Identification and Re-consent of Existing Cord Blood Donors for Creation of Induced Pluripotent Stem Cell Lines for Potential Clinical Applications.

We aim to create a bank of clinical grade cord blood-derived induced pluripotent stem cell lines in order to facilitate clinical research leading to the development of new cellular therapies. Here we present a clear pathway toward the creation of such a resource, within a strong quality framework, and with the appropriate regulatory, government and ethics approvals, along with a dynamic follow-up and re-consent process of cord blood donors from the public BMDI Cord Blood Bank. Interrogation of the cord blood bank inventory and next generation sequencing was used to identify and confirm 18 donors with suitable HLA homozygous haplotypes.

In vivo tissue engineering of an adipose tissue flap using fat grafts and Adipogel.

For decades, plastic surgeons have spent considerable effort exploring anatomical regions for free flap design. More recently, tissue-engineering approaches have been utilised in an attempt to grow transplantable tissue flaps in vivo. The aim of this study was to engineer a fat flap with a vascular pedicle by combining autologous fat grafts and a novel acellular hydrogel (Adipogel) in an established tissue-engineering model comprising a chamber and blood vessel loop.

Fate of Free Fat Grafts with or without Adipogenic Adjuncts to Enhance Graft Outcomes.

Background: Free fat grafting is popular, but it is still unclear how it works. Although focusing on graft survival seems an obvious direction for improving clinical results, the authors' research suggests that long-term volume retention is in part attributable to new fat regeneration. Measures to facilitate adipogenesis may therefore be equally important.

Biocompatible Porous Polyester-Ether Hydrogel Scaffolds with Cross-Linker Mediated Biodegradation and Mechanical Properties for Tissue Augmentation.

Porous polyester-ether hydrogel scaffolds (PEHs) were fabricated using acid chloride/alcohol chemistry and a salt templating approach. The PEHs were produced from readily available and cheap commercial reagents via the reaction of hydroxyl terminated poly(ethylene glycol) (PEG) derivatives with sebacoyl, succinyl, or trimesoyl chloride to afford ester cross-links between the PEG chains. Through variation of the acid chloride cross-linkers used in the synthesis and the incorporation of a hydrophobic modifier (poly(caprolactone) (PCL)), it was possible to tune the degradation rates and mechanical properties of the resulting hydrogels.

A Streamlined Method for the Preparation of Growth Factor-enriched Thermosensitive Hydrogels from Soft Tissue.

Hydrogels are an ideal medium for the expansion of cells in three dimensions. The ability to induce cell expansion and differentiation in a controlled manner is a key goal in tissue engineering. Here we describe a detailed method for producing hydrogels from soft tissues with an emphasis on adipose tissue.

Extracellular matrix fibronectin mediates an endothelial cell response to shear stress via the heparin-binding, matricryptic RWRPK sequence of FNIII1H.

Endothelial cells (EC) respond to mechanical forces such as shear stress in a variety of ways, one of which is cytoskeletal realignment in the direction of flow. Our earlier studies implicated the extracellular matrix protein fibronectin in mechanosensory signaling to ECs in intact arterioles, via a signaling pathway dependent on the heparin-binding region of the first type III repeat of fibrillar fibronectin (FNIII1H). Here we test the hypothesis that FNIII1H is required for EC stress fiber realignment under flow.

An adipogenic gel for surgical reconstruction of the subcutaneous fat layer in a rat model.

'Off-the-shelf' tissue-engineered skin alternatives for epidermal and dermal skin layers are available; however, no such alternative for the subdermal fat layer exists. Without this well-vascularized layer, skin graft take is variable and grafts may have reduced mobility, contracture and contour defects. In this study a novel adipose-derived acellular matrix (Adipogel) was investigated for its properties to generate subdermal fat in a rat model.

Dermal matrices and bioengineered skin substitutes: a critical review of current options.

Background: Over recent decades, scientists and surgeons have collaborated to develop various bioengineered and synthetic products as an alternative to skin grafts. Despite the numerous articles and reviews written about dermal skin substitutes, there is no general consensus.

Methods: This article reviews dermal skin scaffolds used in clinical applications and experimental settings.

Macrophage phenotype in response to implanted synthetic scaffolds: an immunohistochemical study in the rat.

Macrophages predominate among the cells that directly interact with biomaterials and are key orchestrators of host-biomaterial interactions. However, the macrophage response to synthetic scaffolds in particular has not been well studied. The aim of this study was therefore to characterise the macrophage response to several synthetic scaffolds in the rat using immunohistological techniques for a panel of markers of macrophage subclass or activation, including ED1 (CD68), ED2 (CD163), CD80, mannose receptor and inducible nitric oxide synthase (iNOS).

Biodegradable and biocompatible poly(ethylene glycol)-based hydrogel films for the regeneration of corneal endothelium.

Corneal endothelial cells (CECs) are responsible for maintaining the transparency of the human cornea. Loss of CECs results in blindness, requiring corneal transplantation. In this study, fabrication of biocompatible and biodegradable poly(ethylene glycol) (PEG)-based hydrogel films (PHFs) for the regeneration and transplantation of CECs is described.

Acrylic acid surface-modified contact lens for the culture of limbal stem cells.

Surface treatment to a biomaterial surface has been shown to modify and help cell growth. Our aim was to determine the best surface-modified system for the treatment of limbal stem cell deficiency (LSCD), which would facilitate expansion of autologous limbal epithelial cells, while maintaining cultivated epithelial cells in a less differentiated state. Commercially available contact lenses (CLs) were variously surface modified by plasma polymerization with ratios of acrylic acid to octadiene tested at 100% acrylic acid, 50:50% acrylic acid:octadiene, and 100% octadiene to produce high-, mid-, and no-acid.

Plasma polymer-coated contact lenses for the culture and transfer of corneal epithelial cells in the treatment of limbal stem cell deficiency.

Extensive damage to the limbal region of the cornea leads to a severe form of corneal blindness termed as limbal stem cell deficiency (LSCD). Whereas most cases of corneal opacity can be treated with full thickness corneal transplants, LSCD requires stem cell transplantation for successful ocular surface reconstruction. Current treatments for LSCD using limbal stem cell transplantation involve the use of murine NIH 3T3 cells and human amniotic membranes as culture substrates, which pose the threat of transmission of animal-derived pathogens and donor tissue-derived cryptic infections.

Macrophages play a key role in angiogenesis and adipogenesis in a mouse tissue engineering model.

We have previously described a mouse adipose tissue engineering model using a silicon chamber enclosing the superficial epigastric pedicle in a Matrigel based environment. We have shown that when Zymosan, a sterile inflammatory agent, is added to the chamber, angiogenesis and adipogenesis are significantly improved. As Zymosan interacts with toll-like receptors on macrophages, the role of macrophages in new tissue development in the tissue engineering chamber was assessed.

Hypoxic conditioning enhances the angiogenic paracrine activity of human adipose-derived stem cells.

Human adipose-derived stem cells (ASCs) secrete cytokines and growth factors that can be harnessed in a paracrine fashion for promotion of angiogenesis, cell survival, and activation of endogenous stem cells. We recently showed that hypoxia is a powerful stimulus for an angiogenic activity from ASCs in vitro and here we investigate the biological significance of this paracrine activity in an in vivo angiogenesis model. A single in vitro exposure of ASCs to severe hypoxia (<0.

An adipoinductive role of inflammation in adipose tissue engineering: key factors in the early development of engineered soft tissues.

Tissue engineering and cell implantation therapies are gaining popularity because of their potential to repair and regenerate tissues and organs. To investigate the role of inflammatory cytokines in new tissue development in engineered tissues, we have characterized the nature and timing of cell populations forming new adipose tissue in a mouse tissue engineering chamber (TEC) and characterized the gene and protein expression of cytokines in the newly developing tissues. EGFP-labeled bone marrow transplant mice and MacGreen mice were implanted with TEC for periods ranging from 0.

Preparation of an adipogenic hydrogel from subcutaneous adipose tissue.

The ability to generate controlled amounts of adipose tissue would greatly ease the burden on hospitals for reconstructive surgery. We have previously shown that a tissue engineering chamber containing a vascular pedicle was capable of forming new fat; however, further refinements are required to enhance fat formation. The development and maintenance of engineered adipose tissue requires a suitable source of growth factors and a suitable scaffold.

Revascularization and tissue regeneration of an empty root canal space is enhanced by a direct blood supply and stem cells.

Background: Regenerative endodontics is an innovative treatment concept aiming to regenerate pulp, dentin and root structures. In the diseased or necrotic tooth, the limitation in vascular supply renders successful tissue regeneration/generation in a whole tooth challenging. The aim of this study is to evaluate the ability of vascularized tissue to develop within a pulpless tooth using tissue engineering techniques.

Long-term stability of adipose tissue generated from a vascularized pedicled fat flap inside a chamber.

Background: Numerous studies demonstrate the generation and short-term survival of adipose tissue; however, long-term persistence remains elusive. This study evaluates long-term survival and transferability of de novo adipose constructs based on a ligated vascular pedicle and tissue engineering chamber combination.

Methods: Defined adipose tissue flaps were implanted into rats in either intact or perforated domed chambers.

Intrinsics and dynamics of fat grafts: an in vitro study.

Background: Despite a revived interest in fat grafting procedures, clinicians still fail to demonstrate clearly the in vivo behavior of fat grafts as a dynamic tissue substitute. However, the basic principles in cellular biology teach us that cells can survive and develop, provided that a structural matrix exists that directs their behavior. The purpose of this in vitro study was to analyze that behavior of crude fat grafts, cultured on a three-dimensional laminin-rich matrix.

Epoxy-amine synthesised hydrogel scaffolds for soft-tissue engineering.

Highly porous and biodegradable hydrogels based on poly(ethylene glycol) (PEG) and cystamine (Cys) were fabricated using epoxy-amine chemistry and investigated as scaffolds for soft-tissue engineering. Whereas the application of fused-salt templates provided a comprehensive interconnecting pore morphology, the incorporation of a specially designed poly(epsilon-caprolactone) (PCL) cross-linker provided enhanced mechanical function without adversely effecting the scaffolds positive biological interactions. The addition of only 1.

Vascularized tissue engineering mouse chamber model supports thymopoiesis of ectopic thymus tissue grafts.

We have previously established a chamber model of tissue engineering that promotes de novo angiogenesis and vascularization of engrafted cells and tissues when combined with an extracellular matrix. Here we demonstrate that the mouse chamber (MC) model can sustain ectopic grafts of murine fetal thymus lobes and, to a limited degree, human pediatric thymus tissue, resulting in de novo T-cell production. Silicone chambers containing Matrigel((R)) and thymus tissues were placed around exposed epigastric vessels and the ends sealed with bone wax, before implantation into the inguinal fat pad of athymic Balb/c(nu/nu) (nude) mice.

Role of NADPH oxidase in tissue growth in a tissue engineering chamber in rats.

Previously we described a subcutaneous arteriovenous loop (AVL)-based tissue engineering chamber system, which contains an intrinsic circulation circuit created by joining the proximal ends of the femoral artery and vein with a venous graft. We showed that nicotinamide adenine dinucleotide phosphate (NADPH) oxidase was involved in mediating neovascularization inside the chamber. However, the role of NADPH oxidase in tissue formation in the chamber is unknown.

Monocyte chemoattractant protein-1 and nitric oxide promote adipogenesis in a model that mimics obesity.

Objective: An increasing body of evidence is emerging linking adipogenesis and inflammation. Obesity, alone or as a part of the metabolic syndrome, is characterized by a state of chronic low-level inflammation as revealed by raised plasma levels of inflammatory cytokines and acute-phase proteins. If inflammation can, in turn, increase adipose tissue growth, this may be the basis for a positive feedback loop in obesity.

Adipose differentiation of bone marrow-derived mesenchymal stem cells using Pluronic F-127 hydrogel in vitro.

Due to increasing clinical demand for adipose tissue, a suitable scaffold for engineering adipose tissue constructs is needed. In this study, we have developed a three-dimensional (3-D) culture system using bone marrow-derived mesenchymal stem cells (BM-MSC) and a Pluronic F-127 hydrogel scaffold as a step towards the in vitro tissue engineering of fat. BM-MSC were dispersed into a Pluronic F-127 hydrogel with or without type I collagen added.