Experts study what parasites eat to find ways to kill them
Blocking the sugar intake of the parasites helps starve them and rid the patient's body of them.
Fri, Aug 05, 2011 at 03:57 AM
TOUGH TO KILL: A picture of leishmania. The parasite has developed a resistance to typical treatments, making it difficult to treat patients infected with them.. (Photo: Wikimedia Commons)
HONG KONG - Researchers in Australia are working on a technique that will allow them to starve to death parasites which are proving harder to destroy using existing drugs.
The parasite they used in the study was the leishmania, which is transmitted by the bite of the phlebotomine sandfly. After a period of incubation, the parasite causes huge skin sores, fever, anemia and damages the spleen and liver.
It affects 12 million people worldwide and has become more resistant to current drugs.
The scientists exposed the parasite to a large variety of food sources. Using highly sensitive equipment, they tracked how these nutrients were broken down and absorbed into the bodies of the parasites.
"Using this technique we found that Leishmania parasites are very dependent on the use of sugars for energy and growth. This was surprising as previous studies suggested that these parasites may be able to use a range of other nutrients for growth (such as amino acids and fats)," wrote lead author Malcolm McConville, a biochemistry and molecular biology professor at the University of Melbourne.
"They are therefore far more picky than we thought and therefore more vulnerable to therapeutic attack," he wrote in reply to questions from Reuters.
The team is hoping to use this food source as a way in to attack the parasite, which blights much of the Americas, Middle East and parts of Asia.
"We are interested in seeing whether we can develop new drugs that inhibit parasite sugar metabolism. These drugs would not only prevent parasites from growing and infecting new tissues, but would also make them vulnerable to host immune response," McConville added.
"The latter effect is important as Leishmania parasites can often induce a long term chronic infection that is very difficult to clear with current drugs. There is therefore a need to develop new drugs."
By observing how pathogens behave and thrive, scientists can explore ways to disrupt these processes to kill them. For example, there are certain anti-flu drugs to block viruses from entering and infecting human cells, and other drugs to stop newly-replicated flu viruses being released from infected cells.
In this experiment, McConville and colleagues observed what parasites ate, so they could seek ways to kill them by starving them of the very nutrients they need.
"It is directly applicable to looking at metabolism in other pathogens. For example, we are currently using it to investigate metabolism of the malarial parasite," McConville said.
The study was published in the current issue of the international Journal of Biological Chemistry.
(Reporting by Tan Ee Lyn, editing by Jonathan Thatcher)
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