Reports from the world of equine research.
The battle against sarcoids is forging ahead with the news that researchers in Scotland have succeeded in killing equine sarcoid cells using a technique known as gene silencing. The researchers are now hoping to obtain funding for clinical trials using the new technique, which could result in a more effective, non-toxic treatment for sarcoids.
Sarcoids are skin tumours caused by infection with the Bovine Papillomavirus (BPV). They are the most common type of tumour found in horses. It is estimated that 6-7% of horses in the UK are affected. Currently there is no universally effective treatment for sarcoids and if treatment fails the sarcoids will often come back worse than they were in the first place. Although the disease is rarely life threatening, many horses with sarcoids are euthanased because the condition is untreatable or because the horse is unsellable.
But research funded by The Horse Trust offers a potential ray of hope for owners of horses affected by sarcoids. The work was published in the journal Virus Research earlier this year.
The research, which was led by Professor Lubna Nasir of the University of Glasgow, found that by inhibiting the activity of a particular viral protein within sarcoid cells, the amount of viral DNA in the cells reduced. This led to a reduction in the growth of the sarcoid cells and caused the cell to die by “Programmed cell-death” (PCD). The researchers believe that PCD occurs because the sarcoid cells become reliant on the virus.
"This could potentially be a major breakthrough in the treatment of sarcoids," said Professor Lubna Nasir. "We are now seeking funding to use this technique in clinical trials on horses that have sarcoids."
The research team inhibited the activity of a viral protein called E2, which is needed by BPV to replicate. They used a novel approach termed 'gene silencing' to suppress the activity of the gene that codes the E2 protein. The research was carried out in the laboratory on fibroblast cells, which had been cultured from sarcoid tissue removed from animals during surgery.
As this research was carried out in vitro, the researchers will now need to see if they can replicate the results in vivo, by developing a way of targeting the sarcoid cells in horses.
"One of the challenges with gene silencing is administering it within clinical setting - as you need to get molecules into every cell. As sarcoids are on the surface of a horse, we think administration should be relatively easy - potentially by injecting or applying a cream to the sarcoid," said Professor Nasir. "If we are able to successfully develop this technique it would be a non-toxic and easy to administer treatment for horses affected by this distressing condition."
Nasir's research could also have an impact on the treatment of lesions in cattle, which are also caused by BPV. It may also help with the treatment of Human Papillomavirus (HPV) infections in humans. HPV, which is similar to BPV, can lead to various cancers in humans including cervical and vaginal cancer.
For more details see:
Gobeil PA, Yuan Z, Gault EA, Morgan IM, Campo MS, Nasir L. Small interfering RNA targeting bovine papillomavirus type 1 E2 induces apoptosis in equine sarcoid transformed fibroblasts. Virus Res. 2009 145(1):162-165.
There is more information on sarcoids, their prevalence, appearance, diagnosis and treatment options on the University of Liverpool website: http://www.liv.ac.uk/sarcoids/index.htm
For more information on the work of the Horse Trust see:
News release edited by Mark Andrews. Published online 18.01.10
© Copyright Equine Science Update 2010
Sarcoid treatment breakthrough
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