HB-EGF stimulates eNOS expression and nitric oxide production and promotes eNOS dependent angiogenesis

A 1, 4-benzoquinone derivative isolated from Ardisia crispa (Thunb.) A. DC. root suppresses angiogenesis via its angiogenic signaling cascades

The root hexane extract of Ardisia crispa (ACRH), which belongs to the Primulaceae family, has been reported to possess anti-inflammatory, chemopreventive, anti-arthritic, and antiangiogenic activities. In this study, we isolated a p-benzoquinone derivative, 2-methoxy-6-undecyl-1,4-benzoquinone (AC2), from ACRH and investigated its potential antiangiogenic activity in human umbilical vein endothelial cells (HUVECs) and zebrafish embryo models. Prior to this study, AC2 was characterized using 1H NMR spectroscopy and MS. AC2 significantly suppressed HUVEC proliferation in a time-independent manner, with an IC50 value of 1.35 ± 0.05, 1.15 ± 0.02, and 1.00 ± 0.01 µg/mL at 24, 48, and 72 h, respectively. AC2 also induced apoptosis in HUVECs and significantly suppressed their migration, invasion, and tube formation in a concentration-dependent manner. Additionally, AC2 significantly attenuated most of the analyzed protein markers, including pro-MMP-2, VEGF-C, VEGF-D, angiopoietin-2, endothelin-1, fibroblast growth factor (FGF)-1, FGF-2, follistatin, heparin-binding epidermal growth factor-like growth factor (HB-EGF), and hepatocyte growth factor (HGF) at all tested concentrations. Furthermore, AC2 significantly inhibited zebrafish embryo intersegmental vessels (ISVs), confirming its antiangiogenic role. In conclusion, AC2 exhibits a potential anti-angiogenic effect by suppressing several proangiogenic and growth factors. Further studies are needed to investigate their effects on other excessive angiogenic diseases.

The epidermal growth factor receptor in healthy pregnancy and preeclampsia

The epidermal growth factor receptor (EGFR) is expressed robustly in the placenta, and critical processes of pregnancy such as placental growth and trophoblast fusion are dependent on EGFR function. However, the role that aberrant EGFR signaling might play in the etiology and/or maintenance of preeclampsia (PE) remains largely unexplored. Recently, we have shown that overexpression of EGFR in cultured uterine artery endothelial cells (UAEC), which express little endogenous EGFR, remaps responsiveness away from vascular endothelial growth factor receptor (VEGFR) signaling and toward EGFR, suggesting that endothelial EGFR expression may be kept low to preserve VEGFR control of angiogenesis. Here we will consider the evidence for the possibility that the endothelial dysfunction observed in PE might in some cases result from elevation of endothelial EGFR. During pregnancy, trophoblasts are known to synthesize large amounts of EGFR protein, and the placenta regularly releases syncytiotrophoblast-derived exosomes and microparticles into the maternal circulation. Although there are no reports of elevated EGFR gene expression in preeclamptic endothelial cells, the ongoing shedding of placental vesicles into the vascular system raises the possibility that EGFR-rich vesicles might fuse with endothelium, thereby contributing to the symptoms of PE by interrupting angiogenesis and blocking pregnancy-adapted vasodilatory function.

Biomaterials-Based Regenerative Strategies for Skin Tissue Wound Healing

Skin tissue wound healing proceeds through four major stages, including hematoma formation, inflammation, and neo-tissue formation, and culminates with tissue remodeling. These four steps significantly overlap with each other and are aided by various factors such as cells, cytokines (both anti- and pro-inflammatory), and growth factors that aid in the neo-tissue formation. In all these stages, advanced biomaterials provide several functional advantages, such as removing wound exudates, providing cover, transporting oxygen to the wound site, and preventing infection from microbes. In addition, advanced biomaterials serve as vehicles to carry proteins/drug molecules/growth factors and/or antimicrobial agents to the target wound site. In this review, we report recent advancements in biomaterials-based regenerative strategies that augment the skin tissue wound healing process. In conjunction with other medical sciences, designing nanoengineered biomaterials is gaining significant attention for providing numerous functionalities to trigger wound repair. In this regard, we highlight the advent of nanomaterial-based constructs for wound healing, especially those that are being evaluated in clinical settings. Herein, we also emphasize the competence and versatility of the three-dimensional (3D) bioprinting technique for advanced wound management. Finally, we discuss the challenges and clinical perspective of various biomaterial-based wound dressings, along with prospective future directions. With regenerative strategies that utilize a cocktail of cell sources, antimicrobial agents, drugs, and/or growth factors, it is expected that significant patient-specific strategies will be developed in the near future, resulting in complete wound healing with no scar tissue formation.

Injectable thioketal-containing hydrogel dressing accelerates skin wound healing with the incorporation of reactive oxygen species scavenging and growth factor release

Wound healing is a complex dynamic process. During the occurrence of skin injury, the excessive reactive oxygen species (ROS) level is associated with sustained inflammatory response, which limits efficient wound repair. Although multifunctional hydrogels are considered ideal wound dressings due to their unique advantages, the development of hydrogel dressings with rapid gelling rates, shape adaptation, and antioxidant function is still a vital challenge. In this work, a ROS-responsive injectable polyethylene glycol hydrogel containing thioketal bonds (PEG-TK hydrogel) was synthesized and utilized to deliver epidermal growth factor (EGF). We adopted bio-orthogonal click chemistry for crosslinking the polymer chains to obtain the EGF@PEG-TK hydrogel with fast gelation time, injectability and shape-adaptability. More interestingly, the thioketal bonds in the PEG-TK hydrogel not only scavenged excessive ROS in the wound sites but also achieved responsive and controlled EGF release to facilitate regeneration. The EGF@PEG-TK hydrogel treatment offered the benefits of protecting cells from oxidative stress, accelerating wound closure, and reducing scar formation in the full-thickness skin defect model. This work provides a promising strategy for developing antioxidant hydrogel dressing for facilitating the repair of wounds.

Photobiomodulation Therapy to Promote Angiogenesis in Diabetic Mice with Hindlimb Ischemia

Objective: To assess whether photobiomodulation therapy (PBMT) induces angiogenesis in diabetic mice with hindlimb ischemia (HLI). Background: Patients with diabetes mellitus (DM) are at high risk of developing peripheral arterial disease (PAD) in the lower extremities. PBMT has been shown to promote angiogenesis both in vitro and in vivo and could be a treatment for DM patients with PAD. Methods: Femoral artery ligation/excision in mice was performed to induce HLI as an animal model of PAD. PBMT at a dose of 660 nm and 1.91 J/cm² was delivered for 10 min on 5 consecutive days after the HLI surgery. Control mice received HLI only. Mice in the DM group were injected with streptozocin to induce diabetes before HLI surgery. Mice in the laser and DM+ laser groups received both HLI and PBMT, and the latter group had induced DM. After the laser treatment, lower limb blood flow was evaluated by laser Doppler. The capillary density and CD31 were analyzed by immunofluorescence staining, and protein levels of vascular endothelial growth factor (VEGF)-A, hypoxia-inducible factor-1α (HIF-1α), inducible nitric oxide synthase (iNOS), endothelial nitric oxide synthase (eNOS), and extracellular signal-regulated kinases (ERK) were measured by Western blotting of tissue samples. Results: Compared with the control and DM mice, the laser and DM+ laser groups had more than double the capillary density and blood perfusion rate. Levels of CD31 and VEGF-A proteins in groups that received laser were increased by 1.9- to 3.2-fold compared with groups that did not undergo laser treatment. Animals treated with PBMT exhibited significantly increased HIF-1α expression and ERK phosphorylation compared with animals that did not receive this treatment, and the amount of phospho-eNOS and iNOS increased and decreased, respectively. Conclusions: PBMT can induce therapeutic angiogenesis, indicating that low intensity laser could be a novel treatment for PAD patients.

A Vessel for Change: Endothelial Dysfunction in Cerebral Small Vessel Disease

The blood vessels of the brain are lined with endothelial cells and it has been long known that these help to regulate blood flow to the brain. However, there is increasing evidence that these cells also interact with the surrounding brain tissue. These interactions change when the endothelial cells become dysfunctional and have an impact in diseases such as cerebral small vessel disease, the leading cause of vascular dementia. In this review, we focus on what endothelial dysfunction is, what causes it, how it leads to surrounding brain pathology, how researchers can investigate it with current models, and where this might lead in the future for dementia therapies.

Pharmacological Effects of Fasudil on Flap Survival in a Rodent Model

BACKGROUND

Necrosis of the perforator flap is a critical problem. Fasudil, an inhibitor of Rho-associated coiled-coil containing kinase, has antiapoptosis activity and attenuates oxidative stress in many diseases. We characterized the effects of fasudil through intraperitoneal injection on perforator flap survival and identified its possible mechanism.

METHODS AND MATERIALS

Rats were divided into a control group (without surgery), a flap group (only surgery), and a fasudil group (surgery plus fasudil). Perforator flaps were made on the backs of the rats. The expression of vascular endothelial growth factor, the protein kinase B (PKB/Akt), endothelial nitric oxide synthase, Bax, Bcl-2, Beclin-1, P62, and LC3 II/LC3 I was determined by Western blot at day 3 after surgery. Nitric oxide (NO) components, superoxide dismutase, and malondialdehyde were also measured at day 3. The survival rate and laser Doppler perfusion imaging were performed at day 7 after surgery.

RESULT

The group with fasudil treatment exhibited the higher survival rates and angiogenesis levels. Fasudil also induced the activation of Akt/eNOS/NO pathway detected by the Western blot and NO expression kit. Furthermore, Western blot results showed fasudil-attenuated apoptosis through a raised Bcl-2/Bax rate and enhanced autophagy levels through raised beclin-1, decreased p62, and the elevated rate of LC3 II/LC3 I. Finally, fasudil increased superoxide dismutase and decreased malondialdehyde.

CONCLUSIONS

In conclusion, fasudil treatment decreased necrosis of perforator flaps possibly by affecting the Akt/eNOS/NO pathway, attenuating apoptosis and activating autophagy.

Photo-responsive supramolecular hyaluronic acid hydrogels for accelerated wound healing

Supramolecular hydrogels confer control over structural properties in a reversible, dynamic, and biomimetic fashion. The design of supramolecular hydrogels with an improved structural and functional recapitulation of damaged organs is important for clinical applications. For wound healing management, in particular, an effective healing process, through the modulation of epidermal growth factor (EGF) delivery using supramolecular polysaccharide hydrogels, has yet to be developed. In this study, photo-responsive supramolecular polysaccharide hydrogels were formed through host-guest interactions between azobenzene and β-cyclodextrin groups conjugated to hyaluronic acid chains. By exploiting the photoisomerization properties of azobenzene under different wavelengths, a supramolecular hydrogel featuring a dynamic spatial network crosslink density through the application of a light stimulus was obtained. Under ultra violet (UV) light, the loosened hydrogel can rapidly release EGF, thereby enhancing EGF delivery at the wound site. Based on an in vivo assessment of the healing process through a full-thickness skin defect model, the controlled EGF release from a supramolecular hydrogel exhibited superior wound healing efficiency with respect to granulation tissue formation, growth factor levels, and angiogenesis. Therefore, the proposed supramolecular hydrogels are potentially valuable as controlled delivery systems for future clinical wound healing applications.

Deficiency of DICER reduces the invasion ability of trophoblasts and impairs the pro-angiogenic effect of trophoblast-derived microvesicles

DICER is a key rate‐limiting enzyme in the canonical miRNAs biogenesis pathway, and DICER and DICER‐dependent miRNAs have been proved to play essential roles in many physiological and pathological processes. However, whether DICER is involved in placentation has not been studied. Successful spiral artery remodelling is one of the key milestones during placentation, which depends mostly on the invasion of trophoblasts and the crosstalk between trophoblasts and endothelial cells. In the present study, we show that DICER knockdown impairs the invasion ability of both primary extravillous trophoblasts (EVT) and HTR8/SVneo (HTR8) cell lines. The decreased invasion of HTR8 cells upon DICER knockdown (sh‐Dicer) was partly due to the up‐regulation of miR‐16‐2‐3p, which led to a reduced expression level of the collagen type 1 alpha 2 chain (COL1A2) protein. Moreover, microvesicles (MVs) can be secreted by HTR8 cells and promote the tube formation ability of human umbilical cord vein endothelial cells (HUVECs). However, conditioned medium and MVs derived from sh‐Dicer HTR8 cells have an anti‐angiogenic effect, due to reduced angiogenic factors and increased anti‐angiogenic miRNAs (including let‐7d, miR‐1‐6‐2 and miR‐15b), respectively. In addition, reduced protein expression of DICER is found in PE placenta by immunoblotting and immunohistochemistry. In summary, our study uncovered a novel DICER‐miR‐16‐2‐COL1A2 mediated pathway involved in the invasion ability of EVT, and DICER‐containing MVs mediate the pro‐angiogenic effect of trophoblast‐derived conditioned medium on angiogenesis, implying the involvement of DICER in the pathogenesis of PE.

Circulating levels of inflammatory parameters pentraxin-3, cyclophilin and heparin-binding epidermal growth factor-like growth factor in patients with ST-elevation myocardial infarction

Inflammatory biomarkers - pentraxin-3 (PTX3), cyclophilin A (CypA) and heparin-binding epidermal growth factor-like growth factor (HB-EGF) were examined in patients with ST-segment elevation myocardial infarction (STEMI) undergoing revascularization with primary percutaneous coronary intervention (pPCI) and stent implanting. Investigated parameters were compared between patients with and without obstructive coronary artery disease (CAD). In addition, their changes were tested in circulation before and immediately after pPCI. The study group consisted of 81 STEMI patients. Patients were classified in the STEMI-CAD group if they had significant obstructive CAD or in MINOCA group if they had no significant stenosis. In STEMI-CAD patients inflammatory parameters were determined prior to and after pPCI intervention. Immediately after pPCI, in STEMI-CAD patients levels of PTX3 were significantly lower (1.52 vs. 2.17 μg/L, p < .001), while the levels of HB-EGF (14.61 vs. 12.03 pg/L, p < .001) and CyPA (15.95 vs. 8.62 μg/L, p < .001) were significantly higher compared to levels before pPCI. STEMI-CAD patients had lower PTX3 values 2.17 μg/L (1.55-5.10 μg/L) than MINOCA patients 5.06 μg/L (2.77-6.7 μg/L), p = .046. Diagnostic accuracy of PTX3 for discrimination MINOCA from STEMI-CAD patients was low (area under receiver operating characteristic curve = 0.770). Evaluation of PTX3 values may be helpful in the understanding of MINOCA aetiology but they couldn't distinguish stenosis severity in STEMI patients. Inflammatory biomarkers significantly changed after pPCI but the possibility of clinical use of these biomarkers needs to be evaluated in a larger prospective study.

Local pharmacological induction of angiogenesis: Drugs for cells and cells as drugs

The past decades have seen significant advances in pro-angiogenic strategies based on delivery of molecules and cells for conditions such as coronary artery disease, critical limb ischemia and stroke. Currently, three major strategies are evolving. Firstly, various pharmacological agents (growth factors, interleukins, small molecules, DNA/RNA) are locally applied at the ischemic region. Secondly, preparations of living cells with considerable bandwidth of tissue origin, differentiation state and preconditioning are delivered locally, rarely systemically. Thirdly, based on the notion, that cellular effects can be attributed mostly to factors secreted in situ, the cellular secretome (conditioned media, exosomes) has come into the spotlight. We review these three strategies to achieve (neo)angiogenesis in ischemic tissue with focus on the angiogenic mechanisms they tackle, such as transcription cascades, specific signalling steps and cellular gases. We also include cancer-therapy relevant lymphangiogenesis, and shall seek to explain why there are often conflicting data between in vitro and in vivo. The lion's share of data encompassing all three approaches comes from experimental animal work and we shall highlight common technical obstacles in the delivery of therapeutic molecules, cells, and secretome. This plethora of preclinical data contrasts with a dearth of clinical studies. A lack of adequate delivery vehicles and standardised assessment of clinical outcomes might play a role here, as well as regulatory, IP, and manufacturing constraints of candidate compounds; in addition, completed clinical trials have yet to reveal a successful and efficacious strategy. As the biology of angiogenesis is understood well enough for clinical purposes, it will be a matter of time to achieve success for well-stratified patients, and most probably with a combination of compounds.

2-Methoxyestradiol causes matrix metalloproteinase 9-mediated transactivation of epidermal growth factor receptor and angiotensin type 1 receptor downregulation in rat aortic smooth muscle cells

Studies have demonstrated the therapeutic potential of estrogen metabolite 2-methoxyestradiol (2ME2) in several cardiovascular disorders, including hypertension. However, the exact mechanism(s) remains unknown. In this study, primary rat aortic smooth muscle cells (RASMCs) were exposed to 2ME2, and angiotensin type 1 receptor (AT1R) expression, function, and associated signaling pathways were evaluated. In RASMCs, 2ME2 downregulated AT1R expression in a concentration- and time-dependent manner, which was correlated with reduced mRNA expression. The 2ME2 effect was through G protein-coupled receptor 30 (GPR30) that inhibits second messenger cAMP. Moreover, 2ME2 exposure phosphorylated ERK1/2 that was sensitive to MEK inhibitor PD98059. Selective epidermal growth factor receptor (EGFR) inhibitor AG1478 blocked 2ME2-induced EGFR transactivation and attenuated subsequent phosphorylation of ERK1/2 preventing AT1R downregulation. The transactivation was dependent on 2ME2-induced release of matrix metalloproteinase 9 (MMP9) and epidermal growth factor demonstrated by ELISA. Furthermore, transfection with small interfering (si) RNA targeting MMP9 impeded ERK1/2 activation and AT1R downregulation in response to 2ME2 and G1 stimulation. Interestingly, under similar conditions, stimulation of GPR30 with the selective agonist G1 elicited similar signaling pathways and downregulated the AT1R expression that was reversed by GPR30 antagonist G15. Furthermore, 2ME2 and G1 inhibited angiotensin II (ANG II) induced Ca2+ release, a response consistent with AT1R downregulation. Collectively, our study demonstrates for the first time that 2ME2 binding to GPR30 induces MMP9 specific transactivation of EGFR that mediates ERK1/2-dependent downregulation of AT1R in RASMCs. The study provides critical insights into the newly discovered role and signaling pathways of 2ME2 in the regulation of AT1R in vascular cells and its potential to be developed as a therapeutic agent that ameliorates hypertension.

Ticagrelor Improves Endothelial Function by Decreasing Circulating Epidermal Growth Factor (EGF)

Ticagrelor is one of the most powerful P2Y₁₂ inhibitor. We have recently reported that, in patients with concomitant Stable Coronary Artery Disease (SCAD) and Chronic Obstructive Pulmonary Disease (COPD) undergoing percutaneous coronary intervention (PCI), treatment with ticagrelor, as compared to clopidogrel, is associated with an improvement of the endothelial function (Clinical Trial NCT02519608). In the present study, we showed that, in the same population, after 1 month treatment with ticagrelor, but not with clopidogrel, there is a decrease of the circulating levels of epidermal growth factor (EGF) and that these changes in circulating levels of EGF correlate with on-treatment platelet reactivity. Furthermore, in human umbilical vein endothelial cells (HUVEC) incubated with sera of the patients treated with ticagrelor, but not with clopidogrel there is an increase of p-eNOS levels. Finally, analyzing the changes in EGF and p-eNOS levels after treatment, we observed an inverse correlation between p-eNOS and EGF changes only in the ticagrelor group. Causality between EGF and eNOS activation was assessed in vitro in HUVEC where we showed that EGF decreases eNOS activity in a dose dependent manner. Taken together our data indicate that ticagrelor improves endothelial function by lowering circulating EGF that results in the activation of eNOS in the vascular endothelium.

The somite-secreted factor Maeg promotes zebrafish embryonic angiogenesis

MAM and EGF containing gene (MAEG), also called Epidermal Growth Factor-like domain multiple 6 (EGFL6), belongs to the epidermal growth factor repeat superfamily. The role of Maeg in zebrafish angiogenesis remains unclear. It was demonstrated that maeg was dynamically expressed in zebrafish developing somite during a time window encompassing many key steps in embryonic angiogenesis. Maeg loss-of-function embryos showed reduced endothelial cell number and filopodia extensions of intersegmental vessels (ISVs). Maeg gain-of-function induced ectopic sprouting evolving into a hyperbranched and functional perfused vasculature. Mechanistically we demonstrate that Maeg promotes angiogenesis dependent on RGD domain and stimulates activation of Akt and Erk signaling in vivo. Loss of Maeg or Itgb1, augmented expression of Notch receptors, and inhibiting Notch signaling or Dll4 partially rescued angiogenic phenotypes suggesting that Notch acts downstream of Itgb1. We conclude that Maeg acts as a positive regulator of angiogenic cell behavior and formation of functional vessels.

Topical mevastatin promotes wound healing by inhibiting the transcription factor c-Myc via the glucocorticoid receptor and the long non-coding RNA Gas5

Diabetic foot ulcers (DFUs), a life-threatening complication of diabetes mellitus, have limited treatment options, often resulting in amputations. HMG-CoA reductase inhibitors such as statins are cholesterol-reducing agents that may provide a new therapeutic option. Statins target the cholesterol pathway and block the synthesis of the wound-healing inhibitors farnesyl pyrophosphate (FPP) and cortisol, ligands for the glucocorticoid receptor (GR). Here we demonstrate that the naturally occurring statin mevastatin reverses FPP's effects and promotes healing by using in vitro wound healing assays, human ex vivo and porcine in vivo wound models, and DFU tissue. Moreover, we measured cortisol levels by ELISA and found that mevastatin inhibited cortisol synthesis in keratinocytes and biopsies from patients with DFU. Of note, topical mevastatin stimulated epithelialization and angiogenesis in vivo Mevastatin also reversed FPP-mediated induction of the GR target, the transcription factor c-Myc (a biomarker of non-healing wounds), in porcine and human wound models. Importantly, mevastatin reversed c-Myc overexpression in DFUs. It induced expression of the long noncoding RNA Gas5 that blocks c-Myc expression, which was confirmed by overexpression studies. We conclude that topical mevastatin accelerates wound closure by promoting epithelialization via multiple mechanisms: modulation of GR ligands and induction of the long noncoding RNA Gas5, leading to c-Myc inhibition. In light of these findings, we propose that repurposing statin drugs for topical treatment of DFUs may offer another option for managing this serious condition.

A New Role for Helicobacter pylori Urease: Contributions to Angiogenesis

Helicobacter pylori is a pathogen involved in gastric diseases such as ulcers and carcinomas. H. pylori's urease is an important virulence factor produced in large amounts by this bacterium. In previous studies, we have shown that this protein is able to activate several cell types like neutrophils, monocytes, platelets, endothelial cells, and gastric epithelial cells. Angiogenesis is a physiological process implicated in growth, invasion and metastization of tumors. Here, we have analyzed the angiogenic potential of H. pylori urease (HPU) in gastric epithelial cells. No cytotoxicity was observed in AGS, Kato-III, and MKN28 gastric cell lines treated with 300 nM HPU, as evaluated by the 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. As we previously reported in neutrophils, treatment with 300 nM HPU also had an anti-apoptotic effect in gastric epithelial cells leading to a 2.2-fold increase in the levels of Bcl-X_L after 6 h, and a decrease of 80% in the content of BAD, after 48 h, two mitochondrial proteins involved in regulation of apoptosis. Within 10 min of exposure, HPU is rapidly internalized by gastric epithelial cells. Treatment of the gastric cells with methyl-β-cyclodextrin abolished HPU internalization suggesting a cholesterol-dependent process. HPU induces the expression of pro-angiogenic factors and the decrease of expression of anti-angiogenic factors by AGS cells. The angiogenic activity of HPU was analyzed using in vitro and in vivo models. HPU induced formation of tube-like structures by human umbilical vascular endothelial cells in a 9 h experiment. In the chicken embryo chorioallantoic membrane model, HPU induced intense neo-vascularization after 3 days. In conclusion, our results indicate that besides allowing bacterial colonization of the gastric mucosa, H. pylori's urease triggers processes that initiate pro-angiogenic responses in different cellular models. Thus, this bacterial urease, a major virulence factor, may also play a role in gastric carcinoma development.

Angiogenesis in the atherosclerotic plaque

Atherosclerosis is a multifocal alteration of the vascular wall of medium and large arteries characterized by a local accumulation of cholesterol and non-resolving inflammation. Atherothrombotic complications are the leading cause of disability and mortality in western countries. Neovascularization in atherosclerotic lesions plays a major role in plaque growth and instability. The angiogenic process is mediated by classical angiogenic factors and by additional factors specific to atherosclerotic angiogenesis. In addition to its role in plaque progression, neovascularization may take part in plaque destabilization and thromboembolic events. Anti-angiogenic agents are effective to reduce atherosclerosis progression in various animal models. However, clinical trials with anti-angiogenic drugs, mainly anti-VEGF/VEGFR, used in anti-cancer therapy show cardiovascular adverse effects, and require additional investigations.

The Role of Mucosal Immunity in the Pathogenesis of Necrotizing Enterocolitis

Necrotizing enterocolitis (NEC) is the most devastating gastrointestinal disease of prematurity. Although the precise cause is not well understood, the main risk factors thought to contribute to NEC include prematurity, formula feeding, and bacterial colonization. Recent evidence suggests that NEC develops as a consequence of intestinal hyper-responsiveness to microbial ligands upon bacterial colonization in the preterm infant, initiating a cascade of aberrant signaling events, and a robust pro-inflammatory mucosal immune response. We now have a greater understanding of important mechanisms of disease pathogenesis, such as the role of cytokines, immunoglobulins, and immune cells in NEC. In this review, we will provide an overview of the mucosal immunity of the intestine and the relationship between components of the mucosal immune system involved in the pathogenesis of NEC, while highlighting recent advances in the field that have promise as potential therapeutic targets. First, we will describe the cellular components of the intestinal epithelium and mucosal immune system and their relationship to NEC. We will then discuss the relationship between the gut microbiota and cell signaling that underpins disease pathogenesis. We will conclude our discussion by highlighting notable therapeutic advancements in NEC that target the intestinal mucosal immunity.

Potentiation effect of HB-EGF on facilitating wound healing via 2-N,6-O-sulfated chitosan nanoparticles modified PLGA scaffold

26SCS-nanoparticles modified PLGA have synergistic effect with HB-EGF on promoting the migration of keratinocyte, realizing the skin regeneration.

Epidermal Growth Factor Rescues Endothelial Dysfunction in Primary Human Tissues In Vitro

Preeclampsia is a hypertensive disorder of pregnancy, responsible for over 60 000 maternal deaths annually. Endothelial dysfunction is a central aspect to its pathophysiology, and currently, no medical therapeutic is available for its treatment. In this study, we aim to investigate the effect of epidermal growth factor (EGF) on endothelial dysfunction using primary human tissues. We performed a number of in vitro assays that mimic the vascular endothelial dysfunction that occurs in preeclampsia. Epidermal growth factor reduced the expression of vascular cell adhesion molecule-1, a marker of endothelial dysfunction, after insult with tumor necrosis factor α (TNF-α) or serum from women with preeclampsia. Additionally, after TNF-α insult, EGF reduced tube disruption and the adhesion of monocytes to primary human umbilical vein endothelial cells (HUVECs). Our findings suggest that EGF reduces endothelial dysfunction in primary HUVECs. Epidermal growth factor may have potential as a novel peptide treatment for preeclampsia and other diseases where there is endothelial dysfunction.

Amniotic epithelial cells promote wound healing in mice through high epithelialization and engraftment

Although human amniotic epithelial cells (AMEs) are an attractive source of stem cells, their therapeutic potential in wound healing has not been fully investigated. We evaluated the therapeutic potential of AMEs for wound healing. Real-time PCR showed that the epithelialization growth factors epidermal growth factor (EGF), platelet-derived growth factor (PDGF)-B and chemotactic factors interleukin-8 (IL-8 or CXCL8) and neutrophil-activating protein-2 (NAP-2 or CXCL7) were upregulated in AMEs compared with adipose-derived mesenchymal stem cells (ADMs). In vitro scratch wound assays revealed that AME-derived conditioned medium substantially accelerated wound closure. Wounds in NOD/SCID mice were created by skin excision, followed by AME transplantation. AMEs implantation significantly accelerated wound healing and increased cellularity and re-epithelialization. Transplanted AMEs exhibited high engraftment rates and expressed keratinocyte-specific proteins and cytokeratin in the wound area, suggesting direct benefits for cutaneous closure. Taken together, these data indicate that AMEs possess therapeutic capability for wound healing through the secretion of epithelialization growth factors and enhanced engraftment properties. Copyright © 2015 John Wiley & Sons, Ltd.

Coacervate delivery of HB-EGF accelerates healing of type 2 diabetic wounds

Chronic wounds such as diabetic ulcers pose a significant challenge as a number of underlying deficiencies prevent natural healing. In pursuit of a regenerative wound therapy, we developed a heparin-based coacervate delivery system that provides controlled release of heparin-binding epidermal growth factor (EGF)-like growth factor (HB-EGF) within the wound bed. In this study, we used a polygenic type 2 diabetic mouse model to evaluate the capacity of HB-EGF coacervate to overcome the deficiencies of diabetic wound healing. In full-thickness excisional wounds on NONcNZO10 diabetic mice, HB-EGF coacervate enhanced the proliferation and migration of epidermal keratinocytes, leading to accelerated epithelialization. Furthermore, increased collagen deposition within the wound bed led to faster wound contraction and greater wound vascularization. Additionally, in vitro assays demonstrated that HB-EGF released from the coacervate successfully increased migration of diabetic human keratinocytes. The multifunctional role of HB-EGF in the healing process and its enhanced efficacy when delivered by the coacervate make it a promising therapy for diabetic wounds.

Investigation of molecular mechanisms and regulatory pathways of pro-angiogenic nanorods

Angiogenesis, a process involving the growth of new blood vessels from the pre-existing vasculature, plays a crucial role in various pathophysiological conditions. We have previously demonstrated that europium hydroxide [Eu(III)(OH)3] nanorods (EHNs) exhibit pro-angiogenic properties through the generation of reactive oxygen species (ROS) and mitogen activated protein kinase (MAPK) activation. Considering the enormous implication of angiogenesis in cardiovascular diseases (CVDs) and cancer, it is essential to understand in-depth molecular mechanisms and signaling pathways in order to develop the most efficient and effective alternative treatment strategy for CVDs. However, the exact underlying mechanism and cascade signaling pathways behind the pro-angiogenic properties exhibited by EHNs still remain unclear. Herein, we report for the first time that the hydrogen peroxide (H2O2), a redox signaling molecule, generated by these EHNs activates the endothelial nitric oxide synthase (eNOS) that promotes the nitric oxide (NO) production in a PI3K (phosphoinositide 3-kinase)/Akt dependent manner, eventually triggering angiogenesis. We intensely believe that the investigation and understanding of the in-depth molecular mechanism and signaling pathways of EHNs induced angiogenesis will help us in developing an effective alternative treatment strategy for cardiovascular related and ischemic diseases where angiogenesis plays an important role.

Heparin-binding EGF-like growth factor (HB-EGF) therapy for intestinal injury: Application and future prospects

Throughout the past 20 years, we have been investigating the potential therapeutic roles of heparin-binding EGF-like growth factor (HB-EGF), a member of the epidermal growth factor family, in various models of intestinal injury including necrotizing enterocolitis (NEC), intestinal ischemia/reperfusion (I/R) injury, and hemorrhagic shock and resuscitation (HS/R). Our studies have demonstrated that HB-EGF acts as an effective mitogen, a restitution-inducing reagent, a cellular trophic factor, an anti-apoptotic protein and a vasodilator, via its effects on various cell types in the intestine. In the current paper, we have reviewed the application and therapeutic effects of HB-EGF in three classic animal models of intestinal injury, with particular emphasis on its protection of the intestines from NEC. Additionally, we have summarized the protective functions of HB-EGF on various target cells in the intestine. Lastly, we have provided a brief discussion focusing on the future development of HB-EGF clinical applications for the treatment of various forms of intestinal injury including NEC.

Whole-body vibrations do not elevate the angiogenic stimulus when applied during resistance exercise

Knowledge about biological factors involved in exercise-induced angiogenesis is to date still scanty. The present study aimed to investigate the angiogenic stimulus of resistance exercise with and without superimposed whole-body vibrations. Responses to the exercise regimen before and after a 6-week training intervention were investigated in twenty-six healthy male subjects. Serum was collected at the initial and final exercise sessions and circulating levels of matrix metalloproteinases (MMP) -2 and -9, Vascular Endothelial Growth Factor (VEGF) and endostatin were determined via ELISA. Furthermore, we studied the proliferative effect of serum-treated human umbilical vein endothelial cells in vitro via BrdU-incorporation assay. It was found that circulating MMP-2, MMP-9, VEGF and endostatin levels were significantly elevated (P<0.001) from resting levels after both exercise interventions, with higher post-exercise VEGF concentrations in the resistance exercise (RE) group compared to the resistive vibration exercise (RVE) group. Moreover, RE provoked increased endothelial cell proliferation in vitro and higher post-exercise circulating endostatin concentrations after 6 weeks of training. These effects were elusive in the RVE group. The present findings suggest that resistance exercise leads to a transient rise in circulating angiogenic factors and superimposing vibrations to this exercise type might not further trigger a potential signaling of angiogenic stimulation in skeletal muscle.

The epidermal growth factor receptor and its ligands in cardiovascular disease

The epidermal growth factor receptor (EGFR) family and its ligands serve as a switchboard for the regulation of multiple cellular processes. While it is clear that EGFR activity is essential for normal cardiac development, its function in the vasculature and its role in cardiovascular disease are only beginning to be elucidated. In the blood vessel, endothelial cells and smooth muscle cells are both a source and a target of EGF-like ligands. Activation of EGFR has been implicated in blood pressure regulation, endothelial dysfunction, neointimal hyperplasia, atherogenesis, and cardiac remodeling. Furthermore, increased circulating EGF-like ligands may mediate accelerated vascular disease associated with chronic inflammation. Although EGFR inhibitors are currently being used clinically for the treatment of cancer, additional studies are necessary to determine whether abrogation of EGFR signaling is a potential strategy for the treatment of cardiovascular disease.

The β-blocker Nebivolol Is a GRK/β-arrestin biased agonist

Nebivolol, a third generation β-adrenoceptor (β-AR) antagonist (β-blocker), causes vasodilation by inducing nitric oxide (NO) production. The mechanism via which nebivolol induces NO production remains unknown, resulting in the genesis of much of the controversy regarding the pharmacological action of nebivolol. Carvedilol is another β-blocker that induces NO production. A prominent pharmacological mechanism of carvedilol is biased agonism that is independent of Gα_s and involves G protein-coupled receptor kinase (GRK)/β-arrestin signaling with downstream activation of the epidermal growth factor receptor (EGFR) and extracellular signal-regulated kinase (ERK). Due to the pharmacological similarities between nebivolol and carvedilol, we hypothesized that nebivolol is also a GRK/β-arrestin biased agonist. We tested this hypothesis utilizing mouse embryonic fibroblasts (MEFs) that solely express β₂-ARs, and HL-1 cardiac myocytes that express β₁- and β₂-ARs and no detectable β₃-ARs. We confirmed previous reports that nebivolol does not significantly alter cAMP levels and thus is not a classical agonist. Moreover, in both cell types, nebivolol induced rapid internalization of β-ARs indicating that nebivolol is also not a classical β-blocker. Furthermore, nebivolol treatment resulted in a time-dependent phosphorylation of ERK that was indistinguishable from carvedilol and similar in duration, but not amplitude, to isoproterenol. Nebivolol-mediated phosphorylation of ERK was sensitive to propranolol (non-selective β-AR-blocker), AG1478 (EGFR inhibitor), indicating that the signaling emanates from β-ARs and involves the EGFR. Furthermore, in MEFs, nebivolol-mediated phosphorylation of ERK was sensitive to pharmacological inhibition of GRK2 as well as siRNA knockdown of β-arrestin 1/2. Additionally, nebivolol induced redistribution of β-arrestin 2 from a diffuse staining pattern into more intense punctate spots. We conclude that nebivolol is a β₂-AR, and likely β₁-AR, GRK/β-arrestin biased agonist, which suggests that some of the unique clinically beneficial effects of nebivolol may be due to biased agonism at β₁- and/or β₂-ARs.

Low nitric oxide bioavailability upregulates renal heparin binding EGF-like growth factor expression

Decreased nitric oxide bioavailability plays an important role in the initiation and progression of diabetic nephropathy, but the underlying mechanisms remain unclear. Here, we found that heparin binding epidermal growth factor-like growth factor (HB-EGF) expression levels increased in the kidneys of both endothelial nitric oxide synthase (eNOS) knockout and eNOS knockout diabetic (Lepr db/db) mice as early as 8 weeks of age. Further increases in expression were only seen in eNOS knockout diabetic mice and paralleled the progression of glomerulopathy. HB-EGF expression increased in endothelium, podocytes, and tubular epithelial cells. In cultured glomerular endothelial cells, the nitric oxide synthase inhibitors NG-nitro-L-arginine methyl ester (L-NAME) or L-N5-(1-Iminoethyl) ornithine increased HB-EGF protein expression. Administration of L-NAME dramatically increased renal HB-EGF expression and urinary HB-EGF excretion in diabetic mice. On the other hand, replenishing nitric oxide with sodium nitrate in eNOS knockout diabetic mice reduced urinary HB-EGF excretion and inhibited the progression of diabetic nephropathy. Furthermore, specific deletion of HB-EGF expression in endothelium attenuated renal injury in diabetic eNOS knockout mice. Thus, our results suggest that decreased nitric oxide bioavailability leads to increased HB-EGF expression, which may be an important mediator of the resulting progressive diabetic nephropathy in eNOS knockout diabetic mice.

Heparin-binding EGF-like growth factor (HB-EGF) protects the intestines from radiation therapy-induced intestinal injury

PURPOSE

Radiation therapy (RT) often induces enteritis by inhibiting proliferation and inducing apoptosis. Heparin-binding EGF-like growth factor (HB-EGF) has been shown to protect the intestine in several animal injury models. The objective of this study was to examine whether HB-EGF affects RT-induced intestinal injury.

METHODS

HB-EGF or PBS was administered intraperitoneally to mice daily for 3 days, followed by total body irradiation (TBI). Three days after TBI, intestinal segments were harvested, and BrdU immunohistochemistry was performed to identify proliferating crypts (n=25). Four days after TBI, intestinal segments were harvested and assessed for histologic injury (n=34), and FITC-dextran was administered via gavage with serum FITC-dextran levels quantified to determine gut barrier function (n=18).

RESULTS

Compared to non-HB-EGF-treated irradiated mice, administration of HB-EGF to irradiated mice led to a significantly increased percentage of proliferative crypts (72.6% vs. 50.5%, p=0.001), a significantly decreased percent of histologic sections with severe histologic injury (13.7% vs. 20.3%, p=0.005), and significantly reduced intestinal permeability (18.8 μg/mL vs. 22.6 μg/mL, p=0.02).

CONCLUSIONS

These results suggest that administration of HB-EGF protects the intestines from injury after exposure to radiation therapy. Administration of HB-EGF may represent a novel therapy for the prevention of radiation enteritis in the future.

Controlled delivery of heparin-binding EGF-like growth factor yields fast and comprehensive wound healing

Wound healing is a dynamic process that relies on coordinated signaling molecules to succeed. Heparin-binding epidermal growth factor (EGF)-like growth factor (HB-EGF) is proven to accelerate healing, however precise control over its application is necessary to reduce side effects and achieve desired therapeutic benefit. To achieve effective growth factor delivery we designed a bioactive heparin-based coacervate. In vitro, HB-EGF released from the coacervate delivery system displayed enhanced bioactivity and promoted human keratinocyte migration while preserving cell proliferative capability. In a mouse excisional full-thickness wound model, controlled release of HB-EGF within the wound significantly accelerated wound closure more effectively than an equal dosage of free HB-EGF. Healing was induced by rapid re-epithelialization, granulation tissue formation, and accompanied by angiogenesis. Consistent with in vitro results, wounds treated with HB-EGF coacervate exhibited enhanced migration of keratinocytes with retained proliferative potential, forming a confluent layer for regained barrier function within 7 days. Collectively, these results suggest that coacervate-based controlled release of HB-EGF may serve as a new therapy to accelerate healing of cutaneous wounds.

Inhibition of epidermal growth factor receptor tyrosine kinase ameliorates collagen-induced arthritis

Rheumatoid arthritis (RA) is an autoimmune synovitis characterized by the formation of pannus and the destruction of cartilage and bone in the synovial joints. Although immune cells, which infiltrate the pannus and promote inflammation, play a prominent role in the pathogenesis of RA, other cell types also contribute. Proliferation of synovial fibroblasts, for example, underlies the formation of the pannus, while proliferation of endothelial cells results in neovascularization, which supports the growth of the pannus by supplying it with nutrients and oxygen. The synovial fibroblasts also promote inflammation in the synovium by producing cytokines and chemokines. Finally, osteoclasts cause the destruction of bone. In this study, we show that erlotinib, an inhibitor of the tyrosine kinase epidermal growth factor receptor (EGFR), reduces the severity of established collagen-induced arthritis, a mouse model of RA, and that it does so by targeting synovial fibroblasts, endothelial cells, and osteoclasts. Erlotinib-induced attenuation of autoimmune arthritis was associated with a reduction in number of osteoclasts and blood vessels, and erlotinib inhibited the formation of murine osteoclasts and the proliferation of human endothelial cells in vitro. Erlotinib also inhibited the proliferation and cytokine production of human synovial fibroblasts in vitro. Moreover, EGFR was highly expressed and activated in the synovium of mice with collagen-induced arthritis and patients with RA. Taken together, these findings suggest that EGFR plays a central role in the pathogenesis of RA and that EGFR inhibition may provide benefits in the treatment of RA.

HB-EGF improves intestinal microcirculation after hemorrhagic shock

BACKGROUND

The goal of this study was to determine the role of heparin-binding epidermal growth factor-like growth factor (HB-EGF) as a mediator of gut microcirculation after hemorrhagic shock and resuscitation (HS/R) in mice.

MATERIALS AND METHODS

HS/R was induced in HB-EGF knockout (KO) and wild type (WT) mice. Ink-gelatin injection and vascular corrosion casting were performed to visualize the gut microvasculature. The degree of gut microcirculatory injury was graded using five patterns of injury (1-5) according to the severity of microvascular hypoperfusion. Statistical analyses were performed using linear mixed models with P < 0.05 considered statistically significant.

RESULTS

HB-EGF KO mice subjected to HS/R had significantly decreased perfusion of the gut microvasculature compared with WT mice subjected to HS/R (P = 0.0001). HB-EGF KO mice subjected to HS/R and treated with exogenous HB-EGF had significantly increased gut microvascular perfusion compared with non-HB-EGF treated KO mice (P = 0.01). Lastly, WT mice subjected to HS/R and treated with HB-EGF had significantly increased gut microvascular perfusion compared with non-HB-EGF-treated WT mice (P = 0.04).

CONCLUSIONS

HB-EGF improves gut microcirculation after HS/R. These findings support the clinical use of HB-EGF in protection of the intestines from disease states associated with intestinal hypoperfusion injury.

A pharmacological primer of biased agonism

Biased agonism is one of the fastest growing topics in G protein-coupled receptor pharmacology; moreover, biased agonists are used in the clinic today: carvedilol (Coreg^®) is a biased agonist of beta-adrenergic receptors. However, there is a general lack of understanding of biased agonism when compared to traditional pharmacological terminology. Therefore, this review is designed to provide a basic introduction to classical pharmacology as well as G protein-coupled receptor signal transduction in order to clearly explain biased agonism for the non-scientist clinician and pharmacist. Special emphasis is placed on biased agonists of the beta-adrenergic receptors, as these drugs are highly prescribed, and a hypothetical scenario based on current clinical practices and proposed mechanisms for treating disease is discussed in order to demonstrate the need for a more thorough understanding of biased agonism in clinical settings. Since biased agonism provides a novel mechanism for treating disease, greater emphasis is being placed to develop biased agonists; therefore, it is important for biased agonism to be understood in equal measure of traditional pharmacological concepts. This review, along with many others, can be used to teach the basic concepts of biased agonism, and this review also serves to introduce the subsequent reviews that examine, in more depth, the relevance of biased agonism towards the angiotensin type 1 receptor, parathyroid hormone receptor, and natural biased ligands towards chemokine receptors.

Gene expression analysis of ischaemia and reperfusion in human microsurgical free muscle tissue transfer

The aim of this study was to analyse various gene expression profiles of muscle tissue during normoxia, ischaemia and after reperfusion in human muscle free flaps, to gain an understanding of the occurring regulatory, inflammatory and apoptotic processes on a cellular and molecular basis. Eleven Caucasian patients with soft tissue defects needing coverage with microsurgical free muscle flaps were included in this study. In all patients, the muscle samples were taken from free myocutaneous flaps. The first sample was taken before induction of ischaemia in normoxia (I), another one after ischaemia (II), and the last one was taken after reperfusion (III). The samples were analysed using DNA-microarray, real-time-quantitative-PCR and immunohistochemistry. DNA-microarray analysis detected multiple, differentially regulated genes when comparing the different groups (I–III) with statistical significance. Comparing ischaemia (II) versus normoxia (I) educed 13 genes and comparing reperfusion (III) versus ischaemia (II) educed 19 genes. The comparison of reperfusion (III) versus normoxia (I) yielded 100 differentially regulated genes. Real-time-quantitative-PCR confirmed the results of the DNA-microarrays for a subset of four genes (CASP8, IL8, PLAUR and S100A8). This study shows that ischaemia and reperfusion induces alterations on the gene expression level in human muscle free flaps. Data may suggest that the four genes CASP8, IL8, PLAUR and S100A8 are of great importance in this context. We could not confirm the DNA-microarry and real-time-quantitative-PCR results on the protein level. Finally, these findings correspond with the surgeon’s clinical experience that the accepted times of ischaemia, generally up to 90 min., are not sufficient to induce pathophysiological processes, which can ultimately lead to flap loss. When inflammatory and apoptotic proteins are expressed at high levels, flap damage might occur and flap loss is likely. The sole expression on mRNA level might explain why flap loss is unlikely.

IL-8-mediated angiogenic responses of endothelial cells to lipid antigen activation of iNKT cells depend on EGFR transactivation

iNKT cells are a unique T cell subset, which is CD1d-restricted and specific for glycolipid antigens. In advanced atherosclerotic plaques, focal collections of inflammatory cells correlate with areas of intraplaque neovascularization. We reported recently that iNKT cells might facilitate intraplaque neovascularization by enhancing EC migration and sprouting in an IL-8-dependent manner. This study investigated the participating effector mechanisms. In ECs, CM, derived from antigen-stimulated human iNKT cells (CM+), induced up-regulation of IL-8R CXCR2 and the phosphorylation of EGFR and of multiple intracellular signaling effectors, including FAK, Src, Erk, Jnk, p38-MAPK, and STAT1 and -3. We found that a cascade of events, which were IL-8-dependent and involved EGFR activation, was responsible for signaling through FAK and Src kinases and necessary for acquisition of angiogenic morphology, migration in a two-dimensional wound assay, and sprout outgrowth in a three-dimensional model of angiogenesis in vitro. The data support that IL-8-dependent activation of angiogenic behavior in ECs, in response to activated iNKT, involves CXCR2, transactivation of EGFR, and subsequent FAK/Src signaling. We found too that activated iNKT increased VEGFR2 expression in ECs. Functional studies confirmed that EGF is the motogenic-enhancing factor in CM+ and is necessary, together with an exogenous source of VEGF, for iNKT-promoted sprout formation. EGFR inhibition may represent a novel therapeutic modality aimed at plaque stabilization through control of neovascularization within developing atherosclerotic plaques.

Membrane receptor for thyroid hormone: physiologic and pharmacologic implications

Plasma membrane integrin αvβ3 is a cell surface receptor for thyroid hormone at which nongenomic actions are initiated. L-thyroxine (T₄) and 3,3',5-triiodo-L-thyronine (T₃) promote angiogenesis and tumor cell proliferation via the receptor. Tetraiodothyroacetic acid (tetrac), a deaminated T₄ derivative, blocks the nongenomic proliferative and proangiogenic actions of T₄ and T₃. Acting at the integrin independently of T₄ and T₃, tetrac and a novel nanoparticulate formulation of tetrac that acts exclusively at the cell surface have oncologically desirable antiproliferative actions on multiple tumor cell survival pathway genes. These agents also block the angiogenic activity of vascular growth factors. Volume and vascular support of xenografts of human pancreatic, kidney, lung, and breast cancers are downregulated by tetrac formulations. The integrin αvβ3 receptor site for thyroid hormone selectively regulates signal transduction pathways and distinguishes between unmodified tetrac and the nanoparticulate formulation. The receptor also mediates nongenomic thyroid hormone effects on plasma membrane ion transporters and on intracellular protein trafficking.

Endothelial NOS-derived nitric oxide prevents injury resulting from reoxygenation in the hypoxic lung

To date, the role that NO derived from endothelial NO synthase (eNOS) plays in the development of the injuries occurring under hypoxia/reoxygenation (H/R) in the lung remains unknown and thus constitutes the subject of the present work. A follow-up study was conducted in Wistar rats submitted to H/R (hypoxia for 30 min; reoxygenation of 0 h, 48 h and 5 days), with or without prior treatment using the eNOS inhibitor L-NIO (20 mg/kg). Lipid peroxidation, apoptosis, protein nitration and NO production (NOx) were analysed. The results showed that L-NIO administration lowered NOx levels in all the experimental groups. Contrarily, the lipid peroxidation level and the percentage of apoptotic cells rose, implying that eNOS-derived NO may have a protective effect against the injuries occurring during H/R in the lung. These findings could open the possibility of future studies to design new therapies for this type of hypoxia based on NO-pharmacology.

Mice overexpressing the gene for heparin-binding epidermal growth factor-like growth factor (HB-EGF) have increased resistance to hemorrhagic shock and resuscitation

BACKGROUND

The aim of the current study was to determine whether overexpression of heparin-binding epidermal growth factor-like growth factor (HB-EGF) could protect the intestines from injury after hemorrhagic shock and resuscitation in mice.

METHODS

Hemorrhagic shock and resuscitation was induced in HB-EGF transgenic and wild type mice. Cross-reacting material 197 (5 mg/kg) was administered to a subset of HB-EGF transgenic mice to block the overexpressed HB-EGF. Intestinal histologic injury scores, intestinal epithelial cell apoptosis indices, and gut barrier function were determined. The Student t test and 1-way analysis of variance were employed to compare the differences between groups.

RESULTS

All mice subjected to hemorrhagic shock and resuscitation had significantly increased intestinal histologic injury scores, apoptosis indices, and intestinal permeability compared with sham-operated mice. Compared with wild type mice, HB-EGF transgenic mice had significantly decreased histologic injury (mean injury grade 2.79 ± 0.84 vs 3.88 ± 1.43, P = .02), apoptosis indices (mean apoptosis index 8.77 ± 5.23 vs 17.91 ± 13.23, P = .03), and mucosal permeability (FITC-dextran 4 clearance 13.06 ± 5.67 vs 20.03 ± 7.81 nL/min/ m(2), P = .02) at 3 hours of reperfusion. HB-EGF transgenic mice subjected to hemorrhagic shock and resuscitation and treated with cross-reacting material 197 had a significantly increased histologic injury (mean injury grade 3.63 ± 1.00 vs 2.79 ± 0.84, P = .04) and mucosal permeability (FITC-dextran 4 clearance 22.87 ± 9.69 vs 13.06 ± 5.67 nL/min/cm2, P = .01) at 3 hours of reperfusion compared with non-cross-reacting material 197 treated transgenic mice, with no significant changes in apoptosis indices. Cross-reacting material 197 did not reverse the decreased apoptosis observed in HB-EGF transgenic mice subjected to hemorrhagic shock and resuscitation, which suggests that mechanisms in addition to decreased apoptosis may be responsible for the intestinal cytoprotective effects of endogenous HB-EGF overexpression.

CONCLUSION

Overexpression of HB-EGF increases resistance to hemorrhagic shock and resuscitation in mice.

Heparin-binding EGF-like growth factor protects pericytes from injury

BACKGROUND

We have previously shown that heparin-binding EGF-like growth factor (HB-EGF) promotes angiogenesis and preserves mesenteric microvascular blood flow in several models of intestinal injury. The current study was designed to evaluate the effect of HB-EGF on pericytes, since these cells function to regulate capillary blood flow and new capillary growth.

MATERIALS AND METHODS

C3H/10T1/2 mouse mesenchymal cells were differentiated into pericyte-like cells in vitro using transforming growth factor-β1 (TGF-β1). In addition, primary pericyte cultures were established from rat brain. The effect of HB-EGF on pericyte proliferation was assessed. In addition, cells were stressed by exposure to anoxia, and apoptosis determined. In vivo, we examined the effect of HB-EGF on pericytes in a model of intestinal I/R injury based on superior mesenteric artery occlusion (SMAO) in mice.

RESULTS

Differentiated C3H/10T1/2 cells (pericyte-like cells) demonstrated morphologic characteristics of pericytes, and expressed pericyte specific markers. Addition of HB-EGF led to significant cell proliferation in differentiated pericyte-like cells, even under conditions of anoxic stress. Addition of the EGF receptor inhibitor AG 1478 led to complete inhibition of the proliferative effects of HB-EGF on pericyte-like cells. In addition, HB-EGF protected pericyte-like cells from anoxia-induced apoptosis. In addition, HB-EGF promoted cell proliferation in primary pericyte cultures. In vivo, administration of HB-EGF to mice subjected to intestinal I/R injury led to protection of pericytes from injury.

CONCLUSIONS

These results suggest that HB-EGF may function as a microcirculatory blood flow regulator, at least in part, via its effects on pericytes.

Heparin-binding EGF-like growth factor promotes intestinal anastomotic healing

BACKGROUND

We have accumulated multiple lines of evidence supporting the ability of HB-EGF to protect the intestines from injury and to augment the healing of partial-thickness scald burns of the skin. The aim of the current study was to investigate the role of heparin-binding EGF-like growth factor (HB-EGF) in intestinal anastomotic wound healing.

MATERIALS AND METHODS

HB-EGF (-/-) knockout (KO) mice (n=42) and their HB-EGF (+/+) wild type (WT) counterparts (n=33), as well as HB-EGF transgenic (TG) mice (n=26) and their (WT) counterparts (n=27), underwent division and reanastomosis of the terminal ileum. In addition, WT mice (n=21) that received enteral HB-EGF (800 μg/kg) underwent the same operative procedure. Anastomotic bursting pressure was measured at 3 and 6 d postoperatively. Tissue sections were stained with hematoxylin and eosin to assess anastomotic healing, and Picrosirus red to assess collagen deposition. Immunohistochemistry using anti-von Willebrand factor antibodies was performed to assess angiogenesis. Complications and mortality were also recorded.

RESULTS

HB-EGF KO mice had significantly lower bursting pressures, lower healing scores, higher mortality, and higher complication rates postoperatively compared with WT mice. Collagen deposition and angiogenesis were significantly decreased in KO mice compared with WT mice. Conversely, HB-EGF TG mice had increased anastomotic bursting pressure, higher healing scores, lower mortality, lower complication rates, increased collagen deposition, and increased angiogenesis postoperatively compared with WT mice. WT mice that received HB-EGF had increased bursting pressures compared with non-HB-EGF treated mice.

CONCLUSION

Our results demonstrate that HB-EGF is an important factor involved in the healing of intestinal anastomoses.

Melatonin promotes angiogenesis during protection and healing of indomethacin-induced gastric ulcer: role of matrix metaloproteinase-2

Matrix metalloproteinase (MMP)-2 is considered as a crucial regulator of angiogenesis, a process of new blood vessel formation. We reported previously that melatonin (N-acetyl-5-methoxy tryptamine), an antioxidant and anti-inflammatory agent, prevents indomethacin-induced gastric ulcers. Herein, we investigated the effect of melatonin on MMP-2-mediated angiogenesis during gastroprotection. Angiogenic properties of melatonin were tested in both rat corneal micropocket assay and in mouse model of indomethacin-induced gastric lesions. Melatonin augmented angiogenesis that was associated with amelioration of MMP-2 expression and activity and, upregulation of vascular endothelial growth factor (VEGF) in rat cornea. Melatonin prevented gastric lesions by promoting angiogenesis via upregulation of VEGF followed by over-expression of MMP-2. Similarly, healing of gastric lesions was associated with early expression of VEGF followed by MMP-2. In addition, upregulation of MMP-2 was parallel to MMP-14 and inverse to tissue inhibitor of metalloprotease (TIMP)-2 expression during gastroprotection. Our data demonstrated that melatonin exerts angiogenesis through MMP-2 and VEGF over-expression during protection and healing of gastric ulcers. This study highlights for the first time a phase-associated regulation of MMP-2 activity in gastric mucosa and an angiogenic action of melatonin to rescue indomethacin-induced gastropathy.

Epidermal growth factor receptor signaling modulates chemokine (CXC) ligand 5 expression and is associated with villus angiogenesis after small bowel resection

BACKGROUND

Adaptive villus growth after a massive small bowel resection (SBR) is an important response to the loss of intestinal surface area and is regulated via epidermal growth factor receptor (EGFR) signaling. Increased levels of the proangiogenic chemokine ligand 5 (CXCL5) have been found within the adapting bowel in which angiogenesis is increased. We sought to determine whether CXCL5 was expressed specifically in the villus mesenchymal zone (area of increased blood vessel growth) and whether this expression was affected by EGF.

METHODS

C57BL/6J mice were subjected to sham operation (bowel transaction with reanastomosis) or 50% proximal SBR. The remnant intestine was harvested, and the villus lamina propria was isolated by laser capture microdissection. The expression of CXCL5 messenger RNA (mRNA) was analyzed using real-time polymerase chain reaction (RT-PCR). Furthermore, CXCL5 mRNA levels were determined in EGF-stimulated human umbilical vein endothelial cells (HUVECs).

RESULTS

A 2.39-fold increase (P < .05) in CXCL5 mRNA occurred in the lamina propria after SBR. In addition, villus height was found to be related directly to the degree of CXCL5 mRNA (R(2) = 0.97) expression. HUVECs treated with EGF demonstrated a 9-fold increase in CXCL5 mRNA expression.

CONCLUSION

The villus growth observed in resection-induced adaptation is associated with increased expression of the chemokine CXCL5 within the lamina propria. Because EGF enhances CXCL5 expression directly in endothelial cells, EGFR-directed proangiogenic gene expression may be a critical mechanism for adaptive ileal villus growth.