High density lipoprotein from patients with valvular heart disease uncouples endothelial nitric oxide synthase.

Normal high density lipoprotein (HDL) protects vascular function; however these protective effects of HDL may absent in valvular heart disease (VHD). Because vascular function plays an important role in maintaining the circulation post-cardiac surgery and some patients are difficult to stabilize, we hypothesized that a deleterious vascular effect of HDL may contribute to vascular dysfunction in VHD patients following surgery. HDL was isolated from age-match 28 healthy subjects and 84 patients with VHD and during cardiac surgery. HDL pro-inflammation index was measured and the effects of HDL on vasodilation, protein interaction, generation of nitric oxide (NO) and superoxide were determined. Patients with VHD received either simvastatin (20mg/d) or routine medications, and endothelial effects of HDL were characterized. HDL inflammation index significantly increased in VHD patients and post-cardiac surgery. HDL from VHD patients and post-cardiac surgery significantly impaired endothelium-dependent vasodilation, inhibited both Akt and endothelial nitric oxide synthase (eNOS) phosphorylation at S1177, eNOS associated with heat shock protein 90 (HSP90), NO production and increased eNOS phosphorylation at T495 and superoxide generation. Simvastatin therapy partially reduced HDL inflammation index, improved the capacity of HDL to stimulate eNOS and Akt phosphorylation at S1177, eNOS associated with HSP90, NO production, reduced eNOS phosphorylation at T495 and superoxide generation, and improved endothelium-dependent vasodilation. Our data demonstrated that HDL from VHD patients and cardiac surgery contributed to endothelial dysfunction through uncoupling of eNOS. This deleterious effect can be reversed by simvastatin, which improves the vasoprotective effects of HDL. Targeting HDL may be a therapeutic strategy for maintaining vascular function and improving the outcomes post-cardiac surgery.

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

Mitral valve endothelial cells are important for maintaining lifelong mitral valve integrity and function. Plasma endothelial microparticles (EMPs) increased in various pathological conditions related to activation of endothelial cells. However, whether EMPs will increase in mitral valve disease and their relationship remains unclear. Here, 81 patients with mitral valve disease and 45 healthy subjects were analyzed for the generation of EMPs by flow cytometry. Human mitral valve endothelial cells (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 (O(2)(∙-)) 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 O(2)(∙-) 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.

A simple modification results in greater success in the model of coronary artery ligation and myocardial ischemia in mice.

Mouse models of myocardial ischemic preconditioning (IPC) and ischemic postconditioning (IPD) have proven to be very useful models of cardiovascular diseases. In 2010, Gao described a novel procedure without the aid of mechanical ventilation. However, the technique of heart externalization could not be applied to mouse models of IPC or IPD due to the limited time frame of the technique. We proposed a modified simple and safe method using lung recruitment and short-term ventilation to perform the procedure in mice with IPC or IPD. The mice were randomly divided into 4 groups: the modified groups, M-IPC and M-IPD, and the conventional groups, C-IPC and C-IPD. In the 2 modified groups, the mice were removed from the ventilator and allowed to resume breathing spontaneously upon completion of the lung recruitment and the rapid closure of the thorax. Our study demonstrated that the postoperative recovery time was significantly reduced for the modified groups compared with the 2 conventional groups. Moreover, the inflammatory damages were attenuated by the modified method compared with the conventional method. In addition, the modified method significantly increased the survival rates of mice with IPC or IPD. The modified method improved the survival rates of mouse models of myocardial ischemia.

Angiogenic and Antiangiogenic mechanisms of high density lipoprotein from healthy subjects and coronary artery diseases patients.

Normal high-density lipoprotein (nHDL) in normal, healthy subjects is able to promote angiogenesis, but the mechanism remains incompletely understood. HDL from patients with coronary artery disease may undergo a variety of oxidative modifications, rendering it dysfunctional; whether the angiogenic effect is mitigated by such dysfunctional HDL (dHDL) is unknown. We hypothesized that dHDL compromises angiogenesis. The angiogenic effects of nHDL and dHDL were assessed using endothelial cell culture, endothelial sprouts from cardiac tissue from C57BL/6 mice, zebrafish model for vascular growth and a model of impaired vascular growth in hypercholesterolemic low-density lipoprotein receptor null(LDLr-/-)mice. MiRNA microarray and proteomic analyses were used to determine the mechanisms. Lipid hydroperoxides were greater in dHDL than in nHDL. While nHDL stimulated angiogenesis, dHDL attenuated these responses. Protein and miRNA profiles in endothelial cells differed between nHDL and dHDL treatments. Moreover, nHDL suppressed miR-24-3p expression to increase vinculin expression resulting in nitric oxide (NO) production, whereas dHDL delivered miR-24-3p to inhibit vinculin expression leading to superoxide anion (O2•-) generation via scavenger receptor class B type 1. Vinculin was required for endothelial nitric oxide synthase (eNOS) expression and activation and modulated the PI3K/AKT/eNOS and ERK1/2 signaling pathways to regulate nHDL- and VEGF-induced angiogenesis. Vinculin overexpression or miR-24-3p inhibition reversed dHDL-impaired angiogenesis. The expressions of vinculin and eNOS and angiogenesis were decreased, but the expression of miR-24-3p and lipid hydroperoxides in HDL were increased in the ischemic lower limbs of hypercholesterolemic LDLr-/- mice. Overexpression of vinculin or miR-24-3p antagomir restored the impaired-angiogenesis in ischemic hypercholesterolemic LDLr-/- mice. Collectively, nHDL stimulated vinculin and eNOS expression to increase NO production by suppressing miR-24-3p to induce angiogenesis, whereas dHDL inhibited vinculin and eNOS expression to enhance O2•- generation by delivering miR-24-3p to impair angiogenesis, and that vinculin and miR-24-3p may be therapeutic targets for dHDL-impaired angiogenesis.

Mitral valve replacement via minimally invasive totally thoracoscopic surgery versus traditional median sternotomy: a propensity score matched comparative study.

BACKGROUND: To compare surgical outcomes after mitral valve replacement via either minimally invasive thoracoscopic (MIs) or traditional median sternotomy (MS) surgery and determine the short- and mid-term clinical outcomes of the MI approach. METHODS: All patients who received either MIs (n=405) or MS (n=691) mitral valve replacement surgery at the Guangdong Cardiovascular Institute between January 2012 and July 2015 were analyzed for outcome differences due to surgical approach using propensity score matching. The best 202 matches from the MI group and the MS group were analyzed. The clinical data of the two groups were collected, including preoperative cardiac function, operative data, postoperative complications, and follow-up. RESULTS: A final total of 404 patients were included in this study after propensity score matching; the MIs group and the MS group each contained 202 patients. The two groups were similar in age, weight, pathological changes, and surgical approach. Compared with the MS group, the MIs group had a longer cardiopulmonary bypass time (P<0.001), aortic cross-clamping time (P<0.001), and total procedure time (P<0.001). There were no significant differences between the groups regarding in-hospital mortality, stroke, pneumonia, acute renal failure, arrhythmia, and chylothorax. The MS group had significantly more patients with poor wound healing than the MIs group (P=0.004). The MI group had a lower rate of transfusion (P=0.037), shorter ventilation time (P=0.041), shorter ICU stay (P=0.033), reduced chest tube drainage and length of chest tube stay (P<0.001), and shorter hospital stay (P<0.001). There was no significant difference between the groups in hospital re-admission for bleeding, but the total hospitalization cost was higher in the MIs group (P=0.002). The mean follow-up was 26.59±12.33 months, the 1-year postoperative survival rate was 98.86%, and the overall survival rate was 97.44%. Compared with the MS group, the MIs group recovered earlier (P<0.05), and returned to work or study earlier (P<0.05). More patients in the MIs group were satisfied with the wound (P<0.001). The MS group had a higher incidence of postoperative osteomyelitis than the MIs group (P=0.028). There were no significant differences between groups in rates of mortality, stroke, pacemaker, reoperation, or 36-item Short Form Health Survey score. CONCLUSIONS: Compared with the MS approach, the MIs method of mitral valve replacement has longer cardiopulmonary bypass time and aortic cross-clamp time; however, it does not increase the risk of mortality and complications. Furthermore, MIs causes less trauma, fewer transfusions, less wound infection, faster recovery, faster return to work or study, and greater satisfaction with the incision in the mid-term. MI cardiac surgery is safe, effective, and feasible.

MicroRNA-34a targets regulator of calcineurin 1 to modulate endothelial inflammation after fetal cardiac bypass in goat placenta.

INTRODUCTION: Placental dysfunction characterized by vascular endothelial inflammation is one of the most notable responses to fetal cardiac bypass. Regulator of calcineurin 1 (RCAN1) is an important regulator of inflammatory responses. MicroRNAs (miRNAs) are essential post-transcriptional modulators of gene expression, and miRNA-34a (miR-34a) was showed to activate vascular endothelial inflammation. We hypothesized that miR-34a may be a key regulator of placental dysfunction after fetal cardiac bypass. METHODS: We evaluated miRNA expression in goat placentas via small RNA sequencing, quantitative real-time polymerase chain reaction (qRT-PCR) and in situ hybridization. Expression of miRNA target genes was determined via bioinformatics analyses and dual luciferase reporter assays. Furthermore, human umbilical vein endothelial cells (HUVECs) were transfected with miR-34a or a control sequence. The RCAN1, nuclear factor of activated T-cells (NFATC1) and nuclear factor kappa-B (NF-κB) levels in HUVECs and placentas were evaluated via Western blot and qRT-PCR. RESULTS: We demonstrated that miR-34a was highly enriched in goat placenta after cardiopulmonary bypass. Moreover, RCAN1 was identified as a novel direct target of miR-34a. Transfection of miR-34a led to decreased RCAN1 expression and increased NFATC1 and NF-κB expression in HUVECs. Conversely, inhibition of miR-34a rescued RCAN1 expression and reduced NFATC1 and NF-κB expression in HUVECs. CONCLUSIONS: We demonstrated a remarkable role of miR-34a as a regulator of NFATC1-associated placental inflammation through direct targeting of RCAN1. MiR-34a could serve as a novel therapeutic target for limiting the progression of placental inflammation after fetal cardiac bypass.