Determination of urinary hexosamines for diagnosis of bladder pain syndrome.

INTRODUCTION AND HYPOTHESIS: Bladder pain syndrome (BPS) is a chronic disease characterized by urgency, bladder pain, and frequency, and urinary glycosaminoglycans are thought to reflect bladder epithelial deficiency in BPS. Sensitive and specific evaluation of total urinary glycosaminoglycans may be useful for the clinical diagnosis of BPS and its treatment. METHODS: A procedure for the simultaneous determination of glucosamine and galactosamine produced from urinary glycosaminoglycans has been performed in BPS patients and healthy subjects. RESULTS: The total content of urinary hexosamines in BPS patients significantly increased by ~130% with the increase in glucosamine greater than galactosamine. CONCLUSIONS: A significant increase in total hexosamines content and in particular in glucosamine belonging to urinary heparan sulfate was determined in BPS patients compared with controls. We propose HS and in particular its low-molecular mass fragments and glucosamine assay as useful markers for a biochemical diagnosis of BPS and for monitoring this syndrome.

Agarose-gel electrophoresis for the quality assurance and purity of heparin formulations.

The adulteration of raw heparin (Hep) with a synthetic oversulfated chondroitin sulfate (OSCS) not found in nature produced in 2007-2008 a global crisis giving rise to the development of additional, new and specific methods for its quality assurance and purity. In this study, a simple and sensitive agarose-gel electrophoresis method has been developed for the visualization of OSCS in Hep samples along with other natural glycosaminoglycans possibly present as "process-related impurities", in particular dermatan sulfate (DS) and chondroitin sulfate (CS). Agarose-gel electrophoresis under non-conventional conditions is able to separate OSCS from Hep with its two components, the slow-moving and fast-moving species, DS and CS by performing separation for 15 h (overnight) and under high voltage (100 mA, ∼200 V). Densitometric scanning enabled us to calculate a limit of detection of ∼0.5 µg OSCS with a linear behaviour from 0.1 to 5 µg, comparable to CS/DS. Contaminated samples from Hep manufacturers were analyzed and quantitative data were found comparable to previous studies. Due to its capacity to process many samples in a single run and to the equipment commonly available in laboratories, this analytical method would be suitable for the identification and quantification of contamination by other polysaccharides, in particular OSCS and DS, within Hep preparations and formulations.

Glycosaminoglycan content in term and preterm milk during the first month of lactation.

BACKGROUND: In a recent study, we performed a complete structural characterization of glycosaminoglycans (GAGs) in human mature milk. However, no data are available on the total content of GAGs in human milk from healthy mothers having delivered term or preterm newborns. OBJECTIVES: In this study, we evaluated the total content of GAGs in pooled milk from healthy mothers having delivered term or preterm newborns during the first month of lactation. METHODS: Highly specific and sensitive analytical approaches were used to quantify human milk total GAGs. RESULTS: Highest GAG values are present at day 4 (9.3 and 3.8 g/l in preterm and term milk, respectively), followed by a progressive decrease up to day 30 (4.3 and 0.4 g/l). The more remarkable differences are related to the first phases of lactation in which a strong decrease in GAGs was observed between days 4 and 10 (about -73% in term and -50% in preterm newborns). CONCLUSIONS: During the first month of lactation, the absolute amount of polysaccharides was constantly and significantly higher in preterm than in term milk, with a similar behavior in the decrease. These data further indicate that human milk GAGs may have an active role in protecting newborns during the first phases of lactation.

Plasmatic and Urinary Glycosaminoglycans Characterization in Mucopolysaccharidosis II Patient Treated with Enzyme-Replacement Therapy with Idursulfase.

We report the structural characterization of plasmatic and urinary GAGs in a patient affected by MPS II (Hunter syndrome) before and during the first 10 months of enzyme-replacement therapy (ERT). Plasmatic GAGs before ERT were rich in pathological DS consisting of iduronic acid (IdoA) and composed of ~90% ΔDi4s and trace amounts of disulfated disaccharides. DS was also characterized as the main (~90%) urinary GAG mainly composed of ~90% ΔDi4s with minor percentages of monosulfated and disulfated disaccharides, in particular ΔDi2,4dis. After 300 days of ERT, plasmatic DS strongly decreased but ~14% of IdoA-rich ΔDi4s was still detected. Similarly, urinary galactosaminoglycans were mainly composed of 78% ΔDi4s, ~11% ΔDi6s and ~4% ΔDi0s with the persistence of ΔDi2,4dis (~4%). About 40% of IdoA-formed ΔDi4s were also calculated, thus confirming that pathological DS is still present in excreted urinary GAGs during ERT. By considering the % of IdoA, we observed rather similar kinetics of excretion in fluids from the beginning of the treatment. Immediately after the first enzyme infusion, a large amount of abnormal DS is removed from tissues reaching the blood compartment and eliminated via the urine, and this process lasts for about 2 weeks. After this, the percentage of IdoA-rich material present in biological fluids remains fairly constant over the following 9 months of treatment. To date, these are the first data regarding plasmatic and urinary kinetics directly measured on products released by the activity of the recombinant enzyme Idursulfase, iduronate-2-sulfatase, evaluated using specific and sensitive analytical procedures.

Fine structural characterization of chondroitin sulfate in urine of bladder pain syndrome subjects.

INTRODUCTION AND HYPOTHESIS: Urothelial glycosaminoglycans (GAGs) are decreased in bladder pain syndrome (BPS), and urinary GAGs are thought to reflect this deficiency. In previous researches, urine GAG levels were found increased, decreased, or similar between BPS and controls. Additionally, no study is available on the structure characterization of urinary chondroitin sulfate (CS) in BPS patients. METHODS: CS in the urine of BPS-affected patients and controls has been determined by specific electrophoresis, along with total GAGs and heparan sulfate (HS) percentage, and CS disaccharides have been quantified by high-performance liquid chromatography. RESULTS: No significant differences were obtained for total amount of GAGs, absolute content of CS and HS, and their relative percentages. Moreover, no differences were observed for CS structure confirming similar urine CS composition in BPS subjects and controls. CONCLUSIONS: This study found no significant differences of BPS and control urine GAG levels and CS structure to allow use of these parameters as diagnostic markers for BPS diagnosis.

Composition and structure elucidation of human milk glycosaminoglycans.

To date, there is no complete structural characterization of human milk glycosaminoglycans (GAGs) available nor do any data exist on their composition in bovine milk. Total GAGs were determined on extracts from human and bovine milk. Samples were subjected to digestion with specific enzymes, treated with nitrous acid, and analyzed by agarose-gel electrophoresis and high-performance liquid chromatography for their structural characterization. Quantitative analyses yielded ∼7 times more GAGs in human milk than in bovine milk. In particular, galactosaminoglycans, chondroitin sulfate (CS) and dermatan sulfate (DS), were found to differ considerably from one type of milk to the other. In fact, hardly any DS was observed in human milk, but a low-sulfated CS having a very low charge density of 0.36 was found. On the contrary, bovine milk galactosaminoglycans were demonstrated to be composed of ∼66% DS and 34% CS for a total charge density of 0.94. Structural analysis performed by heparinases showed a prevalence of fast-moving heparin over heparan sulfate, accounting for ∼30-40% of total GAGs in both milk samples and showing lower sulfation in human (2.03) compared with bovine (2.28). Hyaluronic acid was found in minor amounts. This study offers the first full characterization of the GAGs in human milk, providing useful data to gain a better understanding of their physiological role, as well as of their fundamental contribution to the health of the newborn.

Effect of 6 years of enzyme replacement therapy on plasma and urine glycosaminoglycans in attenuated MPS I patients.

Enzyme-replacement therapy (ERT) is a new option for the clinical management of MPS I. However, no detailed data are available on the structural characterization of glycosaminoglycans (GAGs) in the urine and plasma of patients before ERT and during treatment regimens. Before ERT and over a two-week period of enzyme infusion, GAGs in urine and plasma were analyzed in two patients with the Hurler-Scheie form of MPS I subjected to ERT for 6 years. In both patients before ERT, high amounts of a GAG were found in the urine, composed in particular of a high molecular mass polymer (approximately 13,000-13,500) consisting of approximately 75-78% iduronic acid and rich in 4-sulfated disaccharides (DeltaDi4s) and attributable to DS. Furthermore, a high amount of this GAG was directly detected in the blood. Plasma GAGs in MPS I patients subjected to ERT were found to be comparable to those of normal subjects with the absence of heparan sulfate and of DS. On the contrary, a polysaccharide possessing a high molecular mass, approximately 11,500-12,000, lower than the polymer extracted before ERT but slightly higher than the controls (approximately 11,000), was found in the urine of both patients. This macromolecule was characterized as a mixture of DS/chondroitin sulfate based on the high percentage of 4-sulfated disaccharide (4s/6s ratio of approximately 3.1) and iduronic acid ( approximately 60%). These results are indicative of the incapacity of ERT at the standard dose to definitively eliminate DS from the urine. Finally, a variable effect of ERT depending on each administration was also observed.

Comparison of cetylpyridinium chloride and cetyltrimethylammonium bromide extractive procedures for quantification and characterization of human urinary glycosaminoglycans.

BACKGROUND: Glycosaminoglycans (GAGs) are natural complex polysaccharides that are important in several pathological processes. Urinary GAGs have long been investigated for their possible modifications in many pathological conditions. In some cases, they have been found to have diagnostic utility. As a result, the measurement of GAGs in urine is gradually gaining importance. Cetylpyridinium chloride (CPC) and cetyltrimethylammonium bromide (CETAB) are generally used to extract urinary GAGs prior to analysis. In this study, we evaluated the extraction of human urinary GAGs using CPC in comparison with CETAB. METHODS: Extracted urinary GAGs were qualitatively and quantitatively analyzed by agarose-gel electrophoresis in the presence of sequential staining and densitometric scanning. This procedure was able to give more reproducible and reliable results for urinary GAGs, and high performance liquid chromatography (HPLC) was used for the evaluation of chondroitin sulfate (CS) disaccharides. RESULTS: Differences were observed between CPC and CETAB extract protocols. The absolute amount of CS evaluated by electrophoresis was found to be similar for the two protocols. However, the heparan sulfate (HS) concentration was calculated to be approximately 3.3 times greater for CPC than CETAB. When calculated in relative percentage, 33.6% HS was determined for CPC and 10.0% for CETAB. These results show a quantitative expression for greater recovery of HS by using CPC protocol than CETAB. No significant differences were found between CS quantified by agarose-gel and HPLC. In addition, no differences were observed for the CS disaccharide composition purified by using CPC or CETAB, and quite similar results were observed for 4s/6s disaccharide ratios and charge density values. CONCLUSIONS: Extract procedures for urinary GAGs using CPC or CETAB are able to recover similar amounts of CS quantified by agarose-gel electrophoresis and HPLC. However, CPC yields greater recovery of HS than the CETAB protocol; an increase of approximately 3.3 times as evaluated by electrophoresis. This different capacity of HS extraction between CPC and CETAB should be considered when urinary GAGs of subjects affected by various diseases and related pharmacological treatments are considered, or meta-analysis is performed comparing various studies and trials performed under different experimental conditions.

Determination of molecular mass values of chondroitin sulfates by fluorophore-assisted carbohydrate electrophoresis (FACE).

Fluorophore-assisted carbohydrate electrophoresis (FACE) was applied to determine the molecular mass (M) values of various chondroitin sulfate (CS) samples. After labeling with 8-aminonaphthalene-1,3,6-trisulfonic acid (ANTS), FACE was able to resolve each CS sample as a discrete band depending on the M value. After densitometric acquisition, the migration distance of each CS standard was acquired and the third grade polynomial calibration standard curve was determined by plotting the logarithms of the M values as a function of migration ratio. Purified CS samples of different origin and the European Pharmacopeia CS standard were analyzed by both FACE and conventional high-performance size-exclusion liquid chromatography (HPSEC) methods. The molecular weight value on the top of the chromatographic peak (M(p)), the number-average M(n), weight-average M(w), and polydispersity (M(w)/M(n)) were examined by both techniques and found to be quite similar. This study demonstrates that FACE analysis is a suitable, sensitive and simple method for the determination of the M values of CS macromolecules with possible utilization in virtually any kind of research and development such as quality control laboratories.

Fluorophore-assisted carbohydrate electrophoresis for the determination of molecular mass of heparins and low-molecular-weight (LMW) heparins.

We report the use of fluorophore-assisted carbohydrate electrophoresis (FACE) to determine the molecular mass (M) values of heparins (Heps) and low-molecular-weight (LMW)-Hep derivatives. Hep are labeled with 8-aminonaphthalene-1,3,6-trisulfonic acid and FACE is able to resolve each fraction as a discrete band depending on their M. After densitometric acquisition, the migration distance of each Hep standard is acquired and the third-grade polynomial calibration standard curve is determined by plotting the logarithms of the M values as a function of migration ratio. Purified Hep samples having different properties, pharmaceutical Heps and various LMW-Heps were analyzed by both FACE and conventional high-performance size-exclusion liquid chromatography (HPSEC) methods. The molecular weight value on the top of the chromatographic peak (Mp), the number-average Mn, weight-average Mw and polydispersity (Mw/Mn) were examined by both techniques and found to be similar. This approach offers certain advantages over the HPSEC method. The derivatization process with 8-aminonaphthalene-1,3,6-trisulfonic acid is complete after 4 h so that many samples may be analyzed in a day also considering that multiple samples can be run simultaneously and in parallel and that a single FACE analysis requires approx. 15 min. Furthermore, FACE is a very sensitive method as it requires approx. 5-10 microg of Heps, about 10-100-fold lower than samples and standards used in HPSEC evaluation. Finally, the utilization of mini-gels allows the use of very low amounts of reagents with neither expensive equipment nor any complicated procedures having to be applied. This study demonstrates that FACE analysis is a sensitive method for the determination of the M values of Heps and LMW-Heps with possible utilization in virtually any kind of research and development such as quality control laboratories due to its rapid, parallel analysis of multiple samples by means of common and simple largely used analytical laboratory equipment.