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Major growth reduction and minor decrease in mitochondrial enzyme activity in cultured human muscle cells after
N H Herzberg1, I Zorn, R Zwart
1Department of Neurology, Academical Medical Center, Amsterdam, The Netherlands.
Muscle & Nerve
|June 1, 1992
Summary
Zidovudine significantly inhibits muscle cell proliferation, not mitochondrial DNA replication, explaining myopathy in AIDS patients. This finding impacts understanding of zidovudine
Area of Science:
- Biochemistry
- Cell Biology
- Virology
Background:
- Zidovudine is an antiretroviral medication used to treat HIV/AIDS.
- Mitochondrial myopathy has been reported in AIDS patients treated with zidovudine.
- The exact mechanism of zidovudine-induced myopathy is not fully understood.
Purpose of the Study:
- To investigate the effects of zidovudine on human muscle cells in culture.
- To determine if zidovudine inhibits mitochondrial DNA (mtDNA) replication or affects cell proliferation.
- To examine the impact of zidovudine on mitochondrial and nuclear-encoded enzyme activities.
Main Methods:
- Cultured human muscle cells were exposed to varying concentrations of zidovudine.
- Cell proliferation was assessed.
- Activities of mitochondrial citrate synthase and cytochrome c oxidase were measured.
- mtDNA content and integrity were analyzed.
Main Results:
- Zidovudine markedly inhibited muscle cell proliferation, even at low concentrations (10 µmol/L).
- Nuclear-encoded citrate synthase activity remained unaffected.
- Partially mitochondrial-encoded cytochrome c oxidase activity decreased only at high zidovudine concentrations (5 mmol/L).
- No decrease in mtDNA content or evidence of mtDNA deletions was observed.
Conclusions:
- Zidovudine's adverse effects on muscle in AIDS patients likely stem from reduced muscle cell proliferation.
- Inhibition of mtDNA replication is not the primary mechanism behind zidovudine-induced myopathy.
- These findings suggest a need to re-evaluate the management of zidovudine therapy in AIDS patients.