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CaM Kinase IIδ Is Required for Catecholamine-Induced Cardiac Fibrosis but Not Hypertrophy
S22 Journal of Cardiac Failure Vol. 16 No. 8S August 2010 of marker candidates that are differentially detected in the plasma of HF subjects compared to controls that correlate with a panel of HF variables. Further identification and validation of these candidate biomarkers may provide additional insights into the pathophysiology of HF and additional targets for HF therapy.
063 Predictors of Right Ventricular Systolic Dysfunction in Compensated and Decompensated Heart Failure Maya Guglin, Cho Win; Internal Medicine, University of South Florida, Tampa, FL Introduction: Right ventricular (RV) systolic dysfunction is a poor prognostic sign in heart failure (HF). Current understanding of its mechanisms is limited. Objective: We studied parameters associated with RV dysfunction in patients with HF. Methods: We analyzed a limited access dataset from the ESCAPE Trial, provided by the NHLBI. RV systolic function (fractional area change) was measured by echo at the baseline (decompensated HF) and at 3 month follow-up. Univariate anal-
Table 1. Variables Age (yo) LV diameter (mm) LVEF E’ (cm/s) (V max e V min) (ml)
CTRL 34,2 47,9 64 17,8 40
6 6 6 6 6
12 3 2 4 9
GI 42,9 47,6 68 14 35
6 6 6 6 6
10 4 4 3z 9
G II
ANOVA (p)
45,5 6 8 * 52,8 6 7 *x 57 6 7 *x 13,4 * 30 6 9 *
0,009 0,006 0,001 0,009 0,02
Tukey test (p !0,05): * CTL vs.GII p ! 0,05; zCTL vs.G I; x G I vs G II
and minimum volumes (V max e V min), obtained by echocardiography. The maximum diameters of LA and LV, as well as the LV ejection fraction (LVEF) by Mmode were also measured. Results: The comparison of means was made by ANOVA and the Tukey test was used to identify the difference among groups. The variables with statistical difference are shown in the table. p was considered significant when !0.05. Conclusion: patients with CCM and myocardial segmental abnormality of contraction have compromise of LA reservoir function.
Predictors of RV Systolic Dysfunction Covariate RV FAC on Wedge pressure admission PA diastolic pressure PA systolic pressure Right atrial pressure Cardiac output LVEF Mitral deceleration time Velocity of mitral regurgitation A wave velocity Arterial diastolic blood pressure Hematocrit Total bilirubin RV FAC at Wedge pressure, baseline 3 months Wedge pressure, final measurement PA systolic pressure, baseline PA diastolic pressure, baseline PA diastolic pressure, final measurement Right atrial pressure, baseline LVEF, 3 months Deceleration time of mitral inflow, 3 months Mitral regurgitation time velocity integral, 3 months LV outflow tract time velocity integral, 3 months BNP, 1 month Hematocrit, baseline
Bata
P
0.45 !0.0001 0.37 !0.0001 0.35 0.001 0.26 0.013 .21 0.0048 0.22 0.005 0.34 !0.0001 0.27 0.04 0.31 0.001 0.22 0.04 0.2 0.01 0.27 0.001 0.33 0.007 0.36 0.004 0.3 0.013 0.34 0.005 0.42 !0.001 0.3 0.012 0.25 0.004 0.21 0.027 0.48 !0.001 0.35 !0.001 0.35 0.03 0.21 0.012
ysis was performed with linear regression (SPSS 18). Results: Predictors of RV systolic function at baseline and at 3 months are shown in the table. Additionally, alcoholic etiology weakly correlated with the degree of RV dysfunction (r 5 -0.19. p 5 0.009). Velocity of tricuspid regurgitation did not correlate with RV systolic function at any point. Conclusions: Cardiac diastolic pressures and corresponding echo parameters, as well as LVEF and echo parameters of cardiac output predicted RV systolic function in both compensated and decompensated systolic HF. Pulmonary artery diastolic pressure predicted RV dysfunction more consistently than pulmonary artery systolic pressure.
064 Segmental Myocardial Compromise of Left Ventricle and Left Atrial Function in Chagas’ Cardiomyopathy Afonso Y. Matsumoto, Barbara M. Ianni, Edmundo Arteaga-Fernandez, Aloir Q. Araujo, Vera M.C. Salemi, Charles Mady; Cardiomyopathy Unit, Heart Institute (InCor)- HC-FMUSP, Sao Paulo, Brazil Introduction: Segmental myocardial involvement and clinical presentation are variable in Chagas’ cardiomyopathy (CCM). Although the LV function in this disease is well established, the left atrial contribution to the LV diastolic function is not well known. Hypothesis: to test the compromise of LA reservoir function in CCM. Methods: twenty-five patients with diagnosis of CCM were submitted to an echocardiographic study for anatomical and functional (systolic and diastolic) evaluation. The patients were divided in 2 groups: those without (G I, n 5 10) and with (G II, n 5 15) segmental abnormality of contraction of the LV. Twenty two individuals with normal EKG and stress testing and with no contact with the bug that transmits the disease were used as controls (CTL). The characterization of LV diastolic function was made by E and A velocities, E/A ratio, deceleration time of E (DTE) of mitral flow velocity and E’lateral wave obtained by tissue Doppler imaging. The reservoir function of the LA was analysed by the difference between the maximum
065 CaM Kinase IId Is Required for Catecholamine-Induced Cardiac Fibrosis but Not Hypertrophy Michael Grimm, Haiyun Ling, Shikha Mishra, Joan Heller Brown; Department of Pharmacology, University of California, San Diego, La Jolla, CA Chronic sympathetic activation is a well established feature of human heart failure. Catecholamine stimulation causes adaptive and maladaptive events. We used a knock-out mouse model to test the hypothesis that CaMKIId, the most abundant CaMKII isoform in the heart, is required for the onset of pathological features resulting from catecholamine stress. CaMKIId-deficient (KO) and littermate control (WT) mice were infused with 60 mg/kg/d isoproterenol (ISO) or vehicle via osmotic mini pump for two weeks. Both WT and KO mice developed cardiac hypertrophy in response to ISO. However, pathological fibrosis was attenuated in the KO. Acute inotropic responses to ISO were decreased in WT but not KO myocytes isolated from mice after two week ISO treatment, suggesting that CaMKIId could mediate beta-adrenergic desensitization. CaMKII deficiency had no effect on cardiac inotropy and chronotropy following shortterm ISO stimulation of Langendorff-perfused hearts. Basal and ISO-stimulated phosphorylation of the ryanodine receptor at the CaMKII site were decreased in the KO compared to WT. Basal phosphorylation of phospholamban and ryanodine receptor at the CaMKII sites were decreased in the KO. Interestingly, basal phosphorylation of phospholamban at the CaMKII site was decreased in the KO, whereas ISO-stimulated phosphorylation of the same site was not affected, suggesting that maybe another CaMKII isoform or another protein kinase mediates ISO-induced phosphpolamban phosphorylation. We conclude that CaMKIId may contribute to enhanced ryanodine receptor-mediated sarcoplasmic reticulum calcium leak induced by chronic ISO stimulation and thus contributes to pathological changes observed with chronic catecholamine stress.
066 Role of p38/Akt Signaling Pathway in the Regulation of Sodium/Calcium Exchanger Expression in Adult Cardiomyocytes Olga Chernysh, Santhosh K. Mani, Donald R. Menick; Department of Medicine, Division of Cardiology, Medical University of South Carolina, Charleston, SC Introduction: The sodium/calcium exchanger (NCX1) is regulated at the transcriptional level in cardiac hypertrophy and heart failure. Upregulation of NCX1 affects sarcoplasmic reticulum calcium loading and directly contributes to contractile dysfunction of failing myocardium. In animal models, it has been demonstrated that pharmacological inhibition of NCX1 may be beneficial in heart failure and during ischemia/reperfusion. However, most studies have focused only on the acute effects of NCX1 inhibitors on calcium homeostasis, and there is little information available on the potential risks and benefits of chronic therapeutic inhibition of NCX1. Previous work from our laboratory has shown that prolonged treatment with NCX1 inhibitor, KB-R7943 results in the upregulation of Ncx1 gene expression in both isolated adult cardiomyocytes and intact mouse hearts. This upregulation is mediated via the activation of p38 and formation of a NCX1-p38 complex. However, the signaling pathway leading to the increase in Ncx1 gene expression remains to be elucidated. Hypothesis: NCX1, whose activity is acutely sensitive to cytosolic calcium, sodium and membrane potential, can also regulate its own expression in an activity-dependent manner as part of a macromolecular signaling complex. Results: To identify potential downstream targets of p38, we treated isolated adult feline cardiomyocytes with KB-R7943 in the presence of p38 inhibitor, SB203580, which resulted in the inhibition of Akt kinase activation. Co-immunoprecipitation studies also showed that Akt was in complex with NCX1. Conclusion: Our results suggest that p38/Akt pathway plays a role in regulating Ncx1 gene expression in response to pharmacological inhibition of the exchanger.
063 Predictors of Right Ventricular Systolic Dysfunction in Compensated and Decompensated Heart Failure Maya Guglin, Cho Win; Internal Medicine, University of South Florida, Tampa, FL Introduction: Right ventricular (RV) systolic dysfunction is a poor prognostic sign in heart failure (HF). Current understanding of its mechanisms is limited. Objective: We studied parameters associated with RV dysfunction in patients with HF. Methods: We analyzed a limited access dataset from the ESCAPE Trial, provided by the NHLBI. RV systolic function (fractional area change) was measured by echo at the baseline (decompensated HF) and at 3 month follow-up. Univariate anal-
Table 1. Variables Age (yo) LV diameter (mm) LVEF E’ (cm/s) (V max e V min) (ml)
CTRL 34,2 47,9 64 17,8 40
6 6 6 6 6
12 3 2 4 9
GI 42,9 47,6 68 14 35
6 6 6 6 6
10 4 4 3z 9
G II
ANOVA (p)
45,5 6 8 * 52,8 6 7 *x 57 6 7 *x 13,4 * 30 6 9 *
0,009 0,006 0,001 0,009 0,02
Tukey test (p !0,05): * CTL vs.GII p ! 0,05; zCTL vs.G I; x G I vs G II
and minimum volumes (V max e V min), obtained by echocardiography. The maximum diameters of LA and LV, as well as the LV ejection fraction (LVEF) by Mmode were also measured. Results: The comparison of means was made by ANOVA and the Tukey test was used to identify the difference among groups. The variables with statistical difference are shown in the table. p was considered significant when !0.05. Conclusion: patients with CCM and myocardial segmental abnormality of contraction have compromise of LA reservoir function.
Predictors of RV Systolic Dysfunction Covariate RV FAC on Wedge pressure admission PA diastolic pressure PA systolic pressure Right atrial pressure Cardiac output LVEF Mitral deceleration time Velocity of mitral regurgitation A wave velocity Arterial diastolic blood pressure Hematocrit Total bilirubin RV FAC at Wedge pressure, baseline 3 months Wedge pressure, final measurement PA systolic pressure, baseline PA diastolic pressure, baseline PA diastolic pressure, final measurement Right atrial pressure, baseline LVEF, 3 months Deceleration time of mitral inflow, 3 months Mitral regurgitation time velocity integral, 3 months LV outflow tract time velocity integral, 3 months BNP, 1 month Hematocrit, baseline
Bata
P
0.45 !0.0001 0.37 !0.0001 0.35 0.001 0.26 0.013 .21 0.0048 0.22 0.005 0.34 !0.0001 0.27 0.04 0.31 0.001 0.22 0.04 0.2 0.01 0.27 0.001 0.33 0.007 0.36 0.004 0.3 0.013 0.34 0.005 0.42 !0.001 0.3 0.012 0.25 0.004 0.21 0.027 0.48 !0.001 0.35 !0.001 0.35 0.03 0.21 0.012
ysis was performed with linear regression (SPSS 18). Results: Predictors of RV systolic function at baseline and at 3 months are shown in the table. Additionally, alcoholic etiology weakly correlated with the degree of RV dysfunction (r 5 -0.19. p 5 0.009). Velocity of tricuspid regurgitation did not correlate with RV systolic function at any point. Conclusions: Cardiac diastolic pressures and corresponding echo parameters, as well as LVEF and echo parameters of cardiac output predicted RV systolic function in both compensated and decompensated systolic HF. Pulmonary artery diastolic pressure predicted RV dysfunction more consistently than pulmonary artery systolic pressure.
064 Segmental Myocardial Compromise of Left Ventricle and Left Atrial Function in Chagas’ Cardiomyopathy Afonso Y. Matsumoto, Barbara M. Ianni, Edmundo Arteaga-Fernandez, Aloir Q. Araujo, Vera M.C. Salemi, Charles Mady; Cardiomyopathy Unit, Heart Institute (InCor)- HC-FMUSP, Sao Paulo, Brazil Introduction: Segmental myocardial involvement and clinical presentation are variable in Chagas’ cardiomyopathy (CCM). Although the LV function in this disease is well established, the left atrial contribution to the LV diastolic function is not well known. Hypothesis: to test the compromise of LA reservoir function in CCM. Methods: twenty-five patients with diagnosis of CCM were submitted to an echocardiographic study for anatomical and functional (systolic and diastolic) evaluation. The patients were divided in 2 groups: those without (G I, n 5 10) and with (G II, n 5 15) segmental abnormality of contraction of the LV. Twenty two individuals with normal EKG and stress testing and with no contact with the bug that transmits the disease were used as controls (CTL). The characterization of LV diastolic function was made by E and A velocities, E/A ratio, deceleration time of E (DTE) of mitral flow velocity and E’lateral wave obtained by tissue Doppler imaging. The reservoir function of the LA was analysed by the difference between the maximum
065 CaM Kinase IId Is Required for Catecholamine-Induced Cardiac Fibrosis but Not Hypertrophy Michael Grimm, Haiyun Ling, Shikha Mishra, Joan Heller Brown; Department of Pharmacology, University of California, San Diego, La Jolla, CA Chronic sympathetic activation is a well established feature of human heart failure. Catecholamine stimulation causes adaptive and maladaptive events. We used a knock-out mouse model to test the hypothesis that CaMKIId, the most abundant CaMKII isoform in the heart, is required for the onset of pathological features resulting from catecholamine stress. CaMKIId-deficient (KO) and littermate control (WT) mice were infused with 60 mg/kg/d isoproterenol (ISO) or vehicle via osmotic mini pump for two weeks. Both WT and KO mice developed cardiac hypertrophy in response to ISO. However, pathological fibrosis was attenuated in the KO. Acute inotropic responses to ISO were decreased in WT but not KO myocytes isolated from mice after two week ISO treatment, suggesting that CaMKIId could mediate beta-adrenergic desensitization. CaMKII deficiency had no effect on cardiac inotropy and chronotropy following shortterm ISO stimulation of Langendorff-perfused hearts. Basal and ISO-stimulated phosphorylation of the ryanodine receptor at the CaMKII site were decreased in the KO compared to WT. Basal phosphorylation of phospholamban and ryanodine receptor at the CaMKII sites were decreased in the KO. Interestingly, basal phosphorylation of phospholamban at the CaMKII site was decreased in the KO, whereas ISO-stimulated phosphorylation of the same site was not affected, suggesting that maybe another CaMKII isoform or another protein kinase mediates ISO-induced phosphpolamban phosphorylation. We conclude that CaMKIId may contribute to enhanced ryanodine receptor-mediated sarcoplasmic reticulum calcium leak induced by chronic ISO stimulation and thus contributes to pathological changes observed with chronic catecholamine stress.
066 Role of p38/Akt Signaling Pathway in the Regulation of Sodium/Calcium Exchanger Expression in Adult Cardiomyocytes Olga Chernysh, Santhosh K. Mani, Donald R. Menick; Department of Medicine, Division of Cardiology, Medical University of South Carolina, Charleston, SC Introduction: The sodium/calcium exchanger (NCX1) is regulated at the transcriptional level in cardiac hypertrophy and heart failure. Upregulation of NCX1 affects sarcoplasmic reticulum calcium loading and directly contributes to contractile dysfunction of failing myocardium. In animal models, it has been demonstrated that pharmacological inhibition of NCX1 may be beneficial in heart failure and during ischemia/reperfusion. However, most studies have focused only on the acute effects of NCX1 inhibitors on calcium homeostasis, and there is little information available on the potential risks and benefits of chronic therapeutic inhibition of NCX1. Previous work from our laboratory has shown that prolonged treatment with NCX1 inhibitor, KB-R7943 results in the upregulation of Ncx1 gene expression in both isolated adult cardiomyocytes and intact mouse hearts. This upregulation is mediated via the activation of p38 and formation of a NCX1-p38 complex. However, the signaling pathway leading to the increase in Ncx1 gene expression remains to be elucidated. Hypothesis: NCX1, whose activity is acutely sensitive to cytosolic calcium, sodium and membrane potential, can also regulate its own expression in an activity-dependent manner as part of a macromolecular signaling complex. Results: To identify potential downstream targets of p38, we treated isolated adult feline cardiomyocytes with KB-R7943 in the presence of p38 inhibitor, SB203580, which resulted in the inhibition of Akt kinase activation. Co-immunoprecipitation studies also showed that Akt was in complex with NCX1. Conclusion: Our results suggest that p38/Akt pathway plays a role in regulating Ncx1 gene expression in response to pharmacological inhibition of the exchanger.