Production of immunoregulatory polysaccharides from Crassostrea hongkongensis and their positive effects as a nutrition factor in modulating the effectiveness and toxicity of 5-FU chemotherapy in mice

A large-scale study integrating nutritional indicators and clinicopathological parameters to evaluate prognosis, follow-up, and postoperative chemotherapy decisions in rectal cancer patients

OBJECTIVE

The aim of this study was to evaluate the role of nutritional indicators and clinicopathological parameters in predicting the progression and prognosis for pathological stage II-III rectal cancer (RC) patients without neoadjuvant radiotherapy. In addition, we sought to explore the high-risk population who may require postoperative chemotherapy.

METHODS

A total of 894 consecutive RC patients were enrolled in this study. Univariate and multivariate Cox analysis were performed to identify the independent risk factors for PFS and OS. The nomogram and calibration curves were conducted according to multivariable analysis result. Kaplan-Meier survival curves and log-rank tests were performed for different groups. Finally, random survival forest (RSF) model was developed to predict the probability of progression.

RESULTS

Our results revealed that CEA level, pathological stage, tumor deposit, and PNI were independently associated with PFS in RC patients. Similarly, the results indicated that CEA level, pathological stage, tumor deposit, PNI, and NRI were independently associated with OS. RSF model revealed that group 1 had the highest risk of progression at the 12th month of follow-up, group 2 had the highest risk of progression at the 15th month of follow-up, while group 3 had the highest risk of progression at the 9th month of follow-up. Besides, subgroup analysis suggested that the high-risk group needs postoperative adjuvant chemotherapy, while patients in the low- and moderate-risk groups may not need postoperative adjuvant chemotherapy. Finally, we validated our results with the SEER database.

CONCLUSIONS

In conclusion, we demonstrated that preoperative nutritional indicator and clinicopathological parameters could act as auxiliary prognostication tools for RC patients without neoadjuvant radiotherapy. We also established follow-up strategies for different groups of patients. Collectively, incorporating nutritional assessment into risk stratification for RC resection is crucial and should be an integral part of preoperative planning.

Oyster (Crassostrea gigas) Polysaccharide Ameliorates High-Fat-Diet-Induced Oxidative Stress and Inflammation in the Liver via the Bile Acid-FXR-AMPKα Pathway

Oyster polysaccharides (OPS) have a variety of biological activities. In this study, we aimed to investigate the potential mechanisms of OPS to ameliorate hepatic oxidative stress and inflammation in mice induced by a high-fat diet (HFD). The results showed that OPS reduced the HFD-induced increases in serum transaminase levels and alleviated hepatic oxidative stress and inflammation. Moreover, OPS regulated bile acid metabolism and increased bile acid content in the liver, serum, and feces. Serum bile acid profile results indicated that OPS reduced levels of chenodeoxycholic acid, deoxycholic acid, and lithocholic acid associated with high-affinity agonists of Farnesol X receptor (FXR). Western blot analysis showed that OPS accelerated bile acid metabolism by downregulating hepatic FXR expression and promoting its downstream CYP7A1, CYP27A1, and CYP8B1 protein expression. Meanwhile, OPS ameliorated oxidative stress and inflammation in the liver by modulating FXR-AMPKα-Nrf2/NF-κB signaling to reduce p-IκBα/IκBα, p-NF-κB p65/NF-κB p65, IL-1β, and TNF-α expression and increase p-Nrf2/Nrf2, HO-1, and NQO-1 expression. This study was the first to explore the possible mechanism of OPS in improving liver oxidative stress and inflammation from the perspective of bile acid metabolism, providing a theoretical basis for OPS as a new source of functional food.

Oyster (Crassostrea gigas) polysaccharide ameliorates obesity in association with modulation of lipid metabolism and gut microbiota in high-fat diet fed mice

Oyster is nutritious shellfish, wildly consumed throughout the world. Its polysaccharide (OPS) has various bioactivity. In the present study, the anti-obesity effect of OPS was evaluated in obese mice induced by a high-fat diet (HFD). The results showed that OPS significantly alleviated weight gain, dyslipidemia, and metabolic endotoxemia of obese mice, and accelerated the production of short-chain fatty acids. OPS also regulated lipid metabolism of adipose and liver by activating the expression of p-AMPKα to further down-regulate the expression of SREBP-1c, PPARγ, and p-ACC-1. 16S rRNA results indicated that OPS corrected HFD-induced gut microbiota dysbiosis by enriching beneficial bacteria (Bifidobacterium, Lactobacillus, Dobosiella, and Faecalibaculum) and decreasing harmful bacteria (Erysipelatoclostridium, Helicobacter, and Mucispirillum). In summary, these results revealed that OPS could serve as a potential prebiotic to improve obesity.

In vitro simulated digestion and fermentation characteristics of polysaccharide from oyster (Crassostrea gigas), and its effects on the gut microbiota

Oyster is a kind of nutritious shellfish widely consumed globally, and its polysaccharide (OPS) has been verified to have strong functional activity. However, it is still unclear about the specific digestion and prebiotic properties of OPS. In the present study, the digestion and fermentation properties of OPS and its effect on gut microbiota were evaluated using simulated digestion (saliva, stomach, and small intestine) and fermentation models in vitro. The results showed that the molecular weight (Mw) of OPS decreased from 5.73 × 10⁶ to 4.35 × 10⁶ Da, and the reducing sugar content increased from 0.043 to 0.096 mg/mL, indicating that OPS was partially degraded during the saliva-gastrointestinal digestion. During fermentation, the Mw and carbohydrate residue of indigestible OPS (OPSI) decreased, and free monosaccharides were released, suggesting that OPSI could be further degraded and utilized by gut microbiota. Notably, OPSI could regulate the composition and diversity of the microbial community, especially increase the abundance of beneficial bacteria such as Bacteroides, Prevotella, and Faecalibacterium. Additionally, after fermentation for 24 h, OPSI promoted the production of short-chain fatty acids (SCFAs), and acetic acid, propionic acid, and n-butyric acid were the main metabolites. These results provided a reference for the digestive characteristics of OPS and revealed that OPS might be a potential prebiotic to prevent diseases by improving intestinal health.

Beneficial Effects of Polysaccharides on the Epithelial Barrier Function in Intestinal Mucositis

Intestinal mucositis is a clinically relevant side effect of anticancer therapies. It is experienced by 60–100% of patients undergoing treatment with high doses of chemotherapy, radiation therapy, and bone marrow transplantation. Intestinal mucositis can manifest as pain, weight loss, inflammation, diarrhea, rectal bleeding, and infection; affecting normal nutritional intake and intestinal function. It often impacts adherence to anticancer therapy as it frequently limits patient’s ability to tolerate treatment, causing schedule delays, interruptions, or premature discontinuation. In some cases, local and systemic secondary infections are observed, increasing the costs toward medical care and hospitalization. Several strategies for managing mucositis are available which do not always halt this condition. In this context, new therapeutic strategies are under investigation to prevent or treat intestinal mucositis. Polysaccharides from natural resources have recently become promising molecules against intestinal damage due to their ability to promote mucosal healing and their anti-inflammatory actions. These effects are associated with the protection of intestinal mucosa and regulation of microbiota and immune system. This review aims to discuss the recent advances of polysaccharides from natural resources as potential therapies for intestinal mucositis. The source, species, doses, treatment schedules, and mechanisms of action of polysaccharides will be discussed in detail.

Development of Broad-Spectrum Antiviral Agents-Inspiration from Immunomodulatory Natural Products

Developing broad-spectrum antiviral drugs remains an important issue as viral infections continue to threaten public health. Host-directed therapy is a method that focuses on potential targets in host cells or the body, instead of viral proteins. Its antiviral effects are achieved by disturbing the life cycles of pathogens or modulating immunity. In this review, we focus on the development of broad-spectrum antiviral drugs that enhance the immune response. Some natural products present antiviral effects mediated by enhancing immunity, and their structures and mechanisms are summarized here. Natural products with immunomodulatory effects are also discussed, although their antiviral effects remain unknown. Given the power of immunity and the feasibility of host-directed therapy, we argue that both of these categories of natural products provide clues that may be beneficial for the discovery of broad-spectrum antiviral drugs.

Extraction, purification and characterization of sulphated polysaccharide from Bellamya quadrata and its stabilization roles on atherosclerotic plaque

The aim of this paper was to investigate the extraction, purification and characterization of sulphated polysaccharide (BQPS) from Bellamya quadrata and its stabilization roles on atherosclerotic plaque. Firstly, crude polysaccharide (CBQP) from Bellamya quadrata was extracted by protease enzyme assisted extraction. Moreover, its optimal parameters were obtained by the response surface method as follows: the ratio of water to raw material of 24:1, enzyme dosage of 285 U/g, enzymolysis pH value of 4.7 and temperature of 67 °C. Secondly, CBQP was further purified to obtain the target polysaccharide BQPS by Q Sepharose Fast Flow and Sephacryl S-400 gel column chromatography. Then, the characterization of BQPS revealed that it possessed a total polysaccharide content of 91.88 ± 1.23%, sulfuric acid group content of 9.12 ± 1.59% and molecular weight of 91.1 kDa. BQPS was only consisted of glucose without any proteins. Finally, BQPS was confirmed to have a significant stabilizing effect on atherosclerotic plaque and its mechanism was related to the selective promotion of autophagy with the precisely right strength.

Prognostic impact of preoperative immunonutritional status in rectal mucinous adenocarcinoma

Aim: To explore the impact of preoperative the albumin-to-globulin ratio (AGR) and the prognostic nutritional index (PNI) on prognosis in rectal mucinous adenocarcinoma (MAC). Methods: A total of 128 patients were included. Results: According to the X-tile analysis, cutoff values of AGR and PNI were 1.1 and 43.8. Preoperative AGR (p = 0.041), preoperative PNI (p = 0.036) and pTNM stage (p = 0.003) were independently associated with overall survival in rectal MAC patients. Distance from the anal verge (p = 0.005), preoperative AGR (p = 0.021), preoperative PNI (p = 0.007) and pTNM stage (p < 0.001) were significantly associated with disease-free survival in rectal MAC patients. Nomograms for overall survival and disease-free survival were developed (C-index: 0.739 and 0.764). Conclusion: Preoperative AGR and PNI can act as effective predictors for survival for rectal MAC patients.

The purification and identification of immunoregulatory peptides from oyster (Crassostrea hongkongensis) enzymatic hydrolysate

The identification of two peptides with immunoregulatory activity from oysters was performed.

Methods of extraction, separation, purification, structural characterization for polysaccharides from aquatic animals and their major pharmacological activities

The further development of fishery resources is a hotspot in the development of the fishery industry. However, how to develop aquatic animal resources deeply is a key point to be solved in the fishery industry. Over the past decades, numerous aquatic animals have gained great attention in the development and utilization of their bioactive molecules which are of therapeutic applications as nutraceuticals and pharmaceuticals. Recent research revealed that aquatic animals are composed of many vital moieties, such as polysaccharides and proteins, which provide health benefits beyond basic nutrition. In particular, aquatic animal polysaccharides are gaining worldwide popularity owing to their high content, ease of extraction, specific structure, few side effects, prominent therapeutic potential and incorporation in functional foods and dietary supplements. Thus, tremendous research on the isolation, identification and bioactivities of polysaccharides has been carried out. This review presents comprehensive viewpoints on extraction, separation, purification, structural characterization and bioactivity of various polysaccharides from aquatic animals, such as sea cucumber, abalone, oyster and mussels. In addition, this review profiled a brief knowledge on both current challenges and future scope in aquatic animal polysaccharides field. The review will be a direction of deep processing in fishery resources, which is a hotspot, but technical bottleneck. Furthermore, the review could be served as a useful reference material for further investigation, production and application of polysaccharides from aquatic animals in functional foods and therapeutic agents.

Protective Effects of Enteral Nutrition Supplemented with Crassostrea hongkongensis Polysaccharides Against 5-Fluorouracil-Induced Intestinal Mucosal Damage in Rats

Chemotherapeutics, including 5-fluorouracil (5-FU), often damage the intestinal mucosal barrier and cause intestinal mucositis (IM). Supplementation with immunoregulatory polysaccharides from Crassostrea hongkongensis has been shown to positively influence the effectiveness and toxicity of 5-FU. Therefore, we studied the effects of oyster polysaccharides on 5-FU-induced intestinal mucosal damage in rats. The C_30-60% ethanol-precipitated fraction of polysaccharides promoted IEC-6 cell proliferation and exhibited a maximal effect at a 0.0195 mg/mL concentration. Moreover, treatment with C_30-60% polysaccharide-based nutrition formula (OPNF) partially prevented the 5-FU-induced degenerative changes in the histology and ultrastructure of small intestinal mucosa. In addition, the endotoxin level of rats fed with 5-FU and OPNF decreased to the normal control level. Furthermore, the 5-FU-induced increase of proinflammatory cytokine interleukin (IL)-2 and the decrease of anti-inflammatory cytokine IL-10 level in the peripheral blood were significantly attenuated by OPNF administration. In conclusion, Oyster C_30-60% polysaccharides can ameliorate 5-FU-induced IM by partially preventing mucosal damage, reducing inflammation, and promoting immunity.

Antitumor immunostimulatory activity of polysaccharides from Panax japonicus C. A. Mey: Roles of their effects on CD4+ T cells and tumor associated macrophages

In this study, chemical properties of polysaccharides from rhizomes of Panax japonicus C. A. Mey (PSPJ) were investigated and the antitumor immunostimulatory activity of PSPJ was assessed in mice bearing H22 hepatoma cells. Chemical properties of PSPJ were determined by GC, FT-IR, ¹H NMR and ¹³C NMR analysis. Furthermore, we showed that PSPJ repressed H22 tumor growth in vivo with undetectable toxic effects on tumor-bearing mice. PSPJ upregulated host thymus/spleen indexes and ConA/LPS-induced splenocyte proliferation. Cytotoxic activities of natural killer and CD8+ T cells against H22 hepatoma cells were also elevated. Tumor transplantation led to substantial apoptosis of CD4+ T cells and dysregulation of the cytokine profile secreted by CD4+ T cells. These abnormalities were alleviated by PSPJ in a dose-dependent manner. In tumor-associated macrophages (TAMs), PSPJ reduced the production of immunosuppressive factors such as TGF-β, IL-10 and PEG2. In addition, M2-like polarization of TAMs was also considerably declined in response to PSPJ. Our findings clearly demonstrated the antitumor immunostimulatory activity of PSPJ and supported considering PSPJ as an adjuvant reagent in clinical treatment of malignant diseases.

Immunoenhancement of Edible Fungal Polysaccharides (Lentinan, Tremellan, and Pachymaran) on Cyclophosphamide-Induced Immunosuppression in Mouse Model

Fungal polysaccharides display a variety of important biological activities, including anti-inflammatory, antitumor, and immune-stimulating activities. The aim of present study was to investigate the immunomodulatory effect of fungal polysaccharides on cyclophosphamide-induced immunosuppression in mice. Mice were pretreated orally with lentinan, tremellan, pachymaran, or a mixture of the three, respectively. The results showed that pretreatments with polysaccharides significantly increased the thymus index in cyclophosphamide-induced immunosuppression mice. The level of the cytokine IL-10 in sera of cyclophosphamide-induced mice was decreased after pretreatments of polysaccharides. Flow cytometry results showed that pretreatments with polysaccharides enhanced the phagocytosis of peritoneal macrophages in mice. The increased levels of serum antibody IgG and IgM were observed in the groups pretreated with polysaccharides. Our work demonstrated that the treatment of polysaccharides elicited strong immune activity and a protective effect against cyclophosphamide-induced immunosuppression.

Preoperative albumin-to-globulin ratio and prognostic nutrition index predict prognosis for glioblastoma

Objective

Impaired immunonutritional status has disadvantageous effects on outcomes for cancer patients. Preoperative albumin-to-globulin ratio (AGR) and the prognostic nutrition index (PNI) have been used as prognostic factors in various cancers. We aimed to evaluate the clinical significance of the AGR and PNI in glioblastoma.

Materials and methods

This retrospective analysis involved 166 patients. Demographic, clinical, and laboratory data were collected. AGR and the PNI were calculated as AGR = albumin/(total serum protein − albumin) and PNI = albumin (g/L) + 5 × total lymphocyte count (10⁹/L). Overall survival (OS) was estimated by Kaplan–Meier analysis. Receiver-operating characteristic analysis was used to assess the predictive ability of AGR and the PNI. Cox proportional-hazard models estimating hazard ratios (HRs) and 95% confidence intervals (CIs) were used for univariable and multivariable survival analyses.

Results

The cutoff values of AGR and PNI were 1.75 and 48. OS was enhanced, with high AGR (>1.75) and the PNI (>48) (P<0.001 for both). Areas under the receiver-operating characteristic curve for AGR and the PNI were 0.68 and 0.631 for 1-year survival and 0.651 and 0.656 for 2-year survival (P<0.05 for all), respectively. On multivariable analyses, both AGR and the PNI were independent predictors of OS (AGR, HR 0.785, 95% CI 0.357–0.979 [P=0.04]; PNI, HR 0.757, 95% CI 0.378–0.985 [P=0.039]). On subgroup analysis, AGR and the PNI were significant prognostic factors for OS in patients with adjuvant therapy (AGR P<0.001; PNI P=0.001).

Conclusion

Preoperative AGR and the PNI may be easy-to-perform and inexpensive indices for predicting OS with glioblastoma. AGR and the PNI could also help in developing good adjuvant-therapy schedules.