We studied the immunolocalization of Dp116 (a 116 kDa
protein product of the
dystrophin gene),
vinculin,
talin,
vimentin,
desmin,
spectrin and
titin in the sural nerve biopsies of 25 patients with
peripheral neuropathies of different origin. 4 patients presented with
HMSN type 1, 4 with
HMSN type 2, 2 with HNPP, 4 with
CIDP, 5 with chronic axonal neuropathy of unknown origin, 3 with vasculitic neuropathy, 3 with
diabetic neuropathy. Expression and localization of Dp116,
vinculin,
vimentin,
desmin,
spectrin and
titin did not differ from normal control cases.
Spectrin and
titin immunoreactivities were absent and
desmin was occasionally found in few epineurial vessels. A thin rim of Dp116 binding surrounded the outermost layer of myelin sheaths. Perineurium and epineurial vessels stained deeply for
vinculin.
Vimentin immunoreactivity was seen in all endoneurial, perineurial and epineurial cells. Immunoreactivity for
talin was normally found at endoneurial and epineurial vessel walls, perineurial cells and epineurial fibroblasts in all the sural nerves except diabetic nerves. In the latter, whereas
talin binding was normal in the vessel walls and epineurial fibroblasts, it was markedly reduced in the perineurium. On immunoblot, two bands at 235 and 190 kDa were found in the sural nerves with the antibody anti-
talin, and both were reduced only in the patients with
diabetic neuropathy. We postulate that decreased perineurium
talin in
diabetic polyneuropathy may be related to the known alterations of the tight junctions of the perineurial cells, which have been proposed to be a contributory factor to impaired permeability barrier properties.