Characteristics of AE associated with Heparin & Dialysis 2000–2010.

<p>Characteristics of AE associated with Heparin & Dialysis 2000–2010.</p

OSCS-induced kallikrein activation in patient plasma samples.

<p>(A) OSCS-induced kallikrein activation and (B) functional C1inh levels in plasma samples from normal individuals (n = 40) and from patients with septic shock (n = 32). (C) The relationship of OSCS-induced kallikrein activity and functional C1inh levels using the same samples. The error bars correspond to mean ± SD for each patient group. The correlation coefficient r = −0.413 indicates a negative association between functional C1inh levels and OSCS-induced kallikrein activation. Data shown here were representative of three independent experiments.</p

Complement components C1r and C1s compete with FXIIa for C1inh.

<p>Kallikrein activity of (A) different doses of prekallikrein incubated with a fixed dose (1 ng) of FXIIa; (B) a fixed dose (0.5 µg) of prekallikrein incubated with different doses of FXIIa; (C) different doses of C1inh premixed with a fixed dose (1 ng) of FXIIa before combining with prekallikrein (1 µg). (D) Kallikrein activity of 0.5 µg of prekallikrein incubated with different combinations of FXIIa, C1inh and C1r/C1s. Experiments were repeated independently at least three times. Duplicate samples were used in panels C and D.</p

Factors that can influence bradykinin levels.

<p>The level of bradykinin (BK) is determined by the levels of kallikrein (KAL), high molecular weight kininogen (HMWK) and enzymes that degrade BK, such a angiotensin converting enzyme (ACE), aminopeptidase P (APP) and neutral carboxypeptidase (CPN). Activated factor XII (FXIIa) generates KAL from prekallikrein (PK). C1 inhibitor (C1inh) can inhibit both FXIIa and KAL. OSCS can facilitate FXIIa activity through enhancing its generation from FXII and/or stabilizing a complex of FXIIa, PK and HMWK. OSCS may also have a direct effect on C1inh. Other factors in the complement pathway and coagulation cascade can interact with C1inh and thus decrease C1inh availability for limiting BK production.</p

OSCS kallikrein activation kinetics and dose response.

<p>(A) Kinetics of kallikrein activation in normal plasma and C1inh-depleted plasma with the addition of 25 µg/ml of OSCS. Kallikrein activity was also determined in (B) normal human plasma and (C) C1inh-depleted plasma with different doses of OSCS. The OSCS dose response was also evaluated with plasma samples treated with antibody-coated bacteria. Experiments were repeated independently twice. Duplicate samples were used in panel A.</p

Bacteria incubation consumes C1 inhibitor and increases OSCS-induced kallikrein activity.

<p>(A) Natural antibody-coated <i>E. coli</i> BL21 bacteria were incubated with human plasma at 37°C, washed by PBS, and the level of C1 inhibitor deposited on the bacteria was determined by addition of horseradish peroxidase-conjugated anti-C1 inhibitor antibody and then developement with ABTS substrate as described in the Materials and <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0034978#s2" target="_blank">Methods</a>. (B) An ELISA assay showed decreased C1 inhibitor levels in plasma treated with antibody-coated <i>E. coli</i> BL21 bacteria. (C) OSCS and OSCS-contaminated heparin induced kallikrein activity were increased in plasma treated with antibody-coated bacteria as compared to untreated plasma. PBS, CSA or uncontaminated heparin did not induce kallikrein activity in either plasma. (D) Kallikrein activity in plasma treated with or without antibody-coated <i>E. coli</i> BL21 bacteria, C1 inhibitor (200 µg/ml), or OSCS (25 µg/ml) was measured. Data shown were representative of three independent experiments.</p