Challenges and opportunities in treating inflammation associated with pulmonary hypertension.

Introduction: Inflammatory cells are present in the lungs from patients with many, if not all, forms of severe pulmonary hypertension.
Areas Covered: Historically the first inflammatory cell identified in the pulmonary vascular lesions was the mast cell. T and B lymphocytes, as well as macrophages, are present in and around the pulmonary arterioles and many patients have elevated blood levels of interleukin 1 and 6; some patients show elevated levels of leukotriene B4. An overlap between collagen-vascular disease-associated pulmonary arterial hypertension (PAH) and idiopathic PAH exists, yet only a few studies have been designed that evaluate the effect of anti-inflammatory treatments. Here we review the pertinent data that connect PAH and inflammation/autoimmune dysregulation and evaluate experimental models of severe PAH with an emphasis on the Sugen/athymic rat model of severe PAH. Expert commentary: We postulate that there are several inflammatory phenotypes and predict that there will be several anti-inflammatory treatment strategies for severe PAH.
Competing Interests: Declaration of interest This paper was funded by grants from the National Instituted of Health (grant numbers 5PO1HL014985, R01HLI22887). M Nicolls is the cofounder of Eiccose LLC, a company investigating targeting LTB4 in pulmonary hypertension. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.