Robust Angiogenesis and Arteriogenesis in the Skin of Diabetic Mice by Transient Delivery of Engineered VEGF and PDGF-BB Proteins in Fibrin Hydrogels.

Non-healing ulcers are a serious complication of diabetes mellitus and a major unmet medical need. A major cause for the lack of healing is the impairment of spontaneous vascularization in the skin, despite mostly normal blood flow in deeper large vessels. Therefore, pro-angiogenic treatments are needed to increase therapeutic perfusion by recruiting new arterial connections (therapeutic arteriogenesis).

Endothelial Lactate Controls Muscle Regeneration from Ischemia by Inducing M2-like Macrophage Polarization.

Endothelial cell (EC)-derived signals contribute to organ regeneration, but angiocrine metabolic communication is not described. We found that EC-specific loss of the glycolytic regulator pfkfb3 reduced ischemic hindlimb revascularization and impaired muscle regeneration. This was caused by the reduced ability of macrophages to adopt a proangiogenic and proregenerative M2-like phenotype.

Therapeutic vascularization in regenerative medicine.

Therapeutic angiogenesis, that is, the generation of new vessels by delivery of specific factors, is required both for rapid vascularization of tissue-engineered constructs and to treat ischemic conditions. Vascular endothelial growth factor (VEGF) is the master regulator of angiogenesis. However, uncontrolled expression can lead to aberrant vascular growth and vascular tumors (angiomas).

Mechanically Defined Microenvironment Promotes Stabilization of Microvasculature, Which Correlates with the Enrichment of a Novel Piezo-1 Population of Circulating CD11b /CD115 Monocytes.

Vascularization is a critical step in the restoration of cellular homeostasis. Several strategies including localized growth factor delivery, endothelial progenitor cells, genetically engineered cells, gene therapy, and prevascularized implants have been explored to promote revascularization. But, long-term stabilization of newly induced vessels remains a challenge.

Vascular endothelial growth factor biology for regenerative angiogenesis.

Despite major advances in medical, catheter-based or surgical treatment, cardiovascular diseases such as peripheral artery disease and coronary artery disease still cause significant morbidity and mortality. Furthermore, many patients do not qualify for catheter-based treatment or bypass surgery because of advanced disease or surgical risk. There is therefore an urgent need for novel treatment strategies.

Balanced single-vector co-delivery of VEGF/PDGF-BB improves functional collateralization in chronic cerebral ischemia.

The myoblast-mediated delivery of angiogenic genes represents a cell-based approach for targeted induction of therapeutic collateralization. Here, we tested the superiority of myoblast-mediated co-delivery of vascular endothelial growth factor-A (VEGF) together with platelet-derived growth factor-BB (PDGF-BB) on transpial collateralization of an indirect encephalomyosynangiosis (EMS) in a model of chronic cerebral ischemia. Mouse myoblasts expressing a reporter gene alone (empty vector), VEGF, PDGF-BB or VEGF and PDGF-BB through a single bi-cistronic vector (VIP) were implanted into the temporalis muscle of an EMS following permanent ipsilateral internal carotid artery occlusion in adult, male C57BL/6N mice.

Correlative Imaging of the Murine Hind Limb Vasculature and Muscle Tissue by MicroCT and Light Microscopy.

A detailed vascular visualization and adequate quantification is essential for the proper assessment of novel angiomodulating strategies. Here, we introduce an ex vivo micro-computed tomography (microCT)-based imaging approach for the 3D visualization of the entire vasculature down to the capillary level and rapid estimation of the vascular volume and vessel size distribution. After perfusion with μAngiofil®, a novel polymerizing contrast agent, low- and high-resolution scans (voxel side length: 2.

Long-term safety and stability of angiogenesis induced by balanced single-vector co-expression of PDGF-BB and VEGF164 in skeletal muscle.

Therapeutic angiogenesis by growth factor delivery is an attractive treatment strategy for ischemic diseases, yet clinical efficacy has been elusive. The angiogenic master regulator VEGF-A can induce aberrant angiogenesis if expressed above a threshold level. Since VEGF remains localized in the matrix around expressing cells, homogeneous dose distribution in target tissues is required, which is challenging.

Extracellular matrix and growth factor engineering for controlled angiogenesis in regenerative medicine.

Blood vessel growth plays a key role in regenerative medicine, both to restore blood supply to ischemic tissues and to ensure rapid vascularization of clinical-size tissue-engineered grafts. For example, vascular endothelial growth factor (VEGF) is the master regulator of physiological blood vessel growth and is one of the main molecular targets of therapeutic angiogenesis approaches. However, angiogenesis is a complex process and there is a need to develop rational therapeutic strategies based on a firm understanding of basic vascular biology principles, as evidenced by the disappointing results of initial clinical trials of angiogenic factor delivery.

Split for the cure: VEGF, PDGF-BB and intussusception in therapeutic angiogenesis.

Therapeutic angiogenesis is an attractive strategy to treat patients suffering from ischaemic conditions and vascular endothelial growth factor-A (VEGF) is the master regulator of blood vessel growth. However, VEGF can induce either normal or aberrant angiogenesis depending on its dose localized in the microenvironment around each producing cell in vivo and on the balanced stimulation of platelet-derived growth factor-BB (PDGF-BB) signalling, responsible for pericyte recruitment. At the doses required to induce therapeutic benefit, VEGF causes new vascular growth essentially without sprouting, but rather through the alternative process of intussusception, or vascular splitting.

Long-lasting fibrin matrices ensure stable and functional angiogenesis by highly tunable, sustained delivery of recombinant VEGF164.

Clinical trials of therapeutic angiogenesis by vascular endothelial growth factor (VEGF) gene delivery failed to show efficacy. Major challenges include the need to precisely control in vivo distribution of growth factor dose and duration of expression. Recombinant VEGF protein delivery could overcome these issues, but rapid in vivo clearance prevents the stabilization of induced angiogenesis.

Induction of aberrant vascular growth, but not of normal angiogenesis, by cell-based expression of different doses of human and mouse VEGF is species-dependent.

Therapeutic angiogenesis by vascular endothelial growth factor (VEGF) gene delivery is an attractive approach to treat ischemia. VEGF remains localized around each producing cell in vivo, and overexpression of mouse VEGF(164) (mVEGF(164)) induces normal or aberrant angiogenesis, depending strictly on its dose in the microenvironment in vivo. However, the dose-dependent effects of the clinically relevant factor, human VEGF(165) (hVEGF(165)), are unknown.

VEGF over-expression in skeletal muscle induces angiogenesis by intussusception rather than sprouting.

Therapeutic over-expression of vascular endothelial growth factor (VEGF) can be used to treat ischemic conditions. However, VEGF can induce either normal or aberrant angiogenesis depending on its dose in the microenvironment around each producing cell in vivo, which limits its clinical usefulness. The goal herein was to determine the cellular mechanisms by which physiologic and aberrant vessels are induced by over-expression of different VEGF doses in adult skeletal muscle.

Therapeutic angiogenesis due to balanced single-vector delivery of VEGF and PDGF-BB.

Therapeutic angiogenesis by delivery of vascular growth factors is an attractive strategy for treating debilitating occlusive vascular diseases, yet clinical trials have thus far failed to show efficacy. As a result, limb amputation remains a common outcome for muscle ischemia due to severe atherosclerotic disease, with an overall incidence of 100 per million people in the United States per year. A challenge has been that the angiogenic master regulator vascular endothelial growth factor (VEGF) induces dysfunctional vessels, if expressed outside of a narrow dosage window.

Taming of the wild vessel: promoting vessel stabilization for safe therapeutic angiogenesis.

VEGF (vascular endothelial growth factor) is the master regulator of blood vessel growth. However, it displayed substantial limitations when delivered as a single gene to restore blood flow in ischaemic conditions. Indeed, uncontrolled VEGF expression can easily induce aberrant vascular structures, and short-term expression leads to unstable vessels.

To sprout or to split? VEGF, Notch and vascular morphogenesis.

Therapeutic angiogenesis is an attractive strategy to treat patients suffering from peripheral or coronary artery disease. VEGF (vascular endothelial growth factor-A) is the fundamental factor controlling vascular growth in both development and postnatal life. The interplay between the VEGF and Notch signalling pathway has been recently found to regulate the morphogenic events leading to the growth of new vessels by sprouting.

FACS-purified myoblasts producing controlled VEGF levels induce safe and stable angiogenesis in chronic hind limb ischemia.

We recently developed a method to control the in vivo distribution of vascular endothelial growth factor (VEGF) by high throughput Fluorescence-Activated Cell Sorting (FACS) purification of transduced progenitors such that they homogeneously express specific VEGF levels. Here we investigated the long-term safety of this method in chronic hind limb ischemia in nude rats. Primary myoblasts were transduced to co-express rat VEGF-A(164) (rVEGF) and truncated ratCD8a, the latter serving as a FACS-quantifiable surface marker.

High-throughput flow cytometry purification of transduced progenitors expressing defined levels of vascular endothelial growth factor induces controlled angiogenesis in vivo.

Delivery of therapeutic genes by genetically modified progenitors is a powerful tool for regenerative medicine. However, many proteins remain localized within or around the expressing cell, and heterogeneous expression levels can lead to reduced efficacy or increased toxicity. For example, the matrix-binding vascular endothelial growth factor (VEGF) can induce normal, stable, and functional angiogenesis or aberrant angioma growth depending on its level of expression in the microenvironment around each producing cell, and not on its total dose.

In vitro and in vivo validation of human and goat chondrocyte labeling by green fluorescent protein lentivirus transduction.

We investigated whether human articular chondrocytes can be labeled efficiently and for long-term with a green fluorescent protein (GFP) lentivirus and whether the viral transduction would influence cell proliferation and tissue-forming capacity. The method was then applied to track goat articular chondrocytes after autologous implantation in cartilage defects. Expression of GFP in transduced chondrocytes was detected cytofluorimetrically and immunohistochemically.

Atypical GPI-anchored T-cadherin stimulates angiogenesis in vitro and in vivo.

Objective: T-cadherin (T-cad) is an atypical GPI-anchored member of the cadherin superfamily. In vascular tissue, T-cad expression is increased during atherosclerosis, restenosis, and tumor neovascularization. In vitro, overexpression and/or homophilic ligation of T-cad on endothelial cells (ECs) facilitates migration, proliferation, and survival.

Haplotype sharing suggests that a genomic segment containing six genes accounts for the pulmonary adenoma susceptibility 1 (Pas1) locus activity in mice.

The pulmonary adenoma susceptibility 1 (Pas1) locus affects inherited predisposition and resistance to chemically induced lung tumorigenesis in mice. The A/J and C57BL/6J mouse strains carry the susceptibility and resistance allele, respectively. We identified and genotyped 65 polymorphisms in the Pas1 locus region in 29 mouse inbred strains, and delimited the Pas1 locus to a minimal region of 468 kb containing six genes.