4-Hydroxynonenal as a second messenger of free radicals and growth modifying factor

Immunohistochemical analysis of the distribution of the lipid peroxidation product 4-hydroxynonenal (HNE) in the brain of baboons exposed to experimen tal hemorrhagic traumatic shock or sepsis showed that systemic oxidative st ress and the thereby generated HNE affect the blood:brain barrier and the r egulation of cerebral blood now determing secondary brain damage. Similarly , HNE was determined during ischemia in the brain blood vessels of rats exp osed to ischemia/reperfusion injury of the brain. After reperfusion, HNE di sappeared from the blood vessels but remained in neurones and in glial cell s. Since HNE modulates cell proliferation and differentiation (including pr oto-oncogene expression), it is postulated that HNE might have prominent lo cal and systemic effects that are not only harmful but beneficial too, dete rming the outcome of various pathophysiologcial conditions based on oxidati ve stress.