Serum Metrnl Levels in Patients with Sepsis-Induced Myocardial Injury and Their Prognostic Significance

Objective This study aimed to evaluate the serum expression levels of Metrnl, a novel secretory protein, in patients with sepsis-induced myocardial injury (SIMI) and to investigate its association with myocardial injury, inflammation, and clinical prognosis. Methods A prospective observational cohort study was conducted, enrolling 118 patients diagnosed with sepsis. Participants were stratified into the SIMI group (n = 68) and the non-SIMI group (n = 50) based on the presence of myocardial injury. Clinical data and blood samples were collected within 24 hours of admission. Serum Metrnl levels were quantified using enzyme-linked immunosorbent assay (ELISA). Statistical analyses included Spearman's correlation, multivariate linear regression, ROC curve analysis, and survival analysis (Kaplan-Meier and Cox regression). Results Serum Metrnl levels were significantly lower in the SIMI group compared to the non-SIMI group (median: 648.82 vs. 854.62 ng/mL, P = 0.001). A significant negative correlation was observed between Metrnl levels and myocardial injury biomarkers (BNP, cTnI, CK-MB, LDH) as well as inflammatory markers (IL-6, hs-CRP) (all P < 0.001), with the strongest correlations found in the SIMI group. Multivariate regression analysis further revealed that Metrnl was independently and negatively associated with hs-CRP and APACHE II scores. Metrnl demonstrated moderate predictive ability for the occurrence of SIMI (AUC = 0.681). As Metrnl levels increased (Q1→Q4), myocardial injury and inflammation markers exhibited a stepwise decrease (trend test P < 0.001). Survival analysis showed that low Metrnl levels were associated with an increased 28-day mortality rate (P = 0.037), and Cox multivariate regression confirmed Metrnl as an independent predictor of 28-day mortality. Conclusion The study found that serum Metrnl levels were significantly reduced in patients with sepsis-induced myocardial injury. The extent of this reduction was closely associated with the severity of myocardial injury and the degree of inflammation. Metrnl may serve as a potential biomarker for early detection and prognosis in SIMI, although the underlying mechanisms warrant further investigation.