Analysis of jejunum microbiota of HFD/STZ diabetic rats

Distribution of gut microbiota across intestinal segments and their impact on human physiological and pathological processes

In recent years, advancements in metagenomics, metabolomics, and single-cell sequencing have enhanced our understanding of the intricate relationships between gut microbiota and their hosts. Gut microbiota colonize humans from birth, with their initial composition significantly influenced by the mode of delivery and feeding method. During the transition from infancy to early childhood, exposure to a diverse diet and the maturation of the immune system lead to the gradual stabilization of gut microbiota's composition and distribution. Numerous studies have demonstrated that gut microbiota can influence a wide range of physiological functions and pathological processes by interacting with various tissues and organs through the gut-organ axis. Different intestinal segments exhibit unique physical and chemical conditions, which leads to the formation of vertical gradients along the intestinal tract: aerobes and facultative aerobes mainly live in the small intestine and anaerobic bacteria mainly live in the large intestine, and horizontal gradients: mucosa-associated microbiota and lumen-associated microbiota. In this review, we systematically summarize the distribution characteristics of gut microbiota across six intestinal segments: duodenum, jejunum, ileum, cecum, colon, and rectum. We also draw a conclusion that gut microbiota distributed in different intestinal segments affect the progression of different diseases. We hope to elucidate the role of microbiota at specific anatomic sites within the gut in precisely regulating the processes of particular diseases, thereby providing a solid foundation for developing novel diagnostic and therapeutic strategies for related diseases.

The acetylation of Ganoderma applanatum polysaccharides on ameliorating T2DM-induced hepatic and colonic injuries by modulating the Nrf2/keap1-TLR4/NFκB-Bax/Bcl-2 pathways

It was imperative to discover and utilize high-efficiency, non-toxic substances for the prevention and management of type 2 diabetes mellitus (T2DM) and its associated complications, given the escalating prevalence and significant global health burden. In the present study, the acetylated Ganoderma applanatum polysaccharide (A-GAP) was successfully obtained and characterized, demonstrating excellent efficacy in ameliorating organ damage induced by T2DM through targeted modulation of the gut-liver axis. The physiological and molecular biological findings indicated that A-GAP may modulate the Nrf2/Keap1-TLR4/NFκB-Bax/Bcl-2 signaling pathway network, thereby mitigating oxidative stress and the subsequent inflammatory response, ultimately alleviating the inhibitory effects of IRS and insulin resistance. Besides, the regulatory impact of A-GAP on the gut-liver axis had been confirmed by its ability to maintain intestinal barrier integrity and increase levels of intestinal tight junction proteins, effectively preventing endotoxin translocation to the liver. This discovery highlighted the potential of A-GAP as a promising option for functional or nutritional foods and pharmaceuticals in managing T2DM and its complications, showcasing the significance of acetylation in enhancing the bioactivities of natural substances.

Trichosanthes kirilowii Maxim. Polysaccharide attenuates diabetes through the synergistic impact of lipid metabolism and modulating gut microbiota

Polysaccharide, a chain of sugars bound by glycosidic bonds, have a wide range of physiological activities, including hypoglycemic activity. In present study, we established T2DM mice models to explore the effects and mechanism of Trichosanthes kirilowii Maxim polysaccharide (TMSP1) on high-fat diet/streptozotocin (HF-STZ) induced diabetes mice. The results showed that high-fat diet significantly increased the oral glucose tolerance test (OGTT), viscera index, oxidative stress, impaired glucose tolerance, decreased body weight, immune response and short-chain fatty acid (SCFAs) content, and disrupted the balance of intestinal flora structure. However, after 6 weeks of TMSP1 intervention decreased lipid accumulation, ameliorated gut microbiota dysbiosis by increasing SCFAs-producing bacteria and mitigated intestinal inflammation and oxidative stress. Moreover, TMSP1 significantly restored the integrity of the intestinal epithelial barrier and mucus barrier. The results of fecal microbiota transplantation confirmed that TMSP1 exerted hypoglycemic effect through regulating intestinal flora to a certain extent. Collectively, the findings revealed TMSP1 intervention inhibits hyperglycemia by improving gut microbiota disorder, lipid metabolism, and inflammation. Hence, TMSP1 may be an effective measure to ameliorate HF-STZ induced diabetes.

Enteromorpha prolifera polysaccharide-Fe (III) complex promotes intestinal development as a new iron supplement

Iron is a crucial micronutrient, and its deficiency can have detrimental effects on the health of infants. Dietary polysaccharide-iron (III) complexes (PICs) are promising for addressing iron deficiency due to their minimal adverse reactions and high iron absorption rate. This study aimed to investigate the effects of dietary Enteromorpha prolifera polysaccharide-Fe (III) complex (EP-Fe) on newborns, using 3-day weaned piglets as the iron-deficiency model. Results showed that EP-Fe improved iron levels and promoted intestinal development in piglets. Transcriptome sequencing revealed that EP-Fe increased the survival of intestinal epithelial cells under hypoxia by upregulating the expression of genes that promote the development of the vascular system. Additionally, EP-Fe enhanced the mucosal barrier functions by inhibiting myosin light chain kinase (MLCK)/phosphorylated myosin light chain (p-MLC) signaling pathway to increase the expression of intestinal tight junction proteins. Furthermore, the 16S rRNA gene sequencing of gut microbiota showed that EP-Fe promoted the enrichment of Bacteroides_fragilis and other gut microbes that can metabolize carbohydrates. In conclusion, EP-Fe is an effective iron supplement for newborns, and it can be developed as a comprehensive nutritional supplement.

Bile acids as a key target: traditional Chinese medicine for precision management of insulin resistance in type 2 diabetes mellitus through the gut microbiota-bile acids axis

Type 2 diabetes mellitus (T2DM) is a chronic metabolic disease caused by insulin resistance (IR) and insufficient insulin secretion. Its characteristic pathophysiological processes involve the interaction of multiple mechanisms. In recent years, globally, the prevalence of T2DM has shown a sharp rise due to profound changes in socio-economic structure, the persistent influence of environmental factors, and the complex role of genetic background. It is worth noting that most T2DM patients show significant IR, which further exacerbates the difficulty of disease progression and prevention. In the process of extensively exploring the pathogenesis of T2DM, the dynamic equilibrium of gut microbes and its diverse metabolic activities have increasingly emphasized its central role in the pathophysiological process of T2DM. Bile acids (BAs) metabolism, as a crucial link between gut microbes and the development of T2DM, not only precisely regulates lipid absorption and metabolism but also profoundly influences glucose homeostasis and energy balance through intricate signaling pathways, thus playing a pivotal role in IR progression in T2DM. This review aims to delve into the specific mechanism through which BAs contribute to the development of IR in T2DM, especially emphasizing how gut microbes mediate the metabolic transformation of BAs based on current traditional Chinese medicine research. Ultimately, it seeks to offer new insights into the prevention and treatment of T2DM. Diet, genetics, and the environment intricately sculpt the gut microbiota and BAs metabolism, influencing T2DM-IR. The research has illuminated the significant impact of single herbal medicine, TCM formulae, and external therapeutic methods such as electroacupuncture on the BAs pool through perturbations in gut microbiota structure. This interaction affects glucose and lipid metabolism as well as insulin sensitivity. Additionally, multiple pathways including BA-FXR-SHP, BA-FXR-FGFR15/19, BA-FXR-NLRP3, BA-TGR5-GLP-1, BAs-TGR5/FXR signaling pathways have been identified through which the BAs pool significantly alter blood glucose levels and improve IR. These findings offer novel approaches for enhancing IR and managing metabolic disorders among patients with T2DM.

Er-Dong-Xiao-Ke decoction regulates lipid metabolism via PPARG-mediated UCP2/AMPK signaling to alleviate diabetic meibomian gland dysfunction

ETHNOPHARMACOLOGICAL RELEVANCE

Meibomian gland dysfunction (MGD), complicated by type 2 diabetes, is associated with a high incidence of ocular surface disease, and no effective drug treatment exists. Diabetes mellitus (DM) MGD shows a notable disturbance in lipid metabolism. Er-Dong-Xiao-Ke decoction (EDXKD) has important functions in nourishing yin, clearing heat, and removing blood stasis, which are effective in the treatment of DM MGD.

AIM OF THE STUDY

To observe the therapeutic effect of EDXKD on DM MGD and its underlying molecular mechanism.

MATERIALS AND METHODS

After establishing a type 2 DM (T2DM)-induced MGD rat model, different doses of EDXKD and T0070907 were administered. The chemical constituents of EDXKD were identified by liquid chromatography-tandem mass spectrometry (LC-MS/MS), and the molecular mechanism of EDXKD in treating DM MGD was predicted using network pharmacology. Lipid metabolism in DM meibomian glands (MGs) was analyzed using LC-MS/MS, and lipid biomarkers were screened and identified. Histological changes and lipid accumulation in MGs were detected by staining, and Peroxisome proliferator-activated receptor gamma (PPARG) expression in MG acinar cells was detected by immunofluorescence. The expression of lipid metabolism-related factors was detected by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) or western blotting.

RESULTS

EDXKD reduced lipid accumulation in the MGs and improved the ocular surface index in DM MGD rats. The main active components of EDXKD had advantages in lipid regulation. Additionally, the PPARG signaling pathway was the key pathway of EDXKD in the treatment of DM MGD. Twelve lipid metabolites were biomarkers of EDXKD in the treatment of DM MGD, and glycerophospholipid metabolism was the main pathway of lipid regulation. Moreover, EDXKD improved lipid deposition in the acini and upregulated the expression of PPARG. Further, EDXKD regulated the PPARG-mediated UCP2/AMPK signaling network, inhibited lipid production, and promoted lipid transport.

CONCLUSION

EDXKD is an effective treatment for MGD in patients with T2DM. EDXKD can regulate lipids by regulating the PPARG-mediated UCP2/AMPK signaling network, as it reduced lipid accumulation in the MGs of DM MGD rats, promoted lipid metabolism, and improved MG function and ocular surface indices.

The impact of gut microbial dysbiosis on the atrophy of the hippocampus and abnormal metabolism of N-acetyl aspartate in type 2 diabetic rats

Rationale and objectives

This study aimed to investigate the effect of intestinal dysbiosis on the hippocampal volume using proton magnetic resonance spectroscopy (1H-MRS) in a type 2 diabetes mellitus (T2DM) rat model.

Materials and methods

We established a T2DM animal model with high-fat diet and streptozotocin (HFD/STZ) administration to Sprague-Dawley rats. Short-term ceftriaxone sodium administration was used to establish a T2DM intestinal dysbiosis (T2DM-ID) model. After establishing the model, fecal microbiota were detected using 16S rRNA sequencing. The models were then subjected to magnetic resonance imaging (MRI). Associations between MRI findings and fecal microbiota were evaluated.

Results

Magnetic resonance imaging (MRI) showed that the bilateral hippocampal voxel value and N-acetylaspartate (NAA) level were lower in the experimental group than in the normal control (NC) group (p < 0.05) and that NAA/creatine in the left hippocampus was lower in the T2DM-ID group than in the NC group (p < 0.05). α and β diversities differed significantly among the three groups (p < 0.05). In the T2DM and T2DM-ID groups, the abundance of bacteria in the phylum Proteobacteria increased significantly, whereas that of bacteria in the phylum Firmicutes decreased. The relative abundance of Actinobacteria was significantly increased in the T2DM-ID group. The Chao1 index (r = 0.33, p < 0.05) and relative abundance of Firmicutes (r = 0.48, p < 0.05) were positively correlated with the left hippocampal voxel, while the relative abundance of Proteobacteria was negatively correlated with the left hippocampal voxel (r = -0.44, p < 0.05). NAA levels, bilateral hippocampal voxels, and the relative abundance of Lactobacillus, Clostridia_UCG_014, and other genera were correlated positively (r = 0.34-0.70, p < 0.05). NAA levels and the relative abundances of Blautia and Enterococcus were correlated negatively (r = -0.32-0.44, p < 0.05).

Conclusion

The T2DM-ID rat model showed hippocampal volume atrophy and decreased levels of neuronal markers (such as NAA). The abnormal content of specific gut microorganisms may be a key biomarker of T2DM-associated brain damage.

Common dietary emulsifiers promote metabolic disorders and intestinal microbiota dysbiosis in mice

Dietary emulsifiers are linked to various diseases. The recent discovery of the role of gut microbiota-host interactions on health and disease warrants the safety reassessment of dietary emulsifiers through the lens of gut microbiota. Lecithin, sucrose fatty acid esters, carboxymethylcellulose (CMC), and mono- and diglycerides (MDG) emulsifiers are common dietary emulsifiers with high exposure levels in the population. This study demonstrates that sucrose fatty acid esters and carboxymethylcellulose induce hyperglycemia and hyperinsulinemia in a mouse model. Lecithin, sucrose fatty acid esters, and CMC disrupt glucose homeostasis in the in vitro insulin-resistance model. MDG impairs circulating lipid and glucose metabolism. All emulsifiers change the intestinal microbiota diversity and induce gut microbiota dysbiosis. Lecithin, sucrose fatty acid esters, and CMC do not impact mucus-bacterial interactions, whereas MDG tends to cause bacterial encroachment into the inner mucus layer and enhance inflammation potential by raising circulating lipopolysaccharide. Our findings demonstrate the safety concerns associated with using dietary emulsifiers, suggesting that they could lead to metabolic syndromes.

Investigation of anti-diabetic effect of a novel coenzyme Q10 derivative

Introduction: The rising incidence of type 2 diabetes has seriously affected international public health. The search for more drugs that can effectively treat diabetes has become a cutting-edge trend in research. Coenzyme Q10 (CoQ10) has attracted much attention in the last decade due to its wide range of biological activities. Many researchers have explored the clinical effects of CoQ10 in patients with type 2 diabetes. However, CoQ10 has low bio-availability due to its high lipophilicity. Therefore, we have structurally optimized CoQ10 in an attempt to exploit the potential of its pharmacological activity. Methods: A novel coenzyme Q10 derivative (L-50) was designed and synthesized by introducing a group containing bromine atom and hydroxyl at the terminal of coenzyme Q10 (CoQ10), and the antidiabetic effect of L-50 was investigated by cellular assays and animal experiments. Results: Cytotoxicity results showed that L-50 was comparatively low toxicity to HepG2 cells. Hypoglycemic assays indicated that L-50 could increase glucose uptake in IR-HepG2 cells, with significantly enhanced hypoglycemic capacity compared to the CoQ10. In addition, L-50 improved cellular utilization of glucose through reduction of reactive oxygen species (ROS) accumulated in insulin-resistant HepG2 cells (IR-HepG2) and regulation of JNK/AKT/GSK3β signaling pathway, resulting in hypoglycemic effects. Furthermore, the animal experiments demonstrated that L-50 could restore the body weight of HFD/STZ mice. Notably, the findings suggested that L-50 could improve glycemic and lipid metabolism in HFD/STZ mice. Moreover, L-50 could increase fasting insulin levels (FINS) in HFD/STZ mice, leading to a decrease in fasting blood glucose (FBG) and hepatic glycogen. Furthermore, L-50 could recover triglycerides (TG), total cholesterol (T-CHO), lipoprotein (LDL-C) and high-density lipoprotein (HDL-C) levels in HFD/STZ mice. Discussion: The addition of a bromine atom and a hydroxyl group to CoQ10 could enhance its anti-diabetic activity. It is anticipated that L-50 could be a promising new agent for T2DM.

Structural characterization of Hericium erinaceus polysaccharides and the mechanism of anti-T2DM by modulating the gut microbiota and metabolites

A low molecular weight polysaccharides of HEP-1, with molecular weights of 1.67 × 10⁴ Da and composition of →6)-β-D-Glcp-(1→, →3)-β-D-Glcp-(1→, β-D-Glcp-(1→ and →3,6)-β-D-Glcp-(1→, was isolated and characterized from the fruiting body of Hericium erinaceus. The results indicated that HEP-1 showed potential effects against T2DM-induced imbalance of glucose and lipid metabolism by promoting the serum glucose uptake by hepatic glycogen synthesis via activating the IRS/PI3K/AKT signaling pathway, and inhibiting fatty acid synthesis and reducing hepatic lipid accumulation via activating the AMPK/SREBP-1c signaling pathways. Besides, HEP-1 promoted the production of beneficial bacteria in the gut, and increased the beneficial metabolites in liver through the gut-liver axis, consequently, resisting the occurrence of T2DM.

Effects of salvianolic acid A on intestinal microbiota and lipid metabolism disorders in Zucker diabetic fatty rats

Salvianolic acid A (SalA) is the main water-soluble component isolated from Salvia miltiorrhiza. This study explored the influences of SalA on intestinal microbiota composition and lipid metabolism in Zucker diabetic fatty (ZDF) rats. The 6-week-old male ZDF rats were treated with distilled water (N = 10) and low dose (SalA 0.5 mg/kg/d, N = 10), medium dose (SalA 1 mg/kg/d, N = 10), and high dose (SalA 2 mg/kg/d, N = 10) of SalA, with the male Zucker lean normoglycemic rats of the same week age as controls (given distilled water, N = 10). The blood glucose, body weight, and food intake of rats were examined. After 7 and 8 weeks of continuous administration, oral glucose tolerance test (OGTT) and insulin tolerance test (ITT) were performed, respectively. Serum fasting insulin (FINS), total cholesterol (TC), triglyceride (TG), and free fatty acid (FFA) were determined. Liver tissues were stained using hematoxylin-eosin (HE) and oil red O staining. Fecal samples were analyzed by 16S rRNA gene sequencing. Small intestinal tissues were stained using HE and immunohistochemistry. The tight junction proteins (ZO-1/Occludin/Claudin-1) and serum levels of LPS/TNF-α/IL-6 were evaluated. SalA reduced insulin resistance, liver injury, serum FFA, liver TC and TG levels in ZDF rats, and improved lipid metabolism. After SalA treatment, intestinal microbiota richness and diversity of ZDF rats were promoted. SalA retained the homeostasis of intestinal core microbiota. SalA reduced intestinal epithelial barrier damage, LPS, and inflammatory cytokines in ZDF rats. Overall, SalA can sustain intestinal microbiota balance and improve the lipid metabolism of ZDF rats.

Kolaviron attenuates cardiovascular injury in fructose-streptozotocin induced type-2 diabetic male rats by reducing oxidative stress, inflammation, and improving cardiovascular risk markers

The prevalence of cardiovascular disease among type-2 diabetic patients has become a source of major concern world over. This study explored the protective effect of kolaviron, a bioflavonoid, against oxidative cardiovascular injury in fructose- streptozotocin-induced type 2 diabetic male Sprague Dawley rats. After acclimatization, induction, and confirmation of type-2 diabetes, kolaviron was administered for 28days, after which the animals were anesthetized with Isofor and euthanized. Blood from each rat were collected, and blood samples were then centrifuged for serum and plasma. Cardiac troponin I (cTnI), creatine kinase myocardial band (CK-MB), Creatine phosphokinase (CK), and insulin levels were immediately determined in serum, while remaining samples (serum, plasma, and organs) were stored in the bio-freezer at - 80 °C and 10% formalin for enzyme-link immunosorbent assay (ELISA), biochemical, molecular, and histopathological studies. The results show that type-2 diabetes induction with fructose and streptozotocin led to increased blood glucose levels, decreased insulin levels and cardiac antioxidant enzyme activities, increased malondialdehyde levels, cardiac biomarkers and pro-inflammatory cytokines levels, resulted in abnormal lipid profile, increased blood pressure and angiotensin-converting enzyme (ACE) activity, and decreased plasma endothelial nitric oxide synthase (eNOS) concentration. The histopathological examination of the cardiac tissue revealed severe lesion, hypertrophy, and myofibrils degeneration. However, administration of kolaviron for 28days remarkably improved these conditions. Hence the result from the study validates the potency of kolaviron, and suggests it could serve as an alternative to existing remedy in ameliorating or protecting against cardiovascular injury in type-2 diabetes.