Alanine Aminopeptidase Activity in Urine: A New Marker of Chronic Alcohol Abuse?

Abstract

The results of this study demonstrate that the assays of urinary AAP activity, which relate to the nephrotoxic effects of alcohol abuse, could be a valuable complement to the other presently used markers of chronic alcohol abuse that are generally based on ethanol hepatotoxicity. Compared with the uAAP activity test, the eAAP activity test is of clear diagnostic advantage.

Combining markers of nephrotoxicity and hepatotoxicity for improved monitoring and detection of chronic alcohol abuse

“…Moreover, the AUC was only negligibly greater for eHex than for uHex (one-tailed significance level, ps0.24), whereas it was significantly greater for eAAP than for uAAP (ps0.021). These results showed no substantial benefit from the Sephadex filtration step for the Hex assay, while the reverse was true for the AAP assay wsee also Taracha et al (24)x. Therefore, we decided to omit the eHex and uAAP results in further data analyses.…”

“…We have recently reported that uAAP is a good marker of chronic alcohol abuse, particularly after removing its endogenous inhibitors (24). While uncommon in clinical practice, uHex also has been Brought to you by | University of Arizona Authenticated Download Date | 6/5/15 8:35 PM Table 3 Diagnostic accuracy of the proposed compound marker G&Hs0.62=ln(GGT)q0.72=ln(uHex) and its component markers.…”

“…These groups did not differ significantly in addiction duration (results presented as range, median and mean"SD) The patients constituted most of the cohort for which the utility of AAP as a marker of alcohol abuse was reported earlier (24). None of the patients was being treated for a liver or kidney disease or suffered from alcohol-dependent liver cirrhosis.…”

“…As freezing of urine can markedly decrease AAP activity, but not Hex activity w (29,30); unpublished data from this laboratoryx, the samples were stored for up to 3 days at q48C before analysis, but were never frozen. Hex and AAP Brought to you by | University of Arizona Authenticated Download Date | 6/5/15 8:35 PM IU/L, in serum; b arb.u./mmol urine creatinine, in native urine (uHex, uAAP) or Sephadex urine eluate (eHex, eAAP); c most of the individual data for calculating uAAP and eAAP mean"SD values were taken from our earlier study (24). *p-10 y5 vs. the abstinent group, Mann-Whitney U-test; † p-10 y6 vs. the enzyme activity in native urine, Wilcoxon signed rank test.…”

“…Hence, alcohol abuse-related elevation of urinary activity of Hex and AAP represents a potential tool for non-invasive diagnosis of such abuse. There is a slowly growing body of evidence showing the potential clinical utility of urinary markers in diagnosing and monitoring alcohol abuse (20,21,23,24).…”