Expression and release of angiopoietin-1 from human neutrophils: intracellular mechanisms

Loss of soluble guanylyl cyclase in platelets contributes to atherosclerotic plaque formation and vascular inflammation

Variants in genes encoding the soluble guanylyl cyclase (sGC) in platelets are associated with coronary artery disease (CAD) risk. Here, by using histology, flow cytometry and intravital microscopy, we show that functional loss of sGC in platelets of atherosclerosis-prone Ldlr^-/- mice contributes to atherosclerotic plaque formation, particularly via increasing in vivo leukocyte adhesion to atherosclerotic lesions. In vitro experiments revealed that supernatant from activated platelets lacking sGC promotes leukocyte adhesion to endothelial cells (ECs) by activating ECs. Profiling of platelet-released cytokines indicated that reduced platelet angiopoietin-1 release by sGC-depleted platelets, which was validated in isolated human platelets from carriers of GUCY1A1 risk alleles, enhances leukocyte adhesion to ECs. I mp or ta ntly, p ha rm ac ol ogical sGC stimulation increased platelet angiopoietin-1 release in vitro and reduced leukocyte recruitment and atherosclerotic plaque formation in atherosclerosis-prone Ldlr^-/- mice. Therefore, pharmacological sGC stimulation might represent a potential therapeutic strategy to prevent and treat CAD.

Neutrophil Extracellular Traps, Angiogenesis and Cancer

Human neutrophils, the most abundant circulating leukocytes, are fundamental components of the host response against different pathogens. Until a few years ago, neutrophils received limited attention in cancer immunology. Recently, it was discovered that both circulating, and tumor-associated, neutrophils possess functional plasticity when exposed to various inflammatory stimuli and in the tumor microenvironment. Neutrophils and their mediators can exert several pro-tumor activities in cancer and promote metastasis through different mechanisms. Angiogenesis plays a pivotal role in inflammation and tumor growth. Activated human neutrophils release several angiogenic factors [vascular endothelial growth factor-A (VEGF-A), angiopoietin-1 (ANGPT1), CXCL8, hepatocyte growth factor (HGF), and metalloproteinase 9 (MMP-9)] and form neutrophil extracellular traps (NETs). NETs promote tumor growth and metastasis formation through several mechanisms: they can awake dormant cancer cells, capture circulating tumor cells, coat and shield cancer cells, thus preventing CD8⁺- and natural killer (NK) cell-mediated cytotoxicity. ANGPTs released by endothelial and periendothelial mural cells induce platelet-activating factor (PAF) synthesis and neutrophil adhesion to endothelial cells. NETs can directly exert several proangiogenic activities in human endothelial cells and NETs induced by ANGPTs and PAF increase several aspects of angiogenesis in vitro and in vivo. A better understanding of the pathophysiological functions of NETs in cancer and angiogenesis could be of importance in the early diagnosis, prevention and treatment of tumors.

Effects of immune cells on mesenchymal stem cells during fracture healing

In vertebrates, bone is considered an osteoimmune system which encompasses functions of a locomotive organ, a mineral reservoir, a hormonal organ, a stem cell pool and a cradle for immune cells. This osteoimmune system is based on cooperatively acting bone and immune cells, cohabitating within the bone marrow. They are highly interdependent, a fact that is confounded by shared progenitors, mediators, and signaling pathways. Successful fracture healing requires the participation of all the precursors, immune and bone cells found in the osteoimmune system. Recent evidence demonstrated that changes of the immune cell composition and function may negatively influence bone healing. In this review, first the interplay between different immune cell types and osteoprogenitor cells will be elaborated more closely. The separate paragraphs focus on the specific cell types, starting with the cells of the innate immune response followed by cells of the adaptive immune response, and the complement system as mediator between them. Finally, a brief overview on the challenges of preclinical testing of immune-based therapeutic strategies to support fracture healing will be given.

Angiopoietin 1 release from human neutrophils is independent from neutrophil extracellular traps (NETs)

Background

Neutrophils induce the synthesis and release of angiopoietin 1 (Ang1), a cytosolic growth factor involved in angiogenesis and capable of inducing several pro-inflammatory activities in neutrophils. Neutrophils also synthesize and release neutrophil extracellular traps (NETs), comprised from decondensed nuclear DNA filaments carrying proteins such as neutrophil elastase (NE), myeloperoxidase (MPO), proteinase 3 (PR3) and calprotectin (S100A8/S100A9), which together, contribute to the innate immune response against pathogens (e.g., bacteria). NETs are involved in various pathological conditions through pro-inflammatory, pro-thrombotic and endothelial dysfunction effects and have recently been found in heart failure (HF) and type 2 diabetes (T2DM) patients. The aim of the present study was to investigate the role of NETs on the synthesis and release of Ang1 by the neutrophils in patients with T2DM and HF with preserved ejection fraction (HFpEF) (stable or acute decompensated; ADHFpEF) with or without T2DM.

Results

Our data show that at basal level (PBS) and upon treatment with LPS, levels of NETs are slightly increased in patients suffering from T2DM, HFpEF ± T2DM and ADHF without (w/o) T2DM, whereas this increase was significant in ADHFpEF + T2DM patients compared to healthy control (HC) volunteers and ADHFpEF w/o T2DM. We also observed that treatments with PMA or A23187 increase the synthesis of Ang1 (from 150 to 250%) in HC and this effect is amplified in T2DM and in all cohorts of HF patients. Ang1 is completely released (100%) by neutrophils of all groups and does not bind to NETs as opposed to calprotectin.

Conclusions

Our study suggests that severely ill patients with HFpEF and diabetes synthesize and release a greater abundance of NETs while Ang1 exocytosis is independent of NETs synthesis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12865-021-00442-8.

The Prognostic Significance of Combined Pretreatment Fibrinogen and Neutrophil-Lymphocyte Ratio in Various Cancers: A Systematic Review and Meta-Analysis

Purpose

The prognostic value of a new scoring system, termed F-NLR, that combines pretreatment fibrinogen level with neutrophil-lymphocyte ratio has been evaluated in various cancers. However, the results are controversial. The purpose of this study was to comprehensively analyze the prognostic value of F-NLR score in patients with cancers.

Methods

An integrated search of relevant studies was conducted by screening the PubMed and Embase databases. Pooled hazard ratios, with 95% confidence intervals (CIs), for overall survival (OS) and disease-free survival (DFS)/progression-free survival (PFS) were calculated to estimate the prognostic significance of F-NLR score in patients with various tumors. A random effects model was used for comprehensive analysis, and subgroup and meta-regression analyses were used to explore sources of heterogeneity.

Results

Thirteen articles reporting data from of 4747 patients were included in the study. Pooled analysis revealed that high F-NLR score was significantly associated with poor OS (HR = 1.77; 95% CI, 1.51–2.08) and poor DFS/PFS (HR = 1.63; 95% CI, 1.30–2.05). Subgroup and meta-regression analyses did not alter the prognostic role of F-NLR score in OS and DFS/PFS.

Conclusions

Increased F-NLR score is significantly associated with poor prognosis in patients with cancers and can serve as an effective prognostic indicator.

Regorafenib treatment outcome for Taiwanese patients with metastatic gastrointestinal stromal tumors after failure of imatinib and sunitinib: A prospective, non-randomized, single-center study

The present study aimed to conduct a prognosis analysis of Taiwanese patients with metastatic gastrointestinal stromal tumors (GISTs), who are resistant to or were unable to tolerate imatinib or sunitinib, and were subsequently treated with regorafenib. The study considered the survival, potential prognostic factors and safety of these Taiwanese patients. A total of 28 patients with pre-treated metastatic GIST, receiving regorafenib treatment, were analyzed between April 2014 and December 2017. Data were collected prospectively, and patients were followed up for a median of 14.8 months. It was reported that 50% (10/20) of male patients and 50% (4/8) of female patients demonstrated response and clinical benefit to regorafenib. The median progression-free survival (PFS) and overall survival (OS) time in all patients receiving regorafenib were 4.4 and 29.3 months, respectively. Good performance status and disease control mediated by regorafenib were independently associated with a more favorable PFS time. Good performance status, higher pre-treated albumin level, lower neutrophil:lymphocyte ratio (NLR) and lower platelet:lymphocyte ratio (PLR) were independent favorable predictors of OS time. Overall, poor performance status and poor disease control predicted a less favorable PFS time in Taiwanese patients with GISTs, who were pre-treated with regorafenib. Meanwhile poor performance status, high NLR, PLR and low albumin level predicted a less favorable OS time.

Two-Faced Roles of Tumor-Associated Neutrophils in Cancer Development and Progression

Neutrophils are the most abundant circulating leukocytes in humans. Neutrophil infiltration into tumor tissues has long been observed but its roles have been ignored due to the presumed short life cycle and metabolic incompetence of neutrophils. Recent advances in neutrophil biology research have revealed that neutrophils have a longer life cycle with a potential to express various bioactive molecules. Clinical studies have simultaneously unraveled an increase in the neutrophil–lymphocyte ratio (NLR), a ratio of absolute neutrophil to absolute lymphocyte numbers in cancer patient peripheral blood and an association of higher NLR with more advanced or aggressive disease. As a consequence, tumor-associated neutrophils (TANs) have emerged as important players in tumor microenvironment. The elucidation of the roles of TANs, however, has been hampered by their multitude of plasticity in terms of phenotypes and functionality. Difficulties are further enhanced by the presence of a related cell population—polymorphonuclear leukocyte (PMN)-myeloid-derived suppressor cells (MDSCs)—and various dissimilar aspects of neutrophil biology between humans and mice. Here, we discuss TAN biology in various tumorigenesis processes, and particularly focus on the context-dependent functional heterogeneity of TANs.

Circulating Leukocyte Alterations and the Development/Progression of Diabetic Retinopathy in Type 1 Diabetic Patients - A Pilot Study

BACKGROUND/AIMS

The aim of this study was to investigate the relationship between alterations in circulating leukocytes and the initiation and progression of DR in people with type 1 diabetes (T1D).

METHODS

Forty-one patients with T1D [13 mild non-proliferative DR (mNPDR), 14 active proliferative DR (aPDR) and 14 inactive PDR (iPDR)], and 13 age- and gender-matched healthy controls were recruited prospectively. Circulating leukocytes, including CD4⁺ and CD8⁺ T-cells, CD14⁺CD16^-, CD14^-CD16⁺ and CD14⁺CD16⁺ monocytes; CD16⁺HLA-DR^- neutrophils, CD19⁺ B-cells and CD56⁺ natural killer cells and their cell surface adhesion molecules and chemokine receptors (HLA-DR, CD62L, CCR2, CCR5, CD66a, CD157 and CD305) were examined by flow cytometry.

RESULTS

In DR patients, compared to healthy controls, increased proportions of neutrophils (p = .0152); reduced proportions of lymphocytes (p = .0002), HLA-DR⁺ leukocytes (p = .0406) and non-classical monocytes (p = .0204); and reduced expression of CD66a (p = .0048) and CD157 (p = .0007) on CD4⁺ T cells were observed. Compared to healthy controls, CD19⁺ B cells were reduced at the mNPDR but not aPDR patients. Total lymphocytes, CD4⁺ T cells and CD8⁺ T cells progressively decreased whereas neutrophils, the neutrophil/lymphocyte ratio and the neutrophil/CD4⁺ ratio progressively increased from early to late stages of DR, reaching statistical significance at the aPDR stage. Longer diabetes duration was associated with a reduced proportion of CD8⁺ T cells (p = .002) and increased neutrophil/CD8⁺ ratio (p = .033).

CONCLUSIONS

In this pilot study, DR is associated with increased innate cellular immunity especially neutrophils and reduced adaptive cellular immunity particularly lymphocytes. Impaired B-cell immunity may play a role in the initiation of DR; whereas impaired T-cell immunity with increased neutrophil response may contribute to progression of DR from non-proliferative to proliferative stages in T1D patients. Large multicenter studies are needed to further understand the immune dysregulation in DR initiation and progression.

Neutrophil-To-Lymphocyte Ratio Predicted Long-Term Chemotherapy Benefits In Stage IIIB-IV Non-Squamous Non-Small Cell Lung Cancer Patients Without Sensitive Mutations

Purpose

To investigate the predictive capability of clinical parameters for long-term chemotherapy benefits among stage IIIB-IV non-squamous non-small cell lung cancer (NSCLC) patients without sensitive mutations.

Patients and methods

We investigated the clinical features of 206 stage IIIB-IV non-squamous NSCLC patients without sensitive mutations and assessed their predictive value for disease control rate (DCR) at 6 and 12 months post-treatment.

Results

Seventy-two patients received docetaxel and platinum-based chemotherapy while 134 received pemetrexed and platinum-based chemotherapy. The 6-month and 12-month DCR were 33 (45.8%) and 6 (8.3%) in the docetaxel group and 69 (51.5%) and 19 (14.2%) in the pemetrexed group, respectively. Univariate Cox regression revealed that age, sex, smoking history, adrenal gland metastasis, stage IV disease, neutrophil-to-lymphocyte ratio (NLR), and serum albumin were associated with unfavorable progression-free survival (PFS). Age, stage IV disease, and NLR were identified as independent predictors of PFS using multivariate analysis. NLR was the only parameter that could predict 3-month and 6-month DCRs. NLR and age were able to predict 12-month DCR, with NLR presenting a larger area under the curve. Kaplan–Meier curves demonstrated that patients with NLR > 2.231 displayed significantly reduced long-term disease control. The group with higher NLR had more male patients, lower ALB levels, and serum sodium levels as well as higher platelet counts.

Conclusion

NLR was an independent predictor of long-term chemotherapy benefits among non-squamous NSCLC patients without sensitive mutations. Patients with lower NLR were optimal candidates for chemotherapy. Patients with high NLR may receive alternative treatments or be included in clinical trials.

Effects of inflammatory cytokines on bone/cartilage repair

Many inflammatory factors can affect cell behaviors and work as a form of inter-regulatory networks through the inflammatory pathway. Inflammatory cytokines are critical for triggering bone regeneration after fracture or bone injury. Also, inflammatory cytokines play an important role in cartilage repair. The synergistic or antagonistic effects of both proinflammatory and anti-inflammatory cytokines have a great influence on fracture healing. This review discusses key inflammatory cytokines and signaling pathways involved in bone or cartilage repair.

Prognostic significance of the combination of preoperative fibrinogen and the neutrophil-lymphocyte ratio in patients with non-small cell lung cancer following surgical resection

The purpose of the present study was to evaluate the prognostic value of preoperative coagulation factor levels (including fibrinogen and D-dimer) and inflammatory indicators in patients with non-small cell lung cancer (NSCLC). The medical records of 456 patients with NSCLC who had undergone curative resection were retrospectively analysed. The recommended cut-off values for preoperative fibrinogen, neutrophil-lymphocyte ratio (NLR), platelet-lymphocyte ratio and lymphocyte-monocyte ratio were determined using receiver operating characteristic curve analyses. The associations between preoperative fibrinogen or D-dimer levels and clinicopathological variables were analysed using the χ² test. Univariate Kaplan-Meier analysis and a multivariate Cox proportional hazards model were applied to identify which prognostic variables were significantly associated with overall survival (OS) rates. Multivariate analyses revealed that lymph node metastasis (P<0.001), preoperative fibrinogen (P=0.024) and NLR (P=0.028) were effective independent prognostic variables associated with OS. Based on this result, a novel, single inflammation-based combination of fibrinogen and NLR (COF-NLR) score was proposed for the determination of prognosis. Patients with elevated fibrinogen and NLR levels were allocated a score of 2 (n=136), and those that demonstrated elevated levels of one or neither were allocated a score of 1 (n=152) or 0 (n=168), respectively. The 5-year OS rates were significantly poorer for patients with COF-NLR=2 compared with those with COF-NLR=1 or 0 (23.5% vs. 34.2% vs. 50.0%, P<0.001). A subgroup analysis demonstrated that the prognostic significance of COF-NLR was independent of histological subtype, lymph node metastasis and pathological stage. Therefore, COF-NLR has potential as a novel and useful blood marker for predicting tumour progression and the postoperative survival of patients with NSCLC. It may assist clinicians in risk stratification, prognosis predictions and facilitating individualised treatment.

Neutrophil count is associated with myeloid derived suppressor cell level and presents prognostic value of for hepatocellular carcinoma patients

Myeloid Derived Suppressor Cell (MDSC) has been raised to be a novel target for multiple cancers. However, target agents on MDSC have not display promising efficacy. One of the critical reasons shall be less optimal patient selection. In the present study, we aimed to identify clinical parameters relevant to MDSC level in hepatocellular carcinoma (HCC) patients for future MDSC targeted therapy. In the present study, a series of 55 HCC patients (testing group) and 20 healthy donors were analyzed investigating frequencies of MDSC in peripheral blood mononuclear cells (PBMC). As a result, we found that MDSC level was increased in HCC patients compared to healthy donors (10.33% vs 1.54%, p < 0.0001). The monocytes (r² = 0.2875, p < 0.0001), neutrophils (r² = 0.3630, p < 0.0001) and platelet counts (r² = 0.0828, p = 0.0331) in circulation was positively associated with MDSC level. Then, the prognostic value of the above predictors was determined in a retrospective database of 255 HCC patients (validation group). The baseline characteristics of testing and validation group were similar. Multivariate analysis by Cox regression revealed that neutrophil count was an independent predictor for overall survival (OS) (p = 0.000, HR 1.065, 95% CI 1.028–1.103), with the rest parameters failed to reach a significant result. In summary, the present study firstly identified blood neutrophil counts was a predictor of MDSC level in PBMC for HCC patients. And, patients with higher neutrophil count level might be the optimal patient subgroup for MDSC targeted therapy.

Pretreatment blood neutrophil/lymphocyte ratio is associated with metastasis and predicts survival in patients with pancreatic cancer

BACKGROUND

The predictive value of systemic inflammatory markers has been explored in various types of cancer. In the present study, we aimed to investigate the association between pretreatment neutrophil/lymphocyte ratio (NLR) and tumor metastasis in pancreatic cancer, and the values of NLR as a prognostic factor of overall survival.

METHODS

Clinical and laboratory data from 256 consecutive pancreatic cancer patients were analyzed retrospectively. The NLR was recorded before treatment and analyzed along with clinicopathological characteristics and overall survival of pancreatic cancer patients.

RESULTS

Multivariate analysis revealed that pretreatment NLR (HR: 2.393; 95% CI: 1.326-4.320; P=0.004) was an independent risk factor for distant metastasis. Furthermore, COX regression analysis showed that in addition to pretreatment NLR (HR: 1.871; 95% CI: 1.413-2.477; P<0.001), metastasis and stage were independent prognostic factors.

CONCLUSION

Pretreatment NLR values were significantly associated with distant metastasis in pancreatic cancer patients. Higher NLR values were detected in metastatic disease and may be an independent prognostic factor of overall survival in pancreatic cancer patients.

Inflammatory Markers as Prognostic Factors of Survival in Patients Affected by Hepatocellular Carcinoma Undergoing Transarterial Chemoembolization

Introduction

Transarterial chemoembolization (TACE) is a good choice for hepatocellular carcinoma (HCC) treatment when surgery and liver transplantation are not feasible. Few studies reported the value of prognostic factors influencing survival after chemoembolization. In this study, we evaluated whether preoperative inflammatory factors such as neutrophil to lymphocyte ratio and platelet to lymphocyte ratio affected our patient survival when affected by hepatocellular carcinoma.

Methods

We retrospectively evaluated a total of 72 patients with hepatocellular carcinoma that underwent TACE. We enrolled patients with different etiopathogeneses of hepatitis and histologically proven HCC not suitable for surgery. The overall study population was dichotomized in two groups according to the median NLR value and was analyzed also according to other prognostic factors.

Results

The global median overall survival (OS) was 28 months. The OS in patients with high NLR was statistically significantly shorter than that in patients with low NLR. The following pretreatment variables were significantly associated with the OS in univariate analyses: age, Child-Pugh score, BCLC stage, INR, and NLR. Pretreated high NLR was an independently unfavorable factor for OS.

Conclusion

NLR could be considered a good prognostic factor of survival useful to stratify patients that could benefit from TACE treatment.

The Sabotaging Role of Myeloid Cells in Anti-Angiogenic Therapy: Coordination of Angiogenesis and Immune Suppression by Hypoxia

Tumor angiogenesis has become a promising target for anti-tumor therapy. Unfortunately, the somewhat inevitable occurrence of resistance has limited the efficacy of anti-angiogenic therapy. In addition to their well-established role in immune suppression, bone marrow-derived myeloid cells actively contribute to tumor angiogenesis. More importantly, myeloid cells constitute one of the major mechanisms of resistance to angiogenesis inhibition. As the most pervasive feature in tumor microenvironment, hypoxia is able to initiate both pro-angiogenic and immunosuppressive capacities of myeloid cells. Tumor adapts to hypoxic stress primarily through signaling mediated by hypoxic inducible factors (HIFs) and consequently utilizes hypoxia to its own advantage. In this regard, hypoxia orchestrates both angiogenesis and immune evasion to support tumor growth. In this article, we will review available information on the sabotaging role of myeloid cells in anti-angiogenic therapy. We will also discuss how hypoxia coordinates the dual-role cellular and molecular participants in microenvironment to maximize the efficiency of angiogenesis and immunosuppression to promote tumor progression. J. Cell. Physiol. 232: 2312-2322, 2017. © 2016 Wiley Periodicals, Inc.

Prognostic Significance of Neutrophil to Lymphocyte Ratio, Lymphocyte to Monocyte Ratio, and Platelet to Lymphocyte Ratio in Patients with Nasopharyngeal Carcinoma

The peripheral blood neutrophil to lymphocyte ratio (NLR), lymphocyte to monocyte ratio (LMR), and platelet to lymphocyte ratio (PLR) have been reported to correlate with the prognosis of many malignancies. This study evaluated the prognostic value of pretreatment NLR, LMR, and PLR in nasopharyngeal carcinoma (NPC). A retrospective analysis of clinical and pathological data of 140 NPC patients without distant metastasis during initial treatment was conducted to identify correlations between NLR, LMR, and PLR and clinicopathological features, overall survival, and progression-free survival. Cox proportional hazard regression analysis was used to reveal the independent factors affecting the prognosis of NPC patients. NLR was associated with T staging, N staging, and overall clinical stage grouping of the NPC patients (P < 0.05). NLR ≥ 2.28, LMR < 2.26, and PLR ≥ 174 were significantly associated with a relatively short overall survival (P < 0.05). In addition, NLR ≥ 2.28 was significantly associated with a relatively short progression-free survival (P < 0.05). Cox proportional hazard regression analysis showed that NLR was an independent prognostic factor in NPC. Pretreatment NLR, LMR, and PLR might be a useful complement to TNM staging in the prognostic assessment of NPC patients.

Incorporation of NLR into NIH stratification system increases predictive accuracy for surgically resected gastrointestinal stromal tumors

Previous studies have reported that preoperative neutrophil-to-lymphocyte (NLR) and platelet-to-lymphocyte ratios were prognostic for various types of cancers. The aim of this study was to investigate the predictive utilities of preoperative peripheral blood counts in patients with gastrointestinal stromal tumors (GISTs). We enrolled 510 consecutive, previously untreated patients who underwent surgery for primary, localized GISTs. The relationship between recurrence-free survival and outcome variables was assessed by univariate and multivariate analyses, while the clinicopathologic relevance of NLR was determined using the Chi-square test. A preoperative NLR ≥2 was associated with poor prognosis in patients undergoing surgeries for primary, localized GISTs. It was an independent predictor only in patients classified as National Institutes of Health high risk but not in the entire population. Preoperative NLR is a feasible and reproducible peripheral biomarker that helps identify patients for intensive adjuvant therapy and frequent surveillance.

Group V Secreted Phospholipase A2 Induces the Release of Proangiogenic and Antiangiogenic Factors by Human Neutrophils

Secreted phospholipases A₂ (sPLA₂s) are extracellular enzymes that catalyze the release of free fatty acids and lysophospholipids from membrane phospholipids and also bind to different receptors (e.g., PLA₂R1 or integrins). To date, 12 mammalian sPLA₂s have been identified, which play a critical role in pathophysiological processes including inflammation and cancer. sPLA₂s activate immune cells such as human neutrophils (PMNs) by enzymatic activity- or receptor-mediated mechanisms. In addition, human PMNs synthesize and store human group V (hGV) and human group X (hGX) sPLA₂s in their granules, but only the former is released upon cellular activation. We investigated the effects of sPLA₂s on the release of proangiogenic and antiangiogenic factors by PMNs. We found that exogenous hGV and hGX sPLA₂s induce the release of vascular endothelial growth factor (VEGF)-A, angiopoietin 1 (Ang1), and CXCL8/IL-8. Only hGV induces the secretion of the antiangiogenic isoform of VEGF-A, namely, VEGF-A_165b. While the release of VEGF-A, Ang1, and CXCL8/IL-8 was likely mediated by hGV enzymatic activity and/or binding to PLA₂R1 and heparan sulfate proteoglycans, the release of VEGF-A_165b requires the interaction with α_Vβ₃ and α₄β₁ integrins. We also provide evidence that endogenous hGV released by N-formyl-met-leu-phe (fMLF)-activated PMNs is involved in the release of angiogenic factors. The translational relevance of these data is supported by our findings that hGV expression is increased in human samples of lung cancer which are infiltrated by PMNs. Overall, our results suggest that the hGV-neutrophil axis may play a relevant role in the modulation of cancer-related inflammation and angiogenesis.

Dynamic change of the systemic immune inflammation index predicts the prognosis of patients with hepatocellular carcinoma after curative resection

BACKGROUND

The aim of the study was to determine the utility of the dynamic change and serial monitoring of the systemic immune inflammation index (SII), which was based on the numbers of patients' lymphocytes (L), platelets (P), neutrophils (N) and defined as P*N/L, for predicting prognosis of patients with hepatocellular carcinoma (HCC) after curative resection.

METHODS

We conducted a prospective study of 163 patients with HCC who underwent curative resection at Zhongshan Hospital from January 2012 to May 2013. SII was calculated using data acquired before and approximately 1 month after surgery. An optimal cutoff value stratified patients into groups with high or low SII. Patients were classified into unfavorable and favorable groups using the dynamic change of the SII. Two groups that were further divided into four categories within the entire cohort and the low-risk subgroups were serially monitored for ≥6 months. Prognostic values of the SII and other factors were determined using the Kaplan-Meier method, the Cox proportional hazards model, and the receiver operating characteristics (ROC) curve.

RESULTS

The favorable group was likely to have cirrhosis, and the unfavorable group was likely to have larger tumors and a higher recurrence rate. Multivariate analysis revealed that tumor size and dynamic change of the SII were independent risk factors for early recurrence. Moreover, the predictive value of the SII was retained in α-fetoprotein (AFP)-negative and HBeAg-negative-HBV-DNA <2000 IU/mL subgroups. Further, the serial changes of the SII for recurrence and no recurrence groups were statistically significant.

CONCLUSIONS

The dynamic change and serial monitoring of the SII represent new indicators for predicting the early recurrence of HCC determining advance optimal therapy in advance.

New Insights into the Pro-Inflammatory Activities of Ang1 on Neutrophils: Induction of MIP-1β Synthesis and Release

We reported the expression of angiopoietin Tie2 receptor on human neutrophils and the capacity of angiopoietins (Ang1 and Ang2) to induce pro-inflammatory activities, such as platelet-activating factor synthesis, β₂-integrin activation and neutrophil migration. Recently, we observed differential effects between both angiopoietins, namely, the capacity of Ang1, but not Ang2, to promote rapid interleukin-8 synthesis and release, as well as neutrophil viability. Herein, we addressed whether Ang1 and/or Ang2 could modulate the synthesis and release of macrophage inflammatory protein-1β (MIP-1β) by neutrophils. Neutrophils were isolated from blood of healthy volunteers; intracellular and extracellular MIP-1β protein concentrations were assessed by ELISA. After 24 hours, the basal intracellular and extracellular MIP-1β protein concentrations were ≈500 and 100 pg/10⁶ neutrophils, respectively. Treatment with Ang1 (10 nM) increased neutrophil intracellular and extracellular MIP-1β concentrations by 310 and 388% respectively. Pretreatment with PI3K (LY294002), p38 MAPK (SB203580) and MEK (U0126) inhibitors completely inhibited Ang1-mediated increase of MIP-1β intracellular and extracellular protein levels. Pretreatment with NF-κB complex inhibitors, namely Bay11-7085 and IKK inhibitor VII or with a transcription inhibitor (actinomycin D) and protein synthesis inhibitor (cycloheximide), did also abrogate Ang1-mediated increase of MIP-1β intracellular and extracellular protein levels. We validated by RT-qPCR analyses the effect of Ang1 on the induction of MIP-1β mRNA levels. Our study is the first one to report Ang1 capacity to induce MIP-1β gene expression, protein synthesis and release from neutrophils, and that these effects are mediated by PI3K, p38 MAPK and MEK activation and downstream NF-κB activation.

VEGF and angiopoietins promote inflammatory cell recruitment and mature blood vessel formation in murine sponge/Matrigel model

A key feature in the induction of pathological angiogenesis is that inflammation precedes and accompanies the formation of neovessels as evidenced by increased vascular permeability and the recruitment of inflammatory cells. Previously, we and other groups have shown that selected growth factors, namely vascular endothelial growth factor (VEGF) and angiopoietins (Ang1 and Ang2) do not only promote angiogenesis, but can also induce inflammatory response. Herein, given a pro-inflammatory environment, we addressed the individual capacity of VEGF and angiopoietins to promote the formation of mature neovessels and to identify the different types of inflammatory cells accompanying the angiogenic process over time. Sterilized polyvinyl alcohol (PVA) sponges soaked in growth factor-depleted Matrigel mixed with PBS, VEGF, Ang1, or Ang2 (200 ng/200 µl) were subcutaneously inserted into anesthetized mice. Sponges were removed at day 4, 7, 14, or 21 post-procedure for histological, immunohistological (IHC), and flow cytometry analyses. As compared to PBS-treated sponges, the three growth factors promoted the recruitment of inflammatory cells, mainly neutrophils and macrophages, and to a lesser extent, T- and B-cells. In addition, they were more potent and more rapid in the recruitment of endothelial cells (ECs) and in the formation and maturation (ensheating of smooth muscle cells around ECs) of neovessels. Thus, the autocrine/paracrine interaction among the different inflammatory cells in combination with VEGF, Ang1, or Ang2 provides a suitable microenvironment for the formation and maturation of blood vessels.

Pretreatment hematologic markers as prognostic factors in patients with nasopharyngeal carcinoma: Neutrophil-lymphocyte ratio and platelet-lymphocyte ratio

BACKGROUND

Pretreatment hematological markers of inflammatory response have emerged as prognostic factors for patients with cancer. In this study, we evaluated the prognostic significance of various hematologic parameters in patients with nasopharyngeal carcinoma (NPC).

METHODS

Clinical data from 251 patients with NPC were retrospectively collected. Neutrophil counts, lymphocyte counts, platelet counts, neutrophil-lymphocyte ratio (NLR), and platelet-lymphocyte ratio (PLR) were adopted as potential prognostic biomarkers. The Kaplan-Meier method and log-rank test were adopted to calculate and compare the progression-free survival (PFS) and overall survival (OS) rates. The Cox proportional hazards model was used to carry out univariate and multivariate analyses.

RESULTS

NLR ≥2.7 (hazard ratio [HR] = 2.01; 95% confidence interval [CI] = 1.23-3.29; p = .005) and PLR ≥167.2 (HR = 2.12; 95% CI = 1.35-3.33; p = .001) were significantly associated with shorter PFS, whereas PLR ≥163.4 (HR = 2.64; 95% CI = 1.25-5.60; p = .011) was correlated with poor OS.

CONCLUSION

Pretreatment NLR and PLR can be independent prognostic factors for patients with NPC. © 2015 Wiley Periodicals, Head Neck 38: E1332-E1340, 2016.

Decreased circulating and neutrophil mediated VEGF-A165 release in stable long-term cardiac transplant recipients

Background

Vascular endothelial growth factor (VEGF) may play a role on the allograft remodelling following cardiac transplantation (CTx). We measured the circulating levels of VEGF-A₁₆₅ concomitantly with the proinflammatory (Interleukin-8; IL-8), anti-inflammatory (IL-1 receptor antagonist; IL-1RA) and their release from neutrophils of CTx recipients.

Methods

Eighteen CTx recipients aged 49.6 ± 3.1 years, being transplanted for 145 ± 20 months were age-matched to 35 healthy control (HC) subjects. Concomitantly to plasma assessment, circulating neutrophils were isolated, purified and stimulated by vehicle (PBS), N-formyl-Met-Leu-Phe (fMLP, 10⁻⁷ M), bacterial lipopolysaccharide (LPS, 1 μg/mL), or tumour necrosis factor alpha (TNF-α, 10 ng/mL).

Results

Compared with HC, CTx recipients exhibited a decrease (−80%) in plasmatic levels of VEGF-A₁₆₅ (225 ± 42 (HC) vs 44 ± 10 pg/mL (CTx); (p < 0.001). There were no differences in the levels of IL-8 and IL-1RA. Under basal or stimulated conditions, neutrophils from CTx patients exhibited a marked decrease ranging from −30 to −88% on their capacity to release VEGF-A₁₆₅, IL-8 and IL-1RA upon stimulation.

Conclusions

Long-term CTx recipients exhibit a marked reduction in the circulating levels of VEGF-A₁₆₅, as well as neutrophil-mediated release of VEGF-A₁₆₅, IL-1RA and IL-8 compared to healthy volunteers. The mechanisms and physiological impacts of these findings deserve additional investigations.

Neutrophil-to-lymphocyte and platelet-to-lymphocyte ratios as predictors of survival and metastasis for recurrent hepatocellular carcinoma after transarterial chemoembolization

Purpose

To evaluate whether neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) predict survival and metastasis in patients after transarterial chemoembolization (TACE) for recurrent hepatocellular carcinoma (RHCC).

Materials and Methods

Clinical and laboratory data from 132 RHCC patients treated with TACE from January 2003 to December 2012 were retrospectively reviewed. Prognostic factors were assessed by multivariate analysis, and the predictive values of NLR and PLR for overall survival (OS) and extrahepatic metastases were compared.

Results

Pretreatment mean NLR and PLR were 3.1 and 137, respectively. The 0.5-, 1-, and 2-year OS rates were 93.7%, 67.1%, and 10.1% in the low NLR group and 81.1%, 18.9%, and 3.8% in the high NLR group, respectively (P = 0.017). The corresponding OS rates in the low and high PLR groups were 92.5%, 58.1%, and 9.7% and 84.6%, 23.1%, and 2.6%, respectively (P = 0.030). The discriminatory performance predicting 1-year survival probability was significantly poorer for NLR (area under the curve [AUC] = 0.685, 95% confidence interval [CI] 0.598–0.763) than for PLR (AUC = 0.792, 95% CI 0.712–0.857; P = 0.0295), but was good for both ratios for predicting post-TACE extrahepatic metastasis. Multivariate analysis indicated that high PLR (hazard ratio [HR] = 0.373, 95% CI = 0.216-0.644, P < 0.001, vascular invasion (HR = 0.507, 95% CI = 0.310–0.832, P = 0.007), and multiple tumors (HR= 0.553, 95% CI = 0.333–0.919, P = 0.022) were independent prognostic factors for OS.

Conclusions

High NLR and PLR were both associated with poor prognosis and metastasis in RHCC patients treated with TACE, but high PLR was a better predictor of 1-year OS. High PLR, vascular invasion, and multiple tumors were independent, unfavorable prognostic factors.

Neutrophil-to-lymphocyte ratio acts as a prognostic factor for patients with advanced hepatocellular carcinoma

Few studies investigated the prognosis of patients with advanced hepatocellular carcinoma (aHCC). This study was aimed to determine the prognostic value of differential blood cell counts including blood white cells, neutrophil, lymphocyte, neutrophil-lymphocyte ratio (NLR), and platelet in patients with aHCC. A total of 205 ethnic Chinese aHCC patients receiving non-systematic sorafenib were analyzed retrospectively. The prognostic value of differential blood cell counts and NLR for overall survival (OS) was determined by integration into Cancer of the Liver Italian Program (CLIP) score system using backward elimination model of multivariate Cox regression. As a result, NLR was confirmed to be an independent predictor for OS (p = 0.001) with the rest parameters presented negative results. Then, aHCC patients were dichotomized into two groups according to NLR values ≤ 2.43 or >2.43. Patients with low NLR presented lower CLIP score and higher 6-month survival rate (56.1 vs 25.9%) compared with patients with high NLR level. Besides, low NLR level was associated with favorable prognostic factors such as lower α-fetoprotein, alkaline phosphatase, and total bilirubin, as well as decreased incidence of ascites, portal vein thrombosis, and metastasis. Besides, low NLR level was associated less white cells and neutrophil granulocytes, as well as more lymphocyte. In summary, the present study firstly indentified NLR as an independent prognostic factor in aHCC patients receiving no systematic sorafenib.

Effect of everolimus on the immunomodulation of the human neutrophil inflammatory response and activation

The primary cause of mortality at 5 years following a cardiac transplantation is the development of atherosclerosis, termed coronary allograft vasculopathy (CAV). This pathology is characterized by diffused intimal hyperplasia and emanates from coronary arterial injuries caused by immune inflammatory cells. Neutrophils play an important role in this inflammatory process; however, their potential participation in the pathogenesis of CAV is poorly understood. Despite their essential contribution to the prevention of graft rejection, immunosuppressive drugs could have detrimental effects owing to their pro-inflammatory activities. Thus, we investigated the impact of different immunosuppressive drugs on the inflammatory response of neutrophils isolated from the blood of healthy volunteers. Under basal conditions, mammalian target of rapamycin (mTOR) inhibitors (sirolimus and everolimus) had the most potent anti-inflammatory effect, decreasing both IL-8 release (≈−80%) and vascular endothelial growth factor (VEGF) release (≈−65%) and preserving the release of the anti-inflammatory cytokine interleukin-1 receptor antagonist (IL-1RA). In TNF-α-treated neutrophils, pre-incubation with everolimus provided the most potent effect, simultaneously reducing the release of both VEGF and IL-8 while doubling the release of IL-1RA. This latter effect of everolimus was maintained even when administered in combination with other immunosuppressive drugs. Sirolimus and everolimus decreased the tumor necrosis factor (TNF)-α-induced adhesion of neutrophils to human endothelial cells and human extracellular matrix. This effect was largely dependent on the ability of these compounds to alter β₂-integrin/CD18 activation. Our results suggest a potential mechanism for the beneficial effect of everolimus in the prevention of CAV in heart transplant recipients.

Neutrophil-lymphocyte ratio as a predictor of outcomes for patients with hepatocellular carcinoma undergoing TAE combined with Sorafenib

The aim of this study was to investigate the prognostic significance of blood NLR in patients with intermediate-advanced hepatocellular carcinoma (HCC) who received transcatheter arterial embolization (TAE) combined with Sorafenib. A total of 40 patients with intermediate-advanced HCC from January 1, 2010, through May 31, 2013, treated with concurrent TAE in combination with Sorafenib were admitted to this study in our hospital. Potential prognostic factors, including serum NLR, were analyzed. The pretreatment mean NLR was 3.0; 21 (52.5 %) patients with elevated high NLR (>3.0). The median survival of patients with a high NLR was 14 months (95 % CI 10.1-17.9 months) compared with 26 months (95 % CI 17.4-34.6 months) for patients with a low NLR; a significant difference was found in overall survival (P = 0 0.001). Barcelona Clinical Liver Cancer staging classification and NLR >3.0 were all predictors of poorer over survival. Multivariate analysis showed that high NLR was independent factors associated with worse survival. A high periprocedural NLR independently predicts poor survival in patients with unresectable HCC undergoing TAE combined with Sorafenib.

Angiopoietins in inflammation and their implication in the development of inflammatory bowel disease. A review

BACKGROUND

Angiopoietins are essential angiogenic mediators. Since inflammatory bowel disease (IBD) involves inflammation, ulceration and regeneration of the intestinal mucosa, the angiopoietin system has been proposed as a factor to maintain pathological angiogenesis during the development of the IBD.

AIM

To review the potential role of angiopoietins in the inflammation driven by angiogenesis during the course of the IBD.

METHODS

Publications were identified by PubMed searches using the following key words: angiopoietin; Tie-2 receptor; angiogenesis; inflammatory bowel disease and inflammation, in various combinations.

RESULTS

Angiopoietin-1 acts as a regulator of blood vessel maturation and has anti-inflammatory properties, whereas angiopoietin-2 marks the onset of angiogenesis and is required for normal formation of lymph vessels. Both angiopoietins make use of their angiogenic regulatory effects via the angiopoietin tyrosine-kinase receptor (Tie-2). While angiogenesis has been shown to promote and sustain many events of inflammation, the involvement of the angiopoietin system in IBD has been reported in few studies. It is not clear whether the angiopoietins' role in the development of intestinal inflammation is due to an imbalance in the levels of these proteins or this system exerts its pro-angiogenic properties through a different mechanism during the close-loop relationship between angiogenesis and inflammation.

CONCLUSIONS

Angiopoietins have key functions in the angiogenic process, and their abnormal activation might depend on their surrounding inflamed environment. The determination of these angiogenic factors in serum and tissue could be useful for monitoring IBD progression.

Angiopoietin-1 upregulates de novo expression of IL-1β and Il1-Ra, and the exclusive release of Il1-Ra from human neutrophils

The expression of the angiopoietin (Ang) receptor, Tie2, on both endothelial and inflammatory cells supports the idea that Ang signaling may play a fundamental role in initiating and maintaining the inflammatory response. We have previously shown that Ang1 and/or Ang2 alter the innate immune response by enhancing human neutrophil survival, chemotaxis and production of inflammatory cytokine interleukin-8 (IL-8) in vitro. Thus, we hypothesized that Ang1 and Ang2 could modulate other inflammatory signals in neutrophils, a possibility we explored through a gene-based assay looking at changes in the mRNA expression of 84 inflammatory cytokines and their receptors. We observed that Ang1 (10(-8) M), but not Ang2, increased mRNA expression of prominent pro-inflammatory cytokine IL-1β and its natural antagonist IL-1RA, by up to 32.6- and 10.0-fold respectively, compared to PBS-control. The effects of Ang1 extended to the proteins, as Ang1 increased intracellular levels of precursor and mature IL-1β, and extracellular levels of IL-1RA proteins, by up to 4.2-, 5.0- and 4.4-fold respectively, compared to PBS-control. Interestingly, Ang1 failed at inducing IL-1β protein release or at increasing intracellular IL-1RA, but the ratio of IL-1RA to mature IL-1β remained above 100-fold molar excess inside and outside the cells. The above-noted effects of Ang1 were mediated by MAP kinases, whereby inhibiting MEK1/2 lead to up to 70% effect reduction, whereas the blockade of p38MAPK activity doubled Ang1's effect. These findings suggest that Ang1 selectively alters the balance of neutrophil-derived inflammatory cytokines, favoring the blockade of IL-1 activity, a consideration for future therapies of inflammatory diseases.

On the cytokines produced by human neutrophils in tumors

Although traditionally viewed as short-lived innate immunity cells, only playing a crucial role in host defense toward infections, neutrophils have recently become subject of a new wave of research in diverse areas including in tumors. Indeed, increasing experimental evidence indicate that neutrophils may directly or indirectly influence the tumor fate through the release of a wide array of molecules able to exert either pro-tumor or anti-tumor functions depending on the microenvironment milieu, including cytokines. This review therefore attempts to uncover the role that neutrophils play during the different steps of tumor development (from promotion to progression), as well as in anti-tumor responses, via cytokine production.

Fixing the leak: targeting the vascular endothelium in sepsis

Angiopoietin-1 is a Tie-2 receptor agonist that stabilizes vascular endothelium, promoting endothelial maturation and preventing capillary leak. Angiopoietin-2 is largely a competitive partial antagonist that is markedly elevated in humans and animal models of sepsis and other inflammatory states, directly disrupts the endothelial barrier, and has been correlated with end-organ dysfunction and death in sepsis. In the previous issue of Critical Care, Alfieri and colleagues used intravital microscopy to study the microvasculature in a murine model of sepsis. Treatment with a modified angiopoietin-1 molecule led to reversal of albumin vascular leak and improved blood flow to skeletal muscle, as well as a decrease in the levels of several inflammatory cytokines. Importantly, the angiopoietin-1 variant was administered 20 hours after initial lipopolysaccharide challenge. This study adds to the evidence that the angiopoietin/Tie-2 axis represents a modifiable pathway through which targeted therapy may be able to directly reverse part of the pathology of sepsis.

Autocrine role of angiopoietins during megakaryocytic differentiation

The tyrosine kinase Tie-2 and its ligands Angiopoietins (Angs) transduce critical signals for angiogenesis in endothelial cells. This receptor and Ang-1 are coexpressed in hematopoietic stem cells and in a subset of megakaryocytes, though a possible role of angiopoietins in megakaryocytic differentiation/proliferation remains to be demonstrated. To investigate a possible effect of Ang-1/Ang-2 on megakaryocytic proliferation/differentiation we have used both normal CD34(+) cells induced to megakaryocytic differentiation and the UT7 cells engineered to express the thrombopoietin receptor (TPOR, also known as c-mpl, UT7/mpl). Our results indicate that Ang-1/Ang-2 may have a role in megakaryopoiesis. Particularly, Ang-2 is predominantly produced and released by immature normal megakaryocytic cells and by undifferentiated UT7/mpl cells and slightly stimulated TPO-induced cell proliferation. Ang-1 production is markedly induced during megakaryocytic differentiation/maturation and potentiated TPO-driven megakaryocytic differentiation. Blocking endogenously released angiopoietins partially inhibited megakaryocytic differentiation, particularly for that concerns the process of polyploidization. According to these data it is suggested that an autocrine angiopoietin/Tie-2 loop controls megakaryocytic proliferation and differentiation.

Characterization of FGF receptor expression in human neutrophils and their contribution to chemotaxis

Several members of the fibroblast growth factor (FGF) family are potent endothelial cell (EC) mitogens and angiogenic factors, and their activities can be mediated by four tyrosine kinase receptors (FGFR1–4). In addition, FGFs can induce the release of inflammatory mediators by ECs and the expression of adhesion molecules at their surface, thereby favoring the recruitment and transvascular migration of inflammatory cells such as neutrophils. Neither the expression nor the biological activities that could be mediated by FGFRs have been investigated in human neutrophils. By biochemical and cytological analyses, we observed that purified circulating human neutrophils from healthy individuals expressed varying levels of FGFRs in their cytosol and at their cytoplasmic membrane. FGFR-2 was identified as the sole cell surface receptor, with FGFR-1 and -4 localizing in the cytosol and FGFR-3 being undetectable. We assessed the capacity of FGF-1 and FGF-2 to induce neutrophil chemotaxis in a modified Boyden microchamber and observed that they increase neutrophil transmigration at 10−10 and 10−9 M and by 1.77- and 2.34-fold, respectively, as compared with PBS-treated cells. Treatment with a selective anti-FGFR-2 antibody reduced FGF-1-mediated chemotaxis by 75% and abrogated the effect of FGF-2, while the blockade of FGFR-1 and -4 partially inhibited (15–40%) FGF-chemotactic activities. In summary, our data are the first to report the expression of FGF receptors in human neutrophils, with FGF-1 and FGF-2 promoting neutrophil chemotaxis mainly through FGFR-2 activation.

Blood neutrophil-to-lymphocyte ratio predicts survival in patients with unresectable hepatocellular carcinoma undergoing transarterial chemoembolization

PURPOSE

To evaluate whether the neutrophil-to-lymphocyte ratio (NLR) predicts survival in patients with unresectable hepatocellular carcinoma (HCC) before and after transarterial chemoembolization treatment.

MATERIALS AND METHODS

Clinical and laboratory data for 145 consecutive patients undergoing transarterial chemoembolization for unresectable HCC during 2001-2004 were analyzed retrospectively. The NLR was recorded before and 3 days after treatment.

RESULTS

The pretreatment mean NLR was 3.3; 59 (40.7%) patients had an elevated NLR (≥ 3.3). The median survival of patients with a high NLR was 8 months (range 1-28 months) compared with 12 months (range 2-41 months) for patients with a normal NLR; a significant difference was found in overall survival (log-rank test, P = .001). The NLR was increased in 127 (87.6%) patients after transarterial chemoembolization and was decreased in 18 patients; the increase indicated better outcomes (log-rank test, P = .006). Age (≥ 49 y), high NLR, decreased NLR after treatment, large tumor (≥ 5 cm), vascular invasion, and elevated serum α-fetoprotein (AFP) level all were predictors of poor survival. Multivariate analysis showed that a high NLR (P = .041) and vascular invasion (P = .040) were independent factors for predicting worse survival.

CONCLUSIONS

A high NLR independently predicts poor survival in patients with unresectable HCC undergoing transarterial chemoembolization treatment, and an increased NLR indicates a better outcome than a decreased NLR for patients after transarterial chemoembolization.

Angiopoietin-2-driven vascular remodeling in airway inflammation

Vascular remodeling is a feature of chronic inflammation during which capillaries transform into venules that expand the region of the vasculature in which leakage and leukocyte emigration both occur. Recently, we found that angiopoietin/Tie2 receptor signaling drives the transformation of capillaries into venules at an early stage of the sustained inflammatory response in the airways of mice infected with Mycoplasma pulmonis. However, the precise contributions of both angiopoietin-1 (Ang1) and angiopoietin-2 (Ang2) are not clear. In this study, we sought to determine the contribution of Ang2 to this vascular remodeling. Ang2 mRNA expression levels increased and phosphorylated Tie2 immunoreactivity in mucosal blood vessels decreased, indicative of diminished receptor signaling after infection. Selective inhibition of Ang2 throughout the infection by administration of either of two distinct function-blocking antibodies reduced the suppression of Tie2 phosphorylation and decreased the remodeling of mucosal capillaries into venules, the amount of leukocyte influx, and disease severity. These findings are consistent with Ang2 acting as an antagonist of Tie2 receptors and the reduction of Tie2 phosphorylation in endothelial cells rendering the vasculature more responsive to cytokines that promote both vascular remodeling and the consequences of inflammation after M. pulmonis infection. By blocking such changes, Ang2 inhibitors may prove beneficial in the treatment of sustained inflammation in which vascular remodeling, leakage, and leukocyte influx contribute to its pathophysiology.

Angiopoietins, abdominal aortic aneurysm and atherosclerosis

Abdominal aortic aneurysm (AAA) and atherosclerosis are common causes of mortality and morbidity in an aging population. Angiogenesis is believed to contribute to the development and progression of these diseases. Angiopoietins (angpts) are known to be important regulators of angiogenesis. Angpts can also influence inflammation and have been shown to possess both pro-atherosclerotic and atheroprotective effects. This review explores the potential roles that the angpts play in the development and progression of AAA and atherosclerosis.

Amniotic fluid angiopoietin-1, angiopoietin-2, and soluble receptor tunica interna endothelial cell kinase-2 levels and regulation in normal pregnancy and intraamniotic inflammation-induced preterm birth

BACKGROUND

Angiopoietin-1 (Ang-1) and Ang-2 act selectively on endothelial cells by engaging the Tunica interna endothelial cell kinase-2 (Tie2) receptor. A soluble form of Tie2 (sTie2) blocks angiopoietin bioactivity.

OBJECTIVE

The aim of the study was to characterize changes and expression patterns of Ang-1, Ang-2, and sTie2 in amniotic fluid (AF) and placenta during human pregnancy and intraamniotic inflammation (IAI)-induced preterm birth.

DESIGN AND SETTING

We conducted a cross-sectional study at a tertiary university hospital.

PATIENTS

AF levels of Ang-1, Ang-2, and sTie2 were evaluated in 176 women during second trimester (n = 40), third trimester (n = 37), and preterm labor (positive IAI, n = 50; negative IAI, n = 49). Placenta and cord blood of select women were analyzed.

MAIN OUTCOME MEASURES

Ang-1, Ang-2, sTie2, and IL-6 were evaluated by ELISA. Real-time PCR measured Ang-1, Ang-2, and Tie2 placental mRNA levels. Placenta was immunostained for Ang-1 and Ang-2. Placental explant cultures were stimulated with lipopolysaccharide, Pam3Cys, and modulators of protein synthesis/secretion (cycloheximide, monensin, and brefeldin A).

RESULTS

In normal pregnancy, the levels and ratios of AF Ang-1, Ang-2, and sTie2 varied with gestational age (GA) (P < 0.001). PCR revealed corresponding changes in placental Ang-1 and Ang-2, but not Tie2, mRNA. IAI raised AF Ang-1, Ang-2, and sTie2 above the expected level for GA without affecting their placental mRNA. Ang-2 immunoreactivity appeared enhanced in areas of villous edema. AF Ang-2/Ang-1 ratio was an important determinant of cord blood IL-6 (P < 0.001). Ex-vivo, sTie2 release was increased by Golgi disrupting but not bacterial mimic agents.

CONCLUSIONS

Ang-1, Ang-2, and sTie2 are physiological constituents of AF that are GA and IAI regulated. Ang-2/Ang-1 ratio may play a role in modulating the fetal inflammatory response to IAI. Placental sTie2 shedding likely involves a Golgi-mediated mechanism.

Angiopoietin/Tie2 signaling transforms capillaries into venules primed for leukocyte trafficking in airway inflammation

Vascular endothelial growth factor (VEGF) is a key angiogenic factor in tumors, but less is known about what drives vascular remodeling in inflammation, where plasma leakage and leukocyte influx are prominent features. In chronic airway inflammation in mice infected by the bacterium Mycoplasma pulmonis (M. pulmonis), the segment of the microvasculature that supports leukocyte adhesion and migration expands through remodeling of capillaries into vessels with features of venules. Here, we report that the angiopoietin/Tie2 pathway is an essential driving force for capillary remodeling into venules in M. pulmonis-infected mouse airways. Similar to M. pulmonis infection, systemic overexpression of angiopoietin-1 (Ang1) resulted in remodeling of airway capillaries into venular-like vessels that expressed venous markers like P-selectin, ICAM-1, and EphB4 and were sites of leukocyte adhesion during lipopolysaccharide-induced acute inflammation. Ang1 and Ang2 protein increased in M. pulmonis-infected mouse airways but came from different cellular sources: Ang1 was expressed in infiltrating neutrophils and Ang2 in endothelial cells. Indeed, systemic administration of soluble Tie2 inhibited capillary remodeling, induction of venous markers, and leukocyte influx in M. pulmonis-infected mouse airways. Together, these findings suggest that blockade of the Ang/Tie2 pathway may represent a therapeutic approach in airway inflammation.