Roy C C, Weber A M, Lepage G, Smith L, Levy E
Hôpital Ste-Justine, Department of Pediatrics, Université de Montréal, Canada.
J Pediatr Gastroenterol Nutr. 1988;7 Suppl 1:S1-7. doi: 10.1097/00005176-198811001-00002.
The pancreas has an enormous reserve capacity, and significant malabsorption usually signals complete absence of exocrine function. However, there is evidence that acid lipases of nonpancreatic origin play an important compensatory role. Complete duodenal hydrolysis of fat requires a series of complex interdependent physicochemical events involving pancreatic lipase, colipase, phospholipase A2, and bile salts in an environment where the pH must be close to neutrality. Lipolytic products must then be shuttled through the unstirred water layer to the surface of the microvillus membrane by ionized bile salts, which must be present in sufficient concentrations to form micelles. In pancreatic insufficiency, there is not only a defective lipolytic phase but also an impaired micellar phase. The output of bile salts is decreased because of increased fecal loss. Furthermore, a significant percentage of bile salts precipitate because the duodenum is acidic and there is a large predominance of glycine conjugates. Although much less work has been done on the absorptive phase of patients with pancreatic insufficiency, there is tentative evidence that defective phospholipid absorption, essential fatty acid deficiency, and protein malnutrition could impair the absorptive phase, particularly chylomicron formation. Although significant advances have been made in our understanding of factors responsible for malabsorption associated with pancreatic insufficiency, much remains to be done for the further delineation of defects. It is hoped that this will lead to further refinements of enzyme preparations and to new strategies of intervention.
胰腺具有巨大的储备能力，显著的吸收不良通常表明外分泌功能完全丧失。然而，有证据表明非胰腺来源的酸性脂肪酶发挥着重要的代偿作用。脂肪在十二指肠的完全水解需要一系列复杂的相互依存的物理化学过程，这些过程涉及胰脂肪酶、辅脂酶、磷脂酶A2和胆汁盐，且发生环境的pH值必须接近中性。然后，脂解产物必须通过未搅动的水层，由离子化的胆汁盐转运至微绒毛膜表面，而离子化胆汁盐必须以足够的浓度存在以形成微胶粒。在胰腺功能不全时，不仅脂解阶段存在缺陷，微胶粒阶段也受到损害。由于粪便中胆汁盐流失增加，胆汁盐的分泌量减少。此外，相当一部分胆汁盐会沉淀，因为十二指肠呈酸性，且甘氨酸结合物占主导。虽然关于胰腺功能不全患者吸收阶段的研究较少，但初步证据表明，磷脂吸收缺陷、必需脂肪酸缺乏和蛋白质营养不良可能会损害吸收阶段，尤其是乳糜微粒的形成。尽管我们对胰腺功能不全相关吸收不良的影响因素已有了显著进展，但仍有许多工作有待完成，以进一步明确缺陷所在。希望这将促使酶制剂得到进一步优化，并产生新的干预策略。
