Acemannan accelerates cell proliferation and skin wound healing through AKT/mTOR signaling pathway

Hybrid crystalline bioparticles with nanochannels encapsulating acemannan from Aloe vera: Structure and interaction with lipid membranes

Smart nanocarrier-based bioactive delivery systems are a current focus in nanomedicine for allowing and boosting diverse disease treatments. In this context, the design of hybrid lipid-polymer particles can provide structure-sensitive features for tailored, triggered, and stimuli-responsive devices. In this work, we introduce hybrid cubosomes that have been surface-modified with a complex of chitosan-N-arginine and alginate, making them pH-responsive. We achieved high-efficiency encapsulation of acemannan, a bioactive polysaccharide from Aloe vera, within the nanochannels of the bioparticle crystalline structure and demonstrated its controlled release under pH conditions mimicking the gastric and intestinal environments. Furthermore, an acemannan-induced phase transition from Im3m cubic symmetry to inverse hexagonal HII phase enhances the bioactive delivery by compressing the lattice spacing of the cubosome water nanochannels, facilitating the expulsion of the encapsulated solution. We also explored the bioparticle interaction with membranes of varying curvatures, revealing thermodynamically driven affinity towards high-curvature lipid membranes and inducing morphological transformations in giant unilamellar vesicles. These findings underscore the potential of these structure-responsive, membrane-active smart bioparticles for applications such as pH-triggered drug delivery platforms for the gastrointestinal tract, and as modulators and promoters of cellular internalization.

Review of Malaysian medicinal plants with potential wound healing activity

Wound is defined as the damage to biological tissues including skin, mucous membranes and organ tissues. The acute wound heals in less than 4 weeks without complications, while a chronic wound takes longer than 6 weeks to heal. Wound healing occurs in 4 phases, namely, coagulation, inflammatory, proliferative and remodeling phases. Triclosan and benzalkonium chloride are commonly used as skin disinfectants in wound healing. However, they cause allergic contact dermatitis and antibiotic resistance. Medicinal plants are widely studied due to the limited availability of wound healing agents. The present review included six commonly available medicinal plants in Malaysia such as Aloe barbadensis Miller, Carica papaya Linn., Centella asiatica Linn., Cymbopogon nardus Linn., Ficus benghalensis Linn. and Hibiscus rosa sinensis Linn. Various search engines and databases were used to obtain the scientific findings, including Google Scholar, ScienceDirect, PubMed Central and Research Gate. The review discussed the possible mechanism of action of medicinal plants and their active constituents in the wound healing process. In addition, their application in nanotechnology and wound dressings was also discussed in detail.

Berberine ameliorates endothelial progenitor cell function and wound healing in vitro and in vivo via the miR-21-3p/RRAGB axis for venous leg ulcers

Purpose

Venous leg ulcers (VLUs) are prevalent chronic wounds with limited treatment options. This study aimed to investigate the potential of berberine to enhance endothelial progenitor cell (EPC) function in VLU healing.

Methods

Histopathological changes and inflammatory cytokine levels in a deep venous thrombosis (DVT) mouse model were assessed using HE staining and ELISA assays. A luciferase reporter assay was employed to identify the miR-21-3p and RRAGB targeting relationship. EPC proliferation, migration, and tube formation were evaluated through CCK-8, Transwell, and tubule formation assays, while the mTOR pathway and autophagy-related proteins were analyzed by immunofluorescence staining and western blotting.

Results

Berberine significantly improved EPC functions, such as proliferation, migration, and tube formation in vitro, and enhanced in vivo EPC-mediated wound healing in a DVT mouse model. Furthermore, miR-21-3p was downregulated in EPCs from VLU patients, and its overexpression improved model EPC functions. Mechanistically, RRAGB, which regulates the mTOR pathway, was identified as a potential miR-21-3p target in EPCs. Overexpression of RRAGB inhibited autophagic activity and impaired EPC function.

Conclusion

Berberine shows promise in ameliorating EPC function and promoting wound healing in VLUs. The regulation of the miR-21-3p/RRAGB axis by berberine could offer a promising therapeutic approach for managing VLUs.

Investigations on physiochemical and biomedical properties of Aloe vera - Sterculia gum copolymeric dressings impregnated with antibiotic-anesthetic drugs to enhance wound healing

Recently, various innovative advancements have been made in carbohydrate research to design versatile materials for biomedical applications. The current research focuses on the development of copolymeric hydrogel wound dressings (HWD) using a combination of aloe vera (AV) - sterculia gum (SG) - poly (vinylsulfonic acid) (VSA)-based with the aim to enhancing their efficacy in drug delivery (DD) applications. These hydrogel dressings were encapsulated with levofloxacin and lidocaine to address both microbial infection and pain. Copolymers were characterized by FESEM, SEM, EDS, AFM, 13C NMR, FTIR, XRD, and TGA-DTG analysis. Hydrogel exhibited a fluid absorption capacity of 4.52 ± 0.12 g per gram of polymeric dressing in simulated wound conditions. The hydrogels displayed a sustained release of drugs, demonstrating a non-Fickian diffusion mechanism. Polymer dressings revealed antibacterial, mucoadhesive, antioxidant, biocompatible and non-cytotoxic properties. Additionally, HWD displayed permeability to O2 and water vapour, yet was impermeable to microbial penetration. Overall, the findings of physiological, biochemical and drug delivery properties demonstrated the suitability of materials for wound dressing applications.

New opportunities and perspectives on biosynthesis and bioactivities of secondary metabolites from Aloe vera

Historically, the genus Aloe has been an indispensable part of both traditional and modern medicine. Decades of intensive research have unveiled the major bioactive secondary metabolites of this plant. Recent pandemic outbreaks have revitalized curiosity in aloe metabolites, as they have proven pharmacokinetic profiles and repurposable chemical space. However, the structural complexity of these metabolites has hindered scientific advances in the chemical synthesis of these compounds. Multi-omics research interventions have transformed aloe research by providing insights into the biosynthesis of many of these compounds, for example, aloesone, aloenin, noreugenin, aloin, saponins, and carotenoids. Here, we summarize the biological activities of major aloe secondary metabolites with a focus on their mechanism of action. We also highlight the recent advances in decoding the aloe metabolite biosynthetic pathways and enzymatic machinery linked with these pathways. Proof-of-concept studies on in vitro, whole-cell, and microbial synthesis of aloe compounds have also been briefed. Research initiatives on the structural modification of various aloe metabolites to expand their chemical space and activity are detailed. Further, the technological limitations, patent status, and prospects of aloe secondary metabolites in biomedicine have been discussed.

Acemannan-containing bioactive resin modified glass ionomer demonstrates satisfactory physical and biological properties

Background/purpose

Resin-modified glass ionomers (RMGIs) have been recommended as liner and cement to provide the teeth with mechanical support, a chemical barrier, and thermal insulation. Acemannan, the main polysaccharide extracted from Aloe vera, is a promising inductive material in vitro and in vivo. This study aimed to develop acemannan-containing bioactive resin-modified glass ionomers (RMGIs).

Materials and methods

Acemannan (3%, 5%, and 10%) was added to the three types of RMGIs (RU-HBM1/Fuji II LC/Vitrebond) to generate 3%, 5%, and 10% aceRMGIs (aceRU/aceFuji/aceVB). The materials were evaluated for depth of cure/flexural strength/cumulative fluoride ion release. Cell viability and vascular endothelial growth factor (VEGF) and bone morphogenetic protein-2 (BMP-2) secretion were determined using MTT/apoptosis/necrosis assays, and ELISA kits, respectively. RMGI without acemannan were used as controls.

Results

The aceRMGIs met the ISO requirements for depth of cure and flexural strength. Adding 10% acemannan increased the cumulative fluoride release in the RU and FJ groups, but slightly decreased it in the VB group (P < 0.05). The MTT assay revealed 10% aceRU and all aceFJ groups significantly increased cell viability compared with each control group (P < 0.05). Apoptosis/necrosis assay showed the biocompatibility of all aceRMGIs. Adding acemannan to RMGIs significantly induced VEGF expression in a dose dependent manner while 5% and 10% aceRU significantly induced BMP-2 expression compared with RU group (P < 0.05).

Conclusion

We conclude that 5-10% acemannan in RMGI is the optimal concentration based on its physical properties and ability to induce pulp cell proliferation and growth factor secretion.

The Effect of Aloe vera on the Healing of Diabetic Foot Ulcer: A Randomized, Double-blind Clinical Trial

BACKGROUND

Diabetic foot ulcer (DFU) is a prevalent complication of diabetes that can result in severe consequences. The cost of treating DFUs is high, and there is a lack of new therapies available in developing countries. This has created a demand for complementary and alternative treatments. The objective of this study was to assess the impact of aloe vera gel on the healing process of diabetic foot ulcers.

MATERIALS AND METHODS

The study was a double-blind, randomized, controlled clinical trial. The study samples were 66 patients with diabetic foot ulcers who were randomly assigned to two groups (intervention and control). All ulcers in both groups were washed with normal saline and dressed in sterile gauze. The ulcers in the intervention group were covered with a thin layer of Aloe Vera gel before the dressing. The Bates-Jensen Wound Assessment Tool (BWAT) was used on three occasions, including before the intervention period and at the end of each week. Data were analyzed using SPSS 16.

RESULTS

After three weeks, there was a notable contrast in the recovery pattern of the two groups. The patients who had aloe vera gel added to their dressing showed a more substantial decrease in the mean scores of their BWAT.

CONCLUSION

These findings are promising and suggest that Aloe vera may be a safe and effective adjunctive treatment for diabetic foot ulcers. However, further research is needed to confirm these results and to investigate the underlying mechanisms of aloe vera's therapeutic effect on diabetic foot ulcers.

Synthetic Calcium-Phosphate Materials for Bone Grafting

Synthetic bone grafting materials play a significant role in various medical applications involving bone regeneration and repair. Their ability to mimic the properties of natural bone and promote the healing process has contributed to their growing relevance. While calcium-phosphates and their composites with various polymers and biopolymers are widely used in clinical and experimental research, the diverse range of available polymer-based materials poses challenges in selecting the most suitable grafts for successful bone repair. This review aims to address the fundamental issues of bone biology and regeneration while providing a clear perspective on the principles guiding the development of synthetic materials. In this study, we delve into the basic principles underlying the creation of synthetic bone composites and explore the mechanisms of formation for biologically important complexes and structures associated with the various constituent parts of these materials. Additionally, we offer comprehensive information on the application of biologically active substances to enhance the properties and bioactivity of synthetic bone grafting materials. By presenting these insights, our review enables a deeper understanding of the regeneration processes facilitated by the application of synthetic bone composites.

A New Biomaterial Derived from Aloe vera-Acemannan from Basic Studies to Clinical Application

Aloe vera is a kind of herb rich in polysaccharides. Acemannan (AC) is considered to be a natural polysaccharide with good biodegradability and biocompatibility extracted from Aloe vera and has a wide range of applications in the biomedical field due to excellent immunomodulatory, antiviral, antitumor, and tissue regeneration effects. In recent years, clinical case reports on the application of AC as a novel biomedical material in tissue regenerative medicine have emerged; it is mainly used in bone tissue engineering, pulp-dentin complex regeneration engineering, and soft tissue repair, among other operations. In addition, multiple studies have proved that the new composite products formed by the combination of AC and other compounds have excellent biological and physical properties and have broader research prospects. This paper introduces the preparation process, surface structure, and application forms of AC; summarizes the influence of acetyl functional group content in AC on its functions; and provides a detailed review of the functional properties, laboratory studies, clinical cutting-edge applications, and combined applications of AC. Finally, the current application status of AC from basic research to clinical treatment is analyzed and its prospects are discussed.

Potential of methacrylated acemannan for exerting antioxidant-, cell proliferation-, and cell migration-inducing activities in vitro

BACKGROUND

Acemannan is an acetylated polysaccharide of Aloe vera extract with antimicrobial, antitumor, antiviral, and antioxidant activities. This study aims to optimize the synthesis of acemannan from methacrylate powder using a simple method and characterize it for potential use as a wound-healing agent.

METHODS

Acemannan was purified from methacrylated acemannan and characterized using high-performance liquid chromatography (HPLC), Fourier-transform infrared spectroscopy (FTIR), and ¹H-nuclear magnetic resonance (NMR). 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assays were performed to investigate the antioxidant activity of acemannan and its effects on cell proliferation and oxidative stress damage, respectively. Further, a migration assay was conducted to determine the wound healing properties of acemannan.

RESULTS

We successfully optimized the synthesis of acemannan from methacrylate powder using a simple method. Our results demonstrated that methacrylated acemannan was identified as a polysaccharide with an acetylation degree similar to that in A. vera, with the FTIR revealing peaks at 1739.94 cm^-1 (C = O stretching vibration), 1370 cm^-1 (deformation of the H-C-OH bonds), and 1370 cm^-1 (C-O-C asymmetric stretching vibration); ¹H NMR showed an acetylation degree of 1.202. The DPPH results showed the highest antioxidant activity of acemannan with a 45% radical clearance rate, compared to malvidin, CoQ10, and water. Moreover, 2000 µg/mL acemannan showed the most optimal concentration for inducing cell proliferation, while 5 µg/mL acemannan induced the highest cell migration after 3 h. In addition, MTT assay findings showed that after 24 h, acemannan treatment successfully recovered cell damage due to H₂O₂ pre-treatment.

CONCLUSION

Our study provides a suitable technique for effective acemannan production and presents acemannan as a potential agent for use in accelerating wound healing through its antioxidant properties, as well as cell proliferation- and migration-inducing activities.

Network pharmacology and molecular docking analysis on potential molecular targets and mechanism of action of BRAF inhibitors for application in wound healing

Topical application of BRAF inhibitors has been shown to accelerate wound healing in murine models, which can be extrapolated into clinical applications. The aim of the study was to identify suitable pharmacological targets of BRAF inhibitors and elucidate their mechanisms of action for therapeutic applicability in wound healing, by employing bioinformatics tools including network pharmacology and molecular docking. The potential targets for BRAF inhibitors were obtained from SwissTargetPrediction, DrugBank, CTD, Therapeutic Target Database, and Binding Database. Targets of wound healing were obtained using online databases DisGeNET and OMIM (Online Mendelian Inheritance in Man). Common targets were found by using the online GeneVenn tool. Common targets were then imported to STRING to construct interaction networks. Topological parameters were assessed using Cytoscape and core targets were identified. FunRich was employed to uncover the signaling pathways, cellular components, molecular functions, and biological processes in which the core targets participate. Finally, molecular docking was performed using MOE software. Key targets for the therapeutic application of BRAF inhibitors for wound healing are peroxisome proliferator-activated receptor γ, matrix metalloproteinase 9, AKT serine/threonine kinase 1, mammalian target of rapamycin, and Ki-ras2 Kirsten rat sarcoma viral oncogene homolog. The most potent BRAF inhibitors that can be exploited for their paradoxical activity for wound healing applications are Encorafenib and Dabrafenib. By using network pharmacology and molecular docking, it can be predicted that the paradoxical activity of BRAF inhibitors can be used for their potential application in wound healing.

Beneficial Effects of a Blended Fibroin/Aloe Gel Extract Film on the Biomolecular Mechanism(s) via the MAPK/ERK Pathway Relating to Diabetic Wound Healing

In diabetic patients, the process of wound healing is usually delayed or impaired. A diabetic environment could be associated with dermal fibroblast dysfunction, reduced angiogenesis, the release of excessive proinflammatory cytokines, and senescence features. Alternative therapeutic treatments using natural products are highly demanded for their high potential of bioactive activity in skin repair. Two natural extracts were combined to develop fibroin/aloe gel wound dressing. Our previous studies revealed that the prepared film enhances the healing rate of diabetic foot ulcers (DFUs). Moreover, we aimed to explore its biological effects and underlying biomolecular mechanisms on normal dermal, diabetic dermal, and diabetic wound fibroblasts. Cell culture experiments showed that the γ-irradiated blended fibroin/aloe gel extract film promotes skin wound healing by enhancing cell proliferation and migration, vascular epidermal growth factor (VEGF) secretion, and cell senescence prevention. Its action was mainly linked to the activation of the mitogen-activated protein kinases/extracellular signal-regulated kinase (MAPK/ERK) signaling pathway known to regulate various cellular activities, including proliferation. Therefore, the findings of this study confirm and support our previous data. The blended fibroin/aloe gel extract film displays a biological behavior with favorable properties for delayed wound healing and can be considered as a promising therapeutic approach in the treatment of diabetic nonhealing ulcers.

Deciphering the underlying wound healing mechanisms of Streptocaulon juventas (Lour.) Merr. by integrating network pharmacology, transcriptomics, and experimental validation

ETHNOPHARMACOLOGICAL RELEVANCE

Streptocaulon juventas (Lour.) Merr. (SJ), a traditional Chinese folk medicine, has been widely used for the treatment of dysentery and traumatic injuries since ancient times. However, the mechanisms underlying its wound healing activity remain unclear.

AIM OF THE STUDY

The aim of this study was to evaluate the wound healing activity of SJ and clarify the underlying molecular mechanisms.

MATERIALS AND METHODS

The wound healing activity of an ethanol extract of SJ (ESJ) was confirmed in rat full-thickness wound models. UPLC-Q-TOF-MS/MS was used to analyze the composition of ESJ. Potential molecular targets and signaling pathways involved in the wound healing activity of ESJ were predicted using network pharmacology and transcriptomic analyses. In addition, the L929 cells were used to evaluate the in vitro wound healing activity of ESJ and to verify the predicted pathways.

RESULTS

In rat wound models, ESJ significantly accelerated wound healing and promoted hydroxyproline production in wounds. Network pharmacology and transcriptomic analyses results revealed that ESJ might promote wound healing by activating the AKT and MAPK pathways. In L929 cells, ESJ significantly promoted cell proliferation, migration, and expression of collagen I and α-SMA. Additionally, ESJ treatment increased the phosphorylation of AKT, mTOR, ERK, and p38 in a time- and dose-dependent manner.

CONCLUSIONS

ESJ significantly promoted wound healing in vivo and in vitro. AKT-mTOR and ERK-p38 signaling pathways were involved in the wound healing activity of ESJ.

Statins block mammalian target of rapamycin pathway: a possible novel therapeutic strategy for inflammatory, malignant and neurodegenerative diseases

Inflammation plays a critical role in several diseases such as cancer, gastric, heart and nervous system diseases. Data suggest that the activation of mammalian target of rapamycin (mTOR) pathway in epithelial cells leads to inflammation. Statins, the inhibitors of the 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA), seem to be able to inhibit the mTOR. Statins are considered to have favorable effects on inflammatory diseases by reducing the complications caused by inflammation and by regulating the inflammatory process and cytokines secretion. This critical review collected data on this topic from clinical, in vivo and in vitro studies published between 1998 and June 2022 in English from databases including PubMed, Google Scholar, Scopus, and Cochrane libraries.

Characterization of a bioscaffold containing polysaccharide acemannan and native collagen for pulp tissue regeneration

Dental pulp regeneration exploits tissue engineering concepts using stem cells/scaffolds/growth-factors. Extracted collagen is commonly used as a biomaterial-scaffold due to its biocompatibility/biodegradability and mimics the natural extracellular matrix. Adding biomolecules into a collagen-scaffold enhanced pulp regeneration. Acemannan, β-(1-4)-acetylated-polymannose, is a polysaccharide extracted from aloe vera. Acemannan is a regenerative biomaterial. Therefore, acemannan could be a biomolecule in a collagen-scaffold. Here, acemannan and native collagen were obtained and characterized. The AceCol-scaffold's physical properties were investigated using FTIR, SEM, contact angle, swelling, pore size, porosity, compressive modulus, and degradation assays. The AceCol-scaffold's biocompatibility, growth factor secretion, osteogenic protein expression, and calcification were evaluated in vitro. The AceCol-scaffolds demonstrated higher hydrophilicity, swelling, porosity, and larger pore size than the collagen scaffolds (p < 0.05). Better cell-cell and cell-scaffold adhesion, and dentin extracellular matrix protein (BSP/OPN/DSPP) expression were observed in the AceCol-scaffold, however, DSPP expression was not detected in the collagen group. Significantly increased cellular proliferation, VEGF and BMP2 expression, and mineralization were detected in the AceCol-scaffold compared with the collagen-scaffold (p < 0.05). Computer simulation revealed that acemannan's 3D structure changes to bind with collagen. In conclusion, the AceCol-scaffold synergistically provides better physical and biological properties than collagen. The AceCol-scaffold is a promising material for tissue regeneration.

Differences in Metabolite Composition of Aloe barbadensis Mill. Extracts Lead to Differential Effects on Human Blood T Cell Activity In Vitro

Aloe barbadensis Mill. (Aloe) is used for diverse therapeutic properties including immunomodulation. However, owing to the compositionally complex nature of Aloe, bioactive component(s) responsible for its beneficial properties, though thought to be attributed to polysaccharides (acemannan), remain unknown. We therefore aimed to determine the metabolite composition of various commercial Aloe extracts and assess their effects on human blood T cell activity in vitro. Peripheral blood mononuclear cells (PBMC) from healthy donors were stimulated polyclonally in presence or absence of various Aloe extracts. T cell phenotype and proliferation were investigated by flow cytometry. Aloe extracts were analyzed using targeted ¹H-NMR spectroscopy for standard phytochemical quality characterization and untargeted gas chromatography mass spectrometry (GC-MS) for metabolite profiling. Aloe extracts differing in their standard phytochemical composition had varying effects on T cell activation, proliferation, apoptosis, and cell-death in vitro, although this was not related to the acemannan content. Furthermore, each Aloe extract had its own distinct metabolite profile, where extracts rich in diverse sugar and sugar-derivatives were associated with reduced T cell activity. Our results demonstrate that all commercial Aloe extracts are unique with distinct metabolite profiles, which lead to differential effects on T cell activity in vitro, independent of the acemannan content.

Oral administration of sea cucumber (Stichopus japonicus) protein exerts wound healing effects via the PI3K/AKT/mTOR signaling pathway

This study aimed to investigate the effect of the oral administration of sea cucumber protein (SCP) on wound healing. SCP was isolated and purified from the body wall of Stichopus japonicus. A mouse skin incision model was operated on to evaluate the wound repair effect of SCP. The histological changes in the skin at the wound sites of BALB/c mice were observed by staining with haematoxylin and eosin (H&E) and Masson's trichrome. The enzyme-linked immunosorbent assay (ELISA) was used to analyze the expression of inflammatory cytokines in BALB/c mice. The boost cell migration ability was detected by a scratch assay after HaCaT cells were cultured with digested SCP (dSCP). Western blotting and RT-PCR assays were performed to determine the mechanism of SCP promoting wound healing. As a result, the wound healing rate in the SCP high dose group was 1.3-fold, compared to that in the blank group on day 14. Also, increased epidermal thickness and 1.79-fold collagen deposition contrasted with the blank group. Additionally, SCP could up-regulate the levels of pro-inflammatory factors (IL-1β, IL-6, TNF-α) from day 3 to 7 firstly and decreased from day 7 to 14. IL-8 expression continuously decreased while the level of anti-inflammatory factor (IL-10) increased during the healing stage. Furthermore, the cell closure area reached 67% after being treated with 50 μg mL^-1 of dSCP for 48 h. Cell proliferation was associated with the dSCP-activated PI3K/AKT/mTOR pathway. Taken together, SCP can be orally used as an effective agent for wound repair.

Effect of Aloe vera extract in post-burn skin repair in rats

Background: Burn injury is a global health problem that is most often caused by heat. A burn injury can cause high morbidity and mortality and requires high cost. Therefore, the use of plants as an herbal medicine has the potential to be developed in Indonesia. Aloe vera contains various active ingredients that help the wound healing process, such as glucomannan and acemannan which have the effects on the proliferation of macrophages, fibroblasts, and re-epithelialization. This study aimed to determine the effect of Aloe vera extract in repairing post-burn skin in rats that were analyzed from the number of macrophages, fibroblasts, and epidermal thickness. Methods: This is an experimental study with a posttest-only control group design using 54 Rattus norvegicus Wistar strain rats. The sampling method was simple random sampling consisting of 3 groups, i.e., I. standard group, which were normal rats; II. negative control group, which were given second-degree burns and treated with gel base (without Aloe vera extract); III. treatment groups, which were given second-degree burns and treated with Aloe vera extract gel. Each group was subdivided into three smaller groups (n = 6) according to the time the lesions were evaluated. Skin tissue samplings were carried out on days 3, 14, and 21 after injury to observe the number of macrophages, fibroblasts, and epidermal thickness. Results: There were significant differences in the mean number of macrophages, number of fibroblasts, and epidermal thickness in all groups (p<0.05). Conclusion: Aloe vera extract could accelerate the healing process of burns in rats.

Fibroblast-like cells Promote Wound Healing via PD-L1-mediated Inflammation Resolution

Chronic non-healing wounds fail to progress beyond the inflammatory phase, characterized by a disorder of inflammation resolution. PD-1/PD-L1, a major co-inhibitory checkpoint signaling, plays critical roles in tumor immune surveillance and the occurrence of inflammatory or autoimmune diseases, but its roles in wound healing remains unclear. Here, we described a novel function of PD-L1 in fibroblast-like cells as a positive regulator of wound healing. PD-L1 dynamically expressed on the fibroblast-like cells in the granulation tissue during wound healing to form a wound immunosuppressive microenvironment, modulate macrophages polarization from M1-type to M2-type, and initiates resolution of inflammation, finally accelerate wound healing. Loss of PD-L1 delayed wound healing, especially in mice with LPS-induced severe inflammation. Furthermore, the mainly regulatory mechanism is that combination of FGF-2 and TGF-β1 promotes PD-L1 translation in fibroblasts through enhancing the eIF4E availability regulated by both PI3K-AKT-mTOR-4EBP1 and p38-ERK-MNK signaling pathways. Our results reveal the positive role of PD-L1 in wound healing, and provide a new strategy for the treatment of chronic wounds.

Therapeutic Potential of Skin Stem Cells and Cells of Skin Origin: Effects of Botanical Drugs Derived from Traditional Medicine

Skin, the largest organ of the body, plays a vital role in protecting inner organs. Skin stem cells (SSCs) comprise a group of cells responsible for multiplication and replacement of damaged and non-functional skin cells; thereby help maintain homeostasis of skin functions. SSCs and differentiated cells of the skin such as melanocytes and keratinocytes, have a plethora of applications in regenerative medicine. However, as SSCs reside in small populations in specific niches in the skin, use of external stimulants for cell proliferation in vitro and in vivo is vital. Synthetic and recombinant stimulants though available, pose many challenges due to their exorbitant prices, toxicity issues and side effects. Alternatively, time tested traditional medicine preparations such as polyherbal formulations are widely tested as effective natural stimulants, to mainly stimulate proliferation, and melanogenesis/prevention of melanogenesis of both SSCs and cells of skin origin. Complex, multiple targets, synergistic bioactivities of the phytochemical constituents of herbal preparations amply justify these as natural stimulants. The use of these formulations in clinical applications such as in skin regeneration for burn wounds, wound healing acceleration, enhancement or decrease of melanin pigmentations will be in great demand. Although much multidisciplinary research is being conducted on the use of herbal formulas as stem cell stimulants, very few related clinical trials are yet registered with the NIH clinical trial registry. Therefore, identification/ discovery, in depth investigations culminating in clinical trials, as well as standardization and commercialization of such natural stimulants must be promoted, ensuring the sustainable use of medicinal plants.

Phytochemistry and Biological Activity of Medicinal Plants in Wound Healing: An Overview of Current Research

Wound healing is a complicated process, and the effective management of wounds is a major challenge. Natural herbal remedies have now become fundamental for the management of skin disorders and the treatment of skin infections due to the side effects of modern medicine and lower price for herbal products. The aim of the present study is to summarize the most recent in vitro, in vivo, and clinical studies on major herbal preparations, their phytochemical constituents, and new formulations for wound management. Research reveals that several herbal medicaments have marked activity in the management of wounds and that this activity is ascribed to flavonoids, alkaloids, saponins, and phenolic compounds. These phytochemicals can act at different stages of the process by means of various mechanisms, including anti-inflammatory, antimicrobial, antioxidant, collagen synthesis stimulating, cell proliferation, and angiogenic effects. The application of natural compounds using nanotechnology systems may provide significant improvement in the efficacy of wound treatments. Increasing the clinical use of these therapies would require safety assessment in clinical trials.

Preparation of aloe polysaccharide/honey/PVA composite hydrogel: Antibacterial activity and promoting wound healing

Maintaining a moist and sterile environment is conducive to accelerating wound healing. To develop a natural wound dressing with good water retention capacity and antibacterial activity, we prepared a novel natural multifunctional hydrogel for infected wound healing, which combines the advantages of Aloe polysaccharide (AP) and honey. AP was extracted from Aloe barbadensis, and its structure was characterized by fourier transform infra-red (FT-IR) spectoscopy and nuclear magnetic resonance (NMR) spectroscopy. AP is an acetylated mannan composed of (1 → 4)β-Manp, which is acetylated at C-2, C-3 and C-6 positions. AP/Honey@PVA hydrogel was prepared by cross-linking AP, honey, PVA with borax, which has good mechanical strength and excellent biocompatibility for blood cells, NIH-3T3 cells and L929 cells. The hydrogels showed significant inhibitory effect on Staphylococcus aureus, Escherichia coli and Candida albicans, as well as accelerated the healing of infected full-thickness wound. This study reveals the structure of AP and proves that AP and honey composite hydrogel has potential application prospect in the therapy of infected wounds.

Effect of Aloe vera extract in post-burn skin repair in rats

Background: Burn injury is a global health problem that is most often caused by heat. Burn injury can cause high morbidity and mortality and requires high cost. Therefore, the use of plants as herbal medicine has the potential to be developed in Indonesia. Aloe vera contains various active ingredients that help the wound healing process, such as glucomannan and acemannan which have the effects on the proliferation of macrophages, and fibroblasts, and re-epithelialization. This study aimed to determine the effect of Aloe vera extract in repairing post-burn skin in rats that was analyzed from the number of macrophages and fibroblasts, and epidermal thickness. Methods: This is an experimental study with a posttest-only control group design using 54 Rattus norvegicus Wistar strain rats. The sampling method was simple random sampling consisting of 3 groups, i.e., I. standard group, which were normal rats; II. negative control group, which were given second-degree burns and treated with gel base (without Aloe vera extract); III. treatment groups, which were given second-degree burns and treated with Aloe vera extract gel. Each group was subdivided into three smaller groups (n = 6) according to the time the lesions were evaluated. Skin tissue samplings were carried out on day 3, 14, and 21 after injury to observe the number of macrophages and fibroblasts, and epidermal thickness. Results: There were significant differences in the mean number of macrophages, number of fibroblasts, and epidermal thickness in all groups (p<0.05). Conclusion: Aloe vera extract gel could accelerate the healing process of burns in rats.

Sustained Activity of Stimuli-Responsive Curcumin and Acemannan Based Hydrogel Patches in Wound Healing

Natural plant extract, namely acemannan (Ac) and curcumin (Cur), coencapsulated pluronic micelles, showing thermoresponsive properties, were designed for efficient and safe in vivo wound healing applications. Ac and Cur, widely used antimicrobials, find limited applications because of their low stability, short biological half-life, poor solubility, and low bioavailability. Herein, we report the extraction of Ac from aloe vera and coencapsulation of it with Cur in pluronic micelles to take advantage of the combined effects of both components. Both Ac and Cur preserved their bioactive functionality upon encapsulation. Single photon emission computed tomography imaging confirmed that NPAcC2 hydrogel masked the whole wound by forming a layer. Cur and Ac synergistically resulted in rapid wound closure on the seventh day, and full-grown hair was observed on the 10th day. Individually they both take more than 20 days for wound closure. The increase in the concentration of curcumin increases the healing properties of the material. For days 1, 6, and 10 of the wound dressing experiment, the percentages of wound closure of the mice were the highest for NPAcC2 (i.e., 100%) compared to the untreated control (25%) while maintaining the integrity of the skin. These natural product-based hydrogels have limited side effects vs those caused by commercial drugs in wound healing.

Sub-Flap Use of Nano-Selenium Oxide Solution Enhances Skin Flap Viability in Rats: Study the Novel Role of mTOR and p-mTOR Expression

BACKGROUND

Nano-selenium oxide (NSeO) particles are highly noticeable due to their tissue-protective and antioxidant properties. For this purpose, the effect of NSeO was evaluated on skin flap survival and flap oxidative stress markers in rats. Also, another effect of NSeO was investigated on the expression of mTOR and p-mTOR.

MATERIALS AND METHODS

Fifty rats were divided into five groups of ten. Skin flap size was 3×8 cm in all groups. Groups were: (1) Sham, (2) Flap Surgery group, (3) Flap Surgery + NSeO, (4) Flap Surgery + Rapamycin (mTOR inhibitor), (5) Flap Surgery + Rapamycin + NSeO. The flap necrosis rate was computed using the paper pattern method on day seven after surgery. After day seven, flap tissues were collected for histological evaluations. Then, malondialdehyde (MDA) content and superoxide dismutase (SOD) activity were measured. Furthermore, the expression levels of mTOR and p-mTOR were measured using the Western blot method.

RESULTS

Treatment with NSeO significantly reduced necrosis (P<0.05). It also resulted in a decrease in MDA level (P<0.05). Histologically, NSeO reduced inflammation and increased positive signs of tissue healing (epithelialization, neovascularization, fibroblast migration, and granulation tissue). NSeO increased SOD activity significantly (P<0.05), whereas, using rapamycin reversed these effects. Also, in all groups, mTOR changes were not significant. Additionally, p-mTOR expression was significantly reduced in groups that rapamycin was injected.

CONCLUSION

NSeO can reduce flap necrosis and enhance tissue healing in rats. So, it can potentially be used clinically to promote tissue repair significantly, and its effects are independent of the mTOR pathway.

NO LEVEL ASSIGNED

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Aloe vera increases collagen fibres in extracellular matrix and mRNA expression of peroxiredoxin-6 in bovine ovarian cortical tissues cultured in vitro

In vitro culture of ovarian tissue containing primordial follicles is an important tool to study the initiation of follicular populations and to develop efficient culture systems to support in vitro follicle growth. Considering that in vitro culture favours oxidative stress, it is very important to supplement culture medium with antioxidant substances such as Aloe vera extract. This study aims to evaluate the effects of different concentrations of Aloe vera on the distribution of collagen fibres in the extracellular matrix, follicular activation, development and survival in bovine ovarian cortical tissues cultured in vitro, as well as on expression of mRNAs for antioxidant enzymes [superoxide dismutase (SOD), catalase (CAT), peroxiredoxin 6 (PRDX6) and glutathione peroxidase 1 (GPX1)]. To this end, ovarian cortical tissues were cultured for 6 days in α-MEM alone or supplemented with different concentrations of Aloe vera extract (1.0, 5.0, 10.0 or 50.0%). After culture, fragments were fixed and processed histologically to evaluate follicular morphology and activation, as well as the extracellular matrix by staining with picrosirius red. The levels of mRNA for SOD, CAT, PRDX6 and GPX1 in cultured ovarian tissues were evaluated by real-time polymerase chain reaction (PCR). Ovarian tissues cultured with 10.0 or 50.0% Aloe vera had higher percentages of collagen fibres than tissues cultured in control medium. A significant increase in developing follicles was observed in ovarian tissues cultured in α-MEM alone or supplemented with 10% Aloe vera when compared with fresh control or tissues cultured with 1.0% Aloe vera. Presence of Aloe vera did not influence the percentage of morphologically normal follicles when compared with control medium. Ovarian tissues cultured with 50.0% Aloe vera had higher percentages of morphologically normal follicles than those cultured with 10.0% Aloe vera. Furthermore, 10% Aloe vera significantly increased mRNA levels for PRDX6. In conclusion, 10.0% Aloe vera improves extracellular matrix distribution in cultured tissues and increases the expression of mRNA for PRDX6 after 6 days in vitro.

The Fibrotic Effects of TMAO on Human Renal Fibroblasts Is Mediated by NLRP3, Caspase-1 and the PERK/Akt/mTOR Pathway

Trimethylamine N-oxide (TMAO), a product of gut microbiota metabolism, has previously been shown to be implicated in chronic kidney disease. A high TMAO-containing diet has been found to cause tubulointerstitial renal fibrosis in mice. However, today there are no data linking specific molecular pathways with the effect of TMAO on human renal fibrosis. The aim of this study was to investigate the fibrotic effects of TMAO on renal fibroblasts and to elucidate the molecular pathways involved. We found that TMAO promoted renal fibroblast activation and fibroblast proliferation via the PERK/Akt/mTOR pathway, NLRP3, and caspase-1 signaling. We also found that TMAO increased the total collagen production from renal fibroblasts via the PERK/Akt/mTOR pathway. However, TMAO did not induce fibronectin or TGF-β1 release from renal fibroblasts. We have unraveled that the PERK/Akt/mTOR pathway, NLRP3, and caspase-1 mediates TMAO’s fibrotic effect on human renal fibroblasts. Our results can pave the way for future research to further clarify the molecular mechanism behind TMAO’s effects and to identify novel therapeutic targets in the context of chronic kidney disease.

Silk Fibroin: A Promising Tool for Wound Healing and Skin Regeneration

Silk is a functional protein biomaterial produced by a variety of insects like flies, silkworms, scorpions, spiders, and mites. Silk synthesized by silkworms is extensively studied for its applications in tissue engineering and wound healing. Silk is undoubtedly a natural biocompatible material with humans and has its role in medical treatments from ancient times. The silk worm protein comprises two types of proteins namely fibroin and sericin. Silk fibroin makes up approximately 70% of cocoon weight and has wide applications in textiles and in all biomedical applications owing to its biocompatible, nontoxic, biodegradable, less immunogenic, and noncarcinogenic nature. It possesses outstanding toughness and mechanical strength, while silk sericin possesses high defensive ability against ultraviolet light and oxidation. Silk fibroin has been known to induce wound healing by increasing cell proliferation and growth and migrating various types of cells which are involved in different stages of wound healing process. With several silk varieties like silk worm fibroin, silk sericin, recombinant silk materials, and native spider silk have been investigated for its wound healing applications over the last several decades. With an objective of harnessing the silk regenerative properties, plentiful strategies have been studied and applied to develop bioartificial skin grafts and bioactive wound dressings in recent times. This review gives a detailed insight into the structure, general properties, fibroin structure-properties relationship, and biomedical applications of silk fibroin.

Electricity auto-generating skin patch promotes wound healing process by activation of mechanosensitive ion channels

Electricity constitutes a natural biophysical component that preserves tissue homeostasis and modulates many biological processes, including the repair of damaged tissues. Wound healing involves intricate cellular events, such as inflammation, angiogenesis, matrix synthesis, and epithelialization whereby multiple cell types sense the environmental cues to rebuild the structure and functions. Here, we report that electricity auto-generating glucose-responsive enzymatic-biofuel-cell (EBC) skin patch stimulates the wound healing process. Rat wounded-skin model and in vitro cell cultures showed that EBC accelerated wound healing by modulating inflammation while stimulating angiogenesis, fibroblast fuctionality and matrix synthesis. Of note, EBC-activated cellular bahaviors were linked to the signalings involved with calcium influx, which predominantly dependent on the mechanosensitive ion channels, primarily Piezo1. Inhibition of Piezo1-receptor impaired the EBC-induced key functions of both fibroblasts and endothelial cells in the wound healing. This study highlights the significant roles of electricity played in wound healing through activated mechanosensitive ion channels and the calcium influx, and suggests the possibility of the electricity auto-generating EBC-based skin patch for use as a wound healing device.

Molecular mechanisms and associated cell signalling pathways underlying the anticancer properties of phytochemical compounds from Aloe species (Review)

Naturally occurring components from various species of Aloe have been used as traditional folk medicine since the ancient times. Over the last few decades, the therapeutic effects of extracts and phytochemical compounds obtained from Aloe vera have been proven in preclinical and clinical studies. Recently, compounds from other Aloe species apart from Aloe vera have been investigated for the treatment of different diseases, with a particular focus on cancer. In the present review, the effects of phytochemical compounds obtained from different Aloe species are discussed, with a specific focus on the effects on cell signalling in cancer and normal cells, and their selectivity and efficacy. This information will be useful for the application of Aloe-derived compounds as therapeutic agents, either alone or in combination with other standard drugs for cancer treatment.

SETD2 epidermal deficiency promotes cutaneous wound healing via activation of AKT/mTOR Signalling

Objectives

Cutaneous wound healing is one of the major medical problems worldwide. Epigenetic modifiers have been identified as important players in skin development, homeostasis and wound repair. SET domain–containing 2 (SETD2) is the only known histone H3K36 tri‐methylase; however, its role in skin wound healing remains unclear.

Materials and Methods

To elucidate the biological role of SETD2 in wound healing, conditional gene targeting was used to generate epidermis‐specific Setd2‐deficient mice. Wound‐healing experiments were performed on the backs of mice, and injured skin tissues were collected and analysed by haematoxylin and eosin (H&E) and immunohistochemical staining. In vitro, CCK8 and scratch wound‐healing assays were performed on Setd2‐knockdown and Setd2‐overexpression human immortalized keratinocyte cell line (HaCaT). In addition, RNA‐seq and H3K36me3 ChIP‐seq analyses were performed to identify the dysregulated genes modulated by SETD2. Finally, the results were validated in functional rescue experiments using AKT and mTOR inhibitors (MK2206 and rapamycin).

Results

Epidermis‐specific Setd2‐deficient mice were successfully established, and SETD2 deficiency resulted in accelerated re‐epithelialization during cutaneous wound healing by promoting keratinocyte proliferation and migration. Furthermore, the loss of SETD2 enhanced the scratch closure and proliferation of keratinocytes in vitro. Mechanistically, the deletion of Setd2 resulted in the activation of AKT/mTOR signalling pathway, while the pharmacological inhibition of AKT and mTOR with MK2206 and rapamycin, respectively, delayed wound closure.

Conclusions

Our results showed that SETD2 loss promoted cutaneous wound healing via the activation of AKT/mTOR signalling.

microRNA-106b derived from endothelial cell-secreted extracellular vesicles prevents skin wound healing by inhibiting JMJD3 and RIPK3

Intriguingly, microRNAs (miRs) transferred as cargo in extracellular vesicles (EVs) can modulate wound healing through their regulation of fibroblast functions. In this study, we investigated the effects of miR‐106b transfer via EVs derived from human umbilical vein endothelial cells (HUVECs) on skin wound healing. Dual‐luciferase reporter gene assay identified that miR‐106b could target and inhibit JMJD3. RT‐qPCR analysis showed EVs isolated from HUVECs had enriched expression of miR‐106b. LL29 fibroblast cells and HaCaT keratinocytes were co‐cultured with HUVEC‐derived EVs, in which miR‐106b had been up‐regulated or down‐regulated by its mimic or inhibitor. The co‐culture with HUVEC‐derived EVs increased miR‐106b expression, and reduced the viability and adhesion of LL29 and HaCaT cells, whereas the inhibition of miR‐106b in HUVEC‐derived EVs enhanced the viability and adhesion of LL29 and HaCaT cells through up‐regulation of JMJD3. Next, we showed that JMJD3 overexpression enhanced LL29 and HaCaT cell viability and adhesion through elevating RIPK3, which induced the phosphorylation of AKT during the wound‐healing process. We next developed a mouse skin wound model to investigate the actions of miR‐106b in vivo after 14 days. The delivery of miR‐106b via HUVEC‐derived EVs delayed wound healing through suppression of collagen I content and angiogenesis, but had no effects on pro‐inflammatory cytokines. In conclusion, miR‐106b from HUVEC‐derived EVs inhibits JMJD3 and RIPK3, leading to the inhibition of skin wound healing, thus constituting a new therapeutic target.

Taurine ameliorates axonal damage in sciatic nerve of diabetic rats and high glucose exposed DRG neuron by PI3K/Akt/mTOR-dependent pathway

Diabetic peripheral neuropathy (DPN) is a common complication of diabetes and axonopathy is its main pathological feature. Previous studies suggested an advantage of taurine against diabetes. However, there are few reports which study the effect of taurine against axonopathy. In this study, we confirmed that taurine significantly decreased blood glucose level, mitigated insulin resistance and improved dysfunctional nerve conduction in diabetic rats. Taurine corrected damaged axonal morphology of sciatic nerve in diabetic rats and induced axon outgrowth of Dorsal root ganglion (DRG) neurons exposed to high glucose. Taurine up-regulated phosphorylation levels of PI3K, Akt, and mTOR in sciatic nerve of diabetic rats and DRG neurons exposed to high glucose. However, Akt and mTOR inhibitors (MK-2206 and Rapamycin) blocked the effect of taurine on improving axonal damage. These results indicate that taurine ameliorates axonal damage in sciatic nerve of diabetic rats by activating PI3K/Akt/mTOR signal pathway. Our findings provide taurine as a potential candidate for axonopathy and a new evidence for elucidating protective mechanism of taurine on DPN.

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.

Infrared-A Irradiation-induced Inhibition of Human Keratinocyte Proliferation and Potential Mechanisms

Infrared-A (IRA), which can penetrate deeply into the human skin, is a major component of solar radiation and is recognized to promote photoaging of human dermis. To our knowledge, however, the cellular and molecular consequences of human epidermis exposure to IRA have not been clarified. Thus, we investigated whether IRA inhibits the proliferation of normal human epidermal keratinocytes (NHEKs). IRA irradiation ed in cell cycle arrest at G1 and a dose-dependent reduction in the proliferation of NHEKs. We found that mechanistic target of rapamycin complex 1 (mTORC1) was initially inactivated during IRA irradiation due to the formation of stress granules (SGs), and this inactivation was maintained for at least 6 h after irradiation due to Akt dephosphorylation. Furthermore, repeated exposure of human skin equivalents to IRA led to marked thinning of the epidermal cell layer. In conclusion, IRA irradiation inhibits mTORC1 activity possibly through two molecular mechanisms involving SG formation in the early-phase and subsequent Akt dephosphorylation. This sequential mechanism seems to cause G1 cell cycle arrest and a reduction in cell proliferation, supporting the hypothesis that the decreased proliferation of basal keratinocytes that occurs during skin aging might be partly attributable to IRA radiation.

Tetrahedral framework nucleic acids promote scarless healing of cutaneous wounds via the AKT-signaling pathway

While the skin is considered the first line of defense in the human body, there are some vulnerabilities that render it susceptible to certain threats, which is an issue that is recognized by both patients and doctors. Cutaneous wound healing is a series of complex processes that involve many types of cells, such as fibroblasts and keratinocytes. This study showed that tetrahedral framework nucleic acids (tFNAs), a type of self-assembled nucleic-acid material, have the ability to promote keratinocyte(HaCaT cell line) and fibroblast(HSF cell line) proliferation and migration in vitro. In addition, tFNAs increased the secretion of vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) in HSF cells and reduced the production of tumor necrosis factor-alpha (TNF-α) and interleukin-1 beta (IL-1β) in HaCaT cells by activating the AKT-signaling pathway. During in vivo experiments, tFNA treatments accelerated the healing process in skin wounds and decreased the development of scars, compared with the control treatment that did not use tFNAs. This is the first study to demonstrate that nanophase materials with the biological features of nucleic acids accelerate the healing of cutaneous wounds and reduce scarring, which indicates the potential application of tFNAs in skin tissue regeneration.

Acemannan Used as an Implantable Biomaterial for Vital Pulp Therapy of Immature Permanent Teeth Induced Continued Root Formation

Direct pulp-capping, a vital pulp therapy, is used to protect and preserve pulp vitality by applying a biomaterial on the pulp exposure site. Acemannan, a polysaccharide extracted from Aloe vera, induces osteodentin-bridge formation to cover the exposure site in vivo. We evaluated the effect of acemannan sponges on partial pulpotomized permanent teeth with caries or accident-induced pulp exposure (n = 50). After removing infected dentin and inflamed pulp tissue, the teeth were randomly divided into acemannan or control (mineral trioxide aggregate (MTA) groups (n = 25). The teeth were examined immediately after treatment (baseline) and at 6- and 12-month follow-ups for clinical and cone beam computed tomography (CBCT) examination. The three-dimensional tooth length and root apex area were simulated to determine treatment success. We found that the overall success rate in the acemannan and MTA groups from baseline to 12-month follow-up was 90.91% and 95.65%, respectively, with no significant difference between the two groups (p > 0.05). In the success teeth in both groups, the root length increased, and the apex area significantly decreased (p < 0.05), indicating continued root formation. Our results suggest that acemannan is a promising low-cost biomaterial for partial pulpotomy treatment for immature permanent teeth requiring vital pulp therapy.

Evaluation of wound healing effect of alginate film containing Aloe vera gel and cross-linked with zinc chloride

PURPOSE

To develop a new wound dressing composed of alginate and Aloe vera gel and cross-linked with zinc ions.

METHODS

The aloe-alginate film was characterized using scanning electron microscopy (SEM), swelling profile, mechanical properties, polysaccharide content and X-ray diffraction (XRD). Thirty Wistar rats were divided in two groups a) treated with aloe-alginate film and b) control (treated with sterile gauze). Wound contraction measurements and hystological analysis were performed on 7th, 14th and 21st days after wound surgery.

RESULTS

The aloe-alginate film presented adequated mechanical resistance and malleability for application as wound dressing. There was no statistical difference in wound contraction between two groups. Histological assay demonstrated that aloe-alginate film presented anti-inflammatory activity, stimulated angiogenesis on proliferative phase and a more significant increased in collagen type I fibers and decreased type III fibers which promoted a mature scar formation when compared to control.

CONCLUSIONS

The aloe-alginate film showed adequate physicochemical characteristics for wound dressing applications. The in vivo assay demonstrated that aloe-alginate film enhanced the healing process of incisional skin wounds.

A liposome/gelatin methacrylate nanocomposite hydrogel system for delivery of stromal cell-derived factor-1α and stimulation of cell migration

Chronic, non-healing skin and soft tissue wounds are susceptible to infection, difficult to treat clinically, and can severely reduce a patient's quality of life. A key aspect of this issue is the impaired recruitment of mesenchymal stem cells (MSCs), which secrete regenerative cytokines and modulate the phenotypes of other effector cells that promote healing. We have engineered a therapeutic delivery system that can controllably release the pro-healing chemokine stromal cell derived factor-1α (SDF-1α) to induce the migration of MSCs. In order to protect the protein cargo from hydrolytic degradation and control its release, we have loaded SDF-1α in anionic liposomes (lipoSDF) and embedded them in gelatin methacrylate (GelMA) to form a nanocomposite hydrogel. In this study, we quantify the release of SDF-1α from our hydrogel system and measure the induced migration of MSCs in vitro via a transwell assay. Lastly, we evaluate the ability of this system to activate intracellular signaling in MSCs by using Western blots to probe for the phosphorylation of key proteins in the mTOR pathway. To our knowledge, this is the first study to report the delivery of liposomal SDF-1α using a nanocomposite approach. The results of this study expand on our current understanding of factors that can be modified to affect MSC behavior and phenotype. Furthermore, our findings contribute to the development of new hydrogel-based therapeutic delivery strategies for clinical wound healing applications. STATEMENT OF SIGNIFICANCE: Chronic, non-healing wounds promote an inflammatory environment that inhibits the migration of mesenchymal stem cells (MSCs), which secrete pro-healing and regenerative cytokines. The goal of this project is to apply principles of tissue engineering to achieve controllable release of the pro-healing chemokine SDF-1α to modulate the intracellular signaling and migratory behavior of MSCs. In this work, we introduce a nanocomposite strategy to tailor the release of SDF-1α using a liposome/gelatin methacrylate hydrogel approach. We are the first group to report the delivery of liposomal SDF-1α using this strategy. Our findings aim to further elucidate the role of MSCs in directing wound healing and guide the development of immunomodulatory and therapeutic delivery strategies for clinical wound healing applications.

Preparation and bioactivity of acetylated konjac glucomannan fibrous membrane and its application for wound dressing

Biomaterial-host interactions significantly affect tissue repair, which is modulated by macrophages. In this study, a polysaccharide, konjac glucomannan (KGM), was acetylated with different degrees of substitution (DS), and the acetylated KGM (AceKGM)-based fibrous membrane was designed to modulate the activity of macrophages for accelerating wound healing. AceKGM was biocompatible and easily dissolved in organic solvents. The adhesion force between Raw264.7 cells and the AceKGM substrate was quantitatively detected by atomic force microscopy (AFM). The enzyme-linked immunosorbent assay (ELISA) results showed that the AceKGM fibrous membrane enhanced macrophage expression of anti-inflammatory and pro-regenerative cytokines, and the DS of AceKGM significantly affected membrane bioactivity. The full-thickness mouse skin wound repair experiments indicated that the AceKGM-containing fibrous membranes significantly accelerated wound healing by promoting re-epithelialization, tissue remodeling, and collagen deposition. In summary, AceKGM-based fibrous membranes have potential as bioactive scaffolds for wound regeneration.

Wound Healing and the Use of Medicinal Plants

Cutaneous wound healing is the process by which skin repairs itself. It is generally accepted that cutaneous wound healing can be divided into 4 phases: haemostasis, inflammation, proliferation, and remodelling. In humans, keratinocytes re-form a functional epidermis (reepithelialization) as rapidly as possible, closing the wound and reestablishing tissue homeostasis. Dermal fibroblasts migrate into the wound bed and proliferate, creating “granulation tissue” rich in extracellular matrix proteins and supporting the growth of new blood vessels. Ultimately, this is remodelled over an extended period, returning the injured tissue to a state similar to that before injury. Dysregulation in any phase of the wound healing cascade delays healing and may result in various skin pathologies, including nonhealing, or chronic ulceration. Indigenous and traditional medicines make extensive use of natural products and derivatives of natural products and provide more than half of all medicines consumed today throughout the world. Recognising the important role traditional medicine continues to play, we have undertaken an extensive survey of literature reporting the use of medical plants and plant-based products for cutaneous wounds. We describe the active ingredients, bioactivities, clinical uses, formulations, methods of preparation, and clinical value of 36 medical plant species. Several species stand out, including Centella asiatica, Curcuma longa, and Paeonia suffruticosa, which are popular wound healing products used by several cultures and ethnic groups. The popularity and evidence of continued use clearly indicates that there are still lessons to be learned from traditional practices. Hidden in the myriad of natural products and derivatives from natural products are undescribed reagents, unexplored combinations, and adjunct compounds that could have a place in the contemporary therapeutic inventory.

Detection of Seasonal Variation in Aloe Polysaccharides Using Carbohydrate Detecting Microarrays

Aloe vera gel is a globally popular natural product used for the treatment of skin conditions. Its useful properties are attributed to the presence of bioactive polysaccharides. Nearly 25% of the 600 species in the genus Aloe are used locally in traditional medicine, indicating that the bioactive components in Aloe vera may be common across the genus Aloe. The complexity of the polysaccharides has hindered development of relevant assays for authentication of Aloe products. Carbohydrate detecting microarrays have recently been suggested as a method for profiling Aloe polysaccharide composition. The aim of this study was to use carbohydrate detecting microarrays to investigate the seasonal variation in the polysaccharide composition of two medicinal and two non-medicinal Aloe species over the course of a year. Microscopy was used to explore where in the cells the bioactive polysaccharides are present and predict their functional role in the cell wall structure. The carbohydrate detecting microarrays analyses showed distinctive differences in the polysaccharide composition between the different species and carbohydrate detecting microarrays therefore has potential as a complementary screening method directly targeting the presence and composition of relevant polysaccharides. The results also show changes in the polysaccharide composition over the year within the investigated species, which may be of importance for commercial growing in optimizing harvest times to obtain higher yield of relevant polysaccharides.

Extraction, Purification, Structural Characteristics, Biological Activities and Pharmacological Applications of Acemannan, a Polysaccharide from Aloe vera: A Review

Aloe vera is a medicinal plant species of the genus Aloe with a long history of usage around the world. Acemannan, considered one of the main bioactive polysaccharides of Aloe vera, possesses immunoregulation, anti-cancer, anti-oxidation, wound healing and bone proliferation promotion, neuroprotection, and intestinal health promotion activities, among others. In this review, recent advancements in the extraction, purification, structural characteristics and biological activities of acemannan from Aloe vera were summarized. Among these advancements, the structural characteristics of purified polysaccharides were reviewed in detail. Meanwhile, the biological activities of acemannan from Aloe vera determined by in vivo, in vitro and clinical experiments are summarized, and possible mechanisms of these bioactivities were discussed. Moreover, the latest research progress on the use of acemannan in dentistry and wound healing was also summarized in details. The structure-activity relationships of acemannan and its medical applications were discussed. Finally, new perspectives for future research work on acemannan were proposed. In conclusion, this review summarizes the extraction, purification, structural characteristics, biological activities and pharmacological applications of acemannan, and provides information for the industrial production and possible applications in dentistry and wound healing in the future.

Photocrosslinked acemannan-based 3D matrices for in vitro cell culture

Photocrosslinking on acemannan is proposed as a green approach for the production of high added-value acemannan structures, enabling its biomedical exploitation.

Therapeutic Effects of Medicinal Plants on Cutaneous Wound Healing in Humans: A Systematic Review

The pharmaceutical industry has made great strides in providing drugs that are able to stimulate the healing process, but only 1-3% of all drugs that are listed in Western pharmacopoeias are intended for use on the skin or cutaneous wounds. Of these, at least one-third are obtained from plants. We sought to review the therapeutic effects of medicinal plants on human skin lesions. For this systematic review, we searched the PubMed, Scopus, and Web of Science databases to identify clinical trials that were published from 1997 to 2017. We reviewed studies that described the use of medicinal plants for the treatment of skin lesions in humans. Ten studies were selected, eight of which were published from 2007 to 2016, with a total of 503 patients. Among the plant species that were used for the treatment of human skin lesions, 12 belonged to 11 families and were included in the analysis. All of the plant species that were studied presented high therapeutic potential for the treatment of cutaneous lesions.

NF-κB signaling is key in the wound healing processes of silk fibroin

Silk fibroin (SF) is a well-studied biomaterial for tissue engineering applications including wound healing. However, the signaling mechanisms underlying the impact of SF on this phenomenon have not been determined. In this study, through microarray analysis, regulatory genes of NF-ĸB signaling were activated in SF-treated NIH3T3 cells along with other genes. Immunoblot analysis confirmed the activation of the NF-ĸB signaling pathway as SF induced protein expression levels of IKKα, IKKβ, p65, and the degradation of IκBα. The treatment of NIH3T3 cells with SF also increased the expression of cyclin D1, vimentin, fibronectin, and vascular endothelial growth factor (VEGF). The expression of these factors by SF treatment was abrogated when NF-ĸB was inhibited by a pharmacological inhibitor Bay 11-7082. Knockdown of NF-ĸB using siRNA of IKKα and IKKβ also inhibited the SF-induced wound healing response of the NIH3T3 cells in a wound scratch assay. Collectively, these results indicated that SF-induced wound healing through the canonical NF-κB signaling pathway via regulation of the expression of cyclin D1, vimentin, fibronectin, and VEGF by NIH3T3 cells. Using an in vivo study with a partial-thickness excision wound in rats we demonstrated that SF-induced wound healing via NF-κB regulated proteins including cyclin D1, fibronectin, and VEGF. The in vitro and in vivo data suggested that SF induced wound healing via modulation of NF-ĸB signaling regulated proteins.

STATEMENT OF SIGNIFICANCE

Silk fibroin has been effectively used as a dressing for wound treatment for more than a century. However, mechanistic insight into the basis for wound healing via silk fibroin has not been elucidated. Here we report a key mechanism involved in silk fibroin induced wound healing both in vitro and in vivo. Using genetic- and protein-level analyses, NF-κB signaling was found to regulate silk fibroin-induced wound healing by modulating target proteins. Thus, the NF-κB signaling pathway may be utilized as a therapeutic target during the formulation of silk fibroin-based biomaterials for wound healing and tissue engineering.