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Genes of antioxidant defence and diadetes mellitus
Track 4. Basic Research
s177
P6%
P698
Genes of Antioxidant Defence and Diadetes Mellitus IVAN I. DEDOV’, Dmitry A. Chistyakov’, Kirill V. Savost’yanov’, Rustam I. Turakulov2, Tamara L. Kuraeva’,Valery V. Nosikov’. ’ Endocn’nology Research Cenrre, Moscow, Russian Federation: z National Research Cenrre “GosNII gene&a” Moscow, Russian Federation
Failure of Compensatory Beta-Cell Hyperplasia in Response to Insulin Resistance Plays a Crudal Role in the Development of Qpe 2 Diabetes YASUO TERAUCHI’, Kajuro Komeda2, Naoto Kubota’, Kazuhiro Eto ’ , Yoshiharu Tsubamoto ’ , Kazuyuki Tobe ’ , Yasuo Akanuma3, Takashi Kadowaki ’ ’ Deparrmenr of Metabolic Diseases, Graduate School of Medicine, Tokyo,Japan: ‘Division of Laborarory Animal Science, Animal Research Center, TokyoMedical University,Tokyo,Japan; 3 Instirurefor Diabetes Care and Research, Asahi Life Foundarion, Tokyo,Japan
Oxidative stress is known to intensify under diabetic conditions. Antioxidant enzymes that reduce excess of free oxygen radicals and peroxides may be involve into development of diabetes mellitus (DM). Allele and genotype frequencies of three polymorphic markers located at (Cl 167T mutation) or nearby (microsatellites Dl 1S907 and Dl 1S2008) the cat&se (CAT) gene and D6S392 locus near Mn-dependent superoxide dismutase (SOD2) gene were determined in healthy controls (n=132), IDDM (n=134) and NIDDM (n=154) patients. For DllS2008, significant difference in frequency of 4 alleles and 8 genotypes between IDDM and non-diabetic subjects as well as in frequency of 5 alleles and 7 genotypes between NlDDM group and the controls was observed. In IDDM patients, frequency of both 3 alleles and 4 genotypes of DllS907 was significantly changed in comparison with healthy donors. Significant changes in frequency of 5 alleles and 6 alleles of Dl IS907 were shown to be in NIDDM patients compared to the controls. For D6S392, portion of 6 and 8 alleles was markedly differed in IDDM and NIDDM patients respectively in comparison with non-affected subjects. C allele and CC genotype of the Cl 167T CAT gene were significantly increased in diabetic patients in comparison with the controls while T allele and ‘IT genotype were decreased. Thus, CAT and SOD2 genes may be strongly associated with DM pathogenesis in a Moscow population.
P697 MisseaseMutations in the Insulin Promoter Factor-l Gene in a Healthy German Population Are Not Associated with Decreased Insulin Secretion FAUST0 E. MACHICAO, Andreas Fritsche, Michael Stumvoll, Melanie Weisser, Alke Rettig, Erwin Scleicher, Hans Uhich Haering. Medizinische Klinik IV Universtyof Tuebingen, Germany Mutations in the insulin promoter factor 1 (Mody4) gene are associated with MODY diabetes. The molecular mechanism e.g. loss of function by which mutations in IPF-1 cause diabetes is unknown. We studied the role of IPF-1 in 221 German normal glucose tolerant subjects undergoing an OGTT (N=221) and a hyperglycemic clamp (N=38). We found a novel IPF-1 missense mutation L82F affecting 22% of this population. The previously described D76N mutation was present in 2% of this population. Exon 1 was amplified using specific primers. Genotyping of the L82Fand D76N substitution was examined by direct sequencing of the amplified polymerase chain reaction products using an ABI PRISM 310 Genetic Analyzer. Insulin secretion (estimated as AUCIns/AUCGluc from the OGTI’) was not different in the D76N (65.1 f 16.7 pM/mM) and L82F groups (43.5 f 3.8 pM/mM) vs the wildtypes D76D (45.2 f 2.0 pM/mM, p=O.6)) and L82L (46.2 f 2.3 pM/mM, p=O.2). lst/2nd phase insulin secretion (determined from C-peptide by deconvolution)during the hyperglycemic clamp were also not different (~‘0.7) in the L82F group (n=7) (2589 f 560/688 f 73 pmolxmin-1) vs the wildtype L82L (n=31) (2309 f 2561658 f 64 pmolxmin-1). These data suggest that neither the L82F nor the D76N mutation in exon 1 of IPF-1 are associated with impaired insulin secretion in this population. It therefore appears unlikely that they contribute to the development of type II diabetes. The functional relevance of the mutation L82F in exon 1 remains to be established.
The pathogenesis of human type 2 diabetes is characterized by two major features: peripheral insulin resistance and impaired insulin secretion from pancreatic beta cells. To investigate the interactions between insulin resistance and insulin secretory defect in the development of type 2 diabetes, we investigated IRS-l- and IRS-2-knockout mice. At 6 weeks of age, although IRS-I-‘- and IRS-2.‘. were insulin resistant, they showed minimally impaired glucose tolerance due to compensatory hyperinsulinemia. Histological analysis revealed that beta-cell mass was increased by 85% in IRS-Z’. and reduced by 17% in IRS-Z’- comp;iled with wild-type mice. At 10 weeks of age, while IRS-l-‘- kept minimally impaired glucose tolerance, IRS-Z-‘-developed marked glucose intolerance. We also studied the effect of high-fat (HF) diet-induced insulin resistance in wild-type and heterozygous beta-cell glucokinase knockout mice (Gck”.) with impaired glucose tolerance due to mildly decreased insulin secretion to glucose. Both mouse groups became insulin resistant under a HF diet. However, wild-type mice under a HF diet kept normal glucose tolerance due to compensatory hyperinsulinemia after 4 weeks of diet. In contrast, Gck’/- under a I-IF diet developed type 2 diabetes due to a lack of compensatory hyperinsulinemia. Although wild-type mice under a HF diet developed impaired glucose tolerance by 16 weeks, they never developed type 2 diabetes unlike Gck +‘- under a HF diet. While beta-cell mass was increased by 110% in wild-type mice under a I-IF diet, there was no such beta-cell hyperplasia in Gck’l- under a HF diet. Taken together, failure of compensatory beta-cell hyperplasia in response to either genetically-determined or HF diet-induced insulin resistance plays a crucial role in the development of type 2 diabetes.
P699 Leucine 7 to Proline 7 Polymorphism in the Neuropeptide Y Gene Is Not Associated with Cholesterol Concentrations or Blood Pressure in Qpe 2 Diabetic Subjects MATTE K. KARVONEN ’ , Markku Koulu ’ , Aila Rissanen *, Ulla Pesonen ‘, Matti I.J. Uusitupa3. I Dep. of Pharmacology and Clinical Pharmacology, Universityof Turku, Turku, Finland; 2 Earing Disorder Unit, Universityof Helsinki, Helsinki, Finland: 3 Department of Clinical Nurririon, Universityof Kuopio, Kuopio, Finland We have recently demonstrated that subjects having Pro7 in the signal peptide of neuropeptide Y (NPY) have higher serum cholesterol and apolipoprotein B levels when compared to individuals having wildtype (Le.u7/Leu7) signal peptide sequence. We investigated the association of Leu7Pro polymorphism with cholesterol concentrations and blood pressure in type 2 diabetic subjects. The study population consisted of 208 (121 females + 87 males). There were no differences in serum cholesterol concentrations, blood pressure or medications between the two genotype groups (Leu/Leu and Pro/-) of subjects. In conclusion, in type 2 diabetic subjects Leu7Pro polymorphism seems not to be associated with serum cholesterol concentrations or with blood pressure level. The lack of association could be due to quite a prevalently used medication or to altered cholesterol metabolism associated with type 2 diabetes.
s177
P6%
P698
Genes of Antioxidant Defence and Diadetes Mellitus IVAN I. DEDOV’, Dmitry A. Chistyakov’, Kirill V. Savost’yanov’, Rustam I. Turakulov2, Tamara L. Kuraeva’,Valery V. Nosikov’. ’ Endocn’nology Research Cenrre, Moscow, Russian Federation: z National Research Cenrre “GosNII gene&a” Moscow, Russian Federation
Failure of Compensatory Beta-Cell Hyperplasia in Response to Insulin Resistance Plays a Crudal Role in the Development of Qpe 2 Diabetes YASUO TERAUCHI’, Kajuro Komeda2, Naoto Kubota’, Kazuhiro Eto ’ , Yoshiharu Tsubamoto ’ , Kazuyuki Tobe ’ , Yasuo Akanuma3, Takashi Kadowaki ’ ’ Deparrmenr of Metabolic Diseases, Graduate School of Medicine, Tokyo,Japan: ‘Division of Laborarory Animal Science, Animal Research Center, TokyoMedical University,Tokyo,Japan; 3 Instirurefor Diabetes Care and Research, Asahi Life Foundarion, Tokyo,Japan
Oxidative stress is known to intensify under diabetic conditions. Antioxidant enzymes that reduce excess of free oxygen radicals and peroxides may be involve into development of diabetes mellitus (DM). Allele and genotype frequencies of three polymorphic markers located at (Cl 167T mutation) or nearby (microsatellites Dl 1S907 and Dl 1S2008) the cat&se (CAT) gene and D6S392 locus near Mn-dependent superoxide dismutase (SOD2) gene were determined in healthy controls (n=132), IDDM (n=134) and NIDDM (n=154) patients. For DllS2008, significant difference in frequency of 4 alleles and 8 genotypes between IDDM and non-diabetic subjects as well as in frequency of 5 alleles and 7 genotypes between NlDDM group and the controls was observed. In IDDM patients, frequency of both 3 alleles and 4 genotypes of DllS907 was significantly changed in comparison with healthy donors. Significant changes in frequency of 5 alleles and 6 alleles of Dl IS907 were shown to be in NIDDM patients compared to the controls. For D6S392, portion of 6 and 8 alleles was markedly differed in IDDM and NIDDM patients respectively in comparison with non-affected subjects. C allele and CC genotype of the Cl 167T CAT gene were significantly increased in diabetic patients in comparison with the controls while T allele and ‘IT genotype were decreased. Thus, CAT and SOD2 genes may be strongly associated with DM pathogenesis in a Moscow population.
P697 MisseaseMutations in the Insulin Promoter Factor-l Gene in a Healthy German Population Are Not Associated with Decreased Insulin Secretion FAUST0 E. MACHICAO, Andreas Fritsche, Michael Stumvoll, Melanie Weisser, Alke Rettig, Erwin Scleicher, Hans Uhich Haering. Medizinische Klinik IV Universtyof Tuebingen, Germany Mutations in the insulin promoter factor 1 (Mody4) gene are associated with MODY diabetes. The molecular mechanism e.g. loss of function by which mutations in IPF-1 cause diabetes is unknown. We studied the role of IPF-1 in 221 German normal glucose tolerant subjects undergoing an OGTT (N=221) and a hyperglycemic clamp (N=38). We found a novel IPF-1 missense mutation L82F affecting 22% of this population. The previously described D76N mutation was present in 2% of this population. Exon 1 was amplified using specific primers. Genotyping of the L82Fand D76N substitution was examined by direct sequencing of the amplified polymerase chain reaction products using an ABI PRISM 310 Genetic Analyzer. Insulin secretion (estimated as AUCIns/AUCGluc from the OGTI’) was not different in the D76N (65.1 f 16.7 pM/mM) and L82F groups (43.5 f 3.8 pM/mM) vs the wildtypes D76D (45.2 f 2.0 pM/mM, p=O.6)) and L82L (46.2 f 2.3 pM/mM, p=O.2). lst/2nd phase insulin secretion (determined from C-peptide by deconvolution)during the hyperglycemic clamp were also not different (~‘0.7) in the L82F group (n=7) (2589 f 560/688 f 73 pmolxmin-1) vs the wildtype L82L (n=31) (2309 f 2561658 f 64 pmolxmin-1). These data suggest that neither the L82F nor the D76N mutation in exon 1 of IPF-1 are associated with impaired insulin secretion in this population. It therefore appears unlikely that they contribute to the development of type II diabetes. The functional relevance of the mutation L82F in exon 1 remains to be established.
The pathogenesis of human type 2 diabetes is characterized by two major features: peripheral insulin resistance and impaired insulin secretion from pancreatic beta cells. To investigate the interactions between insulin resistance and insulin secretory defect in the development of type 2 diabetes, we investigated IRS-l- and IRS-2-knockout mice. At 6 weeks of age, although IRS-I-‘- and IRS-2.‘. were insulin resistant, they showed minimally impaired glucose tolerance due to compensatory hyperinsulinemia. Histological analysis revealed that beta-cell mass was increased by 85% in IRS-Z’. and reduced by 17% in IRS-Z’- comp;iled with wild-type mice. At 10 weeks of age, while IRS-l-‘- kept minimally impaired glucose tolerance, IRS-Z-‘-developed marked glucose intolerance. We also studied the effect of high-fat (HF) diet-induced insulin resistance in wild-type and heterozygous beta-cell glucokinase knockout mice (Gck”.) with impaired glucose tolerance due to mildly decreased insulin secretion to glucose. Both mouse groups became insulin resistant under a HF diet. However, wild-type mice under a HF diet kept normal glucose tolerance due to compensatory hyperinsulinemia after 4 weeks of diet. In contrast, Gck’/- under a I-IF diet developed type 2 diabetes due to a lack of compensatory hyperinsulinemia. Although wild-type mice under a HF diet developed impaired glucose tolerance by 16 weeks, they never developed type 2 diabetes unlike Gck +‘- under a HF diet. While beta-cell mass was increased by 110% in wild-type mice under a I-IF diet, there was no such beta-cell hyperplasia in Gck’l- under a HF diet. Taken together, failure of compensatory beta-cell hyperplasia in response to either genetically-determined or HF diet-induced insulin resistance plays a crucial role in the development of type 2 diabetes.
P699 Leucine 7 to Proline 7 Polymorphism in the Neuropeptide Y Gene Is Not Associated with Cholesterol Concentrations or Blood Pressure in Qpe 2 Diabetic Subjects MATTE K. KARVONEN ’ , Markku Koulu ’ , Aila Rissanen *, Ulla Pesonen ‘, Matti I.J. Uusitupa3. I Dep. of Pharmacology and Clinical Pharmacology, Universityof Turku, Turku, Finland; 2 Earing Disorder Unit, Universityof Helsinki, Helsinki, Finland: 3 Department of Clinical Nurririon, Universityof Kuopio, Kuopio, Finland We have recently demonstrated that subjects having Pro7 in the signal peptide of neuropeptide Y (NPY) have higher serum cholesterol and apolipoprotein B levels when compared to individuals having wildtype (Le.u7/Leu7) signal peptide sequence. We investigated the association of Leu7Pro polymorphism with cholesterol concentrations and blood pressure in type 2 diabetic subjects. The study population consisted of 208 (121 females + 87 males). There were no differences in serum cholesterol concentrations, blood pressure or medications between the two genotype groups (Leu/Leu and Pro/-) of subjects. In conclusion, in type 2 diabetic subjects Leu7Pro polymorphism seems not to be associated with serum cholesterol concentrations or with blood pressure level. The lack of association could be due to quite a prevalently used medication or to altered cholesterol metabolism associated with type 2 diabetes.