1321. A Phenotypic Screen Identifies Calcium Overload as a Key Mechanism of β-Cell Glucolipotoxicity.
作者: Jennifer Vogel.;Jianning Yin.;Liansheng Su.;Sharon X Wang.;Richard Zessis.;Sena Fowler.;Chun-Hao Chiu.;Aaron C Wilson.;Amy Chen.;Frederic Zecri.;Gordon Turner.;Thomas M Smith.;Brian DeChristopher.;Heming Xing.;Deborah M Rothman.;Xinming Cai.;Alina Berdichevsky.
来源: Diabetes. 2020年69卷5期1032-1041页
Type 2 diabetes (T2D) is caused by loss of pancreatic β-cell mass and failure of the remaining β-cells to deliver sufficient insulin to meet demand. β-Cell glucolipotoxicity (GLT), which refers to combined, deleterious effects of elevated glucose and fatty acid levels on β-cell function and survival, contributes to T2D-associated β-cell failure. Drugs and mechanisms that protect β-cells from GLT stress could potentially improve metabolic control in patients with T2D. In a phenotypic screen seeking low-molecular-weight compounds that protected β-cells from GLT, we identified compound A that selectively blocked GLT-induced apoptosis in rat insulinoma cells. Compound A and its optimized analogs also improved viability and function in primary rat and human islets under GLT. We discovered that compound A analogs decreased GLT-induced cytosolic calcium influx in islet cells, and all measured β-cell-protective effects correlated with this activity. Further studies revealed that the active compound from this series largely reversed GLT-induced global transcriptional changes. Our results suggest that taming cytosolic calcium overload in pancreatic islets can improve β-cell survival and function under GLT stress and thus could be an effective strategy for T2D treatment.
1322. Obesity Reduces Maternal Blood Triglyceride Concentrations by Reducing Angiopoietin-Like Protein 4 Expression in Mice.
作者: Liping Qiao.;Shwetha K Shetty.;Kathryn M Spitler.;Jean-Sebastien Wattez.;Brandon S J Davies.;Jianhua Shao.
来源: Diabetes. 2020年69卷6期1100-1109页
To ensure fetal lipid supply, maternal blood triglyceride (TG) concentrations are robustly elevated during pregnancy. Interestingly, a lower increase in maternal blood TG concentrations has been observed in some obese mothers. We have shown that high-fat (HF) feeding during pregnancy significantly reduces maternal blood TG levels. Therefore, we performed this study to investigate if and how obesity alters maternal blood TG levels. Maternal obesity was established by prepregnant HF (ppHF) feeding, which avoided the dietary effect during pregnancy. We found not only that maternal blood TG concentrations in ppHF dams were remarkably lower than in control dams but also that the TG peak occurred earlier during gestation. Hepatic TG production and intestinal TG absorption were unchanged in ppHF dams, but systemic lipoprotein lipase (LPL) activity was increased, suggesting that increased blood TG clearance contributes to the decreased blood TG concentrations in ppHF dams. Although significantly higher levels of UCP1 protein were observed in interscapular brown adipose tissue (iBAT) of ppHF dams, Ucp1 gene deletion did not restore blood TG concentrations in ppHF dams. Expression of the angiopoietin-like protein 4 (ANGPTL4), a potent endogenous LPL inhibitor, was significantly increased during pregnancy. However, the pregnancy-induced elevation of blood TG was almost abolished in Angptl4-/- dams. Compared with control dams, Angptl4 mRNA levels were significantly lower in iBAT, gonadal white adipose tissue, and livers of ppHF dams. Importantly, ectopic overexpression of ANGPTL4 restored maternal blood TG concentrations in ppHF dams. Together, these results indicate that ANGPTL4 plays a vital role in increasing maternal blood TG concentrations during pregnancy. Obesity impairs the rise of maternal blood TG concentrations by reducing ANGPTL4 expression in mice.
1323. Risk Factors for Diabetic Peripheral Neuropathy and Cardiovascular Autonomic Neuropathy in the Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications (DCCT/EDIC) Study.
作者: Barbara H Braffett.;Rose A Gubitosi-Klug.;James W Albers.;Eva L Feldman.;Catherine L Martin.;Neil H White.;Trevor J Orchard.;Maria Lopes-Virella.;John M Lachin.;Rodica Pop-Busui.; .
来源: Diabetes. 2020年69卷5期1000-1010页
The Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications (DCCT/EDIC) study demonstrated that intensive glucose control reduced the risk of developing diabetic peripheral neuropathy (DPN) and cardiovascular autonomic neuropathy (CAN). We evaluated multiple risk factors and phenotypes associated with DPN and CAN in this large, well-characterized cohort of participants with type 1 diabetes, followed for >23 years. DPN was defined by symptoms, signs, and nerve conduction study abnormalities in ≥2 nerves; CAN was assessed using standardized cardiovascular reflex tests. Generalized estimating equation models assessed the association of DPN and CAN with individual risk factors measured repeatedly. During DCCT/EDIC, 33% of participants developed DPN and 44% CAN. Higher mean HbA1c was the most significant risk factor for DPN, followed by older age, longer duration, greater height, macroalbuminuria, higher mean pulse rate, β-blocker use, and sustained albuminuria. The most significant risk factor for CAN was older age, followed by higher mean HbA1c, sustained albuminuria, longer duration of type 1 diabetes, higher mean pulse rate, higher mean systolic blood pressure, β-blocker use, estimated glomerular filtration rate <60 mL/min/1.73 m2, higher most recent pulse rate, and cigarette smoking. These findings identify risk factors and phenotypes of participants with diabetic neuropathy that can be used in the design of new interventional trials and for personalized approaches to neuropathy prevention.
1324. Novel Detection and Restorative Levodopa Treatment for Preclinical Diabetic Retinopathy.
作者: Cara T Motz.;Kyle C Chesler.;Rachael S Allen.;Katie L Bales.;Lukas M Mees.;Andrew J Feola.;April Y Maa.;Darin E Olson.;Peter M Thule.;P Michael Iuvone.;Andrew M Hendrick.;Machelle T Pardue.
来源: Diabetes. 2020年69卷7期1518-1527页
Diabetic retinopathy (DR) is diagnosed clinically by directly viewing retinal vascular changes during ophthalmoscopy or through fundus photographs. However, electroretinography (ERG) studies in humans and rodents have revealed that retinal dysfunction is demonstrable prior to the development of visible vascular defects. Specifically, delays in dark-adapted ERG oscillatory potential (OP) implicit times in response to dim-flash stimuli (<-1.8 log cd · s/m2) occur prior to clinically recognized DR. Animal studies suggest that retinal dopamine deficiency underlies these early functional deficits. In this study, we randomized individuals with diabetes, without clinically detectable retinopathy, to treatment with either low- or high-dose Sinemet (levodopa plus carbidopa) for 2 weeks and compared their ERG findings with those of control subjects (no diabetes). We assessed dim-flash-stimulated OP delays using a novel handheld ERG system (RETeval) at baseline and 2 and 4 weeks. RETeval recordings identified significant OP implicit time delays in individuals with diabetes without retinopathy compared with age-matched control subjects (P < 0.001). After 2 weeks of Sinemet treatment, OP implicit times were restored to control values, and these improvements persisted even after a 2-week washout. We conclude that detection of dim-flash OP delays could provide early detection of DR and that Sinemet treatment may reverse retinal dysfunction.
1325. L-Cell Differentiation Is Induced by Bile Acids Through GPBAR1 and Paracrine GLP-1 and Serotonin Signaling.
作者: Mari Lilith Lund.;Giovanni Sorrentino.;Kristoffer Lihme Egerod.;Chantal Kroone.;Brynjulf Mortensen.;Filip Krag Knop.;Frank Reimann.;Fiona M Gribble.;Daniel J Drucker.;Eelco J P de Koning.;Kristina Schoonjans.;Fredrik Bäckhed.;Thue W Schwartz.;Natalia Petersen.
来源: Diabetes. 2020年69卷4期614-623页
Glucagon-like peptide 1 (GLP-1) mimetics are effective drugs for treatment of type 2 diabetes, and there is consequently extensive interest in increasing endogenous GLP-1 secretion and L-cell abundance. Here we identify G-protein-coupled bile acid receptor 1 (GPBAR1) as a selective regulator of intestinal L-cell differentiation. Lithocholic acid and the synthetic GPBAR1 agonist, L3740, selectively increased L-cell density in mouse and human intestinal organoids and elevated GLP-1 secretory capacity. L3740 induced expression of Gcg and transcription factors Ngn3 and NeuroD1 L3740 also increased the L-cell number and GLP-1 levels and improved glucose tolerance in vivo. Further mechanistic examination revealed that the effect of L3740 on L cells required intact GLP-1 receptor and serotonin 5-hydroxytryptamine receptor 4 (5-HT4) signaling. Importantly, serotonin signaling through 5-HT4 mimicked the effects of L3740, acting downstream of GLP-1. Thus, GPBAR1 agonists and other powerful GLP-1 secretagogues facilitate L-cell differentiation through a paracrine GLP-1-dependent and serotonin-mediated mechanism.
1326. n-3 Fatty Acid and Its Metabolite 18-HEPE Ameliorate Retinal Neuronal Cell Dysfunction by Enhancing Müller BDNF in Diabetic Retinopathy.
作者: Ayana Suzumura.;Hiroki Kaneko.;Yasuhito Funahashi.;Kei Takayama.;Masatoshi Nagaya.;Seina Ito.;Toshiaki Okuno.;Toshiaki Hirakata.;Norie Nonobe.;Keiko Kataoka.;Hideyuki Shimizu.;Rina Namba.;Kazuhisa Yamada.;Fuxiang Ye.;Yoko Ozawa.;Takehiko Yokomizo.;Hiroko Terasaki.
来源: Diabetes. 2020年69卷4期724-735页
Diabetic retinopathy (DR) is a widespread vision-threatening disease, and neuroretinal abnormality should be considered as an important problem. Brain-derived neurotrophic factor (BDNF) has recently been considered as a possible treatment to prevent DR-induced neuroretinal damage, but how BDNF is upregulated in DR remains unclear. We found an increase in hydrogen peroxide (H2O2) in the vitreous of patients with DR. We confirmed that human retinal endothelial cells secreted H2O2 by high glucose, and H2O2 reduced cell viability of MIO-M1, Müller glia cell line, PC12D, and the neuronal cell line and lowered BDNF expression in MIO-M1, whereas BDNF administration recovered PC12D cell viability. Streptozocin-induced diabetic rats showed reduced BDNF, which is mainly expressed in the Müller glia cell. Oral intake of eicosapentaenoic acid ethyl ester (EPA-E) ameliorated BDNF reduction and oscillatory potentials (OPs) in electroretinography (ERG) in DR. Mass spectrometry revealed an increase in several EPA metabolites in the eyes of EPA-E-fed rats. In particular, an EPA metabolite, 18-hydroxyeicosapentaenoic acid (18-HEPE), induced BDNF upregulation in Müller glia cells and recovery of OPs in ERG. Our results indicated diabetes-induced oxidative stress attenuates neuroretinal function, but oral EPA-E intake prevents retinal neurodegeneration via BDNF in Müller glia cells by increasing 18-HEPE in the early stages of DR.
1327. Longitudinal Metabolome-Wide Signals Prior to the Appearance of a First Islet Autoantibody in Children Participating in the TEDDY Study.
作者: Qian Li.;Hemang Parikh.;Martha D Butterworth.;Åke Lernmark.;William Hagopian.;Marian Rewers.;Jin-Xiong She.;Jorma Toppari.;Anette-G Ziegler.;Beena Akolkar.;Oliver Fiehn.;Sili Fan.;Jeffrey P Krischer.; .
来源: Diabetes. 2020年69卷3期465-476页
Children at increased genetic risk for type 1 diabetes (T1D) after environmental exposures may develop pancreatic islet autoantibodies (IA) at a very young age. Metabolic profile changes over time may imply responses to exposures and signal development of the first IA. Our present research in The Environmental Determinants of Diabetes in the Young (TEDDY) study aimed to identify metabolome-wide signals preceding the first IA against GAD (GADA-first) or against insulin (IAA-first). We profiled metabolomes by mass spectrometry from children's plasma at 3-month intervals after birth until appearance of the first IA. A trajectory analysis discovered each first IA preceded by reduced amino acid proline and branched-chain amino acids (BCAAs), respectively. With independent time point analysis following birth, we discovered dehydroascorbic acid (DHAA) contributing to the risk of each first IA, and γ-aminobutyric acid (GABAs) associated with the first autoantibody against insulin (IAA-first). Methionine and alanine, compounds produced in BCAA metabolism and fatty acids, also preceded IA at different time points. Unsaturated triglycerides and phosphatidylethanolamines decreased in abundance before appearance of either autoantibody. Our findings suggest that IAA-first and GADA-first are heralded by different patterns of DHAA, GABA, multiple amino acids, and fatty acids, which may be important to primary prevention of T1D.
1328. DLL1- and DLL4-Mediated Notch Signaling Is Essential for Adult Pancreatic Islet Homeostasis.
作者: Marina Rubey.;Nirav Florian Chhabra.;Daniel Gradinger.;Adrián Sanz-Moreno.;Heiko Lickert.;Gerhard K H Przemeck.;Martin Hrabě de Angelis.
来源: Diabetes. 2020年69卷5期915-926页
Genes of the Notch signaling pathway are expressed in different cell types and organs at different time points during embryonic development and adulthood. The Notch ligand Delta-like 1 (DLL1) controls the decision between endocrine and exocrine fates of multipotent progenitors in the developing pancreas, and loss of Dll1 leads to premature endocrine differentiation. However, the role of Delta-Notch signaling in adult tissue homeostasis is not well understood. Here, we describe the spatial expression pattern of Notch pathway components in adult murine pancreatic islets and show that DLL1 and DLL4 are specifically expressed in β-cells, whereas JAGGED1 is expressed in α-cells. We show that mice lacking both DLL1 and DLL4 in adult β-cells display improved glucose tolerance, increased glucose-stimulated insulin secretion, and hyperglucagonemia. In contrast, overexpression of the intracellular domain of DLL1 in adult murine pancreatic β-cells results in impaired glucose tolerance and reduced insulin secretion, both in vitro and in vivo. These results suggest that Notch ligands play specific roles in the adult pancreas and highlight a novel function of the Delta/Notch pathway in β-cell insulin secretion.
1329. Rare Genetic Variants of Large Effect Influence Risk of Type 1 Diabetes.
作者: Vincenzo Forgetta.;Despoina Manousaki.;Roman Istomine.;Stephanie Ross.;Marie-Catherine Tessier.;Luc Marchand.;Min Li.;Hui-Qi Qu.;Jonathan P Bradfield.;Struan F A Grant.;Hakon Hakonarson.; .;Andrew D Paterson.;Ciriaco Piccirillo.;Constantin Polychronakos.;J Brent Richards.
来源: Diabetes. 2020年69卷4期784-795页
Most replicated genetic determinants for type 1 diabetes are common (minor allele frequency [MAF] >5%). We aimed to identify novel rare or low-frequency (MAF <5%) single nucleotide polymorphisms with large effects on risk of type 1 diabetes. We undertook deep imputation of genotyped data followed by genome-wide association testing and meta-analysis of 9,358 type 1 diabetes case and 15,705 control subjects from 12 European cohorts. Candidate variants were replicated in a separate cohort of 4,329 case and 9,543 control subjects. Our meta-analysis identified 27 independent variants outside the MHC, among which 3 were novel and had MAF <5%. Three of these variants replicated with Preplication < 0.05 and Pcombined < Pdiscovery In silico analysis prioritized a rare variant at 2q24.3 (rs60587303 [C], MAF 0.5%) within the first intron of STK39, with an effect size comparable with those of common variants in the INS and PTPN22 loci (combined [from the discovery and replication cohorts] estimate of odds ratio [ORcombined] 1.97, 95% CI 1.58-2.47, Pcombined = 2.9 × 10-9). Pharmacological inhibition of Stk39 activity in primary murine T cells augmented effector responses through enhancement of interleukin 2 signaling. These findings provide insight into the genetic architecture of type 1 diabetes and have identified rare variants having a large effect on disease risk.
1330. Lamin C Counteracts Glucose Intolerance in Aging, Obesity, and Diabetes Through β-Cell Adaptation.
作者: Marion de Toledo.;Isabel C Lopez-Mejia.;Patricia Cavelier.;Marine Pratlong.;Célia Barrachina.;Xavier Gromada.;Jean-Sébastien Annicotte.;Jamal Tazi.;Carine Chavey.
来源: Diabetes. 2020年69卷4期647-660页
Aging-dependent changes in tissue function are associated with the development of metabolic diseases. However, the molecular connections linking aging, obesity, and diabetes remain unclear. Lamin A, lamin C, and progerin, products of the Lmna gene, have antagonistic functions on energy metabolism and life span. Lamin C, albeit promoting obesity, increases life span, suggesting that this isoform is crucial for maintaining healthy conditions under metabolic stresses. Because β-cell loss during obesity or aging leads to diabetes, we investigated the contribution of lamin C to β-cell function in physiopathological conditions. We demonstrate that aged lamin C only-expressing mice (LmnaLCS/LCS ) become obese but remain glucose tolerant due to adaptive mechanisms including increased β-cell mass and insulin secretion. Triggering diabetes in young mice revealed that LmnaLCS/LCS animals normalize their fasting glycemia by both increasing insulin secretion and regenerating β-cells. Genome-wide analyses combined to functional analyses revealed an increase of mitochondrial biogenesis and global translational rate in LmnaLCS/LCS islets, two major processes involved in insulin secretion. Altogether, our results demonstrate for the first time that the sole expression of lamin C protects from glucose intolerance through a β-cell-adaptive transcriptional program during metabolic stresses, highlighting Lmna gene processing as a new therapeutic target for diabetes treatment.
1331. The Limited Role of Glucagon for Ketogenesis During Fasting or in Response to SGLT2 Inhibition.
作者: Megan E Capozzi.;Reilly W Coch.;Jepchumba Koech.;Inna I Astapova.;Jacob B Wait.;Sara E Encisco.;Jonathan D Douros.;Kimberly El.;Brian Finan.;Kyle W Sloop.;Mark A Herman.;David A D'Alessio.;Jonathan E Campbell.
来源: Diabetes. 2020年69卷5期882-892页
Glucagon is classically described as a counterregulatory hormone that plays an essential role in the protection against hypoglycemia. In addition to its role in the regulation of glucose metabolism, glucagon has been described to promote ketosis in the fasted state. Sodium-glucose cotransporter 2 inhibitors (SGLT2i) are a new class of glucose-lowering drugs that act primarily in the kidney, but some reports have described direct effects of SGLT2i on α-cells to stimulate glucagon secretion. Interestingly, SGLT2 inhibition also results in increased endogenous glucose production and ketone production, features common to glucagon action. Here, we directly test the ketogenic role of glucagon in mice, demonstrating that neither fasting- nor SGLT2i-induced ketosis is altered by interruption of glucagon signaling. Moreover, any effect of glucagon to stimulate ketogenesis is severely limited by its insulinotropic actions. Collectively, our data suggest that fasting-associated ketosis and the ketogenic effects of SGLT2 inhibitors occur almost entirely independent of glucagon.
1332. Perivascular Adipose Tissue Controls Insulin-Stimulated Perfusion, Mitochondrial Protein Expression, and Glucose Uptake in Muscle Through Adipomuscular Arterioles.
作者: Alexander H Turaihi.;Erik H Serné.;Carla F M Molthoff.;Jasper J Koning.;Jaco Knol.;Hans W Niessen.;Marie Jose T H Goumans.;Erik M van Poelgeest.;John S Yudkin.;Yvo M Smulders.;Connie R Jimenez.;Victor W M van Hinsbergh.;Etto C Eringa.
来源: Diabetes. 2020年69卷4期603-613页
Insulin-mediated microvascular recruitment (IMVR) regulates delivery of insulin and glucose to insulin-sensitive tissues. We have previously proposed that perivascular adipose tissue (PVAT) controls vascular function through outside-to-inside communication and through vessel-to-vessel, or "vasocrine," signaling. However, direct experimental evidence supporting a role of local PVAT in regulating IMVR and insulin sensitivity in vivo is lacking. Here, we studied muscles with and without PVAT in mice using combined contrast-enhanced ultrasonography and intravital microscopy to measure IMVR and gracilis artery diameter at baseline and during the hyperinsulinemic-euglycemic clamp. We show, using microsurgical removal of PVAT from the muscle microcirculation, that local PVAT depots regulate insulin-stimulated muscle perfusion and glucose uptake in vivo. We discovered direct microvascular connections between PVAT and the distal muscle microcirculation, or adipomuscular arterioles, the removal of which abolished IMVR. Local removal of intramuscular PVAT altered protein clusters in the connected muscle, including upregulation of a cluster featuring Hsp90ab1 and Hsp70 and downregulation of a cluster of mitochondrial protein components of complexes III, IV, and V. These data highlight the importance of PVAT in vascular and metabolic physiology and are likely relevant for obesity and diabetes.
1333. Insulin-Deficient Diabetic Condition Upregulates the Insulin-Secreting Capacity of Human Induced Pluripotent Stem Cell-Derived Pancreatic Endocrine Progenitor Cells After Implantation in Mice.
作者: Taisuke Mochida.;Hikaru Ueno.;Noriko Tsubooka-Yamazoe.;Hideyuki Hiyoshi.;Ryo Ito.;Hirokazu Matsumoto.;Taro Toyoda.
来源: Diabetes. 2020年69卷4期634-646页
The host environment is a crucial factor for considering the transplant of stem cell-derived immature pancreatic cells in patients with type 1 diabetes. Here, we investigated the effect of insulin (INS)-deficient diabetes on the fate of immature pancreatic endocrine cell grafts and the underlying mechanisms. Human induced pluripotent stem cell-derived pancreatic endocrine progenitor cells (EPCs), which contained a high proportion of chromogranin A+ NK6 homeobox 1+ cells and very few INS+ cells, were used. When the EPCs were implanted under the kidney capsule in immunodeficient mice, INS-deficient diabetes accelerated increase in plasma human C-peptide, a marker of graft-derived INS secretion. The acceleration was suppressed by INS infusion but not affected by partial attenuation of hyperglycemia by dapagliflozin, an INS-independent glucose-lowering agent. Immunohistochemical analyses indicated that the grafts from diabetic mice contained more endocrine cells including proliferative INS-producing cells compared with that from nondiabetic mice, despite no difference in whole graft mass between the two groups. These data suggest that INS-deficient diabetes upregulates the INS-secreting capacity of EPC grafts by increasing the number of endocrine cells including INS-producing cells without changing the graft mass. These findings provide useful insights into postoperative diabetic care for cell therapy using stem cell-derived pancreatic cells.
1334. Comprehensive Glycomic Analysis Reveals That Human Serum Albumin Glycation Specifically Affects the Pharmacokinetics and Efficacy of Different Anticoagulant Drugs in Diabetes.
作者: Hongyan Qiu.;Lan Jin.;Jian Chen.;Min Shi.;Feng Shi.;Mansen Wang.;Daoyuan Li.;Xiaohui Xu.;Xinhuan Su.;Xianlun Yin.;Wenhua Li.;Xiaoming Zhou.;Robert J Linhardt.;Zhe Wang.;Lianli Chi.;Qunye Zhang.
来源: Diabetes. 2020年69卷4期760-770页
Long-term hyperglycemia in patients with diabetes leads to human serum albumin (HSA) glycation, which may impair HSA function as a transport protein and affect the therapeutic efficacy of anticoagulants in patients with diabetes. In this study, a novel mass spectrometry approach was developed to reveal the differences in the profiles of HSA glycation sites between patients with diabetes and healthy subjects. K199 was the glycation site most significantly changed in patients with diabetes, contributing to different interactions of glycated HSA and normal HSA with two types of anticoagulant drugs, heparin and warfarin. An in vitro experiment showed that the binding affinity to warfarin became stronger when HSA was glycated, while HSA binding to heparin was not significantly influenced by glycation. A pharmacokinetic study showed a decreased level of free warfarin in the plasma of diabetic rats. A preliminary retrospective clinical study also revealed that there was a statistically significant difference in the anticoagulant efficacy between patients with diabetes and patients without diabetes who had been treated with warfarin. Our work suggests that larger studies are needed to provide additional specific guidance for patients with diabetes when they are administered anticoagulant drugs or drugs for treating other chronic diseases.
1335. Glucagon Resistance at the Level of Amino Acid Turnover in Obese Subjects With Hepatic Steatosis.
作者: Malte P Suppli.;Jonatan I Bagger.;Asger Lund.;Mia Demant.;Gerrit van Hall.;Charlotte Strandberg.;Merete J Kønig.;Kristoffer Rigbolt.;Jill L Langhoff.;Nicolai J Wewer Albrechtsen.;Jens J Holst.;Tina Vilsbøll.;Filip K Knop.
来源: Diabetes. 2020年69卷6期1090-1099页
Glucagon secretion is regulated by circulating glucose, but it has turned out that amino acids also play an important role and that hepatic amino acid metabolism and glucagon are linked in a mutual feedback cycle, the liver-α-cell axis. On the basis of this knowledge, we hypothesized that hepatic steatosis might impair glucagon's action on hepatic amino acid metabolism and lead to hyperaminoacidemia and hyperglucagonemia. We subjected 15 healthy lean and 15 obese steatotic male participants to a pancreatic clamp with somatostatin and evaluated hepatic glucose and amino acid metabolism when glucagon was at basal levels and at high physiological levels. The degree of steatosis was evaluated from liver biopsy specimens. Total RNA sequencing of liver biopsy specimens from the obese steatotic individuals revealed perturbations in the expression of genes predominantly involved in amino acid metabolism. This group was characterized by fasting hyperglucagonemia, hyperaminoacidemia, and no lowering of amino acid levels in response to high levels of glucagon. Endogenous glucose production was similar between lean and obese individuals. Our results suggest that hepatic steatosis causes resistance to the effect of glucagon on amino acid metabolism. This results in increased amino acid concentrations and increased glucagon secretion, providing a likely explanation for fatty liver-associated hyperglucagonemia.
1336. Liver ChREBP Protects Against Fructose-Induced Glycogenic Hepatotoxicity by Regulating L-Type Pyruvate Kinase.
作者: Jian-Hui Shi.;Jun-Yu Lu.;Heng-Yu Chen.;Chun-Chun Wei.;Xiongfei Xu.;Hao Li.;Qiufang Bai.;Fang-Zhen Xia.;Sin Man Lam.;Hai Zhang.;Ya-Nan Shi.;Dongmei Cao.;Liming Chen.;Guanghou Shui.;Xia Yang.;Yingli Lu.;Yu-Xia Chen.;Weiping J Zhang.
来源: Diabetes. 2020年69卷4期591-602页
Excessive fructose consumption is closely linked to the pathogenesis of metabolic disease. Carbohydrate response element-binding protein (ChREBP) is a transcription factor essential for fructose tolerance in mice. However, the functional significance of liver ChREBP in fructose metabolism remains unclear. Here, we show that liver ChREBP protects mice against fructose-induced hepatotoxicity by regulating liver glycogen metabolism and ATP homeostasis. Liver-specific ablation of ChREBP did not compromise fructose tolerance, but rather caused severe transaminitis and hepatomegaly with massive glycogen overload in mice fed a high-fructose diet, while no obvious inflammation, cell death, or fibrosis was detected in the liver. In addition, liver ATP contents were significantly decreased by ChREBP deficiency in the fed state, which was rendered more pronounced by fructose feeding. Mechanistically, liver contents of glucose-6-phosphate (G6P), an allosteric activator of glycogen synthase, were markedly increased in the absence of liver ChREBP, while fasting-induced glycogen breakdown was not compromised. Furthermore, hepatic overexpression of LPK, a ChREBP target gene in glycolysis, could effectively rescue glycogen overload and ATP reduction, as well as mitigate fructose-induced hepatotoxicity in ChREBP-deficient mice. Taken together, our findings establish a critical role of liver ChREBP in coping with hepatic fructose stress and protecting from hepatotoxicity by regulating LPK.
1337. PPARA Polymorphism Influences the Cardiovascular Benefit of Fenofibrate in Type 2 Diabetes: Findings From ACCORD-Lipid.
作者: Mario Luca Morieri.;Hetal S Shah.;Jennifer Sjaarda.;Petra A Lenzini.;Hannah Campbell.;Alison A Motsinger-Reif.;He Gao.;Laura Lovato.;Sabrina Prudente.;Assunta Pandolfi.;Marcus G Pezzolesi.;Ronald J Sigal.;Guillaume Paré.;Santica M Marcovina.;Daniel M Rotroff.;Elisabetta Patorno.;Luana Mercuri.;Vincenzo Trischitta.;Emily Y Chew.;Peter Kraft.;John B Buse.;Michael J Wagner.;Sharon Cresci.;Hertzel C Gerstein.;Henry N Ginsberg.;Josyf C Mychaleckyj.;Alessandro Doria.
来源: Diabetes. 2020年69卷4期771-783页
The cardiovascular benefits of fibrates have been shown to be heterogeneous and to depend on the presence of atherogenic dyslipidemia. We investigated whether genetic variability in the PPARA gene, coding for the pharmacological target of fibrates (PPAR-α), could be used to improve the selection of patients with type 2 diabetes who may derive cardiovascular benefit from addition of this treatment to statins. We identified a common variant at the PPARA locus (rs6008845, C/T) displaying a study-wide significant influence on the effect of fenofibrate on major cardiovascular events (MACE) among 3,065 self-reported white subjects treated with simvastatin and randomized to fenofibrate or placebo in the ACCORD-Lipid trial. T/T homozygotes (36% of participants) experienced a 51% MACE reduction in response to fenofibrate (hazard ratio 0.49; 95% CI 0.34-0.72), whereas no benefit was observed for other genotypes (Pinteraction = 3.7 × 10-4). The rs6008845-by-fenofibrate interaction on MACE was replicated in African Americans from ACCORD (N = 585, P = 0.02) and in external cohorts (ACCORD-BP, ORIGIN, and TRIUMPH, total N = 3059, P = 0.005). Remarkably, rs6008845 T/T homozygotes experienced a cardiovascular benefit from fibrate even in the absence of atherogenic dyslipidemia. Among these individuals, but not among carriers of other genotypes, fenofibrate treatment was associated with lower circulating levels of CCL11-a proinflammatory and atherogenic chemokine also known as eotaxin (P for rs6008845-by-fenofibrate interaction = 0.003). The GTEx data set revealed regulatory functions of rs6008845 on PPARA expression in many tissues. In summary, we have found a common PPARA regulatory variant that influences the cardiovascular effects of fenofibrate and that could be used to identify patients with type 2 diabetes who would derive benefit from fenofibrate treatment, in addition to those with atherogenic dyslipidemia.
1338. Major Improvement in Wound Healing Through Pharmacologic Mobilization of Stem Cells in Severely Diabetic Rats.
作者: Le Qi.;Ali Reza Ahmadi.;Jinny Huang.;Melissa Chen.;Baohan Pan.;Hiroshi Kuwabara.;Kenichi Iwasaki.;Wei Wang.;Russell Wesson.;Andrew M Cameron.;Shusen Cui.;James Burdick.;Zhaoli Sun.
来源: Diabetes. 2020年69卷4期699-712页
Current therapeutic strategies for diabetic foot ulcer (DFU) have focused on developing topical healing agents, but few agents have controlled prospective data to support their effectiveness in promoting wound healing. We tested a stem cell mobilizing therapy for DFU using a combination of AMD3100 and low-dose FK506 (tacrolimus) (AF) in streptozocin-induced type 1 diabetic (T1DM) rats and type 2 diabetic Goto-Kakizaki (GK) rats that had developed peripheral artery disease and neuropathy. Here, we show that the time for healing back wounds in T1DM rats was reduced from 27 to 19 days, and the foot wound healing time was reduced from 25 to 20 days by treatment with AF (subcutaneously, every other day). Similarly, in GK rats treated with AF, the healing time on back wounds was reduced from 26 to 21 days. Further, this shortened healing time was accompanied by reduced scar and by regeneration of hair follicles. We found that AF therapy mobilized and recruited bone marrow-derived CD133+ and CD34+ endothelial progenitor cells and Ym1/2+ M2 macrophages into the wound sites, associated with enhanced capillary and hair follicle neogenesis. Moreover, AF therapy improved microcirculation in diabetic and neuropathic feet in GK rats. This study provides a novel systemic therapy for healing DFU.
1339. Troponin T Parallels Structural Nerve Damage in Type 2 Diabetes: A Cross-sectional Study Using Magnetic Resonance Neurography.
作者: Johann M E Jende.;Jan B Groener.;Zoltan Kender.;Artur Hahn.;Jakob Morgenstern.;Sabine Heiland.;Peter P Nawroth.;Martin Bendszus.;Stefan Kopf.;Felix T Kurz.
来源: Diabetes. 2020年69卷4期713-723页
Clinical studies have suggested that changes in peripheral nerve microcirculation may contribute to nerve damage in diabetic polyneuropathy (DN). High-sensitivity troponin T (hsTNT) assays have been recently shown to provide predictive values for both cardiac and peripheral microangiopathy in type 2 diabetes (T2D). This study investigated the association of sciatic nerve structural damage in 3 Tesla (3T) magnetic resonance neurography (MRN) with hsTNT and N-terminal pro-brain natriuretic peptide serum levels in patients with T2D. MRN at 3T was performed in 51 patients with T2D (23 without DN, 28 with DN) and 10 control subjects without diabetes. The sciatic nerve's fractional anisotropy (FA), a marker of structural nerve integrity, was correlated with clinical, electrophysiological, and serological data. In patients with T2D, hsTNT showed a negative correlation with the sciatic nerve's FA (r = -0.52, P < 0.001), with a closer correlation in DN patients (r = -0.66, P < 0.001). hsTNT further correlated positively with the neuropathy disability score (r = 0.39, P = 0.005). Negative correlations were found with sural nerve conduction velocities (NCVs) (r = -0.65, P < 0.001) and tibial NCVs (r = -0.44, P = 0.002) and amplitudes (r = -0.53, P < 0.001). This study is the first to show that hsTNT is a potential indicator for structural nerve damage in T2D. Our results indirectly support the hypothesis that microangiopathy contributes to structural nerve damage in T2D.
1340. Pancreas Pathology of Latent Autoimmune Diabetes in Adults (LADA) in Patients and in a LADA Rat Model Compared With Type 1 Diabetes.
Approximately 10% of patients with type 2 diabetes suffer from latent autoimmune diabetes in adults (LADA). This study provides a systematic assessment of the pathology of the endocrine pancreas of patients with LADA and for comparison in a first rat model mimicking the characteristics of patients with LADA. Islets in human and rat pancreases were analyzed by immunohistochemistry for immune cell infiltrate composition, by in situ RT-PCR and quantitative real-time PCR of laser microdissected islets for gene expression of proinflammatory cytokines, the proliferation marker proliferating cell nuclear antigen (PCNA), the anti-inflammatory cytokine interleukin (IL) 10, and the apoptosis markers caspase 3 and TUNEL as well as insulin. Human and rat LADA pancreases showed differences in areas of the pancreas with respect to immune cell infiltration and a changed ratio between the number of macrophages and CD8 T cells toward macrophages in the islet infiltrate. Gene expression analyses revealed a changed ratio due to an increase of IL-1β and a decrease of tumor necrosis factor-α. IL-10, PCNA, and insulin expression were increased in the LADA situation, whereas caspase 3 gene expression was reduced. The analyses into the underlying pathology in human as well as rat LADA pancreases provided identical results, allowing the conclusion that LADA is a milder form of autoimmune diabetes in patients of an advanced age.
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