German researchers believe a nucleoside extracted from sugar cane could be the key to preventing and even reversing cell damage from HIV drugs.

The researchers believe that uridine — taken as part of a food supplement made from sugar cane extract — may be able to prevent HIV drugs from depleting the mitochondrial DNA of the body’s cells. The so-called mitochondrial toxicity of many HIV drugs is widely believed to be the cause of fat loss (lipoatrophy), and a range of other side effects including peripheral neuropathy, liver and pancreas damage and lactic acidosis.

Mitochondria are semi-independent ‘organelles’ which live at the centre of the body’s cells, and which provide the cells with energy. German researchers now theorise that the reason drugs such as d4T, ddI and ddC wreak so much havoc is because they directly inhibit an enzyme called polymerase gamma which is necessary for replication of the mitochondrial DNA (its genetic information). Over time, this will lead to a decrease in the total amount of mitochondrial DNA, and this in turn impairs the cells’ ability to function properly.

In test tubes, Ulrich Walker and his colleagues explored whether it is possible to stop the depletion of the mitochondrial DNA, preventing damage to cells and treating cells already damaged, by adding concentrations of uridine. They found that the uridine can protect cells from damage, and preserve their normal expression or appearance, even when the cells are exposed to ddC and d4T, two of the most notoriously toxic drugs.

In human trials, people were asked to drink a sugar cane extract called mitocnol, a supplement with a high percentage of nucleosides. There were no side effects except mild transient diarrhoea, and uridine serum levels increased after drinking the mixture.

Further clinical trials are planned to evaluate the effect and safety of the product, and to see whether it can indeed prevent treatment-induced mitochondrial toxicity in people with HIV.