Abstract
Kanazawa et al. and Muraoka et al, reported that cholesterol concentrations of ultra-water-soluble LDLs (UWS-LDL) separated by dialysis from tap-water were higher in cerebral infarction or ischemic heart disease patients than in healthy persons.
In this experiment, internalization into macrophages and cell injury caused by UWS-LDLs obtained from patients with arteriosclerotic disease were investigated.
1) The internalization rates of UWS-LDLs such as proteins, cholesterol esters (CE), triglycerides (TG), free fatty acids (FFA) and free cholesterol (FC) into macrophages were greater than those of native LDL.
2) The internalization rate of UWS-LDLs such as CE and FC into macrophages was enhanced by adding heparin to the medium, although no heparin-related differences were found for protein, TG and FFA.
Thus, we concluded that the metabolic pathway as well as the phagocytic pathway might be the mechanism of internalization of UWS-LDLs into macrophages.
3) The scanning electron microscope findings of macrophages did not change after incubation with native LDLs and macrophages at 37°C. However, after 2 hours of incubating UWS-LDLs and macrophages, cell swelling and rough change of the cell centrum due to internalization of UWS-LDLs were observed. After 6 hours, cell injury was more advanced and the central part of the cells were destroyed. Finally, floating cells were observed in the medium.
Conclusion:
The concentration of UWS-LDL-cholesterol was closely related to the incidence of arteriosclerotic disease. We also confirmed that UWS-LDLs were easily internalized into macrophages and that they injured the cells.
Thus, we feel that this study on UWS-LDLs was very important to clarify the causes of arteriosclerosis.
