ENHANCED RESISTANCE TO OXIDATION OF LOW-DENSITY LIPOPROTEINS AND DECREASED LIPID PEROXIDE FORMATION DURING BETA-CAROTENE SUPPLEMENTATION INCYSTIC-FIBROSIS

We investigated the effect of correcting beta-carotene deficiency in c ystic fibrosis (CF) patients on two parameters of lipid peroxidation: The resistance to oxidation of low density lipoprotein (LDL) was measu red by the lag time preceding the onset of conjugated diene formation during exposure to copper(II) ions, and lipid peroxide formation was q uantitated by malondialdehyde concentrations in plasma (TBA/HPLC metho d). Simultaneously, alpha-tocopherol and beta-carotene concentrations were determined in LDL and in plasma. Thirty-four CF patients were inv estigated before and after 3 months of oral beta-carotene supplementat ion. beta-carotene concentrations increased (p < 0.0001) in plasma (me an +/- SD) (0.09 +/- 0.06 vs. 1.07 +/- 0.86 mu mol/l) and in LDL (0.02 +/- 0.02 vs. 0.31 +/- 0.28 mol/mol), without significant changes in a lpha-tocopherol, either in plasma (24.7 +/- 5.9 vs. 25.4 +/- 7.6) or i n LDL (8.47 +/- 2.95 vs. 9.05 +/- 4.13). Lag times, being shorter (p < 0.05) in patients than in controls, increased from 48.5 +/- 21.3 to 6 9.1 +/- 27.9 min (p < 0.001) and plasma MDA concentrations, being grea ter (p < 0.0001) in patients than in controls, decreased from 0.95 +/- 0.32 to 0.61 +/- 0.15 mu mol/l (p < 0.0001). At 3 months, lag times a nd MDA concentrations did not any longer differ between patients and c ontrols. These data suggest that excess lipid peroxidation occurring i n beta-carotene deficiency can be limited and normalized during effici ent beta-carotene supplementation in CF patients.