Haploinsufficiency for one COL3A1 allele of type III procollagen results in a phenotype similar to the vascular form of Ehlers-Danlos syndrome, Ehlers-Danlos syndrome type IV

Is Exon Skipping a Viable Therapeutic Approach for Vascular Ehlers-Danlos Syndrome with Mutations in COL3A1 Exon 10 or 15?

Vascular Ehlers-Danlos syndrome or Ehlers-Danlos syndrome type IV (vEDS) is a connective tissue disorder characterised by skin hyperextensibility, joint hypermobility and fatal vascular rupture caused by COL3A1 mutations that affect collagen III expression, homo-trimer assembly and secretion. Along with collagens I, II, V and XI, collagen III plays an important role in the extracellular matrix, particularly in the inner organs. To date, only symptomatic treatment for vEDS patients is available. Fibroblasts derived from vEDS patients carrying dominant negative and/or haploinsufficiency mutations in COL3A1 deposit reduced collagen III in the extracellular matrix. This study explored the potential of an antisense oligonucleotide (ASO)-mediated splice modulating strategy to bypass disease-causing COL3A1 mutations reported in the in-frame exons 10 and 15. Antisense oligonucleotides designed to redirect COL3A1 pre-mRNA processing and excise exons 10 or 15 were transfected into dermal fibroblasts derived from vEDS patients and a healthy control subject. Efficient exon 10 or 15 excision from the mature COL3A1 mRNA was achieved and intracellular collagen III expression was increased after treatment with ASOs; however, collagen III deposition into the extracellular matrix was reduced in patient cells. The region encoded by exon 10 includes a glycosylation site, and exon 15 encodes hydroxyproline and hydroxylysine-containing triplet repeats, predicted to be crucial for collagen III assembly. These results emphasize the importance of post-translational modification for collagen III homo-trimer assembly. In conclusion, while efficient skipping of target COL3A1 exons was achieved, the induced collagen III isoforms generated showed defects in extracellular matrix formation. While therapeutic ASO-mediated exon skipping is not indicated for the patients in this study, the observations are restricted to exons 10 and 15 and may not be applicable to other collagen III in-frame exons.

Bioengineered vascular grafts with a pathogenic TGFBR1 variant model aneurysm formation in vivo and reveal underlying collagen defects

Thoracic aortic aneurysm (TAA) is a life-threatening vascular disease frequently associated with underlying genetic causes. An inadequate understanding of human TAA pathogenesis highlights the need for better disease models. Here, we established a functional human TAA model in an animal host by combining human induced pluripotent stem cells (hiPSCs), bioengineered vascular grafts (BVGs), and gene editing. We generated BVGs from isogenic control hiPSC-derived vascular smooth muscle cells (SMCs) and mutant SMCs gene-edited to carry a Loeys-Dietz syndrome (LDS)-associated pathogenic variant (TGFBR1A230T). We also generated hiPSC-derived BVGs using cells from a patient with LDS (PatientA230T/+) and using genetically corrected cells (Patient+/+). Control and experimental BVGs were then implanted into the common carotid arteries of nude rats. The TGFBR1A230T variant led to impaired mechanical properties of BVGs, resulting in lower burst pressure and suture retention strength. BVGs carrying the variant dilated over time in vivo, resembling human TAA formation. Spatial transcriptomics profiling revealed defective expression of extracellular matrix (ECM) formation genes in PatientA230T/+ BVGs compared with Patient+/+ BVGs. Histological analysis and protein assays validated quantitative and qualitative ECM defects in PatientA230T/+ BVGs and patient tissue, including decreased collagen hydroxylation. SMC organization was also impaired in PatientA230T/+ BVGs as confirmed by vascular contraction testing. Silencing of collagen-modifying enzymes with small interfering RNAs reduced collagen proline hydroxylation in SMC-derived tissue constructs. These studies demonstrated the utility of BVGs to model human TAA formation in an animal host and highlighted the role of reduced collagen modifying enzyme activity in human TAA formation.

Vertebral Tortuosity Is Associated With Increased Rate of Cardiovascular Events in Vascular Ehlers-Danlos Syndrome

Background Arterial tortuosity is associated with adverse events in Marfan and Loeys-Dietz syndromes but remains understudied in Vascular Ehlers-Danlos syndrome. Methods and Results Subjects with a pathogenic COL3A1 variant diagnosed at age <50 years were included from 2 institutions and the GenTAC Registry (National Registry of Genetically Triggered Thoracic Aortic Aneurysms and Cardiovascular Conditions). Height-adjusted vertebral artery tortuosity index (VTI-h) using magnetic resonance or computed tomography angiography was calculated. Associations between VTI-h and outcomes of (1) cardiovascular events (arterial dissection/rupture, aneurysm requiring intervention, stroke), or (2) hollow organ collapse/rupture at age <50 years were evaluated using receiver operator curve analysis (using outcome by age 30 years) and mixed-effects Poisson regression for incidence rate ratios. Of 65 subjects (54% male), median VTI-h was 12 (interquartile range, 8-16). Variants were missense in 46%, splice site in 31%, and null/gene deletion in 14%. Thirty-two subjects (49%) had 59 events, including 28 dissections, 5 arterial ruptures, 4 aneurysms requiring intervention, 4 strokes, 11 hollow organ ruptures, and 7 pneumothoraces. Receiver operator curve analysis suggested optimal discrimination at VTI-h ≥15.5 for cardiovascular events (sensitivity 70%, specificity 76%) and no association with noncardiovascular events (area under the curve, 0.49 [95% CI, 0.22-0.78]). By multivariable analysis, older age was associated with increased cardiovascular event rate while VTI-h ≥15.5 was not (incidence rate ratios, 1.79 [95% CI, 0.76-4.24], P=0.185). However, VTI-h ≥15.5 was associated with events among those with high-risk variants <40 years (incidence rate ratios, 4.14 [95% CI, 1.13-15.10], P=0.032), suggesting effect modification by genotype and age. Conclusions Increased arterial tortuosity is associated with a higher incidence rate of cardiovascular events in Vascular Ehlers-Danlos syndrome. Vertebral tortuosity index may be a useful biomarker for prognosis when evaluated in conjunction with genotype and age.

Genetic Basis, New Diagnostic Approaches, and Updated Therapeutic Strategies of the Syndromic Aortic Diseases: Marfan, Loeys-Dietz, and Vascular Ehlers-Danlos Syndrome

Syndromic aortic diseases (SADs) encompass various pathological manifestations affecting the aorta caused by known genetic factors, such as aneurysms, dissections, and ruptures. However, the genetic mutation underlying aortic pathology also gives rise to clinical manifestations affecting other vessels and systems. As a consequence, the main syndromes currently identified as Marfan, Loeys-Dietz, and vascular Ehlers-Danlos are characterized by a complex clinical picture. In this contribution, we provide an overview of the genetic mutations currently identified in order to have a better understanding of the pathogenic mechanisms. Moreover, an update is presented on the basis of the most recent diagnostic criteria, which enable an early diagnosis. Finally, therapeutic strategies are proposed with the goal of improving the rates of patient survival and the quality of life of those affected by these SADs.

Patient-derived extracellular matrix demonstrates role of COL3A1 in blood vessel mechanics

Vascular Ehlers-Danlos Syndrome (vEDS) is a rare autosomal dominant disease caused by mutations in the COL3A1 gene, which renders patients susceptible to aneurysm and arterial dissection and rupture. To determine the role of COL3A1 variants in the biochemical and biophysical properties of human arterial ECM, we developed a method for synthesizing ECM directly from vEDS donor fibroblasts. We found that the protein content of the ECM generated from vEDS donor fibroblasts differed significantly from ECM from healthy donors, including upregulation of collagen subtypes and other proteins related to ECM structural integrity. We further found that ECM generated from a donor with a glycine substitution mutation was characterized by increased glycosaminoglycan content and unique viscoelastic mechanical properties, including increased time constant for stress relaxation, resulting in a decrease in migratory speed of human aortic endothelial cells when seeded on the ECM. Collectively, these results demonstrate that vEDS patient-derived fibroblasts harboring COL3A1 mutations synthesize ECM that differs in composition, structure, and mechanical properties from healthy donors. These results further suggest that ECM mechanical properties could serve as a prognostic indicator for patients with vEDS, and the insights provided by the approach demonstrate the broader utility of cell-derived ECM in disease modeling. STATEMENT OF SIGNIFICANCE: The role of collagen III ECM mechanics remains unclear, despite reported roles in diseases including fibrosis and cancer. Here, we generate fibrous, collagen-rich ECM from primary donor cells from patients with vascular Ehlers-Danlos syndrome (vEDS), a disease caused by mutations in the gene that encodes collagen III. We observe that ECM grown from vEDS patients is characterized by unique mechanical signatures, including altered viscoelastic properties. By quantifying the structural, biochemical, and mechanical properties of patient-derived ECM, we identify potential drug targets for vEDS, while defining a role for collagen III in ECM mechanics more broadly. Furthermore, the structure/function relationships of collagen III in ECM assembly and mechanics will inform the design of substrates for tissue engineering and regenerative medicine.

Building a Scaffold for Arteriovenous Fistula Maturation: Unravelling the Role of the Extracellular Matrix

Vascular access is the lifeline for patients receiving haemodialysis as kidney replacement therapy. As a surgically created arteriovenous fistula (AVF) provides a high-flow conduit suitable for cannulation, it remains the vascular access of choice. In order to use an AVF successfully, the luminal diameter and the vessel wall of the venous outflow tract have to increase. This process is referred to as AVF maturation. AVF non-maturation is an important limitation of AVFs that contributes to their poor primary patency rates. To date, there is no clear overview of the overall role of the extracellular matrix (ECM) in AVF maturation. The ECM is essential for vascular functioning, as it provides structural and mechanical strength and communicates with vascular cells to regulate their differentiation and proliferation. Thus, the ECM is involved in multiple processes that regulate AVF maturation, and it is essential to study its anatomy and vascular response to AVF surgery to define therapeutic targets to improve AVF maturation. In this review, we discuss the composition of both the arterial and venous ECM and its incorporation in the three vessel layers: the tunica intima, media, and adventitia. Furthermore, we examine the effect of chronic kidney failure on the vasculature, the timing of ECM remodelling post-AVF surgery, and current ECM interventions to improve AVF maturation. Lastly, the suitability of ECM interventions as a therapeutic target for AVF maturation will be discussed.

Open repair of abdominal aortic aneurysms in patients with vascular Ehlers-Danlos syndrome

Vascular Ehlers-Danlos syndrome (VEDS) is rare, affecting an estimated 1 per 50,000 individuals, and is associated with abdominal aortic aneurysms (AAAs), among other arteriopathies. We present three patients with genetically confirmed VEDS who underwent successful open AAA surgical repair and demonstrate that elective open AAA repair with careful tissue manipulation is safe and feasible for patients with VEDS. These cases also demonstrate that the VEDS genotype is associated with the aortic tissue quality (genotype-surgical phenotype correlation), with the most friable tissue encountered in the patient with a large amino acid substitution and the least friable tissue in the patient with a null (haploinsufficiency) variant.

Endovascular repair of a common iliac artery aneurysm with an iliac branch device in a patient with vascular Ehlers-Danlos syndrome due to a null COL3A1 variant

Endovascular repair is avoided in patients with connective tissues disorders due to concerns for stent graft migration and endoleaks. We describe a successful endovascular repair of a common iliac artery aneurysm with a bifurcated aortoiliac stent graft and iliac branch endoprosthesis in a patient with Vascular Ehlers-Danlos syndrome (VEDS) due to a null COL3A1 variant. This case demonstrates that the VEDS genotype is associated with tissue integrity, specifically, individuals with VEDS due to null/haploinsufficiency variants, and adds to our understanding of endovascular repair in this population.

TGFβ signaling pathways in human health and disease

Transforming growth factor beta (TGFβ) is named for the function it was originally discovered to perform-transformation of normal cells into aggressively growing malignant cells. It became apparent after more than 30 years of research, however, that TGFβ is a multifaceted molecule with a myriad of different activities. TGFβs are widely expressed with almost every cell in the human body producing one or another TGFβ family member and expressing its receptors. Importantly, specific effects of this growth factor family differ in different cell types and under different physiologic and pathologic conditions. One of the more important and critical TGFβ activities is the regulation of cell fate, especially in the vasculature, that will be the focus of this review.

Splenic artery pathology presentation, operative interventions, and outcomes in 88 patients with Vascular Ehlers Danlos Syndrome

BACKGROUND

Vascular Ehlers-Danlos Syndrome (VEDS) is rare and associated with arteriopathies. The aim of this study is to investigate the presentation, operative interventions, and outcomes of splenic arterial pathology in a population of more than 1,500 individuals with genetically confirmed VEDS due to pathogenic COL3A1 variants.

METHODS

Cross-sectional analysis of 1,547 individuals was performed. The data were assembled by harmonizing data from three overlapping cohorts with genetically confirmed VEDS: the VEDS Collaborative Natural History Study (N=242), a single center cohort (N=75), and the UW Collagen Diagnostic Lab cohort (N=1,231). Duplicates were identified and removed. Patients were selected for analysis if they had splenic artery aneurysm (SAA), pseudoaneurysm, dissection, thrombosis, or rupture. Demographics, COL3A1 variants, interventions, and outcomes were analyzed. Comparisons by splenic artery rupture were made.

RESULTS

A total of 88 patients presented between 1992 and 2021 with splenic artery pathology (5.7% of the cohort, Mean age at diagnosis 37+11.1 years, 50% male). One third were diagnosed with VEDS prior to the splenic artery pathology diagnosis and 17% were diagnosed post-mortem. Most had a positive family history (61%). Most had COL3A1 variants associated with minimal normal collagen production (71.589.7%). Median follow up was 8.5 (IQR 0.9-14.7) years. Initial presentation was rupture in 47% of the cases. Splenic artery rupture overall was 51% (N=45) including 4 cases of splenic rupture. There were no major differences in VEDS related manifestations or COL3A1 variant type by rupture status. SAA was noted in 39% of the cases. Only 12 patients had splenic artery diameter documented in 12 cases with a median diameter of 12 (IQR 10.3-19.3) mm. A total of 34 (38.6%) patients underwent 40 splenic arterial interventions: 21 open surgical, 18 embolization, and 1 unknown procedure. More than one splenic artery intervention was performed in 5 (14.7%) cases. Open repair complications included arteriovenous fistula (n=1), intestinal or pancreatic injury (1 each), and four intraoperative deaths. There were no deaths or access site complications related to splenic artery embolization. Four (23.5%) developed a new SAA in the remaining splenic artery post embolization. All-cause mortality was 35% (n=31) including 22 related to a ruptured splenic artery.

CONCLUSIONS

Splenic arteriopathy in VEDS is associated with variants that affect the structure and secretion of type III collagen and frequently present with rupture. Rupture and open repair are associated with high morbidity and mortality while embolization is associated with favorable outcomes. Suggest repair considerations at SAA diameter of 15 mm. Long term follow up is indicated as secondary splenic arteriopathy can occur.

Identification of COL4A4 variants in Chinese patients with familial hematuria

Background: Benign familial hematuria and Alport syndrome are common causes of familial hematuria among children and young adults, which are attributable to variants in the collagen type IV alpha chain genes, COL4A3, COL4A4, or COL4A5. The study was conducted to identify the underlying genetic causes in patients with familial hematuria. Methods: Two unrelated Han-Chinese pedigrees with familial hematuria were recruited for this study. Whole exome sequencing was combined with in silico analysis to identify potential genetic variants, followed by variant confirmation by Sanger sequencing. Reverse transcription, PCR, and Sanger sequencing were performed to evaluate the effect of the detected splicing variant on mRNA splicing. Results: A novel heterozygous splicing c.595-1G>A variant and a known heterozygous c.1715G>C variant in the collagen type IV alpha 4 chain gene (COL4A4) were identified and confirmed in patients of pedigree 1 and pedigree 2, respectively. Complementary DNA analysis indicated this splicing variant could abolish the canonical splice acceptor site and cause a single nucleotide deletion of exon 10, which was predicted to produce a truncated protein. Conclusions: The two COL4A4 variants, c.595-1G>A variant and c.1715G>C (p.Gly572Ala) variant, were identified as the genetic etiologies of two families with familial hematuria, respectively. Our study broadened the variant spectrum of the COL4A4 gene and explained the possible pathogenesis, which will benefit clinical management and genetic counseling.

Case report: Characterization of a rare pathogenic variant associated with loss of COL3A1 expression in vascular Ehlers Danlos syndrome

The vascular subtype of Ehlers Danlos Syndrome (vEDS) is a rare connective tissue disorder characterized by spontaneous arterial, bowel or organ rupture. The diagnosis of vEDS is established in a proband by identification of a heterozygous pathogenic variant in the alpha-1 gene of type III collagen (COL3A1) by molecular analysis. In this report, we present a case of vEDS with life threatening, spontaneous arterial dissections in association with an uncharacterized rare variant of COL3A1, exon19:c.1340G > A. Primary culture of patient skin fibroblasts followed by immunofluorescence revealed a complete absence of COL3A1 protein expression as well as altered morphology. Electron microscopy of the cultured fibroblasts showed abnormal vacuoles in the cytoplasm suggestive of a secretory defect. In this study, we have performed functional characterization of the COL3A1 exon19:c.1340G > A variant for the first time and this may now be classified as likely pathogenic in vEDS.

HOXA cluster antisense RNA 2 elevates KIAA1522 expression through microRNA-520d-3p and insulin like growth factor 2 mRNA binding protein 3 to promote the growth of vascular smooth muscle cells in thoracic aortic aneurysm

AIMS

Recently, long non-coding RNAs (lncRNAs) have been revealed to mediate smooth muscle dysfunction in thoracic aortic aneurysm (TAA). LncRNA HOXA-AS2 has been proposed to engage in the regulation of diverse diseases. However, its function in TAA remains unknown. This study aimed to reveal the role and mechanism of HOXA-AS2 in VSMCs which were implicated in TAA formation.

METHODS AND RESULTS

RT-qPCR or western blot was performed to detect RNA or protein expression levels. The role of HOXA-AS2 in VSMCs was explored by functional assays. The relationship among HOXA-AS2/miR-520d-3p/KIAA1522/IGF2BP3 was analysed via mechanism assays. HOXA-AS2 was detected to have significantly high expression in TAA tissues and function as an oncogene to promote proliferation of VSMCs, while inhibiting cell apoptosis (Figure 1, **P < 0.01). HOXA-AS2 was unveiled to bind with miR-520d-3p (Figure 2, *P < 0.05, **P < 0.01) and further up-regulate KIAA1522 to facilitate the growth of VSMCs (Figure 3-4, *P < 0.05, **P < 0.01). HOXA-AS2 was also found to recruit IGF2BP3 to stabilize KIAA1522 mRNA (Figure 5, **P < 0.01). All data were displayed as mean ± standard deviation.

CONCLUSIONS

HOXA-AS2 up-regulates KIAA1522 through targeting miR-520d-3p/IGF2BP3 to drive VSMC growth in TAA.

Nonsyndromic arteriopathy and aortopathy and vascular Ehlers-Danlos syndrome causing COL3A1 variants

Vascular Ehlers-Danlos syndrome (vEDS) is an autosomal dominant genetic disorder characterized by soft connective tissue vulnerability due to dysfunction of Type III collagen and caused by the pathogenic variants in COL3A1 gene. In the era of next-generation sequencing, multiple genes including COL3A1 can be simultaneously analyzed, and among patients suffering from aortopathy even without any other clinical features suggestive of vEDS, pathogenic COL3A1 variants have been increasingly identified. Here, we briefly summarize the characteristics of 12 Japanese patients from 11 families with arteriopathy and pathogenic or likely pathogenic COL3A1 variants in our hospital. Five patients did not have any extra-arterial clinical features, however, the multigene panel testing for hereditary thoracic aortic aneurysm and dissection unexpectedly revealed that two had glycine substitutions in the triple-helical region and three had haploinsufficient type variants in the COL3A1 gene, whose pathogenicities were all classified as pathogenic or likely pathogenic. Further genetic screening and identification of pathogenic variants in patients with nonsyndromic arteriopathy and aortopathy will enable us to develop risk-stratification and management based on the genetic diagnosis.

Evaluating perinatal and neonatal outcomes among children with vascular Ehlers-Danlos syndrome

PURPOSE

Birth outcomes data for patients with vascular Ehlers-Danlos syndrome (VEDS) are limited.

METHODS

Patients with a pathogenic or likely pathogenic COL3A1 variant were included. Outcomes included gestational age (GA), birthweight (BW), and maternal complications. Birth outcomes were first compared with that of US population data, then compared by sex, maternal affected status, and COL3A1 genotype.

RESULTS

A total of 41 children were included (70.7% male), including 32 with high-risk (missense and splice site) variants. Preterm birth (<37 weeks) was more common in patients with VEDS than in the US population (48.8% vs 12.2%, P < .0001). Low BW (<2.5 kg) was also more common in patients with VEDS than in the US population (P < .0001), although, it was appropriate after GA adjustment (median GA-adjusted z-score 0.01 vs z-score 0.0, P = .26). No differences in GA or BW were observed by sex or maternal affected status. Those with high-risk variants were more likely to be born preterm than those with haploinsufficient variants, although this did not meet significance criteria (53% vs 33%, P = .35). Of the 6 affected mothers, 5 had perinatal complications.

CONCLUSION

Preterm birth is more common in children with VEDS than in the general population. Maternal affected status is not associated with preterm birth, suggesting that risk is conferred by the fetal VEDS diagnosis alone.

Dissecting the Heterogeneity of Human Thoracic Aortic Aneurysms Using Single-Cell Transcriptomics

Thoracic aortic aneurysm is a life-threatening condition caused by weakening of the thoracic aorta wall, often developing silently until dissection or rupture occurs. Despite substantial efforts in the past decade, there have been no significant therapeutic advances to prevent or clinically manage diverse forms of thoracic aortic aneurysm and dissection with the only effective treatment being surgical repair. There is an urgent need to understand intra- and inter-aneurysmal heterogeneity underlying thoracic aortic aneurysm and dissection pathogenesis. The human aortic wall consists of many cell types and exhibits significant regional heterogeneity. High-throughput single-cell RNA sequencing has emerged as the principal tool to reveal the complexity in human tissues and clinical specimens. Recent single-cell RNA sequencing studies of different aortic cell populations both in vivo and in vitro began to dissect this complexity and have provided valuable information. In this review, we summarize these findings and discuss the potential applications of single-cell transcriptomics and related high-content technologies in human thoracic aortic aneurysm and dissection research, as well as the challenges associated with it.

Update on the molecular landscape of thoracic aortic aneurysmal disease

PURPOSE OF THE REVIEW

Thoracic aortic aneurysms and dissections (TAADs) are a major health problem in the Western population. This review summarises recent discoveries in the genetic landscape of TAAD disease, discusses current challenges in clinical practice, and describes the molecular road ahead in TAAD research. Disorders, in which aneurysmal disease is not observed in the thoracic aorta, are not discussed.

RECENT FINDINGS

Current gene discovery studies have pinpointed about 40 genes associated with TAAD risk, accounting for about 30% of the patients. Importantly, novel genes, and their subsequent functional characterisation, have expanded the knowledge on disease-related pathways providing crucial information on key elements in this disease, and it pinpoints new therapeutic targets. Moreover, current molecular evidence also suggests the existence of less monogenic nature of TAAD disease, in which the presentation of a diseased patient is most likely influenced by a multitude of genetic and environmental factors.

SUMMARY CLINICAL PRACTICE/RELEVANCE

Ongoing molecular genetic research continues to expand our understanding on the pathomechanisms underlying TAAD disease in order to improve molecular diagnosis, optimise risk stratification, advance therapeutic strategies and facilitate counselling of TAAD patients and their families.

Genetics of Heritable Thoracic Aortic Disease

Genetic testing plays an increasing diagnostic and prognostic role in the management of patients with heritable thoracic aortic disease (HTAD). The identification of a specific variant can establish or confirm the diagnosis of syndromic HTAD, dictate extensive evaluation of the arterial tree in HTAD with known distal vasculature involvement and justify closer follow-up and earlier surgical intervention in HTAD with high risk of dissection of minimal or normal aortic size. Evolving phenotype–genotype correlations lead us towards more precise and individualized management and treatment of patients with HTAD. In this review, we present the latest evidence regarding the role of genetics in patients with HTAD.

Biomarkers in EndoVascular Aneurysm Repair (EVAR) and Abdominal Aortic Aneurysm: Pathophysiology and Clinical Implications

Circulating biomarkers have been recently investigated among patients undergoing endovascular aortic aneurysm repair (EVAR) for abdominal aortic aneurysm (AAA). Considering the plethora of small descriptive studies reporting potential associations between biomarkers and clinical outcomes, this review aims to summarize the current literature considering both the treated disease (post EVAR) and the untreated disease (AAA before EVAR). All studies describing outcomes of tissue biomarkers in patients undergoing EVAR and in patients with AAA were included, and references were checked for additional sources. In the EVAR scenario, circulating interleukin-6 (IL-6) is a marker of inflammatory reaction which might predict postoperative morbidity; cystatin C is a promising early marker of post-procedural acute kidney injury; plasma matrix metalloproteinase-9 (MMP-9) concentration after 3 months from EVAR might help in detecting post-procedural endoleak. This review also summarizes the current gaps in knowledge and future direction of this field of research. Among markers used in patients with AAA, galectin and granzyme appear to be promising and should be carefully investigated even in the EVAR setting. Larger prospective trials are required to establish and evaluate prognostic models with highest values with these markers.

Four decades in the making: Collagen III and mechanisms of vascular Ehlers Danlos Syndrome

Vascular Ehlers Danlos (vEDS) syndrome is a severe multi-systemic connective tissue disorder characterized by risk of dissection and rupture of the arteries, gastro-intestinal tract and gravid uterus. vEDS is caused by mutations in COL3A1, that encodes the alpha 1 chain of type III collagen, which is a major extracellular matrix component of the vasculature and hollow organs. The first causal mutations were identified in the 1980s but progress in our understanding of the pathomolecular mechanisms has been limited. Recently, the application of more refined animal models combined with global omics approaches has yielded important new insights both in terms of disease mechanisms and potential for therapeutic intervention. However, it is also becoming apparent that vEDS is a complex disorder in terms of its molecular disease mechanisms with a poorly understood allelic and mechanistic heterogeneity. In this brief review we will focus our attention on the disease mechanisms of COL3A1 mutations and vEDS, and recent progress in therapeutic approaches using animal models.

Global proteomic analysis of extracellular matrix in mouse and human brain highlights relevance to cerebrovascular disease

The extracellular matrix (ECM) is a key interface between the cerebrovasculature and adjacent brain tissues. Deregulation of the ECM contributes to a broad range of neurological disorders. However, despite this importance, our understanding of the ECM composition remains very limited mainly due to difficulties in its isolation. To address this, we developed an approach to extract the cerebrovascular ECM from mouse and human post-mortem normal brain tissues. We then used mass spectrometry with off-line high-pH reversed-phase fractionation to increase the protein detection. This identified more than 1000 proteins in the ECM-enriched fraction, with > 66% of the proteins being common between the species. We report 147 core ECM proteins of the human brain vascular matrisome, including collagens, laminins, fibronectin and nidogens. We next used network analysis to identify the connection between the brain ECM proteins and cerebrovascular diseases. We found that genes related to cerebrovascular diseases, such as COL4A1, COL4A2, VCAN and APOE were significantly enriched in the cerebrovascular ECM network. This provides unique mechanistic insight into cerebrovascular disease and potential drug targets. Overall, we provide a powerful resource to study the functions of brain ECM and highlight a specific role for brain vascular ECM in cerebral vascular disease.

Identification of Hub Genes Associated with the Pathogenesis of Intracranial Aneurysm via Integrated Bioinformatics Analysis

BACKGROUND

At present, the pathogenesis of intracranial aneurysms (IA) remains unclear, which significantly hinders the development of novel strategies for the clinical treatment. In this study, bioinformatics methods were used to identify the potential hub genes and pathways associated with the pathogenesis of IA.

METHODS

The gene expression datasets of patients with intracranial aneurysm were downloaded from the Gene Expression Database (GEO), and the different data sets were integrated by the robust rank aggregation (RRA) method to identify the differentially expressed genes between patients with intracranial aneurysm and the controls. The functional enrichment analyses of the significant differentially expressed genes (DEGs) were performed and the protein-protein interaction (PPI) network was constructed; thereafter, the hub genes were screened by cytoHubba plug-in of Cytoscape, and finally sequencing dataset GSE122897 was used to verify the hub genes.

RESULTS

The GSE15629, GSE75436, GSE26969, and GSE6551 expression profiles have been included in this study, including 34 intracranial aneurysm samples and 26 control samples. The four datasets obtained 136 significant DEGs (45 up-regulated, 91 down-regulated). Enrichment analysis showed that the extracellular matrix structural constituent and the ECM-receptor interaction were closely related to the occurrence of IA. It was finally determined that eight hub genes associated with the development of IA, including VCAN, COL1A1, COL11A1, COL5A1, COL5A2, POSTN, THBS2, and CDH2.

CONCLUSION

The discovery of potential hub genes and pathways could enhance the understanding of the molecular mechanisms associated with the development of IA. These hub genes may be potential therapeutic targets for the management and new biomarker for the diagnosis of IA.

Molecular phenotyping and functional assessment of smooth muscle like-cells with pathogenic variants in aneurysm genes ACTA2, MYH11, SMAD3 and FBN1

Aortic aneurysms (AAs) are pathological dilatations of the aorta. Pathogenic variants in genes encoding for proteins of the contractile machinery of vascular smooth muscle cells (VSMCs), genes encoding proteins of the transforming growth factor beta signaling pathway and extracellular matrix (ECM) homeostasis play a role in the weakening of the aortic wall. These variants affect the functioning of VSMC, the predominant cell type in the aorta. Many variants have unknown clinical significance, with unknown consequences on VSMC function and AA development. Our goal was to develop functional assays that show the effects of pathogenic variants in aneurysm-related genes. We used a previously developed fibroblast transdifferentiation protocol to induce VSMC-like cells, which are used for all assays. We compared transdifferentiated VSMC-like cells of patients with a pathogenic variant in genes encoding for components of VSMC contraction (ACTA2, MYH11), transforming growth factor beta (TGFβ) signaling (SMAD3) and a dominant negative (DN) and two haploinsufficient variants in the ECM elastic laminae (FBN1) to those of healthy controls. The transdifferentiation efficiency, structural integrity of the cytoskeleton, TGFβ signaling profile, migration velocity and maximum contraction were measured. Transdifferentiation efficiency was strongly reduced in SMAD3 and FBN1 DN patients. ACTA2 and FBN1 DN cells showed a decrease in SMAD2 phosphorylation. Migration velocity was impaired for ACTA2 and MYH11 cells. ACTA2 cells showed reduced contractility. In conclusion, these assays for showing effects of pathogenic variants may be promising tools to help reclassification of variants of unknown clinical significance in AA-related genes.

Deletion of fibroblast activation protein provides atheroprotection

AIMS

Fibroblast activation protein (FAP) is upregulated at sites of tissue remodelling including chronic arthritis, solid tumours, and fibrotic hearts. It has also been associated with human coronary atherosclerotic plaques. Yet, the causal role of FAP in atherosclerosis remains unknown. To investigate the cause-effect relationship of endogenous FAP in atherogenesis, we assessed the effects of constitutive Fap deletion on plaque formation in atherosclerosis-prone apolipoprotein E (Apoe) or low-density lipoprotein receptor (Ldlr) knockout mice.

METHODS AND RESULTS

Using en face analyses of thoraco-abdominal aortae and aortic sinus cross-sections, we demonstrate that Fap deficiency decreased plaque formation in two atherosclerotic mouse models (-46% in Apoe and -34% in Ldlr knockout mice). As a surrogate of plaque vulnerability fibrous cap thickness was used; it was increased in Fap-deficient mice, whereas Sirius red staining demonstrated that total collagen content remained unchanged. Using polarized light, atherosclerotic lesions from Fap-deficient mice displayed increased FAP targets in terms of enhanced collagen birefringence in plaques and increased pre-COL3A1 expression in aortic lysates. Analyses of the Stockholm Atherosclerosis Gene Expression data revealed that FAP expression was increased in human atherosclerotic compared to non-atherosclerotic arteries.

CONCLUSIONS

Our data provide causal evidence that constitutive Fap deletion decreases progression of experimental atherosclerosis and increases features of plaque stability with decreased collagen breakdown. Thus, inhibition of FAP expression or activity may not only represent a promising therapeutic target in atherosclerosis but appears safe at the experimental level for FAP-targeted cancer therapies.

LncRNA Xist induces arterial smooth muscle cell apoptosis in thoracic aortic aneurysm through miR-29b-3p/Eln pathway

BACKGROUND

Thoracic aortic aneurysm (TAA) is a serious disease usually happening in elder people and with high death rate. Accumulating studies have reported that long non-coding RNAs (lncRNAs) are implicated in the progression of various human diseases, including TAA.

AIM

In our study, we intended to explore the function of elastin (Eln) and its upstream mechanism in TAA.

METHODS

RT-qPCR determined gene expressions and western blot tested changes in protein levels. Ang Ⅱ treatment was implemented to induce cell apoptosis. Flow cytometry analysis, TUNEL assay and JC-1 assay were exploited to measure cell apoptosis. Meanwhile, mechanistic assays such as RIP, RNA pull down and luciferase reporter assays were employed to identify the interplay between RNAs.

RESULTS

Eln inhibition was identified to protect rat arterial smooth muscle cells from apoptosis. Also, miR-29b-3p was identified to bind to Eln, and X inactive specific transcript (Xist) could boost Eln expression through absorbing miR-29b-3p. Meanwhile, Eln overexpression counteracted the suppression of silenced Xist on the apoptosis of rat arterial smooth muscle cells. More importantly, such ceRNA network was proved to aggravate the apoptosis of human aortic smooth muscle cells.

CONCLUSION

LncRNA Xist contributes to arterial smooth muscle cell apoptosis through miR-29b-3p/Eln pathway, providing new potential roads for treating TAA.

Insights on the Pathogenesis of Aneurysm through the Study of Hereditary Aortopathies

Thoracic aortic aneurysms (TAA) are permanent and localized dilations of the aorta that predispose patients to a life-threatening risk of aortic dissection or rupture. The identification of pathogenic variants that cause hereditary forms of TAA has delineated fundamental molecular processes required to maintain aortic homeostasis. Vascular smooth muscle cells (VSMCs) elaborate and remodel the extracellular matrix (ECM) in response to mechanical and biochemical cues from their environment. Causal variants for hereditary forms of aneurysm compromise the function of gene products involved in the transmission or interpretation of these signals, initiating processes that eventually lead to degeneration and mechanical failure of the vessel. These include mutations that interfere with transduction of stimuli from the matrix to the actin-myosin cytoskeleton through integrins, and those that impair signaling pathways activated by transforming growth factor-β (TGF-β). In this review, we summarize the features of the healthy aortic wall, the major pathways involved in the modulation of VSMC phenotypes, and the basic molecular functions impaired by TAA-associated mutations. We also discuss how the heterogeneity and balance of adaptive and maladaptive responses to the initial genetic insult might contribute to disease.

Extracellular Matrix in Vascular Disease, Part 2/4: JACC Focus Seminar

Medium-sized and large arteries consist of 3 layers: the tunica intima, tunica media, and tunica adventitia. The tunica media accounts for the bulk of the vessel wall and is the chief determinant of mechanical compliance. It is primarily composed of circumferentially arranged layers of vascular smooth muscle cells that are separated by concentrically arranged elastic lamellae; a form of extracellular matrix (ECM). The tunica media is separated from the tunica intima and tunica adventitia, the innermost and outermost layers, respectively, by the internal and external elastic laminae. This second part of a 4-part JACC Focus Seminar discusses the contributions of the ECM to vascular homeostasis and pathology. Advances in genetics and proteomics approaches have fostered significant progress in our understanding of vascular ECM. This review highlights the important role of the ECM in vascular disease and the prospect of translating these discoveries into clinical disease biomarkers and potential future therapies.

Backcrossing to an appropriate genetic background improves the birth rate of carbohydrate sulfotransferase 14 gene-deleted mice

Ehlers–Danlos syndromes (EDSs) are heterogeneous group of heritable connective tissue disorders characterized by joint and skin hyperextensibility as well as fragility of various organs. Recently, we described a new type of EDS, musculocontractual EDS (mcEDS-CHST14), caused by pathogenic variants of the carbohydrate sulfotransferase 14 (CHST14) gene mutation. B6;129S5-Chst14^tm1Lex/Mmucd (B6;129-Chst14 KO) mice are expected to be an animal model of mcEDS-CHST14. However, >90% of B6;129-Chst14 KO homozygous (B6;129-Chst14^−/−) mice show perinatal lethality. Therefore, improvement of the birth rate of Chst14^−/− mice is needed to clarify the pathophysiology of mcEDS-CHST14 using this animal model. Some B6;129-Chst14^−/− embryos had survived at embryonic day 18.5 in utero, suggesting that problems with delivery and/or childcare may cause perinatal lethality. However, in vitro fertilization and egg transfer did not improve the birth rate of the mice. A recent report showed that backcrossing to C57BL/6 strain induces perinatal death of all Chst14^−/− mice, suggesting that genetic background influences the birthrate of these mice. In the present study, we performed backcrossing of B6;129-Chst14 KO mice to a BALB/c strain, an inbred strain that shows lower risks of litter loss than C57BL/6 strain. Upon backcrossing 1 to 12 times, the birth rate of Chst14^−/− mice was improved with a birth rate of 6.12–18.64%. These results suggest that the genetic background influences the birth rate of Chst14^−/− mice. BALB/c congenic Chst14^−/− (BALB.Chst14^−/−) mice may facilitate investigation of mcEDS-CHST14. Furthermore, backcrossing to an appropriate strain may contribute to optimizing animal experiments.

Identification of a Novel CCM1 Frameshift Mutation in a Chinese Han Family With Multiple Cerebral Cavernous Malformations

Cerebral cavernous malformations (CCMs) are vascular lesions that predominantly occur in the brain. CCMs can be sporadic or hereditary in an autosomal dominant manner. The genes harboring variants of familial CCMs (FCCMs) include CCM1/KRIT1, CCM2/MGC4607, and CCM3/PDCD10. In this study, we identified a novel CCM1/KRIT1 mutation in a Chinese family with FCCMs. This family consists of 20 members, and 6 of them had been diagnosed with CCMs. The proband patient is a 17-year-old female who has suffered from CCM-related intracranial hemorrhage four times. Magnetic resonance imaging (MRI) revealed four lesions in the different brain regions and one lesion has progressively enlarged. The pathological histology confirmed CCMs. Whole exome sequencing revealed a novel deletion mutation (c.1635delA) within exon 15 of CCM1/KRIT1 gene in the proband patient, her mother, and her uncle who had CCMs. This frameshift mutation led to a premature termination codon (PTC) at nucleotides 1652-1654. We also detected that the CCM1 mRNA levels in the blood lymphocytes of the family members with CCMs were reduced by 46.4% compared to that in healthy controls. Collectively, our results suggested that the CCM1 mutation could potentially be a causative factor for FCCMs in the Chinese family and the reduction of CCM1 mRNA expression in the blood lymphocytes of the patients might be a potential biomarker for the diagnosis and prognosis of CCMs. Our findings expanded the spectrum of CCM mutations and helped to guide genetic counseling and early genetic diagnosis for at-risk family members.

Current management of the vascular subtype of Ehlers-Danlos syndrome

PURPOSE OF REVIEW

Vascular Ehlers-Danlos syndrome (vEDS) is the most severe form of EDS, affecting the synthesis of type III collagen. It is notable for decreased life expectancy and morbidity, including spontaneous vessel rupture. The present review summarizes recent findings that have improved the ability to manage and delineate the natural history of vEDS.

RECENT FINDINGS

Recent EDS consortium guidelines for the diagnosis of vEDS have emerged and outlined clinical features and molecular diagnostic tools to help facilitate rapid diagnosis. Although medical interventions to help halt the disease progression remain limited, improved awareness of vEDS by patients and practitioners have resulted in increased average life expectancy. Early excitement with celiprolol has been tempered by a lack of high-quality studies. Likewise, the creation of multidisciplinary care teams and tertiary referral centers is helping improve outcomes. Unfortunately, there remain limitations in terms of the surgical management (including more advanced endovascular techniques) of these patients and the morbidity associated with these interventions.

SUMMARY

Although new consensus guidelines have emerged to facilitate the diagnosis of those with vEDS, there remain limitations in terms of interventions and medical therapy that can be provided for these patients. Life expectancy does appear to be improving however with increased awareness and coordinated multidisciplinary efforts among medical geneticists, general practitioners, and interventionalists alike.

The Ehlers-Danlos syndromes

The Ehlers-Danlos syndromes (EDS) are a heterogeneous group of hereditary disorders of connective tissue, with common features including joint hypermobility, soft and hyperextensible skin, abnormal wound healing and easy bruising. Fourteen different types of EDS are recognized, of which the molecular cause is known for 13 types. These types are caused by variants in 20 different genes, the majority of which encode the fibrillar collagen types I, III and V, modifying or processing enzymes for those proteins, and enzymes that can modify glycosaminoglycan chains of proteoglycans. For the hypermobile type of EDS, the molecular underpinnings remain unknown. As connective tissue is ubiquitously distributed throughout the body, manifestations of the different types of EDS are present, to varying degrees, in virtually every organ system. This can make these disorders particularly challenging to diagnose and manage. Management consists of a care team responsible for surveillance of major and organ-specific complications (for example, arterial aneurysm and dissection), integrated physical medicine and rehabilitation. No specific medical or genetic therapies are available for any type of EDS.

Recurrent pneumothorax and intrapulmonary cavitary lesions in a male patient with vascular Ehlers-Danlos syndrome and a novel missense mutation in the COL3A1 gene: a case report

Background

Vascular Ehlers-Danlos syndrome (vEDS) is a rare autosomal dominant hereditary collagen disease caused by a defect or deficiency in the pro-α1 chain of type III procollagen encoded by the COL3A1 gene. Patients with vEDS rarely present with multiple pneumothoraces. The clinical features of this disease are not familiar to clinicians and are easily missed. We report a patient with a novel missense mutation in the COL3A1 gene (NM_000090.3: c.2977G > A) and hope to provide clinicians with valuable information.

Case presentation

We reported the case of a young man presenting with frequent episodes of pneumothorax and intrapulmonary cavities and nodular lesions without arterial or visceral complications. His skin was thin and transparent, and the joints were slightly hypermobile. Whole-exome sequencing (chip capture high-throughput sequencing) revealed a heterozygous missense mutation in exon 41 of the COL3A1 gene (NM_000090.3: c.2977G > A), confirming the diagnosis of vEDS. vEDS remains a very rare and difficult diagnosis to determine.

Conclusion

When a patient presents with recurrent pneumothorax, intrapulmonary cavities and nodular lesions, thin and transparent skin, and hypermobile joints, clinicians should consider the diagnosis of vEDS.

Vascular Ehlers-Danlos Syndrome: Literature review and surgical management of intracranial vascular complications

Vascular Ehlers-Danlos (vEDS) is a rare form of the Ehlers-Danlos Syndrome (EDS) where arterial fragility results from mutations in the gene that encodes type III collagen. The disease can lead to major neurological complications including carotico-cavernous fistulae (CCF), aneurysms of the Circle of Willis and endovascular procedures have an increased risk profile due to the delicate vasculature. Management of intracranial disease in vEDS requires an intricate understanding of the syndrome but is still associated with significant complications that lead to morbidity and mortality. As well as providing an approach to the management of neurovascular complications in vEDS, the relevant literature regarding nosology, aetiology and genetics of the condition is summarised here. Particular emphasis is placed on the two most common intracranial complications, namely carotico-cavernous fistulas and and cerebral aneurysms. Pros and cons of surgical and endovascular interventions are discussed and a technical discussion is concentrated on the surgical aspects of management.

Setting a research agenda for vascular Ehlers-Danlos syndrome using a patient and stakeholder engagement model

OBJECTIVE

Vascular Ehlers-Danlos syndrome (vEDS) is a rare, syndromic, heritable condition with life-threatening complications that include aortic and arterial aneurysms, dissection, and rupture. This study describes the formation of the vEDS Research Collaborative and methods used for stakeholder engagement.

METHODS

The vEDS Research Collaborative was established with an engagement award from the Patient-Centered Outcomes Research Institute to create a framework for a patient-researcher partnership. Between October 1, 2017, and September 30, 2018, the Collaborative used the Patient-Centered Outcomes Research Institute Engagement Rubric to conduct stakeholder engagement to develop a patient-centered research agenda. A modified Delphi technique was used to develop and to refine research topics and questions, gathering input from all stakeholders during three rounds of feedback.

RESULTS

Four topic areas were deemed important: mental health and quality of life issues, creating a care team, a holistic approach to vEDS management (medical and surgical), and pregnancy management. An online survey to rank a list of 12 research questions in these topic areas in order of importance was disseminated. The questions were ranked in order of importance through an online survey (N = 197 responses). The survey showed a high degree of alignment in the top priorities among stakeholders. There was a high degree of interest in pragmatic clinical trials evaluating medical management options and health-related quality of life outcomes.

CONCLUSIONS

The vEDS Research Collaborative has built a sustainable, coalition model of patient and stakeholder engagement, supported by the vEDS community, to identify a patient-centered, prioritized list of research questions. In articulating a shared vision for the future of vEDS research, the Collaborative has laid the groundwork for developing research protocols aligned with the highest priority questions for the individuals affected by this serious condition that can be translated into future clinical trials.

The Genetics of Thoracic Aortic Aneurysms and Dissection: A Clinical Perspective

Thoracic aortic aneurysm and dissection (TAAD) affects many patients globally and has high mortality rates if undetected. Once thought to be solely a degenerative disease that afflicted the aorta due to high pressure and biomechanical stress, extensive investigation of the heritability and natural history of TAAD has shown a clear genetic basis for the disease. Here, we review both the cellular mechanisms and clinical manifestations of syndromic and non-syndromic TAAD. We particularly focus on genes that have been linked to dissection at diameters <5.0 cm, the current lower bound for surgical intervention. Genetic screening tests to identify patients with TAAD associated mutations that place them at high risk for dissection are also discussed.

A multi-institutional experience in vascular Ehlers-Danlos syndrome diagnosis

OBJECTIVE

Vascular Ehlers-Danlos syndrome (vEDS) is a rare disorder and 1 of 13 types of EDS. The syndrome results in aortic and arterial aneurysms and dissections at a young age. Diagnosis is confirmed with molecular testing via skin biopsy or genetic testing for COL3A1 pathogenic variants. We describe a multi-institutional experience in the diagnosis of vEDS from 2000 to 2015.

METHODS

This is a multi-institutional cross-sectional retrospective study of individuals with vEDS. The institutions were recruited through the Vascular Low Frequency Disease Consortium. Individuals were identified using the International Classification of Diseases-9 and 10-CM codes for EDS (756.83 and Q79.6). A review of records was then performed to select individuals with vEDS. Data abstraction included demographics, family history, clinical features, major and minor diagnostic criteria, and molecular testing results. Individuals were classified into two cohorts and then compared: those with pathogenic COL3A1 variants and those diagnosed by clinical criteria alone without molecular confirmation.

RESULTS

Eleven institutions identified 173 individuals (35.3% male, 56.6% Caucasian) with vEDS. Of those, 11 (9.8%) had nonpathogenic alterations in COL3A1 and were excluded from the analysis. Among the remaining individuals, 86 (47.7% male, 68% Caucasian, 48.8% positive family history) had pathogenic COL3A1 variants and 76 (19.7% male, 19.7% Caucasian, 43.4% positive family history) were diagnosed by clinical criteria alone without molecular confirmation. Compared with the cohort with pathogenic COL3A1 variants, the clinical diagnosis only cohort had a higher number of females (80.3% vs 52.3%; P < .001), mitral valve prolapse (10.5% vs 1.2%; P = .009), and joint hypermobility (68.4% vs 40.7%; P < .001). Additionally, they had a lower frequency of easy bruising (23.7% vs 64%; P < .001), thin translucent skin (17.1% vs 48.8%; P < .001), intestinal perforation (3.9% vs 16.3%; P = .01), spontaneous pneumothorax/hemothorax (3.9% vs 14%, P.03), and arterial rupture (9.2% vs 17.4%; P = .13). There were no differences in mortality or age of mortality between the two cohorts.

CONCLUSIONS

This study highlights the importance of confirming vEDS diagnosis by testing for pathogenic COL3A1 variants rather than relying on clinical diagnostic criteria alone given the high degree of overlap with other forms genetically triggered arteriopathies. Because not all COL3A1 variants are pathogenic, the interpretation of the genetic testing results by an individual trained in variant assessment is essential to confirm the diagnosis. An accurate diagnosis is critical and has serious implications for lifelong screening and treatment strategies for the affected individual and family members.

Restoring extracellular matrix synthesis in senescent stem cells

Collagen type III (COL3) is one of the 3 major collagens in the body, and loss of expression or mutations in the COL3 gene have been associated with the onset of vascular diseases such the Ehlers-Danlos syndrome. Previous work reported a significant reduction of COL3 in tissues such as skin and vessels with aging. In agreement, we found that COL3 was significantly reduced in senescent human mesenchymal stem cells and myofibroblasts derived from patients with Hutchinson-Gilford progeria syndrome, a premature aging syndrome. Most notably, we discovered that ectopic expression of the embryonic transcription factor Nanog homeobox (NANOG) restored COL3 expression by restoring the activity of the TGF-β pathway that was impaired in senescent cells. RNA sequencing analysis showed that genes associated with the activation of the TGF-β pathway were up-regulated, whereas negative regulators of the pathway were down-regulated upon NANOG expression. Chromatin immunoprecipitation sequencing and immunoprecipitation experiments revealed that NANOG bound to the mothers against decapentaplegic (SMAD)2 and SMAD3 promoters, in agreement with increased expression and phosphorylation levels of both proteins. Using chemical inhibition, short hairpin RNA knockdown, and gain of function approaches, we established that both SMAD2 and SMAD3 were necessary to mediate the effects of NANOG, but SMAD3 overexpression was also sufficient for COL3 production. In summary, NANOG restored production of COL3, which was impaired by cellular aging, suggesting novel strategies to restore the impaired extracellular matrix production and biomechanical function of aged tissues, with potential implications for regenerative medicine and anti-aging treatments.-Rong, N., Mistriotis, P., Wang, X., Tseropoulos, G., Rajabian, N., Zhang, Y., Wang, J., Liu, S., Andreadis, S. T. Restoring extracellular matrix synthesis in senescent stem cells.

LncRNA LOXL1-AS is up-regulated in thoracic aortic aneurysm and regulated proliferation and apoptosis of aortic smooth muscle cells

Long non-coding RNA LOXL1-AS is up-regulated in several types of cancers. The present study was carried out to explore the potential interactions between LOXL1-AS and lncRNA Giver in thoracic aortic aneurysm (TAA). We found that LOXL1-AS was up-regulated in TAA patients than in healthy controls in aortic media specimens. Altered expression levels of LOXL1-AS distinguished TAA patients from healthy controls. LncRNA Giver was also up-regulated in TAA patients than in healthy controls in aortic media specimens, and was positively correlated with LOXL1-AS. LOXL1-AS overexpression mediated the up-regulation of Giver in human aortic smooth muscle cells, while Giver overexpression failed to significantly affect LOXL1-AS. LOXL1-AS and Giver overexpression resulted in promoted proliferation and inhibited apoptosis of HAOSMC. Giver silencing played an opposite role and attenuated the effect of LOXL1-AS overexpression. Therefore, LOXL1-AS was up-regulated in TAA and regulated proliferation and apoptosis of LOXL1-AS by up-regulating Giver.

Assessment of the Information Sources and Interest in Research Collaboration Among Individuals with Vascular Ehlers-Danlos Syndrome

BACKGROUND

Patient-centered research requires active engagement of patients. The vascular Ehlers-Danlos Syndrome (vEDS) research collaborative was established to ascertain patient-centered vEDS research priorities and to engage affected individuals as research partners. Evaluation of access to information and interest in research among individuals with vEDS was the first step undertaken as part of this work.

METHODS

A 28-question survey was created to evaluate 4 domains of interest: diagnostic and clinical care history, vEDS experience, information resources, and willingness to collaborate with researchers. The survey was created in REDCap™ and disseminated between January and April 2018 via the vEDS social media pages, blogs, and advocacy Web sites. Results were collated and described. A single open-ended question yielded additional narrative data, which were analyzed qualitatively.

RESULTS

Of the 300 responses, 228 (76%) were completed on behalf of oneself. The vEDS diagnosis was confirmed by genetic testing for 85% of respondents. When asked "Did a physician explain vEDS to you and how to manage it?" 25% answered no. Most had a primary care provider (65%), cardiologist (56%), and vascular surgeon (52%). Only 32% had a local vascular surgeon. The most commonly reported frustration was no cure/treatment available and the emergency rooms do not know what VEDS is (64.5% and 61.8%, respectively). The Internet was the most useful information source (62.3%) followed by a geneticist (18.4%). Most (87.7%) are willing to share their medical records for research studies (87.7%) and wished to be contacted about future studies (83.8%); however, only 65.4% would be willing to upload medical records via a secure confidential Web application. The most common reason for interest in research partnership was to advance research for a treatment/cure (83.8%) and helping others learn from their experiences (82.9%). The qualitative analysis provided additional insights into the patient experience living with vEDS.

CONCLUSIONS

Among individuals with vEDS, there is substantial frustration with the lack of treatment, lack of knowledge among health care providers, and a high degree of interest in research involvement. The survey highlights an opportunity to discuss the optimal modality for research participation and methodologies for building trust in the research teams. The methodology lessons learned can also be applied to other rare vascular diseases.

Arteriopathy of Unknown Etiology: Pathologic, Radiologic, and Cytogenetic Investigations

Patient: Male, 38

Final Diagnosis: Arteriopathy of unknown etiology

Symptoms: Left groin pain

Medication: —

Clinical Procedure: —

Specialty: Neurology

Intestinal Perforation in Children as an Important Differential Diagnosis of Vascular Ehlers-Danlos Syndrome

Patient: Male, 6

Final Diagnosis: Colonic perforation secondary to vascular Ehlers Danlos Syndrome

Symptoms: Abdominal pain • constipation

Medication: —

Clinical Procedure: Loop colostomy followed by total colectomy and ileostomy

Specialty: Surgery

A multi-institutional experience in the aortic and arterial pathology in individuals with genetically confirmed vascular Ehlers-Danlos syndrome

OBJECTIVE

Vascular Ehlers-Danlos syndrome (vEDS) is a rare connective tissue disorder owing to pathogenic variants in COL3A1 that lead to impaired type III collagen production. We aim to describe the contemporary multi-institutional experience of aortic and arterial pathology in individuals with vEDS, to evaluate disease patterns and refine management recommendations.

METHODS

This cross-sectional, retrospective study of individuals with genetically confirmed vEDS was conducted between 2000 and 2015 at multiple institutions participating in the Vascular Low Frequency Disease Consortium. Aortic and arterial events including aneurysms, pseudoaneurysms, dissections, fistulae, or ruptures were studied. Demographics, COL3A1 variants, management, and outcomes data were collected and analyzed. Individuals with and without arterial events were compared.

RESULTS

Eleven institutions identified 86 individuals with pathogenic variants in COL3A1 (47.7% male, 86% Caucasian; median age, 41 years; interquartile range [IQR], 31.0-49.5 years; 65.1% missense COL3A1 variants). The median follow-up from the time of vEDS diagnosis was 7.5 years (IQR, 3.5-12.0 years). A total of 139 aortic/arterial pathologies were diagnosed in 53 individuals (61.6%; 50.9% male; 88.5% Caucasian; median age, 33 years; IQR, 25.0-42.3 years). The aortic/arterial events presented as an emergency in 52 cases (37.4%). The most commonly affected arteries were the mesenteric arteries (31.7%), followed by cerebrovascular (16.5%), iliac (16.5%), and renal arteries (12.2%). The most common management was medical management. When undertaken, the predominant endovascular interventions were arterial embolization of medium sized arteries (13.4%), followed by stenting (2.5%). Aortic pathology was noted in 17 individuals (32%; 58.8% male; 94.1% Caucasian; median age, 38.5 years; IQR, 30.8-44.7 years). Most notably, four individuals underwent successful abdominal aortic aneurysm repair with excellent results on follow-up. Individuals with missense mutations, in which glycine was substituted with a large amino acid, had an earlier onset of aortic/arterial pathology (median age, 30 years; IQR, 23.5-37 years) compared with the other pathogenic COL3A1 variants (median age, 36 years; IQR, 29.5-44.8 years; P = .065). There were 12 deaths (22.6%) at a median age of 36 years (IQR, 28-51 years).

CONCLUSIONS

Most of the vEDS arterial manifestations were managed medically in this cohort. When intervention is required for an enlarging aneurysm or rupture, embolization, and less frequently stenting, seem to be well-tolerated. Open repair of abdominal aortic aneurysm seems to be as well-tolerated as in those without vEDS; vEDS should not be a deterrent to offering an operation. Future work to elucidate the role of surgical interventions and refine management recommendations in the context of patient centered outcomes is warranted.

Atypical COL3A1 variants (glutamic acid to lysine) cause vascular Ehlers-Danlos syndrome with a consistent phenotype of tissue fragility and skin hyperextensibility

PURPOSE

The Ehlers-Danlos syndromes (EDS) are a group of rare inherited connective tissue disorders. Vascular EDS (vEDS) is caused by pathogenic variants in COL3A1, most frequently glycine substitutions. We describe the phenotype of the largest series of vEDS patients with glutamic acid to lysine substitutions (Glu>Lys) in COL3A1, which were all previously considered to be variants of unknown significance.

METHODS

Clinical and molecular data for seven families with three different Glu>Lys substitutions in COL3A1 were analyzed.

RESULTS

These Glu>Lys variants were reclassified from variants of unknown significance to either pathogenic or likely pathogenic in accordance with American College of Medical Genetics and Genomics guidelines. All individuals with these atypical variants exhibited skin hyperextensibility as seen in individuals with classical EDS and classical-like EDS and evidence of tissue fragility as seen in individuals with vEDS.

CONCLUSION

The clinical data demonstrate the overlap between the different EDS subtypes and underline the importance of next-generation sequencing gene panel analysis. The three different Glu>Lys variants point toward a new variant type in COL3A1 causative of vEDS, which has consistent clinical features. This is important knowledge for COL3A1 variant interpretation. Further follow-up data are required to establish the severity of tissue fragility complications compared with patients with other recognized molecular causes of vEDS.

Accuracy of Clinical Diagnostic Criteria for Patients With Vascular Ehlers-Danlos Syndrome in a Tertiary Referral Centre

Background:

Vascular Ehlers-Danlos syndrome is a rare inherited connective tissue disease secondary to mutations within the COL3A1 gene. The diagnosis of vascular Ehlers-Danlos syndrome is challenging, and patient selection for genetic testing relies on diagnostic criteria, which have never been evaluated.

Methods:

All patients seen at a dedicated tertiary referral center for a suspicion of vascular Ehlers-Danlos syndrome between January 2001 and March 2016 were retrospectively included in a diagnostic accuracy study. Major and minor diagnostic criteria of the Villefranche classification were tested for sensitivity, specificity, positive and negative predictive values, according to results of genetic testing.

Results:

N=519 patients were eligible for analysis dividing into n=384 probands and n=135 relatives. A pathogenic COL3A1 variant was identified in n=165 (31.8%) patients. The Villefranche criteria were met for n=248 patients with a sensitivity of 79% (95% CI, 0.72–0.85) and a negative predictive value of 87% (95% CI, 0.83–0.91). Diagnostic accuracy was highest for symptomatic probands (sensitivity 92%; negative predictive value 95%) with limited specificity (60%). Probands ≤25 years had the worst diagnostic performance. The revised diagnostic Criteria (2017) were less accurate than the Villefranche classification (overall diagnostic odds-ratio, 4.17 versus 7.8; probands diagnostic odds-ratio, 4.04 versus 18.1; and probands ≤25 years diagnostic odds-ratio, 2.36 versus 5.1) mainly due to a lack of sensitivity.

Conclusions:

The Villefranche criteria provide accurate detection of symptomatic probands in specialized practice but have limited specificity. The revised diagnostic criteria for vascular Ehlers-Danlos syndrome have increased specificity, but its overall performance is poorer. The early clinical diagnosis of probands without family history is not addressed by both diagnostic classifications.

Vascular abnormalities in the placenta of Chst14-/- fetuses: implications in the pathophysiology of perinatal lethality of the murine model and vascular lesions in human CHST14/D4ST1 deficiency

Collagen is one of the most important components of the extracellular matrix that is involved in the strength of tissues, cell adhesion and cell proliferation. Mutations in several collagen and post-translational modification enzyme genes cause Ehlers-Danlos syndrome (EDS) characterized by joint and skin hyperextensibility as well as fragility of various organs. Carbohydrate sulfotransferase 14/dermatan 4-O-sulfotransferase-1 (CHST14/D4ST1) is a critical enzyme for biosynthesis of dermatan sulfate, a side chain of various proteoglycans including biglycan that regulates collagen fibrils through their interaction. Mutations in CHST14 were found to cause a new form of EDS, named musculocontractural type EDS (mcEDS-CHST14). Large subcutaneous hematomas are one of the most serious complications accompanied by decreased quality of life and potential lethality. In this study, Chst14 gene-deleted mice were expected to be an animal model of the vascular abnormalities of mcEDS-CHST14. However, only limited numbers of adult mice were generated because of perinatal lethality in most Chst14 gene-deleted homozygote (Chst14-/-) mice. Therefore, we investigated the placentas of these fetuses. The placentas of Chst14-/- fetuses showed a reduced weight, alterations in the vascular structure, and ischemic and/or necrotic-like changes. Electron microscopy demonstrated an abnormal structure of the basement membrane of capillaries in the placental villus. These findings suggest that Chst14 is essential for placental vascular development and perinatal survival of fetuses. Furthermore, placentas of Chst14-/- fetuses could be a useful model for vascular manifestations in mcEDS-CHST14, such as the large subcutaneous hematomas.