Sunday, August 16, 2015

Breath test analyzer could help detect liver disease at early stage

In the journal EBioMedicine, a study led by the University of Birmingham in the UK suggests that high levels of a natural compound called limonene in the breath could be a sign of early-stage cirrhosis of the liver.

Researchers say that we already know that the breath of people with liver disease has a very distinct smell, and they wanted to find out what causes it. Now they have found a biomarker for the disease in limonene, they can continue to verify how good it is for diagnosing liver disease.

Limonene is a natural compound found in fruits and vegetables and in abundance in citrus fruits like oranges and lemons. It is also found in cosmetics, perfume and cleaning products and is used to flavor candies.

Because symptoms tend to be vague and often mild during the early stages, patients with liver disease do not usually seek medical advice until the condition is advanced and the liver is more damaged. Even then, symptoms can be mistaken for other diseases. They can include fatigue, jaundice, bleeding, swelling, bruising easily, confusion and nausea.

Cirrhosis is where continuous, long-term damage causes the liver to become so scarred it cannot function properly. The disease can lead to liver failure and cancer.

In the UK, where the new study took place, liver disease has risen sharply in recent decades to become the third biggest cause of early death, with 75% of deaths being alcohol related.

Breath levels of limonene higher in patients with liver cirrhosis

Researchers carried out their study in two phases. First, they compared breath samples from 31 patients with liver cirrhosis with those from 30 healthy controls.

In the second phase, they compared breath samples taken before and after liver transplants. The before samples came from the same 31 patients as in the first phase, and the after samples came from 11 of those patients who went on to have liver transplants.

The breath samples were analyzed with a mass spectrometer. For phase 1, this showed that the level of limonene in the patients with liver cirrhosis were much higher than in the healthy controls.

The researchers say this is probably because a diseased liver cannot fully metabolize limonene.

The phase 2 analysis showed that the levels of limonene gradually dropped in the transplant patients in the days following receipt of their new organ.

Limonene is 'unambiguously associated with diseased liver'

There have been previous attempts to find possible biomarkers for liver disease but these have suggested compounds like isoprene and acetone, which are not specific enough since they can also be indicative of other diseases or even arise naturally from normal metabolic activity.

Researchers wanted to find a biomarker that is unambiguously associated with diseased liver. If the 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.

A particularly important advantage of breath tests is that they offer the opportunity to assess the global function of the liver, rather than a localized test such as biopsy.

The study is important, because for the first time it opens a potential route to noninvasive, real-time detection of early-stage liver disease. The researchers conclude that If that is possible, then the disease could be reversed by drugs and lifestyle change which would lead to major socioeconomic impacts.


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