Caspase-3 Activation, Bcl-2 Contents, and Soluble FAS-Ligand Are Not Related to the Inflammatory Marker Profile in Patients with Sepsis and Septic Shock

Organ-specific effects on inflammation and apoptosis of recombinant human activated protein C in a murine model of sepsis

There is legitimate interest in the effects of recombinant human activated protein C (rhAPC) on various organs and individual patients, but the specific effects on organ tissues during early sepsis remain unknown. Differences in the levels of organ damage may influence responses to drug therapy. We aimed to investigate whether rhAPC induces organ-specific effects on inflammation and apoptosis using randomized, experimental trials with male NMRI mice. Animals underwent caecal ligation and puncture, and after 12 h, sepsis inflammation and apoptosis were assessed by plasma cytokines, gene expression ratios and immunohistochemistry (IHC). RhAPC-treated animals exhibited increased physical activity and decreased cytokine release compared to untreated animals (interleukin-6 reduction 58%, P < 0.001). CD14 expression was higher in the heart and liver and decreased upon rhAPC application in the heart (−35%), liver and kidney (both −60%). Macrophage inflammatory protein 2 (MIP2) expression decreased in the heart (−58%) but not in the liver or kidney. IHC revealed decreased cleaved caspase-3 in the heart and kidney due to rhAPC intervention. Preservation of the endothelial PC receptor was significant only in the heart during sepsis ( P = 0.007). In early polymicrobial sepsis, inflammation was more pronounced in the heart and liver compared to the kidney. RhAPC exhibited protective effects, especially in the heart tissue, and led to reduced plasma levels of pro-inflammatory cytokines and improved physical activity.

Differential modulation of cord blood and peripheral blood monocytes by intravenous immunoglobulin

BACKGROUND

Immunoglobulins (IVIG) have been shown to be useful in adults suffering from sepsis. In contrast, prophylactic and curative IVIG trials failed to show beneficial effects in neonates. We tested the hypothesis that IVIG, have different effects on monocytes from cord blood (CBMO) and peripheral blood monocytes from adults (PBMO) with respect to survival, phenotype, and function.

METHODS

Mononuclear cells, or purified monocytes, were cultured in 5% human serum, incubated with polyvalent IVIG (1 mg/ml), stimulated with green fluorescent protein (GFP)-labeled Escherichia coli (E. Coli-GFP), Interferon-γ (IFN-γ, 50 U/ml), or the T cell mitogen anti-CD3 monoclonal antibody, αCD3-mAb, (5 μg/ml). Phagocytosis, phenotype, T cell proliferation, and apoptosis were assessed by flow cytometry.

RESULTS

IVIG enhanced phagocytosis in PBMO or CBMO when infected directly after isolation, while IVIG had no effect on monocytes cultured 48 h prior to infection. In contrast to PBMO, IVIG inhibited the IFN-γ mediated up-regulation of CD80, CD86, and HLA-DR on CBMO. In the presence of IVIG, stimulation with αCD3 in cord blood enhanced deletion, inhibited blast formation and CD28 up-regulation of T cells (P < 0.05 vs. T cells from adults). IVIG induced monocyte apoptosis, associated with up-regulation of Annexin V and loss of nuclear DNA, which was more pronounced in CBMO. Although phagocytosis induced cell death (PICD) was lower in CBMO (P < 0.05 vs. PBMO), the addition of IVIG enhanced PICD levels of CBMO to the extent of PBMO.

CONCLUSIONS

IVIG inhibits co-stimulatory receptors and functions of CBMO and induces apoptosis. These findings may be of clinical relevance for the failure of IVIG benefit in neonatal sepsis.

Phagocytosis and postphagocytic reaction of cord blood and adult blood monocyte after infection with green fluorescent protein-labeled Escherichia coli and group B Streptococci

BACKGROUND

Neonatal sepsis is characterized by an excessive inflammatory response induced by immune cells (monocytes). We investigated the initial stage of monocyte-pathogen interaction, i.e. bacterial ingestion and degradation at the single-cell level, by comparing a new flow cytometric procedure with culture methods. We also examined the hypothesis that, in terms of phagocytosis-induced cell death (PICD), phenotype, or cytokine production, cord blood monocytes (CBMO) differ from monocytes derived from adults (peripheral blood monocytes, PBMO).

METHODS

Phagocytosis and intracellular degradation were assessed by means of flow cytometry and bacterial cultures of green fluorescent protein-labeled group B Streptococci (GBS) and Escherichia coli. The production of reactive oxygen species (ROS) was measured through luminol-enhanced chemiluminescence. Apoptosis, phenotype, and cytokine production were assessed through flow cytometry.

RESULTS

Flow cytometry and bacterial cultures showed no difference between phagocytosis and degradation of GBS and E. coli by PBMO and CBMO. A high correlation between both methods was observed. No difference in ROS production was evident. In comparison with PBMO, CBMO apoptosis was lower after exposure to GBS and E. coli. Similarities were found between nonapoptotic monocytes and pro-inflammatory monocytes.

CONCLUSIONS

PICD is lower in CBMO during the early stages of monocyte-pathogen interaction. Our results emphasize that monocyte apoptosis has a potential role in tailoring the immune response in neonatal sepsis.

Suspension microarrays for the identification of the response patterns in hyperinflammatory diseases

Miniaturized and parallelized sandwich immunoassays allow the simultaneous analysis of a variety of parameters in a single experiment. Bead-based protein array systems or suspension microarrays are well-established multiplex sandwich immunoassay formats. To study inflammatory diseases, protein arrays can be used to analyze changes in plasma protein levels, such as cytokines, chemokines, soluble receptors, and matrix metalloproteinases. Using the bead-based Luminex system, multiplexed sandwich immunoassays have been developed to analyze the plasma concentrations of soluble receptors: sTNF-RI, sTNF-RII, sIL-2R, sgp130, sFas, sRAGE, sE-selectin, sICAM-1, sVCAM-1, sMIF-1 and sFasL. This newly established 11-plex soluble receptors assay demonstrated acceptable intra-assay and inter-assay precision, appropriate accuracy, and no crossreactivity between analytes. Using this assay, 100 plasma samples derived from 36 critically ill intensive care unit (ICU) patients with trauma or sepsis were analyzed for their soluble receptor plasma concentrations. Results obtained allowed grouping of patients' samples into a trauma and a sepsis group. Four candidate molecules: sFas, sICAM-1, sTNF-RI, and sTNF-RII had higher concentrations in patients with sepsis than in those with trauma, contributing the highest discriminatory values to define the nature of the inflammatory disease originating from pathogen-involved (sepsis) or pathogen-independent inflammation.

Pathogen specific cytokine release reveals an effect of TLR2 Arg753Gln during Candida sepsis in humans

Toll-like receptors (TLRs) are crucial pattern-recognition receptors (PRRs) for activation of innate and adapted immunity. TLR2 heterodimerizes with TLR1 or TLR6 to recognize multiple pathogen-associated molecular patterns (PAMPs) of fungi, Gram-positive pathogens, and mycobacteria. Receptor activation culminates in monocyte, T-helper (Th)1, and Th2 cytokine release. Single nucleotide polymorphisms (SNPs) Arg753Gln and Arg677Trp affect TLR2 responsiveness and may contribute to the course of sepsis, which is associated with substantial morbidity and mortality during intensive care treatment. We genotyped 325 critically ill patients with septic shock, and performed a detailed clinical follow-up with 47 of these patients. Here, we investigated whether distinct sepsis episodes result in defined plasma cytokine patterns, and whether cytokine profiles may be linked to the TLR2 polymorphisms. Blood sampling was done daily and microbiological testing was performed on a routine basis. DNA was extracted from whole blood and TLR2 SNPs were typed by pyrosequencing. Cytokines were measured by multiplexed array technologies and the leukocyte phenotype was determined by flow cytometry. Among the 325 ICU patients, 17 individuals (5.2%) were heterozygous for Arg753Gln. The SNP Arg677Trp was not found in any patient. Episodes of Gram-negative, Gram-positive, and Candida sepsis were recorded. During Gram-positive sepsis, the cytokine pattern did not differ between Arg753Gln heterozygous patients and wild type patients. By contrast, during Candida sepsis, the Arg753Gln heterozygous patients showed biomarker patterns that differed from wild type patients with elevated TNF-alpha plasma concentrations, but reduced IFN-gamma and IL-8 levels. In conclusion, TLR2 SNP Arg753Gln results in altered cytokine release in response to Candida but not to Gram-positive sepsis.