Prickly pear changes 111indium–LDL and 111indium–HDL platelet binding Correlating to improvement of platelet function in hypercholesterolemia
Keywords:LDL–binding, 111Indium, radiolabeling, ß–thromboglobulin (ßTG), prickly pear, platelet function, ADP–induced aggregation.
Prickly pear consumption has shown beneficial effects on lipid metabolism and platelet function. Platelet low–density lipoprotein (LDL) and high–density lipoprotein (HDL) binding plays a key role in regulating the cellular functional activity. We therefore examined the role of prickly pear consumption on 111Indium (111In)–LDL and 111In–HDL platelet binding in familial hypercholesterolemia (FH). Low–density (LDL) and high–density lipoproteins (HDL) were isolated by ultracentrifugation and subsequently radiolabeled with 111In. The in–vitro binding of the radiolabel onto platelets was investigated in 14 patients with heterozygous FH. One month of dietary intervention was followed by a 2–months consumption of prickly pear. Dietary intervention improved Bmax (111In–LDL but not 111In–HDL) and had no effect on platelet function. Consumption of prickly pear, in contrast, resulted in a significantly increased 111In–LDL and 111In–HDL–binding by platelets which was associated with a significant decrease in platelet activity as determined via ADP–induced platelet aggregation, ß–thromboglobulin and 11–dehydro–thromboxane B2. These findings demonstrate that 111In–LDL and 111In–HDL specific binding sites on platelets which are lower in heterozygous FH can be upregulated by regular prickly pear consumption. This alteration is paralleled by a deactivation of platelets. The underlying mechanism still remains to be elucidated.