Low molecular weight heparin-induced increase in chylomicron-remnants clearance, is associated with decreased plasma TNF-α level and increased hepatic lipase activity

Abstract

The acute effect of heparin on lipoprotein clearance is well characterized. Yet, the effect of prolonged low-molecular-weight-heparin (LMWH) administration on post-prandial lipemia has remained so far unexplored. Recent reports suggest that LMWH could modify lipid and carbohydrate metabolism by diminishing TNFα-mediated inflammatory response. This, together with the known negative effect of TNF-α on insulin sensitivity, prompted us to hypothesize that LMWH would favorably affect post-prandial lipoprotein disposal. Twenty four patients were given a vitamin A-fat loading meal at the end of 6-week enoxaparin treatment and after 3-month washout period. Post-prandial lipemia was assessed by measuring retinyl-palmitate (RP) during 8hours following the meal. Insulin sensitivity index (ISI), plasma lipolytic activity and plasma TNF-α were measured. Enoxaparin did not impact fasting plasma lipids and lipoproteins levels. Enoxaparin increased RP clearance in the chylomicron remnant (CMR) fraction by 32% (P<0.01). Additionally, enoxaparin decreased plasma TNF-α by 22% (P<0.01), increased hepatic lipase (HL) activity by 81% (P<0.01), along with a 2-fold increase in ISI (P<0.01). The decrease in CMR correlated with the reduction in TNFα and the increase in ISI and HL activity (R=0.48, -0.68, -0.56, respectively, p<0.05). Significant correlations were also found between the reduction in TNFα and both the increase in ISI and increase in HL activity (R=-0.43, -0.54, respectively, P<0.05). The association of the effect on post-prandial metabolism, plasma TNFα level and HL activity during prolonged enoxaparin treatment may support the hypothesis that the beneficial outcome of enoxaparin may possibly be linked to anti-inflammatory and lipase-potentiating impact.