scholarly journals PPARγ Agonist Improves Neuronal Insulin Receptor Function in Hippocampus and Brain Mitochondria Function in Rats with Insulin Resistance Induced by Long Term High-Fat Diets

Endocrinology ◽  
2012 ◽  
Vol 153 (1) ◽  
pp. 329-338 ◽  
Author(s):  
Noppamas Pipatpiboon ◽  
Wasana Pratchayasakul ◽  
Nipon Chattipakorn ◽  
Siriporn C. Chattipakorn
Keyword(s):  
Insulin Resistance ◽  
Conformational Changes ◽  
Brain Mitochondria ◽  
Normal Diet ◽  
High Fat ◽  
Long Term Depression ◽  
Peripheral Insulin Resistance ◽  
Pparγ Agonist ◽  
Neuronal Insulin Resistance

We previously demonstrated that a high-fat diet (HFD) consumption can cause not only peripheral insulin resistance, but also neuronal insulin resistance. Moreover, the consumption of an HFD has been shown to cause mitochondrial dysfunction in both the skeletal muscle and liver. Rosiglitazone, a peroxizome proliferator-activated receptor-γ ligand, is a drug used to treat type 2 diabetes mellitus. Recent studies suggested that rosiglitazone can improve learning and memory in both human and animal models. However, the effects of rosiglitazone on neuronal insulin resistance and brain mitochondria after the HFD consumption have not yet been investigated. Therefore, we tested the hypothesis that rosiglitazone improves neuronal insulin resistance caused by a HFD via attenuating the dysfunction of neuronal insulin receptors and brain mitochondria. Rosiglitazone (5 mg/kg · d) was given for 14 d to rats that were fed with either a HFD or normal diet for 12 wk. After the 14th week, all animals were euthanized, and their brains were removed and examined for insulin-induced long-term depression, neuronal insulin signaling, and brain mitochondrial function. We found that rosiglitazone significantly improved peripheral insulin resistance and insulin-induced long-term depression and increased neuronal Akt/PKB-ser phosphorylation in response to insulin. Furthermore, rosiglitazone prevented brain mitochondrial conformational changes and attenuated brain mitochondrial swelling, brain mitochondrial membrane potential changes, and brain mitochondrial ROS production. Our data suggest that neuronal insulin resistance and the impairment of brain mitochondria caused by a 12-wk HFD consumption can be reversed by rosiglitazone.

scholarly journals Comparative effects of sex hormone deprivation on the brain of insulin-resistant rats

2019 ◽  
Vol 241 (1) ◽  
pp. 1-15 ◽  
Author(s):  
Jirapas Sripetchwandee ◽  
Hiranya Pintana ◽  
Piangkwan Sa-nguanmoo ◽  
Chiraphat Boonnag ◽  
Wasana Pratchayasakul ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Insulin Resistance ◽  
Cognitive Decline ◽  
Mitochondrial Dysfunction ◽  
Dendritic Spine ◽  
High Fat Diet ◽  
High Fat ◽  
Long Term Depression ◽  
Impaired Insulin

Obese-insulin resistance following chronic high-fat diet consumption led to cognitive decline through several mechanisms. Moreover, sex hormone deprivation, including estrogen and testosterone, could be a causative factor in inducing cognitive decline. However, comparative studies on the effects of hormone deprivation on the brain are still lacking. Adult Wistar rats from both genders were operated upon (sham operations or orchiectomies/ovariectomies) and given a normal diet or high-fat diet for 4, 8 and 12 weeks. Blood was collected to determine the metabolic parameters. At the end of the experiments, rats were decapitated and their brains were collected to determine brain mitochondrial function, brain oxidative stress, hippocampal plasticity, insulin-induced long-term depression, dendritic spine density and cognition. We found that male and female rats fed a high-fat diet developed obese-insulin resistance by week 8 and brain defects via elevated brain oxidative stress, brain mitochondrial dysfunction, impaired insulin-induced long-term depression, hippocampal dysplasticity, reduced dendritic spine density and cognitive decline by week 12. In normal diet-fed rats, estrogen deprivation, not testosterone deprivation, induced obese-insulin resistance, oxidative stress, brain mitochondrial dysfunction, impaired insulin-induced long-term depression, hippocampal dysplasticity and reduced dendritic spine density. In high-fat–diet-fed rats, estrogen deprivation, not testosterone deprivation, accelerated and aggravated obese-insulin resistance and brain defects at week 8. In conclusion, estrogen deprivation aggravates brain dysfunction more than testosterone deprivation through increased oxidative stress, brain mitochondrial dysfunction, impaired insulin-induced long-term depression and dendritic spine reduction. These findings may explain clinical reports which show more severe cognitive decline in aging females than males with obese-insulin resistance.

scholarly journals High-fat diet-induced β-cell proliferation occurs prior to insulin resistance in C57Bl/6J male mice

2015 ◽  
Vol 308 (7) ◽  
pp. E573-E582 ◽  
Author(s):  
Rockann E. Mosser ◽  
Matthew F. Maulis ◽  
Valentine S. Moullé ◽  
Jennifer C. Dunn ◽  
Bethany A. Carboneau ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Cell Proliferation ◽  
High Fat Diet ◽  
Cell Mass ◽  
Chow Diet ◽  
High Fat ◽  
Β Cell ◽  
Peripheral Insulin Resistance ◽  
Insulin Tolerance

Both short- (1 wk) and long-term (2–12 mo) high-fat diet (HFD) studies reveal enhanced β-cell mass due to increased β-cell proliferation. β-Cell proliferation following HFD has been postulated to occur in response to insulin resistance; however, whether HFD can induce β-cell proliferation independent of insulin resistance has been controversial. To examine the kinetics of HFD-induced β-cell proliferation and its correlation with insulin resistance, we placed 8-wk-old male C57Bl/6J mice on HFD for different lengths of time and assayed the following: glucose tolerance, insulin secretion in response to glucose, insulin tolerance, β-cell mass, and β-cell proliferation. We found that β-cell proliferation was significantly increased after only 3 days of HFD feeding, weeks before an increase in β-cell mass or peripheral insulin resistance was detected. These results were confirmed by hyperinsulinemic euglycemic clamps and measurements of α-hydroxybutyrate, a plasma biomarker of insulin resistance in humans. An increase in expression of key islet-proliferative genes was found in isolated islets from 1-wk HFD-fed mice compared with chow diet (CD)-fed mice. These data indicate that short-term HFD feeding enhances β-cell proliferation before insulin resistance becomes apparent.

scholarly journals One-Year High Fat Diet Affects Muscle-But Not Brain Mitochondria

2015 ◽  
Vol 35 (6) ◽  
pp. 943-950 ◽  
Author(s):  
Tenna Jørgensen ◽  
Niels Grunnet ◽  
Bjørn Quistorff
Keyword(s):  
Insulin Resistance ◽  
Skeletal Muscle ◽  
Brain Mitochondria ◽  
High Fat ◽  
Metabolic Disturbances ◽  
Palmitoyl Carnitine ◽  
Skeletal Muscle Mitochondria ◽  
One Year ◽  
The Brain

It is well known that few weeks of high fat (HF) diet may induce metabolic disturbances and mitochondrial dysfunction in skeletal muscle. However, little is known about the effects of long-term HF exposure and effects on brain mitochondria are unknown. Wistar rats were fed either chow (13E% fat) or HF diet (60E% fat) for 1 year. The HF animals developed obesity, dyslipidemia, insulin resistance, and dysfunction of isolated skeletal muscle mitochondria: state 3 and state 4 were 30% to 50% increased ( P < 0.058) with palmitoyl carnitine (PC), while there was no effect with pyruvate as substrate. Adding also succinate in state 3 resulted in a higher substrate control ratio (SCR) with PC, but a lower SCR with pyruvate ( P < 0.05). The P/O2 ratio was lower with PC ( P < 0.004). However, similar tests on isolated brain mitochondria from the same animal showed no changes with the substrates relevant for brain (pyruvate and 3-hydroxybutyrate). Thus, long-term HF diet was associated with obesity, dyslipidemia, insulin resistance, and significantly altered mitochondrial function in skeletal muscle. Yet, brain mitochondria were unaffected. We suggest that the relative isolation of the brain due to the blood-brain barrier may play a role in this strikingly different phenotype of mitochondria from the two tissues of the same animal.

High Fat Diet Mediates Amyloid-β Cleaving Enzyme 1 Phosphorylation and SUMOylation, Enhancing Cognitive Impairment in APP/PS1 Mice

2021 ◽  
pp. 1-14
Author(s):  
Jian Bao ◽  
Zheng Liang ◽  
Xiaokang Gong ◽  
Jing Yu ◽  
Yifan Xiao ◽  
...  
Keyword(s):  
Cognitive Performance ◽  
High Fat Diet ◽  
Amyloid Β ◽  
Normal Diet ◽  
Standard Diet ◽  
High Fat ◽  
Augmented Learning ◽  
Biochemical Analyses ◽  
Modifiable Lifestyle Factors

Background: Alzheimer’s disease (AD) is the most common form of dementia in older adults and extracellular accumulation of amyloid-β (Aβ) is one of the two characterized pathologies of AD. Obesity is significantly associated with AD developing factors. Several studies have reported that high fat diet (HFD) influenced Aβ accumulation and cognitive performance during AD pathology. However, the underlying neurobiological mechanisms have not yet been elucidated. Objective: The objective of this study was to explore the underlying neurobiological mechanisms of HFD influenced Aβ accumulation and cognitive performance during AD pathology. Methods: 2.5-month-old male APP/PS1 mice were randomly separated into two groups: 1) the normal diet (ND) group, fed a standard diet (10 kcal%fat); and 2) the HFD group, fed a high fat diet (40 kcal%fat, D12492; Research Diets). After 4 months of HFD or ND feeding, mice in the two groups were subjected for further ethological, morphological, and biochemical analyses. Results: A long-term HFD diet significantly increased perirenal fat and impaired dendritic integrity and aggravated neurodegeneration, and augmented learning and memory deficits in APP/PS1 mice. Furthermore, the HFD increased beta amyloid cleaving enzyme 1 (BACE1) dephosphorylation and SUMOylation, resulting in enhanced enzyme activity and stability, which exacerbated the deposition of amyloid plaques. Conclusion: Our study demonstrates that long-term HFD consumption aggravates amyloid-β accumulation and cognitive impairments, and that modifiable lifestyle factors, such as obesity, can induce BACE1 post-modifications which may contribute to AD pathogenesis.

scholarly journals Prebiotic prevents impaired kidney and renal Oat3 functions in obese rats

2018 ◽  
Vol 237 (1) ◽  
pp. 29-42 ◽  
Author(s):  
Keerati Wanchai ◽  
Sakawdaurn Yasom ◽  
Wannipa Tunapong ◽  
Titikorn Chunchai ◽  
Parameth Thiennimitr ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Renal Function ◽  
High Fat Diet ◽  
Organic Anion ◽  
Normal Diet ◽  
Organic Anion Transporter ◽  
High Fat ◽  
Insulin Resistant ◽  
Beneficial Effects ◽  
Anion Transporter

Obesity is health issue worldwide, which can lead to kidney dysfunction. Prebiotics are non-digestible foods that have beneficial effects on health. This study aimed to investigate the effects of xylooligosaccharide (XOS) on renal function, renal organic anion transporter 3 (Oat3) and the mechanisms involved. High-fat diet was provided for 12 weeks in male Wistar rats. After that, the rats were divided into normal diet (ND); normal diet treated with XOS (NDX); high-fat diet (HF) and high-fat diet treated with XOS (HFX). XOS was given daily at a dose of 1000 mg for 12 weeks. At week 24, HF rats showed a significant increase in obesity and insulin resistance associated with podocyte injury, increased microalbuminuria, decreased creatinine clearance and impaired Oat3 function. These alterations were improved by XOS supplementation. Renal MDA level and the expression of AT1R, NOX4, p67phox, 4-HNE, phosphorylated PKCα and ERK1/2 were significantly decreased after XOS treatment. In addition, Nrf2-Keap1 pathway, SOD2 and GCLC expression as well as renal apoptosis were also significantly reduced by XOS. These data suggest that XOS could indirectly restore renal function and Oat3 function via the reduction of oxidative stress and apoptosis through the modulating of AT1R-PKCα-NOXs activation in obese insulin-resistant rats. These attenuations were instigated by the improvement of obesity, hyperlipidemia and insulin resistance.

scholarly journals Effects of Maternal Resveratrol on Maternal High-Fat Diet/Obesity with or without Postnatal High-Fat Diet

2020 ◽  
Vol 21 (10) ◽  
pp. 3428 ◽  
Author(s):  
Mei-Hsin Hsu ◽  
Jiunn-Ming Sheen ◽  
I-Chun Lin ◽  
Hong-Ren Yu ◽  
Mao-Meng Tiao ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Blood Pressure ◽  
Cognitive Impairment ◽  
Adult Male ◽  
High Fat Diet ◽  
Dorsal Hippocampus ◽  
Fetal Brain ◽  
Male Offspring ◽  
High Fat ◽  
Peripheral Insulin Resistance

To examine the effects of maternal resveratrol in rats borne to dams with gestational high-fat diet (HFD)/obesity with or without postnatal high-fat diet. We first tested the effects of maternal resveratrol intake on placenta and male fetus brain in rats borne to dams with gestational HFD/obesity. Then, we assessed the possible priming effect of a subsequent insult, male offspring were weaned onto either a rat chow or a HFD. Spatial learning and memory were assessed by Morris water maze test. Blood pressure and peripheral insulin resistance were examined. Maternal HFD/obesity decreased adiponectin, phosphorylation alpha serine/threonine-protein kinase (pAKT), sirtuin 1 (SIRT1), and brain-derived neurotrophic factor (BDNF) in rat placenta, male fetal brain, and adult male offspring dorsal hippocampus. Maternal resveratrol treatment restored adiponectin, pAKT, and BDNF in fetal brain. It also reduced body weight, peripheral insulin resistance, increased blood pressure, and alleviated cognitive impairment in adult male offspring with combined maternal HFD and postnatal HFD. Maternal resveratrol treatment restored hippocampal pAKT and BDNF in rats with combined maternal HFD and postnatal HFD in adult male offspring dorsal hippocampus. Maternal resveratrol intake protects the fetal brain in the context of maternal HFD/obesity. It effectively reduced the synergistic effects of maternal HFD/obesity and postnatal HFD on metabolic disturbances and cognitive impairment in adult male offspring. Our data suggest that maternal resveratrol intake may serve as an effective therapeutic strategy in the context of maternal HFD/obesity.

scholarly journals Long-term oral administration of osteocalcin induces insulin resistance in male mice fed a high-fat, high-sucrose diet

2016 ◽  
Vol 310 (8) ◽  
pp. E662-E675 ◽  
Author(s):  
Yu Yasutake ◽  
Akiko Mizokami ◽  
Tomoyo Kawakubo-Yasukochi ◽  
Sakura Chishaki ◽  
Ichiro Takahashi ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Oral Administration ◽  
Pancreatic Β Cell ◽  
Male Mice ◽  
High Fat ◽  
Β Cell ◽  
Sucrose Diet ◽  
High Sucrose Diet ◽  
High Sucrose

Uncarboxylated osteocalcin (GluOC), a bone-derived hormone, regulates energy metabolism by stimulating insulin secretion, pancreatic β-cell proliferation, and adiponectin expression in adipocytes. Previously, we showed that long-term intermittent or daily oral administration of GluOC reduced the fasting blood glucose level, improved glucose tolerance, and increased the fasting serum insulin concentration as well as pancreatic β-cell area in female mice fed a normal or high-fat, high-sucrose diet. We have now performed similar experiments with male mice and found that such GluOC administration induced glucose intolerance, insulin resistance, and adipocyte hypertrophy in those fed a high-fat, high-sucrose diet. In addition, GluOC increased the circulating concentration of testosterone and reduced that of adiponectin in such mice. These phenotypes were not observed in male mice fed a high-fat, high-sucrose diet after orchidectomy, but they were apparent in orchidectomized male mice or intact female mice that were fed such a diet and subjected to continuous testosterone supplementation. Our results thus reveal a sex difference in the effects of GluOC on glucose homeostasis. Given that oral administration of GluOC has been considered a potentially safe and convenient option for the treatment or prevention of metabolic disorders, this sex difference will need to be taken into account in further investigations.

scholarly journals Long-Term Consumption of Platycodi Radix Ameliorates Obesity and Insulin Resistance via the Activation of AMPK Pathways

2012 ◽  
Vol 2012 ◽  
pp. 1-11 ◽  
Author(s):  
Chae Eun Lee ◽  
Haeng Jeon Hur ◽  
Jin-Taek Hwang ◽  
Mi Jeong Sung ◽  
Hye Jeong Yang ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
High Fat Diet ◽  
Adipocyte Differentiation ◽  
Cultured Cells ◽  
C2c12 Myotubes ◽  
Obese Mice ◽  
High Fat ◽  
Platycodi Radix ◽  
Chemotactic Protein

This study was designed to evaluate the effects and mechanism of Platycodi radix, having white balloon flower (Platycodon grandiflorum for. albiflorum (Honda) H. Hara) on obesity and insulin resistance. The extracts of Platycodi radix with white balloon flower were tested in cultured cells and administered into mice on a high-fat diet. The Platycodi radix activated the AMPK/ACC phosphorylation in C2C12 myotubes and also suppressed adipocyte differentiation in 3T3-L1 cells. In experimental animal, it suppressed the weight gain of obese mice and ameliorated obesity-induced insulin resistance. It also reduced the elevated circulating mediators, including triglyceride (TG), T-CHO, leptin, resistin, and monocyte chemotactic protein (MCP)-1 in obesity. As shown in C2C12 myotubes, the administration of Platycodi radix extracts also recovered the AMPK/ACC phosphorylation in the muscle of obese mice. These results suggest that Platycodi radix with white balloon flower ameliorates obesity and insulin resistance in obese mice via the activation of AMPK/ACC pathways and reductions of adipocyte differentiation.

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