Evaluation of chitosan gel containing liposome-loaded epidermal growth factor on burn wound healing

Lipid-based nanosystems for wound healing

INTRODUCTION

Wounds, resulting from traumas, surgery, burns or diabetes, are an important medical problem, especially considering that wound healing is a complex process in term of healing times and high healthcare costs. Nanosystems have emerged as promising candidates in this field due to their properties and versatile applications in drugs delivery.

AREAS COVERED

Vesicular or particulate lipid-based nanosystems are described for wound treatment, highlighting their different behaviors when interacting with the cutaneous tissue. The role of nanosystems in delivering mostly natural compounds on skin as well as the technological and engineering strategies to increase their efficiency in wound healing effect are reviewed. Finally, in vitro, ex-vivo and in vivo studies are reported.

EXPERT OPINION

LBN have shown promise in addressing the challenges of wound healing as they can improve the stability of drugs used in wound therapy, leading to higher efficacy and fewer adverse effects as compared to traditional formulations. LBNs being involved in the inflammatory and proliferation stages of the wound healing process, enable the modification of wound healing through multiple ways. In addition, the use of new technologies, including 3D bioprinting and photobiomodulation, may lead to potential breakthroughs in wound healing. This would provide clinicians with more potent forms of therapy for wound healing.

Transdermal Delivery of Recombinant Human Growth Hormone by Liposomal Gel for Skin Photoaging Therapy

Human growth hormone (hGH) has emerged as a promising therapeutic agent to prevent and treat skin photoaging. However, the success of hGH therapy largely lies in the availability of an optimal delivery system that enables the efficient delivery of hGH to the dermal layer of the skin. Here, we report a delivery system of hyaluronic acid/liposome-gel-encapsulated hGH (HA/HL-Gel) that can transdermally deliver hGH into the skin for hGH-based photoaging therapy through the upregulation of collagen type I (collagen-I). Specifically, hGH-liposomes were prepared by ethanol injection and then modified with HA to achieve specific targeting. The best formulation of HA/hGH-liposomes (HA/HL) had a high encapsulation efficiency (about 20%), with a size of 180 ± 1.2 nm. The optimized HA/HL was further incorporated into the carbomer gel to form an HA/HL-Gel. The biological activity of HA/HL on human dermal fibroblasts (HDFs) was confirmed by the elevated expression level of collagen-I through the enhanced local formation of insulin-like growth factor-1 (IGF-1) in the photoaging model. Moreover, HA/HL-Gel reduced ultraviolet (UV)-induced erythema and wrinkle formation. Meanwhile, immunohistochemical staining further showed higher levels of collagen-I in the HA/HL-Gel group compared to other groups tested. Taken together, these results demonstrate that HA/HL-Gel treatment could significantly ameliorate skin photoaging and thus may be used as a clinical potential for antiaging therapy.

Biomaterials-Based Strategies to Enhance Angiogenesis in Diabetic Wound Healing

Amidst the present healthcare issues, diabetes is unique as an emerging class of affliction with chronicity in a majority of the population. To check and control its effects, there have been huge turnover and constant development of management strategies, and though a bigger part of the health care area is involved in achieving its control and the related issues such as the effect of diabetes on wound healing and care and many of the works have reached certain successful outcomes, still there is a huge lack in managing it, with maximum effect yet to be attained. Studying pathophysiology and involvement of various treatment options, such as tissue engineering, application of hydrogels, drug delivery methods, and enhancing angiogenesis, are at constantly developing stages either direct or indirect. In this review, we have gathered a wide field of information and different new therapeutic methods and targets for the scientific community, paving the way toward more settled ideas and research advances to cure diabetic wounds and manage their outcomes.

The Effect of Mesenchymal Stem Cells on the Wound Infection

Wound infection often requires a long period of care and an onerous treatment process. Also, the rich environment makes the wound an ideal niche for microbial growth. Stable structures, like biofilm, and drug-resistant strains cause a delay in the healing process, which has become one of the important challenges in wound treatment. Many studies have focused on alternative methods to deal the wound infections. One of the novel and highly potential ways is mesenchymal stromal cells (MSCs). MSCs are mesoderm-derived pluripotent adult stem cells with the capacity for self-renewal, multidirectional differentiation, and immunological control. Also, MSCs have anti-inflammatory and antiapoptotic effects. MScs, as pluripotent stromal cells, differentiate into many mature cells. Also, MSCs produce antimicrobial compounds, such as antimicrobial peptides (AMP), as well as secrete immune modulators, which are two basic features considered in wound healing. Despite the advantages, preserving the structure and activity of MSCs is considered one of the most important points in the treatment. MSCs' antimicrobial effects on microorganisms involved in wound infection have been confirmed in various studies. In this review, we aimed to discuss the antimicrobial and therapeutic applications of MSCs in the infected wound healing processes.

Gintonin-Induced Wound-Healing-Related Responses Involve Epidermal-Growth-Factor-like Effects in Keratinocytes

Epidermal growth factor (EGF) receptor activation and related downstream signaling pathways are known to be one of the major mechanisms of the proliferation and migration of keratinocytes. The heparin-binding EGF-like growth factor (HB-EGF) binds to EGF receptors and stimulates keratinocyte proliferation and migration. Gintonin, a novel ginseng compound, is a lysophosphatidic acid (LPA) receptor ligand. Gintonin has skin-wound-healing effects. However, the underlying mechanisms for these gintonin actions remain unclear. In this study, we aimed to elucidate the involvement of EGFRs in gintonin-induced wound repair in HaCaT keratinocytes. In this study, a water-soluble tetrazolium salt-based assay, a modified Boyden chamber migration assay, and immunoblotting were performed. Gintonin increased EGF receptor activation in HaCaT cells. However, the gintonin-induced phosphorylation of the EGF receptor was markedly reduced via treatment with the LPA inhibitor Ki16425 or the EGF receptor inhibitor erlotinib. Gintonin-enhanced proliferation and migration were blocked by the EGF receptor inhibitors (erlotinib and AG1478). Additionally, gintonin stimulated the expression and release of HB-EGF in HaCaT cells. EGF receptor inhibitors blocked gintonin-enhanced HB-EGF expression. These results indicate that the wound-healing effects of gintonin are closely related to the collaboration between EGF receptor activation and HB-EGF release-mediated downstream signaling pathways.

EGF, a veteran of wound healing: highlights on its mode of action, clinical applications with focus on wound treatment, and recent drug delivery strategies

Epidermal growth factor (EGF) has been used in wound management and regenerative medicine since the late 1980s. It has been widely utilized for a long time and still is because of its excellent tolerability and efficacy. EGF has many applications in tissue engineering, cancer therapy, lung diseases, gastric ulcers, and wound healing. Nevertheless, its in vivo and during storage stability is a primary concern. This review focuses on the topical use of EGF, especially in chronic wound healing, the emerging use of biomaterials to deliver it, and future research possibilities. To successfully deliver EGF to wounds, a delivery system that is proteolytically resistant and stable over the long term is required. Biomaterials are an area of interest for the development of such systems. These systems may be used in non-healing wounds such as diabetic foot ulcers, pressure ulcers, and burns. In these pathologies, EGF can reduce the risk of amputation of the lower extremities, as it accelerates the wound healing process. Furthermore, appropriate delivery system would also stabilize and control the EGF release profile in a wound. Several in vitro and in vivo studies have already proven the efficacy of such systems in the above-mentioned types of wounds. Moreover, several formulations such as ointments and intralesional injections are already available on the market. However, these products are still problematic in terms of inadequate diffusion of EGF, low bioavailability storage conditions, and shelf-life. This review discusses the nano formulations comprising biomaterials infused with EGF which could be a promising delivery system for chronic wound healing in the future.

Polysaccharide-based hydrogels for drug delivery and wound management: a review

INTRODUCTION

Polysaccharide-based hydrogels (PBHs) offer several advantages over their synthetic counterparts. Their natural origin contributes to their nontoxicity, high biocompatibility, and in vivo biodegradability. Their properties can be tuned finely to obtain hydrogels with desired mechanical, structural, and chemical properties.

AREAS COVERED

Such versatile characteristics have potentiated the use of PBHs for the delivery of drugs, vaccines, protein and peptide therapeutics, genes, cells, probiotics, bacteriophages, and other therapeutic agents. Recent advances in hydrogel-based formulations such as nanogels, microgels, microneedles, hydrogel beads, nanocarrier-loaded hydrogels, and complexation hydrogels have enabled the precise delivery of a wide range of therapeutics. This review aims to give a holistic overview of hydrogels in the delivery of a variety of therapeutics through different routes.

EXPERT OPINION

PBHs have been used to enable the oral delivery of vaccines and other biologicals, thereby allowing self-administration of life-saving vaccines during public health emergencies. There is a lack of commercialized wound dressings for the treatment of chronic wounds. PBH-based wound dressings, especially those based on chitosan and loaded with actives and growth factors, have the potential to help in the long-term treatment of such wounds. Recent developments in the 3D printing of hydrogels can enable the quick and large-scale production of drug-loaded hydrogels.

Novel strategies for designing regenerative skin products for accelerated wound healing

Healthy skin protects from pathogens, water loss, ultraviolet rays, and also maintains homeostasis conditions along with sensory perceptions in normal circumstances. Skin wound healing mechanism is a multi-phased biodynamic process that ultimately triggers intercellular and intracellular mechanisms. Failure to implement the normal and effective healing process may result in chronic injuries and aberrant scarring. Chronic wounds lead to substantial rising healthcare expenditure, and innovative methods to diagnose and control severe consequences are urgently needed. Skin tissue engineering (STE) has achieved several therapeutic accomplishments during the last few decades, demonstrating tremendous development. The engineered skin substitutes provide instant coverage for extensive wounds and facilitate the prevention of microbial infections and fluid loss; furthermore, they help in fighting inflammation and allow rapid neo-tissue formation. The current review primarily focused on the wound recovery and restoration process and the current conditions of STE with various advancements and complexities associated with different strategies such as cell sources, biopolymers, innovative fabrication techniques, and growth factors delivery systems.

A Narrative Review of the Potential Roles of Lipid-Based Vesicles (Vesiculosomes) in Burn Management

Burn injuries can have a lasting effect on people’s quality of life, as they negatively impact their physical and mental health. Then, they are likely to suffer psychological problems as a result. A serious problem is that deep burns are more challenging to treat due to their slow healing rate and susceptibility to microbial infection. Conventional topical medications used for burn treatment are sometimes ineffective because they cannot optimize their ability of transcutaneous absorption at the targeted site and accelerate healing. However, nanotechnology offers excellent prospects for developing current medical wound therapies and is capable of addressing issues such as low drug stability, water solubility, permeability, and bioavailability. The current review focuses on lipid-based vesicles (vesiculosomes) as an example of advanced delivery systems, showing their potential clinical applications in burn wound management. Vesiculosomes may help overcome impediments including the low bioavailability of active agents, offering the controlled release of drugs, increased drug stability, fewer side effects, and reduced dosing frequency, which will ultimately improve therapeutic efficacy and patient compliance. We discuss the application of various types of vesiculosomes such as liposomes, niosomes, ethosomes, cubosomes, transfersomes, and phytosomes in burn healing therapy, as these demonstrate superior skin penetration compared to conventional burn topical treatment. We also highlight their noteworthy uses in the formulation of natural products and discuss the current status as well as future perspectives of these carriers in burn management. Furthermore, the burn treatment options currently available in the market are also summarized.

Nanomaterials-based drug delivery approaches for wound healing

Abstract:

Wound healing is a complex and dynamic process that requires intricate synchronization between multiple cell types within appropriate extracellular microenvironment. Wound healing process involves four overlapping phases in a precisely regulated manner, consisting of hemostasis, inflammation, proliferation, and maturation. For an effective wound healing all four phases must follow in a sequential pattern within a time frame. Several factors might interfere with one or more of these phases in healing process, thus causing improper or impaired wound healing resulting in non-healing chronic wounds. The complications associated with chronic non-healing wounds, along with the limitations of existing wound therapies, have led to the development and emergence of novel and innovative therapeutic interventions. Nanotechnology presents unique and alternative approaches to accelerate the healing of chronic wounds by the interaction of nanomaterials during different phases of wound healing. This review focuses on recent innovative nanotechnology-based strategies for wound healing and tissue regeneration based on nanomaterials, including nanoparticles, nanocomposites and scaffolds. The efficacy of the intrinsic therapeutic potential of nanomaterials (including silver, gold, zinc oxide, copper, cerium oxide, etc.) and the ability of nanomaterials as carriers (liposomes, hydrogels, polymeric nanomaterials, nanofibers) as therapeutic agents associated with wound-healing applications have also been addressed. The significance of these nanomaterial-based therapeutic interventions for wound healing needs to be highlighted to engage researchers and clinicians towards this new and exciting area of bio-nanoscience. We believe that these recent developments will offer researchers an updated source on the use of nanomaterials as an advanced approach to improve wound healing.

A modified burn comb model with a new dorsal frame that allows for local treatment in partial-thickness burns in rats

Burn wound progression (BWP) leads to vertical and horizontal injury extension. The "burn comb model" is commonly used, in which a full-thickness burn with intercalated unburned interspaces is induced. We aimed to establish an injury progressing to the intermediate dermis, allowing repeated wound evaluation. Furthermore, we present a new dorsal frame that enables topical drug application. 8 burn field and 6 interspaces were induced on each of 17 rats' dorsa with a 10-second burn comb application. A developed 8-panel aluminum frame was sutured onto 12 animals and combined with an Elizabethan collar. Over 14 days, macroscopic & histologic wound assessment and Laser-Speckle-Contrast-Imaging (LSCI) were performed besides evaluation of frame durability. The 10-second group was compared to 9 animals injured with a full-thickness 60-second model. Frame durability was sufficient up to day 4 with 8 of 12 frames (67%) still mounted. The 60-second burn led to an increased extent of interspace necrosis (p=0.002). The extent of necrosis increased between days 1 and 2 (p=0.001), following the 10-second burn (24%±SEM 8% to 40%±SEM 6%) and the 60-second burn (57%±SEM 6% to 76%±SEM 4%). Interspace LSCI perfusion was higher than burn field perfusion. It earlier reached baseline levels in the 10-second group (on day 1: 142%±SEM 9% vs. 60%±SEM 5%; p<0.001). Within day 1, the 10-second burn showed histological progression to the intermediate dermis, both in interspaces and burn fields. This burn comb model with its newly developed fixed dorsal frame allows investigation of topical agents to treat BWP in partial-thickness burns.

Chitosan hydrogels incorporating colloids for sustained drug delivery

In today's biomedical research, a huge effort is being made towards the development of efficient drug delivery systems, achieving sustainable and controlled delivery of drugs. Chitosan (CS) hydrogels are high water content materials with very relevant biological properties to that purpose. Their use for a local and delayed delivery has already been demonstrated for a wide variety of therapeutic agents. One relatively recent strategy to improve these CS-based systems consists in the insertion of colloids, embedding drugs, within their three-dimensional matrix. This provides a second barrier to the diffusion of drugs through the system, and allows to better control their release. The main objective of this review is to report the many existing complex systems composed of CS hydrogels embedding different types of colloids used as drug delivery devices to delay the release of drugs. The various biomedical applications of such final systems are also detailed in this review.

Antimicrobial and Regenerative Effects of Placental Multipotent Mesenchymal Stromal Cell Secretome-Based Chitosan Gel on Infected Burns in Rats

Background: There is a need for better strategies to promote burn wound healing and prevent infection. The aim of our study was to develop an easy-to-use placental multipotent mesenchymal stromal cell (MMSC) secretome-based chitosan hydrogel (MSC-Ch-gel) and estimate its antimicrobial and regenerative activity in Staphylococcus aureus-infected burn wounds in rats. Methods: Proteomic studies of the MMSC secretome revealed proteins involved in regeneration, angiogenesis, and defence responses. The MMSC secretome was collected from cultured cells and mixed with water-soluble chitosan to prepare the placental MSC-Ch-gel, which was stored in liquid phase at 4 °C. The wounds of rats with established II-IIIa-degree burns were then infected with S. aureus and externally covered with the MSC-Ch-gel. Three additional rat groups were treated with medical Vaseline oil, the antiseptic drug Miramistin®, or the drug Bepanthen® Plus. Skin wound samples were collected 4 and 8 days after burning for further microbiological and histological analysis. Blood samples were also collected for biochemical analysis. Results: Application of the MSC-Ch-gel cleared the wound of microorganisms (S. aureus wasn’t detected in the washings from the burned areas), decreased inflammation, enhanced re-epithelialisation, and promoted the formation of well-vascularised granulation tissue. Conclusions: MSC-Ch-gel effectively promotes infected wound healing in rats with third-degree burns. Gel preparation can be easily implemented into clinical practice.

Insightful exploring of advanced nanocarriers for the topical/transdermal treatment of skin diseases

Dermatological products constitute a big segment of the pharmaceutical market. From conventional products to more advanced ones, a wide variety of dosage forms have been developed till current date. A representative of the advanced delivery means is carrier-based systems, which can load large number of drugs for treatment of dermatological diseases, or simply for cosmeceutical purposes. To make them more favorable for topical delivery, further incorporation of these carriers in a topical vehicle, such as gels or creams is made. Therefore in this review article, an overview is compiled of the most commonly encountered novel carrier based topical delivery systems; namely lipid based (nanoemulsions, microemulsions, solid lipid nanoparticles [SLNs] and nanostructured lipid carriers [NLCs]), and vesicular carriers (non-deformable, such as liposomes, niosomes, emulsomes and cerosomes, and deformable, such as transfersomes, ethosomes, transethosomes, and penetration enhancer vesicles), with special emphasis on those loaded in a secondary gel vehicle. A special focus was made on the commonly encountered dermatological diseases, such as bacterial and fungal infections, psoriasis, dermatitis, eczema, vitiligo, oxidative damage, aging, alopecia, and skin cancer.

Lipid-Based Drug Delivery Systems in Regenerative Medicine

The most important goal of regenerative medicine is to repair, restore, and regenerate tissues and organs that have been damaged as a result of an injury, congenital defect or disease, as well as reversing the aging process of the body by utilizing its natural healing potential. Regenerative medicine utilizes products of cell therapy, as well as biomedical or tissue engineering, and is a huge field for development. In regenerative medicine, stem cells and growth factor are mainly used; thus, innovative drug delivery technologies are being studied for improved delivery. Drug delivery systems offer the protection of therapeutic proteins and peptides against proteolytic degradation where controlled delivery is achievable. Similarly, the delivery systems in combination with stem cells offer improvement of cell survival, differentiation, and engraftment. The present review summarizes the significance of biomaterials in tissue engineering and the importance of colloidal drug delivery systems in providing cells with a local environment that enables them to proliferate and differentiate efficiently, resulting in successful tissue regeneration.

Film-Forming Spray of Water-Soluble Chitosan Containing Liposome-Coated Human Epidermal Growth Factor for Wound Healing

Human epidermal growth factor (hEGF) has been known to have excellent wound-healing activity. However, direct application to the wound area can lead to low hEGF bioavailability due to protease enzymes or endocytosis. The use of liposomes as coatings and carriers can protect hEGF from degradation by enzymes, chemical reactions, and immune reactions. Sustained release using a matrix polymer can also keep the levels of hEGF in line with the treatment. Therefore, this study aimed to develop a film-forming spray of water-soluble chitosan (FFSWSC) containing hEGF-liposomes as a potential wound dressing. The hEGF-liposomes were prepared using the hydration film method, and the preparation of the FFSWSC was achieved by the ionic gelation method. The hydration film method produced hEGF-liposomes that were round and spread with a Z-average of 219.3 nm and encapsulation efficiency of 99.87%, whereas the film-forming solution, which provided good sprayability, had a formula containing 2% WSC and 3% propylene glycol with a viscosity, spray angle, droplet size, spray weight, and occlusion factor of 21.94 ± 0.05 mPa.s, 73.03 ± 1.28°, 54.25 ± 13.33 µm, 0.14 ± 0.00 g, and 14.57 ± 3.41%, respectively. The pH, viscosity, and particle size of the FFSWSC containing hEGF-liposomes were stable during storage for a month in a climatic chamber (40 ± 2 °C, RH 75 ± 5%). A wound healing activity test on mice revealed that hEGF-liposomes in FFSWSC accelerated wound closure significantly, with a complete wound closure on day 6. Based on the findings, we concluded that FFSWSC containing hEGF-liposomes has the potential to be used as a wound dressing.

Chitosan-microencapsulated rhEGF in promoting wound healing

AIMS

Chitosan and epidermal growth factor (EGF) have been shown to improve wound healing. This study investigates the healing effects of a spray solution (NewEpi, JoyCom Bio-Chem Co. Ltd., Taiwan) containing recombinant human EGF (rhEGF) delivered via a newly patented technology-chitosan microencapsulated nanoparticles.

METHODS

On Wistar rats, two full-thickness wounds on the dorsum bilateral of the spine were created. The rats were randomised to the following treatment groups: hydrogel, wet dressing, foam, rhEGF spray and rhEGF spray+foam. Sterile dressings were applied and changed daily. A total of 2μg of rhEGF was administered in two sprays during each dressing change. All animals were euthanised on day 14. Tissue samples were taken from the wound bed, including an area of 2cm surrounding the wound margin for histological evaluations.

RESULTS

Wounds treated with the rhEGF spray achieved the greatest size reduction by day 14 compared with other types of conventional dressings. An overall significant difference in levels of collagen synthesis existed between groups (p<0.01). Pair-wise comparisons showed that the rhEGF spray treatment significantly promoted higher levels of mature Type I collagen than any other conventional dressings (p<0.01), whereas non-rhEGF treatments resulted in higher levels of Type III collagen. The regenerated tissue in rhEGF spray treatment groups was also in alignment with that of normal skin. Epidermis, dermis and hair follicles were easily observed in wounds treated with the rhEGF spray.

CONCLUSION

The major challenge of topical application of rhEGF was overcome by using a new drug delivery technology: chitosan-rhEGF nanoparticles. The positive healing effects observed in this study suggest the therapeutic potentials of this novel rhEGF topical spray solution.

Applications of Nanosized-Lipid-Based Drug Delivery Systems in Wound Care

Impaired wound healing is an encumbering public health issue that increases the demand for developing new therapies in order to minimize health costs and enhance treatment efficacy. Available conventional therapies are still unable to maximize their potential in penetrating the skin at the target site and accelerating the healing process. Nanotechnology exhibits an excellent opportunity to enrich currently available medical treatments, enhance standard care and manage wounds. It is a promising approach, able to address issues such as the permeability and bioavailability of drugs with reduced stability or low water solubility. This paper focuses on nanosized-lipid-based drug delivery systems, describing their numerous applications in managing skin wounds. We also highlight the relationship between the physicochemical characteristics of nanosized, lipid-based drug delivery systems and their impact on the wound-healing process. Different types of nanosized-lipid-based drug delivery systems, such as vesicular systems and lipid nanoparticles, demonstrated better applicability and enhanced skin penetration in wound healing therapy compared with conventional treatments. Moreover, an improved chemically and physically stable drug delivery system, with increased drug loading capacity and enhanced bioavailability, has been shown in drugs encapsulated in lipid nanoparticles. Their applications in wound care show potential for overcoming impediments, such as the inadequate bioavailability of active agents with low solubility. Future research in nanosized-lipid-based drug delivery systems will allow the achievement of increased bioavailability and better control of drug release, providing the clinician with more effective therapies for wound care.

Therapeutic effects of EGF-modified curcumin/chitosan nano-spray on wound healing

Dermal injury, including trauma, surgical incisions, and burns, remain the most prevalent socio-economical health care issue in the clinic. Nanomedicine represents a reliable administration strategy that can promote the healing of skin lesions, but the lack of effective drug delivery methods can limit its effectiveness. In this study, we developed a novel nano-drug delivery system to treat skin defects through spraying. We prepared curcumin-loaded chitosan nanoparticles modified with epidermal growth factor (EGF) to develop an aqueous EGF-modified spray (EGF@CCN) for the treatment of dermal wounds. In vitro assays showed that the EGF@CCN displayed low cytotoxicity, and that curcumin was continuously and slowly released from the EGF@CCN. In vivo efficacy on wound healing was then evaluated using full-thickness dermal defect models in Wistar rats, showing that the EGF@CCN had significant advantages in promoting wound healing. On day 12 post-operation, skin defects in the rats of the EGF@CCN group were almost completely restored. These effects were related to the activity of curcumin and EGF on skin healing, and the high compatibility of the nano formulation. We therefore conclude that the prepared nano-scaled EGF@CCN spray represents a promising strategy for the treatment of dermal wounds.

bFGF and collagen matrix hydrogel attenuates burn wound inflammation through activation of ERK and TRK pathway

Burn injuries are most challenging to manage since it causes loss of the integrity of large portions of the skin leading to major disability or even death. Over the years, hydrogels are considered as a significant delivery system for wound treatment because of several advantages over other conventional formulations. We hypothesized that the bFGF-collagen-AgSD incorporated hydrogel formulation can accelerate the rate of burn healing in animal model and would promote fibroblast cell proliferation. Neovascularization and re-epithelialization is a hall mark of burn wound healing. In the present study, histopathological investigation and scanning electron microscopy of skin tissue of Wistar rats showed almost complete epithelialisation after 16 days in the treatment group. The developed hydrogel showed significantly accelerated wound closure compared with a standard and control group. The faster wound closure resulted from increased re-epithelialization and granulation tissue formation because of the presence of collagen and growth factor. Expressions of proteins such as TrkA, p- TrkA, ERK1/2, p-ERK1/2, NF-kβ, and p-NF-kβ involved in nerve growth factor (NGF) signalling pathway were analysed by western blot. All the findings obtained from this study indicated that the hydrogel can be considered as a promising delivery system against second degree burn by faster healing.

Development of chitosan, gelatin and liposome film and analysis of its biocompatibility in vitro

A film of chitosan, gelatin and liposome has been designed for dermatological applications. Several adaptations were required throughout development to facilitate in vitro analysis, physicochemical characterization and biocompatibility evaluation. The final version of the film was characterized by differential scanning calorimetry, evaluation of swelling and scanning electron microscopy. The biocompatibility of the film was assessed by investigating cellular parameters of three types of human cells by direct contact or through films extracts: I) primary culture of adipose-derived mesenchymal stromal cells (ADCSs) and melanoma cell lines were used to test cell adhesion and morphology by direct cell culture on the material; II) ADSCs and immortalized keratinocytes were used in cell viability assay using different films extracts. The film showed physicochemical characteristics that favored cellular input, being suitable for in vitro analysis, which allowed its biocompatible characteristics such as the absence of toxicity to be verified without causing significant morphological changes in ADSCs and melanoma cell line. Altogether, these results suggest that the material has a potential application for drug delivery and promotion of skin tissue repair and is therefore worthwhile for further investigations using preclinical models to cover dermal lesions.

Nanomaterials for Wound Dressings: An Up-to-Date Overview

As wound healing continues to be a challenge for the medical field, wound management has become an essential factor for healthcare systems. Nanotechnology is a domain that could provide different new approaches concerning regenerative medicine. It is worth mentioning the importance of nanoparticles, which, when embedded in biomaterials, can induce specific properties that make them of interest in applications as materials for wound dressings. In the last years, nano research has taken steps to develop molecular engineering strategies for different self-assembling biocompatible nanoparticles. It is well-known that nanomaterials can improve burn treatment and also the delayed wound healing process. In this review, the first-line of bioactive nanomaterials-based dressing categories frequently applied in clinical practice, including semi-permeable films, semipermeable foam dressings, hydrogel dressings, hydrocolloid dressings, alginate dressings, non-adherent contact layer dressings, and multilayer dressings will be discussed. Additionally, this review will highlight the lack of high-quality evidence and the necessity for future advanced trials because current wound healing therapies generally fail to provide an excellent clinical outcome, either structurally or functionally. The use of nanomaterials in wound management represents a unique tool that can be specifically designed to closely reflect the underlying physiological processes in tissue repair.

Potential application of liposomal nanodevices for non-cancer diseases: an update on design, characterization and biopharmaceutical evaluation

Liposomes, lipid-based vesicular systems, have attracted major interest as a means to improve drug delivery to various organs and tissues in the human body. Recent literature highlights the benefits of liposomes for use as drug delivery systems, including encapsulating of both hydrophobic and hydrophilic cargos, passive and active targeting, enhanced drug bioavailability and therapeutic effects, reduced systemic side effects, improved cargo penetration into the target tissue and triggered contents release. Pioneering work of liposomes researchers led to introduction of long-circulating, ligand-targeted and triggered release liposomes, as well as, liposomes containing nucleic acids and vesicles containing combination of cargos. Altogether, these findings have led to widespread application of liposomes in a plethora of areas from cancer to conditions such as cardiovascular, neurologic, respiratory, skin, autoimmune and eye disorders. There are numerous review articles on the application of liposomes in treatment of cancer, which seems the primary focus, whereas other diseases also benefit from liposome-mediated treatments. Therefore, this article provides an illustrated detailed overview of liposomal formulations, in vitro characterization and their applications in different disorders other than cancer. Challenges and future directions, which must be considered to obtain the most benefit from applications of liposomes in these disorders, are discussed.

Evaluation of the Healing Effects of Hypericum perforatum and Curcumin on Burn Wounds in Rats

BACKGROUND

For centuries, medicinal plants have been extensively used in wound healing of burn injuries. The aim of this study is to analyze comparatively the effects of curcumin and Hypericum perforatum (HP) on second-degree burn wounds in rats. Materials and Methods. This experimental study was conducted on 24 male Sprague-Dawley rats with second-degree burns. The animals were randomly divided into three groups. The burns were treated with curcumin (Group B) and Hypericum perforatum (HP) on second-degree burn wounds in rats.

RESULTS

All histological parameters of the control group showed statistically significant difference than the other groups (p < 0.05). There was no statistically significant difference between Groups B and C in terms of reepithelization and inflammation (p < 0.05). There was no statistically significant difference between Groups B and C in terms of reepithelization and inflammation (p < 0.05). There was no statistically significant difference between Groups B and C in terms of reepithelization and inflammation (p < 0.05). There was no statistically significant difference between Groups B and C in terms of reepithelization and inflammation (.

CONCLUSION

Both curcumin and Hypericum perforatum oil are effective in burn wound healing. Our findings showed a better quality of healing in curcumin-treated rats.Hypericum perforatum (HP) on second-degree burn wounds in rats.

Healing Properties of Epidermal Growth Factor and Tocotrienol-Rich Fraction in Deep Partial-Thickness Experimental Burn Wounds

Background: An experimental study was undertaken to determine the efficacy of the epidermal growth factor (EGF) with tocotrienol-rich fraction (TRF) cream in the wound-healing process on skin with deep partial-thickness burn in rats. Methods: A total of 180 Sprague-Dawley rats were randomly divided into six groups of six each and were: untreated control, treated with Silverdin^® cream, base cream, base cream with c% EGF, base cream with 3% TRF or base cream with c% EGF and 3% TRF, respectively. Creams were applied once daily for 21 consecutive days. Six animals from each group were sacrificed using anaesthetic overdose on the third, seventh, 11th, 14th and 21st day post-burn. Skin tissues with the wound to be examined were excised for macroscopic and microscopic evaluation and biochemical analyses. Results: EGF + TRF formulation decreased the number of neutrophils, lymphocytes and myofibroblasts post-burn. However, no effects on the number of adipose cells in the healing process were recorded. In addition, lipid peroxidation and nitrite production were found to be reduced post-burn, reducing oxidative stress. Conclusions: Results of the present study indicate that the addition of EGF with TRF have ameliorating effects on deep-partial thickness burn healing parameters.

Evaluation of wound healing effect of chitosan-based gel formulation containing vitexin

Acute or chronic wounds are one of the most common health problems worldwide and medicinal drugs or traditional remedies are often used in wound healing. Further studies regarding wound treatment are rapidly continuing. Vitexin is a phenolic compound, which is found in many medicinal plants, has different pharmacological effects such as anti-inflammatory, analgesic and antioxidant. In the present study, it is aimed to investigate the wound healing effect of formulation prepared as chitosan-based gel with vitexin in vivo and in vitro. Cytotoxicity and wound healing assays were used for in vitro and excisional wound model is used for in vivo studies. Extracted tissues from wound area were histologically examined. Wound healing process was monitored on 7, 14 and 21st days. When wound construction was evaluated, chitosan-based gel formulation containing vitexin demonstrated significant effect compared to control group. Histological examinations demonstrated that skin regeneration was promoted by vitexin formulation. Significant cell proliferation was observed with vitexin/chitosan dispersion in the wound healing assay performed with NIH 3T3 and HaCaT cells. In conclusion, our test substance chitosan-based gel formulation containing vitexin significantly accelerated wound healing both in vivo and in vitro.

Nano-drug delivery systems in wound treatment and skin regeneration

Skin damages are defined as one of most common lesions people suffer from, some of wounds are notoriously difficult to eradicate such as chronic wounds and deep burns. Existing wound therapies have been proved to be inadequate and far from satisfactory. The cutting-edge nanotechnology offers an unprecedented opportunity to revolutionize and invent new therapies or boost the effectiveness of current medical treatments. In particular, the nano-drug delivery systems anchor bioactive molecules to applied area, sustain the drug release and explicitly enhance the therapeutic efficacies of drugs, thus making a fine figure in field relevant to skin regeneration. This review summarized and discussed the current nano-drug delivery systems holding pivotal potential for wound healing and skin regeneration, with a special emphasis on liposomes, polymeric nanoparticles, inorganic nanoparticles, lipid nanoparticles, nanofibrous structures and nanohydrogel.

Platelet rich plasma hydrogels promote in vitro and in vivo angiogenic potential of adipose-derived stem cells

Despite great advances in skin wound care utilizing grafting techniques, the resulting severe scarring, deformity and ineffective vascularization remains a challenge. Alternatively, tissue engineering of new skin using patient-derived stem cells and scaffolding materials promises to greatly increase the functional and aesthetic outcome of skin wound healing. This work focused on the optimization of a polyethylene glycol modified (PEGylated) platelet-rich plasma (PRP) hydrogel for the protracted release of cytokines, growth factors, and signaling molecules and also the delivery of a provisional physical framework for stem cell angiogenesis. Freshly collected whole blood was utilized to synthesize PEGylated PRP hydrogels containing platelet concentrations ranging from 0 to 200,000 platelets/µl. Hydrogels were characterized using thromboelastography and impedance aggregometry for platelet function and were visualized using scanning electron microscopy. To assess the effects of PEGylated PRP hydrogels on cells, PRP solutions were seeded with human adipose-derived stem cells (ASCs) prior to gelation. Following 14 days of incubation in vitro, increased platelet concentrations resulted in higher ASC proliferation and vascular gene and protein expression (assessed via RT-PCR, ELISA, and immunochemistry). Using a rat skin excision model, wounds treated with PRP + ASC hydrogels increased the number of vessels in the wound by day 8 (80.2 vs. 62.6 vessels/mm²) compared to controls. In conclusion, the proposed PEGylated PRP hydrogel promoted both in vitro and transient in vivo angiogenesis of ASCs for improved wound healing. STATEMENT OF SIGNIFICANCE: Our findings support an innovative means of cellular therapy intervention to improve surgical wound healing in a normal wound model. ASCs seeded within PEGylated PRP could be an efficacious and completely autologous therapy for treating patients who have poorly healing wounds caused by vascular insufficiency, previous irradiation, or full-thickness burns. Because wound healing is a dynamic and complex process, the application of more than one growth factor with ASCs demonstrates an advantageous way of improving healing.

A dual deformable liposomal ointment functionalized with retinoic acid and epidermal growth factor for enhanced burn wound healing therapy

A dual deformable liposomal ointment functionalized with TRA and EGF remarkably promoting wound healing.

Optimization and Characterization of Thymoquinone-Loaded Liposomes with Enhanced Topical Anti-inflammatory Activity

Thymoquinone, the major constituent of Nigella sativa oil has been found to have a promising topical anti-inflammatory activity; however, exaggerated heat and photo-sensitivity and lipophilicity prevent the best use of this promising product. The present work aimed to formulate an ideal thymoquinone liposomal system for topical delivery. Different liposomal systems were developed using thin film hydration method by applying different cholesterol molar concentrations, different total lipid molar concentrations, and different drug-to-lipid ratios. Morphological characterization of the prepared formulae was performed using polarized light, scanning electron microscope, and transmission electron microscope. The optimized formula (F12) was selected on the basis of enhanced permeation through the skin and was incorporated into chitosan gel for topical application. The gel formulation was clear with suitable skin permeation and exhibited acceptable rheological properties. Using carrageenan-induced paw edema in rats, the developed chitosan gel (F12) showed significant superior in vivo anti-inflammatory activity over the chitosan gel of the TQ (p < 0.05) and comparable effect to the marketed indomethacin gel. As a conclusion, results revealed the potential of formulating thymoquinone as liposomal formulation in enhancing the anti-inflammatory effect compared to the TQ solution.

Advancements in Regenerative Strategies Through the Continuum of Burn Care

Burns are caused by several mechanisms including flame, scald, chemical, electrical, and ionizing and non-ionizing radiation. Approximately half a million burn cases are registered annually, of which 40 thousand patients are hospitalized and receive definitive treatment. Burn care is very resource intensive as the treatment regimens and length of hospitalization are substantial. Burn wounds are classified based on depth as superficial (first degree), partial-thickness (second degree), or full-thickness (third degree), which determines the treatment necessary for successful healing. The goal of burn wound care is to fully restore the barrier function of the tissue as quickly as possible while minimizing infection, scarring, and contracture. The aim of this review is to highlight how tissue engineering and regenerative medicine strategies are being used to address the unique challenges of burn wound healing and define the current gaps in care for both partial- and full-thickness burn injuries. This review will present the current standard of care (SOC) and provide information on various treatment options that have been tested pre-clinically or are currently in clinical trials. Due to the complexity of burn wound healing compared to other skin injuries, burn specific treatment regimens must be developed. Recently, tissue engineering and regenerative medicine strategies have been developed to improve skin regeneration that can restore normal skin physiology and limit adverse outcomes, such as infection, delayed re-epithelialization, and scarring. Our emphasis will be centered on how current clinical and pre-clinical research of pharmacological agents, biomaterials, and cellular-based therapies can be applied throughout the continuum of burn care by targeting the stages of wound healing: hemostasis, inflammation, cell proliferation, and matrix remodeling.

Drug delivery and tissue engineering to promote wound healing in the immunocompromised host: Current challenges and future directions

As regenerative medicine matures as a field, more promising technologies are being translated from the benchtop to the clinic. However, many of these strategies are designed with otherwise healthy hosts in mind and validated in animal models without other co-morbidities. In reality, many of the patient populations benefiting from drug delivery and tissue engineering-based devices to enhance wound healing also have significant underlying immunodeficiency. Specifically, patients suffering from diabetes, malignancy, human immunodeficiency virus, post-organ transplantation, and other compromised states have significant pleotropic immune defects that affect wound healing. In this work, we review the role of different immune cells in the regenerative process, highlight the effect of several common immunocompromised states on wound healing, and discuss different drug delivery strategies for overcoming immunodeficiencies.

Vaginal Delivery of Benzydamine Hydrochloride through Liposomes Dispersed in Mucoadhesive Gels

Liposomal vaginal drug delivery systems are important strategy in the treatment of both topical and systemic diseases. The aim of this study was to develop a vaginal delivery system for benzydamine hydrochloride (BNZ) loaded liposomes dispersed into mucoadhesive gels. The delivery system was also designed for a once a day dosage and to obtain controlled release of the BNZ. For this purpose BNZ containing gel formulations using hydroxypropyl methylcellulose (HPMC) K100M and Carbopol^® 974P, which are composed of polymers that show promising potential as mucoadhesive vaginal delivery systems, were developed. In addition, a BNZ containing liposome formulation was developed for vaginal administration. To improve the vaginal retention time, liposome was incorporated in HPMC K100M and Carbopol^® 974P gel formulations. This system is called lipogel. The developed BNZ liposomes have a slightly negative zeta potential (-1.50±0.16 mV), a 2.25±0.009 µm particle size and a 34% entrapment efficiency. These gels and lipogels have appropriate pH, viscosity, textural properties and mucoadhesive value for vaginal administration. Lipogels were found to be the best formulations for in vitro diffusion and ex vivo mucoadhesion. The work of mucoadhesion obtained from liposomes was in the range of 0.027±0.045 and 0.030±0.017 mJ/cm², while the value obtained from lipogels was between 0.176±0.037 and 0.243±0.53 mJ/cm². N1 and N2 lipogel formulations diffused 57 and 67% of BNZ respectively at the end of 24 h. Moreover, a higher mucoadhesion, which increases drug residence time in comparison to liposomes, could improve BNZ efficacy. In conclusion, BNZ mucoadhesive vaginal lipogel formulations can be promising alternatives to traditional dosage forms for vaginal topical therapy.

EGF and curcumin co-encapsulated nanoparticle/hydrogel system as potent skin regeneration agent

Wound healing is a complex multifactorial process that relies on coordinated signaling molecules to succeed. Epidermal growth factor (EGF) is a mitogenic polypeptide that stimulates wound repair; however, precise control over its application is necessary to reduce the side effects and achieve desired therapeutic benefits. Moreover, the extensive oxidative stress during the wound healing process generally inhibits repair of the injured tissues. Topical applications of antioxidants like curcumin (Cur) could protect tissues from oxidative damage and significantly improve tissue remodeling. To achieve much accelerated wound healing effects, we designed a novel dual drug co-loaded in situ gel-forming nanoparticle/hydrogel system (EGF-Cur-NP/H) which acted not only as a supportive matrix for the regenerative tissue, but also as a sustained drug depot for EGF and Cur. In the established excisional full-thickness wound model, EGF-Cur-NP/H treatment significantly enhanced wound closure through increasing granulation tissue formation, collagen deposition, and angiogenesis, relative to normal saline, nanoparticle/hydrogel (NP/H), Cur-NP/H, and EGF-NP/H treated groups. In conclusion, this study provides a biocompatible in situ gel-forming system for efficient topical application of EGF and Cur in the landscape of tissue repair.

Clindamycin Phosphate Absorption from Nanoliposomal Formulations through Third-Degree Burn Eschar

BACKGROUND

It has been shown that topical nanoliposomal formulations improve burn healing process. On the other hand, it has been shown that liposomal formulations increase drug deposition in the normal skin while decrease their systemic absorption; there is not such data available for burn eschar. Present investigation studies permeation of clindamycin phosphate (CP) through burn eschar from liposomal formulations to answer this question. In this investigation, permeation of CP through fully hydrated third-degree burn eschar was evaluated using solution, normal nanoliposomes and ultradeformable nanoliposomes.

METHODS

Liposomal CP were prepared by thin-film hydration and characterized in terms of size, size distribution, zeta potential, encapsulation efficiency and short-time stability. Then the effect of liposomal lipid concentration on CP absorption was investigated.

RESULTS

The permeability coefficient ratio (liposome/solution) and permeation lag-time ratio (liposome/solution) of CP through burn eschar at 20 Mm lipid concentration were 0.81±0.21 and 1.19±1.30 respectively, indicating the retardation effects of liposomes. Data also showed that increasing liposomal lipid concentration from 20 to 100 mM, clindamycin permeation decreased by about 2 times. There was no difference between normal liposome and ultradeformable liposome in terms of clindamycin absorption.

CONCLUSION

Nanoliposomes could decrease trans-eschar absorption of CP, in good agreement with normal skin data, and might indicate CP deposition in the eschar tissue.

Decellularized scaffolds containing hyaluronic acid and EGF for promoting the recovery of skin wounds

There is no effective therapy for the treatment of deep and large area skin wounds. Decellularized scaffolds can be prepared from animal tissues and represent a promising biomaterial for investigation in tissue regeneration studies. In this study, MTT assay showed that epidermal growth factor (EGF) increased NIH3T3 cell proliferation in a bell-shaped dose response, and the maximum cell proliferation was achieved at a concentration of 25 ng/ml. Decellularized scaffolds were prepared from pig peritoneum by a series of physical and chemical treatments. Hyaluronic acid (HA) increased EGF adsorption to the scaffolds. Decellularized scaffolds containing HA sustained the release of EGF compared to no HA. Rabbits contain relatively large skin surface and are less expensive and easy to be taken care, so that a rabbit wound healing model was use in this study. Four full-thickness skin wounds were created in each rabbit for evaluation of the effects of the scaffolds on the skin regeneration. Wounds covered with scaffolds containing either 1 or 3 μg/ml EGF were significantly smaller than with vaseline oil gauzes or with scaffolds alone, and the wounds covered with scaffolds containing 1 μg/ml EGF recovered best among all four wounds. Hematoxylin-Eosin staining confirmed these results by demonstrating that significantly thicker dermis layers were also observed in the wounds covered by the decellularized scaffolds containing HA and either 1 or 3 μg/ml EGF than with vaseline oil gauzes or with scaffolds alone. In addition, the scaffolds containing HA and 1 μg/ml EGF gave thicker dermis layers than HA and 3 μg/ml EGF and showed the regeneration of skin appendages on day 28 post-transplantation. These results demonstrated that decellularized scaffolds containing HA and EGF could provide a promising way for the treatment of human skin injuries.

Comparison of efficacy of topical phenytoin with hypericin in second-degree burn wound healing: an experimental study in rats

Background

This experiment was performed to compare the effects of Phenytoin (PHT) and Hypericin (HP) cream on healing of burn wounds in rats.

Material/Methods

Twenty rats were divided into 3 groups and second-degree burn wounds were created. The burn wounds in the first, second, and third groups were covered twice daily with PHT cream, HP cream, and saline (control), respectively. At the end of days 3, 7, 14, and 21, full-thickness skin biopsies were done for histopathologic and immunohistochemical analyses.

Results

Histopathologic evaluations at the 14^th day showed that re-epithelialization scores were greater in the HP group than the PHT group, but on day 21, re-epithelialization scores were higher in the PHT group than the HP group. Collagen content on days 3 and 14 in the PHT group was found to be higher than in the HP group. Well-vascularized granulation tissue on day 7 in the PHT group was higher than in other groups. HP and PHT groups had a significant increase in VEGF and TGF-β expression in burn wound healing area compared to the control group on all days.

Conclusions

Topical application of HP can promote re-epithelialization in burn wounds to shorten the wound healing time for superficial burns. Phenytoin, on the other hand, contributes to healing by increasing vascularized granulation tissue and collagen synthesis through re-epithelialization. The increased VEGF and TGF-β expression following PHT and HP treatment strongly indicate that PHT and HP treatment promotes VEGF and TGF-β production and action in the burn wound area.

Evaluation of skin regeneration after burns in vivo and rescue of cells after thermal stress in vitro following treatment with a keratin biomaterial

Thermal burns typically display an injury pattern dictated by the transfer of the thermal energy into the skin and underlying tissues and creation of three zones of injury represented by a necrotic zone of disrupted cells and tissue, an intermediate zone of injured and dying cells, and a distant zone of stressed cells that will recover with proper treatment. The wound healing capabilities of a keratin biomaterial hydrogel were studied in two pilot studies, one using a chemical burn model in mice and the other a thermal burn model in swine. In both studies, keratin was shown to prevent enlargement of the initial wound area and promote faster wound closure. Interestingly, treating thermally stressed dermal fibroblast in culture demonstrated that soluble keratin was able to maintain cell viability and promote proliferation. Separation of so-called alpha and gamma fractions of the keratin biomaterial had differential effects, with the gamma fraction producing more pronounced cell survival and recovery. These results suggest that the gamma fraction, composed essentially of degraded alpha keratin proteins, may facilitate cell rescue after thermal injury. Treatment of burns with gamma keratin may therefore represent a potential therapy for wounds with an intermediate zone of damaged tissue that has the potential to contribute to spontaneous healing.

Experimental study of comparing rhEGF with rhβFGF on improving the quality of wound healing

The mechanism and biological effects of comparing recombinant human epidermal growth factor (rhEGF) with recombinant human basic fibroblast growth factor (rhβFGF) were evaluated on the model of incised wounds on ventral side of rabbit's ears in order to direct their medication in clinical. Total of 72 incised wounds on ventral side of 24 New Zealand rabbits' ears were divided randomly into two therapeutic groups (rhEGF group with 10 μg/cm(2) and rhβFGF group with 100 AU/cm(2)) and a control group (1% silver sulfadiazine cream, SD-Ag). The observation of wounds, the measurements of healing wound area, the calculation of wound closing index, the histopathological examination, the electrical microscopic examination, and the expression of examining integrin β1 mRNA of samples of three groups by in situ hybridization technique were used to evaluate the results of wound healing. The results showed that the wound healing was accelerated in all wounds treated with rhEGF and rhβFGF, and the quality of healing wounds of two therapeutic groups was better than that of the control group. In rhβFGF group, new granulation tissue was more than that of rhEGF group in earlier period and metaphase of healing wound, however, the velocity of re-epithelialization in rhEGF group was faster than that of rhβFGF group in metaphase and late period. The results indicate that rhEGF and rhβFGF can improve wound healing, but the detailed mechanisms and the biological effects were different. rhβFGF may be used to promote the growth of granulation tissue in earlier period and metaphase of healing wound, however, rhEGF may be used to accelerate the velocity of re-epithelialization in metaphase and late period. That rhβFGF and rhEGF were utilized in sequence can not only accelerate the velocity of healing wound and promote the quality of healing wound but also obtain the best ratio of effects versus value.