Secoisolariciresinol Diglucoside Exerts Anti-Inflammatory and Antiapoptotic Effects through Inhibiting the Akt/IκB/NF-κB Pathway on Human Umbilical Vein Endothelial Cells

Association of dietary intake of polyphenols, lignans, and phytosterols with immune-stimulating microbiota and COVID-19 risk in a group of Polish men and women

Objectives

Devastating consequences of COVID-19 disease enhanced the role of promoting prevention-focused practices. Among targeted efforts, diet is regarded as one of the potential factors which can affect immune function and optimal nutrition is postulated as the method of augmentation of people's viral resistance. As epidemiological evidence is scarce, the present study aimed to explore the association between dietary intake of total polyphenols, lignans and plant sterols and the abundance of immunomodulatory gut microbiota such as Enterococcus spp. and Escherichia coli and the risk of developing COVID-19 disease.

Methods

Demographic data, dietary habits, physical activity as well as the composition of body and gut microbiota were analyzed in a sample of 95 young healthy individuals. Dietary polyphenol, lignan and plant sterol intakes have been retrieved based on the amount of food consumed by the participants, the phytochemical content was assessed in laboratory analysis and using available databases.

Results

For all investigated polyphenols and phytosterols, except campesterol, every unit increase in the tertile of intake category was associated with a decrease in the odds of contracting COVID-19. The risk reduction ranged from several dozen percent to 70 %, depending on the individual plant-based chemical, and after controlling for basic covariates it was statistically significant for secoisolariciresinol (OR = 0.28, 95% CI: 0.11-0.61), total phytosterols (OR = 0.47, 95% CI: 0.22-0.95) and for stigmasterols (OR = 0.34, 95% CI: 0.14-0.72). We found an inverse association between increased β-sitosterol intake and phytosterols in total and the occurrence of Escherichia coli in stool samples outside reference values, with 72% (OR = 0.28, 95% CI: 0.08-0.86) and 66% (OR = 0.34, 95% CI: 0.10-1.08) reduced odds of abnormal level of bacteria for the highest compared with the lowest tertile of phytochemical consumption. Additionally, there was a trend of more frequent presence of Enterococcus spp. at relevant level in people with a higher intake of lariciresinol.

Conclusion

The beneficial effects of polyphenols and phytosterols should be emphasized and these plant-based compounds should be regarded in the context of their utility as antiviral agents preventing influenza-type infections.

Secoisolariciresinol diglucoside Ameliorates Osteoarthritis via Nuclear factor-erythroid 2-related factor-2/ nuclear factor kappa B Pathway: In vitro and in vivo experiments

Osteoarthritis (OA) is an age-related joint disease in which inflammation and extracellular matrix (ECM) degradation play a crucial role in the destruction of articular cartilage. Secoisolariciresinol diglucoside (SDG), the main lignan in wholegrain flaxseed, which has been reported to remarkably suppress inflammation and oxidative stress, may have potential therapeutic value in OA. In this study, the effect and mechanism of SDG against cartilage degeneration were verified in the destabilization of the medial meniscus (DMM) and collagen-induced (CIA) arthritis models and interleukin-1β (IL-1β)-stimulated osteoarthritis chondrocyte models. From our experiments, SDG treatment downregulated the expression of pro-inflammatory factors induced by IL-1β in vitro, including inducible nitric oxide synthase (INOS), cyclooxygenase-2 (COX2), tumor necrosis factor (TNF-α), and interleukin 6 (IL-6). Additionally, SDG promoted the expression of collagen II (COL2A1) and SRY-related high-mobility-group-box gene 9(SOX9), while suppressing the expression of a disintegrin and metalloproteinase with thrombospondin motifs 5(ADAMTS5) and matrix metalloproteinases 13(MMP13), which leads to catabolism. Consistently, in vivo, SDG has been identified to have chondroprotective effects in DMM-induced and collagen-induced arthritis models. Mechanistically, SDG exerted its anti-inflammation and anti-ECM degradation effects by activating the Nrf2/HO-1 pathway and inhibiting the nuclear factor kappa B (NF-κB) pathway. In conclusion, SDG ameliorates the progression of OA via the Nrf2/NF-κB pathway, which indicates that SDG may have therapeutic potential for OA.

Secoisolariciresinol diglucoside-derived metabolite, enterolactone, attenuates atopic dermatitis by suppressing Th2 immune response

Atopic dermatitis (AD) is a severe inflammatory skin disease caused by a combination of genetic, immune, and environmental factors. Intestinal microbiome disorders and changes in the immune microenvironment are associated with AD. We observed that gut bacterial metabolite enterolactone (ENL) was significantly reduced in AD model mice. Notably, patients with early childhood-onset AD exhibited decreased sera ENL level compared to the healthy controls, and the ENL level was negatively correlated with the SCORAD index. Secoisolariciresinol-diglycoside (SDG) is a natural dietary lignan of flaxseeds that can be converted by intestinal bacteria to ENL. Repeated applications of 2,4-dinitrochlorobenzene (DNCB) were performed on the ear and dorsal skin of mice to induce AD-like symptoms and skin lesions. Oral administration of SDG significantly decreased serum IgE levels and limited skin inflammation in the DNCB-induced AD mice. In addition, SDG treatment strongly limited the Th2 responses in AD mice. Moreover, we demonstrated that the IL-4 production was significantly suppressed by ENL under Th2 polarization conditions via the JAK-STAT6 signaling pathway in a concentration-dependent manner. We concluded that SDG and its derived metabolite ENL ameliorated AD development by reducing the Th2 immune response. These results suggested that SDG and ENL might be exploited as potential therapeutic candidates for AD treatment.

Feeding Fiber-Bound Polyphenol Ingredients at Different Levels Modulates Colonic Postbiotics to Improve Gut Health in Cats

Simple Summary

Food eaten by humans or companion animals is broken down by enzymes produced by the host and also by bacteria present in the large intestine of the host. Many of the compounds produced can have beneficial effects on the host’s health. Previous studies in dogs evaluated changes after they ate food containing a fiber bundle made of pecan shells, flax seed, and powders from cranberry, citrus, and beet. These studies showed that bacteria in the large intestine switched from digesting mainly protein to digesting mainly carbohydrates resulting in production of compounds with beneficial properties. The study presented here tested this fiber bundle in cats to see which compounds and/or bacteria in the feces changed. After cats consumed food containing the fiber bundle, several compounds associated with beneficial health effects increased, and some compounds that indicate the breakdown of protein decreased. In contrast, little change in fecal bacteria was observed following consumption of food with the fiber bundle. Overall, these findings indicate that, similar to the dog studies, bacteria in the large intestine of cats were able to digest the fiber bundle to make compounds that may contribute to host health and also shifted to digestion of carbohydrates instead of protein.

Abstract

Consumption of fiber in its different forms can result in positive health effects. Prior studies in dogs found that addition of a fiber bundle (composed of pecan shells, flax seed, and powders of cranberry, citrus, and beet) to food resulted in a shift in fecal bacterial metabolism from proteolysis to saccharolysis. The present study evaluated the changes in fecal metabolites and microbiota in healthy cats following the consumption of this fiber bundle. Following a 28-day pre-feed period, 56 healthy adult cats received food with none or one of three concentrations (0%, 1%, 2%, and 4%) of the fiber bundle for a 31-day period. In cats that consumed the 4% fiber bundle, levels of ammonium and fecal branched-chain fatty acids (BCFAs) decreased from baseline and compared with the other groups. Addition of any level of the fiber bundle resulted in increases in beneficial metabolites: polyphenols hesperidin, hesperetin, ponciretin, secoisolariciresinol diglucoside, secoisolariciresinol, and enterodiol. Little change in fecal microbiota was observed. Since higher levels of ammonia and BCFAs indicate putrefactive metabolism, the decreases in these with the 4% fiber bundle indicate a shift toward saccharolytic metabolism despite little change in the microbiota composition.

Key Genes Associated With Non-Alcoholic Fatty Liver Disease and Polycystic Ovary Syndrome

Background: Polycystic ovary syndrome (PCOS) is the most common metabolic and endocrinopathies disorder in women of reproductive age and non-alcoholic fatty liver (NAFLD) is one of the most common liver diseases worldwide. Previous research has indicated potential associations between PCOS and NAFLD, but the underlying pathophysiology is still not clear. The present study aims to identify the differentially expressed genes (DEGs) between PCOS and NAFLD through the bioinformatics method, and explore the associated molecular mechanisms.

Methods: The microarray datasets GSE34526 and GSE63067 were downloaded from Gene Expression Omnibus (GEO) database and analyzed to obtain the DEGs between PCOS and NAFLD with the GEO2R online tool. Next, the Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis for the DEGs were performed. Then, the protein-protein interaction (PPI) network was constructed and the hub genes were identified using the STRING database and Cytoscape software. Finally, NetworkAnalyst was used to construct the network between the targeted microRNAs (miRNAs) and the hub genes.

Results: A total of 52 genes were identified as DEGs in the above two datasets. GO and KEGG enrichment analysis indicated that DEGs are mostly enriched in immunity and inflammation related pathways. In addition, nine hub genes, including TREM1, S100A9, FPR1, NCF2, FCER1G, CCR1, S100A12, MMP9, and IL1RN were selected from the PPI network by using the cytoHubba and MCODE plug-in. Then, four miRNAs, including miR-20a-5p, miR-129-2-3p, miR-124-3p, and miR-101-3p, were predicted as possibly the key miRNAs through the miRNA-gene network construction.

Conclusion: In summary, we firstly constructed a miRNA-gene regulatory network depicting interactions between the predicted miRNA and the hub genes in NAFLD and PCOS, which provides novel insights into the identification of potential biomarkers and valuable therapeutic leads for PCOS and NAFLD.

Feeding Fiber-Bound Polyphenol Ingredients at Different Levels Modulates Colonic Postbiotics to Improve Gut Health in Dogs

Simple Summary

Microbes present in the large intestine of humans and companion animals produce bioactive metabolites from host-ingested food. These bioactive metabolites can influence host health. A prior study in dogs that were healthy or had chronic enteritis/gastroenteritis showed that stool quality improved when they ate food containing a fiber bundle made from fibers of pecan shells, flax seed, cranberry, citrus, and beet. In addition, eating food containing the fiber bundle resulted in the gut bacteria shifting from digesting mainly protein to digesting mainly carbohydrates. The present study tested the impact of the fiber bundle at a lower range of concentrations in dogs. Fecal levels of several bioactive metabolites with beneficial antioxidant or anti-inflammatory properties increased after dogs consumed food with the fiber bundle, though no changes in the bacteria or their functional pathways were observed. Stool quality remained in the acceptable range. These results suggest that the gut bacteria were able to digest the fiber bundle to produce beneficial bioactive metabolites to improve host health.

Abstract

This study assessed changes in canine fecal metabolites and microbiota with the consumption of foods with increasing concentrations of a fiber bundle including pecan shells, flax seed, and powders of cranberry, citrus, and beet that was previously shown (at 14% w/w) to improve stool quality, shift fecal bacterial metabolism from proteolysis to saccharolysis, increase abundance of saccharolytic bacteria, and decrease abundance of proteolytic bacteria. In this study, 48 healthy adult dogs were split evenly to consume different inclusion levels (0%, 1%, 2%, and 4%) of the fiber bundle for a 31-day period following a 28-day pre-feed period. Increases from baseline in the fecal short-chain fatty acids butyric acid, valeric acid, and hexanoic acid were observed only in the dogs that consumed the food with the 4% fiber bundle. With addition of any level of the fiber bundle, increases were seen in the polyphenols hesperidin, hesperetin, ponciretin, secoisolariciresinol diglucoside, secoisolariciresinol, and enterodiol. However, fecal microbiota and their metabolism, and stool scores were largely unaffected by the fiber bundle. Overall, addition of the fiber bundle appeared to increase bioactive metabolites of increased antioxidant and anti-inflammatory potency for beneficial to health and, at levels ≥4%, shifted gut bacterial metabolism toward saccharolysis.