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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.

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.

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]

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 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.

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]

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]

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.

• 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]

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]

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

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: 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]

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).

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]

A male infant had the very fragile skin and easily formed bullas by rubbing and scratching from his birth. He was diagnosed with severe recessive dystrophic epidermolysis bullosa (RDEB) due to the lack of type VII collagen by performing an immunofluorescence mapping method from a skin biopsy specimen of the patient’s bulla. We analyzed the skin microbiome using next-generation sequencer. The species from the patient’s skin revealed the dominance of Staphylococcus aureus (S. aureus) similar to the reports from Austria and Chile severe RDEB patients, and these results are same as the pattern isolated from the skin of atopic dermatitis (AD) patients with flares. The interaction of microbiome and skin microenvironment may be similar between RDEB and AD worldwide.

Abstract Background/objective Recessive dystrophic epidermolysis bullosa (RDEB) is a genetic collagen disorder characterized by skin fragility leading to blistering, wounds, and scarring. There are currently no approved curative therapies. The objective of this manuscript is to provide a comprehensive literature review of the disease burden caused by RDEB. Methods A systematic literature review was conducted in MEDLINE and Embase in accordance with PRISMA guidelines. Observational and interventional studies on the economic, clinical, or humanistic burden of RDEB were included. Results Sixty-five studies were included in the review. Patients had considerable wound burden, with 60% reporting wounds covering more than 30% of their body. Increases in pain and itch were seen with larger wound size. Chronic wounds were larger and more painful than recurrent wounds. Commonly reported symptoms and complications included lesions and blistering, anemia, nail dystrophy and loss, milia, infections, musculoskeletal contractures, strictures or stenoses, constipation, malnutrition/nutritional problems, pseudosyndactyly, ocular manifestations, and dental caries. Many patients underwent esophageal dilation (29–74%; median dilations, 2–6) and gastrostomy tube placement (8–58%). In the severely affected population, risk of squamous cell carcinoma (SCC) was 76% and mortality from SCC reached 84% by age 40. Patients with RDEB experienced worsened quality of life (QOL), decreased functioning and social activities, and increased pain and itch when compared to other EB subtypes, other skin diseases, and the general population. Families of patients reported experiencing high rates of burden including financial burden (50–54%) and negative impact on private life (79%). Direct medical costs were high, though reported in few studies; annual payer-borne total medical costs in Ireland were $84,534 and annual patient-borne medical costs in Korea were $7392. Estimated annual US costs for wound dressings ranged from $4000 to $245,000. Patients spent considerable time changing dressings: often daily (13–54% of patients) with up to three hours per change (15–40%). Conclusion Patients with RDEB and their families/caregivers experience significant economic, humanistic, and clinical burden. Further research is needed to better understand the costs of disease, how the burden of disease changes over the patient lifetime and to better characterize QOL impact, and how RDEB compares with other chronic, debilitating disorders.

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.

Les épidermolyses bulleuses dystrophiques récessives représentent un groupe de maladies génétiques, caractérisées par une fragilité cutanée et muqueuse, causées par des mutations dans le gène COL7A1. L'amylose AA constitue une complication rare de ces génodermatoses. Deux patients, porteurs d'une épidermolyse bulleuse dystrophique récessive, généralisée sévère dans le premier cas et généralisée intermédiaire dans le deuxième cas, ont développé à l'âge de 38 et 28 ans, respectivement, un syndrome néphrotique. Le diagnostic d'amylose rénale secondaire était confirmé par une biopsie rénale dans le premier cas et des glandes salivaires dans le deuxième cas. Le décès est survenu deux mois après dans les deux cas. L'amylose AA au cours des épidermolyses bulleuses dystrophiques récessives est souvent révélée par une atteinte rénale caractérisée par un syndrome néphrotique et une insuffisance rénale d'aggravation rapide. Le pronostic est sombre au vu de la fragilité du terrain et l'absence d'un traitement étiologique. Recessive dystrophic epidermolysis bullosa is a rare genetic condition characterized by fragile skin and mucous membrane, caused by mutations in the COL7A1 gene. AA amyloidosis is a rare complication of these genodermatosis. Two patients with recessive dystrophic epidermolysis bullosa, generalized severe in the first case and generalized intermediate in the second case, developed at the age of 38 and 28, respectively, nephrotic syndrome. The diagnosis of secondary renal amyloidosis was confirmed by renal biopsy in the first case and by minor salivary gland biopsy in the second case. Death occurred 2 months after diagnosis in both cases. Renal involvement is quite common in AA amyloidosis in patients with recessive dystrophic epidermolysis bullosa. Nephrotic syndrome and rapid decline in renal function renal are characteristic features. The prognosis is poor due to underlying conditions and the lack of an etiological treatment. [ABSTRACT FROM AUTHOR]

The treatment of recessive dystrophic epidermolysis bullosa (RDEB) remains challenging. Elevated IgE levels have previously been reported in several RDEB patients. In this prospective, single‐centre, open intervention study, elevated IgE levels were seen in 11 out of 12 patients with intense pruritus, and the patients with elevated IgE levels received anti‐IgE therapy every 4 weeks for at least three cycles. Compared with the baseline, 10 patients with RDEB had good clinical outcomes with enhanced wound healing, a reduction in Birmingham (epidermolysis bullosa) EB severity score by 15%, a reduction in affected body surface area by 23.3%, amelioration of skin inflammation, and an increase in type VII collagen deposition by 13.1‐fold. All the patients had a good tolerance to anti‐IgE therapy. Furthermore, patients with higher IgE levels tended to have higher disease severity and more favorable clinical outcomes. Our report also suggested the potential role of IgE in the pathogenesis of inflammatory conditions associated with RDEB. (ChiCTR1900021437). [ABSTRACT FROM AUTHOR]

Recessive dystrophic epidermolysis bullosa (RDEB) is a genodermatosis that leads to skin fragility and chronic wound formation. Patients with RDEB are at risk for cutaneous squamous cell carcinoma (SCC) which is a major cause of morbidity and mortality in these patients. No standard of care exists for the treatment of SCC in this patient population and therapy is based on anecdotal reports and expert opinion. We report a 32-year-old man with RDEB with previously localized SCC who later developed metastatic SCC. He was started on cemiplimab (an immune checkpoint inhibitor) 350 mg IV every 3 weeks. An objective radiological response was noted within 3 cycles. On 14 months follow-up, there was a durable response to treatment clinically and on imaging, without immune-related adverse events. To our knowledge, this is the first case report describing safe administration of immune checkpoint inhibitors in a patient with RDEB with objective and durable response of metastatic SCC. Larger case series and controlled clinical trials are needed to further investigate these medications in the RDEB population, given their high burden of aggressive and often lethal SCC.

Recessive dystrophic epidermolysis bullosa (RDEB) is a severely debilitating disorder caused by pathogenic variants in COL7A1 and is characterized by extreme skin fragility, chronic inflammation, and fibrosis. A majority of patients with RDEB develop squamous cell carcinoma, a highly aggressive skin cancer with limited treatment options currently available. In this study, we utilized an approach leveraging whole-genome sequencing and RNA sequencing across 3 different tissues in a single patient with RDEB to gain insight into possible mechanisms of RDEB-associated squamous cell carcinoma progression and to identify potential therapeutic options. As a result, we identified PLK-1 as a possible candidate for targeted therapy and discovered microsatellite instability and accelerated aging as factors potentially contributing to the aggressive nature and early onset of RDEB squamous cell carcinoma. By integrating multitissue genomic and transcriptomic analyses in a single patient, we demonstrate the promise of bridging the gap between genomic research and clinical applications for developing tailored therapies for patients with rare genetic disorders such as RDEB., (Published by Elsevier Inc.)

Recessive dystrophic epidermolysis bullosa (RDEB) is a rare and severe genetic skin disease responsible for blistering of the skin and mucosa after minor trauma. RDEB is caused by a wide variety of variants in COL7A1 encoding type VII Collagen, the major component of anchoring fibrils that form key attachment structures for dermal-epidermal adherence. In this study, we achieved highly efficient COL7A1 editing in primary RDEB keratinocytes and fibroblasts from 2 patients homozygous for the c.6508C>T (p.Gln2170∗) variant through CRISPR/Cas9-mediated homology-directed repair. Three guide RNAs targeting the c.6508C>T variant or harboring sequences were delivered together with high-fidelity Cas9 as a ribonucleoprotein complex. Among them, one achieved 73% cleavage activity in primary RDEB keratinocytes and RDEB fibroblasts. Then, we treated RDEB keratinocytes and RDEB fibroblasts with this specific ribonucleoprotein complex and the corresponding donor template delivered as single-stranded oligodeoxynucleotide and achieved up to 58% of genetic correction as well as type VII Collagen rescue. Finally, grafting of corrected 3-dimensional skin onto nude mice induced re-expression and normal localization of type VII Collagen as well as anchoring fibril formation at the dermal-epidermal junction 5 and 10 weeks after grafting. With this promising nonviral approach, we achieved therapeutically relevant specific gene editing that could be applicable to all variants in exon 80 of COL7A1 in primary RDEB cells., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

Introduction: Epidermolysis bullosa (EB) is a rare genetic skin disorder inherited either in autosomal recessive (AR) or autosomal dominant (AD) manner and characterized by blistering of the skin and mucous membranes. According to a subtype of EB, the oral manifestations and dental involvement vary in frequency and in severity. The most severe dental problems occur in patients with junctional epidermolysis bullosa (JEB) and severe generalized dystrophic epidermolysis bullosa (RDEB) and involve enamel erosion and development of blisters followed by painful oral wounds. Oral mucosa lesions decrease patients' quality of life and may contribute to difficulties in nutrition leading to cachexia. Aim: Assessment of efficacy of gentamicin 0.3% solution in the healing and preventing of oral erosions in patients with RDEB and evaluating its impact on the expression of type VII collagen. Material and methods: The study included four female patients with RDEB, aged 16-42 who show different mutations in the COL7A1 gene and were administered the mouth rinse two times daily with a solution of 0.3% gentamycin for 4 consecutive weeks. Prior to and at the end of the study, the samples from oral mucosa were collected to estimate the expression of type VII collagen by immunofluorescence test. Results: The clinical improvement of oral wounds healing and reduced number of new blisters and mucous membrane soreness as well as partial re-expression of type VII collagen was observed in all studied patients. Conclusions: Topical gentamicin therapy of oral cavity in RDEB patients resulted in clinical improvement of mucosal lesions and re-expression of collagen type VII. [ABSTRACT FROM AUTHOR]

• Patients with RDEB lack functional Type VII collagen (C7). • The Inversa subtype (RDEB-I) affects body areas of higher temperature. • The structural and functional abnormalities of RDEB-I C7 are temperature-dependent. • The abnormal RDEB-I fibroblast phenotype is correctable at lower temperatures. Patients with recessive dystrophic epidermolysis bullosa (RDEB) lack functional type VII collagen (C7) leading to skin fragility, bullae, and erosive wounds. RDEB-Inversa (RDEB-I), a subset of RDEB, is characterized by lesions localized to body areas with higher skin temperatures such as flexures and skin folds. We aimed to determine if C7 derived from RDEB-I mutations had structural and functional aberrancies that were temperature sensitive and could be reversed by lowering the temperature. In this study, we generated 12 substitution mutations associated with RDEB-I via site-directed mutagenesis and purified recombinant C7 protein. These C7 mutants were evaluated for structural parameters (trimer formation and protease sensitivity) and the ability to promote keratinocyte migration at 37 °C (the temperature of skin folds) and 30 °C (the maximum skin temperature of arms and legs). Fibroblasts derived from RDEB-I patients were evaluated for C7 secretion and cellular migration at both temperatures. C7s from RDEB-I mutations exhibited decreased thermal stability, increased sensitivity to protease digestion, diminished formation of collagen trimers, and reduced ability to promote keratinocyte migration compared with wild-type C7. In addition, fibroblasts derived from RDEB-I patients demonstrated intracellular accumulation of C7 and abnormal cell migration at 37 °C. All of these aberrancies were corrected by reducing the temperature to 30 °C. C7s generated from severe-RDEB mutations (non-Inversa) did not display temperature-dependent perturbations. These data demonstrate that RDEB-I mutations generate C7 aberrancies that are temperature dependent. This may explain why RDEB-I patients develop clinical lesions in areas where their skin is considerably warmer. [ABSTRACT FROM AUTHOR]

Background: A spectrum of skin disease severity exists in patients with recessive dystrophic epidermolysis bullosa (RDEB).Objective: To characterize the patient-reported outcomes and quality of life (QOL) in patients with RDEB.Methods: A cross-sectional study of patients with RDEB surveyed through the global EBCare Registry. Patient-reported outcomes included skin disease severity, wound characteristics, pain, itch, extracutaneous symptoms, and medications. QOL was measured by using the validated Quality of Life in Epidermolysis Bullosa instrument.Results: A total of 85 patients with RDEB reported 1226 wounds (937 recurrent wounds and 289 chronic open wounds). Overall skin disease severity was self-reported as mild (26%; 22/83), moderate (48%; 40/83), or severe (25%; 21/83). Worsening skin disease severity was significantly associated with larger wounds, increased opiate use, anemia, gastrostomy tube use, infections, osteoporosis, and squamous cell carcinoma. Larger wound size was associated with worse quality of life scores.Limitations: All data were self-reported from an online epidermolysis bullosa patient registry.Conclusions: This study shows a significant correlation between larger wound size with worsening skin disease severity and quality of life in participants with RDEB. Worsening skin disease severity significantly correlated with key clinical manifestations. These results show that patients with RDEB are able to self-report their skin disease severity and wounds. [ABSTRACT FROM AUTHOR]

Recessive dystrophic epidermolysis bullosa (RDEB) (Hallopeau Siemens) is one of the most severe forms of epidermolysis bullosa (EB) with generalized vesiculation over the skin and mucous membrane resulting in extensive scarring with exuberant granulation tissue. Because of widespread erosions, patients are prone to secondary infection. We are reporting a 10-year-old male child having RDEB who presented with a nonhealing ulcer with verrucous growth over bilateral knees for 2 years which was considered as part of the disease by many dermatologists and was later diagnosed to be superadded chromoblastomycosis based on histopathology. We are highlighting this case to increase awareness among dermatologists regarding the occurrence of superadded deep fungal infections like chromoblastomycosis in patients of RDEB which is usually missed or misdiagnosed as part of the disease.

Dermal fibroblasts are the most accessible cells in the skin that have gained significant attention in cell therapy. Applying dermal fibroblasts' regenerative capacity can introduce new patterns to develop cell‐based therapies to treat skin disorders. Dermal fibroblasts originate from mesenchymal cells and are located within the dermis. These cells are mainly responsible for synthesizing glycosaminoglycans, collagens, and components of extracellular matrix supporting skin's structural integrity. Preclinical studies suggested that allogeneic and autologous dermal fibroblasts provide widespread and beneficial applications for wound healing, burn ulcers, and inherited skin disorders. In this regard, generating induced pluripotent stem cells (iPSCs) from fibroblasts and gene‐edited fibroblasts are promising approaches for treating skin disorders. Here, we aimed to review literature about ongoing and completed clinical trials that applied fibroblasts and bioengineered fibroblasts as therapeutic agents for various skin disorders. This review explores cell therapy protocols from the earliest phase of allogeneic and autologous fibroblasts development in different benches to translating them into bedside‐level treatment for skin disorders, particularly recessive dystrophic epidermolysis bullosa. [ABSTRACT FROM AUTHOR]

Epidermolysis bullosa (EB) is an umbrella term for a group of rare inherited skin disorders characterised by mucocutaneous fragility. Patients suffer from blisters and chronic wounds that arise spontaneously or following minor mechanical trauma, often resulting in inflammation, scarring and fibrosis due to poor healing. The recessive form of dystrophic EB (RDEB) has a particularly severe phenotype and is caused by mutations in the COL7A1 gene, encoding the collagen VII protein, which is responsible for adhering the epidermis and dermis together. One of the most feared and devastating complications of RDEB is the development of an aggressive form of cutaneous squamous cell carcinoma (cSCC), which is the main cause of mortality in this patient group. However, pathological drivers behind the development and progression of RDEB-associated cSCC (RDEB-cSCC) remain somewhat of an enigma, and the evidence to date points towards a complex process. Currently, there is no cure for RDEB-cSCC, and treatments primarily focus on prevention, symptom management and support. Therefore, there is an urgent need for a comprehensive understanding of this cancer's pathogenesis, with the aim of facilitating the discovery of drug targets. This review explores the current knowledge of RDEB-cSCC, emphasising the important role of the immune system, genetics, fibrosis, and the tumour-promoting microenvironment, all ultimately intricately interconnected. [ABSTRACT FROM AUTHOR]

Some bone lesions are reported to mimic bone metastasis on imaging tests. Herein, we report a case of a 55-year-old Japanese man who presented with a skin tumor on the left lower extremity. He also had a history of recurrent generalized cutaneous blister and erosion formation since childhood. His skin lesions were diagnosed as cutaneous squamous cell carcinoma complicated by recessive dystrophic epidermolysis bullosa. Magnetic resonance imaging of the left lower extremity detected multiple focal bone lesions mimicking bone metastases in the left femur and tibia. However, bone biopsy revealed that the bone lesions were osteonecrosis without tumor cells. We suggest that cancer-induced osteonecrosis should be included in the differential diagnosis of bone lesions suspected of being metastases on magnetic resonance imaging.

Aim. To evaluate the clinical efficacy of modern atraumatic non-adherent wound dressings in patients with congenital epidermolysis bullosa. Materials and methods. The study involved 9 patients diagnosed with congenital epidermolysis bullosa (EB), including 7 women and 2 men aged 21–50 years. All the patients underwent immunofluorescent antigenic mapping of skin biopsies to confirm the clinical diagnosis. External therapy using modern atraumatic non-adherent wound dressings was performed in all the patients. The evaluation of the clinical efficacy of the applied therapy was carried out on the 14th and 30th day in accordance with the following criteria: complete healing of erosions or ulcers; significant improvement (reduction of erosions/ulceration by at least 75 % compared with the baseline data, reduction of exudate, the presence of granulations, reduction of inflammation signs, reduction of pain); improvement (reduction of erosions/ulceration area by less than 75 %, but more than 25 % compared with the baseline data, reduction of exudate, presence of granulations, reduction of inflammation signs, reduction of pain); without change (reduction of erosions/ulceration by less than 25 % or no change compared with the baseline data, a slight decrease in the amount of exudate, no granulations, a slight decrease in inflammation signs, a slight reduction of pain); deterioration (increase in the area of erosions/ulceration, increase in the amount of exudate, the level of inflammation and subjective estimation either increases or remains the same). Results. On the 14th day, 22 out of 58 (37.9 %) erosions were epithelized. The area of 15 erosions was reduced by more than 75 %. The area of 12 erosions (20.6 %) was reduced by more than 25 %, but less than 75 %. The area of 7 (12.25 %) erosions decreased by less than 25 %. The area of 2 erosions in patients with severe generalised recessive dystrophic epidermolysis bullosa (RDEB) increased (3.45 %). Out of 36 erosions that had not been epithelized by the 14th day, 20 (55.5 %) achieved complete healing by the 30th day. The dimensions and characteristics of 5 (13.8 %) nonhealing erosive-ulcerative defects had remained unchanged by the 30th day. The share of reduction in the area of these defects did not exceed 30 %. Conclusion. The obtained results demonstrate the clinical efficacy of external therapy using modern atraumatic nonadherent wound dressings. The dynamic observation of erosive-ulcerative defects, regular documentation of changes in the parameters of erosive and ulcerative defects allows the development of standardised approaches of efficient external therapy in such conditions, including the selection of non-adherent dressings. Objective assessment of the dynamics of erosive-ulcerative skin defects contributes to the development of individualized plans for treating EB patients.

A male infant had the very fragile skin and easily formed bullas by rubbing and scratching from his birth. He was diagnosed with severe recessive dystrophic epidermolysis bullosa (RDEB) due to the lack of type VII collagen by performing an immunofluorescence mapping method from a skin biopsy specimen of the patient's bulla. We analyzed the skin microbiome using next-generation sequencer. The species from the patient's skin revealed the dominance of Staphylococcus aureus (S. aureus) similar to the reports from Austria and Chile severe RDEB patients, and these results are same as the pattern isolated from the skin of atopic dermatitis (AD) patients with flares. The interaction of microbiome and skin microenvironment may be similar between RDEB and AD worldwide. [ABSTRACT FROM AUTHOR]