scholarly journals Energy restriction combined with dipeptidyl peptidase-4 inhibitor exerts neuroprotection in obese male rats

2016 ◽  
Vol 116 (10) ◽  
pp. 1700-1708 ◽  
Author(s):  
Hiranya Pintana ◽  
Pongpan Tanajak ◽  
Wasana Pratchayasakul ◽  
Piangkwan Sa-nguanmoo ◽  
Titikorn Chunchai ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Synaptic Plasticity ◽  
Cognitive Function ◽  
Insulin Sensitivity ◽  
Mitochondrial Function ◽  
Male Rats ◽  
Insulin Resistant ◽  
Hippocampal Synaptic Plasticity ◽  
Brain Insulin ◽  
Brain Mitochondrial Function

AbstractDipeptidyl peptidase-4 (DDP-4) inhibitors and energy restriction (ER) are widely used to treat insulin resistance and type 2 diabetes mellitus. However, the effects of ER or the combination with vildagliptin on brain insulin sensitivity, brain mitochondrial function, hippocampal synaptic plasticity and cognitive function in obese insulin-resistant rats have never been investigated. We hypothesised that ER with DDP-4 inhibitor exerts better efficacy than ER alone in improving cognition in obese insulin-resistant male rats by restoring brain insulin sensitivity, brain mitochondrial function and hippocampal synaptic plasticity. A total of twenty-four male Wistar rats were divided into two groups and fed either a normal diet or a high-fat diet (HFD) for 12 weeks. At week 13, the HFD rats were divided into three subgroups (n 6/subgroup) to receive one of the following treatments: vehicle, ER (60 % of energy received during the previous 12 weeks) or ER plus vildagliptin (3 mg/kg per d, p.o.) for 4 weeks. At the end of the treatment, cognitive function, metabolic parameters, brain insulin sensitivity, hippocampal synaptic plasticity and brain mitochondrial function were determined. We found that HFD-fed rats demonstrated weight gain with peripheral insulin resistance, dyslipidaemia, oxidative stress, brain insulin resistance, impaired brain mitochondrial function and cognitive dysfunction. Although HFD-fed rats treated with ER and ER plus vildagliptin showed restored peripheral insulin sensitivity and improved lipid profiles, only ER plus vildagliptin rats had restored brain insulin sensitivity, brain mitochondrial function, hippocampal synaptic plasticity and cognitive function. These findings suggest that only a combination of ER with DPP-4 inhibitor provides neuroprotective effects in obese insulin-resistant male rats.

scholarly journals Dipeptidyl peptidase 4 inhibitor improves brain insulin sensitivity, but fails to prevent cognitive impairment in orchiectomy obese rats

2015 ◽  
Vol 226 (2) ◽  
pp. M1-M11 ◽  
Author(s):  
Hiranya Pintana ◽  
Wanpitak Pongkan ◽  
Wasana Pratchayasakul ◽  
Nipon Chattipakorn ◽  
Siriporn C Chattipakorn
Keyword(s):  
Insulin Resistance ◽  
Synaptic Plasticity ◽  
Cognitive Function ◽  
Insulin Sensitivity ◽  
Cognitive Decline ◽  
Hippocampal Synaptic Plasticity ◽  
Brain Insulin ◽  
Obese Rats ◽  
Brain Insulin Resistance ◽  
Brain Mitochondrial Function

It is unclear whether the dipeptidyl peptidase 4 (DPP4) inhibitor can counteract brain insulin resistance, brain mitochondrial dysfunction, impairment of hippocampal synaptic plasticity and cognitive decline in testosterone-deprived obese rats. We hypothesized that DPP4 inhibitor vildagliptin improves cognitive function in testosterone-deprived obese rats by restoring brain insulin sensitivity, brain mitochondrial function and hippocampal synaptic plasticity. Thirty male Wistar rats received either a sham-operated (S, n=6) or bilateral orchiectomy (ORX, n=24). ORX rats were divided into two groups and fed with either a normal diet (ND (NDO)) or a high-fat diet (HFO) for 12 weeks. Then, ORX rats in each dietary group were divided into two subgroups (n=6/subgroup) to receive either a vehicle or vildagliptin (3 mg/kg per day, p.o.) for 4 weeks. After treatment, cognitive function, metabolic parameters, brain insulin sensitivity, hippocampal synaptic plasticity and brain mitochondrial function were determined in each rat. We found that HFO rats exhibited peripheral and brain insulin resistance, brain mitochondrial dysfunction, impaired hippocampal synaptic plasticity and cognitive decline. NDO rats did not develop peripheral and brain insulin resistance. However, impaired hippocampal synaptic plasticity and cognitive decline occurred. Vildagliptin significantly improved peripheral insulin sensitivity, restored brain insulin sensitivity and decreased brain mitochondrial reactive oxygen species production in HFO rats. However, vildagliptin did not restore hippocampal synaptic plasticity and cognitive function in both NDO and HFO rats. These findings suggest that vildagliptin could not counteract the impairment of hippocampal synaptic plasticity and cognitive decline in testosterone-deprived subjects, despite its effects on improved peripheral and brain insulin sensitivity as well as brain mitochondrial function.

P2-030: DPP-4 inhibitor improves brain insulin sensitivity, but fails to restore hippocampal synaptic plasticity and cognitive function in testosterone-deprived obese rats

2015 ◽  
Vol 11 (7S_Part_10) ◽  
pp. P492-P493
Author(s):  
Hiranya Pintana ◽  
Wanpitak Pongkan ◽  
Wasana Pratchayasakul ◽  
Nipon Chattipakorn ◽  
Siriporn C. Chattipakorn
Keyword(s):  
Synaptic Plasticity ◽  
Cognitive Function ◽  
Insulin Sensitivity ◽  
Hippocampal Synaptic Plasticity ◽  
Brain Insulin ◽  
Obese Rats

Garlic extract attenuates brain mitochondrial dysfunction and cognitive deficit in obese-insulin resistant rats

2014 ◽  
Vol 39 (12) ◽  
pp. 1373-1379 ◽  
Author(s):  
Hiranya Pintana ◽  
Jirapas Sripetchwandee ◽  
Luerat Supakul ◽  
Nattayaporn Apaijai ◽  
Nipon Chattipakorn ◽  
...  
Keyword(s):  
Body Weight ◽  
Cognitive Function ◽  
Mitochondrial Dysfunction ◽  
Mitochondrial Function ◽  
Visceral Fat ◽  
Cognitive Deficit ◽  
Garlic Extract ◽  
Insulin Resistant ◽  
Mitochondrial Functions ◽  
Brain Mitochondrial Function

Oxidative stress in the obese-insulin resistant condition has been shown to affect cognitive as well as brain mitochondrial functions. Garlic extract has exerted a potent antioxidant effect. However, the effects of garlic extract on the brain of obese-insulin resistant rats have never been investigated. We hypothesized that garlic extract improves cognitive function and brain mitochondrial function in obese-insulin resistant rats induced by long-term high-fat diet (HFD) consumption. Male Wistar rats were fed either normal diet or HFD for 16 weeks (n = 24/group). At week 12, rats in each dietary group received either vehicle or garlic extract (250 and 500 mg·kg–1·day–1) for 28 days. Learning and memory behaviors, metabolic parameters, and brain mitochondrial function were determined at the end of treatment. HFD led to increased body weight, visceral fat, plasma insulin, cholesterol, and malondialdehyde (MDA) levels, indicating the development of insulin resistance. Furthermore, HFD rats had cognitive deficit and brain mitochondrial dysfunction. HFD rats treated with both doses of garlic extract had decreased body weight, visceral fat, plasma cholesterol, and MDA levels. Garlic extract also improved cognitive function and brain mitochondrial function, which were impaired in obese-insulin resistant rats caused by HFD consumption.

scholarly journals Necrostatin-1 Mitigates Cognitive Dysfunction in Prediabetic Rats With no Alteration in Insulin Sensitivity

2020 ◽  
Author(s):  
Ada Admin ◽  
Kewarin Jinawong ◽  
Nattayaporn Apaijai ◽  
Supawit Wongsuchai ◽  
Wasana Pratchayasakul ◽  
...  
Keyword(s):  
Synaptic Plasticity ◽  
Cognitive Function ◽  
Insulin Sensitivity ◽  
Cognitive Decline ◽  
High Fat Diet ◽  
Spine Density ◽  
High Fat ◽  
Dendritic Spine Density ◽  
Microglial Morphology ◽  
Brain Mitochondrial Function

Previous studies show that 12-week of high-fat diet (HFD) consumption caused not only prediabetes, but also cognitive decline and brain pathologies. Recently, necrostatin-1 (nec-1), a necroptosis inhibitor, showed beneficial effects in brain against stroke. However, the comparative effects of nec-1 and metformin on cognition and brain pathologies in prediabetes have not been investigated. We hypothesized that nec-1 and metformin equally attenuated cognitive decline and brain pathologies in prediabetic rats. Rats (n=32) were fed with either normal diet (ND) or high-fat diet (HFD) for 20 weeks. At week 13, ND-fed rats were given a vehicle (n=8) and HFD-fed rats were randomly assigned into 3 subgroups (n=8/subgroup) with vehicle, nec-1 or metformin for 8 weeks. Metabolic parameters, cognitive function, brain insulin receptor function, synaptic plasticity, dendritic spine density, microglial morphology, brain mitochondrial function, Alzheimer’s protein, and cell death were determined.<b> </b>HFD-fed rats exhibited prediabetes, cognitive decline, and brain pathologies. Nec-1 and metformin equally improved cognitive function, synaptic plasticity, dendritic spine density, microglial morphology, brain mitochondrial function, reduced hyperphosphorylated-tau and necroptosis in HFD-fed rats. Interestingly metformin, but not nec-1, improved brain insulin sensitivity in those rats.<b> </b><b> </b>In conclusion, necroptosis inhibition directly improved cognition in prediabetic rats without alteration in insulin sensitivity.

scholarly journals Testosterone deprivation accelerates cardiac dysfunction in obese male rats

2016 ◽  
Vol 229 (3) ◽  
pp. 209-220 ◽  
Author(s):  
Wanpitak Pongkan ◽  
Hiranya Pintana ◽  
Sivaporn Sivasinprasasn ◽  
Thidarat Jaiwongkam ◽  
Siriporn C Chattipakorn ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Mitochondrial Function ◽  
Cardiac Dysfunction ◽  
Left Ventricular ◽  
Normal Diet ◽  
Metabolic Parameters ◽  
Male Rats ◽  
Lv Function ◽  
Insulin Resistant ◽  
Aging Men

Low testosterone level is associated with increased risks of cardiovascular diseases. As obese-insulin-resistant condition could impair cardiac function and that the incidence of obesity is increased in aging men, a condition of testosterone deprivation could aggravate the cardiac dysfunction in obese-insulin-resistant subjects. However, the mechanism underlying this adverse effect is unclear. This study investigated the effects of obesity on metabolic parameters, heart rate variability (HRV), left ventricular (LV) function, and cardiac mitochondrial function in testosterone-deprived rats. Orchiectomized or sham-operated male Wistar rats (n=36per group) were randomly divided into groups and were given either a normal diet (ND, 19.77% of energy fat) or a high-fat diet (HFD, 57.60% of energy fat) for 12weeks. Metabolic parameters, HRV, LV function, and cardiac mitochondrial function were determined at 4, 8, and 12weeks after starting each feeding program. We found that insulin resistance was observed after 8weeks of the consumption of a HFD in both sham (HFS) and orchiectomized (HFO) rats. Neither the ND sham (NDS) group nor ND orchiectomized (NDO) rats developed insulin resistance. The development of depressed HRV, LV contractile dysfunction, and increased cardiac mitochondrial reactive oxygen species production was observed earlier in orchiectomized (NDO and HFO) rats at week 4, whereas HFS rats exhibited these impairments later at week 8. These findings suggest that testosterone deprivation accelerates the impairment of cardiac autonomic regulation and LV function via increased oxidative stress and impaired cardiac mitochondrial function in obese-orchiectomized male rats.

scholarly journals DPP-4 inhibitors improve cognition and brain mitochondrial function of insulin-resistant rats

2013 ◽  
Vol 218 (1) ◽  
pp. 1-11 ◽  
Author(s):  
Hiranya Pintana ◽  
Nattayaporn Apaijai ◽  
Nipon Chattipakorn ◽  
Siriporn C Chattipakorn
Keyword(s):  
Oxidative Stress ◽  
Insulin Resistance ◽  
Mitochondrial Dysfunction ◽  
Mitochondrial Function ◽  
Dipeptidyl Peptidase 4 ◽  
Cognitive Behaviors ◽  
Insulin Resistant ◽  
Stress Levels ◽  
To Receive ◽  
Brain Mitochondrial Function

Recent evidence has demonstrated that insulin resistance is related to the development of type 2 diabetes mellitus. Our previous study found that high-fat diet (HFD) consumption caused not only peripheral and brain insulin resistance but also brain mitochondrial dysfunction and cognitive impairment. Vildagliptin and sitagliptin, dipeptidyl-peptidase-4 inhibitors, are recently developed anti-diabetic drugs. However, the effects of both drugs on cognitive behaviors and brain mitochondrial function in HFD-induced insulin-resistant rats have not yet been investigated. Sixty male Wistar rats were divided into two groups to receive either normal diet or HFD for 12 weeks. Rats in each group were then further divided into three treatment groups to receive either vehicle, vildagliptin (3 mg/kg per day), or sitagliptin (30 mg/kg per day) for 21 days. The cognitive behaviors of the rats were tested using the Morris Water Maze test. Blood samples were collected to determine metabolic parameters and plasma oxidative stress levels. Upon completion of the study, the animals were killed and the brains were removed to investigate brain and hippocampal mitochondrial function as well as to determine oxidative stress levels. We demonstrated that both drugs significantly improved the metabolic parameters and decreased circulating and brain oxidative stress levels in HFD-induced insulin-resistant rats. In addition, both drugs completely prevented brain and hippocampal mitochondrial dysfunction and equally improved the learning behaviors impaired by the HFD. Our findings suggest that the inhibition of dipeptidyl-peptidase-4 enzymes with vildagliptin or sitagliptin in insulin-resistant rats not only increases peripheral insulin sensitivity but also decreases brain dysfunction.

Maternal High-Fat Diet Multigenerationally Impairs Hippocampal Synaptic Plasticity and Memory in Male Rat Offspring

Endocrinology ◽  
2020 ◽  
Vol 162 (1) ◽  
Author(s):  
Cheng Lin ◽  
YanYan Lin ◽  
Ji Luo ◽  
JunRu Yu ◽  
YaNi Cheng ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Synaptic Plasticity ◽  
Cognitive Function ◽  
Learning And Memory ◽  
High Fat Diet ◽  
Maternal Diet ◽  
High Fat ◽  
Hippocampal Synaptic Plasticity ◽  
Insulin Replacement

Abstract As advances are made in the field of developmental origins of health and disease, there is an emphasis on long-term influence of maternal environmental factors on offspring health. Maternal high-fat diet (HFD) consumption has been suggested to exert detrimental effects on cognitive function in offspring, but whether HFD-dependent brain remodeling can be transmitted to the next generations is still unclear. This study tested the hypothesis that HFD consumption during rat pregnancy and lactation multigenerationally influences male offspring hippocampal synaptic plasticity and cognitive function. We observed that hippocampus-dependent learning and memory was impaired in 3 generations from HFD-fed maternal ancestors (referred as F1-F3), as assessed by novel object recognition and Morris water maze tests. Moreover, maternal HFD exposure also affected electrophysiological and ultrastructure measures of hippocampal synaptic plasticity across generations. We observed that intranasal insulin replacement partially rescued hippocampal synaptic plasticity and cognitive deficits in F3 rats, suggesting central insulin resistance may play an important role in maternal diet-induced neuroplasticity impairment. Furthermore, maternal HFD exposure enhanced the palmitoylation of GluA1 critically involved in long-term potentiation induction, while palmitoylation inhibitor 2-bromopalmitate counteracts GluA1 hyperpalmitoylation and partially abolishes the detrimental effects of maternal diet on learning and memory in F3 offspring. Importantly, maternal HFD-dependent GluA1 hyperpalmitoylation was reversed by insulin replacement. Taken together, our data suggest that maternal HFD exposure multigenerationally influences adult male offspring hippocampal synaptic plasticity and cognitive performance, and central insulin resistance may serve as the cross-talk between maternal diet and cognitive impairment across generations.

scholarly journals Necrostatin-1 Mitigates Cognitive Dysfunction in Prediabetic Rats With no Alteration in Insulin Sensitivity

2020 ◽  
Author(s):  
Ada Admin ◽  
Kewarin Jinawong ◽  
Nattayaporn Apaijai ◽  
Supawit Wongsuchai ◽  
Wasana Pratchayasakul ◽  
...  
Keyword(s):  
Synaptic Plasticity ◽  
Cognitive Function ◽  
Insulin Sensitivity ◽  
Cognitive Decline ◽  
High Fat Diet ◽  
Spine Density ◽  
High Fat ◽  
Dendritic Spine Density ◽  
Microglial Morphology ◽  
Brain Mitochondrial Function

Previous studies show that 12-week of high-fat diet (HFD) consumption caused not only prediabetes, but also cognitive decline and brain pathologies. Recently, necrostatin-1 (nec-1), a necroptosis inhibitor, showed beneficial effects in brain against stroke. However, the comparative effects of nec-1 and metformin on cognition and brain pathologies in prediabetes have not been investigated. We hypothesized that nec-1 and metformin equally attenuated cognitive decline and brain pathologies in prediabetic rats. Rats (n=32) were fed with either normal diet (ND) or high-fat diet (HFD) for 20 weeks. At week 13, ND-fed rats were given a vehicle (n=8) and HFD-fed rats were randomly assigned into 3 subgroups (n=8/subgroup) with vehicle, nec-1 or metformin for 8 weeks. Metabolic parameters, cognitive function, brain insulin receptor function, synaptic plasticity, dendritic spine density, microglial morphology, brain mitochondrial function, Alzheimer’s protein, and cell death were determined.<b> </b>HFD-fed rats exhibited prediabetes, cognitive decline, and brain pathologies. Nec-1 and metformin equally improved cognitive function, synaptic plasticity, dendritic spine density, microglial morphology, brain mitochondrial function, reduced hyperphosphorylated-tau and necroptosis in HFD-fed rats. Interestingly metformin, but not nec-1, improved brain insulin sensitivity in those rats.<b> </b><b> </b>In conclusion, necroptosis inhibition directly improved cognition in prediabetic rats without alteration in insulin sensitivity.

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