Alpha- and gamma-tocopherol in plasma, red blood cells, and platelets during plasma exchange

The effect of a rapid reduction of plasma lipoproteins on the alpha- and gamma-tocopherol levels in plasma, erythrocytes, and platelets was studied. Sixteen successive plasma exchange procedures performed weekly in an adult with heterozygous familial hypercholesterolemia were evaluated. Plasma exchange was done by intermittent flow centrifugation, exchanging one plasma volume against a 4% human albumin solution. Plasma exchange reduced in plasma alpha-tocopherol from 41.5 +/- 8.9 to 23.6 +/- 4.8 mumol/L and gamma-tocopherol from 4.9 +/- 4.1 to 2.4 +/- 2.1 mumol/L, without changing their ratios to total lipids. It diminished alpha-tocopherol in platelets from 12.97 +/- 4.37 to 10.03 +/- 1.78 mumol/10(13) cells and gamma-tocopherol from 1.43 +/- 0.55 to 1.06 +/- 0.41 mumol/10(13) cells, but did not affect erythrocyte tocopherols. The total amount removed per procedure was 47.57 +/- 13.65 mumol for alpha-tocopherol and 4.70 +/- 3.59 mumol for gamma-tocopherol. Plasma exchange increased the number of erythrocytes from 3.67 +/- 0.10.10(12) to 4.05 +/- 0.13.10(12) cells/L, without affecting their volume. Platelet count did not change, but mean platelet volume decreased from 7.7 +/- 0.5 to 6.9 +/- 0.5 fl and platelet distribution width from 15.1 +/- 0.4 to 14.9 +/- 0.5. Thus, plasma exchange reduces plasma alpha- and gamma-tocopherol to the same extent as total lipids, and decreases these tocopherols in circulating platelets, along with a reduction in platelet size and, compared to the change in erythrocyte count, a fall of platelet number.(ABSTRACT TRUNCATED AT 250 WORDS)