Wound Skin Tissue Research Articles

Surface modification of nanofibrous polycaprolactone/gelatin composite scaffold by collagen type I grafting for skin tissue engineering

In the present study, a tri-polymer polycaprolactone (PCL)/gelatin/collagen type I composite nanofibrous scaffold has been fabricated by electrospinning for skin tissue engineering and wound healing applications. Firstly, PCL/gelatin nanofibrous scaffold was fabricated by electrospinning using a low cost solvent mixture [chloroform/methanol for PCL and acetic acid (80% v/v) for gelatin], and then the nanofibrous PCL/gelatin scaffold was modified by collagen type I (0.2–1.5wt.%) grafting. Morphology of the collagen type I-modified PCL/gelatin composite scaffold that was analyzed by field emission scanning electron microscopy (FE-SEM), showed that the fiber diameter was increased and pore size was decreased by increasing the concentration of collagen type I. Fourier transform infrared (FT-IR) spectroscopy and thermogravimetric (TG) analysis indicated the surface modification of PCL/gelatin scaffold by collagen type I immobilization on the surface of the scaffold. MTT assay demonstrated the viability and high proliferation rate of L929 mouse fibroblast cells on the collagen type I-modified composite scaffold. FE-SEM analysis of cell-scaffold construct illustrated the cell adhesion of L929 mouse fibroblasts on the surface of scaffold. Characteristic cell morphology of L929 was also observed on the nanofiber mesh of the collagen type I-modified scaffold. Above results suggest that the collagen type I-modified PCL/gelatin scaffold was successful in maintaining characteristic shape of fibroblasts, besides good cell proliferation. Therefore, the fibroblast seeded PCL/gelatin/collagen type I composite nanofibrous scaffold might be a potential candidate for wound healing and skin tissue engineering applications.

In Vivo and ex Vivo Approaches to Studying the Biomechanical Properties of Healing Wounds in Rat Skin

An evaluation of wound mechanics is crucial in reflecting the wound healing status. The present study examined the biomechanical properties of healing rat skin wounds in vivo and ex vivo. Thirty male Sprague-Dawley rats, each with a 6 mm full-thickness circular punch biopsied wound at both posterior hind limbs were used. The mechanical stiffness at both the central and margins of the wound was measured repeatedly in five rats over the same wound sites to monitor the longitudinal changes over time of before wounding, and on days 0, 3, 7, 10, 14, and 21 after wounding in vivo by using an optical coherence tomography-based air-jet indentation system. Five rats were euthanized at each time point, and the biomechanical properties of the wound tissues were assessed ex vivo using a tensiometer. At the central wound bed region, the stiffness measured by the air-jet system increased significantly from day 0 (17.2%), peaked at day 7 (208.3%), and then decreased progressively until day 21 (40.2%) as compared with baseline prewounding status. The biomechanical parameters of the skin wound samples measured by the tensiometer showed a marked reduction upon wounding, then increased with time (all p < 0.05). On day 21, the ultimate tensile strength of the skin wound tissue approached 50% of the normal skin; while the stiffness of tissue recovered at a faster rate, reaching 97% of its prewounded state. Our results suggested that it took less time for healing wound tissues to recover their stiffness than their maximal strength in rat skin. The stiffness of wound tissues measured by air-jet could be an indicator for monitoring wound healing and contraction.

Preparation and characteristic of a sodium alginate/carboxymethylated bacterial cellulose composite with a crosslinking semi‐interpenetrating network

ABSTRACTA novel ionic crosslinking sodium alginate (SA)/carboxymethylated bacterial cellulose (CM‐BC) composite with a semi‐interpenetrating polymer network (semi‐IPN) structure was developed in this study. The composite was prepared through the blending of an SA gel with CM‐BC then crosslinking by Ca2+ followed by a freeze‐drying process. Scanning electron microscopy showed the composite matrix organized in a three‐dimensional network of CM‐BC interpenetrated against SA molecular chains with a quantity of calcium alginate microspheres upon the surface. The swelling ratios of the composite were enhanced by 183, 198, and 212% with the supplementation of CM‐BC weight fractions of 25, 50, and 75%, respectively; the swelling ratios changed with changing pH. The tensile modulus, tensile strength, and elongation at break of SA were enhanced by 165, 152, and 188%, respectively, with the addition of 50 wt % CM‐BC. This study demonstrated that the semi‐IPN structure dramatically changed the swelling and mechanical properties of the composite, and the semi‐IPN will be a promising candidate for biomedical applications such as wound dressings and skin tissue engineering. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 39848.

Effect of Aminoguanidine Intervention on Neutrophils in Diabetes Inflammatory Cells Wound Healing

To explore aminoguanidine (AG) effect on neutrophil functions and associated signal transduction way in diabetic rats wound healing. Sprague-Dawley (SD) rats were divided into 3 groups, Group A (control+burns), Group B (diabetes+burns), Group C (diabetes+burns+AG). Wound skin tissue was harvested at 6h, 24h and 36h after trauma, and then immunohistochemistry was used to detect AGE (advanced glycation end products) contents and RAGE (receptor of AGE) expression. Western blotting was applied to detect RAGE and NF-κB. Oxidative stress changes were detected by colorimetry. Inflammatory cytokines were determined by ELIASA and cell apoptosis by TUNEL. Pathological changes were analyzed by hematoxylin-eosin (HE) staining. In the wound tissue of Group C, compared to that in Group B, AGE content, RAGE expression level, NF-κB level declined, and MPO (myeloperoxidase) decreased at 36h; TNFα, IL-8, H2O2, GSH-Px (Glutathione peroxidse), and MDA (malondialdehyde) levels increased; dense post-traumatic inflammation belt formed obviously. AG for prophylactic use can promote the migration and respiratory burst of neutrophils markedly, and help to restore the functions of neutrophil; and the abnormal secretion of inflammation cytokines can be corrected partly. Blocking AGE deposition and promoting microenvironment were effective ways for diabetic wound healing.

Click chemistry approach for fabricating PVA/gelatin nanofibers for the differentiation of ADSCs to keratinocytes

Every year, millions of people suffer from dermal wounds caused by heat, fire, chemicals, electricity, ultraviolet radiation or disease. Tissue engineering and nanotechnology have enabled the engineering of nanostructured materials to meet the current challenges in skin treatments owing to such rising occurrences of accidental damages, skin diseases and defects. The abundance and accessibility of adipose derived stem cells (ADSCs) may prove to be novel cell therapeutics for skin regeneration. The nanofibrous PVA/gelatin/azide scaffolds were then fabricated by electrospinning using water as solvent and allowed to undergo click reaction. The scaffolds were characterized by SEM, contact angle and FTIR. The cell-scaffold interactions were analyzed by cell proliferation and the results observed that the rate of cell proliferation was significantly increased (P ≤ 0.05) on PVA/gelatin/azide scaffolds compared to PVA/gelatin nanofibers. In the present study, manipulating the biochemical cues by the addition of an induction medium, in combination with environmental and physical factors of the culture substrate by functionalizing with click moieties, we were able to drive ADSCs into epidermal lineage with the development of epidermis-like structures, was further confirmed by the expression of early and intermediate epidermal differentiation markers like keratin and filaggrin. This study not only provides an insight into the design of a site-specific niche-like microenvironment for stem cell lineage commitment, but also sheds light on the therapeutic application of an alternative cell source-ADSCs, for wound healing and skin tissue reconstitution.

Detection of galectin-3 and localization of advanced glycation end products (AGE) in human chronic skin wounds.

The matricellular protein galectin-3 (Gal-3) is upregulated in excisional skin repair in rats where it has been shown to modulate the inflammatory phase of repair. Recent research into kidney pathology has implicated Gal-3 as a receptor for advanced glycation end products (AGE), resulting in the binding and clearance of these molecules. AGEs are thought to contribute to defective skin repair in diabetic patients as well as a result of the normal aging process. However, the distribution and localization of Gal-3 and AGEs has never been performed in human chronic skin wound tissue. Using immunohistochemistry, the localization of Gal-3 and AGEs in tissue isolated from chronic wounds and non-involved skin from the same patient was investigated. Of the 16 patients from which tissue was isolated, 13 had type II diabetes, one had type I diabetes and 2 patients without diabetes were also examined. In non-involved dermis, Gal-3 was detected strongly in the epidermis and in the vasculature. However, at the wound edge and in the wound bed, the level of Gal-3 labelling was greatly reduced in both the epidermis and vasculature. Labelling of serial sections for Gal-3 and AGE demonstrated that where Gal-3 immunoreactivity is reduced in the epidermis and vasculature, there is a concomitant increase in the level of AGE staining. Interestingly, similar labelling patterns were evident in diabetic and non-diabetic patients. The results from our study demonstrate an inverse correlation between Gal-3 and AGEs localization, suggesting that Gal-3 may protect against accumulation of AGEs in wound healing.

Exploring the dermal “template effect” and its structure

Scar formation is the problem for clinic surgery. Recent studies showed that the scar formation was closely related to the dermal defect. Three-dimensional (3-d) structures of dermal tissues act as a template to modulate cell functions that are essential the regeneration of skin structure and function. The dermal tissue's integrity and continuity is a prerequisite for repair to take place. Loss of the dermal tissue integrity and continuity due to trauma leads to a lack of the template effect, which may be one important mechanism that hinders the recovery of cell function, resulting in scar formation. These studies give us two questions: what is the three-dimensional (3-d) structure of the dermal tissue? How do the tissues form? Up to now, it is well known that the molecular structure of collagen, the micro-structure of microfibril, however, the mesoscopic structure of dermal tissues is still unclear. Our recently rudimentary studies showed the problem might be resolved by phase-contrast micro-tomography with synchrotron radiation, which is likely to open new avenues for further investigations on wound regeneration and skin tissue engineering.

Identification of highly concentrated dextrose solution (50% dextrose) extravasation and treatment—a clinical report

Treatment for significant hypoglycemia includes administration of dextrose containing agents, including 50% dextrose (D50%W) intravenously. Significant extravasation of D50%W can lead to complications, including skin and soft tissue injury, loss of limb, or death. The aim of this case report, using an interdisciplinary team approach, explores extravasation protocols as well as literature review, is to provide information about the proper use of hyaluronidase in patients with D50%W extravasations. A 46-year-old African American man presented to the emergency department (ED) after blood glucose level was initially 13 mg/dL. Emergency medical service established a large bore intravenous (IV) line in the right antecubital vein and administered a total of 50 g of D50%W. Upon arrival to the ED, the patient's level of consciousness had significantly improved. After arrival to the ED, the patient started complaining of pain in his right arm, near the site of the IV line insertion. On inspection, the IV site was grossly infiltrated. Hospital protocols for hyperosmolar infiltration were used. Extravasation is a common medical complication of infused medications and needs to be properly identified and treated. The multitude of skills from nursing, medicine, and pharmacy ensures that extravasation is managed appropriately and effectively to ensure safety to patients. Recognition, communication, and awareness of the institutional guidelines on how to treat infiltration and extravasation should be encouraged in all ED and intensive care unit medical personnel who deal with a variety of infusions and IV medications that have serious implications if not treated correctly.

Abstract 4719: Exploratory biomarker program in Phase I clinical development of RG7155, a novel humanized anti-CSF-1R Mab, targeting Tumor Associated Macrophages (TAMs).

Abstract Early Phase I clinical development of RG7155, a humanized anti-CSF-1R monoclonal antibody binding to dimerization interface of CSF-1 receptor and inducing apoptosis in CSF-1R expressing macrophages is accompanied by an extensive biomarker program. Phase I biosampling aims to enable monitoring of mode of action, drug efficacy and potential tumor escape mechanisms by identifying response prediction and mechanistic efficacy markers and therefore to support optimal biological dose (OBD) definition and patient stratification for subsequent clinical testing. One biomarker hypothesis to support potential patient stratification assumes that response to treatment with RG7155 is enhanced in tumors with high CSF-1R positive macrophage infiltration and with high CSF-1 levels in the peripheral blood as the basis for tumor promoting macrophage recruitment and differentiation. The Phase I biomarker program comprises extensive biosampling including mandatory fresh baseline and on treatment tumor, skin biopsies as well as peripheral blood sampling to identify and monitor pharmacodynamic as well as mechanistic efficacy markers. Pre- and on-treatment tumor tissue analysis involves tumor infiltrating macrophage subtype characterization via CD68/CD163/CSF-1R/MHC II, CD4 and CD8 T cell assessment by multiplex IHC assays. In order to detect early tissue response prediction markers in surrogate tissue, wound associated macrophages (WAMs) are assessed in wounded skin tissue samples. Further, systematic collection of peripheral blood samples before and during RG7155 administration aims at identifying CSF-1R expressing target populations, other potential RG7155 susceptible immune cell populations by flow cytometry using CD8/CD4/CD3/CD45/MHC II/CD14/CD16/CD56/CD19 markers and an extended cytokine profiling by Luminex 17-plex panel. These markers will be correlated to direct anti-tumor effects assessed using KI67 IHC, FDG-PET, DC-Ultrasound and clinical response. Here we describe the development of the clinical biomarker strategy based on preclinical data and the specific assay developments, to enable the selection of the OBD, the correlation of TAM elimination with anti-tumor effects and the optimization of the biomarker sampling to minimize the burden of diagnostic procedures for patients in future clinical trials. Citation Format: Michael A. Cannarile, Kai Habben, Florian Heil, Ann-Marie Broeske, Dominik Ruettinger, Lisa Culton, Friedrich Feuerhake, Carola H. Ries. Exploratory biomarker program in Phase I clinical development of RG7155, a novel humanized anti-CSF-1R Mab, targeting Tumor Associated Macrophages (TAMs). [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 4719. doi:10.1158/1538-7445.AM2013-4719

Comparison of Complication Rates of Intramedullary Pin Fixation Versus Plating of Midshaft Clavicle Fractures in an Active Duty Military Population

Military service members have increased requirements of shoulder weight bearing to perform duties. Operative intervention has increased for treatment of displaced middle one-third clavicle fractures. Complications of operatively treated clavicle fixation have not been extensively studied. A retrospective, longitudinal cohort chart evaluation was conducted of all active duty members undergoing fixation of middle one-third clavicle fractures, for complications between intramedullary pin fixation and plate constructs. This review found 62 patients meeting inclusion criteria. Thirty-three patients underwent intramedullary pin fixation with Hagie pins and 31 patients underwent precontoured superior clavicle plate fixation of their middle one-third clavicle fractures. Complications included wound infection, skin and/or soft tissue irritation, and need for unplanned hardware removal. The overall complication rate was 31% in the plate fixation group versus 9% in the intramedullary pin group (p = .024). All patients achieved fracture union with return to duty; however, increased overall complications were seen in the plate fixation group.

Validation study of endogenous reference genes for normalization of quantitative real time PCR data in post mortem skin tissue

Gene expression profiling may provide insights into the molecular mechanisms underlying wound skin repair contributing to applications in the field of post mortem forensic wound age estimation. Quantitative real-time PCR (qPCR) is the most sensitive technique for gene expression studies but represents a complex procedure with several requirements for accurate data analysis. One of the major pre-requisites is the selection and validation of appropriate endogenous control genes for normalization in a given set of samples. In this study, the gene expression stabilities of ten endogenous controls ACTß, ß2M, PPIA, GAPDH, HPRT1, PGK1, SDHA, TBP, UBC, and YWHAZ were evaluated in two sets of samples: post mortem human wounded and unwounded skin tissue aimed for subsequent wound age estimation studies. The most stable genes were determined by calculating a gene expression normalization factor for each sample based on the geometric mean of the ten selected genes using the reference gene validation software, geNorm. In uninjured skin, the most stable endogenous controls were YWAZ, with the highest stability, followed by PGK1 and GAPDH. In the wounded samples, GAPDH was the most stable gene followed by PGK1, ACTß and HPRT1. Both groups revealed some differences relative to reference gene expression stabilities, nevertheless, PGK1 and GAPDH could serve as two possible common reference genes for qPCR data normalization as both were identified as stable genes in wounded and unwounded skin tissues. The differences of expression stabilities of the reference genes identified in both groups support the need for accurate normalization of gene-expression levels previous to qPCR studies.

Low Level Fluoride Stimulates Epithelial-Mesenchymal Interaction in Oral Mucosa

Oral mucosa consists of the superficial epithelium and the underlying lamina propria, and it functions as a barrier against exogenous substances. In development, interactions of stem/progenitor cells of the epithelium and mesenchyme are crucial to the morphogenesis of oral mucosa. Our previous work in low level fluorideinduced cell motility of epithelial cells has yielded important clues for periodontal physiology. This study focuses on a working concept of low level fluoride to provide a conducive oral environment for pivotal epithelialmesenchymal interactions. Cultured human primary gingival epithelial cells treated with 50 μM NaF were investigated by DNA microarray. Quantitative real-time PCR and an in vivo experimental rat skin wound model were employed to confirm the findings obtained with the microarray analysis. Microarray data revealed that low level fluoride-treated human gingival epithelial cells elevated various biological processes. The key proliferation markers, FGF2 and FGF7, and mesenchymal marker, Twist1, expression was up-regulated and quantitative real-time PCR confirmed this observation. Our in vivo study revealed that low concentration of NaF increased FGF2, FGF7, and Twist1 protein expression in fluoride-treated skin wound tissues compared with controls. These results provide new information on low level fluoride-induced epithelial-mesenchymal interactions and may thus aid in the understanding of oral mucosa development.

STUDY ON THE BACTERIA THAT CAUSE HOSPITAL INFECTIONS AT HUE CENTRAL HOSPITAL IN 2012

Objective: To study the bacterial etiologies causing hospital infections at Hue Central Hospital to determine the type of bacteria causing major hospital infections, distribution by local hospital infections, treatment areas contributing to control hospital infections. Subjects and methods: The study described on 311 bacteria strains that isolated in 242 patients who sufer hospital infections with 261 samples from 5/2011 to 5/2012. Results, discussion and conclusions: Hospital infections were 66.9% in male and 33.1%) in female patients, with 261 specimens we isolated 311 bacterial that cause hospital infections. - Respiratory tract infections were the highest rate (37.2%), followed by wound infection (20.2%) and the skin and soft tissue infections (13.2%), bloodstream infections (12,8%). - Five kinds of common infections were: respiratory infections, surgical wound infections, skin and soft tissue infections, urinary tract infections, blood infections. - Sputum is mainly specimens that accounted 35.2%, followed by 34.9% pus specimens, remaining is all kinds of other specimens. - Hospital infections due to Gram-negative bacteria 83.9% that was 5.2 times higher than that of Gram-positive bacterial (16.1%). - The bacterial etiologies causing hospital infections in Hue Central Hospital have five major types: the highest is Acinetobacter baumannii (27.3%), followed by Klebsiella pneumoniae (23.8%), Escherichia coli (15.8%), Staphylococcus aureus (10.6%), Pseudomonas aeruginosa (7.1%). - There are 43 specimens that were isolated two or more types of bacteria (16.5%).

Emu oil-based electrospun nanofibrous scaffolds for wound skin tissue engineering

Emu oil blended nanofibrous membranes scaffolds were fabricated successfully via electrospinning with different composition ratios with polyurethane (PU). Emu oil is derived from the emu (Dromaius novaehollandiae), which originated in Australia, and has been reported to have anti-inflammatory properties. It has been observed that 10wt.% is the optimum oil content in the electrospun solution to get good morphology ultrafine PU/emu oil blended nanofibers. The influences of emu oil content in nanofibrous morphology, and the viability and proliferation properties of cells (3T3-L1 fibroblasts) on blended nanofibers were analyzed. The composite material could support long-term cell growth, form three-dimensional networks of the nanofibrous structure, and provide good antibacterial activity. The antibacterial activity of this composite material was found to be active in both Gram positive and Gram negative species. So according to our results this composite material can be successfully applied in various biomedical fields, including wound dressing, skin disease treatments, etc.

A Retrospective Review of Iatrogenic Skin and Soft Tissue Injuries

BackgroundEven though the quality of medical and surgical care has improved remarkably over time, iatrogenic injuries that require surgical treatment including injuries caused by cast and elastic bandage pressure, extravasation, and dopamine-induced ischemia still frequently occur. The goal of this study was to estimate the incidence and analyze the distribution of iatrogenic injuries referred to our department.MethodsA retrospective clinical review was performed from April 2006 to November 2010. In total, 196 patients (116 females and 80 males) were referred to the plastic surgery department for the treatment of iatrogenic injuries. We analyzed the types and anatomic locations of iatrogenic complications, along with therapeutic results.ResultsAn extravasation injury (65 cases, 37.4%) was the most common iatrogenic complication in our study sample, followed by splint-induced skin ulceration, dopamine-induced necrosis, prefabricated pneumatic walking brace-related wounds and elastic bandage-induced wounds. Among these, prefabricated pneumatic walking brace-related complication incidence increased the most during the 5-year study period.ConclusionsThe awareness of the very common iatrogenic complications and its causes may allow physicians to reduce their occurrence and allow for earlier detection and referral to a plastic surgeon. We believe this is the first study to analyze iatrogenic complications referred to a plastic surgery department in a hospital unit.

Tolerance of High‐Intensity Focused Ultrasound Ablation in Patients with Hepatocellular Carcinoma

BackgroundHigh-intensity focused ultrasound (HIFU) ablation is a relatively new, noninvasive way of ablation for treating hepatocellular carcinoma (HCC). Emerging evidence has shown that it is effective for the treatment of HCC, even in patients with poor liver function. There is currently no data on the safety limit of HIFU ablation in patients with cirrhosis. However, this information is vital for the selection of appropriate patients for the procedure. We analyzed HCC patients who had undergone HIFU ablation and determined the lower limit of liver function and other patient factors with which HCC patients can tolerate this treatment modality.MethodsPreoperative variables of 100 patients who underwent HIFU ablation for HCC were analyzed to identify the risk factors in HIFU intolerance in terms of stress-induced complications. Factors that may contribute to postablation complications were compared.ResultsThirteen (13 %) patients developed a total of 18 complications. Morbidity was mainly due to skin and subcutaneous tissue injuries (n = 9). Five patients had first-degree skin burn, one had second-degree skin burn, and three had third-degree skin burn. Four complications were grade 3a in the Clavien classification and 14 were below this grade. Univariate analysis showed that age (p = 0.022) was the only independent factor in HIFU intolerance.ConclusionsHIFU ablation is generally well tolerated in HCC patients with cirrhosis. It is safe for Child-Pugh A and B patients and selected Child-Pugh C patients. With this new modality, HCC patients who were deemed unsalvageable by other surgical means in the past because of simultaneous Child-Pugh B or C disease now have a new hope.

Erythropoietin improves skin wound healing and activates the TGF-β signaling pathway

We could recently report that erythropoietin (EPO) accelerates skin wound healing in mice. Now, we provide insight into the molecular mechanisms of this non-hematopoietic property of EPO analyzing the transforming growth factor (TGF)-β signaling pathway. EPO receptor was found expressed in both non-wounded and wounded skin tissue as well as in fibroblasts and keratinocytes. In saline-treated control animals, wounds exhibited a significant upregulation of TGF-β1 and of α-smooth muscle actin (α-SMA) compared with non-wounded skin. EPO treatment accelerated wound epithelialization and induced mRNA expression of TGF-β1 and α-SMA. In addition, EPO significantly enhanced phosphorylation of Smad2 and Smad3 in fibroblasts and also elevated phosphorylation of Smad3 in wound tissue. Blockade of TGF-β using a neutralizing anti-TGF-β antibody attenuated EPO-induced acceleration of wound epithelialization in vivo and markedly reversed EPO effects on mRNA expression of TGF-β1 and α-SMA. In conclusion, EPO caused activation of the Smad-dependent TGF-β signaling pathway, enhanced differentiation of myofibroblasts, and accelerated skin wound closure.

Efficacy of chitin-PAA-GTMAC gel in promoting wound healing: animal study

Acrylic grafted chitin (chitin-PAA) was modified with glycidyltrimethylammonium chloride (GTMAC) with the aim of promoting wound healing. The chitin-PAA-GTMAC gels with different GTMAC contents were compared with the original chitin-PAA gel and Intrasite gel for their efficacy in deep wound healing of Wistar rats. Four full-thickness wounds were made on the dorsal skin of rats and then each was treated with 4 materials; chitin-PAA, chitin-PAA-GTMAC(1:4), chitin-PAA-GTMAC(1:10) and Intrasite gel. During 18 days of treatment, the wounds were visually observed and calculated for wound size using image analysis program. Skin wound tissues of sacrificed rats were processed for routine histological observation and immunohistochemistry of proliferating cell nuclear antigen (PCNA). The wounds covered with the chitin derivatives either with or without GTMAC showed a significant reduction in wound size in day 9 in comparison with day 12 for those covered with Intrasite gel. The faster rate and the better pattern of epidermal development observed in histological study as well as the higher dermal cell proliferation (PCNA expression) also demonstrated the better efficiency in wound healing of the chitin derivatives than Intrasite. The earliest epidermal development of the wounds treated with chitin-PAA-GTMAC (1:4) among the tested materials suggested the most promising of this material for the treatment of full-thickness open wound.

Effects of genistein on early-stage cutaneous wound healing

Wound healing occurs in three sequential phases: hemostasis and inflammation, proliferation, and remodeling. Inflammation, the earliest phase, is considered a critical period for wound healing because immune cells remove damaged tissues, foreign debris, and remaining dead tissue. Wound healing would be delayed without inflammation, and this phase is affected by antioxidation capacity. Therefore, we hypothesized that genistein, which has an antioxidant effect, might modulate the wound healing process by altering the inflammatory response. After three days of acclimation, mice were divided into three groups: control, 0.025% genistein, and 0.1% genistein. After two weeks of an experimental diet, skin wounds were induced. Wounded skin areas were imaged, and the healing rate calculated. To measure lipid peroxidation, antioxidant enzyme expression and activity, and pro-inflammatory cytokine expression, skin and liver tissues were harvested at 12, 24, 48, and 72 h. Genistein did not affect body weight. The rate of wound closure in mice fed genistein was significantly faster than in the control group during the early stage of wound healing, especially in first three days. Cu, Zn-SOD and Mn-SOD expression in wound skin tissue in the 0.1% genistein group was lower than in the control group. However, CAT expression did not differ among groups. We also found that genistein modulated NF-κB and TNF-α expression during the early stage of wound healing. The genistein group had significantly lower hepatic lipid peroxidation and higher SOD, CAT, and GPx activities than the control group. These results suggest that genistein supplementation reduces oxidative stress by increasing antioxidant capacity and modulating proinflammatory cytokine expression during the early stage of wound healing.

Use of gene-modified keratinocytes and fibroblasts to enhance regeneration in a full skin defect

With the development of cell-based gene transfer techniques, genetically modified human keratinocytes (Kc) and fibroblasts (Fb) have been proven to be a better choice in wound repair. This study was designed to construct in one step a gene-modified artificial skin by a genetically engineered Kc expressing PDGF-BB and Fb expressing VEGF(165) and bFGF. The wound healing effect in a full-thickness wound model was then observed. Unmodified artificial skin served as control. On the post-operative days7, 14, and 21, residual wound area was calculated and skin wound tissues were subjected to biopsy for further investigation. Compared with unmodified artificial skin, gene-modified artificial skin resulted in a reduced wound contraction and a well-organized human epidermis and better formed dermis. The results suggest that our two-layer, gene-modified artificial skin improved both vascularization and epidermalization for skin regeneration. This technique could bring about a new approach in the treatment of burns and chronic wounds.