Internal Medicine Service

Research into canine liver disease

Research by the Dick Vet’s Medicine Team, along with colleagues at the Royal Veterinary College, has offered insight into why dogs may suffer from neurological abnormalities as a common complication of liver disease.

Abdominal scan

Liver disease is an important cause of ill-health in dogs. One of the most common complications of liver disease in dogs is neurological abnormalities, such as lethargy, altered gait, confusion and stupor. This syndrome is often termed hepatic encephalopathy (HE).

The presence of HE in dogs with liver disease can have a significant impact on their quality of life. This syndrome is a particular problem in dogs with a congenital portosystemic shunt (cPSS) (shown by arrow on image above in a computed tomography reconstruction of a cPSS). This is one of the most common congenital disorders we diagnose in our hospital and is due to the presence of an abnormal blood vessel, which diverts blood from the intestines away from the liver. Our previous studies have demonstrated that ammonia and inflammation are the key predictors for the development of HE in dogs.

Our recent study attempted to understand why dogs with liver disease frequently develop systemic inflammation. We were particularly keen to examine whether diverted blood from the gastrointestinal tract initiated systemic inflammation. We tracked haematological and biochemical parameters of inflammation in a large number of dogs with a cPSS before and after surgical ligation of the anomalous vessel.

Our study demonstrated that increasing blood flow to the liver was associated with a reduction in several populations of white cells in the blood, together with a decrease in circulating concentrations of a biomarker of inflammation termed C-reactive protein. The longitudinal nature of our study, where parameters of inflammation were measured before and after attenuation of the shunting vessel, has allowed us to demonstrate that intestinal derived factors are important in driving an inflammatory state in dogs with liver disease.

Understanding why dogs with liver disease develop systemic inflammation is important, since our previous studies have demonstrated that inflammation is an important predictor for the development of hepatic encephalopathy, which is one of the most debilitating complications of liver disease. Blood from the intestines normally flows directly to the liver, but in dogs with a congenital portosystemic shunt, an anomalous vessel diverts blood from the intestines directly into the general circulation, thereby bypassing the liver. Our study demonstrated that reducing the amount of blood that is diverted away from the liver results in a decrease in systemic inflammation. This provides evidence that the gut plays an important part in driving inflammation in dogs with liver disease.

Dr Richard MellanbyHead of Small Animal Medicine

The paper is published by PLoS ONE and is freely available on link below :