New Delhi, May 20: A drug approved for years for the treatment of rheumatoid arthritis may also be effective against an intestinal infection that causes amoebic dysentery, research by a Calcutta-educated biologist now in the US has suggested.
A rapid drug screening technique developed by Anjan Debnath at the University of California, San Francisco, has helped researchers discover that a medicine called auranofin blocks the growth of the intestinal parasite, Entamoeba histolytica.
Debnath and his colleagues from institutions in the US and Mexico have shown that auranofin, an oral drug used to treat arthritis, is 10 times more powerful against this parasite than metronidazole, the standard drug used to treat the infection.
Their study results were reported today in the journal Nature Medicine.
Public health specialists believe that about 50 million people worldwide are infected with Entamoeba histolytica through contaminated food or water each year, and amoebiasis is the fourth leading cause of death from protozoan infections, accounting for an estimated 70,000 deaths each year. While metronidazole is effective, doctors are concerned that the parasite may turn resistant to this drug.
The new research based on laboratory and animal experiments suggests that auranofin, which has been used as a therapy for rheumatoid arthritis in adults since the late-1980s, may emerge as a medication for the treatment of amoebic dysentery.
Debnath, who had studied at the Ramakrishna Mission Boys High School in Rahara, a Calcutta suburb, and the University of Calcutta, developed a new technique to screen a large number of chemical compounds against the amoeba quickly.
This high-throughput screen allowed the researchers to grow the amoeba in tiny volumes of nutrient broth in an oxygen-free environment that mimics the amoeba’s natural environment. The scientists screened 910 compounds and found auranofin the most promising.
Debnath said he’s been interested in this organism for years.
“It’s a major health problem across India, especially in West Bengal — almost everyone is aware of this disease or has experienced the infection in Bengal. But it is also a remarkable organism for what it does in the human intestine,” Debnath told The Telegraph.
“It can ingest red blood cells, destroy enzymes, and kill intestinal cells,” he said.
In their experiments, the scientists used animal models of amoebic colitis to demonstrate the efficacy of auranofin against the parasite at doses that were less than the standard treatment doses of metronidazole.
“The identification of a drug that has already been approved by regulatory authorities and one which has a proven safety record can help us avoid an expensive and prolonged drug development process,” said Debnath, a post-doctoral researcher at the University of California, San Francisco (UCSF).