Central nervous system inflammation in disease related conditions: mechanistic prospects.

Inflammation is part of the innate immune response following insults to the body. This inflammatory reaction can spread throughout the systemic circulation and also into the central nervous system (CNS). CNS involvement has been demonstrated following acute peripheral insults including sepsis, surgery, burns and organ injury. It has also been observed in chronic conditions including obesity, diabetes and rheumatoid arthritis. Inflammation within the CNS is part of the pathogenesis of neurodegenerative diseases, in particular Alzheimer's disease, multiple sclerosis and Parkinson's disease. These diseases are prone to exacerbation as a result of increased inflammation within the CNS following peripheral insult. The effect of inflammation within the CNS can also be modulated by other factors including age and also oestrogen, although how pro-inflammatory cytokines within the CNS cause clinical changes remains to be elucidated. The mechanism underlying the passage of inflammation from the periphery into the CNS also remains unclear. Evidence has led to the suggestion of two main pathways: blood brain barrier (BBB) dependent and BBB independent. This uncertainty has led to an increasing body of work exploring the processes involved in both the passage of inflammation into, and the effect of cytokines on, the CNS.