Israel Medical Association Journal

Obesity is a growing global health concern, with its prevalence contributing to the rise of multiple chronic conditions, including autoimmune diseases. In this review I explore the intricate relationship between obesity and autoimmunity, focusing on how excess adiposity can affect immune responses and promote the development of autoimmune disorders. Obesity alters adipose tissue architecture, promoting chronic low-grade inflammation and triggering the release of pro-inflammatory cytokines, which contribute to immune system dysregulation. Adipose tissue is no longer seen as merely an energy store but as an active endocrine organ that interacts with the immune system. The review delves into mechanisms such as the role of adipokines, altered T cell function, and the recruitment of immune cells to inflamed adipose tissue, which together exacerbate autoimmune risk in obese individuals. Genetic and environmental factors also play a critical role in these processes, as polymorphisms and high-fat diets have been shown to influence both obesity and autoimmune susceptibility. Last, the review explores potential therapeutic strategies, such as lifestyle interventions and targeting obesity-driven inflammatory pathways, which could mitigate autoimmunity. Understanding the connection between obesity and autoimmunity offers insights into more effective interventions for patients suffering from these intertwined conditions.

Background: Obesity has become a major public health problem worldwide.

Objectives: To examine the effect of orlistat in promoting weight loss and its specific effect on the visceral adipose tissue and subcutaneous adipose tissue as evaluated by computed tomography.

Methods: A prospective case series study of 10 obese subjects was conducted. The 6 women and 4 men, age 50–67 years (mean 59 ± 8 years), had a mean body mass index of 34.1 ± 3.2 kg/m². All subjects were prescribed a mildly hypocaloric diet (600 kcal/day deficit). In addition, all subjects were treated with orlistat 120 mg 3 times a day for 20.1 ± 7 weeks.

Results: The subjects had lost approximately 8.2 kg each, or 8.4% of their initial body weight. Mean body weight decreased from 98 ± 13 to 89.8 ± 13.6 kg at the last follow-up visit (P = 0.0001) mean BMI[1] decreased from 34.1 ± 3.2 to 30.3 ± 3.9 kg/m² (P = 0.0001), and mean waist circumference from 113.8 ± 11.4 to 107.6 ± 10 cm (P = 0.0006). Mean total abdominal adipose tissue volume, evaluated by computed tomography, decreased from 426 ± 104.3 to 369.8 ± 99.6 mm³ (P = 0.0001). Mean abdominal SAT[2] volume decreased from 251.1 ± 78.8 to 224 ± 81.1 mm³ (P = 0.006), and mean abdominal VAT[3] volume decreased from 176 ± 76.7 to 141.6 ± 67 mm³ (P = 0.0001). Thus, the total abdominal adipose tissue volume for the whole group decreased by 15.4%, and most of this decrease was attributable to the reduction in VAT (24.8%) as opposed to SAT (only 12% reduction) (P = 0.03). The weight reduction that occurred during the study was accompanied by a statistically significant reduction in levels of total cholesterol, low density lipoprotein-cholesterol, triglycerides, and fasting blood glucose.

Conclusions: Our results demonstrate the effect of orlistat in reducing human visceral adipose tissue as evaluated by CT. The benefit of the treatment is further supported by the statistically significant reduction in cardiovascular risk factors.

 
[1] BMI = body mass index

[2] SAT = subcutaneous adipose tissue

[3] VAT = visceral adipose tissue