Vascular endothelial growth factor blockade reduces plasma cytokines in a murine model of polymicrobial sepsis

Is there a place for natural agents with anti-inflammatory and antioxidative properties in critically ill patients? Potential usefulness of Xanthohumol

Multi-organ dysfunction is a major issue in critically ill patients, where a significant inflammatory response appears to be the primary factor driving the degree of organ impairment, which correlates with the extent of organ injury. The management of inflammation requires a multidisciplinary approach, including antibiotics for infection control, circulatory and respiratory support, and correction of coagulation abnormalities. However, the use of anti-inflammatory treatments is typically restricted to a selected group of medications, with their effectiveness remaining the subject of extensive debate. Xanthohumol (Xn), a natural compound extracted from hops, possesses strong anti-inflammatory and antioxidative properties, with a mild anti-coagulation effect. Its biological activity is related to the inhibition of different inflammatory pathways, reduction in cytokine production and secretion, and an increase in antioxidative enzyme activity. This review examined the potential use of Xn as an adjuvant in the treatment of various pathologies in critically ill patients.

Endothelial dysfunction: Pathophysiology and therapeutic targets for sepsis-induced multiple organ dysfunction syndrome

Sepsis and septic shock are critical medical conditions characterized by a systemic inflammatory response to infection, significantly contributing to global mortality rates. The progression to multiple organ dysfunction syndrome (MODS) represents the most severe complication of sepsis and markedly increases clinical mortality. Central to the pathophysiology of sepsis, endothelial cells play a crucial role in regulating microcirculation and maintaining barrier integrity across various organs and tissues. Recent studies have underscored the pivotal role of endothelial function in the development of sepsis-induced MODS. This review aims to provide a comprehensive overview of the pathophysiology of sepsis-induced MODS, with a specific focus on endothelial dysfunction. It also compiles compelling evidence regarding potential small molecules that could attenuate sepsis and subsequent multi-organ damage by modulating endothelial function. Thus, this review serves as an essential resource for clinical practitioners involved in the diagnosing, managing, and providing intensive care for sepsis and associated multi-organ injuries, emphasizing the importance of targeting endothelial cells to enhance outcomes of the patients.

Endothelial Cell Dysfunction Due to Molecules Secreted by Macrophages in Sepsis

Sepsis is recognized as a syndrome of systemic inflammatory reaction induced by dysregulation of the body's immunity against infection. The multiple organ dysfunction associated with sepsis is a serious threat to the patient's life. Endothelial cell dysfunction has been extensively studied in sepsis. However, the role of macrophages in sepsis is not well understood and the intrinsic link between the two cells has not been elucidated. Macrophages are first-line cells of the immune response, whereas endothelial cells are a class of cells that are highly altered in function and morphology. In sepsis, various cytokines secreted by macrophages and endothelial cell dysfunction are inextricably linked. Therefore, investigating how macrophages affect endothelial cells could offer a theoretical foundation for the treatment of sepsis. This review links molecules (TNF-α, CCL2, ROS, VEGF, MMP-9, and NO) secreted by macrophages under inflammatory conditions to endothelial cell dysfunction (adhesion, permeability, and coagulability), refining the pathophysiologic mechanisms of sepsis. At the same time, multiple approaches (a variety of miRNA and medicines) regulating macrophage polarization are also summarized, providing new insights into reversing endothelial cell dysfunction and improving the outcome of sepsis treatment.

Potential of piperine for neuroprotection in sepsis-associated encephalopathy

AIMS

Sepsis-associated encephalopathy (SAE) is a common complication that increases mortality and leads to long-term cognitive impairment in sepsis survivors. However, no specific or effective therapy has been identified for this complication. Piperine is an alkaloid known for its anti-inflammatory, antioxidant, and neuroprotective properties, which are important characteristics for treatment of SAE. The objective of this study was to evaluate the neuroprotective effect of piperine on SAE in C57BL/6 mice that underwent cecum ligation and perforation surgery (CLP).

MAIN METHODS

C57BL/6 male mice were randomly assigned to groups that underwent SHAM surgery or CLP. Mice in the CLP group were treated with piperine at doses of 20 or 40 mg/kg for short- (5 days) or long-term (10 days) periods after CLP.

KEY FINDINGS

Our results revealed that untreated septic animals exhibited increased concentrations of IL-6, TNF, VEGF, MMP-9, TBARS, and NLRP3, and decreased levels of BDNF, sulfhydryl groups, and catalase in the short term. Additionally, the levels of carbonylated proteins and degenerated neuronal cells were increased at both time points. Furthermore, short-term and visuospatial memories were impaired. Piperine treatment reduced MMP-9 activity in the short term and decreased the levels of carbonylated proteins and degenerated neuronal cells in the long term. It also lowered IL-6 and TBARS levels at both time points evaluated. Moreover, piperine increased short-term catalase and long-term BDNF factor levels and improved memory at both time points.

SIGNIFICANCE

In conclusion, our data demonstrate that piperine exerts a neuroprotective effect on SAE in animals that have undergone CLP.

Combined glucocorticoid resistance and hyperlactatemia contributes to lethal shock in sepsis

Sepsis is a potentially lethal syndrome resulting from a maladaptive response to infection. Upon infection, glucocorticoids are produced as a part of the compensatory response to tolerate sepsis. This tolerance is, however, mitigated in sepsis due to a quickly induced glucocorticoid resistance at the level of the glucocorticoid receptor. Here, we show that defects in the glucocorticoid receptor signaling pathway aggravate sepsis pathophysiology by lowering lactate clearance and sensitizing mice to lactate-induced toxicity. The latter is exerted via an uncontrolled production of vascular endothelial growth factor, resulting in vascular leakage and collapse with severe hypotension, organ damage, and death, all being typical features of a lethal form of sepsis. In conclusion, sepsis leads to glucocorticoid receptor failure and hyperlactatemia, which collectively leads to a lethal vascular collapse.

Zinc Finger Protein St18 Protects against Septic Death by Inhibiting VEGF-A from Macrophages

Zinc finger protein St18 was initially reported as candidate tumor suppressor gene, and also suggested that fibroblast St18 positively regulates NF-κB activation. Despite the pleiotropic functions of St18, little is known about its roles in macrophages. Here, we report that myeloid St18 is a potent inhibitor of VEGF-A. Mice lacking St18 in myeloid lineages exhibit increased retinal vasculature with enhanced serum VEGF-A concentrations. Despite the normal activation of NF-κB target genes, these mice are highly susceptible to LPS-induced shock, polymicrobial sepsis, and experimental colitis, accompanied by enhanced vascular and intestinal leakage. Pharmacological inhibition of VEGF signaling rescued the high mortality rate of myeloid-specific St18-deficient mice in response to inflammation. Mechanistically, St18 directly binds to Sp1 and attenuates its activity, leading to the suppression of Sp1 target gene VEGF-A. Using mouse genetic and pharmacological models, we reveal myeloid St18 as a critical septic death protector.

Therapeutic Potential of Rhododendron arboreum Polysaccharides in an Animal Model of Lipopolysaccharide-Inflicted Oxidative Stress and Systemic Inflammation

Systemic inflammation results in physiological changes, largely mediated by inflammatory cytokines. The present investigation was performed to determine the effect of Rhododendron arboreum (RAP) on inflammatory parameters in the animal model. The RAP (100 and 200 mg/kg) were pre-treated for animals, given orally for one week, followed by lipopolysaccharide (LPS) injection. Body temperature, burrowing, and open field behavioral changes were assessed. Biochemical parameters (AST, ALT, LDH, BIL, CK, Cr, BUN, and albumin) were done in the plasma after 6 h of LPS challenge. Oxidative stress markers SOD, CAT, and MDA were measured in different organs. Levels of inflammatory markers like tumor necrosis factor-alpha (TNF-α), interleukin-1-beta (IL-1β) and, interleukin-6 (IL-6) as well as VEGF, a specific sepsis marker in plasma, were quantified. The plasma enzymes, antioxidant markers and plasma pro-inflammatory cytokines were significantly restored (p < 0.5) by RAP treatment, thus preventing the multi-organ and tissue damage in LPS induced rats. The protective effect of RAP may be due to its potent antioxidant potential. Thus, RAP can prevent LPS induced oxidative stress, as well as inflammatory and multi-organ damage as reported in histopathological studies in rats when administered to the LPS treated animals. These findings indicate that RAP can benefit in the management of systemic inflammation from LPS and may have implications for a new treatment or preventive therapeutic strategies with an inflammatory component.

Multiomics of World Trade Center Particulate Matter-induced Persistent Airway Hyperreactivity. Role of Receptor for Advanced Glycation End Products

Pulmonary disease after World Trade Center particulate matter (WTC-PM) exposure is associated with dyslipidemia and the receptor for advanced glycation end products (RAGE); however, the mechanisms are not well understood. We used a murine model and a multiomics assessment to understand the role of RAGE in the pulmonary long-term effects of a single high-intensity exposure to WTC-PM. After 1 month, WTC-PM-exposed wild-type (WT) mice had airway hyperreactivity, whereas RAGE-deficient (Ager^-/-) mice were protected. PM-exposed WT mice also had histologic evidence of airspace disease, whereas Ager^-/- mice remained unchanged. Inflammatory mediators such as G-CSF (granulocyte colony-stimulating factor), IP-10 (IFN-γ-induced protein 10), and KC (keratinocyte chemoattractant) were differentially expressed after WTC-PM exposure. WTC-PM induced α-SMA, DIAPH1 (protein diaphanous homolog 1), RAGE, and significant lung collagen deposition in WT compared with Ager^-/- mice. Compared with WT mice with PM exposure, relative expression of phosphorylated to total CREB (cAMP response element-binding protein) and JNK (c-Jun N-terminal kinase) was significantly increased in the lung of PM-exposed Ager^-/- mice, whereas Akt (protein kinase B) was decreased. Random forests of the refined lung metabolomic profile classified subjects with 92% accuracy; principal component analysis captured 86.7% of the variance in three components and demonstrated prominent subpathway involvement, including known mediators of lung disease such as vitamin B₆ metabolites, sphingolipids, fatty acids, and phosphatidylcholines. Treatment with a partial RAGE antagonist, pioglitazone, yielded similar fold-change expression of metabolites (N₆-carboxymethyllysine, 1-methylnicotinamide, N¹+N⁸-acetylspermidine, and succinylcarnitine [C4-DC]) between WT and Ager^-/- mice exposed to WTC-PM. RAGE can mediate WTC-PM-induced airway hyperreactivity and warrants further investigation.

Dual Pharmacological Inhibition of Angiopoietin-2 and VEGF-A in Murine Experimental Sepsis

BACKGROUND

Sepsis is a pathological host response to infection leading to vascular barrier breakdown due to elevated levels of angiopoietin-2 (Angpt-2) and vascular endothelial growth factor-A (VEGF-A). Here, we tested a novel heterodimeric bispecific monoclonal IgG1-cross antibody of Angpt-2 and VEGF - termed "A2V."

METHODS

Cecal ligation and puncture was used to induce murine polymicrobial sepsis. Organs and blood were harvested for fluorescence immunohistochemistry and RT-PCR, and survival was recorded. In vitro endothelial cells were stimulated with plasma from septic shock patients costimulated with A2V or IgG antibody followed by immunocytochemistry and real-time transendothelial electrical resistance.

RESULTS

Septic mice treated with A2V had a reduced induction of the endothelial adhesion molecule ICAM-1, leading to a trend towards less transmigration of inflammatory cells (A2V: 42.2 ± 1.0 vs. IgG 48.5 ± 1.7 Gr-1+ cells/HPF, p = 0.08) and reduced tissue levels of inflammatory cytokines (e.g., IL-6 mRNA: A2V 9.4 ± 3.2 vs. IgG 83.9 ± 36.7-fold over control, p = 0.03). Endothelial permeability was improved in vivo and in vitro in stimulated endothelial cells with septic plasma. Survival was improved by 38% (p = 0.02).

CONCLUSION

Dual inhibition of Angpt-2 and VEGF-A improves murine sepsis morbidity and mortality, making it a potential therapeutic against vascular barrier breakdown.

Resveratrol alleviates sepsis-induced acute lung injury by suppressing inflammation and apoptosis of alveolar macrophage cells

Sepsis is a major cause of death in intensive care units. The purpose of this study was to investigate the effect of resveratrol (RSV) on sepsis-induced acute lung injury (ALI). The underlying molecular mechanisms were deciphered by both in vitro and in vivo experiments. Polymicrobial sepsis was induced in C57BL/6 mice by cecal ligation and puncture (CLP). RSV pretreatment significantly attenuated CLP-induced acute lung injury, which was associated with enhanced expression of VEGF-B. The protective properties of RSV were assayed in lipopolysaccharide (LPS)-stimulated MH-S cells. We determine that RSV administration inhibited the increased production of TNF-α, IL-6, and IL-1β in LPS-stimulated MH-S cells, which was associated with inhibition of the nuclear factor-κB, P38, and ERK signaling pathways. We also provide evidence that RSV administration reduced LPS-induced apoptosis of MH-S cells by altering the unbalance of Bax/Bcl-2 and inhibiting LPS-induced autophagy. The inhibitory effects of RSV on cytokine levels and apoptosis of alveolar macrophages were both blocked by VEGF-B siRNA. Furthermore, RSV administration regulated LPS-induced C5aR and C5L2 expression, revealing an additional mechanism underlying RSV's anti-inflammatory and anti-apoptosis effects. Collectively, these results demonstrated that RSV was able to protect against sepsis-induced acute lung injury by activating the VEGF-B signaling pathway.

Receptor for advanced glycation end-products and World Trade Center particulate induced lung function loss: A case-cohort study and murine model of acute particulate exposure

World Trade Center-particulate matter(WTC-PM) exposure and metabolic-risk are associated with WTC-Lung Injury(WTC-LI). The receptor for advanced glycation end-products (RAGE) is most highly expressed in the lung, mediates metabolic risk, and single-nucleotide polymorphisms at the AGER-locus predict forced expiratory volume(FEV). Our objectives were to test the hypotheses that RAGE is a biomarker of WTC-LI in the FDNY-cohort and that loss of RAGE in a murine model would protect against acute PM-induced lung disease. We know from previous work that early intense exposure at the time of the WTC collapse was most predictive of WTC-LI therefore we utilized a murine model of intense acute PM-exposure to determine if loss of RAGE is protective and to identify signaling/cytokine intermediates. This study builds on a continuing effort to identify serum biomarkers that predict the development of WTC-LI. A case-cohort design was used to analyze a focused cohort of male never-smokers with normal pre-9/11 lung function. Odds of developing WTC-LI increased by 1.2, 1.8 and 1.0 in firefighters with soluble RAGE (sRAGE)≥97pg/mL, CRP≥2.4mg/L, and MMP-9≤397ng/mL, respectively, assessed in a multivariate logistic regression model (ROCAUC of 0.72). Wild type(WT) and RAGE-deficient(Ager-/-) mice were exposed to PM or PBS-control by oropharyngeal aspiration. Lung function, airway hyperreactivity, bronchoalveolar lavage, histology, transcription factors and plasma/BAL cytokines were quantified. WT-PM mice had decreased FEV and compliance, and increased airway resistance and methacholine reactivity after 24-hours. Decreased IFN-γ and increased LPA were observed in WT-PM mice; similar findings have been reported for firefighters who eventually develop WTC-LI. In the murine model, lack of RAGE was protective from loss of lung function and airway hyperreactivity and was associated with modulation of MAP kinases. We conclude that in a multivariate adjusted model increased sRAGE is associated with WTC-LI. In our murine model, absence of RAGE mitigated acute deleterious effects of PM and may be a biologically plausible mediator of PM-related lung disease.

Modulating sphingosine 1-phosphate signaling with DOP or FTY720 alleviates vascular and immune defects in mouse sepsis

Sepsis is a systemic inflammatory response to pathogens and a leading cause of hospital related mortality worldwide. Sphingosine 1-phosphate (S1P) regulates multiple cellular processes potentially involved in the pathogenesis of sepsis, including antigen presentation, lymphocyte egress, and maintenance of vascular integrity. We thus explored the impact of manipulating S1P signaling in experimental polymicrobial sepsis in mice. Administration of 4-deoxypyridoxine (DOP), an inhibitor of the S1P-degrading enzyme S1P-lyase, or of the sphingosine analog FTY720 that serves as an S1P receptor agonist after phosphorylation ameliorated morbidity, improved recovery from sepsis in surviving mice, and reduced sepsis-elicited hypothermia and body weight loss. Treated mice developed lymphopenia, leading to an accumulation of lymphocytes in peripheral lymph nodes, and reduced bacterial burden in liver, but not in blood. Sepsis-induced upregulation of mRNA expression of cytokines in spleen remained unchanged, but reduction of IL-6, TNF-α, MCP-1, and IL-10 in plasma was evident. DOP and FTY720 treatment significantly reduced levels of Evans blue leakage from blood into liver and lung, decreased hematocrit values, and lowered plasma levels of VEGF-A in septic mice. Collectively, our results indicate that modulation of S1P signaling showed a protective phenotype in experimental sepsis by modulating vascular and immune functions.

C/EBP β mRNA expression is upregulated and positively correlated with the expression of TNIP1/TNFAIP3 in peripheral blood mononuclear cells from patients with systemic lupus erythematosus

CCAAT/enhancer-binding protein β (C/EBP β) has important roles in numerous signaling pathways. The expression of the majority of regulators and target gene products of C/EBP β, including tumor necrosis factor α-induced protein 3 (TNFAIP3) and TNFAIP3-interacting protein 1 (TNIP1), are upregulated in patients with systemic lupus erythematosus (SLE). The aim of the present study was to investigate whether C/EBP β expression is associated with SLE pathogenesis and correlates with TNIP1 and TNFAIP3 expression. Quantitative reverse transcription-polymerase chain reaction analysis was used to assess the expression of C/EBP β, TNIP1, and TNFAIP3 mRNA in peripheral blood mononuclear cells (PBMC) from 20 patients with SLE and 20 healthy controls. Spearman's rank test was used to determine the correlation between C/EBP β expression and SLE disease activity, and that between C/EBP β expression and TNIP1/TNFAIP3 expression in PBMCs from patients with SLE. C/EBP β mRNA expression was markedly increased in patients with SLE compared with healthy controls. The expression of C/EBP β was positively correlated with the SLE disease activity index and negatively correlated with the serum level of complement components C3 and C4. In addition, C/EBP β mRNA expression was increased in PBMCs from SLE patients that were positive for antinuclear, anti-Smith and anti-nRNP antibodies, compared with the antibody negative SLE patients. Furthermore, the mRNA expression levels of C/EBP β in patients with SLE was positively correlated with TNIP1 and TNFAIP3 expression. The results of the current study suggest that the increased expression of C/EBP β in PBMCs and the interaction between C/EBP β and TNIP1/TNFAIP3 may be involved in the pathogenesis of SLE.

Combined treatment in punctate inner choroidopathy

Purpose

The purpose of this study was to describe a combination treatment for choroidal neovascular (CNV) membrane, secondary to punctate inner choroidopathy (PIC).

Patient and methods

A 44-year-old female patient was diagnosed with PIC complicated by the development of recurrent juxtafoveal neovascular membrane. The treatment included a sequence of monotherapy regimens: systemic steroid therapy, photodynamic therapy, and intravitreal injections of vascular endothelial growth factor (VEGF) inhibitor (anti-VEGF). Owing to the CNV membrane resistance to various types of monotherapy, a combination treatment consisting of local injections of steroid underneath the Tenon’s capsule and intravitreal anti-VEGF injections was used.

Results

Systemic steroid therapy resulted in rapid local improvement with a very short remission period. No positive effects of photodynamic therapy were observed. Sequential anti-VEGF injections led to remission periods of several months. Permanent regression of CNV membrane was achieved following combined local application of steroid and intravitreal anti-VEGF injections.

Conclusion

A combination treatment including steroid and anti-VEGF medication characterized by anti-inflammatory and antiangiogenic effects may be a very beneficial option for the treatment of recurrent CNV membrane as a complication of PIC.

Protective effects of rutin through regulation of vascular endothelial growth factor in allergic rhinitis

BACKGROUND

Allergic rhinitis (AR) is an allergic inflammatory disease induced by various mediators released by infiltrating inflammatory cells. Vascular endothelial growth factor (VEGF) increases the airway inflammatory response by promoting vascular permeability. Furthermore, it is known that Allium hookeri and one of its constituent compounds, rutin (RU), have anti-inflammatory, antioxidant, and antiplatelet effects.

OBJECTIVE

The aim of this study was to evaluate the regulation of AR by RU and A. hookeri.

METHODS

We assessed the therapeutic effects and the regulatory mechanisms of A. hookeri and RU on phorbol 12-myristate 13-acetate plus A23187 (PMACI) stimulated human mast cell line (HMC) 1 cells, and ovalbumin (OVA) sensitized mouse model of AR.

RESULTS

A. hookeri and RU significantly inhibited the production and messenger RNA (mRNA) expression of VEGF in PMACI-stimulated HMC-1 cells and significantly decreased VEGF levels in our murine AR model. The increased rubs scores and immunoglobulin E and interleukin (IL) 4 levels in OVA-sensitized mice were significantly reduced by the administration of A. hookeri, and RU significantly inhibited the production and mRNA expression and RU. Also, A. hookeri and RU significantly reduced IL-4 and IL-5 production in OVA-stimulated splenocytes. Furthermore, A. hookeri and RU significantly decreased chemokine levels (intercellular adhesion molecule-1, macrophage inflammatory protein-2) in nasal mucosa tissues. In the mouse AR model, A. hookeri and RU significantly prevented eosinophil and mast cell infiltration and reduced inflammatory cytokine levels induced by OVA sensitization. In addition, A. hookeri and RU significantly reduced mast cell-derived caspase-1 activity in OVA-sensitized mice.

CONCLUSION

The present study showed that A. hookeri or RU had an anti-allergic inflammatory effects. Analysis of these results indicated that A. hookeri and RU might protect against AR.

Augmentation of LPS-induced vascular endothelial cell growth factor production in macrophages by transforming growth factor-β1

The effect of LPS on the production of vascular endothelial growth factor (VEGF) was examined using RAW 264.7 macrophage cells. LPS induced VEGF production in RAW 264.7 cells and mouse peritoneal cells. LPS induced VEGF production via the expression of hypoxia inducible factor-1α and LPS-induced VEGF production was dependent on the activation of p38 MAPK and NF-κB activation· Transforming growth factor (TGF)-β1 augmented LPS-induced VEGF production, although TGF-β1 alone did not induce VEGF production. The augmentation of LPS-induced VEGF production by TGF-β1 was inhibited by a p38 MAPK inhibitor and was correlated with the phosphorylation of Smad3. The enhancing effect of TGF-β1 on LPS-induced VEGF production was observed in vivo in the skin lesions of mice receiving a subcutaneous injection of LPS. Taken together, it is suggested that LPS induced the VEGF production in macrophages and that it was augmented by TGF-β1 in vitro and in vivo.

Levels of Selected Aqueous Humor Mediators (IL-10, IL-17, CCL2, VEGF, FasL) in Diabetic Cataract

PURPOSE

To compare levels of selected mediators in serums and aqueous humor (AH) of type 2 diabetes mellitus cataract patients with senile cataract patients, and to determine their association with postoperative corneal edema (CE).

METHODS

Patients (32 senile and 29 diabetic cataract) undergoing standardized phacoemulsification combined with intraocular lens implantation were recruited. CE was assessed using an ordinal scale (grade 0 to 3). IL-10, CCL2, IL-17, FasL, and VEGF were measured by ELISA.

RESULTS

Diabetic patients had higher AH levels of VEGF (p = .042) and IL-10 (p = .021), lower AH levels of FasL (p = .048), and higher serum levels of CCL2 (p = .002). AH levels of CCL2 were higher in diabetic patients with more severe CE at the first postoperative day (p = .012).

CONCLUSIONS

We found disturbed AH microenvironment in diabetic cataract, with significant changes for VEGF, IL-10, and FasL. Higher CCL2 was associated with the development of early postoperative CE in diabetic patients.

Hydrocortisone reduces the beneficial effects of toll-like receptor 2 deficiency on survival in a mouse model of polymicrobial sepsis

INTRODUCTION

Toll-like receptors (TLRs) play a crucial role in early host defense against microorganisms. Toll-like receptor 2 (TLR2) polymorphisms have a prevalence of 10%; functional defects of TLR2 are associated with higher susceptibility toward gram-positive bacteria, and TLR2 deficiency has been associated with an impaired adrenal stress response. In the present study, we compared endogenous corticosterone production of wild-type (WT) and TLR2-deficient (TLR2) mice and analyzed survival after hydrocortisone therapy during sepsis induced by cecal ligation and puncture (CLP).

METHODS

Male C57BL/6J (WT); and B6.129-Tlr2tm1Kir/J (TLR2) mice were subjected to CLP or sham operation and randomly assigned to postoperative treatment with either hydrocortisone (5 mg/kg) or vehicle (n = 10 mice/group). Survival was documented for an observation period of 48 h. Endogenous corticosterone production following hydrocortisone treatment and lipoteichoic acid (LTA) exposure, interleukin 6 (IL-6) and IL-1β plasma levels, and blood counts were determined following sham operation or CLP using another n = 5 mice/group. Statistical analysis was performed using analysis of variance/Bonferroni.

RESULTS

TLR2 mice exhibited a lack of suppression and an attenuated increase in endogenous corticosterone production following hydrocortisone or LTA treatment, respectively. After CLP, TLR2 mice exhibited an uncompromised adrenal stress response, higher IL-6 levels, and increased survival compared with WT controls (75 vs. 35%; P < 0.05). Hydrocortisone therapy of TLR2 mice completely abolished this advantage (decrease in survival to 45%, P < 0.05 vs. vehicle-treated TLR2 mice) and was associated with decreased IL-1β plasma concentrations.

CONCLUSIONS

Toll-like receptor 2 deficiency is associated with an uncompromised adrenal stress response and increased survival rates during polymicrobial sepsis. Hydrocortisone treatment increases mortality of septic TLR2 mice, suggesting that hydrocortisone therapy might be harmful for individuals with functional TLR2 polymorphisms.

Decreased expression of serum and microvascular vascular endothelial growth factor receptor-2 in meningococcal sepsis*

OBJECTIVES

To determine the skin microvessel expression of vascular endothelial growth factor receptor 2 and serum-soluble vascular endothelial growth factor receptor 2 levels in children with meningococcal sepsis.

DESIGN

Observational study.

SETTING

Two tertiary academic children hospital PICUs.

PATIENTS

Children with meningococcal sepsis.

INTERVENTION

Skin biopsy and blood sample collection.

MEASUREMENTS AND MAIN RESULTS

Determination of skin microvessel vascular endothelial growth factor receptor 2 expression in skin biopsies by immunohistochemistry and measurement of serum-soluble vascular endothelial growth factor receptor 2 by enzyme-linked immunosorbent assay. Percentage of vascular endothelial growth factor receptor 2-positive skin microvessels and the staining intensity were significantly lower in children with meningococcal sepsis (n = 10) compared to controls (7.6% ± 8.8% vs 44.6% ± 39.2%; p = 0.009 and 0.7% ± 0.7% vs 1.7% ± 1.1%; p = 0.033, respectively). In addition, circulating serum levels of soluble vascular endothelial growth factor receptor 2 were decreased in sepsis (8,148 ± 1,140 pg/mL vs 13,414 ± 2,692 pg/mL; p < 0.001). Serum-soluble vascular endothelial growth factor receptor 2 levels (n = 28) were inversely correlated with Pediatric Risk of Mortality III score (r = -0.43; p = 0.023) and more decreased in nonsurvivors compared to survivors (5,640 ± 1,940 pg/mL vs 7,378 ± 2,336 pg/mL; p = 0.037).

CONCLUSIONS

Microvascular expression of vascular endothelial growth factor receptor 2 and serum-soluble vascular endothelial growth factor receptor 2 levels are decreased in children with sepsis. Serum-soluble vascular endothelial growth factor receptor 2 levels are inversely correlated with disease severity indicated by Pediatric Risk of Mortality III score and survival. Decreased vascular endothelial growth factor receptor 2 expression may hinder natural recovery from sepsis-associated microvascular injury and the effectiveness of therapeutic strategies targeting vascular endothelial growth factor-vascular endothelial growth factor receptor 2 signaling in sepsis patients.

Anti-vascular endothelial growth factor antibody attenuates inflammation and decreases mortality in an experimental model of severe sepsis

Introduction

Severe sepsis is associated with an unacceptably high rate of mortality. Recent studies revealed elevated levels of vascular endothelial growth factor (VEGF), a potent angiogenic and vascular permeability factor, in patients with sepsis. There was also an association between VEGF levels and sepsis severity. Here we investigate the effects of an anti-VEGF antibody (Bevacizumab, Bev) in an experimental model of sepsis.

Methods

Human umbilical vein endothelial cells (HUVECs), murine cecal ligation and puncture (CLP), and endotoxemia models of sepsis were used. HUVECs were treated with lipopolysaccharide (LPS) and/or Bev, harvested and cytokine mRNA levels determined using a semi-quantitative reverse transcription-polymerase chain reaction assay. The levels of inflammatory cytokine were also determined in HUVECs supernatants. In addition, the effects of Bev on mortality in the CLP and endotoxemia models of sepsis were evaluated.

Results

Treatment with Bev and LPS significantly decreased the expression and the level of inflammatory cytokines in HUVECs relative to LPS alone. In CLP and endotoxemia models, survival benefits were evident in mice given 0.1 mg/kg of Bev relative to the CLP or LPS alone (P <0.001 and P = 0.028, respectively), and in 6 h post-treated mice relative to the CLP alone for the effect of different time of Bev (P = 0.033). In addition, Bev treatment inhibited LPS-induced vascular leak in the lung, spleen and kidney in the murine endotoxemia model (P <0.05).

Conclusions

Anti-VEGF antibody may be a promising therapeutic agent due to its beneficial effects on the survival of sepsis by decreasing inflammatory responses and endothelial permeability.

Time-dependent alterations of VEGF and its signaling molecules in acute lung injury in a rat model of sepsis

Molecular mechanisms of sepsis-associated acute lung injury (ALI) are poorly defined. Since vascular endothelial growth factor (VEGF) is a potent vascular permeability and mitogenic factor, it might contribute to the development of ALI in sepsis. Thus, using lipopolysaccharide (LPS)-induced (15 mg/kg, intraperitoneal) endotoxemic rat model, we studied the timeline (1, 3, 6, and 10 h) of pulmonary VEGF expression and its signaling machinery. Levels of pulmonary VEGF and its angiogenic-mediating receptor, Flk-1, were downregulated by LPS in a time-dependent manner; levels of plasma VEGF and its permeability-mediating receptor, Flt-1, in contrast, was upregulated with time. In addition, blockade of Flt-1 could improve the downregulated pulmonary VEGF level and attenuate the elevated plasma and pulmonary levels of TNF-α, followed by improvement of arterial oxygenation and wet-to-dry weight ratio of the lung. Expression of signaling, pro- and or apoptotic factors after LPS administration were as follows: phosphorylated Akt, a downstream molecule was downregulated time dependently; endothelial nitric oxide synthase levels were significantly reduced; pro-apoptotic markers caspase 3 and Bax were upregulated whereas levels of Bcl-2 were downregulated. The present findings show that VEGF may play a role through the expression of Flt-1 in LPS-induced ALI. Moreover, downregulation of VEGF signaling cascade may account for LPS-induced apoptosis and impaired physiological angiogenesis in lung tissues, which in turn may contribute to the development of ALI induced by LPS.

Visual and optical coherence tomography outcomes of intravitreal bevacizumab and ranibizumab in inflammatory choroidal neovascularization secondary to punctate inner choroidopathy

PURPOSE

Choroidal neovascular membranes (CNV) are the major cause of visual loss in punctate inner choroidopathy (PIC), an idiopathic inflammatory condition predominantly affecting young, myopic women. We present a case series of 9 patients with CNV associated with PIC, treated with intravitreal anti-vascular endothelial growth factor agents.

METHODS

This is a retrospective case series of 9 patients treated with either intravitreal bevacizumab or ranibizumab for inflammatory CNV secondary to PIC. Initial and posttreatment converted logMAR visual acuity, fundus fluorescein angiograms (FFA), optical coherence tomography (OCT), previous and concurrent treatments, and side effects were recorded. Informed consent for treatment was obtained from each patient.

RESULTS

Nine patients (8 female, 1 male) with an average age of 34.4 years were treated for an average of 14.9 months. Six patients were treated with bevacizumab, and 3 with ranibizumab, with a mean of 2.34 injections per year. The mean visual acuity gain for the whole group of 9 patients was 0.26 converted logMAR units (Wilcoxon signed-rank test, p<0.015). Eight patients remained stable or had visual improvement at final follow-up, with a mean gain of 0.36 converted logMAR units. Only one patient's vision deteriorated (loss of 0.48 converted logMAR units). Concomitant short courses of oral corticosteroid were used in 3 of the 9 patients.

CONCLUSIONS

Over a 1-year period, bevacizumab and ranibizumab can be safely and successfully used to treat inflammatory CNV secondary to PIC, avoiding the need for systemic immunosuppression in the majority of patients.

Role of heparin on serum VEGF levels and local VEGF contents in reducing the severity of experimental severe acute pancreatitis in rats

OBJECTIVE

The aims of this study were to examine the effects of prophylactic heparin treatment during taurocholate-induced pancreatitis in rats and its impact on serum VEGF levels and local VEGF contents within the pancreas.

METHODS

Severe acute pancreatitis (SAP) was induced by injecting 4% sodium taurocholate into the pancreatic duct. Heparin at a dose of 150 IU/kg s.c. was administered 30 min before the operation. The rats were sacrificed 1 h, 3 h, 6 h and 12 h (n = 5 per time point) after the onset of pancreatitis. The severity of pancreatitis, serum VEGF levels and local VEGF contents were evaluated with and without heparin pretreatment.

RESULTS

The serum VEGF levels increased at an early phase of pancreatitis, and the highest level was found at 12 h after inducing pancreatitis. The gray value of the local VEGF showed a remarkable increase from the onset of the pancreatitis. However, the gray value of VEGF did not show an increase over time but maintained a high level during the entire process. Prophylactic heparin treatment significantly improved the morphologic changes, myeloperoxidase (MPO), TNF-α and malondialdehyde (MDA) activities. Meanwhile, it decreased the serum VEGF levels and the contents of VEGF within the pancreatic tissue.

CONCLUSIONS

The present study suggests that prophylactic heparin ameliorates the severity of taurocholate-induced pancreatitis via its anti-inflammatory properties. These protective effects may be partly due to decreasing serum VEGF levels and VEGF contents within the pancreas.

Histopathologic and immunohistochemical lesions in liver of mink infected with Aleutian disease virus

Parvovirus of Aleutian disease causes mainly damage to kidneys, but immune complexes deposition and damage may occur also in other organs. In mink farms of Latvia the liver dystrophy or hepatic lipidosis of mink is widely distributed. The goal of this study was to examine probability of liver damage and regeneration of mink infected with Aleutian disease virus. Liver injury was assessed histologically. The mink liver demonstrated inflammation of liver parenchyma and foci of fatty liver. In immunohistochemistry, during liver regeneration the matrix metalloproteinases MMP-9, vascular endothelial growth factor and beta-defensin 2 expressions were lower, but MMP-2 and nerve growth factor receptor p75 expression was increased.

The association between vascular endothelial growth factor levels and clinically evident peripheral edema in dogs with systemic inflammatory response syndrome

OBJECTIVE

To determine the relationship between plasma vascular endothelial growth factor (VEGF) levels, severity of illness, and edema formation in critically ill dogs.

DESIGN

Prospective, observational, descriptive, clinical study.

SETTING

University Teaching Hospital.

ANIMALS

Twenty-eight dogs.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Physical examination and multifrequency bioimpedance (MFBIA) measurements were performed daily on 28 critically ill dogs with evidence of severe inflammatory disease and compared with the corresponding plasma VEGF levels. The change in VEGF values and the relationship between MFBIA measurements and clinical evidence of edema were also examined. Eighteen dogs had a positive VEGF level, 12 dogs had clinical evidence of edema, and 7 dogs had both a positive VEGF level and clinical evidence of edema. There was no statistically significant correlation between VEGF levels and the presence of edema on physical examination (P=0.2). VEGF values were also evaluated with respect to WBC count, survival prediction index, presence of known sepsis, change in extracellular water, and outcome. No statistical relationship could be identified between VEGF levels in the blood of dogs with inflammatory disease and their survival prediction index (P=0.1), the WBC count (P=0.2), or presence of sepsis (P=0.2). Dogs with a VEGF level >70 pg/mL (n=3) were less likely to survive (P=0.04). Because of high variability within and between animals, conclusions regarding changes in MFBIA could not be made, suggesting that this technology requires further refinement and investigation in critically ill dogs.

CONCLUSIONS

A relationship between VEGF and clinically evident increased vascular permeability was not found in this study. Dogs with markedly elevated VEGF levels may be more likely to die, but further studies are needed to determine the diagnostic and prognostic value of VEGF in critically ill dogs.

Critical role of CD11b+ macrophages and VEGF in inflammatory lymphangiogenesis, antigen clearance, and inflammation resolution

Using a bacterial pathogen-induced acute inflammation model in the skin, we defined the roles of local lymphatic vessels and draining lymph nodes (DLNs) in antigen clearance and inflammation resolution. At the peak day of inflammation, robust expansion of lymphatic vessels and profound infiltration of CD11b+/Gr-1+ macrophages into the inflamed skin and DLN were observed. Moreover, lymph flow and inflammatory cell migration from the inflamed skin to DLNs were enhanced. Concomitantly, the expression of lymphangiogenic growth factors such as vascular endothelial growth factor C (VEGF-C), VEGF-D, and VEGF-A were significantly up-regulated in the inflamed skin, DLNs, and particularly in enriched CD11b+ macrophages from the DLNs. Depletion of macrophages, or blockade of VEGF-C/D or VEGF-A, largely attenuated these phenomena, and produced notably delayed antigen clearance and inflammation resolution. Conversely, keratin 14 (K14)-VEGF-C transgenic mice, which have dense and enlarged lymphatic vessels in the skin dermis, exhibited accelerated migration of inflammatory cells from the inflamed skin to the DLNs and faster antigen clearance and inflammation resolution. Taken together, these results indicate that VEGF-C, -D, and -A derived from the CD11b+/Gr-1+ macrophages and local inflamed tissues play a critical role in promoting antigen clearance and inflammation resolution.

Bevacizumab (avastin) and ranibizumab (lucentis) for choroidal neovascularization in multifocal choroiditis

BACKGROUND

Multifocal choroiditis (MFC) is an inflammatory condition, occasionally associated with choroidal neovascularization (CNV). Bevacizumab (Avastin) and ranibizumab (Lucentis) are therapies that target vascular endothelial growth factor. Bevacizumab and ranibizumab have been used successfully to treat CNV in age-related and myopic macular degeneration.

PURPOSE

: To describe the treatment of MFC-associated CNV with intravitreal bevacizumab and/or ranibizumab.

DESIGN

Retrospective interventional case series.

PARTICIPANTS

Six eyes of five patients with MFC-associated CNV were treated with intravitreal bevacizumab and/or ranibizumab.

MAIN OUTCOME MEASURES

Visual acuity at 1, 3, and 6 months after the initial injection.

RESULTS

Previous therapies (number of eyes treated) included sub-Tenon's corticosteroids (2), intravitreal corticosteroids (1), photodynamic therapy (1), and thermal laser (1). The mean number (range) of antivascular endothelial growth factor injections per eye was 2.3 (1-6). The mean duration (range) of follow-up per patient was 41.5 (25-69) weeks. Five of six eyes improved to 20/30 acuity or better at 6 months. One eye suffered a subfoveal rip of the retinal pigment epithelium with 20/400 acuity. There was a qualitative decrease in clinical and angiographic evidence of CNV.

CONCLUSIONS

Bevacizumab and ranibizumab were effective at improving visual acuity over 6 months in a small series of patients with MFC-associated CNV. Tears of the retinal pigment epithelium may occur after intravitreal antivascular endothelial growth factor therapy in MFC-associated CNV.

LPS-induced vascular endothelial growth factor expression in rat lung pericytes

Vascular endothelial growth factor (VEGF) is a potent angiogenic and vascular permeability factor. Recent studies have shown that the VEGF levels increase in several cell types, for example, macrophages and smooth muscle cells after LPS stimulation, suggesting that it is important in the initiation and development of sepsis. In particular, LPS-regulated contractility in lung pericytes may play an important role in mediating pulmonary microvascular fluid hemodynamics during sepsis. This study investigated the production of VEGF by rat lung pericytes in response to LPS. LPS was found to enhance VEGF mRNA expression in a concentration-dependent manner peaking 2 h after stimulation in pericytes. Vascular endothelial growth factor protein levels in conditioned medium and in cell lysate also increased on increasing LPS and peaked after 24 to 48 h. LPS also significantly augmented iNOS expression in lung pericytes within 6 h. However, iNOS mRNA induction occurred later than LPS-induced VEGF mRNA increases. Interestingly, attempted inhibition with nuclear factor-kappaB or tyrosine kinase did not suppress LPS-induced augmented VEGF mRNA expression in lung pericytes, although both inhibitors markedly inhibited LPS-induced iNOS mRNA expression. SB203580, a p38 MAP kinase inhibitor, repressed LPS-induced VEGF mRNA expression. Furthermore, LPS stimulated a rapid and sustained phosphorylation of p38 MAP kinase. These results show that pericytes produce VEGF in response to LPS stimulation, and that this may be partly mediated by the p38 MAP kinase pathway. More research should be done to establish the regulation of capillary hemodynamics and identify mechanisms of their regulation.

Novel PKC signaling is required for LPS-induced soluble Flt-1 expression in macrophages

In vitro activation of macrophages by LPS induces rapid release of vascular endothelial growth factor (VEGF) and soluble fms-like tyrosine kinase-1 receptor (sFlt-1), which are thought to be the effectors to cause sepsis. However, the signal pathway that controls the VEGF and sFlt-1 expressions in LPS-activated macrophages remains unclear. In this study, we demonstrated that phosphorylation of protein kinase C (PKC)delta played a key role in the VEGF and sFlt-1 signaling pathway of LPS-activated macrophages. PKC is a family of serine-threonine kinases, which are classified into three major groups based on homology and cofactor requirements: conventional PKCs, novel PKCs, and atypical PKCs. In the murine RAW264.7 cells, as well as in primary human monocytes/macrophages, pretreatment with a general PKC inhibitor GF109203X or with a novel PKCdelta inhibitor rottlerin or overexpression of a kinase-inactive form of PKCdelta (K376R) eliminated LPS-induced sFlt-1 expression and augmented LPS-induced VEGF expression at the protein and the transcription levels. In contrast, Gö6976, an inhibitor for the conventional PKCs, or myristoylated PKCzeta pseudosubstrate peptide, an inhibitor for the atypical PKCs, failed to exert the same effects. These data suggest that PKCdelta signaling is involved in LPS-induced sFlt-1 expression and serves as a negative mediator in LPS-induced VEGF expression in macrophages. A novel strategy controlling the LPS-induced PKC pathways, especially the PKCdelta isoform, may be developed based on this study.

Admission angiopoietin levels in children with septic shock

Angiopoietin (angpt) 1 and angpt-2 are circulating proteins first ascribed opposing roles in embryonic angiogenesis. Both bind the tyrosine kinase with immunoglobulin-like loop and epidermal growth factor homology domains (Tie) 2 receptor on endothelial cells, but angpt-1 is a Tie-2 agonist, whereas angpt-2 antagonizes Tie-2 signaling. In the developed vasculature, angpt-1 protects against vascular leak, whereas angpt-2 promotes increased vascular permeability. Because alterations in vascular permeability are common in septic shock, we obtained plasma from critically ill children within 24 h of diagnosis of the systemic inflammatory response syndrome (SIRS, n = 20), sepsis (n = 20), or septic shock (n = 61), as well as 15 healthy controls. Plasma levels of angpt-1 and angpt-2 were measured via a commercially available enzyme-linked immunosorbent assay. Plasma angpt-2 levels were significantly elevated in children with septic shock when compared with healthy children, as well as critically ill children with either SIRS or sepsis, and circulating angpt-2 levels seemed to correlate with disease severity and outcome. In addition, plasma angpt-1 levels were significantly decreased in critically ill children with septic shock compared with critically ill children with either SIRS or sepsis. Given the contrasting effects of angpt-2 and angpt-1 on the vascular endothelium, these two factors may play an important role in the pathophysiology of septic shock in children, and further studies are warranted.

Excess circulating angiopoietin-2 may contribute to pulmonary vascular leak in sepsis in humans

BACKGROUND

Acute respiratory distress syndrome (ARDS) is a devastating complication of numerous underlying conditions, most notably sepsis. Although pathologic vascular leak has been implicated in the pathogenesis of ARDS and sepsis-associated lung injury, the mechanisms promoting leak are incompletely understood. Angiopoietin-2 (Ang-2), a known antagonist of the endothelial Tie-2 receptor, was originally described as a naturally occurring disruptor of normal embryonic vascular development otherwise mediated by the Tie-2 agonist angiopoietin-1 (Ang-1). We hypothesized that Ang-2 contributes to endothelial barrier disruption in sepsis-associated lung injury, a condition involving the mature vasculature.

METHODS AND FINDINGS

We describe complementary human, murine, and in vitro investigations that implicate Ang-2 as a mediator of this process. We show that circulating Ang-2 is significantly elevated in humans with sepsis who have impaired oxygenation. We then show that serum from these patients disrupts endothelial architecture. This effect of sepsis serum from humans correlates with measured Ang-2, abates with clinical improvement, and is reversed by Ang-1. Next, we found that endothelial barrier disruption can be provoked by Ang-2 alone. This signal is transduced through myosin light chain phosphorylation. Last, we show that excess systemic Ang-2 provokes pulmonary leak and congestion in otherwise healthy adult mice.

CONCLUSIONS

Our results identify a critical role for Ang-2 in disrupting normal pulmonary endothelial function.