Gut Goo: Physiology, Diet, and Therapy of Intestinal Mucus and Biofilms in Gastrointestinal Health and Disease

Review: Human Intestinal Barrier-Optimal Measurement and Effects of Diet in the Absence of Overt Inflammation or Ulceration

BACKGROUND

The intestinal barrier protects humans from potentially deleterious ingested material. It consists of several components: commensal organisms, mucus, and transepithelial pathways, and immune functions.

AIMS

To review, with major focus on human studies, the methods to measure intestinal barrier function in vivo and the impaired intestinal barrier function in non-inflammatory conditions, and the deleterious or beneficial effects of dietary components on the intestinal barrier.

METHODS

PUBMED literature search was intentionally focused, when possible, on human studies conducted in vivo.

RESULTS

Although many gastrointestinal, rheumatological, and degenerative neurological diseases are attributed to impaired intestinal barrier function, often termed "leaky gut," methods of accurate measurement of intestinal barrier function in vivo in humans are still being developed. In vivo measurements provide an overall assessment of barrier function at a whole organ level, whereas ex vivo or in vitro measurements using mucosal biopsies address mechanistic information at the cellular level. Several dietary components are detrimental to the barrier, including ethanol, fat, sugars, gliadin, food additives, emulsifiers, and microbial transglutaminase. Conversely, dietary components improving barrier function include fibre and metabolites such as short-chain fatty acids, anthocyanins, polyphenols, vitamins (such as A and D), zinc, specific amino acids (such as glutamine) and probiotics.

CONCLUSIONS

Currently, data are not exclusively from human studies, and research is needed to corroborate observations in animals or further validate in humans. There are several practical dietary approaches that can be instituted for restoration of the intestinal barrier in humans.

Advanced oral drug delivery systems for gastrointestinal targeted delivery: the design principles and foundations

Oral administration has long been considered the most convenient method of drug delivery, requiring minimal expertise and invasiveness. Unlike injections, it avoids discomfort, wound infections, and complications, leading to higher patient compliance. However, the effectiveness of oral delivery is often hindered by the harsh biological barriers of the gastrointestinal tract, which limit the bioaccessibility and bioavailability of drugs. The development of oral drug delivery systems (ODDSs) represents a critical area for the advancement of pharmacotherapy. This review highlights the characteristics and precise targeting mechanisms of ODDSs. It first examines the unique properties of each gastrointestinal compartment, including the stomach, small intestine, intestinal mucus, intestinal epithelial barrier, and colon. Based on these features, it outlines the targeting strategies and design principles for ODDSs aimed at overcoming gastrointestinal barriers to enhance disease treatment. Lastly, the review discusses the challenges and potential future directions for ODDS development, emphasizing their importance for advancing drug delivery technologies and accelerating their future growth.

Huangqin decoction alleviated irinotecan-induced diarrhea by inhibiting endoplasmic reticulum stress through activating AMPK/mTOR-mediated autophagy

ETHNOPHARMACOLOGICAL RELEVANCE

Huangqin decoction (HQD), a traditional Chinese antidiarrheal formula, is effective in treating chemotherapy-induced diarrhea (CID). However, its underlying mechanism has not been fully clarified.

AIM OF THE STUDY

This study aimed to determine whether the underlying mechanism of HQD against CID is related to the activation of AMPK/mTOR-mediated autophagy inhibiting endoplasmic reticulum (ER) stress.

MATERIALS AND METHODS

Network pharmacology was used to screen potential targets and pathways. The CID mouse model was induced by intraperitoneal injection of 75 mg/kg irinotecan consecutively for four days. The effectiveness of HQD against CID was evaluated through diarrhea score, intestinal epithelial permeability, etc. The histopathological changes of colon were evaluated by HE staining. Alcian blue and immunofluorescence staining were used to assess mucous layer and the expression of MUC2, TJP-1, Occludin, and LC3, relatively. The level of GRP78 and CHOP was assessed by RT-qPCR and WB. Furthermore, the levels of LC3II/I, Beclin-1, P62, AMPK, p-AMPK, mTOR, p-mTOR were evaluated by WB.

RESULTS

Network pharmacology highlighted that the therapeutic effects of HQD against CID may be related to ER stress, autophagy, AMPK, and mTOR signaling pathways, etc. Subsequently, we conducted animal experiments to validate the predicted results. HQD improved CID by attenuating diarrhea, intestinal permeability, etc. HQD could effectively repair intestinal mucous barrier by activating AMPK/mTOR-mediated autophagy to inhibit ER stress.

CONCLUSION

Irinotecan disrupted the intestinal barrier causing diarrhea, while HQD could repair intestinal barrier via inducing AMPK/mTOR-mediated autophagy inhibiting ER stress, thereby exerting therapeutic effects against CID.

Online PGC-LC-MS analysis of colonic mucin O-glycans in ovalbumin-induced food allergy in Balb/c mice by treatment with sea cucumber chondroitin sulfate polysaccharide

The highly sulfated polysaccharide sea cucumber chondroitin sulfate (SCCS) can alleviate intestinal damage and display strong anti-food-allergic activity. The O-glycopattern levels in colonic mucin are closely related to the its protective effect on function of the intestinal barrier. However, the effect of the SCCS on colonic mucin O-glycan has not been investigated. In this study, ovalbumin (OVA)-sensitized allergic mice and SCCS treatment were used. Mouse colonic mucin O-glycome was released and analyzed through reductive β-elimination combined with PGC-LC-MS. A total of presumptive 20 neutral and 28 acidic O-glycan structures were identified, in which the core 2 type acidic O-glycan structure is predominant in Balb/c female mice. Treatment with OVA and SCCS did not change the numbers of colon mucin O-glycan type, but the expression level of total O-glycosylation was more abundant in the SCCS group mice than in the OVA group (1.8-fold), especially for acidic O-glycans (co-modified by fucose and sulfate groups). Furthermore, supplementation with SCCS reversed most of the O-glycan decreasing trend, which may be associated with a return to healthy levels of gut microbiota. In conclusion, our results demonstrate that SCCS could restore colonic mucin O-glycosylation levels and intestinal homeostasis and contribute to enhancing intestinal barrier function.

Targeted and intelligent nano-drug delivery systems for colorectal cancer treatment

Colorectal cancer (CRC) remains a highly heterogeneous malignancy with significant morbidity and mortality worldwide. Despite advancements in surgery, chemotherapy, immunotherapy, and targeted therapy, treatment efficacy is often hampered by drug resistance and systemic toxicity. In recent years, nano-drug delivery systems (NDDS) have emerged as a promising strategy to enhance therapeutic precision, reduce adverse effects, and overcome resistance in CRC treatment. This review discusses the recent advancements in NDDS for CRC treatment, focusing on the optimization of oral drug delivery systems, the development of tumor-specific targeting strategies, and the design of intelligent delivery systems responsive to the tumor microenvironment (TME). Furthermore, we summarize current challenges in NDDS translation and explore future research directions for enhancing their clinical feasibility and therapeutic impact.

Bone Broth Benefits: How Its Nutrients Fortify Gut Barrier in Health and Disease

Bone broth is a traditional nutrient revered by different people from ancient times to the modern era as a remedy for various illnesses. This review investigates the nutritional components of bone broth, focusing primarily on the most abundant amino acids and minerals saturated in bone broth and their impact on health, particularly in the context of intestinal barrier integrity, intestinal permeability, inflammation, and their application in inflammatory bowel disease. Through comprehensive reviews of animal and human studies, this research highlights that bone broth includes amino acids (glutamine, glycine, proline, histidine, arginine), minerals (Ca, P, K, Mg, Zn) that are beneficial and not just a traditional remedy, resolving questions that have been posed for generations. The benefits documented for components in bone broth support the enhancement of gut health, alleviate inflammation in the intestinal barrier, improve intestinal barrier function in health and disease states, particularly in inflammatory bowel disease, as well as enhancing nutrient absorption. Bone broth offers a nutrient-dense option for enhancing overall health and may offer an alternative to dietary supplements with claims for enhanced gut health. We aim to foster interest in and provide evidence to substantiate claims for bone broth as a potential remedy, particularly for maintaining remission in conditions like IBD and possibly functional diarrhea and to encourage further research.

Intestinal Microbiota Dysbiosis Role and Bacterial Translocation as a Factor for Septic Risk

The human immune system is closely linked to microbiota such as a complex symbiotic relationship during the coevolution of vertebrates and microorganisms. The transfer of microorganisms from the mother's microbiota to the newborn begins before birth during gestation and is considered the initial phase of the intestinal microbiota (IM). The gut is an important site where microorganisms can establish colonies. The IM contains polymicrobial communities, which show complex interactions with diet and host immunity. The tendency towards dysbiosis of the intestinal microbiota is influenced by local but also extra-intestinal factors such as inflammatory processes, infections, or a septic state that can aggravate it. Pathogens could trigger an immune response, such as proinflammatory responses. In addition, changes in the host immune system also influence the intestinal community and structure with additional translocation of pathogenic and non-pathogenic bacteria. Finally, local intestinal inflammation has been found to be an important factor in the growth of pathogenic microorganisms, particularly in its role in sepsis. The aim of this article is to be able to detect the current knowledge of the mechanisms that can lead to dysbiosis of the intestinal microbiota and that can cause bacterial translocation with a risk of infection or septic state and vice versa.

Mucoadhesive-to-Mucopenetrating Nanoparticles for Mucosal Drug Delivery: A Mini Review

Mucosal tissue acts as a barrier between the human body's internal environment and the external world. The mucosal tissue is shielded from injurious environmental chemicals, toxins, and pathogens by a mucus layer lining above the mucosal tissue, and meanwhile the periodic mucosal clearance accelerates the removal of mucoadhesive components. And therefore, transmucosal drug delivery is limited. Nanocarriers for mucosal drug delivery is recently developed to enhance either long retention of drugs within the mucus layer or rapid translocation of drugs across the mucus layer. Among all these types of drug delivery systems, mucoadhesive-to-mucopenetrating nanocarriers transport drugs most efficiently into targeted mucosal tissues. In this review, recent progress on the mucoadhesive-to-mucopenetrating drug delivery systems and their application are updated.