MR-proADM Predicts Exercise Capacity and Survival Superior to Other Biomarkers in PH

Circulating biomarkers in pulmonary arterial hypertension: State-of-the-art review and future directions

Pulmonary arterial hypertension is a complex and heterogeneous condition, associated with a considerable diagnostic delay, diminished exercise capacity, and poor outcomes. In pulmonary arterial hypertension, biomarker research has become a subject of intense inquiry, and novel circulating biomarkers acknowledged in a multitude of mechanistic pathways are emerging. Beyond the widely used natriuretic peptides, novel biomarkers may provide deeper pathophysiological understanding, support clinical decision-making, and prompt the incorporation of precision medicine by enabling a more precise individual phenotyping. In this state-of-the-art review, the recent advances in circulating biomarkers in pulmonary arterial hypertension from a clinical perspective are discussed, with particular emphasis on the current state of knowledge, gaps in evidence, and future perspectives.

Clinical Potential of Adrenomedullin Signaling in the Cardiovascular System

Numerous clinical studies have revealed the utility of circulating AM (adrenomedullin) or MR-proAM (mid-regional proAM 45-92) as an effective prognostic and diagnostic biomarker for a variety of cardiovascular-related pathophysiologies. Thus, there is strong supporting evidence encouraging the exploration of the AM-CLR (calcitonin receptor-like receptor) signaling pathway as a therapeutic target. This is further bolstered because several drugs targeting the shared CGRP (calcitonin gene-related peptide)-CLR pathway are already Food and Drug Administration-approved and on the market for the treatment of migraine. In this review, we summarize the AM-CLR signaling pathway and its modulatory mechanisms and provide an overview of the current understanding of the physiological and pathological roles of AM-CLR signaling and the yet untapped potentials of AM as a biomarker or therapeutic target in cardiac and vascular diseases and provide an outlook on the recently emerged strategies that may provide further boost to the possible clinical applications of AM signaling.

Prognostic Value for Mortality of Plasma Bioactive Adrenomedullin in Patients with Pulmonary Arterial Hypertension: A Sub Analysis of the Biomarker Study in the COHARD-PH Registry

The adrenomedullin level increases in pulmonary arterial hypertension (PAH, and correlates with a high mortality rate. Its active form, bioactive adrenomedullin (bio-ADM), has been recently developed and has significant prognostic applications in acute clinical settings. Aside from idiopathic/hereditary PAH (I/H-PAH), atrial septal defects-associated pulmonary artery hypertension (ASD-PAH) is still prevalent in developing countries and associated with increased mortality. This study aimed to investigate the mortality-wise prognostic value of the plasma bio-ADM level by comparing subjects with ASD-PAH and I/H-PAH with ASD patients without pulmonary hypertension (PH) as a control group. This was a retrospective, observational cohort study. The subjects were Indonesian adult patients who were recruited from the Congenital Heart Disease and Pulmonary Hypertension (COHARD-PH) registry and divided into three groups: (1) ASD without PH (control group), (2) ASD-PAH and (3) I/H-PAH. During right-heart catheterization at the time of diagnosis, a plasma sample was taken and assayed for bio-ADM using a chemiluminescence immunoassay. Follow-up was performed as a part of the COHARD-PH registry protocol in order to evaluate the mortality rate. Among the 120 subjects enrolled: 20 turned out to have ASD without PH, 85 had ASD-PAH and 15 had I/H-PAH. Compared to the control group (5.15 (3.0-7.95 pg/mL)) and ASD-PAH group (7.30 (4.10-13.50 pg/mL)), bio-ADM levels were significantly higher in the I/H-PAH group (median (interquartile range (IQR)): 15.50 (7.50-24.10 pg/mL)). Moreover, plasma bio-ADM levels were significantly higher in subjects who died (n = 21, 17.5%) compared to those who survived (median (IQR): 11.70 (7.20-16.40 pg/mL) vs. 6.90 (4.10-10.20 pg/mL), p = 0.031). There was a tendency toward higher bio-ADM levels in those who died among the PAH subjects, in both ASD-PAH and I/H-PAH groups. In conclusion, the plasma bio-ADM level is elevated in subjects with PAH from both ASD-PAH and I/H-PAH origins, reaching the highest levels in subjects with the I/H-PAH form. A high bio-ADM level tended to be associated with a high mortality rate in all subjects with PAH, indicating a relevant prognostic value for this biomarker. In patients with I/H-PAH, monitoring bio-ADM could represent a valid tool for predicting outcomes, allowing more appropriate therapeutical choices.

Associations of Plasma Bioactive Adrenomedullin Levels with Cardiovascular Risk Factors in BRCA1/2 Mutation Carriers

Background Cardiovascular disease (CVD) is an important cause of morbidity and mortality in breast cancer survivors. Effective screening modalities to identify CVD risk are lacking in this population. Adrenomedullin (ADM) has been suggested as a biomarker for subclinical cardiac dysfunction in the general population. Levels of ADM have been proven to be responsive to lifestyle changes that lead to improved cardiovascular health. As BRCA1/2 mutation carriers are deemed to be at an increased risk for CVD, the aim of this study was to examine plasma ADM levels in a cohort of BRCA mutation carriers and to assess their association with cardiovascular risk factors.

Methods Plasma ADM concentrations were measured in 292 female BRCA1/2 mutation carriers with and without a history of breast cancer. Subjects were classified into high versus low ADM levels based on the median ADM level in the entire cohort (13.8 pg/mL). Logistic regression models were used to estimate the odds ratios (OR) of having elevated ADM levels by several cardiovascular risk factors.

Results Of all women (median age: 43 years), 57.5% had a previous diagnosis of breast cancer. The median time between diagnosis and study entry was three years (range: 0 – 32 years). Women presenting with metabolic syndrome had 22-fold increased odds of having elevated ADM levels (p < 0.001). Elevated ADM levels were associated with lower cardiorespiratory fitness (OR = 0.88, p < 0.001) and several parameters of obesity (p < 0.001). ADM levels were higher in women who have ever smoked (OR = 1.72, p = 0.02). ADM levels were not associated with a previous diagnosis of breast cancer (p = 0.28).

Conclusions This is the first study in BRCA mutation carriers that has linked circulating ADM levels to traditional cardiovascular risk factors. The long-term clinical implications of these findings are yet to be determined.

Comorbidity in idiopathic pulmonary fibrosis - what can biomarkers tell us?

Idiopathic pulmonary fibrosis (IPF) is characterized by progressive parenchymal scarring, leading to dyspnoea, respiratory failure and premature death. Although IPF is confined to the lungs, the importance of IPF comorbidities such as pulmonary hypertension and ischaemic heart disease, lung cancer, emphysema/chronic obstructive pulmonary disease, gastroesophageal reflux, sleep apnoea and depression has been increasingly recognized. These comorbidities may be associated with increased mortality and significant loss of quality of life, so their identification and management are vital. The development of good-quality biomarkers could lead to numerous gains in the management of these patients. Biomarkers can be used for the identification of predisposed individuals, early diagnosis, assessment of prognosis, selection of best treatment and assessment of response to treatment. However, the role of biomarkers for IPF comorbidities is still quite limited, and mostly based on evidence coming from populations without IPF. The future development of new biomarker studies could be informed by those that have been studied independently for each of these conditions. For now, clinicians should be mostly attentive to clinical manifestations of IPF comorbidities, and use validated diagnostic methods for diagnosis. As research on biomarkers of most common diseases continues, it is expected that useful biomarkers are developed for these diseases and then validated for IPF populations. The reviews of this paper are available via the supplemental material section.

Mid-regional pro-atrial natriuretic peptide and copeptin as indicators of disease severity and therapy response in CTEPH

BACKGROUND

Chronic thromboembolic pulmonary hypertension (CTEPH) leads to right heart failure. Pulmonary endarterectomy (PEA) or balloon pulmonary angioplasty (BPA) restore pulmonary haemodynamics and allow cardiac recovery. This study examined the relationship of copeptin and mid-regional pro-atrial natriuretic peptide (MR-proANP) levels to disease severity and therapy response.

METHODS

This observational cohort study included 125 patients (55 PEA/70 BPA) who underwent treatment and completed a 6-/12-month follow-up. Biomarkers, measured at baseline, prior to every BPA and at follow-up, were compared to 1) severe disease at baseline (right atrial pressure (RAP) ≥8 mmHg and cardiac index ≤2.4 L·min-1·m-2) and 2) optimal therapy response (no persistent pulmonary hypertension combined with a normalised RAP (mean PAP ≤25 mmHg, pulmonary vascular resistance (PVR) ≤3 WU and RAP ≤6 mmHg) or a reduction in mean PAP ≥25%, PVR ≥35% and RAP ≥25%).

RESULTS

Severely diseased patients had higher levels of MR-proANP (320 (246-527) pmol·L-1 versus 133 (82-215) pmol·L-1; p=0.001) and copeptin (12.7 (7.3-20.6) pmol·L-1 versus 6.8 (4.4-12.8) pmol·L-1; p=0.015) at baseline than the rest of the cohort. At baseline, MR-proANP (area under the curve (AUC) 0.91; cut-off value 227 pmol·L-1; OR 56, 95% CI 6.9-454.3) and copeptin (AUC 0.70; cut-off value 10.9 pmol·L-1; OR 1.5, 95% CI 1.2-1.9) identified severely diseased patients. After PEA/BPA, levels of MR-proANP (99 (58-145) pmol·L-1; p<0.001) and copeptin (6.3 (3.7-12.6) pmol·L-1; p=0.009) decreased and indicated optimal therapy response (MR-proANP <123 pmol·L-1 (AUC 0.70) and copeptin <10.1 pmol·L-1 (AUC 0.58)).

CONCLUSION

MR-proANP and copeptin levels are affected in CTEPH and decrease after therapy. MR-proANP identifies a severe disease status and optimal therapy response.

MR-proADM and MR-proANP levels in patients with acute pulmonary embolism

BACKGROUND

The aim of this study was to determine levels of Mid-regional Pro-adrenomedullin (MR-proADM) and Mid-regional Pro-atrial Natriuretic Peptide (MR-proANP) in patients with acute pulmonary embolism (PE), the relationship between these parameters and the risk classification in addition to determining the relationship between 1and 3month mortality.

METHODS

82 PE patients and 50 healthy control subjects were included in the study. Blood samples for Mr-proANP and Mr-proADM were obtained from the subjects prior to the treatment. Risk stratification was determined according to sPESI (Simplified Pulmonary Embolism Severity Index). Following these initial measurements, cases with PE were assessed in terms of all causative and PE related mortalities.

RESULTS

The mean serum Mr-proANP and Mr-proADM levels in acute PE patients were found to be statistically higher compared to the control group (p < 0.001, p < 0.01; respectively) and statistically significantly higher in high-risk patients than low-risk patients (p < 0.01, p < 0.05; respectively). No statistical difference was determined in high-risk patients in case of sPESI compared to low-risk patients while hospital mortality rates were higher. It was determined that the hospital mortality rate in cases with Mr-proANP ≥ 123.30 pmol/L and the total 3-month mortality rate in cases with Mr-proADM ≥ 152.2 pg/mL showed a statistically significant increase.

CONCLUSIONS

This study showed that Mr-proANP and MRproADM may be an important biochemical marker for determining high-risk cases and predicting the mortality in PE patients and we believe that these results should be supported by further and extensive studies.

Plasma adrenomedullin peptides and precursor levels in pulmonary arterial hypertension disease severity and risk stratification

Adrenomedullin is a potent vasodilatory peptide, linked to pulmonary arterial hypertension pathology. Proximity extension assays were utilized to study plasma biomarkers related to vasoregulation, with focus on adrenomedullin peptides and precursor levels, collectively referred to as ADM. ADM was measured in 48 treatment-naïve pulmonary arterial hypertension patients at diagnosis, and in 31 of them at an early treatment follow-up. Plasma ADM was additionally assessed in patients with chronic thromboembolic pulmonary hypertension (n = 20) and pulmonary hypertension due to heart failure with preserved (HFpEF_(PH)) (n = 33) or reduced (HFrEF_(PH)) (n = 36) ejection fraction, as well as healthy controls (n = 16). ADM was studied in relation to pulmonary arterial hypertension hemodynamics, risk assessment, prognosis, treatment response, and differentiation. Plasma ADM levels in pulmonary arterial hypertension patients at diagnosis were higher than in healthy controls (p < 0.001), similar as in chronic thromboembolic pulmonary hypertension patients (p = ns), but lower compared to HFpEF_(PH) (p < 0.03) and HFrEF_(PH) (p < 0.001). In pulmonary arterial hypertension, specifically, plasma ADM at diagnosis correlated mainly to mean right atrial pressure (r = 0.73, p < 0.001), N-terminal prohormone of brain natriuretic peptide (r = 0.75, p < 0.001), six-minute walking distance (r = -0.57, p < 0.001), and venous oxygen saturation (r = -0.57, p < 0.001). ADM also correlated to the ECS/ERS- (r = 0.74, p < 0.001) and REVEAL risk scores (r = 0.54, p < 0.001) at pulmonary arterial hypertension diagnosis. Plasma ADM in pulmonary arterial hypertension patients was unaltered at early treatment follow-up compared to baseline (p = ns). Pulmonary arterial hypertension patients with supra-median ADM at diagnosis showed worse overall survival than those with infra-median levels (median survival 34 versus 66 months, p = 0.0077). In conclusion, the present results suggest that baseline plasma ADM levels mirror disease severity, correlating to both ECS/ERS- and the REVEAL risk scores.

[Novel Biomarkers of Pulmonary Hypertension]

Pulmonary hypertension (PH) is a clinical syndrome characterized by a progressive increase in pulmonary vascular resistance (PVR), which leads to remodeling of the right ventricle (RV), right heart failure and premature death of patients. Early diagnosis and monitoring of disease progression are crucial for making decisions about the necessary therapy. The gold standard for the diagnosis of pulmonary hypertension is the right heart catheterization. The estimation of systolic pressure in pulmonary artery by means of transthoracic echocardiography is also used for monitoring the course of the disease. At present, there is still a need for non-invasive biomarkers that reflect pathological changes in pulmonary arterial vessels and allow diagnosing of PH. Our review outlines the new data about some biomarkers potentially useful for diagnosis and prognostication of PH. These biomarkers (mid-regional pro-adrenomedullin, carboxyterminal pro-endothelin-1, copeptin, asymmetric dimethylarginine, growth differentiation factor 15, and others) are classified based on their relationship to endothelial cell dysfunction, inflammation, epigenetics, cardiac function, oxidative stress, extracellular matrix. The determination of biomarkers that are of diagnostic value for predicting the severity, progression of PH and response to therapy, in a simple blood test or condensate of exhaled air, can significantly reduce treatment costs and improve PH management.

Study on the clinical efficacy of specific phosphodiesterase inhibitor in patients with pulmonary hypertension due to left heart disease

Pulmonary hypertension due to left heart disease (PH-LHD) is caused by left ventricular (LV) systolic and/or diastolic dysfunction and left heart valve disease. LV diseases lead to left ventricular filling pressure increases, pulmonary venous obstruction and pulmonary venous pressure increases, and thus to secondary PH. Exercise tolerance is lower and fatality rates are higher in patients with PH-LHD than those in subjects with normal pulmonary arterial pressure. In spite of the progress in the study of the mechanisms of PH-LHD in recent years, no specific treatment is currently available. The efficacy and safety of targeted therapies for pulmonary arterial hypertension remain to be fully established. In the present study, PH-LHD patients were treated with milrinone injection. It was concluded that milrinone significantly reduces pulmonary artery systolic pressure (PASP) in patients with PH-LHD, and significantly improves the cardiac structure, cardiac function and biochemical indexes. PASP was significantly correlated with the left atrial diameter, LV end diastolic diameter, LV ejection fraction, tricuspid annular plane systolic excursion, right ventricular fractional area change, N-terminal pro-B-type natriuretic peptide and hypersensitive C-reactive protein.

Novel biomarkers for pulmonary arterial hypertension

Pulmonary arterial hypertension is a deadly disease characterized by elevated pulmonary arterial pressures leading to right ventricular hypertrophy and failure. The confirmatory gold standard test is the invasive right heart catheterization. The disease course is monitored by pulmonary artery systolic pressure measurement via transthoracic echocardiography. A simple non-invasive test to frequently monitor the patients is much needed. Search for a novel biomarker that can be detected by a simple test is ongoing and many different options are being studied. Here we review some of the new and unique pre-clinical options for potential pulmonary hypertension biomarkers. These biomarkers can be broadly categorized based on their association with endothelial cell dysfunction, inflammation, epigenetics, cardiac function, oxidative stress, metabolism,extracellular matrix, and volatile compounds in exhaled breath condensate. A biomarker that can be detected in blood, urine or breath condensate and correlates with disease severity, progression and response to therapy may result in significant cost reduction and improved patient outcomes.

Role of Biomarkers in the Diagnosis, Risk Assessment, and Management of Pulmonary Hypertension

Pulmonary hypertension is a severe and debilitating disease with no definite cure, and the domain of targeted therapies is a promising field for better management of this severe condition. The disease comprises pulmonary arterial remodeling, hypoxia, endothelial dysfunction, and inflammation, with subsequent organ damage including right heart and liver dysfunction. Biomarkers have a valuable role at different levels of the disease, from diagnosis to risk assessment and management, in order to decrease the burden of the disease in terms of both morbidity and mortality.