P3478Glucose-dependent insulinotropic peptide is essential for maintenance of cardiac lipid metabolism via FGF21-dependent pathway

2019 ◽  
Vol 40 (Supplement_1) ◽  
Author(s):  
Y Remina ◽  
Y Kureishi Bando ◽  
R Ozaki ◽  
T Kamihara ◽  
K Nishimura ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Left Ventricular ◽  
Insulin Biosynthesis ◽  
Fibroblast Growth Factor 21 ◽  
Tunel Staining ◽  
Triglyceride Accumulation ◽  
Sensitive Organ ◽  
Cardiac Steatosis ◽  
Insulinotropic Peptide ◽  
And Oxidative Stress

Abstract Background/Introduction Incretin hormones, glucagon-like peptide 1 (GLP-1) and glucose-dependent insulinotropic peptide (GIP) are secreted from the small intestine and emerged as important participants in glucose homeostasis that involves in the pathogenesis of type 2 diabetes (T2D). stimulate glucose-dependent insulin biosynthesis. Emerging data suggest important extrapancreatic functions for GLP-1 on cardiovascular system. However, limited evidence has been emerged whether GIP may play any pathophysiological role in heart. GIP promotes insulin secretion leading to augment insulin-induced lipogenesis. Recent research has highlighted the relevance of the GIP/GIPR axis in principal insulin-sensitive organs such as adipose tissue. Heart is another insulin-sensitive organ in which insulin promotes hypertrophy of myocardium presumably via activation of Akt pathway. In T2DM, ectopic accumulation of lipid and fat to myocardium that is known as “cardiac steatosis”; however, it remains uncertain whether the GIP/insulin axis may modulate cardiac steatosis observed in T2DM. Purpose To elucidate that physiological GIP may play a regulatory role in cardiac pathophysiology. Methods We employed mouse model of GIPR deficiency (GIPR-KO) that was generated by lacking the GIPR gene (GIPR), by replacing exons 4 and 5 of GIPR with the PGK-neo cassette. Cardiac evaluation of GIPR-KO was performed at the age of 6 week-old (w/o), 10 w/o, 23 w/o, and 53 w/o. Results GIPR deficient mice (GIPR-KO) exhibited normoglycemia, but their circulating free acid level and ketone level were elevated. Interestingly, GIPR-KO at younger age (6-week-old and 10-week old) exhibited normal left-ventricular (LV) function, however, older mice aged older than 20-week-old exhibited significant systolic left-ventricular dysfunction (FS (%) 55.2±1.9 for Wild-type, 32.1±2.6 for 23-w/o-GIPR-KO, 28.5±2.6 for 56-w/o-GIPR-KO, P<0.01). Histological analysis revealed that cardiomyocyte size was decreased and capillary density was increased in GIPR-KO. Interestingly, TUNEL staining revealed that there was no increase in cardiac apoptosis in GIPR-KO. In contrast, GIPR-KO exhibited increase in cardiac fibrosis (Picro-sirius staining) and oxidative stress (DHE staining). Myocardial triglyceride accumulation was decreased in GIPR-KO heart. QPCR analysis revealed GIPR-KO heart exhibited increase in BNP level and decline in fibroblast growth factor 21 (FGF-21), an hormonal activator for energy expenditure in adipocyte. GIP augmented FGF-21 expression in cardiomyocytes via PPARalfa. Conclusion Loss of GIP signaling caused impaired fatty acid metabolism in heart via impairment of FGF21 pathway and oxidative stress, leading to an age-dependent progression of cardiac dysfunction.

The aging-induced hyperexcretion of glucose-dependent insulinotropic peptide is essential for the healthy cardiac remodeling by prevention of cardiac ceramide accumulation

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
Y Kureishi Bando ◽  
Y.R Remina ◽  
T.K Kamihara ◽  
K.N Nishimura ◽  
T.M Murohara
Keyword(s):  
Oxidative Stress ◽  
Ketone Bodies ◽  
Left Ventricular ◽  
Heart Weight ◽  
Lv Function ◽  
Cardiac Aging ◽  
Normal Left Ventricular ◽  
Insulinotropic Peptide ◽  
Ceramide Accumulation ◽  
And Oxidative Stress

Abstract Background Glucose-dependent insulinotropic peptide (GIP) is incretin hormone that is emerged as an important regulator of lipid metabolism. Fat intake induces hypersecretion of GIP that is involved in obesity and ectopic fat accumulation. Aging is another stimulant of GIP hypersecretion, which is suggested as a cause of “sarcopenic obesity in elderly”. In heart, aging is the known risk factor of HFpEF, of which typical characteristics is pathological cardiac hypertrophy induced by unknown cause(s). It remained uncertain whether any ectopic fat accumulation, such as cardiac steatosis may cause the aging-induced cardiac hypertrophy. Ceramide is one of the lipid metabolites that involves in apoptosis, inflammation, and stress responses, which are among the pathogenic components of heart failure. However, it remained unclear whether the ceramide may play any pathophysiological role in cardiac aging. Purpose We thus hypothesized whether cardiac aging may alter cardiac lipid metabolism and the GIP may play a regulatory role in the cardiac aging via modulating cardiac steatosis, particularly ceramide. Methods Mouse model of GIPR deficiency (GIPR-KO) was employed and cardiac evaluation of GIPR-KO and the age-matched wild type mice were performed. Results Aging (50w/o) induced GIP hypersecretion in control mice and their body and heart weight were 50% increased as compared to younger counterpart (10w/o). In contrast, the aging-induced increase rate in body and heart weight of GIPR-KO was significantly lower (22%). Aging also increased the circulating ketone bodies with increase in FGF21 expression in heart and, notably, there was no pathological increase in cardiac ceremide and oxidative stress with normal left-ventricular (LV) function (LVEF=82.2±1.8). In contrast, GIPR-KO exhibited pathological increase in cardiac ceramide without the elevation of the circulating ketone bodies. The younger GIPR-KO (10 w/o) exhibited normal left-ventricular (LV) function, however, the older mice (50 w/o) exhibited systolic LV dysfunction (LVEF=55.8±8.5) with increase in cardiac apoptosis and oxidative stress. Cardiac ceramide accumulation was increased in the aged normal mice, which was significantly higher in the aged GIPR-KO. Furthermore, GIPR-KO exhibited increase in cardiac fibrosis and oxidative stress, which were absent in the aged normal counterpart. Conclusion Aging increased circulating GIP level the leads to compensatory rise in the circulating ketone bodies without pathological increase in cardiac ceremide and related oxidative stress in heart. Loss of GIP signaling caused pathological increase in cardiac ceramide, leading to the aging-induced progression of systolic left-ventricular dysfunction. Collectively, we conclude that the aging-induced GIP hyperexcretion is essential for the aging-induced healthy cardiac remodeling by augmenting compensatory ketone body elevation. Funding Acknowledgement Type of funding source: Public grant(s) – National budget only. Main funding source(s): KAKEN-HI

AKAP150 mobilizes cPKC-dependent cardiac glucotoxicity

2014 ◽  
Vol 307 (4) ◽  
pp. E384-E397 ◽  
Author(s):  
Chao Zeng ◽  
Jinyi Wang ◽  
Na Li ◽  
Mingzhi Shen ◽  
Dongjuan Wang ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
High Glucose ◽  
Myocardial Dysfunction ◽  
Left Ventricular ◽  
Cardiomyocyte Apoptosis ◽  
Neonatal Rat ◽  
Tunel Staining ◽  
Rat Cardiomyocytes ◽  
Intramyocardial Injection ◽  
And Oxidative Stress

Activation of conventional PKCs (cPKC) is a key signaling that directs the cardiac toxicity of hyperglycemia. AKAP150, a scaffold protein of the A-kinase anchoring proteins (AKAPs) family, is less defined regarding its capability to anchor and regulate cardiac cPKC signaling. This study was designed to investigate the role of AKAP150 in cPKC-mediated cardiac glucotoxicity. In cardiac tissues from streptozotocin-induced diabetic rats and high-glucose-treated neonatal rat cardiomyocytes, both mRNA and protein levels of AKAP150 increased significantly, and marked elevations were observed in cPKC activity and both expression and phosphorylation levels of p65 NF-κB and p47phox. AKAP150 knockdown was established via intramyocardial injection in vivo and transfection in vitro of adenovirus carrying AKAP150-targeted shRNA. Downregulation of AKAP150 reversed diabetes-induced diastolic dysfunction as manifested by decreased left ventricular end-diastolic diameter and early/late mitral diastolic wave ratio. AKAP150 inhibition also abrogated high-glucose-induced cardiomyocyte apoptosis (TUNEL staining and annexin V/propidium iodide flow cytometry) and oxidative stress (ROS production, NADPH oxidase activity, and lipid peroxidation). More importantly, reduced AKAP150 expression significantly inhibited high-glucose-induced membrane translocation and activation of cPKC and suppressed the increases in the phosphorylation of p65 NF-κB and p47phox. Immunofluorescent coexpression and immunoprecipitation indicated enhanced anchoring of AKAP150 with cPKC within the plasma membrane under hyperglycemia, and AKAP150 preferentially colocalized and functionally bound with PKCα and -β isoforms. These results suggest that cardiac AKAP150 positively responds to hyperglycemia and enhances the efficiency of glucotoxicity signaling through a cPKC/p47phox/ROS pathway that induces myocardial dysfunction, cardiomyocyte apoptosis, and oxidative stress.

Abstract 12526: AKAP150-Mobilized PKC Activation Mediates Myocardial Dysfunction in Diabetes

Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Zeng Chao ◽  
Jinyi Wang ◽  
Na Li ◽  
Mingzhi Shen ◽  
Haichang Wang ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
High Glucose ◽  
Myocardial Dysfunction ◽  
Left Ventricular ◽  
Cardiomyocyte Apoptosis ◽  
Neonatal Rat ◽  
Tunel Staining ◽  
Rat Cardiomyocytes ◽  
Intramyocardial Injection ◽  
And Oxidative Stress

Background: Chronic activation of conventional PKC (cPKC) is a key signaling that directs the cardiac toxicity of hyperglycemia. AKAP150, a scaffold protein of the A-kinase anchoring proteins (AKAPs) family, is less defined regarding its capability to anchor and regulate cPKC signaling in cardiomyocytes. This study was aimed to investigate the role of AKAP150 in cPKC-mediated cardiac injury in diabetes. Methods and Results: In cardiac tissues from streptozotocin-induced diabetic rats and high-glucose treated neonatal rat cardiomyocytes, expression of AKAP150 increased significantly at both mRNA and protein levels, with a marked elevation in expression and activity of cPKC and phosphorylation levels of p65NF-κB and p47phox. AKAP150 knockdown was established via intramyocardial injection in vivo and transfection in vitro of adenovirus carrying AKAP150 targeted shRNA. Downregulation of AKAP150 reversed diabetes-induced diastolic dysfunction, as evidenced by decreased left ventricular end-diastolic diameter and early/late mitral diastolic wave ratio. AKAP150 inhibition also abrogated high-glucose induced cardiomyocyte apoptosis (TUNEL staining and annexin V/PI flow cytometry) and oxidative stress (ROS production, NADPH oxidase activity and lipid peroxidation). More importantly, reduced AKAP150 expression significantly reversed high-glucose induced membrane translocation and activation of cPKC, and inhibited phosphorylation of p65NF-κB and p47phox. Immunofluorescent co-expression and immunoprecipitation analysis indicated enhanced anchoring of AKAP150 with cPKC within the plasma membrane in both diabetic myocardium and high-glucose treated cardiomyocytes. Further studies using antibodies and specific inhibitors against different cPKC isoforms revealed that AKAP150 preferentially co-localized and functionally bound with PKC α and β, which are the major isoforms responsible for cardiac glucotoxicity. Conclusions: Cardiac AKAP150 positively responds to hyperglycemic stimuli and functions to enhance the efficiency of glucotoxicity signaling through a cPKC/p47phox/ROS pathway that induces myocardial dysfunction, cardiomyocyte apoptosis and oxidative stress.

scholarly journals IL-23 Promotes Myocardial I/R Injury by Increasing the Inflammatory Responses and Oxidative Stress Reactions

2016 ◽  
Vol 38 (6) ◽  
pp. 2163-2172 ◽  
Author(s):  
Xiaorong Hu ◽  
Ruisong Ma ◽  
Jiajia Lu ◽  
Kai Zhang ◽  
Weipan Xu ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Inflammatory Responses ◽  
Tunel Staining ◽  
Ischemia And Reperfusion ◽  
Stress Reactions ◽  
Sprague Dawley ◽  
Sod Activity ◽  
Myocardial Ischemia And Reperfusion ◽  
Tnf Α ◽  
And Oxidative Stress

Background/Aims: Inflammation and oxidative stress play an important role in myocardial ischemia and reperfusion (I/R) injury. We hypothesized that IL-23, a pro-inflammatory cytokine, could promote myocardial I/R injury by increasing the inflammatory response and oxidative stress. Methods: Male Sprague-Dawley rats were randomly assigned into sham operated control (SO) group, ischemia and reperfusion (I/R) group, (IL-23 + I/R) group and (anti-IL-23 + I/R) group. At 4 h after reperfusion, the serum concentration of lactate dehydrogenase (LDH), creatine kinase (CK) and the tissue MDA concentration and SOD activity were measured. The infarcte size was measured by TTC staining. Apoptosis in heart sections were measured by TUNEL staining. The expression of HMGB1 and IL-17A were detected by Western Blotting and the expression of TNF-α and IL-6 were detected by Elisa. Results: After 4 h reperfusion, compared with the I/R group, IL-23 significantly increased the infarct size, the apoptosis of cardiomyocytes and the levels of LDH and CK (all P < 0.05). Meanwhile, IL-23 significantly increased the expression of eIL-17A, TNF-α and IL-6 and enhanced both the increase of the MDA level and the decrease of the SOD level induced by I/R (all P<0.05). IL-23 had no effect on the expression of HMGB1 (p > 0.05). All these effects were abolished by anti-IL-23 administration. Conclusion: The present study suggested that IL-23 may promote myocardial I/R injury by increasing the inflammatory responses and oxidative stress reaction.

scholarly journals Liraglutide protects cardiac function in diabetic rats through the PPARα pathway

2018 ◽  
Vol 38 (2) ◽  
Author(s):  
Qian Zhang ◽  
Xinhua Xiao ◽  
Jia Zheng ◽  
Ming Li ◽  
Miao Yu ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Insulin Resistance ◽  
Cardiac Dysfunction ◽  
Diabetic Rats ◽  
Left Ventricular ◽  
Serum Adiponectin ◽  
Diabetic Rat ◽  
Lv Function ◽  
High Dose ◽  
And Oxidative Stress

Increasing evidence shows that diabetes causes cardiac dysfunction. We hypothesized that a glucagon-like peptide-1 (GLP-1) analog, liraglutide, would attenuate cardiac dysfunction in diabetic rats. A total of 24 Sprague–Dawley (SD) rats were divided into two groups fed either a normal diet (normal, n=6) or a high-fat diet (HFD, n=18) for 4 weeks. Then, the HFD rats were injected with streptozotocin (STZ) to create a diabetic rat model. Diabetic rats were divided into three subgroups receiving vehicle (diabetic, n=6), a low dose of liraglutide (Llirag, 0.2 mg/kg/day, n=6), or a high dose of liraglutide (Hlirag, 0.4 mg/kg/day, n=6). Metabolic parameters, systolic blood pressure (SBP), heart rate (HR), left ventricular (LV) function, and whole genome expression of the heart were determined. Diabetic rats developed insulin resistance, increased blood lipid levels and oxidative stress, and impaired LV function, serum adiponectin, nitric oxide (NO). Liraglutide improved insulin resistance, serum adiponectin, NO, HR, and LV function and reduced blood triglyceride (TG), total cholesterol (TC) levels, and oxidative stress. Moreover, liraglutide increased heart nuclear receptor subfamily 1, group H, member 3 (Nr1h3), peroxisome proliferator activated receptor (Ppar) α (Pparα), and Srebp expression and reduced diacylglycerol O-acyltransferase 1 (Dgat) and angiopoietin-like 3 (Angptl3) expression. Liraglutide prevented cardiac dysfunction by activating the PPARα pathway to inhibit Dgat expression and oxidative stress in diabetic rats.

Abstract 1378: NFkb Blockade Attenuate Cytokines And Oxidative Stress In The Paraventricular Nucleus And Decreases Neurohumoral Excitation In Spontaneously Hypertensive Rats

Circulation ◽  
2007 ◽  
Vol 116 (suppl_16) ◽  
Author(s):  
Nithya Mariappan ◽  
Carrie Elks ◽  
Masudul Haque ◽  
Philip J Ebnezer ◽  
Elizabeth McIIwain ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Blood Pressure ◽  
Paraventricular Nucleus ◽  
Spontaneously Hypertensive Rats ◽  
Left Ventricular ◽  
Oxidative Stress Markers ◽  
Hypertensive Rats ◽  
Spontaneously Hypertensive ◽  
Stress Markers ◽  
And Oxidative Stress

The transcriptional factor, nuclear factor kappa B (NFkB) plays an important role in the regulation of cytokines. Among the cytokines, tumor necrosis factor-alpha (TNF) plays an important role in cardiovascular pathophysiology. This study was done to determine whether TNF-α blockade with etanercept (ETN) or NFkB blockade with dithiol pyrolidine thiocarbamate (PDTC) attenuate oxidative stress in the paraventricular nucleus (PVN) and contribute to neurohumoral excitation in spontaneously hypertensive rats. Method: Male 20 week old SHR rats were treated with ETN (1 mg/kg BW, sc) or PDTC (100mg/kg BW, ip) for 5 week period. Left ventricular function was measured at baseline (20 weeks) and at 25 weeks using echocardiography. Blood pressure was measured at weekly intervals throughout the study. At the end of the protocol rats were sacrificed the PVN was microdissected for the measurement of cytokines, oxidative stress markers using real time PCR (fold increase compared to WKY controls) and by immunohistochemistry. Superoxide, total reactive oxygen species and peroxynitrite were measured in the PVN and LV using electron paramagnetic resonance. Plasma norepinephrine and epinephrine an indicator of neurohumoral excitation was measured using HPLC-EC. Results: PVN data are tabulated. SHR animals had increased expression of protein and mRNA for cytokines and oxidative stress markers in the PVN and LV with increased MAP and cardiac hypertrophy when compared to WKY rats. Treatment with ETN and PDTC attenuated these increases with PDTC showing marked effect than ETN on hypertrophy and blood pressure responses. Conclusion: These findings suggest that cytokine activation in the PVN contributes to increased oxidative stress and neurohumoral excitation in hypertension.

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