Challenges Faced by Animal Researchers

Today, I have decided to look a little deeper into the common flaws with the scientific method commonly used with animal research as identified by C.R. Hoojimans in his article, “Progress in Using Systematic Reviews of Animal Studies to Improve Translational Research”.  In his article, he identified five common problems that stand in the way of researchers translating animal testing results to human applications:

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           (1) Biological differences between species and strains

Genetic and species differences between animals and humans, but also within animal species, strains, and cell lines are often disregarded in the design of animal studies. Ignoring biological differences between species and strains results in flawed design and unreliable outcomes, incurs unnecessary costs, and uses more experimental animals than necessary.

·         (2) Poor methodological quality of animal experiments

In many animal experiments, important methodological issues, such as randomization and blinding, are neglected. In addition, the statistical methods used to analyze results are often flawed. These failures mean that basic research cannot be replicated and may cause an overestimation of the efficacy of interventions. Although clinical trials in humans also suffer from biases, preclinical animal studies appear to be associated with even greater risks.

·         (3) Differences in the design of experimental animal studies and clinical trials

Animal studies designed to decide whether or not to take an intervention forward to clinical trials, use study protocols that differ from clinical studies. For example, many of the animal studies investigating the effect of probiotics on pancreatitis administered probiotics before inducing pancreatitis, whereas in the clinical trial probiotics were given to patients already presenting with signs of pancreatitis.

·         (4) Insufficient reporting of details of animals, methods, and materials

Characteristics of the design of animal studies, such as the strain, gender, age and weight, and housing conditions of the animals used, are known to influence results. Failures in reporting these details skew the interpretation of study results and subsequent translation into clinical benefits.

·         (5) Publication bias

Not reporting experiments with negative or neutral results leads to an overestimation of the effect of an intervention. Publication bias plays a role in both clinical trials and animal studies, but is believed to be more problematic in animal studies. In experimental stroke studies, for example, an estimated 14% of animal studies are unreported.

Each of these challenges are very real concerns.  If most of what we know from animal research suffers from practices such as these, how can we consider them reliable?  I do not doubt that these challenges exist, but I believe most of them are avoidable.  Challenge 1 is obviously never going to go away as long as there is animal research.  Challenge 2 is just poor application of the scientific method and very avoidable.  Perhaps this challenge exits because of the considerable cost associated with using several animals all at once to establish things like control groups.  Challenge 3 addresses the fact that we are trying to replicate conditions experienced by humans and so it only makes sense that those same conditions must also be experienced by the animals as well.  However, it may be impossible to replicate real world human conditions for an animal.  Challenge 4 is one of the things I question immediately when some kind of new revealing study emerges because I think there are always more factors at play then just the single factor being focused on.  Challenge 5 is probably the most threatening in my opinion.  All the other challenges can be over overcome, but if the reporting of the results is done so with bias or prejudice, the results can be nullified or altered.