Genetic and functional characteristics of the human in vivo LRP1/A2MR receptor suggested as a risk marker for Alzheimer's disease and other complex (degenerative) diseases.

LDL receptor-related protein/alpha2-macroglobulin receptor (LRP1/A2MR) a multiligand receptor is considered as not only being a possible risk factor of neurodegenerative diseases like Alzheimer's disease but also as determining the progression of other complex diseases like atherosclerosis and cancer. Although a large number of in vitro studies have highlighted its functional importance, as yet not enough is known about the clinical importance of the genetic background of LRP1 in human diseases. The aim of this ex vivo/in vivo study of 448 subjects was to present data on genetic LRP1 variants of healthy European Caucasians from Central Germany. Genotype-dependent LRP1 expression was analyzed in a representative subgroup (gene expression: n = 127, protein expression: n = 44). These data were evaluated in comparison to other published clinical LRP1 studies. For 15 functionally interesting genetic variants the genotype and allele distributions of the German Caucasians were presented in relation to their in vivo LRP1 gene and protein expression. A direct influence of the LRP1 promoter polymorphism c.1-25C>G on the human in vivo LRP1 expression level was demonstrated. In an analysis of 48 further studies genomic and functional results were evaluated. The analysis especially on Alzheimers's disease partly highlighted contradictory results, but suggested that ethnic as well as genomic characteristics determine LRP1 expression and must be considered in clinical investigations on human LRP1.