“Curry favour for your liver,” is the headline in the Daily Mirror. The newspaper said that mice fed curcumin (the chemical in turmeric that gives curry a yellow colour) had less liver damage over time than those on a normal diet.
The researchers in this animal study investigated how an extract of the spice protected mice that had been bred to have inflammation in their bile ducts from liver damage.
The results suggest that liver damage, jaundice and scarring were all reduced by the curcumin and that the underlying cellular pathways affected might, in time, become promising targets for new drug development. However, there is no suggestion from this study that eating turmeric will have the same effect or be a useful treatment for humans.
Where did the story come from?
This research was carried out by Dr Anna Baghdasaryan and colleagues from the Laboratory of Experimental and Molecular Hepatology at the Medical University Graz in Austria along with colleagues from Texas. The study was supported by the Austrian Science Foundation, the National Institutes of Health and the PhD Program of the Medical University of Graz. The study was published in the peer-reviewed medical journal Gut .
What kind of research was this?
This study was aimed at testing a mouse model of a group of diseases in humans known as chronic cholangiopathies. These diseases are caused by inflammation and scarring of the bile ducts within the liver, leading to the flow of bile to the gut being blocked, resulting in:
- liver cirrhosis
- liver failure
- liver cancer
Primary biliary cirrhosis is one example of a chronic cholangiopathy.
Curcumin, the yellow pigment of the spice turmeric, has been shown to have an effect on liver inflammation following injury. These researchers wanted to see if there were any beneficial effects of the chemical extract on mice bred to have a cholangiopathy.
What did the research involve?
The mice that were used are especially bred to have a type of chronic cholangiopathy (known as multidrug-resistant protein 2 knockout mice [Mdr2-/-]). These mice are used as models of progressive cholangiopathy with biliary fibrosis because they develop scarring and blockages of the bile ducts over time. The researchers tested liver enzymes, as a sign of liver inflammation, and examined the livers of male Mdr2-/- mice and wild-type mice before and after they were fed curcumin.
The researchers then cultured cholangiocytes (bile duct cells) and portal myofibroblasts (MFBs) another type of cell found in bile ducts, in the lab. The cells were then exposed to a chemical (TNF-alpha) that causes inflammation. This inflammation can be treated with a drug called troglitazone, a PPAR gamma antagonist. The researchers tested the cellular growth with and without curcumin and with and without troglitazone.
What were the basic results?
The researchers say that there was less liver damage, bile duct blockage and fibrosis in the Mdr2-/- mice after they were fed curcumin. They also found that curcumin prevented the cells in the bile ducts from growing.
In the lab, troglitazone was found to partially block the beneficial action of curcumin. The researchers suggest that this may be part of the chemical pathway that could be targeted for the development of new drugs. They also found that curcumin can prevent the portal myofibroblasts cells from multiplying. These cells are thought to play a central role in the development of inflammation in bile ducts.
How did the researchers interpret the results?
The researchers say their results show that curcumin may have multiple targets in the liver. They say they have described several central cellular events in a mouse model of cholangiopathy. They say that targeting these pathways may be a promising approach to treating cholangiopathies.
This well-conducted animal and laboratory study has identified cellular targets for new drug development. The theories are at an early stage and it is too soon to say that any new treatments might be developed from the spice. However, researchers will welcome these findings as they give a clear direction for new study into treatments for these severe and hard-to-treat conditions.
A variation of curcumin may be one of the drugs tested further; however, it is also possible that other related chemicals may have more effect. At this stage, it is not possible to say if the spice turmeric will be useful for treating liver disease in humans.