Exercise training reduces inflammatory metabolic activity of visceral fat assessed by¹⁸F‐FDG PET/CT in obese women

Abstract

ObjectivesObesity plays pivotal roles in the increased risk of cardiometabolic disease via induction of the inflammatory reaction from macrophages in visceral adipose tissue (VAT), which may elevate the inflammatory activity of VAT. This prospective study aimed to evaluate whether the inflammatory activity of VAT existed in association with systemic inflammation, and whether exercise could ameliorate the inflammatory activity of VAT assessed by 18F‐fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) in obese women.Design and PatientsA total of 23 obese women who participated in an exercise program were included. Subjects underwent 18F‐FDG PET/CT before the start of the exercise program (baseline) and after the completion of the 3‐month exercise program. For the assessment of VAT metabolic activity, the maximum standardized uptake value (SUVmax) and the mean standardized uptake value (SUVmean) were measured. The SUVmax of spleen, bone marrow (BM) and the high‐sensitivity C‐reactive protein (hsCRP) were used as a surrogate marker for systemic inflammation.ResultsBaseline SUVmax of VAT was positively correlated with the SUVmax of spleen, BM and hsCRP, whereas VAT SUVmean was not correlated. Exercise reduced SUVmax of VAT in addition to adiposity, the SUVmax of spleen, BM and hsCRP. However, VAT SUVmean was not significantly changed. Furthermore, the association of SUVmax of VAT, and the SUVmax of spleen, BM and hsCRP was no longer relevant after exercise.ConclusionIn obese women, the SUVmax of VAT assessed by 18F‐FDG PET/CT was associated with systemic inflammation and exercise reduced the SUVmax of VAT and abrogated its association with systemic inflammation.

Serum IL‐36 cytokines levels in type 2 diabetes mellitus patients and their association with obesity, insulin resistance, and inflammation

“…The BMI index of T2DM patients in this study group was higher than that of normal subjects, which indicates that T2DM patients had a tendency to be obese. Increased fat tissue is accompanied by inflammatory reactions in obese patients, including the infiltration of macrophages and other immune cells and increased secretion of adipokines, IL‐6, MCP‐1, TNF‐α, and leptin 12 . Inflammatory cytokines interact with the endocrine and immune systems, causing structural changes and dysfunction of pancreatic islet β cells and IR, which ultimately leads to the occurrence of T2DM 13 .…”

Effect of Exercise on Inflamed Psoas Muscle in Women with Obesity: A Pilot Prospective 18F-FDG PET/CT Study

“…Diagnostics 2021, 11, 164 2 of 10 emission tomography/computed tomography (PET/CT), a non-invasive glucose imaging technique, is well-known to evaluate the inflammatory activity of inflamed tissue, such as vulnerable atherosclerotic plaques [11,12]. As macrophages are also increased in inflamed skeletal muscle [6][7][8], it would also be feasible to use the 18 F-FDG PET/CT to evaluate the inflammatory activity of inflamed skeletal muscle.…”

“…For the assessment of skeletal muscle metabolism, psoas muscle (PM) mass has been widely used as a representative index of skeletal muscle mass due to its relative independence from physical activity levels, compared to appendicular muscle mass [13]. Furthermore, recently, Kim et al reported that 18 F-FDG uptake of PM was increased in populations with metabolic syndrome, which is strongly associated with obesity [14]. Thus, we postulated that the metabolic activity of PM, assessed by 18 F-FDG PET/CT, could reflect the inflammatory activity in obesity-induced skeletal muscle inflammation.…”

“…Chronic exercise is known to have a protective effect on cardiometabolic disease, partly through its anti-inflammatory effect on chronic systemic inflammation which can be synergistically induced by inflammatory activity in both visceral fat and skeletal muscle [ 8 , 15 ]. Several previous studies have reported that physical exercise could decrease visceral fat mass with an inhibition of inflammatory activity in visceral fat via the use of various imaging modalities such as CT, magnetic resonance imaging (MRI), or 18 F-FDG PET/CT in populations with obesity [ 16 , 17 , 18 ]. In addition to visceral fat, physical exercise also has been known to show anti-inflammatory effects on skeletal muscle in both human and animal studies [ 19 , 20 ].…”

“…Glucose metabolism is upregulated in inflammatory cells, such as macrophages, which is a hallmark of the inflammatory process. 18…”