Abstract
The aim: To investigate biomarkers of cardiac dysfunction (soluble ST2, interleukin-33, and NT-proBNP) in combatants after blast injury and compare them with patients diagnosed with chronic heart failure (HF) with preserved and mid-range left ventricular ejection fraction.
Methods: A study involved 68 combatants who had sustained blast injuries, aged over 18. The comparison group consisted of patients with chronic HF with preserved and mid-range left ventricular ejection fraction in a compensated state; the control group included 26 apparently healthy individuals. All patients underwent a comprehensive echocardiographic examination. The levels of sST2, interleukin-33, and NT-proBNP were determined by enzyme-linked immunosorbent assay (ELISA, Abcam, Cambridge, UK).
Results: Combatants showed a statistically significant increase in soluble sST2 compared to the control group (p=0.0062), which was comparable to the elevation observed in patients with HF (p=0.0930). In contrast to sST2, interleukin-33 levels were significantly lower, with the most substantial decrease observed in the combatant group. This may indicate a degree of depletion or trapping by sST2 decoy receptors in this patient cohort. A separate echocardiographic analysis was conducted. The results demonstrated that dysregulation of the ST2 pathway and reduced interleukin-33 levels were associated with increased left ventricular myocardial hypertrophy compared to the apparently healthy individuals.
Discussion of results: Stress can induce systemic inflammation and activate the sympathoadrenal system, potentially impacting the IL-33/sST2 axis and promoting remodeling. It can be hypothesized that the reduced IL-33 levels in military personnel post-injury fail to provide a sufficient cardioprotective effect against pro-hypertrophic changes. IL-33 possesses cardioprotective properties, and sST2 acts as its decoy receptor; therefore, an increase in sST2 and/or a decrease in IL-33 creates an imbalance that may contribute to fibrosis and hypertrophy. This may explain why our study did not find a statistically significant difference in echocardiographic parameters (such as the LVMI) between the combatants and patients with HF with preserved or mid-range LVEF.
Conclusions: sST2 is a sensitive biomarker of systemic inflammation, cardiac stretch, and metabolic dysregulation. In the military population, it could serve as a valuable diagnostic and prognostic tool. Further research is needed to evaluate its inclusion in the screening protocols for combatants.