Chondroitin sulfate in normal human plasma is modified depending on the age. Its evaluation in patients with pseudoxanthoma elasticum

Chondroitin Sulfate Disaccharides, a Serum Marker for Primary Serous Epithelial Ovarian Cancer

Glycosaminoglycans are long polysaccharidic chains, which are mostly present in connective tissues. Modified GAG expression in tissues surrounding malignant cells has been shown to contribute to tumor progression, aggressive status and metastasis in many types of cancer. Ovarian cancer is one of the most lethal gynecological malignancies due to its late diagnosis because of the absence of clear symptoms and unavailability of early disease markers. We investigated for the first time GAG changes at the molecular level as a novel biomarker for primary epithelial ovarian cancer. To this end, serum of a cohort of 68 samples was digested with chondroitinase ABC, which releases chondroitin sulfate into disaccharides. After labeling and purification, they were measured by HPLC, yielding a profile of eight disaccharides. We proposed a novel GAG-based score named "CS- bio" from the measured abundance of disaccharides present that were of statistical relevance. CS-bio's performance was compared with CA125, the clinically used serum tumor marker in routine diagnostics. CS-bio had a better sensitivity and specificity than CA125. It was more apt in differentiating early-stage patients from healthy controls, which is of high interest for oncologists.

Online preconcentration and determination of chondroitin sulfate, dermatan sulfate and hyaluronic acid in biological and cosmetic samples using capillary electrophoresis

Capillary electrophoresis with large-volume sample stacking using an electroosmotic flow pump was developed for the determination of chondroitin sulfate, dermatan sulfate, and hyaluronic acid. Central composite design was used to simultaneously optimize the parameters for capillary electrophoresis separation. The optimized capillary electrophoresis conditions were 200 mM sodium dihydrogen phosphate, 200 mM butylamine, and 0.5% w/v polyethylene glycol as a background electrolyte, pH 4 and -16 kV. Exploiting large-volume sample stacking using an electroosmotic flow pump, the sensitivity of the proposed capillary electrophoresis system coupled with UV detection was significantly improved with limits of detection of 3, 5, 1 mg/L for chondroitin sulfate, dermatan sulfate, and hyaluronic acid, respectively. The developed method was applied to the determination of chondroitin sulfate and hyaluronic acid in cell culture media, cerebrospinal fluid, cosmetic products, and supplementary samples with highly acceptable accuracy and precision. Therefore, the proposed capillary electrophoresis approach was found to be simple, rapid, and reliable for the determination of chondroitin sulfate, dermatan sulfate, and hyaluronic acid in cell culture media, cerebrospinal fluid, cosmetic, and supplementary samples without sample pretreatment.

Fibroblast involvement in soft connective tissue calcification

Soft connective tissue calcification is not a passive process, but the consequence of metabolic changes of local mesenchymal cells that, depending on both genetic and environmental factors, alter the balance between pro- and anti-calcifying pathways. While the role of smooth muscle cells and pericytes in ectopic calcifications has been widely investigated, the involvement of fibroblasts is still elusive. Fibroblasts isolated from the dermis of pseudoxanthoma elasticum (PXE) patients and of patients exhibiting PXE-like clinical and histopathological findings offer an attractive model to investigate the mechanisms leading to the precipitation of mineral deposits within elastic fibers and to explore the influence of the genetic background and of the extracellular environment on fibroblast-associated calcifications, thus improving the knowledge on the role of mesenchymal cells on pathologic mineralization.

Age- and gender-related alteration in plasma advanced oxidation protein products (AOPP) and glycosaminoglycan (GAG) concentrations in physiological ageing

BACKGROUND

The authors studied the role of increased oxidative stress in the development of oxidative protein damage and extracellular matrix (ECM) components in ageing. The age- and gender-associated disturbances in connective tissue metabolism were evaluated by the plasma chondroitin sulphated glycosaminoglycans (CS-GAG) and non-sulphated GAG-hyaluronan (HA) measurements. Plasma concentration of advanced oxidation protein products (AOPP) was analysed in order to assess oxidative protein damage and evaluate the possible deleterious role of oxidative phenomenon on tissue proteoglycans' metabolism during the physiological ageing process.

METHODS

Sulphated and non-sulphated GAGs as well as AOPP were quantified in plasma samples from 177 healthy volunteers.

RESULTS

A linear age-related decline of plasma CS-GAG level was found in this study (r=-0.46; p<0.05). In contrast, HA concentrations rise gradually with age (r=0.44; p<0.05) in plasma samples. For both ECM components, the observed differences were not gender-specific. A strong age-dependent relationship has been shown in regard to AOPP. AOPP levels significantly increased with age (r=0.63; p<0.05), equally strongly in both men (r=0.69; p<0.05) and women (r=0.57; p<0.05) during physiological ageing. A significant correlation was found between the concentrations of AOPP and both CS-GAG (r=-0.31; p<0.05) and HA (r=0.33; p<0.05).

CONCLUSIONS

Proceeding with age changes in the ECM are reflected by CS-GAG and HA plasma levels. Strong correlations between AOPP and ECM components indicate that oxidative stress targets protein and non-protein components of the connective tissue matrix during human ageing.

Association between Human Plasma Chondroitin Sulfate Isomers and Carotid Atherosclerotic Plaques

Several studies have evidenced variations in plasma glycosaminoglycans content in physiological and pathological conditions. In normal human plasma GAGs are present mainly as undersulfated chondroitin sulfate (CS). The aim of the present study was to evaluate possible correlations between plasma CS level/structure and the presence/typology of carotid atherosclerotic lesion. Plasma CS was purified from 46 control subjects and 47 patients undergoing carotid endarterectomy showing either a soft or a hard plaque. The concentration and structural characteristics of plasma CS were assessed by capillary electrophoresis of constituent unsaturated fluorophore-labeled disaccharides. Results showed that the concentration of total CS isomers was increased by 21.4% (P < 0.01) in plasma of patients, due to a significant increase of undersulfated CS. Consequently, in patients the plasma CS charge density was significantly reduced with respect to that of controls. After sorting for plaque typology, we found that patients with soft plaques and those with hard ones differently contribute to the observed changes. In plasma from patients with soft plaques, the increase in CS content was not associated with modifications of its sulfation pattern. On the contrary, the presence of hard plaques was associated with CS sulfation pattern modifications in presence of quite normal total CS isomers levels. These results suggest that the plasma CS content and structure could be related to the presence and the typology of atherosclerotic plaque and could provide a useful diagnostic tool, as well as information on the molecular mechanisms responsible for plaque instability.

Structural characterization of the skin glycosaminoglycans in patients with pseudoxanthoma elasticum

BACKGROUND

Complex polysaccharides, glycosaminoglycans (GAGs), their amount, and fine structure were determined in the skin (epidermis + dermis) of pseudoxanthoma elasticum (PXE)-affected patients in comparison with healthy subjects.

METHODS

Nonlesional skin GAGs were extracted and specifically determined by enzymatic treatment and high-performance liquid chromatography separation.

RESULTS

Dermatan sulfate (DS) and hyaluronic acid (HA) were found to be the major GAG species in normal subjects, with contents of approximately 20% for DS and 58% for HA. The chondroitin sulfate (CS) content (unsaturated six-sulfated disaccharide) was approximately 21%. Skin from patients with PXE showed similar HA (61%), DS (22%), and CS (16.7%) contents. No change in the total charge density or nonsulfated/sulfated GAG ratio was noted in PXE-affected subjects, and no modification of the position of the sulfate groups (4s/6s) on the CS/DS backbone. A significant increase (approximately 88%; P < 0.01) in the total amount of GAGs (HA + DS + CS) was found in the PXE group vs. normal subjects, however.

CONCLUSIONS

In the skin of PXE-affected patients, the altered metabolic processes produce an increase in the total amount of GAGs able to accumulate salts, in particular calcium ions, within the elastic fibers, producing ion precipitates that affect the organization of the matrix fiber.