Endoscopic evaluation of gastrointestinal tract in patients with hereditary hemorrhagic telangiectasia and correlation with their genotypes.

PURPOSE: Hereditary hemorrhagic telangiectasia (HHT) is an autosomal-dominant vascular dysplasia characterized by telangiectases and arteriovenous malformations. Three causative genes are known: ENG (HHT-1), ACVRL1 (HHT-2), and SMAD4 (mutated in HHT in association with juvenile polyposis). Gastrointestinal bleeding is the most common symptom after epistaxis. The stomach and the duodenum are the main gastrointestinal sites of telangiectases. Our aim was to explore gastrointestinal tract of consecutive HHT patients to assess distribution, number, size, and type of telangiectases in relation to genotype. METHODS: HHT patients underwent gastroduodenoscopy, video capsule endoscopy, and colonoscopy. Molecular analysis of ENG and ACVRL1 was performed to identify the disease-causing mutation. RESULTS: Twenty-two patients (13 men; mean age: 59 ± 9 years) were analyzed: 7 with HHT-1, 13 with HHT-2, and 2 undefined. Gastrointestinal telangiectases were identified as follows: at gastroduodenoscopy in 86% of HHT-1 patients and in 77% of HHT-2 patients, at video capsule endoscopy in all HHT-1 patients and in 84% of HHT-2 patients, and at colonoscopy in 1 patient for each group. HHT-1 showed multiple telangiectases with a higher prevalence, more relevant in the duodenum. CONCLUSION: Our data demonstrate extensive involvement of the gastrointestinal tract with a more severe association in HHT-1. Gastroduodenoscopy provides significant information on gastrointestinal involvement, and video capsule endoscopy may be added in selected patients. Colonic polyps/adenomas were identified as occasional findings.

Increase of circulating endothelial cells in patients with Hereditary Hemorrhagic Telangiectasia.

Hereditary Hemorrhagic Telangiectasia (HHT) is an autosomal dominant disorder characterized by vascular malformations. The genes known to be associated with HHT include ENG (HHT1), ACVRL1 (HHT2) and SMAD4 (JPHT). It has been reported that circulating CD34(+) cell subsets repair damaged vessels. To investigate whether mobilization of these cells is present in the peripheral blood (PB) of HTT patients, we analyzed CD34(+) cells, CD34(+)VEGFR-2(+) progenitor or mature endothelial cells, and CD34(+)CD133(+)VEGFR-2(-) hematopoietic progenitor cells (HPCs). Cytofluorimetric analysis was performed in 150 HTT patients and 43 healthy subjects (CTRLs). In HTT patients, PB CD34(+) cells were significantly increased; the frequency of endothelial cells was higher (P = 0.002), while the frequency of CD34(+)CD133(+)VEGFR-2(-) HPCs was lower (P = 0.00007) than in CTRLs. Results were comparable in patients with ENG or ACVRL1 gene mutation; in patients with ENG mutation, the frequency of the cell subsets inversely correlated with the age of the patients at time of sampling (CD34(+)), disease duration (CD34(+)VEGFR-2(+)), and age at disease onset (CD34(+)CD133(+) VEGFR-2(-)). In conclusion, HHT patients show an increase of circulating endothelial cells and a decrease of HPCs. In patients with ENG mutation, the frequency of CD34(+) endothelial cells correlates with specific clinical characteristics suggesting that their active turnover characterizes the initial phase of the disease.

Efficacy and safety of thalidomide for the treatment of severe recurrent epistaxis in hereditary haemorrhagic telangiectasia: results of a non-randomised, single-centre, phase 2 study.

BACKGROUND: Hereditary haemorrhagic telangiectasia is a genetic disease that leads to multiregional angiodysplasia. Severe recurrent epistaxis is the most common presentation, frequently leading to severe anaemia. Several therapeutic approaches have been investigated, but they are mostly palliative and have had variable results. We aimed to assess the efficacy of thalidomide for the reduction of epistaxis in patients with hereditary haemorrhagic telangiectasia that is refractory to standard therapy. METHODS: We recruited patients aged 17 years or older with hereditary haemorrhagic telangiectasia who had severe recurrent epistaxis refractory to minimally invasive surgical procedures into an open-label, phase 2, non-randomised, single-centre study at IRCCS Policlinico San Matteo Foundation (Pavia, Italy). We gave patients thalidomide at a starting dose of 50 mg/day orally. If they had no response, we increased the thalidomide dose by 50 mg/day increments every 4 weeks, until a response was seen, up to a maximum dose of 200 mg/day. After patients had achieved a response, they continued treatment for 8-16 additional weeks. The primary endpoint was the efficacy of thalidomide measured as the percentage of patients who had reductions of at least one grade in the frequency, intensity, or duration of epistaxis. We followed up patients each month to assess epistaxis severity score and transfusion need, and any adverse events were reported. We included all patients who received any study drug and who participated in at least one post-baseline assessment in the primary efficacy population. The safety population consisted of all patients who received any dose of study treatment. This trial is registered with ClinicalTrials.gov, number NCT01485224. FINDINGS: Between Dec 1, 2011, and May 12, 2014, we enrolled 31 patients. Median follow-up was 15·9 months (IQR 10·1-22·3). Three (10%, 95% CI 2-26) patients had a complete response, with bleeding stopped, 28 (90%, 95% CI 74-98) patients had partial responses. Overall, all 31 (100%, 89-100) patients responded to therapy with a significant decrease in all epistaxis parameters (p<0·0001 for frequency, intensity, and duration). A response was achieved by 25 (81%) patients at 50 mg/day of thalidomide, five (16%) patients at 100 mg/day, and one (3%) patient at 150 mg/day. Patients had only non-serious, grade 1 adverse effects, the most common of which were constipation (21 patients), drowsiness (six patients), and peripheral oedema (eight patients). One patient died a month after the end of treatment, but this was not deemed to be related to treatment. INTERPRETATION: Low-dose thalidomide seems to be safe and effective for the reduction of epistaxis in patients with hereditary haemorrhagic telangiectasia. Our findings should be validated by further studies with larger patient populations, longer follow-up, and that also assess the benefit for quality of life. FUNDING: Telethon Foundation.

Hereditary Hemorrhagic Telangiectasia: Breakpoint Characterization of a Novel Large Deletion in ACVRL1 Suggests the Causing Mechanism.

Hereditary hemorrhagic telangiectasia (HHT) is an autosomal dominant vascular dysplasia. Mutations in either ENG or ACVRL1 account for around 85% of cases, and 10% are large deletions and duplications. Here we present a large novel deletion in ACVRL1 gene and its molecular characterization in a 3 generation Italian family. We employed short tandem repeats (STRs) analysis, direct sequencing, multiplex ligation-dependant probe amplification (MLPA) analysis, and 'deletion-specific' PCR methods. STRs Analysis at ENG and ACVRL1 loci suggested a positive linkage for ACVRL1. Direct sequencing of this gene did not identify any mutations, while MLPA identified a large deletion. These results were confirmed and exactly characterized with a 'deletion-specific' PCR: the deletion size is 4,594 bp and breakpoints in exon 3 and intron 8 show the presence of short direct repeats of 7 bp [GCCCCAC]. We hypothesize, as causative molecular mechanism, the replication slippage model. Understanding the fine mechanisms associated with genomic rearrangements may indicate the nonrandomness of these events, highlighting hot spots regions. The complete concordance among MLPA, STRs analysis and 'deletion-specific PCR' supports the usefulness of MLPA in HHT molecular analysis.

Argon plasma coagulation is an effective treatment for hereditary hemorrhagic telangiectasia patients with severe nosebleeds.

CONCLUSIONS: In contrast to the current trend according to which the treatment of hereditary hemorrhagic telangiectasia (HHT) epistaxis depends on clinical severity, argon plasma coagulation (APC) has also proven to be effective as a first-line procedure in patients with severe nosebleeds. Furthermore, with this approach patients are free from requirements for blood transfusions for a long time in the vast majority of cases. OBJECTIVE: The aim of this study was to test the efficacy of APC treatment as a first-line procedure in HHT patients affected by severe epistaxis. METHODS: From 1996 until 2011, 252 HHT patients were treated with APC in our clinic. We selected 26 patients with severe epistaxis for whom the need for blood transfusion had been recorded. This group of patients was asked to answer a questionnaire that aimed to evaluate the severity of epistaxis (defined by its intensity, frequency, and duration), to assess the duration of the benefit of treatment and to evaluate the number of blood transfusions required before and after treatment. RESULTS: After APC treatment, a statistically significant decrease in all epistaxis parameters was recorded and most patients did not need blood transfusions for several years after the procedure.

Bioinformatic analysis of pathogenic missense mutations of activin receptor like kinase 1 ectodomain.

Activin A receptor, type II-like kinase 1 (also called ALK1), is a serine-threonine kinase predominantly expressed on endothelial cells surface. Mutations in its ACVRL1 encoding gene (12q11-14) cause type 2 Hereditary Haemorrhagic Telangiectasia (HHT2), an autosomal dominant multisystem vascular dysplasia. The study of the structural effects of mutations is crucial to understand their pathogenic mechanism. However, while an X-ray structure of ALK1 intracellular domain has recently become available (PDB ID: 3MY0), structure determination of ALK1 ectodomain (ALK1(EC)) has been elusive so far. We here describe the building of a homology model for ALK1(EC), followed by an extensive bioinformatic analysis, based on a set of 38 methods, of the effect of missense mutations at the sequence and structural level. ALK1(EC) potential interaction mode with its ligand BMP9 was then predicted combining modelling and docking data. The calculated model of the ALK1(EC) allowed mapping and a preliminary characterization of HHT2 associated mutations. Major structural changes and loss of stability of the protein were predicted for several mutations, while others were found to interfere mainly with binding to BMP9 or other interactors, like Endoglin (CD105), whose encoding ENG gene (9q34) mutations are known to cause type 1 HHT. This study gives a preliminary insight into the potential structure of ALK1(EC) and into the structural effects of HHT2 associated mutations, which can be useful to predict the potential effect of each single mutation, to devise new biological experiments and to interpret the biological significance of new mutations, private mutations, or non-synonymous polymorphisms.