Keloids and hypertrophic scars: update and future directions

Keloid-associated lymphoid tissues in keloid lesions express vitamin D receptor

Objectives: Vitamin D receptor (VDR) may play a role in keloid disorder. This study investigated the expression of VDR by the embryonic stem cell (ESC)-like population within keloid-associated lymphoid tissues (KALTs) which expresses components of the renin-angiotensin system (RAS). Methods: 11 formalin-fixed paraffin-embedded sections of keloid lesions (KLs) underwent 3,3-diaminobenzidine (DAB) immunohistochemical (IHC) staining for VDR. Immunofluorescence (IF) dual IHC staining of CD34/VDR and OCT4/VDR was performed on two representative KLs. Transcriptional activation of VDR was investigated in four representative snap-frozen KLs using reverse-transcriptase-quantitative polymerase chain reaction (RT-qPCR). Results: DAB IHC staining demonstrated the presence of VDR on the KALTs within the keloid tissue samples. RT-qPCR confirmed transcriptional activation of VDR. IF IHC staining demonstrated expression of VDR on the CD34⁺ and the OCT4⁺ endothelium of the microvessels, and the OCT4⁺ perivascular cells, within the KALTs. Conclusions: This study demonstrated the expression of VDR by the ESC-like population within the KALTs in KLs. Further work is needed to elucidate the precise interaction between VDR and the RAS in regulating the primitive population within the KALTs.

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.

Surgical Excision of Keloids Followed by In-office Superficial Radiation Therapy: Prospective Study Examining Clinical Outcomes

Background:

Keloids are benign proliferative scars that often occur among individuals of color, and are thought to be the result of excessive collagen deposition that occurs after injury to the skin. The treatment of these scars is difficult with often poor outcomes. This study aimed to evaluate the effectiveness of surgical excision followed by in-office superficial radiation therapy (SRT) as a method to improve keloid remission.

Methods:

Participants for this study were recruited from June 2016 through February 2017 with 48 subjects enrolled and completed this study. All keloids were surgically resected and participants received 3 consecutive days of a customized dose of SRT, with a maximum cumulative dosage of 18 Gy. Patients were followed over the course of 12 months to monitor outcomes.

Results:

In this cohort, we found 39 (81%) to have achieved successful remission with 9 (19%) being classified as refractory. There were no adverse effects or medical complications reported as a part of this study.

Conclusion:

Study outcomes support the clinical benefits of surgical excision followed by SRT as a practical and efficient treatment for keloids.

Stem Cells in Keloid Lesions: A Review

Keloid disorder (KD) is a fibroproliferative condition caused by dysregulated wound healing following wounding of the skin. The pathogenesis of KD has not been fully elucidated and current treatment is unsatisfactory. There is increasing evidence of the role of stem cells in KD. This review discusses the role of embryonic stem (ESC)-like cells and mesenchymal stem cells in the pathogenesis of KD. It is proposed that dysfunction of the ESC-like population localized to the endothelium of the microvessels and perivascular cells within the keloid-associated lymphoid tissues may give rise to the aberrant fibroblasts and myofibroblasts via a mesenchymal stem cell intermediate in keloid lesions, by undergoing an endothelial-to-mesenchymal transition. We also discuss the role of the renin-angiotensin system (RAS), the immune system, and the inflammatory response, on stem cell proliferation and differentiation. The understanding of the precise roles of these stem cells and interplay of the associated regulatory pathways could lead to the development of targeted therapy for this enigmatic and challenging condition. The demonstration of the expression of components of the RAS and cathepsins B, D, and G that constitute bypass loops of the RAS, by the ESC-like population, suggests that the primitive population may be a therapeutic target by modulation of the RAS, using existing medications.

miR-188-5p regulates proliferation and invasion via PI3K/Akt/MMP-2/9 signaling in keloids

Keloids (KDs) and hypertrophic scars (HSs), two forms of pathological scars, seriously affect the physical and psychological health of patients. Despite many similarities with HSs, KDs are characterized by invasion and a high rate of recurrence after surgery, features they share in common with tumors. The underlying molecular mechanisms of this phenomenon have not been fully elucidated. In this study, we used microRNA (miRNA) array analysis to search for invasion-associated miRNAs in KDs. The expression of miR-188-5p in KDs, HSs, normal skin (NS) tissues, and cell lines was measured by quantitative real-time polymerase chain reaction. Furthermore, cell proliferation, migration, and invasion were detected in KD fibroblasts (KFs) and HS fibroblasts (HSFs), and interrelated proteins were ascertained by western blot analysis. It was found that miR-188-5p was significantly decreased in KD tissue compared with HS and NS tissues. Upregulated expression of miR-188-5p suppressed KF proliferation, migration, and invasion; and decreased expression of miR-188-5p also promoted HSF proliferation, migration, and invasion. The protein levels of MMP-2, MMP-9, PI3K, and p-Akt in miR-188-5p mimic-transfected KFs were repressed. In contrast, after transfection with miR-188-5p inhibitor, the protein levels of MMP-2, MMP-9, PI3K, and p-Akt were higher than the control in HSFs. Treatment with PI3K/Akt inhibitor LY294002 in KFs with miR-188-5p inhibitor did not further reduce their proliferation, migration, and invasion. The upregulation of MMP-2 and MMP-9 by miR-188-5p inhibitor could be abolished by LY294002. These findings together demonstrate a tumor-suppressive role of miR-188-5p in KD proliferation and invasion via PI3K/Akt/MMP-2/9 signaling, indicating that miR-188-5p may be a potential prognostic marker and therapeutic target for KDs.

Comparison of Fractional CO2 Laser, Verapamil, and Triamcinolone for the Treatment of Keloid

Objective: Scar biology is a territory less understood. The search for ideal treatment of keloid continues. The aim of this study was to compare the role of CO₂ laser, triamcinolone (TAC), and verapamil in the treatment of keloid. Approach: A randomized parallel-group study was conducted in which 60 patients were randomly allocated to three groups from May 2017 to April 2018. First group received fractional CO₂ laser therapy, second group received triamcinolone, and third group received intralesional verapamil. Outcomes were evaluated using Vancouver scar scale score at 3 weekly intervals for 6 months. Results: There was a reduction in scar height, vascularity, and pliability in all the three groups. However, pigmentation was not completely resolved by any of the three modalities. The response was fastest in case of triamcinolone followed by verapamil and laser, which was statistically significant. There was reduction in pain and pruritus in all the three groups and lesser injection site pain with verapamil. There was some amount of charring with CO₂ laser. Innovation: Our study provides evidence that TAC has the fastest response in treating keloids when compared to other modalities. Scar pigmentation is the parameter that is not completely resolved by TAC, verapamil, or CO₂ laser. Conclusion: The study revealed that fractional CO₂ laser and verapamil are as efficient as triamcinolone acetonide (TAC) for treating keloids, except it takes longer for laser and verapamil to act compared to TAC. Verapamil can be used as an alternative treatment modality that is cost-effective with minimal adverse effects.

Chinese expert consensus on clinical prevention and treatment of scar. BURNS & TRAUMA 2018;6:27. [PMID: 30263894 PMCID: PMC6154406 DOI: 10.1186/s41038-018-0129-9]

Following injury, Asian skin has a tendency toward hyperpigmentation and scar formation than Caucasians. A standardized algorithm tailored to Asian patients, especially Chinese patients, is in great demand. Twelve independent, self-selected academic and military physicians from the department of burn/trauma, plastic surgery and dermatology with extensive experience in treating scars were assembled on January 17, 2015, establishing the consensus panel. This consensus was then appraised, drafted, reviewed, and finalized during the following 3 years, aiming to standardize and improve scar prevention and treatment in China. Hopefully, it may also provide some advices and references for the management of scarring in Asian patients.

Effects and safety of triamcinolone acetonide-controlled common therapy in keloid treatment: a Bayesian network meta-analysis

Background

Triamcinolone acetonide (TAC) is used frequently in the treatment of keloid scars, but has presented controversial results. In this study, we aim to evaluate the effectiveness of TAC compared with other common therapies used in keloid treatment.

Methods

MEDLINE, Embase, Web of Science and the Cochrane Library databases were searched until January 2018. Key data were extracted from eligible randomized controlled trials. Both pairwise and network meta-analyses were conducted for synthesizing data from eligible studies.

Results

Ten randomized controlled trials were included in this meta-analysis. The relative risk of keloids associated with seven adjuvants was analyzed, including placebo, pulsed dye laser (PDL), 5-fluorouracil (5-FU), silicone, verapamil, TAC+5-FU and TAC+5-FU+PDL. Patients treated with the following adjuvants appeared to not have significantly reduced risk of keloid in relation to those treated with TAC: placebo (OR=1.86, 95% CI 1.12–2.61), PDL (OR=1.32, 95% CI 0.53–3.30), 5-FU (OR=1.13, 95% CI 0.48–2.68), silicone (OR=1.28, 95% CI 0.59–2.78), verapamil (OR=1.86, 95% CI 0.67–5.14), TAC+5-FU (OR=0.77, 95% CI 0.38–1.58) and TAC+5-FU+PDL (OR=0.80, 95% CI 0.16–4.03). The surface under the cumulative ranking curve values for each adjuvant were as follows: TAC, 59.9%; placebo, 17.4%; PDL, 46.3%; 5-FU, 48.9%; silicone, 56.2%; verapamil, 84.7%; TAC+5-FU, 68.5% and TAC+5-FU+PDL, 18.1%.

Conclusion

There were no differences between the efficacy of TAC and other common therapies in keloid treatment. TAC also acts as an effective alternative modality in the prevention and treatment of keloids. Incorporating adjuvants particularly verapamil appeared to be significantly associated with a decreased risk of keloids.

Identification of mRNA of the Inflammation-associated Proteins CXCL8, CXCR2, CXCL10, CXCR3, and β-Arrestin-2 in Equine Wounded Cutaneous Tissue: a Preliminary Study

Horses often sustain cutaneous wounds and healing can be prolonged and difficult to treat. Compared to body wounds, limb wounds heal slower and are more likely to develop exuberant granulation tissue. Differences in healing rates and exuberant granulation tissue formation is attributed to abnormal cytokine profiles. CXCL8 and its receptor CXCR2 are involved in acute inflammation whereas CXCL10 and its receptor CXCR3 are involved in inflammation resolution. β- arrestin-2 regulates inflammation through internalization of G-protein coupled receptors (GPCRs) including CXCR2 and CXCR3. Gene expression of these five inflammation associated proteins have not been previously identified in equine cutaneous tissue and may play a role in dysregulation of inflammation in equine limb wounds. The mRNA expression levels were measured using QuantiGene Plex Assay from cutaneous biopsies collected from surgically created wounds on the limb and thorax on days 0, 1, 2, 7, 14, and 33 from two horses. The mRNA expression levels were measured in mean fluorescent intensity and graphed. We were successful in identifying all five proteins for the first time in equine cutaneous tissue. Preliminary results suggest that there are different expression patterns for CXCL8, CXCR2 and β-arrestin-2 between the limb and thorax but not for CXCL10 and CXCR3. Differential regulation of CXCL8, CXCR2 and β-arrestin-2 may further explain why limb wounds heal differently than body wounds and warrants further investigation.

Long non-coding RNA CACNA1G-AS1 promotes calcium channel protein expression and positively affects human keloid fibroblast migration

Keloids are a type of benign hyperplasia that cause dermatologic dysfunction and esthetic deformity by invading adjacent normal tissues. Little is known about their etiology, therefore, they are a challenge to treat using plastic surgery. In a previous study, it was demonstrated that the expression of the long non-coding RNA CACNA1G-AS1 (CAS1) is high in keloid tissue, suggesting that CAS1 is involved in keloid formation. In the present study, the aim was to identify potential keloid target proteins by exploring CAS1 biological function during cell proliferation and migration, cytokine secretion, collagen secretion and the control of calcium channel protein expression in human keloid fibroblasts. Three biopsy samples were collected from each patient with keloids at The Peking Union Medical College Hospital, which were then used to investigate the role of CAS1 in cell proliferation and migration. CAS1 silencing was also carried out using small interfering RNA; cell factors, collagen and calcium channel protein levels were compared with control cells. The interference of CAS1 expression reached 50% compared with the control group. CACNA1G and type I collagen expression was significantly downregulated by CAS1 knockdown, while the expression of transforming growth factor-β and type III collagen was not affected. Wound healing time was longer in the CAS1-knockdown group, but there was no visible change in cell proliferation. In conclusion, CAS1 appeared to promote calcium channel protein and type I collagen expression, and to have a positive effect on cell migration in human keloid fibroblasts. Therefore it has potential as a novel therapeutic target for keloids.

Computational analysis identifies putative prognostic biomarkers of pathological scarring in skin wounds

Background

Pathological scarring in wounds is a prevalent clinical outcome with limited prognostic options. The objective of this study was to investigate whether cellular signaling proteins could be used as prognostic biomarkers of pathological scarring in traumatic skin wounds.

Methods

We used our previously developed and validated computational model of injury-initiated wound healing to simulate the time courses for platelets, 6 cell types, and 21 proteins involved in the inflammatory and proliferative phases of wound healing. Next, we analysed thousands of simulated wound-healing scenarios to identify those that resulted in pathological (i.e., excessive) scarring. Then, we identified candidate proteins that were elevated (or decreased) at the early stages of wound healing in those simulations and could therefore serve as predictive biomarkers of pathological scarring outcomes. Finally, we performed logistic regression analysis and calculated the area under the receiver operating characteristic curve to quantitatively assess the predictive accuracy of the model-identified putative biomarkers.

Results

We identified three proteins (interleukin-10, tissue inhibitor of matrix metalloproteinase-1, and fibronectin) whose levels were elevated in pathological scars as early as 2 weeks post-wounding and could predict a pathological scarring outcome occurring 40 days after wounding with 80% accuracy.

Conclusion

Our method for predicting putative prognostic wound-outcome biomarkers may serve as an effective means to guide the identification of proteins predictive of pathological scarring.

Electronic supplementary material

The online version of this article (10.1186/s12967-018-1406-x) contains supplementary material, which is available to authorized users.

Pediatric keloids: A 6-year retrospective review

BACKGROUND/OBJECTIVES

Keloids are reportedly rare at the extremes of life. We sought to describe the epidemiology of pediatric keloids seen at the plastic surgery outpatient department of the University College Hospital, Ibadan.

METHODS

We retrospectively reviewed all children younger than 19 years who presented with nonburn keloids between 2008 and 2014. Data were obtained on age; duration, size, and location of the keloid; family history; mode of treatment; and outcome. Outcome variables were recurrence and wound complications. Data were analyzed using the Pearson chi-square test for discreet variables and the independent-sample t test for continuous variables. P < .05 was taken as statistically significant.

RESULTS

Within the review period, 304 patients presented with keloids, of whom 40 (13.1%) were younger than 19 years. There was a female preponderance (n = 23, 57.5%). The mean age at onset of the keloid was 9.3 years (range 3 months-18 years). Thirty (75%) patients had keloids in the head and neck region. Keloids were sporadic in 31 (77.5%) patients. Nineteen (47.5%) patients had multimodal treatment for keloid. The recurrence rate was 20%. Recurrence was significantly associated with the size of the lesion (P = .003).

CONCLUSION

Keloids during childhood are not rare. More attention should be paid to the management of keloids in this age group.

Dermatologic Microsutures Using Human Hair: A Useful Technique in Cutaneous Stitching

Background: Facial wounds are challenging for dermatologic surgeons, particularly traumatic facial wounds, because they can yield disfiguring scars. To obtain good results, narrow needles and sutures are needed. Hair filaments have a very small diameter (0.06-0.1 mm) and could serve as suture threads for facial wounds. Objective: To determine the aesthetic outcomes by using autologous hair to suture facial wounds. Patients and Methods: This case series study examined the aesthetic outcomes of all consecutive female patients with traumatic facial wounds who underwent autologous hair-based stitching in 2009-2016. Autologous hair ampoules were generated from an insulin needle. Micro instruments were used for wound stitching. Results: In total, 54 females (mean age, 10.8; range, 3-45) years had 56 traumatic wounds. Mean wound length was 3.6 (range, 1-12) cm. Injury depth varied from cutaneous-only to muscle involvement. Suturing yielded good edge coaptation, nice healing, and excellent aesthetic outcomes; the scars were often scarcely visible. Suture marks were not detected. Cutaneous reactions did not occur. Conclusion: Autologous hair can serve as a thread for closing facial wounds. It is low cost and thus suitable in settings characterized by facility and equipment limitations. It is also suitable for the battlefield.

Epidermal Growth Factor (EGF)-Like Repeats and Discoidin I-Like Domains 3 (EDIL3): A Potential New Therapeutic Tool for the Treatment of Keloid Scars

In keloids, the mechanism underlying the excessive accumulation of extracellular matrix after injury of the skin is unclear, and there is no effective treatment because of the incomplete understanding of their pathogenesis; thus, a high recurrence rate is observed. We studied a new marker of keloids to determine a new treatment strategy. First, the keloid gene expression profile (GSE44270) was analyzed (downloaded from the Gene Expression Omnibus database) and the new keloid marker candidate, epidermal growth factor (EGF)-like repeats and discoidin I-like domains 3 (EDIL3) which were upregulated in keloid samples was identified. Knockdown of EDIL3 is known to suppresses angiogenesis by downregulating relevant inhibitory factors that can limit the supply of survival factors to tumor cells from the circulation via the vascular endothelial cells. In keloids, the mechanism of action of EDIL3 may be similar to that in tumors; the inhibition of apoptosis in tumor cells via a reduction in the apoptosis of blood vessels by upregulating an angiogenic factor. To determine whether EDIL3 is involved in keloid formation, we performed knockdown of EDIL3 in keloid fibroblasts in vitro by transfection with anti-EDIL3 small interfering RNA (via microporation). EDIL3 was upregulated in keloid fibroblasts compared with normal fibroblasts in collagen type I, II and III. Our results indicate the control of EDIL3 expression may be a new promising treatment of keloid disease also the molecular targeting of EDIL3 may improve the quality of treatment and reduce the formation of keloids.

A Case of Keloids Complicated by Castleman's Disease: Interleukin-6 as a Keloid Risk Factor

Keloids are a manifestation of a fibroproliferative scarring disorder of the skin and develop in response to dermal injury in patients with a susceptible background. Local, systemic, and genetic factors contribute to keloid susceptibility. These factors include tension on the edges of the wound, hormonal influences, and ethnicity, respectively. Castleman's disease is a rare lymphoproliferative disorder that is characterized by the unregulated overproduction of interleukin-6, which leads to systemic lymphadenopathy and constitutional inflammatory symptoms. This case report shows that the bilateral auricular keloids of an adult woman were greatly exacerbated by the onset of Castleman's disease. We present our multimodal management algorithm for auricular keloids, which involves core excision and radiation therapy and achieves excellent aesthetic outcomes. The current treatment pathway for auricular keloids and the possible relationship between interleukin-6 and keloid progression will be discussed.

Histological analysis of hyalinised keloidal collagen formation in earlobe keloids over time: collagen hyalinisation starts in the perivascular area

Keloids grow and do not regress. They are characterised histologically by hyalinised keloidal collagen (HKC). HKC amounts vary, and the mechanism by which they form is unclear. To clarify how HKCs form and whether their formation associates with specific clinical features, we studied the histological findings of earlobe keloids and compared them with respective clinical features. A total of 50 earlobe keloids from 43 patients were used for histological analysis of keloid size (mm² ), HKC area (mm² ) and HKC area ratio (%). As a result, keloid durations ranged from 3 months to >13 years. Early-stage keloids exhibited little HKC and a tendency for the HKCs to locate in perivascular regions. In later-stage keloids, the HKCs were extremely interconnected and formed a thick bitten donut-shaped region. HKC area ratios correlated positively with keloid duration (r² = 0·58, P<0·05). HKC area ratios and keloid durations did not correlate with keloid sizes. These patterns of HKC formation and growth may explain why local therapies, which effectively remove fibroblasts and accumulated collagen but not HKCs, are ineffective in older keloids. Keloids should be promptly treated after diagnosis, and older keloids with extensive HKCs may require surgical excision followed by radiotherapy.

Keloids and Hypertrophic Scars Can Now Be Cured Completely: Recent Progress in Our Understanding of the Pathogenesis of Keloids and Hypertrophic Scars and the Most Promising Current Therapeutic Strategy

Keloids and hypertrophic scars are fibroproliferative disorders of the skin that are caused by abnormal healing of injured or irritated skin. It is possible that they are both manifestations of the same fibroproliferative skin disorder and just differ in terms of the intensity and duration of inflammation. These features may in turn be influenced by genetic, systemic, and local risk factors. Genetic factors may include single nucleotide polymorphisms, while systemic factors may include hypertension, pregnancy, hormones, and cytokines. The most important local factor is tension on the scar. Over the past 10 years, our understanding of the pathogenesis of keloids and hypertrophic scars has improved markedly. As a result, these previously intractable scars are now regarded as being treatable. There are many therapeutic options, including surgery, radiation, corticosteroids, 5-fluorouracil, cryotherapy, laser therapy, anti-allergy agents, anti-inflammatory agents, bleaching creams and make-up therapies. However, at present, we believe that the following combination of three therapies most reliably achieves a complete cure: surgery, followed by radiation and the use of steroid tape/plaster.

Steroid tape: A promising adjunct to scar management

Introduction:

Intralesional steroid administration is a popular adjunct to scar management with numerous reports in the literature appraising this modality in hypertrophic and keloid scars. The percutaneous delivery of steroids using adhesive tape is an alternative modality, which was first described in the dermatological literature in the 1960s. It is infrequently used in most countries apart from the Orient, where it represents one of the mainstays of specialist scar management protocols.

Methods:

An English and Japanese literature review was performed and reports were stratified using the Joanna Briggs Institute Levels of Evidence. Data were extracted relating to the maximum dose of steroid that can be delivered safely, the reported therapeutic efficacy, as well as the side effects associated with the percutaneous delivery of steroids.

Discussion:

Steroid tape has the potential to be a safe and patient-friendly adjunct to scar management for carefully selected cases of keloid and hypertrophic scars. The main limitation for its widespread adoption is the lack of data to enable the determination of safe exposure thresholds in adult and paediatric patients.

Conclusion:

Despite the existing encouraging reports regarding the potential to be a useful adjunct in scar management, steroid tape is not widely used apart from a limited number of scar services worldwide. Further research is warranted to delineate the role of this modality in specialist scar management protocols.

Steroid medications are frequently used to relieve symptoms as well as improve the appearance of bulky and unsightly scars. In most cases, this treatment involves injections; nevertheless, there is a more patient-friendly way to deliver this type of medicine to scars, which involves a sticky tape. Steroid tape is very popular in the East but is not commonly used in the rest of the world. We undertook this study to find out what has been written about this method of treatment in the skin disease literature and we focused our search on the treatment of scars in particular. We concluded that at present there some studies to support the safe use of steroid tape to treat carefully selected troublesome scars. Nevertheless, further research is needed to determine the maximum size of scar as well as duration of treatment that the steroid tape can be used for.

Keloid progression: a stiffness gap hypothesis

Keloids are fibroproliferative skin disorders characterised clinically by continuous horizontal progression and post-surgical recurrence and histologically by the accumulation of collagen and fibroblast ingredients. Till now, their aetiology remains clear, which may cover genetic, environmental and metabolic factors. Evidence in the involvement of local mechanics (e.g. predilection site and typical shape) and the progress in mechanobiology have incubated our stiffness gap hypotheses in illustrating the chronic but constant development in keloid. We put forward that the enlarged gap between extracellular matrix (ECM) stiffness and cellular stiffness potentiates keloid progression. Matrix stiffness itself provides organisational guidance cues to regulate the mechanosensitive resident cells (e.g. proliferation, migration and apoptosis). During this dynamic process, the ECM stiffness and cell stiffness are not well balanced, and the continuously enlarged stiffness gap between them potentiates keloid progression. The cushion factors, such as prestress for cell stiffness and topology for ECM stiffness, serve as compensations, the decompensation of which aggravates keloid development. It can well explain the typical shape of keloids, their progression in a horizontal but not vertical direction and the post-surgical recurrence, which were evidenced by our clinical cases. Such a stiffness gap hypothesis might be bridged to mechanotherapeutic approaches for keloid progression.

Examination of Epithelial Mesenchymal Transition in Keloid Tissues and Possibility of Keloid Therapy Target

Background:

Keloid is a fibroproliferative skin disorder that is characterized by collagen accumulation and blood vessel proliferation in the reticular layer of the dermis. It is caused by prolonged inflammation after cutaneous injury. Several studies suggested recently that epithelial mesenchymal transition (EMT) is involved in the development of fibrosis. This study assessed whether EMT also participates in keloid development and/or aggravation.

Methods:

Resected keloid (n = 19) and normal skin (n = 13) samples were subjected to immunohistochemical, immunofluorescent, and Western blot analyses of their expression of epidermal (E-cadherin) and mesenchymal (vimentin) proteins.

Results:

Immunohistochemical analysis showed that the keloid tissues had more vimentin-positive cells in the epidermis than the normal tissues. When normal primary keratinocytes were cultured with proinflammatory cytokines, the cobblestone-shaped cells changed to a spindle shape and many vimentin-positive cells were detected. When immortalized HaCaT keratinocytes were cocultured in split-well plates with normal or keloid-derived fibroblasts, they also underwent EMT, as indicated by their greater vimentin expression on Western blot analysis compared with HaCaT cells that were cultured alone.

Conclusions:

EMT was observed in keloid specimens. EMT was induced by inflammatory cytokines and fibroblasts. EMT may be involved in keloid generation and/or aggravation and may have potential as a keloid treatment target.

Lipid nano-bubble combined with ultrasound for anti-keloids therapy

Keloids were characterized by excessive growth of fibrous tissues, and shared several pathological characteristics with cancer. They did put physical and emotional stress on patients in that keloids could badly change appearance of patients. N-(4-hydroxyphenyl) retinamide (4HPR) showed cytotoxic activity on a wide variety of invasive-growth cells. Our work was aim to prepare N-(4-hydroxyphenyl) retinamide-loaded lipid microbubbles (4HPR-LM) combined with ultrasound for anti-keloid therapy. 4HPR-loaded liposomes (4HPR-L) were first prepared by film evaporation method, and then 4HPR-LM were manufactured by mixing 4HPR-L and perfluoropentane (PFP) with ultrasonic cavitation method. The mean particle size and entrapment efficiency 4HPR-LM were 113 nm and 95%, respectively. The anti-keloids activity of 4HPR-LM was assessed with BALB/c nude mice bearing subcutaneous xenograft keloids model. 4HPR-LM, combined with ultrasound, could significantly induce apoptosis of keloid fibroblasts in vitro and inhibited growth of keloids in vivo. Thus, 4HPR-LM could be considered as a promising agent for anti-keloids therapy.

Comparative effect and safety of verapamil in keloid and hypertrophic scar treatment: a meta-analysis

BACKGROUND

Keloids and hypertrophic scars are the most common types of pathological scarring. Traditionally, keloids have been considered as a result of aberrant wound healing, involving excessive fibroblast participation that is characterized by hyalinized collagen bundles. However, the usefulness of this characterization has been questioned. In recent years, studies have reported the appropriate use of verapamil for keloids and hypertrophic scars.

METHODS

Searches were conducted on the databases Medline, Embase, Cochrane, PubMed, and China National Knowledge Infrastructure from 2006 to July 2016. State12.0 was used for literature review, data extraction, and meta-analysis. Treatment groups were divided into verapamil and nonverapamil group. Nonverapamil group includes steroids and intense pulsed light (IPL) therapy. Total effective rates include cure rate and effective rate. Cure: skin lesions were completely flattened, became soft and symptoms disappeared. Efficacy: skin lesions subsided, patient significantly reduced symptoms. Inefficient definition of skin was progression free or became worse. Random-effects model was used for the meta-analysis.

RESULTS

Six studies that included 331 patients with keloids and hypertrophic scars were analyzed. Analysis of the total effective rate of skin healing was performed. The total effective rates in the two groups were 54.07% (verapamil) and 53.18% (nonverapamil), respectively. The meta-analysis showed that there was no difference between the two groups. We also compared the adverse reactions between the verapamil treatment group and the steroids treatment group in two studies, and the result indicated that the verapamil group showed less adverse reactions.

CONCLUSION

There were no differences between the application of verapamil and nonverapamil group in keloids and hypertrophic scars treatment. Verapamil could act as an effective alternative modality in the prevention and treatment of keloid and hypertrophic scars. A larger number of studies are required to confirm our conclusion.

Reconstruction after Anterior Chest Wall Keloid Resection Using Internal Mammary Artery Perforator Propeller Flaps

It is difficult to completely resect huge anterior chest wall keloids and then close the wound directly. We report here our retrospective analysis of our case series of patients with such keloids who underwent reconstruction with internal mammary artery perforator (IMAP) pedicled propeller flaps and then received postoperative high-dose-rate superficial brachytherapy.

[Specificities in children wound healing]

Children have specific characteristics of wound healing. The aim of this study was to describe the specific clinical characteristics of wounds healing in children and to present the current knowledge on the specific mechanisms with regard to infant age. The tissue insult or injury in fetus can heal without scar, mainly due to reduced granulation tissue associated to diminished or even no inflammatory phase, modified extracellular matrix such as the concentration of hyaluronic acid in amniotic liquid, expression and arrangement of collagen and tenascin. Thickness of children skin is a serious negative factor in case of trauma, whereas poor co-morbidities and efficient growth tissue mechanisms are beneficial to good evolution, even in cases of extensive damage and loss of tissue. The subsequent tissue mechanical forces, wound healing during childhood, spanning from the age of 2 until the end of puberty, is associated with more hypertrophic scars, both in duration and in intensity. Consequently, unnecessary surgery has to be avoided during this period when possible, and children with abnormal or pathologic wound healing should benefit from complementary treatments (hydration, massage, brace, silicone, hydrotherapy…), which represent efficient factors to minimize tissue scarring. After wound healing, the growth body rate can be responsible for specific complications, such as contractures, alopecia, and scar intussusceptions. Its evolutionary character implies the need of an attentive follow-up until adult age. Psychologic repercussions, as a consequence of pathologic scars, must be prevented and investigated by the surgeon.

Keloids and Hypertrophic Scars: A Spectrum of Clinical Challenges

Since their earliest description, keloids and hypertrophic scars have beleaguered patients and clinicians alike. These scars can be aesthetically disfiguring, functionally debilitating, emotionally distressing, and psychologically damaging, culminating in a significant burden for patients. Our current understanding of keloid pathophysiology has grown and continues to advance while molecular biology, genetics, and technology provide ever-deepening insight into the nature of wound healing and the pathologic perturbations thereof. Greater understanding will lead to the development and application of refined therapeutic modalities. This article provides an overview of our current understanding of keloids, highlighting clinical characteristics and diagnostic criteria while providing a comprehensive summary of the many therapeutic modalities available. The proposed mechanism, application, adverse events, and reported efficacy of each modality is evaluated, and current recommendations are summarized.

Hypertension: a systemic key to understanding local keloid severity

This study assessed whether hypertension, a circulating factor, influences local keloid severity. This retrospective cross-sectional study involved 304 consecutive patients (13-78 years old) with keloids who were surgically treated in our hospital between January 2011 and August 2013. Their blood pressure (BP), age and gender, and the size and number of their keloids before surgery were recorded. Ordinal logistic regression analyses showed that BP associated significantly with both keloid size and number (all p < 0.0001). Age also associated with keloid size (p < 0.0001). However, a Goodness-of-fit chi-square test showed that the prevalence of hypertension was not higher among keloid patients than in the general Japanese population. This study provides epidemiological evidence for the possibility that primary hypertension may aggravate keloids. We propose that the skin, along with the heart and liver, is a target organ of hypertension. The observations of this study, which require validation with large-scale prospective interventional trials, suggest that keloid patients should be screened for hypertension and that antihypertensive treatments may be of prophylactic and therapeutic value for skin fibrosis.

The molecular basis of hypertrophic scars

Hypertrophic scars (HTS) are caused by dermal injuries such as trauma and burns to the deep dermis, which are red, raised, itchy and painful. They can cause cosmetic disfigurement or contractures if craniofacial areas or mobile region of the skin are affected. Abnormal wound healing with more extracellular matrix deposition than degradation will result in HTS formation. This review will introduce the physiology of wound healing, dermal HTS formation, treatment and difference with keloids in the skin, and it also review the current advance of molecular basis of HTS including the involvement of cytokines, growth factors, and macrophages via chemokine pathway, to bring insights for future prevention and treatment of HTS.

Botulinum toxin for the prevention and healing of wound scars: A systematic review of the literature

BACKGROUND

Botulinum toxin injections have been investigated for the treatment or prevention of hypertrophic scars in several clinical studies. However, its clinical effectiveness has not yet been established.

OBJECTIVE

To examine all available evidence that support the use of botulinum toxin injections for the treatment or prevention of hypertrophic scars in current clinical practice.

METHODS

A systematic review searching the MEDLINE (1966 to 2014), Scopus (2004 to 2014), Popline (1974 to 2014), ClinicalTrials.gov (2008 to 2014) and Cochrane Central Register of Controlled Trials (CENTRAL) (1999 to 2014) databases together with reference lists from included studies was conducted.

RESULTS

Ten studies (255 patients) were included. Of these, 123 patients were injected with botulinum toxin type A, nine patients were offered botulinum toxin type B and the remaining 123 patients represented the control groups. Significantly improved cosmetic outcomes were observed among certain studies using the visual analogue scale (experimental group: median score 8.25 [range 6 to 10]) versus control group: median score 6.38 [range 2 to 9]; P<0.001) and the Stony Brook Scar Evaluation Scale (experimental group score: 6.7 versus control group score: 4.17; P<0.001) assessments. However, the methodological heterogeneity of the included studies, the lack of control group in the majority of them, the use of subjective scales of measurement and the frequent use of patient self-assessment precluded unbiased results.

CONCLUSIONS

Current evidence does not support the usage of botulinum toxin. Future randomized controlled trials are needed in the field to reach firm conclusions regarding its place in current clinical practice.

microRNA deregulation in keloids: an opportunity for clinical intervention?

Keloids are defined as benign dermal scars invading adjacent healthy tissue, characterized by aberrant fibroblast dynamics and overproduction of extracellular matrix. However, the aetiology and molecular mechanism of keloid production remain poorly understood. Recent discoveries have shed new light on the involvement of a class of non-coding RNAs known as microRNAs (miRNA), in keloid formation. A number of miRNAs have differential expression in keloid tissues and keloid-derived fibroblasts. These miRNAs have been characterized as novel regulators of cellular processes pertinent to wound healing, including extracellular matrix deposition and fibroblast proliferation. Delineating the functional significance of miRNA deregulation may help us better understand pathogenesis of keloids, and promote development of miRNA-directed therapeutics against this condition.

The link between hypertension and pathological scarring: does hypertension cause or promote keloid and hypertrophic scar pathogenesis?

Pathological scars, namely, keloids and hypertrophic scars (HSs), are caused by excessive cutaneous wound healing that is characterized by histological extracellular matrix (ECM) accumulation, clinically relevant irritating symptoms, and frequent recurrence after surgical excision. To date, there are few effective and specific treatments. This partly reflects the poor understanding of the etiology of these scars and the lack of a suitable animal model. Systemic hypertension has been suggested to participate in pathological scarring. The evidence that supports this hypothesis is reviewed here. Thus, hypertension associates with changes that resemble the aberrant cutaneous wound-healing phases that characterize pathological scar development. It also associates with profibrotic functional changes in the cells that constitute keloids and HSs (endothelial cells, pericytes/myofibroblasts, dermal fibroblasts, and mast cells) and profibrotic ECM remodeling. These hypertension-associated changes are mediated to some extent by inflammation, hypoxia, and the angiotensin/renin-angiotensin-aldosterone system. Thus, hypertension may be an aggravating/risk factor for keloids and HSs. This will help to identify patients who are prone to heavy scars after surgery or postsurgical recurrence. Moreover, pharmacological agents for the prophylaxis and treatment of hypertension-induced fibrosis in other organs may also be useful for keloids/HSs.

Recent developments in the use of intralesional injections keloid treatment

Keloid scars are often considered aesthetically unattractive and frustrating problems that occur following injuries. They cause functional and cosmetic deformities, displeasure, itching, pain, and psychological stress and possibly affect joint movement. The combination of these factors ultimately results in a compromised quality of life and diminished functional performance. Various methods have been implemented to improve keloid scars using both surgical and non-surgical approaches. However, it has proven to be a challenge to identify a universal treatment that can deliver optimal results for all types of scars. Through a PubMed search, we explored most of the literature that is available about the intralesional injection treatment of hypertrophic scars and keloids and highlights both current (corticosteroid, 5-fluorouracil, bleomycin, interferon, cryotherapy and verapamil) and future treatments (interleukin-10 and botulinum toxin type A). The reference lists of retrieved articles were also analysed. Information was gathered about the mechanism of each injection treatment, its benefits and associated adverse reactions, and possible strategies to address adverse reactions to provide reliable guidelines for determining the optimal treatment for particular types of keloid scars. This article will benefit practitioners by outlining evidence-based treatment strategies using intralesional injections for patients with hypertrophic scars and keloids.

Pharmacological treatment for keloids

INTRODUCTION

Keloids are fibroproliferative disorders that are characterized by histological accumulation of collagens and fibroblasts, refractory clinical symptoms such as itching, topical invasiveness, and frequent postsurgical recurrence. At present, to treat or prevent keloids, new drugs are currently being designed and the pharmaceutical indications of known drugs are being expanded.

AREAS COVERED

The current pharmacological interventions for keloids are mainly described on the basis of the various hypotheses on keloid etiology and the keloid ingredients that are targeted. These interventions include angiotension-converting enzyme inhibitors and calcium-channel blockers (based on hypertension hypothesis), selective estrogen receptor modulator (based on endocrinological hypothesis), vitamins and essential fatty acids (based on immunonutritional hypothesis), and transglutaminase inhibitor (based on metabolic hypothesis). Drugs that directly target the reduction or destruction of the major extracellular matrix or cellular constituents of keloids are also included. Besides, drugs that indirectly modulate the biochemical microenvironment are described. These include growth factors, immunomodulators, and anti-inflammation and anti-allergy drugs.

EXPERT OPINION

Due to the unclear etiology of keloids and the lack of animal models, efficient, reliable, and specific pharmaceutical interventions for keloids continue to be lacking. The reliability of current data and clinical observations must be strengthened by large-scale, randomized, controlled clinical trials.