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GÜZ G, OFLAZ H. Effects of Exercise On Coronary Flow Reserve And Biochemical Parameters in Patients With Type 2 Diabetes Mellitus. ARCHIVES OF CLINICAL AND EXPERIMENTAL MEDICINE 2022. [DOI: 10.25000/acem.1145353] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The most important mortality and morbidity causes in diabetic patients are coronary, peripheral and cerebral diseases. The aim of our study was to noninvasively determine dysfunction in epicardial coronary arteries and microvascular circulation with measurement of coronary flow reserve using transthoracic echocardiography in patients with type 2 diabetes despite absence of ischemic symptoms, and to demonstrate the amelioration in endothelial functions, glycemic control and insulin resistance along with increase in coronary flow reserve after 8 weeks of regular exercise. 40 patients diagnosed with type 2 diabetes in Istanbul Facuty of Medicine, Department of Diabetes, who were on follow-up for at least three years due to diabetes, without ischemic symptoms and 20 healthy subjects took part in study. Basal values before exercise of diabetic patients who were included in the exercise program were compared with basal values of diabetic patients who did not exercise regularly. To summarize, regular exercise and physical activity are highly important in diabetic patients for primary and secondary protection against cardiovascular incidents. Physical activity increases insulin sensitivity in diabetic patients, and has many positive effects on glucose metabolism. It is the important way to decrease obesity and visceral fat tissue. There is evidence pointing out that regular exercise can defer or even prevent initiation of diabetes.
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Affiliation(s)
- Göksel GÜZ
- BEYLİKDÜZÜ MEDİCANA İNTERNATİONAL HASTANESİ
| | - Hüseyin OFLAZ
- İSTANBUL ÜNİVERSİTESİ, İSTANBUL TIP FAKÜLTESİ, İSTANBUL TIP PR
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2
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Heydarnia E, Taghian F, Jalali Dehkordi K, Moghadasi M. Regular combined training and vitamins modulated the apoptosis process in diabetic rats: Bioinformatics analysis of heart failure's differential genes expression network correlated with anti-apoptotic process. J Food Biochem 2022; 46:e14291. [PMID: 35780321 DOI: 10.1111/jfbc.14291] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2022] [Revised: 05/09/2022] [Accepted: 05/17/2022] [Indexed: 02/06/2023]
Abstract
The apoptosis process could impose significantly by hyperglycemia. According to in silico language processing and high throughput raw data analysis, we recognized hub molecular mechanisms involved in the pathogenesis of diabetic hearts and suggested a new pharmaceutical approach for declining myocardial programed cell death. Fifty male Sprague-Dawley rats were classified into five groups: healthy rats as control, diabetic rats, diabetic combined resistance/endurance training, diabetic rats which consumed supplementation vitamins E and C, and the combined supplementation and training. Here, we calculated changes in gene expression based on artificial intelligence methods and evaluated gene expression in apoptotic influencing combined training and antioxidants vitamins consumption in heart injured models by streptozotocin via Real-Time PCR. Moreover, we assessed the binding affinity of the 3D structure of small molecules on macromolecule SIRT3 to a new compound pharmaceutical suggesting the decline in cell death program. The computational intelligence surveys revealed that the apoptosis process was a remarkable pathomechanism in the abnormality function of heart tissue in diabetic conditions. Furthermore, we showed that synchronizing antioxidant vitamin consumption and regular combined training could significantly decrease irreversible myocardial cell death in diabetic myocardiopathy. Hence, levels of antiapoptotic mRNA were modified in the combined training/vitamin consumption group compared with other classifications. We found that regular combined exercise and vitamin consumption could reverse the apoptosis process to enhance the survival of cardiac muscle cells in diabetes conditions. PRACTICAL APPLICATIONS: Machine learning and system biology indicated that the apoptosis process is a vital pathomechanism of hyperglycemia-induced heart failure. Sirt3/Fas/Bcl-2/Cycs and Bax, as a critical network of apoptosis, play an essential role in heart failure induced by hyperglycemia. Moreover, Type 2 diabetes and obesity increase the risk of heart failure by increasing high blood sugar levels. We calculated the binding power of the vitamins E and C on SIRT3 protein based on the drug software. In addition, this study assessed that regular combined training and vitamin consumption had an antiapoptotic effect. Also, our data might improve the hyperglycemia state.
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Affiliation(s)
- Elaheh Heydarnia
- Department of Sports Physiology, Faculty of Sports Sciences, Isfahan (Khorasgan) Branch, Islamic Azad University, Isfahan, Iran
| | - Farzaneh Taghian
- Department of Sports Physiology, Faculty of Sports Sciences, Isfahan (Khorasgan) Branch, Islamic Azad University, Isfahan, Iran
| | - Khosro Jalali Dehkordi
- Department of Sports Physiology, Faculty of Sports Sciences, Isfahan (Khorasgan) Branch, Islamic Azad University, Isfahan, Iran
| | - Mehrzad Moghadasi
- Department of Physical Education and Sports Sciences, Shiraz Branch, Islamic Azad University, Shiraz, Iran
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3
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Prokineticin 2 (PK2) Rescues Cardiomyocytes from High Glucose/High Palmitic Acid-Induced Damage by Regulating the AKT/GSK3 β Pathway In Vitro. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2020; 2020:3163629. [PMID: 32509142 PMCID: PMC7251470 DOI: 10.1155/2020/3163629] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Revised: 02/20/2020] [Accepted: 03/10/2020] [Indexed: 12/14/2022]
Abstract
Prokineticin 2 (PK2) is a small 8 kDa protein that participates in many physiological processes, such as angiogenesis, inflammation, and neurogenesis. This experiment investigated the effect of PK2 on high glucose/high palmitic acid-induced oxidative stress, apoptosis, and autophagy in cardiomyocytes and the AKT/GSK3β signalling pathway. H9c2 cells were exposed to normal and high concentrations (33 mM) of glucose and palmitic acid (150 μM) with or without PK2 (10 nM) for 48 h. Reactive oxygen species were detected using the fluorescent probes DCFH-DA and DHE. Changes in apoptosis were assessed using flow cytometry, and autophagosomes were detected using Ad-GFP-LC3. Apoptotic proteins, such as Cleaved Caspase3, Bax, and Bcl-2; autophagy proteins, including Beclin-1 and LC3B; and PK2/PKR/AKT/GSK3β signals were evaluated using western blotting. Cardiomyocytes exposed to high glucose/high palmitic acid exhibited increases in intracellular ROS, apoptosis, and autophagosomes, and these increases were robustly prevented by PK2. In addition, high glucose/high palmitic acid remarkably suppressed PK2, PKR1, and PKR2 expression and p-AKT/AKT and p-GSK3β/GSK3β ratios, and these effects were significantly prevented by PK2. Moreover, an AKT1/2 kinase inhibitor (AKT inhibitor, 10 μM) blocked the effects of PK2 on the changes in cardiomyocyte exposure to high glucose/high palmitic acid. These results suggest that PK2 attenuates high glucose/high palmitic acid-induced cardiomyocyte apoptosis by inhibiting oxidative stress and autophagosome accumulation and that this protective effect is most likely mediated by the AKT-related signalling pathway.
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Babaee Bigi MA, Faramarzi H, Gaeini AA, Ravasi AA, Izadi MR, Delfan M, Izadi E. Upregulation of Ryanodine Receptor Calcium Channels (RyR2) in Rats with Induced Diabetes after 4 Weeks of High Intensity Interval Training. Int Cardiovasc Res J 2016. [DOI: 10.17795/icrj-10(1)1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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5
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Ren J, Anversa P. The insulin-like growth factor I system: physiological and pathophysiological implication in cardiovascular diseases associated with metabolic syndrome. Biochem Pharmacol 2014; 93:409-17. [PMID: 25541285 DOI: 10.1016/j.bcp.2014.12.006] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2014] [Revised: 12/11/2014] [Accepted: 12/11/2014] [Indexed: 12/31/2022]
Abstract
Metabolic syndrome is a cluster of risk factors including obesity, dyslipidemia, hypertension, and insulin resistance. A number of theories have been speculated for the pathogenesis of metabolic syndrome including impaired glucose and lipid metabolism, lipotoxicity, oxidative stress, interrupted neurohormonal regulation and compromised intracellular Ca(2+) handling. Recent evidence has revealed that adults with severe growth hormone (GH) and insulin-like growth factor I (IGF-1) deficiency such as Laron syndrome display increased risk of stroke and cardiovascular diseases. IGF-1 signaling may regulate contractility, metabolism, hypertrophy, apoptosis, autophagy, stem cell regeneration and senescence in the heart to maintain cardiac homeostasis. An inverse relationship between plasma IGF-1 levels and prevalence of metabolic syndrome as well as associated cardiovascular complications has been identified, suggesting the clinical promises of IGF-1 analogues or IGF-1 receptor activation in the management of metabolic and cardiovascular diseases. However, the underlying pathophysiological mechanisms between IGF-1 and metabolic syndrome are still poorly understood. This mini-review will discuss the role of IGF-1 signaling cascade in the prevalence of metabolic syndrome in particular the susceptibility to overnutrition and sedentary life style-induced obesity, dyslipidemia, insulin resistance and other features of metabolic syndrome. Special attention will be dedicated in IGF-1-associated changes in cardiac responses in various metabolic syndrome components such as insulin resistance, obesity, hypertension and dyslipidemia. The potential risk of IGF-1 and IGF-1R stimulation such as tumorigenesis is discussed. Therapeutic promises of IGF-1 and IGF-1 analogues including mecasermin, mecasermin rinfabate and PEGylated IGF-1 will be discussed.
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Affiliation(s)
- Jun Ren
- Shanghai Institute of Cardiovascular Diseases, Zhongshan Hospital, Fudan University, Shanghai 200032, China; Center for Cardiovascular Research and Alternative Medicine, University of Wyoming College of Health Sciences, Laramie, WY 82071, USA.
| | - Piero Anversa
- Departments of Anesthesia and Medicine and Cardiovascular Division, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
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Dostal DE, Feng H, Nizamutdinov D, Golden HB, Afroze SH, Dostal JD, Jacob JC, Foster DM, Tong C, Glaser S, Gerilechaogetu F. Mechanosensing and Regulation of Cardiac Function. ACTA ACUST UNITED AC 2014; 5:314. [PMID: 25485172 PMCID: PMC4255974 DOI: 10.4172/2155-9880.1000314] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The role of mechanical force as an important regulator of structure and function of mammalian cells, tissues, and organs has recently been recognized. However, mechanical overload is a pathogenesis or comorbidity existing in a variety of heart diseases, such as hypertension, aortic regurgitation and myocardial infarction. Physical stimuli sensed by cells are transmitted through intracellular signal transduction pathways resulting in altered physiological responses or pathological conditions. Emerging evidence from experimental studies indicate that β1-integrin and the angiotensin II type I (AT1) receptor play critical roles as mechanosensors in the regulation of heart contraction, growth and leading to heart failure. Integrin link the extracellular matrix and the intracellular cytoskeleton to initiate the mechanical signalling, whereas, the AT1 receptor could be activated by mechanical stress through an angiotensin-II-independent mechanism. Recent studies show that both Integrin and AT1 receptor and their downstream signalling factors including MAPKs, AKT, FAK, ILK and GTPase regulate heart function in cardiac myocytes. In this review we describe the role of mechanical sensors residing within the plasma membrane, mechanical sensor induced downstream signalling factors and its potential roles in cardiac contraction and growth.
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Affiliation(s)
- David E Dostal
- Central Texas Veterans Health Care System, Temple, Texas, USA ; Division of Molecular Cardiology, Cardiovascular Research Institute, Texas A&M University Health Science Centre, College of Medicine, Temple, Texas, USA
| | - Hao Feng
- Division of Molecular Cardiology, Cardiovascular Research Institute, Texas A&M University Health Science Centre, College of Medicine, Temple, Texas, USA
| | - Damir Nizamutdinov
- Division of Molecular Cardiology, Cardiovascular Research Institute, Texas A&M University Health Science Centre, College of Medicine, Temple, Texas, USA
| | - Honey B Golden
- Division of Molecular Cardiology, Cardiovascular Research Institute, Texas A&M University Health Science Centre, College of Medicine, Temple, Texas, USA
| | - Syeda H Afroze
- Scott & White Healthcare - Digestive Disease Research Centre, Temple, Texas, USA
| | - Joseph D Dostal
- Division of Molecular Cardiology, Cardiovascular Research Institute, Texas A&M University Health Science Centre, College of Medicine, Temple, Texas, USA
| | - John C Jacob
- Division of Molecular Cardiology, Cardiovascular Research Institute, Texas A&M University Health Science Centre, College of Medicine, Temple, Texas, USA
| | - Donald M Foster
- Central Texas Veterans Health Care System, Temple, Texas, USA
| | - Carl Tong
- Systems Biology and Translational Medicine, the Texas A&M University Health Science Centre, College of Medicine, Temple, Texas, USA
| | - Shannon Glaser
- Central Texas Veterans Health Care System, Temple, Texas, USA ; Scott & White Healthcare - Digestive Disease Research Centre, Temple, Texas, USA
| | - Fnu Gerilechaogetu
- Division of Molecular Cardiology, Cardiovascular Research Institute, Texas A&M University Health Science Centre, College of Medicine, Temple, Texas, USA
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Dormishian M, Turkeri G, Urayama K, Nguyen TL, Boulberdaa M, Messaddeq N, Renault G, Henrion D, Nebigil CG. Prokineticin receptor-1 is a new regulator of endothelial insulin uptake and capillary formation to control insulin sensitivity and cardiovascular and kidney functions. J Am Heart Assoc 2013; 2:e000411. [PMID: 24152983 PMCID: PMC3835255 DOI: 10.1161/jaha.113.000411] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Background Reciprocal relationships between endothelial dysfunction and insulin resistance result in a vicious cycle of cardiovascular, renal, and metabolic disorders. The mechanisms underlying these impairments are unclear. The peptide hormones prokineticins exert their angiogenic function via prokineticin receptor‐1 (PKR1). We explored the extent to which endothelial PKR1 contributes to expansion of capillary network and the transcapillary passage of insulin into the heart, kidney, and adipose tissues, regulating organ functions and metabolism in a specific mice model. Methods and Results By combining cellular studies and studies in endothelium‐specific loss‐of‐function mouse model (ec‐PKR1−/−), we showed that a genetically induced PKR1 loss in the endothelial cells causes the impaired capillary formation and transendothelial insulin delivery, leading to insulin resistance and cardiovascular and renal disorders. Impaired insulin delivery in endothelial cells accompanied with defective expression and activation of endothelial nitric oxide synthase in the ec‐PKR1−/− aorta, consequently diminishing endothelium‐dependent relaxation. Despite having a lean body phenotype, ec‐PKR1−/− mice exhibited polyphagia, polydipsia, polyurinemia, and hyperinsulinemia, which are reminiscent of human lipodystrophy. High plasma free fatty acid levels and low leptin levels further contribute to the development of insulin resistance at the later age. Peripheral insulin resistance and ectopic lipid accumulation in mutant skeletal muscle, heart, and kidneys were accompanied by impaired insulin‐mediated Akt signaling in these organs. The ec‐PKR1−/− mice displayed myocardial fibrosis, low levels of capillary formation, and high rates of apoptosis, leading to diastolic dysfunction. Compact fibrotic glomeruli and high levels of phosphate excretion were found in mutant kidneys. PKR1 restoration in ec‐PKR1−/− mice reversed the decrease in capillary recruitment and insulin uptake and improved heart and kidney function and insulin resistance. Conclusions We show a novel role for endothelial PKR1 signaling in cardiac, renal, and metabolic functions by regulating transendothelial insulin uptake and endothelial cell proliferation. Targeting endothelial PKR1 may serve as a therapeutic strategy for ameliorating these disorders.
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Affiliation(s)
- Mojdeh Dormishian
- CNRS, Université de Strasbourg, UMR7242, Ecole Supérieure de Biotechnologie de Strasbourg, and Medalis/Labex, Drug Discovery Center, Illkirch, France
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8
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Zhang XQ, Tang R, Li L, Szucsik A, Javan H, Saegusa N, Spitzer KW, Selzman CH. Cardiomyocyte-specific p65 NF-κB deletion protects the injured heart by preservation of calcium handling. Am J Physiol Heart Circ Physiol 2013; 305:H1089-97. [PMID: 23913709 DOI: 10.1152/ajpheart.00067.2013] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
NF-κB is a well-known transcription factor that is intimately involved with inflammation and immunity. We have previously shown that NF-κB promotes inflammatory events and mediates adverse cardiac remodeling following ischemia reperfusion (I/R). Conversely, others have pointed to the beneficial influence of NF-κB in I/R injury related to its anti-apoptotic effects. Understanding the seemingly disparate influence of manipulating NF-κB is hindered, in part, by current approaches that only indirectly interfere with the function of its most transcriptionally active unit, p65 NF-κB. Mice were generated with cardiomyocyte-specific deletion of p65 NF-κB. Phenotypically, these mice and their hearts appeared normal. Basal and stimulated p65 expression were significantly reduced in whole hearts and completely ablated in isolated cardiomyocytes. When compared with wild-type mice, transgenic animals were protected from both global I/R by Langendorff as well as regional I/R by coronary ligation and release. The protected, transgenic hearts had less cytokine activity and decreased apoptosis. Furthermore, p65 ablation was associated with enhanced calcium reuptake by the sarcoplasmic reticulum. This influence on calcium handling was related to increased expression of phosphorylated phospholamban in conditional p65 null mice. In conclusion, cardiomyocyte-specific deletion of the most active, canonical NF-κB subunit affords cardioprotection to both global and regional I/R injury. The beneficial effects of NF-κB inhibition are related, in part, to modulation of intracellular calcium homeostasis.
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Affiliation(s)
- Xiu Q Zhang
- Division of Cardiothoracic Surgery, Department of Surgery, University of Utah, Salt Lake City, Utah
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9
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Ozturk N, Yaras N, Ozmen A, Ozdemir S. Long-term administration of rosuvastatin prevents contractile and electrical remodelling of diabetic rat heart. J Bioenerg Biomembr 2013; 45:343-52. [PMID: 23640692 DOI: 10.1007/s10863-013-9514-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2013] [Accepted: 04/19/2013] [Indexed: 01/09/2023]
Abstract
In recent years, many findings have been presented about the potential benefit of statin therapy on diabetes-induced cardiovascular complications. Cardioprotective effects of statins were suggested to be mediated at least in part through inhibition of small GTPases, particularly those of the Rho family. The present study was designed to examine whether rosuvastatin can improve electrical remodeling and contractile dysfunction in type 1 diabetic rat heart via modulation of RhoA pathway. Type 1 diabetes was induced by single dose injection of STZ (50 mg/kg). One week after injection rosuvastatin (10 mg/kg/day) and sham treatment was given for 5 weeks in the diabetic rats, as well as in control groups. Shortening and Ca²⁺ transients were recorded in myocytes loaded with Fura2-AM. Membrane currents and Ca²⁺ transients were measured synchronously via whole-cell patch clamping. In untreated diabetic rats, relaxation of shortening and decay of the matched Ca²⁺ transients were prolonged. Fractional shortening and Ca²⁺ transients were also decreased. Rosuvastatin treatment reversed those changes. I(CaL) density did not change in either group but rosuvastatin recovered the loss of sarcoplasmic reticulum Ca²⁺ and Na⁺/Ca²⁺ exchange as evidenced from amplitude and decay of caffeine-induced Ca²⁺ transients, peak INCX and calculated sarcoplasmic reticulum Ca²⁺ content. Diabetes-induced attenuation of I(to) and I(sus) was also reversed, whilst I(K1) was unchanged in diabetes and unaffected by treatment. Rosuvastatin prevented the diabetes-induced increase in RhoA expression. Plasma cholesterol and triglyceride levels were higher in diabetic rats, but rosuvastatin reduced only the latter. In conclusion, HMG-CoA reductase inhibitor rosuvastatin can prevent diabetes-induced electrical and functional remodeling of heart due to inhibition of RhoA signalling rather than reduction of cholesterol level.
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Affiliation(s)
- Nihal Ozturk
- Department of Biophysics, Akdeniz University Faculty of Medicine, Antalya, Turkey
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Chen Y, Zhao J, Du J, Xu G, Tang C, Geng B. Hydrogen sulfide regulates cardiac sarcoplasmic reticulum Ca(2+) uptake via K(ATP) channel and PI3K/Akt pathway. Life Sci 2012; 91:271-8. [PMID: 22884808 DOI: 10.1016/j.lfs.2012.07.026] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2012] [Revised: 07/05/2012] [Accepted: 07/13/2012] [Indexed: 12/18/2022]
Abstract
AIMS To investigate the effects of hydrogen sulfide (H(2)S) on calcium uptake activity of the rat cardiac sarcoplasmic reticulum (SR) and possible signaling. MAIN METHODS Crude SR was isolated after treatment with H(2)S, then SR Ca(2+) uptake and SR Ca(2+)-ATPase (SERCA) activity was measured by the isotopic tracer method. The possible roles of the K(ATP) channel and PI3K/Akt and SR-membrane protein phospholamban (PLB) pathway were analyzed by specific blockers, and target protein activation was assayed by measuring protein phosphorylation. KEY FINDINGS Exogenous H(2)S lowered Ca(2+) uptake into the SR time or concentration dependently, which was associated with decreased SERCA activity. Inhibiting endogenous H(2)S production by DL-propargylglycine increased SR Ca(2+) uptake and SERCA activity. H(2)S inhibition of PLB phosphorylation was through SERCA activity and was reversed by two PI3K inhibitors, wortmannin and LY294002. Glibenclamide (a K(ATP) channel blocker) blocked the inhibitory effects of H(2)S on PLB and Akt phosphorylation. Pinacidil (a K(ATP) channel opener) reduced the phosphorylation of PLB and reversed the effects of DL-propargylglycine. H(2)S preconditioning increased PLB phosphorylation but did not affect SERCA activity. SIGNIFICANCE Endogenous H(2)S transiently and reversibly inhibits SR Ca(2+) uptake in rat heart SR because of downregulated SERCA activity associated with PLB phosphorylation by the PI3K/Akt or K(ATP) channel. The transient negative regulation of SR Ca(2+) uptake and the L-type Ca(2+) channel contributes to Ca(2+) cycle homeostasis, which might be an important molecular mechanism in ischemic diseases.
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Affiliation(s)
- Yu Chen
- Department of Physiology and Pathophysiology, School of Basic Medical Science, Peking University, PR China
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Aydemir M, Ozturk N, Dogan S, Aslan M, Olgar Y, Ozdemir S. Sodium tungstate administration ameliorated diabetes-induced electrical and contractile remodeling of rat heart without normalization of hyperglycemia. Biol Trace Elem Res 2012; 148:216-23. [PMID: 22351103 DOI: 10.1007/s12011-012-9350-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2011] [Accepted: 01/26/2012] [Indexed: 01/01/2023]
Abstract
Recently, sodium tungstate was suggested to improve cardiac performance of diabetic rats in perfused hearts based on its insulinomimetic activity. In this study, we aimed to investigate the cellular and molecular mechanisms underlying this beneficial effect of sodium tungstate. Tungstate was administered (100 mg/kg/day) to diabetic and control rats intragastrically for 6 weeks. Blood glucose levels increased, whereas body weight, heart weight and plasma insulin levels decreased significantly in diabetic animals. Interestingly, none of these parameters was changed by tungstate treatment. On the other hand, fractional shortening and accompanying intracellular Ca(2+) [Ca(2+)](i) transients of isolated ventricular myocytes were measured, and sodium tungstate was found to improve the peak shortening and the amplitude of [Ca(2+)](i) transients in diabetic cardiomyocytes. Potassium and L-type Ca(2+) currents were also recorded in isolated ventricular cells. Significant restoration of suppressed I (to) and I (ss) was achieved by tungstate administration. Nevertheless, L-type calcium currents did not change either in untreated or treated diabetic rats. Tissue biochemical parameters including TBARS, protein carbonyl content, xanthine oxidase (XO) and xanthine dehydogenase (XDH) were also determined, and diabetes revealed a marked increase in TBARS and carbonyl content which were decreased significantly by tungstate treatment. Conversely, although XO and XDH activities didn't change in untreated diabetic rats, a remarkable but insignificant decrease was detected in treated animals. In conclusion, tungstate treatment improved diabetes-induced contractile abnormalities via restoration of dysregulated [Ca(2+)](i) and altered ionic currents. This beneficial effect is due to antioxidant property of sodium tungstate rather than normalization of hyperglycemia.
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Affiliation(s)
- Mustafa Aydemir
- Faculty of Medicine, Department of Biophysics, Akdeniz University, Antalya, Turkey
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Sussman MA, Völkers M, Fischer K, Bailey B, Cottage CT, Din S, Gude N, Avitabile D, Alvarez R, Sundararaman B, Quijada P, Mason M, Konstandin MH, Malhowski A, Cheng Z, Khan M, McGregor M. Myocardial AKT: the omnipresent nexus. Physiol Rev 2011; 91:1023-70. [PMID: 21742795 PMCID: PMC3674828 DOI: 10.1152/physrev.00024.2010] [Citation(s) in RCA: 180] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
One of the greatest examples of integrated signal transduction is revealed by examination of effects mediated by AKT kinase in myocardial biology. Positioned at the intersection of multiple afferent and efferent signals, AKT exemplifies a molecular sensing node that coordinates dynamic responses of the cell in literally every aspect of biological responses. The balanced and nuanced nature of homeostatic signaling is particularly essential within the myocardial context, where regulation of survival, energy production, contractility, and response to pathological stress all flow through the nexus of AKT activation or repression. Equally important, the loss of regulated AKT activity is primarily the cause or consequence of pathological conditions leading to remodeling of the heart and eventual decompensation. This review presents an overview compendium of the complex world of myocardial AKT biology gleaned from more than a decade of research. Summarization of the widespread influence that AKT exerts upon myocardial responses leaves no doubt that the participation of AKT in molecular signaling will need to be reckoned with as a seemingly omnipresent regulator of myocardial molecular biological responses.
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Affiliation(s)
- Mark A Sussman
- Department of Biology, San Diego State University, SDSU Heart Institute, San Diego, California 92182, USA.
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Ma H, Li SY, Xu P, Babcock SA, Dolence EK, Brownlee M, Li J, Ren J. Advanced glycation endproduct (AGE) accumulation and AGE receptor (RAGE) up-regulation contribute to the onset of diabetic cardiomyopathy. J Cell Mol Med 2010; 13:1751-1764. [PMID: 19602045 PMCID: PMC2829341 DOI: 10.1111/j.1582-4934.2008.00547.x] [Citation(s) in RCA: 135] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Diabetic cardiomyopathy is manifested by compromised systolic and diastolic function. This study was designed to examine the role of advanced glycation endproduct (AGE) and AGE receptor (RAGE) in diabetic cardiomyopathy. Heart function was assessed in isolated control and streptozotocin-induced diabetic hearts following in vivo RAGE gene knockdown using RNA interference. Cardiomyocyte mechanical properties were evaluated including peak shortening (PS), time-to-PS (TPS) and time-to-90% relengthening (TR(90)). RAGE was assayed by RT-PCR and immunoblot. Diabetes significantly enhanced cardiac MG, AGE and RAGE levels accompanied with colocalization of AGE and RAGE in cardiomyocytes. Diabetes-elicited increase in RAGE was inhibited by in vivo siRNA interference. The AGE formation inhibitor benfotiamine significantly attenuated diabetes-induced elevation in MG, AGE, RAGE and collagen cross-linking without affecting hypertriglyceridaemia and hypercholesterolaemia in diabetes. Diabetes markedly decreased LV contractility, as evidenced by reduced +/-dP/dt and LV developed pressure (LVDP), which were protected by RAGE gene knockdown. In addition, MG-derived AGE (MG-AGE) up-regulated cardiac RAGE mRNA and triggered cardiomyocyte contractile dysfunction reminiscent of diabetic cardiomyopathy. The MG-AGE-elicited prolongation of TPS and TR(90) was ablated by an anti-RAGE antibody in cardiomyocytes. Interestingly, MG-AGE-induced cardiomyocyte dysfunction was associated with mitochondrial membrane potential (MMP) depolarization and reduced GSK-3beta inactivation in control cardiomyocytes, similar to those from in vivo diabetes. Treatment with siRNA-RAGE ablated diabetes-induced MMP depolarization and GSK-3beta inactivation. Collectively, our result implicated a role of AGE-RAGE in the pathogenesis of diabetic cardiomyopathy.
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Affiliation(s)
- Heng Ma
- Department of Physiology, Fourth Military Medical University, Xi'an, China.,Division of Pharmaceutical Sciences & Center for Cardiovascular Research and Alternative Medicine, University of Wyoming, Laramie, WY, USA
| | - Shi-Yan Li
- Division of Pharmaceutical Sciences & Center for Cardiovascular Research and Alternative Medicine, University of Wyoming, Laramie, WY, USA
| | - Peisheng Xu
- Division of Pharmaceutical Sciences & Center for Cardiovascular Research and Alternative Medicine, University of Wyoming, Laramie, WY, USA
| | - Sara A Babcock
- Division of Pharmaceutical Sciences & Center for Cardiovascular Research and Alternative Medicine, University of Wyoming, Laramie, WY, USA
| | - E Kurt Dolence
- Division of Pharmaceutical Sciences & Center for Cardiovascular Research and Alternative Medicine, University of Wyoming, Laramie, WY, USA
| | - Michael Brownlee
- Diabetes Research Center, Albert Einstein College of Medicine, New York, NY, USA
| | - Ji Li
- Division of Pharmaceutical Sciences & Center for Cardiovascular Research and Alternative Medicine, University of Wyoming, Laramie, WY, USA
| | - Jun Ren
- Department of Physiology, Fourth Military Medical University, Xi'an, China.,Division of Pharmaceutical Sciences & Center for Cardiovascular Research and Alternative Medicine, University of Wyoming, Laramie, WY, USA
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Interaction between age and obesity on cardiomyocyte contractile function: role of leptin and stress signaling. PLoS One 2010; 5:e10085. [PMID: 20396382 PMCID: PMC2852499 DOI: 10.1371/journal.pone.0010085] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2009] [Accepted: 03/17/2010] [Indexed: 12/31/2022] Open
Abstract
Objectives This study was designed to evaluate the interaction between aging and obesity
on cardiac contractile and intracellular Ca2+
properties. Methods Cardiomyocytes from young (4-mo) and aging (12- and 18-mo) male lean and the
leptin deficient ob/ob obese mice were treated with leptin
(0.5, 1.0 and 50 nM) for 4 hrs in vitro. High fat diet
(45% calorie from fat) and the leptin receptor mutant
db/db obesity models at young and older age were used
for comparison. Cardiomyocyte contractile and intracellular
Ca2+ properties were evaluated including peak
shortening (PS), maximal velocity of shortening/relengthening (±
dL/dt), time-to-PS (TPS), time-to-90% relengthening
(TR90), intracellular Ca2+ levels and
decay. O2− levels were measured by
dihydroethidium fluorescence. Results Our results revealed reduced survival in ob/ob mice. Aging
and obesity reduced PS, ± dL/dt, intracellular
Ca2+ rise, prolonged TR90 and
intracellular Ca2+ decay, enhanced
O2− production and
p47phox expression
without an additive effect of the two, with the exception of intracellular
Ca2+ rise. Western blot analysis exhibited reduced
Ob-R expression and STAT-3 phosphorylation in both young and aging
ob/ob mice, which was restored by leptin. Aging and
obesity reduced phosphorylation of Akt, eNOS and p38 while promoting pJNK
and pIκB. Low levels of leptin reconciled contractile, intracellular
Ca2+ and cell signaling defects as well as
O2− production and
p47phox upregulation in
young but not aging ob/ob mice. High level of leptin (50
nM) compromised contractile and intracellular Ca2+
response as well as O2− production and
stress signaling in all groups. High fat diet-induced and
db/db obesity displayed somewhat comparable
aging-induced mechanical but not leptin response. Conclusions Taken together, our data suggest that aging and obesity compromise cardiac
contractile function possibly via phosphorylation of Akt, eNOS and stress
signaling-associated O2− release.
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Abstract
Diabetic cardiomyopathy increases the risk of heart failure in individuals with diabetes, independently of co-existing coronary artery disease and hypertension. The underlying mechanisms for this cardiac complication are incompletely understood. Research on rodent models of type 1 and type 2 diabetes, and the use of genetic engineering techniques in mice, have greatly advanced our understanding of the molecular mechanisms responsible for human diabetic cardiomyopathy. The adaptation of experimental techniques for the investigation of cardiac physiology in mice now allows comprehensive characterization of these models. The focus of the present review will be to discuss selected rodent models that have proven to be useful in studying the underlying mechanisms of human diabetic cardiomyopathy, and to provide an overview of the characteristics of these models for the growing number of investigators who seek to understand the pathology of diabetes-related heart disease.
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Affiliation(s)
- Heiko Bugger
- Division of Endocrinology, Metabolism and Diabetes, and Program in Molecular Medicine, University of Utah School of Medicine, Salt Lake City, UT 84132, USA
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16
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Abstract
Diabetic heart disease contributes to the high mortality in diabetics, although effective clinical management is lacking. The protease inhibitor 5-[5-(2-nitrophenyl) furfuryliodine]-1,3-diphenyl-2-thiobarbituric acid (UCF-101) was reported to protect the hearts against ischemic injury. This study examined the role of UCF-101 on streptozotocin (STZ)-induced diabetic heart defect. Vehicle or UCF-101 was administrated to STZ diabetic mice, and cardiomyocyte mechanical properties were analyzed. UCF-101 reduced STZ-induced hyperglycemia and alleviated STZ-induced aberration in cardiomyocyte contractile mechanics. Diabetes dramatically decreased AMPK phosphorylation at Thr(172) of catalytic alpha-subunit, which was restored by UCF-101. Neither diabetes nor UCF-101 affected the expression of HtrA2/Omi and XIAP or caspase-3 activity. The AMPK activator resveratrol mimicked the UCF-101-induced beneficial effect against diabetic cardiac dysfunction. Mechanical properties in cardiomyocytes from the AMPK-kinase-dead (KD) mice displayed markedly impaired contractile function reminiscent of diabetes. STZ injection in AMPK-KD mice failed to elicit any additional cardiomyocyte contractile defect. UCF-101 significantly downregulated the AMPK-degrading enzymes PP2A and PP2C, the effect of which was mimicked by resveratrol. Taken together, these results indicate that UCF-101 protects against STZ-induced cardiac dysfunction, possibly through AMPK signaling.
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Affiliation(s)
- Qun Li
- Division of Pharmaceutical Sciences, University of Wyoming, Laramie, WY 82071, USA
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17
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Bhuiyan MS, Fukunaga K. Cardioprotection by vanadium compounds targeting Akt-mediated signaling. J Pharmacol Sci 2009; 110:1-13. [PMID: 19423951 DOI: 10.1254/jphs.09r01cr] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Treatment with inorganic and organic compounds of vanadium has been shown to exert a wide range of cardioprotective effects in myocardial ischemia/reperfusion-induced injury, myocardial hypertrophy, hypertension, and vascular diseases. Furthermore, administration of vanadium compounds improves cardiac performance and smooth muscle cell contractility and modulates blood pressure in various models of hypertension. Like other vanadium compounds, we documented bis(1-oxy-2-pyridinethiolato) oxovanadium (IV) [VO(OPT)] as a potent cardioprotective agent to elicit cardiac functional recovery in myocardial infarction and pressure overload-induced hypertrophy. Vanadium compounds activate Akt signaling through inhibition of protein tyrosine phosphatases, thereby eliciting cardioprotection in myocardial ischemia/reperfusion-induced injury and myocardial hypertrophy. Vanadium compounds also promote cardiac functional recovery by stimulation of glucose transport in diabetic heart. We here discuss the current understanding of mechanisms underlying vanadium compound-induced cardioprotection and propose a novel therapeutic strategy targeting for Akt signaling to rescue cardiomyocytes from heart failure.
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18
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Abstract
The diverse effects mediated by PI3K/PTEN (phosphoinositide 3-kinase/phosphatase and tensin homologue deleted on chromosome 10) signalling in the heart clearly support an important biological and pathophysiological role for this signalling cascade. PI3Ks are a family of evolutionarily conserved lipid kinases that mediate many cellular responses to physiological and pathophysiological stimuli. Class I PI3K can be activated by either receptor tyrosine kinase/cytokine receptor activation (class IA) or G-protein-coupled receptors (class IB), leading to the generation of phosphatidyl inositol (3,4,5)P3 and recruitment and activation of Akt/protein kinase B, 3'-phosphoinositide-dependent kinase-1 (PDK1), or monomeric G-proteins, and phosphorylation of a wide range of downstream targets including glycogen synthase kinase 3beta (GSK3beta), mTOR (mammalian target of rapamycin), p70S6 kinase, endothelial nitric oxide synthase, and several anti-apoptotic effectors. Class IA (PI3Kalpha, beta, and delta) and class IB (PI3Kgamma) PI3Ks mediate distinct phenotypes in the heart under negative control by the 3'-lipid phosphatase PTEN, which dephosphorylates PtdIns(3,4,5)P3 to generate PtdIns(4,5)P2. PI3Kalpha, PI3Kgamma, and PTEN are expressed in cardiomyocytes, fibroblasts, endothelial cells, and vascular smooth muscle cells, where they modulate cell survival, hypertrophy, contractility, metabolism, and mechanotransduction. The PI3K/PTEN signalling pathways are involved in a wide variety of diseases including myocardial hypertrophy and contractility, heart failure, and preconditioning. In this review, we discuss the signalling pathways mediated by PI3K class I isoforms and PTEN and their roles in cardiac structure and function.
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Affiliation(s)
- Gavin Y Oudit
- Division of Cardiology, Department of Medicine, Mazankowski Alberta Heart Institute, University of Alberta, Edmonton, Alberta, Canada T6G 2B7.
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19
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Bhuiyan MS, Shioda N, Fukunaga K. Targeting protein kinase B/Akt signaling with vanadium compounds for cardioprotection. Expert Opin Ther Targets 2008; 12:1217-27. [PMID: 18781821 DOI: 10.1517/14728222.12.10.1217] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
BACKGROUND Akt is an important signaling molecule that modulates many cellular processes such as cell growth, survival and metabolism. Akt activation has been proposed as a potential strategy for increasing cardiomyocyte survival following ischemia. OBJECTIVES Vanadium compounds activate Akt signaling through inhibition of protein tyrosine phosphatases, thereby eliciting cardioprotection in myocardial ischemia/reperfusion-induced injury along with cardiac functional recovery. Like other vanadium compounds, we documented bis(1-oxy-2-pyridinethiolato) oxovanadium (IV) as a potent cytoprotective agent on myocardial infarction and elicited cardiac functional recovery through activation of Akt signaling pathway. RESULTS/CONCLUSION The ability of vanadium compounds to activate Akt signaling pathways are responsible for their ability to modulate cardiovascular functions and is probably beneficial as a cardioprotective drug in subjects undergoing reperfusion therapy following myocardial infarction.
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Affiliation(s)
- Md Shenuarin Bhuiyan
- Graduate School of Pharmaceutical Sciences, Department of Pharmacology, Tohoku University, Aramaki-Aoba Aoba-ku, Sendai 980-8578, Japan
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20
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Ren J, Duan J, Thomas DP, Yang X, Sreejayan N, Sowers JR, Leri A, Kajstura J, Gao F, Anversa P. IGF-I alleviates diabetes-induced RhoA activation, eNOS uncoupling, and myocardial dysfunction. Am J Physiol Regul Integr Comp Physiol 2008; 294:R793-802. [PMID: 18199585 DOI: 10.1152/ajpregu.00713.2007] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
IGF-I rescues diabetic heart defects and oxidative stress, although the underlying mechanism of action remains poorly understood. This study was designed to delineate the beneficial effects of IGF-I with a focus on RhoA, Akt, and eNOS coupling. Echocardiography was performed in normal or diabetic Friend Virus-B type (FVB) and IGF-I transgenic mice. Cardiomyocyte contractile properties were evaluated using peak shortening (PS), time-to-90% relengthening (TR90), and intracellular Ca2+ rise and decay. Diabetes reduced fraction shortening, PS, and intracellular Ca2+; it increased chamber size, prolonged TR90, and intracellular Ca2+ decay. Levels of RhoA mRNA, active RhoA, and O2(-) were elevated, whereas nitric oxide (NO) levels were reduced in diabetes. Diabetes-induced O2(-) accumulation was ablated by the NO synthase (NOS) inhibitor nitro-L-arginine methyl ester (L-NAME), indicating endothelial NOS (eNOS) uncoupling, all of which except heart size were negated by IGF-I. The IGF-I-elicited beneficial effects were mimicked by the Rho kinase inhibitor Y27632 and BH4. Diabetes depressed expression of Kv1.2 and dihydrofolate reductase (DHFR), increased beta-myosin heavy-chain expression, stimulated p38 MAPK, and reduced levels of total Akt and phosphorylated Akt/eNOS, all of which with the exception of myosin heavy chain were attenuated by IGF-I. In addition, Y27632 and the eNOS coupler folate abrogated glucose toxicity-induced PS decline, TR90 prolongation, while it increased O2(-) and decreased NO and Kv1.2 levels. The DHFR inhibitor methotrexate impaired myocyte function, NO/O2(-) balance, and rescued Y27632-induced cardiac protection. These results revealed that IGF-I benefits diabetic hearts via Rho inhibition and antagonism of diabetes-induced decrease in pAkt, eNOS uncoupling, and K+ channel expression.
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Affiliation(s)
- Jun Ren
- School of Pharmacy, University of Wyoming, Laramie, WY 82071, USA.
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21
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Song Y, Du Y, Prabhu SD, Epstein PN. Diabetic Cardiomyopathy in OVE26 Mice Shows Mitochondrial ROS Production and Divergence Between In Vivo and In Vitro Contractility. Rev Diabet Stud 2007; 4:159-68. [PMID: 18084673 PMCID: PMC2174063 DOI: 10.1900/rds.2007.4.159] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Many diabetic patients suffer from a cardiomyopathy that cannot be explained solely by poor coronary perfusion. This cardiomyopathy may be due to either organ-based damage like fibrosis, or to direct damage to cardiomyocytes. Mitochondrial-derived reactive oxygen species (ROS) have been proposed to contribute to this cardiomyopathy. To address these questions, we used the OVE26 mouse model of severe type 1 diabetes to measure contractility in isolated cardiomyocytes by edge detection and in vivo with echocardiography. We also assessed the source of ROS generation using both a general and a mitochondrial specific indicator. When contractility was assayed in freshly isolated myocytes, contraction was much stronger in control myocytes. However, contractility of normal myocytes became weaker during 24 hours of in vitro culture. In contrast, contractility of diabetic OVE26 myocytes remains stable during culture. Echocardiography revealed normal or hyperdynamic function in OVE26 hearts under basal conditions but with a sharply reduced response to isoproterenol, a beta-adrenergic agonist. For ROS generation, we found that ROS production in diabetic myocytes was elevated after exposure to either high glucose or angiotensin II (AngII). Superoxide detection with the mitochondrial sensor MitoSOX Red confirmed that mitochondria are a major source of ROS generation in diabetic myocytes. These results show that contractile deficits in OVE26 diabetic hearts are due primarily to cardiomyocyte impairment and that ROS from mitochondria are a cause of that impairment.
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Affiliation(s)
- Ye Song
- Department of Pediatrics, University of Louisville and Louisville VAMC, Louisville, Kentucky, USA
| | - Yibo Du
- Department of Pediatrics, University of Louisville and Louisville VAMC, Louisville, Kentucky, USA
| | - Sumanth D. Prabhu
- Department of Medicine/Cardiology, University of Louisville and Louisville VAMC, Louisville, Kentucky, USA
| | - Paul N. Epstein
- Department of Pediatrics, University of Louisville and Louisville VAMC, Louisville, Kentucky, USA
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22
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Dong F, Yang X, Sreejayan N, Ren J. Chromium (D-phenylalanine)3 improves obesity-induced cardiac contractile defect in ob/ob mice. Obesity (Silver Spring) 2007; 15:2699-711. [PMID: 18070761 DOI: 10.1038/oby.2007.322] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
OBJECTIVE Low-molecular weight chromium compounds, such as chromium picolinate [Cr(pic)(3)], improve insulin sensitivity, although toxicity is a concern. We synthesized a novel chromium complex, chromium (d-phenylalanine)(3) [Cr(d-phe)(3)], in an attempt to improve insulin sensitivity with reduced toxicity. The aim of this study was to compare the two chromium compounds on cardiac contractile function in ob/ob obese mice. RESEARCH METHODS AND PROCEDURES C57BL lean and ob/ob obese mice were randomly divided into three groups: H(2)O, Cr(d-phe)(3), or Cr(pic)(3) (45 mug/kg per day orally for 6 months). RESULTS The glucose tolerance test displayed improved glucose clearance by Cr(d-phe)(3) but not Cr(pic)(3). Myocytes from ob/ob mice exhibited depressed peak shortening (PS) and maximal velocity of shortening/relengthening (+/-dL/dt), prolonged time-to-PS and time-to-90% relengthening (TR90), reduced electrically stimulated rise in intracellular Ca(2+) (Deltafura-2 fluorescence intensity), and slowed intracellular Ca(2+) decay. Although a 3-month Cr(d-phe)(3) treatment for a separate group of ob/ob and lean 2-month-old mice only rectified reduced +/-dL/dt in ob/ob mice, all mechanical and intracellular Ca(2+) abnormalities were significantly attenuated or ablated by 6 months of Cr(d-phe)(3) but not Cr(pic)(3) treatment (except TR90). Sarco(endo)plasmic reticulum Ca(2+) ATPase activity and Na(+)-Ca(2+) exchanger expression were depressed in ob/ob mice, which were reversed by both Cr(d-phe)(3) and Cr(pic)(3), with a more pronounced effect from Cr(d-phe)(3). Cr(d-phe)(3) corrected reduced insulin-stimulated glucose uptake and improved basal phosphorylation of Akt and insulin receptor, as well as insulin-stimulated phosphorylation of Akt and insulin receptor in ob/ob myocytes. Heart homogenates from ob/ob mice had enhanced oxidative stress and protein carbonyl formation compared with the lean group, which were attenuated by both Cr(d-phe)(3) and Cr(pic)(3). DISCUSSION Our data suggest that the new Cr(d-phe)(3) compound possesses better cardio-protective and insulin-sensitizing properties against obesity.
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Affiliation(s)
- Feng Dong
- Center for Cardiovascular Research and Alternative Medicine and Division of Pharmaceutical Sciences, University of Wyoming, Laramie, Wyoming 82071, USA
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23
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Stratton MS, Yang X, Sreejayan N, Ren J. Impact of Insulin-like Growth Factor-I on Migration, Proliferation and Akt-ERK Signaling in Early and Late-passages of Vascular Smooth Muscle Cells. Cardiovasc Toxicol 2007; 7:273-81. [DOI: 10.1007/s12012-007-9006-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/28/2007] [Accepted: 10/09/2007] [Indexed: 10/22/2022]
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24
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Turdi S, Li Q, Lopez FL, Ren J. Catalase alleviates cardiomyocyte dysfunction in diabetes: role of Akt, Forkhead transcriptional factor and silent information regulator 2. Life Sci 2007; 81:895-905. [PMID: 17765928 DOI: 10.1016/j.lfs.2007.07.029] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2007] [Revised: 06/07/2007] [Accepted: 07/17/2007] [Indexed: 11/17/2022]
Abstract
Oxidative stress has been speculated to play an essential role in diabetic cardiomyopathy. This study was designed to examine the effect of the antioxidant catalase on diabetes-induced cardiomyocyte dysfunction and the cellular mechanisms involved. Adult wild-type (FVB) and transgenic mice with cardiac-specific overexpression of catalase were made diabetic by a single injection of streptozotocin (STZ, 220 mg/kg; i.p., maintained for two weeks). Cardiomyocyte contractile properties were evaluated including peak shortening (PS), time-to-PS (TPS), time-to-relengthening (TR(90)), maximal velocity of shortening/relengthening (+/-dL/dt), intracellular Ca(2+) level and decay rate. STZ depressed -dL/dt, prolonged TPS and TR(90), elevated resting intracellular Ca(2+) level and reduced intracellular Ca(2+) decay in FVB myocytes. While catalase exhibited little effect on contractile and intracellular Ca(2+) properties in control myocytes, it negated diabetes-induced cardiomyocyte mechanical abnormalities. Diabetic myocytes exhibited enhanced levels of reactive oxygen species and apoptosis, which were alleviated by catalase. Western blot analysis revealed that diabetes reduced Akt phosphorylation, enhanced the silent information regulator 2 (Sirt2), and upregulated Forkhead transcriptional factor Foxo3a as well as glycogen synthase kinase-3beta (GSK-3beta) and pGSK-3beta. While catalase itself exhibited little effect on these proteins or their phosphorylation (with the exception of Sirt2), it significantly attenuated diabetes-induced alteration in pAkt, Foxo3a and Sirt2 without affecting GSK-3beta. Inhibition of Sirt2 using splitomicin impaired cardiomyocyte contractile function (reduced PS, +/-dL/dt, prolonged TPS and TR(90)). In summary, our data suggest potential roles of Akt, Foxo3a and Sirt2 in the onset of diabetic cardiomyopathy and the therapeutic potential of catalase.
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Affiliation(s)
- Subat Turdi
- Division of Pharmaceutical Sciences & Center for Cardiovascular Research and Alternative Medicine, University of Wyoming, Laramie, WY 82071, USA
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25
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Relling DP, Esberg LB, Johnson WT, Murphy EJ, Carlson EC, Lukaski HC, Saari JT, Ren J. Dietary interaction of high fat and marginal copper deficiency on cardiac contractile function. Obesity (Silver Spring) 2007; 15:1242-57. [PMID: 17495201 DOI: 10.1038/oby.2007.146] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
OBJECTIVE High-fat and marginally copper-deficient diets impair heart function, leading to cardiac hypertrophy, increased lipid droplet volume, and compromised contractile function, resembling lipotoxic cardiac dysfunction. However, the combined effect of the two on cardiac function is unknown. This study was designed to examine the interaction between high-fat and marginally copper-deficient diets on cardiomyocyte contractile function. RESEARCH METHODS AND PROCEDURES Weanling male rats were fed diets incorporating a low- or high-fat diet (10% or 45% of kcal from fat, respectively) with adequate (6 mg/kg) or marginally deficient (1.5 mg/kg) copper content for 12 weeks. Contractile function was determined with an IonOptix system including peak shortening (PS), time-to-PS, time-to-90% relengthening, maximal velocity of shortening/relengthening, and intracellular Ca(2+) ([Ca(2+)](I)) rise and decay. RESULTS Neither dietary treatment affected blood pressure or glucose levels, although the high-fat diet elicited obesity and glucose intolerance. Both diets depressed PS, maximal velocity of shortening/relengthening, and intracellular Ca(2+) ([Ca(2+)](I)) rise and prolonged time-to-90% relengthening and Ca(2+) decay without an additive effect between the two. Ca(2+) sensitivity, apoptosis, lipid peroxidation, nitrosative damage, tissue ceramide, and triglyceride levels were unaffected by either diet or in combination. Phospholamban (PLB) but not sarco(endo)plasmic reticulum Ca(2+)-ATPase was increased by both diets. Endothelial NO synthase was depressed with concurrent treatments. The electron transport chain was unaffected, although mitochondrial aconitase activity was inhibited by the high-fat diet. DISCUSSION These data suggest that high-fat and marginally copper deficient diets impaired cardiomyocyte contractile function and [Ca(2+)](i) homeostasis, possibly through a similar mechanism, without obvious lipotoxicity, nitrosative damage, and apoptosis.
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Affiliation(s)
- David P Relling
- Department of Pharmacology, Physiology, and Therapeutics, University of North Dakota School of Medicine, Grand Forks, North Dakota, USA
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26
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Li Q, Fang CX, Nunn JM, Zhang J, LaCour KH, Ren J. Characterization of cardiomyocyte excitation-contraction coupling in the FVB/N-C57BL/6 intercrossed "chocolate" brown mice. Life Sci 2006; 80:187-92. [PMID: 17014867 DOI: 10.1016/j.lfs.2006.08.038] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2006] [Revised: 08/19/2006] [Accepted: 08/30/2006] [Indexed: 11/22/2022]
Abstract
Mice are extensively used for gene modification research and isolated cardiomyocytes are essential for evaluation of cardiac function without interference from non-myocyte contribution. This study was designed to characterize cardiomyocyte excitation-contraction coupling in FVB/N-C57BL/6 intercrossed brown mice. Mechanical and intracellular Ca(2+) properties were evaluated using an IonOptix softedge system including peak shortening (PS), time-to-PS (TPS), time-to-90% relengthening (TR(90)), maximal velocity of shortening and relengthening (+/- dL/dt), intracellular Ca(2+) rise and decay rate. Resting cell length was longer in age- and gender-matched C57BL/6 and brown mice compared to FVB strain. PS and +/- dL/dt were significantly lower in brown mice compared to FVB/N and C57BL/6 groups. TPS was shortened in C57BL/6 mice and TR(90) was prolonged in brown mice compared to other groups. Resting intracellular Ca(2+) level and single exponential intracellular Ca(2+) decay constant were comparable among all three mouse lines. Rise in intracellular Ca(2+) in response to electrical stimulus was higher in C57BL/6 mouse myocytes whereas bi-exponential intracellular Ca(2+) decay was faster in brown mice. Myocytes from all three groups exhibited similar fashion of reduction in PS in response to increased stimulus frequency. These data suggest that inherent differences in cardiomyocyte excitation-contraction coupling exist between strains, which may warrant caution when comparing data from these mouse lines.
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Affiliation(s)
- Qun Li
- Center for Cardiovascular Research and Alternative Medicine and Division of Pharmaceutical Sciences, University of Wyoming, Laramie, WY 82071, USA
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27
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Dong F, Taylor MM, Samson WK, Ren J. Intermedin (adrenomedullin-2) enhances cardiac contractile function via a protein kinase C- and protein kinase A-dependent pathway in murine ventricular myocytes. J Appl Physiol (1985) 2006; 101:778-84. [PMID: 16763098 DOI: 10.1152/japplphysiol.01631.2005] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Intermedin (IMD), also called adrenomedullin-2, is a 47-amino acid peptide from the calcitonin gene-related peptide (CGRP)/adrenomedullin family of peptides. Recent studies suggest that IMD may participate in the regulation of cardiovascular function and fluid and electrolyte homeostasis. To evaluate the role of IMD on cardiomyocyte contractile function, electrically paced murine ventricular myocytes were acutely exposed to IMD, and the following indexes were determined: peak shortening (PS), time to PS, time-to-90% relengthening, and maximal velocity of shortening and relengthening. Intracellular Ca2+ was assessed using fura 2-AM fluorescent microscopy. Our results revealed that IMD (10 pM to 10 nM) significantly increased PS and maximal velocity of shortening and relengthening in ventricular myocytes, the maximal effect of which (∼46%) was somewhat comparable to those elicited by CGRP (1 nM) and adrenomedullin (100 nM). Exposure of IMD significantly shortened time-to-90% relengthening without affecting time to PS, similar to CGRP and adrenomedullin. IMD also enhanced intracellular Ca2+ release, with a maximal increase of ∼50%, and facilitated the intracellular Ca2+ decay rate. The IMD-induced effects were abolished by the protein kinase C inhibitor chelerythrine (1 μM), downregulation of protein kinase C using phorbol 12-myristate 13-acetate (1 μM), and the protein kinase A inhibitor H89 (1 μM). Our data suggest that IMD acutely augments cardiomyocyte contractile function through, at least in part, a protein kinase C- and protein kinase A-dependent mechanism.
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Affiliation(s)
- Feng Dong
- Division of Pharmaceutical Sciences & Center for Cardiovascular Research and Alternative Medicine, University of Wyoming, Laramie, WY 82071-3375, USA
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28
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Guo KK, Ren J. Cardiac overexpression of alcohol dehydrogenase (ADH) alleviates aging-associated cardiomyocyte contractile dysfunction: role of intracellular Ca2+ cycling proteins. Aging Cell 2006; 5:259-65. [PMID: 16842498 DOI: 10.1111/j.1474-9726.2006.00215.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Aging is a complex biological process with contributions from a wide variety of genes including insulin-like growth factor I and alcohol dehydrogenase (ADH), which decline with advanced age. The goal of this study was to examine if ADH enzyme plays any role in cardiac aging. Ventricular myocytes were isolated from young (2-3 months old) or aged (26-28 months old) male FVB wild-type and cardiac-specific ADH (class I, isozyme type 1) transgenic mice. Mechanical properties were measured using an IonOptix system. Aged FVB myocytes displayed significantly reduced ADH activity compared with young ones, which was restored by the ADH transgene. Compared with young cardiomyocytes, aged FVB myocytes exhibited prolonged relengthening duration and a steaper decline in peak shortening amplitude in response to elevated electrical stimuli. Although ADH transgene itself did not alter mechanical properties in young mice, it rescued aging-associated diastolic dysfunction without affecting dampened contractile response to high stimulus frequency. Immunoblot analysis revealed reduced sarco(endo)plasmic reticulum Ca(2+)-ATPase (SERCA2a) and Na(+)-Ca(2+) exchanger (NCX) levels in conjunction with enhanced phospholamban expression in aged FVB hearts. ADH transgene prevented aging-induced reduction in SERCA2a and NCX without affecting up-regulated phospholamban. Our data suggest that aging is associated with a reduced ADH enzymatic activity and diastolic dysfunction, which may be corrected with cardiac overexpression of the ADH enzyme. Alteration in cardiac Ca(2+) cycling proteins including SERCA2a and NCX may play a role in both pathogenesis of cardiac aging and the beneficial effect of ADH enzyme.
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Affiliation(s)
- Kelly K Guo
- Division of Pharmaceutical Sciences & Center for Cardiovascular Research and Alternative Medicine, University of Wyoming, Laramie, WY 82071, USA
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29
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Cittadini A, Monti MG, Iaccarino G, Di Rella F, Tsichlis PN, Di Gianni A, Strömer H, Sorriento D, Peschle C, Trimarco B, Saccà L, Condorelli G. Adenoviral gene transfer of Akt enhances myocardial contractility and intracellular calcium handling. Gene Ther 2006; 13:8-19. [PMID: 16094411 PMCID: PMC2999753 DOI: 10.1038/sj.gt.3302589] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The serine-threonine kinase Akt/PKB mediates stimuli from different classes of cardiomyocyte receptors, including the growth hormone/insulin like growth factor and the beta-adrenergic receptors. Whereas the growth-promoting and antiapoptotic properties of Akt activation are well established, little is known about the effects of Akt on myocardial contractility, intracellular calcium (Ca(2+)) handling, oxygen consumption, and beta-adrenergic pathway. To this aim, Sprague-Dawley rats were subjected to a wild-type Akt in vivo adenoviral gene transfer using a catheter-based technique combined with aortopulmonary crossclamping. Left ventricular (LV) contractility and intracellular Ca(2+) handling were evaluated in an isolated isovolumic buffer-perfused, aequorin-loaded whole heart preparations 10 days after the surgery. The Ca(2+)-force relationship was obtained under steady-state conditions in tetanized muscles. No significant hypertrophy was detected in adenovirus with wild-type Akt (Ad.Akt) versus controls rats (LV-to-body weight ratio 2.6+/-0.2 versus 2.7+/-0.1 mg/g, controls versus Ad.Akt, P, NS). LV contractility, measured as developed pressure, increased by 41% in Ad.Akt. This was accounted for by both more systolic Ca(2+) available to the contractile machinery (+19% versus controls) and by enhanced myofilament Ca(2+) responsiveness, documented by an increased maximal Ca(2+)-activated pressure (+19% versus controls) and a shift to the left of the Ca(2+)-force relationship. Such increased contractility was paralleled by a slight increase of myocardial oxygen consumption (14%), while titrated dose of dobutamine providing similar inotropic effect augmented oxygen consumption by 39% (P<0.01). Phospholamban, calsequestrin, and ryanodine receptor LV mRNA and protein content were not different among the study groups, while sarcoplasmic reticulum Ca(2+) ATPase protein levels were significantly increased in Ad.Akt rats. beta-Adrenergic receptor density, affinity, kinase-1 levels, and adenylyl cyclase activity were similar in the three animal groups. In conclusion, our results support an important role for Akt/PKB in the regulation of myocardial contractility and mechanoenergetics.
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Affiliation(s)
- A Cittadini
- Department of Clinical Medicine and Cardiovascular Sciences, University 'Federico II', Naples, Italy.
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Ceylan-Isik AF, LaCour KH, Ren J. Sex difference in cardiomyocyte function in normal and metallothionein transgenic mice: the effect of diabetes mellitus. J Appl Physiol (1985) 2006; 100:1638-46. [PMID: 16410376 DOI: 10.1152/japplphysiol.01273.2005] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Evidence suggests a sex difference in intrinsic physiological and diabetic myocardial contractile function related to antioxidant properties of female ovarian hormones. This study was designed to examine the effect of cardiac overexpression of antioxidant metallothionein on intrinsic and diabetic cardiomyocyte function. Weight-matched wild-type (FVB) and metallothionein transgenic mice of both sexes were made diabetic with streptozotocin (220 mg/kg). Contractile and intracellular Ca2+ properties were evaluated including peak shortening (PS), time to PS, time to 90% relengthening (TR90), maximal velocity of shortening or relengthening (±d L/d t), fura-2 fluorescence intensity change, and Ca2+ decay rate. Akt and transcription factor c-Jun levels were evaluated by Western blot. Myocytes from female FVB mice exhibited lower PS, ±d L/d t, and fura-2 fluorescence intensity change, prolonged time to PS, TR90, and Ca2+ decay compared with male FVB mice. Interestingly, this sex difference was not present in metallothionein mice. Diabetes depressed PS, ±d L/d t and caffeine-induced Ca2+ release, as well as prolonged TR90 and Ca2+ decay in male FVB mice, whereas it only reduced PS in female FVB mice. These diabetic dysfunctions were nullified by metallothionein in both sexes. Females displayed elevated Akt phosphorylation and reduced c-Jun phosphorylation. Diabetes dampened Akt phosphorylation in male FVB mice and enhanced c-Jun in both sexes. Diabetes-induced alterations in Akt phosphorylation and c-Jun were abolished by metallothionein. The sex difference in Akt phosphorylation but not c-Jun levels was reversed by metallothionein. These data indicate that antioxidant capacity plays an important role in sex differences in both intrinsic and diabetic cardiomyocyte contractile properties possibly related to phosphorylation of Akt and c-Jun.
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Affiliation(s)
- Asli F Ceylan-Isik
- Division of Pharmaceutical Sciences and Center for Cardiovascular Research and Alternative Medicine, University of Wyoming, Laramie, WY 82071, USA
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Kim J, Li Q, Fang CX, Ren J. Paradoxical effects of ginkgolide B on cardiomyocyte contractile function in normal and high-glucose environments. Acta Pharmacol Sin 2006; 27:536-42. [PMID: 16626507 DOI: 10.1111/j.1745-7254.2006.00320.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
AIM Ginkgo biloba extract is a natural product used widely for cerebral and cardiovascular diseases. It is mainly composed of terpene lactones (ginkgolide A and B) and flavone glycosides (eg quercetin and kaempferol). To better understand the cardiac electromechanical action of Ginkgo biloba extract in normal and diabetic states, this study was designed to examine the effect of ginkgolide B on cardiomyocyte contractile function under normal and high-glucose environments. METHODS Isolated adult rat ventricular myocytes were cultured for 6 h in a serum-free medium containing either normal (NG; 5.5 mmol/L) or high (HG; 25.5 mmol/L) glucose with or without ginkgolide B (0.5-2.0 microg/mL). Mechanical properties were evaluated using the IonOptix MyoCam system. Contractile properties analyzed included peak shortening (PS), maximal velocity of shortening/relengthening (+/-dl/dt), time-to-PS (TPS) and time-to-90% relengthening (TR90). Levels of essential Ca(2+) regulatory proteins sarco(endo)plasmic reticulum Ca(2+)-ATPase (SERCA2a), phospholamban (PLB) and Na(+)-Ca(2+) exchanger (NCX) were assessed by Western blotting. RESULTS Ginkgolide B nullified HG-induced prolongation in TR90. However, ginkgolide B depressed PS, +/-dl/dt and shortened TPS in NG and HG cells. Ginkgolide B also prolonged TR90 in NG cells. Western blot analysis revealed that HG upregulated SERCA2a and downregulated PLB expression without affecting that of NCX. Ginkgolide B disrupted the NG-HG response pattern in SERCA2a and NCX without affecting that of PLB. CONCLUSION Ginkgolide B affects cardiomyocyte contractile function under NG or HG environments in a paradoxical manner, which may be attributed to uneven action on Ca(2+) regulatory proteins under NG and HG conditions.
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Affiliation(s)
- J Kim
- Center for Cardiovascular Research and Alternative Medicine, Division of Pharmaceutical Sciences, University of Wyoming, Laramie, WY 82071, USA
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32
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Jiang J, Yuen V, Xiang H, McNeill JH. Improvement in cardiac function of diabetic rats by bosentan is not associated with changes in the activation of PKC isoforms. Mol Cell Biochem 2006; 282:177-85. [PMID: 16317525 DOI: 10.1007/s11010-006-1926-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2005] [Accepted: 08/09/2005] [Indexed: 11/25/2022]
Abstract
We previously demonstrated that chronic treatment with the mixed endothelin A and B (ET(A) and ET(B)) receptor blocker bosentan improved isolated working heart function in streptozotocin (STZ) diabetic rats. Endothelin-1 (ET-1) peptide levels, ET-1 mRNA and ET(A) and ET(B) receptor mRNA were all increased in diabetic hearts, but were unaffected by bosentan treatment, indicating that the beneficial effects of bosentan on heart appear to be on downstream effectors of ET-1 and ET receptors rather than the ET-1 system itself. Stimulation of ET-1 receptors leads to increased activation of protein kinase C (PKC), which is associated with PKC translocation from the cytosol to the membrane. Persistent activation of specific PKC isoforms has been proposed to contribute to diabetic cardiomyopathy. The purpose of this study was to determine whether chronic treatment with bosentan influences the activation of PKC isoforms in hearts from diabetic rats. Male Wistar rats were divided into four groups: control, bosentan-treated control, diabetic, and bosentan-treated diabetic. Diabetes was induced by the intravenous injection of 60 mg/kg streptozotocin. One week later, treatment with bosentan (100 mg/kg/day) by oral gavage was begun and continued for 10 weeks. The heart was then removed, homogenized, separated into soluble (cytosolic) and particulate (membrane) fractions and PKC isoform content in each fraction was determined by Western blotting. PKC alpha, beta2, delta, epsilon and zeta were all detected in hearts from both control and diabetic rats. However, no change in the levels or distribution between the soluble and particulate fractions of any of these isoforms could be detected in chronic diabetic hearts compared to control, whether untreated or treated with bosentan. These observations indicate that bosentan does not improve cardiac performance in STZ diabetic rats by affecting the activation of PKC isoforms.
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Affiliation(s)
- Jihong Jiang
- Division of Pharmacology and Toxicology, Faculty of Pharmaceutical Sciences, University of British Columbia, 2146 East Mall, Vancouver, British Columbia V6T 1Z3, Canada
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33
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Wold LE, Ceylan-Isik AF, Fang CX, Yang X, Li SY, Sreejayan N, Privratsky JR, Ren J. Metallothionein alleviates cardiac dysfunction in streptozotocin-induced diabetes: role of Ca2+ cycling proteins, NADPH oxidase, poly(ADP-Ribose) polymerase and myosin heavy chain isozyme. Free Radic Biol Med 2006; 40:1419-29. [PMID: 16631532 DOI: 10.1016/j.freeradbiomed.2005.12.009] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/07/2005] [Revised: 11/16/2005] [Accepted: 12/12/2005] [Indexed: 11/28/2022]
Abstract
Diabetic cardiomyopathy contributes to high morbidity and mortality in diabetic populations. It is manifested by compromised ventricular contraction and prolonged relaxation attributable to multiple causative factors including oxidative stress. This study was designed to examine the effect of cardiac overexpression of the heavy metal scavenger metallothionein (MT) on cardiac contractile function, intracellular Ca(2+) cycling proteins, stress-activated signaling molecules and the myosin heavy chain (MHC) isozyme in diabetes. Adult male wild-type (FVB) and MT transgenic mice were made diabetic by a single injection of streptozotocin (STZ). Contractile properties were evaluated in cardiomyocytes including peak shortening (PS), time-to-PS (TPS), time-to-relengthening (TR(90)), maximal velocity of shortening/relengthening (+/-dL/dt) and intracellular Ca(2+) fluorescence. Diabetes significantly depressed PS, +/-dL/dt, prolonged TPS, TR(90) and intracellular Ca(2+) clearing, elevated resting intracellular Ca(2+), reduced caffeine-induced sarcoplasmic reticulum Ca(2+) release and dampened stress tolerance at high stimulus frequencies. MT itself exhibited little effect on myocyte mechanics but it significantly alleviated STZ-induced myocyte contractile dysfunctions. Diabetes enhanced expression of the AT(1) receptor, phospholamban, the p47(phox) NADPH oxidase subunit and poly(ADP-ribose) polymerase (PARP), depressed the level of SERCA2a, Na(+)-Ca(2+) exchanger and triggered a beta-MHC isozyme switch. All of these STZ-induced alterations with the exception of depressed SERCA2a and enhanced phospholamban were reconciled by MT. Collectively, these data suggest a beneficial effect of MT in the therapeutics of diabetic cardiomyopathy, possibly through a mechanism related to NADPH oxidase, PARP and MHC isozyme switch.
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MESH Headings
- Animals
- Calcium/chemistry
- Calcium/metabolism
- Cations, Divalent/chemistry
- Diabetes Mellitus, Experimental/chemically induced
- Diabetes Mellitus, Experimental/complications
- Diabetes Mellitus, Experimental/enzymology
- Diabetes Mellitus, Experimental/metabolism
- Heart Diseases/chemically induced
- Heart Diseases/complications
- Heart Diseases/enzymology
- Heart Diseases/metabolism
- Isoenzymes/metabolism
- Male
- Metallothionein/genetics
- Metallothionein/metabolism
- Mice
- Mice, Transgenic
- Muscle Cells/metabolism
- Myosin Heavy Chains/metabolism
- NADPH Oxidases/metabolism
- Oxidative Stress
- Poly(ADP-ribose) Polymerases/metabolism
- Receptor, Angiotensin, Type 1/metabolism
- Receptor, Angiotensin, Type 2/metabolism
- Streptozocin/pharmacology
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Affiliation(s)
- Loren E Wold
- Department of Pharmacology, Physiology and Therapeutics, University of North Dakota School of Medicine, Grand Forks, 58203, USA
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Yang X, Doser TA, Fang CX, Nunn JM, Janardhanan R, Zhu M, Sreejayan N, Quinn MT, Ren J. Metallothionein prolongs survival and antagonizes senescence‐associated cardiomyocyte diastolic dysfunction: role of oxidative stress. FASEB J 2006; 20:1024-6. [PMID: 16585059 DOI: 10.1096/fj.05-5288fje] [Citation(s) in RCA: 113] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Senescence is accompanied by oxidative stress and cardiac dysfunction, although the link between the two remains unclear. This study examined the role of antioxidant metallothionein on cardiomyocyte function, superoxide generation, the oxidative stress biomarker aconitase activity, cytochrome c release, and expression of oxidative stress-related proteins, such as the GTPase RhoA and NADPH oxidase protein p47phox in young (5-6 mo) and aged (26-28 mo) FVB wild-type (WT) and cardiac-specific metallothionein transgenic mice. Metallothionein mice showed a longer life span (by approximately 4 mo) than FVB mice evaluated by the Kaplan-Meier survival curve. Compared with young cardiomyocytes, aged myocytes displayed prolonged TR(90), reduced tolerance to high stimulus frequency, and slowed intracellular Ca2+ decay, all of which were nullified by metallothionein. Aging increased superoxide generation, active RhoA abundance, cytochrome c release, and p47phox expression and suppressed aconitase activity without affecting protein nitrotyrosine formation in the hearts. These aging-induced changes in oxidative stress and related protein biomarkers were attenuated by metallothionein. Aged metallothionein mouse myocytes were more resistant to the superoxide donor pyrogallol-induced superoxide generation and apoptosis. In addition, aging-associated prolongation in TR90 was blunted by the Rho kinase inhibitor Y-27632. Collectively, our data demonstrated that metallothionein may alleviate aging-induced cardiac contractile defects and oxidative stress, which may contribute to prolonged life span in metallothionein transgenic mice.
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Affiliation(s)
- Xiaoping Yang
- Division of Pharmaceutical Sciences and Center for Cardiovascular Research and Alternative Medicine, University of Wyoming, Laramie, Wyoming 82071-3375, USA
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35
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Fang CX, Doser TA, Yang X, Sreejayan N, Ren J. Metallothionein antagonizes aging-induced cardiac contractile dysfunction: role of PTP1B, insulin receptor tyrosine phosphorylation and Akt. Aging Cell 2006; 5:177-85. [PMID: 16626396 DOI: 10.1111/j.1474-9726.2006.00201.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Aging is often accompanied by reduced insulin sensitivity and cardiac dysfunction. However, the causal relationship between the two remains poorly understood. This study was designed to determine the impact of cardiac-specific overexpression of antioxidant metallothionein (MT) on aging-associated cardiac dysfunction and impaired insulin signaling. Contractile and intracellular Ca(2+) properties were evaluated in left ventricular myocytes including peak shortening (PS), maximal velocity of shortening/relengthening (+/- dL/dt), time-to-PS (TPS), time-to-90% relengthening (TR(90)), fura-2 fluorescence intensity change (DeltaFFI) and intracellular Ca(2+) decay rate. Expression of insulin receptor, protein-tyrosine phosphatase 1B (PTP1B), phosphorylation of insulin receptor (Tyr1146) and Akt were evaluated by Western blot analysis. Aged wild-type FVB and MT transgenic mice (26-28 months old) displayed glucose intolerance and hyperinsulinemia. Cardiomyocytes from aged FVB mice exhibited prolonged TR(90) and intracellular Ca(2+) decay associated with normal PS, +/- dL/dt, TPS and DeltaFFI compared with those from young (2-3 months old) mice. Western blot analysis revealed reduced Akt expression and insulin (5 mU g(-1))-stimulated Akt phosphorylation, elevated PTP1B expression and diminished basal insulin receptor tyrosine phosphorylation associated with comparable insulin receptor expression in aged FVB mouse hearts. All of these aging-related defects in cardiac contractile function and insulin signaling (although not hyperinsulinemia and glucose intolerance) were significantly attenuated or ablated by MT transgene. These data indicate that enhanced antioxidant defense is beneficial for aging-induced cardiac contractile dysfunction and alteration in insulin signaling.
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Affiliation(s)
- Cindy X Fang
- Division of Pharmaceutical Sciences & Center for Cardiovascular Research and Alternative Medicine, University of Wyoming, Laramie, 82071, USA
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36
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Zhao XY, Hu SJ, Li J, Mou Y, Chen BP, Xia Q. Decreased cardiac sarcoplasmic reticulum Ca2+-ATPase activity contributes to cardiac dysfunction in streptozotocin-induced diabetic rats. J Physiol Biochem 2006; 62:1-8. [PMID: 16909926 DOI: 10.1007/bf03165800] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Diabetic cardiomyopathy is characterized by reduced cardiac contractility due to direct changes in myocardium function independent of vascular disease. This study is to investigate the alterations of cardiac sarcoplasmic reticulum Ca2+ -ATPase activity and cardiac function in streptozotocin-induced diabetic rats. Diabetes mellitus (DM) was induced in male Wistar rats by intraperitoneal injection of streptozotocin. The activity of myocardium sarcoplasmic reticulum Ca2+ -ATPase and the left ventricular hemodynamic parameters were measured in DM rats 4 weeks, 6 weeks and 8 weeks after streptozotocin was administered. Phospholamban mRNA expression was detected by reverse transcription-polymerase chain reaction, and the protein levels of phospholamban and sarcoplasmic reticulum Ca2+ -ATPase were determined by Western blot. Normal rats served as control group. It was found that in DM rats 4 weeks after streptozotocin injection, the cardiac function, myocardium sarcoplasmic reticulum Ca2+ -ATPase activity, phospholamban mRNA and phospholamban protein were not significantly changed compared with those in the control rats. At 6 and 8 weeks after the streptozotocin injection, DM rats showed a significant decrease in sarcoplasmic reticulum Ca2+ -ATPase activity and cardiac function, as indicated by an increase of LVEDP and a marked depression in LVSP and +/- dP/dtmax. At the same time points, increases in phospholamban mRNA and protein levels were observed in DM rats. Sarcoplasmic reticulum Ca2+ -ATPase protein level showed no significant alterations in all DM rats compared with that in control rats. Our work confirms that sarcoplasmic reticulum Ca2+ -ATPase activity is depressed in rats with streptozotocin-induced DM, which is accompanied by elevated phospholamban protein level thus contribute to the pathogenesis of cardiac dysfunction in diabetic rats.
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Affiliation(s)
- Xiao-Yan Zhao
- Institute of Cardiology, The First Affiliated Hospital, China
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Fang CX, Dong F, Ren BH, Epstein PN, Ren J. Metallothionein alleviates cardiac contractile dysfunction induced by insulin resistance: role of Akt phosphorylation, PTB1B, PPARgamma and c-Jun. Diabetologia 2005; 48:2412-21. [PMID: 16172869 DOI: 10.1007/s00125-005-1940-y] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/05/2005] [Accepted: 06/17/2005] [Indexed: 01/14/2023]
Abstract
AIMS/HYPOTHESIS Insulin resistance is concomitant with metabolic syndrome, oxidative stress and cardiac contractile dysfunction. However, the causal relationship between oxidative stress and cardiac dysfunction is unknown. This study was designed to determine the impact of overexpression of the cardiac antioxidant metallothionein on cardiac dysfunction induced by insulin resistance in mice. METHODS Whole-body insulin resistance was generated in wild-type FVB and metallothionein transgenic mice by feeding them with sucrose for 12 weeks. Contractile and intracellular Ca(2+) properties were evaluated in ventricular myocytes using an IonOptix system. The contractile indices analysed included: peak shortening (PS), time to 90% PS (TPS(90)), time to 90% relengthening (TR(90)), half-width duration, maximal velocity of shortening (+dL/dt) and relengthening (-dL/dt), fura-fluorescence intensity change (DeltaFFI) and decay rate (tau). RESULTS The sucrose-fed mice displayed glucose intolerance, enhanced oxidative stress, hyperinsulinaemia, hypertriglyceridaemia and normal body weight. Compared with myocytes in starch-fed mice, those from sucrose-fed mice exhibited depressed PS, +dL/dt, -dL/dt, prolonged TR(90) and decay rate, and reduced DeltaFFI associated with normal TPS(90) and half-width duration. Western blot analysis revealed enhanced basal, but blunted insulin (15 mU/g)-stimulated Akt phosphorylation. It also showed elevated expression of insulin receptor beta, insulin receptor tyrosine phosphorylation, peroxisome proliferator-activated receptor gamma, protein tyrosine phosphatase 1B and phosphorylation of the transcription factor c-Jun, associated with a reduced fold increase of insulin-stimulated insulin receptor tyrosine phosphorylation in sucrose-fed mice. All western blot findings may be attenuated or ablated by metallothionein. CONCLUSIONS/INTERPRETATION These data indicate that oxidative stress may play an important role in cardiac contractile dysfunction associated with glucose intolerance and possibly related to alteration in insulin signalling at the receptor and post-receptor levels.
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Affiliation(s)
- C X Fang
- Division of Pharmaceutical Sciences & Center for Cardiovascular Research and Alternative Medicine, University of Wyoming, Laramie, WY 82071-3375, USA
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Wu S, Ren J. Benfotiamine alleviates diabetes-induced cerebral oxidative damage independent of advanced glycation end-product, tissue factor and TNF-alpha. Neurosci Lett 2005; 394:158-62. [PMID: 16260089 DOI: 10.1016/j.neulet.2005.10.022] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2005] [Revised: 10/05/2005] [Accepted: 10/08/2005] [Indexed: 12/18/2022]
Abstract
Diabetes mellitus leads to thiamine deficiency and multiple organ damage including diabetic neuropathy. This study was designed to examine the effect of benfotiamine, a lipophilic derivative of thiamine, on streptozotocin (STZ)-induced cerebral oxidative stress. Adult male FVB mice were made diabetic with a single injection of STZ (200 mg/kg, i.p.). Fourteen days later, control and diabetic (fasting blood glucose >13.9 mM) mice received benfotiamine (100 mg/kg/day, i.p.) for 14 days. Oxidative stress and protein damage were evaluated by glutathione/glutathione disulfide (GSH/GSSG) assay and protein carbonyl formation, respectively. Pro-oxidative or pro-inflammatory factors including advanced glycation end-product (AGE), tissue factor and tumor necrosis factor-alpha (TNF-alpha) were evaluated by immunoblot analysis. Four weeks STZ treatment led to hyperglycemia, enhanced cerebral oxidative stress (reduced GSH/GSSG ratio), elevated TNF-alpha and AGE levels without changes in protein carbonyl or tissue factor. Benfotiamine alleviated diabetes-induced cerebral oxidative stress without affecting levels of AGE, protein carbonyl, tissue factor and TNF-alpha. Collectively, our results indicated benfotiamine may antagonize diabetes-induced cerebral oxidative stress through a mechanism unrelated to AGE, tissue factor and TNF-alpha.
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Affiliation(s)
- Shan Wu
- Division of Pharmaceutical Sciences and Center for Cardiovascular Research and Alternative Medicine, University of Wyoming, Laramie, 82071, USA
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Ceylan-Isik AF, Wu S, Li Q, Li SY, Ren J. High-dose benfotiamine rescues cardiomyocyte contractile dysfunction in streptozotocin-induced diabetes mellitus. J Appl Physiol (1985) 2005; 100:150-6. [PMID: 16166234 DOI: 10.1152/japplphysiol.00988.2005] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Diabetic cardiomyopathy is characterized by cardiac dysfunction. This study was designed to examine the effect of benfotiamine, a lipophilic derivative of thiamine, on streptozotocin (STZ)-induced cardiac contractile dysfunction in mouse cardiomyocytes. Adult male FVB mice were made diabetic with a single injection of STZ (200 mg/kg ip). Fourteen days later, control and diabetic (fasting plasma glucose > 13.9 mM) mice were put on benfotiamine therapy (100 mg.kg(-1).day(-1) ip) for another 14 days. Mechanical and intracellular Ca2+ properties were evaluated in left ventricular myocytes using an IonOptix MyoCam system. The following indexes were evaluated: peak shortening (PS), time to PS (TPS), time to 90% relengthening (TR90), maximal velocity of shortening/relengthening, resting and rise of intracellular Ca2+ in response to electrical stimulus, sarcoplasmic reticulum (SR) Ca2+ load, and intracellular Ca2+ decay rate (tau). Two- or four-week STZ treatment led to hyperglycemia, prolonged TPS and TR90, reduced SR Ca2+ load, elevated resting intracellular Ca2+ level and prolonged tau associated with normal PS, maximal velocity of shortening/relengthening, and intracellular Ca2+ rise in response to electrical stimulus. Benfotiamine treatment abolished prolongation in TPS, TR90, and tau, as well as reduction in SR Ca2+ load without affecting hyperglycemia and elevated resting intracellular Ca2+. Diabetes triggered oxidative stress, measured by GSH-to-GSSG ratio and formation of advanced glycation end product (AGE) in the hearts. Benfotiamine treatment alleviated oxidative stress without affecting AGE or protein carbonyl formation. Collectively, our results indicated that benfotiamine may rescue STZ-induced cardiomyocyte dysfunction but not AGE formation in short-term diabetes.
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Affiliation(s)
- Asli F Ceylan-Isik
- Division of Pharmaceutical Sciences and Center for Cardiovascular Research and Alternative Medicine, University of Wyoming, Laramie, Wyoming 82071, USA
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Abstract
RhoA and Rho-kinase (ROCK) participate in a wide variety of cell signal functions such as cell growth, smooth and cardiac muscle contraction, cytoskeleton rearrangement, cell migration and proliferation. In vascular smooth muscle cells, RhoA and ROCK play an important role in Ca2+ sensitization and regulate vascular smooth muscle tone. In the heart, RhoA and ROCK mediate hypertrophic response leading to cardiac hypertrophy. Recent cellular and molecular biology studies using ROCK inhibitors such as Y-27632 and fasudil have indicated a pivotal role of the RhoA-ROCK cascade in many aspects of cardiovascular function such as cardiac hypertrophy and ventricular remodeling following myocardial infarction. Inhibition of the RhoA-ROCK signaling pathway may be a suitable target for a number of cardiovascular diseases including hypertension, atherosclerosis, diabetes and hypertrophic heart failure. This review focuses on the current understanding of the RhoA-ROCK signal pathway in heart diseases and discusses the use of ROCK inhibitors as therapeutic agents for heart diseases ranging from hypertensive cardiomyopathy to heart failure.
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Affiliation(s)
- Jun Ren
- Center for Cardiovascular Research and Alternative Medicine and Division of Pharmaceutical Sciences, University of Wyoming, Laramie, WY 82071, USA.
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Ren J, Ceylan-Isik AF. Diabetic cardiomyopathy: do women differ from men? Endocrine 2004; 25:73-83. [PMID: 15711018 DOI: 10.1385/endo:25:2:073] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2004] [Revised: 10/17/2004] [Accepted: 10/21/2004] [Indexed: 11/11/2022]
Abstract
Although many aspects of cardiovascular disease are similar between women and men, it is becoming increasingly obvious that there are significant differences as well. Premenopausal women usually have a lower risk of cardiovascular diseases than age-matched men and postmenopausal women. However, the "female advantage" disappears once women are afflicted with diabetes mellitus. Heart diseases are twice as common in diabetic men and five times as common in diabetic women. It is believed that differences in sex hormones and intrinsic myocardial and endothelial functions between men and women may be responsible for this female "advantage" and "disadvantage" in normal and diabetic conditions. Most experimental and clinical studies on diabetes only included male subjects and failed to address this important gender difference in diabetic heart complications. Although female hearts may be better tolerated to stress (such as ischemia) insults than their male counterparts, female sex hormone such as estrogen may interact with certain risk factors under diabetes which may compromise the overall cardiac function. The benefit versus risk of estrogen replacement therapy on cardiac function and overall cardiovascular health in diabetes remains controversial. This review will focus on gender-related difference in diabetic heart complication--diabetic cardiomyopathy--and if gender differences in intrinsic myocardial contraction, polyol pathway metabolism, and advanced glycation endproduct formation and other neuroendocrinal regulatory mechanisms to the heart may contribute to disparity in diabetic cardiomyopathy between men and women.
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Affiliation(s)
- Jun Ren
- Division of Pharmaceutical Sciences and Center for Cardiovascular Research and Alternative Medicine, University of Wyoming, Laramie, WY 82071, USA.
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Hintz KK, Ren J. Phytoestrogenic isoflavones daidzein and genistein reduce glucose-toxicity-induced cardiac contractile dysfunction in ventricular myocytes. Endocr Res 2004; 30:215-23. [PMID: 15473131 DOI: 10.1081/erc-120037730] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Epidemiological evidence suggests a reduction in the incidence of coronary heart disease, cancer and osteoporosis in populations with a high dietary intake of plant estrogen or phytoestrogen. The clinical benefit of phytoestrogens in cereals, vegetables and medicinal plants is attracting increasing attention for the general public. In the present study, we examined the effect of phytoestrogenic isoflavones daidzein and genistein on glucose toxicity-induced cardiac mechanical malfunction simulating diabetic cardiomyopathy. Adult rat ventricular myocytes were isolated and maintained for 24 hours in normal (NG, 5.5 mM) or high glucose (HG, 25.5 mM) medium in the absence or presence of isoflavones daidzein (50 microM) or genistein (20 microM). Cardiac contractile indices were evaluated using an IonOptix MyoCam system including peak shortening (PS), maximal velocity of shortening/relengthening (+/- dL/dt), time-to-PS (TPS) and time-to-90% relengthening (TR90). Myocytes maintained in HG medium displayed altered mechanical function simulating in vivo diabetes including reduced PS, +/- dL/dt and prolonged TR90 associated with normal TPS compared to those from NG myocytes. Interestingly, these HG-induced mechanical dysfunctions were abolished by co-incubation of daidzein or genistein. However, daidzein but not genistein itself depressed PS in NG myocytes. Neither daidzein nor genistein affected any other mechanical parameters tested in NG myocytes. Collectively, these data suggest that the phytoestrogenic isoflavones daidzein and genistein may reduce glucose toxicity-induced cardiac mechanical dysfunction and thus possess therapeutic potential against diabetes-associated cardiac defects.
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Affiliation(s)
- Kadon K Hintz
- Department of Pharmacology, Physiology and Therapeutics, University of North Dakota School of Medicine, Grand Forks, North Dakota, USA
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Sosin MD, Bhatia GS, Davis RC, Lip GYH. Heart failure-the importance of ethnicity. Eur J Heart Fail 2004; 6:831-43. [PMID: 15556044 DOI: 10.1016/j.ejheart.2003.11.019] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/22/2003] [Revised: 10/31/2003] [Accepted: 11/06/2003] [Indexed: 11/20/2022] Open
Abstract
Heart failure is a major public health problem in the Western world. Aetiological factors involved in its development include hypertension, diabetes, and ischaemic heart disease--all of which differ in prevalence, and possibly mechanism, between patients of differing ethnicity. Unfortunately, epidemiological and therapeutic trials have involved almost exclusively white populations, and evidence from these trials cannot necessarily be assumed to be generalisable to populations that include high proportions of patients from other ethnic origins. This review will discuss the mechanistic and therapeutic differences that exist in heart failure between those of European origin, and patients from the major ethnic minority groups of the UK.
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Affiliation(s)
- Michael D Sosin
- University Department of Medicine, Sandwell and West Birmingham Hospitals NHS Trust, City Hospital, Birmingham B18 7QH, England, UK
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Li JB, Wang CY, Chen JW, Feng ZQ, Ma HT. Expression of liver insulin-like growth factor 1 gene and its serum level in rats with diabetes. World J Gastroenterol 2004; 10:255-9. [PMID: 14716834 PMCID: PMC4717015 DOI: 10.3748/wjg.v10.i2.255] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
AIM: To explore the effect of diabetic duration and blood glucose level on insulin like growth factor 1 (IGF-1) gene expression and serum IGF-1 level.
METHODS: Diabetes was induced into Sprague Dawley rats by alloxan and then the rats were subdivided into different groups with varying blood glucose level and diabetic duration. The parameters were measured as follows: IGF-1 mRNA by reverse transcriptase- polymerase chain reaction (RT-PCR), IGF-1 peptide and serum IGF-1 concentration by enzyme-linked immunosorbent assay (ELISA).
RESULTS: During early diabetic stage (week 2), in comparison with normal control group (NC), IGF-1 mRNA (1.17 ± 0.069 vs 0.79 ± 0.048, P < 0.001; 1.17 ± 0.069 vs 0.53 ± 0.023, P < 0.0005, respectively), IGF-1 peptide contents [(196.66 ± 14.9) ng·mg-1vs (128.2 ± 11.25) ng·mg-1, P < 0.0005; (196.66 ± 14.9) ng·mg-1vs (74.43 ± 5.33) ng·mg-1, P < 0.0001, respectively] were reduced in liver tissues of diabetic rats. The IGF-1 gene downregulation varied with glucose control level of the diabetic state, and deteriorated gradually further with duration of diabetes. By month 6, hepatic tissue IGF-1mRNA was 0.71 ± 0.024 vs 1.12 ± 0.056, P < 0.001; 0.47 ± 0.021 vs 1.12 ± 0.056, P < 0.0005, respectively. IGF-1 peptide was (114.35 ± 8.09) ng·mg-1vs (202.05 ± 15.73) ng·mg-1, P < 0.0005; (64.58 ± 3.89) ng·mg-1vs (202.05 ± 15.73) ng·mg-1, P < 0.0001 respectively. Serum IGF-1 was also lowered in diabetic group with poor control of blood glucose. On week 2, serum IGF-1 concentrations were (371.0 ± 12.5) ng·mg-1vs (511.2 ± 24.7) ng·mg-1, P < 0.0005, (223.2 ± 9.39) ng·mg-1vs (511.2 ± 24.7) ng·mg-1, P < 0.0001 respectively. By month 6, (349.6 ± 18.62) ng·mg-1vs (520.7 ± 26.32) ng·mg-1, P < 0.0005, (188.5 ± 17.35 vs 520.7 ± 26.32) ng·mg-1, P < 0.0001, respectively. Serum IGF-1 peptide change was significantly correlated with that in liver tissue (r = 0.99, P < 0.001). Furthermore, No difference was found in the above parameters between diabetic rats with euglycemia and non-diabetic control group.
CONCLUSION: The influence of diabetic status on IGF-1 gene expression in liver tissues is started from early diabetic stage, causing down regulation of IGF-1 expression, and progresses with the severity and duration of diabetic state. Accordingly serum IGF-1 level decreases. This might indicate that liver tissue IGF-1 gene expression is greatly affected in diabetes, thus contributing to reduction of serum IGF-1 level.
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Affiliation(s)
- Jian-Bo Li
- Department of Endocrinology, First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, Jiangsu Province, China.
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Abstract
Regular physical activity promotes cardiorespiratory fitness and has been considered a cornerstone for non-pharmacological treatment of more than 17 million Americans with diabetes mellitus. Physical exercise has been shown to positively affect certain cardiovascular risk factors such as insulin resistance, glucose metabolism, blood pressure and body fat composition, which are closely associated with diabetes and heart disease. With the increasingly sedentary life style in our society, routine daily exercise of moderate intensity is highly recommended to reduce cardiovascular risk, the leading cause of death in diabetic patients. Exercise produces many beneficial effects to the heart function such as reduced incidence of coronary heart disease, attenuated severity of diabetic cardiomyopathy, improved cardiac performance, cardiac reserve and autonomic regulation. Nevertheless, many diabetic patients do not appear to gain much benefit from exercise or may even be at risk of performing physical exercise. This review summarizes the benefit and risk of exercise on diabetic heart function, with a special emphasis on myocardial and autonomic function.
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Affiliation(s)
- Shiyan Li
- Division of Pharmaceutical Sciences and Graduate Neuroscience Program, University of Wyoming College of Health Sciences, P.O. Box 3375, Laramie, WY 82071-3375, USA
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