Recent advances in pulmonary vascular disease

There have been remarkable advances in our understanding of the pathobiology of pulmonary hypertension. A region on chromosome 2 encoding bone morphogenetic receptor type 2 has been identified to underlie familial and many cases of sporadic primary pulmonary arterial hypertension. The vasoactive mediators, discovered and defined by vascular biologists, have been translated into promising treatments of human disease. Prostacyclin, endothelin receptor blockers, sildenafil, and nitric oxide have been applied therapeutically to limit, and occasionally reverse, the inexorable damage to the pulmonary circulation initiated by recently identified genetic and environmental triggers of pulmonary arterial hypertension.

Eisenmenger syndrome and atrial septal defect: nature or nurture?

BACKGROUND

It has long been debated whether patients with atrial septal defect (ASD) Eisenmenger syndrome have idiopathic pulmonary arterial hypertension with an incidental ASD or severe pulmonary hypertension on the basis of their ASD shunt magnitude alone.

HYPOTHESIS

It was hypothesized that if ASD Eisenmenger patients had idiopathic pulmonary arterial hypertension with an incidental ASD, a mutation in the bone morphogenetic protein receptor-2 (BMPR2) would be found in some of these patients.

PATIENTS AND METHODS

All adult patients with ASD Eisenmenger syndrome were identified from the databases of two adult congenital cardiac units, and were matched to a control group with similar types of ASDs and no pulmonary hypertension. Gene coding for BMPR2 was examined for mutation using denaturing high-performance liquid chromatography of the entire coding sequence.

RESULTS

Eighteen adult patients with ASD Eisenmenger syndrome and 18 control patients were identified. ASD Eisenmenger patients had significantly larger ASDs than the control patients (3.7+/-1.2 cm versus 1.9+/-0.7 cm, P<0.01). A mutation in BMPR2 was not detected in either group.

CONCLUSION

ASD Eisenmenger syndrome may occur without BMPR2 mutation. Whether shunt magnitude alone or in combination with yet another genetic mutation is responsible for the development of pulmonary hypertension in these patients remains to be determined.

Opitz trigonocephaly syndrome

We report on a patient with Opitz trigonocephaly syndrome. The girl was the first-born child of consanguineous parents and had trigonocephaly, apparent hypertelorism, upslanted palpebral fissures, strabismus, small nose with broad root, abnormally modeled ears, high palate, short neck with loose skin, polysyndactyly, and prominent clitoris and labia majora. In addition, a complex cardiovascular defect (Eisenmenger disease) was observed. The patient was mentally retarded.

Expression of TGF-beta1 and its receptor genes (TbetaR I, TbetaR II, and TbetaR III-betaglycan) in peripheral blood leucocytes in patients with idiopathic pulmonary arterial hypertension and Eisenmenger's syndrome

Idiopathic pulmonary arterial hypertension (IPAH) is characterized by smooth muscle cell, endothelial cell, and fibroblast hypertrophy and an increase in extracellular matrix volume in pulmonary precapillary arterioles. These features lead to a gradual increase of pulmonary vascular resistance, right-heart failure, and premature death. Bone morphogenetic protein receptor type 2 (BMPR-2) gene mutations have been identified to cause IPAH. BMPR-2 receptor mutation results in BMP signalling pathway termination and leads to disturbed growth and differentiation of pulmonary circulation cells. Transforming growth factor (TGF)-beta1 inhibits the migration and proliferation of endothelial and smooth muscle cells, and stimulates their differentiation, thus it has antiinflammatory and immunosuppressive properties, inhibiting vascular remodeling and is responsible for extracellular matrix production. The aim of this study was to analyse the profile of TGF-beta1 and the expression of its receptor (TbetaR I, TbetaR II and TbetaR III-betaglycan) genes in IPAH and in secondary forms of pulmonary arterial hypertension [Eisenmenger's syndrome (ES) patients]. Twenty-one patients with IPAH (2 men), 12 ES patients, and 10 healthy controls were enrolled in the study. QRT-PCR analysis of the transcriptive activity of TGF-beta1 and its receptor genes was performed with each patient. There were differences in receptor gene expression among the patient groups. The highest expression was observed in Eisenmenger syndrome patients (approximately 5-to 8-fold increase). There was a negative correlation between the gene expression of TGF-beta1 and that of its receptors, and a positive correlation between TbetaR II and TbetaR III in healthy controls. In IPAH patients a positive correlation between TGF-beta1 and TbetaR I was found. There was a difference in expression of TGF-beta1/receptor gene ratios and expression of receptor gene ratios between the examined groups. The differences in expression between IPAH and ES patients might suggest the role of these cytokines in IPAH pathogenesis. A disturbed proportion of expression of TGF-beta1 and receptor genes in IPAH patients might be one of the pathogenetic factors of the disease.