VITAMIN-E-DEFICIENCY AND LIPOPEROXIDATION DURING ADULT RESPIRATORY-DISTRESS SYNDROME

Vitamin E (Vit E) is an important component of the lung's defense against oxidant injury. The aim of this study was to determine a) if adult respiratory distress syndrome (ARDS) was associated with a decrease in Vit E plasma level linked to an enhancement of plasma lipoperoxidation, and b) if this Vit E deficiency might be explained by malnutrition and/or a consumption defect. Vit E, lipoperoxides (LP), total lipids, and fatty acid plasma levels were measured in 12 patients with ARDS (PaO2 ≤60 torr with FIO2 0.6 on mechanical ventilation). At the onset of ARDS (T0), the decrease in Vit E plasma level was significant (p < .001) 7.73 ± 0.54 (n = 12) vs. 11.46 ± 0.55 mg/L (n = 7) in the control group (healthy subjects breathing room air). A significant (p < .05) increase in LP was simultaneously observed (4.12 ± 0.35 [n = 12] vs. 2.94 ± 0.30 nmol/ml [n = 17]) in the control group. At T0, LP were inversely correlated with Vit E plasma levels (r = .78, p < .01). Vit E deficiency was associated with low levels of total plasma lipids (3.68 ± 0.25 g/L) and plasma cholesterol (0.97 ± 0.07 g/L). Thus, the Vit E/total lipids ratio (2.18 ± 0.17 mg/g) was always above the accepted normal limit value for this ratio (0.8 mg/g). Significant decreases in essential fatty acid and linoleic acid (p < .01) and arachidonic acid (p < .05); and a significant (p < .05) increase in the oleic/linoleic acid ratio of 1.42 ± 0.16 vs. 0.91 ± 0.51 in the control group (n = 18) were simultaneously observed. During the 24 h after ARDS onset (n = 9), a significant decrease in LP was observed; i.e., -36% (p < .01) 6 h after ARDS onset, to -24% (p < .05) at 12 and 24 h, associated with a slight decrease in Vit E plotted against time, T0, 12, and 24 h after ARDS onset (Y = -0.03X + 7.34, p < .001) without any significant change in the oleic/linoleic acid ratio. We concluded that a) ARDS was associated with Vit E deficiency and enhancement of plasma lipoperoxidation; b) the low basal values of Vit E were linked to the low cholesterol and total lipid plasma levels, probably as a consequence of malnutrition; and c) during the course of ARDS, a significant Vit E plasma level decrease was observed, either as a consequence of increased utilization or as a consequence of decreased absorption.