Study of the Structure of Hyperbranched Polyglycerol Coatings and Their Antibiofouling and Antithrombotic Applications.

While blood-contacting materials are widely deployed in medicine in vascular stents, catheters, and cannulas, devices fail in situ because of thrombosis and restenosis. Furthermore, microbial attachment and biofilm formation is not an uncommon problem for medical devices. Even incremental improvements in hemocompatible materials can provide significant benefits for patients in terms of safety and patency as well as substantial cost savings.

Desmoglein-2 is important for islet function and β-cell survival.

Type 1 diabetes is a complex disease characterized by the lack of endogenous insulin secreted from the pancreatic β-cells. Although β-cell targeted autoimmune processes and β-cell dysfunction are known to occur in type 1 diabetes, a complete understanding of the cell-to-cell interactions that support pancreatic function is still lacking. To characterize the pancreatic endocrine compartment, we studied pancreata from healthy adult donors and investigated a single cell surface adhesion molecule, desmoglein-2 (DSG2).

Attachment of endothelial colony-forming cells onto a surface bearing immobilized anti-CD34 antibodies: Specific CD34 binding versus nonspecific binding.

Cardiovascular disease is a leading cause of death worldwide; however, despite substantial advances in medical device surface modifications, no synthetic coatings have so far matched the native endothelium as the optimal hemocompatible surface for blood-contacting implants. A promising strategy for rapid restoration of the endothelium on blood-contacting biomedical devices entails attracting circulating endothelial cells or their progenitors, via immobilized cell-capture molecules; for example, anti-CD34 antibody to attract CD34+ endothelial colony-forming cells (ECFCs). Inherent is the assumption that the cells attracted to the biomaterial surface are bound exclusively via a specific CD34 binding.

Vasculogenic mimicry structures in melanoma support the recruitment of monocytes.

The progression of cancer is facilitated by infiltrating leukocytes which can either actively kill cancer cells or promote their survival. Our current understanding of leukocyte recruitment into tumors is largely limited to the adhesion molecules and chemokines expressed by conventional blood vessels that are lined by endothelial cells (ECs). However, cancer cells themselves can form their own vascular structures (a process known as vasculogenic mimicry (VM)); but whether they actively participate in the recruitment of leukocytes remains to be elucidated.

The development of tumour vascular networks.

The growth of solid tumours relies on an ever-increasing supply of oxygen and nutrients that are delivered via vascular networks. Tumour vasculature includes endothelial cell lined angiogenesis and the less common cancer cell lined vasculogenic mimicry (VM). To study and compare the development of vascular networks formed during angiogenesis and VM (represented here by breast cancer and pancreatic cancer cell lines) a number of in vitro assays were utilised.

CD36 promotes vasculogenic mimicry in melanoma by mediating adhesion to the extracellular matrix.

Background: The formation of blood vessels within solid tumors directly contributes to cancer growth and metastasis. Until recently, tumor vasculature was thought to occur exclusively via endothelial cell (EC) lined structures (i.e.

Surface-Grafted Hyperbranched Polyglycerol Coating: Varying Extents of Fouling Resistance across a Range of Proteins and Cells.

Hyperbranched polyglycerol (HPG) was previously investigated as a nonfouling hydrophilic grafted layer on biomaterial surfaces, analogous to the well-known poly(ethylene oxide) (PEO), but the range of adsorbing cells and proteins tested was limited and at times the assays used were not the most sensitive. Thus, the questions arise whether HPG-grafted layers can indeed efficiently resist adsorption of a wider range of adsorbing biological entities, and how would different biological entities interact with such a coating. An HPG coating of 25 nm thickness was grafted onto a spin-coated and plasma-treated polystyrene (PS) layer on a silicon wafer substrate; this provided a well-suited system for surface analyses by X-ray photoelectron spectroscopy (XPS), time-of-flight secondary ion mass spectrometry (ToF-SIMS), and atomic force microscopy (AFM), which verified the presence of a uniform, smooth grafted HPG layer.

Platelets disrupt vasculogenic mimicry by cancer cells.

Tumour vasculature supports the growth and progression of solid cancers with both angiogenesis (endothelial cell proliferation) and vasculogenic mimicry (VM, the formation of vascular structures by cancer cells themselves) predictors of poor patient outcomes. Increased circulating platelet counts also predict poor outcome for cancer patients but the influence of platelets on tumour vasculature is incompletely understood. Herein, we show with in vitro assays that platelets did not influence angiogenesis but did actively inhibit VM formation by cancer cell lines.

BMPR2-expressing bone marrow-derived endothelial-like progenitor cells alleviate pulmonary arterial hypertension in vivo.

Background And Objective: Pulmonary arterial hypertension (PAH) is characterized by increased resistance in the distal pulmonary arteries, ultimately leading to right heart failure and, despite the available therapeutics, survival remains poor. Reduced expression of bone morphogenetic protein receptor type 2 (BMPR2) is strongly associated with PAH. Cell therapies are of interest in PAH, but whether this approach can upregulate BMPR2 is not known.

Replica moulded poly(dimethylsiloxane) microwell arrays induce localized endothelial cell immobilization for coculture with pancreatic islets.

PolyJet three-dimensional (3D) printing allows for the rapid manufacturing of 3D moulds for the fabrication of cross-linked poly(dimethylsiloxane) microwell arrays (PMAs). As this 3D printing technique has a resolution on the micrometer scale, the moulds exhibit a distinct surface roughness. In this study, the authors demonstrate by optical profilometry that the topography of the 3D printed moulds can be transferred to the PMAs and that this roughness induced cell adhesive properties to the material.

Affinity Binding of EMR2 Expressing Cells by Surface-Grafted Chondroitin Sulfate B.

The propensity of glycosaminoglycans to mediate cell-cell and cell-matrix interactions opens the door to capture cells, including circulating blood cells, onto biomaterial substrates. Chondroitin sulfate (CS)-B is of particular interest, since it interacts with the receptor (EGF)-like module-containing mucin-like hormone receptor-like 2 precursor (EMR2) displayed on the surface of leukocytes and endothelial progenitor cells. Herein, CS-B and its isomer CS-A were covalently immobilized onto heptylamine plasma polymer films via three different binding chemistries to develop platform technology for the capture of EMR2 expressing cells onto solid carriers.

Porous Silicon-Based Cell Microarrays: Optimizing Human Endothelial Cell-Material Surface Interactions and Bioactive Release.

Porous silicon (pSi) substrates are a promising platform for cell expansion, since pore size and chemistry can be tuned to control cell behavior. In addition, a variety of bioactives can be loaded into the pores and subsequently released to act on cells adherent to the substrate. Here, we construct a cell microarray on a plasma polymer coated pSi substrate that enables the simultaneous culture of human endothelial cells on printed immobilized protein factors, while a second soluble growth factor is released from the same substrate.

A non-canonical role for desmoglein-2 in endothelial cells: implications for neoangiogenesis.

Desmogleins (DSG) are a family of cadherin adhesion proteins that were first identified in desmosomes and provide cardiomyocytes and epithelial cells with the junctional stability to tolerate mechanical stress. However, one member of this family, DSG2, is emerging as a protein with additional biological functions on a broader range of cells. Here we reveal that DSG2 is expressed by non-desmosome-forming human endothelial progenitor cells as well as their mature counterparts [endothelial cells (ECs)] in human tissue from healthy individuals and cancer patients.

Sphingosine 1-phosphate is a ligand for peroxisome proliferator-activated receptor-γ that regulates neoangiogenesis.

Sphingosine 1-phosphate (S1P) is a bioactive lipid that can function both extracellularly and intracellularly to mediate a variety of cellular processes. Using lipid affinity matrices and a radiolabeled lipid binding assay, we reveal that S1P directly interacts with the transcription factor peroxisome proliferator-activated receptor (PPAR)γ. Herein, we show that S1P treatment of human endothelial cells (ECs) activated a luciferase-tagged PPARγ-specific gene reporter by ∼12-fold, independent of the S1P receptors.

Interleukin-3 greatly expands non-adherent endothelial forming cells with pro-angiogenic properties.

Circulating endothelial progenitor cells (EPCs) provide revascularisation for cardiovascular disease and the expansion of these cells opens up the possibility of their use as a cell therapy. Herein we show that interleukin-3 (IL3) strongly expands a population of human non-adherent endothelial forming cells (EXnaEFCs) with low immunogenicity as well as pro-angiogenic capabilities in vivo, making their therapeutic utilisation a realistic option. Non-adherent CD133(+) EFCs isolated from human umbilical cord blood and cultured under different conditions were maximally expanded by day 12 in the presence of IL3 at which time a 350-fold increase in cell number was obtained.

Characterization of a distinct population of circulating human non-adherent endothelial forming cells and their recruitment via intercellular adhesion molecule-3.

Circulating vascular progenitor cells contribute to the pathological vasculogenesis of cancer whilst on the other hand offer much promise in therapeutic revascularization in post-occlusion intervention in cardiovascular disease. However, their characterization has been hampered by the many variables to produce them as well as their described phenotypic and functional heterogeneity. Herein we have isolated, enriched for and then characterized a human umbilical cord blood derived CD133(+) population of non-adherent endothelial forming cells (naEFCs) which expressed the hematopoietic progenitor cell markers (CD133, CD34, CD117, CD90 and CD38) together with mature endothelial cell markers (VEGFR2, CD144 and CD31).

Over-expression of sphingosine kinase-1 enhances a progenitor phenotype in human endothelial cells.

Objectives: The use of endothelial progenitor cells in vascular therapies has been limited due to their low numbers present in the bone marrow and peripheral blood. The aim of this study was to investigate the effect of sphingosine kinase on the de-differentiation of mature human endothelial cells toward a progenitor phenotype.

Methods: The lipid enzyme sphingosine kinase-1 was lentivirally over-expressed in human umbilical vein endothelial cells and cells were analyzed for progenitor phenotype and function.

Recruitment and proliferation of CD4+ T cells in synovium following adoptive transfer of adjuvant-induced arthritis.

Adjuvant-induced arthritis can be transferred to naive Dark Agouti (DA) strain (DA.CD45.1) rats by thoracic duct (TD) lymphocytes.