Cross-linked Hyaluronic Acid Gel Research Articles

Using cross-linked hyaluronic acid gel to prevent postoperative lumbar epidural space adhesion: in vitro and in vivo studies.

Hyaluronic acid prevents tissue adhesion after different surgeries. Physical barriers and inflammatory regulation have been suggested to be involved in the mechanism of these clinical effects. However, the molecular mechanism by which hyaluronic acid prevents epidural adhesion has not yet been reported. In the current in vivo studies, we investigated cross-linked hyaluronic acid gel in the regulation of scar gene expression, the accumulation of fibroblasts in scar tissue, and the prevention of epidural adhesion. The effect of cross-linked hyaluronic acid gel on the secretion of inflammatory factors was observed in vitro. In addition, to ensure the accuracy and reliability of the in vivo gene expression results, we used a cell model to detect the target genes in vitro. The expression levels of TGFβ1 and COL1A1 mRNA were decreased in the cross-linked hyaluronic acid gel-treated group, and the protein expression of levels TGFβ1 and COL1A1 were also reduced, as detected by Western blotting in vitro and in vivo (P < 0.05). Histomorphometry results demonstrated that the number of fibroblasts in the experimental group was significantly lower than that in the control group 2weeks postoperatively. Micro-CT scans showed that the cross-linked hyaluronic acid gel could reduce adhesion in the epidural space after laminectomy. Additionally, the cross-linked hyaluronic acid gel could inhibit IL-6 secretion. These results indicate that cross-linked hyaluronic acid gel can prevent epidural adhesion by inhibiting inflammatory factors, such as IL-6, and downregulating TGFβ1 and COL1A1 mRNA expression. These slides can be retrieved under Electronic Supplementary Material.

Gait analysis following single-shot hyaluronic acid supplementation: a pilot randomized double-blinded controlled trial

ObjectivesViscosupplementation with new-generation, polyol-containing, cross-linked hyaluronic acid (HA) gels reduces joint inflammation in patients with knee osteoarthritis. Gait analysis is a complementary outcome measure to standard patient-reported scores and physical measures for testing the effect of HA injection. This three-arm, prospective, randomized, controlled, double-blind, feasibility pilot study investigated which gait parameters are more sensitive following a single bolus injection of polyol-containing HA for knee osteoarthritis.MethodsTwenty-two patients with Ahlbäck grade II–III knee osteoarthritis were randomly allocated into three groups: (1) HA + mannitol (n = 9), (2) HA + sorbitol (n = 5), and (3) saline placebo (n = 8). Patients were assessed by blinded observers prior to injection and at 4 weeks post-injection (4W). Outcome measures included the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Knee Society score (KSS), EuroQol in five-dimensions (EQ-5D), VAS pain, and VAS stiffness. Gait was assessed over 30 m using a portable inertial-based data logger (Physilog®).ResultsDifferences between 4W and baseline were statistically significant for the mannitol-containing viscosupplement, with a median increase of 0.076 m/s on gait speed (p = 0.039), 0.055 m on stride length (p = 0.027), and 15 points on the KSS (p = 0.047). In contrast, the HA + sorbitol and saline groups demonstrated no significant changes from baseline to 4W in any gait parameters or self-reported outcome measures (all p > 0.3). The observed increase in gait speed is approximately 13% greater than the mean difference between healthy subjects and those with knee osteoarthritis, is clinically important, and thus is a sensitive gait parameter.ConclusionsThis study demonstrated gait speed and stride length are the most relevant gait parameters to investigate when assessing the effect of polyol-containing HA viscosupplementation. This study supports the need for a larger, randomized, controlled, clinical trial to assess the effect of a single-bolus HA injection versus multiple injections in people with knee osteoarthritis using both gait performance and self-reported parameters of knee function.Trial registrationThis study was retrospectively registered at clinicaltrials.gov on August 20, 2018, and assigned #NCT03636971.Level of evidenceI

Improving the Rheological Properties of Cross-linked Hyaluronic Acid Gels by Mixing in Mannitol as a Radical Scavenger

Purpose: This study aimed to evaluate the effect of mixing mannitol into crosslinked hyaluronic acid gels on their rheological properties. Methods: Cross-linked hyaluronic acid gels were prepared by mixing in mannitol to our own manufacturing process, and then the changes in their rheological properties due to chemical and thermal oxidative stress were investigated. The rheological factors evaluated were the storage modulus (G'), loss modulus (G), complex viscosity (G*) and phase angle (P/A). Results: Mixing mannitol into the cross-linked hyaluronic acid gels caused their elasticity (G') and viscosity (G) to resist both frequency increase and oxidative stress caused by chemical and thermal stress. Adding mannitol also resulted in improved urine secretion in an animal model, and we therefore expect that it will reduce edema due to osmotic pressure. Conclusion: Mannitol’s antioxidant effect contributed to the improving the cross-linked hyaluronic acid gels’ rheological properties.

Cross-linked hyaluronic acid gel occlusive device for the treatment of dry eye syndrome.

PurposeA new cross-linked hyaluronic acid (xlHA) gel occlusive device was assessed for safety and efficacy in the treatment of dry eyes.MethodsThis was an institutional review board-approved, single-site, open-label, prospective study to assess the efficacy and safety of placing the xlHA gel in the lower canaliculus. Seventy-four participants aged 25–95 years with dry eyes, who failed treatment with artificial tears, were included. Patients were assessed with corneal slit lamp examination with fluorescein staining and with Schirmer’s test, breakup time (TBUT), and tear meniscus height (TMH) at baseline, 1 month, and 3 months. Patients were followed at 6 months with a telephone questionnaire. The procedure entailed inserting ~0.2 mL of xlHA gel into each lower lid canaliculus with a syringe and lacrimal irrigator. Patients were followed for adverse events.ResultsSixty-three patients completed the study (48 females, 15 males), with an average age of 67 years. Slit lamp demonstrated improved corneal fluorescein staining. Schirmer’s tests demonstrated an average increase over baseline of 3.67 mm after 3 months. TBUT improved 87% and TMH increased by 57% at 3 months over baseline. All objective measures were statically significant. There was one case of conjunctivitis that resolved and was felt to be an incidental viral infection.ConclusionThe xlHA Occlusive Device offers a new, safe, and effective method to treat dry eyes. It appears to have efficacy for at least 3 months on clinical examination. The xlHA gel demonstrated a good tolerance and safety profile.

Skin bacterial flora as a potential risk factor predisposing to late bacterial infection after cross-linked hyaluronic acid gel augmentation.

IntroductionCross-linked hyaluronic acid (HA) gel is widely used in esthetic medicine. Late bacterial infection (LBI) is a rare, but severe complication after HA augmentation. The aim of this study was to determine whether patients who underwent the HA injection procedure and developed LBI had qualitatively different bacterial flora on the skin compared to patients who underwent the procedure without any complications.MethodsThe study group comprised 10 previously healthy women with recently diagnosed, untreated LBI after HA augmentation. The control group comprised 17 healthy women who had a similar amount of HA injected with no complications. To assess the difference between the two groups, their skin flora was cultured from nasal swabs, both before and after antibiotic treatment in the study group.ResultsA significant increase in the incidence of Staphylococcus epidermidis was detected in the control group (P=0.000) compared to the study group. The study group showed a significantly higher incidence of Staphylococcus aureus (P=0.005), Klebsiella pneumoniae (P=0.006), Klebsiella oxytoca (P=0.048), and Staphylococcus haemolyticus (P=0.048) compared to the control group.ConclusionThe bacterial flora on the skin differed in patients with LBI from the control group. The control group’s bacterial skin flora was dominated by S. epidermidis. Patients with LBI had a bacterial skin flora dominated by potentially pathogenic bacteria.

Cross-linked hyaluronic acid gel inhibits metastasis and growth of gastric and hepatic cancer cells: in vitro and in vivo studies.

Cross-linked hyaluronic acid gel (CHAG) has been used to prevent postoperative adhesion of abdominal tumorectomy. However, its effect on tumor cells is still unknown. This paper was designed to investigate the effect of CHAG on metastasis and growth of tumor cells. Migration and invasion assays, Western blotting, pull down assay, siRNA interference, and nude mice implantation tumor model were applied in this study. The results of in vitro experiments with gastric cancer cell line AGS and hepatic cancer cell line HepG2 showed that CHAG inhibited the migration and invasion activities, the MAPK and PI3K/Akt mediated signaling, the activation of small G proteins Rac1 and RhoA, and the expression of MMPs and PCNA initiated by EGF, through blocking the activation of EGFR. CHAG also had inhibitory effect on activation of other membrane receptors, including integrin and VEGFR. When the expression of hyaluronic acid receptors (CD44 or RHAMM) was interfered, the above inhibitory effects of CHAG still existed. In vivo experimental results showed that CHAG suppressed colonization, growth and metastasis of gastric cancer cell line SGC-7901 in peritoneal cavity of nude mice. In conclusion, CHAG had inhibitory effect on tumor cells, through covering cell surface and blocking the interaction between extracellular stimulative factors and their receptors.

Prevention of anterior glottis web with hyaluronic acid derivatives in rabbit model.

Validating an antiadhesive strategy to prevent anterior glottic web (AGW) development. Prospective animal study in rabbits. Fifteen New Zealand white rabbits were randomly divided into three equal groups (five rabbits each), applying either HyFence (HF: 0.1 g/vocal fold), an antiadhesive test agent; mitomycin-C (MMC: 1 mg/ml, 4 min) as reference therapy; or saline (control group) to AGWs induced by laryngofissure technique (previously reported by us). At week 8, the extent of AGW was measured to assess preventive effects of HF and MMC, and laryngeal specimens were sampled for high-speed recording and histologic analysis. AGW induction was successful in all five (100%) control rabbits, each demonstrating fibroconnective tissue and collagen fibers at anterior commissure, with AGW ratio averaging 0.57 ± 0.052. An AGW was seen in 100% of the rabbits survived in the MMC group (n = 2) with the 60% (n = 3) of the MMC rabbits expired due to postprocedure infections. The average AGW ratio was 0.28 ± 0.070 in the MMC group. AGW formation rate was 50% in HF group with one rabbit expired from infection. Mean AGW ratio was lowest in the HF group (0.23 ± 0.10; P = 0.013). Microscopically, AGW induction sites in HF-treated rabbits displayed significantly fewer collagen fibers (P = 0.009) by comparison. This is the first reported use of a cross-linked hyaluronic acid gel that may prevent AGW formation. N/A. Laryngoscope, 126:2320-2324, 2016.

Perivascular sustained release of atorvastatin from a hydrogel-microparticle delivery system decreases intimal hyperplasia

Intimal hyperplasia (IH) is the major cause of grafted vessel occlusion and occurs frequently after bypass intervention. No pharmaceutical formulation is currently available to prevent this pathology. Local perivascular delivery of an appropriate active compound released in a time-dependent manner (from day one up to 4weeks) is necessary for an efficient single-administration preventive therapy. To this aim, we propose the combination of gel and microparticles delivery system containing atorvastatin (ATV). The incorporation of ATV in a cross-linked hyaluronic acid gel, provided in vitro a fast release over 3days, while ATV-loaded poly-lactic-co-glycolic acid (PLGA) microparticles dispersed in the gel gave a sustained release over 4weeks. In vivo, ATV formulations were applied perivascularly in mice undergoing carotid artery ligation. IH was significantly reduced (‐68%) in presence of ATV incorporated in hyaluronic acid gel and encapsulated in microparticles compared to control. No significant IH alteration was observed when ATV was incorporated only in the gel (fast release) or only in the microparticles (slow release) demonstrating that a biphasic release of ATV is essential to interfere with the development of IH.ATV was detected in adjacent tissues 28days after the intervention, showing the sustained presence of the drug in vivo. After four weeks ATV was not detected in remote tissues, except at a very low concentration (0.044ng/mg) in the liver, suggesting a very low risk of systemic toxicity of locally delivered ATV. Additionally, the ex vivo data showed that ATV in solution permeates through isolated human saphenous veins and thus is a good candidate for perivascular delivery.Our data demonstrate that a local biphasic ATV release on the mice ligated carotid efficiently prevents the development of IH without apparent toxicity.

Multivalent hyaluronic acid bioconjugates improve sFlt-1 activity in vitro

Anti-VEGF drugs that are used in conjunction with laser ablation to treat patients with diabetic retinopathy suffer from short half-lives in the vitreous of the eye resulting in the need for frequent intravitreal injections. To improve the intravitreal half-life of anti-VEGF drugs, such as the VEGF decoy receptor sFlt-1, we developed multivalent bioconjugates of sFlt-1 grafted to linear hyaluronic acid (HyA) chains termed mvsFlt. Using size exclusion chromatography with multiangle light scattering (SEC-MALS), SDS-PAGE, and dynamic light scattering (DLS), we characterized the mvsFlt with a focus on the molecular weight contribution of protein and HyA components to the overall bioconjugate size. We found that mvsFlt activity was independent of HyA conjugation using a sandwich ELISA and in vitro angiogenesis assays including cell survival, migration and tube formation. Using an in vitro model of the vitreous with crosslinked HyA gels, we demonstrated that larger mvsFlt bioconjugates showed slowed release and mobility in these hydrogels compared to low molecular weight mvsFlt and unconjugated sFlt-1. Finally, we used an enzyme specific to sFlt-1 to show that conjugation to HyA shields sFlt-1 from protein degradation. Taken together, our findings suggest that mvsFlt bioconjugates retain VEGF binding affinity, shield sFlt-1 from enzymatic degradation, and their movement in hydrogel networks (in vitro model of the vitreous) is controlled by both bioconjugate size and hydrogel network mesh size. These results suggest that a strategy of multivalent conjugation could substantially improve drug residence time in the eye and potentially improve therapeutics for the treatment of diabetic retinopathy.

Biocompatibility and Antifibrotic Effect of UV-Cross-Linked Hyaluronate as a Release-System for Tranilast after Trabeculectomy in a Rabbit Model—a Pilot Study

Purpose: To analyze the release kinetics and the clinical and histological effects of UV-cross-linked hyaluronic acid as a release-system for the transforming growth factor β-2 antagonist tranilast with anti-phlogistic properties on intraocular pressure after trabeculectomy in an aggressive scarring animal model.Methods: Hyaluronate acid was UV-cross linked and loaded with tranilast. The release of tranilast into a buffered salt solution was assessed spectrophotometrically. Glaucoma filtration surgery, similar to that performed in clinical practice, was performed on chinchilla rabbits. The rabbits were divided in 3 groups. (Group A: trabeculectomy alone, group B: trabeculectomy with a cross-linked hyaluronic acid gel preparation and group C: trabeculectomy with cross-linked hyaluronic gel preparation mixed with tranilast). Antifibrotic efficacy was established by clinical response and histologic examination.Results: The cross-linked gels released tranilast for up to 26 h. The release plotted as a function of the square root of time was consistent with a largely diffusion-controlled release system. Both the gel preparation alone and the gel preparation mixed with tranilast were well tolerated in vivo. No adverse effects such as inflammation, corneal toxicity or blurring of the optical media were observed. The intraocular pressure reached preoperative levels within 9 days after surgery in control animals and group B, but remained significantly reduced (p = 0.00016) in the group with tranilast until day 22.Conclusions: The data of this pilot study suggest that the intraoperative application of UV-crossed linked hyaluronic acid used as a slow release system for tranilast may improve the surgical outcome of glaucoma filtration surgery.

Surgical correction of HIV-associated facial lipoatrophy

Surgical correction of HIV-associated facial lipoatrophy

Viscoelastic properties of phonosurgical biomaterials at phonatory frequencies

The purpose of this study was to examine the functional biomechanical properties of several injectable biomaterials currently or potentially used for vocal fold augmentation. Rheometric investigation of phonosurgical materials in vitro. Linear viscoelastic shear properties of 3% bovine collagen (atelocollagen), micronized AlloDerm (Cymetra; LifeCell Corp., Branchburg, NJ), calcium hydroxylapatite (CaHA) (Radiesse; BioForm Medical, San Mateo, CA), and 2.4% cross-linked hyaluronic acid (HA) gel (Juvéderm; Allergan, Inc., Irvine, CA) were quantified as functions of frequency covering the phonatory range, and compared to those of the human vocal fold cover. Measurements of elastic shear modulus (G') and dynamic viscosity (eta') were made at up to 250 Hz with a controlled-strain simple-shear rheometer. Linear least-squares regression was conducted to curve-fit log G' and log eta' versus log frequency, and statistical analysis was performed with one-way analysis of variance. Radiesse and Cymetra were found to be the stiffest and the most viscous materials, followed by Juvéderm and atelocollagen. There were significant differences in the magnitudes of G' and eta' among the phonosurgical materials and the normal human vocal fold cover (p < .001), whereas there was no significant difference in the frequency dependence of G' and eta' among the materials. Post hoc Tukey tests revealed significant differences (p < .05) in pairwise comparisons of the magnitudes of G' and eta' among all materials and the vocal fold cover. These findings suggested that although these biomaterials may be injected lateral to the lamina propria for the treatment of glottic insufficiency, none of them are rheologically optimal for the functional reconstruction of the vocal fold lamina propria.

A double-blind, clinical evaluation of facial augmentation treatments: a comparison of PRI 1, PRI 2, Zyplast ® and Perlane ®

Facial wrinkles are caused by weakening of the sub-dermal collagen support layer. Dermal fillers can be used to treat wrinkles, and this double-blind, randomised, single-centre study compared four fillers: PRI 1, PRI 2 (both porcine collagen), Zyplast (purified bovine collagen) and Perlane (cross-linked hyaluronic acid gel). 79 females (aged 25-55 years) with wrinkles in the upper lip line border were randomised to PRI 1 (19 patients), PRI 2 (19 patients), Perlane (23 patients), Zyplast (18 patients). Patients were assessed at 1 week and 1, 3, 6, 9 and 12 months using 2D images and by mathematically derived facial volume changes using 3D stereophotogrammetry. All treatments produced larger, less wrinkled, more prominent lips. PRI 1, PRI 2 and Zyplast showed similar lip volume gains, with Perlane showing the greatest upper lip volume increase. All treatments were comparable for rates of decrease in upper lip volume post-treatment, however, Perlane maintained higher lip volume gains at each time point. Investigators indicated PRI 1 was significantly easier to deliver than Zyplast. Patient satisfaction scores were similar, though there was a trend towards greater dissatisfaction for PRI 1 and PRI 2 at month 9 (p=0.052). Treatment was well-tolerated, with 'cold sore' being the most common adverse event. Results showed that PRI 1 and PRI 2 were comparable to Perlane and Zyplast as dermal fillers. Further rigorous studies are required to establish the performance of dermal fillers and patient acceptability. We propose the utilisation of stereophotogrammetry for assessment of volume changes.

A new antibacterial carrier of hyaluronic acid gel

BackgroundPostoperative infection following total joint arthroplasty is thought to be one of the most serious and devastating complications. To develop an effective treatment for this complication, we tested a bioabsorbable antibacterial carrier that is made from novel cross-linked hyaluronic acid (HA) gel and gentamicin (GM). MethodsAntibacterial activity of the carrier was evaluated by the agar diffusion test, direct contact test, in vivo mouse model, and in vivo rabbit osteomyelitis model. ResultsGM-containing HA gel suppressed bacterial growth both in vitro and in vivo. In the rabbit osteomyelitis model, beads coated with HA gel containing GM did not disturb bone ongrowth in the femoral stem. ConclusionsOur bioabsorbable carrier of antibioticcontaining HA gel is effective for prophylactic treatment or treatment of an actual deep infection following total joint arthroplasty.

Randomized, Double‐Blind Comparison of the Efficacy of Two Hyaluronic Acid Derivatives, Restylane Perlane and Hylaform, in the Treatment of Nasolabial Folds

Cross-linked hyaluronic acid gels may offer longer-lasting cosmetic correction and a lower risk of immunogenicity than other soft tissue augmentation agents. To compare the efficacy and safety of a non-animal-stabilized hyaluronic acid gel (Restylane Perlane, Q-Med, Uppsala, Sweden) with that of a hylan B gel (Hylaform, Genzyme Corp., Cambridge, MA, USA), a cross-linked hyaluronic acid from chicken combs, for treatment of nasolabial folds. One hundred fifty patients with moderate or severe nasolabial folds were randomized to contralateral treatment with Restylane Perlane and Hylaform. Efficacy was assessed using semi-objective outcome instruments at 3, 4.5, and 6 months after achievement of an "optimal cosmetic result". Patients subsequently underwent open-label bilateral retreatment with Restylane Perlane (if required) and were followed up for a further 6 months. The two products were equally effective in producing an optimal cosmetic result, although fewer treatment sessions were required with Restylane Perlane. At 6 months post-treatment, a higher proportion of patients showed a > or = 1-grade improvement in Wrinkle Severity Rating Scale (WSRS) score with Restylane Perlane (75%) than with Hylaform (38%). Restylane Perlane was considered superior in 64% of patients, whereas Hylaform was superior in 8% of patients. Treatment-related adverse events tended to be more frequent with Restylane Perlane. Local injection-site reactions were generally transient and mild or moderate in intensity and were no more frequent after Restylane Perlane retreatment. Restylane Perlane provides a more durable esthetic improvement than Hylaform and offers acceptable tolerability.

Photo-responsive degradation of heterogeneous hydrogels comprising crosslinked hyaluronic acid and lipid microspheres for temporal drug delivery

A new concept for inflammation responsive drug delivery systems using biodegradable hydrogels of crosslinked hyaluronic acid (HA) has been proposed in our recent studies [ l-3 1. HA is well known to be degraded specifically b;r the presence of hydroxyl radicals, which are produced by phagocytic cells such as leukocytes and macrophages, locally at inflammatory sites [ 41. Our system was established by constructing a heterogeneous-structured device of drug microreservoirs (lipid microspheres) dispersed into degradable matrices of crosslinked HA gels. The most attractive characteristics of this device are: (1) to release lipid microspheres (LM) in response to surface-controlled degradation of crosslinked HA gels and (2) to be quantitatively inflammation-responsive and degradable. These unique features of the device are favorable to regulate drug delivery in several inflammatoryrelated diseases, where LM are released in response to inflammation-induced degradation. The heterogeneous structured device of our design has much potential in drug delivery for severe inflammation. It is well recognized that dysfunction induced by free radicals may be a

Regulated release of drug microspheres from inflammation responsive degradable matrices of crosslinked hyaluronic acid

Heterogeneous structured devices consisting of lipid microspheres (LM) in degradable matrices of hyaluronic acid (HA) crosslinked with polyglycerol polyglycidylether were prepared and their inflammation responsive degradation was investigated in vivo. Hydroxyl radicals produced by the reaction of H 2O 2 and FeSO 4 induced a rapid but limited degradation of the crosslinked HA gels. Zero ordered release of LM was achieved in proportion to the degradation of crosslinked HA gels according to surface-controlled mechanism. In vivo implantation experiments revealed the quantitative degradation of the HA gel in response to inflammation. Therefore, crosslinked HA gels may be promising devices as inflammation (stimulus)-responsive degradable matrices for implantable drug delivery.

Inflammation responsive degradation of crosslinked hyaluronic acid gels

A biodegradable hydrogel of hyaluronic acid (HA) crosslinked with glycidylether was prepared and its degradation by hydroxyl radicals in vitro and by inflammation in vivo was investigated. In vitro, hydroxyl radicals produced by the reaction of H 2O 2 and FeSO 4 induced a rapid but limited degradation of the crosslinked HA gels. The degradation profiles could be fit to a theoretical equation assuming that HA gels degrade preferentially from the gel surface. The in vitro degradation of crosslinked HA gels by hyaluronidase was negligible due to the prevention of access of hyaluronidase inside the gel. Drug microreservoirs (i.e., microspheres) were incorporated in a crosslinked HA matrix. These micro-spheres could be released during degradation of the matrix. In vivo implantation experiments revealed the degradability of the HA gel in response to inflammation. Therefore, crosslinked HA gels may be promising devices as inflammation (stimulus)-responsive degradable matrices for implantable drug delivery.

生体内分解性ヒドロゲルによる炎症応答型薬物送達システム

New concept of inflammation responsive drug delivery system by biodegradable hydrogels of hyaluronic acid (HA) is reviewed. HA has been well known to be degraded specifically by the presence of hydroxyl radicals, which are produced locally at an inflammatory site. Our system is established by constructing a heterogeneous-structured device of drug microreservoirs (lipid microspheres) dispersed into the degradable matrices of crosslinked HA gel. The most attractive characteristics of this device are : (1) to performe the release of lipid microspherers in proportion to surface-controlled degradation of crosslinked HA gels, and (2) to be quantitatively inflammation-responsive degradable. These unique features of the device are favorable to regulated drug delivery to several inflammatory related diseases, where lipid microspheres can be released in response to inflammation-induced degradation although being stable under normal health conditions.