Characteristics of interstitial fibrosis and inflammatory cell infiltration in right ventricles of systemic sclerosis-associated pulmonary arterial hypertension

Abstract

Objective. Systemic sclerosis-associated pulmonary arterial hypertension (SScPAH) has a disturbed function of the right ventricle (RV) when compared to idiopathic PAH (IPAH). Systemic sclerosis may also affect the heart. We hypothesize that RV differences may occur at the level of interstitial inflammation andfibrosis and compared inflammatory cell infiltrate and fibrosis between the RV of SScPAH, IPAH, and healthy controls. Methods. Paraffin-embedded tissue samples of RV and left ventricle (LV) from SScPAH (n = 5) and IPAH (n = 9) patients and controls (n = 4) were picrosirius red stained for detection of interstitial fibrosis, which was quantified semiautomatically. Neutrophilic granulocytes (MPO), macrophages (CD68), and lymphocytes (CD45) were immunohistochemically stained and only interstitial leukocytes were counted. Presence of epi- or endocardial inflammation, and of perivascular or intimal fibrosis of coronary arteries was assessed semiquantitatively (03: absent to extensive). Results. RV's of SScPAH showed significantly more inflammatory cells than of IPAH (cells/ mm 2, mea n ± s d MPO 11 ± 3 versus 6 ± 1; CD68 1 1 ± 3 versus 6 ± 1; CD45 1 1 ± 1 versus 5 ± 1, P