In Vitro

The strict translation of in vitro from Latin is “in glass.” Historically, in vitro studies were carried out in glass containers (test tubes, beakers). Now, in vitro [Page 891]research refers to research performed in an artificial environment and refers to experiments in culture media, petri dishes, or other controlled environments outside of living organisms.

In vitro research is common to formal laboratory settings. Because of the controlled environment, there are typically fewer variables and results are easier to distinguish. An advantage of this type of research is the ability to focus on specific component parts of organisms and how they function. Often, in vitro research is centered on one modification and the subsequent reaction upon the specific cellular component being tested. For example, in vitro studies could be used to discern function of specific enzymes and receptors. In addition, in vitro research is typically less expensive to perform and yields results that can be extended into different fields of technology. Initial pharmaceutical research is typically done in vitro, as metabolic pathways are better defined and the mechanism of action delineated. This background is necessary prior to the creation of new medications.

One current use of in vitro technology is in vitro fertilization (IVF). Infertility is typically defined as inability to conceive within 12 months of unprotected intercourse. Couples with certain types of infertility have achieved pregnancy using this technique. Specifically, a patient's ovaries are stimulated with a particular hormone to cause ovulation and maturation of eggs. Then, the eggs are surgically retrieved and fertilized with sperm in an in vitro laboratory setting, typically in petri dishes. The fertilized eggs become zygotes and typically, when they develop into six- to eight-cell embryos (approximately two to three days later), they are then transferred to the patient's uterus with the intent to progress to a successful pregnancy. Potential risks of IVF may include difficulties with the medication to initially stimulate the ovaries (resulting in either lack of ovulation or ovarian hyperstimulation syndrome), operative risks in obtaining the eggs or transferring the embryos, lack of adequate fertilization or progression to viable embryos, multiple gestations, other complications of pregnancy, and psychological stress. Additionally, the several-step procedure of IVF is expensive, and may be cost prohibitive to some couples, as insurance coverage for the management of infertility varies between different carriers and different states.

In vitro fertilization (IVF) has enabled couples with certain types of infertility to achieve pregnancy through this method.

The controlled environment of in vitro studies is sometimes a disadvantage when drawing conclusions as to how living organisms will respond with the same modification. Because living organisms may have multiple other adaptations related to the experimental change, sometimes results of in vitro studies are not only inaccurate, but they can be completely unpredictable. In fact, over time, uses of pharmaceuticals tested in vitro can change dramatically over time. A recent prominent example of this is aspirin. Initially, the synthetic drug was used as an analgesic. For the 100 years following its discovery, its uses increased and in the last 30 years aspirin has been recognized to reduce the risk of all vascular events (myocardial infarction, stroke, and deep vein thromboses) by about one-third. Therefore, results from studies performed in vitro do not always show precisely how living organisms will respond; because of this it may be difficult to draw conclusions from in vitro studies directly to living organisms and to how they actually respond internally.

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