CASE STUDY:

Improving the measurement of systemic ammonia for better chronic disease management

Research Team: Prof Tony Killard

Ammonia is a toxic byproduct of protein metabolism, but is normally handled safely by the liver, where it is converted to urea. However, several conditions reduce the body's capacity to remove ammonia. These include liver disease, as well as rare metabolic conditions called Urea Cycle Disorders (UCD). This can lead to large increases in systemic ammonia, which causes serious neurological impairment, which is often permanent and fatal.

Ammonia must be measured in such conditions. However, presently, it can only be measured effectively in blood in the hospital. Research at UWE has been focused on the development of simple and sensitive electrochemical sensors that can improve the measurement of ammonia in both blood and breath. The sensors are fabricated from a conducting polymer nanomaterial that is responsive to ammonia. Working with diagnostic company, BreathDX and Prof. Hamilton-Shield, a paediatric metabolic specialist at Bristol Children's Hospital, these sensors have been applied to the measurement of breath ammonia in UCD patients, both in the hospital and at home. It is hoped that patients can simply and conveniently measure their ammonia in breath at home using the AmBeR breath measurement system. The team are also working towards improving the convenience of blood ammonia measurement by applying the same technology to a point-of-care blood measurement device. Studies are now being extended into measurements on patients with liver dysfunction.