title: Impairment of mitochondrial respiration following ex vivo cyanide exposure in peripheral blood mononuclear cells.
abstract: OBJECTIVE
  The objective of this study is to measure mitochondrial respiration using intact cells from whole blood exposed to cyanide as a new biomarker for mitochondrial inhibition.
  
  
  METHODS
  A single nontourniqueted venous blood sample was collected from 10 healthy volunteers after informed consent. Venous lactate was measured immediately following blood collection. Half of the remaining blood sample was then incubated with 100 mM of potassium cyanide (KCN) for 5 min, and half of the sample remained unexposed. Repeat lactate measurements were performed from blood exposed and not exposed to KCN. Measurement of mitochondrial respiration: intact PBMCs were placed in a 2-mL chamber at a final concentration of 2-3 × 10(6) cells/mL. Measurements of oxygen consumption were performed at 37°C in a high-resolution oxygraph (Oxygraph-2k Oroboros Instruments, Innsbruck, Austria). Oxygen flux (in pmol O2/s/10(6) cells), which is directly proportional to oxygen consumption, was recorded continuously using DatLab software 6 (Oroboros Instruments).
  
  
  RESULTS
  There were significance differences in the relevant key parameters of mitochondrial respiration: Of the parameters measuring mitochondrial respiration, four of the six demonstrated a statistically significant mean difference between control and cyanide: for routine respiration (mean difference [control-cyanide]: 8.9 pmol O2/s/10(6) cells; 95% CI: 5.6-12.2, p < 0.0001); Proton Leak (mean difference: 0.73 pmol O2/s/10(6) cells; 95% CI: -0.33-1.79, p = 0.157); Maximal respiration (mean difference: 21.7 pmol O2/s/10(6) cells; 95% CI: 16.0-27.6, p < 0.0001); Residual oxygen consumption (mean difference 0.25 pmol O2/s/10(6) cells; 95% CI: -0.68-1.18, p = 0.557). There was a significant difference in spare respiratory capacity (SRC) and adenosine triphosphate (ATP)-linked respiration with the control samples demonstrating a higher SRC and ATP-linked respiration. Finally, there is a statistically significant difference in lactate (mean difference -0.32, 95% CI: -0.41 to -0.23, p < 0.0001), though clinically similar level, with a higher lactate concentration in the cyanide samples.
  
  
  CONCLUSIONS
  In this ex vivo model, the measurements of key parameters in mitochondrial respiration may be a more sensitive measure of cellular function when compared to lactate.
authors: a Department of Emergency Medicine , Center for Mitochondrial Bioenergetics in Emergency Medicine and Critical Care (MitoEM), University of Pennsylvania Perelman School of Medicine , Philadelphia , PA , USA ;
authors: David H
authors: DH
authors: Jang
authors: a Department of Emergency Medicine , Center for Mitochondrial Bioenergetics in Emergency Medicine and Critical Care (MitoEM), University of Pennsylvania Perelman School of Medicine , Philadelphia , PA , USA ;
authors: Frances S
authors: FS
authors: Shofer
authors: b Department of Anesthesia and Critical Care, Division of Critical Care Medicine , The Children's Hospital of Philadelphia, University of Pennsylvania Perelman School of Medicine , Philadelphia , PA , USA.
authors: Scott L
authors: SL
authors: Weiss
authors: a Department of Emergency Medicine , Center for Mitochondrial Bioenergetics in Emergency Medicine and Critical Care (MitoEM), University of Pennsylvania Perelman School of Medicine , Philadelphia , PA , USA ;
authors: Lance B
authors: LB
authors: Becker
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D007963:Leukocytes, Mononuclear / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D008928:Mitochondria / Q000187:drug effects*; D010101:Oxygen Consumption / Q000187:drug effects*; D011190:Potassium Cyanide / Q000633:toxicity*
chemical_list: D011190:Potassium Cyanide
keywords: Cardiovascular; complications of poisoning; metabolic; pharmaceuticals