N-ACETYLCYSTEINE IMPROVES INTESTINAL BARRIER IN PARTIALLY HEPATECTOMIZED RATS

Polyphenol-Rich Liupao Tea Extract Prevents High-Fat Diet-Induced MAFLD by Modulating the Gut Microbiota

The modulation of gut microbiota dysbiosis might regulate the progression of metabolic-associated fatty liver disease (MAFLD). Here, we found that polyphenol-rich Liupao tea extract (PLE) prevents high-fat diet (HFD)-induced MAFLD in ApoE^-/- male mice accompanied by protection of the intestinal barrier and downregulation of lipopolysaccharide (LPS)-related Toll-like receptor 4 (TLR4)-myeloid differentiation primary response 88 (MyD88) signaling in the liver. Fecal microbiome transplantation (FMT) from PLE-and-HFD-treated mice delayed MAFLD development significantly compared with FMT from HFD-treated mice. In this case, 16S rRNA gene sequencing revealed that Rikenellaceae and Odoribacter were significantly enriched and that Helicobacter was significantly decreased in not only the HFD+PLE group but also the HFD+PLE-FMT group. Furthermore, the level of 3-sulfodeoxycholic acid was significantly decreased in the HFD+PLE-FMT group compared with the HFD-FMT group. In conclusion, our data demonstrate that PLE could modulate the MAFLD phenotype in mice and that this effect is partly mediated through modulation of the gut microbiota.

Perspective: Prospects for Nutraceutical Support of Intestinal Barrier Function

Impairment of intestinal barrier function is linked to certain pathologies and to aging, and can be a cause of bacterial infections, systemic and hepatic inflammation, food allergies, and autoimmune disorders. The formation and maintenance of intestinal tight junctions is supported by glucagon-like peptide-2 (GLP-2), which via insulin-like growth factor I activity boosts phosphoinositide 3-kinase/Akt/mammalian target of rapamycin complex 1 (PI3K/Akt/mTORC1) signaling in enterocytes. 5'-AMP-activated protein kinase (AMPK) activity as well as estrogen receptor-β (ERβ) activity are also protective in this regard. Conversely, activation of mitogen-activated protein kinases (MAPKs) and cellular Src (c-Src) under inflammatory conditions can induce dissociation of tight junctions. Hence, nutraceuticals that promote GLP-2 secretion from L cells-effective pre/probiotics, glycine, and glutamine-as well as diets rich in soluble fiber or resistant starch, can support intestinal barrier function. AMPK activators-notably berberine and the butyric acid produced by health-promoting microflora-are also beneficial in this regard, as are soy isoflavones, which function as selective agonists for ERβ. The adverse impact of MAPK and c-Src overactivation on the intestinal barrier can be combatted with various antioxidant measures, including phycocyanobilin, phase 2-inducer nutraceuticals, and N-acetylcysteine. These considerations suggest that rationally designed functional foods or complex supplementation programs could have clinical potential for supporting and restoring healthful intestinal barrier function.

Gut dysbiosis, leaky gut, and intestinal epithelial proliferation in neurological disorders: towards the development of a new therapeutic using amino acids, prebiotics, probiotics, and postbiotics

Here we offer a review of the evidence for a hypothesis that a combination of ingestible probiotics, prebiotics, postbiotics, and amino acids will help ameliorate dysbiosis and degeneration of the gut, and therefore promote restoration of nervous system function in a number of neurological indications.

N-acetylcysteine may prevent severe intestinal damage in necrotizing enterocolitis

OBJECTIVE

The aim of this study was to evaluate the preventive effect of N-acetylcysteine (NAC) on the development of necrotizing enterocolitis (NEC) in an experimental rat model.

MATERIAL AND METHODS

Thirty newborn Sprague-Dawley rats were randomly divided into 3 groups: NEC, NEC + NAC, and control. Necrotizing enterocolitis was induced by enteral formula feeding, exposure to hypoxia-hyperoxia, and cold stress. Pups in the NEC + NAC group were administered NAC at a dose of 150 mg/kg daily by intraperitoneal route from the first day until the last day of the study. All pups were killed on the fifth day. Proximal colon and ileum were excised for histopathologic, immunohistochemical (terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin nick end-labeling and caspase-3, caspase-8, caspase-9), and biochemical evaluation, including xanthine oxidase, total antioxidant status, total oxidant status, malondialdehyde, and myeloperoxidase activities.

RESULTS

The pups in the NEC + NAC group had better clinical sickness scores compared with those in the NEC group (P < .05). In histopathologic and apoptosis evaluations (terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin nick end-labeling and immunohistochemical evaluation for caspase-3 and caspase-9), the severity of bowel damage was significantly less in the NEC + NAC group compared with the NEC group (P < .01). Tissue malondialdehyde, myeloperoxidase, xanthine oxidase levels, and total oxidant status were significantly decreased in the NEC + NAC group, whereas total antioxidant status (TAS) was significantly increased in the NEC + NAC group (P < .01).

CONCLUSION

N-acetylcysteine therapy significantly reduced the severity of intestinal damage in NEC.

Experimental and clinical evidence for modification of hepatic ischaemia-reperfusion injury by N-acetylcysteine during major liver surgery

BACKGROUND

Hepatic ischaemia-reperfusion (I/R) injury occurs in both liver resectional surgery and in transplantation. The biochemistry of I/R injury involves short-lived oxygen free radicals. N-acetylcysteine (NAC) is a thiol-containing synthetic compound used in the treatment of acetaminophen toxicity. The present study is a detailed overview of the experimental and clinical evidence for the use of NAC as a pharmaco-protection agent in patients undergoing major liver surgery or transplantation.

METHODS

A computerized search of the Medline, Embase and SCI databases for the period from 1st January 1988 to 31st December 2008 produced 40 reports. For clinical studies, the quality of reports was assessed according to the criteria reported by the Cochrane communication review group.

RESULTS

Nineteen studies evaluated NAC in experimental liver I/R injury. NAC was administered before induction of ischaemia in 13. The most widely used concentration was 150 mg/kg by intravenous bolus. Fifteen studies report an improvement in outcome, predominantly a reduction in transaminase. Seven studies used an isolated perfused liver model with all showing improvement (predominantly an improvement in bile production after N-acetylcysteine). Two out of four transplantation models showed an improvement in hepatic function. Clinical studies in transplantation show a modest improvement in transaminase levels with no beneficial effect on either patient or graft survival.

CONCLUSION

N-acetylcysteine, given before induction of a liver I/R injury in an experimental model can ameliorate liver injury. Clinical outcome data are limited and there is currently little evidence to justify use either in liver transplantation or in liver resectional surgery.

N-Acetylcysteine improves disturbed ileal contractility following partial hepatectomy in rats

BACKGROUND AND AIMS

It is well known that disturbed intestinal motility and bacterial overgrowth may occur following partial hepatectomy. These events have been followed by the translocation of enteric bacteria that play a major role in the development of infections. We designed the present study to evaluate the effect of N-acetylcysteine (NAC) on ileal muscle contractility as an indication of intestinal motility.

METHODS

Sprague-Dawley rats were divided into four groups (n = 6): sham, sham plus preoperative intraperitoneal NAC injection, hepatectomy, and hepatectomy plus preoperative intraperitoneal NAC injection. Contractile and relaxant responses in isolated ileal smooth muscle strips were determined using an in vitro muscle technique. Statistical analyses were performed by Kruskal-Wallis and Mann-Whitney U-tests.

RESULTS

Contractile responses to KCl and carbachol were significantly decreased in the ileal strips of the hepatectomy group when compared to the sham-operated control group. The impaired contraction of strips was markedly improved by preoperative NAC treatment. However, neither the electrical field stimulation nor the sodium nitroprusside-mediated relaxant responses changed in any of the groups.

CONCLUSIONS

Our data indicated that disturbed ileal contractility after partial hepatectomy was remedied by preoperative NAC treatment, which in turn might cause attenuation of bacterial translocation.