Novel mediators of aneurysm progression in bicuspid aortic valve disease.

Bicuspid aortic valve (BAV) disease is a congenital abnormality that is associated with ascending aortic aneurysm yet many of the molecular mechanisms remain unknown. To identify novel molecular mechanisms of aneurysm formation we completed microarray analysis of the proximal (severely dilated) and distal (less dilated) regions of the ascending aorta from five patients with BAV. We identified 180 differentially expressed genes, 40 of which were validated by RT-qPCR.

Increases in Serum Autoantibodies After Left Ventricular Assist Device Implantation.

Background: Left ventricular assist devices (LVADs) can serve as a bridge to transplant or destination therapy for patients with advanced heart failure. Implantation of LVADs is known to be associated with increases in anti-HLA antibodies, but less is known about how autoantibody levels change with the use of these devices.

Methods And Results: Autoantibody levels were quantified with the use of customized antigen microarrays in 22 patients both before and after LVAD.

Recipient hypertonic saline infusion prevents cardiac allograft dysfunction.

Objective: Hypertonic saline (HTS) has potent immune and vascular effects. We assessed recipient pretreatment with HTS on allograft function in a porcine model of heart transplantation and hypothesized that HTS infusion would limit endothelial and left ventricular (LV) dysfunction following transplantation.

Methods: Heart transplants were performed after 6 hours of cold ischemic storage.

Effects of everolimus and HLA-G on cellular proliferation and neutrophil adhesion in an in vitro model of cardiac allograft vasculopathy.

Human leukocyte antigen-G (HLA-G) expression is modulated by immunosuppressant use and is associated with lower incidence of graft rejection and cardiac allograft vasculopathy (CAV). We examined whether everolimus induces HLA-G expression and inhibits human coronary artery smooth muscle cell (HCASMC) proliferation, a critical event in CAV. Also, we examined whether TNFα-stimulated neutrophil adhesion is inhibited by HLA-G on human coronary artery endothelial cells (HCAECs).

10-Year Experience with HLA-G in Heart Transplantation.

The Human Leukocyte Antigen-G (HLA-G) is a MHC-class Ib molecule with robust immunomodulatory properties; in transplant, it inhibits cytotoxic activity of immune cells and thus has a pivotal role in protecting the allograft from immune attack. The present review details a 10-year experience investigating the influence of HLA-G on heart transplantation, allograft rejection and cardiac allograft vasculopathy development. Exploration of HLA-G in transplantation began with the initial findings of its increased expression in allograft hearts.

Progressive Aortic Dilation Is Regulated by miR-17-Associated miRNAs.

Background: Patients with a bicuspid aortic valve (BAV) are at increased risk for progressive aortic dilation associated with extracellular matrix (ECM) degradation by matrix metalloproteinases (MMP). However, the mechanisms responsible for initiating this process are unknown. In the heart, MMP activity is regulated by micro-ribonucleic acid-17 (miR-17)-related downregulation of tissue inhibitors of metalloproteinases (TIMP); a similar process may exist in the aorta.

Generation of Antigen Microarrays to Screen for Autoantibodies in Heart Failure and Heart Transplantation.

Autoantibodies directed against endogenous proteins including contractile proteins and endothelial antigens are frequently detected in patients with heart failure and after heart transplantation. There is evidence that these autoantibodies contribute to cardiac dysfunction and correlate with clinical outcomes. Currently, autoantibodies are detected in patient sera using individual ELISA assays (one for each antigen).

New Developments in HLA-G in Cardiac Transplantation.

Human Leukocyte Antigen-G (HLA-G) is a non-classical class 1b protein, whose gene is located on chromosome 6 (6p21.31). HLA-G inhibits the immune cells' cytotoxic activity by interacting with specific receptors on their membranes.

Increased cyclic guanosine monophosphate levels and continuous-flow left-ventricular assist devices: Implications for gastrointestinal bleeding.

Objectives: We examine the hypothesis that cyclic guanosine monophosphate (cGMP) levels are elevated in recipients of continuous-flow left ventricular assist devices (CF-LVADs) and that elevated cGMP levels are associated with a risk of gastrointestinal (GI) bleeding events.

Methods: The levels of cGMP, nitric oxide, platelet activation markers, platelet-derived growth factors (PDGF) AB/BB and AA, and the inflammatory mediator C-reactive protein (CRP) were examined in 19 CF-LVAD recipients, 21 patients who had heart failure, and 19 healthy control-group participants.

Results: The median level of cGMP was significantly higher in CF-LVAD recipients, compared with healthy participants (6.

The effect of insulin to decrease neointimal growth after arterial injury is endothelial nitric oxide synthase-dependent.

In vitro, insulin has mitogenic effects on vascular smooth muscle cells (VSMC) but also has protective effects on endothelial cells by stimulating nitric oxide (NO) production and endothelial nitric oxide synthase (eNOS) expression. Furthermore, NOS inhibition attenuates the effect of insulin to inhibit VSMC migration in vitro. Using an in vivo model, we have previously shown that insulin decreases neointimal growth and cell migration and increases re-endothelialization after arterial injury in normal rats.

Longitudinal assessment of inflammation in recipients of continuous-flow left ventricular assist devices.

Background: The long-term effects of continuous-flow left ventricular assist device (CF-LVAD) support on trends of inflammatory markers over time are unknown. We examined the hypothesis that the levels of inflammatory markers in CF-LVAD recipients are higher than in healthy controls and that these levels increase over time with long-term CF-LVAD support.

Methods: We examined the levels of inflammatory markers longitudinally at baseline before CF-LVAD implantation and at 3, 6, and 9 months after implantation.

Markers of inflammation in recipients of continuous-flow left ventricular assist devices.

Although the newer continuous-flow left ventricular assist devices (CF-LVADs) provide clinical advantages over the pulsatile pumps, the effects of low pulsatility on inflammation are incompletely understood. The objective of our study was to examine the levels of inflammatory mediators in CF-LVAD recipients compared with both healthy control subjects and heart failure patients who were candidates for CF-LVAD support. Plasma levels of chemokines, cytokines, and inflammatory markers were measured in 18 CF-LVAD recipients and compared with those of 14 healthy control subjects and 14 heart failure patients who were candidates for CF-LVADs.

Epidermal growth factor-like domain 7 is a novel inhibitor of neutrophil adhesion to coronary artery endothelial cells injured by calcineurin inhibition.

Background: We investigated the effect of epidermal growth factor-like domain 7 (Egfl7) on nuclear factor-κB activation, intercellular adhesion molecule-1 expression, and neutrophil adhesion to human coronary artery endothelial cells after calcineurin-inhibition-induced injury.

Methods And Results: Human coronary endothelial cells were incubated with cyclosporine (CyA) 10 μg/mL with or without Egfl7 (100 ng/mL) or the Notch receptor activator Jagged1 (200 ng/mL) for 6 to 48 hours. CyA upregulated nuclear factor-κB (p65) activity (128 ± 2% of control, P<0.

Human leukocyte antigen-G is upregulated in heart failure patients: a potential novel biomarker.

Immune activation and inflammation play critical roles in the development of heart failure (HF). Human leukocyte antigen-G (HLA-G) is a nonclassical, major histocompatibility complex class I (MHC-I) protein, upregulated in the context of transplantation, malignancy, and inflammation, and has been correlated with various clinical outcomes. We sought to evaluate the utility of plasma HLA-G in identifying patients with HF.

Tacrolimus preserves vasomotor function and maintains vascular homeostasis.

Background: Post-transplant immunosuppression is associated with endothelial dysfunction that may lead to vasculopathy. We have previously demonstrated that cyclosporine causes vascular dysfunction. In this we study examined the effect of tacrolimus (Tac) in an identical model.

Endothelin-1 antagonism and nitric oxide augmentation prevents cyclosporine-induced vasomotor impairment.

Background: We previously demonstrated that cyclosporine (CyA) impairs endothelial function as a result of alterations in nitric oxide (NO) and endothelin-1 (ET-1) regulation. Bosentan (BOS), an ET-1 antagonist, and tetrahydrobiopterin (BH₄), an eNOS cofactor, may reduce endothelial dysfunction by improving ET-1/NO homeostasis.

Methods: Lewis rats received intraperitoneal injections of CyA with BOS or with BOS+BH₄ daily for 2 weeks.

Epidermal growth factor-like domain 7 suppresses intercellular adhesion molecule 1 expression in response to hypoxia/reoxygenation injury in human coronary artery endothelial cells.

Background: Epidermal growth factor-like domain 7 (Egfl7) is a chemoattractant for endothelial cells, and its expression is restricted to endothelial cells. Hypoxia/reoxygenation (H/R) induced endothelial injury that occurs during transplantation contributes to the subsequent development of allograft vasculopathy. We investigated the effect of Egfl7 on endothelial cell intercellular adhesion molecule 1 expression in response to H/R injury.

Correlation between circulating endothelial progenitor cell function and allograft rejection in heart transplant patients.

Endothelial progenitor cells (EPCs) may contribute to rejection and cardiac allograft vasculopathy (CAV) by being intrinsically involved in the rejection process and causing neointimal hyperplasia. The mammalian target of rapamycin inhibitors (mTORi), sirolimus and everolimus, have been demonstrated to attenuate the progression of CAV and are cytotoxic to EPC. Thus, one mechanism by which mTORi may protect against CAV is by altering EPC function.

Donor pretreatment with hypertonic saline attenuates primary allograft dysfunction: a pilot study in a porcine model.

Background: Hypertonic saline (HTS) has been previously demonstrated to have immune modulatory and vascular protective effects. We assessed the effect of donor pretreatment with HTS on allograft preservation in a porcine model of orthotopic heart transplantation.

Methods And Results: Orthotopic transplants were performed after 6 hours of cold static allograft storage.

Progesterone induces human leukocyte antigen-g expression in vascular endothelial and smooth muscle cells.

Background: Human leukocyte antigen-G (HLA-G) expression in heart transplant patients has been negatively associated with acute cellular rejection and cardiac allograft vasculopathy. We assessed HLA-G expression in vascular human endothelial and smooth muscle cell cultures to determine if future therapeutic agents can be targeted toward inducing HLA-G expression to protect against allograft rejection and vasculopathy.

Methods And Results: Human coronary artery endothelial, aortic endothelial, and coronary artery smooth muscle cell cultures were exposed to cytokines (interferon-gamma or interleukin-10), hypoxia/reoxygenation stress, immunosuppressive agents (cyclosporine, sirolimus, or tacrolimus), or progesterone.

Dual immunosuppression enhances vasomotor injury: interactive effect between endothelin-1 and nitric oxide bioavailability.

Objective: Cyclosporine A and corticosteroids are associated with many side effects, such as endothelial dysfunction and transplant vasculopathy. We examined the effects of cyclosporine A and hydrocortisone exposure on endothelial function of the rat thoracic aorta.

Methods: Lewis rats were injected with cyclosporine A, hydrocortisone, cyclosporine A + hydrocortisone, or intraperitoneal saline daily for 2 weeks.

Endothelin-1 accentuates the proatherosclerotic effects associated with C-reactive protein.

Objectives: The proinflammatory marker C-reactive protein has been demonstrated to play a role in the development of atherosclerosis. Endothelin-1 and nitric oxide homeostasis is crucial for normal vasomotor function, limiting inflammatory activation and maintaining a nonthrombogenic endothelial surface. In addition to its vasoactive properties, endothelin-1 is also an inflammatory cytokine.

Elevated endothelin-1 levels impair nitric oxide homeostasis through a PKC-dependent pathway.

Background: Endothelin-1 (ET-1) plays an important role in the maintenance of vascular tone and pathological states such as ischemia/reperfusion (I/R) injury, coronary vasospasm, and cardiac allograft vasculopathy. We assessed the effects of elevated ET-1 levels as seen after I/R to determine if ET-1 modulates nitric oxide (NO) production via the translocation of specific protein kinase C (PKC) isoforms.

Methods And Results: Human saphenous vein endothelial cells (HSVECs) (n=8) were incubated with ET-1 or phosphate-buffered saline (PBS) for 24 hours.

Role of endothelin-1 and nitric oxide bioavailability in transplant-related vascular injury: comparative effects of rapamycin and cyclosporine.

Background: Cyclosporine (CyA) is associated with many side effects, including endothelial dysfunction and transplant vasculopathy (TxV). We previously demonstrated that CyA results in impairment of nitric oxide bioavailability and enhanced sensitivity to endothelin-1 (ET-1). In this study, we evaluated rapamycin (SRL) for its effects on the endothelium.