Jonathan Paul

Granulocyte Colony-Stimulating Factor Mobilizes Functional Endothelial Progenitor Cells in Patients With Coronary Artery Disease

Objective— Endothelial progenitor cells (EPCs) that may repair vascular injury are reduced in patients with coronary artery disease (CAD). We reasoned that EPC number and function may be increased by granulocyte colony-stimulating factor (G-CSF) used to mobilize hematopoietic progenitor cells in healthy donors. Methods and Results— Sixteen CAD patients had reduced CD34+/CD133+ (0.0224±0.0063% versus 0.121±0.038% mononuclear cells [MNCs], P<0.01) and CD133+/VEGFR-2+ cells, consistent with EPC phenotype (0.00033±0.00015% versus 0.0017±0.0006% MNCs, P<0.01), compared with 7 healthy controls. Patients also had fewer clusters of cells in culture, with out-growth consistent with mature endothelial phenotype (2±1/well) compared with 16 healthy subjects at high risk (13±4/well, P<0.05) or 14 at low risk (22±3/well, P<0.001) for CAD. G-CSF 10 &mgr;g/kg per day for 5 days increased CD34+/CD133+ cells from 0.5±0.2/&mgr;L to 59.5±10.6/&mgr;L and CD133+/ VEGFR-2+ cells from 0.007±0.004/&mgr;L to 1.9±0.6/&mgr;L (both P<0.001). Also increased were CD133+ cells that coexpressed the homing receptor CXCR4 (30.4±8.3/&mgr;L, P<0.05). Endothelial cell-forming clusters in 10 patients increased to 27±9/well after treatment (P<0.05), with a decline to 9±4/well at 2 weeks (P=0.06). Conclusions— Despite reduced EPCs compared with healthy controls, patients with CAD respond to G-CSF with increases in EPC number and homing receptor expression in the circulation and endothelial out-growth in culture.

Lung 18F-Fluorodeoxyglucose Positron Emission Tomography for Diagnosis and Monitoring of Pulmonary Arterial Hypertension

RATIONALE Pulmonary arterial hypertension (PAH) is a proliferative arteriopathy associated with glucose transporter-1 (Glut1) up-regulation and a glycolytic shift in lung metabolism. Glycolytic metabolism can be detected with the positron emission tomography (PET) tracer (18)F-fluorodeoxyglucose (FDG). OBJECTIVES The precise cell type in which glycolytic abnormalities occur in PAH is unknown. Moreover, whether FDG-PET is sufficiently sensitive to monitor PAH progression and detect therapeutic regression is untested. We hypothesized that increased lung FDG-PET reflects enhanced glycolysis in vascular cells and is reversible in response to effective therapies. METHODS PAH was induced in Sprague-Dawley rats by monocrotaline or chronic hypoxia (10% oxygen) in combination with Sugen 5416. Monocrotaline rats were treated with oral dichloroacetate or daily imatinib injections. FDG-PET scans and pulmonary artery acceleration times were obtained weekly. The origin of the PET signal was assessed by laser capture microdissection of airway versus vascular tissue. Metabolism was measured in pulmonary artery smooth muscle cell (PASMC) cultures, using a Seahorse extracellular flux analyzer. MEASUREMENTS AND MAIN RESULTS Lung FDG increases 1-2 weeks after monocrotaline (when PAH is mild) and is normalized by dichloroacetate and imatinib, which both also regress medial hypertrophy. Glut1 mRNA is up-regulated in both endothelium and PASMCs, but not airway cells or macrophages. PASMCs from monocrotaline rats are hyperproliferative and display normoxic activation of hypoxia-inducible factor-1α (HIF-1α), which underlies their glycolytic phenotype. CONCLUSIONS HIF-1α-mediated Glut1 up-regulation in proliferating vascular cells in PAH accounts for increased lung FDG-PET uptake. FDG-PET is sensitive to mild PAH and can monitor therapeutic changes in the vasculature.

A Central Role for CD68(+) Macrophages in Hepatopulmonary Syndrome: Reversal by Macrophage Depletion

RATIONALE The etiology of hepatopulmonary syndrome (HPS), a common complication of cirrhosis, is unknown. Inflammation and macrophage accumulation occur in HPS; however, their importance is unclear. Common bile duct ligation (CBDL) creates an accepted model of HPS, allowing us to investigate the cause of HPS. OBJECTIVES We hypothesized that macrophages are central to HPS and investigated the therapeutic potential of macrophage depletion. METHODS Hemodynamics, alveolar-arterial gradient, vascular reactivity, and histology were assessed in CBDL versus sham rats (n = 21 per group). The effects of plasma on smooth muscle cell proliferation and endothelial tube formation were measured. Macrophage depletion was used to prevent (gadolinium) or regress (clodronate) HPS. CD68(+) macrophages and capillary density were measured in the lungs of patients with cirrhosis versus control patients (n = 10 per group). MEASUREMENTS AND MAIN RESULTS CBDL increased cardiac output and alveolar-arterial gradient by causing capillary dilatation and arteriovenous malformations. Activated CD68(+)macrophages (nuclear factor-κB+) accumulated in HPS pulmonary arteries, drawn by elevated levels of plasma endotoxin and lung monocyte chemoattractant protein-1. These macrophages expressed inducible nitric oxide synthase, vascular endothelial growth factor, and platelet-derived growth factor. HPS plasma increased endothelial tube formation and pulmonary artery smooth muscle cell proliferation. Macrophage depletion prevented and reversed the histological and hemodynamic features of HPS. CBDL lungs demonstrated increased medial thickness and obstruction of small pulmonary arteries. Nitric oxide synthase inhibition unmasked exaggerated pulmonary vasoconstrictor responses in HPS. Patients with cirrhosis had increased pulmonary intravascular macrophage accumulation and capillary density. CONCLUSIONS HPS results from intravascular accumulation of CD68(+)macrophages. An occult proliferative vasculopathy may explain the occasional transition to portopulmonary hypertension. Macrophage depletion may have therapeutic potential in HPS.

GRK2-Mediated Inhibition of Adrenergic and Dopaminergic Signaling in Right Ventricular Hypertrophy Therapeutic Implications in Pulmonary Hypertension

Background—The cause and consequences of impaired adrenergic signaling in right ventricular failure/hypertrophy (RVH) are poorly understood. We hypothesized that G protein–coupled receptor kinase-2 (GRK2)–mediated uncoupling of &bgr;-adrenergic receptor signaling impairs inotropic reserve. The implications of right ventricular (RV) adrenergic remodeling for inotrope selection and the therapeutic benefit of interrupting G&bgr;&ggr;–GRK2 interaction, using gallein, were tested. Methods and Results—Chamber-specificity and cellular localization of adrenergic remodeling were compared in rodent RVH associated with pulmonary arterial hypertension (PAH-RVH; SU5416+chronic-hypoxia or Monocrotaline) versus pulmonary artery banding–induced RVH (PAB-RVH). Results were corroborated in RV arrays from 10 PAH patients versus controls. Inotropic reserve was assessed in RV- and left ventricular–Langendorff models and in vivo. Gallein therapy (1.8 mg/kg/day ×2-weeks) was assessed. Despite similar RVH, cardiac output (58.3±4.9 versus 82.9±4.8 mL/min; P<0.001) and treadmill distance (41.5±11.6 versus 244.1±12.4 m; P<0.001) were lower in PAH-RVH versus PAB-RVH. In PAH-RVH versus PAB-RVH there was greater downregulation of &bgr;1-, &agr;1- and dopamine-1 receptors, more left ventricular involvement, and greater impairment of RV contractile reserve. RV GRK2 activity increased in parallel with a reduction in both adrenergic receptor expression and inotrope-stimulated cAMP levels (P<0.01). &bgr;1-receptor downregulation also occurred in human PAH-RVH. Dobutamine was superior to dopamine as an RV inotrope, both ex vivo and in vivo. Conclusions—GRK2-mediated desensitization-downregulation of adrenergic and dopaminergic receptors impairs inotropic reserve in PAH-RVH. Acute inotropic support in RVH is best accomplished by dobutamine, reflecting its better coupling to adenylyl cyclase and the reliance of dopamine on dopamine-1–receptor signaling, which is impaired in RVH. Inhibiting G&bgr;&ggr;–GRK2 interactions has therapeutic benefit in RVH.

Endothelial progenitor cell mobilization and increased intravascular nitric oxide in patients undergoing cardiac rehabilitation.

PURPOSE: We investigated whether cardiac rehabilitation participation increases circulating endothelial progenitor cells (EPCs) and benefits vasculature in patients already on stable therapy previously shown to augment EPCs and improve endothelial function. METHODS: Forty-six of 50 patients with coronary artery disease completed a 36-session cardiac rehabilitation program: 45 were treated with HMG-CoA reductase inhibitor (statin) therapy ≥1 month (average baseline low-density lipoprotein cholesterol = 81 mg/dL). Mononuclear cells isolated from blood were quantified for EPCs by flow cytometry (CD133+/VEGFR-2+ cells) and assayed in culture for EPC colony-forming units (CFUs). In 23 patients, EPCs were stained for annexin-V as a marker of apoptosis, and nitrite was measured in blood as an indicator of intravascular nitric oxide. RESULTS: Endothelial progenitor cells increased from 35 ± 5 to 63 ± 10 cells/mL, and EPC-CFUs increased from 0.9 ± 0.2 to 3.1 ± 0.6 per well (both P < .01), but 11 patients had no increase in either measure. Those patients whose EPCs increased from baseline showed significant increases in nitrite and reduction in annexin-V staining (both P < .01) versus no change in patients without increase in EPCs. Over the course of the program, EPCs increased prior to increase in nitrite in the blood. CONCLUSIONS: Cardiac rehabilitation in patients receiving stable statin therapy and with low-density lipoprotein cholesterol at goal increases EPC number, EPC survival, and endothelial differentiation potential, associated with increased nitric oxide in the blood. Although this response was observed in most patients, a significant minority showed neither EPC mobilization nor increased nitric oxide in the blood.

Percutaneous Transcatheter Aortic Valve Closure Successfully Treats Left Ventricular Assist Device–Associated Aortic Insufficiency and Improves Cardiac Hemodynamics

OBJECTIVES This study sought to assess the effectiveness of a novel percutaneous method to treat left ventricular assist device (LVAD)-associated severe aortic insufficiency (AI) in a series of patients determined to be poor reoperative candidates. BACKGROUND The increased use of continuous-flow LVAD in advanced heart failure has led to marked changes in the management of patients with this condition. However, secondary AI can become a significant complication. METHODS Five patients with continuous-flow LVAD and severe post-LVAD AI underwent percutaneous transcatheter aortic valve closure from September to October 2011 at a single quaternary care academic medical center. All patients had LVAD implanted as destination therapy. LVAD parameters, hemodynamics, and echocardiographic measurements were obtained before and after aortic valve closure. RESULTS All patients underwent successful closure with the Amplatzer cribriform device (AGA Medical, Plymouth, Minnesota) via a percutaneous transcatheter femoral approach with a significant reduction of AI from severe to trivial. Cardiac hemodynamics improved, and the pulmonary capillary wedge pressure was reduced in all patients. There was no change in mitral or tricuspid regurgitation, LVAD power, or pulsatility index. CONCLUSIONS Percutaneous transcatheter closure of the aortic valve effectively treats LVAD-associated AI and reduces pulmonary capillary wedge pressure. This procedure should be considered to treat LVAD-associated AI in patients who are poor candidates for repeat operation. Further data are needed to assess long-term results.

TCT-379 Percutaneous Transcatheter Aortic Valve Closure Successfully Treats Left Ventricular Assist Device-Associated Aortic Insufficiency and Improves Cardiac Hemodynamics

The increased use of continuous-flow LVADs in advanced heart failure has led to marked changes in the management of patients with this condition. However, secondary AI can become a significant complication. Our objective was to assess the effectiveness of a novel percutaneous method to treat left

Percutaneous Transcatheter Closure of the Aortic Valve to Treat Cardiogenic Shock in a Left Ventricular Assist Device Patient With Severe Aortic Insufficiency

In this case report, we present a patient status post left ventricular assist device implantation complicated by de novo aortic insufficiency. At 8 months postimplant, the patient underwent a reoperative aortic valve repair, without complete closure of the valve. Three months after reoperation, the patient developed cardiogenic shock secondary to recurrent, severe aortic insufficiency. Ultimately, the patient underwent percutaneous, transcatheter closure of the aortic valve with an Amplatzer Cribiform device (AGA Medical Corp, Plymouth, MN). Two months post procedure, the patient remains stable with improved symptoms and functional status, and without evidence of further aortic insufficiency or device migration.

Percutaneous Transcatheter Closure of the Native Aortic Valve to Treat De Novo Aortic Insufficiency After Implantation of a Left Ventricular Assist Device

A 54-year-old female with a HeartMate II (Thoratec, Pleasanton, California) left ventricular assist device (LVAD) presented 3 months after implantation with new-onset severe aortic insufficiency (AI) and cardiogenic shock. A reoperation for surgical aortic valve closure was too high risk, so the

Mechanical chest compressions improve rate of return of spontaneous circulation and allow for initiation of percutaneous circulatory support during cardiac arrest in the cardiac catheterization laboratory

BACKGROUND Performing advanced cardiac life support (ACLS) in the cardiac catheterization laboratory (CCL) is challenging. Mechanical chest compression (MCC) devices deliver compressions in a small space, allowing for simultaneous percutaneous coronary intervention and reduced radiation exposure to rescuers. In refractory cases, MCC devices allow rescuers to initiate percutaneous mechanical circulatory support (MCS) and extracorporeal life support (ECLS) during resuscitation. This study sought to assess the efficacy and safety of MCC when compared to manual compressions in the CCL. METHODS We performed a retrospective analysis of patients who received ACLS in the CCL at our institution between May 2011 and February 2016. Baseline characteristics, resuscitation details, and outcomes were compared between patients who received manual and mechanical compressions. RESULTS Forty-three patients (67% male, mean age 58 years) required chest compressions for cardiac arrest while in the CCL (12 manual and 31 MCC). Patients receiving MCC were more likely to achieve return of spontaneous circulation (ROSC) (74% vs. 42%, p=0.05). Of those receiving MCC, twenty-two patients (71%) were treated with MCS. Patients receiving percutaneous ECLS were more likely to achieve ROSC (100% vs. 53%, p=0.003) and suffered no episodes of limb loss or TIMI major bleeding. There were no significant differences in 30-day survival or survival to hospital discharge between groups. CONCLUSIONS Use of MCC during resuscitation of cardiac arrest in the CCL increases the rate of ROSC. Simultaneous implantation of MCS, including percutaneous ECLS, is feasible and safe during MCC-assisted resuscitation in the CCL.