Dll4 Suppresses Transcytosis for Arterial Blood-Retinal Barrier Homeostasis.

RATIONALE: Central nervous system has low vascular permeability by organizing tight junction (TJ) and limiting endothelial transcytosis. While TJ has long been considered to be responsible for vascular barrier in central nervous system, suppressed transcytosis in endothelial cells is now emerging as a complementary mechanism. Whether transcytosis regulation is independent of TJ and its dysregulation dominantly causes diseases associated with edema remain elusive. Dll4 signaling is important for various vascular contexts, but its role in the maintenance of vascular barrier in central nervous system remains unknown. OBJECTIVE: To find a TJ-independent regulatory mechanism selective for transcytosis and identify its dysregulation as a cause of pathological leakage. METHODS AND RESULTS: We studied transcytosis in the adult mouse retina with low vascular permeability and employed a hypertension-induced retinal edema model for its pathological implication. Both antibody-based and genetic inactivation of Dll4 or Notch1 induce hyperpermeability by increasing transcytosis without junctional destabilization in arterial endothelial cells, leading to nonhemorrhagic leakage predominantly in the superficial retinal layer. Endothelial Sox17 deletion represses Dll4 in retinal arteries, phenocopying Dll4 blocking-driven vascular leakage. Ang II (angiotensin II)-induced hypertension represses arterial Sox17 and Dll4, followed by transcytosis-driven retinal edema, which is rescued by a gain of Notch activity. Transcriptomic profiling of retinal endothelial cells suggests that Dll4 blocking activates SREBP1 (sterol regulatory element-binding protein 1)-mediated lipogenic transcription and enriches gene sets favorable for caveolae formation. Profiling also predicts the activation of VEGF (vascular endothelial growth factor) signaling by Dll4 blockade. Inhibition of SREBP1 or VEGF-VEGFR2 (VEGF receptor 2) signaling attenuates both Dll4 blockade-driven and hypertension-induced retinal leakage. CONCLUSIONS: In the retina, Sox17-Dll4-SREBP1 signaling axis controls transcytosis independently of TJ in superficial arteries among heterogeneous regulations for the whole vessels. Uncontrolled transcytosis via dysregulated Dll4 underlies pathological leakage in hypertensive retina and could be a therapeutic target for treating hypertension-associated retinal edema.

Trends in skin prick test according to seasons: Results of a Korean multi-center study.

OBJECTIVE: Allergy is a very common condition. Allergic disease is highly affected by environmental changes. Conditions of the four seasons can change dramatically in Republic of Korea (ROK). To assess changes in rates of aeroallergen positivity according to seasons and environmental factors (temperature, humidity, and precipitation). MATERIALS: A total of 20 hospitals were selected based on population distribution in ROK. A skin prick test (SPT) panel comprising 55 aeroallergens was distributed to 18 hospitals for a prospective study. Results from SPTs done in 2006 and 2010 were collected and analyzed retrospectively from 20 hospitals and 2014/2015 SPT (from June 2014 to May 2015) results from 18 hospitals were collected prospectively. RESULTS: We compared allergen-positive rates among seasons. Positive test rates for several pollens and house dust mites increased significantly in spring and fall. Pollens positive rate varied significantly according to temperature, precipitation, and humidity while mite allergens were less susceptible to environment. CONCLUSION: There are four distinct seasons in ROK. The positivity of pollen allergens were especially affected by temperature and precipitation in spring. House dust mites were less affected by seasons, temperature, precipitation, and humidity less than pollen. Therefore, regular follow-up and re-evaluation of allergic test are essential considering changes of seasons and environment for acceptable diagnosis and treatment.

Effectiveness and safety of non-vitamin K antagonist oral anticoagulants in octogenarian patients with non-valvular atrial fibrillation.

BACKGROUND AND OBJECTIVE: Elderly patients with atrial fibrillation (AF) are known to have a high risk of stroke and bleeding. We investigated the effectiveness and safety of non-vitamin K antagonist oral anticoagulants (NOACs) in octogenarian patients with non-valvular AF compared with warfarin. METHODS: A total of 687 octogenarian patients with AF who were administered NOACs (n = 403) or warfarin (n = 284) for stroke prevention between 2012 and 2016 were included. Thromboembolic (TE) events (stroke or systemic embolism), major bleeding events, and all-cause death were analyzed. RESULTS: The NOACs group (age 83.4±3.2 years, women 52.4%, CHA2DS2-VASc score 5.0±1.8) comprised 141 dabigatran, 158 rivaroxaban, and 104 apixaban users. Most patients from the NOACs group had been prescribed a reduced dose of medication (85.6%). During 14±18 months of follow-up periods, there were 19 TE events and 18 major bleeding events. Patients with NOAC showed a lower risk of TE (1.84 vs. 2.71 per 100 person-years, hazard ration [HR] 0.134, 95% confidence interval [CI] 0.038-0.479, P = 0.002), major bleeding (1.48 vs. 2.72 per 100 person-years, HR 0.110, 95% CI 0.024-0.493, P = 0.001), and all-cause death (2.57 vs. 3.50 per 100 person-years, HR 0.298, 95% CI 0.108-0.824, P = 0.020). CONCLUSION: In octogenarian Asian patients with AF, NOACs might be associated with lower risks of thromboembolic events, major bleeding, and all-cause death than warfarin. Although most patients had received reduced doses, on-label use of NOACs was effective and safe.

Characteristics, Outcomes, and Treatment of Heart Failure With Improved Ejection Fraction.

Background Many patients with heart failure ( HF ) with reduced ejection fraction ( HF r EF ) experience improvement or recovery of left ventricular ejection fraction ( LVEF ). Data on clinical characteristics, outcomes, and medical therapy in patients with HF with improved ejection fraction (HFiEF) are scarce. Methods and Results Of 5625 consecutive patients hospitalized for acute HF in the KorAHF (Registry [Prospective Cohort] for Heart Failure in Korea) study, 5103 patients had baseline echocardiography and 2302 patients had follow-up echocardiography at 12 months. HF phenotypes were defined as persistent HF r EF ( LVEF ≤40% at baseline and at 1-year follow-up), HF i EF ( LVEF ≤40% at baseline and improved up to 40% at 1-year follow-up), HF with midrange ejection fraction (LVEF between 40% and <50%), and HF with preserved ejection fraction ( LVEF ≥50%). The primary outcome was 4-year all-cause mortality from the time of HF i EF diagnosis. Among 1509 HF r EF patients who had echocardiography 1 year after index hospitalization, 720 (31.3%) were diagnosed as having HF i EF . Younger age, female sex, de novo HF , hypertension, atrial fibrillation, and ß-blocker use were positive predictors and diabetes mellitus and ischemic heart disease were negative predictors of HF i EF . During 4-year follow-up, patients with HF i EF showed lower mortality than those with persistent HF r EF in univariate, multivariate, and propensity-score-matched analyses. ß-Blockers, but not renin-angiotensin system inhibitors or mineralocorticoid receptor antagonists, were associated with a reduced all-cause mortality risk (hazard ratio: 0.59; 95% CI , 0.40-0.87; P=0.007). Benefits for outcome seemed similar among patients receiving low- or high-dose ß-blockers (log-rank, P=0.304). Conclusions HF i EF is a distinct HF phenotype with better clinical outcomes than other phenotypes. The use of ß-blockers may be beneficial for these patients. Clinical Trial Registration URL : https://www.clinicaltrials.gov . Unique identifier: NCT01389843.