title: Hepatic mitochondrial function analysis using needle liver biopsy samples.
abstract: OBJECTIVE
  Current assessment of pre-operative liver function relies upon biochemical blood tests and histology but these only indirectly measure liver function. Mitochondrial function (MF) analysis allows direct measurement of cellular metabolic function and may provide an additional index of hepatic health. Conventional MF analysis requires substantial tissue samples (>100 mg) obtained at open surgery. Here we report a method to assess MF using <3 mg of tissue obtained by a Tru-cut® biopsy needle making it suitable for percutaneous application.
  
  
  METHODS
  An 18G Bard® Max-core® biopsy instrument was used to collect samples. The optimal Tru-cut® sample weight, stability in ice-cold University of Wisconsin solution, reproducibility and protocol utility was initially evaluated in Wistar rat livers then confirmed in human samples. MF was measured in saponin-permeabilized samples using high-resolution respirometry.
  
  
  RESULTS
  The average mass of a single rat and human liver Tru-cut® biopsy was 5.60±0.30 and 5.16±0.15 mg, respectively (mean; standard error of mean). Two milligram of sample was found the lowest feasible mass for the MF assay. Tissue MF declined after 1 hour of cold storage. Six replicate measurements within rats and humans (n = 6 each) showed low coefficient of variation (<10%) in measurements of State-III respiration, electron transport chain (ETC) capacity and respiratory control ratio (RCR). Ischemic rat and human liver samples consistently showed lower State-III respiration, ETC capacity and RCR, compared to normal perfused liver samples.
  
  
  CONCLUSIONS
  Consistent measurement of liver MF and detection of derangement in a disease state was successfully demonstrated using less than half the tissue from a single Tru-cut® biopsy. Using this technique outpatient assessment of liver MF is now feasible, providing a new assay for the evaluation of hepatic function.
authors.affiliation: Department of Surgery, University of Auckland, Auckland, New Zealand.
authors.forename: Michael J J
authors.initials: MJ
authors.lastname: Chu
authors.forename: Anthony R J
authors.initials: AR
authors.lastname: Phillips
authors.forename: Alexander W G
authors.initials: AW
authors.lastname: Hosking
authors.forename: Julia R
authors.initials: JR
authors.lastname: MacDonald
authors.forename: Adam S J R
authors.initials: AS
authors.lastname: Bartlett
authors.forename: Anthony J R
authors.initials: AJ
authors.lastname: Hickey
mesh_terms: D000818:Animals; D001706:Biopsy / Q000379:methods; D004579:Electron Transport; D004734:Energy Metabolism; D006706:Homeostasis; D006801:Humans; D008111:Liver Function Tests / Q000379:methods*; D008297:Male; D008928:Mitochondria / Q000502:physiology*; D017208:Rats, Wistar; D015203:Reproducibility of Results