Elevated plasma free fatty acids increase cardiovascular risk by inducing plasma biomarkers of endothelial activation, myeloperoxidase and PAI-1 in healthy subjects.
BACKGROUND
CVD in obesity and T2DM are associated with endothelial activation, elevated plasma vascular inflammation markers and a prothrombotic state. We examined the contribution of FFA to these abnormalities following a 48-hour physiological increase in plasma FFA to levels of obesity and diabetes in a group of healthy subjects.


METHODS
40 non-diabetic subjects (age = 38 +/- 3 yr, BMI = 28 +/- 1 kg/m2, FPG = 95 +/- 1 mg/dl, HbA1c = 5.3 +/- 0.1%) were admitted twice and received a 48-hour infusion of normal saline or low-dose lipid. Plasma was drawn for intracellular (ICAM-1) and vascular (VCAM-1) adhesion molecules-1, E-selectin (sE-S), myeloperoxidase (MPO) and total plasminogen inhibitor-1 (tPAI-1). Insulin sensitivity was measured by a hyperglycemic clamp (M/I).


RESULTS
Lipid infusion increased plasma FFA to levels observed in obesity and T2DM and reduced insulin sensitivity by 27% (p = 0.01). Elevated plasma FFA increased plasma markers of endothelial activation ICAM-1 (138 +/- 10 vs. 186 +/- 25 ng/ml), VCAM-1 (1066 +/- 67 vs. 1204 +/- 65 ng/ml) and sE-S (20 +/- 1 vs. 24 +/- 1 ng/ml) between 13-35% and by > or = 2-fold plasma levels of myeloperoxidase (7.5 +/- 0.9 to 15 +/- 25 ng/ml), an inflammatory marker of future CVD, and tPAI-1 (9.7 +/- 0.6 to 22.5 +/- 1.5 ng/ml), an indicator of a prothrombotic state (all p < or = 0.01). The FFA-induced increase was independent from the degree of adiposity, being of similar magnitude in lean, overweight and obese subjects.


CONCLUSIONS
An increase in plasma FFA within the physiological range observed in obesity and T2DM induces markers of endothelial activation, vascular inflammation and thrombosis in healthy subjects. This suggests that even transient (48-hour) and modest increases in plasma FFA may initiate early vascular abnormalities that promote atherosclerosis and CVD.
Diabetes Division, Department of Medicine, The University of Texas Health Science Center at San Antonio, Texas-78229, USA.
Manoj
M
Mathew
Eric
E
Tay
Kenneth
K
Cusi
D000328:Adult; D001786:Blood Glucose / Q000032:analysis / Q000378:metabolism; D002318:Cardiovascular Diseases / Q000097:blood* / Q000453:epidemiology*; D019040:E-Selectin / Q000097:blood; D004730:Endothelium, Vascular / Q000502:physiology*; D005230:Fatty Acids, Nonesterified / Q000097:blood*; D005260:Female; D006442:Glycated Hemoglobin / Q000032:analysis / Q000378:metabolism; D006801:Humans; D007328:Insulin / Q000097:blood; D018799:Intercellular Adhesion Molecule-1 / Q000097:blood; D008297:Male; D009195:Peroxidase / Q000097:blood*; D017395:Plasminogen Activator Inhibitor 1 / Q000097:blood*; D012016:Reference Values; D019010:Vascular Cell Adhesion Molecule-1 / Q000097:blood
D001786:Blood Glucose; D019040:E-Selectin; D005230:Fatty Acids, Nonesterified; D006442:Glycated Hemoglobin; D007328:Insulin; D018799:Intercellular Adhesion Molecule-1; D009195:Peroxidase; D017395:Plasminogen Activator Inhibitor 1; D019010:Vascular Cell Adhesion Molecule-1