No abstract

Background: There is a paucity of information regarding cardiac troponin (cTn) concentrations in peripheral blood of nonhuman primates (NHP). Even less is known regarding cTn concentrations in monkeys that are restrained for oral or intravenous (iv) dosing. Objectives: The objectives of these studies were to (1) determine cardiac troponin I (cTnI) concentration in resting Cynomolgus monkeys and investigate biologic variability in cTnI concentration over time, (2) determine cTnI changes in restrained monkeys given sham oral dosing, and (3) determine cTnI changes in restrained NHP given a sham intravenous dosing. Methods: The Research Use Only Erenna cTnI ultrasensitive immunoassay based on single molecule counting technology was used to determine serum cTnI concentration in longitudinal studies of male Cynomolgus monkeys at rest, and after sham oral and intravenous dosing. Animals were catheterized prestudy, and blood samples were collected by an automated sampling device to limit disturbance of the animals during studies. Results: In resting monkeys cTnI concentrations were relatively low and constant and ranged from 0.2 to 9.6 pg/mL (mean = 2.5 pg/mL), with minimal variability during a 24-hour period. Animals given sham oral dosing also had low cTnI concentration with little variability similar to the resting values. Several animals restrained for intravenous dosing had a small transient increase in cTnI concentration (~5-25 pg/mL) that resolved quickly within one to 3 hours postinjection. Conclusions: Results of this longitudinal study provide information that may be important in differentiating effects of animal handling from those associated with compound-related effects in preclinical toxicology studies of drugs in development.

-Purpose: Current practices applied to mouse pharmacokinetic (PK) studies often use large numbers of animals with sporadic or composite sampling that inadequately describe PK profiles. The purpose of this work was to evaluate and optimize blood microsampling techniques coupled with dried blood spot (DBS) and LC-MS/MS analysis to generate reliable PK data in mice. In addition, the feasibility of cross-over designs was assessed and recommendations are presented. Methods: The work describes a comprehensive evaluation of five blood microsampling techniques (tail clip, tail vein with needle hub, submandibular, retro-orbital, and saphenous bleeding) in CD-1 mice. The feasibility of blood sampling was evaluated based on animal observations, ease of bleeding, and ability to collect serial samples. Methotrexate, gemfibrozil and glipizide were used as test compounds and were dosed either orally or intravenously, followed by DBS collection and LC-MS/MS analysis to compare PK with various bleeding methods. Results: Submandibular and retro-orbital methods that required non-serial blood collections did not allow for inter-animal variability assessments and resulted in poorly described absorption and distribution kinetics. The submandibular and tail vein with needle-hub methods were the least favorable from a technical feasibility perspective. Serial bleeding was possible with cannulated animals or saphenous bleeding in non-cannulated animals. Conclusions: Of the methods that allowed serial sampling, the saphenous method when executed as described in this report, was most practical, reproducible and provided for assessment of inter-animal variability. It enabled the collection of complete exposure profiles from a single mouse and the conduct of an intravenous/oral cross-over study design. This methodology can be used routinely, it promotes the 3Rs principles by achieving reductions in the number of animals used, decreased restraints and animal stress, and improved the quality of data obtained in mouse PK studies.

Animal caretakers working in NHP areas must wear facial PPE to protect themselves from the zoonotic hazards related to splash exposures, but PPE that is uncomfortable may present its own risks. The authors evaluated the level of protection offered by several types of facial PPE against a variety of simulated facial mucocutaneous exposures of the sort that could occur during typical procedures in Old World NHP facilities and determined that less restrictive PPE can be used without compromising safety.