Cranberry polyphenols and agave agavins impact gut immune response and microbiota composition while improving gut barrier function, inflammation, and glucose metabolism in mice fed an obesogenic diet

Coated sodium butyrate and vitamin D3 supplementation improve gut health through influencing intestinal immunity, barrier, and microflora in early-stage broilers

BACKGROUND

Intestinal development and function are critical to maintaining sustained broiler growth. The present study aimed to evaluate the effects of coated sodium butyrate (CSB) and vitamin D3 (VD3) on the intestinal immunity, barrier, oxidative stress and microflora in early-stage broilers. In total, 192 one-day-old broilers were assigned to a 2 × 2 factorial design including two dietary supplements at two different levels, in which the main effects were VD3 (3000 or 5000 IU kg-1) and CSB (0 or 1 g kg-1).

RESULTS

The results showed that CSB supplementation increased ileal goblet cells (GCs) numbers, villus height and decreased crypt depth in broilers. CSB increased ileal proliferating cell nuclear antigen expression and high-level VD3 decreased cluster of differentiation 3 expression. CSB reduced serum d-lactate, endotoxin (ET), adrenocorticotropic hormone, corticosterone and malondialdehyde (MDA) concentrations and increased total antioxidant capacity (T-AOC) level. Meanwhile, high-level VD3 decreased serum ET concentration. Furthermore, CSB increased ileal T-AOC, lysozyme (LYZ) and transforming growth factor (TGF)-β and decreased MDA, whereas high-level VD3 decreased ileal MDA and increased secretory immunoglobulin A. CSB up-regulated ileal claudin1, superoxide dismutase 1, TGF-β and LYZ mRNA expression and down-regulated interleukin-1β mRNA expression. CSB combined with high-level VD3 increased ileal Faecalibaculum abundance. Spearman correlation analysis showed that Faecalibaculum was related to the immune and barrier function.

CONCLUSION

Dietary supplementation with CSB and high-level VD3 improved early gut health in broilers by promoting intestinal development, enhancing antioxidant capacity, strengthening barrier function and enhancing the favorable composition of the gut bacterial flora. © 2024 Society of Chemical Industry.

From growth promotion to intestinal inflammation alleviation: Unraveling the potential role of Lactobacillus rhamnosus GCC-3 in juvenile grass carp (Ctenopharyngodon idella)

Lactobacillus rhamnosus is a probiotic, which not only promotes the growth of animals, but also has anti-inflammatory effects. However, the mechanism by which Lactobacillus rhamnosus regulates intestinal immunity is not well comprehended. Hence, the study aimed to research how Lactobacillus rhamnosus affects the intestinal immunity using juvenile grass carp (Ctenopharyngodon idella) as a model. We selected 1800 juvenile grass carp for testing. They were divided into six treatments and fed with six gradients of Lactobacillus rhamnosus GCC-3 (0.0, 0.5, 1.0, 1.5, 2.0, 2.5 g/kg) for 70 days. Enteritis was subsequently induced with dextroside sodium sulfate. Results indicated that dietary Lactobacillus rhamnosus GCC-3 addition improved growth performance. Meanwhile, appropriate levels of Lactobacillus rhamnosus GCC-3 alleviated excessive inflammatory response by down-regulating the expression of TLR4 and NOD receptors, up-regulating the expression of TOR, and then down-regulating the expression of NF-κB. Additionally, appropriate Lactobacillus rhamnosus GCC-3 improved intestinal immunity by reducing pyroptosis triggered by NLRP3 inflammasome and mediated by GSDME. Furthermore, 16 S rRNA sequencing showing appropriate levels of Lactobacillus rhamnosus GCC-3 increased Lactobacillus and Bifidobacterium abundance and decreased Aeromonas abundance. These results suggest that Lactobacillus rhamnosus GCC-3 can alleviate intestinal inflammation through down-regulating NF-κB and up-regulating TOR signaling pathways, as well as by inhibiting pyroptosis.

Short term supplementation with cranberry extract modulates gut microbiota in human and displays a bifidogenic effect

Cranberry is associated with multiple health benefits, which are mostly attributed to its high content of (poly)phenols, particularly flavan-3-ols. However, clinical trials attempting to demonstrate these positive effects have yielded heterogeneous results, partly due to the high inter-individual variability associated with gut microbiota interaction with these molecules. In fact, several studies have demonstrated the ability of these molecules to modulate the gut microbiota in animal and in vitro models, but there is a scarcity of information in human subjects. In addition, it has been recently reported that cranberry also contains high concentrations of oligosaccharides, which could contribute to its bioactivity. Hence, the aim of this study was to fully characterize the (poly)phenolic and oligosaccharidic contents of a commercially available cranberry extract and evaluate its capacity to positively modulate the gut microbiota of 28 human subjects. After only four days, the (poly)phenols and oligosaccharides-rich cranberry extract, induced a strong bifidogenic effect, along with an increase in the abundance of several butyrate-producing bacteria, such as Clostridium and Anaerobutyricum. Plasmatic and fecal short-chain fatty acids profiles were also altered by the cranberry extract with a decrease in acetate ratio and an increase in butyrate ratio. Finally, to characterize the inter-individual variability, we stratified the participants according to the alterations observed in the fecal microbiota following supplementation. Interestingly, individuals having a microbiota characterized by the presence of Prevotella benefited from an increase in Faecalibacterium with the cranberry extract supplementation.

Assessing the Gut Microbiota's Ability to Metabolize Oligomeric and Polymeric Flavan-3-ols from Aronia and Cranberry

Clinical trials investigating the health effects of flavan-3-ols yield heterogeneous results due to interindividual variability in the gut microbiota metabolism. In fact, different groups in the population have similar metabolic profiles following (-)-epicatechin and (+)-catechin gut microbial metabolism and can be regrouped into so-called metabotypes. In this study, the capacity of 34 donors to metabolize polymeric B-type flavan-3-ols from aronia and oligomeric A-type flavan-3-ols from cranberry is investigated by in vitro fecal batch fermentations. Less than 1% of the flavan-3-ols from both sources are converted into microbial metabolites, such as phenyl-γ-valerolactones (PVLs). To further confirm this result, gut microbial metabolites from flavan-3-ols are quantified in urine samples collected from participants, before and after a 4-day supplementation of cranberry extract providing 82.3 mg of flavan-3-ols per day. No significant difference is observed in the urinary excretion of flavan-3-ols microbial metabolites. Hence, it demonstrates by both in vitro and in vivo approaches that flavan-3-ols from aronia and cranberry are poorly degraded by the gut microbiota. The beneficial health impacts of these molecules likely stem from their capacity to affect gut microbiota and their interactions with the gut epithelium, rather than from their breakdown into smaller metabolites.

Nephroprotective effect of cranberry (Vaccinium oxycoccos) in streptozocin-induced diabetic nephropathy in mice

OBJECTIVES

Diabetic nephropathy is a chief reason of mortality particularly in individuals with renal dysfunction. The current research was aimed to assess the nephroprotective portion of Vaccinium oxycoccos toward mice diabetic nephropathy induced by streptozotocin (STZ). V. oxycoccos was purchased and used for hydroalcoholic extraction.

METHODS

Sixty male mice were subjected to STZ-intraperitoneal injection (45 mg/kg). After diabetes induction, mice were divided into five groups of diabetic control (received only STZ), non-diabetic control (received only citrate buffer), two V. oxycoccos treatment (received V. oxycoccos extract (200 and 400 mg/kg) oral daily by gavage), and metformin treatment (received metformin (500 mg/kg) oral daily by gavage). Glucose and weight of mice were checked weekly.

RESULTS

After 28 days, the effect of V. oxycoccos extract on serum and urine parameters were assessed. STZ caused significant decreased in the mice body weight. Mice treated with the V. oxycoccos (400 mg/kg) harbored the lowest weight loss at day 28 (70.2±1.38 g). STZ caused significant increase in the mice FBS. Mice treated with the V. oxycoccos (400 mg/kg) harbored the lowest FBS at day 28 (189.2±1.20 mg/dL). Treatment of mice with V. oxycoccos (400 mg/kg) caused the lowest increase in the levels of cholesterol, HbA1c and triglycerides compared to the diabetic control mice. Compared to the diabetic control group, mice treated with V. oxycoccos (400 mg/kg) had the highest HDL, insulin, SOD, and GSH (p<0.05). The lowest serum BUN, CR, and UR were found in mice treated with V. oxycoccos (400 mg/kg). Anti-inflammatory effects of V. oxycoccos (400 mg/kg) was shown by the lowest TNF-α, IL-6, and TGF-β1 concentration in mice treated with V. oxycoccos (400 mg/kg).

CONCLUSIONS

The current study disclosed that treatment with V. oxycoccos resulted in substantial development in the serum and urine parameters and also antioxidant and anti-inflammatory response of STZ-induced diabetic mice.

Lab-on-chip technologies for exploring the gut-immune axis in metabolic disease

The continued rise in metabolic diseases such as obesity and type 2 diabetes mellitus poses a global health burden, necessitating further research into factors implicated in the onset and progression of these diseases. Recently, the gut-immune axis, with diet as a main regulator, has been identified as a possible role player in their development. Translation of conventional 2D in vitro and animal models is however limited, while human studies are expensive and preclude individual mechanisms from being investigated. Lab-on-chip technology therefore offers an attractive new avenue to study gut-immune interactions. This review provides an overview of the influence of diet on gut-immune interactions in metabolic diseases and a critical analysis of the current state of lab-on-chip technology to study this axis. While there has been progress in the development of "immuno-competent" intestinal lab-on-chip models, with studies showing the ability of the technology to provide mechanical cues, support longer-term co-culture of microbiota and maintain in vivo-like oxygen gradients, platforms which combine all three and include intestinal and immune cells are still lacking. Further, immune cell types and inclusion of microenvironment conditions which enable in vivo-like immune cell dynamics as well as host-microbiome interactions are limited. Future model development should focus on combining these conditions to create an environment capable of hosting more complex microbiota and immune cells to allow further study into the effects of diet and related metabolites on the gut-immune ecosystem and their role in the prevention and development of metabolic diseases in humans.

The role of NLRP6 in the development and progression of neurological diseases

The nervous system possesses the remarkable ability to undergo changes in order to store information; however, it is also susceptible to damage caused by invading pathogens or neurodegenerative processes. As a member of nucleotide-binding oligomerization domain-like receptor (NLR) family, the NLRP6 inflammasome serves as a cytoplasmic innate immune sensor responsible for detecting microbe-associated molecular patterns. Upon activation, NLRP6 can recruit the adapter protein apoptosis-associated speck-like protein (ASC) and the inflammatory factors caspase-1 or caspase-11. Consequently, inflammasomes are formed, facilitating the maturation and secretion of pro-inflammatory cytokines such as inflammatory factors-18 (IL-18) and inflammatory factors-1β (IL-1β). Precise regulation of NLRP6 is crucial for maintaining tissue homeostasis, as dysregulated inflammasome activation can contribute to the development of various diseases. Furthermore, NLRP6 may also play a role in the regulation of extraintestinal diseases. In cells of the brain, such as astrocytes and neurons, NLRP6 inflammasome are also present. Here, the assembly and subsequent activation of caspase-1 mediated by NLRP6 contribute to disease progression. This review aims to discuss the structure and function of NLRP6, explain clearly the mechanisms that induce and activate NLRP6, and explore its role within the central and peripheral nervous system.

Rebaudioside D decreases adiposity and hepatic lipid accumulation in a mouse model of obesity

Overconsumption of added sugars has been pointed out as a major culprit in the increasing rates of obesity worldwide, contributing to the rising popularity of non-caloric sweeteners. In order to satisfy the growing demand, industrial efforts have been made to purify the sweet-tasting molecules found in the natural sweetener stevia, which are characterized by a sweet taste free of unpleasant aftertaste. Although the use of artificial sweeteners has raised many concerns regarding metabolic health, the impact of purified stevia components on the latter remains poorly studied. The objective of this project was to evaluate the impact of two purified sweet-tasting components of stevia, rebaudioside A and D (RebA and RebD), on the development of obesity, insulin resistance, hepatic health, bile acid profile, and gut microbiota in a mouse model of diet-induced obesity. Male C57BL/6 J mice were fed an obesogenic high-fat/high-sucrose (HFHS) diet and orally treated with 50 mg/kg of RebA, RebD or vehicle (water) for 12 weeks. An additional group of chow-fed mice treated with the vehicle was included as a healthy reference. At weeks 10 and 12, insulin and oral glucose tolerance tests were performed. Liver lipids content was analyzed. Whole-genome shotgun sequencing was performed to profile the gut microbiota. Bile acids were measured in the feces, plasma, and liver. Liver lipid content and gene expression were analyzed. As compared to the HFHS-vehicle treatment group, mice administered RebD showed a reduced weight gain, as evidenced by decreased visceral adipose tissue weight. Liver triglycerides and cholesterol from RebD-treated mice were lower and lipid peroxidation was decreased. Interestingly, administration of RebD was associated with a significant enrichment of Faecalibaculum rodentium in the gut microbiota and an increased secondary bile acid metabolism. Moreover, RebD decreased the level of lipopolysaccharide-binding protein (LBP). Neither RebA nor RebD treatments were found to impact glucose homeostasis. The daily consumption of two stevia components has no detrimental effects on metabolic health. In contrast, RebD treatment was found to reduce adiposity, alleviate hepatic steatosis and lipid peroxidation, and decrease LBP, a marker of metabolic endotoxemia in a mouse model of diet-induced obesity.

A Newly Synbiotic Combination Alleviates Obesity by Modulating the Gut Microbiota-Fat Axis and Inhibiting the Hepatic TLR4/NF-κB Signaling Pathway

SCOPE

Obesity has been recognized as a worldwide public health crisis, this is accompanied by dysregulation of the intestinal microbiota and upregulation of liver steatosis and adipose inflammation. Synbiotic as a novel alternative therapy for obesity have recently gained much attention.

METHODS

This study innovatively research the anti-obesity properties of a newly synbiotic composed of Lactobacillus acidophilus, Bifidobacterium infantis and konjac glucomannan oligosaccharides.

RESULTS

The synbiotic treatment can reduce body weight, fat mass, blood sugar, liver steatosis and adipose inflammation in obesity mice fed by high-fat diet (HFD). Meanwhile, synbiotic treatment activated brown adipose tissue and improve energy, glucose and lipid metabolism. In addition, synbiotic treatment not solely enhanced the protection of intestinal barrier, but also ameliorated gut microbiota dysbiosis directly by enhancing beneficial microbes and reducing potentially harmful bacteria. Furthermore, the microbiome phenotype and functional prediction showed that synbiotic treatment can improve the gut microbiota functions involving inflammatory state, immune response, metabolism and pathopoiesia.

CONCLUSION

The synbiotic may be an effective candidate treatment strategy for the clinical prevention and treatment of obesity and other associated metabolic diseases such as hyperlipidemia, nonalcoholic fatty liver diseases by alleviating inflammatory response, regulating energy metabolism and maintaining the balance of intestinal microecology.

Isoxanthohumol improves obesity and glucose metabolism via inhibiting intestinal lipid absorption with a bloom of Akkermansia muciniphila in mice

OBJECTIVE

Polyphenols have health-promoting effects, such as improving insulin resistance. Isoxanthohumol (IX), a prenylated flavonoid found in beer hops, has been suggested to reduce obesity and insulin resistance; however, the mechanism remains unknown.

METHODS

High-fat diet-fed mice were administered IX. We analyzed glucose metabolism, gene expression profiles and histology of liver, epididymal adipose tissue and colon. Lipase activity, fecal lipid profiles and plasma metabolomic analysis were assessed. Fecal 16s rRNA sequencing was obtained and selected bacterial species were used for in vitro studies. Fecal microbiota transplantation and monocolonization were conducted to antibiotic-treated or germ-free (GF) mice.

RESULTS

The administration of IX lowered weight gain, decreased steatohepatitis and improved glucose metabolism. Mechanistically, IX inhibited pancreatic lipase activity and lipid absorption by decreasing the expression of the fatty acid transporter CD36 in the small intestine, which was confirmed by increased lipid excretion in feces. IX administration increased markers of intestinal barrier function, including thickening the mucin layer and increasing caludin-1, a tight-junction related protein in the colon. In contrast, the effects of IX were nullified by antibiotics. As revealed using 16S rRNA sequencing, the microbial community structure changed with a significant increase in the abundance of Akkermansia muciniphila in the IX-treated group. An anaerobic chamber study showed that IX selectively promoted the growth of A. muciniphila while exhibiting antimicrobial activity against some Bacteroides and Clostridium species. To further explore the direct effect of A. muciniphila on lipid and glucose metabolism, we monocolonized either A. muciniphila or Bacteroides thetaiotaomicron to GF mice. A. muciniphila monocolonization decreased CD36 expression in the jejunum and improved glucose metabolism, with decreased levels of multiple classes of fatty acids determined using plasma metabolomic analysis.

CONCLUSIONS

Our study demonstrated that IX prevents obesity and enhances glucose metabolism by inhibiting dietary fat absorption. This mechanism is linked to suppressing pancreatic lipase activity and shifts in microbial composition, notably an increase in A. muciniphila. These highlight new treatment strategies for preventing metabolic syndrome by boosting the gut microbiota with food components.

The synergistic effects of polyphenols and intestinal microbiota on osteoporosis

Osteoporosis is a common metabolic disease in middle-aged and elderly people. It is characterized by a reduction in bone mass, compromised bone microstructure, heightened bone fragility, and an increased susceptibility to fractures. The dynamic imbalance between osteoblast and osteoclast populations is a decisive factor in the occurrence of osteoporosis. With the increase in the elderly population in society, the incidence of osteoporosis, disability, and mortality have gradually increased. Polyphenols are a fascinating class of compounds that are found in both food and medicine and exhibit a variety of biological activities with significant health benefits. As a component of food, polyphenols not only provide color, flavor, and aroma but also act as potent antioxidants, protecting our cells from oxidative stress and reducing the risk of chronic disease. Moreover, these natural compounds exhibit anti-inflammatory properties, which aid in immune response regulation and potentially alleviate symptoms of diverse ailments. The gut microbiota can degrade polyphenols into more absorbable metabolites, thereby increasing their bioavailability. Polyphenols can also shape the gut microbiota and increase its abundance. Therefore, studying the synergistic effect between gut microbiota and polyphenols may help in the treatment and prevention of osteoporosis. By delving into how gut microbiota can enhance the bioavailability of polyphenols and how polyphenols can shape the gut microbiota and increase its abundance, this review offers valuable information and references for the treatment and prevention of osteoporosis.

Bioactive Components in Fruit Interact with Gut Microbes

Fruits contain many bioactive compounds, including polysaccharides, oligosaccharides, polyphenols, anthocyanins, and flavonoids. All of these bioactives in fruit have potentially beneficial effects on gut microbiota and host health. On the one hand, fruit rich in active ingredients can act as substrates to interact with microorganisms and produce metabolites to regulate the gut microbiota. On the other hand, gut microbes could promote health effects in the host by balancing dysbiosis of gut microbiota. We have extensively analyzed significant information on bioactive components in fruits based on Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA). Although the deep mechanism of action of bioactive components in fruits on gut microbiota needs further study, these results also provide supportive information on fruits as a source of dietary active ingredients to provide support for the adjunctive role of fruits in disease prevention and treatment.

Plasma Bacterial DNA Load as a Potential Biomarker for the Early Detection of Colorectal Cancer: A Case-Control Study

The gut microbiota has gained increasing attention in recent years due to its significant impact on colorectal cancer (CRC) development and progression. The recent detection of bacterial DNA load in plasma holds promise as a potential non-invasive approach for early cancer detection. The aim of this study was to examine the quantity of bacterial DNA present in the plasma of 50 patients who have CRC in comparison to 40 neoplastic disease-free patients, as well as to determine if there is a correlation between the amount of plasma bacterial DNA and various clinical parameters. Plasma bacterial DNA levels were found to be elevated in the CRC group compared to the control group. As it emerged from the logistic analysis (adjusted for age and gender), these levels were strongly associated with the risk of CRC (OR = 1.02, p < 0.001, 95% C.I.: 1.01-1.03). Moreover, an association was identified between a reduction in tumor mass and the highest tertile of plasma bacterial DNA. Our findings indicate that individuals with CRC displayed a higher plasma bacterial DNA load compared to healthy controls. This observation lends support to the theory of heightened bacterial migration from the gastrointestinal tract to the bloodstream in CRC. Furthermore, our results establish a link between this phenomenon and the size of the tumor mass.

In Search of a Function for the N6-Methyladenosine in Epitranscriptome, Autophagy and Neurodegenerative Diseases

Changes in epitranscriptome with N6-methyladenine (m6A) modification could be involved in the development of multiple diseases, which might be a prevalent modification of messenger RNAs (mRNAs) in eukaryotes. The m6A modification might be performed through the action of methyltransferases, demethylases, and methylation-binding proteins. Importantly, the m6A methylation may be associated with various neurological disorders including Alzheimer's disease (AD), Parkinson's disease (PD), depression, aging-related diseases, and/or aging itself. In addition, the m6A methylation might functionally regulate the eukaryotic transcriptome by influencing the splicing, export, subcellular localization, translation, stability, and decay of mRNAs. Neurodegenerative diseases may possess a wide variety of phenotypes, depending on the neurons that degenerate on occasion. Interestingly, an increasing amount of evidence has indicated that m6A modification could modulate the expression of autophagy-related genes and promote autophagy in neuronal cells. Oxidative stresses such as reactive oxygen species (ROS) could stimulate the m6A RNA methylation, which may also be related to the regulation of autophagy and/or the development of neurodegenerative diseases. Both m6A modification and autophagy could also play critical roles in regulating the health condition of neurons. Therefore, a comprehensive understanding of the m6A and autophagy relationship in human diseases may benefit in developing therapeutic strategies in the future. This paper reviews advances in the understanding of the regulatory mechanisms of m6A modification in the occurrence and development of neurodegenerative diseases and/or aging, discussing the possible therapeutic procedures related to mechanisms of m6A RNA methylation and autophagy.

Dietary Patterns, Gut Microbiota Remodeling, and Cardiometabolic Disease

The cardiovascular and metabolic disorders, collectively known as cardiometabolic disease (CMD), are high morbidity and mortality pathologies associated with lower quality of life and increasing health-care costs. The influence of the gut microbiota (GM) in dictating the interpersonal variability in CMD susceptibility, progression and treatment response is beginning to be deciphered, as is the mutualistic relation established between the GM and diet. In particular, dietary factors emerge as pivotal determinants shaping the architecture and function of resident microorganisms in the human gut. In turn, intestinal microbes influence the absorption, metabolism, and storage of ingested nutrients, with potentially profound effects on host physiology. Herein, we present an updated overview on major effects of dietary components on the GM, highlighting the beneficial and detrimental consequences of diet-microbiota crosstalk in the setting of CMD. We also discuss the promises and challenges of integrating microbiome data in dietary planning aimed at restraining CMD onset and progression with a more personalized nutritional approach.

The role of intestinal microbiota and microRNAs in the anti-inflammatory effects of cranberry: from pre-clinical to clinical studies

Cranberries have known anti-inflammatory properties, which extend their benefits in the context of several chronic diseases. These benefits highly rely on the polyphenol profile of cranberries, one of few foods rich in A-type proanthocyanidin (PAC). A-type PAC comprises flavan-3-ol subunits with an additional interflavan ether bond in the conformational structure of the molecule, separating them from the more commonly found B-type PAC. PACs with a degree of polymerization higher than three are known to reach the colon intact, where they can be catabolyzed by the gut microbiota and biotransformed into lower molecular weight organic acids that are available for host absorption. Gut microbiota-derived metabolites have garnered much attention in the past decade as mediators of the health effects of parent compounds. Though, the mechanisms underlying this phenomenon remain underexplored. In this review, we highlight emerging evidence that postulates that polyphenols, including ones derived from cranberries, and their metabolites could exert anti-inflammatory effects by modulating host microRNAs. Our review first describes the chemical structure of cranberry PACs and a pathway for how they are biotransformed by the gut microbiota. We then provide a brief overview of the benefits of microbial metabolites of cranberry in the intestinal tract, at homeostasis and in inflammatory conditions. Finally, we discuss the role of microRNAs in intestinal health and in response to cranberry PAC and how they could be used as targets for the maintenance of intestinal homeostasis. Most of this research is pre-clinical and we recognize that conducting clinical trials in this context has been hampered by the lack of reliable biomarkers. Our review discusses the use of miRNA as biomarkers in this context.

Vaccinium as Potential Therapy for Diabetes and Microvascular Complications

Diabetes mellitus is one of the most critical global health concerns, with a fast-growing prevalence. The incidence of diabetic vascular complications is also rapidly increasing, exacerbating the burden on individuals with diabetes and the consumption of public medical resources. Despite the overall improvements in the prevention, diagnosis, and treatment of diabetic microvascular complications in recent years, safe and effective alternative or adjunctive therapies are urgently needed. The mechanisms underlying diabetic vascular complications are complex, with hyperglycemia-induced oxidative stress and inflammation being the leading causes. Therefore, glycemic control, antioxidation, and anti-inflammation are considered the main targets for the treatment of diabetes and its vascular comorbidities. Vaccinium L. (Ericaceae) is a genus of plants enriched with polyphenolic compounds in their leaves and fruits. Vaccinium and its extracts have demonstrated good bioactivity in reducing blood glucose, oxidative stress, and inflammation, making them excellent candidates for the management of diabetes and diabetic vascular complications. Here, we review recent preclinical and clinical studies on the potential effect of Vaccinium on ameliorating diabetes and diabetic complications, particularly diabetic kidney disease and diabetic retinopathy.

Polyphenols as Drivers of a Homeostatic Gut Microecology and Immuno-Metabolic Traits of Akkermansia muciniphila: From Mouse to Man

Akkermansia muciniphila is a mucosal symbiont considered a gut microbial marker in healthy individuals, as its relative abundance is significantly reduced in subjects with gut inflammation and metabolic disturbances. Dietary polyphenols can distinctly stimulate the relative abundance of A. muciniphila, contributing to the attenuation of several diseases, including obesity, type 2 diabetes, inflammatory bowel diseases, and liver damage. However, mechanistic insight into how polyphenols stimulate A. muciniphila or its activity is limited. This review focuses on dietary interventions in rodents and humans and in vitro studies using different phenolic classes. We provide critical insights with respect to potential mechanisms explaining the effects of polyphenols affecting A. muciniphila. Anthocyanins, flavan-3-ols, flavonols, flavanones, stilbenes, and phenolic acids are shown to increase relative A. muciniphila levels in vivo, whereas lignans exert the opposite effect. Clinical trials show consistent findings, and high intervariability relying on the gut microbiota composition at the baseline and the presence of multiple polyphenol degraders appear to be cardinal determinants in inducing A. muciniphila and associated benefits by polyphenol intake. Polyphenols signal to the AhR receptor and impact the relative abundance of A. muciniphila in a direct and indirect fashion, resulting in the restoration of intestinal epithelial integrity and homeostatic crosstalk with the gut microbiota by affecting IL-22 production. Moreover, recent evidence suggests that A. muciniphila participates in the initial hydrolysis of some polyphenols but does not participate in their complete metabolism. In conclusion, the consumption of polyphenol-rich foods targeting A. muciniphila as a pivotal intermediary represents a promising precision nutritional therapy to prevent and attenuate metabolic and inflammatory diseases.