Rhamnan sulphate from green algae Monostroma nitidum improves constipation with gut microbiome alteration in double-blind placebo-controlled trial

Oral Administration of Rhamnan Sulfate from Monostroma nitidum Suppresses Atherosclerosis in ApoE-Deficient Mice Fed a High-Fat Diet

Oral administration of rhamnan sulfate (RS), derived from the seaweed Monostroma nitidum, markedly suppresses inflammatory damage in the vascular endothelium and organs of lipopolysaccharide-treated mice. This study aimed to analyze whether orally administered RS inhibits the development of atherosclerosis, a chronic inflammation of the arteries. ApoE-deficient female mice were fed a normal or high-fat diet (HFD) with or without RS for 12 weeks. Immunohistochemical and mRNA analyses of atherosclerosis-related genes were performed. The effect of RS on the migration of RAW264.7 cells was also examined in vitro. RS administration suppressed the increase in blood total cholesterol and triglyceride levels. In the aorta of HFD-fed mice, RS reduced vascular smooth muscle cell proliferation, macrophage accumulation, and elevation of VCAM-1 and inhibited the reduction of Robo4. Increased mRNA levels of Vcam1, Mmp9, and Srebp1 in atherosclerotic areas of HFD-fed mice were also suppressed with RS. Moreover, RS directly inhibited the migration of RAW264.7 cells in vitro. Thus, in HFD-fed ApoE-deficient mice, oral administration of RS ameliorated abnormal lipid metabolism and reduced vascular endothelial inflammation and hyperpermeability, macrophage infiltration and accumulation, and smooth muscle cell proliferation in the arteries leading to atherosclerosis. These results suggest that RS is an effective functional food for the prevention of atherosclerosis.

How vitamins act as novel agents for ameliorating diabetic peripheral neuropathy: A comprehensive overview

Diabetic peripheral neuropathy (DPN) is a pervasive and incapacitating sequela of diabetes, affecting a significant proportion of those diagnosed with the disease, yet an effective treatment remains elusive. Vitamins have been extensively studied, emerging as a promising target for diagnosing and treating various systemic diseases, but their role in DPN is not known. This review collates and synthesizes knowledge regarding the interplay between vitamins and DPN, drawing on bibliographies from prior studies and relevant articles, and stratifying the therapeutic strategies from prophylactic to interventional. In addition, the clinical evidence supporting the use of vitamins to ameliorate DPN is also evaluated, underscoring the potential of vitamins as putative therapeutic agents. We anticipate that this review will offer novel insights for developing and applying vitamin-based therapies for DPN.

The utility of algae as sources of high value nutritional ingredients, particularly for alternative/complementary proteins to improve human health

As the global population continues to grow, the demand for dietary protein is rapidly increasing, necessitating the exploration of sustainable and nutritious protein sources. Algae has emerged as a promising food source due to their high value ingredients such as proteins, as well as for their environmental sustainability and abundance. However, knowledge gaps surrounding dietary recommendations and food applications restrict algae's utilization as a viable protein source. This review aims to address these gaps by assessing the suitability of both microalgae and macroalgae as alternative/complementary protein sources and exploring their potential applications in food products. The first section examines the potential suitability of algae as a major food source by analyzing the composition and bioavailability of key components in algal biomass, including proteins, lipids, dietary fiber, and micronutrients. Secondly, the biological effects of algae, particularly their impact on metabolic health are investigated with an emphasis on available clinical evidence. While evidence reveals protective effects of algae on glucose and lipid homeostasis as well as anti-inflammatory properties, further research is required to understand the longer-term impact of consuming algal protein, protein isolates, and concentrates on metabolic health, including protein metabolism. The review then explores the potential of algal proteins in food applications, including ways to overcome their sensory limitations, such as their dark pigmentation, taste, and odor, in order to improve consumer acceptance. To maximize algae's potential as a valuable protein source in the food sector, future research should prioritize the production of more acceptable algal biomass and explore new advances in food sciences and technology for improved consumer acceptance. Overall, this paper supports the potential utility of algae as a sustainable and healthy ingredient source for widespread use in future food production.

LimosiLactobacillus pentosus Isolated from Mustard Relieves Drug-induced Constipation in Mice Fed a High-fat Diet by Modulating Enteric Neurotransmitter Function

Functional constipation is one of the most common gastrointestinal disorders. Oxidative stress can aggravate organ dysfunction. Enteric neurotransmitters have significant effects on the regulation of the enteric nervous system and intestinal muscle contraction. Oxidative stress and reduced gastrointestinal motility are considered to be one of the main causes of constipation. This study aimed to investigate whether LimosiLactobacillus pentosus CQZC02 alleviated loperamide hydrochloride (Lop)-induced constipation in mice under high-fat diet (HFD) conditions and to elucidate the underlying mechanism, focusing on enteric neurotransmitters. Four-week-old female BALB/c mice were randomly divided into five groups: normal group (Nor), constipation model group (H-Lop), L. pentosus CQZC02 low-dose group (H-Lop + ZC02L), L. pentosus CQZC02 high-dose group (H-Lop + ZC02H), and LimosiLactobacillus bulgaricus control group (H-Lop + LB). The fecal weight, water content, and total gastrointestinal transit time were measured to determine whether the mice were constipated. Small bowel and colon tissue damage was assessed by hematoxylin and eosin staining, while the degree of damage was determined by double-blind scoring. The levels of serum oxidative stress markers malondialdehyde, superoxide dismutase, glutathione peroxidase, and catalase and neurotransmitters motilin, gastrin, substance P, endothelin, somatostatin, and vasoactive intestinal peptide were measured. The gene expression levels of endothelial nitric oxide synthase, inducible nitric oxide synthase, neuronal nitric oxide synthase, nuclear factor kappa-B, and cyclooxygenase-2 in small intestine tissue were calculated. The constipation symptoms of mice in H-Lop group were manifested by a variety of physiological indicators. In addition, compared with the H-Lop group, H-Lop + ZC02H could effectively relieve the symptoms of constipation in mice. In symptom characterization, the mice in the H-Lop + ZC02H group lost weight and increased feces and water content. In functional experiments, gastrointestinal motility was enhanced; the inflammation score of intestinal tissue was decreased, and gene expression levels were modulated; serum oxidative factor levels were modulated, and oxidative stress levels were decreased.

Preparation, structures, and biological functions of rhamnan sulfate from green seaweed of the genus Monostroma: A review

Rhamnan sulfate, a rhamnose-rich sulfated polysaccharide, is present in the cell walls of green seaweed belonging to the genus Monostroma. This macromolecule demonstrates promising therapeutic properties, including anti-coagulant, thrombolytic, anti-viral, anti-obesity, and anti-inflammatory activities, which hold potential applications in food and medical industries. However, rhamnan sulfate has not garnered as much attention from researchers as other seaweed polysaccharides, including alginate, carrageenan, and fucoidan. This review discusses the extraction and purification techniques of rhamnan sulfate, delves into its chemical structures and related elucidation approaches, and provides an overview of its biological functions. Future research should focus on the structure-activity relationship of rhamnan sulfate and the industrial preparation of rhamnan sulfate with a specific homogeneous structure to facilitate its practical applications.

Fermented Bamboo Fiber Improves Productive Performance by Regulating Gut Microbiota and Inhibiting Chronic Inflammation of Sows and Piglets during Late Gestation and Lactation

Sows exhibit metabolic syndrome and significant changes in intestinal microbiota during late gestation and lactation, affecting sow performance and piglet health. Dietary fiber (DF) is widely applied to improve sow performance by modulating gut microbiota and their by-products. Here, 60 sows were randomly allocated to groups, including CON (8% wheat bran), FBF-1 (1% fermented bamboo fiber), FBF-2 (2.5% fermented bamboo fiber), and FBF-3 (4% fermented bamboo fiber) from day 80 of gestation (G80d) to the end of lactation (L21d). Compared with CON, the FBF-3 diet decreased lactation backfat loss, increased average daily feed intake (ADFI) during lactation, and the weight gain of piglets, while supplementation of FBF increased fecal water content and reduced the rate of constipation in sows. Further, the yield and quality of milk of sows in FBF groups were improved. The FBF-3 diet significantly reduced markers of intestinal permeability (diamine oxidase and endotoxin) and systemic inflammation (interleukin-6 [IL-6] and tumor necrosis factor alpha) in sow serum during lactation, while it increased the anti-inflammatory marker (IL-10). Similarly, the piglets in the FBF-2 and FBF-3 groups had lower levels of IL-6 and higher levels of IgG, IgM, and insulin-like growth factor in serum. In addition, sows fed the 4% FBF diet had higher levels of acetate, propionate, butyrate, and total short-chain fatty acids (SCFAs) in feces than CON, and total SCFAs were promoted in piglets from the FBF-3 group. Spearman correlation analysis showed that immunity, inflammation, and intestinal microbiota are closely related to sow performance, which can affect piglet growth. The potential mechanism could be that FBF promoted the enrichment of beneficial genera such as Lachnospira, Lachnospiracea_XPB1014_Group, and Roseburia and the production of SCFAs in the sow's intestine, and reduced the relative abundance of harmful bacteria such as Fusobacterium, Sutterellaceae, and Sutterella. Meanwhile, the intake of FBF by sows affected the gut microbial composition of their offspring piglets, significantly increasing the relative abundance of beneficial bacteria Alistipes and Lachnoclostridium and decreasing the relative abundance of pathogenic bacteria Trueperella among colonic microorganisms. IMPORTANCE Dietary fiber is widely applied in the nutrition of sows due to its potential value in improving performance and intestinal health. Fermented bamboo fiber, rich in dietary fiber, has not been fully evaluated to be used in sow diets. Sows mobilize body reserves during gestation and lactation due to nutrients being prioritized for lactation purposes while feeding piglets, which generally leads to metabolism and immunity undergoing drastic changes. The main manifestations are increased inflammation and intestinal permeability and disturbed intestinal flora, which ultimately reduces the ADFI and milk quality, thus affecting the growth of piglets. The study described here is the first attempt to provide FBF for sows in late gestation and lactation can reverse this process. The 4% FBF was initially explored to have the most significantly beneficial effect. It provides a potentially effective method for dietary modification to control the gut microbiota and its metabolites to improve sow and piglet health. Moreover, the sow-piglet model offers a reference for investigating the impact of dietary fiber on the intestinal health of human mothers and infants.

Beneficial effects of seaweed-derived components on metabolic syndrome via gut microbiota modulation

Metabolic syndrome comprises a group of conditions that collectively increase the risk of abdominal obesity, diabetes, atherosclerosis, cardiovascular diseases, and cancer. Gut microbiota is involved in the pathogenesis of metabolic syndrome, and microbial diversity and function are strongly affected by diet. In recent years, epidemiological evidence has shown that the dietary intake of seaweed can prevent metabolic syndrome via gut microbiota modulation. In this review, we summarize the current in vivo studies that have reported the prevention and treatment of metabolic syndrome via seaweed-derived components by regulating the gut microbiota and the production of short-chain fatty acids. Among the surveyed related articles, animal studies revealed that these bioactive components mainly modulate the gut microbiota by reversing the Firmicutes/Bacteroidetes ratio, increasing the relative abundance of beneficial bacteria, such as Bacteroides, Akkermansia, Lactobacillus, or decreasing the abundance of harmful bacteria, such as Lachnospiraceae, Desulfovibrio, Lachnoclostridium. The regulated microbiota is thought to affect host health by improving gut barrier functions, reducing LPS-induced inflammation or oxidative stress, and increasing bile acid production. Furthermore, these compounds increase the production of short-chain fatty acids and influence glucose and lipid metabolism. Thus, the interaction between the gut microbiota and seaweed-derived bioactive components plays a critical regulatory role in human health, and these compounds have the potential to be used for drug development. However, further animal studies and human clinical trials are required to confirm the functional roles and mechanisms of these components in balancing the gut microbiota and managing host health.

Similarities and differences in constipation phenotypes between Lep knockout mice and high fat diet-induced obesity mice

CRISPR-Cas9-mediated leptin (Lep) knockout (KO) mice exhibited prominent phenotypes for constipation, even though they were not compared with other model animals. This study compared the stool excretion, gastrointestinal motility, histological structure, mucin secretion, and enteric nerve function in Lep KO and high fat diet (HFD)-treated mice to determine if there were differences in their phenotypes for constipation. Most obesity phenotypes, including fat weight, adipocyte size, expression of lipolytic proteins (HSL, perilipin, and ATGL), and glucose concentrations, were detected similarly in the Lep KO and HFD-treated mice. They showed a similar decrease in the excretion parameters, including the stool number, weight, and water content, while the same pattern was detected in the gastrointestinal motility and intestinal length. A similar decrease in the mucosal layer thickness, muscle thickness, ability for mucin secretion, and expression of water channel (aquaporin 3 and 8) genes was detected in the mid-colon of the Lep KO and HFD-treated mice, but the alteration rate in some levels was greater in the HFD-treated group than the Lep KO mice. On the other hand, the levels of c-kit, nNOS, NSE, and PGP9.5 expression for the enteric neurons and intestitial cells of Cajal (ICC) were remarkably lower in the mid-colon of the HFD-treated mice than in the Lep KO mice, but the level of most proteins in both groups remained lower than those in the control group. A similar alteration pattern in the expression of muscarinic acetylcholine receptors (mAChRs) and serotonin receptors was detected in the Lep KO and HFD-treated mice. These results suggest that most phenotypes for obesity-induced constipation were similarly detected in the Lep KO and HFD-treated mice, but there was a difference in the regulatory function of the enteric nervous system (ENS).

Dietary Polysaccharides as Modulators of the Gut Microbiota Ecosystem: An Update on Their Impact on Health

A polysaccharide is a macromolecule composed of more than ten monosaccharides with a wide distribution and high structural diversity and complexity in nature. Certain polysaccharides are immunomodulators and play key roles in the regulation of immune responses during the progression of some diseases. In addition to stimulating the growth of certain intestinal bacteria, polysaccharides may also promote health benefits by modulating the gut microbiota. In the last years, studies about the triad gut microbiota–polysaccharides–health have increased exponentially. In consequence, in the present review, we aim to summarize recent knowledge about the function of dietary polysaccharides on gut microbiota composition and how these effects affect host health.

Anti-Inflammatory Activity of Orally Administered Monostroma nitidum Rhamnan Sulfate against Lipopolysaccharide-Induced Damage to Mouse Organs and Vascular Endothelium

We previously reported that rhamnan sulfate (RS) purified from Monostroma nitidum significantly suppressed lipopolysaccharide (LPS)-induced inflammation in cultured human vascular endothelial cells. Here, we analyzed the effect of orally administered RS on LPS-induced damage to mouse organs and vascular endothelium. RS (1 mg) was orally administered daily to BALB/c mice, 50 μg of LPS was intraperitoneally administered on day 8, and Evans blue was injected into the tail vein 6 h later. After 30 min, LPS-treated mice showed pulmonary Evans blue leakage and elevated plasma levels of liver damage markers, whereas this reaction was suppressed in LPS + RS-treated mice. Immunohistochemical and Western blot analysis of mouse organs 24 h after LPS treatment showed significant neutrophil infiltration into the lung, liver, and jejunum tissues of LPS-treated mice and high expression levels of inflammation-related factors in these tissues. Expression levels of these factors were significantly suppressed in LPS + RS-treated mice. Analysis of lung glycocalyx showed a significant reduction in glycocalyx in LPS-treated mice but not in LPS + RS-treated mice. Levels of syndecan-4, one of the glycocalyx components, decreased in LPS-treated mice and increased in LPS + RS-treated mice. The current results suggest that orally administered RS protects organs and vascular endothelium from LPS-induced inflammation and maintains blood circulation.

Algal polysaccharides and derivatives as potential therapeutics for obesity and related metabolic diseases

The potential and challenges of algal polysaccharides and their derivatives as potential therapeutic agents for obesity and its related metabolic diseases.