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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.
Insights
Pulmonary macrophages in dystrophic hamsters exhibit significant lipidosis, with enlarged foamy cells containing excess lipids. This suggests a cellular lipid metabolism disorder contributing to the myopathy in Bio 14.6 hamsters.
Area of Science:
- Cell Biology
- Biochemistry
- Animal Models
Background:
- Pulmonary macrophages play a role in lipid metabolism and immune response.
- Myopathic hamsters (Bio 14.6 strain) exhibit a genetic disorder affecting muscle tissue.
Purpose of the Study:
- To investigate the characteristics of pulmonary macrophages in Bio 14.6 myopathic hamsters compared to controls.
- To determine if lipid accumulation (lipidosis) occurs in these macrophages and to quantify lipid content.
Main Methods:
- Pulmonary macrophages were lavaged from Bio 14.6 myopathic hamsters and Bio F1B control hamsters.
- Morphologic, chemical, and ultrastructural analyses were performed on the macrophages.
- Lipid content, including total lipids and cholesteryl esters, was quantified.
Main Results:
- Enlarged, foamy macrophages with prevalent lipidosis were observed in dystrophic hamsters.
- Bio 14.6 hamsters had three times more lipid-positive macrophages but one-third fewer total macrophages.
- Macrophages from dystrophic hamsters showed significantly increased total cellular lipids (85%) and cholesteryl esters (486%).
Conclusions:
- Bio 14.6 myopathic hamsters exhibit significant pulmonary macrophage lipidosis, characterized by enlarged foamy cells with excessive lipid accumulation.
- The observed lipid abnormalities in macrophages may be linked to systemic lipid metabolism dysregulation, as indicated by serum chylomicron and alpha-lipoprotein levels.
- Further research is needed to elucidate the etiology of this lipid excess in the context of muscular dystrophy.