Other search tools

About this data

The publication data currently available has been vetted by Vanderbilt faculty, staff, administrators and trainees. The data itself is retrieved directly from NCBI's PubMed and is automatically updated on a weekly basis to ensure accuracy and completeness.

If you have any questions or comments, please contact us.

Results: 1 to 10 of 1223

Publication Record

Connections

Pancreas Volume Declines During the First Year After Diagnosis of Type 1 Diabetes and Exhibits Altered Diffusion at Disease Onset.
Virostko J, Williams J, Hilmes M, Bowman C, Wright JJ, Du L, Kang H, Russell WE, Powers AC, Moore DJ
(2019) Diabetes Care 42: 248-257
MeSH Terms: Adolescent, Adult, Atrophy, Autoantibodies, Case-Control Studies, Child, Child, Preschool, Cohort Studies, Diabetes Mellitus, Type 1, Female, Glucose Tolerance Test, Humans, Magnetic Resonance Imaging, Male, Middle Aged, Organ Size, Pancreas, Time Factors, Young Adult
Show Abstract · Added December 18, 2018
OBJECTIVE - This study investigated the temporal dynamics of pancreas volume and microstructure in children and adolescents with recent-onset type 1 diabetes (T1D) and individuals without diabetes, including a subset expressing autoantibodies associated with the early stages of T1D.
RESEARCH DESIGN AND METHODS - MRI was performed in individuals with recent-onset stage 3 T1D ( = 51; median age 13 years) within 100 days after diagnosis (mean 67 days), 6 months, and 1 year postdiagnosis. Longitudinal MRI measurements were also made in similarly aged control participants ( = 57) and in autoantibody-positive individuals without diabetes ( = 20). The MRI protocol consisted of anatomical imaging to determine pancreas volume and quantitative MRI protocols interrogating tissue microstructure and composition.
RESULTS - Within 100 days of diabetes onset, individuals with T1D had a smaller pancreas (median volume 28.6 mL) than control participants (median volume 48.4 mL; < 0.001), including when normalized by individual weight ( < 0.001). Longitudinal measurements of pancreas volume increased in control participants over the year, consistent with adolescent growth, but pancreas volume declined over the first year after T1D diagnosis ( < 0.001). In multiple autoantibody-positive individuals, the pancreas volume was significantly larger than that of the T1D cohort ( = 0.017) but smaller than that of the control cohort ( = 0.04). Diffusion-weighted MRI showed that individuals with recent-onset T1D had a higher apparent diffusion coefficient ( = 0.012), suggesting a loss of cellular structural integrity, with heterogeneous pancreatic distribution.
CONCLUSIONS - These results indicate that pancreas volume is decreased in stages 1, 2, and 3 of T1D and decreases during the first year after diabetes onset and that this loss of pancreatic volume is accompanied by microstructural changes.
© 2018 by the American Diabetes Association.
1 Communities
3 Members
0 Resources
19 MeSH Terms
Ventral striatal dopamine transporter availability is associated with lower trait motor impulsivity in healthy adults.
Smith CT, San Juan MD, Dang LC, Katz DT, Perkins SF, Burgess LL, Cowan RL, Manning HC, Nickels ML, Claassen DO, Samanez-Larkin GR, Zald DH
(2018) Transl Psychiatry 8: 269
MeSH Terms: Adult, Aged, Dopamine Plasma Membrane Transport Proteins, Exploratory Behavior, Female, Fluorodeoxyglucose F18, Humans, Impulsive Behavior, Male, Middle Aged, Personality, Personality Inventory, Positron-Emission Tomography, Ventral Striatum, Young Adult
Show Abstract · Added April 15, 2019
Impulsivity is a transdiagnostic feature of a range of externalizing psychiatric disorders. Preclinical work links reduced ventral striatal dopamine transporter (DAT) availability with heightened impulsivity and novelty seeking. However, there is a lack of human data investigating the relationship between DAT availability, particularly in subregions of the striatum, and the personality traits of impulsivity and novelty seeking. Here we collected PET measures of DAT availability (BP) using the tracer F-FE-PE2I in 47 healthy adult subjects and examined relations between BP in striatum, including its subregions: caudate, putamen, and ventral striatum (VS), and trait impulsivity (Barratt Impulsiveness Scale: BIS-11) and novelty seeking (Tridimensional Personality Questionnaire: TPQ-NS), controlling for age and sex. DAT BP in each striatal subregion showed nominal negative associations with total BIS-11 but not TPQ-NS. At the subscale level, VS DAT BP was significantly associated with BIS-11 motor impulsivity (e.g., taking actions without thinking) after correction for multiple comparisons. VS DAT BP explained 13.2% of the variance in motor impulsivity. Our data demonstrate that DAT availability in VS is negatively related to impulsivity and suggest a particular influence of DAT regulation of dopamine signaling in VS on acting without deliberation (BIS motor impulsivity). While needing replication, these data converge with models of ventral striatal functions that emphasize its role as a key interface linking motivation to action.
0 Communities
1 Members
0 Resources
15 MeSH Terms
Role of Bile Acids and GLP-1 in Mediating the Metabolic Improvements of Bariatric Surgery.
Albaugh VL, Banan B, Antoun J, Xiong Y, Guo Y, Ping J, Alikhan M, Clements BA, Abumrad NN, Flynn CR
(2019) Gastroenterology 156: 1041-1051.e4
MeSH Terms: Anastomosis, Surgical, Animals, Anticholesteremic Agents, Bariatric Surgery, Bile Acids and Salts, Blood Glucose, Cholestyramine Resin, Diet, High-Fat, Gallbladder, Glucagon-Like Peptide 1, Glucagon-Like Peptide-1 Receptor, Glucose Tolerance Test, Ileum, Insulin Resistance, Intestines, Lymph, Male, Mice, Mice, Inbred C57BL, Mice, Knockout, Receptors, Cytoplasmic and Nuclear, Receptors, G-Protein-Coupled, Signal Transduction, Verrucomicrobia, Weight Loss
Show Abstract · Added January 4, 2019
BACKGROUND & AIMS - Bile diversion to the ileum (GB-IL) has strikingly similar metabolic and satiating effects to Roux-en-Y gastric bypass (RYGB) in rodent obesity models. The metabolic benefits of these procedures are thought to be mediated by increased bile acids, although parallel changes in body weight and other confounding variables limit this interpretation.
METHODS - Global G protein-coupled bile acid receptor-1 null (Tgr5) and intestinal-specific farnesoid X receptor null (Fxr) mice on high-fat diet as well as wild-type C57BL/6 and glucagon-like polypeptide 1 receptor deficient (Glp-1r) mice on chow diet were characterized following GB-IL.
RESULTS - GB-IL induced weight loss and improved oral glucose tolerance in Tgr5, but not Fxr mice fed a high-fat diet, suggesting a role for intestinal Fxr. GB-IL in wild-type, chow-fed mice prompted weight-independent improvements in glycemia and glucose tolerance secondary to augmented insulin responsiveness. Improvements were concomitant with increased levels of lymphatic GLP-1 in the fasted state and increased levels of intestinal Akkermansia muciniphila. Improvements in fasting glycemia after GB-IL were mitigated with exendin-9, a GLP-1 receptor antagonist, or cholestyramine, a bile acid sequestrant. The glucoregulatory effects of GB-IL were lost in whole-body Glp-1r mice.
CONCLUSIONS - Bile diversion to the ileum improves glucose homeostasis via an intestinal Fxr-Glp-1 axis. Altered intestinal bile acid availability, independent of weight loss, and intestinal Akkermansia muciniphila appear to mediate the metabolic changes observed after bariatric surgery and might be manipulated for treatment of obesity and diabetes.
Copyright © 2019 AGA Institute. Published by Elsevier Inc. All rights reserved.
0 Communities
2 Members
0 Resources
25 MeSH Terms
Large-scale whole-exome sequencing association studies identify rare functional variants influencing serum urate levels.
Tin A, Li Y, Brody JA, Nutile T, Chu AY, Huffman JE, Yang Q, Chen MH, Robinson-Cohen C, Macé A, Liu J, Demirkan A, Sorice R, Sedaghat S, Swen M, Yu B, Ghasemi S, Teumer A, Vollenweider P, Ciullo M, Li M, Uitterlinden AG, Kraaij R, Amin N, van Rooij J, Kutalik Z, Dehghan A, McKnight B, van Duijn CM, Morrison A, Psaty BM, Boerwinkle E, Fox CS, Woodward OM, Köttgen A
(2018) Nat Commun 9: 4228
MeSH Terms: Exome, Genetic Predisposition to Disease, Glucose Transport Proteins, Facilitative, Humans, Kidney Function Tests, Meta-Analysis as Topic, Organic Anion Transporters, Organic Cation Transport Proteins, Protein Structure, Secondary, Uric Acid
Show Abstract · Added January 3, 2019
Elevated serum urate levels can cause gout, an excruciating disease with suboptimal treatment. Previous GWAS identified common variants with modest effects on serum urate. Here we report large-scale whole-exome sequencing association studies of serum urate and kidney function among ≤19,517 European ancestry and African-American individuals. We identify aggregate associations of low-frequency damaging variants in the urate transporters SLC22A12 (URAT1; p = 1.3 × 10) and SLC2A9 (p = 4.5 × 10). Gout risk in rare SLC22A12 variant carriers is halved (OR = 0.5, p = 4.9 × 10). Selected rare variants in SLC22A12 are validated in transport studies, confirming three as loss-of-function (R325W, R405C, and T467M) and illustrating the therapeutic potential of the new URAT1-blocker lesinurad. In SLC2A9, mapping of rare variants of large effects onto the predicted protein structure reveals new residues that may affect urate binding. These findings provide new insights into the genetic architecture of serum urate, and highlight molecular targets in SLC22A12 and SLC2A9 for lowering serum urate and preventing gout.
0 Communities
1 Members
0 Resources
MeSH Terms
CRISPR/Cas9 engineering of a KIM-1 reporter human proximal tubule cell line.
Veach RA, Wilson MH
(2018) PLoS One 13: e0204487
MeSH Terms: Acute Kidney Injury, CRISPR-Cas Systems, Cell Line, Cisplatin, Gene Knock-In Techniques, Gene Targeting, Genes, Reporter, Genetic Engineering, Glucose, Green Fluorescent Proteins, Hepatitis A Virus Cellular Receptor 1, Homologous Recombination, Humans, Kidney Tubules, Proximal, Luciferases, Up-Regulation
Show Abstract · Added December 13, 2018
We used the CRISPR/Cas9 system to knock-in reporter transgenes at the kidney injury molecule-1 (KIM-1) locus and isolated human proximal tubule cell (HK-2) clones. PCR verified targeted knock-in of the luciferase and eGFP reporter at the KIM-1 locus. HK-2-KIM-1 reporter cells responded to various stimuli including hypoxia, cisplatin, and high glucose, indicative of upregulation of KIM-1 expression. We attempted using CRISPR/Cas9 to also engineer the KIM-1 reporter in telomerase-immortalized human RPTEC cells. However, these cells demonstrated an inability to undergo homologous recombination at the target locus. KIM-1-reporter human proximal tubular cells could be valuable tools in drug discovery for molecules inhibiting kidney injury. Additionally, our gene targeting strategy could be used in other cell lines to evaluate the biology of KIM-1 in vitro or in vivo.
0 Communities
1 Members
0 Resources
16 MeSH Terms
High CD8 T-Cell Receptor Clonality and Altered CDR3 Properties Are Associated With Elevated Isolevuglandins in Adipose Tissue During Diet-Induced Obesity.
McDonnell WJ, Koethe JR, Mallal SA, Pilkinton MA, Kirabo A, Ameka MK, Cottam MA, Hasty AH, Kennedy AJ
(2018) Diabetes 67: 2361-2376
MeSH Terms: Adipose Tissue, Animals, CD8-Positive T-Lymphocytes, Complementarity Determining Regions, Diet, High-Fat, Glucose Tolerance Test, Insulin Resistance, Liver, Male, Mice, Obesity, Prostaglandins
Show Abstract · Added March 26, 2019
Adipose tissue (AT) CD4 and CD8 T cells contribute to obesity-associated insulin resistance. Prior studies identified conserved T-cell receptor (TCR) chain families in obese AT, but the presence and clonal expansion of specific TCR sequences in obesity has not been assessed. We characterized AT and liver CD8 and CD4 TCR repertoires of mice fed a low-fat diet (LFD) and high-fat diet (HFD) using deep sequencing of the TCRβ chain to quantify clonal expansion, gene usage, and CDR3 sequence. In AT CD8 T cells, HFD reduced TCR diversity, increased the prevalence of public TCR clonotypes, and selected for TCR CDR3 regions enriched in positively charged and less polarized amino acids. Although TCR repertoire alone could distinguish between LFD- and HFD-fed mice, these properties of the CDR3 region of AT CD8 T cells from HFD-fed mice led us to examine the role of negatively charged and nonpolar isolevuglandin (isoLG) adduct-containing antigen-presenting cells within AT. IsoLG-adducted protein species were significantly higher in AT macrophages of HFD-fed mice; isoLGs were elevated in M2-polarized macrophages, promoting CD8 T-cell activation. Our findings demonstrate that clonal TCR expansion that favors positively charged CDR3s accompanies HFD-induced obesity, which may be an antigen-driven response to isoLG accumulation in macrophages.
© 2018 by the American Diabetes Association.
0 Communities
1 Members
0 Resources
MeSH Terms
Metformin reduces liver glucose production by inhibition of fructose-1-6-bisphosphatase.
Hunter RW, Hughey CC, Lantier L, Sundelin EI, Peggie M, Zeqiraj E, Sicheri F, Jessen N, Wasserman DH, Sakamoto K
(2018) Nat Med 24: 1395-1406
MeSH Terms: Adenosine Monophosphate, Aminoimidazole Carboxamide, Animals, Base Sequence, Chickens, Disease Models, Animal, Fructose-Bisphosphatase, Glucose, Glucose Intolerance, Homeostasis, Humans, Hypoglycemia, Liver, Metformin, Mice, Inbred C57BL, Mutation, Obesity, Prodrugs, Ribonucleotides
Show Abstract · Added March 26, 2019
Metformin is a first-line drug for the treatment of individuals with type 2 diabetes, yet its precise mechanism of action remains unclear. Metformin exerts its antihyperglycemic action primarily through lowering hepatic glucose production (HGP). This suppression is thought to be mediated through inhibition of mitochondrial respiratory complex I, and thus elevation of 5'-adenosine monophosphate (AMP) levels and the activation of AMP-activated protein kinase (AMPK), though this proposition has been challenged given results in mice lacking hepatic AMPK. Here we report that the AMP-inhibited enzyme fructose-1,6-bisphosphatase-1 (FBP1), a rate-controlling enzyme in gluconeogenesis, functions as a major contributor to the therapeutic action of metformin. We identified a point mutation in FBP1 that renders it insensitive to AMP while sparing regulation by fructose-2,6-bisphosphate (F-2,6-P), and knock-in (KI) of this mutant in mice significantly reduces their response to metformin treatment. We observe this during a metformin tolerance test and in a metformin-euglycemic clamp that we have developed. The antihyperglycemic effect of metformin in high-fat diet-fed diabetic FBP1-KI mice was also significantly blunted compared to wild-type controls. Collectively, we show a new mechanism of action for metformin and provide further evidence that molecular targeting of FBP1 can have antihyperglycemic effects.
1 Communities
1 Members
0 Resources
19 MeSH Terms
Loss of MYO5B Leads to Reductions in Na Absorption With Maintenance of CFTR-Dependent Cl Secretion in Enterocytes.
Engevik AC, Kaji I, Engevik MA, Meyer AR, Weis VG, Goldstein A, Hess MW, Müller T, Koepsell H, Dudeja PK, Tyska M, Huber LA, Shub MD, Ameen N, Goldenring JR
(2018) Gastroenterology 155: 1883-1897.e10
MeSH Terms: Animals, Aquaporins, Chlorides, Cystic Fibrosis Transmembrane Conductance Regulator, Duodenum, Enterocytes, Gene Silencing, Humans, Intestinal Mucosa, Intestines, Malabsorption Syndromes, Mice, Mice, Knockout, Microvilli, Mucolipidoses, Myosin Type V, Protein Transport, Sodium-Glucose Transporter 1, Sodium-Hydrogen Exchanger 3, Sodium-Hydrogen Exchangers, Sucrase-Isomaltase Complex, Tamoxifen
Show Abstract · Added February 7, 2019
BACKGROUND & AIMS - Inactivating mutations in MYO5B cause microvillus inclusion disease (MVID), but the physiological cause of the diarrhea associated with this disease is unclear. We investigated whether loss of MYO5B results in aberrant expression of apical enterocyte transporters.
METHODS - We studied alterations in apical membrane transporters in MYO5B-knockout mice, as well as mice with tamoxifen-inducible, intestine-specific disruption of Myo5b (VilCre;Myo5b mice) or those not given tamoxifen (controls). Intestinal tissues were collected from mice and analyzed by immunostaining, immunoelectron microscopy, or cultured enteroids were derived. Functions of brush border transporters in intestinal mucosa were measured in Ussing chambers. We obtained duodenal biopsy specimens from individuals with MVID and individuals without MVID (controls) and compared transporter distribution by immunocytochemistry.
RESULTS - Compared to intestinal tissues from littermate controls, intestinal tissues from MYO5B-knockout mice had decreased apical localization of SLC9A3 (also called NHE3), SLC5A1 (also called SGLT1), aquaporin (AQP) 7, and sucrase isomaltase, and subapical localization of intestinal alkaline phosphatase and CDC42. However, CFTR was present on apical membranes of enterocytes from MYO5B knockout and control mice. Intestinal biopsies from patients with MVID had subapical localization of NHE3, SGLT1, and AQP7, but maintained apical CFTR. After tamoxifen administration, VilCre;Myo5b mice lost apical NHE3, SGLT1, DRA, and AQP7, similar to germline MYO5B knockout mice. Intestinal tissues from VilCre;Myo5b mice had increased CFTR in crypts and CFTR localized to the apical membranes of enterocytes. Intestinal mucosa from VilCre;Myo5b mice given tamoxifen did not have an intestinal barrier defect, based on Ussing chamber analysis, but did have decreased SGLT1 activity and increased CFTR activity.
CONCLUSIONS - Although trafficking of many apical transporters is regulated by MYO5B, trafficking of CFTR is largely independent of MYO5B. Decreased apical localization of NHE3, SGLT1, DRA, and AQP7 might be responsible for dysfunctional water absorption in enterocytes of patients with MVID. Maintenance of apical CFTR might exacerbate water loss by active secretion of chloride into the intestinal lumen.
Copyright © 2018 AGA Institute. Published by Elsevier Inc. All rights reserved.
1 Communities
0 Members
0 Resources
MeSH Terms
Increases in bioactive lipids accompany early metabolic changes associated with β-cell expansion in response to short-term high-fat diet.
Seferovic MD, Beamish CA, Mosser RE, Townsend SE, Pappan K, Poitout V, Aagaard KM, Gannon M
(2018) Am J Physiol Endocrinol Metab 315: E1251-E1263
MeSH Terms: Animals, Blood Glucose, Cell Proliferation, Diabetes Mellitus, Type 2, Diet, High-Fat, Insulin Resistance, Insulin-Secreting Cells, Lipid Metabolism, Lipids, Liver, Male, Mice, Muscle, Skeletal, Obesity
Show Abstract · Added April 15, 2019
Pancreatic β-cell expansion is a highly regulated metabolic adaptation to increased somatic demands, including obesity and pregnancy; adult β cells otherwise rarely proliferate. We previously showed that high-fat diet (HFD) feeding induces mouse β-cell proliferation in less than 1 wk in the absence of insulin resistance. Here we metabolically profiled tissues from a short-term HFD β-cell expansion mouse model to identify pathways and metabolite changes associated with β-cell proliferation. Mice fed HFD vs. chow diet (CD) showed a 14.3% increase in body weight after 7 days; β-cell proliferation increased 1.75-fold without insulin resistance. Plasma from 1-wk HFD-fed mice induced β-cell proliferation ex vivo. The plasma, as well as liver, skeletal muscle, and bone, were assessed by LC and GC mass-spectrometry for global metabolite changes. Of the 1,283 metabolites detected, 159 showed significant changes [false discovery rate (FDR) < 0.1]. The majority of changes were in liver and muscle. Pathway enrichment analysis revealed key metabolic changes in steroid synthesis and lipid metabolism, including free fatty acids and other bioactive lipids. Other important enrichments included changes in the citric acid cycle and 1-carbon metabolism pathways implicated in DNA methylation. Although the minority of changes were observed in bone and plasma (<20), increased p-cresol sulfate was increased >4 fold in plasma (the largest increase in all tissues), and pantothenate (vitamin B) decreased >2-fold. The results suggest that HFD-mediated β-cell expansion is associated with complex, global metabolite changes. The finding could be a significant insight into Type 2 diabetes pathogenesis and potential novel drug targets.
0 Communities
1 Members
0 Resources
14 MeSH Terms
Enterically delivered insulin tregopil exhibits rapid absorption characteristics and a pharmacodynamic effect similar to human insulin in conscious dogs.
Gregory JM, Lautz M, Moore LM, Williams PE, Reddy P, Cherrington AD
(2019) Diabetes Obes Metab 21: 160-169
MeSH Terms: Animals, Blood Glucose, Diabetes Mellitus, Dogs, Female, Glucose, Humans, Insulin, Insulin, Regular, Human, Male
Show Abstract · Added November 17, 2018
AIMS - Current therapy fails to emulate rapid (first-phase) insulin release in relation to a meal, a key defect in types 1 and 2 diabetes. We aimed to quantify the pharmacokinetic (PK) and pharmacodynamic (PD) profile of insulin tregopil, an enterically-absorbed insulin analog that restores the normal distribution of insulin between the hepatic portal and peripheral circulations.
MATERIALS AND METHODS - The PK and PD profiles of insulin tregopil were studied in overnight-fasted, catheterized, conscious canines using four approaches: (1) equimolar intraportal infusions of tregopil vs human insulin; (2) escalating doses of oral tregopil; (3) identical, consecutive enteric doses of tregopil; and (4) comparison of oral tregopil to inhaled and subcutaneous human insulin administration.
RESULTS - Equimolar intraportal infusions of tregopil and human insulin resulted in very similar PK profiles and PD profiles were nearly identical. Enteric delivery of tregopil brought about rapid absorption with t = 20 minutes in most cases. Median t was 20 minutes for oral tregopil and inhaled insulin and 88 minutes for subcutaneous human insulin. The time required for arterial plasma insulin levels to return to baseline was approximately 90, 210 and 360 minutes for oral tregopil, inhaled insulin and subcutaneous insulin, respectively.
CONCLUSIONS - Enterically delivered tregopil is rapidly absorbed and restores a portal-to-peripheral vascular distribution. These characteristics should improve postprandial hyperglycaemia in types 1 and 2 diabetes.
© 2018 John Wiley & Sons Ltd.
0 Communities
1 Members
0 Resources
10 MeSH Terms