Diagnosing anemia in inflammatory bowel disease: Beyond the established markers

The main types of anemia in inflammatory bowel disease (IBD) are iron deficiency anemia (IDA) and anemia of inflammatory etiology, or anemia of chronic disease (ACD). In the management of IBD patients with anemia it is essential for the physician to diagnose the type of anemia in order to decide in an evidence-based manner for the appropriate treatment. However, the assessment of iron status in IBD in many cases is rather difficult due to coexistent inflammation. For this assessment several indices and markers have been suggested. Ferritin, seems to play a central role in the definition and diagnosis of anemia in IBD and transferrin, transferrin saturation (Tsat), and soluble transferrin receptors are also valuable markers. All these biochemical markers have several limitations because they are not consistently reliable indices, since they are influenced by factors other than changes in iron balance. In this review, in addition to them, we discuss the newer alternative markers for iron status that may be useful when serum ferritin and Tsat are not sufficient. The iron metabolism regulators, hepcidin and prohepcidin, are still under investigation in IBD. Erythrocytes parameters like the red cell distribution width (RDW) and the percentage of hypochromic red cells as well as reticulocyte parameters such as hemoglobin concentration of reticulocytes, red blood cell size factor and reticulocyte distribution width could be useful markers for the evaluation of anemia in IBD.     

Update of fecal markers of inflammation in inflammatory bowel disease

The diagnosis, prognosis, and assessment of disease activity of inflammatory bowel disease (IBD) require investigating clinical, radiological, and histological criteria, as well as serum inflammatory markers. However, a range of fecal inflammatory markers now appears to have the potential to greatly assist in these processes. Calprotectin, a prominent neutrophil protein, was identified two decades ago as a potentially revolutionary marker for IBD. Following this discovery, numerous additional markers, including S100A12, lactoferrin, and M2-pyruvate kinase, have also been suggested as novel markers of IBD. In the present study, we provide an up-to-date review of fecal markers of IBD, and further, provide a novel analysis of each of these fecal markers in severe ulcerative colitis and compare their expression pattern in contrast to calprotectin.     

Established and emerging biological activity markers of inflammatory bowel disease

Assessment of disease activity in inflammatory bowel disease (IBD), i.e., ulcerative colitis (UC) and Crohn's disease (CD), is done using clinical parameters and various biological disease markers. Ideally, a disease marker must: be able to identify individuals at risk of a given disorder, be disease specific, mirror the disease activity and, finally, be easily applicable for routine clinical purposes. However, no such disease markers have yet been identified for IBD. In this article, classical disease markers including erythrocyte sedimentation rate, acute phase proteins (especially orosomucoid and CRP), leukocyte and platelet counts, albumin, neopterin, and beta2-microglobulin will be reviewed together with emerging disease markers such as antibodies of the ANCA/ASCA type, cytokines (e.g., IL-1, IL-2Ralpha, IL-6, IL-8, TNF-alpha, and TNF-alpha receptors) and with various adhesion molecules. It is concluded that none of the pertinent laboratory surrogate markers of disease activity in IBD are specific or sensitive enough to replace basic clinical observation such as the number of daily bowel movements, general well-being, and other parameters in parallel. Further studies are highly warranted to identify and assess the clinical importance and applicability of new laboratory markers for the diagnosis or the disease activity of IBD.     

Surrogate markers of intestinal inflammation are predictive of relapse in patients with inflammatory bowel disease

BACKGROUND & AIMS: Prediction of relapse of inflammatory bowel disease has important implications for therapeutic strategies. We assessed whether measurement of intestinal permeability and inflammation could predict relapse of inflammatory bowel disease (IBD). METHODS: Forty-three patients with Crohn's disease (CD) and 37 with ulcerative colitis (UC) in clinical remission provided a stool sample to be assayed for calprotectin (a neutrophil-specific marker), and patients with CD additionally underwent a small intestinal permeability test. Relapse was defined using clinical disease activity indices. RESULTS: Twenty-five (58%) patients with CD and 19 (51%) with UC had a relapse over the 12-month period. Median calprotectin levels in the relapse groups (122 mg/L for CD, 123 mg/L for UC; normal <10 mg/L) differed significantly (P<0.0001) from those of the nonrelapse groups (41.5 mg/L for CD, 29.0 mg/L for UC). At 50 mg/L, the sensitivity and specificity of calprotectin for predicting relapse in all patients with IBD were 90% and 83%, respectively. Permeability in the CD patients who relapsed (median, 0.075; normal <0.04) differed significantly (P = 0. 004) from that in the nonrelapse group (median, 0.038). At the level of 0.05, the sensitivity and specificity of permeability in predicting relapse were 84% and 61%, respectively. CONCLUSIONS: Fecal calprotectin predicts clinical relapse of disease activity in patients with CD and UC, whereas small intestinal permeability is a useful predictor of relapse in patients with small intestinal CD.     

Neutrophil gelatinase-associated lipocalin is expressed in osteoarthritis and forms a complex with matrix metalloproteinase 9

OBJECTIVE: Expression of matrix metalloproteinase 9 (MMP-9) is up-regulated in osteoarthritis (OA) and usually presents as multiple bands when synovial fluid (SF) from OA patients is analyzed by zymography. Among these bands is an approximately 125-130-kd band for high molecular weight (HMW) gelatinase, which has not been characterized. This study was undertaken to characterize the HMW MMP activity in OA SF. METHODS: MMP activity in OA SF was determined by gelatin zymography. Recombinant MMPs were used to identify MMP activity on the zymogram. Western immunoblotting, immunoprecipitation, and immunodepletion analyses were performed using antibodies specific for human MMP-9 and human neutrophil gelatinase-associated lipocalin (NGAL). Human cartilage matrix degradation was determined by dimethylmethylene blue assay. RESULTS: Zymographic analysis showed that the HMW gelatinase in OA SF comigrated with a purified NGAL-MMP-9 complex. Results of Western immunoblotting showed that the HMW gelatinase was also recognized by antibodies specific for human NGAL or human MMP-9. These same antibodies also immunoprecipitated the HMW gelatinase activity from OA SF. The NGAL-MMP-9 complex was reconstituted in vitro in gelatinase buffer. In the presence of NGAL, MMP-9 activity was stabilized; in the absence of NGAL, rapid loss of MMP-9 activity occurred. MMP-9-mediated release of cartilage matrix proteoglycans was significantly higher in the presence of NGAL (P < 0.05). CONCLUSION: Our findings demonstrate that the HMW gelatinase activity in OA SF represents a complex of NGAL and MMP-9. The ability of NGAL to protect MMP-9 activity is relevant to cartilage matrix degradation in OA and may represent an important mechanism by which NGAL may contribute to the loss of cartilage matrix proteins in OA.     

炎症性肠病的生物学活性标志物的研究进展

随着诊疗手段的日益进步,炎症性肠病(inflam matory bowel disease,IBD)发病率近年来呈逐年上升趋势.然而由于临床表现复杂多样,不仅有消化道症状,还可有肠外表现,并且缺乏特异性指标,IBD诊断容易误诊,且评估疾病活动性也较困难.放射学,内镜及组织学活检都为诊断及评估提供了方法,但这些方法受射线、有创性、昂贵等缺点限制.目前临床上需要一种简单、无创、敏感、经济、特异性强、在临床上易推广的方法来应用于对IBD的诊断及活动性的判定,因此生物活性标志物被大量研究.本文从鉴别溃疡性结肠炎(ulcerative colitis)和克罗恩病(Crohn's disease)及反应炎症的存在或程度两方面就临床有适用性的生物学活性标志物的研究进行了综述.     

Fecal markers of inflammation used as surrogate markers for treatment outcome in relapsing inflammatory bowel disease

AIM： To evaluate fecal calprotectin （FC） as a surrogate marker of treatment outcome of relapse of inflammatory bowel disease （IBD） and, to compare FC with fecal myeloperoxidase （MPO） and fecal eosinophil protein X （EPX）.
METHODS： Thirty eight patients with IBD, comprising of 27 with ulcerative colitis （UC） and 11 with Crohn＇s disease （CD） were investigated before treatment （inclusion）, and after 4 and 8 wk of treatment. Treatment outcomes were evaluated by clinical features of disease activity and endoscopy in UC patients, and disease activity in CD patients. In addition, fecal samples were analyzed for FC by enzyme-linked immunosorbent assay （ELISA）, and for MPO and EPX with radioimmunoassay （RIA）.
RESULTS： At inclusion 37 of 38 （97%） patients had elevated FC levels （〉 94.7 μg/g）. At the end of the study, 31 of 38 （82%） patients fulfilled predefined criteria of a complete response IUC 21/27 （78%）; CD 10/11 （91%）]. Overall, a normalised FC level at the end of the study predicted a complete response in 100% patients, whereas elevated FC level predicted incomplete response in 30%. Normalised MPO or EPX levels predicted a complete response in 100% and 90% of the patients, respectively. However, elevated MPO or EPX levels predicted incomplete response in 23% and 22%, respectively.
CONCLUSION： A normalised FC level has the potential to be used as a surrogate marker for successful treatment outcome in IBD patients. However, patients with persistent elevation of FC levels need further evaluation. FC and MPO provide superior discrimination than EPX in IBD treatment outcome.     

Neutrophil chemokines GCP-2 and GRO-alpha in patients with inflammatory bowel disease

OBJECTIVE: To measure the serum levels of neutrophils chemokine granulocyte chemotactic protein‐2 (GCP‐2) and interleukin‐8 (IL‐8) in Crohn's disease (CD) and ulcerative colitis (UC) patients and compare them with serum levels of growth‐related oncogene (GRO‐α). METHODS: Forty‐two patients with inflammatory bowel disease (24 CD and 18 UC) and 38 matched healthy subjects were recruited. Their serum GCP‐2, IL‐8 and GRO‐α were measured by a specific enzyme immunoassay kit. RESULTS: The serum levels of GCP‐2 were significantly higher in the CD than the UC patients but lower than in the healthy subjects. The GCP‐2 in the UC patients were significantly lower than in the healthy subjects. The GRO‐α levels were significantly higher in the IBD patients than in the healthy subjects. The IL‐8 levels were under the detectable limit in both the IBD and the healthy subjects. CONCLUSION: In this group of patients, GCP‐2 did not participate in the inflammatory response in IBD. GRO‐α could be an important factor that enhances the inflammatory state in IBD.     

Neutrophil aldose reductase activity and its association with established diabetic microvascular complications.

Direct investigation of the polyol pathway is rarely possible in studies of human diabetes. A spectrophotometric assay has been developed for the measurement of aldose reductase and sorbitol dehydrogenase activity in the neutrophil. Neutrophil aldose reductase activity was increased in patients with Type 1 diabetes with complications (median 40 (interquartile range 28-48) u, where 1 unit of enzyme activity = nmol NADPH min-1 10(8)-cells-1) compared with those without complications (20 (16-36) u, p less than 0.01) and normal control subjects (20 (8-36) u, p less than 0.01). In Type 2 diabetes, patients with complications also had higher aldose reductase activity (40 (28-52) u) than those without complications (24 (16-36) u, p less than 0.01). There were no differences between patients without complications and normal control subjects. Sorbitol dehydrogenase activity was decreased in diabetic patients (p less than 0.02) but not significantly different between diabetic patients with and without complications.     

Nutrition and inflammatory bowel disease: its relation to pathophysiology, outcome and therapy

Nutritional deficiencies are frequent in patients with ulcerative colitis and Crohn's disease, and negatively influence the outcome of the disease. Growth retardation, osteopenia and thromboembolic phenomena are some of the inflammatory bowel disease complications in which nutritional deficits are involved. Moreover, nutrients can play a role in the pathogenesis of the disease and, in some cases, can be a primary therapeutic tool. Enteral nutrition has proven to play a therapeutic role in Crohn's disease. The nutrient(s) responsible for this effect are not well identified but dietary fat appears to be a major factor. In ulcerative colitis, unabsorbable carbohydrates can modulate the intestinal microbial environment, thus contributing to improve colonic inflammation.     

Role of biological markers in inflammatory bowel disease

The role played by the distinct biological markers in chronic inflammatory bowel disease (IBD) remains insufficiently characterized. C-reactive protein (CRP) has a short half-life and consequently it is elevated early after the onset of the inflammatory process and rapidly decreases after its resolution, making it an attractive marker of disease activity. Moreover, this test is inexpensive and easy to perform and is unaffected by medication. While Crohn's disease is associated with a marked CRP response, there is little or no elevation in the synthesis of this protein in ulcerative colitis. Erythrocyte sedimentation rate provides some advantages such as its ease of determination, availability, and reduced cost. Nevertheless, it also has several disadvantages, notably the fact that its concentration depends on age, the presence of anemia, smoking, and the use of certain drugs. Moreover, its utility is limited by its long half life and consequent prolonged latency period after changes in chronic IBD activity. In theory, fecal markers have the advantages of showing greater specificity in the diagnosis of chronic IBD. Several gastrointestinal diseases, including chronic IBD, show greater leukocyte elimination in feces and a close correlation has been described between fecal calprotectin concentration and leukocyte excretion quantified by 111indium. Advantages of this fecal marker are that it can be detected through a simple and inexpensive technique and also shows excellent stability in feces for prolonged periods. Like calprotectin, fecal lactoferrin is also quantified by a simple and inexpensive ELISA method, although there is considerably less experience with this latter marker.     

Signaling for inflammation and repair in inflammatory bowel disease

In patients with inflammatory bowel diseases (IBD) the immune system leads to the polarization of intestinal immune cells towards a T helper one (Th1) pro-inflammatory response. The immunologic factors intervene in intestinal homeostasis and initiate the development of intestinal mucosal inflammation. Cytokines, which are important regulators of inflammation and repair as wells as leukocyte trafficking have become apparent as key immune molecules in the pathogenesis of IBD. In this review, recent advances in our understanding of the cytokine involvement in inflammation and repair in patients with ulcerative colitis (UC) and Crohn's disease (CD) are discussed. Knowledge of objective evidence of inflammatory activity may allow targeted treatment at an earlier stage to avoid the relapse, as well as assessment of new therapeutic strategies for maintenance of remission.     

Gut lavage fluid proteins as markers of activity of inflammatory bowel disease

Intestinal secretions may be obtained by gut lavage using a polyethyleneglycol-based electrolyte lavage solution; concentrations of immunoglobulins and other proteins are readily measured in processed gut lavage fluid. As patients with inflammatory bowel disease (IBD) have greatly increased numbers of IgG-producing intestinal immunocytes, we measured gut lavage fluid IgG levels in 44 patients with IBD with various degrees of disease activity to determine whether total IgG in gut lavage fluid reflects disease activity. We also measured levels of albumin in gut lavage fluid, to determine the degree of plasma leakage. Both IgG and albumin levels in the patients with active IBD were significantly higher than those in controls and patients with inactive IBD (all p less than 0.00001). IgG is a more specific index of disease activity than albumin, with no overlap between levels in controls and patients with active IBD. There was a positive correlation (r = 0.68, p less than 0.0001) between IgG and albumin levels, suggesting that gut lavage fluid IgG is mainly plasma-derived.     

New serological markers in pediatric patients with inflammatory bowel disease

The spectrum of serological markers associated with inflammatory bowel disease(IBD)is rapidly growing.Due to frequently delayed or missed diagnoses,the application of non-invasive diagnostic tests for IBD,as well as differentiation between ulcerative colitis(UC)and Crohn’s disease(CD),would be useful in the pediatric population.In addition,the combination of pancreatic autoantibodies and antibodies against Saccharomyces cerevisiae antibodies/perinuclear cytoplasmic antibody(pANCA)improved the sensitivity of serological markers in pediatric patients with CD and UC.Some studies suggested that age-associated differences in the patterns of antibodies may be present,particularly in the youngest children.In CD,most patients develop stricturing or perforating complications,and a significant numberof patients undergo surgery during the disease course.Based on recent knowledge,serum antibodies are qualitatively and quantitatively associated with complicated CD behavior and CD-related surgery.Pediatric UC is characterized by extensive colitis and a high rate of colectomy.In patients with UC,high levels of antiCBir1 and pANCA are associated with the development of pouchitis after ileal pouch-anal anastomosis.Thus,serologic markers for IBD can be applied to stratify IBD patients into more homogeneous subgroups with respect to disease progression.In conclusion,identification of patients at an increased risk of rapid disease progression is of great interest,as the application of early and more aggressive pharmaceutical intervention could have the potential to alter the natural history of IBD,and reduce complications and hospitalizations.     

Serological markers in inflammatory bowel disease: the pros and cons

Accurate serological assays are desirable for the diagnosis of inflammatory bowel disease. Among several serological markers anti-Saccharomyces cerevisiae mannan antibodies and perinuclear antineutrophil cytoplasmic autoantibodies are highly disease specific for Crohn's disease and ulcerative colitis, respectively. Combining the two improves their specificity. Sensitivity, however, is still low. Due to lack of standardization and vast interobserver variability, they cannot be used as the only diagnostic criteria but can assist clinicians in diagnosing and categorizing patients with inflammatory bowel disease as well as in helping them to take therapeutic decisions.