpose of this work is to identify a miRNAs profile that regulates the expression of the mRNA coding for Smad7 in breast cancer using the data from patients with breast cancer obtained from the Cancer Genome Atlas Project. METHODS: We develop an automatic search method based on genetic algorithms to find a predictive model based on deep neural networks (DNN) which fit the set of biological data and apply the Olden algorithm to identify the relative importance of each miRNAs. RESULTS: A computational model of non-linear regression is shown, based on deep neural networks that predict the regulation given by the miRNA target transcripts mRNA coding for Smad7 protein in patients with breast cancer, with R2 of 0.99 is shown and MSE of 0.00001. In addition, the model is validated with the results in vivo and in vitro experiments reported in the literature. The set of miRNAs hsa-mir-146a, hsa-mir-93, hsa-mir-375, hsa-mir-205, hsa-mir-15a, hsa-mir-21, hsa-mir-20a, hsa-mir-503, hsa-mir-29c, hsa-mir-497, hsa-mir-107, hsa-mir-125a, hsa-mir-200c, hsa-mir-212, hsa-mir-429, hsa-mir-34a, hsa-let-7c, hsa-mir-92b, hsa-mir-33a, hsa-mir-15b, hsa-mir-224, hsa-mir-185 and hsa-mir-10b integrate a profile that critically regulates the expression of the mRNA coding for Smad7 in breast cancer. CONCLUSIONS: We developed a genetic algorithm to select best features as DNN inputs (miRNAs). The genetic algorithm also builds the best DNN architecture by optimizing the parameters. Although the confirmation of the results by laboratory experiments has not occurred, the results allow suggesting that miRNAs profile could be used as biomarkers or targets in targeted therapies.

Predicting the physiological response of Tivela stultorum hearts with digoxin from cardiac parameters using artificial neural networks.

Multi-layer perceptron artificial neural networks (MLP-ANNs) were used to predict the concentration of digoxin needed to obtain a cardio-activity of specific biophysical parameters in Tivela stultorum hearts. The inputs of the neural networks were the minimum and maximum values of heart contraction force, the time of ventricular filling, the volume used for dilution, heart rate and weight, volume, length and width of the heart, while the output was the digoxin concentration in dilution necessary to obtain a desired physiological response. ANNs were trained, validated and tested with the dataset of the in vivo experiment results. To select the optimal network, predictions for all the dataset for each configuration of ANNs were made, a maximum 5% relative error for the digoxin concentration was set and the diagnostic accuracy of the predictions made was evaluated. The double-layer perceptron had a barely higher performance than the single-layer perceptron; therefore, both had a good predictive ability. The double-layer perceptron was able to obtain the most accurate predictions of digoxin concentration required in the hearts of T. stultorum using MLP-ANNs.

Insulin induces IRS2-dependent and GRK2-mediated ß2AR internalization to attenuate ßAR signaling in cardiomyocytes.

The counter-regulatory effects of insulin and catecholamines on carbohydrate and lipid metabolism are well studied, whereas the details of insulin regulation of ß adrenergic receptor (ßAR) signaling pathway in heart remain unknown. Here, we characterize a novel signaling pathway of insulin receptor (IR) to G protein-coupled receptor kinase 2 (GRK2) in the heart. Insulin stimulates recruitment of GRK2 to ß2AR, which induces ß2AR phosphorylation at the GRK sites of serine 355/356 and subsequently ß2AR internalization. Insulin thereby suppresses ßAR-induced cAMP-PKA activities and contractile response in neonatal and adult mouse cardiomyocytes. Deletion of insulin receptor substrate 2 (IRS2) disrupts the complex of IR and GRK2, which attenuates insulin-mediated ß2AR phosphorylation at the GRK sites and ß2AR internalization, and the counter-regulation effects of insulin on ßAR signaling. These data indicate the requirements of IRS2 and GRK2 for insulin to stimulate counter-regulation of ßAR via ß2AR phosphorylation and internalization in cardiomyocytes.

Arrestin orchestrates crosstalk between G protein-coupled receptors to modulate the spatiotemporal activation of ERK MAPK.

RATIONALE: G protein-coupled receptors (GPCRs) respond to diversified extracellular stimuli to modulate cellular function. Despite extensive studies investigating the regulation of single GPCR signaling cascades, the effects of concomitant GPCR activation on downstream signaling and cellular function remain unclear. OBJECTIVE: We aimed to characterize the cellular mechanism by which GPCR crosstalk regulates mitogen-activated protein kinase (MAPK) activation. METHODS AND RESULTS: Adrenergic receptors on cardiac fibroblasts were manipulated to examine the role of arrestin in the spatiotemporal regulation of extracellular signal-regulated kinase (ERK)1/2 MAPK signaling. We show a general mechanism in which arrestin activation by one GPCR is capable of regulating signaling originating from another GPCR. Activation of Gq coupled-receptor signaling leads to prolonged ERK1/2 MAPK phosphorylation, nuclear accumulation, and cellular proliferation. Interestingly, coactivation of these receptors with the beta-adrenergic receptors induced transient ERK signaling localized within the cytosol, which attenuated cell proliferation. Further studies revealed that recruitment of arrestin3 to the beta2-adrenergic receptor orchestrates the sequestration of Gq-coupled receptor-induced ERK to the cytosol through direct binding of ERK to arrestin. CONCLUSIONS: This is the first evidence showing that arrestin3 acts as a coordinator to integrate signals from multiple GPCRs. Our studies not only provide a novel mechanism explaining the integration of mitogenic signaling elicited by different GPCRs, but also underscore the critical role of signaling crosstalk among GPCRs in vivo.

Ibutilide therapy for atrial fibrillation: 5-year experience in a community hospital.

Many institutions restrict the use of ibutilide because of the potential risk of polymorphic ventricular tachycardia (PMVT). Over a 5-year period from June 2000 to May 2005, 238 patients, 151 men and 87 women, with a mean age of 67.1 years (range, 22-94 years), received intravenous ibutilide at our institution. Ibutilide was administered by nurses or physicians in 4 clinical settings: emergency department (n = 80), intensive care unit (n = 11), patient room on telemetry (n = 107), and in the cardiac catheterization/electrophysiology laboratory (n = 40). Conversion to sinus rhythm occurred in 59% of patients outside the catheterization/electrophysiology laboratory. The incidence of PMVT was 1.7%. Three patients had brief nonsustained PMVT and 1 patient had a sustained PMVT. There was no difference in outcome whether a physician was present at the time of ibutilide administration. Our data suggest that ibutilide is a safe and efficacious drug when ordered by experienced physicians in properly selected patients in a variety of monitored settings.