Assessment of functional low-density-lipoprotein receptors on lymphocytes by a simplified method using culture medium with lipoprotein-free fetal calf serum and pravastatin

Familial hypercholesterolemia (FH), a disorder that results in primary hypercholesterolemia and premature atherosclerosis, is caused by inherited abnormalities in the gene encoding the receptor for LDL. When mitogen-stimulated lymphocytes are cultured in a lipid-depleted medium, the suppression of endogenous sterol synthesis by inhibitors of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase prevents proliferation, since there is neither an exogenous nor an endogenous source of cholesterol. Exogenous LDL can provide sufficient cholesterol for the synthesis of new cell membranes when HMG-CoA reductase activity is blocked. Cuthbert et al. developed a method to identify LDL receptor defects utilizing peripheral blood lymphocytes in a culture medium with mevinolin, a specific inhibitor of HMG-CoA reductase and lipoprotein-free human plasma to supply nonspecific growth factors. In this study, we have substituted pravastatin for mevinolin and lipoprotein-deficient fetal calf serum (LDFCS) for human plasma to assess LDL receptor function of lymphocytes.