Diabetes, Vol 39, Issue 8 909-913, Copyright © 1990 by American Diabetes Association
Relationship of endoneurial capillary abnormalities to type and severity of diabetic polyneuropathy
ST Britland, RJ Young, AK Sharma and BF Clarke
Department of Anatomy, Aberdeen University, United Kingdom.
Endoneurial capillary abnormalities have been assessed quantitatively in
sural nerve biopsies from diabetic patients with different syndromes of
sensory polyneuropathy: chronic painful neuropathy, newly presenting
painful neuropathy, and painless neuropathy associated with neurotrophic
foot ulceration. Comparisons were made with age-matched nondiabetic control
subjects. The diabetic groups showed no abnormality in capillary density or
mean endoneurial area per fascicle. Compared with control subjects, all
diabetic patients had an increase in mean capillary diameter, capillary
wall thickness, and outer tunic (basement membrane and pericytes)
thickness. The increase in wall thickness was most pronounced in patients
with painless neuropathy (200%) and less marked in similar patients with
painful neuropathy (100%). The pericyte volume fraction of the outer tunic
was reduced in all diabetic patients, implying that basement membrane
hypertrophy and reduplication were responsible for outer tunic thickening.
There was evidence of endothelial cell hyperplasia rather than hypertrophy.
There was a correlation between the degree of basement membrane thickening
and the severity of myelinated fiber abnormality assessed
neurophysiologically and morphologically. This study shows a link between
the degree of endoneurial capillary basement membrane thickening, the type
of neuropathology, and the clinical expression of neuropathy in diabetes
mellitus.