Adipose tissue gene expression is differentially regulated with different rates of weight loss in overweight and obese humans

Background: Moderate weight loss can ameliorate adverse health effects associated with obesity, reflected by an improved adipose tissue (AT) gene expression profile. However, the effect of rate of weight loss on the AT transcriptome is unknown. Objective: We investigated the global AT gene expression profile before and after two different rates of weight loss that resulted in similar total weight loss, and after a subsequent weight stabilization period. Design: In this randomized controlled trial, 25 male and 28 female individuals (BMI: 28-35 kg/m2) followed either a low-calorie diet (LCD; 1250 kcal/d) for 12 weeks or a very-low-calorie diet (VLCD; 500 kcal/d) for 5 weeks (weight loss (WL) period) and a subsequent weight stable (WS) period of four weeks. The WL period and WS period together is termed dietary intervention (DI) period. Abdominal subcutaneous AT biopsies were collected for microarray analysis, and gene expression changes were calculated for all three periods in the LCD group, VLCD group and between diets (ΔVLCD-ΔLCD). Results: Weight loss was similar between groups during the WL period (LCD: -8.1±0.5 kg, VLCD: -8.9±0.4 kg, difference p=0.25). Overall, more genes were significantly regulated and changes in gene expression were more extreme in the VLCD group compared to the LCD group. Gene sets related to mitochondrial function, adipogenesis and immunity/inflammation were more strongly upregulated on a VLCD compared to a LCD during the DI period (positive ΔVLCD-ΔLCD). Neuronal- and olfactory-related gene sets were decreased during the WL period and DI period in the VLCD group. Conclusions: The rate of weight loss (LCD vs. VLCD), with similar total weight loss, strongly regulates AT gene expression. Increased mitochondrial function and adipogenesis on a VLCD compared to a LCD reflect potential beneficial diet-induced changes in AT, while differential neuronal and olfactory regulation suggest functions of these genes beyond the current paradigm. In this randomized controlled trial, 53 male and female individuals (BMI: 28-35 kg/m2) underwent a dietary intervention (DI) with two different rates of weight loss consisting of either a low-calorie diet (1250 kcal/d) for 12 weeks or a very-low-calorie diet (500 kcal/d) for 5 weeks (weight loss (WL) period) and a subsequent weight stable (WS) period of four weeks. Abdominal subcutaneous AT biopsies were collected for whole-genome gene expression analysis at study start, after the WL period and after the WS period. This trial is registered with www.clinicaltrials.gov under the accession number NCT01559415.