From the Guidelines
Wallerian degeneration can be seen in peripheral nerve diseases such as Guillain-Barré syndrome, traumatic nerve injuries, diabetic neuropathy, and chronic inflammatory demyelinating polyneuropathy (CIDP), as these conditions involve axonal injury or transection. The process of Wallerian degeneration is a systematic degeneration of the distal portion of the axon separated from the cell body, which includes fragmentation of the axon and myelin sheath, followed by clearance of debris by macrophages and Schwann cells 1. According to a study published in Nature Reviews Neurology in 2019, Guillain-Barré syndrome is a rare, but potentially fatal, immune-mediated disease of the peripheral nerves and nerve roots that can cause Wallerian degeneration 1. Key characteristics of Wallerian degeneration include:
- Fragmentation of the axon and myelin sheath
- Clearance of debris by macrophages and Schwann cells
- Proliferation of Schwann cells to form bands of Büngner, which guide regenerating axons
- Correlation of severity and extent with the degree of axonal damage
- Visualization through nerve conduction studies, electromyography, or histological examination of affected nerves Understanding Wallerian degeneration is crucial for predicting recovery potential and determining appropriate treatment strategies for peripheral nerve injuries, as it can inform the likelihood of incomplete recovery and guide electrodiagnostic testing 1.
From the Research
Peripheral Nerve Diseases with Wallerian Degeneration
The following peripheral nerve diseases can exhibit Wallerian degeneration:
- Guillain-Barré syndrome, which is characterized by immune-mediated damage to the peripheral nervous system, leading to demyelination and axonal degeneration 2, 3
- Chronic inflammatory demyelinating polyneuropathy (CIDP), a condition that involves immune-mediated damage to the peripheral nerves, resulting in demyelination and axonal loss 2, 3
- Other degenerative, metabolic, heritable, toxic, inflammatory, and ischemic disorders that affect the peripheral nervous system 4
Characteristics of Wallerian Degeneration
Wallerian degeneration is a cascade of events that occurs in response to nerve fiber injury, involving:
- Cellular and molecular alterations, including macrophage invasion and activation of Schwann cells 5
- Elaboration of neurotrophins, which can influence the success or failure of subsequent regeneration 4
- Upregulation of cytokines and chemokines, which can have both beneficial and detrimental effects on nerve regeneration and neuropathic pain induction 5
Relationship between Wallerian Degeneration and Nerve Regeneration
Wallerian degeneration can set the stage for nerve regeneration, and manipulations of this process are being investigated as a potential means of altering the outcome of nerve regeneration 4, 6
- The discovery of genetic mutations that delay Wallerian degeneration has provided insight into mechanisms underlying axon degeneration in disease 6
- Understanding the molecular interactions between the immune system and peripheral nerve injury can open up possibilities for targeting inflammatory mediators in therapeutic interventions 5