Early time course of altered leukocyte response to lipopolysaccharide and peptidoglycan in porcine gunshot injury.

BACKGROUND: Penetrating injuries are frequently combined with polybacterial soiling. Clearance of the microorganisms depends on the ability to activate immune responses, but post-traumatic hyporeactivity of immune cells is almost universal. The aim of this study was to map the early time course of this altered leukocyte reactivity, and to compare the reactions to subsequent Gram-positive or Gram-negative challenges. METHODS: Twelve juvenile pigs sustained two standardized rounds, one through the right femur and one through the left upper abdomen. First aid treatment and acute surgery were started immediately. Blood samples were drawn before trauma and after 10, 30, 60, and 90 min, and thereafter stimulated in ex vivo whole blood for 3 h with lipopolysaccharide (LPS, 10 ng/ml), peptidoglycan (PepG, 1 microg/ml), or an equivalent amount of normal saline. The leukocyte response was evaluated by measurement of tumor necrosis factor (TNF)-alpha, interleukin (IL)-1 beta, IL-6, IL-8, and IL-10 in the supernatant. RESULTS: In the post-traumatic in vivo serum, the concentration of TNF-alpha increased steadily (significant after 60 min). A reduced ex vivo reaction to LPS was evident after 10 min, and was statistically significant after 30 min. The lowest levels were reached after 90 min. The ex vivo synthesis of TNF-alpha after stimulation with PepG remained unaltered. A similar development was seen for IL-6. IL-1 beta levels did not change, while IL-8 increased significantly only after 60 and 90 min. CONCLUSIONS: Trauma almost instantaneously reprogrammed circulating leukocytes. As measured with TNF-alpha, a profound hyporeactivity to LPS, but not to PepG, was induced. In addition, no global down-regulation of leukocyte function was found after stimulation with LPS.

Capacity of glycine to modulate early inflammatory disturbances after serious gunshot injuries in the pig.

OBJECTIVE: Perturbation of immune homeostasis is an important determinant for organ dysfunction following multiple injuries. The aim of this study was to investigate the ability of glycine to influence the immediate post-traumatic inflammatory environment and altered reactivity of circulating leucocytes. MATERIAL AND METHODS: Twenty pigs were subjected to two standardized gunshots to the abdomen and thigh. Treatment was started immediately. The animals were randomized to receive either glycine 180 mg/kg i.v. over 30 min (n=10) or normal saline (n=10). Blood samples were drawn at baseline and 75 min after injury. In a follow-up study 12 pigs were exposed to an identical trauma. Blood was drawn at the same time-points and stimulated with lipopolysaccharide (LPS) or LPS plus glycine for 2 h in an ex vivo whole blood model. RESULTS: Selected physiologic variables and organ injury did not differ between groups 75 min after trauma. Reactive oxygen species decreased to 82.7+/-5.5 % of baseline (p<0.05) in the glycine group (unaltered in the controls). Liver glutathione concentrations decreased in parallel in both groups. In vivo production of TNF-alpha and IL-1-beta increased to the same extent regardless of treatment. Trauma induced a strong LPS tolerance. In whole blood challenged with LPS, glycine inhibited cytokine synthesis, but only in samples drawn at baseline. CONCLUSIONS: Post-traumatic infusion of glycine only modestly influenced the early post-traumatic inflammatory environment. Our ex vivo results confirm previous reports on the anti-inflammatory potential of glycine, but restricted to pre-trauma conditions.