Lower microbial diversity in PAH compared to healthy controlHigher Firmicutes, Proteobacteria, and Actinobacteria and lower Bacteroidota and Spirochaetota in PAHAltered fecal metabolome in PAHTreatment of MCT rats with the calcium-sensing receptor antagonist NPS2143 (previously demonstrated to mitigate PAH severity) increased microbial diversity and reversed the fecal metabolite abnormalities. Here, CASR is linked to pulmonary arterial hypertension.