Hyaluronic acid with antioxidants improve wound healing in rats

Enhancing wound healing with synthetic hyaluronic acid injection in sutured incisions on BALB/c mice

INTRODUCTION

Hyaluronic acid has been shown to possess notable properties in wound healing, skin regeneration, and anti-inflammatory effects. The formation of scar tissue is a common and unintended phenomenon during the wound-healing process, potentially leading to diverse consequences for individuals.

Hyaluronan Tetrasaccharides Penetrate into the Skin by Passive Diffusion and Contribute to Skin Health

Hyaluronan (HA) is a commonly used material in cosmetics and pharmaceuticals because of its various pharmacological activities. However, because of its large molecular weight, HA penetrates the skin very poorly and most of it remains on the skin surface. Thus, topically applied HA could not be expected to function biologically in the skin. However, we have confirmed that HA tetrasaccharides (HA4), which is the smallest unit of HA, penetrate into the skin by passive diffusion and affect epidermal metabolism. Topical treatment of HA4 rescues the epidermal damage caused by long-term UVA irradiation. Furthermore, various biological functions of HA4 to maintain healthy skin was observed in cell culture studies. This review describes the skin permeability of HA4 and how it contributes to healthy skin.

Lidocaine-Loaded Thermoresponsive Gel for Accelerated Wound Healing in Dry Socket and Oral Wounds

Dry socket, also known as alveolar osteitis, presents significant challenges in oral surgery because of severe pain and delayed wound healing. This study aims to address these challenges by developing and evaluating a lidocaine-loaded polyelectrolyte complex thermoresponsive gel (LG) designed to enhance wound healing and provide effective pain management in oral wounds. The thermoresponsive gel transitions from a liquid to a gel at body temperature, ensuring sustained contact with the wound site and prolonged release of lidocaine. The in vitro assessments, including cytotoxicity and wound scratch assays, demonstrated the biocompatibility and therapeutic potential of the LG formulation. Following this, palatal wounds were induced in rats, with healing monitored over a 14-days period. Histological analyses were conducted to assess tissue regeneration and inflammation. The results indicated that the LG formulation significantly improved wound closure rates, reduced inflammation, and accelerated epithelialization compared with control groups, primarily because of the high content of hyaluronic acid (HA). The synergistic effects of HA combined with the thermoresponsive properties of the gel facilitated faster healing. These findings suggest that LG is a promising therapeutic option for enhancing oral wound healing and effectively managing pain, particularly in conditions such as dry socket.

Tailoring biomaterials for skin anti-aging

Skin aging is the phenomenon of degenerative changes in the structure and function of skin tissues over time and is manifested by a gradual loss of skin elasticity and firmness, an increased number of wrinkles, and hyperpigmentation. Skin anti-aging refers to a reduction in the skin aging phenomenon through medical cosmetic technologies. In recent years, new biomaterials have been continuously developed for improving the appearance of the skin through mechanical tissue filling, regulating collagen synthesis and degradation, inhibiting pigmentation, and repairing the skin barrier. This review summarizes the mechanisms associated with skin aging, describes the biomaterials that are commonly used in medical aesthetics and their possible modes of action, and discusses the application strategies of biomaterials in this area. Moreover, the synergistic effects of such biomaterials and other active ingredients, such as stem cells, exosomes, growth factors, and antioxidants, on tissue regeneration and anti-aging are evaluated. Finally, the possible challenges and development prospects of biomaterials in the field of anti-aging are discussed, and novel ideas for future innovations in this area are summarized.

Effect of orodispersible hyaluronic acid film on palatal mucosa wound healing

OBJECTIVE

The objective of the study was to evaluate the healing effect of hyaluronic acid films on palatal wounds.

MATERIALS AND METHODS

After making 5-mm diameter palatal wounds, 72 rats were randomly assigned to three groups: control, hyaluronic acid gel, and hyaluronic acid film. The animals were sacrificed at 3, 7, and 21 days after the experiment. Clinical, histological, and RT-PCR analyses were performed. Human ex vivo oral mucosa models were used. Histological analysis and pan-cytokeratin staining were performed at 5 days after wound creation.

RESULTS

In rat model, both gels and films showed favorable healing on Days 3 and 7 compared with healing in the control (p < 0.05). Film showed remarkable VEGF and α-SMA expression than did the others (p < 0.05). Immunohistochemical analysis showed that film exhibited significantly lower CD68 and greater α-SMA and vimentin expression levels than those in the others (p < 0.05). In human model, re-epithelialization rate of film group was significantly higher than that of the others. Complete epithelial regeneration was confirmed only in film group using pan-cytokeratin staining.

CONCLUSIONS

Within the limits of this study, hyaluronic acid film outperformed gels in terms of palatal wound healing in both models.

Unique combination of hyaluronic acid and amino acids in the management of patients with a range of moderate-to-severe chronic wounds: Evidence from international clinical trials

Chronic wounds present a prolonged burden to patients, their families and healthcare systems. There is evidence that the unique combination of hyaluronic acid (HA) and amino acids (Vulnamin®) promotes re-epithelialization of wounds and stimulates activation and proliferation of fibroblasts with a significant increase in the regeneration of epithelial cells. Tissue regeneration and tissue repair are considered to be the fundamental activities of this unique combination of HA and amino acids that distinguishes it from other wound healing products. A review of trials over the last 15 years indicates distinct advantages of the unique combination of HA and amino acids, in terms of healing rate and induction of granulation tissue production compared with HA alone.

Synthesis and Characterization of a Biopolymer Pectin/Ethanolic Extract from Olive Mill Wastewater: In Vitro Safety and Efficacy Tests on Skin Wound Healing

Wound-healing delay is one of the major problems of type 2 diabetes, representing also a clinical emergency in non-healing chronic wounds. Natural antioxidants show interesting wound-healing properties, including those extracted from waste derived from olive oil production. Olive mill wastewater is one of the main by-products of the olive oil-making process, and it is rich in high-value secondary metabolites, mainly hydroxytyrosol. We proposed an eco-friendly extraction method, employing both ultrasound-assisted and Soxhlet techniques and ethanol as a solvent, to recover valuable molecules from Roggianella cv (Olea europea L.) olive mill wastewater, which was further entrapped in a pectin polymer via an enzymatic reaction using porcine pancreatic lipase. Pectin, in combination with other substances, promoted and accelerated wound healing and demonstrated good potential to produce a biomedical conjugate for wound treatment. The antioxidant activity of the extracts and conjugate were evaluated against lipophilic (IC50 equal to 0.152 mg mL-1) and hydrophilic (IC50 equal to 0.0371 mg mL-1) radical species as well as the in vitro cytotoxicity via NRU, h-CLAT, and a wound-healing scratch assay and assessment. The pectin conjugate did not exert hemolytic effects on the peripheral blood, demonstrating interesting wound-healing properties due to its ability to stimulate cell proliferation in a dose-dependent manner.

Comparison of hyaluronic acid, hypochlorous acid, and flurbiprofen on postoperative morbidity in palatal donor area: a randomized controlled clinical trial

OBJECTIVE

This study aims to evaluate the effects of topical hyaluronic acid (HA), hypochlorous acid (HOCl), and flurbiprofen on postoperative morbidity of palatal donor sites after free gingival graft (FGG) surgery.

MATERIALS AND METHODS

Sixty patients requiring FGG were randomly assigned into four groups: control, HA gel (600 mg/100 g high molecular weight hyaluronic acid), HOCl spray (170-200 ppm, ph7.1), flurbiprofen spray (0.075gr flurbiprofen). Topical agents were applied for 14 days, according to groups. Patients were followed for 28 days. Palatal healing was assessed with the Laundry wound healing index (WHI). Complete epithelization (CE) was evaluated with photographs and H₂O₂ bubbling. Pain, burning sensation, chewing efficacy, and tissue color match (CM) were evaluated using a visual analog scale (VAS). Postoperative analgesic consumption and delayed bleeding (DB) were also recorded.

RESULTS

HA provided better WHI values on the 7^th, 14^th, and 21^st days compared to the other groups, respectively (p < 0.05). CE was formed on the 21^st day in the HA group but on the 28^th day in the other groups. HOCl and flurbiprofen groups were not different from the control group or each other in terms of WHI. HOCl had the lowest VAS scores of all time periods. DB was not observed in any group. Significantly fewer analgesics were taken in the topical agent-applied groups compared to the control group.

CONCLUSIONS

HA exhibits a positive impact on the epithelization of palatal wound healing and color matching. HOCl and flurbiprofen provided less pain; however, they might have negative effects on palatal wound healing.

CLINICAL RELEVANCE

As a result of obtaining free gingival grafts from palatal tissue for mucogingival surgical procedures, secondary wound healing of the donor area occurs. This wound in the palatal region can cause discomfort and pain every time patients use their mouths. The use of HA can reduce postoperative complications by accelerating wound healing and reducing pain. The topical use of flurbiprofen and HOCl can reduce patients' pain.

Drug Release and Cytotoxicity of Hyaluronic Acid and Zinc Oxide Gels, An In-Vitro Study

Hyaluronic acid (HA) is a naturally occurring biopolymer, with a remarkable wound healing property. Zinc-oxide non-eugenol is a material widely used for periodontal dressing in dentistry. However, it has been reported that zinc oxide non-eugenol is toxic to osteoblasts and fibroblasts. Hence, the present study aimed to evaluate the drug release and cytotoxicity of HA and zinc-oxide gels. Hydrogels of HA and zinc oxide were formulated with carbopol as a carrier. In vitro drug release was performed by UV spectrophotometry, dialysis, and vial bag methods. Cytotoxicity assessment of HA and zinc-oxide gels was performed in human periodontal ligament fibroblasts (HPdLF) and human gingival fibroblasts (hGFs). An inverted phase-contrast microscope was used to assess the morphological changes. At 24 and 48 hr, HPdLF cells showed the highest viability in 0.1% low molecular weight-HA (LMW-HA) with a median value of 131.9, and hGFs showed the highest viability in 5% LMW-HA with a median of 129.56. The highest viability of HPdLF cells was observed in 5% high molecular weight-HA (HMW-HA), with a median value of 127.11. hGFs showed the highest viability in 1% HMW-HA with a median value of 97.99. Within the limitations of the present study, we concluded that LMW-HA is more efficient than HMW-HA. Both HPdLF and hGF cells showed complete cell morbidity with zinc-oxide hydrogels. Therefore, zinc oxide-based gels in concentrations as low as 9% could be toxic intraorally to soft tissues that harbor gingival and periodontal ligament fibroblasts.

The Impact of Corticosteroid Administration at Different Time Points on Mucosal Wound Healing in Rats: An Experimental Pilot In Vivo Study

Simple Summary

The objective of this pilot study was to evaluate the impact of corticosteroid (CS) administration at different time points on palatal wound healing in rats. Thirty-six young male rats were divided into three groups. The test groups were treated by CS in the early (1–4 days) and late (5–9 days) stages after palatal wounding, while the control group was left for spontaneous healing. Our findings do not support the positive impact of CS administration on palatal wound healing. While microscopically, we found no difference between the CS and control groups, CS exposure was associated with a macroscopically larger final wound area, reflecting a possible harmful effect of CS.

Abstract

Background: Conflicting results were found regarding the effect of corticosteroid (CS) administration upon wound healing. The objective of this pilot study was to evaluate the impact of CS administration at different time points on palatal wound healing in rats. Methods: A 4.2 mm diameter punch created a secondary healing excisional palatal defect in thirty-six (36) Wistar-derived, two-month-old male rats weighing 250–270 g. We evaluated the effect of CS by comparing wound healing between three equal groups: 12 rats who were not exposed to CS and two additional groups in which 1 mg/kg dexamethasone (1 mg/kg) was administered daily, early (1–4 days) and late (5–9 days) after injury. The dynamics of the healing process were evaluated weekly in 4 sacrificed rats from each group for three weeks. The wound area was assessed both macroscopically and microscopically; the inflammation score was assessed microscopically. Results: The initial wound area in all the rats was 13.85 mm². At the end of the study, it decreased to 4.11 ± 0.88 mm², 7.32 ± 2.11 mm², and 8.87 ± 3.01 mm² in control, early, and late CS administration groups, respectively (p = 0.075). Inflammation scores showed a tendency to decrease in the third week in all groups, with no statistical differences. Conclusions: Our findings do not support the positive impact of CS administration on palatal wound healing. While microscopically, we found no difference between the CS and control groups, CS exposure was associated with a macroscopically larger final wound area, reflecting a possible harmful effect of CS.

Natural Biopolymers as Additional Tools for Cell Microencapsulation Applied to Cellular Therapy

One of the limitations in organ, tissue or cellular transplantations is graft rejection. To minimize or prevent this, recipients must make use of immunosuppressive drugs (IS) throughout their entire lives. However, its continuous use generally causes several side effects. Although some IS dose reductions and withdrawal strategies have been employed, many patients do not adapt to these protocols and must return to conventional IS use. Therefore, many studies have been carried out to offer treatments that may avoid IS administration in the long term. A promising strategy is cellular microencapsulation. The possibility of microencapsulating cells originates from the opportunity to use biomaterials that mimic the extracellular matrix. This matrix acts as a support for cell adhesion and the syntheses of new extracellular matrix self-components followed by cell growth and survival. Furthermore, by involving the cells in a polymeric matrix, the matrix acts as an immunoprotective barrier, protecting cells against the recipient’s immune system while still allowing essential cell survival molecules to diffuse bilaterally through the polymer matrix pores. In addition, this matrix can be associated with IS, thus diminishing systemic side effects. In this context, this review will address the natural biomaterials currently in use and their importance in cell therapy.

Hyaluronan as a Prominent Biomolecule with Numerous Applications in Medicine

Hyaluronan (HA) is a natural glycosaminoglycan present in many tissues of all vertebrates. HA has various biological functions, which are dependent on its molar mass. High-molar-mass HA has anti-angiogenic, immunosuppressive and anti-inflammatory properties, while low-molar-mass HA has opposite effects. HA has also antioxidative properties, however on the other hand it can be readily degraded by reactive oxygen species. For many years it has been used in treatment of osteoarthritis, cosmetics and in ophthalmology. In the last years there has been a growing interest of HA to also be applied in other fields of medicine such as skin wound healing, tissue engineering, dentistry and gene delivery. In this review we summarize information on modes of HA administration, properties and effects of HA in various fields of medicine including recent progress in the investigation of HA.