Serum N-acetyl-beta-glucosaminidase Activity in Diabetic Patients

Abstract

In a group of seventy-three diabetics, a statistically significant (P < 0.001) increase (+ 41 per cent) of serum N-acetyl-beta-glucosaminidase activity was found. The enzyme level seemed to correlate with both the vascular complications (either microangiopathic or macroangiopathic in nature) and the blood sugar level measured simultaneously. In fact, in patients with moderately elevated glycemia (145 mg./100 ml. ± 41) and without vasculopathies, the enzymatic activity was slightly changed (P > 0.05), while the activity was significantly (P < 0.001) increased (+ 31 per cent), in diabetics with essentially similar gly-cemia (151 mg./100 ml. ± 30) but with vasculopathies, and even more elevated (+ 80 per cent, P < 0.001) in diabetics without vasculopathies but with marked hyper-glycemia (309 mg./100 ml. ± 160). Since lysosomal enzymes, to which N-acetyl-beta-glucosaminidase belongs, are capable of degrading various compounds, these enzymatic changes were regarded as due to an activation of lysosomal enzymes in tissues, occurring in diabetes in response to the metabolic need of degrading either mucopolysaccharides and glycoproteins (as in diabetics with vasculopathies), or various constituents of cells themselves in a context of increased tissue catabolism (as in decompensated diabetics). However, the possibility cannot be excluded that the enzyme is elevated merely because of decreased lysosome stability. Reduction in the destruction rate of the enzyme might also contribute to its elevation.

?-N-acetylglucosaminidase and ?-glucuronidase activities in insulin-dependent diabetic subjects with retinopathy

“…The present results are in accordance with those of earlier studies, which have shown an elevation of serum GLU [4,8,25] and NAG [2,6,11,25] in patients with diabetes mellitus. Further, in the present study the levels of the two lysosomal enzymes in the diabetics were significantly higher in subjects with non-proliferative retinopathy (p < 0.05 for both enzymes).…”

“…Very high enzyme levels have been encountered in diabetics with a severely deranged metabolic balance [2,4,10]. Although a similar correlation was also detected in the present study, all of the patients were clinically in fairly good glycaemic control and the blood glucose level was similar in the groups with and without non-proliferative retinopathy.…”

“…Further, in the present study the levels of the two lysosomal enzymes in the diabetics were significantly higher in subjects with non-proliferative retinopathy (p < 0.05 for both enzymes). In previous studies an association has been reported between serum GLU [4] and NAG [2] and the presence of microangiopathy and large vessel lesions in diabetic subjects, and also between serum NAG level and retinopathy [11].…”

“…, 25] and a close correlation between the enzyme activities and the blood glucose level of diabetics has been documented [2,4,5,25]. The serum lysosomal enzyme changes may also be associated with the pathogenesis of microangiopathy [2,4,11], although the relation is not yet clear and more data are needed.…”

“…The serum lysosomal enzyme changes may also be associated with the pathogenesis of microangiopathy [2,4,11], although the relation is not yet clear and more data are needed. In the present study, serum NAG and GLU have been determined in patients with insulin-dependent diabetes of long duration and with different degrees of diabetic retinopathy and the levels compared with those in two, non-diabetic reference groups of subjects.…”