Matching Items (5)
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- All Subjects: Obesity
- Creators: Coletta, Dawn
Description
Obesity impairs skeletal muscle maintenance and regeneration, a condition that can progressively lead to muscle loss, but the mechanisms behind it are unknown. Muscle is primarily composed of multinucleated cells called myotubes which are derived by the fusion of mononucleated myocytes. A key mediator in this process is the cellular fusion protein syncytin-1. This led to the hypothesis that syncytin-1 could be decreased in the muscle of obese/insulin resistant individuals. In contrast, it was found that obese/insulin resistant subjects had higher syncytin-1 expression in the muscle compared to that of the lean subjects. Across the subjects, syncytin-1 correlated significantly with body mass index, percent body fat, blood glucose and HbA1c levels, insulin sensitivity and muscle protein fractional synthesis rate. The concentrations of specific plasma fatty acids, such as the saturated fatty acid (palmitate) and monounsaturated fatty acid (oleate) are known to be altered in obese/insulin resistant humans, and also to influence the protein synthesis in muscle. Therefore, it was evaluated that the effects of palmitate and oleate on syncytin-1 expression, as well as 4E-BP1 phosphorylation, a key mechanism regulating muscle protein synthesis in insulin stimulated C2C12 myotubes. The results showed that treatment with 20 nM insulin, 300 µM oleate, 300 µM oleate +20 nM insulin and 300 µM palmitate + 300 µM oleate elevated 4E-BP1 phosphorylation. At the same time, 20 nM insulin, 300 µM palmitate, 300 µM oleate + 20 nM insulin and 300 µM palmitate + 300 µM oleate elevated syncytin-1 expression. Insulin stimulated muscle syncytin-1 expression and 4E-BP1 phosphorylation, and this effect was comparable to that observed in the presence of oleate alone. However, the presence of palmitate + oleate diminished the stimulatory effect of insulin on muscle syncytin-1 expression and 4E-BP1 phosphorylation. These findings indicate oleate but not palmitate increased total 4E-BP1 phosphorylation regardless of insulin and the presence of palmitate in insulin mediated C2C12 cells. The presence of palmitate inhibited the upregulation of total 4EB-P1 phosphorylation. Palmitate but not oleate increased syncytin-1 expression in insulin mediated C2C12 myotubes. It is possible that chronic hyperinsulinemia in obesity and/or elevated levels of fatty acids such as palmitate in plasma could have contributed to syncytin-1 overexpression and decreased muscle protein fractional synthesis rate in obese/insulin resistant human muscle.
ContributorsRavichandran, Jayachandran (Author) / Katsanos, Christos (Thesis advisor) / Coletta, Dawn (Committee member) / Dickinson, Jared (Committee member) / Arizona State University (Publisher)
Created2017
Description
DNA methylation, a subset of epigenetics, has been found to be a significant marker associated with variations in gene expression and activity across the entire human genome. As of now, however, there is little to no information about how DNA methylation varies between different tissues inside a singular person's body. By using research data from a preliminary study of lean and obese clinical subjects, this study attempts to put together a profile of the differences in DNA methylation that can be observed between two particular body tissues from this subject group: blood and skeletal muscle. This study allows us to start describing the changes that occur at the epigenetic level that influence how differently these two tissues operate, along with seeing how these tissues change between individuals of different weight classes, especially in the context of the development of symptoms of Type 2 Diabetes.
ContributorsRappazzo, Micah Gabriel (Author) / Coletta, Dawn (Thesis director) / Katsanos, Christos (Committee member) / Dinu, Valentin (Committee member) / Barrett, The Honors College (Contributor) / Harrington Bioengineering Program (Contributor) / Department of Psychology (Contributor)
Created2013-12
Description
Problem: Overweight and obesity are global issues. There are several strategies for weight loss and maintenance as well as general lifestyle change for overall better health. The goal is to find an easy and convenient way for people to track their food intake, either for personal use and improvement, or to be used by professionals such as registered dietitians to gather data and help improve diet. Currently food journals, food frequency questionnaires and 24-hour recall are methods that are used by registered dietitians to get an idea of what is general diet is like from their patients or clients. It was proposed that pictures taken of the meal with a phone could be used as a method of recording food intake. It would be quick and extremely easy on the client; then everything from portion size, to type of food and toppings could be analyzed quickly and conveniently. If effective it could also give rise to the ability for foods to be analyzed immediately with the text or email of the picture. Methods: subjects already participating in a separate study where they were instructed to take pictures of their meals for a difference purpose were recruited. There recorded diet intake with phone pictures were able to be used from seven subjects. Subjects took a snapshot of their meals for 3 separate days and also logged on and completed a 24 hour recall with the ASA website. The pictures were analyzed and food intake, based off the pictures was entered in the program Food Processor to generate a nutritional report. The results from the ASA 24 hour recall, based on what the subject entered, were compared to the nutritional report, generated based on review of the pictures. Nutrient values that were compared include: total energy intake (calories), protein, carbohydrates, fat, vitamin C, calcium and fiber. This was done to test if the pictures could be used as a valid source. Results: It was found that there were several problems with using the pictures as a method of analyzing food intake. Out of the seven subjects the result of only one subject was close between the two methods. All other results of calculated nutrient intake varied significantly and it did not prove to be effective to use pictures to analyze food intake. Conclusions: food intake recorded by picture method may prove to be useful in the future, however there would need to be greater compliance and training on picturing food that can be accurately analyzed. Short written explanation of food type and cooking method etc. would be most beneficial to include with actual picture. Pictures of food intake may be useful in other professional areas but as of now are not useful to generate nutritional reports.
ContributorsLouden, Karina Arianne (Author) / Johnston, Carol (Thesis director) / Morse, Lisa (Committee member) / Appel, Christy (Committee member) / Barrett, The Honors College (Contributor) / School of Nutrition and Health Promotion (Contributor)
Created2013-05
Description
Obesity is now an epidemic in the United States and scientists must work to approach it from a unique angle. The focus of my thesis is the application of brown adipose tissue as a combatant for fat loss in the body. Unused as adults, brown adipose tissue increases metabolism and mitochondrial function to burn more fat in individuals that cannot lose weight conventionally. Current research works to introduce safe hormonal pathways in the sympathetic nervous system to generate more of this tissue.
ContributorsGrade, Neenah Young (Author) / Morse, Lisa (Thesis director) / Appel, Christy (Committee member) / Mayol-Kreiser, Sandra (Committee member) / Barrett, The Honors College (Contributor) / School of Life Sciences (Contributor)
Created2013-05
Description
Thirty six percent of Americans are obese and thirty three percent are overweight; obesity has become a known killer in the U.S. yet its prevalence has maintained a firm grasp on the U.S. population and continues to spread across the globe as other countries slowly adopt the American lifestyle. A survey was compiled collecting demographic and body mass index (BMI) information, as well as Tanofsky-Kraff’s (2009) “Assess Eating in the Absence of Hunger” survey questions. The survey used for this study was emailed out to Arizona State University students in Barrett, The Honors College, and the ASU School of Nutrition and Health Promotion listservs. A total of 457 participants completed the survey, 72 males and 385 females (mean age, 24.5±7.7 y; average body mass index (BMI), 23.4 ± 4.8 [a BMI of 25-29.9 is classified as overweight]). When comparing BMI with the living situation, 71% of obese students were living at home with family versus off campus with friends or alone. For comparison, 45% of normal weight students lived at home with family. These data could help structure prevention plans targeting college students by focusing on weight gain prevention at the family level. Results from the Tanofsky-Kraff (2009) survey revealed there was not a significant relationship between external or physical cues and BMI in men or women, but there was a significant positive correlation between emotional cues and BMI in women only. Anger and sadness were the emotional cues in women related to initiating consumption past satiation and consumption following several hours of fasting. Although BMI was inversely related to physical activity in this sample (r = -0.132; p=0.005), controlling for physical activity did not impact the significant associations of BMI with anger or sadness (P>0.05). This information is important in targeting prevention programs to address behavioral change and cognitive awareness of the effects of emotion on over-consumption.
ContributorsGarza, Andrea Marie (Author) / Johnston, Carol (Thesis director) / Jacobs, Mark (Committee member) / Coletta, Dawn (Committee member) / Barrett, The Honors College (Contributor) / Department of Psychology (Contributor) / School of Life Sciences (Contributor)
Created2013-05