TRR Current Projects

Improved Safety, Speed of Treatment and Treatment Outcome of Patients with Significant Burns

Funding

$328,000 in 2003-2004 from Red Cross Society Bali Relief Appeal; $164,000 in 2003-2004 from QUT Links with Industry Scheme.

Program Members Involved

Dr Zee Upton, Dr Damien Harkin, Assoc Prof David Leavesley, Ms Rebecca Dawson, Ms Carolyn Hyde, Mr Brett Hollier

Collaborators

Dr Robyn Minchinton, Dr. Peter Choong and Mr Peter Gilles (Queensland Skin Bank, Australian Red Cross Blood Service); Dr. Michael Rudd (Royal Brisbane Hospital)

Summary of Project

QUT and Australian Red Cross Blood Service scientists have jointly undertaken preliminary studies suggesting that the use of novel growth factor/extracellular matrix proteins complexes, will improve the safety and importantly, the speed with which skin cells can be cultured for patient grafts. We now wish to extend these studies to enable translation of this data to the clinical setting and moreover, further develop the technology so that the patient's cells plus the complexes can be applied as a spray +/- a dermal scaffold. Earlier skin replacement is urgently needed to reduce patient physical and psychological trauma, scarring and the present requirement for expensive temporary skin replacements.

Functional Characterization of a Novel IGF-Binding Protein Complex in the Proliferation and Migration of Cells

Funding

$142,500 over 2002-2003 from Queensland Cancer Fund.

Program Members Involved

Dr Zee Upton, Assoc Prof David Leavesley, Prof Sean McElwain, Mr Chris Towne, Mr Anthony Noble

Summary of Project

This project seeks to understand how IGFs, factors that stimulate the growth of cells, and their interactions with vitronectin, a protein that is abundant in the environment surrounding cells and is critical for cell adhesion, impact on the proliferation and migration of cells. Our studies in cell lines have revealed that these complexes significantly enhance cell migration - a process critical for the spread of tumours, and also for wound repair processes. Furthermore, we have established that this increase in cell migration involves co-activation of both the IGF and vitronectin-binding cell surface receptors on the cells, information that we have protected through filing a patent application. Our investigations are now focussed on determining whether the complexes modify other cellular processes including apoptosis and angiogenesis. In addition, the data generated is being used to develop mathematical models to describe the cell invasion/migration processes, knowledge that is required to effectively design therapeutics to inhibit the spread of cancer, and to enhance wound repair.

Development of a Novel Therapeutic for Accelerating Repair of Diabetic Ulcers

Funding

$39,844 in 2003 from Diabetes Australia Research Trust.

Program Members Involved

Dr Zee Upton, Dr Damien Harkin, Assoc Prof David Leavesley, Mr Anthony Noble, Ms Rebecca Dawson

Collaborators

Prof John Prins (Princess Alexandra Hospital)

Summary of Project

The Investigators have discovered novel links between insulin-like growth factors (IGFs), IGF-binding proteins and vitronectin (VN) and have protected these growth factor complexes through an international patent application. Moreover, our recent functional studies in skin and corneal keratinocytes demonstrating enhanced cell proliferation and migration in the presence of these complexes have led us hypothesise that these complexes will enhance re-epithelialization and cell growth in wounds exhibiting delayed repair. This is especially relevant in patients with diabetes as as the wound healing process is generally retarded. Furthermore, there is a lack of IGF expression in diabetic skin and diabetic foot ulcer tissue, hence the absence of secreted IGF is thought to contribute to the delayed wound healing response. It is for these reasons the investigators are examining the use of IGF:VN complexes in diabetic ulcers. Specifically, the investigators aim to develop an IGF:VN complex specifically formulated to optimally concentrate IGFs, and other growth promoting agents, for the purpose of accelerating proliferation and migration of skin keratinocytes derived from diabetic patients.

Development of Novel Therapies for Repairing the Surface of the Eye

Funding

$9,500 in 2003 from Ophthalmic Research Institute of Australia; $8,000 in 2003 from Queensland University of Technology Small Grants Scheme; $15,000 in 2003 from Royal Brisbane Hospital Research Foundation

Program Members Involved

Dr Damien Harkin, Dr Zee Upton, Mr Zeke Barnard, Mr Brett Hollier, Ms Louise Ainscough

Collaborators

Dr Andrew Apel (Princess Alexandra and Royal Brisbane Hospitals)

Summary of Project

Our team of research scientists and ophthalmic surgeons is currently developing techniques to treat severe corneal injuries. More specifically, we are interested in the adult stem cells which maintain the smooth transparent characteristics of the ocular surface. When these stem cells are lost during injury the surrounding conjunctiva begins to encroach upon the cornea thus producing an abnormal and dysfunctional ocular surface. In order to treat this condition our team has established a method for cultivating and grafting corneal stem cells derived from a patient's non-injured eye. At this stage out technique is based on those successfully employed by Michele De Luca's laboratory in Rome and Ivan Schwab's team at UC Davis. Five patient's have received grafts thus far and our preliminary assessments of the outcomes are positive. Nevertheless, we aim to improve our technique further by researching a number of key areas, namely; markers for identifying corneal stem cells, manipulation of culture conditions to optimise stem cell numbers, and development of improved carrier materials for the grafting the cultured cells. Moreover, we are interested in the possibility of producing corneal tissue in the laboratory from adult stem cells obtained from other tissue.

Elucidating the Role of Silicones in the Treatment of Burn Scars

Funding

$81,876 from ARC Linkage and Royal Brisbane Hospital in 2001-2003

Program Members Involved

Prof Graeme George, Dr Thor Bostrom, Mr W Sanchez.

Summary of Project

Silicone gel sheets have been clinically proven to rehabilitate hypertrophic scars, and this treatment often works when other conventional treatments have failed. Mechanisms proposed include increased skin temperature to increase the rate of collagenase reactions; control of skin hydration; a direct chemical reaction of components migrating from the gel or their mechanical effect on the scar. In this study, the nature and migration of the low molecular weight species from these silicone gels and their possible effect on hypertrophic scars is being investigated.

Tissue-engineered Bone Regeneration from Osteoblast Progenitor Cells

Funding

$222,554 over 2002-2005 from NHMRC Peter Doherty Fellowship awarded to Dr Yin Xiao

Program Members Involved

Dr Yin Xiao, Assoc Prof David Leavesley, Prof Adrian Herington, Prof Ross Crawford

Summary of Project

Bone defects, which result from tumours, diseases and infections, trauma, biochemical disorders, and abnormal skeletal development, pose a significant health problem. Currently, three different grafting materials are used: autografts, allografts, and synthetic materials. However, the relative shortage of autograft tissue and the potential for disease transmission and adverse host immune reaction with allografts have increased the need for synthetic bone substitutes and have inspired a search for improved methods for repairing skeletal defects.

Tissue engineering is a new concept involving three-dimensional autologous tissue growth by culturing cells on synthetic polymer scaffolds before implantation into patients. This project will use human bone marrow stromal cells obtained from bone marrow aspirates and alveolar bone derived osteoblasts separated from human alveolar bone biopsies. These cells will be incorporated into a three-dimensional biodegradable PGL scaffold to produce an engineered bone tissue. The "engineered" tissues will be analysed for their matrix components via immunohistochemistry, Western Blot for protein deposition and localization, and via in situ hybridization and real time PCR for the matrix gene expression and quantitation. The engineered bone tissue will then be delivered into both bone defect sites and subcutaneous areas in immunodeficienct mice (SCID) and assessed histologically for their ability to induce bone regeneration. Specific features to be assessed at this stage will include rate of vascularization of the transplanted engineered tissue, analysis of the fate of the introduced cells, bone matrix formation, and histological examination for bone tissue formation.

Novel Load Bearing Polymeric Bone Substitute for Orthopaedic Applications

Funding

$12,000 in 2003 from Queensland University of Technology Small Grants Scheme; $10,000 in 2003 from the Queensland Orthopaedic Research Trust

Program Members Involved

Prof Graeme George, Prof Ross Crawford, Prof Mark Pearcy, Dr Cameron Lutton, Assoc Prof David Leavesley

Summary of Project

At times the amount of bone lost due to disease and injury is too great for regeneration and proper healing. When this occurs, a bone graft is used to facilitate healing. In the U.S., in 1998, over 500,000 bone graft operations were performed and 170,000 fractures failed to heal properly and required some form of bone graft. The deficiencies of these implants in load bearing situations have been driving research for alternative graft options for over 30 years. An optimal implant needs to possess the following features: mechanical properties that closely match those of bone, an interconnected porous network (allowing for cell and blood vessel ingrowth), and the capacity to induce a positive interaction with the surrounding tissue (bioactivity). Furthermore, as the bone of our body is constantly remodelling, an optimal implant would be absorbed by the body over time and replaced by native bone. To date, no graft alternative has been able to combine all of these aspects.

By investigating a series of nanocomposite scaffolds this research aims to produce novel composite scaffolds with designed macrostructures having tailored biodegradability and sufficient mechanical and biological properties to function as a bone replacement implant in a load bearing situation. The scaffolds will be based on a design consisting of two phases, a slowly degrading polymer/nanocomposite reinforcing phase that will sustain a load throughout the implants lifetime, and a more rapidly adsorbed polymer phase to create porosity and release osteogenic factors to encourage bone ingrowth.

Optimum Biomechanical and Bioelectric Environment for Bone Cell Growth

Funding

$10,000 in 2003 from Queensland Orthopaedic Research Trust

Program Members Involved

Prof Mark Pearcy, Assoc Prof David Leavesley, Prof Ross Crawford, Mr Gwynne Hanney

Summary of Project

This project will evaluate the effects of mechanical strain and indirect electrical stimulation upon bone forming osteoblastic cells. The key objective is to determine the effect of mechanical strain and indirect electrical stimulation on immature bone cells to influence proliferation, differentiation and other key cellular processes involved in the production of bone. Knowledge of an optimum environment to influence the rate of proliferation and differentiation of a cell will be a valuable tool for a number of therapeutic applications such as osseointegration of implanted biomaterials used within arthroplasty and seeding a cellular scaffold for in vivo implantation.

Biomaterial-Cell Interactions Mediated by Adsorbed Proteins

Funding

$10,000 in 2003 from Queensland Orthopaedic Research Trust

Program Members Involved

Prof Mark Pearcy, Assoc Prof David Leavesley, Prof Ross Crawford, Dr Graeme Pettet, Dr Zee Upton, Mr Cameron Wilson

Summary of Project

The integration of orthopaedic implants in bone requires tissue regeneration at the implant surface. This in turn requires appropriate stimulation of the surrounding bone-forming cells. Cell responses are largely governed by the proteins adsorbed to the foreign surface and it is this protein mediation of interactions between cells and surfaces that is the major focus of this project. It aims to determine mechanisms by which particular surface characteristics affect the "selection", quantity and biological activity of proteins that adsorb from blood. The work is also investigating the effectiveness of a novel growth factor coating in stimulating cell growth and bone formation.

Novel Polymeric Scaffolds for use in Craniofacial Repair

Funding

$10,000 in 2003 from QUT Small Grants Scheme; $6,100 from the Innovation Access Program International Science Technology Programme (IAP-IST) for study leave to consolidate collaboration with Professor Schué at the University of Montpellier, France.

Program Members Involved

Dr Edeline Wentrup-Byrne, Prof Graeme George, Prof Sean McElwain, Assoc Prof David Leavesley, Mr John Colwell, Ms Karina George, Mr Cameron Hall, Ms Shuko Suzuki.

Collaborators

Prof Francois Schué (University of Montpellier), Dr Lisbeth Grøndahl (University of Queensland)

Summary of Project

The development of novel polymeric scaffolds that are both bioactive and bioabsorable is the first step in custom-designing tissue scaffolds for specific tissue replacement/regeneration applications. It is now widely accepted that ideally a material must interact bioactively with the tissue being replaced rather than acting only as a replacement. Depending on the particular function of the scaffold eg guided bone, cartilage, or skin regeneration, one challenge is to ensure that the bulk properties of the material especially the physio-chemical and mechanical properties be maintained during the bioabsorption process. This may vary from a few weeks to six months depending on the particular application. One of the major challenges in synthesising suitable scaffolds is being able to design the chemical composition of the polymer so that both the rate of absorption and mechanical properties can be controlled. At the same time, both the material and its degradation products must be both biocompatible and non-toxic. One approach is to synthesise block copolymers which combine different properties [PLA-PGA, PCL-PLA, various PHBV combinations. Another is to modify the mechanical or other properties of a known biocompatible system through co-polymerisation. Judicious choice of monomers, catalyst, degree of cross-linking, strength and molecular weight under controlled synthesis conditions should lead to a variety of commercially viable materials.

Currently we are focusing on synthesising two different scaffold systems: the first a completely bioabsorable polycaprolactone-based one designed for use in craniofacial applications and the second a partly bioabsorbable, modified polyHEMA-based polymer for use in cranial repair.

In a related project, we are examining highly porous PTFE membranes (Gore), currently used in facial reconstructive surgery. Our aim is to improve this biomaterial by creating a more bioactive surface through the introduction of ionic groups onto the surface. We have shown that the modification of microporous PTFE by incorporating phosphate groups as surface-active sites promotes bone hydroxyapatite growth. Currently we are studying the role of the surface changes on cell behaviour.