Effect of alpha-naphthylisothiocyanate-induced liver injury on intestinal adaptation in a rat model of short bowel syndrome

Modulating intestinal barrier function by sphingosine-1-phosphate receptor 1 specific agonist SEW2871 attenuated ANIT-induced cholestatic hepatitis via the gut-liver axis

Bile acid (BA) homeostasis throughout the enterohepatic circulation system is a guarantee of liver physiological functions. BA circulation disorders is one of the characteristic clinical manifestations of cholestasis, and have a closely relationship with intestinal barrier function, especially ileum. Here, our in vivo and in vitro studies showed that intestinal tight junctions (TJs) were disrupted by α-naphthylisothiocyanate (ANIT), which also down-regulated the protein expression of sphingosine-1-phosphate receptor 1 (S1PR1) in the top of villus of mice ileum. Activating S1PR1 by specific agonist SEW2871 could improve TJs via inhibiting ERK1/2/LKB1/AMPK signaling pathway in the ileum of ANIT-treated mice and ANIT-cultured Caco-2 cells. SEW2871 not only regained ileum TJs by activating S1PR1 in the epithelial cells of ileum mucosa, but also recovered ileum barrier function, which was further verified by the recovered BA homeostasis in mice ileum (content and tissue) by using of high-performance liquid chromatographytandem mass spectrometry (LC-MS/MS). Subsequently, the improved intestinal injury and inflammation further strengthened that SEW2871 modulated intestinal barrier function in ANIT-treated mice. Finally, our data revealed that along with the down-regulated levels of serum lipopolysaccharides (LPS), SEW2871 improved liver function and relieved hepatitis via blocking TLR4/MyD88/NF-kB signaling pathway in ANIT-treated mice. In conclusion, these results demonstrated that activating intestinal S1PR1 by SEW2871 could modulate intestinal barrier function, leading to the improvement of cholestatic hepatitis in ANIT-treated mice via the "gut-liver" axis.

The effect of hepatocyte growth factor on intestinal adaption in an experimental model of short bowel syndrome

PURPOSE

Nowadays, the standard therapy for patients with short bowel syndrome is parenteral nutrition (PN). Various growth factors have been tested to achieve weaning from prolonged PN administration. We evaluated the effect of hepatocyte growth factor (HGF) on structural intestinal adaptation and cell proliferation in a rat model of SBS.

METHODS

Thirty Sprague-Dawley rats were divided into three groups; group A rats (sham) underwent bowel transection, group B rats underwent a 75% bowel resection, and group C rats underwent the same procedure but were treated postoperatively with HGF. Histopathologic parameters of intestinal adaptation were determined, while microarray and rt-PCR analyses of ileal RNA were also performed.

RESULTS

Treatment with HGF resulted in significant increase in body weight, while the jejunal and ileal villus height and crypt depth were increased in HGF rats (36%, p < 0.05 and 27%, p < 0.05 respectively). Enterocyte proliferation was also significantly increased in HGF rats (21% p < 0.05). Microarray and quantitative rt-PCR analyses showed that the genes hgfac, rac 1, cdc42, and akt 1 were more than twofold up-regulated after HGF treatment.

CONCLUSION

HGF emerges as a growth factor that enhances intestinal adaptation. The future use of HGF may potentially reduce the requirement for PN in SBS patients.

Intrahepatic cholestasis induced by α-naphthylisothiocyanate can cause gut-liver axis disorders

Clinical studies have shown that Intrahepatic cholestasis is closely related to intestinal injury. The gut-liver axis theory suggests that the intestine and liver are closely related, and that bile acids are important mediators linking the intestine and liver. We compared two cholestasis models: a single injection model that received a single subcutaneous ANIT injection (75 mg/kg), and a multiple subcutaneous injection model that received an injection of ANIT (50 mg/kg) every other day for 2 weeks. We used Transmetil (ademetionine 1,4-butanedisulfonate) to relieve intrahepatic cholestasis in the multiple injection group. In the multiple injection group, we found increased hepatic bile duct hyperplasia, increased fibrosis of the liver, increased small intestine inflammation and oxidative damage, increased harmful bile acids, decreased bile acids transporter levels. After treatment with Transmetil, the liver and gut injuries were relieved. These results suggest that intrahepatic cholestasis can cause disorders of the gut-liver axis.