rwj-67657 and Endotoxemia

Despite extensive knowledge about the mechanisms behind sepsis, this syndrome still caries a large morbidity and mortality rate. Dysregulated immune and coagulation systems are held responsible. However, additional pathophysiological mechanisms such as uncontrolled apoptosis induced by death receptor ligands might well play a role. P38 mitogen-activated protein (MAP) kinase inhibitors are considered as potential drugs in inflammatory diseases. Therefore, the effect of endotoxin administration on the response of soluble(s) tumor necrosis factor-related apoptosis-inducing ligand (sTRAIL), a death receptor ligand, and the role of p38 MAP kinase inhibition was studied in 21 human volunteers. The volunteers received 30 min before the endotoxin infusion a single oral dose of placebo or the selective p38 MAP kinase inhibitor drug, RWJ-67657. Plasma sTRAIL increased 10-fold to 6564 +/- 511 pg/mL after 2.5 h. This increase was blocked completely by the highest dose of RW-J6765. This is the first report showing that endotoxin increases sTRAIL where the p38 MAP kinase signaling pathway is involved.

Topics: Adult; Apoptosis; Apoptosis Regulatory Proteins; Endotoxemia; Endotoxins; Humans; Imidazoles; Ligands; Male; MAP Kinase Signaling System; Membrane Glycoproteins; p38 Mitogen-Activated Protein Kinases; Pyridines; Signal Transduction; Time Factors; TNF-Related Apoptosis-Inducing Ligand; Tumor Necrosis Factor-alpha

Sepsis resulting in multiorgan failure and death is still a major problem in intensive care medicine, despite extensive attempts to interfere in the supposed underlying mechanism of a deranged immune system. This is not only due to the persistent lacunae in knowledge about the immune system in sepsis but also due to the lack of sufficient instruments for intervention. Inhibitors of the p38 mitogen-activated protein kinase (p38MAPK) have been used to study the signalling pathway of the immune response. In vitro and animal studies have demonstrated that blocking p38MAPK could mitigate the pro-inflammatory response and improve survival after endotoxaemia. Using an endotoxaemia model in healthy human volunteers we evaluated the attenuation of clinical and cytokine response to endotoxin after inhibition of p38MAPK by an oral dose of RWJ-67657, a pyrindinyl imidazole. We measured the clinical parameters temperature, blood pressure and heart rate. The proinflammatory cytokines tumour necrosis factor-alpha, interleukin-6 and interleukin-8 were measured by ELISA at various points during a 24-h period. Drug toxicity was evaluated by routine clinical and laboratory examinations. After a single dose dose of RWJ-67657 the temperature and blood pressure response remained at the basal level. The inhibition of TNF-alpha, IL-6 and IL-8 response was a dose dependent. With the maximum dosage, reduction in peak serum levels of the proinflammatory cytokines was greater than 90%. There was no drug-related toxicity.. We conclude that inhibition of p38MAPK by RWJ-67657 might be a tool to intervene in the deranged immune response in sepsis and other inflammatory diseases.

Topics: Adult; Cytokines; Dose-Response Relationship, Drug; Endotoxemia; Endotoxins; Enzyme Inhibitors; Fever; Humans; Hypotension; Imidazoles; Interleukin-6; Interleukin-8; Male; MAP Kinase Signaling System; Mitogen-Activated Protein Kinases; p38 Mitogen-Activated Protein Kinases; Pyridines; Tumor Necrosis Factor-alpha

In the present study, we investigated the effect of RWJ-67657, a p38 MAP kinase inhibitor, upon in vivo LPS-induced monocyte cytokine production and upon monocyte LPS-hyporesponsiveness. Thirty minutes before a single injection of LPS (4 ng/kg BW), healthy male volunteers received a single oral dose of RWJ-67657 at increasing dosages (0-1400 mg). Blood samples (pre-medication, 3, 6 and 24 h after LPS) were immediately incubated with LPS (reflecting LPS-hyporesponsiveness) or without LPS (reflecting in vivo monocyte stimulation) for 4 h at 37 degrees C. Following red blood cells lysis and white blood cell permeabilization, cells were labelled with alpha-CD14-FITC and alpha-IL-1beta, alpha-IL-12 or alpha-TNFalpha (PE-labelled), fixed, and analysed using flow cytometry. In vivo LPS injection resulted in an increased percentage of circulating monocytes producing IL-1beta, TNFalpha and IL-12 only at 3 h after the LPS injection. This was dose-dependently inhibited by RWJ-67657 treatment. LPS-hyporesponsiveness to in vitro LPS treatment was most prominent at 3 and 6 h after the in vivo LPS injection; compared with pre-medication monocytes, at these intervals a reduced percentage of monocytes produced IL-1beta, TNFalpha or IL-12 after the in vitro LPS stimulus. At t = 6 h, this LPS-hyporesponsiveness could dose-dependently be inhibited by RWJ-67657 treatment of the volunteers. We therefore conclude that p38 MAP kinase inhibition with RWJ-67657 inhibited monocyte production of cytokines following in vivo LPS injection. Treatment with RWJ-67657 also reversed the LPS-hyporesponsiveness. Whether this result can be extended to the clinical situation remains to be elucidated. Patients with sepsis or an otherwise high risk for multi-organ failure are potential study groups.

Topics: Endotoxemia; Enzyme Inhibitors; Gene Expression Regulation; Humans; Imidazoles; Interleukin-1; Interleukin-12; Lipopolysaccharides; Male; Mitogen-Activated Protein Kinases; Monocytes; p38 Mitogen-Activated Protein Kinases; Pyridines; Shock, Septic; Tumor Necrosis Factor-alpha

Topics: Endotoxemia; Enzyme Inhibitors; Humans; Imidazoles; Mitogen-Activated Protein Kinases; Neutrophils; p38 Mitogen-Activated Protein Kinases; Pyridines; Research; Sepsis