Model Of Type 2 Diabetes Research Articles

181-OR: Pancreatic Gene Therapy Durably Improves Glycemia and Delays Disease Progression in a Murine Model of Type 2 Diabetes

Beta-cell (β-cell) failure is a root cause of the progression of type 2 diabetes (T2D). GLP-1 receptor agonists (GLP1RA) have proven clinical efficacy and improve β-cell function. However, systemic side effects limit patient adherence and long-term efficacy. Localized pancreatic GLP1RA production may engender durable islet cell benefit while diminishing side effects. We developed a novel adeno-associated virus (AAV) gene therapy delivery platform to enable local and durable production of therapeutic proteins by the pancreas. We assessed to what degree a β-cell restricted GLP1RA gene therapy impacts disease progression in the db/db mouse compared to semaglutide (Sema). To establish a baseline for chronically administered systemic GLP1RA, Sema (10 nmol/kg) or vehicle were given daily to 5-week-old mice for 10 weeks (n=8/group). Sema treated mice had a 64% decrease in fasting blood glucose (FBG; p<0.0001) and a 3.5-fold increase in fasting insulin (FI; p=0.01) across the time course. Glucose tolerance was significantly improved during IPGTT at weeks 3, 6, and 9 (p<0.001). To determine the impact of a single dose GLP1RA gene therapy, 1) β-cell restricted AAV-GLP1RA, 2) AAV control, or 3) vehicle were given to 5-week-old mice (n=8/group). Remarkably, AAV-GLP1RA treatment decreased FBG levels by 70% (p<0.0001) and elevated FI by 1.9-fold (p<0.01) compared to controls for 10 weeks. Glucose tolerance was improved during IPGTT at weeks 3, 5, 7, and 9 (p<0.01). AAV-GLP1RA protein was undetectable in serum and restricted to the islet, suggesting improved glycemic control was due to intra-islet GLP1RA production and signaling. These results demonstrate that a single dose β-cell restricted GLP1RA gene therapy can comparably improve glycemia and delay disease progression in a murine model of T2D when compared to chronic systemic GLP1RA administration. These data provide proof of concept that a gene therapy has the potential to durably treat metabolic diseases, including T2D. Disclosure A.L.Fitzpatrick: Employee; Fractyl Health, Inc. E.Cozzi: Employee; Fractyl Health, Inc. J.Wainer: Employee; Fractyl Health, Inc. R.Reese: Employee; Fractyl Health, Inc. N.Khanna: Employee; Fractyl Health, Inc. J.Caplan: Employee; Fractyl Health, Inc. H.Rajagopalan: Employee; Fractyl Health, Inc. J.A.West: Employee; Fractyl Health, Inc. Funding Fractyl Health, Inc.

802-P: Beneficial Effects of a Functionally Selective Insulin on Vascular Function and Liver Triglycerides

Selective insulin resistance, where insulin's ability to lower blood glucose via the Akt signaling pathway gradually decreases while retaining its effectiveness in activating other signaling pathways (e.g. MAPK), is a key pathophysiological mechanism underlying the hyperglycemia, dyslipidemia and vascular dysfunction in type 2 diabetes (T2D). Here we hypothesize that a selective signaling insulin analog that activates Akt signaling but has a considerably reduced effect on MAPK should counteract selective insulin resistance and provide effective glucose lowering with improved vascular function, reduced hepatic lipid accumulation and generally alleviate insulin resistance over time compared to human insulin (HI). NNC-965, a basal insulin analog with 4 amino acid modifications and a C18 fatty diacid, was designed as a functionally selective insulin, with greater Akt than MAPK activation in several cellular systems and in vivo. NNC-965 fully activates glucose regulating pathways, including inhibition of glucose output, glycogen accumulation and inhibition of gluconeogenic mRNAs in rat hepatocytes as well as stimulation of glucose uptake and inhibition of lipolysis in rat adipocytes. In contrast, NNC-965 displayed reduced induction of lipogenic mRNA and de novo lipogenesis in rat liver cells compared to HI. In a mouse model of T2D, treatment with NNC-965 for 6 weeks to the same glucose level as insulin 700 (an insulin degludec-like analog) resulted in 35% less liver triglycerides and improved acetylcholine mediated vasodilation in ex vivo studies using mesenteric arterioles. In conclusion, NNC-965 is a novel functionally selective insulin analog that can potentially improve insulin resistance and eventually reduce cardiovascular risk by restoring balanced insulin signaling. Disclosure G.S.Olsen: Employee; Novo Nordisk A/S. G.Povlen: Employee; Novo Nordisk. T.A.Pedersen: Employee; Novo Nordisk A/S. R.Slaaby: Employee; Novo Nordisk, Stock/Shareholder; Novo Nordisk. B.F.Hansen: Employee; Novo Nordisk A/S, Stock/Shareholder; Novo Nordisk A/S. T.Glendorf: Employee; Novo Nordisk A/S, Stock/Shareholder; Novo Nordisk A/S. D.Demozay: None. H.Hvid: Employee; Novo Nordisk A/S. E.Nishimura: Employee; Novo Nordisk A/S. J.Brandt: Employee; Novo Nordisk A/S.

1621-P: Commercially Available Stevia-Based Sweetener, Antidiabetic or Toxic—An Ad Libitum Feeding Study in a Type 2 Diabetes Model of Rat

The use of non-nutritive sweeteners as sugar substitutes by overweight, obese and diabetic individuals has been increased rapidly in recent years, when Stevia is the most popular one not only due to its natural source of origin but also for it antidiabetic potential. However, the effects commercially available stevia-based NNS are not investigated at all. The present study was conducted to investigate the effects of ad libitum consumption of commercially available stevia-based non-nutritive sweetener (NNS) in an experimentally-induced rat model of type 2 diabetes (T2D). Seven-week-old male Sprague-Dawley rats were randomly divided into three groups, namely: Normal Control (NC), Diabetic Control (DBC) and Diabetic Stevia (DSTV). T2D was induced in the DBC and DSTV groups only. The control groups were received normal drinking water, whilst rats in the DSTV group were administered with stevia-containing NNS solution, at a concentration equivalent to the sweetness of 10% sucrose. After 13 week intervention, although food and fluid intake, body weight, weekly blood glucose, glucose tolerance, serum insulin, fructosamine, ALT, ALP, creatinine and brain, liver and pancreatic histopathology were not significantly affected; serum AST, LDH and CK-MB as well as heart and kidney histopathology were significantly deteriorated in stevia-based NNS consuming group compared to the DBC group. The data of this study suggest that uncontrolled consumption of stevia-based NNS has no significant antidiabetic effect but have some toxicological effects in an animal model of T2D. Hence, diabetic patients consuming stevia-based NNS should limit their daily intake. Disclosure S. Islam: None. S.N. Dlamini: None. Funding South African Sugar Association (Project 233)

1-LB: Evaluating the Effectiveness of the Novel Somatostatin Receptor Antagonist (SSTR2a) ZT-01 for Hypoglycemia Prevention in a Rodent Model of Type 2 Diabetes

Background: Few pharmacological strategies exist to prevent hypoglycemia in diabetes, other than reducing the intensity of glucose-lowering therapy. SSTR2a treatment increases glucagon counterregulation and reduces the time spent in hypoglycemia in rodent models of type 1 diabetes (T1D), but the utility of this approach in type 2 diabetes (T2D) is unclear. The purpose of this study was to test the effect of acute SSTR2a treatment in a rodent model of hypoglycemia in T2D. Methods: High fat fed (HFF), low dose streptozotocin (35 mg/kg) T2D rats received SSTR2a treatment (subcutaneous ZT-01 3 mg/kg) or vehicle (N=9-11/group) 60 min before the induction of hypoglycemia using rapid-acting insulin (12 U/kg). Glycemia, glucagon and c-peptide levels were measured intermittently pre- and post-dosing. Results: T2D in the rats was characterized by significantly higher baseline glucose (21.8 ± 4.7 vs 6.5 ± 0.7 mmol/L, p<0.05) and HbA1c (8.6 ± 0.6% vs 5.5 ± 0.5%; p<0.0001) levels relative to HFF controls (n=3). T2D rats also displayed reduced c-peptide levels relative to controls (3.1 ± 1.3 vs 6.1 ± 1.2 ng/ml, p<0.05). During hypoglycemic challenge (T2D rats only), SSTR2a elevated glucagon levels relative to vehicle treatment (glucagon Cmax: 156 ± 50 vs 77 ± 46 pg/ml, p<0.01) and reduced the incidence of hypoglycemia by ~40% (5/8 SSTR2a treated vs 9/9 vehicle treated rats). In those that developed hypoglycemia, the average time to hypoglycemia onset was delayed (103.1± 24.6 vs 66.1 ± 23.6 min, p<0.05) with SSTR2a compared to vehicle. Conclusion: SSTR2a treatment increases glucagon levels in this rodent model of T2D, which appears to reduce the risk for hypoglycemia following bolus insulin dosing. Disclosure N. C. D'souza: None. M. Nejad-mansouri: None. R. Liggins: Employee; Zucara Therapeutics, Stock/Shareholder; Zucara Therapeutics. O. Chan: None. M. C. Riddell: Advisory Panel; Zealand Pharma A/S, Zucara Therapeutics, Indigo Diabetes, Consultant; Lilly Diabetes, Eli Lilly and Company, Jaeb Center for Health Research, Speaker's Bureau; Dexcom, Inc., Novo Nordisk, Sanofi, Stock/Shareholder; Supersapiens, Zucara Therapeutics. P. Zaree bavani: None. J. Aiken: None. E. G. Hoffman: None. S. C. Atherley: None. S. Champsi: None. N. Aleali: None. D. Shakeri: None. M. El-zahed: None. N. Akbarian: None. Funding GlycoNet (CD-85)

1624-P: Hudev-PRE, a Combination of Plant Extracts, Improves Glucose Homeostasis in Both High-Fat Diet C57Bl/6J and Ob/Ob Mice

Despite advances in the understanding of the pathogenesis of type 2 diabetes (T2D), new therapeutic & nutritional solutions are needed to delay its emergence and prevent the development of its associated complications. Here, we tested the effect of HUDEV-PRE, an original mixture of plant extracts, on glucose homeostasis in in two different mouse models of T2D. In a first experiment, 8 weeks old C57Bl/6J males were fed with high-fat diet during 8 weeks to induce insulin resistance. In a second set-up, we used 6 weeks old Ob/Ob males. In both experiments, mice received a double daily oral administration of vehicle, metformin (150mg/kg) or HUDEV-PRE for 30 days. Food intake, body weight change, random fed plasma glucose, cholesterol and triglyceride levels were measured once weekly. Finally, oral glucose tolerance tests (GTT) were performed after 7 and 21 days of treatment. In both models, HUDEV-PRE did not alter food intake and body weight. Interestingly, a rapid, sustainable and significant reduction of random fed blood glucose levels was observed in HFD fed C57Bl/6J and Ob/Ob mice receiving metformin or HUDEV-PRE administration. In HFD fed C57Bl/6J mice, GTT revealed no significant effects at day 7 but a strong improvement of glucose tolerance in mice treated for 21 days with metformin or HUDEV-PRE compared to control vehicle treated mice. In Ob/Ob mice, we observed similar results and the glucose tolerance was even improved after only 7 days of treatment. Finally, at day 21, we also measured a significant reduction of fasting plasma insulin levels and HOMA-IR in both mouse models treated with HUDEV-PRE. Together, our data demonstrate that HUDEV-PRE rapidly improve glucose homeostasis in two mouse models of T2D. Although additional studies are warranted to decipher the mechanisms of action, these findings indicate that HUDEV-PRE could represent a nutritional supplement of interest to delay the onset of insulin resistance and T2D in patients at metabolic risk. Disclosure C.Le may: None. J.Blua: None. B.Cariou: Board Member; Eli Lilly and Company, Novartis, Research Support; Sanofi, Speaker's Bureau; Abbott, AstraZeneca, Novo Nordisk, Sanofi.

990-P: Estimating the National Costs of T2DM in the UK within the Context of Contemporary Guidelines

Background: The updated National Institute for Health and Care Excellence (NICE) type 2 diabetes (T2D) guidelines extend the recommendation of SGLT2 inhibitors (SGLT2i) for hyperglycaemia management to include their use in those with atherosclerotic cardiovascular disease (ASCVD), chronic heart failure (HF), chronic kidney disease (CKD) or high CVD risk. Our study estimates the potential cost consequence in the UK of the broad positioning of SGLT2i within updated guidelines (NG28-2022) versus previous guidelines (NG28-2015). Methods: The Cardiff T2D model was used to project lifetime outcomes and costs for T2D patients across established UK treatment pathways including metformin, sulfonylurea, DPP-4 inhibitors and NPH insulin with or without SGLT2i combination to reflect former vs. updated guidelines. Analyses were conducted in four subgroups (ASCVD, HF with reduced ejection fraction (HFrEF), CKD, high CVD risk). Projected outcomes were extrapolated to national level using population estimates from NICE’s guideline companion resource impact report. Results: Predicted lifetime costs for 1.7 Mn SGLT2i eligible T2D patients in the UK were estimated at £87.1 Bn with NG28-2022 compared to £101.7 Bn with NG28-2015. Net savings associated with NG28-2022 management of £14.56 Bn were attributable to comorbid CKD (£5.09 Bn), high CVD risk (£4.77 Bn), ASCVD (£3.96 Bn) and comorbid HFrEF (£0.74 Bn). Overall net savings were predicted despite an increase in pharmacy costs of £5.57 Bn. Changes in metabolic parameters and reduction in cardiovascular and kidney progression rates were predicted to prevent 20183 myocardial infarction events, 66651 HF events and 140303 events of end stage kidney failure. The magnitude of savings was a combination of event reductions and the number of eligible patients in subgroups. Conclusion: Our study indicates that uptake of SGLT2 inhibitors in line with NICE guidelines has the potential to improve health and be cost saving despite an increase in pharmacy costs. Disclosure P.Mcewan: Other Relationship; AstraZeneca. V.Foos: Other Relationship; AstraZeneca. R.Martin: Employee; AstraZeneca. J.Chen: Employee; AstraZeneca, Eli Lilly and Company.

Metabolomics reveals the role of Lactobacillus plantarum SHY130 in hepatic metabolic regulation in a mouse model of type 2 diabetes.

Among type 2 diabetes (T2D) patients, the incidence rate of liver metabolic disorders is much higher than that in healthy subjects. It was observed in our previous research that diabetic symptoms were improved by Lactobacillus plantarum SHY130 (LPSHY130) isolated from yak yogurt in a murine model of type 2 diabetes (T2D). This study sought to investigate the LPSHY130-mediated hepatic metabolic regulation in a murine model of T2D. Treatment with LPSHY130 improved liver function and pathological damage in diabetic mice. Untargeted metabolome analysis revealed the T2D-induced changes in 11 metabolites were regulated after LPSHY130 treatment, mainly involving purine metabolism, amino acid metabolism, choline metabolism, and pantothenate and CoA biosynthesis pathways. In addition, correlation analysis indicated that hepatic metabolic changes can be adjusted by the intestinal microbiota. Overall, this study suggests that treatment with LPSHY130 relieves liver injury and regulates liver metabolism in a murine model of T2D, thus providing a theoretical basis for the use of probiotics as dietary supplements to regulate hepatic metabolic disorders associated with T2D. This article is protected by copyright. All rights reserved.

GHRH agonist MR-409 protects β-cells from streptozotocin-induced diabetes

Patients with type 1 diabetes (T1D) suffer from insufficient functional β-cell mass, which results from infiltration of inflammatory cells and cytokine-mediated β-cell death. Previous studies demonstrated the beneficial effects of agonists of growth hormone-releasing hormone receptor (GHRH-R), such as MR-409 on preconditioning of islets in a transplantation model. However, the therapeutic potential and protective mechanisms of GHRH-R agonists on models of T1D diabetes have not been explored. Using in vitro and invivo models of T1D, we assessed the protective propertie of the GHRH agonist, MR409 on β-cells. The treatment of insulinoma cell lines and rodent and human islets with MR-409 induces Akt signaling by induction of insulin receptor substrate 2 (IRS2), a master regulator of survival and growth in β-cells, in a PKA-dependent manner. The increase in cAMP/PKA/CREB/IRS2 axis by MR409 was associated with decrease in β-cell death and improved insulin secretory function in mouse and human islets exposed to proinflammatory cytokines. The assessment of the effects of GHRH agonist MR-409 in a model of T1D induced by low-dose streptozotocin showed that mice treated with MR-409 exhibited better glucose homeostasis, higher insulin levels, and preservation of β-cell mass. Increased IRS2 expression in β-cells in the group treated with MR-409 corroborated the invitro data and provided evidence for the underlying mechanism responsible for beneficial effects of MR-409 invivo. Collectively, our data show that MR-409 is a novel therapeutic agent for the prevention and treatment of β-cells death in T1D.

Longitudinal Characterization of the Gut Microbiota in the Diabetic ZDSD Rat Model and Therapeutic Potential of Oligofructose.

The complex development of type 2 diabetes (T2D) creates challenges for studying the progression and treatment of the disease in animal models. A newly developed rat model of diabetes, the Zucker Diabetic Sprague Dawley (ZDSD) rat, closely parallels the progression of T2D in humans. Here, we examine the progression of T2D and associated changes in the gut microbiota in male ZDSD rats and test whether the model can be used to examine the efficacy of potential therapeutics such as prebiotics, specifically oligofructose, that target the gut microbiota. Bodyweight, adiposity, and fed/fasting blood glucose and insulin were recorded over the course of the study. Glucose and insulin tolerance tests were performed, and feces collected at 8, 16, and 24 weeks of age for short-chain fatty acids and microbiota analysis using 16s rRNA gene sequencing. At the end of 24 weeks of age, half of the rats were supplemented with 10% oligofructose and tests were repeated. We observed a transition from healthy/nondiabetic to prediabetic and overtly diabetic states, via worsened insulin and glucose tolerance and significant increases in fed/fasted glucose, followed by a significant decrease in circulating insulin. Acetate and propionate levels were significantly increased in the overt diabetic state compared to healthy and prediabetic. Microbiota analysis demonstrated alterations in the gut microbiota with shifts in alpha and beta diversity as well as alterations in specific bacterial genera in healthy compared to prediabetic and diabetic states. Oligofructose treatment improved glucose tolerance and shifted the cecal microbiota of the ZDSD rats during late-stage diabetes. These findings underscore the translational potential of ZDSD rats as a model of T2D and highlight potential gut bacteria that could impact the development of the disease or serve as a biomarker for T2D. Additionally, oligofructose treatment was able to moderately improve glucose homeostasis.

Longitudinal characterization of the gut microbiota in the ZDSD rat model of diabetes

The complex development of type 2 diabetes (T2D) creates challenges for studying its progression in animal models, which often lack transition through the prediabetic state or fail to fully develop the multifaceted aspects of T2D. However, studying T2D development and progression in humans is costly with extensive limitations. A newly developed rat model of T2D, the Zucker Diabetic Sprague Dawley (ZDSD) rat, more closely parallels the progression of T2D in humans. Our goal was to examine T2D progression and the associated changes in the gut microbiota in the ZDSD model and test whether the model can be used to examine potential therapeutics targeting the gut microbiota. As physiological parameters like blood glucose and insulin levels can impact the gut microbiota and vice versa, we anticipate significant shifts in the gut microbiota as the ZDSD rats progress from a healthy to prediabetic to overt diabetic phenotype. Bodyweight, adiposity, and fed/fasting blood glucose and insulin were recorded throughout the progression of T2D in male ZDSD rats over 24 weeks. Glucose and insulin tolerance tests were performed, and feces collected for microbiota analysis using 16s rRNA gene sequencing at 8, 16, and 24 weeks. At the end of 24 weeks, half of the rats were supplemented with oligofructose (OFS) in their drinking water and tests repeated. Over the 24 weeks, we observed a transition from nondiabetic to prediabetic and overtly diabetic states, via worsened insulin and glucose tolerance and significant increases in fed/ fasted glucose values, followed by a significant decrease in circulating insulin. Microbiota analysis demonstrated alterations in the gut microbiota throughout the development of diabetes with shifts in alpha and beta diversity as well as alterations in specific bacterial genera in healthy compared to prediabetic and diabetic states. OFS treatment significantly increased body weight and adiposity, improved glucose tolerance, and shifted the cecal microbiota of the ZDSD rats during late-stage diabetes. These findings demonstrate the translational potential of ZDSD rats as a T2D model and highlight the potential for the gut microbiota to both impact the development of the disease, as well as serve as a biomarker for T2D. Additionally, OFS treatment was able to moderately improve glucose homeostasis in the ZDSD model. Arizona Biomedical Research Commission New Investigator Award (ADHS18-198857), National Institute of Food and Agriculture (67017-29252), and NIDDK (R01ES033993). 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.

Beta cell expression of ST8Sia6 protects from autoimmune diabetes in the murine NOD model

Abstract In this study, we leveraged immunomodulatory Siglec-sialic acid interactions to protect beta-cells against autoimmune rejection in Type 1 Diabetes (T1D). Our lab previously demonstrated that the sialyltransferase ST8Sia6 generates ligands that bind the Siglec-E receptor expressed on murine islet-resident macrophages. Here, mice were engineered to express ST8Sia6 in beta cells (βST mice), backcrossed to the non-obese diabetic (NOD) mouse model of T1D, and followed for disease. 60% of female littermates spontaneously developed disease by 300 days, compared to only 6% in female βST mice. Histologic analysis of pancreas sections from non-diabetic βST and littermate mice suggested a similar degree of immune infiltration in early life, but drastically reduced insulitis only in βST mice at later timepoints. This was not due to an absence of autoreactive T cells, as an anti-PD-L1 challenge resulted in similarly rapid induction of disease in both βST and littermate mice. Our genetic model allows for temporal control of ST8Sia6 expression in βST mice using the tet-off system. Treating our mice with doxycycline at 20 weeks of age resulted in persistent protection compared to age matched littermates, while the same treatment at 8 weeks of age led to similar incidence of diabetes between βST mice and littermate controls. Flow cytometric analysis of islet infiltrating immune cells from euglycemic mice at 14 weeks of age demonstrated reductions in short-lived effector CD8 T cells and increased thymically derived Tregs in βST mice compared to littermate controls. These results highlight the therapeutic potential of sialyltransferase mediated immune regulation and present a potential path toward improved curative approaches for T1D. Supported by grants from NIH (5R21AI135858-02, 1F30DK127564)

Comprehensive Study of Untargeted Metabolomics and 16S rRNA Reveals the Mechanism of Fecal Microbiota Transplantation in Improving a Mouse Model of T2D.

Fecal microbiota transplantation (FMT) has emerged as a new therapy targeting gastrointestinal microbiota for the treatment of a growing number of diseases in recent years. Previous studies have suggested that FMT may be a potential therapy for type 2 diabetes (T2D), but the underlying mechanism remains unclear. Therefore, in the present study, we aimed to investigate the role of FMT in T2D and its underlying mechanisms. To induce T2D, mice were fed a high-fat diet and injected with low-dose streptozotocin (STZ) for four weeks. The mice were then randomly divided into four groups: control group (n = 7), T2D group (n = 7), metformin (MET)-treated group (n = 7), and FMT group (n = 7). The MET group was orally administered 0.2 g/kg MET, the FMT group was orally administered 0.3 mL of bacterial solution, and the other two groups were orally administered the same volume of saline for four weeks. Serum and fecal samples were collected for non-targeted metabolomics, biochemical indicators, and 16S rRNA sequencing, respectively. Our results demonstrated that FMT had a curative effect on T2D by ameliorating hyperlipidemia and hyperglycemia. Using 16S rRNA sequencing and serum untargeted metabolomic analysis, we found that FMT could restore the disorders of gastrointestinal microbiota in T2D mice. Moreover, corticosterone, progesterone, L-urobilin, and other molecules were identified as biomarkers after FMT treatment. Our bioinformatics analysis suggested that steroid hormone biosynthesis, arginine, proline metabolism, and unsaturated fatty acid biosynthesis could be potential regulatory mechanisms of FMT. In summary, our study provides comprehensive evidence for the role of FMT in the treatment of T2D. FMT has the potential to become a promising strategy for the treatment of metabolic disorders, T2D, and diabetes-related complications.

Treatment with the ADAM17 sheddase inhibitor, phosphatidylserine, improves endothelial function and reduces arterial stiffness in diabetic mice

Patients with type 2 diabetes (T2D) have an increased incidence of cardiovascular disease (CVD) morbidity and mortality. Indeed, CVD is the primary cause of death in T2D. Arterial stiffness and hypertension are both implicated in the progression of CVD in T2D. Moreover, arterial stiffening is posited to precede the development of hypertension and is associated with a higher risk for incidence of T2D. We propose that a central mediator of these pathologies is the aberrant upregulation of protein sheddase(s) that damage mechanosenstive structures in the endothelium leading to endothelial dysfunction and subsequent increased arterial stiffness. We have previously demonstrated that the sheddase/metallopeptidase, a disintegrin and matrix metalloproteinase (ADAM17), is upregulated in the vascular endothelium of patients with T2D, while others have shown that exogenous phosphatidylserine (PS) can work as a competitive inhibitor of ADAM17 sheddase activity. Therefore, we hypothesized that inhibition of ADAM17 with PS would ameliorate endothelial dysfunction in a mouse model of T2D (db/db) by improving endothelial mechanosensation, and that this effect would be associated with reductions in blood pressure and arterial stiffness. We tested this hypothesis in 20 db/db male mice aged 9 weeks that were randomized to receive a daily peanut butter pellet as vehicle control or the pellet with PS (200 mg/kg/day) for 28 days. A third group of 10 wild-type C57/Bl6 male mice served as untreated controls. All reported differences are significant at P<0.05. Compared with wild-types, db/db control mice had elevated systolic blood pressure and pulse wave velocity, whereas PS treatment reduced both when compared with db/db controls. Excised mesenteric arteries were assessed for vasodilatory responses using pressure myography and db/db control mice showed impaired flow-mediated dilation (FMD) compared to wild-types. FMD was restored in PS-treated db/db mice. Aortas, femoral and mesenteric arteries were assessed for mechanical and structural characteristics. All of these arteries displayed increased incremental modulus of elasticity (increased stiffness) in db/db control mice compared with wilt-types. PS treatment reduced arterial stiffness across arteries in db/db mice. Our findings indicate that PS treatment improves endothelial function and reduces arterial stiffness in diabetic mice and suggest that PS may be a beneficial therapeutic approach to improve overall vascular function in the setting of T2D. R01HL151384 (to LAML and JP) and R01HL153264 (to LAML and JP) 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.

Alterations of the intestinal mucus layer correlate with dysbiosis and immune dysregulation in human Type 1 Diabetes

In preclinical models of Type 1 Diabetes (T1D) the integrity of the gut barrier (GB) is instrumental to avoid dysregulated crosstalk between the commensal microbiota and immune cells and to prevent autoimmunity. The GB is composed of the intestinal epithelial barrier (IEB) and of the mucus layer containing mucins and antimicrobial peptides (AMPs) that are crucial to maintain immune tolerance. In preclinical models of T1D the alterations of the GB primarily affect the mucus layer. In human T1D increased gut permeability and IEB damage have been demonstrated but the integrity of the mucus layer was never assessed. We evaluated GB integrity by measuring serological markers of IEB damage (serological levels of zonulin) and bacterial translocation such as lipopolysaccharide binding protein (LBP) and myeloid differentiation protein 2 (MD2), and mRNA expression of tight junction proteins, mucins and AMPs in intestinal tissue of T1D patients and healthy controls (HC). Simultaneously, we performed immunological profiling on intestinal tissue and 16S rRNA analysis on the mucus-associated gut microbiota (MAGM). Our data show a GB damage with mucus layer alterations and reduced mRNA expression of several mucins (MUC2, MUC12, MUC13, MUC15, MUC20, MUC21) and AMPs (HD4 and HD5) in T1D patients. Mucus layer alterations correlated with reduced relative abundance of short chain fatty acids (SCFA)-producing bacteria such as Bifidobacterium dentium, Clostridium butyricum and Roseburia intestinalis that regulate mucin expression and intestinal immune homeostasis. In T1D patients we also found intestinal immune dysregulation with higher percentages of effector T cells such as T helper (Th) 1, Th17 and TNF-α+ T cells. Our data show that mucus layer alterations are present in T1D subjects and associated with dysbiosis and immune dysregulation. Research Grants from the Juvenile Diabetes Foundation (Grant 1-INO-2018-640-A-N to MF and 2-SRA-2019-680-S-B to JD) and from the Italian Ministry of Health (Grant RF19-12370721 to MF).

Corchorus olitorius extract exhibit anti-hyperglycemic and anti-inflammatory properties in rodent models of obesity and diabetes mellitus.

Obesity and type 2 diabetes (T2D) are chronic conditions with detrimental impacts on the overall health of individuals. Presently, the use of pharmacological agents in obesity and T2D offers limited benefits and pose side effects. This warrant studies on remedies that are less toxic and inexpensive while effective in ameliorating secondary complications in obesity and T2D. Plant-based remedies have been explored increasingly due to their remarkable properties and safety profile. We searched for pre-clinical evidence published from inception until 2023 on PubMed, Scopus, Google, and Semantic scholar on Corchorus olitorius (C. olitorius) in both obesity and T2D. Our focus was to understand the beneficial impact of this plant-based remedy on basic glycemic, lipid, inflammatory, and biomarkers of oxidative stress. The evidence gathered in this review suggests that C. olitorius treatment may significantly reduce blood glucose, body weight, total cholesterol, triglycerides, and low-density lipoprotein (LDL) in concomitant with increasing high-density lipoprotein-cholesterol (HDL-c) in rodent models of obesity and T2D. Interestingly, this effect was consistent with the reduction of malonaldehyde, superoxide dismutase and catalases, tumor necrosis factor-alpha, interleukins, and leptin. Some of the mechanisms by which C. olitorius reduces blood glucose levels is through stimulation of insulin secretion, increasing β-cell proliferation, thus promoting insulin sensitivity; the process which is mediated by ascorbic acid present in this plant. C. olitorius anti-hyperlipidemia is attributable to the content of ferulic acid found in this plant, which inhibits 3-Hydroxy-3-methyl glutaryl coenzyme A (HMG-CoA) reductase inhibitors and thus results in reduced synthesis of cholesterol and increased hepatic LDL-c receptor expression, respectively. The present review provides extensive knowledge and further highlights the potential benefits of C. olitorius on basic metabolic parameters, lipid profile, inflammation, and oxidative stress in rodent models of obesity and T2D.

Red honeybush (Cyclopia genistoides) tea mitigates oxidative imbalance and hyperlipidemia, while improving glucose homeostasis in type 2 diabetic rats

Red honeybush tea (RHT) is a tea product developed from Cyclopia spp. which is endemic to South Africa. Aside refreshment, RHT has over the years been used traditionally in the treatment of various diseases including type 2 diabetes. This study investigated the in vivo antioxidant and anti-diabetic activity of RHT concentrated hot water extract in type 2 diabetes (T2D) model of rats. T2D was induced starting with feeding 10 % fructose solution ad libitum for 2 weeks followed by a single intraperitoneal injection of streptozotocin (40 mg/kg body weight (BW)). Five weeks of treatment of RHT led to significant (P < 0.05) elevation in serum insulin, pancreatic β-cell function, HDL-c levels with concomitant decrease in AST, ALT, ALP, urea, CK-MB, fructosamine, total cholesterol, triglycerides, LDL-c, and insulin resistance in diabetic rats. RHT also significantly (P < 0.05) decreased MDA levels and enhanced level of GSH, activity of SOD, catalase, GR in most of organs (pancreas, liver, kidneys, and heart). Significantly (P < 0.05) improved morphological changes in the islets and β-cells were observed in rats treated with RHT. The data of this study suggest that RHT demonstrates an outstanding antioxidant and anti-diabetic effects in STZ-induced T2D model of rats.

BAT’s specific Micro-RNA or Novel approach for treatment of obesity: A hypothesis

Background: Type 2 Diabetes (T2D) is associated with coronary microvascular dysfunction, which is thought to contribute to compromised diastolic function, ultimately culminating in heart failure with preserved ejection fraction (HFpEF). The molecular mechanisms remain incompletely understood, and no early diagnostics are available. We sought to gain insight into biomarkers and potential mechanisms of microvascular dysfunction in obese mice (db/db) and lean rats (Goto-Kakizaki) pre-clinical models of T2D-associated diastolic dysfunction. Methods: The microRNA (miRNA) content of circulating Extracellular Vesicles (EVs) was assessed in T2D models to identify biomarkers of coronary microvascular dysfunction/rarefaction. The potential source of circulating EV-encapsulated miRNAs was determined, and the mechanisms of induction and the function of candidate miRNAs were assessed in Endothelial Cells (ECs). Results: We found an increase in miR-30d-5p and miR-30e-5p in circulating EVs that coincided with indices of coronary microvascular EC dysfunction (i.e., markers of oxidative stress, DNA damage/senescence) and rarefaction, and preceded echocardiographic evidence of diastolic dysfunction. These miRNAs may serve as biomarkers of coronary microvascular dysfunction as they are upregulated in ECs of the left ventricle of the heart, but not other organs, in db/db mice. Furthermore, the miR-30 family is secreted in EVs from senescent ECs in culture, and ECs with senescent-like characteristics are present in the db/db heart. Assessment of miR-30 target pathways revealed a network of genes involved in fatty acid biosynthesis and metabolism. Over-expression of miR-30e in cultured ECs increased fatty acid β-oxidation and the production of reactive oxygen species and lipid peroxidation while inhibiting the miR-30 family decreased fatty acid β-oxidation. Additionally, miR-30e over-expression synergized with fatty acid exposure to down-regulate the expression of eNOS, a key regulator of microvascular and cardiomyocyte function. Finally, the knock-down of the miR-30 family in db/db mice decreased markers of oxidative stress and DNA damage/senescence in the microvascular endothelium. Conclusion: MiR-30d/e represents early biomarkers and potential therapeutic targets that are indicative of the development of diastolic dysfunction and may reflect altered EC fatty acid metabolism and microvascular dysfunction in the diabetic heart.

Human pancreatic capillaries and nerve fibers persist in type 1 diabetes despite beta cell loss.

The autonomic nervous system regulates pancreatic function. Islet capillaries are essential for the extension of axonal projections into islets, and both of these structures are important for appropriate islet hormone secretion. Because beta cells provide important paracrine cues for islet glucagon secretion and neurovascular development, we postulated that beta cell loss in type 1 diabetes (T1D) would lead to a decline in intraislet capillaries and reduction of islet innervation, possibly contributing to abnormal glucagon secretion. To define morphological characteristics of capillaries and nerve fibers in islets and acinar tissue compartments, we analyzed neurovascular assembly across the largest cohort of T1D and normal individuals studied thus far. Because innervation has been studied extensively in rodent models of T1D, we also compared the neurovascular architecture between mouse and human pancreas and assembled transcriptomic profiles of molecules guiding islet angiogenesis and neuronal development. We found striking interspecies differences in islet neurovascular assembly but relatively modest differences at transcriptome level, suggesting that posttranscriptional regulation may be involved in this process. To determine whether islet neurovascular arrangement is altered after beta cell loss in T1D, we compared pancreatic tissues from non-diabetic, recent-onset T1D (<10-yr duration), and longstanding T1D (>10-yr duration) donors. Recent-onset T1D showed greater islet and acinar capillary density compared to non-diabetic and longstanding T1D donors. Both recent-onset and longstanding T1D had greater islet nerve fiber density compared to non-diabetic donors. We did not detect changes in sympathetic axons in either T1D cohort. Additionally, nerve fibers overlapped with extracellular matrix (ECM), supporting its role in the formation and function of axonal processes. These results indicate that pancreatic capillaries and nerve fibers persist in T1D despite beta cell loss, suggesting that alpha cell secretory changes may be decoupled from neurovascular components.NEW & NOTEWORTHY Defining the neurovascular architecture in the pancreas of individuals with type 1 diabetes (T1D) is crucial to understanding the mechanisms of dysregulated glucagon secretion. In the largest T1D cohort of biobanked tissues analyzed to date, we found that pancreatic capillaries and nerve fibers persist in human T1D despite beta cell loss, suggesting that alpha cell secretory changes may be decoupled from neurovascular components. Because innervation has been studied extensively in rodent T1D models, our studies also provide the first rigorous direct comparisons of neurovascular assembly in mouse and human, indicating dramatic interspecies differences.

Identifying risk factors of developing type 2 diabetes from an adult population with initial prediabetes using a Bayesian network.

It is known that people with prediabetes increase their risk of developing type 2 diabetes (T2D), which constitutes a global public health concern, and it is associated with other diseases such as cardiovascular disease. This study aimed to determine those factors with high influence in the development of T2D once prediabetes has been diagnosed, through a Bayesian network (BN), which can help to prevent T2D. Furthermore, the set of features with the strongest influences on T2D can be determined through the Markov blanket. A BN model for T2D was built from a dataset composed of 12 relevant features of the T2D domain, determining the dependencies and conditional independencies from empirical data in a multivariate context. The structure and parameters were learned with the bnlearn package in R language introducing prior knowledge. The Markov blanket was considered to find those features (variables) which increase the risk of T2D. The BN model established the different relationships among features (variables). Through inference, a high estimated probability value of T2D was obtained when the body mass index (BMI) was instantiated to obesity value, the glycosylated hemoglobin (HbA1c) to more than 6 value, the fatty liver index (FLI) to more than 60 value, physical activity (PA) to no state, and age to 48-62 state. The features increasing T2D in specific states (warning factors) were ranked. The feasibility of BNs in epidemiological studies is shown, in particular, when data from T2D risk factors are considered. BNs allow us to order the features which influence the most the development of T2D. The proposed BN model might be used as a general tool for prevention, that is, to improve the prognosis.

Improvement of Glucose Intolerance in Asian-Type Diabetes Model Mice Using Pentadecyl, Pentadecanoic Acid-Based Triglyceride

Even-chain saturated fatty acid concentrations are associated with an increased risk of coronary heart disease, whereas oddchain saturated fatty acid concentrations, such as pentadecanoic acid (15:0) and heptadecanoic acid (17:0), are associated with a decreased risk. Similarly, even-chain saturated fatty acids are positively associated with type 2 diabetes (T2D), whereas odd-chain saturated fatty acids are thought to be inversely associated with T2D. We purified pentadecyl, pentadecanoic acidbased triglycerides from Aurantiochytrium limacinum, a type of marine microalgae, and demonstrated the effect of pentadecyl on insulin secretion both in vitro and in vivo. Pentadecyl increased the cell viability of immortalized mouse pancreatic beta cells in a dose-dependent manner and induced high glucose-stimulated insulin secretion in the cells. Pancreatic beta cellspecific CDKAL1-deficient mice, a model of Asian-type T2D, were given pentadecyl with a low- or high-fat diet for 9 weeks, and glucose tolerance tests were performed. Pentadecyl improved the glucose intolerance of the mice and decreased the expressions of ER stress-related genes in the islets of the mice. These results suggest that pentadecyl can improve insulin secretion through the reduction of ER stress in patients with Asian-type T2D.