Emerging importance of molecular pathogenesis of vascular malformations in clinical practice and classifications

Key biomarkers in cerebral arteriovenous malformations: Updated review

The formation of vascular networks consisting of arteries, capillaries, and veins is vital in embryogenesis. It is also crucial in adulthood for the formation of a functional vasculature. Cerebral arteriovenous malformations (CAVMs) are linked with a remarkable risk of intracerebral hemorrhage because arterial blood is directly shunted into the veins before the arterial blood pressure is dissipated. The underlying mechanisms responsible for arteriovenous malformation (AVM) growth, progression, and rupture are not fully known, yet the critical role of inflammation in AVM pathogenesis has been noted. The proinflammatory cytokines are upregulated in CAVM, which stimulates overexpression of cell adhesion molecules in endothelial cells (ECs), leading to improved leukocyte recruitment. It is well-known that metalloproteinase-9 secretion by leukocytes disrupts CAVM walls resulting in rupture. Moreover, inflammation alters the angioarchitecture of CAVMs by upregulating angiogenic factors impacting the apoptosis, migration, and proliferation of ECs. A better understanding of the molecular signature of CAVM might allow us to identify biomarkers predicting this complication, acting as a goal for further investigations that may be potentially targeted in gene therapy. The present review is focused on the numerous studies conducted on the molecular signature of CAVM and the associated hemorrhage. The association of numerous molecular signatures with a higher risk of CAVM rupture is shown through inducing proinflammatory mediators, as well as growth factors signaling, Ras-mitogen-activated protein kinase-extracellular signal-regulated kinase, and NOTCH pathways, which are accompanied by cellular level inflammation and endothelial alterations resulting in vascular wall instability. According to the studies, it is assumed that matrix metalloproteinase, interleukin-6, and vascular endothelial growth factor are the biomarkers most associated with CAVM and the rate of hemorrhage, as well as diagnostic methods, with respect to enhancing the patient-specific risk estimation and improving treatment choices.

Early experience of thalidomide therapy for high-grade peripheral and facial arteriovenous malformations

BACKGROUND

Arteriovenous malformations (AVMs) are developmental defects in the vascular system with abnormal connections between arteries and veins. A minority of AVMs are characterized by aggressive growth and continue to proliferate despite maximal surgical and interventional therapy. We report our outcomes with the use of thalidomide as the only UK specialist center adopting this novel approach for the management of AVMs refractory to conventional therapy.

METHODS

This was a retrospective case series which included only complex and proliferative AVM lesions (Schobinger grade III and IV). All patients prescribed thalidomide on a compassionate basis between September 2006 and August 2022 after attempts at embolosclerotherapy without satisfactory response were reviewed.

RESULTS

Eleven patients were included in our study. The median total duration of thalidomide use was 10 months. Two thirds of patients with pain (six of nine) reported an improvement, three quarters reported a reduction in swelling (six of eight) and all who presented with bleeding reported improvement in overall volume or frequency (four of four). Over the study period, 45% achieved a non-proliferative state with no further target vessel demonstrable on angiography. Mild, tolerable side effects such as fatigue were common (73%). There was only one major adverse reaction (neutropenia) necessitating cessation of therapy.

CONCLUSIONS

We can conclude that thalidomide is able to reduce the symptom burden for patients with complex and proliferative AVMs that were refractory to established treatment modalities. Adverse effects are common, but the benefit achieved from taking thalidomide in otherwise treatment resistant cases outweighs the risks, most of which are manageable.

Lack of association between the VEGFA gene polymorphisms and preterm birth in Korean women

Preterm birth (PTB), a pregnancy-related disease, is defined as a birth before 37 weeks of gestation. It is a major cause of maternal mortality and morbidity worldwide, and its incidence rate is steadily increasing. Various genetic factors can contribute to the etiology of PTB. Vascular endothelial growth factor A (VEGFA) gene is an important angiogenic gene and its polymorphisms have been reported to be associated with PTB development. Therefore, we conducted a case-control study to evaluate the association between VEGFA rs699947, rs2010963, and rs3025039 polymorphisms and PTB in Korean women. A total of 271 subjects (116 patients with PTB and 155 women at ≥38 weeks of gestation) were analyzed in this study. The genotyping of VEGFA gene polymorphisms was performed using polymerase chain reaction- restriction fragment length polymorphism. No significant association between the patients with PTB and the control groups was confirmed. In the combination analysis, we found a significant association between PTB and VEGFA rs699947 CC-rs2010963 GG-rs3025039 CC combination (odds ratio, 3.77; 95% confidence interval, 1.091 to 13.032; p = 0.031). The VEGFA rs699947, rs2010963, and rs3025039 polymorphisms might have no genetic association with the pathogenesis of PTB in Korean women. However, the combination analysis indicates the possibility that VEGFA acts in PTB pathophysiology. Therefore, larger sample sets and replication studies are required to further elucidate our findings.

The Role of TGF-β Signaling in Saphenous Vein Graft Failure after Peripheral Arterial Disease Bypass Surgery

Saphenous vein bypass grafting is an effective technique used to treat peripheral arterial disease (PAD). However, restenosis is the major clinical challenge for the graft vessel among people with PAD postoperation. We hypothesize that there is a common culprit behind arterial occlusion and graft restenosis. To investigate this hypothesis, we found TGF-β, a gene specifically upregulated in PAD arteries, by bioinformatics analysis. TGF-β has a wide range of biological activities and plays an important role in vascular remodeling. We discuss the molecular pathway of TGF-β and elucidate its mechanism in vascular remodeling and intimal hyperplasia, including EMT, extracellular matrix deposition, and fibrosis, which are the important pathways contributing to stenosis. Additionally, we present a case report of a patient with graft restenosis linked to the TGF-β pathway. Finally, we discuss the potential applications of targeting the TGF-β pathway in the clinic to improve the long-term patency of vein grafts.

Occurrence of Rhabdomyosarcoma After Surgery Combined with oral Sirolimus for Mixed Vascular Malformation of the Tongue

Vascular malformation is the general term of a kind of lesions originated from lymphatic vessels and vascular tissues, which contains a variety of components called mixed vascular malformation. Rhabdomyosarcoma (RMS) is a kind of soft tissue sarcoma, originating from striated muscle cells or mesenchymal cells. RMS and vascular malformation mostly occur in children, and common in the head and neck, but their simultaneous occurrence is rare. A 9-year-old boy who was hospitalized for a second attack of combined vascular malformation: hemolymphangioma. The child experienced severe upper airway obstruction and tongue bleeding. Postoperative pathology demonstrated hemolymphangioma combined with RMS. Subsequently, he was transferred to the oncology department for chemotherapy and lately died of RMS with lung metastasis. The secondary RMS may be related to the usage of sirolimus. Because of its uncertain border, vascular malformation in the oral and maxillofacial region is difficult to completely remove by surgical resection, and local recurrence could be often observed. Due to its rapid progress and continuous bleeding, the possibility of malignant tumor should be considered and multidisciplinary comprehensive treatment should be actively taken. Besides, family history of related malignant tumors and immune function should be investigated in detail before choosing the application of oral sirolimus.

Histopathological analysis of vascular malformations

OBJECTIVE

To propose and develop a histopathological criteria to help diagnose vascular malformations.

METHODS

All patients who underwent surgical resection and had a confirmed histopathological diagnosis of vascular malformations from 01 March 2018-26 February 2020 were included. A criteria based on 10 parameters was developed to help diagnose vascular malformations. Discrepancies between clinical and histopathological diagnosis were evaluated.

RESULTS

A total of 18 cases were identified. There was a discrepancy between the clinical diagnosis and the initially reported histopathological diagnosis in 16 cases (88.9%). This was reduced to 7 (38.9%) and 6 cases (33.3%) with first and second time revised histopathological analysis using proposed criteria.

CONCLUSIONS

The discrepancy between clinical and histopathological diagnoses of vascular malformations has highlighted the requirement of an agreed criteria for histopathologists to help formulate their diagnosis. The proposed criteria may be used as a guide in addressing this and guide treatment and improve clinical practice.

The rare complication of vascular malformations of the limb after sclerotherapy: a report of 3 cases and brief literature review

BACKGROUND

Vascular malformations are common but complicated types of disease in infants, with unclear causes and lack of effective prevention. The symptoms usually do not disappear and tend to progress without medical intervention. It is extremely necessary to choose correct treatment options for different types of vascular malformations. A large number of studies have confirmed that sclerotherapy has a tendency to become the first-line treatment in near future, but it is also associated with mild or severe complications. Furthermore, to our knowledge, the serious adverse event of progressive limb necrosis has not been systematically analyzed and reported in the literature.

CASE PRESENTATION

Three cases (two females and one male) were presented who were all diagnosed as vascular malformations and were treated by several sessions of interventional sclerotherapy. Their previous medical records showed the use of several sclerosants in different sessions including Polidocanol and Bleomycin. The sign of limb necrosis did not occur during the first sclerotherapy, but after the second and third sessions. Furthermore, the short-term symptomatic treatment could improve the necrosis syndrome, but could not change the outcome of amputation.

CONCLUSION

Sclerotherapy undoubtedly tends to be the first-line treatment in near future, but the adverse reactions still remain major challenges. Awareness of progressive limb necrosis after sclerotherapy and timely management by experts in centers of experience of this complication can avoid amputation.

Benign and low-grade superficial endothelial cell neoplasms in the molecular era

Vascular tumors are the most common mesenchymal neoplasms of the skin and subcutis, and they encompass a heterogeneous group with diverse clinical, histological, and molecular features, as well as biological behavior. Over the past two decades, molecular studies have enabled the identification of pathogenic recurrent genetic alterations that can be used as additional data points to support the correct classification of these lesions. The purpose of this review is to summarize the available data related to superficially located benign and low-grade vascular neoplasms and to highlight recent molecular advances with the role of surrogate immunohistochemistry to target pathogenic proteins as diagnostic biomarkers.

Multidisciplinary coordinated care of hereditary hemorrhagic telangiectasia (Osler-Weber-Rendu disease)

Hereditary hemorrhagic telangiectasia (HHT), also known as Osler-Weber-Rendu disease, is a rare disorder with a case prevalence as high as one in 5000, causing arteriovenous malformations in multiple organ systems. HHT is familial with autosomal dominant inheritance, with genetic testing allowing confirmation of the diagnosis in asymptomatic kindreds. Common clinical manifestations are epistaxis and intestinal lesions causing anemia and requiring transfusions. Pulmonary vascular malformations predispose to ischemic stroke and brain abscess and may cause dyspnea and cardiac failure. Brain vascular malformations can cause hemorrhagic stroke and seizures. Rarely, liver arteriovenous malformations can cause hepatic failure. A form of HHT can cause juvenile polyposis syndrome and colon cancer. Specialists in multiple fields may be called to care for one or more aspects of HHT, but few are familiar with evidence-based guidelines for HHT management or see a sufficient number of patients to gain experience with the unique characteristics of the disease. Primary care physicians and specialists are often unaware of the important manifestations of HHT in multiple systems and the thresholds for their screening and appropriate management. To improve familiarity, experience, and coordinated multisystem care for patients with HHT, the Cure HHT Foundation, which advocates for patients and families with this disease, has accredited 29 centers in North America with designated specialists for the evaluation and care of patients with HHT. Team assembly and current screening and management protocols are described as a model for evidence-based, multidisciplinary care in this disease.

Efficacy and safety of foam sclerotherapy with sodium tetradecyl sulfate as preferred sclerosant of venous malformations based on experience from a single specialist center

OBJECTIVE

We have assessed the efficacy and safety of interventional therapy for venous malformations (VMs), with foam sclerotherapy as the treatment of choice according to our experience at a single specialist center.

METHODS

All the patients with VMs who had undergone interventional therapy (ie, embolo-sclerotherapy and/or open surgery) from January 1, 2015 to December 31, 2019 were identified through a prospective database. The VM types were classified according to the Puig classification. The outcome measures assessed included the efficacy and complications. The former was divided into four groups: no response, mild response, moderate response, and complete response. The complications were defined as any tissue or functional damage, distal embolization, or tissue reaction. The continuous variables were compared using the analysis of variance F test, and discrete variables were analyzed using the χ² tests. P values < .05 were considered statistically significant.

RESULTS

A total of 207 patients were included. Puig type I lesions were significantly less likely to have received foam sclerotherapy using sodium tetradecyl sulfate (STS) 3% (P ≤ .001) and more likely to have been surgically excised (P ≤ .001). At the patient's first procedure during the study period, the volumes of foam STS 3% were significantly different across all types of VM (P ≤ .001). The patients with type I VMs had received a lower volume of STS 3% compared with those with type II and III VMs. The efficacy outcome categories were significantly different across all types of VMs (P ≤ .001). Overall, only 14 patients (6.8%) had reported no improvement in efficacy, and 38 patients (18%) had not attended follow-up. Therefore, 154 patients (74.8%) had experienced some form of efficacious outcome. Ten patients (4.8%) had developed complications such as hematoma, thrombophlebitis, and ulceration. The incidence of complications differed significantly across the categories (P = .030), with more complications reported for those with type I VMs.

CONCLUSIONS

We found that intervention with foam sclerotherapy using STS 3% is clinically effective and safe for patients with VMs and was most successful for those with Puig type I and II VMs.

Early follow-up quality of life and mental health of patients with congenital vascular malformations cared for in a multi-disciplinary specialist centre

OBJECTIVE

The study aimed to evaluate the early follow-up quality of life (QoL), pain and mental health of patients with congenital vascular malformation (CVM) from a variety of treatment options.

METHODS

All patients with CVM who received care and had follow-up between February 1st 2018 and January 31st 2020 were included. The health-related QoL, pain, and mental health were assessed with RAND Health Care 36-Item Short Form Survey (SF-36), visual analogue score for pain (VAS-P) and Hospital Anxiety and Depression Scale (HADS). Paired t-test was used for all analyses. p < .05 were considered significant.

RESULTS

In total, 110 patients with a mean age of 36.9 years were included in this study. In all patients following care, significant improvement was found in the bodily pain domain of SF-36 and VAS-P (both p = .01). This was largely driven by high-flow vascular malformation patients who responded better to embolo-sclerotherapy, which revealed significant improvement in the bodily pain domain of SF-36 (p = .002) and VAS-P (p = .02). Patients who received supportive treatment only reported significant improvement in mental health (p = .004) and social functioning (p = .03) domains of SF-36. Meanwhile, patients treated with embolo-sclerotherapy reported significant improvement only in VAS-P (p = .02).

CONCLUSIONS

This study concluded that the effects of care on early follow-up QoL, pain and mental health of patients with CVM were heterogenous. Future research should therefore, include larger sample size and longer term follow-up to understand the various factors that affect the QoL and mental health of these patients, as well as the holistic approaches to manage them.

Individualized treatment of congenital vascular malformations of the tongue

BACKGROUND/OBJECTIVE

Oral malformations of the tongue are exceedingly rare. The aim of this study was to evaluate the effectiveness of individualized treatment for patients with vascular malformations of the tongue.

METHODS

This retrospective study is based on a consecutive local registry at a tertiary care Interdisciplinary Center for Vascular Anomalies. Patients with vascular malformations of the tongue were included. Indications for therapy of the vascular malformation were macroglossia with the impossibility to close the mouth, bleeding, recurrent infection and dysphagia. Size regression of the malformation (volume measurement) and symptom improvement were investigated.

RESULTS

Out of 971 consecutive patients with vascular malformations, 16 patients suffered from a vascular malformation of the tongue. Twelve patients had slow-flow malformations and 4 fast-flow malformations. Indications for interventions were bleeding (4/16, 25%), macroglossia (6/16, 37.5%), and recurrent infections (4/16, 25%). For two patients (2/16, 12.5%), there was no indication for intervention due to absence of symptoms. Four patients received sclerotherapy, 7 patients Bleomycin-electrosclerotherapy (BEST) and 3 patients embolization. Median follow-up was 16 months (IQR 7-35.5). In all patients, symptoms had decreased after two interventions at a median (IQR 1-3.75). Volume reduction of the malformation of the tongue was 13.3%(from median 27.9 cm3 to median 24.2 cm3, p = 0.0039), and even more pronounced when considering only patients with BEST (from 86 cm3 to 59.1 cm3, p = 0.001).

CONCLUSION

Symptoms of vascular malformations of the tongue are improved after a median of two interventions with significantly increased volume reduction after Bleomycin-electrosclerotherapy.

Vascular malformations: An overview of their molecular pathways, detection of mutational profiles and subsequent targets for drug therapy

Vascular malformations are anomalies in vascular development that portend a significant risk of hemorrhage, morbidity and mortality. Conventional treatments with surgery, radiosurgery and/or endovascular approaches are often insufficient for cure, thereby presenting an ongoing challenge for physicians and their patients. In the last two decades, we have learned that each type of vascular malformation harbors inherited germline and somatic mutations in two well-known cellular pathways that are also implicated in cancer biology: the PI3K/AKT/mTOR and RAS/RAF/MEK pathways. This knowledge has led to recent efforts in: (1) identifying reliable mechanisms to detect a patient's mutational burden in a minimally-invasive manner, and then (2) understand how cancer drugs that target these mutations can be repurposed for vascular malformation care. The idea of precision medicine for vascular pathologies is growing in potential and will be critical in expanding the clinician's therapeutic armamentarium.

Lauromacrogol foam injection under ultrasonic guidance for pediatric lip venous malformations

OBJECTIVE

To evaluate the efficacy and safety of lauromacrogol foam sclerotherapy in the treatment of children with lip venous malformation.

METHODS

Fifty-two children (27 males and 25 females) aged from 6 months to 17 years with lip VM who underwent lauromacrogol foam injection with ultrasonic guidance from July 2018 to December 2020 in our hospital were retrospectively recruited for this study. All the children were examined by MRI, ultrasound, blood routine and coagulation before operation. We were guided by ultrasound to locate the blood flow area (nests), injecting lauromacrogol foam to fill the venous malformation. The follow-up time was 14.31 ± 5.96 (6-24) months. Follow-up items include clinical manifestations, imaging data, efficacy and complications.

RESULTS

This group of children was treated 3-5 times, an average of 4 times/case. The total effective rate was 90.38%. Pain in 4 cases, fever in 4 cases, infection in 2 cases, ulcer in 1 case. There were no serious complications such as cardiopulmonary accident.

CONCLUSION

Ultrasound guiding foam sclerotherapy with lauromacrogol is effective and safe for children with lip venous malformation.

Protocadherin gamma C3: a new player in regulating vascular barrier function

Defects in the endothelial cell barrier accompany diverse malfunctions of the central nervous system such as neurodegenerative diseases, stroke, traumatic brain injury, and systemic diseases such as sepsis, viral and bacterial infections, and cancer. Compromised endothelial sealing leads to leaking blood vessels, followed by vasogenic edema. Brain edema as the most common complication caused by stroke and traumatic brain injury is the leading cause of death. Brain microvascular endothelial cells, together with astrocytes, pericytes, microglia, and neurons form a selective barrier, the so-called blood-brain barrier, which regulates the movement of molecules inside and outside of the brain. Mechanisms that regulate blood-brain barrier permeability in health and disease are complex and not fully understood. Several newly discovered molecules that are involved in the regulation of cellular processes in brain microvascular endothelial cells have been described in the literature in recent years. One of these molecules that are highly expressed in brain microvascular endothelial cells is protocadherin gamma C3. In this review, we discuss recent evidence that protocadherin gamma C3 is a newly identified key player involved in the regulation of vascular barrier function.

Development of hemodynamically relevant acquired arterio-venous fistulae in patients with venous malformations

BACKGROUND

Venous malformations tend to retain their slow-flow behavior, even in progressive disease or regression following therapy.

OBJECTIVE

The aim of this study is to analyze the development of acquired hemodynamic relevant arterio-venous fistulae in patients with slow-flow malformations.

METHODS

This study is a retrospective analysis based on a consecutive local registry at a tertiary care Interdisciplinary Center for Vascular Anomalies. Patients with venous malformations and development of secondary arterio-venous fistulae were included. Indications for therapy of the vascular malformation were based on patients' symptoms and complications. The following endpoints were of clinical interest and were assessed: origin of development of arteriovenous fistula, development of secondary comorbidities as a result of the vascular malformation. For analysis we focused on descriptive statistics.

RESULTS

Out of 1213 consecutive patients with vascular malformations, in 6 patients perfusion changed from slow flow to arterio-venous fast-flow patterns. Four patients developed the fistula after local trauma in the area of the malformation, the other 2 patients developed the fistula due to progression of the disease and recurrent thrombophlebitis. These 2 patients had no trauma or interventions at the time of arterio-venous fistula development.

CONCLUSIONS

Acquired arterio-venous fast-flow fistula in patients with slow flow vascular malformation is very rare and might be a result of local trauma or the progression of the disease with recurrent thrombophlebitis. Specific evidence-based treatment options for these patients do not exist.

A clinicopathological reappraisal of orbital vascular malformations and distinctive GJA4 mutation in cavernous venous malformations

Vascular anomalies are common orbital lesions, while variations in previous nomenclature might hamper robust characterization of their clinicopathological and genetic features. We reviewed and reclassified 92 orbital vascular lesions by the modified International Society for the Study of Vascular Anomalies (ISSVA) classification with reappraising clinicopathological parameters of 4 main types of vascular malformations, including orbital venous malformation 1 (OVM1, cavernous venous malformation), OVM2 (varix), OVM3 (infiltrating venous malformation), and arteriovenous malformation (AVM). GJA4, BRAF, and KRAS mutations were assessed by Sanger sequencing. There were 90 cases of vascular malformations, consisting of 60 OVM1 (67%), 13 AVM (14%), 8 OVM2 (9%), 8 OVM3 (9%), and 1 lymphatic-venous malformation (1%). The prevailing OVM1, histologically characterized by well-delineated borders and a uniform cavernous growth pattern, predominantly occurred in intraconal space (57%, P = .019) with an older median age (49 years) and female predilection (73%). OVM2, OVM3, and AVM exhibited differences in the distributions of patients' ages and lesion locations. Sizes of lesions were significantly correlated with periorbital and intraconal/extraconal locations (P < .001). OVM1 had the lowest rate of residual and recurrent diseases (3%). GJA4 mutations were identified in 75% (44/59) of OVM1 but not in OVM2/3 and AVM. No BRAF or KRAS mutations were detected. In conclusion, the modified ISSVA scheme enables meaningful classification of orbital vascular malformations by highlighting the molecular correlation between the distinct clinicopathological features and specific GJA4 mutation in OVM1, which implies OVM1 as a unique variant of venous malformation genetically akin to cutaneous and hepatic counterparts.

Transcriptional data analysis reveals the association between infantile hemangiomas and venous malformations

Background: Infantile hemangiomas (IH) and venous malformations (VM) are the most common types of vascular abnormalities that seriously affect the health of children. Although there is evidence that these two diseases share some common genetic changes, the underlying mechanisms need to be further studied.

Methods: The microarray datasets of IH (GSE127487) and VM (GSE7190) were downloaded from GEO database. Extensive bioinformatics methods were used to investigate the common differentially expressed genes (DEGs) of IH and VM, and to estimate their Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways. Trough the constructing of protein-protein interaction (PPI) network, gene models and hub genes were obtained by using Cytoscape and STRING. Finally, we analyzed the co-expression and the TF-mRNA-microRNA regulatory network of hub genes.

Results: A total of 144 common DEGs were identified between IH and VM. Functional analysis indicated their important role in cell growth, regulation of vasculature development and regulation of angiogenesis. Five hub genes (CTNNB1, IL6, CD34, IGF2, MAPK11) and two microRNA (has-miR-141-3p, has-miR-150-5p) were significantly differentially expressed between IH and normal control (p < 0.05).

Conclusion: In conclusion, our study investigated the common DEGs and molecular mechanism in IH and VM. Identified hub genes and signaling pathways can regulate both diseases simultaneously. This study provides insight into the crosstalk of IH and VM and obtains several biomarkers relevant to the diagnosis and pathophysiology of vascular abnormalities.

The onset of PI3K-related vascular malformations occurs during angiogenesis and is prevented by the AKT inhibitor miransertib

Low‐flow vascular malformations are congenital overgrowths composed of abnormal blood vessels potentially causing pain, bleeding and obstruction of different organs. These diseases are caused by oncogenic mutations in the endothelium, which result in overactivation of the PI3K/AKT pathway. Lack of robust in vivo preclinical data has prevented the development and translation into clinical trials of specific molecular therapies for these diseases. Here, we demonstrate that the Pik3ca^H1047R activating mutation in endothelial cells triggers a transcriptome rewiring that leads to enhanced cell proliferation. We describe a new reproducible preclinical in vivo model of PI3K‐driven vascular malformations using the postnatal mouse retina. We show that active angiogenesis is required for the pathogenesis of vascular malformations caused by activating Pik3ca mutations. Using this model, we demonstrate that the AKT inhibitor miransertib both prevents and induces the regression of PI3K‐driven vascular malformations. We confirmed the efficacy of miransertib in isolated human endothelial cells with genotypes spanning most of human low‐flow vascular malformations.

Orbital Vascular Anomalies: A Nomenclatorial, Etiological, and Nosologic Conundrum

PURPOSE

Vascular anomalies are a heterogeneous group of disorders that frequently present in the periorbital region. They encompass 2 broad entities: vascular tumors, which possess a proliferative endothelium, and vascular malformations, which are basically localized defects of vascular morphogenesis. The primary goal of this review was to address inaccurate or controversial terminology in the oculoplastic literature concerning orbital and periorbital vascular anomalies and to categorize these lesions in an abridged and simplified hierarchical list that adheres as much as possible to the most recent (2018) iteration for the classification of vascular lesions proposed by the International Society for the Study of Vascular Anomalies (ISSVA). The secondary goal of this review was to review and update information regarding the genetic underpinnings of vascular anomalies and the downstream signaling pathways that are subsequently affected as a result of these genetic errors.

METHODS

A literature review was conducted in PubMed, MEDLINE, PubMed Central, National Center for Biotechnology Information Bookshelf, and Embase for several related keywords including "vascular anomalies, vascular malformations, vascular tumors, and cavernous venous malformation," both with and without adding the keywords "eyelid," "orbital," and "periorbital." In addition, a detailed search was conducted for controversial or obsolete keywords like "cavernous hemangioma," "lymphangioma," and "varices," again in their systemic and orbital/periorbital context.

RESULTS

Crucial issues in the 2018 ISSVA classification regarding the proper categorization of orbital vascular anomalies, particularly venous lesions, were critically evaluated and revised, and a regional, simplified, and abridged modification of the ISSVA 2018 classification was proposed.

CONCLUSIONS

Interdisciplinary and intradisciplinary dialogue concerning orbital vascular anomalies is seriously compromised due to the lack of a unanimous agreement on terminology and the absence of a unified classification concept system. The authors recommend that oculoplastic surgeons adopt ISSVA terminology whenever technically possible and scientifically sound. However, they also propose modifying the ISSVA 2018 classification specifically to adapt to the peculiarities of vascular anomalies in the periorbital region. At present, the simplified classification proposed here is a preliminary first step towards managing patients with orbital vascular anomalies with greater diagnostic and therapeutic precision, until such time in the future when the entire genetic makeup of orbital vascular anomalies is more completely elucidated. Optimistically, this could pave the way for a more robust classification and the ultimate therapeutic cure.

Towards a better treatment of patients with vascular malformations: certified interdisciplinary centers are mandatory

BACKGROUND

Vascular anomalies are orphan diseases that occur in all age groups and range from purely aesthetic to potentially life-threatening conditions. This thesis paper outlines the typical conferring problems in patient management and possible structural solutions for a better patient treatment in the future.

METHODS

A multi-perspective author panel consisting of key stakeholders from the German Interdisciplinary Society of Vascular Anomalies and the German Society for Surgery defined problem areas and possible solutions including quality indicators as criteria for certified interdisciplinary Vascular Anomalies Centers (VAC).

RESULTS

According to the literature available, clearly defined nomenclature and nosological entities often remain unused in this field, and consented diagnostic and therapeutic evidence is rare. Expert opinions dominate and in some cases lead to disparate recommendations. Typical patient problems arise from this situation, exemplified in patient vignettes. Centralized and standardized patient treatment in interdisciplinary VAC may be a solution to this problem. These centers should agree on a set of general principles and quality indicators with an additional minimum set of structural and procedural criteria.

DISCUSSION

The present position paper outlines perspectives for implementing certified interdisciplinary VAC. There is a need for a comprehensive nomenclature, access to interdisciplinary treatment centers, more scientific evidence, and further education in this rare group of diseases.

CONCLUSION

Use of scientifically sound and patient-relevant criteria for certifying the interdisciplinary quality of VAC is expected to improve health care in Germany.

Imaging of peripheral vascular malformations - current concepts and future perspectives

Vascular Malformations belong to the spectrum of orphan diseases and can involve all segments of the vascular tree: arteries, capillaries, and veins, and similarly the lymphatic vasculature. The classification according to the International Society for the Study of Vascular Anomalies (ISSVA) is of major importance to guide proper treatment. Imaging plays a crucial role to classify vascular malformations according to their dominant vessel type, anatomical extension, and flow pattern. Several imaging concepts including color-coded Duplex ultrasound/contrast-enhanced ultrasound (CDUS/CEUS), 4D computed tomography angiography (CTA), magnetic resonance imaging (MRI) including dynamic contrast-enhanced MR-angiography (DCE-MRA), and conventional arterial and venous angiography are established in the current clinical routine. Besides the very heterogenous phenotypes of vascular malformations, molecular and genetic profiling has recently offered an advanced understanding of the pathogenesis and progression of these lesions. As distinct molecular subtypes may be suitable for targeted therapies, capturing certain patterns by means of molecular imaging could enhance non-invasive diagnostics of vascular malformations. This review provides an overview of subtype-specific imaging and established imaging modalities, as well as future perspectives of novel functional and molecular imaging approaches. We highlight recent pioneering imaging studies including thermography, positron emission tomography (PET), and multispectral optoacoustic tomography (MSOT), which have successfully targeted specific biomarkers of vascular malformations.

Cellular heterogeneity and immune microenvironment revealed by single-cell transcriptome in venous malformation and cavernous venous malformation

Venous malformation (VM) and cavernous venous malformation (CVM) are two types of vascular malformations. Even if the two diseases are similar in appearance and imaging, the distinct cellular components and signaling pathways between them might help distinguish the two from a molecular perspective. Here, we performed single-cell profiling of 35,245 cells from two VM samples and three CVM samples, with a focus on endothelial cells (ECs), smooth muscle cells (SMCs) and immune microenvironment (IME). Clustering analysis based on differential gene expression unveiled 11 specific cell types, and determined CVM had more SMCs. Re-clustering of ECs and SMCs indicated CVM was dominated by arterial components, while VM is dominated by venous components. Gene set variation analysis suggested the activation of inflammation-related pathways in VM ECs, and upregulation of myogenesis pathway in CVM SMCs. In IME analysis, immune cells were identified to accounted for nearly 30% of the total cell number, including macrophages, monocytes, NK cells, T cells and B cells. Notably, more macrophages and monocytes were discovered in VM, indicating innate immune responses might be more closely related to VM pathogenesis. In addition, angiogenesis pathway was highlighted among the significant pathways of macrophages & monocytes between CVM and VM. In VM, VEGFA was highly expressed in macrophages & monocytes, while its receptors were all abundantly present in ECs. The close interaction of VEGFA on macrophages with its receptors on ECs was also predicted by CellPhoneDB analysis. Our results document cellular composition, significant pathways, and critical IME in CVM and VM development.

Genetic Basis and Therapies for Vascular Anomalies

Vascular and lymphatic malformations represent a challenge for clinicians. The identification of inherited and somatic mutations in important signaling pathways, including the PI3K (phosphoinositide 3-kinase)/AKT (protein kinase B)/mTOR (mammalian target of rapamycin), RAS (rat sarcoma)/RAF (rapidly accelerated fibrosarcoma)/MEK (mitogen-activated protein kinase kinase)/ERK (extracellular signal-regulated kinases), HGF (hepatocyte growth factor)/c-Met (hepatocyte growth factor receptor), and VEGF (vascular endothelial growth factor) A/VEGFR (vascular endothelial growth factor receptor) 2 cascades has led to the evaluation of tailored strategies with preexisting cancer drugs that interfere with these signaling pathways. The era of theranostics has started for the treatment of vascular anomalies. Registration: URL: https://www.clinicaltrialsregister.eu; Unique identifier: 2015-001703-32.

Efficacy and safety of sirolimus in the treatment of vascular malformations: A protocol for systematic review and meta-analysis

BACKGROUND

The pathophysiologic of vascular malformations is still unclear, and the treatment of vascular malformations is a challenge. With improvement in the understanding of pathogenesis of vascular malformations, sirolimus has been a promising and effective treatment. As so far, there is absent convincing evidence to confirm the efficacy of sirolimus for vascular malformations. The purpose of this study was to evaluate the effectiveness and safety of sirolimus in the treatment of vascular malformations.

METHODS

The literatures about the management of vascular malformations with sirolimus would be searched from databases of MEDLINE, EMBASE, PubMed, Web of Science, Clinicaltrials.org., Cochrane Library, China Biology Medicine Database (CBM), Wan Fang Database, China National Knowledge Infrastructure Database (CNKI), and VIP Science Technology Periodical Database. We will search each database from inception or 1995 to August 20, 2020. Two researchers worked independently on literature selection, data extraction and quality assessment. The efficacy and safety of sirolimus in the treatment of vascular malformations were the main outcomes. Adverse events after sirolimus were evaluated as the secondary outcomes. The included studies will be analyzed by Review Manager 5.3. If the results are applicable, meta-analysis would also be performed.

RESULTS

The study will evaluate the efficacy and safety of sirolimus in the treatment of vascular malformations based on current evidence.

CONCLUSION

The conclusion of this study will provide more reliable, evidence-based data for the use of sirolimus in the treatment of vascular malformations.

PROSPERO REGISTRATION NUMBER

CRD42020167881.