A review of the biological properties and clinical implications of adrenomedullin and proadrenomedullin N-terminal 20 peptide (PAMP), hypotensive and vasodilating peptides

New insight into prurigo nodularis: Proadrenomedullin N-terminal 20 peptide mediates mouse mast cell activation via Mrgprb2

BACKGROUND

Prurigo nodularis (PN) is a chronic inflammatory skin disorder that is characterized by extremely itchy nodules. Proadrenomedullin N-terminal 20 (PAMP) activates mast cell degranulation via Mas-related G protein-coupled receptor X2 (MRGPRX2), which is associated with pruritus in allergic contact dermatitis. However, the mechanisms underlying the action of PAMP and MRGPRX2 in PN remain unclear.

OBJECTIVE

To determine the role of PAMP-induced mast cell activation via MRGPRX2 (mouse homologous Mrgprb2) in PN.

METHODS

The expression of PAMP and the number of MRGPRX2-expressing mast cells in the skin biopsies of patients with PN, atopic dermatitis (AD), and healthy participants were analyzed using immunohistochemistry and immunofluorescence, respectively. The biphasic response of PAMP9-20 mediated by Mrgprb2 in mouse peritoneal mast cells (PMC) was validated in vitro using qRT-PCR, ELISA, flow cytometry, and siRNA techniques.

RESULTS

PAMP expression and the number of MRGPRX2+ mast cells in lesional PN skin, but not in AD, were elevated compared to healthy skin. PAMP9-20 mediates the immediate and delayed phase responses of PMC, such as degranulation, histamine and β-hexosaminidase release, and secretion of inflammatory factors such as CCL2, TNF-α, and GM-CSF. These effects were inhibited when Mrgprb2 expression was silenced. Silencing Mrgprb2 did not affect the biphasic response of PMC that was induced by IgE-FcεRI activation.

CONCLUSIONS

The results show that PAMP mediates mouse mast cell activation via Mrgprb2, which may be involved in the pathogenesis of PN. The PAMP/ Mrgprb2 pathway, independent of classical IgE signaling, could be developed as a candidate drug target for treating PN.

A Review of Adrenomedullin in Pediatric Patients: A Useful Biomarker

Adrenomedullin has several properties. It acts as a potent vasodilator, has natriuretic effects, and reduces endothelial permeability. It also plays a role in initiating the early hyperdynamic phase of sepsis. Since its discovery, many articles have been published studying the uses and benefits of this biomarker. The aim of this review is to determine the usefulness of adrenomedullin in pediatric patients. Relevant studies covering adrenomedullin in pediatrics (<18 years) and published up until August 2021 were identified through a search of MEDLINE, PubMed, Embase, Web of Science, Scopus, and Cochrane. Seventy studies were included in the present review, most of them with a low level of evidence (IV to VI). Research on adrenomedullin has primarily been related to infection and the cardiovascular field. The performance of adrenomedullin to quantify infection in children seems satisfactory, especially in sepsis. In congenital heart disease, this biomarker seems to be a useful indicator before, during, and after cardiopulmonary bypass. Adrenomedullin seems to be useful in the pediatric population for a large variety of pathologies, especially regarding infection and cardiovascular conditions. However, it should be used in combination with other biomarkers and clinical or analytical variables, rather than as a single tool.

Plasma Adrenomedullin, Allelic Variations in the ADM Gene, and Risk for Lower-Limb Amputation in People With Type 2 Diabetes

OBJECTIVE

Patients with diabetes have an increased risk for lower-limb amputation (LLA), but biomarkers to assess risk of LLA are lacking. Adrenomedullin (ADM) is a vasodilator peptide that also plays a role in fluid and electrolyte homeostasis in the kidney, increasing natriuresis and diuresis. ADM was shown to be associated with cardiovascular and renal events in diabetes, but it was not investigated in terms of LLA risk. We investigated the hypothesis that ADM is associated with LLA in people with type 2 diabetes.

RESEARCH DESIGN AND METHODS

We studied 4,375 participants in the DIABHYCAR and SURDIAGENE cohorts (men, 68%; mean 66 years of age; mean duration of diabetes 12 years; and median follow-up 5.3 years). Plasma midregional proadrenomedullin (MR-proADM; a surrogate for ADM) was measured by immunofluorescence. Five single nucleotide polymorphisms (SNPs) in the ADM gene region were genotyped.

RESULTS

LLA requirement during follow-up by increasing tertiles of plasma MR-proADM distribution was 1.0% (tertile 1 [T1]), 2.3% (T2), and 4.4% (T3) (P < 0.0001). In Cox multivariate analysis, the adjusted hazard ratio (95% CI) for LLA was 4.40 (2.30-8.88) (P < 0.0001) for T3 versus T1. Moreover, MR-proADM significantly improved indices for risk stratification of LLA. Four SNPs were associated with plasma MR-proADM concentration at baseline and with LLA during follow-up. Alleles associated with higher MR-proADM were associated with increased LLA risk.

CONCLUSIONS

We observed associations of plasma MR-proADM with LLA and of ADM SNPs with plasma MR-proADM and with LLA in people with type 2 diabetes. This pattern of Mendelian randomization supports the causality of the association of ADM with LLA.

Plasma Levels of Mid-Regional Proadrenomedullin Accurately Identify H1N1pdm09 Influenza Virus Patients with Risk of Intensive Care Admission and Mortality in the Emergency Department

Early identification of severe viral pneumonia in influenza virus A (H1N1pdm09) patients is extremely important for prompt admission to the ICU. The objective is to evaluate the usefulness of MR-proadrenomedullin (MR-proADM) compared to C reactive protein (CRP), procalcitonin (PCT), and ferritin in the prognosis of influenza A pneumonia. This prospective, observational, multicenter study included one hundred thirteen patients with confirmed influenza virus A (H1N1pdm09) admitted to an Emergency Department and ICUs of six hospitals in Spain. Measurements and Main Results: one-hundred thirteen patients with confirmed influenza virus A (H1N1pdm09) were enrolled. Seventy-five subjects (mortality 29.3%) with severe pneumonia caused by influenza A H1N1pdm09 virus (H1N1vIPN) were compared with 38 controls (CG).The median MR-proADM levels at hospital admission were 1.2 nmol/L (IQR (0.8–2.6) vs. 0.5 nmol/L (IQR 0.2–0.9) in the CG (p = 0.01), and PCT levels were 0.43 μg/L (IQR 0.2–1.2) in the H1N1vIPN group and 0.1 μg/L (IQR 0.1–0.2) in the CG (p < 0.01). CRP levels at admission were 15.5 mg/dL(IQR 9.2–24.9) in H1N1vIPN and 8.6 mg/dL(IQR 3–17.3) in the CG (p < 0.01). Ferritin levels at admission were 558.1 ng/mL(IQR 180–1880) in H1N1vIPN and 167.7 ng/mL(IQR 34.8–292.9) in the CG (p < 0.01). A breakpoint for hospital admission of MR-proADM of 1.1 nmol/L showed a sensitivity of 55% and a specificity of 90% (AUC-ROC0.822). Non-survivors showed higher MR-proADM levels: median of 2.5 nmol/L vs. 0.9 nmol/L among survivors (p < 0.01). PCT, CRP, and ferritin levels also showed significant differences in predicting mortality. The MR-proADM AUC-ROC for mortality was 0.853 (p < 0.01). In a Cox proportional hazards model, MR-proADM levels > 1.2 nmol/L at hospital admission were significant predictive factors for ICU and 90-day mortality (HR: 1.3). Conclusions: the initial MR-proADM, ferritin, CRP, and PCT levels effectively determine adverse outcomes and risk of ICU admission and mortality in patients with influenza virus pneumonia. MR-proADM has the highest potency for survival prediction.

Calcitonin Gene Related Peptide, Adrenomedullin, and Adrenomedullin 2 Function in Uterine Artery During Human Pregnancy

RATIONALE

Calcitonin gene-related peptide (CGRP) and its family members adrenomedullin (ADM) and adrenomedullin 2 (ADM2; also known as intermedin) support vascular adaptions in rat pregnancy.

OBJECTIVE

This study aimed to assess the relaxation response of uterine artery (UA) for CGRP, ADM, and ADM2 in nonpregnant and pregnant women and identify the involved mechanisms.

FINDINGS

(1) Segments of UA from nonpregnant women that were precontracted with U46619 (1μM) in vitro are insensitive to the hypotensive effects of CGRP, ADM, and ADM2; (2) CGRP, ADM, and ADM2 (0.1-100nM) dose dependently relax UA segments from pregnant women with efficacy for CGRP > ADM = ADM2; (3) the relaxation responses to CGRP, ADM, and ADM2 are differentially affected by the inhibitors of nitric oxide (NO) synthase (L-NAME), adenylyl cyclase (SQ22536), apamin, and charybdotoxin; (4) UA smooth muscle cells (UASMC) express mRNA for calcitonin receptor-like receptor (CRLR) and receptor activity modifying protein (RAMP)1 and RAMP2 but not RAMP3; (5) receptor heterodimer comprising CRLR/RAMP1 and CRLR/RAMP2 but not CRLR/RAMP3 is present in UA; (6) soluble fms-like tyrosine kinase (sFLT-1) and TNF-α treatment decrease the expression of RAMP1 mRNA (P < 0.05) in UASMC; and (7) sFLT-1 treatment impairs the association of CRLR with all 3 peptides while TNF-α inhibits the interaction of CGRP but not ADM or ADM2 with CRLR in UASMC (P < 0.05).

CONCLUSIONS

Relaxation sensitivity of UA for CGRP, ADM, and ADM2 is increased during pregnancy via peptide-specific involvement of NO system and endothelium-derived hyperpolarizing factors; vascular disruptors such as sFLT-1 and TNFα adversely impact their receptor system in UASMC.

Proadrenomedullin N-Terminal 20 Peptides (PAMPs) Are Agonists of the Chemokine Scavenger Receptor ACKR3/CXCR7

Adrenomedullin (ADM) and proadrenomedullin N-terminal 20 peptide (PAMP) are two peptides with vasodilative, bronchodilative, and angiogenic properties, originating from a common precursor, proADM. Previous studies proposed that the atypical chemokine receptor ACKR3 might act as a low-affinity scavenger for ADM, regulating its availability for its cognate receptor calcitonin receptor-like receptor (CLR) in complex with a receptor activity modifying protein (RAMP). In this study, we compared the activation of ACKR3 by ADM and PAMP, as well as other related members of the calcitonin gene-related peptide (CGRP) family. Irrespective of the presence of RAMPs, ADM was the only member of the CGRP family to show moderate activity toward ACKR3. Remarkably, PAMP, and especially further processed PAMP-12, had a stronger potency toward ACKR3 than ADM. Importantly, PAMP-12 induced β-arrestin recruitment and was efficiently internalized by ACKR3 without inducing G protein or ERK signaling in vitro. Our results further extend the panel of endogenous ACKR3 ligands and broaden ACKR3 functions to a regulator of PAMP-12 availability for its primary receptor Mas-related G-protein-coupled receptor member X2 (MrgX2).

Novel biomarkers in cardiovascular surgery

Cardiovascular disease includes health problems related to the heart, arteries and veins and is a significant healthcare problem worldwide. Cardiovascular disease may be acute or chronic and relapses are frequent. Biomarkers involved in this field may help clinicians and surgeons in diagnosis and adequate decision making. Relevant articles searched in the following databases Medline, Scopus, ScienceDirect, were retrieved and analysed. Several biomarkers have been identified and we analyzed those of most importance from a clinical and surgical point of view. Biomarkers can better identify high-risk individuals, facilitate follow-up process, provide information regarding prognosis and better tailor the most appropriate surgical treatment.

Targeting Adrenomedullin in Oncology: A Feasible Strategy With Potential as Much More Than an Alternative Anti-Angiogenic Therapy

The development, maintenance and metastasis of solid tumors are highly dependent on the formation of blood and lymphatic vessels from pre-existing ones through a series of processes that are respectively known as angiogenesis and lymphangiogenesis. Both are mediated by specific growth-stimulating molecules, such as the vascular endothelial growth factor (VEGF) and adrenomedullin (AM), secreted by diverse cell types which involve not only the cancerogenic ones, but also those constituting the tumor stroma (i.e., macrophages, pericytes, fibroblasts, and endothelial cells). In this sense, anti-angiogenic therapy represents a clinically-validated strategy in oncology. Current therapeutic approaches are mainly based on VEGF-targeting agents, which, unfortunately, are usually limited by toxicity and/or tumor-acquired resistance. AM is a ubiquitous peptide hormone mainly secreted in the endothelium with an important involvement in blood vessel development and cardiovascular homeostasis. In this review, we will introduce the state-of-the-art in terms of AM physiology, while putting a special focus on its pro-tumorigenic role, and discuss its potential as a therapeutic target in oncology. A large amount of research has evidenced AM overexpression in a vast majority of solid tumors and a correlation between AM levels and disease stage, progression and/or vascular density has been observed. The analysis presented here indicates that the involvement of AM in the pathogenesis of cancer arises from: 1) direct promotion of cell proliferation and survival; 2) increased vascularization and the subsequent supply of nutrients and oxygen to the tumor; 3) and/or alteration of the cell phenotype into a more aggressive one. Furthermore, we have performed a deep scrutiny of the pathophysiological prominence of each of the AM receptors (AM₁ and AM₂) in different cancers, highlighting their differential locations and functions, as well as regulatory mechanisms. From the therapeutic point of view, we summarize here an exhaustive series of preclinical studies showing a reduction of tumor angiogenesis, metastasis and growth following treatment with AM-neutralizing antibodies, AM receptor antagonists, or AM receptor interference. Anti-AM therapy is a promising strategy to be explored in oncology, not only as an anti-angiogenic alternative in the context of acquired resistance to VEGF treatment, but also as a potential anti-metastatic approach.

The effect of swimming training on adrenomedullin levels, oxidative stress variables, and gastrocnemius muscle contractile properties in hypertensive rats

Introduction/Aim: Regular exercise may have beneficial effects on high blood-pressure, as shown in different types of experimental hypertension models in rats. The present study aims to investigate the effects of 6-week swimming training on blood pressure, oxidative stress variables of selected tissues, serum adrenomedullin (ADM) levels, and in situ muscle contraction in rats with hypertension induced by Nω-nitro-L-arginine methyl ester hydrochloride (L-NAME), an inhibitor of endothelial nitric oxide synthases (eNOs). Materials and Methods: Twenty-six male Sprague Dawley, 8 weeks of age, rats were randomly divided into four groups: (I) normotensive (C), (II) normotensive + exercise (E), (III) hypertensive (L), and (IV) hypertensive + exercise (LE). Hypertension was induced by the oral administration of L-NAME (60 mg/kg) for 6 weeks. Exercise was performed 5 times (1-h each) per week for 6 weeks. At the end of the experiment, blood and tissue samples (the gastrocnemius muscle, heart, kidney, and thoracic aorta) were collected following contractile properties of the gastrocnemius muscle in situ weredetermined. In the collected tissues, oxidative stress (e.g., lipid oxidation and antioxidant enzyme activity) and serum ADM levels were measured. 6-week L-NAME administration per se (Group L) led to a significant increase in systolic and diastolic blood pressure compared to other groups.  Results: Importantly, 6-week exercise caused a protective effect of high blood pressure in the rats received L-NAME (Group LE). The level of ADM was lower in the rats received L-NAME than that of the control group. L-NAME increased lipid peroxidation in the thoracic aorta and decreased superoxide dismutase in the heart, kidney and muscle, and decreased catalase and glutathione in the heart. However, the exercise intervention did not have protective effect on the L-NAME-mediated oxidative damage in the collected tissues.  Conclusion: In conclusion, 6-week exercise intervention rescued rats from high blood pressure, but did not have ameliorative effect on the decreased ADM levels.

The value of biomarker-guided antibiotic therapy

INTRODUCTION

There is an increasing interest to individualize patient management and decisions regarding antibiotic treatment. Biomarkers may provide relevant information for this purpose.

AREAS COVERED

Despite a growing number of clinical trials investigating several biomarkers, there remain open questions regarding the best type of biomarker, timing or frequency of testing, and optimal cutoffs among others. The most promising results in regard to diagnosis of bacterial infection and therapy monitoring are found for procalcitonin (PCT), although some recent trials were not able to validate the promising earlier findings. Furthermore, less specific markers like C-reactive protein (CRP) and new prognostic biomarkers such as proadrenomedullin (MR-proADM) may improve the prognostic assessment of patients and proteomics may help shorten time to microbiological results. The aim of this review is to summarize the current concept of biomarker-guided management and provide an outlook of promising ongoing investigations.

EXPERT OPINION

'Antibiotic stewardship' is complex and needs more than just the measurement of one single biomarker. However, when integrated into the context of a thorough clinical examination, standard blood parameters and a well done risk stratification by clinical scores such as the SOFA-score, biomarkers have great potential to improve the diagnostic and prognostic assessment of patients.

How biomarkers can improve pneumonia diagnosis and prognosis: procalcitonin and mid-regional-pro-adrenomedullin

Aim: The diagnostic and prognostic role of procalcitonin (PCT) and mid-regional-pro-adrenomedullin (MR-proADM) were investigated in patients with pneumonia. Material & methods: A total of 168 and 77 patients with pneumonia enrolled in two different hospital settings, an internal medicine unit and an emergency unit were included in the study. PCT and MR-proADM plasma concentrations and pneumonia severity index score were measured. Median values were compared by Mann–Whitney’s test. Receiver operating characteristic analysis and rank correlation were used to define the diagnostic and prognostic accuracy. Results: PCT confirmed the diagnostic role at values 0.08–0.10 ng/ml and MR-proADM the prognostic role for severe pneumonia. Significant correlation (p < 0.0001) between MR-proADM and pneumonia severity index score indicated expression of pneumonia severity. Conclusion: This combination of biomarkers presents a high positive predictive value in pneumonia diagnosis and prognosis.

Postoperatively increased bioactive adrenomedullin is related to adverse outcome after complex aortic surgery

Summary: Background: Open and endovascular thoracoabdominal aortic aneurysm repair is related to major complications and increased mortality rates. Up to now, specific biomarkers for adverse outcome are scarce, although routine usage of such biomarkers could enable an earlier and more appropriate treatment of complications during the postoperative course after complex aortic aneurysm repair. Patients and methods: In a prospective single-center study including 33 patients (48.5 % women, mean age 63.0 ± 16.2 years) undergoing elective complex open and endovascular aortic aneurysm repair, bioactive adrenomedullin (bio-ADM) was measured for 72 h perioperatively and an association with clinical endpoints, namely cardiogenic shock, death and the combined endpoint of the two aforementioned parameters was assessed. Furthermore, the association between bio-ADM and baseline characteristics and perioperative details including sepsis biomarkers score were assessed. Results: 51.5 % (n = 17) of patients developed postoperative acute kidney injury, 21.2 % (n = 7) pneumonia and 18.2 % (n = 6) sepsis. Cardiogenic shock was observed in 12.1 % (n = 4) patients. The in-hospital mortality rate was 18.2 % (n = 6), and 24.2 % (n = 8) of patients developed cardiogenic shock and/or died in hospital. A significant correlation of bio-ADM concentrations from all available time points was observed with leukocytes (r = 0.37, P < 0.0001), C-reactive protein (r = 0.56, P < 0.001) and serum creatinine levels (r = 0.52, P < 0.001). Increased bio-ADM at 12 h, 24 h, 48 h and 72 h after admission to ICU was associated with both, in-hospital death and cardiogenic shock, with an area under the curve for the combined endpoint of 0.598, 0.720, 0.880 and 0.967. Bio-ADM concentrations at 48 h and 72 h after admission to ICU were predictive for in-hospital death and cardiogenic shock (both P < 0.01). Conclusions: Bio-ADM may serve as postoperative biomarker for cardiogenic shock and death after complex open and endovascular aortic aneurysm repair, potentially enabling an earlier and by that more adequate treatment of adverse outcome after major surgery.

Gender differences in community-acquired pneumonia

INTRODUCTION

Community-acquired pneumonia (CAP) is the most common type of lower respiratory tract infection and a major cause of morbidity and mortality in adults worldwide. Sex and gender play an active role in the incidence and outcomes of major infectious diseases, including CAP.

EVIDENCE ACQUISITION

We searched the following electronic databases from January 2001 to December 2018: MEDLINE, EMBASE, CINHAIL, CENTRAL (Cochrane Central register of Controlled Trials), DARE (Database of Abstracts of Reviews of Effectiveness), Cochrane Database of Systematic Reviews and ACP Journal Club database.

EVIDENCE SYNTHESIS

Several studies have reported higher male susceptibility to pulmonary infections and higher risk of death due to sepsis. Biological differences (e.g. hormonal cycles and cellular immune-mediated responses) together with cultural, behavioral and socio-economic differences are important determinants of the course and outcome of CAP. However, gender-related bias in the provision of care and use of hospital resources has been reported among women, resulting in delayed hospital admission and consequently necessary care.

CONCLUSIONS

CAP is more severe in males than in females, leading to higher mortality in males, especially in older age. To identify gender differences in CAP can guide patient's prognostication and management.

The ventral peptidergic system of the adult ascidian Ciona robusta (Ciona intestinalis Type A) insights from a transgenic animal model

Ascidians are the sister group of vertebrates and occupy a critical position in explorations of the evolution of the endocrine and nervous systems of chordates. Here, we describe the complete ventral peptidergic system in adult transgenic Ciona robusta (Ciona intestinalis Type A) which expresses the Kaede reporter gene driven by the prohormone convertase 2 (PC2) gene promoter. Numerous PC2 promoter-driven fluorescent (Kaede-positive) non-neural cells were distributed in the blood sinus located at the anterior end of the pharynx, suggesting the acquisition of a peptidergic circulatory system in Ciona. Kaede-positive ciliated columnar cells, rounded cells, and tall ciliated cells were observed in the alimentary organs, including the endostyle, pharynx, esophagus, stomach, and intestine, suggesting that digestive functions are regulated by multiple peptidergic systems. In the heart, Kaede-positive neurons were located in the ring-shaped plexus at both ends of the myocardium. Nerve fiber-like tracts ran along the raphe and appeared to be connected with the plexuses. Such unique structures suggest a role for the peptidergic system in cardiac function. Collectively, the present anatomic analysis revealed the major framework of the ventral peptidergic system of adult Ciona, which could facilitate investigations of peptidergic regulation of the pharynx, endostyle, alimentary tissues, and heart.

Mid-regional pro-adrenomedullin predicts poor outcome in non-selected patients admitted to an intensive care unit

Background Mortality risk and outcome in critically ill patients can be predicted by scoring systems, such as APACHE and SAPS. The identification of prognostic biomarkers, simple to measure upon admission to an intensive care unit (ICU) is an open issue. The aim of this observational study was to assess the prognostic value of plasma mid-regional pro-adrenomedullin (MR-proADM) at ICU admission in non-selected patients in comparison to Acute Physiology and Chronic Health Evaluation II (APACHEII) and Simplified Acute Physiology Score II (SAPSII) scores. Methods APACHEII and SAPSII scores were calculated after 24 h from ICU admission. Plasma MR-proADM levels were measured by TRACE-Kryptor on admission (T0) and after 24 h (T24). The primary endpoint was intra-hospital mortality; secondary endpoint was length of stay (LOS). Results One hundred and twenty-six consecutive non-selected patients admitted to an ICU were enrolled. Plasma MR-proADM levels were correlated with LOS (r=0.28; p=0.0014 at T0; r=0.26; p=0.005 at T24). Multivariate analysis showed that T0 MR-proADM was a significant predictor of mortality (odds ratio [OR]: 1.27; 95% confidence interval [95%CI]: 1.03-1.55; p=0.022). Receiver operating characteristic curves analysis revealed that MR-proADM on ICU admission identified non-survivors with high accuracy, not inferior to the one of APACHEII and SAPSII scores (area under the curve [AUC]: 0.71; 95%CI: 0.62-0.78; p=0.0002 for MR-proADM; AUC: 0.71; 95%CI: 0.62-0.79; p<0.0001 for APACHEII; AUC: 0.8; 95%CI: 0.71-0.87; p<0.0001 for SAPSII). Conclusions Our findings point out a role of MR-proADM as a prognostic tool in non-selected patients in ICUs being a reliable predictor of mortality and LOS and support its use on admission to an ICU to help the management of critically ill patients.

Galanin and Adrenomedullin Plasma Responses During Artificial Gravity on a Human Short-Arm Centrifuge

Galanin and adrenomedullin plasma responses to head-up tilt and lower body negative pressure have been studied previously. However, to what extent short-arm human centrifugation (SAHC) affects these responses is not known. In this study, we assessed how the application of variable gradients of accelerations (ΔGz ) via shifting of the rotation axis during centrifugation affects selected hormonal responses. Specifically, we tested the hypothesis, that cardiovascular modulating hormones such as galanin and adrenomedullin will be higher in non-finishers (participants in whom at least one of the pre-defined criteria for presyncope was fulfilled) when compared to finishers (participants who completed the entire protocol in both sessions) during SAHC exposure. Twenty healthy subjects (10 women and 10 men) were exposed to two g-levels [1 Gz and 2.4 Gz at the feet (Gz_Feet)] in two positions (axis of rotation placed above the head and axis of rotation placed at the heart level). Elevated baseline levels of galanin appeared to predict orthostatic tolerance (p = 0.054) and seemed to support good orthostatic tolerance during 1 Gz_Feet SAHC (p = 0.034). In finishers, 2.4 Gz_Feet SAHC was associated with increased galanin levels after centrifugation (p = 0.007). For adrenomedullin, the hypothesized increases were observed after centrifugation at 1 Gz_Feet (p = 0.031), but not at 2.4 Gz_Feet, suggesting that other central mechanisms than local distribution of adrenomedullin predominate when coping with central hypovolemia induced by SAHC (p > 0.14). In conclusion, baseline galanin levels could potentially be used to predict development of presyncope in subjects. Furthermore, galanin levels increase during elevated levels of central hypovolemia and galanin responses appear to be important for coping with such challenges. Adrenomedullin release depends on degree of central hypovolemia induced fluid shifts and a subject's ability to cope with such challenges. Our results suggest that the gradient of acceleration (ΔGz ) is an innovative approach to quantify the grade of central hypovolemia and to assess neurohormonal responses in those that can tolerate (finishers) or not tolerate (non-finishers) artificial gravity (AG). As AG is being considered as a preventing tool for spaceflight induced deconditioning in future missions, understanding effects of AG on hormonal responses in subjects who develop presyncope is important.

Plasma levels of mid-regional pro-adrenomedullin in sepsis are associated with risk of death

BACKGROUND

Identifying Intensive Care Unit (ICU) patients with sepsis and predicting the risk of death are unmet clinical needs.

METHODS

Prospective observational single-center study of 120 consecutive ICU patients with suspected severe sepsis at Jerez Hospital. Epidemiological, clinical, laboratory data and MR-proADM, Procalcitonin (PCT) and C-reactive protein (CRP) levels were recorded at ICU admission and follow-up.

RESULTS

At ICU discharge, 104 patients were diagnosed with severe sepsis and 39 died. Plasma MR-proADM was highly indicative of sepsis: 4.05 nmol/L vs. of 0.309 nmol/L (P<0.001), with area under the ROC curve (AUC-ROC) was 0.947. At 48 hours following admission, the median MR-proADM levels in surviving sepsis patients fell to 1.65 nmol/L but remained higher in the non-survivors (2.475 nmol/L) (P=0.04). On day 5 the levels fell to 1.36 nmol/L in surviving sepsis patients vs. 3.42 nmol/L in the non-survivors (P<0.001). On day 5 the survivors showed greater MR-proADM clearance (62.7% vs. 21.2%). The AUC-ROC on day 5 was 0.825, PCT 0.725 and CRP 0.700. The AUC-ROC to MR-proADM clearance on day 5 was 0.734. In a multivariable model, MR-proADM levels at 48 hours and on day 5 and clearance on day 5 following admission were statistically significant predictive factors of mortality.

CONCLUSIONS

In clinical practice, in ICU patients admitted with SIRS and organ dysfunction, an MR-proADM cut-off point of 1.425 nmol/L helps to identify those with sepsis. An MR-proADM value above 5.626 nmol/L 48 hours after admission was associated with a high risk of death.

Diagnostic and Prognostic Validity of Proadrenomedullin among Neonates with Sepsis in Tertiary Care Hospitals of Southern India

Introduction

To evaluate Proadrenomedullin (Pro-ADM) as the diagnostic and prognostic marker in neonatal sepsis.

Materials and Methods

In this cross-sectional study, Pro-ADM levels were estimated in 54 neonates with clinical sepsis and positive sepsis screen (cases) and 54 controls without clinical sepsis. Repeat Pro-ADM levels were estimated after 72 hours in cases. Pro-ADM levels were compared with the clinical outcome.

Results and Discussion

Median Pro-ADM levels in cases were 31.8 (IQR: 27.8-39.4) pmol/ml which was significantly higher than controls 5.1 (IQR; 3.1-7.7) pmol/ml. From the constructed ROC curve, a value of 14.5 pmol/ml was taken as the cut-off for sepsis. Pro-ADM had 100% sensitivity, specificity, and positive predictive values (PPV) in detecting sepsis at 14.5 pmol/ml. Among cases, a decrease in Pro-ADM level by 10 pmol/ml was associated with 99% survival. Pro-ADM value of 35 pmol/ml had 100% specificity and PPV in predicting mortality.

Conclusion

Pro-ADM can be used as a single biomarker for detecting neonatal sepsis, predicting clinical outcome and prognosis.

MR-proADM: A New Biomarker for Early Diagnosis of Sepsis in Burned Patients

Mid regional pro-adrenomedullin (MR-proADM) has been used as a marker of sepsis, but its dynamics and role in a burn injury setting has not been tested. In a prospective observational study, we included 42 consecutive patients with >15% TBSA. Daily blood specimens collected over the initial 20 days of treatment were submitted for laboratory analysis of MR-proADM and procalcitonin (PCT) via immunoluminometric sandwich assay (Kryptor, BRAHMS, Berlin, Germany). In patients with an absence of sepsis, an initial increase in MR-proADM and PCT levels was noted post-burn injury, peaking on the second day postadmission and thereafter demonstrated a continued decline in MR-proADM and PCT levels. In those patients who went on to develop sepsis (n = 27, 64.3%), the levels of MR-proADM and PCT were significantly higher (P < .001) on days categorized as septic, than on days categorized as nonseptic. The increase in PCT levels was noted on the first day to be categorized as septic. In contrast, the MR-proADM levels demonstrated an increase one day earlier. The optimal relationship between the specificity and sensitivity of MR-proADM and PCT for the detection of sepsis was an increase of 31% and at least 0.015 nmol/L (area under curve 0.76) or of >39% and at least 0.15 µg/L (area under the curve 0.83), respectively. Burn injury is associated with increased levels of MR-proADM. Subsequent increases may be considered as diagnostic of sepsis onset. In this context, PCT displayed higher specificity and sensitivity, while MR-proADM may be more suitable for the early recognition of sepsis (ClinicalTrials.gov number, NCT01055587).

Prognostic performance of MR-pro-adrenomedullin in patients with community acquired pneumonia in the Emergency Department compared to clinical severity scores PSI and CURB

AIM

(i) evaluate the performance of MR-pro-ADM in reflecting the outcome and risk for CAP patients in the emergency department, and (ii) compare the prognostic performance of MR-pro-ADM with that of clinical scores PSI and CURB65.

METHODS

Observational prospective, single-center study in patients with suspected community acquired pneumonia (CAP). Eighty one patients underwent full clinical and laboratory assessment as by protocol, and were followed up a 28 days. Primary endpoints measured were: death, death at 14 days, non-invasive mechanical ventilation (NIMV), endotracheal intubation (EI), ICU admission, overall hospital stay >10 days, emergency department stay >4 days. The discriminative performance of MR-pro-ADM and clinical scores was assessed by AUROC analysis.

RESULTS

The distribution for MR-pro-ADM followed an upward trend, increasing with the increase of both PSI (p<0.001) and CURB65 (p<0.001) classes. However, the difference between MRproADM values and score classes was significant only in the case of CURB65 classes 0 and 1 (p = 0.046), 2 (p = 0.013), and 3 (p = 0.011); and with PSI classes 5, 3 (p = 0.044), and 1 (p = 0.020). As to the differences among variables for the six end-points, MR-pro-ADM values in the two groups selected for each considered end-point differed in a statistically significant manner for all endpoints. Both PSI and CURB65 differed significantly for all end-points, except for stay in the ED longer than 4 days and the hospital stay longer than 10 days and endotracheal intubation (only PSI classes differed with statistical significance). ROC analyses evidenced that MR-pro-ADM values gave the greatest AUC for the prediction of death, endotracheal intubation, hospital stay >10 days and DE stay >4 days, compared to the PSI and CURB (though difference not statistically significant). For each endpoint measured, the best thresholds values for Mr-pro-ADM were: 1.6 (specificity 76.5%; sensitivity 77.8%) for death; 2.5 (specificity 88.9%; sensitivity 80.0%) for death at 14 days; 1.5 (specificity 77.0%; sensitivity 87.5%) for NIMV; 2.4 (specificity 88.7%; sensitivity 83.3%) for endotracheal intubation; 0.9 (specificity 53.5%; sensitivity 70.6%) for DE stay greater than 4 days; 1.9 (specificity 82.1%; sensitivity 55.3%) for hospital stay greater than 10 days. The AUC for the combination of MR-pro-ADM and PSI was 81.29% [63.41%-99.17%], but not in a statistically significant manner compared to the AUCs of the single predictors. Conversely, the AUC for the combination of MR-pro-ADM and CURB65 was 87.58% [75.54%-99.62%], which was significantly greater than the AUC of CURB65 (p = 0.047) or PSI (p = 0.017) alone.

CONCLUSIONS

The present study confirms that assessment of MR-pro-ADM levels in CAP patients in addition to CURB scores increases the prognostic accuracy of CURB alone and may help rule out discrepancies arising from flawed clinical severity classification. With particular reference to patients scoring in the upper classes of CURB and PSI, MR-pro-ADM values provided additional information towards a better risk stratification of those patients. In particular, our results pointed towards two MR-pro-ADM threshold values that appear to predict with a good degree of accuracy the patient's need for non-invasive mechanical ventilation, endotracheal intubation, or intensive care. This aspect, however, deserves further investigation.

Intramyocardial Injection of Recombinant Adeno-Associated Viral Vector Coexpressing PR39/Adrenomedullin Enhances Angiogenesis and Reduces Apoptosis in a Rat Myocardial Infarction Model

Cotransfer of angiogenic and antiapoptotic genes could be the basis of new gene therapy strategies for myocardial infarction. In this study, rAAV-PR39-ADM, coexpressing antimicrobial peptide (PR39) and adrenomedullin (ADM), was designed with the mediation of recombinant adeno-associated virus. In vitro, CRL-1730 cells were divided into four groups, namely, the sham group, the AAV-null group, the NS (normal saline) group, and the PR39-ADM group. Immunocytochemistry analysis, CCK-8 assays, Matrigel assays, and apoptotic analysis were performed; in vivo, myocardial infarction model was established through ligation of the left coronary artery on rats, and treatment groups corresponded to those used in vitro. Myocardial injury, cardiac performance, and the extent of myocardial apoptosis were assessed. Results suggested that rAAV-PR39-ADM administration after myocardial infarction improved cell viability and cardiac function, attenuated apoptosis and myocardial injury, and promoted angiogenesis. Subsequently, levels of 6×His, HIF-1α, VEGF, p-Akt, Akt, ADM, Bcl-2, and Bax were measured by western blot. rAAV-PR39-ADM increased p-Akt, HIF-1α, and VEGF levels and induced higher Bcl-2 expression and lower Bax expression. In conclusion, our results demonstrate that rAAV-PR39-ADM mitigates myocardial injury by promoting angiogenesis and reducing apoptosis. This study suggests a potential novel gene therapy-based method that could be used clinically for myocardial infarction.

Adrenomedullin Is Associated With Surgical Trauma and Impaired Renal Function in Vascular Surgery Patients

BACKGROUND:

Patients undergoing vascular surgery are prone to perioperative organ injury because of both higher prevalence of cardiovascular risk factors and the extent of surgery. Early detection of organ failure is essential to facilitate appropriate medical care. Midregional pro-adrenomedullin (MR-proADM) has been investigated in acute medical care settings to guide clinical decision-making regarding patient pathways and to identify patients prone to imminent cardiovascular or inflammatory complications. In this study, we evaluated the impact of perioperative MR-proADM levels as an early marker of perioperative cardiovascular and inflammatory stress reactions and kidney injury.

METHODS:

The study was conducted as a monocentric, prospective, noninterventional trial at Hannover Medical School, Germany. A total of 454 consecutive patients who underwent open vascular surgery were followed from the day prior to until 30 days after surgery. The composite primary end point was defined as the occurrence of major adverse cardiac events (MACEs), acute kidney injury (AKI), or systemic inflammatory response syndrome (SIRS). Measurements were correlated with both medical history and postoperative MACE, AKI, or SIRS using univariate and multivariate regression analysis.

RESULTS:

One hundred thirty-nine (31%) of the patients reached the primary end point within the study interval. Midregional pro-adrenomedullin change was associated with the combined primary end point and with the intensity of surgical trauma. Midregional pro-adrenomedullin change was increased in patients reaching the secondary end points, SIRS (optimal cutoff: 0.2 nmol/L) and AKI (optimal cutoff: 0.7 nmol/L), but not in patients with MACEs.

CONCLUSION:

Increased levels of MR-proADM within the perioperative setting (1) were linked to the invasiveness of surgery and (2) identified patients with ongoing loss of renal function. Increased MR-proADM levels may therefore identify a subgroup of patients prone to excessive cardiovascular stress but did not directly correlate with adverse cardiac events. Consistently low levels of MR-proADM may identify a subgroup of patients with acceptable low risk to guide discharge from high-density care units.

Blood biomarkers associated with neurological deterioration in patients with acute penetrating artery territory infarction: A multicenter prospective observational study

Background and purpose

Neurological deterioration in acute penetrating artery territory infarction is unpredictable and associated with unfavorable clinical outcomes. The aim of this prospective study was to clarify the cause of neurological worsening and predict clinical outcomes using blood biomarkers.

Methods

Eight Japanese stroke centers participated. Blood samples were obtained within 24 h (the first sampling) and on day 7 in hospital (the second sampling) in patients with penetrating artery territory infarction, arriving within two days of stroke onset. Symptomatic worsening was defined as a minimum increase of one point on the National Institutes of Health Stroke Scale. Poor outcome was defined as a modified Rankin Scale score of ≥3 at 90 days after ictus.

Results

Of the 89 patients, 25 (28%) had symptomatic worsening, and 25 (28%) had a poor outcome. Although tumor necrosis factor-alpha, high-sensitivity C-reactive protein levels were significantly increased in both groups at the second sampling, soluble lectin-like oxidized low-density lipoprotein receptor-1, CD40 ligand, and pro-adrenomedullin levels were significantly increased and ADAMTS13 activity was decreased in symptomatic worsening patients ( p < 0.05 for all). After multivariate adjustment, a low number of CD34+ cells at the first sampling was an independent predictor of poor outcome (odds ratio, 0.20; 95% confidence interval, 0.04–0.74, p = 0.011, per 1 cell/µl increase).

Conclusions

Blood biomarkers associated with atherosclerotic processes seem to be an indication for symptomatic worsening, and the number of CD34+ cells may help to predict three-month functional outcome in patients with penetrating artery territory infarction.

New role of biomarkers: mid-regional pro-adrenomedullin, the biomarker of organ failure

Mid-regional pro-adrenomedullin (MR-proADM) has a good biomarker profile: its half-life is several hours, and its plasma concentrations can be determined in clinical practice, it is essentially irrelevant, but proportionally represents the levels and activity of adrenomedullin (ADM). ADM synthesis is widely distributed in tissues, including bone, adrenal cortex, kidney, lung, blood vessels and heart. Its fundamental biological effects include vasodilator, positive inotropic, diuretic, natriuretic and bronchodilator. It has been described high levels in septic patients, interacting directly with the relaxation of vascular tone, triggering hypotension of these patients. It is also found high levels in other diseases such as hypertension, heart failure, respiratory failure, renal failure, cirrhosis and cancer. MR-proADM has been identified as a prognostic marker, stratifying the mortality risk in patients with sepsis in emergency department (ED) and ICU. Evolutionary MR-proADM levels and clearance marker to the 2nd-5th days of admission help to determine the poor performance and the risk of mortality in patients with severe sepsis admitted to the ICU. The MR-proADM levels are more effective than procalcitonin (PCT) and C-reactive protein (CRP) levels to determine an unfavorable outcome and the risk of mortality in patients with sepsis admitted to the ICU. It has also proved useful in patients diagnosed with organ dysfunction of infectious etiology. MR-proADM levels are independent of the germ conversely it is related to the magnitude of organ failure and therefore severity. We consider advisable incorporating the MR-proADM the panel of biomarkers necessary for the diagnosis and treatment of critically ill patients admitted to the ICU with severe sepsis. The combined PCT and MR-proADM levels could represent a valid tool in the clinical practice to timely identify patients with bacterial infections and guide the diagnosis and treatment of sepsis and septic shock.

Prognostic value of mid-regional pro-adrenomedullin (MR-proADM) in patients with community-acquired pneumonia: a systematic review and meta-analysis

Background

The early identification of patients at risk of dying from community-acquired pneumonia (CAP) is critical for their treatment and for defining hospital resource consumption. Mid-regional pro-adrenomedullin (MR-proADM) has been extensively investigated for its prognostic value in CAP. However, the results are conflicting. The purpose of the present meta-analysis was to explore the diagnostic accuracy of MR-proADM for predicting mortality in patients suffering from CAP, particularly emergency department (ED) patients.

Method

We systematically searched the PubMed, Embase, Web of Knowledge and Cochrane databases. Studies were included if a 2 × 2 contingency table could be constructed based on both the MR-proADM level and the complications or mortality of patients diagnosed with CAP. The prognostic accuracy of MR-proADM in CAP was assessed using the bivariate meta-analysis model. We used the Q-test and I² index to evaluate heterogeneity.

Results

MR-proADM displayed moderate diagnostic accuracy for predicting complications in CAP, with an overall area under the SROC curve (AUC) of 0.74 (95 % CI: 0.70–0.78). Eight studies with a total of 4119 patients in the emergency department (ED) were included. An elevated MR-proADM level was associated with increased risk of death from CAP (RR 6.16, 95 % CI 4.71–8.06); the I² value was 0.0 %, and a fixed-effects model was used to pool RR. The pooled sensitivity and specificity were 0.74 (95 % CI: 0.67–0.79) and 0.73 (95 % CI: 0.70–0.77), respectively. The positive likelihood ratio (PLR) and negative likelihood ratio (NLR) were 2.8 (95 % CI, 2.3–3.3) and 0.36 (95 % CI, 0.29–0.45), respectively. In addition, the diagnostic odds ratio (DOR) was 8 (95 % CI, 5–11), and the overall area under the SROC curve was 0.76 (95 % CI, 0.72–0.80).

Conclusions

Our study has demonstrated that MR-proADM is predictive of increased complications and higher mortality rates in patients suffering from CAP. Future studies are warranted to determine the prognostic accuracy of MR-proADM in conjunction with severity scores or other biomarkers and to determine an optimal cut-off level.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-016-1566-3) contains supplementary material, which is available to authorized users.

Mid-regional proadrenomedullin: An early marker of response in critically ill patients with severe community-acquired pneumonia?

BACKGROUND

Mid-regional proadrenomedullin (MR-proADM) is a novel biomarker with potential prognostic utility in patients with community-acquired pneumonia (CAP).

PURPOSE

To evaluate the value of MR-proADM levels at ICU admission for further severity stratification and outcome prediction, and its kinetics as an early predictor of response in severe CAP (SCAP).

MATERIALS AND METHODS

Prospective, single-center, cohort study of 19 SCAP patients admitted to the ICU within 12h after the first antibiotic dose.

RESULTS

At ICU admission median MR-proADM was 3.58nmol/l (IQR: 2.83-10.00). No significant association was found between its serum levels at admission and severity assessed by SAPS II (Spearman's correlation=0.24, p=0.31) or SOFA score (SOFA<10: <3.45nmol/l vs. SOFA≥10: 3.90nmol/l, p=0.74). Hospital and one-year mortality were 26% and 32%, respectively. No significant difference in median MR-proADM serum levels was found between survivors and non-survivors and its accuracy to predict hospital mortality was bad (aROC 0.53). After 48h of antibiotic therapy, MR-proADM decreased in all but 5 patients (median -20%; IQR -56% to +0.1%). Its kinetics measured by the percent change from baseline was a good predictor of clinical response (aROC 0.80). The best discrimination was achieved by classifying patients according to whether MR-proADM decreased or not within 48h. No decrease in MR-proADM serum levels significantly increased the chances of dying independently of general severity (SAPS II-adjusted OR 174; 95% CI 2-15,422; p=0.024).

CONCLUSIONS

In SCAP patients, a decrease in MR-proADM serum levels in the first 48h after ICU admission was a good predictor of clinical response and better outcome.

Cerebellar Adrenomedullinergic System. Role in Cardiovascular Regulation

Adrenomedullin (AM) is a multifunctional peptide which exerts numerous biological activities through the activation of AM1 (CRLR + RAMP2) and AM2 (CRLR + RAMP3) receptors. AM immunoreactivity, AM binding sites and CRLR, RAMP1, RAMP2 and RAMP3 are expressed in rat cerebellar vermis. AM binding sites are discretely and differentially distributed in the rat cerebellar cortex with higher levels detected in SHR when compared with WKY rats. In addition, there is an up-regulation of cerebellar CGRP1 (CRLR + RAMP1) and AM2 (CRLR + RAMP3) receptors and a down-regulation of AM1 (CRLR + RAMP2) receptor during hypertension associated with a decreased AM expression. These changes may constitute a mechanism which contributes to the development of hypertension, and supports the notion that cerebellar AM is involved in the regulation of blood pressure. Cerebellar AM activates ERK, increases cAMP, cGMP and nitric oxide, and decreases antioxidant enzyme activity. These effects are mediated through AM₁ receptor since they are blunted by AM(22-52). AM-stimulated cAMP production is mediated through AM2 and CGRP receptors. In vivo administration of AM into the cerebellar vermis caused a profound, specific and dose-dependent hypotensive effect in SHR, but not in normotensive WKY rats. This effect was mediated through AM1 receptor since it was abolished by AM(22-52). In addition, AM injected into the cerebellar vermis reduced vasopressor response to footshock stress. These findings demonstrate dysregulation of cerebellar AM system during hypertension, and suggest that cerebellar AM plays an important role in the regulation of blood pressure. Likewise, they constitute a novel mechanism of blood pressure control which has not been described so far.

Prospective evaluation of biomarkers for prediction of quality of life in community-acquired pneumonia

Background:

Most clinical research investigated prognostic biomarkers for their ability to predict cardiovascular events or mortality. It is unknown whether biomarkers allow prediction of quality of life (QoL) after survival of the acute event. Herein, we investigated the prognostic potential of well-established inflammatory/cardiovascular blood biomarkers including white blood cells (WBC), C-reactive protein (CRP), procalcitonin (PCT), pro-adrenomedullin (proADM) and pro-atrial natriuretic peptide (proANP) in regard to a decline in QoL in a well-defined cohort of patients with community-acquired pneumonia (CAP).

Methods:

Within this secondary analysis including 753 patients with a final inpatient diagnosis of CAP from a multicenter trial, we investigated associations between admission biomarker levels and decline in QoL assessed by the EQ-5D health questionnaire from admission to day 30 and after 6 years.

Results:

Admission proADM and proANP levels significantly predicted decline of the weighted EQ-5D index after 30 days (n=753) with adjusted odds ratios (ORs) of 2.0 ([95% CI 1.1–3.8]; p=0.027) and 3.7 ([95% CI 2.2–6.0]; p<0.001). Results for 6-year outcomes (n=349) were similar with ORs of 3.3 ([95% CI 1.3–8.3]; p=0.012) and 6.2 ([95% CI 2.7–14.2]; p<0.001). The markers were associated with most of the different QoL dimensions including mobility, self-care, and usual activities, but not pain/discomfort and to a lesser degree anxiety/depression and the visual analogue scale (VAS). Initial WBC, PCT and CRP values did not well predict QoL at any time point.

Conclusions:

ProADM and proANP accurately predict short- and long-term decline in QoL across most dimensions in CAP patients. It will be interesting to reveal underlying physiopathology in future studies.

Ubiquitous expression and multiple functions of biologically active peptides

Biologically active peptides are widely expressed throughout in human bodies. For example, endothelin-1 and adrenomedullin are expressed in almost all types of cells, including neurons, glial cells, fibroblasts, macrophages, cardiomyocytes, vascular endothelial cells, epithelial cells and cancer cells of various origins. Expression of both these peptides is induced by stimuli, such as hypoxia and inflammatory cytokines. They have a variety of biological functions, such as effects on brain function, hormone secretion, the cardiovascular system and cell proliferation. By contrast, orexins (hypocretins) and melanin-concentrating hormone (MCH) are specifically expressed in the hypothalamus, particularly in the lateral hypothalamus, although very low concentrations of these peptides are found in the peripheral tissues. Orexins and MCH play coordinated, but distinct physiological roles in the regulation of sleep-wake cycle, appetite, emotion and other brain functions. The cardiovascular system is regulated by cardiovascular peptides, such as natriuretic peptides, endothelins and angiotensin II. The renin-angiotensin system (RAS) is one of the most classical regulatory systems on blood pressure, electrolytes and kidney. (Pro)renin receptor is a novel member of the RAS and may be related to the pathophysiology of microvascular complications of hypertension and diabetes mellitus. Moreover, (pro)renin receptor forms a functional complex with vacuolar-type H(+)-ATPase, which plays an important physiological role in maintaining the acidic environment of intracellular compartments including secretory vesicles. Perhaps, the complex of (pro)renin receptor and vacuolar-type H(+)-ATPase may be important for the post-translational processing and secretion of many biologically active peptides.

Prognostic value of pro-adrenomedullin, procalcitonin and C-reactive protein in predicting outcome of febrile urinary tract infection

Bacterial infections such as febrile urinary tract infection (fUTI) may run a complicated course that is difficult to foretell on clinical evaluation only. Because the conventional biomarkers erythrocyte sedimentation rate (ESR), leucocyte count, C-reactive protein (CRP) and procalcitonin (PCT) have a limited role in the prediction of a complicated course of disease, a new biomarker-plasma midregional pro-adrenomedullin (MR-proADM)-was evaluated in patients with f UTI. We conducted a prospective multicentre cohort study including consecutive patients with f UTI at 35 primary-care centres and eight emergency departments. Clinical and microbiological data were collected and plasma biomarker levels were measured at presentation to the physician. Survival was assessed after 30 days. Of 494 fUTI patients, median age was 67 (interquartile range 49-78) years, 40% were male; two-thirds of them had significant co-existing medical conditions. Median MR-proADM level was 1.42 (interquartile range 0.67-1.57) nM; significantly elevated MR-proADM levels were measured in patients with bacteraemia, those admitted to the intensive care unit, and in 30-day and 90-day non-survivors, compared with patients without these characteristics. The diagnostic accuracy for predicting 30-day mortality in fUTI, reflected by the area-under-the-curve of receiver operating characteristics were: MR-proADM 0.83 (95% CI 0.71-0.94), PCT 0.71 (95% CI 0.56-0.85); whereas CRP, ESR and leucocyte count lacked diagnostic value in this respect. This study shows that MR-proADM assessed on first contact predicts a complicated course of disease and 30-day mortality in patients with fUTI and in this respect has a higher discriminating accuracy than the currently available biomarkers ESR, CRP, PCT and leucocyte count.

Midregional proadrenomedullin predicts mortality and major adverse cardiac events in patients presenting with chest pain: results from the CHOPIN trial

OBJECTIVES

Chest pain is a common complaint to emergency departments (EDs) and clinical risk factors are used to predict which patients are at risk for worse outcomes and mortality. The goal was to assess the novel biomarker midregional proadrenomedullin (MR-proADM) in prediction of mortality and major adverse cardiac events (MACE).

METHODS

This was a subanalysis of the CHOPIN study, a 16-center prospective trial that enrolled 2,071 patients presenting with chest pain within 6 hours of onset. The primary endpoint was 6-month all-cause mortality and the secondary endpoint was 30-day and 6-month MACE: ED visits or hospitalization for acute myocardial infarction, unstable angina, reinfarction, revascularization, and heart failure.

RESULTS

MR-proADM performed similarly to troponin (cTnI; c-statistic = 0.845 and 0.794, respectively) for mortality prediction in all subjects and had similar results in those with noncardiac diagnoses. MR-proADM concentrations were stratified by decile, and the cohort in the top decile had a 9.8% 6-month mortality risk versus 0.9% risk for those in the bottom nine deciles (p < 0.0001). MR-proADM, history of coronary artery disease (CAD), and hypertension were predictors of short-term MACE, while history of CAD, hypertension, cTnI, and MR-proADM were predictors of long-term MACE.

CONCLUSIONS

In patients with chest pain, MR-proADM predicts mortality and MACE in all-comers with chest pain and has similar prediction in those with a noncardiac diagnosis. This exploratory analysis is primarily hypotheses-generating and future prospective studies to identify its utility in risk stratification should be considered.

Postoperative pro-adrenomedullin levels predict mortality in thoracic surgery patients: comparison with Acute Physiology and Chronic Health Evaluation IV Score*

OBJECTIVES

Risk assessment in ICU patients using commonly used prognostic models may be influenced using different data definitions and by errors in data collection. We investigated whether a set of biomarkers (procalcitonin, MR-pro-adrenomedullin, CT-pro-endothelin-1, CT-pro-arginine vasopressin, and MR-pro-atrial natriuretic peptide), alone or as a panel, could be useful in postoperative risk assessment for hospital mortality in comparison with the Acute Physiology and Chronic Health Evaluation IV score.

DESIGN

In a prospective observational cohort study, we analyzed 800 consecutive patients undergoing elective cardiac surgery. We assessed biomarker levels on admission to the ICU and every 6 hours thereafter for 24 hours. For every postoperative time point and for every biomarker, we determined the predictive value for hospital mortality and made a comparison with the Acute Physiology and Chronic Health Evaluation IV score.

SETTING

Intensive care of an academic referral hospital.

PATIENTS

A total of 800 consecutive patients undergoing elective cardiac surgery.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

MR-pro-adrenomedullin is a good predictor of mortality (c-statistic at time point 6 hr after admission to the ICU, 0.940; 95% CI, 0.918-0.956) and performed better than the Acute Physiology and Chronic Health Evaluation IV score (c-statistic, 0.842; 95% CI, 0.811-0.868). The c-statistic did not change significantly on the time points 6, 12, and 18 hours after admission. Using a cutoff value for proadrenomedullin taken 6 hours after admission on ICU (time point 2) of 3.2 nmol/L sensitivity was 81.8% and specificity 93.9%, the positive likelihood ratio was 13.3, positive predictive value was 31.0%, and negative predictive value was 99.4%. Patients with a MR-pro-adrenomedullin above this cutoff level had an odds ratio of 68.9 (95% CI, 22.2-213.1) for not surviving their hospital stay. The other biomarkers had less predictive power.

CONCLUSIONS

In elective cardiac surgery, MR-pro-adrenomedullin measured between 6 and 18 hours after admission to the ICU is a better predictor of hospital mortality in comparison with the Acute Physiology and Chronic Health Evaluation IV score.

Plasma concentrations of adrenomedullin and natriuretic peptides in patients with essential hypertension

This study was designed to assess any changes in the plasma concentrations of adrenomedullin (ADM) and atrial and brain natriuretic peptide (ANP and BNP, respectively), and to investigate their pathophysiological roles in patients with essential hypertension (EH). The plasma ADM, ANP and BNP concentrations were measured in 64 patients with untreated EH and 35 normotensive control subjects. After 4 weeks of effective antihypertensive therapy with oral drugs for the hypertensive patients, the plasma concentrations of ADM, ANP and BNP in the hypertensive patients were measured again. The plasma concentrations of ADM, ANP and BNP were significantly higher in the hypertensive patients than those in the control subjects, and the concentrations increased with the clinical stage. Furthermore, the hypertensive patients exhibited increased mean arterial pressure (MAP), blood urea nitrogen (BUN), serum creatinine (Scr) and decreased glomerular filtration rates (GFRs) compared with the control subjects. The plasma ADM concentration was not only correlated with BUN, Scr and the GFR, but was also associated with the MAP and the plasma levels of ANP and BNP. Following effective antihypertensive therapy with oral medication for 4 weeks, the plasma concentrations of ADM, ANP and BNP were significantly, but not sharply, decreased. In conclusion, ADM, along with ANP and BNP, may be involved in the mechanisms acting against a further increase in blood pressure and may be useful biomarkers for the diagnosis and treatment of hypertensive patients.

Tumor-expressed adrenomedullin accelerates breast cancer bone metastasis

Introduction

Adrenomedullin (AM) is secreted by breast cancer cells and increased by hypoxia. It is a multifunctional peptide that stimulates angiogenesis and proliferation. The peptide is also a potent paracrine stimulator of osteoblasts and bone formation, suggesting a role in skeletal metastases—a major site of treatment-refractory tumor growth in patients with advanced disease.

Methods

The role of adrenomedullin in bone metastases was tested by stable overexpression in MDA-MB-231 breast cancer cells, which cause osteolytic bone metastases in a standard animal model. Cells with fivefold increased expression of AM were characterized in vitro, inoculated into immunodeficient mice and compared for their ability to form bone metastases versus control subclones. Bone destruction was monitored by X-ray, and tumor burden and osteoclast numbers were determined by quantitative histomorphometry. The effects of AM overexpression on tumor growth and angiogenesis in the mammary fat pad were determined. The effects of AM peptide on osteoclast-like multinucleated cell formation were tested in vitro. A small-molecule AM antagonist was tested for its effects on AM-stimulated ex vivo bone cell cultures and co-cultures with tumor cells, where responses of tumor and bone were distinguished by species-specific real-time PCR.

Results

Overexpression of AM mRNA did not alter cell proliferation in vitro, expression of tumor-secreted factors or cell cycle progression. AM-overexpressing cells caused osteolytic bone metastases to develop more rapidly, which was accompanied by decreased survival. In the mammary fat pad, tumors grew more rapidly with unchanged blood vessel formation. Tumor growth in the bone was also more rapid, and osteoclasts were increased. AM peptide potently stimulated bone cultures ex vivo; responses that were blocked by small-molecule adrenomedullin antagonists in the absence of cellular toxicity. Antagonist treatment dramatically suppressed tumor growth in bone and decreased markers of osteoclast activity.

Conclusions

The results identify AM as a target for therapeutic intervention against bone metastases. Adrenomedullin potentiates osteolytic responses in bone to metastatic breast cancer cells. Small-molecule antagonists can effectively block bone-mediated responses to tumor-secreted adrenomedullin, and such agents warrant development for testing in vivo.

Electronic supplementary material

The online version of this article (doi:10.1186/s13058-014-0458-y) contains supplementary material, which is available to authorized users.

Biomarkers for community-acquired pneumonia in the emergency department

Community-acquired pneumonia is one of the most common reasons for emergency department (ED) visits in children and adults. Despite its prevalence, there are many challenges to proper diagnosis and management of pneumonia. There is no accurate and timely etiologic gold standard to differentiate bacterial from viral disease, and there are limitations with precise risk stratification of patients to ensure appropriate site-of-care decisions. Clinical factors obtained by history and physical examination have limited the ability to diagnose pneumonia etiology and severity. Biomarkers offer information about the host response to infection and pathogen activity within the host that can serve to augment clinical features in decision-making. As science and technology progress, novel biomarkers offer great potential in aiding critical decisions for patients with pneumonia. This review summarizes existing knowledge about biomarkers of host response and pathogen activity, in addition to briefly reviewing emerging biomarkers using novel technologies.

Performance evaluation of MR-proadrenomedullin and other scoring systems in severe sepsis with pneumonia

BACKGROUND

In sepsis, risk assessment is as crucial as early and accurate diagnosis. In this study, we aimed to evaluate the prognostic value of mid-regional proadrenomedullin (MR-proADM) with other scoring systems in severe sepsis and septic shock patients due to community acquired pneumonia (CAP).

METHODS

Patients were divided into 2 groups as severe sepsis and septic shock due to CAP (group 1, n=31) and only CAP group (group 2, n=26). Serum MR-proADM, procalcitonin (PCT), C-reactive protein (CRP), and d-dimer level were analyzed. Acute Physiological and Chronic Health Evaluation (APACHE) II score, Sequential Organ Failure Assessment (SOFA) score, and Pneumonia Severity Index (PSI) were performed for all patients.

RESULTS

There was no difference between groups in terms of serum MR-proADM levels (P=0.780). Serum MR-proADM was not found a significant value for the prediction of death within the 4 and 8 weeks in all patients. SOFA score was the most significant to predict mortality in 4 and 8 weeks (P<0.001). The combination of SOFA score and serum MR-proADM was a strong factor to predict death in 4 weeks (specifity 86.8% and sensitivity 66.7%). The combination of MR-proADM, SOFA score, and APACHE II score was found 75.0% sensitive and 71.4% specific to predict mortality within 4 weeks in group 1.

CONCLUSIONS

The MR-proADM does not correlate with mortality or disease severity to predict mortality. The combination of SOFA, APACHE II scores, and MR-proADM was efficient to predict prognosis and mortality rate in severe sepsis or septic shock patients.

Adrenomedullin deficiency and aging exacerbate ischemic white matter injury after prolonged cerebral hypoperfusion in mice

Adrenomedullin was originally isolated from pheochromocytoma cells and reduces insulin resistance by decreasing oxidative stress. White matter lesions induced by aging and hyperglycemia play a crucial role in cognitive impairment in poststroke patients. Here, we examine whether adrenomedullin deficiency and aging exacerbate ischemic white matter injury after prolonged cerebral hypoperfusion. Adrenomedullin heterozygous, wild-type young/aged mice were subjected to prolonged hypoperfusion. Prolonged cerebral hypoperfusion followed by immunohistochemical analysis was used to evaluate white matter injury. After prolonged hypoperfusion, white matter damage progressed in a time-dependent manner in AM^+/− group compared with the wild-type group. The number of oligodendrocyte progenitor cells gradually increased after prolonged hypoperfusion, whereas oligodendrocytes decreased following a transient increase, but the ratio of increase was mild in the AM^+/− group (P < 0.05). Oxidative stress was detected in oligodendrocytes, with a larger increase in the AM^+/− group (P < 0.05). Aged mice showed the same tendency, but white matter damage was worse, especially in the aged AM^+/− group. Our results demonstrated that white matter injury was increased in adrenomedullin deficiency, which induced oxidative stress. White matter injury was more exacerbated because of hyperglycemia in aged AM^+/− group. Adrenomedullin may be an important target in the control of ischemic white matter injury.

New vasoactive peptides in cirrhosis: organ extraction and relation to the vasodilatory state

BACKGROUND

Patients with cirrhosis have substantial circulatory imbalance between vasoconstrictive and vasodilating forces. The study of circulatory vasoactive peptides may provide important pathophysiological information. This study aimed to assess concentrations, organ extraction and relations to haemodynamic changes in the pro-peptides copeptin, proadrenomedullin and pro-atrial natriuretic peptide (proANP) in patients with cirrhosis.

MATERIALS AND METHODS

Fifty-four cirrhotic patients and 15 controls were characterized haemodynamically during a liver vein catheterization. Copeptin, proadrenomedullin and proANP were measured in hepatic and renal veins and the femoral artery.

RESULTS

We found no differences in concentrations of copeptin and proadrenomedullin between patients and controls. ProANPs were higher in cirrhotic patients, median 138 pm (25/75 percentiles 101-194) compared with controls, median 91 pm (25/75 percentiles 82-153) P=0·02. ProANPs were higher in the femoral artery and renal vein, median 140 pm and 116 pm (25/75 percentiles 109-191 and 92-164, respectively), compared with controls, median 99 and 81 (25/75 percentiles 85-146 and 66-123) P=0·02 and P=0·007, respectively. We found no extraction of copeptin, proadrenomedullin or proANP over the liver. Copeptin correlated with portal pressure (R=0·50, P<0·001). Proadrenomedullin correlated with portal pressure (R=0·48, P<0·001) and heart rate (R=0·36, P<0·01). ProANP correlated with cardiac output (R=0·46, P<0·002) and portal pressure (R=0·32, P<0·02). All propeptides correlated with Child score (R>0·31, P<0·03).

CONCLUSIONS

Pro-atrial natriuretic peptide is elevated in cirrhosis. Copeptin, proadrenomedullin and proANP are related to portal pressure and seem associated with systemic haemodynamics. These propeptides may participate in development and perpetuation of vasodilatation and hyperdynamic circulation in cirrhosis.

Plasma adrenomedullin concentrations in critically ill neonatal foals

Background

Bacterial sepsis remains a leading cause of morbidity and mortality in neonatal foals, but accurate diagnostic and prognostic markers are lacking. Adrenomedullin (AM) is a polypeptide with diverse biologic effects on the cardiovascular system that increases in septic humans and laboratory animals.

Hypotheses

Plasma AM concentration (p[AM]) is increased in septic neonatal foals compared to sick nonseptic and healthy control foals, and p[AM] is predictive of survival in septic neonatal foals.

Animals

Ninety critically ill (42 septic, 48 sick nonseptic) and 61 healthy foals <1 week of age.

Methods

A prospective observational clinical study was performed. Venous blood was collected from critically ill foals at admission and from healthy foals at 24 hours of age. Critically ill foals were categorized as septic or sick nonseptic based on blood culture results and sepsis score. Plasma [AM] was measured by using a commercially available ELISA for horses. Data were analyzed by using the Mann‐Whitney U‐test and P < .05 was considered significant.

Results

Plasma [AM] was not significantly different between septic and sick nonseptic foals (P = .71), but critically ill foals had significantly increased p[AM] compared to healthy controls (P < .0001). In critically ill foals, p[AM] was not predictive of survival (P = .051). A p[AM] cutoff concentration of 0.041 ng/mL provided a test sensitivity of 91% and specificity of 54% to predict illness.

Conclusions and Clinical Relevance

Plasma [AM] shows promise as a marker of health in neonatal foals, but p[AM] increases nonspecifically during perinatal illnesses and is not necessarily associated with sepsis.

Crosstalk between cerebral endothelium and oligodendrocyte

It is now relatively well accepted that the cerebrovascular system does not merely provide inert pipes for blood delivery to the brain. Cerebral endothelial cells may compose an embedded bunker of trophic factors that contribute to brain homeostasis and function. Recent findings suggest that soluble factors from cerebral endothelial cells nourish neighboring cells, such as neurons and astrocytes. Although data are strongest in supporting mechanisms of endothelial-neuron and/or endothelial-astrocyte trophic coupling, it is likely that similar interactions also exist between cerebral endothelial cells and oligodendrocyte lineage cells. In this mini-review, we summarize current advances in the field of endothelial-oligodendrocyte trophic coupling. These endothelial-oligodendrocyte interactions may comprise the oligovascular niche to maintain their cellular functions and sustain ongoing angiogenesis/oligodendrogenesis. Importantly, it should be noted that the cell-cell interactions are not static-the trophic coupling is disturbed under acute phase after brain injury, but would be recovered in the chronic phase to promote brain remodeling and repair. Oligodendrocyte lineage cells play critical roles in white matter function, and under pathological conditions, oligodendrocyte dysfunction lead to white matter damage. Therefore, a deeper understanding of the mechanisms of endothelial-oligodendrocyte trophic coupling may lead to new therapeutic approaches for white matter-related diseases, such as stroke or vascular dementia.

Heart failure biomarkers

Biomarker testing in patients with heart failure (HF) is rapidly expanding. With high-quality research indicating its diagnostic and prognostic capabilities, biomarkers are excellent adjuncts to manage patients with HF. Their superiority lies mainly in their reflection of ongoing pathophysiological events at a cellular level. Monitoring biomarker levels has been shown to provide incremental information on the progression of disease, thus allowing to better tailor treatment and management. Several biomarkers have gained attention in the past decade and continuing research demonstrates the specificity of each biomarker to be used on its own or in combination to improve diagnostic accuracy. This review will provide an insight into the role of such biomarkers, which are widely studied in the setting of HF so as to delineate their role in diagnosing, prognosticating, and titrating HF therapy.