ResearchPad - metabolic-interactions-in-diabetes Default RSS Feed en-us © 2020 Newgen KnowledgeWorks <![CDATA[SUN-LB124 Novel Elisa Assays Demonstrate Specificity of Islet and Intestinal Processing of Proglucagon]]> Circulating proglucagon peptides (PGP) are produced in islet α-cells, enteroendocrine L-cells. Release of PGP is thought to be tissue specific, e.g. α-cells make glucagon and L-cells make GLP-1 through predominant actions of proconvertases 2 and 1/3 (PC2 and PC1/3). However, this dichotomous model has recently been challenged. To address the contribution of the gut and pancreas to plasma PGP we developed 4 novel sandwich ELISA assays and applied them in studies with PGP stimulation from the islet (IV arginine) and intestine (meal). Monoclonal antibodies were raised in mice with genetic ablation of proglucagon transcription. Clones were screened and selected for affinity and specificity, and assays for glucagon, GLP-1, glicentin and oxyntomodulin developed. Eight healthy humans received 5 g arginine intravenously after a 12 hour fast and had blood sampled for 15 minutes; an additional 10 consumed a liquid mixed nutrient meal and prandial blood was taken for 180 minutes. None of the assays registered signal in plasma from proglucagon null mice, and specificity, background and cross-reactivity were acceptable in each. In response to IV arginine plasma glucagon increased 4-fold, and GLP-1 1.5-fold, with significant increases in 15-minute AUC; there was no significant change in either glicentin or oxyntomodulin. In response to meal ingestion there was no change in circulating glucagon, but oxyntomodulin, GLP-1 and glicentin increased 2, 3, and 4-fold respectively. These findings are generally compatible with PC1/3 dominant processing of PGP in the gut, but raise the possibility that α-cells produce both PC2 (glucagon) and PC1/3 (GLP-1) products.

<![CDATA[SUN-662 Praliciguat, a Clinical-Stage Soluble Guanylate Cyclase Stimulator, Improves Lipid Handling and Insulin Sensitivity in Diet-Induced Obese Mice]]> Praliciguat (PRL) is a soluble guanylate cyclase (sGC) stimulator which in animal models distributes broadly to tissues and elicits hemodynamic, anti-inflammatory, anti-fibrotic, and metabolic effects. Here, we assessed metabolic effects of PRL in a mouse diet-induced obesity model.

Six-week-old male C57BL/6N mice were maintained on a low-fat diet (LFD, lean mice) or placed on a 60% high-fat diet (HFD, obese mice). At age 14 weeks, one group of obese mice was maintained on HFD (obese controls) and one group of obese mice was switched to HFD formulated with PRL to achieve a Cmax similar to a 6-mg/kg oral dose (PRL-treated mice). After 38 days of treatment, an oral lipid tolerance test (LTT) was conducted. In a 2nd study under the same dosing paradigm, overnight fasted blood and organs were collected on day 28.

As reported previously (1), compared to obese controls, PRL-treated mice had lower fasting insulin (-28%), HOMA-IR (-26%) and triglycerides (-16%) as well as lower plasma triglycerides AUC after LTT (-34%). Gene expression and phosphorylated proteins associated with insulin pathways were measured in liver, skeletal muscle and white adipose tissue. PRL treatment normalized expression of genes involved in lipid handling (liver Pnpla3, Slc27a1, Lpl; muscle Lipe; white adipose tissue Fdft1, Ppara). Expression of proinflammatory genes (liver Tnf; muscle Ccl2; white adipose tissue Akt1, Icam1) was lower in PRL-treated mice than in obese controls. Liver insulin signaling was assessed by determining pAKT (T308) and pAKT (S473), markers of PI3K pathway activity and pERK, a marker of MAPK pathway activity. Compared to lean mice, pAKT (T308) and pERK were lower in obese controls, whereas pAKT (S473) was similar; PRL-treated mice had higher pAKT (T308) and pAKT (S473) compared to obese controls while pERK was unchanged. In skeletal muscle and white adipose tissue, levels of pVASP, a key mediator of the sGC pathway, were higher in PRL-treated mice than in obese controls.

In summary, PRL improved insulin sensitivity and lipids in diet-induced obese mice by affecting mechanisms of lipid handling, inflammation, and insulin signaling in key tissues associated with metabolism.

1. Author information excluded, 1924-P: Praliciguat, a Clinical-Stage sGC Stimulator, Improves Insulin Sensitivity, Lipid Tolerance, and Energy Utilization in a Mouse Diet-Induced Obesity Model Housed at Thermoneutrality. Diabetes, 2019. 68(Supplement 1): p. 1924-P.

<![CDATA[SUN-663 Dietary Coconut Oil Mitigates Features of Metabolic Syndrome in Obese Females]]> Forty percent of American women are obese and at risk for metabolic syndrome. Coconut oil alters circulating lipid levels and improves glucose homeostasis in lean individuals, yet, whether it can exert these same beneficial effects on cardiometabolic health in obese individuals is unknown. We hypothesized that female pigs fed a high fat diet with 5% coconut oil would have improvements in features of metabolic syndrome (i.e., dyslipidemia) compared to female mini-pigs fed a high fat diet with 5% lard. We fed female pigs 2200 kcal of a control (n=6), 5000 kcal of a lard high fat (WSD; n=5), or 5000 kcal of a coconut oil high fat (COC; n=6) diet for a total of 9 estrous cycles (~ 7.5 months). Fasting blood was collected at the 1st, 7th (C 7), and 9th (C 9) estrous cycle. After C 7, an intravenous glucose tolerance test (IVGTT) was performed. Weights and morphometric measurements were taken weekly. Tissue was collected for histology at C 9. WSD females (15.14 ± 1.85 mg/dL) had a greater increase in fasting glucose as compared to COC (3.51 ± 4.31 mg/dL) and C females (0.45 ± 3.32 mg/dL; p<0.05). COC females tended to be more glucose tolerant (p=0.07) and had lower serum insulin concentrations in response to a glucose bolus (p<0.001) than WSD females. COC (82.6 ± 1.1 kg) and WSD females (85.4 ± 1.0 kg) weighed more (C: 61.9 ± 1.1 kg; p<0.0001) and had larger abdominal circumferences (COC: 122.4 ± 0.8 cm; WSD: 117.4 ± 1.0 cm) than control females (102.6 ± 1.0 cm; p<0.0001). WSD females were the most dyslipidemic, with the greatest increase in triglycerides (C: 0.33 ± 1.5 mg/dL; COC: 7.71 ± 3.0 mg/dL; WSD: 17.25 ± 3.0 mg/dL; p=0.03) and HDL:cholesterol (C: 3.44 ± 0.22; COC: 5.00 ± 0.36; WSD: 6.00 ± 0.42; p=0.05) as compared control and COC females. COC females had increased plasma docosahexaenoic acid (C: -0.128 ± 0.291; COC: 0.262 ± 0.260; WSD: -0.732 ± 0.274; p<0.01) and decreased arachidonic acid (C: 2.418 ± 0.744; COC: -4.561 ± 0.666; WSD: -2.068 ± 0.702; p<0.01). COC females (131.26 ± 10.0 μm) had a decreased average omental adipocyte diameter as compared to WSD females (160.06 ± 10.31 μm; p=0.05). COC females (7.3 ± 0.80 %) had less hepatic lipid accumulation as measured by oil red o stain than WSD females (9.2 ± 1.1 %; p=0.05). These data demonstrate that small amounts of dietary coconut oil, even as a part of a high fat diet, can mitigate features of metabolic syndrome and decrease hepatic and visceral adipose tissue lipid accumulation in obese females.

<![CDATA[SUN-649 Metabolic and Functional Regulation of T Cells by Insulin and Insulin like Growth Factor 1]]> Obesity leads to altered immunity characterized by increased risk of autoimmunity, poor response to infection, and impaired vaccine response. T cells play an important role in this obesity-associated immune response; however, the mechanisms by which T cells are altered in obesity remain unknown. Our goal is to identify nutritionally regulated hormones and cytokines that link whole body nutrition and immunity, and to understand the mechanisms by which such factors can alter T cell response in obesity. To that end, we have identified the hormones insulin and insulin-like growth factor-1 (IGF-1) as potential links between nutritional status and T cell metabolism and function. Insulin is secreted from pancreatic beta cells in response to increasing blood glucose levels, and circulating insulin levels are elevated in obesity due to insulin resistance in metabolic tissues. IGF-1 levels are influenced by protein intake and nutrition status, and free (bioactive) levels of IGF-1 are elevated in obesity. To study the role of insulin and IGF-1 on T cell function and metabolism, we treated activated CD4 T cells with physiologic levels of insulin or IGF-1 in vitro for 24 hours. Treatment of CD4 T cells with insulin or IGF-1 increased glucose uptake, glycolytic metabolism, and mitochondrial metabolism while altering inflammatory cytokine production. In particular, both insulin and IGF-1 decreased IFN-γ production, whereas IGF-1 specifically increased IL-17 production from both bulk activated CD4 T cells and T cells skewed toward a T helper 17 (Th17) phenotype. Using a T cell-specific insulin receptor (IR) conditional knockout mouse, we found that loss of IR signaling decreased glucose uptake and mitochondrial metabolism and increased IFN-γ production by activated T cells. Moreover, IR appears to be required for both insulin and IGF-1 effects on T cells. Lastly, we investigated the CD4 T cell subset-specific expression of both IR and IGF-1 receptor (IGF-1R). We found that each CD4 T cell subset had its own unique expression of both IR and IGF-1R; however Th17 cells had a striking increase in IGF-1R expression compared to the other T cell subsets, indicating a specific role for IGF-1 in promoting inflammation. These findings underscore the ability of the nutritionally-regulated hormones insulin and IGF-1 to modulate CD4 T cell metabolism and function and thereby alter T cell immunity, which has direct clinical relevance in both normal physiology and in obesity.

<![CDATA[SUN-653 Bypassing Skeletal Muscle Lipid Handling Deficiencies as a Therapy for Metabolic Disease]]> Metabolic diseases and their serious sequelae such as non-alcoholic fatty liver disease (NAFLD) pose a substantial clinical burden. It is now well recognized that skeletal muscle is a major site for the metabolism of all major macronutrients, and derangements in these muscle processes significantly contribute to metabolic disease. Studies over the last 15 years have identified the transcription factor Krüppel-like factor 15 (KLF15) as an important regulator and effector of metabolic processes across various tissues, and furthermore, genome-wide studies have identified human KLF15 variants with increased body mass index and diabetes. Given the importance of skeletal muscle in maintaining metabolic homeostasis, we generated a skeletal muscle specific KLF15 knockout (K15-SKO) mouse to study the role of skeletal muscle KLF15 in regulating systemic metabolism. We found that this animal is prone to developing obesity and insulin resistance at baseline, a phenotype that is greatly exacerbated in response to high fat diet (HFD). Strikingly, K15-SKO mice show a propensity toward developing NAFLD, as demonstrated by increased micro- and macrovesicular steatosis, hepatocellular ballooning, increased hepatic fatty acid and triglyceride deposition, and elevated Cd36 expression. A potential cause of NAFLD is the accumulation of excess lipids and lipid intermediates due to defects in the lipid flux pathway in extrahepatic tissues. Indeed, we see defects in the expression of genes involved in the carnitine shuttle and a paucity of long-chain acylcarnitines in K15-SKO skeletal muscle. Furthermore, RNA sequencing of skeletal muscle from K15-SKO mice shows downregulation in a number of pathways involved in lipid handling. This indicates that KLF15 serves as a novel extrahepatic molecular regulator of hepatic health. It has been previously shown that a diet rich in short-chain fatty acids (SCFA) can bypass defects in lipid handling and ultimately improve metabolic health. To explore this therapeutic avenue, we gave K15-SKO mice either normal chow (NC) or a SCFA-rich diet for 7 weeks. We observed decreased weight gain and improved glucose homeostasis in SCFA-rich diet fed mice. In addition to being a preventative strategy, SCFA-rich diets may also serve as a potential therapy to rescue from metabolic disease. To this end, we gave K15-SKO mice HFD for 5 weeks followed by 7 weeks of either NC or SCFA-rich diet. We observed that providing SCFAs can improve metabolic health and ameliorate the phenotype seen due to defects in skeletal muscle lipid handling: mice given SCFA-rich diet following HFD had significantly decreased weight gain and improved insulin sensitivity. These studies demonstrate that skeletal muscle KLF15 serves as an important regulator of lipid flux and hepatic health, and that SCFA-rich diets are a promising candidate for metabolic disease resultant of impaired lipid handling.

<![CDATA[SUN-658 CHL1 Increases Insulin Secretion&amp;Negatively Regulates the Poliferation of Pancreatic β Cell]]> CHL1 Increases Insulin Secretion & Negatively Regulates The Poliferation Of Pancreatic β Cell

Objective: CHL1 belongs to neural recognition molecules of the immunoglobulin superfamily, is mainly expressed in the nervous system. CHL1 is involved in neuronal migration, axonal growth, and dendritic projection. RNA sequencing of single human islet cells confirmed that CHL1 had an expression difference in β cells of type 2 diabetes and healthy controls. However, whether CHL1 gene regulates islet function remained to be explored.

Methods: PCR and Western Blot were applied to investigate the tissue distribution of CHL1 in wild-type C57BL/6J mice. The islet expression of CHL1 gene was observed in pancreatic islets of NOD mice and high-fat-diet C57BL/6J mice of different ages. MIN6 cells with siRNA to silence CHL1 or with lentivirus to overexpress CHL1 were constructed. Effects of the gene on proliferation, apoptosis, cell cycle and insulin secretion were determined by using CCK8, EdU, TUNEL, AV/PI, GSIS, electron microscopy and flow cytometry.

Results: CHL1 was localized on the cell membrane and expressed in the nervous system, islet of pancreas and gastrointestinal tract. CHL1 was hypoexpressed in the pancreatic islets of obese mice, hyperexpressed in the pancreatic islets of NOD mice and in vitro after treated with cytokines. After silencing CHL1 in MIN6 cells, insulin secretion decreased in 20 mM glucose with down-regulation of INS1, SLC2A2 gene, and transmission electron microscope showed the number of insulin secretary granules <50nm from the cell membrane was significantly reduced. Silencing of CHL1 in MIN6 cells induced cell proliferation, reduced apoptosis rate, prolonged the S phase of cell cycle and shortened the G1 phase with downregulated expression of p21, p53 and up-regulated expression of cyclin D1, opposite results were found in CHL1 over-expressing MIN6 cells. Proliferation induced by silencing of CHL1 was inhibited by ERK inhibitor (PD98059), which indicates that ERK pathway is essential for signaling by these molecules in pancreatic β cell.

Conclusion: The expression of CHL1 gene was significantly decreased in the pancreatic islets of obese mice induced by high-fat diet. The low expression of CHL1 gene promotes the proliferation of MIN6 cells through the ERK pathway and affect cell cycle through the p53 pathway. This may be one of the mechanisms that pancreatic β cells compensatory hyperplasia in the stage of obesity-induced pre-diabetes.

<![CDATA[SUN-650 Body Composition Assessment in Clinical Practice: Use in Rheumatoid Arthritis and Hypogonadism]]> BACKGROUND: DXA is an accessible, non-invasive method, also used for body composition assessment, standing out for regional composition analysis. In clinical practice, the analysis of body composition is relevant by differentiating lean (fat-free) mass from fat mass. The higher the fat to lean mass ratio, the greater the obesity-related comorbidities.


Case 1: A 22-year-old male, BMI 21kg/m2, with rheumatoid arthritis (RA) and on chronic glucocorticoid (GC) performed a DXA to evaluated body composition. The first analysis, during GC use, showed 26.1% fat (14.6kg) despite the low BMI. The patient, evolved stable from RA, and was able to stay out of GC for 2 years, with no other interventions. A new DXA showed a decrease in fat percentage to 12.6% (6.2kg), a reduction in total body weight (-7kg) and an increase in lean mass (+1.2kg). Within 16 months of GC reintroduction, the fat percentage increased up to 36.8% (23.8kg), the total weight increased by 15.6kg and the lean mass decreased by 2.1kg.

Case 2: A 40-year-old male with hypogonadism showed 37% fat (33.8kg) on ​​first DXA evaluation. Testosterone replacement was started, and a new DXA was performed after 10 weeks, and although the total weight increased by 3.1kg, there was a decrease in fat mass to 33.5% (31.6kg) and an increase of 5.3kg in lean mass. After 3 years, there was a reduction to 27.1% of fat (24.5kg) and, after 4 years of therapy initiation, the percentage of fat was 26.9% (24.5kg). There was no change in diet or exercise.


The exposed cases highlight the importance of body composition assessment in patients with conditions that interferes with energy metabolism. The patient on chronic GC use, after medication withdrawal, presented a significant decrease in fat mass, more pronounced in the android percentage. The reintroduction of the CG showed an increase in fat percentage, with android predominance. The patient with hypogonadism, in the second evaluation performed with only 10 weeks of treatment with testosterone, evolved with a reduction in fat mass associated with an increase in lean mass, besides a reduction in the android percentage.

The reported cases illustrate everyday clinical situations in which disease vs. treatment significantly changes body composition. Assessment of body composition is essential in patients exposed to conditions that interfere with energy metabolism since obesity is associated with chronic comorbidities and cardiovascular outcomes.

<![CDATA[SUN-672 SGLT2 Inhibitor Reduces Hyperinsulinemia and Restores Pulsatile Growth Hormone Secretion in Obese MC4RKO Mice]]> Insulin and growth hormone (GH) are crucial counter-regulatory hormones in regulating glucose and lipid metabolisms. Insulin promotes fat storage, while GH promotes lipolysis and fat oxidation. In obese individuals, reduced GH secretion (hyposomatotropism) and increased insulin secretion (hyperinsulinemia) co-exist. The imbalance of these two hormones exacerbates fat accumulation. Therapeutic approaches to correct such hormonal imbalance in obesity are limited. The sodium/glucose cotransporter 2 inhibitor (SGLT2i), which promotes urinary glucose excretion, is a novel drug for overt type 2 diabetes (T2D). However, little is known about its efficacy in obese individuals without T2D in the clinic, in particular with hormonal imbalance. By applying SGLT2i (dapagliflozin, 1 mg/kg/d for 10 weeks) to a hyperphagic obese melanocortin 4 receptor knockout (MC4RKO) mouse model, we observed a significant reduction of hyperinsulinemia (fasting: 1.36±0.19 vs. 4.93±1.04 ng/ml, p<0.01; fed: 9.50±3.37 vs. 31.11±5.85 ng/ml, p<0.05, n=8) and restored pulsatile GH secretion without changing secretion pattern (pulsatile GH: 185.3±18.37 vs. 56.28±13.22 ng/ml per 6h, p<0.001; GH mass per secretion pulse: 50.31±8.20 vs. 15.55±3.18 ng/ml, p<0.01; number of secretory pulse per 6h: 3.71±0.29 vs. 3.57±0.43, p=0.78, n=8) as early as 4 weeks after the initiation of the treatment. Lipolysis and lipid oxidation-related gene expression levels were increased by SGLT2i treatment, whereas lipogenesis and inflammation gene expression levels were reduced, leading to decreased whole-body fat mass. Following the treatment, glucose tolerance and insulin sensitivity were both improved. Although a null effect was observed in food intake and daily activity, the treatment significantly promoted lipid usage and shifted energy metabolism towards negative energy balance. In conclusion, 10-week SGLT2i treatment improved glucose and lipid metabolisms in the hyperphagic obese MC4RKO mice. Such improvement occurs alongside reduced hyperinsulinemia and restored pulsatile GH secretion. This work provides insights for the potential use of SGLT2i in obese individuals prior to overt T2D. The final version of this work is published (1).

Acknowledgements: grant (NHMRC, University of Queensland) and scholarship (CSC and UQ International scholarship)

Reference: (1) Huang, Zhengxiang, et al. “Dapagliflozin restores insulin and growth hormone secretion in obese mice.” Journal of Endocrinology 245.1 (2020): 1-12.

Unless otherwise noted, all abstracts presented at ENDO are embargoed until the date and time of presentation. For oral presentations, the abstracts are embargoed until the session begins. Abstracts presented at a news conference are embargoed until the date and time of the news conference. The Endocrine Society reserves the right to lift the embargo on specific abstracts that are selected for promotion prior to or during ENDO.

<![CDATA[SUN-LB121 Nifedipine Worsens Glucose Tolerance in C57BL/6J Mice Exposed to Intermittent Hypoxia]]> <![CDATA[SUN-LB118 Mice With Skeletal Muscle-Specific DRP1 Deficiency Are Resistant to Obesity and Diabetes Induced by a High Fat Diet]]> <![CDATA[SUN-651 Murine Cecal Ligation and Puncture (CLP) Perturbs Phosphorylation of Insulin Receptor Substrate 2 (IRS-2)]]> <![CDATA[SUN-669 The G209R Mutant Mouse as a Model for Human PCSK1 Polyendocrinopathy]]> <![CDATA[SUN-657 The Effect of Simvastatin on Glucose Metabolism in Primary Human Muscle Cells]]>


Statin use, especially treatment with simvastatin, is associated with impaired insulin secretion and whole-body insulin sensitivity, and increased risk for T2D. Here, we investigated the direct effects of lactone- and acid-forms of simvastatin on glucose metabolism in primary human skeletal muscle cells. Exposure of human myotubes to lactone-form simvastatin for 48 h increased glucose uptake and glucose incorporation into glycogen, whereas the acid-form did not affect glucose uptake and decreased glucose incorporation into glycogen. These metabolic actions were accompanied by changes in insulin signaling, as phosphorylation of AS160 and GSK3β was upregulated with lactone-, but not with acid-form simvastatin. Exposure to both lactone and acid-forms of simvastatin led to a decrease in glycolysis and glycolytic capacity, as well as to a decrease in mitochondrial respiration and ATP production. Collectively these data indicate that lactone- and acid forms of simvastatin exhibit differences such that lactone-form increases, and acid-form impairs glucose incorporation into glycogen. Exposure to either form of simvastatin, however, impairs glycolysis and mitochondrial oxidative metabolism in human skeletal muscle cells.

<![CDATA[SUN-LB119 Role of HNF4a Isoforms in the Carbohydrate/Lipid Switch in the Liver and Responsiveness to AMPK]]> <![CDATA[SUN-668 Elevated Osmolal Gap in Long-Term Complication of Type 2 Diabetes]]> <![CDATA[SUN-652 Progesterone Receptor Membrane Component 1 Suppresses Type II Diabetes (T2D) Progression via Induced Insulin Signaling in Muscle]]> <![CDATA[SUN-660 Appetite Suppressing Effects of Glucoregulatory Chimeric Peptides Devoid of Nausea]]> <![CDATA[SUN-654 Dynamic and Regional Variation of Pancreatic Innervation in Diabetes]]> <![CDATA[SUN-667 Hyperinsulinemia Suppresses Hepatic Autophagy at Late Sepsis in an mTOR-Dependent Transcriptional Regulation]]> <![CDATA[SUN-670 P300 and CBP Are Necessary for Skeletal Muscle Insulin-Stimulated Glucose Uptake]]>