BIOCHEMICAL ANALYSES OF BRONCHOALVEOLAR LAVAGE FLUIDS OF HEALTHY HUMAN VOLUNTEER SMOKERS AND NON-SMOKERS

Abstract

Analyses were made of the protein, carbohydrate, lipid and K composition of lavage fluids obtained from healthy volunteers in an effort to establish normal values for content and variability. Transnasal fiberoptic bronchoscopy with pulmonary lavage of the right middle lobe or lingula was performed in 26 volunteers (12 smokers and 14 nonsmokers). Biochemical anaylses were subsequently made of cell-free supernates. The total protein concentration of the original lavage fluid ranged from 31-136 .mu.g/ml. Electrophoretic patterns were similar to those for human serum. Fifty-fold lavage concentrates contained very low concentrations Ig[immunogloblin]G and IgA and no detectable IgM or .alpha.2-macrogoplobulin. The lavage carbohydrate concentration ranged from 3.8-21.2 .mu.g/ml of original fluid. Approximately 4/5 of this carbohydrate was of MW less than 10,000 daltons and 1/5 of this fraction was free glucose. Polar lipid (10.9-161.3 .mu.g/ml original fluid) was present in amounts slightly less than that of nonpolar lipid (25.3-325.0 .mu.g/ml). Lipid P concentrations indicated that a substantial portion of the polar lipid fraction was composed of glycolipid and polar lipids not containing P. Further analyses showed that approximately 84% of the total phospholipid was phosphatidylcholine, composed primarily of palmitic acid (72.5% of total fatty acid). Substantial amounts of phosphatidylglycerol were also present (12.4% of total phospholipid). Smaller amounts of diphosphatidylglycerol, phosphatidylinositol, phosphatidylethanolamine, phosphatidic acid and phosphatidylserine were represented in most samples. Comparisons of serum and lavage fluid K, glucose and albumin concentrations as normalization factors indicated quite good agreement despite the widely different nature of those 3 lavage constituents. Lavage fluid samples from smokers contained significantly lower ratios of lipid P to protein and lower albumin normalization values than those of nonsmokers, but otherwise were not significantly different. Lavage biochemical analyses may be of value in understanding the biology and function of lavage cells and secretions. The data are also useful as a basis for assessing the clinical, diagnostic and investigative usefulness of such analyses in the documentation and study of pulmonary disease.