Alzheimer's drug- A new hope for treating Chagas disease in patients with chronic illness: PLOS

Brazil: Chagas disease is a neglected tropical disease (NTD) which contributes to approximately 10,300 deaths annually in endemic countries such as Latin America. Drugs used in the treatment of this disease have serious side-effects as well as have limited use in patients with chronic illness. A new study reported in the PLOS Neglected Tropical Diseases has brought new hope for the people who are at high risk of acquiring Chagas disease. The study has found that memantine, a drug currently used to treat Alzheimer's disease, can diminish the number of parasites in mice with Chagas disease, and increase the survival rate of the animals.

A protozoan, Trypanosoma cruzi, causes Chagas disease. It is spread mostly by insects known as Triatominae, or "kissing bugs". Chagas disease affects 8 to 10 million people living in endemic Latin American countries, with an additional 300,000–400,000 living in nonendemic countries, including Spain and the United States. An estimated 41,200 new cases occur annually in endemic countries, and 14,400 infants are born with congenital Chagas disease annually. The disease can be divided into acute and chronic phases, with the clinical phase causing heart, esophagus or intestinal symptoms. The two drugs that have been used to treat Chagas for the last 50 years--nifurtimox and benznidazole--are highly effective in the acute phase but used sparingly in the chronic phase due to serious side effects that occur with long-term treatment.

In the new work, Ariel M. Silber of Universidade de São Paulo, Brazil, and colleagues studied memantine, which works on the central nervous system of animals but has also been shown to kill protozoa. The researchers first studied the effect of different concentrations of memantine on cultured macrophages-- a type of white blood cell--that were infected with T. cruzi. Next, they tested the drug in T. cruzi-infected mice.

The team found that memantine reduced the number of T. cruzi-infected macrophages in a dose-dependent way; more drug led to a greater reduction in the infection. In mice with Chagas disease, memantine lowered levels of the parasite by 40% and increased survival rates from 7.5% to 12.5%. The mice treated with memantine also had 35.3% lower parasite levels in their hearts compared to control animals.

"All these findings point memantine as an interesting starting point for the development of an optimized alternative therapy for Chagas disease," the researchers say.

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DOI: 10.1371/journal.pntd.0007226