Vascular endothelial growth factor serum levels are elevated in patients with hereditary hemorrhagic telangiectasia

Thalidomide-induced angiopoietin 2, Notch1 and Dll4 downregulation under hypoxic condition in tissues with gastrointestinal vascular malformation and human umbilical vein endothelial cells

OBJECTIVE

To determine the pathogenesis of gastrointestinal vascular malformation (GIVM) and the mechanism of thalidomide in treating GIVM by evaluating the expression of angiopoietin 2 (Ang2), Notch1, delta-like ligand 4 (Dll4) and hypoxia inducible factor 1α (Hif-1α).

METHODS

Data of 10 patients with histology-confirmed GIVM were reviewed. Immunohistochemistry of surgically resected GIVM tissues and the adjacent mucosa of the patients and normal tissues from those who had undergone colonoscopy for health examination was performed to examine the expressions of Ang2, Notch1, Dll4 and Hif-1α. In addition, in vitro effect of thalidomide on Ang2, Notch1 and Dll4 in human umbilical vein endothelial cells (HUVEC) and on HUVEC proliferation was also investigated during normoxic and hypoxic conditions.

RESULTS

GIVM lesions presented as tortuous, dilated arterioles, venules and capillaries. Ang2, Notch1 and Dll4 showed strong immunoreactivity in the cytoplasm and nuclei of GIVM lesions but negative or weak positivity in the intestinal mucosa of the adjacent tissues and normal mucosa. Under hypoxic condition the expressions of Hif-1α, Ang2, Notch1 and Dll4 were upregulated and the tube formation was more abundant with a greater diameter of tubes. Moreover, thalidomide downregulated their expression in HUVEC and HUVEC proliferation decreased in a concentration-dependent manner under both hypoxic and normoxic conditions.

CONCLUSION

Ang2, Notch1, Dll4 and Hif-1α may play an important role in the pathogenesis of GIVM and may be potential targets of thalidomide in the treatment of the disease.

Von Willebrand factor, angiodysplasia and angiogenesis

The large multimeric glycoprotein Von Willebrand factor (VWF) is best known for its role in haemostasis; however in recent years other functions of VWF have been identified, indicating that this protein is involved in multiple vascular processes. We recently described a new role for VWF in controlling angiogenesis, which may have significant clinical implications for patients with Von Willebrand disease (VWD), a genetic or acquired condition caused by the deficiency or dysfunction of VWF. VWD can be associated with angiodysplasia, a condition of degenerative blood vessels often present in the gastrointestinal tract, linked to dysregulated angiogenesis. Angiodysplasia can cause severe intractable bleeding, often refractory to conventional VWD treatments. In this review we summarise the evidence showing that VWF controls angiogenesis, and review the angiogenic pathways which have been implicated in this process. We discuss the possible mechanisms though which VWF regulates angiopoietin-2 (Ang-2) and integrin αvβ3, leading to signalling through vascular endothelial growth factor receptor-2 (VEGFR2), one of the most potent activators of angiogenesis. We also review the evidence that links VWF with angiodysplasia, and how the newly identified function of VWF in controlling angiogenesis may pave the way for the development of novel therapies for the treatment of angiodysplasia in congenital VWD and in acquired conditions such as Heyde syndrome.

HHT diagnosis by Mid-infrared spectroscopy and artificial neural network analysis

BACKGROUND

The vascular disorder Hereditary Hemorrhagic Telangiectasia (HHT) is in general an inherited disease caused by mutations in the TGF-β/BMP receptors endoglin or ALK1 or in rare cases by mutations of the TGF-β signal transducer protein Smad4 leading to the combined syndrome of juvenile polyposis and HHT. HHT is characterized by several clinical symptoms like spontaneous and recurrent epistaxis, multiple telangiectases at sites like lips, oral cavity, fingers, nose, and visceral lesions like gastrointestinal telangiectasia, pulmonary, hepatic, cerebral or spinal arteriovenous malformations. The disease shows an inter- and intra-family variability in penetrance as well as symptoms from mild to life threatening. Penetrance is also depending on age. Diagnosis of the disease is based on the presence of some of the listed symptoms or by genetic testing. HHT diagnosis is laborious, time consuming, costly and sometimes uncertain. Not all typical symptoms may be present, especially at a younger age, and genetic testing does not always identify the disease causing mutation.

METHODS

Infrared (IR) spectroscopy was investigated as a potential alternative to the current diagnostic methods. IR-spectra were obtained by Fourier-transform Mid-IR spectroscopy from blood plasma from HHT patients and a healthy control group. Spectral data were mathematically processed and subsequently classified and analysed by artificial neural network (ANN) analyses and by visual analysis of scatter plots of the dominant principal components.

RESULTS

The analyses showed that for HHT a disease specific IR-spectrum exists that is significantly different from the control group. Furthermore, at the current stage with the here used methods, HHT can be diagnosed by Mid-IR-spectroscopy in combination with ANN analysis with a sensitivity and specificity of at least 95%. Visual analysis of PCA scatter plots revealed an inter class variation of the HHT group.

CONCLUSION

IR-spectroscopy in combination with ANN analysis can be considered to be a serious alternative diagnostic method compared to clinical and genetically based methods. Blood plasma is an ideal candidate for diagnostic purposes, it is inexpensive, easy to isolate and only minimal amounts are required. In addition, IR-spectroscopy measurement times are fast, less than one minute, and diagnosis is not based on interpretation of may be uncertain clinical data. And last but not least, the method is inexpensive.

[Bevacizumab in therapy-refractory epistaxis: case report of low-dose antibody therapy for hereditary hemorrhagic telangiectasia]

We report on the submucosal injection of bevacizumab (Avastin) at a dose of 0.3 to 3.75 mg per side in a patient with hereditary hemorrhagic telangiectasia. Application of such low doses has not been described in the literature yet. Our case report shows the positive effect of low-dose bevacizumab on therapy-refractory epistaxis. No complications were caused by the bevacizumab treatment.

A long diagnostic delay in patients with Hereditary Haemorrhagic Telangiectasia: a questionnaire-based retrospective study

Background

The difficulty in establishing a timely correct diagnosis is a relevant matter of concern for several rare diseases. Many rare-disease-affected patients suffer from considerable diagnostic delay, mainly due to their poor knowledge among healthcare professionals, insufficient disease awareness among patients’ families, and lack of promptly available diagnostic tools. Hereditary Haemorrhagic Telangiectasia (HHT) is an autosomal-dominantly inherited vascular dysplasia, affecting 1:5,000-10,000 patients. HHT is characterized by high variability of clinical manifestations, which show remarkable overlapping with several common diseases.

Aim

To perform a detailed analysis concerning the diagnostic time lag occurring in patients with HHT, defined as the time period spanning from the first clinical manifestation to the attainment of a definite, correct diagnosis.

Methods

A questionnaire was administered to the HHT patients previously recruited from 2000 and 2009. Clinical onset, first referral to a physician for disease manifestations, and first correct diagnosis of definite HHT were collected. Eventual misdiagnosis at first referral and serious complications occurring throughout the time elapsing between disease onset and definite diagnosis were also addressed.

Results

In the 233 respondents, the clinical onset of disease occurred at an age of 14.1 yrs, while the age of first referral and the age of first definite diagnosis of HHT were 29.2 yrs and 40.1 yrs, respectively. Only 88/233 patients received a correct diagnosis at first counseling. Thus, the diagnostic time lag, represented by the time elapsing from disease onset and first definite diagnosis of HHT, proved to be 25.7 yrs. Twenty-two patients suffered from severe complications during this time interval. The diagnostic delay was significantly longer (p < 0.001) in index patients (first patients who attained definite HHT diagnosis in a given family) than in non-index patients (relative of index patients). The diagnostic time lag was also significantly associated with education grade (p < 0.001).

Conclusions

Our data report for the first time a systematic inquiry of diagnostic delay in HHT showing that patients receive a definite diagnosis only after nearly three decades from disease onset. Concerted efforts are still to be made to increase awareness of this disease among both families and physicians.

Iron deficiency anemia related to hereditary hemorrhagic telangiectasia: response to treatment with bevacizumab

Hereditary hemorrhagic telangiectasia (HHT) is a rare autosomal dominant condition associated with arteriovenous malformations (AVMs) or telangiectasias of the pulmonary, gastrointestinal or hepatic circulations. The authors present a case of a 52-year-old woman with a known diagnosis of HHT who presented for evaluation of anemia. She had an extensive history of iron sucrose infusions, frequent blood transfusions and hospitalizations for anemia related to gastrointestinal bleeding and epistaxis. The patient was treated with bevacizumab at a dose of 5 mg/kg infusion every 2 weeks for 4 cycles. In the next 4 months, her hemoglobin improved to 13.7 g/dL and she did not require iron or packed red blood cell transfusions for the next 8 months. Abnormal angiogenesis primarily due to mutations in the transforming growth factor β receptor endoglin and the activin receptor-like kinases is a central contributor to the formation of AVMs in HHT. Bevacizumab is a monoclonal antibody against vascular endothelial growth factor and therefore may be a useful treatment against AVM formation in patients with HHT. The authors do caution that therapy has to be individualized as there are no randomized trials regarding its usage in patients with HHT.

A retrospective analysis of low dose, intranasal injected bevacizumab (Avastin) in hereditary haemorrhagic telangiectasia

The constantly recurring epistaxis means a great reduction of quality of life for patients with hereditary haemorrhagic telangiectasia (HHT). As yet, an ideal treatment has not been found. Vascular endothelial growth factor (VEGF) has been described as a possible new therapy. In particular, the success of submucosal doses <100 mg has not been analysed before. We injected bevacizumab (Avastin) submucosally in addition to Nd:YAG laser therapy. Doses <7.5 mg were used. To investigate the effect of these additional injections in comparison to laser therapy alone, a retrospective analysis was done. For this purpose a standardized patient questionnaire was completed, which included recording the patients' Epistaxis Severity Score (ESS) before and after the antibody treatment. Besides, patient files were analysed to collect objective data like haemoglobin levels and the number of blood transfusions needed. Data for eleven patients could be analysed. A significant improvement in the ESS resulting from additional bevacizumab therapy was observed (p < 0.01). In particular, the frequency of epistaxis (p = 0.011), duration of epistaxis (p < 0.01), severity of epistaxis (p < 0.01) and the need for acute medical treatment (p = 0.014) decreased significantly. The haemoglobin levels increased significantly (p = 0.011) and the number of blood transfusions declined. There were no side effects caused by the antibody treatment. Additional injections of a low dose of bevacizumab seem to be superior to Nd:YAG laser therapy alone. These results justify further studies.

Thalidomide stimulates vessel maturation and reduces epistaxis in individuals with hereditary hemorrhagic telangiectasia

Hereditary hemorrhagic telangiectasia (HHT) is an inherited disorder characterized by vascular malformations. Many affected individuals develop recurrent nosebleeds, which can severely affect their quality of life and are clinically difficult to treat. We report here that treatment with thalidomide reduced the severity and frequency of nosebleeds (epistaxis) in the majority of a small group of subjects with HHT tested. The blood hemoglobin levels of the treated individuals rose as a result of reduced hemorrhage and enhanced blood vessel stabilization. In mice heterozygous for a null mutation in the Eng gene (encoding endoglin), an experimental model of HHT, thalidomide treatment stimulated mural cell coverage and thus rescued vessel wall defects. Thalidomide treatment increased platelet-derived growth factor-B (PDGF-B) expression in endothelial cells and stimulated mural cell activation. The effects of thalidomide treatment were partially reversed by pharmacological or genetic interference with PDGF signaling from endothelial cells to pericytes. Biopsies of nasal epithelium from individuals with HHT treated or not with thalidomide showed that similar mechanisms may explain the effects of thalidomide treatment in humans. Our findings demonstrate the ability of thalidomide to induce vessel maturation, which may be useful as a therapeutic strategy for the treatment of vascular malformations.

Hereditary haemorrhagic telangiectasia

Hereditary haemorrhagic telangiectasia (also known as Osler-Weber-Rendu syndrome) is a relatively common, under-recognized autosomal-dominant disorder that results from multisystem vascular dysplasia. It is characterized by telangiectases and arteriovenous malformations of skin, mucosa and viscera. This article summarizes the clinical manifestations and the management of this disorder and its management. This review underscores an urgent need to conduct prospective multicentre studies to develop evidence-based management guidelines for this disease.

Effects of VEGF on phenotypic severity in children with hereditary hemorrhagic telangiectasia

The purpose of this study was to estimate vascular endothelial growth factor (VEGF) and transforming growth factor (TGF)-beta1 serum levels in children with hereditary hemorrhagic telangiectasia (HHT) type 1 and type 2 and to correlate them to the presence of arteriovenous malformations (AVMs). High VEGF levels were initially found in an infant who had been hospitalized with intestinal bleeding and suspected HHT. This case led to the evaluation of VEGF and TGF-beta1 by standard enzyme-linked immunosorbent assay in 13 children with HHT and familiarity. Patients were divided into 2 groups on the basis of the presence/absence of pulmonary AVMs. No significant difference was found for VEGF and TGF-beta1 levels in HHT patients versus controls. Among HHT patients, serum levels of VEGF in those without AVM were significantly lower than those with AVM and normal controls. No difference for TGF-beta1 levels was found in these patient subgroups. Low VEGF levels may represent a protection factor against the onset of pulmonary AVMs in HHT children. However, neither VEGF nor TGF-beta1 can be used as biochemical markers for an early diagnosis in HHT. The diagnosis of HHT still requires clinical criteria, which permitted to confirm the presence of the disease in the infant with intestinal bleeding.

Long-term complications of septal dermoplasty in patients with hereditary hemorrhagic telangiectasia

OBJECTIVE

Septal dermoplasty has been recommended as the treatment of choice for life-threatening epistaxis in patients with hereditary hemorrhagic telangiectasia. This study evaluates the complications of septal dermoplasty in the management of transfusion-dependent epistaxis.

STUDY DESIGN

Consecutive retrospective study.

SUBJECTS AND METHODS

Between 1994 and 2006, septal dermoplasty was performed on 106 consecutive patients with transfusion dependent epistaxis. Of 103 potential patients, 37 either died or were lost to follow-up, which left 66 patients for study. Data on complications and quality of life were collected on 50 (76%) of 66 patients (mean follow-up, 3.75 years) via phone interview.

RESULTS

Seventy-eight percent experienced nasal odor; 72% had nasal crusting; 58% had decreased sense of smell; 30% noted worsened sinus infection; 88% could breathe through their nose; 86% stated improved quality of life.

CONCLUSION

Septal dermoplasty remains an effective way of treating transfusion dependent epistaxis in patients with hereditary hemorrhagic telangiectasia and subjectively improves their quality of life.

Angiogenesis and vascular malformations: antiangiogenic drugs for treatment of gastrointestinal bleeding

Treatment of gastrointestinal bleeding in patients with angiodysplasias and Osler's disease (hereditary hemorrhagic teleangiectasia) is clinically challenging. Frequently, vascular malformations occur as multiple disseminated lesions, making local treatment an unfavorable choice or impossible. After local therapy, lesions often recur at other sites of the intestine. However, as there are few therapeutic alternatives, repeated endoscopic coagulations or surgical resections are still performed to prevent recurrent bleeding. Hormonal therapy has been employed for more than 50 years but has recently been shown to be ineffective. Therefore, new therapeutic strategies are required. Understanding of the pathophysiology of angiogenesis and vascular malformations has recently substantially increased. Currently, multiple inhibitors of angiogenesis are under development for treatment of malignant diseases. Experimental and clinical data suggest that antiangiogenic substances, which were originally developed for treatment of malignant diseases, may also represent long-awaited specific drugs for the treatment of vascular malformations. However, antiangiogenics display significantly different actions and side-effects. Although antiangiogenics like thalidomide seem to inhibit gastrointestinal bleeding, other substances like bevacizumab can cause mucosal bleeding. Therefore differential and cautious evaluation of this therapeutic strategy is necessary.

Angiogenesis and vascular malformations: antiangiogenic drugs for treatment of gastrointestinal bleeding

Treatment of gastrointestinal bleeding in patients with angiodysplasias and Osler's disease (hereditary hemorrhagic teleangiectasia) is clinically challenging. Frequently, vascular malformations occur as multiple disseminated lesions, making local treatment an unfavorable choice or impossible. After local therapy, lesions often recur at other sites of the intestine. However, as there are few therapeutic alternatives, repeated endoscopic coagulations or surgical resections are still performed to prevent recurrent bleeding. Hormonal therapy has been employed for more than 50 years but has recently been shown to be ineffective. Therefore, new therapeutic strategies are required. Understanding of the pathophysiology of angiogenesis and vascular malformations has recently substantially increased. Currently, multiple inhibitors of angiogenesis are under development for treatment of malignant diseases. Experimental and clinical data suggest that antiangiogenic substances, which were originally developed for treatment of malignant diseases, may also represent long-awaited specific drugs for the treatment of vascular malformations. However, antiangiogenics display significantly different actions and side-effects. Although antiangiogenics like thalidomide seem to inhibit gastrointestinal bleeding, other substances like bevacizumab can cause mucosal bleeding. Therefore differential and cautious evaluation of this therapeutic strategy is necessary.

Angiogenesis and vascular malformations: Antiangiogenic drugs for treatment of gastrointestinal bleeding

Treatment of gastrointestinal bleeding in patients with angiodysplasias and Osler’s disease (hereditary hemorrhagic telangiectasia) is clinically challenging. Frequently, vascular malformations occur as multiple disseminated lesions, making local treatment an unfavorable choice or impossible. After local therapy, lesions often recur at other sites of the intestine. However, as there are few therapeutic alternatives, repeated endoscopic coagulations or surgical resections are still performed to prevent recurrent bleeding. Hormonal therapy has been employed for more than 50 years but has recently been shown to be ineffective. Therefore, new therapeutic strategies are required. Understanding of the pathophysiology of angiogenesis and vascular malformations has recently substantially increased. Currently, multiple inhibitors of angiogenesis are under development for treatment of malignant diseases. Experimental and clinical data suggest that antiangiogenic substances, which were originally developed for treatment of malignant diseases, may also represent long-awaited specific drugs for the treatment of vascular malformations. However, antiangiogenics display significantly different actions and side-effects. Although antiangiogenics like thalidomide seem to inhibit gastrointestinal bleeding, other substances like bevacizumab can cause mucosal bleeding. Therefore differential and cautious evaluation of this therapeutic strategy is necessary.

Gastrointestinal manifestations of dermatologic disorders

The skin and the gastrointestinal tract may be affected concurrently by the same diseases. Pathogenetically, these conditions may be primarily dermatologic diseases involving the gastrointestinal (GI) tract or systemic diseases involving the skin, GI tract, and liver simultaneously. The correct diagnosis of such conditions relies on the ability of the gastroenterologist to recognize the underlying dermatologic disorder. The goal of this clinical review article is to increase gastroenterologists' awareness and understanding of some of these conditions. Case vignettes are presented and the relevant literature reviewed for epidermolysis bullosa, mastocytosis, hereditary hemorrhagic telangiectasia, and melanoma. This review focuses on increasing gastroenterologists' ability to recognize, diagnose, comprehend, and manage patients with these dermatologic conditions who have GI manifestations. Advances in molecular genetics that provide insight into the underlying pathophysiology and histopathology of these lesions are highlighted.

Pharmacological therapy of vascular malformations of the gastrointestinal tract

Vascular malformation (AVM) in the gastrointestinal tract is an uncommon, but not rare, cause of bleeding and iron deficiency anemia, especially in an aging population. While endoscopic coagulative therapy is the method of choice for controlling bleeding, a substantial number of cases require additional therapy. Adjunctive or even primary phamacotherapy may be indicated in recurrent bleeding. However, there is little evidence-based proof of efficacy for any agent. The bulk of support is derived from anecdotal reports or case series. The present review compares the outcome of AVM after no intervention, coagulative therapy or focus on pharmacological agents. Most of the literature encompasses two common AVMs, angiodysplasia and hereditary hemorrhagic telangiectasia. Similarly, the bulk of information evaluates two therapies, hormones (estrogen and progesterone) and the somatostatin analogue octreotide. Of these, the former is the only therapy evaluated in randomized trials, and the results are conflicting without clear guidelines. The latter therapy has been reported only as case reports and case series without prospective trials. In addition, other anecdotally used medications are discussed.

Vascular Endothelial Growth Factor Plasma Levels Are Significantly Elevated in Patients with Cerebral Arteriovenous Malformations

BACKGROUND

Since growth and de novo generation of cerebrovascular malformations were demonstrated, a strictly congenital model cannot be further supported as unique factor in the pathogenesis of cerebral arteriovenous malformations (AVMs). Vascular endothelial growth factor (VEGF) has previously been demonstrated to be highly expressed in AVMs by immunohistochemical methods. However, systemic VEGF levels have not been analysed previously. This study aimed to investigate VEGF plasma concentrations as a possible plasma marker for neovascularization in patients with cerebral AVMs compared to healthy controls.

METHODS

The study included 17 patients with cerebral AVMs and 40 healthy controls. VEGF plasma concentrations were measured by a specific enzyme immuno-assay.

RESULTS

VEGF plasma concentrations were significantly higher in patients with cerebral AVMs (mean 140.9 pg/ml, SD 148.5 pg/ml and median 63.0 pg/ml) compared to a healthy control group (mean 44.7 pg/ml, SD 36.4 pg/ml and median 35.0 pg/ml), p = 0.0003.

CONCLUSIONS

Our findings suggest that VEGF plasma concentrations might play a role in the pathogenesis of cerebral AVMs. Further studies are necessary and would contribute to an improved understanding of the pathogenesis of cerebral AVMs.

Epistaxis in patients with hereditary hemorrhagic teleangiectasia

Introduction. Spontaneous recurrent epistaxis is the most common clinical manifestation of hereditary hemorrhagic teleangiectasia (HHT). It occurs in more than 90% of HHT patients and is the most distressing symptom. Nasal teleangiectasias tend to increase with age both in size and number, so epistaxis is heavier and more frequent. For patients with mild to moderate disease, there are many adequate treatment options. For those with severe disease, most treatments offer just a hemorrhage-free interval. Experienced otorhinolaryngologists who treat epistaxis in these patients often use the adage "to do as little as possible for as long as possible". Management of acute epistaxis. The recommendations for the management of acute epistaxis include: compression, use of topical antifibrinolytics, laser therapy, argon plasma coagulation therapy, fibrin sealant spray or gelatin sponge soaked in adrenaline. In cases of heavy acute epistaxis, an epistaxis balloon combined with artery ligation and/or embolization is the most effective treatment. Nasal packing and electrocauterisation should be avoided to prevent further trauma to the blood vessels. Treatment of recurrent epistaxis. Management of recurrent epistaxis includes topical application of laser energy (argon, Nd: YAG, KTP/532 and diode, not CO2), argon plasma coagulation in combination with 0.1% estriol ointment, caustics, antifibrinolytics, bleomycin and sclerosing substances. Systemic estrogen-progesterone at doses used for oral contraception may eliminate bleeding in women with heavy epistaxis. Systemic antifibrinolitics (used with extreme precaution) and septal dermoplasty give good results. The only method which successfully and permanently solves the problem of severe refractory epistaxis in hereditary hemorrhagic teleangiectasia is closure of the nasal cavities. .

Review article: angiogenesis soluble factors as liver disease markers

Angiogenesis is the formation of new blood vessels from pre-existing ones; it has been studied at the molecular level in different pathologies and is currently considered a promising novel therapeutic target in cancer. Recently, the use of angiogenesis soluble factors as markers of tumour growth has been investigated. The knowledge gained has led to test their use as therapeutic agents. Additionally, angiogenesis soluble factors could be used for the follow-up of pathologies that currently require monitoring with invasive techniques, like chronic viral hepatitis or renal and haematological diseases. The different factors have been described in multiple studies. In some cases, such as hepatocellular carcinoma, a potential use as prognostic markers has been suggested.