Hyaluronic acid. A review of its pharmacology and use as a surgical aid in ophthalmology, and its therapeutic potential in joint disease and wound healing

The Role of Hyaluronan Treatment in Intestinal Innate Host Defense

Hyaluronan (HA) is best known as an abundantly present extracellular matrix component found throughout the body of all vertebrates, including humans. Recent evidence, however, has demonstrated benefits of providing HA exogenously as a therapeutic modality for several medical conditions. Here we discuss the effects of providing HA treatment to increase innate host defense of the intestine, elucidate the size specific effects of HA, and discuss the role of various HA receptors as potential mediators of the HA effects in the intestine. This review especially focuses on HA interaction with the epithelium because it is the primary cellular barrier of the intestine and these cells play a critical balancing role between allowing water and nutrient absorption while excluding microbes and harmful dietary metabolites that are constantly in that organ's environment.

Different Treatments in Patients with Temporomandibular Joint Disorders: A Comparative Randomized Study

BACKGROUND AND OBJECTIVES

Temporomandibular joint disorders (TMJDs) are associated with pain and reduced jaw mobility. The aim of this study was to compare the outcome of patients with TMJ arthralgia when submitted to four different treatment modalities, in some cases using intra-articular injections of substances with anti-inflammatory properties and in others, a more conservative approach consisting only of a bite splint. Materials and Methods: The sample was made up of 80 patients, randomly distributed into 4 groups of 20 patients each. Each patient was given a nocturnal bite splint. One of the groups was treated with the bite splint only, while each patient in the other 3 was injected with betamethasone, sodium hyaluronate, or platelet-rich plasma in addition to using the bite splint. Two variables were assessed, namely pain intensity between 0 to 10 according to the visual analogue scale and maximum pain-free mouth opening in mm. The patients were evaluated at four different points: at the beginning of the treatment, as well as one week, one month and six months after initiation.

RESULTS

The results showed that maximum pain-free mouth opening improved in all the groups that made up the sample, with either a reduction in pain severity or with no pain. However, the group injected with platelet-rich plasma yielded the best results after six months, while patients treated with sodium hyaluronate or betamethasone obtained the best results at the end of the first week.

CONCLUSIONS

We concluded that all the treatments used caused a reduction in pain and increased pain-free mouth opening. The splint combined with the platelet-rich plasma injection achieved long-term success.

Effect of topically applied hyaluronic acid on pain and palatal epithelial wound healing: An examiner-masked, randomized, controlled clinical trial

BACKGROUND

This study aims to evaluate the effects of two different concentrations of topical hyaluronic acid (HA) on postoperative patient discomfort and wound healing of palatal donor sites after free gingival graft (FGG) surgery.

METHODS

Thirty-six patients requiring FGG were randomly assigned into three groups in an examiner-masked, randomized, controlled clinical trial. After harvesting palatal grafts, 0.2% and 0.8% HA gels were used in test groups 1 and 2, respectively. Gels were applied on donor sites and protected with periodontal dressing in the test groups, whereas the wound was covered only with periodontal dressing in the control group. On days 3, 7, 14, and 21, pain and burning sensation were recorded using a visual analog scale (VAS) as well as other parameters such as complete epithelization (CE) and color match on days 3, 7, 14, 21, and 42.

RESULTS

Test groups experienced less pain than the control group on days 3 and 7 (P <0.001 and P <0.001, respectively). Mean VAS score for burning sensation was higher in the control group on day 3 compared with test groups 1 and 2 (P = 0.03 and P = 0.02, respectively). CE in all patients was achieved on day 21 in both test groups, whereas it was achieved on day 42 in the control group. The test groups showed higher color match scores than the control group on days 21 (P <0.001 and P <0.001, respectively) and 42 (P = 0.004 and P = 0.002, respectively).

CONCLUSION

Topical application of HA exhibits positive impact on postoperative pain and burning sensation, and accelerates palatal wound healing in terms of epithelization and color match.

Comparison of the Effect of Two Hyaluronic Acid Preparations on Fibroblast and Endothelial Cell Functions Related to Angiogenesis

Hyaluronic acid (HA) is used in substitutive and aesthetic medicine with various applications. Ultrapure absorbable HA (Bioregen^®) and a mix of reticulated and free low molecular weight HA (Regenyal Idea Bioexpander®) (both provided by Regenyal Laboratories Srl, San Benedetto del Tronto (AP), Italy) represent a reliable hydrating device and skin filler, useful for skin blemishes, lines and wrinkles, and lip widening, respectively. The commercial products are known for their safety, but data on the molecular, cellular, and tissue responses are lacking. We aimed to evaluate the bioavailability and the pro-angiogenic features of the products Bioregen^® and Bioexpander^® in vitro on cultured endothelial cells (ECs) and dermal fibroblasts in vivo when injected into experimental animals. When added to fibroblasts and ECs, Bioexpander^® induced cell migration. The two HA preparations were well tolerated, while a transient proangiogenic behavior of Bioexpander^®, when implanted subcutaneously in mice, was found. The neovascular response was evident in the first week with higher levels of VEGF and FGF-2 before undergoing regression. In conclusion, our data strengthen the safety of HA synthetic preparations both in vitro and in vivo. Even if a proangiogenic response is documented, it is modest and transient, leading to tissue recovery and absence of an inflammatory infiltrate.

Pharmacodynamics, efficacy, safety and administration of intra-articular therapies for knee osteoarthritis

Introduction: Osteoarthritis (OA) is the leading cause of disability in the elderly, usually presenting with mono-or oligo-arthritis where local drug delivery by intra-articular (IA) injection may be more effective in terms of increased bioavailability, less systemic exposure and reduced adverse events. Several intra-articular medications for symptomatic are available on the market while the new disease-modifying drugs (DMOADs) are progressing into phase 3 pipeline of drug development.Areas covered: This narrative review covered the pharmacokinetic and pharmacodynamics of clinically available IA drugs which include corticosteroids, hyaluronic acid as well as injection techniques, efficacy, adverse effects and contraindications. In addition, the authors briefly describe the newer disease-modifying OA drugs (DMOAD) which are undergoing phase 3 pipeline of development such as Fibroblast growth factor (FGF-18) and Wnt inhibitor.Expert opinion: This is a rapidly evolving area with both new products and new trials regularly emerging. It is also a critically important area in a disease field that lacks for safe and effective treatments, where intra-articular delivery may enhance both local efficacy and reduce systemic toxicity.

Hyaluronan Accelerates Intestinal Mucosal Healing through Interaction with TSG-6

Hyaluronan (HA) has proven to be beneficial in the treatment of several diseases. Recently, it has been shown that the local application of HA (IBD98E) improves endoscopic and clinical outcomes in subjects with active distal ulcerative colitis (UC). However, the mechanisms by which this polysaccharide exerts its beneficial effects are unclear. Here, we demonstrated that HA treatment in vitro and in vivo improved mucosal healing by accelerating intestinal epithelial regeneration. Indeed, mice treated with HA showed a faster recovery from colitis and reduced endoscopic signs of mucosal inflammation compared to those receiving saline. Furthermore, histological analysis revealed less ulcerated mucosa in mice treated with HA, characterized by re-epithelialized areas. TSG-6, the secreted product of TNF-stimulated gene-6, is an HA-binding protein shown previously to have tissue-protective properties and promote wound healing. Mucosal levels of TSG-6 increased in UC patients compared to the healthy controls and also after wounding in mice. TSG-6 deletion prevented the beneficial properties of HA in mucosal wound repair, suggesting that the interaction of HA with TSG-6 is crucial for intestinal epithelial regeneration. Overall these results are consistent with HA having a therapeutic effect via the promotion of mucosal healing in patients with ulcerative colitis.

Hydrogel vehicles for sequential delivery of protein drugs to promote vascular regeneration

In recent years, as the mechanisms of vasculogenesis and angiogenesis have been uncovered, the functions of various pro-angiogenic growth factors (GFs) and cytokines have been identified. Therefore, therapeutic angiogenesis, by delivery of GFs, has been sought as a treatment for many vascular diseases. However, direct injection of these protein drugs has proven to have limited clinical success due to their short half-lives and systemic off-target effects. To overcome this, hydrogel carriers have been developed to conjugate single or multiple GFs with controllable, sustained, and localized delivery. However, these attempts have failed to account for the temporal complexity of natural angiogenic pathways, resulting in limited therapeutic effects. Recently, the emerging ideas of optimal sequential delivery of multiple GFs have been suggested to better mimic the biological processes and to enhance therapeutic angiogenesis. Incorporating sequential release into drug delivery platforms will likely promote the formation of neovasculature and generate vast therapeutic potential.

Preparation, Optimization, and Evaluation of Hyaluronic Acid-Based Hydrogel Loaded with Miconazole Self-Nanoemulsion for the Treatment of Oral Thrush

Miconazole nitrate (MZ) is a BCS class II antifungal poorly water-soluble drug with limited dissolution properties and gastrointestinal side effects. Self-nanoemulsifying delivery system-based gel of MZ can improve both solubility and oral mucosal absorption with enhanced antifungal activity. The study aims to formulate MZ self-nanoemulsion (MZ-NE) and combine it within hyaluronic acid-based gel. MZ solubility in various oils, surfactants, and cosurfactant used in NE formulations were evaluated. Mixture design was implemented to optimize the levels of NE components as a formulation variable to study their effects on the mean globule size and antifungal inhibition zones. Further, the optimized MZ-NE was loaded into a hyaluronic acid gel base. Rheological behavior of the prepared gel was assessed. Ex vivo permeability of optimized formulation across buccal mucous of sheep and inhibition against Candida albicans were examined. Mixture design was used to optimize the composition of MZ-NE formulation as 22, 67, and 10% for clove oil, Labrasol, and propylene glycol, respectively. The optimized formulation indicated globule size of 113 nm with 29 mm inhibition zone. Pseudoplastic flow with thixotropic behavior was observed, which is desirable for oral gels. The optimized formulation exhibited higher ex vivo skin permeability and enhanced antifungal activity by 1.85 and 2.179, respectively, compared to MZ-SNEDDS, and by 1.52 and 1.72 folds, respectively, compared to marketed gel. Optimized MZ-NE hyaluronic acid-based oral gel demonstrated better antifungal activity, indicating its potential in oral thrush pharmacotherapy.

Hyaluronic Acid: Molecular Mechanisms and Therapeutic Trajectory

Hyaluronic acid (also known as hyaluronan or hyaluronate) is naturally found in many tissues and fluids, but more abundantly in articular cartilage and synovial fluid (SF). Hyaluronic acid (HA) content varies widely in different joints and species. HA is a non-sulfated, naturally occurring non-protein glycosaminoglycan (GAG), with distinct physico-chemical properties, produced by synoviocytes, fibroblasts, and chondrocytes. HA has an important role in the biomechanics of normal SF, where it is partially responsible for lubrication and viscoelasticity of the SF. The concentration of HA and its molecular weight (MW) decline as osteoarthritis (OA) progresses with aging. For that reason, HA has been used for more than four decades in the treatment of OA in dogs, horses and humans. HA produces anti-arthritic effects via multiple mechanisms involving receptors, enzymes and other metabolic pathways. HA is also used in the treatment of ophthalmic, dermal, burns, wound repair, and other health conditions. The MW of HA appears to play a critical role in the formulation of the products used in the treatment of diseases. This review provides a mechanism-based rationale for the use of HA in some disease conditions with special reference to OA.

Development of a Novel Polymer-Based mRNA Coating for Surgical Suture to Enhance Wound Healing

A therapeutic strategy to improve wound healing has become an increasingly important medical task due to the rising incidence of adiposity and type II diabetes as well as the proceeding population aging. In order to cope with the resulting burdens, new strategies to achieve rapid and complete wound healing must now be developed. Accordingly, the development of a bioactive wound dressing in the form of a messengerRNA (mRNA)-bearing poly(lactide-co-glycolide acid) (PLGA) coating on surgical suture is being pushed further with this study. Furthermore, the evaluation of the polymer-based transfection reagent Viromer RED has shown that it can be used for the transfection of eukaryotic cells: The mRNA gets properly complexed and translated into a functional protein. In addition, the mRNA-PLGA coating triggered the expression of the keratinocyte growth factor (KGF) in HaCat cells although KGF is not expressed under physiological conditions. Moreover, transfection via surgical sutures coated with mRNA does not affect the cell viability and a proinflammatory reaction in the transfected cells is not induced. These properties make the mRNA-PLGA coating very attractive for the in vivo application. For the future, this could mean that through the use of mRNA-coated sutures in surgical wound closure, cells in the wound area can be transfected directly, thus accelerating and improving wound healing.

Hyaluronic Acid Combined with Serum Rich in Growth Factors in Corneal Epithelial Defects

The aim of this study is to assess if an adhesive biopolymer, sodium hyaluronate (NaHA), has synergistic effects with s-PRGF (a serum derived from plasma rich in growth factors and a blood derivative that has already shown efficacy in corneal epithelial wound healing), to reduce time of healing or posology. In vitro proliferation and migration studies, both in human corneal epithelial (HCE) cells and in rabbit primary corneal epithelial (RPCE) cultures, were carried out. In addition, we performed studies of corneal wound healing in vivo in rabbits treated with s-PRGF, NaHA, or the combination of both. We performed immunohistochemistry techniques (CK3, CK15, Ki67, ß4 integrin, ZO-1, α-SMA) in rabbit corneas 7 and 30 days after a surgically induced epithelial defect. In vitro results show that the combination of NaHA and s-PRGF offers the worst proliferation rates in both HCE and RPCE cells. Addition of NaHA to s-PRGF diminishes the re-epithelializing capability of s-PRGF. In vivo, all treatments, given twice a day, showed equivalent efficacy in corneal epithelial healing. We conclude that the combined use of s-PRGF and HaNA as an adhesive biopolymer does not improve the efficacy of s-PRGF alone in the wound healing of corneal epithelial defects.

Evaluation of a Novel Blue-Colored Ophthalmic Viscoelastic Device Applied during Phacoemulsification in Eyes with Pseudoexfoliation Syndrome

Recently, a new development in the field of ophthalmic viscoelastic devices (OVDs) has been introduced. The blue-colored OVD Pe-Ha-Blue® PLUS combines the viscoelastic properties of OVD together with trypan blue for better visualization during surgery. The objective of this case series is to investigate whether the use of a blue-colored OVD during cataract surgery in patients with pseudoexfoliation syndrome (PXF) and narrow pupils (miosis) has advantages over the use of a clear standard OVD in combination with trypan blue. We included 52 eyes of 52 consecutive cataract patients diagnosed with PXF. Study participants were divided into two groups of 26 patients each, depending on which OVD was used during surgery (group A: blue-colored OVD; group B: standard clear OVD). Intraoperatively, we evaluated the operation time (surgery start to the beginning of phacoemulsification) and the surgeon's satisfaction with the surgical workflow. Postoperative examinations were performed 6 h, 20 h, and 4 weeks after surgery and included corrected distance visual acuity (CDVA) and intraocular pressure (IOP). Our results show that there was a statistically significant time gain in group A in terms of surgery time. In addition, findings on surgeon satisfaction, postoperative CDVA and IOP suggest further benefits in group A. We discuss further properties and possible advantages which may result from the use of a blue-colored OVD. In summary, a blue-colored viscoelastic device can be a helpful alternative to clear OVD especially in challenging cases to improve the surgical workflow and make the whole procedure even safer and faster.

Methods to Induce Chronic Ocular Hypertension: Reliable Rodent Models as a Platform for Cell Transplantation and Other Therapies

Glaucoma, a form of progressive optic neuropathy, is the second leading cause of blindness worldwide. Being a prominent disease affecting vision, substantial efforts are being made to better understand glaucoma pathogenesis and to develop novel treatment options including neuroprotective and neuroregenerative approaches. Cell transplantation has the potential to play a neuroprotective and/or neuroregenerative role for various ocular cell types (e.g., retinal cells, trabecular meshwork). Notably, glaucoma is often associated with elevated intraocular pressure, and over the past 2 decades, several rodent models of chronic ocular hypertension (COH) have been developed that reflect these changes in pressure. However, the underlying pathophysiology of glaucoma in these models and how they compare to the human condition remains unclear. This limitation is the primary barrier for using rodent models to develop novel therapies to manage glaucoma and glaucoma-related blindness. Here, we review the current techniques used to induce COH-related glaucoma in various rodent models, focusing on the strengths and weaknesses of the each, in order to provide a more complete understanding of how these models can be best utilized. To so do, we have separated them based on the target tissue (pre-trabecular, trabecular, and post-trabecular) in order to provide the reader with an encompassing reference describing the most appropriate rodent COH models for their research. We begin with an initial overview of the current use of these models in the evaluation of cell transplantation therapies.

A hyaluronic acid- and chondroitin sulfate-based medical device improves gastritis pain, discomfort, and endoscopic features

Gastritis is an inflammation of the gastric mucosa. In this study, we investigated the efficacy of a medical device, Esoxx®, based on hyaluronic acid and chondroitin sulfate on gastritis-related upper abdominal pain/discomfort and endoscopic features. Fifty patients, affected by gastritis, were randomised to receive the medical device or placebo. The primary endpoint was the medical device efficacy on upper abdominal pain/discomfort associated with gastritis and measured by Visual Analogue Scale (VAS). The secondary endpoints were the efficacy of the medical device on gastritis-related mucosal erosions, blood oozing, and hyperemia (redness)/edema, as assessed by endoscopy, and the patients’ rating of their compliance with the treatments. A significant reduction in VAS pain was observed in the treatment group after a 5-week treatment, if compared with placebo (p < 0.001). In summary, administration of a medical device, based on hyaluronic acid and chondroitin sulfate, improves gastritis-related upper abdominal pain/discomfort and decreases mucosal erosions, blood oozing, and hyperemia (redness)/edema at 5-week follow-up in patients affected by gastritis.

Evaluation of the In Vivo Kinetics and Biostimulatory Effects of Subcutaneously Injected Hyaluronic Acid Filler

BACKGROUND

Because subcutaneously injected hyaluronic acid filler is absorbed over 6 months to 1 year after the treatment of facial wrinkles, frequent retreatment may be required. However, persistent long-term effects are often clinically observed when hyaluronic acid filler is injected as a bolus for facial augmentation. Therefore, the authors investigated, over time, the changes in volume and histologic features of subcutaneous bolus injections of hyaluronic acid.

METHODS

Hyaluronic acid filler was subcutaneously injected as a bolus into the dorsum of 6-week-old rats. At several time points (immediately after injection and 4, 8, 16, 32, and 64 weeks thereafter), magnetic resonance imaging was introduced to observe morphologic changes and to measure volume. Histologic examination of sectioned tissues was also performed.

RESULTS

The average volume increased for up to 4 weeks after injection and then gradually decreased, with 74.8 percent of the injected volume remaining after 64 weeks, with no statistical difference compared to the initial volume. Histologic analysis revealed that lattice structures were created by fibroblasts and collagen fibers, and blood vessels and adipocytes were also generated in the filler.

CONCLUSIONS

Although subcutaneous bolus injections of hyaluronic acid filler exhibited flattening, the total volume was maintained even after 64 weeks. Histologically, hyaluronic acid filler acted as a scaffold for autogenous tissue replacement by means of fibroblast migration and proliferation, collagen induction, and angiogenesis, followed by proliferation of adipocytes. This study demonstrates that the total volume is maintained long-term by replacing part of the injected hyaluronic acid filler with autologous tissues.

Application of thermoreversible hydrogel (poloxamer 407) to protect the corneal endothelium during phacoemulsification in porcine and rabbit eyes

PURPOSE

To evaluate the effectiveness of thermoreversible (poloxamer) hydrogels as a substitute for ophthalmic viscosurgical devices (OVDs) during phacoemulsification in porcine and rabbit eyes and compare their endothelial protective effect with that of hyaluronic acid-based OVDs.

SETTING

Department of Ophthalmology, Seoul Metropolitan Government-Seoul National University Boramae Medical Center, Seoul, South Korea.

DESIGN

Experimental study.

METHODS

Fluorescein-stained poloxamer hydrogels (20%, 22%, 24%, and 26% [weight/weight%]) and cohesive (sodium hyaluronate 1.0% [Provisc]) and dispersive (sodium hyaluronate 3.0%-chondroitin sulfate 4.0% [Viscoat]) OVDs were injected into the anterior chamber of porcine eyes incubated at 32°C. In the in vitro study, the retention time was measured in 3 groups of 45 porcine eyes during continuous phacoemulsification. In the in vivo study, the endothelial cell count (ECC) was measured before and 3 days after intermittent phacoemulsification in 12 rabbit eyes randomized to a poloxamer hydrogel or a dispersive OVD group.

RESULTS

The optimum concentration of thermosensitive hydrogel was 26%, at which no gel-to-sol phase transition occurred in the anterior chamber, with a 21°C irrigation solution. In the in vitro study, the mean retention times were 5.53 seconds ± 1.77 (SD), 125.00 ± 29.34 seconds, and 221.53 ± 42.48 seconds in the cohesive OVD, dispersive OVD, and 26% poloxamer hydrogel groups, respectively (P < .001). Throughout the 5-minute intermittent phacoemulsification, the 26% poloxamer hydrogel remained in the anterior chamber as a semisolid gel. In the in vivo study, the mean decrease in ECC was significantly lower in the 26% poloxamer hydrogel group than in the dispersive OVD group (P = .029).

CONCLUSION

Thermoreversible hydrogels might be suitable substitutes for hyaluronic acid-based OVDs for corneal endothelial protection during phacoemulsification.

Outcome of fixed volume intracameral sodium hyaluronate 1.4% injection for early postoperative hypotony after Baerveldt glaucoma implant

IMPORTANCE

Using an ophthalmic viscoelastic device to manage early postoperative hypotony after Baerveldt glaucoma implant (BGI).

BACKGROUND

To determine the outcome of intracameral sodium hyaluronate injection for early postoperative hypotony treatment after BGI.

DESIGN

A retrospective study.

PARTICIPANTS

One-hundred-and-thirty-eight patients (176 eyes) had BGI from January 2012 to November 2015. Those who had hypotony within 3 months postoperatively were studied.

METHODS

Hypotonous eyes were injected with 0.1 mL sodium hyaluronate 1.4% intracameral on the slit-lamp. The patients were followed up weekly and the injection repeated up to 3 times if hypotony persisted. The tube was tied surgically as a last resort.

MAIN OUTCOME MEASURES

The intraocular pressure and best-corrected visual acuity at week 1, 2, 3, 4, 6 and month 4 were assessed.

RESULTS

Thirty (17.0%) out of 176 eyes developed early postoperative hypotony. The median intraocular pressure and median best-corrected visual acuity when hypotony first presented were 3 mmHg and 0.8 logMAR. Two eyes were excluded as they had more than 0.1 mL injection. Eight (29%) of the 28 hypotonous eyes resolved after one injection, seven (25%) required two and 10 (36%) needed three injections. Three (11%) eyes had surgical tube tie. The median intraocular pressures were 5, 7, 8, 10, 11 and 13 mmHg at week 1, 2, 3, 4, 6 and month 4 post-injection. The median best-corrected visual acuity were 0.60, 0.50, 0.50, 0.45, 0.40 and 0.40 logMAR for the same period.

CONCLUSIONS AND RELEVANCE

Standardised intracameral 0.1 mL sodium hyaluronate 1.4% is an effective and safe way to manage early postoperative hypotony after BGI.

Metabolic engineering to enhance heterologous production of hyaluronic acid in Bacillus subtilis

Hyaluronic acid (HA) is a high-value biopolymer that is produced in large scales using attenuated strains ofgroup C streptococci. However, due to the pathogenicity and fastidious nature of these bacteria, the development of bioprocesses for HA production centered on robust 'Generally Recognized as Safe (GRAS)' organisms, such as Bacillus subtilis, is of increased interest. Here, we report metabolic engineering of novel B. subtilis strains in which the carbon flux has been partially diverted from central metabolism, i.e. the pentose phosphate pathway (PPP) and glycolysis, into HA biosynthesis. First, an improved base strain of B. subtilis was engineered for more effective HA production with less susceptibility to catabolite repression when expressing genes from a xylose-inducible promoter. Subsequently, Clustered Regularly Interspaced Palindromic Repeats interference (CRISPRi) was applied to reduce the expression of individual pfkA or zwf in the base strain, leading to substantial improvements to the HA titer with a concomitant decrease in the molecular weight (MW). On the other hand, multiplexed repression of both pfkA and zwf expression resulted in increases to the HA titer of up to 108% and enhancements to the MW, compared to the base strain. Moreover, the addition of exogenous HA monomers, i.e. glucuronic acid (GlcUA) and N-acetyl-glucosamine (GlcNAc), to B. subtilis cultures markedly improved the HA MW but decreased the HA titer, providing insights into the mechanism of HA biosynthesis by streptococcal hyaluronan synthase (SeHAS) in B. subtilis. Our study demonstrates the successful application of metabolic engineering strategies to establish B. subtilis as an effective platform for high-level HA production.

Efficacy of Sodium Hyaluronate in Murine Diabetic Ocular Surface Diseases

Supplemental Digital Content is Available in the Text.

Purpose:

To evaluate the efficacy of sodium hyaluronate (HA) eye drops for the treatment of diabetic ocular surface diseases in mice.

Methods:

Male 6- to 8-week-old C57BL/6 mice underwent induction of type 1 diabetes with intraperitoneal injections of streptozotocin, with normal mice as the control. Topical 0.3% HA, 0.1% HA, 0.4% polyethylene glycol eye drops, and normal saline were administered to diabetic mice with an intact or debrided corneal epithelium. Normal saline was applied in the controls. Corneal epithelial wound healing rate, corneal sensation, nerve fiber density, conjunctival goblet cell number, and MUC-5AC content were measured and compared.

Results:

Compared with the controls, topical 0.3% HA use in diabetic mice showed significant improvements in the corneal epithelial wound healing rate (48 hours: 91.5% ± 4.8% vs. 79.8% ± 6.1%; P < 0.05), corneal sensitivity (4.1 ± 0.3 cm vs. 3.5 ± 0.3 cm; P < 0.05), nerve fiber density (12.9% ± 2.3% vs. 6.6% ± 2.4%; P < 0.05), conjunctival goblet cell number (31.0 ± 8.4/100 μm vs. 19.6 ± 7.1/100 μm; P < 0.05), and MUC-5AC content (12.5 ± 1.4 ng/mg vs. 7.8 ± 1.5 ng/mg protein; P < 0.05). The beneficial effects of 0.3% HA were better than those of 0.1% HA and 0.4% polyethylene glycol.

Conclusions:

Topical 0.3% HA treatment promoted corneal epithelial regeneration, improved corneal sensation, and increased density of corneal nerve fibers and conjunctival goblet cells in mice with diabetic ocular surface diseases.

Combination of hyaluronic acid, carmellose, and osmoprotectants for the treatment of dry eye disease

Background

Dry Eye Disease (DED) is a multifactorial disease, with a high prevalence, that can have a great impact on the quality of life of patients. The first step of treatment includes the use of lacrimal substitutes composed of polymers, possible to associate osmoprotectant agents to the lacrimal substitutes. The aim of this article is to analyze the properties of the combination of hyaluronic acid (HA), carmellose, and osmoprotectors (Optava Fusion^®; Allergan, Inc., Irvine, CA, USA) on DED. General considerations on the use of artificial tears are also proposed.

Methods

A group of ophthalmologists, experts in the management of the ocular surface, analyzed different aspects related to DED; among them, the use of artificial tears in general and the properties of the combination of HA, carmellose, and osmoprotectors, in particular, were discussed. A review of the literature was carried out, which included different articles published in Spanish, English, and French until April 2017.

Conclusions

DED is a common chronic pathology that usually requires sustained treatment. In addition, the combination of HA, carmellose, and osmoprotectors has proven to be effective in the treatment of symptoms and signs of dry eye by the synergistic action of all its components. This review provides key elements to help ophthalmologists who begin in the management of DED.

Comparative Effectiveness of Intra-Articular Hyaluronic Acid and Corticosteroid Injections on the Time to Surgical Knee Procedures

BACKGROUND

Use of intra-articular hyaluronic acid (HA) injections to manage knee osteoarthritis (OA) remains controversial because of weak and conflicting evidence. The objective was to evaluate the effectiveness of intra-articular HA injections for knee OA management.

METHODS

A nested cohort of persons with knee OA seeing a specialist was created using a 10% random sample of LifeLink Plus claims (2010-2015) to compare the risk of composite (any) knee surgical interventions, total (TKA)/unicompartmental knee arthroplasty (UKA) and TKA only among HA users and 2 comparison groups: corticosteroid (CS) users and HA/CS nonusers. A high-dimensional propensity score (hdPS) was used to match HA users with CS users and with HA/CS nonusers on background covariates. The risk of surgical interventions among HA users relative to the comparison groups was assessed using Cox proportional hazard models.

RESULTS

Among 13,849 patients, 797 were HA users, 5327 were CS users, and 7725 were HA/CS nonusers. After hdPS matching, the risk of composite surgical interventions did not differ between HA users and HA/CS nonusers (hazard ratio [HR], 0.88; 95% confidence interval [CI], 0.67-1.16) and CS users (HR, 0.89; 95% CI, 0.65-1.12). Seven of the 8 sensitivity analyses demonstrated no significant benefit among HA users compared to CS users and HA/CS nonusers. A sensitivity analysis that restricted the study cohort to those who ultimately have knee surgery showed a lower risk of surgery of HA (HR, 0.87; 95% CI, 0.79-0.95).

CONCLUSION

There were no significant differences in the risk of surgical interventions among HA users compared to HA/CS nonusers and CS users after accounting for residual confounding using an hdPS.

[Hyaluronic acid gels for pressure regulation in glaucoma treatment]

BACKGROUND

The increasing numbers of glaucoma patients and complications occuring during treatment, such as restenosis and hypotony, require new treatment options to prevent blindness in patients. Therefore, the abovementioned problems should be solved to prolong the lifetime of implants and to prevent repeated surgery.

OBJECTIVE

Can a novel stent with hyaluronic acid hydrogels (HA gel) as a functional unit be used to regulate pressure in glaucoma therapy in the long term?

MATERIAL AND METHODS

Model stents were filled with HA gels and it was investigated if these could regulate the pressure and what the underlying mechanism is.

RESULTS

The results of the investigations showed that the HA gel inside the stent functions as a pressure valve. Under certain equilibrium pressures the HA gel closes the stent and therefore retains the fluid. At a certain overpressure the HA gel enables the fluid to be released and leads to a self-regulated adjustment of the equilibrium pressure.

DISCUSSION

The next step will involve miniaturization of the stents. Experiments will then show if the valve function will also work in the dimensions necessary for an eye implant and if the current problem of hypotension in glaucoma therapy can be solved.

Evaluation of gelatin-hyaluronic acid composite hydrogels for accelerating wound healing

Excellent wound dressings maintain a warm and moist environment, thus accelerating wound healing. In this study, we cross-linked gelatin and hyaluronic acid with ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride in different ratios (gelatin/hyaluronic acid = 8:2, gelatin/hyaluronic acid = 5:5, gelatin/hyaluronic acid = 2:8), and explored the effects and mechanisms of gelatinhyaluronic acid hydrogels on wound healing. This was done by examining dressing properties, such as fluid uptake ability, water vapor transmission rate, and the rate of water evaporation. We further verified biological function by using in vitro and in vivo wound models. The hydrogels display appropriate fluid uptake ability and good water vapor transmission rate and rate of water evaporation all of which can provide an adequate moisture environment for wound healing. Cell cytotoxicity and proliferation tests show that the hydrogels have no cytotoxicity, furthermore, gelatin/hyaluronic acid = 8:2 hydrogels have the potential to promote cell proliferation. Animal wound models demonstrate that the hydrogels can effectively promote wound healing in vivo, in particular, the gelatin/hyaluronic acid = 8:2 group which promoted the most rapid healing. Accordingly, gelatin-hyaluronic acid dressings, especially the gelatin/hyaluronic acid = 8:2 hydrogels, have a promising outlook for clinical applications in wound healing.

Hyaluronic acid for post sinus surgery care: systematic review and meta-analysis

BACKGROUND

Wound healing after endoscopic sinus surgery may result in adhesion formation. Hyaluronic acid may prevent synechiae development. A systematic review was performed to evaluate the current evidence on the clinical efficacy of hyaluronic acid applied to the nasal cavity after sinus surgery.

METHODS

Studies using hyaluronic acid as an adjunct treatment following endoscopic sinus surgery for chronic rhinosinusitis were identified. The primary outcome was adhesion formation rates. A meta-analysis was performed on adhesion event frequency. Secondary outcome measures included other endoscopic findings and patient-reported outcomes.

RESULTS

Thirteen studies (501 patients) met the selection criteria. A meta-analysis of adhesion formation frequency on endoscopy demonstrated a lower risk ratio in the hyaluronic acid intervention group (42 out of 283 cases) compared to the control group (81 out of 282) of 0.52 (95 per cent confidence interval = 0.37-0.72). Hyaluronic acid use was not associated with any significant adverse events.

CONCLUSION

Hyaluronic acid appears to be clinically safe and well tolerated, and may be useful in the early stages after sinus surgery to limit adhesion rate. Further research, including larger randomised controlled trials, is required to evaluate patient- and clinician-reported outcomes of hyaluronic acid post sinus surgery.

Hyaluronic Acid/PLGA Core/Shell Fiber Matrices Loaded with EGCG Beneficial to Diabetic Wound Healing

During the last few decades, considerable research on diabetic wound healing strategies has been performed, but complete diabetic wound healing remains an unsolved problem, which constitutes an enormous biomedical burden. Herein, hyaluronic acid (HA)/poly(lactic-co-glycolic acid, PLGA) core/shell fiber matrices loaded with epigallocatechin-3-O-gallate (EGCG) (HA/PLGA-E) are fabricated by coaxial electrospinning. HA/PLGA-E core/shell fiber matrices are composed of randomly-oriented sub-micrometer fibers and have a 3D porous network structure. EGCG is uniformly dispersed in the shell and sustainedly released from the matrices in a stepwise manner by controlled diffusion and PLGA degradation over four weeks. EGCG does not adversely affect the thermomechanical properties of HA/PLGA-E matrices. The number of human dermal fibroblasts attached on HA/PLGA-E matrices is appreciably higher than that on HA/PLGA counterparts, while their proliferation is steadily retained on HA/PLGA-E matrices. The wound healing activity of HA/PLGA-E matrices is evaluated in streptozotocin-induced diabetic rats. After two weeks of surgical treatment, the wound areas are significantly reduced by the coverage with HA/PLGA-E matrices resulting from enhanced re-epithelialization/neovascularization and increased collagen deposition, compared with no treatment or HA/PLGA. In conclusion, the HA/PLGA-E matrices can be potentially exploited to craft strategies for the acceleration of diabetic wound healing and skin regeneration.

A Review of Injectable Polymeric Hydrogel Systems for Application in Bone Tissue Engineering

Biodegradable, stimuli-responsive polymers are essential platforms in the field of drug delivery and injectable biomaterials for application of bone tissue engineering. Various thermo-responsive hydrogels display water-based homogenous properties to encapsulate, manipulate and transfer its contents to the surrounding tissue, in the least invasive manner. The success of bioengineered injectable tissue modified delivery systems depends significantly on their chemical, physical and biological properties. Irrespective of shape and defect geometry, injectable therapy has an unparalleled advantage in which intricate therapy sites can be effortlessly targeted with minimally invasive procedures. Using material testing, it was found that properties of stimuli-responsive hydrogel systems enhance cellular responses and cell distribution at any site prior to the transitional phase leading to gelation. The substantially hydrated nature allows significant simulation of the extracellular matrix (ECM), due to its similar structural properties. Significant current research strategies have been identified and reported to date by various institutions, with particular attention to thermo-responsive hydrogel delivery systems, and their pertinent focus for bone tissue engineering. Research on future perspective studies which have been proposed for evaluation, have also been reported in this review, directing considerable attention to the modification of delivering natural and synthetic polymers, to improve their biocompatibility and mechanical properties.

Catheter-guided suprachoroidal buckling of rhegmatogenous retinal detachments secondary to peripheral retinal breaks

PURPOSE

To evaluate functional and anatomic outcomes of eyes undergoing suprachoroidal buckling (SCB) using a specially designed catheter for the management of rhegmatogenous retinal detachment (RRD) secondary to peripheral retinal breaks.

METHODS

Retrospective cohort study of 62 eyes of 62 patients. Subjects underwent SCB for the management of RRD secondary to single or multiple retinal breaks. Suprachoroidal indentation was achieved through the introduction of viscoelastic material in the suprachoroidal space overlying the break using an illuminated, 450 μm-wide, flex-tip catheter. This allowed for the creation of a suprachoroidal dome and chorio-retinal apposition. Forty-seven eyes (80 %) underwent SCB alone, while 15 eyes (20 %) were combined with 25-G pars-plana vitrectomy. Cryopexy and laserpexy were used in 38 (61 %) and 24 of eyes (39 %) respectively.

RESULTS

Mean pre-operative best-corrected visual acuity (BCVA) improved from logMAR 0.82 (20/132) to 0.22 (20/33) (p < 0.0001). The single surgery reattachment rate was 92 % (57/62.) Final retinal reattachment was achieved in all eyes (100 %). No significant difference was observed in single-surgery anatomic success rates when stratified by lens status, macular involvement, or break location. There were no major intra- or post-operative complications.

CONCLUSION

Suprachoroidal buckling using a special-design, flexible catheter is a safe and effective procedure for the management of RRD secondary to peripheral retinal breaks.

Intra-Articular Hyaluronic Acid Compared to Traditional Conservative Treatment in Dogs with Osteoarthritis Associated with Hip Dysplasia

The purpose of this study was to compare the efficacy of the intra-articular (IA) hyaluronic acid injection to traditional conservative treatment (TCT) in dogs with osteoarthritis (OA) induced by hip dysplasia. Sixteen dogs were distributed into two groups: Hyal: IA injection of hyaluronic acid (5-10 mg), and Control: IA injection with saline solution (0.5-1.0 mL) in combination with a TCT using an oral nutraceutical (750-1000 mg every 12 h for 90 days) and carprofen (2.2 mg/kg every 12 h for 15 days). All dogs were assessed by a veterinarian on five occasions and the owner completed an assessment form (HCPI and CPBI) at the same time. The data were analyzed using unpaired t test, ANOVA, and Tukey's test (P < 0.05). Compared with baseline, lower scores were observed in both groups over the 90 days in the veterinarian evaluation, HCPI, and CPBI (P < 0.001). The Hyal group exhibited lower scores from 15 to 90 and 60 to 90 days, in the CBPI and in the veterinarian evaluation, respectively, compared to the Control group. Both treatments reduced the clinical signs associated with hip OA. However, more significant results were achieved with intra-articular hyaluronic acid injection.

Tools of gene transfer applied to the intracellular delivery of non-nucleic acid polyanionic drugs

We report the first successful implementation of transfection agents to facilitate the delivery of non-nucleic acid based anti-inflammatory and anti-viral drugs. In doing so, we illustrate a new paradigm in the intracellular delivery of polyanionic drugs and also extend the scope and utility of successful tools of gene transfer into a new area of biomedical research.

Effect of Carboxymethylation on the Rheological Properties of Hyaluronan

Chemical modifications made to hyaluronan to enable covalent crosslinking to form a hydrogel or to attach other molecules may alter the physical properties as well, which have physiological importance. Here we created carboxymethyl hyaluronan (CMHA) with varied degree of modification and investigated the effect on the viscosity of CMHA solutions. Viscosity decreased initially as modification increased, with a minimum viscosity for about 30-40% modification. This was followed by an increase in viscosity around 45-50% modification. The pH of the solution had a variable effect on viscosity, depending on the degree of carboxymethyl modification and buffer. The presence of phosphates in the buffer led to decreased viscosity. We also compared large-scale production lots of CMHA to lab-scale and found that large-scale required extended reaction times to achieve the same degree of modification. Finally, thiolated CMHA was disulfide crosslinked to create hydrogels with increased viscosity and shear-thinning aspects compared to CMHA solutions.

Note: Biological Activity of C6-Oxidized Hyaluronic Acid: Antibacterial Properties of the Zn(II) Salt

Partially oxidized hyaluronan sodium and zinc salts and hyaluronan zinc salts were prepared. The antibacterial activity of hyaluronic acid and of C(6)-oxidized hyaluronic acid zinc salts (HAZn+2 and HAOXZn+2) were evaluated against Pseudomonas aeruginosa, Staphylococcus aureus and Escherichia coli bacterial strains. HAOXZn+2 showed a higher antibacterial effect than HAZn+2 with E. coli and S. aureus; however, neither zinc salt was not able to promote any antiseptic activity against P. aeruginosa.

Collagenase From Vibrio alginolyticus Cultures: Experimental Study and Clinical Perspectives

Purpose The purpose of this study is to examine the activity of collagenase from cultures of Vibrio alginolyticus as in vitro as in biological samples and to evaluate clinical perspectives of this product about the treatment of fibroproliferative diseases like Dupuytren's contracture. Methods The experimental part of the study has been divided in 2 stages. In the first stage, the collagenase has been produced in laboratory, assessing its purity, verifying the in vitro degradation of collagen by the enzyme and measuring the size of the fragments; in the second part, an experimental injection into samples of fibrous cord typical of Dupuytren's disease has been performed in vitro. For the injection we used only collagenase, or collagenase after having subjected them to 2 types of mechanical stress or a collagenase combined with ethylenediamine tetra-acetic acid. Considering that the human samples have been treated in vitro, our institution does not require a specific informed consent. Results It appeared evident that the collagenase obtained from Vibrio alginolyticus (nonpathogenic bacterium) is highly pure (>98%) and does not contain nonspecific protease. The collagenase from Vibrio alginolyticus therefore has an excellent degradative capacity against the collagen and this activity takes on a dose- and time-dependent behavior. The collagenase from Vibrio alginolyticus does not act negatively on cell survival and collagen peptides obtained may provide a better proliferative stimulus compared to controls. Conclusions The collagenase from Vibrio alginolyticus, given its obvious ability in vitro and biological samples, could be an option in the nonsurgical treatment of Dupuytren's disease. Level of evidence Level III, therapeutic.

Effect of a hyaluronic acid and carboxymethylcellulose ophthalmic solution on ocular comfort and tear-film instability after cataract surgery

PURPOSE

To evaluate the efficacy and safety of using sodium hyaluronate 0.1% and carboxymethylcellulose 0.5% artificial tears for ocular discomfort and tear-film stability in eyes after cataract surgery.

SETTING

Twenty ophthalmic centers in Italy.

DESIGN

Prospective randomized case series.

METHODS

This study enrolled patients scheduled for unilateral cataract surgery. After surgery, patients received artificial tears and a topical steroid-antibiotic (study group) or topical steroid-antibiotic alone (control group) and were assessed postoperatively at 1 and 5 weeks. Outcome measures were tear breakup time (TBUT), ocular surface disease index (OSDI), frequency of dry-eye symptoms evaluated using a visual analog scale (VAS), and corneal fluorescein staining.

RESULTS

The study comprised 282 patients. At 5 weeks, the mean TBUT was statistically significantly higher in the study group than in the control group (P = .0003). The mean OSDI score statistically significantly improved in both groups from 1 to 5 weeks (P < .0001 for both groups); however, there was no statistically significant difference between the groups at these timepoints. The artificial tears statistically significantly improved VAS-assessed dry-eye symptoms in the study group compared with the control group at 5 weeks (P < .001). The mean corneal fluorescein staining was significantly reduced in the study group compared with the control group at 5 weeks (P = .002 versus P = .05, respectively). No treatment-related adverse events were reported.

CONCLUSION

Sodium hyaluronate 0.1% and carboxymethylcellulose 0.5% ophthalmic solution was effective and well tolerated in reducing dry-eye disease symptoms and improving the clinical outcome after cataract surgery.

FINANCIAL DISCLOSURE

No author has a financial or proprietary interest in any material or method mentioned.

Strategies to Maximize the Potential of Marine Biomaterials as a Platform for Cell Therapy

Marine biopolymers have been explored as a promising cell therapy system for efficient cell delivery and tissue engineering. However, the marine biomaterial-based systems themselves have exhibited limited performance in terms of maintenance of cell viability and functions, promotion of cell proliferation and differentiation as well as cell delivery efficiency. Thus, numerous novel strategies have been devised to improve cell therapy outcomes. The strategies include optimization of physical and biochemical properties, provision of stimuli-responsive functions, and design of platforms for efficient cell delivery and tissue engineering. These approaches have demonstrated substantial improvement of therapeutic outcomes in a variety of research settings. In this review, therefore, research progress made with marine biomaterials as a platform for cell therapy is reported along with current research directions to further advance cell therapies as a tool to cure incurable diseases.

Interdental papilla loss: treatment by hyaluronic acid gel injection: a case series

OBJECTIVES

The purpose of this prospective clinical trial was to examine the clinical and patient outcomes following esthetic reconstruction of interdental papilla loss in anterior teeth, using an injectable, non-animal-based, hyaluronic acid gel.

MATERIALS AND METHODS

Ten systemically healthy adults, with at least one anterior site with class I or II interdental papilla loss, were recruited. Following local anesthesia, ∼0.2 ml of hyaluronic acid gel was injected directly into the base of the papilla. The injection was repeated twice 21 days later. Patients were seen monthly for follow-up. Lost papilla surface area was calculated from digital clinical photographs taken at baseline and at 4 and 6 months postoperatively. Differences in lost papilla surface area between baseline and postoperative time points were statistically analyzed. Participants completed questionnaires (satisfaction surveys).

RESULTS

Seventeen sites (13 maxillary, 4 mandibular) were treated in 9 females who completed the study. The lost inderdental papilla area at baseline and at the 4- and 6-month postoperative visits was 1.2 ± 1.8 mm(2) (mean ± SD), 0.6 ± 0.9 mm(2), and 0.7 ± 0.7 mm(2), respectively. Differences between baseline and postoperative visits were statistically significant (p < 0.0001). Two thirds of the patients would choose to undergo the procedure again.

CONCLUSIONS

Use of hyaluronic acid gel to treat interdental papilla loss resulted in significant improvement at 6 months. Patients expressed satisfaction with the obtained improvement and dissatisfaction with the associated procedure discomfort.

CLINICAL RELEVANCE

Treatment of interdental papilla loss (black triangle) by hyaluronic acid gel injection appears a promising modality to address this esthetic patient concern.

Investigating triazine-based modification of hyaluronan using statistical designs

Hyaluronan (HA) and its derivatives have been extensively researched for many biomedical applications. To precisely tailor the property of HA by derivatizing it to a pre-determined extent is challenging, yet critical. In this paper, we used 2-chloro-4,6-dimethoxy-1,3,5-triazine (CDMT) and N-methylmorpholine (NMM) to derivatize HA via a triazine-based coupling reaction. Using a fractional factorial (FF) design, we observed that water content in the solvent, and molar ratios of CDMT and NaHCO3 to the carboxylate were the significant factors controlling the derivatization. We investigated how the effect of each factor changes as reaction conditions change. Moreover, by altering the amount of CDMT and NaHCO3, we developed a cubic regression model for precise control of the extent of derivatization using a response surface methodology (RSM) with a D-optimal design. No spurious peaks were detected by (1)H NMR spectrum and only 10% decrease of molecular weight of the derivatized HA was determined by GPC. The HA with 6% modification was relatively biocompatible up to 15 mg/mL.

Hyaluronan Synthase: The Mechanism of Initiation at the Reducing End and a Pendulum Model for Polysaccharide Translocation to the Cell Exterior

Hyaluronan (HA) biosynthesis has been studied for over six decades, but our understanding of the biochemical details of how HA synthase (HAS) assembles HA is still incomplete. Class I family members include mammalian and streptococcal HASs, the focus of this review, which add new intracellular sugar-UDPs at the reducing end of growing hyaluronyl-UDP chains. HA-producing cells typically create extracellular HA coats (capsules) and also secrete HA into the surrounding space. Since HAS contains multiple transmembrane domains and is lipid-dependent, we proposed in 1999 that it creates an intraprotein HAS-lipid pore through which a growing HA-UDP chain is translocated continuously across the cell membrane to the exterior. We review here the evidence for a synthase pore-mediated polysaccharide translocation process and describe a possible mechanism (the Pendulum Model) and potential energy sources to drive this ATP-independent process. HA synthases also synthesize chitin oligosaccharides, which are created by cleavage of novel oligo-chitosyl-UDP products. The synthesis of chitin-UDP oligomers by HAS confirms the reducing end mechanism for sugar addition during HA assembly by streptococcal and mammalian Class I enzymes. These new findings indicate the possibility that HA biosynthesis is initiated by the ability of HAS to use chitin-UDP oligomers as self-primers.

Effectiveness of hyaluronic acid in post-tonsillectomy pain relief and wound healing: a prospective, double-blind, controlled clinical study

OBJECTIVES

To find the effectiveness of hyaluronic acid in post-tonsillectomy pain relief and wound healing.

METHODS

Fifty patients were included in this prospective, double-blind, controlled clinical study (20 males, 30 females mean age of 13.56 years). Hyaluronic acid was applied to one side and the other side was used as a control during tonsillectomy. Therefore, the same patient evaluated and scored the post-tonsillectomy pain, excluding individual bias.

RESULTS

Results indicated that patients had significantly lower pain scores for hyaluronic acid treated side (p<0.001). At the end of two weeks follow-up period, the wound in the hyaluronic acid side was almost completely healed, indicating that the healing was faster with hyaluronic acid compared to control side (p<0.001).

CONCLUSION

Hyaluronic acid could be recommended as an effective treatment for the management of post-tonsillectomy pain and wound healing.