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| CSIRO | SOLVE | Issue 6 Feb 06 | |
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ARTICLE
HEALTH TECHNOLOGIES:
Joint Effort Proves Promising By Whitney MacDonald
A pairing of cellular and polymer technologies could soon be used to repair the damaged knees of thousands of Australians. A characteristically Australian trait is the love of sport. Unfortunately, this love affair with activity often comes at a painful price, with more than a million sports-related injuries occurring each year, 12 per cent of them involving the knee joint. Current knee injury treatment options can provide some relief, but they have limitations.
One component of the knee joint particularly prone to damage is the cartilage, comprised of the shock-absorbing menisci, that sit in between the femur and tibia, and the articular cartilage, a thick covering at the end of the knee bones that minimises damage to them by providing a near frictionless surface on which the bones can slide. Severe damage to the cartilage might require a total knee replacement. The short life expectancy of the replaced joint – generally 10 to 15 years – makes it an unfavourable option for a young person likely to need multiple replacements in the course of their life. Alternatively, a patient may receive autologous chondrocyte implantation (ACI); that is, injection of healthy cartilage-forming cells, taken from an undamaged site in the patient’s body, which have been expanded before being injected into the damaged site. However, this treatment does not allow any mechanical support, so that the patient must spend several weeks on crutches. A better option is now under development. A joint research team, comprised of scientists from CSIRO Molecular and Health Technologies, the Industrial and Technology Research Institute of Taiwan (ITRI), and PolyNovo Biomaterials Pty Ltd – a subsidiary company of Xceed Biotechnologies Ltd – is developing a superior tissue-engineering technology to treat damaged cartilage. By drawing on both the biological and chemical expertise within the team, researchers have devised a two-pronged approach to treating an injured knee. The first component uses proprietary cellular techniques to grow a large number of healthy chondrocytes for ACI in a short time, about 10 days. By using a combination of growth supplements, bead matrices and optimised cell densities in a bioreactor, culturing conditions promote rapid growth of chondrocytes, while still maintaining their cartilage-specific cell type – an aspect that has proven difficult with current ACI methods. To complement the cellular treatment of damaged cartilage, the second prong of the technology incorporates the patented polymer system NovoSorb™, a novel biodegradable polymer designed for use in human medical devices. Specially optimised grades are being tailored to act as synthetic scaffolding to offer support and stability to a recovering knee joint. The uncured polymer is mixed with expanded healthy cells from a person’s body, and then injected into the site of damaged cartilage using arthroscopy (keyhole surgery). Dr Charles Lindall, who leads the commercialisation of this project at CSIRO, says the strength of the product comes from combining the biological and chemical technologies to offer patients and surgeons a more comprehensive treatment option. “NovoSorb™ provides the initial repair and support, while the cells slowly start to regenerate and become functional tissue,” he says. “The polymer is non-toxic to the cells and porous, allowing the necessary exchange of nutrients for cell viability. “Once the cells have reached a functional level, the polymer slowly degrades, leaving the newly generated cartilage to resume its normal role of stabilising the knee joint.” The new technology will speed the treatment procedure in both the surgery and the recovery phases. “The proprietary cell culturing technology enables us to reduce the time needed to expand the healthy chondrocytes from many weeks to a mere 10 days, allowing the injured patient to begin treatment sooner,” Dr Lindall says. The collaboration’s goal is to reduce the surgery time from 90 minutes to about 30 minutes with the arthroscopic delivery of cells mixed with NovoSorb™ polymer. “We are aiming for a speedier recovery, too. Because NovoSorb™ should provide almost immediate stability in the joint, we anticipate the patient will walk out of the hospital the next day without crutches.” While the polymer-cellular technology has only been developed in the past year and a half, the results in animal models look promising, with clinical trials expected to be carried out over the next three years. This time will also serve as a patent-finalising and capital-raising period, before a market launch. In addition, the team will ultimately be considering forming a spin-off company and/or a partnership with a larger company. “Although our initial market is patients with knee injuries, this technology has applications for other injured joints as well as degenerative damage to tissue,” he says. “The current medical trend is about teaching the body how to heal itself, rather than having totally synthetic materials in the body and never regenerating its own natural tissue.” With a global market of more than $2 billion for cartilage repair, this is one trend that is not likely to go out of style. APPLICATION Treatment options are limited for the many thousands of knee injuries sustained each year For further information contact: |
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However, in a scientific joint venture, local researchers are pairing cellular and polymer technologies to create future treatment options.
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