A promising approach in sepsis therapy is the use of peptides truncated from serum- and membrane-proteins with binding domains for LPS: antimicrobial peptides (AMPs). AMPs can be useful in combination with conventional antibiotics to increase killing and neutralize LPS. Although many AMPs show a high specifi city towards bacterial membranes, they can also exhibit toxicity, i.e. non-specifi c membrane lysis, of mammalian cells such as erythrocytes and therefore, unsuitable as systemic drugs. A way to overcome this problem may be an extracorporeal therapy with immobilized peptides. This study will compare neutralization of LPS using different AMPs in solution and when immobilized on to solid phases. The peptides ability to neutralize LPS-induced cytokine release in whole blood will also be tested. The peptides are truncated derivates from the known AMPs LL-37, SC4, BPI, S3Δ and CEME. Two different methods were used to immobilize peptides, biomolecular interaction analysis, and Pierce SulfoLink Coupling Gel. To investigate LPS binding in solution the LAL test was used. After whole blood incubation with LPS and AMPs ELISA was used to measure TNF α , IL-1 β and IL-6 production. The results suggest that immobilization of antimicrobial peptides does not inhibit their capacity to neutralize LPS, although there are differences between the peptides tested. Thus, peptides derived from LL-37 and CEME were more effi cient both in LPS binding and neutralizing LPS-induced cytokine production

Interactions of bacterial and host products in activating the innate immune system is an important area to address. The role of lipoteichoic acid (LTA) in these interactions is particularly important because it is understudied in comparison to other factors. This study evaluated the effect of cationic peptides (CPs) on LTA-induced proinflammatory cytokine production in human whole blood and on purified leukocytes. Four different CPs of truncated derivatives from the known peptides LL37, BPI, and CP207 were used. Two of the CPs (IG33 and LL33), derivatives from LL37, potentiated S. aureus LTA induced TNFα, IL-6 and IL-1β production in whole blood. The release of TNFα was increased 30-fold after 16 hours incubation. Intact LL37 also increased LTA-induced TNFα and IL-1β in a time dependent manner. LTA in combination with either LL33 or IG23 demonstrated a synergistic enhanced TNFα and IL-1β secretion on isolated leukocytes but not on purified monocytes. When complexed with IG23 and LL33, the electrophoretic mobility of LTA was altered in a non-denaturating gel electrophoresis. LTA was disaggregated and migrated more rapidly, suggesting an amphiphilic effect of CPs on LTA. In conclusion, LTA synergizes with LL37 and its truncated derivatives and this may lead to proinflammatory cytokine production and cause problems in sepsis therapy.

Abstract: It has been suggested that soluble urokinase plasminogen activator (suPAR) can be used as a marker of disease severity and risk of mortality in sepsis. The aim with the present study was to compare plasma levels of suPAR in patients with severe sepsis to control subjects and correlate it with the level of inflammatory activation, severity and mortality. Samples were collected from 27 sepsis patients at the intensive care unit (ICU), Lund, Sweden; 90-day mortalities were registered. The suPAR level was significantly elevated in sepsis patients compared to controls, but not significantly higher in nonsurvivors than survivors. Plasma levels of suPAR did correlate weakly with the SOFA score and myeloperoxidase (MPO) but not with CRP, PCT, IL-6 or IL-10 in patients with severe sepsis. The weak correlation between suPAR and other inflammatory markers might suggest that suPAR reflects general activation of the immune system rather than exerting inflammatory actions.

The soluble urokinase plasminogen activator receptor (suPAR) has been detected in blood, plasma, serum, urine, ovarian cystic fluid, and cerebrospinal fluid. Elevated suPAR levels in plasma have been associated with negative outcomes in various diseases, such as bacteremia, sepsis, SIRS, cardiovascular disease, cancer, and tuberculosis. The primary aim of this study was to investigate whether suPAR can be detected in saliva from healthy individuals and thus, if saliva suPAR can be related to plasma suPAR, CRP, BMI, or gender. Blood and unstimulated whole saliva was collected from 20 healthy individuals (10 female and 10 male, median age of 28 years; range 21–41). CRP and suPAR were measured with ELISA in saliva and serum/plasma. suPAR was detected in all saliva samples in the 5.2–28.1 ng/mL range, with a median value of 17.1 ng/mL. Saliva suPAR was significantly higher (P , 0.001) but not correlated to plasma suPAR in healthy young adults with normal plasma suPAR levels. suPAR and CRP levels were correlated in blood but not in saliva. No correlation was found between BMI, age, or gender and suPAR in saliva.