Distinct Inflammatory Milieu in Patients With Right Heart Failure

Abstract

Background: Right heart failure (RHF) is associated with worse clinical outcomes. In addition to hemodynamic perturbations, the syndrome of RHF involves liver congestion and dysfunction. The mechanisms that underlie heart-liver interactions are poorly understood and may involve secreted factors. As a first step to understand the cardiohepatic axis, we sought to elucidate the circulating inflammatory milieu in patients with RHF.

Methods: Blood samples were collected from the inferior vena cava and hepatic veins during right heart catheterization from 3 groups of patients: (1) controls with normal cardiac function, (2) patients with heart failure who did not meet all criteria of RHF, and (3) patients who met prespecified criteria for RHF defined by hemodynamic and echocardiographic parameters. We performed a multiplex protein assay to survey levels of several circulating markers and analyzed their association with mortality and the need for a left ventricular assist device or heart transplant. Finally, we leveraged publicly available single-cell RNA sequencing data and performed tissue imaging to evaluate the expression of these factors in the liver.

Results: In this study, RHF was associated with elevated levels of a subset of cytokines/chemokines/growth factors compared with controls. In particular, soluble CD163 (cluster of differentiation 163) and CXCL12 (chemokine [C-X-C motif] ligand 12) were higher in RHF and predicted left ventricular assist device/transplant-free survival in an independent validation cohort. Furthermore, single-cell RNA sequencing and immunohistochemistry of human liver biopsies suggest that these factors are expressed by Kupffer cells and may be liver derived.

Conclusions: RHF is associated with a distinct circulating inflammatory profile. Soluble CD163 and CXCL12 are novel biomarkers that can prognosticate patient outcomes. Future studies to define how these molecules influence heart failure phenotypes and disease progression may lead to new approaches to the management of patients with RHF.

Keywords: Kupffer cells; biopsy; cytokines; heart failure; hemodynamics.

Figure 1.. Comparison of heart failure (HF) and right heart failure (RHF) patients.

(A) Distribution of patients based on hospitalization status and indication for RHC. (B) Distribution of LVEF and PVR across the control (green), HF (blue), and RHF (red) cohorts. The bars represent mean values. (C) Kaplan-Meier survival analysis of patients with HF based on presence of RHF (top), LVEF > 40% (middle), or PVR > 3 Wood Units (bottom). Log rank p-values are shown. HF= heart failure, RHF= right heart failure, PVR= pulmonary vascular resistance, RHC= right heart catheterization, LVEF = left ventricular ejection fraction

Figure 2.. Cytokine profile in control, heart failure (HF) and right heart failure (RHF) patients.

Quantification of the indicated cytokines via multiplex protein assay in control (green), HF (blue), and RHF (red) cohorts. The dots represent individual patient values, with the mean and standard deviation shown. P-values by ANOVA are shown for the indicated comparisons. HF= heart failure, RHF= right heart failure

Figure 3.. Chemokine and growth factor profile in control, heart failure (HF) and right heart failure (RHF) patients.

Quantification of the indicated chemokines and growth factors via multiple protein assay in control (green), HF (blue), and RHF (red) cohorts. The dots represent individual patient values, with the mean and standard deviation shown. P-values by ANOVA are shown for the indicated comparisons. HF= heart failure, RHF= right heart failure

Figure 4.. Soluble CD163 and CXCL12 are associated with worse outcomes.

(A) Kaplan-Meier curves for all-cause mortality, stratified by median value of soluble CD163 and CXCL12. (B) Cox proportional hazards model for death, LVAD, or transplant adjusted for soluble CD163/CXCL12, creatinine, NT-proBNP, ejection fraction, and age. The Hazard ratios, 95% confidence intervals, and p-values are shown. LVAD= left ventricular assist device

Figure 5.. Validation of soluble CD163 and CXCL12 as markers of worse outcomes in patients with heart failure.

(A) Kaplan-Meier curves for survival in the Washington University Heart Failure Registry, stratified by quartiles of soluble CD163 and CXCL12. (B) Cox proportional hazards model for transplant-free survival adjusted for soluble CD163/CXCL12, creatinine, ejection fraction, race, gender, and age. The Hazard ratios, 95% confidence intervals, and p-values are shown. RFU=relative fluorescence unit, AA=African-American

Figure 6.. Kupffer cells are impacted in congestive hepatopathy.

(A) t-SNE plot generated from single cell RNA sequencing of human liver demonstrating clusters according to cell population (left). KC are indicated by the red circle. t-SNE dot plot expression of CD163 and CXCL12 for live liver cells, highlighting their preferential expression in KC (right). (B) Representative immunohistochemistry of CD163 on liver tissue from controls (top) and those with CH (bottom). Red and blue arrows denote KC and dilated sinusoids characteristic of CH, respectively. (C) Quantification of CD163 cell number and area in controls versus CH patients. (D) Immunofluorescence imaging of CXCL12 and CD68 in liver tissue from patients with CH demonstrating significant colocalization. Low power (upper panels) and high power (lower panels) are shown. Scale bars are 50 microns. (E) Schematic representation of right heart failure impacting the release of CD163 and CXCL12 from liver KC. KC=Kupffer cells CH=congestive hepatopathy HPF=high powered field