The right ventricle has more resident immune cells than the left ventricle

Abstract

The right ventricle (RV) pumps deoxygenated blood from the systemic circulation to the lungs for reoxygenation. Diseases such as pulmonary hypertension, pulmonary fibrosis, and chronic obstructive pulmonary disease are associated with hypoxia that leads to an increase in pulmonary vascular resistance (PVR), resulting in RV hypertrophy and dysfunction. The RV may differ from the left ventricle (LV) in the pathobiology in response to increases in afterload and no specific therapy exists for RV dysfunction. In order to gain insight into the biology of the RV compared to the LV, and perhaps uncover potentially novel therapeutic approaches for RV dysfunction, we performed RNA‐sequencing on RV and LV tissue from rats in normal ambient conditions or subjected to hypoxia (10% O2) for two weeks. Gene ontology and pathway analysis of the RV compared to the LV revealed multiple transcriptomic differences under ambient conditions and in particular, increased expression in the RV of genes related to immune function. Immune cell profiling by flow cytometry of rat cardiac digests, analyzed as the percentage of CD45+/CD11b/c+ cells in the cell population, revealed that in both ambient conditions and hypoxia, the RV had a significantly greater percentage of double‐positive cells compared to the LV (normoxia: average % ± SEM, 8.55 ± 1.71 RV vs. 2.04 ± 0.62 LV and hypoxia: 6.59 ± 2.71 vs. 1.55 ± 0.4; P <0.005, two‐way ANOVA, n=4 rats/group). Hypoxia had no significant effect on these values (P>0.05). These data reveal that the RV has a greater number of resident immune cells compared to the LV, possibly contributing to differences in pathobiology. Further investigation may reveal immune‐related therapeutic strategies for RV disease.Support or Funding InformationSupported by Department of Defense (W81XWH‐14‐1‐0372)This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.