Sodium Butyrate Attenuates AGEs-Induced Oxidative Stress and Inflammation by Inhibiting Autophagy and Affecting Cellular Metabolism in THP-1 Cells

The Link between Salivary Amylase Activity, Overweight, and Glucose Homeostasis

Butyrate, a short-chain fatty acid (SCFA) produced by the fermentation of dietary fibers in the colon, plays a pivotal role in regulating metabolic health, particularly by enhancing insulin sensitivity. Given the rising incidence of metabolic disorders, understanding the factors that influence butyrate production is of significant interest. This study explores the link between salivary amylase activity and butyrate levels in overweight women of reproductive age. Participants were categorized into low (LSA) and high (HSA) salivary amylase activity groups and further divided into two subgroups: one followed a low-starch diet (LS), and the other underwent caloric restriction (CR). We assessed salivary amylase activity and measured serum butyrate concentrations to examine their associations. Our findings showed a significant, though weak, positive correlation (ρ = 0.0486, p < 0.05), suggesting a link between salivary amylase activity and butyrate levels. The statistical significance, despite the weak correlation, implies that this relationship is not random. Moreover, higher baseline butyrate levels were observed in women with elevated salivary amylase activity. Also, women with low salivary amylase activity on a low-starch diet experienced a more pronounced increase in butyrate levels compared to those on caloric restriction. These results suggest that salivary amylase activity and dietary intake interact to influence butyrate production, with potential implications for improving insulin sensitivity and metabolic health. The study underscores the potential of butyrate in enhancing insulin sensitivity and promoting overall metabolic well-being. Further research is necessary to clarify the mechanisms involved and to understand the long-term effects of butyrate on metabolic health across different populations.

Causal effect of gut microbiota and diabetic nephropathy: a Mendelian randomization study

BACKGROUND

The interaction of dysbiosis of gut microbiota (GM) with diabetic nephropathy (DN) drew our attention and a better understanding of GM on DN might provide potential therapeutic approaches. However, the exact causal effect of GM on DN remains unknown.

METHODS

We applied two-sample Mendelian Randomization (MR) analysis, including inverse variance weighted (IVW), MR-Egger methods, etc., to screen the significant bacterial taxa based on the GWAS data. Sensitivity analysis was conducted to assess the robustness of MR results. To identify the most critical factor on DN, Mendelian randomization-Bayesian model averaging (MR-BMA) method was utilized. Then, whether the reverse causality existed was verified by reverse MR analysis. Finally, transcriptome MR analysis was performed to investigate the possible mechanism of GM on DN.

RESULTS

At locus-wide significance levels, the results of IVW suggested that order Bacteroidales (odds ratio (OR) = 1.412, 95% confidence interval (CI): 1.025-1.945, P = 0.035), genus Akkermansia (OR = 1.449, 95% CI: 1.120-1.875, P = 0.005), genus Coprococcus 1 (OR = 1.328, 95% CI: 1.066-1.793, P = 0.015), genus Marvinbryantia (OR = 1.353, 95% CI: 1.037-1.777, P = 0.030) and genus Parasutterella (OR = 1.276, 95% CI: 1.022-1.593, P = 0.032) were risk factors for DN. Reversely, genus Eubacterium ventriosum (OR = 0.756, 95% CI: 0.594-0.963, P = 0.023), genus Ruminococcus gauvreauii (OR = 0.663, 95% CI: 0.506-0.870, P = 0.003) and genus Erysipelotrichaceae (UCG003) (OR = 0.801, 95% CI: 0.644-0.997, P = 0.047) were negatively associated with the risk of DN. Among these taxa, genus Ruminococcus gauvreauii played a crucial role in DN. No significant heterogeneity or pleiotropy in the MR result was found. Mapped genes (FDR < 0.05) related to GM had causal effects on DN, while FCGR2B and VNN2 might be potential therapeutic targets.

CONCLUSIONS

This work provided new evidence for the causal effect of GM on DN occurrence and potential biomarkers for DN. The significant bacterial taxa in our study provided new insights for the 'gut-kidney' axis, as well as unconventional prevention and treatment strategies for DN.

The effects of advanced glycation end-products on skin and potential anti-glycation strategies

The advanced glycation end-products (AGEs) are produced through non-enzymatic glycation between reducing sugars and free amino groups, such as proteins, lipids or nucleic acids. AGEs can enter the body through daily dietary intake and can also be generated internally via normal metabolism and external stimuli. AGEs bind to cell surface receptors for AGEs, triggering oxidative stress and inflammation responses that lead to skin ageing and various diseases. Evidence shows that AGEs contribute to skin dysfunction and ageing. This review introduces the basic information, the sources, the metabolism and absorption of AGEs. We also summarise the detrimental mechanisms of AGEs to skin ageing and other chronic diseases. For the potential strategies for counteracting AGEs to skin and other organs, we summarised the pathways that could be utilised to resist glycation. Chemical and natural-derived anti-glycation approaches are overviewed. This work offers an understanding of AGEs to skin ageing and other chronic diseases and may provide perspectives for the development of anti-glycation strategies.

Lung cancer progression alters lung and gut microbiomes and lipid metabolism

Despite advances in medical technology, lung cancer still has one of the highest mortality rates among all malignancies. Therefore, efforts must be made to understand the precise mechanisms underlying lung cancer development. In this study, we conducted lung and gut microbiome analyses and a comprehensive lipid metabolome analysis of host tissues to assess their correlation. Alternations in the lung microbiome due to lung cancer, such as a significantly decreased abundance of Firmicutes and Deferribacterota, were observed compared to a mock group. However, mice with lung cancer had significantly lower relative abundances of Actinobacteria and Proteobacteria and higher relative abundances of Cyanobacteria and Patescibacteria in the gut microbiome. The activations of retinol, fatty acid metabolism, and linoleic acid metabolism metabolic pathways in the lung and gut microbiomes was inversely correlated. Additionally, changes occurred in lipid metabolites not only in the lungs but also in the blood, small intestine, and colon. Compared to the mock group, mice with lung cancer showed that the levels of adrenic, palmitic, stearic, and oleic (a ω-9 polyunsaturated fatty acid) acids increased in the lungs. Conversely, these metabolites consistently decreased in the blood (serum) and colon. Leukotriene B4 and prostaglandin E2 exacerbate lung cancer, and were upregulated in the lungs of the mice with lung cancer. However, isohumulone, a peroxisome proliferator-activated receptor gamma activator, and resolvin (an ω-3 polyunsaturated fatty acid) both have anti-cancer effects, and were upregulated in the small intestine and colon. Our multi-omics data revealed that shifts in the microbiome and metabolome occur during the development of lung cancer and are of possible clinical importance. These results reveal one of the gut-lung axis mechanisms related to lung cancer and provide insights into potential new targets for lung cancer treatment and prophylaxis.

Lactiplantibacillus plantarum NKK20 Increases Intestinal Butyrate Production and Inhibits Type 2 Diabetic Kidney Injury through PI3K/Akt Pathway

Nephropathy injury is a prevalent complication observed in individuals with diabetes, serving as a prominent contributor to end-stage renal disease, and the advanced glycation products (AGEs) are important factors that induce kidney injury in patients with diabetes. Addressing this condition remains a challenging aspect in clinical practice. The aim of this study was to explore the effects of Lactiplantibacillus plantarum NKK20 strain (NKK20) which protects against diabetic kidney disease (DKD) based on animal and cell models. The results showed that the NKK20 can significantly reduce renal inflammatory response, serum oxidative stress response, and AGE concentration in diabetic mice. After treatment with NKK20, the kidney damage of diabetic mice was significantly improved, and more importantly, the concentration of butyrate, a specific anti-inflammatory metabolite of intestinal flora in the stool of diabetic mice, was significantly increased. In addition, nontargeted metabolomics analysis showed a significant difference between the metabolites in the mouse serum contents of the NKK20 administration group and those in the nephropathy injury group, in which a total of 24 different metabolites that were significantly affected by NKK20 were observed, and these metabolites were mainly involved in glycerophospholipid metabolism and arachidonic acid metabolism. Also, the administration of butyrate to human kidney- (HK-) 2 cells that were stimulated by AGEs resulted in a significant upregulation of ZO-1, Occludin, and E-cadherin gene expressions and downregulation of α-SMA gene expression. This means that butyrate can maintain the tight junction structure of HK-2 cells and inhibit fibrosis. Butyrate also significantly inhibited the activation of PI3K/Akt pathway. These results indicate that NKK20 can treat kidney injury in diabetic mice by reducing blood glucose and AGE concentration and increasing butyrate production in the intestine. By inhibiting PI3K pathway activation in HK-2 cells, butyrate maintains a tight junction structure of renal tubule epithelial cells and inhibits renal tissue fibrosis. These results suggest that NKK20 is helpful to prevent and treat the occurrence and aggravation of diabetic kidney injury.

Identification of Fibrotic Biomarkers Associated with Macrophages in Diabetic Nephropathy

BACKGROUND Diabetic nephropathy (DN) is the main cause of end-stage renal disease. Renal fibrosis is an important pathological feature of kidney injury, and the therapeutic means are very limited. The functions of macrophages play important roles in renal fibrosis. There is a complicated link between altered immune metabolism and oxidative stress. Hence, we designed this study to identify the oxidative stress- and macrophage-relevant biomarkers reflecting fibrosis in DN. MATERIAL AND METHODS Differential expression analysis was performed based on the GSE96804 dataset. xCell and weighted gene co-expression network analysis were used to determine the distinctions in infiltrating immune cells between DN and control specimens. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses were conducted. A protein-protein interaction network was constructed to identify the hub genes. Hub genes were validated in an external dataset, GSE30528, and cell models. RESULTS MMP2, CASP3, and HIF-1alpha were identified as biomarkers, which were upregulated in the DN group and positively correlated with the infiltration of macrophages and M1 macrophages. In vitro, the 3 genes were highly expressed in murine MPC5 cells treated with high glucose and human THP-1 macrophages treated with advanced glycation end products. CONCLUSIONS Our results provided biomarkers for predicting the fibrotic progression of DN and confirmed that MMP2, CAPS3, and HIF-1alpha have good diagnostic value. They might be involved in the progression of DN fibrosis by regulating oxidative stress and macrophage recruitment or polarization.

A Plantaginis Semen-Coptidis Rhizoma compound alleviates type 2 diabetic mellitus in mice via modulating AGEs-RAGE pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Plantaginis Semen-Coptidis Rhizoma Compound(CQC) was first recorded in Shengji Zonglu. Clinical and experimental studies have reported that both of Plantaginis Semen and Coptidis Rhizoma exerted the effects of lowering blood glocose and lipid. However, the potential mechanism of CQC on type 2 diabetes (T2DM) remain unclear.

AIM OF THE STUDY

The main objective of our investigation was to explore the mechanisms of CQC on T2DM based on network pharmacology and experimental research.

MATERIALS AND METHODS

Streptozotocin(STZ)/high fat diet(HFD)-induced T2DM models in mice were established to evaluate the antidiabetic effect of CQC in vivo. We obtained the chemical constituents of Plantago and Coptidis from the TCMSP database and literature sources. Potential targets of CQC were gleaned from the Swiss-Target-Prediction database, and T2DM targets were obtained from Drug-Bank, TTD, and DisGeNet. A protein-protein interaction (PPI) network was constructed in the String database. The David database was used for gene ontology (GO) and KEGG pathway enrichment analyses. We then verified the potential mechanism of CQC that were predicted by network pharmacological analysis in STZ/HFD-induced T2DM mouse model.

RESULTS

Our experiments confirmed that CQC improved hyperglycemia and liver injury. We identified 21 components and gleaned 177 targets for CQC treatment of T2DM. The core component-target network included 13 compounds and 66 targets. We further demonstrated that CQC improve T2DM through various pathways, especially the AGEs/RAGE signal pathway.

CONCLUSION

Our results indicated that CQC could improve the metabolic disorders of T2DM and it is a promising TCM compound for the treatment of T2DM. The potential mechanism may probably involve the regulation of the AGEs/RAGE signaling pathway.

Tributyrin Intake Attenuates Angiotensin II-Induced Abdominal Aortic Aneurysm in LDLR-/- Mice

Abdominal aortic aneurysm (AAA) is a multifactorial cardiovascular disease with a high risk of death, and it occurs in the infrarenal aorta with vascular dilatation. High blood pressure acts on the aortic wall, resulting in rupture and causing life-threatening intra-abdominal hemorrhage. Vascular smooth muscle cell (VSMC) dysregulation and extracellular matrix (ECM) degradation, especially elastin breaks, contribute to structural changes in the aortic wall. The pathogenesis of AAA includes the occurrence of oxidative stress, inflammatory cell infiltration, elastic fiber fragmentation, VSMC apoptosis, and phenotypic transformation. Tributyrin (TB) is decomposed by intestinal lipase and has a function similar to that of butyrate. Whether TB has a protective effect against AAA remains uncertain. In the present study, we established an AAA murine model by angiotensin II (AngII) induction in low-density lipoprotein receptor knockout (LDLR^-/-) mice and investigated the effects of orally administered TB on the AAA size, ratio of macrophage infiltration, levels of matrix metalloproteinase (MMP) expression, and epigenetic regulation. TB attenuates AngII-induced AAA size and decreases elastin fragmentation, macrophage infiltration, and MMP expression in the medial layer of the aorta and reduces the levels of SBP (systolic blood pressure, p < 0.001) and MMP-2 (p < 0.02) in the serum. TB reduces the AngII-stimulated expression levels of MMP2 (p < 0.05), MMP9 (p < 0.05), MMP12, and MMP14 in human aortic smooth muscle cells (HASMCs). Moreover, TB and valproic acid (VPA), a histone deacetylase (HDAC) inhibitor, suppress AngII receptor type 1 (AT1R, p < 0.05) activation and increase the expression of acetyl histone H3 by HDAC activity inhibition (p < 0.05). Our findings suggest that TB exerts its protective effect by suppressing the activation of HDAC to attenuate the AngII-induced AT1R signaling cascade.

Inflammation and Oxidative Stress in Frailty and Metabolic Syndromes-Two Sides of the Same Coin

In developed countries, aging is often seen as typical, but it is made complicated by many disorders and co-morbidities. Insulin resistance seems to be an underlying pathomechanism in frailty and metabolic syndromes. The decline in insulin sensitivity leads to changes in the oxidant-antioxidant balance and an accelerated inflammatory response, especially by adipocytes and macrophages in adipose tissue, as well as muscle mass density. Thus, in the pathophysiology of syndemic disorders-the metabolic syndrome and frailty syndrome-an extremely important role may be played by increased oxidative stress and pro-inflammatory state. Papers included in this review explored available full texts and the reference lists of relevant studies from the last 20 years, before the end of 2022; we also investigated the PubMed and Google Scholar electronic databases. The online resources describing an elderly population (≥65 years old) published as full texts were searched for the following terms: "oxidative stress and/or inflammation", "frailty and/or metabolic syndrome". Then, all resources were analyzed and narratively described in the context of oxidative stress and/or inflammation markers which underlie pathomechanisms of frailty and/or metabolic syndromes in elderly patients. So far, different metabolic pathways discussed in this review show that a similar pathogenesis underlies the development of the metabolic as well as frailty syndromes in the context of increased oxidative stress and acceleration of inflammation. Thus, we argue that the syndemia of the syndromes represents two sides of the same coin.