In silico optimization of analogs derived pro-adrenomedullin peptide to evaluate antimicrobial potential.

Diverse computational approaches have been widely used to assist in designing antimicrobial peptides with enhanced activities. This tactic has also been used to address the need for new treatment alternatives to combat resistant bacterial infections. Herein, we have designed eight variants from a natural peptide, pro-adrenomedullin N-terminal 20 peptide (PAMP), using an in silico pattern insertion approach, the Joker algorithm. All the variants show an α-helical conformation, but with differences in the helix percentages according to circular dichroism (CD) results. We found that the C-terminal portion of PAMP may be relevant for its antimicrobial activities, as revealed by the molecular dynamics, CD, and antibacterial results. The analogs showed variable antibacterial potential, but most were not cytotoxic. Nevertheless, PAMP2 exhibited the most potent activities against human and animal-isolated bacteria, showing cytotoxicity only at a substantially higher concentration than its minimal inhibitory concentration (MIC). Our results suggest that the enhanced activity in the profile of PAMP2 may be related to their particular physicochemical properties, along with the adoption of an amphipathic α-helical arrangement with the conserved C-terminus portion. Finally, the peptides designed in this study can constitute scaffolds for the design of improved sequences.

Calcitonin gene-related peptide and intermedin induce phosphorylation of p44/42 MAPK in primary human lymphatic endothelial cells in vitro.

Calcitonin gene-related peptide (CGRP) and adrenomedullin 2/intermedin (AM2/IMD) play important roles in several pathologies, including cardiovascular disease, migraine and cancer. The efficacy of drugs targeting CGRP signalling axis for the treatment of migraine patients is sometimes offset by side effects (e.g. inflammation and microvascular complications, including aberrant neovascularisation in the skin). Recent studies using animal models implicate CGRP in lymphangiogenesis and lymphatic vessel function. However, whether CGRP or AM2/IMD can act directly on lymphatic endothelial cells is unknown. Here, we found that CGRP and AM2/IMD induced p44/42 MAPK phosphorylation in a time- and dose-dependent manner in primary human dermal lymphatic endothelial cells (HDLEC) in vitro, and thus directly affected these cells. These new findings reveal CGRP and AM2/IMD as novel regulators of LEC biology and warrant further investigation of their roles in the context of pathologies associated with lymphatic function in the skin and other organs, and therapies targeting CGRP signalling axis.

Biologically active adrenomedullin as a marker for residual congestion and early rehospitalization in patients hospitalized for acute heart failure: Data from STRONG-HF.

AIMS: Biologically active adrenomedullin (bio-ADM) is a promising marker of residual congestion. The STRONG-HF trial showed that high-intensity care (HIC) of guideline-directed medical therapy (GDMT) improved congestion and clinical outcomes in heart failure (HF) patients. The association between bio-ADM, decongestion, outcomes and the effect size of HIC of GDMT remains to be elucidated. METHODS AND RESULTS: We measured plasma bio-ADM concentrations in 1005 patients within 2 days prior to anticipated discharge (baseline) and 90 days later. Bio-ADM correlated with most signs of congestion, with the exception of rales. Changes in bio-ADM were strongly correlated with change in congestion status from baseline to day 90 (gamma -0.24; p = 0.0001). Patients in the highest tertile of baseline bio-ADM concentrations were at greater risk than patients in the lowest tertile for the primary outcome of 180-day all-cause mortality or HF rehospitalization (hazard ratio [HR] 2.14, 95% confidence interval [CI] 1.42-3.22) and 180-day HF rehospitalization (HR 2.33, 95% CI 1.38-3.94). Areas under the receiver-operating characteristic curves were 0.5977 (95% CI 0.5561-0.6393), 0.5800 (95% CI 0.5356-0.6243), and 0.6159 (95% CI 0.5711-0.6607) for bio-ADM, N-terminal pro-B-type natriuretic peptide (NT-proBNP) and their combination, respectively, suggesting that both bio-ADM and NT-proBNP provided similarly modest discrimination for this outcome. A trend towards better discrimination by combined bio-ADM and NT-proBNP than NT-proBNP alone was found (p = 0.059). HIC improved the primary outcome, irrespective of baseline bio-ADM concentration (interaction p = 0.37). In contrast to NT-proBNP, the 90-day change in bio-ADM did not differ significantly between HIC and usual care. CONCLUSIONS: Bio-ADM is a marker of congestion and predicts congestion at 3 months after a HF hospitalization. Higher bio-ADM was modestly associated with a higher risk of death and early hospital readmission and may have added value when combined with NT-proBNP.

Leveraging Integrated RNA Sequencing to Decipher Adrenomedullin's Protective Mechanisms in Experimental Bronchopulmonary Dysplasia.

Bronchopulmonary dysplasia (BPD) is a chronic lung disease commonly affecting premature infants, with limited therapeutic options and increased long-term consequences. Adrenomedullin (Adm), a proangiogenic peptide hormone, has been found to protect rodents against experimental BPD. This study aims to elucidate the molecular and cellular mechanisms through which Adm influences BPD pathogenesis using a lipopolysaccharide (LPS)-induced model of experimental BPD in mice. Bulk RNA sequencing of Adm-sufficient (wild-type or Adm+/+) and Adm-haplodeficient (Adm+/-) mice lungs, integrated with single-cell RNA sequencing data, revealed distinct gene expression patterns and cell type alterations associated with Adm deficiency and LPS exposure. Notably, computational integration with cell atlas data revealed that Adm-haplodeficient mouse lungs exhibited gene expression signatures characteristic of increased inflammation, natural killer (NK) cell frequency, and decreased endothelial cell and type II pneumocyte frequency. Furthermore, in silico human BPD patient data analysis supported our cell type frequency finding, highlighting elevated NK cells in BPD infants. These results underscore the protective role of Adm in experimental BPD and emphasize that it is a potential therapeutic target for BPD infants with an inflammatory phenotype.

A Focus on the Pathophysiology of Adrenomedullin Expression: Endothelitis and Organ Damage in Severe Viral and Bacterial Infections.

Adrenomedullin (ADM) is a peptide hormone produced primarily in the adrenal glands, playing a crucial role in various physiological processes. As well as improving vascular integrity and decreasing vascular permeability, ADM acts as a vasodilator, positive inotrope, diuretic, natriuretic and bronchodilator, antagonizing angiotensin II by inhibiting aldosterone secretion. ADM also has antihypertrophic, anti-apoptotic, antifibrotic, antioxidant, angiogenic and immunoregulatory effects and antimicrobial properties. ADM expression is upregulated by hypoxia, inflammation-inducing cytokines, viral or bacterial substances, strength of shear stress, and leakage of blood vessels. These pathological conditions are established during systemic inflammation that can result from infections, surgery, trauma/accidents or burns. The ability to rapidly identify infections and the prognostic, predictive power makes it a valuable tool in severe viral and bacterial infections burdened by high incidence and mortality. This review sheds light on the pathophysiological processes that in severe viral or bacterial infections cause endothelitis up to the development of organ damage, the resulting increase in ADM levels dosed through its more stable peptide mid-regional proadrenomedullin (MR-proADM), the most significant studies that attest to its diagnostic and prognostic accuracy in highlighting the severity of viral or bacterial infections and appropriate therapeutic insights.

Plasma copeptin and markers of arterial disorder in patients with type 2 diabetes, a cross-sectional study.

OBJECTIVES: There is currently limited understanding of the relationship between copeptin, the midregional portion of proadrenomedullin (MRproADM) and the midregional fragment of the N-terminal of proatrial natriuretic peptide (MRproANP), and arterial disorders. Toe brachial index (TBI) and aortic pulse wave velocity (aPWV) are established parameters for detecting arterial disorders. This study evaluated whether copeptin, MRproADM, and MRproANP were associated with TBI and aPWV in patients with type 2 diabetes with no history of cardiovascular disease (CVD). METHODS: In the CARDIPP study, a cross-sectional analysis of 519 patients with type 2 diabetes aged 55-65 years with no history of CVD at baseline, had complete data on copeptin, MRproADM, MRproANP, TBI, and aPWV was performed. Linear regression analysis was used to investigate the associations between conventional CVD risk factors, copeptin, MRproADM, MRproANP, TBI, and aPWV. RESULTS: Copeptin was associated with TBI (ß-0.0020, CI-0.0035- (-0.0005), p = 0.010) and aPWV (ß 0.023, CI 0.002-0.044, p = 0.035). These associations were independent of age, sex, diabetes duration, mean 24-hour ambulatory systolic blood pressure, glycated hemoglobin A1c, total cholesterol, estimated glomerular filtration rate, body mass index, and active smoking. CONCLUSIONS: Plasma copeptin may be a helpful surrogate for identifying individuals at higher risk for arterial disorders. TRIAL REGISTRATION:  ClinicalTrials.gov identifier NCT010497377.

Postoperative bioactive adrenomedullin is associated with the onset of ARDS and adverse outcomes in patients undergoing open thoracoabdominal aortic surgery.

Cytokine-mediated systemic inflammation after open thoracoabdominal aortic aneurysm (TAAA) repairs plays a pivotal role in disrupting circulatory homeostasis, potentially leading to organ dysfunction. The bioactive form of adrenomedullin (bio-ADM) is a peptide hormone with immunomodulatory and vasomotor effects, making it a potential diagnostic agent in these cases. This retrospective, bicentric study, conducted between January 2019 and December 2022, recruited 36 elective open TAAA repair patients in two German centres. Serum and plasma samples were collected at multiple time points to measure bio-ADM levels. The primary objective was to evaluate the association of bio-ADM levels with the onset of acute respiratory distress syndrome (ARDS), with secondary endpoints focusing on mortality and SIRS-related morbidity. Results showed a significant association between postoperative bio-ADM levels (12-48 h after surgery) and the onset of ARDS (p < .001), prolonged ventilation (p = .015 at 12h after surgery), atrial fibrillation (p < .001), and mortality (p = .05 at 24h). The biomarker was also strongly associated with sepsis (p = .01 at 12 h) and multi-organ dysfunction syndrome (MODS) (p = .02 at 24 h after surgery). The study underscores the potential utility of bio-ADM as a diagnostic tool for identifying patients at risk of postoperative complications following open TAAA repairs.

Effect of intracerebroventricular (ICV) injection of adrenomedullin and its interaction with NPY and CCK pathways on food intake regulation in neonatal layer-type chicks.

Adrenomedullin has various physiological roles including appetite regulation. The objective of present study was to determine the effects of ICV injection of adrenomedullin and its interaction with NPY and CCK receptors on food intake regulation. In experiment 1, chickens received ICV injection of saline and adrenomedullin (1, 2, and 3 nmol). In experiment 2, birds injected with saline, B5063 (NPY1 receptor antagonist, 1.25 µg), adrenomedullin (3 nmol) and co-injection of B5063+adrenomedullin. Experiments 3 to 5 were similar to experiment 2 and only SF22 (NPY2 receptor antagonist, 1.25 µg), SML0891 (NPY5 receptor antagonist, 1.25 µg) and CCK4 (1 nmol) were injected instead of B5063. In experiment 6, ICV injection of saline and CCK8s (0.125, 0.25, and 0.5 nmol) were done. In experiment 7, chickens injected with saline, CCK8s (0.125 nmol), adrenomedullin (3 nmol) and co-injection of CCK8s+adrenomedullin. After ICV injection, birds were returned to their individual cages immediately and cumulative food intake was measured at 30, 60, and 120 min after injection. Adrenomedullin (2 and 3 nmol) decreased food intake compared to control group (P < 0.05). Coinjection of B5063+adrenomedullin amplified hypophagic effect of adrenomedullin (P < 0.05). The ICV injection of the CCK8s (0.25 and 0.5 nmol) reduced food intake (P < 0.05). Co-injection of the CCK8s+adrenomedullin significantly potentiated adrenomedullin-induced hypophagia (P < 0.05). Administration of the SF22, SML0891 and CCK4 had no effect on the anorexigenic response evoked by adrenomedullin (P > 0.05). These results suggested that the hypophagic effect of the adrenomedullin is mediated by NPY1 and CCK8s receptors. However, our novel results should form the basis for future experiments.

Adrenomedullin improved endothelial dysfunction via receptor-Akt pathway in rats with obesity-related hypertension.

Obesity-related hypertension (OH) is accompanied by obvious endothelial dysfunction, which contributes to increased peripheral vascular resistance and hypertension. Adrenomedullin (ADM), a multifunctional active peptide, is elevated in obese humans. The OH rats induced by high fat diet (HFD) for 28 weeks and the human umbilical vein endothelial cells (HUVECs)-treated by palmitic acid (PA) were used to investigate the effects of ADM on endothelial dysfunction and the underlying mechanisms. Vascular reactivity was assessed using mesenteric arteriole rings, and the protein expression levels were examined by Western blot analysis. Compared with the control rats, OH rats exhibited hypertension and endothelial dysfunction, along with reduced eNOS protein expression and Akt activation, and increased protein expression of proinflammatory cytokines and ROS levels. Four-week ADM administration improved hypertension and endothelial function, increased eNOS protein expression and Akt activation, and attenuated endothelial inflammation and oxidative stress in OH rats. In vitro experiment, the antagonism of ADM receptors with ADM22-52 and the suppression of Akt signaling with A6730 significantly blocked ADM-caused increase of NO content and activation of eNOS and Akt, and inhibited the anti-inflammatory and anti-oxidant effect of ADM in PA-stimulated HUVECs. These data indicate that endothelial dysfunction in OH rats is partially attributable to the decreased NO level, and the increased inflammation and oxidative stress. ADM improves endothelial function and exerts hypotensive effect depending on the increase of NO, and its anti-inflammatory and anti-oxidant effect via receptor-Akt pathway.

Usefulness of mid-regional proadrenomedullin levels in the resuscitation phase of severely burned patients and its utility in early sepsis detection.

INTRODUCTION: Mid-regional proadrenomedullin (MR-proADM) reflects the adrenomedullin level, which has vasodilatory activity, decreases endothelial permeability, and downregulates proinflammatory cytokines. Sepsis diagnosis in these patients is difficult, and MR-proADM is a widely studied sepsis biomarker. This study evaluates MR-proADM levels during the resuscitation phase, considering the potential influence of haemodynamic changes and its usefulness for the early sepsis detection in burn patients. METHODS: A prospective observational study performed in the Critical Burn Unit. Demographic data, burn characteristics, comorbidities, prognostic/severity scales, and haemodynamic parameters were collected. The resuscitation protocol guided by diuresis, transpulmonary thermodilution, and lactate levels was followed. Blood samples were collected at various time points for biomarker measurement. Biomarker levels, including MR-proADM, C-reactive protein, and procalcitonin were measured during the resuscitation phase and septic episodes. RESULTS: Twenty-seven patients were included, with a mean age of 51 years, a mean total body surface area burn of 41.8%, a mean Abbreviated Burn Severity Index of 9.7, and a mean Baux score of 92. MR-proADM levels were elevated on admission (0.9 ± 0.5 nmol/l) and continued to increase slightly during the resuscitation phase (2.4 ± 2.2 nmol/l). Haemodynamic changes during resuscitation did not significantly affect MR-proADM levels. Twelve of the 27 patients developed sepsis, whose MR-proADM levels were significantly elevated on the day of clinical diagnosis (3.91 ± 2.99 nmol/l) and even the day before (2.57 ± 3.37). Higher MR-proADM levels were associated with greater severity as measured by the Sequential Organ Failure Assessment score. The mean MR-proadrenomedullin values during resuscitation in the patients who died was 3.51 ± 2.30 nmol/l, whereas in the survivors it was 1.28 ± 1.10 nmol/l (p = 0.0001). CONCLUSION: MR-proadrenomedullin values are elevated after thermal injury but are not affected by haemodynamic changes. During septic episodes in burn patients, MR-proADM rises early (the day before sepsis diagnosis). Higher levels of MR-proADM are associated with greater organ dysfunction and mortality.

Mineralised collagen regulated the secretion of adrenomedullin by macrophages to activate the PI3K/AKT signalling pathway to promote bone defect repair.

Biomaterials can affect the osteogenic process by regulating the function of macrophages and transforming the bone immune microenvironment. Mineralised collagen (MC) is an artificial bone that is highly consistent to the microstructure of the native osseous matrix. The studies have confirmed that MC can achieve effective regeneration of bone defects, but the potential mechanism of MC regulating osteogenesis is still unclear. This study confirmed that MC regulate the high expression of adrenomedullin (ADM) in macrophages and promote the osteogenic differentiation, proliferation and migration of BMSCs. Moreover, ADM activated the PI3K/Akt pathway, while the inhibition of PI3K/Akt hindered the proliferation, migration and osteogenic differentiation of BMSCs promoted by ADM. Additionally, the rat mandibular defect model confirmed that ADM promote the repair of mandibular defects, and the inhibition of PI3K/Akt pathway hinders the osteogenic effect of ADM. Our study suggests that MC regulates ADM secretion by macrophages, creates an ideal bone immune microenvironment, activates the PI3K/AKT signalling pathway, and promotes osteogenesis.

Bioactive adrenomedullin as a marker of congestion and disease progression in patients with a systemic right ventricle.

BACKGROUND: Adults with a systemic right ventricle (sRV) are at a high risk for heart failure (HF) hospitalization and mortality. Bioactive adrenomedullin (bio-ADM) has been proposed as a marker of congestion and prognosis in patients with cardiovascular disease. We aimed to evaluate the association between bio-ADM and mortality and HF events in sRV patients. METHODS: Plasma bio-ADM was measured by a novel immunoassay in plasma of 85 sRV patients. A composite endpoint of all-cause mortality and HF events was used as outcome. HF events were defined as onset or progression of HF signs or symptoms requiring hospitalization, initiation or intensification of therapy. Multivariable Cox regression analyses were performed to evaluate the association between bio-ADM and outcome. RESULTS: The mean age of the patients was 37 ± 9 years and 65% were male. Patients with higher plasma bio-ADM concentrations were more often treated with diuretics (p = 0.007), possibly because of signs and/or symptoms of congestion. During a median follow-up of 10.2 years, 33.7% of the patients reached the endpoint. After adjustment for age and N-terminal pro B-type natriuretic peptide (NT-pro BNP), higher bio-ADM levels were associated with a higher risk of the composite endpoint (hazard ratio: 2.09 [95%-confidence interval: 1.15-3.78]). Bio-ADM improved risk prediction when added to NT-proBNP and age (C-statistic improved from 0.748 to 0.776 [p = 0.03]). CONCLUSIONS: Bio-ADM can be considered as a marker of congestion and independent predictor of death and HF events in adult patients with a sRV. Moreover, in terms of risk prediction, it has added value to NT-proBNP.

Variable CGRP family peptide signaling durations and the structural determinants thereof.

Calcitonin gene-related peptides alpha and beta (αCGRP, ßCGRP), adrenomedullin (AM), and adrenomedullin 2/intermedin (AM2/IMD) function in pain signaling, neuroimmune communication, and regulation of the cardiovascular and lymphatic systems by activating either of two class B GPCRs, CLR and CTR, in complex with a RAMP1, -2, or -3 modulatory subunit. Inspired by our recent discovery that AM2/IMD(1-47) activation of CLR-RAMP3 elicits long duration cAMP signaling, here we used a live-cell cAMP biosensor assay to characterize the signaling kinetics of the two CGRP peptides and several bioactive AM and AM2/IMD fragments with variable N-terminal extensions. Remarkably, AM2/IMD(8-47) and AM2/IMD-53 exhibited even longer duration signaling than the 1-47 fragment. AM2/IMD(8-47) was a striking 8-fold longer acting than AM(13-52) at CLR-RAMP3. In contrast, the N-terminal extension of AM had no effect on signaling duration. AM(1-52) and (13-52) were equally short-acting. Analysis of AM2/IMD-AM mid-region chimeras and AM2/IMD R23 and R33 point mutants showed the importance of these residues for long-duration signaling and identified AM2/IMD peptides that exhibited up to 17-fold diminished signaling duration at CLR-RAMP3, while retaining near wildtype signaling potencies. ßCGRP was âˆ¼ 3-fold longer acting than αCGRP at the CGRP (CLR-RAMP1) and the amylin1 (CTR-RAMP1) receptors. Chimeric CGRP peptides showed that the single residue difference near the N-terminus, and the two differences in the mid-region, equally contributed to the longer duration of ßCGRP signaling. This work uncovers key temporal differences in cAMP signaling among the CGRP family peptides, elucidates the structural bases thereof, and provides pharmacological tools for studying long-duration AM2/IMD signaling.

Identification of hypoxic macrophages in glioblastoma with therapeutic potential for vasculature normalization.

Monocyte-derived tumor-associated macrophages (Mo-TAMs) intensively infiltrate diffuse gliomas with remarkable heterogeneity. Using single-cell transcriptomics, we chart a spatially resolved transcriptional landscape of Mo-TAMs across 51 patients with isocitrate dehydrogenase (IDH)-wild-type glioblastomas or IDH-mutant gliomas. We characterize a Mo-TAM subset that is localized to the peri-necrotic niche and skewed by hypoxic niche cues to acquire a hypoxia response signature. Hypoxia-TAM destabilizes endothelial adherens junctions by activating adrenomedullin paracrine signaling, thereby stimulating a hyperpermeable neovasculature that hampers drug delivery in glioblastoma xenografts. Accordingly, genetic ablation or pharmacological blockade of adrenomedullin produced by Hypoxia-TAM restores vascular integrity, improves intratumoral concentration of the anti-tumor agent dabrafenib, and achieves combinatorial therapeutic benefits. Increased proportion of Hypoxia-TAM or adrenomedullin expression is predictive of tumor vessel hyperpermeability and a worse prognosis of glioblastoma. Our findings highlight Mo-TAM diversity and spatial niche-steered Mo-TAM reprogramming in diffuse gliomas and indicate potential therapeutics targeting Hypoxia-TAM to normalize tumor vasculature.

Biomarkers Improve Diagnostics of Sepsis in Adult Patients With Suspected Organ Dysfunction Based on the Quick Sepsis-Related Organ Failure Assessment (qSOFA) Score in the Emergency Department.

OBJECTIVES: Consensus regarding biomarkers for detection of infection-related organ dysfunction in the emergency department is lacking. We aimed to identify and validate biomarkers that could improve risk prediction for overt or incipient organ dysfunction when added to quick Sepsis-related Organ Failure Assessment (qSOFA) as a screening tool. DESIGN: In a large prospective multicenter cohort of adult patients presenting to the emergency department with a qSOFA score greater than or equal to 1, admission plasma levels of C-reactive protein, procalcitonin, adrenomedullin (either bioavailable adrenomedullin or midregional fragment of proadrenomedullin), proenkephalin, and dipeptidyl peptidase 3 were assessed. Least absolute shrinkage and selection operator regression was applied to assess the impact of these biomarkers alone or in combination to detect the primary endpoint of prediction of sepsis within 96 hours of admission. SETTING: Three tertiary emergency departments at German University Hospitals (Jena University Hospital and two sites of the Charité University Hospital, Berlin). PATIENTS: One thousand four hundred seventy-seven adult patients presenting with suspected organ dysfunction based on qSOFA score greater than or equal to 1. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The cohort was of moderate severity with 81% presenting with qSOFA = 1; 29.2% of these patients developed sepsis. Procalcitonin outperformed all other biomarkers regarding the primary endpoint (area under the curve for receiver operating characteristic [AUC-ROC], 0.86 [0.79-0.93]). Adding other biomarkers failed to further improve the AUC-ROC for the primary endpoint; however, they improved the model regarding several secondary endpoints, such as mortality, need for vasopressors, or dialysis. Addition of procalcitonin with a cutoff level of 0.25 ng/mL improved net (re)classification by 35.2% compared with qSOFA alone, with positive and negative predictive values of 60.7% and 88.7%, respectively. CONCLUSIONS: Biomarkers of infection and organ dysfunction, most notably procalcitonin, substantially improve early prediction of sepsis with added value to qSOFA alone as a simple screening tool on emergency department admission.

Bioactive adrenomedullin and interleukin-6 in COVID-19: potential biomarkers of acute kidney injury and critical illness.

BACKGROUND: The aim of this study was to investigate whether bioactive adrenomedullin (bio-ADM) and interleukin-6 (IL-6) are related to acute kidney injury (AKI) and severe illness in COVID-19 patients. METHODS: 153 patients with COVID-19 admitted to the emergency department (ED) were included. Blood samples were collected from each patient at admission. Bio-ADM and IL-6, as well as DPP3 and routinely measured markers were evaluated regarding the endpoints AKI (22/128 hospitalized patients) and a composite endpoint of admission to intensive care unit and/or in-hospital death (n = 26/153 patients). RESULTS: Bio-ADM and IL-6 were significantly elevated in COVID-19 patients with AKI compared to COVID-19 patients without AKI (each p < 0.001). According to ROC analyses IL-6 and bio-ADM had the largest AUC (0.84 and 0.81) regarding the detection of AKI. Furthermore, bio-ADM and IL-6 were significantly elevated in COVID-19 patients reaching the composite endpoint (each p < 0.001). Regarding the composite endpoint ROC analysis showed an AUC of 0.89 for IL-6 and 0.83 for bio-ADM in COVID-19 patients. In the multivariable logistic model bio-ADM and IL-6 presented as independent significant predictors regarding both endpoints AKI and the composite endpoint in COVID-19 patients (as well as creatinine regarding the composite endpoint; each p < 0.05), opposite to leukocytes, C-reactive protein (CRP) and dipeptidyl peptidase 3 (DPP3; each p = n.s.). CONCLUSION: Elevated levels of bio-ADM and IL-6 are associated with AKI and critical illness in patients with COVID-19. Therefore, both biomarkers may be potential tools in risk stratification in COVID-19 patients at presentation in the ED.

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 ß-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.