Proteomic study sheds light on neurodegeneration in grass sickness

Researchers at the Royal (Dick) School of Veterinary Studies and Roslin Institute have shed new light on the mechanisms which contribute to neurodegeneration in equine grass sickness, a multi-system neuropathy which kills an estimated 1-2% of horses in the UK.

The proteomic study, led by Prof Bruce McGorum, Head of the Equine Section at R(D)SVS and Dr Tom Wishart, from the Division of Neurobiology at Roslin Institute, identified key overlaps in the mechanisms of neurodegeneration in grass sickness and in human neurodegenerative conditions including Alzheimer’s disease and motor neuron disease. They identified significant alterations in the expression of 506 different proteins in autonomic ganglia from grass sickness horses compared with those from animals that had died from other causes. Interestingly, ganglia from grass sickness horses had increased levels of proteins that are commonly seen in the brains of people with Alzheimer’s disease, including amyloid protein.

Prof McGorum said ‘’While this study highlights important parallels in the pathways leading to neurodegeneration in grass sickness and human neurodegenerative diseases, the cause of this enigmatic disease remains unknown. Identifying the putative neurotoxin which triggers neurodegeneration in this devastating disease is our key objective.’’ Prof McGorum added that ‘We are hopeful that data from the study can be used to develop a non-invasive test to accurately diagnose grass sickness pre-mortem, since this is often challenging.

Horse with chronic grass sickness, showing marked weight loss and narrow stance. Photo provided by Bruce McGorum.
The study, funded by The Equine Grass Sickness Fund, is published in the journal Molecular and Cellular Proteomics.

Link to the full study: http://www.mcponline.org/content/early/recent