Tri-modal In vivo Imaging of Pancreatic Islets Transplanted Subcutaneously in Mice.

Purpose: Transplantation of pancreatic islets (PIs) is a promising therapeutic approach for type 1 diabetes. The main obstacle for this strategy is that the outcome of islet engraftment depends on the engraftment site. It was our aim to develop a strategy for using non-invasive imaging techniques to assess the location and fate of transplanted PIs longitudinally in vivo.

Improved Labeling of Pancreatic Islets Using Cationic Magnetoliposomes.

Pancreatic islets (PIs) transplantation is an alternative approach for the treatment of severe forms of type 1 diabetes (T1D). To monitor the success of transplantation, it is desirable to follow the location of engrafted PIs non-invasively. In vivo magnetic resonance imaging (MRI) of transplanted PIs is a feasible cell tracking method; however, this requires labeling with a suitable contrast agent prior to transplantation.

Comparison of different compressed sensing algorithms for low SNR F MRI applications-Imaging of transplanted pancreatic islets and cells labeled with perfluorocarbons.

Transplantation of pancreatic islets is a possible treatment option for patients suffering from Type I diabetes. In vivo imaging of transplanted islets is important for assessment of the transplantation site and islet distribution. Thanks to its high specificity, the absence of intrinsic background signal in tissue and its potential for quantification, F MRI is a promising technique for monitoring the fate of transplanted islets in vivo.

In vivo and ex vivo 19-fluorine magnetic resonance imaging and spectroscopy of beta-cells and pancreatic islets using GLUT-2 specific contrast agents.

The assessment of the β-cell mass in experimental models of diabetes and ultimately in patients is a hallmark to understand the relationship between reduced β-cell mass/function and the onset of diabetes. It has been shown before that the GLUT-2 transporter is highly expressed in both β-cells and hepatocytes and that D-mannoheptulose (DMH) has high uptake specificity for the GLUT-2 transporter. As 19-fluorine MRI has emerged as a new alternative method for MRI cell tracking because it provides potential non-invasive localization and quantification of labeled cells, the purpose of this project is to validate β-cell and pancreatic islet imaging by using fluorinated, GLUT-2 targeting mannoheptulose derivatives ( FMH) both in vivo and ex vivo.

Effects of vitamin D on insulin secretion and glucose transporter GLUT2 under static magnetic field in rat.

The present study investigated the effects of vitamin D supplementation on insulin secretion and glucose transporter following static magnetic field (SMF) exposure in rat. Wistar male rats were divided into the following groups: control, SMF-exposed rat (128 mT; 1 h/day for 5 days), vitamin D-treated rats (1600 IU/100 g, received by gavage for five consecutive days), and co-exposed rats (the last day and after exposure rats received a single dose of vitamin D per os). Our results showed that exposure to SMF induced an increase in plasma glucose level and a decrease in plasma insulin concentration.

Vitamin D supplementation ameliorates hypoinsulinemia and hyperglycemia in static magnetic field-exposed rat.

The purpose of this study is to evaluate the effects of vitamin D supplementation on glucose and lipid metabolism in static magnetic field (SMF)-exposed rats. Rats exposed to SMF (128 mT; 1 h/day) during 5 consecutive days showed an increase in plasma glucose level and a decrease in plasma insulin concentration. By contrast, the same treatment failed to alter body weight and plasmatic total cholesterol, high-density lipoprotein (HDL)-cholesterol, low-density lipoprotein (LDL)-cholesterol, and triglyceride levels.

Vitamin E prevents glucose metabolism alterations induced by static magnetic field in rats.

In the present study, we investigate the effects of a possible protective role of vitamin E (vit E) or selenium (Se) on glucose metabolism disruption induced by static magnetic field (SMF) in rats. Rats have been exposed to SMF (128 mT, 1 h/day during 5 days). Our results showed that SMF failed to alter body weight and relative liver weight.

Uptake and efflux of 3-O-methyl-D-glucose in rat parotid cells.

In the framework of recent investigations on the regulation of D-glucose production by salivary glands, the aim of the present study was to compare the uptake of 3-O-[C]methyl-D-glucose by rat parotid cells over a 6-min incubation period at 37°C to its efflux from prelabelled parotid cells, also incubated for 6 min at 37°C. It was first assessed that the intracellular HOH water space, whether expressed in absolute terms or relative to the total HOH distribution space, is not significantly different between parotid cells obtained from either control rats or streptozotocin-induced diabetic rats. In the control rats, the uptake of 3-O-[C]methyl-D-glucose corresponded, following correction for extracellular contamination, to a mean distribution space of 0.

Protective action of seed extracts against the deleterious effect of streptozotocin on both glucose-stimulated insulin release from rat pancreatic islets and glucose homeostasis.

extracts improve glucose homeostasis in alloxan- or streptozotocin (STZ)-induced diabetic rats. Little is known, however, regarding the protective effect of these extracts against the β-cytotoxic action of STZ. In the present study, an HO-methanol extract was found to suppress the inhibition of glucose-stimulated insulin secretion by STZ in rat-isolated pancreatic islets.

Insulinotropic action of Citrullus colocynthis seed extracts in rat pancreatic islets.

The present study aimed to investigate the direct in vitro effects of several distinct Citrullus colocynthis seed extracts on glucose-stimulated insulin release from pancreatic islets isolated from rats. Six extracts were tested, a crude aqueous, defatted aqueous, ethyl acetate, H2O-methanol and n-butanol extract and an extract containing a major component (fraction A) identified by gel chromatography in the ethyl acetate, n-butanol and H2O-methanol extracts. Under selected experimental conditions, the majority of extracts exhibited a positive insulinotropic action, at least when tested in the presence of 8.

The metabolic syndrome of fructose-fed rats: effects of long-chain polyunsaturated ω3 and ω6 fatty acids. V. Post-mortem findings.

The present study deals with the possible effects of dietary ω3 and ω6 fatty acids upon the metabolic syndrome found in rats exposed for 8 weeks to a diet containing 64% (w/w) D-fructose instead of starch. Fructose-fed rats were found to display a modest increase in plasma albumin and protein concentration and more pronounced increases in plasma urea, creatinine, phospholipids, triglycerides and cholesterol concentrations, glycated hemoglobin concentration and liver contents of cholesterol, triglycerides and phospholipids. The plasma concentrations of HDL-cholesterol, calcium and iron were decreased, however, in the fructose-fed rats.

Glucose transport by acinar cells in rat parotid glands.

Background/aims: Salivary glucose is often considered as being from glandular origin. Little information is available, however, on the possible role of glucose transporters in the secretion of the hexose by salivary glands. The major aim of the present study was to investigate the expression and localization of several distinct glucose transporters in acinar cells of rat parotid glands.

Perturbation of glycerol metabolism in hepatocytes from n3-PUFA-depleted rats.

Second generation n3-PUFA-depleted rats represent a good animal model of metabolic syndrome as they display several features of the disease such as liver steatosis, visceral obesity and insulin resistance. The goal of our study was to investigate the influence of n3-PUFA deficiency on hepatic glycerol metabolism. Aquaglyceroporin 9 (AQP9) allows hepatic glycerol transport and consequently contributes to neoglucogenesis.

A new role for aquaporin 7 in insulin secretion.

Unlabelled: BACGROUNS/AIMS: Several insulinotropic agents were recently reported to cause β-cell swelling. The possible participation of AQP7 to water transport was investigated in AQP7(+/+) or AQP7(-/-) mice.

Methods: Aquaporin expression, insulin secretion, cell swelling and electrical activity were investigated in pancreatic islets.

Intermittent fasting modulation of the diabetic syndrome in streptozotocin-injected rats.

This study investigates the effects of intermittent overnight fasting in streptozotocin-induced diabetic rats (STZ rats). Over 30 days, groups of 5-6 control or STZ rats were allowed free food access, starved overnight, or exposed to a restricted food supply comparable to that ingested by the intermittently fasting animals. Intermittent fasting improved glucose tolerance, increased plasma insulin, and lowered Homeostatis Model Assessment index.

Glycerol metabolism alteration in adipocytes from n3-PUFA-depleted rats, an animal model for metabolic syndrome.

Aquaglyceroporin 7 (AQP7) is a glycerol transporter expressed in adipocytes. Its expression has been shown to be modulated in obesity. Metabolic syndrome is characterized by abdominal obesity, insulin resistance, dyslipidemia, and hypertension.

(19)F-heptuloses as tools for the non-invasive imaging of GLUT2-expressing cells.

Suitable analogs of d-mannoheptulose are currently considered as possible tools for the non-invasive imaging of pancreatic islet insulin-producing cells. Here, we examined whether (19)F-heptuloses could be used for non-invasive imaging of GLUT2-expressing cells. After 20 min incubation, the uptake of (19)F-heptuloses (25 mM) by rat hepatocytes, as assessed by (19)F NMR spectroscopy, ranged from 0.

Does NAD(P)H oxidase-derived H2O2 participate in hypotonicity-induced insulin release by activating VRAC in β-cells?

NAD(P)H oxidase (NOX)-derived H(2)O(2) was recently proposed to act, in several cells, as the signal mediating the activation of volume-regulated anion channels (VRAC) under a variety of physiological conditions. The present study aims at investigating whether a similar situation prevails in insulin-secreting BRIN-BD11 and rat β-cells. Exogenous H(2)O(2) (100 to 200 μM) at basal glucose concentration (1.

Dietary sardine protein lowers insulin resistance, leptin and TNF-α and beneficially affects adipose tissue oxidative stress in rats with fructose-induced metabolic syndrome.

The present study aims at exploring the effects of sardine protein on insulin resistance, plasma lipid profile, as well as oxidative and inflammatory status in rats with fructose-induced metabolic syndrome. Rats were fed sardine protein (S) or casein (C) diets supplemented or not with high-fructose (HF) for 2 months. Rats fed the HF diets had greater body weight and adiposity and lower food intake as compared to control rats.

The metabolic syndrome of fructose-fed rats: effects of long-chain polyunsaturated ω3 and ω6 fatty acids. IV. D-glucose metabolism by isolated pancreatic islets.

The major aim of the present study was to search for changes of D-glucose metabolism in isolated pancreatic islets possibly involved in the alteration of their secretory response to the hexose, as observed when comparing rats exposed for 8 weeks to diets containing either starch and sunflower oil or fructose and sunflower oil, as well as rats exposed to diets containing fructose, sunflower oil and either salmon oil or safflower oil. The substitution of starch by fructose in the diet affected unfavourably D-glucose phosphorylation by the isolated islets. In the fructose-fed rats, there was a close parallelism between D-[5-³H]glucose utilization and the dietary ω3/ω6 fatty acid ratio.

The metabolic syndrome of fructose-fed rats: effects of long-chain polyunsaturated ω3 and ω6 fatty acids. III. Secretory behaviour of isolated pancreatic islets.

In the present study, rats were exposed from the 8th week after birth and for the ensuing 8 weeks to diets containing either starch or fructose (64% w/w) and sunflower oil (5%). Two further groups of rats were exposed to the fructose-containing diet with substitution of part (1.6%) of the sunflower diet by an equal amount of either salmon oil rich in long-chain polyunsaturated ω3 fatty acids or safflower oil reach in long-chain polyunsaturated ω6 fatty acids.

The metabolic syndrome of fructose-fed rats: effects of long-chain polyunsaturated ω3 and ω6 fatty acids. II. Time course of changes in food intake, body weight, plasma glucose and insulin concentrations and insulin resistance.

The time course for changes in food intake, body weight, plasma glucose and insulin concentrations and HOMA index was monitored over a period of 8 weeks in rats exposed from the 8th week after birth to diets containing either starch or fructose and sunflower oil. In two further groups of rats exposed to the fructose-rich diet part of the sunflower oil was substituted by either salmon oil rich in long-chain polyunsaturated ω3 fatty acids or safflower oil rich in long-chain polyunsaturated ω6 fatty acids. Despite lower food intake, the gain in body weight was higher in fructose-fed rats than in starch-fed rats.

The metabolic syndrome of fructose-fed rats: effects of long-chain polyunsaturated ω3 and ω6 fatty acids. I. Intraperitoneal glucose tolerance test.

The present series of experiments aim mainly at investigating the possible influence of changes in the com-position of dietary lipids (sunflower oil, salmon oil, safflower oil) upon the metabolic syndrome found in rats exposed to a fructose-rich diet. For purpose of comparison, a control group of rats received the sunflower oil diet with substitution of fructose by starch. An intraperitoneal glucose tolerance test, performed after overnight starvation fifty days after the start of the experiments at the 6th week after birth, indicated, as expected, impaired tolerance to glucose and deterioration of insulin sensitivity (HOMA index), without changes in the insulinogenic index, when comparing the fructose-fed rats to the starch-fed rats both exposed to the sunflower oil diet.

Intermittent fasting modulation of the diabetic syndrome in sand rats. III. Post-mortem investigations.

The present report concerns several post-mortem variables examined in sand rats that were either maintained on a vegetal diet (control animals) or exposed first during a 20-day transition period to a mixed diet consisting of a fixed amount of a hypercaloric food and decreasing amounts of the vegetal food and then to a 30-day experimental period of exposure to the hypercaloric food. During the latter period, all animals were either given free access to food or fasting daily for 15 h, i.e.

Fatty acid pattern of pancreatic islet lipids in Goto-Kakizaki rats.

Perturbations of fatty acid content and pattern were recently documented in epididymal and parametrial lipids, as well as plasma, liver, spleen, and brain phospholipids and triglycerides of Goto-Kakizaki rats (GK). This study extends such an investigation to pancreatic islets from both control and GK rats. Groups of 5,500-14,560 islets were obtained from either control or GK rats (n = 3 in each case) and examined for their lipid fatty acid content.