Browsing by Author "Drakos, Stavros G."

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    Epigenetic response to environmental stress: Assembly of BRG1–G9a/GLP–DNMT3 repressive chromatin complex on Myh6 promoter in pathologically stressed hearts
    (Elsevier, 2016-03-04) Han, Pei; Li, Wei; Yang, Jin; Shang, Ching; Lin, Chiou-Hong; Cheng, Wei; Hang, Calvin T.; Cheng, Hsiu-Ling; Chen, Chen-Hao; Wong, Johnson; Xiong, Yiqin; Zhao, Mingming; Drakos, Stavros G.; Ghetti, Andrea; Li, Dean Y.; Bernstein, Daniel; Chen, Huei-sheng Vincent; Quertermous, Thomas; Chang, Ching-Pin; Medicine, School of Medicine
    Chromatin structure is determined by nucleosome positioning, histone modifications, and DNA methylation. How chromatin modifications are coordinately altered under pathological conditions remains elusive. Here we describe a stress-activated mechanism of concerted chromatin modification in the heart. In mice, pathological stress activates cardiomyocytes to express Brg1 (nucleosome-remodeling factor), G9a/Glp (histone methyltransferase), and Dnmt3 (DNA methyltransferase). Once activated, Brg1 recruits G9a and then Dnmt3 to sequentially assemble repressive chromatin—marked by H3K9 and CpG methylation—on a key molecular motor gene (Myh6), thereby silencing Myh6 and impairing cardiac contraction. Disruption of Brg1, G9a or Dnmt3 erases repressive chromatin marks and de-represses Myh6, reducing stress-induced cardiac dysfunction. In human hypertrophic hearts, BRG1–G9a/GLP–DNMT3 complex is also activated; its level correlates with H3K9/CpG methylation, Myh6 repression, and cardiomyopathy. Our studies demonstrate a new mechanism of chromatin assembly in stressed hearts and novel therapeutic targets for restoring Myh6 and ventricular function. The stress-induced Brg1–G9a–Dnmt3 interactions and sequence of repressive chromatin assembly on Myh6 illustrates a molecular mechanism by which the heart epigenetically responds to environmental signals. This article is part of a Special Issue entitled: Cardiomyocyte Biology: Integration of Developmental and Environmental Cues in the Heart edited by Marcus Schaub and Hughes Abriel.
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    Use of a Pulmonary Artery Pressure Sensor to Manage Patients With Left Ventricular Assist Devices
    (Wolters Kluwer, 2023) Thohan, Vinay; Abraham, Jacob; Burdorf, Adam; Sulemanjee, Nasir; Jaski, Brian; Guglin, Maya; Pagani, Francis D.; Vidula, Himabindu; Majure, David T.; Napier, Rebecca; Heywood, Thomas J.; Cogswell, Rebecca; Dirckx, Nicholas; Farrar, David J.; Drakos, Stavros G.; INTELLECT 2-HF Investigators; Medicine, School of Medicine
    Background: Hemodynamic-guided management with a pulmonary artery pressure sensor (CardioMEMS) is effective in reducing heart failure hospitalization in patients with chronic heart failure. This study aims to determine the feasibility and clinical utility of the CardioMEMS heart failure system to manage patients supported with left ventricular assist devices (LVADs). Methods: In this multicenter prospective study, we followed patients with HeartMate II (n=52) or HeartMate 3 (n=49) LVADs and with CardioMEMS PA Sensors and measured pulmonary artery pressure, 6-minute walk distance, quality of life (EQ-5D-5 L scores), and heart failure hospitalization rates through 6 months. Patients were stratified as responders (R) and nonresponders to reductions in pulmonary artery diastolic pressure (PAD). Results: There were significant reductions in PAD from baseline to 6 months in R (21.5-16.5 mm Hg; P<0.001), compared with an increase in NR (18.0-20.3; P=0.002), and there was a significant increase in 6-minute walk distance among R (266 versus 322 meters; P=0.025) compared with no change in nonresponder. Patients who maintained PAD <20 compared with PAD ≥20 mm Hg for more than half the time throughout the study (averaging 15.6 versus 23.3 mm Hg) had a statistically significant lower rate of heart failure hospitalization (12.0% versus 38.9%; P=0.005). Conclusions: Patients with LVAD managed with CardioMEMS with a significant reduction in PAD at 6 months showed improvements in 6-minute walk distance. Maintaining PAD <20 mm Hg was associated with fewer heart failure hospitalizations. Hemodynamic-guided management of patients with LVAD with CardioMEMS is feasible and may result in functional and clinical benefits. Prospective evaluation of ambulatory hemodynamic management in patients with LVAD is warranted.