Lysosomal enzymes in preterm infants with bronchopulmonary dysplasia: a potential diagnostic marker

Some lysosomal glycohydrolases (N-acetyl-beta-D-glucosaminidase and their m ajor isoenzymes, beta-D-glucuronidase, alpha-D-galactosidase, beta-D-galact osidase and alpha-D-glucosidase) were investigated in the plasma of 36 pret erm infants with respiratory distress, 11 of whom developed bronchopulmonar y dysplasia (BPD), in order to evaluate the role of the lysosomal apparatus in the disease. Enzyme activity was assayed fluorimetrically; the major N- acetyl-beta-D-glucosaminidase (NAG) isoenzymes were separated using a routi ne chromatofocusing procedure; the diagnostic efficiency was evaluated by B ayes theorem. The mean levels of almost all glycohydrolases considered were significantly higher in BPD than in non-BPD infants. Among NAG major isoen zymes, an increase was found only in form A. No variation was evident in th e plasma levels of glycohydrolases during dexamethasone therapy. Data from a retrospective analysis performed in all preterms considered, show that al pha-D-galactosidase and beta-D-galactosidase differentiate a posteriori BPD and non-BPD subjects. These enzymes, after a priori verification of their diagnostic potential in preterm infants at risk of BPD development, could a cquire an important predictive value. (C) 1998 Elsevier Science B.V. All ri ghts reserved.