Central and peripheral regulations mediated by short-chain fatty acids on energy homeostasis

Gut Microbiota Disorders and Metabolic Syndrome: Tales of a Crosstalk Process

The microbiota in humans consists of trillions of microorganisms that are involved in the regulation of the gastrointestinal tract and immune and metabolic homeostasis. The gut microbiota (GM) has a prominent impact on the pathogenesis of metabolic syndrome (MetS). This process is reciprocal, constituting a crosstalk process between the GM and MetS. In this review, GM directly or indirectly inducing MetS via the host-microbial metabolic axis has been systematically reviewed. Additionally, the specifically altered GM in MetS are detailed in this review. Moreover, short-chain fatty acids (SCFAs), as unique gut microbial metabolites, have a remarkable effect on MetS, and the role of SCFAs in MetS-related diseases is highlighted to supplement the gaps in this area. Finally, the existing therapeutics are outlined, and the superiority and shortcomings of different therapeutic approaches are discussed, in hopes that this review can contribute to the development of potential treatment strategies.

Potential Anti-Obesity Effect of Hazel Leaf Extract in Mice and Network Pharmacology of Selected Polyphenols

Background: Obesity is gradually becoming a widespread health problem, and treatment using natural compounds has seen an increasing trend. As a by-product of hazelnut, hazel leaf is usually disposed of as waste, but it is widely used in traditional and folk medicines around the world. Aim of this study: Based on previous studies, the effects of the regulation of lipid metabolism and the mechanism of hazel leaf polyphenol extraction obesity were investigated. Methods: In this study, a high-fat diet-fed mouse model of obesity and 3T3-L1 preadipocytes were established. The ameliorative effects of the hazel leaf polyphenol extract on obesity and the regulating lipid metabolisms were explored based on network pharmacology, gut microbiota, and molecular docking. Results: Network pharmacology showed that hazel leaf polyphenols may play a role by targeting key targets, including PPARγ, and regulating the PPAR signaling pathway. They significantly improved body weight gain, the liver index, and adiposity and lipid levels; regulated the gut microbiota and short-chain fatty acid contents; down-regulated the expression of lipid synthesis proteins SREBP1c, PPARγ, and C/EBP-α; and up-regulated the expression of p-AMPK in obese mice. They inhibited the differentiation of 3T3-L1 cells, and the expression of related proteins is consistent with the results in vivo. The molecular docking results indicated that gallic acid, quercetin-3-O-beta-D-glucopyranoside, quercetin, myricetin, and luteolin-7-O-glucoside in the hazel leaf polyphenol extract had strong binding activities with PPARγ, C/EBP-α, and AMPK. Conclusions: The results demonstrate that the hazel leaf polyphenol extract can improve obesity by regulating lipid metabolism, which provides a valuable basis for developing health products made from hazel leaf polyphenols in the future.

Empagliflozin rescues lifespan and liver senescence in naturally aged mice

Empagliflozin is currently known to decrease blood glucose levels, delay renal failure, and reduce the risk of cardiovascular death and all-cause mortality in patients with type 2 diabetes with cardiovascular disease. However, the effects of empagliflozin on the lifespan and health of naturally aged organisms are unclear. This study was designed to investigate the impacts and potential mechanisms of empagliflozin on lifespan and liver senescence in naturally aged mice. Our study revealed that empagliflozin improved survival and health in naturally aged mice. Empagliflozin extended the median survival of male mice by 5.9%. Meanwhile, empagliflozin improved learning memory and motor balance, decreased body weight, and downregulated the hepatic protein expression of P21, P16, α-SMA, and COL1A1. Empagliflozin modulates the structure of the intestinal flora, increasing the relative abundance of Lachnospiraceae, Ruminococcaceae, Lactobacillus, Blautia, and Muribaculaceae and decreasing the relative abundance of Erysipelotrichaceae, Turicibacter, and Dubosiella in naturally aged mice. Further exploration discovered that empagliflozin increased the concentration of SCFAs, decreased the levels of the inflammatory factors TNF-α, IL-6, and CXCL9, and regulated the PI3K/AKT/P21 and AMPK/SIRT1/NF-κB pathways, which may represent the underlying mechanisms involved in these beneficial hepatic effects. Taken together, the above results indicated that empagliflozin intervention could be considered a potential strategy for extending lifespan and slowing liver senescence in naturally aged mice.

Fucoidan prevents diabetic cognitive dysfunction via promoting TET2-mediated active DNA demethylation in high-fat diet induced diabetic mice

Diabetic cognitive dysfunction (DCD) refers to cognitive impairment in individuals with diabetes, which is one of the most important comorbidities and complications. Preliminary evidence suggests that consuming sufficient dietary fiber could have benefits for both diabetes and cognitive function. However, the effect and underlying mechanism of dietary fiber on DCD remain unclear. We conducted a cross-sectional analysis using data from NHANES involving 2072 diabetics and indicated a significant positive dose-response relationship between the dietary fiber intake and cognitive performance in diabetics. Furthermore, we observed disrupted cognitive function and neuronal morphology in high-fat diet induced DCD mice, both of which were effectively restored by fucoidan supplementation through alleviating DNA epigenetic metabolic disorders. Moreover, fucoidan supplementation enhanced the levels of short-chain fatty acids (SCFAs) in the cecum of diabetic mice. These SCFAs enhanced TET2 protein stability by activating phosphorylated AMPK and improved TETs activity by reducing the ratio of (succinic acid + fumaric acid)/ α-ketoglutaric acid, subsequently enhancing TET2 function. The positive correlation between dietary fiber intake and cognitive function in diabetics was supported by human and animal studies alike. Importantly, fucoidan can prevent the occurrence of DCD by promoting TET2-mediated active DNA demethylation in the cerebral cortex of diabetic mice.

Interactions between Gut Microbiota and Natural Bioactive Polysaccharides in Metabolic Diseases: Review

The gut microbiota constitutes a complex ecosystem, comprising trillions of microbes that have co-evolved with their host over hundreds of millions of years. Over the past decade, a growing body of knowledge has underscored the intricate connections among diet, gut microbiota, and human health. Bioactive polysaccharides (BPs) from natural sources like medicinal plants, seaweeds, and fungi have diverse biological functions including antioxidant, immunoregulatory, and metabolic activities. Their effects are closely tied to the gut microbiota, which metabolizes BPs into health-influencing compounds. Understanding how BPs and gut microbiota interact is critical for harnessing their potential health benefits. This review provides an overview of the human gut microbiota, focusing on its role in metabolic diseases like obesity, type II diabetes mellitus, non-alcoholic fatty liver disease, and cardiovascular diseases. It explores the basic characteristics of several BPs and their impact on gut microbiota. Given their significance for human health, we summarize the biological functions of these BPs, particularly in terms of immunoregulatory activities, blood sugar, and hypolipidemic effect, thus providing a valuable reference for understanding the potential benefits of natural BPs in treating metabolic diseases. These properties make BPs promising agents for preventing and treating metabolic diseases. The comprehensive understanding of the mechanisms by which BPs exert their effects through gut microbiota opens new avenues for developing targeted therapies to improve metabolic health.

Termite Fungus Comb Polysaccharides Alleviate Hyperglycemia and Hyperlipidemia in Type 2 Diabetic Mice by Regulating Hepatic Glucose/Lipid Metabolism and the Gut Microbiota

Type 2 diabetes (T2D) is a chronic metabolic disorder characterized by hyperglycemia and dyslipidemia. The termite fungus comb is an integral component of nests of termites, which are a global pest. Termite fungus comb polysaccharides (TFCPs) have been identified to possess antioxidant, anti-aging, and immune-enhancing properties. However, their physicochemical characteristics and their role in fighting diabetes have not been previously reported. In the current study, TFCPs were isolated and structurally characterized. The yield of TFCPs was determined to be 2.76%, and it was found to be composed of a diverse array of polysaccharides with varying molecular weights. The hypoglycemic and hypolipidemic effects of TFCPs, as well as their potential mechanisms of action, were investigated in a T2D mouse model. The results demonstrated that oral administration of TFCPs could alleviate fasting blood glucose levels, insulin resistance, hyperlipidemia, and the dysfunction of pancreatic islets in T2D mice. In terms of mechanisms, the TFCPs enhanced hepatic glycogenesis and glycolysis while inhibiting gluconeogenesis. Additionally, the TFCPs suppressed hepatic de novo lipogenesis and promoted fatty acid oxidation. Furthermore, the TFCPs altered the composition of the gut microbiota in the T2D mice, increasing the abundance of beneficial bacteria such as Allobaculum and Faecalibaculum, while reducing the levels of pathogens like Mailhella and Acetatifactor. Overall, these findings suggest that TFCPs may exert anti-diabetic effects by regulating hepatic glucose and lipid metabolism and the composition of the gut microbiota. These findings suggest that TFCPs can be used as a promising functional ingredient for the prevention and treatment of T2D.

Blocking the MIF-CD74 axis augments radiotherapy efficacy for brain metastasis in NSCLC via synergistically promoting microglia M1 polarization

BACKGROUND

Brain metastasis is one of the main causes of recurrence and death in non-small cell lung cancer (NSCLC). Although radiotherapy is the main local therapy for brain metastasis, it is inevitable that some cancer cells become resistant to radiation. Microglia, as macrophages colonized in the brain, play an important role in the tumor microenvironment. Radiotherapy could activate microglia to polarize into both the M1 and M2 phenotypes. Therefore, searching for crosstalk molecules within the microenvironment that can specifically regulate the polarization of microglia is a potential strategy for improving radiation resistance.

METHODS

We used databases to detect the expression of MIF in NSCLC and its relationship with prognosis. We analyzed the effects of targeted blockade of the MIF/CD74 axis on the polarization and function of microglia during radiotherapy using flow cytometry. The mouse model of brain metastasis was used to assess the effect of targeted blockade of MIF/CD74 axis on the growth of brain metastasis.

RESULT

Our findings reveals that the macrophage migration inhibitory factor (MIF) was highly expressed in NSCLC and is associated with the prognosis of NSCLC. Mechanistically, we demonstrated CD74 inhibition reversed radiation-induced AKT phosphorylation in microglia and promoted the M1 polarization in combination of radiation. Additionally, blocking the MIF-CD74 interaction between NSCLC and microglia promoted microglia M1 polarization. Furthermore, radiation improved tumor hypoxia to decrease HIF-1α dependent MIF secretion by NSCLC. MIF inhibition enhanced radiosensitivity for brain metastasis via synergistically promoting microglia M1 polarization in vivo.

CONCLUSIONS

Our study revealed that targeting the MIF-CD74 axis promoted microglia M1 polarization and synergized with radiotherapy for brain metastasis in NSCLC.

Different fat-to-fiber ratios by changing wheat inclusion level impact energy metabolism and microbial structure of broilers

Introduction

Dietary nutrient content is crucial for energy metabolism and development of gut microbiota. Herein, this study aimed to explore the effects of fat-to-fiber ratios on nutrient transporter, energy metabolism and gut microbiota when ingredients composition was altered.

Methods

A total of 240 as-hatched broiler chickens were randomly assigned into three groups including low fat-high dietary fiber (LF-HD), medium fat-medium dietary fiber (MF-MD) and high fat-low dietary fiber (HF-LD), with diets being iso-protein, and broilers were offered the same commercial diets from 21 to 42 d. The data were analyzed using one-way ANOVA of SPSS.

Results and Discussion

Results showed that HF-LD diet significantly increased glucose content and decreased triglyceride in serum of broilers (p < 0.05). The mRNA abundance of jejunal gene involved in glucose transporter and tricarboxylic acid (TCA) cycle was significantly increased in broilers fed with HF-LD diets. Compared with LF-HD, HF-LD had a lower abundance of Anaerofilum and CHKCI001, and an increased proportion of beneficial bacteria such as Alistipes, Catenibacillus, Intestinimonas, Lactobacillus, and Peptococcus (p < 0.05). Functional prediction of these microbial changes indicated that HF-LD diet drove caecal microbiota to participate in carbohydrate metabolism and TCA cycle (p < 0.05). Dietary HF-LD-induced microbiota changes were positively correlated with growth performance of broilers (p < 0.05). Therefore, HF-LD diet increased glucose transporters and energy metabolism in intestine and shaped microbial structure and metabolic pathways, which may benefit the growth performance of broilers.

Local and Systemic Effects of Bioactive Food Ingredients: Is There a Role for Functional Foods to Prime the Gut for Resilience?

Scientific advancements in understanding the impact of bioactive components in foods on the gut microbiota and wider physiology create opportunities for designing targeted functional foods. The selection of bioactive ingredients with potential local or systemic effects holds promise for influencing overall well-being. An abundance of studies demonstrate that gut microbiota show compositional changes that correlate age and disease. However, navigating this field, especially for non-experts, remains challenging, given the abundance of bioactive ingredients with varying levels of scientific substantiation. This narrative review addresses the current knowledge on the potential impact of the gut microbiota on host health, emphasizing gut microbiota resilience. It explores evidence related to the extensive gut health benefits of popular dietary components and bioactive ingredients, such as phytochemicals, fermented greens, fibres, prebiotics, probiotics, and postbiotics. Importantly, this review distinguishes between the potential local and systemic effects of both popular and emerging ingredients. Additionally, it highlights how dietary hormesis promotes gut microbiota resilience, fostering better adaptation to stress-a hallmark of health. By integrating examples of bioactives, this review provides insights to guide the design of evidence-based functional foods aimed at priming the gut for resilience.

Treatment of preterm brain injury via gut-microbiota-metabolite-brain axis

BACKGROUND

Brain injury in preterm infants potentially disrupts critical structural and functional connective networks in the brain. It is a major cause of neurological sequelae and developmental deficits in preterm infants. Interesting findings suggest that the gut microbiota (GM) and their metabolites contribute to the programming of the central nervous system (CNS) during developmental stages and may exert structural and functional effects throughout the lifespan.

AIM

To summarize the existing knowledge of the potential mechanisms related to immune, endocrine, neural, and blood-brain barrier (BBB) mediated by GM and its metabolites in neural development and function.

METHODS

We review the recent literature and included 150 articles to summarize the mechanisms through which GM and their metabolites work on the nervous system. Potential health benefits and challenges of relevant treatments are also discussed.

RESULTS

This review discusses the direct and indirect ways through which the GM may act on the nervous system. Treatment of preterm brain injury with GM or related derivatives, including probiotics, prebiotics, synbiotics, dietary interventions, and fecal transplants are also included.

CONCLUSION

This review summarizes mechanisms underlying microbiota-gut-brain axis and novel therapeutic opportunities for neurological sequelae in preterm infants. Optimizing the initial colonization and microbiota development in preterm infants may represent a novel therapy to promote brain development and reduce long-term sequelae.

Effects of short-chain fatty acids on blood glucose and lipid levels in mouse models of diabetes mellitus: A systematic review and network meta-analysis

Short-chain fatty acids (SCFAs), the main metabolites of gut microbiota, have been associated with lower blood glucose and lipid levels in diabetic mice. However, a comprehensive summary and comparison of the effects of different SCFA interventions on blood glucose and lipid levels in diabetic mice is currently unavailable. This study aims to compare and rank the effects of different types of SCFAs on blood glucose and lipid levels by collecting relevant animal research. A systematic search through PubMed, Embase, Cochrane Library, and Web of Science database was conducted to identify relevant studies from inception to March 17, 2023. Both pairwise meta-analysis and Bayesian network meta-analysis were used for statistical analyses. In total, 18 relevant studies involving 5 interventions were included after screening 3793 citations and 53 full-text articles. Notably, butyrate therapy (mean difference [MD] = -4.52, 95% confidence interval [-6.29, -2.75]), acetate therapy (MD = -3.12, 95% confidence interval [-5.79, -0.46]), and propionate therapy (MD = -2.96, 95% confidence interval [-5.66, -0.26]) significantly reduced the fasting blood glucose levels compared to the control group; butyrate therapy was probably the most effective intervention, with a surface under the cumulative ranking curve (SUCRA) value of 85.5%. Additionally, acetate plus propionate therapy was probably the most effective intervention for reducing total cholesterol (SUCRA = 85.8%) or triglyceride levels (SUCRA = 88.1%). These findings underscore the potential therapeutic implications of SCFAs for addressing metabolic disorders, particularly in type 2 diabetes mellitus.

The immunometabolic reprogramming of microglia in Alzheimer's disease

Alzheimer's disease (AD) is an age-related neurodegenerative disorder (NDD). In the central nervous system (CNS), immune cells like microglia could reprogram intracellular metabolism to alter or exert cellular immune functions in response to environmental stimuli. In AD, microglia could be activated and differentiated into pro-inflammatory or anti-inflammatory phenotypes, and these differences in cellular phenotypes resulted in variance in cellular energy metabolism. Considering the enormous energy requirement of microglia for immune functions, the changes in mitochondria-centered energy metabolism and substrates of microglia are crucial for the cellular regulation of immune responses. Here we reviewed the mechanisms of microglial metabolic reprogramming by analyzing their flexible metabolic patterns and changes that occurred in their metabolism during the development of AD. Further, we summarized the role of drugs in modulating immunometabolic reprogramming to prevent neuroinflammation, which may shed light on a new research direction for AD treatment.

Relationship between Abdominal Volume Index and Body Adiposity Index and Scales of Insulin Resistance and Metabolic Syndrome

Introduction, objectives: Obesity is a global health problem with a great negative impact on health. Among the pathologies caused by obesity are insulin resistance and metabolic syndrome, which constitute an increasingly common health problem in both developed and developing countries. The aim of this study was to examine the relationship between two scales that assess obesity-based on hip circumference-and metabolic syndrome (MetS) and insulin resistance risk scales as predictors of these alterations.

MATERIALS, METHODS

A descriptive, cross-sectional study was carried out on 193,462 workers from different Spanish regions and work groups between January 2019 and September 2021. Abdominal volume index (AVI) and body adiposity index (BAI) were evaluated to assess obesity and its association with insulin resistance using three risk scales (TyG index, Triglycerides/HDL, and METS-IR), while their association with metabolic syndrome was determined using the NCEP ATP III, IDF, and JIS models.

RESULTS

The results of the ROC curves to determine the predictive value of BAI and AVI in relation to the three criteria evaluated to calculate MetS in all instances presented a higher area under the curve (AUC) for AVI. The high values of AVI stand out for predicting MetS when applying the IDF criteria. The cut-off point in women was 13.70 with a Youden index of 0.802, whereas in men, the cut-off point was set at 17.59 with a Youden index of 0.672. Regarding the relationship of BAI and AVI with insulin resistance risk scales for both sexes, the AUC only revealed high values when using the METS-IR formula for both AVI and BAI. The AVI cut-off points to predict high values of insulin resistance risk scales in women were established at 13.12 with a Youden index of 0.722. In men, the cut-off point was 17.59, with a Youden index of 0.626. The BAI cut-off points in women were set at 33.88 with a Youden index of 0.748. In men, the cut-off point was 27.91, with a Youden index of 0.598.

CONCLUSIONS

AVI demonstrated its value as a predictor of metabolic syndrome while exclusively applying the IDF criteria. AVI and BAI demonstrated their value as predictors of high values of insulin resistance risk scales only in the case of METS-IR. This predictive value is also higher in women.

Mechanisms of Qingyi Decoction in Severe Acute Pancreatitis-Associated Acute Lung Injury via Gut Microbiota: Targeting the Short-Chain Fatty Acids-Mediated AMPK/NF-κB/NLRP3 Pathway

The pivotal roles of gut microbiota in severe acute pancreatitis-associated acute lung injury (SAP-ALI) are increasingly revealed, and recent discoveries in the gut-lung axis have provided potential approaches for treating SAP-ALI. Qingyi decoction (QYD), a traditional Chinese medicine (TCM), is commonly used in clinical to treat SAP-ALI. However, the underlying mechanisms remain to be fully elucidated. Herein, by using a caerulein plus lipopolysaccharide (LPS)-induced SAP-ALI mice model and antibiotics (Abx) cocktail-induced pseudogermfree mice model, we tried to uncover the roles of the gut microbiota by administration of QYD and explored its possible mechanisms. Immunohistochemical results showed that the severity of SAP-ALI and intestinal barrier functions could be affected by the relative depletion of intestinal bacteria. The composition of gut microbiota was partially recovered after QYD treatment with decreased Firmicutes/Bacteroidetes ratio and increased relative abundance in short-chain fatty acids (SCFAs)-producing bacteria. Correspondingly increased levels of SCFAs (especially propionate and butyrate) in feces, gut, serum, and lungs were observed, generally consistent with changes in microbes. Western-blot analysis and RT-qPCR results indicated that the AMPK/NF-κB/NLRP3 signaling pathway was activated after oral administration of QYD, which was found to be possibly related to the regulatory effects on SCFAs in the intestine and lungs. In conclusion, our study provides new insights into treating SAP-ALI through modulating the gut microbiota and has prospective practical value for clinical use in the future. IMPORTANCE Gut microbiota affects the severity of SAP-ALI and intestinal barrier function. During SAP, a significant increase in the relative abundance of gut pathogens (Escherichia, Enterococcus, Enterobacter, Peptostreptococcus, Helicobacter) was observed. At the same time, QYD treatment decreased pathogenic bacteria and increased the relative abundance of SCFAs-producing bacteria (Bacteroides, Roseburia, Parabacteroides, Prevotella, Akkermansia). In addition, The AMPK/NF-κB/NLRP3 pathway mediated by SCFAs along the gut-lung axis may play an essential role in preventing the pathogenesis of SAP-ALI, which allows for reduced systemic inflammation and restoration of the intestinal barrier.

Targeting metabolic pathways: a novel therapeutic direction for type 2 diabetes

Background

Type 2 diabetes mellitus (T2DM) is a prevalent metabolic disease that causes multi-organ complications, seriously affecting patients' quality of life and survival. Understanding its pathogenesis remains challenging, with current clinical treatment regimens often proving ineffective.

Methods

In this study, we established a mouse model of T2DM and employed 16s rDNA sequencing to detect changes in the species and structure of gut flora. Additionally, we used UPLC-Q-TOF-MS to identify changes in urinary metabolites of T2DM mice, analyzed differential metabolites and constructed differential metabolic pathways. Finally, we used Pearman correlation analysis to investigate the relationship between intestinal flora and differential metabolites in T2DM mice, aiming to elucidate the pathogenesis of T2DM and provide an experimental basis for its clinical treatment.

Results

Our findings revealed a reduction in both the species diversity and abundance of intestinal flora in T2DM mice, with significantly decreased levels of beneficial bacteria such as Lactobacillus and significantly increased levels of harmful bacteria such as Helicobacter pylori. Urinary metabolomics results identified 31 differential metabolites between T2DM and control mice, including Phosphatidylcholine, CDP-ethanolamine and Leukotriene A4, which may be closely associated with the glycerophospholipid and arachidonic acid pathways. Pearman correlation analysis showed a strong correlation between dopamine and gonadal, estradiol and gut microbiota, may be a novel direction underlying T2DM.

Conclusion

In conclusion, our study suggests that alterations in gut microbiota and urinary metabolites are characteristic features of T2DM in mice. Furthermore, a strong correlation between dopamine, estradiol and gut microbiota, may be a novel direction underlying T2DM, the aim is to provide new ideas for clinical treatment and basic research.

The gut microbiota-astrocyte axis: Implications for type 2 diabetic cognitive dysfunction

BACKGROUND

Diabetic cognitive dysfunction (DCD) is one of the most insidious complications of type 2 diabetes mellitus, which can seriously affect the ability to self-monitoring of blood glucose and the quality of life in the elderly. Previous pathological studies of cognitive dysfunction have focused on neuronal dysfunction, characterized by extracellular beta-amyloid deposition and intracellular tau hyperphosphorylation. In recent years, astrocytes have been recognized as a potential therapeutic target for cognitive dysfunction and important participants in the central control of metabolism. The disorder of gut microbiota and their metabolites have been linked to a series of metabolic diseases such as diabetes mellitus. The imbalance of intestinal flora has the effect of promoting the occurrence and deterioration of several diabetes-related complications. Gut microbes and their metabolites can drive astrocyte activation.

AIMS

We reviewed the pathological progress of DCD related to the "gut microbiota-astrocyte" axis in terms of peripheral and central inflammation, intestinal and blood-brain barrier (BBB) dysfunction, systemic and brain energy metabolism disorders to deepen the pathological research progress of DCD and explore the potential therapeutic targets.

CONCLUSION

"Gut microbiota-astrocyte" axis, unique bidirectional crosstalk in the brain-gut axis, mediates the intermediate pathological process of neurocognitive dysfunction secondary to metabolic disorders in diabetes mellitus.

Galanin ameliorates liver inflammation and fibrosis in mice by activating AMPK/ACC signaling and modifying macrophage inflammatory phenotype

Background and aims

Galanin is a naturally occurring peptide that plays a critical role in regulating inflammation and energy metabolism, with expression in the liver. The exact involvement of galanin in non-alcoholic fatty liver disease and related fibrosis remains controversial.

Methods

The effects of subcutaneously administered galanin were studied in mice with non-alcoholic steatohepatitis (NASH) induced by a high-fat and high-cholesterol diet for 8 weeks, and in mice with liver fibrosis induced by CCl4 for 7 weeks. The underlying mechanism was also studied in vitro on murine macrophage cells (J774A.1 and RAW264.7).

Results

Galanin reduced inflammation, CD68-positive cell count, MCP-1 level, and mRNA levels of inflammation-related genes in the liver of NASH mice. It also mitigated liver injury and fibrosis caused by CCl4. In vitro, galanin had anti-inflammatory effects on murine macrophages, including reduced phagocytosis and intracellular reactive oxygen species (ROS). Galanin also activated AMP-activated protein kinase (AMPK)/acetyl-CoA carboxylase (ACC) signaling.

Conclusion

Galanin ameliorates liver inflammation and fibrosis in mice, potentially by modifying macrophage inflammatory phenotype and activating AMPK/ACC signaling.

Air Pollutant impacts on the brain and neuroendocrine system with implications for peripheral organs: a perspective

Air pollutants are being increasingly linked to extrapulmonary multi-organ effects. Specifically, recent studies associate air pollutants with brain disorders including psychiatric conditions, neuroinflammation and chronic diseases. Current evidence of the linkages between neuropsychiatric conditions and chronic peripheral immune and metabolic diseases provides insights on the potential role of the neuroendocrine system in mediating neural and systemic effects of inhaled pollutants (reactive particulates and gases). Autonomically-driven stress responses, involving sympathetic-adrenal-medullary and hypothalamus-pituitary-adrenal axes regulate cellular physiological processes through adrenal-derived hormones and diverse receptor systems. Recent experimental evidence demonstrates the contribution of the very stress system responding to non-chemical stressors, in mediating systemic and neural effects of reactive air pollutants. The assessment of how respiratory encounter of air pollutants induce lung and peripheral responses through brain and neuroendocrine system, and how the impairment of these stress pathways could be linked to chronic diseases will improve understanding of the causes of individual variations in susceptibility and the contribution of habituation/learning and resiliency. This review highlights effects of air pollution in the respiratory tract that impact the brain and neuroendocrine system, including the role of autonomic sensory nervous system in triggering neural stress response, the likely contribution of translocated nano particles or metal components, and biological mediators released systemically in causing effects remote to the respiratory tract. The perspective on the use of systems approaches that incorporate multiple chemical and non-chemical stressors, including environmental, physiological and psychosocial, with the assessment of interactive neural mechanisms and peripheral networks are emphasized.

Pectin mediates the mechanism of host blood glucose regulation through intestinal flora

Pectin is a complex polysaccharide found in plant cell walls and interlayers. As a food component, pectin is benefit for regulating intestinal flora. Metabolites of intestinal flora, including short-chain fatty acids (SCFAs), bile acids (BAs) and lipopolysaccharides (LPS), are involved in blood glucose regulation. SCFAs promote insulin synthesis through the intestine-GPCRs-derived pathway and hepatic adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK) pathway to promote hepatic glycogen synthesis. On the one hand, BAs stimulate intestinal L cells and pancreatic α cells to secrete Glucagon-like peptide-1 (GLP-1) and peptide YY (PYY) through receptors G protein-coupled receptor (TGR5) and farnesoid X receptor (FXR). On the other hand, BAs promote hepatic glycogen synthesis through AMPK pathway. LPS inhibits the release of inflammatory cytokines through Toll-like receptors (TLRs)-myeloid differentiation factor 88 (MYD88) pathway and mitogen-activated protein kinase (MAPK) pathway, thereby alleviating insulin resistance (IR). In brief, both SCFAs and BAs promote GLP-1 secretion through different pathways, employing strategies of increasing glucose consumption and decreasing glucose production to maintain normal glucose levels. Notably, pectin can also directly inhibit the release of inflammatory cytokines through the -TLRs-MYD88 pathway. These data provide valuable information for further elucidating the relationship between pectin-intestinal flora-glucose metabolism.

Effects of several flavonoids on human gut microbiota and its metabolism by in vitro simulated fermentation

Introduction

Flavonoids have antiviral, antitumor, anti-inflammatory, and other biological activities. They have high market value and are widely used in food and medicine fields. They also can regulate gut microbiota and promote human health. However, only a few flavonoids have been reported for their regulatory effects on human gut microbiota.

Methods

The effects of hesperidin, hesperetin-7-O-glucoside, hesperetin, naringin, prunin, naringenin, rutin, isoquercitrin, and quercetin on gut microbiota structural and metabolic differences in healthy subjects were studied by means of in vitro simulated fermentation technology.

Results

Results showed that the nine kinds of flavonoids mentioned above, especially hesperetin-7-O-glucoside, prunin, and isoquercitrin, were found to have more effect on the structure of human gut microbiota, and they could significantly enhance Bifidobacterium (p < 0.05). After 24 h of in vitro simulated fermentation, the relative abundance of intestinal probiotics (e.g., Lactobacillus) was increased by the three flavonoids and rutin. Furthermore, the relative abundance of potential pathogenic bacteria was decreased by the addition of hesperetin-7-O-glucoside, naringin, prunin, rutin, and isoquercitrin (e.g., Lachnoclostridium and Bilophila). Notably, prunin could also markedly decrease the content of H₂S, NH₃, and short-chain fatty acids. This performance fully demonstrated its broad-spectrum antibacterial activity.

Discussion

This study demonstrates that flavonoids can regulate the imbalance of gut microbiota, and some differences in the regulatory effect are observed due to different structures. This work provides a theoretical basis for the wide application of flavonoids for food and medicine.

Bear bile powder ameliorates type 2 diabetes via modulation of metabolic profiles, gut microbiota, and metabolites

Introduction: Bear bile powder (BBP) is widely used in the clinic and has a hypoglycemic effect, but its mechanism is not clear. Methods: In this study, type 2 diabetes mellitus (T2DM) rats induced by a high-sugar and high-fat diet combined with streptozotocin were given BBP, and biochemical indexes, pathological sections, metabonomics, intestinal microbiota (IM) and short-chain fatty acids (SCFAs) were determined. Results: The results showed that BBP could reduce blood glucose, relieve inflammation, insulin resistance, and lipid metabolism disorder, and alleviate tissue damage of the liver, spleen, kidney, and pancreas in T2DM rats. It is worth noting that BBP can reverse the changes in blood and urine metabolites in T2DM rats, which are mainly related to tryptophan metabolism, pentose and glucuronate interconversions, starch and sucrose metabolism, and glycerophospholipid metabolism. In addition, BBP restored IM disorder in T2DM rats, decreased the abundance of Allobaculum, Blautia, Dubosiella, and Anaerostipes, enriched the abundance of Lactobacillus, Romboutsia, UCG-005, and norank_f__Eggerthellaceae, and increased the concentration of SCFAs in intestinal contents. Discussion: These findings suggest that BBP may improve T2DM by regulating multiple metabolic pathways, IM composition, and SCFAs levels.

Short-Chain Fatty Acids as Bacterial Enterocytes and Therapeutic Target in Diabetes Mellitus Type 2

Diabetes mellitus is a disease with multiple gastrointestinal symptoms (diarrhea or constipation, abdominal pain, bloating) whose pathogenesis is multifactorial. The most important of these factors is the enteric nervous system, also known as the "second brain"; a part of the peripheral nervous system capable of functioning independently of the central nervous system. Modulation of the enteric nervous system can be done by short-chain fatty acids, which are bacterial metabolites of the intestinal microbiota. In addition, these acids provide multiple benefits in diabetes, particularly by stimulating glucagon-like peptide 1 and insulin secretion. However, it is not clear what type of nutraceuticals (probiotics, prebiotics, and alimentary supplements) can be used to increase the amount of short-chain fatty acids and achieve the beneficial effects in diabetes. Thus, even if several studies demonstrate that the gut microbiota modulates the activity of the ENS, and thus, may have a positive effect in diabetes, further studies are needed to underline this effect. This review outlines the most recent data regarding the involvement of SCFAs as a disease modifying agent in diabetes mellitus type 2. For an in-depth understanding of the modulation of gut dysbiosis with SCFAs in diabetes, we provide an overview of the interplay between gut microbiota and ENS.

Enoxacin ameliorates polycystic ovary syndrome by promoting the browning of white adipose tissue and restoring gut dysbiosis

Polycystic ovary syndrome (PCOS) is a complex endocrine disorder syndrome characterized by polycystic ovary, ovulation disorder and hyperandrogenemia, and is often accompanied by metabolic disorders. Enoxacin has been reported to protect against diet-induced obesity and insulin resistance by promoting fat thermogenesis. However, the function of enoxacin in PCOS remains unknown. This study aimed to investigate the impact of the enoxacin on the regulation of PCOS mouse model induced by dehydroepiandrosterone (DHEA). Here, we found that reproductive endocrine disorder, glucose intolerance, and ovarian dysfunction in PCOS mice induced by DHEA were attenuated by enoxacin treatment. Mechanistically, we identified that enoxacin can promote white fat browning and improve metabolic disorders, thus ameliorating DHEA-induced reproductive dysfunction. Moreover, these beneficial effects might be associated with the restoration of gut dysbiosis. These findings provide a novel therapeutic target for enoxacin in the treatment of PCOS.

Neuropsychiatric lupus erythematosus: Focusing on autoantibodies

Patients with systemic lupus erythematosus (SLE) frequently suffer from nervous system complications, termed neuropsychiatric lupus erythematosus (NPLE). NPLE accounts for the poor prognosis of SLE. Correct attribution of NP events to SLE is the primary principle in managing NPLE. The vascular injuries and neuroinflammation are the fundamental neuropathologic changes in NPLE. Specific autoantibody-mediated central nerve system (CNS) damages distinguish NPLE from other CNS disorders. Though the central antibodies in NPLE are generally thought to be raised from the periphery immune system, they may be produced in the meninges and choroid plexus. On this basis, abnormal activation of microglia and disease-associated microglia (DAM) should be the common mechanisms of NPLE and other CNS disturbances. Improved understanding of both characteristic and sharing features of NPLE might yield further options for managing this disease.