Cortisol–CX3CL1 association and altered cytokine–chemokine profiles in emergency medical services personnel

Resumen

BackgroundPsychological distress may be associated with systemic immune regulation through neuroendocrine–immune pathways. Emergency medical services (EMS) personnel represent a high-demand occupational group, but their circulating cytokine and chemokine profiles and their relationship with psychological distress remain poorly characterized. This exploratory cross-sectional study examined inflammatory and physiological markers in EMS personnel compared with matched controls, with particular attention to the association between cortisol and CX3CL1 and exploratory sex-related patterns.MethodsSeventy-eight participants, including 39 EMS personnel and 39 matched controls, underwent assessment of blood pressure, plasma cortisol, cytokines, chemokines, soluble adhesion molecules, and an exploratory panel of cardiovascular-related proteins. Psychological distress, including depression, anxiety, and stress symptoms, was assessed using the Depression, Anxiety and Stress Scale-21 in EMS personnel. Plasma concentrations of inflammatory mediators were analyzed after log10 transformation using two-way analysis of variance with group and sex as fixed factors. Spearman correlation analyses were used to explore associations between cortisol and inflammatory mediators.ResultsThe EMS group showed higher systolic blood pressure and cortisol levels than the control group. The EMS group also exhibited a broad cytokine–chemokine alteration characterized by increased concentrations of several cytokines, including GM-CSF, IFN-α, IL-1α, IL-1β, IL-6, IL-10, and IL-13, and chemokines, including CCL2 and CX3CL1/fractalkine. In contrast, circulating E-selectin, P-selectin, and sICAM-1 were reduced in the EMS group. Most cytokines and chemokines formed a highly intercorrelated inflammatory cluster. However, CX3CL1 showed a more independent correlation pattern and was selectively associated with cortisol, whereas cortisol was not associated with the broader cytokine–chemokine network. This cortisol–CX3CL1 association was more evident among women. Within the EMS group, women reported higher anxiety and stress scores than men, whereas men showed higher systolic and diastolic blood pressure.ConclusionEMS personnel exhibited an altered systemic cytokine–chemokine profile together with physiological changes and exploratory sex-related patterns. The selective association between cortisol and CX3CL1 suggests that circulating CX3CL1/fractalkine may reflect a stress-sensitive chemokine and a candidate marker of neuroendocrine–immune interaction. These findings support the relevance of integrating psychological, endocrine, and immune markers to characterize biological responses to psychological distress in high-demand healthcare populations.