Pro-inflammatory cytokine and vascular adhesion molecule levels in manganese and lead-exposed workers

Objectives: This study aimed to develop a model of the relationship between inflammatory cytokine and/or vascular adhesion molecule levels and clinical symptoms in individuals exposed to lead (Pb), manganese (Mn) or both (Pb+Mn).Methods: The study included 104 male workers exposed to metals for different durations in a factory setting (Mn-, Pb- and Pb+Mn-exposed groups) and 76 non-exposed male workers (control group). Interleukin (IL)-6, IL-10, Tumor Necrosis Factor (TNF)-α, soluble (s)E-selectin, and Vascular Cell Adhesion protein (VCAM)-1 levels were analyzed using enzyme-linked immunosorbent assays. Mn and Pb levels were determined using inductively coupled plasma mass spectrometry.Results: Significant intergroup differences were observed in the levels of IL-6, IL-10, TNF-α, and sE-selectin (p<0.01 for all), but not VCAM-1 (p=0.298). Fatigue was the most frequent symptom in all groups (25.7%, 37.1%, and 44.1%, respectively). Other symptoms included tremor and anxiety in the Mn-exposed group (5.7%), and tremor and paresthesia in the Pb-exposed (14.7%) and Pb+Mn-exposed groups (20.6%).Conclusions: The correlation between increased biomarker levels and clinical symptoms suggests a close relationship between inflammation and neurotoxicity. This relationship not only explains the effect of the former on the latter but also provides a clinical model for the early diagnosis of neuroinflammation.