Structural variations in a single hyaluronan derivative significantly alter wound-healing effects in the rabbit maxillary sinus

Randomized Clinical Trial to Evaluate the Efficacy and Tolerability of Nebulized Hyaluronic Acid and Xylitol Based Solution after Septoturbinoplasty

Septoplasty and turbinate surgery are among the most frequent surgical procedures to improve nasal obstruction and quality of life. These procedures usually imply the presence of congestion, secretions, and crusting related to the movement of the instruments during surgery. However, the use of nasal lavage may reduce this situation. The addition of Hyaluronic acid or Xylitol offers advantages in these washes. This study was a randomized, double-blind, controlled trial. All patients underwent endoscopic septoplasty with inferior turbinate submucosal resection without posterior nasal packing. SNOT-22, main VAS, NOSE, Modified Lund-Kennedy endoscopic scale, number of crusts and adhesions were quantified before and on the day of the surgery, visit three (seven days), visit four (fourteen days), and visit five (twenty-eight days). Forty-seven patients completed the study, divided into a standard saline arm (group 1, 22 patients) and normal saline plus HA and Xylitol arm (group 2, 27 patients). Both treatment groups improved their quality of life and objective parameters during the four weeks of the study. All patients tolerated the nasal irrigations well, and none discontinued the treatments. The study concludes that nasal washes of Aluneb Isotónico^® offer several benefits to patients as a protective and preventative agent.

International consensus statement on allergy and rhinology: rhinosinusitis 2021

I.

EXECUTIVE SUMMARY

BACKGROUND: The 5 years since the publication of the first International Consensus Statement on Allergy and Rhinology: Rhinosinusitis (ICAR-RS) has witnessed foundational progress in our understanding and treatment of rhinologic disease. These advances are reflected within the more than 40 new topics covered within the ICAR-RS-2021 as well as updates to the original 140 topics. This executive summary consolidates the evidence-based findings of the document.

METHODS

ICAR-RS presents over 180 topics in the forms of evidence-based reviews with recommendations (EBRRs), evidence-based reviews, and literature reviews. The highest grade structured recommendations of the EBRR sections are summarized in this executive summary.

RESULTS

ICAR-RS-2021 covers 22 topics regarding the medical management of RS, which are grade A/B and are presented in the executive summary. Additionally, 4 topics regarding the surgical management of RS are grade A/B and are presented in the executive summary. Finally, a comprehensive evidence-based management algorithm is provided.

CONCLUSION

This ICAR-RS-2021 executive summary provides a compilation of the evidence-based recommendations for medical and surgical treatment of the most common forms of RS.

Functional DNA-based hydrogel intelligent materials for biomedical applications

Multifunctional intelligent DNA hydrogels have been reviewed for many biomedical applications.

Thiolated Hyaluronic Acid as Versatile Mucoadhesive Polymer: From the Chemistry Behind to Product Developments-What Are the Capabilities?

Within the last decade, intensive research work has been conducted on thiolated hyaluronic acids (HA-SH). By attaching sulfhydryl ligands onto naturally occurring hyaluronic acid various types of HA-SH can be designed. Due the ability of disulfide bond formation within the polymer itself as well as with biological materials, certain properties such as mucoadhesive, gelling, enzyme inhibitory, permeation enhancing and release controlling properties are improved. Besides the application in the field of drug delivery, HA-SH has been investigated as auxiliary material for wound healing. Within this review, the characteristics of novel drug delivery systems based on HA-SH are summarized and the versatility of this polymer for further applications is described by introducing numerous relevant studies in this field.

Effect of a combination of mometasone furoate, levofloxacin, and retinyl palmitate with an in situ gel-forming nasal delivery system on nasal mucosa damage repair in an experimental rabbit model

BACKGROUND

In this study a combination of Mometasone Furoate (MF)+Levofloxacin hemihydrate (LH)+Retinyl palmitate (RP) with an in situ gel-forming delivery system was evaluated at different stages of nasal mucosal damage repair in a rabbit maxillary sinus model.

METHODS

In this study, 28 rabbits were included and assigned randomly to four groups. In all rabbits, a standard ostium was opened in the medial wall of the maxillary sinus by using a drill. Two different subsequently prepared gels with an in situ gel-forming delivery system were used. Of these 14 nasal cavities, combination 1 (active combination) was applied daily to 5, combination 2 (placebo) to 5, while 4 did not receive any pharmaceutical treatment. The diameter of the ostium was measured. Histopathological assessment was performed.

RESULTS

After 2, 3 and 4 weeks, the ostium diameter was significantly wider in the group where gel 1 had been applied compared to both the placebo group and control group. In the group treated with gel 1, after 2, 3 and 4 weeks the presence of superficial cilia was significantly greater, surface epithelium significantly less. In the 4th week, histologic scores for fibroblastic proliferation and vascular proliferation in the group treated with gel 1 were better than in either the control group or the placebo group. With gel 1, chronic inflammation parameters were also significantly lower than in the other groups.

CONCLUSION

The MF+LH+RP mixture with an in situ gel-forming nasal delivery system applied for wound healing after FESS prevents the formation of stenosis and is favorable for proper 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.

Self-cross-linked hyaluronic acid hydrogel in ethmoidectomy: a randomized, controlled trial

BACKGROUND

This study was designed to evaluate the safety and efficacy of a novel, self-cross-linked hyaluronic acid (HA) hydrogel compared with carboxymethylcellulose (CMC) viscous foam in promoting healing when applied after ethmoidectomy. A prospective, randomized, controlled, blinded clinical trial was performed. The study was performed by four surgeons operating in two community hospitals.

METHODS

Thirty patients with bilateral chronic rhinosinusitis underwent bilateral total ethmoidectomy. Intraoperatively, each patient received 5 mL of HA hydrogel in one ethmoid cavity and 5 mL of CMC contralaterally. The material applied within each ethmoid cavity was randomly assigned before surgery. An independent surgeon, blinded to the material used to treat each ethmoid cavity, evaluated postoperative endoscopic video at 1 and 2 weeks for edema, crusting, and mucopurulence and at 6 and 12 weeks for remucosalization and scarring/synechiae. Twenty-item Sino-Nasal Outcome Test SNOT-20 data were collected at each visit. A small sample underwent endoscopic mucosal biopsy.

RESULTS

Twenty-nine of 30 patients completed the protocol. The difference in edema, crusting, and mucopurulence at 1 and 2 weeks was not statistically significant; however, at 6 and 12 weeks, the HA hydrogel showed statistically significant reduction in both overall endoscopic grade (p < 0.05), as well as synechiae formation (p < 0.05), with a trend toward superiority in remucosalization (p = 0.08). Histological analysis of six subjects at 12 weeks showed a nonsignificant trend toward a greater amount of regenerated cilia present with the HA hydrogel (p = 0.23). SNOT-20 scores declined 78.8% from preoperative scores.

CONCLUSION

Self-cross-linked HA hydrogel provides superior wound healing to CMC after ethmoidectomy.

Effects of cryotherapy on the maxillary antrostomy patency in a rabbit model of chronic rhinosinusitis

It is acknowledged that many causes of failures in endoscopic sinus surgery are related to scarring and narrowing of the maxillary antrostomy. We assessed the effect of low-pressure spray cryotherapy in preventing the maxillary antrostomy stenosis in a chronic rhinosinusitis (CRS) rabbit model. A controlled, randomized, double-blind study was conducted on 22 New Zealand rabbits. After inducing unilateral rhinogenic CRS, a maxillary antrostomy was performed and spray cryotherapy was employed on randomly selected 12 rabbits, while saline solution was applied to the control group (n = 10). The antrostomy dimensions and the histological scores were assessed 4 weeks postoperatively. The diameter of cryotreated antrostomy was significantly larger at 4 weeks than that in the control group. At 4 weeks, the maxillary antrostomy area in the study group was significantly larger than the mean area in the control group (103.92 ± 30.39 mm² versus 61.62 ± 28.35 mm², P = 0.002). Submucosal fibrous tissues and leukocytic infiltration in saline-treated ostia were more prominent than those in cryotreated ostia with no significant differences between the two groups regarding the histological scores. Intraoperative low-pressure spray cryotherapy increases the patency of the maxillary antrostomy at 4 weeks postoperatively with no important local side effects.

The clinical outcomes of new hyaluronan nasal dressing: a prospective, randomized, controlled study

BACKGROUND

Poor postoperative wound healing after endoscopic sinus surgery (ESS) remains a significant problem. This study evaluates the efficacy and safety of a new absorbable hyaluronan hydrogel.

METHODS

A prospective, randomized, controlled trial was conducted. Fifty-five patients with bilateral ESS were recruited and randomized to receive absorbable hyaluronan hydrogel in one side as treated and the opposite side without absorbable hyaluronan hydrogel as control. Clinical outcome measures were assessed at postoperative 1, 2, 4, 8, and 12 weeks.

RESULTS

Fifty-four patients completed the study. Overall, absorbable hyaluronan hydrogel significantly promotes the reepithelization process and reduces the presence of obstructing synechia, nonobstructing synechia, edema, crust, and mild mucopurulent drainage (all p ≤ 0.0002). At all postoperative follow-up visits, the promotion in reepithelization is statistically significant at 2, 4, and 8 weeks, and the reductions in the presence of nonobstructing synechia, edema, crust, and mild mucopurulent drainage are all statistically significant except for the presence of crust at 12 weeks and mild mucopurulent drainage at 1 and 12 weeks. Although the presence of obstructing synechia at each follow-up visit between groups does not reach statistical significance, the incidence ranges from 5.56 to 12.96% in the control group and from 0 to 3.70% in the treated group. No adverse event related to treatment was observed.

CONCLUSION

In this clinical study, data analyses suggest that this new absorbable hyaluronan hydrogel, as nasal dressing/packing after ESS is safe and promotes the postoperative reepithelization process and reduces the presence of synechia, edema, crust, and mild mucopurulent drainage.

The evaluation of two new hyaluronan hydrogels as nasal dressing in the rabbit maxillary sinus

BACKGROUND

The postoperative scaring, ostial stenosis, and adhesions after functional endoscopic sinus surgery for chronic rhinosinusitis remains a major problem. This study was designed to evaluate two new hyaluronan (HA) hydrogels for neo-ostium antistenosis and promoting wound healing in a rabbit maxillary sinus model.

METHODS

The anterior wall of the maxillary sinus of 48 rabbits was removed to create a 4-mm circumferential wound both on the nasal and on the sinus sides. A rapid-gelling HA hydrogel or preformed HA hydrogel was filled randomly into the right or left sinus, while the opposite sinus served as blank control or was treated with Merogel (Medtronic Xomed Surgical Products, Jacksonville, FL) as control. The neo-ostium diameter and histological scores were evaluated and analyzed postoperatively.

RESULTS

The neo-ostium diameter in the rapid-gelling HA hydrogel-treated side was significantly larger than that in the blank control side with a mean difference of 1.46 ± 0.99 mm (p = 0.03), 1.30 ± 0.61 mm (p = 0.0087), and 1.60 ± 0.25 mm (p = 0.00015) at 2, 3, and 4 weeks, respectively; the neo-ostium diameter in the preformed HA hydrogel-treated side at 2 weeks was significantly larger than that in the blank control side or Merogel control side with a mean difference of 1.46 ± 0.76 mm (p = 0.002) or 0.54 ± 0.36 mm (p = 0.007), respectively. The preformed HA hydrogel-treated side showed better histology scores at 2 weeks in heterophils, fibrosis, and osteogenesis than the blank control, and the chronic inflammation (lymphocyte/plasmacyte infiltration) was not prevalent.

CONCLUSION

During the postoperative follow-up period both of the two HA hydrogels significantly prevented neo-ostium stenosis and the preformed HA hydrogel promoted wound healing.

Nasal packing and stenting

Nasal packs are indispensable in ENT practice. This study reviews current indications, effectiveness and risks of nasal packs and stents. In endoscopic surgery, nasal packs should always have smooth surfaces to minimize mucosal damage, improve wound healing and increase patient comfort. Functional endoscopic endonasal sinus surgery allows the use of modern nasal packs, since pressure is no longer required. So called hemostatic/resorbable materials are a first step in this direction. However, they may lead to adhesions and foreign body reactions in mucosal membranes. Simple occlusion is an effective method for creating a moist milieu for improved wound healing and avoiding dryness. Stenting of the frontal sinus is recommended if surgery fails to produce a wide, physiologically shaped drainage path that is sufficiently covered by intact tissue.

The generation of 3-D tissue models based on hyaluronan hydrogel-coated microcarriers within a rotating wall vessel bioreactor

With the increasing necessity for functional tissue- and organ equivalents in the clinic, the optimization of techniques for the in vitro generation of organotypic structures that closely resemble the native tissue is of paramount importance. The engineering of a variety of highly differentiated tissues has been achieved using the rotating wall vessel (RWV) bioreactor technology, which is an optimized suspension culture allowing cells to grow in three-dimensions (3-D). However, certain cell types require the use of scaffolds, such as collagen-coated microcarrier beads, for optimal growth and differentiation in the RWV. Removal of the 3-D structures from the microcarriers involves enzymatic treatment, which disrupts the delicate 3-D architecture and makes it inapplicable for potential implantation. Therefore, we designed a microcarrier bead coated with a synthetic extracellular matrix (ECM) composed of a disulfide-crosslinked hyaluronan and gelatin hydrogel for 3-D tissue engineering, that allows for enzyme-free cell detachment under mild reductive conditions (i.e. by a thiol-disulfide exchange reaction). The ECM-coated beads (ECB) served as scaffold to culture human intestinal epithelial cells (Int-407) in the RWV, which formed viable multi-layered cell aggregates and expressed epithelial differentiation markers. The cell aggregates remained viable following dissociation from the microcarriers, and could be returned to the RWV bioreactor for further culturing into bead-free tissue assemblies. The developed ECBs thus offer the potential to generate scaffold-free 3-D tissue assemblies, which could further be explored for tissue replacement and remodeling.

Use of hyaluronan-derived hydrogels for three-dimensional cell culture and tumor xenografts

The practice of in vitro three-dimensional (3-D) cell culture has lagged behind the realization that classical two-dimensional (2-D) culture on plastic surfaces fails to mirror normal cell biology. Biologically, a complex network of proteins and proteoglycans that constitute the extracellular matrix (ECM) surrounds every cell. To recapitulate the normal cellular behavior, scaffolds (ECM analogs) that reconstitute the essential biological cues are required. This unit describes the 3-D cell culture and tumor engineering applications of Extracel, a novel semisynthetic ECM (sECM), based on cross-linked derivatives of hyaluronan and gelatin. A simplified cell encapsulation and pseudo-3-D culturing (on top of hydrogels) protocol is provided. In addition, the use of this sECM as a vehicle to obtain tumor xenografts with improved take rates and tumor growth is presented. These engineered tumors can be used to evaluate anticancer therapies under physiologically relevant conditions.

Modular extracellular matrices: solutions for the puzzle

The common technique of growing cells in two-dimensions (2-D) is gradually being replaced by culturing cells on matrices with more appropriate composition and stiffness, or by encapsulation of cells in three-dimensions (3-D). The universal acceptance of the new 3-D paradigm has been constrained by the absence of a commercially available, biocompatible material that offers ease of use, experimental flexibility, and a seamless transition from in vitro to in vivo applications. The challenge-the puzzle that needs a solution-is to replicate the complexity of the native extracellular matrix (ECM) environment with the minimum number of components necessary to allow cells to rebuild and replicate a given tissue. For use in drug discovery, toxicology, cell banking, and ultimately in reparative medicine, the ideal matrix would therefore need to be highly reproducible, manufacturable, approvable, and affordable. Herein we describe the development of a set of modular components that can be assembled into biomimetic materials that meet these requirements. These semi-synthetic ECMs, or sECMs, are based on hyaluronan derivatives that form covalently crosslinked, biodegradable hydrogels suitable for 3-D culture of primary and stem cells in vitro, and for tissue formation in vivo. The sECMs can be engineered to provide appropriate biological cues needed to recapitulate the complexity of a given ECM environment. Specific applications for different sECM compositions include stem cell expansion with control of differentiation, scar-free wound healing, growth factor delivery, cell delivery for osteochondral defect and liver repair, and development of vascularized tumor xenografts for personalized chemotherapy.

Prevention of peritendinous adhesions using a hyaluronan-derived hydrogel film following partial-thickness flexor tendon injury

Peritendinous adhesions are an important complication of flexor tendon injury. Three hyaluronan (HA)-derived biomaterials were evaluated for the reduction of peritendinous adhesions following partial-thickness tendon injury in rabbits. Rabbits (n = 24) were divided into three groups (n = 8 per group), which were used for gross evaluation, histologic assessment, or biomechanical testing. The fourth and third toes from both hindpaws of each rabbit were randomly assigned to one of four treatments: (i) untreated control, (ii) Seprafilm, (iii) Carbylan-SX in situ crosslinked hydrogel, and (iv) preformed Carbylan-SX film. Rabbits were sacrificed at 3 weeks postsurgery and evaluated anatomically, histologically, and mechanically. All materials used reduced adhesions relative to untreated controls for all three evaluations. Both the gross anatomic and histologic results revealed that Carbylan-SX film was statistically superior to Seprafilm and Carbylan-SX gel in preventing tendon adhesion formation. In biomechanical tests, the Carbylan-SX film-treated hindpaws required the least force to pull the tendon from the sheath. This force was statistically indistinguishable from that required to extrude an unoperated tendon (n = 8). Carbylan-SX gel was less effective than Carbylan-SX film but superior to Seprafilm for all evaluations. A crosslinked HA-derived film promoted healing of a flexor tendon injury without the formation of fibrosis at 3 weeks postoperatively.

Engineering a clinically-useful matrix for cell therapy

The design criteria for matrices for encapsulation of cells for cell therapy include chemical, biological, engineering, marketing, regulatory, and financial constraints. What is required is a biocompatible material for culture of cells in three-dimensions (3-D) that offers ease of use, experimental flexibility to alter composition and compliance, and a composition that would permit a seamless transition from in vitro to in vivo use. The challenge is to replicate the complexity of the native extracellular matrix (ECM) environment with the minimum number of components necessary to allow cells to rebuild a given tissue. Our approach is to deconstruct the ECM to a few modular components that can be reassembled into biomimetic materials that meet these criteria. These semi-synthetic ECMs (sECMs) employ thiol-modified derivatives of hyaluronic acid (HA) that can form covalently crosslinked, biodegradable hydrogels. These sECMs are "living" biopolymers, meaning that they can be crosslinked in the presence of cells or tissues to enable cell therapy and tissue engineering. Moreover, the sECMs allow inclusion of the appropriate biological cues needed to simulate the complexity of the ECM of a given tissue. Taken together, the sECM technology offers a manufacturable, highly reproducible, flexible, FDA-approvable, and affordable vehicle for cell expansion and differentiation in 3-D.

Evaluating drug efficacy and toxicology in three dimensions: using synthetic extracellular matrices in drug discovery

The acceptance of the new paradigm of 3-D cell culture is currently constrained by the lack of a biocompatible material in the marketplace that offers ease of use, experimental flexibility, and a seamless transition from in vitro to in vivo applications. I describe the development of a covalently cross-linked mimic of the extracellular matrix (sECM), now commercially available, for 3-D culture of cells in vitro and for translational use in vivo. These bio-inspired, biomimetic materials can be used "as is" in drug discovery, toxicology, cell banking, and, ultimately, medicine. For cell therapy and the development of clinical combination products, the sECM biomaterials must be highly reproducible, manufacturable, approvable, and affordable. To obtain integrated, functional, multicellular systems that recapitulate tissues and organs, the needs of the true end users, physicians and patients, must dictate the key design criteria. In chemical terms, the sECM consists of chemically-modified hyaluronan (HA), other glycosaminoglycans (GAGs), and ECM polypeptides containing thiol residues that are cross-linked using biocompatible polyvalent electrophiles. For example, co-cross-linking the semisynthetic thiol-modified HA-like GAG with thiol-modified gelatin produces Extracel as a hydrogel. This hydrogel may be formed in situ in the presence of cells or tissues to provide an injectable cell-delivery vehicle. Alternately, an Extracel hyrogel can be lyophilized to create a macroporous scaffold, which can then be employed for 3-D cell culture. In this Account, we describe four applications of sECMs that are relevant to the evaluation of drug efficacy and drug toxicity. First, the uses of sECMs to promote both in vitro and in vivo growth of healthy cellularized 3-D tissues are summarized. Primary or cell-line-derived cells, including fibroblasts, chondrocytes, hepatocytes, adult and embryonic stem cells, and endothelial and epithelial cells have been used. Second, primary hepatocytes retain their biochemical phenotypes and achieve greater longevity in 3-D culture in Extracel. This constitutes a new 3-D method for rapid evaluation of hepatotoxicity in vitro. Third, cancer cell lines are readily grown in 3-D culture in Extracel, offering a method for rapid evaluation of new anticancer agents in a more physiological ex vivo tumor model. This system has been used to evaluate signal transduction modifiers obtained from our research on lipid signaling. Fourth, a new "tumor engineering" xenograft model uses orthotopic injection of Extracel-containing tumor cells in nude mice. This approach allows production of patient-specific mice using primary human tumor samples and offers a superior metastatic cancer model. Future applications of the injectable cell delivery and 3-D cell culture methods include chemoattractant and angiogenesis assays, high-content automated screening of chemical libraries, pharmacogenomic and toxicogenomic studies with cultured organoids, and personalized treatment models. In summary, the sECM technology offers a versatile "translational bridge" from in vitro to in vivo to facilitate drug discovery in both academic and pharmaceutical laboratories.

Effects of extracellular matrix analogues on primary human fibroblast behavior

In vitro cell culture is a vital research tool for cell biology, pharmacology, toxicology, protein production, systems biology and drug discovery. Traditional culturing methods on plastic surfaces do not accurately represent the in vivo environment, and a paradigm shift from two-dimensional to three-dimensional (3-D) experimental techniques is underway. To enable this change, a variety of natural, synthetic and semi-synthetic extracellular matrix (ECM) equivalents have been developed to provide an appropriate cellular microenvironment. We describe herein an investigation of the properties of four commercially available ECM equivalents on the growth and proliferation of primary human tracheal scar fibroblast behavior, both in 3-D and pseudo-3-D conditions. We also compare subcutaneous tissue growth of 3-D encapsulated fibroblasts in vivo in two of these materials, Matrigel and Extracel. The latter shows increased cell proliferation and remodeling of the ECM equivalent. The results provide researchers with a rational basis for selection of a given ECM equivalent based on its biological performance in vitro and in vivo, as well as the practicality of the experimental protocols. Biomaterials that use a customizable glycosaminoglycan-based hydrogel appear to offer the most convenient and flexible system for conducting in vitro research that accurately translates to in vivo physiology needed for tissue engineering.