Abstract P425: Sirtuin 3 Attenuates Doxorubicin Induced Cardiac Dysfunction By Regulating The Mitochondrial Acetylome And Alterations Of The Cardiac Lipidome

2021 ◽  
Vol 129 (Suppl_1) ◽  
Author(s):  
Mateusz M Tomczyk ◽  
Arun Surendran ◽  
Bo Xiang ◽  
Prasoon Agarwal ◽  
Kyle G Cheung ◽  
...  

Doxorubicin (DOX) is a chemotherapeutic with dose-dependent cardiotoxic effects that limits its use in patients. Previously we showed that DOX decreases expression of the mitochondrial lysine deacetylase SIRT3 in the mouse heart. We hypothesize that DOX impairs cardiac function and energy production through reduced SIRT3 and altered mitochondrial acetylation. We further hypothesize that increased SIRT3 expression could attenuate DOX-induced cardiac dysfunction via alterations of protein acetylation to enzymes involved in lipid remodeling and metabolic processes. Mice expressing cardiac restricted full length M1-SIRT3 (mitochondrial localized), and short M3-SIRT3 (lacking localization signal) received saline or DOX injections of 8 mg/kg body weight for 4 weeks and compared to non-transgenic (Non-Tg) littermates. Transthoracic echocardiography was performed on all mice (n=10). Total cardiac lipids were isolated from DOX treated cardiac tissue by chloroform:methanol extraction and global lipid analysis was performed by QTRAP LC-MS/MS (n=6). Cardiac mitochondria were and an anti-acetylated lysine antibody was used to enrich for tryptic digested peptides containing Acetyl-K and analyzed by QTRAP LC-MS/MS (n=6). In non-Tg mice, DOX caused cardiac dysfunction and expression of M1-SIRT3 and M3-SIRT3 transgenes in the heart preserved left ventricular posterior wall thickness (P<0.05) and ejection fraction (P<0.05) in DOX treated mice. Triglycerides and phospholipids (PE, PI, PC) were decreased in DOX treated mouse hearts while phosphatidylserine (PS), sphingomyelin and ganglioside (GM3) lipid species were increased (p<0.05). A negative correlation between decreased cardiac output and increased GM3 24:1 (R=-0.62, P<0.05), PS 38:4 levels (R=-0.81, P<0.005) and SM 35:1 (R=-0.65, P<0.05) was identified. 36 acetylated peptides involved in metabolic processes, oxidative stress resistance and lipid remodeling (eg. IDH2, SOD2, HADHA, P<0.05) were significantly altered in DOX-treated mice. Increased SIRT3 expression in the heart rescues DOX-induced cardiac dysfunction. DOX-induced cardiac dysfunction involved alterations in cardiac lipids and acetylated proteins that could be rescued by increased SIRT3 expression in the heart.

2009 ◽  
Vol 297 (1) ◽  
pp. H153-H162 ◽  
Author(s):  
Sabrina Serpillon ◽  
Beverly C. Floyd ◽  
Rakhee S. Gupte ◽  
Shimran George ◽  
Mark Kozicky ◽  
...  

Increased oxidative stress is a known cause of cardiac dysfunction in animals and patients with diabetes, but the sources of reactive oxygen species [e.g., superoxide anion (O2−)] and the mechanisms underlying O2− production in diabetic hearts are not clearly understood. Our aim was to determine whether NADPH oxidase (Nox) is a source of O2− and whether glucose-6-phosphate dehydrogenase (G6PD)-derived NADPH plays a role in augmenting O2− generation in diabetes. We assessed cardiac function, Nox and G6PD activities, NADPH levels, and the activities of antioxidant enzymes in heart homogenates from young (9–11 wk old) Zucker lean and obese (fa/fa) rats. We found that myocardial G6PD activity was significantly higher in fa/fa than in lean rats, whereas superoxide dismutase and glutathione peroxidase activities were decreased ( P < 0.05). O2− levels were elevated (70–90%; P < 0.05) in the diabetic heart, and this elevation was blocked by the Nox inhibitor gp-91ds-tat (50 μM) or by the mitochondrial respiratory chain inhibitors antimycin (10 μM) and rotenone (50 μM). Inhibition of G6PD by 6-aminonicotinamide (5 mM) and dihydroepiandrosterone (100 μM) also reduced ( P < 0.05) O2− production. Notably, the activities of Nox and G6PD in the fa/fa rat heart were inhibited by chelerythrine, a protein kinase C inhibitor. Although we detected no changes in stroke volume, cardiac output, or ejection fraction, left ventricular diameter was slightly increased during diastole and systole, and left ventricular posterior wall thickness was decreased during systole ( P < 0.05) in Zucker fa/fa rats. Our findings suggest that in a model of severe hyperlipidema and hyperglycemia Nox-derived O2− generation in the myocardium is fueled by elevated levels of G6PD-derived NADPH. Similar mechanisms were found to activate O2− production and induce endothelial dysfunction in aorta. Thus G6PD may be a useful therapeutic target for treating the cardiovascular disease associated with type 2 diabetes, if second-generation drugs specifically reducing the activity of G6PD to near normal levels are developed.


2007 ◽  
Vol 31 (1) ◽  
pp. 53-62 ◽  
Author(s):  
Junwu Mu ◽  
Dawei Qu ◽  
Agata Bartczak ◽  
M. James Phillips ◽  
Justin Manuel ◽  
...  

We hypothesized that cardiac dysfunction was responsible for the high perinatal lethality that we previously reported in fibrinogen-like protein 2 ( Fgl2) knockout (KO) mice. We therefore used ultrasound biomicroscopy to assess left ventricular (LV) cardiac structure and function during development in Fgl2 KO and wild-type (WT) mice. The only deaths observed between embryonic day (E)8.5 (onset of heart beating) and postnatal day (P)28 (weaning) were within 3 days after birth, when 33% of Fgl2 KO pups died. Histopathology and Doppler assessments suggested that death was due to acute congestive cardiac failure without evidence of valvular or other obvious cardiac structural abnormalities. Heart rates in Fgl2 KO embryos were significantly reduced at E8.5 and E17.5, and irregular heart rhythms were significantly more common in Fgl2 KO (21/26) than WT (2/21) embryos at E13.5. Indexes of systolic and/or diastolic cardiac function were also abnormal in KO mice at E13.5 and E17.5, in postnatal mice studied at P1, and in KO mice surviving to P28. M-mode analysis showed no difference in LV diastolic chamber dimension, although posterior wall thickness was thinner at P7 and P28 in Fgl2 KO mice. We conclude that Fgl2 deficiency is not associated with obvious structural cardiac defects but is associated with a high incidence of neonatal death as well as contractile dysfunction and rhythm abnormalities during embryonic and postnatal development in mice.


2019 ◽  
Vol 13 (4) ◽  
pp. 593-600
Author(s):  
María García-Manzanares ◽  
Estefanía Tarazón ◽  
Ana Ortega ◽  
Carolina Gil-Cayuela ◽  
Luis Martínez-Dolz ◽  
...  

AbstractTranscriptomic signature of XPO1 was highly expressed and inversely related to left ventricular function in ischemic cardiomyopathy patients. We hypothesized that treatment with AAV9-shXPO1 attenuates left ventricular dysfunction and remodeling in a myocardial infarction rat model. We induced myocardial infarction by coronary ligation in Sprague-Dawley rats (n = 10), which received AAV9-shXPO1 (n = 5) or placebo AAV9-scramble (n = 5) treatment. Serial echocardiographic assessment was performed throughout the study. After myocardial infarction, AAV9-shXPO1-treated rats showed partial recovery of left ventricular fractional shortening (16.8 ± 2.8 vs 24.6 ± 4.1%, P < 0.05) and a maintained left ventricular dimension (6.17 ± 0.95 vs 4.70 ± 0.93 mm, P < 0.05), which was not observed in non-treated rats. Furthermore, lower levels of EXP-1 (P < 0.05) and lower collagen fibers and fibrosis in cardiac tissue were observed. However, no differences were found in the IL-6 or TNFR1 plasma levels of the myocardium of AAV9-shXPO1 rats. AAV9-shXPO1 administration attenuates cardiac dysfunction and remodeling in rats after myocardial infarction, producing the gene silencing of XPO1.


Author(s):  
Satya Murthy Tadinada ◽  
Eric T. Weatherford ◽  
Greg V. Collins ◽  
Gourav Bhardwaj ◽  
Jesse Cochran ◽  
...  

Molecular mechanisms underlying cardiac dysfunction and subsequent heart failure in diabetic cardiomyopathy are incompletely understood. Initially we intended to test the role of GRK2, a potential mediator of cardiac dysfunction in diabetic cardiomyopathy, but found that control animals on HFD did not develop cardiomyopathy. Cardiac function was preserved in both wildtype and GRK2 knockout animals fed high fat diet as indicated by preserved left ventricular ejection fraction (LVEF) although heart mass was increased. The absence of cardiac dysfunction led us to rigorously evaluate the utility of diet-induced obesity to model diabetic cardiomyopathy in mice. Using pure C57BL/6J animals and various diets formulated with different sources of fat- lard (32% saturated fat, 68% unsaturated fat) or hydrogenated coconut oil (95% saturated fat), we consistently observed left ventricular hypertrophy, preserved LVEF and preserved contractility measured by invasive hemodynamics in animals fed high fat diet. Gene expression patterns that characterize pathological hypertrophy were not induced but a modest induction of various collagen isoforms and matrix metalloproteinases were observed in heart with high fat diet feeding. PPARa-target genes that enhance lipid utilization such as Pdk4, CD36, AcadL and Cpt1b were induced, but mitochondrial energetics were not impaired. These results suggest while long-term fat feeding in mice induces cardiac hypertrophy and increases cardiac fatty acid metabolism, it may not be sufficient to activate pathological hypertrophic mechanisms that impair cardiac function or induce cardiac fibrosis. Thus, additional factors that are currently not understood may contribute to the cardiac abnormalities previously reported by many groups.


2018 ◽  
Author(s):  
Rebecca Sullivan ◽  
Varinder K Randhawa ◽  
Anne Stokes ◽  
Derek Wu ◽  
Tyler Lalonde ◽  
...  

AbstractBackgroundCurrently, the early pre-clinical detection of left ventricular (LV) dysfunction is difficult as biomarkers are not specific for the cardiomyopathic process. The underlying molecular mechanisms leading to heart failure remain elusive, highlighting the need for identification of cardiac-specific markers. The growth hormone secretagogue receptor (GHSR) and its ligand ghrelin are present in cardiac tissue and are known to contribute to myocardial energetics. Here, we examined tissue ghrelin-GHSR levels as specific markers of cardiac dysfunction in patients who underwent cardiac transplantation.Methods and ResultsSamples of cardiac tissue were obtained from 10 cardiac transplant patients at the time of organ harvesting, and during serial post-transplant biopsies. Quantitative fluorescence microscopy using a novel fluorescent ghrelin analog was used to measure levels of GHSR, and immunofluorescence was used to measure levels of ghrelin, b-type natriuretic peptide (BNP) and tissue markers of cardiomyocyte contractility and growth. GHSR and ghrelin expression levels were highly variable in the explanted heart, less in the grafted heart biopsies. GHSR and ghrelin were strongly positively correlated, and both markers were negatively correlated with LV ejection fraction. Ghrelin had stronger positive correlations than BNP with the signaling markers for contractility and growth.ConclusionsThese data suggest that GHSR-ghrelin have potential use as an integrated marker of cardiac dysfunction. Interestingly, tissue ghrelin appeared to be a more sensitive indicator than BNP to the biochemical processes that are characteristic of heart failure. This work allows for further use of ghrelin-GHSR to interrogate cardiac-specific biochemical mechanisms in pre-clinical stages of HF.PrecisThis study shows the relationships between GHSR, ghrelin, and signaling molecules with relation to heart function in human heart failure with tissue from diseased heart and healthy heart biopsies.


1993 ◽  
Vol 11 (6) ◽  
pp. 1033-1038 ◽  
Author(s):  
R I Jakacki ◽  
J W Goldwein ◽  
R L Larsen ◽  
G Barber ◽  
J H Silber

PURPOSE Although spinal irradiation used in the treatment of CNS malignancies includes a portion of the heart in the radiation field, cardiac effects have not been previously reported. PATIENTS AND METHODS We compared patients treated for malignancy in childhood with spinal irradiation (n = 26) with patients treated with mediastinal/flank irradiation (n = 47) that included the heart in the radiation field. All patients were more than 1 year from completion of radiation therapy. Patients underwent at least two of the following cardiac evaluations: (1) ECG; (2) 24-hour ambulatory ECG; (3) echocardiogram; and (4) exercise-testing using cycle ergometry. RESULTS Twelve of 16 patients (75%) in the spinal irradiation group with an assessable exercise test achieved a maximal cardiac index (MCI) below the fifth percentile as compared with 13 of 40 patients (32%) who had received mediastinal/flank irradiation (P = .007). Furthermore, after adjusting for normal heart growth, radiation and anthracycline doses, and follow-up time, the group of patients who received spinal irradiation had significantly higher estimated posterior wall stress (P = .002), expressed as the natural logarithm of the ratio of end-diastolic left ventricular internal diameter (LVID) to left ventricular posterior wall thickness (LVPWT), than the group who had received mediastinal/flank irradiation. Finally, eight of 26 patients (31%) in the spinal group had pathologic Q-waves in the inferior leads versus three of 47 (6.4%) in the mediastinal/flank group (P = .001). CONCLUSION Patients who have received spinal irradiation for pediatric malignancies appear to be at risk for significant cardiac dysfunction. The asymmetric distribution of radiation to a growing heart, as given with spinal irradiation, may be the cause of these findings.


2013 ◽  
Vol 305 (10) ◽  
pp. R1102-R1111 ◽  
Author(s):  
I. Tong Mak ◽  
Jay H. Kramer ◽  
Xi Chen ◽  
Joanna J. Chmielinska ◽  
Christopher F. Spurney ◽  
...  

Use of protease inhibitors (PI) in HIV patients is associated with hyperlipidemia and increased risk of coronary heart disease. Chronic systemic and cardiac effects of ritonavir (RTV), a universal PI booster, and Mg supplementation were examined. RTV was administered (75 mg·kg−1·day−1 po) to Lewis×Brown-Norway hybrid (LBNF1) rats for up to 8 wk; significant increases in plasma triglyceride and cholesterol occurred from 8 days to 8 wk. At 5 wk, the expression of selected hepatic genes ( CYP7A1, CITED2, G6PC, and ME-1), which are key to lipid catabolism/synthesis, were altered toward lipogenesis. Dietary Mg supplementation (six-fold higher) completely reversed the altered expression of these genes and attenuated both hypertriglyceridemia and hypercholesterolemia. Neutrophils isolated from the RTV-treated rats displayed a three-fold higher basal and a twofold higher stimulated superoxide production; plasma isoprostane and red blood cell (RBC) GSSG levels were elevated two- to three-fold. All oxidative indices were normalized by Mg supplementation. After 5 wk, RTV caused significant decreases in cardiac left ventricular (LV) shortening fraction and LV ejection fraction; mitral valve early/late atrial ventricular filling (E/A) ratio was reduced accompanied by LV posterior wall thinning. Immunohistochemical staining revealed significant white blood cell (WBC) infiltration (5 wk) and prominent fibrosis (8 wk) in the RTV hearts. Mg supplementation attenuated RTV-induced declines in systolic and diastolic (improved mitral valve E/A ratio) function (>70%), lessened LV posterior wall thinning (by 75%), and substantially decreased the pathological markers. The known clinical hyperlipidemia effects of RTV can be mimicked in the LBNF1 rats; in association, systemic oxidative stress and progressive cardiac dysfunction occurred. Remarkably, Mg supplementation alone suppressed RTV-mediated hyperlipidemia, oxidative stress, and cardiac dysfunction.


2021 ◽  
Vol 5 (Supplement_1) ◽  
pp. A660-A661
Author(s):  
Daniel Mak ◽  
Kaitlin A Ryan ◽  
Joan C Han

Abstract Children with cardiomyopathy are a vulnerable population and understanding the factors that contribute to cardiac dysfunction are of great importance. At the biochemical level, energy utilization by cardiomyocytes during stress may provide insight into the progression of cardiomyopathy. There is a large body of literature that describes insulin resistance in adults with cardiomyopathy (1,2). Extensive literature on the topic in adult individuals exists however investigation in the pediatric population is sparse. The pathophysiology of disease in children and adolescents is unique. To study the role of insulin resistance in pediatric cardiomyopathy, we measured the homeostasis model assessment-estimated insulin resistance (HOMA-IR) at baseline in pre-pubertal patients (age 13-18 years old; mean 16 years old; n = 8) with either hypertrophic cardiomyopathy (HCM) or dilated cardiomyopathy (DCM). In patients with HCM, greater insulin resistance was positively correlated with greater left ventricular (LV) septal thickness (r = 0.55; p = 0.33; n = 5) and LV posterior wall thickness (r = 0.7; p = 0.19; n = 5) during diastole. As expected, insulin resistance was strongly correlated with BMI (r = 0.84; p = 0.08; n = 5) though greater BMI was not as strongly associated with LV septal thickness (r = 0.59; p = 0.3; n = 5) or posterior wall thickness (r = 0.59; p = 0.3; n = 5). In patients with DCM, insulin resistance was positively correlated with LV end diastolic volume (r = 0.59; p = 0.59; n = 3). Interestingly, there was an observed inverse association between insulin resistance and BMI in DCM (r = -0.85; p = 0.34; n =3). Though our sample population is limited, thus affecting statistical significance, results showed that there was a trend towards greater insulin resistance in patients with poorer cardiac measurements. These findings are consistent with adult literature and the proposition that cardiac dysfunction is an insulin resistant state. References: (1) Riehle C, Abel ED. Insulin Signaling and Heart Failure. Circulation research. 2016;118(7):1151-1169. (2) Shah A, Shannon RP. Insulin resistance in dilated cardiomyopathy. Reviews in cardiovascular medicine. 2003;4 Suppl 6:S50-57


2020 ◽  
Vol 19 (2) ◽  
pp. 181-187
Author(s):  
Jing Li ◽  
Yun Zhang ◽  
Weizhong Huangfu ◽  
Yuhong Ma

Using rat models of heart failure, we evaluated the effects of rosuvastatin and Huangqi granule alone and in combination on left ventricular end-diastolic dimension, left ventricular end-systolic dimension, left ventricular ejection fraction, left ventricular posterior wall thickness at end-diastole, and left ventricular posterior wall thickness at end-systole. Results showed that left ventricular end-diastolic dimension, left ventricular end-systolic dimension in the rosuvastatin + Huangqi granule group were significantly decreased (P ‹ 0.01), while left ventricular ejection fraction, left ventricular posterior wall thickness at end-diastole and left ventricular posterior wall thickness at end-systole were significantly increased (P ‹ 0.05). The serum IL-2, IFN-β, and TNF-α in rosuvastatin + Huangqi granule group were significantly lower than those in model group (P ‹ 0.05). However, the levels of S-methylglutathione and superoxide dismutase in rosuvastatin + Huangqi granule group were significantly higher, while nitric oxide was significantly lower than that in the model group (P ‹ 0.05). Also, compared to the model group, the apoptosis rate, and the autophagy protein LC3-II in the cardiomyocytes of rosuvastatin + Huangqi granule group was significantly decreased (P ‹ 0.01), while the level of p62 protein was significantly increased (P ‹ 0.01). The levels of AMPK and p-AMPK in cardiomyocytes were significantly lower in rosuvastatin + Huangqi granule group; however, the levels of mTOR and p-mTOR showed an opposite trend (P ‹ 0.05). To sum up, rosuvastatin + Huangqi granule could improve the cardiac function, decrease the level of oxidative stress, and inflammatory cytokines in rats with HF. The possible underlying mechanism might be inhibition of autophagy and reduced apoptosis in cardiomyocytes by regulating AMPK-mTOR signaling pathway.


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