Fruit flies get kidney stones

When exposed to certain dietary foods, fruit flies rapidly and reliably get kidney stones.

Researchers from the University of Glasgow and the Mayo Clinic in America have shown that Drosophila can also get kidney stones – an agonising ailment in humans which doesn’t appear to bother the flies one bit.

Glasgow’s Professor Julian Dow has also been able to follow the real-time formation of kidney stones under the microscope.

“Unlike the human kidney, the simple fruit fly kidney tubule is easily accessible and transparent; and unlike us, fruit flies seem quite unconcerned by the presence of stones,” said Dow. “This means that we can now screen fruit flies for compound that can stop new stones forming, and so one day perhaps we will be able to offer protection against recurrence for patients with a history of stone formation.”

There is a 60% risk of recurrence of kidney stones – even after high strength pain killers and ultrasound – and preventative treatments have been hindered by and inability to find a suitable model system – stones are just as agonising for lab animals as humans.

The teams have identified a gene which encodes a protein that transports oxalate into the fly kidney – when knocked down genetically, the fly gets fewer stones. This means the group have a specific target to study as a candidate for drug development.

Dow and Davies’ labs are now successfully modelling a class of diseases called inborn errors of metabolism – for example rosy, a well-known mutant , develops orange kidney stones and deformed kidney tubules just like the rare human genetic disorder xanthinuria. In collaboration with Strathclyde Unversity, they are using the new science of metabolomics to study how such mutations cause some compounds to accumulate to very high levels, while others are severely depleted.

“Our hope is that, by using a relatively inexpensive and flexible disease model like Drosophila we can help with at least some of these important diseases,” said Dow.