Effect of connective tissue intercellular matrix on lymphocyte stimulation

A Systematic Study of the Effect of Different Molecular Weights of Hyaluronic Acid on Mesenchymal Stromal Cell-Mediated Immunomodulation

Introduction

Osteoarthritis (OA) is associated with chronic inflammation, and mesenchymal stromal cells (MSCs) have been shown to provide pain relief and reparative effects in clinical investigations. MSCs are often delivered with hyaluronic acid (HA), although the combined mechanism of action is not fully understood; we thus investigated the immunomodulatory effects of combining MSCs with different molecular weights (MW) of HA.

Methods

HAs with MWs of 1.6 MDa (hHA), 150 kDa or 7.5 kDa, were added to MSCs alone or MSC-immune cell co-cultures. Gene expression analyses, flow cytometry and cytokine measurements were assessed to determine the effect of HAs on the MSC interactions with immune cells.

Results

MSCs in the presence of HAs, in both normal and lymphocyte-conditioned medium, showed negligible changes in gene expression. While addition of hHA resulted in increased proliferation of activated lymphocytes, both in the presence and absence of MSCs, the overall combined effect was a more regulated, homeostatic one; this was supported by higher ratios of secreted IL10/IFNγ and IL10/IL2, in lymphocyte cultures, than with lower MW HAs or no HA, both in the presence and absence of MSCs. In addition, examination of monocyte-derived macrophages showed an increased M2 macrophage frequency (CD14+CD163+CD206+) in the presence of hHA, both with and without MSCs.

Conclusions

hHA produces a less pro-inflammatory environment than lower MW HAs. Moreover, combining hHA with MSCs has an additive effect on the MSC-mediated immunomodulation, suggestive of a more potent combination treatment modality for OA.

Nanoincorporation of curcumin in polymer-glycerosomes and evaluation of their in vitro–in vivo suitability as pulmonary delivery systems

This work was aimed at deliver curcumin to lungs by its incorporation into innovative vesicles glycerosomes and polymer-glycerosomes, the latter obtained combining glycerosomes with two polymers: sodium hyaluronate and trimethyl chitosan.

Hyaluronan molecular weight distribution is associated with the risk of knee osteoarthritis progression

OBJECTIVE

We investigated the relationship between the molecular weight (MW) distribution of hyaluronan (HA) in synovial fluid (SF) and risk of knee osteoarthritis (OA) progression.

METHODS

HA MW was analyzed for 65 baseline knee SFs. At 3-year follow-up, knees were scored for change in joint space narrowing (JSN), osteophyte (OST) progression, or occurrence of total knee arthroplasty (TKA). HA MW distribution was analyzed using agarose gel electrophoresis (AGE), and its relationship to OA progression was evaluated using logistic regression. The association between HA MW and self-reported baseline knee pain was analyzed using Pearson's correlation coefficients.

RESULTS

Knee OA was categorized as non-progressing (OST-/JSN-, 26 knees, 40%), or progressing based on OST (OST+/JSN-, 24 knees, 37%), OST and JSN (OST+/JSN+, 7 knees, 11%) or total knee arthroplasty (TKA, 8 knees, 12%). The MW distribution of HA in baseline SFs was significantly associated with the odds of OA progression, particularly for index knees. After adjusting for age, gender, BMI, baseline X-ray grade and pain, each increase of one percentage point in %HA below 1 million significantly increased the odds of JSN (odds ratios (OR) = 1.45, 95% CI 1.02-2.07), TKA or JSN (OR = 1.24, 95%CI 1.01-1.53) and the odds of any progression (OR = 1.16, 95% CI 1.01-1.32). HA MW distribution significantly correlated with pain.

CONCLUSION

These data suggest that the odds of knee OA progression increases as HA MW distribution shifts lower and highlight the value of reporting MW distribution rather than just average MW values for HA.

Preparation of a hyaluronic acid hydrogel through polyion complex formation using cationic polylactide-based microspheres as a biodegradable cross-linking agent

A novel hyaluronic acid (HA)-based hydrogel was prepared through polyion complex (PIC) formation between cationic polylactide (PLA)-based microspheres (MS+) and hyaluronic acid (HA-) as an anionic polyelectrolyte. The MS+ and HA formed a biodegradable PIC hydrogel (HA-/MS+) when mixed in aqueous media. The swelling behavior and mechanical properties of the PIC hydrogel could be controlled by changing the charge ratio between HA- and MS+. In addition, the HA-/MS+ PIC hydrogel resulted in a lower inflammatory response compared with a collagen hydrogel in vivo.

Genome integrity, stem cells and hyaluronan

Faithful preservation of genome integrity is the critical mission of stem cells as well as of germ cells. Reviewed are the following mechanisms involved in protecting DNA in these cells: (a) The efflux machinery that can pump out variety of genotoxins in ATP-dependent manner; (b) the mechanisms maintaining minimal metabolic activity which reduces generation of reactive oxidants, by-products of aerobic respiration; (c) the role of hypoxic niche of stem cells providing a gradient of variable oxygen tension; (d)(e) the presence of hyaluronan (HA) and HA receptors on stem cells and in the niche; (f) the role of role of HA in protecting DNA from oxidative damage; (g) the specific role of HA that may play a role protecting DNA in stem cells; (h) the interactions of HA with sperm cells and oocytes that also may shield their DNA from oxidative damage, and (e) mechanisms by which HA exerts the anti-oxidant activity. While HA has multitude of functions its anti-oxidant capabilities are often overlooked but may be of significance in preservation of integrity of stem and germ cells genome.

The role of viscosupplementation in the ankle using hylan G-F 20

The use of intra-articular injections of high molecular weight elastoviscous solutions of hyaluronan or hylans (cross-linked derivatives of hyaluronan) to treat arthritis is termed viscosupplementation. The function of viscosupplementation is to restore the rheologic properties of synovial fluid. Although anecdotal data exist, no long-term studies regarding the use of viscosupplementation in the ankle have been published to date. The goal of this clinical trial was to compare pain reduction following ankle arthroscopy versus that following ankle arthroscopy combined with weekly intra-articular instillation of hylan G-F 20 during the first 3 postoperative weeks. In the series of patients described in this report, we found that both treatment groups experienced statistically significantly decreased pain following the intervention (P = .002 and P = .0009 for the arthroscopy alone and arthroscopy plus hylan groups, respectively), and that those who received 3 intra-articular injections of hylan G-F 20 following ankle arthroscopy improved statistically significantly (P = .0014) more than did those who underwent arthroscopy as a sole therapy. These preliminary results suggest that viscosupplementation combined with arthroscopy may be more beneficial than arthroscopy alone, and provide further insight into the role of viscosupplementation in the treatment of ankle osteoarthritis.

LEVEL OF CLINICAL EVIDENCE

4.

Interactions between cells of the immune system and hyaluronate synthesis by human dermal fibroblasts

Mitogen- or alloantigen-activated human peripheral blood mononuclear cells (MNC) produce a soluble factor which selectively stimulates up to twenty-fold the synthesis of glycosaminoglycan (GAG) by cultured normal human fibroblasts. Confluent fibroblast monolayers were incubated with active MNC supernatants and newly synthesized GAG was measured by the incorporation of [3H]glucosamine into cetylpyridinium chloride-precipitable material. The GAG-stimulatory factor (GAG-SF) was a product of T lymphocytes. Alloreactive T cell clones obtained from the peripheral blood produced the factor after reactivation with the irradiated stimulators, and its production was dependent on HLA-DR-mediated recognition. The CD3+CD4+ clones derived from the skin-infiltrating lymphocytes in patients with early scleroderma also produced the GAG-SF upon in vitro activation with a mitogen. The GAG-SF was purified to apparent homogeneity from supernatants of concanavalin A-activated MNC by Sephadex gel filtration, ion-exchange chromatography and reverse-phase HPLC. The GAG-SF is a 67,000 Da glycoprotein with pI of 5.6. It is not mitogenic to fibroblasts and does not modulate collagen synthesis. Its purification and characterization are important, because of a possible involvement of activated lymphocytes and their products in the immunopathogenesis of human diseases characterized by fibrosis, stromal reactions and local lymphocytic infiltrates.

Controlled drug delivery to the lung: Influence of hyaluronic acid solution conformation on its adsorption to hydrophobic drug particles

This work reports investigations into the interaction and adsorption of the hydrophilic polymer hyaluronic acid (HA) onto the surface of the hydrophobic corticosteroid drug fluticasone propionate (FP). The eventual aim is to formulate a bioadhesive pulmonary drug delivery system with prolonged action that avoids rapid clearance from the lungs by the mucociliary escalator. Adsorption isotherms detailing the adsorption of HA from aqueous HA solution concentrations ranging from 0.14 to 0.0008% (w/v) to a fixed FP particle concentration of 0.1% (w/v) were investigated. The method of preparing FP particles with HA molecules adsorbed on their surfaces (FP/HA particles) involved suspension of the FP either in hydrated HA solution or in water followed by addition of solid HA, centrifugation of the solids to form a pellet, washing the pellet several times with water until no HA was found in the supernatant and then freeze drying the suspension obtained by dispersing the final pellet. The freeze dried powder was then analysed for adsorbed HA using a Stains-all assay. The influence of order of addition of HA to FP, time for the adsorption process, and temperature of preparation on the adsorption isotherms was investigated. The non-equilibrium adsorption isotherms produced generally followed the same trend, in that as the HA solution concentration increased, the amount of HA adsorbed increased to a maximum at a solution concentration of approximately 0.1% (w/v) and then decreased. The maxima in the adsorption isotherms were close to the change from secondary to tertiary conformation in the HA solutions. Below the maxima, adsorption occurred via interaction of FP with the hydrophobic patches along the HA chains in the secondary structures. Above the maxima, secondary HA molecules aggregate in solution to form tertiary network structures. Adsorption from tertiary structure was reduced because strong interactions between the HA molecules limited the availability of hydrophobic patches for adsorption of HA onto FP. The influence of preparation variables on adsorption was also related to the availability of hydrophobic patches for adsorption.

Intra-articular hyaluronan therapy

Viscosupplementation, in which hyaluronan derivatives are injected into the intra-articular space of osteoarthritic joints, is now widely used to treat knee osteoarthritis (OA). No viscosupplements have been approved for osteoarthritic joints other than the knee. To date, no clinical trials using viscosupplements to treat ankle or foot OA have been published. However, the mechanisms thought to be responsible for viscosupplementation's therapeutic effects would likely apply in any synovial joint. A goal of this article is to stimulate interest in research to assess the potential role of viscosupplementation in treating foot and ankle OA.

Intra-articular hyaluronan (hyaluronic acid) and hylans for the treatment of osteoarthritis: mechanisms of action

Although the predominant mechanism of intra-articular hyaluronan (hyaluronic acid) (HA) and hylans for the treatment of pain associated with knee osteoarthritis (OA) is unknown, in vivo, in vitro, and clinical studies demonstrate various physiological effects of exogenous HA. HA can reduce nerve impulses and nerve sensitivity associated with the pain of OA. In experimental OA, this glycosaminoglycan has protective effects on cartilage, which may be mediated by its molecular and cellular effects observed in vitro. Exogenous HA enhances chondrocyte HA and proteoglycan synthesis, reduces the production and activity of proinflammatory mediators and matrix metalloproteinases, and alters the behavior of immune cells. Many of the physiological effects of exogenous HA may be a function of its molecular weight. Several physiological effects probably contribute to the mechanisms by which HA and hylans exert their clinical effects in knee OA.

Adhesion molecules

The exact mechanisms by which serous ovarian cancer cells invade through their underlying basement membrane or are released from the surface of the ovary have yet to be elucidated. This process undoubtedly has a complex molecular basis that most likely involves multiple cell surface receptors, basement membrane components, intercellular adhesion molecules, and signaling from the cell [137]. One possible mechanism by which ovarian carcinoma tumor cells may alter their basement membrane is by the synthesis and secretion of proteolytic enzymes that degrade their basement membranes [88-94, 138]. Alternatively, metastatic ovarian carcinoma cells may decrease their synthesis and/or secretion of ECM molecules. Additional studies are required to determine whether the more aggressive behavior of malignant ovarian carcinoma cells, compared to normal ovarian epithelial cells, is related to an altered cellular response towards ECM molecules, perhaps due to alterations in adhesion molecules/receptors. A further elucidation of the mechanisms by which serous ovarian carcinoma cells regulate their expression of ECM molecules and adhesion molecules/receptors will help in our understanding of the invasion and metastasis of tumor cells. Members of several families of adhesion molecules have been described that seem to be important in the progression of ovarian carcinoma, including CD44, integrins, and E-cadherin. Due to the complexity of this disease, it is likely that other adhesion molecules will also be implicated in the adhesion, migration, invasion, growth, proliferation, and apoptosis of ovarian carcinoma cells. Our group and others have shown that CD44 and the beta 1 integrin subunit play fundamental roles in the adhesion and migration of ovarian carcinoma cells to mesothelial cells and their associated pericellular matrix. Subsequent to the initial adhesion, the ovarian carcinoma cells may migrate through the layer of mesothelial cells, penetrate through the underlying basement membrane, invade into the tissue, and establish a secondary site of growth. Further studies will be required in order to fully understand the relationship of each adhesion molecule and their ligand(s) in the progression of this disease. Once the adhesion molecules and their ligand(s) for each step of the progression of this disease have been identified, it should be possible to develop reagents that can inhibit these interactions. Then, when ovarian carcinoma cells can no longer interact with mesothelial cells and their associated ECM, the dissemination of ovarian carcinoma cells in vivo may be prevented.

Intra-articular hyaluronan therapy

The hyaluronan in normal synovial fluid plays an important role in joint homeostasis. It contributes to joint lubrication, buffers load transmission across articular surfaces, provides a renewed source of hyaluronan to joint tissues, and imparts antinociceptive and anti-inflammatory properties to synovial fluid. In osteoarthritis, the molecular weight and concentration of hyaluronan in synovial fluid are diminished. This has led to the proposition that removal of pathologic osteoarthritic synovial fluid and replacement with hyaluronan-based products that restore the molecular weight and concentration of hyaluronan toward normal levels can have beneficial therapeutic effects. This form of treatment for osteoarthritis has been termed viscosupplementation. Within the musculoskeletal community there are diverse opinions, ranging from skepticism to acceptance, about viscosupplementation as a mainstream symptom-modifying osteoarthritis therapy. This review focuses on recent basic and clinical studies dealing with mechanism of action, symptomatic efficacy, safety, and disease modification, and places these studies in context with earlier studies.

A risk-benefit assessment of injections of hyaluronan and its derivatives in the treatment of osteoarthritis of the knee

Hyaluronan is critical for the homeostasis of the joint as an organ, in part, because it provides the rheological properties (viscosity and elasticity) of the synovial fluid. These properties depend upon both the concentration and the molecular weight of the hyaluronan in the synovial fluid. In osteoarthritis, the hyaluronan is both smaller in size and lower in concentration. Thus, it is rational and physiologically meaningful to treat osteoarthritis with viscosupplementation, i.e. injection of material designed to increase the rheological properties of the synovial fluid. It is important, though, to assess the risks and benefits of such a physiological treatment. There are various products on the market for viscosupplementation. These include hyaluronan preparations of relatively low molecular weight (Hyalgan and ARTZ), a hyaluronan preparation of intermediate molecular weight, but still lower molecular weight than that of the hyaluronan in normal healthy synovial fluid (Orthovisc), and a cross-linked hyaluronan (a hylan) of high molecular weight (Synvisc). The evidence from in vitro and in vivo models of osteoarthritis and from clinical trials to date suggests that efficacy, as would be expected by mechanistic reasoning, depends strongly upon molecular weight. The available evidence indicates that these products differ little in the incidence and severity of adverse events (about 2 to 4%, almost always local swelling, and with no adverse sequelae). All are very well tolerated in comparison to nonsteroidal anti-inflammatory drug therapy, although direct comparisons are few. The only potentially serious adverse event is joint infection, which is rare and directly dependent upon the number of injections, among other factors. No infection has been related to contamination of any of the products. In summary, treatment with low molecular weight preparations of hyaluronan seems to be effective. However, viscosupplementation with hyaluronan preparations may have slightly higher risk and less benefit than viscosupplementation with hylans, because the relatively lower molecular weight hyaluronan preparations require more injections which may incur higher costs and theoretically an increased chance of infection. Viscosupplementation with hylans is clearly effective, and the available evidence suggests that the benefits almost certainly outweigh the risks.

Reduction of adhesion formation with hyaluronic acid after peritoneal surgery in rabbits

OBJECTIVE

To examine the effect of hyaluronic acid, a high-molecular-weight glucosaminoglycan found in the extracellular matrix, on the formation of adhesions, a major source of postoperative complications.

DESIGN

The ability of hyaluronic acid to reduce adhesion formation was evaluated using a standardized rabbit model. The material was administered i.p. at the end of surgery.

SETTING

University laboratory.

ANIMAL(S)

New Zealand White female rabbits.

INTERVENTION(S)

Intraperitoneal administration of various formulations of hyaluronic acid at the end of surgery.

MAIN OUTCOME MEASURE(S)

One week after surgery, a second laparotomy was performed and the extent of adhesion formation was determined.

RESULT(S)

Five separate molecular weight ranges of hyaluronic acid representing eight viscosities between 1,000 and 12,000 centipoise (CPS) were shown to reduce adhesion formation in this model. All volumes, 1 to 30 mL, of hyaluronic acid tested reduced adhesion formation. In addition, the low-viscosity, low-molecular-weight hyaluronic acid significantly reduced adhesion formation when added to the trauma site or when injected at a site remote from the trauma area.

CONCLUSION(S)

This study showed that hyaluronic acid administered at the end of surgery reduced adhesion formation.

Hyaluronic acid modulates acute and chronic inflammation

We have studied the effect of hyaluronic acid (HA) in two standard models of acute and chronic inflammation in the rat, i.e. carrageenin oedema and adjuvant arthritis. Our results show that HA was able to inhibit, in a dose-related fashion, both types of inflammatory reactions. These findings suggest that HA may have a modulatory role in the inflammatory process and may explain, at least in part, the protective role of HA in the inflammatory cartilage damage.

Hyaluronan (hyaluronic acid) and hyaluronectin in the extracellular matrix of human breast carcinomas: comparison between invasive and non-invasive areas

We performed quantitative determination of the distribution of hyaluronan (hyaluronic acid, HA) and the HA-binding protein, hyaluronectin (HN), 2 components of the extracellular matrix of tumor desmoplasia, within 71 human breast carcinomas. Results showed that HA and HN were more elevated in tumoral than in non-tumoral adjacent tissue, and that the peripheral invasive area of tumors contained increased levels of HA and HN as compared with the central non-invasive area (p less than 10(-3) and p less than 10(-5) respectively). HN and HA levels of 61 ductal carcinomas were related to the histological grade of tumors; no significant difference was found between grades for HA; HN was found to be significantly lower in grade III than in grade II tumors (p less than 0.01). HA and HN rates were correlated in grade I and grade II tumors and were not correlated in grade III. Mean percentage of HA saturation level by HN for whole tumors was found to be less than 4%, indicating that HA is essentially free of proteins and could be used as a target for cancer diagnosis or therapy.

Biochemical markers of hepatic fibrosis

Most liver diseases lead to a pathobiochemical reaction termed liver fibrosis. This is a dynamic process implying different rates of progression or regression. Thus, histological examination of a liver biopsy is essential for a diagnosis but biochemical tests are necessary for assessing the activity of the process and monitoring its evolution. We review the most important constituents of liver connective tissue and the biochemical tests developed for evaluating liver fibrosis. The aminopeptide of type III procollagen is the most widely used parameter: two different radioimmunoassays have been developed with different affinities for the two circulating forms of the molecule. The determination of serum P3P reveals an elevation of blood levels both in acute and chronic liver diseases. In the first, serum P3P is an index of hepatic necrosis and inflammation which correlates with other biochemical parameters. In the second it is an index of active fibrogenesis. Moreover, in primary biliary cirrhosis this parameter is an independent prognostic variable and an important predictor of survival. Other immunoassays exist for different collagen cleavage products, but their clinical value is not established. Laminin and fibronectin are the principal structural glycoproteins in liver. Fibronectin determination does not seem to be of clinical value in liver disease. In contrast, serum laminin correlates with the severity of portal venous pressure in advanced liver disease. Its concentration parallels the severity of varices and may indicate the risk of bleeding. Hyaluronate is a high molecular weight polysaccharide, raised serum concentrations reflect both its increased synthesis by activated fibroblasts and its impaired catabolism by the liver. Thus, it may be useful for evaluating and monitoring the progression of chronic liver disease. The measurement of the activity of prolyl 4-hydroxylase as well as that of lysine oxidase and other enzymes has been proposed, but their clinical value is not sufficiently demonstrated. A panel of tests (e.g., laminin, hyaluronate and the aminopeptide of type III procollagen) seems to be recommended for a biochemical assessment of liver fibrosis in clinical practice.

CD44 is the principal cell surface receptor for hyaluronate

CD44 is a broadly distributed cell surface protein thought to mediate cell attachment to extracelular matrix components or specific cell surface ligands. We have created soluble CD44-immunoglobulin fusion proteins and characterized their reactivity with tissue sections and lymph node high endothelial cells in primary culture. The CD44 target on high endothelial cells is sensitive to enzymes that degrade hyaluronate, and binding of soluble CD44 is blocked by low concentrations of hyaluronate or high concentrations of chondroitin 4- and 6-sulfates. A mouse anti-hamster hyaluonate receptor antibody reacts with COS cells expressing hamster CD44 cDNA. In sections of all tissues examined, including lymph nodes and Peyer's patches, predigestion with hyaluronidase eliminated CD44 binding.

Elevated levels of serum hyaluronate and correlation with disease activity in experimental models of arthritis

The serum hyaluronate (HA) concentration was measured in groups of rats immunized for adjuvant or type II collagen arthritis. Serum HA increased as the arthritic lesions developed, correlating with the severity of the disease. This increase in HA was not related to metabolic impairment, because rats with adjuvant arthritis metabolized intravenously administered tritiated HA at a rate similar to that of normal rats. Serum HA levels may be useful as an indicator of synovitis in experimental and possibly in clinical arthritis. Further, this model could serve as an experimental approach for studies of HA metabolism in chronic joint inflammation.

Clinical trial of intra-articular injection of sodium hyaluronate in patients with osteoarthritis of the knee

A multi-centre randomized, double-blind, parallel-group clinical trial was carried out in 63 patients with osteoarthritis of the knee to compare the efficacy and tolerability of a course of intra-articular injections of 20 mg sodium hyaluronate with a similar course of injections of placebo. Treatment consisted of up to 11 injections over a 23-week period. Evaluation was by means of subjective symptom and activity assessments, serially during the course of treatment and also 25 weeks thereafter. Ten patients (5 of 30 on active treatment; 5 of 33 on placebo) were withdrawn prematurely. Pain on movement, assessed by visual analogue scale (VAS) showed statistically significant (p less than 0.05 to p less than 0.0001) reductions in mean scores throughout the first 11 weeks of treatment with sodium hyaluronate but smaller, non-significant, reductions with placebo treatment. The difference between treatments was significant (p less than 0.05) at 5 weeks. Pain at rest, also assessed by VAS, showed little change in mean scores with placebo but with sodium hyaluronate there was a progressive reduction which was significant (p less than 0.01) throughout the period from 5 to 23 weeks. The difference between sodium hyaluronate and placebo was significant (p less than 0.05 to p less than 0.002) at Weeks 5, 11, 15, 19 and 23. 'Activities of daily living' were assessed using a standard scale. There were small improvements with both treatments, significant at some assessments and somewhat greater with sodium hyaluronate than placebo, but there were no statistically significant differences between the groups.(ABSTRACT TRUNCATED AT 250 WORDS)

The influence of high molecular weight sodium hyaluronate (Healon) on the production of migration inhibitory factor

The effect of sodium hyaluronate on the production of migration inhibitory factor (MIF) was studied in a two step MIF-assay. High molecular weight sodium hyaluronate (100 micrograms/ml), added during the inductory step of the MIF-assay, inhibited the production of MIF. The inhibitory effect did not appear to be due to physical factors such as steric hindrance, which may prevent mitogen binding, since cells preactivated with phytohemagglutinin A (PHA) did not produce MIF when incubated in the presence of sodium hyaluronate. The inhibitory effect was still measurable when the sodium hyaluronate was added upto two hours after stimulation of the mononuclear cells with PHA. Inhibition was also found when the cells were preincubated with sodium hyaluronate, and washed prior to mitogen stimulation. Sodium hyaluronate could only be removed from the cells by incubation with hyaluronidase or by incubation of the cells for at least two hours in culture medium, whereafter the cells could be stimulated to the same extent as normal untreated cells to produce MIF. This inhibitory effect on cytokine production may explain the reduced inflammatory reactions found both in vivo and in vitro in the presence of sodium hyaluronate.

Hyaluronate inhibition of cell proliferation

The proliferation of rabbit synovial cells, 3T3 cells, or simian virus-transformed 3T3 cells in cell culture was inhibited by the addition of hyaluronate to the culture medium. This effect was markedly dependent on the molecular weight and concentration of the hyaluronate. At the molecular weight and concentration of hyaluronate present in normal synovial fluid, proliferation was inhibited. At lower molecular weights or concentrations, as found in rheumatoid synovial fluid, hyaluronate was significantly less inhibitory. Thus, the changes in synovial fluid hyaluronate that are associated with arthropathies may contribute to a favorable environment for rheumatoid pannus expansion.

The effect of chronic inflammation on gingival connective tissue proteoglycans and hyaluronic acid

Proteoglycans have been isolated and analysed from extracts of normal and chronically inflamed human gingiva in order to determine the effects of chronic inflammation on these important soft connective tissue extracellular macromolecules. The uronic acid content of glycosaminoglycans isolated by papain digestion of normal and inflamed gingiva did not differ significantly. Likewise, electrophoretic analysis revealed that the content of hyaluronic acid, heparan sulfate, dermatan sulfate and chondroitin sulfate was similar. The sulfated glycosaminoglycans from both sources eluted from a Sepharose C1-6B column with a Kav of 0.45 (approximate Mr 25,000). However, hyaluronic acid from normal gingiva was predominantly of a large size eluting in the void volume of a Sepharose. CL-6B column, while that isolated form inflamed tissue was mostly a small molecular weight species which eluted in the included volume of a Sepharose CL-6B column. Using dissociative conditions, intact proteoglycans could be more readily extracted from inflamed tissues (90% of the total tissue uronic acid) than from normal tissues where only 80% of the total tissue uronic acid was extractable. Even though DEAE-Sephacel ion-exchange chromatography revealed no differences in charge between normal and inflamed gingival proteoglycans, Sepharose CL-4B chromatography revealed more molecular size polydispersity in samples from inflamed tissue than from normal tissue. Taken together, these results indicate that while hyaluronic acid is depolymerized in inflamed tissue, no evidence of sulfated glycosaminoglycan degradation was found. Therefore, the most likely cause for disruption to the molecular integrity of the proteoglycans is via proteolytic alteration to the proteoglycan core protein.

Serum hyaluronate in liver diseases: study by enzymoimmunological assay

It has been suggested that glycosaminoglycans are involved in the pathogenesis of liver fibrosis. Furthermore, recent studies have reported that one of them, hyaluronate, was mainly taken up and degraded by the liver. Using an enzymoimmunological assay, based on hyaluronate-hyaluronectin interaction, serum levels of hyaluronate were measured in 113 patients with various liver diseases. Patients were divided into six groups according to clinical, biological and histological data: Group 1-alcoholic cirrhosis (n = 47) including alcoholic cirrhosis with alcoholic hepatitis (n = 24); Group 2-primary biliary cirrhosis (n = 21); Group 3-cirrhosis related to viral hepatitis (n = 10); Group 4-idiopathic hemochromatosis (n = 17); Group 5-alcoholic fatty liver (n = 8); and Group 6-viral or drug acute hepatitis (n = 10). Ninety-four blood donors were studied as controls. Levels of hyaluronate were found to be strikingly elevated in Group 1 (1,225 +/- 1,137 micrograms per liter), Group 2 (792 +/- 739 micrograms per liter), Group 3 (649 +/- 373 micrograms per liter), and Group 4 (246 +/- 242 micrograms per liter), whereas patients in Group 5 (94 +/- 63 micrograms per liter) and Group 6 (73 +/- 57 micrograms per liter) had values close to controls (23 +/- 17 micrograms per liter). There was a significant correlation between serum hyaluronate and serum albumin, prothrombin time, factor V concentration and serum gamma-globulins. It is suggested that hyaluronate levels reflect both active fibrosis and hepatic failure and may be a quantitative marker of severity of hepatic injury.

Stimulation of mouse B cells by a factor that coisolates with T-cell proteoglycan

We have isolated a factor that copurifies with chondroitin sulfate proteoglycan secreted by mouse splenocytes and some murine T-cell hybridomas. This factor will stimulate proliferation and plaque-forming cell differentiation of B lymphocytes from mouse spleens, even after T cells have been depleted (less than 2% Thy 1.2-bearing cells). Adherent macrophages enhance the activity of this factor, but their function can be replaced in macrophage- and T-cell-depleted populations by small concentrations of a protein mitogen from Salmonella typhimurium. The stimulatory fraction contains chondroitin sulfate, a major protein which has a molecular weight of 74,000 and a minor moiety at 50,000. Stimulatory activity of this material is destroyed by (i) boiling, (ii) mild alkali treatment, and (iii) protease digestion. It is unaffected by RNase and chondroitinase treatments, suggesting that the factor is a protein. Our data define a new B-cell stimulatory substance(s) and suggest that it may be associated with chondroitin sulfate proteoglycan secreted by immune cells.

Immunoenzymoassay of the hyaluronic acid-hyaluronectin interaction: application to the detection of hyaluronic acid in serum of normal subjects and cancer patients

The binding of a hyaluronic acid-binding glycoprotein, hyaluronectin (HN), isolated from human brain, to hyaluronic acid (HA) was investigated with the enzyme-linked immunosorbent assay technique using plastic microtest plates coated with a 50 mg/liter solution of HA in 0.1 M bicarbonate. Optimum conditions for HN binding to HA were in 0.2 M NaCl buffered with 0.1 M sodium phosphate at pH 7. An assay for HA in solution was set up exploiting the fact that HN binding could be inhibited by soluble HA. HA was preincubated for 1 h in a test tube with a 30-ng/ml HN solution (v/v) in the buffer containing 0.1% bovine serum albumin. Incubation on HA-coated microtest plate lasted 4 h and maximum sensitivity was achieved when incubation was carried out at 4 degrees C. HN bound to the plate was revealed by means of alkaline phosphatase-conjugated anti-HN antibodies. The test was used to measure HA inhibitory activity after depolymerization by ferrous ions. No difference was found between inhibitory activity or smaller fragments and that of high-molecular-weight HA. The assay was applied to determination of HA in sera. Specificity was demonstrated by Streptomyces hyaluronidase digestion of reactive material in sera. Other glycosaminoglycans did not interfere with the assay. Recovery of HA was good and intra- and interassay variation coefficients were 6 +/- 2.2 and 12%. In 103 blood donor sera, HA was found at 22.4 +/- 16.7 micrograms/liter. HA was elevated in most of the cancer patient sera tested.

Induction of chondroitin sulfate proteoglycan synthesis and secretion in lymphocytes and monocytes

The ability of mononuclear leukocytes to synthesize and secrete proteoglycans was evaluated. Using radiolabeling with H2 35SO4, it is shown that peripheral blood mononuclear cells (PBMC) and their major subpopulations (B cells, T cells, and monocytes), as well as mouse spleen cells, all secreted easily detectable proteoglycan. After 24-h labeling periods, 90% of macromolecular 35S could be detected in culture media. This material was primarily (greater than 95%) chondroitin-4-sulfate proteoglycan (CSPG). Production and secretion of CSPG could be stimulated more than 200% in PBMC and 300% in T cell populations by high concentrations of concanavalin A and phorbol 12-myristate-13-acetate; lipopolysaccharide induced a small (twofold) but reproducible increase in CSPG secretion by adherent mononuclear leukocytes. The CSPG secreted by PBMC was relatively small in size compared to chondrocyte CSPG (130,000 daltons vs. 2-4 million daltons) but possessed similar sizes of glycosaminoglycan chains and greater solubility in low ionic strength solutions. This sulfated polyanion, which was produced endogenously by leukocytes and was actively secreted, might function as a co-mediator or "second messenger" in certain immune responses.

Glycosaminoglycans: structure and interaction

In the last few years, there has been considerable progress in the studies on glycosaminoglycans, a group of acidic polysaccharides present in the intercellular matrix of connective tissue. X-ray diffraction studies have indicated that these polymers can exist in the condensed phase in some helical form. Chiroptical and hydrodynamic measurements have provided significant information regarding the molecular conformation in solution and other physicochemical properties of the polymers. Studies related to the interaction properties of glycosaminoglycans with polypeptides, metal ions, and other molecules are numerous. This review covers mainly the results and their interpretations of both published and as yet unpublished material of the 1970s, but certain previous data are also included. A present-day concept regarding the structure and interaction properties of these molecules on the basis of various physicochemical measurements is presented. The biosynthesis and metabolism of glycosaminoglycans, and the structure of proteoglycans and glycoproteins, are not discussed.

[Haematological features of anorexia nervosa (author's transl)]

Nine patients with anorexia nervosa were studied, who had varying degrees of bone marrow failure ranging from a slight neutropenia to severe pancytopenia. In addition to routine laboratory work bone marrow biopsies were performed at admission and during the course of disease. In four of those patients erythropoietin excretion per 24 hours was measured by the bioassay in the polycythemic mouse at least twice during the course of treatment. At admission most bone marrow showed a marked although varying hypocellularity with grossly apparant background gelatinous material, which appeared to consist of acid mucopolysaccharides. Leukopenia and the changes of the bone marrow morphology reversed to normal after refeeding. Erythropoietin excretion was only elevated in patients who were anemic and returned to normal when the haematocrit reached normal levels. It seems therefore unlikely that an impaired production of erythropoietin or other postulated humoral factors cause the haemopoietic changes in anorexia nervosa. A direct effect of fat or carbohydrate depletion and/or of the increased mucopolysaccharides upon the proliferation of the haemopoietic cells can be suggested, but is an entirely speculative preposition.

Distribution of glycoconjugates in mouse fibroblasts with varying degrees of tumorigenicity

Analysis of glucosamine labeled glycoconjugates in cultured cells has been made comparing 2 clones and the parent embryonic mouse cell line. Hyaluronic acid, heparan sulphate, and chondrotin sulphate as well as a complex mixture of glycopeptides were found in the medium, the trypsinate, and the trypsinized cells, although the distribution was not uniform. The 3 cell lines had very similar in vitro growth properties, including their plating efficiency in viscous medium. However, the tumorigenicity of the cells, determined syngeneic mice, was found to differ. All 3 cell lines were found to have similar glycoconjugate distributions, although a slight relative increase in labeled hyaluronic acid was found in the more tumorigenic mass cell line than either of the clones. The possible significance of this increase is discussed.

Experimental fibroplasia in the rabbit vitreous. Effects of hyaluronidase and implantation of autologous dermal tissue

Intravitreal implantation of dermal connective tissue in rabbits caused a fibroplasia resulting in vitreous retraction, retinal detachment, and traction of nervous tissue from the optic nerve into the vitreous space. Following implantation into eyes with an intact vitreous the incidence of retinal detachment was low (2 eyes of 12). When the hyaluronic acid of the vitreous was degraded by hyaluronidase prior to implantation, 9 eyes of 12 developed a progressive detachment of the retina, usually within one or two months. Intravitreal fibroplasia was found to be an important pathogenic factor causing deteachment of the retina.

Epidemic polyarthritis: a cytological, virological and immunochemical study

A patient with epidemic polyarthritis was studied within 48 hours of onset when specific serum antibodies were still low. The synovial fluid showed a fall in hyaluronic acid level and rise in protein levels though the immune globulins, and especially IgM, rose to a lesser degree and remained well below the levels in the serum. Attempts to grow virus from synovial fluid or blood lymphocytes failed despite the use of several new techniques. The complement components C'3 and C'4 were not depleted in serum or synovial fluid. The synovial fluid was devoid of neutrophil leucocytes, and contained predominantly monocytes and macrophages which were remarkable for mitotic and for enhanced and indiscriminate phagocytic activity. From this and other evidence, an explanation is proposed for the cytological response and difficulties in recovering infective virions in virus-induced arthritis. No virus antigen was detected in the supernatant synovial fluid and electron microscopy showed virus-like particles only in cytolysosomes.

Hyaluronic acid: a novel, double helical molecule

Films prepared from a deformable gel (or putty) of hyaluronic acid show high crystallinity and orientation in their x-ray diffraction patterns. We have derived a probable structure for the molecules in these films. This is a double helix in which two identical, left-handed strands are antiparallel to one another. Each strand has four disaccharide residues per pitch length. Although the putty is prepared at pH 2.5, at which dilute solutions of hyaluronic have exaggerated rheological properties, the double helical form can also exist at physiological pH and therefore may be a biologically important form.