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Decreased serum iron concentration and total iron binding capacity are associated

Decreased serum iron concentration and total iron binding capacity are associated with serious Crohn’s disease

Jingling Su, Yandan Ren, Lupeng Liu, Yiqun Hu, Huaxiu Shi, Jianlin Ren, Chenxi Xie

Published in: Scientific reports, March 2022.

Abstract This study aimed to investigate whether serum indicators related to iron stores in the body are associated with clinical and endoscopic disease severity. Eighty-four patients with Crohn’s disease (CD) and twenty-four healthy volunteers were included. The indicators related to iron stores were detected within one week after endoscopic and CT enterography examinations. Patients were divided into three groups according to the CDAI(Crohn's disease activity index)scores. Serum iron levels were decreased in all groups (p < 0.05), and the values of remission group were higher than those of moderate group (p < 0.001). The total iron binding capacity(TIBC)values of the moderate group were lower than those of the controls and the other groups (p < 0.05). None of the indicators differed significantly among the patients classified by SES-CD (p > 0.05). Underweight, decreased serum iron and TIBC were independent risk factors for moderate clinical disease. Combined detection of decreased serum iron and TIBC was helpful in differentiating severe patients. The sensitivity and specificity were 32.7% and 100%, respectively (AUC = 0.812, p < 0.01). Decreases in serum iron and TIBC were associated with the clinical activity of CD. Combined detection of the two indicators was conducive to screening serious disease.

Introduction Patients with Crohn’s disease (CD) develop various extraintestinal complications. Iron deficiency can be encountered in 13%-90% of patients according to previous reports1,2. Iron deficiency plays a key role in affecting the quality of life of CD patients, resulting in symptoms, such as anemia, fatigue, sleep disorders, attention deficits and reduced functional capacity3,4. Factors leading to iron deficiency include bleeding, reduced iron absorption and immune regulation. Cytokines, such as IL-6 and TNF-a, can alter serum iron parameters by regulating the expression of hepcidin5,6,7. The production of active hepcidin by the liver is increased upon stimulation by cytokines from the inflamed bowel. Hepcidin can bind to the iron exporterferroportin1 on the basolateral membrane of enterocytes, leading to protein internalization and degradation8,9, this limits the efflux of iron to the plasma. Overload of iron content in enterocytes reduces the expression of duodenal cytochrome B (DcytB) and divalent metal transporter 1 (DMTI) on the brush border membrane, inhibiting dietary iron absorption9. Another important source of hepcidin is dendritic cells (DCs) in the gut10. In the absence of DC-derived hepcidin, iron can be released from macrophages and neutrophils to the lumen through ferroportin10. Basseri RJ et al. found that serum hepcidin was positively correlated with IL-6 and negatively correlated with hemoglobin in anemia of chronic disease (ACD)11.This suggested that iron stored in these inflammatory cells is an important source of hematopoiesis in CD patients with ACD. Although hepcidin is a key mediator of anemia in active CD patients, it is not tested routinely, partially because it may be difficult to distinguish active or inactive forms by commonly used immunoassays12. Semrin G et al. measured iron status in young CD patients. They showed that the level of serum iron and the total iron binding capacity were decreased in active CD patients due to impaired oral iron absorption8. Therefore, we hypothesized that the indicators related to serum iron parameters may be candidates for evaluating disease severity. Thus, the aims of the current study are (1) to compare the differences in serum indicators related to iron stores in the body between CD patients and controls and (2) to investigate whether these indicators are associated with disease severity.

Results Demographic characteristics of the patients A total of one hundred twenty-nine CD patients who were first admitted to our hospital were screened. Seventeen with a history of intestinal surgery and twenty-eight unable to tolerate endoscopy or CTE examination were excluded from this study. However, four who underwent laparoscopic appendectomy were included. Ultimately, eighty-four patients and twenty-four healthy volunteers were enrolled in the analysis


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