The 12th annual European Conference on Vascular Biology.

The 12th annual scientific meeting of the European Vascular Biology Association was held in Gilleleje, Denmark, from April 27 to May 1, 1991, in collaboration with the Scandinavian Society for Atherosclerosis Research. The sessions of the meeting covered two major fields: hyperlipidemias relating to the genetic variability of apolipoprotein B-100 and transendothelial flow of macromolecules. The first session covered several aspects of familial combined hyperlipidemia (FCH). All speakers agreed on the heterogeneous nature of this disease, which appears to include several different metabolic disorders, each with a separate genetic background. Support for one possible candidate gene was found in the studies by James Scott (United Kingdom), showing an association with the restriction fragment length polymorphisms of the A-I-C-III-A-IV gene cluster. Among the underlying mechanisms for FCH, Ronald Krauss (Berkeley, Calif.) mentioned the possibilities of associations between FCH and heterozygous lipoprotein lipase deficiency, cholesterol hydrolase deficiency, and an upregulation of apolipoprotein B expression in liver cells. One of the characteristics of FCH is related to the low density lipoprotein (LDL) particle size distribution. FCH is often associated with the so-called type B LDL pattern, which is characterized by small, probably more atherogenic LDL particles. The type B LDL pattern appears at least in part to be genetically determined. Patients with FCH have not only small LDL particles but also frequently elevated very low density lipoprotein and intermediate density lipoprotein. A role for these lipoproteins in atherogenesis was suggested from the studies by Borge Nordestgaard (Denmark) on the uptake and deposition of lipoproteins in the rabbit aorta. His data suggest that the rate of efflux is closely and negatively related to particle size, with much lower rates of efflux for larger particles. Thus, although the influx of larger particles is also lower, a net accumulation of the larger particles, i.e., very low density lipoprotein and intermediate density lipoprotein, would follow.