Dissociation between the functional activity and immunoreactive concentration of C1 esterase inhibitor in active and quiescent Crohn's disease

The role of the complement and contact systems in the dextran sulfate sodium-induced colitis model: the effect of C1 inhibitor in inflammatory bowel disease

The complement and contact systems may be involved in the pathophysiological process of inflammatory bowel disease (IBD). C1 inhibitor (C1INH) is the most important inhibitor of both the complement and contact systems. We evaluated the role of these systems and the effect of both active and inactive forms of C1INH (iC1INH) in dextran sulfate sodium (DSS)-induced colitis mouse model. Three percent DSS was used in drinking water to induce colitis in complement C3-deficient (C3(-/-)) mice, bradykinin type 2 receptor deficient (Bk(2)R(-/-)) mice, and C57BL/6 mice. After ten days DSS exposure, C3(-/-) mice exhibited markedly less weight loss than wild-type (WT) mice (12 +/- 3.3% vs. 30 +/- 1.2%, P < 0.05) and developed a milder disease-activity index (DAI), histological score, colon shortening, and myeloperoxidase (MPO) elevation (P < 0.05, respectively). The Bk(2)R(-/-) mice were not protected from the disease. Seven-day treatment with either native C1INH or iC1INH reduced the severity of the disease in WT mice, as indicated by decreased weight loss (15 +/- 1.8%, 14 +/- 2.1% vs. 30 +/- 1.2%, P < 0.05, respectively), DAI, intestinal tissue damage, and MPO elevation compared with untreated WT DSS control mice (P < 0.05, respectively). These findings suggest that complement plays a role in the development of DSS-induced colitis and that blockade of the complement system might be useful for the acute phase of IBD treatment. C1INH, however, leads to an amelioration of DSS-induced colitis via a mechanism that does not involve the inhibition of complement or contact system activation but does result in significant suppression of leukocyte infiltration.

Candidate-based proteomics in the search for biomarkers of cardiovascular disease

The key concept of proteomics (looking at many proteins at once) opens new avenues in the search for clinically useful biomarkers of disease, treatment response and ageing. As the number of proteins that can be detected in plasma or serum (the primary clinical diagnostic samples) increases towards 1000, a paradoxical decline has occurred in the number of new protein markers approved for diagnostic use in clinical laboratories. This review explores the limitations of current proteomics protein discovery platforms, and proposes an alternative approach, applicable to a range of biological/physiological problems, in which quantitative mass spectrometric methods developed for analytical chemistry are employed to measure limited sets of candidate markers in large sets of clinical samples. A set of 177 candidate biomarker proteins with reported associations to cardiovascular disease and stroke are presented as a starting point for such a 'directed proteomics' approach.

Kallikrein-kinin system activation in Crohn's disease: differences in intestinal and systemic markers

OBJECTIVES

Observations in experimental models and in human ulcerative colitis suggest that activation of the kallikrein-kinin system plays a role in the pathogenesis of inflammatory bowel disease. The aim of this study was to assess activation of the plasma and tissue kallikrein-kinin system in Crohn's disease.

METHODS

We studied plasma inflammatory and contact system parameters in 36 patients with Crohn's disease and in 36 control subjects with noninflammatory GI diseases. We also obtained tissue samples from the involved intestine of 12 patients with Crohn's disease, and from normal peritumoral tissue (12 patients) and diverticulitis tissue (seven patients) as controls. Full-thickness sections were tested for intestinal tissue kallikrein reactivity with a specific antibody.

RESULTS

In Crohn's disease patients and controls, plasma levels of prekallikrein, factor XI, high molecular weight kininogen and its cleaved form were normal. Crohn's disease patients had significantly higher levels of antigen and functional Cl-inhibitor (+22%, +12%) than did controls (p = 0.005, p = 0.004). After surgical resection, antigen and functional Cl-inhibitor significantly decreased in Crohn's disease patients (-22%, -15%; p = 0.035, p = 0.006). Intestinal tissue kallikrein immunoreactivity was absent (75%) or weak (25%) in the goblet cells from Crohn's disease tissue sections but was normal in controls, with a highly significant difference in the staining score (p = 0.0001). Intestinal tissue kallikrein immunoreactivity in the interstitium was higher in Crohn's disease than in normal and diverticulitis samples (p = 0.0001 and p = 0.001, respectively).

CONCLUSIONS

Our observations suggest that intestinal tissue kallikrein is involved in the inflammatory process in Crohn's disease. The lack of contact system activation in peripheral blood might be related to the high plasma levels of Cl-inhibitor, the most important inhibitor of the contact system in the circulation.

Coincidence of hereditary angioedema (HAE) with Crohn's disease

A patient with two diseases, based presumably on different immunopathological mechanisms, hereditary angioedema (HAE) and Crohn's disease, was followed for 8 years. For more than three years of this observation period, detailed laboratory data were also available and could be analyzed. Both diseases had severe courses requiring chronic treatment with danazol and sulfasalazine, respectively. During exacerbation of Crohn's disease, the levels of C4 was found to be significantly lower than during the periods free of symptoms of both diseases. This drop was probably due to an impaired C1-inhibitor activity. HAE attacks and acute exacerbation of Crohn's disease never occurred simultaneously. This finding may be a mere chance but may also indicate that the different immunopathological processes underlying HAE and Crohn's disease influence each other.