Exaggerated Inflammation and Monocytosis Associate With Diastolic Dysfunction in Heart Failure With Preserved Ejection Fraction: Evidence of M2 Macrophage Activation in Disease Pathogenesis

•We studied monocyte phenotype and activation markers in hypertension, LVDD, and HFPEF.•Classical and alternative monocyte subset cytokines were increased in LVDD and HFPEF.•Monocyte percentage was increased in LVDD and HFPEF and correlated with LV function.•Classical monocyte number was increased in LVDD and HFPEF; alternative monocyte number was increased in HFPEF.•Culture of healthy donor monocytes with HFPEF serum promoted M2 macrophage features.

BackgroundHeart failure with preserved ejection fraction (HFPEF) is a major health problem associated with myocardial leukocyte infiltration, inflammation, and fibrosis. Monocyte and macrophage subsets play a role in HFPEF but have not been studied. We analyzed peripheral blood monocyte phenotype and plasma markers of monocyte activation in patients with HFPEF, asymptomatic LV diastolic dysfunction (aLVDD), and asymptomatic hypertension (aHTN).Methods and ResultsPeripheral blood was collected from 23 aHTN, 30 aLVDD, and 30 HFPEF patients. Peripheral cytokines of classic/pro-inflammatory (tumor necrosis factor alpha, interleukin (IL) 12, IL-6, monocyte chemoattractant protein 1, C-X-C motif chemokine 10) and alternative/anti-inflammatory monocytes (chemokine-C-C motif ligand (CCL) 17, CCL-18, soluble CD163) were increased in aLVDD and HFPEF. Peripheral blood mononuclear cells and monocytes were purified and surface-stained for CD14, CD16, CD163, and CD206. Peripheral monocyte percentage was increased in aLVDD and HFPEF and correlated with echocardiographic LVDD indices. Classic/pro-inflammatory monocyte numbers were increased in aLVDD and HFPEF, and alternative/anti-inflammatory monocyte numbers were increased in HFPEF. CD163 M2-macrophage receptor was reduced in HFPEF. Culture of healthy donor monocytes (n = 3) with HFPEF patient–derived sera (n = 6) promoted M2 macrophage features as evidenced by altered morphology and genes (CD206, IL-10).ConclusionsIncreased peripheral inflammation, monocytosis, and monocyte differentiation to anti-inflammatory/profibrotic M2 macrophages likely associate with HFPEF and its precedent asymptomatic LVDD phase.