Lipidosis of Pulmonary Macrophages in the Dystrophic Hamster

Abstract

Lavaged pulmonary macrophages of Bio 14.6 myopathic hamsters were compared with those from Bio F₁B controls. Enlarged foamy macrophages were prevalent in the dystrophic strain. Lipidosis within this cell population was confirmed by morphologic and chemical analyses. The percentage of lipid-positive cells obtained from Bio 14.6 hamsters was three times greater than from control animals, but the total number of macrophages recovered from the lungs of dystrophic animals was approximately one-third lower compared to controls. Nearly two-thirds of the lipid-positive cells from the dystrophic strain were moderately to excessively engorged, whereas a similar percentage of the positive cells from control animals contained only sparse lipid inclusions. Qualitative ultrastructural differences were not observed between strains, but engorged macrophages of the dystrophic strain typically showed a predominance of lipid droplets with grey homogeneous material, crowded cytoplasmic organelles, and fewer primary lysosomes. Lipid analyses showed an 85% increase of total cellular lipids, a 486% increase of cholesteryl esters in neutral lipids, and increased 18:1 fatty acids in total lipids and the cholesteryl esters in cells from the Bio 14.6 strain. The etiology of the lipid excess has not been determined, but elevated chylomicrons and reduced alpha-lipoprotein values were observed in the serum of the dystrophic strain.