Effect of different lipid apheresis methods on plasma polyunsaturated fatty acids

Lipoprotein apheresis has been shown to improve the cardiovascular outcome in patients with atherosclerotic disease and therapy-refractory hypercholesterolemia or elevated lipoprotein (a) (Lp(a)). An elevated intake of omega-3 polyunsaturated fatty acids such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) has also been associated with a reduced cardiovascular risk. However, until now only little is known about the effect of apheresis treatment on the levels of omega-6 and omega-3 polyunsaturated fatty acids (n-6 PUFA and n-3 PUFA) in patients. Using gas chromatography (GC) the present study analyzed the content of n-6 and n-3 PUFA as well as saturated fatty acids and monounsaturated fatty acids in the plasma of 20 patients with hyperlipidemia undergoing regular lipoprotein apheresis procedures in direct pre- and post-therapy measurements. Lipoprotein apheresis uniformly reduced the concentrations of arachidonic acid (AA), EPA and DHA fatty acids analyzed in the plasma. However, the three different apheresis methods analyzed (heparin precipitation, membrane filtration and direct absorption) had different effects on the fatty acid profile in the plasma. We found that heparin precipitation and direct absorption apheresis procedures led to a significant decrease of plasma n-3 and n-6 PUFA by 40-50%. In contrast, patients undergoing membrane filtration apheresis, levels pre- and post-apheresis did not change significantly, with AA and EPA being only reduced by approximately 10% while levels of DHA were maintained pre- and post-apheresis. In contrast, total triglyceride levels were lowered most potently by membrane filtration apheresis. In summary, heparin precipitation and direct absorption apheresis approaches significantly lowered polyunsaturated fatty acids in plasma, while membrane filtration did not. This might have implications for cardiovascular and inflammatory risk/benefit profiles associated with n-6 and n-3 PUFA levels in the body.