Effects of vitamin D supplementation on glucose and lipid metabolism in patients with type 2 diabetes mellitus and risk factors for insulin resistance

BACKGROUND Type 2 diabetes mellitus(T2DM)is a chronic metabolic disease featured by insulin resistance(IR)and decreased insulin secretion.Currently,vitamin D deficiency is found in most patients with T2DM,but the relationship between vitamin D and IR in T2DM patients requires further investigation.AIM To explore the risk factors of IR and the effects of vitamin D supplementation on glucose and lipid metabolism in patients with T2DM.METHODS Clinical data of 162 T2DM patients treated in First Affiliated Hospital of Harbin Medical University between January 2019 and February 2022 were retrospectively analyzed.Based on the diagnostic criteria of IR,the patients were divided into a resistance group(n=100)and a non-resistance group(n=62).Subsequently,patients in the resistance group were subdivided to a conventional group(n=44)or a joint group(n=56)according to the treatment regimens.Logistic regression was carried out to analyze the risk factors of IR in T2DM patients.The changes in glucose and lipid metabolism indexes in T2DM patients with vitamin D deficiency were evaluated after the treatment.RESULTS Notable differences were observed in age and body mass index(BMI)between the resistance group and the non-resistance group(both P<0.05).The resistance group exhibited a lower 25-hydroxyvitamin D_(3)(25(OH)D_(3))level,as well as notably higher levels of 2-h postprandial blood glucose(2hPG),fasting blood glucose(FBG),and glycosylated hemoglobin(HbA1c)than the non-resistance group(all P<0.0001).Additionally,the resistance group demonstrated a higher triglyceride(TG)level but a lower high-density lipoprotein-cholesterol(HDL-C)level than the non-resistance group(all P<0.0001).The BMI,TG,HDL-C,25(OH)D_(3),2hPG,and HbA1c were found to be risk factors of IR.Moreover,the posttreatment changes in levels of 25(OH)D_(3),2hPG,FBG and HbA1c,as well as TG,total cholesterol,and HDL-C in the joint group were more significant than those in the conventional group(all P<0.05).CONCLUSION Patients with IR exhibit significant abnormalities in glucose and lipid metabolism parameters compared to the noninsulin resistant group.Logistic regression analysis revealed that 25(OH)D_(3)is an independent risk factor influencing IR.Supplementation of vitamin D has been shown to improve glucose and lipid metabolism in patients with IR and T2DM.

Anti-and non-tumor necrosis factor-α-targeted therapies effects on insulin resistance in rheumatoid arthritis,psoriatic arthritis and ankylosing spondylitis

In addition toβ-cell failure with inadequate insulin secretion,the crucial mechanism leading to establishment of diabetes mellitus(DM)is the resistance of target cells to insulin,i.e.insulin resistance(IR),indicating a requirement of beyond-normal insulin concentrations to maintain euglycemic status and an ineffective strength of transduction signaling from the receptor,downstream to the substrates of insulin action.IR is a common feature of most metabolic disorders,particularly type II DM as well as some cases of type I DM.A variety of human inammatory disorders with increased levels of proinflammatory cytokines,including tumor necrosis factor(TNF)-α,interleukin(IL)-6 and IL-1β,have been reported to be associated with an increased risk of IR.Autoimmunemediated arthritis conditions,including rheumatoid arthritis(RA),psoriatic arthritis(PsA)and ankylosing spondylitis(AS),with the involvement of proinflammatory cytokines as their central pathogenesis,have been demonstrated to be associated with IR,especially during the active disease state.There is an increasing trend towards using biologic agents and small molecule-targeted drugs to treat such disorders.In this review,we focus on the effects of anti-TNF-α-and non-TNF-α-targeted therapies on IR in patients with RA,PsA and AS.Anti-TNF-αtherapy,IL-1 blockade,IL-6 antagonist,Janus kinase inhibitor and phosphodiesterase type 4 blocker can reduce IR and improve diabetic hyper-glycemia in autoimmune-mediated arthritis.

Effects of insulin aspart and metformin on gestational diabetes mellitus and inflammatory markers

BACKGROUND Gestational diabetes mellitus(GDM)refers to hyperglycemia caused by insulin resistance or insufficient insulin secretion during pregnancy.Patients with GDM have a high risk of pregnancy complications,which can adversely affect both maternal and fetal health.Therefore,early diagnosis,treatment and monitoring of GDM are essential.In recent years,a new treatment scheme represented by insulin aspart combined with metformin has received increasing attention.AIM To explore the effects of insulin aspart combined with metformin on patients with GDM and inflammatory markers.METHODS From April 2020 to September 2022,124 patients with GDM in Sanya Women and Children’s Hospital Managed by Shanghai Children’s Medical Center were collected and analyzed retrospectively.The control group(CG)comprised 62 patients treated with insulin aspart alone,and 62 patients treated with insulin aspart and metformin formed the observation group(OG).Before and after treatment,improvement of blood-glucose-related indexes[fasting blood glucose(FBG),2-h postprandial glucose(2h PG)and hemoglobin A1c(HbA1c)],serum related factor[serum homocysteine(Hcy)],serum inflammatory cytokines[tumor necrosis factor(TNF)-α,interleukin(IL)-6 and C-reactive protein(CRP)]were compared between the two groups.The clinical efficacy,adverse pregnancy outcomes and incidence of pregnancy complications were compared between the two groups.RESULTS After treatment,the levels of FBG,2h PG,HbA1c,Hcy,TNF-α,IL-6 and CRP in both groups were significantly decreased(P<0.05),and the levels of FBG,2h PG,HbA1c,Hcy,TNF-α,IL-6 and CRP in the OG were lower than in the CG(P<0.05).The total clinical effectiveness in the OG was higher than that in the CG(P<0.05).The total incidence of adverse pregnancy outcomes and complications in the OG was significantly lower than in the CG(P<0.05).CONCLUSION Insulin aspart combined with metformin are effective for treatment of GDM,which can reduce blood-glucoserelated indexes,Hcy and serum inflammatory cytokines,and risk of adverse pregnancy outcomes and complications.

Tumor necrosis factor alpha receptor 1 deficiency in hepatocytes does not protect from non-alcoholic steatohepatitis, but attenuates insulin resistance in mice

BACKGROUND End-stage liver disease caused by non-alcoholic steatohepatitis(NASH)is the second leading indication for liver transplantation.To date,only moderately effective pharmacotherapies exist to treat NASH.Understanding the pathogenesis of NASH is therefore crucial for the development of new therapies.The inflammatory cytokine tumor necrosis factor alpha(TNF-α)is important for the progression of liver disease.TNF signaling via TNF receptor 1(TNFR1)has been hypothesized to be important for the development of NASH and hepatocellular carcinoma in whole-body knockout animal models.AIM To investigate the role of TNFR1 signaling in hepatocytes for steatohepatitis development in a mouse model of diet-induced NASH.METHODS NASH was induced by a western-style fast-food diet in mice deficient for TNFR1 in hepatocytes(TNFR1ΔHEP)and their wild-type littermates(TNFR1fl/fl).Glucose tolerance was assessed after 18 wk and insulin resistance after 19 wk of feeding.After 20 wk mice were assessed for features of NASH and the metabolic syndrome such as liver weight,liver steatosis,liver fibrosis and markers of liver inflammation.RESULTS Obesity,liver injury,inflammation,steatosis and fibrosis was not different between TNFR1ΔHEP and TNFR1fl/fl mice.However,Tnfr1 deficiency in hepatocytes protected against glucose intolerance and insulin resistance.CONCLUSION Our results indicate that deficiency of TNFR1 signaling in hepatocytes does not protect from diet-induced NASH.However,improved insulin resistance in this model strengthens the role of the liver in glucose homeostasis.

Relationship between DEXA bone mineral density measurement results and serum cytokines as well as insulin resistance in patients with type 2 diabetes mellitus and osteoporosis

Objective:To study the relationship between DEXA bone mineral density measurement results and serum cytokines as well as insulin resistance in patients with type 2 diabetes mellitus and osteoporosis.Methods:Patients newly diagnosed with type 2 diabetes were selected and divided into normal bone mass group, osteopenia group and osteoporosis group according to the DEXA femoral neck bone mineral density measurement results, the bone mineral density of all parts in of three groups of patients were measured, and serum was collected to determine the levels of bone metabolism indexes, cytokines and insulin.Results:Femoral trochanter, Ward's area as well as the 2-4th lumbar vertebra bone mineral density values of osteopenia group and osteoporosis group were significantly lower than those of normal bone mass group, and the femoral trochanter, Ward's area as well as the 2-4th lumbar vertebra bone mineral density values of osteoporosis group were significantly lower than those of osteopenia group;serum N-MID, PINP and BGP levels of osteopenia group and osteoporosis group were significantly lower than those of normal bone mass group whileβ-CTX, TRACP5b, Ins, Chemerin, TNF-α, IL-1β and MCP-1 levels were significantly higher than those of normal bone mass group;serum N-MID, PINP and BGP levels of osteoporosis group were significantly lower than those of osteopenia group whileβ-CTX, TRACP5b, Ins, Chemerin, TNF-α, IL-1β and MCP-1 levels were significantly higher than those of osteopenia group;serum Ins, Chemerin, TNF-α, IL-1β and MCP-1 levels were negatively correlated with N-MID, PIN and BGP levels, and positively correlated with serumβ-CTX and TRACP5b levels.Conclusion:Excessively synthesized inflammatory factors and compensatory hyperinsulinemia in patients with type 2 diabetes mellitus and osteoporosis can promote bone resorption and inhibit bone formation, thus resulting in the osteopenia in multiple areas of the body.

Challenges and pitfalls of youth-onset type 2 diabetes

The incidence and prevalence of youth-onset type 2 diabetes mellitus(T2DM)are increasing.The rise in frequency and severity of childhood obesity,inclination to sedentary lifestyle,and epigenetic risks related to prenatal hyperglycemia exposure are important drivers of the youth-onset T2DM epidemic and might as well be responsible for the early onset of diabetes complications.Indeed,youth-onset T2DM has a more extreme metabolic phenotype than adult-onset T2DM,with greater insulin resistance and more rapid deterioration of beta cell function.Therefore,intermediate complications such as microalbuminuria develop in late childhood or early adulthood,while end-stage complications develop in mid-life.Due to the lack of efficacy and safety data,several drugs available for the treatment of adults with T2DM have not been approved in youth,reducing the pharmacological treatment options.In this mini review,we will try to address the present challenges and pitfalls related to youth-onset T2DM and summarize the available interventions to mitigate the risk of microvascular and macrovascular complications.

Biomolecular basis of the role of diabetes mellitus in osteoporosis and bone fractures

Osteoporosis has become a serious health problem throughout the world which is associated with an increased risk of bone fractures and mortality among the people of middle to old ages.Diabetes is also a major health problem among the people of all age ranges and the sufferers due to this abnormality increasing day by day.The aim of this review is to summarize the possible mechanisms through which diabetes may induce osteoporosis.Diabetes mellitus generally exerts its effect on different parts of the body including bone cells specially the osteoblast and osteoclast,muscles,retina of the eyes,adipose tissue,endocrine system specially parathyroid hormone(PTH) and estrogen,cytokines,nervous system and digestive system.Diabetes negatively regulates osteoblast differentiation and function while positively regulates osteoclast differentiation and function through the regulation of different intermediate factors and thereby decreases bone formation while increases bone resorption.Some factors such as diabetic neuropathy,reactive oxygen species,Vitamin D,PTH have their effects on muscle cells.Diabetes decreases the muscle strength through regulating these factors in various ways and ultimately increases the risk of fall that may cause bone fractures.

Elevated alanine aminotransferase activity is not associated with dyslipidemias,but related to insulin resistance and higher disease grades in non-diabetic non-alcoholic fatty liver disease

Objective:To explore demographic and metabolic factors associated with increased alanine aminotransferase(ALT)activity in non-diabetic non-alcoholic fatty liver disease(NAFLD)patients.Methods:Overall 372 patients who consecutively attended to Gastroenterology Clinic of Baqiyatallah University of Medical Sciences,Tehran,Iran awere diagnosed as NAFLD entered into analysis.Exclusion criteria were having diabetes mellitus and fasting blood glucose over126 mg/dL,active hepatitis B virus infection,having hepatitis C virus positive serology,and to be under corticosteroid therapy.ALT levels were considered pathologically high when it was over30 IU/L for men and over 19 IU/L for women.Results:Bivariate analyses using t test and chisquare test showed that patients with pathologically augmented ALT levels had significantly higher NAFLD grades in their ultrasonographic evaluations(P=0.003).Moreover,these patients represented significantly higher homeostatic model assessment levels(P=0.003),levels of serum insulin(P=0.002),fasting blood glucose(P<0.001),and uric acid(P=0.02).The prevalence of insulin resistance was also higher in patients with increased serum ALT concentrations.Multifactorial logistic regression models showed that ultrasonographic grading of NAFLD(P=0.027)and insulin resistance(P=0.013)were the only variables significantly associated with abnormal ALT levels.Conclusions:This study shows that the associations of increased ALT serum levels in NAFLD patients are different from what are supposed before.By excluding diabetic patients from our population,we find that increased ALT levels are not associated with dyslipidemias but are independently associated with insulin resistance and NAFLD grading on ultrasonographic evaluations.Further studies are needed to confirm our results.

Tum or Necrosis Factor Expression in ArterialWallsof Diabetic Rats

Immunohistochemistry was used to detect tumor necrosis factor (TNF α) expression in arterial wall of diabetic rats. It was found that endothelial cells were swollen and markedly proliferative in these vessels and accordingly TNF α showed strong positive immunohistochemical reaction in endothelial cells or extracellular intimal matrix of such vessels, which might be caused by the expression and release of TNF α from monocytes and arterial wall cells stimulated by AGEs. These findings suggested that increased TNF α expression might be associated with vascular damage and remodeling in diabetes.

Research progress on etiology of gestational diabetes mellitus

As a metabolic disorder during pregnancy,gestational diabetes mellitus (GDM) has an important effects on fetal development,neonatal health and maternal long-term health,and is one of the pregnancy complications with high incidence.It is of great significance that we have an accurate understanding of the etiology and risk factors of GDM for its prevention and control.GDM is a complex disease with multiple etiologies.Current studies have shown that the occurrence of GDM may be the result of combined effect of heredity and environment,but the exact etiology is still unclear.In this paper,we summarized the possible etiologies and risk factors of GDM,so as to understand the occurrence and development of GDM better and to provide possible references for prevention and further etiological studies of GDM.

New role for ceramide in hypoxia and insulin resistance

Ceramides are significant metabolic products of sphingolipids in lipid metabolism and are associated with insulin resistance and hepatic steatosis. In chronic inflammatory pathological conditions, hypoxia occurs, the metabolism of ceramide changes, and insulin resistance arises. Hypoxia-inducible factors(HIFs)are a family of transcription factors activated by hypoxia. In hypoxic adipocytes,HIF-1α upregulates pla2 g16(a novel HIF-1α target gene) gene expression to activate the NLRP3 inflammasome pathway and stimulate insulin resistance, and adipocyte-specific Hif1 a knockout can ameliorate homocysteine-induced insulin resistance in mice. The study on the HIF-2α-NEU3-ceramide pathway also reveals the role of ceramide in hypoxia and insulin resistance in obese mice.Under obesity-induced intestinal hypoxia, HIF-2α increases the production of ceramide by promoting the expression of the gene Neu3 encoding sialidase 3,which is a key enzyme in ceramide synthesis, resulting in insulin resistance in high-fat diet-induced obese mice. Moreover, genetic and pathophysiologic inhibition of the HIF-2α-NEU3-ceramide pathway can alleviate insulin resistance, suggesting that these could be potential drug targets for the treatment of metabolic diseases. Herein, the effects of hypoxia and ceramide, especially in the intestine, on metabolic diseases are summarized.

Variations of tumor necrosis factor-α, leptin and adiponectin in mid-trimester of gestational diabetes mellitus

Background Many cytokines have been found to increase the insulin resistance during pregnancy complicated by glucose metabolism disorder. This study aimed to investigate which comes first, the changes of some cytokines or the abnormal glucose metabolism. Methods This nested case-control study was undertaken from January 2004 to March 2005. Twenty-two women with gestational diabetes mellitus （GDM）, 10 with gestational impaired glucose tolerance （GIGT）, and 20 healthy pregnant women were chosen from the women who had visited the antenatal clinics and had blood samples prospectively taken and kept during their visit. The levels of tumor necrosis factor-α （TNF-α）, leptin and adiponectin were determined. One-way ANOVA analysis and bivariate correlation analysis were used to assess the laboratory results and their relationship with body mass index （BMI）. Results Women with GDM have the highest values of TNF-α and leptin and the lowest value of adiponectin compared with those with GIGT and the healthy controls （P 〈0.01） at 14-20 weeks of gestation. This was also found when these women progressed to 24-32 weeks. The significantly increased levels of TNF-α and leptin and the decreased level of adiponectin were found at the different periods of gestation within the same group. Positive correlation was shown between the levels of TNF-α and leptin at the two periods of gestation with the BMI at 14-20 weeks, while adiponectin was negatively correlated （P 〈0.05）. Conclusions The concentrations of TNF-α, leptin and adiponectin may change before the appearance of the abnormal glucose level during pregnancy. Further studies are required to verify the mechanism of this alteration and whether the three cytokines can be predictors for GDM at an early staqe of preqnancy.

Reduction of Insulin Resistance in HepG2 Cells by Knockdown of LITAF Expression in Human THP-1 Macrophages

The molecular mechanism by which obesity induces insulin resistance is not completely understood.The aim of this study was to determine how lipopolysaccharide-induced tumor necrosis-α factor (LITAF) influenced obesity-induced insulin resistance using a cellular co-culture system.The cells were divided into 3 groups:palmitic acid (PA) stimulation group,LITAF small interfering RNA (siRNA) group and untreated (NC) group.The LITAF siRNA was used for knockdown of LITAF ex-pression in human THP-1 macrophages.The expression levels of LITAF,IRS-2,IRS-2Tyr465,PI3K,and GLUT2 in each group were measured by using quantitative reverse transcriptase real-time poly-merase chain reaction and Western blotting.The expression of LITAF was much higher in the PA group than in the siRNA and NC groups (P<0.05);meanwhile,the expression of IRS-2,IRS-2Tyr465,PI3K,and GLUT2 was much lower in the PA group than in the NC group (P<0.05);however,IRS-2,IRS-2Tyr465,PI3K,and GLUT2 had much higher expression in the siRNA group than in the PA group (P<0.05).It is concluded that PA can induce insulin resistance in liver cells and knockdown of LITAF expression can reduce insulin resistance in liver cells,suggesting LITAF may regulate the insulin signal transduction pathway involved in obesity-induced insulin resistance.

Expression of matrix metalloproteinase-11 is increased under conditions of insulin resistance

AIM To investigate matrix metalloproteinase-11(MMP-11) expression in adipose tissue dysfunction, using in vitro and in vivo models of insulin resistance.METHODS Culture of mouse 3T3-L1 preadipocytes were induced to differentiation into mature 3T3-L1 adipocytes. Cellular insulin resistance was induced by treating differentiated cultured adipocytes with hypoxia and/or tumor necrosis factor(TNF)-α, and transcriptional changes were analyzed in each condition thereafter. For the in vivo studies, MMP-11 expression levels were measured in white adipose tissue(WAT) from C57BL/6J mice that underwent low fat diet or high-fat feeding in order to induce obesity and obesity-related insulin resistance. Statistical analysis was carried out with GraphP ad Prism Software.RESULTS MMP-11 m RNA expression levels were significantly higher in insulin resistant 3T3-L1 adipocytes compared to control cells(1.46±0.49vs0.83±0.21, respectively;P<0.00036). The increase in MMP-11 expression was observed even in the presence of TNF-α alone(3.79±1.11vs1±0.17, P<0.01) or hypoxia alone(1.79±0.7vs0.88±0.1, P<0.00023). The results obtained in in vitro experiments were confirmed in the in vivo model of insulin resistance. In particular, MMP-11 m RNA was upregulated in WAT from obese mice compared to lean mice(5.5±2.8vs1.1±0.7, respectively; P<3.72E-08). The increase in MMP-11 levels in obese mice was accompanied by the increase in typical markers of fibrosis, such as collagen type Ⅵ alpha 3(Col6_α3), and fibroblast-specific protein 1.CONCLUSION Our results indicate that dysregulation of MMP-11 expression is an early process in the adipose tissue dysfunction, which leads to obesity and obesity-related insulin resistance.

Pathophysiology of insulin resistance and steatosis in patients with chronic viral hepatitis

Chronic hepatitis due to any cause leads to cirrhosis and end-stage liver disease.A growing body of literature has also shown that fatty liver due to overweight or obesity is a leading cause of cirrhosis.Due to the obesity epidemic,fatty liver is now a significant problem in clinical practice.Steatosis has an impact on the acceleration of liver damage in patients with chronic hepatitis due to other causes.An association between hepatitis C virus (HCV) infection,steatosis and the onset of insulin resistance has been reported.Insulin resistance is one of the leading factors for severe fibrosis in chronic HCV infections.Moreover,hyperinsulinemia has a deleterious effect on the management of chronic HCV.Response to therapy is increased by decreasing insulin resistance by weight loss or the use of thiazolidenediones or metformin.The underlying mechanisms of this complex interaction are not fully understood.A direct cytopathic effect of HCV has been suggested.The genomic structure of HCV (suggesting that some viral sequences are involved in the intracellular accumulation of triglycerides),lipid metabolism,the molecular links between the HCV core protein and lipid droplets (the core protein of HCV and its transcriptional regulatory function which induce a triglyceride accumulation in hepatocytes) and increased neolipogenesis and inhibited fatty acid degradation in mitochondria have been investigated.

Functional imaging of skeletal muscle glucose metabolism by ¹⁸FDG PET to characterize insulin resistance in patients at high risk for coronary artery disease

Insulin resistance is associated with several coronary risk factors and is thought to play a critical role for the development of coronary artery disease. Insulin resistance has several causes, including an impaired skeletal muscle glucose utilization rate (SMGU), reduced peripheral blood flow, and altered fatty tissue metabolism, with SMGU being considered the most important. Nonetheless, insulin resistance has only been estimated by the glucose disposal rate (GDR) in previous studies. Methods: Skeletal muscle metabolic imaging with 18FDG and positron emission tomography (PET) was undertaken to measure SMGU during hyperinsulinemiceuglycemic clamping in 22 normotensive type-2 diabetics under no medications (T2- DM), 17 normotensive non-diabetic hypertriglyceridemics, 22 patients with hypertension, and 12 agematched controls. Whole body insulin resistance was assessed by the GDR during hyperinsulinemiceuglycemic insulin clamping. Results: The SMGU and GDR were significantly reduced in T2DM (32.1 ± 16.6 μmol/min/kg and 24.3 ± 13.0 μmol/min/kg, respectively), hypertriglyceridemics (36.5 ± 13.5 μmol/min/ kg and 22.7 ± 8.07 μmol/min/kg respectively) and patients with hypertension (35.4 ± 26.6 μmol/min/kg and 29.0 ± 9.90 μmol/min/kg, respectively) compared with controls (72.2 ± 44.1 μmol/min/kg and 43.0 ± 22.9 μmol/min/kg, p < 0.01, respectively). In all groups studied, SMGU was significantly correlated with GDR (r = 0.76, p < 0.01) and GDR (F = 13.9) was independently related to SMGU (r = 0.81, p < 0.01). Conclusion: Insulin resistance is significantly associated with SMGU to a similar degree among patients with T2DM, essential hypertension and hypertriglyceridemia. 18FDG PET functional imaging allows insulin resistance to be assessed.

Effects of Puerarin on Plasma Endothelin and Serum Tumor Necrosis Factor-α in Type 2 Diabetes Mellitus Patients with Vascular Complications

Objective: To study the changes of endothelin (ET), tumor necrosis factor-α (TNF-α) before and after puerarin treatment in patients with diabetes mellitus vascular complications (DMVC). Methods: Ninety-eight DMVC patients were divided into 2 groups, they were given puerarin (n=68) and normal saline (n=30) respectively, 20 diabetic patients without vascular complications (NDMVC) were taken as control, who were also given puerarin. All the patients were treated on the basis of controlling blood glucose. Plasma ET and serum TNF-α were determined by radioimmunoassay (RIA) before and after treatment. Results: Plasma ET and serum TNF-α in DMVC got higher than that of NDMVC patients (P<0.05), and ET level was correlated with TNF-α (r=0.69, r=0.73, P<0.01). After treatment, the levels of ET and TNF-α were significantly lower than those before treatment of DMVC patients with puerarin (P<0.05). Conclusion: Puerarin could regulate the levels of plasma ET and serum TNF-α of DMVC patients, suggesting that it has the function of regulating endothelial cells.

Prevention of Tumor Necrosis Factor-α Induced Insulin Resistance by Radix Astragali

Objective: To investigate the preventive effect of Radix Astragali on tumor necrosis factor-α(TNF-α). induced insulin resistance. Methods: Rats were treated orally with Radix Astragali before TNF-α intravenous injection. The changes of K value in glucose-insulin tolerance test, the concentrations of glucagon(GC), ACTH and lipids in serum and the contents of glycogen, triglyceride (TG) in liver and red quadricepswere tested 4 hours after the injection and compared with the control. Results: Exogenous TNF-α can inducehyperinsulinemia in normal rats, and the K value decreased, the concentration of serum ACTH, GC and lipidsall increased, the glycogen contents in liver and red quadriceps muscle decreased, and the liver TG depots increased. Radix Astragali can improve all the parameters significantly except the serum lipids level and livertriglyceride dePOts. Conclusions: Radix Astragali has preventive effect on insulin resistance induced by TNF-αand is useful in the treatment of type 2 diabetes. The mechanism may be due to the decrease of insulin-antagonistic hormones and the increase of tissue glycogen contents.

Dual therapy of rosiglitazone/pioglitazone with glimepiride on diabetic nephropathy in experimentally induced type 2 diabetes rats

Diabetic nephropathy is a major cause of end-stage renal disease （ESRD） in the general population. It is estimated that diabetic nephropathy will eventually develop in about 40% of all patients with diabetes; therefore, prevention is critical for delaying the development and progression of diabetic kidney disease. Despite extensive efforts, medical advances are still not successful enough to prevent the progression of the disease. In the present study, we focused on the comparison of combination therapies and whether they offered additional renoprotection. Type 2 diabetes mellitus was induced by intraperitoneally administering streptozotocin （90 mg/kg） in neonatal rats and then these rats were treated with rosiglitazone （1.0 mg/kg） in combination with glimepiride （0.5 mg/kg） or with pioglitazone （2.5 mg/kg） in combination with glimepiride （0.5 mg/kg）. Diabetic nephropathy markers were evaluated by biochemical and ELISA kits and renal structural changes were examined by light microscopy and transmission electron microscopy. Results show that the combination of pioglitazone with glimepiride is more effective in amelioration of diabetic nephropathy than rosiglitazone with glimepiride drug therapy due to glycemic control, suppressing albumin excretion rate, total protein excretion rate and augmented TNF-α signaling during the development of streptozotocin induced type 2 diabetic nephropathy.

Gut region-specific TNFR expression:TNFR2 is more affected than TNFR1 in duodenal myenteric ganglia of diabetic rats

BACKGROUND Cytokines are essential in autoimmune inflammatory processes that accompany type 1 diabetes.Tumor necrosis factor alpha plays a key role among others in modulating enteric neuroinflammation,however,it has a dual role in cell degeneration or survival depending on different TNFRs.In general,TNFR1 is believed to trigger apoptosis,while TNFR2 promotes cell regeneration.The importance of the neuronal microenvironment has been recently highlighted in gut region-specific diabetic enteric neuropathy,however,the expression and alterations of different TNFRs in the gastrointestinal tract has not been reported.AIM To investigate the TNFR1 and TNFR2 expression in myenteric ganglia and their environment in different intestinal segments of diabetic rats.METHODS Ten weeks after the onset of hyperglycemia,gut segments were taken from the duodenum,ileum and colon of streptozotocin-induced(60 mg/body weight kg i.p.)diabetic(n=17),insulin-treated diabetic(n=15)and sex-and age-matched control(n=15)rats.Myenteric plexus whole-mount preparations were prepared from different gut regions for TNFR1/HuCD or TNFR2/HuCD double-labeling fluorescent immunohistochemistry.TNFR1 and TNFR2 expression was evaluated by post-embedding immunogold electron microscopy on ultrathin sections of myenteric ganglia.TNFRs levels were measured by enzyme-linked immunosorbent assay in muscle/myenteric plexus-containing(MUSCLE-MP)tissue homogenates from different gut segments and experimental conditions.RESULTS A distinct region-dependent TNFRs expression was detected in controls.The density of TNFR1-labeling gold particles was lowest,while TNFR2 density was highest in duodenal ganglia and a decreased TNFRs expression from proximal to distal segments was observed in MUSCLE-MP homogenates.In diabetics,the TNFR2 density was only significantly altered in the duodenum with decrease in the ganglia(0.32±0.02 vs 0.45±0.04,P<0.05),while no significant changes in TNFR1 density was observed.In diabetic MUSCLE-MP homogenates,both TNFRs levels significantly decreased in the duodenum(TNFR1:4.06±0.65 vs 20.32±3.1,P<0.001;TNFR2:11.72±0.39 vs 15.91±1.04,P<0.01),which markedly influenced the TNFR2/TNFR1 proportion in both the ganglia and their muscular environment.Insulin treatment had controversial effects on TNFR expression.CONCLUSION Our findings show diabetes-related region-dependent changes in TNFR expression and suggest that TNFR2 is more affected than TNFR1 in myenteric ganglia in the duodenum of type 1 diabetic rats.