The immune remodel: Weight loss-mediated inflammatory changes to obesity

Abstract

Obesity is an escalating world problem that contributes to the complexity and cost of treatment of metabolic disorders. Obesity is the result of increased storage of energy in the form of adipose tissue, reducing the quality of daily life, and interfering with longevity. Obesity is also a chronic, low-grade inflammatory disorder. The inflammatory processes affect many organ systems with expanded numbers of immune cells and increased cytokine production. Long-term weight loss is difficult to achieve and maintain. Lifestyle modifications, pharmacologic treatments, and surgical methods are increasingly utilized to ameliorate excess body weight and the comorbidities of obesity, such as diabetes, cardiovascular disease, dyslipidemia, and cancers. Weight loss is also touted to reduce inflammation. Here we review the current literature on human obesity-related systemic and local changes to the immune system and circulating inflammatory mediators. Further, we consider the impact of weight loss to reduce the burden of inflammation, bearing in mind the different methods of weight loss—behavioral change vs. surgical intervention. Impact statement As the prevalence and severity of obesity expand, the negative impact of excess adiposity affects every system of the body. Given that obesity is a subversive attack on the immune system, weight loss should improve inflammation locally and systemically. Weight management strategies like dieting, exercise, and bariatric surgery, thus have the opportunity to reduce the burden of inflammation.

Serum Adipocytokines Levels and Their Association with Insulin Sensitivity in Morbidly Obese Individuals Undergoing Bariatric Surgery

“…31 One of the important and most abundant immune cells infiltrating the adipose tissue in obesity are macrophages, 10 and MCP-1 is an important chemoattractant chemokine produced by adipose tissue mediating macrophage recruitment. 2 We found increased circulating levels of MCP-1 in obese individuals as compared to non-obese ones, but the difference was not statistically significant. Dahlman et al 32 found that expression of MCP-1 is significantly higher in obese as compared to lean individuals, but circulating levels showed no changes among their study groups suggesting that obesity produced only local changes of MCP-1 in adipose tissue.…”

“…CRP is the most often measured inflammatory marker and has consistently correlated with weight, BMI and waist to hip ratios as well as insulin resistance. 2,20 CRP has become the marker of metainflammation. Based on the available literature and the findings of our study, obesity is associated with a general inflammatory response that cannot be simply attributed to mere imbalance between proand anti-inflammatory status.…”

“… 1 Despite significant advances in our understanding of the underlying mechanisms of weight gain and associated comorbidities like insulin resistance and cardiovascular risk, the prevalence of obesity and metabolic syndrome is escalating at an unprecedented rate. 2 Worldwide, obesity has nearly tripled since 1975. Presently, the majority of the world’s population lives in countries in which obesity is responsible for more fatalities than malnutrition and underweight status.…”

“…A review of the scientific literature suggests that in response to changes in the nutritional cues in the setting of varied genetic and environmental factors, the adipose tissue undergoes dynamic remodelling. 2 This is evident in terms of quantitative and qualitative alterations in the population of adipocytes, thereby placing these cells under an immense metabolic and oxidative stress. 2 This remodeling in adipose tissue is closely related to the changes in tissue functions like alterations in adipokine secretion, local hypoxia and adipocyte death, inflammation and worsening of metabolic health.…”

“… 2 This is evident in terms of quantitative and qualitative alterations in the population of adipocytes, thereby placing these cells under an immense metabolic and oxidative stress. 2 This remodeling in adipose tissue is closely related to the changes in tissue functions like alterations in adipokine secretion, local hypoxia and adipocyte death, inflammation and worsening of metabolic health. 7 Active secretion of a variety of adipocytokines, which modulate metabolic homeostasis, has been observed in obesity.…”