Thioflavin T, a dye used to stain protein aggregates, can extend the lifespan of roundworms and reduce effects of aging, like impeded movement. Silvestre Alavez and his coauthors report in a recent issue of Nature that Thioflavin T increases the median lifespan of roundworms (the nematode Caenorhabditis elegans) by about 60 percent and maximal lifespan by 43 to 78 percent. The effect is concentration dependent, as 50 or 100 µM doses increase life, while doses over 500 µM shorten it.

Besides Thioflavin T, other compounds that bind protein aggregates also extend the lifespan of roundworms, but to lesser extents. Chemicals like curcumin and rifampicin can extend roundworm life up to 45 percent. Compounds that have similar chemical structure to Thioflavin T, like HBX, HBT, and BM, reach maximum effects of lifespan extension at much lower concentrations than Thioflavin T, but can only extend life up to 40 percent.

Alavez and his team found that Thioflavin T lowers amyloid-β aggregation (associated with lesions in Alzheimer’s disease) and levels of other proteins that are prone to aggregation. But its effect on protein aggregates may not be directly related to its impact on longevity. Thioflavin T’s influence on lifespan seems to involve a stress response, since it relies on genes like HSF-1 (which regulates genes that respond to stress from heat) and SKN-1 (involved in oxidative stress resistance, protein homeostasis, and other stress-response functions).

The researchers also found that Thioflavin T acts independently of dietary restriction, which is another mechanism that has been linked to increasing lifespan.

As Alavez and his team have only conducted studies on microscopic roundworms, further experiments are necessary to determine if the effect of Thioflavin T can be extended to other animals, particularly those with a longer lifespan. Roundworms usually live less than 20 days, so it might be simpler to alter that number by large percentages. To change the lifespan of animals that live over a decade by 60 percent would be far more significant.

Nature, 2011. DOI: 10.1038/nature09873 (About DOIs)