BACKGROUND: Alterations in glycolysis are central to the increasing incidence of non-alcoholic fatty liver disease (NAFLD), highlighting a need for in vivo, non-invasive technologies to understand the development of hepatic metabolic aberrations.

PURPOSE: To use hyperpolarized magnetic resonance spectroscopy (MRS) and proton density fat fraction (PDFF) magnetic resonance imaging (MRI) techniques to investigate the effects of a chronic, life-long exposure to the Western diet (WD) in an animal model resulting in NAFLD; to investigate the hypothesis that exposure to the WD will result in NAFLD in association with altered pyruvate metabolism.

STUDY TYPE: Prospective.

ANIMAL MODEL: Twenty-eight male guinea pigs weaned onto a control diet (N = 14) or WD (N = 14).

FIELD STRENGTH/SEQUENCE: 3 T; T1-weighted gradient echo, T2-weighted spin-echo, three-dimensional gradient multi-echo fat-water separation (IDEAL-IQ), and broadband point-resolved spectroscopy (PRESS) chemical-shift sequences.

ASSESSMENT: Median PDFF was calculated in the liver and hind limbs. [1-

STATISTICAL TESTS: Unpaired Student's t-tests were used to determine differences in measurements between the two diet groups. The Pearson correlation coefficient was calculated to determine correlations between measurements.

RESULTS: Life-long WD consumption resulted in significantly higher liver PDFF and elevated triglyceride content in the liver. The WD group exhibited a decreased TTP for lactate production, and ex vivo analysis highlighted increased liver lactate dehydrogenase (LDH) activity.

DATA CONCLUSION: PDFF MRI results suggest differential fat deposition patterns occurring in animals fed a life-long WD characteristic of lean, or lacking excessive subcutaneous fat, NAFLD. The decreased liver lactate TTP and increased ex vivo LDH activity suggest lipid accumulation occurs in association with a shift from oxidative metabolism to anaerobic glycolytic metabolism in WD-exposed livers.

LEVEL OF EVIDENCE: 2 TECHNICAL EFFICACY STAGE: 1.