A natural compound called limonene, which is found in oranges and lemons, could be indicative in early-stage diagnosis of liver disease, according to research published in the journal EBioMedicine.
Limonene occurs in the greatest abundance in citrus fruits, but it is also found in a large variety of other fruit and vegetables. It can be ingested or inhaled as it is a common additive in commercial food and drinks, is used to give the fruit flavour to some sweets and is used in cosmetics, perfumes and cleaning products.
Liver disease has risen sharply over the past few decades. Patients do not often present with symptoms until the disease is advanced. Even then diagnosis is difficult and the symptoms and signs are often general and can be mistaken for other pathologies. For advanced cirrhosis liver transplant is the only treatment.
The new study was carried out in two phases - breath samples from a group of 31 patients suffering from cirrhosis were first compared with a healthy control group. Then pre-transplant samples of the liver disease sufferers were compared with a sub-cohort of 11 patients who went on to have a liver transplant.
When the patients were tested before transplant surgery, the level of limonene in the breath was found to be very high - higher than in a healthy person. This resulted from patients being unable to fully metabolize limonene.
When the team tested the same patients who had received a new liver, the tests showed that the limonene levels gradually dropped over several days. The researchers deduced that the unmetabolized limonene had been stored in the body fat of people suffering with cirrhosis.
To carry out the test, the patients and control group were asked to provide breath samples, which was then put into a highly sensitive analytical instrument that measures the intensities of 'aroma molecules' or molecules that give rise to the experience of smell.
"We already knew that people with liver disease have a very distinct smell on the breath and we wanted to find out what caused that smell. Now that we have found a biomarker for the disease in limonene, we can continue to verify how good it is for diagnosing liver disease. If our further research is successful, in the future we can envisage a small portable breath analyser that can be used by GPs and other health professionals to screen for early stage liver disease, leading to earlier treatment and better survival rates," the researchers said.
The researchers, together with KORE Technology Ltd, are now seeking additional funding to continue this research programme to evaluate the diagnostic accuracy of breath volatile analysis for early stage cirrhosis.
Based on material originally posted by University of Birmingham.