Novel method for evaluating leaky gut syndrome induced by NSAIDs/PPI and ischemia with health food-derived reagents

抄録

Back ground and aim of present study: Chronic dysfunction of gut mucosal barrier is frequently observed in bad health condition and is called leaky gut syndrome (LGS), which causes leakage of various molecules such as lipopolysaccaride (LPS) from lumen to systemic circulation and likely to cause systemic diseases. Although lactulose/mannitol (L/M) eliminated-ratio into urine is golden standard for diagnosis of LGS in human, detectable molecular size range is narrow (up to MW342). FITC-dextran can detect leakage of bigger molecule (MW4000) and frequently used in animal experiment. However, this reagent cannot be applied to human due to toxicity of FITC. Therefore, we have developed a novel reagent named as "Reagent C" (MW1100-11600) which can evaluate various molecular sizes leaked from gut. Reagent C itself has been consumed as health food and can be applicable both to animals and human. In the present study, we tested usefulness of reagent C using mild and severe gut injury mice model.

Method: Mild gut injury was induced by co-administration of 100 mg/kg of aspirin (p.o) and 10 mg/kg of omeprazole (i.p) twice a day for 6 days. Next day, reagent C or FITC-dextran or lactulose and mannitol was administered orally and plasma or urine concentration of these reagents were measured an hour later. Severe gut injury was induced by inhibiting blood stream of small intestine with vessel clamp for 10 or 20 min followed by reperfusion for 30 min. Reagent C or FITC-dextran was administered orally 30 min prior to clamping and plasma levels of those reagents were measured at immediately after reperfusion finished.

Results: Urine L/M ratio was increased in mild injury model whereas plasma concentration of reagent C (MW1100) and FITC-dextran were comparable to those of control mice. In severe injury model, all sizes of reagent C (MW1100, 3000, 7900, 11600) and FITC-dextran dramatically leaked into peripheral blood.

Conclusion: Reagent C could distinguish mild and severe dysfunction of gut mucosal barrier appropriately without inferiority compared to L/M assay and FITC-dextran, indicating that reagent C is promising molecule for diagnosis of LGS.