Repeated radon exposure induced ATM kinase-mediated DNA damage response and protective autophagy in mice and human bronchial epithelial cells.

OBJECTIVE: Radon ( 222 Rn) is a naturally occurring radioactive gas that has been closely linked with the development of lung cancer. In this study, we investigated the radon-induced DNA strand breaks, a critical event in lung carcinogenesis, and the corresponding DNA damage response (DDR) in mice and human bronchial epithelial (BEAS-2B) cells. METHODS: Biomarkers of DNA double-strand breaks (DSBs), DNA repair response to DSBs, ataxia-telangiectasia mutated (ATM) kinase, autophagy, and a cell apoptosis signaling pathway as well as cell-cycle arrest and the rate of apoptosis were determined in mouse lung and BEAS-2B cells after radon exposure. RESULTS: Repeated radon exposure induced DSBs indicated by the increasing expressions of γ-Histone 2AX (H2AX) protein and H2AX gene in a time and dose-dependent manner. Additionally, a panel of ATM-dependent repair cascades [i.e. non-homologous DNA end joining (NHEJ), cell-cycle arrest and the p38 mitogen activated protein kinase (p38MAPK)/Bax apoptosis signaling pathway] as well as the autophagy process were activated. Inhibition of autophagy by 3-methyladenine pre-treatment partially reversed the expression of NHEJ-related genes induced by radon exposure in BEAS-2B cells. CONCLUSIONS: The findings demonstrated that long-term exposure to radon gas induced DNA lesions in the form of DSBs and a series of ATM-dependent DDR pathways. Activation of the ATM-mediated autophagy may provide a protective and pro-survival effect on radon-induced DSBs.

Graded transthoracic contrast echocardiography after pulmonary arteriovenous malformation embolization: can chest CT be avoided in patients with a low grade shunt?

BACKGROUND: Pulmonary arteriovenous malformations (PAVMs) are direct connections between the pulmonary artery and vein, creating right-to-left shunting (RLS). Embolization is indicated to prevent complications. Guidelines recommend follow-up chest CTs to confirm persistent occlusion and embolization of all treatable PAVMs. Graded transthoracic contrast echocardiography (TTCE) after PAVM embolization may offer a reliable alternative in a subgroup of patients while preventing radiation exposure. RESEARCH QUESTION: Can TTCE predict the need for additional embolotherapy in the post-embolization population as accurately as it does in treatment-naïve population? STUDY DESIGN AND METHODS: Since 2018, follow-up after PAVM embolization at the study institution includes both TTCE and chest-CT after 6-12 months and every 3-5 years thereafter. Patients who underwent at least one follow-up TTCE and chest-CT were included. The indication for additional embolotherapy was discussed in a multidisciplinary team meeting. The primary outcome was the indication for additional embolotherapy in each RLS-grade. Additionally, the association between the RLS-grade and indication for additional embolotherapy was investigated. RESULTS: 339 patients with 412 embolization procedures were included, median time to follow-up TTCE was 7.5 months. A RLS was present in 399 post-embolization TTCEs (97%): RLS grade 1 in 93 patients (23%), grade 2 in 149 patients (36%) and grade 3 in 157 patients (38%). In patients with a RLS grade 0-1, no treatable PAVMs were found on CT. In patients with RLS grade 2-3, 22 (15%) and 72 (46%) underwent additional embolizations. INTERPRETATION: This study shows chest CT might be forgone in patients with an RLS grade 0-1 after PAVM embolization.

Cutaneous Collagenous Vasculopathy: A Retrospective Clinical and Histopathologic Analysis of 34 Cases.

BACKGROUND: Cutaneous collagenous vasculopathy (CCV) is a rare acquired microangiopathy that commonly affects middle-aged, fair-skinned individuals. It presents with telangiectatic lesions involving the lower extremities. Histologic analysis is mandatory for diagnosis. OBJECTIVES: To describe and characterize the patients diagnosed with CCV at the Mayo Clinic. METHODS: A multicenter retrospective observational analysis was performed on patients with a clinical and histological diagnosis of CCV at the Mayo Clinic in Florida, Arizona, and Rochester from January 2000 to October 2023. RESULTS: The study included 34 patients, 22 (64.7%) females. The median age at diagnosis was 52 years (range, 12-80 years). CCV lesions were found to affect the lower extremities in 29 (85.3%) patients, followed by the trunk in 14 (41.2%). Nineteen (55.9%) patients presented 1 concomitant medical condition, 8 (23.5%) 2 conditions, and 5 (14.7%) 3 or more medical conditions, such as arterial hypertension 10 (29.4%), type 2 diabetes mellitus 3 (8.8%), hyperlipidemia 3 (8.8%), cardiac disease 3 (8.8%), and hematologic malignancy 3 (8.8%). Thirty-one patients (91.2%) were taking medications, with 19 (55.9%) taking 3 or more. Pathology staining revealed periodic acid-Schiff positivity in 23 of 34 cases (67.6%), and collagen IV in 26 of 34 cases (47.1%). Treatments included pulsed dye laser 3 (8.8%) and topical sirolimus 1 (2.9%). CONCLUSIONS: CCV is an uncommon microangiopathy that affects pediatric, middle-aged, and elderly patients. It involves the lower extremities, trunk, and upper extremities. Patients often present with associated metabolic and cardiovascular conditions and are usually taking at least 1 medication. Treatment options are limited.

Hereditary haemorrhagic telangiectasias with recurrent ischemic stroke hinted by manganese deposition in the basal ganglia: a case report and literature review.

BACKGROUND: Hereditary hemorrhagic telangiectasia (HHT) is a rare autosomal dominant inherited vascular disorder that can involve multiple organs, thus can be associated with so many clinical departments that proper screening and diagnosis of HHT are needed for providing better management of both patients and their family members. CASE PRESENTATION: We present a 58-year-old female patient with recurrent paradoxical brain embolism due to HHT. She received aspirin therapy and underwent pulmonary arteriovenous malformation embolization, recovering well and discharged 3 days postoperatively. Though ischemic stroke caused by HHT-induced vascular disorders has been reported, our patient presented with both recurrent paradoxical brain embolisms and radiologic findings of bilateral globus pallidus manganese deposition at the same time, a combination rarely reported. We also review the literature on the clinical features and management of HHT for prompt diagnosis of this genetic disease behind paradoxical embolism. CONCLUSIONS: When patients with ischemic stroke, especially recurrent ischemic stroke, have combined arteriovenous malformations (AVMs) in single or multiple organs, or clues for AVMs like manganese deposition in globus pallidus, genetic diseases such as HHT may be the reason for ischemic stroke and shouldn't be missed in the evaluation of embolic sources.

53BP1 regulates the self-renewal ability of neural stem/progenitor cells through modulating mitochondrial homeostasis.

The regulation of intracellular reactive oxygen species (ROS) levels is important for maintaining the self-renewal ability of neural stem/progenitor cells (NSCs). In this study, we demonstrate that 53BP1, a DNA damage response factor known to facilitate the repair of DNA double-strand breaks, supports the maintenance of NSC stemness. ReNcell VM human NSCs with depleted 53BP1 exhibited reduced self-renewal ability compared with control NSCs, as revealed by a decrease in neurosphere size and an increase in differentiation into neural or glial cells within an NSC culture. Furthermore, 53BP1 depletion elevated cellular ROS levels, accompanied by mitochondrial abnormalities. The reduced self-renewal ability and elevated ROS levels in 53BP1-deficient NSCs were restored with the treatment of a radical scavenger, N-acetyl-l-cysteine. In addition, we investigated the functional relationship in the NSC self-renewal ability between 53BP1 and ataxia-telangiectasia mutated (ATM) or forkhead box O3a (FOXO3a), factors required for mitochondrial homeostasis, and the maintenance of NSC stemness. We found that ATM inhibition or FOXO3a deficiency, in addition to 53BP1 deficiency, did not induce further NSC stemness impairment. Collectively, our findings show that 53BP1, by cooperatively functioning with ATM and FOXO3a, supports the maintenance of NSC stemness by modulating mitochondrial homeostasis.

MicroRNA dysregulation in ataxia telangiectasia.

Introduction: Ataxia telangiectasia (AT) is a rare disorder characterized by neurodegeneration, combined immunodeficiency, a predisposition to malignancies, and high clinical variability. Profiling of microRNAs (miRNAs) may offer insights into the underlying mechanisms of complex rare human diseases, as miRNAs play a role in various biological functions including proliferation, differentiation, and DNA repair. In this study, we investigate the differential expression of miRNAs in samples from AT patients to identify miRNA patterns and analyze how these patterns are related to the disease. Methods: We enrolled 20 AT patients (mean age 17.7 ± 9.6 years old) and collected clinical and genetic data. We performed short non-coding RNA-seq analysis on peripheral blood mononuclear cells (PBMCs) and fibroblasts to compare the miRNA expression profile between AT patients and controls. Results: We observed 42 differentially expressed (DE)-miRNAs in blood samples and 26 in fibroblast samples. Among these, three DE-miRNAs, miR-342-3p, miR-30a-5p, and miR-195-5p, were further validated in additional AT samples, confirming their dysregulation. Discussion: We identified an AT-related miRNA signature in blood cells and fibroblast samples collected from a group of AT patients. We also predicted several dysregulated pathways, primarily related to cancer, immune system control, or inflammatory processes. The findings suggest that miRNAs may provide insights into the pathophysiology and tumorigenesis of AT and have the potential to serve as useful biomarkers in cancer research.

Generation of an Isogenic Hereditary Hemorrhagic Telangiectasia Model via Prime Editing in Human Induced Pluripotent Stem Cells.

Prime editing (PE) is a recently developed genome-editing technique that enables versatile editing. Despite its flexibility and potential, applying PE in human induced pluripotent stem cells (hiPSCs) has not been extensively addressed. Genetic disease models using patient-derived hiPSCs have been used to study mechanisms and drug efficacy. However, genetic differences between patient and control cells have been attributed to the inaccuracy of the disease model, highlighting the significance of isogenic hiPSC models. Hereditary hemorrhagic telangiectasia 1 (HHT1) is a genetic disorder caused by an autosomal dominant mutation in endoglin (ENG). Although previous HHT models using mice and HUVEC have been used, these models did not sufficiently elucidate the relationship between the genotype and disease phenotype in HHT, demanding more clinically relevant models that reflect human genetics. Therefore, in this study, we used PE to propose a method for establishing an isogenic hiPSC line. Clinically reported target mutation in ENG was selected, and a strategy for PE was designed. After cloning the ENGineered PE guide RNA, hiPSCs were nucleofected along with PEmax and hMLH1dn plasmids. As a result, hiPSC clones with the intended mutation were obtained, which showed no changes in pluripotency or genetic integrity. Furthermore, introducing the ENG mutation increased the expression of proangiogenic markers during endothelial organoid differentiation. Consequently, our results suggest the potential of PE as a toolkit for establishing isogenic lines, enabling disease modeling based on hiPSC-derived disease-related cells or organoids. This approach is expected to stimulate mechanistic and therapeutic studies on genetic diseases.a.

Innovations in the management of epistaxis secondary to hereditary hemorrhagic telangiectasia: our evolution to injection sclerotherapy as the treatment of choice.

Introduction: We compared the efficacy of intralesional sclerotherapy using 3% sodium tetradecyl sulfate with non-sclerotherapy-based treatments for Hereditary Hemorrhagic Telangiectasia-associated epistaxis management. Methodology: This is a retrospective study of patients who underwent surgical intervention for HHT-associated epistaxis management from 01/2010-02/2024. Patients undergoing sclerotherapy with intralesional 3% sodium tetradecyl sulfate were included in the sclerotherapy group and others undergoing conventional non-sclerotherapy-based procedures in the non-sclerotherapy group. Outcomes like breakthrough epistaxis, emergency visits, intra-op blood loss, blood transfusions, and procedure complications in the 3-month perioperative period were compared. Results: Twenty-three patients who underwent 74 intranasal procedures were identified. In the sclerotherapy group, 17 patients underwent 47 procedures. In the non-sclerotherapy group, 10 patients underwent 27 procedures. Till the 3rd post-treatment month, fewer breakthrough epistaxis episodes were observed after sclerotherapy procedures (13/47) vs. non-sclerotherapy procedures (14/27); (p = 0.037). Intraoperative blood loss was significantly lower during sclerotherapy (median: 10 ml) vs. non-sclerotherapy procedures (median: 50 ml); p < 0.001. The time interval between successive procedures was not significantly different in the sclerotherapy (median 6.5 months) vs. the non-sclerotherapy group (median 3.5 months); p = 0.13. Nasal crusting was the most common complication in the sclerotherapy group (36.9%). Two patients in each group had new onset septal perforation, none of the patients had vision loss or cerebrovascular accident. One emergency department visit was reported in the sclerotherapy group vs. 7 (in 3 patients) in the non-sclerotherapy group. Conclusions: Compared to non-sclerotherapy treatments, intralesional sclerotherapy for epistaxis in HHT is more effective in decreasing breakthrough epistaxis, and has lower intraoperative blood loss.

Rapid Remission With Upadacitinib in a Child With Refractory Crohn's Disease and ATM Mutation: A Case Report.

Managing pediatric Crohn's disease (PCD) presents challenges due to severe complications and higher biologic therapy needs. Transitioning from anti-tumor necrosis factor agents to off-label therapies adds complexity. Although upadacitinib has demonstrated efficacy and tolerability in adult inflammatory bowel disease and pediatric atopic dermatitis, there are limited data for its application in PCD. This case report delineates successful remission with upadacitinib in a child with CD refractory to infliximab, ustekinumab, adalimumab, thalidomide, and prednisone. Notably, the patient carried an ataxia telangiectasia mutated (ATM) gene mutation. These findings provide valuable evidence for PCD management and highlight the potential benefits of upadacitinib in this population.

The Role of Thalidomide and Its Analogs in the Treatment of Hereditary Hemorrhagic Telangiectasia: A Systematic Review.

Background: Hereditary hemorrhagic telangiectasia (HHT) is a disease characterized by arteriovenous malformations and telangiectases, in which the endothelium and immune system play a role in the pathophysiology. Therefore, treatments with antiangiogenic properties which are also regarded as immunomodulators were demonstrated to play an important role in treatment. This systematic review aimed to gather the accumulated information of the use of thalidomide and its analogs in the treatment of HHT. Methods: In this systematic review, publications that were published up to March 2024 and met the inclusion criteria were compiled using the keywords 'thalidomide', 'lenalidomide', 'pomalidomide', 'immunomodulatory drugs' and 'HHT' in Medline and Scholars databases. Results: A total of 53 articles were evaluated and 15 were included in the study. Thalidomide was the predominant used agent and was observed to be used in patients with ages ranging from 37 to 77 years, with doses ranging from 50 to 200 mg daily, and the mean follow-up period was observed to be 6-60 months. Assessments regarding efficacy were based on the epistaxis severity score (ESS), hemoglobin level, and transfusion independence. While thalidomide showed significant efficacy, it also had an adverse event rate of any severity of up to 85% of patients. Use of lenalidomide to control bleeding in HHT was reported in a single case report, while the use of pomalidomide was observed to be investigated in Phase 1 and Phase 2 studies in patients aged 48 to 70 years, with doses ranging from 1 to 5 mg daily for 6-24 months. This treatment was reported to provide significant improvement in hemoglobin levels and ESS. Adverse events of any severity were observed at a frequency of 60-66%. Conclusions: Antiangiogenic agents such as thalidomide, lenalidomide, and pomalidomide may be effective in managing HHT. However, further studies are needed to optimize the timing, dose, and sequence.

Molecular and Functional Cargo of Plasma-Derived Exosomes in Patients with Hereditary Hemorrhagic Telangiectasia.

Background: Hereditary Hemorrhagic Telangiectasia (HHT) is a genetic disorder leading to frequent bleeding in several organs. As HHT diagnosis is demanding and depends on clinical criteria, liquid biopsy would be beneficial. Exosomes from biofluids are nano-sized vesicles for intercellular communication. Their cargo and characteristics represent biomarkers for many diseases. Here, exosomes of HHT patients were examined regarding their biosignature. Methods: Exosomes were isolated from the plasma of 20 HHT patients and 17 healthy donors (HDs). The total exosomal protein was quantified, and specific proteins were analyzed using Western blot and antibody arrays. Human umbilical vein endothelial cells (HUVECs) co-incubated with exosomes were functionally examined via immunofluorescence, proliferation, and scratch assay. Results: The levels of the angiogenesis-regulating protein Thrombospondin-1 were significantly higher in HHT compared to HD exosomes. Among HHT, but not HD exosomes, a negative correlation between total exosomal protein and soluble Endoglin (sENG) levels was found. Other exosomal proteins (ALK1, ALK5) and the particle concentration significantly correlated with disease severity parameters (total consultations/interventions, epistaxis severity score) in HHT patients. Functionally, HUVECs were able to internalize both HD and HHT exosomes, inducing a similar change in the F-Actin structure and a reduction in migration and proliferation. Conclusions: This study provided first insights into the protein cargo and function of HHT-derived exosomes. The data indicate changes in sENG secretion via exosomes and reveal exosomal Thrombospondin-1 as a potential biomarker for HHT. Several exosomal characteristics were pointed out as potential liquid biomarkers for disease severity, revealing a possible new way of diagnosis and prognosis of HHT.

Eales' disease with secondary coats'-like reaction: a case report.

BACKGROUND: Eales' disease is an idiopathic, inflammatory condition characterized by peripheral retinal phlebitis, distal non-perfusion, and neovascularization. Coats' disease, on the other hand, is an idiopathic, retinal vasculopathy characterized by telangiectasia and yellowish exudation. Both diseases commonly affect males. Here, we report an atypical case of unilateral Eales' disease with co-existing, secondary Coats'-like reaction in a 25-year-old male exhibiting unilateral retinal telangiectasia accompanied by subtle macular edema, extensive peripheral vascular sheathing, and distal non-perfusion in the absence of clinically visible exudation. METHODS: Case report. RESULTS: A 25-year-old male presented with painless blurring of vision in the right eye for two months. Best-corrected Snellen visual acuity was 3/60 in the affected eye, with relative afferent pupillary defect observed, and 6/9 contralaterally. Anterior segment examination was unremarkable. Right eye fundoscopy showed aneurysmal telangiectasia at the macula, 360 degrees perivascular sheathing and telangiectasia of peripheral retinal vessels. There was no exudation, neovascularization, tractional membranes, vitritis, retinitis, and choroiditis. Left eye fundus was unremarkable. Optical coherence tomography of the macula revealed disorganization and thinning of the inner retinal layers with minimal intraretinal fluid. Fundus fluorescein angiography showed leakage from the aneurysms but not from the sheathed vessels, and an enlarged foveolar avascular zone. A well-defined zone of non-perfusion and retinal vascular telangiectasia with shunts was observed. Blood investigations ruled out metabolic, infectious, haematological, and autoimmune causes. Carotid Doppler showed no stenosis, and CT angiography of the brain did not show any vascular abnormalities. In view that no cause was identified, a diagnosis of Eales' disease with secondary Coats'-like reaction was made. Treatment consisted of FFA-guided laser photocoagulation to the areas of non-perfusion. Intavitreal anti-vascular endothelial growth factor injection was not done in view of poor visual prognosis. The condition and visual acuity remained stable during 18 months of follow-up. CONCLUSION: This report highlights an atypical case of Eales' disease with co-existing, secondary Coats'-like reaction.

Specifications of the ACMG/AMP variant curation guidelines for the analysis of germline ATM sequence variants.

The ClinGen Hereditary Breast, Ovarian, and Pancreatic Cancer (HBOP) Variant Curation Expert Panel (VCEP) is composed of internationally recognized experts in clinical genetics, molecular biology, and variant interpretation. This VCEP made specifications for the American College of Medical Genetics and Association for Molecular Pathology (ACMG/AMP) guidelines for the ataxia telangiectasia mutated (ATM) gene according to the ClinGen protocol. These gene-specific rules for ATM were modified from the ACMG/AMP guidelines and were tested against 33 ATM variants of various types and classifications in a pilot curation phase. The pilot revealed a majority agreement between the HBOP VCEP classifications and the ClinVar-deposited classifications. Six pilot variants had conflicting interpretations in ClinVar, and re-evaluation with the VCEP's ATM-specific rules resulted in four that were classified as benign, one as likely pathogenic, and one as a variant of uncertain significance (VUS) by the VCEP, improving the certainty of interpretations in the public domain. Overall, 28 of the 33 pilot variants were not VUS, leading to an 85% classification rate. The ClinGen-approved, modified rules demonstrated value for improved interpretation of variants in ATM.

The Latest Developments for the Treatment of Ataxia Telangiectasia: A Narrative Review.

Ataxia telangiectasia (AT), Louis-Bar syndrome, is a rare neurodegenerative disorder caused by autosomal recessive biallelic mutations within the ataxia telangiectasia mutated (ATM) gene. Currently, there are no curative therapies available for this disorder. This review provides an overview of the latest advances in treatment methods including 1- Acetyl-DL-leucine, 2- Bone Marrow Transplantation, 3- Gene Therapy, 4- Dexamethasone, and finally 5- Red Blood Cells (RBCs) as a carrier for dexamethasone (encapsulation of dexamethasone sodium phosphate into autologous erythrocytes, known as EryDex). Most of the treatments under investigation are in the early stages, except for the EryDex System. It appears that the EryDex system and N-Acetyl-DL-Leucine may hold promise as potential treatment options.

Macular telangiectasia type 2 in a patient with Down syndrome: A possible association.

Purpose: Down syndrome (DS) is one of the most prevalent genetic diseases associated with a variety of ophthalmic disorders, including reported retinal abnormalities. Macular telangiectasia type 2 (MacTel 2) is a late-onset neurodegenerative retinal disease with a substantial genetic component. We hereby describe a case of a female with DS who presented with MacTel 2, and we discuss the possible pathways associating both entities. Observation: We report the case of a 49-year-old female with a medical history of DS and hydroxychloroquine (HCQ) intake. She was referred for HCQ retinal toxicity screening. The multimodal imaging revealed a temporal perifoveal gray area with crystal deposits on multicolor fundoscopy with parafoveal outer retinal atrophy and ellipsoid zone loss with inner retinal cavitations in both eyes on the optical Coherence Tomography (OCT) B scan. The corresponding swept-source OCT angiography confirmed the presence of bilateral macular telangiectasia. Conclusion and importance: Metabolic pathways including serine/glycine and sphingolipids are incriminated in both entities' pathogenesis suggesting a possible association, hence, the importance of raising awareness of this association. More cases are likely to be found since DS patients currently have a nearly normal lifespan. Additional retinal examination of DS adults is then necessary to look for signs of MacTel 2.

Immune profiling and functional analysis of NK and T cells in ataxia telangiectasia.

Ataxia telangiectasia (AT) is a rare autosomal-recessive disorder characterized by profound neurodegeneration, combined immunodeficiency, and an increased risk for malignant diseases. Treatment options for AT are limited, and the long-term survival prognosis for patients remains grim, primarily due to the emergence of chronic respiratory pathologies, malignancies, and neurological complications. Understanding the dysregulation of the immune system in AT is fundamental for the development of novel treatment strategies. In this context, we performed a retrospective longitudinal immunemonitoring of lymphocyte subset distribution in a cohort of AT patients (n = 65). Furthermore, we performed FACS analyses of peripheral blood mononuclear cells from a subgroup of 12 AT patients to examine NK and T cells for the expression of activating and functional markers. We observed reduced levels of peripheral blood CD3+CD8+ cytotoxic T cells, CD3+CD4+ T helper cells, and CD19+ B cells, whereas the amount of CD3--CD56+ NK cells and CD3+CD56+ NKT-like cells was similar compared with age-matched controls. Notably, there was no association between the age-dependent kinetic of T-, B-, or NK-cell counts and the occurrence of malignancy in AT patients. Additionally, our results indicate an altered NK- and T-cell response to cytokine stimulation in AT with increased levels of TRAIL, FasL, and CD16 expression in NK cells, as well as an elevated activation level of T cells in AT with notably higher expression levels of IFN-γ, CD107a, TRAIL, and FasL. Together, these findings imply function alterations in AT lymphocytes, specifically in T and NK cells, shedding light on potential pathways for innovative therapies.

Molecular mechanisms and clinical manifestations of hereditary hemorrhagic telangiectasia.

INTRODUCTION: Hereditary Hemorrhagic Telangiectasia (HHT) is charactered by telangiectasia and arteriovenous malformations (AVMs). Recurrent visceral and mucocutaneous bleeding is frequently reported among HHT patients, while data on the prevalence of thrombosis remains limited. This study aims to describe the clinical manifestations and molecular biological characteristics of HHT patients. METHODS: We conducted a retrospective study at Ruijin Hospital, affiliated with Shanghai Jiao Tong University School of Medicine. A total of 24 HHT patients, observed between January 2019 and December 2023, were included. We recorded the biological, clinical, and therapeutic events, with particular attention to bleeding and thrombotic events. Gene mutation analysis and blood constituent measurements were performed. RESULTS: The prevalence of bleeding among all HHT patients was 100 %, while thrombotic events were noted in 41.70 % of cases. Hepatic arteriovenous malformations (HAVMs) were identified in six patients, pulmonary arteriovenous malformations (PAVMs) in five patients, and cerebral arteriovenous malformations (CAVMs) in one patient. For patients with thrombosis, the discontinuation rates were 23.08 % for antiplatelet therapy and 33.33 % for anticoagulant therapy due to the increased risk of bleeding. Genetic mutations related to HHT were present in 16 patients, with ACVRL1 (activin A receptor-like type 1) mutations being the most frequent at 41.67 %, followed by ENG (endoglin) mutations at 20.83 %, and GDF2 (growth differentiation factor 2) mutations at 4.17 %. The incidence of PAVMs was 75.00 % in HHT1 patients with ENG mutations and 20 % in HHT2 patients with ACVRL1 mutations, while HAVMs occurred in 0 % and 40.00 % of these groups, respectively. Patients were divided into non-AVMs and AVMs groups. Compared to normal controls, von Willebrand factor (vWF) activity was significantly increased in all HHT patients (149.10 % vs. 90.65 %, P < 0.001). In the non-AVMs group, the median level of stromal cell-derived factor-1 (SDF-1) was significantly elevated (124.31 pg/mL vs. 2413.57 pg/mL, P < 0.05), while vWF antigen levels were markedly higher in the AVMs group (165.30 % vs. 130.60 %, P = 0.021). Further grouping of HHT patients based on bleeding and thrombosis phenotypes revealed that those with thrombosis had significantly higher median percentages of schistocytes (3.50 % vs. 0 %, P = 0.002), ferritin concentrations (318.50 µg/L vs. 115.50 µg/L, P = 0.001), and lactate dehydrogenase (LDH) levels (437 U/L vs. 105 U/L, P < 0.001). There were no significant differences in the activity of vWF, protein C (PC), protein S (PS), and factor VIII (FVIII) between the two groups. CONCLUSION: This study highlighted the complex relationship between arteriovenous malformations and genetic mutations in HHT patients. A comprehensive assessment of bleeding and thrombosis risks should be conducted for each HHT patient, additionally, further clinical studies are needed to explore the risk factors for thrombosis and anticoagulant-related bleeding in HHT.

Hereditary haemorrhagic telangiectasia: A primer for the paediatrician.

Hereditary haemorrhagic telangiectasia (HHT) is an autosomal dominant condition characterised by small telangiectasias and larger multisystem arteriovenous malformations (AVMs). Common sites of AVMs include in the nose, lungs, brain and liver. These lesions are prone to rupture, leading to complications including recurrent epistaxis and significant haemorrhage. Pulmonary hypertension (PH) can also occur. This review presents an update on the genetics, clinical manifestations, management options, and screening recommendations for children with HHT.

Increasing Endoglin Deletion in Endothelial Cells Exacerbates the Severity of Brain Arteriovenous Malformation in Mouse.

Endoglin (ENG) mutation causes type 1 hereditary hemorrhagic telangiectasia (HHT1). HHT1 patients have arteriovenous malformations (AVMs) in multiple organs, including the brain. In mice, Eng deletion induced by R26RCreER or SM22αCre leads to AVM development in the brain and other organs. We hypothesized that an increase in Eng- negative ECs will enhance AVM severity. To increase EC Eng deletion, we used a codon-improved cre (icre), which is more potent in recombination of the floxed alleles than the wild-type (WT) cre. R26RCreER;Engf/f mice that have a Rosa promoter driving and tamoxifen (TM)-inducible WT cre expression globally, and PdgfbiCreER;Engf/f mice that have a Pdgfb promoter driving and TM-inducible icre expression in ECs were treated with three intra-peritoneal injections of TM (2.5 mg/25 g of body weight) to delete Eng globally or in the ECs. AAV-VEGF was stereotactically injected into the brain to induce brain focal angiogenesis and brain AVM. We found that icre caused more Eng deletion in the brain, indicated by a lower level of Eng proteins (p < 0.001) and fewer Eng-positive ECs (p = 0.01) than mice with WT cre. Mice with icre-mediated Eng deletion have more abnormal vessels (p = 0.02), CD68+ macrophages (p = 0.002), and hemorrhage (p = 0.04) and less vascular pericyte and smooth muscle coverage than mice with WT cre. In addition, arteriovenous shunts were detected in the intestines of icre mice, a phenotype that has not been detected in WT cre mice before. RNA-seq analysis showed that 8 out of the 10 top upregulated pathways identified by gene ontology (GO) analysis are related to inflammation. Therefore, the increase in Eng deletion in ECs exacerbates AVM severity, which is associated with enhanced inflammation. Strategies that can reduce Eng-negative ECs could be used to develop new therapies to reduce AVM severity for HHT1 patients.

Safety and efficacy of intralesional bleomycin for keloids and hypertrophic scars: A systematic review and meta-analysis.

BACKGROUND: Bleomycin, originally an antitumor drug, was explored as a pathological scar treatment in the mid-1990s. However, its efficacy and safety profile varies among individuals. AIMS: This study aimed to assess topical bleomycin's efficacy and safety in treating hypertrophic scars and keloids. METHODS: We reviewed randomized controlled trials (RCTs) and controlled clinical trials (CCTs) published in English, comparing intralesional bleomycin to placebos or common intralesional scar treatments. Primary outcomes included percentage change in scar improvement, pigmentation, recurrence, atrophy, pain, telangiectasia, ulceration, patient self-assessment, and observer assessment (>50%). RESULTS: Six trials met the criteria. Bleomycin significantly improved scar reduction compared to triamcinolone (p < 0.05). There was no significant difference in pigmentation (p = 0.05) and recurrence (p = 0.21) compared to other treatments. In terms of safety, bleomycin caused less skin atrophy (p < 0.01) and telangiectasia (p < 0.01) but more pain (p = 0.03) than other treatments. CONCLUSIONS: Bleomycin was more effective than TAC, 5-FU, or TAC combined with 5-FU for treating keloids and hypertrophic scars with lower skin atrophy and telangiectasia risks. However, it may cause more pain than 5-FU or TAC. Further comprehensive studies, including RCTs, are required for objective analysis.