Endogenous protein C has a protective role during Gram-negative pneumosepsis (melioidosis).

BACKGROUND: Activated protein C (APC) exerts anticoagulant effects via inactivation of factors Va and VIIIa and cytoprotective effects via protease activated receptor (PAR)1. Inhibition of endogenous APC in endotoxemia and sepsis results in exacerbation of coagulation and inflammation, with consequent enhanced lethality. OBJECTIVES: We here sought to dissect the distinct roles of the anticoagulant and cytoprotective functions of endogenous APC in severe Gram-negative pneumonia-derived sepsis (melioidosis). METHODS: We infected wild-type (WT) mice with Burkholderia pseudomallei, a common sepsis pathogen in southeast Asia, and treated them with antibodies inhibiting both the anticoagulant and cytoprotective functions of APC (MPC1609) or the anticoagulant functions of APC (MAPC1591) only. Additionally, we administered SEW2871 (stimulating the S1P1-pathway downstream from PAR1) to control and MPC1609-treated mice. RESULTS: MPC1609, but not MAPC1591, significantly worsened survival, increased coagulation activation, facilitated bacterial growth and dissemination and enhanced the inflammatory response. The effects of MPC1609 could not be reversed by SEW2871, suggesting that S1P1 does not play a major role in this model. CONCLUSIONS: These results suggest that the mere inhibition of the anticoagulant function of APC does not interfere with its protective role during Gram-negative pneumosepsis, suggesting a more prominent role for cytoprotective effects of APC .

Plasminogen activator inhibitor type I contributes to protective immunity during experimental Gram-negative sepsis (melioidosis).

BACKGROUND: Melioidosis is a frequent cause of sepsis in Southeast Asia caused by the Gram-negative bacterium Burkholderia pseudomallei. Patients with melioidosis have elevated circulating levels of plasminogen activator inhibitor type 1 (PAI-1), an important regulator of inflammation and fibrinolysis. OBJECTIVES: In this study, we aimed to investigate the role of PAI-1 during melioidosis. METHODS: Wild-type (WT) and PAI-1-deficient (PAI-1-/1(-/-) ) mice were intranasally infected with B. pseudomallei. Mice were killed after 24, 48 or 72 h. Lungs, liver and blood were harvested for measurement of bacterial loads, cytokines, clinical chemistry, histopathology, and coagulation parameters. Additionally, survival studies were performed. RESULTS: PAI-1(-/-) mice demonstrated enhanced susceptibility to B. pseudomallei infection, as shown by a strongly increased mortality rate (100% vs. 58% among WT mice, P < 0.001), associated with enhanced bacterial loads in lungs, liver, and blood. Additionally, PAI-1(-/-) mice showed elevated levels of proinflammatory cytokines in lungs and plasma, accompanied by enhanced local and systemic coagulation activation (thrombin-antithrombin complexes and D-dimer), increased hepatocellular injury (plasma aspartate aminotransferase and alanine aminotransferase), and renal failure (plasma creatinine and urea). CONCLUSIONS: PAI-1 has a protective role during severe Gram-negative sepsis caused by B. pseudomallei by limiting bacterial growth, inflammation, and coagulation, and probably, as a consequence thereof, distant organ injury.

[Diagnostic image (316). A woman who died despite resuscitation. Pulmonary bone marrow embolism secondary to a sternum fracture]. / Diagnose in beeld (316). Een vrouw overleden ondanks reanimatie.

A 75-year-old woman was unsuccessfully resuscitated. Post-mortem investigation showed pulmonary bone marrow embolism secondary to a sternum fracture probably caused by the external cardiac massage.