Hydrogel injections could ease lower back pain

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Intradiscal injection for back painChronic lower back pain could eventually be treated with hydrogel injections that restore the shock-absorbing properties of damaged intervertebral discs.

Researchers at Sheffield Hallam University have developed a unique hydrogel delivery system that contains stem cells and chemical factors that may combat degeneration and promote growth of damaged intervertebral discs.

Lower back pain affects approximately 80 per cent of the population at some point in their lives, incurring a cost of billions to the NHS and the wider economy through sick days.

Project leader Dr Christine Le Maitre said: ‘One of the main causes of low back pain is the close proximity of the nerve root to a lot of moveable structures — when you move, you bend, you flex; all of that is made possible because throughout your spine you have these intervertebral discs, which basically act as shock absorbers allowing all the stresses and strains to be dissipated though the spine.’

Around 40 per cent of cases of lower back pain are caused by degradation of the intervertebral discs, which are composed of a flexible matrix of proteoglycans and collagens, dispersed with maintenance cells.

Most of the current therapies are purely symptomatic or involve surgery, which does not address the underlying molecular causes of lower back pain.

For several years the researchers have been investigating the enzymes and growth factors that maintain the flexible matrix of the intervertebral discs. The team has also been working with adult bone-marrow stem cells, which may be able to take the place of the maintenance cells.

The challenge was to deliver stem cells, protein growth factors and inhibitors in a package that could potentially be injected directly into the intervertebral discs of patients.

The hydrogel solution that the group has devised essentially mimics the composition of the intervertebral disc and provides a favourable environment for the stem cells and protein factors to take effect — rather than just trying to introduce ‘naked’ stem cells and proteins.

‘That’s where a lot of projects are falling down; there are people looking at stem-cell use, but no one’s actually looking at inhibiting the causes of the disease in the first place.’

The group has recently shown that the stem cells and proteins can survive in the hydrogel and is currently investigating various hydrogel compositions.

The next step will be to test the hydrogel delivery package in a human tissue culture and then possibly animal models.