The Rogue Immune Cells That Wreck the Brain

[Remy]

The microglia seem to be very important but are just beginning to be studied in general.

Cort has written a couple of articles on this topic as well that contain info on how the microglia are thought to influence symptoms of MECFS...mostly from talks done by Dr Jared Younger.

http://www.healthrising.org/blog/20...-fibromyalgia-chronic-fatigue-syndrome-mecfs/

But this is a really good article too.

In the first years of her career in brain research, Beth Stevens thought of microglia with annoyance if she thought of them at all. When she gazed into a microscope and saw these ubiquitous cells with their spidery tentacles, she did what most neuroscientists had been doing for generations: she looked right past them and focused on the rest of the brain tissue, just as you might look through specks of dirt on a windshield.

“What are they doing there?” she thought. “They’re in the way.’”

Stevens never would have guessed that just a few years later, she would be running a laboratory at Harvard and Boston’s Children’s Hospital devoted to the study of these obscure little clumps. Or that she would be arguing in the world’s top scientific journals that microglia might hold the key to understanding not just normal brain development but also what causes Alzheimer’s, Huntington’s, autism, schizophrenia, and other intractable brain disorders.

Microglia are part of a larger class of cells—known collectively as glia—that carry out an array of functions in the brain, guiding its development and serving as its immune system by gobbling up diseased or damaged cells and carting away debris. Along with her frequent collaborator and mentor, Stanford biologist Ben Barres, and a growing cadre of other scientists, Stevens, 45, is showing that these long-overlooked cells are more than mere support workers for the neurons they surround. Her work has raised a provocative suggestion: that brain disorders could somehow be triggered by our own bodily defenses gone bad.

[bimg=no-lightbox]https://www.technologyreview.com/i/images/glia34.jpg?sw=590&cx=0&cy=0&cw=2106&ch=2106[/bimg]

 

[Paw]

This recent New Yorker piece focuses mostly on schizophrenia, but does a great job of summarizing (and simplifying) the current state of microglia research.

And, surprise, surprise -- the immune system is key. Immune-system proteins are supposed to "tag" bad cells for elimination, and then the microglia (roving around like tiny Roombas) "prune" the identified waste. If the tagging process is screwed up, the microglia don't prune things properly. Germs that should be eliminated are left alone, as are "junk" synapses, bacterial remnants, cellular waste, etc.

Different disease conditions (according to the theory) are caused by varying malfunctions. Schizophrenia, for example, is thought to be the result of overly-pruned synapses (that's why schizophrenics have fewer neuronal connections), while, perhaps, autism is the result of under-pruning (too many overgrown connections diminish the capacity for adaptive learning).

What fascinates me most about all this research is that it can help explain (and synthesize) a hell of a lot of competing theories. Genetic variations in immune-system genes can lead to a multitude of variations in how the brain/body responds to viruses, stress, injury, etc. And the future of treatment -- whether for physiological or psychiatric symptoms -- may lie with medicines that very selectively prune the neural synapses. "Neurological landscaping."

And here's something fun: I read somewhere recently that hallucinogens (LSD, ayahuasca, etc) "complete the brain," returning it to some sort of primal state -- which is perfectly in keeping with the microglia theories! Infants have an overabundance of synaptic connections. The process of growing up, organizing knowledge, and establishing identities occurs in tandem with the process of microglial gardening. Brain scans show that hallucinogens temporarily reestablish those connections, so our minds revert to something similar to ego-less infancy.