Pretreatment with IFN-gamma decreases infectious complications after partial hepatectomy in the rat

Pneumonia as a long-term consequence of chronic psychological stress in BALB/c mice

Recently, we have shown that female BALB/c mice are highly sensitive to chronic psychological stress. They develop systemic neuroendocrine disturbances, a hypermetabolic syndrome, behavioral alterations and severe immunosuppression with a reduced antibacterial response during experimental infection. Here, we show that chronically stressed mice spontaneously suffered from increased bacterial load in the liver and lung that sustained for up to 10 days after the termination of stress exposure. Immediately after the last chronic stress cycle, splenocytes had a reduced ability to produce IFNgamma after ex vivo stimulation with LPS while showing enhanced inducibility of IL-10. When healthy animals were treated with anti-IFNgamma antiserum the antibacterial response against the small numbers of endogenous bacteria that physiologically penetrate the intestinal barrier was reduced causing increased bacterial burden in the liver. Thus, a deficient antibacterial response to translocated commensals in chronically stressed animals can contribute to long-lasting pneumonia.

[Significance of liver trauma for the incidence of sepsis, multiple organ failure and lethality of severely injured patients. An organ-specific evaluation of 24,771 patients from the trauma register of the DGU]

BACKGROUND

The prognosis of multiple injured patients is mainly limited by initial severe hemorrhage causing hemorrhagic shock, subsequent sepsis and multiple organ failure (MOF). Although mechanisms of altered microcirculation, cytokine release etc. have been intensively investigated, little is known about the relevance of severe liver trauma as an independent predictive outcome factor in these patients. This study aimed to clarify the impact of severe liver trauma in one of the largest trauma databases.

PATIENTS AND METHODS

The study was based on data from the German trauma register within the German Society for Trauma Surgery (DGU) and 24,711 patients from 113 hospitals were collected for retrospective analysis between 1993 and 2005. Patients with an injury severity score (ISS) >16, no isolated head injury and primary admission to a trauma center were included. Data were allocated according to the injury pattern into I liver group (severe damage of the liver, AIS>3 and AIS abdomen <3), II Abdomen group (severe abdominal trauma AIS>3, AIS liver <3) and III Control group (liver and/or abdominal trauma AIS<3, other trauma AIS>3).

RESULTS

Out of 24,771 multiple injured patients from 113 trauma centers, 321 individuals were identified which matched the criteria of the liver group. Another 574 patients were allocated to the abdomen group while the majority of patients formed the trauma group (9574). Severe injury of the liver is associated with excessive demands for volume resuscitation and induces a significantly increased risk for sepsis and MOF compared to both other groups (sepsis 19.9% vs 11%; MOF 32.7% vs 16.6%). Furthermore, deleterious outcome is more frequent associated with patients with severe liver trauma (lethality 34.9%) compared to severe abdominal trauma (12%) and the control group (19.5%).

CONCLUSIONS

Severe liver trauma is an independent predictor for severe hemorrhage with a substantial increased risk of sepsis, MOF and trauma-related death. While conservative treatment of patients with severe liver trauma but no hemorrhage is effective, patients with hemodynamic instability seem to form a subgroup where contemporary treatment modalities are not yet sufficient.

The effect of mesenteric lymphadenectomy and Kupffer cell depletion on bacterial translocation

BACKGROUND

Infectious complications are associated with high morbidity in patients with short bowel syndrome and after small bowel transplantation. Bacterial translocation from the intestine is probably an essential factor in the genesis of these infections. In a model for bacterial translocation in the rat we examined the consequence of mesenteric lymphadenectomy and the depletion of Kupffer cells.

MATERIALS AND METHODS

The effect of mesenteric lymphadenectomy was studied in two different models; in rats where a Thiry-Vella loop had been created from small bowel and in rats that had received a syngeneic small bowel transplant. To study the role of the Kupffer cells, rats with Thiry-Vella loops were treated intravenously with the Kupffer cell inhibitor gadolinium chloride. All animals were sacrificed on Day 3 postoperatively and the bacterial translocation to the mesenteric lymph nodes, liver, spleen, lung, and blood was evaluated.

RESULTS

Removal of the mesenteric lymph nodes did not result in any increased bacterial translocation in animals with a Thiry-Vella loop. However, the inactivation of Kupffer cells with gadolinium chloride produced a more severe translocation to the liver, spleen, and lungs. After small bowel transplantation the bacterial translocation to the spleen was increased in animals without mesenteric lymph nodes.

CONCLUSIONS

In the model of bacterial translocation from a defunctionalized loop of small bowel the inhibition of Kupffer cells will promote the systemic spread of the translocating bacteria. This indicates an important protective function of the Kupffer cells against translocating microbes.