Abnormal ultrastructure of intestinal epithelial barrier in mice with alcoholic steatohepatitis

Resolvin D1 ameliorates hepatic steatosis by remodeling the gut microbiota and restoring the intestinal barrier integrity in DSS-induced chronic colitis

BACKGROUND AND PURPOSE

The maintenance of intestinalmucosalbarrier function plays an important role in hepatic steatosis. Increasing evidence has shown that resolvin D1 (RVD1) exerts a potential effect on hepatic steatosis. The aims of this study were to explore the mechanisms of RVD1 on hepatic steatosis based on the gut-liver axis and intestinal barrier function.

EXPERIMENTAL APPROACH

We established a DSS-induced chronic colitis model to evaluate hepatic steatosis. RVD1 was administered i.p. during the last 4 weeks. The colon and liver samples were stained with hematoxylin and eosin for histopathological analysis. The expression levels of intestinal tight junction genes and inflammatory genes were determined by quantitative PCR. The serum levels of glucose, cholesterol, triglycerides and LPS were measured, and the gut microbiota was analyzed by 16S rRNA gene sequencing.

KEY RESULTS

RVD1 prevented weight loss, histopathological changes, and elevated levels of inflammatory cytokines. Moreover, RVD1 administration attenuated DSS-induced hepatic steatosis and inflammatory responses in mice. In addition, RVD1 improved intestinal barrier function by increasing levels of tight junction molecules and decreasing the plasma LPS levels. The RVD1-treated mice also showed a different gut microbiota composition compared with found in the mice belonging to the DSS group but similar to that in normal chow diet-fed mice.

CONCLUSIONS AND IMPLICATIONS

RVD1 treatment ameliorates DSS-induced hepatic steatosis by ameliorating gut inflammation, improving intestinal barrier function and modulating intestinal dysbiosis.

Buddleoside-Rich Chrysanthemum indicum L. Extract has a Beneficial Effect on Metabolic Hypertensive Rats by Inhibiting the Enteric-Origin LPS/TLR4 Pathway

As the number of patients with metabolic hypertension (MH) is increasing, there is an essential require for global measures to prevent and treat MH. Flavonoids such as buddleoside (BUD) from Chrysanthemum indicum L. are the main pharmacological components of cardiovascular activities. Previous studies have suggested that the buddleoside-rich Chrysanthemum indicum L. extract (BUDE) can reduce blood pressure in spontaneously hypertensive rats (SHR). However, its effect on MH and how it works remains to be researched. In this study, it was observed that BUDE could lower blood pressure, improve dyslipidemia, and decrease the level of plasma LPS in MH rats. Moreover, BUDE improved intestinal flora and increased the expression of occludin and claudin-1 in the colon, and improved the pathological injury of the colon. Western bolt and qRT-PCR experiments showed that BUDE could down-regulate TLR4 and MyD88 protein and mRNA expression and inhibit phosphorylation of IKKβ, IκBα and NF-κB p65 in vessels of MH rats. These results showed that BUDE could regulate intestinal flora, improve intestinal barrier function, reduce the production and penetration of LPS, thereby inhibiting the vascular TLR4/MyD88 pathway, improving vascular endothelial function, and ultimately lowering blood pressure in MH rats. This study provides a new mechanism of BUDE against MH by inhibiting the enteric-origin LPS/TLR4 pathway.

Interactions between Food Hazards and Intestinal Barrier: Impact on Foodborne Diseases

The intestine is an important digestive organ of the human body, and its barrier is the guardian of the body from the external environment. The impairment of the intestinal barrier is believed to be an important determinant in various foodborne diseases. Food hazards can lead to the occurrence of many foodborne diseases represented by inflammation. Therefore, understanding the mechanisms of the impact of the food hazards on intestinal barriers is essential for promoting human health. This review examined the relationship between food hazards and the intestinal barrier in three aspects: apoptosis, imbalance of gut microbiota, and pro-inflammatory cytokines. The mechanism of dysfunctional gut microbiota caused by food hazards was also discussed. This review discusses the interaction among food hazards, intestinal barrier, and foodborne diseases and, thus, offers a new thought to deal with foodborne disease.

Sources and Functions of Extracellular Small RNAs in Human Circulation

Various biotypes of endogenous small RNAs (sRNAs) have been detected in human circulation, including microRNAs, transfer RNAs, ribosomal RNA, and yRNA fragments. These extracellular sRNAs (ex-sRNAs) are packaged and secreted by many different cell types. Ex-sRNAs exhibit differences in abundance in several disease states and have, therefore, been proposed for use as effective biomarkers. Furthermore, exosome-borne ex-sRNAs have been reported to elicit physiological responses in acceptor cells. Exogenous ex-sRNAs derived from diet (most prominently from plants) and microorganisms have also been reported in human blood. Essential issues that remain to be conclusively addressed concern the (a) presence and sources of exogenous ex-sRNAs in human bodily fluids, (b) detection and measurement of ex-sRNAs in human circulation, (c) selectivity of ex-sRNA export and import, (d) sensitivity and specificity of ex-sRNA delivery to cellular targets, and (e) cell-, tissue-, organ-, and organism-wide impacts of ex-sRNA-mediated cell-to-cell communication. We survey the present state of knowledge of most of these issues in this review.