No Need to Learn Latin! Understanding In Vivo, In Vitro, and Ex Vivo Techniques

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In vitro fertilization, ex vivo gene therapy, and in vivo clinical trials are exciting techniques in the medical field. The words that describe these methods (in vitro, in vivo, and ex vivo) are common adjectives used to describe research, treatments, or procedures. Although these words sound similar, they are distinct from each other and have unique uses and advantages. Let’s explore the meanings and uses of in vitro, in vivo, and ex vivo techniques.

In Vivo
In vivo describes when a study is done inside a living organism, such as a human or animal. In vivo is Latin for “within the living”. Clinical trials for medicines are often done in vivo because the conditions of a living organism cannot be replicated outside the body. Usually, in vivo treatments are tested on animals first, such as mice or rabbits, and if they produce the desired effects, clinical trials then open to humans. One advantage of in vivo clinical trials is that it shows the entire body’s response to a treatment or drug, including how the drug is metabolized by the body and the body’s response to the drug or treatment.

In Vitro
In vitro is Latin for “in glass”: it describes treatments that are done in a controlled environment such as a test tube or petri dish. The growth of cells, tissues, or bacteria that are in vitro is called a culture. Cultures are used extensively in the early stages of research because testing the responses of cells or tissues is much easier when they are isolated in a culture. Cultures can be easily replicated which is much cheaper than paying for living subjects to participate in an in vivo clinical trial! However, in vitro testing is mostly done in early stages of research because conditions in a petri dish or glass tube cannot show the effects of treatment on the entire body.

In vitro fertilization
In vitro fertilization (IVF) is a fertility treatment consists of extracting one or more eggs from a woman’s ovary and putting them into a petri dish with a man’s sperm. The dish is left in a controlled environment for three to five days, and then the fertilized egg is inserted into the woman’s uterus. She can then carry the embryo to full term within her body. IVF has helped women and men who struggle with fertility to have children with the assistance of a controlled environment outside the body, which is a great example of the advantages of in vitro treatments.

Ex Vivo
Ex vivo treatments combine elements of in vivo and in vitro to advance the boundaries of medical treatments and therapies. Ex vivo is Latin for “from life”: it involves cells or tissues taken from a living organism, such as a human or animal, and transports them into an artificial environment with very similar conditions. The new environment is as similar as possible to the body where the cells and tissues were extracted from so that they can later be implanted back into the body! An advantage of ex vivo treatments is that they provide conditions similar to in vivo experiments while benefiting from the isolation that in vitro methods have.

Ex vivo gene therapy
A revolutionary use of ex vivo methods is in the field of gene therapy, which prevents or treats disease by introducing new DNA into cells. Gene therapy is needed when the body has a defective gene and can’t produce necessary proteins. In ex vivo gene therapy, cells are taken from the body and exposed to a virus in an artificial environment. The virus inserts the gene into the cell’s DNA and the cell with the functioning gene is injected or transplanted back into the body. Ex vivo gene therapy has treated genetic conditions such as hemophilia and is being studied in clinical trials to determine whether it can be used to treat acquired diseases such as cancer.

In vivo, in vitro, and ex vivo describe the methods used for research and treatment and they differ in whether they take place inside the body or in a controlled environment such as a petri dish or test tube. The words may be in a different language but you don’t need to be an expert in Latin to understand how these methods are used to test new drugs and improve medical treatments!