**2. Inflammation**

The answer to the fundamental question 'What is Inflammation?' is, of course, complex. For many years, discussion on inflammation revolved around the immune system and the ability to distinguish 'self' from 'non-self'. This required an understanding of the ancient 'innate' immune system and the 'adaptive' immune system. There has been a sea change in thinking over the past three decades towards an appreciation of a primary role in the initiation of the inflammatory response residing in the tissues [5].

The cells of a tissue, or tissues, in an organism are primed to respond when they are exposed to an unusual stimulus. The response leads to a set of consequences, such as eicosanoid, cytokine, chemokine release, alterations in metabolic activity and genes becoming activated or switched off. These events can cause further cell activation either intrinsically within the tissue or extrinsically such as drawing leukocytes into the tissue. The whole process would be described as an inflammatory response.

The sequelae to the initiating events can lead to an expansion of the response, or the challenge can be nullified and the tissues return to an original state. If the inflammatory state continues, it can either persist as a long-term process, encountered as chronic diseases, or in severe cases, the explosive changes overwhelm the organism leading to tissue necrosis and organ failure [6, 7].

There are reasonable arguments to suggest that normal ageing shares some similarities with such chronic inflammatory disease [8, 9]. Indeed, the term 'inflammaging' was coined to describe this possibility [9]. This case has also been made for specific diseases of ageing, such as osteoporosis [10, 11].

There is also an innate anti-inflammatory process involving leukocytes and a number of biological mediators, such as cytokines; however, with respect to vitamin K, this area of research has not been the subject of focused research.

Irrespective of how we currently define inflammation, it is a biological process that serves a purpose in the preservation of the organism, sometimes at the cost of some part of the whole, but the government of the system can all too easily slip free of controls [12].
