title: Comparison of urinary excretion of four lysosomal hydrolases in healthy elderly and young adults.
abstract: The activities of four lysosomal enzymes and creatinine levels were measured in the plasma and urine of 17 healthy elderly and 7 young adults. Fractional enzyme excretion (FE ENZ) values for beta-hexosaminidase (N-acetylglucosaminidase), alpha-galactosidase, beta-galactosidase and beta-glucuronidase were calculated and compared between the two groups of subjects. FE ENZ was calculated as the ratio of enzyme clearance to creatinine clearance. The FE ENZ values for alpha-galactosidase, beta-galactosidase and beta-glucuronidase between the elderly and young populations were not statistically different; however, relative to the young control group, the FE ENZ value for beta-hexosaminidase was elevated approximately 2-fold in the elderly population (P = 0.06). The mean urinary alpha-galactosidase activity for the elderly population, when expressed on the basis of creatinine, was 50% lower than that of the control group (P = 0.03), whereas the mean urinary beta-hexosaminidase activity for the elderly was significantly higher compared to the control group (P = 0.008). When data for all subjects was analyzed, no correlation was observed between the urinary excretion of beta-hexosaminidase or alpha-galactosidase and glomerular filtration rate. These data indicate that with advancing age there are changes in the tubular secretion or reabsorption of selective lysosomal enzymes, particularly beta-hexosaminidase and alpha-galactosidase. These biochemical changes may provide a means of assessing subtle progressive deterioration of renal function.
authors.affiliation: Department of Biochemistry, University of New Mexico School of Medicine, Albuquerque 87131.
authors.forename: D J
authors.initials: DJ
authors.lastname: VanderJagt
authors.forename: B R
authors.initials: BR
authors.lastname: Steinberg
authors.forename: R H
authors.initials: RH
authors.lastname: Glew
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000652:urine*; D003404:Creatinine / Q000652:urine; D005260:Female; D005919:Glomerular Filtration Rate; D005966:Glucuronidase / Q000652:urine; D006801:Humans; D006867:Hydrolases / Q000652:urine*; D007668:Kidney / Q000502:physiology; D008247:Lysosomes / Q000201:enzymology*; D008297:Male; D000519:alpha-Galactosidase / Q000652:urine; D001616:beta-Galactosidase / Q000652:urine; D001619:beta-N-Acetylhexosaminidases / Q000652:urine
chemical_list: D003404:Creatinine; D006867:Hydrolases; D000519:alpha-Galactosidase; D001616:beta-Galactosidase; D005966:Glucuronidase; D001619:beta-N-Acetylhexosaminidases