Urinary steroidomic profiles by LC-MS/MS to monitor classic 21-Hydroxylase deficiency

Abstract

21-hydroxylase deficiency, the most common enzyme defect associated with congenital adrenal hyperplasia (CAH) is characterized by an impairment of both aldosterone and cortisol biosynthesis. Close clinical and biological monitoring of Hydrocortisone (HC) and 9α-Fludrocortisone (FDR) replacement therapies is required to achieve an optimal treatment. As frequent and repeated reassessments of plasma steroids, 17-hydroxyprogesterone (17-OHP), androstenedione (Δ4-A) and testosterone (TESTO) is needed in childhood, urine steroid profiling could represent an interesting non-invasive alternative. We developed and validated a LC-MS/MS method for the measurement of 23-urinary mineralocorticoids, glucocorticoids and adrenal androgens. The usefulness of steroid profiling was investigated on single 08h00 am-collected spot urine for discriminating between 61 CAH patients and their age- and sex-matched controls. CAH patients were split into two groups according to their 08h00 am-plasma concentrations of 17-OHP: below (controlled patients, n = 26) and above 20 ng/mL (uncontrolled patients, n = 35). The lower limit of quantification and the wide analytical range allows to assay both free and total concentrations of the main urinary adreno-corticoids and their tetra-hydrometabolites. Extraction recoveries higher than 75% and intra-assay precision below 20% were found for most steroids. Urinary steroids upstream of the 21-hydroxylase defect were higher in uncontrolled CAH patients. Among CAH patients, plasma and urinary 17-OHP were closely correlated. As compared to controls, steroids downstream of the enzyme defect collapsed in CAH patients. This fall was more pronounced in controlled than in uncontrolled patients. Androgens (Δ4-A, TESTO and the sum etiocholanolone + androsterone) accumulated in uncontrolled CAH patients. A strong relationship was observed between plasma and urinary levels of androstenedione. Daily doses and urinary excretion of both FDR and HC were similar in both CAH groups. Urinary FDR was inversely related to the sodium-to-potassium ratio in urine. A partial least squares discriminant analysis model allowed to classify the patient's classes unaffected, controlled and un-controlled CAH patients based on urinary steroidomic profiles. Our LC-MS/MS method successfully established steroid profiling in urine and represents a useful and non-invasive tool for discriminating CAH patients according to treatment efficiency.

Keywords: Congenital adrenal hyperplasia; Fludrocortisone; Hydrocortisone; LC-MS/MS; Replacement therapy monitoring; Urinary steroidomic profile.