[In vivo flow of autologous radioactively labeled low-density lipoproteins (LDL) in human blood vessels].

Following 123I-labelling and reinjection of autologous low-density lipoproteins (LDL) to patients with clinically manifest atherosclerosis and/or hyperlipoproteinaemia (HLP), an investigation was carried out of whole body kinetics and local kinetics over atherosclerotic lesions and areas of increased LDL entry identified by "hot spots" in the 123I-LDL scintigram. In patients with HLP the number and frequency of "hot spots" was higher than in normolipaemics. The time course of 123I-LDL influx into atherosclerotic lesion sites until scintigraphic visualization of "hot spots" exhibited three different types of LDL uptake among the patients. In the majority of patients LDL kinetics was characterized by entry into the vessels with the maximal radioactivity measured as early as within 60 minutes after reinjection. In some patients maximal radioactivity over lesion sites was discovered after 20 hours or even later. Morphological evaluation revealed that in comparison to control tissue, fatty streaks and lipid lesions show by far the highest 123I-LDL accumulation. Ex vivo measurement of the deposition of 125I-LDL in de- and re-endothelialized rabbit aortic segments exhibited a significantly (p less than 0.01 - p less than 0.001) higher 125I-LDL retention as compared with endothelialized segments (after i.v.-injection).