Exosomes and microRNAs: insights into their roles in thermal-induced skin injury, wound healing and scarring.

A burn is a type of injury to the skin or other tissues caused by heat, chemicals, electricity, sunlight, or radiation. Burn injuries have been proven to have the potential for long-term detrimental effects on the human body. The conventional therapeutic approaches are not able to effectively and easily heal these burn wounds completely. The main potential drawbacks of these treatments include hypertrophic scarring, contracture, infection, necrosis, allergic reactions, prolonged healing times, and unsatisfactory cosmetic results. The existence of these drawbacks and limitations in current treatment approaches necessitates the need to search for and develop better, more efficient therapies. The regenerative potential of microRNAs (miRNAs) and the exosomal miRNAs derived from various cell types, especially stem cells, offer advantages that outweigh traditional burn wound healing treatment procedures. The use of multiple types of stem cells is gaining interest due to their improved healing efficiency for various applications. Stem cells have several key distinguishing characteristics, including the ability to promote more effective and rapid healing of burn wounds, reduced inflammation levels at the wound site, and less scar tissue formation and fibrosis. In this review, we have discussed the stages of wound healing, the role of exosomes and miRNAs in improving thermal-induced wounds, and the impact of miRNAs in preventing the formation of hypertrophic scars. Research studies, pre-clinical and clinical, on the use of different cell-derived exosomal miRNAs and miRNAs for the treatment of thermal burns have been documented from the year 2000 up to the current time. Studies show that the use of different cell-derived exosomal miRNAs and miRNAs can improve the healing of burn wounds. The migration of exosomal miRNAs to the site of a wound leads to inhibition of apoptosis, induction of autophagy, re-epithelialization, granulation, regeneration of skin appendages, and angiogenesis. In conclusion, this study underscores the importance of integrating miRNA and exosome research into treatment strategies for burn injuries, paving the way for novel therapeutic approaches that could significantly improve patient outcomes and recovery times.

Matricellular protein CCN1 promotes collagen alignment and scar integrity after myocardial infarction.

BACKGROUND: Members of the cellular communication network family (CCN) of matricellular proteins, like CCN1, have long been implicated in the regulation of cellular processes underlying wound healing, tissue fibrogenesis, and collagen dynamics. While many studies suggest antifibrotic actions for CCN1 in the adult heart through the promotion of myofibroblast senescence, they largely relied on exogenous supplementation strategies in in vivo models of cardiac injury where its expression is already induced-which may confound interpretation of its function in this process. The objective of this study was to interrogate the role of the endogenous protein on fibroblast function, collagen structural dynamics, and its associated impact on cardiac fibrosis after myocardial infarction (MI). METHODS/RESULTS: Here, we employed CCN1 loss-of-function methodologies, including both in vitro siRNA-mediated depletion and in vivo fibroblast-specific knockout mice to assess the role of the endogenous protein on cardiac fibroblast fibrotic signaling, and its involvement in acute scar formation after MI. In vitro depletion of CCN1 reduced cardiac fibroblast senescence and proliferation. Although depletion of CCN1 decreased the expression of collagen processing and stabilization enzymes (i.e., P4HA1, PLOD1, and PLOD2), it did not inhibit myofibroblast induction or type I collagen synthesis. Alone, fibroblast-specific removal of CCN1 did not negatively impact ventricular performance or myocardial collagen content but did contribute to disorganization of collagen fibrils and increased matrix compliance. Similarly, Ccn1 ablated animals subjected to MI showed no discernible alterations in cardiac structure or function one week after permanent coronary artery ligation, but exhibited marked increases in incidence of mortality and cardiac rupture. Consistent with our findings that CCN1 depletion does not assuage myofibroblast conversion or type I collagen synthesis in vitro, Ccn1 knockout animals revealed no measurable differences in collagen scar width or mass compared to controls; however, detailed structural analyses via SHG and TEM of scar regions revealed marked alterations in their scar collagen topography-exhibiting changes in numerous macro- and micro-level collagen architectural attributes. Specifically, Ccn1 knockout mice displayed heightened ECM structural complexity in post-MI scar regions, including diminished local alignment and heightened tortuosity of collagen fibers, as well as reduced organizational coherency, packing, and size of collagen fibrils. Associated with these changes in ECM topography with the loss of CCN1 were reductions in fibroblast-matrix interactions, as evidenced by reduced fibroblast nuclear and cellular deformation in vivo and reduced focal-adhesion formation in vitro; findings that ultimately suggest CCN1's ability to influence fibroblast-led collagen alignment may in part be credited to its capacity to augment fibroblast-matrix interactions. CONCLUSIONS: These findings underscore the pivotal role of endogenous CCN1 in the scar formation process occurring after MI, directing the appropriate arrangement of the extracellular matrix's collagenous components in the maturing scar-shaping the mechanical properties that support its structural stability. While this suggests an adaptive role for CCN1 in regulating collagen structural attributes crucial for supporting scar integrity post MI, the long-term protracted expression of CCN1 holds maladaptive implications, potentially diminishing collagen structural complexity and compliance in non-infarct regions.

Genetic influence on scar vascularity after burn injury in individuals of European ancestry: A prospective cohort study.

After burn injury there is considerable variation in scar outcome, partially due to genetic factors. Scar vascularity is one characteristic that varies between individuals, and this study aimed to identify genetic variants contributing to different scar vascularity outcomes. An exome-wide array association study and gene pathway analysis was performed on a prospective cohort of 665 patients of European ancestry treated for burn injury, using their scar vascularity (SV) sub-score, part of the modified Vancouver Scar Scale (mVSS), as an outcome measure. DNA was genotyped using the Infinium HumanCoreExome-24 BeadChip, imputed to the Haplotype Reference Consortium panel. Associations between genetic variants (single nucleotide polymorphisms) and SV were estimated using an additive genetic model adjusting for sex, age, % total body surface area and number of surgical procedures, utilising linear and multinomial logistic regression. No individual genetic variants achieved the cut-off threshold for significance. Gene sets were also analysed using the Functional Mapping and Annotation (FUMA) platform, in which biological processes indirectly related to angiogenesis were significantly represented. This study suggests that SNPs in genes associated with angiogenesis may influence SV, but further studies with larger datasets are essential to validate these findings.

Novel Fibrillar and Non-Fibrillar Collagens Involved in Fibrotic Scar Formation after Myocardial Infarction.

Following myocardial infarction (MI), adverse remodeling depends on the proper formation of fibrotic scars, composed of type I and III collagen. Our objective was to pinpoint the participation of previously unreported collagens in post-infarction cardiac fibrosis. Gene (qRT-PCR) and protein (immunohistochemistry followed by morphometric analysis) expression of fibrillar (types II and XI) and non-fibrillar (types VIII and XII) collagens were determined in RNA-sequencing data from 92 mice undergoing myocardial ischemia; mice submitted to permanent (non-reperfused MI, n = 8) or transient (reperfused MI, n = 8) coronary occlusion; and eight autopsies from chronic MI patients. In the RNA-sequencing analysis of mice undergoing myocardial ischemia, increased transcriptomic expression of collagen types II, VIII, XI, and XII was reported within the first week, a tendency that persisted 21 days afterwards. In reperfused and non-reperfused experimental MI models, their gene expression was heightened 21 days post-MI induction and positively correlated with infarct size. In chronic MI patients, immunohistochemistry analysis demonstrated their presence in fibrotic scars. Functional analysis indicated that these subunits probably confer tensile strength and ensure the cohesion of interstitial components. Our data reveal that novel collagens are present in the infarcted myocardium. These data could lay the groundwork for unraveling post-MI fibrotic scar composition, which could ultimately influence patient survivorship.

Genetic determinants of renal scarring in children with febrile UTI.

BACKGROUND: Febrile urinary tract infections (UTIs) are among the most severe bacterial infections in infants, in which a subset of patients develops complications. Identifying infants at risk of recurrent infections or kidney damage based on clinical signs is challenging. Previous observations suggest that genetic factors influence UTI outcomes and could serve as predictors of disease severity. In this study, we conducted a nationwide survey of infant genotypes to develop a strategy for infection management based on individual genetic risk. Our aims were to identify genetic susceptibility variants for renal scarring (RS) and genetic host factors predisposing to dilating vesicoureteral reflux (VUR) and recurrent UTIs. METHODS: To assess genetic susceptibility, we collected and analyzed DNA from blood using exome genotyping. Disease-associated genetic variants were identified through bioinformatics analysis, including allelic frequency tests and odds ratio calculations. Kidney involvement was defined using dimercaptosuccinic acid (DMSA) scintigraphy. RESULTS: In this investigation, a cohort comprising 1087 infants presenting with their first episode of febrile UTI was included. Among this cohort, a subset of 137 infants who underwent DMSA scanning was subjected to gene association analysis. Remarkable genetic distinctions were observed between patients with RS and those exhibiting resolved kidney involvement. Notably, the genetic signature indicative of renal scarring prominently featured mitochondrial genes. CONCLUSIONS: In this nationwide study of genetic susceptibility to RS after febrile UTIs in infancy, we identified a profile dominated by mitochondrial polymorphisms. This profile can serve as a predictor of future complications, including RS and recurrent UTIs.

[Exploring the causality between intestinal flora and hyperplastic scars of human based on two-sample Mendelian randomization analysis].

Objective: To investigate the causality between intestinal flora and hypertrophic scars (HS) of human. Methods: This study was a study based on two-sample Mendelian randomization (TSMR) analysis. The data on intestinal flora (n=18 473) and HS (n=208 248) of human were obtained from the genome-wide association study database. Genetically variable genes at five levels (phylum, class, order, family, and genus) of known intestinal flora, i.e., single nucleotide polymorphisms (SNPs), were extracted as instrumental variables for linkage disequilibrium (LD) analysis. Human genotype-phenotype association analysis was performed using PhenoScanner V2 database to exclude SNPs unrelated to HS in intestinal flora and analyze whether the selected SNPs were weak instrumental variables. The causal relationship between intestinal flora SNPs and HS was analyzed through four methods of TSMR analysis, namely inverse variance weighted (IVW), MR-Egger regression, weighted median, and weighted mode. Scatter plots of significant results from the four aforementioned analysis methods were plotted to analyze the correlation between intestinal flora SNPs and HS. Both IVW test and MR-Egger regression test were used to assess the heterogeneity of intestinal flora SNPs, MR-Egger regression test and MR-PRESSO outlier test were used to assess the horizontal multiplicity of intestinal flora SNPs, and leave-one-out sensitivity analysis was used to determine whether HS was caused by a single SNP in the intestinal flora. Reverse TSMR analyses were performed for HS SNPs and genus Intestinimonas or genus Ruminococcus2, respectively, to detect whether there was reverse causality between them. Results: A total of 196 known intestinal flora, belonging to 9 phyla, 16 classes, 20 orders, 32 families, and 119 genera, were obtained, and multiple SNPs were obtained from each flora as instrumental variables. LD analysis showed that the SNPs of the intestinal flora were consistent with the hypothesis that genetic variation was strongly associated with exposure factors, except for rs1000888, rs12566247, and rs994794. Human genotype-phenotype association analysis showed that none of the selected SNPs after LD analysis was excluded and there were no weak instrumental variables. IVW, MR-Egger regression, weighted median, and weighted mode of TSMR analysis showed that both genus Intestinimonas and genus Ruminococcus2 were causally associated with HS. Among them, forest plots of IVW and MR-Egger regression analyses also showed that 16 SNPs (the same SNPs number of this genus below) of genus Intestinimonas and 15 SNPs (the same SNPs number of this genus below) of genus Ruminococcus2 were protective factors for HS. Further, IVW analysis showed that genus Intestinimonas SNPs (with odds ratio of 0.62, 95% confidence interval of 0.41-0.93, P<0.05) and genus Ruminococcus2 SNPs (with odds ratio of 0.62, 95% confidence interval of 0.40-0.97, P<0.05) were negatively correlated with the risk of HS. Scatter plots showed that SNPs of genus Intestinimonas and genus Ruminococcus2 were protective factors of HS. Both IVW test and MR-Egger regression test showed that SNPs of genus Intestinimonas (with Q values of 5.73 and 5.76, respectively, P>0.05) and genus Ruminococcus2 (with Q values of 13.67 and 15.61, respectively, P>0.05) were not heterogeneous. MR-Egger regression test showed that the SNPs of genus Intestinimonas and genus Ruminococcus2 had no horizontal multiplicity (with intercepts of 0.01 and 0.06, respectively, P>0.05); MR-PRESSO outlier test showed that the SNPs of genus Intestinimonas and genus Ruminococcus2 had no horizontal multiplicity (P>0.05). Leave-one-out sensitivity analysis showed that no single intestinal flora SNP drove the occurrence of HS. Reverse TSMR analysis showed no reverse causality between HS SNPs and genus Intestinimonas or genus Ruminococcus2 (with odds ratios of 1.01 and 0.99, respectively, 95% confidence intervals of 0.97-1.06 and 0.96-1.04, respectively, P>0.05). Conclusions: There is a causal relationship between intestinal flora and HS of human, in which genus Intestinimonas and genus Ruminococcus2 have a certain effect on inhibiting HS.

Dysfunctional latent transforming growth factor ß activation after corneal injury in a classical Ehlers-Danlos model.

Patients with classical Ehlers Danlos syndrome (cEDS) suffer impaired wound healing and from scars formed after injuries that are atrophic and difficult to close surgically. Haploinsufficiency in COL5A1 creates systemic morphological and functional alterations in the entire body. We investigated mechanisms that impair wound healing from corneal lacerations (full thickness injuries) in a mouse model of cEDS (Col5a1+/-). We found that collagen V reexpression in this model is upregulated during corneal tissue repair and that wound healing is delayed, impaired, and results in large atrophic corneal scars. We noted that in a matrix with a 50 % content of collagen V, activation of latent Transforming Growth Factor (TGF) ß is dysregulated. Corneal myofibroblasts with a haploinsufficiency of collagen V failed to mechanically activate latent TGF ß. Second harmonic imaging microscopy showed a disorganized, undulated, and denser collagen matrix in our Col5a1+/- model that suggested alterations in the extracellular matrix structure and function. We hypothesize that a regenerated collagen matrix with only 50 % content of collagen V is not resistant enough mechanically to allow adequate activation of latent TGF ß by fibroblasts and myofibroblasts.

MiR-29b Downregulation by p53/Sp1 Complex Plays a Critical Role in Bleb Scar Formation After Glaucoma Filtration Surgery.

Purpose: To investigate the function and mechanism of tumor protein p53 in pathological scarring after glaucoma filtration surgery (GFS) using human Tenon's fibroblasts (HTFs) and a rabbit GFS model. Methods: The expression of p53 in bleb scarring after GFS and transforming growth factor-ß (TGF-ß)-induced HTFs (myofibroblasts [MFs]) was examined by western blot and immunochemical analysis. The interaction between p53 and specificity protein 1 (Sp1) was investigated by immunoprecipitation. The role of p53 and Sp1 in the accumulation of collagen type I alpha 1 chain (COL1A1) and the migration of MFs was evaluated by western blot, quantitative real-time polymerase chain reaction (qRT-PCR), wound healing, and Transwell assay. The regulatory mechanisms among p53/Sp1 and miR-29b were detected via qRT-PCR, western blot, luciferase reporter assay, and chromatin immunoprecipitation assay. The therapeutic effect of mithramycin A, a specific inhibitor of Sp1, on scarring formation was evaluated in a rabbit GFS model. Results: p53 was upregulated in bleb scar tissue and MFs. p53 and Sp1 form a transcription factor complex that induces the accumulation of COL1A1 and promotes the migration of MFs through downregulation of miR-29b, a known suppressor of COL1A1. The p53/Sp1 axis inhibits miR-29b expression by the direct binding promoter of the miR-29b gene. Mithramycin A treatment attenuated bleb scar formation in vivo. Conclusions: The p53/Sp1/miR-29b signaling pathway plays a critical role in bleb scar formation after GFS. This pathway could be targeted for therapeutic intervention of pathological scarring after GFS. Translational Relevance: Our research indicates that inhibition of p53/Sp1/miR-29b is a promising therapeutic strategy for preventing post-GFS pathological scarring.

Decoding fibrosis in the human central nervous system.

Recent advancements in human tissue analyses and animal models have revealed that fibrotic scarring is a common response to various lesions in the central nervous system (CNS). Perivascular cells within the brain or spinal cord give rise to stromal fibroblasts that form fibrotic scar tissue. In this review, we summarize the current understanding of fibrotic scar formation in different CNS lesions and evaluate published human single-cell gene expression datasets to gather information on perivascular cells. Specifically, we highlight the classification of pericytes and fibroblast subtypes and compare the marker expression of perivascular cells across different datasets.

Value of genotyping and scar-phenotyping for VT ablation procedures in patients with nonischemic left ventricular cardiomyopathies.

INTRODUCTION: Variants of cardiomyopathy genes in patients with nonischemic cardiomyopathy (NICM) generate various phenotypes of cardiac scar and delayed enhancement cardiac magnetic resonance (DE-CMR) imaging which may impact ventricular tachycardia (VT) management. METHODS: The objective was to compare the findings of cardiomyopathy genetic testing on DE-CMR imaging and long-term outcomes among patients with NICM undergoing VT ablation procedures. Image phenotyping and genotyping were performed in a consecutive series of patients referred for VT ablation and correlated to survival free of VT. Scar depth index (SDI) (% of scar at 0-3 mm, 3-5 mm and >5 mm projected on the closest endocardial surface) was determined. RESULTS: Forty-three patients were included (11 women, 55 ± 14 years, ejection fraction (EF) 45 ± 16%) and were followed for 3.4 ± 2.9 years. Pathogenic variants (PV) were identified in 16 patients (37%) in the following genes: LMNA (n = 5), TTN (n = 5), DSP (n = 2), AMLS1 (n = 1), MYBPC3 (n = 1), PLN (n = 1), and SCN5A (n = 1). A ring-like septal scar (RLSS) pattern was more often seen in patients with pathogenic variants (66% vs 15%, p = .001). RLSS was associated with deeper seated scars (SDI >5 mm 30.6 ± 22.6% vs 12.4 ± 16.2%, p = .005), and increased VT recurrence (HR 5.7 95% CI[1.8-18.4], p = .003). After adjustment for age, sex, EF, and total scar burden, the presence of a PV remained independently associated with worse outcomes (HR 4.7 95% CI[1.22-18.0], p = .02). CONCLUSIONS: Preprocedural genotyping and scar phenotyping is beneficial to identify patients with a favorable procedural outcome. Some PVs are associated with an intramural, deeper seated scar phenotype and have an increase of VT recurrence after ablation.

MicroRNA-29a Mitigates Laminectomy-Induced Spinal Epidural Fibrosis and Gait Dysregulation by Repressing TGF-ß1 and IL-6.

Spinal epidural fibrosis is one of the typical features attributable to failed back surgery syndrome, with excessive scar development in the dura and nerve roots. The microRNA-29 family (miR-29s) has been found to act as a fibrogenesis-inhibitory factor that reduces fibrotic matrix overproduction in various tissues. However, the mechanistic basis of miRNA-29a underlying the overabundant fibrotic matrix synthesis in spinal epidural scars post-laminectomy remained elusive. This study revealed that miR-29a attenuated lumbar laminectomy-induced fibrogenic activity, and epidural fibrotic matrix formation was significantly lessened in the transgenic mice (miR-29aTg) as compared with wild-type mice (WT). Moreover, miR-29aTg limits laminectomy-induced damage and has also been demonstrated to detect walking patterns, footprint distribution, and moving activity. Immunohistochemistry staining of epidural tissue showed that miR-29aTg was a remarkably weak signal of IL-6, TGF-ß1, and DNA methyltransferase marker, Dnmt3b, compared to the wild-type mice. Taken together, these results have further strengthened the evidence that miR-29a epigenetic regulation reduces fibrotic matrix formation and spinal epidural fibrotic activity in surgery scars to preserve the integrity of the spinal cord core. This study elucidates and highlights the molecular mechanisms that reduce the incidence of spinal epidural fibrosis, eliminating the risk of gait abnormalities and pain associated with laminectomy.

Therapeutic Silencing of p120 in Fascia Fibroblasts Ameliorates Tissue Repair.

Deep skin wounds rapidly heal by mobilizing extracellular matrix and cells from the fascia, deep beneath the dermal layer of the skin, to form scars. Despite wounds being an extensively studied area and an unmet clinical need, the biochemistry driving this patch-like repair remains obscure. Lacking also are efficacious therapeutic means to modulate scar formation in vivo. In this study, we identify a central role for p120 in mediating fascia mobilization and wound repair. Injury triggers p120 expression, largely within engrailed-1 lineage-positive fibroblasts of the fascia that exhibit a supracellular organization. Using adeno-associated virus‒mediated gene silencing, we show that p120 establishes the supracellular organization of fascia engrailed-1 lineage-positive fibroblasts, without which fascia mobilization is impaired. Gene silencing of p120 in fascia fibroblasts disentangles their supracellular organization, reducing the transfer of fascial cells and extracellular matrix into wounds and augmenting wound healing. Our findings place p120 as essential for fascia mobilization, opening, to our knowledge, a previously unreported therapeutic avenue for targeted intervention in the treatment of a variety of skin scar conditions.

A novel CDKN1A-JAZF1 gene fusion in low-grade endometrial stromal sarcoma arising from endometriosis in abdominal wall cesarean section scar: A case report and literature review.

OBJECTIVE: We report a low-grade endometrial stromal sarcoma (ESS) with a novel CDKN1A-JAZF1 fusion gene arising from abdominal wall endometrioma. CASE REPORT: A 40-year-old woman presented with a 5.5-cm abdominal wall mass juxtaposed to the postoperative scar of two cesarean sections. Histologically, the tumor exhibited obvious tongue-like protrusions into the surrounding tissue, showed spindle cells with multinodular growth pattern that occasionally rotate around small arteries. Immunohistochemically, the tumor cells were positive for CD10, estrogen receptor (ER), progesterone receptor (PR), negatively stained for smooth muscle actin (SMA), CD117, CyclinD1. In addition, a previously undescribed gene fusion between CDNK1A 5' end of exon 1(NM_000389.5) and JAZF1 3' end of exon 5 (NM_175,061,3) was reported in this case. CONCLUSION: This report of ESS suggesting that rapidly growing abdominal wall masses without menstruation-related should be promptly evaluated and treated aggressively. In addition, we have expanded the molecular landscape of low-grade ESS.

Interaction between Cervical Microbiota and Host Gene Regulation in Caesarean Section Scar Diverticulum.

Cesarean section scar diverticulum (CSD) has become a formidable obstacle preventing women receiving CS from reproducing. However, the pathogenesis of CSD remains unexplored. In this study, we characterized the cervical microbiota, metabolome, and endometrial transcriptome of women with CSD. Based on the 16s rRNA results of cervical microbes, the microbial diversity in the CSD group was higher than that in the control group. Lactobacillus were significantly decreased in the CSD group and were mutually exclusive with potentially harmful species (Sphingomonas, Sediminbacterium, and Ralstonia) abnormally elevated in CSD. The microbiota in the CSD group exhibited low activity in carbohydrate metabolism and high activity in fatty acid metabolism, as confirmed by the metabolomic data. The metabolomic characterization identified 6,130 metabolites, of which 34 were significantly different between the two groups. In the CSD group, N-(3-hydroxy-eicosanoid)-homoserine lactone and Ternatin were significantly increased, in addition to the marked decrease in fatty acids due to high consumption. N-(3-hydroxy-eicosanoyl)-homoserine lactone is a regulator that promotes abnormal apoptosis in a variety of cells, including epithelial cells and vascular endothelial cells. This abnormal apoptosis of endometrial epithelial cells and neovascularization was also reflected in the transcriptome of the endometrium surrounding the CSD. In the endometrial transcriptome data, the upregulated genes in the CSD group were active in negatively regulating the proliferation of blood vessel endothelial cells, endothelial cells, and epithelial cells. This alteration in the host's endometrium is most likely influenced by the abnormal microbiota, which appears to be confirmed in the results by integrating host transcriptome and microbiome data. For the first time, this study described the abnormal activity characteristics of microbiota and the mechanism of host-microbiota interaction in CSD. IMPORTANCE Cesarean section scar diverticulum (CSD) has become a formidable obstacle preventing women receiving CS from reproducing. In this study, we revealed that potentially harmful microbes do have adverse effects on the host endometrium. The mechanism of these adverse effects includes the inhibition of the activity of beneficial bacteria such as lactobacilli, consumption of protective metabolites of the endometrium, and also the production of harmful metabolites. In the present study, we elucidated the mechanism from the perspectives of microbial, metabolic, and host responses, providing an important rationale to design preventive and therapeutic strategies for CSD.

In situ scarless skin healing of a severe human burn wound induced by a hCTLA4Ig gene-transferred porcine skin graft.

Preventing fibrosis or hypertrophic scar formation following tissue damage is still a big challenge despite the numerous approaches clinicians currently use. Hitherto, no written account was available of a successful case of scarless skin healing after a severe burn injury. Here, we report the first case of the "perfect regenerative healing" of a severe burn wound with no hypertrophic scar formation in which a postage stamp skin autograft was covered with human cytotoxic-T-lymphocyte associated antigen4-immunoglobulin (hCTLA4Ig) gene-transferred pig skin. We also discuss the mechanisms involved in the scarless healing of human burn wounds.

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.

Optimized RNA isolation of FFPE uterine scar tissues for RNA expression analyses delineated by laser microdissection.

Samples for histological analyses are often formalin-fixed paraffin-embedded (FFPE) and slide-mounted, which complicates RNA extraction for many downstream molecular applications. Furthermore, when the region of interest is extremely small due to isolation with laser microdissection (LMD), extracting RNA of adequate quality and quantity is difficult. We describe an optimized protocol for maximizing RNA output from FFPE tissue devised to identify and analyze gene expression of human maternal uterine scar tissue obtained from uterotomy scars resulting from prior cesarean deliveries. Gomori trichrome staining allowed for region identification for LMD. Successful RNA isolation, reverse transcription and, importantly, quantitative real-time PCR (qRT-PCR) were performed. This report provides an optimized step-by-step protocol yielding sufficient RNA for qRT-PCR analyses from challenging tissue/LMD-FFPE samples.

Emerging Evidence of Noncoding RNAs in Bleb Scarring after Glaucoma Filtration Surgery.

PURPOSE: To conduct a narrative review of research articles on the potential anti- and pro-fibrotic mechanisms of noncoding RNAs following glaucoma filtration surgery. METHODS: Keyword searches of PubMed, and Medline databases were conducted for articles discussing post-glaucoma filtration surgeries and noncoding RNA. Additional manual searches of reference lists of primary articles were performed. RESULTS: Fifteen primary research articles were identified. Four of the included papers used microarrays and qRT-PCR to identify up- or down-regulated microRNA (miRNA, miR) profiles and direct further study, with the remainder focusing on miRNAs or long noncoding RNAs (lncRNAs) based on previous work in other organs or disease processes. The results of the reviewed papers identified miR-26a, -29b, -139, -155, and -200a as having anti-fibrotic effects. In contrast, miRs-200b and -216b may play pro-fibrotic roles in filtration surgery fibrosis. lncRNAs including H19, NR003923, and 00028 have demonstrated pro-fibrotic effects. CONCLUSIONS: Noncoding RNAs including miRNAs and lncRNAs are emerging and promising therapeutic targets in the prevention of post-glaucoma filtration surgery fibrosis.

Allopurinol-induced severe cutaneous adverse reactions in Vietnamese: the role of HLA alleles and other risk factors.

Aim: To reveal the association of three class I HLA alleles, including HLA-A*33:03, HLA-B*58:01 and HLA-C*03:02, and allopurinol-induced severe cutaneous adverse reactions (SCARs) in Vietnamese patients. Methods: A case-control study on 100 allopurinol-induced SCARs patients, 183 tolerant controls and 810 population controls was performed. The HLA-A*33:03 and HLA-C*03:02 alleles were detected with the nested allele-specific PCR method; the HLA-B*58:01 allele was detected with the sequence-specific primer PCR method. Results: There were strong associations between HLA-B*58:01 and HLA-C*03:02 and allopurinol-induced SCARs. Specific associations were found between HLA-B*58:01 and Stevens-Johnson syndrome/toxic epidermal necrolysis and between HLA-C*03:02 and drug reaction with eosinophilia and systemic symptoms, with a gene dosage effect. The multivariate regression analysis indicated two significant independent risk factors: HLA-B*58:01/HLA-C*03:02 and estimated glomerular filtration rate <60 ml/min/1.73 m2. The specificity, positive predictive value and negative predictive value of HLA-B*58:01 testing were higher than the HLA-C*03:02 or the multiplex testing, especially in patients with impaired renal function. Conclusion: The results supported pre-treatment HLA-B*58:01 testing in Vietnamese patients with declined renal function to prevent SCARs.