Vasculotide, an Angiopoietin-1 mimetic, ameliorates several features of experimental atopic dermatitis-like disease

Vasculotide restores the blood-brain barrier after focused ultrasound-induced permeability in a mouse model of Alzheimer's disease

Focused ultrasound (FUS) is used to locally and transiently induce blood-brain barrier (BBB) permeability, allowing targeted drug delivery to the brain. The purpose of the current study is to evaluate the potential of Vasculotide to accelerate the recovery of the BBB following FUS disruption in the TgCRND8 mouse model of amyloidosis, characteristic of Alzheimer's disease (AD). Accelerating the restoration of the BBB post-FUS would represent an additional safety procedure, which could be beneficial for clinical applications. Methods: TgCRND8 mice and their non-transgenic littermates were treated with Vasculotide (250 ng, intraperitoneal) every 48 hours for 3 months. BBB permeability was induced using FUS, in presence of intravenously injected microbubbles, in TgCRND8 and non-transgenic mice, and confirmed at time 0 by MRI enhancement using the contrast agent gadolinium. BBB closure was assessed at 6, 12 and 20 hours by MRI. In a separate cohort of animals, BBB closure was assessed at 24-hours post-FUS using Evans blue injected intravenously and followed by histological evaluation. Results: Chronic Vasculotide administration significantly reduces the ultra-harmonic threshold required for FUS-induced BBB permeability in the TgCRND8 mice. In addition, Vasculotide treatment led to a faster restoration of the BBB following FUS in TgCRND8 mice. BBB closure after FUS is not significantly different between TgCRND8 and non-transgenic mice. BBB permeability was assessed by gadolinium up to 20-hours post-FUS, demonstrating 87% closure in Vasculotide treated TgCRND8 mice, as opposed to 52% in PBS treated TgCRND8 mice, 58% in PBS treated non-transgenic mice, and 74% in Vasculotide treated non-transgenic mice. In both TgCRND8 mice and non-transgenic littermates the BBB was impermeable to Evans blue dye at 24-hours post-FUS. Conclusion: Vasculotide reduces the pressure required for microbubble ultra-harmonic onset for FUS-induced BBB permeability and it accelerates BBB restoration in a mouse model of amyloidosis, suggesting its potential clinical utility to promote vascular health, plasticity and repair in AD.

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.

Role of Angiopoietin-2 in Vascular Physiology and Pathophysiology

Angiopoietins 1–4 (Ang1–4) represent an important family of growth factors, whose activities are mediated through the tyrosine kinase receptors, Tie1 and Tie2. The best characterized are angiopoietin-1 (Ang1) and angiopoietin-2 (Ang2). Ang1 is a potent angiogenic growth factor signaling through Tie2, whereas Ang2 was initially identified as a vascular disruptive agent with antagonistic activity through the same receptor. Recent data demonstrates that Ang2 has context-dependent agonist activities. Ang2 plays important roles in physiological processes and the deregulation of its expression is characteristic of several diseases. In this review, we summarize the activity of Ang2 on blood and lymphatic endothelial cells, its significance in human physiology and disease, and provide a current view of the molecular signaling pathways regulated by Ang2 in endothelial cells.

Angiogenic Self-Assembling Peptide Scaffolds for Functional Tissue Regeneration

Implantation of acellular biomimetic scaffolds with proangiogenic motifs may have exciting clinical utility for the treatment of ischemic pathologies such as myocardial infarction. Although direct delivery of angiogenic proteins is a possible treatment option, smaller synthetic peptide-based nanostructured alternatives are being investigated due to favorable factors, such as sustained efficacy and high-density epitope presentation of functional moieties. These peptides may be implanted in vivo at the site of ischemia, bypassing the first-pass metabolism and enabling long-term retention and sustained efficacy. Mimics of angiogenic proteins show tremendous potential for clinical use. We discuss possible approaches to integrate the functionality of such angiogenic peptide mimics into self-assembled peptide scaffolds for application in functional tissue regeneration.

Variation in the TEK gene is not associated with asthma but with allergic conjunctivitis

The Tie2 receptor is an important player in angiogenesis. The Tie2 mRNA and protein are abundantly expressed in the lungs and the associated pathway also has an important role in the development and function of the eye. Tie2 is encoded by the TEK gene in humans. Recently, variations in the TEK gene have been found associated with asthma. The objective of the present study was to investigate whether variations in the TEK gene influenced the susceptibility to pediatric asthma and/or associated phenotypes like GINA status, viral- or exercise-induced asthma, allergic asthma, indoor, outdoor, inhalative allergies, IgE and eosonophil levels, allergic rhinitis and allergic conjunctivitis. Three single nucleotide polymorphisms (SNPs, rs3780315, rs581724 and rs7876024) in the TEK gene were genotyped in 1189 unrelated individuals, out of which 435 were asthmatic children and 754 healthy controls. Different types of asthma, allergies and co-morbidities were defined in 320 patients. Among the fully phenotyped 320 asthmatic patients 178 (55.6%) also had allergic rhinitis and 100 (31.3%) had conjunctivitis. Among the rhinitis patients 98 (55.1%) also had conjunctivitis. Two patients had conjunctivitis without rhinitis. The genotyped SNPs showed no association with asthma. However, SNP rs581724 was significantly associated with allergic conjunctivitis in a recessive way (p=0.007; OR=2.3 (1.3-4.4)) within the asthmatic population. The risk remained significant when the whole population (asthmatics and healthy controls) was included in the calculation (p = 0.003; OR = 2.1 (1.3-3.6)). The minor allele of the rs581724 SNP which is associated with the increased risk to conjunctivitis is also associated with reduced Tie2 expression. There was a significant association between SNP rs581724 and the occurrence of allergic conjunctivitis in asthmatic children. If additional studies can confirm the role of the Tie2 pathway in allergic conjunctivitis, it can be a potential novel therapeutic target in the disease.