Endothelial dysfunction may promote keloid growth

Recurrent Auricular Keloid After Childbirth in a Patient With von Willebrand Disease

The authors present a case of a 34-year-old female patient with von Willebrand disease who developed a recurrent right auricular keloid after childbirth. The patient had previously undergone surgical excision of the keloid in 2017, which led to the diagnosis of von Willebrand disease due to uncontrolled bleeding. After a successful pregnancy in 2023, the patient experienced keloid recurrence. Surgical excision and radiotherapy were performed in April 2023, followed by DDAVP administration to control postoperative bleeding. At 1-year follow-up, no recurrence was observed. This case highlights the potential impact of pregnancy on keloid recurrence and the challenges of managing keloids in patients with bleeding disorders.

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.

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

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

Characterization of the skin keloid microenvironment

Keloids are a fibroproliferative skin disorder that develops in people of all ages. Keloids exhibit some cancer-like behaviors, with similar genetic and epigenetic modifications in the keloid microenvironment. The keloid microenvironment is composed of keratinocytes, fibroblasts, myofibroblasts, vascular endothelial cells, immune cells, stem cells and collagen fibers. Recent advances in the study of keloids have led to novel insights into cellular communication among components of the keloid microenvironment as well as potential therapeutic targets for treating keloids. In this review, we summarized the nature of genetic and epigenetic regulation in keloid-derived fibroblasts, epithelial-to-mesenchymal transition of keratinocytes, immune cell infiltration into keloids, the differentiation of keloid-derived stem cells, endothelial-to-mesenchymal transition of vascular endothelial cells, extracellular matrix synthesis and remodeling, and uncontrolled angiogenesis in keloids with the aim of identifying new targets for therapeutic benefit. Video Abstract.

Over 90% Percent of Childhood BCG Vaccine-Induced Keloids in Japan Occur in Women

INTRODUCTION

Keloids are a fibroproliferative, multifactorial, cutaneous disorder whose pathophysiology is not completely understood. Various factors such as high blood pressure, pregnancy, female gender, mechanical tension of local sites, and prolonged wound healing are known to worsen keloids. Childhood-onset keloids are keloids that form before 10 years of age, before various factors in adulthood come into play, and thus studying childhood-onset keloids may provide additional insight into the underlying mechanisms that lead to keloid formation.

METHODS

Retrospective chart review was performed on all patients with childhood-onset keloids who were evaluated at our plastic surgery clinic (one of the largest keloid referral centers in Japan) over a 1-year period.

RESULTS

Of the 1443 patients with diagnosis of keloids, 131 patients had childhood-onset keloids. Of these, 106 patients (80.9%) were female, 38.9% of patients had family history of keloids, and 48.9% of patients had allergies or allergy-related conditions (asthma, atopic dermatitis, or allergic rhinitis). Vaccination (47.5%) and chickenpox (19.9%) were the most common triggers. Of vaccinations, BCG was the most common trigger. The majority of keloids from BCG were in female patients (92.9%). The most common location was the chest in male patients (30.0%) and the arm in female patients (41.1%).

CONCLUSION

To our knowledge, this is the largest report in the literature on childhood-onset keloids. There was overall female predominance in childhood-onset keloids, and even more significant female predominance in BCG-induced keloids.

Bioinformatics analysis and identification of dysregulated POSTN in the pathogenesis of keloid

Keloid is a benign fibro-proliferative dermal tumour formed by an abnormal scarring response to injury and characterised by excessive collagen accumulation and invasive growth. The pathophysiology of keloids is complex, and the treatment for keloids is still an unmet medical need. Here, we investigated the transcriptional gene that influences keloid development by comparing keloid, non-lesioned keloid skin and normal skin as well as keloid fibroblast and normal fibroblast (GSE83286, GSE92566, GSE44270). Based on the analysis, 146 up-regulated genes and 48 down-regulated genes were found in keloid tissue compared with normal skin and keloid no-lesioned skin. Eleven genes were further identified by overlapping the DEGs from keloid tissue described previously with DEGs in keloid fibroblast. The overlapped genes included PRR16, SFRP2, EDIL3, GERM1, POSTN, PDE3A, GALNT5, F2RL2, EYA4, ZFHX4, and AIM2. POSTN is the most crucial node in PPI network, which mainly correlate to collagen-related genes. Moreover, siRNA knockdown identified POSTN is a crucial regulatory gene that regulates keloid fibroblast migration and collagen I, collagen III expression level. In conclusion, our study identified 11 hub genes that play crucial role in keloid formation and provided insights for POSTN to be the therapeutic target for keloid through bioinformatic analysis of three datasets. Additionally, our results would support the development of future therapeutic strategies.

Bioinformatics study on different gene expression profiles of fibroblasts and vascular endothelial cells in keloids

Keloid is a benign fibroproliferative skin tumor. The respective functions of fibroblasts and vascular endothelial cells in keloid have not been fully studied. The purpose of this study is to identify the respective roles and key genes of fibroblasts and vascular endothelial cells in keloids, which can be used as new targets for diagnosis or treatment.The microarray datasets of keloid fibroblasts and vascular endothelial cells were obtained from the Gene Expression Omnibus (GEO) database. Differentially expressed genes (DEGs) were screened out. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) were used for functional enrichment analysis. The search tool for retrieval of interacting genes and Cytoscape were used to construct protein-protein interaction (PPI) networks and analyze gene modules. The hub genes were screened out, and the relevant interaction networks and biological process analysis were carried out.In fibroblasts, the DEGs were significantly enriched in collagen fibril organization, extracellular matrix organization and ECM-receptor interaction. The PPI network was constructed, and the most significant module was selected, which is mainly enriched in ECM-receptor interaction. In vascular endothelial cells, the DEGs were significantly enriched in cytokine activity, growth factor activity and transforming growth factor-β (TGF-β) signaling pathway. Module analysis was mainly enriched in TGF-β signaling pathway. Hub genes were screened out separately.In summary, the DEGs and hub genes discovered in this study may help us understand the molecular mechanisms of keloid, and provide potential targets for diagnosis and treatment.

Intralesional pentoxifylline, triamcinolone acetonide, and their combination for treatment of keloid scars

BACKGROUND

Keloids are common fibroproliferative tumors, and their treatment still represents a dilemma. Intralesional triamcinolone acetonide (TAC) injection is effective, but frequently associated with side effects. Pentoxifyllin (PTX) is a vasodilator, anti-inflammatory, and antifibrotic agent. Its intralesional injection in keloids has not been evaluated yet.

AIMS

Evaluating the efficacy and safety of intralesional PTX versus intralesional TAC and their combination for treatment of keloids.

PATIENTS/METHODS

Thirty patients with keloids were divided into three equal groups and treated by intralesional injection of TAC, PTX, or their combination (admixed in 1:1 ratio). Injections were repeated every 3 weeks until lesional flattening or for maximum of 5 sessions. The evaluation was done using the Vancouver Scar Scale and the Verbal Rating Scale for pain and itching.

RESULTS

A significant improvement in VSS was detected in all groups. Significantly better improvements in keloid height, pliability, pain, and itching were detected in the TAC and combination groups than in the PTX group. There was a significantly higher incidence of side effects (atrophy, hypopigmentation, telangiectasia, and precipitation of TAC) in the TAC group than in the combination group, while no side effects were reported in the PTX group. A statistically significant reduction in the number of treatment sessions (required to achieve best results) was detected in patients in the combination group.

CONCLUSIONS

Intralesional injection of PTX is a potentially helpful, safe, and well-tolerated therapeutic tool for keloids, but with lower efficacy than intralesional TAC when used solely. Combining PTX and TAC produces significantly better results for keloid treatment and lowers the risk of TAC-induced side effects.

Norcantharidin-blocked ANXA2P2 inhibits fibroblast proliferation by increasing UBAP2L mRNA stability through LIN28B

AIMS

Norcantharidin (NCTD) exhibits antitumor, anti-inflammatory, and anti-fibrosis properties, which makes NCTD an attractive candidate for the treatment of pathological scars. This study was designed to investigate the potential effects of NCTD on fibroblast proliferation and explore the underlying mechanisms.

MATERIALS AND METHODS

First, cell viability and cell apoptosis were evaluated to determine the effects of NCTD on human skin fibroblasts, at 10, 50, and 100 μM. To explore the mechanism, bioinformatics analyses, chromatin immunoprecipitation, RNA immunoprecipitation, and RNA pulldown assays, and luciferase reporter assays were performed to verify the relationships among NCTD, signal transducer and activator of transcription 3 (STAT3), annexin A2 pseudogene 2 (ANXA2P2), and ubiquitin-associated protein 2-like (UBAP2L) mRNA in fibroblasts. Loss-of-function experiments were performed to investigate the roles played by STAT3, ANXA2P2, and UBAP2L in the proliferation and apoptosis of fibroblasts.

KEY FINDINGS

We found that NCTD administration induced fibroblast apoptosis and inhibited fibroblast proliferation in a dose-dependent manner. Mechanistically, NCTD inhibited ANXA2P2 transcription through the inhibition of STAT3 phosphorylation. Subsequently, ANXA2P2 was found to enhance the physical interaction between UBAP2L mRNA and lin-28 homolog B (LIN28B), which increased the stability and levels of UBAP2L mRNA. Loss-of-function assays demonstrated that ANXA2P2 and UBAP2L knockdown induced fibroblast apoptosis and suppressed fibroblast proliferation.

SIGNIFICANCE

In conclusion, we confirmed that NCTD inhibits fibroblast proliferation by inhibiting the STAT3/ANXA2P2/UBAP2L axis, which suggested that NCTD could represent a new candidate for the treatment of pathological scars.

Acne keloidalis nuchae and hypertension in black subjects: a case–control study

Objective

The aim of this case–control study was to look for an association between hypertension and acne keloidalis nuchae (AKN) in black subjects.

Results

We recruited 303 consenting subjects comprising 101 patients with AKN and 202 controls, case-matched by age (± 5 years). The mean patients age was 34.9 ± 10.7 years versus 35.6 ± 11.2 years for controls. The average duration of AKN progression in cases prior to consultation was 1831 days (5 years). The most frequently observed AKN lesions were papules (73/101; 72.3%), fibrous scars (42/101; 41.6%) and folliculitis/pustules (41/101; 40.6%). In terms of quality of life, the mean score of dermatology life quality index was 8.3 ± 5.2 (extremes: 0 to 22). In multivariate analysis, having a BMI of 25 kg/m² or more (OR = 4.91; p < 0.001) and having systolic hypertension (OR = 1.22; p = 0.010) were associated with AKN.

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.

The Vascular Involvement in Soft Tissue Fibrosis-Lessons Learned from Pathological Scarring

Soft tissue fibrosis in important organs such as the heart, liver, lung, and kidney is a serious pathological process that is characterized by excessive connective tissue deposition. It is the result of chronic but progressive accumulation of fibroblasts and their production of extracellular matrix components such as collagens. Research on pathological scars, namely, hypertrophic scars and keloids, may provide important clues about the mechanisms that drive soft tissue fibrosis, in particular the vascular involvement. This is because these dermal fibrotic lesions bear all of the fibrotic characteristics seen in soft tissue fibrosis. Moreover, their location on the skin surface means they are readily observable and directly treatable and therefore more accessible to research. We will focus here on the roles that blood vessel-associated cells play in cutaneous scar pathology and assess from the literature whether these cells also contribute to other soft tissue fibroses. These cells include endothelial cells, which not only exhibit aberrant functions but also differentiate into mesenchymal cells in pathological scars. They also include pericytes, hepatic stellate cells, fibrocytes, and myofibroblasts. This article will review with broad strokes the roles that these cells play in the pathophysiology of different soft tissue fibroses. We hope that this brief but wide-ranging overview of the vascular involvement in fibrosis pathophysiology will aid research into the mechanisms underlying fibrosis and that this will eventually lead to the development of interventions that can prevent, reduce, or even reverse fibrosis formation and/or progression.

Sex Differences in Keloidogenesis: An Analysis of 1659 Keloid Patients in Japan

INTRODUCTION

Keloids are a cutaneous fibroproliferative disorder. Despite the fact that keloids are relatively common lesions, the statistics of patient with keloids especially sex difference remain unknown. To better understand it, we conducted an extensive cross-sectional analysis of a large cohort of patients with keloids (n = 1659). The study showed for the first time that female sex may be an inherent keloid risk factor.

METHODS

This cross-sectional study of 1659 consecutive patients with keloids who attended a plastic surgery outpatient clinic in Japan in 2014 analyzed age at keloid onset, age at the first medical examination for keloid, and the influence of sex on these variables.

RESULTS

In both male and female patients, the keloids were most likely to start in puberty and there was no significant difference in the mode value for age of onset (16 vs. 20 years). Though female patients were twice as prevalent as male patients at nearly all onset ages, female patients predominated over male patients with a gender ratio of 2.7:1 in cases of onset before the age of 15 years. Moreover male and female patients did not differ in terms of the mean ± SD duration between keloid onset and the first medical examination. This finding shows that female patients do not get their keloids examined earlier than male patients. These observations together suggest that female sex may promote early keloid development due to physiological, not social, reasons.

CONCLUSION

This is the first report to suggest that female sex may drive keloidogenesis because of physiological reasons. Individuals were most likely to seek a medical examination almost 10 years after onset, regardless of sex. These findings provide new insight into the importance of sex in the development and progression of keloids. Future studies should address the influence of sex hormones on the keloid.

The Role of the Renin-Angiotensin System and Vitamin D in Keloid Disorder-A Review

Keloid disorder (KD) is a fibroproliferative condition characterized by excessive dermal collagen deposition in response to wounding and/or inflammation of the skin. Despite intensive research, treatment for KD remains empirical and unsatisfactory. Activation of the renin-angiotensin system (RAS) leads to fibrosis in various organs through its direct effect and the resultant hypertension, and activation of the immune system. The observation of an increased incidence of KD in dark-skinned individuals who are predisposed to vitamin D deficiency (VDD) and hypertension, and the association of KD with hypertension and VDD, all of which are associated with an elevated activity of the RAS, provides clues to the pathogenesis of KD. There is increasing evidence implicating embryonic-like stem (ESC) cells that express ESC markers within keloid-associated lymphoid tissues (KALTs) in keloid lesions. These primitive cells express components of the RAS, cathepsins B, D, and G that constitute bypass loops of the RAS, and vitamin D receptor (VDR). This suggests that the RAS directly, and through signaling pathways that converge on the RAS, including VDR-mediated mechanisms and the immune system, may play a critical role in regulating the primitive population within the KALTs. This review discusses the role of the RAS, its relationship with hypertension, vitamin D, VDR, VDD, and the immune system that provide a microenvironmental niche in regulating the ESC-like cells within the KALTs. These ESC-like cells may be a novel therapeutic target for the treatment of this enigmatic and challenging condition, by modulating the RAS using inhibitors of the RAS and its bypass loops and convergent signaling pathways.

Keloid patients have higher peripheral blood endothelial progenitor cell counts and CD34+ cells with normal vasculogenic and angiogenic function that overexpress vascular endothelial growth factor and interleukin-8

BACKGROUND

One suggested reason for aberrant wound healing in keloid scars is chronic inflammation of the dermis. We hypothesized that excessive blood vessel formation and high capillary density in keloid tissue is caused by dysfunction of endothelial progenitor cells.

METHODS

We compared the number of circulating endothelial progenitor cells and vasculogenic and angiogenic capacity, as well as secretory function, of circulating CD34⁺ cells in keloid patients and healthy individuals.

RESULTS

Compared to mononuclear cell cultures from healthy donors, cultures of peripheral blood mononuclear cells obtained from keloid patients showed a more than twofold increase in the number of peripheral blood EPCs (fibronectin-adhering cells that phagocytized acetylated low-density lipoprotein and bound Ulex europaeus agglutinin-I lectin). However, there was no difference in colony-forming ability and participation in in vitro angiogenesis between circulating CD34⁺ cells isolated from keloid patients and healthy individuals. This means that circulating CD34⁺ /endothelial progenitor cells in keloid patients have normal vasculogenic and angiogenic function. However, CD34⁺ cells derived from keloid patients demonstrated a more than sevenfold expression of the interleukin-8 gene and a more than fivefold expression of the vascular endothelial growth factor gene than CD34⁺ cells derived from healthy individuals.

CONCLUSIONS

These results support the role of vascular endothelial growth factor and interleukin-8 in increased recruitment of endothelial progenitor cells in keloid patients.

AMF siRNA treatment of keloid through inhibition signaling pathway of RhoA/ROCK1

A keloid (KD) is a benign dermal fibrotic tumor. Treatment of KDs is challenging and the recurrence rate is high; thus, there is an unmet need to explore new target sites and new treatment methods. As a tumor-associated cytokine, autocrine motility factor (AMF) can effectively stimulate the random and directional movement of cells. We first found that AMF was overexpressed in keloid fibroblasts (KFs) and the proliferation and migration of KFs were promoted by AMF stimulation. After treatment with Y-27632, RhoA kinase inhibitor, the proliferation and migration capacity of KFs declined significantly, and type I collagen protein, active RhoA and ROCK1 also were downregulated. In addition, a KD transplantation model was established under the skin of nude mice, with KD intramural injection AMF siRNA, we found that the weight of the KD was smaller than in the control group (P < 0.05), KD tissue sections stained by HE and Masson showed that fibers became loose and the blood vessels were visibly reduced. In conclusion, AMF siRNA is expected to be a novel strategy to treat KD by inhibiting signaling pathway of RhoA/ROCK1.