Wound Healing Promotion by Hyaluronic Acid: Effect of Molecular Weight on Gene Expression and In Vivo Wound Closure

In silico approaches for better understanding cysteine cathepsin-glycosaminoglycan interactions

Cysteine cathepsins constitute the largest cathepsin family, with 11 proteases in human that are present primarily within acidic endosomal and lysosomal compartments. They are involved in the turnover of intracellular and extracellular proteins. They are synthesized as inactive procathepsins that are converted to mature active forms. Cathepsins play important roles in physiological and pathological processes and, therefore, receive increasing attention as potential therapeutic targets. Their maturation and activity can be regulated by glycosaminoglycans (GAGs), long linear negatively charged polysaccharides composed of recurring dimeric units. In this review, we summarize recent computational progress in the field of (pro)cathepsin-GAG complexes analyses.

Comprehensive evaluation of xylometazoline hydrochloride formulations: Ex-vivo and in-vitro studies

Xylometazoline is a well-established nasal decongestant that has been used alone and in combination with dexpanthenol as an over the counter (OTC) medicine. Considering the possibility of further improvement of xylometazoline nasal formulations, hyaluronic acid (HA) was evaluated as an additional ingredient. The aim of this study was to investigate the permeation, mucosal retention, and mucoadhesion properties of a new xylometazoline-HA [Xylo-HA] formulation ex vivo and to explore the potential benefits of incorporating HA in the formulation in vitro. Sheep nasal mucosa was used in the ex vivo study, where Xylo-HA was compared with xylometazoline alone [Xylo-Mono], and in combination with dexpanthenol [Xylo-Dex] to understand the impact of formulation changes. The permeation of xylometazoline was generally low (Xylo-Mono 11.14 ± 4.75 %, Xylo-HA 14.57 ± 5.72 % and Xylo-Dex 11.00 ± 3.05 % of the applied dose). The steady state fluxes of xylometazoline were determined as 12.64 ± 3.52 μg/cm2h, 14.94 ± 3.38 μg/cm2h and 12.19 ± 2.05 μg/cm2h for Xylo-Mono, Xylo-HA and Xylo-Dex, respectively. No significant differences were observed between the formulations in the permeation nor mucosal retention studies (p > 0.05 for all), while Xylo-HA exhibited superior mucoadhesive proprieties (p < 0.05 for all). The effects on wound healing and barrier integrity of the three xylometazoline formulations were tested in vitro on HaCaT cells. To better elucidate the role of HA, an additional HA formulation without xylometazoline was prepared (HA-Mono). A scratch test was performed to evaluate wound healing, revealing that the test formulations did not achieve complete wound closure within 72 h and demonstrated a similar effect at the end of the testing period. To assess the effect on barrier integrity, cells were treated for 5 days with daily measurements of transepithelial electrical resistance (TEER). At the end of the experiment, Xylo-Dex showed a moderate 14 % increase in TEER, while Xylo-Mono did not significantly affect this parameter. TEER rose by 951 % in the Xylo-HA, and by 10497 % in the HA group, suggesting that incorporating HA led to enhanced barrier function. Further clinical studies are recommended to better understand the clinical implications and efficacy of the Xylo-HA formulation, with particular focus on the role of HA.

Transplantation of hyaluronic acid and menstrual blood-derived stem cells accelerated wound healing in a diabetic rat model

Diabetic wounds require a multifactorial approach because several factors are involved in its occurrence. Herein we investigated whether transplantation of hyaluronic acid (HA) in combination with menstrual blood derived stem cells (MenSCs) could promote healing in diabetic rats. Thirty days after induction of diabetes, sixty animals were randomly planned into four equal groups: the untreated group, HA group, MenSC group, and HA+MenSC group. Sampling was done for histological, molecular, and tensiometrical assessments. Our results indicated that the wound contraction rate, volumes of new epidermis and dermis, collagen density, as well as tensiometrical parameter were considerably increased in the treatment groups compared to the untreated group and these changes were more obvious in the HA+MenSC ones. In addition, the expression levels of TGF-β and VEGF genes were significantly upregulated in treatment groups in comparison with the untreated group and were greater in the HA+MenSC group. This is while expression levels of TNF-α and IL-1β genes were more considerably downregulated in the HA+MenSC group than the other groups. We concluded that the combined use of HA and MenSCs has more effects on diabetic wound healing.

Hyaluronate loaded advanced wound dressing in form of in situ forming hydrogel powders: Formulation, characterization, and therapeutic potential

In this paper, a blend composed of alginate-pectin-chitosan loaded with sodium hyaluronate in the form of an in situ forming dressing was successfully developed for wound repair applications. This complex polymeric blend has been efficiently used to encapsulate hyaluronate, forming an adhesive, flexible, and non-occlusive hydrogel able to uptake to 15 times its weight in wound fluid, and being removed without trauma from the wound site. Calorimetric and FT-IR studies confirmed chemical interactions between hyaluronate and polysaccharides blend, primarily related to the formation of a polyelectrolytic complex between hyaluronate and chitosan. In vivo wound healing assays on murine models highlighted the ability of the loaded hydrogels to significantly accelerate wound healing compared to a hyaluronic-loaded ointment. This was evident through complete wound closure in <10 days, accompanied by fully restored epidermal functionality and no indications of the site of excision or treatment. Therefore, all these results suggest that hyaluronate-loaded powders could be a very promising conformable dressing in several wound healing applications where exudate is present.

High molecular weight hyaluronic acid-liposome delivery system for efficient transdermal treatment of acute and chronic skin photodamage

Photodamage is one of the most common causes of skin injury. High molecular weight hyaluronic acid (HHA) has shown immense potential in the treatment of skin photodamage by virtue of its anti-inflammatory, reparative, and antioxidative properties. However, due to its large molecular structure of HHA, HHA solution could only form a protective film on the skin surface in conventional application, failing to effectively penetrate the skin, which necessitates the development of new delivery strategies. Liposomes, with a structure similar to biological membranes, have garnered extensive attention as transdermal drug delivery carriers because of their advantages in permeability, dermal compatibility, and biosafety. Herein, we have developed a HHA-liposome transdermal system (HHL) by embedding HHA into the liposome structure using reverse evaporation, high-speed homogenization, and micro-jet techniques. The effective penetration and long-term residence of HHA in skin tissue were multidimensionally verified, and the kinetics of HHA in the skin were extensively studied. Moreover, it was demonstrated that HHL significantly strengthened the activity of human keratinocytes and effectively inhibits photo-induced cellular aging in vitro. Furthermore, a murine model of acute skin injury induced by laser ablation was established, where the transdermal system showed significant anti-inflammatory and immunosuppressive properties, promoting skin proliferation and scar repair, thereby demonstrating immense potential in accelerating skin wound healing. Meanwhile, HHL significantly ameliorated skin barrier dysfunction caused by simulated sunlight exposure, inhibited skin erythema, inflammatory responses, and oxidative stress, and promoted collagen expression in a chronic photodamage skin model. Therefore, this transdermal delivery system with biocompatibility represents a promising new strategy for the non-invasive application of HHA in skin photodamage, revealing the significant potential for clinical translation and broad application prospects. STATEMENT OF SIGNIFICANCE: The transdermal system utilizing hyaluronic acid-based liposomes enhances skin permeability and retains high molecular weight hyaluronic acid (HHL). In vitro experiments with human keratinocytes demonstrate significant skin repair effects of HHL and its effective inhibition of cellular aging. In an acute photodamage model, HHL exhibits stronger anti-inflammatory and immunosuppressive properties, promoting skin proliferation and scar repair. In a chronic photodamage model, HHL significantly improves skin barrier dysfunction, reduces oxidative stress induced by simulated sunlight, and enhances collagen expression.

From Time to Timer in Wound Healing Through the Regeneration

Hard-to-heal wounds are an important public health issue worldwide, with a significant impact on the quality of life of patients. It is estimated that approximately 1-2% of the global population suffers from difficult wounds, which can be caused by a variety of factors such as trauma, infections, chronic diseases like diabetes or obesity, or poor health conditions. Hard-to-heal wounds are often characterized by a slow and complicated healing process, which can lead to serious complications such as infections, pressure ulcers, scar tissue formation, and even amputations. These complications can have a significant impact on the mobility, autonomy, and quality of life of patients, leading to an increase in healthcare and social costs associated with wound care. The preparation of the wound bed is a key concept in the management of hard-to-heal wounds, with the aim of promoting an optimal environment for healing. The TIME (Tissue, Infection/Inflammation, Moisture, Edge) model is a systematic approach used to assess and manage wounds in a targeted and personalized way. The concept of TIMER, expanding the TIME model, further focuses on regenerative processes, paying particular attention to promoting tissue regeneration and wound healing in a more effective and comprehensive way. The new element introduced in the TIMER model is "Regeneration", which highlights the importance of activating and supporting tissue regeneration processes to promote complete and lasting wound healing. Regenerative therapies can include a wide range of approaches, including cellular therapies, growth factors, bioactive biomaterials, stem cell therapies, and growth factor therapies. These therapies aim to promote the formation of new healthy tissues, reduce inflammation, improve vascularization, and stimulate cellular proliferation to accelerate wound closure and prevent complications. Thanks to continuous progress in research and development of regenerative therapies, more and more patients suffering from difficult wounds can benefit from innovative and promising solutions to promote faster and more effective healing, improve quality of life, and reduce the risk of long-term complications.

Citrus flavonoids-loaded chitosan derivatives-route nanofilm as drug delivery systems for cutaneous wound healing

This study focuses on creating new forms of biomimetic nanofiber composites by combining copolymerizing and electrospinning approaches in the field of nanomedicine. The process involved utilizing the melt polymerization of proline (Pr) and hydroxyl proline (Hyp) to synthesize polymers based on Pr (PPE) and Hyp (PHPE). These polymers were then used in a grafting copolymerization process with chitosan (CS) to produce PHPC (1560 ± 81.08 KDa). A novel electrospun nanofiber scaffold was then produced using PHPC and/or CS, hyaluronic acid, polyvinyl alcohol, and naringenin (NR) as a loading drug. Finally, Mouse Dermal Fibroblast (MDF) cells were introduced to the wound dressing and assessed their therapeutic potential for wound healing in rats. The scaffolds were characterized by FTIR, NMR, DSC, and SEM analysis, which confirmed the amino acid grafting, loading drug, and porous and nanofibrous structures (>225 nm). The results showed that the PHPC-based scaffolds were more effective for swelling/absorption of wound secretions, had more elasticity/elongation, faster drug release, more MDF-cytocompatibility, and antibacterial activity against multidrug-resistant S. aureus compared to CS-based scaffolds. The in vivo studies showed that NR in combination with MDF can accelerate cell migration/proliferation, and remodeling phases of wound healing in both PHPC/CS-based scaffolds. Moreover, PHPC-based scaffolds promote collagen content, and better wound contraction, epithelialization, and neovascularization than CS-based, showing potential as wound-dressing.

Topical application of a hyaluronic acid-based hydrogel integrated with secretome of human mesenchymal stromal cells for diabetic ulcer repair

This preclinical proof-of-concept study aimed to evaluate the effectiveness of secretome therapy in diabetic mice with pressure ulcers. We utilized a custom-made hyaluronic acid (HA)-based porous sponge, which was rehydrated either with normal culture medium or secretome derived from human mesenchymal stromal cells (MSCs) to achieve a hydrogel consistency. Following application onto skin ulcers, both the hydrogel-only and the hydrogel + secretome combination accelerated wound closure compared to the vehicle group. Notably, the presence of secretome significantly enhanced the healing effect of the hydrogel, as evidenced by a thicker epidermis and increased revascularization of the healed area compared to the vehicle group. Notably, molecular analysis of healed skin revealed significant downregulation of genes involved in delayed wound healing and abnormal inflammatory response in ulcers treated with the hydrogel + secretome combination, compared to those treated with the hydrogel only. Additionally, we found no significant differences in therapeutic outcomes when comparing the use of secretome from fetal dermal MSCs to that from umbilical cord MSCs. This observation is supported by the proteomic profile of the two secretomes, which suggests a shared molecular signature responsible of the observed therapeutic effects.

Multiscale Control of Nanofiber-Composite Hydrogel for Complex 3D Cell Culture by Extracellular Matrix Composition and Nanofiber Alignment

In order to manipulate the complex behavior of cells in a 3-dimensional (3D) environment, it is important to provide the microenvironment that can accurately portray the complexity of highly anisotropic tissue structures. However, it is technically challenging to generate a complex microenvironment using conventional biomaterials that are mostly isotropic with limited bioactivity. In this study, the gelatin-hyaluronic acid hydrogel incorporated with aqueous-dispersible, short nanofibers capable of in situ alignment is developed to emulate the native heterogeneous extracellular matrix consisting of fibrous and non-fibrous components. The gelatin nanofibers containing magnetic nanoparticles, which could be aligned by external magnetic field, are dispersed and embedded in gelatin-hyaluronic acid hydrogel encapsulated with dermal fibroblasts. The aligned nanofibers via magnetic field could be safely integrated into the hydrogel, and the process could be repeated to generate larger 3D hydrogels with variable nanofiber alignments. The aligned nanofibers in the hydrogel can more effectively guide the anisotropic morphology (e.g., elongation) of dermal fibroblasts than random nanofibers, whereas myofibroblastic differentiation is more prominent in random nanofibers. At a given nanofiber configuration, the hydrogel composition having intermediate hyaluronic acid content induces myofibroblastic differentiation. These results indicate that modulating the degree of nanofiber alignment and the hyaluronic acid content of the hydrogel are crucial factors that critically influence the fibroblast phenotypes. The nanofiber-composite hydrogel capable of directional nanofiber alignment and tunable material composition can effectively induce a wide array of phenotypic plasticity in 3D cell culture.

Elderberry Leaves with Antioxidant and Anti-Inflammatory Properties as a Valuable Plant Material for Wound Healing

Sambuci folium (elderberry leaves) have been used in traditional medicine, mainly externally, to treat skin diseases and wounds. Therefore, the aim of this study was to screen the biological activity of elderberry leaves (antioxidant potential and possibility of inhibition of tyrosinase and hyaluronidase enzymes) combined with phytochemical analysis. For this purpose, a phytochemical analysis was carried out. Elderberry leaves of 12 varieties ("Sampo", "Obelisk", "Dwubarwny", "Haschberg", "Haschberg 1", "Koralowy", "Sambo", "Black Beauty", "Black Tower", "Golden hybrid", "Samyl", "Samyl 1") in two growth stages. The compounds from the selected groups, phenolic acids (chlorogenic acid) and flavonols (quercetin), were chromatographically determined in hydroalcoholic leaf extracts. All tested elderberry leaf extracts showed antioxidant effects, but the most promising potential: very high compounds content (TPC = 61.85 mg GAE/g), antioxidant (e.g., DPPH IC50 = 1.88 mg/mL; CUPRAC IC0.5 = 0.63 mg/mL) and optimal anti-inflammatory (inhibition of hyaluronidase activity 41.28%) activities were indicated for older leaves of the "Sampo" variety. Additionally, the extract obtained from "Sampo" and "Golden hybrid" variety facilitated the treatment of wounds in the scratch test. In summary, the best multidirectional pro-health effect in treating skin inflammation was specified for "Sampo" leaves II extract (leaves during the flowering period); however, wound treatment was noted as rich in chlorogenic acid younger leaf extracts of the "Golden hybrid" variety.

Bioarchitectural Design of Bioactive Biopolymers: Structure-Function Paradigm for Diabetic Wound Healing

Chronic wounds such as diabetic ulcers are a major complication in diabetes caused by hyperglycemia, prolonged inflammation, high oxidative stress, and bacterial bioburden. Bioactive biopolymers have been found to have a biological response in wound tissue microenvironments and are used for developing advanced tissue engineering strategies to enhance wound healing. These biopolymers possess innate bioactivity and are biodegradable, with favourable mechanical properties. However, their bioactivity is highly dependent on their structural properties, which need to be carefully considered while developing wound healing strategies. Biopolymers such as alginate, chitosan, hyaluronic acid, and collagen have previously been used in wound healing solutions but the modulation of structural/physico-chemical properties for differential bioactivity have not been the prime focus. Factors such as molecular weight, degree of polymerization, amino acid sequences, and hierarchical structures can have a spectrum of immunomodulatory, anti-bacterial, and anti-oxidant properties that could determine the fate of the wound. The current narrative review addresses the structure-function relationship in bioactive biopolymers for promoting healing in chronic wounds with emphasis on diabetic ulcers. This review highlights the need for characterization of the biopolymers under research while designing biomaterials to maximize the inherent bioactive potency for better tissue regeneration outcomes, especially in the context of diabetic ulcers.

Naked mole-rat hyaluronan

Naked mole rats (NMRs) are renowned for their exceptional longevity and remarkable maintenance of health throughout their lifetime. Their subterranean lifestyle has led to adaptations that have resulted in elevated levels of a very high molecular weight hyaluronan in their tissues. Hyaluronan, a glycosaminoglycan, is a key component of the extracellular matrix, which plays a critical role in maintaining tissue structure and regulating cell signaling pathways. This phenomenon in NMRs is attributed to a higher processing and production capacity by some of their hyaluronan synthases, along with lower degradation by certain hyaluronidases. Furthermore, this adaptation indirectly confers several advantages to NMRs, such as the preservation of skin elasticity and youthful appearance, accelerated wound healing, protection against oxidative stress, and resistance to conditions such as cancer and arthritis, largely attributable to CD44 signaling and other intricate mechanisms. Thus, the main objective of this study was to conduct a comprehensive study of the distinctive features of NMR hyaluronan, particularly emphasizing the currently known molecular mechanisms that contribute to its beneficial properties. Furthermore, this research delves into the potential applications of NMR hyaluronan in both cosmetic and therapeutic fields, as well as the challenges involved.

Multifunctional Therapeutic Nanodiamond Hydrogels for Infected-Wound Healing and Cancer Therapy

Wound infection and tumor recurrence are the two main threats to cancer patients after surgery. Although researchers have developed new treatment systems to address the two significant challenges simultaneously, the potential side effects of the heavy-metal-ion-based treatment systems still severely limit their widespread application in therapy. In addition, the wounds from tumor removal compared with general operative wounds are more complex. The tumor wounds mainly exhibit more hemorrhage, larger trauma area, greater vulnerability to bacterial infection, and residual tumor cells. Therefore, a multifunctional treatment platform is urgently needed to integrate rapid hemostasis, sterilization, wound healing promotion, and antitumor functions. In this work, nanodiamonds (NDs), a material that has been well proven to have excellent biocompatibility, are added into a solution of acrylic-grafted chitosan (CEC) and oxidized hyaluronic acid (OHA) to construct a multifunctional treatment platform (CEC-OHA-NDs). The hydrogels exhibit rapid hemostasis, a wound-healing-promoting effect, excellent self-healing, and injectable abilities. Moreover, CEC-OHA-NDs can effectively eliminate bacteria and inhibit tumor proliferation by the warm photothermal effect of NDs under tissue-penetrable near-infrared laser irradiation (NIR) without cytotoxicity. Consequently, we adopt a simple and convenient strategy to construct a multifunctional treatment platform using carbon-based nanomaterials with excellent biocompatibility to promote the healing of infected wounds and to inhibit tumor cell proliferation simultaneously.

Low-adhesion and low-swelling hydrogel based on alginate and carbonated water to prevent temporary dilation of wound sites

Hydrogel-based wound dressings have been developed for rapid wound healing; however, their adhesive properties have not been adequately investigated. Excessive adhesion to the skin causes wound expansion and pain when hydrogels absorb exudates and swell at wound sites. Herein, we developed a low-adhesion and low-swelling hydrogel dressing using alginate, which is non-adhesive to cells and skin tissue, CaCO3, and carbonated water. The alginate/CaCO3 solution rapidly formed a hydrogel upon the addition of carbonated water, and the CO2 in the hydrogel diffused into the atmosphere, preventing acidification and obtaining a pH value suitable for wound healing. Remarkably, the skin adhesion and swelling of the hydrogel were 11.9- to 16.5-fold and 1.9-fold lower, respectively, than those of clinical low-adhesion hydrogel dressings. In vivo wound-healing tests in mice demonstrated its therapeutic efficacy, and the prepared hydrogel prevented temporary wound dilation during early healing. These results illustrate the importance of controlling skin adhesion and swelling in wound dressings and demonstrate the potential clinical applications of this wound-friendly hydrogel dressing.

Exosomes derived from adipose stem cells in combination with hyaluronic acid promote diabetic wound healing

Diabetic wound is one of the main challenges in dermatology. Although stem cell-based treatment has therapeutic benefits in wound repair, the clinical application is still limited. Herein we investigated whether adipose stem cells -derived exosomes (Exo) loaded on hyaluronic acid (HA) could promote healing in diabetic rats. Sixty diabetic rats were randomly planned into the control group, Exo group, HA group, and HA+Exo group. On days 7, 14, and 21, five rats from each group were sampled for stereological, molecular, and tensiometrical assessments. Our results indicated that the wound closure rate, the total volumes of new epidermis and dermis, the numerical densities of fibroblasts, the length density blood vessels, collagen density as well as tensiometrical parameters of the healed wounds were significantly higher in the treated groups than in the control group, and these changes were more obvious in the HA+Exo ones. Furthermore, the expression of TGF-β and VEGF genes were meaningfully upregulated in all treated groups compared to the control group and were greater in the HA+Exo group. This is while expression of TNF-α and IL-1β, as well as numerical densities of neutrophils decreased more considerably in the HA+Exo group in comparison to the other groups. Generally, it was found that using both HA injection and exosomes has more effect on diabetic wound healing.

Evaluation of the Effect of Honey-Containing Chitosan/Hyaluronic Acid Hydrogels on Wound Healing

The 3D polymeric network structure of hydrogels imitates the extracellular matrix, thereby facilitating cell growth and differentiation. In the current study, chitosan/hyaluronic acid/honey coacervate hydrogels were produced without any chemicals or crosslinking agents and investigated for their wound-healing abilities. Chitosan/hyaluronic acid/honey hydrogels were characterized by FTIR, SEM, and rheology analysis. Moreover, their water content, water uptake capacities, and porosity were investigated. In FT-IR spectra, it was discovered that the characteristic band placement of chitosan with hyaluronic acid changed upon interacting with honey. The porosity of the honey-containing hydrogels (12%) decreased compared to those without honey (17%). Additionally, the water-uptake capacity of honey-containing hydrogels slightly decreased. Also, it was observed that hydrogels' viscosity increased with the increased hyaluronic acid amount and decreased with the amount of honey. The adhesion and proliferation of fibroblast cells on the surface of hydrogel formulations were highest in honey-containing hydrogels (144%). In in vivo studies, wound healing was accelerated by honey addition. It has been demonstrated for the first time that honey-loaded chitosan-hyaluronic acid hydrogels, prepared without the use of toxic covalent crosslinkers, have potential for use in wound healing applications.

In Situ Forming Bioartificial Hydrogels with ROS Scavenging Capability Induced by Gallic Acid Release with Potential in Chronic Skin Wound Treatment

In normal chronic wound healing pathways, the presence of strong and persistent inflammation states characterized by high Reactive Oxygen Species (ROS) concentrations is one of the major concerns hindering tissue regeneration. The administration of different ROS scavengers has been investigated over the years, but their effectiveness has been strongly limited by their short half-life caused by chronic wound environmental conditions. This work aimed at overcoming this criticism by formulating bioartificial hydrogels able to preserve the functionalities of the encapsulated scavenger (i.e., gallic acid-GA) and expand its therapeutic window. To this purpose, an amphiphilic poly(ether urethane) exposing -NH groups (4.5 × 1020 units/gpolymer) was first synthesized and blended with a low molecular weight hyaluronic acid. The role exerted by the solvent on system gelation mechanism and swelling capability was first studied, evidencing superior thermo-responsiveness for formulations prepared in saline solution compared to double demineralized water (ddH2O). Nevertheless, drug-loaded hydrogels were prepared in ddH2O as the best compromise to preserve GA from degradation while retaining gelation potential. GA was released with a controlled and sustained profile up to 48 h and retained its scavenger capability against hydroxyl, superoxide and 1'-diphenyl-2-picrylhydrazyl radicals at each tested time point. Moreover, the same GA amounts were able to significantly reduce intracellular ROS concentration upon oxidative stress induction. Lastly, the system was highly cytocompatible according to ISO regulation and GA-enriched extracts did not induce NIH-3T3 morphology changes.

Clinical, histological, immunohistochemical, and biomolecular analysis of hyaluronic acid in early wound healing of human gingival tissues: A randomized, split-mouth trial

BACKGROUND

Hyaluronic acid (HA) exerts a fundamental role in tissue repair. In vitro and animal studies demonstrated its ability to enhance wound healing. Nevertheless, in vivo human studies evaluating mechanisms involved in oral soft tissue repair are lacking. The aim of this study was to evaluate the in vivo effect of HA on early wound healing of human gingival (G) tissues.

METHODS

In the present randomized, split-mouth, double-blind, clinical trial, G biopsies were obtained in eight patients 24 h post-surgery after HA application (HA group) and compared with those obtained from the same patients without HA application (no treatment; NT group). Clinical response was evaluated through the Early Wound Healing Score (EHS). Microvascular density (MVD), collagen content and cellular proliferation were evaluated through sirius red and Masson trichrome staining, and Ki-67 immunohistochemistry, respectively. To assess collagen turnover, MMP-1, MMP-2, MMP-9, TGF-β1 protein levels and LOX, MMP1, TIMP1, TGFB1 gene expression were analyzed by western blot and real time polymerase chain reaction.

RESULTS

Twenty-four hours after surgery, the EHS was significantly higher in the HA group. MVD, collagen content, and cell proliferation were not affected. LOX mRNA, MMP-1 protein, and TIMP1 gene expression were significantly upregulated in the HA compared to the NT group.

CONCLUSIONS

The additional use of 0.8% HA gel does not modify new blood vessel growth in the early phase of gingival wound healing. Concerning the secondary outcomes, HA seems to enhance extracellular matrix remodeling and collagen maturation, which could drive early wound healing of G tissues to improve clinical parameters.

Extraction Optimization, Antioxidant, Cosmeceutical and Wound Healing Potential of Echinacea purpurea Glycerolic Extracts

Echinacea purpurea is a plant with immunomodulating properties, often used in topical preparations for treatment of small superficial wounds. In the presented study, the best conditions for ultrasound-assisted extraction of caffeic acid derivatives (caftaric and cichoric acid) (TPA-opt extract), as well as the conditions best suited for preparation of the extract with high radical scavenging activity (RSA-opt extract), from E. purpurea aerial parts were determined. A Box-Behnken design based on glycerol content (%, w/w), temperature (°C), ultrasonication power (W) and time (min) as independent variables was performed. Antioxidant, antiaging and wound healing effects of the two prepared extracts were evaluated. The results demonstrate that glycerol extraction is a fast and efficient method for preparation of the extracts with excellent radical scavenging, Fe²⁺ chelating and antioxidant abilities. Furthermore, the extracts demonstrated notable collagenase, elastase and tyrosinase inhibitory activity, indicating their antiaging properties. Well-pronounced hyaluronidase-inhibitory activities, with IC₅₀ values lower than 30 μL extract/mL, as well as the ability to promote scratch closure in HaCaT keratinocyte monolayers, even in concentrations as low as 2.5 μL extract/mL (for RSA-opt), demonstrate promising wound healing effects of E. purpurea. The fact that the investigated extracts were prepared using glycerol, a non-toxic and environmentally friendly solvent, widely used in cosmetics, makes them suitable for direct use in specialized cosmeceutical formulations.

Molecularly Imprinted Nanomaterials with Stimuli Responsiveness for Applications in Biomedicine

The review aims to summarize recent reports of stimuli-responsive nanomaterials based on molecularly imprinted polymers (MIPs) and discuss their applications in biomedicine. In the past few decades, MIPs have been proven to show widespread applications as new molecular recognition materials. The development of stimuli-responsive nanomaterials has successfully endowed MIPs with not only affinity properties comparable to those of natural antibodies but also the ability to respond to external stimuli (stimuli-responsive MIPs). In this review, we will discuss the synthesis of MIPs, the classification of stimuli-responsive MIP nanomaterials (MIP-NMs), their dynamic mechanisms, and their applications in biomedicine, including bioanalysis and diagnosis, biological imaging, drug delivery, disease intervention, and others. This review mainly focuses on studies of smart MIP-NMs with biomedical perspectives after 2015. We believe that this review will be helpful for the further exploration of stimuli-responsive MIP-NMs and contribute to expanding their practical applications especially in biomedicine in the near future.

Preparation of Nano/Microcapsules of Ozonated Olive Oil in Hyaluronan Matrix and Analysis of Physicochemical and Microbiological (Biological) Properties of the Obtained Biocomposite

Hydrogels, based on natural polymers, such as hyaluronic acid, are gaining an increasing popularity because of their biological activity. The antibacterial effect of ozone is widely known and used, but the instability the gas causes, severely limits its application. Ozone entrapment in olive oil by its reaction with an unsaturated bond, allows for the formation of stable, therapeutically active ozone derivatives. In this study, we obtained an innovative hydrogel, based on hyaluronic acid containing micro/nanocapsules of ozonated olive oil. By combination of the biocompatible polymer with a high regenerative capacity and biologically active ingredients, we obtained a hydrogel with regenerative properties and a very weak inhibitory effect against both bacterial commensal skin microbiota and pathogenic Candida-like yeasts. We assessed the stability and rheological properties of the gel, determined the morphology of the composite, using scanning electron microscopy (SEM) and particle size by the dynamic light scattering (DLS) method. We also performed Attenuated total reflectance Fourier transform infrared (FTIR-ATR) spectroscopy. The functional properties, including the antimicrobial potential were assessed by the microbiological analysis and in vitro testing on the HaCat human keratinocyte cell line. The studies proved that the obtained emulsions were rheologically stable, exhibited an antimicrobial effect and did not show cytotoxicity in the HaCat keratinocyte model.

PLGA/Gelatin/Hyaluronic Acid Fibrous Membrane Scaffold for Therapeutic Delivery of Adipose-Derived Stem Cells to Promote Wound Healing

Hyaluronic acid (HA) has been suggested to be a preferential material for the delivery of adipose-derived stem cells (ASCs) in wound healing. By incorporating HA in electrospun poly (lactide-co-glycolide) (PLGA)/gelatin (PG) fibrous membrane scaffolds (FMS), we aim to fabricate PLGA/gelatin/HA (PGH) FMS to provide a milieu for 3D culture and delivery of ASCs. The prepared FMS shows adequate cytocompatibility and is suitable for attachment and growth of ASCs. Compared with PG, the PGH offers an enhanced proliferation rate of ASCs, shows higher cell viability, and better maintains an ASC-like phenotype during in vitro cell culture. The ASCs in PGH also show upregulated expression of genes associated with angiogenesis and wound healing. From a rat full-thickness wound healing model, a wound treated with PGH/ASCs can accelerate the wound closure rate compared with wounds treated with PGH, alginate wound dressing, and gauze. From H&E and Masson's trichrome staining, the PGH/ASC treatment can promote wound healing by increasing the epithelialization rate and forming well-organized dermis. This is supported by immunohistochemical staining of macrophages and α-smooth muscle actin, where early recruitment of macrophages, macrophage polarization, and angiogenesis was found due to the delivered ASCs. The content of type III collagen is also higher than type I collagen within the newly formed skin tissue, implying scarless wound healing. Taken together, using PGH FMS as a topical wound dressing material for the therapeutic delivery of ASCs, a wound treated with PGH/ASCs was shown to accelerate wound healing significantly in rats, through modulating immunoreaction, promoting angiogenesis, and reducing scar formation at the wound sites.

Self-assembled polyelectrolyte complexes of chitosan and fucoidan for sustained growth factor release from PRP enhance proliferation and collagen deposition in diabetic mice

Diabetic wound management is a serious health care challenge due to higher rates of relapse, expensive treatment approaches, and poor healing outcomes. Among cell-based therapies, use of platelet-rich plasma (PRP) has been shown to be effective for diabetic wounds, but its poor shelf-life limits its clinical use. Here, we demonstrate a simple but effective polymer system to increase the shelf-life of PRP by developing a polyelectrolyte complex with dropwise addition of chitosan solution containing PRP by simple mixing at room temperature. Thus, prepared chitosan-fucoidan (CF) carrier complex encapsulated more than 95% of the loaded PRP. The resulting CF/PRP colloids were spherical in shape and ensured extended PRP release up to 72 h at 37 °C. Routine characterization (FT-IR, XRD, SEM) showed the material properties. The biological assays showed that CF complexes were biocompatible while CF/PRP enhanced the proliferation of fibroblasts and keratinocytes via higher Ki67 expression and fibroblast migration. Further investigations using a diabetic mouse model demonstrated significantly higher wound contraction and histopathological observations showed increased fibroblast migration, and collagen and cytokeratin deposition in treatment groups. The results are suggestive of the efficacy of CF/PRP as a cost-effective topical formulation for the sustained delivery of growth factors in treating chronic diabetic wounds.

Production and application of biomaterials based on polyvinyl alcohol (PVA) as wound dressing: A mini review

The development of ideal wound dressing with excellent properties, such as exudate absorption capacity, drug release control ability, and increased wound healing, is currently a major requirement for wound healing. Polyvinyl alcohol (PVA) is a biodegradable semi-crystalline synthetic polymer that has been used in the field of biotechnology such as tissue regeneration, wound dressing, and drug delivery systems. In recent years, PVA-based wound dressing materials have received considerable attention due to their excellent properties such as biodegradability, biocompatibility, non-toxicity and low cost. PVA can be used as a wound dressing material to create the necessary moist wound environment, improve the physical properties of the dressing, and increase the wound healing rates. In addition, PVA can also be mixed with other organic and inorganic materials and can be used for drug delivery and wound healing. This review article addresses the role of biomaterials based on PVA mixed with other ingredients for wound dressing. It also focuses on its recent use in wound dressings as carriers of active substances.

Independent Control of Molecular Weight, Concentration, and Stiffness of Hyaluronic Acid Hydrogels

Hyaluronic acid (HA) hydrogels have been used for a multitude of applications, perhaps most notably for tissue engineering and regenerative medicine, owing to the versatility of the polymer and its tunable nature. Various groups have investigated the impact of hydrogel parameters (e.g., molecular weight, concentration, stiffness, etc.) in vitro and in vivo to achieve desired material performance characteristics. A limitation in the literature to date has been that altering one hydrogel parameter (a 'manipulated variable') to achieve a given hydrogel characteristic (a 'controlled variable') changes two variables at a time (e.g., altering molecular weight and/or concentration to investigate cell response to stiffness). Therefore, if cell responses differ, it may be possible that more than one variable caused the changes in observed responses. In the current study, we leveraged thiol-ene click chemistry with a crosslinker to develop a method that minimizes material performance changes and permitted multiple material properties to be independently held constant to evaluate a single variable at a time. Independent control was accomplished by tuning the concentration of crosslinker to achieve an effectively constant stiffness for different HA hydrogel molecular weights and polymer concentrations. Specific formulations were thereby identified that enabled the molecular weight (76 - 1550 kDa), concentration (2 - 10%), or stiffness (~1 - 350 kPa) to be varied while the other two were held constant, a key technical achievement. The response of rat mesenchymal stem cells to varying molecular weight, concentration, and stiffness demonstrated consistent upregulation of osteocalcin gene expression. The methodology presented to achieve independent control of hydrogel parameters may potentially be adopted by others for alternative hydrogel polymers, cell types, or cell culture medium compositions to minimize confounding variables in experimental hydrogel designs.

Development, characterization and in vivo evaluation of the ointment containing hyaluronic acid for potential wound healing applications

Wound healing is a complex biological process. In this context, hyaluronic acid (HA) plays an important role in all phases of wound healing, from inflammation to the remodelling process. Nevertheless, its presence in adults decreases by 50% compared to newborns, which drastically reduces tissue regeneration. In this sense, this work presented a new method of extracting HA from chicken combs, as well as the development and in vivo evaluation of an ointment composed of vaseline, lanolin and HA 1% (w/w) for wound healing. The rheological analysis showed that the ointment containing HA has a viscoelastic behaviour. The in vivo test showed on the 7^th day that the group treated with the ointment containing HA had a wound area of 0.07 cm² against 0.09 cm² of the ointment without HA (vaseline, and lanolin). On the other hand, the groups treated with the HA ointment had a higher mean percentage of collagen and better healing on the 14^th day. The results of this paper indicate that the new method used to obtain HA is feasible, low-cost, and easy to obtain. Furthermore, the HA containing ointment improved wound healing. Therefore, the obtained ointment has great potential for use as an effective biomaterial in wound healing.

Polysaccharide-based nanofibers for pharmaceutical and biomedical applications: A review

Nanofibers are fibrous nanocarriers that can be synthesized from natural polymers, synthetic polymers, semiconducting materials, composite materials, and carbon-based materials. Recently, natural polysaccharides-based nanofibers are gaining attention in the field of pharmaceuticals and biomedical as these are biocompatible, biodegradable, non-toxic, and economic. Nanofibers can deliver a significant amount of drug to the targeted site and provide effective interaction of therapeutic agent at the site of action due to a larger surface area. Other important advantages of nanofibers are low density, high porosity, small pore size, high mechanical strength, and low cost. In this review, natural polysaccharides such as alginate, pullulan, hyaluronic acid, dextran, cellulose, chondroitin sulfate, chitosan, xanthan gum, and gellan gum are discussed for their characteristics, pharmaceutical utility, and biomedical applications. The authors have given particular emphasis to the several fabrication processes that utilize these polysaccharides to form nanofibers, and their recent updates in pharmaceutical applications such as drug delivery, tissue engineering, skin disorders, wound-healing dressings, cancer therapy, bioactive molecules delivery, anti-infectives, and solubility enhancement. Despite these many advantages, nanofibers have been explored less for their scale-up and applications in advanced therapeutic delivery.

Hyaluronic Acid-Based Nanomaterials as a New Approach to the Treatment and Prevention of Bacterial Infections

Bacterial contamination of medical devices is a great concern for public health and an increasing risk for hospital-acquired infections. The ongoing increase in antibiotic-resistant bacterial strains highlights the urgent need to find new effective alternatives to antibiotics. Hyaluronic acid (HA) is a valuable polymer in biomedical applications, partly due to its bactericidal effects on different platforms such as contact lenses, cleaning solutions, wound dressings, cosmetic formulations, etc. Because the pure form of HA is rapidly hydrolyzed, nanotechnology-based approaches have been investigated to improve its clinical utility. Moreover, a combination of HA with other bactericidal molecules could improve the antibacterial effects on drug-resistant bacterial strains, and improve the management of hard-to-heal wound infections. This review summarizes the structure, production, and properties of HA, and its various platforms as a carrier in drug delivery. Herein, we discuss recent works on numerous types of HA-based nanoparticles to overcome the limitations of traditional antibiotics in the treatment of bacterial infections. Advances in the fabrication of controlled release of antimicrobial agents from HA-based nanosystems can allow the complete eradication of pathogenic microorganisms.

Development of secretome-based strategies to improve cell culture protocols in tissue engineering

Advances in skin tissue engineering have promoted the development of artificial skin substitutes to treat large burns and other major skin loss conditions. However, one of the main drawbacks to bioengineered skin is the need to obtain a large amount of viable epithelial cells in short periods of time, making the skin biofabrication process challenging and slow. Enhancing skin epithelial cell cultures by using mesenchymal stem cells secretome can favor the scalability of manufacturing processes for bioengineered skin. The effects of three different types of secretome derived from human mesenchymal stem cells, e.g. hADSC-s (adipose cells), hDPSC-s (dental pulp) and hWJSC-s (umbilical cord), were evaluated on cultured skin epithelial cells during 24, 48, 72 and 120 h to determine the potential of this product to enhance cell proliferation and improve biofabrication strategies for tissue engineering. Then, secretomes were applied in vivo in preliminary analyses carried out on Wistar rats. Results showed that the use of secretomes derived from mesenchymal stem cells enhanced currently available cell culture protocols. Secretome was associated with increased viability, proliferation and migration of human skin epithelial cells, with hDPSC-s and hWJSC-s yielding greater inductive effects than hADSC-s. Animals treated with hWJSC-s and especially, hDPSC-s tended to show enhanced wound healing in vivo with no detectable side effects. Mesenchymal stem cells derived secretomes could be considered as a promising approach to cell-free therapy able to improve skin wound healing and regeneration.

Copper-Hydrazide Coordinated Multifunctional Hyaluronan Hydrogels for Infected Wound Healing

Bacterial infection and delayed healing are two major obstacles in cutaneous wound management, and developing multifunctional hydrogels with antibacterial and prohealing capabilities presents a promising strategy to dress wounds. However, the simple and facile fabrication of such hydrogel dressings remains challenging. Herein, we report the first observation on hydrazide-metal coordination crosslinking that is utilized to successfully construct a series of hyaluronan (HA)-metal hydrogels by mixing hydrazided HA and metal ion solutions. Considering the antibacterial, prohealing, and proangiogenic properties of HA and Cu(II), as a proof of principle, a HA-Cu hydrogel was systematically investigated as a wound dressing. Surprisingly, the hydrazide-Cu(II) coordination was dynamic in nature and imparted the HA-Cu hydrogel with physicochemical multifunctions, including spontaneous self-healing, shear-thinning injectability, reversible pH/redox/ion pair triple responsiveness, etc. Moreover, the HA-Cu hydrogel exhibited a robust broad-spectrum antibacterial activity and could significantly accelerate infectious wound healing. Impressively, glutathione-triggered hydroxyl radical generation further potentiated wound healing, providing a paradigm for on-demand antibacterial activity enhancement. Hence, the HA-Cu hydrogel is a clinically applicable "smart" dressing for multi-scenario wound healing. We envision that the simple and versatile coordination approach opens up a new avenue to develop multifunctional hydrogels and shows great potential in frontier fields, such as biomedicine, wearable devices, and soft robots.

Enhanced Anti-Skin-Aging Activity of Yeast Extract-Treated Resveratrol Rice DJ526

Resveratrol is a powerful antioxidant that defends against oxidative stress in cells but is not found in large quantities in plants. Resveratrol-enriched rice DJ526, which was developed as a functional crop, shows a diverse range of biological activities. Resveratrol production is measured as total resveratrol and its glycoside, piceid, which is mainly found in plant-derived resveratrol. In the present study, elicitation using yeast extract (YE), methyl jasmonate, and jasmonic acid increased resveratrol production in DJ526 rice seeds. DJ526 seeds elicited using 1 g/L (YE1) and 5 g/L yeast extract (YE5) showed enhanced resveratrol production and antioxidant activity. YE5-treated DJ526 seeds showed decreased melanin content by 46.1% and 37.0% compared with the negative control and DJ526 (non-elicitation), respectively. Both YE1 and YE5 efficiently improved the wound-healing activity by reducing the wound gap faster than in untreated cells, with a maximum rate of 60.2% at 24 h and complete closure at 48 h. YE1 and YE5 significantly decreased the levels of proinflammatory cytokine, TNF-α, and enhanced collagen synthesis in inflammatory cells. These findings indicate that YE-treated resveratrol rice DJ526 may improve resveratrol production and could be an active antiaging ingredient for cosmetic and skin therapy applications.

Combination of Two Kinds of Medicated Microparticles Based on Hyaluronic Acid or Chitosan for a Wound Healing Spray Patch

Olive leaves extract (OLE) has been extensively studied as antioxidant and antibiotic and these characteristics make it particularly interesting for use on wounds. For this reason, the aim of this study was to introduce OLE in microparticles (MP) of hyaluronic acid (MPHA-OLE) or chitosan (MPCs-OLE) to obtain a spray patch for the treatment of wounds in anatomical areas that are difficult to protect with traditional patches. The MP were characterized for particle size and ability to protect OLE from degradation, to absorb water from wound exudate, to control OLE release from MP. The MPHA and MPCs medicated or not and mixtures of the two types in different proportions were studied in vitro on fibroblasts by the scratch wound healing assay. The MP size was always less than 5 µm, and therefore, suitable for a spray patch. The MPCs-OLE could slow down the release of OLE therefore only about 60% of the polyphenols contained in it were released after 4 h. Both MPHA and MPCs could accelerate wound healing. A 50% MPHA-OLE-50% MPCs-OLE blend was the most suitable for accelerating wound healing. The MPHA-OLE-MPCs-OLE blends studied in this work were shown to have the characteristics suitable for a spray patch, thus giving a second life to the waste products of olive growers.

Hyaluronan Functions in Wound Repair That Are Captured to Fuel Breast Cancer Progression

Signaling from an actively remodeling extracellular matrix (ECM) has emerged as a critical factor in regulating both the repair of tissue injuries and the progression of diseases such as metastatic cancer. Hyaluronan (HA) is a major component of the ECM that normally functions in tissue injury to sequentially promote then suppress inflammation and fibrosis, a duality in which is featured, and regulated in, wound repair. These essential response-to-injury functions of HA in the microenvironment are hijacked by tumor cells for invasion and avoidance of immune detection. In this review, we first discuss the numerous size-dependent functions of HA and emphasize the multifunctional nature of two of its receptors (CD44 and RHAMM) in regulating the signaling duality of HA in excisional wound healing. This is followed by a discussion of how HA metabolism is de-regulated in malignant progression and how targeting HA might be used to better manage breast cancer progression.

Preparation of Foam Dressings Based on Gelatin, Hyaluronic Acid, and Carboxymethyl Chitosan Containing Fibroblast Growth Factor-7 for Dermal Regeneration

Wound recovery close to the function of the native skin is the goal of wound healing. In this study, we prepared foam dressings (FDs; 2-GHC-FD-1-9, 5-GHC-FD-1-9, and 10-GHC-FD-1-9) composed of various concentrations of gelatin, hyaluronic acid, and carboxymethyl chitosan, which are chemically interconnected through amide bond formation, for evaluating wound healing. Tensile and cell proliferation tests showed that 2-GHC-FD-1-9 are suitable for wound dressing. For further evaluation, three types of FDs, 2-GHC-FD-1, 2-GHC-FD-4, and 2-GHC-FD-8 were chosen. The results of animal intradermal reactivity, water vapor transmission rate, and absorption rate of the three FDs indicated that 2-GHC-FD-8 is the most appropriate scaffold for wound healing. For wound healing acceleration, various concentrations of fibroblast growth factor-7 (FGF-7) was soaked in 2-GHC-FD-8 (2-GHC-FD-8/F1-6) and evaluated by using scanning electron microscopy, cell proliferation, release behavior, and in vivo animal tests. The FDs showed interconnected porous structures, increased cell proliferation until 8.0 × 10-11 M, controlled release with initial burst within 1 h, and sustained release for 48 h. The results of the animal test showed an appropriate concentration of FGF-7 for wound healing. In addition, 2-GHC-FD-8 is a suitable scaffold for wound healing. Therefore, we suggest that 2-GHC-FD-8/F3 is a useful wound dressing for accelerating wound healing.

A Review on the Enhancement of Calcium Phosphate Cement with Biological Materials in Bone Defect Healing

Calcium phosphate cement (CPC) is a promising material used in the treatment of bone defects due to its profitable features of self-setting capability, osteoconductivity, injectability, mouldability, and biocompatibility. However, the major limitations of CPC, such as the brittleness, lack of osteogenic property, and poor washout resistance, remain to be resolved. Thus, significant research effort has been committed to modify and reinforce CPC. The mixture of CPC with various biological materials, defined as the materials produced by living organisms, have been fabricated by researchers and their characteristics have been investigated in vitro and in vivo. This present review aimed to provide a comprehensive overview enabling the readers to compare the physical, mechanical, and biological properties of CPC upon the incorporation of different biological materials. By mixing the bone-related transcription factors, proteins, and/or polysaccharides with CPC, researchers have demonstrated that these combinations not only resolved the lack of mechanical strength and osteogenic effects of CPC but also further improve its own functional properties. However, exceptions were seen in CPC incorporated with certain proteins (such as elastin-like polypeptide and calcitonin gene-related peptide) as well as blood components. In conclusion, the addition of biological materials potentially improves CPC features, which vary depending on the types of materials embedded into it. The significant enhancement of CPC seen in vitro and in vivo requires further verification in human trials for its clinical application.

Effect of Hyaluronic Acid Gel on Healing of Simple Dental Extraction Sockets: A Pilot Study

BACKGROUND: Hyaluronic acid (HA) was explored as a powerful positive biocompatible material that participates in numerous biological processes related to morphogenesis and tissue healing. AIM: In this context, we elevated in this pilot study the effect of HA on soft tissue healing and bone repair of dental sockets (DS) as well as the postoperative pain. MATERIALS AND METHODS: Ten individuals of both genders (80% females and 20% males) with age range 18–44 years, were included who were diagnosed with two non-restorable teeth (total sockets n = 20). A split-mouth study design was performed where the DS of each patient were divided into Group A (study group): Topical oral HA gel (Gengigel®) was applied into sockets while Group B (control group): Sockets were left untreated. Study variables were evaluated including socket length, socket healing scores (healing index), and post-operative pain in both groups at day 1, 5, and 10 for each patient. RESULTS: There were no statistically significant differences between the control and study groups regarding the reduction of the socket length and postoperative complications but results revealed that HA enhances and fasten the healing capacity. CONCLUSION: HA can be used as adjunctive treatment to improve the wound healing process.