The effects of tolbutamide on lipoproteins, lipoprotein lipase and hormone-sensitive lipase

Transfer of Proteins from Cultured Human Adipose to Blood Cells and Induction of Anabolic Phenotype Are Controlled by Serum, Insulin and Sulfonylurea Drugs

Glycosylphosphatidylinositol-anchored proteins (GPI-APs) are anchored at the outer leaflet of eukaryotic plasma membranes (PMs) only by carboxy-terminal covalently coupled GPI. GPI-APs are known to be released from the surface of donor cells in response to insulin and antidiabetic sulfonylureas (SUs) by lipolytic cleavage of the GPI or upon metabolic derangement as full-length GPI-APs with the complete GPI attached. Full-length GPI-APs become removed from extracellular compartments by binding to serum proteins, such as GPI-specific phospholipase D (GPLD1), or insertion into the PMs of acceptor cells. Here, the interplay between the lipolytic release and intercellular transfer of GPI-APs and its potential functional impact was studied using transwell co-culture with human adipocytes as insulin-/SU-responsive donor cells and GPI-deficient erythroleukemia as acceptor cells (ELCs). Measurement of the transfer as the expression of full-length GPI-APs at the ELC PMs by their microfluidic chip-based sensing with GPI-binding α-toxin and GPI-APs antibodies and of the ELC anabolic state as glycogen synthesis upon incubation with insulin, SUs and serum yielded the following results: (i) Loss of GPI-APs from the PM upon termination of their transfer and decline of glycogen synthesis in ELCs, as well as prolongation of the PM expression of transferred GPI-APs upon inhibition of their endocytosis and upregulated glycogen synthesis follow similar time courses. (ii) Insulin and SUs inhibit both GPI-AP transfer and glycogen synthesis upregulation in a concentration-dependent fashion, with the efficacies of the SUs increasing with their blood glucose-lowering activity. (iii) Serum from rats eliminates insulin- and SU-inhibition of both GPI-APs' transfer and glycogen synthesis in a volume-dependent fashion, with the potency increasing with their metabolic derangement. (iv) In rat serum, full-length GPI-APs bind to proteins, among them (inhibited) GPLD1, with the efficacy increasing with the metabolic derangement. (v) GPI-APs are displaced from serum proteins by synthetic phosphoinositolglycans and then transferred to ELCs with accompanying stimulation of glycogen synthesis, each with efficacies increasing with their structural similarity to the GPI glycan core. Thus, both insulin and SUs either block or foster transfer when serum proteins are depleted of or loaded with full-length GPI-APs, respectively, i.e., in the normal or metabolically deranged state. The transfer of the anabolic state from somatic to blood cells over long distance and its "indirect" complex control by insulin, SUs and serum proteins support the (patho)physiological relevance of the intercellular transfer of GPI-APs.

Quantitative NMR-Based Lipoprotein Analysis Identifies Elevated HDL-4 and Triglycerides in the Serum of Alzheimer’s Disease Patients

Alzheimer’s disease (AD) is the most common form of dementia in the elderly and has been associated with changes in lipoprotein metabolism. We performed quantitative lipoprotein analysis in a local cohort of cognitively impaired elderly and control subjects using standardized nuclear magnetic resonance (NMR) spectroscopy. A commercially available quantitative NMR-based assay covering 112 lipoprotein main and subtype variables was used to investigate blood serum samples from a moderate cohort size of 161 persons (71 female, 90 male), including measures of quality control. Additionally, clinical metadata and cerebrospinal fluid AD biomarkers were collected and used for analysis. High-density lipoprotein (HDL) HDL-4 subfraction levels were mostly high in female individuals with mild cognitive impairment (MCI), followed by AD. Low-density lipoprotein (LDL) LDL-2 cholesterol was slightly elevated in male AD patients. HDL-2 apolipoprotein Apo-A1, HDL-2 phospholipids, and HDL-3 triglycerides were highly abundant in AD and MCI women compared to men. When considering clinical biomarkers (Aβ, tau), very low-density lipoprotein (VLDL) VLDL-1 and intermediate-density lipoprotein (IDL) triglycerides were substantially higher in AD compared to MCI. In addition, triglyceride levels correlated positively with dementia. Different lipoprotein serum patterns were identified for AD, MCI, and control subjects. Interestingly, HDL-4 and LDL-2 cholesterol parameters revealed strong gender-specific changes in the context of AD-driven dementia. As gender-based comparisons were based on smaller sub-groups with a low n-number, several statistical findings did not meet the significance threshold for multiple comparisons testing. Still, our finding suggests that serum HDL-4 parameters and various triglycerides correlate positively with AD pathology which could be a read-out of extended lipids traveling through the blood-brain barrier, supporting amyloid plaque formation processes. Thereof, we see herein a proof of concept that this quantitative NMR-based lipoprotein assay can generate important and highly interesting data for refined AD diagnosis and patient stratification, especially when larger cohorts are available.

Protective effects of Artemisia judaica extract compared to metformin against hepatorenal injury in high-fat diet/streptozotocine-induced diabetic rats

Diabetes mellitus (DM) is one of the most dangerous incurable diseases that affects a large number of people worldwide. Artemisia species have various protective activities and are widely used for the control of diabetes in folkloric medicine. Therefore, the current study was designed to illustrate the protective effect of oral administration of Artemisia judaica extract (AjE) against hepatorenal damage in a high-fat diet/streptozotocin (HFD/STZ) rat model of hyperlipidemia and hyperglycemia. Animals were divided into five groups-control, AjE, HFD/STZ, HFD/STZ-AjE (300 mg/kg), and HFD/STZ-MET (100 mg/kg)-and treated daily for 28 days. The results revealed that STZ-injected rats showed marked hyperglycemia and hypoinsulinemia in addition to high levels of cholesterol, triglycerides, and low- and high-density lipoproteins compared to control rats. Significant elevations in hepatic (AST and ALT) and renal (urea, uric acid, and creatinine) function markers were observed in the serum of diabetic rats. Additionally, STZ injection caused remarkable elevations in lipid peroxidation and nitric oxide levels as well as suppression of antioxidant markers (superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, and glutathione). Marked elevations in TNF-α and Bax levels with a decline in Bcl-2 levels were detected after STZ injection. Furthermore, TGF-β1 expression levels were significantly upregulated in the liver and kidney tissues. Rats that received AjE or MET showed significant improvement in most of the aforementioned parameters, and the protective efficacy was higher for AjE than for MET. Histopathological screening confirmed the biochemical findings. Conclusively, our results illustrated the antihyperglycemic, antihyperlipidemic, antioxidant, anti-inflammatory, and antiapoptotic activities of AjE against hepatorenal injury in HFD/STZ-induced diabetes.

Folic acid and melatonin mitigate diabetic nephropathy in rats via inhibition of oxidative stress

Background

Diabetes mellitus is a global epidemic leads to multiple serious health complications, including nephropathy. Diabetic nephropathy is a serious kidney-related complication of type 1 or 2 diabetes that is prevalent in almost 40% of the people with diabetes. We examined whether folic acid and melatonin can reduce progression of nephropathy in rats of type 1 diabetes mellitus by controlling the level of oxidative stress, glucose, lipids, and cytokines.

Methods

Forty-two male albino rats were distributed into six groups, (n = 7 per group). Five of the groups were induced with diabetes by a single intraperitoneal injection of freshly prepared streptozotocin at a dose of 50 mg/kg body weight. After the induction of diabetes, the rats were treated with folic acid (100 mg/kg) and melatonin (10 mg/kg) separately and in combination daily for 6 weeks, whereas, the other diabetic group was treated with glibenclamide (5 mg/kg). One of the diabetic groups served as a positive control. One-way ANOVA was used to compare those five subfields ability followed by LSD multiple comparisons.

Results

The data indicated that diabetes significantly altered the body weight, lipids and kidney function. Diabetic rats exhibited a significant increase in plasma levels of urea, uric acid, creatinine, sodium, tumor necrosis factor alpha (TNF-α), interleukin-6(IL-6), cholesterol, triglycerides, and low-density lipoprotein (LDL). In contrast, plasma total protein, potassium, high-density lipoprotein (HDL) and interleukin-10 (IL-10) decreased significantly in diabetic rats compared to the control rats. Moreover, levels of renal malondialdehyde (MDA) and nitric oxide (NO) were significantly increased while the levels of renal glutathione(GSH), superoxide dismutase(SOD), and catalase (CAT) were significantly decreased in diabetic rats comparison to those in the control rats. Hence, diabetic rats treated with folic acid and melatonin alone as well as in combination showed improvements with respect to the indices in addition to a significant recovery observed via histopathology when compared to the diabetic group.

Conclusions

These results revealed that treatment with folic acid in combination with melatonin in diabetic rats was more effective than treatment with either of folic acid or melatonin alone to alleviate the symptoms of diabetic nephropathy.

Efficacy of a Methanolic Extract of Adansonia digitata Leaf in Alleviating Hyperglycemia, Hyperlipidemia, and Oxidative Stress of Diabetic Rats

Traditionally, in many countries, various parts of the Adansonia digitata (A. digitata) tree have been used in the treatment of many clinical ailments including diarrhea and dysentery. The phytochemical screening has indicated that the leaf extract of A. digitata contains flavonoids, saponins, mucilage, steroids, and alkaloids. Thus, this paper aims to evaluate the hyperglycaemic and hypolipidaemic effects of methanolic extract of A. digitata leaves (200 mg/kg and 400 mg/kg) in diabetic rats. The extract was administered orally for six weeks in the streptozotocin (STZ)-induced diabetic rats. The treatment with the extract caused a significant reduction in the blood glucose, glycosylated hemoglobin, cholesterol, triglycerides, low-density lipoprotein (LDL), interleukin 6 (IL-6), tumor necrosis factor-alpha (TNF-α), and malondialdehyde (MDA) levels by 46.7%, 46.15%, 48.91%, 43%, 60%, 66%, 45.45%, and 30.4%, respectively, as compared to the diabetic group after the sixth week of treatment. The leaf extract also mitigated the decline of high-density lipoprotein (HDL) level, RBCs count, hemoglobin level, packed cell volume (PCV %), and erythropoietin concentration in diabetic rats by 31%, 33.25%, 24.72%, 51.42%, and 220.68% with respect to the diabetic group. Also, the extract maintained the level of antioxidant enzymes, catalase (CAT) and superoxide dismutase (SOD), and reduced glutathione (GSH) in the diabetic rats. It also reduced the elevation in the white blood corpuscles (WBC) count in the STZ-induced diabetic rats. Our study, therefore, indicates that methanolic extract of A. digitata leaf exerts strong antidiabetic and hypolipidaemic properties in a dose-dependent manner by improving the hematological properties and redox parameters in the experimental diabetic rats.

Action of corilagin on hyperglycemia, hyperlipidemia and oxidative stress in streptozotocin-induced diabetic rats

Diabetes mellitus is the world's most common endocrine disease involving metabolic disorders of carbohydrate, protein and fat. This study was undertaken to investigate the anti-diabetic activity of corilagin, a member of polyphenolic tannins used against hyperglycemia and many other diseases in well-known animal models. Diabetes was induced chemically by intraperitoneal administration of Streptozotocin (40 mg/kg bw) to albino Wistar rats. Diabetic rats showed significant increase in the levels of fasting blood glucose, glycated haemoglobin, total cholesterol, triglyceride, low density lipoprotein cholesterol, very low density lipoprotein cholesterol, and a significant decrease in the level of body weight, plasma insulin, high density lipoprotein cholesterol, antioxidant activities, viz. superoxide dismutase, catalase and reduced glutathione when compared to controls. However, after 30 days of oral administration of corilagin (10 and 20 mg/kg bw/day) to these diabetic rats evoked significant alterations in the above mentioned parameters. The effect of corilagin was compared with the standard drug, glibenclamide (0.1 mg/kg body weight/day). Thus, the present study suggests that the corilagin acts as a natural, effective therapeutic agent to regulate diabetes, by exhibiting antidiabetic, antihyperlipidemic and antioxidant properties in STZ induced diabetic rats.

Antihyperglycemic and antihyperlipidemic effects of hydroalcoholic extract of Securigera securidaca seeds in streptozotocin-induced diabetic rats

Background:

Hyperlipidemia is an associated complication of diabetes mellitus. Lowering of serum lipid levels seems to be associated with a decrease in the risk of vascular disease and related complications. The purpose of the current study was to evaluate the antihyperglycemic and antihyperlipidemic effects of the hydroalcoholic extract of Securigera securidaca seeds in streptozotocin-induced diabetic rats.

Materials and Methods:

Female Wistar rats were randomly divided into four groups as follows: Control, diabetic, and diabetic rats treated with the Securigera extract at doses of 100 and 200 mg/kg. The animals were rendered diabetic by a single intraperitoneal injection of 55 mg/kg streptozotocin. Diabetic rats received the Securigera extract daily in drinking water from the day on which diabetes was confirmed for 4 weeks. The levels of serum glucose and lipids were spectrophotometrically measured in all groups at weeks 0 (before diabetes induction), 2, and 4.

Results:

The results showed that there was a significant increase in serum glucose, triglycerides, total cholesterol, and low density lipoprotein (LDL)-cholesterol in streptozotocin-induced diabetic rats, accompanied by a decrease in high density lipoprotein (HDL)-cholesterol. Treatment of diabetic rats with S. securidaca seed extract at a dose of 200 mg/kg over a 4-week period significantly reduced the levels of serum glucose, total cholesterol, and LDL-cholesterol and increased the level of HDL-cholesterol, compared to diabetic untreated rats.

Conclusions:

Securigera extract at a dose of 200 mg/kg exhibited hypoglycemic and hypolipidemic activities in streptozotocin-diabetic rats during the 4-week treatment period. This provides a valid scientific basis for using it in the treatment of diabetes in Iranian folk medicine.

RETRACTED: Combination of carvacrol and rosiglitazone ameliorates high fat diet induced changes in lipids and inflammatory markers in C57BL/6J mice

This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/our-business/policies/article-withdrawal). This article has been retracted at the request of the Editor-in-Chief. Following concerns raised by Dr. E. Bik, the journal conducted an investigation and found evidence that there had been improper manipulation and duplication of images in Figure 4. The editors would like to thank Dr. Bik for her valuable insight in this matter. The authors have not responded to requests for an explanation of these irregularities so this article is retracted without their approval.

Protective role of 20-OH ecdysone on lipid profile and tissue fatty acid changes in streptozotocin induced diabetic rats

Hyperlipidemia is an associated complication of diabetes mellitus. The association of hyperglycemia with an alteration of lipid parameters presents a major risk for cardiovascular complications in diabetes. The present study was designed to examine the antihyperlipidemic effect of 20-OH ecdysone on lipid profile and tissue fatty acid changes in streptozotocin induced diabetic rats. The levels of blood glucose, cholesterol, triglycerides, free fatty acids, phospholipids, low density lipoprotein, very low density lipoprotein, high density lipoprotein, lipoprotein lipase, lecithin cholesterol acyl transferase, 3-hydroxy 3-methylglutaryl coenzyme A reductase and fatty acid composition were estimated in plasma, liver and kidneys of control and experimental groups of rats. Oral administration of 20-OH ecdysone at a dose of 5mg/kg bodyweight per day to STZ-induced diabetic rats for a period of 30 days resulted in a significant reduction in fasting blood glucose, cholesterol, triglycerides, free fatty acids, phospholipids, low density lipoprotein, very low density lipoprotein, 3-hydroxy 3-methylglutaryl coenzyme A reductase and elevation of high density lipoprotein, lipoprotein lipase and lecithin cholesterol acyl transferasein comparison with diabetic untreated rats. Moreover, administration of 20-OH ecdysone to diabetic rats also decreased the concentrations of fatty acids, viz., palmitic, stearic (16:1) and oleic acid (18:1), whereas linolenic (18:3) and arachidonic acid (20:4) were elevated. The antihyperlipidemic effect of 20-OH ecdysone was compared with glibenclamide a well-known antihyperglycemic drug. The result of the present study indicates that 20-OH ecdysone showed an antihyperlipidemic effect in addition to its antidiabetic effect in experimental diabetes.

The Driselase-treated fraction of rice bran is a more effective dietary factor to improve hypertension, glucose and lipid metabolism in stroke-prone spontaneously hypertensive rats compared to ferulic acid

The aim of this study is to investigate the effects of dietary supplementation with the Driselase-treated fraction (DF) of rice bran and ferulic acid (FA) on hypertension and glucose and lipid metabolism in stroke-prone spontaneously hypertensive rats (SHRSP). Male SHRSP at 4 weeks of age were divided into three groups, and for 8 weeks were fed (1) a control diet based on AIN-93M, (2) a DF of rice bran-supplemented diet at 60 g/kg and (3) an FA-supplemented diet at 0.01 g/kg. Means and standard errors were calculated and the data were tested by one-way ANOVA followed by a least significance difference test. The results showed that both the DF and FA diets significantly improved hypertension as well as glucose tolerance, plasma nitric oxide (NOx), urinary 8-hydroxy-2'-deoxyguanosine and other parameters. In particular, compared to the FA diet, the DF diet produced a significant improvement in urinary NOx, hepatic triacylglycerol and several mRNA expressions of metabolic parameters involved in glucose and lipid metabolisms. The results of the metabolic syndrome-related parameters obtained from this study suggest that the DF diet is more effective than the FA diet.

POSSIBLE ANTIDIABETIC AND ANTIHYPERLIPIDAEMIC EFFECT OF FERMENTED PARKIA BIGLOBOSA (JACQ) EXTRACT IN ALLOXAN-INDUCED DIABETIC RATSs

1. The hypoglycaemic effect of fermented seeds of Parkia biglobosa (PB; African locust bean), a natural nutritional condiment that features frequently in some African diets as a spice, was investigated in the present study in alloxan-induced diabetic rats. Its effect was compared with that of glibenclamide (Daonil; Sanofi-Aventis, Paris, France), a reference antidiabetic drug. The effects of PB on lipid profiles were also examined. 2. In order to assess the hypoglycaemic and hypolipidaemic effects of aqueous and methanolic extracts of PB on experimental animals, fasting plasma glucose (FPG), total cholesterol, triglyceride, high-density lipoprotein (HDL) and low-density lipoprotein (LDL) were determined. In addition, the weight of each animal was determined to assess any possible weight gain or loss in the experimental animals (diabetic rats treated with Daonil (group C), the aqueous extract of PB (group D) or the methanolic extract of PB (group E)) compared with control groups (non-diabetic (group A) and non-treated diabetic (group B)). 3. A single dose of 120 mg/kg, i.v., alloxan administered to rats resulted in significant increases in the FPG (P < 0.001) of test animals compared with controls. However, dietary supplementation with PB (6 g/kg extract for 4 weeks administered orally using an intragastric tube) ameliorated the alloxan-induced diabetes in a manner comparable with that of the reference antidiabetic drug glibenclamide. Aqueous and methanolic extracts of PB (6% w/w) elicited 69.2% and 64.4% reductions, respectively, in FPG compared with 70.4% in 0.01 mg/150 g glibenclamide-treated rats. 4. Although animals treated with the aqueous extract of PB gained weight in manner similar to normal controls, animals given the methanolic extract and glibenclamide lost weight in manner similar to non-treated diabetic rats. In addition, high levels of HDL and low LDL were observed in animals treated with the aqueous extract of PB, a pattern similar to that seen in normal controls. Low levels of HDL and high levels of LDL were observed in animals treated with the methanolic extract of PB, a pattern similar to that seen in non-treated diabetic controls. 5. The results of the present study demonstrate that both aqueous and methanolic extracts of fermented seeds of PB exert a hypoglycaemic effect; hence, PB has an antidiabetic property. However, only the aqueous extract of PB ameliorated the loss of bodyweight usually associated with diabetes. Although the aqueous extract has a favourable lipid profile, which is probably an indication of its possible anti-arteriogenic property (hypertension and ischaemic heart diseases being common complications in diabetes mellitus), the methanolic extract shows possible contraindication to ischaemic heart diseases.

Antihyperlipidemic and antiperoxidative effect of Diasulin, a polyherbal formulation in alloxan induced hyperglycemic rats

BACKGROUND

This study was undertaken to investigation the effect of Diasulin, a poly herbal drug composed of ethanolic extract of ten medicinal plants on blood glucose, plasma insulin, tissue lipid profile, and lipidperoxidation in alloxan induced diabetes.

METHODS

Ethanolic extract of Diasulin a, poly herbal drug was administered orally (200 mg/kg body weight) for 30 days. The different doses of Diasulin on blood glucose and plasma insulin in diabetic rats were studied and the levels of lipid peroxides [TBARS, and hydroperoxide] and tissue lipids [cholesterol, triglyceride, phospholipides and free fatty acids] were also estimated in alloxan induced diabetic rats. The effects were compared with glibenclamide.

RESULT

Treatment with Diasulin and glibenclamide resulted in a significant reduction of blood glucose and increase in plasma insulin. Diasulin also resulted in a significant decrease in tissue lipids and lipid peroxide formation. The effect produced by Diasulin was comparable with that of glibenclamide.

CONCLUSION

The decreased lipid peroxides and tissue lipids clearly showed the antihyperlipidemic and antiperoxidative effect of Diasulin apart from its antidiabetic effect.