Obesity is a major public health problem;nearly 60% of the US population is considered obese or overweight. More alarming is the increase in prevalence of """"""""super-obesity"""""""" (Class III obese) reaching in some localities 7% of the population, as in Tennessee where the PI resides. This condition is associated with severe co- morbidities, such as cardiovascular disease and type 2 diabetes, many of which are attributed to chronic inflammation, oxidative stress and insulin resistance. Roux-en-Y gastric bypass (RYGB) surgery is the most effective and sustainable weight loss procedure. Data of ours and others have shown that many of the metabolic benefits of RYGB occur in the first week postoperatively, prior to significant weight loss. These improvements are preceded by significant reductions in the circulating levels of gastric-derived ghrelin and leptin, occurring as early as 15 minutes after the surgical interruption of stomach during the RYGB procedure. These changes associate with significant reductions in oxidative stress in adipose tissue. The general hypothesis is that RYGB results in interruption of a gastric-adipose tissue axis leading to immediate (within the first week) improvements in oxidative stress and insulin sensitivity.
In specific aim 1 we will examine the cellular, tissue-specific and whole-body metabolic alterations 7 days following RYGB. Two cohorts of matched controls will be studied before and 7 days following caloric restriction (to match the post-RYGB diet) without stomach interruption: one with LAGB (laparoscopic adjusted gastric banding) and the other without any surgical procedure.
In specific aim 2 we will examine whether ghrelin replacement (restoration of unacylated to acylated ghrelin ratio) in the first week following RYGB reverses improvements in oxidative stress in adipose tissue and in insulin sensitivity. We will utilize three complimentary and comprehensive approaches: (i) In vivo studies to determine insulin sensitivity in liver and skeletal muscle and microdialysis of subcutaneous adipose tissue to assess tissue-specific oxidative stress, cytokine production and lipolysis. We will correlate metabolic improvements to intra-hepatic triglyceride content using magnetic resonance spectroscopy (MRS), and visceral adipose tissue mass using MRI and dual-energy x-ray absorptiometry (DXA). (ii) Ex vivo studies will assess mechanistic aspects of stomach-derived peptides on markers of oxidative stress and inflammation in adipose tissue explants. (iii) In vitro studies will examine changes in: (a) cellular factors of ROS production and pro- and anti-oxidative stress enzymes in adipose tissue biopsies (b) adipose tissue macrophage content via flow cytometry, RT-qPCR and immunohistochemistry (c) cellular factors involved in insulin signaling in adipose tissue and skeletal muscle. The information derived could lead to the combination of less invasive surgical procedures with pharmacologic manipulation of the levels of acylated ghrelin and/or leptin for the treatment of morbid obesity.
Obesity associates with severe co-morbidities, and the increasing prevalence constitutes a major public health problem. Our general hypothesis is that gastric bypass surgery results in interruption of a gastric- adipose tissue axis leading to immediate (within the first week) improvements in oxidative stress and insulin sensitivity. The information derived could lead to the combination of less invasive surgical procedures with pharmacologic manipulation of the levels of acylated ghrelin and/or leptin for the treatment of morbid obesity.
|Albaugh, Vance L; Banan, Babak; Ajouz, Hana et al. (2017) Bile acids and bariatric surgery. Mol Aspects Med 56:75-89|
|Tamboli, Robyn A; Antoun, Joseph; Sidani, Reem M et al. (2017) Metabolic responses to exogenous ghrelin in obesity and early after Roux-en-Y gastric bypass in humans. Diabetes Obes Metab 19:1267-1275|
|Dunn, Julia P; Abumrad, Naji N; Kessler, Robert M et al. (2017) Caloric Restriction-Induced Decreases in Dopamine Receptor Availability are Associated with Leptin Concentration. Obesity (Silver Spring) 25:1910-1915|
|Wattacheril, Julia; Rose, Kristie L; Hill, Salisha et al. (2017) Non-alcoholic fatty liver disease phosphoproteomics: A functional piece of the precision puzzle. Hepatol Res 47:1469-1483|
|Tamboli, Robyn A; Sidani, Reem M; Garcia, Anna E et al. (2016) Jejunal administration of glucose enhances acyl ghrelin suppression in obese humans. Am J Physiol Endocrinol Metab 311:E252-9|
|Albaugh, Vance L; Flynn, C Robb; Tamboli, Robyn A et al. (2016) Recent advances in metabolic and bariatric surgery. F1000Res 5:|
|Guo, Yan; Xiong, Yanhua; Sheng, Quanghu et al. (2016) A micro-RNA expression signature for human NAFLD progression. J Gastroenterol 51:1022-30|
|Kim, Seok-Hyung; Wu, Shu-Yu; Baek, Jeong-In et al. (2015) A post-developmental genetic screen for zebrafish models of inherited liver disease. PLoS One 10:e0125980|
|Albaugh, Vance L; Flynn, Charles Robb; Cai, Steven et al. (2015) Early Increases in Bile Acids Post Roux-en-Y Gastric Bypass Are Driven by Insulin-Sensitizing, Secondary Bile Acids. J Clin Endocrinol Metab 100:E1225-33|
|Sharifnia, Torfay; Antoun, Joseph; Verriere, Thomas G C et al. (2015) Hepatic TLR4 signaling in obese NAFLD. Am J Physiol Gastrointest Liver Physiol 309:G270-8|
Showing the most recent 10 out of 25 publications