Oral konjac glucomannan for prevention of ionizing radiation-induced injury by regulating gut microbiota and increasing short chain fatty acids

The oral-gut microbiota axis: a link in cardiometabolic diseases

The oral-gut microbiota axis plays a crucial role in cardiometabolic health. This review explores the interactions between these microbiomes through enteric, hematogenous, and immune pathways, resulting in disruptions in microbial balance and metabolic processes. These disruptions contribute to systemic inflammation, metabolic disorders, and endothelial dysfunction, which are closely associated with cardiometabolic diseases. Understanding these interactions provides insights for innovative therapeutic strategies to prevent and manage cardiometabolic diseases.

Immunomodulatory Acidic Polysaccharide from Jujube Fruit (Zizyphus jujuba Mill.): Insight into Their Chemical Characteristics and Modes of Action

Jujube (Zizyphus jujuba Mill.) has been consumed globally as a fruit and a nutraceutical food for millennia. This study presents the isolation and purification of a novel water-soluble polysaccharide fraction, ZJMP-2, from Z. jujuba Mill. ZJMP-2 underwent characterization through Fourier transform infrared (FT-IR), high-performance gel permeation chromatography-laser light scattering (HPGPC-LLS), gas chromatography-mass spectrometry (GC-MS), scanning electron microscopy (SEM), atomic force microscopy (AFM), and nuclear magnetic resonance (NMR) analyses. It consists of glucose, galactose, arabinose, rhamnose, and galacturonic acid in molar ratios of 0.41:0.08:0.11:0.05:0.33 and boasts an average molecular weight of approximately 57.8 kDa. Its backbone features the structure →2)-α-l-Rhap-(1 → 4)-α-d-GalpA-(1 → 4)-α-d-GalpA-6OMe-(1 → 4)-α-d-GalpA-(1 → 3, 4)-α-d-Glcp-(1 →, with branching at →5)-α-l-Araf-(1 →, →4)-β-d-Galp-(1 →, and →4)-α-d-Glcp-(1→ at position O-3 of →3, 4)-α-d-Glcp-(1 →. These structural variations contribute to the pronounced immunoregulatory effects of ZJMP-2. Specifically, ZJMP-2 significantly elevated the expression levels of TLR4, NF-κB, and TRAF6 proteins, enhancing RAW264.7 cell activity, index of splenic lymphocytes, and the production of cytokines and NO, thereby activating macrophages and promoting lymphocyte proliferation. In vivo studies demonstrated that ZJMP-2 promoted the heart, spleen, and bone marrow indices, peripheral blood and spleen cell counts, and the number of heart and bone marrow cells in mice. These findings demonstrated that ZJMP-2 has potential as an immunomodulator and provides valuable insights for developing natural immunomodulators in the pharmaceutical industry.

Radiation protection of sodium alginate and its regulatory effect on intestinal microflora in mice

Prolonged or high-dose exposure to ionizing radiation (IR) can cause damage to normal tissues of the body. Therefore, it is imperative to find effective radiation protective agents to mitigate IR-induced damage. This study evaluated the effects of sodium alginate (SA) on the radiation protection and modulatory effects of gut microorganisms using a 60Coγ-induced damage model in mice. Results showed that SA could reduce the damage of hematopoietic system; and alleviate the oxidative damage in irradiated mice by inhibiting the content of malondialdehyde (MDA) and increasing the activities of superoxide dismutase (SOD) and glutathione (GSH) in serum, spleen, jejunum and liver. Moreover, SA treatment ameliorated IR-induced small intestine lesions and alleviated liver injury. This was consistent with decreased levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), and tumor necrosis factor-α (TNF-α), and increased levels of interferon-γ (IFN-γ) and interleukin-2 (IL-2) after SA treatment. Furthermore, SA treatment reversed IR-induced gut dysbiosis, elevated the Firmicutes/Bacteroidetes ratio, increased the beneficial bacteria and reduced the pathogenic bacteria in the small intestine. In conclusion, the present study demonstrated that SA exerted good radioprotective effect by improving hematopoietic system, alleviating oxidative stress, attenuating liver injury and inflammatory response, and modulating the intestinal microbiota in irradiated mice.

Structural characterization of polysaccharides from Panax ginseng C. A. Meyer root and their triggered potential immunoregulatory and radioprotective activities

With people's increasing awareness of healthy diet, the diverse health-promoting functions of ginseng have been widely recognized. As one of the key functional components, ginseng polysaccharides have attracted increasing research interest. Here, three purified polysaccharide fractions, GPS-1a, GPS-1b, and GPS-2, were obtained from the root extract of Panax ginseng C. A. Meyer. Structurally, GPS-1a and GPS-1b were both linked in a → 6)-α-D-Glcp-(1 → pattern but composed of glucose and galactose in molar ratios of 9.76:0.24 and 9.81:0.19. In contrast, GPS-2 was composed of glucose, galactose, arabinose, rhamnose, and galacturonic acid in a molar ratio of 1.82:1.94:0.79:0.52:4.93. The main backbone consisted of →4)-α-D-GalpA-(1→, →4)-α-D-GalpA-6OMe-(1→, →3, 4)-α-D-GalpA-(1→, →3)-α-L-Rhap-(1 → linages, and its branches are composed of →5)-α-L-Araf-(1→, →4)-β-D-Galp-(1→, →2)-β-D-Glcp-(1→, α-D-GalAp-(1→. Benefitting from this structural variance, GPS-2 exhibited the most significant immunoregulatory and radioprotective efficacies. Specifically, GPS-2 promoted TLR2, NF-κB, and TRAF6 protein expression levels, thereby significantly improving macrophage phagocytosis, splenic lymphocyte proliferation, and stimulation of NO, IL-1β, IL-6, and TNF-α secretion, which activated RAW264.7 and splenic lymphocytes. The following radioprotection activity tests unveiled that GPS-2 increased the organ index, number of peripheral blood cells, cellularity of splenocytes, and bone marrow cell numbers in irradiated mice. This investigation revealed the contribution of polysaccharide structure characteristics to the bioactive expression and elucidated the potential utilization of GPS-2 as a radioprotective agent or immunomodulator.

Colonic long-term retention and colonization of probiotics by double-layer chitosan/tannic acid coating and microsphere embedding for treatment of ulcerative colitis and radiation enteritis

Oral probiotics can alleviate enteric inflammations but their rapid transit through the gut limits their retention and colonization in the colon. Here, a novel strategy integrating the bacterial double-layer coating and hydrogel microsphere embedding techniques was used to highly enhance the colonic retention and colonization efficiency of Lactobacillus rhamnosus GG (LGG). LGG was coated by the double layers of chitosan (CS) and tannic acid (TA), and then embedded in calcium alginate (CA) hydrogel microspheres to form LGG@CT@CA. The microspheres resisted gastric liquids, improving LGG safe transit through the stomach to reach the colon. LGG@CT rapidly released in the colon due to the good swelling of hydrogel microspheres. More importantly, LGG exhibited long-term retention up to 7 days in the colon, and colonized the deep site of the colonic mucosa. LGG@CT@CA had a high therapeutic efficiency of ulcer colitis with the long colon and the low intestinal permeability of colonic tissues. LGG@CT@CA also alleviated the small intestinal damage induced by irradiation and the survival rates were improved. The mechanisms included local ROS decrease, IL-10 increase, and ferroptosis reduction in the small intestine. The oral colon-targeted system holds promise for oral probiotic therapy by the long-term retention and colonization in the colon.

Alginate oligosaccharide improves 5-fluorouracil-induced intestinal mucositis by enhancing intestinal barrier and modulating intestinal levels of butyrate and isovalerate

Chemotherapy-induced mucositis (CIM) is the typical side effect of chemotherapy. This study investigates the potential of alginate oligosaccharide (AOS) in ameliorating CIM induced by 5-fluorouracil (5-FU) in a murine model and its underlying mechanisms. AOS effectively mitigated body weight loss and histopathological damage, modulated inflammatory cytokines and attenuated the oxidative stress. AOS restored intestinal barrier integrity through enhancing expression of tight junction proteins via MLCK signaling pathway. AOS alleviated intestinal mucosal damage by inhibiting TLR4/MyD88/NF-κB signaling pathway, downregulating the pro-apoptotic protein Bax and upregulating the anti-apoptotic protein Bcl-2. Moreover, AOS significantly enriched intestinal Akkermansiaceae and increased the production of short-chain fatty acids (SCFAs), most notably butyrate and isovalerate. Pre-treatment with butyrate and isovalerate also alleviated 5-FU-induced CIM. In conclusion, AOS effectively mitigated CIM through strenghthening intestinal barrier, attenuating inflammation, and modulating gut microbiota and intestianl levels of butyrate and isovalerate. These finding indicate that AOS could be potentially utilized as a supplemental strategy for prevention or mitigation of CIM.

Revitalizing gut health: Liangxue guyuan yishen decoction promotes akkermansia muciniphila -induced intestinal stem cell recovery post-radiation in mice

BACKGROUND

The efficacy of Liangxue Guyuan Yishen Decoction (LGYD), a traditional Chinese medicine, has been scientifically proven in the treatment of radiation-induced intestinal injury (RIII) and preservation of intestinal integrity and function following high-dose radiation exposure. However, further investigation is required to comprehensively elucidate the precise mechanisms underlying the therapeutic effects of LGYD in order to provide potential pharmaceutical options for radiation protection.

PURPOSE

This study aims to elucidate the potential mechanism through which LGYD exerts its therapeutic effects on RIII by modulating the gut microbiota (GM).

METHODS

16 s rRNA analysis was employed to assess the impact of varying doses of whole body irradiation (WBI) on GM in order to establish an appropriate model for this study. The effects of LGYD on GM and SCFA were evaluated using 16 s rRNA and Quantification of SCFA. UHPLC-QE-MS was utilized to identify the active components in LGYD as well as LGYD drug containing serum (LGYD-DS). Subsequently, immunofluorescence and immunohistochemical staining were conducted to validate the influence of LGYD and/or characteristic microbiota on RIII recovery in vivo. The effects of LGYD-DS, characteristic flora, and SCFA on intestinal stem cell (ISC) were assessed by measuring organoid surface area in intestinal organoid model.

RESULTS

The species composition and abundance of GM were significantly influenced by whole-body irradiation with a dose of 8.5 Gy, which was used as in vivo model. LGYD significantly improves the survival rate and promotes recovery from RIII. Additionally, LGYD exhibited a notable increase in the abundance of Akkermansia muciniphila (AKK) and levels of SCFA, particularly isobutyric acid. LGYD-DS consisted of seven main components derived from herbs of LGYD. In vivo experiments indicated that both LGYD and AKK substantially enhanced the survival rate after radiation and facilitated the recovery process for intestinal structure and function. In the organoid model, treatment with LGYD-DS, AKK supernatant or isobutyric acid significantly increased organoid surface area.

CONCLUSIONS

LGYD has the potential to enhance RIII by promoting the restoration of intestinal stem cell, which is closely associated with the upregulation of AKK abundance and production of SCFA, particularly isobutyric acid.

Study on the mechanism of mitigating radiation damage by improving the hematopoietic system and intestinal barrier with Tenebrio molitor peptides

Research on plant and animal peptides has garnered significant attention, but there is a lack of studies on the functional properties of Tenebrio molitor peptides, particularly in relation to their potential mitigating effect on radiation damage and the underlying mechanisms. This study aims to explore the protective effects of Tenebrio molitor peptides against radiation-induced damage. Mice were divided into five groups: normal, radiation model, and low-, medium-, and high-dose Tenebrio molitor peptide (TMP) groups (0.15 g per kg BW, 0.30 g per kg BW, and 0.60 g per kg BW). Various parameters such as blood cell counts, bone marrow DNA content, immune organ indices, serum levels of D-lactic acid, diamine oxidase (DAO), endotoxin (LPS), and inflammatory factors were assessed at 3 and 15 days post gamma irradiation. Additionally, the intestinal tissue morphology was examined through H&E staining, RT-qPCR experiments were conducted to analyze the expression of inflammatory factors in the intestine, and immunohistochemistry was utilized to evaluate the expression of tight junction proteins ZO-1 and Occludin in the intestine. The findings revealed that high-dose TMP significantly enhanced the hematopoietic system function in mice post radiation exposure, leading to increased spleen index, thymus index, blood cell counts, and bone marrow DNA production (p < 0.05). Moreover, TMP improved the intestinal barrier integrity and reduced the intestinal permeability. Mechanistic insights suggested that these peptides may safeguard intestinal barrier function by downregulating the gene expression of inflammatory factors TNF-α, IL-1β, and IL-6, while upregulating the expression of tight junction proteins ZO-1 and Occludin (p < 0.05). Overall, supplementation with TMP mitigates radiation-induced intestinal damage by enhancing the hematopoietic system and the intestinal barrier, offering valuable insights for further investigations into the mechanisms underlying the protective effects of these peptides against ionizing radiation.

An Isofibrous Diet with Fiber Konjac Glucomannan Ameliorates Salmonella typhimurium-Induced Colonic Injury by Regulating TLR2-NF-κB Signaling and Intestinal Microbiota in Mice

This study aimed to investigate the hypothesis that dietary konjac glucomannan (KGM) could alleviate Salmonella typhimurium-induced colitis by modulating intestinal microbiota. Mice were fed an isocaloric and isofibrous diet supplemented with either 7% KGM or cellulose and were treated with 5 × 108 CFU of S. typhimurium. The results showed that KGM had an average molecular weight of 936 kDa and predominantly consisted of mannose and glucose at a molar ratio of 1:1.22. In vivo studies demonstrated that dietary KGM effectively mitigated colonic lesions, oxidative stress, disruption of tight junction protein 2 and occludin, and the inflammatory response induced by S. typhimurium. Moreover, KGM administration alleviated the dramatic upregulation of toll-like receptor 2 (TLR2) and phosphonuclear factor κB (NF-κB) protein abundance, induced by Salmonella treatment. Notably, dietary KGM restored the reduced Muribaculaceae and Lactobacillus abundance and increased the abundance of Blautia and Salmonella in S. typhimurium-infected mice. Spearman correlation analysis revealed that the gut microbiota improved by KGM contribute to inhibit inflammation and oxidative stress. These results demonstrated the protective effects of dietary KGM against colitis by modulating the gut microbiota and the TLR2-NF-κB signaling pathway in response to Salmonella infection.

Advances in the regulation of radiation-induced apoptosis by polysaccharides: A review

Polysaccharides are biomolecules composed of monosaccharides that are widely found in animals, plants and microorganisms and are of interest for their various health benefits. Cumulative studies have shown that the modulation of radiation-induced apoptosis by polysaccharides can be effective in preventing and treating a wide range of radiation injuries with safety and few side effects. Therefore, this paper summarizes the monosaccharide compositions, molecular weights, and structure-activity relationships of natural polysaccharides that regulate radiation-induced apoptosis, and also reviews the molecular mechanisms by which these polysaccharides modulate radiation-induced apoptosis, primarily focusing on promoting cancer cell apoptosis to enhance radiotherapy efficacy, reducing radiation damage to normal tissues, and inhibiting apoptosis in normal cells. Additionally, the role of gut microbiota in mediating the interaction between polysaccharides and radiation is discussed, providing innovative ideas for various radiation injuries, including hematopoiesis, immunity, and organ damage. This review will contribute to a better understanding of the value of natural polysaccharides in the field of radiation and provide guidance for the development of natural radioprotective agents and radiosensitizers.

Oral Curcumin-Thioketal-Inulin Conjugate Micelles against Radiation-Induced Enteritis

Radiation-induced enteritis is an unavoidable complication associated with pelvic tumor radiotherapy, significantly influencing the prognosis of cancer patients. The limited availability of commercial gastrointestinal radioprotectors in clinical settings poses a substantial challenge in preventing radiation enteritis. Despite the inherent radioprotective characteristics of Cur in vitro, its poor solubility in water, instability, and low bioavailability lead to inferior therapeutic effects in vivo. Herein, we developed novel ROS-responsive micelles (CTI) from inulin and curcumin, aimed at mitigating radiation enteritis. CTI micelles had excellent solubility and stability. Importantly, CTI improved the cytotoxicity and bioavailability of curcumin, thereby showing enhanced effectiveness in neutralizing ROS induced by radiation, safeguarding against DNA damage, and reducing radiation-induced cellular mortality. Moreover, in a radiation enteritis mice model, CTI not only alleviated severe radiation-induced intestinal injury but also improved redox-related indicators and reduced inflammatory cytokine expression. Furthermore, CTI effectively increased gut microbiota abundance and maintained gut homeostasis. In conclusion, CTI could be a promising candidate for the clinical management of radiation enteritis. Our study provides a new perspective for radioprotection using natural antioxidants.

Microbiota-derived I3A protects the intestine against radiation injury by activating AhR/IL-10/Wnt signaling and enhancing the abundance of probiotics

The intestine is prone to radiation damage in patients undergoing radiotherapy for pelvic tumors. However, there are currently no effective drugs available for the prevention or treatment of radiation-induced enteropathy (RIE). In this study, we aimed at investigating the impact of indole-3-carboxaldehyde (I3A) derived from the intestinal microbiota on RIE. Intestinal organoids were isolated and cultivated for screening radioprotective tryptophan metabolites. A RIE model was established using 13 Gy whole-abdominal irradiation in male C57BL/6J mice. After oral administration of I3A, its radioprotective ability was assessed through the observation of survival rates, clinical scores, and pathological analysis. Intestinal stem cell survival and changes in the intestinal barrier were observed through immunofluorescence and immunohistochemistry. Subsequently, the radioprotective mechanisms of I3A was investigated through 16S rRNA and transcriptome sequencing, respectively. Finally, human colon cancer cells and organoids were cultured to assess the influence of I3A on tumor radiotherapy. I3A exhibited the most potent radioprotective effect on intestinal organoids. Oral administration of I3A treatment significantly increased the survival rate in irradiated mice, improved clinical and histological scores, mitigated mucosal damage, enhanced the proliferation and differentiation of Lgr5+ intestinal stem cells, and maintained intestinal barrier integrity. Furthermore, I3A enhanced the abundance of probiotics, and activated the AhR/IL-10/Wnt signaling pathway to promote intestinal epithelial proliferation. As a crucial tryptophan metabolite, I3A promotes intestinal epithelial cell proliferation through the AhR/IL-10/Wnt signaling pathway and upregulates the abundance of probiotics to treat RIE. Microbiota-derived I3A demonstrates potential clinical application value for the treatment of RIE.