Development of a histomorphologic scale to quantify cutaneous scars after burns

Smartphone-based optical palpation: towards elastography of skin for telehealth applications

Smartphones are now integral to many telehealth services that provide remote patients with an improved diagnostic standard of care. The ongoing management of burn wounds and scars is one area in which telehealth has been adopted, using video and photography to assess the repair process over time. However, a current limitation is the inability to evaluate scar stiffness objectively and repeatedly: an essential measurement for classifying the degree of inflammation and fibrosis. Optical elastography detects mechanical contrast on a micrometer- to millimeter-scale, however, typically requires expensive optics and bulky imaging systems, making it prohibitive for wide-spread adoption in telehealth. More recently, a new variant of optical elastography, camera-based optical palpation, has demonstrated the capability to perform elastography at low cost using a standard digital camera. In this paper, we propose smartphone-based optical palpation, adapting camera-based optical palpation by utilizing a commercially available smartphone camera to provide sub-millimeter resolution imaging of mechanical contrast in scar tissue in a form factor that is amenable to telehealth. We first validate this technique on a silicone phantom containing a 5 × 5 × 1 mm³ embedded inclusion, demonstrating comparative image quality between mounted and handheld implementations. We then demonstrate preliminary in vivo smartphone-based optical palpation by imaging a region of healthy skin and two scars on a burns patient, showing clear mechanical contrast between regions of scar tissue and healthy tissue. This study represents the first implementation of elastography on a smartphone device, extending the potential application of elastography to telehealth.

Impairment of wound healing by reactive skin decontamination lotion (RSDL®) in a Göttingen minipig® model

Reactive Skin Decontamination Lotion (RSDL^®) is an FDA-approved skin decontamination kit carried by service members for removal and neutralisation of vesicants and nerve agents. The RSDL kit, comprised of a lotion-impregnated sponge, was shown to be the superior medical decontamination device for chemical warfare agent (CWA) exposure on intact skin. In the event of a chemical exposure situation (i.e. terrorism, battlefield) physical injuries are probable, and preservation of life will outweigh the risk associated with application of RSDL to compromised skin. The purpose of this study was to quantify the rate and quality of wound healing in epidermal skin wounds treated with RSDL in a porcine model. Degree of wound healing was assessed using bioengineering methods to include ballistometry, colorimetry, evaporimetry, and high-frequency ultrasonography. Clinical observation, histopathology and immunohistochemistry were also utilised. All pigs received four bilateral superficial abdominal wounds via a pneumatic dermatome on their ventral abdomen, then were treated with the following dressings over a seven-day period: RSDL sponge, petroleum based Xeroform^® gauze, 3 M™ Tegaderm™ Film, and 3 M™ Tegaderm™ Foam. Two additional non-wounded sites on the flank were used as controls. Two groups of pigs were then evaluated for a 21- or 56-day time period, representing short- and long-term wound-healing progression. Our findings indicated RSDL had a negative impact on wound-healing progression at both 21 and 56 days post-injury. Wounds receiving RSDL demonstrated a decreased skin elasticity, significant transepidermal water loss, and altered skin colouration and thickness. In addition, the rate of wound healing was delayed, and return to a functional skin barrier was altered when compared to non-RSDL-treated wounds. In conclusion, wound management care and clinical therapeutic intervention plans should be established to account for a prolonged duration of healing in patients with RSDL-contaminated wounds.

In Vivo Evaluation of Three-Dimensional Printed, Keratin-Based Hydrogels in a Porcine Thermal Burn Model

Keratin is a natural material that can be derived from the cortex of human hair. Our group had previously presented a method for the printed, sequential production of three-dimensional (3D) keratin scaffolds. Using a riboflavin-sodium persulfate-hydroquinone (initiator-catalyst-inhibitor) photosensitive solution, we produced 3D keratin-based constructs through ultraviolet crosslinking in a lithography-based 3D printer. In this study, we have used this bioink to produce a keratin-based construct that is capable of delivering small molecules, providing an environment conducive to healing of dermal burn wounds in vivo, and maintaining stability in customized packaging. We characterized the effects of manufacturing steps, such as lyophilization and gamma irradiation sterilization on the properties of 3D printed keratin scaffolds prepared for in vivo testing. Keratin hydrogels are viable for the uptake and release of contracture-inhibiting Halofuginone, a collagen synthesis inhibitor that has been shown to decrease collagen synthesis in fibrosis cases. This small-molecule delivery provides a mechanism to reduce scarring of severe burn wounds in vitro. In vivo data show that the Halofuginone-laden printed keratin is noninferior to other similar approaches reported in literature. This is indicative that the use of 3D printed keratin is not inhibiting the healing processes, and the inclusion of Halofuginone induces a more organized dermal healing after a burn; in other words, this treatment is slower but improves healing. These studies are indicative of the potential of Halofuginone-laden keratin dressings in dermal wound healing. We aim to keep increasing the complexity of the 3D printed constructs toward the production of complex scaffolds for the treatment and topographical reconstruction of severe burn wounds to the face.

Epidermal stem cells in wound healing and their clinical applications

The skin has important barrier, sensory, and immune functions, contributing to the health and integrity of the organism. Extensive skin injuries that threaten the entire organism require immediate and effective treatment. Wound healing is a natural response, but in severe conditions, such as burns and diabetes, this process is insufficient to achieve effective treatment. Epidermal stem cells (EPSCs) are a multipotent cell type and are committed to the formation and differentiation of the functional epidermis. As the contributions of EPSCs in wound healing and tissue regeneration have been increasingly attracting the attention of researchers, a rising number of therapies based on EPSCs are currently under development. In this paper, we review the characteristics of EPSCs and the mechanisms underlying their functions during wound healing. Applications of EPSCs are also discussed to determine the potential and feasibility of using EPSCs clinically in wound healing.

Outcome of Beveled versus Vertical IncisionTechnique after Reconstructive or Aesthetic Facial Surgery

Background:

We suggest that the degree of scar improvement with a beveled incision technique with an angle of about 20 degrees to the skin can be translated for various reconstructions on the face and can be verified by a validated clinical assessment scale and histology.

Methods:

A total of 5 patients (2 men and 3 women) with a mean age of 68 years (range 54–84 years) undergoing elective surgeries on the face for tumor excision or cosmetic procedures were included. The beveled incision technique was compared with the conventional vertical incision (control group). Outcome measures were major and minor complications, pain and scar quality using the Patient and Observer Scar Assessment Scale, and histomorphologic scar assessment.

Results:

After a mean follow-up of 7.6 months (range 6–13 months), all patients healed uneventfully without pain, hypertrophic scars, or infection. We found a better overall Patient and Observer Scar Assessment Scale score in the beveled incision technique group (15 ± 3.4) compared with the conventional vertical incision group (18.4 ± 7.8, P = 0.7). Histomorphologic analyses showed after 6 months less scar zone, less inflammatory reaction, fewer macrophages, less foreign body reaction, and more hair follicles in the beveled incision technique group compared with the vertical incision group.

Conclusion:

We showed that the beveled incision technique using a 20-degree angle in elective surgeries on the face yields a cosmetic pleasant result for both the patient and the surgeon, which also goes in line with our histomorphologic analyses.

Allogeneic mesenchymal stem cells improve the wound healing process of sheep skin

BACKGROUND

Skin wound healing includes a system of biological processes, collectively restoring the integrity of the skin after injury. Healing by second intention refers to repair of large and deep wounds where the tissue edges cannot be approximated and substantial scarring is often observed. The objective of this study was to evaluate the effects of mesenchymal stem cells (MSCs) in second intention healing using a surgical wound model in sheep. MSCs are known to contribute to the inflammatory, proliferative, and remodeling phases of the skin regeneration process in rodent models, but data are lacking for large animal models. This study used three different approaches (clinical, histopathological, and molecular analysis) to assess the putative action of allogeneic MSCs at 15 and 42 days after lesion creation.

RESULTS

At 15 days post-lesion, the wounds treated with MSCs showed a higher degree of wound closure, a higher percentage of re-epithelialization, proliferation, neovascularization and increased contraction in comparison to a control group. At 42 days, the wounds treated with MSCs had more mature and denser cutaneous adnexa compared to the control group. The MSCs-treated group showed an absence of inflammation and expression of CD3+ and CD20+. Moreover, the mRNA expression of hair-keratine (hKER) was observed in the MSCs-treated group 15 days after wound creation and had increased significantly by 42 days post-wound creation. Collagen1 gene (Col1α1) expression was also greater in the MSCs-treated group compared to the control group at both days 15 and 42.

CONCLUSION

Peripheral blood-derived MSCs may improve the quality of wound healing both for superficial injuries and deep lesions. MSCs did not induce an inflammatory response and accelerated the appearance of granulation tissue, neovascularization, structural proteins, and skin adnexa.

Advances of Stem Cell Therapeutics in Cutaneous Wound Healing and Regeneration

Cutaneous wound healing is a complex multiple phase process, which overlaps each other, where several growth factors, cytokines, chemokines, and various cells interact in a well-orchestrated manner. However, an imbalance in any of these phases and factors may lead to disruption in harmony of normal wound healing process, resulting in transformation towards chronic nonhealing wounds and abnormal scar formation. Although various therapeutic interventions are available to treat chronic wounds, current wound-care has met with limited success. Progenitor stem cells possess potential therapeutic ability to overcome limitations of the present treatments as it offers accelerated wound repair with tissue regeneration. A substantial number of stem cell therapies for cutaneous wounds are currently under development as a result of encouraging preliminary findings in both preclinical and clinical studies. However, the mechanisms by which these stem cells contribute to the healing process have yet to be elucidated. In this review, we emphasize on the major treatment modalities currently available for the treatment of the wound, role of various interstitial stem cells and exogenous adult stem cells in cutaneous wound healing, and possible mechanisms involved in the healing process.

Transplanted Mesenchymal Stem Cells Are Effective for Skin Regeneration in Acute Cutaneous Wounds

Mesenchymal stem cells (MSCs) possess the capacity for site-specific differentiation of cell types in response to cues provided by different organs. This phenomenon suggests that MSCs participate in cutaneous wound regeneration. However, there are no prior reports on the influence of the local application of MSCs on cutaneous wound regeneration. To examine the effects of MSCs on wound regeneration, we cultured bone marrow cells of the femur of rats and treated the plastic adherent cells with a differentiation medium to induce differentiation. After treatment, we found that the bone marrow-derived plastic adherent cells possessed myogenesis, chondrogenesis, and adipogenesis capabilities, indicating that these cells are MSCs. The bone marrow-derived plastic adherent cells were injected intradermally into the skin of rats, and linear full-thickness incisional wounds were made immediately through the injected area. At 14 days after operation, wounds transplanted with bone marrow-derived plastic adherent cells had healed with very fine scars. Collagen architecture was thick and appeared to be similar to normal dermis. Histomorphologic scale analysis demonstrated significant differences between the control and the wounds transplanted with bone marrow-derived plastic adherent cells. These results indicate that transplanted MSCs can respond quite normally to wound healing and regenerate dermal structure.

A systematic review of objective burn scar measurements

BACKGROUND

Problematic scarring remains a challenging aspect to address in the treatment of burns and can significantly affect the quality of life of the burn survivor. At present, there are few treatments available in the clinic to control adverse scarring, but experimental pharmacological anti-scarring strategies are now beginning to emerge. Their comparative success must be based on objective measurements of scarring, yet currently the clinical assessment of scars is not carried out systematically and is mostly based on subjective review of patients. However, several techniques and devices are being introduced that allow objective analysis of the burn scar. The aim of this article is to evaluate various objective measurement tools currently available and recommend a useful panel that is suitable for use in clinical trials of anti-scarring therapies.

METHODS

A systematic literature search was done using the Web of Science, PubMed and Cochrane databases. The identified devices were then classified and grouped according to the parameters they measured. The tools were then compared and assessed in terms of inter- and intra-rater reproducibility, ease of use and cost.

RESULTS

After duplicates were removed, 5062 articles were obtained in the search. After further screening, 157 articles which utilised objective burn scar measurement systems or tools were obtained. The scar measurement devices can be broadly classified into those measuring colour, metric variables, texture, biomechanical properties and pathophysiological disturbances.

CONCLUSIONS

Objective scar measurement tools allow the accurate and reproducible evaluation of scars, which is important for both clinical and scientific use. However, studies to evaluate their relative performance and merits of these tools are scarce, and there remain factors, such as itch and pain, which cannot be measured objectively. On reviewing the available evidence, a panel of devices for objective scar measurement is recommended consisting of the 3D cameras (Eykona/Lifeviz/Vectra H1) for surface area and volume, DSM II colorimeter for colour, Dermascan high-frequency ultrasound for scar thickness and Cutometer for skin elasticity and pliability.

Human Wharton's Jelly Mesenchymal Stem Cells plasticity augments scar-free skin wound healing with hair growth

Human mesenchymal stem cells (MSCs) are a promising candidate for cell-based transplantation and regenerative medicine therapies. Thus in the present study Wharton's Jelly Mesenchymal Stem Cells (WJ-MSCs) have been derived from extra embryonic umbilical cord matrix following removal of both arteries and vein. Also, to overcome the clinical limitations posed by fetal bovine serum (FBS) supplementation because of xenogeneic origin of FBS, usual FBS cell culture supplement has been replaced with human platelet lysate (HPL). Apart from general characteristic features of bone marrow-derived MSCs, wharton jelly-derived MSCs have the ability to maintain phenotypic attributes, cell growth kinetics, cell cycle pattern, in vitro multilineage differentiation plasticity, apoptotic pattern, normal karyotype-like intrinsic mesenchymal stem cell properties in long-term in vitro cultures. Moreover, the WJ-MSCs exhibited the in vitro multilineage differentiation capacity by giving rise to differentiated cells of not only mesodermal lineage but also to the cells of ectodermal and endodermal lineage. Also, WJ-MSC did not present any aberrant cell state upon in vivo transplantation in SCID mice and in vitro soft agar assays. The immunomodulatory potential assessed by gene expression levels of immunomodulatory factors upon exposure to inflammatory cytokines in the fetal WJ-MSCs was relatively higher compared to adult bone marrow-derived MSCs. WJ-MSCs seeded on decellularized amniotic membrane scaffold transplantation on the skin injury of SCID mice model demonstrates that combination of WJ-MSCs and decellularized amniotic membrane scaffold exhibited significantly better wound-healing capabilities, having reduced scar formation with hair growth and improved biomechanical properties of regenerated skin compared to WJ-MSCs alone. Further, our experimental data indicate that indocyanin green (ICG) at optimal concentration can be resourcefully used for labeling of stem cells and in vivo tracking by near infrared fluorescence non-invasive live cell imaging of labelled transplanted cells, thus proving its utility for therapeutic applications.

Multiparametric and semiquantitative scoring systems for the evaluation of mouse model histopathology--a systematic review

BACKGROUND

Histopathology has initially been and is still used to diagnose infectious, degenerative or neoplastic diseases in humans or animals. In addition to qualitative diagnoses semiquantitative scoring of a lesion`s magnitude on an ordinal scale is a commonly demanded task for histopathologists. Multiparametric, semiquantitative scoring systems for mouse models histopathology are a common approach to handle these questions and to include histopathologic information in biomedical research.

RESULTS

Inclusion criteria for scoring systems were a first description of a multiparametric, semiquantiative scoring systems which comprehensibly describe an approach to evaluate morphologic lesion. A comprehensive literature search using these criteria identified 153 originally designed semiquantitative scoring systems for the analysis of morphologic changes in mouse models covering almost all organs systems and a wide variety of disease models. Of these, colitis, experimental autoimmune encephalitis, lupus nephritis and collagen induced osteoarthritis colitis were the disease models with the largest number of different scoring systems. Closer analysis of the identified scoring systems revealed a lack of a rationale for the selection of the scoring parameters or a correlation between scoring parameter value and the magnitude of the clinical symptoms in most studies.

CONCLUSION

Although a decision for a particular scoring system is clearly dependent on the respective scientific question this review gives an overview on currently available systems and may therefore allow for a better choice for the respective project.

The role of disgust emotions in the observer response to facial disfigurement

Social intrusions by observers are commonly reported by those with disfiguring conditions. This study examined the role of disgust emotions in the observer response. A group of students (N=48) completed quantitative questionnaires measuring extent of disfigurement, whilst viewing images of faces with varying disfigurements. Another group of students (N=84) completed quantitative questionnaires measuring level of disgust elicited by the same images. Disgust sensitivity was measured using the Disgust Scale Revised. Observers reported greater levels of disgust (p<.01) with increasing severity of facial disfigurement. Individuals with a higher disgust sensitivity reported increased levels of disgust in response to faces of mild (p=.03), moderate (p=.02) and severe (p<.01) disfigurement compared to those with a lower disgust sensitivity. This provides an explanatory framework for the avoidance reactions of observers and may be important in understanding variability in adjustment following disfigurement.

Enhanced cryoprecipitate for skin graft and donor site wound healing in pigs

Due to similarities in skin characteristics, the authors hypothesise that a pig model would most accurately show the ability of autologous, enhanced cryoprecipitate (eCryo) to improve the wound healing of split-thickness skin grafts (STSGs) and corresponding donor sites. Fifty-two STSGs (5 × 5 cm) were fashioned and treated according to a randomised protocol with an autologous eCryo-treated and a control group. Macroscopic assessment, histological evaluation and cellular composition were completed at days 7, 14, 21 and 28. Thirty-two donor sites were also created and assessed in a similar manner. Histologic analysis showed enhancement of healing over all time points for eCryo-treated donor sites. All other results showed no statistically significant improvement with the use of eCryo. Autologous cryoprecipitate appears to be a safe, inexpensive and easy-to-use alternative to fibrin glue, which carries risks and is, in many cases, prohibitively expensive. Further studies are necessary to evaluate the full potential of eCryo. Interestingly, eCryo application may improve donor site aesthetic appearance. We believe that a pig model most reliably simulates eCryo's behaviour in humans to accurately reflect its future clinical applicability.

Using stem cells in skin regeneration: possibilities and reality

Tissue-engineered skin has a long history of clinical applications, yet current treatments are not capable of completely regenerating normal, uninjured skin. Nonetheless, the field has experienced a tremendous development in the past 10 years, encountering the summit of tissue engineering (TE) and the arising of stem cell research. Since then, unique features of these cells such as self-renewal capacity, multi-lineage differentiation potential, and wound healing properties have been highlighted. However, a realistic perspective of their outcome in skin regenerative medicine applications is still absent. This review intends to discuss the directions that adult and embryonic stem cells (ESCs) can take, strengthening the skin regeneration field. Distinctively, a critical overview of stem cells' differentiation potential onto skin main lineages, along with a highlight of their participation in wound healing mechanisms, is herein provided. We aim to compile and review significant work to allow a better understanding of the best skin TE approaches, enabling the embodiment of the materialization of a new era in skin regeneration to come, with a conscious overview of the current limitations.

A systematic review of the quality of burn scar rating scales for clinical and research use

INTRODUCTION

Scar rating scales have the potential to contribute to better evaluation of scar properties in both research and clinical settings. Despite a large number of scars assessment scales being available, there is limited information regarding the clinimetric properties of many of these scales. The purpose of the review was to inform clinical and research practice by determining the quality and appropriateness of existing scales. This review summarises the available evidence for the clinimetric properties of reliability, validity (including responsiveness), interpretability and feasibility of existing scales.

METHODS

Electronic searches of MEDLINE, CINAHL, EMBASE and The Cochrane Library databases from 1990 onwards were used to identify English articles related to burn scar assessment scales. Scales were critically reviewed for clinimetric properties that were reported in, but not necessarily the focus of studies.

RESULTS

A total of 29 studies provided data for 18 different scar rating scales. Most scar rating scales assessed vascularity, pliability, height and thickness. Some scales contained additional items such as itch. Only the Patient and Observer Scar Assessment Scale (POSAS) received a high quality rating but only in the area of reliability for total scores and the subscale vascularity. The Vancouver Scar Scale (VSS) received indeterminate ratings for construct validity, reliability and responsiveness. Where evidence was available, all other criteria for the POSAS, VSS and the remaining 17 scales received an indeterminate rating due to methodological issues, or a low quality rating. Poorly defined hypotheses limited the ability to give a high quality rating to data pertaining to construct validity, responsiveness and interpretability. No scale had empirical testing of content validity and no scale was of sufficient quality to consider criterion validity.

CONCLUSIONS

The POSAS, with high quality reliability but indeterminate validity, was considered to be superior in performance based on existing evidence. The VSS had the most thorough review of clnimetrics although available data received indeterminate quality ratings. On the basis of the evidence, the use of total scores has not been supported, nor has the measurement of pigmentation using a categorical scale.

Comparison between topical honey and mafenide acetate in treatment of auricular burn

The auricle is a frequently injured part of the head and neck during thermal injury leading to ear deformity. The burned ear represents one of the most difficult problems for reconstructive surgeons. Mafenide acetate is a topical agent used routinely for these patients, but it has some disadvantages including painful application and allergic rash. Some authors have reported the healing effect and antibacterial activity of honey. The study reported here was undertaken to compare the effect of honey and mafenide acetate on auricular burn in rabbit. In our study, although the pathologic score of the honey group was better than that of the mafenide group both on 14 and 21 days after burning, it was not statistically significant. In the mafenide acetate group, deep complication of burn (chondritis) was significantly lower than that of the honey group. In conclusion, in contrast to healing and antibiotic activity reported for honey, it may have failure in preventing deep bacterial complications of wound (like chondritis). So in deep wounds, the use of honey as dressing is not recommended.

Role of transforming growth factor Beta in corneal function, biology and pathology

Transforming growth factor-beta (TGFbeta) is a pleiotropic multifunctional cytokine that regulates several essential cellular processes in many parts of the body including the cornea. Three isoforms of TGFbeta are known in mammals and the human cornea expresses all of them. TGFbeta1 has been shown to play a central role in scar formation in adult corneas whereas TGFbeta2 and TGFbeta3 have been implicated to play a critical role in corneal development and scarless wound healing during embryogenesis. The biological effects of TGFbeta in the cornea have been shown to follow Smad dependent as well as Smad-independent signaling pathways depending upon cellular responses and microenvironment. Corneal TGFbeta expression is necessary for maintaining corneal integrity and corneal wound healing. On the other hand, TGFbeta is perhaps the most important cytokine in the pathogenesis of fibrotic disease in the cornea. Although the transformation of keratocytes to myofibroblasts induced by TGFbeta is largely believed to cause corneal fibrosis or scarring, the precise molecular mechanism(s) involved in this process is still unknown. Currently no drugs are available to treat corneal scarring effectively without causing significant side effects. Many approaches to treat TGFbeta-mediated corneal scarring are under investigation. These include blocking of TGFbeta, TGFbeta receptor, TGFbeta function and/or TGFbeta maturation. Other strategies such as modulating keratocyte proliferation, apoptosis, transcription and DNA condensation are also being investigated. The potential of gene therapy to neutralize the pathologic effects of TGFbeta has also been demonstrated recently.

Exploring the role of stem cells in cutaneous wound healing

The skin offers a perfect model system for studying the wound healing cascade, which involves a finely tuned interplay between several cell types, pathways and processes. The dysregulation of these factors may lead to wound healing disorders resulting in chronic wounds, as well as abnormal scars such as hypertrophic and keloid scars. As the contribution of stem cells towards tissue regeneration and wound healing is increasingly appreciated, a rising number of stem cell therapies for cutaneous wounds are currently under development, encouraged by emerging preliminary findings in both animal models and human studies. However, we still lack an in-depth understanding of the underlying mechanisms through which stem cells contribute to cutaneous wound healing. The aim of this review is, therefore, to present a critical synthesis of our current understanding of the role of stem cells in normal cutaneous wound healing. In addition to summarizing wound healing principles and related key molecular and cellular players, we discuss the potential participation of different cutaneous stem cell populations in wound healing, and list corresponding stem cells markers. In summary, this review delineates current strategies, future applications, and limitations of stem cell-based or stem cell-targeted therapy in the management of acute and chronic skin wounds.

A novel TGF-beta antagonist speeds reepithelialization and reduces scarring of partial thickness porcine burns

Scar formation after thermal injury is common and results in significant aesthetic and functional impairment. Transforming growth factor beta (TGF-beta) plays a significant role in scar formation. We tested the hypothesis that a novel TGF-beta peptantagonist would reduce scar formation and wound contraction in partial thickness burns by using a randomized controlled experiment. The subjects include two domestic pigs (20-25 kg). Forty burns were created on the animal's dorsum using an aluminum bar preheated to 80 degrees C and applied for 20 seconds resulting in a partial thickness thermal burn extending half way down the dermis. Burns were treated every other day for 1 week, then twice weekly for 3 weeks with a topical TGF-beta antagonist or its vehicle. Full thickness biopsies were obtained from all burns at 7, 10, and 14 days after injury. The wounds were completely excised after 28 days for histological assessment. Wound sections were stained with H&&E and evaluated by a dermatopathologist masked to treatment assignment for reepithelialization and depth of scar formation. We also determined the number of wounds at 28 days that healed with contracted, hour-glass shaped scars. Data were compared with chi and t-tests. Twenty burns were treated with TGF-beta antagonist and 20 with control vehicle. TGF-beta antagonist increased the percentage of completely reepithelialized wounds at 14 days (90 vs 45%, P = .002) and reduced the percentage of contracted wounds (35 vs 65%, P = .02) and full thickness scars (10 vs 60%, P = .002) at 28 days. Treatment of partial thickness porcine burns with the TGF-beta antagonist speeds reepithelialization and reduces scar formation and wound contraction in partial thickness porcine burns.

Novel cryoprecipitate for wound healing and skin grafts in rats

The authors sought to evaluate the ability of locally administered enhanced cryoprecipitate (eCryo) to improve the wound healing of split thickness skin grafts (STSG) and their donor sites. An STSG (5 x 5 cm) was harvested on the back of 30 rats and divided into four areas that were then treated in one of the following groups: A: 'standard' dressing without STSG; B: eCryo without STSG; C: eCryo with STSG coverage and D: STSG alone. Macroscopic and histological assessments (histomorphometric grading scale and cellular composition) were evaluated at days 7, 14, 21 and 28 for wound healing. All wound beds as well as STSGs healed well without any complications. Eighty per cent of the STSG showed a histological graft take of >75% after 28 days. There were no statistically significant differences of macroscopic or histological results between the groups at any time point. Preparation of eCryo is easy and effective. Its use as an adhesive for STSGs is safe and shows similar results as controls. The theoretical benefits of eCryo did not show significant differences. Possible reasons as well as important findings for future research on wound healing are discussed.

Promotion of incisional wound repair by human mesenchymal stem cell transplantation

The purpose of this study was to determine the effect of transplanted human mesenchymal stem cells (hMSCs) on wound healing. In this model, full-thickness cutaneous wounds were created by incision in the skin of adult New Zealand white rabbits and treated by transplanted hMSCs into the wounds. Wound healing was evaluated by histological analysis and tensiometry over time. A total of 15 New Zealand white rabbits with 10 wounds per animal were examined in this study. Animals were treated with hMSCs and euthanised at 3, 7, 14, 21 and 80 days after manipulation. The hMSCs were labelled with a fluorescent dye (CM-DiI), suspended in phosphate-buffered saline and used to treat full-thickness incisional wounds in rabbit skin. Tensiometry and histology were used to characterise the wound-healing rate of the incisional wounds. These results showed that transplanted hMSCs significantly inhibited scar formation and increased the tensile strength of the wounds. Importantly, MSCs from genetically unrelated donors did not appear to induce an immunologic response. In conclusion, human mesenchymal stem cell therapy is a viable approach to significantly affect the course of normal cutaneous wound healing and significantly increase the tensile strength.

A porcine model of full-thickness burn, excision and skin autografting

Acute burn wounds often require early excision and adequate coverage to prevent further hypothermia, protein and fluid losses, and the risk of infection. Meshed autologous skin grafts are generally regarded as the standard treatment for extensive full-thickness burns. Graft take and rate of wound healing, however, depend on several endogenous factors. This paper describes a standardized reproducible porcine model of burn and skin grafting which can be used to study the effects of topical treatments on graft take and re-epithelialization. Procedures provide a protocol for successful porcine burn wound experiments with special focus on pre-operative care, anesthesia, burn allocation, excision and grafting, postoperative treatment, dressing application, and specimen collection. Selected outcome measurements include percent area of wound closure by planimetry, wound assessment using a clinical assessment scale, and histological scoring. The use of this standardized model provides burn researchers with a valuable tool for the comparison of different topical drug treatments and dressing materials in a setting that closely mimics clinical reality.

The Effect of Topical Mitomycin C on Full-Thickness Burns

BACKGROUND

Burns result in substantial morbidity because of fibroblast proliferation and contracture. Mitomycin C is a chemotherapeutic agent known to suppress fibroblast proliferation. It is used in ophthalmologic disorders and reduces scarring in upper aerodigestive surgery. No study of the effect of mitomycin C on cutaneous burns has been performed. This study examined burn healing in the presence of topical mitomycin C by evaluation of wound appearance, contraction, and histology in a pig model.

METHODS

Standardized full-thickness burns were produced on the flanks of three pigs. One animal received no further therapy and was an external control. Two animals underwent placement of topical mitomycin C, 0.4 mg/ml, on selected burn sites for 5 minutes. This was repeated 2 and 4 weeks after injury. Evaluation was performed at 2 and 6 months using a clinical assessment scale and a visual analogue scale. Scar length and histologic analysis were also evaluated.

RESULTS

Clinical assessment scale and visual analogue scale scores showed improved appearance in the untreated external control wounds versus the untreated internal control and treated wounds (p < 0.001). Wound contraction was not significantly different between groups. Histologic characteristics between groups were similar except for epidermal hyperplasia, which was decreased in the untreated external control (p < 0.05) at 2 months after treatment.

CONCLUSIONS

Topical mitomycin C treatment of full-thickness burn wounds at 0.4 mg/cc for three courses does not improve, and may worsen, clinical appearance and scarring during early healing. There is no difference in histology during the long-term healing process. Scar contraction was unchanged.

Hair follicle stem cells: walking the maze

The discovery of epithelial stem cells (eSCs) in the bulge region of the outer root sheath of hair follicles in mice and man has encouraged research into utilizing the hair follicle as a therapeutic source of stem cells (SCs) for regenerative medicine, and has called attention to the hair follicle as a highly instructive model system for SC biology. Under physiological circumstances, bulge eSCs serve as cell pool for the cyclic regeneration of the anagen hair bulb, while they can also regenerate the sebaceous gland and the epidermis after injury. More recently, melanocyte SCs, nestin+, mesenchymal and additional, as yet ill-defined "stem cell" populations, have also been identified in or immediately adjacent to the hair follicle epithelium, including in the specialized hair follicle mesenchyme (connective tissue sheath), which is crucial to wound healing. Thus the hair follicle and its adjacent tissue environment contain unipotent, multipotent, and possibly even pluripotent SC populations of different developmental origin. It provides an ideal model system for the study of central issues in SC biology such as plasticity and SC niches, and for the identification of reliable, specific SC markers, which distinguish them from their immediate progeny (e.g. transient amplifying cells). The current review attempts to provide some guidance in this growing maze of hair follicle-associated SCs and their progeny, critically reviews potential or claimed hair follicle SC markers, highlights related differences between murine and human hair follicles, and defines major unanswered questions in this rapidly advancing field.

Effect of adenoviral mediated overexpression of fibromodulin on human dermal fibroblasts and scar formation in full-thickness incisional wounds

Fibromodulin, a member of the small leucine-rich proteoglycan family, has been recently suggested as a biologically significant mediator of fetal scarless repair. To assess the role of fibromodulin in the tissue remodeling, we constructed an adenoviral vector expressing human fibromodulin cDNA. We evaluated the effect of adenovirus-mediated overexpression of fibromodulin in vitro on transforming growth factors and metalloproteinases in fibroblasts and in vivo on full-thickness incisional wounds in a rabbit model. In vitro, we found that Ad-Fibromodulin induced a decrease of expression of TGF-beta(1) and TGF-beta(2) precursor proteins, but an increase in expression of TGF-beta(3) precursor protein and TGF-beta type II receptor. In addition, fibromodulin overexpression resulted in decreased MMP-1 and MMP-3 protein secretion but increased MMP-2, TIMP-1, and TIMP-2 secretion, whereas MMP-9 and MMP-13 were not influenced by fibromodulin overexpression. In vivo evaluation by histopathology and tensile strength demonstrated that Ad-Fibromodulin administration could ameliorate wound healing in incisional wounds. In conclusion, although the mechanism of scar formation in adult wounds remains incompletely understood, we found that fibromodulin overexpression improves wound healing in vivo, suggesting that fibromodulin may be a key mediator in reduced scarring.

A porcine deep dermal partial thickness burn model with hypertrophic scarring

We developed a reproducible model of deep dermal partial thickness burn injury in juvenile Large White pigs. The contact burn is created using water at 92 degrees C for 15s in a bottle with the bottom replaced with plastic wrap. The depth of injury was determined by a histopathologist who examined tissue sections 2 and 6 days after injury in a blinded manner. Upon creation, the circular wound area developed white eschar and a hyperaemic zone around the wound border. Animals were kept for 6 weeks or 99 days to examine the wound healing process. The wounds took between 3 and 5 weeks for complete re-epithelialisation. Most wounds developed contracted, purple, hypertrophic scars. On measurement, the thickness of the burned skin was approximately 1.8 times that of the control skin at week 6 and approximately 2.2 times thicker than control skin at 99 days after injury. We have developed various methods to assess healing wounds, including digital photographic analysis, depth of organising granulation tissue, immunohistochemistry, electron microscopy and tensiometry. Immunohistochemistry and electron microscopy showed that our porcine hypertrophic scar appears similar to human hypertrophic scarring. The development of this model allows us to test and compare different treatments on burn wounds.

Characterization strategies for the functional assessment of the cutaneous lesion

Assessment of wound healing is a complex task, especially when the lesion is associated to significant (full thickness) loss of the skin. The clinical observation, essentially subjective and highly dependent on the observer's experience, creates difficulties in the comparison of results. Scoring scales were introduced in the clinical practice to create comparable semi-quantitative data and promote better management of resources, but its usefulness in a clinical perspective is still limited. New non-invasive biometric methodologies, although infrequently used, have opened new possibilities. While complementing the clinical observation and contributing to therapeutic decisions and prognosis, they may also help to look further into the pathophysiological mechanisms of scarring drugs rehabilitation. Following previous work in this arena, the authors review, the state-of-the-art of cutaneous wound healing clinical and biometric follow up, proposing a diagnosis correlation for the most relevant descriptors found in both strategies in order to fully characterise the different stages of the healing process.

Quantifying collagen type in mature burn scars: a novel approach using histology and digital image analysis

Using Herovici staining and digital image analysis, we have studied the collagen subtype and fiber orientation in mature burn scars. These techniques have shown mature burn scars to have increased type I/type III collagen ratios compared with normal skin. Additionally, the collagen orientation of burn scars has been shown to be thickened, tightly packed, and lacking the "basket weave" appearance of normal skin specimens. These techniques allow the differentiation of type I collagen from type III collagen, the assessment of collagen orientation, and the analysis of scar architecture in terms of epidermis and papillary/reticular dermis contribution. These findings are important clinically because collagen subtype and fiber orientation may predict future scar activity. Any attempt to modify the scarring process can be directly measured and compared using this easily reproducible technique.

Semapimod Reduces the Depth of Injury Resulting in Enhanced Re-epithelialization of Partial-Thickness Burns in Swine

Studies suggest that tumor necrosis factor alpha (TNF-alpha) plays a role in burn pathogenesis. We conducted a randomized controlled experiment in swine to determine whether a novel macrophage inhibitor, semapimod (formerly known as CNI-1493), would blunt the local production of TNF-alpha, interleukin (IL)-1, and IL-6 in burns leading to less injury extension and faster re-epithelialization. After creating second-degree burns, animals received one or two intravenous boluses of semapimod 1 mg/kg or normal saline, and all burns were treated with silver sulfadiazine. The depth of follicular necrosis and thrombosis was reduced by either one or two doses of semapimod (P=.04 and .02, respectively). However, no differences were noted between groups in cytokine levels. Depth of scarring was similar in all groups. We conclude that Semapimod reduces the depth of follicular necrosis and thrombosis after second-degree burns in swine, indirectly resulting in more rapid re-epithelialization. However, this affect does not appear to be mediated by reduced local TNF-alpha, IL-1, or IL-6 protein levels.

Statistical analysis of wound-healing rates for pressure ulcers

To establish a functional model for determining wound-healing rates to use in the evaluation of efficacy of wound therapies, a review was conducted of statistical analysis methods from past wound-healing studies. Because most wounds do not usually close within the period of observation, that is, 12 weeks, evaluating time to 100% closure is not practical. Thus, a new, practical model for statistical analysis was formulated. A Gompertz-like function was applied to wound-healing rates of pressure ulcers, in the context of repeated measures for a nonlinear model. Photographing the wounds weekly, tracing their area with planimetry, and applying this new statistical model allows for the calculation of the expected rate of healing as a function of time. This approach yields a model useful for identifying prognostic factors, evaluating treatments, and improving our understanding of the variables that affect the wound-healing process.

The Effects of the Plasminogen Pathway on Scar Tissue Formation

OBJECTIVES/HYPOTHESIS

The authors sought to determine the role of the plasminogen pathway in wound healing. They hypothesized that decreased fibrin degradation may lead to increased collagen deposition. Presuming that the degree of histopathological abnormality correlates with the aesthetic appearance of the scar, we conducted a study that attempted to determine the histopathological appearance of scar tissue in mice with and without impaired function of the plasminogen pathway.

STUDY DESIGN

Mice with and without deficiencies in the plasminogen pathway underwent surgery. The role of the plasminogen pathway in wound healing was studied by analysis of scar tissue formation using the methods described.

METHODS

A 2-cm incision was made on the dorsum of mice with and without specified genetic deficiencies in the plasminogen pathway. After the animals were killed, the tissue was harvested, fixed, and prepared using hematoxylin and eosin as well as trichrome stains. Histopathological analysis and scoring were performed by two separate investigators in a blinded manner. Student's t test was used to determine statistical significance between groups.

RESULTS

A statistically significant difference in collagen orientation was noted between mice with impaired plasminogen pathway function and the wild-type (control) group (P =.0163). A statistical trend toward improved wound healing for plasminogen-deficient mice was found for overall histomorphological score (P =.0706).

CONCLUSION

The role of the plasminogen pathway in wound healing is one that should be noted and may lead to the development of new therapies that reduce scar tissue formation. Hence, the role of other thrombolytic and anti-thrombolytic agents in wound healing should be further investigated to precisely identify agents that play the most significant role in scar tissue formation.

Evaluation of a new liquid occlusive dressing for excisional wounds

We evaluated a novel octylcyanoacrylate-based liquid occlusive dressing for partial-thickness wounds. One hundred and fifteen standardized wounds were created with an electric dermatome set at a depth of 600 micro on the flanks of three pigs and randomly treated with liquid occlusive dressing, a hydrocolloid dressing, or gauze. In one pig, wounds were swabbed with Staphylococcus aureus. Biopsies were taken after 4, 5, 6, and 21 days. Hemostasis was obtained in all wounds treated with the liquid occlusive. The percent reepithelialization of wounds treated with the liquid occlusive and hydrocolloid dressings were significantly greater at days 4 and 5 than control wounds (78% and 82% vs. 40%, p < 0.001 and 99% and 100% vs. 72%, p < 0.001, respectively). None of the liquid occlusive-treated wounds challenged with bacteria became infected. Foreign body reactions were least common in wounds treated with the liquid occlusive (p < 0.001). Scar depth was less for liquid occlusive- and hydrocolloid-treated wounds than controls (285 micro and 303 micro vs. 490 micro, p < 0.001). We conclude that excisional wounds treated with the liquid occlusive dressing reepithelialize as quickly as hydrocolloid-treated wounds. The liquid occlusive dressing is an effective microbial barrier and hemostatic agent resulting in fewer foreign body reactions than hydrocolloid-treated wounds or controls.

Facial disfigurement: is it in the eye of the beholder? A study in patients with Graves' ophthalmopathy

OBJECTIVES

The importance of facial disfigurement in many diseases necessitates a reliable and valid measure of disfigurement severity for clinical studies. The hypothesis is that a universal concept of disfigurement exists and can be measured in a reliable way. The objectives of this study were to investigate if persons, in particular patients and physicians, can agree on facial disfigurement severity; and to determine the relative contribution of predefined clinical characteristics of patients with Graves' ophthalmopathy (GO) to the overall rating of facial disfigurement severity.

DESIGN

A panel study was carried out in four different panels, each consisting of four members.

PATIENTS

We randomly selected 100 slide pairs of GO patients from four available study populations, involving mild, moderate and severe GO patients (mean age 49 years, 76% female) who were treated with either radiotherapy, sham-irradiation, prednisone or orbital decompression.

MEASUREMENTS

All panel members individually scored the disfigurement severity of 100 GO patients shown on standardized slides on a Visual Analog Scale. In total, 1600 ratings were collected. We calculated within- and between-panel agreement of disfigurement severity and identified determinants of disfigurement.

RESULTS

Agreement within a panel varied from 0.65 to 0.79 and was highest within the panel of ophthalmologists. Between-panel agreement was 0.67 and was highest between ophthalmologists and laypersons. Compared with the global average, patients overrated and endocrinologists underrated disfigurement severity. Female panellists rated the patients, on average, more disfigured than male panellists. Important determinants of disfigurement were eyelid retraction, severe eyelid swelling and proptosis. Their relative importance was consistent across panels and in contrast to current measures of GO severity.

CONCLUSION

Facial disfigurement severity can be measured in a reliable way using panels of panellists. Except for some systematic differences between panellists, facial disfigurement does not seem to be in the eye of the beholder.

Persistent wound infection delays epidermal maturation and increases scarring in thermal burns

We developed a reliable scale measuring epidermal maturation during wound healing and determined the effects of persistent infection on epidermal maturation and dermal scarring after cutaneous burns. A secondary analysis of data from 80 contaminated burns collected during a randomized experiment comparing four topical burn therapies in a contaminated porcine burn model was performed. Persistent infection was defined histologically as the presence of intradermal neutrophils containing bacteria at 14 days. Epidermal maturation at 14 days was classified into one of five categories from least (0) to most (4) mature using strictly defined criteria. Dermal scarring was classified as none, superficial, or deep. The epidermal classification system was highly reliable (rho = 0.97). At 14 days, 18% of burns were infected. Most infected wounds (79%) had an immature epidermis (types 0-2) while most noninfected wounds (75%) had a mature epidermis (types 3 or 4); chi2 and chi2 for linearity both p < 0.001. Deep scars were more common in infected (93%) than noninfected wounds (29%), p < 0.001. We conclude that our scale is reliable and that persistence of infection 14 days after thermal injury is associated with delayed epidermal maturation and deep scarring.

The effects of octylcyanoacrylate on scarring after burns

OBJECTIVE

To compare the effects of octylcyanoacrylate (OCA), silver sulfadiazine (SSD), polyurethane film (PU), and dry gauze (G) on scarring three months after partial-thickness burns.

METHODS

This was a prospective, blinded, controlled experimental trial using isoflurane-anesthetized swine. Standardized partial-thickness burns were inflicted by applying an aluminum bar preheated to 80 degrees C to the backs and flanks of a young pig for 20 seconds. Four equal sets of ten burns each were randomly treated with OCA spray, SSD, PU, or G. Dressing changes were performed on days 1, 2, 3, and 4 after injury. Digital images of the burns were obtained immediately and three months later for masked computerized determination of scar surface area. Full-thickness biopsies were taken at three months for masked histopathological evaluation. The primary outcome was the percent reduction in residual wound area (RWA) calculated by subtracting the area of each individual burn from the area of the largest burn and dividing this value by the area of the largest burn (intraobserver correlation, r = 0.99). Secondary outcomes were the proportion of burns with the presence of scar tissue (abnormal collagen under polarized light; intraobserver agreement, kappa = 0.93) and the cosmetic appearance on a 100-mm visual analog scale marked "best scar" at the high end (inter-observer correlation, r = 0.82). Analysis of variance (ANOVA) and chi(2) tests were used for group comparisons as appropriate. This study had 80% power to detect a 33-percentage-point difference in RWA among groups (alpha = 0.05).

RESULTS

A total of 40 burns were inflicted on the pig. There was no difference in percent RWA across the groups (OCA = 25%, SSD = 40%, PU = 25%, G = 32%; p = 0.13). There was no difference in the proportion of wounds with scarring among the groups (OCA = 10%, SSD = 22%, PU = 2%, G = 30%; p = 0.89). There was also no difference in the cosmetic scores among the groups (OCA = 78 mm, SSD = 75 mm, PU = 74 mm, G = 74 mm; p = 0.96).

CONCLUSIONS

The effects of OCA spray, SSD, PU, and dry gauze on scarring three months after burns in pigs are similar.