Publications by authors named "Marsh Susan A"

Pharmacists are increasingly becoming the healthcare professional who interacts most regularly with patients who have diseases or disorders for which exercise is an effective and recommended treatment. With the relative scarcity of clinical exercise physiologists in the United States, pharmacists are expected to provide lifestyle advice to their patients, especially in community (i.e.

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The educational landscape is currently experiencing a growth in the diversity of the student population. Concomitantly, the scientific community continues to work toward increasing the diversity of its workforce while ensuring equity and inclusion for all. However, there is a pressing need for educators to promote these values and aspirations and embed them into their classrooms to continue to increase the diversity of the next generation of scientists.

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Aerobic exercise training (AET) attenuates or reverses pathological cardiac remodeling after insults such as chronic hypertension and myocardial infarction. The phenotype of the pathologically hypertrophied heart depends on the insult; therefore, it is likely that distinct types of pathological hypertrophy require different exercise regimens. However, the mechanisms by which AET improves the structure and function of the pathologically hypertrophied heart are not well understood, and exercise research uses highly inconsistent exercise regimens in diverse patient populations.

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We investigated the relationship between markers of mitochondrial biogenesis, cell signaling, and antioxidant enzymes by depleting skeletal muscle glutathione with diethyl maleate (DEM) which resulted in a demonstrable increase in oxidative stress during exercise. Animals were divided into six groups: (1) sedentary control rats; (2) sedentary rats + DEM; (3) exercise control rats euthanized immediately after exercise; (4) exercise rats + DEM; (5) exercise control rats euthanized 4 h after exercise; and (6) exercise rats + DEM euthanized 4 h after exercise. Exercising animals ran on the treadmill at a 10% gradient at 20 m/min for the first 30 min.

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Heart failure treatment currently centers on symptom management, primarily through reductions in systemic blood pressure and fluid retention. The O-linked attachment of β-N-acetylglucosamine to cardiac proteins is increased in cardiovascular disease and heart failure, and O-GlcNAc transferase (OGT) is the enzyme that catalyzes this addition. Deletion of OGT is embryonically lethal, and cardiomyocyte-specific OGT knockdown causes the exacerbation of heart failure.

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A growing body of evidence demonstrates the involvement of protein modification with O-linked β-N-acetylglucosamine (O-GlcNAc) in the stress response and its beneficial effects on cell survival. Here we investigated protein O-GlcNAcylation in skeletal muscle cells exposed to oxidative stress and the crosstalk with endogenous antioxidant system. The study focused on antioxidant enzymes superoxide dismutase 2 (SOD2), catalase (CAT), and glutathione peroxidase 1 (GPX1), and transcriptional regulators proliferator-activated receptor gamma coactivator 1-α (PGC-1α) and forkhead box protein O1 (FOXO1), which play important roles in oxidative stress response and are known to be O-GlcNAc-modified.

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Post-translational modification of intracellular proteins with O-linked β-N-acetylglucosamine (O-GlcNAc) profoundly affects protein structure, function, and metabolism. Although many skeletal muscle proteins are O-GlcNAcylated, the modification has not been extensively studied in this tissue, especially in the context of exercise. This study investigated the effects of glutathione depletion and acute exercise on O-GlcNAc protein modification in rat skeletal muscle.

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Our understanding of the role of protein O-GlcNAcylation in the regulation of the cardiovascular system has increased rapidly in recent years. Studies have linked increased O-GlcNAc levels to glucose toxicity and diabetic complications; conversely, acute activation of O-GlcNAcylation has been shown to be cardioprotective. However, it is also increasingly evident that O-GlcNAc turnover plays a central role in the delicate regulation of the cardiovascular system.

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High-fat, low-carbohydrate diets (HFLCD) are often eaten by humans for a variety of reasons, but the effects of such diets on the heart are incompletely understood. We evaluated the impact of HFLCD on myocardial ischemia/reperfusion (I/R) using an in vivo model of left anterior descending coronary artery ligation. Sprague-Dawley rats (300 g) were fed HFLCD (60% calories fat, 30% protein, 10% carbohydrate) or control (CONT; 16% fat, 19% protein, 65% carbohydrate) diet for 2 wk and then underwent open chest I/R.

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Pathological cardiac hypertrophy activates a suite of genes called the fetal gene program (FGP). Pathological hypertrophy occurs in diabetic cardiomyopathy (DCM); therefore, the FGP is widely used as a biomarker of DCM in animal studies. However, it is unknown whether the FGP is a consistent marker of hypertrophy in rodent models of diabetes.

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Diets high in sugar and saturated fat (Western diet) contribute to obesity and pathophysiology of metabolic syndrome. A common physiological response to obesity is hypertension, which induces cardiac remodeling and hypertrophy. Hypertrophy is regulated at the level of chromatin by repressor element 1-silencing transcription factor (REST), and pathological hypertrophy is associated with reexpression of a fetal cardiac gene program.

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Introduction: Dystrophinopathy in the young mdx mouse model of Duchenne muscular dystrophy is comparatively mild, requires induction, and is rarely assessed with tests of systemic muscle function in whole animals.

Methods: A modified TREAT-NMD induction protocol was used to evaluate respiratory and exercise performance, starting and ending with maximum oxygen consumption (VO2max ) tests.

Results: The initial and/or final VO2max , time to exhaustion, speed at exhaustion, and total expended calories were significantly lower in mdx mice.

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Background: Exercise causes physiological cardiac hypertrophy and benefits the diabetic heart. Mammalian switch-independent 3A (mSin3A) and histone deacetylases (HDACs) 1 and 2 regulate hypertrophic genes through associations with the DNA binding proteins repressor element-1 silencing transcription factor (REST) and O-linked β-N-acetylglucosamine transferase (OGT). O-linked β-N-acetylglucosamine (O-GlcNAc) is a glucose derivative that is chronically elevated in diabetic hearts, and a previous study showed that exercise reduces cardiac O-GlcNAc.

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Cardiac hypertrophy induced by pathological stimuli is regulated by a complex formed by the repressor element 1-silencing transcription factor (REST) and its corepressor mSin3A. We previously reported that hypertrophic signaling is blunted by O-linked attachment of β-N-acetylglucosamine (O-GlcNAc) to proteins. Regular exercise induces a physiological hypertrophic phenotype in the heart that is associated with decreased O-GlcNAc levels, but a link between O-GlcNAc, the REST complex, and initiation of exercise-induced cardiac hypertrophy is not known.

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Store-operated calcium entry (SOCE) is a major Ca(2+) signaling pathway responsible for regulating numerous transcriptional events. In cardiomyocytes SOCE has been shown to play an important role in regulating hypertrophic signaling pathways, including nuclear translocation of NFAT. Acute activation of pathways leading to O-GlcNAc synthesis have been shown to impair SOCE-mediated transcription and in diabetes, where O-GlcNAc levels are chronically elevated, cardiac hypertrophic signaling is also impaired.

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The post-translation attachment of O-linked N-acetylglucosamine, or O-GlcNAc, to serine and threonine residues of nuclear and cytoplasmic proteins is increasingly recognized as a key regulator of diverse cellular processes. O-GlcNAc synthesis is essential for cell survival and it has been shown that acute activation of pathways, which increase cellular O-GlcNAc levels is cytoprotective; however, prolonged increases in O-GlcNAcylation have been implicated in a number of chronic diseases. Glucose metabolism via the hexosamine biosynthesis pathway plays a central role in regulating O-GlcNAc synthesis; consequently, sustained increases in O-GlcNAc levels have been implicated in glucose toxicity and insulin resistance.

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Aims: Increased O-linked attachment of β-N-acetylglucosamine (O-GlcNAc) to proteins has been implicated in the adverse effects of diabetes on the heart, although this has typically been based on models of severe hyperglycemia. Diabetes has also been associated with dysregulation of autophagy, a critical cell survival process; however, little is known regarding autophagy in the diabetic heart or whether this is influenced by O-GlcNAcylation or hemodynamic stress.

Main Methods: Young male rats were assigned to control (12% kcal fat/19% protein/69% carbohydrate), high fat diet (60/19/21%) and type 2 diabetic (high fat diet+low dose streptozotocin) groups for 8 weeks, followed by sham or pressure overload surgeries; animals were sacrificed 8 weeks after surgery.

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Background: The molecular mechanisms of exercise-induced cardioprotection are poorly understood. We recently reported that exercise training down-regulated gene expression of the Ras homolog gene family member A (RhoA). RhoA and its first effectors, the Rho-kinases (ROCK), have already been implicated in the pathogenesis of cardiovascular disease.

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Minimizing damage during reperfusion of the heart following an ischemic event is an important part of the recovery process, as is preventing future recurrences; however, restoring blood perfusion to the heart following ischemia can lead to apoptosis, necrosis, and finally, diminished cardiac function. Exercise reduces risk of heart disease and has been shown to improve the recovery of the heart following ischemia and reperfusion. Brief intermittent ischemic events administered prior to or following a myocardial infarction have also been demonstrated to reduce the infarct size and improve cardiac function, thereby providing cardioprotection.

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Background: The molecular mechanisms of exercise training induced cardiovascular protection are poorly understood. There is growing evidence that reactive oxygen species may be involved in a number of these adaptations and that antioxidants may be used to investigate this effect.

Objective: To determine the effects of exercise training and/or antioxidant supplementation on myocardial endothelium and vascular endothelium gene expression.

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Purpose: Exercise increases the production of reactive oxygen species (ROS) in skeletal muscle, and athletes often consume antioxidant supplements in the belief they will attenuate ROS-related muscle damage and fatigue during exercise. However, exercise-induced ROS may regulate beneficial skeletal muscle adaptations, such as increased mitochondrial biogenesis. We therefore investigated the effects of long-term antioxidant supplementation with vitamin E and α-lipoic acid on changes in markers of mitochondrial biogenesis in the skeletal muscle of exercise-trained and sedentary rats.

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