Abstract Introduction Cartilage intermediate layer protein 1 (CILP1) has emerged as a novel marker of right ventricular (RV) dysfunction in pulmonary hypertension (PH), although there is still little evidence on its role in different scenarios of RV pressure overload. The aim of our study was to analyze CILP1 as a biomarker of RV remodeling and PH severity, and compare it with N-terminal pro-brain natriuretic peptide (NTproBNP), in different experimental models of RV pressure overload. Methods Three different experimental models of RV pressure overload compared to a sham procedure were evaluated in 24 Yucatan pigs: chronic postcapillary PH by pulmonary vein banding (M1, n=6); chronic PH by aorto-pulmonary shunting (M2, n=6); RV pressure overload by PA banding (thus without PH) (M3, n=6); and sham procedure (M0, n=6). Animals were evaluated at 8 months after surgery by right heart catheterization, cardiac magnetic resonance (CMR), and blood/histological sampling. Levels of CILP1 and NTproBNP at the RV myocardium and blood were determined with dedicated ELISA and compared among groups by Wilcoxon test with Bonferroni correction. Associations between biomarkers and RV performance indices and pulmonary arterial pressure (PAP) were assessed with Spearman correlation test. Results M1 animals developed chronic postcapillary PH with normal left ventricular (LV) performance and RV maladaptive hypertrophy (RV fibrosis and systolic dysfunction). M2 animals developed chronic precapillary PH associated with LV dilatation and RV maladaptive hypertrophy. On contrast, M3-animals developed severe RV pressure overload (without PH) and hypertrophy but maintained normal RV systolic function. CILP1 and NTproBNP levels were moderately correlated (R=0.56, p=0.002). CILP1 levels in RV myocardium and plasma were significantly higher in M1, whereas NTproBNP plasma levels were significantly higher in M2 (Figure 1). CILP1 in plasma and RV myocardium significantly correlated with PAP, while myocardial CILP1 levels also correlated with RV extracellular volume (RV-ECV) by CMR (Figure 2). NTproBNP myocardial levels correlated with RV ejection fraction and RV-ECV and plasmatic levels correlated with PAP (Figure 2). Conclusions CILP1 levels were increased in the presence of PH and isolated RV dysfunction, whereas NTproBNP levels were increased in the model of PH, RV dysfunction and LV remodeling. Myocardial levels of both peptides correlated with diffuse fibrosis, estimated by CMR, whereas plasmatic levels of both biomarkers correlated with PAP. This suggests that CILP1 may be a more specific marker of RV dysfunction in PH, being less dependent of LV parameters.CILP1 and NTproBNP levels among modelsCorrelation with PAP & RV remodeling