Attenuating CV risk factors in patients with diabetes: clinical evidence to clinical practice

Anti-Hyperglycemic Effect of the Brown Slime Cap Mushroom Chroogomphus rutilus (Agaricomycetes) Crude Polysaccharide In Vitro and In Vivo

The prevalence of diabetes is increasing worldwide, and it is very important to study new hypoglycemic active substances. In this study, we investigated the hypoglycemic effect of Chroogomphus rutilus crude polysaccharide (CRCP) in HepG2 cells and streptozotocin-induced diabetic mice. A glucose consumption experiment conducted in HepG2 cells demonstrated the in vitro hypoglycemic activity of CRCP. Furthermore, CRCP exhibited significant hypoglycemic effects and effectively ameliorated insulin resistance in insulin resistant HepG2 cells. In high-fat diet and streptozotocin-induced diabetic mice, after 4 weeks of CRCP administration, fasting blood glucose, fasting serum insulin, triglyceride, total cholesterol, low-density lipoprotein cholesterol, glutamate transaminase, alanine transaminase, and insulin resistance index significantly decreased, while high-density lipoprotein cholesterol and insulin sensitivity index (ISI) were markedly increased. Moreover, hematoxylin-eosin (HE) staining and immunofluorescence labeling of tissue sections indicated that CRCP attenuated the pathological damage of liver and pancreas in diabetic mice. These results indicate that CRCP is a potential hypoglycemic agent.

Optimization of ultrasonic-assisted extraction of polyphenols from the polyherbal formulation of Cinnamomum verum, Origanum majorana, and Origanum vulgare and their anti-diabetic capacity in zebrafish (Danio rerio)

The Cinnamomum verum (CV), Origanum majorana (CM), and Origanum vulgare (OV) have been used in traditional medicine in several regions of México for their anti-diabetic properties. In this study investigated the variables of ultrasound-assisted extraction for the polyphenolic compounds from the combination of these plants and explore their potential antidiabetic activities on glucose-induced-diabetic zebrafish. Determined the optimum conditions for ultrasonic-assisted extraction (UAE) to maximum recovery amounts of phenolic compounds from the extract of these plants. Polyphenols were detected in the extracts using HPLC-DAD-analysis. Extracts were evaluated on zebrafish exposed to high glucose concentration (110 mM) for two weeks. Results showed second-order polynomial mathematical models with a high coefficient of determination (R2 > 0.9564). Optimized extraction conditions for UAE from the combination of the 3 plants (COV) were as follows: 66.03%, ethanol, 28.87 min, and 21.51 mL/g for maximal flavonoids extraction. Used the same optimal extraction conditions for CV, CM, and OV. Results from LC-MS/MS indicated 9 polyphenolic compounds in CV, 12 in CM, and 6 in OV, the content of total polyphenols was 310.28, 90.42, and 126.74 mg GAE 100 g-1 dry weight, respectively. However, hyperglycemic fish showed an increase in cholesterol and triglyceride levels whereas extracts completely prevented these metabolic alterations. COV showed higher anti-diabetic ability than CV, CM, and OV, suggesting a synergistic effect between them. Our investigation developed a new herbal formulation of Cinnamomum verum; Origanum majorana; Origanum vulgare that has proven effective in animals with type 2 diabetes will form a new class of supplements to treat diabetic complications.

Hydroalcoholic Extract of Solanum lycocarpum A. St. Hil. (Solanaceae) Leaves Improves Alloxan-Induced Diabetes Complications in Mice

BACKGROUND

Solanum lycocarpum is a medicinal plant widely-used in Brazil because its fruits have hypoglycemic activity. However, the fruits are restricted in some periods of the year.

OBJECTIVE

To evaluate the effects of hydroalcoholic extracts of S. lycocarpum leaves in alloxan-induced diabetic mice.

METHODS

Hydroalcoholic extract of S. lycocarpum was characterized by phytochemical and GC-MS analysis. The Antidiabetic activity was assessed following treatment for 22 days with S. lycocarpum extract at 125, 250, and 500 mg/kg. Bodyweight, water, and food intake, glycemia, biochemical parameters, anatomy-histopathology of the pancreas, liver and kidney, and expression of target genes were analyzed. In addition, oral acute toxicity was evaluated.

RESULTS

Animals treated showed a significant reduction (p < 0.05) in glycemia following a dose of 125 mg/kg. Food intake remained similar for all groups. Decreased polydipsia symptoms were observed after treatment with 250 (p < 0.001) and 500 mg/kg (p < 0.01) compared with diabetic control, although normal rates were observed when 125 mg/kg was administered. A protective effect was also observed in the pancreas, liver, and kidneys, through the regeneration of the islets. Hypoglycemic activity can be attributed to myo-inositol, which stimulates insulin secretion, associated with α-tocopherol, which prevents damage from oxidative stress and apoptosis of β-pancreatic cells by an increased Catalase (CAT) and Glutathione peroxidase 4 (GPX4) mRNA expression. The toxicological test demonstrated safe oral use of the extract under the present conditions.

CONCLUSION

Hydroalcoholic extract of S. lycocarpum promotes the regulation of diabetes in the case of moderate glycemic levels, by decreasing glycemia and exerting protective effects on the islets.

Hypoglycemic, antidyslipidemic and antioxydant effects of Vitellaria paradoxa barks extract on high-fat diet and streptozotocin-induced type 2 diabetes rats

Backgroud

Vitellaria paradoxa is a plant belonging to the Sapotaceae family and used in traditional medicine in the treatment of diabetes mellitus. The aim of this work was to evaluate the hypoglycemic, antidyslipidemic and antioxidant effects of V. paradoxa on type 2 diabetic rats.

Methods

To induce type 2 diabetes mellitus (T2DM), animals were fed a high-fat diet for 4 weeks followed by an intraperitoneal injection of 35 mg/kg of streptozotocin. Diabetic rats were divided into groups and treated for 28 days with V. paradoxa extract (AEVP) at doses of 125, 250 and 500 mg/kg. Body weight, urine volume, food and water consumption were assessed at the start and end of treatment. The glucose tolerance test was performed on the last day of treatment. Blood samples were taken for the assay of biochemical parameters, organs (kidneys and liver) for markers of oxidative stress and pancreas for histological sections.

Results

AEVP (250 and 500 mg/kg) improved the drop in body weight, polyphagia, polydipsia and polyuria in diabetic rats. AEVP significantly reduced the concentrations of glucose, total cholesterol, triacylglycerol, urea, creatinine, activities of transaminases, and increased the levels of high density lipoprotein cholesterol and serum insulin. AEVP resulted in a decrease in malondialdehyde levels and an increase in catalase and superoxide dismutase activities. An increase in the size and number of islets in the pancreas has also been observed after administration of the extract.

Conclusion

AEVP has antidiabetic, antidyslipidemic and antioxidant properties, thus confirming its traditional use for the treatment of diabetes. These effects could be due to the presence of phytoconstituents, phenols and flavonoids presents in the plant extract.

Hesperidin improves hepatic steatosis, hepatic enzymes, and metabolic and inflammatory parameters in patients with nonalcoholic fatty liver disease: A randomized, placebo-controlled, double-blind clinical trial

This study aimed to evaluate the effects of hesperidin on nonalcoholic fatty liver disease (NAFLD) characteristics. In this randomized, double-blind, controlled clinical trial, 50 NAFLD patients were supplemented with either 1-g hesperidin capsule or identical placebo capsule for 12 weeks. During the intervention, both groups were advised to follow healthy lifestyle habits including dietary and physical activity recommendations. At the end of the study, hesperidin supplementation, compared with placebo, was associated with a significant reduction in alanine aminotransferase (p = .005), γ-glutamyltransferase (p = .004), total cholesterol (p = .016), triglyceride (p = .049), hepatic steatosis (p = .041), high-sensitivity C-reactive protein (p = .029), tumor necrosis factor-α, and nuclear factor-κB (NF-κB). In conclusion, our results indicate that hesperidin supplementation accompanied with lifestyle modification is superior to lifestyle modification alone in management of NAFLD at least partially through inhibiting NF-κB activation and improving lipid profile. Further studies with higher dose of hesperidin are required to find the optimal dose.

Antidiabetic Effect of Monolluma quadrangula Is Mediated via Modulation of Glucose Metabolizing Enzymes, Antioxidant Defenses, and Adiponectin in Type 2 Diabetic Rats

Monolluma quadrangula is a succulent bush traditionally used to treat diabetes and peptic ulcer. The present study aimed to investigate the effect of M. quadrangula hydroethanolic extract on glucose tolerance, insulin sensitivity, glucose metabolizing enzymes, lipid profile, and adiponectin expression in type 2 diabetic rats. In addition, the study evaluated the antioxidant and anti-inflammatory activities of the M. quadrangula extract. Type 2 diabetes was induced by feeding rats a high-fat diet (HFD) for 8 weeks followed by 30 mg/kg streptozotocin (STZ). Diabetic rats received 300 or 600 mg/kg M. quadrangula extract for 4 weeks. HFD/STZ diabetic rats showed impaired glucose tolerance, reduced insulin secretion, and insulin resistance. HFD and STZ induced a significant increase in serum cholesterol, triglycerides and proinflammatory cytokines, and liver lipid peroxidation. Treatment with M. quadrangula extract ameliorated these metabolic disturbances and increased liver glycogen, hexokinase activity, and antioxidants. M. quadrangula declined the activity of liver glucose-6-phosphatase and fructose-1,6-biphosphatase. In addition, M. quadrangula extract increased serum adiponectin levels and hepatic adiponectin expression in HFD/STZ diabetic rats. In conclusion, M. quadrangula exerts antidiabetic effect mediated via ameliorating glucose tolerance, insulin sensitivity, glucose metabolizing enzymes, and antioxidant defenses. Increased adiponectin levels and expression seems to mediate, at least in part, the antidiabetic effect of M. quadrangula.

The reverse metabolic syndrome in the elderly: Is it a "catabolic" syndrome?

Traditional risk factors of cardiovascular death in the general population, including body mass index (BMI), serum cholesterol, and blood pressure are also found to relate to outcomes in the geriatric population, but in a differing direction. A higher body mass index, hypercholesterolemia and hypertension are not harmful but even permit better survival at advancing age. This phenomenon is called "reverse epidemiology" or "risk factor paradox" and is also detected in a variety of chronic disease states such as chronic heart failure. Accordingly, a low BMI, blood pressure and cholesterol values are associated with a worse prognosis. Several possible causes are hypothesized to explain this elderly paradox, but this phenomenon remains controversial and its underlying reasons are poorly understood. The aim of this review is to recognize the factors behind this intriguing phenomenon and analyse the consequences that it can bring in the management of the cardiovascular therapy in elderly patient. Finally, a new phenotype identified as "catabolic syndrome" has been postulated.

Navel orange peel hydroethanolic extract, naringin and naringenin have anti-diabetic potentials in type 2 diabetic rats

The therapy of Type 2 Diabetes Mellitus (T2DM) stays a challenging issue. During the last decade, there has been an interest in the expansion of anti-diabetic drugs especially those of natural sources. Thus, the aim of this study was to assess the anti-hyperglycemic and the anti-hyperlipidemic effects as well as the anti-oxidant activities of navel orange hydroethanolic extract and its constituting flavonoids naringin and naringenin on nicotineamide (NA)/streptozotocin (STZ)-induced type 2 diabetic rats. To induce T2DM, 16h-fasted rats were intraperitoneally injected with STZ at dose of 50mg/kg body weight (b. w.), 15min after the intraperitoneal administration of NA (120mg/kg b. w.). The NA/STZ-induced type 2 diabetic rats were orally treated with navel orange peel hydroethanolic extract, naringin and narengenin at dose level of 100mg/kg b. w./day for 4 weeks. The treatments with navel orange peel hydroethanolic extract, naringin and narengenin potentially alleviated the lowered serum insulin and C-peptide levels, the depleted liver glycogen content, the elevated liver glucose-6-phosphatase and glycogen phosphorylase activities, the deteriorated serum lipid profile, and the suppressed liver antioxidant defense system of NA/STZ-induced type 2 diabetic rats. The treatments also enhanced the mRNA expression of insulin receptor β-subunit, GLUT4 and adiponectin in adipose tissue of STZ/NA-induced type 2 diabetic rats. In conclusion, the navel orange peel hydroethanolic extract, naringin and naringenin have potent anti-diabetic effects in NA/STZ-induced type 2 diabetic rats via their insulinotropic effects and insulin improving action which in turn may be mediated through enhancing insulin receptor, GLUT4 and adiponectin expression in adipose tissue.

Antihyperglycemic, antihyperlipidemic and antioxidant effects of standard ethanol extract of Bombax ceiba leaves in high-fat-diet- and streptozotocin-induced Type 2 diabetic rats

The present study aimed at exploring the therapeutic potential of standard extract of Bombax ceiba L. leaves (BCE) in type 2 diabetic mellitus (T2DM). Oral administration of BCE at doses of 70, 140, and 280 mg·kg^-1, to the normal rats and the high-fat-diet- and streptozotocin-induced T2DM rats were carried out. Effects of BCE on blood glucose, body weight, and a range of serum biochemical parameters were tested, and histopathological observation of pancreatic tissues was also performed. HPLC-ESI-Q/TOF-MS/MS analysis indicated that the chemical composition of BCE mainly contained mangiferin, isoorientin, vitexin, isomangiferin, isovitexin, quercetin hexoside, 2'-trans-O-cumaroyl mangiferin, and nigricanside. BCE caused a significant decrease in the concentrations of fasting blood glucose, glycosylated hemoglobin, total cholesterol, triglyceride, low density lipoprotein-cholesterol, serum insulin, and malondialdehyde, and increases in oral glucose tolerance, high density lipoprotein-cholesterol, and superoxide dismutase in the T2DM model rats. Moreover, considerable pancreatic β-cells protection effect and stimulation of insulin secretion from the remaining pancreatic β-cells could be observed after BCE treatment. The results indicated that BCE exhibited an excellent hypoglycemic activity, and alleviated dyslipidemia which is associated with T2DM. Antioxidant activity and protecting pancreatic β-cells are the possible mechanisms involved in anti-diabetic activity of BCE.

Antidiabetic and antidyslipidemic activities of aqueous leaf extract of Dioscoreophyllum cumminsii (Stapf) Diels in alloxan-induced diabetic rats

ETHNOPHARMACOLOGICAL RELEVANCE

Dioscoreophyllum cumminsii (Stapf) Diels leaves are used in the management of diabetics in Nigeria. Thus, the antidiabetic activity of aqueous D. cumminsii leaf extract and its capability to halt oxidative stress and dyslipidemia in alloxan-induced diabetic rats was investigated.

METHODOLOGY

Antidiabetic was evaluated in alloxan-induced diabetes rats. Diabetic rats were treated with 50, 100 and 200mg/kg body weight of the extract.

RESULT

The aqueous extract of D. cumminsii leaves significantly reduced blood glucose level in a dose dependent manner with highest dose producing 72% reduction after 21 days administration, which was compared significantly (P<0.05) with the control group and glibenclamide treated groups. Similarly, aqueous extract of D. cumminsii significantly reversed reduction in insulin in alloxan-induced diabetic rats. Alloxan-induced diabetic mediated alterations in liver and serum cholesterol, triacylglycerides, high-density lipoprotein cholesterol (HDLc), low density lipoprotein cholesterol (LDLc) and very low-density lipoprotein cholesterol (VLDLc) were significantly (P<0.05) restored by the extract. Aqueous extract of D. cumminsii leaves significantly attenuated the decrease in the activities of superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase and glucose 6-phosphate dehydrogenase in the liver and pancreas of alloxan-induced diabetic rats. Elevation in the concentration of malondialdehyde was significantly (P<0.05) lowered by D. cumminsii leaves extract. The diabetic-mediated alteration in the architecture of liver was alleviated by the extract.

CONCLUSION

Overall, aqueous extract of D. cumminsii leaves at all doses investigated reduced blood glucose level and prevented oxidative stress and dyslipidemia in alloxan-induced diabetic rats.

Association between whole blood viscosity and arterial stiffness in patients with type 2 diabetes mellitus

Type 2 diabetes mellitus (DM) carries an increased risk for cardiovascular complications. The brachial-ankle pulse wave velocity (baPWV) is an index for early atherosclerotic changes. Recently, the effect of altered blood rheology on atherosclerosis has received attention. Therefore, this study aimed to examine the association of hemorheological parameters with baPWV in patients with DM. In this cross-sectional study, we investigated the relationship between rheological parameters and baPWV in 323 control subjects (160 men and 163 women) and 382 patients with DM (170 men and 212 women). The participants with DM had higher whole blood viscosity (WBV) levels both at low shear rate (3 s(-1)) and at high shear rate (200 s(-1)) than those without DM. Different metabolic parameters were compared across WBV (3 s(-1)) quartiles. The mean values of baPWV gradually increased with WBV (3 s(-1)) quartiles. In addition, there was a positive correlation between baPWV and WBV 3 s(-1) in patients with DM after adjusting confounding factors (r = 0.285, p = 0.039). Stepwise multiple linear regression analysis further revealed that WBV (3 s(-1)) is a significant determinant for increased baPWV in DM (β = 0.184; p < 0.001). However, there were no association between WBV (3 s(-1)) and baPWV in control subjects. The findings showed that baPWV increased as WBV (3 s(-1)) elevated in DM. Moreover, WBV (3 s(-1)) is independently associated with baPWV even after adjusting other cardiovascular risk factors. Early detection of abnormal WBV levels at low shear rate should warrant for early search of undetected arterial stiffness in patients with DM.

Paraoxonase-1 gene Q192R and L55M polymorphisms and risk of cardiovascular disease in Egyptian patients with type 2 diabetes mellitus

Background

Increased oxidative stress or an impaired antioxidant defense mechanism may play a crucial role in the onset and progression of atherosclerosis. Recently, Paraoxonase −1 (PON1) which accounts for most of the antioxidant effect of high density lipoprotein (HDL) cholesterol has been presented as a potential therapeutic agent against atherosclerosis development. Allele frequencies for PON1 gene that influence enzyme concentration as well as activity differ greatly among ethnic groups and data from several studies showed ethnic variations in the interpretation of cardiovascular disease (CVD) associated with PON1 polymorphisms. In this work, we investigated PON1 Q192R and L55M polymorphisms in Egyptian patients with type 2 diabetes mellitus (T2DM) and its association with CVD.

Methods

The study included 184 subjects classified into 3 groups; T2DM, T2DM + CVD, and healthy controls. PON1 polymorphisms were genotyped by real-time PCR and PON1 concentration was assayed in serum by ELISA (enzyme linked immunesorbent assay).

Results

Genotype and allele frequencies of Q192R were significantly different between controls and diabetic patients. Frequency of QQ genotype was significantly higher in healthy controls, while QR and RR genotypes were significantly higher in diabetic patients (p = 0.02). Frequency of 55LL and LM genotypes were significantly higher in patients than in controls (p = 0.009). Q192R polymorphism associated with CVD in our diabetic patients (p = 0.01) and with low serum PON1 concentration (p = 0.04). Multiple logistic regression analysis revealed significant correlations between 192R and other independent CVD risk factors.

Conclusion

PON1 192R and 55 L alleles are associated with T2DM. Q192R polymorphism is associated with CVD and lower serum enzyme concentration and might represents a novel risk factor for CVD in Egyptian patients with T2DM.

Blighia sapida leaves halt elevated blood glucose, dyslipidemia and oxidative stress in alloxan-induced diabetic rats

ETHNOPHARMACOLOGICAL RELEVANCE

Blighia sapida leaves are used in the management of diabetes in Nigeria. Thus the antidiabetic activity of methanolic Blighia sapida leaf extract and its capability to halt oxidative stress and dyslipidemia in alloxan-induced diabetic rats were investigated.

METHODS

In vitro antioxidant activity of the extract (0.2-1.0mg/mL) was investigated using 2,2-diphenyl-1-1picrylhydrazyl (DPPH) radical, superoxide ion, hydrogen peroxide, and hydroxyl radical and ferric ion reducing system. Antidiabetic was evaluated in alloxan-induced diabetic rats.

RESULTS

The methanolic extract of Blighia sapida leaves at 1.0mg/mL scavenged DPPH, superoxide ion, hydrogen peroxide, and hydroxyl radical at 80.34%, 57.39%, 72.36% and 77.0% respectively, while ferric ion was significantly reduced. Single oral dose of the extract significantly reduced blood glucose level in a dose dependent manner with highest dose producing 18.6% reduction after 240min. Similar reduction was produced after 28 days of extract administration with the highest dose producing 65.65% reduction which compared significantly (P<0.05) with the control group and glibenclamide treated groups. Alloxan-induced diabetic mediated alterations in liver and serum cholesterol, triacylglycerides, high-density lipoprotein cholesterol (HDLc), low density lipoprotein (LDL) cholesterol and very low-density lipoprotein cholesterol (VLDLc) were significantly (P<0.05) restored by the extract. Methanolic extract of Blighia sapida leaves significantly attenuated the decrease in the activities of reactive oxygen species detoxifying enzymes (superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase and glucose 6-phosphate dehydrogenase) in the liver and pancreas of alloxan-induced diabetic rats. Elevation in the concentrations of malondialdehyde, conjugated dienes, lipid hydroperoxides, protein carbonyl, and fragmented DNA was significantly (P<0.05) lowered by Blighia sapida leaves extract.

CONCLUSION

Overall, methanolic extract of Blighia sapida leaves at all doses used reduced blood glucose level and prevented oxidative stress and dyslipidemia in alloxan-induced diabetic rats.

Association between whole blood viscosity and arterial stiffness in patients with type 2 diabetes mellitus

Type 2 diabetes mellitus (DM) carries an increased risk for cardiovascular complications. The brachial-ankle pulse wave velocity (baPWV) is an index for early atherosclerotic changes. Recently, the effect of altered blood rheology on atherosclerosis has received attention. Therefore, this study aimed to examine the association of hemorheological parameters with baPWV in patients with DM. In this cross-sectional study, we investigated the relationship between rheological parameters and baPWV in 323 control subjects (160 men and 163 women) and 382 patients with DM (170 men and 212 women). The participants with DM had higher whole blood viscosity (WBV) levels both at low shear rate (3 s(-1)) and at high shear rate (200 s(-1)) than those without DM. Different metabolic parameters were compared across WBV (3 s(-1)) quartiles. The mean values of baPWV gradually increased with WBV (3 s(-1)) quartiles. In addition, there was a positive correlation between baPWV and WBV 3 s(-1) in patients with DM after adjusting confounding factors (r = 0.285, p = 0.039). Stepwise multiple linear regression analysis further revealed that WBV (3 s(-1)) is a significant determinant for increased baPWV in DM (β = 0.184; p < 0.001). However, there were no association between WBV (3 s(-1)) and baPWV in control subjects. The findings showed that baPWV increased as WBV (3 s(-1)) elevated in DM. Moreover, WBV (3 s(-1)) is independently associated with baPWV even after adjusting other cardiovascular risk factors. Early detection of abnormal WBV levels at low shear rate should warrant for early search of undetected arterial stiffness in patients with DM.

Anti-hyperglycemic and Anti-hyperlipidemic Effects of Bryonia Laciniosa Seed Extract and its Saponin Fraction in Streptozotocin-induced Diabetes in Rats

Bryonia laciniosa Linn. (Cucurbitaceae) seed is used in traditional medicine for a number of ailments including metabolic disorders. This investigation was carried out to investigate the anti-hyperglycemic and anti-hyperlipidemic potential of the ethanolic extract of seeds of B. laciniosa Linn. and its saponin fraction in streptozotocin-induced diabetic rats. The ethanolic extract (250 and 500 mg/kg; p.o.) and saponin fraction (100 and 200 mg/kg; p.o.) were administered to diabetic rats and standard drug insulin (5 IU/kg; i.p.) to the group serving as a positive control. Effects of the ethanolic extract and saponin fraction on various biochemical parameters were studied in diabetic rats. Data were statistically analysed by one-way ANOVA followed by Dunnett's t-test. Oral administration of the ethanolic extract and saponin fraction for 28 days to streptozotocin-induced diabetes rats significantly (P < 0.05) decreased the levels of blood glucose and improved the levels of plasma insulin. The levels of triglycerides, cholesterol, high density lipoprotein, low density lipoprotein, very low density lipoprotein, aspartate amino transferase and alanine amino transferase, urea, and creatinine were markedly altered in streptozotocin-induced diabetic rats. Oral administration of the ethanolic extract and saponin fraction restored all these biochemical parameters to near control levels. This study reveals the efficacy of B. laciniosa seed extract and its saponin fraction in the amelioration of diabetes and its associated complications.

Insulinotrophic and hypolipidemic effects of Ecklonia cava in streptozotocin-induced diabetic mice

OBJECTIVE

To explore the anti-diabetic activity of Ecklonia cava (EC) in streptozotocin (STZ)-induced diabetic mice.

METHODS

Diabetes was induced by a single intraperitoneal injection of STZ (90 mg/kg). Normal and diabetic mice were treated with 0%, 3%, and 5% EC diet for 4 weeks. Serum glucose and insulin concentrations, serum lipid profile, oral glucose tolerance test, and liver and pancreatic β-cell histopathological observations were performed. In addition, in vitro glucose-induced insulin secretion was determined using pancreatic β-islet cells.

RESULTS

EC supplementation significantly and dose-dependently decreased serum glucose concentration, and improved glucose homeostasis in diabetic mice by preventing loss of β-cell mass resulting in increase of insulin secretion. The triglyceride and total cholesterol concentrations in the serum and liver were markedly reduced by EC treatment in STZ-diabetic mice. Moreover, LDL-, and HDL-cholesterol levels were ameliorated in EC supplemented diabetic mice. Liver steatosis induced by STZ was ameliorated by EC supplementation. Furthermore, in vitro insulinotrophic effect of EC extract was observed in pancreatic β-islets.

CONCLUSIONS

This study demonstrated that EC is a potent and efficacious hypoglycemic and hypolipidemic agent, and prevents the loss of β-cell mass resulting in increase of insulin secretary capacity.

Effect of a novel proteoglycan PTP1B inhibitor from Ganoderma lucidum on the amelioration of hyperglycaemia and dyslipidaemia in db/db mice

Protein tyrosine phosphatase 1B (PTP1B) is implicated in the negative regulation of the insulin signalling pathway by dephosphorylating the insulin receptor (IR) and IR substrates. Ganoderma lucidum has traditionally been used for the treatment of diabetes in Chinese medicine; however, its anti-diabetic potency and mechanism in vivo is still unclear. Our previously published study reported a novel proteoglycan PTP1B inhibitor, named Fudan-Yueyang-Ganoderma lucidum (FYGL) from G. lucidum, with a half-maximal inhibitory concentration (IC₅₀) value of 5·12 (sem 0·05) μg/ml, a protein:polyglycan ratio of 17:77 and 78 % glucose in polysaccharide, and dominant amino acid residues of aspartic acid, glycine, glutamic acid, alanine, serine and threonine in protein. FYGL is capable of decreasing plasma glucose in streptozotocin-induced diabetic mice with a high safety of median lethal dose (LD₅₀) of 6 g/kg. In the present study, C57BL/6 db/db diabetic mice were trialed further using FYGL as well as metformin for comparison. Oral treatment with FYGL in db/db diabetic mice for 4 weeks significantly (P < 0·01 or 0·05) decreased the fasting plasma glucose level, serum insulin concentration and the homeostasis model assessment of insulin resistance. FYGL also controlled the biochemistry indices relative to type 2 diabetes-accompanied lipidaemic disorders. Pharmacology research suggests that FYGL decreases the plasma glucose level by the mechanism of inhibiting PTP1B expression and activity, consequently, regulating the tyrosine phosphorylation level of the IR β-subunit and the level of hepatic glycogen, thus resulting in the improvement of insulin sensitivity. Therefore, FYGL is promising as an insulin sensitiser for the therapy of type 2 diabetes and accompanied dyslipidaemia.

Salutary effect of Cassia auriculata L. Leaves on hyperglycemia-induced atherosclerotic environment in streptozotocin rats

Diabetes mellitus is very often associated with dyslipidemia, increased oxidative stress and endothelial dysfunction that could develop atherosclerosis and consequently cardiovascular diseases. Medicinal plants with reputed traditional use to treat diabetes and cardiovascular diseases might provide valuable drugs. Therefore, the present study was designed to evaluate anti-atherosclerotic potential of aqueous extract of Cassia auriculata L. leaves in streptozotocin (STZ)-induced diabetic rats. The rats were rendered diabetic by STZ (45 mg/kg, ip). Diabetic rats were orally administered C. auriculata leaf extract at 400 mg/kg dose daily for 21 days. The supplementation of extract to the diabetic rats produced significant reduction in fasting blood glucose along with significant reversal in altered serum lipid profile and apolipoprotein B. Lipid peroxidation was found to be significantly suppressed in extract-fed diabetic rats. The significant reduction in serum levels of oxidized low-density lipoprotein, soluble vascular cell adhesion molecule and plasma fibrinogen with a concomitant elevation in serum nitric oxide was observed in diabetic rats following treatment with extract. Histopathological examination of heart myocardium of extract-treated diabetic rats revealed reversal of fatty change toward normal. These results suggest that C. auriculata aqueous leaf extract exhibits anti-atherosclerotic role in the diabetic state and it indicates toward the notion that extract may help to prevent the progression of cardiovascular diseases.

Ileal apical Na+-dependent bile acid transporter ASBT is upregulated in rats with diabetes mellitus induced by low doses of streptozotocin

Increased intestinal bile acid absorption and expansion of the bile acid pool has been implicated in the hypercholesterolemia associated with diabetes mellitus. However, the molecular basis of the increase in bile acid absorption in diabetes mellitus is not fully understood. The ileal apical Na(+)-dependent bile acid transporter (ASBT) is primarily responsible for active reabsorption of the majority of bile acids. Current studies were designed to investigate the modulation of ASBT function and expression in streptozotocin (STZ)-induced diabetes mellitus in rats and to examine the effect of insulin on rat ASBT promoter by insulin. Diabetes mellitus was induced in Sprague-Dawley rats by intraperitoneal injection of low doses of STZ (20 mg/kg body wt) on five consecutive days. Human insulin (10 U/day) was given to a group of diabetic rats for 3 days before euthanasia. RNA and protein were extracted from mucosa isolated from the small intestine and ASBT expression was assessed by real-time quantitative RT-PCR and Western blotting. Our data showed that ASBT mRNA and protein expression were significantly elevated in diabetic rats. Insulin treatment of diabetic rats reversed the increase in ASBT protein expression to control levels. Consistently, ileal Na(+)-dependent [(3)H]taurocholic uptake in isolated intestinal epithelial cells was significantly increased in diabetic rats. In vitro studies utilizing intestinal epithelial Caco-2 cells demonstrated that ASBT expression and promoter activity were significantly decreased by insulin. These studies demonstrated that insulin directly influences ASBT expression and promoter activity and that ASBT function and expression are increased in rats with STZ-induced diabetes mellitus. The increase in ASBT expression may contribute to disturbances in cholesterol homeostasis associated with diabetes mellitus.

Combination therapy with mitiglinide and voglibose improves glycemic control in type 2 diabetic patients on hemodialysis

OBJECTIVE

Mitiglinide, a rapid- and short-acting insulinotropic sulfonylurea receptor ligand, exhibits hypoglycemic action unlike other sulfonylureas. The efficacy of the combination of mitiglinide and alpha-glucosidase inhibitors for diabetic patients on hemodialysis (HD) has not been prospectively evaluated; therefore, we evaluated the efficacy and safety of mitiglinide in these patients.

RESEARCH DESIGN AND METHODS

We performed an open-label randomized study with 36 type 2 diabetics with poor glycemic control on HD and receiving daily doses of voglibose (0.9 mg). The patients were randomly assigned to two groups: a combination-therapy group (mitiglinide group), mitiglinide initial dose 7.5 - 15 mg titrated to 30 mg daily and constant daily dose 0.9 mg of voglibose, and a monotherapy group (control group), constant daily dose 0.9 mg of voglibose alone. The efficacy of the treatment was determined by monitoring plasma glucose, hemoglobin A1c (Hb(A1c)), and glycated albumin (GA) levels and using homeostasis model assessment of insulin resistance (HOMA-IR). Safety and tolerance were determined by monitoring clinical and laboratory parameters.

RESULTS

The final dose of mitiglinide was 22.9 +/- 8.9 (mean +/- s.d.) mg (0.41 mg/kg) daily. Mitiglinide reduced fasting plasma glucose and GA levels after 4 weeks and Hb(A1c) levels after 8 weeks. Triglyceride levels and HOMA-IR values also decreased significantly after mitiglinide treatment. No significant changes in blood pressure levels or serious adverse effects such as hypoglycemia or liver impairment were observed.

CONCLUSIONS

This study suggests a combination therapy of mitiglinide and voglibose may have potential for the treatment of diabetics on HD. Due to the small sample size used, further studies should be performed, particularly to assess the safety of mitiglinide treatment.

Protective effect of rutin on lipids, lipoproteins, lipid metabolizing enzymes and glycoproteins in streptozotocin-induced diabetic rats

The protective role of rutin on lipids, lipoproteins, lipid metabolizing enzymes and glycoproteins in streptozotocin-induced diabetic rats has been studied. A single intraperitoneal injection of streptozotocin (50 mg kg−1) to rats led to a significant (P &lt; 0.05) increase in the levels of lipids (cholesterol, triglycerides, free fatty acids and phospholipids) in plasma and tissues (liver, kidney, heart and brain). The levels of low density and very low density lipoprotein (LDL and VLDL, respectively) cholesterol were increased, whereas the levels of high density lipoprotein (HDL) cholesterol were decreased significantly (P &lt; 0.05) in plasma. The activity of 3-hydroxy 3-methylglutaryl coenzyme A (HMG CoA) reductase increased significantly (P &lt; 0.05) in liver, kidney and heart, and the activity of lipoprotein lipase (LPL) and lecithin cholesterol acyltransferase (LCAT) decreased significantly (P &lt; 0.05) in the plasma of diabetic rats. Streptozotocin injection also increased the levels of glycoproteins such as hexose, hexosamine, fucose and sialic acid in plasma, liver and kidney. Oral administration of rutin to streptozotocin-induced diabetic rats significantly (P &lt; 0.05) decreased the levels of lipids in plasma and tissues. The levels of plasma HDL-cholesterol increased and the levels of LDL- and VLDL-cholesterol decreased significantly (P &lt; 0.05). The activity of HMG CoA reductase decreased in the tissues and the activity of plasma LPL and LCAT increased significantly (P &lt; 0.05). The levels of glycoproteins were found to be significantly (P &lt; 0.05) decreased in plasma, liver and kidney of rutin-treated diabetic rats. Rutin administration to normal rats did not exhibit any significant (P &lt; 0.05) changes in any of the parameters studied. In conclusion, the beneficial effect of rutin on lipids, lipoproteins, lipid metabolizing enzymes and glycoproteins could be due to its antioxidant property.

Antihyperglycemic and hypolipidemic activity of aqueous extract of Cassia auriculata L. leaves in experimental diabetes

ETHNOPHARMACOLOGICAL RELEVANCE

Cassia auriculata L. (Caesalpiniaceae) is widely used from ancient period to treat diabetes mellitus. The leaves of Cassia auriculata are having potential in the development of drug for diabetes due to its antihyperglycemic and lipid-lowering activity.

AIM OF THE STUDY

The present study was to evaluate antihyperglycemic and hypolipidemic activity of aqueous extract of Cassia auriculata leaves (CLEt) in streptozotocin (STZ)-induced mild diabetic (MD) and severe diabetic (SD) rats.

MATERIALS AND METHODS

Male Albino rats were rendered diabetic by STZ (45 mg/kg, intraperitoneally). CLEt was orally administered to MD and SD rats at 100, 200 and 400 mg/kg doses for 1 day to determine antihyperglycemic activity. The 400 mg/kg dose was administered daily for 3 weeks to assess glycemic control and hypolipidemic effect.

RESULTS

CLEt showed dose dependant fall in fasting blood glucose (FBG). After 5h of extract administration at 400mg/kg dose, FBG was reduced by 13.9% and 17.4% in MD and SD rats respectively. After 3 weeks treatment, CLEt produced significant reduction in FBG and glycosylated haemoglobin (GHb) in both MD and SD rats. Serum lipid levels were reversed towards normal in extract fed MD and SD rats.

CONCLUSIONS

The results demonstrate that CLEt possesses potent antihyperglycemic and hypolipidemic activity in both MD and SD rats.

Estimating the long-term cost-effectiveness of exenatide in the United States: an adjunctive treatment for type 2 diabetes mellitus

OBJECTIVES

This analysis provides an early estimate of the cost-effectiveness of adjunctive exenatide in treating type 2 diabetes mellitus in the United States. Data from pivotal phase III 30-week clinical trials and 52 weeks of their subsequent open-label extension studies (i.e., 82 weeks total) were used to project the effects of 30 years of adjunctive exenatide treatment.

METHODS

This analysis utilized a published and validated Markov model incorporating Monte Carlo simulation with tracker variables to estimate the clinical and cost outcomes of adding exenatide to a background of metformin and/or sulfonylurea treatment, with the effects of 30 years of adjunctive exenatide treatment (projected from data from 82 weeks of exenatide treatment) compared with no additional treatment beyond metformin and/or a sulfonylurea. Sensitivity analyses were performed on key clinical assumptions, discount rates, and shorter time horizons.

RESULTS

The base-case scenario (30 years of exenatide) yielded an incremental cost-effectiveness ratio (ICER) of $35,571. We found that shortening the time horizons and removing the lipid effects of exenatide had the greatest negative impact on ICERs when performing sensitivity analysis.

CONCLUSIONS

Our analysis demonstrated that exenatide used for 20 or 30 years compared with no additional treatment beyond metformin and/or a sulfonylurea is cost-effective in the adjunctive treatment of type 2 diabetes with an ICER less than $50,000 per life-year gained. Sensitivity analyses suggest that, in addition to sustained reduction in HbA(1c), the added clinical effects of improved lipid values, systolic blood pressure, and reduced body mass index all positively contributed to the cost-effectiveness of exenatide.

Evaluation of the hemodialysis-induced changes in plasma glucose and insulin concentrations in diabetic patients: comparison between the hemodialysis and non-hemodialysis days

Often, well-controlled plasma glucose levels but high hemoglobin A(1c) levels have been observed at prehemodialysis in diabetic patients. The present study aimed to evaluate this difference between fasting glucose and hemoglobin A(1c) levels. We investigated hemodialysis-induced alterations in the plasma glucose and insulin levels. Based on their glycemic control level at inclusion, subjects were divided into poor control (hemoglobin A(1c)> or =7.0%; n = 8) and good control groups (hemoglobin A(1c) <7.0%; n = 8). We measured their plasma glucose and immunoreactive insulin levels at arterial and venous sites at three time points (predialysis, 2 h and 4 h after starting dialysis); we also studied their daily plasma glucose profiles. In both the groups, the V-site plasma glucose and immunoreactive insulin levels were significantly decreased compared to the A-site levels at each time point. The A-site plasma immunoreactive insulin levels 4 h after dialysis were significantly decreased compared to the levels 2 h after dialysis. Comparison between hemodialysis and non-hemodialysis days revealed that the plasma glucose levels decreased significantly during hemodialysis and significantly increased between predinner and bedtime in the poor control group. The present study confirmed that hemodialysis decreased the plasma glucose and immunoreactive insulin levels. In the poor control group, hyperglycemia appeared posthemodialysis; this was attributed partly to the hemodialysis-induced decrease in the plasma immunoreactive insulin levels. These results suggest that although diet therapy has been effective in diabetic hemodialysis patients, hemodialysis caused hyperglycemia by absolute or relative plasma immunoreactive insulin deficiency.

[Incretins as new therapeutic targets of type 2 diabetes]

The epidemic characteristics of type 2 diabetes mellitus (DM) pose a formidable challenge in terms of healthcare, given the tremendous impact it has on the healthcare resources needed not only to treat it, but also to prevent and treat the associated cardiovascular complications. This makes up the number 1 cause of DM-associated morbidity-mortality in addition to its social and personal impact. We currently have a growing number of available treatment tools that make it possible to achieve the target glycemic control in most of our patients, albeit unfortunately, only temporarily in a good many of them, because of the progressive nature of the disease. Furthermore, current therapy often entails undesirable effects, such as weight gain or the emergence of hypoglycemias that limit their optimization. Recently, a new class of drugs has been incorporated into the treatment of DM - incretin mimetics. These new drugs act in very much the same way as the intestinal hormones that are naturally secreted following the intake of nutrients, called incretins (e.g., glucagon like peptide-1 [GLP-1]), with the added advantage that these molecules are resistant to enzymatic degradation by the DPP-IV enzyme. This provides them with a half-life that makes ambulatory treatment possible, unlike natural incretins whose half-life is too short to make them viable as treatment. The incretin mimetics bind to GLP-1 receptors, increasing glucose-dependent secretion of insulin and decreasing glucose-dependent posprandial secretion of glucagon, slowing gastric emptying, and reducing food intake. All these mechanisms have a significant impact on glucose homeostasis and a beneficial effect on body weight. Moreover, studies in experimental models suggest that these new molecules might have a promising effect on pancreatic beta cell function and mass. Exenatide is the first incretin mimetic available to date. Efficacy and safety data of this drug show it as a therapeutic option for the treatment of type 2 DM.

Interim analysis of the effects of exenatide treatment on A1C, weight and cardiovascular risk factors over 82 weeks in 314 overweight patients with type 2 diabetes

AIM

Exenatide, an incretin mimetic for the adjunct treatment of type 2 diabetes (DM2), reduced A1C and weight in 30-week placebo-controlled trials. This analysis examined the effects of exenatide on glycaemic control and weight over an 82-week period in patients with DM2 unable to achieve adequate glycaemic control with sulphonylurea (SU) and/or metformin (MET).

METHODS

This interim analysis is of 314 patients who received exenatide in the 30-week placebo-controlled trials and subsequently in 52 weeks of open-label uncontrolled extension studies for 82 weeks of exenatide in total. Patients continued their SU and/or MET regimens throughout.

RESULTS

Patients completed 82 weeks of exenatide treatment [n = 314, 63% M, age 56 +/- 10 years, weight 99 +/- 21 kg, body mass index 34 +/- 6 kg/m2, A1C 8.3 +/- 1.0% (mean +/- SD)]. Reduction in A1C from baseline to week 30 [-0.9 +/- 0.1% (mean +/- SE)] was sustained to week 82 (-1.1 +/- 0.1%), with 48% of patients achieving A1C < or = 7% at week 82. At week 30, exenatide reduced body weight (a secondary endpoint) from baseline (-2.1 +/- 0.2 kg), with progressive reduction at week 82 (-4.4 +/- 0.3 kg). Similar results were observed for the intent-to-treat population (n = 551), with reductions in A1C and weight at week 82 of -0.8 +/- 0.1% and -3.5 +/- 0.2 kg respectively. The 82-week completer cohort showed statistically significant improvement in some cardiovascular risk factors. The most frequent adverse events were generally mild-to-moderate nausea and hypoglycaemia.

CONCLUSION

In summary, 82 weeks of adjunctive exenatide treatment in patients with DM2 treated with SU and/or MET resulted in sustained reduction in A1C and progressive reduction in weight, as well as improvement in some cardiovascular risk factors.

Low incidence of vascular complications in patients with diabetes mellitus associated with liver cirrhosis as compared with type 2 diabetes mellitus

We compared clinical features and vascular complications of patients with diabetes mellitus associated with liver cirrhosis versus patients with type 2 diabetes mellitus. Subjects were 19 patients (LC-DM group) in whom diabetes was diagnosed after development of liver cirrhosis. Control consisted of 38 patients with type 2 diabetes (T2DM group) matched for sex, age, duration of diabetes, body mass index, treatment, and degree of glycemic control, which was determined by glycoalbumin. The LC-DM group had significantly more smokers, higher serum insulin levels, more insulin resistance calculated by homeostasis model assessment, lower blood counts (white and red blood cells, hemoglobin, and platelets), and lower serum levels of total cholesterol, triglyceride, low density lipoprotein cholesterol and lipoprotein (Lp)(a) than the T2DM group. The incidence of diabetic retinopathy and cerebrovascular disease was significantly lower in the LC-DM group compared to the T2DM group. Logistic regression analysis indicated that Lp(a) and the diabetes duration were significant predictors for the retinopathy, while Lp(a) was a significant predictor for the cerebrovascular complication. In diabetes associated with liver cirrhosis, the incidence of diabetic retinopathy and cerebrovascular disease is lower than in type 2 diabetes mellitus in this study, probably because of lower levels of serum Lp(a).