Abstract 12815: Changes in Circulating microRNA-375 Levels in Response to Lifestyle Interventions and Improvements in Visceral Adiposity and Hepatic Fat Content: The CENTRAL Trial

Abstract

Introduction: MicroRNA (miRNAs) are short non-coding RNAs that regulate gene expression at the translational level. Circulating exosomal miRNAs have emerged as novel biomarkers of obesity, insulin resistance, and related metabolic abnormalities. miR-375 has been identified as a regulator of insulin secretion, and miR-375 may also be involved in regulating visceral adiposity and ectopic fat accumulation in the liver. Hypothesis: We aimed to investigate whether changes in circulating miR-375 induced by lifestyle interventions were related to improved visceral adiposity and hepatic fat depot among individuals with abdominal obesity. Methods: This study included adults with abdominal obesity from an 18-month diet and physical activity intervention study (the CENTRAL trial) and with available data on circulating miR-375-3p at baseline (n=222) and 18 months (n=152). Magnetic resonance imaging (MRI) was performed to assess body fat distribution and ectopic fat depots. Outcome measurements included 18-month changes in abdominal (total [TAT], visceral [VAT], deep subcutaneous [DSAT], superficial subcutaneous [SSAT]) adipose tissue area and intrahepatic fat content. Results: At baseline, higher levels of miR-375 were related to lower degrees of BMI ( p =0.0006), waist circumference ( p =0.0008), as well as abdominal adipose tissue area (TAT [ p =0.0024], VAT [ p =0.059], DSAT [ p =0.011], and SSAT [ p =0.0027]). There was a significant increase in circulating miR-375 levels after the 18-month lifestyle interventions ( P by paired t-test < 0.0001). When we analyzed effects (β) of per 1 SD increase in miR-375 changes on the outcomes after adjusting for covariates including baseline levels of miR-375 and BMI, we found that greater increase in miR-375 was associated with larger reductions of VAT (β -8.09 [3.09] cm 2 , p =0.01), as well as DSAT (β -7.87 [2.21] cm 2 , p =0.001) and intrahepatic fat content (β -1.38% [0.5%], p =0.006) at 18 months. Conclusions: Circulating miR-375 levels significantly increased after the long-term lifestyle interventions, and greater increases in miR-375 were related to significant improvements in visceral adiposity and liver fat content that are closely related to insulin resistance in adults with abdominal obesity.