title: Advanced glycation end products elicit externalization of phosphatidylserine in a subpopulation of platelets via 5-HT2A/2C receptors.
abstract: Advanced glycation end products (AGE) are substantially elevated in individuals with diabetes and/or chronic kidney disease (CKD). These patients are at greatly increased risk of cardiovascular events. The purpose of this study was to investigate the novel hypothesis that AGE elicit externalization of the platelet membrane phospholipid phosphatidylserine (PS). This contributes to hemostasis through propagation of the coagulation cascade leading to thrombus formation. Platelet-rich plasma (PRP) was prepared by differential centrifugation, and PS externalization was quantified by a fluorescence-activated cell sorter using annexin V-FITC. Human serum albumin (HSA)-AGE was generated by incubating HSA with glucose for 2, 4, or 6 wk, and total HSA-AGE was assessed by fluorescence intensity. The 2-wk HSA-AGE preparation (0-2 mg/ml) stimulated a concentration-dependent increase in PS externalization in a subpopulation of platelets that was threefold at 2 mg/ml. In contrast, the 4- and 6-wk preparations were maximal at 0.5 mg/ml and fivefold in magnitude. These effects mirrored the change in total HSA-AGE content of the preparations. The PS response was maximal at 10 min and inhibited by the PKC-delta inhibitor rottlerin and the serotonin [5-hydroxytryptamine (5-HT)](2A/2C) receptor antagonist ritanserin in a dose-dependent manner. Moreover, the 5-HT(2A/2C) receptor agonist 1,2,5-dimethoxy-4-iodophenyl-2-aminopropane mimicked the effect of HSA-AGE on PS externalization. These data demonstrate, for the first time, that HSA-AGE stimulates PS externalization in a subpopulation of platelets via the 5-HT(2A/2C) receptor. This may have important consequences for platelet involvement in inflammatory responses and the increased cardiovascular risk observed in individuals with diabetes and/or CKD.
authors.affiliation: Faculty of Medical Sciences, Framlington Place, Newcastle University, Newcastle-Upon-Tyne, UK NE2 4HH.
authors.forename: Yingjie
authors.initials: Y
authors.lastname: Wang
authors.forename: Werner
authors.initials: W
authors.lastname: Beck
authors.forename: Reinhold
authors.initials: R
authors.lastname: Deppisch
authors.forename: Sally M
authors.initials: SM
authors.lastname: Marshall
authors.forename: Nicholas A
authors.initials: NA
authors.lastname: Hoenich
authors.forename: Michael G
authors.initials: MG
authors.lastname: Thompson
mesh_terms: D000098:Acetophenones / Q000494:pharmacology; D000662:Amphetamines / Q000494:pharmacology; D001578:Benzopyrans / Q000494:pharmacology; D001777:Blood Coagulation / Q000187:drug effects; D001792:Blood Platelets / Q000187:drug effects / Q000378:metabolism*; D016022:Case-Control Studies; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism*; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000150:complications / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D017127:Glycation End Products, Advanced / Q000378:metabolism* / Q000494:pharmacology; D006801:Humans; D010718:Phosphatidylserines / Q000378:metabolism*; D015539:Platelet Activation / Q000187:drug effects; D051745:Protein Kinase C-delta / Q000037:antagonists & inhibitors / Q000378:metabolism; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D044402:Receptor, Serotonin, 5-HT2A / Q000187:drug effects / Q000378:metabolism*; D044405:Receptor, Serotonin, 5-HT2C / Q000187:drug effects / Q000378:metabolism*; D051436:Renal Insufficiency, Chronic / Q000097:blood / Q000150:complications / Q000378:metabolism*; D016713:Ritanserin / Q000494:pharmacology; D012702:Serotonin Antagonists / Q000494:pharmacology; D017366:Serotonin Receptor Agonists / Q000494:pharmacology; D012709:Serum Albumin / Q000378:metabolism* / Q000494:pharmacology; D000075462:Serum Albumin, Human; D013997:Time Factors
chemical_list: D000098:Acetophenones; D000662:Amphetamines; D001578:Benzopyrans; D017127:Glycation End Products, Advanced; D010718:Phosphatidylserines; D047428:Protein Kinase Inhibitors; D044402:Receptor, Serotonin, 5-HT2A; D044405:Receptor, Serotonin, 5-HT2C; D012702:Serotonin Antagonists; D017366:Serotonin Receptor Agonists; D012709:Serum Albumin; C109748:advanced glycation end products-human serum albumin; D016713:Ritanserin; C085746:rottlerin; D051745:Protein Kinase C-delta; C015952:4-iodo-2,5-dimethoxyphenylisopropylamine; D000075462:Serum Albumin, Human