Saturday, June 6, 2009

tissue engineering

From building bones to fabricating flesh, tissue engineering is a growth area, and it was the focus of much attention at this year's British Association Festival of Science. Defined as the harnessing of living processes to achieve healing and repair of damaged and diseased tissues by Tim Hardingham, director of the UK Centre for Tissue Engineering, it is a field that requires collaborative research involving cell and molecular biologists, chemical engineers, materials scientists, and surgeons.

Tissue engineering has already demonstrated its worth when it comes to treating persistent leg ulcers, a problem particularly for the elderly. In these patients there is a breakdown in the normal biological signals, chemical messengers, and physical cues that promote the healing process.

Iain Kill of Brunel University described a biomaterial, "Permacol", that was developed over a period of 20 years at Dundee University. Now licensed by Tissue Science Laboratories for use in Europe and the U.S., it is derived from porcine skin, chemically treated to produce a collagenous, sterile, nonallergenic product, which resists biodegradation and can provide a permanent support for the ingrowth of new tissue and associated blood supply. It has been used internally to treat hernias and externally to treat ulcers and full thickness skin wounds. One exciting potential for Permacol is that it can be seeded with the patient's own cells, so that in the future it may be possible to repair cartilage or bone by seeding with chondrocytes or osteocytes.


Scientists at Strathclyde University reported the development of an artificial liver. Acute liver failure, commonly caused by paracetamol overdoses and hepatitis, is reversible--undamaged cells can repair the liver, but need help to recover. Unfortunately, at present "there's no treatment ... other than a transplant," explained Helen Grant. Grant's research team has found ways to attach liver cells in a single layer to films of plastic. They can be stored at -70°C until needed. To mimic liver function, patients' blood plasma is passed across the plates of cells, in a process akin to kidney dialysis. The Strathclyde researchers have tested the device on pigs, with encouraging results. U.S. biotechnology company Circe Biomedical has had similar success, she said, showing in an ongoing clinical trial of a similar device using pig liver cells that six out of 36 patients have completely recovered without the need for transplant. It is hoped that a similar technique using pancreatic cells could be used in the treatment of insulin-dependent diabetes.

So if you fancy moving into an area of research where laboratory findings are rapidly making their way into the clinical setting, where should you be heading? Two UK universities at the forefront of tissue engineering research are Manchester and Liverpool. They are partners in the UK Centre for Tissue Engineering, a 6-year, £10 million project funded jointly by the Biotechnology and Biological Sciences Research Council, the Engineering and Physical Sciences Research Council (EPSRC), and the Medical Research Council. Hardingham's group at Manchester provides expertise in cell preparation and preclinical testing, while Liverpool University's clinical engineering department, led by David Williams, has a track record in biomaterial matrices and biocompatibility testing. Manchester's School of Biological Sciences offers PhD studentships under the Wellcome Trust 4-year programme, while at Liverpool the clinical engineering department has research projects in the areas of biomaterials and biocompatibility, cardivascular bioengineering, and clinical engineering.

The Bioengineering Unit at Strathclyde University is an international centre of excellence for postgraduate education and research (it has received the top rating of 5 in the last three Research Assessment Exercises). There are undergraduate courses in bioengineering, and at postgraduate level it offers an MRes in biomedical engineering (EPSRC studentships are available) or MSc/PgDip/PgCert in bioengineering.

Tissue engineering is a growth area outside academia too, so there are job opportunities within emerging biotechnology companies. Renovo is a Manchester University spin out, founded by Mark Ferguson and Sharon O'Kane, that is researching prevention of scarring and wound healing. The company is happy to accept speculative CVs in a number of areas including pharmacology, molecular biology, and biochemistry. Another Manchester-based tissue engineering company, Intercytex was founded by Paul Kemp in1999. It has raised £7 million to take its research into regenerative technologies for end-stage renal disease and replacement of damaged tissues to clinical proof of concept. The company is currently advertising for research staff with cell biology, biochemistry, or immunology experience.

With an ageing population, Hardingham concludes, there is expanding demand in the UK and worldwide for tissue engineered products, which in turn will lead to a new, high-tech industry sector. Editor's Note: If this article has captured your imagination, look out for our November feature, which will be delving still deeper into the world of biomedical engineering!

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