Abstract Prostacyclin is one of the bodies fundamental signalling pathways. It has long been considered principally anti-thrombotic hormone derived from the vascular endothelium. The role of non-vascular sources in prostacyclin synthesis has not been systematically evaluated, however, due to a lack of tools resulting in an underappreciation of its role in other contexts. Here we used cellspecific knockout mice and human tissues to show that lung, and other tissues, are powerful producers of prostacyclin independent of their vascular components. Instead, in mice and humans, lung prostacyclin synthesis is associated with fibroblasts. The fibroblast-derived prostaglandins enter the circulation and provide systemic anti-thrombotic protection. These observations define a new paradigm in prostacyclin biology in which fibroblast/non-vascular-derived prostacyclin works in parallel with endothelium-derived prostaglandins to control cardiovascular health and potentially a broad range of other biology. These results may explain how local diseases of the lung and elsewhere result in cardiovascular risk.

Tissue fibroblasts are a critical source of prostacyclin and anti-thrombotic protection