Washington | HIV infection may prematurely age its sufferers by an average of five years, a new study has found. Thanks to combination antiretroviral therapy, many people with HIV can be expected to live decades after being infected.
Yet doctors have observed that these patients often show signs of premature ageing, researchers said. The new study has applied a highly accurate biomarker to measure just how much HIV infection ages people at the biological level – an average of almost 5 years.
The medical issues in treating people with HIV have changed, said Howard Fox, Professor at the University of Nebraska Medical Centre in the US. We’re no longer as worried about infections that come from being immunocompromised. Now we worry about diseases related to ageing, like cardiovascular disease, neurocognitive impairment, and liver problems, said Fox.
The tool used in the new study looks at epigenetic changes in people’s cells. Epigenetic changes affect the DNA, but not the DNA sequence. Once they occur, they are passed down from one generation of cell to the next, influencing how genes are expressed.
The particular epigenetic change used as a biomarker in this research was methylation, the process by which small chemical groups are attached to DNA. Methylation of DNA can impact how genes get translated into proteins. What we’ve seen in previous studies is that as we age, methylation across the entire genome changes, said Trey Ideker, Professor at the University of California San Diego.
Some people call it entropy or genetic drift. Although we’re not sure of the exact mechanism by which these epigenetic changes lead to symptoms of ageing, it’s a trend that we can measure inside people’s cells, said Ideker.
The 137 patients included in the analysis were enrolled in a long-term study aimed at monitoring HIV-infected individuals who are being treated with combination antiretroviral therapy. Subjects who were chosen did not have other health conditions that could skew the results. 44 HIV-negative control subjects were also included in the initial analysis.
An independent group of 48 subjects, both HIV positive and negative, was used to confirm the findings. In addition to the discovery that HIV infection led to an average advance in biological ageing of 4.9 years, the researchers note that such a change correlates with an increased risk of mortality of 19 per cent. We set out to look at the effects of HIV infection on methylation, and I was surprised that we found such a strong ageing effect, Ideker said.
Another thing that was surprising was that there was no difference between the methylation patterns in those people who were recently infected (less than five years) and those with chronic infection (more than 12 years), Fox added.