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Adams JD, Egan AM, Laurenti MC, Schembri Wismayer D, Bailey KR, Cobelli C, Dalla Man C, Vella A. The Effect of Diabetes-Associated Variation in TCF7L2 on Postprandial Glucose Metabolism When Glucagon and Insulin Concentrations Are Matched. Metab Syndr Relat Disord 2022; 20:329-335. [PMID: 35442800 PMCID: PMC9419949 DOI: 10.1089/met.2021.0136] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Background: The rs7903146 variant in the TCF7L2 gene is associated with defects in postprandial insulin and glucagon secretion and increased risk of type 2 diabetes. However, it is unclear if this variant has effects on glucose metabolism that are independent of islet function. Methods: We studied 54 nondiabetic subjects on two occasions where endogenous hormone secretion was inhibited by somatostatin. Twenty-nine subjects were homozygous for the diabetes-associated allele (TT) and 25 for the diabetes-protective allele (CC) at rs7903146, but otherwise matched for anthropometric characteristics. On 1 day, glucagon infused at a rate of 0.65 ng/kg/min, and at 0 min prevented a fall in glucagon (nonsuppressed day). On the contrary, infusion commenced at 120 min to create a transient fall in glucagon (suppressed day). Subjects received glucose (labeled with [3-3H]-glucose) infused to mimic the systemic appearance of oral glucose. Insulin was infused to mimic a prandial insulin response. Endogenous glucose production (EGP) was measured using the tracer dilution technique. Results: Lack of glucagon suppression increased postchallenge glucose concentrations and impaired EGP suppression. However, in the presence of matched insulin and glucagon concentrations, genetic variation in TCF7L2 did not alter glucose metabolism. Conclusion: These data suggest that genetic variation in TCF7L2 alters glucose metabolism through changes in islet hormone secretion.
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Affiliation(s)
- Jon D Adams
- Division of Endocrinology, Diabetes and Metabolism, Mayo Clinic College of Medicine, Rochester, Minnesota, USA
| | - Aoife M Egan
- Division of Endocrinology, Diabetes and Metabolism, Mayo Clinic College of Medicine, Rochester, Minnesota, USA
| | - Marcello C Laurenti
- Division of Endocrinology, Diabetes and Metabolism, Mayo Clinic College of Medicine, Rochester, Minnesota, USA
| | - Daniel Schembri Wismayer
- Division of Endocrinology, Diabetes and Metabolism, Mayo Clinic College of Medicine, Rochester, Minnesota, USA
| | - Kent R Bailey
- Division of Biomedical Statistics and Informatics, Mayo Clinic, Rochester, Minnesota, USA
| | - Claudio Cobelli
- Department of Woman and Child's Health and University of Padova, Padova, Italy
| | - Chiara Dalla Man
- Department of Information Engineering, University of Padova, Padova, Italy
| | - Adrian Vella
- Division of Endocrinology, Diabetes and Metabolism, Mayo Clinic College of Medicine, Rochester, Minnesota, USA
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Egan AM, Laurenti MC, Hurtado Andrade MD, Dalla Man C, Cobelli C, Bailey KR, Vella A. Limitations of the fasting proinsulin to insulin ratio as a measure of β-cell health in people with and without impaired glucose tolerance. Eur J Clin Invest 2021; 51:e13469. [PMID: 33289929 PMCID: PMC8169515 DOI: 10.1111/eci.13469] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Revised: 12/02/2020] [Accepted: 12/04/2020] [Indexed: 12/19/2022]
Abstract
BACKGROUND The fasting proinsulin to insulin ratio is elevated in people with type 2 diabetes and has been suggested as a marker of β-cell health. However, its utility in discriminating between individuals with varying degrees of β-cell dysfunction is unclear. Proinsulin has a very different half-life to insulin and unlike insulin does not undergo hepatic extraction prior to reaching the systemic circulation. Given these limitations, we sought to examine the relationship between fasting and postprandial concentrations of β-cell polypeptides (proinsulin, insulin and C-peptide) in people with normal and impaired glucose tolerance in differing metabolic environments. DESIGN Subjects were studied on two occasions in random order while undergoing an oral challenge. During one study day, free fatty acids were elevated (to induce insulin resistance) by infusion of Intralipid with heparin. Proinsulin to insulin and proinsulin to C-peptide ratios were calculated for the 0-, 30-, 60- and 240-minute time points. Insulin action (Si) and β-cell responsivity (Φ) indices were calculated using the oral minimal model. RESULTS The fasting proinsulin to c-peptide or fasting proinsulin to insulin ratios did not differ between groups and did not predict subsequent β-cell responsivity to glucose during the glycerol or Intralipid study days in either group. CONCLUSIONS Among nondiabetic individuals, the fasting proinsulin to insulin ratio is not a useful marker of β-cell function.
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Affiliation(s)
- Aoife M Egan
- Division of Endocrinology, Diabetes and Metabolism, Mayo Clinic, Rochester, MN, USA
| | - Marcello C Laurenti
- Division of Endocrinology, Diabetes and Metabolism, Mayo Clinic, Rochester, MN, USA
| | | | - Chiara Dalla Man
- Department of Information Engineering, Università degli Studi di Padova, Padova, Italy
| | - Claudio Cobelli
- Department of Information Engineering, Università degli Studi di Padova, Padova, Italy
| | - Kent R Bailey
- Division of Biomedical Statistics and Informatics, Mayo Clinic, Rochester, MN, USA
| | - Adrian Vella
- Division of Endocrinology, Diabetes and Metabolism, Mayo Clinic, Rochester, MN, USA
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Vincent EE, Yaghootkar H. Using genetics to decipher the link between type 2 diabetes and cancer: shared aetiology or downstream consequence? Diabetologia 2020; 63:1706-1717. [PMID: 32705315 PMCID: PMC7406536 DOI: 10.1007/s00125-020-05228-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Accepted: 05/18/2020] [Indexed: 12/11/2022]
Abstract
Recent developments in the field of genetics have accelerated our understanding of the aetiology of complex diseases. Type 2 diabetes mellitus and cancer are no exception, with large-scale genome-wide association studies (GWAS) facilitating exploration of the underlying pathology. Here, we discuss how genetics studies can be used to investigate the relationship between these complex diseases. Observational epidemiological studies consistently report that people with type 2 diabetes have a higher risk of several types of cancer. Indeed, type 2 diabetes and cancer share many common risk factors, such as obesity, ageing, poor diet and low levels of physical activity. However, questions remain regarding the biological mechanisms that link these two diseases. Large-scale GWAS of type 2 diabetes and cancer allow us to consider the evidence for shared genetic architecture. Several shared susceptibility genes have been identified, yet tissue specificity and direction of effect must be taken into account when considering common genetic aetiology. We also consider how GWAS, and associated techniques such as Mendelian randomisation, allow us to dissect the link between the two diseases and address questions such as 'Does type 2 diabetes cause cancer or is the increased risk observed driven by higher adiposity or another associated metabolic feature?' Graphical abstract.
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Affiliation(s)
- Emma E Vincent
- MRC Integrative Epidemiology Unit at the University of Bristol, Bristol, Bristol, UK.
- Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, UK.
- School of Cellular and Molecular Medicine, Biomedical Science Building, University of Bristol, Bristol, BS8 1TW, UK.
| | - Hanieh Yaghootkar
- Genetics of Complex Traits, University of Exeter Medical School, Royal Devon & Exeter Hospital, Exeter, UK
- School of Life Sciences, College of Liberal Arts and Science, University of Westminster, London, UK
- Division of Medical Sciences, Department of Health Sciences, Luleå University of Technology, Luleå, Sweden
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Hubáček JA, Šedová L, Olišarová V, Adámková V, Tóthová V. Different prevalence of T2DM risk alleles in Roma population in comparison with the majority Czech population. Mol Genet Genomic Med 2020; 8:e1361. [PMID: 32578971 PMCID: PMC7507457 DOI: 10.1002/mgg3.1361] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Revised: 05/11/2020] [Accepted: 05/19/2020] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND The Czech governmental study suggests up to a 25% higher prevalence of type 2 diabetes mellitus (T2DM) in the Roma population than within the majority population. It is not known whether and to what extent these differences have a genetic background. METHODS To analyze whether the frequencies of the alleles/genotypes of the FTO, TCF7L2, CDKN2A/2B, MAEA, TLE4, IGF2BP2, ARAP1, and KCNJ11 genes differ between the two major ethnic groups in the Czech Republic, we examined them in DNA samples from 302 Roma individuals and 298 Czech individuals. RESULTS Compared to the majority population, Roma are more likely to carry risk alleles in the FTO (26% vs. 16% GG homozygotes, p < .01), IGF2BP2 (22% vs. 10% TT homozygotes, p < .0001), ARAP1 (98% vs. 95% of A allele carriers, p < .005), and CDKN2A/2B (81% vs. 66% of TT homozygotes, p < .001) genes; however, less frequently they are carriers of the TCF7L2 risk allele (34% vs. 48% of the T allele p < .0005). Finally, we found significant accumulation of T2DM-associated alleles between the Roma population in comparison with the majority population (25.4% vs. 15.2% of the carriers of at least 12 risk alleles; p < .0001). CONCLUSION The increased prevalence of T2DM in the Roma population may have a background in different frequencies of the risk alleles of genes associated with T2DM development.
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Affiliation(s)
- Jaroslav A. Hubáček
- Centre for Experimental MedicineInstitute for Clinical and Experimental MedicinePragueCzech Republic
| | - Lenka Šedová
- Faculty of Health and Social SciencesUniversity of South BohemiaČeské BudějoviceCzech Republic
| | - Věra Olišarová
- Faculty of Health and Social SciencesUniversity of South BohemiaČeské BudějoviceCzech Republic
| | - Věra Adámková
- Department of Preventive CardiologyInstitute for Clinical and Experimental MedicinePragueCzech Republic
| | - Valérie Tóthová
- Faculty of Health and Social SciencesUniversity of South BohemiaČeské BudějoviceCzech Republic
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Aksit MA, Pace RG, Vecchio-Pagán B, Ling H, Rommens JM, Boelle PY, Guillot L, Raraigh KS, Pugh E, Zhang P, Strug LJ, Drumm ML, Knowles MR, Cutting GR, Corvol H, Blackman SM. Genetic Modifiers of Cystic Fibrosis-Related Diabetes Have Extensive Overlap With Type 2 Diabetes and Related Traits. J Clin Endocrinol Metab 2020; 105:5599821. [PMID: 31697830 PMCID: PMC7236628 DOI: 10.1210/clinem/dgz102] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Accepted: 10/02/2019] [Indexed: 02/08/2023]
Abstract
CONTEXT Individuals with cystic fibrosis (CF) develop a distinct form of diabetes characterized by β-cell dysfunction and islet amyloid accumulation similar to type 2 diabetes (T2D), but generally have normal insulin sensitivity. CF-related diabetes (CFRD) risk is determined by both CFTR, the gene responsible for CF, and other genetic variants. OBJECTIVE To identify genetic modifiers of CFRD and determine the genetic overlap with other types of diabetes. DESIGN AND PATIENTS A genome-wide association study was conducted for CFRD onset on 5740 individuals with CF. Weighted polygenic risk scores (PRSs) for type 1 diabetes (T1D), T2D, and diabetes endophenotypes were tested for association with CFRD. RESULTS Genome-wide significance was obtained for variants at a novel locus (PTMA) and 2 known CFRD genetic modifiers (TCF7L2 and SLC26A9). PTMA and SLC26A9 variants were CF-specific; TCF7L2 variants also associated with T2D. CFRD was strongly associated with PRSs for T2D, insulin secretion, postchallenge glucose concentration, and fasting plasma glucose, and less strongly with T1D PRSs. CFRD was inconsistently associated with PRSs for insulin sensitivity and was not associated with a PRS for islet autoimmunity. A CFRD PRS comprising variants selected from these PRSs (with a false discovery rate < 0.1) and the genome-wide significant variants was associated with CFRD in a replication population. CONCLUSIONS CFRD and T2D have more etiologic and mechanistic overlap than previously known, aligning along pathways involving β-cell function rather than insulin sensitivity. Two CFRD risk loci are unrelated to T2D and may affect multiple aspects of CF. An 18-variant PRS stratifies risk of CFRD in an independent population.
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Affiliation(s)
- Melis A Aksit
- McKusick-Nathans Institute of the Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Rhonda G Pace
- Marsico Lung Institute/UNC CF Research Center, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | | | - Hua Ling
- Center for Inherited Disease Research, Johns Hopkins University, Baltimore, Maryland
| | - Johanna M Rommens
- The Hospital for Sick Children and the University of Toronto, Toronto, Ontario, Canada
| | - Pierre-Yves Boelle
- Sorbonne Université, INSERM, Institut Pierre Louis d’Épidémiologie et de Santé Publique, iPLESP, AP-HP, Hôpital Saint-Antoine, Paris, France
| | - Loic Guillot
- Sorbonne Université, INSERM, Centre de Recherche Saint-Antoine, CRSA, Paris, France
| | - Karen S Raraigh
- McKusick-Nathans Institute of the Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Elizabeth Pugh
- Center for Inherited Disease Research, Johns Hopkins University, Baltimore, Maryland
| | - Peng Zhang
- Center for Inherited Disease Research, Johns Hopkins University, Baltimore, Maryland
| | - Lisa J Strug
- The Hospital for Sick Children and the University of Toronto, Toronto, Ontario, Canada
| | | | - Michael R Knowles
- Marsico Lung Institute/UNC CF Research Center, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Garry R Cutting
- McKusick-Nathans Institute of the Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Harriet Corvol
- Sorbonne Université, INSERM, Centre de Recherche Saint-Antoine, CRSA, Paris, France
| | - Scott M Blackman
- McKusick-Nathans Institute of the Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland
- Division of Pediatric Endocrinology, Johns Hopkins University School of Medicine, Baltimore, Maryland
- Correspondence and Reprint Requests: Scott M. Blackman, McKusick-Nathans Institute of the Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205. E-mail:
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Dujic T, Bego T, Malenica M, Velija-Asimi Z, Ahlqvist E, Groop L, Pearson ER, Causevic A, Semiz S. Effects of TCF7L2 rs7903146 variant on metformin response in patients with type 2 diabetes. Bosn J Basic Med Sci 2019; 19:368-374. [PMID: 31070566 DOI: 10.17305/bjbms.2019.4181] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2019] [Accepted: 04/05/2019] [Indexed: 11/16/2022] Open
Abstract
The response to metformin, the most commonly used drug for the treatment of type 2 diabetes (T2D), is highly variable. The common variant rs7903146 C>T within the transcription factor 7-like 2 gene (TCF7L2) is the strongest genetic risk factor associated with T2D to date. In this study, we explored the effects of the TCF7L2 rs7903146 genotype on metformin response in T2D. The study included 86 newly diagnosed patients with T2D, incident users of metformin. Levels of fasting glucose, insulin, HbA1c, total cholesterol, HDL-cholesterol, LDL-cholesterol, triglycerides, and anthropometric parameters were measured prior to metformin therapy, and 6 and 12 months after the treatment. Genotyping of the TCF7L2 rs7903146 was performed by the Sequenom MassARRAY® iPLEX® platform. At baseline, the diabetes risk allele (T) showed an association with lower triglyceride levels (p = 0.037). After 12 months of metformin treatment, the T allele was associated with 25.9% lower fasting insulin levels (95% CI 10.9-38.3%, p = 0.002) and 29.1% lower HOMA-IR index (95% CI 10.1-44.1%, p = 0.005), after adjustment for baseline values. Moreover, the T allele was associated with 6.7% lower fasting glucose levels (95% CI 1.1-12.0%, p = 0.021), adjusted for baseline glucose and baseline HOMA-%B levels, after 6 months of metformin treatment. This effect was more pronounced in the TT carriers who had 16.8% lower fasting glucose levels (95% CI 7.0-25.6%, p = 0.002) compared to the patients with CC genotype. Our results suggest that the TCF7L2 rs7903146 variant affects markers of insulin resistance and glycemic response to metformin in newly diagnosed patients with T2D within the first year of metformin treatment.
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Affiliation(s)
- Tanja Dujic
- Department of Biochemistry and Clinical Analysis, Faculty of Pharmacy, University of Sarajevo, Sarajevo, Bosnia and Herzegovina.
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Egan A, Vella A. TTP399: an investigational liver-selective glucokinase (GK) activator as a potential treatment for type 2 diabetes. Expert Opin Investig Drugs 2019; 28:741-747. [DOI: 10.1080/13543784.2019.1654993] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Aoife Egan
- Division of Endocrinology and Diabetes, Diabetes and Metabolism Department of Medicine, Rochester, MN, USA
| | - Adrian Vella
- Division of Endocrinology and Diabetes, Diabetes and Metabolism Department of Medicine, Rochester, MN, USA
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