Abstract 17904: Deficiency of Yes-associated Protein Promotes Cardiac Dysfunction in Response to Pressure Overload in the Mouse Heart

Circulation ◽  
2015 ◽  
Vol 132 (suppl_3) ◽  
Author(s):  
Jaemin Byun ◽  
Dominic P Del Re ◽  
Peiyong Zhai ◽  
Akihiro Shirakabe ◽  
Junichi Sadoshima
Keyword(s):  
Cardiac Hypertrophy ◽  
Mammalian Cells ◽  
Diastolic Pressure ◽  
Systolic Function ◽  
Pressure Overload ◽  
Wall Stress ◽  
Left Ventricular ◽  
Lv Function ◽  
Mouse Heart ◽  
And Control

Yes-Associated Protein (YAP), a downstream effector of the Hippo pathway, plays an important role in regulating cell proliferation and survival in mammalian cells. We have shown that cardiac-specific loss of YAP leads to increased cardiomyocyte (CM) apoptosis and impaired hypertrophy during chronic myocardial infarction in the mouse heart. However, it remains unclear whether YAP mediates hypertrophy of individual CMs under stress conditions in vivo. We hypothesized that endogenous YAP plays an essential role in mediating hypertrophy and survival of CMs in response to pressure overload (PO). Three-month-old YAP+/fl;α-MHC-Cre (YAP-cKO) and YAP+/fl (control) mice were subjected to transverse aortic constriction (TAC). Two weeks later, YAP-cKO and control mice developed similar levels of cardiac hypertrophy (left ventricular (LV) weight/tibia length: 7.27±0.38, 6.93±0.29) compared to sham (5.08±0.14, 4.07±0.33). LV CM cross sectional area was similarly increased by TAC in YAP-cKO and control mice compared to their respective shams. Induction of fetal-type genes, such as Anf and Myh7, was also similar in YAP-cKO and control mice. YAP-cKO and control mice exhibited similar baseline LV systolic function (ejection fraction (EF): 75, 76%). YAP-cKO mice had significantly decreased LV function after TAC compared to Sham-control mice (EF: 51%, 76%, p<0.05) and TAC-control mice (75%, p<0.05). LV end diastolic pressure (LVEDP, mmHg) was significantly increased (19.3 ±3.2, 9.8±1.6, p<0.05), and LV +dP/dt (mmHg/s, 7250±588, 9500±453, p<0.01) and -dP/dt (mmHg/s, 6000±433, 7781± 314, p<0.05) were significantly decreased in YAP-cKO compared to in control mice after TAC. LV end diastolic diameter (mm) was significantly greater in YAP-cKO than in control mice after TAC (3.95±0.11, 3.35±0.15, p<0.05), whereas LV pressure was similar, suggesting that LV wall stress was elevated in YAP-cKO compared to in control mice. Since cardiac hypertrophy in YAP-cKO mice is similar to that in control mice despite elevated wall stress, the lack of YAP appears to limit the extent of cardiac hypertrophy in response to increased wall stress. These data suggest that endogenous YAP plays an important role in mediating adaptive hypertrophy and protecting the heart against PO.

Heart size-independent analysis of myocardial function in murine pressure overload hypertrophy

2002 ◽  
Vol 282 (6) ◽  
pp. H2190-H2197 ◽  
Author(s):  
Hideyuki Takaoka ◽  
Giovanni Esposito ◽  
Lan Mao ◽  
Hiroyuki Suga ◽  
Howard A. Rockman
Keyword(s):  
Cardiac Hypertrophy ◽  
Pressure Overload ◽  
Wall Stress ◽  
Left Ventricular ◽  
Lv Function ◽  
Compensatory Mechanism ◽  
Compensatory Response ◽  
Myocardial Stiffness ◽  
Stiffness Constant

Pressure overload cardiac hypertrophy may be a compensatory mechanism to normalize systolic wall stress and preserve left ventricular (LV) function. To test this concept, we developed a novel in vivo method to measure myocardial stress (ς)-strain (ɛ) relations in normal and hypertrophied mice. LV volume was measured using two pairs of miniature omnidirectional piezoelectric crystals implanted orthogonally in the endocardium and one crystal placed on the anterior free wall to measure instantaneous wall thickness. Highly linear ς-ε relations were obtained in control ( n = 7) and hypertrophied mice produced by 7 days of transverse aortic constriction (TAC; n = 13). Administration of dobutamine in control mice significantly increased the load-independent measure of LV contractility, systolic myocardial stiffness. In TAC mice, systolic myocardial stiffness was significantly greater than in control mice (3,156 ± 1,433 vs. 1,435 ± 467 g/cm2, P < 0.01), indicating enhanced myocardial contractility with pressure overload. However, despite the increased systolic performance, both active (time constant of LV pressure decay) and passive (diastolic myocardial stiffness constant) diastolic properties were markedly abnormal in TAC mice compared with control mice. These data suggest that the development of cardiac hypertrophy is associated with a heightened contractile state, perhaps as an early compensatory response to pressure overload.

Pressure overload-induced hypertrophy in transgenic mice selectively overexpressing AT2 receptors in ventricular myocytes

2008 ◽  
Vol 294 (3) ◽  
pp. H1274-H1281 ◽  
Author(s):  
Xinhua Yan ◽  
Adam J. T. Schuldt ◽  
Robert L. Price ◽  
Ivo Amende ◽  
Fen-Fen Liu ◽  
...  
Keyword(s):  
Transgenic Mice ◽  
Cardiac Hypertrophy ◽  
Ventricular Myocytes ◽  
Diastolic Pressure ◽  
Tyrosine Phosphatase ◽  
Systolic Pressure ◽  
Pressure Overload ◽  
Left Ventricular ◽  
Lv Function ◽  
Aortic Banding

The role of the angiotensin II type 2 (AT2) receptor in cardiac hypertrophy remains controversial. We studied the effects of AT2 receptors on chronic pressure overload-induced cardiac hypertrophy in transgenic mice selectively overexpressing AT2 receptors in ventricular myocytes. Left ventricular (LV) hypertrophy was induced by ascending aorta banding (AS). Transgenic mice overexpressing AT2 (AT2TG-AS) and nontransgenic mice (NTG-AS) were studied after 70 days of aortic banding. Nonbanded NTG mice were used as controls. LV function was determined by catheterization via LV puncture and cardiac magnetic resonance imaging. LV myocyte diameter and interstitial collagen were determined by confocal microscopy. Atrial natriuretic polypeptide (ANP) and brain natriuretic peptide (BNP) were analyzed by Northern blot. Sarco(endo)plasmic reticulum Ca2+-ATPase (SERCA)2, inducible nitric oxide synthase (iNOS), endothelial NOS, ERK1/2, p70S6K, Src-homology 2 domain-containing protein tyrosine phosphatase-1, and protein serine/threonine phosphatase 2A were analyzed by Western blot. LV myocyte diameter and collagen were significantly reduced in AT2TG-AS compared with NTG-AS mice. LV anterior and posterior wall thickness were not different between AT2TG-AS and NTG-AS mice. LV systolic and diastolic dimensions were significantly higher in AT2TG-AS than in NTG-AS mice. LV systolic pressure and end-diastolic pressure were lower in AT2TG-AS than in NTG-AS mice. ANP, BNP, and SERCA2 were not different between AT2TG-AS and NTG-AS mice. Phospholamban (PLB) and the PLB-to-SERCA2 ratio were significantly higher in AT2TG-AS than in NTG-AS mice. iNOS was higher in AT2TG-AS than in NTG-AS mice but not significantly different. Our results indicate that AT2 receptor overexpression modified the pathological hypertrophic response to aortic banding in transgenic mice.

Effects of avertin versus xylazine-ketamine anesthesia on cardiac function in normal mice

2001 ◽  
Vol 281 (5) ◽  
pp. H1938-H1945 ◽  
Author(s):  
Chari Y. T. Hart ◽  
John C. Burnett ◽  
Margaret M. Redfield
Keyword(s):  
Cardiac Function ◽  
Diastolic Pressure ◽  
Systolic Function ◽  
Pressure Rise ◽  
Left Ventricular ◽  
Lv Function ◽  
Ketamine Anesthesia ◽  
The Difference ◽  
And Function ◽  
Derivatives Of

Anesthetic regimens commonly administered during studies that assess cardiac structure and function in mice are xylazine-ketamine (XK) and avertin (AV). While it is known that XK anesthesia produces more bradycardia in the mouse, the effects of XK and AV on cardiac function have not been compared. We anesthetized normal adult male Swiss Webster mice with XK or AV. Transthoracic echocardiography and closed-chest cardiac catheterization were performed to assess heart rate (HR), left ventricular (LV) dimensions at end diastole and end systole (LVDd and LVDs, respectively), fractional shortening (FS), LV end-diastolic pressure (LVEDP), the time constant of isovolumic relaxation (τ), and the first derivatives of LV pressure rise and fall (dP/d t max and dP/d t min, respectively). During echocardiography, HR was lower in XK than AV mice (250 ± 14 beats/min in XK vs. 453 ± 24 beats/min in AV, P < 0.05). Preload was increased in XK mice (LVDd: 4.1 ± 0.08 mm in XK vs. 3.8 ± 0.09 mm in AV, P < 0.05). FS, a load-dependent index of systolic function, was increased in XK mice (45 ± 1.2% in XK vs. 40 ± 0.8% in AV, P < 0.05). At LV catheterization, the difference in HR with AV (453 ± 24 beats/min) and XK (342 ± 30 beats/min, P < 0.05) anesthesia was more variable, and no significant differences in systolic or diastolic function were seen in the group as a whole. However, in XK mice with HR <300 beats/min, LVEDP was increased (28 ± 5 vs. 6.2 ± 2 mmHg in mice with HR >300 beats/min, P < 0.05), whereas systolic (LV dP/d t max: 4,402 ± 798 vs. 8,250 ± 415 mmHg/s in mice with HR >300 beats/min, P < 0.05) and diastolic (τ: 23 ± 2 vs. 14 ± 1 ms in mice with HR >300 beats/min, P < 0.05) function were impaired. Compared with AV, XK produces profound bradycardia with effects on loading conditions and ventricular function. The disparate findings at echocardiography and LV catheterization underscore the importance of comprehensive assessment of LV function in the mouse.

Abstract 14952: Hemodynamic Comparison of Left Ventricular Function in Pressure Overload- versus Volume Overload-Induced Heart Failure Models by Invasive Pressure-Volume Analysis

Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Mihály Ruppert ◽  
Christian Karime ◽  
Alex A Sayour ◽  
Attila Oláh ◽  
Dávid Nagy ◽  
...  
Keyword(s):  
Heart Failure ◽  
Systolic Function ◽  
Pressure Overload ◽  
Volume Overload ◽  
Detailed Comparison ◽  
Left Ventricular ◽  
Lv Function ◽  
Arterial Elastance ◽  
Lv Remodeling ◽  
Av Shunt

Introduction: Both sustained left ventricular (LV) pressure overload (PO) and volume overload (VO) induces LV remodeling and eventually development of heart failure (HF). Using rat models, the present study aimed to provide a detailed comparison of distinct aspects of LV function in PO- and VO-induced HF. Methods: PO and VO was induced by transverse aortic constriction (TAC, n=12) and aortocaval shunt (AV-shunt, n=12) creation respectively. Controls underwent corresponding sham operations (n=11). LV remodeling was characterized by echocardiography, histology, qRT PCR, and western blot. LV function was assessed by invasive pressure-volume (P-V) analysis. Results: Both sustained PO and VO resulted in the development of HF, as evidenced by increased LV BNP mRNA expression, pulmonary edema, and characteristic symptoms. While the extent of LV hypertrophy was comparable between the HF models, PO induced concentric while VO evoked eccentric LV remodeling. P-V analysis revealed impaired systolic function in both HF models. Accordingly, decreased ejection fraction and impaired ventriculo-arterial coupling (calculated as the ratio of arterial elastance/LV contractility [VAC]: 0.38±0.05 vs. 1.30±0.13, ShamTAC vs. TAC and 0.52±0.08 vs. 1.17±0.13, ShamAV-Shunt vs. AV-shunt; p<0.05) was detected in both HF models. However, in case of VO the severely reduced LV contractility (slope of end-systolic P-V relationship: 1.79±0.19 vs. 0.52±0.06, ShamAV-Shunt vs. AV-shunt, p<0.05 and 2.14±0.28 vs. 2.03±0.21, ShamTAC vs. TAC p>0.05) underpinned the contractility-afterload mismatch, while in case of PO the increased afterload (arterial elastance: 0.77±0.07 vs. 2.64±0.28, ShamTAC vs. TAC and 0.80±0.07 vs. 0.54±0.05, ShamAV-Shunt vs. AV-shunt; p<0.05) was the main determinant. Furthermore, prolongation of active relaxation occurred to a greater extent in case of PO. In addition, increased myocardial stiffness was only observed in PO-induced HF. Conclusion: Systolic function was reduced in both HF models. However, different factors underpinned the impaired VAC in case of VO (reduced LV contractility) and PO (increased arterial elastance). Furthermore, although diastolic function deteriorated in both models, it occurred to a greater extent in case of PO.

Colchicine attenuates left ventricular hypertrophy but preserves cardiac function of aortic-constricted rats

2003 ◽  
Vol 94 (4) ◽  
pp. 1627-1633 ◽  
Author(s):  
Beatriz S. Scopacasa ◽  
Vicente P. A. Teixeira ◽  
Kleber G. Franchini
Keyword(s):  
Diastolic Pressure ◽  
Systolic Pressure ◽  
Pressure Overload ◽  
Colchicine Treatment ◽  
Average Diameter ◽  
Left Ventricular ◽  
Lv Function ◽  
Right Ventricular Mass ◽  
Lv Mass ◽  
Phenylephrine Infusion

To investigate the effects of colchicine on left ventricular (LV) function and hypertrophy (LVH) of rats subjected to constriction of transverse aorta (TAoC), we evaluated SO (sham operated, vehicle; n = 25), SO-T (sham operated, colchicine 0.4 mg/kg body wt ip daily; n = 38), TAoC (vehicle; n = 37), and TAoC-T (TAoC, colchicine; n = 34) on the 2nd, 6th, and 15th day after surgery. Colchicine attenuated LVH of TAoC-T compared with TAoC rats, as evaluated by ratio between LV mass (LVM) and right ventricular mass, LV wall thickness, and average diameter of cardiac myocytes. Systolic gradient across TAoC (∼45 mmHg), LV systolic pressure, LV end-diastolic pressure, and rate of LV pressure increase (+dP/d t) were comparable in TAoC-T and TAoC rats. However, the baseline and increases of LV systolic pressure-to-LVM and +dP/d t-to-LVMratios induced by phenylephrine infusion were greater in TAoC-T and SO-T compared with SO rats. Baseline and increases of +dP/d t-to-LVM ratio were reduced in TAoC compared with SO rats. TAoC rats increased polymerized fraction of tubulin compared with SO, SO-T, and TAoC-T rats. Our results indicate that colchicine treatment reduced LVH to pressure overload but preserved LV function.

Diverse regulation of IP3 and ryanodine receptors by pentazocine through σ1-receptor in cardiomyocytes

2013 ◽  
Vol 305 (8) ◽  
pp. H1201-H1212 ◽  
Author(s):  
Hideaki Tagashira ◽  
Md. Shenuarin Bhuiyan ◽  
Kohji Fukunaga
Keyword(s):  
Cardiac Hypertrophy ◽  
Diastolic Pressure ◽  
Ryanodine Receptors ◽  
Pressure Overload ◽  
Left Ventricular ◽  
Female Rats ◽  
In Vivo Studies ◽  
Atp Production ◽  
Cultured Cardiomyocytes

Although pentazocine binds to σ1-receptor (σ1R) with high affinity, the physiological relevance of its binding remains unclear. We first confirmed that σ1R stimulation with pentazocine rescues contractile dysfunction following pressure overload (PO)-induced cardiac hypertrophy ovariectomized (OVX) female rats. In in vivo studies, vehicle, pentazocine (0.5–1.0 mg/kg ip), and NE-100 (1.0 mg/kg po), a σ1R antagonist, were administered for 4 wk (once daily) starting from the onset of aortic banding after OVX. We also examined antihypertrophic effects of pentazocine (0.5–1 μM) in cultured cardiomyocytes exposed to angiotensin II. Pentazocine administration significantly inhibited PO-induced cardiac hypertrophy and rescued hypertrophy-induced impairment of cardiac dysfunctions such as left ventricular end-diastolic pressure, left ventricular developed pressure, and left ventricular contraction and relaxation (±dp/dt) rates. Coadministration of NE-100 with pentazocine eliminated pentazocine-induced amelioration of heart dysfunction. Interestingly, pentazocine administration inhibited PO-induced σ1R reduction and inositol-1,4,5-trisphosphate (IP3) receptor type 2 (IP3R2) upregulation in heart. Therefore, the reduced mitochondrial ATP production following PO was restored by pentazocine administration. Furthermore, we found that σ1R binds to the ryanodine receptor (RyR) in addition to IP3 receptor (IP3R) in cardiomyocytes. The σ1R/RyR complexes were decreased following OVX-PO and restored by pentazocine administration. We noticed that pentazocine inhibits the ryanodine-induced Ca2+ release from sarcoplasmic reticulum (SR) in cultured cardiomyocytes. Taken together, the stimulation of σ1R by pentazocine rescues cardiac dysfunction by restoring IP3R-mediated mitochondrial ATP production and by suppressing RyR-mediated Ca2+ leak from SR in cardiomyocytes.

scholarly journals Rats are protected from the stress of chronic pressure overload compared with mice

2020 ◽  
Vol 318 (5) ◽  
pp. R894-R900 ◽  
Author(s):  
Koichi Nishimura ◽  
Marko Oydanich ◽  
Jie Zhang ◽  
Denis Babici ◽  
Diego Fraidenraich ◽  
...  
Keyword(s):  
Troponin I ◽  
Diastolic Pressure ◽  
Pressure Overload ◽  
Wall Stress ◽  
Left Ventricular ◽  
Pressure Gradients ◽  
Sprague Dawley ◽  
Sprague Dawley Rats ◽  
Systolic And Diastolic Function ◽  
Systolic Wall Stress

The goal of this investigation was to compare the effects of chronic (4 wk) transverse aortic constriction (TAC) in Sprague-Dawley rats and C57BL/6J mice. TAC, after 1 day, induced similar left ventricular (LV) pressure gradients in both rats ( n = 7) and mice ( n = 7) (113 ± 5.4 vs. 103 ± 11.5 mmHg), and after 4 wk, the percent increase in LV hypertrophy, as reflected by LV/tibial length (51% vs 49%), was similar in rats ( n = 12) and mice ( n = 12). After 4 wk of TAC, LV systolic and diastolic function were preserved in TAC rats. In contrast, in TAC mice, LV ejection fraction decreased by 31% compared with sham, along with increases in LV end-diastolic pressure (153%) and LV systolic wall stress (86%). Angiogenesis, as reflected by Ki67 staining of capillaries, increased more in rats ( n = 6) than in mice ( n = 6; 10 ± 2 vs. 6 ± 1 Ki67-positive cells/field). Myocardial blood flow fell by 55% and coronary reserve by 28% in mice with TAC ( n = 4), but they were preserved in rats ( n = 4). Myogenesis, as reflected by c-kit-positive myocytes staining positively for troponin I, is another mechanism that can confer protection after TAC. However, the c-kit-positive cells in rats with TAC were all negative for troponin I, indicating the absence of myogenesis. Thus, rats showed relative tolerance to severe pressure overload compared with mice, with mechanisms involving angiogenesis but not myogenesis.

scholarly journals Orai1 Channel Inhibition Preserves Left Ventricular Systolic Function and Normal Ca 2+ Handling After Pressure Overload

Circulation ◽  
2020 ◽  
Vol 141 (3) ◽  
pp. 199-216 ◽  
Author(s):  
Fiona Bartoli ◽  
Marc A. Bailey ◽  
Baptiste Rode ◽  
Philippe Mateo ◽  
Fabrice Antigny ◽  
...  
Keyword(s):  
Cardiac Hypertrophy ◽  
Systolic Function ◽  
Systolic Dysfunction ◽  
Pressure Overload ◽  
Left Ventricular Systolic Function ◽  
Left Ventricular ◽  
Specific Expression ◽  
Channel Inhibition

Background: Orai1 is a critical ion channel subunit, best recognized as a mediator of store-operated Ca 2+ entry (SOCE) in nonexcitable cells. SOCE has recently emerged as a key contributor of cardiac hypertrophy and heart failure but the relevance of Orai1 is still unclear. Methods: To test the role of these Orai1 channels in the cardiac pathophysiology, a transgenic mouse was generated with cardiomyocyte-specific expression of an ion pore-disruptive Orai1 R91W mutant (C-dnO1). Synthetic chemistry and channel screening strategies were used to develop 4-(2,5-dimethoxyphenyl)-N-[(pyridin-4-yl)methyl]aniline (hereafter referred to as JPIII), a small-molecule Orai1 channel inhibitor suitable for in vivo delivery. Results: Adult mice subjected to transverse aortic constriction (TAC) developed cardiac hypertrophy and reduced ventricular function associated with increased Orai1 expression and Orai1-dependent SOCE (assessed by Mn 2+ influx). C-dnO1 mice displayed normal cardiac electromechanical function and cellular excitation-contraction coupling despite reduced Orai1-dependent SOCE. Five weeks after TAC, C-dnO1 mice were protected from systolic dysfunction (assessed by preserved left ventricular fractional shortening and ejection fraction) even if increased cardiac mass and prohypertrophic markers induction were observed. This is correlated with a protection from TAC-induced cellular Ca 2+ signaling alterations (increased SOCE, decreased [Ca 2+ ] i transients amplitude and decay rate, lower SR Ca 2+ load and depressed cellular contractility) and SERCA2a downregulation in ventricular cardiomyocytes from C-dnO1 mice, associated with blunted Pyk2 signaling. There was also less fibrosis in heart sections from C-dnO1 mice after TAC. Moreover, 3 weeks treatment with JPIII following 5 weeks of TAC confirmed the translational relevance of an Orai1 inhibition strategy during hypertrophic insult. Conclusions: The findings suggest a key role of cardiac Orai1 channels and the potential for Orai1 channel inhibitors as inotropic therapies for maintaining contractility reserve after hypertrophic stress.

scholarly journals Performance indicators of left ventricular strain, wall stress and serum brain natriuretic peptide levels in chronic hemodialysis patients

2021 ◽  
pp. 22-39
Author(s):  
Abeer M. SHAWKY ◽  
Rehab M. HAMDY ◽  
Asmaa A. ELMADBOULY
Keyword(s):  
Brain Natriuretic Peptide ◽  
Natriuretic Peptide ◽  
Systolic Function ◽  
Global Longitudinal Strain ◽  
Wall Stress ◽  
Serum Levels ◽  
Left Ventricular ◽  
Chronic Hemodialysis ◽  
Lv Function ◽  
Endstage Renal Disease

Background: Left ventricular (LV) global longitudinal strain (GLS) is a reliable determinant of LV systolic function. The precise relationship between LV wall stress and serum brain natriuretic peptide (BNP) concentrations in hemodialysis (HD) patients require clariϐication. BNP levels are raised in patients with endstage renal disease (ESRD) and could reflect LV impairment amongst HD patients. Objective: This study sought to evaluate the clinical utility of LV–GLS, wall stress and serum BNP levels in chronic HD patients. The correlations between BNP levels with both LV wall stress and LV–GLS were assessed. Methodology: A total of 30 ESRD patients on regular HD – divided into 15 patients with LV ejection fraction (EF) <50% and 15 patients with LV EF > 50% – and 15 agematched healthy subjects were assessed. LV function and structure were measured using conventional echocardiography, including LV meridional wall stress (LVMWS), LV mass index (LVM I) and two-dimensional speckle tracking echocardiography for determination of LV–GLS. Serum BNP levels were evaluated after HD sessions. Results: There were significant increases in LVM SW (189.2 ± 81 vs. 72.2 ± 20.6 dynes/cm 2 2 1000, P < 0.0001), higher levels of BNP (1238 ± 1085.5 vs. 71 ± 23.4 pg/ml, P<0.0001), w hilst LV–GLS was signiϐicantly reduced (15.1 ± 3.1 vs. 20.8 ± 1.7%, P <0.0001) in HD patients, when compared to the controls. Higher values of LVMWS (246.9 ± 67.5 vs. 131.5 ± 43.6 dynes/cm 2 2 1000, P <0.0001) and BNP (1925.4 ± 1087 vs. 550.5 ± 496.5pg/ml, P < 0.0005) with further impairment of LV–GLS (13.8 ± 2.5 vs. 16.4 ± 5.4%, P < 0.05) were found in patients with LV EF 0 50% than those with LV EF > 50%. Serum levels of BNP were positively correlated with LVM I (r = 0.896, P < 0.0001) and LVMW S (r = 0.697, P < 0.0001), but negatively correlated with LV–GLS (r = 0 0.587, P < 0.0001). Conclusion: LV–GLS and LVMWS are useful imaging markers for detection of LV dysfunction in HD patients. Serum BNP level is influenced by LV structural abnormalities, being regarded as a crucial hemodynamic biomarker in those patients.

Abstract 18122: Mir-206 Plays an Important Role in Mediating Pressure Overload-induced Cardiac Hypertrophy

Circulation ◽  
2015 ◽  
Vol 132 (suppl_3) ◽  
Author(s):  
Sebstiano Sciarretta ◽  
Yanfei Yang ◽  
Dominic P Del Re ◽  
Junichi Sadoshima
Keyword(s):  
Cardiac Hypertrophy ◽  
Sequence Similarity ◽  
Pressure Overload ◽  
Left Ventricular ◽  
Pcr Analysis ◽  
Mouse Heart ◽  
Sham Operation ◽  
Hippo Signaling ◽  
Qrt Pcr

Introduction: Expression of miR-206 is upregulated by YAP, a key transcription co-factor controlled by the Hippo signaling pathway, and mediates YAP-induced hypertrophy and survival of cardiomyocytes. Although miR-206 is known to promote hypertrophy of skeletal muscle, the role of miR-206 in the heart under clinically relevant conditions in vivo remains unknown. We investigated the role of miR-206 in mediating cardiac hypertrophy in response to pressure overload (PO). Results: The level of miR-206 in the mouse heart, as evaluated by qRT-PCR, was upregulated 2.9 fold (p<0.05) 7 days after transverse aortic constriction (TAC) compared to sham operation. In order to evaluate the involvement of miR-206 in cardiac hypertrophy, wild-type C57B/6J mice were administered LNA inhibitor designed to selectively inhibit miR-206, or control scrambled LNA, by tail vein injection. Specificity of the LNA inhibitor was confirmed by qRT-PCR analysis of miRNA expression 48 hours after treatment. Notably, the LNA inhibitor did not affect the level of miR-1, which has a sequence similarity with miR-206. After 48 hours, mice from both treatment groups were subjected to sham operation or TAC. After 7 days of TAC, echocardiography was performed and mice were sacrificed. Upregulation of myocardial miR-206 expression levels after 7 days TAC observed in LNA control-treated mice was completely abolished in LNA-anti-206 -treated mice. A significant increase in left ventricular weight/tibial length (mg/mm) in LNA control-treated mice following TAC was observed (sham vs TAC: 3.7, 4.8, p<0.05); however, no increase was observed in LNA-anti-206 -treated mice (3.8, 3.8). We also noted significant differences in chamber wall thickness (mm) between the LNA-control and LNA-anti-206-treated TAC groups (diastolic posterior wall 0.91, 0.61, p<0.05). Additionally, cardiomyocyte cross sectional area (1.23, 0.9, p<0.05) and ANF expression (2.5, 1.3, P<0.05) were significantly increased in the LNA control-treated TAC group, and these responses were attenuated in the LNA-anti-206-treated mice. Conclusions: These data demonstrate that inhibition of miR-206 impairs PO-induced hypertrophy and indicates that miR-206 is an important endogenous mediator of heart growth in response to PO.

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