image: Caption: The study looked at the use of animal models for blood vessel formation in the choroid of the eye, and the need for new guidance and better reporting.
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In research on the AMD eye disease, the laboratory animals used are often young male mice. This is not optimal for the development of new treatments, because the disease most often affects older people – and women.

Eye disease Age-related macular degeneration (AMD) is the most common cause of vision loss and blindness in older people in the Western world.

The most aggressive form is “wet AMD”, a disease in which the formation of new blood vessels in the underlying choroid of the retina leads to fluid and swelling in the eye.

In a new study from Aarhus University that has just been published in the scientific journal Investigative ophthalmology and visual sciences (IOVS), the authors reviewed the last five years of studies in a disease model corresponding to 380 scientific articles. Research into the mechanisms behind disease – and therefore the development of new treatment modalities – is often based on laboratory animals, in which new blood vessels are artificially created in the retina, usually using of lasers.

Examination of numerous studies shows an imbalance in the use of laboratory animals; the researchers generally choose to use young, healthy male mice, although they know that the sex and age of the mice play a role in the degree of vessel formation.

“It is mainly young and healthy male mice that are used for research on this type of vessel formation. This makes sense from an ethical, financial, and time perspective because mice are inexpensive compared to larger laboratory animals, and studies can be done relatively quickly. Biological variation may also be limited. However, AMD is a disease that occurs most frequently in older people, and the disease occurs just as frequently in women – perhaps even a little more frequently, when looking at ‘wet AMD’,” explains the doctor. and PhD student Bjørn K. Fabian-Jessing, who is the study’s first author.

Previous studies have shown a discrepancy between the treatment effects seen in animal studies and in human clinical trials.

“We are apparently seeing a ‘translation gap’, as research is not taking place in the most relevant animal model. Greater biological variation could be achieved, for example, by using more female mice and/or older animals. This would likely increase the possibility of translating the research into clinical trials – and perhaps, ultimately, reduce the number of laboratory animals, as results from preclinical animal testing would then be easier to extrapolate.” , says Bjørn K. Fabian-Jessing. .

Poor reports

In addition to describing animal models, the article also focuses on the degree of notification.

“We can see that many studies do not report important variables, such as the number of mice used. It is therefore difficult to compare studies and assess the value of the results. This is worrying because it makes it impossible to reproduce the results, which decreases their reliability,” says Bjørn K. Fabian-Jessing.

Call for better guidelines

Data in the eye domain has not previously been collected and synthesized in this way.

“The new study calls for the development and updating of guidelines for these animal models,” says Bjørn K. Fabian-Jessing. He is supported by Professor Thomas Corydon, who is also behind the study:

“Implementing actionable guidelines will improve the quality, value and comparability of animal testing, which will naturally be of great benefit to the research, understanding and future treatment of eye disease,” says Thomas Corydon.

It encourages leading researchers in the field to develop consensus guidelines, as has already been done for preclinical research in other medical specialties.

“The implementation of higher methodological standards, greater biological variability within animal models and a greater degree of relevant and detailed reporting will result in higher quality research, which will be more directly comparable. In this way, the overall research field can work better in the same direction – for the benefit of patients, and perhaps with the help of fewer laboratory animals, because there will be fewer wasted experiments”, explains Thomas Corydon.

Behind the search results

Medical student and PhD Bjørn Kristensen Fabian-Jessing

Aarhus University, Department of Biomedicine

Email: [email protected]

Professor Thomas Corydon

Aarhus University, Department of Biomedicine

Such. : +45 2899 2179

Email: [email protected]

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