High-fat High-sucrose Research Articles

MiR-369-3p ameliorates diabetes-associated atherosclerosis by regulating macrophage succinate-GPR91 signaling.

Diabetes leads to dysregulated macrophage immunometabolism, contributing to accelerated atherosclerosis progression. Identifying critical factors to restore metabolic alterations and promote resolution of inflammation remains an unmet goal. MicroRNAs (miRs) orchestrate multiple signaling events in macrophages, yet their therapeutic potential in diabetes-associated atherosclerosis remains unclear. MiRNA profiling revealed significantly lower miR-369-3p expression in aortic intimal lesions from Ldlr-/- mice on a high-fat sucrose containing (HFSC) diet for 12 weeks. miR-369-3p was also reduced in peripheral blood mononuclear cells (PBMCs) from diabetic patients with coronary artery disease (CAD). Cell-type expression profiling showed miR-369-3p enrichment in aortic macrophages. In vitro, oxLDL treatment reduced miR-369-3p expression in mouse bone marrow-derived macrophages (BMDMs). Metabolic profiling in BMDMs revealed that miR-369-3p overexpression blocked the oxLDL-mediated increase in the cellular metabolite succinate and reduced mitochondrial respiration (OXPHOS) and inflammation (lL-1β, TNF-a, IL-6). Mechanistically, miR-369-3p targeted the succinate receptor (GPR91) and alleviated the oxLDL-induced activation of inflammasome signaling pathways. Therapeutic administration of miR-369-3p mimics in HFSC-fed Ldlr-/- mice reduced GPR91 expression in lesional macrophages and diabetes-accelerated atherosclerosis, evident by a decrease in plaque size and pro-inflammatory Ly6Chi monocytes. RNA-seq analyses showed more pro-resolving pathways in plaque macrophages from miR-369-3p treated mice, consistent with an increase in macrophage efferocytosis in lesions. Finally, a GPR91 antagonist attenuated oxLDL-induced inflammation in primary monocytes from human subjects with diabetes. These findings establish a therapeutic role for miR-369-3p in halting diabetes-associated atherosclerosis by regulating GPR91 and macrophage succinate metabolism.

Abstract 1151: Concurrent Obesity And Chronic Alcohol Consumption Exacerbates Skeletal Muscle Mitochondrial Dysfunction In A Murine Model Of Peripheral Artery Disease (PAD).

PAD causes ischemic mitochondrial and consequent muscle damage in the legs, amplifying patient morbidity and mortality. While obesity and alcoholism are common comorbidities, their impact on PAD myopathy is unclear. We sought to determine the effect of concurrent hindlimb ischemia (HLI), obesity and chronic alcohol consumption on muscle oxidative stress, and mitochondrial and limb function. Methods: Twenty-four male, 24 female, 8 month old C57BL/6 mice received high-fat-sucrose (HFS) or low-fat-sucrose (LFS) diets for 16 weeks, followed by either 20% ethanol (EtOH) added to the drinking water / continued water access for another 12 weeks ( n =12 mice/4 groups). The left femoral artery was then ligated to induce HLI, and mice continued their assigned diets for another 4 weeks. The quadriceps from ischemic and non-ischemic limbs were excised at euthanasia. High-resolution respirometry measured muscle mitochondrial respiration and reactive oxygen species (H 2 O 2 ) output. Muscle oxidative stress and mitochondrial quality control (mitophagy) were assessed enzymatically and by western blot. Results: Compared to LFS animals with/without EtOH access, two-way ANOVA showed post-HLI limb function was lower in HFS+water and HFS+EtOH animals (p<0.05). Mitochondrial respiration was lower in LFS+EtOH, HFS+water, and HFS+EtOH ischemic muscle during electron transport chain Complex I, state 2 (I.2), Complex I, state 3 (I.3) and Complex III versus LFS+water controls (p<0.05), and was further reduced during Complex II and IV in LFS and HFS-ischemic muscle exposed to EtOH (p<0.01). Mitochondrial H 2 O 2 yield was increased in HFS+water and HFS+EtOH ischemic muscle at complexes I.2, I.3, II, III and IV (p<0.05), but not in LFS+EtOH muscle. Oxidative damage (carbonyl accumulation) (p<0.0001) and reduced antioxidant levels (superoxide dismutase (p<0.05) and PGC-1alpha (p<0.001)) was only evident in HFS ischemic muscle with/without EtOH exposure. However, the mitochondrial detoxifying enzyme, aldehyde dehydrogenase-2 (p=0.03), and mitophagy markers LC3II:I ratio (p=0.002) and mitofusins 1 (p=0.02) and 2 (p=0.002), were only reduced in HFS+EtOH muscle. Conclusion: Obesity and chronic alcohol consumption exacerbates muscle mitochondriopathy in mice with HLI.

FINERENONE TREATMENT PREVENTS GLOMERULAR DAMAGE AND RENAL INTERSTITIAL INFLAMMATION IN TYPE 1 DIABETIC RATS WITH CHRONIC KIDNEY DISEASE

Objective: Finerenone (FIN), a non-steroidal mineralocorticoid receptor antagonist, has shown a protective effect on kidney and cardiovascular damage progression in type 1 diabetic Munich Wistar Frömter rats with established chronic kidney disease (CKD). The gradual decline in kidney function in diabetic CKD is due to a thickening of glomerular and Bowman capsule basement membranes, mesangial matrix expansion, and tubulointerstitial fibrosis. In this study we aimed to characterize whether the renal protection of FIN is related to a decrease in kidney damage through histomorphological changes in diabetic MWF rats. Design and method: Diabetes was induced by a streptozotocin injection (15 mg/Kg, i.p.) together with exposure to a high fat/high sucrose (HF/HS) diet (MWF-D) for 6 weeks. The MWF-D-FIN group was additionally treated with 10 mg/Kg/day of FIN included in the HF/HS diet (n = 6/group). Morphometrical analysis of renal structural changes was performed under hematoxylin and eosin staining, and light microscopy. Matrix metalloproteinases (MMP)-2 and MMP-9 activities were determined by zymography. Results: MWF-D and MWF-D-EP rats exhibited significantly elevated glycemia, water intake, urine volume, glucosuria, and kidney weight compared to control MWF. Histological examination of kidney samples of MWF and MWF-D rats showed hypertrophic glomeruli with an increase of the glomerular tuft and the Bowman's space. These pathological alterations were prevented by FIN treatment. The percentage of glomerulosclerosis was significantly higher in MWF and MWF-D rats and 59% lower in the MWF-D-FIN group (p<0.001) whereas the glomerulosclerosis index was reduced to 33% by FIN (p<0.001). Moreover, MWF-D rats showed an increased interstitial inflammation index compared to MWF rats (p<0.001) which was reduced to 44% (p<0.001) in the MWF-D-FIN group. Since an increase in MMP-2 and MMP-9 activities are associated with fibrosis development, these were determined by zymography in kidney samples of all groups. Both MMP-2 and MMP-9 were significantly higher in MWF-D compared to MWF and decreased by FIN treatment. Conclusions: In conclusion FIN prevents the development of diabetic kidney damage due to a reduction in glomerular alterations and interstitial inflammation associated to an inhibition of MMP-2 and MMP-9 activities.

SerpinA3N in Leptin Receptor Neurons Regulates Metabolic and Glucose Homeostasis

Obesity and associated conditions such as type 2 diabetes are among the most concerning issues for health in the U.S. Leptin receptor signaling in the brain plays a pivotal role in the regulation of food intake and energy expenditure. High fat diet induces inflammation within the hypothalamus, leading to leptin insensitivity which contribute to obesity. Previous studies have shown that a novel gene SerpinA3N, a serine protease inhibitor, which is highly expressed in the arcuate nucleus of the hypothalamus, where the leptin receptor is also highly expressed, is upregulated in diet-induced obesity and by leptin stimulation. However, the role of SerpinA3N in the leptin receptor expressing cells in the control of body weight and glucose homeostasis remain unknown. RNAseq analysis showed that SerpinA3N mRNA levels were significantly upregulated in the hypothalamus of mice fed high fat high sucrose diet (HFHSD) for 12 weeks. Upregulation of hypothalamic SerpinA3N in HFHSD fed mice was confirmed by Western blot. This increase in hypothalamic SerpinA3N appears to be caused by excess of nutrient as we found that exposure to fatty acid significantly increased SerpeinA3N promoter activity in mouse hypothalamic N39 cells. Using immunofluorescence staining, we confirmed that SerpinA3N is expressed the leptin receptor positive cells of the hypothalamus. Next, we investigated whether loss of SerpinA3N in leptin receptor expressing neurons affects metabolic and glucose homeostasis. For this, we crossed mice harboring floxed alleles of the SerpinA3N gene (SerpinA3Nfl/fl) with mice expressing Cre recombinase in leptin receptor cells (LepRCre). We found that female, but not male, conditional knockout (CKO, LepRCre/SerpinA3Nfl/fl) mice have significantly lower body weight when fed normal chow or HFHSD. This lower body weight was due to decreased fat mass, measured by NMR. However, no alteration in food intake was observed between female CKO mice and controls, indicating that increased energy expenditure may account for the lower body weight in female CKO mice. Interestingly, CKO mice displayed exaggerated weight loss and anorectic response following leptin treatment (1 mg/g, twice daily, IP), indicating that loss of SerpinA3N enhances leptin sensitivity. Female CKO mice fed normal chow diet also exhibited enhanced insulin sensitivity compared to control animals. On the other hand, male CKO mice displayed significantly improved glucose handling, but not change in insulin sensitivity, only when fed HFHSD. Finally, insulin-induced phosphorylation of AKT was elevated in skeletal muscle, but not in liver and white adipose tissue, of CKO mice relative to controls. These results demonstrate that SerpinA3N in leptin receptor-expressing neurons regulate body weight and glucose homeostasis in a sex-dependent manner. NIH and VA. This is the full abstract presented at the American Physiology Summit 2024 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.

Mitochondrial AKAP1 Is Necessary for Obesity- and Angiotensin II-induced Hypertension

Best known as the powerhouse of the cell, mitochondria play a crucial role in obesity and associated cardiovascular diseases. A-kinase anchoring protein 1 (AKAP1) is a mitochondrial scaffold protein that regulates mitochondria function by promoting protein kinase A (PKA)-mediated phosphorylation of Dynamin-related protein 1 at Ser637 through recruitment of PKA to the outer mitochondrial membrane. However, the role of mitochondrial AKAP1 in the regulation of blood pressure and the development of hypertension is not known. Here, we used mice harboring the Akap1 gene deletion to investigate the importance of AKAP1 in obesity- and angiotensin II (Ang II)-induced hypertension. AKAP1−/− mice and wild type (WT) littermates were maintained on a high fat high sucrose diet (HFHSD) for 12 weeks starting from 4 weeks of age. Interestingly, AKAP1−/− mice fed HFHSD displayed significantly attenuated weight gain compared to control mice fed HFHSD (male: 39.5 ± 1.7 vs 47.3 ± 2.3 g, and female: 29.7 ± 1.3 vs 32.5 ± 1.5 g, p<0.05 for both). This was associated with decreased fat mass in AKAP1−/− mice-fed HFHSD (male:16.2 ± 0.9 g and female: 8.7 ± 1.1 g) compared to controls (male: 21.2 ± 1.7 g and female: 13.9 ± 1.6 g, p<0.05 for both). Transmission electron microscope analysis of neuronal mitochondrial in the accurate nucleus of the hypothalamus showed that AKAP1−/− mice fed HFHSD have remarkably reduced mitochondria size (0.14 ± 0.05 vs 0.20 ± 0.07 μm2, p<0.05) and mitochondria length (0.57 ± 0.10 vs 0.50 ± 0.10 μm, p<0.05) relative to controls. Next, using the radio-telemetry system, we found that blood pressure was lower in AKAP1−/− male mice fed HFHSD compared to WT mice fed HFHSD (systolic: 118.2 ± 3.2 mmHg vs 126.7 ± 4.3 mmHg, p = 0.05, n= 5WT and 6 AKAP1−/−). Furthermore, infusion of Ang II (600ng/kg/min for 14 days) via osmotic minipumps in normal chow-fed male mice tended to evoke less increase in mean blood pressure in AKAP1−/− mice compared to WT controls (35.2 ± 3.5 vs 45.7 ± 10.1 mmHg, n=3). Taken together, our findings point to the importance of mitochondrial AKAP1 for the development of hypertension induced by obesity and Ang II. Veterans Affairs NIH. This is the full abstract presented at the American Physiology Summit 2024 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.

Abstract 3042: Oxidized Phospholipids Inhibit Glycolysis In Cardiomyocytes And Decrease Oxidative Phosphorylation By Activating The Mitogen-activated Protein Kinase Pathway

Oxidized phospholipids (oxPLs) were shown to be key players in the progression of numerous cardiovascular diseases including myocardial infarction, atherosclerosis, or cardiac ischemia reperfusion injury. However, the oxidized phospholipid-induced signaling mechanisms causing cardiac dysfunction remain elusive. We tested the hypothesis that oxPLs impact metabolism in cardiomyocytes and explored the involved signaling pathways. In vitro, treatment of h9c2 cardiomyocytes with a mixture of oxidized phosphatidylcholines (oxPAPC) led to activation of a mitogen-activated protein kinase (MAPK) pathway, namely phosphorylation of extracellular signal-regulated kinase 1/2 (ERK 1/2). Moreover, oxPAPC induced the expression of regulatory enzymes associated with the pentose phosphate pathway (PPP), such as PGD, G6PD, TALDO1, as well as genes connected to Nrf2-dependent oxidative stress, like HMOX-1. Metabolically, oxPAPC significantly reduced basal respiration and maximal oxygen consumption rate, as well as glycolytic capacity in h9c2 cardiomyocytes, as measured using a Seahorse extracellular flux analyzer. Treatment with a MEK inhibitor (PD98059, 10μM) resulted in a partial rescue of basal respiration and maximal oxygen consumption rate after incubation with oxPAPC. On the other hand, p38 inhibition (SB203580, 10μM) resulted in a change of oxPAPC-induced gene expression of PPP regulatory enzymes and HMOX-1. Ongoing studies including RNA-sequencing and pathway analysis will further explicate the scope of oxPL-induced gene expression and the involved mechanisms. In vivo , AAV8-mediated expression of the oxPL-recognizing scFv-E06 in albumin cre mice that had been fed a high fat high sucrose diet for 12 weeks, resulted in decreased expression of genes associated with GO Terms “glutathione metabolism” compared to AAV-GFP expressing counterparts, in their hearts. In summary, our study provides evidence that oxPLs significantly influence cardiomyocyte metabolism towards a redox-regulatory phenotype accompanied by the inhibited glycolysis and the decrease in oxidative phosphorylation by activating MAPK pathways. Future experiments will elucidate the relationship between MAPK signaling induced by oxPLs and cardiac dysfunction.

Proteomic profiling points to the significance of adipocyte-derived extracellular vesicles in diet-induced obesity

Extracellular vesicles (EVs) are lipid-bilayer membrane-enclosed vesicles well known to mediate cell-cell communication to maintain normal physiological functions. The diverse cargo of EVs encompassing proteins, lipids and miRNAs represent potential biomarkers and therapeutic targets. However, the role of adipocyte-derived EVs (AdEVs) in obesity is still unknown. To address this, we performed proteomic profiling of AdEVs isolated from the C57BL/6 male mice that were fed either a normal chow diet (NCD) or a high-fat high-sucrose diet (HFHSD) for 12 weeks starting at 4 weeks of age. AdEVs were obtained, through ultracentrifugation, from the conditioned media of cultured adipocytes derived from gonadal adipose tissue. Nanoparticle tracking analysis (NTA) of AdEVs showed that adipocytes from mice fed HFHSD tended to release more AdEVs despite the comparable size of AdEVs relative to those of mice fed NCD. Subsequently, proteins were isolated, digested and labeled with TMTpro16-plex for proteomic analysis. Raw data were processed in Scaffold, and a general bioinformatic and functional analysis conducted in Ingenuity Pathway Analysis Qiagen (IPA) ( https://digitalinsights.qiagen.com/explore/ga-ipa?utm_source=QDI_GA_SA_IPA_1122_PF&cmpid=QDI_GA_IPA ) and Srplot identified over 1100 proteins in AdEVs (protein threshold: 99%, minim peptide:2, peptide threshold: 95%, 0.00% FDR). Of these, 58 proteins were identified as upregulated while 41 proteins were downregulated in HFHSD-fed mice (Fold Change > 2, adjusted p < 0.05). With IPA analysis, the top 3 influenced pathways including mitochondrial dysfunction (27%), Sirtuin signaling pathway (22%), and Granzyme A signaling (38%) are predicted to be activated while the oxidative phosphorylation (47%), estrogen receptor signaling (15%) and neutrophil extracellular trap signaling pathway (14%) are predicted to be inhibited. The Gene Oncology (GO) functional enrichment analysis in Srplot revealed the involvement of identified differentially expressed proteins in various biological processes such as lipid metabolism, catabolic process processes, and cellular respiration. Experiments are underway to validate specific proteins involved in these biological processes. Furthermore, analysis of cellular components highlighted three notable terms including myelin sheath, collagen-containing extracellular matrix and organelle inner membrane. In conclusion, the present study elucidates the significance of AdEVs in the context of diet-induced obesity and underscores the potential role of mitochondrial dysfunction in the initiation and progression of obesity and its associated diseases. NIH Veterans Affairs. This is the full abstract presented at the American Physiology Summit 2024 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.

Voluntary Wheel Running Reduces Cardiometabolic Risks in Female Offspring Exposed to Lifelong High-Fat, High-Sucrose Diet.

Maternal and postnatal overnutrition has been linked to an increased risk of cardiometabolic diseases in offspring. This study investigated the impact of adult-onset voluntary wheel running to counteract cardiometabolic risks in female offspring exposed to a life-long high-fat, high-sucrose (HFHS) diet. Dams were fed either an HFHS or a low-fat, low-sucrose (LFLS) diet starting from 8 wk before pregnancy and continuing throughout gestation and lactation. Offspring followed their mothers' diets. At 15 wk of age, they were divided into sedentary (Sed) or voluntary wheel running (Ex) groups, resulting in four groups: LFLS/Sed ( n = 10), LFLS/Ex ( n = 5), HFHS/Sed ( n = 6), HFHS/Ex ( n = 5). Cardiac function was assessed at 25 wk, with tissue collection at 26 wk for mitochondrial respiratory function and protein analysis. Data were analyzed using two-way ANOVA. Although maternal HFHS diet did not affect the offspring's body weight at weaning, continuous HFHS feeding postweaning resulted in increased body weight and adiposity, irrespective of the exercise regimen. HFHS/Sed offspring showed increased left ventricular wall thickness and elevated expression of enzymes involved in fatty acid transport (CD36, FABP3), lipogenesis (DGAT), glucose transport (GLUT4), oxidative stress (protein carbonyls, nitrotyrosine), and early senescence markers (p16, p21). Their cardiac mitochondria displayed lower oxidative phosphorylation (OXPHOS) efficiency and reduced expression of OXPHOS complexes and fatty acid metabolism enzymes (ACSL5, CPT1B). However, HFHS/Ex offspring mitigated these effects, aligning more with LFLS/Sed offspring. Adult-onset voluntary wheel running effectively counteracts the detrimental cardiac effects of a lifelong HFHS diet, improving mitochondrial efficiency, reducing oxidative stress, and preventing early senescence. This underscores the significant role of physical activity in mitigating diet-induced cardiometabolic risks.

The Notch-PDGFRβ axis suppresses brown adipocyte progenitor differentiation in early post-natal mice

De novo brown adipogenesis holds potential in combating the epidemics of obesity and diabetes. However, the identity of brown adipocyte progenitor cells (APCs) and their regulation have not been extensively explored. Here, through invivo lineage tracing and mouse modeling, we observed that platelet-derived growth factor receptor beta (PDGFRβ)+ pericytes give rise to developmental brown adipocytes but not to those in adult homeostasis. By contrast, T-box 18 (TBX18)+ pericytes contribute to brown adipogenesis throughout both developmental and adult stages, though in a depot-specific manner. Mechanistically, Notch inhibition in PDGFRβ+ pericytes promotes brown adipogenesis by downregulating PDGFRβ. Furthermore, inhibition of Notch signaling in PDGFRβ+ pericytes mitigates high-fat, high-sucrose (HFHS)-induced glucose and metabolic impairment in mice during their development and juvenile phases. Collectively, these findings show that the Notch/PDGFRβ axis negatively regulates developmental brown adipogenesis, and its repression promotes brown adipose tissue expansion and improves metabolic health.

A Cross-Sectional Quantitative Metabolomics Study Evidencing the Metabolic Signature in Six Organs during a 14-Week High-Fat High-Sucrose and Standard Diet in Mice.

Obesity is a risk factor for many diseases, such as type 2 diabetes and cardiovascular diseases. In line with the need for precision medicine, the search for biomarkers reporting the progression of obesity- and diet-associated disorders is urgent. We used NMR to determine the metabolomics profile of key organs (lung, liver, heart, skeletal muscle, kidney, and brain) and serum from male C57Bl/6J mice (5 weeks old) fed for 6, 10, and 14 weeks on a high-fat and high-sucrose diet (HFHSD) vs. a standard diet (STD). We determined metabolite concentrations in the organs at each time point, which allowed us to discriminate age- and diet-related effects as well as the interactions between both, highlighting the need to evaluate the influence of age as a confounding factor on metabolic signatures. Notably, the analysis revealed the influence of time on metabolite concentrations in the STD condition, probably reflecting the juvenile-to-adult transition. Variations impacted the liver and lung metabolites, revealing the strong influence of the HFHS diet on normal metabolism maturation during youth.

ACAD10 is not required for metformin's metabolic actions or for maintenance of whole-body metabolism in C57BL/6J mice.

Acyl-coenzyme A dehydrogenase family member 10 (ACAD10) is a mitochondrial protein purported to be involved in the fatty acid oxidation pathway. Metformin is the most prescribed therapy for type 2 diabetes; however, its precise mechanisms of action(s) are still being uncovered. Upregulation of ACAD10 is a requirement for metformin's ability to inhibit growth in cancer cells and extend lifespan in Caenorhabditis elegans. However, it is unknown whether ACAD10 plays a role in metformin's metabolic actions. We assessed the role for ACAD10 on whole-body metabolism and metformin action by generating ACAD10KO mice on a C57BL/6J background via CRISPR-Cas9 technology. In-depth metabolic phenotyping was conducted in both sexes on a normal chow and high fat-high sucrose diet. Compared with wildtype mice, we detected no difference in body composition, energy expenditure or glucose tolerance in male or female ACAD10KO mice, on a chow diet or high-fat, high-sucrose diet (p ≥ .05). Hepatic mitochondrial function and insulin signalling was not different between genotypes under basal or insulin-stimulated conditions (p ≥ .05). Glucose excursions following acute administration of metformin before a glucose tolerance test were not different between genotypes nor was body composition or energy expenditure altered after 4 weeks of daily metformin treatment (p ≥ .05). Despite the lack of a metabolic phenotype, liver lipidomic analysis suggests ACAD10 depletion influences the abundance of specific ceramide species containing very long chain fatty acids, while metformin treatment altered clusters of cholesterol ester, plasmalogen, phosphatidylcholine and ceramide species. Loss of ACAD10 does not alter whole-body metabolism or impact the acute or chronic metabolic actions of metformin in this model.

Taraxacum officinale Extracts Alleviate Anhedonia and Depression by Inhibiting UPRmt and Mitophagy in the Hippocampi of T2DM Rats

<i>Taraxacum officinale</i> Extracts Alleviate Anhedonia and Depression by Inhibiting UPR^mt and Mitophagy in the Hippocampi of T2DM Rats

Beneficial Effects of Dietary Flaxseed on Non-Alcoholic Fatty Liver Disease.

Non-alcoholic fatty liver disease (NAFLD), a significant cause of chronic liver disease, presents a considerable public health concern. Despite this, there is currently no treatment available. This study aimed to investigate dietary flaxseed in the JCR:LA-corpulent rat strain model of NAFLD. Both obese male and female rats were studied along with their lean counterparts after 12 weeks of ingestion of a control diet, or control diet with flaxseed, or high fat, high sucrose (HFHS), or HFHS plus flaxseed. Obese rats showed higher liver weight and increased levels of cholesterol, triglyceride, and saturated fatty acid, which were further elevated in rats on the HFHS diet. The HFHS diet induced a significant two-fold elevation in the plasma levels of both aspartate aminotransferase and alanine aminotransferase in the obese male and female rats. Including flaxseed in the HFHS diet significantly lowered liver weight, depressed the plasma levels of both enzymes in the obese male rats, and reduced hepatic cholesterol and triglyceride content as well as improving the fatty acid profile. In summary, including flaxseed in the diet of male and female obese rats led to an improved lipid composition in the liver and significantly reduced biomarkers of tissue injury despite consuming a HFHS chow.

Cross-sectional association between blood cholesterol and calcium levels in genetically diverse strains of mice.

Genetically diverse outbred mice allow for the study of genetic variation in the context of high dietary and environmental control. Using a machine learning approach, we investigated clinical and morphometric factors that associate with serum cholesterol levels in 840 genetically unique Diversity Outbred mice of both sexes (n = 417 male and 423 female), and on both acontrol chow (% kcals in diet: protein 22%, carbohydrate 62%, fat 16%,no cholesterol) and high fat high sucrose (%kcals in diet: protein 15%, carbohydrate 41%, fat 45%, 0.05% cholesterol). We find expected elevations of cholesterol in male mice, as well as in mice with elevated serum triglycerides and/or fed a high fat high sucrose diet. The third strongest predictor was serum calcium which correlated with serum cholesterol across both diets and sexes (r = 0.39-0.48) in both Diversity Outbred (P = 3.0 × 10-43 ) and BXD (P = 0.005) mice. This is in-line with several human cohort studies which show associations between calcium and cholesterol, and calcium as an independent predictor of cardiovascular events.

Western diet consumption by host vertebrate promotes altered gene expression on Aedes aegypti reducing its lifespan and increasing fertility following blood feeding

BackgroundThe high prevalence of metabolic syndrome in low- and middle-income countries is linked to an increase in Western diet consumption, characterized by a high intake of processed foods, which impacts the levels of blood sugar and lipids, hormones, and cytokines. Hematophagous insect vectors, such as the yellow fever mosquito Aedes aegypti, rely on blood meals for reproduction and development and are therefore exposed to the components of blood plasma. However, the impact of the alteration of blood composition due to malnutrition and metabolic conditions on mosquito biology remains understudied.MethodsIn this study, we investigated the impact of whole-blood alterations resulting from a Western-type diet on the biology of Ae. aegypti. We kept C57Bl6/J mice on a high-fat, high-sucrose (HFHS) diet for 20 weeks and followed biological parameters, including plasma insulin and lipid levels, insulin tolerance, and weight gain, to validate the development of metabolic syndrome. We further allowed Ae. aegypti mosquitoes to feed on mice and tracked how altered host blood composition modulated parameters of vector capacity.ResultsOur findings identified that HFHS-fed mice resulted in reduced mosquito longevity and increased fecundity upon mosquito feeding, which correlated with alteration in the gene expression profile of nutrient sensing and physiological and metabolic markers as studied up to several days after blood ingestion.ConclusionsOur study provides new insights into the overall effect of alterations of blood components on mosquito biology and its implications for the transmission of infectious diseases in conditions where the frequency of Western diet-induced metabolic syndromes is becoming more frequent. These findings highlight the importance of addressing metabolic health to further understand the spread of mosquito-borne illnesses in endemic areas.Graphical

Gestational Intermittent Hypoxia Impairs AT2R-Mediated Vascular Protection in Female Offspring on a High-Fat, High-Sucrose Diet.

Gestational intermittent hypoxia (GIH), a hallmark of maternal obstructive sleep apnea, sex-differentially causes hypertension and endothelial dysfunction in adult male offspring but not in females. This study investigated whether the GIH-exposed female offspring, a "protected" group against the hypertensive effects of maternal GIH exposure, exhibit increased susceptibility to hypertension and cardiovascular dysfunction when fed a high-fat high-sucrose (HFHS) diet and whether this effect could be reversed by pharmacological intervention activating the angiotensin II type 2 receptor (AT2R). Female offspring of control and GIH-exposed (10.5% O2, 8 h/d, E10-21) dams were assigned either an HFHS diet or a standard diet from 12 weeks of age. Blood pressure was monitored. At 28 weeks, a systemic CGP42112 (AT2R agonist) or saline infusion was administered through the osmotic pump. At 30 weeks, the heart was weighed and collected for H&E staining, mesenteric arteries for vascular reactivity assessment and protein analysis, and plasma for ELISA. The HFHS diet induced similar increases in body weight gain and blood pressure in control and GIH female offspring. HFHS feeding did not affect heart structure, but impaired endothelial-dependent vascular relaxation with associated decreased AT2R and eNOS expression and reduced plasma bradykinin levels in both control and GIH offspring. CGP42112 administration effectively mitigated HFHS-induced hypertension and endothelial dysfunction only in control offspring, accompanied by restored AT2R, eNOS, and bradykinin levels, but not in the GIH counterparts. These findings suggest that GIH induces endothelial dysfunction and AT2R insensitivity in female offspring exposed to an HFHS diet.

Diethylnitrosamine-Induced Liver Tumorigenesis in Mice Under High-Hat High-Sucrose Diet: Stepwise High-Resolution Ultrasound Imaging and Histopathological Correlations.

The hepatotoxic N-nitroso compound diethylnitrosamine (DEN) administered intraperitoneally (i.p.) induces liver neoplasms in rodents that reproducibly recapitulate some aspects of human hepatocarcinogenesis. In particular, DEN drives the stepwise formation of pre-neoplastic and neoplastic (benign or malignant) hepatocellular lesions reminiscent of the initiation-promotion-progression sequence typical of chemical carcinogenesis. In humans, the development of hepatocellular carcinoma (HCC) is also a multi-step process triggered by continuous hepatocellular injury, chronic inflammation, and compensatory hyperplasia that fuel the emergence of dysplastic liver lesions followed by the formation of early HCC. The DEN-induced liver tumorigenesis model represents a versatile preclinical tool that enables the study of many tumor development modifiers (genetic background, gene knockout or overexpression, diets, pollutants, or drugs) with a thorough follow-up of the multistage process on live animals by means of high-resolution imaging. Here, we provide a comprehensive protocol for the induction of hepatocellular neoplasms in wild-type C57BL/6J male mice following i.p. DEN injection (25mg/kg) at 14days of age and 36weeks feeding of a high-fat high-sucrose (HFHS) diet. We emphasize the use of ultrasound liver imaging to follow tumor development and provide histopathological correlations. We also discuss the extrinsic and intrinsic factors known to modify the course of liver tumorigenesis in this model.

Portosystemic shunting prevents hepatocellular carcinoma in non-alcoholic fatty liver disease mouse models.

Non-alcoholic fatty liver disease (NAFLD) is one of the leading cause of hepatocellular carcinoma (HCC). This association is supported by the translocation of bacteria products into the portal system, which acts on the liver through the gut-liver axis. We hypothesize that portosystemic shunting can disrupt this relationship, and prevent NAFLD-associated HCC. HCC carcinogenesis was tested in C57BL/6 mice fed a high-fat high-sucrose diet (HFD) and injected with diethylnitrosamine (DEN) at two weeks of age, and in double transgenic LAP-tTA and TRE-MYC (LAP-Myc) mice fed a methionine-choline-deficient diet. Portosystemic shunts were established by transposing the spleen to the sub-cutaneous tissue at eight weeks of age. Spleen transposition led to a consistent deviation of part of the portal flow and a significant decrease in portal pressure. It was associated with a decrease in the number of HCC in both models. This effect was supported by the presence of less severe liver steatosis after 40 weeks, and lower expression levels of liver fatty acid synthase. Also, shunted mice exhibited lower liver oxygen levels, a key factor in preventing HCC as confirmed by the development of less HCCs in mice with hepatic artery ligation. The present data show that portosystemic shunting prevents NAFLD-associated HCC, utilizing two independent mouse models. This effect is supported by the development of less steatosis, and a restored liver oxygen level. Portal pressure modulation and shunting deserve further exploration as potential prevention/treatment options for NAFLD and HCC.

Exposure to early-life stress impairs weight-loss maintenance success in mice.

The impact of early-life stress on weight-loss maintenance is unknown. Mice underwent neonatal maternal separation (NMS) from 0 to 3 weeks and were weaned onto a high-fat sucrose diet (HFSD) from 3 to 20 weeks. Calorie-restricted weight loss on a low-fat sucrose diet (LFSD) occurred over 2 weeks to induce a 20% loss in body weight, which was maintained for 6 weeks. After weight loss, half of the mice received running wheels, and the other half remained sedentary. Mice were then fed ad libitum on an HFSD or LFSD for 10 weeks and were allowed to regain body weight. NMS mice had greater weight regain, total body weight, and adiposity compared with naïve mice. During the first week of refeeding, NMS mice had increased food intake and were in a greater positive energy balance than naïve mice. Female mice were more susceptible to NMS-induced effects, including increases in adiposity. NMS and naïve females were more susceptible to HFSD-induced weight regain. Exercise was beneficial in the first week of regain in male mice, but, long-term, only those on the LFSD benefited from exercise. As expected, HFSD led to greater weight regain than LFSD. Early-life stress increases weight regain in mice.

High Fat Diet and High Sucrose Intake Divergently Induce Dysregulation of Glucose Homeostasis through Distinct Gut Microbiota-Derived Bile Acid Metabolism in Mice.

A high calorie diet such as excessive fat and sucrose intake is always accompanied by impaired glucose homeostasis such as T2DM (type 2 diabetes mellitus). However, it remains unclear how fat and sucrose individually affect host glucose metabolism. In this study, mice were fed with high fat diet (HFD) or 30% sucrose in drinking water (HSD) for 24 weeks, and glucose metabolism, gut microbiota composition, as well as bile acid (BA) profile were investigated. In addition, the functional changes of HFD or HSD-induced gut microbiota were further verified by fecal microbiota transplantation (FMT) and ex vivo culture of gut bacteria with BAs. Our results showed that both HFD and HSD caused dysregulated lipid metabolism, while HFD feeding had a more severe effect on impaired glucose homeostasis, accompanied by reduced hyocholic acid (HCA) levels in all studied tissues. Meanwhile, HFD had a more dramatic influence on composition and function of gut microbiota based on α diversity indices, β diversity analysis, as well as the abundance of secondary BA producers than HSD. In addition, the phenotypes of impaired glucose homeostasis and less formation of HCA caused by HFD can be transferred to recipient mice by FMT. Ex vivo culture with gut bacteria and BAs revealed HFD-altered gut bacteria produced less HCA than HSD, which might closely associate with reduced relative abundance of C7 epimerase-coding bacteria g_norank/unclassified_f_Eggerthellaceae and bile salt hydrolase-producing bacteria Lactobacillus and Bifidobacterium in HFD group. Our findings revealed that the divergent effects of different high-calorie diets on glucose metabolism may be due to the gut microbiota-mediated generation and metabolism of BAs, highlighting the importance of dietary management in T2DM.