Fucoidan ameliorates glucose metabolism by the improvement of intestinal barrier and inflammatory damage in type 2 diabetic rats

Ameliorated Effects of Fucoidan on Dextran Sulfate Sodium-Induced Ulcerative Colitis and Accompanying Anxiety and Depressive Behaviors in Aged C57BL/6 Mice

Fucoidan has shown better effects on the improvement of acute ulcerative colitis (UC). However, the specific mechanisms by which fucoidan improves UC-related behavioral disorders in aged mice, especially its effect on the gut-brain axis, remain to be further explored. C57BL/6 male mice aged 8 months were gavaged with 400 or 100 mg/kg bw day fucoidan for five consecutive weeks, with UC being induced by ad libitum to dextran sulfate sodium (DSS) solution in the fifth week. The results showed that fucoidan ameliorated UC and accompanying anxiety- and depressive-like behaviors with downregulated expressions of (NOD)-like receptor family and pyrin domain-containing 3 (NLRP3), apoptosis-associated speck-like protein (ASC), cysteine aspartate-specific protease-1 (Caspase-1) and interlekin-1β (IL-1β), and elevated mRNA levels of brain-derived neurotrophic factor (Bdnf) and postsynaptic-density protein 95 (Psd-95) in cortex and hippocampus. Furthermore, fucoidan improved the permeability of intestinal barrier and blood-brain barrier and restored the abnormal structure of the gut microbiota with a significantly decreased ratio of Firmicutes to Bacteroidota (F/B) and obviously increased abundance of Akkermansia. As a diet-derived bioactive ingredient, fucoidan might be a better alternative for the prevention of UC and accompanying anxiety- and depressive-like behaviors.

Anti-inflammatory Fucoidan-ConA oral insulin nanosystems for smart blood glucose regulation

The smart oral administration Insulin device has the potential to improve glycemic management. It can reduce the risk of hypoglycemia associated with exogenous Insulin (INS) therapy while also avoiding many of the disadvantages associated with subcutaneous injections. Furthermore, diabetes mellitus (DM) is an endocrine illness characterized by inflammation, and it is critical to minimize the amount of inflammatory markers in diabetic patients while maintaining average blood glucose. In this study, a responsive nanosystem vitamin B12-Fucoidan-Concanavalin A (VB12-FU-ConA NPs) with anti-inflammatory action was developed for smart oral delivery of Insulin. Con A has high sensitivity and strong specificity as a glucose-responsive material. Fucoidan has anti-inflammatory, immunomodulatory, and hypoglycemic functions, and it can bind to Con A to form a reversible complex. Under high glucose conditions, free glucose competitively binds to Con A, which swells the nanocarrier and promotes Insulin release. Furthermore, in the low pH environment of the gastrointestinal tract, positively charged VB12 and anionic fucoidan bind tightly to protect the Insulin wrapped in the carrier, and VB12 can also bind to intestinal epithelial factors to improve transit rate, thereby promoting INS absorption. In vitro tests showed that the release of nanoparticles in hyperglycemic solutions was significantly higher than the drug release in normoglycemic conditions. Oral delivery of the nanosystems dramatically lowered blood glucose levels in type I diabetic mice (T1DM) during in vivo pharmacodynamics, minimizing the risk of hypoglycemia. Blood glucose levels reached a minimum of 8.1 ± 0.4 mmol/L after 8 h. Administering the nanosystem orally notably decreased the serum levels of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) in diabetic mice. The nano delivery system can be degraded and metabolized in the intestinal tract after being taken orally, demonstrating good biodegradability and biosafety. In conclusion, the present study showed that VB12-FU-ConA nanocarriers are expected to be a novel system for rationalizing blood glucose.

Molecular Mechanism of Pasteurized Akkermansia muciniphila in Alleviating Type 2 Diabetes Symptoms

Type 2 diabetes (T2DM) significantly diminishes people's quality of life and imposes a substantial economic burden. This pathological progression is intimately linked with specific gut microbiota, such as Akkermansia muciniphila. Pasteurized A. muciniphila (P-AKK) has been defined as a novel food by the European Food Safety Authority and exhibited significant hypoglycemic activity. However, current research on the hypoglycemic activity of P-AKK is limited to the metabolic level, neglecting systematic exploration at the pathological level. Consequently, its material basis and mechanism of action for hypoglycemia remain unclear. Drawing upon this foundation, we utilized high-temperature killed A. muciniphila (H-K-AKK) with insignificant hypoglycemic activity as the control research object. Assessments were conducted at pathological levels to evaluate the hypoglycemic functions of both P-AKK and H-K-AKK separately. Our study unveiled for the first time that P-AKK ameliorated symptoms of T2DM by enhancing the generation of glucagon-Like Peptide 1 (GLP-1), with pasteurized A. muciniphila total proteins (PP) being a pivotal component responsible for this activity. Utilizing SDS-PAGE, proteomics, and molecular docking techniques, we deeply analyzed the material foundation of PP. We scientifically screened and identified a protein weighing 77.85 kDa, designated as P5. P5 enhanced GLP-1 synthesis and secretion by activating the G protein-coupled receptor (GPCR) signaling pathway, with free fatty acid receptor 2 (FFAR-2) being identified as the pivotal target protein for P5's physiological activity. These findings further promote the widespread application of P-AKK in the food industry, laying a solid theoretical foundation for its utilization as a beneficial food ingredient or functional component.

Joint associations among non-essential heavy metal mixtures and nutritional factors on glucose metabolism indexes in US adults: evidence from the NHANES 2011-2016

Dietary intake can modify the impact of metals on human health, and is also closely related to glucose metabolism in human bodies. However, research on their interaction is limited. We used data based on 1738 adults aged ≥20 years from the National Health and Nutrition Examination Survey 2011-2016. We combined linear regression and restricted cubic splines with Bayesian kernel machine regression (BKMR) to identify metals associated with each glucose metabolism index (P < 0.05 and the posterior inclusion probabilities of BKMR >0.5) in eight non-essential heavy metals (barium, cadmium, antimony, tungsten, uranium, arsenic, lead, and thallium) and glucose metabolism indexes [fasting plasma glucose (FPG), blood hemoglobin A1c (HbA1c) and homeostatic model assessment of insulin resistance (HOMA-IR)]. We identified two pairs of metals associated with glucose metabolism indexes: cadmium and tungsten to HbA1c and barium and thallium to HOMA-IR. Then, the cross-validated kernel ensemble (CVEK) approach was applied to identify the specific nutrient group (nutrients) that interacted with the association. By using the CVEK model, we identified significant interactions between the energy-adjusted diet inflammatory index (E-DII) and cadmium, tungsten and barium (all P < 0.05); macro-nutrients and cadmium, tungsten and barium (all P < 0.05); minerals and cadmium, tungsten, barium and thallium (all P < 0.05); and A vitamins and thallium (P = 0.043). Furthermore, a lower E-DII, a lower intake of carbohydrates and phosphorus, and a higher consumption of magnesium seem to attenuate the positive association between metals and glucose metabolism indexes. Our finding identifying the nutrients that interact with non-essential heavy metals could provide a feasible nutritional guideline for the general population to protect against the adverse effects of non-essential heavy metals on glucose metabolism.

Fructus mori polysaccharide alleviates diabetic symptoms by regulating intestinal microbiota and intestinal barrier against TLR4/NF-κB pathway

Fructus mori polysaccharide (FMP) has a variety of biological activities. In this study, the results showed that FMP alleviated hyperglycemia, insulin resistance, hyperlipidemia, endotoxemia, and high metabolic inflammation levels in type 2 diabetic (T2DM) mice. Next, it was found that the above beneficial effects of FMP on diabetic mice were significantly attenuated after antibiotics eliminated intestinal microbiota (IM) of mice. In addition, FMP suppressed intestinal inflammation and oxidative stress levels by inhibiting the activation of the TLR4/MyD88/NF-κB pathway, and indirectly upregulated the expression of the tight junction proteins Claudin-1, Occludin, and Zonula occlusionn-1 (ZO-1) to repair the intestinal barrier. Interestingly, the protective effect of FMP on the intestinal barrier was also attributed to its regulation of IM. The 16S rRNA and Spearman correlation analysis showed that FMP could repair the intestinal barrier to improve T2DM by remodeling specific IM, especially by significantly inhibiting 93.66 % of endotoxin-producing Shigella and promoting the proliferation of probiotic Allobaculum and Bifidobacterium by 16.31 % and 19.07 %, respectively. This study provided a theoretical support for the application of FMP as a novel probiotic in functional foods for diabetes.

Fucoidan derived from Sargassum pallidum alleviates metabolism disorders associated with improvement of cardiac injury and oxidative stress in diabetic mice

Type 2 diabetes mellitus (T2DM) and its complications have become a serious global health epidemic. Cardiovascular complications have considered as a major cause of high mortality in diabetic patients. Fucoidans from brown algae have diverse medicinal activities, however, few studies reported pharmacological activity of Sargassum. pallidum fucoidan (Sp-Fuc). Therefore, the aim of this study was to investigate the effects of Sp-Fuc on diabetic symptoms and cardiac injury in spontaneous diabetic db/db mice. SP-Fuc at 200 mg/(kg/d) was administered intragastrically to db/db mice for 8 weeks, the effects on hyperlipidemia, hyperglycemia, insulin resistance, and cardiac damage, as well as oxidative stress, inflammation, Nrf2/ARE, and NF-κB signaling pathways, were investigated. Our data demonstrated that Sp-Fuc significantly (p < 0.05) decreased body weights, hyperlipidemia, and hyperglycemia in db/db mice, along with improved insulin sensitivity. Additionally, Sp-Fuc significantly (p < 0.05) alleviated cardiac dysfunction and pathological morphology of cardiac tissue. Sp-Fuc also significantly (p < 0.05) decreased lipid peroxidation, increased antioxidant function, as well as reduced cardiac inflammation, possibly through Nrf2/ARE and NF-κB signaling. Sp-Fuc can ameliorate the metabolism disorders of glucose and lipid in diabetic mice by activating Nrf2/ARE antioxidant signaling, simultaneously reducing cardiac redox imbalance and inflammatory damage. The present findings provide a perspective on the therapy strategy for T2DM and its complications.

The regulatory effects of fucoidan and laminarin on functional dyspepsia mice induced by loperamide

Gastrointestinal dysmotility is a common cause of functional dyspepsia. As two kinds of polysaccharides derived from brown algae, fucoidan and laminarin possess many physiological properties; however, their relative abilities in regulating gastrointestinal motility have not been illustrated yet. In this study, we aimed to investigate the regulatory effect of fucoidan and laminarin on functional dyspepsia mice induced by loperamide. Mice with gastrointestinal dysmotility were treated with fucoidan (100 and 200 mg per kg bw) and laminarin (50 and 100 mg per kg bw). As a result, fucoidan and laminarin reversed the dysfunction mainly through regulating gastrointestinal hormones (motilin and ghrelin), the cholinergic pathway, the total bile acid level, c-kit protein expression, and gastric smooth muscle contraction-related gene expression (ANO1 and RYR3). Moreover, fucoidan and laminarin intervention modulated the gut microbiota profile including the altered richness of Muribaculaceae, Lachnospiraceae, and Streptococcus. The results indicated that fucoidan and laminarin may restore the rhythm of the migrating motor complex and regulate gut microecology. In conclusion, we provided evidence to support that fucoidan and laminarin might have potential abilities to regulate gastrointestinal motility.

Myofibrillar protein-chlorogenic acid complexes ameliorate glucose metabolism via modulating gut microbiota in a type 2 diabetic rat model

Growing evidence suggests that polyphenols could mitigate type 2 diabetes mellitus (T2DM). The glucose-regulatory effects of protein-bound polyphenols, however, have been rarely studied. In this study, macrogenomic and metabolomic analyses were applied to investigate the modulation of myofibrillar protein-chlorogenic acid (MP-CGA) complexes on T2DM rats from the gut microbiota perspective. Results showed that MP-CGA improved hyperglycemia and hyperlipidemia, decreased intestinal inflammation, and reduced intestinal barrier injury. MP-CGA reconstructed gut microbiota in T2DM rats, elevating the abundance of probiotics Bacteroides, Akkermansia, and Parabacteroides while suppressing opportunistic pathogens Enterococcus and Staphylococcus. MP-CGA significantly elevated the concentrations of intestinal metabolites like butyric acid that positively regulate T2DM and reduced the secondary bile acids contents. Therefore, MP-CGA modulated the gut microbiota and related metabolites to maintain stable blood glucose in T2DM rats, providing new insights into the application of protein-polyphenol complexes in foods.

Cordyceps militaris polysaccharide alleviates diabetic symptoms by regulating gut microbiota against TLR4/NF-κB pathway

The relationship between gut microbiota and type 2 diabetes mellitus (T2DM) has attracted increasing attention. In our work, one purified fraction a (AEPSa) was obtained from Cordyceps militaris polysaccharides, and its hypoglycemic activity and underlying mechanisms were investigated in high-fat diet (HFD)- and streptozotocin (STZ)-induced T2DM mice. The results revealed that AEPSa reshaped gut microbiota by increasing Allobaculum, Alistipes, Lachnospiraceae_NK4A136_group and norank_f_Muribaculaceae and decreasing Enterococcus and Ruminococcus_torques_group to inhibit the colonic toll-like receptor 4 (TLR4)/nuclear factor kappa-B (NF-κB) pathway and upregulate intestinal tight junction protein expression, thereby improving glucose and serum lipid metabolism, hormone secretion and complications. Fecal microbiota transplantation (FMT) also confirmed these findings. These results indicated that symptomatic relief of T2DM might be related to AEPSa regulating the gut microbiota against the TLR4/NF-κB pathway to protect the intestinal barrier. Therefore, AEPSa might be developed as a prebiotic agent against T2DM by regulating gut microbiota.

Gut microbiome dysregulation drives bone damage in broiler tibial dyschondroplasia by disrupting glucose homeostasis

Tibial dyschondroplasia (TD) with multiple incentives is a metabolic skeletal disease that occurs in fast-growing broilers. Perturbations in the gut microbiota (GM) have been shown to affect bone homoeostasis, but the mechanisms by which GM modulates bone metabolism in TD broilers remain unknown. Here, using a broiler model of TD, we noted elevated blood glucose (GLU) levels in TD broilers, accompanied by alterations in the pancreatic structure and secretory function and damaged intestinal barrier function. Importantly, faecal microbiota transplantation (FMT) of gut microbes from normal donors rehabilitated the GM and decreased the elevated GLU levels in TD broilers. A high GLU level is a predisposing factor to bone disease, suggesting that GM dysbiosis-mediated hyperglycaemia might be involved in bone regulation. 16S rRNA gene sequencing and short-chain fatty acid analysis revealed that the significantly increased level of the metabolite butyric acid derived from the genera Blautia and Coprococcus regulated GLU levels in TD broilers by binding to GPR109A in the pancreas. Tibial studies showed reduced expression of vascular regulatory factors (including PI3K, AKT and VEFGA) based on transcriptomics analysis and reduced vascular distribution, contributing to nonvascularization of cartilage in the proximal tibial growth plate of TD broilers with elevated GLU levels. Additionally, treatment with the total flavonoids from Rhizoma drynariae further validated the improvement in bone homoeostasis in TD broilers by regulating GLU levels through the regulation of GM to subsequently improve intestinal and pancreatic function. These findings clarify the critical role of GM-mediated changes in GLU levels via the gut-pancreas axis in bone homoeostasis in TD chickens.

Voglibose Regulates the Secretion of GLP-1 Accompanied by Amelioration of Ileal Inflammatory Damage and Endoplasmic Reticulum Stress in Diabetic KKAy Mice

Voglibose is an α-glycosidase inhibitor that improves postprandial hyperglycemia and increases glucagon-like peptide-1 (GLP-1) secretion in patients with type 2 diabetes. Recently, there has been increasing interest in the anti-inflammatory effects of voglibose on the intestine, but the underlying mechanism is not clear. This study evaluated the effects and mechanisms of voglibose on glycemic control and intestinal inflammation. Type 2 diabetic KKAy mice were treated with voglibose (1 mg/kg) by oral gavage once daily. After 8 weeks, glucose metabolism, levels of short-chain fatty acids (SCFAs), systematic inflammatory factors, intestinal integrity and inflammation were evaluated using hematoxylin and eosin staining, immunohistochemistry, immunofluorescence and Western blot analysis. Voglibose ameliorated glucose metabolism by enhancing basal- and glucose-dependent GLP-1 secretion. Several beneficial SCFAs, such as acetic acid and propionic acid, were increased by voglibose in the fecal sample. Additionally, voglibose notably decreased the proportion of pro-inflammatory macrophages and the expression of nuclear factor kappa B but increased the expression of tight junction proteins in the ileum, thus markedly improving intestinal inflammatory damage and reducing the systematic inflammatory factors. Ileal genomics and protein validation suggested that voglibose attenuated inositol-requiring protein 1α-X-box binding protein 1-mediated endoplasmic reticulum stress (ERS). Together, these results showed that voglibose enhanced the secretion of GLP-1, which contributed to the glycemic control in KKAy mice at least in part by regulating intestinal inflammation and the expression of ERS factors.

Mushroom polysaccharides with potential in anti-diabetes: Biological mechanisms, extraction, and future perspectives: A review

Diabetes mellitus (DM) is a global health threat. Searching for anti-diabetic components from natural resources is of intense interest to scientists. Mushroom polysaccharides have received growing attention in anti-diabetes fields due to their advantages in broad resources, structure diversity, and multiple bioactivities, which are considered an unlimited source of healthy active components potentially applied in functional foods and nutraceuticals. In this review, the current knowledge about the roles of oxidative stress in the pathogenesis of DM, the extraction method of mushroom polysaccharides, and their potential biological mechanisms associated with anti-diabetes, including antioxidant, hypolipidemic, anti-inflammatory, and gut microbiota modulatory actions, were summarized based on a variety of in vitro and in vivo studies, with aiming at better understanding the roles of mushroom polysaccharides in the prevention and management of DM and its complications. Finally, future perspectives including bridging the gap between the intervention of mushroom polysaccharides and the modulation of insulin signaling pathway, revealing structure-bioactivity of mushroom polysaccharides, developing synergistic foods, conducting well-controlled clinical trials that may be very helpful in discovering valuable mushroom polysaccharides and better applications of mushroom polysaccharides in diabetic control were proposed.

Perspectives for the Use of Fucoidans in Clinical Oncology

Fucoidans are natural sulfated polysaccharides that have a wide range of biological functions and are regarded as promising antitumor agents. The activity of various fucoidans and their derivatives has been demonstrated in vitro on tumor cells of different histogenesis and in experiments on mice with grafted tumors. However, these experimental models showed low levels of antitumor activity and clinical trials did not prove that this class of compounds could serve as antitumor drugs. Nevertheless, the anti-inflammatory, antiangiogenic, immunostimulating, and anticoagulant properties of fucoidans, as well as their ability to stimulate hematopoiesis during cytostatic-based antitumor therapy, suggest that effective fucoidan-based drugs could be designed for the supportive care and symptomatic therapy of cancer patients. The use of fucoidans in cancer patients after chemotherapy and radiation therapy might promote the rapid improvement of hematopoiesis, while their anti-inflammatory, immunomodulatory, and anticoagulant effects have the potential to improve the quality of life of patients with advanced cancer.

A polysaccharide from Inonotus obliquus ameliorates intestinal barrier dysfunction in mice with type 2 diabetes mellitus

Type 2 diabetes mellitus is a global disease that endangers human health, and the need for the development of nontoxic treatment candidates is urgent. In the present work, one homogeneous polysaccharide from Inonotus obliquus (IN) was isolated, and the protective effect and mechanism of IN on type 2 diabetes mellitus were investigated from the aspects of the intestinal barrier. IN mainly consisted of 9 monosaccharides with a Mw of 373 kDa. IN attenuated body weight loss, alleviated pathological damage, and suppressed the production of proinflammatory cytokines. Additionally, IN repaired the intestinal barrier by upregulating the expression of Ki-67, ZO-1 and MUC2. Furthermore, the abundance of Firmicutes was significantly increased with IN treatment, while the levels of Bacteroidetes were significantly inhibited. In conclusion, IN protected against type 2 diabetes mellitus by ameliorating intestinal barrier dysfunction and might serve as a novel drug candidate for type 2 diabetes mellitus.