Anti-inflammatory effects of adrenomedullin on acute lung injury induced by Carrageenan in mice

Development of fermented rice cake containing strawberry showing anti-inflammatory effect on LPS-stimulated macrophages and paw edema induced mice

Strawberry (Fragaria ananassa) is one of the richest sources containing a wide variety of nutritive compounds. Anti-inflammatory activities of fermented rice cake made of strawberry powder as well as rice powder were evaluated. The fermented rice cake containing strawberry powder (SRC) significantly and dose-dependently inhibited NO production in LPS-stimulated RAW264.7 cells without cytotoxicity. Also, SRC effectively suppressed inflammatory gene expression, including iNOS, COX-2, IL-1β, IL-6, and TNF-α. In addition, the production of PGE2, IL-1β, IL-6, and TNF-α was significantly reduced. Furthermore, the anti-inflammatory effect of SRC was investigated using carrageenan-induced paw edema of ICR mice. It was demonstrated that pre-orally administration of SRC at a dose of 50 and 100 mg/kg BW significantly inhibited paw edema induced by carrageenan. This study suggested that the anti-inflammation activities of strawberry rice cake give the potential for increasing the commercialization of rice cake and rice products.

Fatty Acid Amide Hydrolase (FAAH) Inhibition Plays a Key Role in Counteracting Acute Lung Injury

Acute lung injury (ALI) is a group of lung illnesses characterized by severe inflammation, with no treatment. The fatty acid amide hydrolase (FAAH) enzyme is an integral membrane protein responsible for the hydrolysis of the main endocannabinoids, such as anandamide (AEA). In pre-clinical pain and inflammation models, increasing the endogenous levels of AEA and other bioactive fatty acid amides (FAAs) via genetic deletion or the pharmacological inhibition of FAAH produces many analgesic benefits in several different experimental models. To date, nobody has investigated the role of FAAH inhibition on an ALI mouse model. Mice were subjected to a carrageenan injection and treated orally 1 h after with the FAAH inhibitor URB878 dissolved in a vehicle consisting of 10% PEG-400, 10% Tween-80 and 80% saline at different doses: The inhibition of FAAH activity was able to counteract not only the CAR-induced histological alteration, but also the cascade of related inflammatory events. URB878 clears the way for further studies based on FAAH inhibition in acute lung pathologies.

TBK1 Inhibitor Exerts Antiproliferative Effect on Glioblastoma Multiforme Cells

Glioma are common malignant brain tumors, among which glioblastoma multiforme (GBM) has the worst prognosis. Different studies of GBM revealed that targeting nuclear factor B (NF-B) induced an attenuation tumor proliferation and prolonged cell survival. TBK1 {TANK [TRAF (TNF (tumor-necrosis-factor) receptor-associated factor)-associated NF-B activator]-binding kinase 1} is a serine/threonine protein kinase, and it is a member of the IB kinase (IKK) family involved in NF-B pathway activation. The aim of this study was to investigate the potential effect of BX795, an inhibitor of TBK1, in an in vitro and ex vivo model of GBM. GBM cell lines (U87 and U138) and primary GBM cells were treated with different concentrations of BX795 at different time points (24, 48, and 72h) to evaluate cell viability, autophagy, inflammation, and apoptosis. Our results demonstrated that BX795 10 M was able to reduce cell viability, showing antiproliferative effect in U87, U138, and primary GBM cells. Moreover, treatment with BX795 10 M increased the proapoptotic proteins Bax, p53, caspase 3, and caspase 9, whereas the antiapoptotic Bcl-2 expression was reduced. Additionally, our results showed a marked decrease in autophagy following BX795 treatment, reducing Atg 7, Atg 5/12, and AKT expression. The anti-inflammatory effect of BX795 was demonstrated by a significantly reduction in NIK, IKK, and TNF- expression, accompanied by a downregulation of angiogenesis. Furthermore, in primary GBM cell, BX795 10 M was able to reduce TBK1 pathway activation and SOX3 expression. In conclusion, these findings showed that TBK1 is involved in GBM proliferation, demonstrating that the inhibitor BX795, thanks to its abilities, could improve therapeutic strategies for GBM treatment.

Poly (ADP-Ribose) Polymerase Inhibitor, ABT888, Improved Cisplatin Effect in Human Oral Cell Carcinoma

Cisplatin is one of the chemotherapeutic drugs used for the management of oral carcinoma, in which combined therapies are estimated to exert superior therapeutic efficacy compared with monotherapy. It is known that poly(ADP-ribosyl)ation is implicated in a multiplicity of cellular activities, such as DNA repair and cell death. Based on these, PARP inhibitors are used for the treatment of cancers; however, the capacity of PARP inhibitors associated to anti-cancer drugs have not been completely assessed in oral carcinoma. Here, we evaluated the effects of PARPi veliparib (ABT888) in combination with cisplatin on the survival of three human oral cancer cell lines HSC-2, Ca9-22 and CAL27 and we observed the effects of ABT888 alone or in combination with cisplatin on apoptosis and DNA damage repair mechanism. The results obtained showed that ABT888 induces a cytotoxicity effect on cell viability increasing the apoptotic pathway as well as DNA strand break; moreover, our results displayed the effects with cisplatin in a dose-dependent manner. Therefore, our results indicate PARP inhibitors as adjuvants for therapeutic strategy of oral cancer.

Promotion of vascular integrity in sepsis through modulation of bioactive adrenomedullin and dipeptidyl peptidase 3

Sepsis represents one of the major medical challenges of the 21st century. Despite substantial improvements in the knowledge on pathophysiological mechanisms, this has so far not translated into novel adjuvant treatment strategies for sepsis. In sepsis, both vascular tone and vascular integrity are compromised, and contribute to the development of shock, which is strongly related to the development of organ dysfunction and mortality. In this review, we focus on dipeptidyl peptidase 3 (DPP3) and adrenomedullin (ADM), two molecules that act on the vasculature and are involved in the pathophysiology of sepsis and septic shock. DPP3 is an ubiquitous cytosolic enzyme involved in the degradation of several important signalling molecules essential for regulation of vascular tone, including angiotensin II. ADM is a key hormone involved in the regulation of vascular tone and endothelial barrier function. Previous studies have shown that circulating concentrations of both DPP3 and ADM are independently associated with the development of organ failure and adverse outcome in sepsis. We now discuss new evidence illustrating that these molecules indeed represent two distinct pathways involved in the development of septic shock. Recently, both ADM-enhancing therapies aimed at improving endothelial barrier function and vascular tone and DPP3-blocking therapies aimed at restoring systemic angiotensin responses have been shown to improve outcome in various preclinical sepsis models. Given the current lack of effective adjuvant therapies in sepsis, additional research on the therapeutic application of these peptides in humans is highly warranted.

Mid-regional pro-adrenomedullin as a supplementary tool to clinical parameters in cases of suspicion of infection in the emergency department

INTRODUCTION

Mid-regional proadrenomedullin (MR-proADM), a novel biomarker, has recently gained interest particularly with regards to its potential in assisting clinicians' decision making in patients with suspicion of infection in the emergency department (ED). A group of international experts, with research and experience in MR-proADM applications, produced this review based on their own experience and the currently available literature.

AREAS COVERED

The review provides evidence related to MR-proADM as a triaging tool in avoiding unnecessary admissions to hospital and/or inadequate discharge, and identifying patients most at risk of deterioration. It also covers the use of MR-proADM in the context of COVID-19. Moreover, the authors provide a proposal on how to incorporate MR-proADM into patients' clinical pathways in an ED setting.

EXPERT OPINION

The data we have so far on the application of MR-proADM in the ED is promising. Incorporating it into clinical scoring systems may aid the clinician's decision making and recognizing the 'ill looking well' and the 'well looking ill' sooner. However there are still many gaps in our knowledge especially during the ongoing COVID-19 waves. There is also a need for cost-effectiveness analysis studies especially in the era of increasing cost pressures on health systems globally.

Potential effect of adrenomedullin on metabolic and endocrinal dysfunctions in the experimentally induced polycystic ovary: Targeting implication of endoplasmic reticulum stress

This study investigated the potential effect of adrenomedullin (ADM) on metabolic and endocrinal dysfunctions in experimentally induced polycystic ovary. Twenty-four female Wistar rats were allocated into three groups: control; polycystic ovary syndrome (PCOS) in which PCOS was induced by letrozole, orally in a dose of 1 mg/kg once daily for 3 weeks; and ADM group in which ADM was injected intraperitonally in a dose of 3.5/μg/twice daily for 4 weeks. At the end of the experimental period, the serum sex hormone profile, ADM, fasting glucose, insulin, homeostatic model assessment of insulin resistance, and lipid parameters were determined. Ovarian tissue homogenates were used to determine malondialdehyde, total antioxidant capacity, glutathione peroxidase activity, tumor necrosis factor α, interleukin 6, B cell lymphoma-2 (Bcl-2), and Bcl-2 associated X protein. The profibrotic growth factors, including transforming growth factor β1 and connective tissue growth factor, were determined; and also, the relative gene expression of endoplasmic reticulum (ER) stress, including (Xbox-binding protein-1 [XBP-1], activating transcription factor 6 [ATF6], and homologous protein [CHOP]), serine/threonine kinase 1 (Akt1), phosphatidylinositol 3-kinase (PI3K), and peroxisome proliferator-activated receptor γ (PPAR-γ) were determined. Finally, histopathological analysis of the ovaries was evaluated. PCOS group exhibited increased ER stress, suppressing of PI3K/Akt1 and PPAR-γ pathways, imbalance of sex hormonal profile, hyperglycemia, insulin resistance, dyslipidemia, increased profibrotic factors, and abnormal ovarian histopathological picture, while ADM treatment alleviated these disturbances occurring in the PCOS model. We concluded that ADM mitigated PCOS via attenuating the ER stress, in addition to activation of PI3K/Akt1 and PPAR-γ pathways, its antioxidant, anti-inflammatory, antiapoptotic, and antifibrotic properties.

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

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

The Anti-Inflammatory and Antioxidant Effects of Sodium Propionate

The major end-products of dietary fiber fermentation by gut microbiota are the short-chain fatty acids (SCFAs) acetate, propionate, and butyrate, which have been shown to modulate host metabolism via effects on metabolic pathways at different tissue sites. Several studies showed the inhibitory effects of sodium propionate (SP) on nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) pathway. We carried out an in vitro model of inflammation on the J774-A1 cell line, by stimulation with lipopolysaccharide (LPS) and H₂O₂, followed by the pre-treatment with SP at 0.1, 1 mM and 10 mM. To evaluate the effect on acute inflammation and superoxide anion-induced pain, we performed a model of carrageenan (CAR)-induced rat paw inflammation and intraplantar injection of KO₂ where rats received SP orally (10, 30, and 100 mg/kg). SP decreased in concentration-dependent-manner the expression of cicloxigenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) following LPS stimulation. SP was able to enhance anti-oxidant enzyme production such as manganese superoxide dismutase (MnSOD) and heme oxygenase-1 (HO-1) following H₂O₂ stimulation. In in vivo models, SP (30 and 100 mg/kg) reduced paw inflammation and tissue damage after CAR and KO₂ injection. Our results demonstrated the anti-inflammatory and anti-oxidant properties of SP; therefore, we propose that SP may be an effective strategy for the treatment of inflammatory diseases.

Induction of Tolerogenic Dendritic Cells by Endogenous Biomolecules: An Update

The importance of microenvironment on dendritic cell (DC) function and development has been strongly established during the last two decades. Although DCs with general tolerogenic characteristics have been isolated and defined as a particular sub-population, it is predominantly their unequivocal biological plasticity, which allows for unparalleled responsiveness to environmental ques and shaping of their tolerogenic characteristics when interacting with tolerance-inducing biomolecules. Dendritic cells carry receptors for a great number of endogenous factors, which, after ligation, can importantly influence the development of their activation state. For this there is ample evidence merely by observation of DC characteristics isolated from various anatomical niches, e.g., the greater immunosuppressive potential of DCs isolated from intestine compared to conventional blood DCs. Endogenous biomolecules present in these environments most likely play a major role as a determinant of their phenotype and function. In this review, we will concisely summarize in what way various, tolerance-inducing endogenous factors influence DC biology, the development of their particular tolerogenic state and their subsequent actions in context of immune response inhibition and induction of regulatory T cells.

Adrenomedullin and Adrenomedullin-Targeted Therapy As Treatment Strategies Relevant for Sepsis

Sepsis remains a major medical challenge, for which, apart from improvements in supportive care, treatment has not relevantly changed over the last few decades. Vasodilation and vascular leakage play a pivotal role in the development of septic shock, with vascular leakage being caused by disrupted endothelial integrity. Adrenomedullin (ADM), a free circulating peptide involved in regulation of endothelial barrier function and vascular tone, is implicated in the pathophysiology of sepsis. ADM levels are increased during sepsis, and correlate with extent of vasodilation, as well as with disease severity and mortality. In vitro and preclinical in vivo data show that administration of ADM exerts anti-inflammatory, antimicrobial, and protective effects on endothelial barrier function during sepsis, but other work suggests that it may also decrease blood pressure, which could be detrimental for patients with septic shock. Work has been carried out to negate ADMs putative negative effects, while preserving or even potentiating its beneficial actions. Preclinical studies have demonstrated that the use of antibodies that bind to the N-terminus of ADM results in an overall increase of circulating ADM levels and improves sepsis outcome. Similar beneficial effects were obtained using coadministration of ADM and ADM-binding protein-1. It is hypothesized that the mechanism behind the beneficial effects of ADM binding involves prolongation of its half-life and a shift of ADM from the interstitium to the circulation. This in turn results in increased ADM activity in the blood compartment, where it exerts beneficial endothelial barrier-stabilizing effects, whereas its detrimental vasodilatory effects in the interstitium are reduced. Up till now, in vivo data on ADM-targeted treatments in humans are lacking; however, the first study in septic patients with an N-terminus antibody (Adrecizumab) is currently being conducted.

Topical Application of Glycolipids from Isochrysis galbana Prevents Epidermal Hyperplasia in Mice

Chronic inflammatory skin diseases such as psoriasis have a significant impact on society. Currently, the major topical treatments have many side effects, making their continued use in patients difficult. Microalgae have emerged as a source of bio-active molecules such as glycolipids with potent anti-inflammatory properties. We aimed to investigate the effects of a glycolipid (MGMG-A) and a glycolipid fraction (MGDG) obtained from the microalga Isochrysis galbana on a TPA-induced epidermal hyperplasia murine model. In a first set of experiments, we examined the preventive effects of MGMG-A and MGDG dissolved in acetone on TPA-induced hyperplasia model in mice. In a second step, we performed an in vivo permeability study by using rhodamine-containing cream, ointment, or gel to determinate the formulation that preserves the skin architecture and reaches deeper. The selected formulation was assayed to ensure the stability and enhanced permeation properties of the samples in an ex vivo experiment. Finally, MGDG-containing cream was assessed in the hyperplasia murine model. The results showed that pre-treatment with acetone-dissolved glycolipids reduced skin edema, epidermal thickness, and pro-inflammatory cytokine production (TNF-α, IL-1β, IL-6, IL-17) in epidermal tissue. The in vivo and ex vivo permeation studies showed that the cream formulation had the best permeability profile. In the same way, MGDG-cream formulation showed better permeation than acetone-dissolved preparation. MGDG-cream application attenuated TPA-induced skin edema, improved histopathological features, and showed a reduction of the inflammatory cell infiltrate. In addition, this formulation inhibited epidermal expression of COX-2 in a similar way to dexamethasone. Our results suggest that an MGDG-containing cream could be an emerging therapeutic strategy for the treatment of inflammatory skin pathologies such as psoriasis.

Adrenomedullin protects Leydig cells against lipopolysaccharide-induced oxidative stress and inflammatory reaction via MAPK/NF-κB signalling pathways

This study aimed to explore the possible benefits of adrenomedullin (ADM) in preventing oxidative stress and inflammation by using an in vitro primary culture model of rat Leydig cells exposed to lipopolysaccharide (LPS). Cell proliferation was detected through CCK-8 and BrdU incorporation assays. ROS were determined with a DCFDA kit, and cytokine concentrations were measured with ELISA assay kits. Protein production was examined by immunohistochemical staining and Western blot, and gene expression was observed through RT-qPCR. Results revealed that ADM significantly reduced LPS-induced cytotoxicity, and pretreatment with ADM significantly suppressed ROS overproduction and decreased 4-HNE and 8-OHdG expression levels and concentrations. ADM pretreatment also significantly attenuated the overactivation of enzymatic antioxidants, namely, superoxide dismutase, catalase, thioredoxin reductase, glutathione peroxidase, glutathione reductase and glutathione-S-transferase. ADM supplementation reversed the significantly increased gene expression levels and concentrations of TNF-α, IL-1β, TGF-β1, MCP-1 and MIF. ADM pretreatment significantly inhibited the gene expression and protein production of TLR-2 and 4. Furthermore, ADM pretreatment markedly reduced the phosphorylation of JNK, ERK 1/2 and p38, phosphorylation and degradation of IκBα and nuclear translocation of p65. Our findings demonstrated that ADM protects Leydig cells from LPS-induced oxidative stress and inflammation, which might be associated with MAPK/NF-κB signalling pathways.

A randomized trial of the effects of the no-carrageenan diet on ulcerative colitis disease activity

BACKGROUND: Carrageenan is a very common food additive in Western diets, but predictably causes inflammation in thousands of cell-based and animal experiments.

OBJECTIVE: To assess the impact of carrageenan exposure on the interval to relapse in patients with ulcerative colitis in remission.

METHODS: A randomized, double-blind, placebo-controlled, multicenter, clinical trial was conducted to assess if patients with ulcerative colitis in remission would have a longer interval to relapse if they followed a diet with no carrageenan. All participants were instructed in the no-carrageenan diet and were randomized to either placebo capsules or carrageenan-containing capsules. The carrageenan in the capsules was less than the average daily carrageenan intake from the diet. Relapse was defined as an increase of two or more points on the Simple Clinical Colitis Activity Index (SCCAI) and intensification of treatment for ulcerative colitis. Participants were followed by telephone calls every two weeks until relapse or one year of participation. The occurrence of relapse and inflammatory biomarkers were compared between the two groups.

RESULTS: Twelve patients completed study questionnaires. Three patients who received carrageenan-containing capsules relapsed, and none of the patients who received placebo-containing capsules relapsed (p = 0.046, log-rank test). Laboratory tests showed increases in Interleukin-6 (p = 0.02, paired t-test, two-tailed) and fecal calprotectin (p = 0.06; paired t-test, two-tailed) between the beginning and the end of study participation in the carrageenan-exposed group, but not in the placebo-group.

CONCLUSION: Carrageenan intake contributed to earlier relapse in patients with ulcerative colitis in remission. Restriction of dietary carrageenan may benefit patients with ulcerative colitis.

Adrenomedullin Regulates IL-1β Gene Expression in F4/80+ Macrophages during Synovial Inflammation

Adrenomedullin (AM) plays an important role in the regulation of inflammatory processes; however, the role and expression of AM in synovial inflammation have not been determined. To investigate the expression and role of AM in inflamed synovial tissue (ST), the gene expression profiles of AM in the ST, including synovial macrophages and fibroblasts, of a murine patellar surgical dislocation model were characterized. In addition, the effects of interleukin- (IL-) 1β and AM in cultured synovial cells were also examined. CD11c⁺ macrophages were found to be elevated in ST of the surgically dislocated patella. Higher gene expression of CD11c, IL-1β, AM, receptor activity-modifying proteins 2 (RAMP2), and 3 (RAMP3) was also observed in ST obtained from the dislocated side. AM expression was also significantly increased in synovial fibroblasts and macrophages in response to IL-1β treatment. Synovial macrophages also highly expressed RAMP3 compared to fibroblasts and this expression was further stimulated by exogenously added IL-1β. Further, the treatment of the F4/80-positive cell fraction obtained from ST with AM inhibited IL-1β expression. Taken together, these findings demonstrated that AM was produced by synovial fibroblasts and macrophages in inflamed ST and that increased levels of AM may exert anti-inflammatory effects on synovial macrophages.

Calcitonin Peptide Family Members Are Differentially Regulated by LPS and Inhibit Functions of Rat Alveolar NR8383 Macrophages

Members of the calcitonin peptide family—calcitonin gene-related peptide (CGRP), adrenomedullin (AM), and adrenomedullin2/intermedin (IMD)–exert modulatory effects upon monocytes and macrophages of various extrapulmonary origins. Utilizing the rat alveolar macrophage (AMφ) cell line NR8383, we here set out to determine to which extent these three peptides and their receptors are differentially regulated in AMφ and what specific effects they have on AMφ key functions. LPS treatment differentially up-regulated expression of the peptides and receptors. Among the three peptides, IMD mRNA content was lowest both in primary rat AMφ and NR8383 cells, whereas IMD peptide dominated in basal and LPS-stimulated secretion from NR8383 cells. Fcγ receptor-mediated phagocytosis and TNF-α production were inhibited by AM, IMD, and CGRP, whereas pro-IL-1β mRNA was slightly down-regulated exclusively by CGRP. Neither of these peptides affected IL-6 or IL-10 production. None increased intracellular calcium concentration, but AM significantly inhibited store-operated calcium entry. In conclusion, the rat AMφ cell line NR8383 is both a source and a target of the calcitonin peptide family members AM, IMD, and CGRP. Despite sharing proteins of the receptor complexes, AM, IMD, and CGRP each showed a characteristic pattern of effects and regulation, suggesting that these closely related peptides are not just redundant members of one common signaling pathway but act in concert by addressing parallel signaling cascades. Since peptide and receptor expression are up-regulated by LPS, these signaling pathways might act as inhibitory feedback mechanisms in pulmonary bacterial infection.

Regulation of endothelial and epithelial barrier functions by peptide hormones of the adrenomedullin family

The correct regulation of tissue barriers is of utmost importance for health. Barrier dysfunction accompanies inflammatory disorders and, if not controlled properly, can contribute to the development of chronic diseases. Tissue barriers are formed by monolayers of epithelial cells that separate organs from their environment, and endothelial cells that cover the vasculature, thus separating the blood stream from underlying tissues. Cells within the monolayers are connected by intercellular junctions that are linked by adaptor molecules to the cytoskeleton, and the regulation of these interactions is critical for the maintenance of tissue barriers. Many endogenous and exogenous molecules are known to regulate barrier functions in both ways. Proinflammatory cytokines weaken the barrier, whereas anti-inflammatory mediators stabilize barriers. Adrenomedullin (ADM) and intermedin (IMD) are endogenous peptide hormones of the same family that are produced and secreted by many cell types during physiologic and pathologic conditions. They activate certain G-protein-coupled receptor complexes to regulate many cellular processes such as cytokine production, actin dynamics and junction stability. In this review, we summarize current knowledge about the barrier-stabilizing effects of ADM and IMD in health and disease.

Protective Effect of Adrenomedullin on Rat Leydig Cells from Lipopolysaccharide-Induced Inflammation and Apoptosis via the PI3K/Akt Signaling Pathway ADM on Rat Leydig Cells from Inflammation and Apoptosis

This study was carried out to investigate whether ADM can modulate LPS-induced inflammation and apoptosis in rat Leydig cells. Leydig cells were treated with ADM before LPS-induced cytotoxicity. We determined the concentrations of ROS, MDA, GSH, LDH, and testosterone and the MMP. The mRNA levels of IL-1, IL-6, iNOS, and COX-2 were obtained, and the concentrations of IL-1, IL-6, NO, and PGE2 were determined. Apoptosis was assessed by TUNEL and detection of DNA fragmentation. The levels of mRNA and protein were determined for Bcl-2, Bax, caspase-3, and PARP. The protein contents for total and p-Akt were measured. ADM pretreatment significantly elevated the MMP and testosterone concentration and reduced the levels of ROS, MDA, GSH, and LDH. ADM pretreatment significantly decreased the mRNA levels of IL-1, IL-6, iNOS, and COX-2 and the concentrations of IL-1, IL-6, NO, and PGE2. LPS-induced TUNEL-positive Leydig cells were significantly decreased by ADM pretreatment, a result further confirmed by decreased DNA fragmentation. ADM pretreatment decreased apoptosis by significantly promoting Bcl-2 and inhibiting Bax, caspase-3, and PARP expressions. The LPS activity that reduced p-Akt level was significantly inhibited by ADM pretreatment. ADM protected rat Leydig cells from LPS-induced inflammation and apoptosis, which might be associated with PI3K/Akt mitochondrial signaling pathway.

Intermedin1-53 Protects Against Myocardial Fibrosis by Inhibiting Endoplasmic Reticulum Stress and Inflammation Induced by Homocysteine in Apolipoprotein E-Deficient Mice

AIM

Endoplasmic reticulum stress (ERS) and inflammation participate in cardiac fibrosis. Importantly, a novel paracrine/autocrine peptide intermedin_1-53 (IMD_1-53) in the heart inhibits myocardial fibrosis in rats. However, the mechanisms are yet to be fully elucidated.

METHODS

Myocardial fibrosis in apolipoprotein E-deficient (ApoE -/-) mice and neonatal rat cardiac fibroblasts (CFs) were induced using homocysteine (Hcy).

RESULTS

IMD_1-53 inhibited myocardial fibrosis in vivo and in vitro. Picrosirius red staining showed that IMD_1-53 reduced myocardial interstitial collagen deposition in ApoE-/- mice treated with Hcy and decreased the expression of myocardial collagen I and III, which was further verified in rat CFs. IMD_1-53 attenuated myocardial hypertrophy, as shown by cardiomyocyte cross-sectional area, ratio of heart weight to body weight, and mRNA levels of atrial natriuretic peptide and brain natriuretic peptide. IMD_1-53 inhibited the upregulation of ERS hallmarkers such as glucose-regulated protein 78 (GRP78), GRP94, activating transcription factor 6 (ATF6), ATF4, inositol-requiring enzyme 1α, spliced-X-box-binding protein-1, protein kinase receptor-like ER kinase, and eukaryotic translation initiation factor 2α in mouse myocardium and rat CFs treated with Hcy. In addition, IMD_1-53 decreased the production of inflammatory factors such as tumor necrosis factor-α, monocyte chemotactic protein-1, interleukin-6 (IL-6), and IL-1β in the mouse myocardium and rat CFs treated with Hcy. Concurrently, IMD_1-53 ameliorated the expression of nuclear factor-κB, transforming growth factor-β1, and c-Jun N-terminal kinase in the mouse myocardium and rat CFs treated with Hcy.

CONCLUSIONS

IMD potentially protects against myocardial fibrosis induced by Hcy in ApoE-/- mice, possibly via attenuating myocardial ERS and inflammation.

Effects of Adrenomedullin on Doxorubicin-Induced Cardiac Damage in Mice

Doxorubicin (DOX) is one of the best known anticancer drugs, and is used in the treatment of lymphoma, lung cancer, stomach cancer, and a number of other cancers. However, DOX has some serious side effects, the worst being lethal heart failure. Occasionally, its side effects result in the cessation of the anticancer treatment, thus having a serious adverse influence on prognosis. Agents that can be administered as alternative prophylactics or to ameliorate the side effects of DOX will be useful in increasing the safety and efficacy of anticancer therapy. Adrenomedullin (AM) is a peptide hormone secreted by many organs, including the heart; it has an organ-protective effect, including antiapoptotic, anti-inflammatory, and antioxidative stress. Blood AM levels increase with heart failure; endogenic AM has been suggested in order to protect the heart. Furthermore, exogenous AM administration has shown therapeutic effects for heart failure in patients. However, it is unclear whether AM can protect the heart against drug-induced cardiac injury in vivo. The present study was performed in order to investigate the effects of AM on DOX-induced cardiac damage. Male BALB/c mice were treated with DOX and/or AM. Exogenous AM improved the survival ratio of DOX-treated mice. In addition, AM reduced serum lactate dehydrogenase (LDH) levels following DOX treatment. On pathological examination, AM was shown to inhibit DOX-induced cardiac tissue damage, mitochondrial abnormality, and cell death. These findings suggest that AM has a protective effect against DOX-induced cardiac damage.

Adrenomedullin deficiency potentiates hyperoxic injury in fetal human pulmonary microvascular endothelial cells

Bronchopulmonary dysplasia (BPD) is a chronic lung disease of premature infants that is characterized by alveolar simplification and decreased lung angiogenesis. Hyperoxia-induced oxidative stress and inflammation contributes to the development of BPD in premature infants. Adrenomedullin (AM) is an endogenous peptide with potent angiogenic, anti-oxidant, and anti-inflammatory properties. Whether AM regulates hyperoxic injury in fetal primary human lung cells is unknown. Therefore, we tested the hypothesis that AM-deficient fetal primary human pulmonary microvascular endothelial cells (HPMEC) will have increased oxidative stress, inflammation, and cytotoxicity compared to AM-sufficient HPMEC upon exposure to hyperoxia. Adrenomedullin gene (Adm) was knocked down in HPMEC by siRNA-mediated transfection and the resultant AM-sufficient and -deficient cells were evaluated for hyperoxia-induced oxidative stress, inflammation, cytotoxicity, and Akt activation. AM-deficient HPMEC had significantly increased hyperoxia-induced reactive oxygen species (ROS) generation and cytotoxicity compared to AM-sufficient HPMEC. Additionally, AM-deficient cell culture supernatants had increased macrophage inflammatory protein 1α and 1β, indicating a heightened inflammatory state. Interestingly, AM deficiency was associated with an abrogated Akt activation upon exposure to hyperoxia. These findings support the hypothesis that AM deficiency potentiates hyperoxic injury in primary human fetal HPMEC via mechanisms entailing Akt activation.

Adrenomedullin and tumour microenvironment

Adrenomedullin (AM) is a regulatory peptide whose involvement in tumour progression is becoming more relevant with recent studies. AM is produced and secreted by the tumour cells but also by numerous stromal cells including macrophages, mast cells, endothelial cells, and vascular smooth muscle cells. Most cancer patients present high levels of circulating AM and in some cases these higher levels correlate with a worst prognosis. In some cases it has been shown that the high AM levels return to normal following surgical removal of the tumour, thus indicating the tumour as the source of this excessive production of AM. Expression of this peptide is a good investment for the tumour cell since AM acts as an autocrine/paracrine growth factor, prevents apoptosis-mediated cell death, increases tumour cell motility and metastasis, induces angiogenesis, and blocks immunosurveillance by inhibiting the immune system. In addition, AM expression gets rapidly activated by hypoxia through a HIF-1α mediated mechanism, thus characterizing AM as a major survival factor for tumour cells. Accordingly, a number of studies have shown that inhibition of this peptide or its receptors results in a significant reduction in tumour progression. In conclusion, AM is a great target for drug development and new drugs interfering with this system are being developed.

Study of the association of adrenomedullin and basic-fibroblast growth factors with the peripheral arterial blood flow and endothelial dysfunction biomarkers in type 2 diabetic patients with peripheral vascular insufficiency

Background

Progressive micro-vascular vaso-degeneration is the major factor in progression of diabetic complications. Adrenomedullin (AM) and basic-Fibroblast growth factor (b-FGF) are strongly correlated with angiogenesis in vascular diseases. This study aims to provide base line data regarding the vascular effects and correlation of AM, and b-FGF with the peripheral blood flow in diabetic patients with peripheral vascular disease (PVD), and their effect on endothelial dysfunction markers. Ninety age- and sex matched females were enrolled in the study: 30 were controls, 30 had diabetes without complications (group II) and 30 had diabetes with PVD (group III) diagnosed by ankle/ brachial index (A/BI). Plasma levels of AM, b-FGF, intercellular adhesion molecule −1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) were measured by indirect enzyme immunoassay (ELISA).

Results

There was a significant increase in plasma AM, VCAM-1and ICAM-1, while a significant decrease in plasma b-FGF in diabetic patients with PVD (p < 0.05). A positive correlation was observed between plasma AM, b-FGF and A/BI and a negative correlation with VCAM −1 and ICAM in diabetic PVD. AM was not a predictor, while b-FG, VCAM-1 and ICAM-1 could be predictors for peripheral blood flow in diabetic PVD.

Conclusion

This study elucidates for the first time that AM and b-FGF are correlated and have a direct impact on the peripheral blood flow, the rise of AM in diabetic PVD may be a consecutive and compensatory vasculo-protective effect as its angiogenic and anti-inflammatory properties act to relief the endothelial insult. Down expression of b-FGF may be a predisposing factor for micro-vascular derangement. It is not clear if the rise of AM and the decline of b- FGF levels may be consequences or predisposing factors for VCAM-1 and ICAM-1 elevation as these endothelial dysfunction biomarkers could reduce peripheral blood flow and vascular integrity. It is optimistic to believe that drug intervention through AM and b-FGF administration together with reversing the endothelial inflammatory process by targeting VCAM and ICAM could reduce the prevalence of diabetic vascular complications, reduce the risk of cerebrovascular and cardiovascular morbidity in diabetes through normalizing vascular endothelium function and peripheral blood flow.

Role of a histamine 4 receptor as an anti-inflammatory target in carrageenan-induced pleurisy in mice

The histamine 4 receptor (H4R) is expressed primarily on cells involved in inflammation and immune responses. Despite much research into inflammatory diseases, no drugs with favourable safety profiles are yet available for their treatment. The aim of the present study was to determine the potential anti-inflammatory effect of 4-methylhistamine (4-MeH) or JNJ77777120 (JNJ) and to explore the role of H4R in a mouse model of carrageenan (Cg) -induced pleurisy. A single dose of 4-MeH or JNJ (30 mg/kg) was administered intraperitoneally 1 hr before Cg administration. The results illustrate that both the numbers of CD4(+) , CD25(+) , CD4(+)  CD25(+) , GITR(+) , GITR(+)  IL-17A(+) -expressing T cells and the levels of T helper type 1 (Th1)/Th17 cytokines were markedly increased in both the Cg-treated and 4-MeH-treated groups, whereas the cytokines produced by Th2 cells were significantly decreased in the same groups. However, JNJ treatment significantly decreased both the number of T-cell subsets and GITR(+) , GITR(+)  IL-17A(+) -expressing T cells, and the production of Th1/Th17 cytokines. Further, JNJ up-regulated the expression of the Th2 cytokines. RT-PCR analysis revealed an increased expression of interleukin-1β, tumour necrosis factor-α, monocyte chemoattractant protein-1 and intercellular adhesion molecule-1 in the Cg-treated and 4-MeH-treated groups, which was reduced by treatment with JNJ in lung tissues. Moreover, histological examinations revealed anti-inflammatory effects of JNJ, whereas 4-MeH worsened Cg-induced inflammation. In conclusion, the results of the present work clearly indicate that JNJ possesses important anti-inflammatory properties that are increased in 4-MeH-treated mice, suggesting that H4R are involved in pleurisy and that JNJ has an anti-inflammatory effect in associated disease conditions.

Diethylcarbamazine attenuates the development of carrageenan-induced lung injury in mice

Diethylcarbamazine (DEC) is an antifilarial drug with potent anti-inflammatory properties as a result of its interference with the metabolism of arachidonic acid. The aim of the present study was to evaluate the anti-inflammatory activity of DEC in a mouse model of acute inflammation (carrageenan-induced pleurisy). The injection of carrageenan into the pleural cavity induced the accumulation of fluid containing a large number of polymorphonuclear cells (PMNs) as well as infiltration of PMNs in lung tissues and increased production of nitrite and tumor necrosis factor-α and increased expression of interleukin-1β, cyclooxygenase (COX-2), and inducible nitric oxide synthase. Carrageenan also induced the expression of nuclear factor-κB. The oral administration of DEC (50 mg/Kg) three days prior to the carrageenan challenge led to a significant reduction in all inflammation markers. The present findings demonstrate that DEC is a potential drug for the treatment of acute lung inflammation.

Adrenomedullin binding improves catecholamine responsiveness and kidney function in resuscitated murine septic shock

Purpose

Adrenomedullin (ADM) has been referred to as a double-edged sword during septic shock: On one hand, ADM supplementation improved organ perfusion and function, attenuated systemic inflammation, and ultimately reduced tissue apoptosis and mortality. On the other hand, ADM overproduction can cause circulatory collapse and organ failure due to impaired vasoconstrictor response and reduced myocardial contractility. Since most of these data originate from un-resuscitated shock models, we tested the hypothesis whether the newly developed anti-ADM antibody HAM1101 may improve catecholamine responsiveness and thus attenuate organ dysfunction during resuscitated murine, cecal ligation and puncture (CLP)-induced septic shock.

Methods

Immediately after CLP, mice randomly received vehicle (phosphate-buffered saline, n = 11) or HAM1101 (n = 9; 2 μg·g⁻¹). Fifteen hours after CLP, animals were anesthetized, mechanically ventilated, instrumented, and resuscitated with hydroxyethylstarch and continuous i.v. norepinephrine to achieve normotensive hemodynamics (mean arterial pressure > 50 to 60 mmHg).

Results

HAM1101 pretreatment reduced the norepinephrine infusion rates required to achieve hemodynamic targets, increased urine flow, improved creatinine clearance, and lowered neutrophil gelatinase-associated lipocalin blood levels, which coincided with reduced expression of the inducible nitric oxide synthase and formation of peroxynitrite (nitrotyrosine immunostaining) in the kidney and aorta, ultimately resulting in attenuated systemic inflammation and tissue apoptosis.

Conclusions

During resuscitated murine septic shock, early ADM binding with HAM1101 improved catecholamine responsiveness, blunted the shock-related impairment of energy metabolism, reduced nitrosative stress, and attenuated systemic inflammatory response, which was ultimately associated with reduced kidney dysfunction and organ injury.

Electronic supplementary material

The online version of this article (doi:10.1186/2197-425X-1-2) contains supplementary material, which is available to authorized users.