Pulmonary arterial hypertension involves pro-inflammatory monocytes and plasma mediators that promote endothelial dysfunction and inflammatory responses dependent on the severity: role of SGLT2
H Muzammel, A Mroueh, S Kerth, S Amissi, J Graff, M C Antal, A Petry, A Gorlach, M Riou, V B Schini-KerthAbstract
Background
Pulmonary arterial hypertension (PAH) is a progressive cardiopulmonary disease characterized by pulmonary microvascular remodeling, endothelial dysfunction, inflammation, and oxidative stress, ultimately leading to right heart failure. Although sodium–glucose cotransporter 2 (SGLT2) inhibitors improve left-sided heart failure outcomes, their role in PAH remains unclear.
Purpose
To investigate systemic inflammation and oxidative stress in PAH by characterizing circulating monocytes and plasma-mediated effects on vascular and immune cells, and to assess the contribution of SGLT2 to these processes.
Methods
EDTA-treated blood samples were obtained from PAH patients stratified by ESC/ERS four-strata risk score (≥3, n=20; ≤2, n=22) or healthy donors (n=25). PBMCs and plasma were isolated. Pro-inflammatory cytokines were quantified by ELISA. Immune activation and function were analyzed in PBMCs from PAH patients and controls. The effects of PAH plasma were assessed in porcine pulmonary arteries, human peri-tumoral lung specimens (Strasbourg Hospital Biobank), and healthy PBMCs. Oxidative stress, glucose uptake, gene and protein expression, and immunofluorescence were evaluated.
Results
PAH plasma showed significantly increased IL-1β, IL-6, and TNF-α levels compared with controls. Exposure of pulmonary arteries to PAH plasma increased ROS production and induced expression of markers of pro-inflammatory cytokines, M1 macrophage (CD68), AT1R/NADPH oxidases/SGLT2 signaling, fibrosis, remodeling, and endothelin; all effects were prevented by N-acetylcysteine (NAC) and empagliflozin (EMPA). In healthy PBMCs, PAH plasma increased ROS (~1.8-fold) and glucose uptake (~1.7-fold), both attenuated by EMPA or SGLT2 silencing. In human lung specimens, PAH plasma upregulated markers of pro-inflammatory cytokines, M1 macrophage (CD68, CD80, CD86), AT1R/NADPH oxidases/SGLT2 signaling, fibrosis, remodeling, and endothelin, accompanied by increased SGLT2 and reduced eNOS protein expression; these changes were normalized by NAC and EMPA. SGLT2 colocalized with CD68⁺ macrophages and CD31⁺ endothelial cells. PBMCs from PAH patients exhibited increased ROS and glucose uptake correlating with clinical risk scores and reduced by EMPA, losartan, ambrisentan, or cytokine-neutralizing antibodies. These changes were associated with upregulation of markers of M1 macrophages, AT1R/NADPH oxidases/SGLT2 pathway, and cell adhesion markers, all prevented by EMPA and NAC.
Conclusions
PAH is associated with systemic immune and endothelial dysfunction driven by pro-inflammatory cytokines, endothelin-1, and angiotensin II via activation of a NADPH oxidases/SGLT2-dependent pro-oxidant pathway. SGLT2 inhibition markedly attenuates these mechanisms, supporting its therapeutic potential in PAH.