Characterization of carotenoid, vitamin A, and α-tocopheral levels in human lung tissue and pulmonary macrophages

Increasing evidence suggests that β-carotene, retinol (vitamin A), and α-tocopheral (vitamin E) may have important protective effects in the lung. However, surprisingly little is known about their storage and metabolism in human lung. Levels of β-carotene, retinol, and α-tocopherol in human lung tissues and bronchoalveolar lavage (BAL) cells were determined with reverse- phase high-pressure liquid chromatography (HPLC). Fresh lung tissue, serum, and dietary questionnaires were obtained from 21 patients undergoing open lung surgery, and BAL cells from 12 of these patients. Dietary and serum levels of carotenoids, β-carotene, retinol, and α-tocopherol were consistent with previously reported values. Lung tissue levels of total carotenoids, β-carotene, retinol, and α-tocopherol were respectively 0.34 ± 0.36 μg/g, 0.13 ± 0.27 μg/g, 0.15 ± 0.06 μg/g, and 9.60 ± 4.86 μg/g tissue. Levels of these nutrients were also measured in BAL cells to establish potential markers for their lung tissue levels. Correlations between serum, BAL-cell, tissue, and dietary levels of the nutrients were determined. Lung tissue levels of total carotenoids, β-carotene, and α- tocopherol, but not retinol, correlated well with their serum levels. Lung tissue levels of retinol and α-tocopherol correlated with their BAL-cell levels. These studies demonstrate quantifiable levels of retinol, α- tocopherol, and total carotenoids or β-carotene in human lung tissue and BAL cells, and show that serum and/or BAL-cell levels of these nutrients can potentially be used to predict their lung tissue levels.