To investigate the relationship between serum concentrations of interleukin-8 (IL-8) and disease activity in inflammatory bowel disease, serum IL-8 concentrations were measured by enzyme-linked immunosorbent assay (ELISA) in 93 patients. Interleukin-8 levels were compared with plasma interleukin-6 (IL-6) levels in 80 of these patients. Interleukin-8 levels were also measured in ten patients with active Crohn's disease, before and after treatment with a defined formula polymeric diet. Of these patients, 70 out of 93 IL-8 concentrations were below the detection limit of the assay. Levels were higher in patients with active ulcerative colitis (median < 20 pg/mL, 75th centile value = 190) compared with inactive disease (median and 75th centile value < 20; P < 0.05). Interleukin-8 concentrations correlated with a combined score for disease severity and extent (P = 0.01). Thirty-eight per cent (8/20) of patients with active Crohn's disease also had high levels of IL-8 but there was no significant difference between active and inactive disease. There was no correlation between serum IL-8 and plasma IL-6; on the contrary, very few patients had raised blood levels of both cytokines. In the diet treated group, serum IL-8 fell significantly after treatment (median = 37 pg/mL, range < 20-4615 before treatment, median < 20, range < 20-104 after treatment; P = 0.03). The results suggest that although IL-8 may be involved in the inflammatory process in inflammatory bowel disease, it is a poor marker of disease activity.

Colitis, Ulcerative↗

PubMedDate not supplied

Expression of monocyte chemotactic protein and interleukin-8 by cytokine-activated human vascular smooth muscle cells.

The present study was designed to investigate the capacity of human vascular smooth muscle cells (SMCs) to produce a cytokine chemotactic for monocytes (monocyte chemotactic protein [MCP]) and by way of comparison, a related polypeptide activator of neutrophils (known as interleukin-8 [IL-8] or neutrophil activating protein-1 [NAP-1]. On exposure to IL-1, SMCs released high levels of chemotactic activity for monocytes, which could be removed by absorption with anti-MCP antibodies. MCP production by activated SMCs was comparable to that of IL-1-stimulated umbilical vein endothelial cells. Activated SMCs released appreciable levels of IL-8, as determined by a specific enzyme-linked immunosorbent assay, but little chemotactic activity for neutrophils. IL-1-treated SMCs expressed high levels of both MCP and IL-8 mRNA transcripts, as assessed by Northern blot analysis. Tumor necrosis factor and bacterial lipopolysaccharide but not IL-6 also induced MCP and IL-8 gene expression in SMCs. Nuclear runoff analysis revealed that IL-1 augmented transcription of the MCP and IL-8 genes. The capacity of SMCs to produce a cytokine (MCP) that recruits and activates circulating mononuclear phagocytes may be of considerable importance in the pathogenesis of vascular diseases (e.g., vasculitis and atherosclerosis) that are characterized by monocyte infiltration of the vessel wall.

Blotting, Northern↗

PubMedDate not supplied

Production of neutrophil activating peptide-1 (NAP-1/IL-8) by blood and synovial fluid mononuclear cells from patients with arthritis.

As polymorphonuclear leukocytes (PMN) are predominant in inflammatory synovial fluids, we investigated the production of neutrophil-activating peptide-1 (NAP-1) by mononuclear cells (MC) from 15 synovial fluids and matched peripheral blood. MC were cultured for 24 h alone or with stimulants (ConA, LPS). NAP-1 was determined in the supernatants by a bioassay (elastase release from normal human PMN) and an immunoassay (sandwich ELISA with a mouse anti-NAP-1 mAb and an alkaline phosphatase labelled goat anti-NAP-1 pAb). The results showed a significant increase in NAP-1 production by synovial fluid MC when compared to peripheral blood MC. Both cell types produced more NAP-1 in the presence of added stimuli. The results obtained with the two methods of detection were in close agreement. No relationship was found between the amount of NAP-1 produced in 24 h and the number of synovial fluid leukocytes, the erythrocyte sedimentation rate, the diagnosis of the underlying arthritis or the treatment of the patients.

Adult↗

PubMedDate not supplied

LPS and cytokine-induced endothelial cell IL-6 release and ELAM-1 expression; involvement of serum.

In this in vitro study, the influence of serum-concentration, heat inactivation of the serum and the origin of the serum on the responsiveness of cultured human umbilical vein endothelial cells (HUVEC) to immunological challenges was investigated. Addition of human serum during stimulation with 1 microgram/ml bacterial lipopolysaccharide (LPS) increased endothelial cell ELAM-1 expression and interleukin (IL)-6 release five to ten-fold. Full endothelial cell responsiveness to LPS required 10 to 50% human serum and was largely abrogated after heating the serum for 30 minutes at 56 degrees C. Addition of newborn or fetal bovine serum instead of human serum, induced even higher IL-6 release and ELAM-1 expression in response to LPS, whilst heat-inactivation of these serum-batches only moderately decreased endothelial cell responses. Endothelial cell IL-6 release and ELAM-1 expression after stimulation with IL-1 beta and tumor necrosis factor-alpha (TNF-alpha) were less influenced by heat inactivation of the serum and by omission of serum, whilst responses to PMA remained completely unaffected by such modifications in assay media. Finally, we demonstrated that endothelial cell IL-8 release also and ICAM-1 expression in response to LPS and cytokines were increased by addition of human serum, indicating that the use of serum-free assay media, or the use of media enriched with heat-inactivated (HI) human serum interferes with physiological endothelial cell responsiveness.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMedDate not supplied

IL-6, IL-8 and TNF production by cytokine and lipopolysaccharide-stimulated human renal cortical epithelial cells in vitro.

The capacity of renal epithelial cells to produce IL-6, IL-8 and TNF was investigated. Cultures of explanted human renal cortical epithelial cells (RCEC) were established, and cytokine-release and mRNA expression by these cells were measured. IL-6, IL-8 and TNF release were measured after stimulation with IL-1 beta TNF-alpha, LPS and the phorbol esther PMA. All these agents were found to induce increased release of the three cytokines. Whilst no spontaneous TNF-release occurred, IL-6 and IL-8 were continuously released by non-stimulated RCEC cultures. IL-1 beta was the most potent trigger, enhancing both RCEC cytokine release and expression of IL-6, IL-8 and TNF mRNA. Indomethacin, budesonide, cyclosporin and FK 506 were tested for their influence on RCEC cytokine release. Only the steroid budesonide appeared to reduce both spontaneous and IL-1 beta induced cytokine release. Our data demonstrate stimulus specific release of IL-6, IL-8 and TNF by RCEC, and suggest that cytokine cell-to-cell communication may be important in regulating inflammatory processes in the kidney.

Budesonide↗