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Results for “HYALURONIC ACID”

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PubMed1993

Identification of hyaluronic acid binding sites in the extracellular domain of CD44.

CD44 is a polymorphic glycoprotein expressed on the surface of many tissues and cell lines which has been implicated in a number of cellular functions including lymphocyte homing to mucosal lymphoid tissue (Peyers patches), leukocyte activation, lymphopoiesis, and tumor metastasis. The predominant isoform found on human leukocytes, CD44H, is a receptor for hyaluronic acid. Because of the prominent role CD44 plays in diverse biological processes, we set out to identify the hyaluronic acid binding site(s) in the extracellular domain of CD44H. Using truncation and site-directed mutagenesis we identified two regions containing clusters of conserved basic residues which are important in hyaluronic acid binding. One of these regions is situated near the NH2 terminus and is homologous to other hyaluronic acid binding proteins including cartilage link protein. The other more membrane proximal region lies outside the link protein homologous domain. Mutagenesis of basic residues within these regions established their role as determinants in hyaluronic acid binding. Mutation of Arg 41, a position where a basic residue is conserved in all hyaluronic acid binding proteins, completely abolished binding suggesting that this residue plays a critical role in hyaluronic acid binding.

Amino Acid Sequence↗

PubMed1977

Synthesis of proteoglycans by suspension and monolayer cultures of adult chondrocytes and de novo cartilage nodules-the effect of hyaluronic acid.

Chondrocytes were isolated from adult laryngeal cartilage by an enzymic procedure that included 6 h digestion with collagenase. The level of 35SO4(2-) incorporation into cetylpyridinium chloride-precipitable material by these cells depended upon the subsequent culturing conditions. Suspension cultures incorporated more 35SO4(2-)/cell than monolayer cultures. Hyaluronic acid in the medium inhibited 35SO4(2-) incorporation only when the cells were in primary suspension cultures. It had no effect on monolayer cultures, or monolayers organized into nodules, or suspension cultures derived from monolayers. Mild pretreatment with EDTA, however, rendered these susceptible to hyaluronic acid inhibition. In contrast EDTA abolished the inhibitory effect of hyaluronic acid on primary suspension cultures. Oligosaccharides, derived from hyaluronidase digestion of hyaluronic acid that were larger than decassaccharide, had some inhibitor effect on 35SO4(2-) incorporation by monolayer cultures. The total 35SO4(2-) incorporation was less in primary suspension cultures of chondrocytes isolated after 12 h than after 6 h digestion of cartilage and the inhibition by hyaluronic acid was also less. These differences persisted during 12 days of culture. It is suggested that the method of isolating chondrocytes and subsequent culture conditions may modify the cell surface and mask or abolish specific binding sites for hyaluronic acid.

Animals↗

PubMed1992

CD44 can be activated to function as an hyaluronic acid receptor in normal murine T cells.

The hyaluronic acid (HA)-binding function of CD44 expressed on the cell surface of normal hematopoietic cells has been studied by assaying binding of fluoresceinated hyaluronic acid (F1-HA) and adhesion to immobilized HA. As has been observed previously, normal hematopoietic cells from bone marrow and spleen do not constitutively bind HA. A CD44-specific monoclonal antibody, IRAWB 14, which has been shown to rapidly induce HA binding in some CD44+ cell lines, was used to activate the HA-binding function of CD44 in these normal cells. Only splenic T cells were activated by the IRAWB 14 antibody to bind F1-HA. Upon activation, F1-HA binding correlated with the level of CD44 expression. Activation of HA binding allowed splenic T cells to adhere to HA immobilized on plastic and to an endothelial cell line in an HA-dependent manner. BALB/c and AKR/J splenic T cells differ in their level of CD44 expression, and this correlated with differences in their ability to bind HA upon antibody activation. The minor subpopulation of MEL-14- T cells were among the brightest F1-HA-staining cells. We propose, on the basis of these and other results, that there are three states of CD44 function with respect to HA binding: (a) a non-activatable, resting state, which cannot be rapidly activated to bind HA, as seen in most hematopoietic cells; (b) an activatable state, which can be rapidly converted to HA-binding function, in this case by the IRAWB 14 antibody, illustrated by T cells as shown here; and (c) a constitutively active state, which can bind HA without antibody activation, seen in some cell lines.

Animals↗

PubMed2001

Serum hyaluronic acid in patients with veno-occlusive disease following bone marrow transplantation.

The development of hepatic veno-occlusive disease following bone marrow transplantation is associated with high-dose combination cytoreductive therapy. Experimental models have suggested that drug-induced injury to hepatic sinusoidal endothelial cells is involved in the pathogenesis of this syndrome. Hyaluronic acid is a polysaccharide that is metabolized, almost exclusively, by hepatic sinusoidal endothelial cells. The aim of the present study was to evaluate serum hyaluronic acid as a marker for endothelial cell injury in patients with veno-occlusive disease following bone marrow transplantation. Hyaluronic acid was measured in sera from patients with and without veno-occlusive disease using an enzyme-linked protein binding assay. Mean peak serum hyaluronic acid levels were significantly greater in patients who had a diagnosis of VOD compared to those transplant patients who did not, 1173.4 +/- 982.9 vs 444.9 +/- 735.6 ng/ml (P = 0.01). Serial serum samples obtained from a separate cohort of patients also demonstrated that serum hyaluronic acid levels were higher in patients with moderate or severe veno-occlusive disease compared to those with none or mild disease at days 7, 17 and 25 following transplantation (greatest difference at day 25: 366 +/- 327 vs 126 +/- 151, P = 0.01). Serum hyaluronic acid levels are increased in veno-occlusive disease and increase over time in patients with severe disease. Further studies are required to determine if elevated serum hyaluronic acid levels are due to decreased clearance by injured hepatic sinusoidal endothelial cells or increased production from early hepatic fibrogenesis associated with the acute liver injury.

Adult↗

PubMed1989

Molecular weight dependence of hyaluronic acid produced during oncogenic transformation.

Cultured chicken embryo fibroblasts synthesize two distinct molecular size classes of hyaluronic acid. The high molecular weight material (form I, 2.98 x 10(6) is the predominant species synthesized by transformed cells, whereas form II (1.42 x 10(5)) is the major product of non-transformed cells. A shift to synthesis of predominantly form I hyaluronic acid is an early transformation event in cells infected with LA24 Rous sarcoma virus and maintained at the permissive temperature for transformation (35 degrees C). Form I hyaluronic acid exhibits greater binding to preparations of cellular fibronectin and to both normal and transformed cells than does form II. Both forms bind more to transformed cells than to normal, uninfected cells. Hyaluronic acid (predominantly form I) isolated from transforming cells stimulates proliferation in growth-retarded, non-transformed cells.

Animals↗

PubMed2005

Hyaluronic acid, an accurate serum marker for severe hepatic fibrosis in patients with non-alcoholic fatty liver disease.

AIM: To determine whether serum hyaluronic acid reliably predicts the severity of hepatic fibrosis in patients with non-alcoholic fatty liver disease (NAFLD). METHODS: We studied 79 patients with histologically confirmed NAFLD. Hyaluronic acid was measured in serum obtained at the time of liver biopsy. Severity of fibrosis was staged based on Brunt's classification. The prediction levels for fibrosis were determined by area under the receiver operating characteristic curve (AUC). RESULTS: The logarithm of serum hyaluronic acid was significantly different among the stages of fibrosis (P<0.0001, analysis of variance) and had a significant positive correlation with the degrees of fibrosis after adjusting for age and serum albumin (partial r=0.44, P<0.0001). AUCs were 0.67, 0.87, 0.89, and 0.92 for any levels of fibrosis, > or =moderate fibrosis, > or =severe fibrosis, and cirrhosis, all of which were significantly higher than 0.5 (P<0.05). The cut-off value of serum hyaluronic acid of 46.1 mug/l was associated with the highest AUC for severe fibrosis, yielding a sensitivity of 85% and a specificity of 80%. The corresponding positive and negative predictive values were 51% and 96%, when assuming prevalence of severe fibrosis in NAFLD patients of 20% at referral centers. CONCLUSIONS: Measurement of serum hyaluronic acid is useful to identify NAFLD patients with severe fibrosis.

Adult↗

PubMed1999

Amyotrophic lateral sclerosis: increased hyaluronic acid in the media of the basilar artery.

Hyaluronic acid in the basilar artery of 10 patients with sporadic amyotrophic lateral sclerosis (ALS) and 7 age-matched control subjects was examined histochemically and densitometrically. The intensity of staining with alcian blue was significantly increased (P=0.0007) in the media in ALS patients compared with that in control subjects. The staining was virtually eliminated by Streptomyces hyaluronidase. These results clearly indicate an increase of hyaluronic acid in the media of the basilar artery in ALS patients.

Aged↗

PubMed1987

Glycosaminoglycan stimulation of calcium release from mouse calvariae. Specificity for hyaluronic acid and dermatan sulfate.

Heparin in combination with suboptimal concentrations of parathyroid hormone (PTH) has been shown to stimulate calcium release from bone organ cultures. The mechanism of action of heparin, however, is not known. One possible mechanism relates to the highly sulfated structure of heparin. We have compared heparin to other glycosaminoglycans to stimulate calcium release from mouse calvarial organ cultures in the presence and absence of suboptimal concentrations of parathyroid hormone. The exogenous addition of heparin to bone cultures demonstrated only slight effects on calcium release at 5.0, 10, and 100 micrograms/ml. The addition of hyaluronic acid to the calvarial cultures caused a significant release of calcium at 10 and 100 micrograms/ml compared to 5 micrograms/ml hyaluronic acid. Dermatan sulfate was equally as effective as hyaluronic acid at 100 micrograms/ml but not at 10 micrograms/ml. A comparison of heparin- and hyaluronic acid-stimulated release demonstrated a significantly greater amount of calcium release with hyaluronic acid 100 micrograms/ml. At 5.0 and 10 micrograms/ml, there was no difference between heparin and hyaluronic acid in the amount of calcium released into the culture medium. When heparin was added to the organ cultures with suboptimal concentrations of PTH, there was a significant enhancement of calcium release observed with 10 and 100 micrograms/ml heparin compared to heparin addition alone. When hyaluronic acid was added with suboptimal concentrations of PTH, no significant enhancement of calcium release was observed with 100 micrograms/ml hyaluronic acid. Dermatan sulfate, chondroitin sulfates A and C, and keratan sulfate, in combination with PTH, stimulated significant calcium release compared to the glycosaminoglycan added alone.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1980

Effect of hyaluronic acid on phagocytosis of opsonized latex particles.

In an in vitro model system using isolated human granulocytes high molecular weight hyaluronic acid stimulated the initial rate of phagocytosis of complement-opsonized latex particles. This specific quality was dependent on the molecular size and occurred at low concentrations (1-10 mg/l) of hyaluronic acid. However, at high concentrations (> 100 mg/l) hyaluronic acid inhibited the initial rate of phagocytosis of both IgG- and complement-opsonized particles. The latter effect was shared with chrondoitin sulphate, heparan sulphate and heparin. The results suggest that hyaluronic acid may be instrumental in controlling inflammatory processes.

Chondroitin Sulfates↗

PubMed2005

Increase in hyaluronic acid production by Streptococcus equi subsp. zooepidemicus strain deficient in beta-glucuronidase in laboratory conditions.

Streptococcus equi subsp. zooepidemicus is known to produce a hyaluronic acid capsule to resist the host immune defense. As the structure of the polysaccharide is identical to the one produced by humans, the bacteria S. equi subsp. zooepidemicus is used in biotechnological production of hyaluronic acid. In our laboratory we prepared mutated strains that are beta-glucuronidase deficient. Comparing the wild-type strain, which is positive in beta-glucuronidase activity, with the mutated strains named clone1 and clone2 in laboratory conditions, we observed that beta-glucuronidase influences the production of hyaluronic acid considerably and the molecular weight of hyaluronan slightly. The production of hyaluronic acid by the mutated strains is higher by approximately 20% and the molecular weight is larger by about 2%. The significant increase in the production of hyaluronic acid and the slight increase in the molecular weight are probably caused by an absence of free beta-glucuronic acid, due to its removal from the non-reducing termini of the polysaccharide by beta-glucuronidase. The presence of free beta-glucuronic acid would likely induce the expression of the beta-glucuronic-acid-utilizing operon, which in turn would reflect into a misuse of energy in the glucose-rich media.

Chromatography, Gel↗

PubMedDate not supplied

Effect of hyaluronic acid on corneal haze in a photorefractive keratectomy experimental model.

PURPOSE: To evaluate the ability of topical hyaluronic acid to decrease corneal opacity after excimer laser photorefractive keratectomy (PRK) in hens. METHODS: Twenty-four white hens underwent bilateral 193-nm excimer laser PRK to correct -9.00 D of myopia. One eye received postoperative treatment with topical 1% hyaluronic acid six times daily for 3 days; the other eye received phosphate buffered saline. Slit-lamp evaluation by a masked observer was performed for 6 months after PRK, and electron microscopy was carried out at the end of the study. RESULTS: There were no significant differences in postoperative haze between the eyes treated with hyaluronic acid and those treated with phosphate buffered saline. CONCLUSION: Topical administration of hyaluronic acid had no effect on the development of corneal haze following PRK in hens.

Administration, Topical↗

PubMed1999

Effect of hyaluronic acid on migration, proliferation and alpha-smooth muscle actin expression by cultured rat and human fibroblasts.

Hyaluronic acid represents a major constituent of the extracellular matrix and influences numerous cellular processes. We have studied the effect of this molecule on migration, proliferation and alpha-smooth muscle actin expression by rat and human cultured fibroblasts. Depending on the tissue origin of the fibroblasts, hyaluronic acid induced, inhibited or did not affect fibroblast migration, whereas proliferation was never affected. Alpha-smooth muscle actin expression was inhibited by hyaluronic acid in all types of human and rat fibroblasts studied, but the inhibition was stronger and dose dependent for subcutaneous fibroblasts and for those recovered from Dupuytren's nodules. This property of inhibiting alpha-smooth muscle actin expression makes hyaluronic acid a good candidate to exert antifibrotic activity.

Actins↗

PubMed1995

Hyaluronic-acid-deficient extracellular matrix induced by addition of 4-methylumbelliferone to the medium of cultured human skin fibroblasts.

The effects of xylosyl-beta-D-(4-methylumbelliferone) and its aglycone, 4-methylumbelliferone, on hyaluronic acid synthesis were investigated in cultured human skin fibroblasts. Xylosyl-beta-D-(4-methylumbelliferone) added to the medium of cultured cell reduced the synthesis of hyaluronic acid. Furthermore, 4-methylumbelliferone reduced the production of hyaluronic acid markedly. In addition, 4-methylumbelliferone had hardly any effect on proteoglycan synthesis, whereas xylosyl-beta-D-(4-methylumbelliferone) produced a large amount of glycosaminoglycan chains. The present results indicate that cells cultured with 4-methylumbelliferone produce a hyaluronic-acid-deficient extracellular matrix, which will be useful for functional studies of hyaluronic acid.

Cells, Cultured↗

PubMed1993

Separation of human spermatozoa with hyaluronic acid induces, and Percoll inhibits, the acrosome reaction.

The effect on the acrosome reaction of human spermatozoa of two widely used sperm separation media, hyaluronic acid (Sperm Select) and Percoll, was studied. Viable and highly motile fractions of human spermatozoa were separated from seminal plasma using self-migration on a Percoll gradient. After translocation of separated spermatozoa from the Percoll solution to a culture medium, serum, Percoll or hyaluronic acid (Sperm Select) was added to aliquots of the spermatozoa containing culture medium. At increasing time intervals, the influx of 45Ca2+ into spermatozoa was measured and the concentration of viable spermatozoa that had undergone the acrosome reaction was analysed using the triple stain technique. Serum was found to be necessary to support sperm motility and viability. Compared to culture medium with serum only, addition of hyaluronic acid induced influx of 45Ca2+ and the acrosome reaction, whilst Percoll inhibited both of these actions. Hyaluronic acid (Sperm Select) added to spermatozoa separated by a 'swim-up' method induced, and the addition of Percoll inhibited, influx of 45Ca2+ when compared to the addition of culture medium with serum only. This study demonstrates that both hyaluronic acid (Sperm Select) and Percoll affect the acrosome reaction and the prerequisite for Ca2+ influx in human spermatozoa. These effects should be taken into consideration when using these media for preparation of spermatozoa for insemination or for fertilization in vitro.

Acrosome↗

PubMed2005

Apoptosis and nitric oxide in an experimental model of osteoarthritis in rabbit after hyaluronic acid treatment.

OBJECTIVE: this study determine the effect of hyaluronic acid on chondrocyte apoptosis, as well as variations in nitric oxide levels in an experimental model of osteoarthritis elicited anterior cruciate ligament section (ACL) in a rabbit model with two differentiated developmental periods. METHODS: apoptosis and the quantification of nitric oxide (NO) were studied in two groups of 16 animals each. All animals had both knees operated, but only the right knees were treated with hyaluronic acid (HA). In the first group hyaluronic treatment was performed five weeks after osteoarthritis induction (short term group, ST) and in the second group, 10 weeks after induction (long term group, LT). The animals in both series were sacrificed two weeks after the last dose of HA. Flow cytometry by means of Annexin labelling and the TUNEL method were used for the study of apoptosis, NO levels were measured in cultured cartilage and in the supernatant of the enzymatic digestion of the cartilage. RESULTS: regarding apoptosis measurement, a significant reduction in apoptosis levels was observed in both series as compared to untreated knees. NO production was lower in knees treated with HA, with significant differences after cartilage digestion. CONCLUSION: The administration of HA has been effective ameliorating the damage associated with the process of osteoarthritis induced by experimental surgery as evidenced by decreased apoptosis (TUNEL method), the results more promising in the earlier phases of the disease.

Animals↗

PubMed1990

Quantitation of hyaluronic acid and chondroitin sulphates in rabbit synovial fluid by high-performance liquid chromatography of oligosaccharides enzymatically derived thereof.

A high-performance liquid chromatographic (HPLC) method for quantifying unsaturated hexasaccharide and tetrasaccharide from Streptomyces hyaluronidase enzyme digestion products of hyaluronic acid was developed using a gel-permeation column packed with a sulphated polystyrene-divinylbenzene gel. For the oligosaccharides, the separation was accomplished in less than 7 min with a detection limit of 65 ng. An unsaturated non-sulphated disaccharide prepared from hyaluronic acid (delta Di-HA) and an unsaturated sulphated disaccharide (delta Di-4S) were analyzed by a HPLC method using a combination of two different gel-permeation columns. The separation of the disaccharides required less than 17 min at a flow rate of 0.7 ml/min with detection limits of as little as 4 ng for delta Di-HA and 5 ng for delta Di-4S. Both chromatographic methods were used for assay of a major component of hyaluronic acid and trace amounts of chondroitin sulphates in rabbit synovial fluid. The resulting contents of hyaluronic acid were compared to the values of polymeric hyaluronic acid directly measured by a HPLC method using two gel-permeation columns packed with a poly(hydroxyalkyl methacrylate) gel and the amounts of hyaluronic acid converted from uronic acid content determined by a colorimetric method.

Animals↗

PubMed1978

[The different effects of fe(II)- and fe(III)-ions on the hyaluronic acid of the vitreous body (author's transl)].

Fe(II)-ions reduce the viscosity of a hyaluronic acid solution but do not form a precipitate. Fe(III)-ions only slightly lower the viscosity of hyaluronic acid solutions but cause a brown, water-insoluble iron-hyaluronic acid precipitate. After adding ascorbic acid--concentrate the pH-value as in vitreous body--to the reaction solution, Fe(III)-ions reduce the viscosity too. The iron-hyalurnic acid complex is also destroyed by ascorbate. Therefore, the ascorbate of the vitreous humor plays an important role in the generation of siderosis bulbi.

Animals↗

PubMedDate not supplied

[Anti-inflammatory activity of hyaluronic acid].

The results of in vivo experiments showed that hyaluronic acid possesses antiexudative activity comparable with that of nonsteroidal anti-inflammatory drugs. Hyaluronic acid exhibits antagonism with respect to histamine-induced inflammation.

Animals↗