A class of anti-retro-viral drugs commonly used to treat HIV/AIDS, particularly in Africa and low income countries, can cause premature aging, a new study has claimed. The study, published in the journal Nature Genetics, found that the drugs damage DNA in the patient’s mitochondria the ‘batteries’ which power their cells.
According to the researchers, the findings may explain why HIV-infected people treated with anti-retro-viral drugs sometimes show advanced signs of frailty and age-associated diseases such as cardiovascular disease and dementia at an early age.
“The DNA in our mitochondria gets copied throughout our lifetimes and, as we age, naturally accumulates errors. We believe that these HIV drugs accelerate the rate at which these errors build up,” said lead researcher Professor Patrick Chinnery from the Institute of Genetic Medicine at Newcastle University.
He said: “So over the space of, say, ten years, a person’s mitochondrial DNA may have accumulated the same amount of errors as a person who has naturally aged twenty or thirty years. “What is surprising, though, is that patients who came off the medication many years ago may still be vulnerable to these changes.”
Nucleoside analogue reverse-transcriptase inhibitors (NRTIs) — of which the most well known is Zidovudine, also known as AZT — were the first class of drug developed to treat HIV. They were a major breakthrough in the treatment of the disease, greatly extending lifespan and leading the condition to be seen as a chronic, rather than terminal, condition.
In high income countries, the older NRTIs are used less commonly now due to concerns over toxicity and side-effects. But, the drugs have proved to be an important lifeline for people infected with HIV in Africa and low income countries. Professor Chinnery said: “HIV clinics were seeing patients who had otherwise been successfully treated but who showed signs of being much older than their years. This was a real mystery.
“But colleagues recognized many similarities with patients affected by mitochondrial diseases — conditions that affect energy production in our cells — and referred them to our clinic.” In an attempt to understand what was happening at a cellular level, the researchers studied muscle cells from HIV-infected adults, some of whom had previously been given NRTIs.
They found that patients treated with NRTIs — even as long ago as a decade previously — had damaged mitochondria which resembled that of a healthy aged person. Co-author and HIV specialist, Dr Brendan Payne, also from Newcastle, believes that despite the side effects caused by NRTIs, they are still important drugs and the risks are relative.
“These drugs may not be perfect, but we must remember that when they were introduced they gave people an extra ten or twenty years when they would otherwise have died,” he says. “In Africa, where the HIV epidemic has hit hardest and where more expensive medications are not an option, they are an absolute necessity.” -Online