In vitro versus in vivo

In vitro analysis involves experiments conducted outside of a living organism, typically in a test tube or petri dish. For example, in vitro experimentation can be used to test the reaction of living cells to a particular chemical or drug. In vitro experiments are also an integral component of biochemical studies, in which researchers try to determine the individual components required for basic biological activities, such as growth and immune response. The results of these in vitro studies can then be used to reassemble these biological puzzles in an organism – for instance, how the human body processes and utilizes vitamin C.

In vivo experiments, in contrast, are conducted in a living organism. In vivo protocols are used to evaluate the toxicity and efficacy of therapeutic drugs, or can be used to evaluate the effect of a gene mutation or deletion on an organism. Mice and rats are frequently used for in vivo analysis, as are zebrafish, fruitflies, and frogs.

Animal models versus human studies

The use of animal models to study human diseases has yielded vital information regarding the genetics, progression, and potential treatment of diseases as wide-ranging as cancer, diabetes, and Parkinson’s disease. However, these animal models are not perfect. For instance, drugs that have been effective for treating cancerous tumors in mice have proven ineffective in humans. Why is this? In the case of cancer genetics, key differences have been found between humans and mouse models in terms of aging processes and tumor suppressor mechanisms – most of which can be attributed to the extreme differences in lifespan between man and mouse. These subtle differences between the mouse experimental model and the human patient therefore become very important when developing new therapeutic drugs.

Because animal models are not perfect test-systems for potentially life-saving new drugs, it is essential to have a mechanism in which efficacy can be tested in humans. Such testing can be achieved either through clinical trials or through the use of biological materials from a biorepository.

Research studies using stored tissues

Biospecimen experimentation serves as an integral bridge between laboratory and applied research. The availability of high quality biospecimens allows a researcher to conduct a wide range of analyses that not only allow for a better understanding of the genetic and molecular changes involved in the progression of diseases, but can also be used for assessing the effectiveness of novel drugs and therapeutics in a particular patient population.

Thus, biorepositories play a key role in the pathway to the new era of personalized medicine, in which treatments will no longer be “one size fits all”, but instead “tailored” to the molecular and genetic profile of each patient.