A New Model for Animal Usage in Research

Written by Bioscribe and Labcyte on June 01, 2018

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Pharmacokinetic and pharmacodynamic safety testing relies heavily upon small animal models during the preclinical phase. Current assay approaches demand significant blood sample volumes as promising lead compounds are administered and tested across various time and/or compound dose courses. This often requires multiple animals per data course or, in extreme cases, as many as one animal per data point. Not only are there ethical considerations involved in this practice, but it can also result in increased experimental variability and overall study cost.

What if there was a better way?

As the world reflects on animal welfare during National Animal Rights Day, we wanted to share one of the great benefits of assay miniaturization enabled by our tipless liquid handling technology: Reducing animal usage.

By enabling smaller blood draws and increasing the number of data points generated per animal, “microsampling” can address the 3 R’s of animal welfare: Replace, Refine, Reduce.

Serial microsampling of animals from samples of 20 μL or less reduces the overall number of animals sampled and euthanized.

It is a significant improvement upon traditional composite studies in mice, which can require up to 700 μL of blood for each time point in a pharmacokinetic study, requiring the animals to be euthanized, with nine mice killed in a typical 9-point time course analysis.

Echo Acoustic Liquid Handling Technology enables blood sampling to be reduced by 5 to 50-fold, resulting in 89% reduction in animal needs.

Microsampling is also faster and less stressful than traditional composite studies. And, combined with reductions in compound consumption and decreases in study length, it can afford up to an 80% reduction in overall study costs.

How does it work?

As this poster presented at SLAS 2018 explains, researchers at F. Hoffmann-La Roche AG collected blood samples from mice through a vein in their tails, transferred them into PCR tubes, and separated out the plasma using a centrifuge. The plasma samples were then transferred into a Labcyte 384-Well Low Dead Volume Microplate and immediately sealed to prevent evaporation. Other wells of the same microplate were filled with blank plasma samples, pure DMSO, an internal standard and the analytical compound dissolved in DMSO at different concentrations (1000 µg/ml , 500 µg/ml , 50 µg/ml, 5 µg/ml, 0.5 µg/ml, 0.05 µg/ml).

The contents of the 384-Well LDV microplate were transferred using the Echo® Liquid Handler to an ABgene 384-well Storage plate, and a protocol to assemble a standard curve was created in the Echo® Dose-Response Software. Additional transfers were made until the samples were ready for downstream analysis using mass spectrometry.

They found they were able to use as little at 1 µL of plasma from mice vs 50 µL, with no loss of data quality.

In fact, the microsampling removed the animal-to-animal variability seen in composite collection studies by decreasing the number of subjects used within a study. It also meant they were able to utilize the same animals for PK and PD studies, resulting in better correlation between drug level and drug action.

In another Medimmune study, the use of the Echo Liquid Handler in peptide PK assays showed an increase of 88% data collected per animal. This gain was attributed to the elimination of peptides absorption to tips, requiring the use of less sample and directly resulting in the reduction in animal usage.

To learn more about microsampling, visit our web page and this app note.

 

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