Healing potential of injectable Aloe vera hydrogel loaded by adipose-derived stem cell in skin tissue-engineering in a rat burn wound model

Design and evaluation of a bilayered dermal/hypodermal 3D model using a biomimetic hydrogel formulation

Due to the limitations of the current skin wound treatments, it is highly valuable to have a wound healing formulation that mimics the extracellular matrix (ECM) and mechanical properties of natural skin tissue. Here, a novel biomimetic hydrogel formulation has been developed based on a mixture of Agarose-Collagen Type I (AC) combined with skin ECM-related components: Dermatan sulfate (DS), Hyaluronic acid (HA), and Elastin (EL) for its application in skin tissue engineering (TE). Different formulations were designed by combining AC hydrogels with DS, HA, and EL. Cell viability, hemocompatibility, physicochemical, mechanical, and wound healing properties were investigated. Finally, a bilayered hydrogel loaded with fibroblasts and mesenchymal stromal cells was developed using the Ag-Col I-DS-HA-EL (ACDHE) formulation. The ACDHE hydrogel displayed the best in vitro results and acceptable physicochemical properties. Also, it behaved mechanically close to human native skin and exhibited good cytocompatibility. Environmental scanning electron microscopy (ESEM) analysis revealed a porous microstructure that allows the maintenance of cell growth and ECM-like structure production. These findings demonstrate the potential of the ACDHE hydrogel formulation for applications such as an injectable hydrogel or a bioink to create cell-laden structures for skin TE.

Aloe Barbadensis Miller (Aloe Vera)

Aloe Barbadensis Miller (Aloe Vera, AV) is a widely recognized for its diverse health-promoting, skin care, and medicinal properties. This narrative review provides a comprehensive overview of AV's bioactive compounds, pharmacological activities, potential applications, its toxic and adverse effects, as well as the clinical evidence supporting AV's efficacy in disease prevention. AV contains over 200 bioactive compounds, with the inner clear gel of the leaves containing the majority of these compounds. These include phenolic acids (274.5-307.5 mg/100 g), flavonoids. (3.63-4.70 g/kg), polysaccharides (3.82-6.55 g/kg), saponins, alkaloids, terpenoids, and anthraquinone derivatives. Findings from clinical studies involving both humans and animals highlight the therapeutic potential of AV across diverse health domains. The studies demonstrate AV's efficacy in reducing blood glucose levels, exhibiting antioxidant and immunomodulatory effects, inducing apoptosis in cancer cells, protecting the liver from damage, and displaying antimicrobial properties. In the fields of dermatology and dentistry, AV has also been observed to promote skin and oral health. However, it is imperative to acknowledge potential risks, adhere to recommended dosages, and seek guidance from healthcare experts before employing AV as a natural therapeutic option. Moreover, considering safety concerns, further well-designed randomized controlled trials are necessary to substantiate the potential benefits of AV and comprehensively assess any associated risks.

Mesenchymal stem cell transplantation in burn wound healing: uncovering the mechanisms of local regeneration and tissue repair

Burn injuries pose a significant healthcare burden worldwide, often leading to long-term disabilities and reduced quality of life. To explore the impacts of the transplantation of mesenchymal stem cells (MSCs) on the healing of burns and the levels of serum cytokines, 60 fully grown Sprague-Dawley rats were randomly divided into three groups (n = 20 each): group I (control), group II (burn induction), and group III (burn induction + bone marrow (BM)-MSC transplantation). Groups II and III were further divided into four subgroups (n = 5 each) based on euthanasia duration (7, 14, 21, and 28 days post transplant). The experiment concluded with an anesthesia overdose for rat death. After 7, 14, 21, and 28 days, the rats were assessed by clinical, laboratory, and histopathology investigations. The results revealed significant improvements in burn healing potentiality in the group treated with MSC. Furthermore, cytokine levels were measured, with significant increases in interleukin (IL)-6 and interferon alpha (IFN) observed, while IL-10 and transforming growth factor beta (TGF-β) decreased at 7 days and increased until 28 days post burn. Also, the group that underwent the experiment exhibited increased levels of pro-inflammatory cytokines and the anti-inflammatory cytokine IL-10 when compared to the control group. Histological assessments showed better re-epithelialization, neovascularization, and collagen deposition in the experimental group, suggesting that MSC transplantation in burn wounds may promote burn healing by modulating the immune response and promoting tissue regeneration.

Progress in injectable hydrogels for the treatment of incompressible bleeding: an update

Uncontrollable haemorrhage from deep, noncompressible wounds remains a persistent and intractable challenge, accounting for a very high proportion of deaths in both war and disaster situations. Recently, injectable hydrogels have been increasingly studied as potential haemostatic materials, highlighting their enormous potential for the management of noncompressible haemorrhages. In this review, we summarize haemostatic mechanisms, commonly used clinical haemostatic methods, and the research progress on injectable haemostatic hydrogels. We emphasize the current status of injectable hydrogels as haemostatic materials, including their physical and chemical properties, design strategy, haemostatic mechanisms, and application in various types of wounds. We discuss the advantages and disadvantages of injectable hydrogels as haemostatic materials, as well as the opportunities and challenges involved. Finally, we propose cutting-edge research avenues to address these challenges and opportunities, including the combination of injectable hydrogels with advanced materials and innovative strategies to increase their biocompatibility and tune their degradation profile. Surface modifications for promoting cell adhesion and proliferation, as well as the delivery of growth factors or other biologics for optimal wound healing, are also suggested. We believe that this paper will inform researchers about the current status of the use of injectable haemostatic hydrogels for noncompressible haemorrhage and spark new ideas for those striving to propel this field forward.

The efficacy of adipose-derived stem cells in burn injuries: a systematic review

BACKGROUND

Burn injuries can be associated with prolonged healing, infection, a substantial inflammatory response, extensive scarring, and eventually death. In recent decades, both the mortality rates and long-term survival of severe burn victims have improved significantly, and burn care research has increasingly focused on a better quality of life post-trauma. However, delayed healing, infection, pain and extensive scar formation remain a major challenge in the treatment of burns. ADSCs, a distinct type of mesenchymal stem cells, have been shown to improve the healing process. The aim of this review is to evaluate the efficacy of ADSCs in the treatment of burn injuries.

METHODS

A systematic review of the literature was conducted using the electronic databases PubMed, Web of Science and Embase. The basic research question was formulated with the PICO framework, whereby the usage of ADSCs in the treatment of burns in vivo was determined as the fundamental inclusion criterion. Additionally, pertinent journals focusing on burns and their treatment were screened manually for eligible studies. The review was registered in PROSPERO and reported according to the PRISMA statement.

RESULTS

Of the 599 publications screened, 21 were considered relevant to the key question and were included in the present review. The included studies were almost all conducted on rodents, with one exception, where pigs were investigated. 13 of the studies examined the treatment of full-thickness and eight of deep partial-thickness burn injuries. 57,1 percent of the relevant studies have demonstrated that ADSCs exhibit immunomodulatory effects during the inflammatory response. 16 studies have shown improved neovascularisation with the use of ADSCs. 14 studies report positive influences of ADSCs on granulation tissue formation, while 11 studies highlight their efficacy in promoting re-epithelialisation. 11 trials demonstrated an improvement in outcomes during the remodelling phase.

CONCLUSION

In conclusion, it appears that adipose-derived stem cells demonstrate remarkable efficacy in the field of regenerative medicine. However, the usage of ADSCs in the treatment of burns is still at an early experimental stage, and further investigations are required in order to examine the potential usage of ADSCs in future clinical burn care.

3D printable, injectable amyloid-based composite hydrogel of bovine serum albumin and aloe vera for rapid diabetic wound healing

Protein-based biomaterials, particularly amyloids, have sparked considerable scientific interest in recent years due to their exceptional mechanical strength, excellent biocompatibility and bioactivity. In this work, we have synthesized a novel amyloid-based composite hydrogel consisting of bovine serum albumin (BSA) and aloe vera (AV) gel to utilize the medicinal properties of the AV gel and circumvent its mechanical frangibility. The synthesized composite hydrogel demonstrated an excellent porous structure, self-fluorescence, non-toxicity, and controlled rheological properties. Moreover, this hydrogel possesses inherent antioxidant and antibacterial properties, which accelerate the rapid healing of wounds. The in vitro wound healing capabilities of the synthesized composite hydrogel were evaluated using 3T3 fibroblast cells. Moreover, the efficacy of the hydrogel in accelerating chronic wound healing via collagen crosslinking was investigated through in vivo experiments using a diabetic mouse skin model. The findings indicate that the composite hydrogel, when applied, promotes wound healing by inducing collagen deposition and upregulating the expression of vascular endothelial growth factor (VEGF) and its receptors. We also demonstrate the feasibility of the 3D printing of the BSA-AV hydrogel, which can be tailored to treat various types of wound. The 3D printed hydrogel exhibits excellent shape fidelity and mechanical properties that can be utilized for personalized treatment and rapid chronic wound healing. Taken together, the BSA-AV hydrogel has great potential as a bio-ink in tissue engineering as a dermal substitute for customizable skin regeneration.

Exosome/metformin-loaded self-healing conductive hydrogel rescues microvascular dysfunction and promotes chronic diabetic wound healing by inhibiting mitochondrial fission

Chronic diabetic wounds remain a globally recognized clinical challenge. They occur due to high concentrations of reactive oxygen species and vascular function disorders. A promising strategy for diabetic wound healing is the delivery of exosomes, comprising bioactive dressings. Metformin activates the vascular endothelial growth factor pathway, thereby improving angiogenesis in hyperglycemic states. However, multifunctional hydrogels loaded with drugs and bioactive substances synergistically promote wound repair has been rarely reported, and the mechanism of their combinatorial effect of exosome and metformin in wound healing remains unclear. Here, we engineered dual-loaded hydrogels possessing tissue adhesive, antioxidant, self-healing and electrical conductivity properties, wherein 4-armed SH-PEG cross-links with Ag⁺, which minimizes damage to the loaded goods and investigated their mechanism of promotion effect for wound repair. Multiwalled carbon nanotubes exhibiting good conductivity were also incorporated into the hydrogels to generate hydrogen bonds with the thiol group, creating a stable three-dimensional structure for exosome and metformin loading. The diabetic wound model of the present study suggests that the PEG/Ag/CNT-M + E hydrogel promotes wound healing by triggering cell proliferation and angiogenesis and relieving peritraumatic inflammation and vascular injury. The mechanism of the dual-loaded hydrogel involves reducing the level of reactive oxygen species by interfering with mitochondrial fission, thereby protecting F-actin homeostasis and alleviating microvascular dysfunction. Hence, we propose a drug-bioactive substance combination therapy and provide a potential mechanism for developing vascular function-associated strategies for treating chronic diabetic wounds.

Antioxidant Biomaterials in Cutaneous Wound Healing and Tissue Regeneration: A Critical Review

Natural-based biomaterials play an important role in developing new products for medical applications, primarily in cutaneous injuries. A large panel of biomaterials with antioxidant properties has revealed an advancement in supporting and expediting tissue regeneration. However, their low bioavailability in preventing cellular oxidative stress through the delivery system limits their therapeutic activity at the injury site. The integration of antioxidant compounds in the implanted biomaterial should be able to maintain their antioxidant activity while facilitating skin tissue recovery. This review summarises the recent literature that reported the role of natural antioxidant-incorporated biomaterials in promoting skin wound healing and tissue regeneration, which is supported by evidence from in vitro, in vivo, and clinical studies. Antioxidant-based therapies for wound healing have shown promising evidence in numerous animal studies, even though clinical studies remain very limited. We also described the underlying mechanism of reactive oxygen species (ROS) generation and provided a comprehensive review of ROS-scavenging biomaterials found in the literature in the last six years.

Aloe vera and copaiba oleoresin-loaded chitosan films for wound dressings: microbial permeation, cytotoxicity, and in vivo proof of concept

Chitosan films are commonly used for wound dressing, provided that this polymer has healing, mucoadhesiveness and antimicrobial properties. These properties can be further reinforced by the combination of chitosan with polysaccharides and glycoproteins present in aloe vera, together with copaiba oleoresin's pharmacological activity attributed to sesquiterpenes. In this work, we developed chitosan films containing either aloe vera, copaiba oil or both, by casting technique, and evaluated their microbial permeation, antimicrobial activity, cytotoxicity, and in vivo healing potential in female adult rats. None of the developed chitosan films promoted microbial permeation, while the cytotoxicity in Balb/c 3 T3 clone A31 cell line revealed no toxicity of films produced with 2 % of chitosan and up to 1 % of aloe vera and copaiba oleoresin. Films obtained with either 0.5 % chitosan or 0.5 % copaiba oleoresin induced cell proliferation which anticipate their potential for closure of wound and for the healing process. The in vivo results confirmed that tested films (0.5 % copaiba-loaded chitosan film and 0.5 % aloe vera-loaded chitosan film) were superior to a commercial dressing film. For all tested groups, a fully formed epithelium was seen, while neoformation of vessels seemed to be greater in formulations-treated groups than those treated with the control. Our work confirms the added value of combining chitosan with aloe vera and copaiba oil in the healing process of wounds.

Recent progress in the manipulation of biochemical and biophysical cues for engineering functional tissues

Tissue engineering (TE) is currently considered a cutting-edge discipline that offers the potential for developing treatments for health conditions that negatively affect the quality of life. This interdisciplinary field typically involves the combination of cells, scaffolds, and appropriate induction factors for the regeneration and repair of damaged tissue. Cell fate decisions, such as survival, proliferation, or differentiation, critically depend on various biochemical and biophysical factors provided by the extracellular environment during developmental, physiological, and pathological processes. Therefore, understanding the mechanisms of action of these factors is critical to accurately mimic the complex architecture of the extracellular environment of living tissues and improve the efficiency of TE approaches. In this review, we recapitulate the effects that biochemical and biophysical induction factors have on various aspects of cell fate. While the role of biochemical factors, such as growth factors, small molecules, extracellular matrix (ECM) components, and cytokines, has been extensively studied in the context of TE applications, it is only recently that we have begun to understand the effects of biophysical signals such as surface topography, mechanical, and electrical signals. These biophysical cues could provide a more robust set of stimuli to manipulate cell signaling pathways during the formation of the engineered tissue. Furthermore, the simultaneous application of different types of signals appears to elicit synergistic responses that are likely to improve functional outcomes, which could help translate results into successful clinical therapies in the future.

Chorioallantoic Membrane Assay at the Cross-Roads of Adipose-Tissue-Derived Stem Cell Research

With a history of more than 100 years of different applications in various scientific fields, the chicken chorioallantoic membrane (CAM) assay has proven itself to be an exceptional scientific model that meets the requirements of the replacement, reduction, and refinement principle (3R principle). As one of three extraembryonic avian membranes, the CAM is responsible for fetal respiration, metabolism, and protection. The model provides a unique constellation of immunological, vascular, and extracellular properties while being affordable and reliable at the same time. It can be utilized for research purposes in cancer biology, angiogenesis, virology, and toxicology and has recently been used for biochemistry, pharmaceutical research, and stem cell biology. Stem cells and, in particular, mesenchymal stem cells derived from adipose tissue (ADSCs) are emerging subjects for novel therapeutic strategies in the fields of tissue regeneration and personalized medicine. Because of their easy accessibility, differentiation profile, immunomodulatory properties, and cytokine repertoire, ADSCs have already been established for different preclinical applications in the files mentioned above. In this review, we aim to highlight and identify some of the cross-sections for the potential utilization of the CAM model for ADSC studies with a focus on wound healing and tissue engineering, as well as oncological research, e.g., sarcomas. Hereby, the focus lies on the combination of existing evidence and experience of such intersections with a potential utilization of the CAM model for further research on ADSCs.

Polysaccharide-Based Multifunctional Hydrogel Bio-Adhesives for Wound Healing: A Review

Wound healing is a long-term and complex biological process that involves multiple hemostasis, inflammation, proliferation, and remodeling stages. In order to realize comprehensive and systematic wound management, appropriate wound treatment bio-adhesives are urgently needed. Hydrogel bio-adhesives have excellent properties and show unique and remarkable advantages in the field of wound management. This review begins with a detailed description of the design criteria and functionalities of ideal hydrogel bio-adhesives for wound healing. Then, recent advances in polysaccharide-based multifunctional hydrogel bio-adhesives, which involve chitosan, hyaluronic acid, alginate, cellulose, dextran, konjac glucomannan, chondroitin sulfate, and other polysaccharides, are comprehensively discussed. Finally, the current challenges and future research directions of polysaccharide-based hydrogel bio-adhesives for wound healing are proposed to stimulate further exploration by researchers.

Adipose-derived stem cells applied in skin diseases, wound healing and skin defects: a review

Adipose tissue presents a comparably easy source for obtaining stem cells, and more studies are increasingly investigating the therapeutic potential of adipose-derived stem cells. Wound healing, especially in chronic wounds, and treatment of skin diseases are some of the fields investigated. In this narrative review, the authors give an overview of some of the latest studies concerning wound healing as well as treatment of several skin diseases and concentrate on the different forms of application of adipose-derived stem cells.

Advances of hydrogel combined with stem cells in promoting chronic wound healing

Wounds can be divided into two categories, acute and chronic. Acute wounds heal through the normal wound healing process. However, chronic wounds take longer to heal, leading to inflammation, pain, serious complications, and an economic burden of treatment costs. In addition, diabetes and burns are common causes of chronic wounds that are difficult to treat. The rapid and thorough treatment of chronic wounds, including diabetes wounds and burns, represents a significant unmet medical need. Wound dressings play an essential role in chronic wound treatment. Various biomaterials for wound healing have been developed. Among these, hydrogels are widely used as wound care materials due to their good biocompatibility, moisturizing effect, adhesion, and ductility. Wound healing is a complex process influenced by multiple factors and regulatory mechanisms in which stem cells play an important role. With the deepening of stem cell and regenerative medicine research, chronic wound treatment using stem cells has become an important field in medical research. More importantly, the combination of stem cells and stem cell derivatives with hydrogel is an attractive research topic in hydrogel preparation that offers great potential in chronic wound treatment. This review will illustrate the development and application of advanced stem cell therapy-based hydrogels in chronic wound healing, especially in diabetic wounds and burns.

Exploring Silk Sericin for Diabetic Wounds: An In Situ-Forming Hydrogel to Protect against Oxidative Stress and Improve Tissue Healing and Regeneration

Chronic wounds are one of the most frequent complications that are associated with diabetes mellitus. The overproduction of reactive oxygen species (ROS) is a key factor in the delayed healing of a chronic wound. In the present work, we develop a novel in situ-forming silk sericin-based hydrogel (SSH) that is produced by a simple methodology using horseradish peroxidase (HRP) crosslinking as an advanced dressing for wound healing. The antioxidant and angiogenic effects were assessed in vitro and in vivo after in situ application using an excisional wound-healing model in a genetically-induced diabetic db/db mice and though the chick embryo choriollantoic membrane (CAM) assay, respectively. Wounds in diabetic db/db mice that were treated with SSH closed with reduced granulation tissue, decreased wound edge distance, and wound thickness, when compared to Tegaderm, a dressing that is commonly used in the clinic. The hydrogel also promoted a deposition of collagen fibers with smaller diameter which may have had a boost effect in re-epithelialization. SSH treatment slightly induced two important endogenous antioxidant defenses, superoxide dismutase and catalase. A CAM assay made it possible to observe that SSH led to an increase in the number of newly formed vessels without inducing an inflammatory reaction. The present hydrogel may result in a multi-purpose technology with angiogenic, antioxidant, and anti-inflammatory properties, while advancing efficient and organized tissue regeneration.

Understanding the cellular response of human tenon fibroblast on polycaprolactone-Aloe vera blend fiber

The signalling response is determined by the cell's reaction to different biochemical and biophysical inputs such as stiffness, topological, and structural alignment. The surface patterns at the nano-scale can be an influential factor in cell signalling behaviour. It is important to understand the cellular response to the biophysical cues for biomedical applications. Biomaterials have an important role in regenerative tissue engineering. In this study, we have fabricated electrospun polycaprolactone (PCL) and PCL-Aloe vera (PCL-AV) nanofibrous matrix and studied its effect on the human tenon fibroblast (HTF) cellular and morphological changes. The electrospun fibers were characterized using Scanning Electron Microscope (SEM), Fourier Transform Infrared spectroscopy (FTIR), Atomic Force Microscopy (AFM) and Brunaur, Emette and Teller (BET) analysis for their morphology, composition, topography, surface area and porosity. The results revealed fiber size, roughness and porosity has been altered by addition of AV. The HTF cell viability, proliferation and expression of focal adhesion proteins, such as FAK, Ezrin, Vasp and Cofilin on the PCL-AV fiber matrix were examined. The results showed a change in cellular morphology and a significant change in the cofilin phosphorylation on PCL-AV nanofiber. The influence of Aloe vera composition on the nano-dimension of the PCL has made a significant impact on the cellular morphology at both gene and protein levels. This observation suggests that AV composition in the nanofiber can significantly influence the HTF cellular adhesions.

Advances in Hydrogels for Stem Cell Therapy: Regulation Mechanisms and Tissue Engineering Applications

Stem cell therapy has shown unparalleled potential in tissue engineering, but it still faces challenges in the regulation of stem cell fate. Inspired by the native stem cell niche, a...

Melatonin pre-treated bone marrow derived-mesenchymal stem cells prompt wound healing in rat models

Bone marrow derived-mesenchymal stem cells (BMSCs)-based therapy is an outstanding candidate for cutaneous wound healing. Melatonin (MEL) has been reported for its anti-inflammatory as well as tissue regenerative properties. Existing work aimed to explore the potential healing power of BMSCs pre-treated with MEL in a skin wound model. Adult rats were allocated into control, PIO, BMSCs (1 × 10⁵ cells), and MEL/BMSCs groups. On the 21 days post-wounding, tissues were sampled for analysis. The results demonstrated that compared to the control group, MEL/BMSCs therapy induced noticeable decline in wound area and elevated rate of wound retraction. Furthermore, marked increases in tissue hydroxyproline, as well as tissue content and gene expression level of vascular endothelial growth factor in MEL/BMSCs treated-wounded animals. Compared to the untreated control group, marked increases were found in antioxidant enzymatic activities together with elevated GSH levels in wounded tissues after MEL/BMSCs treatment. Moreover, therapeutically handled wounds with MEL/BMSCs revealed low levels of MDA, NO and protein carbonyls. Combined therapy with MEL/BMSCs relieved the inflammation witnessed by decreasing IL-1β, TNF-α and NF-κB levels in wounded tissues. Furthermore, noteworthy rises in levels of TGF-β and gene expression of α-SMA were noticed after MEL/BMSCs application that reveals their anti-scarring properties. Histologically, noticeable improvement in histopathological skin lesions in wound area and elevated the collagen synthesis and deposition. Collectively, the obtained data depict that the pre-treatment of BMSCs with MEL could potentially be a successful strategy for scaling-up the wound healing outcomes more than using BMSCs monotherapy in rat models.

Comparison of therapeutic effects of encapsulated Mesenchymal stem cells in Aloe vera gel and Chitosan-based gel in healing of grade-II burn injuries

Treatment of burn injuries with Mesenchymal stem cells (MSCs) is a great promise due to their unique properties. As two natural and functional wound dressing, Chitosan and Aloe-Vera gel assist wound regeneration by providing a proper environment. In the current study, we aimed to compare the effect of encapsulated BMSCs in Chitosan-based gel and Aloe-Vera gel on the healing of grade-II burn injuries compared to other groups in the rat. After creation of a 2 × 2 cm grade-II burn on dorsal skin of rats, treatments were performed for each group. The wound closure rate and healing properties were evaluated by histopathological analysis on 7, 14, 21 and, 28 days post-treatment. The expression rate of VEGF, Collagen-I and Collagen-III genes was also assessed on days 3, 7, 14, 21 and 28 performing qRT-PCR. The full wound healing with inconsiderable scar formation was achieved for Aloe-vera/BMSCs and Chitosan/BMSCs group on 28th day post-treatment. Pathological results also demonstrated the highest angiogenesis and granulation tissue formation for Aloe-vera/BMSCs and Chitosan/BMSCs groups respectively. The expression level of VEGF, Collagen-I, and Collagen-III genes was significantly higher in these groups on days 14 and 21, compared to other groups. Results demonstrated the synergistic effect of BMSCs when combined with Chitosan or Aloe-vera gel enhanced the healing process of wound healing more than chitosan gel treatment. Therefore, this gel can be considered as effective approaches for treatment of burn injuries.

Fabricating scalable, personalized wound dressings with customizable drug loadings via 3D printing

In recent times, 3D printing has been gaining traction as a fabrication platform for customizable drug dosages as a form of personalized medicine. While this has been recently demonstrated as oral dosages, there is potential to provide the same customizability and personalization as topical applications for wound healing. In this paper, the application of 3D printing to fabricate hydrogel wound dressings with customizable architectures and drug dosages was investigated. Chitosan methacrylate was synthesized and mixed with Lidocaine Hydrochloride and Levofloxacin respectively along with a photoinitiator before being used to print wound dressings of various designs. These designs were then investigated for their effect on drug release rates and profiles. Our results show the ability of 3D printing to customize drug dosages and drug release rates through co-loading different drugs at various positions and varying the thickness of drug-free layers over drug-loaded layers in the wound dressing respectively. Two scale-up approaches were also investigated for their effects on drug release rates from the wound dressing. The influence that each wound dressing design has on the release profile of drugs was also shown by fitting them with drug release kinetic models. This study thus shows the feasibility of utilizing 3D printing to fabricate wound dressings with customizable shapes, drug dosage and drug release rates that can be tuned according to the patient's requirements.

Effectiveness of the adipose stem cells in burn wound healing: literature review

Adipose- stem cells (ASCs) have received much attention in the recent years and several articles have investigated the role of these cells on burn wound healing. To understand the outcomes of the ASCs therapy on burn wound healing, a systematic review was performed. This study was conducted by searching in Pubmed, ISI, and Scopus until May 2021. Thirty-six animal studies were included in this study. The findings revealed that although treatment with ASCs somewhat enhanced the healing rate, cultured ASCs on scaffolds or its combination with hydrogels could significantly increase the viability of ASCs and promote rate of healing. However, clinical studies are necessary to gain a better understanding of the role of ASCs in burn wound healing.

Biomimetic Hydrogels to Promote Wound Healing

Wound healing is a common physiological process which consists of a sequence of molecular and cellular events that occur following the onset of a tissue lesion in order to reconstitute barrier between body and external environment. The inherent properties of hydrogels allow the damaged tissue to heal by supporting a hydrated environment which has long been explored in wound management to aid in autolytic debridement. However, chronic non-healing wounds require added therapeutic features that can be achieved by incorporation of biomolecules and supporting cells to promote faster and better healing outcomes. In recent decades, numerous hydrogels have been developed and modified to match the time scale for distinct stages of wound healing. This review will discuss the effects of various types of hydrogels on wound pathophysiology, as well as the ideal characteristics of hydrogels for wound healing, crosslinking mechanism, fabrication techniques and design considerations of hydrogel engineering. Finally, several challenges related to adopting hydrogels to promote wound healing and future perspectives are discussed.

Functional Hydrogels as Wound Dressing to Enhance Wound Healing

Hydrogels, due to their excellent biochemical and mechnical property, have shown attractive advantages in the field of wound dressings. However, a comprehensive review of the functional hydrogel as a wound dressing is still lacking. This work first summarizes the skin wound healing process and relates evaluation parameters and then reviews the advanced functions of hydrogel dressings such as antimicrobial property, adhesion and hemostasis, anti-inflammatory and anti-oxidation, substance delivery, self-healing, stimulus response, conductivity, and the recently emerged wound monitoring feature, and the strategies adopted to achieve these functions are all classified and discussed. Furthermore, applications of hydrogel wound dressing for the treatment of different types of wounds such as incisional wound and the excisional wound are summarized. Chronic wounds are also mentioned, and the focus of attention on infected wounds, burn wounds, and diabetic wounds is discussed. Finally, the future directions of hydrogel wound dressings for wound healing are further proposed.

Recent trends on burn wound care: hydrogel dressings and scaffolds

Acute and chronic wounds can cause severe physical trauma to patients and also result in an immense socio-economic burden. Thus, wound management has attracted increasing attention in recent years. However, burn wound management is still a major challenge in wound management. Autografts are often considered the gold-standard for burn care, but their application is limited by many factors. Hence, ideal burn dressings and skin substitute dressings are desirable. With the development of biomaterials and progress of tissue engineering technology, some innovative dressings and tissue engineering scaffolds, such as nanofibers, films, foams and hydrogels, have been widely used in the field of biomedicine, especially in wound management. Among them, hydrogels have attracted tremendous attention with their unique advantages. In this review, we discuss the challenges in burn wound management, several crucial design considerations with respect to hydrogels for burn wound healing, and available polymers for hydrogels in burn wound care. In addition, the potential application and plausible prospect of hydrogels are also highlighted.

Exosomes from Adipose-Derived Stem Cells Can Prevent Medication-Related Osteonecrosis of the Jaw

The treatment measures of medication-related osteonecrosis of the jaw (MRONJ) is a worldwide challenge in oral and maxillofacial surgery because of its unclear pathogenesis. Previous studies suggested that mesenchymal stem cells played important roles in promoting MRONJ lesion healing, but the detailed mechanisms were unknown. Increasing numbers of studies have demonstrated that exosomes derived from mesenchymal stem cells, especially adipose-derived stem cells, have key roles in stem cell-based therapies by accelerating bone remodeling, facilitating angiogenesis, and promoting wound healing. We hypothesized that exosomes derived from adipose-derived stem cells can prevent MRONJ by accelerating gingival healing and enhancing bone remodeling processes. Our results may provide a promising therapeutic option for MRONJ clinical therapy.

Effectiveness of the Aloe Vera extract in the treatment of fistula-in-ano

Rationale Considering that anal fistulae are still challenging regarding their treatment due to the risk of fecal incontinence in the most complex cases and the increasing use of phytotherapeutic drugs such as Aloe Vera in medicine, even with proven healing effectiveness, there is interest in researching this drug in the treatment of anal fistulae.

Objective To evaluate the efficacy ofAloe Vera extract in the treatment of anal fistulae in rats.

Method Thirty male Wistar rats weighing 250–300 g were submitted to anal fistula and after 30 days were divided into three groups: Control Group (GCo) (n = 5), Carbopol Group (GCa) (n = 5), and Aloe Vera Group (GAV) (n = 10). In the GCo no treatment was performed, while in the others a daily infusion of 0.3 mL of solution (Carbopol only in GCa and Carbopol plus Aloe Vera extract in the GAV) was performed through the external orifice of the fistula for 30 days. Afterwards, euthanasia was performed and specimens were removed for histological study. It was evaluated the closure of the fistulous tract, the area of the remaining tract, the inflammatory infiltrate and the degree of vascular congestion. The results were submitted to statistical treatment by Kruskall–Wallis test, considering p < 0.05.

Results There was no complete closure of the fistulous tract in any of the animals. The mean area of the remaining tract was 847.2 μm in the GCo, 565.6 μm in the GCa and 377.8 μm in the GAV (p < 0.05). The mean of the inflammatory infiltrate score was 2.4 in the GCo, 2.4 in the GCa and 2.3 in the GAV (p > 0.05), while in the evaluation of vascular congestion, we observed a mean of 1.6 in the GCo, 1.4 in GCa and 1.1 in GAV (p < 0.05).

Conclusion The extract of Aloe vera was able to reduce the lumen of the fistulous tract and reduce the degree of vascular congestion; however, it did not allow the complete closure of the fistulous tract nor diminished the inflammatory process.

Immunobiology and Application of Aloe Vera-Based Scaffolds in Tissue Engineering

Aloe vera (AV), a succulent plant belonging to the Liliaceae family, has been widely used for biomedical and pharmaceutical application. Its popularity stems from several of its bioactive components that have anti-oxidant, anti-microbial, anti-inflammatory and even immunomodulatory effects. Given such unique multi-modal biological impact, AV has been considered as a biomaterial for regenerative medicine and tissue engineering applications, where tissue repair and neo-angiogenesis are vital. This review outlines the growing scientific evidence that demonstrates the advantage of AV as tissue engineering scaffolds. We particularly highlight the recent advances in the application of AV-based scaffolds. From a tissue engineering perspective, it is pivotal that the implanted scaffolds strike an appropriate foreign body response to be well-accepted in the body without complications. Herein, we highlight the key cellular processes that regulate the foreign body response to implanted scaffolds and underline the immunomodulatory effects incurred by AV on the innate and adaptive system. Given that AV has several beneficial components, we discuss the importance of delving deeper into uncovering its action mechanism and thereby improving material design strategies for better tissue engineering constructs for biomedical applications.

Differential Biological Behavior of Fibroblasts and Endothelial Cells under Aloe vera Gel Culturing

Aloe vera is used for its large variety of biological activities such as wound healing, anti-fungal, anti-inflammatory, hypoglycemic, immunomodulatory, gastroprotective, and anti-cancer. Although the beneficial effects of Aloe vera on wound healing have been proven, little is known about its effects at the cellular level. In this study, we evaluated the angiogenic and migrative effects of Aloe vera gel on fibroblasts and endothelial cells. Fibroblasts and endothelial cells were cultured in monolayer conditions with low glucose DMEM with 10% serum and 1% penicillin-streptomycin. Fresh and mature leaves of Aloe vera were used for gel preparation. Cell proliferation and morphology were studied by an inverted microscope. The migration of fibroblasts was assessed by scratch assay. MTT assay was performed for cell viability assessment, and real-time RT-PCR was used for evaluation of PECAM-1, integrin α1 and β1 transcription. After two days, the protein level of PECAM-1 was detected by flow cytometry. Our results showed that Aloe vera has a higher proliferative effect on fibroblasts in comparison with endothelial cells. Aloe vera also induced the migration of fibroblasts. The viability of both types of cells was similar to control ones. Integrin α_1, β₁ and PECAM-1 gene expression increased significantly (P <0.005) in Aloe vera treated fibroblasts and endothelial cells in comparison with the control groups. However, the expression of these genes was significantly higher in fibroblasts in comparison with endothelial cells. Protein levels of PECAM-1 showed no change in both cell types upon Aloe vera treatment. Aloe vera gel induced angiogenic and cell adhesion properties in fibroblasts more than endothelial cells. Further investigations are needed to show the main role of fibroblasts rather than endothelial cells in wound healing by Aloe vera administration.

Systematic Review of Stem-Cell-Based Therapy of Burn Wounds: Lessons Learned from Animal and Clinical Studies

Treatment of severe burn wounds presents a daunting medical challenge, and novel approaches promoting healing and reducing scarring are highly desirable. The application of mesenchymal stem/stromal cells (MSCs) has been suggested as a novel treatment. In this paper, we present systematic reviews of pre-clinical and clinical studies of MSC therapy for second- or third-degree thermal burn wounds. Following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines, the PubMed and Embase databases were searched, and interventional studies of MSC therapy using rodent models (21 studies) or human burn patients (three studies) were included in the pre-clinical and clinical reviews, respectively, where both overall outcome and wound-healing-phase-specific methodologies and effects were assessed. The pre-clinical studies demonstrated a promising effect of the application of MSCs on several wound healing phases. The clinical studies also suggested that the MSC treatment was beneficial, particularly in the remodeling phase. However, the limited number of studies, their lack of homogeneity in study design, relatively high risk of bias, lack of reporting on mode of action (MOA), and discontinuity of evidence restrict the strength of these findings. This comprehensive review presents an overview of available methodologies to assess the MOA of MSC treatment for distinct wound healing phases. Furthermore, it includes a set of recommendations for the design of high-quality clinical studies that can determine the efficacy of MSCs as a therapy for burn wounds.

Aloe vera: A Medicinal Plant Used in Skin Wound Healing

Skin injury is a major problem threatening human physical and mental health, and how to promote wound healing has been the focus. Developing new wound dressings is an important strategy in skin regeneration. Aloe vera is a medicinal plant with a long history, complex constituents, and various pharmacological activities. Many studies have shown that A. vera plays an important role in promoting wound healing. Adding A. vera to wound dressing has become an ideal way. This review will describe the process of skin injury and wound healing and analyze the role of A. vera in wound healing. In addition, the types of wound dressing and the applications of A. vera in wound dressing will be discussed.

Repositioning Natural Antioxidants for Therapeutic Applications in Tissue Engineering

Although a large panel of natural antioxidants demonstrate a protective effect in preventing cellular oxidative stress, their low bioavailability limits therapeutic activity at the targeted injury site. The importance to deliver drug or cells into oxidative microenvironments can be realized with the development of biocompatible redox-modulating materials. The incorporation of antioxidant compounds within implanted biomaterials should be able to retain the antioxidant activity, while also allowing graft survival and tissue recovery. This review summarizes the recent literature reporting the combined role of natural antioxidants with biomaterials. Our review highlights how such functionalization is a promising strategy in tissue engineering to improve the engraftment and promote tissue healing or regeneration.

Novel Nanocarriers for the Treatment of Wound Healing

The sequence of biochemical and cellular responses restoring the integrity of the subcutaneous tissue of the skin is termed as wound healing. Inflammatory cytokine suppression and inflammatory transduction cascades are the major targets for wound healing. Formulations for wound healing should promote neovascularization and angiogenic pathways by increasing the expression of vascular endothelial growth factor, fibroblast growth factor, and platelet-derived growth factor. Medication used for wound healing promotes antiinflammatory associated with anti-bacterial action. In order to boost the effectiveness of current medical treatments, the cutting-edge nanotechnology offers many novel therapies. This review summarized and discussed wound healing, types of wounds, natural materials used for wound healing, metallic nanoparticles and current nano drug delivery systems used for wound healing with special emphasis on the angiogenesis role in the healing of wounds.

Hydrogel Dressings for the Treatment of Burn Wounds: An Up-To-Date Overview

Globally, the fourth most prevalent devastating form of trauma are burn injuries. Ideal burn wound dressings are fundamental to facilitate the wound healing process and decrease pain in lower time intervals. Conventional dry dressing treatments, such as those using absorbent gauze and/or absorbent cotton, possess limited therapeutic effects and require repeated dressing changes, which further aggravate patients' suffering. Contrariwise, hydrogels represent a promising alternative to improve healing by assuring a moisture balance at the burn site. Most studies consider hydrogels as ideal candidate materials for the synthesis of wound dressings because they exhibit a three-dimensional (3D) structure, which mimics the natural extracellular matrix (ECM) of skin in regard to the high-water amount, which assures a moist environment to the wound. There is a wide variety of polymers that have been used, either alone or blended, for the fabrication of hydrogels designed for biomedical applications focusing on treating burn injuries. The aim of this paper is to provide an up-to-date overview of hydrogels applied in burn wound dressings.

Self-assembled cell sheets composed of mesenchymal stem cells and gelatin nanofibers for the treatment of full-thickness wounds

Gelatin-layered PCL nanofibrils for 3D cell sheet formation were composed with adipocyte-derived stem cells for wound healing.