AEGiS-14IAC: Decline of mitochondrial DNA during therapy with nucleoside analogue reverse transcriptase inhibitors assessed by a single-tube NASBA simultaneously assaying both mitochondrial and nuclear DNA.

14th International AIDS Conference

Barcelona, Spain - July 7-12, 2002

Decline of mitochondrial DNA during therapy with nucleoside analogue reverse transcriptase inhibitors assessed by a single-tube NASBA simultaneously assaying both mitochondrial and nuclear DNA.

Int Conf AIDS 2002 Jul 7-12; 14:(abstract no. WeOrB1305)

de Ronde A, van Gemen B, Casula M, Timmermans E, van Dooren M, Westrop M, Dobbelaer I, Bakker M, Weverling GJ, Lange J, Goudsmit J, Reiss P
PrimaGen, Amsterdam, The Netherlands

BACKGROUND: Several of the adverse effects of antiretroviral therapy may result from inhibition of mitochondrial DNA polymerase gamma by nucleoside analogue reverse transcriptase inhibitors (nRTI's). Markers to measure mitochondrial toxicity in well accessible cells of the body like blood would be useful. OBJECTIVE. To examine the effect of therapy with nRTI's on the mitochondrial DNA content of PBMC. To meet this objective, development of a real time NASBA, which quantitatively measured the ratio between mitochondrial and nuclear DNA was initiated.

METHODS: A newly developed duplex single-tube real time NASBA which contained primers and beacons for a mitochondrial and a nuclear gene was used to assess the ratio between mtDNA and nDNA of PBMC. DNA was isolated from 10^5 patient PBMC. Samples were obtained from 48 HIV-1 infected antiretroviral naïve patients who within a double-blind clinical trial had been randomly allocated to treatment with AZT monotherapy or dual combinations of AZT+ddI, or AZT+ddC,

RESULTS: The duplex NASBA was able to discriminate and quantify small (< a factor 2) differences between the mtDNA content of samples of PBMC DNA. At start of therapy the 3 patient groups (AZT, AZT+ddI, AZT+ddC) did not differ significantly in the mtDNA content of their PBMC. However, already after 4 weeks of therapy the patient group on AZT+ddC therapy had 22 % lower mtDNA levels (p= .002) than at start. At 48 weeks after the start of therapy the mtDNA levels of the group on AZT-monotherapy remained stable, whereas the groups on dual therapy showed a decline of 16% (AZT+ddI, p= 0.02) or 25% (AZT+ddC, p= 0.04) compared to the mtDNA levels at start.

CONCLUSIONS: The newly developed duplex NASBA is able to quantify small differences in mtDNA content. We found that AZT-monotherapy does not cause a substantial change of mtDNA levels, whereas 48 weeks of simultaneous therapy with two nRTI's induced a decline of an average 20 percent the mtDNA content of patient PBMC.

Keywords: AEGIS, Reverse Transcriptase Inhibitors, Zidovudine, Didanosine, Zalcitabine, DNA, Mitochondrial, Single Person, Self-Sustained Sequence Replication, Antiretroviral Therapy, Highly Active, Mitochondria, DNA-Directed DNA Polymerase, DNA polymerase gamma, Human, therapy, drug therapy

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WeOrB1305