Hypertrophic scarring and keloids: pathomechanisms and current and emerging treatment strategies

Keloid vasculature reacts to intralesional injection therapies but does not predict the response to treatment: Biopsies from double-blinded, randomized, controlled trial

Keloids are benign fibroproliferative skin scars that expand beyond the original wound site. Hypoxia and angiogenesis are thought to drive pathological scar formation in keloids. We utilized biopsies collected before, during and after the double-blinded randomized controlled trial (RCT) comparing the intralesional treatments of 5-fluorouracil and triamcinolone injections in 48 human keloids. We could not detect any cells expressing the hypoxia markers (carbonic anhydrase 9 and hypoxia-inducible factor 1α) in the three distinct regions of keloid dermis. The amount of epidermal hypoxia could not predict the response to treatment. The middle dermis of the patients obtaining a clinical response to the intralesional injections showed significant increase in mature blood vessels and in lymphatics after the treatment. Our study does not support hypoxia being the driver behind keloid formation but demonstrates that the patients obtaining a response to intralesional therapies develop more blood vessels and lymphatics in the middle dermis of the keloids during the treatment.

LA-peptide Hydrogel-Regulation of macrophage and fibroblast fates and their crosstalk via attenuating TGF-β to promote scarless wound healing

The homeostasis of the wound microenvironment is fundamental for scarless wound healing, while the excessive accumulation of transforming growth factor-beta (TGF-β) in the wound microenvironment always leads to hypertrophic scars (HS) formation by regulating cell fates and crosstalk among various types of cells, such as macrophages and fibroblasts. This study reports that an injectable, self-assembling LA-peptide hydrogel has the potential to facilitate scarless cutaneous wound healing through dynamically adsorbing TGF-β within the wound environment. We found that the released LA peptides led to the suppression of both the PI3K/Akt and TGF-β/Smad2/3 pathways in macrophages and fibroblasts. As expected, the application of LA-peptide hydrogel alleviated the M2 type polarization of macrophages and inhibited fibroblasts activation by adsorbing TGF-β both in vitro and in vivo. Furthermore, designated concentrations of the LA-peptide hydrogel achieved controlled release of LA peptides, enabling dynamic regulation of TGF-β for maintaining microenvironment homeostasis during different phases of wound healing. This contributed to the inhibition of HS formation without delaying wound healing in both a mouse full-thickness skin wound model and a rabbit ear scar model. Overall, the LA-peptide hydrogel provides promising avenues for promoting scarless healing of wounds, exemplifying precision medicine-guided targeting of specific pathogenic molecules, such as TGF-β, and highlighting the significance of dynamic regulation of TGF-β homeostasis in wound microenvironment.

LncRNA PVT1 Promotes the Progress of Hypertrophic Scar via Regulating the Proliferation and Migration of Myofibroblasts Through Targeting miR-29a-3p/STAT3

Purpose

Hypertrophic scar (HS) is a common clinical disease during skin injury recovery. Although medicines have been listed for treatment, none are universally effective, and the details of the underlying molecular regulation are yet to be revealed. This research was aimed at exploring the clinical value of lncRNA PVT1 in HS formation and its potential mechanisms in human hyperplastic scar myofibroblasts (HSFs).

Patients and Methods

Fifty-seven HS patients were enrolled. RT-qPCR was conducted to examine the RNA levels of lncRNA PVT1, miR-29a-3p and STAT3. CCK-8, Transwell, and flow cytometry were used to analyze cell proliferation, migration, and apoptosis. The targeting relationship of PVT1/miR-29a-3p and miR-29a-3p/STAT3 was proved by the dual luciferase reporter.

Results

Relative expression of lncRNA PVT1 in human HS tissues was higher compared with normal tissues. LncRNA PVT1 silencing slowed proliferation and migration and accelerated apoptosis in human HSFs. miR-29a-3p was downregulated in human HS tissues, which was negatively correlated with PVT1 levels. LncRNA PVT1 was covalently bound to miR-29a-3p. miR-29a-3p played an important role in the proliferation, migration, and apoptosis of human HSFs. miR-29a-3p inhibitor rescued the negative influence of lncRNA PVT1 silencing on cells. STAT3 was covalently linked to miR-29a-3p.

Conclusion

LncRNA PVT1 was a potential biomarker for HS and regulated the biological behavior of human HSFs via miR-29a-3p/STAT3.

PAQR4: From spatial regulation of cell signaling to physiological homeostasis and diseases

Progestin and adipoQ receptor family member 4 (PAQR4) gene is a recently discovered seven-transmembrane protein-coding gene that belongs to the PAQR family. An increasing amount of evidence suggests that PAQR4 is upregulated in multiple tumors and participates in tumor progression and chemotherapy resistance via different signaling pathways; PAQR4 regulates cellular ceramide homeostasis by influencing sphingolipid metabolism and glycerol metabolism, and plays a significant role in adipose tissue remodeling. Meanwhile, it is known that the differential expression of PAQR4 is associated with the occurrence of various diseases and is a potential biomarker and therapeutic target. This article conducts a systematic review of the subcellular localization of PAQR4, its topological structure characteristics, and its functions in cancer occurrence, metabolic diseases, and fertility, and provides clues for the future research and translational application of PAQR4.

Association of the skin microbiome with the biomechanical scar properties in patients with burns

BACKGROUND AND OBJECTIVES

Skin microbiome dysbiosis can cause skin barrier dysfunction and stimulate scar property change. Skin barrier disruption post-burn injury leads to an imbalance in skin microbe diversity and distribution. We aimed to examine the changes in the skin microbiome of re-epithelialized burn scars.

MATERIAL AND METHODS

Twenty three patients were enrolled between January 2020 and July 2022. Twenty-six (13 Scar 1, immediately after complete wound healing; and 13 Scar 2, 3 months after complete wound healing) of seventy-eight scar skin samples (39 Scar 1 and 39 scar 2) qualified for analysis. Microbial community analysis was performed. Biomechanical scar properties of each patient and their correlation with skin microbiome were investigated.

RESULTS

The α-diversity of the scarred skin microbiome increased with time (Shannon's index, p = 0.029; Simpson's index, p = 0.009). The linear discriminant analysis effect size results showed that Bacteroides abundance decreased in scars after 3 months, whereas Campylobacter and Cutibacterium abundance increased. Campylobacter and Cutibacterium negatively and positively correlated with the final distensibility gross and biological elasticity, respectively. These results were consistent with the changes in the biomechanical properties of scars.

CONCLUSION

The scar skin microbial communities in patients with burns changed with biomechanical scar properties over time, and specific skin microorganisms correlated with biomechanical scar dynamics at the genus level.

Comparative Evaluation of Postoperative Scarring with Nasolabial Flap Reconstruction Using Silicone Gel Versus Silicone Gel Sheet: Randomized Controlled Trial

Aim

To evaluate and compare the postoperative scarring with nasolabial flap reconstruction using silicone gel versus silicone gel sheet.

Materials and Methods

This was an in vivo comparative study carried out in the Department of Oral and Maxillofacial Surgery. 10 patients who fit into the inclusion criteria were selected. The surgical procedure was carried out as per the standard protocol. The fishbowl method was used to allocate groups, group A where silicone gel application was prescribed and group B where silicone gel sheets were applied. On postoperative day 10, sutures were removed and the modality was advised as per the study protocol. In group A, silicone gel application was prescribed twice daily for 3 months. In group B, silicone gel sheet application was prescribed for 4 hours on day 1, increasing it by 2 hours a day till 1 week and then 24 hourly until 3 months. The patients were evaluated by a second investigator every 2 weeks until 3 months and at the end of 6 months. The healing of scars was evaluated as per the Vancouver Scar Scale.

Results

Silicone gel showed superior results than silicone gel sheet statistically in terms of pigmentation, vascularity, height and pliability (p<0.05).

Conclusion

In our study, we found an appreciable difference in the healing of scars in both groups. Although both methods aid in better healing of nasolabial scars, silicone gel offers better healing and is well tolerated by the patients.

CD147 inhibition reduced fibronectin expression in TGF-β1-induced keloid fibroblasts by targeting Smad2 signaling pathway

BACKGROUND

CD147 is closely involved in the progression of fibrosis and tumor formation in various tissues, however, its role in keloid formation remains unknown. In this study, we investigate the expression of CD147 in keloids and explore its functional roles.

METHODS

CD147 expression in human keloid tissues was assessed using immunohistopathology and western blot analysis. Human keloid fibroblasts (KFs) were cultured and treated with TGF-β1 alone or in combination with the CD147 inhibitor AC-73. Western blot and immunofluorescence were employed to examine CD147 and fibronectin expression levels in KFs post-treatment. Additionally, the effect of CD147 inhibitor on Smad2 phosphorylation and fibronectin protein levels in TGF-β1-induced KFs was evaluated by western blot. Finally, a keloid-bearing nude mouse model was established to investigate the therapeutic effect of AC-73 in vivo.

RESULTS

CD147 expression was significantly higher in keloid tissues compared to normal skin. TGF-β1 treatment upregulated CD147 and fibronectin expressions in cultured KFs. Inhibition of CD147 with AC-73 reduced the expression levels of both CD147 and fibronectin in KFs. Additionally, AC-73 markedly attenuated TGF-β1-induced fibronectin expression and suppressed Smad2 phosphorylation. In the nude mouse model, AC-73 significantly reduced the gross weight of xenotransplanted keloid tissues.

CONCLUSION

These findings suggest that CD147 is closely involved in keloid progression. Inhibition of CD147 downregulates TGF-β1-induced fibronectin expression in KFs by targeting Smad2 signaling pathway. Thus, CD147 may serve as a promising therapeutic target for keloid treatment.

Endothelial Dysfunction in Keloid Formation and Therapeutic Insights

Keloids are benign fibroproliferative tumors that cause significant physical and mental morbidity owing to their disfiguring appearance, chronic symptoms, and resistance to treatment. Although fibroblast hyperproliferation and excessive extracellular matrix deposition have been extensively studied, less attention has been paid to the role of vascular dysregulation and endothelial dysfunction (ED) in keloid pathogenesis. Emerging evidence highlights abnormal angiogenesis, vascular irregularities, and endothelial injury as critical drivers of fibrosis in keloids. This review explores the direct and indirect mechanisms of ED in keloid progression, including endothelial-to-mesenchymal transition, inflammation, immune cell crosstalk, and hypoxia. In addition, various treatment strategies targeting angiogenesis and ED, such as drugs, radiotherapy, hyperbaric oxygen therapy, compression, and laser treatments, are comprehensively reviewed. This review explores keloids through the lens of vasculature and endothelium, emphasizing the critical roles of vascular dysregulation and ED. It aims to provide insights into the mechanisms of keloid formation and serve as a reference for developing future therapeutic strategies.

Deep Learning Approaches for the Classification of Keloid Images in the Context of Malignant and Benign Skin Disorders

Background/Objectives: Misdiagnosing skin disorders leads to the administration of wrong treatments, sometimes with life-impacting consequences. Deep learning algorithms are becoming more and more used for diagnosis. While many skin cancer/lesion image classification studies focus on datasets containing dermatoscopic images and do not include keloid images, in this study, we focus on diagnosing keloid disorders amongst other skin lesions and combine two publicly available datasets containing non-dermatoscopic images: one dataset with keloid images and one with images of other various benign and malignant skin lesions (melanoma, basal cell carcinoma, squamous cell carcinoma, actinic keratosis, seborrheic keratosis, and nevus). Methods: Different Convolution Neural Network (CNN) models are used to classify these disorders as either malignant or benign, to differentiate keloids amongst different benign skin disorders, and furthermore to differentiate keloids among other similar-looking malignant lesions. To this end, we use the transfer learning technique applied to nine different base models: the VGG16, MobileNet, InceptionV3, DenseNet121, EfficientNetB0, Xception, InceptionRNV2, EfficientNetV2L, and NASNetLarge. We explore and compare the results of these models using performance metrics such as accuracy, precision, recall, F1score, and AUC-ROC. Results: We show that the VGG16 model (after fine-tuning) performs the best in classifying keloid images among other benign and malignant skin lesion images, with the following keloid class performance: an accuracy of 0.985, precision of 1.0, recall of 0.857, F1 score of 0.922 and AUC-ROC value of 0.996. VGG16 also has the best overall average performance (over all classes) in terms of the AUC-ROC and the other performance metrics. Using this model, we further attempt to predict the identification of three new non-dermatoscopic anonymised clinical images, classifying them as either malignant, benign, or keloid, and in the process, we identify some issues related to the collection and processing of such images. Finally, we also show that the DenseNet121 model has the best performance when differentiating keloids from other malignant disorders that have similar clinical presentations. Conclusions: The study emphasised the potential use of deep learning algorithms (and their drawbacks), to identify and classify benign skin disorders such as keloids, which are not usually investigated via these approaches (as opposed to cancers), mainly due to lack of available data.

Microneedle drug delivery system based on hyaluronic acid for improving therapeutic efficiency of hypertrophic scars

Hypertrophic scar (HS) is a disease with excessive skin fibrosis and collagen disorder, which is generally caused by abnormal wound repair process after burn and trauma. Although intralesional injection of 5-fluorouracil (5-Fu) has been used in clinical treatment of HS, the patients' compliance of injection treatment is poor. In this study, a double-layer dissolution microneedle (MN) containing asiaticoside (AS) and 5-Fu was designed for the treatment of HS. Biological macromolecules materials affected the formability, drug release, and hardness of MNs. Therefore, several types of biomacromolecules, including hyaluronic acid (HA), chitosan, and sodium alginate, which could be used to prepare MNs, underwent prescription optimization experiments and the optimized MN prescriptions were obtained. In vitro characterization showed that the MN was sufficient to deliver drugs through the skin. Animal in vivo experiments showed that AS and 5-Fu can synergistically treat HS, significantly reduce the abnormal proliferation of fibroblasts and collagen fiber deposition, and down-regulated collagen I (Col I) and transforming growth factor-β1 (TGF-β1) expression. In conclusion, the micro-needle designed in this study has great prospects in the treatment of HS.

Targeting TEAD would be a potential strategy for scarless wound repair: A preliminary study

Despite of decades of efforts, novel approaches are still limited to attenuate or prevent skin scarring. A previous report published in Science demonstrated that inhibition of YAP promotes scarless wound repair by regeneration. Due to the difficult drugability of targeting YAP, we speculated that inhibition of TEAD, a partner molecule of YAP, might exist similar therapeutic potential. Therefore, the aim of the study was to evaluate therapeutical effect of a novel inhibitor of TEAD auto-palmitoylation, VT107, on scar formation in a cutaneous wound healing model. Our findings confirmed VT107 exhibited favorable effect on preventing scarring, manifesting as reducing fibroblast proliferation and collagen denaturation, decreasing TGF-β1 and collagen deposition, as well as connective tissue growth factor (CTGF) expression. These findings provide a novel insight for the development of anti-scarring strategies. TEAD would become an ideal target for the treatment of scars.

Association Between Cesarean Scar and Pelvic Floor Muscle Tone at 6-8 Weeks Postpartum

INTRODUCTION AND HYPOTHESIS

The relationship between cesarean section scars and active pelvic floor muscle tone lacks sufficient evidence. This study is aimed at investigating the relationship between the severity of cesarean section scars and active pelvic floor muscle tone in postpartum women.

METHODS

We conducted a prospective cross-sectional study of 604 women at 6-8 weeks postpartum. Active pelvic floor muscle tone was assessed using the Glazer protocol, and scar severity was categorized as no scar, normal scar, and hypertrophic scar. We collected data on demographic and clinical variables, including age, body mass index (BMI), and comorbidities. Linear regression analysis was employed to assess the association between scar severity and active pelvic floor muscle tone, adjusting for potential confounders.

RESULTS

Compared with the no scar group, the normal scar group exhibited higher levels of active pelvic floor muscle tone (β = 1.68 and 1.47), and the hypertrophic scar group had the highest levels of active pelvic floor muscle tone (β = 5.09 and 5.03). Active pelvic floor muscle tone was significantly higher in women with scars than in those without scars. The association remained significant after adjusting for age, BMI, and comorbidities. Moreover, women with hypertrophic scars exhibited higher active pelvic floor muscle tone than those with normal scars.

CONCLUSIONS

Cesarean section scar severity is positively associated with increased active pelvic floor muscle tone in postpartum women. This finding highlights the importance of scar management and targeted pelvic floor rehabilitation to optimize postpartum recovery.

Individualized surgical treatment using decellularized fish skin transplantation after enzymatic debridement: A two years retrospective analysis

Over the past few years, treatment of burn injuries has evolved beyond primary surgical therapy with the development of enzymatic debridement and new types of skin replacement materials by providing complex personalized therapy concepts aimed at preserving and replacing the dermal layer of the skin. The aim of our study was to develop an individualized treatment algorithm for mixed depth burn wound and evaluate the outcomes of individualized combined treatment of mixed depth burn wounds with enzymatic debridement and decellularized fish skin. A total of 18 patients with a mean age of 34.8 years and mean follow-up of 447.6 days were included. The mean total burn surface area was 12.3%. All patients received enzymatic debridement and an average area of 247.2 cm2 of decellularized fish skin. Days until complete epithelization were 49.4 ± 25.79 days. No patient developed scar contracture or keloid. The Patient and Observer Scar Assessment Scale (POSAS) observer scale showed an overall impression average of 2.2 ± 0.83. The POSAS patient scale showed an overall impression average 2 ± 0.7. The Vancouver Scar Scale showed an average score of 1.89 ± 1.45. In conclusion, combined treatment using enzymatic debridement and decellularized fish skin, polylactide membrane, or split skin grafts allows for a more individualized therapy for mixed depth burn wounds. Fish skin was found to provide a satisfying result in terms of the overall outcome of the developed scar tissue and could lead to a reduction in the area that requires autologous transplantation.

Causal Association Between Inflammatory Factors and Hypertrophic Scar: A Two-Sample Mendelian Randomization Study

BACKGROUND

Hypertrophic scars result from abnormal healing following skin injuries.

AIM

To delve deeper into the causal association between inflammatory factors and hypertrophic scars.

METHODS

This study utilized genetic data from the FINN cohort and pertinent literature to scrutinize the nexus between a spectrum of inflammatory factors-encompassing IL-1β, interleukin 1 receptor-like 1, MCP1, RANTES/CCL5, TNFα, IL-8, IL-18, and CTACK/CCL27-and the risk of hypertrophic scarring. Our analytical strategy was based on the inverse variance weighted (IVW) approach, further bolstered by MR-Egger, weighted median, and weighted mode methods to ensure a comprehensive assessment. The reliability of our findings was rigorously appraised through Cochran's Q test, MR-Egger regression, MR-PRESSO, and leave-one-out analysis.

RESULTS

The genetic prediction results revealed a significant association between CTACK and hypertrophic scars (OR 1.21, 95% CI 1.05-1.4, p = 0.01) using the IVW method, although it was not corroborated by other MR analysis methods. The remaining inflammatory factors did not exhibit significant correlations with the risk of hypertrophic scar formation (all p > 0.05). The absence of significant heterogeneity among the IVs was indicated by Cochran's Q test. MR-Egger and MR-PRESSO analyses collectively suggested no substantial horizontal pleiotropy influencing the results, except for the relationship between RANTES and hypertrophic scars. Upon exclusion of an outlier, the causal relationship between RANTES and hypertrophic scars was found to be non-significant.

CONCLUSION

Our MR analysis supports a causal association between CTACK and hypertrophic scars, enhancing our understanding of scar formation and suggesting potential targeted therapeutic strategies for treatment.

Scoping review for pain mitigation during intralesional injections of corticosteroid for hypertrophic scar and keloid treatment

BACKGROUND

Intralesional corticosteroid injection (ILCSI) has been proven to successfully treat hypertrophic scars (HTSs) and keloids and attain remission in 50% of keloids. Pain is a significant problem with ILCSI, which can affect treatment compliance and effectiveness. To date, many techniques involving ILCSI have been described and used to achieve scar treatment while reducing side effects. The injection technique remains the most widely available method in many healthcare centres.

OBJECTIVE

This scoping review explores strategies for alleviating pain while administering ILCSIs for hypertrophic scarring and keloid management. ILCSI is a second-line treatment for HTSs and a first-line treatment for keloids.

ELIGIBILITY CRITERIA

This scoping review included studies where HTSs and keloids were treated with ILCSI and considered diverse demographics and injection methods. This review excludes other methods of corticosteroid drug delivery where injection is not involved and where the pain assessed is unrelated to injection or infiltration of the scar.

SOURCES OF EVIDENCE

This review systematically searched critical databases from inception to December 2023, including ScienceDirect, PubMed and Web of Science, and handpicked articles traced from available review papers. Only English-language publications focused on pain management during ILCSIs for HTSs and keloids were included. All levels of scientific evidence were considered. An in-depth evaluation of the injection technique, type of analgesia or anaesthesia administered, effectiveness of pain management and overall treatment outcomes was conducted.

CHARTING METHODS

Citations were compiled in an Excel spreadsheet, with three authors screening the titles and abstracts based on inclusion criteria. Decisions were finalised collaboratively, exclusions were documented and results were presented using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses flow diagram.

RESULTS

16 prospective studies, 2 retrospective studies, 1 case study and 15 journal articles were included. These studies examined ILCSI for hypertrophic scarring and keloid treatment. No differences in pain intensity between HTSs and keloids were reported. 11 studies systematically explored pain reduction methods such as topical analgesia, cryoanaesthesia, mixing triamcinolone acetonide with local analgesics, slow infiltration techniques, vibration analgesia and needle-free injectors.

CONCLUSION

Pain can significantly impact patient compliance and treatment outcomes. This review offers a foundational reference for healthcare providers and researchers in the field of scar management, providing insights into current practices and highlighting areas for future research and development.

Unveiling the Link: The Potential Roles of Vitamin D in Keloid Pathophysiology

Keloid disease, a fibroproliferative skin disorder, is characterised by scar tissue growth that extends beyond the original wound boundaries. Despite advancements, current treatments, particularly surgical excision, often result in high recurrence rates, ranging from 45% to 100%. Recent investigations into the role of vitamin D (vit D) in keloids present a promising avenue for novel therapeutic strategies. Studies have highlighted the multifaceted involvement of vit D, including its immunomodulatory effects and influence on key processes such as fibroblast activity, collagen production and extracellular matrix dynamics. Additionally, emerging research has explored the potential impact of vit D on epithelial-to-mesenchymal transition and endothelial dysfunction, both of which are implicated in keloid formation and progression. This review consolidates the current evidence linking vitamin D deficiency to keloid pathogenesis, shedding light on potential mechanisms and therapeutic targets. By elucidating the intricate interplay between vit D signalling and keloid development, this study paves the way for innovative treatment approaches that may enhance patient outcomes and mitigate the burden of this challenging dermatological condition.

Younger age correlates with increased gutter impingement rates after total ankle arthroplasty

BACKGROUND

While total ankle arthroplasty (TAA) has evolved over the years with improved designs and enhanced bony fixation methods, it remains a technically demanding procedure with a risk of early postoperative complications. One of the most common complications associated with TAA is medial and lateral gutter ankle impingement, which can lead to issues such as increased pain and decreased range of motion (ROM). However, there is a paucity of information in the literature discussing the impact of certain risk factors on gutter impingement complications.

METHODS

A retrospective analysis was conducted on a cohort of patients who underwent a TAA at a single institution from 2003 to 2019 with a minimum of 2-year follow-up. Patient were identified as having gutter impingement based on diagnostic imaging and/or clinical examination. Data collection included demographics, implant type, follow-up time, and co-morbidities. Multivariate odds ratios (OR) of experiencing gutter impingement were calculated for perioperative variables.

RESULTS

The study included a total of 908 patients who underwent TAA with a minimum of 2 year follow up and 121 patients (13.3 %) who subsequently experienced gutter impingement. The average follow-up time was 5.84 + /- 3.07 years. There were 178 patients under 55 years old, 495 patients aged 55 to 70, and 235 patients over 70 years old. A higher rate of gutter impingement was observed in patients under 55 years of age compared to those aged 55 to 70 and over 70 (20.8 % vs. 13.5 % vs. 7.2 %; p < 0.01). Multivariable logistic regression revealed that patient age was significantly correlated with gutter impingement following TAA, with an OR of 0.94 (CI: 0.91-0.98; p < 0.01).

CONCLUSION

This study demonstrated increased incidence of gutter impingement in younger patients who underwent TAA. Propensity for scar tissue formation may be higher in this population. Scar tissue deposition following TAA can cause narrowing of the medial and lateral clear spaces, potentially leading to gutter impingement. Additionally, younger patients may have increased activity demands, which subsequently may cause higher rates of symptomatic impingement. As increased impingement after TAA may require the need for additional debridement surgeries, it is important to understand the intricate relationship between age and gutter impingement for managing patient expectations following TAA.

LEVEL OF EVIDENCE

Level III.

The Pathophysiology and Management of Pathologic Scarring-a Contemporary Review

Significance: Pathologic scarring occurs secondary to imbalances in the cellular mechanisms of wound healing and affects millions of people annually. This review article aims to provide a concise overview of the pathophysiology and management of pathologic scarring for clinicians and scientists alike. Recent Advances: Contemporary research in the field has identified aberrations in transforming growth factor-β/small mothers against decapentaplegic (TGF-β/SMAD) signaling pathways as key drivers of pathologic scar formation; indeed, this pathway is targeted by many treatment modalities and translational investigations currently underway. Although intralesional injection of corticosteroids has been the gold standard in the treatment of pathologic scarring, studies show greater treatment efficacy with the use of combination injections such as triamcinolone/5-fluorouracil and triamcinolone/botulinum toxin. Adjunctive therapies including ablative fractional carbon dioxide/erbium-doped yttrium aluminum garnet and non-ablative pulsed-dye lasers, microneedling, and carboxytherapy have shown encouraging results in small cohort studies. Translational investigations involving the use of nanogels, RNA interference, and small molecules targeting TGF-β/SMAD pathways are also currently underway and hold promise for the future. Critical Issues: The heterogeneous nature of hypertrophic scars and keloids poses significant challenges in formulating standardized treatment and assessment protocols, thereby limiting the conclusions that can be drawn. Future Directions: Rigorous clinical trials into the individual and synergistic effects of these therapies would be ideal before any definitive conclusions or evidence-based treatment recommendations can be made. Owing to the heterogeneity of the pathology and patient population, well-conducted cohort studies may be the next best option.

Isotonic medium treatment limits burn wound microbial colonisation and improves tissue repair

Burn injuries undergo a complex healing process in which progressive spreading of epithelial damage can lead to secondary complications such as wound infection, which is a major driver of mortality among burn patients. We recently reported that burning larval zebrafish triggers dysregulated keratinocyte dynamics compared to mechanical injury. Here, we investigate keratinocyte behaviour following burn injury and the subsequent potential for microbial colonisation of burn wounds over time. Real-time imaging, coupled with tracking of photoconverted cells, revealed that early keratinocyte motility contributes to the spread of epithelial damage beyond the initial site of burn injury and that increased epithelial damage was associated with wound colonisation by the fungal pathogen Candida albicans. Modulating osmotic balance by treating larval zebrafish with isotonic medium limited the spread of epithelial damage and reduced microbial colonisation of burn wounds. Using cultured human skin, we found that topical treatment with isotonic solution (saline) similarly prevented the spread of epithelial damage over time. These findings indicate that keratinocyte behaviour contributes to burn wound progression in larval zebrafish and links keratinocyte dynamics to microbial colonisation of burn wounded tissue.

Something Old and Something New-A Pilot Study of Shrinkage and Modern Imaging Devices

Shrinkage, a heat-induced process, reorganizes collagen fibers, thereby reducing wound surface area. This technique, commonly applied in surgeries like periareolar mastopexy and skin grafting, is well-established. Despite its widespread use, modern imaging has recently enabled detailed observation of shrinkage's effects on tissue temperature and oxygenation. The aim of this study is to investigate the effects of shrinkage on histological level, temperature, and tissue oxygenation. Skin flaps were collected, marked, and subjected to shrinkage in vitro, with wound dimensions recorded before and after shrinkage. Biopsy samples were analyzed histologically. In our clinical set up, Snapshot NIR® and FLIR thermography were used to assess tissue oxygenation and temperature changes before and after shrinkage. Shrinkage significantly reduced wound area by almost 47% ± 8.5%, with a 16.5% ± 6.0% reduction in length and a 36.5% ± 7.7% reduction in width. Tissue temperature rose by an average of 38.3 °C post-shrinkage, reaching approximately 65 °C. A slight decrease in oxygen saturation was observed following shrinkage. Histological analyses reveal collagen fiber denaturation and structural reorganization. Thermal shrinkage is an effective method for reducing wound size and tension, demonstrating potential for facilitating larger full-thickness skin grafts. Although minor decreases in oxygenation were observed, shrinkage may enhance wound healing by reducing tension at wound edges. Further studies are needed to quantify its impact on functional and cosmetic outcomes.

Association between pathological scar and hypertension: A two-sample Mendelian randomization study

Observational studies have linked pathological scars to hypertension; however, the causality remains ambiguous. In this study, we aimed to explore this issue using Mendelian randomization (MR). We obtained genome-wide association study data for hypertrophic scar and hypertension from the IEU Open genome-wide association study project [hypertension (containing 9851,867 SNPs, observation group of 124,227, and control group of 337,653), hypertrophic scars (containing 16,380,443 SNPs with a sample mass of 207,482), and keloids (containing 24,197,210 SNPs and sample volume of 481,912)]. The inverse variance weighted method and MR-Egger test were used, followed by a sensitivity analysis. With hypertension as the exposure and hypertrophic scar as the outcome, we obtained the IVW analysis results (OR = 0.264, 95% CI = 0.098-0.709, P = .008) and the MR-Egger test results (OR = 0.036, 95% CI = 0.002-0.544, P = .017); for keloid as the outcome, the results of IVW analysis showed OR = 0.592, 95% CI = 0.293-1.195, P = .143. Contrary to the findings of observational studies, our results revealed hypertension as a protective factor against hypertrophic scarring, and was unrelated to keloids.

Single cell transcriptomics reveals the cellular heterogeneity of keloids and the mechanism of their aggressiveness

Keloid is a dermatofibrotic disease known for its aggressive nature and characterized by pathological scarring, which often leads to disfigurement and frequent recurrences. Effective therapies for keloids are still limited, presumably due to the inadequate comprehension of their aggressive mechanisms. In our study, we examined the unique scenario where both keloid and non-aggressive pathological scar originate from the same patient, providing a rare opportunity to explore the aggressive mechanisms of keloids through single-cell RNA sequencing. We found that the dominant fibroblast subgroup in keloids is mechanoresponsive group, which showed enhanced mechanotransduction and migration. This mechanoresponsive fibroblast subgroup is likely to be the key cell population and confer aggressive growth of keloids. The results also indicate that the endothelial cells and keratinocytes in keloid involve in endothelial-mesenchymal and epithelial-mesenchymal transitions. This study demonstrated the mechanoresponsive fibroblasts and multiple cellular mesenchymal processes could pave the way for further investigations into the keloid aggressiveness.

Effects of Cell-Free Fat Extract and Platelet-Rich Fibrin on Scar Maturation in an Experimental Rabbit Ear Wound Model

Background

Multiple methods have been used to treat hypertrophic scarring; however, an optimal treatment method remains to be established. We aimed to research and compare the effects of cell-free fat extract (CEFFE) and platelet-rich fibrin (PRF) on hypertrophic scar formation based on histomorphological analysis in this study.

Methods

Twelve rabbits were divided into four groups randomly. (CEFFE+PRF group, n=3; CEFFE group, n=3, PRF group, n=3 and Control group, n=3). After the ear hypertrophic scar model were established, the two ears of each rabbit in the four groups were injected with CEFFE 0.05 mL/cm2 + PRF 0.05 mL/cm2, CEFFE 0.1 mL/cm2, PRF 0.1 mL/cm2, and saline 0.1 mL/cm2, respectively. The scar elevation index and histological analysis using hematoxylin-eosin and Masson staining were evaluated after injection on day 40.

Results

The CEFFE+PRF group was significantly more effective in the prevention of pathological scar formation than the CEFFE-only, PRF-only, and control groups in terms of capillary count, collagen organization, fibroblast count, and scar elevation index (p<0.05).

Discussion

CEFFE combined with PRF was the most effective treatment for the prevention of hypertrophic scar formation in our study.

The Endo-lift Laser (Intralesional 1470 nm Diode Laser) for Dermatological Aesthetic Conditions: A Systematic Review

BACKGROUND

The prominence of minimally invasive aesthetic approaches has become increasingly pivotal. The endo-lift laser method is an intralesional 1470 nm diode laser connected to a fiber that serves both therapeutic and aesthetic properties. We sought to evaluate the efficacy and safety of the endo-lift laser method for dermatological aesthetic applications.

METHODS

PubMed, Ovid-Embase, and Web of Science were systematically searched up to November 5th, 2023. A citation search was also performed. The National Institute of Health (NIH) Quality Assessment Tool was used to evaluate the quality of the studies.

RESULTS

Out of 339 articles, twenty-three relevant studies were included in the current review. Applying the endo-lift laser method for rejuvenation, including face and neck lifting, enhancing skin laxity, and disappearing wrinkles, folds, and lines, demonstrated favorable efficacy and safety profile. Moreover, most studies have shown that the endo-lift laser method is promising in eliminating the adipose tissue in the jowl, abdomen, thighs, and arms. The endo-lift laser technique was also efficacious in nose remodeling and blepharoplastic procedures, including treating eyelid and eyebrow ptosis, eye bag, eyebrow position, and eyelid laxity. Patients who suffer from several diseases, such as hidradenitis suppurativa, progressive lipodystrophy, acne vulgaris, scars, and keloids, benefit from procedural treatment with the endo-lift laser technique. Across all studies, the adverse events were mild and self-limiting. Investigating the endo-lift laser method in all aesthetic and therapeutic indications resulted in high patient satisfaction rates.

CONCLUSION

The endo-lift laser technique has therapeutic effects and is recommended for various dermatological aesthetic indications. Further clinical studies with control groups and larger sample sizes are needed to acquire more reliable evidence.

LEVELS OF EVIDENCE III AND IV

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Emerging biomedical technologies for scarless wound healing

Complete wound healing without scar formation has attracted increasing attention, prompting the development of various strategies to address this challenge. In clinical settings, there is a growing preference for emerging biomedical technologies that effectively manage fibrosis following skin injury, as they provide high efficacy, cost-effectiveness, and minimal side effects compared to invasive and costly surgical techniques. This review gives an overview of the latest developments in advanced biomedical technologies for scarless wound management. We first introduce the wound healing process and key mechanisms involved in scar formation. Subsequently, we explore common strategies for wound treatment, including their fabrication methods, superior performance and the latest research developments in this field. We then shift our focus to emerging biomedical technologies for scarless wound healing, detailing the mechanism of action, unique properties, and advanced practical applications of various biomedical technology-based therapies, such as cell therapy, drug therapy, biomaterial therapy, and synergistic therapy. Finally, we critically assess the shortcomings and potential applications of these biomedical technologies and therapeutic methods in the realm of scar treatment.

Exosomal miR‑194 from adipose‑derived stem cells impedes hypertrophic scar formation through targeting TGF‑β1

Hypertrophic scars, which result from aberrant fibrosis and disorganized collagen synthesis by skin fibroblasts, emerge due to disrupted wound healing processes. These scars present significant psychosocial and functional challenges to affected individuals. The current treatment limitations largely arise from an incomplete understanding of the underlying mechanisms of hypertrophic scar development. Recent studies, however, have shed light on the potential of exosomal non‑coding RNAs interventions to mitigate hypertrophic scar proliferation. The present study assessed the impact of exosomes derived from adipose‑derived stem cells (ADSCs‑Exos) on hypertrophic scar formation using a rabbit ear model. It employed hematoxylin and eosin staining, Masson's trichrome staining and immunohistochemical staining techniques to track scar progression. The comprehensive analysis of the present study encompassed the differential expression of non‑coding RNAs, enrichment analyses of functional pathways, protein‑protein interaction studies and micro (mi)RNA‑mRNA interaction investigations. The results revealed a marked alteration in the expression levels of long non‑coding RNAs and miRNAs following ADSCs‑Exos treatment, with little changes observed in circular RNAs. Notably, miRNA (miR)‑194 emerged as a critical regulator within the signaling pathways that govern hypertrophic scar formation. Dual‑luciferase assays indicated a significant reduction in the promoter activity of TGF‑β1 following miR‑194 overexpression. Reverse transcription‑quantitative PCR and immunoblotting assays further validated the decrease in TGF‑β1 expression in the treated samples. In addition, the treatment resulted in diminished levels of inflammatory markers IL‑1β, TNF‑α and IL‑10. In vivo evidence strongly supported the role of miR‑194 in attenuating hypertrophic scar formation through the suppression of TGF‑β1. The present study endorsed the strategic use of ADSCs‑Exos, particularly through miR‑194 modulation, as an effective strategy for reducing scar formation and lowering pro‑inflammatory and fibrotic indicators such as TGF‑β1. Therefore, the present study advocated the targeted application of ADSCs‑Exos, with an emphasis on miR‑194 modulation, as a promising approach to managing proliferative scarring.

Claes K, Blondeel P, Monstrey S, Dorpe JV, Van Vlierberghe S. Photo-crosslinkable polyester microneedles as sustained drug release systems toward hypertrophic scar treatment

Burn injuries can result in a significant inflammatory response, often leading to hypertrophic scarring (HTS). Local drug therapies e.g. corticoid injections are advised to treat HTS, although they are invasive, operator-dependent, extremely painful and do not permit extended drug release. Polymer-based microneedle (MN) arrays can offer a viable alternative to standard care, while allowing for direct, painless dermal drug delivery with tailorable drug release profile. In the current study, we synthesized photo-crosslinkable, acrylate-endcapped urethane-based poly(ε-caprolactone) (AUP-PCL) toward the fabrication of MNs. Physico-chemical characterization (1H-NMR, evaluation of swelling, gel fraction) of the developed polymer was performed and confirmed successful acrylation of PCL-diol. Subsequently, AUP-PCL, and commercially available PCL-based microneedle arrays were fabricated for comparative evaluation of the constructs. Hydrocortisone was chosen as model drug. To enhance the drug release efficiency of the MNs, Brij®35, a nonionic surfactant was exploited. The thermal properties of the MNs were evaluated via differential scanning calorimetry. Compression testing of the arrays confirmed that the MNs stay intact upon applying a load of 7 N, which correlates to the standard dermal insertion force of MNs. The drug release profile of the arrays was evaluated, suggesting that the developed PCL arrays can offer efficient drug delivery for up to two days, while the AUP-PCL arrays can provide a release up to three weeks. Finally, the insertion of MN arrays into skin samples was performed, followed by histological analysis demonstrating the AUP-PCL MNs outperforming the PCL arrays upon providing pyramidical-shaped perforations through the epidermal layer of the skin.

Assessment of Treatment Modalities in Patients With Keloids: A Vancouver Scale Comparison

BACKGROUND

Various treatment modalities are used to treat keloids. However, a comprehensive assessment comparing the effectiveness of these modalities in terms of patient-reported outcomes is warranted.

OBJECTIVE

To assess and compare the effectiveness of various treatment modalities for keloids.

METHODS

We assessed treatment outcomes in a cohort of 250 patients diagnosed with keloids. The patients were categorized into four treatment groups: triamcinolone acetonide (TA), TA + cryotherapy, TA + pulsed dye laser (PDL), and TA + cryotherapy + PDL. The Vancouver Scar Scale was used to evaluate the keloid severity before and after treatment.

RESULTS

Significant differences were noted in the Vancouver Scale scores among the treatment groups (p=0.023). Notably, the TA + cryotherapy + PDL group exhibited the most substantial improvement in the Vancouver Scale scores, whereas the TA + PDL group showed the least difference. Pliability was the most significantly improved in the TA + cryotherapy + PDL group (p=0.039). Male patients experienced a greater reduction in pigmentation scores than female patients (p=0.037).

CONCLUSION

Our findings highlight the effectiveness of combined therapies, particularly TA + cryotherapy + PDL, in improving keloid-related parameters. These results offer valuable insights for clinicians in tailoring keloid treatment strategies and support the implementation of combination therapies for enhanced outcomes. This study underscores the importance of comprehensively assessing treatment modalities for keloid management. Combination therapies such as TA + cryotherapy + PDL irradiation have demonstrated significant promise in improving keloid characteristics.

The Potential of Chat-Based Artificial Intelligence Models in Differentiating Between Keloid and Hypertrophic Scars: A Pilot Study

BACKGROUND

Lasting scars such as keloids and hypertrophic scars adversely affect a patient's quality of life. However, these scars are frequently underdiagnosed because of the complexity of the current diagnostic criteria and classification systems. This study aimed to explore the application of Large Language Models (LLMs) such as ChatGPT in diagnosing scar conditions and to propose a more accessible and straightforward diagnostic approach.

METHODS

In this study, five artificial intelligence (AI) chatbots, including ChatGPT-4 (GPT-4), Bing Chat (Precise, Balanced, and Creative modes), and Bard, were evaluated for their ability to interpret clinical scar images using a standardized set of prompts. Thirty mock images of various scar types were analyzed, and each chatbot was queried five times to assess the diagnostic accuracy.

RESULTS

GPT-4 had a significantly higher accuracy rate in diagnosing scars than Bing Chat. The overall accuracy rates of GPT-4 and Bing Chat were 36.0% and 22.0%, respectively (P = 0.027), with GPT-4 showing better performance in terms of specificity for keloids (0.6 vs. 0.006) and hypertrophic scars (0.72 vs. 0.0) than Bing Chat.

CONCLUSIONS

Although currently available LLMs show potential for use in scar diagnostics, the current technology is still under development and is not yet sufficient for clinical application standards, highlighting the need for further advancements in AI for more accurate medical diagnostics.

LEVEL OF EVIDENCE IV

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online instructions to authors www.springer.com/00266 .

Sele-targeted siRNA liposome nanoparticles inhibit pathological scars formation via blocking the cross-talk between monocyte and endothelial cells: a preclinical study based on a novel mice scar model

BACKGROUND

Pathological scars (PS) are one of the most common complications in patients with trauma and burns, leading to functional impairments and aesthetic concerns. Mechanical tension at injury sites is a crucial factor in PS formation. However, the precise mechanisms remain unclear due to the lack of reliable animal models.

RESULTS

We developed a novel mouse model, the Retroflex Scar Model (RSM), which induces PS by applying controlled tension to wounds in vivo. RNA sequencing identified significant transcriptome changes in RSM-induced scars. Elevated expression of E-Selectin (Sele) was observed in endothelial cells from both the RSM model and human PS (Keloid) samples. In vitro studies demonstrated that cyclic mechanical stretching (CMS) increased Sele expression, promoting monocyte adhesion and the release of pro-inflammatory factors. Single-cell sequencing analysis from the GEO database, complemented by Western blotting, immunofluorescence, and co-immunoprecipitation, confirmed the role of Sele-mediated monocyte adhesion in PS formation. Additionally, we developed Sele-targeted siRNA liposome nanoparticles (LNPs) to inhibit monocyte adhesion. Intradermal administration of these LNPs effectively reduced PS formation in both in vivo and in vitro studies.

CONCLUSIONS

This study successfully established a reliable mouse model for PS, highlighting the significant roles of mechanical tension and chronic inflammation in PS formation. We identified Sele as a key therapeutic target and developed Sele-targeted siRNA LNPs, which demonstrated potential as a preventive strategy for PS. These findings provide valuable insights into PS pathogenesis and open new avenues for developing effective treatments for pathological scars.

Oregano essential oil-infused mucin microneedle patch for the treatment of hypertrophic scar

Hypertrophic scar (HS) manifests as abnormal dermal myofibroblast proliferation and excessive collagen deposition, leading to raised scars and significant physical, psychological, and financial burdens for patients. HS is difficult to cure in the clinic and current therapies lead to recurrence, pain, and side effects. In this study, a natural amphiphilic polymer mucin is used to prepare a dissolving microneedle (muMN) that is loaded with oregano essential oil (OEO) for HS therapy. muMN exhibits sufficient skin/scar tissue penetration, quick skin recovery time after removal, good loading of natural essential oil, fast dissolution and detachment from the base layer, and good biocompatibility to applied skin. In the rabbit HS model, OEO@muMN shows a significant reduction in scar thickness, epidermal thickness index, and scar elevation index. OEO@muMN also attenuates the mean collagen area fraction and decreases the number of capillaries in scar tissues. Biochemical Assay reveals that OEO@muMN significantly inhibits the expression of transforming growth factor-β1 (TGF-β1) and hydroxyproline (HYP). In summary, this study demonstrates the feasibility and good efficacy of using the anti-proliferative and anti-oxidative OEO for HS treatment. OEO@muMN is an efficient formulation that holds the potential for clinical anti-HS application. muMN is an efficient platform to load and apply essential oils transdermally.

The Role of Biomechanical Forces in the Formation and Treatment of Pathological Scars

Pathological scars, including hypertrophic scar and keloid are the result of excessive tissue repair and are influenced by biomechanical forces like tension, mechanical pressure, and stiffness. These forces significantly impact scar development and progression, affecting wound healing, collagen deposition, and tissue remodeling. Understanding how these mechanical stimuli contribute to scar development is essential for devising effective therapeutic interventions. Clinically, reducing wound tension and applying mechanical pressure are key strategies for managing pathological scars. Techniques like super-tension-reduction suturing, stress-shielding polymers, and force-modulating tissue bridges (FMTB) have been shown to effectively alleviate tension and reduce scar proliferation. Additionally, Pressure Garment Therapy (PGT) is widely used to treat hypertrophic scars by reducing tissue stiffness, limiting collagen buildup, and promoting collagen realignment. Despite challenges such as discomfort and uneven pressure application, ongoing research focuses on enhancing these therapies through mechanosensitive technologies to improve both efficacy and patient comfort. This review highlights the role of biomechanical forces in scar formation and discusses therapeutic approaches that target these forces to improve clinical outcomes.

Assessing Scar Outcomes Using Objective Scar Measurement Tools: An Adjunct to Validated Scar Evaluation Scales

BACKGROUND

The assessment of scar outcomes is important to both patient care and research focused on understanding the results of medical and surgical interventions. The Vancouver Scar Scale (VSS) and Patient and Observer Scar Assessment Scale (POSAS) are validated and simple instruments to assess scars. However, these subjective scales have shortcomings. The VSS fails to capture patient perception and has indeterminate validity and reliability. The POSAS captures patient perception, but the observer scale has been shown to have moderate amounts of interrater variability. Studies highlighting the ability of objective scar assessment tools to produce reliable and reproducible results are needed. In this study, the authors aimed to validate the use of the FibroMeter, ElastiMeter, and SkinColorCatch as objective adjuncts in the assessment of hypertrophic scar and keloid outcomes.

METHODS

In this prospective single-center study, scars were assessed using the VSS, the POSAS, and the objective study tools (FibroMeter, ElastiMeter, and SkinColorCatch). Correlations between the different methods of scar assessment were measured.

RESULTS

The FibroMeter and SkinColorCatch showed significant correlations with the VSS total and the observer POSAS total. The ElastiMeter showed significant correlations with both the patient and observer POSAS totals. Unexpected correlations between ElastiMeter measurements and the vascularity or pigmentation of scars indicate that scoring of these categories may be influenced by how severe the scar looks to the observer subjectively, underscoring the need for reliable objective scar assessment tools.

CONCLUSION

The results highlight the ability of the FibroMeter, ElastiMeter, and SkinColorCatch to assess scars, and demonstrate their potential in serving as important adjuncts to previously validated scar assessment scales.

Construction of ceRNA Network and Disease Diagnosis Model for Keloid Based on Tumor Suppressor ERRFI1

The aim of this study is to identify the key biomarker of keloid (KD) with significant diagnostic value and to construct the related competing endogenous RNA (ceRNA) network and disease diagnostic model to provide new ideas for the early diagnosis and prevention of KD. Public databases were used to identify the key gene of KD. Enrichment analysis and immune cell infiltration (ICI) analysis revealed its functional and immune characteristics. Then, a ceRNA network was constructed to explore the potential pathways of it. Random forest (RF) analysis was applied to construct a predictive model for the disease diagnosis of KD. Finally, immunohistochemistry (IHC) and RT-qPCR were used to verify the differential expression of key gene. ERRFI1 was identified as a key biomarker in KD and was lowly expressed in KD. The ceRNA network revealed that H0TAIRM1-has-miR-148a-3p-ERRFI1 may be a potential pathway in KD. Finally, a 2-gene diagnostic prediction model (ERRFI1, HSD3B7) was constructed and externally validated and the results suggested that the model had good diagnostic performance. ERRFI1 is a downregulated gene in KD and is expected to be a promising predictive marker and disease diagnostic gene. ICI may play a role in the progression of KD. The ceRNA network may provide new clues to the potential pathogenesis of KD. Finally, the new KD diagnostic model could be an effective tool for assessing the risk of KD development.

Safety and efficacy of intralesional bleomycin for keloids and hypertrophic scars: A systematic review and meta-analysis

BACKGROUND

Bleomycin, originally an antitumor drug, was explored as a pathological scar treatment in the mid-1990s. However, its efficacy and safety profile varies among individuals.

AIMS

This study aimed to assess topical bleomycin's efficacy and safety in treating hypertrophic scars and keloids.

METHODS

We reviewed randomized controlled trials (RCTs) and controlled clinical trials (CCTs) published in English, comparing intralesional bleomycin to placebos or common intralesional scar treatments. Primary outcomes included percentage change in scar improvement, pigmentation, recurrence, atrophy, pain, telangiectasia, ulceration, patient self-assessment, and observer assessment (>50%).

RESULTS

Six trials met the criteria. Bleomycin significantly improved scar reduction compared to triamcinolone (p < 0.05). There was no significant difference in pigmentation (p = 0.05) and recurrence (p = 0.21) compared to other treatments. In terms of safety, bleomycin caused less skin atrophy (p < 0.01) and telangiectasia (p < 0.01) but more pain (p = 0.03) than other treatments.

CONCLUSIONS

Bleomycin was more effective than TAC, 5-FU, or TAC combined with 5-FU for treating keloids and hypertrophic scars with lower skin atrophy and telangiectasia risks. However, it may cause more pain than 5-FU or TAC. Further comprehensive studies, including RCTs, are required for objective analysis.

An Update on Molecular Mechanisms of Scarring-A Narrative Review

Fibroblasts, the principal cellular mediators of connective tissue remodeling, play a crucial role in the formation of physiological and pathological scars. Understanding the intricate interplay between fibroblasts and other cellular and molecular components is essential for elucidating the underlying mechanisms driving scar formation. Hypertrophic scars, keloids and atrophic scars arise from dysregulated wound healing processes characterized by persistent inflammation, aberrant collagen deposition, and impaired extracellular matrix remodeling. Fibroblasts play a central role in the pathogenesis of such pathological scars, driving aberrant extracellular matrix remodeling, subsequently contributing to the formation of raised or depressed fibrotic lesions. The investigation of complex interactions between fibroblasts and the microenvironment is crucial for developing targeted therapeutic interventions aimed at modulating fibroblast activity and improving clinical outcomes in patients with pathological scars. Further research into the molecular pathways governing fibroblast behavior and their heterogeneity holds promise for advancing scar management strategies. This narrative review was performed to shed light on the mechanisms behind scar formation, with a special focus on the role of fibroblasts in the formation of different types of scars, providing insights into the pathophysiology of these conditions. Through the analysis of current knowledge, this review seeks to identify the key cellular and molecular mechanisms involved in fibroblast activation, collagen synthesis, and extracellular matrix remodeling in hypertrophic scar, keloid, or atrophic scar formation.

Multifunctional Nanofiber Membranes Constructed by Microfluidic Blow-Spinning to Inhibit Scar Formation at Early Intervention Stage

Pathological scarring has been a challenge in skin injury repair since ancient times, and prophylactic treatment in the early stages of wound healing usually results in delayed wound healing. In this study, poly(ethylene oxide) (PEO) and chitosan (CTS) were used as carrier materials to construct multifunctional pirfenidone (PFD)/CTS/PEO (PCP) nanofiber membranes (NFMs) loaded with PFD by microfluidic blow-spinning (MBS). MBS is a good method for quickly, safely, and greenly constructing large-area manufacturing of inexpensive NFMs. PCP NFMs were uniform in external morphology, with diameters ranging from 200 to 500 nm. The encapsulation efficiency of the drug-loaded PCP NFMs was above 80%, which had a good slow release, visualization, water absorption, and biocompatibility. The inhibitory effect of PCP NFMs on normal human dermal fibroblasts was dose-dependent and inhibited the expression of the transforming growth factor-β1/SMAD family member 3 (TGF-β1/SMAD3) signaling pathway. PCP NFMs showed significant antibacterial effects against both Staphylococcus aureus and Escherichia coli. In the rabbit ear scar experiment, the wound healed about 70% on day 5 and almost completely on day 10 after PCP-3 NFMs treatment, with the thinnest scar tissue, skin color, tenderness close to normal tissue, and a Vancouver scar scale score of less than 5. PCP-3 NFMs had good effects on anti-inflammatory, wound healing, and collagen-I deposition reducing effects. In conclusion, PCP-3 NFMs can both promote wound healing and intervene to inhibit pathological scarring in advance, making them a potential multifunctional wound dressing for early prevention and treatment of pathological scarring.

Repair and regeneration: ferroptosis in the process of remodeling and fibrosis in impaired organs

As common clinical-pathological processes, wound healing and tissue remodelling following injury or stimulation are essential topics in medical research. Promoting the effective healing of prolonged wounds, improving tissue repair and regeneration, and preventing fibrosis are important and challenging issues in clinical practice. Ferroptosis, which is characterized by iron overload and lipid peroxidation, is a nontraditional form of regulated cell death. Emerging evidence indicates that dysregulated metabolic pathways and impaired iron homeostasis play important roles in various healing and regeneration processes via ferroptosis. Thus, we review the intrinsic mechanisms of tissue repair and remodeling via ferroptosis in different organs and systems under various conditions, including the inflammatory response in skin wounds, remodeling of joints and cartilage, and fibrosis in multiple organs. Additionally, we summarize the common underlying mechanisms, key molecules, and targeted drugs for ferroptosis in repair and regeneration. Finally, we discuss the potential of therapeutic agents, small molecules, and novel materials emerging for targeting ferroptosis to promote wound healing and tissue repair and attenuate fibrosis.

The Role of Extracorporeal Shock Wave Therapy in Keloids and Hypertrophic Scars: A Systematic Review

Keloids and hypertrophic scars are pathological scars that result from a prolonged and aberrant response to wound healing, resulting in raised and thickened skin lesions. Traditional treatments include occlusive dressings, compression therapy, intralesional steroids, and surgical excision with refashioning. Extracorporeal shock wave therapy (ESWT) is a non-invasive treatment method that employs mechanotransduction to stimulate a biological cascade resulting in tissue regeneration. This review aims to explore the literature for published evidence on the role of ESWT in the treatment of keloids and hypertrophic scars. A literature search following the PRISMA guidelines was conducted on PUBMED, Google Scholar, and the Cochrane Database of Systematic Reviews, for studies demonstrating the use of ESWT in keloids and hypertrophic scars. From this, 79 articles were identified, 12 of which met the eligibility criteria and were thus analyzed and included in the study. As monotherapy for keloids, ESWT showed comparable improvements in functional and aesthetic outcomes compared to traditional intralesional steroid therapy. Keloids treated with combination therapy of ESWT with intralesional steroids had better outcomes than those treated with intralesional steroids alone. Improvements in hypertrophic scar cosmesis, discomfort, and function with the use of ESWT were reported. Histologic improvements such as decreased collagen content, reduction of fibrotic markers, and fibrogenic cytokines were also described. ESWT is a promising treatment modality for pathological scars, offering comparable outcomes to traditional therapies with added benefits such as non-invasiveness. Further research is warranted to establish optimal protocols and its role in pathological scar management.

Scar matrix drives Piezo1 mediated stromal inflammation leading to placenta accreta spectrum

Scar tissue formation is a hallmark of wound repair in adults and can chronically affect tissue architecture and function. To understand the general phenomena, we sought to explore scar-driven imbalance in tissue homeostasis caused by a common, and standardized surgical procedure, the uterine scar due to cesarean surgery. Deep uterine scar is associated with a rapidly increasing condition in pregnant women, placenta accreta spectrum (PAS), characterized by aggressive trophoblast invasion into the uterus, frequently necessitating hysterectomy at parturition. We created a model of uterine scar, recapitulating PAS-like invasive phenotype, showing that scar matrix activates mechanosensitive ion channel, Piezo1, through glycolysis-fueled cellular contraction. Piezo1 activation increases intracellular calcium activity and Protein kinase C activation, leading to NF-κB nuclear translocation, and MafG stabilization. This inflammatory transformation of decidua leads to production of IL-8 and G-CSF, chemotactically recruiting invading trophoblasts towards scar, initiating PAS. Our study demonstrates aberrant mechanics of scar disturbs stroma-epithelia homeostasis in placentation, with implications in cancer dissemination.

Increased Susceptibility to Mechanical Stretch Drives the Persistence of Keloid Fibroblasts: An Investigation Using a Stretchable PDMS Platform

BACKGROUND

Keloids are a common fibrotic disease of the skin, with the pathological hallmark of excessive extracellular matrix synthesis due to abnormal fibroblast activity. Since keloids clinically arise in areas of high mechanical tension, the mechanotransductory pathway may be attributed to its pathogenesis. We aimed to establish a preclinical platform to elucidate the underlying mechanism of keloid development and its clinical persistence.

METHODS

We fabricated a mechanically stretchable polydimethylsiloxane cell culture platform; with its mimicry of the in vivo cyclic stretch of skeletal muscles, cells showed higher proliferation compared with conventional modalities.

RESULTS

In response to mechanical strain, TGF-β and type 1 collagen showed significant increases, suggesting possible TGF-β/Smad pathway activation via mechanical stimulation. Protein candidates selected by proteomic analysis were evaluated, indicating that key molecules involved in cell signaling and oxidative stress were significantly altered. Additionally, the cytoskeletal network of keloid fibroblasts showed increased expression of its components after periodic mechanical stimulation.

CONCLUSIONS

Herein, we demonstrated and validated the existing body of knowledge regarding profibrotic mechanotransduction signaling pathways in keloid fibroblasts. Cyclic stretch, as a driving force, could help to decipher the tension-mediated biomechanical processes, leading to the development of optimized therapeutic targets.

Using network pharmacology to discover potential drugs for hypertrophic scars

BACKGROUND

Hypertrophic scarring is a disease of abnormal skin fibrosis caused by excessive fibroblast proliferation. Existing drugs have not achieved satisfactory therapeutic effects.

OBJECTIVES

To explore the molecular pathogenesis of hypertrophic scars and screen effective drugs for their treatment.

METHODS

Existing human hypertrophic scar RNA sequencing data were utilized to search for hypertrophic scar-related gene modules and key genes through weighted gene co-expression network analysis (WGCNA). Candidate compounds were screened in a compound library. Potential drugs were screened by molecular docking and verified in human hypertrophic scar fibroblasts and a mouse mechanical force hypertrophic scar model.

RESULTS

WGCNA showed that hypertrophic scar-associated gene modules influence focal adhesion, the transforming growth factor (TGF)-β signalling pathway and other biologic pathways. Integrin β1 (ITGB1) is the hub protein. Among the candidate compounds obtained by computer virtual screening and molecular docking, crizotinib, sorafenib and SU11274 can inhibit the proliferation and migration of human hypertrophic scar fibroblasts and profibrotic gene expression. Crizotinib had the best effect on hypertrophic scar attenuation in mouse models. At the same time, mouse ITGB1 small interfering RNA can also inhibit mouse scar hyperplasia.

CONCLUSIONS

ITGB1 and TGF-β signalling pathways are important for hypertrophic scar formation. Crizotinib could be a potential treatment drug for hypertrophic scars.

Clinical Effect of Dermatologic Trephination Combined With Radiotherapy in the Treatment of Keloids

BACKGROUND

Keloids are excessive formations of scar tissue that develop at the site of a skin injury. Due to their invasive nature, they have a negative impact on the skin's appearance and are prone to recurrence, making them a challenging condition to treat with regard to skin aesthetics.

OBJECTIVES

The objective of this article was to compare the long-term effects of dermatologic trephination with nonsurgical treatments for scars and evaluate the clinical value of the treatments.

METHODS

A retrospective analysis was conducted of 48 patients who received keloid treatment in the Department of Dermatology and Department of Thoracic Surgery at our hospital from January 2021 to October 2023. Twenty-four patients received dermatologic trephination, and 24 patients received nonsurgical treatment. Outcome measures included scar appearance, scar healing time, pain and itching levels, and patient satisfaction.

RESULTS

The healing time of patients receiving dermatologic trephination was significantly shorter than that of patients in the nonsurgical group. The degree of itching in patients undergoing dermatologic trephination was significantly lower than that of patients in the nonsurgical group. The satisfaction of patients who received dermatologic trephination was significantly higher than that of patients in the nonsurgical group.

CONCLUSIONS

In this study we demonstrated that trephination achieves better long-term results in keloid revision, including improved keloid appearance, itching symptoms, and patient satisfaction.

LEVEL OF EVIDENCE: 3

A study of scarless wound healing through programmed inflammation, proliferation and maturation using a redox balancing nanogel

In the study, we have shown the efficacy of an indigenously developed redox balancing chitosan gel with impregnated citrate capped Mn3O4 nanoparticles (nanogel). Application of the nanogel on a wound of preclinical mice model shows role of various signaling molecules and growth factors, and involvement of reactive oxygen species (ROS) at every stage, namely hemostasis, inflammation, and proliferation leading to complete maturation for the scarless wound healing. While in vitro characterization of nanogel using SEM, EDAX, and optical spectroscopy reveals pH regulated redox buffering capacity, in vivo preclinical studies on Swiss albino involving IL-12, IFN-γ, and α-SMA signaling molecules and detailed histopathological investigation and angiogenesis on every stage elucidate role of redox buffering for the complete wound healing process.

Improvement in Early Scar Maturation by Nanofat Infiltration: Histological and Spectrophotometric Preliminary Results From a Split Scar-Controlled, Randomized, Double-Blinded Clinical Trial

Background

The regenerative properties of stromal vascular fraction (SVF) in wound healing and scar formation are a subject of increasing clinical interest.

Objectives

Although preclinical studies have confirmed the angiogenetic, proliferative, and antifibrotic properties of SVF, there is limited clinical evidence from randomized controlled clinical trials.

Methods

Twelve patients who underwent abdominoplasty were included in this clinical study. Nanofat was mechanically obtained intraoperatively and infiltrated intradermally in the sutured surgical wound, randomly assigned to either the left or the right side. The abdominal scar was evaluated with the Patient and Observer Scar Assessment Scale, whereas erythema and pigmentation were measured with a reflectance spectrophotometry device (Mexameter, Courage + Khazaka electronic GmbH, Köln,Germany). Histological analysis and electron scan microscopy of tissue biopsies were performed at 8 months.

Results

The treated side of the scar showed significantly less erythema at 3- and 6-month follow-ups, but this difference reduced after 12 months. Patients reported better scar scores at the 6-month follow-up with a significantly better color at the treated side. Observers reported better overall scar scores at the treated side at 3-, 6-, and 12-month follow-ups, with better vascularization, pigmentation, and thickness. There was no statistically significant difference in terms of histological analysis between the 2 groups. There was no difference in the occurrence of adverse events between both sides.

Conclusions

Infiltration of nanofat exhibited promising results in surgical scar maturation characterized by less erythema and better texture. More clinical trials with a larger sample size are warranted to better elucidate the possible benefits of SVF on surgical scar formation.

Level of Evidence 5

Comprehensive Insights into Keloid Pathogenesis and Advanced Therapeutic Strategies

Keloid scars, characterized by abnormal fibroproliferation and excessive extracellular matrix (ECM) production that extends beyond the original wound, often cause pruritus, pain, and hyperpigmentation, significantly impacting the quality of life. Keloid pathogenesis is multifactorial, involving genetic predisposition, immune response dysregulation, and aberrant wound-healing processes. Central molecular pathways such as TGF-β/Smad and JAK/STAT are important in keloid formation by sustaining fibroblast activation and ECM deposition. Conventional treatments, including surgical excision, radiation, laser therapies, and intralesional injections, yield variable success but are limited by high recurrence rates and potential adverse effects. Emerging therapies targeting specific immune pathways, small molecule inhibitors, RNA interference, and mesenchymal stem cells show promise in disrupting the underlying mechanisms of keloid pathogenesis, potentially offering more effective and lasting treatment outcomes. Despite advancements, further research is essential to fully elucidate the precise mechanisms of keloid formation and to develop targeted therapies. Ongoing clinical trials and research efforts are vital for translating these scientific insights into practical treatments that can markedly enhance the quality of life for individuals affected by keloid scars.

Magneto-responsive biocomposites in wound healing: from characteristics to functions

The number of patients with non-healing wounds continuously increases, and has become a prominent societal issue that imposes a heavy burden on both patients and the entire healthcare system. Although traditional dressings play an important role in wound healing, the complexity and diversity of the healing process pose serious challenges in this field. Magneto-responsive biocomposites, with their excellent biocompatibility, remote spatiotemporal controllability, and unique convenience, demonstrate enticing advantages in the field of wound dressings. However, current research on magneto-responsive biocomposites as wound dressings lacks comprehensive and in-depth reviews, which to some extent, restricts the deeper understanding and further development of this field. Based on this, this paper reviews the latest advances in magnetic responsive wound dressings for wound healing. First, we review the process of skin wound healing and parameters for assessing repair progress. Then, we systematically discuss the preparation strategies and unique characteristics of magneto-responsive biocomposites, focusing on magneto-induced orientation, magneto-induced mechanical stimulation, and magnetocaloric effect. Subsequently, this review elaborates the multiple mechanisms of magneto-responsive biocomposites in promoting wound healing, including regulating cell behavior, enhancing electrical signal, controlling drug release, and accelerating tissue reconstruction. Finally, we further propose the development direction and future challenges of magnetic responsive biomaterials as wound dressings in clinical application.

Recurrence and Complications of Peri-operative Steroid Injection of Keloids: A Systematic Review and Meta-analysis

Keloid scars are a particularly challenging fibroproliferative wound healing disorder with a variety of proposed management approaches including concurrent surgery and intralesional steroid injection. We aimed to identify the optimum time for triamcinolone injection of keloids, by comparing the recurrence and complication occurrence in patients who received pre-, intra- or post-operative injection. Studies reporting on the rate of recurrence and complication occurrence following treatment of keloid scarring with concurrent surgical excision and intralesional steroid injection were identified from the PubMed, Web of science and Embase databases. The I-squared (I2) statistic was used to quantify the variability in study estimates due to heterogeneity and to determine whether the fixed or random effect models will be employed. Publication bias was visualized through funnel plots and tested with the Egger's test. We found that the recurrence rate was significantly lower with post-operative injection compared to intra-operative injection (p < 0.001) and pre-operative injection (p = 0.009). A significant difference between intra-operative and pre-operative injection was not found (p = 0.46). In conclusion, post-operative steroid injection after surgical excision results in lower keloid recurrence compared to pre- and intra-operative injection.Level of Evidence IV "This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 ."

Post-surgical Hypertrophic Scar in a Patient With Unilateral Temporomandibular Joint Ankylosis

Wound healing is nature's response to injury. It is a complex and dynamic process involving multiple biological systems aimed at restoring the integrity of damaged tissue. The temporomandibular joint (TMJ) is a critical anatomical structure that facilitates jaw movement and function. TMJ ankylosis is a pathological condition characterized by fusion of the mandibular condyle to the glenoid fossa resulting in severe restriction in mouth opening and significantly reduced mandibular movements. This condition affects the patient's quality of life by deteriorating major functions such as mastication, speech, oral hygiene, breathing, facial growth, and esthetics. Gap arthroplasty is the mainstay of treatment. There are various surgical approaches to TMJ such as Al-Kayat Bramley, Popowich's modification, Blair's inverted hockey stick, Dingman's, Thoma's, endaural, postauricular, and rhytidectomy incisions. Wound healing in the TMJ region poses unique challenges due to its complex anatomy and the high level of mechanical stress it endures. Following trauma to TMJ, hematomas are organized by fibrous granulation tissues and mesenchymal stem cells are recruited from adjacent bone by cytokines and chemokines such as bone morphogenetic proteins, transforming growth factor-beta and stromal cell-derived factor 1. These recruited mesenchymal cells differentiate into osteoprogenitors and osteoblasts to form new bone and fibroblasts to form a scar. In humans, scarring is the final outcome of the wound healing process, which has evolved to rapidly repair injuries. Scarring from injuries, surgeries, and burns places a significant burden on the healthcare system. Patients with major scars, especially children and adolescents, often experience long-term functional and psychological issues. This article aims to present a case of post-surgical hypertrophic scar in a patient after gap arthroplasty through Al-Kayat Bramley incision and the role of a multi-professional team to treat such wounds.