Normoglycemic Mice Research Articles

A modified fluorescent sensor for reporting glucose concentration in the airway lumen.

We have modified the periplasmic Escherichia coli glucose/galactose binding protein (GBP) and labelled with environmentally sensitive fluorophores to further explore its potential as a sensor for the evaluation of glucose concentration in airway surface liquid (ASL). We identified E149C/A213R GBP labelled with N,N’-Dimethyl-N-(iodoacetyl)-N’-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)ethylenediamine (IANBD, emission wavelength maximum 536nm) with a Kd for D-glucose of 1.02mM and a fluorescence dynamic range of 5.8. This sensor was specific for D-glucose and exhibited fluorescence stability in experiments for several hours. The use of E149C/A213R GBP-IANBD in the ASL of airway cells grown at air-liquid-interface (ALI) detected an increase in glucose concentration 10 minutes after raising basolateral glucose from 5 to 15mM. This sensor also reported a greater change in ASL glucose concentration in response to increased basolateral glucose in H441 airway cells compared to human bronchial epithelial cells (HBEC) and there was less variability with HBEC data than that of H441 indicating that HBEC more effectively regulate glucose movement into the ASL. The sensor detected glucose in bronchoalveolar lavage fluid (BALf) from diabetic db/db mice but not normoglycaemic wildtype mice, indicating limited sensitivity of the sensor at glucose concentrations <50μM. Using nasal inhalation of the sensor and spectral unmixing to generate images, E149C/A213R GBP-IANBD fluorescence was detected in luminal regions of cryosections of the murine distal lung that was greater in db/db than wildtype mice. In conclusion, this sensor provides a useful tool for further development to measure luminal glucose concentration in models of lung/airway to explore how this may change in disease.

In-Vitro α-amylase, α-glucosidase Inhibitory Activities and In-Vivo Anti-Hyperglycemic Potential of Different Dosage Forms of Guduchi (Tinospora Cordifolia [Willd.] Miers) Prepared With Ayurvedic Bhavana Process.

Guduchi (Tinospora cordifolia [Willd.] Miers) is a flagship rejuvenating herb of Ayurveda with reported anti-diabetic potential. In the present study, different dosage forms of Guduchi stem (growing on neem tree) were developed by adopting Ayurvedic pharmaceutical process of Bhavana (levigation). Guduchi Churna (GC) was subjected to 07 times Bhavana separately with its own extracted juice, decoction and potable water, and dosage forms namely Svarasa Bhavita Guduchi Churna (SBGC), Kwatha Bhavita Guduchi Churna (KBGC), and Jala Bhavita Guduchi Churna (JBGC) were prepared. The present study was aimed to evaluate the role of Bhavana on the potentiation of therapeutic properties of Guduchi. Sequential solvent extracts (5, 10, 15 and 25%) of GC, SBGC, KBGC and JBGC were prepared in different solvents [phosphate buffer, hexane, dichloromethane (DCM), chloroform] and screened for the α-amylase and α-glucosidase inhibitory activity. The results revealed that phosphate buffer and DCM extracts of SBGC exhibited strong α-amylase inhibitory potential (>80% inhibition at 25% concentration) followed by KBGC, JBGC and GC with reference to the standard acarbose. In α-glucosidase inhibitory activity, maximum inhibition was observed in DCM and chloroform extracts of SBGC (>85% inhibition at 25% concentration), followed by KBGC (>80% inhibition at 25% concentration), JBGC and GC. In vivo anti-hyperglycemic studies were carried out by oral glucose tolerance test in Swiss albino mice. Test drugs (JBGC, KBGC, SBGC) treated groups showed marginal decrease of blood glucose levels in normo glycemic mice. However, the blood glucose level in test drug JBGC, KBGC and SBGC treated groups was still within normal range in overnight fasted mice. In oral glucose tolerance test, among all dosage forms SBGC (51.08%) produced pronounced anti-hyperglycemic effect followed by KBGC (42.57%) at a dose of 520 mg/kg. The GC, JBGC, KBGC and SBGC samples were also standardized using berberine (a well established anti-diabetic compound) as a marker compound by HPTLC fingerprint analysis. Findings of the present study indicate that SBGC and KBGC can be used in the treatment of diabetes mellitus and gives supporting evidence to Ayurvedic claims that the Bhavana process has pharmaceutico-therapeutic significance in Ayurvedic drug development.

Hyperglycemia results in decreased immune cell infiltration and increased viral load in the lung in a mouse model of RSV infection

Respiratory Syncytial virus (RSV) infection is a feared disease in vulnerable populations with impaired immune responses. There is currently no vaccine against RSV and young children along with elderly people are at increased risk of severe or sometimes life-threatening RSV infection. Hyperglycemia with immunomodulatory patterns can impact on infectious disease outcomes and immune system responses in diabetic patients. Even though research continues to uncover the complex mechanisms underlying RSV immunopathogenesis and diabetes mellitus disease separately, limited information is available about interaction between these two phenomena. Here, we evaluated the influence of hyperglycemia as the hallmark of diabetes mellitus disease on the pathogenesis and immunopathogenesis of RSV in a mouse model. In this experiment, hyperglycemia was induced by intraperitoneal injection of Streptozotocin (STZ), and after diabetes confirmation, mice were infected with RSV-A2, and the immune responses were followed for 5 days until the mice were sacrificed. Analyses on airway immune cell influx, T-Lymphocyte subtypes, cytokines secretion, lung histopathology, and viral load were conducted. Our results showed that hyperglycemia resulted in reduced lung immune cells infiltration totally and it was associated with decreased pathological damage of the lung. Following RSV infection in hyperglycemic mice, the ratio of CD4/CD8 T-Lymphocytes due to CD8+ depletion, increased. Furthermore, the level of IFN-γ and IL-17A cytokines decreased, whereas IL-10 showed an upward trend and the viral load increased in hyperglycemic mice compared with normoglycemic mice. In conclusion, these findings indicate that hyperglycemia can ameliorate and downregulate RSV-induced inflammatory and antiviral responses, and result in increment of viral load.

Antihyperglycemic and Antilipidemic Properties of a Tea Infusion of the Leaves from Annona cherimola Miller on Streptozocin-Induced Type 2 Diabetic Mice.

The antihyperglycemic and antilipidemic effects of the tea infusion extracts of leaves from Annona cherimola Miller (IELAc-0.5, IELAc-1.5, and IELAc-3.0) were evaluated on normoglycemic (NG) and streptozocin-induced diabetic (STID) mice. In the acute test, IELAc-1.5 at 300 mg/kg bodyweight (bw) exhibited antihyperglycemic activity on STID mice since the first hour of treatment. Then, its antidiabetic potential was analyzed in a subchronic evaluation. IELAc-1.5 was able to reduce the blood glucose level, glycated hemoglobin (HbA1c), cholesterol (CHO), and triglycerides (TG); high-density lipoprotein (HDL) showed an increase at the end of treatment. IELAc-1.5 did not modify the urine profile at the end of the evaluation, and neither toxicity nor macroscopic organ damage were observed in acute and subchronic assays. In addition, a major flavonol glycoside present in the tea infusion extracts was identified using high-performance liquid chromatography with diode array detection (HPLC-DAD). The analysis of the tea infusion extracts by HPLC revealed that rutin was the major component. This study supports the use of tea infusions from Annona cherimola for the treatment of diabetes and suggests that rutin could be responsible, at least in part, for their antidiabetic properties.

The lack of Irs2 induces changes in the immunocytochemical expression of aromatase in the mouse retina

Insulin receptor substrate (Irs) belongs to a family of proteins that mediate the intracellular signaling of insulin and IGF-1. Insulin receptor substrate 2 (Irs2) is necessary for retinal function, since its failure in Irs2-deficient mice in hyperglycemic situation promotes photoreceptor degeneration and visual dysfunction, like in diabetic retinopathy. The expression of P450 aromatase, which catalyzes androgen aromatization to form 17ß-estradiol, increases in some neurodegenerative diseases thus promoting the local synthesis of neuroestrogens that exert relevant neuroprotective functions. Aromatase is also expressed in neurons and glial cells of the central nervous system (CNS), including the retina. To further understand the role of Irs2 at the retinal level, we performed an immunocytochemical study in adult normoglycemic Irs2-deficient mice. For this aim, the retinal immunoexpression of neuromodulators, such as aromatase, glutamine synthetase (GS), and tyrosine hydroxylase (TH) was analyzed, joint to a morphometric and planimetric study of the retinal layers. Comparing with wild-type (WT) control mice, the Irs2-knockout (Irs2-KO) animals showed a significant increase in the immunopositivity to aromatase in almost all of the retinal layers. Besides, Irs2-KO mice exhibited a decreased immunopositive reaction for GS and TH, in Müller and amacrine cells, respectively; morphological variations were also found in these retinal cell types. Furthermore, the retina of Irs2-KO mice displayed alterations in the structural organization, and a generalized decrease in the retinal thickness was observed in each of the layers, except for the inner nuclear layer. Our findings suggest that the absence of Irs2 induces retinal neurodegenerative changes in Müller and amacrine cells that are unrelated to hyperglycemia. Accordingly, in the Irs2-KO mice, the increased retinal immunocytochemical reactivity of aromatase could be associated with an attempt to repair such neural retina injuries by promoting local neuroprotective mediators.

Curcuma longa supplement increases anxiety-like behavior and blood glucose level in Swiss albino mice

Curcuma longa (C. longa), also known as curcumin, is a lipophilic polyphenol substance proven to have cholesterol-lowering, anti-diabetic, anti-inflammatory, anti-oxidant, and anti-cancer properties in both in vitro and in vivo models. Most previous studies investigated the effect of C. longa on diabetic mice and therefore, there is a need to investigate the effect of C. longa on normoglycemic mice. Depression is a common consequence of anxiety that affects 21% of the world’s population. Since the prevalence of diabetes and depression is on the rise globally, it is important to search for safer and cost-effective management for these disorders. In doing so, it is therefore essential to investigate its effect in normoglycemic mice. The current study determines the effect of C. longa on blood glucose level and anxiety-like behavior in normoglycemic Swiss albino mice. A total of 20 mice were divided into four groups of five (n=5 per group). Group I (control) received distilled water 10 ml/kg, groups II, III, and IV received C. longa at 5%, 10%, and 20%, respectively, for 14 days. We found that 20% C. longa group showed a significant (p&lt;0.05) increase in fasting blood glucose level (195.84±14.46 mg/dl) after 14 days of administration compared with the control group (134.60±4.52 mg/dl). We also found that 20% C. longa increased the anxiety-like behavior in normoglycemic Swiss albino mice compared with the control group. However, there was no significant (p&gt;0.05) difference in both fasting blood glucose level and anxiety-like behavior between the mice treated with 5% and 10% C. longa and the control group. This study indicates that C. longa at high concentration is unsafe for consumption by normoglycemic Swiss albino mice.

Improved diabetic wound healing by LFcinB is associated with relevant changes in the skin immune response and microbiota

Bovine lactoferricin (LFcinB) has antimicrobial and immunomodulatory properties; however, the effects on diabetic wound healing remain poorly understood. The wound healing potential of LFcinB was investigated with in vitro, ex vivo, and in vivo models. Cell migration and proliferation were tested on keratinocytes and on porcine ears. A type 1 diabetic mouse model was also used to evaluate wound healing kinetics, bacterial diversity patterns, and the effect of LFcinB on oxidative stress, macrophage phenotype, angiogenesis, and collagen deposition. LFcinB increased keratinocyte migration in vitro (p < 0.05) and ex vivo (p < 0.001) and improved wound healing in diabetic mice (p < 0.05), though not in normoglycemic control mice. In diabetic mouse wounds, LFcinB treatment led to the eradication of Bacillus pumilus, a decrease in Staphylococcus aureus, and an increase in the Staphylococcus xylosus prevalence. LFcinB increased angiogenesis in diabetic mice (p < 0.01), but this was decreased in control mice (p < 0.05). LFcinB improved collagen deposition in both diabetic and control mice (p < 0.05). Both oxidative stress and the M1-to-M2 macrophage ratios were decreased in LFcinB-treated wounds of diabetic animals (p < 0.001 and p < 0.05, respectively) compared with saline, suggesting a downregulation of inflammation in diabetic wounds. In conclusion, LFcinB treatment demonstrated noticeable positive effects on diabetic wound healing.

Peritoneal dissolved oxygen and function of encapsulated adult porcine islets transplanted in streptozotocin diabetic mice.

Alginate-encapsulated islet xenografts have restored normoglycemia in diabetic animals for various periods of time. Plausible mechanisms of graft failure in vivo include immune rejection and hypoxia. We sought to understand the effects of encapsulated adult porcine islet (API) dosage on the peritoneal dissolved oxygen (DO) level in correlation to the achieved glycemic regulation in diabetic mice. Adult porcine islets encapsulated in barium alginate were transplanted intraperitoneally in streptozotocin diabetic BALB/c mice at 6000 and 4000 islet equivalents (IEQ) and in normal mice at 500 IEQ; APIs encapsulated in calcium alginate were transplanted at 6000 IEQ in diabetic mice. In all cases, cell-free barium alginate capsules containing a perfluorocarbon emulsion were co-implanted for DO measurements using 19 F NMR spectroscopy. Blood glucose levels and peritoneal DO were measured over 60days or until graft failure. Explanted capsules were evaluated microscopically and histologically. Both barium and calcium alginate-encapsulated APIs at 6000 IEQ reversed diabetes until day 60; barium alginate-encapsulated APIs at 4000 IEQ also reversed diabetes but with a higher failure rate. Transplanted APIs significantly reduced the peritoneal DO, approximately in a dose-dependent manner. The number of viable islets and the insulin content per capsule decreased over time. Capsules retrieved from normoglycemic mice exhibited minimal host cell adherence. Transplantation of encapsulated APIs can reduce peritoneal DO to severely hypoxic levels. Although normoglycemia could be maintained within the study period, the DO levels suggest that hypoxia is a factor contributing to loss of islet viability and insulin secretion with time in mice.

Blackthorn Flower Extract Impact on Glycaemic Homeostasis in Normoglycaemic and Alloxan-Induced Hyperglycaemic C57BL/6 Mice.

SUMMARYResearch backgroundThe use of plants and their extracts in treatments of chronic diseases is widely known in traditional medicine. The aim of this study is to determine the effects of 10-day consumption of blackthorn (Prunus spinosa L.) flower extract on blood glucose, glycaemic load, serum α-amlyase activity and insulin concentration in normoglycaemic and hyperglycaemic (alloxan-induced) mice model.Experimental approachNormoglycaemic and hyperglycaemic (treated with alloxan, 150 mg per kg body mass) C57BL/6 mice were administered daily, during 10 days, blackthorn flower extract by gavage. The sugar mass concentration within the extract was determined by HPLC analysis. In mice, blood and serum blood glucose concentrations, and oral glucose tolerance test were determined by blood glucometer. Serum insulin concentration was determined by ELISA assay and α-amylase activity by colourimetric assay.Results and conclusionsThe blackthorn flower extract increased glucose concentrations in normoglycaemic mice by 30% after the 1st and 5th day and by 17% after the 10th day of consumption. It is a consequence of released sugars because sugar analysis revealed 59.8 mg/L monosaccharides, mainly fructose (55.7 mg/L) and glucose (24.3 mg/L) in the extract. On the contrary, the extract consumption reduced serum blood glucose in hyperglycaemic mice by 29% after 10 days of treatment. Oral glucose tolerance test also confirmed that in the hyperglycaemic group treated with blackthorn flower extract glucose homeostasis was improved and showed decrease in blood glucose. Serum insulin concentration increased by 49% and serum α-amylase activity by 46% after 10 days of treatment with blackthorn flower extract in hyperglycaemic group. Thus, it can be concluded that blackthorn flower extract improved glucose tolerance, enhanced insulin secretion and lowered serum α-amylase activity.Novelty and scientific contributionThe obtained results show for the first time the potential of blackthorn (Prunus spinosa L.) flower extract in hyperglycaemia management.

Redox treatment ameliorates diabetes mellitus-induced skin flap necrosis via inhibiting apoptosis and promoting neoangiogenesis.

Intractable wound healing is the habitual problem of diabetes mellitus. High blood glucose limits wound healing by interrupting inflammatory responses and inhibiting neoangiogenesis. Oxidative stress is commonly thought to be a major pathogenic cause of diabetic complications. Edaravone (3-methyl-1-phenyl-2-pyrazolin-5-one, EDV) is a free radical scavenger which suppress oxidative stress. This study investigates whether EDV can reduce oxidative stress in wound healing HaCaT/human dermal fibroblasts cells (HDFs) in vitro and in vivo animal model. Cell viability and wound healing assays, FACS flow cytometry, and Hoechst 33342 staining were performed to confirm apoptosis and cytotoxicity in H2O2 and EDV-treated HaCaT and HDFs. A streptozotocin-induced hyperglycemic animal model was made in adult C57BL6 mice. Full-thickness skin flap was made on dorsomedial back and re-sutured to evaluate the wound healing process. EDV was delivered slowly in the skin flap with degradable fibrin glue. The flap was monitored and analyzed on postoperative days 1, 3, and 5. CD31/DAPI staining was done to detect newly formed blood vessels. The expression levels of NF-κB, bcl-2, NOX3, and STAT3 proteins in C57BL6 mouse tissues were also examined. The wound healing process in hyper- and normoglycemic mice showed a difference in protein expression, especially in oxidative stress management and angiogenesis. Exogenous H2O2 reduced cell viability in a proportion to the concentration via apoptosis. EDV protected HaCaT cells and HDFs from H2O2 induced reactive oxygen species cell damage and apoptosis. In the mouse model, EDV with fibrin resulted in less necrotic areas and increased angiogenesis on postoperative day 5, compared to sham-treated mice. Our results indicate that EDV could protect H2O2-induced cellular injury via inhibiting early apoptosis and inflammation and also increasing angiogenesis. EDV might be valuable in the treatment of diabetic wounds that oxidative stress has been implicated.

Impact of donor and prolonged cold ischemia time of neonatal pig pancreas on neonatal pig islet transplant outcome.

Genetically modified pigs (GMP) have been developed to alleviate the shortage of donors in human islet transplantation and rejection. In this study, we characterized and compared the islets from GalTKO, GalTKO/hCD46, GalTKO/hCD46/hCD39, and wild-type (WT) neonatal pigs. Islets were isolated from GMP and WT pig pancreases that have been packaged with ice pack for at least 24hours. The difference in gene expression and function of islets were evaluated by microarray analysis and transplantation of islets under the kidney capsule of streptozotocin-induced diabetic immune-deficient mice, respectively. Blood glucose levels of these mice were monitored weekly post-transplantation for >100days, and islet grafts were collected and evaluated for the presence of endocrine cells. The genes involved in extracellular components, cell adhesion, glucose metabolism, and inflammatory response are differentially expressed between GMP and WT pig islets. Variation in the ability of pig islets in correcting the diabetic state of the mouse recipients appears to be dependent on the pig donor. In addition, prolonged cold ischemia time had a negative effect on the transplant outcome. All normoglycemic mice were able to respond well to glucose challenge despite the initial differences in the ability of islet transplants to reverse their diabetic state. Islet xenografts of normoglycemic mice contained abundant insulin- and glucagon-positive cells. The effect of GMP and WT neonatal pig islet transplants on hyperglycemia in mice appears to be dependent on the pig donor, and prolonged cold ischemia time negatively affects the neonatal pig islet transplant outcome.

Synergistic hypolipidemic and hypoglycemic effects of mixtures of Lactobacillus nagelii/betanin in a mouse model

Purpose: To determine the nutraceutical effect of mixtures containing Lactobacillus nagelii/betanin on the carbohydrate and lipid metabolism of mice.Methods: Lactobacillus nagelii and betanin were isolated from the raw materials. These components were subsequently assessed for their anti-hyperglycemic and hypolipidemic activities, and administered individually or combined in normoglycemic and diabetic mice. These animals were subjected to a standard OGTT and given an atherogenic diet.Results: The combination of L. nagelii (2.0 × 109 CFU/mL) and betanin (30 mg/kg body weight) exerted a significant (p &lt; 0.01) and prolonged reduction of postprandial blood glucose (30 - 120 min). Interestingly, a mixture of L. nagelii (1 ×107 CFU/mouse/day) with betanin (10 mg/kg body weight) administered for 30 days, produced favourable effects (p &lt; 0.01) in the lipid profile of mice previously treated with an atherogenic diet. These mixtures significantly ameliorated (p &lt; 0.01) hypoinsulinemia, hyperleptinemia and increased the levels of adiponectin.Conclusion: The simultaneous administration of L. nagelii and betanin in mice produced a beneficial change in blood glucose and lipids in mice, indicating a synergistic nutraceutical effect. However, there is a need to develop this therapy further for potential application in humans&#x0D; Keywords: Lactobacillus nagelii, Betanin, Anti-hyperglycemic, Hypolipidemic

Synthesis of drug conjugated magnetic nanocomposite with enhanced hypoglycemic effects

In the present study, a magnetic nanocomposite (magnetite Fe3O4 and hematite Fe2O3) has been successfully synthesized by the sol-gel method and coated with polyvinyl alcohol (PVA) followed by conjugation of anti-diabetic drug metformin. Detailed structural and microstructural characterization of the nanocomposite (NP) and drug conjugated nanocomposite (NP-DC) are analyzed by the Rietveld refinement of respective XRD patterns, FTIR analysis, UV–Vis spectroscopy, SEM and TEM results. SEM and TEM image analyses reveal the spherical morphology and average size of NP, PVA coated nanoparticles (NP-PVA) and NP-DC samples, indicating a suitable size to be a nanocarrier. The biocompatibility of NP and NP-DC was carried out in NIH/3T3 and J774A. 1 cells. The enhanced activity of the drug, when conjugated with nanocomposite, is confirmed after the treatment of both the pure drug and NP-DC sample on the 18 h fasted normoglycemic and hyperglycemic mice. The blood glucose level of the mice is effectively decreased with the same concentration of the pure drug and NP-DC sample. It proves the increased activity of the NP-DC sample, as only 5 wt% drug is present that shows the same efficiency as the pure drug. This study suggests excellent biocompatibility and cytocompatibility of NP and NP-DC besides the critical property as a hypoglycemic agent. It is the first time approach of conjugating metformin with a magnetic nanocomposite for a significant increment of its hypoglycemic activity, which is very important to reduce the side effect of metformin for its prolonged use.

Hypoglycemic, Anti-Hyperglycemic and Anti-Hyperlipidemic Effects of Bersama abyssinica Fresen (Melianthaceae) Leaves' Solvent Fractions in Normoglycemic and Streptozotocin-Induced Diabetic Mice.

BackgroundThe leaves of Bersama abyssinica are used by traditional healers and the community for the treatment of diabetes mellitus. Thus, the current study intended to evaluate the hypoglycemic, anti-diabetic, and anti-hyperlipidemic effects of Bersama abyssinica.MethodsThe solvent fractions of Bersama abyssinica leaves were prepared. A total of 132 healthy, male Swiss albino mice weighing 20–28 grams (age of 6–10 weeks) were used. The antidiabetic activity of all the doses (100, 200, and 400 mg/kg) of Bersama abyssinica solvent fractions was evaluated by animal models: normoglycemic mice, oral glucose loaded mice, and diabetic mice. Diabetes was induced by a single intraperitoneal injection of streptozotocin (150mg/kg body weight). The effect of the plant extract on body weight and serum lipid levels were measured in diabetic mice. Statistical analysis was performed by using statistical package for social sciences version 24. The analyses were carried out using one-way ANOVA, followed by Tukey’s multiple comparison tests. The result was considered significant when p <0.05.ResultsThe solvent fractions of B. abyssinica at all tested doses (100, 200, and 400 mg/kg) exhibited significant (P<0.05–0.001) BGL reduction in all animal models. In hypoglycemic activity, the percentage reduction of baseline BGL was 25.90%, 26.36%, 38.43%, 30.96% and 49.42% for EAF200mg/kg, AQF200mg/kg, EAF400mg/kg, AQF400mg/kg, and GLC 5mg/kg, respectively. B. abyssinica at the dose of AQF 200 mg/kg (p<0.05), AQF 400mg/kg (p<0.001), EAF 200mg/kg (p<0.01), and GLC 5mg/kg (p<0.001) significantly reduced the BGL following 1-hour post-treatment as compared to the negative control. Likewise, the higher doses of the solvent fractions (400mg/kg) significantly (p<0.001) reduced the BGL following 2- and 3-hours post-treatment as compared to the negative control. Daily administration of aqueous fraction of B. abyssinica caused a maximum reduction in fasting BGL at the fourteenth day of administration by 33.29%, 38.59%, 52.71%, and 59.66%, respectively, for AQF100, AQF200, AQF400, and GLC 5mg/kg. The aqueous fraction of B. abyssinica and the glibenclamide significantly (p<0.05) prevent loss of body weight and showed improvement in serum lipid levels.ConclusionThe solvent fractions of Bersama abyssinica exhibit noticeable antidiabetic activity in all animal models (normoglycemic mice, oral glucose loaded mice, and diabetic mice) and showed improvement in body weight and serum lipid profile levels, which rationalizes the claimed use of the B. abyssinica in the treatment of diabetes mellitus.

Metformin improves cognition of aged mice by promoting cerebral angiogenesis and neurogenesis.

Metformin is a widely used drug for type 2 diabetes that is considered to have potential anti-aging effects. However, the beneficial effects of metformin in middle-aged normoglycemic mice are less explored. Here, we report that metformin treated by tail vein injection improved cognitive function of aged mice better than oral administration, which seem to show a dose-dependent manner. Correspondingly, long-term oral administration of metformin was associated with significant disability rates. Further, metformin restored cerebral blood flow and brain vascular density and promoted neurogenic potential of the subependymal zone/subventricular zone both in vivo and in vitro. RNA-Seq and q-PCR results indicated that metformin could enhance relative mRNA glycolysis expression in blood and hippocampal tissue, respectively. Mechanistically, glyceraldehyde-3-phosphate dehydrogenase (GAPDH), a key enzyme in glycolysis pathway, may contribute to angiogenic and neurogenic potentials of NSCs. Interestingly, the relative GAPDH mRNA expression of peripheral blood mononuclear cell was gradually decreased with aging. Meanwhile its expression level positively correlated with cognitive levels. Our results indicated that metformin represents a candidate pharmacological approach for recruitment of NSCs in aged mouse brain by enhancing glycolysis and promoting neurovascular generation, a strategy that might be of therapeutic value for anti-aging in humans.

Pancreatic Alpha-Cells Contribute Together With Beta-Cells to CXCL10 Expression in Type 1 Diabetes.

C-X-C Motif Chemokine Ligand 10 (CXCL10) is a pro-inflammatory chemokine specifically recognized by the ligand receptor CXCR3 which is mostly expressed in T-lymphocytes. Although CXCL10 expression and secretion have been widely associated to pancreatic islets both in non-obese diabetic (NOD) mice and in human type 1 diabetic (T1D) donors, the specific expression pattern among pancreatic endocrine cell subtypes has not been clarified yet. Therefore, the purpose of this study was to shed light on the pancreatic islet expression of CXCL10 in NOD, in C57Bl/6J and in NOD-SCID mice as well as in human T1D pancreata from new-onset T1D patients (DiViD study) compared to non-diabetic multiorgan donors from the INNODIA European Network for Pancreatic Organ Donors with Diabetes (EUnPOD). CXCL10 was expressed in pancreatic islets of normoglycaemic and new-onset diabetic NOD mice but not in C57Bl/6J and NOD-SCID mice. CXCL10 expression was increased in pancreatic islets of new-onset diabetic NOD mice compared to normoglycaemic NOD mice. In NOD mice, CXCL10 colocalized both with insulin and glucagon. Interestingly, CXCL10-glucagon colocalization rate was significantly increased in diabetic vs. normoglycaemic NOD mouse islets, indicating an increased expression of CXCL10 also in alpha-cells. CXCL10 was expressed in pancreatic islets of T1D patients but not in non-diabetic donors. The analysis of the expression pattern of CXCL10 in human T1D pancreata from DiViD study, revealed an increased colocalization rate with glucagon compared to insulin. Of note, CXCL10 was also expressed in alpha-cells residing in insulin-deficient islets (IDI), suggesting that CXCL10 expression in alpha cells is not driven by residual beta-cells and therefore may represent an independent phenomenon. In conclusion, we show that in T1D CXCL10 is expressed by alpha-cells both in NOD mice and in T1D patients, thus pointing to an additional novel role for alpha-cells in T1D pathogenesis and progression.

In vivo and in vitro antidiabetic potential of Taraxacum officinale root extracts

Abstract Taraxacum officinale F.H. Wigg (Asteraceae) root is traditionally used to treat diabetes, dyspepsia, heartburn, anorexia and hepatitis. In this work, petroleum ether, chloroform, methanol and aqueous extracts of T. officinale root were evaluated for their antidiabetic activity in normoglycemic and alloxan-induced diabetic mice at two concentrations (200 and 400 mg/kg) using antidiabetic and subcutaneous glucose tolerance tests. Herein, in vitro glucose uptake assay was performed using HepG2 and 2-NDBG, while LC-MS/MS was employed for the phytochemical study of the main active constituents in the active extract. In the experiments, T. officinale root aqueous extract (400 mg/kg) showed a significant decrement in blood glucose level (62.33%, p ≤0.05), while other extracts (p &gt;0.05) showed insignificant activity – in alloxan-induced diabetic mice with no apparent effect on the normoglycemic model. The extracts also showed an insignificant reduction in glucose levels (p &gt;0.05) in the subcutaneous glucose tolerance test. However, a significant glucose uptake enhancement (149.6724%, p ≤0.05) was exhibited by the aqueous extract. Phytochemical study of the aqueous extract showed higher total phenolic than total flavonoid content, in which chlorogenic acid, protocatechuic acid, and luteolin-7-glucoside were identified.

Antihyperglycemic Effects of Annona diversifolia Safford and Its Acyclic Terpenoids: α-Glucosidase and Selective SGLT1 Inhibitiors.

Annona diversifolia Safford and two acyclic terpenoids were evaluated to determine their antihyperglycemic activity as potential α-glucosidase and selective SGLT-1 inhibitiors. Ethanolic extract (EEAd), chloroformic (CHCl3Fr), ethyl acetate (EtOAcFr), aqueous residual (AcRFr), secondary 5 (Fr5) fractions, farnesal (1), and farnesol (2) were evaluated on normoglycemic and streptozocin-induced diabetic mice. EEAd, CHCl3Fr, Fr5, (1) and (2) showed antihyperglycemic activity. The potential as α-glucosidase inhibitors of products was evaluated with oral sucrose and lactose tolerance (OSTT and OLTT, respectively) and intestinal sucrose hydrolysis (ISH) tests; the potential as SGLT-1 inhibitors was evaluated using oral glucose tolerance (OGTT), intestinal glucose absorption (IGA), and urinary glucose excretion (UGE) tests. In OSTT and OLTT, all treatments showed significant activity at two and four hours. In ISH, half maximal effective concentrations (CE50) of 565, 662 and 590 μg/mL, 682 and 802 μM were calculated, respectively. In OGTT, all treatments showed significant activity at two hours. In IGA, CE50 values of 1059, 783 and 539 μg/mL, 1211 and 327 μM were calculated, respectively. In UGE Fr5, (1) and (2) showed significant reduction of the glucose excreted compared with canagliflozin. These results suggest that the antihyperglycemic activity is mediated by α-glucosidase and selective SGLT-1 inhibition.

Endothelial Dysfunction and Passive Changes in the Aorta and Coronary Arteries of Diabetic db/db Mice.

Endothelial cell dysfunction and vessel stiffening are associated with a worsened prognosis in diabetic patients with cardiovascular diseases. The present study hypothesized that sex impacts endothelial dysfunction and structural changes in arteries from diabetic mice. In diabetic (db/db) and normoglycaemic (db/db+) mice, the mechanical properties were investigated in pressurized isolated left anterior descending coronary arteries and aorta segments that were subjected to tensile testing. Functional studies were performed on wire-mounted vascular segments. The male and female db/db mice were hyperglycaemic and had markedly increased body weight. In isolated aorta segments without the contribution of smooth muscle cells, load to rupture, viscoelasticity, and collagen content were decreased suggesting larger distensibility of the arterial wall in both male and female db/db mice. In male db/db aorta segments with smooth muscle cell contribution, lumen diameter was smaller and the passive stretch-tension curve was leftward-shifted, while they were unaltered in female db/db aorta segments versus control db/db+ mice. In contrast to female db/db mice, coronary arteries from male db/db mice had altered stress-strain relationships and increased distensibility. Transthoracic echocardiography revealed a dilated left ventricle with unaltered cardiac output, while aortic flow velocity was decreased in male db/db mice. Impairment of acetylcholine relaxation was aggravated in aorta from female db/db compared to control and male db/db mice, while impairment of sodium nitroprusside relaxations was only observed in aorta from male db/db mice. The remodeling in the coronary arteries and aorta suggests an adaptation of the arterial wall to the reduced flow velocity with sex-specific differences in the passive properties of aorta and coronary arteries. The findings of less distensible arteries and more pronounced endothelial dysfunction in female compared to male diabetic mice may have implications for the observed higher incidence of macrovascular complications in diabetic women.

Targeted nanoparticles towards increased L cell stimulation as a strategy to improve oral peptide delivery in incretin-based diabetes treatment

The delivery of therapeutic peptides via the oral route remains one of biggest challenges in the pharmaceutical industry. Recently, we have described an alternative improved drug delivery system for peptide delivery via the oral route, consisting of a lipidic nanocapsule. Despite the striking effects observed, it is still essential to develop strategies to strengthen the nanocarriers’ glucagon-like peptide-1 (GLP-1) secretory effect of the nanocarrier and/or prolong its antidiabetic effect in vivo to facilitate its translation into the clinic. For this purpose, we developed and compared different fatty acid-targeted lipid and polymeric nanoparticles and evaluated the L cell stimulation induced by the nanocarriers in murine L cells in vitro and in normal healthy mice in vivo. We further examined the antidiabetic effect in vivo in an obese/diabetic mouse model induced by high-fat diet feeding and examined the effect of the oral administration frequency. Among the tested nanocarriers, only lipid-based nanocarriers that were surface-modified with DSPE-PEG2000 on the surface were able to significantly strengthen the biological effect of the nanocarriers. They increased endogenous GLP-1 levels up to 8-fold in vivo in normoglycemic mice. Moreover, they effectively prolonged the in vivo antidiabetic effect by normalizing the plasma glucose levels in obese/diabetic mice following long-term treatment (one month). Ultimately, the targeted nanocarriers were as effective when the administration frequency was reduced from once daily to once every other day.