Effects Of High-fat Diet Consumption Research Articles

7216 Absence Of Weight Gain In C57Bl/67 Female Mice On A High-Fat Diet Protects The Skeleton From Bone Loss

Abstract Disclosure: C. McAndrews: None. C. Chlebek: None. S. Costa: None. C.J. Rosen: None. Background: Obesity is associated with both systemic metabolic changes that increase the risk of comorbidities and reduced bone quality that increases the risk of fracture. The effects of high-fat diet consumption have been well studied in preclinical models where high-fat diet-feeding induces obesity, but there have been no studies to investigate the effects of high-fat diet-feeding in animals that do not become obese. Therefore, we characterized components of systemic metabolism and bone mineral content in non-obese C57Bl/6J mice that were fed a high-fat diet. Methods: Female C57Bl/6J mice aged 8 weeks received either a high-fat (60% kcal fat, n = 31) or control (10% kcal fat, n = 17) diet for 12 weeks. Body composition, areal bone mineral density (BMD) and bone mineral composition (BMC) were assessed after the feeding period using dual energy x-ray absorptiometry (Faxitron UltraFocus-DXA). Glucose (GTT) and insulin (ITT) tolerance testing were performed at the conclusion of the study. Changes in body weight were calculated as the difference between baseline and experiment end. High-fat diet-fed animals were classified as obese (HFD-O, n = 24) if they weighed more than 25 g or had greater than 25% body fat as evaluated via DXA, and were otherwise considered non-obese (HFD-NO, n = 7). In a small subset of animals, subcutaneous inguinal fat pads were harvested and weighed (n=5-7/group). Differences between groups were assessed with one-way ANOVAs and Tukey post-hoc analyses. Results: HFD-O mice weighed more than HFD-NO and control animals, whereas the body weights of HFD-NO mice were not significantly different from control (p < 0.001). Fat percent was increased in HFD-O mice compared to HFD-NO and control animals (p < 0.001). Subcutaneous inguinal fat mass was increased in both HFD-O and HFD-NO mice compared to control (p < 0.001). Fasting blood glucose did not significantly differ between groups. Glucose tolerance was worsened in both HFD-O and HFD-NO mice compared to control (p < 0.001), but there were no significant differences in insulin tolerance between groups. BMD was decreased in HFD-O mice compared to HFD-NO and control animals (p < 0.001). DISCUSSION: The consumption of a high-fat diet in mice induces deleterious metabolic changes irrespective of weight gain. However, high-fat diet-induced bone loss does not occur in the absence of weight gain. These findings suggest that certain adipokines derived from larger adipose depots may drive high-fat diet-induced bone loss and warrant further investigation. Acknowledgements: This work was supported by the 2023 Endocrine Society Research Experiences for Graduate and Medical Students (REGMS) Program. Presentation: 6/1/2024

Increased Mortality Risk at Septic Condition in Inflammatory Skin Disorders and the Effect of High-Fat Diet Consumption.

In recent years, attention has increasingly focused on various infectious diseases. Although some fatalities are directly attributed to the causative virus, many result from complications and reactive inflammation. Patients with comorbidities are at a higher risk of mortality. Refractory skin conditions such as atopic dermatitis, psoriasis, and epidermolysis bullosa, known for an elevated risk of sepsis, partly owe this to compromised surface barrier function. However, the detailed mechanisms underlying this phenomenon remain elusive. Conversely, although the detrimental effects of a high-fat diet on health, including the onset of metabolic syndrome, are widely recognized, the association between diet and susceptibility to sepsis has not been extensively explored. In this study, we examined the potential causes and pathogenesis of increased sepsis susceptibility in inflammatory skin diseases using a mouse dermatitis model: keratin 14-driven caspase-1 is overexpressed (KCASP1Tg) in mice on a high-fat diet. Our findings reveal that heightened mortality in the dermatitis mouse model is caused by the inflamed immune system due to the chronic inflammatory state of the local skin, and administration of LPS causes a rapid increase in inflammatory cytokine levels in the spleen. Intake of a high-fat diet exacerbates these cytokine levels. Interestingly, we also observed a reduced expression of Toll-like receptor 4 (TLR4) in monocytes from KCASP1Tg mice, potentially predisposing these animals to heightened infection risks and associated complications. Histological analysis showed a clear decrease in T and B cells in the spleen of KCASP1Tg mice fed a high-fat diet. Thickening of the alveolar wall, inflammatory cell infiltration, and alveolar hemorrhage were more prominent in the lungs of KCASP1Tg and KCASP1Tg with fat mice. We postulate that the chronic, non-infectious inflammation induces a negative feedback loop within the inflammatory cascade, and the suppressed expression of TLR4 renders the mice more susceptible to infections. Therefore, it is imperative for individuals with chronic skin inflammation to closely monitor disease progression upon infection and seek timely and appropriate treatment. Additionally, chronic inflammation of adipose tissue, induced by high-fat food intake, combined with dermatitis inflammation, may exacerbate infections, necessitating a review of dietary habits.

Açai pulp improves cognition and insulin sensitivity in obese mice

ABSTRACT Scope Obesity and insulin resistance constitute risk factors for the development of tauopathies and other neurodegenerative diseases. (Poly)phenol compounds are under study for its role in protecting effects against neural injuries and degeneration. Here, we investigated the effect of Amazonian açai pulp (AP) intake in the prevention of memory and cognitive impairment resulting from a high-fat diet intake in mice. Methods and results Obesity and insulin resistance was induced with a high-fat diet and supplemented with 2% AP to investigate peripheral insulin resistance, recognition memory and tau protein stability via AKT/GSK3-β signaling pathway. The consumption of AP for 70 days improved peripheral insulin sensitivity and phosphorylation of AKT/GSK3-β in mice hippocampi. The animals fed high-fat diets supplemented with AP showed better performance in the novel object recognition test (NOR) in comparison to the H group. Catalase activity and reduced glutathione (GSH) values were improved in the treated mice. Conclusions These results suggest that the supplementation of AP can attenuate the effects of high-fat diet consumption in peripheral insulin resistance and improve cognitive behavior.

Dysregulation of nuclear factor erythroid 2-related factor 2 signaling and activation of fibrogenic pathways in hearts of high fat diet-fed rats.

High fat diet (HFD)-induced obesity adversely affects cardiac outcomes; however the effect of HFD consumption on myocardial remodeling and the underlying mechanisms are still elusive. This study aimed to examine the histological and molecular changes in cardiac tissue of HFD-fed rats. Eight-week old male Wistar rats were fed either HFD or normal chow diet for 16weeks and then assessed for changes in metabolic and cardiac homeostasis (n=10 each group). 16weeks on HFD resulted in obesity, dyslipidemia and altered glucose tolerance but no hypertension. Histological examination of Masson's trichrome stained-cardiac sections revealed massive fibrotic changes, while immunoblotting analysis showed higher expressions of collagens I and III, and fibronectin in cardiac tissue of HFD-fed rats. The expressions of transforming growth factor beta1 and the phosphorylation of its downstream target, Smad3, were significantly increased in cardiac tissue of HFD-fed rats. Activation of endothelial-mesenchymal transition was promoted in hearts of HFD-fed rats, as evidenced by down-regulation of platelet endothelial cell adhesion molecule-1, while upregulation of α-smooth muscle actin and vimentin. Consumption of HFD induced dysregulation of AMP-activated protein kinase/glycogen synthase kinase-3 beta signaling in cardiac tissue of rats. This was coupled with down-regulation of nuclear factor erythroid-2-related factor 2 (Nrf2) and its downstream targets in cardiac tissue of HFD-fed rats, as well as enhanced the oxidative stress and inflammatory burden. These results demonstrate that moderate-term consumption of HFD can enhance oxidative stress, induce inflammation, and activate the fibrogenic pathways in cardiac tissue of rats which stimulate fibrotic remodeling. Our findings may implicate the dysregulation of Nrf2 signaling as a putative mechanism for this effect.

Maternal high-fat diet results in cognitive impairment and hippocampal gene expression changes in rat offspring

Consumption of a high-fat diet has long been known to increase risk for obesity, diabetes, and the metabolic syndrome. Further evidence strongly suggests that these same metabolic disorders are associated with an increased risk of cognitive impairment later in life. Now faced with an expanding global burden of obesity and increasing prevalence of dementia due to an aging population, understanding the effects of high-fat diet consumption on cognition is of increasingly critical importance. Further, the developmental origins of many adult onset neuropsychiatric disorders have become increasingly clear, indicating a need to investigate effects of various risk factors, including diet, across the lifespan. Here, we use a rat model to assess the effects of maternal diet during pregnancy and lactation on cognition and hippocampal gene expression of offspring. Behaviorally, adult male offspring of high-fat fed dams had impaired object recognition memory and impaired spatial memory compared to offspring of chow-fed dams. In hippocampus, we found decreased expression of Insr, Lepr, and Slc2a1 (GLUT1) among offspring of high-fat fed dams at postnatal day 21. The decreased expression of Insr and Lepr persisted at postnatal day 150. Together, these data provide additional evidence to suggest that maternal exposure to high-fat diet during pregnancy and lactation can have lasting effects on the brain, behavior, and cognition on adult offspring.

Moderate Physical Training Ameliorates Cardiovascular Dysfunction Induced by High Fat Diet After Cessation of Training in Adult Rats

We aimed to test whether moderate physical training can induce long-lasting protection against cardiovascular risk factors induced by high fat diet (HFD) intake, even after cessation of training. 90-days-old Wistar rats were submitted to a sedentary lifestyle or moderate physical training, three times a week, for 30 days. Following this, at 120 days-of age, sedentary and trained rats received a hypercaloric diet (HFD) or a commercial diet normal fat diet (NFD) for 30 days. Body weight (BW) and food intake were evaluated weekly. At 150 days-of age, hemodynamic measures (systolic, diastolic, mean blood pressure, pulse pressure, pulse interval and heart rate) were made via an indwelling femoral artery catheter. Beat-to-beat data were analyzed to calculate power spectra of systolic blood pressure (SBP) and pulse interval. After euthanasia, mesenteric fat pads were removed and weighted and total blood was stored for later analysis of lipid profile. Consumption of a HFD increased blood pressure (BP), pulse pressure, low frequency BP variability, BW gain, fat pad stores and induced dyslipidemia. Interestingly, prior physical training was able to partially protect against this rise in BP and body fat stores. Prior physical training did not totally protect against the effects of HFD consumption but previously trained animals did demonstrate resistance to the development of cardiometabolic alterations, which illustrate that the benefits of physical training may be partially maintained even after 30 days of detraining period.

Ameliorative role of a combination of chitosan, calcium, vitamins A and E against high fat diets-induced adverse effects in rats

BackgroundChitosan is a promising natural source for controlling obesity. Obese people tend to use supplementary nutrients to compensate for their deficiencies in their diets. The present study aimed to investigate the combined effect of chitosan, calcium, and vitamins A and E supplements against the adverse effects of high-fat diet consumption in rats.MethodsTwenty-five male albino rats were assigned into five equal groups. Control rats were fed standard basal diet (SBD). Another group was fed high-fat diet (HFD) without supplements. The other three groups were fed HFD containing 0, 400, and 800 mg of chitosan per kilogram diet, in presence of calcium and vitamins A and E supplements, daily for 10 weeks.ResultsAs compared to controls, rats fed HFD without supplements showed significant elevations in body weight gain, feed consumption, relative weights of the heart and liver, serum levels of total cholesterol, triglycerides, low-density lipoprotein cholesterols, very low-lipoprotein triglycerides, urea, creatinine, and malondialdehyde, as well as serum activities of alanine and aspartate aminotransferases, alkaline phosphatase, and creatine kinase. Moreover, significant declines in the relative kidney weight, serum levels of high-density lipoprotein cholesterols, total proteins, albumin, globulin, calcium, vitamins A and E, erythrocyte glutathione content, and superoxide dismutase activity were recorded. Histopathological alterations were observed in rats fed HFD with or without supplements. On contrary, rats fed HFD containing chitosan and supplements showed remarkable improvement in all the studied parameters towards control values, in dose-dependent manner.ConclusionChitosan, calcium, and vitamins A and E attenuated the adverse effects caused by HFD intake in rats.

The effect of high-fat diet consumption on appetitive instrumental behavior in rats

Evidence now indicates that the chronic consumption of high-calorie foods, such as a high-fat diet (HFD), is associated with impaired control over food-seeking, yet the extent of this alteration is not fully understood. Using different reinforcement schedules, we evaluated whether HFD intake from weaning to adulthood modifies instrumental responding and induces a shift from goal-directed actions to habitual responding. We first observed reduced instrumental performance and motivation for a food reward in HFD-fed rats trained under schedules of reinforcement that facilitate habitual responding [Random Interval (RI)]. However, this deficit was alleviated if rats trained under RI were subsequently trained with reinforcement schedules that promote goal-directed strategies [Random Ratio (RR)]. Using an outcome devaluation procedure, we then demonstrated that consumption of a HFD promoted habitual behavior in rats trained under RI but not RR schedules. Finally, extended HFD exposure did not interfere with the ability of RR training to overcome impaired RI instrumental performance and to favor goal-directed behavior. These results indicate that chronic consumption of a HFD changes the co-ordination of goal-directed actions and habits and that alteration of food-seeking may be reversed under particular behavioral conditions.

Shared Neuropathological Characteristics of Obesity, Type 2 Diabetes and Alzheimer's Disease: Impacts on Cognitive Decline.

In the past few decades, the prevalence of obesity and type 2 diabetes mellitus (T2DM), as well as older individuals at risk for Alzheimer’s disease (AD), has increased. While the consumption of diets high in fat (total and saturated) have been linked to increased risk of AD, diets rich in antioxidants, polyunsaturated fats, and omega-3 fatty acids are associated with decreased risk. Additionally, AD patients are at increased risk for developing T2DM. Recent research suggests that there are stronger similarities between AD and T2DM than have previously been considered. Here we review the neurocognitive and inflammatory effects of high-fat diet consumption, its relationship to AD, and the treatment potential of dietary interventions that may decrease risk of cognitive decline and other associated neuropathological changes, such as insulin resistance, oxidative stress, and chronic inflammatory processes.

Wheel-running activity modulates circadian organization and the daily rhythm of eating behavior

Consumption of high-fat diet acutely alters the daily rhythm of eating behavior and circadian organization (the phase relationship between oscillators in central and peripheral tissues) in mice. Voluntary wheel-running activity counteracts the obesogenic effects of high-fat diet and also modulates circadian rhythms in mice. In this study, we sought to determine whether voluntary wheel-running activity could prevent the proximate effects of high-fat diet consumption on circadian organization and behavioral rhythms in mice. Mice were housed with locked or freely rotating running wheels and fed chow or high-fat diet for 1 week and rhythms of locomotor activity, eating behavior, and molecular timekeeping (PERIOD2::LUCIFERASE luminescence rhythms) in ex vivo tissues were measured. Wheel-running activity delayed the phase of the liver rhythm by 4 h in both chow- and high-fat diet-fed mice. The delayed liver phase was specific to wheel-running activity since an enriched environment without the running wheel did not alter the phase of the liver rhythm. In addition, wheel-running activity modulated the effect of high-fat diet consumption on the daily rhythm of eating behavior. While high-fat diet consumption caused eating events to be more evenly dispersed across the 24 h-day in both locked-wheel and wheel-running mice, the effect of high-fat diet was much less pronounced in wheel-running mice. Together these data demonstrate that wheel-running activity is a salient factor that modulates liver phase and eating behavior rhythms in both chow- and high-fat-diet fed mice. Wheel-running activity in mice is both a source of exercise and a self-motivating, rewarding behavior. Understanding the putative reward-related mechanisms whereby wheel-running activity alters circadian rhythms could have implications for human obesity since palatable food and exercise may modulate similar reward circuits.

Neuronal Androgen Receptor Regulates Insulin Sensitivity via Suppression of Hypothalamic NF-κB–Mediated PTP1B Expression

Clinical investigations highlight the increased incidence of metabolic syndrome in prostate cancer (PCa) patients receiving androgen deprivation therapy (ADT). Studies using global androgen receptor (AR) knockout mice demonstrate that AR deficiency results in the development of insulin resistance in males. However, mechanisms by which AR in individual organs coordinately regulates insulin sensitivity remain unexplored. Here we tested the hypothesis that functional AR in the brain contributes to whole-body insulin sensitivity regulation and to the metabolic abnormalities developed in AR-deficient male mice. The mouse model selectively lacking AR in the central nervous system and AR-expressing GT1-7 neuronal cells were established and used to delineate molecular mechanisms in insulin signaling modulated by AR. Neuronal AR deficiency leads to reduced insulin sensitivity in middle-aged mice. Neuronal AR regulates hypothalamic insulin signaling by repressing nuclear factor-κB (NF-κB)–mediated induction of protein-tyrosine phosphatase 1B (PTP1B). Hypothalamic insulin resistance leads to hepatic insulin resistance, lipid accumulation, and visceral obesity. The functional deficiency of AR in the hypothalamus leads to male mice being more susceptible to the effects of high-fat diet consumption on PTP1B expression and NF-κB activation. These findings suggest that in men with PCa undergoing ADT, reduction of AR function in the brain may contribute to insulin resistance and visceral obesity. Pharmacotherapies targeting neuronal AR and NF-κB may be developed to combat the metabolic syndrome in men receiving ADT and in elderly men with age-associated hypogonadism.

High-fat diet alters the dopamine and opioid systems: effects across development.

Consumption of a high-fat diet has been linked to obesity, dyslipidemia and cardiovascular disease. Less well appreciated are adverse effects on the brain and behavior. Recent research has shown that consumption of a high-fat diet can alter gene expression within the brain, and the dopamine and opioid neurotransmitter systems appear to be vulnerable to dysregulation. This review will focus on recent reports in both humans and animal models that describe adverse effects of high-fat diet consumption on the central reward circuitry. In addition, the importance of different development windows will be discussed, with effects observed in both the prenatal/perinatal time period and with chronic high-fat diet consumption in adulthood.

Efficiency of Intermittent Exercise on Adiposity and Fatty Liver in Rats Fed With High‐fat Diet

This study aimed to examine and compare the effects of continuous or intermittent exercises on adiposity and fatty liver in rats fed with high-fat diet. Wistar rats were divided according to diet composition-chow diet (C) or high-fat diet (H)-and kinds of exercise-sedentary (S), continuous (CE), or intermittent (IE) exercises. The CE group swam 90 min/day, and the IE group swam 3 x 30 min/day (at 4-h intervals between sessions); both groups exercised 5 days/week during 8 weeks. Body weight and food intake were recorded daily. Lipogenesis rate in vivo was determined by the incorporation of (3)H(2)O into saponified lipids in retroperitoneal (RET), epididymal (EPI), and visceral (VIS) white adipose tissues, brown adipose tissue (BAT), liver (L), and gastrocnemius muscle (GAST) using the gravimetric method. Total cholesterol, high-density lipoprotein (HDL)-cholesterol, and triacylglycerol (TG) were analyzed. The major finding of this study is that IE was more efficient than CE in reducing the adverse effects of high-fat diet and sedentarism. There was an improvement in the lipid profile and a reduction in food intake, body weight gain, visceral and central adiposity, and fatty liver, contributing to the control of obesity and other comorbidities, including nonalcoholic fat liver diseases. Earlier studies have discussed the effects of diet consumption on adiposity and their relation to chronic diseases and obesity. This study discusses the effects of high-fat diet consumption and the different kinds of exercise on weight gain, adiposity, fatty liver, and lipid profile in rats. The results may depend on the exercise, time of each session, age, gender, and experimental period.