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Genotype-phenotype associations in recessive dystrophic epidermolysis bullosa (RDEB) have been difficult to elucidate. To investigate RDEB genotype-phenotype associations and explore a functional approach to genotype classification. Clinical examination and genetic testing of RDEB subjects, including assessment of clinical disease by RDEB subtype and extent of blistering. Genotypes were evaluated according to each variant's effect on type VII collagen function per updated literature and subsequently categorized by degree of impact on VII collagen function as low-impact (splice/missense, missense/missense), medium-impact (premature termination codon [PTC]/missense, splice/splice), and high-impact (PTC/PTC, PTC/splice). Genotype-phenotype associations were investigated using Kruskal-Wallis and Fisher's exact tests, and age-adjusted regressions. Eighty-three participants were included. High-impact variants were associated with worse RDEB subtype and clinical disease, including increased prevalence of generalized blistering (55.6% for low-impact vs 72.7% medium-impact vs 90.4% high-impact variants, P =.002). In age-adjusted regressions, participants with high-impact variants had 40.8-fold greater odds of squamous cell carcinoma compared to low-impact variants (P =.02), and 5.7-fold greater odds of death compared to medium-impact variants (P =.05). Cross-sectional design. Functional genotype categories may stratify RDEB severity; high-impact variants correlated with worse clinical outcomes. Further validation in larger cohorts is needed. [ABSTRACT FROM AUTHOR]

Patients with recessive dystrophic epidermolysis bullosa (RDEB) experience numerous complications, which are exacerbated by inflammatory dysregulation and infection. Understanding the immunological mechanisms is crucial for selecting medications that balance inflammation control and immunocompetence. In this cross‐sectional study, aiming to identify potential immunotherapeutic targets and inflammatory biomarkers, we delved into the interrelationship between clinical severity and systemic inflammatory parameters in a representative RDEB cohort. Encompassing 84 patients aged 1–67 and spanning all three Epidermolysis Bullosa Disease Activity and Scarring Index (EBDASI) severity categories, we analysed the interrelationship of infection history, standard inflammatory markers, systemic cytokines and Ig levels to elucidate their roles in RDEB pathophysiology. Our findings identify C‐reactive protein as an excellent biomarker for disease severity in RDEB. A type 2 inflammatory profile prevails among moderate and severe RDEB patients, correlating with dysregulated circulating IgA and IgG. These results underscore the IL4/IL13 pathways as potential evidence‐based therapeutic targets. Moreover, the complete inflammatory scenario aligns with Staphylococcus aureus virulence mechanisms. Concurrently, abnormalities in IgG, IgE and IgM levels suggest an immunodeficiency state in a substantial number of the cohort's patients. Our results provide new insights into the interplay of infection and immunological factors in the pathogenesis of RDEB. [ABSTRACT FROM AUTHOR]

Secondary amyloidosis may complicate inherited dermatoses, but recessive dystrophic epidermolysis bullosa (RDEB) complicated by renal amyloidosis is rare. We report a case of a 12-year-old male child with RDEB presenting with progressive generalized anasarca for 20 days. Kidney biopsy showed diffuse expansion of mesangial matrix by pale acellular Periodic Acid-Schiff (PAS)-negative amorphous material, which was congophilic on Congo red stain and gave apple green birefringence on polarization and extending along the glomerular basement membrane, suggestive of amyloidosis. Genetic analysis showed a compound heterozygous pathogenic variant in the COL7A1 gene with autosomal recessive inheritance. [ABSTRACT FROM AUTHOR]

Recessive dystrophic epidermolysis bullosa (RDEB) is a severe skin fragility disorder caused by mutations in the COL7A1 gene, which encodes type VII collagen (COL7), the main constituent of anchoring fibrils for attaching the epidermis to the dermis. Persistent skin erosions frequently result in intractable ulcers in RDEB patients. Adipose-derived mesenchymal stromal cells (AD-MSCs) are easily harvested in large quantities and have low immunogenicity. Therefore, they are suitable for clinical use, including applications involving allogeneic cell transplantation. Keratinocyte-like cells transdifferentiated from AD-MSCs (KC-AD-MSCs) express more COL7 than undifferentiated AD-MSCs and facilitate skin wound healing with less contracture. Therefore, these cells can be used for skin ulcer treatment in RDEB patients. We investigated whether KC-AD-MSCs transplantation ameliorated the RDEB phenotype severity in the grafted skin of a RDEB mouse model (col7a1 -null) on the back of the immunodeficient mouse. KC-AD-MSCs were intradermally injected into the region surrounding the skin grafts, and this procedure was repeated after 7 days. After a further 7-day interval, the skin grafts were harvested. Neodeposition of COL7 and generation of anchoring fibrils at the dermal-epidermal junction were observed, although experiments were based on qualitative. KC-AD-MSCs may correct the COL7 insufficiency, repair defective/reduced anchoring fibrils, and improve skin integrity in RDEB patients. • KC-AD-MSCs are shown to be stratified and adhere each other by expressing desmosome-like structures. • KC-AD-MSCs-injected skin demonstrated predominantly suppressed blister formation. • Intradermal KC-AD-MSCs injection deposited COL7 at the dermal-epidermal junction. • KC-AD-MSCs have therapeutic potential for RDEB treatment. [ABSTRACT FROM AUTHOR]

Simple Summary: Recessive dystrophic epidermolysis bullosa (RDEB) is a rare and severe hereditary skin disease characterized by skin and mucosa fragility. RDEB patients are predisposed to the development of life-threatening cutaneous squamous cell carcinoma (SCC). In this study, we investigated the immune profiles of SCCs occurring in a cohort of RDEB patients and compared them with clinical, histopathological and prognostic features. We describe two distinct clinical outcomes in RDEB patients with cutaneous SCCs. A majority of RDEB patients had local and not rapidly life-threatening SCC, while others developed early aggressive and metastatic SCCs. The high-risk primary RDEB-SCC was associated with a tumor microenvironment displaying a higher neutrophil-to-lymphocyte infiltration ratio. Increased levels of citrullinated histone H3, a marker of neutrophil extracellular traps (NET), were detected in tumoral skin and in the serum of RDEB patients with high-risk primary SCC. Recessive dystrophic epidermolysis bullosa (RDEB) is a rare severe hereditary skin disease characterized by skin and mucosa fragility, resulting in blister formation. The most severe complication in RDEB patients is the development of cutaneous squamous cell carcinoma (SCC), leading to premature death. There is a great deal of evidence suggesting a permissive tumor microenvironment (TME) as a driver of SCC development in RDEB patients. In a cohort of RDEB patients, we characterized the immune profiles of RDEB-SCCs and compared them with clinical, histopathological, and prognostic features. RDEB-SCCs were subdivided into four groups based on their occurrence (first onset or recurrences) and grading according to clinical, histopathological parameters of aggressiveness. Thirty-eight SCCs from 20 RDEB patients were analyzed. Five RDEB patients experienced an unfavorable course after the diagnosis of the first SCC, with early recurrence or metastasis, whereas 15 patients developed multiple SCCs without metastasis. High-risk primary RDEB-SCCs showed a higher neutrophil-to-lymphocyte ratio in the tumor microenvironment and an increased proportion of neutrophil extracellular traps (NETs). Additionally, citrullinated histone H3, a marker of NETs, was increased in the serum of RDEB patients with high-risk primary SCC, suggesting that this modified form of histone H3 may serve as a potential blood marker of unfavorable prognosis in RDEB-SCCs. [ABSTRACT FROM AUTHOR]

Epidermolysis bullosa (EB) is a genodermatosis that lacks effective treatments and requires supportive care for its severe, life‐threatening manifestations. Bone marrow transplantation (BMT) and its derived cells have been suggested to improve clinical symptoms and quality of life. A comprehensive search was conducted for publications evaluating BMT and bone marrow‐derived mesenchymal stem cell (BM‐MSC) therapy for EB in PubMed/MEDLINE, Google Scholar, and Cochrane databases from inception until June 2023. A total of 55 participants with severe forms of EB had BMT and/or BM‐MSCs, with recessive dystrophic EB as the most common EB type; 53 (96.4%) patients had better wound healing, and 3 (5.5%) patients died of sepsis. The most common adverse events reported were graft failure, sepsis, graft‐versus‐host disease, and renal insufficiency. Allogeneic BMT is a high‐risk procedure with possible benefits and adverse events. BM‐MSCs revealed favorable outcomes to improve the safety of EB cell‐based therapy by minimizing the risk of serious adverse events, reducing blisters, and accelerating wound healing. Further studies are needed to assess the treatment's long‐term effects and clarify the risk/benefit ratio of procedure versus conventional therapy. [ABSTRACT FROM AUTHOR]

Abstract Background Invasive cutaneous squamous cell carcinomas (cSCC) are a leading cause of death in recessive dystrophic epidermolysis bullosa (RDEB), a rare blistering genodermatosis. Outcomes of RDEB-cSCC therapies have primarily been described in case reports. Systematic studies are scarce. This systematic review aims to assess the pathophysiology, clinical characteristics, and outcomes of RDEB-cSCCs, with a focus on results and mechanisms of recent immunotherapies and anti-EGFR treatments. Results A systematic literature search of epidermolysis bullosa and cSCC was performed in February 2024, using PubMed, Embase, Cochrane Central Register of Controlled Trials, ClinicalTrials.gov, and EudraCT databases. Cases with administration of systematic therapies and unpublished outcomes regarding death were tracked with corresponding authors. Data extraction and risk of bias assessment was performed by two independent reviewers. Of 1132 references in the original search, 163 relevant articles were identified, representing 59 case reports, 7 cohort studies, 49 abstracts, 47 in-vitro/in-vivo experiments, and 1 bioinformatic study. From these, 157 cases of RDEB-cSCCs were included. The majority of RDEB-cSCCs were well-differentiated (64.1%), ulcerated (59.6%), and at least 2 cm in size (77.6%), with a median age at diagnosis of 30 years old (range 6–68.4). Surgery was the primary form of treatment (n = 128), followed by chemotherapy and radiotherapy. Anti-EGFR therapy and immunotherapy was also reported beginning in 2009 and 2019, respectively. Survival time from first cSCC diagnosis to death was available in 50 cases. When stratified by their treatment regimen, median survival time was 1.85 years (surgery + chemotherapy, n = 6), 2 years (surgery only, n = 19), 4.0 years (+ anti-EFGR therapy, n = 10), 4 years (surgery + radiotherapy, n = 9), 4.6 years (+ immunotherapy, n = 4), and 9.5 years (surgery + chemotherapy + radiotherapy; n = 2). Treatment-related adverse events were primarily limited to impaired wound healing for immunotherapies and nausea and fatigue for anti-EGFR therapies. Conclusions Despite the challenges of a limited sample size in a rare disease, this systematic review provides an overview of treatment options for cSCCs in RDEB. When surgical treatment options have been exhausted, the addition of immunotherapy and/or anti-EGFR therapies may extend patient survival. However, it is difficult to attribute extended survival to any single treatment, as multiple therapeutic modalities are often used to treat RDEB-cSCCs.

Background: Invasive cutaneous squamous cell carcinomas (cSCC) are a leading cause of death in recessive dystrophic epidermolysis bullosa (RDEB), a rare blistering genodermatosis. Outcomes of RDEB-cSCC therapies have primarily been described in case reports. Systematic studies are scarce. This systematic review aims to assess the pathophysiology, clinical characteristics, and outcomes of RDEB-cSCCs, with a focus on results and mechanisms of recent immunotherapies and anti-EGFR treatments. Results: A systematic literature search of epidermolysis bullosa and cSCC was performed in February 2024, using PubMed, Embase, Cochrane Central Register of Controlled Trials, ClinicalTrials.gov, and EudraCT databases. Cases with administration of systematic therapies and unpublished outcomes regarding death were tracked with corresponding authors. Data extraction and risk of bias assessment was performed by two independent reviewers. Of 1132 references in the original search, 163 relevant articles were identified, representing 59 case reports, 7 cohort studies, 49 abstracts, 47 in-vitro/in-vivo experiments, and 1 bioinformatic study. From these, 157 cases of RDEB-cSCCs were included. The majority of RDEB-cSCCs were well-differentiated (64.1%), ulcerated (59.6%), and at least 2 cm in size (77.6%), with a median age at diagnosis of 30 years old (range 6–68.4). Surgery was the primary form of treatment (n = 128), followed by chemotherapy and radiotherapy. Anti-EGFR therapy and immunotherapy was also reported beginning in 2009 and 2019, respectively. Survival time from first cSCC diagnosis to death was available in 50 cases. When stratified by their treatment regimen, median survival time was 1.85 years (surgery + chemotherapy, n = 6), 2 years (surgery only, n = 19), 4.0 years (+ anti-EFGR therapy, n = 10), 4 years (surgery + radiotherapy, n = 9), 4.6 years (+ immunotherapy, n = 4), and 9.5 years (surgery + chemotherapy + radiotherapy; n = 2). Treatment-related adverse events were primarily limited to impaired wound healing for immunotherapies and nausea and fatigue for anti-EGFR therapies. Conclusions: Despite the challenges of a limited sample size in a rare disease, this systematic review provides an overview of treatment options for cSCCs in RDEB. When surgical treatment options have been exhausted, the addition of immunotherapy and/or anti-EGFR therapies may extend patient survival. However, it is difficult to attribute extended survival to any single treatment, as multiple therapeutic modalities are often used to treat RDEB-cSCCs. [ABSTRACT FROM AUTHOR]

Recessive dystrophic epidermolysis bullosa (RDEB) is a rare inherited skin disease characterized by defects in type VII collagen leading to a range of fibrotic pathologies resulting from skin fragility, aberrant wound healing, and altered dermal fibroblast physiology. Using a novel in vitro model of fibrosis based on endogenously produced extracellular matrix, we screened an FDA-approved compound library and identified antivirals as a class of drug not previously associated with anti-fibrotic action. Preclinical validation of our lead hit, daclatasvir, in a mouse model of RDEB demonstrated significant improvement in fibrosis as well as overall quality of life with increased survival, weight gain and activity, and a decrease in pruritus-induced hair loss. Immunohistochemical assessment of daclatasvir-treated RDEB mouse skin showed a reduction in fibrotic markers, which was supported by in vitro data demonstrating TGFβ pathway targeting and a reduction of total collagen retained in the extracellular matrix. Our data support the clinical development of antivirals for the treatment of patients with RDEB and potentially other fibrotic diseases. Synopsis: The antiviral daclatasvir was identified as an anti-fibrotic compound in a high throughput screen using a novel in vitro model of fibrosis. Daclatasvir improved life quality and survival in a mouse model of recessive dystrophic epidermolysis bullosa (RDEB). Endogenously-produced matrix from primary patient fibroblasts can be utilized as a detachment assay to screen compounds for anti-fibrotic repurposing. Antivirals are a novel class of fibrosis preventatives in RDEB as verified from two library screens. Daclatasvir was our repurposed hit of interest for preventing fibrosis in RDEB. Daclatasvir downregulated the TGFβ signaling pathway targets. Daclatasvir improved the life quality of RDEB mice. The antiviral daclatasvir was identified as an anti-fibrotic compound in a high throughput screen using a novel in vitro model of fibrosis. Daclatasvir improved life quality and survival in a mouse model of recessive dystrophic epidermolysis bullosa (RDEB). [ABSTRACT FROM AUTHOR]

Abstract Recessive dystrophic epidermolysis bullosa (RDEB) is a rare inherited skin disease characterized by defects in type VII collagen leading to a range of fibrotic pathologies resulting from skin fragility, aberrant wound healing, and altered dermal fibroblast physiology. Using a novel in vitro model of fibrosis based on endogenously produced extracellular matrix, we screened an FDA-approved compound library and identified antivirals as a class of drug not previously associated with anti-fibrotic action. Preclinical validation of our lead hit, daclatasvir, in a mouse model of RDEB demonstrated significant improvement in fibrosis as well as overall quality of life with increased survival, weight gain and activity, and a decrease in pruritus-induced hair loss. Immunohistochemical assessment of daclatasvir-treated RDEB mouse skin showed a reduction in fibrotic markers, which was supported by in vitro data demonstrating TGFβ pathway targeting and a reduction of total collagen retained in the extracellular matrix. Our data support the clinical development of antivirals for the treatment of patients with RDEB and potentially other fibrotic diseases.

Antisense oligonucleotides (ASOs) represent an emerging therapeutic platform for targeting genetic diseases by influencing various aspects of (pre-)mRNA biology, such as splicing, stability, and translation. In this study, we investigated the potential of modulating the splicing pattern in recessive dystrophic epidermolysis bullosa (RDEB) patient cells carrying a frequent genomic variant (c.425A > G) that disrupts splicing in the COL7A1 gene by using short 2′-O-(2-Methoxyethyl) oligoribo-nucleotides (2′-MOE ASOs). COL7A1-encoded type VII collagen (C7) forms the anchoring fibrils within the skin that are essential for the attachment of the epidermis to the underlying dermis. As such, gene variants of COL7A1 leading to functionally impaired or absent C7 manifest in the form of extensive blistering and wounding. The severity of the disease pattern warrants the development of novel therapies for patients. The c.425A > G variant at the COL7A1 exon 3/intron 3 junction lowers the efficiency of splicing at this junction, resulting in non-functional C7 transcripts. However, we found that correct splicing still occurs, albeit at a very low level, highlighting an opportunity for intervention by modulating the splicing reaction. We therefore screened 2′-MOE ASOs that bind along the COL7A1 target region ranging from exon 3 to the intron 3/exon 4 junction for their ability to modulate splicing. We identified ASOs capable of increasing the relative levels of correctly spliced COL7A1 transcripts by RT-PCR, sqRT-PCR, and ddPCR. Furthermore, RDEB-derived skin equivalents treated with one of the most promising ASOs exhibited an increase in full-length C7 expression and its accurate deposition along the basement membrane zone (BMZ). [ABSTRACT FROM AUTHOR]

Objective: Recessive dystrophic epidermolysis bullosa (RDEB) is a genetic skin fragility and ultimately lethal blisteringdisease caused by mutations in the COL7A1 gene which is responsible for coding type VII collagen. Investigating thepathological mechanisms and novel candidate therapies for RDEB could be fostered by new cellular models. Theaim of this study was to employ CRISPR/Cas9 technology in the development of immortalized COL7A1-deficientkeratinocyte cell lines intended for application as a cellular model for RDEB in ex vivo studies.Materials and Methods: In this experimental study, we used transient transfection to express COL7A1-targeting guideRNA (gRNA) and Cas9 in HEK001 immortalized keratinocyte cell line followed by enrichment with fluorescent-activatedcell sorting (FACS) via GFP expressing cells (GFP+ HEK001). Homogenous single-cell clones were then isolated,genotyped, and evaluated for type VII collagen expression. We performed a scratch assay to confirm the functionaleffect of COL7A1 knockout.Results: We achieved 46.1% (P

Recessive dystrophic epidermolysis bullosa (RDEB) is a rare severe hereditary skin disease characterized by skin and mucosa fragility, resulting in blister formation. The most severe complication in RDEB patients is the development of cutaneous squamous cell carcinoma (SCC), leading to premature death. There is a great deal of evidence suggesting a permissive tumor microenvironment (TME) as a driver of SCC development in RDEB patients. In a cohort of RDEB patients, we characterized the immune profiles of RDEB-SCCs and compared them with clinical, histopathological, and prognostic features. RDEB-SCCs were subdivided into four groups based on their occurrence (first onset or recurrences) and grading according to clinical, histopathological parameters of aggressiveness. Thirty-eight SCCs from 20 RDEB patients were analyzed. Five RDEB patients experienced an unfavorable course after the diagnosis of the first SCC, with early recurrence or metastasis, whereas 15 patients developed multiple SCCs without metastasis. High-risk primary RDEB-SCCs showed a higher neutrophil-to-lymphocyte ratio in the tumor microenvironment and an increased proportion of neutrophil extracellular traps (NETs). Additionally, citrullinated histone H3, a marker of NETs, was increased in the serum of RDEB patients with high-risk primary SCC, suggesting that this modified form of histone H3 may serve as a potential blood marker of unfavorable prognosis in RDEB-SCCs.

Objective: Recessive dystrophic epidermolysis bullosa (RDEB) is a genetic skin fragility and ultimately lethal blistering disease caused by mutations in the COL7A1 gene which is responsible for coding type VII collagen. Investigating the pathological mechanisms and novel candidate therapies for RDEB could be fostered by new cellular models. The aim of this study was to employ CRISPR/Cas9 technology in the development of immortalized COL7A1-deficient keratinocyte cell lines intended for application as a cellular model for RDEB in ex vivo studies. Materials and Methods: In this experimental study, we used transient transfection to express COL7A1-targeting guide RNA (gRNA) and Cas9 in HEK001 immortalized keratinocyte cell line followed by enrichment with fluorescent-activated cell sorting (FACS) via GFP expressing cells (GFP+ HEK001). Homogenous single-cell clones were then isolated, genotyped, and evaluated for type VII collagen expression. We performed a scratch assay to confirm the functional effect of COL7A1 knockout. Results: We achieved 46.1% (P<0.001) efficiency of in/del induction in the enriched transfected cell population. Except for 4% of single nucleotide insertions, the remaining in/dels were deletions of different sizes. Out of nine single expanded clones, two homozygous and two heterozygous COL7A1-deficient cell lines were obtained with defined mutation sequences. No off-target effect was detected in the knockout cell lines. Immunostaining and western blot analysis showed lack of type VII collagen (COL7A1) protein expression in these cell lines. We also showed that COL7A1-deficient cells had higher motility compared to their wild-type counterparts. Conclusion: We reported the first isogenic immortalized COL7A1-deficient keratinocyte lines that provide a useful cell culture model to investigate aspects of RDEB biology and potential therapeutic options. [ABSTRACT FROM AUTHOR]

Abstract Background Recessive Dystrophic Epidermolysis Bullosa (RDEB) is a rare inherited skin disease caused by variants in the COL7A1 gene, coding for type VII collagen (C7), an important component of anchoring fibrils in the basement membrane of the epidermis. RDEB patients suffer from skin fragility starting with blister formation and evolving into chronic wounds, inflammation and skin fibrosis, with a high risk of developing aggressive skin carcinomas. Restricted therapeutic options are limited by the lack of in vitro models of defective wound healing in RDEB patients. Results In order to explore a more efficient, non-invasive in vitro model for RDEB studies, we obtained patient fibroblasts derived from discarded dressings) and examined their phenotypic features compared with fibroblasts derived from non-injured skin of RDEB and healthy-donor skin biopsies. Our results demonstrate that fibroblasts derived from RDEB chronic wounds (RDEB-CW) displayed characteristics of senescent cells, increased myofibroblast differentiation, and augmented levels of TGF-β1 signaling components compared to fibroblasts derived from RDEB acute wounds and unaffected RDEB skin as well as skin from healthy-donors. Furthermore, RDEB-CW fibroblasts exhibited an increased pattern of inflammatory cytokine secretion (IL-1β and IL-6) when compared with RDEB and control fibroblasts. Interestingly, these aberrant patterns were found specifically in RDEB-CW fibroblasts independent of the culturing method, since fibroblasts obtained from dressing of acute wounds displayed a phenotype more similar to fibroblasts obtained from RDEB normal skin biopsies. Conclusions Our results show that in vitro cultured RDEB-CW fibroblasts maintain distinctive cellular and molecular characteristics resembling the inflammatory and fibrotic microenvironment observed in RDEB patients’ chronic wounds. This work describes a novel, non-invasive and painless strategy to obtain human fibroblasts chronically subjected to an inflammatory and fibrotic environment, supporting their use as an accessible model for in vitro studies of RDEB wound healing pathogenesis. As such, this approach is well suited to testing new therapeutic strategies under controlled laboratory conditions.

Recessive dystrophic epidermolysis bullosa (RDEB) is an autosomal monogenic skin disease caused by mutations in COL7A1 gene and lack of functional type VII collagen (C7). Currently, there is no cure for RDEB, and most of the gene therapies under development have been designed as ex vivo strategies because of the shortage of efficient and safe carriers for gene delivery. Herein, we designed, synthesized, and screened a new group of highly branched poly(β amino ester)s (HPAEs) as non-viral carriers for the delivery of plasmids encoding dual single-guide RNA (sgRNA)-guided CRISPR-Cas9 machinery to delete COL7A1 exon 80 containing the c.6527dupC mutation. The selected HPAEs (named PTTA-DATOD) showed robust transfection efficiency, comparable with or surpassing that of leading commercial gene transfection reagents such as Lipofectamine 3000, Xfect, and jetPEI, while maintaining negligible cytotoxicity. Furthermore, CRISPR-Cas9 plasmids delivered by PTTA-DATOD achieved efficient targeted deletion and restored bulk C7 production in RDEB patient keratinocyte polyclones. The non-viral CRISPR-Cas9-based COL7A1 exon deletion approach developed here has great potential to be used as a topical treatment for RDEB patients with mutations in COL7A1 exon 80. Besides, this therapeutic strategy can easily be adapted for mutations in other COL7A1 exons, other epidermolysis bullosa subtypes, and other genetic diseases.

Introduction: Epidermolysis bullosa (EB) is a group of genetic disorders characterized by fragility of the skin and mucosal membranes. Dystrophic EB (DEB) is caused by mutations in the gene coding for type VII collagen. Among the most frequent oral manifestations in Recessive DEB (RDEB) are oral ulcers and blisters, absence of tongue papillae and palatal rugae, ankyloglossia, oral vestibule obliteration, and microstomia. The following report describes a modified impression technique used in a patient with severe RDEB and severe microstomia to obtain models for orthodontic treatment with aligners. Case Report: A 25‐year‐old female patient with severe RDEB was referred for orthodontic treatment. Severe microstomia (8 mm), hindered the use of conventional trays or intraoral scanners to design the aligners. Therefore, a contracture release surgery in combination with a modified impression technique was performed to obtain an optimal impression and subsequent aligners for orthodontic treatment. Discussion: This case presents an alternative strategy to provide orthodontic treatment with aligners in patients with severe microstomia due to severe RDEB. Reports of orthodontic treatment in people living with EB, especially in RDEB, are still rare, with few publications about fixed braces, early teeth extraction and removable devices, and none using aligners. Most of the impression techniques reported are aimed at oral rehabilitation. The multidisciplinary approach and impression technique reported should broaden the alternatives of orthodontic techniques provided to patients with EB and severe microstomia. Conclusions: This article describes an oral contracture release surgery and modified impression technique for obtaining good quality impression for the design of orthodontic aligners in patients with severe microstomia due to severe RDEB. [ABSTRACT FROM AUTHOR]

• ABCB5+ MSCs facilitated wound closure in recessive dystrophic epidermolysis bullosa. • The wounds that closed during treatment showed a prolonged time to recurrence. • Wounds that did not reach full closure during treatment decreased in size. Recessive dystrophic epidermolysis bullosa (RDEB) is a hereditary, rare, devastating and life-threatening skin fragility disorder with a high unmet medical need. In a recent international, single-arm clinical trial, treatment of 16 patients (aged 6–36 years) with three intravenous infusions of 2 × 106 immunomodulatory ABCB5+ dermal mesenchymal stromal cells (MSCs)/kg on days 0, 17 and 35 reduced disease activity, itch and pain. A post-hoc analysis was undertaken to assess the potential effects of treatment with ABCB5+ MSCs on the overall skin wound healing in patients suffering from RDEB. Documentary photographs of the affected body regions taken on days 0, 17, 35 and at 12 weeks were evaluated regarding proportion, temporal course and durability of wound closure as well as development of new wounds. Of 168 baseline wounds in 14 patients, 109 (64.9%) wounds had closed at week 12, of which 63.3% (69 wounds) had closed already by day 35 or day 17. Conversely, 74.2% of the baseline wounds that had closed by day 17 or day 35 remained closed until week 12. First-closure ratio within 12 weeks was 75.6%. The median rate of newly developing wounds decreased significantly (P = 0.001) by 79.3%. Comparison of the findings with published data from placebo arms and vehicle-treated wounds in controlled clinical trials suggests potential capability of ABCB5+ MSCs to facilitate wound closure, prolongate wound recurrence and decelerate formation of new wounds in RDEB. Beyond suggesting therapeutic efficacy for ABCB5+ MSCs, the analysis might stimulate researchers who develop therapies for RDEB and other skin fragility disorders to not only assess closure of preselected target wounds but pay attention to the patients' dynamic and diverse overall wound presentation as well as to the durability of achieved wound closure and the development of new wounds. Clinicaltrials.gov NCT03529877; EudraCT 2018-001009-98. [ABSTRACT FROM AUTHOR]

Recessive dystrophic epidermolysis bullosa (RDEB) is a rare and severe hereditary skin disease, caused by mutations in the COL7A1. However, whether non‐invasive prenatal testing (NIPT) can be used for this monogenic genodermatosis remains unknown. Accordingly, we conducted a study in which one couple at high risk of having a fetus with RDEB were recruited and tested by haplotyping‐based NIPT. Next‐generation sequencing‐based multi‐gene panel testing was carried out in this couple and their first child as proband who was affected with RDEB. We deduced parental haplotypes via single nucleotide polymorphism (SNP)‐based haplotype linkage analysis. Then the maternal plasma cell‐free DNA was also sequenced to determine the fetal haplotypes using a parental haplotype‐assisted hidden Markov model (HMM) analysis. Results show that the fetus was only a heterozygous mutation carrier in COL7A1 and the identical results were obtained after birth. These results demonstrate that haplotyping‐based NIPT is a feasible method for NIPT of RDEB. [ABSTRACT FROM AUTHOR]

Abstract Background Anemia is a common complication of severe forms of epidermolysis bullosa (EB). To date, there are no guidelines outlining best clinical practices to manage anemia in the EB population. The objective of this manuscript is to present the first consensus guidelines for the diagnosis and management of anemia in EB. Results Due to the lack of high-quality evidence, a consensus methodology was followed. An initial survey exploring patient preferences, concerns and symptoms related to anemia was sent to EB patients and their family members. A second survey was distributed to EB experts and focused on screening, diagnosis, monitoring and management of anemia in the different types of EB. Information from these surveys was collated and used by the panel to generate 26 consensus statements. Consensus statements were sent to healthcare providers that care for EB patients through EB-Clinet. Statements that received more than 70% approval (completely agree/agree) were adopted. Conclusions The end result was a series of 6 recommendations which include 20 statements that will help guide management of anemia in EB patients. In patients with moderate to severe forms of EB, the minimum desirable level of Hb is 100 g/L. Treatment should be individualized. Dietary measures should be offered as part of management of anemia in all EB patients, oral iron supplementation should be used for mild anemia; while iron infusion is reserved for moderate to severe anemia, if Hb levels of > 80–100 g/L (8–10 g/dL) and symptomatic; and transfusion should be administered if Hb is

Antisense oligonucleotides (ASOs) represent an emerging therapeutic platform for targeting genetic diseases by influencing various aspects of (pre-)mRNA biology, such as splicing, stability, and translation. In this study, we investigated the potential of modulating the splicing pattern in recessive dystrophic epidermolysis bullosa (RDEB) patient cells carrying a frequent genomic variant (c.425A > G) that disrupts splicing in the COL7A1 gene by using short 2′-O-(2-Methoxyethyl) oligoribo-nucleotides (2′-MOE ASOs). COL7A1-encoded type VII collagen (C7) forms the anchoring fibrils within the skin that are essential for the attachment of the epidermis to the underlying dermis. As such, gene variants of COL7A1 leading to functionally impaired or absent C7 manifest in the form of extensive blistering and wounding. The severity of the disease pattern warrants the development of novel therapies for patients. The c.425A > G variant at the COL7A1 exon 3/intron 3 junction lowers the efficiency of splicing at this junction, resulting in non-functional C7 transcripts. However, we found that correct splicing still occurs, albeit at a very low level, highlighting an opportunity for intervention by modulating the splicing reaction. We therefore screened 2′-MOE ASOs that bind along the COL7A1 target region ranging from exon 3 to the intron 3/exon 4 junction for their ability to modulate splicing. We identified ASOs capable of increasing the relative levels of correctly spliced COL7A1 transcripts by RT-PCR, sqRT-PCR, and ddPCR. Furthermore, RDEB-derived skin equivalents treated with one of the most promising ASOs exhibited an increase in full-length C7 expression and its accurate deposition along the basement membrane zone (BMZ).

Recessive dystrophic epidermolysis (RDEB) is a rare, inherited, and currently incurable skin blistering disorder characterized by cyclically recurring wounds coexisting with chronic non-healing wounds. In a recent clinical trial, three intravenous infusions of skin-derived ABCB5+ mesenchymal stromal cells (MSCs) to 14 patients with RDEB improved the healing of wounds that were present at baseline. Since in RDEB even minor mechanical forces perpetually provoke the development of new or recurrent wounds, a post-hoc analysis of patient photographs was performed to specifically assess the effects of ABCB5+ MSCs on new or recurrent wounds by evaluating 174 wounds that occurred after baseline. During 12 weeks of systemic treatment with ABCB5+ MSCs, the number of newly occurring wounds declined. When compared to the previously reported healing responses of the wounds present at baseline, the newly occurring wounds healed faster, and a greater portion of healed wounds remained stably closed. These data suggest a previously undescribed skin-stabilizing effect of treatment with ABCB5+ MSCs and support repeated dosing of ABCB5+ MSCs in RDEB to continuously slow the wound development and accelerate the healing of new or recurrent wounds before they become infected or progress to a chronic, difficult-to-heal stage. [ABSTRACT FROM AUTHOR]

Background: Recessive Dystrophic Epidermolysis Bullosa (RDEB) is a rare inherited skin disease caused by variants in the COL7A1 gene, coding for type VII collagen (C7), an important component of anchoring fibrils in the basement membrane of the epidermis. RDEB patients suffer from skin fragility starting with blister formation and evolving into chronic wounds, inflammation and skin fibrosis, with a high risk of developing aggressive skin carcinomas. Restricted therapeutic options are limited by the lack of in vitro models of defective wound healing in RDEB patients. Results: In order to explore a more efficient, non-invasive in vitro model for RDEB studies, we obtained patient fibroblasts derived from discarded dressings) and examined their phenotypic features compared with fibroblasts derived from non-injured skin of RDEB and healthy-donor skin biopsies. Our results demonstrate that fibroblasts derived from RDEB chronic wounds (RDEB-CW) displayed characteristics of senescent cells, increased myofibroblast differentiation, and augmented levels of TGF-β1 signaling components compared to fibroblasts derived from RDEB acute wounds and unaffected RDEB skin as well as skin from healthy-donors. Furthermore, RDEB-CW fibroblasts exhibited an increased pattern of inflammatory cytokine secretion (IL-1β and IL-6) when compared with RDEB and control fibroblasts. Interestingly, these aberrant patterns were found specifically in RDEB-CW fibroblasts independent of the culturing method, since fibroblasts obtained from dressing of acute wounds displayed a phenotype more similar to fibroblasts obtained from RDEB normal skin biopsies. Conclusions: Our results show that in vitro cultured RDEB-CW fibroblasts maintain distinctive cellular and molecular characteristics resembling the inflammatory and fibrotic microenvironment observed in RDEB patients' chronic wounds. This work describes a novel, non-invasive and painless strategy to obtain human fibroblasts chronically subjected to an inflammatory and fibrotic environment, supporting their use as an accessible model for in vitro studies of RDEB wound healing pathogenesis. As such, this approach is well suited to testing new therapeutic strategies under controlled laboratory conditions. [ABSTRACT FROM AUTHOR]

Abstract Background Recessive dystrophic epidermolysis bullosa (RDEB) is a rare, devastating blistering genodermatosis caused by mutations in the COL7A1 gene, which encodes for type VII collagen and is necessary for dermal-epidermal adhesion and integrity. Disease manifestations include severe and debilitating wounds, aggressive squamous cell carcinomas, and premature death; however, there are currently no approved therapies. This Phase 1/2a, open-label study evaluated the long-term efficacy and safety of gene-corrected autologous keratinocyte grafts (EB-101) for chronic RDEB wounds. Methods Autologous keratinocytes were harvested from participants with severe RDEB, transduced with a retrovirus containing the full-length COL7A1 gene, and grown into 5 × 7 cm (35 cm2) sheets. Gene-corrected keratinocyte sheets were then transplanted onto chronic RDEB wounds present for ≥ 12 weeks. Results Seven adult participants with severe RDEB were grafted with six sheets each (42 total sheets) onto wounds and followed for a mean of 5.9 years (range 4–8 years). Long-term improvements in wound healing and symptoms were observed. At year five, 70% (21/30) of treated sites demonstrated ≥ 50% wound healing compared to baseline by investigator global assessment. No sites with ≥ 50% wound healing were painful or pruritic, compared to 67% (6/9) of sites with

Background: Anemia is a common complication of severe forms of epidermolysis bullosa (EB). To date, there are no guidelines outlining best clinical practices to manage anemia in the EB population. The objective of this manuscript is to present the first consensus guidelines for the diagnosis and management of anemia in EB. Results: Due to the lack of high-quality evidence, a consensus methodology was followed. An initial survey exploring patient preferences, concerns and symptoms related to anemia was sent to EB patients and their family members. A second survey was distributed to EB experts and focused on screening, diagnosis, monitoring and management of anemia in the different types of EB. Information from these surveys was collated and used by the panel to generate 26 consensus statements. Consensus statements were sent to healthcare providers that care for EB patients through EB-Clinet. Statements that received more than 70% approval (completely agree/agree) were adopted. Conclusions: The end result was a series of 6 recommendations which include 20 statements that will help guide management of anemia in EB patients. In patients with moderate to severe forms of EB, the minimum desirable level of Hb is 100 g/L. Treatment should be individualized. Dietary measures should be offered as part of management of anemia in all EB patients, oral iron supplementation should be used for mild anemia; while iron infusion is reserved for moderate to severe anemia, if Hb levels of > 80–100 g/L (8–10 g/dL) and symptomatic; and transfusion should be administered if Hb is < 80 g/L (8 g/dL) in adults and < 60 g/L (6 g/dL) in children. [ABSTRACT FROM AUTHOR]

Background: Recessive dystrophic epidermolysis bullosa (RDEB) is a rare, devastating blistering genodermatosis caused by mutations in the COL7A1 gene, which encodes for type VII collagen and is necessary for dermal-epidermal adhesion and integrity. Disease manifestations include severe and debilitating wounds, aggressive squamous cell carcinomas, and premature death; however, there are currently no approved therapies. This Phase 1/2a, open-label study evaluated the long-term efficacy and safety of gene-corrected autologous keratinocyte grafts (EB-101) for chronic RDEB wounds.Methods: Autologous keratinocytes were harvested from participants with severe RDEB, transduced with a retrovirus containing the full-length COL7A1 gene, and grown into 5 × 7 cm (35 cm2) sheets. Gene-corrected keratinocyte sheets were then transplanted onto chronic RDEB wounds present for ≥ 12 weeks.Results: Seven adult participants with severe RDEB were grafted with six sheets each (42 total sheets) onto wounds and followed for a mean of 5.9 years (range 4-8 years). Long-term improvements in wound healing and symptoms were observed. At year five, 70% (21/30) of treated sites demonstrated ≥ 50% wound healing compared to baseline by investigator global assessment. No sites with ≥ 50% wound healing were painful or pruritic, compared to 67% (6/9) of sites with < 50% wound healing (p < 0.001) at year five. Grafts were well-tolerated throughout long-term follow-up. No serious adverse events related to treatment were reported over a mean of 5.9 years of follow-up. No persistent systemic autoimmunity against type VII collagen or replication-competent retrovirus infections were identified, and no participants developed squamous cell carcinomas related to treatment during long-term follow-up.Conclusions: Treatment with EB-101 appears safe and efficacious, and produces long-term improvements in wound healing, pain, and itch for RDEB patients. Results from the Phase 3 randomized controlled trial are forthcoming.Trial Registration: ClinicalTrials.gov, NCT01263379. Registered December 15, 2010. https://clinicaltrials.gov/ct2/show/NCT01263379. [ABSTRACT FROM AUTHOR]

Recessive dystrophic epidermolysis bullosa (RDEB) is a hereditary blistering disorder characterized by skin fragility, chronic inflammation, malnutrition, and fibrosis. Metabolomics is an emerging investigative field that helps elucidate disease pathophysiology and identify biomarkers. However, previous metabolomic studies in RDEB are limited. To investigate the plasma metabolomic profiles in RDEB patients. We recruited 10 RDEB patients and 10 age-/gender-matched healthy controls. Peripheral blood samples were collected and plasma metabolomic profiling was performed by LC-MS/MS analysis. MS data processing and compound identification were executed by MS-DIAL. Enrichment analysis was performed by MetaboAnalyst 5.0. Metabolomic analyses demonstrated that most amino acid levels were downregulated in RDEB patients, and the extent of insufficiency correlated with clinical severity. Several metabolites were dysregulated in RDEB, including glutamine and glutamate metabolism, tryptophan-to-kynurenine ratio, phenylalanine-to-tyrosine ratio, and succinate accumulation. The study was limited by small case numbers and the unrepresentativeness of a single time-point blood sample. Our study demonstrated the altered metabolomic profiles in RDEB, reflecting the disease severity, the chronic inflammatory and malnourished status, while the fibrotic signatures were not evident. • RDEB is characterized by skin fragility, chronic inflammation, and fibrosis, while the metabolomic profile has not been determined. • Plasma metabolomics helps elucidate disease pathophysiology and correlate nutritional status with disease severity. • The metabolomic dysregulation in RDEB highlights the chronic inflammatory and malnutrition status. Several amino acids levels, including glutamine, correlate with disease severity, and highlight the potential of future glutamine supplementation in RDEB. [ABSTRACT FROM AUTHOR]

• Absent or mutant type VII collagen (C7) leads to disrupted proteostasis in dermal fibroblasts characterized by intracellular protein accumulation, inefficient secretion, and increased cellular stress, resulting in activation of TGFβ signaling. • ER-Golgi traffic and secretion of the extracellular matrix (ECM)-associated proteins tissue transglutaminase (TGM2), thrombospondin-1 (TSP1), and type XII collagen (C12) can associate with either C7 or type I collagen in dermal fibroblasts. • We show that C7 acts as a scaffold to load TANGO1 mediated COPII carriers by binding both TANGO1 and COPII cargo. • Our data suggest that some components of ECM co-assemble in the ER and are exported as a unit. Lack of type VII collagen (C7) disrupts cellular proteostasis yet the mechanism remains undescribed. By studying the relationship between C7 and the extracellular matrix (ECM)-associated proteins thrombospondin-1 (TSP1), type XII collagen (C12) and tissue transglutaminase (TGM2) in primary human dermal fibroblasts from multiple donors with or without the genetic disease recessive dystrophic epidermolysis bullosa (RDEB) (n=31), we demonstrate that secretion of each of these proteins is increased in the presence of C7. In dermal fibroblasts isolated from patients with RDEB, where C7 is absent or defective, association with the COPII outer coat protein SEC31 and ultimately secretion of each of these ECM-associated proteins is reduced and intracellular levels are increased. In RDEB fibroblasts, overall collagen secretion (as determined by the levels of hydroxyproline in the media) is unchanged while traffic from the ER to Golgi of TSP1, C12 and TGM2 occurs in a type I collagen (C1) dependent manner. In normal fibroblasts association of TSP1, C12 and TGM2 with the ER exit site transmembrane protein T ransport AN d G olgi O rganization- 1 (TANGO1) as determined by proximity ligation assays, requires C7. In the absence of wild-type C7, or when ECM-associated proteins are overexpressed, C1 proximity and intracellular levels increase resulting in elevated cellular stress responses and elevated TGFβ signaling. Collectively, these data demonstrate a role for C7 in loading COPII vesicle cargo and provides a mechanism for disrupted proteostasis, elevated cellular stress and increased TGFβ signaling in patients with RDEB. Furthermore, our data point to a threshold of cargo loading that can be exceeded with increased protein levels leading to pathological outcomes in otherwise normal cells. [ABSTRACT FROM AUTHOR]

• Severe fibrotic features in recessive dystrophic epidermolysis bullosa (RDEB) are favored by a pro-oxidant status and hyper-responsiveness to TGF-β of dermal fibroblasts. • Antioxidant treatment reducing intrinsic high levels of ROS reverses part of the pro-fibrotic and contractile phenotype. • Prolargin / PRELP arises as a novel regulator of skin homeostasis by reducing TGF-β-driven fibrotic cues and promoting dermo-epidermal adherence. Recessive dystrophic epidermolysis bullosa (RDEB) is a genetic extracellular matrix disease caused by deficiency in type VII collagen (Col VII). The disease manifests with devastating mucocutaneous fragility leading to progressive fibrosis and metastatic squamous cell carcinomas. Although Col VII abundance is considered the main predictor of symptom course, previous studies have revealed the existence of mutation-independent mechanisms that control disease progression. Here, to investigate and validate new molecular modifiers of wound healing and fibrosis in a natural human setting, and toward development of disease-modulating treatment of RDEB, we performed gene expression profiling of primary fibroblast from RDEB siblings with marked phenotypic variations, despite having equal COL7A1 genotype. Gene enrichment analysis suggested that severe RDEB was associated with enhanced response to TGF-β stimulus, oxidoreductase activity, and cell contraction. Consistently, we found an increased response to TGF-β, higher levels of basal and induced reactive oxygen species (ROS), and greater contractile ability in collagen lattices in RDEB fibroblasts (RDEBFs) from donors with severe RDEB vs mild RDEB. Treatment with antioxidants allowed a reduction of the pro-fibrotic and contractile phenotype. Importantly, our analyses revealed higher expression and deposition in skin of the relatively uncharacterized small leucine-rich extracellular proteoglycan PRELP/prolargin associated with milder RDEB manifestations. Mechanistic investigations showed that PRELP effectively attenuated fibroblasts' response to TGF-β1 stimulus and cell contractile capacity. Moreover, PRELP overexpression in RDEBFs enhanced RDEB keratinocyte attachment to fibroblast-derived extracellular matrix in the absence of Col VII. Our results highlight the clinical relevance of pro-oxidant status and hyper-responsiveness to TGF-β in RDEB severity and progression. Of note, our study also reveals PRELP as a novel and natural TGF-β antagonist with a likely dermo-epidermal pro-adhesive capacity. [ABSTRACT FROM AUTHOR]

Recessive dystrophic epidermolysis bullosa (RDEB) manifests with blistering and erosions of the skin and mucous membranes due to mutations in COL7A1. The repetitive wound healing processes lead to extensive cutaneous scarring. The scarring is driven by inflammatory processes, particularly the TGF‐β signaling pathways, resulting in excess synthesis and deposition of the extracellular matrix, especially collagen. There is currently no effective or specific treatment for RDEB. Losartan, an angiotensin II type 1 receptor antagonist, is an inhibitor of TGF‐β activity. Previous preclinical studies with hypomorphic Col7a1 mice recapitulating features of RDEB have suggested that losartan may improve the clinical features of RDEB. In this case series, we assessed the effects of losartan on the clinical and histopathologic features in seven patients with RDEB; three females and four males; aged 18.1 ± 9.1 years. The diagnosis was based on characteristic clinical features and the presence of biallelic loss‐of‐function mutations in COL7A1. Daily oral administration of losartan (0.7 mg/kg) for six weeks resulted in subjective improvement of the clinical features, as judged by the treating physicians and the patients, and the severity of the disease objectively improved based on Birmingham Epidermolysis Bullosa Severity (BEBS) score (30.1 ± 12.8 versus 23.3 ± 10.4, before and after treatment, p = 0.018), accompanied by improvement of quality of life, as determined by the EB‐QoL questionnaire (24.0 ± 8.1 versus 17.7 ± 5.5, p = 0.018). Histopathology of the selected lesions revealed after treatment increased number of mast cells, and enhanced microvasculature in the mid and lower dermis. The width of collagen bundles in dermis was suggested to be decreased in four samples and changed from dense to loose in appearance. In summary, this case series reports beneficial effects of losartan on RDEB as a potentially novel treatment. [ABSTRACT FROM AUTHOR]