Daniela Kempe-Teufel1,2,3, Fausto Machicao2,4, Jürgen Machann2,3,5, Anja Böhm1,2,3, Fritz Schick2,3,5, Andreas Fritsche1,2,3, Norbert Stefan1,2,3, Martin Hrabě de Angelis2,4,6, Hans-Ulrich Häring1,2,3, Harald Staiger2,3,7. 1. Department of Internal Medicine, Division of Endocrinology, Diabetology, Angiology, Nephrology and Clinical Chemistry, Eberhard Karls University Tübingen, Tübingen, Germany. 2. German Center for Diabetes Research (DZD), Neuherberg, Germany. 3. Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Centre Munich at the University of Tübingen, Tübingen, Germany. 4. Institute of Experimental Genetics, Helmholtz Center Munich, Neuherberg, Germany. 5. Department of Diagnostic and Interventional Radiology, Section on Experimental Radiology, Eberhard Karls University Tübingen, Tübingen, Germany. 6. Chair of Experimental Genetics, Technical University Munich, Neuherberg, Germany. 7. Institute of Pharmaceutical Sciences, Department of Pharmacy and Biochemistry, Eberhard Karls University Tübingen, Tübingen, Germany.
Abstract
CONTEXT: Primary dysregulation of adipose tissue lipolysis caused by genetic variation and independent of insulin resistance could explain unhealthy body fat distribution and its metabolic consequences. OBJECTIVE: To analyze common single nucleotide polymorphisms (SNPs) in 48 lipolysis-, but not insulin-signaling-related genes, to form polygenic risk scores of lipolysis-associated SNPs, and to investigate their effects on body fat distribution, glycemia, insulin sensitivity, insulin secretion, and proinsulin conversion. STUDY DESIGN, PARTICIPANTS, AND METHODS: SNP array, anthropometric, and metabolic data were available from up to 2789 participants without diabetes of the Tübingen Family study of type 2 diabetes characterized by oral glucose tolerance tests. In a subgroup (n = 942), magnetic resonance measurements of body fat stores were available. RESULTS: We identified insulin-sensitivity-independent nominal associations (P < 0.05) of SNPs in 10 genes with plasma free fatty acids (FFAs), in 7 genes with plasma glycerol and in 6 genes with both, plasma FFAs and glycerol. A score formed of the latter SNPs (in ADCY4, CIDEA, GNAS, PDE8B, PRKAA1, PRKAG2) was associated with plasma FFA and glycerol measurements (1.4*10-9 ≤ P ≤ 1.2*10-5), visceral adipose tissue mass (P = 0.0326), and proinsulin conversion (P ≤ 0.0272). The more lipolysis-increasing alleles a subject had, the lower was the visceral fat mass and the lower the proinsulin conversion. CONCLUSIONS: We found evidence for a genetic basis of adipose tissue lipolysis resulting from common SNPs in CIDEA, AMP-activated protein kinase subunits, and cAMP signaling components. A genetic score of lipolysis-increasing alleles determined lower visceral fat mass and lower proinsulin conversion.
CONTEXT: Primary dysregulation of adipose tissue lipolysis caused by genetic variation and independent of insulin resistance could explain unhealthy body fat distribution and its metabolic consequences. OBJECTIVE: To analyze common single nucleotide polymorphisms (SNPs) in 48 lipolysis-, but not insulin-signaling-related genes, to form polygenic risk scores of lipolysis-associated SNPs, and to investigate their effects on body fat distribution, glycemia, insulin sensitivity, insulin secretion, and proinsulin conversion. STUDY DESIGN, PARTICIPANTS, AND METHODS: SNP array, anthropometric, and metabolic data were available from up to 2789 participants without diabetes of the Tübingen Family study of type 2 diabetes characterized by oral glucose tolerance tests. In a subgroup (n = 942), magnetic resonance measurements of body fat stores were available. RESULTS: We identified insulin-sensitivity-independent nominal associations (P < 0.05) of SNPs in 10 genes with plasma free fatty acids (FFAs), in 7 genes with plasma glycerol and in 6 genes with both, plasma FFAs and glycerol. A score formed of the latter SNPs (in ADCY4, CIDEA, GNAS, PDE8B, PRKAA1, PRKAG2) was associated with plasma FFA and glycerol measurements (1.4*10-9 ≤ P ≤ 1.2*10-5), visceral adipose tissue mass (P = 0.0326), and proinsulin conversion (P ≤ 0.0272). The more lipolysis-increasing alleles a subject had, the lower was the visceral fat mass and the lower the proinsulin conversion. CONCLUSIONS: We found evidence for a genetic basis of adipose tissue lipolysis resulting from common SNPs in CIDEA, AMP-activated protein kinase subunits, and cAMP signaling components. A genetic score of lipolysis-increasing alleles determined lower visceral fat mass and lower proinsulin conversion.