✍️ Author: Dr Eleni Christoforidou
🕒 Approximate reading time: 4 minutes
For years, the brain was believed to function as an immunologically privileged site, largely isolated from the immune system. However, recent research has unveiled intricate interactions between the immune system and the brain, bringing to light potential connections to neurodegenerative diseases. This article endeavours to shed light on this ever-evolving field.
Microglia are the resident immune cells of the brain. Under normal conditions, they patrol the neural environment, clearing away debris and dead cells. But in the context of neurodegeneration:
They can become overactive, releasing inflammatory molecules that can damage neurons.
Some genetic variants associated with neurodegenerative diseases, such as Alzheimer's, can affect microglial function, highlighting their potential role in disease progression.
The blood-brain barrier (BBB) largely shields the brain from the peripheral immune system. However, breaches or changes in the BBB's permeability, often seen in neurodegenerative diseases, can allow peripheral immune cells to enter the brain, potentially exacerbating inflammation and damage.
Chronic inflammation is now recognised as a common thread among various neurodegenerative diseases. While acute inflammation can be protective, chronic inflammation might promote neuronal damage. Factors include:
Some neurodegenerative diseases might have autoimmune components, where the immune system mistakenly targets brain tissues. For instance, in multiple sclerosis, the immune system attacks myelin, leading to progressive neurodegeneration.
Understanding the immune system's role in neurodegeneration has opened doors to potential therapies:
The intricate dance between the immune system and the brain offers both challenges and opportunities. As we delve deeper into this relationship, the prospects of harnessing the immune system for therapeutic benefit in neurodegenerative diseases become increasingly tantalising.