Elevated Macrophage Migration Inhibitory Factor 1 Is Associated with Left and Right Ventricular Systolic Dysfunction in Heart Failure with Reduced Ejection Fraction

Background/Objectives: Low-grade systemic inflammation, characteristic of heart failure (HF), is a nonspecific inflammatory syndrome that affects the entire body. Macrophage migration inhibitory factor 1 (MIF-1) is a pro-inflammatory cytokine, a key mediator of the innate immune response, and may serve as a potential biomarker of monocyte homing and activation in HF with reduced and mildly reduced ejection fraction (HFrEF, HFmrEF). Methods: We evaluated 70 hemodynamically stable patients with left ventricular EF (LVEF) < 50% by means of echocardiography and blood sampling. Results: We report significant correlations between MIF-1, LVEF (r = −0.33, p = 0.005), LV global longitudinal strain (LVGLS, r = 0.41, p = 0.0004), and tricuspid annular plane systolic excursion (TAPSE, r = −0.37, p = 0.001). MIF-1 levels in HFrEF patients were relatively higher, but not significantly different from those observed in HFmrEF. MIF-1 showed significant associations with TAPSE to systolic pulmonary artery pressure ratio (TAPSE/sPAP, p < 0.0001). Also, patients with TAPSE/sPAP < 0.40 mm/mmHg had significantly higher levels of MIF-1 (p = 0.009). Moreover, ischemic cardiomyopathy (ICM) was more frequent in patients with MIF-1 concentrations above 520 pg/mL (57.1% MIF-1hi vs. 28.6% MIF-1lo, p = 0.029). In terms of congestion, MIF-1 showed significant associations with the presence of peripheral edema (p = 0.007), but none was found with self-reported dyspnea (p = 0.307) and New York Heart Association (NYHA) class (p = 0.486). Also, no relationship was reported with N-terminal pro-B-type natriuretic peptide concentrations (NT-proBNP, r = 0.14, p = 0.263). However, the six-minute walk distance was greater in individuals in the MIF-1lo group when compared to those in the MIF-1hi group (404.0 ± 127.4 vs. 324.8 ± 124.1 m, p = 0.010). Conclusions: Beyond identifying inflammatory biomarkers related to disease severity, linking MIF-1 to various pathophysiological mechanisms may highlight the active involvement of the monocyte-macrophage system in HF. This system holds notable significance in congestion-related conditions, acting as a major source of reactive oxygen species that perpetuate inflammation.