Vasile Foris

Biomarkers in Pulmonary Hypertension : What Do We Know?

Pulmonary hypertension (PH) is a hemodynamic condition that has a poor prognosis and can lead to right-sided heart failure. It may result from common diseases such as left-sided heart or lung disease or may present as the rare entity of idiopathic pulmonary arterial hypertension. Biomarkers that specifically indicate the pathologic mechanism, the severity of the disease, and the treatment response would be ideal tools for the management of PH. In this review, markers related to heart failure, inflammation, hemostasis, remodeling, and endothelial cell-smooth muscle cell interaction are discussed, and their limitations are emphasized. Anemia, hypocarbia, elevated uric acid, and C-reactive protein levels are unspecific markers of disease severity. Brain natriuretic peptide and N-terminal fragment of pro-brain natriuretic peptide have been recommended in current guidelines, whereas other prognostic markers, such as growth differentiation factor-15, osteopontin, and red cell distribution width, are emerging. Chemokines of the CC family and matrix metalloproteases have been linked to the vascular pathologic mechanisms, and new markers such as apelin have been described. Circulating endothelial and progenitor cells have received much attention as markers of disease activity, but with controversial findings. A lack of standards for cell isolation and characterization methods and differences in the pathologic mechanisms of the investigated patients may have contributed to the discrepancies. In conclusion, although several promising markers have been identified over the past few years, the development of more specific markers, standardization, and prospective validation are warranted.

Characterization of Patients With Borderline Pulmonary Arterial Pressure

BACKGROUND Resting mean pulmonary artery pressure (mPAP) values between 20 and 25 mm Hg are above normal but do not fulfill the criteria for pulmonary hypertension (PH). The clinical relevance of such borderline hemodynamics is a matter of discussion. METHODS We focused on patients who underwent right-sided heart catheterization during rest and exercise for symptoms indicative of PH or due to underlying disease associated with an increased risk for pulmonary arterial hypertension and characterized the patients according to their resting mPAP. Patients with manifest PH (mPAP ≥ 25 mm Hg) were excluded. RESULTS We included 141 patients, 32 of whom presented with borderline hemodynamics (20 < mPAP < 25 mm Hg). Borderline patients were older (65.8 ± 12.5 years vs 57.3 ± 12.5 years, P = .001) and more often had cardiac comorbidities (53% vs 15%, P < .001) or decreased lung function (47% vs 16%, P < .001) as compared with patients with resting mPAP < 21 mm Hg. After correction for age, borderline patients had significantly increased pulmonary vascular resistance (2.7 ± 0.7 Wood units vs 1.8 ± 0.8 Wood units, P < .001) and mPAP/cardiac output (CO) and transpulmonary gradient/CO slopes (both P < .001) as well as lower peak oxygen uptake (16.9 ± 4.6 mL/min/kg vs 20.9 ± 4.7 mL/min/kg, P = .009) and 6-min walk distance (383 ± 120 m vs 448 ± 92 m, P = .001). During follow-up (4.4 ± 1.4 years), the mortality rate of borderline patients vs patients with resting mPAP < 21 mm Hg was 19% vs 4%. CONCLUSIONS In patients undergoing right-sided heart catheterization with exclusion of manifest PH, borderline elevation of pulmonary arterial pressure is associated with cardiac and pulmonary comorbidities, decreased exercise capacity, and a poor prognosis.

Changes in pulmonary exercise haemodynamics in scleroderma: a 4-year prospective study

Pulmonary arterial hypertension (PAH) is a feared complication of systemic sclerosis. In this prospective cohort study, we monitored the changes in resting and exercise pulmonary haemodynamics of scleroderma patients without initial PAH over a mean follow-up period of ∼4 years. All patients underwent exercise echocardiography and cardiopulmonary exercise testing at baseline and follow-up. A subgroup underwent exercise right heart catheter (RHC) investigations. The primary end-point was the echocardiographic systolic pulmonary arterial pressure at 50 W exercise (sPAP50). We included 99 patients, of whom 58 had a complete dataset. Three out of 99 patients developed RHC-confirmed PAH (0.75 cases per 100 patient-years). sPAP50 increased (p<0.001) and peak oxygen uptake (secondary end-point) decreased significantly (p=0.001) during follow-up, but there was no significant change in resting sPAP (p=0.38). In the RHC subgroup (n=28), mean (m)PAP and pulmonary vascular resistance at 50 W increased significantly (p=0.02 and p=0.002, respectively), but resting mPAP was unchanged. Scleroderma patients without PAH develop a mild but significant deterioration of pulmonary exercise haemodynamics and exercise capacity over a 4-year follow-up period, indicating a progression of pulmonary vascular disease. The manifestation rate of RHC-confirmed PAH was 0.75 cases per 100 patient-years. Scleroderma patients without pulmonary hypertension develop mild deterioration in pulmonary exercise haemodynamics http://ow.ly/hva930aEW4E

PL-7 Positive Antisynthetase Syndrome and Pulmonary Hypertension

To the Editor: Antisynthetase syndrome is characterized by interstitial lung disease (ILD), myositis, arthropathy, fever, Raynaud phenomenon, and mechanic’s hands. The morbidity of the syndrome is usually due to lung involvement1. In January 2005, a 65-year-old female nonsmoking patient presented to our outpatient clinic with fever (38.5°C), unproductive cough, shortness of breath, dry throat, nocturnal sweating, and weight loss (3–4 kg). Previously, she was exposed to passive cigarette smoke and cleaning chemicals. Essential hypertension treated by bisoprolol and an allergy to contrast material were known. There was no positive family history for rheumatic or cardiovascular disease. Electrocardiogram was normal but lung function test showed a restrictive pattern [forced vital capacity (FVC) 52%, forced expiratory volume (FEV)1 56.3%, FEV1/FVC 85.1%]. Carbon monoxide diffusion capacity measurement was not feasible because of the decreased vital capacity. Glomerular filtration rate was slightly reduced (48 ml/min). Other variables were elevated: C-reactive protein 18 mg/l (normal < 5 mg/dl), creatine kinase (CK) 1402 U/l, CK-myocardial band 45 U/l, lactate dehydrogenase 335 U/l, and pro-brain natriuretic peptide (NT-proBNP) 426 pg/ml. Antinuclear antibodies (ANA) were negative. Chest radiograph showed cardiomegaly and pulmonary reticulonodular pattern (Figure 1A). Chest … Address correspondence to Dr. H. Olschewski, Medical University of Graz, Department of Internal Medicine, Division of Pulmonology, A-8036 Graz, Auenbruggerplatz 20, Austria. E-mail: horst.olschewski{at}klinikum-graz.at.

The inflammatory cell landscape in the lungs of patients with idiopathic pulmonary arterial hypertension

Increasing evidence points towards an inflammatory component underlying pulmonary hypertension. However, the conclusive characterisation of multiple inflammatory cell populations in the lung is challenging due to the complexity of marker specificity and tissue inaccessibility. We used an unbiased computational flow cytometry approach to delineate the inflammatory landscape of idiopathic pulmonary arterial hypertension (IPAH) and healthy donor lungs. Donor and IPAH samples were discriminated clearly using principal component analysis to reduce the multidimensional data obtained from single-cell flow cytometry analysis. In IPAH lungs, the predominant CD45+ cell type switched from neutrophils to CD3+ T-cells, with increases in CD4+, CD8+ and γδT-cell subsets. Additionally, diversely activated classical myeloid-derived dendritic cells (CD14−HLA-DR+CD11c+CD1a+/−) and nonclassical plasmacytoid dendritic cells (pDCs; CD14−CD11c−CD123+HLA-DR+), together with mast cells and basophils, were more abundant in IPAH samples. We describe, for the first time, the presence and regulation of two cell types in IPAH, γδT-cells and pDCs, which link innate and adaptive immunity. With our high-throughput flow cytometry with multidimensional dataset analysis, we have revealed the interactive interplay between multiple inflammatory cells is a crucial part of their integrative network. The identification of γδT-cells and pDCs in this disease potentially provides a missing link between IPAH, autoimmunity and inflammation. Computational flow cytometry details the complex inflammatory cell landscape in patients with pulmonary hypertension http://ow.ly/rjFZ30g1tew

CD133+ cells in pulmonary arterial hypertension.

Circulating mononuclear cells may play an important role for the vascular remodelling in pulmonary arterial hypertension (PAH), but studies addressing multiple progenitor populations are rare and inconsistent. We used a comprehensive fluorescence-activated cell sorting analysis of circulating mononuclear cells in 20 PAH patients and 20 age- and sex-matched controls, and additionally analysed CD133+ cells in the lung tissue of five PAH transplant recipients and five healthy controls (donor lungs). PAH patients were characterised by increased numbers of circulating CD133+ cells and lymphopenia as compared with control. In PAH, CD133+ subpopulations positive for CD117 or CD45 were significantly increased, whereas CD133+CD309+, CD133+CXCR2+ and CD133+CD31+ cells were decreased. In CD133+ cells, SOX2, Nanog, Ki67 and CXCR4 were not detected, but Oct3/4 mRNA was present in both PAH and controls. In the lung tissue, CD133+ cells included three main populations: type 2 pneumocytes, monocytes and undifferentiated cells without significant differences between PAH and controls. In conclusion, circulating CD133+ progenitor cells are elevated in PAH and consist of phenotypically different subpopulations that may be up- or downregulated. This may explain the inconsistent results in the literature. CD133+ type 2 pneumocytes in the lung tissue are not associated with circulating CD133+ mononuclear cells. PAH patients are characterised by lymphopenia and increased numbers of CD133+ cells http://ow.ly/YNfQE

Mild Elevation of Pulmonary Arterial Pressure as a Predictor of Mortality

Rationale: Normal mean pulmonary arterial pressure (mPAP) is 14.0 ± 3.3 mm Hg (mean ± SD). The prognostic relevance of mildly elevated mPAP not fulfilling the definition of pulmonary hypertension (PH; mPAP ≥ 25 mm Hg) has not been prospectively evaluated in a real‐world setting. Objectives: To assess the association of resting mPAP with all‐cause mortality in a retrospective and a prospective cohort of patients with unexplained dyspnea and/or at risk of PH. Methods: Prognostic cutoffs were calculated by means of 1) classification and regression tree (CART) analysis without any preset thresholds, and 2) preset thresholds on the basis of literature data defining mPAP as lower‐normal (≤mean + 1 SD), upper‐normal (between mean + 1 SD and mean + 2 SD), borderline (between mean + 2 SD and 25 mm Hg), and manifest PH (≥25 mm Hg). We performed univariate and multivariate survival analysis adjusted for age and comorbidities. Measurements and Main Results: We enrolled 547 patients, of whom 137, 56, 64, and 290 presented with lower‐normal, upper‐normal, or borderline mPAP, and manifest PH, respectively. The CART analysis on mPAP discriminated three prognostic groups: mPAP less than 17 mm Hg, 17 to 26 mm Hg, and greater than 26 mm Hg, with significantly decreasing survival. The univariate analysis on the basis of preset thresholds showed that upper‐normal mPAP, borderline mPAP, and manifest PH were significantly associated with poor survival compared with lower‐normal mPAP. In the multivariate model, considering age and comorbidities, only borderline mPAP (hazard ratio, 2.37; 95% confidence interval, 1.14‐4.97; P = 0.022) and manifest PH (hazard ratio, 5.05; 95% confidence interval, 2.79‐9.12; P < 0.001) were significantly associated with poor survival. Conclusions: In patients at risk for PH and/or with unexplained dyspnea, CART analysis detects prognostic thresholds at a resting mPAP of 17 mm Hg and 26 mm Hg, and values between 20 mm Hg and 25 mm Hg represent an independent predictor of poor survival. Clinical trial registered with www.clinicaltrials.gov (NCT 01607502).

Use of ECG and Other Simple Non-Invasive Tools to Assess Pulmonary Hypertension.

Background There is a broad consensus that pulmonary hypertension (PH) is to be diagnosed by right heart catheterization (RHC) and that the most important non-invasive tool is echocardiography. However, the role of simple non-invasive tools in the work-up of PH is not clearly defined. We hypothesized that the use of simple non-invasive techniques may help to guide important decisions in the diagnostics of pulmonary hypertension. Objectives We aimed to develop an algorithm with the use of simple, non-invasive tools in order to identify patients with very high or very low likelihood of PH. Methods We retrospectively analyzed all consecutive patients undergoing RHC between 2005 and 2010 in our center and performed logistic regression of simple non-invasive parameters regarding detection and exclusion of PH and derived a two-step algorithm. In a prospective study we evaluated this algorithm between 2011 and 2013. Results The retrospective cohort consisted of n = 394 patients of which 49% presented with PH. Right axis deviation in the ECG was present in 90/394 patients and had a positive predictive value (PPV) of 93% for PH. The combination of non-right axis deviation, N-terminal pro brain natriuretic peptide (NT-proBNP)<333pg/ml, arterial oxygen saturation (SO2)≥95.5% and WHO functional class I-II was present in 69/394 patients and excluded PH with a negative predictive value (NPV) of 96%. The prospective study confirmed these results in a cohort of n = 168 patients (PPV:92%, NPV:97%). Taken together, simple non-invasive tools allowed a prediction regarding the presence or absence of PH in 42% of patients with suspected PH. Conclusion ECG, NT-proBNP, SO2 and WHO functional class may predict the presence or absence of PH in almost half of the patients with suspected PH, suggesting an important role for these variables in the work-up of patients at risk for PH. Clinical Trial Registration NCT01607502

Importance of kynurenine in pulmonary hypertension

The tryptophan metabolite kynurenine is significantly increased in pulmonary arterial hypertension (PAH) patients, and it is a potent vasodilator of systemic arteries. Our aim was to investigate the role of kynurenine in the pulmonary circulation. Serum tryptophan, kynurenine, and kynurenic acid levels were measured in 20 idiopathic PAH (IPAH) patients, 20 healthy controls, and 20 patients with chronic lung disease or metabolic syndrome without PH. Laser-dissected pulmonary arteries from IPAH and control lungs were tested for the expression of indoleamine-2, 3-dioxygenase (IDO), the rate-limiting enzyme for the conversion from tryptophan to kynurenine. Acute effects of kynurenine were tested in pulmonary vascular preparations, two different models of chronic pulmonary hypertension (PH), and in human pulmonary arterial smooth muscle cells (hPASMCs). In IPAH vs. control serum, kynurenine was significantly elevated (3.6 ± 0.2 vs. 2.6 ± 0.1 µM, P < 0.0001), and strongly associated with PH (area under the curve = 0.86), but kynurenine levels were not elevated in lung disease and metabolic syndrome. Among all investigated tryptophan metabolites, kynurenine displayed the strongest correlation with mean pulmonary arterial pressure (mPAP) (ρ: 0.770, P < 0.0001). Tryptophan was significantly decreased in IPAH lungs; however, IDO expression was not changed. In hPASMCs, kynurenine increased both cAMP and cGMP; in intrapulmonary arteries, it relaxed the preconstriction via NO/cGMP and cAMP pathways, and in two models of established PH, it acutely decreased the mPAP. Our data suggest that kynurenine elevation might be specifically associated with mPAP; kynurenine acts on hPASMCs in synergy with NO and exerts acute pulmonary vasodilatation in chronic PH models. Kynurenine might provide both a new biomarker and a new therapeutic option for PH.

Biomarkers for Pulmonary Vascular Remodeling in Systemic Sclerosis: A Pathophysiological Approach

Pulmonary arterial hypertension (PAH) is a severe complication of systemic sclerosis (SSc) associated with high morbidity and mortality. There are several biomarkers of SSc-PAH, reflecting endothelial physiology, inflammation, immune activation, extracellular matrix, metabolic changes, or cardiac involvement. Biomarkers associated with diagnosis, disease severity and progression have been identified, however, very few have been tested in a prospective setting. Some antinuclear antibodies such as nucleosome antibodies (NUC), anti-centromere antibodies (CENP-A/B) and anti-U3-ribonucleoprotein (anti-U3-RNP) are associated with PAH while anti-U1-ribonucleoprotein (anti-U1-RNP) is associated with a reduced PAH risk. Anti-endothelin receptor and angiotensin-1 receptor antibodies might be good markers of SSc-PAH and progression of pulmonary vasculopathy. Regarding the markers reflecting immune activation and inflammation, there are many inconsistent results. CXCL-4 was associated with SSc progression including PAH and lung fibrosis. Growth differentiation factor (GDF)-15 was associated with PAH and mortality but is not specific for SSc. Among the metabolites, kynurenine was identified as diagnostic marker for PAH, however, its pathologic role in the disease is unclear. Endostatin, an angiostatic factor, was associated with heart failure and poor prognosis. Established heart related markers, such as N-terminal fragment of A-type natriuretic peptide/brain natriuretic peptide (NT-proANP, NT-proBNP) or troponin I/T are elevated in SSc-PAH but are not specific for the right ventricle and may be increased to the same extent in left heart disease. Taken together, there is no universal specific biomarker for SSc-PAH, however, there is a pattern of markers that is strongly associated with a risk of vascular complications in SSc patients. Further comprehensive, multicenter and prospective studies are warranted to develop reliable algorithms for detection and prognosis of SSc-PAH.