A richer and more diverse future for microglia phenotypes.

Area of Science:

• Neuroscience
• Immunology
• Cell Biology

Background:

• Microglia are the primary innate immune cells in the central nervous system (CNS).
• They are crucial for CNS development, injury repair, and immune responses.
• Traditionally, microglia are classified as M0 (resting), M1 (pro-inflammatory), and M2 (anti-inflammatory/repair) phenotypes.

Purpose of the Study:

• To review the current consensus and controversies surrounding microglial polarization typing.
• To provide a basis for a more objective understanding of microglial functional phenotypes.
• To address the limitations of the M1/M2 polarization model.

Main Methods:

• Literature review of existing research on microglial polarization.
• Analysis of conflicting viewpoints on microglial phenotype classification.
• Discussion of the implications for understanding microglial function in health and disease.

Main Results:

• The traditional M1/M2 microglia polarization model is increasingly debated.
• Some researchers question the confirmation of distinct M1/M2 polarization phenomena.
• The M1/M2 classification is considered a simplification with inherent limitations.

Conclusions:

• A critical revision of the concept of microglial polarization is necessary.
• The diversity and complexity of microglial responses challenge simple M1/M2 categorization.
• Further research is needed to establish more accurate models of microglial functional states.