Endothelial microparticles increase in mitral valve disease and impair mitral valve endothelial function

Abstract

(HMVECs) were treated with EMPs. The phosphorylation of Akt and endothelial nitric oxide synthase (eNOS), the association of eNOS and heat shock protein 90 (HSP90), and the generation of nitric oxide (NO) and superoxide anion (O2˙Ϫ) were measured. EMPs were increased significantly in patients with mitral valve disease compared with those in healthy subjects. EMPs were negatively correlated with mitral valve area in patients with isolated mitral stenosis. EMPs were significantly higher in the group with severe mitral regurgitation than those in the group with mild and moderate mitral regurgitation. Furthermore, EMPs were decreased dramatically in both Akt and eNOS phosphorylation and the association of HSP90 with eNOS in HMVECs. EMPs decreased NO production but increased O2˙Ϫ generation in HMVECs. Our data demonstrated that EMPs were significantly increased in patients with mitral valve disease. The increase of EMPs can in turn impair HMVEC function by inhibiting the Akt/eNOS-HSP90 signaling pathway. These findings suggest that EMPs may be a therapeutic target for mitral valve disease. endothelial microparticles; mitral valve; nitric oxide; endothelial nitric oxide synthase; heat shock protein 90

Microparticles from Patients with the Acute Coronary Syndrome Impair Vasodilatation by Inhibiting the Akt/eNOS-Hsp90 Signaling Pathway

“…At the end of the MP incubation period, the supernatant was used to determine NO generation using an NO detection kit (Nanjing Jiancheng Bioengineering Institute, Nanjing, China). Aortic samples were dried and weighed, and NO generation was reported as nanomoles per milligram protein [23]. …”

“…After washing, the aortic proteins were harvested and immunoblots performed as previously described [23]. Antibodies to Akt (Cell Signaling Technology, Beverly, Mass., USA), phosphorylated Akt (Cell Signaling Technology), endothelial NO synthase (eNOS; Santa Cruz Biotechnology, Santa Cruz, Calif., USA), eNOS phosphorylated at Ser 1177 (Cell Signaling Technology) and β-actin (Cell Signaling Technology) were used for Western blot analysis.…”

“…The eNOS immunocomplex was mixed with Laemmeli buffer, heated (95°C, 5 min), mixed and stored on ice until it was fractionated. The separated proteins were immunoblotted for eNOS and heat shock protein 90 (Hsp90; Santa Cruz Biotechnology), as previously described [23]. …”

“…Blood samples were centrifuged (11,000 g , 2 min, 4°C) to obtain platelet-poor plasma; 50 μl of platelet-poor plasma were incubated with both 5 μl of anti-CD31-PE and 5 μl of anti-CD41-FITC or CD14-FITC (their corresponding isotypes were used as controls; Beckman Coulter) at room temperature for 30 min [23]. Before the sample was analyzed, 50 μl of flow count calibrator beads (Beckman Coulter) were added to the antibody-labeled tubes.…”

Microparticles: A Novel Player in Cardiovascular Diseases

“…In such patients, the higher number of circulating MPs may contribute to the progression of atherosclerotic disease and enhanced cardiovascular risk [16]. In patients with atrial fibrillation, the secretion of endothelial MPs could play a role in maintaining the prothrombotic and inflammatory process [17]. Interestingly, it has been shown that the level of MPs declines after the restoration of sinus rhythm [18].…”