Epidermal growth factor-containing wound closure enhances wound healing in non-diabetic and diabetic rats

Curcumin-Polyethylene Glycol Loaded on Chitosan-Gelatin Nanoparticles Enhances Infected Wound Healing

The aim of the present study was to evaluate effects of curcumin-polyethylene glycol loaded on chitosan-gelatin nanoparticles (C-PEG-CGNPs) on healing of methicillin-resistant Staphylococcus aureus (MRSA)-infected wounds in rat as a model study. Forty male Wistar rats were randomized into 5 groups of 8 animals each. In CNTRL group, no infected/no treated wounds were covered with sterile saline 0.9% solution (0.1 mL). In MRSA group, MRSA-infected wounds were only treated with sterile saline 0.9% solution (0.1 mL). In MRSA/CP group, 0.1 mL curcumin nanoparticles (1 mg/mL) was applied topically to treat MRSA-infected wounds. In MRSA/CG group, 0.1 mL CG (1 mg/mL) was applied topically to treat MRSA-infected wounds. In MRSA/CP-CG group, 0.1 mL CP-CG (1 mg/mL) was applied topically to treat MRSA-infected wounds. Microbiological examination; planimetric, biochemical, histological, morphometric studies, angiogenesis, hydroxyproline levels, and reverse transcription polymerase chain reaction for caspase 3, Bcl-2, and p53 showed significant difference between rats in MRSA/CP-CG group in comparison with other groups (P < .05). Accelerated and improved healing in wounds infected with MRSA were observed in animals treated with C-PEG-CGNPs. Via increasing solubility of curcumin in C-PEG-CGNP, this harmless and easily available composition could be considered to be topically applied in infected wounds.

Combination of Pinocembrin and Epidermal Growth Factor Enhances the Proliferation and Survival of Human Keratinocytes

Re-epithelialization is delayed in aged skin due to a slow rate of keratinocyte proliferation, and this may cause complications. Thus, there has been development of new therapies that increase treatment efficacy for skin wounds. Epidermal growth factor (EGF) has been clinically used, but this agent is expensive, and its activity is less stable. Therefore, a stable compound possessing EGF-like properties may be an effective therapy, especially when combined with EGF. The current study discovered that pinocembrin (PC) effectively synergized with EGF in increasing keratinocyte viability. The combination of PC and EGF significantly enhanced the proliferation and wound closure rate of the keratinocyte monolayer through activating the phosphorylation of ERK and Akt. Although these effects of PC were like those of EGF, we clearly proved that PC did not transactivate EGFR. Recent data from a previous study revealed that PC activates G-protein-coupled receptor 120 which further activates ERK1/2 and Akt phosphorylation. Therefore, this clearly indicates that PC possesses a unique property to stimulate the growth and survival of keratinocytes through activating a different receptor, which subsequently conveys the signal to cross-talk with the effector kinases downstream of the EGFR, suggesting that PC is a potential compound to be combined with EGF.

In Vitro and In Vivo Evaluation of Epidermal Growth Factor (EGF) Loaded Alginate-Hyaluronic Acid (AlgHA) Microbeads System for Wound Healing

The management of skin injuries is one of the most common concerns in medical facilities. Different types of biomaterials with effective wound-healing characteristics have been studied previously. In this study, we used alginate (Alg) and hyaluronic acid (HA) composite (80:20) beads for the sustained release of epidermal growth factor (EGF) delivery. Heparin crosslinked AlgHA beads showed significant loading and entrapment of EGF. Encapsulated beads demonstrated biocompatibility with rat L929 cells and significant migration at the concentration of AlgHAEGF100 and AlgHAEGF150 within 24 h. Both groups significantly improved the expression of Fetal Liver Kinase 1 (FLK-1) along with the Intercellular Adhesion Molecule-1 (ICAM-1) protein in rat bone Mesenchymal stem cells (rbMSCs). In vivo assessment exhibited significant epithelialization and wound closure gaps within 2 weeks. Immunohistochemistry shows markedly significant levels of ICAM-1, FLK-1, and fibronectin (FN) in the AlgHAEGF100 and AlgHAEGF150 groups. Hence, we conclude that the EGF-loaded alginate-hyaluronic acid (AlgHA) bead system can be used to promote wound healing.

Therapeutic role of growth factors in treating diabetic wound

Wounds in diabetic patients, especially diabetic foot ulcers, are more difficult to heal compared with normal wounds and can easily deteriorate, leading to amputation. Common treatments cannot heal diabetic wounds or control their many complications. Growth factors are found to play important roles in regulating complex diabetic wound healing. Different growth factors such as transforming growth factor beta 1, insulin-like growth factor, and vascular endothelial growth factor play different roles in diabetic wound healing. This implies that a therapeutic modality modulating different growth factors to suit wound healing can significantly improve the treatment of diabetic wounds. Further, some current treatments have been shown to promote the healing of diabetic wounds by modulating specific growth factors. The purpose of this study was to discuss the role played by each growth factor in therapeutic approaches so as to stimulate further therapeutic thinking.

Wound healing activity of Salvia huberi ethanolic extract in streptozocin-induced diabetic rats

Objective: The aim of this study was to examine the in vivo wound healing potential of Salvia huberi Hedge (endemic to Turkey) on excision and incision wound models in diabetic rats. Method: Male Wistar albino rats, 3-4 months old and weighing 180-240g were used. The animals were randomly divided into five groups including Control, Vehicle and Fito reference, and two different concentrations (0.5% and 1% weight/weight (w/w)) of ethanol extract of Salvia huberi were investigated in both wound models on streptozocin-induced diabetic rats using macroscopic, biomechanical, biochemical, histopathological, genotoxic and gene expression methods over both seven and 14 days. Fito cream (Tripharma Drug Industry and Trade Inc., Turkey) was used as the reference drug. Results: A total of 60 rats were used in this study. Salvia huberi ointments at 0.5% and 1% (w/w) concentrations and Fito cream showed 99.3%, 99.4% and 99.1% contraction for excision wounds, and 99.9%, 97.0% and 99% contraction for incision wounds, respectively. In Salvia huberi ointments and Fito cream groups, re-epithelialisation increased dramatically by both day 7 and day 14 (p<0.05). By day 14, low hydroxyproline and malondialdehyde (MDA) levels, and high glutathione (GSH) levels were observed in the Salvia huberi ointment groups. After two application periods, damaged cell percent and genetic damage index values and micronucleus frequency of Salvia huberi ointment treatment groups were lower than Control and Vehicle groups (p<0.001). A growth factor expression reached a high level by day 7 in the Control group; in Salvia huberi-treated groups it was decreased. Conclusion: The study showed that application of Salvia huberi ointments ameliorated the healing process in diabetic rats with excisional and incisional wounds and may serve as a potent healing agent.

Wound healing activity of Salvia huberi ethanolic extract in streptozocin-induced diabetic rats

Objective: The aim of this study was to examine the in vivo wound healing potential of Salvia huberi Hedge (endemic to Turkey) on excision and incision wound models in diabetic rats. Method: Male Wistar albino rats, 3-4 months old and weighing 180-240g were used. The animals were randomly divided into five groups including Control, Vehicle and Fito reference, and two different concentrations (0.5% and 1% weight/weight (w/w)) of ethanol extract of Salvia huberi were investigated in both wound models on streptozocin-induced diabetic rats using macroscopic, biomechanical, biochemical, histopathological, genotoxic and gene expression methods over both seven and 14 days. Fito cream (Tripharma Drug Industry and Trade Inc., Turkey) was used as the reference drug. Results: A total of 60 rats were used in this study. Salvia huberi ointments at 0.5% and 1% (w/w) concentrations and Fito cream showed 99.3%, 99.4% and 99.1% contraction for excision wounds, and 99.9%, 97.0% and 99% contraction for incision wounds, respectively. In Salvia huberi ointments and Fito cream groups, re-epithelialisation increased dramatically by both day 7 and day 14 (p<0.05). By day 14, low hydroxyproline and malondialdehyde (MDA) levels, and high glutathione (GSH) levels were observed in the Salvia huberi ointment groups. After two application periods, damaged cell percent and genetic damage index values and micronucleus frequency of Salvia huberi ointment treatment groups were lower than Control and Vehicle groups (p<0.001). A growth factor expression reached a high level by day 7 in the Control group; in Salvia huberi-treated groups it was decreased. Conclusion: The study showed that application of Salvia huberi ointments ameliorated the healing process in diabetic rats with excisional and incisional wounds and may serve as a potent healing agent.

Herbal Products and Their Active Constituents for Diabetic Wound Healing-Preclinical and Clinical Studies: A Systematic Review

The purpose of this review is to provide verified data on the current knowledge acquired in preclinical and clinical studies regarding topically used herbal products and their active constituents (formulations and dressings) with diabetic wound healing activity. Moreover, herbal products and their active constituents used for diabetic wound infections, and various cellular and molecular mechanisms of their actions will also be described. The electronic databases were searched for articles published from 2012 to 2022. Publications with oral or systemic administration of herbal products in diabetic wound healing, published before 2012, available only as an abstract, or in languages other than English were excluded from the study. The 59 articles comparing topically used herbal products in diabetic wound healing treatment versus control treatments (placebo or active therapy) were selected. Herbal products through different mechanisms of action, including antimicrobial, anti-inflammatory, antioxidant activity, stimulation of angiogenesis, production of cytokines and growth factors, keratinocytes, and fibroblast migration and proliferation may be considered as an important support during conventional therapy or even as a substitute for synthetic drugs used for diabetic wound treatment.

The use of epidermal growth factor in dermatological practice

Epidermal growth factor (EGF) is a growth factor that plays a pivotal role in wound healing and maintaining tissue homeostasis by regulating cell survival, proliferation, migration, and differentiation. Exogenous administration of bioidentical human recombinant epidermal growth factor (rhEGF) has been known to promote skin wound healing, although rhEGF is increasingly being used in drug delivery systems and nanotechnology. However, despite considerable attention being focused on the potential clinical applications of rhEGF in several dermatological conditions beyond wound healing, the number of studies still remains relatively low. Herein, we conducted a literature search of PubMed/Medline and Google Scholar databases to retrieve published literature related to rhEGF and summarised the effects of rhEGF in the treatment of various wound types, radiotherapy or chemotherapy-related skin reactions, atopic dermatitis, skin aging, and post-inflammatory hyperpigmentation.

Growth Factor and Cytokine Delivery Systems for Wound Healing

Skin wound healing is a highly coordinated process involving multiple tissue-resident and recruited cell types. Cells within the wound microenvironment respond to key secreted factors such as pro-proliferative growth factors and immunomodulatory cytokines to repair the skin and promptly restore its essential barrier role. Therefore, recombinant growth factors and cytokines are promising therapeutics for skin wounds, in particular for large acute wounds such as burns, or wounds associated with underlying pathologies such as nonhealing chronic and diabetic wounds. However, translation of growth factors and cytokines into clinically effective treatments has been limited. Short half-life, poor stability, rapid diffusion, uncontrolled signaling, and systemic side effects are currently the key challenges to developing efficient growth factor- and cytokine-based therapies. To overcome these limitations, novel delivery systems have been developed to improve the regenerative potential of recombinant growth factors and cytokines. In this review, we discuss biomaterial and protein engineering strategies used to optimize the delivery of growth factor and cytokine therapeutics for skin wound treatment.

Biomaterials-Based Regenerative Strategies for Skin Tissue Wound Healing

Skin tissue wound healing proceeds through four major stages, including hematoma formation, inflammation, and neo-tissue formation, and culminates with tissue remodeling. These four steps significantly overlap with each other and are aided by various factors such as cells, cytokines (both anti- and pro-inflammatory), and growth factors that aid in the neo-tissue formation. In all these stages, advanced biomaterials provide several functional advantages, such as removing wound exudates, providing cover, transporting oxygen to the wound site, and preventing infection from microbes. In addition, advanced biomaterials serve as vehicles to carry proteins/drug molecules/growth factors and/or antimicrobial agents to the target wound site. In this review, we report recent advancements in biomaterials-based regenerative strategies that augment the skin tissue wound healing process. In conjunction with other medical sciences, designing nanoengineered biomaterials is gaining significant attention for providing numerous functionalities to trigger wound repair. In this regard, we highlight the advent of nanomaterial-based constructs for wound healing, especially those that are being evaluated in clinical settings. Herein, we also emphasize the competence and versatility of the three-dimensional (3D) bioprinting technique for advanced wound management. Finally, we discuss the challenges and clinical perspective of various biomaterial-based wound dressings, along with prospective future directions. With regenerative strategies that utilize a cocktail of cell sources, antimicrobial agents, drugs, and/or growth factors, it is expected that significant patient-specific strategies will be developed in the near future, resulting in complete wound healing with no scar tissue formation.

Review of technology and materials for the development of cultured meat

Cultured meat production technology suggested that can solve the problems of traditional meat production such as inadequate breeding environment, wastewater, methane gas generation, and animal ethics issues. Complementing cultured meat production methods, sales and safety concerns will make the use of cultured meat technology easier. This review contextualizes the commercialization status of cultured meat and the latest technologies and challenges associated with its production. Investigation was conducted on materials and basic cell culture technique for cultured meat culture is presented. The development of optimal cultured meat technology through these studies will be an innovative leap in food technology. The process of obtaining cells from animal muscle, culturing cells, and growing cells into meat are the basic processes of cultured meat production. The substances needed to production of cultured meat were antibiotics, digestive enzymes, basal media, serum or growth factors. Although muscle cells have been produced closer to meat due to the application of scaffolds materials and 3 D printing technology, still a limit to reducing production costs enough to be used as foods. In addition, developing edible materials is also a challenge because the materials used to produce cultured meat are still not suitable for food sources.

Accelerative Effect of Cinnamon Nanoparticles as well as HAMLET on Healing of Wounds Infected with MRSA in Diabetic Rats

Objective

The aim of the present study was to investigate the effect of cinnamon nanoparticles (CNPs) on healing of wounds infected with methicillin-resistant Staphylococcus aurous with human alpha-lactalbumin made lethal to tumor cells sensitization in diabetic rats.

Methods

We included fifty diabetic male rats and divided them into 5 groups. There were 10 rats in each group as follows: CONTROL group: we did not infect the CONTROL group. The wound was only covered with sterile saline 0.9% solution (0.1 mL). INFCTD group: in this group, the wounds were infected with MRSA and covered with sterile saline 0.9% solution (0.1 mL). INFCTD-HMLT group: in this group, the wounds were infected with MRSA and HAMLET (100 μg). INFCTD-CNM group: in this group, the wounds were infected with MRSA and 0.1 mL CNPs (1 mg/mL) were applied topically to wounds. INFCTD-HMLT-CNM group: in this group, the wounds were infected with MRSA, HAMLET (100 μg), and 0.1 mL CNPs (1 mg/mL).

Results

Bacteriology, wound area reduction measurements, biochemistry, histomorphometrical studies, hydroxyproline levels, and reverse transcription polymerase chain reaction for caspase-3, Bcl-2, and p53 showed significant difference between rats in the INFCTD-HMT-CNM group in comparison with other groups (P < 0.05).

Conclusions

Accelerated healing of diabetic wounds infected with MRSA showed that local application of cinnamon nanoparticles along with HAMLET sensitization on S. aureus-infected wound could be taken into consideration.

Assessment of wound healing efficacy of Growth Factor Concentrate (GFC) in non-diabetic and diabetic Sprague Dawley rats

Backgrounds

The investigation of wound healing potential of human GFC (growth factor concentrate) was undertaken in diabetic and non-diabetic rats. Primarily, GFC is the combination of several growth factors present in blood which has potential of wound healing. In present study, WCK-GFC kit, a single step optimized kit was used for obtaining human GFC.

Methods

Diabetes in rats was induced by intraperitoneal single injection of 40 mg/kg streptozotocin (STZ). The full thickness circular wounds of 2 cm² area were created using sterilized stainless steel biopsy punch. Non-diabetic wounds were topically treated with 100µL and 300µL of GFC, while diabetic wounds were treated with 300µL of GFC. The standard of care treatment groups were included, wherein the non-diabetic and diabetic wound were topically treated with Nadoxin and Z-AD-G skin cream, respectively. The percentage of wound contraction was measured on weekly intervals. At the end of study duration, tissues from wound were collected for histopathological evaluation.

Results

Both diabetic and non-diabetic GFC treated rats exhibited a significantly higher rate of wound contraction on day 8 and 15 compared to normal untreated control group and standard-of-care treated rats. Wound healing was induced by GFC through rapid re-epithelialization. On comparing wound healing with standard-of care agent, the GFC treated wounds demonstrated a faster remodeling phase, a better organization and lower inflammation.

Conclusions

The current study demonstrates that topically applied GFC promotes healing of wounds, with enhanced wound contraction in both non-diabetic and diabetic rats.

Advancements in the Delivery of Growth Factors and Cytokines for the Treatment of Cutaneous Wound Indications

Significance: Wound healing involves the phasic production of growth factors (GFs) and cytokines to progress an acute wound to a resolved scar. Dysregulation of these proteins contributes to both wound chronicity and excessive scarring. Direct supplementation of GFs and cytokines for treatment of healing and scarring complications has, however, been disappointing. Failings likely relate to an inability to deliver recombinant proteins at physiologically relevant levels to an environment conducive to healing. Recent Advances: Inspired by the extracellular matrix, natural biomaterials have been developed that resemble human skin, and are capable of delivering bioactives. Hybrid biomaterials made using multiple polymers, fabrication methods, and proteins are proving efficacious in animal models of acute and impaired wound healing. Critical Issues: For clinical translation, these delivery systems must be tailored for specific wound indications and the correct phase of healing. GFs and cytokines must be delivered in a controlled manner that will target specific healing or scarring impairments. Preclinical assessment in clinically relevant animal models of impaired or excessive healing is critical. Future Directions: Clinical success will likely depend on the GF or cytokine selected, their compatibility with the chosen biomaterial(s), degradation rate of the fabricated system, and the degree of control over release kinetics. Further testing is essential to assess which wound indications are most suited to specific delivery systems and to prove whether they provide superior efficacy over direct protein therapies.

Growth Factors, Reactive Oxygen Species, and Metformin-Promoters of the Wound Healing Process in Burns?

Burns can be caused by various factors and have an increased risk of infection that can seriously delay the wound healing process. Chronic wounds caused by burns represent a major health problem. Wound healing is a complex process, orchestrated by cytokines, growth factors, prostaglandins, free radicals, clotting factors, and nitric oxide. Growth factors released during this process are involved in cell growth, proliferation, migration, and differentiation. Reactive oxygen species are released in acute and chronic burn injuries and play key roles in healing and regeneration. The main aim of this review is to present the roles of growth factors, reactive oxygen species, and metformin in the healing process of burn injuries.

Limited Treatment Options for Diabetic Wounds: Barriers to Clinical Translation Despite Therapeutic Success in Murine Models

Significance: Millions of people worldwide suffer from diabetes mellitus and its complications, including chronic diabetic wounds. To date, there are few widely successful clinical therapies specific to diabetic wounds beyond general wound care, despite the vast number of scientific discoveries in the pathogenesis of defective healing in diabetes. Recent Advances: In recent years, murine animal models of diabetes have enabled the investigation of many possible therapeutics for diabetic wound care. These include specific cell types, growth factors, cytokines, peptides, small molecules, plant extracts, microRNAs, extracellular vesicles, novel wound dressings, mechanical interventions, bioengineered materials, and more. Critical Issues: Despite many research discoveries, few have been translated from their success in murine models to clinical use in humans. This massive gap between bench discovery and bedside application begs the simple and critical question: what is still missing? The complexity and multiplicity of the diabetic wound makes it an immensely challenging therapeutic target, and this lopsided progress highlights the need for new methods to overcome the bench-to-bedside barrier. How can laboratory discoveries in animal models be effectively translated to novel clinical therapies for human patients? Future Directions: As research continues to decipher deficient healing in diabetes, new approaches and considerations are required to ensure that these discoveries can become translational, clinically usable therapies. Clinical progress requires the development of new, more accurate models of the human disease state, multifaceted investigations that address multiple critical components in wound repair, and more innovative research strategies that harness both the existing knowledge and the potential of new advances across disciplines.

Indentation Stiffness Measurement by an Optical Coherence Tomography-Based Air-Jet Indentation System Can Reflect Type I Collagen Abundance and Organisation in Diabetic Wounds

There is a lack of quantitative and non-invasive clinical biomechanical assessment tools for diabetic foot ulcers. Our previous study reported that the indentation stiffness measured by an optical coherence tomography-based air-jet indentation system in a non-contact and non-invasive manner may reflect the tensile properties of diabetic wounds. As the tensile properties are known to be contributed by type I collagen, this study was aimed to establish the correlations between the indentation stiffness, and type I collagen abundance and organisation, in order to further justify and characterise the in vivo indentation stiffness measurement in diabetic wounds. In a male streptozotocin-induced diabetic rat model, indentation stiffness, and type I collagen abundance and organisation of excisional wounds were quantified and examined using the optical coherence tomography-based air-jet indentation system and picrosirius red polarised light microscopy, respectively, on post-wounding days 3, 5, 7, 10, 14, and 21. The results showed significant negative correlations between indentation stiffness at the wound centre, and the collagen abundance and organisation. The correlations between the indentation stiffness, as well as collagen abundance and organisation of diabetic wounds suggest that the optical coherence tomography-based air-jet indentation system can potentially be used to quantitatively and non-invasively monitor diabetic wound healing in clinical settings, clinical research or preclinical research.

Development of stabilized dual growth factor-loaded hyaluronate collagen dressing matrix

Patients with diabetes experience impaired growth factor production such as epidermal growth factor (EGF) and basic fibroblast growth factor (bFGF), and they are reportedly involved in wound healing processes. Here, we report dual growth factor-loaded hyaluronate collagen dressing (Dual-HCD) matrix, using different ratios of the concentration of stabilized growth factors—stabilized-EGF (S-EGF) and stabilized-bFGF (S-bFGF). At first, the optimal concentration ratio of S-EGF to S-bFGF in the Dual-HCD matrix is determined to be 1:2 in type I diabetic mice. This Dual-HCD matrix does not cause cytotoxicity and can be used in vivo. The wound-healing effect of this matrix is confirmed in type II diabetic mice. Dual HCD enhances angiogenesis which promotes wound healing and thus, it shows a significantly greater synergistic effect than the HCD matrix loaded with a single growth factor. Overall, we conclude that the Dual-HCD matrix represents an effective therapeutic agent for impaired diabetic wound healing.

A Randomized Controlled Trial on the Effectiveness of Epidermal Growth Factor-Containing Ointment on the Treatment of Solar Lentigines as Adjuvant Therapy

Background and Objective: Little is known about the anti-pigmentation effects of whitening agents on solar lentigines. Epidermal growth factor (EGF) has been used as a booster for wound healing in the skin, and it has been suggested to have anti-pigmentation effects. This study aimed to evaluate the effect and safety of EGF-containing ointment for treating solar lentigines with a Q-switched (QS) 532 nm neodymium-doped yttrium aluminum garnet (Nd:YAG) laser (Bluecore company, Seoul, Republic of Korea). Materials and Methods: Subjects who underwent QS 532 nm Nd:YAG laser treatment of solar lentigines were randomly assigned to treatment with an EGF ointment or petrolatum. After the laser procedure, the subjects were administered the test ointment twice a day for 4 weeks. The physician's assessment of the degree of pigment clearance and patient's satisfaction were assessed after 4 and 8 weeks. Additionally, the melanin index (MI), erythema index (EI), transepidermal water loss (TEWL), and post-inflammatory hyperpigmentation (PIH) were evaluated. This trial was registered with ClinicalTrials.gov (NCT04704245). Results: The blinded physician's assessment using 5-grade percentage improvement scale and patient's satisfaction were significantly higher in the study group than in the control group at the 4th and 8th weeks. The MI was significantly higher in the control group than in the study group at the 4th and 8th weeks. The EI and TEWL did not differ significantly between the two groups at either time point. The incidence of PIH was higher in the control group (37.5%) than in the EGF group (7.14%) at the 8th week. Conclusions: The application of EGF-containing ointment on facial solar lentigines with a QS 532 nm Nd:YAG laser showed efficient and safe therapeutic effects, with less PIH. Thus, EGF-containing ointment could be suggested as the promising adjuvant treatment strategy with a QS laser for solar lentigines.

Botrops derived hemocoagulase formulation a probable agent for diabetic wound healing

Botroclot is a marketed preparation containing hemocoagulase, which is an enzyme having coagulant activity, isolated from the snake Botrops atrox. This formulation is used in dental surgeries and other minor surgical wounds. However, the formulation remains untested in diabetic wounds. Hence, we proposed a study for the topical application of Botroclot in high-fat diet (HFD) + Streptozotocin (STZ) induced diabetic rats. HFD was fed initially to rats which facilitates the development of insulin resistance. Thereafter, an injection of STZ (40 mg/kg, i.p.) was given. This resulted in the development of diabetes with elevated fasting glucose and impaired glucose tolerance. After stabilization of blood glucose values, wounds were created by punch biopsy on the dorsal side of the palm of the rat to mimic the diabetic wounds frequently seen in the case of humans. Later, the application of Botroclot on these wounds was carried out for 15 days. Topical application of hemocoagulase improved the wound closure and there was a gradual decrease in inflammatory markers and a substantial increase in collagen deposition occurred. Histopathological findings indicated the same, with an increase in granulation tissue suggesting that the topical application moderately improves the wound healing in diabetic rats. We conclude that Botroclot can have a mild to moderate effect in improving collagen deposition and thus wound contraction, improving wound closure in diabetic wounds in rats. This study also establishes the basis for exploration of agents from venom-based sources in diabetic wound healing.

Curcumin Nanoparticles Improved Diabetic Wounds Infected With Methicillin-Resistant Staphylococcus aureus Sensitized With HAMLET

Accurately orchestrated course of events normally observed in healing are not followed in diabetic wounds, and bacterial colonization/infection further messes up the process. Novel therapeutic options for treatment of infections caused by multidrug-resistant Staphylococcus aureus are urgently needed. HAMLET (human α-lactalbumin made lethal to tumor cells) has been reported to be able to sensitize bacterial pathogens to traditional antimicrobial agents. The aim was to assess the wound healing activity of curcumin nanoparticles in diabetic wounds infected with methicillin-resistant Staphylococcus aureus (MRSA) sensitized with HAMLET. Fifty male rats were randomized into 5 groups of 10 animals each. In CONTROL group, 0.1-mL sterile saline 0.9% solution was added to the wounds with no infection. In MRSA group, the wounds were infected with MRSA and only treated with 0.1-mL sterile saline 0.9% solution. In MRSA/HAMLET group, infected wounds were treated with HAMLET (100 µg). In MRSA/CNP group, animals with infected wounds were treated with 0.1 mL topical application of 1 mg/mL curcumin nanoparticles. In MRSA/CNP/HAMLET group, animals with infected wounds were treated with topical application of 0.1 mL solution of curcumin nanoparticles (1 mg/mL) and HAMLET (100 µg). All test formulations were applied for 10 days, twice a day, starting from first treatment. Microbiological examination; planimetric, biochemical, histological, and quantitative morphometric studies; immunohistochemical staining for angiogenesis; determination of hydroxyproline levels; and reverse transcription polymerase chain reaction for caspase 3, Bcl-2, and p53 showed that there was significant difference between animals in MRSA/CNP/HAMLET group compared with other groups (P < .05). Curcumin nanoparticles improved diabetic wounds infected with MRSA sensitized with HAMLET and had the potential to offer more attention to this safer agent for topical use in infected diabetic wounds.

Polyethylene Glycol–Based Nanocerium Improves Healing Responses in Excisional and Incisional Wound Models in Rats

Applications of nanotechnology have gained progressive interest for regeneration of injured wound tissue. The aim of the present study was to evaluate effects of polyethylene glycol (PEG)-based nanocerium on excisional and incisional wound models in rats. For excisional wound healing model, 24 male white Wistar rats were randomized into 4 groups of 6 rats each: control group with creation of wounds and no treatment, PEG group with creation of wounds and dressing the wound with PEG, NanoCer group with application of 1 mL nanocerium on the wound, and PEG/NanoCer group with dressing the wound with PEG-based nanocerium. Wound size was measured on days 6, 9, 12, 15, 18, and 21 postsurgery. For incisional wound healing model, 24 healthy male Wistar rats were randomized into 4 groups of 6 rats each the same way in the excisional wound model. Reduction in wound area, hydroxyproline contents, and biomechanical parameters indicated that there was a significant difference ( P > .05) between PEG/NanoCer and other groups. Biomechanical testing was performed on day 9 postsurgery in the incisional model. Biochemical and quantitative histological studies demonstrated that there was a significant difference ( P > .05) between PEG/NanoCer and other groups. PEG/NanoCer offered potential advantages in wound healing acceleration and improvement through angiogenesis stimulation, fibroblast proliferation, and granulation tissue formation on early days of healing phases. Acceleration in wound repair was associated with earlier wound area reduction and enhanced tensile strength of damaged area by rearrangement of granulation tissue and collagen fibers. PEG-based nanocerium could have therapeutic benefits in wound healing.

Effects of Chitosan/Nano Selenium Biofilm on Infected Wound Healing in Rats; An Experimental Study

Objective

The present study was aimed at assessment of effect of application of Chitosan/Nano Selenium biofilm on infected wound healing in rats.

Methods

Sixty-eight male Wistar rats were randomized into four groups of 17 animals each. In group I (Normal) the wounds were created with no infection. In group II (MRSA), the wounds were infected with methicillin resistant Staphylococcus aureus (MRSA). In group III (MRSA/CHIT), animals with infected wounds were dressed with chitosan biofilm only. In group IV (MRSA/CHIT/NS), animals with infected wounds were dressed with Chitosan/Nano Selenium biofilm.

Results

There were significant differences in comparisons of group IV and other groups, particularly in terms of cellular infiltration and neovascularization. During the study period, scores for neovascularization was significantly higher in group IV rats than other groups (P<0.05). Polymorphonuclear (PMN) and mononuclear (MNC) cell count and fibroblast cell proliferation in group IV were significantly higher than those of other experimental groups (P<0.05).

Conclusion

Chitosan/Nano Selenium biofilm resulted in significant improvement in histopathological indices in full thickness infected wound healing.

Role of Topical Biological Therapies and Dressings in Healing Ischemic Wounds

Ischemic wounds are the most severe expression of critical limb ischemia (CLI), and they have been defined clinically as an end stage of peripheral arterial disease. Urgent revascularization is a fundamental part for limb salvage in patients with CLI. However, the risk of revascularization should be weighed against the likelihood of success given a patient’s life-threatening comorbidities. Once the condition of arterial insufficiency is revascularized, wound care is an important aspect to promote the wound healing process and infection control. MOIST concept for wound care is a modern systematic treatment for enhanced wound healing process. Currently, advanced biological therapies are emerging in ischemic wound therapies to restore the wound healing process and involve active biological agents to support the wound healing process. We studied and summarized the different types of available topical biological therapies and their mechanisms on the healing process including platelet-derived growth factor, epidermal growth factor, fibroblast growth factor, and vascular endothelial growth factor, platelet-rich plasma, and honey for local wound care of patient with CLI. Our review suggests that topical platelet-derived growth factor, epidermal growth factor, platelet-rich plasma, and honey are available as well as considered in the ischemic wound healing process enhancement through the MOIST concept. In conclusion, biologic wound dressing or topical agent therapy may improve the wound healing process, increase limb salvage, is inexpensive, and provides potential safety with nontoxic low-risk therapy in patients with an ischemic wound. Thus, local wound care by biological dressing should be added in adjuvant treatment for ischemic wound patients. However, further randomized studies are needed to support efficacy and long-term outcomes of these biological dressing in patients with ischemic wound.

Evaluation of antibiotic activity of methicillin in healing of full-thickness infected wounds with sensitized methicillin resistant Staphylococcus aureus in the presence of HAMLET

OBJECTIVES

The novel healing choices for handling of infections due to multidrug resistant Staphylococcus aureus are reguired. HAMLET has been reported to be able to sensitize bacterial pathogens to traditional antimicrobial agents. The aim was to assess wound healing activity of methicillin in presence of HAMLET in methicillin resistant S. aureus (MRSA) infected wounds.

MATERIALS AND METHODS

Fifty male rats were randomized into five groups of ten animals each. In CONTROL group, 0.1 ml sterile saline 0.9% solution was added to the wounds with no infection. In MRSA group, the wounds were infected with MRSA and only treated with 0.1 ml the sterile saline (0.9%) solution. In MRSA/HAMLET group, infected wounds were cured with HAMLET (100 µg). In group MRSA/ Met, animals with infected wounds were cured with 0.1 ml local use of 1 mg/ml methicillin. In MRSA/Met/HAMLET group, animals with infected wounds were cured with local use of 0.1 ml solution of methicillin (1 mg/ml) and HAMLET (100 µg). All test formulations were used for ten consecutive days, twice a day, beginning from first treatment.

RESULTS

Microbiological examination, planimetric, histological and quantitative morphometric studies, immunohistochemical staining for angiogenesis, determination of hydroxyproline levels and RT-PCR for Caspase 3, Bcl-2 and p53 showed that there was significant difference between animals in MRSA/Met/ HAMLET group compared to other groups (P<0.05).

CONCLUSION

HAMLET could make methicillin beneficial for handling of MRSA infected wounds and had the prospective effect to consider this harmless agent for local application.

A new nanoscale transdermal drug delivery system: oil body-linked oleosin-hEGF improves skin regeneration to accelerate wound healing

Background

Epidermal growth factor (EGF) can promote cell proliferation as well as migration, which is feasible in tissue wound healing. Oil bodies have been exploited as an important platform to produce exogenous proteins. The exogenous proteins were expressed in oil bodies from plant seeds. The process can reduce purification steps, thereby significantly reducing the purification cost. Mostly, the diameter of oil body particle ranges between 1.0 and 1.5 µm in the safflower seeds, however, it reduces to 700–1000 nm in the transgenic safflower seeds. The significant reduction of particle size in transgenic seeds is extremely beneficial to skin absorption.

Results

The diameter of oil body in the transgenic safflower seeds was recorded in the range of 700–1000 nm. The smaller particle size improved their skin absorption. The expression level of oleosin-hEGF-hEGF in T3 transgenic seeds was highest at 69.32 mg/g of seeds. The oil body expressing oleosin-hEGF-hEGF had significant proliferative activity on NIH/3T3 cells and improved skin regeneration thereby accelerating wound healing in rats. The wound coverage rate exceeded 98% after treatment for 14 days with oil body expressing oleosin-hEGF-hEGF, while the saline without EGF group and wild type oil body group both showed less than 80%. The neonatal fibroblast and collagen were found to be increased in the safflower oil body expressing oleosin-hEGF-hEGF treatment group. TGF-β1, bFGF and VEGF were noted as important growth factors in the repair of cutaneous wounds. Their expression level increased after 4 and 7 day treatment, but decreased after 14 days. Therefore, it can promote skin regeneration to accelerate wounds healing.

Conclusions

The expression of oleosin-hEGF-hEGF in T3 transgenic seeds was 80.43 ng/μL oil body. It had significant proliferative activity on NIH/3T3 cells and improved skin regeneration to accelerate wound healing in rats. The expression process of TGF-β1, bFGF and VEGF increased at first and then gradually declined.

Electronic supplementary material

The online version of this article (10.1186/s12951-018-0387-5) contains supplementary material, which is available to authorized users.

Planimetric and Biomechanical Study of Local Effect of Pulegone on Full Thickness Wound Healing in Rat

Background

Pulegone as principal component of essential oil, reported to have anti-bacterial, antioxidant and anti-inflammatory properties. The present study was aimed to evaluate wound healing activity of pulegone in a rat model.

Method

Forty rats were used for excisional and incisional wound healing models. For each model twenty male white Wistar rats were randomly divided into five groups (n = 4) of control (CG), Sham surgery, E1, E2 and E3. Wound size, hydroxyproline content of wound and biomechanical testing were assessed.

Result

In E2 animals, the wound size was reduced earlier than in E1 and E2 groups (P = 0.035). However, time had significant effect on wound contraction of all wounds. Hydroxyproline contents in the groups CG, sham surgery, E1, E2 and E3 were found to be 51.25 ± 3.40, 58.41 ± 4.62, 68.59 ± 3.53, 86.32 ± 3.18, and 74.26 ± 4.73 mg g^-1, respectively. Hydroxyproline contents were increased significantly in E2 compared to E1 and E3 which implied more collagen deposition compared to other experimental groups (P = 0.001). The biomechanical indices, maximum stored energy, stiffness, ultimate strength and yield strength obtained for E2 group were significantly higher than those obtained for E1 and E2 groups (P = 0.002).

Conclusion

The pulegone showed a reproducible wound healing potential in rats.

Effects of structurally stabilized EGF and bFGF on wound healing in type I and type II diabetic mice

Diabetes mellitus comprises a multiple metabolic disorder that affects millions of people worldwide and consequentially poses challenges for clinical treatment. Among the various complications, diabetic ulcer constitutes the most prevalent associated disorder and leads to delayed wound healing. To enhance wound healing capacity, we developed structurally stabilized epidermal growth factor (ST-EGF) and basic fibroblast growth factor (ST-bFGF) to overcome limitations of commercially available EGF (CA-EGF) and bFGF (CA-bFGF), such as short half-life and loss of activity after loading onto a matrix. Neither ST-EGF nor ST-bFGF was toxic, and both were more stable at higher temperatures than CA-EGF and CA-bFGF. We loaded ST-EGF and ST-bFGF onto a hyaluronate-collagen dressing (HCD) matrix, a biocompatible carrier, and tested the effectiveness of this system in promoting wound healing in a mouse model of diabetes. Wounds treated with HCD matrix loaded with 0.3 μg/cm² ST-EGF or 1 μg/cm² ST-bFGF showed a more rapid rate of tissue repair as compared to the control in type I and II diabetes models. Our results indicate that an HDC matrix loaded with 0.3 μg/cm² ST-EGF or 1 μg/cm² ST-bFGF can promote wound healing in diabetic ulcers and are suitable for use in wound dressings owing to their stability for long periods at room temperature.

STATEMENT OF SIGNIFICANCE

Various types of dressing materials loaded with growth factors, such as VEGF, EGF, and bFGF, are widely used to effect wound repair. However, such growth factor-loaded materials have several limitations for use as therapeutic agents in healing-impaired diabetic wounds. To overcome these limitations, we have developed new materials containing structurally stabilized EGF (ST-EGF) and bFGF (ST-bFGF). To confirm the wound healing capacity of newly developed materials (ST-EGF and ST-bFGF-loaded hyaluronate-collagen dressing [HCD] matrix), we applied these matrices in type I and type II diabetic wounds. Notably, these matrices were able to accelerate wound healing including re-epithelialization, neovascularization, and collagen deposition. Consequentially, these ST-EGF and ST-bFGF-loaded HCD matrix may be used as future therapeutic agents in patients with diabetic foot ulcers.

Effects of Aloe Vera and Chitosan Nanoparticle Thin-Film Membranes on Wound Healing in Full Thickness Infected Wounds with Methicillin Resistant Staphylococcus Aureus

Objective

To assess effect of Aleo vera with chitosan nanoparticle biofilm on wound healing in full thickness infected wounds with antibiotic resistant gram positive bacteria.

Method

Thirty rats were randomized into five groups of six rats each. Group I: Animals with uninfected wounds treated with 0.9% saline solution. Group II: Animals with infected wounds treated with saline. Group III: Animals with infected wounds were dressed with chitosan nanoparticle thin-film membranes. Group IV: Animals with infected wounds were treated topically with Aloe vera and Group V: Animals with infected wounds were treated topically with Aloe vera and dressed with chitosan nanoparticle thin-film membranes. Wound size was measured on 6, 9, 12, 15, 18 and 21days after surgery.

Results

Microbiology, reduction in wound area and hydroxyproline contents indicated that there was significant difference (p<0.05) between group V and other groups. Quantitative histological studies and mean rank of the qualitative studies demonstrated that there was significant difference (p<0.05) between group V and other groups.

Conclusion

The Aloe vera with chitosan nanoparticle thin-film membranes had a reproducible wound healing potential and hereby justified its use in practice.

The Extract of Lycium depressum Stocks Enhances Wound Healing in Streptozotocin-Induced Diabetic Rats

In diabetes, impaired wound healing and other tissue abnormalities are considered major concerns. The aim of the present study was to assess the wound-healing activity of methanolic extracts of the extract of Lycium depressum leaves. A total of 60 healthy male Wistar diabetic rats weighing approximately 160 to 180 g and 7 weeks of age were randomized into 10 groups for incision and excision wound models: sham surgery group (SHAM), including creation of wounds and no treatment; base formulation group (FG) with creation of wounds and application of base formulation ointment; treatment group 1 (TG1) with 1 g of powder extract of the plant material in ointment; treatment group 2 (TG2) with 2 g; and treatment group 4 (TG3) with 4 g of powder extract of the plant material in ointment. A wound was induced by an excision- and incision-based wound model in male rats. The mature green leaves of L depressum were collected and authenticated. Extractions of dried leaves were carried out. For wound-healing activity, the extracts were applied topically in the form of ointment and compared with control groups. The healing of the wound was assessed based on excision, incision, hydroxyproline estimation, and biomechanical and biochemical studies. The extract of L depressum leaves enhanced wound contraction, decreased epithelialization time, increased hydroxyproline content, and improved mechanical indices and histological characteristics in treatment groups compared with SHAM and FG ( P < .05). These findings permit the conclusion the extract of L depressum benefits parameters of wound healing in a diabetes induced model.

Development of Stabilized Growth Factor-Loaded Hyaluronate- Collagen Dressing (HCD) matrix for impaired wound healing

BACKGROUND

Diabetes mellitus is a disease lack of insulin, which has severely delayed and impaired wound healing capacity. In the previous studies, various types of scaffolds and growth factors were used in impaired wound healing. However, there were several limitations to use them such as short half-life of growth factors in vivo and inadequate experimental conditions of wound-dressing material. Thus, our study aimed to determine the biocompatibility and stability of the matrix containing structurally stabilized epidermal growth factor (S-EGF) and basic fibroblast growth factor (S-bFGF).

RESULTS AND DISCUSSION

We stabilized EGF and bFGF that are structurally more stable than existing EGF and bFGF. We developed biocompatible matrix using S-EGF, S-bFGF, and hyaluronate- collagen dressing (HCD) matrix. The developed matrix, S-EGF and S-bFGF loaded on HCD matrix, had no cytotoxicity, in vitro. Also, these matrixes had longer releasing period that result in enhancement of half-life. Finally, when these matrixes were applied on the wound of diabetic mice, there were no inflammatory responses, in vivo. Thus, our results demonstrate that these matrixes are biologically safe and biocompatible as wound-dressing material.

CONCLUSIONS

Our stabilized EGF and bFGF was more stable than existing EGF and bFGF and the HCD matrix had the capacity to efficiently deliver growth factors. Thus, the S-EGF and S-bFGF loaded on HCD matrix had improved stability. Therefore, these matrixes may be suitable for impaired wound healing, resulting in application of clinical treatment.

Chemokines as Therapeutic Targets to Improve Healing Efficiency of Chronic Wounds

Significance: Impaired wound healing leading to chronic wounds is an important clinical problem that needs immediate attention to develop new effective therapies. Members of the chemokine family seem to be attractive and amenable to stimulate the healing process in chronic wounds. Targeting specific chemokines and/or their receptors has the potential to modify chronic inflammation to acute inflammation, which will hasten the healing process. Recent Advances: Over the years, expression levels of various chemokines and their receptors have been identified as key players in the inflammatory phase of wound healing. In addition, they contribute to regulating other phases of wound healing making them key targets for novel therapies. Understanding the signaling pathways of these chemokines will provide valuable clues for modulating their function to enhance the wound healing process. Critical Issues: Inflammation, an important first-stage process in wound healing, is dysregulated in chronic wounds; emerging studies show that chemokines play a crucial role in regulating inflammation. The knowledge gained so far is still limited in understanding the enormous complexity of the chemokine network during inflammation not just in chronic wounds but also in acute (normal) wounds. A much better understanding of the individual chemokines will pave the way for better targets and therapies to improve the healing efficiency of chronic wounds. Future Directions: Effective understanding of the interaction of chemokines and their receptors during chronic wound healing would facilitate the design of novel therapeutic drugs. Development of chemokine-based drugs targeting specific inflammatory cells will be invaluable in the treatment of chronic wounds, in which inflammation plays a major role.

A new mouse model for wound healing in hemophilia A

PURPOSE

To establish a new mouse model for wound healing studies on hemophilia A.

METHODS

Total 54 male mice with different genotypes including wild-type nude mice, heterozygous mice (FVIII-/-/Nu) and FVIII deficient mice (FVIII-/-) were generated and verified by PCR. Mice were subjected to wound healing research by making a 5 mm-thickness wound on mice skin and applying recombinant human epidermal growth factor (EGF, 10 μg/g) ointment, FVIII ointment (30 IU) or the ointment base to heal the wounds. Furthermore, keratinocytes were isolated from these newborn mice and subjected to migration assay by stimulation of EGF (ng/ml), insulin (10 μM) or vehicle.

RESULTS

A new hemophilic mouse model (FVIII-/-/Nu) was constructed successfully after genotyping verified by PCR. Compared to FVIII-/- mice, FVIII-/-/Nu and Nu mice showed greater degree of wound contraction and loss of the crust. Topical treatment with EGF exhibited faster wound healing than FVIII and ointment base. Insulin treatment showed more increased migration distance than treated with EGF or vehicle. FVIII-/-/Nu mice showed greater migration than FVIII-/- and Nu mice.

CONCLUSIONS

A new mouse model (FVIII-/-/Nu) for wound healing in hemophilia A was constructed, and topical treatment of insulin may be a better therapy than EGF for healing wounds in hemophilia A.

Comparison of salivary epidermal growth factor levels in patients with gingivitis and advanced periodontitis and healthy subjects

OBJECTIVE

Epidermal growth factor (EGF) is a polypeptide molecule, with important functions in epithelial growth and wound repair. It exerts its effects on cells by binding to receptors on the cell surface. The aim of this study was to evaluate and compare salivary EGF levels in patients with gingivitis and advanced periodontitis as well as in healthy controls.

MATERIAL AND METHODS

Unstimulated salivary samples were collected from patients with gingivitis and advanced periodontitis and healthy individuals. The clinical parameters of plaque index (PI), bleeding on probing (BOP), probing pocket depth (PPD) and clinical attachment level (CAL) were measured and recorded using a Williams probe. The enzyme-linked immunosorbent assay (ELISA) was used to determine salivary levels of EGF. One-way ANOVA was used for data analysis.

RESULTS

The mean salivary level of EGF in healthy individuals (99.27) was significantly higher than that in patients with gingivitis (61.53). This value in patients with gingivitis (61.53) was also significantly higher than that in subjects with periodontitis (36.14) (P<0.001).

CONCLUSION

The reduction in salivary level of EGF in patients with periodontal disease may be related to the pathogenesis of periodontitis.

Epidermal Growth Factor and Epidermal Growth Factor Receptor: The Yin and Yang in the Treatment of Cutaneous Wounds and Cancer

SIGNIFICANCE

Epidermal growth factor (EGF) and EGF receptor (EGFR) play an essential role in wound healing through stimulating epidermal and dermal regeneration. The development of new therapies for enhancing wound healing has included the use of EGF. In addition, EGFR inhibitors (EGFRis) have become a therapeutic option for the treatment of cancer. Thus, therapies targeting EGF/EGFR are useful for the treatment of both cutaneous wounds and cancer.

RECENT ADVANCES

Identification of EGFR as a regulator of normal and pathological cell function has allowed for the development of EGFRis for the treatment of cancer and topical administration of EGF to enhance wound healing.

CRITICAL ISSUES

The use of EGFRi has emerged as an option for metastatic cancers. These drugs induce dermatological toxicity, a papulopustular rash that is pruritic and painful; chronic use may negatively impact wound healing. Currently, there is no standard therapy to alleviate the side effects caused by EGFRi administration except to reduce or eliminate EGFRi usage. Therefore, side effects from these drugs should be taken into consideration on patients prone to develop chronic wounds and with cutaneous injuries.

FUTURE DIRECTIONS

There is a need for adjunctive treatment to eliminate dermatological toxicity from EGFRi use. The development of new downstream targets of EGFR may be a rational strategy to reduce potential cutaneous side effects and provide a better strategy for the treatment of cancer. Until then, the topical use of EGF could be used to ameliorate dermatological lesions caused by EGFRi.

Mobilised bone marrow-derived cells accelerate wound healing

Massive skin defects caused by severe burn and trauma are a clinical challenge to surgeons. Timely and effective wound closure is often hindered by the lack of skin donor site. Bone marrow-derived cells (BMDCs) have been shown to 'differentiate' into multiple tissue cells. In this study we focused on the direct manipulation of endogenous BMDCs, avoiding the immunocompatibility issues and complicated cell isolation, purification, identification and amplification procedures in vitro on wound repair. We found that mobilisation of the BMDCs into the circulation significantly increased the amount of BMDCs at the injury site which in turn accelerated healing of large open wound. We used a chimeric green fluorescent protein (GFP) mouse model to track BMDCs and to investigate their role in full-thickness skin excisional wounds. We have shown that bone marrow mobilisation by granulocyte colony stimulating factor (G-CSF) exerted multiple beneficial effects on skin repair, both by increasing the engraftment of BMDCs into the skin to differentiate into multiple skin cell types and by upregulating essential cytokine mRNAs critical to wound repair. The potential trophic effects of G-CSF on bone marrow stem cells to accelerate wound healing could have a significant clinical impact.

Topical embryonic stem cells enhance wound healing in diabetic rats

The effects of embryonic stem cells (ESCs) on diabetic wound healing were investigated using an excisional skin wound model in 110 diabetes-induced rats. We transplanted a clonal population of ESCs (5 × 10(6)) by topical injection into full thickness skin wounds. Four study groups were used; nondiabetic rats as a control, non-insulin controlled diabetic rats not treated with ESCs, insulin controlled diabetic rats not treated with ESCs, and insulin controlled diabetic rats treated with ESCs. Five rats in each experimental group were sacrificed on days 1, 5, 10, 15, and 20 after wounding. Wounds images were acquired daily and wound sizes were calculated. We measured the mRNA levels of epidermal growth factor (EGF) and vascular endothelial growth factor (VEGF), and fibronectin levels in extracellular matrix, and assessed wound healing by assessing histological parameters of epidermal regeneration, granulation tissue thickness, and angiogenesis. In the ESC-treated group, wound sizes were significantly smaller than in the insulin controlled diabetic group not treated with ESCs on days 5 and 10 (p < 0.05), and EGF and VEGF levels were markedly higher on days 5 and 10, fibronectin levels on day 5 after injection. All histological scores in the ESC-treated group were significantly higher than those of the insulin controlled diabetic group on day 5 (p < 0.05). Our results shows that topical ESCs enhance diabetic wound healing during the early stage, and suggest that ESCs transplantation offers a novel therapeutic modality for the treatment of diabetic wounds.

Surface and Cell Affinity Properties of Chitosan-Gelatin-Hydroxyapatite Composite Films

Addition of hydroxyapatite (HAp) into polymeric matrices and use them as supporting material for tissue engineering has gained attraction since hydroxyapatite (HAp) type crystals are the main inorganic components of the bone structure. In this study, composite films were prepared from chitosan (C) and gelatin (G) with addition of HAp, and the surface characterization and cell affinity properties were examined. The hydrophilicities and morphologies of the films were investigated by contact angle measurements and by scanning electron microscopy (SEM), respectively. Cell affinities were studied by using human osteosarcoma (SaOs-2) cell line. Crosslinked and HAp containing films were found to be more hydrophilic than that of the others, while surface free energy (SFE) values were almost similar for all films. Cell proliferation and spreading of SaOs-2 cells were higher for the films with high gelatin content and no HAp; whereas for HAp containing composites higher cell affinities were obtained for the samples which have high chitosan content.

Quantitative automated microscopy (QuAM) elucidates growth factor specific signalling in pain sensitization

Background

Dorsal root ganglia (DRG)-neurons are commonly characterized immunocytochemically. Cells are mostly grouped by the experimenter's eye as "marker-positive" and "marker-negative" according to their immunofluorescence intensity. Classification criteria remain largely undefined. Overcoming this shortfall, we established a quantitative automated microscopy (QuAM) for a defined and multiparametric analysis of adherent heterogeneous primary neurons on a single cell base.

The growth factors NGF, GDNF and EGF activate the MAP-kinase Erk1/2 via receptor tyrosine kinase signalling. NGF and GDNF are established factors in regeneration and sensitization of nociceptive neurons. If also the tissue regenerating growth factor, EGF, influences nociceptors is so far unknown. We asked, if EGF can act on nociceptors, and if QuAM can elucidate differences between NGF, GDNF and EGF induced Erk1/2 activation kinetics. Finally, we evaluated, if the investigation of one signalling component allows prediction of the behavioral response to a reagent not tested on nociceptors such as EGF.

Results

We established a software-based neuron identification, described quantitatively DRG-neuron heterogeneity and correlated measured sample sizes and corresponding assay sensitivity. Analysing more than 70,000 individual neurons we defined neuronal subgroups based on differential Erk1/2 activation status in sensory neurons. Baseline activity levels varied strongly already in untreated neurons. NGF and GDNF subgroup responsiveness correlated with their subgroup specificity on IB4(+)- and IB4(-)-neurons, respectively. We confirmed expression of EGF-receptors in all sensory neurons. EGF treatment induced STAT3 translocation into the nucleus. Nevertheless, we could not detect any EGF induced Erk1/2 phosphorylation. Accordingly, intradermal injection of EGF resulted in a fundamentally different outcome than NGF/GDNF. EGF did not induce mechanical hyperalgesia, but blocked PGE₂-induced sensitization.

Conclusions

QuAM is a suitable if not necessary tool to analyze activation of endogenous signalling in heterogeneous cultures. NGF, GDNF and EGF stimulation of DRG-neurons shows differential Erk1/2 activation responses and a corresponding differential behavioral phenotype. Thus, in addition to expression-markers also signalling-activity can be taken for functional subgroup differentiation and as predictor of behavioral outcome. The anti-nociceptive function of EGF is an intriguing result in the context of tissue damage but also for understanding pain resulting from EGF-receptor block during cancer therapy.