TY - JOUR T1 - Aldehyde Oxidase Activity in Donor Matched Fresh and Cryopreserved Human Hepatocytes and Assessment of Variability in 75 Donors JF - Drug Metabolism and Disposition JO - Drug Metab Dispos DO - 10.1124/dmd.114.057984 SP - dmd.114.057984 AU - J. Matthew Hutzler AU - Young-Sun Yang AU - Caitlin Brown AU - Scott Heyward AU - Timothy Moeller Y1 - 2014/04/08 UR - http://dmd.aspetjournals.org/content/early/2014/04/08/dmd.114.057984.abstract N2 - Studies were conducted to evaluate the impact of time and cryopreservation on aldehyde oxidase (AO) activity in human hepatocytes isolated from ten donor livers, using O6-benzylguanine as a probe substrate. In addition, variability in activity was assessed using cryopreserved hepatocytes from 75 donors. Substantial donor-dependent loss in AO activity within 24 hours following isolation of hepatocytes was observed (average loss of 42%, range 15-81%). Meanwhile, AO activity in cryopreserved hepatocytes more closely represented the activity observed in fresh hepatocytes that were incubated immediately following isolation for the same donors (within 81% of fresh, range 48-100%). Activity of AO in cryopreserved hepatocytes from 75 donors varied by at least 17-fold (≤5.4 to 90 mL/min/kg), with 63% of the donors having higher activity than a pooled 19-donor lot (34.2 mL/min/kg). When comparing demographics such as gender, body mass index, age, and ethnicity, no statistically significant correlations with activity were observed. Evaluation of medical histories uncovered that three out of the five donors with no measurable activity had immediate histories of extensive alcohol abuse. Meanwhile, two SNPs for AOX1 (rs3731772 and rs55754655) were detected in our donor pool and showed allelic frequencies similar to those reported from other cohort studies. However, these SNPs did not correlate with a statistically significant difference in intrinsic clearance compared to wild-type donors. With a general lack of clarity around what causes highly variable AO activity, pre-screening donors for AO activity, and creating a custom high-activity pooled lot of cryopreserved hepatocytes is advised to minimize under-predictions of clearance. ER -