Could avocados hold the key to treating leukaemia?

Behind the Headlines

Wednesday June 17 2015

Around 2,600 people are diagnosed with acute myeloid leukaemia each year in the UK

A compound found in avocado seeds could treat leukaemia

"Avocados could hold the key to helping beat rare form of leukaemia," The Independent reports; specifically acute myeloid leukaemia, which is an uncommon and aggressive cancer of the white blood cells.

The headline may give readers the impression that eating avocados may help fight leukaemia, which is not the case. Researchers were actually looking at a compound found in avocado seeds that is not eaten, called avocatin B, which appears to be effective against leukaemia cells in the laboratory.

The researchers tested 800 compounds against human leukaemia cells. Avocatin B was the most effective compound to cause the leukaemia cells to die. It did not have an effect on normal blood cells.

This is an exciting discovery and there are now plans to use this compound to begin development of a new drug, though of course this will be a long road.

Current treatments for leukaemias involve chemotherapy and, in some cases, stem cell transplants (previously, and somewhat inaccurately, known as bone marrow transplants). Stem cell transplants offer the chance of a cure. People aged between 16 and 30 can join the stem cell register, and if you are a match for a patient, you could save their life. The register is managed by the Anthony Nolan charity and you can find out how to register here.

 

Where did the story come from?

The study was carried out by researchers from the University of Waterloo and Mount Sinai Hospital in Canada and the University of Perugia in Italy. It was funded by the Leukemia & Lymphoma Society of Canada, the Natural Sciences and Engineering Research Council of Canada and the Canadian Institutes of Health Research.

The study was published in the peer-reviewed medical journal Cancer Research.

The media in general have reported on the study accurately though have not pointed out that the compound avocatin B was obtained from the seed of the avocado and not from the flesh that is eaten.

So headlines such as "An avocado a day keeps leukaemia away" are inaccurate and misleading.

 

What kind of research was this?

This was a laboratory study looking at the effect of an avocado extract on acute myeloid leukaemia.

Acute myeloid leukaemia is an aggressive cancer of the blood. Blood cells are made in the bone marrow from stem cells – the type of cells that are not specialised and can divide and produce a wide range of specialised cells. In acute myeloid leukaemia, there is an overproduction of myeloid white blood cells, which are usually involved in fighting infections.

When this system goes into overdrive, the bone marrow releases large numbers of immature myeloid blood cells into the circulation. They do not continue to develop into normal myeloid blood cells. The production of large numbers of these cells causes a reduction in the production of normal blood cells, which leads to the symptoms of leukaemia.

 

What did the research involve?

The researchers tested 800 natural health products against human acute myeloid leukaemia cells in the laboratory.

Human acute myeloid leukaemia cells were obtained and grown in dishes. They were then exposed to each of the products.

The most effective compound at causing leukaemia cell death was then tested on normal blood stem cells. These samples of peripheral blood stem cells were collected from healthy volunteers. They had been given a drug called G-CSF, which stimulates the body to produce increased numbers of these stem cells from the bone marrow and release them into the circulation.

The researchers then injected acute myeloid cells exposed to avocatin B into mice. They compared their ability to grow and develop in the bone marrow with acute myeloid cells that had not been exposed.

 

What were the basic results?

The compound avocatin B was effective in causing leukaemia cells to die. It was particularly effective against immature myeloid blood cells. It did not affect normal peripheral blood stem cells. When the researchers treated immature myeloid cells with avocatin B, their ability to develop in the bone marrow of mice was reduced.

The study authors say that previous research has found that the immature myeloid blood cells found in leukaemia contain more mitochondria than normal blood cells. Mitochondria are the specialised compartments in cells that generate energy. The experiments seemed to indicate that it was this difference that caused avocatin B to be effective against the leukaemia cells rather than normal blood cells.

Avocatin B is a compound made of two 17-carbon lipids that was extracted from avocado pear seeds.

How did the researchers interpret the results?

The researchers concluded that their laboratory studies demonstrated that avocation B "induced selective toxicity toward leukaemia and LSCs [leukaemia stem cells] with no toxicity toward normal cells".

 

Conclusion

This study has identified a compound that may lead to a new drug for treating acute myeloid leukaemia. As the research has only so far been conducted in a laboratory setting, it should be stressed that this is the beginning of a long road in drug development and may not necessarily lead to a successful treatment.

It is also important to note that the compound was extracted from the seed of the avocado and not from the flesh.

Current treatments for leukaemias involve chemotherapy and in some cases stem cell transplants.

Stem cell transplants offer the chance of a cure. People aged between 16 and 30 can join the stem cell register, managed by the Anthony Nolan charity, and if you are a match for a patient, you could save their life. Most people can donate stem cells via their blood, a process similar to donating blood itself. This is known as peripheral blood stem cell collection and is both painless and extremely safe.  

Analysis by Bazian. Edited by NHS Choices. Follow Behind the Headlines on Twitter. Join the Healthy Evidence forum.

Analysis by Bazian

Edited by NHS Choices

Links to the headlines

Avocados could hold the key to helping beat rare form of leukaemia. The Independent, June 16 2015

How avocado could help fight CANCER: Fat from the fruit 'targets leukaemia cells and stops them growing' - raising hopes for a new drug. Mail Online, June 16 2015

Links to the science

Lee EA, Angka L, Rota SG, et al. Targeting Mitochondria with Avocatin B Induces Selective Leukemia Cell Death. Cancer Research. Published online June 15 2015

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