Apple pomace influences liver‐adipose tissue inflammatory crosstalk in young female rats consuming a Western diet

Abstract

Non‐alcoholic fatty liver disease (NAFLD) is the most prevalent chronic liver disease in Western countries and it has been attributed to poor diet. NAFLD is defined by the presence of hepatic steatosis, which can progress to the more severe non‐alcoholic steatohepatitis (NASH) characterized by inflammation. Apple pomace, a waste byproduct of apple processing, is a rich source of anti‐inflammatory/antioxidant polyphenols. The objective of this study was to determine the effects of caloric replacement with apple pomace on hepatic‐adipose tissue inflammatory crosstalk and oxidative stress status. Growing (age 22–29 days) female Sprague‐Dawley rats were randomly assigned (n=8 rats/group) to consume a purified standard rodent diet (AIN‐93G), AIN‐93G/10% g/kg apple pomace (AIN/AP), Western diet, or Western/10% g/kg apple pomace (Western/AP) diets for 8 weeks. Based on histological evaluation, rats consuming Western diet had the highest hepatic fat infiltration and inflammation. Gene expression of nuclear transcription factor kappa B (NFκB), a key transcription factor of inflammation and reactive oxygen species, was upregulated in liver (p=0.009) and the adipose tissue (p=0.0003) of rats fed Western diet compared to the other diets in the experiment. Gene expression of proinflammatory interleukin‐6 (IL‐6) in both tissues as well as the tumor‐necrosis factor‐α (TNF‐α) in the adipose was upregulated in rats fed Western diet, but not Western/AP compared to rats fed standard diets. Replacing calories in Western and AIN diets with apple pomace upregulated (p<0.01) gene expression of the endogenous antioxidant glutathione (GSH). Additionally, serum total antioxidants were highest (p<0.04) and urine total antioxidants were lowest (p<0.04) in rats fed Western/AP. Collectively the results showed caloric replacement with 10% apple pomace in the Western attenuated risk factors associated with progress to NASH in a rat model suggesting the potential of apple pomace as a sustainable functional food.Support or Funding InformationThis research was funded by Hatch WVA 1017641 and the Davis College Dean's discretionary fund.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.