Marcinkiewicz M, Grabowska S Z, Czyzewska E
Department of Gastroenterology, J. Sniadecki's District Hospital, Bialystok, Poland.
Curr Med Res Opin. 1998;14(3):145-53. doi: 10.1185/03007999809113354.
Oesophageal mucosa has well established protective mechanisms, which operate within pre-epithelial, epithelial and post-epithelial compartments. Since refluxed acid and pepsin always act from the luminal side of the mucosa, protective factors like EGF, operating as a part of pre-epithelial defence, are thought to be pivotal in the maintenance of the integrity of the oesophageal mucosa. The significant contribution of salivary EGF to the quality of the oesophageal mucosal barrier has been demonstrated in an experimental setting and in a clinical scenario. Patients with low salivary EGF levels are predisposed to severe oesophageal damage if they develop gastro-oesophageal reflux and are a high-risk group for development of Barrett's oesophagus. Not only the salivary glands but also the human oesophagus has a profound ability to elaborate and release EGF. Some changes in luminal release of EGF during oesophageal mucosal exposure to intraluminal damaging factors imply its role in the oesophageal protective mechanisms. To exert biological effects within the oesophageal mucosal compartment, EGF requires binding to the ligand-binding domain of its receptor. This process results in receptor dimerisation, autophosphorylation and activation of intracellular signal transduction pathways. EGF receptors are localised on the basolateral and luminal aspect of the mucosal cells playing an important role in fast regeneration of oesophageal epithelium through the high mitotic activity of its proliferative zone. An increase in the rate of salivary EGF secretion during masticatory stimulation suggests its potential therapeutic benefit in the treatment of patients with damaged oesophageal mucosa.
食管黏膜具有完善的保护机制，这些机制在上皮前、上皮和上皮后区室发挥作用。由于反流的酸和胃蛋白酶总是从黏膜腔侧起作用，像表皮生长因子（EGF）这样作为上皮前防御一部分发挥作用的保护因子被认为在维持食管黏膜完整性方面起着关键作用。唾液表皮生长因子对食管黏膜屏障质量的重要贡献已在实验环境和临床场景中得到证实。唾液表皮生长因子水平低的患者如果发生胃食管反流，易发生严重的食管损伤，并且是发生巴雷特食管的高危人群。不仅唾液腺，而且人类食管也具有合成和释放表皮生长因子的强大能力。食管黏膜暴露于腔内损伤因素期间表皮生长因子腔内释放的一些变化暗示了其在食管保护机制中的作用。为了在食管黏膜区室发挥生物学效应，表皮生长因子需要与其受体的配体结合域结合。这个过程导致受体二聚化、自身磷酸化以及细胞内信号转导通路的激活。表皮生长因子受体定位于黏膜细胞的基底外侧和腔面，通过其增殖区的高有丝分裂活性在食管上皮的快速再生中发挥重要作用。咀嚼刺激期间唾液表皮生长因子分泌速率的增加表明其在治疗食管黏膜受损患者方面具有潜在的治疗益处。
