cytellin and Xanthomatosis--Cerebrotendinous

Topics: Cholestanol; Cholesterol; Gas Chromatography-Mass Spectrometry; Humans; Hypercholesterolemia; Intestinal Diseases; Limit of Detection; Lipid Metabolism, Inborn Errors; Phytosterols; Reference Standards; Sitosterols; Xanthomatosis, Cerebrotendinous

Cerebrotendinous xanthomatosis (CTX) is an inborn error of bile acid synthesis in which hepatic conversion of cholesterol to cholic and chenodeoxycholic acids is impaired. Patients have abnormal bile alcohols in urine, normal to increased plasma cholesterol concentrations and increased concentrations of plasma cholestanol. Little is known about cholesterol precursors in CTX, however. We studied cholesterol and phytosterol profiles in two siblings with CTX during follow-up. While cholesterol concentrations were low in both patients, plasma cholestanol was 6-fold higher compared to control values. In addition, both siblings had a more than 100-fold increase in 7-dehydrocholesterol (7DHC) and 8-dehydrocholesterol (8DHC). Lathosterol, lanosterol and sitosterol were increased in both patients while concentrations of desmosterol and campesterol were normal. In addition, plasma lathosterol/cholesterol ratios were significantly elevated. After treatment with chenodeoxycholate, both patients showed a marked decrease in cholestanol, 7DHC, 8DHC, lathosterol, lanosterol and sitosterol. In addition, the lathosterol/cholesterol ratio normalized, indicating that overall cholesterol synthesis was sufficiently suppressed. This study shows that elevated cholesterol precursors, other than cholestanol, can be a hallmark for CTX.

Topics: Biomarkers; Chenodeoxycholic Acid; Child; Child, Preschool; Cholestadienols; Cholestanol; Cholesterol; Dehydrocholesterols; Humans; Lanosterol; Male; Predictive Value of Tests; Sitosterols; Time Factors; Treatment Outcome; Up-Regulation; Xanthomatosis, Cerebrotendinous

We have developed a highly sensitive and specific method for the analysis of serum sterol profiles. Sterols in 1 mul of dried serum were derivatized into picolinyl esters (3beta-picolinate) and analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) using the electrospray ionization (ESI) mode. In addition to cholesterol, 19 cholesterol precursors, cholestanol, campesterol, sitosterol, and sitostanol were identified simultaneously. Quantitative analyses for the picolinyl esters of 11 available sterols were performed, and detection limits were found to be less than 1 pg on-column. Reproducibilities and recoveries of 8 noncholesterol sterols were validated according to one-way layout and polynomial equation, respectively. The variances between sample preparations and between measurements by this method were calculated to be 1.6% to 8.2% and 2.5% to 16.5%, respectively. The recovery experiments were performed using 1 mul aliquots of normal human serum spiked with 1 ng to 6 ng of sterols, and recoveries of the sterols ranged from 88.1% to 102.5% with a mean recovery of 98.1%. The present method provides reliable and reproducible results for the identification and quantification of neutral sterols, especially in small volumes of blood samples, which is useful for serological diagnosis of inherited disorders in cholesterol metabolism and for noninvasive evaluation of cholesterol biosynthesis and absorption in humans.

Topics: Caco-2 Cells; Chondrodysplasia Punctata; Chromatography, Liquid; Humans; Picolinic Acids; Reproducibility of Results; Sensitivity and Specificity; Sitosterols; Smith-Lemli-Opitz Syndrome; Spectrometry, Mass, Electrospray Ionization; Sterols; Tandem Mass Spectrometry; Xanthomatosis, Cerebrotendinous

Many severe diseases are caused by defects in lipid metabolism. As a result, patients often accumulate unusual lipids in their blood and tissues, and proper identification of these lipids is essential for correct diagnosis. In this study, we investigated the potential use of proton nuclear magnetic resonance (1H-NMR) spectroscopy to simultaneously identify and quantify (un)usual lipids present in the blood of patients with different inborn errors of lipid metabolism.. We extracted blood plasma or serum lipids in chloroform-methanol (2:1 by volume). After addition of the nonvolatile chemical shift and concentration reference compound octamethylcyclotetrasiloxane, we performed 1H-NMR measurements on a 500-MHz spectrometer. Assignments were based on the literature, computer simulations, and reference spectra of relevant authentic standards.. Spectra of normal plasma samples allowed the identification of 9 lipid species. We found good correlation between conventional methods and 1H-NMR for cholesterol and triglyceride concentrations. We also investigated 4 inborn errors of lipid metabolism (3 in sterol metabolism and 1 in fatty acid metabolism). NMR analysis led to a correct diagnosis for all 4 diseases, whereas the concentration of the diagnostic metabolite could be determined for 3.. 1H-NMR spectroscopy of blood plasma or serum lipid extracts can be used to accurately identify and quantify lipids. The method can also identify unusual lipids in the blood of patients with inborn errors of lipid metabolism. This technique may therefore be applicable in clinical diagnosis and follow-up.

Topics: Adolescent; Adult; Child; Female; Humans; Infant; Lipid Metabolism, Inborn Errors; Lipids; Magnetic Resonance Spectroscopy; Male; Middle Aged; Protons; Reference Values; Refsum Disease; Sitosterols; Smith-Lemli-Opitz Syndrome; Xanthomatosis, Cerebrotendinous