Tumour Necrosis Factor Alpha and Atherogenic Index as Predictors of Insulin Resistance and Risks of Cardiovascular Disease among Obese Subjects in Calabar, Nigeria

Inflammation, insulin resistance and cardiovascular risks in obesity

Master's Thesis , 2016 , 152 Pages , Grade: A

Medicine - Internal Medicine

Several studies in different population indicate that inflammation may be the link between obesity, insulin resistance and cardiovascular disease. However, this relationship has not been adequately explored in our population and among Africans with increasing high rate ofobesity and IR. In this study, the association between obesity markers (Body mass index, waist circumference, and waist-hip ratio), inflammatory marker (Tumour necrosis factor-alpha), insulin resistance markers (Homeostasis model assessment of insulin resistance, insulin) and markers of cardiovascular risks (Atherogenic index of plasma, lipid profile, blood pressure) were evaluated in a total of one hundred and sixty subjects (160). One hundred and ten (110) of which were obese subjects (BMI 30kg/m2 and above) and fifty (50) non-obesecontrols. Blood pressure and fasting samples were collected. Anthropometric parameters were measured; body mass index and waist-hip ratio were calculated for all the participants recruited in this study. Obese subjects were further grouped based on their BMI values as; class I (BMI 30-34.9kg/m2), class II (BMI 35-39.9kg/m2) and class III (BMI 40kg/m2 and above). TNF-α and insulin were determined using enzyme linked immunosorbent assay (ELISA). Total cholesterol and triglyceride were determined using the enzymatic colorimetric method; LDL, VLDL, HOMA-1R, AIP were respectively calculated. High density lipoprotein was determined using the precipitation/cholesterol enzymatic method. The mean values of TNF-α, insulin, FPG, HOMA-1R, TC, TG, LDL, VLDL, AIP, SBP and DBP were all significantly higher in obese subjects compared to non-obese controls group (P<0.05). The mean value of HDL was significantly higher in the non-obese controls compared to the obese group (P<0.05). The values of WHR, TG, VLDL, DBP and AIP were significantly higher in male obese subjects compared to obese female (P<0.05). No significant differences were observed in the other parameters in the male and female obese participants. There were no significant variations in the levels of TNF-α, TC, TG, HDL, LDL, VLDL and AIP among the three groups (P>0.05). Insulin and HOMA-1R were significantly higher in class III group compared to the class I group. A significant positive correlation was observed between obesity markers (BMI, WC) and markers of insulin resistance (HOMA-1R, insulin) among the obese subjects (P<0.05).

Inhaltsverzeichnis (Table of Contents)

• ACKNOWLEDGMENT
• ABSTRACT
• TABLE OF CONTENTS
• LIST OF TABLES
• LIST OF FIGURES
• ABBREVIATIONS
• 1 INTRODUCTION
• 1.1 Background to the study
• 1.2 Statement of the problem
• 1.3 Aim and objectives of the study
• 1.3.1 Aim
• 1.3.2 Specific objectives
• 1.4 Justification of the study
• 2 LITERATURE REVIEW
• 2.1 Obesity
• 2.2 Classification of obesity
• 2.3 Prevalence of obesity
• 2.4 Causes of obesity
• 2.5 Effects of obesity on health
• 2.6 Management of obesity
• 2.7 Obesity and metabolic syndrome
• 2.8 Insulin
• 2.8.1 Synthesis, physiological effects and degradation of insulin
• 2.8.2 Insulin signal transduction pathway
• 2.9 Obesity and insulin resistance
• 2.10 Homeostasis model assessment of insulin resistance
• 2.11 Adipose tissue cellularity and changes with obesity
• 2.11.1 White Adipose Tissue
• 2.11.2 Brown Adipose Tissue
• 2.12 Mechanism of free fatty acid mediated insulin resistance
• 2.13 Obesity induced inflammation and insulin resistance
• 2.13.1 Obesity induced macrophage accumulation in the adipose tissue
• 2.14 Role of adipose tissue produced adipokines in insulin resistance
• 2.14.1 CCL2/MCP-1 and other chemokines
• 2.14.2 Interleukin-6
• 2.14.3 Leptin
• 2.15 Tumour necrosis factor-alpha
• 2.15.1 Structure of TNF-α
• 2.15.2 TNF-α cell signaling
• 2.15.3 Role of adipose tissue produced TNF-α in insulin resistance
• 2.16 Overview of lipid metabolism
• 2.16.1 Intracellular and extracellular transport pathway
• 2.16.2 Reverse cholesterol transport pathway
• 2.17 Obesity and dyslipidemia
• 2.18 Role of adipose tissue produced adipokines in dyslipidemia
• 2.19 Cardiovascular diseases
• 2.19.1 Risk factors for cardiovascular disease
• 2.19.2 Symptoms of cardiovascular diseases
• 2.19.3 Inflammation and cardiovascular diseases
• 2.20 Obesity, inflammation and cardiovascular diseases
• 2.20.1 Risk factors as biomarkers
• 2.21 Disorder of Lipid Metabolism

Zielsetzung und Themenschwerpunkte (Objectives and Key Themes)

This thesis aims to investigate the association between obesity, inflammation, insulin resistance and cardiovascular disease risk factors among obese subjects in Calabar, Nigeria. The study explores the potential role of inflammatory markers, particularly Tumour Necrosis Factor-alpha (TNF-α), in mediating the link between obesity and cardiovascular disease.

• The relationship between obesity and insulin resistance
• The role of inflammatory markers in obesity-related complications
• The association between insulin resistance and cardiovascular disease risk factors
• The impact of obesity on lipid metabolism and cardiovascular health
• The potential for early detection and management of cardiovascular disease in obese individuals

Zusammenfassung der Kapitel (Chapter Summaries)

The thesis begins with an introduction that sets the context for the study, outlining the background information on obesity, insulin resistance, and cardiovascular disease. It highlights the significance of this research in the Nigerian population, where obesity rates are increasing. The literature review provides a comprehensive overview of the current understanding of obesity, its causes, and its impact on health, particularly focusing on the role of inflammation, insulin resistance, and cardiovascular disease. The study's methodology is then described, detailing the recruitment of participants, data collection, and analysis techniques used.

The results section presents the findings of the study, analyzing the association between obesity markers, inflammatory markers, insulin resistance markers, and cardiovascular risk markers in the study population. Finally, the discussion section interprets the results, drawing conclusions about the key findings and their implications for public health. The discussion also explores the limitations of the study and suggests directions for future research.

Schlüsselwörter (Keywords)

The study focuses on the relationship between obesity, inflammation, insulin resistance, and cardiovascular disease risk factors. Key terms include: obesity, insulin resistance, cardiovascular disease, inflammatory markers, Tumour Necrosis Factor-alpha (TNF-α), Atherogenic Index, lipid profile, body mass index, waist circumference, waist-hip ratio, Homeostasis Model Assessment of Insulin Resistance (HOMA-IR), and biomarkers.

• College: University of Calabar
• Course: Chemical Pathology/Immunology
• Grade: A
• Author: Chidozie Agu (Author)
• Publication Year: 2016
• Pages: 152
• Catalog Number: V342187
• ISBN (eBook): 9783668390355
• ISBN (Book): 9783668390362
• Language: English
• Tags: tumour, necrosis, factor, alpha, atherogenic, index, predictors, insulin, resistance, risks, cardiovascular, disease, among, obese, subjects, calabar, nigeria, inflammation