In the face and neck, keloid scar distribution is related to skin thickness and stiffness changes associated with movement.

Keloid scars tend to occur in high-tension sites due to mechanical stimuli that are involved in their development. To date, a detailed analysis of keloid distribution focused specifically on facial and neck areas has not been reported, and limited literature exists as to the related mechanical factors. To rectify this deficiency of knowledge, we first quantified the facial and neck keloid distribution observed clinically in 113 patients. Subsequently, we performed a rigorous investigation into the mechanical factors and their associated changes at these anatomic sites in healthy volunteers without a history of pathologic scarring. The association between keloid-predilection sites and sebaceous gland-dense and acne-prone sites was also examined. To assess skin stretch, thickness and stiffness, VECTRA, ultrasound and indentometer were utilised. Baseline skin stiffness and thickness were measured, as well as the magnitude of change in these values associated with facial expression and postural changes. Within the face and neck, keloids were most common near the mandibular angle (41.3%) and lateral submental (20.0%) regions. These areas of increased keloid incidence were not associated with areas more dense in sebaceous glands, nor linked consistently with acne-susceptible regions. Binomial logistic regression revealed that changes in skin stiffness and thickness related to postural changes significantly predicted keloid distribution. Skin stiffness and thickness changes related to prolonged mechanical forces (postural changes) are most pronounced at sites of high keloid predilection. This finding further elucidates the means by which skin stretch and tension are related to keloid development. As a more detailed analysis of mechanical forces on facial and neck skin, this study evaluates the nuances of multiple skin-mechanical properties, and their changes in a three-dimensional framework. Such factors may be critical to better understanding keloid progression and development in the face and neck.

The effects of systemic diseases, genetic disorders and lifestyle on keloids.

Keloid are a fibroproliferative disorder caused by abnormal healing of skin, specifically reticular dermis, when subjected to pathological or inflammatory scars demonstrating redness, elevation above the skin surface, extension beyond the original wound margins and resulting in an unappealing cosmetic appearance. The severity of keloids and risk of developing keloids scars are subjected to elevation by other contributing factors such as systemic diseases, general health conditions, genetic disorders, lifestyle and natural environment. In particular, recently, daily physical work interpreted into mechanical force as well as the interplay between mechanical factors such as stress, strain and stiffness have been reported to strongly modulate the cellular behaviour of keloid formation, affect their location and shape in keloids. Herein, we review the extensive literature on the effects of these factors on keloids and the contributing predisposing mechanisms. Early understanding of these participating factors and their effects in developing keloids may raise the patient awareness in preventing keloids incidence and controlling its severity. Moreover, further studies into their association with keloids as well as considering strategies to control such factors may help clinicians to prevent keloids and widen the therapeutic options.

Ear Keloid as an Unusual Complication of Prolonged Mask Use during the COVID-19 Pandemic.

The recent COVID-19 pandemic required many people to wear ear-loop face masks (ELFMs) for protracted periods, and ear injuries have been reported. Here, we report a rare case of a keloid on the right posterior ear that appeared to arise from prolonged ELFM use. A 76-year-old Japanese man presented with a 7.3 × 2.2 × 1.4-cm keloid running from the medial retroauricular sulcus to the posterior lobule. The lack of keloid history suggested the absence of genetic risk factors. The patient reported extensive mask-wearing habits that were augmented by the pandemic. The keloid developed from an ear injury. Although it healed well, it started thickening 2 months later. Because local mechanical forces (eg, pressure/friction) can promote keloid growth, the ELFM may have provoked the keloid. The patient disclosed a history of uncontrolled hypertension and diabetes mellitus, which associate with severe keloids. The whole keloid was removed via total excision, and the defect was closed primarily and subjected to 15Gy/2Fr radiotherapy. The patient was advised to use a different mask type. Twelve months later, the scar had healed without complications or recurrence and with good cosmetic outcomes. Thus, ELFMs can promote retroauricular keloid formation, possibly by imposing local pressure/friction. ELFMs may also raise local skin temperatures and humidity, thereby fostering infection, which can trigger keloids. Hypertension/diabetes may further elevate the risk of EFLM-induced keloid. Thus, an auricular keloid is an unusual complication of prolonged ELFM use. Combination therapy can have excellent outcomes. Patients with keloid risk factors should be advised to use face masks without ear loops.

Adherent Abdominal Scar Revision Does Not Require Total Scar Removal.

Abdominal surgery can cause notable scars that adhere to the abdominal tissues below. Full scar removal is generally not recommended due to the risk of intestinal damage and delayed wound healing. Here, we describe a surgical scar-revision procedure for adherent abdominal scars that does not involve either opening the abdominal cavity or total scar removal. A 58-year-old woman exhibited an aesthetically displeasing hypertrophic adherent abdominal scar that extended from the umbilical fold to the pubic area and distorted the umbilicus. It arose from multiple laparotomies for hernia repair and subsequent complications. Pain/discomfort and functional impairment were absent. Scar-revision surgery was conducted under general anesthesia. The skin around the adherent scar was excised down to the subcutaneous layer with a minimal margin. However, only the epidermis and superficial dermal layer of the adherent scar were removed; the deep scar dermis remained. The skin flaps on either side of the midline were then advanced and sutured over the remnant dermis. One year after surgery, the aesthetic and functional outcomes were excellent. Furthermore, no hypertrophic scars or epidermal cysts were found. This technique is effective, efficient, does not involve intraabdominal procedures, provides a vascularized tissue layer, and results in an aesthetically pleasing scar.

Allometrically scaling tissue forces drive pathological foreign-body responses to implants via Rac2-activated myeloid cells.

Small animals do not replicate the severity of the human foreign-body response (FBR) to implants. Here we show that the FBR can be driven by forces generated at the implant surface that, owing to allometric scaling, increase exponentially with body size. We found that the human FBR is mediated by immune-cell-specific RAC2 mechanotransduction signalling, independently of the chemistry and mechanical properties of the implant, and that a pathological FBR that is human-like at the molecular, cellular and tissue levels can be induced in mice via the application of human-tissue-scale forces through a vibrating silicone implant. FBRs to such elevated extrinsic forces in the mice were also mediated by the activation of Rac2 signalling in a subpopulation of mechanoresponsive myeloid cells, which could be substantially reduced via the pharmacological or genetic inhibition of Rac2. Our findings provide an explanation for the stark differences in FBRs observed in small animals and humans, and have implications for the design and safety of implantable devices.

Congress Report on the Second World Congress of Global Scar Society with Scar Academy and Japan Scar Workshop.

Pathological scars (including keloids, hypertrophic scars, and scar contractures) are present with high severity among certain populations, particularly in Asians and Africans who are highly prone to develop scars. Understanding the patho-mechanism that underlies scarring, such as mechanosignaling, systemic, and genetic factors, as well as optimal surgical techniques and integrated noninvasive therapeutic methods can guide clinicians to develop treatment protocols that can overcome these issues. This report summarizes a congress at Pacifico Yokohama (Conference Center) on December 19, 2021 involving researchers and clinicians from diverse disciplines who convened to discuss current clinical, preclinical, and most recent research advances in understanding pathological scarring, keloid and hypertrophic scar management, and research progress in wound healing. Presenters described the advances in scar therapies, understanding scarring mechanisms, and scar prevention and assessments tools. Moreover, presenters addressed the challenges during the COVID-19 pandemic and using telemedicine in management of scar patients.

Keloidal Collagen May Be Produced Directly by αSMA-positive Cells: Morphological Analysis and Protein Shotgun Analysis.

Keloids are fibroproliferative lesions caused by abnormal dermal wound healing. Keloidal collagen (KC) is a pathognomic feature of keloids, but the mechanism by which it forms is unknown. This study aimed to evaluate the histopathology of KC and thereby gain clues into how it forms. Methods: The cross-sectional study cohort consisted of a convenience series of patients with keloids who underwent surgical excision. Skin pieces (3 mm2) were collected from the keloid center and nearby control skin. Histopathology was conducted with light and electron microscopy and immunohistochemistry. KC composition was analyzed with protein shotgun analysis. Results: Microscopic analyses revealed the ubiquitous close association between KC and αSMA-positive spindle-shaped cells that closely resembled myofibroblasts. Neither KC nor the spindle-shaped cells were observed in the control tissues. Compared with control skin, the collagen fibers in the KC were overall thinner, their diameter varied more, and their spacing was irregular. These features were particularly pronounced in the collagens in the vicinity of the spindle-shaped cells. Protein shotgun analysis did not reveal a specific collagen in KC but showed abnormally high abundance of collagens I, III, VI, XII, and XIV. Conclusions: These findings suggest that KC may be produced directly by myofibroblasts rather than simply being denatured collagen fibers. Because collagens VI and XII associate with myofibroblast differentiation, and collagen XIV associates with local mechanical stress, these collagens may reflect, and perhaps contribute to, the keloid-specific local conditions that lead to the formation of KC.

Vesicocutaneous fistula due to vesical diverticulitis with stones: A case report and literature review.

Introduction: We encountered an extremely rare case of a vesicocutaneous fistula due to vesical diverticulitis with stones. Case presentation: A 78-year-old male patient presented to our department with complaints of suppurative discharge in the suprapubic area. Computed tomography revealed an enlarged prostate, a vesical diverticulum with stones located on the ventral side, and an aberrant connection between the anterior bladder wall and the external surface of the skin. The patient was diagnosed with a vesicocutaneous fistula due to vesical diverticulitis and was successfully treated with a multidisciplinary approach including vesical diverticulectomy with stone removal and nonviable tissue debridement. The patient continues to receive regular outpatient follow-ups with urinary catheter changes. Conclusion: Vesicocutaneous fistulas due to vesical diverticulitis with stones are extremely rare. We should be aware that a vesical diverticulum with stones located on the ventral side might pose a high-risk factor for the formation of a vesicocutaneous fistula in elderly patients.

Fibroma of the tendon sheath in the dorsum of the foot: A case report.

Fibroma of tendon sheath (FTS) is a rare soft tissue tumor that usually occurs in the upper extremity. Moreover, of the few cases reported in the feet, nearly all occur in the plantar region. We report the case of a large FTS in the dorsum of the left foot that grew quickly into a 4 cm-diameter lesion. The 44-year-old Japanese man noticed the tumor incidentally one year before presentation and could not recall any possible cause. Physical examination showed an elastic hard mass that spread over the third to fifth metatarsal bones. MRI showed iso-intense signals with central hypo-intensity on T1-weighted images and hypo-intense signals on T2-weighted images. Since a biopsy did not reveal any malignant findings, the lesion was excised surgically. The tumor was found to be multilocular, encapsulated, and to arise from the extensor digitorum brevis tendon. Histopathology showed scattered spindle fibroblasts and slit-like vascular structures within the dense collagenous matrix. The tumor was diagnosed on the basis of the clinical, demographic, surgical, and histopathological findings as an FTS arising from the extensor digitorum brevis tendon. A review of the literature revealed seven cases of FTS of the dorsum of the foot, which indicates its rarity. More than one-half of these cases were from Japan. While the cause of FTS remains unclear, trauma has been implicated. We suggest that the cultural background of the patient, which could promote kneeling-induced dorsal foot trauma, may have contributed to the onset/progression of our case. Level of Clinical Evidence: 4.

Combination Therapy for a Severe Axillary Keloid with Abscesses: A Case Report.

Keloids are laterally growing fibroproliferative skin disorders. Severe keloids spread widely, sometimes over joints, thus significantly limiting motor function. They are associated with recurrent, very painful draining infections. Here, we report a case of a giant keloid that was successfully treated by combination therapy comprising surgery (partial resection followed by local flap transposition) and subsequent radiotherapy and steroid-plaster therapy. The keloid was first noticed when the patient was 7 years old at the site of a Bacille Calmette-Guérin vaccination she had received on her left shoulder in infancy. The keloid grew rapidly and widely after adulthood. A malignant tumor was suspected at another hospital, but a biopsy at age 45 years indicated the lesion was a keloid. Later, the keloid grew from the shoulder onto the chest and back and over the anterior axilla. At age 62 years, the patient was referred to our hospital. Under general anesthesia, the keloid was partially resected and the wound was covered with a local flap. Postoperative radiotherapy was performed 1 week later. The residual keloid was treated for 18 months with steroid tape. At 18 months after surgery, no recurrence of the keloid was observed. The patient had no pain or movement restriction. She was extremely satisfied with the results and considered the treatment to have improved her quality of life. While a standard strategy for severe keloid remains to be established, combination therapy comprising surgery, postoperative radiotherapy, and steroid-plaster therapy that aims to reduce inflammation and skin tension may be an option.

Keloidal dermatofibroma: Clinicopathological comparison of 52 cases with a series of 2077 other dermatofibromas.

Dermatofibroma is a common benign skin lesion with a contested etiology: some believe it is a neoplasm while others propose minor injuries initiate it. Many dermatofibroma variants have been described, including keloidal dermatofibroma, which is unusual by bearing keloidal collagen. Keloidal dermatofibroma was first described in 1998 and only 15 cases have been reported. Since keloids are driven by skin injuries, the existence of keloidal dermatofibroma has been suggested to support the injury hypothesis of dermatofibroma etiology. To better understand keloidal dermatofibroma characteristics and gain clues regarding dermatofibroma etiology, consecutive keloidal dermatofibroma cases (n = 52) and dermatofibroma without keloidal collagen (n = 2077) that were histopathologically diagnosed in 2016-2019 were identified from the records of a Japanese dermatopathology laboratory and compared in terms of demographic, clinical, and histopathological characteristics by univariate analyses. Compared to other dermatofibromas, keloidal dermatofibromas occurred more frequently on the forearm and hand (P < 0.0001 and 0.0019), especially the wrist dorsum, and in the superficial skin layer (P < 0.0001). Keloidal dermatofibromas also demonstrated more cellularity and hemorrhage (both P < 0.0001). Correlation analyses between keloidal collagen amount and keloidal dermatofibroma size (a proxy of time-since-onset) did not support the notion that keloidal collagen deposition and keloidal dermatofibroma formation are triggered simultaneously. Recent injury, as indicated by fresh hemorrhage, was equally common in putatively older and younger keloidal dermatofibromas. Thus, keloidal collagen in keloidal dermatofibromas could be due to injury to preexisting dermatofibromas, which suggests that the keloidal dermatofibroma entity does not prove the injury hypothesis. Commonalities between keloids and keloidal dermatofibromas suggest a link between genetics, provocative events that induce myofibroblast differentiation, and keloidal collagen production.

In Vivo Analysis of the Superficial and Deep Fascia.

BACKGROUND: Key risk factors for hypertrophic scarring and surgical-site infections are high-tension wounds, fat necrosis, and dead space. All could be prevented by appropriate superficial fascia suturing. However, the as-yet poorly researched anatomy of the superficial fascia should be delineated. This study is the first to quantify the superficial fascia throughout the human body in vivo. METHODS: Ultrasound was used to analyze the superficial and deep fascia of 10 volunteers at 73 points on 11 body regions, including the upper and lower trunk and limbs. Number, thickness and percentage of superficial fascia layers, and deep fascia and dermis thickness, were measured at each point. RESULTS: Seven hundred thirty ultrasound images were analyzed. Body regions varied markedly in terms of subcutaneous variables. Posterior chest had the thickest deep fascia and dermis and the highest average superficial fascia layer thickness [0.6 mm (95 percent CI, 0.6 to 0.7 mm)]. Anterior chest had the most superficial fascia layers [3.7 (95 percent CI, 3.5 to 3.8)]. Posterior and anterior chest had among the highest percentage of superficial fascia. Abdomen and especially gluteus had a low percentage of superficial fascia. Covariate analyses confirmed that posterior and anterior chest generally had higher superficial fascia content than gluteus and abdomen (both p < 0.001). They also showed that the dermis in the posterior and anterior chest increased proportionally to total fascia thickness. CONCLUSIONS: The superficial fascia, deep fascia, and dermis tend to be thick in high-tension areas such as the upper trunk. A site-specific surgical approach is recommended for subcutaneous sutures. CLINICAL RELEVANCE STATEMENT: Understanding the anatomical distribution of the superficial fascia and deep fascia will help surgeons optimize subcutaneous fasciae suturing, thereby potentially reducing the incidence of surgical-site infections and hypertrophic scars.

Hemodynamics and Vascular Histology of Keloid Tissues and Anatomy of Nearby Blood Vessels.

Keloids are red' invasive scars that are driven by chronic inflammation in the reticular dermis. The role of blood vessels in keloid behavior remains poorly understood. In the present study with 32 keloid patients, we examined the hemodynamics of keloid tissue, the anatomy of the blood vessels feeding and draining the keloids, and the vascular histology of keloids. Methods: Ten patients with large anterior chest keloids underwent near-infrared spectroscopy, which measured regional saturation of oxygen and total hemoglobin index in the keloid and surrounding skin. Another 10 patients with large chest keloids and three healthy volunteers underwent multidetector-low computed tomography. The extirpated chest keloids of 12 patients were subjected to histology with optical, CD31 immunohistochemical, and electron microscopy. Results: All keloids had a low regional saturation of oxygen and a high total hemoglobin index, which is indicative of blood congestion. Multidetector-low computed tomography revealed dilation of the arteries and veins that were respectively feeding and draining the keloid leading edge. Hematoxylin-eosin staining and CD31 immunohistochemisty revealed considerable neovascularization in the keloid leading edge but not in the center. Electron microscopy showed that the lumens of many vessels in the keloid center appeared to be occluded or narrowed. Conclusions: Keloids seem to be congested because of increased neovascularization and arterial inflow at the leading edge and blocked outflow due to vascular destruction in the center. The surrounding veins seem to expand in response to this congested state. Methods that improve the blood circulation in keloids may be effective therapies.

Disrupting biological sensors of force promotes tissue regeneration in large organisms.

Tissue repair and healing remain among the most complicated processes that occur during postnatal life. Humans and other large organisms heal by forming fibrotic scar tissue with diminished function, while smaller organisms respond with scarless tissue regeneration and functional restoration. Well-established scaling principles reveal that organism size exponentially correlates with peak tissue forces during movement, and evolutionary responses have compensated by strengthening organ-level mechanical properties. How these adaptations may affect tissue injury has not been previously examined in large animals and humans. Here, we show that blocking mechanotransduction signaling through the focal adhesion kinase pathway in large animals significantly accelerates wound healing and enhances regeneration of skin with secondary structures such as hair follicles. In human cells, we demonstrate that mechanical forces shift fibroblasts toward pro-fibrotic phenotypes driven by ERK-YAP activation, leading to myofibroblast differentiation and excessive collagen production. Disruption of mechanical signaling specifically abrogates these responses and instead promotes regenerative fibroblast clusters characterized by AKT-EGR1.

A New Model for Specific Visualization of Skin Graft Neoangiogenesis Using Flt1-tdsRed BAC Transgenic Mice.

BACKGROUND: Neovascularization plays a critical role in skin graft survival. Up to date, the lack of specificity to solely track the newly sprouting blood vessels has remained a limiting factor in skin graft transplantation models. Therefore, the authors developed a new model by using Flt1-tdsRed BAC transgenic mice. Flt1 is a vascular endothelial growth factor receptor expressed by sprouting endothelial cells mediating neoangiogenesis. The authors determined whether this model reliably visualizes neovascularization by quantifying tdsRed fluorescence in the graft over 14 days. METHODS: Cross-transplantation of two full-thickness 1 × 1-cm dorsal skin grafts was performed between 6- to 8-week-old male Flt1 mice and KSN/Slc nude mice (n = 5). The percentage of graft area occupied by tdsRed fluorescence in the central and lateral areas of the graft on days 3, 5, 9, and 14 was determined using confocal-laser scanning microscopy. RESULTS: Flt1+ endothelial cells migrating from the transgenic wound bed into the nude graft were first visible in the reticular dermis of the graft center on day 3 (0.5 ± 0.1; p < 0.05). Peak neovascularization was observed on day 9 in the lateral and central parts, increasing by 2- to 4-fold (4.6 ± 0.8 and 4.2 ± 0.9; p < 0.001). Notably, some limited neoangiogenesis was displayed within the Flt grafts on nude mice, particularly in the center. No neovascularization was observed from the wound margins. CONCLUSION: The ability of the Flt1-tdsRed transgenic mouse model to efficiently identify the origin of the skin-graft vasculature and visualize graft neovascularization over time suggests its potential utility for developing techniques that promote graft neovascularization.

Anterior Neck-scar Contracture Reconstruction Using a Long Skin-pedicled Flap.

We previously reported cases of anterior-neck reconstruction using super-thin and perforator-supercharged skin-pedicled flaps harvested from the pectoral area and back. Here, we reconstructed a neck-scar contracture with a long skin-pedicled flap from the pectoral area that survived without congestion despite not being supercharged with a perforator, as planned. The patient, a 67-year-old man, was admitted to our hospital due to neck-scar contracture after a chemical burn 3 years previously. During surgery, the scar was resected above the platysma. A large, 19 × 6-cm skin-pedicled flap was elevated from the left pectoral area. We planned to supercharge the flap by anastomosing the second intercostal perforator to the flap periphery but could not confirm the perforator intraoperatively. To promote flap survival, we did not elevate the flap pedicle more than absolutely necessary and then manipulated the flap very carefully. The flap survived fully and the contracture was effectively released. Thin flaps are useful for reconstructing exposed areas such as the face, neck, and dorsum of the hands that require good outcomes in terms of both function and aesthetics. However, if the flap is too large, ischemia/congestion could arise in the periphery unless the blood flow is stabilized by attaching a perforator. In our case, supercharging was not possible and we had to resort to careful intraoperative maneuvers to ensure flap survival. This approach was successful and suggests that although supercharging of thin and large flaps is preferred, unexpectedly unsuperchargeable flaps can be rescued by careful and finely tuned surgical judgment and techniques.

The Latest Strategy for Keloid and Hypertrophic Scar Prevention and Treatment: The Nippon Medical School (NMS) Protocol.

In 2006, we established a scar/keloid-specialized unit in the Department of Plastic, Reconstructive, and Aesthetic Surgery at Nippon Medical School (NMS) in Tokyo, Japan. In the ensuing 15 years, we treated approximately 2,000 new scar/keloid patients annually. This extensive experience has greatly improved the efficacy of the treatments we offer. Therefore, we discuss here the latest NMS protocol for preventing and treating keloids and hypertrophic scars. While this protocol was optimized for Japanese patients, our experience with a growing body of non-Japanese patients suggests that it is also effective in other ethnicities. The extensive evidence-based experience underlying the NMS protocol suggests that it may be suitable as the foundation of a standard international prevention/treatment algorithm for pathological scars.

Combination Therapy Composed of Surgery, Postoperative Radiotherapy, and Wound Self-management for Umbilical Keloids.

BACKGROUND: A universally accepted therapeutic strategy for umbilical keloids has not been determined. Our team has had considerable success with combination therapy composed of surgical excision followed by postoperative radiotherapy and steroid plaster/injection. METHODS: All consecutive patients with umbilical keloids that developed from endoscopic surgical scars and underwent minimal-margin keloid excision followed by umbilicoplasty with a flap if needed, tension-reduction suturing, and postoperative radiotherapy in 2013-2017 in the keloid/scar-specialized clinic at the Department of Plastic, Reconstructive and Aesthetic Surgery of Nippon Medical School. The postsurgical radiotherapy regimen was 15 Gy administered in 2 fractions over 2 consecutive days. Radiotherapy was followed by tension-reducing wound self-management with silicone tape or, if needed, steroid plaster. The primary study focus was keloid recurrence during the 24-month follow-up period. Recurrence was defined as the growth of stiff red lesions in even small areas of the scar that was refractory to 2-6 months of steroid-plaster therapy. RESULTS: The case series consisted of 34 patients with 34 lesions. Three lesions (8.8%) recurred. One recurrence was successfully treated by concomitant steroid plaster/injection. The other 2 cases were resistant to steroid injection and underwent reoperation without radiotherapy followed by 6 months of steroid-plaster therapy. None of the 3 cases recurred within 2 years of steroid plaster/injection completion or reoperation. CONCLUSION: Umbilical keloids can be successfully treated by customized treatment plans that involve appropriate surgical modalities (including umbilicoplasty, if required), postoperative radiotherapy (15 Gy/2 fractions/2 days), and wound/scar self-management with silicone tape and steroid plaster.

Direct Delivery of Apatite Nanoparticle-Encapsulated siRNA Targeting TIMP-1 for Intractable Abnormal Scars.

Hypertrophic scars (HSs) and keloids are histologically characterized by excessive extracellular matrix (ECM) deposition. ECM deposition depends on the balance between matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteases (TIMPs). TIMP-1 has been linked to ECM degradation and is therefore a promising therapeutic strategy. In this study, we generated super carbonate apatite (sCA) nanoparticle-encapsulated TIMP-1 small interfering RNA (siRNA) (siTIMP1) preparations and examined the effect of local injections on mouse HSs and on ex vivo-cultured keloids. The sCA-siTIMP1 injections significantly reduced scar formation, scar cross-sectional areas, collagen densities, and collagen types I and III levels in the lesions. None of the mice died or exhibited abnormal endpoints. Apatite accumulation was not detected in the other organs. In an ex vivo keloid tissue culture system, sCA-siTIMP1 injections reduced the thickness and complexity of collagen bundles. Our results showed that topical sCA-siTIMP1 injections during mechanical stress-induced HS development reduced scar size. When keloids were injected three times with sCA-siTIMP1 during 6 days, keloidal collagen levels decreased substantially. Accordingly, sCA-siRNA delivery may be an effective approach for keloid treatment, and further investigations are needed to enable its practical use.

Gene Expression Profile of Isolated Dermal Vascular Endothelial Cells in Keloids.

Wound healing is a complex biological process, and imbalances of various substances in the wound environment may prolong healing and lead to excessive scarring. Keloid is abnormal proliferation of scar tissue beyond the original wound margins with excessive deposition of extracellular matrix (ECM) and chronic inflammation. Despite numerous previous research efforts, the pathogenesis of keloid remains unknown. Vascular endothelial cells (VECs) are a major type of inductive cell in inflammation and fibrosis. Despite several studies on vascular morphology in keloid formation, there has been no functional analysis of the role of VECs. In the present study, we isolated living VECs from keloid tissues and investigated gene expression patterns using microarray analysis. We obtained 5 keloid tissue samples and 6 normal skin samples from patients without keloid. Immediately after excision, tissue samples were gently minced and living cells were isolated. Magnetic-activated cell sorting of VECs was performed by negative selection of fibroblasts and CD45+ cells and by positive selection of CD31+cells. After RNA extraction, gene expression analysis was performed to compare VECs isolated from keloid tissue (KVECs) with VECs from normal skin (NVECs). After cell isolation, the percentage of CD31+ cells as measured by flow cytometry ranged from 81.8%-98.6%. Principal component analysis was used to identify distinct molecular phenotypes in KVECs versus NVECs and these were divided into two subgroups. In total, 15 genes were upregulated, and 3 genes were downregulated in KVECs compared with NVECs using the t-test (< 0.05). Quantitative RT-PCR and immunohistochemistry showed 16-fold and 11-fold overexpression of SERPINA3 and LAMC2, respectively. SERPINA3 encodes the serine protease inhibitor, α1-antichymotripsin. Laminin γ2-Chain (LAMC2) is a subunit of laminin-5 that induces retraction of vascular endothelial cells and enhances vascular permeability. This is the first report of VEC isolation and gene expression analysis in keloid tissue. Our data suggest that SERPINA3 and LAMC2 upregulation in KVECs may contribute to the development of fibrosis and prolonged inflammation in keloid. Further functional investigation of these genes will help clarify the mechanisms of abnormal scar tissue proliferation.