Early Alteration of Right Ventricle-Pulmonary Artery Coupling in Experimental Heart Failure With Preserved Ejection Fraction.

BACKGROUND: Pulmonary hypertension and right ventricular (RV) dysfunction are major prognostic determinants in patients with heart failure with preserved ejection fraction (HFpEF). The underlying pathomechanisms remain unknown. In this context, we sought to study the pathogenesis of pulmonary hypertension and RV dysfunction in a rat model of obesity-associated HFpEF. METHODS AND RESULTS: HFpEF was induced in obesity-prone rats fed a high-fat diet (n=13) and compared with obesity-resistant rats fed with standard chow (n=9). After 12 months, the animals underwent echocardiographic and hemodynamic evaluation followed by tissue sampling for pathobiological assessment. HFpEF rats presented mild RV pressure overload (with increased RV systolic pressure and pulmonary vascular resistance). No changes in pulmonary artery medial thickness and ex vivo vasoreactivity (to acetylcholine and endothelin-1) were observed and RNA sequencing analysis failed to identify gene clustering in HFpEF lungs. However, released nitric oxide levels were decreased in HFpEF pulmonary artery, while lung expression of preproendothelin-1 was increased. In HFpEF rats, RV structure and function were altered, with RV enlargement, decreased RV fractional area change and free wall longitudinal fractional shortening, together with altered right ventricle-pulmonary artery coupling (estimated by tricuspid annular plane systolic excursion/systolic pulmonary artery pressure). Hypertrophy and apoptosis (evaluated by transferase biotin- dUTP nick-end labeling staining) were increased in right and left ventricles of HFpEF rats. There was an inverse correlation between tricuspid annular plane systolic excursion/systolic pulmonary artery pressure and RV apoptotic rate. Plasma levels of soluble suppression of tumorigenicity-2, interleukin-1ß, -6 and -17A were increased in HFpEF rats. CONCLUSIONS: Obesity-associated HFpEF in rats spontaneously evolves to pulmonary hypertension-HFpEF associated with impaired right ventricle-pulmonary artery coupling that appears disproportionate to a slight increase in RV afterload.

Lung diffusion capacity correlates with pre-implant pulmonary hypertension and predicts outcome after LVAD implantation.

AIMS: Diffusing capacity of the lung for carbon monoxide (DLCO ) reduction is common in heart failure (HF) and is associated with a worse prognosis. Correlations between DLCO and pulmonary hypertension (PH) are unclear, and published data are conflicting; it has been shown that DLCO impairment may persist or even worsen after normalization of pulmonary pressures following left ventricle assist device (LVAD) implantation, maybe reflecting persistent pulmonary damage. We aimed to investigate the impact of pre-implant DLCO and central haemodynamics on outcome in patients with advanced HF implanted with a LVAD. METHODS AND RESULTS: We retrospectively analysed pre-implant and post-implant data from 42 patients implanted with a LVAD at our institution. Out of 42 patients, 35 had post-capillary PH before implantation, including 17 with combined post- and pre-capillary PH (Cpc-PH). Median DLCO was 59% (IQR 47-68%), and it inversely correlated with pulmonary vascular resistance (PVR) (P 0.037) and diastolic pulmonary gradient (DPG) (P 0.042). Compared with baseline, LVAD resulted in improvement in LV diameter (LVDd, P < 0.001), mitral regurgitation (P 0.022), and PH (mPAP 24 vs. 36 mmHg, P < 0.001; PAWP 12 vs. 23 mmHg, P 0.001; pulmonary artery compliance, CPA 3.1 vs. 1.9 mL/mmHg, P 0.021). Lower DLCO and Cpc-PH at baseline were associated with a better LV reverse remodelling post-implantation (P 0.027 for LVDd) but also with a smaller gain in CPA (P 0.049). CONCLUSIONS: Before LVAD implantation, DLCO impairment is associated with higher PVR and DPG, suggesting that it might be an expression of persistent pulmonary damage occurring in Cpc-PH. After LVAD implantation, both LV dimension and haemodynamics improve. Lower pre-implant DLCO is associated with better LV reverse remodelling.

ISHLT consensus statement: Perioperative management of patients with pulmonary hypertension and right heart failure undergoing surgery.

Pulmonary hypertension (PH) is a risk factor for morbidity and mortality in patients undergoing surgery and anesthesia. This document represents the first international consensus statement for the perioperative management of patients with pulmonary hypertension and right heart failure. It includes recommendations for managing patients with PH being considered for surgery, including preoperative risk assessment, planning, intra- and postoperative monitoring and management strategies that can improve outcomes in this vulnerable population. This is a comprehensive document that includes common perioperative patient populations and surgical procedures with unique considerations.

Early-onset and severe pulmonary arterial hypertension due to a novel compound heterozygous association of rare VHL mutations: A case report and review of existing data.

Very rare cases of pulmonary arterial hypertension (PAH) have been linked to homozygous or compound heterozygous von Hippel-Lindau (VHL) tumor suppressor gene mutations, while heterozygous VHL mutations lead to VHL tumor syndrome. Although those entities are defined, the genotype-phenotype correlation is incompletely understood, and patient management recommendations are lacking. Here, we describe a case of severe early-onset PAH due to a so-far unreported compound heterozygous association of VHL mutations and review the existing data.

Endothelin-1 induces lysyl oxidase expression in pulmonary artery smooth muscle cells.

The increase in thickening of the arterial wall of pulmonary arterial hypertension (PAH) includes cellular proliferation as well as matrix deposition and interrupted internal elastic lamina (IEL) consisting of a thick homogeneous sheet of elastin. Little is, although, known about the detail of IEL formation in PAH. Endothelin-1 is overexpressed in pulmonary arterioles of PAH. We aimed to examine the expression of genes contributing to IEL formation in pulmonary artery smooth muscle cells (PASMCs) especially focused on lysyl oxidase (LOx), an exreacellular matrix enzyme that catalyzes the cross-linking of collagens or elastin. We quantified mRNA expressions of genes contributing to IEL formation including LOx in PASMCs using real-time quantitative polymerase chain reaction. We stimulated human PASMCs with endothelin-1 with prostacyclin or trapidil. Endothelin-1 significantly increased LOx expression. Prostacyclin and trapidil restored endothelin-1-induced LOx expression to the basal level. Endothelin-1 increased LOx expression strongly in PASMCs from PAH patients compared to those from controls. Trapidil reduced LOx expression only in PASMCs from PAH patients. Overexpressed endothelin-1 in PAH patients can increase expression of LOx and agitate cross-linking of elastin and collagen, resulting in ectopic deposition of these in the vascular media.

Mechanical versus humoral determinants of brain death-induced lung injury.

BACKGROUND: The mechanisms of brain death (BD)-induced lung injury remain incompletely understood, as uncertainties persist about time-course and relative importance of mechanical and humoral perturbations. METHODS: Brain death was induced by slow intracranial blood infusion in anesthetized pigs after randomization to placebo (n = 11) or to methylprednisolone (n = 8) to inhibit the expression of pro-inflammatory mediators. Pulmonary artery pressure (PAP), wedged PAP (PAWP), pulmonary vascular resistance (PVR) and effective pulmonary capillary pressure (PCP) were measured 1 and 5 hours after Cushing reflex. Lung tissue was sampled to determine gene expressions of cytokines and oxidative stress molecules, and pathologically score lung injury. RESULTS: Intracranial hypertension caused a transient increase in blood pressure followed, after brain death was diagnosed, by persistent increases in PAP, PCP and the venous component of PVR, while PAWP did not change. Arterial PO2/fraction of inspired O2 (PaO2/FiO2) decreased. Brain death was associated with an accumulation of neutrophils and an increased apoptotic rate in lung tissue together with increased pro-inflammatory interleukin (IL)-6/IL-10 ratio and increased heme oxygenase(HO)-1 and hypoxia inducible factor(HIF)-1 alpha expression. Blood expressions of IL-6 and IL-1ß were also increased. Methylprednisolone pre-treatment was associated with a blunting of increased PCP and PVR venous component, which returned to baseline 5 hours after BD, and partially corrected lung tissue biological perturbations. PaO2/FiO2 was inversely correlated to PCP and lung injury score. CONCLUSIONS: Brain death-induced lung injury may be best explained by an initial excessive increase in pulmonary capillary pressure with increased pulmonary venous resistance, and was associated with lung activation of inflammatory apoptotic processes which were partially prevented by methylprednisolone.

Roles of inflammation and apoptosis in experimental brain death-induced right ventricular failure.

BACKGROUND: Right ventricular (RV) dysfunction remains the leading cause of early death after cardiac transplantation. Methylprednisolone is used to improve graft quality; however, evidence for that remains empirical. We sought to determine whether methylprednisolone, acting on inflammation and apoptosis, might prevent brain death-induced RV dysfunction. METHODS: After randomization to placebo (n = 11) or to methylprednisolone (n = 8; 15 mg/kg), 19 pigs were assigned to a brain-death procedure. The animals underwent hemodynamic evaluation at 1 and 5 hours after Cushing reflex (i.e., hypertension and bradycardia). The animals euthanized, and myocardial tissue was sampled. This was repeated in a control group (n = 8). RESULTS: At 5 hours after the Cushing reflex, brain death resulted in increased pulmonary artery pressure (27 ± 2 vs 18 ± 1 mm Hg) and in a 30% decreased ratio of end-systolic to pulmonary arterial elastances (Ees/Ea). Cardiac output and right atrial pressure did not change. This was prevented by methylprednisolone. Brain death-induced RV dysfunction was associated with increased RV expression of heme oxygenase-1, interleukin (IL)-6, IL-10, IL-1ß, tumor necrosis factor (TNF)-α, IL-1 receptor-like (ST)-2, signal transducer and activator of transcription-3, intercellular adhesion molecules-1 and -2, vascular cell adhesion molecule-1, and neutrophil infiltration, whereas IL-33 expression decreased. RV apoptosis was confirmed by terminal deoxynucleotide transferase-mediated deoxy uridine triphosphate nick-end labeling staining. Methylprednisolone pre-treatment prevented RV-arterial uncoupling and decreased RV expression of TNF-α, IL-1 receptor-like-2, intercellular adhesion molecule-1, vascular cell adhesion molecule-1, and neutrophil infiltration. RV Ees/Ea was inversely correlated to RV TNF-α and IL-6 expression. CONCLUSIONS: Brain death-induced RV dysfunction is associated with RV activation of inflammation and apoptosis and is partly limited by methylprednisolone.

Myocardial Structural and Biological Anomalies Induced by High Fat Diet in Psammomys obesus Gerbils.

BACKGROUND: Psammomys obesus gerbils are particularly prone to develop diabetes and obesity after brief period of abundant food intake. A hypercaloric high fat diet has been shown to affect cardiac function. Here, we sought to determine whether a short period of high fat feeding might alter myocardial structure and expression of calcium handling proteins in this particular strain of gerbils. METHODS: Twenty Psammomys obesus gerbils were randomly assigned to receive a normal plant diet (controls) or a high fat diet. At baseline and 16-week later, body weight, plasma biochemical parameters (including lipid and carbohydrate levels) were evaluated. Myocardial samples were collected for pathobiological evaluation. RESULTS: Sixteen-week high fat dieting resulted in body weight gain and hyperlipidemia, while levels of carbohydrates remained unchanged. At myocardial level, high fat diet induced structural disorganization, including cardiomyocyte hypertrophy, lipid accumulation, interstitial and perivascular fibrosis and increased number of infiltrating neutrophils. Myocardial expressions of pro-apoptotic Bax-to-Bcl-2 ratio, pro-inflammatory cytokines [interleukin (IL)-1ß and tumor necrosis factor (TNF)-α], intercellular (ICAM1) and vascular adhesion molecules (VCAM1) increased, while gene encoding cardiac muscle protein, the alpha myosin heavy polypeptide (MYH6), was downregulated. Myocardial expressions of sarco(endo)plasmic calcium-ATPase (SERCA2) and voltage-dependent calcium channel (Cacna1c) decreased, while protein kinase A (PKA) and calcium-calmodulin-dependent protein kinase (CaMK2D) expressions increased. Myocardial expressions of ryanodine receptor, phospholamban and sodium/calcium exchanger (Slc8a1) did not change. CONCLUSIONS: We conclude that a relative short period of high fat diet in Psammomys obesus results in severe alterations of cardiac structure, activation of inflammatory and apoptotic processes, and altered expression of calcium-cycling determinants.

Heme oxygenase-1 and inflammation in experimental right ventricular failure on prolonged overcirculation-induced pulmonary hypertension.

Heme oxygenase (HO)-1 is a stress response enzyme which presents with cardiovascular protective and anti-inflammatory properties. Six-month chronic overcirculation-induced pulmonary arterial hypertension (PAH) in piglets has been previously reported as a model of right ventricular (RV) failure related to the RV activation of apoptotic and inflammatory processes. We hypothesized that altered HO-1 signalling could be involved in both pulmonary vascular and RV changes. Fifteen growing piglets were assigned to a sham operation (n = 8) or to an anastomosis of the left innominate artery to the pulmonary arterial trunk (n = 7). Six months later, hemodynamics was evaluated after closure of the shunt. After euthanasia of the animals, pulmonary and myocardial tissue was sampled for pathobiological evaluation. Prolonged shunting was associated with a tendency to decreased pulmonary gene and protein expressions of HO-1, while pulmonary gene expressions of interleukin (IL)-33, IL-19, intercellular adhesion molecule (ICAM)-1 and -2 were increased. Pulmonary expressions of constitutive HO-2 and pro-inflammatory tumor necrosis factor (TNF)-α remained unchanged. Pulmonary vascular resistance (evaluated by pressure/flow plots) was inversely correlated to pulmonary HO-1 protein and IL-19 gene expressions, and correlated to pulmonary ICAM-1 gene expression. Pulmonary arteriolar medial thickness and PVR were inversely correlated to pulmonary IL-19 expression. RV expression of HO-1 was decreased, while RV gene expressions TNF-α and ICAM-2 were increased. There was a correlation between RV ratio of end-systolic to pulmonary arterial elastances and RV HO-1 expression. These results suggest that downregulation of HO-1 is associated to PAH and RV failure.

Downregulated bone morphogenetic protein signaling in nitrofen-induced congenital diaphragmatic hernia.

PURPOSE: Bone morphogenetic proteins (BMP) have been shown to play crucial roles in not only lung and heart development, but also in the pathogenesis of pulmonary vascular remodeling in pulmonary hypertension (PH). We therefore hypothesized that BMP signaling could be altered in nitrofen-induced congenital diaphragmatic hernia (CDH) and associated PH. METHODS: Pregnant rats were exposed to either 100 mg nitrofen or vehicle on embryonic day (E) 9.5. On E17 and E21, fetuses were delivered by cesarean section, killed and checked for left-sided CDH. The tissue was then harvested for pathobiological evaluation. RESULTS: In nitrofen-induced CDH, pulmonary expressions of BMP4, BMP receptor (BMPR) type 2 and Id1 decreased on E17 and E21. On E17, pulmonary gremlin-1 expression increased, while BMP7 decreased. In the lungs, Id1 expression was correlated to BMP4 and BMPR2 and inversely correlated to gremlin-1 expression. Myocardial expressions of BMPR2, BMPR1A, BMP7 and SERCA-2A decreased, while gremlin-1 and noggin expressions increased on E17. On E21, myocardial expressions of Id1 and SERCA-2A decreased, while gremlin-1 expression increased. Moreover, BMPR2 and BMPR1A expressions were correlated to SERCA-2A expression and inversely correlated to pro-apoptotic Bax/Bcl2 ratio within the myocardium. CONCLUSION: Downregulation of BMP signaling seems to contribute to pulmonary and myocardial anomalies observed in nitrofen-induced CDH.

Prolonged overcirculation-induced pulmonary arterial hypertension as a cause of right ventricular failure.

AIMS: Three-month chronic systemic-to-pulmonary shunting in growing piglets has been reported as an early pulmonary arterial hypertension (PAH) model with preserved right ventricular (RV) function. We sought to determine whether prolonged shunting might be associated with more severe PAH and RV failure. METHODS AND RESULTS: Fourteen growing piglets were randomized to a sham operation or the anastomosis of the left innominate artery to the pulmonary arterial trunk. Six months later, the shunt was closed and the animals underwent haemodynamic evaluation followed by tissue sampling for pathobiological assessment. Prolonged shunting had resulted in increased mean pulmonary artery pressure (22 ± 2 versus 17 ± 1 mmHg) and pulmonary arteriolar medial thickness, while cardiac output was decreased. However, RV-arterial coupling was markedly deteriorated, with a ~50% decrease in the ratio of end-systolic to pulmonary arterial elastances (Ees/Ea). Lung tissue expressions of endothelin-1, angiopoietin-1, and bone morphogenetic protein receptor-2 were similarly altered compared with previously observed after 3-month shunting. At the RV tissue level, pro-apoptotic ratio of Bax-to-Bcl-2 expressions and caspase-3 activation were increased, along with an increase in cardiomyocyte size, while expressions in voltage-gated potassium channels (Kv1.5 and Kv2.1) and angiogenic factors (angiopoietin-2 and vascular endothelial growth factor) were decreased. Right ventricular expressions of pro-inflammatory cytokines [interleukin (IL)-1α, IL-1ß, tumour necrosis factor-α (TNF-α)] and natriuretic peptide precursors (NPPA and NPPB) were increased. There was an inverse correlation between RV Ees/Ea and pro-apoptotic Bax/Bcl-2 ratios. CONCLUSIONS: Prolonged left-to-right shunting in piglets does not further aggravate pulmonary vasculopathy, but is a cause of RV failure, which appears related to an activation of apoptosis and inflammation.

Activation of apoptotic pathways in experimental acute afterload-induced right ventricular failure.

OBJECTIVE: The pathobiology of persistent right ventricular failure observed after an acute increase in right ventricular afterload remains incompletely understood. We hypothesized that persistent right ventricular dysfunction might be related to activation of apoptotic pathways. DESIGN: Prospective, randomized, controlled animal study. SETTING: University research laboratory. SUBJECTS: Mongrel dogs. INTERVENTIONS: Fourteen anesthetized dogs were randomized to a transient 90-min pulmonary artery constriction operation to induce persistent right ventricular failure or to a sham operation followed 30 mins later by hemodynamic measurements and sampling of cardiac tissue. MEASUREMENTS AND MAIN RESULTS: We evaluated effective arterial elastance to estimate right ventricular afterload and end-systolic elastance to estimate right ventricular contractility. Transient increase in pulmonary artery pressure persistently increased effective arterial elastance from 0.75 +/- 0.08 to 1.37 +/- 0.18 mm Hg/mL and decreased end-systolic elastance from 1.06 +/- 0.09 to 0.49 +/- 0.09 mm Hg/mL, end-systolic elastance/effective arterial elastance from 1.44 +/- 0.06 to 0.34 +/- 0.03, and cardiac output from 3.78 +/- 0.16 to 1.46 +/- 0.10 L/min, indicating right ventricular failure. At the pathobiologic level, we assessed apoptosis by real-time quantitative polymerase chain reaction, Western blotting, enzyme-linked immunosorbent assay, and immunohistochemistry. As compared with the sham-operated group, and with the left ventricle in animals with persistent right ventricular failure, there were decreased right ventricular and septal expressions of Bcl-2 with no changes in expressions of Bax, resulting in an increased Bax/Bcl-2 ratio. Right ventricular and septal Bcl-XL, and right ventricular Bcl-w gene expressions were decreased as compared with the sham-operated group, whereas Bak gene expression did not change. There were activations of right ventricular caspases-8 and -9 and of right ventricular and septal caspase-3. Diffuse right ventricular and septal apoptosis was confirmed by terminal deoxynucleotidyl transferase dUTP nick-end labeling staining. There were also increased right ventricular and septal protein expressions of tumor necrosis factor-alpha. CONCLUSIONS: Acute afterload-induced persistent right ventricular failure appears to be related to an early activation of apoptotic pathways and to a local overexpression of tumor necrosis factor-alpha, a proinflammatory cytokine.