Circulating angiopoietin-1 and -2 in patients with stable and exacerbated asthma

Pericyte loss leads to microvessel remodeling and nasal polyp formation

BACKGROUND

Chronic rhinosinusitis (CRS) may be caused by increased vascular permeability and inflammatory cell leakage in the subepithelial tissue.

AIMS/OBJECTIVES

The aim of this study is to clarify the role of pericytes in tissue edema, microvessel dysfunction and vascular remodeling mechanisms in patients of CRS with nasal polyps (CRSwNP).

MATERIAL AND METHODS

A total of 63 tissue samples were collected, including 42 CRSwNP samples (22 eosinophilic CRSwNP (eCRSwNP) and 20 non-eosinophilic CRSwNP (non-eCRSwNP) samples) and 21 samples of CRS without nasal polyps (CRSsNP). The samples were stained by immunofluorescence to measure microvessel density (MVD) and microvessel pericyte coverage index (MPI).

RESULTS

We found that the albumin expression in the eCRSwNP group was significantly increased (p < .05). The MPI was significantly decreased (p <.05). There was a significant negative correlation between the MPI and the plasma albumin level (r=-0.82, p < .05). The MPI was negatively correlated with eosinophilic count (r=-0.77, p < .05). In the eCRSwNP group, the expressions of IL-4, Ang-1 and Ang-2 were increased compared with those in the control group.

CONCLUSIONS AND SIGNIFICANCE

Pericyte loss may induce microvessel dysfunction, affect the development of interstitial edema and eosinophilic exosmosis in eCRSwNP, and contribute to the formation and maintenance of nasal polyps.

Targeting the Angiopoietin/Tie Pathway: Prospects for Treatment of Retinal and Respiratory Disorders

Anti-angiogenic approaches have significantly advanced the treatment of vascular-related pathologies. The ephemeral outcome and known side effects of the current vascular endothelial growth factor (VEGF)-based anti-angiogenic treatments have intensified research on other growth factors. The angiopoietin/Tie (Ang/Tie) family has an established role in vascular physiology and regulates angiogenesis, vascular permeability, and inflammatory responses. The Ang/Tie family consists of angiopoietins 1-4, their receptors, tie1 and 2 and the vascular endothelial-protein tyrosine phosphatase (VE-PTP). Modulation of Tie2 activation has provided a promising outcome in preclinical models and has led to clinical trials of Ang/Tie-targeting drug candidates for retinal disorders. Although less is known about the role of Ang/Tie in pulmonary disorders, several studies have revealed great potential of the Ang/Tie family members as drug targets for pulmonary vascular disorders as well. In this review, we summarize the functions of the Ang/Tie pathway in retinal and pulmonary vascular physiology and relevant disorders and highlight promising drug candidates targeting this pathway currently being or expected to be under clinical evaluation for retinal and pulmonary vascular disorders.

Serum angiopoietin-2 level as a novel biomarker in atopic dermatitis

BACKGROUND

Atopic dermatitis (AD) is a chronic, pruritic inflammatory skin disease. Angiopoietin is an intrinsic mediator induced by T helper 2 cytokines and has been reported it to play a critical role in the pathogenesis of AD.

OBJECTIVES

To determine the relationship between circulating angiopoietin-2 (Ang-2) in AD patients and to determine its correlation with the severity and chronicity of the disease.

METHODS

The present study included 38 AD patients and 38 healthy controls, age- and sex-matched. We collected 3 mm of venous blood from each subject. Enzyme-linked immunosorbent assay (ELISA) determined serum angiopoietin. We determined the correlation between serum Ang-2 level, duration of disease, severity, type of atopy, and scoring atopic dermatitis (SCORAD) score.

RESULTS

There were highly significant differences between patients and controls with regard to serum Ang-2 levels (P < 0.001). There were significant differences between severe AD patients with serum Ang-2 levels with an increasing level of degree severity (P < 0.001). There were significant differences in serum Ang-2 levels among widespread type (P < 0.03). There was a positive significant correlation between Ang-2 levels and both duration and SCORAD score of the patient group.

CONCLUSION

Serum Ang-2 levels may correlate with disease severity, chronicity in patients with AD, and serve as a potential biomarker of the disease severity.

Dysregulation of circulating sTie2 and sHER2 in HIV-infected women with preeclampsia

OBJECTIVE

This study assesses whether circulating sTie2 and sHER2 are altered in HIV-negative and HIV-positive pregnant normotensive and preeclamptic women.

METHODS

Serum samples were obtained from 80 pregnant women, stratified into four groups, namely, HIV-negative normotensives (20); HIV-positive normotensives (20); HIV-negative preeclamptics (20); and HIV-positive preeclamptics (20). The concentration of sTie2 and sHER2 was analyzed by Bio-Plex multiplex immunoassay and generated from a standard curve.

RESULTS

sTie2 differed significantly by pregnancy type (p = 0.0403) but not by HIV status (p = 0.5214). sHER2 did not show a significant difference between normotensive and preeclampsia (p = 0.3677) and by HIV status (p = 0.5249).

CONCLUSION

Irrespective of HIV status, reduced concentrations of sTie2 were evident in preeclampsia (PE) reflecting a dysregulation of the angiogenic process. sHER2 was similar between pregnancy types, attributable to the oxidative stressed microenvironment which promotes dysregulation of the MAPK and P13K/Akt signaling. HIV status did not influence sTie2 and sHER2 expression, reflecting the immune reconstitution of highly active antiretroviral therapy. sTie2 and sHER2 were not influenced by PE comorbid with HIV infection.

Endothelial Activation: The Ang/Tie Axis in Sepsis

Sepsis, a dysregulated host response to infection that causes life-threatening organ dysfunction, is a highly heterogeneous syndrome with no specific treatment. Although sepsis can be caused by a wide variety of pathogenic organisms, endothelial dysfunction leading to vascular leak is a common mechanism of injury that contributes to the morbidity and mortality associated with the syndrome. Perturbations to the angiopoietin (Ang)/Tie2 axis cause endothelial cell activation and contribute to the pathogenesis of sepsis. In this review, we summarize how the Ang/Tie2 pathway is implicated in sepsis and describe its prognostic as well as therapeutic utility in life-threatening infections.

The role of the endothelium in asthma and chronic obstructive pulmonary disease (COPD)

COPD and asthma are important chronic inflammatory disorders with a high associated morbidity. Much research has concentrated on the role of inflammatory cells, such as the neutrophil, in these diseases, but relatively little focus has been given to the endothelial tissue, through which inflammatory cells must transmigrate to reach the lung parenchyma and cause damage. There is evidence that there is an abnormal amount of endothelial tissue in COPD and asthma and that this tissue and its’ progenitor cells behave in a dysfunctional manner. This article reviews the evidence of the involvement of pulmonary endothelium in COPD and asthma and potential treatment options for this.