Implanted telemetry is established as the gold standard for preclinical Drug Development, Safety Pharmacology and Toxicology studies.
This technique allows researchers to record physiological measurements from laboratory animals that were surgically implanted, and to transmit them wirelessly to a distant receiver and computer for monitoring and analysis.
Let’s understand how it evolved in the last decade and what are the current challenges faced by scientists.
The first generation of implanted telemeters were purely analog. These legacy implants transmitted data on a single frequency, which could lead to crosstalk between different subjects.
In addition, their limited transmission range prevented their use in larger cages where a “buddy” animal could interact with the subject under study.
The advent of digital telemetry, coupled with its ability to send data on different transmission channels and over longer distances, helped overcome these limitations and facilitated group housing.
In 1996, van Acker et al. compared implanted ECG monitoring to other approaches like morphometry and histology outcomes in a drug-induced cardiotoxicity study. The researchers showed that implanted telemetry studies could lead to a reduction of animal use by more than 90%1.
ECG monitoring via implanted telemetry provides higher sensitivity and reproducibility than alternative approaches by minimizing confounding factors such as anaesthesia and restraint or handler-induced stress.
Digital telemetry systems can usually be remotely controlled and configured, reducing human interaction at the minimum.
Furthermore, implanted telemetry enables longitudinal monitoring of sensitive and clinically relevant outcomes such as QT prolongation or arrhythmia identification.
We invite you to read our detailed Technical Note to better understand how social housing impacts the subject’s wellbeing and the quality of the data collected. In addition, we discuss the limitations and what the potential barriers to group-housing are.
Wireless technology permits a constant transfer of high volumes of digital data from freely moving animals group housed in rooms, cages, behavioural arenas, or even swimming during water-based tests (i.e., Morris Water Maze, Forced Swim Test).
Multiple physiological signals can be continuously and simultaneously recorded during several weeks or months depending on study design. The physiologic signals can include but are not limited to biopotentials (ECG, EEG, EMG), blood pressure(s), core body temperature, respiratory rate, and activity.
Methods development and results reporting are crucial in the quality and reproducibility of research findings. emka TECHNOLOGIES is here to provide you with reliable instrumentation and support, but having great tools is simply not enough if study design and reporting are not well thought out or designed.
There are two tools available to help with study design and report, as well as assess bias in preclinical animal studies, which are described below to include:
In the paper, “A systematic review on the reporting quality in mouse telemetry implantation surgery using electrocardiogram recording devices”, Alexandra Gkrouzoudi et al2 recently reviewed 234 studies using surgery that involves the placing of ECG recording telemetry devices in adult mice.
The publications used in this study were selected based on the ARRIVE guidelines (2010) and SYRCLE’S tool (2014) described above. Despite the publication of the ARRIVE guidelines in 2010, he found no significant improvement in the reporting quality.
Figure 1: The percentage of papers published until 2010 vs. 2011–2019 and the corresponding “Total Completeness Score” (0–40) in intervals of 4 points. Extracted from A systematic review on the reporting quality in mouse telemetry implantation surgery using electrocardiogram recording devices. Alexandra Gkrouzoudi et al. Physiology & Behavior (2022)
Preclinical animal studies that utilize telemetry and associate analysis tools can benefit from taking a holistic approach which includes ensuring that the right instrumentation/telemetry system is used and useful data is being extracted, but also ensuring that the study design, reporting and bias have also been taken into consideration.
* National Centre for the Replacement, Refinement and Reduction of Animals in Research
Article published in September 2022
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