title: PLTP activity decreases with weight loss: changes in PLTP are associated with changes in subcutaneous fat and FFA but not IAF or insulin sensitivity.
abstract: Phospholipid transfer protein (PLTP) activity is elevated in obese and diabetic subjects. No prospective studies have examined the effect of weight loss on PLTP activity and assessed whether the resultant changes in activity are related to changes in body weight, insulin resistance, or both. PLTP activity was measured at baseline in 46 subjects (body mass index = 19-64 kg/m2) and after diet-induced weight loss in 19 of the obese subjects. Total body fat mass (FM) by dual-energy X-ray absorptiometry, intraabdominal fat (IAF), and abdominal subcutaneous fat (SQF) by CT scan, insulin sensitivity (SI) by frequently sampled intravenous glucose tolerance test, leptin, and lipids were determined. At baseline, PLTP activity correlated with FM (r = 0.36, P = 0.02) and SQF (r = 0.31, P = 0.045), but not with IAF (r = 0.16, P = 0.32) or SI (r = 0.10, P = 0.52). With diet-induced weight loss (16 +/- 7.3 kg), PLTP activity significantly decreased 9.1% (P = 0.002). The change in PLTP activity correlated with the change in SQF (r = 0.55, P = 0.014) (33.6% decrease), but not with IAF (r = 0.09, P = 0.73) or SI (r = 0.18, P = 0.44), and was highly correlated with the change in nonesterified fatty acid (NEFA) (r = 0.71, P < 0.001). In conclusion, elevated PLTP activity in obese subjects is likely a result of increased body fat, reflected by SQF, and is influenced by NEFAs but is not directly related to insulin resistance.
authors.affiliation: Division of Metabolism, Endocrinology and Nutrition, Department of Medicine, University of Washington, Seattle, WA 98195, USA. smurdoch@u.washington.edu
authors.forename: Susan J
authors.initials: SJ
authors.lastname: Murdoch
authors.forename: Steven E
authors.initials: SE
authors.lastname: Kahn
authors.forename: John J
authors.initials: JJ
authors.lastname: Albers
authors.forename: John D
authors.initials: JD
authors.lastname: Brunzell
authors.forename: Jonathan Q
authors.initials: JQ
authors.lastname: Purnell
mesh_terms: D000005:Abdomen / Q000502:physiology*; D000273:Adipose Tissue / Q000378:metabolism*; D015415:Biomarkers; D002352:Carrier Proteins / Q000097:blood / Q000378:metabolism*; D003430:Cross-Sectional Studies; D005230:Fatty Acids, Nonesterified / Q000378:metabolism*; D005260:Female; D006801:Humans; D007333:Insulin Resistance / Q000502:physiology*; D008297:Male; D008565:Membrane Proteins / Q000097:blood / Q000378:metabolism*; D009765:Obesity / Q000378:metabolism; D049294:Phospholipid Transfer Proteins; D040521:Subcutaneous Tissue / Q000378:metabolism*; D015431:Weight Loss / Q000502:physiology*
chemical_list: D015415:Biomarkers; D002352:Carrier Proteins; D005230:Fatty Acids, Nonesterified; D008565:Membrane Proteins; D049294:Phospholipid Transfer Proteins