Search

Background: Pulmonary arterial hypertension (PAH) is a deadly cardiopulmonary disease with multi-organ involvement including impaired liver function. Liver dysfunction in PAH is poorly understood but significantly associated with morbidity and mortality. Hispanics have a significantly higher prevalence of non-alcoholic fatty liver disease (NAFLD) and evidence of more advanced disease in comparison to other ethnic groups. The clinical impact of NAFLD in Hispanic PAH patients is unknown. We aimed to investigate the impact of a validated scoring system, non-alcoholic fatty liver disease fibrosis (NFS) score, to predict the degree of liver fibrosis in a Hispanic PAH population and its relationship to hemodynamics, functional class, and outcomes. Methods: A retrospective review of all treatment naïve Hispanic patients with group I WHO pulmonary hypertension (PH) at a single academic center between February 2016 and March 2021 was performed. Patients with history of substance or alcohol abuse, non-group I WHO PH, pre-existent liver disease, chronic kidney disease, atrial fibrillation, thyroid disease, and warfarin use were excluded from the study. The diagnosis of group I WHO PH was determined by cardiac catheterization after the exclusion of other etiologies. NFS scores were calculated for each patient and correlated with functional capacity, hemodynamics, NT-proBNP, and survival. Results: A total of 96 Hispanic patients were included in our study. The median age of patients in our cohort was 49 (IQR 15) and 69% of our cohort were females. Higher NFS scores indicating advanced hepatic fibrosis (F3-F4) were found to correlate with elevated right-sided cardiac filling pressures, elevated levels of NT-proBNP, lower functional capacity, and worse 5-year survival rates. Conclusion: In Hispanic patients with PAH, NFS scores correlate with the degree of right sided pressure overload. In addition, advanced fibrosis scores were independently associated with lower 5-year survival rates and added prognostic information to other established risk parameters in PAH. This study suggests that screening for liver disease in this vulnerable patient population can aid in earlier detection and possible intervention, thus leading to potential improvement in survival rates.

Background: Heart failure is the leading cause of morbidity and mortality worldwide. With improved longevity, the incidence and prevalence of heart failure continue to rise with an estimated prevalence of around 26 million worldwide. Heart failure with preserved ejection fraction (HFpEF) constitutes around 50% of the total heart failure cases and is the most common cause of heart failure in the elderly population. The cost of heart failure care continues to rise with care for heart failure hospitalization taking the major bulk. The cost was around 30 billion in the US in 2012 and is projected to reach 70 billion by 2030. Objective: This study aims to provide updated pharmacotherapy of heart failure with a preserved ejection fraction (HFpEF). Methods: We performed a comprehensive literature review to examine the available pharmacotherapeutics in the management of heart failure with a preserved ejection fraction using online databases (PubMed and Embase). Results: We reviewed multiple studies examining pharmacotherapeutics in the management of HFpEF and reducing heart failure hospitalizations in this cohort. Until recently, our management mainly focused on aggressively managing diabetes, hypertension, atrial fibrillation, and coronary artery disease anticipating improving the outcome. Beta-blockers, Angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, sildenafil, digoxin, vericiguat, praliciguat, and Ivabradine did not improve heart failure hospitalization in this cohort. Conclusion: EMPEROR-PRESERVED (Empagliflozin) and PRESERVED-HF (Dapagliflozin) results in the management of HFpEF look promising irrespective of diabetes status. Sacubitril-valsartan and Empagliflozon are the only medications approved for its management as per the PARAGON-HF and EMPEROR-PRESERVED studies respectively.

Pulmonary arterial hypertension (PH) and chronic kidney disease (CKD) both profoundly impact patient outcomes, whether as primary disease states or as co-morbid conditions. PH is a common co-morbidity in CKD and vice versa. A growing body of literature describes the epidemiology of PH secondary to chronic kidney disease and end-stage renal disease (ESRD) (WHO group 5 PH). But, there are only limited data on the epidemiology of kidney disease in group 1 PH (pulmonary arterial hypertension [PAH]). The purpose of this review is to summarize the current data on epidemiology and discuss potential disease mechanisms and management implications of kidney dysfunction in PAH. Kidney dysfunction, determined by serum creatinine or estimated glomerular filtration rate, is a frequent co-morbidity in PAH and impaired kidney function is a strong and independent predictor of mortality. Potential mechanisms of PAH affecting the kidneys are increased venous congestion, decreased cardiac output, and neurohormonal activation. On a molecular level, increased TGF-β signaling and increased levels of circulating cytokines could have the potential to worsen kidney function. Nephrotoxicity does not seem to be a common side effect of PAH-targeted therapy. Treatment implications for kidney disease in PAH include glycemic control, lifestyle modification, and potentially Renin-Angiotensin-Aldosterone System (RAAS) blockade.

Low-grade albuminuria, determined by the urinary albumin to creatinine ratio, has been linked to systemic vascular dysfunction and is associated with cardiovascular mortality. Pulmonary arterial hypertension is related to mutations in the bone morphogenetic protein receptor type 2, pulmonary vascular dysfunction and is increasingly recognized as a systemic disease. In a total of 283 patients (two independent cohorts) diagnosed with pulmonary arterial hypertension, 18 unaffected BMPR2 mutation carriers and 68 healthy controls, spot urinary albumin to creatinine ratio and its relationship to demographic, functional, hemodynamic and outcome data were analyzed. Pulmonary arterial hypertension patients and unaffected BMPR2 mutation carriers had significantly elevated urinary albumin to creatinine ratios compared with healthy controls ( P

Pulmonary arterial hypertension is characterized by endothelial dysregulation, but global changes in gene expression have not been related to perturbations in function.RNA sequencing was used to discriminate changes in transcriptomes of endothelial cells cultured from lungs of patients with idiopathic pulmonary arterial hypertension versus control subjects and to assess the functional significance of major differentially expressed transcripts.The endothelial transcriptomes from the lungs of seven control subjects and six patients with idiopathic pulmonary arterial hypertension were analyzed. Differentially expressed genes were related to bone morphogenetic protein type 2 receptor (BMPR2) signaling. Those down-regulated were assessed for function in cultured cells and in a transgenic mouse.Fold differences in 10 genes were significant (P 0.05), four increased and six decreased in patients versus control subjects. No patient was mutant for BMPR2. However, knockdown of BMPR2 by siRNA in control pulmonary arterial endothelial cells recapitulated 6 of 10 patient-related gene changes, including decreased collagen IV (COL4A1, COL4A2) and ephrinA1 (EFNA1). Reduction of BMPR2-regulated transcripts was related to decreased β-catenin. Reducing COL4A1, COL4A2, and EFNA1 by siRNA inhibited pulmonary endothelial adhesion, migration, and tube formation. In mice null for the EFNA1 receptor, EphA2, versus control animals, vascular endothelial growth factor receptor blockade and hypoxia caused more severe pulmonary hypertension, judged by elevated right ventricular systolic pressure, right ventricular hypertrophy, and loss of small arteries.The novel relationship between BMPR2 dysfunction and reduced expression of endothelial COL4 and EFNA1 may underlie vulnerability to injury in pulmonary arterial hypertension.

The loss of a functional microvascular bed in rejecting solid organ transplants is correlated with fibrotic remodeling and chronic rejection; in lung allografts, this pathology is predicted by bronchoalveolar fluid neutrophilia which suggests a role for polymorphonuclear cells in microcirculatory injury. In a mouse orthotopic tracheal transplant model, cyclosporine, which primarily inhibits T cells, failed as a monotherapy for preventing microvessel rejection and graft ischemia. To target neutrophil action that may be contributing to vascular injury, we examined the effect of a neutrophil elastase inhibitor, elafin, on the microvascular health of transplant tissue. We showed that elafin monotherapy prolonged microvascular perfusion and enhanced tissue oxygenation while diminishing the infiltration of neutrophils and macrophages and decreasing tissue deposition of complement C3 and the membrane attack complex, C5b-9. Elafin was also found to promote angiogenesis through activation of the extracellular signal-regulated kinase (ERK) signaling pathway but was insufficient as a single agent to completely prevent tissue ischemia during acute rejection episodes. However, when combined with cyclosporine, elafin effectively preserved airway microvascular perfusion and oxygenation. The therapeutic strategy of targeting neutrophil elastase activity alongside standard immunosuppression during acute rejection episodes may be an effective approach for preventing the development of irreversible fibrotic remodeling.

Rationale: Systemic sclerosis (SSc)-associated pulmonary arterial hypertension (PAH) portends worse outcome than other forms of PAH. Vasoconstrictive and vascular remodeling actions of endothelin (ET) 1 and angiotensin (Ang) II via endothelin receptor type A (ETAR) and Ang receptor type-1 (AT1R) activation are implicated in PAH pathogenesis.Objectives: We hypothesized that stimulating autoantibodies (Abs) targeting and activating AT1R and ETAR may contribute to SSc-PAH pathogenesis, and tested their functional and biomarker relevance.Methods: Anti-AT1R and -ETAR Abs were detected by ELISA in different cohorts of patients and tested in vitro and in an animal model for their pathophysiological effects.Measurements and Main Results: The Abs were significantly higher and more prevalent in patients with SSc-PAH (n = 81) and connective tissue disease–associated PAH (n = 110) compared with other forms of PAH/pulmonary hypertension (n = 106). High anti-AT1R and anti-ETAR Abs predicted development of SSc-PAH and S...

Reduced expression of bone morphogenetic protein receptor 2 subverts a stress granule response, heightens GM-CSF mRNA translation, and increases inflammatory cell recruitment to exacerbate pulmonary arterial hypertension., Idiopathic pulmonary arterial hypertension (PAH [IPAH]) is an insidious and potentially fatal disease linked to a mutation or reduced expression of bone morphogenetic protein receptor 2 (BMPR2). Because intravascular inflammatory cells are recruited in IPAH pathogenesis, we hypothesized that reduced BMPR2 enhances production of the potent chemokine granulocyte macrophage colony-stimulating factor (GM-CSF) in response to an inflammatory perturbation. When human pulmonary artery (PA) endothelial cells deficient in BMPR2 were stimulated with tumor necrosis factor (TNF), a twofold increase in GM-CSF was observed and related to enhanced messenger RNA (mRNA) translation. The mechanism was associated with disruption of stress granule formation. Specifically, loss of BMPR2 induced prolonged phospho-p38 mitogen-activated protein kinase (MAPK) in response to TNF, and this increased GADD34–PP1 phosphatase activity, dephosphorylating eukaryotic translation initiation factor (eIF2α), and derepressing GM-CSF mRNA translation. Lungs from IPAH patients versus unused donor controls revealed heightened PA expression of GM-CSF co-distributing with increased TNF and expanded populations of hematopoietic and endothelial GM-CSF receptor α (GM-CSFRα)–positive cells. Moreover, a 3-wk infusion of GM-CSF in mice increased hypoxia-induced PAH, in association with increased perivascular macrophages and muscularized distal arteries, whereas blockade of GM-CSF repressed these features. Thus, reduced BMPR2 can subvert a stress granule response, heighten GM-CSF mRNA translation, increase inflammatory cell recruitment, and exacerbate PAH.

In February 2018, the 6th World Symposium on Pulmonary Hypertension (WSPH) brought together experts from various disciplines to review the most relevant clinical and scientific advances in the field of PH over the last 5 years. Based on careful review and discussions by members of the different task forces, major revisions were made on the hemodynamic definition for various forms of PH and new genes were added to the list of genetic markers associated with pulmonary arterial hypertension (PAH) and pulmonary veno-occlusive disease. In addition, the use of risk stratification tools was encouraged as a strategy to reduce one-year mortality risk in PAH patients through early implementation of PAH therapies. While members of the medical community are still debating some of the proposed changes, the new WSPH guidelines advocate early diagnosis and initiation of combination therapy to reduce mortality and improve quality of life in patients with PH.

Summary: Using proteomic approaches, we uncovered a DNA damage response (DDR) function for peroxisome proliferator activated receptor γ (PPARγ) through its interaction with the DNA damage sensor MRE11-RAD50-NBS1 (MRN) and the E3 ubiquitin ligase UBR5. We show that PPARγ promotes ATM signaling and is essential for UBR5 activity targeting ATM interactor (ATMIN). PPARγ depletion increases ATMIN protein independent of transcription and suppresses DDR-induced ATM signaling. Blocking ATMIN in this context restores ATM activation and DNA repair. We illustrate the physiological relevance of PPARγ DDR functions by using pulmonary arterial hypertension (PAH) as a model that has impaired PPARγ signaling related to endothelial cell (EC) dysfunction and unresolved DNA damage. In pulmonary arterial ECs (PAECs) from PAH patients, we observed disrupted PPARγ-UBR5 interaction, heightened ATMIN expression, and DNA lesions. Blocking ATMIN in PAH PAEC restores ATM activation. Thus, impaired PPARγ DDR functions may explain the genomic instability and loss of endothelial homeostasis in PAH. : Li et al. identify PPARγ interactions with MRN and UBR5. PPARγ promotes UBR5-mediated ATMIN degradation, necessary for ATM activation upon DNA damage. Pulmonary arterial hypertension (PAH) endothelial cells exhibit genomic instability and disrupted PPARγ-UBR5 interaction. Blocking ATMIN restores ATM signaling in these cells, highlighting the significance of the PPARγ-ATMIN axis. Keywords: PPARγ, DNA damage, vascular biology, pulmonary hypertension, endothelial cells, ATM, MRN

Background Atrial flutter and fibrillation are being increasingly reported in patients with pulmonary hypertension but little is known about their clinical implications. We sought to determine the incidence and clinical impact of these arrhythmias in patients with pulmonary hypertension. Methods In a 5-year, prospective study, we assessed the incidence of new-onset atrial flutter and fibrillation as well as risk factors, clinical consequences, management, and impact on survival in patients with pulmonary arterial hypertension (PAH, n=157) or inoperable chronic thromboembolic pulmonary hypertension (CTEPH, n=82). Results The cumulative 5-year incidence of new-onset atrial flutter and fibrillation was 25.1% (95% confidence interval, 13.8–35.4%). The development of these arrhythmias was frequently accompanied by clinical worsening (80%) and signs of right heart failure (30%). Stable sinus rhythm was successfully re-established in 21/24 (88%) of patients initially presenting with atrial flutter and in 16/24 (67%) of patients initially presenting with atrial fibrillation. New-onset atrial flutter and fibrillation were an independent risk factor of death (p=0.04, simple Cox regression analysis) with a higher mortality in patients with persistent atrial fibrillation when compared to patients in whom sinus rhythm was restored (estimated survival at 1, 2 and 3years 64%, 55%, and 27% versus 97%, 80%, and 57%, respectively; p=0.01, log rank analysis). Conclusions Atrial flutter and fibrillation develop in a sizable number of patients with PAH or inoperable CTEPH and often lead to clinical deterioration and right heart failure. Mortality is high when sinus rhythm cannot be restored.

Rationale: Pulmonary hypertension (PH) is characterized by progressive elevation in pulmonary pressure and loss of small pulmonary arteries. As bone morphogenetic proteins promote pulmonary angiogenesis by recruiting the Wnt/β-catenin pathway, we proposed that β-catenin activation could reduce loss and induce regeneration of small pulmonary arteries (PAs) and attenuate PH. Objective: This study aims to establish the role of β-catenin in protecting the pulmonary endothelium and stimulating compensatory angiogenesis after injury. Methods and Results: To assess the impact of β-catenin activation on chronic hypoxia-induced PH, we used the adenomatous polyposis coli ( Apc Min/+ ) mouse, where reduced APC causes constitutive β-catenin elevation. Surprisingly, hypoxic Apc Min/+ mice displayed greater PH and small PA loss compared with control C57Bl6J littermates. PA endothelial cells isolated from Apc Min/+ demonstrated reduced survival and angiogenic responses along with a profound reduction in adhesion to laminin. The mechanism involved failure of APC to interact with the cytoplasmic domain of the α3 integrin, to stabilize focal adhesions and activate integrin-linked kinase-1 and phospho Akt. We found that PA endothelial cells from lungs of patients with idiopathic PH have reduced APC expression, decreased adhesion to laminin, and impaired vascular tube formation. These defects were corrected in the cultured cells by transfection of APC. Conclusions: We show that APC is integral to PA endothelial cells adhesion and survival and is reduced in PA endothelial cells from PH patient lungs. The data suggest that decreased APC may be a cause of increased risk or severity of PH in genetically susceptible individuals.

Background Recent studies have revealed that microRNAs (miRNAs) play a key role in the control of angiogenesis and vascular remodeling. Specific miRNAs in plexiform vasculopathy of severe pulmonary arterial hypertension (PAH) in humans have not yet been investigated. Methods We analyzed expression of miR-143/145 (vascular smooth muscle–specific), miR-126 (endothelial-specific) and related mRNAs in plexiform (PLs) and concentric lesions (CLs), which had been laser-microdissected from specimens of formalin-fixed, paraffin-embedded, explanted lungs of PAH patients ( n = 12) and unaffected controls ( n = 8). Samples were analyzed by real-time polymerase chain reaction, and protein expression was determined by immunohistochemistry. Results Expression levels of miR-143/145 and its target proteins (e.g., myocardin, smooth muscle myosin heavy chain) were found to be significantly higher in CLs than in PLs, whereas miR-126 and VEGF-A were significantly up-regulated in PLs when compared with CLs, indicating a more prominent angiogenic phenotype of PL. This correlates with a down-regulation of miR-204 as well as an up-regulation of miR-21 in PLs, which in turn corresponds to enhanced cell proliferation. Conclusions Our findings show that morphologic changes of plexiform vasculopathy in the end-stage PAH lung are reflected by alterations at the miRNA level.

Current guidelines for the treatment of patients with idiopathic pulmonary arterial hypertension (IPAH) recommend basing therapeutic decision-making on haemodynamic, functional and biochemical variables. Most of these parameters have been evaluated as risk predictors at the time of diagnosis. The aim of the present study was to assess the prognostic impact of changes in these parameters after initiation of targeted therapy. A cohort of 109 patients with IPAH who had undergone haemodynamic, functional and biochemical assessments at baseline and 3-12 months after initiation of pulmonary arterial hypertension (PAH)-targeted therapy, were followed for a median 38 months in order to determine predictors of mortality at baseline and during the course of their disease. Within the observation period, 53 (48.6%) patients died and four (3.7%) underwent lung transplantation. Kaplan-Meier estimates for transplantation-free survival were 92%, 67%, and 51% at 1, 3, and 5 yrs, respectively. Among baseline variables, 6-min walk distance, right atrial pressure, cardiac index, mixed-venous oxygen saturation (S(v,O(2))) and N-terminal-pro brain natriuretic peptide (NT-proBNP) were independent predictors of survival. During follow-up, changes in World Health Organization functional class, cardiac index, S(v,O(2)) and NT-proBNP proved significant predictors of outcome. When assigned to prognostic groups, improvements as well as deteriorations in these parameters after initiation of PAH-targeted therapy had a strong impact on survival. Measurements obtained at follow-up had a higher predictive value than variables obtained at baseline. Changes in established predictors of outcome during the course of the disease provide important prognostic information in patients with IPAH.

Pulmonary arterial hypertension (PAH) is a debilitating disease with a high mortality rate. A hallmark of PAH is plexiform lesions (PLs), complex vascular formations originating from remodeled pulmonary arteries. The development and significance of these lesions have been debated and are not yet fully understood. Some features of PLs resemble neoplastic disorders, and there is a striking resemblance to glomeruloid-like lesions (GLLs) in glioblastomas. To further elucidate PLs, we used in situ methods, such as (fluorescent) IHC staining, three-dimensional reconstruction, and laser microdissection, followed by mRNA expression analysis. We generated compartment-specific expression patterns in the lungs of 25 patients (11 with PAH associated with systemic shunts, 6 with idiopathic PAH, and 8 controls) and GLLs from 5 glioblastomas. PLs consisted of vascular channels lined by a continuously proliferating endothelium and backed by a uniform myogenic interstitium. They also showed up-regulation of remodeling-associated genes, such as HIF1a, TGF-β1, VEGF-α, VEGFR-1/-2, Ang-1, Tie-2, and THBS1, but also of cKIT and sprouting-associated markers, such as NOTCH and matrix metalloproteinases. The cellular composition and signaling seen in GLLs in neural neoplasms differed significantly from those in PLs. In conclusion, PLs show a distinct cellular composition and microenvironment, which contribute to the plexiform phenotype and set them apart from other processes of vascular remodeling in patients with PAH. Neoplastic models of angiogenesis seem to be of limited use in further study of plexiform vasculopathy.

Osteopontin (OPN) is a pleiotropic cytokine that has been postulated to play a role in the pathogenesis of idiopathic pulmonary arterial hypertension (IPAH). OPN plasma levels may be related to disease severity and mortality in patients with PAH.OPN plasma levels obtained during right-sided heart catheterization were assessed by a commercially available enzyme-linked immunosorbent assay and related to hemodynamics, exercise capacity, N-terminal pro-brain natriuretic peptide (NT-pro-BNP) level, uric acid level, C-reactive protein level, and survival in two cohorts of patients with IPAH: a 4-year retrospective cohort (n = 70) and a prospective cohort (n = 25) followed for 3 months after initiation of therapy. Forty apparently healthy individuals served as control subjects.Baseline OPN levels were elevated in patients with IPAH compared with healthy control subjects (50.2 ± 35.9 vs 23.7 ± 2.8 ng/mL, P.0001). In the retrospective as well as in the prospective cohort, OPN levels correlated with mean right atrial pressure and NT-BNP. In the retrospective cohort, OPN levels also correlated with age (r = 0.3, P = .02), 6-min walking distance (r=-0.4, P = .05), and New York Heart Association class (r = 0.4, P = .001). Multivariate Cox analysis demonstrated that baseline OPN levels were independent predictors of mortality (P = .02). When patients were divided according to their baseline OPN values, being normal or elevated at baseline (below or above 34.5 ng/mL), proportional survival rates were 100% vs 80% after 1 year and 77% vs 51% after 3 years, respectively.Circulating OPN predicts survival in patients with IPAH and is associated with a higher New York Heart Association class. OPN, thus, may be useful as a biomarker in IPAH.

Growth-differentiation factor (GDF)-15 is a stress-responsive, transforming growth factor-beta-related cytokine. Circulating levels of GDF-15 provide independent prognostic information in patients with acute pulmonary embolism and chronic left-sided heart failure.To assess the prognostic value of GDF-15 in idiopathic pulmonary arterial hypertension.GDF-15 levels were determined in 76 treatment-naive patients at the time of baseline right heart catheterization. Patients were monitored for a median (range) of 48 (0-101) months (first cohort). Twenty-two additional patients were studied at baseline and 3 to 6 months after initiation of therapy (second cohort).Fifty-five percent of the patients in the first cohort presented with GDF-15 levels above 1,200 ng/L, the previously defined upper reference limit. The risk of death or transplantation at 3 years was 15 and 44% in patients with GDF-15 levels below or above 1,200 ng/L, respectively (P = 0.006). Elevated levels of GDF-15 were associated with increased mean right atrial and pulmonary capillary wedge pressures, a lower mixed venous oxygen saturation (Sv(O(2))), and higher levels of uric acid and N-terminal pro-brain natriuretic peptide (NT-proBNP). After adjustment for hemodynamic and biochemical variables, GDF-15 remained an independent predictor of adverse outcomes (P = 0.002). GDF-15 provided prognostic information in clinically relevant patient subgroups, and added prognostic information to hemodynamic variables and NT-proBNP. Changes in GDF-15 over time in the second cohort were related to changes in NT-proBNP (P = 0.031) and inversely related to changes in Sv(O(2)) (P0.001).GDF-15 is a promising new biomarker in idiopathic pulmonary arterial hypertension.

Rationale: Pulmonary arterial hypertension is characterized by endothelial dysfunction, impaired bone morphogenetic protein receptor 2 (BMPR2) signaling, and increased elastase activity. Synthetic elastase inhibitors reverse experimental pulmonary hypertension but cause hepatotoxicity in clinical studies. The endogenous elastase inhibitor elafin attenuates hypoxic pulmonary hypertension in mice, but its potential to improve endothelial function and BMPR2 signaling, and to reverse severe experimental pulmonary hypertension or vascular pathology in the human disease was unknown.Objectives: To assess elafin-mediated regression of pulmonary vascular pathology in rats and in lung explants from patients with pulmonary hypertension. To determine if elafin amplifies BMPR2 signaling in pulmonary artery endothelial cells and to elucidate the underlying mechanism.Methods: Rats with pulmonary hypertension induced by vascular endothelial growth factor receptor blockade and hypoxia (Sugen/hypoxia) as well as lung organ...

SummaryMitochondrial dysfunction, inflammation, and mutant bone morphogenetic protein receptor 2 (BMPR2) are associated with pulmonary arterial hypertension (PAH), an incurable disease characterized by pulmonary arterial (PA) endothelial cell (EC) apoptosis, decreased microvessels, and occlusive vascular remodeling. We hypothesized that reduced BMPR2 induces PAEC mitochondrial dysfunction, promoting a pro-inflammatory or pro-apoptotic state. Mice with EC deletion of BMPR2 develop hypoxia-induced pulmonary hypertension that, in contrast to non-transgenic littermates, does not reverse upon reoxygenation and is associated with reduced PA microvessels and lung EC p53, PGC1α and TFAM, regulators of mitochondrial biogenesis, and mitochondrial DNA. Decreasing PAEC BMPR2 by siRNA during reoxygenation represses p53, PGC1α, NRF2, TFAM, mitochondrial membrane potential, and ATP and induces mitochondrial DNA deletion and apoptosis. Reducing PAEC BMPR2 in normoxia increases p53, PGC1α, TFAM, mitochondrial membrane potential, ATP production, and glycolysis, and induces mitochondrial fission and a pro-inflammatory state. These features are recapitulated in PAECs from PAH patients with mutant BMPR2.

We conducted an international, prospective, 3-year questionnaire-based survey among 11 pulmonary hypertension centres to assemble data from patients with pulmonary arterial hypertension (PAH) undergoing noncardiac and nonobstetric surgery. Data were collected between July 2007 and June 2010 from 114 patients with PAH (70% female, mean age 57 years) who underwent major surgery. At the time of surgery, 43% were in functional class III/IV. 82% of the interventions were performed under general anaesthesia and 18% under spinal anaesthesia. Major complications occurred in seven (6.1%) of the patients, of whom four died, resulting in an overall perioperative mortality rate of 3.5%. The mortality rate was 15% (two out of 13) in emergency procedures, compared with 2% (two out of 101) in nonemergency procedures (p=0.01). Risk factors for major complications were an elevated right atrial pressure (OR 1.1, 95% CI 1.0-1.3; p=0.01), a 6-min walking distance

Background Growth-differentiation factor-15 (GDF-15) is a stress-responsive, transforming growth factor-β-related cytokine, which has recently been reported to be elevated in serum of patients with idiopathic pulmonary arterial hypertension (IPAH). The aim of the study was to examine the expression and biological roles of GDF-15 in the lung of patients with pulmonary arterial hypertension (PAH). Methods GDF-15 expression in normal lungs and lung specimens of PAH patients were studied by real-time RT-PCR and immunohistochemistry. Using laser-assisted micro-dissection, GDF-15 expression was further analyzed within vascular compartments of PAH lungs. To elucidate the role of GDF-15 on endothelial cells, human pulmonary microvascular endothelial cells (HPMEC) were exposed to hypoxia and laminar shear stress. The effects of GDF-15 on the proliferation and cell death of HPMEC were studied using recombinant GDF-15 protein. Results GDF-15 expression was found to be increased in lung specimens from PAH patients, com-pared to normal lungs. GDF-15 was abundantly expressed in pulmonary vascular endothelial cells with a strong signal in the core of plexiform lesions. HPMEC responded with marked upregulation of GDF-15 to hypoxia and laminar shear stress. Apoptotic cell death of HPMEC was diminished, whereas HPMEC proliferation was either increased or decreased depending of the concentration of recombinant GDF-15 protein. Conclusions GDF-15 expression is increased in PAH lungs and appears predominantly located in vascular endothelial cells. The expression pattern as well as the observed effects on proliferation and apoptosis of pulmonary endothelial cells suggest a role of GDF-15 in the homeostasis of endothelial cells in PAH patients.

Pulmonary arterial hypertension (PAH) is a debilitating disease with a high mortality rate. A hallmark of PAH is plexiform lesions (PLs), complex vascular formations originating from remodeled pulmonary arteries. The development and significance of these lesions have been debated and are not yet fully understood. Some features of PLs resemble neoplastic disorders, and there is a striking resemblance to glomeruloid-like lesions (GLLs) in glioblastomas. To further elucidate PLs, we used in situ methods, such as (fluorescent) IHC staining, three-dimensional reconstruction, and laser microdissection, followed by mRNA expression analysis. We generated compartment-specific expression patterns in the lungs of 25 patients (11 with PAH associated with systemic shunts, 6 with idiopathic PAH, and 8 controls) and GLLs from 5 glioblastomas. PLs consisted of vascular channels lined by a continuously proliferating endothelium and backed by a uniform myogenic interstitium. They also showed up-regulation of remodeling-associated genes, such as HIF1a, TGF-β1, VEGF-α, VEGFR-1/-2, Ang-1, Tie-2, and THBS1, but also of cKIT and sprouting-associated markers, such as NOTCH and matrix metalloproteinases. The cellular composition and signaling seen in GLLs in neural neoplasms differed significantly from those in PLs. In conclusion, PLs show a distinct cellular composition and microenvironment, which contribute to the plexiform phenotype and set them apart from other processes of vascular remodeling in patients with PAH. Neoplastic models of angiogenesis seem to be of limited use in further study of plexiform vasculopathy.

To determine the diagnostic utility of circulating angiopoietin-1 (Ang-1) and its antagonist angiopoietin-2 (Ang-2) as potential biomarkers of disease severity or response to treatment in idiopathic pulmonary arterial hypertension (IPAH). Imbalances in angiogenic factors including vascular endothelial cell growth factor (VEGF) and the angiopoetin-Tie2 receptor system have been implicated in the pathogenesis of IPAH.Plasma Ang-1, Ang-2, soluble Tie2 (sTie2), and VEGF were determined by in-house immunoassays in two cohorts of IPAH patients: a retrospective cohort (n = 81) and a prospective cohort (n = 25). Ten patients with normal pulmonary artery pressures and 14 apparently healthy subjects served as controls. Plasma levels of all angiogenic factors were elevated in IPAH patients compared with controls (all P0.005). Angiopoietin-2, but not Ang-1, sTie2, and VEGF correlated with cardiac index (r = -0.53, P0.001), pulmonary vascular resistance (PVR) (r= 0.60, P0.001), and mixed venous oxygen saturation (SvO(2)) (r= -0.63, P0.001). In multivariate analysis, elevated Ang-2 was an independent risk factor of mortality (P = 0.004). The patients in the prospective cohort were studied longitudinally at baseline and 3 months after initiation of therapy. Changes in Ang-2 after initiation of therapy correlated with changes in mean right atrial pressure (r = 0.6, P = 0.008), PVR (r = 0.51, P = 0.04), and inversely related to changes in SvO(2) (r = -0.75, P0.001). Histological studies showed that the expression of Ang-2 mRNA and protein was up-regulated in plexiform lesions from IPAH lung tissue samples.Ang-2 may be involved in the pathogenesis of IPAH, and plasma Ang-2 might serve as a promising new biomarker of disease severity and response to treatment in patients with IPAH.

There is limited data on the long-term efficacy of intravenous iloprost in patients with pulmonary arterial hypertension (PAH). This retrospective multicentre analysis evaluated the clinical course of patients with PAH treated with i.v. iloprost, in most cases after having received inhaled iloprost as first-line therapy. Between 1997 and 2001, 79 PAH patients were treated with i.v. iloprost and followed until 2007. These patients had advanced and progressive disease as indicated by a mean pulmonary vascular resistance of 1,533 dyn x s x cm(-5) at the time of diagnosis and of 1,858 dyn x s x cm(-5) at the onset of i.v. iloprost therapy. Introduction of i.v. iloprost therapy resulted in initial haemodynamic and clinical improvement. At the end of the observation period, however, 50 (61%) patients had died and 21 (26%) required lung transplantation. Transplantation-free survival rates at 1, 3, and 5 yrs were 86%, 59% and 45%, respectively, after the diagnosis of PAH, and 54%, 31% and 15%, respectively, after the introduction of i.v. iloprost therapy. Predictors of an adverse outcome at baseline were a low 6-min walk distance and a low mixed venous oxygen saturation. In conclusion, despite initial haemodynamic and clinical improvement, overall long-term survival with i.v. iloprost therapy was limited.

Background The majority of patients with idiopathic pulmonary arterial hypertension (IPAH) in functional classes II and III are currently being treated with non-parenteral therapies, including endothelin receptor antagonists (ERA), phosphodiesterase (PDE)-5 inhibitors, inhaled iloprost or combinations of these substances. If these treatments fail, current guidelines recommend the addition of parenteral prostanoid therapy. There is, however, limited evidence for the efficacy of parenteral prostanoids when added to combinations of non-parenteral therapies. Methods In this retrospective, multicentre study we collected data from consecutive IPAH patients receiving intravenous iloprost in addition to optimized non-parenteral therapy between Jan 2002 and Dec 2009. Analyses included 6 min walk distance (6MWD), functional class, need for transplantation, and survival. Results During the observation period, 50 patients were treated with intravenous iloprost in addition to non-parenteral therapy; 44% of the patients were on dual combination therapy and 52% on triple combination. Three months after initiation of iloprost, functional class had improved in 24% of the patients and the median 6MWD had increased from 289 m to 298 m (n.s.). During the observation period, 22 patients (44%) died and 14 (28%) underwent lung transplantation. The probabilities of LuTx-free survival at 1, 3 and 5 years following iloprost initiation were 38%, 17% and 17%, respectively. A 6MWD < 300 m and persistent functional class IV at 3 months after initiation of intravenous iloprost were predictors of an adverse outcome. Conclusion In essence, late initiation of intravenous iloprost in IPAH patients who previously failed to respond to non-parenteral therapies appears to be of limited efficacy in the majority patients. Alternative therapeutic options are currently not available, underlying the need for the development of new drugs.

Objective To determine the levels of circulating copeptin in patients with pulmonary arterial hypertension (PAH), and to evaluate its relation with disease severity, outcome and response to treatment. Background Vasopressin is a key regulator of body fluid homeostasis. The co-secreted protein copeptin serves as surrogate for plasma vasopressin levels and increases in acute and chronic left ventricular dysfunction. Copeptin has not been studied in PAH. Methods Serum copeptin levels were evaluated in a retrospective cohort of 92 treatment-naïve patients with PAH, 39 patients with normal right ventricular hemodynamics (diseased controls) and 14 apparently healthy individuals (healthy controls). In a second prospective cohort of 15 patients with PAH, serial changes of copeptin levels after initiation of PAH treatment were measured. Copeptin levels were compared with clinical, biochemical and hemodynamic parameters as well as response to treatment and clinical outcome. Results Circulating copeptin levels were elevated in PAH patients compared to diseased controls (20.1 pmol/l vs. 5.1 pmol/l; p = 0.001). Baseline levels of copeptin correlated with NYHA functional class (r = 0.46; p = 0.01), 6 minute walking distance (r = -0.26; p = 0.04), NT-proBNP (r = 0.49, p = 0.01), creatinine (r = 0.39, p = 0.01) and estimated glomerular filtration rate (r = -0.32, p = 0.01). Copeptin levels did not correlate with hemodynamics but decreased after initiation of PAH therapy (p = 0.001). Elevated copeptin levels were associated with shorter survival (p