Dunlop Simon P, Jenkins David, Spiller Robin C
Division of Gastroenterology, University Hospital, Nottingham, NG7 2UH, UK.
Eur J Gastroenterol Hepatol. 2004 Oct;16(10):1011-5. doi: 10.1097/00042737-200410000-00010.
Previous studies have shown that irritable bowel syndrome declines with age and is more common in women. Recent reports suggest that some diarrhoea predominant irritable bowel syndrome patients have low-grade inflammation with increased numbers of mucosal T lymphocytes, 5-hydroxytryptamine (5-HT) containing enteroendocrine cells and mast cells.
To determine whether there are age or gender-related changes in mucosal T lymphocytes, mast cells or enteroendocrine cells which might explain these findings.
Forty healthy volunteers (20 subjects below 55 years of age and 20 above 55 years) free from gastro-intestinal symptoms or disease answered detailed bowel symptom questionnaires and underwent sigmoidoscopy, rectal biopsy and colonic transit measurement. Biopsies were immunostained and quantified for lamina propria and intra-epithelial T lymphocytes, mast cells and 5-HT and peptide YY enteroendocrine cells.
There was a reduction in lamina propria T lymphocyte counts (P = 0.018), crypt intra-epithelial T lymphocytes (P = 0.014) and mast cells (P = 0.02) in the > 55 year group. Enteroendocrine cell numbers did not decline with age and were not related to colonic transit. There were no gender differences between any of the cells quantified.
Lymphocyte and mast cell numbers decline with age in normal large bowel mucosa. Reduced numbers of mucosal inflammatory cells may influence the low-grade inflammatory response to luminal antigens and contribute to the reduction of irritable bowel syndrome observed in older subjects.
既往研究表明，肠易激综合征的发病率随年龄增长而下降，且在女性中更为常见。近期报告显示，一些腹泻型肠易激综合征患者存在低度炎症，黏膜T淋巴细胞、含5-羟色胺（5-HT）的肠内分泌细胞和肥大细胞数量增加。
确定黏膜T淋巴细胞、肥大细胞或肠内分泌细胞是否存在与年龄或性别相关的变化，从而解释上述发现。
40名无胃肠道症状或疾病的健康志愿者（20名年龄在55岁以下，20名年龄在55岁以上）回答了详细的肠道症状问卷，并接受了乙状结肠镜检查、直肠活检和结肠转运测量。对活检组织进行免疫染色，并对固有层和上皮内T淋巴细胞、肥大细胞、5-HT和肽YY肠内分泌细胞进行定量分析。
55岁以上组的固有层T淋巴细胞计数（P = 0.018）、隐窝上皮内T淋巴细胞（P = 0.014）和肥大细胞（P = 0.02）数量减少。肠内分泌细胞数量不随年龄下降，且与结肠转运无关。在任何定量分析的细胞中均未发现性别差异。
正常大肠黏膜中淋巴细胞和肥大细胞数量随年龄增长而减少。黏膜炎症细胞数量减少可能影响对腔内抗原的低度炎症反应，并导致老年受试者肠易激综合征发病率降低。
