An ex vivo model employing keloid-derived cell-seeded collagen sponges for therapy development

Artificial keloid skin models: understanding the pathophysiological mechanisms and application in therapeutic studies

Keloid is a type of scar formed by the overexpression of extracellular matrix substances from fibroblasts following inflammation after trauma. The existing keloid treatment methods include drug injection, surgical intervention, light exposure, cryotherapy, etc. However, these methods have limitations such as recurrence, low treatment efficacy, and side effects. Consequently, studies are being conducted on the treatment of keloids from the perspective of inflammatory mechanisms. In this study, keloid models are created to understand inflammatory mechanisms and explore treatment methods to address them. While previous studies have used animal models with gene mutations, chemical treatments, and keloid tissue transplantation, there are limitations in fully reproducing the characteristics of keloids unique to humans, and ethical issues related to animal welfare pose additional challenges. Consequently, studies are underway to create in vitro artificial skin models to simulate keloid disease and apply them to the development of treatments for skin diseases. In particular, herein, scaffold technologies that implement three-dimensional (3D) full-thickness keloid models are introduced to enhance mechanical properties as well as biological properties of tissues, such as cell proliferation, differentiation, and cellular interactions. It is anticipated that applying these technologies to the production of artificial skin for keloid simulation could contribute to the development of inflammatory keloid treatment techniques in the future.

Chondroitinase as a therapeutic enzyme: Prospects and challenges

The chondroitinases (Chase) are bacterial lyases that specifically digest chondroitin sulfate and/or dermatan sulfate glycosaminoglycans via a β-elimination reaction and generate unsaturated disaccharides. In recent decades, these enzymes have attracted the attention of many researchers due to their potential applications in various aspects of medicine from the treatment of spinal cord injury to use as an analytical tool. In spite of this diverse spectrum, the application of Chase is faced with several limitations and challenges such as thermal instability and lack of a suitable delivery system. In the current review, we address potential therapeutic applications of Chase with emphasis on the challenges ahead. Then, we summarize the latest achievements to overcome the problems by considering the studies carried out in the field of enzyme engineering, drug delivery, and combination-based therapy.

UCHL1 aggravates skin fibrosis through an IGF-1-induced Akt/mTOR/HIF-1α pathway in keloid

Keloid is a heterogeneous disease featured by the excessive production of extracellular matrix. It is a great challenge for both clinicians and patients regarding the exaggerated and uncontrolled outgrowth and the therapeutic resistance of the disease. In this study, we verified that UCHL1 was drastically upregulated in keloid fibroblasts. UCHL1 had no effects on cell proliferation and migration, but instead promoted collagen I and α-SMA expression that was inhibited by silencing UCHL1 gene and by adding in LDN-57444, a pharmacological inhibitor for UCHL1 activity as well. The pathological process was mediated by IGF-1 promoted Akt/mTOR/HIF-1α signaling pathway because inhibition of any of them could reduce the expression of collagen I and α-SMA driven by UCHL1 in fibroblasts. Also, we found that UCHL1 expression in keloid fibroblasts was promoted by M2 macrophages via TGF-β1. These findings extend our understanding of the pathogenesis of keloid and provide potential therapeutic targets for the disease.

Study on Long-Term Tracing of Fibroblasts on Three-Dimensional Tissue Engineering Scaffolds Based on Graphene Quantum Dots

In order to find a convenient and stable way to trace human skin fibroblasts (HSFs) in three-dimensional tissue engineering scaffolds for a long time, in this experiment, Graphene Oxide Quantum Dots (GOQDs), Amino Graphene Quantum Dots (AGQDs) and Carboxyl Graphene Quantum Dots (CGQDs) were used as the material source for labeling HSFs. Exploring the possibility of using it as a long-term tracer of HSFs in three-dimensional tissue engineering scaffolds, the contents of the experiment are as follows: the HSFs were cultured in a cell-culture medium composed of three kinds of Graphene Quantum Dots for 24 h, respectively; (1) using Cell Counting Kit 8 (CCK8), Transwell migration chamber and Phalloidin-iFlior 488 to detect the effect of Graphene Quantum Dots on the biocompatibility of HSFs; (2) using a living cell workstation to detect the fluorescence labeling results of three kinds of Graphene Quantum Dots on HSFs, and testing the fluorescence attenuation of HSFs for 7 days; (3) the HSFs labeled with Graphene Quantum Dots were inoculated on the three-dimensional chitosan demethylcellulose sodium scaffold, and the living cell workstation was used to detect the spatial distribution of the HSFs on the three-dimensional scaffold through the fluorescence properties of the HSFs.. Experimental results: (1) the results of CCK8, Transwell migration, and FITC-Phalloidin cytoskeleton test showed that the three kinds of Graphene Quantum Dots had no effect on the biological properties of HSFs (p < 0.05); (2) the results of the fluorescence labeling experiment showed that only AGQDs could make HSFs fluorescent, and cells showed orange−red fluorescence; (3) the results of long-range tracing of HSFs which were labeled by with AGQDs showed that the fluorescence life of the HSFs were as long as 7 days; (4) The spatial distribution of HSFs can be detected on the three-dimensional scaffold based on their fluorescence properties, and the detection time can be up to 7 days.

Emerging therapeutic role of chondroitinase (ChABC) in neurological disorders and cancer

Abstract:

Proteoglycans are essential biomacromolecules that participate in matrix structure and organization, cell proliferation and migration, and cell surface signal transduction. However, their roles in physiology, particularly in CNS remain incompletely deciphered. Numerous studies highlight the elevated levels of chondroitin sulphate proteoglycans (CSPGs) in various diseases like cancers and neurological disorders like spinal cord injury (SCI), traumatic brain damage, neurodegenerative diseases, and are mainly implicated to hinder tissue repair. In such a context, chondroitinase ABC (ChABC), a therapeutic enzyme has shown immense hope to treat these diseases in several preclinical studies, primarily attributed to the digestion of the side chains of the proteoglycan chondroitin sulphate (CS) molecule. Despite extensive research, the progress in evolving the concept of therapeutic targeting of proteoglycans is still in its infancy. This review thus provides fresh insights into the emerging therapeutic applications of ChABC in various diseases apart from SCI and the underlying mechanisms.

Multifaceted array-based keloidal gene expression profiling reveals specific MDFI upregulation in keloid lesions

BACKGROUND

Keloid lesions are characterized by mesenchymal cell proliferation and excessive extracellular matrix deposition. Previous microarray analyses have been performed to investigate the mechanism of keloid development. However, the molecular pathology that contributes to keloid development remains obscure.

AIM

To explore the underlying essential molecules of keloids using microarrays.

METHODS

We performed microarray analyses of keloid and nonlesional skin tissues both in vivo and in vitro. Gene expression levels were compared between tissues and cells. Quantitative reverse transcription (qRT)-PCR and immunohistochemical staining were used to determine the expression levels of molecules of interest in keloid tissues.

RESULTS

Several common molecules were upregulated in both keloid tissues and keloid-lesional fibroblasts. PTPRD and NTM were upregulated both in vivo and in vitro. The genes MDFI and ITGA4 were located at the centre of the gene coexpression network analysis using keloid tissues. qRT-PCR revealed significant expression levels of PTPRD and MDFI in keloid tissues. Immunopathological staining revealed that MDFI-positive cells, which have fibroblast characteristics, were located in the keloid-associated lymphoid tissue (KALT) portion of the keloid tissue.

CONCLUSION

Our gene expression profiles of keloids could distinguish the difference between lesional tissue and cultured lesional fibroblasts, and MDFI was found to be commonly expressed in both tissues and cells. Thus, MDFI-positive cells, which were located in the KALT, may play an important role in keloid pathogenesis and thus might be useful for in vitro keloid studies.

The Keloid Disorder: Heterogeneity, Histopathology, Mechanisms and Models

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

Galectin-1 and Galectin-3 and Their Potential Binding Partners in the Dermal Thickening of Keloid Tissues

Keloids are defined histopathologically as an inflammatory disorder characterized by exhibiting numerous fibroblasts, abnormal vascularization, increased number of proinflammatory immune cells as well as uncontrolled cell proliferation, and exacerbated and disorganized deposition of extracellular matrix (ECM) molecules. Importantly, many of these ECM molecules display N- and O-linked glycan residues and are considered as potential targets for galectin-1 (Gal-1) and galectin-3 (Gal-3). Nevertheless, the presence and localization of Gal-1 and Gal-3 as well as the interactions with some of their binding partners in keloid tissues have not been considered. Here, we show that in the dermal thickening of keloids, versican, syndecan-1, fibronectin, thrombospondin-1, tenascin C, CD44, integrin β1, and N-cadherin were immunolocalized in the elongated fibroblasts that were close to the immune cell infiltrate, attached to collagen bundles, and around the microvasculature and in some immune cells. We also show that Gal-1 and Gal-3 were present in the cytoplasm and along the cell membrane of some fibroblasts and immune and endothelial cells of the dermal thickening. We suggest that Gal-1 and Gal-3, in concert with some of the ECM molecules produced by fibroblasts and by immune cells, counteract the inflammatory response in keloids. We also proposed that Gal-1 and Gal-3 through their binding partners may form a supramolecular structure at the cell surface of fibroblasts, immune cells, endothelial cells, and in the extracellular space that might influence the fibroblast morphology, adhesion, proliferation, migration, and survival as well as the inflammatory responses.

Multi-dimensional models for functional testing of keloid scars: In silico, in vitro, organoid, organotypic, ex vivo organ culture, and in vivo models

Keloid scars are described as benign fibro-proliferative dermal outgrowths that commonly occur in pigmented skin post cutaneous injury, and continue to grow beyond the boundary of the original wound margin. There is a lack of thorough understanding of keloid pathogenesis and thus keloid therapeutic options remain ill-defined. In view of the poor response to current therapy and high recurrence rates, there is an unmet need in improving our knowledge and therefore in identifying targeted and effective treatment strategies in management of keloids. Keloid research however, is hampered by a lack of relevant animal models as keloids do not spontaneously occur in animals and are unique to human skin. Therefore, developing novel animal models and nonanimal models for functional evaluation of keloid cells and tissue for better understanding their pathobiology and response to putative candidate therapies are essential. Here, we present the key concepts and relevant emerging research on two-dimensional and three-dimensional cell and tissue models for functional testing of keloid scars. We will describe in detail current models including in vitro mono- and co-cultures, multi-cellular spheroids (organoids) and organotyopic cultures, ex vivo whole skin keloid tissue organ culture models as well as in vivo human patient models. Finally, we discuss the role played by time as the fourth dimension in a novel model that involves sequential temporal biopsies of human patients with keloids (a so called 4D in vivo human model). The use of these unique models will no doubt prove pivotal in identification of new drug targets as well as biomarkers, in functional testing of emerging novel therapeutics, and in enhancing our understanding of keloid disease biology.

Regulation of fibrotic changes by the synergistic effects of cytokines, dimensionality and matrix: Towards the development of an in vitro human dermal hypertrophic scar model

Current therapeutic strategies to reduce scarring in full thickness skin defect offer limited success due to poor understanding of scar tissue formation and the underlying signaling pathways. There is an urgent need to develop human cell based in vitro scar tissue models as animal testing is associated with ethical and logistic complications and inter-species variations. Pro-inflammatory cytokines play critical role in regulating scar development through complex interplay and interaction with the ECM and corresponding signaling pathways. In this context, we assessed the responses of cultured fibroblasts with respect to their differentiation into myofibroblasts using optimised cytokines (TGF-β1, IL-6 and IL-8) for scar formation in 2D (tissue culture plate, collagen type I coated plate) vs 3D collagen type I gel based constructs. We attempted to deduce the role of dimensionality of cell culture matrix in modulating differentiation, function and phenotype of cultured fibroblasts. Validation of the developed model showed similarity to etiology and pathophysiology of in vivo hypertrophic scar with respect to several features: 1) transition of fibroblasts to myofibroblasts with convincing expression of α-SMA stress fibers; 2) contraction; 3) excessive collagen and fibronectin secretion; 4) expression of fibrotic ECM proteins (SPARC and Tenascin); 5) low MMP secretion. Most importantly, we elucidated the involvement of TGF-β/SMAD and Wnt/β-catenin pathways in developing in vitro dermal scar. Hence, this relatively simple in vitro human scar tissue equivalent may serve as an alternative for testing and designing of novel therapeutics and help in extending our understanding of the complex interplay of cytokines and related dermal scar specific signaling.

STATEMENT OF SIGNIFICANCE

Scarring of the skin affects almost millions of people per year in the developed world alone, nevertheless the complex pathophysiology and the precise signaling mechanisms responsible for this phenomenon of skin scarring are still unknown. A number of anti-scar drugs are being developed and being tested on animals and monolayer models. However, testing the efficacy of these drugs on lab based 3D in vitro models may prove extremely useful in recapitulating the 3D microenvironment of the native scar tissue. In that context in this study we have demonstrated the development of 3D in vitro dermal scar model, by optimizing a constellation of factors, such as combination of cytokines (TGF-β1,IL-6,IL-8) and cellular dimensionality in inducing the differentiation of dermal fibroblasts to myofibroblasts. This in vitro scar model was successful in replicating hallmark features of hypertrophic scar such as excessive synthesis of fibrotic extracellular matrix, perturbed matrix homeostasis, contraction, diminished MMP synthesis. The study also highlighted significant involvement of TGF-β/SMAD and Wnt/β-catenin signaling pathways in in vitro scar formation.

Labor prediction based on the expression patterns of multiple genes related to cervical maturation in human term pregnancy

PROBLEM

This study explored the possibility of evaluating cervical maturation using swabbed cervical cell samples at term pregnancy, and aimed to develop a novel approach to predict labor onset.

METHOD OF STUDY

Women with uncomplicated pregnancies (n=117 from 62 women at term pregnancy) were recruited. Messenger RNA expression levels of cervical cells for ten genes were quantified by qPCR. Principal component analysis (PCA) was conducted, and principal components that significantly contributed to the prediction of days to delivery were determined.

RESULTS

PCA demonstrated that 76% of the expression information from the ten genes can be represented by three principal components (PC1-3). By the multiple regression analysis, PC2 and Bishop score but not PC1 or PC3 were significant variables in the prediction of days to delivery.

CONCLUSION

These findings support the concurrent assessment of multiple gene activities in cervical cells as a promising approach to predict the initiation of labor.

Reconstitution of Human Keloids in Mouse Skin

Supplemental Digital Content is available in the text.

Background:

Keloids are a dermal fibroproliferative scar of unknown etiology. There is no good animal model for the study of keloids, which hinders the development and assessment of treatments for keloids.

Methods:

Human keratinocytes and dermal fibroblasts were isolated from 3 human skin tissues: normal skin, white scars, and keloids. A mixed-cell slurry containing keratinocytes and dermal fibroblasts was poured into a double chamber implanted on the back of NOD/Shi-scid/IL-2Rγnull mice. After 12 weeks, the recipient mice had developed reconstituted human skin tissues on their backs. These were harvested for histological studies.

Results:

Macroscopically, the reconstituted skins derived from both normal skin and white scars were similar to normal skin and white scars in humans, respectively. Keloid-derived reconstituted skins exhibited keloid-like hypertrophic nodules. Histological findings and immunohistochemical staining confirmed that the reconstituted skin tissues were of human origin and the keloid-derived reconstituted skin had the typical features of human keloids such as a hypertrophic dermal nodule, collagen type composition, orientation of collagen fibers, and versican expression.

Conclusion:

The mouse model with humanized keloid tissue presented here should be a useful tool for future keloid research.

Keloids: Animal models and pathologic equivalents to study tissue fibrosis

Animal models are crucial for the study of fibrosis. Keloids represent a unique type of fibrotic scarring that occurs only in humans, thus presenting a challenge for those studying the pathogenesis of this disease and its therapeutic options. Here, several animal models of fibrosis currently in use are described, emphasizing recent progress and highlighting encouraging challenges.

Glycosaminoglycan and versican deposits in taxane-induced sclerosis

Docetaxel and paclitaxel are widely used in the treatment of various malignant neoplasms. Taxane-induced sclerosis is dose-dependent and usually not generalized. Little information on the pathogenesis of scleroderma is currently available. Here, we report a case of generalized scleroderma and a case of early-stage oedematous sclerosis, both of which presented with intense versican deposits after administration of taxane for angiosarcoma.

COL11A1/(pro)collagen 11A1 expression is a remarkable biomarker of human invasive carcinoma-associated stromal cells and carcinoma progression

The COL11A1 human gene codes for the α1 chain of procollagen 11A1 and mature collagen 11A1, an extracellular minor fibrillar collagen. Under regular conditions, this gene and its derived products are mainly expressed by chondrocytes and mesenchymal stem cells as well as osteoblasts. Normal epithelial cells and quiescent fibroblasts from diverse locations do not express them. Mesenchyme-derived tumors and related conditions, such as scleroderma and keloids, are positive for COL11A1/(pro)collagen 11A1 expression, as well as high-grade human gliomas/glioblastomas. This expression is almost absent in benign pathological processes such as breast hyperplasia, sclerosing adenosis, idiopathic pulmonary fibrosis, cirrhosis, pancreatitis, diverticulitis, and inflammatory bowel disease. By contrast, COL11A1/(pro)collagen 11A1 is highly expressed by activated stromal cells of the desmoplastic reaction of different human invasive carcinomas, and this expression is correlated with carcinoma aggressiveness and progression, and lymph node metastasis. COL11A1 upregulation has been shown to be associated to TGF-β1, Wnt, and Hh signaling pathways, which are especially active in cancer-associated stromal cells. At the front of invasive carcinomas, neoplastic epithelial cells, putatively undergoing epithelial-to-mesenchymal transition, and carcinoma-derived cells with highly metastatic capabilities, can express COL11A1. Thus, in established metastases, the expression of COL11A1/(pro)collagen 11A1 could rely on both the metastatic epithelial cells and/or the accompanying activated stromal cells. COL11A1/(pro)collagen 11A1 expression is a remarkable biomarker of human carcinoma-associated stromal cells and carcinoma progression.

Chondroitinase: A promising therapeutic enzyme

Even after 20 years of granting orphan status for chondroitinase by US FDA, there is no visible outcome in terms of clinical use. The reasons are many. One of them could be lack of awareness regarding the biological application of the enzyme. The biological activity of chondroitinase is due to its ability to act on chondroitin sulfate proteoglycans (CSPGs). CSPGs are needed for normal functioning of the body. An increase or decrease in the level of CSPGs results in various pathological conditions. Chondroitinase is useful in conditions where there is an increase in the level of CSPGs, namely spinal cord injury, vitreous attachment and cancer. Over the last decade, various animal studies showed that chondroitinase could be a good drug candidate. Research focusing on developing a suitable carrier system for delivering chondroitinase needs to be carried out so that pharmacological activity observed in vitro and preclinical studies could be translated to clinical use. Further studies on distribution of chondroitinase as well need to be focused so that chondroitinase with desired attributes could be discovered. The present review article discusses about various biological applications of chondroitinase, drug delivery systems to deliver the enzyme and distribution of chondroitinase among microbes.

The preliminary study of effects of tolfenamic Acid on cell proliferation, cell apoptosis, and intracellular collagen deposition in keloid fibroblasts in vitro

Keloid scarring is a fibroproliferative disorder due to the accumulation of collagen type I. Tolfenamic acid (TA), a nonsteroidal anti-inflammatory drug, has been found to potentially affect the synthesis of collagen in rats. In this preliminary study, we aimed to test the effects of TA on cell proliferation, cell apoptosis, and the deposition of intracellular collagen in keloid fibroblasts. Normal fibroblasts (NFs) and keloid fibroblasts (KFs) were obtained from human dermis tissue. Within the dose range 10⁻³–10⁻⁶ M and exposure times 24 h, 48 h, and 72 h, we found that 0.55 × 10⁻³ M TA at 48 h exposure exhibited significantly decreased cell proliferation in both NFs and KFs. Under these experimental conditions, we demonstrated that (1) TA treatment induced a remarkable apoptotic rate in KFs compared to NFs; (2) TA treatment reduced collagen production in KFs versus NFs; (3) TA treatment decreased collagen type I expression in KFs comparing to that of NFs. In summary, our data suggest that TA decreases cell proliferation, induces cell apoptosis, and inhibits collagen accumulation in KFs.

Models of abnormal scarring

Keloids and hypertrophic scars are thick, raised dermal scars, caused by derailing of the normal scarring process. Extensive research on such abnormal scarring has been done; however, these being refractory disorders specific to humans, it has been difficult to establish a universal animal model. A wide variety of animal models have been used. These include the athymic mouse, rats, rabbits, and pigs. Although these models have provided valuable insight into abnormal scarring, there is currently still no ideal model. This paper reviews the models that have been developed.

Chondroitinase injection improves keloid pathology by reorganizing the extracellular matrix with regenerated elastic fibers

Keloids are a proliferative fibrotic disease characterized by abnormal accumulation of extracellular matrix in the dermis. Keloid lesions lack skin plasticity due to deficiencies in elastic fiber formation in the extracellular matrix. The loss of elastic fiber is caused by excessive accumulation of chondroitin sulfate (CS), a sulfated glycosaminoglycan. However, there is no radical cure for keloids. Using a model system, we show herein that treatment of keloid tissues with chondroitinase ABC, an enzyme that specifically digests CS, improves clinical features of keloids. Keloid tissues obtained from patients were grafted on nude mice, and chondroitinase ABC was injected into the grafted keloid tissues. Chondroitinase ABC treatment significantly reduced the volume of keloid implants concomitant with recovery of elastic fiber formation. These results suggest that chondroitinase ABC injection is an effective therapy for keloid.