An Improved Neutral a-Glucosidase Assay for Assessment of Epididymal Function—Validation and Comparison to the WHO Method

Abstract

Neutral α-glucosidase (NAG) activity in human seminal plasma is an important indicator for epididymis functionality. In the present study, the classic World Health Organization (WHO) method has been adapted to enhance assay robustness. Changes include modified enzyme reaction buffer composition and usage of an alternative enzyme inhibitor for background correction (glucose instead of castanospermine). Both methods have been tested in parallel on 144 semen samples, obtained from 94 patients/donors and 50 vasectomized men (negative control), respectively. Passing-Bablok regression analysis demonstrated equal assay performance. In terms of assay validation, analytical specificity, detection limit, measuring range, precision, and cut-off values have been calculated. These data confirm that the adapted method is a reliable, improved tool for NAG analysis in human semen.

Human and animal fertility studies in cystinosis reveal signs of obstructive azoospermia, an altered blood‐testis barrier and a subtherapeutic effect of cysteamine in testis

“…These data suggest a subtherapeutic effect of cysteamine treatment at the testicular level. Interestingly, our observations are in line with the previously suggested role of inflammation in the pathogenesis of cystinotic kidney disease, in which similar to infertility, the phenotype cannot be cured by cysteamine 27,29‐31 31 .…”

“…Interestingly, our observations are in line with the previously suggested role of inflammation in the pathogenesis of cystinotic kidney disease, in which similar to infertility, the phenotype cannot be cured by cysteamine. 27,[29][30][31] Macrophages are known to secrete F I G U R E 4 Effect of oral cysteamine on fertility in wild type and Ctns knockout male mice. Panel (A): Overview of the pre-clinical animal study design.…”

Seminal Plasma Analysis of Oxidative Stress in Different Genitourinary Topographical Regions Involved in Reproductive Tract Disorders Associated with Genital Heat Stress

“…An improved NAG assay with the usage of glucose as an enzyme inhibitor for background correction was performed [ 60 ]. The principle of the test was based on the conversion of 4-nitrophenyl-α-D-glucopyranoside into 4-nitrophenol and α-D-glucopyranoside.…”

A novel laboratory procedure to validate American Urological Association guideline on vasectomy success and to diagnose obstructive azoospermia

“…The NAG assay as described in World Health Organization laboratory manual (2010) as well as improved reaction buffer composition and inhibitor type (Eertmanset et al, 2014) is not routinely used, probably because the results are somewhat ambiguous due to the activity of nonspecific glucosidase at pH 6.8. However, calculating the differences in the relative NAG activity between two time points of incubation time during the modified assay appears eliminate the observed ambiguity of the results.…”