ε-Amino-Lysine-Bound Glucose in Human Tissues Obtained at Autopsy: Increase in Diabetes Mellitus

Abstract

The level of nonenzymatically ε-lysine-bound glucose (NEBG) of tissue proteins obtained at autopsy has been determined with a specific method recently described.5 The mean values expressed as nmol lysine-bound glucose per μmol phenylalanine were 34 for tendon, 13 for aorta, 16 for coronary artery, 23.5 for femoral nerve, 10 for glomerular basement membrane, and 30 for lung parenchyma for tissues from nondia-betics and 86, 39.5, 34, 60, 29, and 57 for tissues from diabetics, respectively. NEBG was below detection limit in skeletal muscle from either nondiabetic or diabetic subjects. Tendon and aorta NEBG levels correlated well with those from other tissues (r = 0.8=0.94, except r = 0.68 for glomerular basement membrane). A fairly good correlation was also found when NEBG of aorta was compared with the mean blood sugar level determined during the last weeks of hospitalization. Finally, an arbitrary index of diabetic late complication was compared with NEBG of aorta. There appears to be a tendency of an increase of the index of complications along with an increase in tissue glucosylation. The possible role of nonenzymatic glucosylation in the long-term complication of diabetes is discussed.