Increased blood flow in keloids and adjacent skin revealed by laser speckle contrast imaging

A preliminary study on ultrasound techniques applied to evaluate the curative effect of botulinum toxin type a in hypertrophic scars

Objective

To validate the feasibility of ultrasound in assessing the curative effect of botulinum toxin type A (BTXA) in treating hypertrophic scar (HS).

Methods

Eight healthy New Zealand long-eared rabbits were utilized in the study. Four wounds, each measuring 1.0 cm in diameter, were created on both ears of each rabbit. Immediately after surgery, each of these wounds received an injection containing a distinct concentration of BTXA. On postoperative week 6, scar thickness, vascularity, and hardness were assessed based on high frequency ultrasound (HFUS), superb microvascular imaging (SMI), shear wave elastography (SWE), Masson staining, and immunohistochemical staining for CD31.

Results

All wounds healed well, and HSs formed after 6 weeks post-surgery. Scar thickness based on HFUS presented a significant decrease with increasing BTXA concentration (p < 0.05), aligning with the gross morphology. Simultaneously, scar stiffness, evaluated using SWE, showed a significant decrease in accordance with the variation of the collagen volume fraction, which refers to the ratio of the collagen positive area to the total area (p < 0.05). Although the vascularity index obtained by SMI did not exhibit a statistically significant change across different BTXA concentrations, this technique effectively illustrated the microvascular perfusion in HS. Immunohistochemical staining for CD31 revealed that BTXA inhibited angiogenesis.

Conclusion

HFUS and SWE displayed excellent performance in evaluating HS thickness and stiffness. SMI showed a good performance in reflecting microvascular signals in HS. These ultrasound techniques have great potential in assessing the therapeutic effect of BTXA in HS.

Dual-wavelength dye laser combined with betamethasone injection for treatment of keloids: protocol of a randomised controlled trial

INTRODUCTION

Keloids, benign fibroproliferative tumours characterised by excessive fibroblast proliferation and over-deposition of extracellular matrix, pose a therapeutic challenge with high recurrence rates. Betamethasone (diprospan) injection (BI) is one of the most common non-invasive therapies for keloids. Pulsed dye laser (PDL) has the function of closing microvessels, which may become one of the auxiliary treatment methods of BI and may enhance its curative effect. Some studies suggest that the combination of a dual-wavelength dye laser (DWL) and BI may offer superior efficacy. This randomised controlled trial aims to evaluate whether the combined therapy of DWL+BI outperforms BI alone in treating keloids.

METHODS AND ANALYSIS

This single-centre, parallel positive control, randomised trial evaluates the efficacy and safety of DWL (585 nm PDL+1064 nm neodymium-doped yttrium aluminium garnet) combined with BI for keloid treatment. Enrolling 66 adult patients, participants are randomised into DWL+BI or BI groups in a 1:1 ratio. Over 12 weeks, each group undergoes four treatment sessions, ensuring blinding for outcome assessors. Data collection occurs at multiple time points (4, 12, 24 and 52 weeks), with primary outcomes assessing the Vancouver Scar Scale (VSS) improvement rate 24 weeks after the last intervention. Secondary outcomes include VSS improvement rates, changes in keloid volume, changes in relative perfusion index measured by laser speckle contrast imaging, Patient and Observer Scar Assessment Scale results and patient satisfaction. Safety assessments include vital signs, laboratory tests, pregnancy tests and self-reports of adverse reactions.

ETHICS AND DISSEMINATION

The results will be presented in peer-reviewed journals and at international conferences. This study is approved by the Ethics Committee of Peking Union Medical College Hospital, Chinese Academy of Medical Sciences.

TRIAL REGISTRATION NUMBER

Chinese Clinical Trial Register (ChiCTR2400080148).

Development and validation of novel keloid-derived immortalized fibroblast cell lines

Keloids are a common connective tissue disorder with an ill-understood etiopathogenesis and no effective treatment. This is exacerbated because of the absence of an animal model. Patient-derived primary keloid cells are insufficient as they age through passaging and have a limited supply. Therefore, there is an unmet need for development of a cellular model that can consistently and faithfully represent keloid's pathognomic features. In view of this, we developed keloid-derived immortalized fibroblast (KDIF) cell lines from primary keloid fibroblasts (PKF) by transfecting the human telomerase reverse transcriptase (hTERT) gene. The TERT gene encodes the catalytic subunit of the telomerase enzyme, which is responsible for maintaining the cellular replicative potential (cellular immortalization). Primary fibroblasts from keloid-specific lesional (peripheral, middle, and top) as well as extralesional sites were isolated and evaluated for cell line development and comparative cellular characteristics by employing qRT-PCR and immunofluorescence staining. Moreover, the immortalized behavior of KDIF cell lines was evaluated by comparing with cutaneous fibrosarcoma and dermatofibrosarcoma protuberans cell lines. Stable KDIF cell lines with elevated expression of hTERT exhibited the cellular characteristics of site-specific keloid fibroblasts. Histochemical staining for β-galactosidase revealed a significantly lower number of β-gal-positive cells in all three KDIF cell lines compared with that in PKFs. The cell growth curve pattern was studied over 10 passages for all three KDIF cell lines and was compared with the control groups. The results showed that all three KDIF cell lines grew significantly faster and obtained a fast growing characteristic as compared to primary keloid and normal fibroblasts. Phenotypic behavior in growth potential is an indication of hTERT-mediated immortalized transformation. Cell migration analysis revealed that the top and middle KDIF cell lines exhibited similar migration trend as site-specific PKFs. Notably, peripheral KDIF cell line showed significantly enhanced cell migration in comparison to the primary peripheral fibroblasts. All KDIF cell lines expressed Collagen I protein as a keloid-associated fibrotic marker. Functional testing with triamcinolone inhibited cell migration in KDIF. ATCC short tandem repeat profiling validated the KDIF as keloid representative cell line. In summary, we provide the first novel KDIF cell lines. These cell lines overcome the limitations related to primary cell passaging and tissue supply due to immortalized features and present an accessible and consistent experimental model for keloid research.

Re-recognition of the role of roughness in keloid assessment

BACKGROUND

Under visual observation, keloids are more rough than normal skin. This roughness may be used to assess the activity and severity of keloids but lacks the support of objective and accurate evidence. The purpose of this study was to verify the role of roughness in the development of keloids and to clarify the advantage of roughness in the comprehensive assessment of keloids.

METHODS

Patients with keloids who attended Peking Union Medical College Hospital were recruited. Keloids were classified into progressive, stable, and atrophic stages based on the change in size over the past year and blood perfusion. The keloids were evaluated using the Vancouver Scar Scale (VSS) and the Patient and Observer Scar Assessment Scale (POSAS). The roughnesses of the keloid and normal skin were measured using the Phaseshift Rapid In vivo Measurement Of the Skin (PRIMOS), and blood perfusion was measured using laser speckle contrast imaging (LSCI).

RESULTS

Thirty-three patients with a total of 81 keloids were included. The surface roughness values Sa, Sq, and Sz of the keloid region were 243.70 (143.85-328.05), 316.20 (179.85-475.20), and 1708.20 (1098.30-4087.20), respectively, which were 4.87, 4.80, and 3.08 times higher than those of normal skin. There were significant differences in roughness among the different keloid stages. A significantly strong correlation between roughness and other assessed indices was found.

CONCLUSIONS

Roughness as a morphological characteristic is of great value in the evaluation of keloids. It is recommended as an important examination for keloids.

68 Ga-FAPI-04 PET/CT in Assessment of Fibroblast Activation in Keloids : A Prospective Pilot Study

PURPOSE

Keloids are benign fibroproliferative disorders characterized by the massive proliferation of fibroblasts. Fibroblast activation plays a key role in the invasive growth of keloids. Therefore, a prospective pilot study was conducted to explore the value of 68 Ga-FAPI-04 PET/CT in the assessment of keloids activity.

PATIENTS AND METHODS

Twenty-five patients with keloid were enrolled to conduct 68 Ga-FAPI-04 PET/CT. All patients accepted surgery to remove part of the lesions within 1 week. SUV mean and SUV max were measured for semiquantitative analysis and compared with the Vancouver Scar Scale, Laser Speckle Contrast Imaging, pathology, and immunohistochemical stains.

RESULTS

A total of 123 lesions were detected in 25 patients, most of which were distributed in the anterior chest wall. The 68 Ga-FAPI-04 uptake was significantly different at different sites ( P < 0.0001). There was uptake heterogeneity within the keloid lesions, and a significant difference was found between the edge and center of some large lesions. The SUV max of 68 Ga-FAPI-04 showed significantly correlation with the Vancouver Scar Scale ( r = 0.565, P < 0.0001) moderately and the Laser Speckle Contrast Imaging parameters mildly. The SUV max of 68 Ga-FAPI-04 had a moderate correlation with FAPI expression ( r = 0.520, P = 0.022). Moreover, collagen, fibroblast activator protein, and Ki-67 expression were found higher at the edges of keloid tissue than in the center.

CONCLUSIONS

68 Ga-FAPI-04 PET/CT can reflect the distribution characteristics of activated fibroblasts in keloid tissue and may provide a novel method for keloid evaluation for further fibroblast-related therapies.

Influence of Moisturizers on Skin Microcirculation: An Assessment Study Using Laser Speckle Contrast Imaging

Non-invasive scar management typically involves pressure therapy, hydration with silicones or moisturizers, and UV protection. Moisture loss from scars can lead to hypertrophic scar formation. Pressure therapy reduces blood flow, fibroblast activity, and transforming growth factor beta 1 (TGF-β1) release. This study examined various moisturizers and liquid silicone gel's impact on microcirculation. 40 volunteers participated in a study where superficial abrasions were created to induce trans epidermal water loss (TEWL). Five moisturizers (TEDRA®, TEDRA® NT1, TEDRA® NT3, Alhydran®, Lipikar®) and BAP Scar Care® silicone gel were tested. TEWL, hydration, and blood flow were measured up to 4 h post-application. Results showed that silicone had the least impact on occlusion and hydration. Alhydran® reduced blood flow the most, while Lipikar® increased it the most. TEDRA® NT1 had reduced flow compared to TEDRA® and TEDRA® NT3. All TEDRA® products exhibited high hydration, and all but silicone showed good occlusion. Moisturizers influenced skin microcirculation, with some causing decrease, while others increased flow. However, the clinical impact on scarring remains unclear compared to the evident effects of hydration and occlusion. More research is necessary to study moisturizers alone and with pressure therapy on scars, along with potential adverse effects of increased microcirculation on scars.

Applications of Laser Speckle Contrast Imaging Technology in Dermatology

Laser speckle contrast imaging or laser speckle imaging (LSI) is a noninvasive imaging technology that can detect areas of dynamic perfusion or vascular flow. Thus, LSI has shown increasing diagnostic utility in various pathologies and has been employed for intraoperative, postoperative, and long-term monitoring in many medical specialties. Recently, LSI has gained traction in clinical dermatology because it can be effective in the assessment of pathologies that are associated with increased perfusion and hypervascularity compared with that of normal tissue. To date, LSI has been found to be highly accurate in monitoring skin graft reperfusion, determining the severity of burns, evaluating neurosurgical revascularization, assessing persistent perfusion in capillary malformations after laser therapy, and differentiating malignant and benign skin lesions. LSI affords the advantage of noninvasively assessing lesions before more invasive methods of diagnosis, such as tissue biopsy, while remaining inexpensive and exhibiting no adverse events to date. However, potential obstacles to its clinical use include tissue movement artifact, primarily qualitative data, and unclear impact on clinical practice given the lack of superiority data compared with the current standard-of-care diagnostic methods. In this review, we discuss the clinical applications of LSI in dermatology for use in the diagnosis and monitoring of vascular, neoplastic, and inflammatory skin conditions.

The Efficacy of Intense Pulsed Light in the Treatment of Keloids and Hypertrophic Scars

Introduction: Different therapies have been applied to keloids and hypertrophic scars. Intense pulsed light (IPL) has recently been used but the evidence is limited. This study was to evaluate the effectiveness and safety of IPL as monotherapy for keloids and hypertrophic scars. Methods: This was a before-and-after interventional study on 16 patients with 50 scars who underwent IPL. Seven scars receive one IPL session, seven received two sessions, and 36 received three sessions. Outcomes were evaluated by the Vancouver Scar Scale (VSS), Patient and Observer Scar Assessment Scale (POSAS), scar ultrasound, colorimeter for pigmentation and erythema, and side effects. Results: After the treatment, most outcomes significantly improved except that the pigmentation of the scars did not change. Scar thickness significantly reduced by nearly 10% after the first IPL session, 15% after the second session, and>20% after the third session. All side effects were mild with crust (33.3-46%), blisters (8.3-40%), and hyperpigmentation around the scar (0-14%); the pain was moderate as assessed by the patients. Conclusion: IPL is a safe and effective treatment for keloids and hypertrophic scars. More studies are required to confirm our results.

Role of HIF-1α in pathogenic mechanisms of keloids

BACKGROUDS AND OBJECTIVE

Keloids are defined as overrepairing products that develop after skin lesions. Keloids are characterized by the proliferation of fibroblasts and the overaccumulation of extracellular matrix components (mainly collagen), leading to a locally hypoxic microenvironment. Hence, this article was aimed to review hypoxia in pathogenesis of keloids.

METHODS

We reviewed and summarized the relevant published studies.

RESULTS

Hypoxia results in the accumulation of hypoxia-inducible factor 1α (HIF-1α) in keloids, contributing to overactivation of the fibrotic signaling pathway, epithelial-mesenchymal transition, and changes in metabolism, eventually leading to aggravated fibrosis, infiltrative growth, and radiotherapy resistance.

CONCLUSION

It is, therefore, essential to understand the role of HIF-1α in the pathogenic mechanisms of keloids in order to develop new therapeutic approaches.

Skin endothelial cell and microcirculation function study in recurred keloids patients after keloid surgery and radiotherapy

BACKGROUND

Keloid is a type of benign tumor of the skin with abnormal proliferation of fibrous tissue. We sought to observe the changes in skin microcirculation and endothelial cell function around the recurred keloid and explore the skin microcirculation characters in recurred keloid patients.

METHODS

Six patients with recurred keloid were treated with keloid surgery and radiotherapy for the second time. Microcirculation of recurred keloids and their surrounding normal skin tissue was observed with laser Doppler flowmeter before operation. Expression of vascular endothelial growth factor (VEGF), CD31, and HIF-1α were identified by several assay.

RESULTS

The local blood flow of group RN was enhanced. The average strength of group N is 0.87. The average strength of group RN is 2.08. The expression of VEGF, CD31, and hypoxia inducible factor-1α (HIF-1α) protein in the keloid-recurred skin (RN) group was higher than the normal skin group via immunohistochemistry (IHC) and Western blotting analysis. The relative expression of VEGF and CD31 mRNA was significantly increased in RN group samples (P < .05).

CONCLUSIONS

There are significant differences in the expression of VEGF, CD31, and HIF-1α in the recurred keloid skin after radiotherapy and normal skin. They may be used as potential biomarkers and targets for future research on keloid recurrence.

Relative perfusion index: An objective, quantitative and noninvasive method for evaluating the severity of keloids

BACKGROUND

Keloids are the result of abnormal wound healing, and they differ from the normal skin of the patient in the level of blood perfusion and the degrees of inflammation, hypoxia, regeneration of vessels, and expression of sensory receptors. However, there is no objective assessment method to accurately characterize the severity of keloids.

OBJECTIVES

The purpose of this study was to evaluate the perfusion levels of keloids and the expression levels of various internal cytokines, including hypoxia-induced factor-1α (HIF-1α), vascular endothelial growth factor (VEGF), interleukin-17 (IL-17), HT_2A receptor subtype (5-HT_2A R), and H1R, in keloids and nonadjacent normal skin and to propose a laser speckle contrast imaging (LSCI)-based relative perfusion index (RPI), through which keloids can be divided into five grades to objectively characterize their severity.

METHODS

This population-based cross-sectional study included 70 untreated keloid patients who each had only one keloid on the chest. LSCI was used to measure the area of each patient's keloid ( K area ${K}_{\mathrm{area}}$ ) and the perfusion level of each patient's keloid ( K perfusion ${K}_{\mathrm{perfusion}}$ ) and normal skin ( N perfusion ${N}_{\mathrm{perfusion}}$ ). The Vancouver Scar Scale (VSS) and Visual Analog Scale (VAS) for pain and pruritus were also used to assess each keloid. Immunohistochemistry and Western blot were used to detect the expression levels of various internal cytokines in keloids and normal skin. We compared the perfusion and expression levels of intrinsic cytokines between keloids and normal skin. We established the RPI to grade the severity of keloids and applied different methods to test the utility of the RPI.

RESULTS

The mean perfusion level of keloids was significantly higher than that of normal skin (p < 0.001). The expression levels of HIF-1α, VEGF, IL-17, 5-HT_2A R, and H1R in keloids were significantly higher than those in normal skin (p < 0.05). RPI was defined as: [ ( K perfusion - N perfusion ) × 0.03 + K area × 0.001 ] . $[({K}_{\mathrm{perfusion}}-{N}_{\mathrm{perfusion}})\times 0.03+{K}_{\mathrm{area}}\times 0.001].$ The severity of keloids could be divided into five grades based on RPI. The RPI had a higher correlation with the pain-VAS, pruritus-VAS, and the expression levels of internal cytokines in keloids than blood perfusion levels and the VSS. T-SNE (t-distributed stochastic neighbor embedding) was also used to verify the clinical discriminatory abilities of this RPI model.

CONCLUSIONS

The proposed RPI based on LSCI showed the highest accuracy, unlike the VSS and assessment of perfusion, and can be utilized as a reliable, objective, quantitative, and noninvasive tool to evaluate the severity of keloids.

A Workflow for Computer-Aided Evaluation of Keloid Based on Laser Speckle Contrast Imaging and Deep Learning

A keloid results from abnormal wound healing, which has different blood perfusion and growth states among patients. Active monitoring and treatment of actively growing keloids at the initial stage can effectively inhibit keloid enlargement and has important medical and aesthetic implications. LSCI (laser speckle contrast imaging) has been developed to obtain the blood perfusion of the keloid and shows a high relationship with the severity and prognosis. However, the LSCI-based method requires manual annotation and evaluation of the keloid, which is time consuming. Although many studies have designed deep-learning networks for the detection and classification of skin lesions, there are still challenges to the assessment of keloid growth status, especially based on small samples. This retrospective study included 150 untreated keloid patients, intensity images, and blood perfusion images obtained from LSCI. A newly proposed workflow based on cascaded vision transformer architecture was proposed, reaching a dice coefficient value of 0.895 for keloid segmentation by 2% improvement, an error of 8.6 ± 5.4 perfusion units, and a relative error of 7.8% ± 6.6% for blood calculation, and an accuracy of 0.927 for growth state prediction by 1.4% improvement than baseline.

Histology and Vascular Architecture Study of Keloid Tissue to Outline the Possible Terminology of Keloid Skin Flaps

BACKGROUND

Using the keloid "epidermis" to cover a wound is widely used during treatment for keloids. Many flap terminologies have been used in literature. However, the definition of the flap is not well established. Here, we refined the definition of the flap and associated terminology and explored the survival mechanism of the 'flap' through histological analysis and blood supply studying.

METHODS

Histology and vascular study of keloid was carried out with keloid and its surrounding normal skin tissue which were collected from keloid patients following keloid resection operations. The histological structures and thicknesses of epidermal and subepidermal of the keloids were analyzed and measured using hematoxylin & eosin (H&E) staining. Vascular density and blood perfusion in the subepidermal layer of keloids (KDS) were analyzed using CD31 immunohistochemical staining and a laser speckle contrast imaging system (LSCI), respectively. The vascular network in KDS was visualized by CD31 immunofluorescence staining and three-dimensional reconstruction.

RESULTS

29 pieces of keloid and its surrounding normal skin tissue sample from ten patients were collected. Keloid samples were about 2 cm wide and 5 cm long. The normal skin samples were about 2 to 3 mm in width. The thickness of epidermal layer of keloids was (136.4 ± 35.3) μm, and the thickness of epidermal layer of surrounding normal skin was (78.8 ± 13.9) μm. There was statistical thickness difference between the two layers, t(20) = 7.469, P < 0.001. The total thickness of keloid epidermal and subepidermal layers was 391.4 ± 2.3 μm. The vascular density (13.9 ± 3.4/field) and blood flow perfusion (132.7 ± 31.3) PU in KDS were greater than that of surrounding normal skin (7.8 ± 2.3/field, 73.9 ± 17.9 PU), P < 0.001. Horizontally distributed vessels with several vertical branches were observed in 3D vascular network reconstruction.

CONCLUSION

The epidermal layer of keloid is thicker than that of surrounding normal skin. There is a vascular network structure under it. The vessels mainly locate at a depth of about 150 to 400 μm from the surface of keloid epidermis, randomly distribute and run parallel to the epidermis. Based on these characteristics which may ensure an adequate blood supply, we propose the concept of a "keloid subepidermal vascular network flap."

LEVEL OF EVIDENCE V

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 .

Clinical Observation of Subepidermal Vascular Network Flaps in Keloid Patients

BACKGROUND

There are many different keloid treatment modalities. One surgical technique is to keep the "shell" of the keloid to cover the defect. We named this "shell" keloid subepidermal vascular network flap (KSVNF), and we outlined the characteristics of this flap by observing 35 flaps in keloid patients.

METHODS

A total of 35 KSVNFs were designed in 15 patients during 2020-2021. All patients underwent the operation and adjuvant radiotherapy as well as hyperbaric oxygen therapy. All flap lengths and widths were recorded, and the blood perfusion of the flaps was measured on the first day postoperation and the day of stitch removal. Flap survival and the quality of flaps were evaluated on the day of stitch removal. All harvested data were analyzed using the R (version 4.0.1) package.

RESULTS

The mean blood perfusion on the first day postoperation (pod1) and the day of stitch removal was 120.4013 and 168.6900, respectively (p = 0.02249); 2 flaps had partial necrosis (5.714%). Receiver operating characteristic (ROC) curve analysis showed that when the length/width ratio was less than 1.05, the quality of the flap was good (AUC = 0.724), which suggests that the effective safe length/width ratio was 1.05.

CONCLUSION

KSVNF is an applicable method for covering the remaining wound after keloid mass removal with sufficient blood perfusion and adequate skin quality. We recommend that the length/width ratio of the flap design not exceed 1.

LEVEL OF EVIDENCE IV

This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes Review Articles, Book Reviews, and manuscripts that concern Basic Science, Animal Studies, Cadaver Studies, and Experimental Studies. 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 .

Activity of keloids evaluated by multimodal photoacoustic/ultrasonic imaging system

Multiple objective assessments have been used to assess the activity of keloids to compare different therapeutic regimens and facilitate the best individual treatment choice for patients, but none of them are standardized. A multimodal photoacoustic/ultrasonic (PA/US) imaging system, including photoacoustic imaging, elastography, ultra-micro-angiography, and conventional US technologies (gray scale US, color Doppler US, and power Doppler US), was applied to evaluate keloids by a radiologist. Growing stages were defined by patients, and Vancouver Scar Scale (VSS) was assessed by a plastic surgeon. A comprehensive model based on multimodal ultrasound parameters (poor-echo pattern, high vascular density, decreased elasticity, and low SO₂ within the keloid) and VSS might be a potential indicator of active keloids, comparing with VSS alone. The multimodal PA/US imaging system could be a promising technique for keloids assessment.

Laser Speckle Contrast Imaging for the Objective Assessment of Blood Perfusion in Keloids Treated With Dual-Wavelength Laser Therapy

BACKGROUND

Most of the widely used methods for the assessment of keloid treatment are subjective grading scales based on the opinion of an individual clinician or patient. There is a growing need for objective methods to evaluate keloid treatment.

OBJECTIVE

This study aimed to evaluate the value of laser speckle contrast imaging (LSCI) as an objective method for the assessment of dual-wavelength laser therapy for keloids.

METHODS

This prospective study included 21 patients with 54 keloids. All patients were treated with a combined 585-nm pulsed dye laser and 1,064 nm neodymium-doped yttrium aluminum garnet dual-wavelength laser at 4 weeks to 6 weeks intervals. Keloids were assessed using the Vancouver Scar Scale (VSS) and LSCI.

RESULTS

The total VSS score significantly decreased after 4 sessions of treatment (p < .05). Blood perfusion in keloids as measured by LSCI was significantly reduced after treatment (p < .05). The improvement of chest keloids in terms of the total VSS score and blood perfusion was significantly greater than that of scapular keloids (p < .05). There was a positive correlation between decreased perfusion and reduced total VSS score (R2 = 0.84).

CONCLUSION

Blood perfusion in keloids significantly decreased after dual-wavelength laser therapy. Laser speckle contrast imaging is a promising objective method for assessing the improvement of keloids treated with laser therapy.

The epigenetics of keloids

Keloid scarring is a fibroproliferative disorder of the skin with unknown pathophysiology, characterised by fibrotic tissue that extends beyond the boundaries of the original wound. Therapeutic options are few and commonly ineffective, with keloids very commonly recurring even after surgery and adjunct treatments. Epigenetics, defined as alterations to the DNA not involving the base-pair sequence, is a key regulator of cell functions, and aberrant epigenetic modifications have been found to contribute to many pathologies. Multiple studies have examined many different epigenetic modifications in keloids, including DNA methylation, histone modification, microRNAs and long non-coding RNAs. These studies have established that epigenetic dysregulation exists in keloid scars, and successful future treatment of keloids may involve reverting these aberrant modifications back to those found in normal skin. Here we summarise the clinical and experimental studies available on the epigenetics of keloids, discuss the major open questions and future perspectives on the treatment of this disease.

Different Types of Auricular Keloids and Treatment by Intralesional Cryosurgery: Best Practice for Obtaining Long-Lasting Clinical Results

BACKGROUND

Auricular keloids belong to the most perplexing medical conditions, which have significant psychosocial impact on the patient's body image and quality of life.

SUMMARY

The article is purposed to provide dermatologists and plastic surgeons with the best proven practice using intralesional cryosurgery for the treatment of the different auricular keloid types in order to obtain superior clinical results by minimizing the probability of recurrence. In the past 20 years, the authors have developed novel procedures in order to increase the effectiveness of intralesional cryosurgery on auricular keloids, including hydrodissection, warm gauze technique, and excision of dangling skin. Long-lasting clinical results with a low recurrence rate and a satisfactory aesthetic outcome are achieved with no deformation of the ear framework.

Revisiting the vascularity of the keratinized gingiva in the maxillary esthetic zone

Background

The active arterial-to-arterial collaterals are a significant factor in the prevention of ischemia and extensive tissue necrosis in the case of arterial blockage of various tissues. The present study investigates the mucogingival vasculature in the maxillary esthetic zone mucosa in human cadavers and functionally evaluates the area, which is supplied by the terminal arterioles, on the individual level.

Methods

In the human cadaver study, macroscopic arterial analyses of the anterior maxillary vestibule in 7 specimens were scrutinized by latex milk injection. The tracks of the mucosal branches in relation to the mucogingival junction were investigated. In the functional study, individual gingival blood flow (GBF) changes were measured by laser speckle contrast imaging (LSCI) in 31 young subjects with healthy gingiva before and during 30-s compressions. This was conducted with a ball-shaped condenser. The data was analyzed by the linear mixed model.

Results

The vertically aligned branches of the superior labial artery (SLA) divided into small, slightly deviating sub-branches near the mucogingival junction. These arteries created collateral plexuses and supplied the attached gingiva. The compression of these branches resulted in ischemia coronally with significant individual variation. The ischemia was either apico-mesial, apico-distal, or straight apical to the compression. A significant correlation was found between the ischemic area and the magnitude of the decrease in GBF (r = 0.81, p < 0.001). In males, 77% of the subjects, and 50% of the female subjects had an ischemic response in either region. The horizontal extension of the ischemic area ranged between 0.26 mm and 8.76 mm. Males had significantly higher baseline GBF and larger ischemia than females. At the base of the papilla, significant restoration of GBF was observed during compression in males, but not in females.

Conclusion

The arcade anastomoses formed by the small arteries in the keratinized gingiva of the upper esthetic zone explain the consequences of vertical incisions. The considerable individual variations in ischemic responses might be the reason for unexpected surgical outcomes in some cases. Furthermore, there is increasing evidence that men have different vascular reactivity and/or regulation of collateral circulation than women, which may affect wound healing.

Blood perfusion in hypertrophic scars and keloids studied by laser speckle contrast imaging

BACKGROUND

This study used laser speckle contrast imaging (LSCI) to evaluate the difference in blood perfusion between hypertrophic scars and keloids.

MATERIALS AND METHODS

A total of 30 keloids, 21 early hypertrophic scars, 20 proliferative hypertrophic scars, 20 regressive hypertrophic scars, and 20 mature hypertrophic scars were enrolled into this study. Vancouver Scar Scale (VSS) was assessed by a plastic surgeon. LSCI was used to evaluate perfusion of the whole (W), marginal (M), central (C) regions, and surrounding normal skin of the scars, and ratios (M/N, C/N) were calculated.

RESULTS

The perfusion of the marginal region in the keloid was significantly higher than that of the central region. Nevertheless, there was no significant difference in perfusion between the central and marginal regions in the early, proliferative, regressive, and mature hypertrophic scars. The degree of perfusion and perfusion ratio in the marginal region of keloid was similar to that of proliferative hypertrophic scars, and the degree of perfusion and perfusion ratio in central region of keloid group was similar to that of early and regressive hypertrophic scars.

CONCLUSIONS

The difference in perfusion distribution in keloids and hypertrophic scars may provide ideas for their identification. LSCI may be a useful method for differentiating between keloids and hypertrophic scars.

Heterogeneous Features of Keloids Assessed by Laser Speckle Contrast Imaging: A Cross-Sectional Study

BACKGROUND AND OBJECTIVES

Keloids are described as benign dermal fibroproliferative lesions, and vascularization may play a significant role in their pathogenesis. In this study, laser speckle contrast imaging (LSCI) was used to assess perfusion within keloids and surrounding skin, and perfusion of keloids at different stages was compared.

STUDY DESIGN/MATERIALS AND METHODS

A total of 59 patients with 110 untreated keloids on the anterior chest were enrolled in this study. Different keloid stages (progressive, stable, and regressive) were defined according to patients' descriptions of whether keloids became larger, stable, or smaller during the previous year. Vancouver Scar Scale (VSS) was assessed by a plastic surgeon, and patient reports on pain and itching were documented. LSCI was used to evaluate blood perfusion of keloids (K), skin adjacent to keloids (A), and nonadjacent skin (N). The mean perfusion of these regions was determined, and ratios (K/N, A/N) were calculated.

RESULTS

A heterogeneous perfusion map was observed among the keloid groups, as well as within each keloid. A positive correlation was found between keloid perfusion and VSS. There were 62 (56.4%) keloids in the progressive stage, 33 (30.0%) keloids in the stable stage, and 15 (13.6%) keloids in the regressive stage. The mean K/N ratios in the progressive, stable, and regressive stages were 2.3 ± 0.5, 1.8 ± 0.3, and 1.5 ± 0.5, respectively. The mean A/N ratios were 1.2 ± 0.4, 1.2 ± 0.2, and 1.0 ± 0.5, respectively. Within each keloid, significantly higher perfusion was noted in the keloid and adjacent skin compared with nonadjacent skin.

CONCLUSION

These results indicate that LSCI is a promising technique for evaluating keloid blood perfusion and distinguishing heterogeneous keloids. Lasers Surg. Med. © 2020 Wiley Periodicals LLC.

The Keloid Disorder: Heterogeneity, Histopathology, Mechanisms and Models

Keloids constitute an abnormal fibroproliferative wound healing response in which raised scar tissue grows excessively and invasively beyond the original wound borders. This review provides a comprehensive overview of several important themes in keloid research: namely keloid histopathology, heterogeneity, pathogenesis, and model systems. Although keloidal collagen versus nodules and α-SMA-immunoreactivity have been considered pathognomonic for keloids versus hypertrophic scars, conflicting results have been reported which will be discussed together with other histopathological keloid characteristics. Importantly, histopathological keloid abnormalities are also present in the keloid epidermis. Heterogeneity between and within keloids exists which is often not considered when interpreting results and may explain discrepancies between studies. At least two distinct keloid phenotypes exist, the superficial-spreading/flat keloids and the bulging/raised keloids. Within keloids, the periphery is often seen as the actively growing margin compared to the more quiescent center, although the opposite has also been reported. Interestingly, the normal skin directly surrounding keloids also shows partial keloid characteristics. Keloids are most likely to occur after an inciting stimulus such as (minor and disproportionate) dermal injury or an inflammatory process (environmental factors) at a keloid-prone anatomical site (topological factors) in a genetically predisposed individual (patient-related factors). The specific cellular abnormalities these various patient, topological and environmental factors generate to ultimately result in keloid scar formation are discussed. Existing keloid models can largely be divided into in vivo and in vitro systems including a number of subdivisions: human/animal, explant/culture, homotypic/heterotypic culture, direct/indirect co-culture, and 3D/monolayer culture. As skin physiology, immunology and wound healing is markedly different in animals and since keloids are exclusive to humans, there is a need for relevant human in vitro models. Of these, the direct co-culture systems that generate full thickness keloid equivalents appear the most promising and will be key to further advance keloid research on its pathogenesis and thereby ultimately advance keloid treatment. Finally, the recent change in keloid nomenclature will be discussed, which has moved away from identifying keloids solely as abnormal scars with a purely cosmetic association toward understanding keloids for the fibroproliferative disorder that they are.

Hyperbaric oxygen therapy improves the effect of keloid surgery and radiotherapy by reducing the recurrence rate

OBJECTIVE

Keloids are exuberant cutaneous scars that form due to abnormal growth of fibrous tissue following an injury. The primary aim of this study was to assess the efficacy and mechanism of hyperbaric oxygen therapy (HBOT) to reduce the keloid recurrence rate after surgical excision and radiotherapy.

METHODS

(1) A total of 240 patients were randomly divided into two groups. Patients in the HBOT group (O group) received HBOT after surgical excision and radiotherapy. Patients in the other group were treated with only surgical excision and radiotherapy (K group). (2) Scar tissue from recurrent patients was collected after a second operation. Hematoxylin and eosin (H&E) staining was used to observe keloid morphology. Certain inflammatory factors (interleukin-6 (IL-6), hypoxia-inducible factor-1α (HIF-1α), tumor necrosis factor-α (TNF-α), nuclear factor κB (NF-κB), and vascular endothelial growth factor (VEGF)) were measured using immunohistochemical staining.

RESULTS

(1) The recurrence rate of the O group (5.97%) was significantly lower than that of the K group (14.15%), P<0.05. Moreover, patients in the O group reported greater satisfaction than those in the K group (P<0.05). (2) Compared with the recurrent scar tissue of the K group, the expression levels of the inflammatory factors were lower in the recurrent scar tissue of the O group.

CONCLUSIONS

Adjunctive HBOT effectively reduces the keloid recurrence rate after surgical excision and radiotherapy by improving the oxygen level of the tissue and alleviating the inflammatory process.

Supportive Use of Adipose-Derived Stem Cells in Cell-Assisted Lipotransfer for Localized Scleroderma

BACKGROUND

The authors aimed to analyze factors related to lipotransfer for localized scleroderma, and to explore the feasibility of cell-assisted lipotransfer for localized scleroderma treatment.

METHODS

Abdominal fat samples were taken from six scleroderma patients without corticosteroid therapy, five scleroderma patients with corticosteroid therapy, and 10 normal liposuction patients. Their quantity, morphology, and proliferation ability were measured. Blood flow was measured by laser speckle contrast imaging in localized scleroderma lesions and normal contralateral regions for eight localized scleroderma patients. Bleomycin-induced skin fibrosis nude mice were also used to investigate differences between lipotransfer and cell-assisted lipotransfer. Fat weight was measured, and expression of transforming growth factor (TGF)-β1 and type III collagen in the injected skin was determined by immunohistochemistry.

RESULTS

The number of stem cells from scleroderma patients with corticosteroid treatment was significantly reduced. Mean blood perfusion in localized scleroderma lesions was not significantly different than in the contralateral normal regions. In normal nude mice, there were no significant changes in TGF-β1 and type III collagen between the control, lipotransfer, and cell-assisted lipotransfer groups, whereas in bleomycin-induced skin fibrosis nude mice, lipotransfer and cell-assisted lipotransfer reduced TGF-β1 and type III collagen expression.

CONCLUSIONS

For scleroderma patients, fewer adipose-derived stem cells, because of a history of corticosteroid therapy and a local inflammatory microenvironment, are more important factors, whereas blood supply showed no significant change. Therefore, cell-assisted lipotransfer not only improves the survival rate of transplanted fat but also improves skin texture in bleomycin-induced skin fibrosis nude mice.

Reconstructed human keloid models show heterogeneity within keloid scars

Keloid scars are often described as having an actively growing peripheral margin with a regressing centre. The aim of this study was to examine the possible heterogeneity within keloids and the involvement of different regions within and around keloid scars in the pathogenesis, using an in vitro keloid scar model. In vitro skin models were constructed from keratinocytes and fibroblasts from normal skin and different regions within and around keloid scars: periphery, centre, and (adjacent) surrounding-normal-skin regions. Additionally, fibroblasts were isolated from the superficial-central and deep-central regions of the keloid and combined with central keratinocytes. All keloid regions showed increased contraction compared to normal skin models, particularly in central regions. Myofibroblasts were present in all keloid regions but were more abundant in models containing central-deep keloid fibroblasts. Secretion of anti-fibrotic HGF and extracellular matrix collagen IV gene expression was reduced in the central deep keloid compared to normal skin. No significant differences between peripheral and central regions within keloids were observed for inflammatory cytokine CCL20, CCL27, CXCL8, IL-6 and IL-18 secretion. Parameters for surrounding-normal-skin showed similarities to both non-lesional normal skin and keloids. In conclusion, a simple but elegant method of culturing keloid-derived keratinocytes and fibroblasts in an organotypic 3D scar model was developed, for the dual purpose of studying the underlying pathology and ultimately testing new therapeutics. In this study, these tissue engineered scar models show that the central keloid region shows a more aggressive keloid scar phenotype than the periphery and that the surrounding-normal-skin also shares certain abnormalities characteristic for keloids.

Clinical and morphological characteristics of the vascular bed of hypertrophic scar tissue in different periods of its formation

Background. The state of the microcirculatory bed in the scar tissue is extremely important for determining the most appropriate methods of conservative and surgical treatments. Only few studies have assessed the vascular features of scar tissue. The objective was to study and analyze the morphological features of the vascular bed of scar tissue and their clinical implications. Materials and methods. Fifty-four patients with hypertrophic post-burn scars were examined. The study used a clinical method and performed histological analysis of the scars biopsy specimens, including a survey light microscopy, a morphometric assessment of the vascular bed as well as the verification of the collagen fibers of scar tissue with an immunohistochemical (IHC) analysis with specific monoclonal antibodies (AT) (Novocastra, Bond) to Type I and III collagens. Results. A significant increase in the total area of the vessels of the rumen in the first 6 months of its formation was observed in comparison with intact skin and later maturation of the scar tissue (in % in 1 mm2 of intact skin – 8.50, in the rumen in terms of up to 6 months – 13.10). The average number of vessels in the scar tissue and the total area of their lumen in the maturing rumen from 2 to 5 years decreased in comparison with that in the intact skin. The nodes were detected in the scars by an early appearance of the clinical signs of vascular disorders including blisters and erosions on thickened and hyperemic scar tissues. Discussion. In the developing hypertrophic rumen, the circulatory conditions gradually deteriorated due to the compression and obliteration of the vessels of the skin with collagen. The enhancement in perfusion recorded using laser Doppler fluorometry may be associated with a significant dilatation of the rumen vessels, rather than because of actual enhanced perfusion. Conclusions. 1. The increase in the vascular cross sectional area in the early stages of scar formation is attributable to the expansion of their lumen vessels. In the ripened rumen, the number of vessels is 3 times less than that in intact skin. 2. Hyperemia of the hypertrophic scar is caused by a substantial widening of the vessels of the scar tissue, and not by an increase in their number. 3. The use of a hypertrophic scar for the creation of rotational and other flaps is associated with a high risk of trophic complications.

Imaging functional blood vessels by the laser speckle imaging (LSI) technique using Q-statistics of the generalized differences algorithm

In this work, we report about q statistics concept to improve the performance of generalized differences algorithm based on intensity histogram for imaging functional blood vessel structures in a rodent window chamber of a mice. The method uses the dynamic speckle signals obtained by transilluminating the rodent window chamber to create activity maps of vasculatures. The proposed method of generalized differences with q statistics (GDq) is very sensitive to the values of defined parameters such as: camera exposure time, the q value and the camera frame number. Appropriate choice of q values enhances the visibility (contrast) of functional blood vessels but at the same time without sacrificing the spatial resolution, which is of utmost importance for in-vivo vascular imaging.