Plasma triglyceride transport kinetics in diabetes mellitus

Exposure to persistent organic pollutants alters the serum metabolome in non-obese diabetic mice

INTRODUCTION

Autoimmune disorders such as type 1 diabetes (T1D) are believed to be caused by the interplay between several genetic and environmental factors. Elucidation of the role of environmental factors in metabolic and immune dysfunction leading to autoimmune disease is not yet well characterized.

OBJECTIVES

Here we investigated the impact of exposure to a mixture of persistent organic pollutants (POPs) on the metabolome in non-obese diabetic (NOD) mice, an experimental model of T1D. The mixture contained organochlorides, organobromides, and per- and polyfluoroalkyl substances (PFAS).

METHODS

Analysis of molecular lipids (lipidomics) and bile acids in serum samples was performed by UPLC-Q-TOF/MS, while polar metabolites were analyzed by GC-Q-TOF/MS.

RESULTS

Experimental exposure to the POP mixture in these mice led to several metabolic changes, which were similar to those previously reported as associated with PFAS exposure, as well as risk of T1D in human studies. This included an increase in the levels of sugar derivatives, triacylglycerols and lithocholic acid, and a decrease in long chain fatty acids and several lipid classes, including phosphatidylcholines, lysophosphatidylcholines and sphingomyelins.

CONCLUSION

Taken together, our study demonstrates that exposure to POPs results in an altered metabolic signature previously associated with autoimmunity.

Antihyperglycemic and antihyperlipidemic activities of hydroethanolic extract of the fruit of Baillonella toxisperma in streptozotocin-induced diabetic rats

Objective

This work evaluated the antihyperglycemic and antihyperlipidemic activities of pulp extracts of B. toxisperma fruits in rats.

Methods

The regulatory ability of the extract on the secretory capacity of pancreatic beta cells (oral glucose tolerance test), and digestion and/or absorption of carbohydrates (starch and sucrose) were evaluated on normal Wistar rats. Diabetes was induced in Wistar rats by intravenous administration of streptozotocin (50 mg/kg), and the animals were treated by the administration of a single daily dose of 400 mg/kg BW of extract. The effect of the extract on blood glucose levels of diabetic rats was monitored 30 min, 2 h, and 5 h after administration, and on the 7th and 14th days of treatment. After 2 weeks of treatment, the rats were sacrificed, liver was preserved for the determination of glycogen content. The serum was prepared and markers for nephro and hepatotoxicity were assessed, as well as cardiovascular risk.

Results

The hydroethanolic extract of B. toxisperma fruits significantly reduced glucose concentrations after administration of starch and sucrose in normoglycemic rats by limiting the glycemic peak (increasing of 19.67% vs 27.88% for positive control and 35.96% vs 43.97% for positive control, for starch and sucrose respectively). No effect was observed after glucose administration. B. toxisperma fruits significantly decreased glucose levels by 14.5% and 54.23% respectively 30 min after administration and 7th days of treatment respectively. The extract decreased plasma triglycerides and total cholesterol levels in diabetic rats; it also decreased the cardiovascular risk through the reduction of Cardiac Risk Ratio, Atherogenic Coefficient, and non-High-Density Lipoprotein Cholesterol. The extract also promoted renal function but not structural integrity of the liver.

Conclusions

This study suggests that the hydroethanolic pulp extracts of B. toxisperma fruits are good antihyperglycemic and antihyperlipidemic properties agents and could be a potential source of compounds for diabetes management.

Clinical Aspects of Genetic and Non-Genetic Cardiovascular Risk Factors in Familial Hypercholesterolemia

Familial hypercholesterolemia (FH) is the most common monogenic metabolic disorder characterized by considerably elevated low-density lipoprotein cholesterol (LDL-C) levels leading to enhanced atherogenesis, early cardiovascular disease (CVD), and premature death. However, the wide phenotypic heterogeneity in FH makes the cardiovascular risk prediction challenging in clinical practice to determine optimal therapeutic strategy. Beyond the lifetime LDL-C vascular accumulation, other genetic and non-genetic risk factors might exacerbate CVD development. Besides the most frequent variants of three genes (LDL-R, APOB, and PCSK9) in some proband variants of other genes implicated in lipid metabolism and atherogenesis are responsible for FH phenotype. Furthermore, non-genetic factors, including traditional cardiovascular risk factors, metabolic and endocrine disorders might also worsen risk profile. Although some were extensively studied previously, others, such as common endocrine disorders including thyroid disorders or polycystic ovary syndrome are not widely evaluated in FH. In this review, we summarize the most important genetic and non-genetic factors that might affect the risk prediction and therapeutic strategy in FH through the eyes of clinicians focusing on disorders that might not be in the center of FH research. The review highlights the complexity of FH care and the need of an interdisciplinary attitude to find the best therapeutic approach in FH patients.

Aloe vera in diabetic dyslipidemia: Improving blood glucose and lipoprotein levels in pre-clinical and clinical studies

Dyslipidemia is a common feature of type 2 diabetes mellitus and is characterised by elevated triglyceride, decreased HDL cholesterol, and increased small dense LDL cholesterol levels. The underlying causes appears to be associated with insulin resistance, increased free fatty acid reflux, and low-grade inflammation, resulting in increased hepatic lipogenesis, and altered lipoprotein metabolism. Improved glycaemic control has been shown to have a positive effect on lipoprotein levels in diabetics. This can be achieved through medications/therapeutics and life style changes. Several classes of pharmacologic agents are currently in use to treat dyslipidemia. However, they may have dangerous long-term side effects, including an increased risk of liver dysfunction, weight gain, and cardiovascular diseases. Therefore, stronger alternatives with fewer side effects are required to reduce the diabetes associated complications. Many secondary plant metabolites have been shown to improve glucose homeostasis and lower lipid levels. Aloe vera and its constituents have long been used in a traditional medicine system for a diverse range of biological activities, including hypoglycaemic, antioxidant, anticarcinogenic, anti-inflammatory, and wound healing effects through various mechanisms and they have been covered well in literature. However, studies on the potential role of Aloe vera in the treatment of diabetic dyslipidemia are scanty. Therefore, in this systematic review, we focussed on the potential effect of Aloe vera and its active components in alleviating diabetic dyslipidemia, as well as their mechanism of action in pre-clinical and clinical studies.

Fasting, non-fasting and postprandial triglycerides for screening cardiometabolic risk

Fasting triacylglycerols have long been associated with cardiovascular disease (CVD) and other cardiometabolic conditions. Evidence suggests that non-fasting triglycerides (i.e. measured within 8 h of eating) better predict CVD than fasting triglycerides, which has led several organisations to recommend non-fasting lipid panels as the new clinical standard. However, unstandardised assessment protocols associated with non-fasting triglyceride measurement may lead to misclassification, with at-risk individuals being overlooked. A third type of triglyceride assessment, postprandial testing, is more controlled, yet historically has been difficult to implement due to the time and effort required to execute it. Here, we review differences in assessment, the underlying physiology and the pathophysiological relevance of elevated fasting, non-fasting and postprandial triglycerides. We also present data suggesting that there may be a distinct advantage of postprandial triglycerides, even over non-fasting triglycerides, for early detection of CVD risk and offer suggestions to make postprandial protocols more clinically feasible.

In vitro and in vivo anti-diabetic activity of Citrullus colocynthis pulpy flesh with seeds hydro-ethanolic extract

Background

Diabetes is the one of the leading cause of morbidity and mortality. Traditionally phytotherapy is widely being used for diabetes treatment and highly valued. Citrus colocynthis has known anti-diabetic potential. However, anti-diabetic potential of hydro-ethanolic extract of C. colocynthis pulpy flesh with seeds is not reported yet.

Methods

The extract of C. colocynthis pulpy flesh with seeds was done by maceration method using 70% ethanol. To evaluate anti-diabetic and antioxidant potential of the seeded fruit in vitro, α-glucosidase and DPPH inhibition assays was done, respectively. In vivo study used streptozotocin (STZ) induced diabetes model of rats. Rats were randomized in five groups i. e. normal control, negative control, standard control, C. colocynthis 150 and 300 mg/kg. STZ was administered to all groups except normal control. After wards, plant extract and glibenclamide is continued for 14 days. Blood samples were collected from rat tail vein daily and from Cardiac puncture at the end of study. The blood glucose levels were monitored daily by using one-touch blood glucose monitoring system. The blood glucose level was monitored on 0, 1st, 5th, 8th, 11th, and 14th day of induction.

Results

Hydro-ethanolic extract of C. colocynthis pulpy flesh with seeds was able to decolorize DPPH and therefore possess antioxidant potential, continuous administration for 14 days showed a marked decrease in serum glucose levels (p 0.01) it is found to be somewhat less effective as glibenclamide (standard control) (p 0.001). A time-dependent decrease in blood glucose levels was observed (351.3 ± 4 to 258 m/kg).

Conclusion

Hydro-ethanolic extract of C. colocynthis pulpy flesh with seeds lowered the serum triglyceride and cholesterol levels in diabetic rats significantly as compared to negative control. The hypoglycemic effect of hydro-ethanolic extract of C. colocynthis pulpy flesh with seeds is may be due to α-glucosidase inhibition potential.

Quinoa Seed Lowers Serum Triglycerides in Overweight and Obese Subjects: A Dose-Response Randomized Controlled Clinical Trial

Background: Quinoa (Chenopodium quinoa) is a pseudo-cereal originally cultivated in the Andean region. The popularity of its seeds has increased in recent years due to the claims of health benefits and superfood qualities. Studies to date on the health benefits of quinoa have been restricted to animal models, and the results provide weak to moderate evidence to support improved plasma lipid profiles. Clinical trials in humans to examine the claims of health benefits of quinoa are limited to a few prospective studies and one randomized trial carried out in postmenopausal women. To our knowledge, no studies have been conducted in the general population. Objective: The objective of this randomized clinical trial was to investigate the effect of different quinoa doses (25 and 50 g/d) on body composition, serum lipids and hormones, and nutrient intakes in overweight and obese humans. Methods: This was a dose-response randomized, controlled, single-blind trial with a parallel design (1 control and 2 treatment groups) that compared the effect of 25 and 50 g quinoa/d in 50 overweight and obese participants over a 12-wk intervention period. Results: Body composition, nutrient intake, and total, LDL, and HDL cholesterol were not significantly altered by quinoa consumption (P > 0.05). Mean serum triglyceride (TG) concentration was reduced significantly in the 50-g quinoa group from 1.14 to 0.72 mmol/L at 12 wk (P < 0.05). The prevalence of metabolic syndrome (MetS) was also reduced in this group by 70%. No significant changes in TGs were observed in the control and 25-g quinoa groups. The prevalence of MetS was reduced by 40% (from n = 7 at baseline to n = 4 at 12 wk) in the 25-g group. Conclusions: The consumption of 50 g quinoa/d lowers serum TGs in overweight and obese participants and reduces the prevalence of MetS. This trial was registered at clinicaltrials.gov as UTN U1111-1175-470.

Diabetes Dyslipidemia

Diabetes mellitus is associated with a considerably increased risk of premature atherosclerotic cardiovascular disease. Intensive glycemic control has essentially failed to significantly improve cardiovascular outcomes in clinical trials. Dyslipidemia is common in diabetes and there is strong evidence that cholesterol lowering improves cardiovascular outcomes, even in patients with apparently unremarkable lipid profiles. Here, the authors review the pathophysiology and implications of the alterations in lipoproteins observed in both type 1 and type 2 diabetes, the effect of medications commonly used in the management of diabetes on the lipid profile, the evidence for lifestyle and pharmaceutical interventions, and national and international recommendations for the management of dyslipidemia in patients with diabetes.

The regulation of ApoB metabolism by insulin

The leading cause of death in diabetic patients is cardiovascular disease. Apolipoprotein B (ApoB)-containing lipoprotein particles, which are secreted and cleared by the liver, are essential for the development of atherosclerosis. Insulin plays a key role in the regulation of ApoB. Insulin decreases ApoB secretion by promoting ApoB degradation in the hepatocyte. In parallel, insulin promotes clearance of circulating ApoB particles by the liver via the low-density lipoprotein receptor (LDLR), LDLR-related protein 1 (LRP1), and heparan sulfate proteoglycans (HSPGs). Consequently, the insulin-resistant state of type 2 diabetes (T2D) is associated with increased secretion and decreased clearance of ApoB. Here, we review the mechanisms by which insulin controls the secretion and uptake of ApoB in normal and diabetic livers.

Apolipoprotein B-100 and apoA-II kinetics as determinants of cellular cholesterol efflux

CONTEXT

Cellular cholesterol efflux is a key step in reverse cholesterol transport and may depend on the metabolism of apolipoprotein (apo) B-100, apoA-I, and apoA-II.

OBJECTIVE

We examined the associations between cholesterol efflux and plasma concentrations and kinetics of very low-density lipoprotein (VLDL), intermediate-density lipoprotein (IDL), and low-density lipoprotein (LDL)-apoB-100, high-density lipoprotein (HDL)-apoA-I, and HDL-apoA-II in men. DESIGN, SUBJECTS, AND METHODS: Thirty men were recruited from the community with a wide range of body mass index. The capacity of plasma and HDL to efflux cholesterol was measured ex vivo. Apolipoprotein kinetics were measured using stable isotope techniques and multicompartmental modeling.

RESULTS

Cholesterol efflux to whole plasma was correlated with plasma levels of cholesterol, triglyceride, apoB-100, insulin, cholesteryl ester transfer protein, and lecithin-cholesterol acyltransferase, body mass index and waist circumference (P < 0.05 in all). Cholesterol efflux was inversely correlated with the fractional catabolic rate (FCR) of VLDL (r = -0.728), IDL (r = -0.662), and LDL-apoB-100 (r = -0.479) but positively correlated with the FCR (r = 0.438) and production rate (r = 0.468) of HDL-apoA-II. In multiple regression analysis, the concentration and FCR of VLDL-apoB-100 (β-coefficient = 0.708 and -0.518, respectively) and IDL-apoB-100 (β-coefficient = 0.354 and -0.447, respectively) were independent predictors of cholesterol efflux. The association of cholesterol efflux with apoB-100 metabolism was diminished after removal of apoB-100-containing lipoproteins from plasma prior to efflux. All associations, except for cholesteryl ester transfer protein, were lost when cholesterol efflux to isolated HDL was tested.

CONCLUSIONS

The plasma concentration and kinetics of apoB-100-containing lipoproteins are significant predictors of the capacity of whole plasma to effect cellular cholesterol efflux.

Overweight children with type 1 diabetes have a more favourable lipid profile than overweight non-diabetic children

In the present article, we aimed to compare the cardiometabolic risk between overweight children with and without type 1 diabetes (T1DM). Therefore, data with regard to cardiometabolic risk parameters of 44 overweight Caucasian children (3-18 years) with T1DM were matched with 44 overweight peers without T1DM for sex, ethnicity, age and standard deviation score of BMI (Z-BMI). Detailed history was taken, information regarding anthropometrics and family history were collected and blood pressure was measured. Blood samples were collected for evaluation of lipid profiles (fasting in controls, non-fasting in T1DM children), alanine aminotransferase and HbA1c (in children with T1DM). It was found that overweight children with T1DM had lower median standard deviation score of waist circumference (Z-WC) as compared to the overweight control group [median, 2.0 (interquartile range, IQR, 1.5-2.3) vs. 2.6 (IQR, 2.0-2.9), P < 0.001]. After adjustment for Z-WC, in children with T1DM, median high-density lipoprotein cholesterol levels were significantly higher and median low-density lipoprotein cholesterol lower in T1DM children, as compared to their peers without T1DM [1.40 (IQR, 1.2-1.5) vs. 1.2 (IQR, 1.0-1.3) and 2.7 (IQR, 2.5-3.2) vs. 3.0 (IQR, 2.5-3.4), respectively, all P < 0.01]. When dividing children according to glycaemic status, children with suboptimal glycaemic control had higher values of triglycerides as compared to well-controlled children [1.3 (IQR, 1.0-1.8) vs. 0.96 (IQR, 0.80-1.2), P = 0.036]. In conclusion, overweight children with T1DM have a more favourable lipid profile, as compared to non-diabetic overweight controls, in spite of a higher frequency of a positive family history of CVD, T2DM and hypertension. Still, paediatricians should give extra attention to cardiometabolic risk factors within this vulnerable group, taking into account the already high cardiometabolic risk.

WITHDRAWN: Proteome and phytochemical analysis of Cynodon dactylon leaves extract and its biological activity in diabetic rats

The Publisher regrets that this article is an accidental duplication of an article that has already been published, http://dx.doi.org/10.1016/j.bionut.2010.09.001. The duplicate article has therefore been withdrawn.

A novel dihydroxy gymnemic triacetate isolated from Gymnema sylvestre possessing normoglycemic and hypolipidemic activity on STZ-induced diabetic rats

AIM OF THE STUDY

Gymnema sylvestre (Asclepiadaceae) is emerging as a potential treatment for the management of diabetes. The leaves are used in herbal medicine preparations. The present study was carried out to isolate and identify the putative antidiabetic compound based on bioassay-guided fractionation.

MATERIALS AND METHODS

An active compound dihydroxy gymnemic triacetate has been isolated from Gymnema sylvestre acetone extract and its optimum dose has been determined and patented. An optimum dose of dihydroxy gymnemic triacetate (20mg/kg body weight) was orally administered for 45 days to streptozotocin diabetic rats for the assessment of plasma glucose, insulin, glycated hemoglobin (HbA1c), tissue glycogen, lipid parameters such as triglycerides, total cholesterol, LDL-cholesterol, HDL-cholesterol and activities of hepatic marker enzymes, such as aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP) and acid phosphatase (ACP) in normal and streptozotocin diabetic rats.

RESULTS

Dihydroxy gymnemic triacetate at 20mg dose produced significant effects on all biochemical parameters studied compared to diabetic control group.

CONCLUSIONS

These results indicate that dihydroxy gymnemic triacetate, the compound from Gymnema sylvestre, possessed hypoglycemic and hypolipidemic activity in long-term treatment and hence it could be used as a drug for treating diabetes.

Hypoglycemic activity of constituents from Astianthus viminalis in normal and streptozotocin-induced diabetic mice

Astianthus viminalis has been used as a medicinal plant for a long time owing to its many physiological actions such as anti-inflammatory and antidiabetic activities. A new tetracyclic triterpenoid 3beta,19alpha-dihydroxyurs-12,20(21)-diene-28-oic acid (1), known constituents oleanolic acid (2) and ursolic acid (3), and the coumarins 7,8-dimethoxycoumarin (4) and 7-methoxycoumarin (5) were isolated from the chloroform extract of the leaves of A. viminalis. The structure and relative configurations of 1 were determined by spectroscopic methods (1H- and 13C-NMR, IR, and MS) and 2D-NMR experiments. The hypoglycemic ingredients of A. viminalis were characterized as compounds 1-3. The hypoglycemic effect of the isolated natural product 1 was investigated in normoglycemic and streptozotocin (STZ)-induced diabetic mice. All effects were compared with those of tolbutamide. Triterpenoid 1 showed potent hypoglycemic and hypolipidemic effects in the STZ-induced diabetic mice. Continuous administration of 1 (30 mg/kg, orally) led to significant decrease in the level of glucose, triglycerides, total cholesterol, LDL, and VLDL in the diabetic mice, whereas the level of HDL did not alter significantly in any of the groups studied.

Alterations in the blood glucose, serum lipids and renal oxidative stress in diabetic rats by supplementation of onion (Allium cepa. Linn)

This study examined the anti-diabetic effect of onion (Allium cepa. Linn) in the streptozotocin (STZ)-induced diabetic rats. Male Sprague-Dawley rats were divided into normal rats fed control diet or supplemented with onion powder (7% w/w) and diabetic rats fed control diet or supplemented with onion powder. Diabetes was induced by a single injection of STZ (60 mg/kg, ip) in citrate buffer. The animals were fed each of the experimental diet for 5 weeks. Blood glucose levels of rats supplemented with onion were lower than those of rats fed control diet in the diabetic rats. Onion also decreased the total serum lipid, triglyceride, and atherogenic index and increased HDL-cholesterol/total cholesterol ratio in the diabetic rats. Glutathione peroxidase, glutathione reductase and glutathione S-transferase activities were high in the diabetic rats compared to normal rats and reverted to near-control values by onion. These results indicate that onion decreased blood glucose, serum lipid levels and reduced renal oxidative stress in STZ-induced diabetic rats and this effect might exert the anti-diabetic effect of onion.

Lipid disorders in type 1 diabetes

Patients with type 1 diabetes (T1D) also present with lipid disorders. Quantitative abnormalities of lipoproteins are observed in T1D patients with poor glycaemic control (increased plasma triglycerides and low-density lipoprotein [LDL] cholesterol) or nephropathy (increased triglycerides and LDL cholesterol, low level of high density lipoprotein [HDL] cholesterol). In cases of T1D with optimal glycaemic control, plasma triglycerides and LDL cholesterol are normal or slightly decreased, while HDL cholesterol is normal or slightly increased. Several qualitative abnormalities of lipoproteins, which are potentially atherogenic, are observed in patients with T1D, even in those with good metabolic control. These abnormalities include increased cholesterol-to-triglyceride ratios within very low-density lipoprotein (VLDLs), increased triglycerides in LDLs and HDLs, compositional changes in the peripheral layer of lipoproteins, glycation of apolipoproteins, increased oxidation of LDLs and an increase in small, dense LDL particles. These qualitative changes in lipoproteins are likely to impair their function. In vitro, VLDLs and LDLs from patients with T1D induced abnormal responses in the cellular cholesterol metabolism of human macrophages. HDLs from patients with T1D are thought to be less effective in promoting cholesterol efflux from cells, and have been shown to have reduced antioxidative and vasorelaxant properties. These qualitative abnormalities are not fully explained by hyperglycaemia and may be partly due to peripheral hyperinsulinaemia associated with subcutaneous insulin administration. However, the precise consequences of these qualitative lipid changes on the development of cardiovascular disease in T1D are, as yet, unknown.

Improved metabolic control after supplemented fasting in overweight type II diabetic patients

Twenty obese type II diabetes patients were treated in a metabolic ward during 4 weeks with a very low calorie regimen (200 kcal/day). They were given dietary advice and reexamined 3 months after discharge. Mean body weight decreased by 10 kg during fasting, blood glucose was normalized, urinary glucose disappeared and the K-value at i.v. glucose tolerance test increased. Fasting serum insulin concentrations decreased by 54%. Serum triglycerides (TG) decreased by 65%, serum cholesterol (Chol) by 28% and high density lipoprotein (HDL) Chol by 14%. Three months later, only serum TG remained significantly decreased (-47%) while HDL Chol was significantly higher than on admission (+11%). Fasting blood glucose remained significantly lower (-25%) with a low urinary glucose excretion. Supplemented fasting appears to be a safe and useful tool in the treatment of obese type II diabetics. It causes, at least during a limited follow-up period, a significant improvement in glucose control and lipoprotein metabolism in spite of a concomitant reduction of the antidiabetic medication.

Antidiabetic properties of the alcoholic extract of Sphaeranthus indicus in streptozotocin-nicotinamide diabetic rats

We have investigated the possible antihyperglycaemic effects of Sphaeranthus indicus extract in rats rendered diabetic by nicotinamide (120 mgkg(-1) i.p.) and streptozotocin (STZ) (60 mgkg(-1) i.p). Fasting plasma glucose levels, serum insulin levels, serum lipid profiles, magnesium levels, glycosylated haemoglobin, changes in body weight and liver glycogen levels were evaluated in normal and diabetic rats. Oral administration of S. indicus for 15 days resulted in significant decrease in blood glucose levels and increases in hepatic glycogen and plasma insulin levels. Fasting normal rats treated with the alcoholic extract of S. indicus showed significant improvement in oral glucose tolerance test. Glibenclamide was used as a reference standard. The findings demonstrate that the alcoholic S. indicus extract may be useful in the treatment of diabetes.

The effects of oral vitamin E on induction and consequence of experimental diabetes mellitus in rats

Streptozotocin destroys the beta-cells of pancreas by generation of reactive oxygen species and vitamin E has documented antioxidant properties. To evaluate the preventive effect of vitamin E on induction of diabetes by streptozotocin and effect of oral vitamin E consumption on carbohydrate and lipid metabolism, forty male Wistar rats divided randomly to control, E1, E2 and E3 groups. The diet of E1, E2 and E3 groups were supplemented with 1, 2 and 4 g kg(-1) of vitamin E, respectively. Four days later all rats were made diabetic by IP injection of 45 mg kg-' streptozotocin and blood glucose was measured 72 h later to determine the severity of blood glucose elevation. Glycosylated hemoglobin, triglyceride, total cholesterol and HDL-c were measured and LDL-c and VIDL-c calculated in plasma of 6 diabetic rats with glucose more than 200 mg dL(-1) in each groups 21 days after streptozotocin injection. Vitamin E had no effect on diabetes induction by streptozotocin, but elevation of glycosylated Hb and reduction of LDL-c in group E3 were significant. Vitamin E also increased HDL-c although it was not statistically significant. We suggest that oral vitamin E consumption may have some beneficial effect on the correction of lipid metabolism disorders of diabetes, although it may worsen carbohydrate metabolism in mild diabetes.

Antihyperlipidemic effect of curcumin and tetrahydrocurcumin in experimental type 2 diabetic rats

Hyperlipidemia is an associated complication of diabetes mellitus. In the present study, we investigated the effect of tetrahydrocurcumin (THC), one of the active metabolites of curcumin on lipid profile in streptozotocin (STZ)-nicotinamide-induced diabetic rats. THC 80 mg/kg body weight was orally administered to diabetic rats for 45 days, resulting in a significant reduction in blood glucose and a significant increase in plasma insulin in diabetic rats, which proved that THC possess an antidiabetic effect. THC also caused a significant reduction serum and liver cholesterol, triglycerides, free fatty acids, phospholipids, HMG CoA reductase activity, very low-density lipoprotein (VLDL) and low-density lipoprotein (LDL) cholesterol levels. The decreased serum high-density lipoprotein (HDL) cholesterol in diabetic rats was also reversed toward normalization after the treatment. These biochemical observations were supplemented by histopathological examination of liver section. The effect was compared with curcumin (80 mg/kg body weight). The results showed that THC had antihyperlipidemic action in control and experimental diabetic rats. The antidiabetic and antihyperlipidemic effects of THC are more potent than those of curcumin at the same dose.

Hypoglycemic and hypolipidemic activity of ethanolic extract of Salvadora oleoides in normal and alloxan-induced diabetic rats

OBJECTIVE

To find out the hypoglycemic and hypolipidemic activity of an ethanolic extract of the aerial part of Salvadora oleoides Decne in euglycemic and alloxan-induced diabetic albino rats.

MATERIALS AND METHODS

Diabetes was induced in albino rats by administration of alloxan monohydrate (120 mg/kg, i.p.). Normal as well as diabetic albino rats were divided into groups (n = 6) receiving different treatments: vehicle (control), ethanolic extract (1 g and 2 g/kg b.w), and standard antidiabetic drug tolbutamide (0.5 g/kg b.w.). Blood samples were collected by cardiac puncture and were analyzed for blood glucose and lipid profile on days 0, 7, 14, and 21.

RESULTS

The ethanolic extract of S oleoides produced significant reduction (P < 0.001) in blood glucose and also had beneficial effects (P < 0.001) on the lipid profile in euglycemic as well as alloxan-induced diabetic rats at the end of the treatment period (21(st) day). However, the reduction in the blood glucose and improvement in lipid profile was less than that achieved with the standard drug tolbutamide.

CONCLUSION

We concluded that an ethanolic extract of S oleoides is effective in controlling blood glucose levels and improves lipid profile in euglycemic as well as diabetic rats.

Effect of tetrahydrocurcumin on lipid peroxidation and lipids in streptozotocin-nicotinamide-induced diabetic rats

Hyperlipidaemia is an associated complication of diabetes mellitus. We recently reported that tetrahydrocurcumin lowered the blood glucose in diabetic rats. In the present study, we have investigated the effect of tetrahydrocurcumin, one of the active metabolites of curcumin on lipid profile and lipid peroxidation in streptozotocin-nicotinamide-induced diabetic rats. Tetrahydrocurcumin 80 mg/kg body weight was administered orally to diabetic rats for 45 days, resulted a significant reduction in blood glucose and significant increase in plasma insulin in diabetic rats, which proved its antidiabetic effect. Tetrahydrocurcumin also caused a significant reduction in lipid peroxidation (thiobarbituric acid reactive substances and hydroperoxides) and lipids (cholesterol, triglycerides, free fatty acids and phospholipids) in serum and tissues, suggesting its role in protection against lipid peroxidation and its antihyperlipidemic effect. Tetrahydrocurcumin showed a better effect when compared with curcumin. Results of the present study indicate that tetrahydrocurcumin showed antihyperlipidaemic effect in addition to its antidiabetic effect in type 2 diabetic rats.

Combined effect of probucol and insulin on renal damage in diabetic rats fed a high cholesterol diet

We investigated the effects of long-term treatment with probucol, a hypolipidemic agent with antioxidative action, insulin, or their combination on renal damage in streptozotocin-induced diabetic rats fed a high cholesterol diet. Increases in urinary albumin and lipid peroxide excretions were observed in these diabetic rats, when both urinary parameters were measured at 8 and 15 weeks after streptozotocin administration. Daily treatment with probucol, insulin, or their combination markedly suppressed the increase in the 24 h urinary albumin and lipid peroxide excretions. Furthermore, glycogen degeneration of distal tubules, fatty degeneration of glomerular endothelium, and hypertrophy of glomeruli and mesangium were observed in the kidneys of the diabetic animals, when histopathological evaluation was performed at 4, 8 and 15 weeks (glomerular and mesangial hypertrophy was observed only at 15 weeks). Combined probucol and insulin treatment was the most effective in suppressing these renal histopathological changes. These results indicate that combined treatment with probucol and insulin is useful in preventing the progression of renal damage in diabetic rats. The possible mechanisms for the preventive effect of this combined treatment will be discussed.

Hypoglycaemic activity of Pterocarpus marsupium Roxb

The antidiabetic activity of various subfractions of the alcohol extract of the bark of Pterocarpus marsupium Roxb. was evaluated in alloxan-induced diabetic rats. The effect of these extracts on lipid profile and liver function tests were also assessed to evaluate their activity in controlling diabetes related metabolic alterations. The parameters measured were plasma glucose, total protein, cholesterol, triglycerides, alkaline phosphatase, SGOT and SGPT. The results indicate the effective role of Pterocarpus marsupium on the above mentioned parameters indicating that Pterocarpus marsupium can also control the diabetes related metabolic alterations apart from controlling the glucose levels. Among the fractions tested the butanol subfraction was found to be more active in comparison with other subfractions. It can be concluded that the butanol subfraction of the alcohol extract of Pterocarpus marsupium exhibits significant antidiabetic activity and corrects the metabolic alterations in diabetic rats and this activity may resemble insulin-like properties.

NO-1886 upregulates ATP binding cassette transporter A1 and inhibits diet-induced atherosclerosis in Chinese Bama minipigs

It is widely believed that high density lipoprotein-cholesterol (HDL-C) functions to transport cholesterol from peripheral cells to the liver by reverse cholesterol transport (RCT), a pathway that may protect against atherosclerosis by clearing excess cholesterol from arterial cells. A cellular ATP binding cassette transporter called ABCA1 mediates the first step of RCT. NO-1886 has been proven to be highly effective at increasing HDL-C and reducing atherosclerosis. However, the mechanism of atherosclerosis inhibition for NO-1886 is not fully understood. In this study, the effects of NO-1886 on ABCA1 were investigated in high-fat/high-sucrose/high-cholesterol-fed Chinese Bama minipigs. Administration of NO-1886 (0.1 g/kg body weight/day) in the diet for 5 months significantly reduced atherosclerosis lesions and significantly increased plasma HDL-C and apolipoprotein A-I levels. The mRNA and protein levels of ABCA1 in the liver, retroperitoneal adipose tissue, and aorta were increased by NO-1886 as well. Multivariate linear regression analysis showed that the levels of LPL in plasma and the levels of ABCA1 in aorta were independently associated with the atherosclerotic lesion area. In addition, NO-1886 upregulated liver X receptor alpha and affected the expression of scavenger receptor class B type I in the liver. These results demonstrate that the mechanism of atherosclerosis inhibition for NO-1886 is associated with its effect on ABCA1.

Oxandrolone enhances skeletal muscle myosin synthesis and alters global gene expression profile in Duchenne muscular dystrophy

Earlier studies have shown that the progressive, unrelenting muscle loss associated with Duchenne muscular dystrophy (DMD) involves an imbalance between the rates of synthesis and degradation of muscle proteins. Although previous studies have suggested that oxandrolone may be beneficial in DMD, the mechanism of action of oxandrolone on muscle in DMD remains unclear. To address these issues, we combined stable isotope studies and gene expression analysis to measure the fractional synthesis rate of myosin heavy chain (MHC), the key muscle contractile protein, the transcript levels of the isoforms of MHC, and global gene expression profiles in four children with DMD before and after 3 mo of treatment with oxandrolone. Gastrocnemius muscle biopsies and blood samples were collected during the course of a primed 6-h continuous infusion of l-[U-(13)C]leucine on two separate occasions, before and after the 3-mo treatment with oxandrolone (0.1 mg.kg(-1).day(-1)). Gene expression analysis was done with microarrays and RT-qPCR. In response to the treatment, MHC synthesis rate increased 42%, and this rise was accounted for, at least in part, by an upregulation of the transcript for MHC8 (perinatal MHC). Gene expression data suggested a decrease in muscle regeneration as a consequence of oxandrolone therapy, presumably because of a decrease in muscle degeneration. These findings suggest that 1) oxandrolone has a powerful protein anabolic effect on a key contractile protein and 2) larger and longer-term studies are warranted to determine whether these changes translate into meaningful therapy for these patients.

Effects of bis(alpha-furancarboxylato)oxovanadium(IV) on non-diabetic and streptozotocin-diabetic rats

BACKGROUND

Bis(alpha-furancarboxylato)oxovanadium(IV) (BFOV), a new orally active anti-diabetic vanadium complex with organic agent, has been synthesized and characterized. The current study examined the stability in aqueous solution and effects of the complex on carbohydrate and lipid metabolism in non-diabetic and streptozotocin-induced diabetic rats.

METHODS

Diabetic rats were induced by a single dose injection of streptozotocin (STZ, 50 mg/kg body weight, i.p.). The rats were randomly divided into non-diabetic (control, CON), diabetic (DM) and BFOV (0.2 mmol/kg body weight)-treated, diabetic-BFOV (0.1, 0.2 and 0.4 mmol/kg body weight) groups. All substances were given intragastrically to non-diabetic and STZ-induced diabetic rats for 4 weeks. Blood glucose concentration was monitored during administration and, at the end of experiment glycosylated hemoglobin, serum insulin, lipid concentrations and glycogen content were observed.

RESULTS

Administration of BFOV to STZ-diabetic rats dose-dependently reduced blood glucose concentration when compared to diabetic rats (P<0.01), but it did not influence blood glucose in non-diabetic rats. Serum insulin concentrations were not increased in the BFOV-treated diabetic groups and, in contrast, significantly lowered in the 0.2 mmol/kg body weight BFOV-treated non-diabetic group at the end of experiment. Moreover, BFOV markedly reduced glycosylated hemoglobin concentration and improved dyslipidemia in STZ-diabetic rats, in a dose-dependent manner (P<0.05, P<0.01), but had no significant effect on non-diabetic rats.

CONCLUSION

The organic vanadium complex was found to effectively attenuate diabetic alterations in STZ-diabetic rats.

Combined effect of probucol and insulin on cataracts of diabetic rats fed a high cholesterol diet

We investigated the effects of long-term treatment with probucol, a hypolipidemic agent with antioxidative action, insulin, or their combination on cataracts of streptozotocin-induced diabetic rats fed a high cholesterol diet. Each rat was checked for cataracts at 0, 1, 2, 4, 8, 12 and 15 weeks after streptozotocin injection. Cataracts were observed from 8 weeks in untreated hypercholesterolemic and diabetic rats and the incidence of catarats increased to 100% by 15 weeks. The incidence of cataracts in rats treated with probucol, insulin and their combination was first seen at 12, 12 and 15 weeks, respectively, and was 86%, 63% and 33%, respectively, at 15 weeks. The preventive effects of both agents alone and their combination on the cataracts were confirmed by histopathological evaluation of eyeballs. The combined treatment with both agents markedly improved hyperglycemia, hyperlipidemia and increased serum lipid peroxide levels. These results indicate that the combined treatment with probucol and insulin is useful in preventing the development and progression of diabetic cataracts.

A minipig model of high-fat/high-sucrose diet-induced diabetes and atherosclerosis

Summary Type 2 diabetes is a major risk factor of the development of atherosclerosis in humans. However, studies examining mechanisms underlying diabetes-accelerated atherosclerosis have been limited by the lack of suitable humanoid animal models. Pigs have a cardiovascular system that is very similar to that of humans and is useful as a model for human physiology and pathophysiology. In this study, we established a new miniature pig model for studying dyslipidaemia and atherosclerosis in diabetes. Chinese Guizhou minipigs were fed a normal control diet or a high-fat/high-sucrose diet (HFSD) for 6 months. Plasma total cholesterol (TC), high-density lipoprotein cholesterol, triglyceride (TG), insulin and glucose were quantified at monthly intervals. The induction of insulin resistance and dysfunction of the pancreatic beta-cell were assessed by oral glucose tolerance test and insulin sensitivity test. The aortic fatty streak lesions were quantified following lipid staining with Sudan IV. During the feeding period, mild high plasma TC and TG were induced. At the end of 6 months, in HFSD-fed animals, the adipocytes were hypertrophic, fat deposit in the liver was observed, loss of pancreatic beta-cells was observed, and the aortic fatty streak lesions were clearly present in the animals' aortas. Our study established that miniature pigs that were fed a HFSD without adding dietary cholesterol developed insulin resistance, mild diabetes and atherosclerotic lesions. HFSD-fed miniature pigs may be good animal models for research on the treatment of diabetic dyslipidaemia complicated with atherosclerosis.

Attenuation of hyperglycemia and associated biochemical parameters in STZ-induced diabetic rats by dietary supplementation of potato peel powder

BACKGROUND

Both dietary fiber and polyphenols have been reported to exert antihyperglycemic effect. Potato peel (PP), a waste by product of potato processing, is found to be a good source of both dietary fiber and polyphenols. The current study examined the attenuating influence of dietary potato peel (PP) powder on hyperglycemia and various oxidative stress-associated biochemical parameters in diabetic rats.

METHODS

Streptozotocin (STZ)-induced diabetic male Wistar rats were used as experimental models. The rats were divided into nondiabetic (control), diabetic, potato-peel-supplemented (5% and 10%) and diabetic-PP (5% and 10%)-supplemented groups and were maintained for 4 weeks on the experimental regime. The modulatory role of PP was assessed by determining its effect on blood glucose, urine output, body weight gain, lipid peroxidation, reduced glutathione, serum aminotransferases, lipid profiles, selected antioxidant enzymes in liver/kidney and selected eye lens parameters.

RESULTS

Diabetic rats fed with PP-powder-supplemented diet for 4 weeks showed a significant decrease in blood glucose levels. Incorporation of PP powder reduced significantly the hypertrophy of both liver and kidney of STZ-diabetic rats and also normalized the activities of serum ALT and AST, hepatic and renal MDA and GSH, as well as activities of various antioxidant enzymes in liver and kidney of diabetic rats. Furthermore, PP powder in the diet also appeared to attenuate the eye lens damage associated with the diabetic condition.

CONCLUSION

Potato peel powder supplementation in diet was found to effectively attenuate diabetic alterations in rats.

Antidiabetic activity of alcoholic stem extract of Coscinium fenestratum in streptozotocin-nicotinamide induced type 2 diabetic rats

The antidiabetic potential of the alcoholic stem extract of Coscinium fenestratum Colebr. (Menispermaceae), a medicinal plant widely used in the traditional Ayurveda and Siddha systems of medicine for the treatment of diabetes mellitus was evaluated in the STZ-nicotinamide induced type 2 diabetic model. Graded doses of the alcoholic stem extract were administered to normal and experimental diabetic rats for 12 days. Significant (p < 0.05) reduction in fasting blood glucose levels were observed in the normal as well as in the treated diabetic animals. Serum insulin levels were not stimulated in the animals treated with the extract. In addition, changes in body weight, serum lipid profiles, thiobarbituric acid reactive substance levels, glycosylated hemoglobin and liver glycogen levels assessed in the extract treated diabetic rats were compared with diabetic control and normal animals. Significant results were observed in the estimated parameters, thereby justifying the use of the plant in the indigenous system of medicine.

Fruit of the jambolan tree (Eugenia jambolana Lam.) and experimental diabetes

The fruit of Indian Eugenia jambolana have been shown to have therapeutic properties, but because the therapeutic potential of a plant is related to the geographic region in which the plant was grown and to the part of the plant used, we investigated Brazilian Eugenia jambolana fruit using the same preparation and experimental methods as have been used in India. The well-established metabolic cage model was used to evaluate the physiological and metabolic parameters associated with streptozotocin-induced diabetes in rats (n=10) which had been administered, by gavage, 50 mg per day of lyophilised Eugenia jambolana fruit-pulp extract for 41 days. We found that, compared to untreated controls, rats treated with the lyophilised fruit-pulp showed no observable difference in body weight, food or water intake, urine volume, glycaemia, urinary urea and glucose, hepatic glycogen, or on serum levels of total cholesterol, HDL cholesterol or triglycerides. No change was observed in the masses of epididymal or retroperitoneal adipose tissue or of soleus or extensor digitorum longus muscles. This lack of any apparent effect on the diabetes may be attributable to the regional ecosystem where the fruit was collected and/or to the severity of the induced diabetes.

Combined effect of vitamin E and insulin on cataracts of diabetic rats fed a high cholesterol diet

In the present study we investigated the effects of a long-term treatment with vitamin E, an antioxidant vitamin, insulin or their combination on cataracts of streptozotocin (STZ)-induced diabetic rats fed a high cholesterol diet. Each rat was checked for cataracts at 0, 1, 2, 4, 8, 12 and 15 weeks after STZ injection. Cataracts were observed from 8 weeks in the control diabetic rats and their incidence of catarats increased to 100% by 12 weeks. The incidence of cataracts in rats treated with vitamin E, insulin and their combination was first seen at 12 weeks and 56%, 20% and 10%, respectively, at 12 weeks and 78%, 50% and 20%, respectively, at 15 weeks. The preventive effects of either agent alone and their combination on the cataracts were in agreement with those obtained by histopathological evaluation of eyeballs. The combined treatment with both agents markedly improved hyperglycemia, hyperlipidemia and increased serum lipid peroxide levels. These results indicate that the combined treatment with vitamin E and insulin is useful in preventing the development and progression of diabetic cataracts.

Effect of Combined Vitamin E and Insulin Administration on Renal Damage in Diabetic Rats Fed a High Cholesterol Diet

In the present study, we investigated the effects of a long-term treatment with vitamin E, an antioxidant vitamin, insulin, or their combination on renal damage in streptozotocin (STZ)-induced diabetic rats fed a high cholesterol diet. Increases in urinary albumin and lipid peroxide (LPO) excretions were observed in these diabetic rats, when both urinary parameters were measured at 8 and 15 weeks after STZ administration. Daily treatment with vitamin E, insulin, or their combination markedly suppressed the increase in the 24 h urinary albumin and lipid peroxide excretions. Furthermore, glycogen degeneration of distal tubules, fatty degeneration of glomerular endothelium and hypertrophy of glomeruli and mesangium were observed in the kidneys of the diabetic animals when histopathological evaluation was performed at 4, 8, and 15 weeks (glomerular and mesangial hypertrophy were observed only at 15 weeks). Combined vitamin E and insulin treatment was the most effective at suppressing these renal histopathological changes. These results indicate that combined vitamin E and insulin treatment additively prevents the development and progression of renal damage in diabetic rats. Possible mechanisms for the preventive effect of this combined treatment are discussed.

Dyslipidemia in type 2 diabetes

Type 2 diabetes mellitus is associated with a cluster of lipid abnormalities:elevated plasma triglycerides, reduced high-density lipoprotein cholesterol, and smaller and denser low-density lipoproteins,which have been associated with an increased risk of cardiovascular disease. Insulin resistance may contribute to dyslipidemia associated with type 2 diabetes by increasing hepatic secretion of large,triglyceride-rich very low-density lipoprotein particles and by impairing the clearance of lipoprotein particles from plasma. Lifestyle interventions may be effective in improving the diabetic dyslipidemia syndrome. For patients who do not respond to lifestyle changes, pharmacologic therapies (lipid-lowering medications and anti-diabetic agents) are available. Clinical trials demonstrate that the use of such pharmaceutics to treat diabetic dyslipidemia concomitantly reduces the risk of coronary artery disease.

Antidiabetic activity of aqueous leaf extract of Annona squamosa in streptozotocin-nicotinamide type 2 diabetic rats

The claim by some tribal populations in parts of Northern India that the young leaves of the custard apple tree, Annona squamosa L. (Annonaceae) has antidiabetic properties was investigated. Diabetes mellitus was induced with streptozotocin-nicotinamide and graded doses of the aqueous leaf extracts were then administered in drinking water to normal and experimental diabetic rats for 12 days. Fasting plasma glucose levels, serum insulin levels, serum lipid profiles and changes in body weight were evaluated in normal rats while liver glycogen levels and pancreatic TBARS levels were evaluated additionally in diabetic rats. The diabetic groups treated with the aqueous leaf extract were compared with standard glibenclamide. The findings of the study support the antidiabetic claims of Annona squamosa.