Adrenomedullin, a multifunctional regulatory peptide

Cardiac and intestinal tissue conduct developmental and reparative processes in response to lymphangiocrine signaling

Lymphatic vessels conduct a diverse range of activities to sustain the integrity of surrounding tissue. Besides facilitating the movement of lymph and its associated factors, lymphatic vessels are capable of producing tissue-specific responses to changes within their microenvironment. Lymphatic endothelial cells (LECs) secrete paracrine signals that bind to neighboring cell-receptors, commencing an intracellular signaling cascade that preludes modifications to the organ tissue's structure and function. While the lymphangiocrine factors and the molecular and cellular mechanisms themselves are specific to the organ tissue, the crosstalk action between LECs and adjacent cells has been highlighted as a commonality in augmenting tissue regeneration within animal models of cardiac and intestinal disease. Lymphangiocrine secretions have been owed for subsequent improvements in organ function by optimizing the clearance of excess tissue fluid and immune cells and stimulating favorable tissue growth, whereas perturbations in lymphatic performance bring about the opposite. Newly published landmark studies have filled gaps in our understanding of cardiac and intestinal maintenance by revealing key players for lymphangiocrine processes. Here, we will expand upon those findings and review the nature of lymphangiocrine factors in the heart and intestine, emphasizing its involvement within an interconnected network that supports daily homeostasis and self-renewal following injury.

Neuroendocrine response to diclofenac in healthy subjects: a pilot study

PURPOSE

The precise effects of non-steroidal anti-inflammatory drugs on the neuroendocrine hydro-electrolytic regulation are not precisely understood. The aim of this pilot study was to evaluate, in healthy subjects, the neuroendocrine response of the antidiuretic system to intravenous diclofenac infusion.

METHODS

For this single-blinded, cross-over study, we recruited 12 healthy subjects (50% women). Test sessions were divided into three observation times (pre-test; test; 48 h post-test), which were repeated equally on two different occasions, with the administration of diclofenac (75 mg in saline solution 0.9% 100 cc) on 1 day, or placebo (saline solution 0.9% 100 cc) on another day. The night before the test the subjects were asked to collect a salivary cortisol and cortisone sample, which was repeated on the night of the procedure session. Serial urine and blood samples were collected on the test day (for osmolality, electrolytes, ACTH, cortisol, copeptin, MR-proADM, MR-proANP; the last three represent more stable and analytically reliable molecules than their respective active peptides). Moreover, the subjects were evaluated with the bioimpedance vector analysis (BIVA) before and after the test. Forty-eight hours after the end of the procedure urine sodium, urine potassium, urine osmolality, serum sodium and copeptin were revaluated together with BIVA.

RESULTS

No significant changes in circulating hormone levels were observed; anyway, 48 h after diclofenac, BIVA showed a significant water retention (p < 0.00001), especially in extracellular fluid (ECF) (16.47 ± 1.65 vs 15.67 ± 1.84, p < 0.001). Salivary cortisol and cortisone tended to increase only the night after placebo administration (p = 0.054 cortisol; p = 0.021 cortisone).

CONCLUSION

Diclofenac resulted in an increased ECF at 48 h, but this phenomenon seems to be associated with a greater renal sensibility to the action of vasopressin rather than with an increase in its secretion. Moreover, a partial inhibitory effect on cortisol secretion can be hypothesized.

Systematic review with meta-analysis of mid-regional pro-adrenomedullin (MR-proadm) as a prognostic marker in Covid-19-hospitalized patients

BACKGROUND

Mid-regional pro-adrenomedullin (MR-proADM) is useful for risk stratification in patients with sepsis and respiratory infections. The study's purpose was to assess the available data and determine the association between MR-proADM levels and mortality in COVID-19 participants.

METHODS

A comprehensive literature search of medical electronic databases was performed including PubMed, Web of Science, Scopus, Cochrane, and grey literature for relevant data published from 1 January 2020, to 20 November 2022. Mean differences (MD) with 95% confidence intervals (CI) were calculated.

RESULTS

Fourteen studies reported MR-proADM levels in survivors vs. non-survivors of COVID-19 patients. Pooled analysis showed that MR-proADM level in the survivor group was 0.841 ± 0.295 nmol/L for patients who survive COVID-19, compared to 1.692 ± 0.761 nmol/L for non-survivors (MD = -0.78; 95%CI: -0.92 to -0.64; p < 0.001).

CONCLUSIONS

The main finding of this study is that mortality of COVID-19 is linked to MR-proADM levels, according to this meta-analysis. The use of MR-proADM might be extremely beneficial in triaging, assessing probable therapy escalation, predicting potential complications during therapy or significant clinical deterioration of patients, and avoiding admission which may not be necessary. Nevertheless, in order to confirm the obtained data, it is necessary to conduct large prospective studies that will address the potential diagnostic role of MR-proADM as a marker of COVID-19 severity.KEY MESSAGESSeverity of COVID-19 seems to be linked to MR-proADM levels and can be used as a potential marker for predicting a patient's clinical course.The use of MR-proADM might be beneficial in triaging, assessing probable therapy escalation, predicting potential complications during therapy or significant clinical deterioration of patients, and avoiding admission which may not be necessary.For patients with COVID-19, MR-proADM may be an excellent prognostic indicator because it is a marker of endothelial function that may predict the precise impact on the equilibrium between vascular relaxation and contraction and lowers platelet aggregation inhibitors, coagulation inhibitors, and fibrinolysis activators in favor of clotting factors.

Mid-Regional Proadrenomedullin in COVID-19-May It Act as a Predictor of Prolonged Cardiovascular Complications?

The rising prevalence of cardiovascular disease (CVD) and the impact of the SARS-CoV-2 pandemic have both led to increased mortality rates, affecting public health and the global economy. Therefore, it is essential to find accessible, non-invasive prognostic markers capable of identifying patients at high risk. One encouraging avenue of exploration is the potential of mid-regional proadrenomedullin (MR-proADM) as a biomarker in various health conditions, especially in the context of CVD and COVID-19. MR-proADM presents the ability to predict mortality, heart failure, and adverse outcomes in CVD, offering promise for improved risk assessment and treatment strategies. On the other hand, an elevated MR-proADM level is associated with disease severity and cytokine storms in patients with COVID-19, making it a predictive indicator for intensive care unit admissions and mortality rates. Moreover, MR-proADM may have relevance in long COVID, aiding in the risk assessment, triage, and monitoring of individuals at increased risk of developing prolonged cardiac issues. Our review explores the potential of MR-proADM as a predictor of enduring cardiovascular complications following COVID-19 infection.

Urinary Tract Infections: Renal Intercalated Cells Protect against Pathogens

Urinary tract infections affect more than 1 in 2 women during their lifetime. Among these, more than 10% of patients carry antibiotic-resistant bacterial strains, highlighting the urgent need to identify alternative treatments. While innate defense mechanisms are well-characterized in the lower urinary tract, it is becoming evident that the collecting duct (CD), the first renal segment encountered by invading uropathogenic bacteria, also contributes to bacterial clearance. However, the role of this segment is beginning to be understood. This review summarizes the current knowledge on CD intercalated cells in urinary tract bacterial clearance. Understanding the innate protective role of the uroepithelium and of the CD offers new opportunities for alternative therapeutic strategies.

Changes in mid-regional pro-adrenomedullin during treatment with sacubitril/valsartan

AIMS

Adrenomedullin is a vasodilatory peptide with a role in microcirculatory and endothelial homeostasis. Adrenomedullin is a substrate for neprilysin and may therefore play a role in beneficial effects of sacubitril/valsartan (Sac/Val) treatment.

METHODS AND RESULTS

Mid-regional pro-adrenomedullin (MR-proADM) was measured in 156 patients with heart failure with reduced ejection fraction (HFrEF) treated with Sac/Val and 264 patients with heart failure with preserved ejection fraction (HFpEF) randomized to treatment with Sac/Val or valsartan. Echocardiography and Kansas City Cardiomyopathy Questionnaire results were collected at baseline and after 6 and 12 months in the HFrEF cohort. Median (Q1-Q3) baseline MR-proADM concentrations were 0.80 (0.59-0.99) nmol/L in HFrEF and 0.88 (0.68-1.20) nmol/L in HFpEF. After 12 weeks of treatment with Sac/Val, MR-proADM increased by median 49% in HFrEF and 60% in HFpEF, while there were no significant changes in valsartan-treated patients (median 2%). Greater increases in MR-proADM were associated with higher Sac/Val doses. Changes in MR-proADM correlated weakly with changes in N-terminal pro-B-type natriuretic peptide, cardiac troponin T and urinary cyclic guanosine monophosphate. Increases in MR-proADM were associated with decreases in blood pressure, but not significantly associated with changes in echocardiographic parameters or health status.

CONCLUSIONS

MR-proAD concentrations rise substantially following treatment with Sac/Val, in contrast to no change from valsartan. Change in MR-proADM from neprilysin inhibition did not correlate with improvements in cardiac structure and function or health status. More data are needed regarding the role of adrenomedullin and its related peptides in the treatment of heart failure.

CLINICAL TRIAL REGISTRATION

PROVE-HF ClinicalTrials.gov Identifier: NCT02887183, PARAMOUNT ClinicalTrials.gov Identifier: NCT00887588.

CGRP physiology, pharmacology, and therapeutic targets: migraine and beyond

Calcitonin gene-related peptide (CGRP) is a neuropeptide with diverse physiological functions. Its two isoforms (α and β) are widely expressed throughout the body in sensory neurons as well as in other cell types, such as motor neurons and neuroendocrine cells. CGRP acts via at least two G protein-coupled receptors that form unusual complexes with receptor activity-modifying proteins. These are the CGRP receptor and the AMY1 receptor; in rodents, additional receptors come into play. Although CGRP is known to produce many effects, the precise molecular identity of the receptor(s) that mediates CGRP effects is seldom clear. Despite the many enigmas still in CGRP biology, therapeutics that target the CGRP axis to treat or prevent migraine are a bench-to-bedside success story. This review provides a contextual background on the regulation and sites of CGRP expression and CGRP receptor pharmacology. The physiological actions of CGRP in the nervous system are discussed, along with updates on CGRP actions in the cardiovascular, pulmonary, gastrointestinal, immune, hematopoietic, and reproductive systems and metabolic effects of CGRP in muscle and adipose tissues. We cover how CGRP in these systems is associated with disease states, most notably migraine. In this context, we discuss how CGRP actions in both the peripheral and central nervous systems provide a basis for therapeutic targeting of CGRP in migraine. Finally, we highlight potentially fertile ground for the development of additional therapeutics and combinatorial strategies that could be designed to modulate CGRP signaling for migraine and other diseases.

Calcitonin Gene-Related Peptide and Adrenomedullin Levels During Ictal and Interictal Periods in Patients With Migraine

Background Peptides related to calcitonin gene-related peptide (CGRP) have been suggested to have a role in migraine. Adrenomedullin (AM) might be a candidate molecule because it is related to pain pathways in the peripheral and central nervous systems and uses the same receptors as CGRP. Methodology In this study, we examined the serum CGRP and AM levels during unprovoked ictal and interictal periods of 30 migraine patients as well as 25 healthy controls. Another focus of this study was on the association of CGRP and AM levels with clinical features. Results Mean serum AM levels were 15.80 pg/mL (11.91-21.43 pg/mL) in the ictal and 15.85 pg/mL (12.25-19.29 pg/mL) in the interictal periods in the migraine group and 13.36 pg/mL (10.84-17.18 pg/mL) in the control group. Mean serum CGRP levels were 2.93 pg/mL (2.45-3.90 pg/mL) in the ictal and 3.25 pg/mL (2.85-4.67 pg/mL) in the interictal periods in the migraine group and 3.03 pg/mL (2.48-3.80 pg/mL) in the control group. There were no statistical differences between ictal and/or interictal AM and CGRP levels (p = 0.558 and p = 0.054, respectively) which were also comparable with the results of the control group (p = 0.230, p = 0.295, p = 0.987, p = 0.139, respectively). Ictal serum CGRP and/or AM levels did not correlate with any of the reported clinical features. Conclusions Serum AM and CGRP levels are similar in interictal and unprovoked ictal periods in migraine patients and as well in controls. These results do not indicate that these molecules do not have a role in migraine pathophysiology. Considering the broad mechanisms of action of peptides in the CGRP family, further studies are needed in larger cohorts.

Gel-forming antagonist provides a lasting effect on CGRP-induced vasodilation

Migraine affects ∼15% of the adult population, and the standard treatment includes the use of triptans, ergotamines, and analgesics. Recently, CGRP and its receptor, the CLR/RAMP1 receptor complex, have been targeted for migraine treatment due to their critical roles in mediating migraine headaches. The effort has led to the approval of several anti-CGRP antibodies for chronic migraine treatment. However, many patients still suffer continuous struggles with migraine, perhaps due to the limited ability of anti-CGRP therapeutics to fully reduce CGRP levels or reach target cells. An alternative anti-CGRP strategy may help address the medical need of patients who do not respond to existing therapeutics. By serendipity, we have recently found that several chimeric adrenomedullin/adrenomedullin 2 peptides are potent CLR/RAMP receptor antagonists and self-assemble to form liquid gels. Among these analogs, the ADE651 analog, which potently inhibits CLR/RAMP1 receptor signaling, forms gels at a 6-20% level. Screening of ADE651 variants indicated that residues at the junctional region of this chimeric peptide are important for gaining the gel-forming capability. Gel-formation significantly slowed the passage of ADE651 molecules through Centricon filters. Consistently, subcutaneous injection of ADE651 gel in rats led to the sustained presence of ADE651 in circulation for >1 week. In addition, analysis of vascular blood flow in rat hindlimbs showed ADE651 significantly reduces CGRP-induced vasodilation. Because gel-forming antagonists could have direct and sustained access to target cells, ADE651 and related antagonists for CLR/RAMP receptors may represent promising candidates for targeting CGRP- and/or adrenomedullin-mediated headaches in migraine patients.

Adrenomedullin Secreted by Melanoma Cells Promotes Melanoma Tumor Growth through Angiogenesis and Lymphangiogenesis

INTRODUCTION

Metastatic melanoma is an aggressive tumor and can constitute a real therapeutic challenge despite the significant progress achieved with targeted therapies and immunotherapies, thus highlighting the need for the identification of new therapeutic targets. Adrenomedullin (AM) is a peptide with significant expression in multiple types of tumors and is multifunctional. AM impacts angiogenesis and tumor growth and binds to calcitonin receptor-like receptor/receptor activity-modifying protein 2 or 3 (CLR/RAMP2; CLR/RAMP3).

METHODS

In vitro and in vivo studies were performed to determine the functional role of AM in melanoma growth and tumor-associated angiogenesis and lymphangiogenesis.

RESULTS

In this study, AM and AM receptors were immunohistochemically localized in the tumoral compartment of melanoma tissue, suggesting that the AM system plays a role in melanoma growth. We used A375, SK-MEL-28, and MeWo cells, for which we demonstrate an expression of AM and its receptors; hypoxia induces the expression of AM in melanoma cells. The proliferation of A375 and SK-MEL-28 cells is decreased by anti-AM antibody (αAM) and anti-AMR antibodies (αAMR), supporting the fact that AM may function as a potent autocrine/paracrine growth factor for melanoma cells. Furthermore, migration and invasion of melanoma cells increased after treatment with AM and decreased after treatment with αAMR, thus indicating that melanoma cells are regulated by AM. Systemic administration of αAMR reduced neovascularization of in vivo Matrigel plugs containing melanoma cells, as demonstrated by reduced numbers of vessel structures, which suggests that AM is one of the melanoma cells-derived factors responsible for endothelial cell-like and pericyte recruitment in the construction of neovascularization. In vivo, αAMR therapy blocked angiogenesis and lymphangiogenesis and decreased proliferation in MeWo xenografts, thereby resulting in tumor regression. Histological examination of αAMR-treated tumors showed evidence of the disruption of tumor vascularity, with depletion of vascular endothelial cells and a significant decrease in lymphatic endothelial cells.

CONCLUSIONS

The expression of AM by melanoma cells promotes tumor growth and neovascularization by supplying/amplifying signals for neoangiogenesis and lymphangiogenesis.

Endothelial-mesenchymal transition induced by metastatic 4T1 breast cancer cells in pulmonary endothelium in aged mice

Ageing is a major risk factor for cancer metastasis but the underlying mechanisms remain unclear. Here, we characterised ageing effects on cancer-induced endothelial-mesenchymal transition (EndMT) in the pulmonary circulation of female BALB/c mice in a metastatic 4T1 breast cancer model. The effect of intravenously injected 4T1 cells on pulmonary endothelium, pulmonary metastasis, lung tissue architecture, and systemic endothelium was compared between 40-week-old and 20-week-old mice. The 40-week-old mice showed features of ongoing EndMT in their lungs before 4T1 breast cancer cell injection. Moreover, they had preexisting endothelial dysfunction in the aorta detected by in vivo magnetic resonance imaging (MRI) compared to 20-week-old mice. The injection of 4T1 breast cancer cells into 40-week-old mice resulted in rapid EndMT progression in their lungs. In contrast, injection of 4T1 breast cancer cells into 20-week-old mice resulted in initiation and less pronounced EndMT progression. Although the number of metastases did not differ significantly between 20-week-old and 40-week-old mice, the lungs of older mice displayed altered lung tissue architecture and biochemical content, reflected in higher Amide II/Amide I ratio, higher fibronectin levels, and hypoxia-inducible factor 1 subunit alpha (HIF1α) levels as well as lower nitric oxide (NO) production. Our results indicate that age-dependent pre-existing endothelial dysfunction in the pulmonary endothelium of 40-week-old mice predisposed them to rapid EndMT progression in the presence of circulating 4T1 breast cancer cells what might contribute to a more severe metastatic breast cancer phenotype in these ageing mice compared to younger mice.

Effects of Adrenomedullin on Atrial Electrophysiology and Pulmonary Vein Arrhythmogenesis

Adrenomedullin, a peptide with vasodilatory, natriuretic, and diuretic effects, may be a novel agent for treating heart failure. Heart failure is associated with an increased risk of atrial fibrillation (AF), but the effects of adrenomedullin on atrial arrhythmogenesis remain unclear. This study investigated whether adrenomedullin modulates the electrophysiology of the atria (AF substrate) or pulmonary vein (PV; AF trigger) arrhythmogenesis. Conventional microelectrode or whole-cell patch clamps were used to study the effects of adrenomedullin (10, 30, and 100 pg/mL) on the electrical activity, mechanical response, and ionic currents of isolated rabbit PV and sinoatrial node tissue preparations and single PV cardiomyocytes. At 30 and 100 pg/mL, adrenomedullin significantly reduced the spontaneous beating rate of the PVs from 2.0 ± 0.4 to 1.3 ± 0.5 and 1.1 ± 0.5 Hz (reductions of 32.9% ± 7.1% and 44.9 ± 8.4%), respectively, and reduced PV diastolic tension by 12.8% ± 4.1% and 14.5% ± 4.1%, respectively. By contrast, adrenomedullin did not affect sinoatrial node beating. In the presence of L-NAME (a nitric oxide synthesis inhibitor, 100 μM), adrenomedullin (30 pg/mL) did not affect the spontaneous beating rate or diastolic tension of the PVs. In the single-cell experiments, adrenomedullin (30 pg/mL) significantly reduced the L-type calcium current (I_Ca-L) and reverse-mode current of the sodium-calcium exchanger (NCX). Adrenomedullin reduces spontaneous PV activity and PV diastolic tension by reducing I_Ca-L and NCX current and thus may be useful for treating atrial tachyarrhythmia.

Suppression of CCL2 angiocrine function by adrenomedullin promotes tumor growth

Within the tumor microenvironment, tumor cells and endothelial cells regulate each other. While tumor cells induce angiogenic responses in endothelial cells, endothelial cells release angiocrine factors, which act on tumor cells and other stromal cells. We report that tumor cell-derived adrenomedullin has a pro-angiogenic as well as a direct tumor-promoting effect, and that endothelium-derived CC chemokine ligand 2 (CCL2) suppresses adrenomedullin-induced tumor cell proliferation. Loss of the endothelial adrenomedullin receptor CALCRL or of the G-protein Gs reduced endothelial proliferation. Surprisingly, tumor cell proliferation was also reduced after endothelial deletion of CALCRL or Gs. We identified CCL2 as a critical angiocrine factor whose formation is inhibited by adrenomedullin. Furthermore, CCL2 inhibited adrenomedullin formation in tumor cells through its receptor CCR2. Consistently, loss of endothelial CCL2 or tumor cell CCR2 normalized the reduced tumor growth seen in mice lacking endothelial CALCRL or Gs. Our findings show tumor-promoting roles of adrenomedullin and identify CCL2 as an angiocrine factor controlling adrenomedullin formation by tumor cells.

Relation between Mid-Regional Pro-Adrenomedullin in Patients with Chronic Heart Failure and the Dose of Diuretics in 2-Year Follow-Up-Data from FAR NHL Registry

Background and Objectives: The aim of this paper is to evaluate the impact of humoral substance mid-regional pro-adrenomedullin (MR-proADM) on the two-year survival of patients with chronic heart failure and relate it to the dosage of furosemide. Materials and Methods: The data is taken from the stable systolic heart failure (EF < 50%) FAR NHL registry (FARmacology and NeuroHumoraL activation). The primary endpoint at two-year follow-up was death, heart transplantation, or LVAD implantation. Results: A total of 1088 patients were enrolled in the FAR NHL registry; MR-proADM levels were available for 569 of them. The mean age was 65 years, and 81% were male. The aetiology of HF was ischemic heart disease in 53% and dilated cardiomyopathy in 41% of patients. The mean EF was 31 ± 9%. Statistically significant differences (p < 0.001) were obtained in several parameters: patients with higher MR-proADM levels were older, rated higher in NYHA class, suffered more often from lower limb oedema, and had more comorbidities such as hypertension, atrial fibrillation, diabetes, and renal impairment. MR-proADM level was related to furosemide dose. Patients taking higher doses of diuretics had higher MR-proADM levels. The mean MR-proADM level without furosemide (n = 122) was 0.62 (±0.55) nmol/L, with low dose (n = 113) 1−39 mg/day was 0.67 (±0.30) nmol/L, with mid dose (n = 202) 40−79 mg/day was 0.72 (±0.34) nmol/L, with high dose (n = 58) 80−119 mg/day was 0.85 (±0.40) nmol/L, and with maximum dose (n = 74) ≥120 mg/day was 1.07 (±0.76) nmol/L, p < 0.001. Patients with higher MR-proADM levels were more likely to achieve the primary endpoint at a two-year follow-up (p < 0.001) according to multivariant analysis. Conclusions: Elevated plasma MR-proADM levels in patients with chronic heart failure are associated with an increased risk of death and hospitalization. Higher MR-proADM levels in combination with increased use of loop diuretics reflect residual congestion and are associated with a higher risk of severe disease progression.

Plasma mid-regional pro-adrenomedullin: A biomarker of the ischemic penumbra in hyperacute stroke

Reperfusion therapy has improved the outcomes of ischemic stroke but also emphasized the importance of ischemic penumbra. However, blood biomarkers are currently unavailable for this region. Adrenomedullin (ADM) is a neuroprotective peptide, secreted in a compensatory response to brain ischemia. We thus investigated whether an increase in mid-regional pro-ADM (MR-proADM), a stable peptide fragment of the ADM precursor, could act as a biomarker by predicting the ischemic penumbra in hyperacute ischemic stroke (HAIS). We prospectively enrolled consecutive HAIS patients (n = 119; median age, 77 years; male, 59.7%) admitted to our institutes from July 2017 to March 2019 and evaluated plasma MR-proADM levels within 4.5 h of onset. MR-proADM levels in HAIS were compared to healthy controls (n = 1298; median age, 58 years; male, 33.2%) in the Japan Multi-Institutional Collaborative Cohort Study from 2013 to 2017. Furthermore, we evaluated whether MR-proADM levels were associated with the penumbra estimated by clinical-diffusion mismatch (CDM) (National Institute of Health Stroke Scale [NIHSS] ≥8, diffusion ischemic core volume ≤25 ml), or magnetic resonance angiography-diffusion-weighted imaging mismatch (MDM) (NIHSS ≥5, a proximal vessel occlusion with core volume ≤25 ml, or a proximal vessel stenosis/distal vessel occlusion with core volume ≤15 ml). In a case-control study, multivariate logistic analysis showed a significant association between HAIS and MR-proADM ≥0.54 nmol/L (adjusted odds ratio, 7.92 [95% CI, 4.17-15.02], p < 0.001). Though MR-proADM levels in HAIS did not correlate with the ischemic core volume (r_s  = 0.09, p = 0.348), they were higher in HAIS with CDM (n = 34; 0.81 vs. 0.61 nmol/L, p < 0.001) or MDM (n = 26; 0.83 vs. 0.62 nmol/L, p = 0.002). These differences remained significant after adjusting baseline factors (adjusted odds ratio, 4.06 [95% CI, 1.31-12.55], p = 0.015 and 4.65 [1.35-16.11], p = 0.015, respectively). Plasma MR-proADM is elevated in HAIS, especially in those with a substantial penumbra, suggesting potential as a blood biomarker in this region.

Adrenomedullin: Not Just Another Gastrointestinal Peptide

Adrenomedullin (AM) and proadrenomedullin N-terminal 20 peptide (PAMP) are two bioactive peptides derived from the same precursor with several biological functions including vasodilation, angiogenesis, or anti-inflammation, among others. AM and PAMP are widely expressed throughout the gastrointestinal (GI) tract where they behave as GI hormones, regulating numerous physiological processes such as gastric emptying, gastric acid release, insulin secretion, bowel movements, or intestinal barrier function. Furthermore, it has been recently demonstrated that AM/PAMP have an impact on gut microbiome composition, inhibiting the growth of bacteria related with disease and increasing the number of beneficial bacteria such as Lactobacillus or Bifidobacterium. Due to their wide functions in the GI tract, AM and PAMP are involved in several digestive pathologies such as peptic ulcer, diabetes, colon cancer, or inflammatory bowel disease (IBD). AM is a key protective factor in IBD onset and development, as it regulates cytokine production in the intestinal mucosa, improves vascular and lymphatic regeneration and function and mucosal epithelial repair, and promotes a beneficial gut microbiome composition. AM and PAMP are relevant GI hormones that can be targeted to develop novel therapeutic agents for IBD, other GI disorders, or microbiome-related pathologies.

Oocyte-specific disruption of adrenomedullin 2 gene enhances ovarian follicle growth after superovulation

BACKGROUND

Adrenomedullin 2 (ADM2), adrenomedullin (ADM), and calcitonin gene-related peptides (α- and β-CGRPs) signal through heterodimeric calcitonin receptor-like receptor/receptor activity-modifying protein 1, 2 and 3 (CLR/RAMP1, 2 and 3) complexes. These peptides are important regulators of neurotransmission, vasotone, cardiovascular development, and metabolic homeostasis. In rodents, ADM is essential for regulating embryo implantation, fetal-placental development, and hemodynamic adaptation during pregnancy. On the other hand, ADM2 was shown to affect vascular lumen enlargement, and cumulus cell-oocyte complex (COC) communication in rodent and bovine ovarian follicles. To investigate whether oocyte-derived ADM2 plays a physiological role in regulating ovarian folliculogenesis, we generated mice with oocyte-specific disruption of the Adm2 gene using a LoxP-flanked Adm2 transgene (Adm2 loxP/loxP) and crossed them with Zp3-Cre mice which carry a zona pellucida 3 (Zp3) promoter-Cre recombinase transgene.

RESULTS

While heterozygous Adm2 +/-/Zp3-Cre and homozygous Adm2 -/-/Zp3-Cre mice were fertile, Adm2 disruption in oocytes significantly increased the number of ovulated oocytes following a superovulation treatment. Oocyte-specific Adm2 disruption also significantly impaired the developmental capacity of fertilized eggs and decreased the size of the corpus luteum following superovulation, perhaps due to a reduction of ovarian cyclin D2-associated signaling.

CONCLUSIONS

The disruption of intrafollicular ADM2 signaling leads to follicular dysfunction. These data suggested that oocyte-derived ADM2 plays a facilitative role in the regulation of hormonal response and follicle growth independent of the closely related ADM and CGRP peptides, albeit in a subtle manner.

Diagnosis of neonatal sepsis: the past, present and future

Sepsis remains a significant cause of neonatal mortality and morbidity, especially in low- and middle-income countries. Neonatal sepsis presents with nonspecific signs and symptoms that necessitate tests to confirm the diagnosis. Early and accurate diagnosis of infection will improve clinical outcomes and decrease the overuse of antibiotics. Current diagnostic methods rely on conventional culture methods, which is time-consuming, and may delay critical therapeutic decisions. Nonculture-based techniques including molecular methods and mass spectrometry may overcome some of the limitations seen with culture-based techniques. Biomarkers including hematological indices, cell adhesion molecules, interleukins, and acute-phase reactants have been used for the diagnosis of neonatal sepsis. In this review, we examine past and current microbiological techniques, hematological indices, and inflammatory biomarkers that may aid sepsis diagnosis. The search for an ideal biomarker that has adequate diagnostic accuracy early in sepsis is still ongoing. We discuss promising strategies for the future that are being developed and tested that may help us diagnose sepsis early and improve clinical outcomes. IMPACT: Reviews the clinical relevance of currently available diagnostic tests for sepsis. Summarizes the diagnostic accuracy of novel biomarkers for neonatal sepsis. Outlines future strategies including the use of omics technology, personalized medicine, and point of care tests.

Biomarkers and Fever in Children with Cancer: Kinetics and Levels According to Final Diagnosis

We investigated the kinetics of CRP, PCT, IL-6 and MR-proADM in a cohort of consecutive febrile patients with cancer in order to test the hypothesis that higher plasma concentrations and the absence of a rapid decrease in peak values would be associated with disease severity. (1) Method: A prospective descriptive and analytical study of patients with cancer and fever (≤18 years of age) at a University Hospital was carried out between January 2018 and December 2019. Information collected: sex, age, diagnosis, date and symptoms at diagnosis and medical history. The episodes were classified into three groups: bacterial infection, non-bacterial infection and systemic inflammatory response syndrome (SIRS). (2) Results: One hundred and thirty-four episodes were included. Bacterial infection criteria were met in 38 episodes. Biomarkers were measured at four different points: baseline, at 12–24 h, at 25–48 h and at 49–72 h. All the biomarkers evaluated decreased after the peak level was reached. IL-6 and MR-proADM showed a trend towards higher levels in the SIRS group although this rise was statistically significant only for IL-6 (p < 0.005). Bacterial infections more frequently presented values of PCT above the cut-off point (>0.5 ng/mL) at 12–24 h. (3) Conclusion: In our experience, IL-6 kinetics is faster than PCT kinetics and both are faster than CRP in patients with fever and cancer who present a good outcome. Patients with a good evolution show a rapid increase and decrease of PCT and particularly of IL-6 levels.

Role of the Tyrosine Phosphatase SHP-2 in Mediating Adrenomedullin Proangiogenic Activity in Solid Tumors

VE-cadherin is an essential adhesion molecule in endothelial adherens junctions, and the integrity of these complexes is thought to be regulated by VE-cadherin tyrosine phosphorylation. We have previously shown that adrenomedullin (AM) blockade correlates with elevated levels of phosphorylated VE-cadherin (pVE-cadherin^Y731) in endothelial cells, associated with impaired barrier function and a persistent increase in vascular endothelial cell permeability. However, the mechanism underlying this effect is unknown. In this article, we demonstrate that the AM-mediated dephosphorylation of pVE-cadherin^Y731 takes place through activation of the tyrosine phosphatase SHP-2, as judged by the rise of its active fraction phosphorylated at tyrosine 542 (pSHP-2^Y542) in HUVECs and glioblastoma-derived-endothelial cells. Both pre-incubation of HUVECs with SHP-2 inhibitors NSC-87877 and SHP099 and SHP-2 silencing hindered AM-induced dephosphorylation of pVE-cadherin^Y731 in a dose dependent-manner, showing the role of SHP-2 in the regulation of endothelial cell contacts. Furthermore, SHP-2 inhibition impaired AM-induced HUVECs differentiation into cord-like structures in vitro and impeded AM-induced neovascularization in in vivo Matrigel plugs bioassays. Subcutaneously transplanted U87-glioma tumor xenograft mice treated with AM-receptors-blocking antibodies showed a decrease in pSHP-2^Y542 associated with VE-cadherin in nascent tumor vasculature when compared to control IgG-treated xenografts.

Our findings show that AM acts on VE-cadherin dynamics through pSHP-2^Y542 to finally modulate cell-cell junctions in the angiogenesis process, thereby promoting a stable and functional tumor vasculature.

Prevention of vascular calcification by the endogenous chromogranin A-derived mediator that inhibits osteogenic transdifferentiation

The adrenal glands participate in cardiovascular (CV) physiology and the pathophysiology of CV diseases through their effects on sodium and water metabolism, vascular tone and cardiac function. In the present study, we identified a new adrenal compound controlling mesenchymal cell differentiation that regulates osteoblastic differentiation in the context of vascular calcification. This peptide was named the “calcification blocking factor” (CBF) due to its protective effect against vascular calcification and is released from chromogranin A via enzymatic cleavage by calpain 1 and kallikrein. CBF reduced the calcium content of cells and thoracic aortic rings under calcifying culture conditions, as well as in aortas from animals treated with vitamin D and nicotine (VDN animals). Furthermore, CBF prevented vascular smooth muscle cell (VSMC) transdifferentiation into osteoblast-like cells within the vascular wall via the sodium-dependent phosphate transporter PIT-1 and by inhibition of NF-κB activation and the subsequent BMP2/p-SMAD pathway. Pulse pressure, a marker of arterial stiffness, was significantly decreased in VDN animals treated with CBF. In line with our preclinical data, CBF concentration is significantly reduced in diseases characterized by increased calcification, as shown in patients with chronic kidney disease. In preparation for clinical translation, the active site of the native 19-AS long native CBF was identified as EGQEEEED. In conclusion, we have identified the new peptide CBF, which is secreted from the adrenal glands and might prevent vascular calcification by inhibition of osteogenic transdifferentiation. The anti-calcific effects of CBF and short active site may therefore promote the development of new tools for the prevention and/or treatment of vascular calcification.

CRIF1 deficiency suppresses endothelial cell migration via upregulation of RhoGDI2

Rho GDP-dissociation inhibitor (RhoGDI), a downregulator of Rho family GTPases, prevents nucleotide exchange and membrane association. It is responsible for the activation of Rho GTPases, which regulate a variety of cellular processes, such as migration. Although RhoGDI2 has been identified as a tumor suppressor gene involved in cellular migration and invasion, little is known about its role in vascular endothelial cell (EC) migration. CR6-interacting factor 1 (CRIF1) is a CR6/GADD45-interacting protein with important mitochondrial functions and regulation of cell growth. We examined the expression of RhoGDI2 in CRIF1-deficient human umbilical vein endothelial cells (HUVECs) and its role in cell migration. Expression of RhoGDI2 was found to be considerably higher in CRIF1-deficient HUVECs along with suppression of cell migration. Moreover, the phosphorylation levels of Akt and CREB were decreased in CRIF1-silenced cells. The Akt-CREB signaling pathway was implicated in the changes in endothelial cell migration caused by CRIF1 downregulation. In addition to RhoGDI2, we identified another factor that promotes migration and invasion of ECs. Adrenomedullin2 (ADM2) is an autocrine/paracrine factor that regulates vascular tone and other vascular functions. Endogenous ADM2 levels were elevated in CRIF1-silenced HUVECs with no effect on cell migration. However, siRNA-mediated depletion of RhoGDI2 or exogenous ADM2 administration significantly restored cell migration via the Akt-CREB signaling pathway. In conclusion, RhoGDI2 and ADM2 play important roles in the migration of CRIF1-deficient endothelial cells.

Novel Chemically Modified Curcumin (CMC) Analogs Exhibit Anti-Melanogenic Activity in Primary Human Melanocytes

Hyperpigmentation is a dermatological condition characterized by the overaccumulation and/or oversecretion of melanin pigment. The efficacy of curcumin as an anti-melanogenic therapeutic has been recognized, but the poor stability and solubility that have limited its use have inspired the synthesis of novel curcumin analogs. We have previously reported on comparisons of the anti-melanogenic activity of four novel chemically modified curcumin (CMC) analogs, CMC2.14, CMC2.5, CMC2.23 and CMC2.24, with that of parent curcumin (PC), using a B16F10 mouse melanoma cell model, and we have investigated mechanisms of inhibition. In the current study, we have extended our findings using normal human melanocytes from a darkly pigmented donor (HEMn-DP) and we have begun to study aspects of melanosome export to human keratinocytes. Our results showed that all the CMCs downregulated the protein levels of melanogenic paracrine mediators, endothelin-1 (ET-1) and adrenomedullin (ADM) in HaCaT cells and suppressed the phagocytosis of FluoSphere beads that are considered to be melanosome mimics. All the three CMCs were similarly potent (except CMC2.14, which was highly cytotoxic) in inhibiting melanin production; furthermore, they suppressed dendricity in HEMn-DP cells. CMC2.24 and CMC2.23 robustly suppressed cellular tyrosinase activity but did not alter tyrosinase protein levels, while CMC2.5 did not suppress tyrosinase activity but significantly downregulated tyrosinase protein levels, indicative of a distinctive mode of action for the two structurally related CMCs. Moreover, HEMn-DP cells treated with CMC2.24 or CMC2.23 partially recovered their suppressed tyrosinase activity after cessation of the treatment. All the three CMCs were nontoxic to human dermal fibroblasts while PC was highly cytotoxic. Our results provide a proof-of-principle for the novel use of the CMCs for skin depigmentation, since at low concentrations, ranging from 5 to 25 µM, the CMCs (CMC2.24, CMC2.23 and CMC2.5) were more potent anti-melanogenic agents than PC and tetrahydrocurcumin (THC), both of which were ineffective at melanogenesis at similar doses, as tested in HEMn-DP cells (with PC being highly toxic in dermal fibroblasts and keratinocytes). Further studies to evaluate the efficacy of CMCs in human skin tissue and in vivo studies are warranted.

Adrenomedullin Expression Characterizes Leukemia Stem Cells and Associates With an Inflammatory Signature in Acute Myeloid Leukemia

Adrenomedullin (ADM) is a hypotensive and vasodilator peptide belonging to the calcitonin gene-related peptide family. It is secreted in vitro by endothelial cells and vascular smooth muscle cells, and is significantly upregulated by a number of stimuli. Moreover, ADM participates in the regulation of hematopoietic compartment, solid tumors and leukemias, such as acute myeloid leukemia (AML). To better characterize ADM involvement in AML pathogenesis, we investigated its expression during human hematopoiesis and in leukemic subsets, based on a morphological, cytogenetic and molecular characterization and in T cells from AML patients. In hematopoietic stem/progenitor cells and T lymphocytes from healthy subjects, ADM transcript was barely detectable. It was expressed at low levels by megakaryocytes and erythroblasts, while higher levels were measured in neutrophils, monocytes and plasma cells. Moreover, cells populating the hematopoietic niche, including mesenchymal stem cells, showed to express ADM. ADM was overexpressed in AML cells versus normal CD34+ cells and in the subset of leukemia compared with hematopoietic stem cells. In parallel, we detected a significant variation of ADM expression among cytogenetic subgroups, measuring the highest levels in inv(16)/t(16;16) or complex karyotype AML. According to the mutational status of AML-related genes, the analysis showed a lower expression of ADM in FLT3-ITD, NPM1-mutated AML and FLT3-ITD/NPM1-mutated cases compared with wild-type ones. Moreover, ADM expression had a negative impact on overall survival within the favorable risk class, while showing a potential positive impact within the subgroup receiving a not-intensive treatment. The expression of 135 genes involved in leukemogenesis, regulation of cell proliferation, ferroptosis, protection from apoptosis, HIF-1α signaling, JAK-STAT pathway, immune and inflammatory responses was correlated with ADM levels in the bone marrow cells of at least two AML cohorts. Moreover, ADM was upregulated in CD4+ T and CD8+ T cells from AML patients compared with healthy controls and some ADM co-expressed genes participate in a signature of immune tolerance that characterizes CD4+ T cells from leukemic patients. Overall, our study shows that ADM expression in AML associates with a stem cell phenotype, inflammatory signatures and genes related to immunosuppression, all factors that contribute to therapy resistance and disease relapse.

Prognostic Value of Bioactive Adrenomedullin in Critically Ill Patients with COVID-19 in Germany: An Observational Cohort Study

The coronavirus disease 2019 (COVID-19) pandemic has placed a significant burden on hospitals worldwide. Objective biomarkers for early risk stratification and clinical management are still lacking. The aim of this work was to determine whether bioactive adrenomedullin can assist in the risk stratification and clinical management of critically ill COVID-19 patients. Fifty-three patients with confirmed COVID-19 were included in this prospective observational cohort study between March and April 2020. Bioactive adrenomedullin (bio-ADM) plasma concentration was measured daily for seven days after admission. The prognostic value and clinical significance of bio-ADM plasma levels were evaluated for the severity of respiratory failure, the need for extracorporeal organ support and outcome (28-day mortality). Bio-ADM levels increased with the severity of acute respiratory distress syndrome (ARDS; p < 0.001) and were significantly elevated in invasively ventilated patients (p = 0.006) and patients in need of extracorporeal membrane oxygenation (p = 0.040) or renal replacement therapy (RRT; p < 0.001) compared to patients without these conditions. Non-survivors showed significantly higher bio-ADM levels than survivors (p = 0.010). Bio-ADM levels predicted 28-day mortality (C-index 0.72, 95% confidence interval 0.56–0.87, p < 0.001). Bio-ADM plasma levels correlate with disease severity, the need for extracorporeal organ assistance, and outcome, and highlight the promising value of bio-ADM in the early risk stratification and management of patients with COVID-19.

MR-proAdrenomedullin as a predictor of renal replacement therapy in a cohort of critically ill patients with COVID-19

BACKGROUND

About 20% of ICU patients with COVID-19 require renal replacement therapy (RRT). Mid-regional pro-adrenomedullin (MR-proADM) might be used for risk assessment. This study investigates MR-proADM for RRT prediction in ICU patients with COVID-19.

METHODS

We analysed data of consecutive patients with COVID-19, requiring ICU admission at a university hospital in Germany between March and September 2020. Clinical characteristics, details on AKI, and RRT were assessed. MR-proADM was measured on admission.

RESULTS

64 patients were included (49 (77%) males). Median age was 62.5y (54-73). 47 (73%) patients were ventilated and 50 (78%) needed vasopressors. 25 (39%) patients had severe ARDS, and 10 patients needed veno-venous extracorporeal membrane oxygenation. 29 (45%) patients required RRT; median time from admission to RRT start was 2 (1-9) days. MR-proADM on admission was higher in the RRT group (2.491 vs. 1.23 nmol/l; p = 0.002) and showed the highest correlation with renalSOFA. ROC curve analysis showed that MR-proADM predicts RRT with an AUC of 0.69 (95% CI: 0.543-0.828; p = 0.019). In multivariable logistic regression MR-proADM was an independent predictor (OR: 3.813, 95% CI 1.110-13.102, p<0.05) for RRT requirement.

CONCLUSION

AKI requiring RRT is frequent in ICU patients with COVID-19. MR-proADM on admission was able to predict RRT requirement, which may be of interest for risk stratification and management.

Mid-Regional Proadrenomedullin as a New Biomarker of Kidney and Cardiovascular Diseases-Is It the Future?

The increasing prevalence of cardiovascular disease and concomitant chronic kidney disease among the aging populations is responsible for considerable growth of mortality. Additionally, frequent, prolonged hospitalizations and long-term treatment generates progressive decline in bodily functions as well as substantial public health and economic burden. Accessibility to easy, non-invasive prognostic markers able to detect patients at risk of cardiovascular events may improve effective therapy and mitigate disease progression. Moreover, an early diagnosis allows time for implementation of prophylactic and educational programs that may result in decreased morbidity, improved quality of life and reduced public health expenditure. One of the promising candidates for a novel cardiovascular biomarker is mid-regional proadrenomedullin, a derivative of adrenomedullin. Adrenomedullin is a peptide hormone known for its vasodilatory, antioxidant, antiapoptotic and antifibrotic effects. A remarkable advantage of mid-regional proadrenomedullin is its longer half-life which is a prerequisite for plasma measurements. These review aims to discuss the importance of mid-regional proadrenomedullin with reference to its usefulness as a biomarker of increased cardiovascular risk and kidney disease progression.

Advance in the understanding of vasovagal syncope in children and adolescents

BACKGROUND

Vasovagal syncope (VVS) accounts for 60-80% of cases of neurally mediated syncope. VVS results from acute orthostatic intolerance and recurrent syncopal attacks, which can seriously affect an individual's quality of life. In addition, some children even experience trauma during attacks. Therefore, it is particularly important to clarify the pathogenesis of VVS. The aim of our study is to reveal the latest research progress of VVS.

DATA SOURCES

Literature that involved the pathogenesis of VVS were selected from Cochrane Library (1990-2019), EMBASE (1991-2019) and PubMed (1968-2019) databases.

RESULTS

Hypovolemia, autonomic dysfunction, vasomotor dysfunction, baroreceptor reflex abnormalities, endothelial dysfunction, serotonin surges, and gut microbiota were involved in the underlying mechanism of VVS.

CONCLUSIONS

VVS is not always a benign prognosis. Various aspects were involved in its pathogenesis. Bezold-Jarish reflex, dysfunction of the autonomic nervous system, genetic factors and so on played important roles in VVS; however, the mechanism remains unclear.

Circulating bioactive adrenomedullin as a marker of sepsis, septic shock and critical illness

Background

Biomarkers can be of help to understand critical illness and to identify and stratify sepsis. Adrenomedullin is a vasoactive hormone, with reported prognostic and potentially therapeutic value in sepsis. The primary aim of this study was to investigate the association of circulating bioactive adrenomedullin (bio-ADM) levels at intensive care unit (ICU) admission with mortality in sepsis patients and in a general ICU population. Secondary aims included the association of bio-ADM with organ failure and the ability of bio-ADM to identify sepsis.

Methods

In this retrospective observational study, adult patients admitted to one of four ICUs during 2016 had admission bio-ADM levels analysed. Age-adjusted odds ratios (OR) with 95% CI for log-2 transformed bio-ADM, and Youden’s index derived cut-offs were calculated. The primary outcome was 30-day mortality, and secondary outcomes included the need for organ support and the ability to identify sepsis.

Results

Bio-ADM in 1867 consecutive patients were analysed; 632 patients fulfilled the sepsis-3 criteria of whom 267 had septic shock. The median bio-ADM in the entire ICU population was 40 pg/mL, 74 pg/mL in sepsis patients, 107 pg/mL in septic shock and 29 pg/mL in non-septic patients. The association of elevated bio-ADM and mortality in sepsis patients and the ICU population resulted in ORs of 1.23 (95% CI 1.07–1.41) and 1.22 (95% CI 1.12–1.32), respectively. The association with mortality remained after additional adjustment for lactate in sepsis patients. Elevated bio-ADM was associated with an increased need for dialysis with ORs of 2.28 (95% CI 2.01–2.59) and 1.97 (95% CI 1.64–2.36) for the ICU population and sepsis patients, respectively, and with increased need of vasopressors, OR 1.33 (95% CI 1.23–1.42) (95% CI 1.17–1.50) for both populations. Sepsis was identified with an OR of 1.78 (95% CI 1.64–1.94) for bio-ADM, after additional adjustment for severity of disease. A bio-ADM cut-off of 70 pg/mL differentiated between survivors and non-survivors in sepsis, but a Youden’s index derived threshold of 108 pg/mL performed better.

Conclusions

Admission bio-ADM is associated with 30-day mortality and organ failure in sepsis patients as well as in a general ICU population. Bio-ADM may be a morbidity-independent sepsis biomarker.

The Rationale of Neprilysin Inhibition in Prevention of Myocardial Ischemia-Reperfusion Injury during ST-Elevation Myocardial Infarction

During the last three decades, timely myocardial reperfusion using either thrombolytic therapy or primary percutaneous intervention (pPCI) has allowed amazing improvements in outcomes with a more than halving in 1-year ST-elevation myocardial infarction (STEMI) mortality. However, mortality and left ventricle (LV) remodeling remain substantial in these patients. As such, novel therapeutic interventions are required to reduce myocardial infarction size, preserve LV systolic function, and improve survival in reperfused-STEMI patients. Myocardial ischemia-reperfusion injury (MIRI) prevention represents the main goal to reach in order to reduce STEMI mortality. There is currently no effective therapy for MIRI prevention in STEMI patients. A significant reason for the weak and inconsistent results obtained in this field may be the presence of multiple, partially redundant, mechanisms of cell death during ischemia-reperfusion, whose relative importance may depend on the conditions. Therefore, it is always more recognized that it is important to consider a "multi-targeted cardioprotective therapy", defined as an additive or synergistic cardioprotective agents or interventions directed to distinct targets with different timing of application (before, during, or after pPCI). Given that some neprilysin (NEP) substrates (natriuretic peptides, angiotensin II, bradykinin, apelins, substance P, and adrenomedullin) exert a cardioprotective effect against ischemia-reperfusion injury, it is conceivable that antagonism of proteolytic activity by this enzyme may be considered in a multi-targeted strategy for MIRI prevention. In this review, by starting from main pathophysiological mechanisms promoting MIRI, we discuss cardioprotective effects of NEP substrates and the potential benefit of NEP pharmacological inhibition in MIRI prevention.

The Cardiopulmonary Effects of the Calcitonin Gene-related Peptide Family

Cardiopulmonary diseases are very common among the population. They are high-cost diseases and there are still no definitive treatments. The roles of members of the calcitonin-gene related-peptide (CGRP) family in treating cardiopulmonary diseases have been studied for many years and promising results obtained. Especially in recent years, two important members of the family, adrenomedullin and adrenomedullin2/intermedin, have been considered new treatment targets in cardiopulmonary diseases. In this review, the roles of CGRP family members in cardiopulmonary diseases are investigated based on the studies performed to date.

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.

Pro-adrenomedullin in acute decompensation of liver cirrhosis: relationship with acute-on-chronic liver failure and short-term survival

Background and aim: Acute-on-chronic liver failure (ACLF) is characterized by the presence of acute decompensation (AD) of cirrhosis, organ failures, and high short-term mortality rates. In present study, we explored whether Pro-adrenomedullin (Pro-ADM), a biomarker of sepsis, is a potential marker of outcome in patients admitted for AD or ACLF and whether it might be of additional value to conventional prognostic scoring systems in these patients.Methods: 332 consecutive patients with AD of cirrhosis were prospectively enrolled. Pro-ADM was measured for all patients at baseline. Cox regression analysis was used to evaluate the impact of pro-ADM on short-term survival and developing ACLF during hospital stay.Results: Serum pro-ADM levels were significantly high in non-survivors (p < .001) and showed significant correlation with ALT (r = 0.181, p = .001), INR (r = 0.144, p = .009), TB (r = 0.368, p < .001), Creatinine (r = 0.145, p = .004), MELD score (r = 0.334, p = <.001) and CLI-C OF score (r = 0.375, p= <.001). Serum pro-ADM at admission was shown to be a predictor of 28-day mortality independently of MELD and CLIF-C OF scores. Prognostic models incorporating pro-ADM achieved high C index for predicting 28-day mortality in AD patients of cirrhosis. Moreover, baseline pro-ADM was found to be predictive of ACLF development during hospital stay.Conclusions: Serum pro-ADM levels correlate with multiorgan failure and are independently associated with short-term survival and ACLF development in patients admitted for AD or ACLF.

Helicobacter pylori-induced adrenomedullin modulates IFN-γ-producing T-cell responses and contributes to gastritis

Adrenomedullin (ADM) is a multifunctional peptide that is expressed by many surface epithelial cells, but its relevance to Helicobacter pylori (H. pylori)-induced gastritis is unknown. Here, we found that gastric ADM expression was elevated in gastric mucosa of H. pylori-infected patients and mice. In H. pylori-infected human gastric mucosa, ADM expression was positively correlated with the degree of gastritis; accordingly, blockade of ADM resulted in decreased inflammation within the gastric mucosa of H. pylori-infected mice. During H. pylori infection, ADM production was promoted via PI3K–AKT signaling pathway activation by gastric epithelial cells in a cagA-dependent manner, and resulted in increased inflammation within the gastric mucosa. This inflammation was characterized by the increased IFN-γ-producing T cells, whose differentiation was induced via the phosphorylation of AKT and STAT3 by ADM derived from gastric epithelial cells. ADM also induced macrophages to produce IL-12, which promoted the IFN-γ-producing T-cell responses, thereby contributing to the development of H. pylori-associated gastritis. Accordingly, blockade of IFN-γ or knockout of IFN-γ decreased inflammation within the gastric mucosa of H. pylori-infected mice. This study identifies a novel regulatory network involving H. pylori, gastric epithelial cells, ADM, macrophages, T cells, and IFN-γ, which collectively exert a pro-inflammatory effect within the gastric microenvironment.

Identification of Small-Molecule Positive Modulators of Calcitonin-like Receptor-Based Receptors

Class B G protein-coupled receptors are highly therapeutically relevant but challenges remain in identifying suitable small-molecule drugs. The calcitonin-like receptor (CLR) in particular is linked to conditions such as migraine, cardiovascular disease, and inflammatory bowel disease. The CLR cannot act as a cell-surface receptor alone but rather must couple to one of three receptor activity-modifying proteins (RAMPs), forming heterodimeric receptors for the peptides adrenomedullin and calcitonin gene-related peptide. These peptides have extended binding sites across their receptors. This is one reason why there are few small-molecule ligands that can modulate these receptors. Here we describe small molecules that are able to positively modulate the signaling of the CLR with all three RAMPs but are not active at the related calcitonin receptor. These compounds were selected from a β-arrestin recruitment screen, coupled with rounds of medicinal chemistry to improve their activity. Translational potential is shown as the compounds can positively modulate cAMP signaling in a vascular cell line model. Binding experiments do not support an extracellular domain binding site; however, molecular modeling reveals potential allosteric binding sites in multiple receptor regions. These are the first small-molecule positive modulators described for the CLR:RAMP complexes.

Adrenomedullin Is Necessary to Resolve Hyperoxia-Induced Experimental Bronchopulmonary Dysplasia and Pulmonary Hypertension in Mice

Bronchopulmonary dysplasia (BPD)-associated pulmonary hypertension (PH) is an infantile lung disease characterized by aberrant angiogenesis and impaired resolution of lung injury. Adrenomedullin (AM) signals through calcitonin receptor-like receptor and receptor activity-modifying protein 2 and modulates lung injury initiation. However, its role in lung injury resolution and the mechanisms by which it regulates angiogenesis remain unclear. Consequently, we hypothesized that AM resolves hyperoxia-induced BPD and PH via endothelial nitric oxide synthase (NOS3). AM-sufficient (ADM^+/+) or -deficient (ADM^+/-) mice were exposed to normoxia or hyperoxia through postnatal days (PNDs) 1 to 14, and the hyperoxia-exposed mice were allowed to recover in normoxia for an additional 56 days. Lung injury and development and PH were quantified at different time points. Human pulmonary microvascular endothelial cells were also used to examine the effects of AM signaling on the NOS3 pathway and angiogenesis. Lung blood vessels and NOS3 expression decreased and the extent of hyperoxia-induced BPD and PH increased in ADM^+/- mice compared with ADM^+/+ mice. Hyperoxia-induced apoptosis and PH resolved by PND14 and PND70, respectively, in ADM^+/+ mice but not in ADM^+/- mice. Knockdown of ADM, calcitonin receptor-like receptor, and receptor activity-modifying protein 2 in vitro decreased NOS3 expression, nitric oxide generation, and angiogenesis. Furthermore, NOS3 knockdown abrogated the angiogenic effects of AM. Collectively, these results indicate that AM resolves hyperoxic lung injury via NOS3.

Discovery of the Migraine Prevention Therapeutic Aimovig (Erenumab), the First FDA-Approved Antibody against a G-Protein-Coupled Receptor

In 2018, the United States Food and Drug Administration (FDA) approved Aimovig (erenumab) for the prevention of migraine. Erenumab is the first FDA approved antibody therapeutic against a G-protein-coupled receptor, the canonical receptor of calcitonin gene related peptide (CGRP-R). A novel, epitope-focused antigen was created to reconstruct the extracellular domains of the CGRP-R in a stable conformation. Successful inoculation of XenoMouse animals and careful screening yielded multiple candidate molecules for high potency and exquisite selectivity toward the CGRP-R over related receptors. These efforts led to the discovery of erenumab which has demonstrated the desired efficacy and safety profiles in multiple clinical studies for the prevention of migraine. The innovation developed in the discovery of erenumab furthers the ability to target G-coupled protein receptors using antibody approaches.

Impact of adrenomedullin blockage on lipid metabolism in female mice exposed to high-fat diet

PURPOSE

Adrenomedullin (ADM) levels are elevated in gestational and type 2 diabetic patients. ADM also stimulates lipolysis in vitro. Disturbed lipid metabolism has been implicated in the pathogenesis of diabetes. Here, we explore whether blockade of ADM is beneficial for metabolic homeostasis in a diabetic mouse model.

METHODS

C57BL/6J female mice were placed on either a control or a high fat high sucrose (HFHS) diet for 8 weeks. At week 4, osmotic mini-pumps were implanted for constant infusion of either saline or ADM antagonist, ADM_22-52. Glucose tolerance tests were performed prior to infusion and 4 weeks after infusion began. Animals were then sacrificed and visceral adipose tissue collected for further analysis.

RESULTS

Mice fed HFHS displayed glucose intolerance, increased mRNA expressions in VAT for Adm and its receptor components, Crlr. HFHS fed mice also had increased basal and isoprenaline-induced glycerol release by VAT explants. ADM_22-52 did not significantly affect glucose intolerance. ADM_22-52 did suppress basal and isoprenaline-induced glycerol release by VAT explants. This alteration was associated with enhanced mRNA expression of insulin signaling factors Insr and Glut4, and adipogenic factor Pck1.

CONCLUSIONS

HFHS diet induces glucose intolerance and enhances ADM and its receptor expressions in VAT in female mice. ADM_22-52 treatment did not affect glucose intolerance in HFHS mice, but reduced both basal and isoprenaline-induced lipolysis, which is associated with enhanced expression of genes involved in adipogenesis. These results warrant further research on the effects of ADM blockade in improving lipid homeostasis in diabetic patients.

Bioactive adrenomedullin, proenkephalin A and clinical outcomes in an acute heart failure setting

Objectives

In an acute heart failure (AHF) setting, proenkephalin A 119–159 (penKid) has emerged as a promising prognostic marker for predicting worsening renal function (WRF), while bioactive adrenomedullin (bio-ADM) has been proposed as a potential marker for congestion. We examined the diagnostic value of bio-ADM in congestion and penKid in WRF and investigated the prognostic value of bio-ADM and penKid regarding mortality, rehospitalisation and length of hospital stay in two separate European AHF cohorts.

Methods

Bio-ADM and penKid were measured in 530 subjects hospitalised for AHF in two cohorts: Swedish HeArt and bRain failure inVESTigation trial (HARVEST-Malmö) (n=322, 30.1% female; mean age 75.1+11.1 years; 12 months follow-up) and Italian GREAT Network Rome study (n=208, 54.8% female; mean age 78.5+9.9 years; no follow-up available).

Results

PenKid was associated with WRF (area under the curve (AUC) 0.65, p<0.001). In multivariable logistic regression analysis of the pooled cohort, penKid showed an independent association with WRF (adjusted OR (aOR) 1.74, p=0.004). Bio-ADM was associated with peripheral oedema (AUC 0.71, p<0.001), which proved to be independent after adjustment (aOR 2.30, p<0.001). PenKid was predictive of in-hospital mortality (OR 2.24, p<0.001). In HARVEST-Malmö, both penKid and bio-ADM were predictive of 1-year mortality (aOR 1.34, p=0.038 and aOR 1.39, p=0.030). Furthermore, bio-ADM was associated with rehospitalisation (aOR 1.25, p=0.007) and length of hospital stay (β=0.702, p=0.005).

Conclusion

In two different European AHF cohorts, bio-ADM and penKid perform as suitable biomarkers for early detection of congestion severity and WRF occurrence, respectively, and are associated with pertinent clinical outcomes.

Fremanezumab for the preventive treatment of migraine in adults

Introduction: The Calcitonin Gene-Related Peptide (CGRP) has been implicated in migraine pathophysiology due to its role in neurogenic inflammation and transmission of trigeminovascular nociceptive signal. New molecules targeting CGRP and its receptor have been developed as migraine-specific preventative treatments. Fremanezumab (or TEV-48,125, LBR-101), a human monoclonal antibody against CGRP, has been recently approved for clinical use by FDA and EMA. Areas covered: This paper briefly discusses the calcitonin family of neurotransmitters and resultant activation pathways and in-depth the chemical properties, pharmacodynamics, pharmacokinetics, clinical efficacy and safety of Fremanezumab for the prophylactic treatment of migraine. Expert opinion: Fremanezumab, a migraine-specific drug, is effective and safe as a prophylactic treatment of chronic and episodic migraine. As a monoclonal antibody, it was not associated to liver toxicity and is not expected to interact with other drugs. The long half-life might improve patients' compliance. Long-term effects of CGRP block in cardiovascular, grastrointestinal and bone functions should be evaluated in ongoing trials, since CGRP is involved in multiple biological activities in the human body. Nevertheless, targeting CGRP itself allows the receptor binding with other ligands involved in several physiological functions. Thus, the long-term treatment with Fremanezumab is expected to be associated with a lower risk of severe adverse effects.

Shear stress-induced endothelial adrenomedullin signaling regulates vascular tone and blood pressure

Hypertension is a primary risk factor for cardiovascular diseases including myocardial infarction and stroke. Major determinants of blood pressure are vasodilatory factors such as nitric oxide (NO) released from the endothelium under the influence of fluid shear stress exerted by the flowing blood. Several endothelial signaling processes mediating fluid shear stress-induced formation and release of vasodilatory factors have been described. It is, however, still poorly understood how fluid shear stress induces these endothelial responses. Here we show that the endothelial mechanosensitive cation channel PIEZO1 mediated fluid shear stress-induced release of adrenomedullin, which in turn activated its Gs-coupled receptor. The subsequent increase in cAMP levels promoted the phosphorylation of endothelial NO synthase (eNOS) at serine 633 through protein kinase A (PKA), leading to the activation of the enzyme. This Gs/PKA-mediated pathway synergized with the AKT-mediated pathways leading to eNOS phosphorylation at serine 1177. Mice with endothelium-specific deficiency of adrenomedullin, the adrenomedullin receptor, or Gαs showed reduced flow-induced eNOS activation and vasodilation and developed hypertension. Our data identify fluid shear stress-induced PIEZO1 activation as a central regulator of endothelial adrenomedullin release and establish the adrenomedullin receptor and subsequent Gs-mediated formation of cAMP as a critical endothelial mechanosignaling pathway regulating basal endothelial NO formation, vascular tone, and blood pressure.

Development of chimeric and bifunctional antagonists for CLR/RAMP receptors

CGRP, adrenomedullin (ADM), and adrenomedullin 2 (ADM2) family peptides are important neuropeptides and hormones for the regulation of neurotransmission, vasotone, cardiovascular morphogenesis, vascular integrity, and feto‒placental development. These peptides signal through CLR/RAMP1, 2 and 3 receptor complexes. CLR/RAMP1, or CGRP receptor, antagonists have been developed for the treatment of migraine headache and osteoarthritis pain; whereas CLR/RAMP2, or ADM receptor, antagonists are being developed for the treatment of tumor growth/metastasis. Based on the finding that an acylated chimeric ADM/ADM2 analog potently stimulates CLR/RAMP1 and 2 signaling, we hypothesized that the binding domain of this analog could have potent inhibitory activity on CLR/RAMP receptors. Consistent with this hypothesis, we showed that acylated truncated ADM/ADM2 analogs of 27–31 residues exhibit potent antagonistic activity toward CLR/RAMP1 and 2. On the other hand, nonacylated analogs have minimal activity. Further truncation at the junctional region of these chimeric analogs led to the generation of CLR/RAMP1-selective antagonists. A 17-amino-acid analog (Antagonist 2–4) showed 100-fold selectivity for CLR/RAMP1 and was >100-fold more potent than the classic CGRP receptor antagonist CGRP8-37. In addition, we showed (1) a lysine residue in the Antagonist 2–4 is important for enhancing the antagonistic activity, (2) an analog consisted of an ADM sequence motif and a 12-amino-acid binding domain of CGRP exhibits potent CLR/RAMP1-inhibitory activity, and (3) a chimeric analog consisted of a somatostatin analog and an ADM antagonist exhibits dual activities on somatostatin and CLR/RAMP receptors. Because the blockage of CLR/RAMP signaling prevents migraine pain and suppresses tumor growth/metastasis, further studies of these analogs, which presumably have better access to the tumor microenvironment and nerve endings at the trigeminal ganglion and synovial joints as compared to antibody-based therapies, may lead to the development of better anti-CGRP therapy and alternative antiangiogenesis therapy. Likewise, the use of bifunctional somatostatin-ADM antagonist analogs could be a promising strategy for the treatment of high-grade neuroendocrine tumors by targeting an antiangiogenesis agent to the neuroendocrine tumor microenvironment.

Adrecizumab, a non-neutralizing anti-adrenomedullin antibody, improves haemodynamics and attenuates myocardial oxidative stress in septic rats

Background

Sepsis still represents a major health issue, with persistent high morbidity and mortality rates. Cardiovascular dysfunction occurs frequently during sepsis. Adrenomedullin has been identified as a key mediator in vascular tone regulation. A non-neutralizing anti-adrenomedullin antibody, Adrecizumab, may improve haemodynamic dysfunction during caecal ligation and puncture-induced septic shock in a murine model. Our objective was to determine the role of Adrecizumab on haemodynamics in a rat model of sepsis.

Methods

For the induction of sepsis, caecal ligation and puncture were performed in Wistar male rats. Single blinded administration of Adrecizumab (2 mg/kg) or placebo was injected i.v. 24 h after the surgery, and norepinephrine was infused as the standard of care. There were > 7 animals per group. Invasive blood pressure and cardiac function (by echocardiography) were assessed until 3 h after Adrecizumab injection.

Results

A single therapeutic injection of Adrecizumab in septic rats induced rapid haemodynamic benefits with an increase in systolic blood pressure in septic-Adrecizumab rats versus untreated-septic rats (p = 0.049). The shortening fraction did not differ between the untreated-septic and septic-Adrecizumab groups. However, cardiac output increased during the 3 h after a single dose of Adrecizumab compared to untreated septic rats (p = 0.006). A single dose of Adrecizumab resulted in similar haemodynamics to the continuous administration of norepinephrine.

Three hours after a single injection of Adrecizumab, there was no change in the inflammatory phenotype (TNFα, IL-10) in the hearts of the septic rats. By contrast, 3 h after a single Adrecizumab injection, free-radical production decreased in the hearts of septic-Adrecizumab vs untreated septic rats (p < 0.05).

Conclusions

In a rat model of sepsis, a single therapeutic injection of Adrecizumab rapidly restored haemodynamic parameters and blunted myocardial oxidative stress. Currently, a proof-of-concept and dose-finding phase II trial (Adrenoss-2) is ongoing in patients with septic shock and elevated concentrations of circulating bio-adrenomedullin.

Electronic supplementary material

The online version of this article (10.1186/s40635-019-0255-0) contains supplementary material, which is available to authorized users.

Effect of scaling and root planing on gingival crevicular fluid levels of adrenomedullin in chronic periodontitis patients with and without diabetes mellitus type 2: A clinico-biochemical study

Background

Increased plasma adrenomedullin levels are usually observed in certain conditions such as diabetes mellitus (DM).

Aims and Objectives

To gauge adrenomedullin values in the gingival crevicular fluid (GCF) of healthy individuals, chronic periodontitis (CP) patients with and without DM, and diabetics without any periodontal involvement, prior and after periodontal therapy.

Materials and Methods

A total of 120 subjects were segregated into four categories of 30 each: Group 1 (healthy subjects), Group 2 (CP without DM), Group 3 (patients with CP and DM), and Group 4 (diabetics without any periodontal involvement). GCF was collected from all the patients. Nonsurgical periodontal therapy was done in Group 2 and Group 3 patients, followed up for 6 weeks, and GCF was obtained again from the same site. Enzyme-linked immunosorbent assay was used to evaluate the samples.

Results

Adrenomedullin level in the GCF was high in diabetics without any periodontal involvement than in healthy individuals and significantly elevated in those with CP and DM. Reduced adrenomedullin was noted 6 weeks postperiodontal therapy.

Conclusion

Adrenomedullin levels being higher in diabetics without any periodontal involvement than healthy controls suggest a link between DM and adrenomedullin. Furthermore, infection plays a noteworthy role in the elevation of adrenomedullin, indicating its role in periodontal disease progression.

Associations of the adrenomedullin gene polymorphism with prehypertension and hypertension in Lithuanian children and adolescents: a cross-sectional study

The aim of this study was to evaluate the association of ADM genetic variant and HBP among Lithuanian adolescents aged 12-15 years. This is a cross-sectional study of a randomly selected sample of 675 12-15-years-old schoolchildren who were surveyed during November 2010 to April 2012 in the baseline survey. Single-nucleotide polymorphism (SNP) of ADM gene (rs7129220) was evaluated using real-time PCR. Logistic regression analyses were used to test the associations of ADM (rs7129220) polymorphism with HBP under four inheritance models based on the Akaike Information Criterion (AIC) and to calculate the odds ratios. In the multivariate analysis, boys carrying ADM AG genotype (vs. carriers of ADM GG genotype), ADM AG + AA genotype (vs. carriers of ADM GG genotype) and ADM AG genotype (vs. carriers of ADM GG + AA genotype) had higher odds of having hypertension in codominant, dominant, and overdominant inheritance models. Girls with ADM AG + AA had increased odds of prehypertension compared to girls with the ADM GG genotype carriers in dominant inheritance model. Significant associations were observed in additive models separately for boys (hypertension) and girls (prehypertension). Our results indicate that ADM gene polymorphism was significantly associated with higher odds of HBP in Lithuanian adolescents aged 12-15 years.

Adrenomedullin as a Protein with Multifunctional Behavior and Effects in Various Organs and Tissues

In literature, it has been reported that adrenomedullin, which is generally thought to have vasodilator, natriuretic and diuretic effects, is synthesized in almost all body, especially CNS, vascular muscles and endothelium, heart, liver, lung, kidney, gastric mocosa, intestinal endothelium and various blood cells. It has been found that the possible effects of adrenomedullin can be demonstrated directly or indirectly by means of active mediators, neuropeptides, enzymes and hormones. It is also suggested that it regulates the endocrine system by affecting the hypothalamic-pituitary axis. It increases in heart failure, acute coronary syndromes, hypertensive conditions, cerebrovascular accessory, chronic renal failure and periodontitis and decreases in peptic ulcer and intestinal diseases. However, it is still not clear whether increase/decrease in adrenomedullin level is a cause of a disease or is a result of damage due to an illness. This peptide, which could be thought to multifunctional, should be considered as a molecule with genetic coding that may have different effects on different tissues and conditions. For all these reasons, we aimed to review the multifonctional behavior of adrenomedullin in the light of the current literature to pioneer new hypotheses and discuss possible mechanisms.

Early and late endothelial response in breast cancer metastasis in mice: simultaneous quantification of endothelial biomarkers using a mass spectrometry-based method

The endothelium plays an important role in cancer metastasis, but the mechanisms involved are still not clear. In the present work, we characterised the changes in endothelial function at early and late stages of breast cancer progression in an orthotopic model of murine mammary carcinoma (4T1 cells). Endothelial function was analysed based on simultaneous microflow liquid chromatography–tandem mass spectrometry using multiple reaction monitoring (microLC/MS-MRM) quantification of 12 endothelium-related biomarkers, including those reflecting glycocalyx disruption – syndecan-1 (SDC-1), endocan (ESM-1); endothelial inflammation – vascular cell adhesion molecule 1 (VCAM-1), intercellular adhesion molecule 1 (ICAM-1), E-selectin (E-sel); endothelial permeability – fms-like tyrosine kinase 1 (FLT-1), angiopoietin 2 (Angpt-2); and haemostasis – von Willebrand factor (vWF), tissue plasminogen activator (t-PA), plasminogen activator inhibitor 1 (PAI-1), as well as those that are pathophysiologically linked to endothelial function – adrenomedullin (ADM) and adiponectin (ADN). The early phase of metastasis in mouse plasma was associated with glycocalyx disruption (increased SDC-1 and ESM-1), endothelial inflammation [increased soluble VCAM-1 (sVCAM-1)] and increased vascular permeability (Angpt-2). During the late phase of metastasis, additional alterations in haemostasis (increased PAI-1 and vWF), as well as a rise in ADM and substantial fall in ADN concentration, were observed. In conclusion, in a murine model of breast cancer metastasis, we identified glycocalyx disruption, endothelial inflammation and increased endothelial permeability as important events in early metastasis, while the late phase of metastasis was additionally characterised by alterations in haemostasis.

Summary: A microLC/MS-MRM-based approach for simultaneous determination of endothelium-related biomarkers identified glycocalyx disruption, endothelial inflammation and increased endothelial permeability as important events in early pulmonary metastasis in a murine model of breast cancer metastasis.

Circulating Adrenomedullin Is Elevated in Gestational Diabetes and Its Role in Impaired Insulin Production by β-Cells

CONTEXT

Defective pancreatic β-cell adaptation in pregnancy plays an important role in the pathophysiology of gestational diabetes mellitus (GDM), but the molecular basis remains unclear. Objectives of this study were to determine if circulating levels of adrenomedullin (ADM) in women with GDM are elevated and to assess the effects of ADM on insulin synthesis and secretion by human pancreatic β-cells.

DESIGN

A stable gene product of ADM precursor, midregional pro-adrenomedullin (MR-proADM), was measured in plasma of pregnant women with normal glucose tolerance (NGT, n = 10) or GDM (n = 11). The β-Lox5 cell line, derived from human pancreatic β-cells, was transduced with homeodomain transcription factor pancreatic-duodenal homeobox (PDX) factor 1 (PDX1) encoding lentiviral vector and treated with different doses of ADM. mRNA for insulin, ADM, and its receptor components in β-Lox5 cells and insulin in media were measured.

RESULTS

Plasma MR-proADM levels were significantly higher in GDM compared with patients with NGT. Pancreatic β-Lox5 cells express mRNA for insulin, ADM, and its receptor components. PDX1 transduction and cell-cell contact synergistically promote β-Lox5 cells insulin mRNA and secretion. Furthermore, ADM dose-dependently inhibited mRNA and secretion of insulin in β-Lox5 cell aggregates. These inhibitory effects were blocked by ADM antagonist ADM22-52, cAMP-dependent protein kinase A inhibitor KT5720, and Erk inhibitor PD98059, but not by PI-3K the inhibitor wortmannin.

CONCLUSIONS

Circulating ADM concentrations were elevated in pregnant women with GDM. ADM suppresses insulin synthesis and secretion by pancreatic β-cells in vitro. Thus, increased circulating ADM may contribute to the defective adaptation of β-cells in diabetic pregnancies, and blockade of ADM actions with its antagonists may improve β-cell functions.

Caffeic acid phenethyl ester protects against oxidative stress and dampens inflammation via heme oxygenase 1

Periodontal disease is associated with chronic oxidative stress and inflammation. Caffeic acid phenethyl ester (CAPE), which is a potent inducer of heme oxygenase 1 (HO1), is a central active component of propolis, and the application of propolis improves periodontal status in diabetic patients. Here, primary murine macrophages were exposed to CAPE. Target gene expression was assessed by whole-genome microarray, RT-PCR and Western blotting. The antioxidative and anti-inflammatory activities of CAPE were examined by exposure of the cells to hydrogen peroxide, saliva and periodontal pathogens. The involvement of HO1 was investigated with the HO1 inhibitor tin protoporphyrin (SnPP) and knockout mice for Nrf2, which is a transcription factor for detoxifying enzymes. CAPE increased HO1 and other heat shock proteins in murine macrophages. A p38 MAPK inhibitor and Nrf2 knockout attenuated CAPE-induced HO1 expression in macrophages. CAPE exerted strong antioxidative activity. Additionally, CAPE reduced the inflammatory response to saliva and periodontal pathogens. Blocking HO1 decreased the antioxidative activity and attenuated the anti-inflammatory activity of CAPE. In conclusion, CAPE exerted its antioxidative effects through the Nrf2-mediated HO1 pathway and its anti-inflammatory effects through NF-κB inhibition. However, preclinical models evaluating the use of CAPE in periodontal inflammation are necessary in future studies.

Propolis, also known as ‘honeybee glue,’ may protect teeth and gums against periodontal disease. In periodontal disease, chronic inflammation and oxidative damage harm gum tissue and lead to tooth loss; propolis has been shown to improve periodontal health for patients with diabetes. Bees make propolis by mixing beeswax, honey, plant resins and their own saliva, and use it to patch honeycomb and prevent growth of microbes in the hive. Reinhard Gruber of the Department of Oral Biology at the Medical University of Vienna and of the Department of Periodontology, University of Bern and co-workers investigated the effects of one of propolis’ active ingredients, caffeic acid phenethyl ester (CAPE), on oxidative stress and inflammation. They found that CAPE reduced oxidative damage and dampened inflammation; further investigation revealed the genetic basis of the beneficial effects, paving the way for future clinical studies. These results may help identify alternative treatments for periodontal disease.