Evaluation of small nerve fiber dysfunction in type 2 diabetes

Area of Science:

• Neurology
• Histopathology
• Diabetology

Background:

• Peripheral neuropathy is a common complication of diabetes.
• Assessing small nerve fibers in the skin is crucial for diagnosis.
• Limited data exists on the correlation between intraepidermal nerve fiber density (IENFD) and clinical neuropathy measures in different glucose tolerance groups.

Purpose of the Study:

• To investigate the relationship between intraepidermal nerve fiber density (IENFD) and clinical neuropathy assessments.
• To compare IENFD across elderly men with normal glucose tolerance (NGT), impaired glucose tolerance (IGT), and type 2 diabetes (T2DM).

Main Methods:

• Skin biopsies from the distal leg of 86 men (71-77 years) were analyzed for IENFD using immunohistochemistry (PGP 9.5).
• IENFD was correlated with neurophysiological tests (nerve conduction study, quantitative sensory testing) and clinical scores (Total Neuropathy Score).

Main Results:

• Absent intraepidermal nerve fibers (IENF) were observed in 21% of T2DM and 7% of IGT subjects.
• IENFD showed weak negative correlations with HbA1c and Total Neuropathy Score.
• Positive correlations were found between IENFD and sural nerve amplitude and conduction velocity.

Conclusions:

• Decreasing IENFD is associated with a higher prevalence of neuropathy signs.
• The presented technique for evaluating IENFD in histopathological sections is valuable for neuropathy detection.