Pulmonary capillary and precapillary arteriolar bed

The pulmonary capillary and precapillary arteriolar bed is a specialized vascular compartment responsible for the exchange of gases between the atmosphere and the blood (NIH: StatPearls). It consists of precapillary arterioles, which are the primary resistance vessels of the pulmonary circulation, and a dense network of capillaries that interface with the alveoli. This anatomical region is not a single molecular target but rather a physiological site where various receptors and enzymes, such as phosphodiesterase-5 and endothelin receptors, are expressed and targeted by drugs (PubMed: PMID 28652319). In diseases like pulmonary arterial hypertension, this bed undergoes pathological remodeling, including endothelial dysfunction and smooth muscle hypertrophy, which increases pulmonary vascular resistance and leads to right heart failure. Therapeutic interventions aimed at this bed focus on restoring the balance between vasoconstrictors and vasodilators to improve blood flow and oxygenation. Monitoring the health of this vascular bed often involves hemodynamic measurements like pulmonary vascular resistance and imaging techniques to assess perfusion.

Other names

Pulmonary microvasculaturePulmonary vascular bedPulmonary microcirculatory bedPulmonary microcirculation

Pharmacological agents modulate the tone and structure of this vascular bed by targeting specific molecular pathways, such as the nitric oxide-sGC-cGMP pathway, the prostacyclin pathway, and the endothelin pathway, to induce vasodilation and prevent adverse remodeling (PubMed: PMID 31433719).