6.1.1 Understanding Disease Through Systems Thinking

Abstract

Angiotensin II is a hormone within the renin‐angiotensin system. Its effects in controlling blood pressure and thirst are universally recognized and well established. In the early part of this millennium we were somewhat puzzled to find that this blood pressure hormone had unforeseen apparently unrelated inflammatory effects and that an imbalance of this system was being implicated as a key driver not only in cardiovascular disease but in many diseases. Systems' thinking reveals a far more profound role for the renin‐angiotensin system in injury sensing, repair and development and provides an explanation for why it is closely associated with the inception and progression of all chronic inflammatory diseases (includes cancers, neurodegenerative diseases, chronic infections and autoimmune conditions). At some point in the future, manipulation of the angiotensin system, when used in synergy with other agents, will undoubtedly be used to far more effectively treat disease. The speed at which this goal is achieved will depend on our ability to adapt our thinking.