Systems medicine: seeing the forest

As we learn more about how our bodies work, new medical advice keeps emerging that contradicts the old. One year estrogen replacement therapy is heralded as the best thing to treat osteoporosis; later it is seen as dangerous. The same drug that successfully treats an enlarged prostate causes problems during cataract surgery.

A lot of these contradictions stem from the complexity of the human body. Traditional clinical trials, while enormously useful, are based on a reductionist approach that ignores this complexity and tries to isolate the effect of a single input (a drug) on a single output (e.g., blood pressure). In a set of two PLoS articles, Andrew Ahn and colleagues explore the concepts behind a reductionist vs. systems-oriented approach in medicine:

While the implementation of clinical medicine is systems-oriented, the science of clinical medicine is fundamentally reductionist. This is shown in four prominent practices in medicine: (1) the focus on a singular, dominant factor, (2) emphasis on homeostasis, (3) inexact risk modification, and (4) additive treatments.

On a pratical front, Ahn discusses how systems medicine might be implemented in the clinic, as well as potential barriers to adoption. There are already many research efforts in systems biology, including those at The Institute for Systems Biology in Seattle and the Computational and Systems Biology Initiative at MIT. Leroy Hood has argued that a systems approach to medicine will lower costs by improving prevention and efficacy. How will systems-level thinking affect pharmaceutical development?