Multi-detector row helical CT and reconstructions depict the complex hepatic vascular alterations typical of hereditary hemorrhagic telangiectasia.

Background: Hereditary hemorrhagic telangiectasia (HHT) is a genetic angiodysplasia affecting multiple organs. Two genes involved in the transduction of TGF-β signalling are responsible for HHT. An additional role for vascular endothelial growth factor (VEGF) has been proposed. Serum VEGF, which has been evaluated in several diseases characterized by aberrant angiogenesis, has never been measured in patients with HHT. Aims: To evaluate VEGF serum levels in HHT patients as compared to normal subjects. Materials and Methods: 32 HHT patients (age 47.7 ± 16.7 years) and a control group of 37 healthy subjects (age 48.2 ± 15.5 years) were entered in the study. Each patient underwent serum VEGF dosage using a commercial ELISA specific for the human molecule. Results: The serum level of VEGF in HHT patients was 196.3 ± 103.2 pg/ml, while it was 152.0 ± 84.1 pg/ml in the control group. Statistical analysis showed that serum VEGF was significantly higher in HHT patients than in the controls (p < 0.031). Conclusions: According to a study performed in a murine model, persistence of the activation phase of angiogenesis might be responsible for an increased production of several angiogenic factors, in particular VEGF, in HHT. Our work is the first to suggest an increased expression of VEGF in the serum of subjects with HHT in agreement with the stimulation of VEGF synthesis proposed in the murine model.

This study established a 56 % prevalence of small-bowel telangiectases in patients with HHT. This new endoscopic technique will probably change the etiological diagnosis of occult bleeding in HHT patients (which is too often attributed only to epistaxis) and may also be able to alter treatment strategies in HHT patients with gastrointestinal bleeding.

Hereditary Hemorrhagic Telangiectasia (HHT) is a rare genetic disease characterized by mutations occurring in the endoglin and ALK-1, two receptors of transforming growth factor-beta1. From a pathogenic point of view, a possible involvement of the immune system in HHT has been suggested since a mononuclear cell infiltrate was found around the area of telangiectases. Up until now, no information has been available about the role played by leukocytes in HHT and the mechanisms elicited by secretion of their mediators. However, the fact that a deficit of adaptive immunity in HHT has been reported in a companion paper in this issue will represent a great contribution to the understanding of HHT pathogenesis. The purpose of this study was to evaluate whether patients with HHT manifest also alterations in the innate immune response. Therefore, the phenotype of T, B and natural killer lymphocytes, serum immunoglobulin levels, phagocytosis and oxidative burst activity exerted by polymorphonuclear cells (PMN) and monocytes (MO) were analyzed in 22 patients. Twenty individuals demonstrated single or multiple deficits of PMN and MO functions, while the immunophenotype of lymphocytes and serum concentrations of immunoglobulins were normal. To the best of our knowledge, this is the first demonstration of a reduction in PMN and MO functions in HHT, thus suggesting a higher susceptibility to infectious complications in these patients. The relationship between innate immune deficits and T helper 1 and monocyte-derived cytokine dysfunction in HHT, as previously reported, is discussed.

Autosomal-dominant hereditary haemorrhagic telangiectasia (HHT) is a genetically heterogeneous disease caused by mutations in at least two different loci. We screened for mutations in four Italian families where segregation studies showed clear evidence of linkage to the endoglin (ENG) locus. In addition, one sporadic case and three patients with pulmonary arteriovenous malformations, belonging to small nuclear families unsuitable for linkage analysis, were included in the screening. The proband from each family was investigated using single-strand conformation polymorphism and heteroduplex analysis; potential variants were sequenced. Four novel and one previously reported mutation were detected, as well as three new polymorphisms. The novel mutations included deletions in exon 1 (patient 581/02), exon 5 (patient 780/01) and exon 7 (patient 700/01), and a C-->T229 substitution in exon 3 (patient 462/02). When analysing patient 700/01 and his affected daughter, we encountered a mutant ENG allele with two mutations--a deletion in exon 7 and a substitution in exon 12--which converts isoleucine 575 into threonine, in a non-conserved region. Both mutations were absent in the two healthy sons of the patient, while the polymorphic variant in exon 12 was present in his healthy father. These results and haplotype-segregation studies suggest that a de novo deletion had occurred in the gamete of paternal origin. For the first time the parental germline in which a de novo HHT mutation occurred has been identified.