Intraperitoneal Glucose Research Articles

Effects of diallyl disulfide administration on insulin resistance in high-fat diet-fed mice

ObjectivesDiallyl disulfide (DADS) is a natural organosulfur compound found in garlic and related plants with various pharmacologic effects. However, whether DADS improves obesity-induced insulin resistance (IR) and its underlying mechanisms remain unclear. The aim of this study was to investigate the effects of DADS on systemic IR in high-fat diet-induced obese mice. MethodsTo induce obesity, 8-wk-old male C57BL/6J mice were fed a high-fat diet (60% fat/kcal). The mice were assigned to three weight-matched groups: control (CON, n = 8), low-dose DADS (DADS-L, n = 8), and high-dose DADS (DADS-H, n = 9). The treated mice were orally administered DADS (25 or 100 mg/kg) 5 d/wk for 8 wk. At 15 wk of age, an intraperitoneal glucose tolerance test (GTT) and insulin tolerance test (ITT) were performed. Twenty-four hours after the final administration of DADS, epididymal fat and the liver were sampled after a 5-h fast. ResultsDADS administration significantly attenuated body and fat weight gains during the experimental period. Additionally, systemic IR, as evaluated by ITT, was significantly improved by DADS administration in a dose-dependent manner. High-dose DADS administration significantly decreased liver triacylglycerol levels. Moreover, high-dose DADS administration decreased the c-Jun N-terminal kinase (JNK) phosphorylation and significantly increased heat shock protein 72 expression in the liver. ConclusionsThe results of this study suggested that DADS administration alleviated systemic IR in obese mice. This may be associated with decreased hepatic fat accumulation and a heat shock protein 72-mediated decrease in JNK activity in the liver.

Dapagliflozin treatment and cardiovascular outcome in RBP4/TTRVal30Met (transthyretin cardiac amyloidosis) mice.

Whether sodium-glucose co-transporter 2 inhibitors are effective for heart failure caused by ATTR-CA (transthyretin cardiac amyloidosis) remains uncertain. The aim of this study is to investigate the cardiovascular prognosis in ATTR-CA mice model with dapagliflozin treatment. Humanized RBP4/TTRVal50Met and RBP4/TTR mice models were constructed with clustered regularly interspaced short palindromic repeats and associated Cas9 endonuclease (CRISPR-Cas9) techniques and multiple generations breeding. A total of 6 RBP4/TTR mice received placebo treatment, when 12 RBP4/TTRVal50Met received dapagliflozin (1mg/kg/day, 6 mice) and placebo (6 mice) treatment. Fasting glucose, intraperitoneal glucose tolerance test, and plasma brain natriuretic peptide (BNP) concentration were measured at Day 0, Week 2, and Week 4. BNP, transforming growth factor-beta (TGF-β), collagen type I alpha 1 (COL1A1) protein levels, and Cola1, TGFβ1, TNFα, IL-1β, BNP relative quantities in cardiac, along with cardiac pathology examination including right ventricular collagen percentage, ventricular septum thickness, left ventricular wall thickness, and left ventricular internal diameter were measured at Week 4 after treatment procedure. All 18 mice completed the experiment. The baseline characteristics were balanced among three treatment groups. In placebo-treated mice, the cardiac BNP relative quantity was significantly higher in RBP4/TTRVal50Met mice than RBP4/TTR mice (RBP4[KI/KI], TTR [KI/KI]: 0.72±0.46, RBP4[KI/KI], TTRVal50Met [KI/KI]: 1.44±0.60, P=0.043), indicating more significant heart failure progression in ATTR-CA mice than normal mice. In ATTR-CA mice, the cardiovascular prognosis measurements including heart failure (plasma BNP concentration and relative quantities of BNP), cardiac inflammation (relative quantities of Cola1, TGFβ1, TNFα, and IL-1β), and pathological changes (right ventricular collagen percentage, ventricular septum thickness, left ventricular wall thickness, and left ventricular internal diameter) were statistically comparable between those under dapagliflozin and placebo treatment. Dapagliflozin did not improve cardiovascular prognosis including the progression of heart failure, cardiac inflammation, and pathological changes in ATTR-CA mice compared with placebo. The results of this study were not in support of dapagliflozin's therapeutic effects for ATTR-CA. More pre-clinical and clinical researches to validate these findings and demonstrate the underlying mechanisms are still required.

Administration of Akebia Saponin D Improved Blood Lipid Levels and Pregnancy Outcomes in Mice with Gestational Diabetes Mellitus

Gestational diabetes mellitus (GDM) is a prevalent and severe metabolic disease in pregnant women that is characterized by a high incidence. Placental oxidative stress and inflammation are recognized as the primary contributors to GDM pathogenesis. The repressive effect of akebia saponin D (ASD) on oxidative stress and inflammation has been demonstrated in various diseases. To investigate the impact of ASD on GDM. Animal experimental study. GDM mice were intraperitoneally treated with ASD. The effect of ASD on GDM symptoms, blood lipid levels, pancreatic tissue damage, gestational outcomes, oxidative stress, and inflammation was assessed via intraperitoneal glucose and insulin tolerance tests, serum glucose and insulin level determination, lipid biochemistry analysis, pathological staining, oxidative stress evaluation, western blot analysis, and enzyme-linked immunosorbent assay. ASD reduced the GDM-induced increase in body weight and blood glucose levels while restoring the decreased insulin levels associated with GDM. In addition, ASD improved the serum lipid parameters, pancreatic tissue damage, and gestational outcomes in GDM mice. Furthermore, ASD reversed the decreased levels of superoxide dismutase and glutathione while reducing the elevated concentrations of malondialdehyde and myeloperoxidase in GDM mice. In addition, ASD rescued the relative protein expression of nuclear factor-E2-related factor 2 and heme oxygenase-1 in the placenta of GDM mice. Additionally, ASD counteracted the increase in tumor necrosis factor-α, interleukin (IL)-6, and IL-1β levels in the sera and placenta of GDM mice. ASD suppressed oxidative stress and inflammation to effectively relieve symptoms and gestational outcomes of the GDM mice.

OR10-02 Effect Of Phosphodiesterase 4 Inhibitors On Weight Loss And Energy Homeostasis In Mice With Obesity Induced By A High-fat-diet

Abstract Disclosure: M.A. de Andrade: None. H. da Silva: None. A.A. Jesus: None. F.J. de Paula: None. L. Elias: None. INTRODUCTION: Obesity is a worldwide health problem and the incidence of associated diseases such as type 2 diabetes is increasing. Leptin (Lep) resistance arises from obesity-related inflammation, enhancing the appetite. The expression of phosphodiesterase 4 enzymes (PDE4) is increased in inflammatory conditions. Rolipram (Rol) acts to inhibit PDE4 reducing adiposity and peripheral inflammation. Notwithstanding, the effects of Rol on Lep sensitivity and energy balance are still unknown. Objective: To evaluate the effect of PDE4 inhibition on energy homeostasis and Lep sensitivity and glucose tolerance in mice with obesity induced by a high-fat diet (HFD). Methodology: Four-week-old male C57BL6 mice were fed a HFD (60%, Research Diets) or chow diet (C) for 10 weeks. In the 8th week, they received daily subcutaneous Rol injections (2mg/kg) or vehicle (V) and food intake and body weight were daily measured. Energy expenditure (EE) was measured on the 8th day of treatment using a metabolic cage (Oxymax). After treatment, mice underwent 6h fasting and subsequent intraperitoneal (i.p.) glucose injection (2g/kg). Fasting blood glucose (FG) and 120 minutes after glucose (GTT) were measured. On the last day of treatment, 90 minutes after the Rol or V injection, i.p. Lep (5mg/kg in 100ul) or saline (S) was injected, and weight and food intake were measured 14 and 24h later. Results: 5-10 mice were analyzed in each group (chow + V, CV; chow + Rol, CR; HFD + V, HV; HFD + Rol, HR). There was a significant difference in body weight between HR and HV: absolute weight (HR 35+-4.18; HV 38.8+-3.88g; p 0.038) and weight variation (HR -2.26+-0.99; HV -0.19+-1.25g; p 0.002), but no difference between CR and CV (27.98+-2.25; 26.8 +- 2.22g, p 0.97). Rol effectively reduced ingestion in both diets (CR 42.85+-2.7; CV 48.13+-4.51g; p 0.03) (HR 24.75+-2.44; HV 28.31 +-2.81g; p 0.01). In the HFD groups, compared to V, Rol increased VO2 (p 0.04) and energy expenditure (p 0.049) as well as the heat (p 0.03). There was no difference in VCO2 nor motor activity. Lep sensitivity was evaluated in the HFD group and there was a significant reduction in food intake 24h after the Lep application compared to S (Lep 2.18+-0.2; S 2.47+-0.18g, p 0.04). There was no difference in food intake 14h after Lep or weight after injection at either time point (14/24h). Rol was ineffective to improve FG/GTT in the HFD group. Conclusion: Rolipram, a PDE4 inhibitor, effectively reduces the body weight of diet-induced obesity by reducing food intake, increasing basal energy expenditure and improving leptin sensitivity. PDE4 appears as a potential target to treat obesity. Presentation: Friday, June 16, 2023

SAT035 Oligonucleotide IMT504 Markedly Improves Metabolic Sindrome And Type 2 Diabetes In High-Fat Diet Fed Mice

Abstract Disclosure: L. Domé: None. J.M. Riaño Gomez: None. M.M. Bonaventura: None. M.O. Fernandez: None. A.D. Montaner: None. V.A. Lux-Lantos: None. M.S. Bianchi: None. We have shown that the immunomodulatory oligonucleotide IMT504 (IMT) improves glucose homeostasis in several animal models of type 1 diabetes by regulating immunomodulatory factors and by improving beta-cell function. Here we evaluated the effects of IMT in a murine model of metabolic syndrome and type 2 diabetes induced by high-fat diet (HFD).Five weeks-old C57BL/6LP male mice were fed either standard diet (SD) or HFD (ResearchDiet, D12492) for 12 weeks. HFD mice showed higher non-fasting glycemia (NF-Gly: p<0.01), and body weight (BW: p<0.01). Thereafter, mice received one daily dose of IMT504 for 12 consecutive days [IMT(mg/kg/day), subcutaneous: 20, 6 or 2, only HFD mice) or saline (SD and HFD). Intraperitoneal glucose tolerance test (ipGTT, day 10), insulin secretion test (IST, day 10) and insulin tolerance test (ITT, day 11) were performed. On day 12, food intake (days 1-12), BW, and non-fasting Gly, were recorded; after 3 hours fasting, Gly were recorded, mice were sacrificed, and blood samples collected. Serum insulin levels were analyzed by ELISA.Food (F) and calories (C) consumed decreased with IMT treatment [F(g): ANOVA, p<0.001; HFD different from IMT6 and IMT20: p<0.05], [C (Kcal): ANOVA, p<0.001; HFD different from SD, IMT6, and IMT20: p<0.05]; BW also decreased [repeated measures ANOVA: interaction, p<0.05; SD: different from all on both days, p<0.01; IMT6: Day1 vs Day12, p<0.01; IMT20: Day1 vs Day12, p<0.002]. NF-Gly did not vary with time in SD and HFD mice (day 12 vs day 1), while it significantly diminished with IMT [NF-Gly (mg/dl): repeated measures ANOVA: interaction, p<0.05; IMT6: Day1 vs Day12, p<0.02; IMT20: Day1 vs Day12, p<0.02]. IMT also induced a significant recovery of glucose clearance [GTT-AUC: ANOVA, p<0.01; HFD different from SD, IMT6, and IMT20: p<0.01], as well as of insulin secretion in response to the glucose overload [IST-AUC: ANOVA: p<0.05; HFD different from SD, IMT6, and IMT20: p<0.05] and peripheral response to insulin [ITT- AUC: ANOVA, p<0.01; HFD different from SD, HFD, IMT6, and IMT20: p<0.01]. In addition, IMT decreased the higher Gly and insulinemia (Ins) present in fasting HFD mice [Gly: ANOVA: p<0.001; HFD different from SD, IMT6, and IMT20: p<0.005], [Ins (ng/mL): ANOVA p<0.05; SD vs HFD: p<0.06; HFD different from IMT6, and IMT20: p<0.05]. These effects were consistent with amelioration of peripheral insulin resistance [HOMA-IR index: ANOVA, p<0.006; HFD different from SD, IMT6, and IMT20: p<0.05], and insulin sensitivity [QUICKI: ANOVA, p<0.02; HFD different from SD and IMT20: p<0.05]. IMT treatment promotes a significant, dose-dependent, improvement in the diabetic condition and food intake in HFD mice. Further research is needed to understand its mechanism of action. Funding: CONICET, ANPCYT, Sidus Arg, F. R Barón, F. Williams. Presentation: Saturday, June 17, 2023

FRI107 Ketogenic Diet Prevents Development Of Atherosclerotic Plaques In Apolipoprotein E Knockout Mice

Abstract Disclosure: V. Marzolla: None. A. Armani: None. C. Mammi: None. S. Gorini: None. E. Camajani: None. M. Caprio: None. Higher aldosterone (aldo) levels are associated with increased risk of cardiovascular ischemic events and mortality. It has been demonstrated that aldo accelerates the development of atherosclerosis in apolipoprotein E knockout mice (ApoE KO). Ketogenic diet (KD) positively impacts several cardiovascular risk factors, yet its effect on atherosclerosis is elusive. We hypothesize that KD protects from development of atherosclerotic plaques in ApoE KO mice, a murine model of atherosclerosis. Eight-week-old male ApoE KO mice were fed a KD (90,5% Kcal from fat, 0.4% Kcal from carbohydrate, 9.1% Kcal from protein) or a moderate high fat die (HFD) (42% Kcal from fat, 42.7% Kcal from carbohydrate, 15.2% Kcal from protein) and treated with aldosterone (aldo, 6 μg/mouse per day) or vehicle through osmotic mini-pumps. Cholesterol content was comparable in KD and HFD. After 4 weeks of treatment, in all experimental groups, intraperitoneal glucose tolerance test was performed, and peripheral blood samples were collected. We analysed cryosections of embedded aortic root to quantify the atherosclerotic plaque size, lipid and collagen content. We assessed vascular inflammation in speciments of thoracic aorta by analysing pro-inflammatory (ICAM-1, VCAM-1, IL-6, TNF-α, MCP-1) and anti-inflammatory (Arg-1, RETNLA, CCL5) genes. In ApoE KO mice treated with aldo, KD determined a significant improvement in glucose tolerance, compared to mice fed a HFD, without any significant effect on body weight. Beta-hydroxybutyrate levels were always significantly higher in KD-mice than in AD-mice, confirming nutritional ketosis in KD-mice. Analysis of aortic root showed that aldo treatment determined a significant increase in atherosclerotic plaque size and lipid content in HFD-mice. Such effects were significantly reduced in KD-mice, suggesting a favorable impact of ketosis in preventing atherosclerosis development. Plaque fibrosis did not differ among treatment groups. Finally, we observed a significant reduction in vascular inflammatory markers in KD-mice, when compared to HFD-mice. In particular, KD determined a significant reduction in gene expression of pro-inflammatory markers (ICAM-1, VCAM-1, IL-6, TNF-α, MCP-1) with the concomitant up-regulation of anti-inflammatory markers (Arg-1, RETNLA, CCL5), compared to HFD. The study suggests KD as a potential non-pharmacological approach to prevent the development of atherosclerotic disease in subjects with high cardiovascular risk. Presentation: Friday, June 16, 2023

A-046 Investigating the Role of RNase L in Metabolic Syndrome

Abstract Background Metabolic syndrome is closely associated with the incidence of heart disease, type 2 diabetes, and stroke. Though the exact cause of metabolic syndrome is not known, many features of the metabolic syndrome are caused by insulin resistance. Recent years, accumulating evidence has shown that dysregulation of insulin signaling leads to insulin resistance. Interestingly, we have observed that RNase L affects the insulin signaling pathway by regulating the activation of insulin receptor subtrate-1 (IRS-1) in primary mouse embryonic fibroblasts (MEFs) and primary mouse hepatocyte. RNase L is an enzyme that plays a critical role in interferon function against viral infection and cellular proliferation. How RNase L affects the insulin signaling pathway is still unknown. Methods Age-matched C57BL/6 background RNase L wild type (WT) and knockout (KO) mice (n = 6–8) were fed on a chow diet. Metabolic tolerance tests including glucose tolerance test (GTT) and insulin tolerance test (ITT) were conducted on mice between 12 and 16 weeks old. Mice were subjected to either a morning (4 h) or an overnight (12 h) fast, then intraperitoneally injected with glucose (1.5 g/kg body weight) in PBS, pH 7.4, for GTT and insulin (1.0I U/kg body weight) for ITT. Blood was collected via tail vein at different time intervals over a span of 2 h and blood glucose was measured using a glucometer. Results We found that RNase L KO mice displayed significantly increased glucose tolerance in compared to RNase L WT mice as measured in the intraperitoneal glucose tolerance test. The glucose level in RNase L KO mice was 150% higher than that in RNase L WT mice after IP injection of glucose in 60 min. In the ITT experiment, the glucose level in RNase L KO mice was 130% higher than that in WT mice in 60 min post injection. Taken together, the results in GTT and ITT indicated that RNase L mediates the metabolism of glucose in vivo. Further investigation of molecular mechanisms is currently being conducted. Conclusion Our results suggests that RNase L plays a role in insulin sensitivity, which affects glucose metabolism.

Altered expression of long noncoding RNA MEG3 in the offspring of gestational diabetes mellitus induces impaired glucose tolerance in adulthood.

Gestational diabetes mellitus (GDM) affects a significant number of women worldwide and has been associated with lifelong health consequences for their offspring, including increased susceptibility to obesity, insulin resistance, and type II diabetes. Recent studies have suggested that aberrant expression of the long non-coding RNA Meg3 in the liver may contribute to impaired glucose metabolism in individuals. In this study, we aimed to investigate whether intrauterine exposure to hyperglycemia affects glucose intolerance in puberty by mediating the overexpression of LncMeg3 in the liver. To test our hypothesis, we established an animal model of intrauterine hyperglycemia to mimic GDM. The progeny was observed for phenotypic changes, and intraperitoneal glucose tolerance tests, insulin tolerance tests, and pyruvate tolerance tests were conducted to assess glucose and insulin tolerance. We also measured LncMeg3 expression in the liver using real-time quantitative PCR and examined differential methylation areas (DMRs) in the Meg3 gene using pyrophosphoric sequencing. To investigate the role of LncMeg3 in glucose tolerance, we conducted Meg3 intervention by vein tail and analyzed the changes in the phenotype and transcriptome of the progeny using bioinformatics analysis. We found that intrauterine exposure to hyperglycemia led to impaired glucose and insulin tolerance in the progeny, with a tendency toward increased fasting blood glucose in fat offspring at 16weeks (P = 0.0004). LncMeg3 expression was significantly upregulated (P = 0.0061), DNMT3B expression downregulated (P = 0.0226), and DNMT3A (P = 0.0026), TET2 (P = 0.0180) expression upregulated in the liver. Pyrophosphoric sequencing showed hypomethylation in Meg3-DMRs (P = 0.0005). Meg3 intervention by vein tail led to a decrease in the percentage of obese and emaciated offspring (emaciation: 44% vs. 23%; obesity: 25% vs. 15%) and attenuated glucose intolerance. Bioinformatics analysis revealed significant differences in the transcriptome of the progeny, particularly in circadian rhythm and PPAR signaling pathways. In conclusion, our study suggests that hypomethylation of Meg3-DMRs increases the expression of the imprinted gene Meg3 in the liver of males, which is associated with impaired glucose tolerance in GDM-F1. MEG3 interference may attenuate glucose intolerance, which may be related to transcriptional changes. Our findings provide new insights into the mechanisms underlying the long-term effects of intrauterine hyperglycemia on progeny health and highlight the potential of Meg3 as an intervention target for glucose intolerance.

Abstract 029: Hypertensive Disorder Of Pregnancy Results In Loss Of Pancreatic Beta Cell Area In Female Rat Offspring Without Development Of Glucose Intolerance

Hypertensive disorders of pregnancy can result in increased risk for type 2 diabetes (T2D) in offspring. Reduced pancreatic beta cell area can also influence development of glucose intolerance or T2D. Using a rat model of reduced uterine perfusion pressure (RUPP) which leads to hypertension during pregnancy and intrauterine growth restriction, we previously demonstrated reduced beta cell area in female RUPP offspring vs Sham at embryonic day 19 persisting to postnatal day (PD)13. To determine if this alteration in beta cell area is associated with phenotypic changes in glucose handling as offspring mature, we assessed IPGTT (intraperitoneal glucose tolerance test), OGTT (oral glucose tolerance test) and ITT (insulin tolerance test) in PD14, PD28, 8 week and 6 month female offspring (n=5-11/group). Our results demonstrate no change in fasting blood glucose and no alteration in glucose handling with IP glucose administration at any age. However, peak glucose following oral glucose administration was significantly less in RUPP offspring at PD14 (196.3+/-8.6 mg/dl, RUPP; 218.3+/-9.5 mg/dl, Sham; p=0.05), PD28 (220.0+/-4.1 mg/dl, RUPP; 280.0+/-12.8 mg/dl, Sham; p<0.05) and 6 months (139.6+/-3.8 mg/dl, RUPP; 150.9+/-4.5 mg/dl, Sham; p<0.05) compared to Sham, suggesting the incretin effect on pancreas and non-pancreas tissues is more effective in controlling blood glucose in RUPP offspring vs Sham. In addition, the decrease in glucose level in response to insulin injection in ITT was significantly greater in RUPP offspring vs Sham at PD28 (58.9+/-5.0 mg/dl, RUPP; 78.3+/-8.9 mg/dl, Sham; p<0.05) suggesting increased insulin sensitivity in non-pancreatic tissues in RUPP compared to Sham offspring. Our studies demonstrate female offspring of hypertensive pregnancies are not glucose intolerant by 6 months of age. Despite reduced pancreatic beta cell area in female RUPP offspring early in development, glucose handling was maintained and even improved after oral glucose challenge in older RUPP offspring. Overall, these data suggest that increased peripheral insulin sensitivity may reduce the demand for beta cell function, and our studies reinforce the idea that adverse pregnancy can have a lasting effect on development and function of the pancreas.

The impact of human umbilical cord-derived mesenchymal stem cells on the pancreatic function of type 2 diabetic mice and their regulatory role on NLRP3 inflammasomes

Objective: To investigate the effect and regulation of umbilical cord-derived mesenchymal stem cells (UC-MSCs) on islets function and NOD-like receptor family, pyrin domain containing 3 (NLRP3) and autophagy in type 2 diabetic mellitus (T2DM) mice. Methods: Experimental study. Twenty, 8-week-old, male C57BL/6J mice were selected and divided into a normal control group (n=5) and a high-fat feeding modeling group (n=15). The model of T2DM was established by high-fat feeding combined with intraperitoneal injection of low-dose streptozotocin. After successful modeling, those mice were divided into a diabetes group (n=7) and a UC-MSCs treatment group (n=7). The UC-MSCs treatment group was given UC-MSCs (1×106/0.2 ml phosphate buffer solution) by tail vein infusion once a week for a total of 4 weeks; the diabetes group was injected with the same amount of normal saline, and the normal control group was not treated. One week after the treatment, mice underwent intraperitoneal glucose tolerance tests and intraperitoneal insulin tolerance tests, and then the mice were sacrificed to obtain pancreatic tissue to detect the expressions of interleukin-1β (IL-1β) and pancreatic and duodenal homeobox 1 (PDX-1) by immunofluorescence. The bone marrow-derived macrophages were stimulated with lipopolysaccharide and adenosine triphosphate (experimental group) in vitro, then co-cultured with UC-MSCs for 24 h (treatment group). After the culture, enzyme-linked immunosorbent assay was used to detect the secretion level of IL-1β in the supernatant, and immunofluorescence staining was used to detect the expression of NLRP3 inflammasome, and related autophagy proteins. Statistical analysis was performed using unpaired one-way analysis of variance, repeated measure analysis of variance. Results: In vivo experiments showed that compared with the diabetes group, the UC-MSCs treatment group partially repaired islet structure, improved glucose tolerance and insulin sensitivity (all P<0.05), and the expression of PDX-1 increased and IL-1β decreased in islets under confocal microscopy. In vitro experiments showed that compared with the experimental group, the level of IL-1β secreted by macrophages in the treatment group was decreased [(85.9±74.6) pg/ml vs. (883.4±446.2) pg/ml, P=0.001], the expression of NLRP3 inflammasome and autophagy-related protein P62 was decreased, and the expressions of microtubule-associated protein 1 light chain 3β (LC3) and autophagy effector Beclin-1 were increased under confocal microscopy. Conclusions: UC-MSCs can reduce the level of pancreatic inflammation in T2DM mice, preserving pancreatic function. This might be associated with the ability of UC-MSCs to inhibit the activity of NLRP3 inflammasomes in macrophages and enhance autophagy levels.

New Mouse Models of Roux-en Y Gastric Bypass and One Anastomosis Gastric Bypass for Type 2 Diabetes.

Current bariatric surgery models primarily utilize mice with obesity, overlooking those with type 2 diabetes (T2DM). These models have limitations in replicating clinical procedures accurately and achieving broad applicability. This study aimed to develop novel mouse models of Roux-en-Y gastric bypass (RYGB) and one anastomosis gastric bypass (OAGB) surgeries specifically designed for T2DM research, utilizing simplified surgical techniques closely resembling clinical procedures. Eight-week-old C57/Bl6 mice, except for the Blank-Control group, were induced with T2DM by combining a high-fat diet and streptozotocin injection. RYGB involved creating a 10% gastric pouch, a 4-cm biliopancreatic limb (BL), and a 4-cm Roux limb (RL). Similarly, OAGB maintained a 10% gastric pouch and a 4-cm BL. To assess the efficacy of these models, we measured the body weight and fasting blood glucose (FBG) and conducted intraperitoneal glucose tolerance test (IPGTT), insulin tolerance test (ITT), and liver B-ultrasound, as well as a histopathological analysis of multiple organs 12weeks post-operation. The survival rates in the Blank-Control, T2DM-Sham, T2DM-RYGB, and T2DM-OAGB groups were 100% (6/6), 100% (6/6), 85.7% (6/7), and 100% (6/6), respectively. Both RYGB and OAGB surgeries similarly led to sustained weight loss, reduced the FBG levels, improved the IPGTT and ITT results, and alleviated the histopathological manifestations in multiple organs. The innovative mouse models of RYGB and OAGB surgeries effectively improve T2DM. Both surgeries demonstrate comparable efficacy in ameliorating T2DM, even when utilizing a gastric pouch of the same size and the same length of BL in OAGB.

Duration of intermittent hypoxia impacts metabolic outcomes and severity of murine NAFLD.

Obstructive sleep apnea (OSA) is associated with metabolic dysfunction, including progression of nonalcoholic fatty liver disease (NAFLD). Chronic intermittent hypoxia (IH) as a model of OSA worsens hepatic steatosis and fibrosis in rodents with diet induced obesity. However, IH also causes weight loss, thus complicating attempts to co-model OSA and NAFLD. We sought to determine the effect of various durations of IH exposure on metabolic and liver-related outcomes in a murine NAFLD model. We hypothesized that longer IH duration would worsen the NAFLD phenotype. Male C57BL/6J mice (n = 32) were fed a high trans-fat diet for 24 weeks, to induce NAFLD with severe steatohepatitis. Mice were exposed to an IH profile modeling severe OSA, for variable durations (0, 6, 12, or 18 weeks). Intraperitoneal glucose tolerance test was measured at baseline and at six-week intervals. Liver triglycerides, collagen and other markers of NAFLD were measured at sacrifice. Mice exposed to IH for 12 weeks gained less weight (p = 0.023), and had lower liver weight (p = 0.008) relative to room air controls. These effects were not observed in the other IH groups. IH of longer duration transiently worsened glucose tolerance, but this effect was not seen in the groups exposed to shorter durations of IH. IH exposure for 12 or 18 weeks exacerbated liver fibrosis, with the largest increase in hepatic collagen observed in mice exposed to IH for 12 weeks. Duration of IH significantly impacts clinically relevant outcomes in a NAFLD model, including body weight, fasting glucose, glucose tolerance, and liver fibrosis.

GIP receptor agonism improves dyslipidemia and atherosclerosis independently of body weight loss in preclinical mouse model for cardio-metabolic disease

BackgroundAgonism at the receptor for the glucose-dependent insulinotropic polypeptide (GIPR) is a key component of the novel unimolecular GIPR:GLP-1R co-agonists, which are among the most promising drugs in clinical development for the treatment of obesity and type 2 diabetes. The therapeutic effect of chronic GIPR agonism to treat dyslipidemia and thus to reduce the cardiovascular disease risk independently of body weight loss has not been explored yet.MethodsAfter 8 weeks on western diet, LDL receptor knockout (LDLR-/-) male mice were treated with daily subcutaneous injections of long-acting acylated GIP analog (acyl-GIP; 10nmol/kg body weight) for 28 days. Body weight, food intake, whole-body composition were monitored throughout the study. Fasting blood glucose and intraperitoneal glucose tolerance test (ipGTT) were determined on day 21 of the study. Circulating lipid levels, lipoprotein profiles and atherosclerotic lesion size was assessed at the end of the study. Acyl-GIP effects on fat depots were determined by histology and transcriptomics.ResultsHerein we found that treatment with acyl-GIP reduced dyslipidemia and atherogenesis in male LDLR-/- mice. Acyl-GIP administration resulted in smaller adipocytes within the inguinal fat depot and RNAseq analysis of the latter revealed that acyl-GIP may improve dyslipidemia by directly modulating lipid metabolism in this fat depot.ConclusionsThis study identified an unanticipated efficacy of chronic GIPR agonism to improve dyslipidemia and cardiovascular disease independently of body weight loss, indicating that treatment with acyl-GIP may be a novel approach to alleviate cardiometabolic disease.

Breastfeeding lifespan control of growth, maintenance, and metabolism of small intestinal epithelium.

Gastrointestinal epithelial cells respond to milk-born molecules throughout breastfeeding, influencing growth, and development. The rapid renewal of the small intestine depends on the proliferation in the crypt that drives cell fates. We used early weaning model to investigate immediate and late effects of breastfeeding on proliferation, differentiation of jejunal epithelial cells. Wistar rats were either allowed to suckle (S) until 21 postnatal days or submitted to early weaning (EW) at 15 days. By comparing ages (18, 60, and 120 days), we found that EW decreased Ki67 indices and villi height at 18 and 60 days (p < 0.05), and at 120 days they were similar between diets. Proliferative reduction and augmented expression of Cdkn1b (p27 gene) were parallel. In the stem cell niche, EW increased the number and activity (Defa24) of Paneth cells at 18 and 60 days (p < 0.05), and Lgr5 and Ascl2 genes showed inverted responses between ages. Among target cells, EW decreased goblet cell number at 18 and 60 days (p < 0.05) and increased it at 120 days (p < 0.05), whereas enteroendocrine marker genes were differentially altered. EW reduced enterocytes density at 18 days (p < 0.05), and at 120 days this population was decreased (vs. 60 days). Among cell fate crypt-controlling genes, Notch and Atoh1 were the main targets of EW. Metabolically, intraperitoneal glucose tolerance was immediately reduced (18 days), being reverted until 120 days (p < 0.05). Currently, we showed that breastfeeding has a lifespan influence on intestinal mucosa and on its stem cell compartment. We suggest that, although jejunum absorptive function is granted after early weaning, the long lasting changes in gene expression might prime the mucosa with a different sensitivity to gut disorders that still have to be further explored.

Nutritive/non-nutritive sweeteners and high fat diet contribute to dysregulation of sweet taste receptors and metabolic derangements in oral, intestinal and central nervous tissues.

Overconsumption of non-nutritive sweeteners is associated with obesity, whereas the underlying mechanisms remain controversial. This study aimed to investigate the effects of long-term consumption of nutritive or non-nutritive sweeteners with or without high fat diet on sweet taste receptor expression in nutrient-sensing tissues and energy regulation dependent on sweet-sensing. 50 Male Sprague-Dawley rats (140-160g) were assigned to 10 groups (n = 5/group). All received fructose at 2.5% or 10%, sucralose at 0.01% or 0.015% or water with a normal chow diet or high fat diet for 12weeks. Food and drink intake were monitored daily. Oral glucose tolerance test and intraperitoneal glucose tolerance test were performed at week 10 and 11 respectively. Serum was obtained for measurement of biochemical parameters. Tongue, duodenum, jejunum, ileum, colon and hypothalamus were rapidly removed to assess gene expression. Long-term consumption of sweeteners impaired glucose tolerance, increased calorie intake and body weight. A significant upregulation of sweet taste receptor expression was observed in all the four intestinal segments in groups fed 0.01% sucralose or 0.015% sucralose, most strikingly in the ileum, accompanied by elevated serum glucagon-like peptide-1 levels and up-regulated expression of sodium-dependent glucose cotransporter 1 and glucose transporter 2. A significant down-regulation in the tongue and hypothalamus was observed in groups fed 10% fructose or 0.015% sucralose, with alterations in hypothalamic appetite signals. The presence of high fat diet differentially modulates sweet taste perception in nutrient-sensing tissues. Long-term consumption of whether nutritive sweeteners or non-nutritive sweeteners combined with high fat diet contribute to dysregulation of sweet taste receptor expression in oral, intestinal and central nervous tissues.

Asprosin contributes to nonalcoholic fatty liver disease through regulating lipid accumulation and inflammatory response via AMPK signaling.

Nonalcoholic fatty liver disease (NAFLD) is a primary contributor to liver-related morbidity and mortality. Asprosin has been reported to be implicated in NAFLD. This work is to illuminate the effects of Asprosin on NAFLD and the possible downstream mechanism. The weight of NAFLD mice induced by a high-fat diet was detected. Quantitative reverse-transcription polymerase chain reaction (RT-qPCR) examined serum Asprosin expression. RT-qPCR and western blot analysis examined Asprosin expression in mice liver tissues. Intraperitoneal glucose tolerance test (IPGTT) and intraperitoneal insulin tolerance test (IPITT) were implemented. Biochemical kits tested liver enzyme levels in mice serum and liver tissues. Hematoxylin and eosin staining evaluated liver histology. Liver weight was also tested and oil red O staining estimated lipid accumulation. RT-qPCR and western blot analysis analyzed the expression of gluconeogenesis-, fatty acid biosynthesis-, fatty acid oxidation-, and inflammation-associated factors. Besides, western blot analysis examined the expression of AMP-activated protein kinase (AMPK)/p38 signaling-associated factors. In palmitic acid (PA)-treated mice hepatocytes, RT-qPCR and western blot analysis examined Asprosin expression. Lipid accumulation, gluconeogenesis, fatty acid biosynthesis, fatty acid oxidation, and inflammation were appraised again. Asprosin was overexpressed in the serum and liver tissues of NAFLD mice and PA-treated mice hepatocytes. Asprosin interference reduced mice body and liver weight, improved glucose tolerance and diminished liver injury in vivo. Asprosin knockdown alleviated lipid accumulation and inflammatory infiltration both in vitro and in vivo. Additionally, Asprosin absence activated AMPK/p38 signaling and AMPK inhibitor Compound C reversed the impacts of Asprosin on lipid accumulation and inflammatory response. Collectively, Asprosin inhibition suppressed lipid accumulation and inflammation to obstruct NAFLD through AMPK/p38 signaling.

Sphingosine Kinase 2 Knockout Mice Resist HFD-Induced Obesity Through Increasing Energy Expenditure.

It has been reported that sphingosine kinase (SK) 2 plays a role in maintaining metabolism and glucose homeostasis. However, the mechanism remains uncertain. The present research aimed to further investigate the effect of SK2 knockout on high-fat diet (HFD)-induced obesity and metabolic regulation. Male SK2-/- and wild-type (WT) control mice were challenged with HFD for 8 weeks. Then, body composition, inguinal white adipose tissue (IWAT) histology, intraperitoneal glucose tolerance tests (IPGTT), and metabolic parameters were examined, and expression levels of uncoupling protein 1 (UCP1), a key molecular marker of thermogenesis, in IWAT were determined. After 8 weeks of HFD challenge, compared with WT mice, SK2-/- mice displayed decreased whole body, epididymal white adipose tissue (EWAT) and IWAT weights, reduced fat/lean body mass ratios and inguinal adipocytes size; also, SK2-/- mice exhibited improved intraperitoneal glucose tolerance. Next, elevated energy expenditure was observed in SK2-/- mice compared with WT mice; however, neither food intake nor physical activity showed obvious difference between SK2-/- and WT mice. Furthermore, we found that the expressions of UCP1 was markedly increased in IWAT from SK2-/- mice. SK2-/- mice may resist HFD-induced obesity through increasing energy expenditure by promoting thermogenesis in the beige adipose tissue.

Formononetin suppresses hyperglycaemia through activation of GLUT4-AMPK pathway

Background: Formononetin (FMN) is a flavonoid that has different pharmacological effects. Thus, the anti-diabetic effects of FMN has been investigated in a high-fat diet/Streptozotocin-(HFD/STZ)-induced diabetes mice model. Methods: Mice were fed with HFD followed by STZ. Diabetic mice were treated orally with FMN or metformin for 28 days before collecting plasma and soleus muscle for further analysis. Results: FMN reduced serum glucose (p&amp;gt;0.001) and increased serum insulin in diabetic group compared to the vehicle control. Additionally, FMN decreased homeostasis model assessment of insulin resistance (HOMA-IR). Fasting glucose level was also reduced with FMN during the intraperitoneal glucose tolerance test (IPGTT). GLUT4 and p-AMPK-α1 were upregulated following treatment with FMN. LDL, triglyceride, and cholesterol were reduced in diabetic mice treated with FMN. FMN reduced MDA, increased GSH levels , and reduced GSSG levels in diabetic mice. Conclusion: FMN could represent a promising therapeutic agent to treat T2D.

Schisandrin B, a potential GLP-1R agonist, exerts anti-diabetic effects by stimulating insulin secretion

Diabetes mellitus is a metabolic disease that is characterized by elevated blood sugar. Although glucagon-like peptide-1 receptor agonists (GLP-1RA) lower blood glucose in a glucose-dependent manner, most of them are macromolecule polypeptides. Macromolecular peptides are relatively expensive and inconvenient compared with small molecules. Therefore, this study sought to identify the small molecules binding to GLP-1R via cell membrane chromatography (CMC), confirm their agonistic activity, and further study its beneficial effects in a mouse model of type 2 diabetes mellitus (T2DM) induced by a combination of high-fat diet and streptozotocin. We used CMC, calcium imaging and molecular docking techniques to screen and identify the potential small molecule Schisandrin B (Sch B), which exhibits a strong binding effect to GLP-1R, from the small molecule library of traditional Chinese medicine. Through in-vitro experiments, we found that Sch B stimulated insulin secretion in β-TC-6 cells, while GLP-1R antagonist Exendin9-39, adenylate cyclase inhibitor SQ22536, and protein kinase A (PKA) inhibitor H89 could significantly inhibit the insulin secretion induced by Sch B. In vivo, Sch B significantly improved fasting blood glucose levels, intraperitoneal glucose tolerance test damage, and the status of pancreatic tissue damage, and reduced serum insulin levels, total cholesterol, triglyceride and low density lipoprotein in T2DM mice. These results indicate that Sch B alleviates T2DM by promoting insulin release through the GLP-1R/cAMP/PKA signaling pathway, suggesting that Sch B may be a potential GLP-1RA, which is expected to provide a new therapeutic strategy for the prevention and treatment of T2DM.

A gelatin hydrogel nonwoven fabric improves outcomes of subcutaneous islet transplantation

Subcutaneous islet transplantation is a promising treatment for severe diabetes; however, poor engraftment hinders its prevalence. We previously reported that a recombinant peptide (RCP) enhances subcutaneous islet engraftment. However, it is impractical for clinical use because RCP must be removed when transplanting islets. We herein investigated whether a novel bioabsorbable gelatin hydrogel nonwoven fabric (GHNF) could improve subcutaneous islet engraftment. A silicon spacer with or without GHNF was implanted into the subcutaneous space of diabetic mice. Syngeneic islets were transplanted into the pretreated space or intraportally (Ipo group). Blood glucose, intraperitoneal glucose tolerance, immunohistochemistry, CT angiography and gene expression were evaluated. The cure rate and glucose tolerance of the GHNF group were significantly better than in the control and Ipo groups (p < 0.01, p < 0.05, respectively). In the GHNF group, a limited increase of vWF-positive vessels was detected in the islet capsule, whereas laminin (p < 0.05), collagen III and IV were considerably enhanced. TaqMan arrays revealed a significant upregulation of 19 target genes (including insulin-like growth factor-2) in the pretreated space. GHNF markedly improved the subcutaneous islet transplantation outcomes, likely due to ECM compensation and protection of islet function by various growth factors, rather than enhanced neovascularization.