Microglial process convergence onto injured axonal swellings, a human postmortem brain tissue study

Area of Science:

• Neuroscience
• Neuropathology
• Neuroinflammation

Background:

• Traumatic brain injury (TBI) affects millions globally, with mild TBI often involving diffuse axonal injury and microglial activation.
• Microglial process convergence (MPC), where microglia contact injured axons, has been observed in pigs but not rats post-TBI.
• The interaction between microglia and injured axons in human TBI, specifically MPC, remains poorly understood.

Purpose of the Study:

• To investigate and quantify microglial process convergence (MPC) onto injured axons in human postmortem brain tissue following TBI.
• To validate previous findings of MPC in micropigs using human samples.
• To assess the clinical relevance of MPC as a neuroinflammatory phenomenon in human TBI.

Main Methods:

• Utilized multiplex immunofluorescent histochemistry on human postmortem brain tissue.
• Examined cases from individuals with TBI and control subjects.
• Quantitatively measured MPC onto injured axonal swellings and intact myelinated fibers.

Main Results:

• Observed a significant increase in microglial process convergence (MPC) onto injured axonal swellings in human TBI cases.
• Findings are consistent with previous observations in micropigs following diffuse TBI.
• Demonstrated that MPC occurs in the human brain following TBI.

Conclusions:

• Microglial process convergence (MPC) is a relevant phenomenon in human traumatic brain injury (TBI).
• MPC occurs on injured axonal swellings in the human brain post-TBI.
• Further investigation into MPC's role in human TBI pathogenesis is warranted.