Increased endoneurial albumin in diabetic polyneuropathy.

Albumin was measured in the endoneurium of fascicular biopsies of sural nerves and in plasma from diabetic patients with polyneuropathy by solid phase radioimmunoassay, and normalized to total endoneurial and plasma protein, respectively, to obtain an index of the blood-nerve barrier (BNB-Index). Fifteen diabetic patients with polyneuropathy had a mean BNB-Index of 29.7 +/- 12.6% SD, 3.8 times higher than control values (7.8 +/- 2.0% SD, n = 4). These data suggest that the blood-nerve barrier of endoneurial capillaries is impaired in patients with diabetic polyneuropathy.