Accumulating evidence demonstrates that hypoxia‐inducible factor (HIF‐α) hydroxylase system has a critical role in vascular remodelling. Using an endothelial‐specific prolyl hydroxylase domain protein‐2 (PHD2) knockout (PHD2ECKO) mouse model, this study investigates the regulatory role of endothelial HIF‐α hydroxylase system in the development of renal fibrosis. Knockout of PHD2 in EC up‐regulated the expression of HIF‐1α and HIF‐2α, resulting in a significant decline of renal function as evidenced by elevated levels of serum creatinine. Deletion of PHD2 increased the expression of Notch3 and transforming growth factor (TGF‐β1) in EC, thus further causing glomerular arteriolar remodelling with an increased pericyte and pericyte coverage. This was accompanied by a significant elevation of renal resistive index (RI). Moreover, knockout of PHD2 in EC up‐regulated the expression of fibroblast‐specific protein‐1 (FSP‐1) and increased interstitial fibrosis in the kidney. These alterations were strongly associated with up‐regulation of Notch3 and TGF‐β1. We concluded that the expression of PHD2 in endothelial cells plays a critical role in renal fibrosis and vascular remodelling in adult mice. Furthermore, these changes were strongly associated with up‐regulation of Notch3/TGF‐β1 signalling and excessive pericyte coverage.

Background: Apical hypertrophic cardiomyopathy (AHCM) is a relatively rare form of hypertrophic cardiomyopathy (HCM), originally described in Japan and later in the West. Limited information is available on this disease in China. Hypothesis: This study was designed to describe clinical features and prognoses of patients with AHCM in China. Methods: A retrospective study of 208 consecutive patients with AHCM examined at FuWai Hospital was performed. Clinical features, mortality, and cardiovascular morbidity were analyzed. Results: The 208 patients with AHCM represented 16.0% of all HCM patients. Among them, 64.4% were pure form and 35.6% were mixed form. Compared with the pure group, the mixed group had a significantly larger left atrial diameter and thicker apical thickness. One hundred ninety-nine patients had a mean follow-up of 8.0 ± 3.5 years, cardiovascular mortality was 1.0%, and annual cardiovascular mortality was 0.1%. The 2 cardiovascular deaths were both mixed form. The probability of survival was 97.0 ± 2% at 10 years. Of the patients, 17.8% had 1 or more cardiovascular events. The probability of survival without morbid events at 10 years was 77 ± 4%. Three independent predictors of cardiovascular morbidity were identified: age at diagnosis ≥60 years, left atrial diameter ≥36 mm, and New York Heart Association class ≥III at baseline. Conclusions:The prevalence of AHCM is relatively high, and it has a benign prognosis in China. However, 17.8% of patients may develop cardiovascular events. It is important to distinguish the 2 phenotypes of AHCM; the mixed form is less common but more serious than the pure form.

Rationale Vascular maturation plays an important role in wound repair post-myocardial infarction (MI). The Notch3 is critical for pericyte recruitment and vascular maturation during embryonic development. Objective This study is to test whether Notch3 deficiency impairs vascular maturation and blunts cardiac functional recovery post-MI. Approach and results Wild type (WT) and Notch3 knockout (Notch3KO) mice were subjected to MI by the ligation of left anterior descending coronary artery (LAD). Cardiac function and coronary blood flow reserve (CFR) were measured by echocardiography. The expression of angiogenic growth factor, pericyte/capillary coverage and arteriolar formation were analyzed. Loss of Notch3 in mice resulted in a significant reduction of pericytes and small arterioles. Notch3 KO mice had impaired pericyte/capillary coverage and CFR compared to WT mice. Notch3 KO mice were more prone to ischemic injury with larger infarcted size and higher rates of mortality. The expression of CXCR-4 and VEGF/Ang-1 was significantly decreased in Notch3 KO mice. Notch3 KO mice also had few NG2+/Sca1+ and NG2+/c-kit+ progenitor cells in the ischemic area and exhibited worse cardiac function recovery at 2 weeks after MI. These were accompanied by a significant reduction of pericyte/capillary coverage and arteriolar maturation. Furthermore, Notch3 KO mice subjected to MI had increased intracellular adhesion molecule-2 (ICAM-2) expression and CD11b+ macrophage infiltration into ischemic areas compared to that of WT mice. Conclusion Notch3 mutation impairs recovery of cardiac function post-MI by the mechanisms involving the preexisting coronary microvascular dysfunction conditions, and impairment of pericyte/progenitor cell recruitment and microvascular maturation.