Because of their abnormal shape, prions (PrPRes/Sc) tend to stick to each other and, over time, stack up to form long chains called amyloid fibers. These aggregates of amyloid fibers contribute to the disruption of the normal tissue structure and aid in the causation of the neurodegenerative disease.
The fibers are exceedingly stable and are extremely resistant to denaturation by chemical agents (such as formalin), proteases, radiation, freezing, or other mediums damaging to nucleic acids. Several studies have shown that temperatures normally used for cooking or autoclaving are not effective decontaminants.
The central nervous system (CNS) consists of neurons and glial cells. Neurons make up about half of the volume of the CNS, and glial cells make up the rest. Glial cells are known as supporting cells that have four main functions:
- Supply nutrients and oxygen to neurons
- Insulate one neuron from another
- Hold neurons in place
- Remove dead neurons
The three types of glial cells are astrocytes, oligodendrocytes, and microglia. Astrocytes are characteristically star-shaped and are the most abundant cells of the human brain. Astrocytes crawl through the brain, digesting the dead neurons and leaving “holes” where the neurons used to be. This is what gives the tissue of the central nervous system that spongy look.
