Trimethylamine N-oxide aggravates vascular permeability and endothelial cell dysfunction under diabetic condition:in vitro and in vivo study

AIM:To provide the direct evidence for the crucial role of trimethylamine N-oxide(TMAO)in vascular permeability and endothelial cell dysfunction under diabetic condition.METHODS:The role of TMAO on the in vitro biological effect of human retinal microvascular endothelial cells(HRMEC)under high glucose conditions was tested by a cell counting kit,wound healing,a transwell and a tube formation assay.The inflammation-related gene expression affected by TMAO was tested by real-time polymerase chain reaction(RT-PCR).The expression of the cell junction was measured by Western blotting(WB)and immunofluorescence staining.In addition,two groups of rat models,diabetic and non-diabetic,were fed with normal or 0.1%TMAO for 16wk,and their plasma levels of TMAO,vascular endothelial growth factor(VEGF),interleukin(IL)-6 and tumor necrosis factor(TNF)-αwere tested.The vascular permeability of rat retinas was measured using FITC-Dextran,and the expression of zonula occludens(ZO)-1 and claudin-5 in rat retinas was detected by WB or immunofluorescence staining.RESULTS:TMAO administration significantly increased the cell proliferation,migration,and tube formation of primary HRMEC either in normal or high-glucose conditions.RT-PCR showed elevated inflammation-related gene expression of HRMEC under TMAO stimulation,while WB or immunofluorescence staining indicated decreased cell junction ZO-1 and occludin expression after high-glucose and TMAO treatment.Diabetic rats showed higher plasma levels of TMAO as well as retinal vascular leakage,which were even higher in TMAO-feeding diabetic rats.Furthermore,TMAO administration increased the rat plasma levels of VEGF,IL-6 and TNF-αwhile decreasing the retinal expression levels of ZO-1 and claudin-5.CONCLUSION:TMAO enhances the proliferation,migration,and tube formation of HRMEC,as well as destroys their vascular integrity and tight connection.It also regulates the expression of VEGF,IL-6,and TNF-α.

Therapeutic effect of folic acid combined with decitabine on diabetic mice

AIM:To evaluate the therapeutic effect of folic acid combined with decitabine on diabetic mice.METHODS:The diabetic model of db/db mice were randomly divided into model group,folic acid group,decitabine group,folic acid combined with decitabine group,and C57 mice as normal control group.The density of retinal blood vessels and retinal thickness were detected by fundus photography and optical coherence tomography,respectively.Pathological changes of retina were observed by hematoxylin-eosin(HE)staining.The homocysteine(Hcy)in serum was detected by enzyme linked immunosorbent assay(ELISA).TdT-mediated dUTP nick-end labeling(TUNEL)was used to detect apoptosis in retinal tissue.Evans blue dye was used to detect the permeability of retinal blood vessels.The platelet endothelial cell adhesion molecule-1(CD31)and vascular endothelial growth factor receptor(VEGFR)protein were detected by Western blot.The 3-nitrotyrosine(3-NT)and 4-hydroxynonanine(4-HNE)were detected by immunohistochemistry.RESULTS:The density of retinal blood vessels,retinal thickness,retinal vascular permeability and the proportion of apoptotic cells of retinal tissue in the model group increased significantly than control group(P<0.05).The Hcy in serum and the levels of CD31,VEGFR,3-NT,and 4-HNE in retinal tissue increased significantly in the model group(P<0.01).Folic acid and decitabine both reversed these changes significantly,and the combination of the folic acid and decitabine worked best.CONCLUSION:The combination of folic acid and decitabine has a more significant protective effect on the retina in diabetic mice.

Effect of periocular injection of celecoxib and propranolol on ocular level of vascular endothelial growth factor in a diabetic mouse model

AIM： To investigate the effects of periocular injection of propranolol and celecoxib on ocular levels of vascular endothelial growth factor （VEGF） in a diabetic mouse model. METHODS： Forty 4-6wk BALB-C male mice weighing 20-25 g were used. The study groups included： nondiabetic control （group 1）, diabetic control （group 2）, diabetic propranolol （group 3）, and diabetic celecoxib （group 4）. After induction of type 1 diabetes by streptozotocin, propranolol （10 μg） and celecoxib （200 μg dissolved in carboxymethylcellulose 0.5%） were injected periocularly. The ocular level of VEGF was measured in all the study groups using enzyme-linked immuno sorbent assay （ELISA） method. RESULTS： Ocular VEGF level was significantly increased （1.25 fold） in the diabetic control group when compared to the non-diabetic group one week after induction with streptozotocin （P=0.002）. Both periocular propranolol and celecoxib significantly reduced ocular VEGF levels （P=0.047 and P〈0.001, respectively）. The effect was more pronounced with celecoxib, CONCLUSION： The periocular administration of propranolol and celecoxib can significantly reduce ocular VEGF levels in a diabetic mouse model.

Metabolite profiling and antidiabetic attributes of ultrasonicated leaf extracts of Conocarpus lancifolius

Objective:To profile the secondary metabolites and to evaluate the antidiabetic potential of hydroethanolic leaf extracts of Conocarpus lancifolius.Methods:The various hydroethanolic extracts of Conocarpus lancifolius leaf were prepared by ultrasonication assisted freezedrying.Total phenolic contents,flavonoid contents,antioxidant activity,α-glucosidase andα-amylase inhibitions of leaf extracts were determined.The metabolite profiling was accomplished by UHPLC-Q-TOF-MS/MS analysis.The antidiabetic assessment of the most potent extract was carried out by measuring the hypoglycemic and hypolipidemic effect in the high fat diet-fed diabetic albino mice.The blood glucose level,haemoglobin,total cholesterol,high-density lipoproteins(HDL)and low-density lipoproteins(LDL)were determined.Results:The 60%ethanolic extract exhibited the highest phenolic and flavonoid contents of(349.39±2.13)mg GAE/g dry extract and(116.95±2.34)mg RE/g dry extracts,respectively,and the highest DPPH scavenging activity with an IC50 value of(32.87±1.11)μg/mL.The IC50 values forα-glucosidase andα-amylase inhibitions were(38.64±0.93)μg/mL and(44.80±1.57)μg/mL,respectively.UHPLC-Q-TOF-MS/MS analysis confirmed the presence of gallic acid,ellagic acid,corilagin,kaempherol-3-O-rutinoside,caffeic acid derivative,isorhamnetin and galloyl derivatives in the 60%ethanolic extract.Plant extract at a dose of 450 mg/kg body weight reduced blood glucose level,total cholesterol,LDL and HDL,and increased haemoglobin in alloxan-induced diabetic mice,Conclusions:Conocarpus lancifolius leaves are proved as a good source of biologically functional metabolites and possess antidiabetic activity which may be further explored to treat diabetes.

Parsimonious Model for Blood Glucose Level Monitoring in Type 2 Diabetes patients

To establish the parsimonious model for blood glucose monitoring in patients with type 2 diabetes receiving oral hypoglycemic agent treatment. One hundred and fifty-nine adult Chinese type 2 diabetes patients were randomized to receive rapid-acting or sustained-release gliclazide therapy for 12 weeks.

ISLET FORMATION AND REGENERATION

Objective To explore the mechanisms of differentiation and development of pancreatic endocrine cells as well as pancreatic regeneration.Methods Human embryonic pancreatic tissue at 7-14 weeks of gestation was collected.Diabetes mellitus rat model was induced with 65 mg/kg of streptozotocin.Insulin, glucagon, somatostatin, nestin, and cytokeratin 19 (CK19) of pancreatic tissues were observed by immunohistochemistry.Results At 9 weeks of gestation, pancreatic epithelial cells began to co-express insulin, glucagon, somatostatin, and CK19 before migration.Islet cells gradually congregated along with the increase of aging, and at 14 weeks of gestation histological examination showed islet formation.At 12 weeks of gestation, nestin-positive cells could be seen in the pancreatic mesenchyme.During early embryogenesis, islet cells of pancreatic ducts co-expressed insulin, glucagon, and somatostatin.During pancreatic regeneration after damage, nestin expression of islet cells increased.Conclusion In the early stage of embryogenesis, islet cells of primary pancreatic ducts can be differentiated to multipotential endocrine cells before migration.During tissue regeneration, pancreatic stem cells may differentiate and proliferate to form pancreatic islet.

Controlled-release neurotensin-loaded silk fibroin dressings improve wound healing in diabetic rat model

Diabetic foot ulcers(DFU),which may lead to lower extremity amputation,is one of the severe and chronic complications of diabetic mellitus.This study aims to develop,and use dressings based on Silk fibroin(SF)as the scaffold material,gelatin microspheres(GMs)as the carrier for the neurotensin(NT),a neuropeptide that acts as an inflammatory modulator in wound healing and NT as accelerate wound healing drug to treat DFU.We evaluated the wound healing processes and neo-tissue formation in rat diabetic model by macroscopic observation,histological observation(H&E staining and Masson's trichrome staining)and immunofluorescence analysis at 3,7,14,21 and 28 post-operation days.Our results show that the NT/GMs/SF group performance the best not only in macroscopic healing and less scars in 28 post-operation days,but also in fibroblast accumulation in tissue granulation,collagen expression and deposition at the wound site.From release profiles,we can know the GMs are a good carrier for control release drugs.The SEM results shows that the NT/GMs/SF dressings have an average pore size are 40–80μm and a porosity of∼85%,this pore size is suit for wound healing regeneration.These results suggest that the NT/GMs/SF dressings may work as an effective support for control release NT to promote DFU wound healing.

Organ-specific alterations in circadian genes by vertical sleeve gastrectomy in an obese diabetic mouse model

Current therapies for obesity and related complications have been shown to have limited benefits,including unsatisfactory weight loss and poor metabolic improvement.With recent developments in bariatric surgery,promising advancements have been made in clinical and scientific research,particularly in the management of obesity and diabetes.Vertical sleeve gastrectomy(VSG)has become increasingly popular due to its safety,simplicity,

Hypoglycemic and Hypolipidemic Effects of Lycium barbarum Polysaccharide in Diabetic Rats

Objective To study the antidiabetic effects and the underlying molecular mechanisms of Lycium barbarum polysaccharide（LBP） and its DEAE cellulose elution fraction LBP-IV in diabetic rats induced by high fat diet（HFD） and streptozotocin（STZ）. Methods After ig administration of LBP-IV [50, 100, and 200 mg/（kg·d）] and LBP [100 mg/（kg·d）] once daily for consecutive 4 weeks to diabetic rats, the glucose and lipids in blood, m RNA expression of phosphoenolpyruvate carboxykinase（PEPCK）, sterol regulatory element binding-protein-1c（SREBP-1c）, and fatty acid synthase（FAS） in liver were determined. Results Ig administration of LBP and LBP-IV significantly decreased the levels of blood glucose, Hb A1 c, TC, TG, and LDL-C, as well as the hepatic m RNA expression of PEPCK, SREBP-1c, and FAS, whereas significantly increased the oral glucose tolerance of diabetic rats. Conclusion The findings suggest that the antidiabetic effects of LBP and LBP-IV are associated with the decreased hepatic m RNA expression of PEPCK, SREBP-1c, and FAS in HFD-STZ induced diabetic rats.

Effects of timely insulin treatment on protection of β cells in a rat model of type 2 diabetes mellitus

Background Insulin treatment plays a key role in management of diabetes mellitus. Clinical researches showed that extra improvements in restoration of insulin secretion of pancreatic β cells were found in patients with newly diagnosed type 2 diabetes. The purpose of this study was to investigate the effects of early insulin treatment on insulin mRNA expression and morphological alterations of β cells in a Sprague Dawley (SD) rat model of type 2 diabetes. Methods A rat model of type 2 diabetes mellitus (T2DM) was induced by a high fat diet (high energy, HE) and low doses of streptozotoxin (STZ, 40 mg/kg). A group of diabetic rats was then injected with protamine zinc insulin (PZI, 1-2 U·kg -1·d -1) for one week. Insulin mRNA expression, morphological features of pancreatic islets, and metabolic parameters were examined in rats using reverse transcriptase-polymerase chain reaction (RT-PCR), immunohistochemistry, and other techniques. Results In insulin-treated diabetic rats, insulin mRNA levels prominently increased by 81.3% (P<0.05), as compared with untreated diabetic rats. Moreover, timely insulin treatment noticeably improved the insulin content of β cells, with an increase of 10.2% (P<0.05), despite a slight reduction in fasting blood glucose (FBG), triglyceride (TG), and free fatty acid (FFA) levels, as compared to an untreated diabetic group. Conclusion Insulin treatment at the onset of T2DM effectively improves insulin synthesis, as confirmed by morphological changes to β cells in a rat model of type 2 diabetes.

Distinctive quality control method for solid-state fermented Isaria cicadae from strain Ic-17-7 and application in a rat model of type 2 diabetes

This work was aimed to establish a quality control method for evaluating the effects on glucose and lipids of the fruiting body of Isaria cicadae Miquel from strain Ic-17-7(Ic-17-7fb) using a rat model of type 2 diabetes(T2DM). Random amplified polymorphic DNA, sequence-characterized amplified region, and high-performance liquid chromatography(HPLC) were used for the quality control of Ic-17-7fb. The pharmacological effects on streptozocin(STZ)-induced high fat diet(HFD)-fed Albino Wistar rats were evaluated. The rats underwent the following treatments: control, metformin, Ic-17-7fb(0.166 and 0.5 g·kg;) or without treatment. The fasting blood glucose(FBG), blood glucose, total cholesterol(TC), triglyceride(TG), high-density lipoprotein(HDL-c), and low-density lipoprotein(LDL-c) were measured. Ic-17-7fb amplified a single specific band by S11-2-F3 and S11-2-R3 primers. An HPLC-based quality and quantity method was established for industrial application. The contents of adenosine and N;-(2-hydroxyethyl) adenosine(HEA) of the cultivated Ic-17-7fb were analyzed. All of the validation lots of cultured Ic-17-7fb passed the quantity control of the training set(0.90 mg·g;of adenosine and 0.89 mg·g;of HEA). After two weeks of administration, the average FBG was 4.89 ± 0.42(control), 26.10 ± 5.77(model), 23.63 ± 6.15(metformin), 17.96 ± 9.36(Ic-17-7fb for 0.166 g·kg;), and 19.69 ±8.71 mmol·L;(Ic-17-7fb for 0.5 g·kg;). The FBG of Ic-17-7fb(0.166 g·kg;) treatment significantly reduced by 31.19%, compared with the model after two weeks of administration(P < 0.01). Metformin, Ic-17-7fb(0.166 g·kg;), and Ic-17-7fb(0.5 g·kg;) reduced TC, TG, HDL-c, and LDL-c compared with the T2DM model treatment at the 6 th week of treatment(P < 0.05). This study established the first quality standard for Ic-17-7fb, which can be effectively applied in the treatment of T2DM. The reliable quality control method and pharmacological effect will broaden its application space.