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

Postoperative Time and Anatomic Location Influence Skin Graft Reperfusion Assessed With Laser Speckle Contrast Imaging

OBJECTIVES

Under optimal conditions, afferent and efferent human skin graft microcirculation can be restored 8-12 days postgrafting. Still, the evidence about the reperfusion dynamics beyond this period in a dermato-oncologic setting is scant. We aimed to characterise the reperfusion of human skin grafts over 4 weeks according to the necrosis extension (less than 20%, or 20%-50%) and anatomic location using laser speckle contrast imaging (LSCI).

METHODS

Over 16 months, all eligible adults undergoing skin grafts following skin cancer removal on the scalp, face and lower limb were enroled. Perfusion was assessed with LSCI on the wound margin (control skin) on day 0 and on the graft surface on days 7, 14, 21 and 28. Graft necrosis extension was determined on day 28.

RESULTS

Forty-seven grafts of 47 participants were analysed. Regardless of necrosis extension, graft perfusion equalled the control skin by day 7, surpassed it by day 21, and stabilised onwards. Grafts with less than 20% necrosis on the scalp and lower limb shared this reperfusion pattern and had a consistently better-perfused centre than the periphery for the first 21 days. On the face, the graft perfusion did not differ from the control skin from day 7 onwards, and there were no differences in reperfusion within the graft during the study.

CONCLUSION

Skin graft reperfusion is a protracted process that evolves differently in the graft centre and periphery, influenced by postoperative time and anatomic location. A better knowledge of this process can potentially enhance the development of strategies to induce vessel ingrowth into tissue-engineered skin substitutes.

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).

Revealing the pathogenesis of keloids based on the status: Active vs inactive

Recently, the pathomechanisms of keloids have been extensively researched using transcriptomic analysis, but most studies did not consider the activity of keloids. We aimed to profile the transcriptomics of keloids according to their clinical activity and location within the keloid lesion, compared with normal and mature scars. Tissue samples were collected (keloid based on its activity (active and inactive), mature scar from keloid patients and normal scar (NS) from non-keloid patients). To reduce possible bias, all keloids assessed in this study had no treatment history and their location was limited to the upper chest or back. Multiomics assessment was performed by using single-cell RNA sequencing and multiplex immunofluorescence. Increased mesenchymal fibroblasts (FBs) was the main feature in keloid patients. Noticeably, the proportion of pro-inflammatory FBs was significantly increased in active keloids compared to inactive ones. To explore the nature of proinflammatory FBs, trajectory analysis was conducted and CCN family associated with mechanical stretch exhibited higher expression in active keloids. For vascular endothelial cells (VECs), the proportion of tip and immature cells increased in keloids compared to NS, especially at the periphery of active keloids. Also, keloid VECs highly expressed genes with characteristics of mesenchymal activation compared to NS, especially those from the active keloid center. Multiomics analysis demonstrated the distinct expression profile of active keloids. Clinically, these findings may provide the future appropriate directions for development of treatment modalities of keloids. Prevention of keloids could be possible by the suppression of mesenchymal activation between FBs and VECs and modulation of proinflammatory FBs may be the key to the control of active keloids.

Revisiting roles of mast cells and neural cells in keloid: exploring their connection to disease activity

Background

Mast cells (MCs) and neural cells (NCs) are important in a keloid microenvironment. They might contribute to fibrosis and pain sensation within the keloid. However, their involvement in pathological excessive scarring has not been adequately explored.

Objectives

To elucidate roles of MCs and NCs in keloid pathogenesis and their correlation with disease activity.

Methods

Keloid samples from chest and back regions were analyzed. Single-cell RNA sequencing (scRNA-seq) was conducted for six active keloids (AK) samples, four inactive keloids (IK) samples, and three mature scar (MS) samples from patients with keloids.

Results

The scRNA-seq analysis demonstrated notable enrichment of MCs, lymphocytes, and macrophages in AKs, which exhibited continuous growth at the excision site when compared to IK and MS samples (P = 0.042). Expression levels of marker genes associated with activated and degranulated MCs, including FCER1G, BTK, and GATA2, were specifically elevated in keloid lesions. Notably, MCs within AK lesions exhibited elevated expression of genes such as NTRK1, S1PR1, and S1PR2 associated with neuropeptide receptors. Neural progenitor cell and non-myelinating Schwann cell (nmSC) genes were highly expressed in keloids, whereas myelinating Schwann cell (mSC) genes were specific to MS samples.

Conclusions

scRNA-seq analyses of AK, IK, and MS samples unveiled substantial microenvironmental heterogeneity. Such heterogeneity might be linked to disease activity. These findings suggest the potential contribution of MCs and NCs to keloid pathogenesis. Histopathological and molecular features observed in AK and IK samples provide valuable insights into the mechanisms underlying pain and pruritus in keloid lesions.

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.

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.

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.

Segmental branches emanating from saphenous nerve morphing into sympathetic trunks for innervation of saphenous artery and its clinical implication for arterial sympathectomy

Sympathectomy of arteries has been adopted for the treatment of peripheral arterial disease and Raynaud's disease. However, the exact route for sympathetic axons to reach peripheral arteries awaits further investigation that could pave the way for development of new surgical strategies. In this study, saphenous neurovascular bundles from 10 neonatal Sprague-Dawley rats first were harvested for whole-mount immunostaining to show sympathetic innervation pattern of the artery. Secondly, 40 Sprague-Dawley male rats weighing 350 to 400 g were assigned to five groups, receiving either sham, perivascular sympathectomy, nerve-artery separation, nerve transection in the saphenous neurovascular bundle, or lumbar sympathectomy surgery that removes the lumbar sympathetic trunks. Immediately after surgery, the arterial perfusion and diameter were measured using laser speckling contrast imaging, and 1 week later the saphenous neurovascular bundles were harvested for immunostaining using antibodies against TH, neuron-specific β-tubulin (Tuj 1), and α-SMA to show the presence or absence of the TH-immuopositive staining in the adventitia. The differences among the five groups were determined using one-way analysis of variance (ANOVA). We found that an average of 2.8 ± 0.8 branches with a diameter of 4.8 ± 1.2 μm derived from the saphenous nerve that morphed into a primary and a secondary sympathetic trunk for innervation of the saphenous artery. Nerve-artery separation, nerve transection, and lumbar sympathectomy could eradicate TH-immunopositive staining of the artery, resulting, respectively, in a 12%, 36%, and 59% increase in diameter (P < .05), and a 52%, 63%, and 201% increase in perfusion compared with sham surgery (P < .01). In contrast, perivascular sympathectomy did not have a significant impact on the TH-immunopositive staining, the diameter, and perfusion of the distal part of the artery (P > .05). We conclude that the sympathetic innervation of an artery derives from segmental branches given off from its accompanying nerve. Nerve-artery disconnection is a theoretic option in sympathectomy of an artery.

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.

Mechanically Induced Vasospasm-Evaluation of Spasmolytic Efficacy of 10 Pharmaceutical Agents Using Laser Speckle Contrast Imaging

BACKGROUND AND OBJECTIVES

Vasospasm is a thorny problem often encountered in microvascular surgery that seriously threatens the survival of vascularized tissue transfers. This investigation is dedicated to establishing a model of vasospasm and to evaluating the antispasmodic efficacy of 10 pharmacologic agents.

STUDY DESIGN/MATERIALS AND METHODS

Eighty Sprague-Dawley rats were used. After anesthesia and depilation, the femoral neurovascular bundle was exposed, and a pair of microsurgical forceps were used to trigger vasospasm of the femoral vessels by blunt dissection. Then, 10 pharmacological agents, namely, prostaglandin E1, sodium nitroprusside, magnesium sulfate, papaverine, normal saline, phentolamine, verapamil, 2% lidocaine hydrochloride, amrinone, and 12% lidocaine hydrochloride, were dripped to the femoral vessels, after which laser speckle contrast imaging was used to collect perfusion images, acquiring the perfusion and the inner caliber of the femoral vessels at multiple timepoints. Furthermore, blood perfusion and the time consumed to escape vasospasm and reach hyperperfusion in each group were calculated. The difference of spasmolytic efficacy among the agents was statistically analyzed by one-way analysis of variance.

RESULTS

There was a significant difference in antispasmodic ability among the 10 agents (P < 0.001). 10% magnesium sulfate and 12% lidocaine were distinguished among the 10 agents in resolving the vasospasm. 10% magnesium sulfate demonstrated the best antispasmodic potency, which enabled the shortest time consumed for vessels to escape spasm and reach hyperperfusion. 12% lidocaine ranked second in efficacy, demonstrating a similar effect except that it could not propel the femoral vein to a state of hyperperfusion. For the remaining agents, the time consumed for the artery to escape spasm was all significantly shortened when compared with normal saline (P < 0.001). For the venous spasm, all agents except prostaglandin E1 could significantly shorten the time consumed for the vein to escape spasm (P < 0.001).

CONCLUSIONS

In terms of resolving mechanically induced vasospasm, 10% magnesium sulfate is the best antispasmodic, followed by 12% lidocaine. Lasers Surg. Med. © 2020 Wiley Periodicals LLC.