Adipocyte size is associated with NAFLD independent of obesity, fat distribution, and PNPLA3 genotype

Authors

  • Elina M. Petäjä,

    Corresponding author
    1. Minerva Foundation Institute for Medical Research, Helsinki, Finland
    2. Department of Medicine, Divisions of Diabetes, Helsinki University Central Hospital, Helsinki, Finland
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  • Ksenia Sevastianova,

    1. Minerva Foundation Institute for Medical Research, Helsinki, Finland
    2. Department of Medicine, Divisions of Diabetes, Helsinki University Central Hospital, Helsinki, Finland
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  • Antti Hakkarainen,

    1. Department of Radiology, Helsinki University, and Medical Imaging Center, HUS, Helsinki, Finland
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  • Marju Orho-Melander,

    1. Department of Clinical Sciences, Diabetes and Endocrinology, University Hospital Malmo, Lund University, Malmo, Sweden
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  • Nina Lundbom,

    1. Department of Radiology, Helsinki University, and Medical Imaging Center, HUS, Helsinki, Finland
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  • Hannele Yki-Järvinen

    1. Minerva Foundation Institute for Medical Research, Helsinki, Finland
    2. Department of Medicine, Divisions of Diabetes, Helsinki University Central Hospital, Helsinki, Finland
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  • Disclosure: The authors declared no conflict of interest.

  • Funding agencies: This study was supported by grants from EVO, Sigrid Juselius Foundations and by the Academy of Finland (H.Y.-J.).

Abstract

Objective: Adipocyte hypertrophy has been suggested to be causally linked with inflammation and systemic insulin resistance. The aim of the study was to determine whether increased adipocyte size is associated with increased liver fat content due to nonalcoholic fatty liver disease (NAFLD) in humans independent of obesity, fat distribution and genetic variation in the patatin-like phospholipase domain-containing 3 gene (PNPLA3; adiponutrin) at rs738409. Design and Methods: One hundred nineteen non-diabetic subjects in a cross-sectional study with a median age of 39 [26] years, mean ± SD BMI of 30.0 ± 5.7 kg m−2 were studied. Abdominal subcutaneous (SC) adipocyte size, liver fat [proton magnetic resonance spectroscopy (1H-MRS)], intra-abdominal (IA), and abdominal SC adipose tissue volumes [magnetic resonance imaging (MRI)] and the PNPLA3 genotype at rs738409 were determined. Univariate and multiple linear regression analysis were used to identify independent predictors of liver fat content. Results: In multiple linear regression analysis, age, gender, BMI, the IA/SC ratio, and PNPLA3 genotype explained 42% of variation in liver fat content. Addition of adipocyte size (P < 0.0001) to the model increased the percent of explanation to 53%. Thus, 21% of known variation in liver fat could be explained by adipocyte size alone. Conclusions: Increased adipocyte size highly significantly contributes to liver fat accumulation independent of other causes.

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