Structure of hyaluronic acid in synovial fluid and its influence on the movement of solutes

Injectable polysaccharide hydrogels as localized nitric oxide delivery formulations

A series of injectable polysaccharide hydrogels were prepared with oxidized dextran and diethylenetriamine-modified carboxymethylcellulose or hyaluronic acid. Rheological evaluation revealed that carboxymethylcellulose-based hydrogels achieved the largest storage moduli (>1 kPa) when prepared from 5 wt. % solutions. However, carboxymethylcellulose-based hydrogels with storage moduli >100 Pa were prepared from solutions with concentrations as low as 2 wt. %. Hyaluronic acid-based hydrogels demonstrated smaller storage moduli but had swelling ratios more than four times that of the carboxymethylcellulose systems at the same polymer concentrations. The incorporation of N-diazeniumdiolate NO donors into the hydrogels resulted in reduced hydrogel storage moduli as a function of NO donor concentration. The impact of the hydrogel architecture on NO-release kinetics proved dependent on the identity of the NO donor. Hydrogel degradation over 14 d was measured at pH 5.4 and 7.4 and indicated that hyaluronic acid-based hydrogels degraded more rapidly than carboxymethylcellulose hydrogels and that the addition of NO to the hydrogels increased the rate at which they degraded. In vitro cytotoxicity of hydrogel extracts was evaluated against five cell lines, with no observed toxicity except for that of hyaluronic acid-based hydrogel extracts against human gingival fibroblasts. The diverse properties, versatility, and non-toxic characteristics of these injectable hydrogels should facilitate local delivery of nitric oxide for a range of biomedical applications.

Hyaluronic Acid as a Modern Approach in Anticancer Therapy-Review

Hyaluronic acid (HA) is a linear polysaccharide and crucial component of the extracellular matrix (ECM), maintaining tissue hydration and tension. Moreover, HA contributes to embryonic development, healing, inflammation, and cancerogenesis. This review summarizes new research on the metabolism and interactions of HA with its binding proteins, known as hyaladherins (CD44, RHAMM), revealing the molecular basis for its distinct biological function in the development of cancer. The presence of HA on the surface of tumor cells is a sign of an adverse prognosis. The involvement of HA in malignancy has been extensively investigated using cancer-free naked mole rats as a model. The HA metabolic components are examined for their potential impact on promoting or inhibiting tumor formation, proliferation, invasion, and metastatic spread. High molecular weight HA is associated with homeostasis and protective action due to its ability to preserve tissue integrity. In contrast, low molecular weight HA indicates a pathological condition in the tissue and plays a role in pro-oncogenic activity. A systematic approach might uncover processes related to cancer growth, establish novel prognostic indicators, and identify potential targets for treatment action.

Instillation of Hyaluronic Acid via Electromotive Drug Administration Can Improve the Efficacy of Treatment in Patients With Interstitial Cystitis/Painful Bladder Syndrome: A Randomized Prospective Study

PURPOSE

In the treatment of interstitial cystitis, intravesical hyaluronic acid application may be suggested as a treatment option. In this randomized prospective study, the authors aimed to identify whether instilling the hyaluronic acid with electromotive drug administration (EMDA) would increase the tissue uptake and improve the efficacy.

MATERIALS AND METHODS

The data of 31 patients who had been diagnosed with bladder pain syndrome/interstitial cystitis (BPS/IC) between 2004 and 2005 were examined. The patients were randomized to two groups: patients in group A received hyaluronic acid directly with a catheter and patients in group B received hyaluronic acid with EMDA. The patients were followed for 24 months and the two groups were compared at certain time intervals. The primary end points of the study were visual analogue scale (VAS) score, global response assessment, and micturition frequency in 24 hours.

RESULTS

There were 6 males and 25 females. The two groups were similar in baseline parameters. The decrease in VAS score and the micturition frequency in 24 hours were significantly lower with EMDA at months 6 and 12. The difference between the two groups was not significant at months 1 and 24. Also, treatment with EMDA, positive KCl test, and pretreatment voiding frequency >17 were associated with higher response rates.

CONCLUSIONS

Hyaluronic acid installation is an effective glycosaminoglycan substitution therapy in patients with BPS/IC. Instillation of hyaluronic acid via EMDA can improve the efficacy of the treatment; however, lack of long-term efficacy is the major problem with this glycosaminoglycan substitution therapy.

Sequential hydrodistension and intravesical instillation of hyaluronic acid under general anaesthesia for treatment of refractory interstitial cystitis: a pilot study

Pilot study looking at the combination of general anaesthetic hydrodistension and intravesical hyaluronic acid for treatment of refractory interstitial cystitis. Twenty-three treatment refractory patients were recruited with an average age 53.4 years. All underwent general anaesthetic cystoscopy, hydrodistension and instillation of hyaluronic acid (40 mg/50 ml). The bladder was then subsequently drained with the patient awake. Two initial treatments were carried out a month apart and duration between treatments increased depending upon symptom response. In the responders, the average number of treatments was 6.6 (median 4.5), duration between treatments was 3.1 months (median 2.6) and follow-up 15.8 months (median 16). Seventeen patients (74%) responded with immediate improvement in symptoms. In all responders, healing of ulceration and resolution of inflammation occurred. Average anaesthetic bladder capacity increased in the responder group from an average of 492 ml (median 500 ml) to an average of 776 ml (median 700 ml). Our pilot data suggests sequential hydrodistension and hyaluronic acid treatment under general anaesthesia may be considered for resistant cases of interstitial cystitis, especially those that cannot tolerate the instillation procedure under local anaesthesia. Further prospective trials are required.

Hyaluronic Acid: An Effective Alternative Treatment of Interstitial Cystitis, Recurrent Urinary Tract Infections, and Hemorrhagic Cystitis?

OBJECTIVES

Hyaluronic acid is a protective barrier of the urothelium. A damaged glycosaminoglycan layer may increase the possibility of bacterial adherence and infection. This damage is proposed to be a causative factor in the development of interstitial cystitis, common urinary tract infections, and hemorrhagic cystitis due to posthematopoietic stem cell transplantation. The aim of this article was to review the available data regarding the use of hyaluronic acid as an alternative treatment of the above-mentioned conditions.

METHODS

Articles relevant to our review that were archived by September 2006 were retrieved from PubMed.

RESULTS

Nine relevant studies were identified and evaluated. Hyaluronic acid was administered intravesically at a dose of 40 mg every week for 4-6 wk; patients with noted improvement received two additional monthly doses. Short-term responses of patients with interstitial cystitis, hemorrhagic cystitis, and recurrent urinary tract infections were 30-73% (7 studies), 71% (1 study), and 100% (1 study), respectively. The treatment was well tolerated except for occasional development of bacterial cystitis. The cost of each intravesical installation of hyaluronic acid is 120 UK pounds (excluding the cost of the urinary catheterization).

CONCLUSIONS

The available clinical data regarding the effectiveness of hyaluronic acid as a potential treatment of patients with interstitial cystitis, recurrent urinary tract infections, and hemorrhagic cystitis are limited. There is need for randomized controlled trials for further investigation of this important therapeutics question; these clinical trials should be disease-specific, blinded, and controlled, and of a sufficient number of patients. Until such studies are available, intravesical instillation of hyaluronic acid cannot be unquestionably endorsed for use for the aforementioned diseases.

Synovial fluid markers in osteoarthritis

Exploration of the mechanisms responsible for breakdown and repair of articular cartilage in osteoarthritis has promoted interest in the potential use of cartilage-derived molecules as markers of cartilage metabolism in this disease. Many of the macromolecules detectable in synovial fluid have been evaluated as possible surrogate markers of the severity or activity of disease processes. Measurements of the synovial fluid concentration of any marker without due consideration of the fate of the molecule in the joint cavity are likely to be misleading and insufficient to cement a relationship between marker concentration and the severity of articular pathology.

Effects of hyaluronan viscous materials on cell membrane electrical properties

Hyaluronan [hyaluronic acid (HA)] has been implicated in various cellular processes such as proliferation, adhesion, migration, and differentiation. The secondary and tertiary structures of HA give it very important and unique viscoelastic properties. HA-composed materials are currently used intraocularly during ophthalmological surgery to facilitate surgical procedures and prevent tissue damage. To examine the effects of three viscous biomaterials composed of hyaluronan (Healon, IAL, and Biolon) used in ophthalmological surgery, the membrane electrical properties of the erythroleukemic K562 cell line exposed to these materials were investigated. Membrane conductivity, membrane permittivity, and the conductivity of the cytosol were evaluated using dielectric relaxation measurements in the radiofrequency range and fitting the experimental results to the general equations of the Maxwell-Wagner effect. The results demonstrate that while membrane permittivity and the conductivity of the cytosol are not significantly altered, the membrane conductivity of K562 cells exposed to all three biomaterials increases substantially and in a time-dependent manner with respect to untreated cells. These observations seem to indicate that hyaluronan perturbs ionic transport while it does not vary the type, quantity, or distribution of membrane components. In addition, the variations induced by these substances on the cell membrane are not dependent upon the molecular weight or on the biological origin of hyaluronan. These results may aid in elucidating the mechanisms involved in hyaluronan/cell membrane interaction and thus may provide a deeper understanding of the complications related to their use in ophthalmological surgery.

Synthesis and release of hyaluronic acid by Swiss 3T3 fibroblasts

Hyaluronic acid (HA) and its synthesis were studied in intact Swiss 3T3 mouse fibroblasts and isolated membranes. HA chains in culture medium, attached to cells and in isolated membranes, were determined to possess average M(r) values of 5.2 x 10(6), 1.8 x 10(6) and 0.14 x 10(6) respectively. Log cells were determined to possess 680,000 HA molecules/cell, and to release 120,000 HA chains/h. The time required for intact cells to synthesize and release a complete HA chain was approximately 4 h, with elongation proceeding at a rate of 57 dimers/min. The amount of cell-associated HA of various cell populations correlated strongly with their rate of HA release into culture media and with the HA synthetase activity determined for their membranes. Prevention of protein synthesis with cycloheximide decreased the rate of HA synthesis of log cells and HA synthetase activity of isolated membranes by 50% within 2-3 h. Because of the similarity between the biological lifetime of HA synthetase and the time required to synthesize a HA chain, we propose a model where each synthetase makes only one HA chain; after synthesis of a complete HA chain, HA synthetase activity is terminated as its HA chain is released from the cell.

13C NMR investigation of synovial fluids

13C NMR spectra of synovial fluids from 20 patients suffering from rheumatic diseases have been recorded. Structural changes in hyaluronic acid, the main carrier of the viscoelastic properties of synovial fluid, could be observed in the NMR spectra of the native biological fluid. By comparing these spectra with those of purified hyaluronic acid, a rough estimation of the degree of depolymerization of synovial hyaluronic acid was possible. The patients with rheumatoid arthritis appeared to have a lower degree of polymerization compared to patients with osteoarthrosis. Thus, 13C NMR spectroscopy provides useful information about biophysical properties of synovial fluid.

Effect of hylan on cartilage and chondrocyte cultures

The protective role of hylan, a hyaluronan [hyaluronic acid (HA)] derivative, was studied in explanted bovine cartilage and isolated chondrocytes. Cartilage and chondrocytes were exposed to degradative enzymes (lysate from activated polymorphonuclear leukocytes), oxygen-derived free radicals (ODFR), conditioned media from mononuclear cells (MCCM), and interleukin-1 (IL-1), in the presence and absence of hylan. The effect of HA was also studied. In cartilage explants susceptibility to pertubation was evaluated in terms of 35S release and proteoglycan depletion and was compared to control cultures; high viscosity hylan was found to reduce 35S release in cartilage explants caused by degradative enzymes, ODFR, MCCM, and IL-1. The hylan effect was reversible and viscosity-dependent. In chondrocyte cultures, high viscosity hylan was effective in reducing cell injury caused by degradative enzymes and ODFR. The data suggest that the glycosaminoglycan hylan, as well as native HA, may mediate exposure to and/or response to stimuli associated with initiation of degenerative processes in cartilage tissues.

Changes in the viscosity of hyaluronic acid after exposure to a myeloperoxidase-derived oxidant

Both purified hyaluronic acid (HA) and bovine synovial fluid react with OCI-, the major oxidant produced by the myeloperoxidase (MPO)/H2O2/CI- system, resulting in a decrease in their specific viscosity. This reaction is inhibited in the presence of excess methionine. H2O2 alone decreases the viscosity of HA, presumably by the Fenton reaction, in the absence (but not in the presence) of the iron chelator, diethyltriaminepentacetic acid (DETAPAC). In the presence of DETAPAC, incubation of HA with the complete MPO/H2O2/CI- system lowered the viscosity of HA. Analysis of 3H-HA exposed to OCI- by gel filtration chromatography indicated that cleavage of HA occurred only at higher OCI- concentrations. We suggest that the reduction in viscosity of HA by the MPO/H2O2/CI- system may be due to a combination of oxidative cleavage and changes in the conformation of the molecule. We speculate that the changes in the molecular size of rheumatoid synovial fluid HA may be due to the action of the neutrophil MPO/H2O2/CI- system.

Transient solute diffusion in articular cartilage

The one-dimensional transient diffusion of glucose, inulin and dextran into adult bovine knee articular cartilage was determined for transport times of 1, 5, 15 and 60 min, and 4, 12, 24 and 48 h. The apparent diffusion coefficient and apparent interface partition coefficient were calculated from the concentration-depth profiles within the tissue using a theoretical model for non-steady state solute diffusion. The diffusion coefficient was found to decrease with both solute size and transport time. The partition coefficient also decreased with solute size but increased with transport time. Neither coefficient was dependent on normal tissue fluid or proteoglycan content variations.

Degradation of hyaluronic acid by polymorphonuclear leukocytes

Degradation (depolymerization) of hyaluronic acid is readily accomplished by superoxide-ion-generating systems, especially those which beget secondary free radicals. It has been presumed, but not confirmed, that this is the mechanism by which neutrophils might alter synovial fluid viscosity. We have demonstrated, in a neutrophil (PMN) superoxide system, physical disruption of the hyaluronate macromolecule using column chromatography and by measurement of intrinsic viscosity. In addition, comparison of calibrated free radical fluxes between a cell-free superoxide system and a neutrophil system revealed very close parallels in iron requirement, inhibition by free radical scavengers, and magnitude of effect. It is concluded that oxygen-derived free radicals are probably the major, if not sole, mechanism by which neutrophils might degrade hyaluronate.

Molecular weight distribution of hyaluronic acid of human synovial fluid in rheumatic diseases

New methods to isolate and characterize the molecular weight distribution of hyaluronic acid have been applied to human synovial fluids from arthritic patients. Considerable variations in molecular weight distribution were found between the individual fluids. These methods facilitate a detailed characterization of hyaluronic acid--a prerequisite for understanding the role of hyaluronic acid for normal joint function and to evaluate the therapeutic use of local application in joint diseases.

Ultrastructure of a hyaluronic acid matrix

Freeze-etch replicas of a hylauronic acid matrix were visualized by electron microscopy. In water a coarse branching fibrillar network of hyaluronic acid aggregates was seen. The high solvent permeability of this matrix suggests that the spaces observed are relatively devoid of unaggregated polymer. Addition of calcium disordered the matrix, resulting in a more dispersed felt of polymer.

Permeability of hyaluronic acid solutions. The effects of matrix concentration, calcium, and pH

The permeability of hyaluronic acid solutions was measured in a chamber closed at each end of semi-permeable membranes. Permeability was strongly concentration dependent below 1.0 gm% hyaluronic acid. Small changes in the ionic environment of 1.0 gm% hyaluronic acid solutions also altered permeability. The permeability of such solutions decreased by a factor of 4.7 in the presence of as little as 5 mM calcium ion and showed optimum permeability at pH 7.0. The pH optimum was not noted in hyaluronic acid preparations known to contain only small amounts of protein.

Synovial fluids facilitate small solute diffusivity

The diffusivity of water, fucose, proline, lysine, glutamic acid, glucose and sucrose was determined in a variety of inflammatory human synovial fluids. In view of the constituents of pathological synovial fluids one would predict impedence to solute movement. In several fluid diffusivity was enhanced relative to translational diffusion in water. In most fluids diffusivity was enhanced relative to diffusion in diluted serum. Diffusivity of the solutes was dependent on size and charge of the solute but independent of fluid characteristics, including glucose, protein, and complement concentrations and cellular constituents. This paper reports aberrant small solute behaviour in synovial fluids. Enhanced diffusivity relative to water was demonstrated in hyaluronate dissolved in diluted serum as well. Hyaluronate domains in the synovial fluids interact with these solutes, facilitating movement. This phenomenon affords a homoestatic mechanism as regards chondrocyte viability in spite of inflammation or a low glucose concentration.

Synovial permeability in rheumatoid arthritis

In patients with rheumatoid arthritis, as well as in persons with other kinds of synovitis, proteins enter the knee joint more rapidly than in normal individuals (P less than 0.001). The rheumatoid synovium, however, is less permeable to small molecules (tritiated water, P less than 0.02; urate, P less than 0.05; and glucose, P less than 0.002) than is the normal joint lining. This difference is explained if rheumatoid microvascular changes enhance synovial permeability to proteins while coexisting interstitial changes diminish synovial permeability to smaller molecules.