Tests for mitochondrial function and DNA: potentials and pitfalls.

PURPOSE OF REVIEW: In the past few years, mitochondria have been carefully studied to ascertain whether and how in patients affected by HIV antiretroviral therapy is able to alter their functionality and exert a toxic effect on immune cells, as well as on cells present in other districts. RECENT
FINDINGS: A variety of in-vivo and ex-vivo models have been developed to investigate the functionality of mitochondria and DNA during a variety of physiopathological situations, including HIV infection and its treatment. Numerous technologies are available to study at the single-cell or at the single-organelle level a variety of parameters, such as membrane potential, the activity of respiratory chain enzymes, and DNA content or its sequence. As far as in-vitro studies are concerned, a substantial homogeneity of data exists, and several changes in different mitochondrial parameters have been described that depend upon the drug used, the cell model and the parameter investigated. On the other hand, different results have been reported on biological material collected from HIV-positive patients and immediately analysed. Ex-vivo studies showed that changes in mitochondrial DNA content or in the functionality of the organelle exist in some tissues or cells, but not in others.
SUMMARY: One of the possible causes of the discrepancies is the technologies used to investigate mitochondria, and this paper summarizes some of the pros and cons of the main methods used to study mitochondrial function or DNA.