Navigation Links
Viral 'fitness' explains different resistance patterns to aids drugs

Some HIV medications lead to the development of drug-resistant HIV when patients take as few as two percent of their medications. For other medications, resistance occurs only when patients take most of their pills. These differences appear to be explained by the different levels of viral "fitness" of the drug-resistant HIV, say AIDS researchers in a new study.

The research, led by David Bangsberg, MD, MPH, an AIDS specialist at the University of California, San Francisco, is reported in the January 9 issue of the journal AIDS.

Viral "fitness" refers to the inherent ability of a virus to replicate and cause disease. Incomplete pill-taking by patients causes HIV to mutate and become resistant to the effects of the medications, while the medications that were consumed, in turn, cause the newly resistant virus to become less fit.

The type of medication also factors in. Differences in viral fitness of mutated resistant virus occur between different classes of antiretroviral drugs, said Bangsberg, who is an associate professor of medicine at UCSF and director of the UCSF Epidemiology and Prevention Interventions Center at San Francisco General Hospital Medical Center.

When patients succeed in completely suppressing HIV, which requires that patients take all or almost all of their medications as directed, resistant strains either do not occur or are suppressed, he added.

Explaining the study results, Bangsberg said, "A non-nucleoside reverse transcriptase inhibitor (NNRTI), for example, can be taken one time by a pregnant woman to prevent mother-to-child transmission, and NNRTI-resistant HIV virus can develop. Yet patients taking unboosted protease inhibitors (PI) do not experience the peak risk of PI-resistant HIV developing unless they are taking most of their PIs but fall just short of full viral suppression."

The researchers found that NNRTI-resistant virus has an advantage over sensitive virus even at very low levels o f adherence. This happens because only a single mutation is required to create high-level NNRTI resistance and these mutations have little impact on the virus's ability to replicate. PI-resistant virus, in contrast, requires multiple mutations, each of which significantly weakens the ability of the virus to replicate. These PI-resistant viruses only emerge, therefore, when challenged with high concentrations of drug.

Overall, study findings showed that NNRTI resistance was found less often than PI resistance among patients who took the pills as directed.

"We believe that when new drug classes are developed, more attention should be given in defining how virologic fitness determines how different patterns of taking medications may lead to resistance" said Steven Deeks, MD, associate professor of medicine at UCSF's Positive Health Program at SFGHMC and senior author on the study.

Both NNRTIs and non-boosted protease inhibitors are potent antiretroviral drugs (ARVs) with demonstrated effectiveness in suppressing the HIV virus when taken in combination with other ARVs at high levels of pill-taking as directed. The standard combination therapy usually includes either one NNRTI or protease inhibitor (non-boosted or boosted with a small amount of another potent PI) and two different antiretrovirals from the nucleoside reverse transcriptase inhibitor class.


'"/>

Source:University of California - San Francisco


Related biology news :

1. Viral DNA sequence a possible trigger for breast cancer
2. NYU Study Reveals How Brains Immune System Fights Viral Encephalitis
3. Viral protein influences key cell-signaling pathway
4. Viral protein helps infected T cells stick to uninfected cells
5. Viral genetic differences are possible key to HIV dementia
6. Viral hitchhiker inhibits Wolbachia bacterias ability to proliferate
7. Viral marker of human migration suspect
8. Viral protein is an effective preventative against infection
9. Gene sequencing explains bioremediation bug
10. New book explains antibiotic resistance for a broad audience
11. UGA study explains peaks and troughs of dengue epidemics
Post Your Comments:
*Name:
*Comment:
*Email:


(Date:3/15/2016)... New York , March 15, 2016 ... new market report published by Transparency Market Research "Digital Door ... Trends and Forecast 2015 - 2023," the global digital door ... US$ 731.9 Mn in 2014 and is forecast to grow ... 2023. Growth of micro, small and medium enterprises (MSMEs) across ...
(Date:3/14/2016)... -- NXTD ) ("NXT-ID" or the "Company"), a ... airing of a new series of commercials on Time Warner ... st .  The commercials will air on Bloomberg TV, Fox ... Street show. --> NXTD ) ("NXT-ID" or the ... announces the airing of a new series of commercials on ...
(Date:3/11/2016)... HANOVER, Germany , March 11, 2016 ... - Cross reference: Picture is available at AP Images ( ... scanner from DERMALOG will be used to produce the new refugee ... of other biometric innovations, at CeBIT in Hanover ... LF10 scanner from DERMALOG will be used to produce the new ...
Breaking Biology News(10 mins):
(Date:5/26/2016)... , ... May 26, 2016 , ... ... company, today announced several positive developments that position the Company for the future. ... of the transaction, Craig F. Kinghorn has been appointed Chairman of the Board, ...
(Date:5/25/2016)... ... May 25, 2016 , ... Founder of the Fitzmaurice ... surgery and surgery of the hand by the National Board of Physicians and ... above and beyond in his pursuit of providing the most comprehensive, effective treatment ...
(Date:5/25/2016)... (PRWEB) , ... May 25, 2016 , ... ... U.S. Food and Drug Administration (FDA) has granted the company’s orphan drug designation ... company’s second orphan drug designation granted by the FDA. , Spinocerebellar ataxia ...
(Date:5/23/2016)... , ... May 23, 2016 , ... The need for blood donations in South Texas ... by the South Texas Blood & Tissue Center, blood donations are on the decline. In ... and they are down 21 percent in South Texas in the last four years alone. ...
Breaking Biology Technology: