calcimycin and Crohn-Disease

Crohn's disease is associated with vascular injury and dysregulation of the intestinal immune system which together can provide disturbance of mesenteric circulation functional properties.. To evaluate the vascular reactivity of mesenteric arteries from patients with Crohn's disease.. Phenylephrine-induced contractions were assessed from 10 patients with Crohn's disease and 8 control organ donors. NG-nitro-L-arginine-methyl-ester (L-NAME) was used to test the presence of inducible NO synthase. Endothelium dependent and independent relaxation was assessed using acetylcholine, bradykinin, calcium ionophore A23187 and sodium nitroprusside.. The contractile response to phenylephrine was significantly decreased in arteries without endothelium from patients with Crohn's disease. Exposure to the NO synthase inhibitor L-NAME restored the contractile response to phenylephrine. Relaxation remained unaltered in both groups.. These data provide direct evidence for fading of contraction caused by phenylephrine in Crohn's disease. The restored mesenteric artery tone by a specific NO synthase inhibitor suggests that an increased production for NO in vascular smooth muscle might be responsible of this altered vascular reactivity.

Topics: Acetylcholine; Adult; Bradykinin; Calcimycin; Crohn Disease; Dose-Response Relationship, Drug; Female; Humans; In Vitro Techniques; Male; Mesenteric Arteries; Muscle Contraction; Muscle, Smooth, Vascular; Phenylephrine; Vasoconstrictor Agents; Vasodilator Agents

Recently, the immediate early gene h-sgk was cloned as a hypertonicity-induced gene from human hepatoma cells. The aim of this study was to localize h-sgk messenger RNA (mRNA) expression in normal and inflamed intestinal mucosa and to identify potential transcriptional regulators.. h-sgk mRNA in small intestinal mucosa from healthy persons and patients with Crohn's disease was determined by in situ hybridization. Transcriptional regulation was studied by Northern blot analysis of total RNA isolated from cultured human Intestine 407, U937, and HepG2 cells.. In normal ileum, h-sgk mRNA was selectively localized to the apical villus enterocytes, whereas no staining was detected in crypt cells. In Crohn's disease, enterocytes of the crypts expressed h-sgk and abundant h-sgk positive inflammatory cells appeared in the lamina propria. Combined h-sgk in situ hybridization and immunohistochemical analysis of CD68 antigen expression identified a part of these cells as macrophages. In addition to spatial correlation of transforming growth factor (TGF)-beta1 protein and h-sgk mRNA expression, h-sgk transcription in human Intestine 407 and HepG2 cells as well as in U937 monocytes/macrophages was strongly induced by TGF-beta1 in vitro.. h-sgk expression in normal and inflamed intestinal mucosa may be regulated by TGF-beta1 and may contribute to the pleiotropic actions of TGF-beta1 in mucosal cell populations.

Topics: Antigens, CD; Antigens, Differentiation, Myelomonocytic; Blotting, Northern; Calcimycin; Cells, Cultured; Crohn Disease; Cycloheximide; Gene Expression Regulation; Humans; Ileum; Immediate-Early Proteins; Immunohistochemistry; In Situ Hybridization; Inflammation; Interleukin-1; Intestinal Mucosa; Ionophores; Nuclear Proteins; Phorbol Esters; Protein Serine-Threonine Kinases; RNA, Messenger; Transcription, Genetic; Transforming Growth Factor beta; Tumor Necrosis Factor-alpha; U937 Cells

Colonic biopsy specimens from patients with active ulcerative colitis and controls were incubated for four hours in the presence or absence of calcium ionophore or antihuman immunoglobulin E (IgE). Platelet-activating factor (PAF) was determined in the tissue by aggregation assay after extraction with 80% ethanol. PAF was not detected in normal mucosa, whereas A23187 and antihuman IgE stimulated its activity: mean +/- SE, 43.2 +/- 8.6 and 33.0 +/- 6.1 pg/10 mg wet weight, respectively. In active ulcerative colitis, A23187 and antihuman IgE induced significantly higher stimulation of PAF synthesis compared to their effects on normal mucosa. The enhanced stimulation of PAF induced by A23187 was dose-dependently inhibited by sulphasalazine, 5-aminosalicylic acid and prednisolone, but not by sulfapyridine. Colonic interleukin-1 content and release during 24 h of culture were significantly higher in patients with active ulcerative colitis and Crohn's disease compared to normal subjects. Prednisolone significantly and dose-dependently inhibited interleukin-1 release. These results suggest that colonic generation of PAF and interleukin-1 are elevated in patients with inflammatory bowel disease and, thus, may have a role in its pathogenesis. Pharmacological suppression of colonic PAF and interleukin-1 production may have beneficial therapeutic effects.

Topics: Aminosalicylic Acids; Anti-Inflammatory Agents, Non-Steroidal; Antibodies, Anti-Idiotypic; Calcimycin; Colitis, Ulcerative; Colon; Crohn Disease; Humans; Imidazoles; Immunoglobulin E; Interleukin-1; Intestinal Mucosa; Mesalamine; Organ Culture Techniques; Platelet Activating Factor; Prednisolone; Sulfasalazine; Thiazoles

The metabolism of endogenous arachidonic acid P(AA) was investigated in activated neutrophils from 20 patients with Crohn's disease, 20 with ulcerative colitis, and 25 healthy volunteers. 1-14C-P(AA) was incorporated into intracellular pools of phospholipids prior to activation of the cells with ionophore A23187 and analyses of released arachidonic acid metabolites by thin layer chromatography. Total release of radioactivity expressing the release of arachidonic acid and its metabolites, was equal in the experimental and control groups, which suggests a normal substrate availability. In contrast, there was a marked increase in the relative release of leucotriene B4 (LTB4) and its omega-oxidation products, 20-hydroxy-LTB4 (20-OH-LTB4) and 20-carboxy-LTB4 (20-COOH-LTB4), with LTB4 values exceeding the reference interval in seven of 20 patients with Crohn's disease, median 8.7%, and in six of 20 patients with ulcerative colitis, median 7.7%, as compared with a median of 5.3% in healthy volunteers. Furthermore, a decreased release of unmetabolised arachidonic acid, correlating inversely with the release of LTB4 in all experimental and control groups, and normal values for the production of other metabolites of arachidonic acid--for example, 5-hydroxyeicosatetraenoic acid (5-HETE) and 12-hydroxyheptadecatrienoic acid (HHT), point to an enzymatic abnormality such as increased activity of leucotriene B synthetase. An increased capacity for release of LTB4, the major pro-inflammatory metabolite of arachidonic acid lipoxygenation by polymorphonuclear leucocytes, may contribute to perpetuation of the inflammation and to tissue destruction in chronic inflammatory bowel disease. Our findings agree with previous reports of an increased release of LTB4 by the colonic mucosa in this condition.

Topics: Adolescent; Adult; Arachidonic Acid; Arachidonic Acids; Calcimycin; Colitis, Ulcerative; Crohn Disease; Female; Humans; Hydroxyeicosatetraenoic Acids; Leukotriene B4; Male; Middle Aged; Neutrophils

Tissues of the gastrointestinal tract synthesize leukotriene (LT) B4 and the sulfidopeptide-leukotrienes LTC4, LTD4 and LTE4 from endogenous substrate. Formation of leukotrienes was demonstrated using radioimmunoassay, high pressure liquid chromatography (HPLC) and bioassay. Under basal conditions the gastrointestinal tissues released minor amounts of leukotrienes only. Formation of lipoxygenase-derived products of arachidonic acid metabolism was, however, significantly increased in the presence of various stimuli. Thus, significant amounts of LTB4 and of sulfidopeptide-leukotrienes were released from colonic and gastric mucosa of guinea-pigs sensitized against ovalbumin when incubations were carried out in the presence of antigen. Antigen-induced leukotriene formation was not found in the muscularis propria and subserosal of ovalbumin-sensitized guinea-pigs. Release of cyclooxygenase-derived metabolites of arachidonic acid, on the other hand, was most abundant in the subserosal layer of the guinea-pig colon and was not influenced by the immunological reaction. Inhibitors of cyclooxygenase, such as indomethacin, reduced gastrointestinal formation of prostaglandins, but not of leukotrienes. Inhibitors of 5-lipoxygenase, however, significantly decreased leukotriene formation. Synthesis of LTB4 and of sulfidopeptide-leukotrienes was also found in human colonic mucosal tissue, using the divalent cation-ionophore A23187 as stimulating agent. HPLC analysis demonstrated that the sulfidopeptide-leukotrienes released were composed of a mixture of LTC4, LTD4 and LTE4. In addition, human colonic mucosal tissue contained high activities of enzymes that rapidly convert LTC4 to LTE4. As in most biological systems LTE4 is less active than LTC4 and LTD4 degrading enzymes might represent a local inactivating mechanism. Mucosal tissue of patients with Crohn's disease synthesized considerably more LTB4 and sulfidopeptide-leukotrienes than non-inflamed mucosa.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animals; Arachidonate Lipoxygenases; Arachidonic Acid; Arachidonic Acids; Calcimycin; Chromatography, High Pressure Liquid; Colon; Crohn Disease; Cyclooxygenase Inhibitors; Dinoprostone; Guinea Pigs; Humans; Indomethacin; Intestinal Mucosa; Leukotriene B4; Lipoxygenase Inhibitors; Prostaglandins E; SRS-A