Diabetic‑induced alterations in hepatic glucose and lipid metabolism: The role of type 1 and type 2 diabetes mellitus (Review)

Hypoglycemic effect of orally administered resistant dextrins prepared with different acids on type 2 diabetes mice induced by high-fat diet and streptozotocin

A comparative study was performed to investigate the physicochemical properties and protective effects of hydrochloric acid-resistant dextrin (H-RD), citric acid-resistant dextrin (C-RD) and tartaric acid-resistant dextrin (T-RD) on the metabolic disorders and intestinal microbiota for type 2 diabetes mellitus (T2DM) mice. T-RD had the minimum molecular weight, with the highest short chain (DP 6-12) proportion and resistant starch content. After 4-week intervention with the three resistant dextrins, the body weight and fasting blood glucose of T2DM mice were improved significantly, accompanied by the reduction of serum indexes (TG, TC, LDL-C, ALT, AST, CRE, BUN, FINS, and GSP), but the serum HDL-C and liver glycogen levels increased. Among the three RDs intervention groups, T-RD showed the most significant improvement, followed by C-RD and finally H-RD. The 16 s rDNA results indicated that oral administration of resistant dextrins favored the proliferation of specific gut microbiota, including Faecalibaculum, Parabacteroides and Dubosiella, and reduced the ratio of Firmicutes/Bacteroidota, which is beneficial for reducing insulin resistance. Herein, the findings supported that the resistant dextrins exhibited a remission effect on T2DM, providing a basis for the development of functional food adjuvants for T2DM treatment.

Role of hypoxia-inducible factor 1 in type 1 diabetes

Type 1 diabetes (T1D) is a common autoimmune disease in which dysregulated glucose metabolism is a key feature. T1D is both poorly understood and in need of improved therapeutics. Hypoxia is frequently encountered in multiple tissues in T1D patients including the pancreas and sites of diabetic complications. Hypoxia-inducible factor (HIF)-1, a ubiquitous master regulator of the adaptive response to hypoxia, promotes glucose metabolism through transcriptional and non-transcriptional mechanisms and alters disease progression in multiple preclinical T1D models. However, how HIF-1 activation in β-cells of the pancreas and immune cells (two key cell types in T1D) ultimately affects disease progression remains controversial. We discuss recent advances in our understanding of the role of hypoxia/HIF-1-induced glycolysis in T1D and explore the possible use of drugs targeting this pathway as potential new therapeutics.

Exploring the therapeutic effects of sulforaphane: an in-depth review on endoplasmic reticulum stress modulation across different disease contexts

The endoplasmic reticulum (ER) is an intracellular organelle that contributes to the folding of proteins and calcium homeostasis. Numerous elements can disrupt its function, leading to the accumulation of proteins that are unfolded or misfolded in the lumen of the ER, a condition that is known as ER stress. This phenomenon can trigger cell death through the activation of apoptosis and inflammation. Glucoraphanin (GRA) is the predominant glucosinolate found in cruciferous vegetables. Various mechanical and biochemical processes activate the enzyme myrosinase, leading to the hydrolysis of glucoraphanin into the bioactive compound sulforaphane. Sulforaphane is an organosulfur compound that belongs to the isothiocyanate group. It possesses a wide range of activities and has shown remarkable potential as an anti-inflammatory, antioxidant, antitumor, and anti-angiogenic substance. Additionally, sulforaphane is resistant to oxidation, has been demonstrated to have low toxicity, and is considered well-tolerable in individuals. These properties make it a valuable natural dietary supplement for research purposes. Sulforaphane has been demonstrated as a potential candidate drug molecule for managing a range of diseases, primarily because of its potent antioxidant, anti-inflammatory, and anti-apoptotic properties, which can be mediated by modulation of ER stress pathways. This review seeks to cover a wealth of data supporting the broad range of protective functions of sulforaphane, improving various diseases, such as cardiovascular, central nervous system, liver, eye, and reproductive diseases, as well as diabetes, cancer, gastroenteritis, and osteoarthritis, through the amelioration of ER stress in both in vivo and in vitro studies.

Metformin attenuates high-carbohydrate diet-induced redox imbalance, inflammation, and mitochondrial dysfunction in Megalobrama amblycephala

This study aimed to investigate the effects of dietary metformin supplementation on the redox balance, inflammation, mitochondrial biogenesis, and function in blunt snout bream fed a high-carbohydrate (HC) diet. Fish (45.12 ± 0.36 g) were randomly offered four diets, including a control diet (33% carbohydrate), an HC diet (45% carbohydrate), and the HC diet supplemented with 0.06% (HCM1) and 0.12% (HCM2) metformin respectively for 12 weeks. Compared with the control, feeding the HC diet significantly increased the hepatosomatic index (HSI), the mesenteric fat index, liver and muscle glycogen contents, liver and adipose tissue lipid contents, plasma glucose and glycation end products (AGES) levels and aspartate transaminase activity, plasma and liver malondialdehyde (MDA) contents, hepatic adenosine triphosphate (ATP) and adenosine monophosphate (AMP) contents, mitochondrial cytochrome c content, mitochondrial complex IV activity and ATP 6 transcription, but decreased plasma catalase (CAT) activity, muscle superoxide dismutase (SOD) activity, hepatic antioxidant enzymes activities, and the transcriptions of transforming growth factor β (tgfβ) and interleukin 10 (il10). Compared with the HC group, metformin treatment (especially the HCM2 group) significantly elevated tissue glycogen contents, muscle SOD activity, plasma and liver antioxidant enzymes activities, the transcriptions of tgfβ and il10, the sodium/potassium ATPase activity, the contents of mitochondrial protein and AMP, the level of p-AMP activated protein kinase (AMPK), and the p-AMPK/t-AMPK ratio, but lowered the HSI, tissue lipid contents, plasma levels of glucose, AGES and glycated serum protein, plasma, and liver MDA contents, the transcriptions of il1β, NADH dehydrogenase subunit 1 and ATP 6, the contents of ATP and cytochrome c, the ATP/AMP ratio, and the activities of complexes I and IV. In conclusion, metformin could attenuate the HC diet-induced redox imbalance, inflammation, and mitochondrial dysfunction in blunt snout bream.

Interactions between intestinal microbiota and metabolites in zebrafish larvae exposed to polystyrene nanoplastics: Implications for intestinal health and glycolipid metabolism

Previous studies have shown the harmful effects of nanoscale particles on the intestinal tracts of organisms. However, the specific mechanisms remain unclear. Our present study focused on examining the uptake and distribution of polystyrene nanoplastics (PS-NPs) in zebrafish larvae, as well as its toxic effects on the intestine. It was found that PS-NPs, marked with red fluorescence, primarily accumulated in the intestine section. Subsequently, zebrafish larvae were exposed to normal PS-NPs (0.2-25 mg/L) over a critical 10-day period for intestinal development. Histopathological analysis demonstrated that PS-NPs caused structural changes in the intestine, resulting in inflammation and oxidative stress. Additionally, PS-NPs disrupted the composition of the intestinal microbiota, leading to alterations in the abundance of bacterial genera such as Pseudomonas and Aeromonas, which are associated with intestinal inflammation. Metabolomics analysis showed alterations in metabolites that are primarily involved in glycolipid metabolism. Furthermore, MetOrigin analysis showed a significant correlation between bacterial flora (Pedobacter and Bacillus) and metabolites (D-Glycerate 2-phosphate and D-Glyceraldehyde 3-phosphate), which are related to the glycolysis/gluconeogenesis pathways. These findings were further validated through alterations in multiple biomarkers at various levels. Collectively, our data suggest that PS-NPs may impair the intestinal health, disrupt the intestinal microbiota, and subsequently cause metabolic disorders.

A crucial role of adenosine deaminase in regulating gluconeogenesis in mice

Adenosine deaminase (ADA) catalyzes the irreversible deamination of adenosine (ADO) to inosine and regulates ADO concentration. ADA ubiquitously expresses in various tissues to mediate ADO-receptor signaling. A significant increase in plasma ADA activity has been shown to be associated with the pathogenesis of type 2 diabetes mellitus. Here, we show that elevated plasma ADA activity is a compensated response to high level of ADO in type 2 diabetes mellitus and plays an essential role in the regulation of glucose homeostasis. Supplementing with more ADA, instead of inhibiting ADA, can reduce ADO levels and decrease hepatic gluconeogenesis. ADA restores a euglycemic state and recovers functional islets in db/db and high-fat streptozotocin diabetic mice. Mechanistically, ADA catabolizes ADO and increases Akt and FoxO1 phosphorylation independent of insulin action. ADA lowers blood glucose at a slower rate and longer duration compared to insulin, delaying or blocking the incidence of insulinogenic hypoglycemia shock. Finally, ADA suppresses gluconeogenesis in fasted mice and insulin-deficient diabetic mice, indicating the ADA regulating gluconeogenesis is a universal biological mechanism. Overall, these results suggest that ADA is expected to be a new therapeutic target for diabetes.

Expressions of glycemic parameters, lipid profile, and thyroid hormone in patients with type 2 diabetes mellitus and their correlation

OBJECTIVE

This study aimed to investigate the expressions of glycemic parameters, lipid profile, and thyroid hormone in type 2 diabetes mellitus (T2DM) patients and their correlation.

METHODS

Eighty-four patients with T2DM in our hospital were included as the observation group. The T2DM patients were divided into mild group, moderate group, and severe group according to the fasting plasma glucose (FPG) level. Another 84 healthy subjects in the same period of health examination in our hospital were included as the control group. The levels of glycemic parameters, (HbA1c and FPG), lipid profile (TC, TG, LDL-C, and HDL-C) and thyroid hormone (FT3, TSH, and FT4) were measured by automatic biochemical analyzer. The correlation between glycemic parameters, lipid profile, and thyroid hormone was analyzed by Pearson correlation analysis.

RESULTS

The FPG, TC, TG, LDL-C, HbA1c, and TSH levels were significantly elevated, while the HDL-C and FT3 levels were significantly declined in the observation group versus to control group (p < .05). The levels of HbA1c, FPG, TC, LDL-C, and TSH were significantly increased, while the levels of HDL-C and FT3 were decreased in moderate and severe groups, when compared to mild group (p < .05). The levels of HbA1c, FPG, TC, LDL-C and TSH were higher, while the level of FT3 was lower in severe group than those in moderate group (p < .05). Pearson Correlation analysis showed that FT3 level in T2DM patients was positively correlated with FPG, HbAlc, TC, TG, and LDL-C levels (p < .05), but negatively correlated with HDL-C level (p < .05). TSH level was negatively correlated with FPG, HbAlc, TC, TG, and LDL-C levels (p < .05), while positively correlated with HDL-C level.

CONCLUSION

The thyroid hormone levels were of clinical significance in evaluating glycolipid metabolism and severity of T2DM. Clinical detection of glycolipid metabolism and thyroid hormone levels in T2DM patients is of great significance for diagnosis, evaluation, and targeted treatment of the disease.

Oleic Acid and Succinic Acid: A Potent Nutritional Supplement in Improving Hepatic Glycaemic Control in Type 2 Diabetic Sprague-Dawley Rats

Nutritional supplements are gaining traction for their effects in mitigating the impacts of various health conditions. In particular, many supplements are being proposed to reduce the impacts of type 2 diabetes (T2D), a metabolic condition that has reached global epidemic proportions. Recently, a supplement of oleic acid (OA) and succinic acid (SA; 1 : 1, w/w) was reported to improve glycaemic control in type 2 diabetic (T2D) Sprague-Dawley (S-D) rats through ameliorating insulin release and sensitivity. Here, we investigate the effects of the supplement (OA and SA) on hepatic and pancreatic function in T2D S-D rats. Eighteen (18) S-D rats were rendered diabetic and were divided into three equal groups: diabetic control, diabetic treatment, and diabetic glibenclamide. Another 12 S-D rats were obtained and served as the normal groups. The animals were treated daily with the vehicle, OA and SA (800 mg/kg body weight (bw); 1 : 1), or glibenclamide (10 mg/kg bw) which served as the positive control. The findings indicated that treatment with the supplement resulted in a 35.69 ± 4.22% reduction (p=0.006) in blood glucose levels (BGL). Analysis of hepatic enzymes depicted that the nutritional supplement reduced the activity of the gluconeogenesis enzyme, glucose-6-phosphatase (G6P) while improved the activity of catabolic enzymes such as glucose-6-phosphate dehydrogenase (G6PD) and pyruvate kinase (PK). Furthermore, the supplement attenuated oxidative stress through restoration of catalase (CAT) and superoxide dismutase (SOD), while reducing malondialdehyde (MDA) levels. Finally, the supplement showed no liver or kidney toxicity and improved the size and number of pancreatic islets of Langerhans, indicating its potential application in treating T2D. The study highlighted that a supplement of the two organic acids may be beneficial in reducing the rate of pathogenesis of type 2 diabetes. Therefore, it may offer therapeutic value as a dietary or nutritional supplement in the approach against diabetes and its complications.

Improvement of Theaflavins on Glucose and Lipid Metabolism in Diabetes Mellitus

In diabetes mellitus, disordered glucose and lipid metabolisms precipitate diverse complications, including nonalcoholic fatty liver disease, contributing to a rising global mortality rate. Theaflavins (TFs) can improve disorders of glycolipid metabolism in diabetic patients and reduce various types of damage, including glucotoxicity, lipotoxicity, and other associated secondary adverse effects. TFs exert effects to lower blood glucose and lipids levels, partly by regulating digestive enzyme activities, activation of OATP-MCT pathway and increasing secretion of incretins such as GIP. By the Ca2+-CaMKK ꞵ-AMPK and PI3K-AKT pathway, TFs promote glucose utilization and inhibit endogenous glucose production. Along with the regulation of energy metabolism by AMPK-SIRT1 pathway, TFs enhance fatty acids oxidation and reduce de novo lipogenesis. As such, the administration of TFs holds significant promise for both the prevention and amelioration of diabetes mellitus.

OMEF biochip for evaluating red blood cell deformability using dielectrophoresis as a diagnostic tool for type 2 diabetes mellitus

Type 2 diabetes mellitus (T2DM) is a prevalent and debilitating disease with numerous health risks, including cardiovascular diseases, kidney dysfunction, and nerve damage. One important aspect of T2DM is its association with the abnormal morphology of red blood cells (RBCs), which leads to increased blood viscosity and impaired blood flow. Therefore, evaluating the mechanical properties of RBCs is crucial for understanding the role of T2DM in cellular deformability. This provides valuable insights into disease progression and potential diagnostic applications. In this study, we developed an open micro-electro-fluidic (OMEF) biochip technology based on dielectrophoresis (DEP) to assess the deformability of RBCs in T2DM. The biochip facilitates high-throughput single-cell RBC stretching experiments, enabling quantitative measurements of the cell size, strain, stretch factor, and post-stretching relaxation time. Our results confirm the significant impact of T2DM on the deformability of RBCs. Compared to their healthy counterparts, diabetic RBCs exhibit ∼27% increased size and ∼29% reduced stretch factor, suggesting potential biomarkers for monitoring T2DM. The observed dynamic behaviors emphasize the contrast between the mechanical characteristics, where healthy RBCs demonstrate notable elasticity and diabetic RBCs exhibit plastic behavior. These differences highlight the significance of mechanical characteristics in understanding the implications for RBCs in T2DM. With its ∼90% sensitivity and rapid readout (ultimately within a few minutes), the OMEF biochip holds potential as an effective point-of-care diagnostic tool for evaluating the deformability of RBCs in individuals with T2DM and tracking disease progression.

Comparative Screening of the Liver Gene Expression Profiles from Type 1 and Type 2 Diabetes Rat Models

Experimental animal models of diabetes can be useful for identifying novel targets related to disease, for understanding its physiopathology, and for evaluating emerging antidiabetic treatments. This study aimed to characterize two rat diabetes models: HFD + STZ, a high-fat diet (60% fat) combined with streptozotocin administration (STZ, 35 mg/kg BW), and a model with a single STZ dose (65 mg/kg BW) in comparison with healthy rats. HFD + STZ- induced animals demonstrated a stable hyperglycemia range (350-450 mg/dL), whereas in the STZ-induced rats, we found glucose concentration values with a greater dispersion, ranging from 270 to 510 mg/dL. Moreover, in the HFD + STZ group, the AUC value of the insulin tolerance test (ITT) was found to be remarkably augmented by 6.2-fold higher than in healthy animals (33,687.0 ± 1705.7 mg/dL/min vs. 5469.0 ± 267.6, respectively), indicating insulin resistance (IR). In contrast, a more moderate AUC value was observed in the STZ group (19,059.0 ± 3037.4 mg/dL/min) resulting in a value 2.5-fold higher than the average exhibited by the control group. After microarray experiments on liver tissue from all animals, we analyzed genes exhibiting a fold change value in gene expression <-2 or >2 (p-value <0.05). We found 27,686 differentially expressed genes (DEG), identified the top 10 DEGs and detected 849 coding genes that exhibited opposite expression patterns between both diabetes models (491 upregulated genes in the STZ model and 358 upregulated genes in HFD + STZ animals). Finally, we performed an enrichment analysis of the 849 selected genes. Whereas in the STZ model we found cellular pathways related to lipid biosynthesis and metabolism, in the HFD + STZ model we identified pathways related to immunometabolism. Some phenotypic differences observed in the models could be explained by transcriptomic results; however, further studies are needed to corroborate these findings. Our data confirm that the STZ and the HFD + STZ models are reliable experimental models for human T1D and T2D, respectively. These results also provide insight into alterations in the expression of specific liver genes and could be utilized in future studies focusing on diabetes complications associated with impaired liver function.

Phytochemical analysis and antihyperglycemic activity of Castilleja arvensis

Castilleja genus comprises approximately 211 species, some of them exhibiting potential in treating various diseases. Remarkably, despite its abundance, there is a significant lack of scientific studies that explore the chemical composition and/or therapeutic activity of this genus. In this work, the chemical composition of Castilleja arvensis was determined, and its antihyperglycemic activity was evaluated in vivo, in vitro, and ex vivo. Hydroalcoholic extract of C. arvensis (HECa) was obtained from the maceration of aerial parts. HECa was fractionated by liquid-liquid extractions to obtain the CH2Cl2 fraction (DF), EtOAc fraction (EF), n-BuOH fraction (BF) and aqueous residue (AR). The antihyperglycemic activity was determined in vivo through oral glucose and sucrose tolerance tests in normoglycemic CD-1 mice. Ex vivo assays were performed to determine intestinal glucose absorption, muscular glucose uptake and hepatic glucose production. α-glucosidase inhibitory activity was evaluated in vitro. Phytochemical screening was carried out through conventional chromatography techniques. Structure elucidation of the isolated compounds was performed by GC-MS and NMR experiments. HECa, its fractions and AR showed significant antihyperglycemic activity in vivo. According to the in vitro and ex vivo assays, this effect can be attributed to different mechanisms of action, including a delay in intestinal glucose absorption, an improvement in insulin sensitivity, and the regulation of hepatic glucose production. These effects may be due to different metabolites identified in fractions from the HECa, including genkwanin, acacetin, verbascoside and ipolamiide. Thus, current research shows that C. arvensis is an important source of bioactive compounds for the management of glycemia.

Triglyceride-Glucose Index As A Biomarker Of Insulin Resistance, Diabetes Mellitus, Metabolic Syndrome, And Cardiovascular Disease: A Review

The triglyceride-glucose (TyG) index is one of the parameters that have been used in assessing insulin resistance. Triglycerides and fasting blood glucose are two low-cost, common laboratory indicators that are used to compute the TyG index. This article reviews the link between the TyG index and several aspects concerning insulin resistance-related disorders and cardiovascular disease, as well as the use of various TyG index cutoffs in the above conditions with sensitivity and specificity, respectively, in various populations in the world.

A comparison between different human hepatocyte models reveals profound differences in net glucose production, lipid composition and metabolism in vitro

Hepatocytes are responsible for maintaining a stable blood glucose concentration during periods of nutrient scarcity. The breakdown of glycogen and de novo synthesis of glucose are crucial metabolic pathways deeply interlinked with lipid metabolism. Alterations in these pathways are often associated with metabolic diseases with serious clinical implications. Studying energy metabolism in human cells is challenging. Primary hepatocytes are still considered the golden standard for in vitro studies and have been instrumental in elucidating key aspects of energy metabolism found in vivo. As a result of several limitations posed by using primary cells, a multitude of alternative hepatocyte cellular models emerged as potential substitutes. Yet, there remains a lack of clarity regarding the precise applications for which these models accurately reflect the metabolic competence of primary hepatocytes. In this study, we compared primary hepatocytes, stem cell-derived hepatocytes, adult donor-derived liver organoids, immortalized Upcyte-hepatocytes and the hepatoma cell line HepG2s in their response to a glucose production challenge. We observed the highest net glucose production in primary hepatocytes, followed by organoids, stem-cell derived hepatocytes, Upcyte-hepatocytes and HepG2s. Glucogenic gene induction was observed in all tested models, as indicated by an increase in G6PC and PCK1 expression. Lipidomic analysis revealed considerable differences across the models, with organoids showing the closest similarity to primary hepatocytes in the common lipidome, comprising 347 lipid species across 19 classes. Changes in lipid profiles as a result of the glucose production challenge showed a variety of, and in some cases opposite, trends when compared to primary hepatocytes.

Insulin therapy among diabetic patients in rural communities of Sub-Saharan Africa: a perspective review

In this perspective review, we describe a brief background on the status quo of diabetes mellitus-related therapies and glycemic control among patients in rural communities in sub-Saharan Africa. The article discusses insulin therapy as well as the difficulties in obtaining insulin and oral hypoglycemic medications for diabetic patients living in sub-Saharan Africa. We wrap up our discussion with suggestions on solutions and opportunities for future research to tackle this health challenge in these impoverished communities. We conducted a literature search from PubMed and Google Scholar up until August 2023. Key words were used to generate search terms used to retrieve the required information. All types of literature with pertinent information on the current topic were included in the study. Diabetes mellitus is on the rise in sub-Saharan Africa. Several studies have reported poor glycemic control, low screening rates for diabetes mellitus, cigarette smoking, high alcohol consumption, prescription of antidiabetic therapy, and associated costs as contributors to the uptake of antidiabetic treatment. Although there is paucity of data on the extent of insulin therapy uptake and its possible modifiable contributors among the diabetic patients in the region, the anticipated increase in the number of people with diabetes on the continent makes it critical for global leaders to address the research gaps in insulin therapy among rural communities of sub-Saharan Africa, thus reducing the burden of diabetes in these populations.

The Potential of the Adzuki Bean (Vigna angularis) and Its Bioactive Compounds in Managing Type 2 Diabetes and Glucose Metabolism: A Narrative Review

Type 2 diabetes (T2D) is a common noncommunicable disease. In the United States alone, 37 million Americans had diabetes in 2017. The adzuki bean (Vigna angularis), a legume, has been reported to possess antidiabetic benefits. However, the extent and specific mechanisms through which adzuki bean consumption may contribute to T2D prevention and management remain unclear. Therefore, the aim of this narrative review is to analyze current evidence supporting the utilization of adzuki beans in the diet as a strategy for preventing and managing T2D. Animal studies have demonstrated a positive impact of adzuki beans on managing T2D. However, supporting data from humans are limited. Conversely, the potential of adzuki bean consumption in preventing T2D via modulating two T2D risk factors (obesity and dyslipidemia) also lacks conclusive evidence. Animal studies have suggested an inconsistent and even contradictory relationship between adzuki bean consumption and the management of obesity and dyslipidemia, in which both positive and negative relationships are reported. In sum, based on the existing scientific literature, this review found that the effects of adzuki bean consumption on preventing and managing T2D in humans remain undetermined. Consequently, human randomized controlled trials are needed to elucidate the potential benefits of the adzuki bean and its bioactive components in the prevention and management of T2D.

Glycolytic enzymes in non-glycolytic web: functional analysis of the key players

To survive in the tumour microenvironment, cancer cells undergo rapid metabolic reprograming and adaptability. One of the key characteristics of cancer is increased glycolytic selectivity and decreased oxidative phosphorylation (OXPHOS). Apart from ATP synthesis, glycolysis is also responsible for NADH regeneration and macromolecular biosynthesis, such as amino acid biosynthesis and nucleotide biosynthesis. This allows cancer cells to survive and proliferate even in low-nutrient and oxygen conditions, making glycolytic enzymes a promising target for various anti-cancer agents. Oncogenic activation is also caused by the uncontrolled production and activity of glycolytic enzymes. Nevertheless, in addition to conventional glycolytic processes, some glycolytic enzymes are involved in non-canonical functions such as transcriptional regulation, autophagy, epigenetic changes, inflammation, various signaling cascades, redox regulation, oxidative stress, obesity and fatty acid metabolism, diabetes and neurodegenerative disorders, and hypoxia. The mechanisms underlying the non-canonical glycolytic enzyme activities are still not comprehensive. This review summarizes the current findings on the mechanisms fundamental to the non-glycolytic actions of glycolytic enzymes and their intermediates in maintaining the tumor microenvironment.

Dehulled Adlay (Coix lachryma-jobi L.) ameliorates hepatic gluconeogenesis and steatosis in streptozotocin/high-fat diet-induced diabetic rats

Adlay (Coix lachryma-jobi L.) is a traditional Chinese herbal medicine with various biological activities. We investigated the anti-diabetic effects of different parts of adlay seeds, including polished adlay (PA), adlay bran (AB) and dehulled adlay (DA) in a streptozotocin (STZ)/high fat diet (HFD) diabetic rat model (DM). DM rats supplemented with or without PA (43%), AB (3%), or DA (46%) diet for 8 weeks. The plasma glucose and insulin levels and the insulin resistance index (HOMA-IR) were increased in DM group; among the three adlay diets, DA has the best effects attenuating all of these alterations in DM rats. Both AB and DA alleviated diabetes-impaired glucose tolerance. The increased hepatic phosphoenolpyruvate carboxykinase protein expression in DM group was improved by all of the three adlay diets. The increased ratio of glucose-6-phosphatase to glucokinase in DM group was suppressed by DA supplementation, further suggesting DA diet is most effective among the three diets. Both AB and DA diets had beneficial effects against hepatic steatosis, with better effects observed in DA group. These results suggest that the DA diet, composed of both polished adlay and adlay bran, possesses the best potential to improve glucose homeostasis, at least in part, by alleviating hepatic glucose metabolism and steatosis.

Chronic exposure to nanocellulose altered depression-related behaviors in mice on a western diet: The role of immune modulation and the gut microbiome

AIMS

To determine if cellulose nanofibrils (CNF) have potential applications as food additives.

MATERIALS AND METHODS

Male C57BL/6 mice on a Western diet were exposed to CNF for one month at a dose of 30 mg/kg by gavage. Male NOD mice, a model for type 1 diabetes (T1D), were used in a six-month study.

KEY FINDINGS

Sequencing analysis of 16S rRNA genes suggested significant changes in gut microbiome of male C57BL/6 mice exposed to CNF. Analysis of functional metagenomics indicated that many of the functional contents that might be altered following CNF ingestion were associated with lipid and carbohydrate processing. Further studies in NOD mice suggested that there were some decreases in the blood glucose levels during the insulin tolerance test and glucose tolerance test following CNF treatment. However, these small decreases were not considered biologically meaningful as there were no significant changes in either the area under the curve or the first-order rate constant for glucose disappearance. Moreover, serum concentrations of cytokines/chemokines including IL-3, IL-12(p70) and the keratinocyte chemoattractant were increased following chronic exposure to CNF. In addition, behavioral studies suggested that the percentage of immobility time during the tail-suspension test was significantly increased following six months of exposure to CNF in NOD mice, signifying an increase in depression-related behavior.

SIGNIFICANCE

Collectively, long-term CNF consumption was associated with changes in the ecology of the gut microbiome, immune homeostasis, and possibly energy metabolism and mental health in male NOD mice on a Western diet.

Mango (Mangifera indica L.) seed kernel extract suppresses hyperglycemia by modulating pancreatic β cell apoptosis and dysfunction and hepatic glucose metabolism in diabetic rats

This study investigated the anti-hyperglycemic action of mango seed kernel extract (MKE) and various mechanisms involved in its actions to improve pancreatic β cells and hepatic carbohydrate metabolism in diabetic rats. An intraperitoneal injection of 60 mg/kg of streptozotocin (STZ) followed by 30 consecutive days of treatment with MKE (250, 500, and 1000 mg/kg body weight) was used to establish a study group of diabetic rats. Using liquid chromatography-electrospray ionization-quadrupole time-of-flight mass spectrometry (LC-ESI-QTOF-MS/MS) for identification, 26 chemical compounds were found in MKE and the high-performance liquid chromatography (HPLC) analysis of the MKE also revealed the existence of mangiferin, gallic acid, and quercetin. The results confirmed that in each diabetes-affected rat, MKE mitigated the heightened levels of fasting blood glucose, diabetic symptoms, glucose intolerance, total cholesterol (TC), and low-density lipoprotein-cholesterol (LDL-C). As demonstrated by a remarkable increment in serum and pancreatic insulin, the diabetic pancreatic β cell function was potentiated by treating with MKE. The effect of MKE on diabetic pancreatic apoptosis clearly reduced the terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL)-positive cells, which was related to diminished levels of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and Bax and an increase in Bcl-xL protein expression. Furthermore, diabetes-induced liver damage was clearly ameliorated along with a notable reduction in serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels and abnormal liver histology. By enhancing anti-oxidant superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) activities, MKE alleviated diabetes-induced pancreatic and liver oxidative damage, as demonstrated by diminished levels of malondialdehyde. In minimizing the expression levels of glucose 6-phosphatase and phosphoenolpyruvate carboxykinase-1 proteins in the diabetic liver, MKE also enhanced glycogen content and hexokinase activity. Collectively, these findings indicate that by suppressing oxidative and inflammatory processes, MKE exerts a potent anti-hyperglycemic activity in diabetic rats which serve to protect pancreatic β cell apoptosis, enhance their function, and improve hepatic glucose metabolism.

Evaluating the Potential of Plukenetia volubilis Linneo (Sacha Inchi) in Alleviating Cardiovascular Disease Risk Factors: A Mini Review

Plukenetia volubilis Linneo or Sacha Inchi (SI), a traditional natural remedy indigenous to Peru and Brazil, has garnered global attention due to its exceptional nutritional composition. Its protective effects against various non-communicable diseases, notably cardiovascular disease (CVD), have become a subject of interest in recent research. This comprehensive review summarizes the existing evidence from 15 relevant articles concerning the impact of SI on common CVD risk factors, including dyslipidemia, obesity, diabetes, and hypertension. The relevant articles were derived from comprehensive searches on PubMed, Scopus, Google Scholar, and Web of Science using predefined criteria and keywords related to the topic. Overall, SI demonstrated positive effects in attenuating dyslipidemia, obesity, diabetes, and hypertension. The multifaceted mechanisms responsible for the protective effects of SI against these CVD risk factors are primarily attributed to its antioxidative and anti-inflammatory properties. While preclinical studies dominate the current scientific literature on SI, there are limited clinical trials to corroborate these findings. Therefore, future well-designed, large-scale randomized clinical trials are highly recommended to establish the efficacy of SI and determine its optimal dosage, potential drug and food interactions, and practical integration into preventive strategies and dietary interventions for the high-risk populations.

Crosstalk between autophagy and insulin resistance: evidence from different tissues

Insulin is a critical hormone that promotes energy storage in various tissues, as well as anabolic functions. Insulin resistance significantly reduces these responses, resulting in pathological conditions, such as obesity and type 2 diabetes mellitus (T2DM). The management of insulin resistance requires better knowledge of its pathophysiological mechanisms to prevent secondary complications, such as cardiovascular diseases (CVDs). Recent evidence regarding the etiological mechanisms behind insulin resistance emphasizes the role of energy imbalance and neurohormonal dysregulation, both of which are closely regulated by autophagy. Autophagy is a conserved process that maintains homeostasis in cells. Accordingly, autophagy abnormalities have been linked to a variety of metabolic disorders, including insulin resistance, T2DM, obesity, and CVDs. Thus, there may be a link between autophagy and insulin resistance. Therefore, the interaction between autophagy and insulin function will be examined in this review, particularly in insulin-responsive tissues, such as adipose tissue, liver, and skeletal muscle.

Effects of maternal high-fat diet on fetal growth, placental nutrient transporters and circular RNA expression profiles

Epidemiological and experimental studies suggest that there is a strong correlation between maternal high-fat diet and fetal-placental development. The current study aims to investigate the effects of maternal high-fat diet on fetal growth, placental nutrient transporters and circular RNA expression profiles in a mouse model. Forty C57BL/6 female mice were randomly assigned to two groups, fed either a control (10% fat for energy) diet (CON) or a high-fat (60% fat for energy) diet (HFD) for 4 weeks before mating and throughout pregnancy, and were killed on day 19.5 of pregnancy. The serum glucose, total cholesterol and low-density lipoprotein, the glucolipid metabolism-related hormones, and the insulin resistance index were significantly increased. High-throughput sequencing showed that differentially expressed circRNAs (DE circRNAs) in the placenta can regulate various biological processes, cellular components, and molecular functions through various energy metabolism pathways, and mmu-let-7g-5p was found to target and bind to multiple DE circRNAs. In addition, this study also predicted that various circRNAs with protein coding functions can regulate maternal placental nutrient transport. In general, the ceRNA (circRNAs-miRNAs-mRNAs) regulatory network of maternal placental nutrient transport constructed in this study is of great significance for further understanding the effect of maternal nutrition on fetal growth in the future.

Anti-Diabetic Effect of Lactobacillus Paracasei Isolated from Malaysian Water Kefir Grains

The prevalence of type 2 diabetes mellitus (T2DM) is alarming because it is always linked to the increase in chronic diseases, mortality, and socioeconomic burden. Water kefir has a wide range of functional and probiotic characteristics attributed to the microorganisms present in the kefir grains. The present study aims to evaluate the in vivo anti-diabetic potential of the isolated Lactobacillus paracasei from Malaysian water kefir grains (MWKG) which was reported to have excellent probiotic properties and high antioxidant activities as reported previously. High-fat diet/streptozotocin (HFD/STZ) induction was used to obtain a T2DM model followed by treatment with the isolated L. paracasei from MWKG. The levels of glucose, insulin, and in vivo liver antioxidants were quantified after 14 weeks. Gene expression analysis of the liver was also carried out using microarray analysis, and several genes were selected for validation using quantitative real-time PCR. Insulin tolerance test demonstrated that the L. paracasei isolated from the MWKG alleviated T2DM by improving the area under the curve of the insulin tolerance test whereby low-dose and high-dose concentrations treated groups showed 2424.50 ± 437.02 mmol/L·min and 2017.50 ± 347.09 mmol/L·min, respectively, compared to untreated diabetic mice which was 3884.50 ± 39.36 mmol/L·min. Additionally, treatment with the isolated L. paracasei from MWKG regulated the expression of several genes related to glucose homeostasis and lipid metabolism in diabetic mice. These results suggested that the isolated L. paracasei from MWKG could be a potential dietary supplement for T2DM.

Oral administration of Bifidobacterium longum WHH2270 ameliorates type 2 diabetes in rats

Accumulating evidence suggests that specific probiotic strains exert hypoglycemic effects on type 2 diabetes mellitus (T2DM), and probiotic strains within Bifidobacterium exhibit potential beneficial effects on T2DM. In this study, α-glucosidase inhibitory activities of 14 Bifidobacterium strains were assessed in vitro. The hypoglycemic effects of Bifidobacterium longum WHH2270 with high α-glucosidase inhibitory activity (42.03%) were then investigated in a high-fat diet/streptozotocin-induced T2DM rat model. Oral administration of WHH2270 (4 × 109 CFU/kg/day) for 8 weeks significantly reversed the reduced body weight and ameliorated the levels of fasting blood glucose, serum triglyceride, serum total cholesterol, glucose tolerance, and insulin resistance in T2DM rats. Using 16S rRNA high-throughput sequencing of feces, WHH2270 was revealed to reshape the gut microbiome composition by increasing the abundances of Lactobacillus and Bifidobacterium and decreasing the abundances of UCG_005, Clostridium, and Faecalibacterium in T2DM rats. Besides, the fecal levels of short-chain fatty acids (SCFAs) including acetate, propionate, and butyrate were also elevated after WHH2270 administration. Moreover, the gene expressions of SCFA receptors FFAR2 and FFAR3 in the colon and pancreas of T2DM rats were restored by WHH2270 administration, accompanied by increased levels of serum acetate. In summary, these results provide evidence that WHH2270 has the potential to improve T2DM symptoms by alleviating hyperglycemia, which was associated with changes in the gut microbiome composition and SCFA production. PRACTICAL APPLICATION: Bifidobacterium longum WHH2270 with high α-glucosidase inhibitory activity may serve as a promising hypoglycemic agent for the treatment of T2DM.

Effect of heterologous platelet-rich plasma on liver and modulation of glucose metabolism and Wnt signalling pathways in diabetic mice

BACKGROUND

The current study was designed to highlight the effects of heterologous platelet-rich plasma (PRP) on deteriorated hepatic tissues and impaired glucose metabolism of alloxan-induced diabetic mice.

METHODS

30 male mice were divided into a control (CG), PRP (PG), diabetic (DG), and two treated groups (T1G and T2G). PG was given PRP treatment (0.5 ml/kg body weight) twice a week for four weeks. DG, T1G and T2G were given alloxan (150 mg/kg) to induce diabetes. After confirmation, PRP treatment was given to T1G and T2G for two and four weeks respectively while DG was left untreated. Upon completion of the said experimental period, liver samples were taken for histological and gene expression analyses.

RESULTS

The study found that the liver tissue of the DG group showed signs of damage, including hepatocyte ballooning, sinusoid dilatation, and collagen deposition. However, these changes were significantly reduced in both T1G and T2G groups. The expression of several genes related to liver function was also affected, with upregulation of Fbp1 and Pklr, and downregulation of Pck1 in the DG group. PRP treatment restored Fbp1 expression and also increased the expression of glycolytic pathway genes Hk1 and Gck, as well as Wnt signalling pathway genes Wnt2, Wnt4, and Wnt9a in both treated groups.

CONCLUSION

Current study revealed that heterologous PRP may partly alleviate high glucose levels in diabetics possibly by mediating glucose metabolism via inhibition of Wnt signalling pathway.

The immune and metabolic treatment approach of using testosterone on mice models of liver injury

Background: Natural killer (NK) cells showed an anti-fibrotic effect; however, their function is thought to be impaired in advanced liver injury. In the current study, we aimed to assess the immune and metabolic impact of testosterone on mice models of liver injury. Methods: Carbon-tetrachloride induced liver fibrosis male mice models was i.p injected for 2 weeks (acute) and 4 weeks (chronic) (n = 36). Testosterone (4 mg/kg mouse body weight) was injected i.p. following the first week of the acute model of CCl4 and following the second week of the chronic model of CCl4. At the end of the experiments, mice were sacrificed, and serum was collected for assessing liver enzymes of ALT and AST, as well as inflammatory markers of IL-6, metabolic makers of C-peptide levels, and lipid and glucose profiles. Livers were harvested and used for histological assessments for inflammation and fibrosis. Fibrosis profiles from liver extracts, αSMA and Collagen III, were assessed by RT-PCR. Moreover, liver tissue-resident NK cells were isolated and evaluated for their activity by assessing INF-γ and IL-6 receptors using ELISA and flow cytometry, respectively. Results: Serum ALT, AST, and IL-6, as well as metabolic assessments of cholesterol, triglyceride, C-peptide, fasting blood sugar, and fibrotic profiles, were linearly correlated with disease progressions. Histological characterization of the liver was worsened in the chronic model of liver injury. Testosterone-treated mice exhibit a significant reduction in collagen depositions with less dense fibrosis tissue associated with reduced liver injury enzymes and metabolic markers in both the acute and chronic CCl4 mice models in favor of the latter one (p < 0.05). Moreover, testosterone treatments displayed a significant decrease in serum IL-6 of 2.4-fold (p = 0.0001) and 2.3-fold (p = 0.0003) in the acute and chronic models, respectively (p = 0.002), and data showed an increase in INF-γ release from NK associated with a reduction in their IL-6 receptor expressions (p < 0.05). Conclusion: Our results indicated effects of testosterone on mediating a decreased expressions of NK IL-6 receptors and consequently inducing their activation; which in part, could explain the amelioration of liver injury. Our data suggest an anti-inflammatory and anti-fibrotic treatment approach of using testosterone for delaying disease progressions.

Peripheral origin exosomal microRNAs aggravate glymphatic system dysfunction in diabetic cognitive impairment

Cognitive dysfunction is one of the common central nervous systems (CNS) complications of diabetes mellitus, which seriously affects the quality of life of patients and results in a huge economic burden. The glymphatic system dysfunction mediated by aquaporin-4 (AQP4) loss or redistribution in perivascular astrocyte endfeet plays a crucial role in diabetes-induced cognitive impairment (DCI). However, the mechanism of AQP4 loss or redistribution in the diabetic states remains unclear. Accumulating evidence suggests that peripheral insulin resistance target tissues and CNS communication affect brain homeostasis and that exosomal miRNAs are key mediators. Glucose and lipid metabolism disorder is an important pathological feature of diabetes mellitus, and skeletal muscle, liver and adipose tissue are the key target insulin resistance organs. In this review, the changes in exosomal miRNAs induced by peripheral metabolism disorders in diabetes mellitus were systematically reviewed. We focused on exosomal miRNAs that could induce low AQP4 expression and redistribution in perivascular astrocyte endfeet, which could provide an interorgan communication pathway to illustrate the pathogenesis of DCI. Furthermore, the mechanisms of exosome secretion from peripheral insulin resistance target tissue and absorption to the CNS were summarized, which will be beneficial for proposing novel and feasible strategies to optimize DCI prevention and/or treatment in diabetic patients.

An Ethyl Acetate Extract of Eryngium carlinae Inflorescences Attenuates Oxidative Stress and Inflammation in the Liver of Streptozotocin-Induced Diabetic Rats

Secondary metabolites such as flavonoids are promising in the treatment of non-alcoholic fatty liver disease (NAFLD), which is one of the complications of diabetes due to oxidative stress and inflammation. Some plants, such as Eryngium carlinae, have been investigated regarding their medicinal properties in in vitro and in vivo assays, showing favorable results for the treatment of various diseases such as diabetes and obesity. The present study examined the antioxidant and anti-inflammatory effects of the phenolic compounds present in an ethyl acetate extract of the inflorescences of Eryngium carlinae on liver homogenates and mitochondria from streptozotocin (STZ)-induced diabetic rats. Phenolic compounds were identified and quantified by UHPLC-MS. In vitro assays were carried out to discover the antioxidant potential of the extract. Male Wistar rats were administered with a single intraperitoneal injection of STZ (45 mg/kg) and were given the ethyl acetate extract at a level of 30 mg/kg for 60 days. Phytochemical assays showed that the major constituents of the extract were flavonoids; in addition, the in vitro antioxidant activity was dose dependent with IC50 = 57.97 mg/mL and IC50 = 30.90 mg/mL in the DPPH and FRAP assays, respectively. Moreover, the oral administration of the ethyl acetate extract improved the effects of NAFLD, decreasing serum and liver triacylglycerides (TG) levels and oxidative stress markers and increasing the activity of the antioxidant enzymes. Likewise, it attenuated liver damage by decreasing the expression of NF-κB and iNOS, which lead to inflammation and liver damage. We hypothesize that solvent polarity and consequently chemical composition of the ethyl acetate extract of E. carlinae, exert the beneficial effects due to phenolic compounds. These results suggest that the phenolic compounds of the ethyl acetate extract of E. carlinae have antioxidant, anti-inflammatory, hypolipidemic, and hepatoprotective activity.

The genetics of a "femaleness/maleness" score in cardiometabolic traits in the UK biobank

We recently devised continuous "sex-scores" that sum up multiple quantitative traits, weighted by their respective sex-difference effect sizes, as an approach to estimating polyphenotypic "maleness/femaleness" within each binary sex. To identify the genetic architecture underlying these sex-scores, we conducted sex-specific genome-wide association studies (GWASs) in the UK Biobank cohort (females: n = 161,906; males: n = 141,980). As a control, we also conducted GWASs of sex-specific "sum-scores", simply aggregating the same traits, without weighting by sex differences. Among GWAS-identified genes, while sum-score genes were enriched for genes differentially expressed in the liver in both sexes, sex-score genes were enriched for genes differentially expressed in the cervix and across brain tissues, particularly for females. We then considered single nucleotide polymorphisms with significantly different effects (sdSNPs) between the sexes for sex-scores and sum-scores, mapping to male-dominant and female-dominant genes. Here, we identified brain-related enrichment for sex-scores, especially for male-dominant genes; these findings were present but weaker for sum-scores. Genetic correlation analyses of sex-biased diseases indicated that both sex-scores and sum-scores were associated with cardiometabolic, immune, and psychiatric disorders.

Roles of malate and aspartate in gluconeogenesis in various physiological and pathological states

Gluconeogenesis, a pathway for glucose synthesis from non-carbohydrate substances, begins with the synthesis of oxaloacetate (OA) from pyruvate and intermediates of citric acid cycle in hepatocyte mitochondria. The traditional view is that OA does not cross the mitochondrial membrane and must be shuttled to the cytosol, where most enzymes involved in gluconeogenesis are compartmentalized, in the form of malate. Thus, the possibility of transporting OA in the form of aspartate has been ignored. In the article is shown that malate supply to the cytosol increases only when fatty acid oxidation in the liver is activated, such as during starvation or untreated diabetes. Alternatively, aspartate synthesized from OA by mitochondrial aspartate aminotransferase (AST) is transported to the cytosol in exchange for glutamate via the aspartate-glutamate carrier 2 (AGC2). If the main substrate for gluconeogenesis is an amino acid, aspartate is converted to OA via urea cycle, therefore, ammonia detoxification and gluconeogenesis are simultaneously activated. If the main substrate is lactate, OA is synthesized by cytosolic AST, glutamate is transported to the mitochondria through AGC2, and nitrogen is not lost. It is concluded that, compared to malate, aspartate is a more suitable form of OA transport from the mitochondria for gluconeogenesis.

Effects of the in-utero dicyclohexyl phthalate and di-n-hexyl phthalate administration on the oxidative stress-induced histopathological changes in the rat liver tissue correlated with serum biochemistry and hematological parameters

Phthalates are widely used as plasticizers in the industry and are found in cosmetics, food and drink packaging, drugs, toys, households, medical devices, pesticides, personal care products, and paints. Phthalates exert endocrine disrupting and peroxisome proliferator effects in humans and wildlife associated with the pathogenesis of various diseases, including diabetes, obesity, infertility, cardiovascular diseases, metabolic syndrome, and cancer. Since phthalates are metabolized in the liver, which regulates the body's energy metabolism, long or short-term exposure to the phthalates is associated with impaired glucose, lipid, and oxidative stress metabolisms contributing to liver toxicity. However, the impact of in-utero exposure to DHP and DCHP on liver metabolism has not been studied previously. Thus, in this study, we evaluated serum biochemistry parameters, hematological markers, histopathological changes, and oxidative and pentose phosphate pathway (PPP) metabolisms in the liver following in-utero DHP and DCHP administration, respectively, in male and female rats. We found increased relative and absolute liver weights and impaired triglyceride, alanine transaminase (ALT), lactate dehydrogenase (LDH), and alkaline phosphatase (ALP) levels upon dicyclohexyl phthalate (DCHP) and di-n-hexyl phthalate (DHP). Histopathological changes, including congestion, sinusoidal dilatation, inflammatory cell infiltration, cells with a pyknotic nucleus, lysis of hepatocytes, and degeneration of hepatic parenchyma have been observed in the liver samples of DHP and DCHP dose groups. Moreover, increased glutathione s-transferase (GST), glucose 6-phosphate dehydrogenase (G6PD), and glutathione reductase (GR) activities have been found in the liver samples of DHP and DCHP-treated rats associated with impaired pentose phosphate pathway (PPP) and oxidative stress metabolism. First time in the literature, we showed that in-utero exposure to DHP and DCHP causes liver damage associated with impaired oxidative stress metabolism in male and female rats. Our data may guide researchers and governments to regulate and restrict phthalates in industrial products.

Integration of network pharmacology, transcriptomics and molecular docking reveals two novel hypoglycemic components in snow chrysanthemum

Our previous studies uncovered the glucose-lowering properties of snow chrysanthemum tea, however, the active ingredients and underlying mechanisms were yet to be uncovered. Flavonoids are the most active and abundant components in snow chrysanthemum tea. In this study, we treated leptin-deficient diabetic ob/ob or high-fat diet (HFD)-induced C57BL/6 J obese mice with or without total flavonoids of snow chrysanthemum (TFSC) for 14 weeks. Results indicated that TFSC ameliorated dyslipidemia and fatty liver, thereby reducing hyperlipidemia. Further mechanism experiments, including RNA-seq and experimental validation, revealed TFSC improved glycolipid metabolism primarily by activating the AMPK/Sirt1/PPARγ pathway. Additionally, by integrating UPLC, network pharmacology, transcriptomics, and experimental validation, we identified two novel hypoglycemic compounds, sulfuretin and leptosidin, in TFSC. Treatment with 12.5 μmol/L sulfuretin obviously stimulated cellular glucose consumption, and sulfuretin (3.125, 6.25 and 12.5 μmol/L) significantly mitigated glucose uptake damage and reliably facilitated glucose consumption in insulin-resistant HepG2 cells. Remarkably, sulfuretin interacted with the ligand-binding pocket of PPARγ via three hydrogen bond interactions with the residues LYS-367, GLN-286 and TYR-477. Furthermore, a concentration of 12.5 μmol/L sulfuretin effectively upregulated the expression of PPARγ, exhibiting a comparable potency to a renowned PPARγ agonist at 20 μmol/L. Taken together, our findings have identified two new hypoglycemic compounds and revealed their mechanisms, which significantly expands people's understanding of the active components in snow chrysanthemum that have hypoglycemic effects.

Hepatic Insulin Resistance Model in the Male Wistar Rat Using Exogenous Insulin Glargine Administration

Metabolic diseases are a worldwide health problem. Insulin resistance (IR) is their distinctive hallmark. For their study, animal models that provide reliable information are necessary, permitting the analysis of the cluster of abnormalities that conform to it, its progression, and time-dependent molecular modifications. We aimed to develop an IR model by exogenous insulin administration. The effective dose of insulin glargine to generate hyperinsulinemia but without hypoglycemia was established. Then, two groups (control and insulin) of male Wistar rats of 100 g weight were formed. The selected dose (4 U/kg) was administered for 15, 30, 45, and 60 days. Zoometry, a glucose tolerance test, insulin response, IR, and the serum lipid profile were assessed. We evaluated insulin signaling, glycogenesis and lipogenesis, redox balance, and inflammation in the liver. Results showed an impairment of glucose tolerance, dyslipidemia, hyperinsulinemia, and peripheral and time-dependent selective IR. At the hepatic level, insulin signaling was impaired, resulting in reduced hepatic glycogen levels and triglyceride accumulation, an increase in the ROS level with MAPK-ERK1/2 response, and mild pro-oxidative microenvironmental sustained by MT, GSH, and GR activity. Hepatic IR coincides with additions in MAPK-p38, NF-κB, and zoometric changes. In conclusion, daily insulin glargine administration generated a progressive IR model. At the hepatic level, the IR was combined with oxidative conditions but without inflammation.

Hepatic IDH2 regulates glycolysis and gluconeogenesis

BACKGROUND AND AIMS

The liver plays a central role in controlling glucose and lipid metabolism. IDH2, a mitochondrial protein, controls TCA cycle flux. However, its role in regulating metabolism in obesity is still unclear. This study intends to investigate the impact of hepatic IDH2 expression on overnutrition-regulated glucose and lipid metabolism.

METHODS

Hepatic IDH2 was knocked-out in mice by the approach of CRISPR-Cas9. Mice were subjected to starvation and refeeding for hepatic glucose and lipid studies in vivo. Primary hepatocytes and mouse normal liver cell line, AML12 cells were used for experiments in vitro.

RESULTS

This study found that IDH2 protein levels were elevated in the livers of obese people and mice with high-fat diet consumption or hepatic steatosis. Liver IDH2-deletion mice (IDH2^LKO) were resistant to high-fat diet-induced body weight gain, with lower serum glucose and TG levels, increased insulin sensitivity, and higher FGF21 secretion, despite the higher TG content in the liver. Consistently, overexpression of IDH2 in hepatocytes promoted gluconeogenesis and enhanced glycogenesis. By performing mass spectrometry and proteomics analyses, we further demonstrated that IDH2-deficiency in hepatocytes accelerated ATP production by increasing forward TCA cycle flux, thus promoting glycolysis pathway and decreasing glycogen synthesis at refeeding state, and inhibiting hepatic gluconeogenesis, increasing β-oxidation during starvation. Moreover, experiments in vivo demonstrated that IDH2-knockout might not exacerbate hepatic inflammatory responses in the NASH model.

CONCLUSIONS

Elevated hepatic IDH2 under over-nutrition state contributes to elevated gluconeogenesis and glycogen synthesis. Inhibition of IDH2 in the liver could be a potential therapeutic target for obesity and diabetes.

The roles of dietary lipids and lipidomics in gut-brain axis in type 2 diabetes mellitus

Type 2 diabetes mellitus (T2DM), one of the main types of Noncommunicable diseases (NCDs), is a systemic inflammatory disease characterized by dysfunctional pancreatic β-cells and/or peripheral insulin resistance, resulting in impaired glucose and lipid metabolism. Genetic, metabolic, multiple lifestyle, and sociodemographic factors are known as related to high T2DM risk. Dietary lipids and lipid metabolism are significant metabolic modulators in T2DM and T2DM-related complications. Besides, accumulated evidence suggests that altered gut microbiota which plays an important role in the metabolic health of the host contributes significantly to T2DM involving impaired or improved glucose and lipid metabolism. At this point, dietary lipids may affect host physiology and health via interaction with the gut microbiota. Besides, increasing evidence in the literature suggests that lipidomics as novel parameters detected with holistic analytical techniques have important roles in the pathogenesis and progression of T2DM, through various mechanisms of action including gut-brain axis modulation. A better understanding of the roles of some nutrients and lipidomics in T2DM through gut microbiota interactions will help develop new strategies for the prevention and treatment of T2DM. However, this issue has not yet been entirely discussed in the literature. The present review provides up-to-date knowledge on the roles of dietary lipids and lipidomics in gut-brain axis in T2DM and some nutritional strategies in T2DM considering lipids- lipidomics and gut microbiota interactions are given.

The Liver and Glycogen: In Sickness and in Health

The liver is a major store of glycogen and is essential in maintaining systemic glucose homeostasis. In healthy individuals, glycogen synthesis and breakdown in the liver are tightly regulated. Abnormal glycogen metabolism results in prominent pathological changes in the liver, often manifesting as hepatic glycogenosis or glycogen inclusions. This can occur in genetic glycogen storage disease or acquired conditions with insulin dysregulation such as diabetes mellitus and non-alcoholic fatty liver disease or medication effects. Some primary hepatic tumors such as clear cell hepatocellular carcinoma also demonstrate excessive glycogen accumulation. This review provides an overview of the pathological manifestations and molecular mechanisms of liver diseases associated with abnormal glycogen accumulation.

Acacetin attenuates the pancreatic and hepatorenal dysfunction in type 2 diabetic rats induced by high-fat diet combined with streptozotocin

Acacetin is a natural flavonoid compound with multiple therapeutic potential in oxidative stress, inflammation, cancers, cardiovascular disease and infections. The present study aimed to detect the effect of acacetin on pancreatic and hepatorenal dysfunction in type 2 diabetic rats. The diabetic rats were induced by high-fat diet (HFD) followed by intraperitoneal injection of streptozotocin (STZ) at a dose of 45 mg/kg. Different doses of acacetin were orally administrated once a day for 8 weeks after the diabetic model was successfully established. The experimental results revealed that acacetin and acarbose displayed obvious attenuation in the levels of fasting blood glucose (FBG) and lipids compared to the untreated diabetic rats. In addition, the physiological function of liver and kidney was impaired in the persistent environment of hyperglycemia, while acacetin improved the damage of liver and kidney. Furthermore, hematoxylin-eosin (H&E) staining indicated that acacetin alleviated the pathological alterations of the pancreas, liver and kidney tissues. Besides, the increased levels of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), IL-8 and malondialdehyde (MDA) were recused by acacetin treatment, while the reduction of superoxide dismutase (SOD) levels were suppressed by acacetin treatment. In conclusion, the experimental results demonstrated that acacetin improved the lipids and glucose levels, and hepatorenal antioxidant capacity, as well as ameliorated hepatorenal dysfunction in type 2 diabetic rats, and the potential mechanism might be associated with its antioxidant and anti-inflammatory activities.

IGFBP5 antisense and short hairpin RNA (shRNA) constructs improve erectile function by inducing cavernosum angiogenesis in diabetic mice

BACKGROUND

The incidence of diabetic erectile dysfunction (ED) is rapidly increasing, and due to the severe angiopathy caused by diabetes, current drugs are ineffective at treating ED. Insulin-like growth factor-binding protein 5 (IGFBP5) promotes cell death and induces apoptosis in various cell types.

OBJECTIVES

To evaluate the effectiveness of IGFBP5 knockdown in improving erectile function in diabetic mice.

MATERIALS AND METHODS

Diabetes was induced by injecting streptozotocin (STZ) intraperitoneally into male 8-week-old C57BL/6 mice. Eight weeks after diabetes induction, mice were divided into four groups: a nondiabetic control group and three STZ-induced diabetic mice groups, which were administered intracavernous injections of phosphate buffered saline, scrambled control shRNA, or shRNA targeting mouse IGFBP5 (shIGFBP5) lentivirus particles. Two weeks later, we measured erectile function by electrically stimulating the bilateral cavernous nerve. To mimic diabetic angiopathy, primary cavernous endothelial cells (MCECs) from healthy mice were cultured and treated with glucose.

RESULTS

IGFBP5 expression in MCECs or cavernous tissues were significantly increased under diabetic conditions, and knockdown of IGFBP5 induced MCECs angiogenic activity under high-glucose conditions. STZ-induced diabetic mice had reduced erectile function, but shIGFBP5 treatment resulted in significant improvements (to 90% of the nondiabetic control group level). Furthermore, in diabetic mice, numbers of cavernous endothelial cells, pericytes, and neuronal cells were increased by shIGFBP5 treatment, which also increased eNOS Ser¹¹⁷⁷ phosphorylation, decreased permeability and apoptosis of cavernous endothelial cells. In addition, IGFBP5 was found to mediate the AKT, ERK, p38 signaling pathways.

DISCUSSION AND CONCLUSION

Knockdown of IGFBP5 improved erectile function in diabetic mice by promoting cell proliferation and reducing apoptosis and permeability. Local inhibition of IGFBP5 expression may provide a new treatment strategy for diabetic ED and other ischemic vascular or neurological diseases.

A systematic review on anti-diabetic plant essential oil compounds: Dietary sources, effects, molecular mechanisms, and safety

Type 2 diabetes mellitus (T2DM) is a multifaceted metabolic syndrome defined through the dysfunction of pancreatic β-cells driven by a confluence of genetic and environmental elements. Insulin resistance, mediated by interleukins and other inflammatory elements, is one of the key factors contributing to the progression of T2DM. Many essential oils derived from dietary plants are beneficial against various chronic diseases. We reviewed the anti-diabetic properties of dietary plant-derived essential oil compounds, with a focus on their molecular mechanisms by modulating specific signaling pathways and other critical inflammatory mediators involved in insulin resistance. High-quality literature published in the last 12 years, from 2010 to 2022, was collected from the Scopus, Web of Science, PubMed, and Embase databases using the search terms "dietary plants," "essential oils," "anti-diabetic," "insulin resistance," "antihyperglycemic," "T2DM," "anti-diabetic essential oils," and anti-diabetic mechanism." According to the results, the essential oil compounds, including cinnamaldehyde, carvacrol, zingerone, sclareol, zerumbone, myrtenol, thujone, geraniol, citral, eugenol, thymoquinone, thymol, citronellol, α-terpineol, and linalool have been demonstrated to contain strong anti-diabetic effects via modulating various signal transduction pathways linked to glucose metabolism. Additionally, in diabetes-related animal models, they can also considerably reduce the expression of TNF-α, IL-1β, IL-4, IL-6, iNOS, and COX-2. The main signaling molecules regulated by these compounds include AMPK, GLUT4, Caspase-3, PPARγ, PPARα, NF-κB, p-IκBα, MyD88, MCP-1, SREBP-1c, AGEs, RAGE, VEGF, Nrf2/HO-1, and SIRT-1. They can also significantly inhibit the generation of TBARS and MDA, reduce oxidative stress, increase insulin levels, adiponectin, and glycoprotein enzymes, boost antioxidant enzymes like SOD, CAT, and GPx, as well as reduce glutathione and vital glycolytic enzymes. Besides, they can significantly lower the levels of liver enzymes and lipid profile markers. Moreover, most essential oil compounds are generally safe based on animal studies. In conclusion, dietary plant-derived essential oil compounds have potential anti-diabetic effects by influencing different signaling pathways and molecular targets linked to glucose metabolism, and should be safe and beneficial against diabetes and related complications.

Phenolipid JE improves metabolic profile and inhibits gluconeogenesis via modulating AKT-mediated insulin signaling in STZ-induced diabetic mice

Phenolipids are characteristic phytochemicals of Syzygium genus. However, the antidiabetic potential and underlying molecular mechanism of these components are not fully elucidated. Herein, we studied the anti-diabetic effects of jambone E (JE), a phenolipid from S. cumini, with in vitro and in vivo models. Data from current study showed that JE enhanced glucose consumption and uptake, promoted glycogen synthesis, and suppressed gluconeogenesis in insulin resistant (IR)-HepG2 cells and primary mouse hepatocytes. JE also attenuated streptozotocin-induced hyperglycemia and hyperlipidemia in type 1 diabetic (T1D) mice. Eleven metabolites (e.g. trimethylamine n-oxide, 4-pyridoxic acid, phosphatidylinositol 39:4, phenaceturic acid, and hippuric acid) were identified as potential serum biomarkers for JE's antidiabetic effects by an untargeted metabolomics approach. The further molecular mechanistic study revealed that JE up-regulated phosphorylation levels of protein kinase B (AKT), glycogen synthase kinase 3 beta, and forkhead box O1 (FoxO1), promoted nuclear exclusion of FoxO1 whilst decreased gene expression levels of peroxisome proliferator-activated receptor gamma coactivator-1 alpha, phosphoenolpyruvate carboxykinase and glucose 6-phosphatase in IR-HepG2 cells and T1D mice. Our data suggested that JE might be a potent activator for AKT-mediated insulin signaling pathway, which was confirmed by the usage of AKT inhibitor and AKT-target siRNA interference, as well as the cellular thermal shift assay. Findings from the current study shed light on the anti-diabetic effects of phenolipids in the Syzygium species, which supports the use of medicinal plants in the Syzygium genus for potential pharmaceutical applications.

Hepatoprotective effects of gentisic acid through its anti-oxidant properties in nicotinamide-streptozotocin induced diabetic mice

Objectives

Type 2 diabetes mellitus (T2DM) is a common metabolic disorder that causes many complications. Liver failure is one of the complications of T2DM. Oxidative stress plays a major role in the development and progression of T2DM-induced liver injury. Gentisic acid (GA) is a metabolite of aspirin and also a phenolic compound found in natural sources that is a highly effective antioxidant and free radical scavenger. So, in this study, the potential preventive benefits of GA against liver damage induced by T2DM were explored.

Materials and Methods

This study was conducted on 24 adult male mice. T2DM was induced by intraperitoneal injection of a single dose of streptozotocin (at a dose of 65 mg/kg), 15 min after the injection of nicotinamide (at a dose of 120 mg/kg). The grouping was as follows: 1) Normal Control Group; 2) Diabetic Control Group; 3) Positive Control Group: received metformin (150 mg/kg body weight daily) through gavage; 4) Treatment Group: received GA at the dose of 100 mg/kg body weight daily through gavage. Treatments continued for two weeks.

Results

Two weeks of GA treatment in diabetic mice reduced fasting blood glucose, improved plasma levels of hepatic enzymes, and increased liver tissue antioxidant capacity. Histopathological examination revealed that GA administration reduced diabetes-induced liver damage. Furthermore, GA treatment led to the down-regulation of Kelch-like ECH-associated protein 1 (Keap1) and up-regulation of nuclear factor E2-related factor 2 (Nrf2).

Conclusion

The results of this study showed that GA exerts hepatoprotective effects in STZ-induced T2DM mice.

Feeding-induced hepatokines and crosstalk with multi-organ: A novel therapeutic target for Type 2 diabetes

Hyperglycemia, which can be caused by either an insulin deficit and/or insulin resistance, is the main symptom of Type 2 diabetes, a significant endocrine metabolic illness. Conventional medications, including insulin and oral antidiabetic medicines, can alleviate the signs of diabetes but cannot restore insulin release in a physiologically normal amount. The liver detects and reacts to shifts in the nutritional condition that occur under a wide variety of metabolic situations, making it an essential organ for maintaining energy homeostasis. It also performs a crucial function in glucolipid metabolism through the secretion of hepatokines. Emerging research shows that feeding induces hepatokines release, which regulates glucose and lipid metabolism. Notably, these feeding-induced hepatokines act on multiple organs to regulate glucolipotoxicity and thus influence the development of T2DM. In this review, we focus on describing how feeding-induced cross-talk between hepatokines, including Adropin, Manf, Leap2 and Pcsk9, and metabolic organs (e.g.brain, heart, pancreas, and adipose tissue) affects metabolic disorders, thus revealing a novel approach for both controlling and managing of Type 2 diabetes as a promising medication.

Excessive gluconeogenesis causes the hepatic insulin resistance paradox and its sequelae

Background

Hepatic insulin signaling suppresses gluconeogenesis but promotes de novo lipid synthesis. Paradoxically, hepatic insulin resistance (HIR) enhances both gluconeogenesis and de novo lipid synthesis. Elucidation of the etiology of this paradox, which participates in the pathogenesis of non-alcoholic fatty liver disease (NAFLD), cardiovascular disease, the metabolic syndrome and hepatocellular carcinoma, has not been fully achieved.

Scope of review

This article briefly outlines the previously proposed hypotheses on the etiology of the HIR paradox. It then discusses literature consistent with an alternative hypothesis that excessive gluconeogenesis, the direct effect of HIR, is responsible for the aberrant lipogenesis. The mechanisms involved therein are explained, involving de novo synthesis of fructose and uric acid, promotion of glutamine anaplerosis, and induction of glucagon resistance. Thus, gluconeogenesis via lipogenesis promotes hepatic steatosis, a component of NAFLD, and dyslipidemia. Gluconeogenesis-centred mechanisms for the progression of NAFLD from simple steatosis to non-alcoholic steatohepatitis (NASH) and fibrosis are suggested. That NAFLD often precedes and predicts type 2 diabetes is explained by the ability of lipogenesis to cushion against blood glucose dysregulation in the earlier stages of NAFLD.

Major conclusions

HIR-induced excessive gluconeogenesis is a major cause of the HIR paradox and its sequelae. Such involvement of gluconeogenesis in lipid synthesis rationalizes the fact that several types of antidiabetic drugs ameliorate NAFLD. Thus, dietary, lifestyle and pharmacological targeting of HIR and hepatic gluconeogenesis may be a most viable approach for the prevention and management of the HIR-associated network of diseases.

PAR2 promotes impaired glucose uptake and insulin resistance in NAFLD through GLUT2 and Akt interference

BACKGROUND AND AIMS

Insulin resistance and poor glycemic control are key drivers of the development of NAFLD and have recently been shown to be associated with fibrosis progression in NASH. However, the underlying mechanisms involving dysfunctional glucose metabolism and relationship with NAFLD/NASH progression remain poorly understood. We set out to determine whether protease-activated receptor 2 (PAR2), a sensor of extracellular inflammatory and coagulation proteases, links NAFLD and NASH with liver glucose metabolism.

APPROACH AND RESULTS

Here, we demonstrate that hepatic expression of PAR2 increases in patients and mice with diabetes and NAFLD/NASH. Mechanistic studies using whole-body and liver-specific PAR2-knockout mice reveal that hepatic PAR2 plays an unexpected role in suppressing glucose internalization, glycogen storage, and insulin signaling through a bifurcating Gq -dependent mechanism. PAR2 activation downregulates the major glucose transporter of liver, GLUT2, through Gq -MAPK-FoxA3 and inhibits insulin-Akt signaling through Gq -calcium-CaMKK2 pathways. Therapeutic dosing with a liver-homing pepducin, PZ-235, blocked PAR2-Gq signaling and afforded significant improvements in glycemic indices and HbA1c levels in severely diabetic mice.

CONCLUSIONS

This work provides evidence that PAR2 is a major regulator of liver glucose homeostasis and a potential target for the treatment of diabetes and NASH.

Obesity, but not glycemic control, predicts liver steatosis in children with type 1 diabetes

OBJECTIVE

Nonalcoholic fatty liver disease (NAFLD), the most common liver disease in children, is strongly associated with obesity and insulin resistance. Although type 1 diabetes (T1D) is characterized by insulin deficiency, increasing obesity rates among children with T1D is a major risk factor for NAFLD in this patient population. Predisposing factors for NAFLD in children with T1D are not known.

STUDY DESIGN

This is a cross-sectional study comparing children with T1D across the range of body mass index (BMI) to the BMI-matched obese group without T1D. Hepatic steatosis was semi-quantitatively measured via the vibration-controlled transient elastogram (VCTE) method. Linear regression analysis was performed to assess the relationship between controlled-attenuated parameter (CAP) scores and clinical parameters. Receiver-operator curve (ROC) analysis was used to evaluate the diagnostic performance of several clinical parameters against NAFLD status determined via CAP.

RESULTS

Two-thirds of subjects with obesity had CAP scores suggestive of NAFLD, while 16 % (n = 6) of T1D patients without obesity had elevated CAP. Obese subjects were different from non-obese subjects in many laboratory and clinical characteristics, regardless of T1D status. CAP score was significantly associated with BMI, HDL-Cholesterol (HDL-c), and HbA1c in all subjects as well as the T1D-only subgroup. Among subjects with obesity only, age, HDL-cand ALT were the most significant predictors. Diagnostic performance of BMI, HDL-c, and BMI/HDL ratio were in the good to the excellent range for predicting NAFLD among all subjects, while performance varied for T1D-only or obesity-only groups.

CONCLUSION

The clinical and imaging findings of children with T1D and obesity are comparable to non-diabetic children with a similar degree of obesity. Obesity is the major risk factor for NAFLD in pediatric T1D. BMI, HDL-c, and BMI/HDL ratio may be helpful markers to determine further workup for NAFLD in children with T1D, particularly those with obesity.

Potential health benefits of Nigella sativa on diabetes mellitus and its complications: A review from laboratory studies to clinical trials

This review aims to gather and summarize up-to-date information on the potential health benefits of Nigella sativa (NS) on diabetes mellitus (DM) and its complications from different animal models, clinical trials and in vitro studies. DM is one of the most prevalent metabolic disorders resulting from chronic hyperglycaemia due to problems in insulin secretion, insulin action or both. It affects people regardless of age, gender and race. The main consequence of DM development is the metabolic dysregulation of glucose homeostasis. Current treatments for DM include pharmacological therapy, insulin and diabetic therapy targeting β cells. Some of these therapeutic approaches are promising; however, their safety and effectiveness remain elusive. Since ancient times, medicinal plants have been used and proven effective against diseases. These plants are believed to be effective and benefit physiological and pathological processes, as they can be used to prevent, reduce or treat multiple diseases. Nigella sativa Linn. is an annual indigenous herbaceous plant belonging to Ranunculaceae, the buttercup family. NS exhibits multifactorial activities; it could ameliorate oxidative, inflammatory, apoptotic and insulinotropic effects and inhibit carbohydrate digestive enzymes. Thus, this review demonstrates the therapeutic potential of NS that could be used as a complement or adjuvant for the management of DM and its complications. However, future research should be able to replicate and fill in the gaps of the study conducted to introduce NS safely to patients with DM.

Dehydrocostus lactone ameliorates lipid accumulation, insulin resistance, and endoplasmic reticulum stress in palmitate-treated hepatocytes

Fatty liver disease is caused by lipid accumulation in the liver, insulin resistance (IR), reactive oxygen species (ROS), and endoplasmic reticulum (ER) stress. Dehydrocostus lactone (DHE) has anticancer, anti-inflammatory, and anti-ulcer effects. However, its effects on hepatic steatosis and IR remain unclear. In this study, we investigated whether DHE has antisteatotic effect on fatty liver in vitro. Hepatocytes HepG2 and SNU-449 cells were exposed to 0.25 mM palmitate (PA), and then antisteatotic effect was evaluated by treatment with 10 μM DHE. DHE treatment reduced lipid accumulation and lipogenesis factor protein levels, compared with PA-treated hepatocytes. DHE treatment also decreased gluconeogenesis marker expression and recovered IR in PA-treated hepatocytes, and promoted glucose uptake in PA-treated HepG2 cells. Additionally, the levels of ROS and ER stress factors in PA-treated HepG2 cells were reduced by DHE treatment, compared with PA-treated HepG2 cells. Overall, DHE decreased lipid accumulation and lipogenesis factors as well as recovered IR, gluconeogenesis, and glucose uptake by reducing ER stress and ROS levels in PA-treated hepatocytes. Thus, DHE is a potential antisteatotic agent.