Johnson I T
Institute of Food Research, Norwich Research Park, Colney, Norwich NR4 7UA,UK.
Food Chem Toxicol. 2002 Aug;40(8):1171-8. doi: 10.1016/s0278-6915(02)00051-0.
The crypt is the fundamental unit of epithelial proliferation in the intestinal mucosa. The progeny of the pluripotent stem cells located near the base of the crypt migrate towards the crypt orifice, divide once or twice more, and then undergo differentiation, senescence and exfoliation. Programmed cell death (apoptosis) also occurs deep in the proliferative zone. Various lines of evidence suggest that apoptosis provides a protective mechanism against neoplasia by removing genetically damaged stem cells from the epithelium before they can undergo clonal expansion. Several different classes of food constituents, including certain polyunsaturated fatty acids, the short-chain fatty acid butyrate, and some phytochemicals including flavonoids and glucosinolates breakdown products, can modulate both cellular proliferation and programmed death. Each of these food components has also been shown to suppress the emergence of aberrant crypt foci in animal models of carcinogenesis. Further mechanistic and clinical studies are required to establish whether such dietary effects can be exploited to achieve preventive or therapeutic effects in humans.
隐窝是肠黏膜上皮增殖的基本单位。位于隐窝底部附近的多能干细胞的后代向隐窝口迁移，再分裂一到两次，然后经历分化、衰老和脱落。程序性细胞死亡（凋亡）也发生在增殖区深处。各种证据表明，凋亡通过在基因受损的干细胞进行克隆扩增之前将其从上皮中清除，从而提供了一种对抗肿瘤形成的保护机制。几类不同的食物成分，包括某些多不饱和脂肪酸、短链脂肪酸丁酸以及一些植物化学物质（包括黄酮类化合物和硫代葡萄糖苷分解产物），可以调节细胞增殖和程序性死亡。这些食物成分中的每一种在致癌动物模型中也都显示出能抑制异常隐窝病灶的出现。需要进一步的机制研究和临床研究来确定这种饮食效应是否可用于实现对人类的预防或治疗效果。
