Plasma Of Septic Patients Research Articles

Exosomes derived from plasma of septic patients induce myocardial dysfunction

Exosomes derived from plasma of septic patients induce myocardial dysfunction

P22phox-containing microparticles from plasma of septic patients are related to reactive oxygen species production and apoptosis of vascular cells in culture

Reactive oxygen species (ROS) are related to vascular dysfunction in several pathologies and may be related to the pathophysiology of sepsis and multiple organ dysfunction. To investigate their role and sources we evaluated the effects of plasma of septic patients (SPP) on reactive ROS production and apoptosis of rabbit endothelial (REC) and aortic smooth muscle (RASM) cells in culture through NAD(P)H (0.3 mM)-driven lucigenin (5 μM) luminescence and annexin V assay respectively. SPP alone showed intrinsic luminescence when compared to plasma from healthy controls (HCP) (51.4 ± 9.5 cpm/min/mg protein vs 7.0 ± 1.2, n = 5, P < 0.05). After incubation with REC and RASM cells SPP induced a two-fold increase in ROS production (n = 5, P < 0.05) when compared to incubation with HCP. This enhancement of ROS production by REC and RASM cells were paralleled by increase in apoptosis rates induced by SPP. The fraction responsible for ROS production and apoptosis induction was determined through filtration and ultracentrifugation to be over 50 kD and to contain microparticles (MP), similar to those from activated platelets. MP showed similar luminescence (60.6 ± 4.4 vs 32.9 ± 3.1, n = 11), blocked by DPI (60%), a flavoenzyme inhibitor, and by SOD (80%). Addition of MP from SPP to REC and RASM also induced increased luminescence when compared to the effect of MP from HCP; These signals were also inhibitable by SOD and DPI. Incubation of REC and RASM with MP from SPP doubled apoptosis rates when compared to incubation with MP from HCP. Apoptosis was also inhibited by addition of SOD or DPI. After lipid extraction, western-blot analysis of the MP was positive for the p22phox and gp91 subunits of the NAD(P)H oxidase. Thus, SPP has intrinsic and enhances REC and RASM ROS production, due to NAD(P)H oxidase activity. It causes apoptosis of REC and RASM, also inhibited by SOD and DPI. These effects may be attributable to MP containing the p22phox and gp91 subunits of NAD(P)H oxidase. ROS derived from microparticles may represent a new signaling pathway involved in the pathophysiology of severe sepsis.

Apoptosis of vascular cells in culture and reactive oxygen species generation following exposure to plasma of septic patients

The inflammatory response that occurs in sepsis has been related to the presence of cytokines, and also other soluble factors such as fas and fas-l, which can induce apoptotic cell death of endothelial cells. Also, it can result in endothelial dysfunction, with microvascular thrombosis and activation of the coagulation cascade. These events involve the transduction of extracellular stimuli by reactive oxygen species (ROS; O2•-, H2O2) that result in activation of intracellular signaling pathways like MAPKinases. We sought to evaluate the effect of soluble factors present in plasma of septic patients in rabbit endothelial (REC) and vascular smooth muscle cells (RASM) in culture, by assaying for apoptosis with a TUNEL detection method. Also, we assessed NAD(P)H oxidase production of ROS in these plasma samples and in REC and RASM homogenates after incubation with plasma, as assessed with the lucigenin 5 μM chemiluminescence technique. Septic plasma showed ROS generation when incubated with NADPH but not with NADH (51.44 ± 21.18 and 8.90 ± 4.04 versus 7.77 ± 2.60 and 1.8 ± 0.99 cpm × 103/mg/min, NADPH and NADH versus controls, respectively; n = 5-3). When incubated with homogenates of REC or RASM in the presence of both NADH or NADPH, septic plasma caused a 2- to 3-fold increase in ROS generation versus healthy control plasma (n = 5-3). Thus, septic plasma lead to apoptosis of REC and RASM, abrogated by a SOD mimic and NAD(P)H oxidase inhibitor DPI. Intrinsic NADPH oxidase ROS production was detected in the septic plasma. It also enhanced the NAD(P)H oxidase ROS production in REC and RASM homogenates. These data suggest that in sepsis there is a possible link between ROS production and vascular cell apoptosis. Table

Detection of DNA in the plasma of septic patients.

Small amounts of plasma-free DNA have been observed both in healthy individuals and in patients with various diseases such as systemic lupus erythematosus, rheumatoid arthritis, viral hepatitis, and cancer. This communication demonstrates that septic patients also release DNA in plasma. After DNA extraction from plasma, exon 1 of the K-ras gene was amplified by PCR and products were analyzed by dot-blot hybridization. Plasmas from polytraumatic patients and control healthy individuals were used for comparisons with septic patients. Our results show that septic patients present DNA in their plasma. As far as we know, this is the first evidence of circulating DNA in septic patients.

Endotoxin concentration by Limulus assay correlates with biological activity in mice and human peripheral blood mononuclear cells

Endotoxin is thought to play a major role in septic shock and multiple systemic organ failure (MOF). However, endotoxin is not always detected in the plasma during Gram-negative sepsis by current Limulus lysate assays. Additionally, it is unknown to what extent the biological activity of endotoxin is truly reflected in endotoxemia. This paper assesses quantitatively a comparison of three types of Limulus assays for the detection of the biological activity of endotoxin in plasma. Mouse lethal activity and TNF production were used for assessment of the biological activity of endotoxin both before and after potential modification of LPS activity by plasma constituents. We have concluded that the dilution and heating method coupled with a toxinometer provides the most accurate correlation with other biological activities of endotoxin in plasma. The fact that the biological activity of endotoxin decreased to 17% of initial dose after incubation at 37ºC for 90 min in normal plasma suggests further a temporal dependence of time in plasma upon the manifestation of biological activities normally attributable to this biologically active microbial constituent found in the plasma of septic patients.

PLASMA LEVELS OF PEPTIDOGLYCAN DETECTED WITH SILKWORM LARVAE PLASMA IN SEPTIC PATIENTS

PLASMA LEVELS OF PEPTIDOGLYCAN DETECTED WITH SILKWORM LARVAE PLASMA IN SEPTIC PATIENTS

Plasminogen: An Important Hemostatic Parameter in Septic Patients

Previously we observed in some but not all septic patients a low plasma concentration of plasminogen. To investigate prospectively whether plasma levels of plasminogen or the ratio of plasminogen to alpha-2-antiplasmin have a prognostic value for survival from sepsis and to study the variation of other hemostatic parameters during septicemia. The study population consisted of 45 consecutive patients with septicemia, 15 non-septic patients from the same intensive care unit and 30 healthy volunteers. Plasminogen concentrations were significantly lower (p < 0.001) in plasma of septic patients (median 0,62 IU/ml range: 0.15-1,06) than in plasma of healthy controls (median 1.00 IU/ml, range: 0.75-1.10) or of non-septic intensive care patients (median 1.00 IU/ml, range: 0.82-1.08). Among the other parameters tested, plasminogen activator inhibitor (PAI-1) antigen concentration and PAI activity were similar in septic and non-septic intensive care patients, but higher than in healthy controls. Concentrations of elastase-alpha-1-protease inhibitor or of thrombin-antithrombin complexes were higher in septic patients than in non-septic intensive care patients or healthy controls. A degraded form of plasminogen of 38 kDa was detected by Western blot analysis in the plasma of septic patients, but not in plasma of non-septic intensive care patients or controls. Plasminogen alone or the ratio of plasminogen to antiplasmin were good markers for survival from septicemia. E.g. for plasminogen at a cut off of 0.65 IU/ml, sensitivity was 90.5% and specificity 66.7%, whereas for the ratio of plasminogen over antiplasmin at a cut off ratio of 0,65 IU/ml, sensitivity was 95.2% and specificity 70.8%. Plasminogen or the ratio of plasminogen to antiplasmin are sensitive markers for survival in patients with septicemia.

Amino acid kinetics in plasma of septic patients : G.Kleinberger, W.Druml, A.Laggner, K.Lenz, B.Schneeweiß (1st Dept. of Internal Medicine, University of Vienna, Austria)

Amino acid kinetics in plasma of septic patients : G.Kleinberger, W.Druml, A.Laggner, K.Lenz, B.Schneeweiß (1st Dept. of Internal Medicine, University of Vienna, Austria)

Clinical and experimental observations on the significance of endotoxemia.

Endotoxin-like materials, when sought in the plasma of septic patients, are found principally in association with infections due to gram-negative organisms, although positive tests are occasionally encountered under other circumstances. Many patients with infections due to gram-negative rods do not yield positive reactions, and positive reactions are not strong indicators of bacteremia or fatal outcome. Experiments in which hemorrhagic hypotension was induced in rabbits indicate that endotoxin-like materials are probably released from gram-negative gut flora but do not increase or decrease the rate of lethal outcome of controlled hemor-