Oxidative modification of apolipoprotein E in human very-low-density lipoprotein and its inhibition by glycosaminoglycans

The mechanism of metal ion-catalyzed oxidative modification of apolipoprotein E (apoE) in human very-low-density lipoprotein (VLDL) and its inhibition by glycosaminoglycan (GAG) was investigated in vitro. The VLDL oxidation catalyzed by Cu2+ led to the lipid peroxidation, the formation of aggregates, and covalent modification of apoE. The modified apoE lost heparin-binding activity. These results suggest that the lipid peroxidation of VLDL and modification of apoE cause impairment of lipid uptake by cells and deposit the oxidized lipids in the tissues. The lipid peroxidation and oxidative modification of apoE in VLDL mediated by Cu2+ and an aqueous radical generator were suppressed by GAG, heparan sulfate, heparin, and chondroitin sulfate A, even though GAGs demonstrated no ability to scavenge alpha,alpha-diphenyl-beta-picrylhydrazyl radical. There were no relationships between inhibitory activity of GAGs in the VLDL oxidation and their number of sulfate groups which possess chelating activity of metal ion. Therefore, it can be considered that the inhibition of VLDL oxidation by GAGs is possibly due to the interaction between GAG and VLDL which bring about the steric hindrance, interference with the reaction between VLDL particle and the reactive oxygen species. These studies suggest that GAGs preserve the biological functions of apoE from oxidative stress.

Effects of chondroitin sulfate-C on bradykinin-induced proteoglycan depletion in rats

Depletion of the proteoglycan content of articular cartilage was induced by injecting bradykinin (30-300 mumol/l, 50 microliters/knee) into the left knee articular cavities of rats 3 times a day for 2 days. The degree of the reduction in the intensity of histopathological safranin O staining was used as an index of proteoglycan depletion. Bradykinin reduced the cartilage proteoglycan contents of the knee joints of non-injected limbs in a dose-dependent manner and at 300 mumol/l markedly reduced these contents, but evoked no inflammatory changes. The extent of the reduction of the cartilage proteoglycan contents induced by bradykinin injection depended on the dose and injection frequency. Chondroitin sulfate-C (CAS 25322-46-7, Chondroitin ZS Tab) (30-1,000 mg/kg/day) administered orally to rats for 14 days inhibited the bradykinin-induced proteoglycan depletion of the articular cartilage in a dose-dependent manner. These results suggest that a reduction of the proteoglycan content of cartilage, like that associated with osteoarthritis, was induced by injecting bradykinin into the knee articular cavities of rats and chondroitin sulfate-C protected against this effect.

Growth factor and matrix molecules preserve cell function on thermally responsive culture surfaces

Thermally-responsive culture surfaces were designed using copolymers of N-isopropylacrylamide, 4-(aminomethyl)styrene, and acrylic acid. These surfaces contained functional amine and carboxyl groups, which allowed biomolecules to be grafted by amide formation. Epidermal growth factor (EGF), and extracellular matrix (ECM) molecules (collagen type IV, and chondroitin sulfate) were investigated, as surface-grafted biomolecules, for their ability to stimulate cell attachment, proliferation, and function by signaling only from the basal side of cultured cells. Surface analysis of biomolecule-grafted porous inserts showed covalent binding of biomolecules to either amine or carboxyl groups. Multiple attachment to amine and/or carboxyl groups served as cross-linking points that made the polymer hydrogel permanently adherent to the culture surface. Immunofluorescence microscopy techniques gave positive identification of grafted biomolecules. Grafting of EGF improved cell proliferation versus that on nongrafted controls, or controls grafted only with ECM molecules. ECM grafting induced cell attachment on attachment-resistant surfaces. Analysis of trans-epithelial resistance, fluid transport, and polarized g-glutamyl transpeptidase activity indicated that simultaneous grafting of both EGF and ECM produced better polarized cell function than nongrafted controls, or controls grafted with only one type of biomolecule. Covalent grafting of biomolecules did not interfere with cells ability to detach from thermally responsive surfaces upon temperature decrease.

Heparan sulphates upregulate regeneration of transected sciatic nerves of adult guinea-pigs

The increased content of soluble glycosaminoglycan-containing forms in sciatic nerves during recovery from crush injury [Shum & Chau (1996) J. Neurosci. Res., 46, 465] suggests that the glycosaminoglycans modulate the environment for post-traumatic tissue remodelling and axonal regrowth. To test this, defined amounts of soluble heparan sulphates from bovine kidney or guinea-pig nerve were introduced into the regenerating environment via silicone conduits that bridged 8-mm gaps of transected sciatic nerves of adult guinea-pigs. Controls were bridged using the phosphate-buffered saline (PBS) vehicle or a chondroition sulphate preparation from whale cartilage. After timed periods of recovery, the animals were assessed for electromyographic signals at the target gastrocnemius muscle to determine the conduction velocity across the bridged nerve. Sections of the bridge were also histologically examined for nerve fibres. Transected sciatic nerves bridged with heparan sulphates or chondroitin sulphate showed earlier stimulated myelination of axons (week 5-6) than PBS-bridged nerves (week 9). Initial electromyographic indication of reconnection with the target was at week 9 post-transection. In the course of 20 weeks, transected sections of the bridge indicated similar numbers of unmyelinated axons irrespective of bridge material, but distinctly higher numbers of myelinated axons in heparan sulphate-bridged nerves than either PBS- or chondroitin sulphate-bridged nerves. At the end of the same period, heparan sulphate-bridged nerves resumed normal conduction velocities, but both PBS- and chondroitin sulphate-bridged nerves remained at 50% of that of the intact contralateral nerves. These results are the first to demonstrate that supplementation of soluble heparan sulphate to the fluid regenerative neural environment can restore functional, axonal reconnection of the severed nerve with the target muscle.

Retinoic acid alters the mechanism of attachment of malignant astrocytoma and neuroblastoma cells to thrombospondin-1

Based on the hypothesis that the attachment of neuroectodermal cells to thrombospondin-1 (TSP-1) may affect tumor spread and play a role in the anti-tumor effects of retinoic acid, we investigated the expression of TSP-1 in these cells in situ and the effect of retinoic acid on the morphology of TSP-1-adherent neuroblastoma (SK-N-SH) and malignant astrocytoma (U-251MG) cells in vitro. TSP-1-adherent SK-N-SH cells demonstrated process outgrowth, with further neuronal differentiation after retinoic acid treatment, consistent with the in situ studies showing that TSP-1 expression occurs in a differentiation-specific manner in neuroblastic tumors. TSP-1-adherent U-251MG cells failed to spread; however, after retinoic acid treatment the cells demonstrated broad lamellipodia containing radial actin fibers and organization of integrins alpha3beta1 and alpha5beta1 in clusters in lamellipodia and filopodia. The attachment of both SK-N-SH and U-251MG cells to TSP-1 was found to be mediated by heparan sulfate proteoglycans, integrins, and the CLESH-1 adhesion domain first identified in CD36. Heparin and heparitinase treatment inhibited TSP-1 attachment. Integrins alpha3beta1 and alpha5beta1 mediated TSP-1 attachment of SK-N-SH cells, and integrins alpha3beta1, alpha5beta1, and alphavbeta3 mediated TSP-1 attachment of U-251MG cells. Attachment was dependent on the RGD sequence which is located in the carboxy-terminus of TSP-1. Treatment with a pharmacologic dosage of retinoic acid altered the TSP-1 cell adhesion mechanism in both cell lines in that neither heparin nor micromolar concentrations of the RGD peptide inhibited attachment; after treatment, attachment was inhibited by the CSVTCG peptide located in the type I repeat domain of TSP-1 and a recombinant adhesion domain (CLESH-1) from CD36. Expression of CD36 was found in the retinoic acid-treated U-251MG cells. These data indicate that neuroectodermally derived cells utilize several mechanisms to attach to TSP-1, and these are differentially modulated by treatment with retinoic acid. These data also suggest that the CSVTCG sequence of TSP-1 modulates or directs cytoskeletal organization in neuroblastoma and astrocytoma cells.

DSD-1-proteoglycan is the mouse homolog of phosphacan and displays opposing effects on neurite outgrowth dependent on neuronal lineage

DSD-1-PG is a chondroitin sulfate proteoglycan (CSPG) expressed by glial cells that can promote neurite outgrowth from rat embryonic mesencephalic (E14) and hippocampal (E18) neurons, an activity that is associated with the CS glycosaminoglycans (GAGs). Further characterization of DSD-1-PG has included sequencing of peptides from the core protein and the cloning of the corresponding cDNA using polyclonal antisera against DSD-1-PG to screen phage expression libraries. On the basis of these studies we have identified DSD-1-PG as the mouse homolog of phosphacan, a neural rat CSPG. Monoclonal antibodies 3H1 and 3F8 against carbohydrate residues on rat phosphacan recognize these epitopes on DSD-1-PG. The epitopes of the antibodies, L2/HNK-1 and L5/Lewis-X, which have been implicated in functional interactions, are also found on DSD-1-PG. Although DSD-1-PG has previously been shown to promote neurite outgrowth, its upregulation after stab wounding of the CNS and its localization in regions that are considered boundaries to axonal extension suggested that it may also have inhibitory functions. Neonatal dorsal root ganglion (DRG) explants grown on a rich supportive substrate (laminin) with and without DSD-1-PG were strikingly inhibited by the proteoglycan. The inhibitory effects of DSD-1-PG on the DRG explants were not relieved by removal of the CS GAGs, indicating that this activity is associated with the core glycoprotein. The neurite outgrowth from embryonic hippocampal neurons on laminin was not affected by the addition of DSD-1-PG. This indicates that DSD-1-PG/mouse phosphacan can have opposing effects on the process of neurite outgrowth dependent on neuronal lineage.

Chondroitin-4-sulfate protects high-density lipoprotein against copper-dependent oxidation

We investigated the effect of chondroitinsulphate (CS), the major glycosaminoglycan of the arterial wall, on the oxidation of human high-density lipoprotein (HDL) by kinetic analysis. Chondroitin-4-sulfate (C4S) increased the lag time and reduced the maximum rate of HDL oxidation induced by Cu2+, as assessed by monitoring both conjugated diene formation and low-level chemiluminescence. On the contrary, chondroitin-6-sulfate (C6S) was ineffective. Dermatansulfate exhibited an inhibitory effect comparable to that of C4S. C4S protected also the protein moiety of HDL, as it reduced tryptophan destruction by lipid-oxidizing species and delayed the formation of fluorescent adducts between end products of lipid peroxidation and amino acid residues. Again, C6S was ineffective. C4S was able to bind Cu2+; this resulted in less Cu2+ available for HDL oxidation and likely represented the mechanism of the protective effect. Neither C4S nor C6S affected HDL oxidation by peroxyl radicals, indicating that free radical scavenging activity was not involved in the protective effect. These results suggest that C4S might prevent the oxidative modification of HDL in arterial wall, thus preserving its antiatherogenic potential for reverse cholesterol transport and, possibly, for clearance of oxidized lipids.

Dextran sulfate inhibits E-selectin-mediated neutrophil adhesion to endotoxin-activated vascular endothelial cells

Effects of heparin-like glycosaminoglycans (h-GAGs) on neutrophil adhesion to endothelial cells (ECs) were investigated under physiological flow conditions using human umbilical vein ECs. Neutrophil adhesion to lipopolysaccharide-activated ECs was assayed under rotating conditions with addition of h-GAGs or monoclonal antibodies (mAbs) against selectins. Neutrophil adhesion to activated ECs under rotating conditions was suppressed completely by anti-E-selectin mAb and partially by anti-L-selectin mAb. Addition of dextran sulfate or heparin also significantly inhibited neutrophil adhesion to ECs under the same conditions. Moreover, effects of h-GAGs on neutrophil adhesion to recombinant E-selectin-coated plates were analyzed. Anti-E-selectin mAb and dextran sulfate, but not heparin, significantly inhibited neutrophil adhesion to E-selectin-coated plates. Results suggest that dextran sulfate inhibited E-selectin-mediated neutrophil adhesion to endotoxin-activated ECs under physiologic flow conditions.

Impact of various glycosaminoglycans upon cAMP-dependent protein kinase

The physiological effects of the second messenger cAMP are displayed by cAMP-dependent protein kinase-medicated phosphorylation of specific target proteins which in turn control diverse cellular functions. We have determined this enzyme substrate phosphorylation in the presence of various glycosaminoglycans using a cAMP-dependent protein kinase isolated from rat liver. The results indicate that sulfated and unsulfated polysaccharides are able to inhibit phosphorylation of histone type IIa catalysed by cAMP-dependent protein kinase. Based on their impact upon substrate phosphorylation, glycosaminoglycans can be divided into three groups: group I with the highest inhibitory effect: dermatan sulfate and heparan sulfate; group II: chondroitin 4-sulfate and group III with the lowest inhibitory effect: chondroitin 6-sulfate, keratan sulfate and hyaluronic acid.

Cellular adhesion mediated by factor J, a complement inhibitor. Evidence for nucleolin involvement

Factor J (FJ) is a complement inhibitor that acts on the classical and the alternative pathways. We demonstrated FJ-cell interactions in fluid phase by flow cytometry experiments using the cell lines Jurkat, K562, JY, and peripheral blood lymphocytes. FJ bound to plastic plates was able to induce in vitro adhesion of these cells with potency equivalent to fibronectin. As evidence for the specificity of this reaction, the adhesion was blocked by MAJ2, an anti-FJ monoclonal antibody, and by soluble FJ. Attachment of the cells required active metabolism and cytoskeletal integrity. The glycosaminoglycans heparin, heparan sulfate, or chondroitin sulfates A, B, and C inhibited to varying degrees the binding of FJ to cells, as did treatment with chondroitinase ABC. In the search for a putative receptor, a protein of 110 kDa was isolated by affinity chromatography, and microsequence analysis identified this protein as nucleolin. Confocal microscopy evidenced the presence of nucleolin in cell membrane by immunofluorescence with monoclonal (D3) and polyclonal anti-nucleolin antibodies in Jurkat cells. The interaction FJ-nucleolin was evidenced by Western blot and enzyme-linked immunosorbent assay. Furthermore, purified nucleolin and D3 inhibited adhesion of Jurkat cells to immobilized FJ, suggesting that the interaction was specific and that nucleolin mediated the binding.

[Death of articular chondrocytes. Mechanisms and protection]

APOPTOSIS IN JOINT CARTILAGE: Apoptosis is the physiologically programmed death of cells to be distinguished from necrosis which caused non-programmed cell death. In joint cartilage, more than 50% of the chondrocytes show signs of apoptosis compared with 10% in normal cartilage. ROLE OF NITRIC OXIDE: In osteoarthritis the production of nitric oxide (NO) appears to be increased, inducing apoptosis of articular chondrocytes stimulated by interleukin 1. NO inhibitors can limit the progression of experimentally induced joint lesions in animal models. IN VITRO RESULTS: The protective effect of the chondroitin sulfates CS4 and CS6 against death of chondrocytes exposed to NO has been demonstrated in vitro. Chondrocytes for New Zealand white rabbits were cultivated in the presence of an NO donor for exposure durations from 12 to 72 hours, with or without adding CS 4&6 to the culture medium. After 3 days of culture, NO induced a significant rise in the number of apoptotic chondrocytes. In 70% of the cases, preventive treatment with 100 micrograms/ml CS 4&6 lowered the number of dead cells. This cytoprotective effect reached a mean 28% and was inversely dependent on the duration of exposure to the NO donor.

Determinants of weddellite formation: chondroitin sulfates and citrate determine weddellite formation in vitro

In synthetic urine (SU), addition of oxalate tends to form monohydrates of calcium oxalate. However, addition of oxalate to natural urine preferably forms calcium oxalate dihydrate (COD). Urine apparently contains a determinant for COD formation. To identify the determinant, the effects of pH, temperature, oxalate, calcium, urate, citrate, magnesium, sulfate and chondroitin sulfates (CS) on calcium oxalate crystal formation were studied. Lower temperatures, higher oxalate concentrations and higher pH favored COD formation in a SU. Mixed CS in the presence of citrate were the most decisive determinant of COD formation. Substitution of CS for agar and gelatin produced similar results, indicating that the colloidal effect of the macromolecules determines COD formation. Identification of the determinants led to a simple, reproducible method of COD formation in SU without natural urine. Addition of strontium to SU resulted in dodecahedral bipyramids. Interpenetration twinning of bipyramids occur within seconds of the crystal formation.

Effect of compounds with antibacterial activities in human milk on respiratory syncytial virus and cytomegalovirus in vitro

The effect of some antibacterial compounds present in human milk were tested for antiviral activity against respiratory syncytial virus, Semliki Forest virus and cytomegalovirus. These included the gangliosides GM1, GM2 and GM3, sialyl-lactose, lactoferrin and chondroitin sulphate A, B and C, which were all tested for their ability to inhibit the viruses in cell culture. Of the compounds tested, only the ganglioside GM2, chondroitin sulphate B and lactoferrin inhibited the absorption and growth of respiratory syncytial virus in cell culture, and none inhibited the growth of Semliki Forest virus, indicating that lipid antiviral activity was not associated with any of the gangliosides. While the concentrations of these two compounds required to inhibit respiratory syncytial virus were in excess of those present in human milk, sialyl-lactose concentrations similar to those present in human milk increased the growth of cytomegalovirus. Lactoferrin was confirmed as inhibiting both respiratory syncytial virus and cytomegalovirus growth in culture even when used at lower concentrations than those present in human milk. The antiviral activities of GM2, chondroitin sulphate B and lactoferrin were tested when added to an infant formula. Lactoferrin continued to have antiviral activity against cytomegalovirus, but a lower activity against respiratory syncytial virus; ganglioside GM2 and chondroitin sulphate B still maintained antiviral activity against respiratory syncytial virus.

Heparin increases protein S levels in cultured endothelial cells by causing a block in degradation

Heparin is a natural anticoagulant molecule that can alter the activity and/or levels of other molecules involved in blood coagulation. Protein S, an anticoagulant protein, is synthesized and released into the plasma by endothelial cells. Immunological assays revealed a significant increase in protein S found in the media and in the endothelial cells after heparin treatment. Time assays revealed a rapid heparin effect on protein S levels in the media. Upon treatment with chondroitin sulfate, a small increase in the amount of protein S in the conditioned medium was also detected but the change in the cell-associated protein S levels after chondroitin sulfate treatment was a decrease rather than the increase implying that heparin and chondroitin sulfate are operating through different mechanisms. Radioimmunoprecipitations and cycloheximide treatments indicated no significant difference in protein S synthesis in heparin treated cells. In experiments comparing heparin and ammonium chloride effects, heparin seems to mimic the ammonium chloride effect on the levels of protein S in the media. Together, the data indicate that heparin increases the levels of protein S found in the media of cultured endothelial cells by producing a specific block in protein S degradation.

Chondroitin sulfates modulate axon guidance in embryonic Xenopus brain

Chondroitin sulfate proteoglycans display both inhibitory and stimulatory effects on cell adhesion and neurite outgrowth in vitro. The functional activity of these proteoglycans appears to be context specific and dependent on the presence of different chondroitin sulfate-binding molecules. Little is known about the role of chondroitin sulfate proteoglycans in the growth and guidance of axons in vivo. To address this question, we examined the effects of exogenous soluble chondroitin sulfates on the growth and guidance of axons arising from a subpopulation of neurons in the vertebrate brain which express NOC-2, a novel glycoform of the neural cell adhesion molecule N-CAM. Intact brains of stage 28 Xenopus embryos were unilaterally exposed to medium containing soluble exogenous chondroitin sulfates. When exposed to chondroitin sulfate, NOC-2(+) axons within the tract of the postoptic commissure failed to follow their normal trajectory across the ventral midline via the ventral commissure in the midbrain. Instead, these axons either stalled or grew into the dorsal midbrain or continued growing longitudinally within the ventral longitudinal tract. These findings suggest that chondroitin sulfate proteoglycans indirectly modulate the growth and guidance of a subpopulation of forebrain axons by regulating either matrix-bound or cell surface cues at specific choice points within the developing vertebrate brain.

Isolation and identification of chondroitin sulfates from the mud snail

Chondroitin sulfates were isolated from the mud snail. For the quantitative analysis of enzymatic digestion products of isolated chondroitin sulfates, strong anion exchange-high performance liquid chromatography (SAX-HPLC) was performed. By the action of chondroitinase ABC, three unsaturated disaccharides 2-acetamide-2-deoxy-3-O-(beta-D-gluco-4-enepyranosyluronic acid)-D-galactose (delta Di-OS), 2-acetamide-2-deoxy-3-O-(beta-D-gluco-4-enepyranosyluronic acid)-6-O-sulfo-D-galactose (delta Di-6S) and 2-acetamide-2-deoxy-3-O-(beta-D-gluco-4-enepyranosyluronic acid)-4-O-sulfo-D-galactose (delta Di-4S) were produced from the mud snail chondroitin sulfates. The analysis showed that relative proportion of delta Di-OS/delta Di-6S/delta Di-4S was 58.7/3.1/38.2. The immunomodulating activity of chondroitin sulfate was examined by cell proliferation assay and these results suggest that it might be a immunosuppressant.

Management of heparin-induced thrombocytopenia during continuous renal replacement therapy

Heparin-associated thrombocytopenia occurred in a patient during continuous renal replacement therapy (CRRT), resulting in repeated clotting of the extracorporeal circuit and spontaneous hemorrhage. The peripheral platelet count initially appeared to improve by changing to prostacyclin and dalteparin. However, repeated CRRT circuit clotting recurred, and the platelet count decreased once again. This time the synthetic heparinoid, Orgaran (danaparoid), was used and was associated with successful CRRT and return of the platelet count.

Sulfation of extracellular matrices modifies growth factor effects on type II cells on laminin substrata

The alveolar basement membrane contains a variety of extracellular matrix (ECM) molecules, including laminin and sulfated glycosaminoglycans of proteoglycans. These mixtures exist within microdomains of differing levels of sulfate, which may specifically interact to be key determinants of the known capacity of the type II cell to respond to certain growth factors. Isolated type II cells were exposed to either acidic fibroblast growth factor (FGF-1), basic fibroblast growth factor (FGF-2), or keratinocyte growth factor (KGF; FGF-7) on culture wells precoated with laminin alone or in combination with chondroitin sulfate (CS), high-molecular-weight heparin, or their desulfated forms. Desulfated heparin significantly elevated FGF-1- and FGF-2-stimulated DNA synthesis, whereas desulfated CS and N-desulfated heparin elevated FGF-7-stimulated DNA synthesis by type II cells on laminin substrata. When FGF-1 was mixed into the various test matrix substrata, DNA synthesis was significantly increased in all cases. These results demonstrated that decreased levels of sulfate in ECM substrata act to upregulate responses to heparin-binding growth factors by alveolar epithelial cells on laminin substrata.

Influence of mechanical stretch on thrombin regulation by fetal mixed lung cells

Respiratory distress syndrome (RDS) is characterized by intrapulmonary fibrin deposition, which can adversely affect surfactant function, and stimulate fibroblast proliferation, which may contribute to the development of bronchopulmonary dysplasia (BPD). We speculated that the premature lung may have impaired regulation of thrombin, thus making preterm infants susceptible to fibrin formation within the lung. Therefore, we studied the effect of stretch, which simulates fetal breathing movements (FBMs), on the generation and inhibition of a key hemostatic enzyme-thrombin-by rat fetal mixed lung cells (FMLCs). Our results showed that stretch induced glycosaminoglycan production with increased antithrombin activity due to an increase in the concentration of active chondroitin sulfate. Stretch downregulated secretion of tissue factor procoagulant activity, which may lead to decreased thrombin generation on the surface of FMLCs. Overall, stretch enhanced the local control of thrombin by FMLCs. These results suggest that premature infants, who will have experienced less FBM, may have impaired thrombin regulation. Impaired thrombin regulation likely contributes to increased fibrin deposition and, potentially, the development of BPD.

Pharmacokinetics of danaparoid sodium, dalteparin sodium and heparin determined by inhibitory effect on the activated coagulation factor X activity after single intravenous administration in rabbits

The inhibitory effect on the activated coagulation factor X activity (anti-Xa activity) in plasma and urine of danaparoid sodium (DAS, CAS 9005-49-6) was compared with that of dalteparin sodium (DLS, CAS 9041-08-1) and heparin (CAS 9005-49-6) after single intravenous administration at a dose of 640 anti-Xa U/kg to male rabbits. The elimination of half-life of DAS was 9.90 h and was 6.0 times longer than that of DLS and 16.5 times longer than that of heparin. The area under the plasma concentration-time curve (AUC) of DAS was 47.13 +/- 14.55 anti-Xa U.h/ml and was 2.4 times larger than that of DLS and 2.9 times larger than that of heparin. The urinary cumulative excretion of anti-Xa activity of DAS and DLS was 42.6 +/- 6.4% and 16.4 +/- 0.8% of dose, respectively, in 24 h after dosing, respectively. But the anti-Xa activity in urine was not detected at any sampling points after administration of heparin. DAS has a longer elimination half-life and a higher renal excretion of anti-Xa activity than that of DLS and heparin. Therefore, in comparison to DLS and heparin, it seems that the anticoagulant activity of DAS has a long duration.

Differential effects of chondroitin sulfates A and B on monocyte and B-cell activation: evidence for B-cell activation via a CD44-dependent pathway

At inflammatory sites, proteoglycans are both secreted by activated mononuclear leukocytes and released as a consequence of extracellular matrix degradation. Chondroitin 4-sulfate proteoglycans constitute the predominant ones produced by activated human monocytes/macrophages. In this study, we show that two chondroitin 4-sulfate forms, CSA and CSB, can activate distinct peripheral blood mononuclear cell types. Whereas CSA activates monocytes (to secrete monokines), CSB activates B-cells (to proliferate). In contrast, the chondroitin 6-sulfate CSC and heparin do not exert these functional effects. We further show that CD44 monoclonal antibodies block CSB-induced B-cell proliferation. These findings point to glycosaminoglycans, and specifically chondroitin 4-sulfates, as a novel class of immunological mediators at inflammatory sites. Furthermore, the data link CD44 to B-cell activation, paralleling the established roles of CD44 in T-cell and monocyte activation.

Chitosan-chondroitin sulfate and chitosan-hyaluronate polyelectrolyte complexes: biological properties

In this work, we compare some biological properties of a highly deacetylated chitosan to those obtained with the materials made from its polyelectrolyte complexes with various GAG's such as chondroitin-sulfates and hyaluronic acid. The hydrolysis of the complexes by means of the specific hydrolytic enzymes is studied. Cell-adhesion and cell-proliferation on these materials is compared to that obtained with a pure chitosan material. Finally, a series of in vivo experiments is performed to test the wound-healing properties of this kind of complexes. All the results agree to show that chitosan has a protective effect against GAG's hydrolysis by their specific enzymes but only at pH's different from the optimal pH of the enzyme considered. In addition, they also agree to confirm that a pure chitosan material gives the best results in connection with cell-attachment and cell-proliferation or wound healing. Nevertheless, whatever the case, no adverse effect was observed with the polyelectrolyte complexes GAG's-chitosan.

Protective effect of exogenous chondroitin 4,6-sulfate in the acute degradation of articular cartilage in the rabbit

The injection of 2.0 mg chymopapain into the adolescent rabbit knee causes severe loss of articular cartilage proteoglycans (PG). Although chondrocytes attempt to restore lost PG, failure to repair ensues. Pure chondroitin 4,6-sulfate (Condrosulf, IBSA Lugano, Switzerland) has been used in clinical studies of human osteoarthritis (OA) as a slow-acting drug for OA (SYSADOA). Using our model of articular cartilage injury, we examined the effects of oral and intramuscular administration of Condrosulf after chymopapain-induced cartilage injury. In this study, animals received an injection of 2.0 mg chymopapain (Chymodiactin, Boots Pharmaceuticals) into the left knee and were sacrificed after 84 days. The contralateral right knee served as a noninjected control. Some animals received oral Condrosulf while others received intramuscular injections of Condrosulf. Serum keratan sulfate (KS) levels were monitored to ensure degradation of the cartilage PG. Those animals not exhibiting at least a 100% increase of serum KS following chymopapain injection were excluded from the study. At sacrifice, cartilage PG contents were markedly reduced in animals receiving an injection of 2.0 mg chymopapain with no further treatment. In contrast, oral administration of Condrosulf beginning 11 days prior to chymopapain injury resulted in significantly higher (P = 0.0036) cartilage PG contents. Intramuscular administration of Condrosulf resulted in higher, but less significantly so (P = 0.0457), cartilage PG contents. These results suggest that daily Condrosulf treatment prior to and continuing after chymopapain injury may have a protective effect on the damaged cartilage, allowing it to continue to re-synthesize matrix PG after the treatment is discontinued.

Effects of chondroitin sulfate and interleukin-1 beta on human articular chondrocytes cultivated in clusters

OBJECTIVE

To test the effects of chondroitin sulfate (ACS, a glycosaminoglycan of cartilage) with and without interleukin-1 beta (IL-1 beta) on human articular chondrocytes cultivated in clusters and in long-term (0-16 days or 16-32 days).

DESIGN

Chondrocyte productions of proteoglycans (PGs), type II collagen (coll-II) and prostaglandin E2 (PGE2) were assayed by specific radioimmunoassays applied to conditioned culture media and to clusters.

RESULTS

During the two culture periods (0-16 days or 16-32 days), ACS (100-1000 micrograms/ml) increased total PG production and had no effect on the production of coll-II by chondrocytes. During the first 16 days, ACS (500-1000 micrograms/ml) decreased total PGE2 synthesis. IL-1 beta decreased PG and coll-II productions and increased PGE2 synthesis. During the first period (0-16 days), while the cluster is forming, ACS counteracted the IL-1 beta-induced effects on PG (500-1000 micrograms ACS/ml), coll-II (100-1000 micrograms ACS/ml) and PGE2 (500-1000 micrograms ACS/ml) productions. During the second period (16-32 days), when the cluster is already formed, ACS counteracted the IL-1 beta-induced effects on total PG (100-1000 micrograms ACS/ml), coll-II (1000 micrograms ACS/ml) and PGE2 (1000 micrograms ACS/ml) productions.

CONCLUSION

These in vitro studies suggest that ACS is able to increase matrix component production by human chondrocytes and to inhibit the negative effects of IL-1 beta.