Thursday, March 1, 2007

'Aging, Brain Inflammation and Behavior'

Thought this was interesting in relation to DS, although he doesn't mention it. Alot of people with DS have weak immune systems, which leads to being sick alot, at times. This could have something to do with their cognition. We already know that inflammation is an issue with people with DS. I've emailed the professor who talks about this and asked him for the name of the study which is being talked about below.

Professor presents 'Aging, Brain Inflammation and Behavior'

Kristi Kawanna

Rodney Johnson presented a seminar "Aging Brain Inflammation and Behavior" on Feb. 2. Hosting the seminar was the department of biological sciences and Phi Sigma.Johnson came to ISU from the University of Illinois, where he is an integrative immunology and behavior professor. Johnson has also authored over 78 publications. "It is interesting to think about the interaction between the immune system and the brain. Ten years ago people may not have even thought there was such an interaction, but today that is not the case. Remember that the brain does not have a way to detect infection pathogens, but when we are sick we change our behavior, motivating us to act differently than when we are well. I call this the sickness behavior syndrome," Johnson said. After a brief introduction of his study, Johnson began to explain the basis of his research. "You begin with an infectious pathogen. A macrophage encounters the infection and produces inflammatory cytokines in the brain. These cytokines cause behavior response," Johnson said. Behavior responses include food intake, spatial working memory deficits, slow wave sleep, lethargy, cognitive and motor deficits, depression, decreased social behavior and anorexia. Johnson then discussed the importance of Lipopolysaccharide and sickness behavior. Part of the research Johnson has done to understand this concept, has been performed on older rats. A rat injected with increased LPS showed a difference in behavior than a rat that wasn't affected by the LPS. Johnson explained the brain forms a representation of the peripheral innate immune system response. The representation is at the origin of sickness behavior and is cytokine based. "It's important to keep in mind that sickness behavior is normally adaptive and fully reversible. Georges Canguilhem once said 'To be healthy is to be able to be ill and recover from it.' Sickness behavior is a normal part of life," Johnson said. Johnson also discussed the fact that ongoing brain pathology "primes" microglia (primary stimulus) and that peripheral infection further activates microglia (secondary stimulus). This information is used in studying diseases such as Multiple Sclerosis and Alzheimer's disease. Also discussed at the seminar were the effects LPS and cytokines have on the elderly. "We need to understand what makes some individuals not recover completely when they get well. This is especially true of the elderly. An infection in an elderly person can lead to cognitive impairment. This then leads to diminished self care such as weight loss, anorexia and the fact that they will be less likely to visit an out-patient clinic. Once self-care begins to diminish, more hospitalization is needed and the mortality rate goes up," Johnson said.
At the end of the seminar, guests were encouraged to ask questions. The topics of inflammatory drugs in relation to fevers and whether or not inflammation and depression are related were discussed. "In regards to whether or not inflammatory drugs should be taken to reduce fever is a topic that is being looked at carefully in the medical world. I was surprised last year when I came across an article by the American Nurses Association that discussed the benefits of fever. As long as a fever isn't too high, inflammatory drugs aren't always needed as long as the fever is monitored," Johnson said. "There is a strong link between inflammation of the brain and depression. Anytime there is an increase in inflammation, there can be a disruption in serotonin, which can lead to higher levels of depression," Johnson said. Johnson also said anytime there is tissue trauma, inflammation is the response, which can lead to post surgical cognitive disorder. "I thought the seminar was very interesting. Everything was new information to me, but it made sense. Johnson was a good speaker who kept the information entertaining. He also brought the information down to a basic level so it was easier to understand," Kelly Slattery, biology graduate student, said.

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