Axonal swellings in human intramuscular nerves

Area of Science:

• Neuropathology
• Neuroscience
• Muscle Biology

Background:

• Axonal swellings represent a pathological finding in peripheral nerves.
• Their presence, composition, and implications in various neuromuscular diseases are not fully understood.

Purpose of the Study:

• To evaluate the presence, morphology, distribution, and abundance of axonal swellings in intramuscular nerves.
• To investigate the association of axonal swellings with different neuromuscular conditions.

Main Methods:

• Analysis of 127 muscle biopsies.
• Histological examination of intramuscular nerves to identify and characterize axonal swellings.
• Morphometric analysis of swelling size and location.

Main Results:

• Axonal swellings were identified in 42% of muscle biopsies.
• Highest incidence observed in peripheral neuropathy, particularly chronic inflammatory demyelinating neuropathy.
• Swellings were spherical/elliptical, neurofilament-rich, located in myelinated axons, and not linked to degeneration.
• Present in various conditions, including motor neuron disease, primary muscle diseases, and even in some healthy individuals.

Conclusions:

• Axonal swellings are a common finding in intramuscular nerves across diverse conditions.
• Their presence suggests altered axonal dynamics rather than degeneration.
• Further research is needed to elucidate the precise mechanisms and clinical significance.