Browsing by Subject "Metabolic Syndrome"
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Item ASSESSMENT OF PHYSICAL ACTIVITY AMONG PATIENTS WITH RISK FACTORS FOR METABOLIC SYNDROME IN A RURAL COMMUNITY(2013-04-12) Peebles, RebeccaPurpose: Metabolic syndrome (MetS) is a cluster of medical conditions that synergistically increase the risk for development of cardiovascular disease and type two diabetes mellitus. The rapid and persistent rise in the prevalence of MetS has sparked much interest and debate among researchers regarding activity and inactivity physiology. Exercise as a prescription for prevention and management of this disease process has been suggested and explored. The purpose of this study was to address the relationship between physical activity levels and the presence of MetS risk factors within a rural community. Methods: Patients from a family medicine clinic in San Saba County, Texas were recruited, consented, and given a survey to complete. The survey assessed the amount of physical activity levels, presence of MetS risk factors and demographic information of each participant. Results: Frequencies of the five MetS risk factors were calculated revealing 7.7% of participants had none, 33.3% had one, and 20.5% had two. 38.5 % self-reported three or more risk factors which qualified them to have MetS. There was a medium, negative correlation, r = -0.33, n=31, between increase in moderate-to-vigorous intensity physical activity at work and a decrease in the presence of MetS risk factors. However, the relationship was not statistically significant (p=0.067). No correlation was observed between exercise and the presence of MetS risk factors (r = 0.084, n = 17, p = 0.75) or time sitting and the presence of MetS risk factors (r = 0.094, n =28, p =0.063). A one-way, between group analysis of variance showed statistical significance between high school graduates and higher levels of education, but no statistically significant differences between other levels of education or any income groups. Conclusions: Based on the data collected for this project, there is no significant association between exercise and the presence of MetS risk factors. However, over the past two decades, exercise has been well documented to decrease the development of risk factors and slow or even prevent the progression to fulminant disease. The deviation of the results of this investigation from prior research is likely due to the limitations and confounding factors of this study. Further research is needed to make definitive remarks regarding the role of exercise in prevention and management of MetS.Item Brainstem mechanisms that impair autonomic regulation of blood pressure with obesity(2018-12) Chaudhary, Parul; Schreihofer, Ann M.; Mifflin, Steve W.; Cunningham, J. Thomas; Schreihofer, Derek A.Metabolic syndrome (MetS) is emerging as a global health threat due to its strong association with increased risk for cardiovascular disease and diabetes. Currently, 20-25% of the world's population exhibits some traits of MetS, namely obesity, dyslipidemia, hyperinsulinemia, hypertension, and hyperglycemia. In addition, MetS also promotes the development of impaired short-term regulation of mean arterial pressure (AP) by baroreflexes, which normally act to stabilize AP. The resulting increased AP variability, which is an independent risk factor for poor outcomes, is overlooked as a trait of MetS and goes without evaluation or treatment. People who have controlled hypertension without minimizing elevated AP variability are still at significant risk for detrimental cardiovascular events such as stroke and cognitive decline. Therefore, understanding mechanisms impairing baroreflexes with MetS will help determine appropriate therapeutic management to restore baroreflexes and promote stability of AP. Furthermore, because sex differences in the development of impaired baroreflexes with obesity have been reported, an understanding of how females are protected would provide valuable insights for underlying causes for early onset of impaired baroreflexes in obese males and eventual development of impaired baroreflexes in obese females. In this project, I utilized a rodent model of MetS, obese Zucker rats (OZR), to examine contributions of hypertension and hyperglycemia in the development of impaired baroreflexes in male OZR, and whether hypertensive female OZR have delayed onset of impaired baroreflexes because they have the ability to maintain glycemic control. Male and female OZR have excess weight gain from an early age because the mutation of a leptin receptor renders them insensitive to leptin's actions to regulate appetite and metabolism, promoting excess intake of standard chow and storage of ingested calories. Like obese humans, OZR develop dyslipidemia, hypertension, and insulin resistance that eventually progresses to type 2 diabetes, making them a suitable model for the consequences of MetS. Young adult male OZR (12-15 weeks) develop sympathetically driven hypertension with pronounced attenuation of baroreflex control of heart rate (HR) and sympathetic nerve activity (SNA) compared to juvenile OZR and lean Zucker rats (LZR). In male OZR, the development of impaired baroreflexes coincides with blunted activation of the NTS, the brain stem region that receives baroreceptor afferent inputs to promote baroreflex-mediated changes in HR and SNA, and this deficit likely yields diminished baroreflexes observed in young adult male OZR. In the first project I examined whether improvement of impaired glycemic control in young adult male OZR restores baroreflex-mediated bradycardia and activation of the NTS. Both type 1 and type 2 diabetic rats have impaired vagally-mediated activation of the NTS, in agreement with the reported loss of glucose's ability to enhance glutamatergic neurotransmission within the NTS of hyperglycemic, diabetic rodents. Male OZR develop insulin resistance at an early age, characterized by elevated insulin and triglycerides with impaired glucose tolerance but normal fasting hyperglycemia. We examined glucose homeostasis using chronic measures of blood glucose by telemetry in undisturbed rats because of previous reports of exaggerated stress responses. We observed that although young adult (12-14 weeks old) male OZR have normal fasting blood glucose, they are chronically hyperglycemic with access to food. Treatment of OZR with metformin or pioglitazone restored fed blood glucose levels with access to food and enhanced baroreflex-mediated bradycardia and activation of the NTS, as suggested by phenylehphrine-induced c-Fos expression. In contrast, treatment of LZR did not alter glucose or affect baroreflex-mediated bradycardia and activation of the NTS. Neither treatment reduced elevated AP and insulin in OZR, suggesting the lowering of blood glucose was effective for restoring baroreflexes in young adult male OZR, even in the face of hypertension. In the second project I examined whether the delayed onset of impaired baroreflexes in hypertensive female OZR could be due to their ability to maintain a normal blood glucose and baroreflex-mediated activation of the NTS. Premenopausal obese women protected from diabetes, suggesting they would be protected from deficits produced by hyperglycemia. I observed that intact baroreflex-mediated bradycardia in young adult female OZR extended to preserved sympathetic baroreflexes and baroreflex-mediated activation of the NTS in 12-15-week-old female OZR. Furthermore, although these OZR were hypertensive and hyperinsulinemic, fed glucose levels and glucose tolerance are comparable to LZR. In contrast, by 6 months of age, baroreflex-mediated bradycardia was blunted in female OZR. However, fed glucose was only mildly elevated and baroreflex-mediated activation of the NTS was comparable in OZR and LZR. These data suggest the ability to maintain glucose homeostasis in young adult female OZR coincides with a preservation of baroreflex-mediated bradycardia and activation of the NTS. However, the later development of impaired baroreflex-mediated bradycardia in female OZR occurs through mechanisms distinct from those observed in male OZR. The third project examined whether preventing hypertension in male OZR protected against the development of impaired baroreflexes and activation of the NTS. Treatment with losartan or hydralazine normalized baseline AP in male OZR without affecting hyperinsulinemia, dyslipidemia, or hyperglycemia. Furthermore, these treatments enhanced baroreflex-mediated bradycardia and activation of the NTS in male OZR. However, even when AP was normalized in male OZR, baroreflex-mediated bradycardia was still smaller in treated OZR compared to like-treated LZR, suggesting other mechanisms also contribute to the blunted baroreflexes. Together these studies suggest that the development of hyperglycemia and hypertension in male OZR contribute to impaired baroreflex-mediated bradycardia and activation of the NTS in male OZR. However, the ability of female OZR to maintain glucose homeostasis preserves baroreflexes despite the presence of hypertension and hyperinsulinemia. Furthermore, when female OZR later develop impaired baroreflex-mediated bradycardia, this deficit occurs by mechanisms that differ from male OZR, highlighting the need to examine both sexes for the development of cardiovascular and metabolic disorders.Item Periuterine Adipose Tissue Remodeling in Rats Offered a Choice of Lard, Sucrose, and Chow(2018-05) Ahmed, Hijab; Goulopoulou, Styliani; Mallet, Robert T.; Rickards, Caroline A.; Su, Dong-MingThe impact of obesity on adipose tissue expansion differs with each adipose depot throughout the body, suggesting that obesity affects adipose tissue in a regional manner. We determined if free access to lard, sucrose solution, and chow (choice diet) would result in expansion (i.e. hypertrophy and hyperplasia) of periuterine adipose tissue and development of metabolic syndrome. Sprague-Dawley female rats were divided into 2 weight-matched groups: 1) choice group: free access to chow, sucrose solution, and lard and 2) chow group: rodent chow for 3 weeks. Choice rats had greater visceral adiposity, serum concentrations of triglycerides (30.95 ± 2.48 v. 45.20 ± 3.81 mg/dL) and fasting glucose (121.5 ± 3.9 v. 110 ± 2.4 mg/dL), and higher blood pressure (95.79 ± 1.82 v. 88.55 ± 1.25 mm Hg) compared to chow rats. Adipocyte morphology was assessed in hematoxylin and eosin-stained periuterine adipose tissue sections using NIS Elements software. Cross-sectional area/cell was greater in periuterine adipose tissue from choice compared to chow rats, indicating a hypertrophic response (779.6 ± 47.64 vs. 492.0 ± 27.76 μm2/cell, p=0.0001). Number of cells/unit area was smaller in periuterine adipose tissue from choice rats, indicating a hypoplastic response (13.9 x 10-5 ± 0.880 x 10-5 vs. 20.4 x 10-5 ±0.910 x 10-5 cells/μm2, p=0.0001). In conclusion, choice diet induced features of metabolic syndrome and periuterine adipose tissue expansion via hypertrophy in female rats.Item THE LINK BETWEEN METABOLIC RISK FACTORS AND COGNITIVE AND AFFECTIVE FUNCTIONING(2014-03) Cao, Linda M.; Edwards, Melissa L.; O' Bryant, Sid; Johnson, Leigh A.Metabolic syndrome (MetS) is a group of risk factors that collectively affects cardiovascular functioning. Some research studies have shown a negative association between metabolic risk factors and cognitive and affective functioning. Currently, there is a limited amount of literature examining the implication of MetS on affective and cognitive functioning. The current study sought to address this gap in the literature and specifically explore the relationship between MetS and affective status as well as the MetS –cognition link. Purpose (a): Metabolic syndrome (MetS) is a group of risk factors that collectively affects cardiovascular functioning. Some research studies have shown a negative association between metabolic risk factors and cognitive and affective functioning. There is a limited amount of literature examining the implication of MetS on affective and cognitive functioning. The current study sought to address this gap in the literature and specifically explore the relationship between MetS and affective status as well as the MetS –cognition link. Methods (b): Data were analyzed on 431 participants (With MetS n=366; without MetS n=165) from Project FRONTIER (Facing Rural Obstacles Now to health Through Intervention, Education, and Research). Metabolic syndrome was determined based on if participants met three of the five risk factors (yes/no). Risk factors for MetS include abdominal obesity, dyslipidemia (elevated serum triglycerides, low HDL), elevated fasting glucose, and elevated blood pressure. Cognitive functioning was measured utilizing the RBANS (Repeatable Battery for the Assessment of Neuropsychological Status), MMSE (Mini Mental Status Exam), Executive Interview 25-iteMetS (EXIT25) and affective status using the GDS (Geriatric Depression Scale) and BAI (Beck Anxiety Inventory). Independent sample T-tests were utilized to explore the relationship between MetS and affective functioning as well as examine the MetS-cognition link. Results (c): The analyses revealed significant mean group differences between those who meet criteria for MetS compared to those who do not. Conclusions (d): The result of this study suggests that the metabolic risk factors are related to cognitive and affective symptoms. It is important to investigate the relationship between factors related to cardiovascular disease and cognition as well as affective functioning in an effort to enhance a physician’s clinical diagnosis and enable better treatment of patients with chronic diseases.