A Systematic Review of the Effect of Lifestyle Interventions on Adipose Tissue Gene Expression: Implications for Carcinogenesis

Abstract

Objective: The mechanisms driving the associations between body weight and physical activity levels and multiple types of cancer are not yet well understood. The purpose of this review was to examine the effects of lifestyle interventions on proposed biomarkers of lifestyle and cancer risk at the level of adipose tissue in humans. Methods: Embase, MEDLINE, and CINAHL were searched by using keywords relating to exercise or diet interventions, adipose tissue biology, and outcomes of interest. Eligible studies included randomized clinical trials of exercise and/or dietary interventions in humans compared with control or other interventions, reporting the collection of subcutaneous abdominal adipose tissue. Results: Nineteen studies met criteria for inclusion. Eight studies modified dietary intake, five altered exercise levels, and six studies used a combination of both. Change in subcutaneous adipose tissue gene expression was most commonly observed with dietary weight loss, with a pattern of decrease in leptin, tumor necrosis factor alpha, and interleukin 6, along with an increase in adiponectin. There was limited change with exercise-only interventions or study arms. Conclusions: Interventions leading to weight loss result in an altered gene expression of adipokines and inflammatory markers in subcutaneous adipose tissue, while less change in gene expression was noted with exercise alone.

Effects of long-term exercise on plasma adipokine levels and inflammation-related gene expression in subcutaneous adipose tissue in sedentary dysglycaemic, overweight men and sedentary normoglycaemic men of healthy weight

“…Previous studies on exercise and adipokines have described minor effects, at least compared with different weight-loss regimes [20]. These observations are in agreement with our study, which revealed modest changes in mRNA levels (Fig.…”

“…Whereas several scientists have described adipose tissue responses to different weight-loss regimens in a variety of human populations and animal models [15,24,35,52] is a lack of studies on the response to exercise, and especially in reporting results after a long-term period of exercise in humans [15,20,21]. One study applied microarrays on scWAT before and after 6 months of an exercise intervention in 14 postmenopausal women and found no apparent alterations in transcript levels [24].…”

“…Numerous studies have focused on the effect of different types of exercise on circulating levels of adipose tissuederived factors [3,[17][18][19]. However, the main body of literature on adipokines and exercise is limited to plasma analyses of one or a few targets and the effects of acute exercise [3,[19][20][21][22] confounded by weight loss [23] or focused on only visceral adipose tissue [3,17,18]. Few studies have addressed long-term exercise-induced alterations in scWAT expression of such factors [22,24], and these studies have only been performed in insulin-sensitive women [22,24].…”

Randomized trial of weight loss in primary breast cancer: Impact on body composition, circulating biomarkers and tumor characteristics

“…c and d ). These findings stand in stark contrast to the conclusions of a systematic review by Campbell et al . of 19 studies that evaluated gene expression in relation to weight loss and PA interventions in an effort to derive implications for carcinogenesis.…”

Overweight and obesity during adolescence increases the risk of renal cell carcinoma

“…23 Adiponectine is reduced by adipose tissue hypoxia and oxidative stress, 10 especially so in central fat distribution and increases in serum by weight loss. 24 Obese children also have lower serum adiponectin levels. 25 Hypertension is another established risk factor for RCC.…”