Microbiome and metabolome dysbiosis of the gut-lung axis in pulmonary hypertension.

Previous studies have suggested that dysbiosis of the gut microbiota is associated with the development of pulmonary hypertension (PH). In this study, we established a left pulmonary artery ligation (LPAL)-induced PH rat model due to high flow and hemodynamic stress and investigated the association between gut microbiota composition and host metabolome signatures (in both gut and lung tissues) by using multiomics and correlation analysis. The results showed that LPAL successfully induced PH, characterized by increased right ventricular systolic pressure, right ventricular hypertrophy and pulmonary vascular remodelling. Moreover, gut pathological abnormalities were observed in association with dramatic alterations in the gut microbiome and metabolome as well as the lung metabolome. The increased bacterial genus Sporobacter and decreased genera Eubacterium, Eubacteriaceae, Deltaproteobacteria and Desulfovibrio featured the altered gut microbiome in LPAL-PH versus SHAM rats. Moreover, imbalanced abundance of protective metabolites (e.g., butyrate, propionate) and pathogenic metabolites (e.g., proinflammatory mediators) were seen in the gut metabolome of LPAL-PH versus SHAM rats. In addition, the altered gut microbiome strongly correlated with the altered metabolome patterns in both the gut and lung of LPAL-PH rats. In conclusion, this study revealed significant gut dysbiosis in LPAL-PH rats, characterized by altered gut microbiota composition, in association with specific changes in gut and lung metabolome profiles. These findings enriched our understanding of the unique signature of the gut microbiome and the close association of the "gut-lung axis" in LPAL-PH induced by long-term high flow, leading to novel therapeutic, diagnostic or management paradigms for this subtype of PH.