Promoted activation of matrix metalloproteinase (MMP)-2 in keloid fibroblasts and increased expression of MMP-2 in collagen bundle regions: implications for mechanisms of keloid progression

Hydrogel Loaded with Components for Therapeutic Applications in Hypertrophic Scars and Keloids

Hypertrophic scars and keloids are common fibroproliferative diseases following injury. Patients with pathologic scars suffer from impaired quality of life and psychological health due to appearance disfiguration, itch, pain, and movement disorders. Recently, the advancement of hydrogels in biomedical fields has brought a variety of novel materials, methods and therapeutic targets for treating hypertrophic scars and keloids, which exhibit broad prospects. This review has summarized current research on hydrogels and loaded components used in preventing and treating hypertrophic scars and keloids. These hydrogels attenuate keloid and hypertrophic scar formation and progression by loading organic chemicals, drugs, or bioactive molecules (such as growth factors, genes, proteins/peptides, and stem cells/exosomes). Among them, smart hydrogels (a very promising method for loading many types of bioactive components) are currently favoured by researchers. In addition, combining hydrogels and current therapy (such as laser or radiation therapy, etc.) could improve the treatment of hypertrophic scars and keloids. Then, the difficulties and limitations of the current research and possible suggestions for improvement are listed. Moreover, we also propose novel strategies for facilitating the construction of target multifunctional hydrogels in the future.

Intralesional Cryosurgery of a Bulky Postburned Auricular Keloid and EAR-Q Patient-reported Outcome Measure Assessment

Postburned auricular keloids are a challenging problem for the patient and physician. We describe a successful combined treatment of a bulky postburn auricular keloid employing intralesional cryosurgery followed by multiple W-plasty. An EAR-Q pre- and postoperative patient-reported outcome assessments have revealed a significant improvement in all ear parameters of appearance, adverse effects, and quality of life. This combined treatment might be added to the armamentarium of possible treatment modalities for this perplexing problem.

Laser Therapy Changes the Expression of Matrix Metalloproteinases in Bleomycin-Induced Skin Fibrosis

Matrix metalloproteinases (MMPs) are often considered biomarkers of skin fibrosis. At the early stages of the pathological process, an elevation of their enzymatic activity causes significant changes in the composition of the extracellular matrix. MMPs secreted by immune cells facilitate their migration to the site of damage. Then, the immune cells eliminate the affected cells and biomolecules. Moreover, bidirectional changes in the activity of proteolytic enzymes, including MMPs, accompany wound healing. This study aimed to assess changes in the expression of Mmp2, Mmp3, and Mmp9 after treating mice with laser therapy using the experimental model of bleomycin-induced skin fibrosis. Using immunohistochemistry, we characterized the histological features of scarred skin. We also analyzed changes in the expression of MMPs using real-time polymerase chain reaction before and after laser irradiation. We showed that treatment of the mice with a CO2 laser partially normalized the histological features of scarred skin. We also noticed a decrease in the expression of Mmp2, Mmp3 (both p < 0.05), and Mmp9 (p = 0.065) during scar healing. The obtained results suggest that normalization of skin homeostasis requires control of MMP activity via induction of genes.

OLDER PATIENTS AND PATIENTS WITH SEVERE ARTERIOSCLEROSIS ARE LESS LIKELY TO DEVELOP KELOIDS AND HYPERTROPHIC SCARS AFTER THORACIC MIDLINE INCISION: A SURVEY-BASED ANALYSIS OF 328 CASES

BACKGROUND

Surgery is a well-known trigger of keloid and hypertrophic scarring. Sternotomy scars are subject to high skin tension, which is also known to promote pathological scarring. This suggests that sternotomies in adults associate with high pathological-scarring rates, which is also our anecdotal experience. However, this notion has never been formally examined. Therefore, we conducted a survey-based cohort study of patients who had undergone a sternotomy.

STUDY DESIGN

All consecutive Japanese adults (≥18 years) who underwent cardiovascular surgery with sternotomy in 2014-2017 were identified in 2019 by chart review and sent a questionnaire. Respondents formed the study cohort. The questionnaire presented randomly-ordered photos of representative mature, keloid, and hypertrophic scars and asked the patients to choose the image that best resembled their midline scar when it was particularly noticeable. The incidence of self-reported pathological scarring (keloids and hypertrophic scars were grouped together) and the patient demographic (age and sex) and clinical characteristics (e.g. intima media thickness of the left and right common and internal carotid arteries) that associated with pathological scarring were determined.

RESULTS

Of the 548 sternotomy patients, 328 (mean age, 67 years; 68.0% male) responded (60% response rate). Of these, 195 (59.5%) reported they had a pathological scar. Compared to mature-scar patients, pathological-scar patients had lower mean age (65 vs. 69 years, p=0.0002) and intima-media thickness (0.92 vs. 1.05 mm, p=0.028).

CONCLUSION

Sternotomy was associated with a high rate of pathological scarring. An older age and arteriosclerosis were associated with less pathological scarring.

Advances in the pathogenesis and clinical application prospects of tumor biomolecules in keloid

Keloid scarring is a kind of pathological healing manifestation after skin injury and possesses various tumor properties, such as the Warburg effect, epithelial-mesenchymal transition (EMT), expression imbalances of apoptosis-related genes and the presence of stem cells. Abnormal expression of tumor signatures is critical to the initiation and operation of these effects. Although previous experimental studies have recognized the potential value of a single or several tumor biomolecules in keloids, a comprehensive evaluation system for multiple tumor signatures in keloid scarring is still lacking. This paper aims to summarize tumor biomolecules in keloids from the perspectives of liquid biopsy, genetics, proteomics and epigenetics and to investigate their mechanisms of action and feasibility from bench to bedside. Liquid biopsy is suitable for the early screening of people with keloids due to its noninvasive and accurate performance. Epigenetic biomarkers do not require changes in the gene sequence and their reversibility and tissue specificity make them ideal therapeutic targets. Nonetheless, given the ethnic specificity and genetic predisposition of keloids, more large-sample multicenter studies are indispensable for determining the prevalence of these signatures and for establishing diagnostic criteria and therapeutic efficacy estimations based on these molecules.

The emerging therapeutic targets for scar management: genetic and epigenetic landscapes

Background

Wound healing is a complex process including hemostasis, inflammation, proliferation, and remodeling during which an orchestrated array of biological and molecular events occurs to promote skin regeneration. Abnormalities in each step of the wound healing process lead to reparative rather than regenerative responses, thereby driving the formation of cutaneous scar. Patients suffering from scars represent serious health problems such as contractures, functional and esthetic concerns as well as painful, thick, and itchy complications, which generally decrease the quality of life and impose high medical costs. Therefore, therapies reducing cutaneous scarring are necessary to improve patients' rehabilitation.

Summary

Current approaches to remove scars, including surgical and nonsurgical methods, are not efficient enough, which is in principle due to our limited knowledge about underlying mechanisms of pathological as well as the physiological wound healing process. Thus, therapeutic interventions focused on basic science including genetic and epigenetic knowledge are recently taken into consideration as promising approaches for scar management since they have the potential to provide targeted therapies and improve the conventional treatments as well as present opportunities for combination therapy. In this review, we highlight the recent advances in skin regenerative medicine through genetic and epigenetic approaches to achieve novel insights for the development of safe, efficient, and reproducible therapies and discuss promising approaches for scar management.

Key Message

Genetic and epigenetic regulatory switches are promising targets for scar management, provided the associated challenges are to be addressed.

Research progress in immune microenvironment regulation of muscle atrophy induced by peripheral nerve injury

Denervated skeletal muscular atrophy is primarily characterized by loss of muscle strength and mass and an unideal functional recovery of the muscle after extended denervation. This review emphasizes the interaction between the immune system and the denervated skeletal muscle. Immune cells such as neutrophils, macrophages and T-cells are activated and migrate to denervated muscle, where they release a high concentration of cytokines and chemokines. The migration of these immune cells, the transformation of different functional immune cell subtypes, and the cytokine network in the immune microenvironment may be involved in the regulatory process of muscle atrophy or repair. However, the exact mechanisms of the interaction between these immune cells and immune molecules in skeletal muscles are unclear. In this paper, the immune microenvironment regulation of muscle atrophy induced by peripheral nerve injury is reviewed.

Effects of combined Pulsed Dye Laser and Fractional CO2 Laser treatment of burn scars and correlation with plasma levels of collagen type I, MMP-2 and TIMP-1

Hypertrophic burn scars remain a significant burden for patients and a challenge for clinicians.

THE AIM

Assessement of the efficacy of combined Pulsed Dye Laser and Ablative Fractional CO₂ Laser therapy on hyperthophic scars and correlation with plasma levels of MMP-2, TIMP-1 and alpha-1 type I collagen.

PATIENTS AND METHODS

Twenty five pediatric subjects were enrolled into the study. Control group consisted of age-matched subjects admitted for surgical repair of inguinal hernia. For the assessment of the results of laser treatment we used the Vancouver scar scale (VSS), and Patient-Observer Scar Assessment Scale (POSAS). We also correlated clinical results with plasma levels of MMP-2, TIMP-1 and alpha-1 type I collagen.

RESULTS

All subjects reported the laser treatment resulted in improvement and were somewhat satisfied or very satisfied with their experience. No adverse events were reported. The levels of MMP-2, TIMP-1 and alpha-1 type I collagen in our patients with scars before laser threatment were higher in comparison to controls. We also found statistically significant decrease in the levels of MMP-2, TIMP-1 and alpha-1 type I collagen after laser treatment of burn scars CONCLUSIONS: Our study clearly shows that combined CO2-AFL treatment for burn scars improve texture, colour, function and alleviate pruritus. We believe that decrease in the levels of MMP-2, TIMP-1 and alpha-1 type I collagen after laser treatment of burn scars, reflects reduced dynamic of scar.

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

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

MMP-2 and TIMP-2 expression, quantitative analysis and biomechanical changes in scar hypertrophy after autologous free transplantation of rabbit oral mucosa and scrotal skin

This study aimed to investigate the long-term scar hypertrophy in the rabbit transplanted oral mucosa and scrotal skin with changed matrix environment, as well as the scar location expression, quantitative analysis of matrix metalloproteinase-2 (MMP-2) and tissue inhibitor of metalloproteinase-2 (TIMP-2) and biomechanical changes in the transplanted tissues. The split-thickness skin grafts were collected from the oral mucosas and scrotal skins of 30 male rabbits, and prepared into reelpipes for autologous transplantation into the rabbit back muscular tissues. Samples were collected to carry out elastic tensile mechanical detection and histological observation. The maximum longitudinal tensile displacement of scrotal skin before 8 weeks of transplantation was greater than that after 8 weeks of transplantation (P < 0.05). The expression intensities of MMP-2 and TIMP-2 in the oral mucosa and in scrotal skin at 2 W time point were higher than those at T _o time point (P < 0.05). The expression quantities of TIMP-2 in oral mucosa and scrotal skin during 8-24 W were higher than those of MMP-2 (P < 0.05). At 8 W time point, the TIMP-2/MMP-2 ratio in scrotal skin was higher than that in oral mucosa (P < 0.05). MMP-2 and TIMP-2 expression in normal oral mucosa and scrotal skin is weak, but their expression is remarkably up-regulated after 2 weeks of transplantation, revealing that scar formation was related to the high expression of MMP-2 and TIMP-2. At the 8th-24th weeks, the AOD values of TIMP-2 in oral mucosa and scrotal skin are apparently higher than those of MMP-2; moreover, the TIMP-2/MMP-2 ratio in scrotal skin at the 8th week was higher than that in oral mucosa, which can well explain the earlier scar formation in scrotal skin than in oral mucosa, and it also suggests that the different expression levels between TIMP-2 and MMP-2 may account for the important cause of scar formation.

Adipose-derived cellular and cell-derived regenerative therapies in dermatology and aesthetic rejuvenation

Cellular and cell-derived components of adipose-derived tissue for the purposes of dermatologic and aesthetic rejuvenation applications have become increasingly studied and integrated into clinical practice. These components include micro-fragmented fat (nanofat), the stromal vascular fraction (SVF), adipose-derived mesenchymal stem cells (ASC), and extracellular vesicles (EVs), which have all shown capability to repair, regenerate, and rejuvenate surrounding tissue. Various aesthetic applications including hair growth, scar reduction, skin ischemia-reperfusion recovery, and facial rejuvenation are reviewed. In particular, results from preclinical and clinical studies are discussed, with a focus on clarification of nomenclature.

Extensive CD34-to-CD90 Fibroblast Transition Defines Regions of Cutaneous Reparative, Hypertrophic, and Keloidal Scarring

BACKGROUND

CD90 fibroblasts have been described arising from and replacing the homeostatic CD34 network in scleroderma, but have not been specifically examined in other forms of cutaneous fibrosis.

OBJECTIVES

To address expression, timelines, and spatial relationships of CD90, CD34, and smooth muscle actin (SMA) expressing fibroblasts in scars and to examine for the presence of a CD34-to-CD90 transition.

METHODS

One hundred and seventeen scars (reparative/hypertrophic/keloidal) were evaluated for CD90, CD34, and SMA expression. Double-staining immunohistochemistry for CD90/CD34 was performed to identify CD90/CD34 transitioning cells, confirmed by double-color immunofluorescence. In addition, some scars were double-stained with CD90/SMA, CD90/procollagen-1, or SMA/procollagen-1 to evaluate spatial relationships and active collagen synthesis. Expression was graded as diffuse, minority, and negative.

RESULTS

Most scars demonstrate a CD90/CD34 pattern, and dual CD90/CD34 fibroblasts were observed in 91% of scars. In reparative scars, CD90 expression reverses to a CD34/CD90 state with maturation. Pathologic scars exhibit prolonged CD90 expression. Both CD90 and SMA fibroblasts collagenize scars, although CD90 fibroblasts are more prevalent.

CONCLUSIONS

CD90 fibroblasts likely arise from the resting CD34 fibroblastic network. Actively collagenizing scar fibroblasts exhibit a CD90/CD34 phenotype, which is prolonged in pathologic scars. CD90 fibroblasts are likely important players in cutaneous scarring.

Gallic acid inhibits fibroblast growth and migration in keloids through the AKT/ERK signaling pathway

Keloids are a fibroproliferative disorder of the skin resulted from abnormal healing of injured or irritated skin and are characterized by the ability to spread beyond the original boundary of the wound. Here, we tested the effect of gallic acid (GA), a plant polyphenol with selective growth inhibitory effects in cancer, on the proliferation and invasion of keloid fibroblasts (KFs) isolated from patients undergoing surgery. GA inhibited KF proliferation, migration, and invasion in parallel with the downregulation of matrix metalloproteinase-1 and -3 and upregulation of tissue inhibitors of metalloproteinase-1. Flow cytometric analysis showed that GA inhibited cell cycle progression and induced apoptosis. The effects of GA on KFs occurred in parallel with the inhibition of AKT and ERK1/2, suggesting that GA acts by suppressing the AKT/ERK signaling pathway. In ex vivo explant cultures of keloid tissues, GA inhibited the migration of KFs to the wound area and suppressed the expression of angiogenic markers concomitant with the inhibition of collagen deposition. These results identify GA as a potential therapeutic agent for the treatment of keloids and suggest a potential mechanism underlying its protective effect.

Inhibiting function of human fetal dermal mesenchymal stem cells on bioactivities of keloid fibroblasts

BACKGROUND

Keloid is one kind of benign skin disease caused by hyperplasia of fibroblasts and collagen fibrils. It is refractory due to the lack of an effective treatment at present, which puts pressure on seeking a new therapeutic regimen. Mesenchymal stem cells (MSCs) from fetal skin are considered to play a crucial role in scarless healing. Nevertheless, the efficacy of them in keloid disorders remains poorly understood.

METHODS

Keloid fibroblasts (KFs), human adult dermal fibroblasts (ADFs), and human fetal dermal mesenchymal stem cells (FDMSCs) were isolated to single cells and cultured in Dulbecco's modified Eagle's medium (DMEM). ADFs and FDMSCs were used to generate ADF-conditioned medium (A-CM) and FDMSC-conditioned medium (F-CM). The effects of A-CM and F-CM on KFs were tested using MTT assay, BrdU assay, TUNEL assay, quantitative polymerase chain reaction, Western blot, and annexin V-FITC/PI binding assay,.

RESULTS

FDMSCs inhibited the bioactivity of KFs, downregulated the expression of the antiapoptotic protein BCL-2, and upregulated the expression of the proapoptotic protein BAX of KFs by secreting some soluble substances, thus accelerating the apoptosis of KFs.

CONCLUSION

F-CM induces apoptosis of KFs, providing a novel treatment strategy for keloid disorders.

The influence of genistein on free radicals in normal dermal fibroblasts and keloid fibroblasts examined by EPR spectroscopy

Normal and keloid fibroblasts were examined using X-band (9.3 GHz) electron paramagnetic resonance spectroscopy. The effect of genistein on the concentration of free radicals in both normal dermal and keloid fibroblasts after ultraviolet irradiation was investigated. The highest concentration of free radicals was seen in keloid fibroblasts, with normal fibroblasts containing a lower concentration. The concentration of free radicals in both normal and keloid fibroblasts was altered in a concentration-dependent manner by the presence of genistein. The change in intra-cellular free radical concentration after the ultraviolet irradiation of both normal and keloid fibroblasts is also discussed. The antioxidant properties of genistein, using its 1,1-Diphenyl-2-picrylhydrazyl (DPPH) free radical-scavenging activity as a model, were tested, and the effect of ultraviolet irradiation on its interaction with free radicals was examined. The electron paramagnetic resonance spectra of DPPH showed quenching by genistein. The interaction of genistein with DPPH free radicals in the absence of ultraviolet irradiation was shown to be slow, but this interaction was much faster under ultraviolet irradiation. Ultraviolet irradiation enhanced the free radical-scavenging activity of genistein.

TIEG1 Represses Smad7-Mediated Activation of TGF-β1/Smad Signaling in Keloid Pathogenesis

Transforming growth factor-β (TGF-β)/Smad signaling plays a key role in excessive fibrosis and keloid formations. Smad7 is a negative feedback regulator that prevents activation of TGF-β/Smad signaling. However, the regulatory mechanism for Smad7 in the keloid pathogenic process remains elusive. Here, we show that expression of TIEG1 is markedly higher in keloid fibroblasts, whereas protein, mRNA, and promoter activity levels of Smad7 are decreased. When TIEG1 was knocked down with small interfering RNA, both the promoter activity and protein expression of Smad7 were increased, whereas collagen production and the proliferation, migration, and invasion of keloid fibroblasts were decreased. In contrast, TIEG1 overexpression led to a decrease in Smad7 expression and Smad7 promoter activity. Upon TGF-β1 stimulation, TIEG1 promoted Smad2 phosphorylation by down-regulating Smad7. Luciferase reporter assays and chromatin immunoprecipitation assays further showed that TIEG1 can directly bind a GC-box/Sp1 site located between nucleotides -1392 and -1382 in the Smad7 promoter to repress Smad7 promoter activity. Taken together, these findings show that TIEG1 is highly expressed in human keloids and that it directly binds and represses Smad7 promoter-mediated activation of TGF-β/Smad2 signaling, thus providing clues for development of TIEG1 blocking strategies for therapy or prophylaxis of keloids.

Biopolymeric agents for skin wrinkle treatment

Skin aging is caused by several factors capable of deteriorating dermal matrix and is visibly noticed in skin color and skin contour deformities. In addition to the prevention of skin aging by application of antioxidants and sunscreens, treatment of skin wrinkles with those of dermal fillers is also recommended. Dermal filler products with enhanced injectability and longer duration are being developed continuously. Biodegradable polymers such as skin elastic fibers and dermal matrix mimetic used for treatment of skin wrinkle are summarized in this article. Additionally, the importance of amino acids, enzymes, and proteins in aesthetic of skin is addressed. Thus, elective agents are proposed for the dermatologists, cosmetic formulators, and the individuals facing skin aging problems. The candidate natural peptides from marine sources are additionally presented for widening the choice of actives application for treating aging.

Causal network analysis of head and neck keloid tissue identifies potential master regulators

OBJECTIVES/HYPOTHESIS

To generate novel insights and hypotheses in keloid development from potential master regulators.

STUDY DESIGN

Prospective cohort.

METHODS

Six fresh keloid and six normal skin samples from 12 anonymous donors were used in a prospective cohort study. Genome-wide profiling was done previously on the cohort using the Infinium HumanMethylation450 BeadChip (Illumina, San Diego, CA). The 190 statistically significant CpG islands between keloid and normal tissue mapped to 152 genes (P < .05). The top 10 statistically significant genes (VAMP5, ACTR3C, GALNT3, KCNAB2, LRRC61, SCML4, SYNGR1, TNS1, PLEKHG5, PPP1R13-α, false discovery rate <.015) were uploaded into the Ingenuity Pathway Analysis software's Causal Network Analysis (QIAGEN, Redwood City, CA). To reflect expected gene expression direction in the context of methylation changes, the inverse of the methylation ratio from keloid versus normal tissue was used for the analysis. Causal Network Analysis identified disease-specific master regulator molecules based on downstream differentially expressed keloid-specific genes and expected directionality of expression (hypermethylated vs. hypomethylated).

RESULTS

Causal Network Analysis software identified four hierarchical networks that included four master regulators (pyroxamide, tributyrin, PRKG2, and PENK) and 19 intermediate regulators.

CONCLUSIONS

Causal Network Analysis of differentiated methylated gene data of keloid versus normal skin demonstrated four causal networks with four master regulators. These hierarchical networks suggest potential driver roles for their downstream keloid gene targets in the pathogenesis of the keloid phenotype, likely triggered due to perturbation/injury to normal tissue.

LEVEL OF EVIDENCE

NA Laryngoscope, 126:E319-E324, 2016.

[FUNCTIONING PROTEASES IN THE ESOPHAGUS MUCOSA AFTER CHEMICAL BURNS]

The main result of esophagus burn is the formation of scars, that caused by excessive synthesis of collagen and changes the balance of metalloproteinases and their tissue inhibitors. It was studied the activity of proteolytic enzymes, participation of MMP (metalloproteinase) and their tissue inhibitors (TIMP) in alkali burns of the esophagus 1st and 2nd degrees. We have shown a significant increase of TIMP level in homogenate after alkali burns of the esophagus (an average of 31-56% depend on of burn degree). We observed a reduced activity of serine proteinase after 1st degree burns on 15th, 21st day 35 and 18% respectively, after burns 2nd degree on 15th, 21st day 54 and 50%. The decrease of activity MMP after 1st degree burns on 15th and 21st day 30, 19%, respectively, in conditions of chemical burns 2nd degree on 15th and 21st day 30, 37%. These data may indicate the development of scarring after burn simulation of 2nd degree. Further investigation of the MMP and TIMP in the process of wound healing can be useful in creating effective approaches to prevent formation of post scarring of the esophagus.

Extracellular matrix remodeling in equine sarcoid: an immunohistochemical and molecular study

BACKGROUND

Equine sarcoids are locally invasive, fibroblastic benign skin tumors. Bovine papillomavirus type-1 (BPV-1) and/or Bovine papillomavirus type-2 (BPV-2) are believed to be the causative agent of sarcoids, although the mechanisms by which the virus induce the tumor are still poorly understood. We hypothesized that in genetically predisposed equines latent BPV infection may be reactivated by immunosoppression and/or mechanical injury leading to a form of pathologic wound which may transform into a sarcoid. In this study, we investigated in 25 equine sarcoids and in five normal skin samples the histological features and evaluated the immunohistochemical and molecular expression of type I and type III Collagen, vimentin (VIM), alfa Smooth Muscle Actin (α-SMA), Matrix Metalloproteinase (MMPs) -2, 9, 14 and tissue inhibitor of metalloproteinase 2 (TIMP-2).

RESULTS

In 64% of investigated sarcoids, type I collagen staining was stronger than that of type III collagen. In 80% of sarcoids, SFs were strongly positive for vimentin and negative for α-SMA; the remaining sarcoid samples (20%) showed 70-80% of SFs labeled for vim and approximately 20-30% labeled for α-SMA. Moreover, all sarcoid specimen showed a variable staining pattern (weak to moderate) for MMP-9 and MMP-14, and a moderate to strong staining for MMP-2 and TIMP-2. Biochemical analysis confirmed immunohistochemical results and showed in sarcoids, for the first time, the cleaved form of MMP9, the 35 KDa active species for MMP-9.

CONCLUSIONS

This study revealed that in equine sarcoids exhibit an altered turnover of the Extracellular Matrix (ECM) deposition and degradation, as result of an altered expression of MMPs and TIMPs. Therefore, these observations seem to confirm that the basic mechanism for growth of equine sarcoids could be a neoplastic transformation during wound healing.

Hsp70 Knockdown by siRNA Decreased Collagen Production in Keloid Fibroblasts

PURPOSE

There are currently no consistently effective treatments for the excessive collagen produced by keloid fibroblasts. Previously, we reported that heat shock protein 70 (Hsp70) is up-regulated in keloid fibroblasts and keloid tissue. We, therefore, investigated whether Hsp70 is related to excessive collagen production in keloid fibroblasts.

MATERIALS AND METHODS

We inhibited Hsp70 in keloid fibroblasts by RNA interference and examined the resulting collagen expression. Thus, we selected small interfering RNAs (siRNAs) specific for human Hsp70, transfected them into keloid fibroblasts, and evaluated the resulting phenotypes and protein production using real-time polymerase chain reaction (PCR), Western blot, and a collagen assay.

RESULTS

The siRNAs dramatically suppressed Hsp70 mRNA expression, resulting in a decrease in collagen production in the keloid fibroblasts compared with controls. The siRNAs did not influence the viability of the keloid fibroblasts.

CONCLUSION

Hsp70 overexpression likely plays an important role in the excessive collagen production by keloid fibroblasts. RNA interference has therapeutic potential for the treatment of keloids.

Tissue Inhibitor of Metalloproteinase-2 Suppresses Collagen Synthesis in Cultured Keloid Fibroblasts

BACKGROUND

Keloids are defined as a kind of dermal fibroproliferative disorder resulting from the accumulation of collagen. In the remodeling of extracellular matrix, the balance between matrix metalloproteinases (MMPs) and the tissue inhibitors of metalloproteinases (TIMPs) is as critical as the proper production of extracellular matrix. We investigate the role of TIMPs and MMPs in the pathogenesis of keloids and examine the therapeutic potential of TIMP-2.

METHODS

The expression of TIMPs and MMPs in most inflamed parts of cultured keloid fibroblasts (KFs) and peripheral normal skin fibroblasts (PNFs) in the same individuals and the reactivity of KFs to cyclic mechanical stretch were analyzed by quantitative real-time polymerase chain reaction and enzyme-linked immunosorbent assay (n = 7). To evaluate the effect of treating KFs with TIMP-2, collagen synthesis was investigated by quantitative real-time polymerase chain reaction and enzyme-linked immunosorbent assay, and microscopic analysis was used to examine the treatment effects of TIMP-2 on ex vivo cultures of keloid tissue (n = 6).

RESULTS

TIMP-2 was downregulated in cultured KFs compared with PNFs in the same individuals, and the reduction in TIMP-2 was exacerbated by cyclic mechanical stretch. Administration of TIMP-2 (200 or 300 ng/mL) significantly suppressed expression of Col1A2 and Col3A1 mRNA and collagen type I protein in KFs. TIMP-2 also significantly reduced the skin dermal and collagen bundle thickness in ex vivo cultures of keloid tissue.

CONCLUSION

These results indicated that downregulation of TIMP-2 in KFs is a crucial event in the pathogenesis of keloids, and the TIMP-2 would be a promising candidate for the treatment of keloids.

High-mobility Group Box Protein-1, Matrix Metalloproteinases, and Vitamin D in Keloids and Hypertrophic Scars

Keloids and hypertrophic scars represent excessive wound healing involving high production of collagen by skin fibroblasts. This review focuses on the role of high-mobility group box protein-1 (HMGB-1), matrix metalloproteinases (MMPs), and vitamin D in these conditions. Although the role of HMGB-1 in keloids and hypertrophic scars is unclear, the effect of HMGB-1 on fibroblasts suggests a profibrotic role and a potential contribution to excessive scarring. MMPs contribute extensively to wound healing and characteristically degrade the extracellular matrix. MMP-1 is decreased in keloids and hypertrophic scars. However, other MMPs, including MMP-2, have been found to be increased and are thought to possibly contribute to keloid expansion through peripheral extracellular matrix catabolism. Many novel therapeutic approaches to keloids and hypertrophic scars target MMPs and aim to increase their levels and catabolic activity. The higher prevalence of keloids in darker skin types may partially be due to a tendency for lower vitamin D levels. The physiologically active form of vitamin D, 1,25(OH)2D3, inhibits the proliferation of keloid fibroblasts, and correlations between vitamin D receptor polymorphisms, such as the TaqI CC genotype, and keloid formation have been reported. Additionally, vitamin D may exert an antifibrotic effect partially mediated by MMPs. Here, we critically discuss whether keloid and hypertrophic scar formation could be predicted based on vitamin D status and vitamin D receptor polymorphisms. Specifically, the findings identified HMGB-1, MMPs, and vitamin D as potential avenues for further clinical investigation and potentially novel therapeutic approaches to prevent the development of keloids and hypertrophic scars.

Effect of collagen nanotopography on keloid fibroblast proliferation and matrix synthesis: implications for dermal wound healing

Keloids are locally exuberant dermal scars characterized by excessive fibroblast proliferation and matrix accumulation. Although treatment strategies include surgical removal and intralesional steroid injections, an effective regimen is yet to be established due to a high rate of recurrence. The regressing center and growing margin of the keloid have different collagen architecture and also differ in the rate of proliferation. To investigate whether proliferation is responsive to collagen topography, keloid, scar, and dermal fibroblasts were cultured on nanopatterned scaffolds varying in collagen fibril diameter and alignment-small and large diameter, aligned and random fibrils, and compared to cells grown on flat collagen-coated substrates, respectively. Cell morphology, proliferation, and expression of six genes related to proliferation (cyclin D1), phenotype (α-smooth muscle actin), and matrix synthesis (collagens I and III, and matrix metalloproteinase-1 and -2) were measured to evaluate cell response. Fibril alignment was shown to reduce proliferation and matrix synthesis in all three types of fibroblasts. Further, keloid cells were found to be most responsive to nanotopography.

The anti-scar effects of basic fibroblast growth factor on the wound repair in vitro and in vivo

Hypertrophic scars (HTS) and keloids are challenging problems. Their pathogenesis results from an overproduction of fibroblasts and excessive deposition of collagen. Studies suggest a possible anti-scarring effect of basic fibroblast growth factor (bFGF) during wound healing, but the precise mechanisms of bFGF are still unclear. In view of this, we investigated the therapeutic effects of bFGF on HTS animal model as well as human scar fibroblasts (HSF) model. We show that bFGF promoted wound healing and reduced the area of flattened non-pathological scars in rat skin wounds and HTS in the rabbit ear. We provide evidence of a new therapeutic strategy: bFGF administration for the treatment of HTS. The scar elevation index (SEI) and epidermal thickness index (ETI) was also significantly reduced. Histological reveal that bFGF exhibited significant amelioration of the collagen tissue. bFGF regulated extracellular matrix (ECM) synthesis and degradation via interference in the collagen distribution, the α-smooth muscle actin (α-SMA) and transforming growth factor-1 (TGF-β1) expression. In addition, bFGF reduced scarring and promoted wound healing by inhibiting TGFβ1/SMAD-dependent pathway. The levels of fibronectin (FN), tissue inhibitor of metalloproteinase-1 (TIMP-1) collagen I, and collagen III were evidently decreased, and matrix metalloproteinase-1 (MMP-1) and apoptosis cells were markedly increased. These results suggest that bFGF possesses favorable therapeutic effects on hypertrophic scars in vitro and in vivo, which may be an effective cure for human hypertrophic scars.

Keloid fibroblasts are more sensitive to Wnt3a treatment in terms of elevated cellular growth and fibronectin expression

BACKGROUND

Current evidence suggests the potential role of Wnt signalling in keloids pathogenesis but such literature remains scanty. We hypothesize that Wnt signalling is upregulated in keloid fibroblasts (KFs) and this promotes cellular growth, migration and extracellular matrix (ECM) production in such fibroblasts.

OBJECTIVES

To verify the downregulation of secreted frizzled-related protein 1 (SFRP1), a Wnt inhibitor and test KFs sensitivity to Wnt3a treatment compared to NFs in terms of activation of Wnt/β-catenin, cellular growth, migration and ECM expressions. Next, to investigate if ectopic expression of SFRP1 and treatment of quercetin in KFs can reverse their phenotypes.

METHODS

Quantitative Real-time PCR and western blotting were used to verify SFRP1 expression in NFs and KFs. The fibroblasts were tested with Wnt3a conditioned media and its effects were tested for (1) the cells' sensitivity to direct Wnt signalling via the activation of TCF reporter assay and protein expression of β-catenin, (2) cellular growth, (3) cell migration and (4) expressions of ECM components. Finally KFs were stably transduced with SFRP1 and treated with 2 doses of quercetin.

RESULTS

Lower levels of SFRP1 were confirmed at mRNA and protein levels in KFs which partly explained their sensitivity to Wnt3a treatment in terms of higher Wnt activation, cellular growth and fibronectin expression. Interestingly, Wnt3a did not promote higher cell migration rate and increase in collagen I expression. Ectopic expression of SFRP1 and quercetin treatment was able to mitigate Wnt3a-mediated phenotype of KFs.

CONCLUSIONS

Using SFRP1 or inhibitors of Wnt signalling might be one of the therapeutic solutions to treat keloid scarring.

Extracellular matrix molecules implicated in hypertrophic and keloid scarring

Tissue regeneration repairs the fabric of the skin to maintain homeostasis after injury. The expression and proliferation of extracellular matrix (ECM) molecules in the dermis, mediated by a range of growth factors and cytokines, is a fundamental element of wound repair. Previous work focused on how these complex molecular mechanisms relate to the formation of raised dermal scars, including keloid and hypertrophic scars, characterized by excessive deposition of ECM molecules. However, the mechanisms in the wound repair pathway which lead to the differential expression and organization of ECM molecules observed in different types of scar tissue are not fully understood. To summarize what is known about the expression and composition of ECM molecules in abnormal scarring, an extensive search of the literature was conducted, focusing on keywords connected to skin scarring, hypertrophic scars and keloid disease. The transcription and translation of collagen I and III, fibronectin, laminin, periostin and tenascin are all increased in raised dermal scar tissue. However, hyaluronic acid, dermatopontin and decorin are decreased, and the expression and localisation of fibrillin and elastin fibres in the dermis are altered compared with normal skin and scars. Recent whole genome profiling and proteomic studies have led to the identification of regulatory elements with different expression profiles in hypertrophic and keloid tissue. If the mechanisms of raised dermal scar formation are to be elucidated and effective therapeutic treatments developed, an integrated approach to research is required, focussing on the interactions between ECM molecules, regulatory elements and pathways.

Wound healing properties of jojoba liquid wax: an in vitro study

AIM OF THE STUDY

The wound healing properties of jojoba (Simmondsia chinensis) liquid wax (JLW) were studied in vitro on HaCaT keratinocytes and human dermal fibroblasts, which are involved in wounded skin repair.

MATERIALS AND METHODS

JLW cytotoxicity was evaluated by the crystal violet staining and the neutral red uptake endpoint. Induction of wound healing by JLW was assessed by scratch wound assay on cell monolayers. The involvement of signaling pathways was evaluated by the use of the Ca(2+) chelator BAPTA and of kinase inhibitors, and by Western blot analysis of cell lysates using anti-phospho antibodies. Collagen and gelatinase secretion by cells were assayed by in-cell ELISA and zymography analysis, respectively.

RESULTS

Cytotoxicity assays showed that the toxic effects of JLW to these cells are extremely low. Scratch wound experiments showed that JLW notably accelerates the wound closure of both keratinocytes and fibroblasts. The use of inhibitors and Western blot revealed that the mechanism of action of JLW is strictly Ca(2+) dependent and requires the involvement of the PI3K-Akt-mTOR pathway and of the p38 and ERK1/2 MAPKs. In addition, JLW was found to stimulate collagen I synthesis in fibroblasts, while no effect was detected on the secretion of MMP-2 and MMP-9 gelatinases by HaCaT or fibroblasts.

CONCLUSIONS

Taken together, data provide a pharmacological characterization of JLW properties on skin cells and suggest that it could be used in the treatment of wounds in clinical settings.

Investigation of tumor-peritoneal interactions in the pathogenesis of peritoneal metastases using a novel ex vivo peritoneal model

BACKGROUND

Peritoneal metastasis occurs in up to 30% of patients with gastric cancer. The aim of this experimental study is to develop and validate a novel ex vivo model of the human peritoneum to better identify factors involved in the development of peritoneal metastasis in order to improve its management and prognosis.

METHODS

Peritoneal discs harvested from hernia sacs obtained at inguinal hernia surgery were suspended in media using Teflon rings. Viability of the tissue was investigated using MTS assay, light and scanning electron microscopy (LM and SEM) over 72 h. To assess validity of the model, phenotypic changes in tumor cells were investigated. Changes in matrix metalloproteinases (MMP)-2 and -9 activities in HGC and AGS gastric adenocarcinoma cells after co-culture were investigated using zymography. Modulation of tumor cell adhesion to peritoneum after exposure to heparin was assessed using a fluorometric adhesion assay. Analysis was performed using Kruskal-Wallis for multiple comparisons and Mann-Witney U for comparisons between each group.

RESULTS

MTS assay showed reduced viability after 72 h (P = 0.047, compared with 24 h). Mesothelial cell loss at 48 h was demonstrated by LM and SEM, confirming peritoneal viability for at least 24 h after tissue harvesting. Zymography confirmed increased MMP2 and -9 activities in tumor cells and peritoneal tissue during co-culture compared with controls, and heparin significantly reduced tumor cell adherence (P = 0.04), as observed in published in vivo models.

CONCLUSION

A validated complete model of peritoneum was developed that has shown potential to determine realistic mechanisms of peritoneal metastasis.

Platelet lysate modulates MMP-2 and MMP-9 expression, matrix deposition and cell-to-matrix adhesion in keratinocytes and fibroblasts

Cell-matrix interactions are an essential element of wound healing, while platelet derivatives are used in clinical settings for the treatment of chronic wounds. We used a platelet lysate (PL), which had been previously shown to accelerate in vitro the wounding of HaCaT keratinocytes and fibroblasts (J Cell Mol Med, 13, 2009, 2030; Br J Dermatol, 159, 2008, 537), to study the modulation of MMP-2 and MMP-9 collagenase expression, collagen type I and III production and syndecan-4 expression and rearrangement in these cells. Zymography and Western blot analyses showed that exposure to 20% (v/v) PL for 24 h induced an apparently ERK1/2- and p38-dependent, NF-kappaB-independent, translational upregulation of MMP-9 in HaCaT, while HaCaT MMP-2 and fibroblast collagenases were almost unaffected. The use of in-cell ELISA showed that PL induced an increase in the collagen III production of fibroblasts. In-cell ELISA and immunofluorescence microscopy revealed an increase in the expression of syndecan-4 and its rearrangement to form focal adhesions in both cell types after PL exposure. Taken together, data indicate that PL promotes keratinocyte epithelialization and regulates fibroblast matrix deposition, thus providing a molecular basis for the ability of this platelet derivative to heal severe and problematic wounds without leading to heavy scarring and keloid formation.

Increased expression of fibroblast activation protein-alpha in keloid fibroblasts: implications for development of a novel treatment option

Keloid scars are common benign fibroproliferative reticular dermal lesions with unknown etiology and ill-defined management with high rate of recurrence post surgery. The progression of keloids is characterized by increased deposition of extracellular matrix proteins, invasion into the surrounding healthy skin and inflammation. Fibroblasts are considered to be the key cellular mediators of fibrogenesis in keloid scars. Fibroblast activation protein alpha (FAP-α) and dipeptidyl peptidase IV (DPPIV) are proteases located at the plasma membrane promoting cell invasiveness and tumor growth and have been previously associated with keloid scars. Therefore, in this study we analyzed in further detail the expression of FAP-α in keloid fibroblasts compared to control skin fibroblasts. Dermal fibroblasts were obtained from punch-biopsies from the active margin of four keloids and four control skin samples. Flow cytometry was used to analyze FAP-α expression and the CytoSelect 24-Well Collagen I Cell Invasion Assay was applied to study fibroblast invasion. Secretion of extracellular matrix (ECM) proteins was investigated by multiplexed particle-based flow cytometric assay and enzyme-linked immunosorbent assay. We found an increased expression of FAP-α in keloid fibroblasts compared to control skin fibroblasts (p < 0.001). Inhibition of FAP-α/DPPIV activity using the irreversible inhibitor H(2)N-Gly-Pro diphenylphosphonate reduced the increased invasiveness of keloid fibroblasts (p < 0.001) indicating that keloid invasion may be partly FAP-α/DPPIV mediated. FAP-α/DPPIV inhibition had no effect, (a) on the synthesis of the ECM proteins procollagen type I C-terminal peptide and fibronectin, (b) on the production of fibroblast growth factor or vascular endothelial growth factor, (c) on the expression of the proinflammatory cytokines interleukin-6 (IL-6), interleukin 8 (IL-8) or monocyte chemotactic protein-1. These results suggest a potential role for FAP-α and DPPIV in the invasive behavior of keloids. FAP-α and DPPIV may increase the invasive capacity of keloid fibroblasts rather than by modulating inflammation or ECM production. Since FAP-α expression is restricted to reactive fibroblasts in wound healing and normal adult tissues are generally FAP-α negative, inhibiting FAP-α/DPPIV activity may be a novel treatment option to prevent keloid progression.

Effect of transforming growth factor-beta1 antisense oligonucleotides on matrix metalloproteinases and their inhibitors in keloid fibroblasts

OBJECTIVE

To identify changes in the expression of matrixmetalloproteinases (MMPs) and their specific inhibitors tissue inhibitors of metalloproteinases (TIMPs) after targeting of transforming growth factor-beta1 (TGF-beta1) with antisense oligonucleotides.

STUDY DESIGN

Cross-sectional study.

SETTING

The study was performed on tissue samples from nine patients with keloid scars after otoplasty presenting to the Otolaryngology-Head and Neck Surgery Department of the University Hospital in Mannheim, Germany.

SUBJECTS AND METHODS

Keloid fibroblasts and normal fibroblasts were harvested from auricular keloid scars and healthy skin regions of the same patients during resection procedure of the keloid. Cells were placed in monolayer cultures. Expression of MMPs and TIMPs were analyzed by immunohistochemistry. The effect of TGF-beta1 targeting using antisense oligonucleotides on the expression of both protein groups in keloid-derived fibroblasts was analyzed by enzyme-linked immunosorbent assay and reverse-transcription polymerase chain reaction.

RESULTS

Immunohistochemical investigation demonstrated increased expression of MMP-2, -3, -9, and -13 and TIMP-1 and -2. TGF-beta1 antisense therapy significantly down-regulated MMP secretion in vitro.

CONCLUSION

Usage of TGF-beta1 antisense oligodeoxynucleotides (ODNs) may show a potential chemopreventive or therapeutic option for keloids by blocking the effect of TGF-beta1. Furthermore, antisense ODNs can be used as an investigative approach toward a better understanding of molecular mechanisms in keloid pathophysiology.