Genetic risk factors for hypertrophic scar development

Genetic influence on scar vascularity after burn injury in individuals of European ancestry: A prospective cohort study

After burn injury there is considerable variation in scar outcome, partially due to genetic factors. Scar vascularity is one characteristic that varies between individuals, and this study aimed to identify genetic variants contributing to different scar vascularity outcomes. An exome-wide array association study and gene pathway analysis was performed on a prospective cohort of 665 patients of European ancestry treated for burn injury, using their scar vascularity (SV) sub-score, part of the modified Vancouver Scar Scale (mVSS), as an outcome measure. DNA was genotyped using the Infinium HumanCoreExome-24 BeadChip, imputed to the Haplotype Reference Consortium panel. Associations between genetic variants (single nucleotide polymorphisms) and SV were estimated using an additive genetic model adjusting for sex, age, % total body surface area and number of surgical procedures, utilising linear and multinomial logistic regression. No individual genetic variants achieved the cut-off threshold for significance. Gene sets were also analysed using the Functional Mapping and Annotation (FUMA) platform, in which biological processes indirectly related to angiogenesis were significantly represented. This study suggests that SNPs in genes associated with angiogenesis may influence SV, but further studies with larger datasets are essential to validate these findings.

The impact of burn injuries on indigenous populations: A literature review

INTRODUCTION

Ethnic minorities experience disparities in prevention and treatment of burn injury. Research focused on burn injuries in Indigenous populations is limited. This review summarizes literature on burn injuries in Indigenous populations to be considered to inform new research.

METHODS

A search was conducted in CINAHL, Ovid MEDLINE, PSYCinfo and SocINDEX. for "burn OR scars OR scald OR deformity OR disfigurement" and "Aboriginal OR Indigenous OR First Nation OR American Indian OR Maori OR Native OR Torres Strait Islander OR Amerindian OR Inuit OR Metis OR Pacific Islander". Inclusion 1) peer reviewed studies of burns in Indigenous persons 2) in English. Exclusion 1) no data specific to Indigenous burns 2) not peer reviewed 3) not in full text 4) protocol publications.

RESULTS

The search identified 1091 studies with 51 for review. Sixteen were excluded. The 35 included publications were published between 1987 and 2022. Findings indicated higher incidence of injury and poorer outcomes amongst Indigenous people. Indigenous people suffered more flame and inhalation burns, had longer lengths of stay, and more complications including hypertrophic scarring. Australian Indigenous patients struggle with a lack of culturally safe communication and support for aftercare.

CONCLUSION

Racial disparities exist in burn injury incidence and outcome for Indigenous persons. Qualitative research in this area will help providers better understand the experiences of Indigenous burn patients to develop more culturally competent care. We are currently developing a study using qualitative hermeneutic methodology to learn about the experiences of Indigenous burn survivors' injuries, recovery, and social reintegration.

Global insights into keloid formation: An international systematic review of regional genetic risk factors and commonalities

Keloid disorder is a morbid and disfiguring benign fibroproliferative disease with a higher incidence in groups with darker skin pigmentation. Predicting keloidogenesis in patients is difficult with treatment primarily aimed at preventing further scar expansion and improving aesthetics without addressing their unknown underlying pathophysiology. We aimed to identify potential genetic predispositions to keloid scarring in the literature. A search was conducted on 21 August 2023, by the first and second authors independently from 1985 to August 2023 using PubMed, MEDLINE, Embase, Web of Science, Scopus and CINAHL. The following MeSH terms were used: 'Keloid', 'Risk' and 'Genetic'. Two researchers independently searched for studies based on titles and abstracts and screened filtered articles by reviewing full text. If no agreement could be reached, a third senior author designated whether the article should be included. We used the Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2020 statement as the basis of our organisation. Human studies with genetic analysis to determine an association of a protein or gene to keloidogenesis were selected for inclusion. Studies in languages other than English, reviews, conference articles, and book chapters were excluded. Fifty studies met inclusion criteria. The human leukocyte antigen (HLA) system was broadly implicated, and the DRB1*15 allele was associated with an increased risk of keloid in three separate ethnic groups. Some HLA Class I alleles were associated with keloid in one population but not in others. Additionally, polymorphisms in the E3 ubiquitin-protein ligase (NEDD4) signal cascade and vitamin D receptor (VDR) have been implicated in diverse groups. No current genetic test can predict keloid risk. Our review identified candidate predisposing genes, including NEDD4, VDR and components of the HLA system. Further studies in heterogeneous populations are needed to identify reliable screening targets.

Efficacy of fractional carbon dioxide laser-assisted drug delivery in the management of post-burn scars - A prospective study

Objectives

The objective of our study is to assess the efficacy of fractional carbon dioxide (CO2) laser-assisted drug delivery (LADD) in the management of post-burn scars.

Material and Methods

It is a prospective study conducted from March 2021 to February 2022, with 32 patients ranging in age from 9 to 52 years. The scars lasted anywhere from 6 months to 18 years. The ethical clearance of the Institutional Ethics Committee was obtained. The patient's median age was 22 (range, 09-52). Patients were assessed using a modified Vancouver scar scale (mVSS) score before and after receiving fractional CO2 laser at monthly intervals.

Results

After one treatment, statistically significant improvements in pigment, thickness, and pliability were seen according to the mVSS scores, and these improvements persisted through the final laser session.

Conclusion

Our study has demonstrated that fractional CO2 LADD seems to be an encouraging approach in the management of post-burn scars with good patient satisfaction.

The Art of Local Tissue Rearrangements in Burn Reconstruction: Z-Plasty and More

In recent decades, advances in surgical anatomy, burn pathophysiology, surgical techniques, and laser therapy have led to a paradigm shift in how we approach burn scars and contractures. Scar excision and replacement with uninjured tissue, which predominated burn scar treatment for much of the 20th century, is no longer appropriate in many patients. A scar's intrinsic ability to remodel can be induced by reducing tension on the scar using various techniques for local tissue rearrangement. Often in combination with laser therapy, local flaps can optimally camouflage a burn scar with adjacent normal tissue and restore a patient more closely to their preinjury condition.

miRSNP rs188493331: A key player in genetic control of microRNA-induced pathway activation in hypertrophic scars and keloids

BACKGROUND

Our study aims to delineate the miRSNP-microRNA-gene-pathway interactions in the context of hypertrophic scars (HS) and keloids.

MATERIALS AND METHODS

We performed a computational biology study involving differential expression analysis to identify genes and their mRNAs in HS and keloid tissues compared to normal skin, identifying key hub genes and enriching their functional roles, comprehensively analyzing microRNA-target genes and related signaling pathways through bioinformatics, identifying MiRSNPs, and constructing a pathway-based network to illustrate miRSNP-miRNA-gene-signaling pathway interactions.

RESULTS

Our results revealed a total of 429 hub genes, with a strong enrichment in signaling pathways related to proteoglycans in cancer, focal adhesion, TGF-β, PI3K/Akt, and EGFR tyrosine kinase inhibitor resistance. Particularly noteworthy was the substantial crosstalk between the focal adhesion and PI3K/Akt signaling pathways, making them more susceptible to regulation by microRNAs. We also identified specific miRNAs, including miRNA-1279, miRNA-429, and miRNA-302e, which harbored multiple SNP loci, with miRSNPs rs188493331 and rs78979933 exerting control over a significant number of miRNA target genes. Furthermore, we observed that miRSNP rs188493331 shared a location with microRNA302e, microRNA202a-3p, and microRNA20b-5p, and these three microRNAs collectively targeted the gene LAMA3, which is integral to the focal adhesion signaling pathway.

CONCLUSIONS

The study successfully unveils the complex interactions between miRSNPs, miRNAs, genes, and signaling pathways, shedding light on the genetic factors contributing to HS and keloid formation.

Three-dimensional bioprinting of tissue-engineered skin: Biomaterials, fabrication techniques, challenging difficulties, and future directions: A review

As an emerging new manufacturing technology, Three-dimensional (3D) bioprinting provides the potential for the biomimetic construction of multifaceted and intricate architectures of functional integument, particularly functional biomimetic dermal structures inclusive of cutaneous appendages. Although the tissue-engineered skin with complete biological activity and physiological functions is still cannot be manufactured, it is believed that with the advances in matrix materials, molding process, and biotechnology, a new generation of physiologically active skin will be born in the future. In pursuit of furnishing readers and researchers involved in relevant research to have a systematic and comprehensive understanding of 3D printed tissue-engineered skin, this paper furnishes an exegesis on the prevailing research landscape, formidable obstacles, and forthcoming trajectories within the sphere of tissue-engineered skin, including: (1) the prevalent biomaterials (collagen, chitosan, agarose, alginate, etc.) routinely employed in tissue-engineered skin, and a discerning analysis and comparison of their respective merits, demerits, and inherent characteristics; (2) the underlying principles and distinguishing attributes of various current printing methodologies utilized in tissue-engineered skin fabrication; (3) the present research status and progression in the realm of tissue-engineered biomimetic skin; (4) meticulous scrutiny and summation of the extant research underpinning tissue-engineered skin inform the identification of prevailing challenges and issues.

How to evaluate scar colour after burn injuries - A clinical comparison of the Mexameter® and the subjective scar assessment (POSAS/VSS)

INTRODUCTION

Scarring after burn injuries remains one of the major challenges in burn medicine and is the subject of current research. Accurate and high-quality assessment of scars is needed to enable exact outcome evaluation of different treatments. Our aim was to evaluate the most common subjective scar evaluation scores-the POSAS (Patient and Observer Scar Assessment Scale) and VSS (Vancouver Scar Scale)-in comparison with the objective device Mexameter® for colour evaluation.

METHODS

A prospective monocentre study was performed, which included 120 examined scar areas of 60 patients with third degree burns who had received skin grafts between 1975 and 2018 with a total burned surface area (TBSA) > 2%. Two different scar areas in comparison with one healthy skin area concerning 'colour', 'pigmentation', and 'vascularization' were evaluated by the Mexameter® MX 18, the OSAS, and the VSS by the same examiner, as well as the PSAS by the patient.

RESULTS

The mean TBSA of the 60 patients was 24.3%. In the OSAS, 61% of the scars were evaluated as 'hyper-', 19% as 'hypo-', and 19% as 'mix-pigmented'. Furthermore, 65% of the scars were estimated as highly vascularized. In the Mexameter®, the melanin index values of the scar areas compared to the healthy skin areas showed a small difference of 12 (p < 0.05). The mean difference of erythema between the scar and the healthy skin areas was 84 (p < 0.001). For the Mexameter®, moderate correlations were found when comparing 'erythema' with the OSAS category 'vascularization' (r = 0.33, p < 0.05) and 'melanin' with the OSAS parameter 'pigmentation' (r = 0.28, p < 0.05). When comparing the Mexameter® measurements to the OSAS questionnaire, 27% of the scars were wrongly evaluated as 'hyperpigmented' by the observer and 21% as 'hypervascularized', while showing low measurements in the device. Additionally, a novel Mexameter® ordinal scare scale was calculated.

CONCLUSION

In this study, we were able to show on a relatively large patient population that with the Mexameter®, the subjectivity of the scar colour assessment by examiner/patient can be overcome, but precise differentiation can still be ensured with subjective evaluation tools. We further introduced a novel Mexameter® Scar Scale. It is necessary to further investigate the vast range of objective devices and develop scar panels for with an incorporation of objective and subjective devices to further improve reliability with reduced bias in terms of scar assessment.

Rete ridges are decreased in dyschromic burn hypertrophic scar: A histological study

Dyschromic hypertrophic scar (HTS) is a common sequelae of burn injury, however, its mechanism has not been elucidated. This work is a histological study of these scars with a focus on rete ridges. Rete ridges are important for normal skin physiology, and their absence or presence may hold mechanistic significance in post-burn HTS dyschromia. It was posited that hyper-, and hypo-pigmented areas of scars have different numbers of rete ridges. Subjects with dyschromic burn hypertrophic scar were prospectively enrolled (n = 44). Punch biopsies of hyper-, hypo-, and normally pigmented scar and skin were collected. Biopsies were paraffin embedded, sectioned, stained with H&E, and imaged. The number of rete ridges were investigated. Burn hypertrophic scars that healed without autografts were first investigated. The number of rete ridges was higher in normal skin compared to HTS that was either hypo- (p < 0.01) or hyper-pigmented (p < 0.001). This difference was similar despite scar pigmentation phenotype (p = 0.8687). Autografted hyper-pigmented scars had higher rete ridge ratio compared to non-autografted hyper-pigmented HTS (p < 0.0001). Burn hypertrophihc scars have fewer rete ridges than normal skin. This finding may explain the decreased epidermal adherence to underlying dermis associated with hypertrophic scars. Though, contrary to our hypothesis, no direct link between the extent of dyschromia and rete ridge quantity was observed, the differences in normal skin and hypertrophic scar may lead to further understanding of dyschromic scars.

Practical management of hypertrophic scarring: the mayo clinic experience

Hypertrophic scarring is a potential consequence of wound healing that causes functional and aesthetic disability. Common treatments include intralesional pharmacotherapy (e.g., triamcinolone), surgical excision, and energy-based laser devices. While numerous treatment methods have been described for hypertrophic scarring, an optimal treatment strategy has yet to be established given variability in clinical presentation. This study aims to identify patient- and provider-preferred treatment patterns. This is a single-center, retrospective study of adult patients that developed post-surgical hypertrophic scarring between 2007 and 2017. Specifically, trends in procedural management for hypertrophic scarring among this cohort were examined. A total of 442 procedures (intralesional steroid injection, surgical excision, laser-based treatment) were identified in 218 patients with a clinical diagnosis of hypertrophic scarring. Approximately 73% were female; 87% were Caucasian. The median age at first procedure was 45.6 years (SD = 17.4). The most frequent anatomical locations for procedures were the trunk (n = 242; 54.8%), followed by head/neck (n = 86; 19.5%), upper extremities (n = 67; 15.2%), and lower extremities (n = 45; 10.2%). Procedural therapies included intralesional steroid injection (n = 221; 50%), surgical excision (n = 112; 25.3%) and laser (fractional non-ablative laser vs. pulsed dye laser; n = 109; 24.5%). Treatment modality varied by stage of treatment, scar anatomical location, and scar size. This single-center series of patients with hypertrophic scarring highlights a patient-centered management approach and offers clinical guidelines for provider-patient shared decision making.

Comparing the Effectiveness of Glucocorticoids in Preventing Hypertrophic Scar Diagnosis in Burn Patients

Background and Objectives: The prevalence of hypertrophic scarring after a burn is approximately 70%. Despite advances in burn management, there is currently no gold standard treatment to reduce or prevent its occurrence. Glucocorticoids are frequently given to patients early after burns for other therapeutic purposes and have been shown to induce scar regression. Therefore, the purpose of the present work is to determine the incidence of hypertrophic scar diagnosis in burn patients who were administered glucocorticoid treatment using TriNetX, a large patient database. Materials and Methods: Patients diagnosed with hypertrophic scarring, hypertrophic disorders of the skin, or scar conditions and fibrosis of the skin after burn injury were identified in the TriNetX database. The glucocorticoids investigated include hydrocortisone, methylprednisolone, dexamethasone, triamcinolone, and prednisone. Patients were stratified into three groups based on total body surface area (TBSA) burned: 0-19%, 20-39%, and 40-100%. The risk ratio was evaluated for burn patients who received varying glucocorticoids after injury based on TBSA burned. Additionally, treatment pathways, time of treatment, and treatment purity pathways were evaluated. Results: In patients with a 0-19% TBSA burn, methylprednisolone showed a decreased risk of developing hypertrophic scar diagnosis. In those with a 20-39% TBSA burn or 40-100% TBSA burn, dexamethasone showed an increased risk of developing hypertrophic scar diagnosis. Additionally, dexamethasone was the most commonly administered glucocorticoid for burn patients and was most likely to be administered earlier after burn injury, comparatively. Conclusions: Methylprednisolone was associated with reduced hypertrophic scar diagnosis in burn patients independent of TBSA burn. While glucocorticoids are one of the mainstay treatments for hypertrophic scarring, further studies are needed to determine early therapeutic interventions that will reduce the potential for hypertrophic scar development in burn patients.

A role for vitamin D and the vitamin D receptor in keloid disorder

Keloids are disfiguring fibroproliferative lesions that can occur in susceptible individuals following any skin injury. They are extremely challenging to treat, with relatively low response rates to current therapies and high rates of recurrence after treatment. Although several distinct genetic loci have been associated with keloid formation in different populations, there has been no single causative gene yet identified and the molecular mechanisms guiding keloid development are incompletely understood. Further, although it is well known that keloids are more commonly observed in populations with dark skin pigmentation, the basis for increased keloid risk in skin of colour is not yet known. Because individuals with dark skin pigmentation are at higher risk for vitamin D deficiency, the role of vitamin D in keloid pathology has gained interest in the keloid research community. A limited number of studies have found lower serum vitamin D levels in patients with keloids, and reduced expression of the vitamin D receptor (VDR) in keloid lesions compared with uninjured skin. Vitamin D has documented anti-inflammatory, anti-proliferative and pro-differentiation activities, suggesting it may have a therapeutic role in suppression of keloid fibrosis. Here we review the evidence supporting a role for vitamin D and VDR in keloid pathology.

Treatment of traumatic hypertrophic scars and keloids: a systematic review of randomized control trials

Exaggerated healing and remodeling after skin injury may cause hypertrophic and keloidal scars, which are associated with functional and quality of life impairment. There is limited guidance available regarding the relative effectiveness of therapies for hypertrophic scars and keloids. In this review, we aim to compare the effectiveness of treatments for hypertrophic scars and keloids. MEDLINE, Embase, Scopus, and the Cochrane Collaboration database were searched from inception to March 2019 for randomized control trials of treatments for hypertrophic and keloid scars that included 20 or more patients. Outcomes evaluated included the standardized mean reduction in scarring and adverse events. The type of scar and the demographic features were analyzed for their effect on clinical outcome. Based on 25 included clinical trials, intralesional injection (64.1% [95% CI 60.8-67.5%]) may be more effective than physical (29.9% [95% CI 28.9-30.9%]) or topical treatments (34% [95% CI 31.8-36.8%]). Combination of 5-fluorouracil and triamcinolone (9:1 dilution) appeared superior among intralesional treatments for keloids. Ablative laser and pulsed-dye laser were the most useful laser treatments. Regression modeling showed laser treatment response was linked to Fitzpatrick skin type (p = 0.002). Adverse events were uncommon for all treatments and mostly transient. Intralesional treatments for keloid and hypertrophic scars may be the most reliable treatment option to improve pathologic scars, while laser treatment may have specific benefits for Fitzpatrick skin types I-III over types IV-VI. Management of pathological scars is an area of critical need, where appropriate treatment can have a significant impact on quality of life.

An Updated Review of Hypertrophic Scarring

Hypertrophic scarring (HTS) is an aberrant form of wound healing that is associated with excessive deposition of extracellular matrix and connective tissue at the site of injury. In this review article, we provide an overview of normal (acute) wound healing phases (hemostasis, inflammation, proliferation, and remodeling). We next discuss the dysregulated and/or impaired mechanisms in wound healing phases that are associated with HTS development. We next discuss the animal models of HTS and their limitations, and review the current and emerging treatments of HTS.

Clarifying sleep characteristics and analyzing risk factors of sleep disorders to promote a predictive, preventive, and personalized medicine in patients with burn scars

Purpose

This study assessed sleep quality in patients with burn scars and investigated risk factors of sleep disorders to guide clinical therapy. From the strategy of predictive, preventive, and personalized medicine (PPPM/3PM), we proposed that risk assessment based on clinical indicators could prompt primary prediction, targeted prevention, and personalized interventions to improve the management of sleep disorders present in patients with burn scars.

Methods

This retrospective study recruited patients with burn scars and healthy volunteers from the Shanghai Burn Treatment Center between 2017 and 2022. Relevant information and data, including demographic characteristics, scar evaluation, and sleep quality, were obtained through the hospital information system, classical scar scale, and self-report questionnaires. Sleep quality was assessed using the Pittsburgh Sleep Quality Index (PSQI) and monitored using a cardiopulmonary-coupled electrocardiograph. Pain and pruritus were assessed using the visual analog scale (VAS). Scar appearance was assessed using the modified Vancouver scar scale (mVSS).

Results

The sample was comprised of 128 hypertrophic scar (HS) patients, with 61.7% males, a mean age of 41.1 ± 11.6 years, and burn area of 46.2 ± 27.9% total body surface area (TBSA). Patients with PSQI ≥ 7 accounted for 76.6%, and the global PSQI score was 9.4 ± 4.1. Objective sleep data showed that initial enter deep sleep time, light sleep time, awakening time, light sleep efficiency, and sleep apnea index were higher but deep sleep time, sleep efficiency, and deep sleep efficiency were lower in HS patients than that in healthy controls. Preliminary univariate analysis showed that age, hyperplasia time of scar, narrow airway, microstomia, VAS for pain and pruritus, and mVSS total (comprised of pigmentation, vascularity, height and pliability) were associated with the PSQI score (p < 0.1). Multivariable linear regression showed narrow airway, VAS for pain and pruritus, and mVSS specifically height, were the risk factors for PSQI score (p < 0.1).

Conclusions

This study model identified that narrow airway, pain, pruritus and scar appearance specifically height may provide excellent predictors for sleep disorders in HS patients. Our results provided a basis for the predictive diagnostics, targeted prevention, and individualized therapy of somnipathy predisposition and progression of HS patients in the setting of PPPM/3PM health care system, which contributed to a paradigm shift from reactive cure to advanced therapy.

Description of Novel Technique for Managing Insufficient Nasal Skin Volume

A short nose is a common esthetic problem faced by facial plastic surgeons. Rhinoplasty of the short nose has been recognized as a complex procedure to perform for achieving satisfactory results. The authors presented 4 cases of short nose in 4 Saudi men who underwent rhinoplasty using septal extension graft and closure the skin with secondary intention as an option to control skin tension after graft placement and to increase nose skin volume to prevent skin retraction, which may occur postoperatively during the healing process. Furthermore, the authors have also discussed the surgical outcomes of these 4 cases and overall satisfaction. Finally, the authors reviewed the literature to identify published papers on correcting the short nose technique.

Biofabrication of Human Skin with Its Appendages

Much effort has been made to generate human skin organ in the laboratory. Yet, the current models are limited due to the lack of many critical biological and structural features of the skin. Importantly, these in vitro models lack appendages and fail to recapitulate the whole human skin construction. Thus, engineering a human skin with the capacity to generate all components, including appendages, is a major challenge. This review intends to provide an update on the recent efforts underway to regenerate appendage-bearing skin organs based on scaffold-free and scaffold-based bioengineering approaches. Although the mouse skin equivalents containing hair follicles, sebaceous glands, and sweat glands have been established in vitro, there has been limited success in humans. A combination of biofabricated matrices and cell aggregates, such as organoids, can pave the way for generating skin substitutes with human-like biological, structural, and physical features. Accordingly, the formation of human skin organoids and reconstruction of vascularized skin equipped with immune cells prompt calls for more scientific research. The generation of appendage-bearing skin substitutes can be applied in practice for wound healing, hair restoration, and scar treatment.

Diagnosis, Treatment, and Management of Painful Scar: A Narrative Review

Painful scars can develop after surgery or trauma, with symptoms ranging from a minor itch to intractable allodynia. The problem of the painful scar may involve both intraneural and extraneural structures, requiring a systematic approach to diagnosis and treatment of this neuropathic pain condition that can impact quality of life and function profoundly. In this review, we outline the algorithm for the diagnosis, management, medical and surgical treatment of painful scars.

The Impact of Race/Ethnicity on the Outcomes of Burn Patients: A Systematic Review of the Literature

Racial and ethnic disparities are endemic to the United States and are only beginning to attract the attention of researchers. With an increasingly diverse population, focused and tailored medicine to provide more equitable care is needed. For surgical trauma populations, this topic is a small but expanding field and still rarely mentioned in burn medicine. Disparities in prevention, treatment, and recovery outcomes between different racial and ethnic minorities who are burned are rarely discussed. The purpose of this study is to determine the current status of identified disparities of care in the burn population literature and areas of future research. A systematic review was conducted of literature utilizing PubMed for articles published between 2000 and 2020. Searches were used to identify articles that crossed the burn term (burn patient OR burn recovery OR burn survivor OR burn care) and a race/ethnicity and insurance status-related term (race/ethnicity OR African-American OR Black OR Asian OR Hispanic OR Latino OR Native American OR Indigenous OR Mixed race OR 2 or more races OR socioeconomic status OR insurance status). Inclusion criteria were English studies in the United States that discussed disparities in burn injury outcomes or risk factors associated with race/ethnicity. One thousand one hundred and sixty-nine papers were populated, 55 were reviewed, and 36 articles met inclusion criteria. Most studies showed minorities had poorer inpatient and outpatient outcomes. While this is a concerning trend, there is a paucity of literature in this field and more research is needed to create culturally tailored medical care and address the needs of disadvantaged burn survivors.

Longitudinal monitoring and prediction of long-term outcome of scar stiffness on pediatric patients

Background

Hypertrophic scarring after burn injury is one of the greatest unmet challenges in patients with burn injuries. A better understanding of the characteristics of scar maturation and early prediction of the long-term outcome of scarring are prerequisites for improving targeted therapies and pivotal for patient counselling.

Methods

Repeated measurements of scar stiffness in 11 pediatric patients were performed over the course of 1 year using 2 suction devices, the Cutometer and the Nimble. In addition, the observer pliability score of the Patient and Observer Scar Assessment Scale was applied. This longitudinal study allowed quantification of the ability of each of the measured parameters to reflect scar maturation, as indicated by change in skin pliability/stiffness, over time (using linear regression); the ability to distinguish individual patients (intraclass correlation coefficient (ICC)); the correlation of the devices (Spearman correlation coefficient); and the ability to predict long-term scar maturation based on early scar assessment (using receiver operating characteristic).

Results

All the tools used showed significant longitudinal decrease of scar stiffness from 3 months until 12 months after the injury. The Nimble (ICC_patient ^Nimble = 0.99) and the Cutometer (ICC_patient ^Cuto = 0.97) demonstrated an excellent ability to distinguish between individual patients. The Nimble seemed to be able to predict the 12-month pliability of scars based on early (3-month) measurements (area under the curve (AUC)_12m ^POSAS = 0.67; AUC_12m ^C = 0.46; AUC_12m ^N = 0.79).

Conclusions

The results of this preliminary study suggest that all 3 tools provide suitable means to quantify alterations in scar stiffness over time. Initial evidence suggests the Nimble is most favorable for predicting changes in stiffness associated with long-term scar maturation. Further studies with a larger sample size are required to validate tissue suction as a clinical tool for analysis of changes of scar stiffness over time.

A Scoping Review of the Methodology Used in Studies of Genetic Influences on the Development of Keloid or Hypertrophic Scarring in Adults and Children After Acute Wounding

Significance: Keloid and hypertrophic scarring are common following acute wounds. However, the variability in scarring outcomes between individuals and in particular, the association between genetic factors and scarring, is not well understood. This scoping review aims to summarize the methodology used in studies of genetic influences on the development of keloid or hypertrophic scarring in adults and children after acute wounding. The objectives were to determine the study designs used, the characteristics of participants included, the tools used to assess scarring and the length of follow-up after wounding.

Recent Advances: The review was conducted according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Medline, Excerpta Medica Database (EMBASE), Web of Science, Biosciences Information Service (BIOSIS), Prospective Register of Systematic Reviews (PROSPERO), The Human Genetic Epidemiology (HuGE) Navigator (database of genetic association studies), and the genome-wide association study Catalog were searched from January 2008 to April 2020. Cohort studies and case–control studies that examined the association between one or more genetic variations and the development of keloid or hypertrophic scarring were eligible for inclusion. A narrative synthesis that grouped studies by wound type was conducted.

Critical Issues: Nine studies met the inclusion criteria (five in burns, four surgical wounds, and none in other types of acute wounds). Seven assessed hypertrophic scarring, one keloid scarring, and one both scar types. Seven studies used a prospective cohort design. All studies used subjective methods (clinician or patient observation) to assess scarring. There was considerable variation in how scar scales were operationalized.

Future Directions: This review identified a small body of evidence on genetic susceptibility to scarring after acute wounding. Further studies are needed, and in a wide range of populations, including patients with wounds caused by trauma.

Representation Matters: An Assessment of Diversity in Current Major Textbooks on Burn Care

Ethnic and gender disparities in healthcare have been well described. Increasing attention is paid to representative diversity in the images and educational resources used during medical training. Nearly 40% of the population of the United States identifies as a person of color, and patients of color reflect 41% of the total burn population seen in the United States. Additionally, national data on providers suggest about 5% of the Burn Team should be people of color. A better understanding of the diversity represented by burn-related medical literature could affect the management of patients with diverse backgrounds, as well as recruitment of black, indigenous, and people of color (BIPOC) into this field. The goal of this study is to investigate the representation of diverse skin tones in several leading medical textbooks of burn care. All photographs that contained people were evaluated for the number of people present and the depicted role of the person present. Diversity count was assessed in a binary fashion-was the individual represented a BIPOC? About 2579 total individuals were identified. BIPOC was represented in 363 total images (14%). There were 6 providers of color identified out of a total of 161 (3.7%); 30 providers were women (19%), of whom only 1 was a female provider of color. BIPOC patients and providers are underrepresented in the leading textbooks of burn care. Proper representation must be included in modern educational materials to better prepare providers for a diverse population of burn-injured patients and ensure effective and thoughtful care.

Chronic itch in African Americans: an unmet need

Chronic pruritus carries a significant burden of disease and is associated with a negative impact on quality of life. African Americans are disproportionately burdened by chronic pruritic disorders, including but not limited to atopic dermatitis, prurigo nodularis, inflammatory scalp dermatoses, pathologic scarring, and HIV-related dermatoses. Racial differences in skin structure and function may contribute to the pathogenesis of itch in African Americans. Itch perception and response to treatment in African Americans remain understudied and not well understood. As such, there is a large unmet need with regard to the knowledge and management of pruritus in African Americans. This review highlights notable differences in the epidemiology, pathophysiology, genetic predisposition, clinical presentation, and response to treatment for select pruritic skin conditions. By addressing itch as an unmet need in African Americans, we hope to improve patient outcomes and lessen disparities in dermatologic care.

3D bioprinting for skin tissue engineering: Current status and perspectives

Skin and skin appendages are vulnerable to injury, requiring rapidly reliable regeneration methods. In recent years, 3D bioprinting has shown potential for wound repair and regeneration. 3D bioprinting can be customized for skin shape with cells and other materials distributed precisely, achieving rapid and reliable production of bionic skin substitutes, therefore, meeting clinical and industrial requirements. Additionally, it has excellent performance with high resolution, flexibility, reproducibility, and high throughput, showing great potential for the fabrication of tissue-engineered skin. This review introduces the common techniques of 3D bioprinting and their application in skin tissue engineering, focusing on the latest research progress in skin appendages (hair follicles and sweat glands) and vascularization, and summarizes current challenges and future development of 3D skin printing.

Scarring at Donor Sites after Split-Thickness Skin Graft: A Prospective, Longitudinal, Randomized Trial

OBJECTIVE

To investigate if previous findings on the association between dressing treatments and subjective opinion on final donor site scar outcome using the Patient and Observer Scar Assessment Scale (POSAS) can be confirmed objectively. The previous study showed that patients dressed with hydrofiber covered with film were more satisfied with their donor site scars than patients receiving porcine xenograft or polyurethane foam dressings.

METHODS

Scar outcome measurements were assessed by a blinded observer using POSAS and the Cutometer dual MPA 580 device to measure the viscoelasticity of skin.

RESULTS

A total of 17 participants were included in this study, five of whom were treated with hydrofiber, six with polyurethane foam, and another six with porcine xenograft. There were no significant differences among groups in any of the POSAS items or in the viscoelasticity measurements made with the Cutometer.

CONCLUSIONS

The investigators could not confirm previous associations between dressing treatment and long-term donor site scars. No associations between donor sites' healing times and final scarring were found. Hypopigmentation was reported in 15 of 17 donor sites evaluated.

Correlation Between the Warrior/Worrier Gene on Post Burn Pruritus and Scarring: A Prospective Cohort Study

INTRODUCTION

Associations between genetic variation and clinical conditions suggest that single nucleotide polymorphisms (SNPs) might correlate with postburn outcomes. COMT modulates catecholamine metabolism, and polymorphisms within the rs4680 allele result in variable enzyme activity. Catecholamines are known to modulate the inflammatory process and may affect scar formation. The aim of this study was to determine whether variants in the rs4680 SNP of the COMT gene are associated with post-burn pruritus and scarring.

METHODS

Adult burn patients, admitted between 2007 and 2017, with deep partial-thickness burns or delayed healing provided blood samples for genotyping and self-reported itch scores within 1 year of injury. Scarring was measured using the Vancouver Scar Scale (VSS). Itch scores ≥4 and VSS scores >7 were considered severe. Genomic deoxyribonucleic acid was genotyped for the rs4680 SNP using realtime polymerase chain reaction (PCR).

RESULTS

Median itch and VSS scores were highest for GG homozygotes and lowest for AA homozygotes. This difference was statistically significant for VSS score (P < 0.0001) and approached significance for itch (P = 0.052). After accounting for confounding variables, including race/ethnicity, age, sex, and burn size, the GG homozygotes demonstrated worse scarring (odds ratio 1.88, P = 0.005) compared to AG heterozygotes whereas the AA homozygotes trended towards a protective effect against scarring (odds ratio 0.71, P = 0.10). Itch did not demonstrate a statistically significant difference between rs4680 genotype.

CONCLUSIONS

Our analysis identifies a trend between COMT genotype with scarring, with rs4680 genetic variation constituting an independent risk factor for VSS score.

Sprayed cultured autologous keratinocytes in the treatment of severe burns: a retrospective matched cohort study

The standard treatment of burns is early excision followed by autologous skin grafting. The closure of extensive deep burns poses a considerable challenge. Cultured autologous keratinocytes have been used since 1981 in an effort to improve healing. However, the time required to culture the cells and the lack of a dermal component limit the expectations of outcome. Our aim was to compare the duration of hospital stay between patients who were treated with autologous skin grafts and cultured autologous keratinocytes and those who were treated with autologous skin grafting without cultured autologous keratinocytes. In this retrospective study all patients treated with cultured autologous keratinocytes between 2012 and 2015 were matched by size and depth of burn with patients not treated with cultured autologous keratinocytes. Multivariable regression was used to analyse associations between duration of hospital stay and treatment adjusted for age, mortality, size and depth of the burn. Then, we investigated the possibility of differentiation of human bone marrow stem cell line to keratinocyte- like cells as a future direction. The regression analysis showed a coefficient of 17.36 (95% CI -17.69 to 52.40), p= 0.32, for hospital stay in the treatment group, compared with the matched group. Our results showed no difference in the duration of hospital stay between the two treatments. Autologous stem cells should be considered as a future modality of burn management, although further studies are needed.

Regeneration of skin appendages and nerves: current status and further challenges

Tissue-engineered skin (TES), as an analogue of native skin, is promising for wound repair and regeneration. However, a major drawback of TES products is a lack of skin appendages and nerves to enhance skin healing, structural integrity and skin vitality. Skin appendages and nerves are important constituents for fully functional skin. To date, many studies have yielded remarkable results in the field of skin appendages reconstruction and nerve regeneration. However, patients often complain about a loss of skin sensation and even cutaneous chronic pain. Restoration of pain, temperature, and touch perceptions should now be a major challenge to solve in order to improve patients’ quality of life. Current strategies to create skin appendages and sensory nerve regeneration are mainly based on different types of seeding cells, scaffold materials, bioactive factors and involved signaling pathways. This article provides a comprehensive overview of different strategies for, and advances in, skin appendages and sensory nerve regeneration, which is an important issue in the field of tissue engineering and regenerative medicine.

Effect of ethanol extract from Lactobacillus plantarum TWK10-fermented soymilk on wound healing in streptozotocin-induced diabetic rat

Wound healing is a highly dynamic phenomenon comprising numerous coordinated steps including homeostasis/coagulation, inflammation, migration, proliferation, and remodeling. Diabetes mellitus (DM) is a multisystem chronic epidemic that prolongs inflammation in wounds and is associated with impaired healing. This study aimed to investigate the effect of an ethanol extract from Lactobacillus plantarum TWK10 (TWK10)-fermented soymilk on wound healing. The anti-inflammatory effects of the ethanol extract of TWK10-fermented soymilk on lipopolysaccharide-stimulated RAW264.7 macrophage cells were examined. The ethanol extract of TWK10-fermented soymilk (100 µg/mL) significantly decreased nitric oxide production from 11.34 ± 0.74 μM to 8.24 ± 2.02 µM (p < 0.05) and enhanced proliferation in Detroit 551 cells cultured in high-glucose medium; the cell number peaked at 128.44 ± 7.67% (compared to the untreated control) at 600 µg/mL. An ethanol extract of TWK10-fermented soymilk + vaseline-treated rat model of streptozotocin-induced diabetic wounds was generated herein, and the following groups were formed herein: normal control (NC), blank control (BC), low dose group (LD, 0.24 mg/wound), intermediate dose (MD, 0.48 mg/wound), and high dose (HD, 2.40 mg/wound). On day 14 after wound infliction, the wound area in the LD, MD, and HD groups was significantly decreased to 10.2, 8.4, and 8.5% respectively (p < 0.05). Moreover, in the LD, MD, and, HD groups, tumor necrosis factor-α, interleukin 6, and matrix metalloproteinase-9 were downregulated in the wounded skin. These results show that the topical application of the ethanol extract of TWK10-fermented soymilk is beneficial for enhancing wound healing and for the closure of diabetic wounds.

Effect of Topical Garlic on Wound Healing and Scarring: A Clinical Trial

BACKGROUND

Historically, garlic containing compounds have been used on wounds to improve healing and ward off infection. Researchers have tested many of these ancient ointments, discovering that garlic is a common ingredient in those that are effective.

OBJECTIVE

To determine the efficacy of topical garlic on surgical wounds compared with Vaseline by analysis of visual analog scales and digital photograph analysis.

MATERIALS AND METHODS

Seventeen patients with 2 skin excisions applied a 30% garlic ointment to one surgical wound and Vaseline to the other surgical wound twice daily. They were followed up at 2 weeks and 4 weeks post-op. Digital photographs were taken of the sites, and wound visual analog scales were filled out by the patient and the physician.

RESULTS

Patients and the onsite physician stated the garlic site healed better in 59% and 65% of the wounds, respectively, at 2 weeks. At 4 weeks, the patients and the onsite physician stated the garlic site healed better in 76% and 88% of wounds, respectively. Digital photograph analysis revealed less erythema at the garlic sites (p-value = .02).

CONCLUSION

Surgical wounds treated with 30% garlic ointment healed with more cosmetically appealing scars than the Vaseline-treated sites.

Investigating the intra- and inter-rater reliability of a panel of subjective and objective burn scar measurement tools

BACKGROUND

Research into the treatment of hypertrophic burn scar is hampered by the variability and subjectivity of existing outcome measures. This study aims to measure the inter- and intra-rater reliability of a panel of subjective and objective burn scar measurement tools.

METHODS

Three independent assessors evaluated 55 scar and normal skin sites using subjective (modified Vancouver Scar Scale [mVSS] & Patient and Observer Scar Assessment Scale [POSAS]) and objective tools. The intra-class correlation coefficient was utilised to measure reliability (acceptable when >0.70). Patient satisfaction with the different tools and scar parameter importance were assessed via questionnaires.

RESULTS

The inter-rater reliabilities of the mVSS and POSAS were below the acceptable limit. For erythema and pigmentation, all of the Scanoskin and DSM II measures (except the b* value) had acceptable to excellent intra and inter-rater reliability. The Dermascan ultrasound (dermal thickness, intensity) had excellent intra- and inter-rater reliability (>0.90). The Cutometer R0 (firmness) had acceptable reliability but not R2 (gross elasticity). All objective measurement tools had good overall satisfaction scores. Patients rated scar related pain and itch as more important compared to appearance although this finding was not sustained when corrected for multiple comparisons.

CONCLUSION

The objective scar measures demonstrated acceptable to excellent intra- and inter-rater reliability and performed better than the subjective scar scales.

Joint contractures in severe burn patients with early rehabilitation intervention in one of the largest burn intensive care unit in China: a descriptive analysis

Background

Joint contracture is the major clinical complication in burn patients, especially, the severe burn patients. This study aimed to investigate the number and severity of joint contractures in patients with burns affecting greater than or equal to 50% of the total body surface area (TBSA) undergoing early rehabilitation in a burn intensive care unit (BICU).

Methods

We analyzed burn patients with burns affecting greater than or equal to 50% of the TBSA admitted to a BICU who received early rehabilitation within 7 days post-injury from January 2011 to December 2015. Demographic and medical information was collected. The range of motion (ROM) of different joints was measured 1 month post-admission. Spearman’s correlation coefficient and logistic regression analysis was used to determine predictors of the presence and severity of contractures.

Result

The average affected TBSA of the included burn patients was 67.4%, and the average length of stay in the BICU was 46.2 ± 28.8 days. One hundred and one of 108 burn patients (93.5%) developed at least one joint contracture. The ROM in 67.9% of the affected joints was mildly limited. The majority of contractures in severe burn patients were mild (37.7%) or moderate (33.2%). The wrist was the most commonly affected joint (18.2%), followed by the shoulder, ankle, hip, knee, and elbow. A predictor of the presence of contractures was the length of hospital stay (p = 0.049). The severe contracture was related to the area of full-thickness burns, the strict bed rest time, and the duration of rehabilitation in BICU. The length of rehabilitation stay (days) in patients with moderate contracture is 54.5% longer than that in severe contracture (p = 0.024)

Conclusion

During the long stay in BICU, the length of rehabilitation stay in a BICU could decrease the severity of contractures from severe to moderate in the patients with equal to 50% of the TBSA. Hence, this research reveals the important role of early rehabilitation interventions in severe burn patients.

Electronic supplementary material

The online version of this article (10.1186/s41038-019-0151-6) contains supplementary material, which is available to authorized users.

Incidence, severity and pattern of burns in children and adolescents: An epidemiological study among immigrant and Swiss patients in Switzerland

BACKGROUND

Despite advances in surgical management and critical care for burn surgery, morbidity and mortality of patients with severe burns remains high. Especially in the pediatric population, burns often lead to devastating consequences such as the necessity of corrective surgery until adulthood. Worldwide, 80%-90% of all severe burns occur in low to middle income countries. But also in high income countries, burns are distributed inequitably. Risk factors include age, sex, socioeconomic status, and ethnicity.

AIM

The objective of this study was to determine the typical demographics and injury-related data of pediatric burn patients in order to contribute to preventive measures. Special interest was paid to the question of whether the incidence of severe burns is higher among patients with an immigration background.

PATIENTS AND METHODS

Patient records of the 4373 patients admitted to the Pediatric Burn Unit of the University Children's Hospital of Zurich from 2006 to 2018 were analyzed. Demographic data and injury patterns are presented descriptively. Temporal trends concerning duration of hospitalization and setting (inpatient versus outpatient), differences in relative incidence and in burn mechanism in distinct cohorts (by nation and Human Development Index (HDI)) and seasonal trends were analyzed. Furthermore, risk factors for large burns and for (prolonged) inpatient treatment were examined using a multivariate approach.

RESULTS

Temporal resolution shows considerable variation between inpatient and outpatient treatment (p>0.001) and with shorter hospital stays (p=0.004). Swiss citizens and patients with an immigration background from very highly developed countries sustain a significantly lower incidence of heat-related injuries than all others (p<0.001). The most common burn causes among all children, independent of their country of citizenship, are related to kitchen items or hot tea and coffee (35.57%±4.01% resp. 32.39%±5.95%). Logistic regression revealed that migration background from a low HDI country is significantly associated with larger burns (>5% TBSA) and with a need for inpatient treatment.

CONCLUSION

The study emphasizes the need for highly specific measures of burn prevention and indicates the necessity of focusing on certain target groups who are especially vulnerable to burns, such as immigrants from less developed countries.

Genetic influence on scar height and pliability after burn injury in individuals of European ancestry: A prospective cohort study

After similar extent of injury there is considerable variability in scarring between individuals, in part due to genetic factors. This study aimed to identify genetic variants associated with scar height and pliability after burn injury. An exome-wide array association study and gene pathway analysis were performed on a prospective cohort of 665 patients treated for burn injury. Outcomes were scar height (SH) and scar pliability (SP) sub-scores of the modified Vancouver Scar Scale (mVSS). DNA was genotyped using the Infinium^® HumanCoreExome-24 BeadChip. Associations between genetic variants (single nucleotide polymorphisms) and SH and SP were estimated using an additive genetic model adjusting for age, sex, number of surgical procedures and % total body surface area of burn in subjects of European ancestry. No individual genetic variants achieved the cut-off threshold of significance. Gene regions were analysed for spatially correlated single nucleotide polymorphisms and significant regions identified using comb-p software. This gene list was subject to gene pathway analysis to find which biological process terms were over-represented. Using this approach biological processes related to the nervous system and cell adhesion were the predominant gene pathways associated with both SH and SP. This study suggests genes associated with innervation may be important in scar fibrosis. Further studies using similar and larger datasets will be essential to validate these findings.

Efficacy of Topical Enalapril in Treatment of Hypertrophic Scars

BACKGROUND

Angiotensin II activation by angiotensin-converting enzyme (ACE) is a significant mediator in wound healing and collagen production. In this study, the effect of topical application of ACE on hypertrophic scar formation has been studied in a clinical trial.

METHODS

Thirty patients with hypertrophic scar and itching after treatment of 2^nd or 3^rd degree burns participated in this double-blinded clinical trial. Subjects had two same-degree scars on symmetrical sites of body which were randomly allocated into two groups. One side was treated with 1% enalapril ointment and the other side with placebo twice daily. During a 6-months follow-up, a scoring table for itching was completed on a daily basis by patients. Furthermore, a single surgeon measured size of scars once a month. The mean size, thickness and itching score were calculated for each scar and compared between medication and placebo-treated scars.

RESULTS

The mean size of scars in enalapril treated side was significantly less than scars in the placebo side. Additionally, enalapril treated scars had significantly lower itching scores compared to the placebo group.

CONCLUSION

Topical enalapril significantly decreases the clinical parameters of hypertrophic scar and also itching as an indirect indicative of scar improvement. Furthermore, enalapril proved to be clinically safe for patients with low incidence of adverse drug reactions and acceptable cost effectiveness.

Abdominal scar characteristics as a predictor of cervical stenosis after abdominal radical trachelectomy

To investigate whether abdominal scar characteristics could predict the occurrence of cervical stenosis after abdominal radical trachelectomy (ART), we conducted a retrospective study and investigated the relationship between abdominal scar characteristics and the occurrence of cervical stenosis in patients one year after undergoing ART. The abdominal scars were evaluated using the Vancouver Scar Scale (VSS). Seventy-two participants were enrolled in the study, including 15 (20.8%) women with cervical stenosis, and 57 (79.2%) without stenosis. Results showed that the mean abdominal scar score assessed by VSS was higher in patients with cervical stenosis (7, range: 1-10) compared to those without stenosis (4, range: 0-9) (P = 0.001). Incidence rates of cervical stenosis increased with the VSS score. For women with VSS scores of 0 to 4, 5, 6, 7, 8, 9 and 10, respectively, the occurrences of cervical stenosis were 6.1%, 16.7%, 16.7%, 27.3%, 37.5%, 50% and 100%. The cutoff point of VSS score was 7 according to the receiver operating characteristic (ROC) curve. Fourteen of the 15 stenosis happened either in patients without anti-stenosis tools (Foley catheters or tailed intrauterine devices) placed during the surgery or after the devices were removed. Our results demonstrated that VSS is an effective approach to assess the presence of cervical stenosis after ART. Women who have an abdominal scar with a VSS score > 7 have a high risk of developing isthmic stenosis without anti-stenosis tools in place.

Pathophysiologic Mechanisms and Current Treatments for Cutaneous Sequelae of Burn Wounds

Burn injuries are a pervasive clinical problem. Extensive thermal trauma can be life-threatening or result in long-lasting complications, generating a significant impact on quality of life for patients as well as a cost burden to the healthcare system. The importance of addressing global or systemic issues such as resuscitation and management of inhalation injuries is not disputed but is beyond the scope of this review, which focuses on cutaneous pathophysiologic mechanisms for current treatments, both in the acute and long-term settings. Pathophysiological mechanisms of burn progression and wound healing are mediated by highly complex cascades of cellular and biochemical events, which become dysregulated in slow-healing wounds such as burns. Burns can result in fibroproliferative scarring, skin contractures, or chronic wounds that take weeks or months to heal. Burn injuries are highly individualized owing to wound-specific differences such as burn depth and surface area, in addition to patient-specific factors including genetics, immune competency, and age. Other extrinsic complications such as microbial infection can complicate wound healing, resulting in prolonged inflammation and delayed re-epithelialization. Although mortality is decreasing with advancements in burn care, morbidity from postburn deformities continues to be a challenge. Optimizing specialized acute care and late burn outcome intervention on a patient-by-patient basis is critical for successful management of burn wounds and the associated pathological scar outcome. Understanding the fundamentals of integument physiology and the cellular processes involved in wound healing is essential for designing effective treatment strategies for burn wound care as well as development of future therapies. Published 2018. Compr Physiol 8:371-405, 2018.

Fibromodulin reduces scar formation in adult cutaneous wounds by eliciting a fetal-like phenotype

Blocking transforming growth factor (TGF)β1 signal transduction has been a central strategy for scar reduction; however, this approach appears to be minimally effective. Here, we show that fibromodulin (FMOD), a 59-kD small leucine-rich proteoglycan critical for normal collagen fibrillogenesis, significantly reduces scar formation while simultaneously increasing scar strength in both adult rodent models and porcine wounds, which simulate human cutaneous scar repair. Mechanistically, FMOD uncouples pro-migration/contraction cellular signals from pro-fibrotic signaling by selectively enhancing SMAD3-mediated signal transduction, while reducing AP-1-mediated TGFβ1 auto-induction and fibrotic extracellular matrix accumulation. Consequently, FMOD accelerates TGFβ1-responsive adult fibroblast migration, myofibroblast conversion, and function. Furthermore, our findings strongly indicate that, by delicately orchestrating TGFβ1 activities rather than indiscriminately blocking TGFβ1, FMOD elicits fetal-like cellular and molecular phenotypes in adult dermal fibroblasts in vitro and adult cutaneous wounds in vivo, which is a unique response of living system undescribed previously. Taken together, this study illuminates the signal modulating activities of FMOD beyond its structural support functions, and highlights the potential for FMOD-based therapies to be used in cutaneous wound repair.

Sex differences in tendon structure and function

Tendons play a critical role in the transmission of forces between muscles and bones, and chronic tendon injuries and diseases are among the leading causes of musculoskeletal disability. Little is known about sex-based differences in tendon structure and function. Our objective was to evaluate the mechanical properties, biochemical composition, transcriptome, and cellular activity of plantarflexor tendons from 4 month old male and female C57BL/6 mice using in vitro biomechanics, mass spectrometry-based proteomics, genome-wide expression profiling, and cell culture techniques. While the Achilles tendons of male mice were approximately 6% larger than female mice (p < 0.05), the cell density of female mice was around 19% greater than males (p < 0.05). No significant differences in mechanical properties (p > 0.05) of plantaris tendons were observed. Mass spectrometry proteomics analysis revealed no significant difference between sexes in the abundance of major extracellular matrix (ECM) proteins such as collagen types I (p = 0.30) and III (p = 0.68), but female mice had approximately twofold elevations (p < 0.05) in less abundant ECM proteins such as fibronectin, periostin, and tenascin C. The transcriptome of male and female tendons differed by only 1%. In vitro, neither the sex of the serum that fibroblasts were cultured in, nor the sex of the ECM in which they were embedded, had profound effects on the expression of collagen and cell proliferation genes. Our results indicate that while male mice expectedly had larger tendons, male and female tendons have very similar mechanical properties and biochemical composition, with small increases in some ECM proteins and proteoglycans evident in female tendons. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:2117-2126, 2017.

Mini-encyclopaedia of the wound healing - Opportunities for integrating multi-omic approaches into medical practice

Wound healing is a highly complex life-important repair process triggered by plenty of local and/or systemic organ and tissue damaging events, such as an acute surgical invasion, accidental organ and tissue damages, acute and chronic diseases, aggressive local and systemic therapeutic approaches (e.g. irradiation and systemic chemotherapy). Individual health condition determines over the quality of wound healing. Impaired wound healing, in turn, may lead, for example, to post-surgical complications frequently observed in elderly, chronic ulcers in diabetic patients, hindered and ineffective pain management, etc. However, these well-acknowledged examples are just the tip of the iceberg. The entire spectrum of potential consequences is much broader. Therefore, all the aspects of wound healing need to receive a dedicated attention of many specialised medical fields and healthcare as a whole. In contrast, there is still strongly limited knowledge collected regarding the molecular and cellular mechanisms underlying the physiological versus impaired wound healing. The contents of this article might be of great importance for multi-professional considerations as well as for the experts working in specific fields such as clinical proteomics, general practice, laboratory medicine, surgery including plastic surgery and aesthetic medicine, gerontology, psychology, diabetology, endocrinology, oncology, cardiovascular disease, radiology, and healthcare economy.

SIGNIFICANCE

The contents of this article are strongly motivated by the particular value of wound healing quality for medical care and might be of great importance for multi-professional considerations and experts working in specialised fields: predictive and preventive medicine, general practitioners, laboratory medicine, surgery including plastic surgery and aesthetic medicine, gerontology, psychology, diabetology, endocrinology, oncology, cardiovascular disease, radiology, and healthcare economy. The article is aiming at both educational and scientific purposes: on one side it summarises comprehensive information available regarding wound healing mechanisms and molecular pathways involved. On the other side the article provides highly innovative hypotheses for multi-professional considerations relevant for several research fields which may potentially advance medical services in the close future such as clinical proteomics and multi-omics.

Identification of factors predicting scar outcome after burn injury in children: a prospective case-control study

Background

There is a lack of rigorous research investigating the factors that influence scar outcome in children. Improved clinical decision-making to reduce the health burden due to post-burn scarring in children will be guided by evidence on risk factors and risk stratification. This study aimed to examine the association between selected patient, injury and clinical factors and the development of raised scar after burn injury. Novel patient factors were investigated including selected immunological co-morbidities (asthma, eczema and diabetes type 1 and type 2) and skin pigmentation (Fitzpatrick skin type).

Methods

A prospective case-control study was conducted among 186 children who sustained a burn injury in Western Australia. Logistic regression was used to explore the relationship between explanatory variables and a defined outcome measure: scar height measured by a modified Vancouver Scar Scale (mVSS).

Results

The overall correct prediction rate of the model was 80.6%; 80.9% for children with raised scars (>1 mm) and 80.4% for children without raised scars (≤1 mm). After adjustment for other variables, each 1% increase in % total body surface area (%TBSA) of burn increased the odds of raised scar by 15.8% (95% CI = 4.4–28.5%). Raised scar was also predicted by time to healing of longer than 14 days (OR = 11.621; 95% CI = 3.727–36.234) and multiple surgical procedures (OR = 11.521; 1.994–66.566).

Conclusions

Greater burn surface area, time to healing of longer than 14 days, and multiple operations are independently associated with raised scar in children after burn injury. Scar prevention strategies should be targeted to children with these risk factors.

Skin regeneration with all accessory organs following ablation with irreversible electroporation

Skin scar formation is a complex process that results in the formation of dense extracellular matrix (ECM) without normal skin appendages such as hair and glands. The absence of a scarless healing model in adult mammals prevents the development of successful therapies. We show that irreversible electroporation of skin drives its regeneration with all accessory organs in normal adult rats. Pulsed electric fields at 500 V, with 70 μs pulse duration and 1000 pulses delivered at 3 Hz, applied through two electrodes separated by 2 mm lead to massive cell death. However, the ECM architecture of the skin was preserved. Six months after the ablation, the epidermis, sebaceous glands, panniculus carnosus, hair follicles, microvasculature and arrector pili muscle were altogether re-formed in the entire ablated area. These results suggest a key role of the ECM architecture in the differentiation, migration and signalling of cells during scarless wound healing. Copyright © 2016 John Wiley & Sons, Ltd.

A prospective study of time to healing and hypertrophic scarring in paediatric burns: every day counts

BACKGROUND

It is commonly accepted that burns taking longer than 3 weeks to heal have a much higher rate of hypertrophic scarring than those which heal more quickly. However, some of our patients develop hypertrophic scars despite healing within this 3-week period.

METHODS

We performed a prospective study of 383 paediatric burns treated non-operatively at a regional burns centre over a 2-year period from May 2011 to April 2013. Scar assessment was performed by a senior burns therapist using the Vancouver Scar Scale.

RESULTS

Overall rates of hypertrophic scarring were 17.2%. Time to healing was the strongest predictor of developing hypertrophic scarring, and the earliest hypertrophic scar developed in a patient who was healed after 8 days. The risk of hypertrophic scarring was multiplied by 1.138 for every additional day taken for the burn wound to heal. There was a trend towards higher rates of hypertrophic scarring in non-white skin types but this did not reach statistical significance.

CONCLUSIONS

The risk of hypertrophic scarring increases with every day and, therefore, every effort should be made to get the wound healed as quickly as possible, even within the traditional 3-week period usually allowed for healing. We believe that the traditional dogma of aiming for healing within 3 weeks is overly simplistic and should be abandoned: in paediatric burns, every day counts.

TRIAL REGISTRATION

Not applicable.

Increased burn healing time is associated with higher Vancouver Scar Scale score

Increased burn wound healing time has been shown to influence abnormal scarring. This study hypothesised that scar severity increases commensurate to the increase in time to healing (TTH) of the wound. Wound healing and scar data from burn patients treated by the Burn Service of Western Australia at Royal Perth Hospital were examined. The relationship between TTH and scar severity, as assessed by the modified Vancouver Scar Scale (mVSS), was modelled using regression analysis. Interaction terms evaluated the effect of surgery and total body surface area - burn (TBSA) on the main relationship. Maximum likelihood estimation was used to account for potential bias from missing independent variable data. The sample had a median age of 34 years, TTH of 24 days, TBSA of 3% and length of stay of five days, 70% were men and 71% had burn surgery. For each additional day of TTH, the mVSS score increased by 0.11 points (P ≤ 0.001) per day in the first 21 days and 0.02 points per day thereafter (P = 0.004). The relationship remained stable in spite of TBSA or surgical intervention. Investigation of the effect of missing data revealed the primary model underestimated the strength of the association. An increase in TTH within 21 days of injury is associated with an increase in mVSS or reduced scar quality. The results confirm that efforts should be directed toward healing burn wounds as early as possible.

Missense Variant in MAPK Inactivator PTPN5 Is Associated with Decreased Severity of Post-Burn Hypertrophic Scarring

BACKGROUND

Hypertrophic scarring (HTS) is hypothesized to have a genetic mechanism, yet its genetic determinants are largely unknown. The mitogen-activated protein kinase (MAPK) pathways are important mediators of inflammatory signaling, and experimental evidence implicates MAPKs in HTS formation. We hypothesized that single-nucleotide polymorphisms (SNPs) in MAPK-pathway genes would be associated with severity of post-burn HTS.

METHODS

We analyzed data from a prospective-cohort genome-wide association study of post-burn HTS. We included subjects with deep-partial-thickness burns admitted to our center who provided blood for genotyping and had at least one Vancouver Scar Scale (VSS) assessment. After adjusting for HTS risk factors and population stratification, we tested MAPK-pathway gene SNPs for association with the four VSS variables in a joint regression model. In addition to individual-SNP analysis, we performed gene-based association testing.

RESULTS

Our study population consisted of 538 adults (median age 40 years) who were predominantly White (76%) males (71%) admitted to our center from 2007-2014 with small-to-moderate-sized burns (median burn size 6% total body surface area). Of 2,146 SNPs tested, a rare missense variant in the PTPN5 gene (rs56234898; minor allele frequency 1.5%) was significantly associated with decreased severity of post-burn HTS (P = 1.3×10-6). In gene-based analysis, PTPN5 (P = 1.2×10-5) showed a significant association and BDNF (P = 9.5×10-4) a borderline-significant association with HTS severity.

CONCLUSIONS

We report PTPN5 as a novel genetic locus associated with HTS severity. PTPN5 is a MAPK inhibitor expressed in neurons, suggesting a potential role for neurotrophic factors and neuroinflammatory signaling in HTS pathophysiology.

Genome-wide Association Study of Postburn Scarring Identifies a Novel Protective Variant

OBJECTIVE

To identify genetic variants associated with the severity of postburn hypertrophic scarring (HTS) using a genome-wide approach.

BACKGROUND

Risk of severe postburn HTS is known to depend on race, but the genetic determinants of HTS are unknown.

METHODS

We conducted a genome-wide association study (GWAS) in a prospective cohort of adults admitted with deep-partial-thickness burns from 2007 through 2014. Scar severity was assessed over time using the Vancouver Scar Scale (VSS), and DNA was genotyped with a >500,000-marker array. We performed association testing of single-nucleotide polymorphisms (SNPs) with minor allele frequency (MAF) >0.01 using linear regression of VSS height score on genotype adjusted for patient and injury characteristics as well as population genetic structure. Array-wide significance was based on Bonferroni correction for multiple testing.

RESULTS

Of 538 patients (median age 40 years, median burn size 6.0% of body surface area), 71% were men and 76% were White. The mean VSS height score was 1.2 (range: 0-3). Of 289,639 SNPs tested, a variant in the CUB and Sushi multiple domains 1 (CSMD1) gene (rs11136645; MAF = 0.49), was significantly associated with decreased scar height (regression coefficient = -0.23, P = 7.9 × 10).

CONCLUSIONS

In the first published GWAS of HTS, we report that a common intronic variant in the CSMD1 gene is associated with reduced severity of postburn HTS. If this association is confirmed in an independent cohort, investigating the potential role of CSMD1 in wound healing may elucidate HTS pathophysiology.