Intraplatelet miRNA-126 regulates thrombosis and its reduction contributes to platelet inhibition.

AIMS: MicroRNA-126 (miR-126), one of the most abundant microRNAs in platelets, is involved in the regulation of platelet activity and the circulating miR-126 is reduced during antiplatelet therapy. However, whether intraplatelet miR-126 plays a role in thrombosis and platelet inhibition remains unclear. METHODS AND RESULTS: Here, using tissue-specific knockout mice, we reported that the deficiency of miR-126 in platelets and vascular endothelial cells significantly prevented thrombosis and prolonged bleeding time. Using chimeric mice, we identified that the lack of intraplatelet miR-126 significantly prevented thrombosis. Ex vivo experiments further demonstrated that miR-126-deficient platelets displayed impaired platelet aggregation, spreading and secretory functions. Next, miR-126 was confirmed to target phosphoinositol-3 kinase regulatory subunit 2 (PIK3R2) in platelet, which encodes a negative regulator of the PI3 K/AKT pathway, enhancing platelet activation through activating the integrin αIIbß3-mediated outside-in signaling. After undergoing myocardial infarction (MI), chimeric mice lacking intraplatelet miR-126 displayed reduced microvascular obstruction and prevented MI expansion in vivo. In contrast, overexpression of miR-126 by the administration of miR-126 agonist (agomiR-126) in wild-type mice aggravated microvascular obstruction and promoted MI expansion, which can be almost abolished by aspirin administration. In patients with cardiovascular diseases, antiplatelet therapies, either aspirin alone or combined with clopidogrel, decreased the level of intraplatelet miR-126. The reduction of intraplatelet miR-126 level was associated with the decrease of platelet activity. CONCLUSIONS: Our murine and human data reveal that (i) intraplatelet miR-126 contributes to platelet activity and promotes thrombus formation, and (ii) the reduction of intraplatelet miR-126 contributes to platelet inhibition during antiplatelet therapy.

Effect of proton pump inhibitors versus histamine-2 receptor antagonists on acute kidney injury in septic patients at high risk for developing stress ulcers.

BACKGROUND: To compare the effects of proton pump inhibitor (PPI) and histamine-2 receptor antagonist (H2RA) use on the occurrence of acute kidney injury (AKI) in septic patients at high risk for developing stress ulcers. METHODS: Using the Medical Information Mart for Intensive Care IV version 2.2 database, septic patients with high-risk factors for stress ulcers (i.e., shock, coagulopathy, invasive mechanical ventilation, or chronic liver diseases) were included. Exposures included PPIs and H2RAs within 24 h of intensive care unit (ICU) admission or prior to ICU admission. The primary end point was severe sepsis-associated AKI as defined by the Kidney Disease Improving Global Outcomes criteria stage 3 (KDIGO-3). Propensity score matching (PSM) was performed to balance baseline characteristics. Multivariable Cox proportional hazards regression was used to estimate the effect size. RESULTS: 4731 PPI users and 4903 H2RA users were included. After PSM, there were 1785 pairs exposed to PPIs and H2RAs. In the PSM cohort, the cumulative incident KDIGO-3 rate was higher in the PPI group than in the H2RA group (log-rank test, p = 0.009). Regression analyses showed that PPI exposure [adjusted hazard ratio 1.32, 95% confidence interval (CI) 1.11-1.58, p = 0.002] was associated with incident KDIGO-3 compared with H2RA use. This association remained consistent in sensitivity analyses. Additionally, the PPI group had a higher need for kidney replacement therapy compared with the H2RA group (3.6% vs. 2.1%, P = 0.012). CONCLUSIONS: Among septic patients at high risk for developing stress ulcers, PPI exposure was associated with incident KDIGO-3 AKI compared with H2RA use.