title: Changes in mitochondrial DNA as a marker of nucleoside toxicity in HIV-infected patients.
abstract: BACKGROUND
  Nucleoside analogues can induce toxic effects on mitochondria by inhibiting the human DNA polymerase gamma. The toxic effects can range from increased serum lactate levels to potentially fatal lactic acidosis. We studied changes in mitochondrial DNA relative to nuclear DNA in the peripheral-blood cells of patients with symptomatic, nucleoside-induced hyperlactatemia.
  
  
  METHODS
  Total DNA was extracted from blood cells. A nuclear gene and a mitochondrial gene were quantified by real-time polymerase chain reaction. Three groups were studied: 24 controls not infected with the human immunodeficiency virus (HIV), 47 HIV-infected asymptomatic patients who had never been treated with antiretroviral drugs, and 8 HIV-infected patients who were receiving antiretroviral drugs and had symptomatic hyperlactatemia. The patients in the last group were studied longitudinally before, during, and after antiretroviral therapy.
  
  
  RESULTS
  Symptomatic hyperlactatemia was associated with marked reductions in the ratios of mitochondrial to nuclear DNA, which, during therapy, averaged 68 percent lower than those of non-HIV-infected controls and 43 percent lower than those of HIV-infected asymptomatic patients never treated with antiretroviral drugs. After the discontinuation of antiretroviral therapy, there was a statistically significant increase in the ratio of mitochondrial to nuclear DNA (P=0.02). In the patients followed longitudinally, the decline in mitochondrial DNA preceded the increase in venous lactate levels.
  
  
  CONCLUSIONS
  Mitochondrial DNA levels are significantly decreased in patients with symptomatic, nucleoside-related hyperlactatemia, an effect that resolves on the discontinuation of therapy.
authors.affiliation: British Columbia Centre for Excellence in HIV/AIDS, University of British Columbia, St. Paul's Hospital, Providence Health Care, Vancouver, BC., Canada.
authors.forename: Hélène C F
authors.initials: HC
authors.lastname: Côté
authors.forename: Zabrina L
authors.initials: ZL
authors.lastname: Brumme
authors.forename: Kevin J P
authors.initials: KJ
authors.lastname: Craib
authors.forename: Christopher S
authors.initials: CS
authors.lastname: Alexander
authors.forename: Brian
authors.initials: B
authors.lastname: Wynhoven
authors.forename: Lillian
authors.initials: L
authors.lastname: Ting
authors.forename: Hubert
authors.initials: H
authors.lastname: Wong
authors.forename: Marianne
authors.initials: M
authors.lastname: Harris
authors.forename: P Richard
authors.initials: PR
authors.lastname: Harrigan
authors.forename: Michael V
authors.initials: MV
authors.lastname: O'Shaughnessy
authors.forename: Julio S G
authors.initials: JS
authors.lastname: Montaner
mesh_terms: D000328:Adult; D019380:Anti-HIV Agents / Q000009:adverse effects* / Q000097:blood; D004247:DNA / Q000097:blood; D004272:DNA, Mitochondrial / Q000097:blood / Q000187:drug effects*; D015224:Dideoxynucleosides / Q000009:adverse effects* / Q000097:blood; D004359:Drug Therapy, Combination; D064420:Drug-Related Side Effects and Adverse Reactions / Q000175:diagnosis*; D005819:Genetic Markers / Q000187:drug effects; D015658:HIV Infections / Q000097:blood / Q000188:drug therapy* / Q000235:genetics; D006801:Humans; D019344:Lactic Acid / Q000097:blood*; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D016133:Polymerase Chain Reaction / Q000379:methods
chemical_list: D019380:Anti-HIV Agents; D004272:DNA, Mitochondrial; D015224:Dideoxynucleosides; D005819:Genetic Markers; D019344:Lactic Acid; D004247:DNA