Amelioration of streptozotocin-induced type 2 diabetes mellitus in Wistar rats by arachidonic acid

Effects of environmentally relevant concentrations of florfenicol on the glucose metabolism system, intestinal microbiome, and liver metabolome of zebrafish

Florfenicol, a widely used veterinary antibiotic, has now been frequently detected in various water environments and human urines, with high concentrations. Accordingly, the ecological risks and health hazards of florfenicol are attracting increasing attention. In recent years, antibiotic exposure has been implicated in the disruption of animal glucose metabolism. However, the specific effects of florfenicol on the glucose metabolism system and the underlying mechanisms are largely unknown. Herein, zebrafish as an animal model were exposed to environmentally relevant concentrations of florfenicol for 28 days. Using biochemical and molecular analyses, we found that exposure to florfenicol disturbed glucose homeostasis, as evidenced by the abnormal levels of blood glucose and hepatic/muscular glycogen, and the altered expression of genes involved in glycogenolysis, gluconeogenesis, glycogenesis, and glycolysis. Considering the efficient antibacterial activity of florfenicol and the crucial role of intestinal flora in host glucose metabolism, we then analyzed changes in the gut microbiome and its key metabolite short-chain fatty acids (SCFAs). Results indicated that exposure to florfenicol caused gut microbiota dysbiosis, inhibited the production of intestinal SCFAs, and ultimately affected the downstream signaling pathways of SCFA involved in glucose metabolism. Moreover, non-targeted metabolomics revealed that arachidonic acid and linoleic acid metabolic pathways may be associated with insulin sensitivity changes in florfenicol-exposed livers. Overall, this study highlighted a crucial aspect of the environmental risks of florfenicol to both non-target organisms and humans, and presented novel insights into the mechanistic elucidation of metabolic toxicity of antibiotics.

Guava polysaccharides attenuate high fat and STZ-induced hyperglycemia by regulating gut microbiota and arachidonic acid metabolism

This study investigated the hypoglycemic mechanism of guava polysaccharides (GP) through the gut microbiota (GM) and related metabolites. Our findings demonstrated that GP significantly mitigated high-fat diet- and streptozotocin-induced hyperglycemia, insulin resistance, hyperlipidemia, elevated alanine aminotransferase, high hepatic inflammation levels, and prevented pancreatic atrophy and hepatomegaly. Interestingly, the benefits of GP were attributed to alterations in the GM. GP decreased the ratio of Firmicutes to Bacteroidetes, significantly inhibiting deleterious bacteria, including Uncultured_f_Desulfovibrionaceae, Bilophila, and Desulfovibrio, while promoting the proliferation of probiotic Bifidobacterium and Bacteroides. In addition, GP promoted the generation of short-chain fatty acids. Notably, the arachidonic acid (AA) metabolism pathway was enriched in liver metabolites. GP significantly elevated hepatic AA and 15-hydroxyeicosatetraenoic acid, while reducing prostaglandin E2 and 5- and 12-hydroxyeicosatetraenoic acid. This modulation is accompanied by the downregulation of hepatic cyclooxygenase-1, 12-lipoxygenase, P38, and c-Jun N-terminal kinase mRNA expression, and the upregulation of cytochrome P4502J5 and insulin receptor substrate 1/2 mRNA expression. However, GP antibiotic treatment did not induce significant alterations in FBG and AA levels or gene expression. Overall, our findings suggest that the hypoglycemic effect of GP may be intricately linked to alterations in AA metabolism, which depends on the GM.

Unveiling the Pharmacological Mechanisms of Davidiin's Anti-Diabetic Efficacy in Streptozotocin-Treated Rats: A Comprehensive Analysis of Serum Metabolome

Background

Polygonum capitatum Buch.-Ham. ex D. Don (P. capitatum), a traditional herb used in Miao medicine, is renowned for its heart-clearing properties. Davidiin, the primary bioactive component (approximately 1%), has been used to treat various conditions, including diabetes. Given its wide range of effects and the diverse biomolecular pathways involved in diabetes, there is a crucial need to study how davidiin interacts with these pathways to better understand its anti-diabetic properties.

Materials and Methods

Diabetic rats were induced using a high-fat diet and streptozotocin (STZ) administered intraperitoneally at 35 mg/kg. Out of these, 24 rats with blood glucose levels ≥ 11.1 mmol/L and fasting blood glucose levels ≥ 7.0 mmol/L were selected for three experimental groups. These groups were then treated with either metformin (gavage, 140 mg/kg) or davidiin (gavage, 90 mg/kg) for four weeks. After the treatment period, we measured body weight, blood glucose levels, and conducted untargeted metabolic profiling using UPLC-QTOF-MS.

Results

Davidiin has been shown to effectively treat diabetes by reducing blood glucose levels from 30.2 ± 2.6 mmol/L to 25.1 ± 2.4 mmol/L (P < 0.05). This effect appears stronger than that of metformin, which lowered glucose levels to 26.5 ± 2.6 mmol/L. The primary outcomes of serum metabolomics are significant changes in lipid and lipid-like molecular profiles. Firstly, davidiin may affect phosphatide metabolism by increasing levels of phosphatidylinositol and sphingosine-1-phosphate. Secondly, davidiin could influence cholesterol metabolism by reducing levels of glycocholic acid and glycochenodeoxycholic acid. Lastly, davidiin might impact steroid hormone metabolism by increasing hepoxilin B3 levels and decreasing prostaglandins.

Conclusion

Our study demonstrates that davidiin modulates various lipid-related metabolic pathways to exert its anti-diabetic effects. These findings offer the first detailed metabolic profile of davidiin's action mechanism, contributing valuable insights to the field of Traditional Chinese Medicine in the context of diabetes treatment.

Citric Acid Promotes Immune Function by Modulating the Intestinal Barrier

Amidst increasing concern about antibiotic resistance resulting from the overuse of antibiotics, there is a growing interest in exploring alternative agents. One such agent is citric acid, an organic compound commonly used for various applications. Our research findings indicate that the inclusion of citric acid can have several beneficial effects on the tight junctions found in the mouse intestine. Firstly, the study suggests that citric acid may contribute to weight gain by stimulating the growth of intestinal epithelial cells (IE-6). Citric acid enhances the small intestinal villus-crypt ratio in mice, thereby promoting intestinal structural morphology. Additionally, citric acid has been found to increase the population of beneficial intestinal microorganisms, including Bifidobacterium and Lactobacillus. It also promotes the expression of important protein genes such as occludin, ZO-1, and claudin-1, which play crucial roles in maintaining the integrity of the tight junction barrier in the intestines. Furthermore, in infected IEC-6 cells with H9N2 avian influenza virus, citric acid augmented the expression of genes closely associated with the influenza virus infection. Moreover, it reduces the inflammatory response caused by the viral infection and thwarted influenza virus replication. These findings suggest that citric acid fortifies the intestinal tight junction barrier, inhibits the replication of influenza viruses targeting the intestinal tract, and boosts intestinal immune function.

A review on the relationship between Arachidonic acid 15-Lipoxygenase (ALOX15) and diabetes mellitus

Arachidonic acid 15-lipoxygenase (ALOX15), as one of the lipoxygenase family, is mainly responsible for catalyzing the oxidation of various fatty acids to produce a variety of lipid components, contributing to the pathophysiological processes of various immune and inflammatory diseases. Studies have shown that ALOX15 and its related products are widely distributed in human tissues and related to multiple diseases such as liver, cardiovascular, cerebrovascular diseases, diabetes mellitus and other diseases. Diabetes mellitus (DM), the disease studied in this article, is a metabolic disease characterized by a chronic increase in blood glucose levels, which is significantly related to inflammation, oxidative stress, ferroptosis and other mechanisms, and it has a high incidence in the population, accompanied by a variety of complications. Figuring out how ALOX15 is involved in DM is critical to understanding its role in diseases. Therefore, ALOX15 inhibitors or combination therapy containing inhibitors may deliver a novel research direction for the treatment of DM and its complications. This article aims to review the biological effect and the possible function of ALOX15 in the pathogenesis of DM.

Therapeutic Potentials of Microalgae and Their Bioactive Compounds on Diabetes Mellitus

Diabetes mellitus is a metabolic disorder characterized by hyperglycemia due to impaired insulin secretion, insulin resistance, or both. Oxidative stress and chronic low-grade inflammation play crucial roles in the pathophysiology of diabetes mellitus. There has been a growing interest in applying natural products to improve metabolic derangements without the side effects of anti-diabetic drugs. Microalgae biomass or extract and their bioactive compounds have been applied as nutraceuticals or additives in food products and health supplements. Several studies have demonstrated the therapeutic effects of microalgae and their bioactive compounds in improving insulin sensitivity attributed to their antioxidant, anti-inflammatory, and pancreatic β-cell protective properties. However, a review summarizing the progression in this topic is lacking despite the increasing number of studies reporting their anti-diabetic potential. In this review, we gathered the findings from in vitro, in vivo, and human studies to discuss the effects of microalgae and their bioactive compounds on diabetes mellitus and the mechanisms involved. Additionally, we discuss the limitations and future perspectives of developing microalgae-based compounds as a health supplement for diabetes mellitus. In conclusion, microalgae-based supplementation has the potential to improve diabetes mellitus and be applied in more clinical studies in the future.

D-Pinitol Content and Antioxidant and Antidiabetic Activities of Five Bougainvillea spectabilis Willd. Cultivars

Diabetes mellitus is a major challenge for global health, and Bougainvillea spectabilis Willd. (B. spectabilis) is a widely used herbal remedy with diverse cultivars traditionally used for diabetes treatment. However, the comparative efficacy of these cultivars remains ambiguous. This study aimed to evaluate the D-pinitol content and DPPH radical-scavenging activity of methanolic leaves extracts of five B. spectabilis cultivars. Furthermore, the effects of these cultivars on various parameters, including blood glucose levels, oxidative stress markers, inflammatory cytokines, lipid profiles, liver enzymes, renal function markers, and histopathological changes, were assessed in STZ-induced diabetic rats after one month of oral daily treatment. All tested cultivars demonstrated significant improvements in the measured parameters, albeit to varying extents. Notably, the LOE cultivar, distinguished by its orange bracts, exhibited the highest efficacy, surpassing the effectiveness of glibenclamide, an antidiabetic medication, and displayed the highest concentration of D-pinitol. These findings underscore the importance of carefully selecting the appropriate B. spectabilis cultivar to maximize the antidiabetic efficacy, with a particular emphasis on the correlation between antidiabetic activity and D-pinitol concentrations.

Studying and Analyzing Humane Endpoints in the Fructose-Fed and Streptozotocin-Injected Rat Model of Diabetes

This work aimed to define a humane endpoint scoring system able to objectively identify signs of animal suffering in a rat model of type 2 diabetes. Sprague-Dawley male rats were divided into control and induced group. The induced animals drink a 10% fructose solution for 14 days. Then, received an administration of streptozotocin (40 mg/kg). Animals' body weight, water and food consumption were recorded weekly. To evaluate animal welfare, a score sheet with 14 parameters was employed. Blood glucose levels were measured at three time points. After seven weeks of initiating the protocol, the rats were euthanized. The induced animals showed weight loss, polyuria, polyphagia, and polydipsia. According to our humane endpoints table, changes in animal welfare became noticeable after the STZ administration. None of the animals hit the critical score limit (four). Data showed that the most effective parameters to assess welfare in this type 2 diabetes rat induction model were dehydration, grooming, posture, abdominal visualization, and stool appearance. The glycemia was significantly higher in the induced group when compared to the controls (p < 0.01). Induced animals' murinometric and nutritional parameters were significantly lower than the controls (p < 0.01). Our findings suggest that in this rat model of type 2 diabetes with STZ-induced following fructose consumption, our list of humane endpoints is suitable for monitoring the animals' welfare.

Fatty acids of type 2 diabetic serum decrease the stemness properties of human adipose-derived mesenchymal stem cells

In type 2 diabetes, dyslipidemia and increased serum free fatty acids (FFAs) exacerbate the development of the disease through a negative effect on insulin secretion. Adipose-derived mesenchymal stem cells (AdMSCs) play a key role in regenerative medicine, and these cells can potentially be applied as novel therapeutic resources in the treatment of diabetes. In this study, AdMSCs were treated with diabetic or nondiabetic serum FFAs isolated from women of menopausal age. Serum FFAs were analyzed using gas-liquid chromatography. The expression level of the stemness markers CD49e and CD90 and the Wnt signaling target genes Axin-2 and c-Myc were evaluated using real-time PCR. The proliferation rate and colony formation were also assessed using a BrdU assay and crystal violet staining, respectively. The level of glutathione was assessed using cell fluorescence staining. Compared to nondiabetic serum, diabetic serum contained a higher percentage of oleate (1.5-fold, p < 0.01). In comparison with nondiabetic FFAs, diabetic FFAs demonstrated decreasing effects on the expression of CD90 (-51%, p < 0.001) and c-Myc (-48%, p < 0.05), and proliferation rate (-35%, p < 0.001), colony formation capacity (-50%, p < 0.01), and GSH levels (-62%, p < 0.05). The negative effect of the FFAs of diabetic serum on the stemness characteristics may impair the regenerative capabilities of AdMSCs.

Pro- and anti-inflammatory bioactive lipids imbalance contributes to the pathobiology of autoimmune diseases

Autoimmune diseases are driven by T_H17 cells that secrete pro-inflammatory cytokines, especially IL-17. Under normal physiological conditions, autoreactive T cells are suppressed by TGF-β and IL-10 secreted by microglia and dendritic cells. When this balance is upset due to injury, infection and other causes, leukocyte recruitment and macrophage activation occurs resulting in secretion of pro-inflammatory IL-6, TNF-α, IL-17 and PGE2, LTs (leukotrienes) accompanied by a deficiency of anti-inflammatory LXA4, resolvins, protecting, and maresins. PGE2 facilitates T_H1 cell differentiation and promotes immune-mediated inflammation through T_H17 expansion. There is evidence to suggest that autoimmune diseases can be suppressed by anti-inflammatory bioactive lipids LXA4, resolvins, protecting, and maresins. These results imply that systemic and/or local application of LXA4, resolvins, protecting, and maresins and administration of their precursors AA/EPA/DHA could form a potential therapeutic approach in the prevention and treatment of autoimmune diseases.

Structural characterization and preventive effect on non-alcoholic fatty liver disease of oligosaccharides from Bletilla striata

In this study, Bletilla striata polysaccharides were degraded into oligosaccharides. The structural features were analyzed by HPLC, HPLC-MS, FT-IR, and NMR spectroscopy. The results indicated that Bletilla striata oligosaccharides (BOs) were composed of mannose and glucose with a molar ratio of 5.2 : 1, and the main backbones of BOs contained (1→4)-linked-α-D-Man, (1→2)-linked-α-D-Man, and (1→2)-linked-α-D-Glc. By using a high-fat diet (HFD)-induced mouse model, we demonstrated that BOs had an improving effect on non-alcoholic fatty liver disease (NAFLD). Using the metabolomics assay, we found that BOs significantly regulated the hepatic metabolism of fatty acids, arachidonic acid, and other related metabolites in HFD-fed mice, accompanied by the reduction of lipid accumulation and fibrosis in liver tissues. In summary, BOs displayed high potential for the treatment of NAFLD as a functional food.

Possible roles of anti-type II collagen antibody and innate immunity in the development and progression of diabetic retinopathy

The pathogenesis of both diabetic retinopathy (DR) and rheumatoid arthritis (RA) has recently been considered to involve autoimmunity. Serum and synovial fluid levels of anti-type II collagen antibodies increase early after the onset of RA, thus inducing immune responses and subsequent hydrarthrosis and angiogenesis, which resemble diabetic macular edema and proliferative DR (PDR), respectively. We previously reported that DR is also associated with increased serum levels of anti-type II collagen antibodies. Retinal hypoxia in DR may induce pericytes to express type II collagen, resulting in autoantibody production against type II collagen. As the result of blood-retinal barrier disruption, anti-type II collagen antibodies in the serum come into contact with type II collagen around the retinal vessels. A continued loss of pericytes and type II collagen around the retinal vessels may result in a shift of the immune reaction site from the retina to the vitreous. It has been reported that anti-inflammatory M2 macrophages increased in the vitreous of PDR patients, accompanied by the activation of the NOD-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome, a key regulator of innate immunity. M2 macrophages promote angiogenesis and fibrosis, which might be exacerbated and prolonged by dysregulated innate immunity.

Serum Metabolomics Analysis for Biomarkers of Lactobacillus plantarum FRT4 in High-Fat Diet-Induced Obese Mice

Lactobacillus plantarum is considered a potential probiotic supplementation for treating obesity. However, the underlying molecular mechanism is poorly understood. Our previous study displayed that L. plantarum FRT4 alleviated obesity in mice fed a high-fat diet (HFD) through ameliorating the HFD-induced gut microbiota dysbiosis. To explore the roles of FRT4 in obesity prevention, in this study, we investigated changes in serum metabolomic phenotype by ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UHPLC-QTOF/MS) and analyzed the pathway of HFD-fed Kunming female mice orally administered with FRT4 for eight weeks. Using orthogonal partial least squares discriminant analysis (OPLS-DA), metabolite patterns with significant changes were observed. 55 metabolites including phosphatidylcholine, lysophophatidylcholine, sphingomyelin, serotonin, indole-3-methyl aceta, indole-3-carbinol, indole-5,6-quino, 11,12-DHET, prostaglandin B2, leukotriene B4, and 3-hydroxybenzoic acid were identified as potential biomarkers associated with obesity, which were mainly involving in glycerophospholipid metabolism, tryptophan metabolism, and arachidonic acid metabolism. Perturbations of 14 biomarkers could be regulated by FRT4 intervention. These metabolites may serve as valuable biomarkers to understand the mechanisms by which intake of diets containing FRT4 contributes to the treatment or prevention of obesity. Thus, FRT4 can be a promising dietary supplement for the prevention of HFD-induced obesity.

Essential Fatty Acids and Their Metabolites in the Pathobiology of Inflammation and Its Resolution

Arachidonic acid (AA) metabolism is critical in the initiation and resolution of inflammation. Prostaglandin E2 (PGE2) and leukotriene B4/D4/E4 (LTB4/LD4/LTE4), derived from AA, are involved in the initiation of inflammation and regulation of immune response, hematopoiesis, and M1 (pro-inflammatory) macrophage facilitation. Paradoxically, PGE2 suppresses interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) production and triggers the production of lipoxin A4 (LXA4) from AA to initiate inflammation resolution process and augment regeneration of tissues. LXA4 suppresses PGE2 and LTs' synthesis and action and facilitates M2 macrophage generation to resolve inflammation. AA inactivates enveloped viruses including SARS-CoV-2. Macrophages, NK cells, T cells, and other immunocytes release AA and other bioactive lipids to produce their anti-microbial actions. AA, PGE2, and LXA4 have cytoprotective actions, regulate nitric oxide generation, and are critical to maintain cell shape and control cell motility and phagocytosis, and inflammation, immunity, and anti-microbial actions. Hence, it is proposed that AA plays a crucial role in the pathobiology of ischemia/reperfusion injury, sepsis, COVID-19, and other critical illnesses, implying that its (AA) administration may be of significant benefit in the prevention and amelioration of these diseases.

Effect of Metabolite Levels on Type 2 Diabetes Mellitus and Glycemic Traits: A Mendelian Randomization Study

OBJECTIVE

To assess the causal associations of plasma levels of metabolites with type 2 diabetes mellitus (T2DM) and glycemic traits.

METHODS

Two-sample mendelian randomization (MR) was conducted to assess the causal associations. Genetic variants strongly associated with metabolites at genome-wide significance level (P < 5 × 10-8) were selected from public genome-wide association studies, and single-nucleotide polymorphisms of outcomes were obtained from the Diabetes Genetics Replication and Meta-analysis consortium for T2DM and from the Meta-Analyses of Glucose and Insulin-related Traits Consortium for fasting glucose, insulin, and glycated hemoglobin (HbA1c). The Wald ratio and inverse-variance weighted methods were used for analyses, and MR-Egger was used for sensitivity analysis.

RESULTS

The β estimates per 1-SD increase of arachidonic acid (AA) level was 0.16 (95% CI, 0.078-0.242; P < 0.001). Genetic predisposition to higher plasma AA levels were associated with higher fasting glucose levels (β 0.10 [95% CI, 0.064-0.134], P < 0.001), higher HbA1c levels (β 0.04 [95% CI, 0.027-0.061]), and lower fasting insulin levels (β -0.025 [95% CI, -0.047 to -0.002], P = 0.033). Besides, 2-hydroxybutyric acid (2-HBA) might have a positive causal effect on glycemic traits.

CONCLUSIONS

Our findings suggest that AA and 2-HBA may have causal associations on T2DM and glycemic traits. This is beneficial for clarifying the pathogenesis of T2DM, which would be valuable for early identification and prevention for T2DM.

Vitamin D Combined with Pioglitazone Mitigates Type-2 Diabetes-induced Hepatic Injury Through Targeting Inflammation, Apoptosis, and Oxidative Stress

Inflammation is a major pathophysiological factor in development of type-2 diabetes mellitus (T2DM). Vitamin D (VITD) plays an imperative role in modulation of several inflammatory responses. The current study aimed to investigate the possible beneficial effects of coadministration of VITD with pioglitazone (PIO), a PPAR-γ agonist, in fructose/streptozotocin (F/STZ) T2DM model in male Wistar rats. T2DM was induced by maintaining rats on 10% (w/v) fructose in drinking water for 9 weeks with an intraperitoneal injection of sub-diabetogenic dose of STZ (35 mg/kg) by the end of the fourth week. One week after STZ injection, PIO (10 mg/kg/day) alone or with VITD (500 IU/kg/day) was administered orally to diabetic rats till the end of the experiment. Blood samples were collected, livers were homogenized to determine biochemical parameters, and samples of livers were fixed in 10% formalin in saline for histological examination. Administration of PIO alone improved diabetes-induced inflammatory and oxidative states besides controlling hyperglycemia and decreasing apoptosis. Coadministration of VIT D with PIO promoted additional improvement in glycemic and lipid profiles, provided further control on diabetic-induced hepatic inflammation evident by downregulating TLR2, TLR4, and IKK-β while upregulating IκB-α expression and reducing inflammatory cytokines namely; NF-κB, TNF-α, IL-6, and IL-1β, decreasing apoptosis and oxidative stress by hampering caspase-3 and MDA contents, respectively, and improved liver histology than PIO alone. These beneficial effects of VIT D may expand its use by diabetics combined with antidiabetic drugs due to its anti-inflammatory, antioxidant, and antiapoptotic properties.

The stability of the metabolic turnover of arachidonic acid in human unruptured intracranial aneurysmal walls is sustained

OBJECTIVE

Intracranial aneurysm (IA) is considered a chronic inflammatory condition that affects intracranial arteries. Cyclooxygenase 2 (COX2) and prostaglandin E2 (PGE2) are considered potential targets of specific medical treatment for IAs. Previous studies have reported the elevated COX2 expression in the IA wall. However, not much has been studied about the upstream regulation of COX2 and PGE2, and the metabolism of arachidonic acid (AA) in human IAs. In this study, we aimed to elucidate the distribution of fatty acids in human IA walls for the first time.

METHODS

Samples from 6 ruptured and 5 unruptured human IAs were surgically resected after the aneurysmal clipping and analyzed using desorption electrospray ionization imaging mass spectrometry.

RESULTS

AA and AA-containing phospholipids were not detected in the unruptured IA walls. On the contrast, significantly larger amounts of AA and AA-containing phospholipids were detected in the ruptured IA walls compared to unruptured IA walls.

CONCLUSIONS

This study showed for the first time that AA was not detected in unruptured human IA walls. Our findings suggest that the stability of the turnover of AA in human unruptured IA walls is sustained. In contrast, this study showed that larger amounts of AA and AA-containing phospholipids were detected in the ruptured IA walls. More cases and further analysis are necessary to interpret our present results.

Aqueous Blackcurrant Extract Improves Insulin Sensitivity and Secretion and Modulates the Gut Microbiome in Non-Obese Type 2 Diabetic Rats

This study was undertaken to determine whether aqueous blackcurrant extracts (BC) improve glucose metabolism and gut microbiomes in non-obese type 2 diabetic animals fed a high-fat diet and to identify the mechanism involved. Partially pancreatectomized male Sprague–Dawley rats were provided a high-fat diet containing 0% (control), 0.2% (L-BC; low dosage), 0.6% (M-BC; medium dosage), and 1.8% (H-BC; high dosage) blackcurrant extracts; 0.2% metformin (positive-C); plus 1.8%, 1.6%, 1.2%, 0%, and 1.6% dextrin, specifically indigestible dextrin, daily for 8 weeks. Daily blackcurrant extract intakes were equivalent to 100, 300, and 900 mg/kg body weight (bw). After a 2 g glucose or maltose/kg bw challenge, serum glucose and insulin concentrations during peak and final states were obviously lower in the M-BC and H-BC groups than in the control group (p < 0.05). Intraperitoneal insulin tolerance testing showed that M-BC and H-BC improved insulin resistance. Hepatic triglyceride deposition, TNF-α expression, and malondialdehyde contents were lower in the M-BC and H-BC groups than in the control group. Improvements in insulin resistance in the M-BC and H-BC groups were associated with reduced inflammation and oxidative stress (p < 0.05). Hyperglycemic clamp testing showed that insulin secretion capacity increased in the acute phase (2 to 10 min) in the M-BC and H-BC groups and that insulin sensitivity in the hyperglycemic state was greater in these groups than in the control group (p < 0.05). Pancreatic β-cell mass was greater in the M-BC, H-BC, and positive-C groups than in the control group. Furthermore, β-cell proliferation appeared to be elevated and apoptosis was suppressed in these three groups (p < 0.05). Serum propionate and butyrate concentrations were higher in the M-BC and H-BC groups than in the control group. BC dose-dependently increased α-diversity of the gut microbiota and predicted the enhancement of oxidative phosphorylation-related microbiome genes and downregulation of carbohydrate digestion and absorption-related genes, as determined by PICRUSt2 analysis. In conclusion, BC enhanced insulin sensitivity and glucose-stimulated insulin secretion, which improved glucose homeostasis, and these improvements were associated with an incremental increase of the α-diversity of gut microbiota and suppressed inflammation and oxidative stress.

Metabolism pathways of arachidonic acids: mechanisms and potential therapeutic targets

The arachidonic acid (AA) pathway plays a key role in cardiovascular biology, carcinogenesis, and many inflammatory diseases, such as asthma, arthritis, etc. Esterified AA on the inner surface of the cell membrane is hydrolyzed to its free form by phospholipase A2 (PLA2), which is in turn further metabolized by cyclooxygenases (COXs) and lipoxygenases (LOXs) and cytochrome P450 (CYP) enzymes to a spectrum of bioactive mediators that includes prostanoids, leukotrienes (LTs), epoxyeicosatrienoic acids (EETs), dihydroxyeicosatetraenoic acid (diHETEs), eicosatetraenoic acids (ETEs), and lipoxins (LXs). Many of the latter mediators are considered to be novel preventive and therapeutic targets for cardiovascular diseases (CVD), cancers, and inflammatory diseases. This review sets out to summarize the physiological and pathophysiological importance of the AA metabolizing pathways and outline the molecular mechanisms underlying the actions of AA related to its three main metabolic pathways in CVD and cancer progression will provide valuable insight for developing new therapeutic drugs for CVD and anti-cancer agents such as inhibitors of EETs or 2J2. Thus, we herein present a synopsis of AA metabolism in human health, cardiovascular and cancer biology, and the signaling pathways involved in these processes. To explore the role of the AA metabolism and potential therapies, we also introduce the current newly clinical studies targeting AA metabolisms in the different disease conditions.

Resolvin D1 Decreases Severity of Streptozotocin-Induced Type 1 Diabetes Mellitus by Enhancing BDNF Levels, Reducing Oxidative Stress, and Suppressing Inflammation

Type 1 diabetes mellitus is an autoimmune disease characterized by increased production of pro-inflammatory cytokines secreted by infiltrating macrophages and T cells that destroy pancreatic β cells in a free radical-dependent manner that causes decrease or absence of insulin secretion and consequent hyperglycemia. Hence, suppression of pro-inflammatory cytokines and oxidative stress may ameliorate or decrease the severity of diabetes mellitus. To investigate the effect and mechanism(s) of action of RVD1, an anti-inflammatory metabolite derived from docosahexaenoic acid (DHA), on STZ-induced type 1 DM in male Wistar rats, type 1 diabetes was induced by single intraperitoneal (i.p) streptozotocin (STZ-65 mg/kg) injection. RVD1 (60 ng/mL, given intraperitoneally) was administered from day 1 along with STZ for five consecutive days. Plasma glucose, IL-6, TNF-α, BDNF (brain-derived neurotrophic factor that has anti-diabetic actions), LXA4 (lipoxin A4), and RVD1 levels and BDNF concentrations in the pancreas, liver, and brain tissues were measured. Apoptotic (Bcl2/Bax), inflammatory (COX-1/COX-2/Nf-κb/iNOS/PPAR-γ) genes and downstream insulin signaling proteins (Gsk-3β/Foxo1) were measured in the pancreatic tissue along with concentrations of various antioxidants and lipid peroxides. RVD1 decreased severity of STZ-induced type 1 DM by restoring altered plasma levels of TNF-α, IL-6, and BDNF (p < 0.001); expression of pancreatic COX-1/COX-2/PPAR-γ genes and downstream insulin signaling proteins (Gsk-3β/Foxo1) and the concentrations of antioxidants and lipid peroxides to near normal. RVD1 treatment restored expression of Bcl2/Pdx genes, plasma LXA4 (p < 0.001) and RVD1 levels and increased brain, pancreatic, intestine, and liver BDNF levels to near normal. The results of the present study suggest that RVD1 can prevent STZ-induced type 1 diabetes by its anti-apoptotic, anti-inflammatory, and antioxidant actions and by activating the Pdx gene that is needed for pancreatic β cell proliferation.

Pro-resolving lipid mediators: regulators of inflammation, metabolism and kidney function

Obesity, diabetes mellitus, hypertension and cardiovascular disease are risk factors for chronic kidney disease (CKD) and kidney failure. Chronic, low-grade inflammation is recognized as a major pathogenic mechanism that underlies the association between CKD and obesity, impaired glucose tolerance, insulin resistance and diabetes, through interaction between resident and/or circulating immune cells with parenchymal cells. Thus, considerable interest exists in approaches that target inflammation as a strategy to manage CKD. The initial phase of the inflammatory response to injury or metabolic dysfunction reflects the release of pro-inflammatory mediators including peptides, lipids and cytokines, and the recruitment of leukocytes. In self-limiting inflammation, the evolving inflammatory response is coupled to distinct processes that promote the resolution of inflammation and restore homeostasis. The discovery of endogenously generated lipid mediators - specialized pro-resolving lipid mediators and branched fatty acid esters of hydroxy fatty acids - which promote the resolution of inflammation and attenuate the microvascular and macrovascular complications of obesity and diabetes mellitus highlights novel opportunities for potential therapeutic intervention through the targeting of pro-resolution, rather than anti-inflammatory pathways.

Bioactive Lipids in COVID-19-Further Evidence

Previously, I suggested that arachidonic acid (AA, 20:4 n-6) and similar bioactive lipids (BALs) inactivate SARS-CoV-2 and thus, may be of benefit in the prevention and treatment of COVID-19. This proposal is supported by the observation that (i) macrophages and T cells (including NK cells, cytotoxic killer cells and other immunocytes) release AA and other BALs especially in the lungs to inactivate various microbes; (ii) pro-inflammatory metabolites prostaglandin E2 (PGE2) and leukotrienes (LTs) and anti-inflammatory lipoxin A4 (LXA4) derived from AA (similarly, resolvins, protectins and maresins derived from eicosapentaenoic acid: EPA and docosahexaenoic acid: DHA) facilitate the generation of M1 (pro-inflammatory) and M2 (anti-inflammatory) macrophages respectively; (iii) AA, PGE2, LXA4 and other BALs inhibit interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) synthesis; (iv) mesenchymal stem cells (MSCs) that are of benefit in COVID-19 elaborate LXA4 to bring about their beneficial actions and (v) subjects with insulin resistance, obesity, type 2 diabetes mellitus, hypertension, coronary heart disease and the elderly have significantly low plasma concentrations of AA and LXA4 that may render them more susceptible to SARS-CoV-2 infection and cytokine storm that is associated with increased mortality seen in COVID-19. Statins, colchicine, and corticosteroids that appear to be of benefit in COVID-19 can influence BALs metabolism. AA, and other BALs influence cell membrane fluidity and thus, regulate ACE-2 (angiotensin converting enzyme-2) receptors (the ligand through which SARS-CoV2 enters the cell) receptors. These observations lend support to the contention that administration of BALs especially, AA could be of significant benefit in prevention and management of COVI-19 and other enveloped viruses.

Based on Network Pharmacology Tools to Investigate the Molecular Mechanism of Cordyceps sinensis on the Treatment of Diabetic Nephropathy

BACKGROUND

Diabetic nephropathy (DN) is one of the most common complications of diabetes mellitus and is a major cause of end-stage kidney disease. Cordyceps sinensis (Cordyceps, Dong Chong Xia Cao) is a widely applied ingredient for treating patients with DN in China, while the molecular mechanisms remain unclear. This study is aimed at revealing the therapeutic mechanisms of Cordyceps in DN by undertaking a network pharmacology analysis.

MATERIALS AND METHODS

In this study, active ingredients and associated target proteins of Cordyceps sinensis were obtained via Traditional Chinese Medicine Systems Pharmacology Database (TCMSP) and Swiss Target Prediction platform, then reconfirmed by using PubChem databases. The collection of DN-related target genes was based on DisGeNET and GeneCards databases. A DN-Cordyceps common target interaction network was carried out via the STRING database, and the results were integrated and visualized by utilizing Cytoscape software. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were performed to determine the molecular mechanisms and therapeutic effects of Cordyceps on the treatment of DN.

RESULTS

Seven active ingredients were screened from Cordyceps, 293 putative target genes were identified, and 85 overlapping targets matched with DN were considered potential therapeutic targets, such as TNF, MAPK1, EGFR, ACE, and CASP3. The results of GO and KEGG analyses revealed that hub targets mainly participated in the AGE-RAGE signaling pathway in diabetic complications, TNF signaling pathway, PI3K-Akt signaling pathway, and IL-17 signaling pathway. These targets were correlated with inflammatory response, apoptosis, oxidative stress, insulin resistance, and other biological processes.

CONCLUSIONS

Our study showed that Cordyceps is characterized as multicomponent, multitarget, and multichannel. Cordyceps may play a crucial role in the treatment of DN by targeting TNF, MAPK1, EGFR, ACE, and CASP3 signaling and involved in the inflammatory response, apoptosis, oxidative stress, and insulin resistance.

Anti-diabetic, diabetic neuropathy protective action and mechanism of action involving oxidative pathway of chlorogenic acid isolated from Selinum vaginatum roots in rats

Phytopharmaceuticals have always reported vital roles in the field of medicine hence the need to investigate safe and efficient drugs for treating metabolic disorders is very significant. Roots of Selinum vaginatum have therapeutic benefits and are widely used by the people of the Rohtang region for treating diabetes and its associated complications. The present study focusses on the isolation of the bioactive from the S. vaginatum roots for estimating acute toxicity studies, anti-diabetic and diabetic neuropathy protective action along with the mechanism of action in STZ induced Wistar rats. The Selinum vaginatum roots were collected from the Rohtang region, Himalayas. Chlorogenic acid was isolated and underwent identification by UV, HPLC, ¹H NMR, C13 NMR, Mass, and FTIR spectroscopy methods. Chlorogenic acid was dosed at 10 and 20 mg/kg to observe the effects on experimentally induced diabetes and with time generated diabetic neuropathic complications. Biomarkers TNF-α, superoxide dismutase, nitrosative stress, lipid peroxide profile, and membrane-bound inorganic phosphate were analyzed. Histopathological evaluation of the liver and sciatic nerve was performed for all groups. Parameters like blood glucose levels, body weight, food intake, Thermal Hyperalgesia, Writhing, Cold Hyperalgesia Responses, Mechanical hyperalgesia, Grip Strength, Spontaneous Locomotor (Exploratory) Test, Neuromuscular Coordination tests, and lipid profile analysis showcased the anti-diabetic and diabetic neuropathy protective action of the drug. Inflammation, degradation, and necrosis were found to be reduced in the liver and sciatic nerve cells of treated groups. All the biomarkers used to analyze the oxidative pathway were significantly replenished indicates that chlorogenic acid produces these effects through this pathway.

High-Throughput Metabolomics Method for Discovering Metabolic Biomarkers and Pathways to Reveal Effects and Molecular Mechanism of Ethanol Extract From Epimedium Against Osteoporosis

Metabolomics is an effective strategy to explore the molecular mechanism of herbal medicine. Epimedium, a traditional Chinese herb from the Epimedium brevicornu Maxim., has a therapeutic effect on osteoporosis (OP), however the molecular mechanism of the anti-OP effect is uncle\ar. Therefore, we investigated the pharmacological effect and action mechanism of ethanol extract of epimedium (Ext-epi) onOP rat model. The serum of OP rats was analyzed utilized UPLC-Q-TOF/MS metabolomics, and the potential biomarkers were screened and identified using multivariate data analysis systems and network databases. To further appraise the influence of Ext-epi on biological markers and metabolic pathways, and reveal the potential mechanism of Ext-epi on OP treatment. The results showed that 46 potential biomarkers were screened out and after intervention with Ext-epi extracts solution, 16 potential biomarkers were significantly recalled. Further pathway experiments showed that key pathway analysis include sarachidonic acid metabolism, glycerolphospholipid metabolism as potential targets which is related with the efficacy of Ext-epi protect against OP. These results explain the correlation between metabolites and molecular mechanisms, which is of great significance for understanding the intervention of Ext-epi on OP. In short, based on UPLC-Q-TOF/MS metabolomics may provide effective strategies for understanding the pathogenesis of diseases and evaluating the intervention effect of natural products.

Bioactive Lipids as Mediators of the Beneficial Action(s) of Mesenchymal Stem Cells in COVID-19

It is proposed that the beneficial action of mesenchymal stem cells (MSCs) in COVID-19 and other inflammatory diseases could be attributed to their ability to secrete bioactive lipids (BALs) such as prostaglandin E2 (PGE2) and lipoxin A4 (LXA4) and other similar BALs. This implies that MSCs that have limited or low capacity to secrete BALs may be unable to bring about their beneficial actions. This proposal implies that pretreatment of MSCs with BALs enhance their physiological action or improve their (MSCs) anti-inflammatory and disease resolution capacity to a significant degree. Thus, the beneficial action of MSCs reported in the management of COVID-19 could be attributed to their ability to secrete BALs, especially PGE2 and LXA4. Since PGE2, LXA4 and their precursors AA (arachidonic acid), dihomo-gamma-linolenic acid (DGLA) and gamma-linolenic acid (GLA) inhibit the production of pro-inflammatory IL-6 and TNF-α, they could be employed to treat cytokine storm seen in COVID-19, immune check point inhibitory (ICI) therapy, sepsis and ARDS (acute respiratory disease). This is further supported by the observation that GLA, DGLA and AA inactivate enveloped viruses including COVID-19. Thus, infusions of appropriate amounts of GLA, DGLA, AA, PGE2 and LXA4 are of significant therapeutic benefit in COVID-19, ICI therapy and other inflammatory conditions including but not limited to sepsis. AA is the precursor of both PGE2 and LXA4 suggesting that AA is most suited for such preventive and therapeutic approach.

Curcumin protects bone biomechanical properties and microarchitecture in type 2 diabetic rats with osteoporosis via the TGFβ/Smad2/3 pathway

Type 2 diabetic osteoporosis (T2DOP) has become a common secondary cause of osteoporosis that accelerates bone loss and leads to bone fractures. The aim of the current study was to investigate the association between the anti-osteoporotic effect of curcumin (Cur) and the transforming growth factor (TGF)β/Smads signaling pathway. Male Sprague-Dawley rats were used in the experiments. The type 2 diabetes mellitus (T2DM) animals were treated with Cur for 8 weeks and blood lipid markers, bone microstructure and bone biomechanics were then evaluated. The mRNA expression levels of TGFβ1, type I TGFβ receptor (TβRI), TβRII and Smad2/3 were determined using reverse transcription-quantitative PCR (RT-qPCR) and immunohistochemistry. The body weight of rats with type 2 diabetes-induced osteoporosis increased (P<0.05), while the lipid (total cholesterol, triglyceride and low-density lipoprotein) and fasting blood glucose levels were decreased by Cur (P<0.05). In addition, Cur significantly improved bone biomechanical properties (maximum load, breaking load, elastic load and the bone rigidity coefficient) and preserved bone microarchitecture (P<0.05). The RT-qPCR and IHC results revealed that Cur increased TGFβ1, TβRI, TβRII and Smad2/3 expression levels and promoted Smad2/3 phosphorylation in bones. The present results also indicated that Cur regulated lipid and glucose levels, improved bone biomechanical properties and preserved bone microarchitecture, and that these effects may be mediated via TGFβ/Smad2/3 pathway activation.

Resolvin D1 Ameliorates Nicotinamide-streptozotocin-induced Type 2 Diabetes Mellitus by its Anti-inflammatory Action and Modulating PI3K/Akt/mTOR Pathway in the Brain

OBJECTIVE

To study whether resolvin D1 (RvD1), a metabolite of docosahexaenoic acid (DHA), prevents NA-STZ-induced type 2 diabetes mellitus (type 2 DM) in vivo and if so, what could be the mechanism of this action.

MATERIAL AND METHODS

Single intra-peritoneal (i.p) injection of NA-STZ (175 mg/kg body weight of NA and 65 mg/kg of STZ) was injected simultaneously with RvD1 (60 ng/animal) (injected for 5 consecutive days) to Wistar rats. The effect of RvD1 on plasma glucose levels and apoptotic (Bcl2/Bax) and inflammatory (NF-κB/iNOS) protein expression, plasma lipoxin A4 and BDNF (brain-derived neurotrophic factor) were studied. Protein expressions of PI3k-Akt-mTOR pathway along with histopathological studies of brain were also evaluated.

RESULTS

NA-STZ-induced type 2 DM rats showed hyperglycemia, enhanced plasma IL-6/TNF-α (p ≤0.01), reduced plasma BDNF (p ≤0.01) and LXA4 (p ≤0.01) levels and low BDNF in pancreatic, hepatic and brain tissues (p <0.001), which were restored to near normal (p ≤0.01) in RvD1 treated group. RvD1 increased insulin sensitivity by suppressing inflammation (NF-κB/iNOS) (p ≤0.01) and decreasing apoptosis (Bcl2/Bax) and restoring BDNF and LXA4 levels to near normal. RvD1 treatment increased phosphorylation of Akt (Ser473), and subsequent activation (phosphorylation) of downstream signaling molecules of PI3K and mTOR indicating that RvD1 acts through PI3K/Akt/mTOR axis.

DISCUSSION

RvD1 is effective in preventing NA-STZ-induced type 2 DM in vivo by suppressing oxidative damage, enhancing the production of anti-inflammatory LXA4 and enhancing neuronal cell survival by augmenting the production of BDNF. Thus, RvD1 may be of benefit not only in preventing diabetes mellitus but also diabetes associated Alzheimer's disease and memory loss.

Anti-hyperglycemic activity of myricetin, through inhibition of DPP-4 and enhanced GLP-1 levels, is attenuated by co-ingestion with lectin-rich protein

Dipeptidyl peptidase-4 (DPP-4) is a proteolytic enzyme responsible for the rapid degradation of Glucagon-like peptide 1 (GLP-1) that is required for the secretion of insulin. DPP-4 also influences activation of node like receptor family, pyrin domain containing 3 (NLRP3) inflammasome under diabetic conditions. Although several polyphenols are reported for various bioactivities, they are consumed as part of the food matrix and not in isolation. Horsegram (Macrotyloma uniflorum) is a rich source of myricetin (Myr) (35 μg/g flour), reported for its anti-hyperglycemic effect. In this investigation, we aimed to study the effect of Myr, singly, and in the presence of co-nutrient horsegram protein (HP) on DPP-4 activity and its consequential impact on GLP-1, insulin, and NLRP3 inflammasome in high-fat diet and single low dose streptozotocin (STZ)-induced diabetic male Wistar rats. In diabetic control (DC), the activity of DPP-4 and its expression were higher compared to treated groups. The consequential decrease in the circulating GLP-1 levels in the DC group, but not treated groups, further indicated the effectiveness of our test molecules under diabetic conditions. Specifically, Myr decreased DPP-4 activity and its expression levels with enhanced circulating GLP-1 and insulin levels. Myr administration also resulted in a lessening of diabetes-induced NLRP3 inflammasome activation and enhanced antioxidant enzyme activities. HP also proved to be efficient in reducing elevated blood glucose levels and enhancing antioxidant enzyme activities. However, Myr, in the presence of HP as a co-nutrient, had diminished capacity to inhibit DPP-4 and, consequently, reduced potential in ameliorating diabetic conditions. Myr proved to be a potent inhibitor of DPP-4 in vitro and in vivo, resulting in enhanced circulating GLP-1 and insulin levels, thereby improving diabetic conditions. Though Myr and HP, individually ameliorate diabetic conditions, their dietary combination had reduced efficiency.

Molecular pathobiology of scleritis and its therapeutic implications

Scleritis and other autoimmune diseases are characterized by an imbalance in the levels of pro-inflammatory and anti-inflammatory molecules with the balance tilted more towards the former due to the failure of recognition of self. The triggering of inflammatory process could be ascribed to the presence of cytoplasmic DNA/chromatin that leads to activation of cytosolic DNA-sensing cGAS-STING (cyclic GMP-AMP synthase linked to stimulator of interferon genes) pathway and enhanced expression of NF-κB that results in an increase in the production of pro-inflammatory bioactive lipids. Bioactive lipids gamma-linolenic acid (GLA), dihomo-GLA (DGLA), prostaglandin E1 (PGE1), prostacyclin (PGI2) and lipoxin A4, resolvins, protectins and maresins have anti-inflammatory actions, bind to DNA to render it non-antigenic and are decreased in autoimmune diseases. These results suggest that efforts designed to enhance the production of anti-inflammatory bioactive lipids may form a new approach to autoimmune diseases. Local injection or infusion of lipoxins, resolvins, protectins and maresins or their precursors such as arachidonic acid may be exploited in the prevention and management of autoimmune diseases including scleritis, uveitis and lupus/rheumatoid arthritis.

PM2.5 aggravates diabetes via the systemically activated IL-6-mediated STAT3/SOCS3 pathway in rats' liver

PM_2.5 exposure aggravates type 2 diabetes, in which inflammatory factors play an important role. In this study, we aimed to explore the mechanisms responsible for aggravating diabetes after PM_2.5 exposure, and study the roles of inflammatory factors in insulin-resistant type 2 diabetes. Our study indicated that short-time PM_2.5 exposure enhances insulin resistance in type 2 diabetic rats and significantly raises inflammatory factors, including IL-6, TNF-α, and MCP-1, in lungs. However, we found that of these inflammatory factors only IL-6 levels are elevated in blood, liver, adipose tissue, and macrophages, but not in skeletal muscle. IL-6 induced activation of the STAT3/SOCS3 pathway in liver, but not other downstream pathways including STAT1, ERK1/2, and PI3K. Both STAT3 inhibition and IL-6 neutralization effectively alleviated the disorders of glucose metabolism after PM_2.5 exposure. Taken together, this suggests that the systemic increase in IL-6 may play an important role in the deterioration of the type 2 diabetes via IL-6/STAT3/SOCS3 pathway in liver after short-time exposure to PM_2.5. Besides, we unexpectedly found a stronger resistance to the PM_2.5 exposure-induced increase in IL-6 in skeleton muscle than those of many other tissues.

PUFAs, BDNF and lipoxin A4 inhibit chemical-induced cytotoxicity of RIN5F cells in vitro and streptozotocin-induced type 2 diabetes mellitus in vivo

Objective

To study whether minimal doses of arachidonic acid (AA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) and lipoxin A4 (LXA4) and brain-derived neurotrophic factor (BDNF), when used in combination can protect RIN5F cells from chemical-induced cytotoxicity. As a corollary, to know whether plasma BDNF and LXA4 are altered in STZ-induced type 2 DM animals.

Materials and methods

RIN5F cells, alloxan (AL), streptozotocin (STZ), doxorubicin (DB), and benzo(a)pyrene (BP) were used in this study. Chemical-induced apoptosis and changes in antioxidants, lipid peroxides and nitric oxide (NO) and LXA4 and BDNF levels in RIN5F cells were studied. Alterations in plasma concentrations of BDNF and LXA4 in STZ-induced type 2 diabetes animals was estimated.

Results

BDNF, LXA4 and AA, EPA and DHA protected (P < 0.001 and P < 0.01 respectively) against AL/STZ/DB/BP-induced toxicity to RIN5F cells in vitro. AL/ STZ/DB/BP inhibited BDNF and LXA4 production by RIN5F cells and were restored to normal by AA, EPA and DHA. Sub-optimal doses of BDNF, LXA4, AA and EPA when used in combination protected against cytotoxic action of AL/STZ/DB/BP on RIN5F cells in vitro by restoring LXA4/BDNF levels and altered antioxidant/lipid peroxides/NO levels (P < 0.01) to normal. STZ (65 mg/kg)-induced type 2 diabetes mellitus animals showed reduced plasma BDNF and LXA4 levels (P < 0.001).

Discussion

AL/STZ/DB/BP-induced cytotoxicity to RIN5F cells in vitro can be prevented by BDNF, LXA4 and AA. AL/STZ/DB/BP are cytotoxic, possibly, by suppressing the production of LXA4 and BDNF in RIN5F cells. STZ-induced type 2 DM animals have decreased plasma levels of LXA4 and BDNF.

Conclusion

The results of the present study suggest that BDNF, LXA4, EPA, DHA, AA, GLA and BDNF protect pancreatic β cells from the cytotoxic action of various chemicals and prevent development of diabetes mellitus. LXA4 seems to be the mediator of these cytoprotective actions of BDNF and PUFAs suggesting a close interaction exists among these molecules (BDNF, PUFAs and LXA4). Hence, methods developed to deliver a combination of PUFAs (especially AA), LXA4 and BDNF may prevent development of diabetes mellitus (both type 1 and type 2).

Macrophage polarization is linked to Ca2+-independent phospholipase A2β-derived lipids and cross-cell signaling in mice

Phospholipases A₂ (PLA₂s) catalyze hydrolysis of the sn-2 substituent from glycerophospholipids to yield a free fatty acid (i.e., arachidonic acid), which can be metabolized to pro- or anti-inflammatory eicosanoids. Macrophages modulate inflammatory responses and are affected by Ca²⁺-independent phospholipase A₂ (PLA₂)β (iPLA₂β). Here, we assessed the link between iPLA₂β-derived lipids (iDLs) and macrophage polarization. Macrophages from WT and KO (iPLA₂β-/-) mice were classically M1 pro-inflammatory phenotype activated or alternatively M2 anti-inflammatory phenotype activated, and eicosanoid production was determined by ultra-performance LC ESI-MS/MS. As a genotypic control, we performed similar analyses on macrophages from RIP.iPLA₂β.Tg mice with selective iPLA₂β overexpression in β-cells. Compared with WT, generation of select pro-inflammatory prostaglandins (PGs) was lower in iPLA₂β^-/- , and that of a specialized pro-resolving lipid mediator (SPM), resolvin D2, was higher; both changes are consistent with the M2 phenotype. Conversely, macrophages from RIP.iPLA₂β.Tg mice exhibited an opposite landscape, one associated with the M1 phenotype: namely, increased production of pro-inflammatory eicosanoids (6-keto PGF₁α, PGE₂, leukotriene B₄) and decreased ability to generate resolvin D2. These changes were not linked with secretory PLA₂ or cytosolic PLA₂α or with leakage of the transgene. Thus, we report previously unidentified links between select iPLA₂β-derived eicosanoids, an SPM, and macrophage polarization. Importantly, our findings reveal for the first time that β-cell iPLA₂β-derived signaling can predispose macrophage responses. These findings suggest that iDLs play critical roles in macrophage polarization, and we posit that they could be targeted therapeutically to counter inflammation-based disorders.

Specialized pro-resolving mediators in diabetes: novel therapeutic strategies

Diabetes mellitus (DM) is an important metabolic disorder characterized by persistent hyperglycemia resulting from inadequate production and secretion of insulin, impaired insulin action, or a combination of both. Genetic disorders and insulin receptor disorders, environmental factors, lifestyle choices and toxins are key factors that contribute to DM. While it is often referred to as a metabolic disorder, modern lifestyle choices and nutrient excess induce a state of systemic chronic inflammation that results in the increased production and secretion of inflammatory cytokines that contribute to DM. It is chronic hyperglycemia and the low-grade chronic-inflammation that underlies the development of microvascular and macrovascular complications leading to damage in a number of tissues and organs, including eyes, vasculature, heart, nerves, and kidneys. Improvements in the management of risk factors have been beneficial, including focus on intensified glycemic control, but most current approaches only slow disease progression. Even with recent studies employing SGLT2 inhibitors demonstrating protection against cardiovascular and kidney diseases, kidney function continues to decline in people with established diabetic kidney disease (DKD). Despite the many advances and a greatly improved understanding of the pathobiology of diabetes and its complications, there remains a major unmet need for more effective therapeutics to prevent and reverse the chronic complications of diabetes. More recently, there has been growing interest in the use of specialised pro-resolving mediators (SPMs) as an exciting therapeutic strategy to target diabetes and the chronic complications of diabetes.

Bioactive lipids as modulators of immune check point inhibitors

It is proposed that arachidonic acid (AA, 20:4 n-6) and other polyunsaturated fatty acids (PUFAs) in combination with immune check point inhibitors and tumor infiltrating lymphocytes (TILs) enhances the activity of T and NK cells and macrophages and thus, aids in the elimination of tumor cells and suppresses inflammatory side effects due to immune check point inhibitors.

Arachidonic acid-rich ARASCO oil has anti-inflammatory and antidiabetic actions against streptozotocin + high fat diet induced diabetes mellitus in Wistar rats

OBJECTIVES

The aim of this study was to investigate the effects of arachidonic acid (AA)-rich ARASCO oil on high-fat diet (HFD) + streptozotocin (STZ)-induced diabetes mellitus in male Wistar rats and its possible mechanisms of action.

METHODS

Male Wistar rats with HFD + STZ-induced diabetes were employed in the present study. ARASCO oil was administered orally for the first 7 d consecutively, followed by once weekly throughout the study (14 wk). At various time points, blood glucose and body weight and oral glucose tolerance tests were measured. At the end of the study, animals were sacrificed to collect plasma and various organs and stored at -80°C. Plasma insulin, tumor necrosis factor-α, interleukin-6, and lipoxin A4 were measured. Expression of the following genes was determined: nuclear factor-κΒ (NF-κB), cyclooxygenase-2 (COX-2), 12-lipoxygenase (12-LOX) in pancreas and lipocalin 2 (LPCLN2) in adipose tissue. Various antioxidants were measured in the plasma and other tissues. Area under the curve and insulin sensitivity index were assessed by computing homeostatic model of assessment for insulin resistance, quantitative insulin check index, Matsuda, and Belfiore indices.

RESULTS

ARASCO oil treatment decreased hyperglycemia, restored insulin sensitivity, suppressed inflammation, enhanced plasma lipoxin A4 levels, and reversed altered antioxidant status to near normal in animals with HFD + STZ-induced diabetes.

CONCLUSION

These results suggest that ARASCO, a rich source of AA, can prevent HFD + STZ-induced diabetes in Wistar rats owing to its anti-inflammatory action. It remains to be seen whether ARASCO oil is useful in preventing or postponing the development of type 2 diabetes mellitus in humans.

Vitamin C for Type 2 Diabetes Mellitus and Hypertension

It is suggested that supplementation of vitamin C reduces hyperglycemia and lowers blood pressure in hypertensives by enhacing the formation of prostaglandin E1 (PGE1), PGI2 (prostacyclin), endothelial nitric oxide (eNO), and restore essential fatty acid (EFA) metabolism to normal and enhance the formation of lipoxin A4 (LXA4), a potent anti-inflammatory, vasodilator and antioxidant. These actions are in addition to the ability of vitamin C to function as an antioxidant. In vitro and in vivo studies revealed that PGE1, PGI2 and NO have cytoprotective and genoprotective actions and thus, protect pancreatic β and vascular endotheilial cells from the cytotoxic actions of endogenous and exogenous toxins. AA, the precursor of LXA4 and LXA4 have potent anti-diabetic actions and their plasma tissue concentrations are decreased in those with diabetes mellitus and hypertension. Thus, vitamin C by augmenting the formation of PGE1, PGI2, eNO, LXA4 and restoring AA content to normal may function as a cytoprotective, anti-mutagenic, vasodilator and platelet anti-agregator actions that explains its benefical action in type 2 diabetes mellitus and hypertension.

Beneficial role of bioactive lipids in the pathobiology, prevention, and management of HBV, HCV and alcoholic hepatitis, NAFLD, and liver cirrhosis: A review

It has been suggested that hepatitis B virus (HBV)- and hepatitis C virus (HCV)-induced hepatic damage and cirrhosis and associated hypoalbuminemia, non-alcoholic fatty liver disease (NAFLD), and alcoholic fatty liver disease (AFLD) are due to an imbalance between pro-inflammatory and anti-inflammatory bioactive lipids. Increased tumour necrosis factor (TNF)-α production induced by HBV and HCV leads to a polyunsaturated fatty acid (PUFA) deficiency and hypoalbuminemia. Albumin mobilizes PUFAs from the liver and other tissues and thus may aid in enhancing the formation of anti-inflammatory lipoxins, resolvins, protectins, maresins and prostaglandin E1 (PGE1) and suppressing the production of pro-inflammatory PGE2. As PUFAs exert anti-viral and anti-bacterial effects, the presence of adequate levels of PUFAs could inactivate HCV and HBV and prevent spontaneous bacterial peritonitis observed in cirrhosis. PUFAs, PGE1, lipoxins, resolvins, protectins, and maresins suppress TNF-α and other pro-inflammatory cytokines, exert cytoprotective effects, and modulate stem cell proliferation and differentiation to promote recovery following hepatitis, NAFLD and AFLD. Based on this evidence, it is proposed that the administration of albumin in conjunction with PUFAs and their anti-inflammatory products could be beneficial for the prevention of and recovery from NAFLD, hepatitis and cirrhosis of the liver. NAFLD is common in obesity, type 2 diabetes mellitus, and metabolic syndrome, suggesting that even these diseases could be due to alterations in the metabolism of PUFAs and other bioactive lipids. Hence, PUFAs and co-factors needed for their metabolism and albumin may be of benefit in the prevention and management of HBV, HCV, alcoholic hepatitis and NAFLD, and liver cirrhosis.

Effect of Cyclocarya Paliurus on Hypoglycemic Effect in Type 2 Diabetic Mice

Background

The aim of this study was to assess the hypoglycemic effect of Cyclocarya paliurus extract (CPE) on diabetes mellitus (DM) mice.

Material/Methods

A DM mouse model was established to test FBG, TC, and TG. The DM mice were divided into 3 groups: a DM group, a DM+CPE (0.5 g/Kg) group, and a DM+CPE (1.0 g/Kg) group. The FBG and body weight were measured. The glucose tolerance ability was determined by OGTT test. FINS was measured to calculate ISI and IRI. Serum MDA, SOD, and GSH-Px levels were detected. NIT-1 cells were cultured in vitro and divided into 4 groups: a control group, a STZ group, a STZ+CPE (80 μg/mL) group, and a STZ+CPE (160 μg/mL) group. Cell apoptosis and ROS content were assessed by flow cytometry. Cell proliferation was detected by EdU staining.

Results

Compared with the control group, FBG, TC, and TG were significantly increased in the DM group. CPE gavage obviously reduced FBG level, increased body weight, enhanced glucose tolerance, elevated FINS level and ISI, and reduced IRI, all in a dose-dependent manner. CPE gavage reduced serum MDA content and increased SOD and GSH-Px enzyme activities in DM mice. STZ markedly enhanced ROS production, induced apoptosis, and inhibited proliferation in NIT-1 cells. CPE treatment clearly reduced ROS production and apoptosis, enhanced cell proliferation, and alleviated STZ damage to NIT-1 cells.

Conclusions

CPE has the effects of decreasing blood glucose and insulin resistance, and enhancing glucose tolerance in DM mice, which may be related to its effects of reducing oxidation and reduced apoptosis, and relieving STZ in pancreatic beta cell injury.

Arachidonic Acid Metabolites in Cardiovascular and Metabolic Diseases

Lipid and immune pathways are crucial in the pathophysiology of metabolic and cardiovascular disease. Arachidonic acid (AA) and its derivatives link nutrient metabolism to immunity and inflammation, thus holding a key role in the emergence and progression of frequent diseases such as obesity, diabetes, non-alcoholic fatty liver disease, and cardiovascular disease. We herein present a synopsis of AA metabolism in human health, tissue homeostasis, and immunity, and explore the role of the AA metabolome in diverse pathophysiological conditions and diseases.