Permeability of hyaluronic acid solutions

The permeability of hyaluronic acid solutions was measured in a chamber closed at each end by semipermeable 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.     

Cigarette smoke degrades hyaluronic acid

Cigarette smoke has been implicated in the pathogenesis of a variety of diseases that affect connective tissues. The effect of the gas phase of cigarette smoke on hyaluronic acid was investigated in vitro. The smoke markedly reduced the chain length of purified hyaluronic acid as assessed by both viscometry and gel chromatography. The hyaluronate exposed to smoke, nevertheless, could aggregate proteoglycans, although the viscosity of the aggregates was lower than in those formed with the unexposed material. The degradation of the hyaluronate was a rapid phenomenon and was inhibited by dimethylsulfoxide, a known scavenger of hydroxyl radicals. We conclude that free radicals in the gas phase of cigarette smoke degrade hyaluronic acid in vitro.     

Cigarette smoke degrades hyaluronic acid

Cigarette smoke has been implicated in the pathogenesis of a variety of diseases that affect connective tissues. The effect of the gas phase of cigarette smoke on hyaluronic acid was investigated in vitro. The smoke markedly reduced the chain length of purified hyaluronic acid as assessed by both viscometry and gel chromatography. The hyaluronate exposed to smoke, nevertheless, could aggregate proteoglycans, although the viscosity of the aggregates was lower than in those formed with the unexposed material. The degradation of the hyaluronate was a rapid phenomenon and was inhibited by dimethylsulfoxide, a known scavenger of hydroxyl radicals. We conclude that free radicals in the gas phase of cigarette smoke degrade hyaluronic acid in vitro.     

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.     

Therapeutic effect of hyaluronic acid injection for knee and shoulder joint

It is known that hyaluronic acid can protect against damage to articular cartilage and helps to lessen friction between joint surfaces. Furthermore, it is reported that hyaluronic acid is effective for pain relief and for the risk of adhesion, and contractures of joints. The injection of hyaluronic acid is useful for the treatment of frozen shoulder, osteoarthritis, and rheumatoid arthritis. The risk of infection is a rare, though important, possibility, however this method is relatively safe.     

Effect of oxygen-derived free radicals on hyaluronic acid

To investigate possible mechanisms of hyaluronic acid depolymerization, superoxide anion and other secondary oxygen-derived free radicals were generated in vitro and allowed to act upon a hyaluronate substrate. Superoxide, generated either enzymatically with xanthine oxidase or by stimulation of polymorphonuclear leukocytes, reduced the viscosity of hyaluronate solutions dramatically while the chromatographic profiles of the glycosaminoglycan shifted toward lower molecular weights. Superoxide-treated hyaluronate also became susceptible to further degradation by beta-N-acetylglucosaminidase A. Experiments with scavengers of various toxic oxygen-derived free radicals clearly implicated these reactants as mediators of hyaluronate depolymerization. Generation of superoxide by leukocytes in vivo may account for the loss of synovial fluid viscosity that accompanies inflammatory joint disease.     

Modulation of mitogen-dependent lymphocyte stimulation by hyaluronic acid

The stimulation of incorporation of [3H]-thymidine into mononuclear cells (MC) from human body by plant lectins was assessed in the presence of varying concentrations of hyaluronic acid (HA). The simultaneous addition of HA and phytohemagglutinin to MC cultures resulted in a decrease in the incorporation of radioactivity. The magnitude of the decrease was directly related to the concentration of HA added. Kinetic studies, however, indicated that the addition of HA after the initiation of DNA synthesis in the MC cultures also resulted in a decline of the rate of incorporation of radioactivity. The kinetic and analytical data suggest that DNA synthesis by MC in inflammatory arthropathies might be modulated by the HA rich microenvironment of the joint and that this modulation could also occur even if the MC were stimulated before they reached the joint tissues.     

Effects of hyaluronic acid on cartilage degradation.

Based on the published literature available so far, it appears that naturally derived hyaluronic acid (HA) and newer formulations available on the market belong to the pharmacologic class of slow-acting drugs for the treatment of osteoarthritis. These compounds seem to have the potential to modulate the painful symptoms of osteoarthritis as well as to improve the function of the osteoarthritis joint. Positive clinical consequences are based on direct and indirect effects of viscosupplementation associated with a normalization of the rheologic properties of the osteoarthritic synovial fluid, decreased inflammation, and end-coating of the pain receptors in the osteoarthritis joint. Few in vivo data exist in humans to support the concept that HA formulations could have a structure-modifying effect on human osteoarthritis cartilage. Animal-based studies have demonstrated positive effects of exogenous HA on pain in the joint, heat shock proteins, and in models of osteoarthritis. Although many promising effects of exogenous HA have been reported, there remains uncertainty as to the effectiveness of reversing cartilage injury and other manifestations of joint diseases with exogenous HA because of difficulties in interpreting and unifying results of these studies. This is due largely to differences of cartilage source in models of joint/cartilage injury, multiple end points, the controls employed, analytical techniques, and the molecular weight of exogenous HA used. There exists a need for uniform agreement as to the choice of injury model, time points of the study, evaluation tools, and source and molecular weight of the HA used if we are to determine whether exogenous application of HA has a truly beneficial role in the reversal of cartilage injury.     

The pain associated with intraarticular hyaluronic acid injections for trapeziometacarpal osteoarthritis

Trapeziometacarpal osteoarthritis predominantly affects middle-aged women. Most cases with rhizarthrosis can be managed successfully by conservative means. The purpose of this prospective study was to evaluate pain and tolerability of viscosupplementation therapy with hyaluronic acid (HA) for trapeziometacarpal osteoarthritis. Groups A and B consisted of eight patients each with Eaton stage 3 or 4 rhizarthrosis, who underwent one cycle of three injections of (one per week) 0.3 cm³ sodium hyaluronate. The injections for group A were under fluoroscopy control, but fluoroscopy was not used in group B. Pain and tolerability of both groups A and B were measured and compared. The patients of the groups were also asked to evaluate the tolerability of the treatment. The results suggested that HA injection in the carpometacarpal joint is a tolerable procedure but the patients complained of pain and discomfort during the injections. The pain in group A was much greater than in group B. Viscosupplementation for the treatment of trapeziometacarpal osteoarthritis is a viable treatment option for stages 3 and 4 patients when they do not want to be operated on. It is a tolerable but not a painless procedure especially when it is done without fluoroscopy control. We recommend giving injections under fluoroscopy control.     

HA-HAase联检对膀胱移行细胞癌的诊断价值

目的 探讨透明质酸(HA)和透明质酸酶(HAase)对膀胱移行细胞癌的诊断意义。方法 41份尿液标本取自移行细胞癌患者,另30份尿液取自对照组(包括正常人、泌尿生殖系其他疾病患者)。采用放射免疫标记技术检测尿液HA和HAase水平。结果 患者尿中HA水平是对照组的2-6倍(P<0.001),而尿中HAase水平在G2/G3移行细胞癌患者中显著升高,是对照组的3-7倍(P<0.001)。HA-HAase联检在膀胱癌诊断中具有较高的灵敏度(90.2%)、特异度(86.6%)和精确度(88.7%)。结论 HA-HAase联检是诊断膀胱癌的一种非侵入性、高灵敏度、高特异度的检测方法。     

Novel hyaluronic acid coating for potential use in glucose sensor design

Biocompatibility issues such as protein deposition and fibrous capsule formation significantly reduce the sensitivity of implanted glucose sensors. One of the approaches to improve the sensor biocompatibility is to disguise the sensors with coatings that mimic body conditions. We anticipate that a biomimetic coating based on hyaluronic acid (HA) would minimize the problems related to protein deposition and fibrous tissue formation. Diffusion experiments were conducted to assess the transport properties of HA coating on a polyvinyl alcohol (PVA) membrane using a classic diffusion cell. HA was coated on PVA membranes, as cross-linked HA membranes alone have poor mechanical strength. The effective diffusivities of glucose and oxygen in a HA/PVA membrane (95% confidence interval) are 1 +/- 0.26 x 10(-4) and 1.42 +/- 0.34 x 10(-4) cm(2)/min, respectively. The effective diffusivities of glucose and oxygen in HA/PVA membranes were approximately two-thirds when compared with the diffusivities of glucose and oxygen (7.29 x 10(-5) and 2.34 x 10(-4) cm(2)/min, respectively) in pure PVA membranes. The results indicate that the HA/PVA membranes have transport properties similar to the commonly used pure PVA membranes, and thus may find usefulness as a coating for implantable glucose sensors.     

Injection technique of intra-articular hyaluronic acid for knee osteoarthritis and periarthritis of shoulder

Osteoarthritis of the knee and periarthritis of shoulder are very common. Although conservative treatments have been advocated for periarthritis of shoulder and the early stages of osteoarthritis, few reliable options are available, consisting of lifestyle modification, physical therapy, nonsteroidal antiinflammatory medications and intraarticular steroid injections. These measures, however, are not always effective. Viscosupplementation is one of reliable options for treatments of symptomatic knee osteoarthritis and periarthritis of shoulder. This paper described how to perform intra-articular hyaluronic acid injections accurately, safely, and easily in the knee and shoulder joints.     

Inhaled hyaluronic acid against exercise-induced bronchoconstriction in asthma

Hyaluronic acid (HA) is a polysaccharide that is present in human tissues and body fluids. HA has various functions, including a barrier effect, water homeostasis, stabilizing the extracellular matrix, increased mucociliary clearance and elastin injury prevention. It may therefore exert prophylactic activity in the treatment of asthma. We tested the hypothesis that HA inhalation will prevent exercise-induced bronchoconstriction (EIB) in a randomised double-blinded placebo-controlled crossover study. Sixteen asthmatic patients with EIB were included in the study (mean (SD)) (age 24.5 (7.3) yr, FEV1 88.6 (11.3) %predicted, PC20 methacholine (g-mean (SD in DD)) 0.4 (1.5) mg/ml). On two separate visits an exercise challenge was performed 15 min post-inhalation of either HA (3 ml 0.1% in PBS) or placebo (3 ml PBS). The maximum fall in FEV1 and the AUC 30 min post-exercise were used as outcomes. After inhalation of both HA and placebo, baseline FEV1 decreased significantly (HA 4.1 (3.1)%, placebo 2.9 (4.1)%, P<0.017). The maximum fall in FEV1 following exercise challenge was not significantly different between HA versus placebo (median HA 22.50%, placebo 27.20%, P=0.379), as was the AUC (median HA 379.3 min*%fall, placebo 498.9 min*%fall, P=0.501). We conclude that at the current dose, inhaled HA does not significantly protect against EIB. This suggests that HA is not effective as a prophylaxis for EIB in patients with asthma.