Healing of hyaluronic acid-enriched wounds: histological observations

Comparative Study of the Efficacy of EHO-85, a Hydrogel Containing Olive Tree (Olea europaea) Leaf Extract, in Skin Wound Healing

Olive tree (Olea europaea) leaf extract (OELE) has important antioxidant and anti-inflammatory properties, supporting its use in human clinical practice. We recently designed an amorphous hydrogel called EHO-85 (EHO indicates olive leaf extract in Spanish) containing OELE for skin ulcer treatments. Yet, its effectiveness has not been previously compared with other products used in routine clinical practice. This is necessary to evaluate its potential translation to the human clinic. Thus, in this study, the effect of EHO-85 on healing was evaluated in comparison with treatments containing Indian/Asiatic pennywort (Centella asiatica), hyaluronic acid, or dexpanthenol in a rat model. The speed of wound closure and histological parameters after seven and 14 days were analyzed. All treatments accelerated wound closure, but there were differences between them. Dexpanthenol after seven days produced the highest epithelialization and the lowest inflammation and vascularization. EHO-85 also promoted epithelialization and reduced vascularization. After 14 days, wounds treated with EHO-85 showed less inflammation and higher levels of collagen in the extracellular matrix. This indicates a higher degree of maturity in the regenerated tissue. In conclusion, the effect of EHO-85 on healing was equal to or superior to that of other treatments routinely used in human clinical practice. Therefore, these results, together with previous data on the effects of this hydrogel on ulcer healing in humans, indicate that EHO-85 is a suitable, low-cost, and efficient therapeutic option for wound healing.

Hyaluronic Acid-Cellulose Composites as Patches for Minimizing Bacterial Infections

A facile method was used to synthesize biocomposites containing differing ratios of hyaluronic acid (HA) and cellulose (CEL). Based on the properties of the individual polymers, the resultant composite materials may have potentially great wound care properties. In the method outlined here, 1-butyl-3-methylimidazolium chloride ([Bmim][Cl]), a simple ionic liquid, was used as the sole solvent without chemical modifiers to dissolve the biopolymers at ratios of 1:1 and 2:1 HA to CEL. This method was completely recyclable since the ionic liquid, [Bmim][Cl], can be recovered. Results from spectroscopic measurements [Fourier transform infrared (FT-IR) and X-ray diffraction (XRD)] confirm the interaction between HA and CEL. Scanning electron microscopy (SEM) images reflect differing biopolymer ratios and the resulting impact on the texture and porosity of these composite materials. The composites exhibited high swelling capacity in various media. These composites were also drug-loaded to examine drug release properties for greater potential in combating Staphylococcus aureus infections.

N-Acetylglucosamine Changes Permeability of Peritoneum during Chronic Peritoneal Dialysis in Rats

Objective

To evaluate the effect of supplementation of dialysis fluid with N-acetylglucosamine (NAG) on the permeability of peritoneum during chronic peritoneal dialysis in rats.

Design

Experiments were performed on rats with surgically implanted peritoneal catheters. Dialysis solution [DianeaI1.5% (Baxter, Deerfield, IL, U.S.A.) supplemented with either NAG 50 mmol/L or glucose 50 mmol/L (control)] was infused intraperitoneally twice, every day, for 8 weeks. Peritoneal equilibration tests (PET) were performed in all animals at the beginning of the study and after 8 weeks of dialysis. Additionally, at the end of each week, dialysis solution infused in the morning was drained after 4 hours of intraperitoneal dwell. White blood cell count, creatinine, and total protein concentrations were measured in the effluent dialysate. After 8 weeks of dialysis, the morphology of the peritoneum was studied.

Results

In rats exposed to dialysis fluid supplemented with NAG, peritoneal permeability to creatinine and proteins was reduced when compared to animals dialyzed with glucose solution. In NAG treated animals, staining with alcian blue for polyanions in the peritoneal interstitium was significantly stronger than in rats dialyzed with glucose solution.

Conclusions

Chronic peritoneal dialysis with dialysis solution supplemented with N-acetylglucosamine causes accumulation of glycosaminoglycans in the peritoneal interstitium, which results in a change of peritoneal permeability.

The receptor for hyaluronan-mediated motility (RHAMM) expression in neonatal bronchiolar epithelium correlates negatively with lung air content

INTRODUCTION

Hyaluronan (HA) and the receptor for hyaluronan-mediated motility (RHAMM) may play an important role in lung development. We examined the expression of HA content and RHAMM during postnatal lung development by analyzing human lung specimens from newborn infants with a variety of lung diseases at different gestational (GA) and postnatal (PNA) ages.

MATERIALS AND METHODS

Ninety-four patients were evaluated. Immunohistochemical RHAMM expression was studied with digital image analysis, followed by hierarchical cluster analysis of both these data and clinical data to define subgroups. The air content of the lung was determined by computerized analysis. HA content was estimated by radiometric assay.

RESULTS

Cluster analysis defined six distinct patient groups (Group 1-2: 34-41 weeks GA; Group 3-5: 23-27 weeks GA; Group 6: mixed population). Group 1-5 showed individual patterns in RHAMM expression and HA content (Group 1: high RHAMM/low HA; Group 2: low RHAMM/low HA; Group 3: low RHAMM/low HA; Group 4: low RHAMM/high HA; Group 5: high RHAMM/high HA). HA content decreased with increasing PNA independently of GA. Negative correlation was observed between air content and RHAMM expression in the bronchiolar epithelium irrespective of clustered groups. Lung hypoplasia appeared in two distinctive groups, with significant differences in lung development and RHAMM expression.

CONCLUSIONS

RHAMM expression may show dynamic changes during pathological processes in the neonatal lung. The distribution of RHAMM in the lung tissue is heterogeneous with a predominance to the bronchiolar epithelium. We found a negative correlation between lung air content and RHAMM expression in bronchiolar epithelium.

Complete reversal of the clinical symptoms and image morphology of ketamine cystitis after intravesical hyaluronic acid instillation: A case report

RATIONALE

Ketamine abuse is an emerging issue in many countries, and ketamine cystitis (KC) is a growing disease which more and more urologists may encounter with. There was no gold standard diagnostic criteria of ketamine cystits established yet, but well-accepted with the positive substance abuse history and clinical symptoms. The clinical presentation of ketamine cystitis varies and may mimic those presented in interstitial cystitis (IC), such as voiding frequency, urgency with urge incontinence, dysuria, nocturia, burning sensation during urination, post urination pain, painful hematuria, and small bladder capacity, but there are still differences that KC presented with more urgency, hematuria, pyuria and upper urinary tract involvement such as ureteral stenosis, vesico-ureteric reflux, hydronephrosis and renal function impairment.

PATIENT CONCERNS

We presented an interesting case with a 36-year-old man who's symptoms mimic acute prostatitis but there was no positive pathogen been cultured. The computed tomography (CT) findings revealed asymmetrical bladder wall thickening, which misleading us to the impression of bladder cancer. After the cystoscopy with bladder biopsy, the pathology revealed severe inflammation without malignancy. After that, we prescribed anticholinergic agent, beta-3 agonist and nonsteroidal anti-inflammatory drug (NSAID) for him, but in vain.

DIAGNOSES

Erosive cystitis with prominent infiltration by eosinophils, lymphocytes, neutrophils and plasma cells.

INTERVENTIONS

Then we introduced hyaluronic acid (HA) instillation, once a week for total 10 times.

OUTCOMES

After the treatment, his urgency, frequency, nocturia improved and his bladder capacity increased from less than 100ml to 350mL per urination. The following magnetic resonance imaging (MRI) and bladder biopsy result revealed complete reversal.

LESSONS

To our literature review, this is the first case of ketamine cystitis presented with asymmetrical bladder wall thickening, which may be considered as an irreversible change, but turns out complete reversal of the clinical symptoms and image morphology after merely intravesical hyaluronic acid instillation.

Hyaluronic Acid in the Third Millennium

Since its first isolation in 1934, hyaluronic acid (HA) has been studied across a variety of research areas. This unbranched glycosaminoglycan consisting of repeating disaccharide units of N-acetyl-d-glucosamine and d-glucuronic acid is almost ubiquitous in humans and in other vertebrates. HA is involved in many key processes, including cell signaling, wound reparation, tissue regeneration, morphogenesis, matrix organization and pathobiology, and has unique physico-chemical properties, such as biocompatibility, biodegradability, mucoadhesivity, hygroscopicity and viscoelasticity. For these reasons, exogenous HA has been investigated as a drug delivery system and treatment in cancer, ophthalmology, arthrology, pneumology, rhinology, urology, aesthetic medicine and cosmetics. To improve and customize its properties and applications, HA can be subjected to chemical modifications: conjugation and crosslinking. The present review gives an overview regarding HA, describing its history, physico-chemical, structural and hydrodynamic properties and biology (occurrence, biosynthesis (by hyaluronan synthases), degradation (by hyaluronidases and oxidative stress), roles, mechanisms of action and receptors). Furthermore, both conventional and recently emerging methods developed for the industrial production of HA and its chemical derivatization are presented. Finally, the medical, pharmaceutical and cosmetic applications of HA and its derivatives are reviewed, reporting examples of HA-based products that currently are on the market or are undergoing further investigations.

Hyaluronic Acid and Periodontitis

Hyaluronic acid (HA; synonyms- Hyaluronan, Hyaluronate) is a glycosaminoglycan found in the connective tissue of vertebrates. It is the most abundant glycosaminoglycan of higher molecular weight in the extracellular matrix of soft periodontal tissues. The use of HA in the treatment of inflammatory process is established in medical areas such as orthopedics, dermatology and ophthalmology. In the field of dentistry, it has shown anti-inflammatory and anti-bacterial effects in gingivitis and periodontitis therapy. Due to its tissue healing properties, it could be used as an adjunct to mechanical therapy in the treatment of periodontitis.

A Clinical Evaluation of Efficacy and Safety of Hyaluronan Sponge with Vitamin C Versus Placebo for Scar Reduction

Background:

Scar formation after injury or surgery is a major clinical problem. Individually, hyaluronan, or hyaluronic acid (HA), and vitamin C have been shown to reduce scarring by means of different mechanisms. The authors evaluated the efficacy and safety of an HA sponge system containing an active derivative of vitamin C to determine whether the use of this product promotes healing and reduces inflammation and scarring after surgery.

Methods:

This double-blind, randomized, prospective study was approved by the local institutional review board. Participants who had unilateral or bilateral surgical scars more than 1 month but less than 18 months old were enrolled. Surgical scars were randomly assigned to receive placebo or HA sponge with vitamin C. Three blinded evaluators reviewed photographs of the incision lines and assessed the scars using a visual analog scale. A patient satisfaction survey was also administered. Participants were followed up at 4 weeks, 12 weeks, and 1 year.

Results:

Twenty-three patients were enrolled in the study. Six patients dropped out of the study, for a total of 17 patients included in final analysis. Mean (range) age of patient was 43.5 (25–67) years. Mean (range) body mass index was 27.4 (18–36.9) kg/m². The mean visual analog scale score for scars receiving HA sponge with vitamin C was slightly lower than the scars receiving placebo, but the difference was not statistically significant (t test; P = 0.9). The HA sponge with vitamin C was found to have significant positive findings on a patient satisfaction survey.

Conclusions:

The HA sponge system with vitamin C is safe to use in any scars older than 4 weeks. It has high patient satisfaction in achieving a better scar after surgery. The micro-roller used to apply the product was easy to use to potentially increase the spread of the medication in older scars.

Clinical Evaluation of Hyaluronic Acid Sponge with Zinc versus Placebo for Scar Reduction after Breast Surgery

BACKGROUND

Scar formation is a major source of dissatisfaction among patients and surgeons. Individually, hyaluronan, or hyaluronic acid (HA), and zinc have been shown to reduce scarring. The authors evaluated the safety and efficacy of an HA sponge with zinc compared with placebo when applied to bilateral breast surgery scars; specifically, they evaluated whether the use of this product modulates inflammation and immediate scarring in treated patients after bilateral breast surgery.

METHODS

This double-blind, randomized, prospective study was approved by the local institutional review board. Bilateral breast surgery patients with right and left incision lines were randomly assigned to receive HA sponge with zinc or placebo within 2 to 4 days after their procedure. Participants were followed up at 6 weeks, 12 weeks, and 1 year and evaluated at 12 weeks. Three blinded evaluators reviewed photographs of the incision lines and assessed the scars using a visual analog scale, new scale, and a patient satisfaction survey.

RESULTS

Nineteen bilateral breast surgery patients were enrolled in the study. Statistical analysis was performed on 14 patients who completed the follow-up. The mean visual analog scale score was lower for the side receiving the HA sponge with zinc (2.6) than for the side receiving placebo (3.0), indicating a better outcome (t test; P = 0.08). The HA sponge with zinc was found to have significant positive findings on a patient satisfaction survey (P = 0.01).

CONCLUSIONS

This is a preliminary study that shows zinc hyaluronan was associated with high patient satisfaction in achieving a better scar after bilateral breast surgery, irrespective of skin color. It seems to be safe and effective for early scars.

Adverse reaction after hyaluronan injection for minimally invasive papilla volume augmentation. A report on two cases

OBJECTIVES

To report two cases of adverse reaction after mucosal hyaluronan (HY) injection around implant-supported crowns, with the aim to augment the missing interdental papilla.

MATERIAL AND METHODS

Two patients with single, non-neighbouring, implants in the anterior maxilla, who were treated within the frames of a randomized controlled clinical trial testing the effectiveness of HY gel injection to reconstruct missing papilla volume at single implants, presented an adverse reaction. Injection of HY was performed bilaterally using a 3-step technique: (i) creation of a reservoir in the mucosa directly above the mucogingival junction, (ii) injection into the attached gingiva/mucosa below the missing papilla, and (iii) injection 2-3 mm apically to the papilla tip. The whole-injection session was repeated once after approximately 4 weeks.

RESULTS

Both patients presented with swelling and extreme tenderness with a burning sensation on the lip next to the injection area, after the second injection session. In one of the cases, a net-like skin discoloration (livedo reticularis) was also noted. The symptoms lasted for up to 7 days, and in both cases, symptoms resolved without any signs of skin or mucosal necrosis or any permanent damage.

CONCLUSION

Most likely, water attraction over time by the highly hygroscopic HY, exerted progressively an external vascular compression and at least partial occlusion of neighbouring blood vessels. An infection or an allergic reaction seems unlikely, since all symptoms gradually disappeared within a week irrespective use of antimicrobials, while an allergic reaction most likely would not have been restricted to one side.

Application of hyaluronic acid in the healing of non-experimental open wounds: A pilot study on 12 wounds in 10 client-owned dogs

Aim:

Veterinarians have frequently to deal with wounds to the skin, subcutis, and underlying muscle. The aim was to explore the application of hyaluronic acid (HA)-containing dressing on open skin wounds in dogs. The progress of healing was assessed by wound area reduction and two scoring scales applied in human medicine.

Materials and Methods:

Ten client-owned dogs with 12 cutaneous open wounds healed by the second intention were included. All wounds were treated using available in commerce HA-containing wound dressing from admission to complete re-epithelialization. At every clinical examination, wound area and scale scoring assessments were performed.

Results:

After debridement, an increased wound size was obtained while an improvement was determined by both grading systems. The median numbers of return to the clinic for bandage change were 5 times. The median time to complete wound healing was 34.5 days. The mean wound area at day 7, 14, 21, and 28 were, respectively, 90.4%, 47.7%, 22.4%, and 14.8% of the original size (for linear measurement) and 95.5%, 54.4%, 23.10%, and 14.8% of the original size (for software measurement). Regarding wound healing assessment tools, the agreement between two operators was considered high for both scales.

Conclusions:

HA-containing dressing may be a possible wound treatment for cutaneous open wounds in dogs. The assessment of wound quality using scale scoring system could be useful especially in the 1^st week and to direct clinical decision-making process.

Roles of Proteoglycans and Glycosaminoglycans in Wound Healing and Fibrosis

A wound is a type of injury that damages living tissues. In this review, we will be referring mainly to healing responses in the organs including skin and the lungs. Fibrosis is a process of dysregulated extracellular matrix (ECM) production that leads to a dense and functionally abnormal connective tissue compartment (dermis). In tissues such as the skin, the repair of the dermis after wounding requires not only the fibroblasts that produce the ECM molecules, but also the overlying epithelial layer (keratinocytes), the endothelial cells, and smooth muscle cells of the blood vessel and white blood cells such as neutrophils and macrophages, which together orchestrate the cytokine-mediated signaling and paracrine interactions that are required to regulate the proper extent and timing of the repair process. This review will focus on the importance of extracellular molecules in the microenvironment, primarily the proteoglycans and glycosaminoglycan hyaluronan, and their roles in wound healing. First, we will briefly summarize the physiological, cellular, and biochemical elements of wound healing, including the importance of cytokine cross-talk between cell types. Second, we will discuss the role of proteoglycans and hyaluronan in regulating these processes. Finally, approaches that utilize these concepts as potential therapies for fibrosis are discussed.

Hyaluronan in wound healing: rediscovering a major player

Wound healing involves a series of carefully modulated steps, from initial injury and blood clot to the final reconstituted tissue or scar. A dynamic reciprocity exists throughout between the wound, blood elements, extracellular matrix, and cells that participate in healing. Multiple cytokines and signal transduction pathways regulate these reactions. A major component throughout most of the process is hyaluronan, a straight-chain carbohydrate extracellular matrix polymer. Hyaluronan occurs in multiple forms, chain length being the only distinguishing characteristic between them. Levels of hyaluronan in its high-molecular-weight form are prominent in the earliest stages of wound repair. Progressively more fragmented forms occur in a manner not previously appreciated. We outline here steps in the wound healing cascade in which hyaluronan participates, as well as providing a review of its metabolism. Although described by necessity in a series of quantum steps, the healing process is constituted by a smooth continuum of overlapping reactions. The prevalence of hyaluronan in the wound (initially termed "hexosamine-containing mucopolysaccharide"), particularly in its early stages, was pointed out over half a century ago by the Harvard surgeon J. Engelbert Dunphy. It appears we are now returning to where we started.

Possible pathophysiology of ketamine-related cystitis and associated treatment strategies

Ketamine-related cystitis is characterized by ketamine-induced urinary frequency and bladder pain. It has become a serious problem in recent years. The most typical grossly pathological bladder change with ketamine related cystitis is a contracted bladder and bladder wall thickening. Ulcerative cystitis with an easily bleeding mucosa is a common cystoscopic finding. Microscopically, the urothelium is denuded and is infiltrated by inflammatory cells, such as mast cells and eosinophils. The pathogenesis of ketamine-related cystitis is complicated and involves many different pathways. Past evidence suggests a direct toxic effect, bladder barrier dysfunction, neurogenic inflammation, immunoglobulin-E-mediated inflammation, overexpression of carcinogenic genes, abnormal apoptosis and nitric oxide synthase-mediated inflammation contribute to the pathogenesis of ketamine-related cystitis. The first step to managing ketamine-related cystitis is always asking patients to cease ketamine. Medical treatment might be helpful in patients with early ketamine-related cystitis and abstinence from ketamine. Several case studies showed that the intravesical installation of hyaluronic acid and intravesical injection of botulinum toxin type A were effective for symptom relief in selected patients. For patients with irreversible pathological change, such as contracted bladder, augmentation enterocystoplasty might be the only solution to increase bladder capacity and relieve intractable bladder pain.

The use of hyaluronic acid based dressings to treat burns: A review

Deep cutaneous lesions such as burns, traumas or ulcers are all conditions characterized by a massive loss of dermis, bringing several important consequences. For the treatment of these conditions, the evolution of material science has made available new dressings based on natural and synthetic polymers. Hyaluronic acid (HA) is involved in many steps of the wound healing process, such as inflammation, granulation and re-epithelialization. In order to overcome the poor physical properties of the native polymer, such as solubility and rapid degradation, insoluble molecules starting from the natural compound were produced via esterification. Thanks to their improved structural properties, the dressings based on these hyaluronic acid derivatives represent a valuable option for the treatment of deep burns. This narrative monograph describes the development and the outcome of the use of these products in burns. The currently available clinical experience suggests that these HA medical devices represent a safe therapeutic method useful for the treatment of acute wounds.

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

PURPOSE

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

Myocardial extracellular matrix: an ever-changing and diverse entity

The cardiac extracellular matrix (ECM) is a complex architectural network consisting of structural and nonstructural proteins, creating strength and plasticity. The nonstructural compartment of the ECM houses a variety of proteins, which are vital for ECM plasticity, and can be divided into 3 major groups: glycoproteins, proteoglycans, and glycosaminoglycans. The common denominator for these groups is glycosylation, which refers to the decoration of proteins or lipids with sugars. This review will discuss the fundamental role of the matrix in cardiac development, homeostasis, and remodeling, from a glycobiology point of view. Glycoproteins (eg, thrombospondins, secreted protein acidic and rich in cysteine, tenascins), proteoglycans (eg, versican, syndecans, biglycan), and glycosaminoglycans (eg, hyaluronan, heparan sulfate) are upregulated on cardiac injury and regulate key processes in the remodeling myocardium such as inflammation, fibrosis, and angiogenesis. Albeit some parallels can be made regarding the processes these proteins are involved in, their specific functions are extremely diverse. In fact, under varying conditions, individual proteins can even have opposing functions, making spatiotemporal contribution of these proteins in the rearrangement of multifaceted ECM very hard to grasp. Alterations of protein characteristics by the addition of sugars may explain the immense, yet tightly regulated, variability of the remodeling cardiac matrix. Understanding the role of glycosylation in altering the ultimate function of glycoproteins, proteoglycans, and glycosaminoglycans in the myocardium may lead to the development of new biochemical structures or compounds with great therapeutic potential for patients with heart disease.

RCT to evaluate a hyaluronic acid containing gauze pad in leg ulcers of venous or mixed aetiology

OBJECTIVE

To investigate the efficacy and safety of an hyaluronic acid (HA)-impregnated gauze pad compared with a hydrocolloid (HC) dressing, in patients with leg ulcer of venous or mixed aetiology.

METHOD

A 56-day blind-observer, randomised, multicentre, controlled, non-inferiority trial. Patients were randomised to receive either an HA gauze pad (ialuset gauze pad) or an HC dressing (DuoDERM E).The primary endpoint was the difference between the groups regarding the percentages of patients achieving a reduction of at least 40% of the initial wound surface after 56 days of treatment (visit 5). Secondary endpoints included reduction of wound area, aspect of the wound (percentage of necrotic,fibrinous or granulation tissue), rate of complete ulcer healing, pain intensity, and clinical status of the peri-ulcerous skin.

RESULTS

In total, 170 patients were included and analysed in the intention-to-treat (ITT) population; 27 patients presented at least one major protocol deviation and were excluded from the per-protocol (PP) population.Therefore, 143 patients constituted the PP population (n=72 and n=71 in the HA gauze pad group and HC dressing group, respectively).At day 56, the confidence interval of the difference between the two groups for the percentage of patients with a reduction of at least 40% of the target ulcer initial surface was [-0.128; 0.164] with a lower limit above the non-inferiority threshold (-0.15). Peri-ulcerous skin was significantly less impaired in the HA gauze pad group for oedema at day 56 (p = 0.04), purpura at day 14 (p = 0.009) and for maceration at day 14 (p = 0.003). Other secondary endpoints were not significantly different between the two groups. Overall, both treatments were well tolerated and adverse events were comparable between the two groups regarding their pattern, frequency, likely relationship to treatment and severity which was mostly mild (grade I) or moderate (grade 2). These results were confirmed in the overall ITT population.

CONCLUSION

These data support the non-inferiority of the HA gauze pad compared with HC for the primary endpoint.The significant differences in favour of HA gauze pad regarding peri-ulcerous skin changes (oedema, purpura and maceration) may suggest a trend for HA gauze pad to have a better acceptability than the reference HC dressing.

DECLARATION OF INTEREST

This study was sponsored by Laboratoires Genévrier. Authors received honoraria for their contributions to the study, but have no other conflicts of interests to declare.

Effects of a cross-linked hyaluronic acid based gel on the healing of open wounds in dogs

OBJECTIVE

To compare effects of a cross-linked hyaluronic acid (HA) based gel (CMHA-S) to a standard wound management protocol on the healing of acute, full-thickness wounds in dogs.

STUDY DESIGN

A prospective, controlled, experimental study.

ANIMALS

Purpose-bred, adult, female beagles (n = 10).

METHODS

Two 2 × 2 cm wounds were surgically created bilaterally on the trunk of each dog and each side randomized to treatment (CMHA-S) or control (CON) groups. Total and open wound areas were measured with digital image planimetry at 15 time points. From these data, percent contraction and percent epithelialization were calculated. Tissue biopsies were obtained at 6 time points and histologic features were scored.

RESULTS

Total wound area was significantly larger and percent contraction was significantly less in CMHA-S compared to CON wounds at all data points between days 9 and 18. At day 25, and for the remainder of the study, CMHA-S wounds were smaller and contracted more than CON wounds, reaching significance at day 32. Percent epithelialization was significantly less in CMHA-S compared to CON wounds at all data points after day 11. Histologically, fibroblastic cellular infiltration was significantly higher in CMHA-S wounds at day 21.

CONCLUSIONS

CMHA-S wounds healed more slowly than CON wounds. This HA-based gel is not indicated in acute, full-thickness skin wounds in dogs as administered in this study. However, treatment may be beneficial in the mid-to-late repair stage of healing, or if scar minimization is desired. Further studies to evaluate the effects of the CMHA-S gel on canine wounds are indicated.

Efficacy and safety of hyaluronic acid in treatment of leg ulcers: a double-blind RCT

OBJECTIVE

To investigate the efficacy and safety of hyaluronic acid in the local treatment of leg ulcers of venous or mixed aetiology, compared with a neutral vehicle.

METHOD

A 60-day double-blind, randomised, multicentre, controlled superiority trial. The primary endpoint was the percentage wound size reduction after 45 days of treatment. Secondary endpoints included pain intensity, rate of complete ulcer healing, and aspect of the wound (percentage of necrotic, fibrinous or granulation tissue) and of the peri-ulcer skin.

RESULTS

A total of 101 patients were randomised and analysed in the intention-to-treat (ITT) population (50 in the hyaluronic acid; 51 in the control group). Seventy-five patients were considered in the per protocol (PP) population (38 vs 37, respectively). At day 45, the percentage of ulcer surface reduction was significantly greater in the hyaluronic acid treatment group (39 ± 6%) compared with the neutral vehicle (control) group (5 ± 9%) (p=0.002). A similar result was obtained at day 15, day 30 and day 60. From day 0 to day 45, pain intensity (VA S) decreased by mean 9.8 ± 3.5mm in the hyaluronic acid group, but slightly increased by 0.8 ± 3.2mm in the control group (p=0.029). Burden of pain, as estimated by the area under the curve of daily pain (from day 0 to day 60), was significantly lower in the hyaluronic acid group (121.9 ± 20.7mm2) than in the control group (207.4 ± 32.9mm2; p=0.028). Other secondary endpoints (rate of complete healing, characteristics of the wound and peri-ulcer skin) were not significantly different between the two groups. Treatments were well tolerated and adverse events were comparable between the two groups in terms of their frequency, relationship to treatment and severity.

CONCLUSION

Hyaluronic acid cream was significantly more effective than the neutral vehicle in the local treatment of leg ulcers of venous or mixed aetiology, in terms of wound size reduction and reducing the burden of pain, with a good safety profile.

Hyaluronan in intestinal homeostasis and inflammation: implications for fibrosis

The causes of fibrosis, or the inappropriate wound healing, that follows chronic intestinal inflammation are not well defined and likely involve the contributions of multiple cellular mechanisms. As other articles in this series confirm, inflammatory cytokines clearly play a role in driving cell differentiation to the myofibroblast phenotype, promoting proliferation and extracellular matrix deposition that are characteristic of fibrotic tissue. However, controlling the balance of cytokines produced and process of myofibroblast differentiation appears to be more complex. This review considers ways in which hyaluronan, an extracellular matrix component that is remodeled during the progression of colitis, may provide indirect as well as direct cues that influence the balancing act of intestinal wound healing.

Rheology of Sodium Hyaluronate Solutions and Relevance to their Use as Medical Implants

Hyaluronic acid is a high molecular weight, linear polysaccharide composed of repeating subunits of glucuronic acid and N-acetylglucosamine. The structure is shown in figure 1. In vertebrates, the polymer is widely distributed through all connective tissue and has been implicated in cell-cell interaction, cell matrix adhesion, cell mobility and extracellular matrix organization (1,2). NaHA is an important tissue lubricant (3,4) and has been shown to exert a facilitating influence on wound repair (5).

A Bilayer Hyaluronic Acid Wound Dressing to Promote Wound Healing in Diabetic Ulcer

Several spongy wound dressings composed of various hyaluronic acid (HA) materials were developed: HA aqueous solution with cross-linking agent (epoxy compound (HAWC), without cross-linking agent (HAWOC), and combined bilayer material HAWC and HAWOC (2LHA). The microstructure, sensitivity to hyaluronidase, sensitivity to free radicals, in vitro cytotoxicity, healing potential on full-thickness defect on and diabetic ulcers were evaluated. Scanning electron micrograph views of all HA wound dressings showed an interconnected channel and high porosity structure. HAWOC was degraded rapidly in hyaluronidase and free radical solution. The in vitro cytotoxicity of HAWC was significantly (p<0.05) higher than other HA wound dressings and reduced the released amount of VEGF from human fibroblast. The HAWOC remarkably facilitated the formation of vascularized granulation tissue and provided a HA enrichment wound healing process of either a full-thickness defect or a diabetic ulcer. In contrast, the presence of un-degradable products of HAWC seemed to interfere dermal tissue restoration. Nevertheless, because of the fragile properties, rapid degradation and wound adhesion of HAWOC, the 2LHA should be developed for diabetic ulcer therapy.

The use of sodium hyaluronate for the treatment of radiation recall dermatitis

Hyaluronic acid (HA) is a high-molecular weight polysaccharide, a glycosaminoglycan that enhances fibroblast movement and metabolism during wound healing, increasing collagen fibers forming granulation tissue. We describe a 42-year-old female, who developed radiation recall dermatitis following an allogeneic stem cell transplant from an unrelated donor (MUD-PBSCT). Her skin was treated with a topical sodium hyaluronate gel twice daily (RadiaplexRX, MPM Medical). There was marked improvement after 5 days of therapy without discontinuation of any of her therapeutic agents. At a time when the health care providers were faced with considerable treatment dilemmas, this patient demonstrated improvement in the symptoms of radiation recall dermatitis with the topical application of sodium hyaluronate and no change in her medication profile. This agent could successfully allow practitioners to treat radiation recall dermatitis without discontinuation of the recall trigger drug and thus jeopardizing the outcome of the treatment regimen. J Oncol Pharm Practice (2009) 15: 123—126.

Efficacy and tolerance of a hydrocolloid dressing containing hyaluronic acid for the treatment of leg ulcers of venous or mixed origin

OBJECTIVE

This study was aimed at comparing efficacy and tolerance of a new hydrocolloid dressing containing hyaluronic acid (HC + HA) to a reference hydrocolloid not containing hyaluronic acid (HC) in the treatment of leg ulcers of venous or mixed origin.

RESEARCH DESIGN AND METHODS

This was an open, prospective study, randomized in parallel groups, in which 125 patients were enrolled and treated for up to 42 days. The primary efficacy criterion was the reduction of the wound area; other efficacy criteria were the condition of the wound bed, and of the surrounding skin, and presence and severity of symptoms such as pain and itching.

RESULTS

After 42 days of treatment the median reduction of ulcer area was -42.6% (95% confidence interval [CI]: -66.6; -5.7) and -31.0% (95% CI: -51.6; -8.8) in the HC + HA group and in the reference HC group, respectively. The difference between treatments was not statistically significant. A reduction > or = 90% of the initial ulcer area was seen in 15 patients in the HC + HA dressing group and in only seven patients in the HC dressing group. Changes in wound bed condition in the two groups were not significantly different, except for a more marked reduction of fibrinous tissue in the HC + HA dressing group (p = 0.04), at Day 28. Both treatments were well tolerated.

CONCLUSIONS

The HC + HA dressing was equally well tolerated and with a trend to be more effective than the reference HC dressing in the treatment of leg ulcers of venous or mixed origin. Further research is needed to confirm these findings.

Hyalomatrix: a temporary epidermal barrier, hyaluronan delivery, and neodermis induction system for keratinocyte stem cell therapy

Keratinocyte stem cell technology provides at least an adjuvant therapy to clinically close large cutaneous wounds (e.g., burn wounds). Here, the performance of keratinocyte cultures depends primarily on the quality of the bed to which they are applied. Clinical take rates for cultured keratinocyte grafts are optimal when applied to a vascularized dermal bed with minimal bacterial colonization. In the absence of autologous dermis, staged reconstruction with a dermal equivalent or dermal regeneration template is required. A novel product, Hyalomatrix, is a bilayer of an esterified hyaluronan scaffold beneath a silicone membrane. The scaffold delivers hyaluronan to the wound bed, and the silicone membrane acts as a temporary epidermal barrier. The product has been investigated in a controlled, porcine, acute full-thickness excisional wound model. Cultured autologous keratinocytes (CAKs) were delivered on Laserskin to acute full-thickness wounds treated with Hyalomatrix within chambers, and graft take rates were assessed longitudinally using image analysis. In the absence of chambers, wound contraction was assessed. Clinical CAK take rates fall sequentially with delay in application post-Hyalomatrix pre-treatment, but repeated pre-treatment removed this, with maximal take of 57.2% at 5 weeks post-wounding. In the absence of chambers, more-complete wound closure resulted from edge re-epithelialization and contraction, by a factor of 5 at 1 month, and was achieved at least 2 weeks sooner in the gold standard controls of split-thickness autograft to an acute or pre-treated wound bed. Wound contraction and late neodermal morphology (1 year) were similar in pre-treated CAKs and split-thickness autograft wounds. In this model, the Hyalomatrix wound bed pre-treatment increase in CAK take appeared to be dose dependent. The product appeared to act as a hyaluronan delivery system rather than a dermal regeneration template. The silicone membrane may limit wound bed colonization, and the combination of this temporary barrier with hyaluronan delivery and neodermis induction has been termed a barrier-delivery-induction system. The development of similar systems for serial application offers an alternative to a dermal regeneration template when CAKs are engrafted in the hostile, colonized environment of large burn wounds.

Modeling the effects of treating diabetic wounds with engineered skin substitutes

In this paper, a novel mathematical model of wound healing in both normal and diabetic cases is presented, focusing upon the effects of adding two currently available commercial engineered skin substitute therapies to the wound (Apligraf) and Dermagraft). Our work extends a previously developed model, which considers inflammatory and repair macrophage dynamics in normal and diabetic wound healing. Here, we extend the model to include equations for platelet-derived growth factor concentration, fibroblast density, collagen density, and hyaluronan concentration. This enables us to examine the variation of these components in both normal and diabetic wound healing cases, and to model the treatment protocols of these therapies. Within the context of our model, we find that the key component to successful healing in diabetic wounds is hyaluronan and that the therapies work by increasing the amount of hyaluronan available in the wound environment. The time-to-healing results correlate with those observed in clinical trials and the model goes some way to establishing an understanding of why diabetic wounds do not heal, and how these treatments affect the diabetic wound environment to promote wound closure.

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

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

The effect of hyaluronic acid incorporation on fibroblast spreading and proliferation within PEG-diacrylate based semi-interpenetrating networks

The nanometer-scale mesh size of many synthetic crosslinked hydrogel networks restricts encapsulated cells to a rounded morphology that can inhibit cellular processes such as proliferation and migration that are essential for the early stages of remodeling and tissue formation. The objective of these studies was to investigate an approach for accelerating cellular remodeling based on the creation of semi-interpenetrating networks (IPNs) composed of hydrolytically degradable poly(ethylene glycol) (PEG) diacrylate macromers and native, enzymatically degradable extracellular matrix (ECM) components (collagen, gelatin and hyaluronic acid (HA)). Among the three ECM components investigated, addition of HA at concentrations of 0.12% w/v and greater supported fibroblast spreading throughout the three-dimensional network and significantly increased proliferation relative to control hydrogels without HA. Incorporation of HA resulted in relatively small changes in hydrogel physical/chemical properties such as swelling, degradation rate, and elastic modulus. Fibroblast spreading was eliminated by the addition of hyaluronidase inhibitors, demonstrating that cell-mediated enzymatic degradation of HA is a necessary mechanism responsible for the observed increases in fibroblast activity. By accelerating early cellular remodeling and growth, these semi-IPNs may be useful vehicles for cell transplantation in a variety of tissue engineering applications.

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

An evaluation of Hyalofill-F plus compression bandaging in the treatment of chronic venous ulcers

OBJECTIVE

Hyaluronan, a component of the extracellular matrix, plays a significant role in several aspects of tissue repair and the wound healing process.

METHOD

In this Italian study Hyalofill-F, a partial benzyl ester derivative of hyaluronan, used in combination with compression bandaging, was compared with the well-established therapy in Italy of non-adherent gauze plus compression therapy in the treatment of chronic venous leg ulcers.

RESULTS

Hyalofill-F plus compression bandaging performed significantly better than non-adherent gauze plus compression bandage in all of the clinically relevant efficacy parameters. Mean reduction in ulcer area in the hyaluronan-derivative group was 8.1 cm2 after eight weeks of treatment, compared with 0.4 cm2 in the comparator group. The resulting difference of 7.7 cm2 between the two groups was statistically significant (p = 0.0019). Furthermore, statistically significant results in favour of the hyaluronan-derivative group were obtained in the following: speed of epithelialisation; leveling of the margins; degree of maceration; pain intensity and frequency.

CONCLUSION

Hyalofill-F plus compression bandaging resulted in an earlier and greater decrease in ulcer area compared with non-adherent gauze plus compression bandaging, therapy supporting its use in the treatment of chronic venous ulcers.

Glycosaminoglycan Hydrogels as Supplemental Wound Dressings for Donor Sites

Chemically crosslinked glycosaminoglycan (GAG) hydrogel films were evaluated as biointeractive dressings in a porcine model for donor-site autograft wounds. Multiple 5 x 5 x 0.03 cm wounds were created on the dorsum of pigs. Half of the wounds were treated with a GAG film plus an occlusive dressing (Tegaderm), whereas the other half were treated with Tegaderm alone. At 3, 5, or 7 days after surgery, the partially healed wounds were excised and evaluated histologically for three animals at each time point. By day 3, epithelial cells had proliferated and migrated from wound edges and from epithelial islands associated with residual hair follicles to begin to cover the wound bed. A statistically significant increase in coverage was observed for GAG + Tegaderm-dressed wounds than for those with Tegaderm alone at day 3 and day 5 post-surgery. By day 7, all treatment groups were completely healed. Thus, GAG hydrogels accelerated wound healing by enhancing re-epithelialization.

A trial to assess the efficacy and tolerability of Hyalofill-F in non-healing venous leg ulcers

OBJECTIVE

This single-centre, open, uncontrolled pilot clinical trial set out to assess the efficacy and tolerability of Hyalofill-F (a partial benzyl ester derivative of hyaluronan), used in combination with compression bandaging, in the treatment of venous leg ulcers.

METHOD

The 20 patients enrolled into the study had venous insufficiency and a leg ulcer that had been refractory to treatment for one month. Treatment was continued for eight weeks, with weekly assessments.

RESULTS

During the study period four of the patients' ulcers healed completely. An average wound area reduction of 53.5% was seen in the ulcers that did not heal. Differences in ulcer area and ulcer depth between the initial and final visit were significant (p < 0.01, p = 0.03). The average healing rate (cm2/week reduction) was 1.26 +/- 1.7 (standard deviation). A calculated prognostic index was used to identify patients at high risk of a poor response to compression therapy (10% probability of wound closure at 120 weeks). These patients demonstrated a mean 63% decrease in wound area after eight weeks of treatment with Hyalofill-F plus compression bandaging. All wounds showed a positive response in terms of granulation-tissue formation. The comfort of the dressing was described as excellent.

CONCLUSION

The hyaluronan derivative showed promising results in initiating the healing process in chronic venous ulcers. It was found to be well tolerated and safe to use. However, further clinical trials should be performed involving a control group to verify these data.

DECLARATION OF INTEREST

This study was sponsored by Fidia Advanced Biopolymers, Italy.

Pathophysiology of intra-abdominal adhesion and abscess formation, and the effect of hyaluronan

BACKGROUND

Intra-abdominal adhesions and abscesses cause significant morbidity and mortality. The formation of fibrin in the abdominal cavity is a common pathophysiological pathway for both. The aim of this review was to investigate the pathophysiology of intra-abdominal adhesions and abscesses, and to explore the possible sites of action of hyaluronan.

METHODS

Data were reviewed from the literature using the Medline database.

RESULTS

Both surgery and peritonitis disturb the equilibrium between coagulation and fibrinolysis in the abdominal cavity in favour of the coagulation system. Hyaluronan-based agents reduce adhesion formation after surgery. Moreover, hyaluronan solution reduces abscess formation in experimental peritonitis. Possible mechanisms of action include mechanical separation of wound surfaces, improvement of peritoneal healing, modulation of the inflammatory response and enhanced fibrinolysis.

CONCLUSION

Diminished fibrin degradation is a common pathway for the formation of adhesions and abscesses. The potential of hyaluronan-based agents to reduce intra-abdominal adhesions and abscesses in abdominal surgery and sepsis is a promising new concept. Elucidating the mechanisms involved and the clinical application of hyaluronan in peritonitis are challenges for future research.

Outcomes of hyaluronan therapy in diabetic foot wounds

The purpose of this study was to evaluate outcomes of persons with neuropathic diabetic foot wounds treated with a hyaluronan-containing dressing. Data were abstracted for 36 patients with diabetes, 72.2% male, aged 60.0+/-10.7 years and a mean glycated hemoglobin (HbA(1c)) of 9.5+/-2.5% presenting for care at two large, multidisciplinary wound care centers. All patients received surgical debridement for their diabetic foot wounds and were placed on therapy consisting of hyaluronan dressing (Hyalofill, Convatec, USA) with dressing changes taking place every other day. Outcomes evaluated included time to complete wound closure and proportion of patients achieving wound closure in 20 weeks. Hyalofill therapy was used until the wound bed achieved 100% granulation tissue. Therapy was then followed by a moisture-retentive dressing until complete epithelialization. In total, 75.0% of wounds measuring a mean 2.2+/-2.2 cm(2) healed in the 20-week evaluation period. Of those that healed in this period, healing took place in a mean 10.0+/-4.8 weeks. The average duration of Hyalofill therapy in all patients was 8.6+/-4.2 weeks. Deeper (UT Grade 2A) wounds were over 15 times less likely to heal than superficial (1A) wounds (94.7 vs. 52.9%, Odds Ratio=15.9, 95% Confidence Interval=1.7-142.8, P=0.006). We conclude that a regimen consisting of moist wound healing using hyaluronan-containing dressings may be a useful adjunct to appropriate diabetic foot ulcer care. We await the completion of a multicenter randomized controlled trial in this area to either support or refute this initial assessment.

Growth factors in the treatment of diabetic foot ulcers

BACKGROUND

Chronic foot ulceration is a major source of morbidity in diabetic patients. Despite traditional comprehensive wound management, including vascular reconstruction, there remains a cohort of patients with non-responding wounds, often resulting in amputation. These wounds may benefit from molecular manipulation of growth factors to enhance the microcirculation.

METHODS

A review of the current literature was performed using Pubmed, with secondary references obtained from key articles.

RESULTS AND CONCLUSION

There has been a generally disappointing clinical outcome from growth factor trials, although topical platelet-derived growth factor has shown significant benefit and should be considered in non-healing, well perfused ulcers after failure of conventional wound care. The modulatory role of the extracellular matrix in the cellular response to growth factors and data from regenerative-type fetal wound healing are further areas of interest. The chemical induction of microvessel formation may become a future therapeutic option.

Extensive traumatic soft tissue loss: reconstruction in severely injured patients using cultured hyaluronan-based three-dimensional dermal and epidermal autografts

BACKGROUND

This report demonstrates the potential of two-stage autologous keratodermal grafting as a starting point for noninvasive reconstruction of extensive traumatic soft tissue defects.

METHODS

In three severely injured patients, skin biopsies for cell cultivation were taken. Cultured "neodermis" consisting of cultured autologous fibroblasts grown on biocompatible three-dimensional scaffolds made up of benzyl ester of hyaluronan was grafted on conditioned defect areas. After ingrowth of dermal substitutes, transplantation of cultured autologous keratinocytes on hyaluronan-based laser-perforated membranes was performed. Ten days later, a 0.2-mm thin, 1:6 meshed autograft was overlaid. Clinical follow-up, histologic, and immunohistochemical findings were documented.

RESULTS

Grafting with cultured autologous fibroblasts revealed a suitable dermal tissue replacement. Epithelialization was evident after transplantation of keratinocytes. Final closure of the defects with "normoelastic" tissue properties was achieved after thin mesh-grafting.

CONCLUSION

Preliminary findings with the described method seem to be very promising. As in all fields of tissue engineering, long-term studies and further follow-up are required.

Hyaluronic acid in incision wound fluid: a clinical study with the Cellstick device in children

When inserted into a human incision wound, the Cellstick device harvests inflammatory cells and collects wound fluid, reflecting time-related changes in cell populations and in wound fluid composition. Hyaluronic acid has been postulated to be an important factor in scar reduction in wound healing and in scarless fetal wound healing. The aim of this work was to determine the concentration and variation of hyaluronic acid and proportions of wound cells in closed surgical wounds in children at two time points. The Cellstick device was inserted subcutaneously into the wound at the end of an elective inguinal hernia operation on 37 healthy boys, and the devices were removed 3+/-1 or 24+/-3 hours after surgery. Haluronic acid concentration was measured from the wound fluid and a differential count of the wound cells was performed. There was a significant decrease in hyaluronic acid concentration from 3+/-1 to 24+/-3 hours after surgery (p<0.001, Kruskal-Wallis anova). The variance of hyaluronic acid concentration in wound fluid differed between the wounds at the two time points (p<0.01, Levene test for homogeneity of variance). A positive correlation between hyaluronic acid concentration and patient age (r=0.91, p<0.05, Spearman) at 3+/-1 hours post surgery and between HA and wound lymphocytes (r=0.38, p<0.05, Spearman) was also found. We conclude that the hyaluronic acid concentration in wound fluid peaks early in children and decreases significantly by 3 to 24 hours after surgery, and the concentrations in the wound fluid of healthy boys are more variable 3 hours than at 24 hours after surgery.

Treatment of recalcitrant ulcers in pyoderma gangrenosum with mycophenolate mofetil and autologous keratinocyte transplantation on a hyaluronic acid matrix

Pyoderma gangrenosum sometimes takes a recalcitrant course that is unresponsive to standard immuno-suppression with corticosteroids and/or cyclosporin A. In these cases improvement of painful ulcerations is a therapeutic challenge. We report a 17-year-old boy with severe pyoderma gangrenosum treated successfully with mycophenolate mofetil and autologous keratinocyte transplantation using an esterified hyluronic acid delivery system.

Dialysis solution containing hyaluronan: effect on peritoneal permeability and inflammation in rats

BACKGROUND

Hyaluronan (HA), a high molecular weight mucopolysaccharide found in interstitial tissues and fluid, is lost from the peritoneal cavity during peritoneal dialysis. In order to determine the role of HA in peritoneal function, we investigated the effects of exogenous HA on peritoneal permeability, markers of intraperitoneal inflammation, and peritoneal morphology in rats exposed to peritoneal dialysis solution for four weeks.

METHODS

Wistar rats were infused intraperitoneally, twice daily, with conventional, hypertonic dialysis solution (Dianeal 3.86%; control) or Dianeal solution containing 10 mg/dL of high molecular weight HA. Peritoneal permeabilities and clearances of solutes and protein were determined using a modified peritoneal permeability test (peritoneal equilibration test) at the beginning and the end of the treatment. Peritoneal volume and ultrafiltration were determined using a macromolecular marker and by gravimetric methods. Peritoneal inflammation was determined by cell counts and differential and by the measurement of cytokine concentrations in the dialysate effluent. Peritoneal thickness and HA content were determined in liver and mesentery biopsies taken at the end of the experiment.

RESULTS

After four weeks of exposure to the dialysis solution, transperitoneal protein equilibration was significantly lower in HA-treated rats compared with rats treated with Dianeal alone (46% lower for albumin, P < 0.003; 33% lower for total protein, P < 0.001). The total drained volume after a four hour dwell was 29% higher in the HA group compared with the control (P < 0.001), yielding a positive net ultrafiltration in the HA group versus a negative net ultrafiltration in controls. Peritoneal clearances of urea and creatinine tended to be elevated in HA-treated rats, while clearances of total protein and albumin tended to be lower. Dialysate effluent from rats exposed to HA contained a lower percentage of neutrophils (8.8 +/- 22.8 +/- 9.5%, P < 0.01) and lower levels of the cytokines, tumor necrosis factor-alpha (11.2 +/- 14.7 vs. 42.3 +/- 35.3 pg/mL, P < 0.05) and monocyte chemoattractant protein-1 MCP-1 (72.0 +/- 86.5 vs. 402.4 +/- 258.3 pg/mL, P < 0.02), compared with rats treated with Dianeal alone. The thickness of the peritoneal interstitium showed a similar increase in both groups, but mesenteric tissue from the HA group contained more HA (48%, P < 0.01) than tissue from control animals.

CONCLUSIONS

The addition of HA to peritoneal dialysis solution decreases protein permeability, increases ultrafiltration, and decreases cytokine levels and the proportion of peritoneal neutrophils in dialysate from rats exposed to hypertonic dialysis solution. These results suggest that exogenous HA may help to protect the peritoneal membrane during exposure to dialysis solutions. These benefits, if sustained in the clinical setting, could lead to improvements in the therapy of peritoneal dialysis.

Autologous keratinocytes cultured on benzylester hyaluronic acid membranes in the treatment of chronic full-thickness ulcers

Keratinocytes were obtained from three patients with chronic full-thickness ulcers of different aetiologies. The cells were isolated, cultured and then seeded on to a membrane composed of benzylester hyaluronic acid. Once the keratinocytes had become subconfluent, the keratinocyte-containing matrix sheets were then applied as autologous grafts to the patients' ulcers. Results indicate that autologous grafting of keratinocytes cultured on benzylester hyaluronic acid membranes provides improved graft handling, reduces total time required for tissue cultivation and enhances cellular vitality because of the possibility of grafting at a subconfluent non-differentiated stage.

Effects of hyaluronan on periosteal grafts for large full-thickness defects in rabbit articular cartilage

We studied the effects of hyaluronan (HA) on chondrogenesis in periosteal grafts in rabbit knees to elucidate the effects of this agent in the repair of articular cartilage. Large full-thickness defects of the articular cartilage were created in the anteromedial part of the femoral articular surface of bilateral knee joints. Periosteal grafts were then harvested and sutured onto the defects. HA was injected in the right knee immediately after the operation and then once a week for 4 weeks (HA group). The same volume of saline was injected in the left knee in the control group. The animals were killed 2, 5, 8, and 12 weeks after the operation. Macroscopic and histological findings of the regenerated tissue were evaluated with a semiquantitative histological grading system. The total histological scores of the HA group were better than those in the control group at each time examination point. At 12 weeks, in particular, the scores for surface regularity and integration to adjacent articular cartilage were significantly better in the HA group than in the control group (P < 0.05). No significant differences were observed between the two groups in regard to the area healed (%). HA may have beneficial effects on the repair of large full-thickness defects of the articular cartilage with autologous periosteal grafts.