EFFECT OF FAT AND FIBER ON COLONIC INTESTINAL EPITHELIAL CELLS

结肠癌是一种常见的人类恶性肿瘤。 膳食脂肪和纤维 会影响结直肠癌的发病率。 人口 高脂肪低纤维的饮食， 结直肠癌的发病率，与消费 少脂肪多纤维 目前还不完全清楚膳食脂肪和 纤维是结肠癌发生的独立变量。 丁酸钠是一种短链脂肪酸， 大量的膳食纤维被结肠细菌发酵。 丁酸钠在体外抑制细胞增殖并诱导细胞凋亡 在培养的结肠癌细胞中。 本研究考察了 不同水平的膳食脂肪和纤维对增殖和死亡的影响 结肠上皮细胞。 受试者的饮食控制良好 （体重维持，代谢），脂肪/纤维组合（高，正常 或低脂肪和高、正常或低纤维）作为自变量。 入院时，基线内镜活检后（通过灵活的 乙状结肠镜检查），受试者接受低脂肪、高纤维饮食4 wks. 结肠上皮、丁酸钠和Ki-ras的评估 通过内窥镜活检、血液和粪便进行癌基因突变检查 样品 在1995年1月12日至1996年11月30日的资助期间， 完成了研究。 两名受试者均接受高纤维/低脂饮食， 30天（21.5%脂肪P/S比1.5，15.4%蛋白质，63.2% CHO，47 g膳食 纤维/2400 Cal）。 两名受试者都能耐受研究和手术 无事件参与。 所有受试者均进行了多次结肠活检 没有困难或副作用。没有明确的 科学研究报告在这个时候。 然而，一些重要的 从这些研究中可以得出一般性结论。 第一，多个 每周一次的乙状结肠镜检查可以安全地进行 志愿者在4周内的不良反应最小，如果有的话。 有 对结肠粘膜的显微结构没有重大影响， 多次重复粘膜活检。 有早期迹象表明， 2个受试者的纯定性数据表明，饮食中的高纤维会影响 结肠粘膜中细胞凋亡的程度。

Colon cancer is a common human malignancy. Dietary fat and fiber have been shown to affect the incidence of colorectal cancer. Populations consuming diets high in fat and low in fiber overall have greater incidence rates of colorectal cancer, compared to populations consuming less fat and more fiber. It is not entirely clear whether dietary fat and fiber are independent variables with respect to colon carcinogenesis. Sodium butyrate, a short chain fatty acid, is generated in the colon in large quantities as dietary fiber is fermented by colonic bacteria. Sodium butyrate, in vitro, reduces the proliferation and induces apoptosis in cultured colon cancer cells. This research examines the effect of different levels of dietary fat and fiber on the proliferation and death of colonic epithelial cells. Subjects are given a well-controlled diet (weight maintaining, metabolic), with fat/fiber combination (high, normal or low fat and high, normal or low fiber) as the independent variable. Upon admission, after baseline endoscopic biopsy (by flexible sigmoidoscopy), subjects are placed on a low fat, high fiber diet for 4 wks. Assessment of colonic epithelium, sodium butyrate, and Ki-ras oncogene mutations are performed using endoscopic biopsy, blood, and stool samples. During the funding period 12/01/95 - 11/30/96 a total of 2 subjects have completed the study. Both subjects received a high fiber/low fat diet for 30 days (21.5% fat P/S ratio 1.5, 15.4% protein, 63.2% CHO, 47 g dietary fiber/2400Cal). Both subjects tolerated the study and the procedures involved without event. All subjects have had multiple colonic biopsies taken without difficulty or side effects. There are no definitive scientific results to report at this time. However, several important general conclusions can be made from these studies. First, multiple weekly flexible sigmoidoscopy examinations can be done safely in human volunteers with minimal, if any, adverse effects over 4 weeks. There are no major effects on the microscopic structure of the colonic mucosa after multiple repeated mucosal biopsies. There is early indication based on purely qualitative data on 2 subjects that high fiber in the diet affects the extent of apoptosis in the colon mucosa.