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Introduction: Pulmonary hypertension is characterized by vasoconstriction and remodeling of pulmonary arteries, leading to right ventricular hypertrophy and failure. We have previously found upregulation of transglutaminase 2 (TG2) in the right ventricle of chronic hypoxic rats. The hypothesis of the present study was that treatment with the transglutaminase inhibitor, cystamine, would inhibit the development of pulmonary arterial remodeling, pulmonary hypertension, and right ventricular hypertrophy. Methods: Effect of cystamine on transamidase activity was investigated in tissue homogenates. Wistar rats were exposed to chronic hypoxia and treated with vehicle, cystamine (40 mg/kg/day in mini-osmotic pumps), sildenafil (25 mg/kg/day), or the combination for 2 weeks. Results: Cystamine concentration-dependently inhibited TG2 transamidase activity in liver and lung homogenates. In contrast to cystamine, sildenafil reduced right ventricular systolic pressure and hypertrophy and decreased pulmonary vascular resistance and muscularization in chronic hypoxic rats. Fibrosis in the lung tissue decreased in chronic hypoxic rats treated with cystamine. TG2 expression was similar in the right ventricle and lung tissue of drug and vehicle-treated hypoxic rats. Discussion/Conclusions: Cystamine inhibited TG2 transamidase activity, but cystamine failed to prevent pulmonary hypertension, right ventricular hypertrophy, and pulmonary arterial muscularization in the chronic hypoxic rat. [ABSTRACT FROM AUTHOR]

Abstract: The purpose of the present review is to summarize the current knowledge on PH in relation to COPD and ILD from a clinical perspective with emphasis on diagnosis, biomarkers, prevalence, impact, treatment, and practical implications. PH in COPD and ILD is associated with a poor prognosis, and is considered one of the most frequent types of PH. However, the prevalence of PH among patients with COPD and ILD is not clear. The diagnosis of PH in chronic lung disease is often established by echocardiographic screening, but definitive diagnosis requires right heart catheterization, which is not systematically performed in clinical practice. Given the large number of patients with chronic lung disease, biomarkers to preclude or increase suspicion of PH are needed. NT-proBNP may be used as a rule-out test, but biomarkers with a high specificity for PH are still required. It is not known whether specific treatment with existent drugs effective in pulmonary arterial hypertension (PAH) is beneficial in lung disease related PH. Studies investigating existing PAH drugs in animal models of lung disease related PH have indicated a positive effect, and so have case reports and open label studies. However, treatment with systemically administered pulmonary vasodilators implies the risk of worsening the ventilation–perfusion mismatch in patients with lung disease. Inhaled vasodilators may be better suited for PH in lung disease, but new treatment modalities are also required. [Copyright &y& Elsevier]

Summary: Background: Pulmonary hypertension (PH) is an important complication to interstitial lung disease (ILD). The aim of the present study was to investigate the prevalence and impact of PH on prognosis and exercise capacity in ILD patients. Methods: 212 ILD patients were screened for PH by echocardiography. Criteria for PH were either a tricuspid pressure regurgitation gradient >40 mmHg, a tricuspid annular plane systolic excursion <1.8 cm or right ventricular dilatation. If possible, PH was confirmed by right heart catheterisation. Pulmonary function tests and 6 min walk tests (6MWT) were performed. Results: 29 patients (14%) had PH, 16 (8%) had mild and 13 (6%) had severe PH (mean pulmonary artery pressure ≥ 35 mmHg). Compared to patients without PH, lung function parameters were lower in PH patients, a larger proportion had idiopathic pulmonary fibrosis (IPF) (41 vs 21%, p = 0.006), and the hazard ratio for death was 8.5 (95% CI: 4–17). After correction for lung function parameters and the presence of IPF, 6MWT was significantly lower in patients with PH compared to non-PH patients (difference ± SEM: 58 ± 22 m, p = 0.01). Conclusions: PH occurred in 14% of a cohort of patients with ILD and was associated to IPF and lower lung function parameters. Mortality was markedly higher in PH patients, and the presence of PH reduced 6MWT independently of lung function and the presence of IPF. The present results emphasize the need for intensified treatment of patients with ILD and PH. [ABSTRACT FROM AUTHOR]

Abstract: The present study addressed whether combined treatment with a phosphodiesterase type 5 inhibitor, sildenafil, and a nitric oxide donor, molsidomine, prevents development of pulmonary hypertension in chronic hypoxic rats. Two weeks of hypoxia increased right ventricular systolic pressure, and right ventricular and lung weight. Treatment with either sildenafil (10 mg/kg/day) or molsidomine (15 mg/kg/day) in drinking water reduced right ventricular systolic pressure and weight, while lung weight was unchanged. Combining sildenafil and molsidomine did not have additional effects compared to molsidomine alone. The number of muscularized pulmonary arteries with diameters below 50 μm was increased in vehicle and sildenafil-treated, but not in molsidomine-treated hypoxic rats. Acetylcholine relaxation was blunted in arteries from vehicle and molsidomine-treated, but not in sildenafil-treated rats. In conclusion, both sildenafil and molsidomine blunts pulmonary hypertension and right ventricular hypertrophy in chronic hypoxic rats, but no synergistic effects were observed. [Copyright &y& Elsevier]