Increased plasma sphingosine-1-phosphate in obese individuals and its capacity to increase the expression of plasminogen activator inhibitor-1 in adipocytes.

Objectives: Concentrations of plasminogen activator inhibitor-1 (PAI-1) are increased in obese individuals. One source of PAI-1 is adipocytes. Hypoxia develops within adipose tissue as it expands, presumably contributing to increased levels of sphingosine-1-phosphate (S1P).