Effects on the secretion of metabolic regulating hormones (leptin) and posttraumatic complications in blunt polytrauma patients

Introduction: Multiple traumatized patients may develop SIRS or even MODS in the posttraumatic course. Likewise, it is known that gender differences and the related hormones play a role. Both, the inflammatory and the hormonal system interact on several biochemical levels. Among the metabolic regulating hormones, leptin appears to play a pivotal role since patients surviving a septic insult display higher leptin levels. This might be dependent on the inhibiting effect of leptin on the hypothalamic-pituitary-adrenal axis. Methods: In this prospective study, we therefore investigated leptin concentrations in multiple traumatized patients (PTS>20) to determine its role in the posttraumatic course. Serum was collected over a 14-day period. Leptin concentrations were determined using ELISA. IL-6 was routinely determined using the Immulite-system. Results: Leptin levels in normal controls amounted to 3.7± 1.4 ng/ml. These levels were significantly increased in patients without complications to a maximum of I7.6±4,2 ng/ml (/><0.01). Patients with complications displayed levels of maximal 8.0±2.1 ng/ml. Furthermore, a negative correlation between the levels of leptin and IL-6 was observed (R:=0.85). Discussion: Our data reveal sustained changes of leptin in blunt trauma patients, who develop posttraumatic complications. The inverse relationship towards IL-6 levels suggests that interactions between the inflammatory and the hormonal system occur. This inverse correlation to IL-6 serum levels may be explained by an indirect inhibitory effect of IL-6 on leptin secretion. This study provides an additional indication for the interaction between posttraumatic hormonal and immunological changes.