Development of secretin-loaded breath test as a pancreatic exocrine function test : from animal model to human chronic pancreatitis

我们的目的是建立分泌素负荷呼吸试验来评估慢性胰腺炎雄性WBN/Kob大鼠的胰腺外分泌功能。使用Ubit-IR300，我们可以测量放入密封容器的大鼠过期时CO <12> / CO <13>的比值。一开始，我们把有意识的老鼠放进密封的容器里，收集它们的过期时间。我们认为把老鼠放在密封的容器里会造成巨大的压力，包括低氧和高二氧化碳。我们的方法改进如下：1)将混合气体（N_2 80%, O_2 20%）以恒定流量泵入密封容器中，以去除收集空气中预先存在的CO_2。2)监测密封容器空气中O_2和CO_2的浓度，O_2和CO_2分别保持在20%左右和1%以下。3)将排气口置于容器盖上，去除过量的N_2和o_2。2.4)从容器底部收集高浓度的呼气CO_2。我们发现，20和30周龄雄性WBN/Kob大鼠^<12>CO/^<13>CO的比值并不显著低于同龄雄性Wistar大鼠。由于有报道称20周龄和30周龄雄性WBN/Kob大鼠胰腺外分泌功能受损，因此目前的呼吸试验灵敏度较低。同时，我们用血管紧张素转换酶（ACE）抑制剂赖诺普利给10周龄雄性WBN/Kob大鼠饮水处理10周，发现赖诺普利通过抑制转化生长因子-β1 mRNA显著减轻20周龄胰腺炎症和纤维化。因此，我们改变实验方向，在本模型中探讨肾素-血管紧张素系统（RAS）在慢性胰腺炎发病机制中的作用。结果表明，在本模型中，ACE抑制剂莱诺普利和血管紧张素II型受体拮抗剂坎地沙坦均能有效减轻胰腺炎症和纤维化（Gastroenterology 124:1010-1019,2003,J Pharmacol Exp Ther, 308:17-23,2003），表明RAS在慢性胰腺炎发病机制中的重要作用。然而，他们的剂量远远高于临床使用的剂量。因此，我们接下来评估了ACE抑制剂和ARB联合治疗的效果。我们最终发现，在本模型中，无效剂量的ACE抑制剂和ARB联合治疗可以减轻胰腺炎症和纤维化。少

We purposed to develop the secretin-loaded breath test to assess pancreatic exocrine function test using chronic pancreatitis in male WBN/Kob rats. Using Ubit-IR300,we could measure the ratio of ^<12>CO/^<13>CO from the expiration of rats which were put into the sealed container. At the beginning, we put conscious rats into the sealed container to collect their expiration. We thought that keeping rats in the sealed container caused tremendous stress, including hypo O_2 and hyper CO_2. The followings were our methodological modifications:1)Mixed gas (N_2 80%, O_2 20%) is pumped into the sealed container at a constant flow rate to remove pre-existing CO_2 from the collected air.2)Concentrations of O_2 and CO_2 in the air of the sealed container were monitored to keep O_2 and CO_2 around 20% and below 1%, respectively.3)The exhaust was placed on the lid of the container to remove excess N_2 and O_2.4)The expiration CO_2 with high density was collected from the bottom of the container.We r … More ecognized that the ratios of ^<12>CO/^<13>CO were not significantly lower in 20 and 30 weeks old male WBN/Kob rats than the age-matched male Wistar rats. Since it is reported that pancreatic exocrine function is impaired in 20 and 30 weeks old male WBN/Kob rats, the present breath test has low sensitivity.At the same time, we treated 10 weeks old male WBN/Kob rats with lisinopril, angiotensin-converting enzyme (ACE) inhibitor, in drinking water for 10 weeks and found that lisinopril dramatically attenuated pancreatic inflammation and fibrosis at 20 weeks of age by suppressing transforming growth factor-β1 mRNA. Therefore, we shifted the direction of the experiment and newly aimed to explore the roles of renin-angiotensin system (RAS) in the pathogenesis of chronic pancreatitis in the present model. As a result, both lisinopril, ACE inhibitor, and candesartan, angiotensin II type 1 receptor antagonist (ARB) effectively attenuated pancreatic inflammation and fibrosis in the present model (Gastroenterology 124:1010-1019,2003,J Pharmacol Exp Ther J Pharmacol Exp Ther 307:17-23,2003), demonstrating the important roles of RAS in the pathogenesis of chronic pancreatitis. However, their doses were extremely higher than the clinically used doses. Therefore, we next assessed the effect of combined therapy with ACE inhibitor and ARB. We finally found that combined therapy with ineffective doses of ACE inhibitor and ARB attenuated pancreatic inflammation and fibrosis in the present model. Less