Quantification of sweat gland innervation: a clinical-pathologic correlation

Area of Science:

• Neurology
• Dermatology
• Pathology

Background:

• Diabetic neuropathy affects small nerve fibers, including those innervating sweat glands.
• Quantifying sweat gland nerve fiber density (SGNFD) is crucial for diagnosing sudomotor dysfunction.
• Existing methods for SGNFD quantification can be labor-intensive and lack standardization.

Purpose of the Study:

• To introduce and validate a novel manual morphometry method for quantifying SGNFD.
• To compare the novel method against unbiased stereologic quantification.
• To assess the relationship between SGNFD, neuropathy severity, and patient-reported symptoms.

Main Methods:

• Skin biopsies were obtained from diabetic and healthy subjects.
• Nerve fibers innervating sweat glands were stained and imaged using light microscopy.
• SGNFD was quantified via manual morphometry and validated against confocal microscopy with stereology.

Main Results:

• Manual morphometry showed high correlation with unbiased stereology (r=0.93).
• Diabetic subjects exhibited significantly reduced SGNFD compared to controls across multiple body sites.
• Reduced SGNFD correlated with increased neuropathy impairment scores and reduced sweat production symptoms.

Conclusions:

• A novel, reliable method for quantifying SGNFD has been developed.
• This technique effectively distinguishes diabetic neuropathy from healthy controls.
• SGNFD measurement serves as a valuable structural biomarker for small fiber neuropathies and sudomotor dysfunction.