Sucrose Diet Research Articles

#4945 NEPHROPROTECTIVE EFFECTS OF DIPEPTIDYL PEPTIDASE–IV INHIBITORS FROM PHENOLIC RICH FRACTION OF TRIGONELLA FOENUM IN DIABETIC NEPHROPATHY RATS

Abstract Background and Aims The most common effect of renal disease in the world is diabetic nephropathy (DN). Dipeptidyl peptidase–IV (DPP-IV) enzyme is most abundant present in kidney, which is increased in diabetic nephropathy. A novel approach to treat type 2 diabetes mellitus (T2DM) along with DN, based on incretin hormones: glucagon-like peptide-1 (GLP-1) which regulated by DPP-IV. We hypothesized that DPP-IV inhibitors isolated from phenolic rich fraction of Trigonella foenum (TF) will regulate DPP-IV activity as well as DN: in-vivo; in-silico and kidney histology. Method DPP-IV inhibitors from phenolic rich fraction of TF in high sucrose diet along with dexamethasone induced T2DM was explored in-vivo in rat. Apart from serum glucose, DPP-IV, and inhibition activity, HbA1c, Insulin was estimated. We also examined GLP-1, albuminuria, and antioxidant properties in kidney tissue along with histology. Molecular docking of phenolic rich fraction (Gallic acid) of TF with DPP-IV Results High sucrose diet with Dexamethasone administration (1 mg /kg BW 45 days) increased concentration of serum glucose, DPP-IV and albuminuria, cholesterol and renal LPO with increase in tissue antioxidant to scavenging free radicals generated by oxidative stress, but after some time antioxidants such as SOD, CAT, GSH was decreased. However, after administration of phenolic rich fraction of TF, DPP-IV inhibition activity increase in TF (71.1%), as compared to Sitagliptin (89.5%) with significant reduction in levels of glucose, albuminuria, TC, TG and with increased Insulin and GLP-1. Kidney histology showed some significant change as compared to diabetes control. Isolated Gallic acid depicts the conformer and affinity energy was – 5.3 and distance from RMSD i.b was 38.669. Sitagliptin depicted the conformer and affinity energy was – 8.9 and distance from RMSD i.b was 3.826. Conclusion DPP-IV inhibitors isolated from TF are nephroprotective, antioxidant with novel antidiabetic properties. DPP-IV inhibition lower blood glucose by decreasing DPP-IV activity, albuminuria and increasing levels of GLP-1

Diet quality influences nutrient retention and reproductive fitness of the biocontrol agent Hadronotus pennsylvanicus (Hymenoptera: Scelionidae)

Diet can have a direct influence on the reproductive success of parasitoid wasps. For synovigenic parasitoids, the nutrients obtained from floral resources, such as nectar and pollen, play a vital role in fueling bodily functions and physiological energy expenditure incurred from reproduction. Insufficient access to nutrient-rich diets can lead to lower rates of reproductive fitness, therefore reducing the efficacy of biocontrol. Here, a study was conducted to evaluate the influence of diet quality on nutrient retention and reproductive fitness of the egg parasitoid Hadronotus pennsylvanicus (Hymenoptera: Scelionidae), a prospective biocontrol agent for the leaffooted bug Leptoglossus zonatus (Heteroptera: Coreidae), a primary pest of almonds and pistachios. Newly emerged parasitoid females were provided host eggs every other day accompanied by diets of varying sucrose concentrations (source of carbohydrates) and pollen (source of lipid and proteins). The sucrose concentration in the diet, regardless of pollen content, significantly increased the survival and lifetime fecundity of female H. pennsylvanicus. While wasps fed high sucrose diets depleted bodily sugars, glycogen, and lipids at a slower rate than wasps fed low sucrose diets, there was no effect on bodily protein levels. Given these findings, further research is now needed to identify floral resources that are compatible, attractive, and nutritionally-sufficient for optimal H. pennsylvanicus reproductive fitness, which could lead to enhanced parasitism of L. zonatus in crop systems.

Diet-Induced Obese Male Mice Treated with a Rationally Designed P450 8B1 Inhibitor for 28 Days Successfully Increased CDCA to CA Ratios but Lacked Improved Glucose Tolerance and Body Weight

Altering the bile acid composition by inhibiting cytochrome P450 8B1 enzyme (CYP8B1) activity results in a decrease in the production of cholic acid (CA, 12α-hydroxylated bile acids) while increasing chenodeoxycholic acid (CDCA). Previous studies have shown that knocking out the Cyp8b1 gene in mice protects against diet-induced obesity and improves glucose tolerance and fat deposition in the liver. The objective of this study was to test the hypothesis that the inhibition of P450 8B1 enzyme activity with a rationally designed small molecule drug would alleviate diet-induced obesity and improve metabolic health. Male C57BL/6J mice (8-10 weeks old) were fed a high-fat and high sucrose (HF) diet over 10 weeks. When mice in the HF group were obese and developed glucose intolerance, half of the mice were treated with P450 8B1 inhibitor (HF/D), and the other half were treated with vehicle (HF/V, 20% β-hydroxypropyl cycolodextrin in the PBS). Mice fed a low fat and low sucrose diet treated with vehicle were used as a reference control (LF/V). Mice in the HF/D group were treated with 100 mg/kg/day, while mice in the vehicle groups (HF/V and LF/V) were administered with the same volume of vehicle. All mice were treated at the same time each morning by oral gavage for 28 days. Bodyweight and food intake were measured weekly. Glucose (GTT)- and insulin tolerance (ITT) tests were conducted before treatment and after treatment. Stool samples were extracted to measure the amount of CDCA and CA by high-resolution mass spectrometry. We found that the HF/D group did not have altered body weight, food intake, and fat composition compared to the HF/V group for the duration of the treatment (28 days). In addition, the HF/D group did not show any improvement in GTT and ITT during the 28 days of treatment. Despite these results related to body weight, GTT, and ITT, the stool samples from the HF/D group generally had a larger ratio of CDCA to CA compared to the HF/V group (CDCA/CA ratios for HF/D vs. HF/V were: 5.5, 9.4, 2.7, 4.1, 3.3 vs. 0.5, 1.5, 2.2, 8.4), suggesting that the inhibition of P450 8B1 did occur in the HFD group. The lipid droplet in the liver also decreased in some mice treated in the HF/D group. Our results suggest that a newly designed inhibitor that has a higher affinity towards the P450 8B1 enzyme relative to our originally designed inhibitor may reduce fatty liver diseases by modifying bile acid composition more effectively. Alternatively, future studies are warranted where the HF mice will be treated for a duration longer than 28 days to check whether the CDCA/CA ratio matches the physiological alterations including body weight and glucose homeostasis. This study was supported by the National Institute of Health [NIH, NIGMS, grant GM125603] to E. Chung This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Oral Carnosine Supplementation Restores Insulin Sensitivity but not Glucose Tolerance in Mice With Glutathione Peroxidase-4 Deficiency

Obesity presents in about 90% of the diabetic patients, a risk factor that makes them more susceptible to cardiometabolic disorders, particularly insulin resistance and ultimately T2 diabetes. Increased oxidative stress and specifically lipid peroxidation are known to be major pathogenic factors driving these disorders in obesity. We recently reported that diabetic patients were found to have significantly lower level of glutathione peroxidase 4 (GPx4)- an antioxidant selenoenzyme which neutralizes lipid peroxides. Carnosine, a histidine-containing dipeptide which is highly concentrated in muscle and brain, has shown a remarkable therapeutic potential for preventing diabetes and its complications when administered orally in experimental and clinical studies of obesity. The extent to which carnosine can mitigate these disorders in the presence of GPx4 deficiency is not known however, and this is critical to determining its efficacy in diabetes patients. To address this question, wild-type (WT) and GPx4+/− male were randomly assigned to either standard chow (CNTL) or high fat high sucrose diet (HFHS) for 16 weeks. Seven weeks after starting the diet, half of the HFHS diet groups received 80 mM carnosine oral carnosine supplementation in their drinking water. Glucose and insulin tolerance tests performed 8 weeks after starting the diet revealed that carnosine significantly improved glucose tolerance in obese WT (P<0.05) but not obese GPx4+/− mice. Interestingly, carnosine treatment did significantly improve insulin sensitivity in the GPx4+/− mice, and to a lesser extent the WT mice. At the molecular level, we observed that HFHS diet up-regulated GPx4 protein in cardiac tissue from WT but not GPx4+/− mice, and protein oxidation was significantly reduced with carnosine treatment in both genotypes. Collectively, these findings indicate that carnosine supplementation could potentially mitigate insulin resistance even in patients with compromised antioxidant capacity (e.g., diabetes). Further analysis is in progress to evaluate the effectiveness of carnosine supplementation on additional cardiometabolic complications that are associated with diet induced obesity. This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Effects of Fermented Tempeh Using Rhizopus oligosporus and Lactobacillus rhamnosus GG on Body Weight, Lee Index, High Sensitivity C Reactive Protein and Lipid Profile of Obese Rats

Background: Tempeh is a fermented soybean containing isoflavones that shows good benefits again obesity. Co-fermentation of tempeh using Lactobacillus rhamnosus GG could increase the bioavailability of isoflavones.Objective: This study aimed to determine the effect of co-fermented tempeh using Lactobacillus rhamnosus GG (tLGG) on body weight (B.W.), Lee Index, high sensitivity C Reactive Protein (hs-CRP), and lipid profile of obese rats. Total flavonoid and genistein were also measured.Methods: Male Sprague Dawley rats (n=36, 200-to-215-gram, age eight weeks) were orally administered high fat and high sucrose diet (HFHS diet) for two weeks to induce obesity. After obesity was confirmed by checking Lee Index, rats were divided into six group and administered orally standard diet (normal control), HFHS diet (negative control), HFHS diet and 120 mg/kg B.W./day-orlistat (positive control), HFHS diet and 60 mg/kg B.W./day standard tempeh with Rhizopus oligosporus (tS), HFHS diet and 60 mg/kg B.W./day tLGG, HFHS diet and 120 mg/kg B.W./day tLGG for four weeks. Body weight, Lee Index, hs-CRP, and lipid profile were analyzed. Total flavonoid and genistein were analyzed.Results: 120 mg/kg B.W./day tLGG group exhibited significantly lower body weight gains, Lee Index, hs-CRP, triglyceride, total cholesterol, LDL, and higher HDL compared to negative control and tS group (p<0,001), however, positive control group exhibited lower body weight gains compared to tLGG group (p<0,001). Nevertheless, tLGG group exhibited lower Lee Index compared to positive control group. tLGG showed higher flavonoid and genistein level than tS.Conclusion: Administration of 120 mg/kg B.W./day tLGG showed significantly lower Lee Index compared to all groups given HFHS diet, however, positive control group showed lower body weight gains compared to tLGG group. tLGG also improved hs-CRP and lipid profile two times better than negative control group. tLGG increased total flavonoids and genistein level.

High-Sucrose Diet Exposure on Larvae Contributes to Adult Fecundity and Insecticide Tolerance in the Oriental Fruit Fly, Bactrocera dorsalis (Hendel)

Bactrocera dorsalis (Hendel) (Diptera: Tephritidae) is one of the broad host ranges and economically-important insect pests in tropical and subtropical areas. A wide range of hosts means they have strong adaptation ability to changes in dietary macronutrients (e.g., sucrose and protein). However, the effects of dietary conditions on the phenotypes and genotypes of B. dorsalis are still unclear. In this study, we aimed to investigate the effects of larval dietary sucrose on the life history traits and stress tolerance of B. dorsalis, and its defense response at the molecular level. The results showed that low-sucrose (LS) induced decreased body size, shortened developmental duration, and enhanced sensitivity to beta-cypermethrin. Otherwise, high-sucrose (HS) diet increased developmental duration, adult fecundity, and tolerance to malathion. Based on transcriptome data, 258 and 904 differentially expressed genes (DEGs) were identified in the NS (control) versus LS groups, and NS versus HS groups, respectively. These yielded DEGs were relevant to multiple specific metabolisms, hormone synthesis and signaling, and immune-related pathways. Our study will provide biological and molecular perspective to understand phenotypic adjustments to diets and the strong host adaptability in oriental fruit flies.

303 Investigation of the antibacterial and regenerative properties of a novel AHA dental coating for the treatment of deep caries

OBJECTIVES/GOALS: Our objective is to investigate the antibacterial and regenerative properties of a novel AHA dental coating for the prevention and treatment of deep caries (cavities). Further, we aim to investigate and compare these properties through in vivo murine models and assessment on human saliva samples and human pulpal cells collected from clinical samples. METHODS/STUDY POPULATION: In vitro antibacterial studies were performed by collecting and culturing human salivary bacteria with AHA substrates and quantifying survival of cariogenic Sm (S. mutans). In vivo, C57BL/6 mice were treated with AHA composite fillings, infected with Sm clinical isolates, and fed a high sucrose diet with cavity formation assessment after 6 weeks. To evaluate regeneration, mice were similarly given composite with AHA or MTA (standard of care) upon pulpal exposure with regeneration quantified by microCT and histological analysis of dentin bridge formation, ALP production, and odontoblast migration. In vitro, AHA substrates were cultured with MC3T3-E1 pre-osteoblast cells and dental pulp stem cells obtained from clinical samples over 21 days, with mineralization and ALP assessed indicating osteogenesis. RESULTS/ANTICIPATED RESULTS: In vivo studies have shown the reduction of cavity formation in mice treated with AHA as well as dentin regeneration upon pulpal exposure using microCT and histological image analysis. Coinciding with these findings, AHA substrates eradicated cariogenic Sm in human saliva samples and single species cultures in vitro. Further, preliminary results in vitro have shown increased mineralization of MC3T3-E1 cells when cultured with AHA substrates in comparison to uncoated substrates. We anticipate similar increased mineralization as well as increased ALP production of human pulpal stem cells from clinical samples when cultured with AHA substrates, suggesting osteogenesis. Further, we anticipate increased odontoblast migration and ALP production upon additional analysis of in vivo tissue samples. DISCUSSION/SIGNIFICANCE: This work will elucidate the antibacterial and regenerative properties of AHA dental coatings. These results further support the translation of AHA coatings into the clinic as a novel therapeutic for the prevention and treatment of dental decay, which may overcome the limitations associated with the current treatments.

High Fat/High Sucrose Diet Consumption Worsens Comorbid Metabolic Outcomes In An Early Life Stress Model Of Urologic Chronic Pelvic Pain In Mice

High Fat/High Sucrose Diet Consumption Worsens Comorbid Metabolic Outcomes In An Early Life Stress Model Of Urologic Chronic Pelvic Pain In Mice

EXCESS DIETARY SUGAR ALTERS COLONOCYTE METABOLISM AND IMPAIRS THE EARLY PROLIFERATIVE RESPONSE TO DAMAGE

The colonic epithelium requires continuous renewal by crypt resident intestinal stem cells (ISCs) and transit amplifying (TA) cells to maintain barrier integrity, especially after inflammatory damage. An important regulator of ISC and TA cell function is dietary metabolites which can affect their proliferative capacity. Over the last 150 years, the diet of high-income countries contains increasing amounts of simple sugars, such as sucrose, but whether excess sugar affects the function of ISCs and TA cells directly is unknown. We used a combination of 3-dimensional colonoids and a mouse model of colon damage/repair (DSS colitis) to demonstrate the direct effect of sugar on the transcriptional, metabolic, and regenerative functions of crypt ISCs and TA cells. We demonstrate that high sugar conditions directly limit murine and human colonoid development, which is associated with a reduction in the expression of proliferative and key stem cell gene signatures. Further, high-glucose conditions led to the accumulation of glycolytic metabolite pyruvate in colonoids, with a concomitant decrease in ATP, suggesting impaired glycolytic fuel metabolism. Treatment of colonoids with DCA, which forces pyruvate into the TCA cycle, restored their growth, ATP levels, and the expression of proliferation and stem cell gene signatures. Similarly, DSS treatment of mice fed a high sugar diet led to massive irreparable damage that was independent of the colonic microbiota and its metabolites. Metabolic analyses of crypt cells from high-sucrose-fed mice revealed increased glycolytic potential without a commensurate increase in aerobic respiration. Rather, epithelium from high-sucrose-fed mice has increased mitochondrial content, without increased levels of ATP, further demonstrating impaired oxidative phosphorylation and fuel metabolism. Finally, we demonstrated impaired proliferative potential of ISCs and reduced number of TA direct daughter cells in high-sucrose-fed mice with DSS damage. Taken together, our results indicate that short-term, excess dietary sucrose can directly modulate intestinal crypt cell metabolism and inhibit ISC/TA cell regenerative proliferation. This knowledge may inform diets that better support the treatment of acute intestinal injury, as is seen in patients with an acute flare of Ulcerative Colitis.

Resveratrol and Dulaglutide ameliorate adiposity and liver dysfunction in rats with diet-induced metabolic syndrome: Role of SIRT-1 / adipokines / PPARγ and IGF-1

BackgroundAdiposity and non-alcoholic fatty liver disease (NAFLD) are common characteristics of metabolic syndrome (MS). Understanding the underlying pathogenesis is crucial for the development of new remedies. Resveratrol controls obesity and glycemic disorders in patients with MS.ObjectivesThis study aimed to evaluate the effect of resveratrol and dulaglutide on adipose tissues and liver in rats with MS, declaring their possible mechanisms.MethodsRats allocated as Control, MS (induced by a high fat/ high sucrose diet for eight weeks), MS + Resveratrol (30 mg/kg/day orally), and MS + Dulaglutide (0.6 mg/kg twice weekly SC); drugs administration was in the last four weeks. Serum biochemical measurements were done. Liver and visceral fat were processed for biochemistry, histopathology, and immunohistochemistry.ResultsMS results demonstrated significantly increased systolic and diastolic blood pressure, anthropometric measurements, serum levels of alanine aminotransferase (ALT), glycemic indices, and lipids with decreased HDL-C. Tissue levels of leptin, malondialdehyde (MDA), and TNF-α reactivity significantly increased. Expression of adiponectin, PPARγ, and insulin growth factor-1 (IGF-1) decreased. Also, Western blotting mRNA gene expression of liver SIRT-1 was down-regulated. Resveratrol and dulaglutide significantly and effectively reversed MS complexity, ameliorating all findings, particularly NAFLD and adiposity-induced inflammation. Resveratrol significantly appears superior to dulaglutide regarding the effects on hemodynamics, lipids, adipokines, IGF-1 levels, and adipocyte size. Parallel, dulaglutide has more influence on glycemic control.ConclusionProtective effects of the drugs may be through correlations between SIRT-1/adipokines/IGF-1 and PPARγ, improving the cross-talk between insulin resistance, obesity markers, liver dysfunction, and TNF-α. Promising multi-beneficial therapies of resveratrol or dulaglutide in MS are recommended clinically for this purpose.Graphical Showing the Experimental Design

Experimental diets dictate the metabolic benefits of probiotics in obesity

ABSTRACT Growing evidence supports the use of probiotics to prevent or mitigate obesity-related dysmetabolism and non-alcoholic fatty liver disease (NAFLD). However, frequent reports of responders versus non-responders to probiotic treatment warrant a better understanding of key modifiers of host–microbe interactions. The influence of host diet on probiotic efficacy, in particular against metabolic diseases, remains elusive. We fed C57BL6/J mice a low fat reference diet or one of two energy-matched high fat and high sucrose diets for 12 weeks; a classical high fat diet (HFD) and a customized fast food-mimicking diet (FFMD). During the studies, mice fed either obesogenic diet were gavaged daily with one of two probiotic lactic acid bacteria (LAB) strains previously classified as Lactobaccillus, namely Limosilactobacillus reuteri (L. reuteri)or Lacticaseibacillus paracaseisubsp. paracasei (L. paracasei), or vehicle. The tested probiotics exhibited a reproducible efficacy but dichotomous response according to the obesogenic diets used. Indeed, L. paracaseiprevented weight gain, improved insulin sensitivity, and protected against NAFLD development in mice fed HFD, but not FFMD. Conversely, L. reuteri improved glucoregulatory capacity, reduced NAFLD development, and increased distal gut bile acid levels associated with changes in predicted functions of the gut microbiota exclusively in the context of FFMD-feeding. We found that the probiotic efficacy of two LAB strains is highly dependent on experimental obesogenic diets. These findings highlight the need to carefully consider the confounding impact of diet in order to improve both the reproducibility of preclinical probiotic studies and their clinical research translatability.

Combined Intake of Fish Oil and D-Fagomine Prevents High-Fat High-Sucrose Diet-Induced Prediabetes by Modulating Lipotoxicity and Protein Carbonylation in the Kidney.

Obesity has been recognized as a major risk factor for chronic kidney disease, insulin resistance being an early common metabolic feature in patients suffering from this syndrome. This study aims to investigate the mechanism underlying the induction of kidney dysfunction and the concomitant onset of insulin resistance by long-term high-fat and sucrose diet feeding in Sprague Dawley rats. To achieve this goal, our study analyzed renal carbonylated protein patterns, ectopic lipid accumulation and fatty acid profiles and correlated them with biometrical and biochemical measurements and other body redox status parameters. Rats fed the obesogenic diet developed a prediabetic state and incipient kidney dysfunction manifested in increased plasma urea concentration and superior levels of renal fat deposition and protein carbonylation. An obesogenic diet increased renal fat by preferentially promoting the accumulation of saturated fat, arachidonic, and docosahexaenoic fatty acids while decreasing oleic acid. Renal lipotoxicity was accompanied by selectively higher carbonylation of proteins involved in the blood pH regulation, i.e., bicarbonate reclamation and synthesis, amino acid, and glucose metabolisms, directly related to the onset of insulin resistance. This study also tested the combination of antioxidant properties of fish oil with the anti-diabetic properties of buckwheat D-Fagomine to counteract diet-induced renal alterations. Results demonstrated that bioactive compounds combined attenuated lipotoxicity, induced more favorable lipid profiles and counteracted the excessive carbonylation of proteins associated with pH regulation in the kidneys, resulting in an inhibition of the progression of the prediabetes state and kidney disease.

Long-term administration of Western diet induced metabolic syndrome in mice and causes cardiac microvascular dysfunction, cardiomyocyte mitochondrial damage, and cardiac remodeling involving caveolae and caveolin-1 expression

BackgroundLong-term consumption of an excessive fat and sucrose diet (Western diet, WD) has been considered a risk factor for metabolic syndrome (MS) and cardiovascular disease. Caveolae and caveolin-1 (CAV-1) proteins are involved in lipid transport and metabolism. However, studies investigating CAV-1 expression, cardiac remodeling, and dysfunction caused by MS, are limited. This study aimed to investigate the correlation between the expression of CAV-1 and abnormal lipid accumulation in the endothelium and myocardium in WD-induced MS, and the occurrence of myocardial microvascular endothelial cell dysfunction, myocardial mitochondrial remodeling, and damage effects on cardiac remodeling and cardiac function.MethodsWe employed a long-term (7 months) WD feeding mouse model to measure the effect of MS on caveolae/vesiculo-vacuolar organelle (VVO) formation, lipid deposition, and endothelial cell dysfunction in cardiac microvascular using a transmission electron microscopy (TEM) assay. CAV-1 and endothelial nitric oxide synthase (eNOS) expression and interaction were evaluated using real-time polymerase chain reaction, Western blot, and immunostaining. Cardiac mitochondrial shape transition and damage, mitochondria-associated endoplasmic reticulum membrane (MAM) disruption, cardiac function change, caspase-mediated apoptosis pathway activation, and cardiac remodeling were examined using TEM, echocardiography, immunohistochemistry, and Western blot assay.ResultsOur study demonstrated that long-term WD feeding caused obesity and MS in mice. In mice, MS increased caveolae and VVO formation in the microvascular system and enhanced CAV-1 and lipid droplet binding affinity. In addition, MS caused a significant decrease in eNOS expression, vascular endothelial cadherin, and β-catenin interactions in cardiac microvascular endothelial cells, accompanied by impaired vascular integrity. MS-induced endothelial dysfunction caused massive lipid accumulation in the cardiomyocytes, leading to MAM disruption, mitochondrial shape transition, and damage. MS promoted brain natriuretic peptide expression and activated the caspase-dependent apoptosis pathway, leading to cardiac dysfunction in mice.ConclusionMS resulted in cardiac dysfunction, remodeling by regulating caveolae and CAV-1 expression, and endothelial dysfunction. Lipid accumulation and lipotoxicity caused MAM disruption and mitochondrial remodeling in cardiomyocytes, leading to cardiomyocyte apoptosis and cardiac dysfunction and remodeling.

Evaluation of fetoplacental oxygenation in a rat model of gestational diabetes mellitus using BOLD-MRI at 7.0-T

Objective: To compare the differences in blood oxygen level-dependent (BOLD) parameters following maternal hyperoxia between normal pregnancy and pregnancy in the rat model of gestational diabetes mellitus (GDM). Methods: GDM was induced by high-fat and sucrose diet (HFS) combined with an intraperitoneal injection of streptozotocin (STZ). On embryonic day 19 (E19), the two groups of pregnant rats were imaged using a 7.0-T animal MRI scanner. TurboRARE was initially used to localize the fetoplacental units (FPUs). Next, multiple gradient echo BOLD was performed during the air and oxygen inhalation periods. T2* map was then generated, and the baseline T2* and absolute changes in T2* value (ΔT2*, difference between T2*oxy and T2*air) were calculated. Following the MRI scan, the placentas and fetuses were aseptically stripped, weighed, and immunostained. Results: Nine rats were used in this study. After maternal oxygen inhalation, T2* increased significantly in all subjects in both groups. The ΔT2* for the placenta (5.97 vs. 7.81 msec; P = 0.007) and fetal brain (2.23 vs. 3.97 msec; P = 0.005) differed significantly between the GDM and control groups. Histochemical detection of placental glycogen content and inflammatory cytokines (IL-6 and TNF-α) showed significantly higher levels in the GDM than in the normal placenta. Conclusions: BOLD-MRI revealed abnormalities in the fetoplacental response to maternal hyperoxygenation in rats with GDM. We believe that this approach can potentially be used to evaluate placental dysfunction and assess the state of the fetus during pregnancy with GDM.

Differential disruption on glucose and insulin metabolism in two rat models of diet-induced obesity, based on carbohydrates or lipids.

Obesity is a relevant health public issue and is the main factor for glucose metabolism dysregulation and diabetes progression; however, the differential role of a high-fat diet or high sugar diet consumption on glucose metabolism and insulin processing is not well understood and has been scarcely described. Our research aimed to analyze the effects of chronic consumption of both high sucrose and high-fat diets on glucose and insulin metabolism regulation. Wistar rats were fed with high-sugar or high-fat diets for 12months; after that, fasting glucose and insulin levels were measured along with a glucose tolerance test (GTT). Proteins related to insulin synthesis and secretion were quantified in pancreas homogenates, whereas islets were isolated to analyze ROS generation and size measurement. Our results show that both diets induce metabolic syndrome, linked with central obesity, hyperglycemia, and insulin resistance. We observed alterations in the expression of proteins related with insulin synthesis and secretion, along with diminution of Langerhans islets size. Interestingly, the severity and number of alterations were more evident in the high-sugar diet than in the high-fat diet group. In conclusion, obesity and glucose metabolism dysregulation induced by carbohydrate consumption, led to worst outcomes than high-fat diet.

Abstract PD12-05: PD12-05 Adipocyte directed vaccination to reduce the risk of breast cancer

Abstract Background: Obesity is an important risk factor for breast cancer and women with metabolic syndrome may be at the highest risk. Infiltration of CD8 T-cells into fat is an early event in obesity. Type I cytokines secreted by CD8 T-cells upregulate costimulatory molecules on enlarged adipocytes. The adipocytes, now antigen presenting cells, further stimulate Type I T-cell activation. The resulting T-cells compete for glucose and fatty acids which leads to metabolic dysfunction in both the adipose tissue and the T-cells themselves. The T-cells are not able to maintain tumor immune surveillance and secretion of adipokines promotes malignant transformation. Immunologic memory prevents inflammation from resolving even if an individual becomes normal weight. Strategies to increase Type II (anti-inflammatory) T-cells in inflamed adipose could have clinical benefit. Methods: We developed a method of CD4 epitope identification that includes functional screening for Th1 or Th2 epitopes. We use a multi-algorithm approach to ensure responsiveness across diverse HLA alleles. We identified Th2 selective epitopes associated with high IL-10 secretion for 6 adipocyte associated antigens that become overexpressed in inflamed adipocytes (IGF-IR, HIF-1a, DUSP1, FABP4, PAI-1 and ATGL). The epitopes were highly homologous between mouse and man (median 100% (range-82-100%). When the epitopes were used to immunize mice, all antigens generated a significant IL-10 response compared to control (p< 0.05). We questioned whether our “adipocyte directed” vaccine (ADVac) could prevent the development of breast cancer in obese mice. Results: First, C57BL/6 mice were fed a high fat high sucrose (HFHS) diet or normal chow. When mice became obese, vaccination with ADVac or adjuvant alone (Alum) was initiated. Four weeks after the final vaccine, visceral adipose tissue showed significantly fewer CD8 T-cells in the obese mice immunized with ADVac as compared to the control, p=0.0011. The decrease in CD8 T-cells was specific for adipose tissue as no change was observed in matched spleen. There was a significant increase in T-regulatory cells in the adipose tissue of mice immunized with ADVac as compared to control, p=0.031. Two weeks after the final vaccine, a glucose tolerance test (GTT) and insulin tolerance (ITT) showed blood glucose concentrations were significantly lower at all time points for the ADVac-immunized obese mice as compared to the control obese mice (p< 0.01 for all). TgMMTV-neu develop aggressive breast cancer when made obese. Ten-week old TgMMTV-neu mice were fed a HFHS diet for 4 weeks, then randomized into 2 cohorts when obese, one cohort receiving the adjuvant only (Alum) and one receiving ADVac. Mice were sacrificed at 31 weeks of age when all controls had developed tumor. ITT showed the glucose levels in the blood were significantly lower in the ADVac group as compared to control (p< 0.0001). Fewer CD8 T-cells were observed in mammary adipose tissue of AdVac immunized mice compared to control (p=0.001). There was significantly less leptin detected in the serum of ADVac vaccinated mice compared to Alum immunized, p=0.024. The median age of tumor development was 25 weeks in controls and 29 weeks in the immunized group (p=0.009). Sixty percent (9/15) of the vaccinated mice were tumor free at study termination, whereas 100% of the control mice had developed tumor. Conclusions: ADVac represents the first vaccine to lower breast cancer risk in obesity. Vaccination corrected metabolic dysfunction as evidenced by reversal of diabetes and prevented breast cancer in the majority of obese ADVac immunized mice. Further studies are ongoing evaluating the systemic distribution of ADVac specific T-cells and the safety of the approach. Citation Format: Mary Disis, Lauren Corulli, Erin R. Rodmaker, Denise Cecil. PD12-05 Adipocyte directed vaccination to reduce the risk of breast cancer [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr PD12-05.

High-sucrose diet-fed male rats show affectations in pubococcygeus reflex activation and myofiber content

In males, the function of the pubococcygeus muscle (Pcm) shows a high androgen dependency. High sucrose intake increases testosterone levels in pubertal male rats. We aimed to analyze the Pcm reflex activity and fiber type in response to a 30 % sucrose diet. Wistar male rats were assigned into two groups: control and sugar. The Pcm electromyographic activity was recorded during the mechanical stimulation of the scrotal skin and penis. We also determined the relative levels of Glut4 expression, glycogen content, myofiber cross-sectional area (CSA), and the content of glycolytic and oxidative with NADH-TR or fast, intermediate, and slow fibers with alkaline (pH 9.4) ATPase histochemistry. The sugar group showed a short Pcm reflex activity, a higher Glut4 expression, and glycogen content; the CSA fibers showed a significant difference in the percentage of fibers with the different transversal areas. The number of nuclei was positively correlated with the CSA of the Pcm fibers. There was also a decrease in oxidative fibers but an increase in glycolytic fibers, while the content of fast muscle fibers increased to the detriment of intermediate and slow fibers. Thus, a high-sugar diet reduced Pcm reflex activity, fiber type, and dysregulation of skeletal muscle energy metabolism.

Once a week consumption of Western diet over twelve weeks promotes sustained insulin resistance and non-alcoholic fat liver disease in C57BL/6 J mice

The Western diet (high in fat and sucrose) consumption is a highly prevalent feature in the whole world, mainly due to the increasing consumption of ultra-processed foods (UPF), which are cheaper and easier-to-eat, as compared to fresh and highly nutritive meals. Epidemiological studies have associated UPF consumption with development of obesity, non-alcoholic fat liver disease (NAFLD) and insulin resistance. For molecular studies, mice fed with Western diets have been used to characterize signaling pathways involved in these diet-induced pathologies. However, these studies fed mice continuously with the diets, which is not compatible with what occurs in real life, when consumption is occasional. Here, we fed mice once-a-week with a high fat, high sucrose (HFHS) diet and compared these animals with those fed continuously with HFHS diet or with a standard diet. Our results show that after a single day of consuming HFHS, animals presented impaired oral glucose tolerance test (oGTT) as compared to control group. Although this impairment was reversed after 24 h consuming regular diet, repetition of HFHS consumption once-a-week aggravated the picture such as after 12-weeks, oGTT impairment was not reversed after 6 days under control diet. Liver steatosis, inflammation, impaired insulin signaling pathway and endoplasmic reticulum stress are similar comparing animals that consumed HFHS once-a-week with those that continuously consumed HFHS, though weekly-fed animals did not gain as much weight. Therefore, we conclude that regimen of one day HFHS plus 6 days normal diet over 12 weeks is sufficient to induce insulin resistance and NAFLD in mice.

MBOAT7-driven lysophosphatidylinositol acylation in adipocytes contributes to systemic glucose homeostasis

We previously demonstrated that antisense oligonucleotide-mediated knockdown of Mboat7, the gene encoding membrane bound O-acyltransferase 7, in the liver and adipose tissue of mice promoted high fat diet-induced hepatic steatosis, hyperinsulinemia, and systemic insulin resistance. Thereafter, other groups showed that hepatocyte-specific genetic deletion of Mboat7 promoted striking fatty liver and NAFLD progression in mice but does not alter insulin sensitivity, suggesting the potential for cell autonomous roles. Here, we show that MBOAT7 function in adipocytes contributes to diet-induced metabolic disturbances including hyperinsulinemia and systemic insulin resistance. We generated Mboat7 floxed mice and created hepatocyte- and adipocyte-specific Mboat7 knockout mice using Cre-recombinase mice under the control of the albumin and adiponectin promoter, respectively. Here, we show that MBOAT7 function in adipocytes contributes to diet-induced metabolic disturbances including hyperinsulinemia and systemic insulin resistance. The expression of Mboat7 in white adipose tissue closely correlates with diet-induced obesity across a panel of ∼100 inbred strains of mice fed a high fat/high sucrose diet. Moreover, we found that adipocyte-specific genetic deletion of Mboat7 is sufficient to promote hyperinsulinemia, systemic insulin resistance, and mild fatty liver. Unlike in the liver, where Mboat7 plays a relatively minor role in maintaining arachidonic acid-containing PI pools, Mboat7 is the major source of arachidonic acid-containing PI pools in adipose tissue. Our data demonstrate that MBOAT7 is a critical regulator of adipose tissue PI homeostasis, and adipocyte MBOAT7-driven PI biosynthesis is closely linked to hyperinsulinemia and insulin resistance in mice.

EXCESS DIETARY SUGAR ALTERS COLONOCYTE METABOLISM AND IMPAIRS THE EARLY PROLIFERATIVE RESPONSE TO DAMAGE

Abstract The colonic epithelium requires continuous renewal by crypt resident intestinal stem cells (ISCs) and transit amplifying (TA) cells to maintain barrier integrity, especially after inflammatory damage. An important regulator of ISC and TA cell function is dietary metabolites which can affect their proliferative capacity. Over the last 150 years, the diet of high-income countries contains increasing amounts of simple sugars, such as sucrose, but whether excess sugar affects the function of ISCs and TA cells directly is unknown. We used a combination of 3-dimensional colonoids and a mouse model of colon damage/repair (DSS colitis) to demonstrate the direct effect of sugar on the transcriptional, metabolic, and regenerative functions of crypt ISCs and TA cells. We demonstrate that high sugar conditions directly limit murine and human colonoid development, which is associated with a reduction in the expression of proliferative and key stem cell gene signatures. Further, high-glucose conditions led to the accumulation of glycolytic metabolite pyruvate in colonoids, with a concomitant decrease in ATP, suggesting impaired glycolytic fuel metabolism. Treatment of colonoids with DCA, which forces pyruvate into the TCA cycle, restored their growth, ATP levels, and the expression of proliferation and stem cell gene signatures. Similarly, DSS treatment of mice fed a high sugar diet led to massive irreparable damage that was independent of the colonic microbiota and its metabolites. Metabolic analyses of crypt cells from high-sucrose-fed mice revealed increased glycolytic potential without a commensurate increase in aerobic respiration. Rather, epithelium from high-sucrose-fed mice has increased mitochondrial content, without increased levels of ATP, further demonstrating impaired oxidative phosphorylation and fuel metabolism. Finally, we demonstrated impaired proliferative potential of ISCs and reduced number of TA direct daughter cells in high-sucrose-fed mice with DSS damage. Taken together, our results indicate that short-term, excess dietary sucrose can directly modulate intestinal crypt cell metabolism and inhibit ISC/TA cell regenerative proliferation. This knowledge may inform diets that better support the treatment of acute intestinal injury, as is seen in patients with an acute flare of Ulcerative Colitis.