Serum Afamin a Novel Marker of Increased Hepatic Lipid Content

Front Endocrinol (Lausanne). 2021 Sep 16:12:670425. doi: 10.3389/fendo.2021.670425. eCollection 2021.

Abstract

Aim: Afamin is a liver-produced glycoprotein, a potential early marker of metabolic syndrome. Here we investigated regulation of afamin in a course of the metabolic disease development and in response to 3-month exercise intervention.

Methods: We measured whole-body insulin sensitivity (euglycemic hyperinsulinemic clamp), glucose tolerance, abdominal adiposity, hepatic lipid content (magnetic resonance imaging/spectroscopy), habitual physical activity (accelerometers) and serum afamin (enzyme-linked immunosorbent assay) in 71 middle-aged men with obesity, prediabetes and newly diagnosed type 2 diabetes. Effects of 3-month exercise were investigated in 22 overweight-to-obese middle-aged individuals (16M/6F).

Results: Prediabetes and type 2 diabetes, but not obesity, were associated with increased serum afamin (p<0.001). Afamin correlated positively with hepatic lipids, fatty liver index and liver damage markers; with parameters of adiposity (waist circumference, %body fat, adipocyte diameter) and insulin resistance (fasting insulin, C-peptide, HOMA-IR; p<0.001 all). Moreover, afamin negatively correlated with whole-body insulin sensitivity (M-value/Insulin, p<0.001). Hepatic lipids and fasting insulinemia were the most important predictors of serum afamin, explaining >63% of its variability. Exercise-related changes in afamin were paralleled by reciprocal changes in insulinemia, insulin resistance and visceral adiposity. No significant change in hepatic lipid content was observed.

Conclusions: Subjects with prediabetes and type 2 diabetes had the highest serum afamin levels. Afamin was more tightly related to hepatic lipid accumulation, liver damage and insulin resistance than to obesity.

Keywords: afamin; exercise; hepatic lipids; insulin resistance; prediabetes; type 2 diabetes.

Publication types

  • Clinical Trial
  • Observational Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adiposity*
  • Adult
  • Biomarkers / blood*
  • Body Mass Index
  • Carrier Proteins / blood*
  • Cross-Sectional Studies
  • Diabetes Mellitus, Type 2 / blood
  • Diabetes Mellitus, Type 2 / diagnosis*
  • Fatty Liver / blood
  • Fatty Liver / diagnosis*
  • Female
  • Follow-Up Studies
  • Glycoproteins / blood*
  • Humans
  • Insulin Resistance
  • Lipid Metabolism
  • Male
  • Obesity / physiopathology*
  • Prediabetic State / blood
  • Prediabetic State / diagnosis*
  • Prognosis
  • Serum Albumin, Human

Substances

  • AFM protein, human
  • Biomarkers
  • Carrier Proteins
  • Glycoproteins
  • Serum Albumin, Human