RESUMEN
BACKGROUND: Bacteria are implicated as important factors in the pathogenesis of inflammatory bowel disease (IBD). The aim of this study was to seek evidence of possible bacterial targets of the immune response related to IBD in children. METHODS: Seventy-eight children referred to the Department of Paediatrics at Tampere University Hospital on suspicion of IBD were included in the study. Upper and lower gastrointestinal endoscopies with biopsies were performed on all children. Sera from 75 children were tested for antibodies to the Pseudomonas fluorescens-associated sequence I2, a Bacteroides caccae TonB-linked outer membrane protein, OmpW, anti-Saccharomyces cerevisiae, and perinuclear anti-neutrophil cytoplasmic antibodies. RESULTS: The IBD diagnosis was confirmed in 35 children (18 with Crohn's disease [CD], 12 with ulcerative colitis [UC], and 5 with indeterminate colitis [IC]); 43 children were found to have no inflammation in the gut. Forty-three percent (15 of 35) of those with IBD evinced positive seroreactivity to I2 and 46% (16 of 35) to OmpW. In CD, seroreactivity to I2 and OmpW was 50% (9 of 18) and 61% (11 of 18), respectively. Serum anti-I2 and anti-OmpW immunoglobulin A levels were significantly elevated in children with CD in comparison with the non-IBD group (P = 0.007 and P = 0.001, respectively). A combination of OmpW, I2, and anti-S cerevisiae tests identified 94% of CD patients, and a combination of OmpW, I2, and perinuclear anti-neutrophil cytoplasmic antibodies detected 83% of UC cases. CONCLUSIONS: Among children with IBD, strong serological responses to microbial antigens can be found, suggesting that P fluorescens and B caccae antigens have a potential role in the microbiology and immunology of the disease. Furthermore, serologic reactivity to the set of antigens studied here seems to be applicable in the initial differential diagnosis of children with CD and UC.
Asunto(s)
Anticuerpos/sangre , Proteínas de la Membrana Bacteriana Externa/inmunología , Enfermedades Inflamatorias del Intestino/inmunología , Superantígenos/inmunología , Adolescente , Niño , Preescolar , Humanos , Enfermedades Inflamatorias del Intestino/sangreRESUMEN
OBJECTIVE: In coeliac disease, autoantibodies directed against transglutaminase 2 are produced in small-bowel mucosa, and they have been found to be deposited extracellularly. The aim of this study was to investigate whether such mucosal IgA deposits are important in the diagnostic work-up of early-stage coeliac disease without small-bowel mucosal villous atrophy. MATERIAL AND METHODS: Forty-one adults suspected of coeliac disease owing to increased density of mucosal gamma(delta)+ intraepithelial lymphocytes but normal villous morphology were randomized to gluten challenge or a gluten-free diet for 6 months. Clinically and histologically verified gluten dependency was compared with existence of small-bowel mucosal transglutaminase 2-specific extracellular IgA deposits and (coeliac disease-type) HLA DQ2 and DQ8; 34 non-coeliac subjects and 18 patients with classical coeliac disease served as controls. RESULTS: Of the 41 patients, 5 in the challenge group and 6 in the gluten-free diet group were clinically gluten sensitive; all 11 had HLA DQ2 or DQ8. Ten of these 11 patients showed transglutaminase 2-targeted mucosal IgA deposits, which were dependent on gluten consumption. Minimal IgA deposits were seen in only 3 out of 30 patients with suspected coeliac disease without any clinically detected gluten dependency. The deposits were found in all classical coeliac patients and in none of the non-coeliac control subjects. CONCLUSIONS: Clinically pertinent coeliac disease exists despite normal small-bowel mucosal villous architecture. Mucosal transglutaminase 2-specific IgA deposits can be utilized in detecting such patients with genetic gluten intolerance.
Asunto(s)
Enfermedad Celíaca/diagnóstico , Proteínas de Unión al GTP/metabolismo , Glútenes/administración & dosificación , Inmunoglobulina A/análisis , Mucosa Intestinal/metabolismo , Transglutaminasas/metabolismo , Adulto , Enfermedad Celíaca/dietoterapia , Enfermedad Celíaca/inmunología , Femenino , Proteínas de Unión al GTP/inmunología , Antígenos HLA-DQ/análisis , Humanos , Mucosa Intestinal/inmunología , Intestino Delgado/patología , Linfocitos/metabolismo , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Proteína Glutamina Gamma Glutamiltransferasa 2 , Transglutaminasas/inmunologíaRESUMEN
BACKGROUND: Bisphosphonates reduce the bone metastasis formation and angiogenesis but the exact molecular mechanisms involved are unclear. Progelatinase A (proMMP-2; 78 KDa) is activated up during the tumor spread and metastasis by a cell surface-associated matrix metalloproteinase (membrane-type matrix metalloproteinase [MT1-MMP] or MMP-14). MATERIAL AND METHODS: We evaluated the effects of a bisphosphonate (clodronate) on MT1-MMP mRNA expression and protein production, catalytic activity and proteolytic activation of proMMP-2 by cultured human MG-63 osteosarcoma cells. RESULTS: Clodronate, at therapeutically attainable noncytotoxic concentrations, dose-dependently inhibited phorbol myristic acetate (PMA)-induced proteolytic activation of proMMP-2 by human MG-63 osteosarcoma cells. Clodronate also downregulated the PMA-induced expression of MT1-MMP mRNA and protein production in human MG-63 osteosarcoma cells, as evidenced by Northern analysis and fluorescent immunohistochemistry. Furthermore, clodronate inhibited directly and dose-dependently MT1-MMP activity, and the MT1-MMP inhibition by clodronate was reduced in the presence of an increased (5 mM) Ca(2+) concentrations when compared to physiological (1 mM) Ca(2+) concentrations. CONCLUSION: We conclude that (1) the extracellular/cell-associated mechanism of bisphosphonate involves inhibition of MT1-MMP catalytic activity eventually by chelation, and that (2) intracellular mechanism involves downregulation of induced MT1-MMP mRNA and protein expression. The inhibition and downregulation of MT1-MMP by clodronate can be related to their ability to reduce MG-63 osteosarcoma cell invasion and spread. These findings may, at least in part, explain at molecular level the antitumor and antibone resorption activities of clodronate observed in clinical studies.
Asunto(s)
Ácido Clodrónico/farmacología , Inhibidores Enzimáticos/farmacología , Metaloendopeptidasas/antagonistas & inhibidores , Osteosarcoma/enzimología , Sitios de Unión/efectos de los fármacos , Northern Blotting , Colagenasas/biosíntesis , Medios de Cultivo Condicionados , Activación Enzimática/efectos de los fármacos , Precursores Enzimáticos/metabolismo , Técnica del Anticuerpo Fluorescente , Gelatinasas/metabolismo , Humanos , Metaloproteinasa 13 de la Matriz , Metaloproteinasa 2 de la Matriz/biosíntesis , Metaloproteinasa 2 de la Matriz/genética , Metaloproteinasas de la Matriz Asociadas a la Membrana , Metaloendopeptidasas/genética , Metaloendopeptidasas/metabolismo , ARN Mensajero/análisis , Proteínas Recombinantes , Acetato de Tetradecanoilforbol/farmacología , Células Tumorales CultivadasRESUMEN
Recent studies have implicated a crucial role for tissue transglutaminase (TG2) in the pathogenesis of Celiac Sprue, a disorder of the small intestine triggered in genetically susceptible individuals by dietary exposure to gluten. Proteolytically stable peptide inhibitors of human TG2 were designed containing acivicin or alternatively 6-diazo-5-oxo-norleucine (DON) as warheads. In biochemical and cell-based assays, the best of these inhibitors, Ac-PQP-(DON)-LPF-NH(2), was considerably more potent and selective than other TG2 inhibitors reported to date. Selective pharmacological inhibition of extracellular TG2 should be useful in exploring the mechanistic implications of TG2-catalyzed modification of dietary gluten, a phenomenon of considerable relevance in Celiac Sprue.