Wednesday, December 19, 2012

A fog of inflammation

Raise your hand if you know what a cytokine is.

Me neither.

A family member sent me this link and it kind of sounds too good to be true:
New hope for survivors of stroke and traumatic brain injury

I've been trying to understand what it means. The press release itself is clear enough. A new study shows that a single dose of a drug causes rapid clinical improvement long after brain injury. It seems to work in both TBI and stroke survivors. The drug is Etanercept, a biopharmaceutical that inhibits Tumor Necrosis Factor (TNF). TNF is a cytokine and cytokines help regulate your immune system.

Crystal structure of TNF
How can this be? A single dose of an immunosupressant improves motor impairment, spasticity, cognition, and other lingering impacts of brain injury. On average the TBI subjects were ~10 years post-injury. The stroke subjects were ~4 years post-injury.

Even if there's no miracle cure, lingering effects of brain injury have something to do with the immune system. The protective system that rushes to help at the time of injury ends up inhibiting the healing process.

In public high school, even though Mr. Gelatt was a great Biology teacher (as well as kind and funny), we didn't learn a thing about the immune system.

Found this article:
Traumatic Brain Injury and Inflammation: Emerging Role of Innate and Adaptive Immunity

After about the third pass through, I understood a lot more.

Our brains are usually protected from the antics of our immune systems by the blood-brain barrier (BBB). After a brain injury, the BBB opens twice; once immediately after the injury and again 3-7 days afterward. The second opening can last from days to years. All kinds of substances employed by your immune system reach the brain during this time. Some try to repair damage and reduce inflammation, while others encourage inflammation.

The article talks about the accidental impact white blood cells can have on your injured brain:
Leukocytes are believed to be important in the initiation and progression of inflammation following TBI because they contain and release a significant number of inflammatory mediators that injure neurons.
They think this might be why after repeated 'brain insults', there is a higher risk of Alzheimer's disease. The repeated immune response and inflammation in the brain seem to snowball.

Why don't we just go find some Etanercept (Enbrel)? Because if something seems too good to be true, then it probably is a scam!

Update: the San Francisco Chronicle, which no longer practices real journalism, fell for this. I would guess this content  is a paid placement by the Institute for Neurological Recovery, portrayed as a real article.

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