The pattern of preformed cytokines in tissues frequently affected by blunt trauma

Abstract

The aim of this prospective study was to determine the local concentrations of inflammatory mediators in various tissue types frequently affected by trauma to estimate the role of prestored cytokine release by mechanical tissue trauma in the induction of a systemic inflammatory response syndrome. The degree of tissue damage, evaluated by its systemic release of inflammatory mediators, represents an important factor concerning the outcome of trauma patients. Clinical trials indicate that the kind of traumatized tissue influences the cytokine pattern measured in patients blood afterwards. However, the tissue-specific mediator composition underlying this systemic mediator release is rarely elucidated. Upon approval of the local IRB/EC, skin, subcutaneous fat, muscle, cancellous bone, and lung tissue were obtained during standard surgical procedures. The protein-based concentrations of Interleukin (IL)-6, IL-8, IL-10, and IL-12 were determined in tissue homogenates by enzyme-linked immunoabsorbant assay (ELISA; n = 60 samples). Albumin was measured to evaluate the degree of blood contamination of tissue samples. IL-6 and IL-8 were consistently detectable in more than 95% of the tissue specimens. Lung and cancellous bone presented by far the highest concentrations of these cytokines, whereas skin, subcutaneous fat, and muscle showed significantly lower levels. IL-10 was not detectable in 88%; IL-12 could not be measured in 63% of the samples. Cytokine concentrations did not correlate with the amount of albumin measured in tissue specimens. Due to their consistent presence at the tissue level, high systemic concentrations of IL-6 and IL-8 in patients blood, seen after pulmonary trauma, long bone fractures, or soft tissue injury, may be interpreted as an overspill of local trauma mediators. This indicates their relevance in post-traumatic monitoring. Furthermore, albumin is a suitable and necessary indicator to evaluate influences of possible blood contamination in tissue samples.