Serum Levels of Hsp 72 Measured Early after Trauma Correlate with Survival

Abstract

Experimental studies have shown that hemorrhagic shock is associated with the expression of inducible heat proteins, especially heat shock protein (Hsp) 72, in liver, brain, heart, and kidney. Moreover, induction of Hsp 72 by various stressors before the onset of shock has been associated with the attenuation of organ injury caused by hemorrhage. However, it is not known whether Hsp 72 is expressed after severe trauma in humans. The purpose of this study was therefore to determine whether Hsp 72 could be detected in the serum of patients early after severe trauma and whether serum levels of Hsp 72 might correlate with survival of trauma patients or the severity of the postinjury inflammatory response. Clinical data were collected prospectively over a 3-year period for trauma patients mechanically ventilated for more than 2 days who met the following inclusion criteria: Injury Severity Score > or = 16, and age > 18 years. Physiologic data for quantitative assessment of organ dysfunction were collected for each patient. Hsp 72 and nitrate and nitrite levels were measured in the serum of trauma patients collected at or 12 to 48 hours after the admission to the emergency department. Sixty-seven patients with severe trauma were enrolled in the study. Hsp 72 was detected in the serum of all trauma patients. All patients with high initial serum levels of Hsp 72 (serum levels > 15 ng/mL) survived, whereas 29% of the patients with low Hsp 72 serum levels died from their traumatic injuries (p = 0.01). The overall mortality was 21%, occurring within 5 to 7 days. Patients who died were older (mean age, 54 +/- 15 years) than those who survived (mean age, 36 +/- 15 years) (p < 0.0.05). The cause of death was attributable to head injury in 79%, although the severity of head injury (Abbreviated Injury Scale score) was not statistically different between survivors with high serum values of Hsp 72 and patients who died. There was no correlation between the initial serum Hsp 72 values and the severity of organ dysfunction or clinical indicators of the inflammatory response. Hsp 72 can be detected in the serum of severely traumatized patients within 30 minutes after injury. Elevated initial serum levels of Hsp 72 (serum levels > 15 ng/mL) are associated with survival after severe trauma, but are not related to the incidence or severity of the postinjury inflammatory response or organ dysfunction.