The global view

Metabolomics-based mechanism exploration of pulmonary arterial hypertension pathogenesis: novel lessons from explanted human lungs

Pulmonary arterial hypertension has led to global health and social problems, but the pathogenic mechanism has not been fully elucidated. Dysregulated metabolism is closely associated with the pathogenesis of pulmonary arterial hypertension. Here, we investigated metabolic profile shifts to reveal the molecular mechanisms underlying pulmonary hypertension. Explanted lung tissues from 13 idiopathic pulmonary arterial hypertension patients, 5 pulmonary arterial hypertension associated with congenital heart disease patients, and 16 controls were collected for untargeted metabolomics analysis with liquid chromatography coupled with tandem mass spectrometry. The KEGG database and MetaboAnalyst 5.0 were used for pathway analysis. A Cox survival analysis model was applied to evaluate the predictive value of metabolites on prognosis. Protein expression levels in human and rat pulmonary arterial hypertension lungs and hypoxia-exposed human pulmonary artery smooth muscle cells were detected by Western blotting to study the molecular mechanisms. Significant differences in metabolites and metabolic pathways were identified among the pulmonary arterial hypertension subgroups and control tissues. The levels of spermine were positively correlated with the patients' cardiac output, and (2e)-2,5-dichloro-4-oxo-2-hexenedioic acid was positively correlated with the patients' serum creatinine levels. Patients with higher thymine levels had a better prognosis. Moreover, seven differential metabolites were associated with the AKT pathway. AKT pathway inactivation was confirmed in human and rat pulmonary hypertensive lungs and pulmonary artery smooth muscle cells exposed to hypoxia. Our findings provide the first metabolomics evidence for pulmonary arterial hypertension pathogenesis in human lungs and may contribute to the improvement in therapeutic strategies.

Prevalence, incidence, and survival of pulmonary arterial hypertension: A systematic review for the global burden of disease 2020 study

Pulmonary arterial hypertension (PAH) is characterized by increased resistance in the pulmonary arterioles as a result of remodeled blood vessels. We sought all available epidemiologic data on population‐based prevalence, incidence, and 1‐year survival of PAH as part of the Global Burden of Disease Study. We performed a systematic review searching Global Index Medicus (GIM) for keywords related to PAH between 1980 and 2021 and identified population‐representative sources of prevalence, incidence, and mortality for clinically diagnosed PAH. Of 6772 articles identified we found 65 with population‐level data: 17 for prevalence, 17 for incidence, and 58 reporting case fatality. Reported prevalence ranged from 0.37 cases/100,000 persons in a referral center of French children to 15 cases/100,000 persons in an Australian study. Reported incidence ranged from 0.008 cases/100,000 person‐years in Finland, to 1.4 cases/100,000 person‐years in a retrospective chart review at a clinic in Utah, United States. Reported 1‐year survival ranged from 67% to 99%. All studies with sex‐specific estimates of prevalence or incidence reported higher levels in females than males. Studies varied in their size, study design, diagnostic criteria, and sampling procedures. Reported PAH prevalence, incidence, and mortality varied by location and study. Prevalence ranged from 0.4 to 1.4 per 100,000 persons. Harmonization of methods for PAH registries would improve efforts at disease surveillance. Results of this search contribute to ongoing efforts to quantify the global burden of PAH.

Update on the Treatment of Pulmonary Arterial Hypertension

In the last decades, important advances have been made in the treatment of pulmonary arterial hypertension (PAH), a severe, progressive, incurable, and potentially fatal disease. For an adequate therapy, correct hemodynamic diagnosis and etiology classification are fundamental. Many etiologies - rheumatic disease, portal hypertension, congenital heart diseases, schistosomiasis - require specific measures, in addition to drug therapy for PAH. The specific therapy for PAH is based on medications that act on three pathophysiological pathways - prostacyclin, endothelin, and nitric oxide pathways. These drugs have multiple presentations (oral, intravenous, subcutaneous, and inhaled) and have changed the history of PAH. This review presents an overview of drug therapy strategies and different forms and peculiarities of PAH.