Influence of age and dietary fish oil on plasma soluble adhesion molecule concentrations

Soluble forms of intercellular adhesion molecule-1, vascular cell adhesion molecule-1 and E-selectin (termed sICAM-1, sVCAM-1 and sE-selectin respecti vely) are found in the plasma, and are elevated during inflammatory conditi ons in which there is increased expression of the cellular forms of the mol ecules on endothelial and other cells. sICAM-1, sVCAM-1 and sE-selectin con centrations were measured in the plasma of 140 healthy Caucasian subjects a ged between 18 and 75 years (100 males/40 females). sICAM-1 concentrations varied between 59.9 and 299.7 ng/ml (median 150 ng/ml), sVCAM-1 concentrati ons varied between 222.8 and 1672.9 ng/ml (median 662 ng/ml) and sE-selecti n concentrations varied between 12.4 and 90.3 ng/ml (median 45.5 ng/ml). Th ere were significant positive linear correlations between age and the plasm a concentrations of sICAM-1 (r = 0.580; P < 0.001) and sVCAM-1 (r = 0.392; P < 0.001), which were retained when the effects of gender, body mass index and fasting plasma triacylglycerol and total cholesterol concentrations we re controlled for. The significant positive linear correlation between age and the plasma concentration of sE-selectin (r = 0.234; P = 0.027) was lost when other variables were controlled for. Male subjects < 40 years of age had significantly lower plasma concentrations of both sICAM-1 and sVCAM-1 t han males > 55 years of age (both P < 0.001), but the difference in plasma sE-selectin concentrations between the age groups did not reach significanc e (P = 0.073). Subgroups of 16 males aged < 40 years and 12 elderly subject s (> 55 years of age) participated in a doubled-blind, placebo-controlled s tudy of fish oil supplementation over 12 weeks. The level of eicosapentaeno ic acid in plasma phospholipids did not change with placebo supplementation , but was significantly increased with fish oil supplementation in both you ng male and elderly subjects (median increase 200%). sICAM-1, sVCAM-1 and s E-selectin concentrations were unaffected by supplementation with placebo i n either young male or elderly subjects, sICAM-1 concentrations were unaffe cted by fish oil supplementation. sE-selectin concentrations were significa ntly increased by fish oil supplementation in young males (P = 0.043; media n increase 38%), but fish oil tended to decrease plasma sE-selectin concent rations in the elderly subjects (P = 0.075), with a median decrease of 11%. sVCAM-1 concentrations were unaffected by fish oil supplementation in youn g males. Fish oil supplementation significantly decreased plasma sVCAM-1 co ncentrations in the elderly subjects (P = 0.043), with a med lan decrease o f 20% (range 16-60%). These observations suggest that fish oil decreases en dothelial activation in elderly subjects.