BACKGROUND: C-reactive protein (CRP) has been proven to facilitate endothelial injury via reduced NO production. Endothelial microparticles (EMPs) have emerged as a novel marker of endothelial injury. METHODS: In vitro cultured human umbilical vein endothelial cells (HUVECs) were incubated with CRP (20 mg/l) for 24 h. The numbers of EMPs with CD31- and CD51-positive staining were assessed flow-cytometrically, and NO production was measured using the Griess reaction in the presence or absence of tetrahydrobiopterin (BH(4)), respectively. RESULTS: The number of EMPs was significantly increased in HUVECs stimulated by CRP compared with the control group and, in parallel, NO production was decreased (p < 0.05). In the presence of CRP, pretreatment with BH(4) decreased EMP counts and restored NO production to baseline levels (p < 0.05) while pretreatment with 2,4-diamino-6-hydroxypyrimidine (DAHP), a BH(4) synthesis inhibitor, further prompted EMP formation and decreased NO production (p < 0.05). However, adding exogenous BH(4) after pretreatment with DAHP suppressed EMP formation and restored NO production (p < 0.05). CONCLUSIONS: This study demonstrates that CRP induces EMP generation in HUVECs and this effect is, at least in part, related to impaired BH(4)-dependent NO production. Augmented EMP generation in HUVECs is suggested as a novel potential mechanism contributing to the pathogenesis of vascular injury related to CRP.
BACKGROUND:C-reactive protein (CRP) has been proven to facilitate endothelial injury via reduced NO production. Endothelial microparticles (EMPs) have emerged as a novel marker of endothelial injury. METHODS: In vitro cultured human umbilical vein endothelial cells (HUVECs) were incubated with CRP (20 mg/l) for 24 h. The numbers of EMPs with CD31- and CD51-positive staining were assessed flow-cytometrically, and NO production was measured using the Griess reaction in the presence or absence of tetrahydrobiopterin (BH(4)), respectively. RESULTS: The number of EMPs was significantly increased in HUVECs stimulated by CRP compared with the control group and, in parallel, NO production was decreased (p < 0.05). In the presence of CRP, pretreatment with BH(4) decreased EMP counts and restored NO production to baseline levels (p < 0.05) while pretreatment with 2,4-diamino-6-hydroxypyrimidine (DAHP), a BH(4) synthesis inhibitor, further prompted EMP formation and decreased NO production (p < 0.05). However, adding exogenous BH(4) after pretreatment with DAHP suppressed EMP formation and restored NO production (p < 0.05). CONCLUSIONS: This study demonstrates that CRP induces EMP generation in HUVECs and this effect is, at least in part, related to impaired BH(4)-dependent NO production. Augmented EMP generation in HUVECs is suggested as a novel potential mechanism contributing to the pathogenesis of vascular injury related to CRP.
Authors: Anne M Curtis; Lifeng Zhang; Elizabeth Medenilla; Ming Gui; Patrick F Wilkinson; Erding Hu; Jay Giri; Vijay Doraiswamy; Sampath Gunda; Mark E Burgert; Jonni S Moore; Jay M Edelberg; Emile R Mohler Journal: Cytometry B Clin Cytom Date: 2010-06-11 Impact factor: 3.058
Authors: Anne M Curtis; Jay Edelberg; Rebecca Jonas; Wade T Rogers; Jonni S Moore; Wajihuddin Syed; Emile R Mohler Journal: Vasc Med Date: 2013-07-26 Impact factor: 3.239
Authors: Carmine Savoia; Lidia Sada; Luigi Zezza; Lorenzo Pucci; Francesco Maria Lauri; Alberto Befani; Alessandro Alonzo; Massimo Volpe Journal: Int J Hypertens Date: 2011-09-11 Impact factor: 2.420
Authors: Michael D Brown; Deborah L Feairheller; Sunny Thakkar; Praveen Veerabhadrappa; Joon-Young Park Journal: Vasc Health Risk Manag Date: 2011-08-26