The role of growth factors in wound healing

M2 Macrophage Polarization and Tissue Remodeling in Autologous Fat Grafting for Diabetic Skin Defects

Autologous adipose tissue was recognized as a promising therapeutic option for soft tissue defects owing to its regenerative potential and ability to facilitate tissue reconstruction. However, the mechanisms by which autologous fat grafting (AFG) promotes healing remain unclear, hindering its potential applications. This study aimed to investigate the distribution and phenotypic transition of infiltrating macrophages in transplanted adipose tissue, as well as their correlation with diabetic skin defect remodeling. Streptozotocin-induced diabetic rats with full-thickness dorsal skin defects were included in this study. The transplanted adipose tissue at the skin defects was collected and analyzed using flow cytometry to determine macrophage proportion and phenotype. The healing of skin defects was evaluated, and treatment was continued until day 14 as the designated endpoint of healing, followed by histopathologic examinations. Immunostaining with CD31 and lymphatic vessel endothelial receptor-1 was performed on wound tissues to analyze angiogenesis and lymphangiogenesis, respectively. Western blot and quantitative polymerase chain reaction analyses were used to assess the expression of the representative genes involved in the healing process. The results showed early polarization of M2 macrophages in the transplanted adipose tissue, concomitant with the upregulation of growth factors and downregulation of inflammatory factors. In vivo experiments revealed that AFG significantly promoted macrophage infiltration and M2 transformation in diabetic skin defects compared to the control groups, thereby promoting tissue extracellular matrix remodeling and lymphatic and vascular regeneration. However, the beneficial effects of AFG were inhibited by macrophage depletion. This study further demonstrated the potential of AFG for treating diabetic skin defects.

Anti-inflammatory and tissue repair effect of cinnamaldehyde and nano cinnamaldehyde on gingival fibroblasts and macrophages

BACKGROUND

Recurrent aphthous stomatitis has a complex and inflammatory origin. Among the great variety of medications it is increasingly common to use herbal medicines due to the adverse side effects of chemical medications. Considering the anti-inflammatory properties of cinnamaldehyde and the lack of studies related to the effectiveness of its nano form; This study investigates the effect of cinnamaldehyde and nano cinnamaldehyde on the healing rate of recurrent aphthous stomatitis lesions.

METHODS

In a laboratory experiment, cinnamaldehyde was converted into niosomal nanoparticles. The niosome vesicles diameter and polydispersity index were measured at 25°C using a dynamic light scattering (DLS) Mastersizer 2000 (Malvern Panalytical technologies: UK) and Zetasizer Nano ZS system (Malvern Instruments Worcestershire: UK). After characterizing these particles, the (2,3-Bis-(2-Methoxy-4-Nitro-5-Sulfophenyl)-2H-Tetrazolium-5-Carboxanilide) [XTT] assay was used to assess the toxicity of cinnamaldehyde and nano cinnamaldehyde on gingival fibroblast (HGF) and macrophage (THP-1) cells. By determining the release of TNF-α, IL-6, and TGF-β cytokines using ELISA kits, the level of tissue repair and anti-inflammatory capabilities of these two substances were evaluated.

RESULTS

The size and loading rate of the cinnamaldehyde nanoparticles were established after its creation. The optimized nanovesicle exhibited the following characteristics: particle size of 228.75 ± 2.38 nm, PDI of 0.244 ± 0.01, the zeta potential of -10.87 ± 1.09 mV and the drug encapsulation percentage of 66.72 ± 3.93%. PDIs range was between 0.242-0.274. The zeta potential values at 25°C were from -2.67 to -12.9 mV. The results of the XTT test demonstrated that nano cinnamaldehyde exhibited dose-dependent toxicity effects. Moreover, nano cinnamaldehyde released more TGF-β and had better reparative effects when taken at lower concentrations than cinnamaldehyde.

CONCLUSION

Nano cinnamaldehyde and cinnamaldehyde are effective in repairing tissue when used in non-toxic amounts. After confirmation in animal models, it is envisaged that these substances can be utilized to treat recurrent aphthous stomatitis.

Development of Thiol-Ene Reaction-Based HA Hydrogel with Sustained Release of EGF for Enhanced Skin Wound Healing

This study develops a novel drug delivery system using a hyaluronic acid (HA) hydrogel for controlled release of epidermal growth factor (EGF) to enhance skin wound healing. Conventional hydrogel-based methods suffer from a burst release and limited drug delivery times. To address this, we employ bioconjugation to introduce an acrylate group to EGF, enabling chemical bonding to the HA hydrogel matrix through thiol-ene cross-linking. This approach results in sustained-release delivery of EGF based on the degradation rate of the HA matrix, overcoming diffusion-based limitations. We confirm the introduction of the acrylate group using matrix-assisted laser desorption ionization-time-of-flight (MALDI-TOF) mass spectrometry. We evaluated the hydrogel morphology and rheological properties following binding of acrylate-conjugated EGF to the HA matrix. Assessment of the EGF release profile demonstrates delayed release compared to unconjugated EGF. We evaluate the impact on cells through cell proliferation and scratch assays, indicating the system's efficacy. In a rat wound healing model, the sustained release of EGF from the hydrogel system promotes appropriate tissue healing and restores it to a normal state. These findings suggest that this practical drug delivery system, involving the modification of growth factors or drugs to chemically bind healing factors to hydrogels, can achieve long-lasting effects.

Burn Wound Bed Management

Critical to the success of modern burn care is the management of the burn wound. Timely and complete removal of nonviable tissue is complicated by the irreplaceable nature of the tissue lost either through the burn injury or as "collateral damage" as part of the treatment. Challenges in distinguishing between viable and nonviable tissue and "replacing the irreplaceable" are discussed alongside potential disruptive technologies which could fundamentally change how burn care is delivered. Advances in burn wound bed management forms the foundation on which the goal of zero preventable death and disability after burn injury can be achieved.

Advances in Skin Tissue Engineering and Regenerative Medicine

There are an estimated 500,000 patients treated with full-thickness wounds in the United States every year. Fire-related burn injuries are among the most common and devastating types of wounds that require advanced clinical treatment. Autologous split-thickness skin grafting is the clinical gold standard for the treatment of large burn wounds. However, skin grafting has several limitations, particularly in large burn wounds, where there may be a limited area of non-wounded skin to use for grafting. Non-cellular dermal substitutes have been developed but have their own challenges; they are expensive to produce, may require immunosuppression depending on design and allogenic cell inclusion. There is a need for more advanced treatments for devastating burns and wounds. This manuscript provides a brief overview of some recent advances in wound care, including the use of advanced biomaterials, cell-based therapies for wound healing, biological skin substitutes, biological scaffolds, spray on skin and skin bioprinting. Finally, we provide insight into the future of wound care and technological areas that need to be addressed to support the development and incorporation of these technologies.

The effects of mechanical force on fibroblast behavior in cutaneous injury

Wound healing results in the formation of scar tissue which can be associated with functional impairment, psychological stress, and significant socioeconomic cost which exceeds 20 billion dollars annually in the United States alone. Pathologic scarring is often associated with exaggerated action of fibroblasts and subsequent excessive accumulation of extracellular matrix proteins which results in fibrotic thickening of the dermis. In skin wounds, fibroblasts transition to myofibroblasts which contract the wound and contribute to remodeling of the extracellular matrix. Mechanical stress on wounds has long been clinically observed to result in increased pathologic scar formation, and studies over the past decade have begun to uncover the cellular mechanisms that underly this phenomenon. In this article, we will review the investigations which have identified proteins involved in mechano-sensing, such as focal adhesion kinase, as well as other important pathway components that relay the transcriptional effects of mechanical forces, such as RhoA/ROCK, the hippo pathway, YAP/TAZ, and Piezo1. Additionally, we will discuss findings in animal models which show the inhibition of these pathways to promote wound healing, reduce contracture, mitigate scar formation, and restore normal extracellular matrix architecture. Recent advances in single cell RNA sequencing and spatial transcriptomics and the resulting ability to further characterize mechanoresponsive fibroblast subpopulations and the genes that define them will be summarized. Given the importance of mechanical signaling in scar formation, several clinical treatments focused on reducing tension on the wound have been developed and are described here. Finally, we will look toward future research which may reveal novel cellular pathways and deepen our understanding of the pathogenesis of pathologic scarring. The past decade of scientific inquiry has drawn many lines connecting these cellular mechanisms that may lead to a map for the development of transitional treatments for patients on the path to scarless healing.

Utilization of a topical autologous blood clot for treatment of pressure ulcers

Management and treatment of pressure ulcers (PUs) are met with great difficulty due to various factors that cause vulnerability of the soft tissue such as location, limited mobility, increased friction and shearing forces, as well as other comorbidities that may delay or halt wound healing. The topical autologous blood clot therapy (TABCT) is a point-of-care treatment used as a blood clot to assist in recreating and repairing the extracellular matrix (ECM). The mechanism of action consists of reconstruction of the ECM by incorporating into the ulcer, providing protection from further external destruction, while assisting in advancement through the wound healing phases via interaction of necessary growth factors, mediators, and chemokines. This study aims to assess the efficacy of the TABCT in the treatment of PUs in comparison to standard of care (SOC) treatment. Twenty-four patients, 18 years or older, with PUs ranging from stage 1 to 4, were included in this study. TABCT was created by using the patient's own peripheral blood in a point of care setting. Efficacy in percent area reduction (PAR) on weeks 4 and 12 with TABCT over SOC was assessed. Treatment using TABCT in PUs resulted in 77.9% of the patients achieving a 50% PAR on week 4. The mean PAR on week 12 was 96.23% with 45% of the wounds treated with TABCT achieving complete wound closure. TABCT exhibited efficacy in PAR of PUs. In addition, TABCT use prompted granulation tissue formation over vital structures, such as bone, which is often present in later stage PUs. The potential of bringing an affordable, cost-effective, advanced biologic bedside treatment that is efficacious in resolution of these complex wounds has the potential to drastically reduce the burden of treatment on the health system.

Engineered Nanotechnology: An Effective Therapeutic Platform for the Chronic Cutaneous Wound

The healing of chronic wound infections, especially cutaneous wounds, involves a complex cascade of events demanding mutual interaction between immunity and other natural host processes. Wound infections are caused by the consortia of microbial species that keep on proliferating and produce various types of virulence factors that cause the development of chronic infections. The mono- or polymicrobial nature of surface wound infections is best characterized by its ability to form biofilm that renders antimicrobial resistance to commonly administered drugs due to poor biofilm matrix permeability. With an increasing incidence of chronic wound biofilm infections, there is an urgent need for non-conventional antimicrobial approaches, such as developing nanomaterials that have intrinsic antimicrobial-antibiofilm properties modulating the biochemical or biophysical parameters in the wound microenvironment in order to cause disruption and removal of biofilms, such as designing nanomaterials as efficient drug-delivery vehicles carrying antibiotics, bioactive compounds, growth factor antioxidants or stem cells reaching the infection sites and having a distinct mechanism of action in comparison to antibiotics—functionalized nanoparticles (NPs) for better incursion through the biofilm matrix. NPs are thought to act by modulating the microbial colonization and biofilm formation in wounds due to their differential particle size, shape, surface charge and composition through alterations in bacterial cell membrane composition, as well as their conductivity, loss of respiratory activity, generation of reactive oxygen species (ROS), nitrosation of cysteines of proteins, lipid peroxidation, DNA unwinding and modulation of metabolic pathways. For the treatment of chronic wounds, extensive research is ongoing to explore a variety of nanoplatforms, including metallic and nonmetallic NPs, nanofibers and self-accumulating nanocarriers. As the use of the magnetic nanoparticle (MNP)-entrenched pre-designed hydrogel sheet (MPS) is found to enhance wound healing, the bio-nanocomposites consisting of bacterial cellulose and magnetic nanoparticles (magnetite) are now successfully used for the healing of chronic wounds. With the objective of precise targeting, some kinds of “intelligent” nanoparticles are constructed to react according to the required environment, which are later incorporated in the dressings, so that the wound can be treated with nano-impregnated dressing material in situ. For the effective healing of skin wounds, high-expressing, transiently modified stem cells, controlled by nano 3D architectures, have been developed to encourage angiogenesis and tissue regeneration. In order to overcome the challenge of time and dose constraints during drug administration, the approach of combinatorial nano therapy is adopted, whereby AI will help to exploit the full potential of nanomedicine to treat chronic wounds.

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.

Effect of the Recombinant Human Epidermal Growth Factor Ointment on Cutaneous Surgical Wounds Compared to Antibiotic Ointment

Background

Applying antibiotic ointment after skin surgery can decrease infection and improve scar. Epidermal growth factor (EGF) is known to be able to promote the growth and movement of epidermal cells to stimulate wound healing. Recombinant human EGF (rhEGF) ointment can be used in wet closed dressing to promotes wound healing and prevent complications by maintaining a wet environment.

Objective

To compare the efficacy of rhEGF ointment and conventional antibiotic ointment after cutaneous resection.

Methods

Patients who had excision procedures in two or more sites were enrolled. Each wound was assigned to the rhEGF group or the antibiotic ointment group. Wounds were subjected to Physician Global Assessment (PhGA), Patient Global Assessment (PGA), and Patient satisfaction assessment (PSA). The length and area of wounds, and melanin and erythema index (MI and EI) were also assessed for these wounds.

Results

Among 11 patients with a total of 20 pairs of resection sites, PhGA, PGA, MI, and EI showed no significant difference between rhEGF and antibiotic ointment groups. However, changes in length and area of wounds showed significant differences between the two groups.

Conclusion

RhEGF ointment showed similar short-term cosmetic results with antibiotic ointment, and improved surgical results in regards of the wound size. Applying rhEGF could reduce the use of antibiotic ointments for cutaneous clean (class I) wound surgery.

De novo Drug Delivery Modalities for Treating Damaged Hearts: Current Challenges and Emerging Solutions

Cardiovascular disease (CVD) is the leading cause of mortality, resulting in approximately one-third of deaths worldwide. Among CVD, acute myocardial infarctions (MI) is the leading cause of death. Current treatment modalities for treating CVD have improved over the years, but the demand for new and innovative therapies has been on the rise. The field of nanomedicine and nanotechnology has opened a new paradigm for treating damaged hearts by providing improved drug delivery methods, specifically targeting injured areas of the myocardium. With the advent of innovative biomaterials, newer therapeutics such as growth factors, stem cells, and exosomes have been successfully delivered to the injured myocardial tissue, promoting improvement in cardiac function. This review focuses on three major drug delivery modalities: nanoparticles, microspheres, and hydrogels, and their potential for treating damaged hearts following an MI.

Genetic and Epidemiological Similarities, and Differences Between Postoperative Intraperitoneal Adhesion Development and Other Benign Fibro-proliferative Disorders

Intraperitoneal adhesions complicate over half of abdominal-pelvic surgeries with immediate, short, and long-term sequelae of major healthcare concern. The pathogenesis of adhesion development is similar to the pathogenesis of wound healing in all tissues, which if unchecked result in production of fibrotic conditions. Given the similarities, we explore the published literature to highlight the similarities in the pathogenesis of intra-abdominal adhesion development (IPAD) and other fibrotic diseases such as keloids, endometriosis, uterine fibroids, bronchopulmonary dysplasia, and pulmonary, intraperitoneal, and retroperitoneal fibrosis. Following a literature search using PubMed database for all relevant English language articles up to November 2020, we reviewed relevant articles addressing the genetic and epidemiological similarities and differences in the pathogenesis and pathobiology of fibrotic diseases. We found genetic and epidemiological similarities and differences between the pathobiology of postoperative IPAD and other diseases that involve altered fibroblast-derived cells. We also found several genes and single nucleotide polymorphisms that are up- or downregulated and whose products directly or indirectly increase the propensity for postoperative adhesion development and other fibrotic diseases. An understanding of the similarities in pathophysiology of adhesion development and other fibrotic diseases contributes to a greater understanding of IPAD and these disease processes. At a very fundamental level, blocking changes in the expression or function of genes necessary for the transformation of normal to altered fibroblasts may curtail adhesion formation and other fibrotic disease since this is a prerequisite for their development. Similarly, applying measures to induce apoptosis of altered fibroblast may do the same; however, apoptosis should be at a desired level to simultaneously ameliorate development of fibrotic diseases while allowing for normal healing. Scientists may use such information to develop pharmacologic interventions for those most at risk for developing these fibrotic conditions.

Heparin Microislands in Microporous Annealed Particle Scaffolds for Accelerated Diabetic Wound Healing

Mimicking growth factor-ECM interactions for promoting cell migration is a powerful technique to improve tissue integration with biomaterial scaffolds for the regeneration of damaged tissues. This has been attempted by scaffold-mediated controlled delivery of exogenous growth factors; however, the predetermined nature of this delivery can limit the scaffold's ability to meet each wound's unique spatiotemporal regenerative needs and presents translational hurdles. To address this limitation, we present a new approach to growth factor presentation by incorporating heparin microislands, which are spatially isolated heparin-containing microparticles that can reorganize and protect endogenous local growth factors via heterogeneous sequestration at the microscale in vitro and result in functional improvements in wound healing. More specifically, we incorporated our heparin microislands within microporous annealed particle (MAP) scaffolds, which allows facile tuning of microenvironment heterogeneity through ratiometric mixing of microparticle sub-populations. In this manuscript, we demonstrate the ability of heparin microislands to heterogeneously sequester applied growth factor and control downstream cell migration in vitro. Further, we present their ability to significantly improve wound healing outcomes (epidermal regeneration and re-vascularization) in a diabetic wound model relative to two clinically relevant controls.

Recombinant human epidermal growth factor combined with vacuum sealing drainage for wound healing in Bama pigs

BACKGROUND

Vacuum sealing drainage (VSD) and epidermal growth factor (EGF) both play an important role in the treatment of wounds. This study aims to explore the effects of the combination of VSD and EGF on wound healing and the optimal concentration and time of EGF.

METHODS

We tested the proliferation and migration capacity of HaCaT and L929 cells at different EGF concentrations (0, 1, 5, 10, and 100 ng/ml) and different EGF action times (2, 10, and 30 min). A full-thickness skin defect model was established using male, 30-week-old Bama pigs. The experiment included groups as follows: routine dressing change after covering with sterile auxiliary material (Control), continuous negative pressure drainage of the wound (VSD), continuous negative pressure drainage of the wound and injection of EGF 10 min followed by removal by continuous lavage (V + E 10 min), and continuous negative pressure drainage of the wound and injection of EGF 30 min followed by removal by continuous lavage (V + E 30 min). The wound healing rate, histological repair effect and collagen deposition were compared among the four groups.

RESULTS

An EGF concentration of 10 ng/ml and an action time of 10 min had optimal effects on the proliferation and migration capacities of HaCaT and L929 cells. The drug dispersion effect was better than drug infusion after bolus injection effect, and the contact surface was wider. Compared with other groups, the V + E 10 min group promoted wound healing to the greatest extent and obtained the best histological score.

CONCLUSIONS

A recombinant human epidermal growth factor (rhEGF) concentration of 10 ng/ml can promote the proliferation and migration of epithelial cells and fibroblasts to the greatest extent in vitro. VSD combined with rhEGF kept in place for 10 min and then washed, can promote wound healing better than the other treatments in vivo.

Barrier therapies supporting the biology of the mucosal barrier-medical devices for common clinical mucosal disorders

Recently mucosal barrier therapies have been either CE marked or licensed by Food and Drug Administration (FDA) as medical devices. A barrier therapy (BT) uses a physical non-drug mode of action as its sole mechanism to manage a clinical syndrome. A BT is verified as technically or biologically safe having efficacy that has been proven by valid clinical trials. However, it remains unclear what anatomical portions of the mucosa are physically engaged by any given BT. Therefore, this article clarifies the physical basis for clinical efficacy of any given mucosal BT's. Current regulatory classification of medical devices is defined. More importantly, the biology of mucosal barrier is detailed by structure, compartmental elements and function. A live-function or cross-sectional anatomical perspective of the mucosa is provided. A cross-sectional anatomical perspective of the mucosa is provided in order to highlight the physical point of contact for any given mucosal BT's. Five traits of an effective mucosal BT are proposed to assess traits of fitness for any given BT. A BT is either classical, possessing four to five traits, or non-classical, possessing three or fewer traits. Among 16 commercially available mucosal BT's which share nine distinct formulations, most are non-classical BT while two (alginate and polymeric sucralfate) are classical mucosal BT's.

Potential Applications of Nanomaterials and Technology for Diabetic Wound Healing

Diabetic wound shows delayed and incomplete healing processes, which in turn exposes patients to an environment with a high risk of infection. This article has summarized current developments of nanoparticles/hydrogels and nanotechnology used for promoting the wound healing process in either diabetic animal models or patients with diabetes mellitus. These nanoparticles/hydrogels promote diabetic wound healing by loading bioactive molecules (such as growth factors, genes, proteins/peptides, stem cells/exosomes, etc.) and non-bioactive substances (metal ions, oxygen, nitric oxide, etc.). Among them, smart hydrogels (a very promising method for loading many types of bioactive components) are currently favored by researchers. In addition, nanoparticles/hydrogels can be combined with some technology (including PTT, LBL self-assembly technique and 3D-printing technology) to treat diabetic wound repair. By reviewing the recent literatures, we also proposed new strategies for improving multifunctional treatment of diabetic wounds in the future.

Autologously transplanted dermal fibroblasts improved diabetic wound in rat model

Healing of diabetic wounds are delayed due to late initiation and prolongation of the inflammatory phase, and inadequate growth factor synthesis, which may lead to chronic ulcers that may cause limb amputation, besides making the patients vulnerable to infections. In recent years, it has been extensively discussed whether different cell types transplanted to diabetic wound models accelerate wound healing. In this study, the effect of dermis-derived cells on Streptozotocin (STZ) induced experimental diabetic Sprague-Dawley rats were investigated. Animals were divided into 3 groups. First group was control, second group included diabetic animals with wounds. In the third group, firstly, skin specimens were obtained from animal's back, and then primary explant culture was performed. STZ induced experimental diabetes was applied to these animals and then wound was opened. The cells grown in primary culture were transplanted autologously. In all three groups, the samples taken from the wound areas on the 5th and 15th days of the wound were examined at the level of histochemical and immunohistochemical and electron microscopy. In the study, it was observed that the decreasing α-SMA and KGF (FGF-7) expression in the early period especially in the case of experimental diabetes increased as a result of cell transplantation, and in the sections belonging to the experimental diabetic group, a large number of inflammatory cells in the wound area were removed from the environment. In the cell transplanted group, the collagen fiber bundles as if in the control group. As a result, healthy cells of dermis can act as mesenchymal stem cells under certain conditions and have a positive effect on diabetic wound healing.

Biological characterization of dehydrated amniotic membrane allograft: Mechanisms of action and implications for wound care

There is a growing clinical demand in the wound care market to treat chronic wounds such as diabetic foot ulcers. Advanced cell and tissue-based products (CTPs) are often used to address challenging chronic wounds where healing has stalled. These products contain active biologics such as growth factors and cytokines as well as structural components that support and stimulate cell growth and assist in tissue regeneration. This study addresses the in vitro biologic effects of a clinically available dehydrated amniotic membrane allograft (DAMA). The broad mechanism of action results from DAMA's biologic composition that leads to stimulation of cell migration cell proliferation, and reduction of pro-inflammatory cytokines. Results show that DAMA possesses growth factors and cytokines such as EGF, FGF, PDGFs, VEGF, TGF-β, IL-8, and TIMPs 1 and 2. Furthermore, in vitro experiments demonstrate that DAMA stimulates cell proliferation, cell migration, secretion of collagen type I, and the reduction of pro-inflammatory cytokines IL-1β, IL-6, and TNF-α. This study findings are consistent with the clinical benefits previously published for DAMA and other CTPs in chronic wounds suggesting that the introduction of DAMA to non-healing, complex wounds helps to improve the wound milieu by providing essential structural components, cytokines, and growth factors to create an appropriate environment for wound healing.

Use of an epidermal growth factor-infused foam dressing in a complicated case of Adams-Oliver syndrome

Adams-Oliver syndrome is a rare disorder with varying degrees of scalp and cranial bone defects as well as limb anomalies, which can range from mild to more pronounced manifestations. In mild cases, closure of these defects can be achieved with a conservative approach. However, surgical closure is recommended in cases where the defect is extensive and includes cranial involvement. Several complicated cases of Adams-Oliver syndrome have been reported, in which flap failures were encountered and other alternatives had to be used to close critical scalp defects. Here, the case of a 4-year-old child with Adams-Oliver syndrome and a complex cranial defect with exposed titanium mesh is described. The patient was successfully treated with epidermal growth factor (EGF) infused foam dressings and subsequent split-thickness skin grafting. The EGF has been highlighted for its essential role in dermal wound repair through the stimulation of the proliferation and migration of keratinocytes, and showed accelerated wound healing when used in partial or full-thickness skin wounds.

Gypenoside LXXV Promotes Cutaneous Wound Healing In Vivo by Enhancing Connective Tissue Growth Factor Levels Via the Glucocorticoid Receptor Pathway

Cutaneous wound healing is a well-orchestrated event in which many types of cells and growth factors are involved in restoring the barrier function of skin. In order to identify whether ginsenosides, the main active components of Panax ginseng, promote wound healing, the proliferation and migration activities of 15 different ginsenosides were tested by MTT assay and scratched wound closure assay. Among ginsenosides, gypenoside LXXV (G75) showed the most potent wound healing effects. Thus, this study aimed to investigate the effects of G75 on wound healing in vivo and characterize associated molecular changes. G75 significantly increased proliferation and migration of keratinocytes and fibroblasts, and promoted wound closure in an excision wound mouse model compared with madecassoside (MA), which has been used to treat wounds. Additionally, RNA sequencing data revealed G75-mediated significant upregulation of connective tissue growth factor (CTGF), which is known to be produced via the glucocorticoid receptor (GR) pathway. Consistently, the increase in production of CTGF was confirmed by western blot and ELISA. In addition, GR-competitive binding assay and GR translocation assay results demonstrated that G75 can be bound to GR and translocated into the nucleus. These results demonstrated that G75 is a newly identified effective component in wound healing.

Fidgetin-Like 2 siRNA Enhances the Wound Healing Capability of a Surfactant Polymer Dressing

Microtubules (MTs) are intracellular polymers that provide structure to the cell, serve as railways for intracellular transport, and regulate many cellular activities, including cell migration. The dynamicity and function of the MT cytoskeleton are determined in large part by its regulatory proteins, including the recently discovered MT severing enzyme Fidgetin-like 2 (FL2). Downregulation of FL2 expression with small interfering RNA (siRNA) results in a more than twofold increase in cell migration rate in vitro as well as translates into improved wound-healing outcomes in in vivo mouse models. Here we utilized a commercially available surfactant polymer dressing (SPD) as a vehicle to deliver FL2 siRNA. To this end we incorporated collagen microparticles containing FL2 siRNA into SPD (SPD-FL2-siRNA) for direct application to the injury site. Topical application of SPD-FL2 siRNA to murine models of full-thickness excision wounds and full-thickness burn wounds resulted in significant improvements in the rate and quality of wound healing, as measured clinically and histologically, compared with controls. Wound healing occurred more rapidly and with high fidelity, resulting in properly organized collagen substructure. Taken together, these findings indicate that the incorporation of FL2 siRNA into existing treatment options is a promising avenue to improve wound outcomes.

Transforming Growth Factor Beta (TGFβ1) and Epidermal Growth Factor (EGF) as Biomarkers of Leishmania (V) braziliensis Infection and Early Therapeutic Response in Cutaneous Leishmaniasis: Studies in Hamsters

Introduction: In cutaneous leishmaniasis, the host immune response is responsible for the development of skin injuries but also for resolution of the disease especially after antileishmanial therapy. The immune factors that participate in the regulation of inflammation, remodeling of the extracellular matrix, cell proliferation and differentiation may constitute biomarkers of diseases or response to treatment. In this work, we analyzed the production of the growth factors EGF, TGFβ1, PDGF, and FGF during the infection by Leishmania parasites, the development of the injuries and the early response to treatment. Methodology: Golden hamsters were infected with L. (V) braziliensis. The growth factors were detected in skin scrapings and biopsies every 2 weeks after infected and then at day 7 of treatment with different drug candidates by RT-qPCR. The parasitic load was also quantified by RT-qPCR in skin biopsies sampled at the end of the study. Results: The infection by L. (V) braziliensis induced the expression of all the growth factors at day 15 of infection. One month after infection, EGF and TGFβ1 were expressed in all hamsters with inverse ratio. While the EGF and FGF levels decreased between day 15 and 30 of infection, the TGFβ1 increased and the PGDF levels did not change. The relative expression of EGF and TGFβ1 increased notably after treatment. However, the increase of EGF was associated with clinical cure while the increase of TGFβ1 was associated with failure to treatment. The amount of parasites in the cutaneous lesion at the end of the study decreased according to the clinical outcome, being lower in the group of cured hamsters and higher in the group of hamsters that had a failure to the treatment. Conclusions: A differential profile of growth factor expression occurred during the infection and response to treatment. Higher induction of TGFβ1 was associated with active disease while the higher levels of EGF are associated with adequate response to treatment. The inversely EGF/TGFβ1 ratio may be an effective biomarker to identify establishment of Leishmania infection and early therapeutic response, respectively. However, further studies are needed to validate the utility of the proposed biomarkers in field conditions.

Wound healing in the eye: Therapeutic prospects

In order to maintain a smooth optical surface the corneal epithelium has to continuously renew itself so as to maintain its function as a barrier to fluctuating external surroundings and various environmental insults. After trauma, the cornea typically re-epithelializes promptly thereby minimizing the risk of infection, opacification or perforation. A persistent epithelial defect (PED) is usually referred to as a non-healing epithelial lesion after approximately two weeks of treatment with standard therapies to no avail. They occur following exposure to toxic agents, mechanical injury, and ocular surface infections and are associated with significant clinical morbidity in patients, resulting in discomfort or visual loss. In the case of deeper corneal injury and corneal pathology the wound healing cascade can also extend to the corneal stroma, the layer below the epithelium. Although significant progress has been made in recent years, pharmaco-therapeutic agents that promote corneal healing remain limited. This article serves as a review of current standard therapies, recently introduced alternative therapies gaining in popularity, and a look into the newest developments into ocular wound healing.

Local effects of epidermal growth factor on the wound healing in esophageal anastomosis: An experimental study

OBJECTIVE

In this study with the experimental model of primary repair of esophageal atresia(EA), we investigated the effects of the epidermal growth factor(EGF) on wound healing in the anastomosis of EA.

MATERIALS AND METHODS

Forty rabbits that were performed a resection of a 1-cm segment of the cervical esophagus followed by the end-to-end anastomosis were divided into four groups. Group I (7-day group) and III (21-day group), the control groups, had no EGF applied to the anastomosis. In group II (7-day group) and group III (21-day group), all around the anastomoses were locally covered with 100 μg/kg EGF. Group 1, 2 and 3, 4 were sacrificed on the 7th and 21st day, respectively. We investigated and compared with bursting pressure, vascularization around the anastomotic line by histopathology, inflammation, and fibroblast granulation as well as hydroxyproline level by biochemical.

RESULTS

No significant difference was found at vascularization and inflammation between all of the groups (p > 0.05). Considering the critical parameters of the groups, at bursting pressure difference was found between group 1 and 2 as well as 3 and (p < 0.05). At fibroblast granulation and hydroxyproline level, no difference was found between group 1 and 2 (p > 0.05) but the difference between group 3 and 4 (p < 0.05).

CONCLUSION

EGF might be useful in preventing anastomotic leakage of esophageal atresia in primary anastomosis of esophageal atresia by accelerating wound healing process and increasing the stability of the anastomotic line.

In vitro evaluation of a basic fibroblast growth factor-containing hydrogel toward vocal fold lamina propria scar treatment

Scarring of the vocal fold lamina propria can lead to debilitating voice disorders that can significantly impair quality of life. The reduced pliability of the scar tissue-which diminishes proper vocal fold vibratory efficiency-results in part from abnormal extracellular matrix (ECM) deposition by vocal fold fibroblasts (VFF) that have taken on a fibrotic phenotype. To address this issue, bioactive materials containing cytokines and/or growth factors may provide a platform to transition fibrotic VFF within the scarred tissue toward an anti-fibrotic phenotype, thereby improving the quality of ECM within the scar tissue. However, for such an approach to be most effective, the acute host response resulting from biomaterial insertion/injection likely also needs to be considered. The goal of the present work was to evaluate the anti-fibrotic and anti-inflammatory capacity of an injectable hydrogel containing tethered basic fibroblast growth factor (bFGF) in the dual context of scar and biomaterial-induced acute inflammation. An in vitro co-culture system was utilized containing both activated, fibrotic VFF and activated, pro-inflammatory macrophages (MΦ) within a 3D poly(ethylene glycol) diacrylate (PEGDA) hydrogel containing tethered bFGF. Following 72 h of culture, alterations in VFF and macrophage phenotype were evaluated relative to mono-culture and co-culture controls. In our co-culture system, bFGF reduced the production of fibrotic markers collagen type I, α smooth muscle actin, and biglycan by activated VFF and promoted wound-healing/anti-inflammatory marker expression in activated MΦ. Cumulatively, these data indicate that bFGF-containing hydrogels warrant further investigation for the treatment of vocal fold lamina propria scar. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 1258-1267, 2018.

Effects of fibroblast growth factor-2 on cell proliferation of cementoblasts

Background/purpose

Fibroblast growth factor (FGF)-2 is known as a signaling molecule that induces tissue regeneration. Little is known about the effect of FGF-2 on cementoblasts for periodontal and periapical regeneration. The aim of this study was to investigate the effects of FGF-2 on murine immortalized cementoblast cell line (OCCM.30).

Materials and methods

Cell growth and proliferation was judged by using alamar blue reduction assay. Flow cytometry analysis was used to evaluate Stro-1 positive cells expression with or without FGF-2. Western blot was used to evaluate the expression of phosphorylated serine–threonine kinase Akt (p-Akt) and extracellular signal-regulated protein kinase (p-ERK) in cementoblasts.

Results

FGF-2 was found to increase cell growth in a dose-dependent manner (P < 0.05). The concentration of 10 ng/mL FGF-2 enhanced cell proliferation in a time-dependent manner (P < 0.05). In addition, 10 ng/mL FGF-2 significantly increased the number of Stro-1 positive cells in the first 24 hours (P < 0.05). Moreover, 10 ng/mL FGF-2 was found to upregulate p-Akt and p-ERK in a time-dependent manner (P < 0.05).

Conclusion

Taken together, FGF-2 could increase cementoblast growth, proliferation, and Stro-1 positive cells. These enhancements are associated with the upregulation of p-Akt and p-ERK expression. The application of FGF-2 may provide benefit for periodontal and periapical regeneration during the early phase of wound healing.

A Heparin-Mimicking Block Copolymer Both Stabilizes and Increases the Activity of Fibroblast Growth Factor 2 (FGF2)

Fibroblast growth factor 2 (FGF2) is a protein involved in cellular functions in applications such as wound healing and tissue regeneration. Stabilization of this protein is important for its use as a therapeutic since the native protein is unstable during storage and delivery. Additionally, the ability to increase the activity of FGF2 is important for its application, particularly in chronic wound healing and the treatment of various ischemic conditions. Here we report a heparin mimicking block copolymer, poly(styrenesulfonate-co-poly(ethylene glycol) methyl ether methacrylate)-b-vinyl sulfonate) (p(SS-co-PEGMA)-b-VS, that contains a segment that enhances the stability of FGF2 and one that binds to the FGF2 receptor. The FGF2 conjugate retained activity after exposure to refrigeration (4 °C) and room temperature (23 °C) for 7 days, while unmodified FGF2 was inactive after these standard storage conditions. A cell study performed with a cell line lacking native heparan sulfate proteoglycans indicated that the conjugated block copolymer facilitated binding of FGF2 to its receptor similar to the addition of heparin to FGF2. A receptor-based enzyme-linked immunosorbant assay (ELISA) confirmed the results. The conjugate also increased the migration of endothelial cells by 80% compared to FGF2 alone. Additionally, the FGF2-p(SS-co-PEGMA)-b-VS stimulated endothelial cell sprouting 250% better than FGF2 at low concentration. These data verify that this rationally designed protein-block copolymer conjugate enhances receptor binding, cellular processes such as migration and tube-like formation, and stability, and suggest that it may be useful for applications in biomaterials, tissue regeneration, and wound healing.

Potential Role of Growth Factors and Extracellular Matrix in Wound Healing after Laryngotracheal Reconstruction

Laryngotracheal reconstruction (LTR) has been used for more than 20 years to treat infants and children with subglottic stenosis. Results after pediatric LTR have been satisfactory; however, approximately 10% of children have recurrent airway narrowing after LTR. The purpose of our study was to determine whether a correlation existed between specific growth factors and extracellular matrix in patients with adequate wound healing capability as compared with patients with poor wound healing capability. Histologic sections from 27 patients who underwent LTR were cut, and immunohistochemical staining was performed for transforming growth factor-β, platelet-derived growth factor, fibronectin, tenascin, transforming growth factor-α, and vascular endothelial growth factor. Results showed that patients with adequate wound healing capability had a positive correlation with vasculature fibronectin, vasculature tenascin, and stromal fibronectin. Patients with poor wound healing capability had a positive correlation with stromal vascular endothelial growth factor.

Platelet gel: a new therapeutic tool with great potential

Chronic wounds, such as diabetic foot ulcers, represent a serious clinical problem for patients and clinicians. Management of these wounds has a strong economic impact worldwide. Complications resulting from injuries are a frequent cause of morbidity and mortality. Chronic wounds lead to infections, painful dressings and prolonged hospitalisation. This results in poor patient Quality of Life and in high healthcare costs. Platelet concentrates (PC) are defined as autologous or allogeneic platelet derivatives with a platelet concentration higher than baseline. PC are widely used in different areas of Regenerative Medicine in order to enhance wound healing processes; they include platelet-rich plasma (PRP), platelet gel (PG), platelet-rich fibrin (PRF), serum eye drops (E-S), and PRP eye drops (E-PRP). This review highlights the use of platelet-rich plasma (PRP) and platelet gel (PG) preparation for clinical use.

Autologous adipose-derived stem cells: Basic science, technique, and rationale for application in ulcer and wound healing

Objectives The present review represents a translational boundary between basic research and surgery, particularly focusing on the promising application of adipose-derived stem cells harvested intra-operatively during debridement of venous leg ulcers. Methods We reviewed 830 out of 5578 articles on MEDLINE starting from 1997 and sorted by the relevance option. Results The technique currently used for adipose-derived stem cells intra-operative harvesting is presented, including a safety evaluation on a cohort of 5089 revised patients who underwent plastic surgery and maxillo-facial surgical procedures. Complications were reported in 169 cases (3.3%). One hundred and forty-one (2.77%) patients were classified as having minor complications, specifically: nodularity/induration 93 (1.83%), dysesthesia 14 (0.26%), hematoma 12 (0.23%), superficial infection 11 (0.21%), pain 7 (0.13%), poor cosmesis 3 (0.06%), and abnormal breast secretion 1 (0.02%), while 28 patients (0.55%) were classified as having major complications, specifically: deep infection 22 (0.43%), sepsis 3 (0.06%), abdominal hematoma 2 (0.04%), and pneumothorax 1 (0.02%). Application of cell therapy in venous leg ulcer is currently used only for patients not responding to the standard treatment. The review shows the lack of randomized clinical trials for application of adipose-derived stem cells among treatments for venous leg ulcer. Finally, adipose-derived stem cells implantation at the wound site promotes a new tissue formation rich in vascular structures and remodeling collagen. Conclusion Adipose-derived stem cells strategy represents a great opportunity for the treatment of chronic wounds, due to the simplicity of the technique and the application of cell treatment in the operating room immediately following debridement. However, clinical studies and data from randomized trials are currently lacking.

Evaluation of the efficacy of platelet-rich plasma and platelet-rich fibrin in alveolar defects after removal of impacted bilateral mandibular third molars

AIM AND OBJECTIVES

This study attempted the evaluation of the efficacy of platelet-rich plasma (PRP) and platelet-rich fibrin (PRF) in alveolar defects after removal of bilateral mandibular third molars.

MATERIALS AND METHODS

A total of 30 patients reporting to Department of Oral and Maxillofacial Surgery and having bilateral mandibular third molar impaction in both male and female aged between 18 and 30 years were included in this study. PRF and PRP were placed in extraction site and recalled at 2(nd), 4(th), and 6(th) month postoperatively. Data were statistically analyzed using IBM SPSS software for Windows, version 19.0. IBM Corp., Armonk, NY, USA.

RESULTS

This study showed decreased probing depth in PRF group compared to PRP and control one. This signifies a better soft tissue healing of extraction sockets with PRF as compared to the PRP and the control group and increase in the bone density highlights the use of PRP and PRF certainly as a valid method in inducing hard tissue regeneration.

CONCLUSION

This study indicates a definite improvement in the periodontal health distal to second molar after third molar surgery in cases treated with PRF as compared to the PRP group and control group. Hence, PRP and PRF can be incorporated as an adjunct to promote wound healing and osseous regeneration in mandibular third molar extraction sites.

Hamstrings anterior cruciate ligament reconstruction with and without platelet rich fibrin matrix

PURPOSE

Anterior cruciate ligament (ACL) rupture is the most common complete ligamentous injury in the knee. Many studies explored ACL graft integration and maturation, but only a few assessed the application of platelet rich fibrin matrix (PRFM) as augmentation for ACL reconstruction. The main aim of this study was to test the PRFM augmentation in terms of graft-bone integration and knee stability. The secondary aim was to investigate patient-reported functional status.

METHODS

Prospective evaluation has been done in two consecutive series of patients who underwent ACL reconstruction with semitendinosus and gracilis (STG) grafts: 14 patients were operated with PRFM augmentation and 14 patients without PRFM augmentation. Objective clinical evaluation (Rolimeter) and MRI evaluation were performed at 1 year from surgery. Subjective evaluation (IKDC) was performed pre-operatively and at 6 months, 1 and 2 years from surgery.

RESULTS

A statistically significant difference was not detected between the two groups in terms of MRI and objective clinical evaluation, although PRFM-augmented patients showed a statistically significant higher clinical improvement.

CONCLUSIONS

The procedure described for PRFM augmentation in ACL STG reconstruction does not improve radiologic graft integration and knee stability after 1 year and should not be used by clinicians to this purpose. However, it may result in a short-term improvement of patient-reported knee function, and future research should focus on further developing PRP treatment to optimize ACL clinical outcome.

LEVEL OF EVIDENCE

III.

Efficacy of gelatin gel sheets sustaining epidermal growth factor for murine skin defects

BACKGROUND

Epidermal growth factor (EGF) plays an important role in wound healing. However, EGF must be applied daily due to rapid inactivation in vivo. We investigated the sustained release of EGF from gelatin gel sheets (GGSs) and the efficacy of GGSs impregnated with EGF for promoting wound healing.

MATERIALS AND METHODS

GGSs impregnated with EGF were prepared by cross-linking via glutaraldehyde to gelatin solution containing EGF. The sustained release of EGF and the bioactivity of released EGF were evaluated. Then, three kinds of GGSs containing NSS (normal saline solution; NSS group), 2.5 μg of EGF (EGF-L group), or 25 μg of EGF (EGF-H group) were applied to full-thickness skin defects created on the backs of mice. The wounds covered with polyurethane film without GGS were used as a control (PUF group). The wound area, neoepithelium length, regenerated granulation tissue, and newly formed capillaries were evaluated.

RESULTS

EGF was sustained and released from GGS as it degraded. The bioactivity of released EGF was confirmed. EGF-L group promoted the neoepithelium length, regenerated granulation tissue, and newly formed capillaries compared with those in the PUF and NSS groups. The area of regenerated granulation tissue in the NSS group (week 1: 2.6 + 0.2 mm(2), week 2: 2.8 + 0.3 mm(2)) was larger than that in the PUF group (week 1: 0.6 + 0.1 mm(2), week 2: 1.0 + 0.1 mm(2)). The area of newly formed capillaries in the EGF-L group (9967 + 1903 μm(2)) was larger than that of the EGF-H group (3485 + 1050 μm(2)).

CONCLUSIONS

GGSs impregnated with EGF-L showed promising results regarding wound healing.

Platelet growth factors from allogeneic platelet-rich plasma for clinical improvement in split-thickness skin graft

Background and objectives:

Platelets are a source of numerous growth factors which facilitate repair and healing. Thus platelet rich plasma has been increasingly used as a treatment modality in the field of reconstructive surgeries for wound healing. This preliminary study was carried out to explore whether platelet growth factors from platelet rich plasma could be used for enhancement of split thickness skin graft survival.

Materials and Methods:

Twenty patients (13 males and 7 females) requiring split thickness skin graft for various clinical reasons were enrolled in the study. Platelet rich plasma was collected by apheresis and frozen at −80° C. It was thawed at room temperature immediately before its intended application. PRP was applied only on one half of the wound, while another half served as control. Patient was followed for 6 weeks. The effect was assessed at first dressing in terms of graft uptake and subsequently as time taken for complete healing.

Results:

There was 100% uptake of the graft in the area where platelet rich plasma was applied. In the control area, there was complete graft loss in 4 cases, partial loss in 7 cases and complete uptake in 9 cases.

Conclusion:

This study demonstrated promising results on application of PRP to split thickness skin grafts. Further randomized studies with greater sample size may be undertaken to establish platelet rich plasma as a validated treatment modality.

Efficacy Study of Broken Rice Maltodextrin in In Vitro Wound Healing Assay

Maltodextrins that contain both simple sugars and polymers of saccharides have been widely used as ingredients in food products and pharmaceutical delivery systems. To date, no much work has been reported on the applications of maltodextrin from broken rice (RB) sources. Therefore, the objective of this work was to investigate the in vitro wound healing efficacy of RB maltodextrin at different conditions. Wounds treated with lower dextrose equivalent (DE) range (DE 10–14) of maltodextrins at a concentration of 10% obtained from RB were found to be able to heal the wounds significantly faster (p < 0.01) than maltodextrin with higher DE ranges (DE 15–19 and DE 20–24) and concentrations of 5% and 20%. The findings from both BrdU and MTT assay further confirmed its wound healing properties as the NIH 3T3 fibroblast wounded cells were able to proliferate without causing cytotoxic effect when wounded cell was treated with maltodextrin. All these findings indicated that the RB maltodextrin could perform better than the commercial maltodextrin at the same DE range. This study showed that RB maltodextrins had better functionality properties than other maltodextrin sources and played a beneficial role in wound healing application.

Effects of kynurenine on CD3+ and macrophages in wound healing

As prolongation of the inflammation phase in a healing process frequently leads to wound impairment, here we queried whether kynurenine (Kyn) could modulate this phase of wound healing. To address this, a protein microarray, quantitative polymerase chain reaction (qPCR), flow cytometry for immune cells and immune cell proliferation in the presence and absence of Kyn were conducted and compared. The result of a protein microarray revealed that the expression of 12 pro-inflammatory cytokines and chemokines was modulated in Kyn-treated mouse splenocytes as compared with those of control. These findings were then evaluated by conducting a qPCR for the gene expression of these factors and showed a significant reduction in the gene expression of majority of these cytokines and chemokines (interleukin [IL]-2, IL-17, C-X-C motif chemokine ligand [CXCL] 10, CXCL1, C-C motif ligand [CCL] 12, CXCL9, CCL4, CXCL2, and CCL5) in response to Kyn treatment. To test the anti-inflammatory effect of Kyn in an animal model, dorsal surface wounds were generated in a mouse model and wounds received daily topical application of either nothing (control), dermal cream (second control), or Kyn cream using uninjured skin tissue as another control. The wounded tissues were harvested on days 3, 6, and 10 postwounding. As anticipated, the results of fluorescence-activated cell sorting analysis revealed that upon wounding, the number of total infiltrated CD3+ cells and macrophages (CD11b+) significantly increased on day 3, peaked on day 6, and reduced on day 10 post-wounding. Interestingly, as compared with those of uninjured and dermal cream alone-treated wounds, Kyn treatment significantly reduced the number of infiltrated CD3+ cells, but not CD11b+ cells, at different time intervals examined. These findings collectively suggest that Kyn, as a small molecule, can potentially be used to overcome the difficulties associated with persistency of inflammation in healing wounds.

Determining the Effect of Preparation and Storage: An Effort to Streamline Platelet Components as a Source of Growth Factors for Clinical Application

BACKGROUND

In the present study, different methods for preparation of platelet-rich plasma (PRP) are investigated in order to standardize the component in terms of growth factor content. The effects of concentration technique and storage duration are also analyzed.

METHODS

PRP was collected from 40 donors by plateletpheresis as well as by the buffy coat and tube method. Concentration of growth factors was performed using double freeze thaw- and CaCl2-induced degranulation techniques. Growth factor estimation was performed using ELISA.

RESULTS

The levels of growth factors were highest in PRP from buffy coat, moderately lower in plasma gained by plateletpheresis and lowest in that obtained by the tube method. Mean levels of platelet-derived growth factors (PDGF) AB and BB are significantly higher when CaCl2 was used for concentrating the growth factors. The mean levels of transforming growth factor β1 and insulin-like growth factor I were higher when applying the double freeze thaw technique. There was a substantial decline in the levels of growth factors during storage.

CONCLUSION

The buffy coat method is suitable as preparation method for PRP in most settings. The double freeze thaw technique is better suited as concentration technique as it causes lysis of both platelets and white blood cells for releasing growth factors and is easier to perform. Growth factors are not stable in plasma, thus PRP should be frozen immediately after preparation.

Momordica charantia ointment accelerates diabetic wound healing and enhances transforming growth factor-β expression

OBJECTIVE

Transforming growth factor-β (TGF-β) plays an important role in wound healing. Delayed wound healing is a consequence of diabetes, leading to high morbidity and poor quality of life. Momordica charantia (MC) fruit possesses anti-diabetic and wound healing properties. This study aimed to explore the changes in TGF-β expression in diabetic wounds treated with topical MC fruit extract.

METHODS

Fifty-six male Sprague-Dawley rats were divided into a normal control group and five diabetic groups of ten rats each. Intravenous streptozotocin (50mg/kg) was given to induce diabetes in the diabetic groups. Full thickness excision wounds were created on the thoracodorsal region of the animals, and these wounds were then treated with vehicle, MC powder, MC ointment and povidone ointment or ointment base for ten days. Wound healing was determined by the rate of wound closure, total protein content and TGF-β expression in the wounds, and histological observation.

RESULTS

Diabetic groups showed delayed wound closure rates compared to the control group. The wound closure rate in the MC ointment group was significantly faster than that of the untreated diabetic group (p<0.05). The MC ointment group also showed intense TGF-β expression and a high level of total protein content.

CONCLUSION

MC ointment has a promising potential for use as an alternative topical medication for diabetic wounds. This work has shown that it accelerates wound healing in diabetic rats, and it is suggested here that this occurs by enhancing TGF-β expression. Further work is recommended to explore this effect.

The basic science of platelet-rich plasma (PRP): what clinicians need to know

Platelet-rich plasma (PRP) has been advocated for the biological augmentation of tissue healing and regeneration through the local introduction of increased levels (above baseline) of platelets and their associated bioactive molecules. In theory, the increased levels of autologous growth factors and secretory proteins provided by the concentrated platelets may enhance the wound healing process, especially in degenerative tissues or biologically compromised individuals. Although PRP has been increasingly utilized in the treatment of a variety of sports-related injuries, improvements in healing and clinical outcomes have not been universally reported. One reason for this may be the fact that all PRP preparations are not the same. Variations in the volume of whole blood taken, the platelet recovery efficacy, the final volume of plasma in which the platelets are suspended, and the presence or absence of white blood cells, and the addition of exogenous thrombin to activate the platelets or calcium chloride to induce fibrin formation, can all affect the character and potential efficacy of the final PRP product. This article will review the basic principles involved in creating PRP and examine the potential basic scientific significance of the individual blood components contained in the various forms of PRP currently used in sports medicine.

Production of functional active human growth factors in insects used as living biofactories

Growth factors (GFs) are naturally signalling proteins, which bind to specific receptors on the cell surface. Numerous families of GFs have already been identified and remarkable progresses have been made in understanding the pathways that these proteins use to activate/regulate the complex signalling network involved in cell proliferation or wound healing processes. The bottleneck for a wider clinical and commercial application of these factors relay on their scalable cost-efficient production as bioactive molecules. The present work describes the capacity of Trichoplusia ni insect larvae used as living bioreactors in combination with the baculovirus vector expression system to produce three fully functional human GFs, the human epidermal growth factor (huEGF), the human fibroblast growth factor 2 (huFGF2) and the human keratinocyte growth factor 1 (huKGF1). The expression levels obtained per g of insect biomass were of 9.1, 2.6 and 3mg for huEGF, huFGF2 and huKGF1, respectively. Attempts to increase the productivity of the insect/baculovirus system we have used different modifications to optimize their production. Additionally, recombinant proteins were expressed fused to different tags to facilitate their purification. Interestingly, the expression of huKGF1 was significantly improved when expressed fused to the fragment crystallizable region (Fc) of the human antibody IgG. The insect-derived recombinant GFs were finally characterized in terms of biological activity in keratinocytes and fibroblasts. The present work opens the possibility of a cost-efficient and scalable production of these highly valuable molecules in a system that favours its wide use in therapeutic or cosmetic applications.