title: White adipose tissue apolipoprotein C-I secretion in relation to delayed plasma clearance of dietary fat in humans.
abstract: OBJECTIVE
  White adipose tissue (WAT) dysfunction is characterized by delayed clearance of dietary triglyceride-rich lipoproteins (TRL). We reported that apolipoprotein (apo) C-I, a transferable apolipoprotein that inhibits lipoprotein lipase activity when bound to TRL, was produced by a human adipocyte model. Thus, we aimed to determine whether increased WAT apoC-I secretion is related to delayed dietary fat clearance in humans.
  
  
  RESULTS
  After the ingestion of a (13)C-triolein-labeled high-fat meal, postmenopausal obese women with high-fasting WAT apoC-I secretion (median >0.81 μmol/L per g/4 hours, n=9) had delayed postprandial plasma clearance of (13)C-triglyceride and (13)C-nonesterified fatty acids over 6 hours compared with controls. WAT apoC-I secretion over 4 hours correlated with fasting total and non-high-density lipoprotein apoC-I but not with high-density lipoprotein apoC-I and was the primary predictor of 4-hour postprandial increases in TRL apoC-I. Correction for TRL apoC-I eliminated the association of WAT apoC-I with 6-hour area under the curve of plasma (13)C-triglyceride; correction for insulin sensitivity or inflammation did not. Finally, in addition to apoC-I, WAT secreted considerable amount of apoC-II, apoC-III, and apoE over 24 hours; however, only WAT apoC-I secretion was associated with 6-hour area under the curve of plasma (13)C-triglyceride.
  
  
  CONCLUSIONS
  Increased WAT apoC-I secretion in obese women is associated with delayed postprandial dietary fat clearance mediated by increased TRL apoC-I. Thus, we hypothesize that reducing WAT apoC-I secretion ameliorates WAT dysfunction and associated cardiometabolic risks in humans.
authors.affiliation: Institut de recheches cliniques de Montréal (IRCM), Montréal, Québec, Canada.
authors.forename: Hanny
authors.initials: H
authors.lastname: Wassef
authors.forename: Huda
authors.initials: H
authors.lastname: Salem
authors.forename: Simon
authors.initials: S
authors.lastname: Bissonnette
authors.forename: Alexis
authors.initials: A
authors.lastname: Baass
authors.forename: Robert
authors.initials: R
authors.lastname: Dufour
authors.forename: Jean
authors.initials: J
authors.lastname: Davignon
authors.forename: May
authors.initials: M
authors.lastname: Faraj
mesh_terms: D052436:Adipose Tissue, White / Q000378:metabolism*; D000368:Aged; D053302:Apolipoprotein C-I / Q000097:blood / Q000378:metabolism*; D019540:Area Under Curve; D001706:Biopsy; D004041:Dietary Fats / Q000008:administration & dosage / Q000097:blood*; D005230:Fatty Acids, Nonesterified / Q000097:blood; D005260:Female; D006801:Humans; D008075:Lipoproteins, HDL / Q000097:blood; D008875:Middle Aged; D009765:Obesity / Q000097:blood* / Q000503:physiopathology; D019518:Postprandial Period; D011792:Quebec; D013997:Time Factors; D014280:Triglycerides / Q000097:blood; D014304:Triolein / Q000378:metabolism
chemical_list: C505803:APOC1 protein, human; D053302:Apolipoprotein C-I; D004041:Dietary Fats; D005230:Fatty Acids, Nonesterified; D008075:Lipoproteins, HDL; D014280:Triglycerides; D014304:Triolein