Treatment Of Gram-negative Septic Shock Research Articles

Reconstituted High-Density Lipoprotein Reduces LPS-Stimulated TNFα

Reconstituted high-density lipoprotein (rHDL), an artificial lipoprotein consisting of apolipoprotein A-I and phosphatidylcholine (1:150, molar ratios) dose-dependently reduces lipopolysaccharide (LPS)-induced tumor necrosis factor-α (TNF) production in in vitro, ex-vivo, and in-vivo model systems. In an in-vitro whole blood assay, rHDL (1 mg/ml) added concomitantly with LPS increased cellular resistence to LPS stimulation ∼1000-fold. Even with extremely high levels of LPS (10 μg/ml), rHDL, ⩾0.5 mg/ml caused >50% decrease in TNF production. Preincubation of rHDL with LPS was not required for activity. rHDL (⩾1 mg/ml) reduced TNF production by 50% even when added to cultures 2 hr after their stimulation with LPS (10 μg/ml). In an ex-vivo study, rabbits were infused with rHDL at doses of 25, 50, and 75 mg/kg. Blood was drawn and stimulated with LPS ex vivo and bioactive TNF was assessed using the L929 cytotoxicity assay. Fifteen minutes after rHDL infusion, there was a significant difference in ex-vivo-induced TNF activity between groups (750 ± 160, 170 ± 40, 80 ± 30, 60 ± 30 pg TNF/ml, for the control, 25, 50, and 75 mg/kg rHDL dose groups, respectively; P < 0.0001). The duration of ex-vivo TNF inhibition was dependent on the dose of rHDL. Even at 2 hr, rHDL showed a pronounced TNF inhibition (control: 950 ± 120 pg TNF/ml; 75 mg/kg: 140 ± 60 pg TNF/ml). Further studies showed that a prophylactic infusion of rHDL diminished LPS-induced TNF production in a rabbit endotoxemia model. Anesthetized rabbits were infused with saline or rHDL (25 or 50 mg/kg) 15 min prior to the infusion of LPS (5 μg/kg/hr for 2 hr). One hour after the beginning of LPS infusion, TNF was significantly decreased in the treatment groups (7.54 ± 1.89, 2.22 ± 1.17, 2.23 ± 0.72 ng TNF/ml for control, 25, and 50 mg/kg, respectively; P = 0.02). rHDL not only delayed TNF production, but caused a reduction in peak TNF levels (20.4 ng versus 6.7 and 4.4 ng TNF/ml in the saline recipients or 25 and 50 mg/kg groups, respectively, P = 0.058). Hypotension was also reduced. In aggregate, these data confirm rHDL ability to block LPS, modulating TNF release and the physiological sequelae associated with LPS shock. If the physiological benefit of rHDL is confirmed in clinical trials, rDHL may represent a new approach to the prohylaxis and treatment of gram-negative septic shock.

Protective Effects Of A Recombinant Amino-Terminal Fragment Of Human Bactericidal/Permeability-Increasing Protein In An Animal Model Of Gram-Negative Sepsis

Bactericidal/permeability-increasing protein (BPI) has bactericidal properties and also binds lipopolysaccharide (LPS). The ability of a recombinant amino-terminal fragment of BPI to protect mice from death after challenge with a number of different strains of Escherichia coli was tested. BPI prevented death in animals challenged with the J5 rough strain but not with smooth strains O111:B4 and O7K1. Protection was associated with a reduction in serum LPS and tumor necrosis factor-alpha levels but not with reduction in blood bacterial counts. BPI was effective at protecting against death in mice injected with purified O111:B4 LPS. Lack of protection after injection with live O111:B4 and O7K1 may be due to production by these models of approximately 1000-fold higher blood bacterial count compared with J5. Thus, BPI is a promising therapy in the treatment of gram-negative septic shock, although the range of organisms against which it is effective remains to be determined.

Treatment of Gram-Negative Septic Shock With an Immunoglobulin Preparation

Treatment of Gram-Negative Septic Shock With an Immunoglobulin Preparation

Treatment of Gram-negative septic shock with an immunoglobulin preparation

To evaluate the effectiveness of a polyclonal immunoglobulin (Ig) preparation containing IgG, IgM, and IgA as an adjunctive therapy for septic shock. Prospective, randomized clinical trial. A clinical immunology ward at the center for internal medicine in a university hospital. Fifty-five patients with septic shock were randomly allocated to two groups according to criteria of septic shock. One group of patients (n = 27) received a commercially available immunoglobulin preparation (containing high titers of antibodies specific for determinants to bacterial endotoxin) during the first 3 days after inclusion in the study. The other randomized group (n = 28) did not receive any immunoglobulin preparation. During the period of less than or equal to 6 wks after the beginning of clinically apparent septic shock, death related to the septic process occurred in one (4%) of 27 patients who received immunoglobulin. By comparison, nine (32%) of 28 control group patients died during this period (p less than .01). Within the first 48 hrs after onset of the clinically apparent septic process, significantly increased activity of circulating endotoxin and simultaneously decreased specific IgG serum titers to lipid A were detected in the group of nonsurvivors. Administration of a polyclonal immunoglobulin preparation in the early phase of septic shock was associated with significantly improved survival.