What is the role of microglial cells and why are they so important in the CNS? What would happen if they either disappeared or decreased in number rapidly (can this happen in a healthy person—why)? What would happen if they became cancerous and replicated rapidly?
The role of microglial cells is to restore the homeostasis after CNS damages and to control the CNS environment. Hence, microglial cells are considered the primary immune effector cells or specialized resident macrophages and they represent 12% of the cells in CNS.
Microglial cells are activated, through receptors, by pathogens, endogenous toxins, viruses and degenerated neurons. While activated microglial cells help the brain to return to a normal condition by producing trophic factors, they also produce cytokines and neurotoxins that damage the neurons.
The permanent activation of microglia leads to neurodegenerative disorders like Parkinson's disease, Alzheimer's disease, HIV encephalopathy.
It is proved that brain microglia cells have a major contribution in brain tumors, mainly in astrocytic gliomas, since they are crucial transporters of epithelial cancer cells, fastening the colonization of brain with epithelial cancer cells and leading to metastasis formation.