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Prenatal Exposure to Persistent Organic Pollutants and Metabolic Syndrome in a Multi-Generational Rat Model
Abstracts / Can J Diabetes 38 (2014) S29eS74
186 withdrawn
187 Glucagon-Like Peptide-1(9-37) Fusion Proteins Suppress Hepatic Gluconeogenesis in Zebrafish Larva and Mice XIAOMING LI, WANGPING SUN, YOUTONG WANG, JOEY ZHOU, JIN XING, XIAOYAN WEN, QINGHUA WANG Toronto, ON GLP-1(7-37, or 7-36amide), an insulinotrophic hormone is rapidly metabolized by dipeptidyl peptidase-IV (DPP-IV) to form GLP-1(9-37). Recent evidence suggested that GLP-1(9-37) has insulinomimetic effects in a subject. This is supported by clinical studies demonstrating that administration of GLP-1(9-37) in human reduced postprandial glycemia independent of insulin secretion and insulin responsiveness. We hypothesized that the extrapancreatic glucose-lowering effects of GLP-1(9-37) is achieved through the suppression of hepatic gluconeogenesis. We constructed the GLP-1 fusion proteins by the fusion of GLP-1(9-37 or 737) to a human IgG2 Fc segment (9-37/Fc, 7-37/Fc). Microinjection of fluorescein-labelled fusion proteins in zebrafish larva revealed that 7-37/Fc were concentrated in the pancreas and islet, whereas, 9-37/Fc were mainly localized in the liver, suggesting that GLP-1(937) has a distinct pharmacokinetic profile as that of GLP-1(7-37). We conducted qRT-PCR to quantify the transcript expression of PEPCK in the zebrafish injected with the fusion peptides and glucagon (control). We found that 9-37/Fc significantly suppressed PEPCK expression in a time-dependent fashion, while glucagon enhanced and 7-37/Fc reduced these gene expression to certain levels (9-37/Fc vs. Glucagon p<0.001 n¼5; 9-37/Fc vs. 7-37/Fc p<0.01, n¼5). The qRT-PCR was also performed in total RNA extracted from the liver tissues in CD1 mice injected with equal mole GLP-1 fusion proteins and glucagon. We found that 9-37/Fc significantly suppressed hepatic PEPCK expression in mice (9-37/Fc vs. Glucagon p<0.001 n¼5; 9-37/Fc vs. 7-37/Fc p<0.05, n¼5). These findings suggest that the glucose-lowering effects of GLP-1(9-37) is achieved at least in part via suppressing gluconeogenesis in the liver. PEPCK: phosphoenolpyruvate carboxykinase
188 Gestational Diabetes Alters the Hepatic Metabolite Profile and Contributes to Steatosis in Young Rat Offspring TROY PEREIRA, MARIO FONSECA, KRISTYN CAMPBELL, BRITTANY MOYCE, LAURA COLE, GRANT HATCH, MICHEL ALIANI, VERNON DOLINSKY* Winnipeg, MB Background: Gestational diabetes (GDM) is a common complication of pregnancy, but the metabolic alterations underlying the fetal programming effects of GDM are poorly understood. Methods: To induce GDM, female Sprague-Dawley rats were fed a high-fat/sucrose (HFS; 45%) diet prior to mating that caused obesity, glucose intolerance and hyperglycemia during pregnancy. Lean control pregnant rats received low fat (LF; 10%) diets. To investigate the interaction between the prenatal environment and the postnatal diet, rat offspring were randomly assigned to LF or HFS diets for 12 weeks. Glucose and insulin tolerance tests were used to evaluate insulin sensitivity. Alterations in hepatic lipid levels were evaluated by histology and metabolomic analysis using mass spectroscopy. Results: The LF as well as HFS fed young adult offspring of GDM dams gained more weight and were significantly more insulin resistant than the offspring of lean dams. Large lipid droplets were observed in the liver indicating hepatic steatosis in the offspring of GDM dams. Metabolomic analysis of the liver revealed a 10-fold
S67
increase in the lipotoxic lipid, ceramide, and reduced phosphatylethanolamine by w25% in the offspring of GDM dams compared to the offspring of lean dams. In addition, increased acetyl-CoA carboxylase-2 and reduced peroxisomal proliferator activated receptor-a and insulin receptor-b mRNA and protein expression was observed in liver tissues of GDM offspring. Conclusions: Fetal exposure to GDM enhances obesity, hepatic steatosis and insulin resistance in the offspring. Fetal programming of gene expression and hepatic metabolite levels could drive the development of hepatic steatosis and insulin resistance.
189 Prenatal Exposure to Persistent Organic Pollutants and Metabolic Syndrome in a Multi-Generational Rat Model NADINE LEBLANC*, CHARLES LAVIGNE, JANICE BAILEY, HÉLÈNE JACQUES Quebec, QC; La Pocatière, QC Background: Chronic exposure to persistent organic pollutants (POP) is associated with the development of insulin resistance and type 2 diabetes. Objective: The objective was to examine the impact of POP ingestion, at levels mimicking those observed in Quebec Great Northern population, on body weight and composition and glucose metabolism in a pregnant rat model and the 2 following generations. Methods: Sprague-Dawley female rats were exposed by gavage to either an environmentally relevant POP mixture or a control solution (F0; n¼4). Gavage continued during mating to unexposed males and pregnancy. Gavage stopped after birth of the first generation (F1). After weaning F0 females were starved for 12 h and a glucose tolerance test (GTT) was performed. Prenatally treated F1 males were mated to untreated females to produce a second generation (F2). After a 12 h fast, a GTT was performed on F1 males 90 and 180 days after birth and on F2 males 60 and 90 days after birth. After sacrifice, liver, adipose and muscle tissues were collected. Results: In F0 females, no differences due to POP exposure were observed for all measured parameters. In prenatally exposed F1 males, glucose tolerance decreased 90 days after birth, and liver, subcutaneous fat, extensor digitorum longus and soleus muscle weight was reduced 180 days after birth. The F2 males from POPexposed grandmothers were smaller 90 days after birth. Conclusion: Prenatal exposure to POP may cause abnormalities in body weight and composition as well as glucose tolerance that are transmitted from generation to generation by the paternal lineage.
190 Successful Hepatitis C Antiviral Therapy Induces Remission of Type 2 Diabetes: A Case Report MARY-ANNE DOYLE, CURTIS COOPER Ottawa, ON Background: Type 2 diabetes (T2DM) is a well-described extrahepatic manifestation of hepatitis C infection (HCV). Insulin resistance and T2DM in HCV patients are associated with poor response to HCV antiviral therapy, progression of liver fibrosis and increased risk of hepatocellular carcinoma. Eradication of HCV has led to improvements in insulin resistance but to date has not been shown to induce remission of diabetes. Clinical case: We report a case of a 49-year-old man with HCV and a 2-year history of T2DM on oral agents. He was initially treated with peg-interferon/ribavarin (peg-IFN/rib) but did not achieve a HCV treatment response. Four years later, he was retreated with peg-IFN/rib plus an HCV protease inhibitor (boceprevir). His HbA1c at the start of treatment was 7.9%. Antiviral response to HCV therapy correlated with a significant improvement in glucose control. He achieved a sustained virological response and within a year of
186 withdrawn
187 Glucagon-Like Peptide-1(9-37) Fusion Proteins Suppress Hepatic Gluconeogenesis in Zebrafish Larva and Mice XIAOMING LI, WANGPING SUN, YOUTONG WANG, JOEY ZHOU, JIN XING, XIAOYAN WEN, QINGHUA WANG Toronto, ON GLP-1(7-37, or 7-36amide), an insulinotrophic hormone is rapidly metabolized by dipeptidyl peptidase-IV (DPP-IV) to form GLP-1(9-37). Recent evidence suggested that GLP-1(9-37) has insulinomimetic effects in a subject. This is supported by clinical studies demonstrating that administration of GLP-1(9-37) in human reduced postprandial glycemia independent of insulin secretion and insulin responsiveness. We hypothesized that the extrapancreatic glucose-lowering effects of GLP-1(9-37) is achieved through the suppression of hepatic gluconeogenesis. We constructed the GLP-1 fusion proteins by the fusion of GLP-1(9-37 or 737) to a human IgG2 Fc segment (9-37/Fc, 7-37/Fc). Microinjection of fluorescein-labelled fusion proteins in zebrafish larva revealed that 7-37/Fc were concentrated in the pancreas and islet, whereas, 9-37/Fc were mainly localized in the liver, suggesting that GLP-1(937) has a distinct pharmacokinetic profile as that of GLP-1(7-37). We conducted qRT-PCR to quantify the transcript expression of PEPCK in the zebrafish injected with the fusion peptides and glucagon (control). We found that 9-37/Fc significantly suppressed PEPCK expression in a time-dependent fashion, while glucagon enhanced and 7-37/Fc reduced these gene expression to certain levels (9-37/Fc vs. Glucagon p<0.001 n¼5; 9-37/Fc vs. 7-37/Fc p<0.01, n¼5). The qRT-PCR was also performed in total RNA extracted from the liver tissues in CD1 mice injected with equal mole GLP-1 fusion proteins and glucagon. We found that 9-37/Fc significantly suppressed hepatic PEPCK expression in mice (9-37/Fc vs. Glucagon p<0.001 n¼5; 9-37/Fc vs. 7-37/Fc p<0.05, n¼5). These findings suggest that the glucose-lowering effects of GLP-1(9-37) is achieved at least in part via suppressing gluconeogenesis in the liver. PEPCK: phosphoenolpyruvate carboxykinase
188 Gestational Diabetes Alters the Hepatic Metabolite Profile and Contributes to Steatosis in Young Rat Offspring TROY PEREIRA, MARIO FONSECA, KRISTYN CAMPBELL, BRITTANY MOYCE, LAURA COLE, GRANT HATCH, MICHEL ALIANI, VERNON DOLINSKY* Winnipeg, MB Background: Gestational diabetes (GDM) is a common complication of pregnancy, but the metabolic alterations underlying the fetal programming effects of GDM are poorly understood. Methods: To induce GDM, female Sprague-Dawley rats were fed a high-fat/sucrose (HFS; 45%) diet prior to mating that caused obesity, glucose intolerance and hyperglycemia during pregnancy. Lean control pregnant rats received low fat (LF; 10%) diets. To investigate the interaction between the prenatal environment and the postnatal diet, rat offspring were randomly assigned to LF or HFS diets for 12 weeks. Glucose and insulin tolerance tests were used to evaluate insulin sensitivity. Alterations in hepatic lipid levels were evaluated by histology and metabolomic analysis using mass spectroscopy. Results: The LF as well as HFS fed young adult offspring of GDM dams gained more weight and were significantly more insulin resistant than the offspring of lean dams. Large lipid droplets were observed in the liver indicating hepatic steatosis in the offspring of GDM dams. Metabolomic analysis of the liver revealed a 10-fold
S67
increase in the lipotoxic lipid, ceramide, and reduced phosphatylethanolamine by w25% in the offspring of GDM dams compared to the offspring of lean dams. In addition, increased acetyl-CoA carboxylase-2 and reduced peroxisomal proliferator activated receptor-a and insulin receptor-b mRNA and protein expression was observed in liver tissues of GDM offspring. Conclusions: Fetal exposure to GDM enhances obesity, hepatic steatosis and insulin resistance in the offspring. Fetal programming of gene expression and hepatic metabolite levels could drive the development of hepatic steatosis and insulin resistance.
189 Prenatal Exposure to Persistent Organic Pollutants and Metabolic Syndrome in a Multi-Generational Rat Model NADINE LEBLANC*, CHARLES LAVIGNE, JANICE BAILEY, HÉLÈNE JACQUES Quebec, QC; La Pocatière, QC Background: Chronic exposure to persistent organic pollutants (POP) is associated with the development of insulin resistance and type 2 diabetes. Objective: The objective was to examine the impact of POP ingestion, at levels mimicking those observed in Quebec Great Northern population, on body weight and composition and glucose metabolism in a pregnant rat model and the 2 following generations. Methods: Sprague-Dawley female rats were exposed by gavage to either an environmentally relevant POP mixture or a control solution (F0; n¼4). Gavage continued during mating to unexposed males and pregnancy. Gavage stopped after birth of the first generation (F1). After weaning F0 females were starved for 12 h and a glucose tolerance test (GTT) was performed. Prenatally treated F1 males were mated to untreated females to produce a second generation (F2). After a 12 h fast, a GTT was performed on F1 males 90 and 180 days after birth and on F2 males 60 and 90 days after birth. After sacrifice, liver, adipose and muscle tissues were collected. Results: In F0 females, no differences due to POP exposure were observed for all measured parameters. In prenatally exposed F1 males, glucose tolerance decreased 90 days after birth, and liver, subcutaneous fat, extensor digitorum longus and soleus muscle weight was reduced 180 days after birth. The F2 males from POPexposed grandmothers were smaller 90 days after birth. Conclusion: Prenatal exposure to POP may cause abnormalities in body weight and composition as well as glucose tolerance that are transmitted from generation to generation by the paternal lineage.
190 Successful Hepatitis C Antiviral Therapy Induces Remission of Type 2 Diabetes: A Case Report MARY-ANNE DOYLE, CURTIS COOPER Ottawa, ON Background: Type 2 diabetes (T2DM) is a well-described extrahepatic manifestation of hepatitis C infection (HCV). Insulin resistance and T2DM in HCV patients are associated with poor response to HCV antiviral therapy, progression of liver fibrosis and increased risk of hepatocellular carcinoma. Eradication of HCV has led to improvements in insulin resistance but to date has not been shown to induce remission of diabetes. Clinical case: We report a case of a 49-year-old man with HCV and a 2-year history of T2DM on oral agents. He was initially treated with peg-interferon/ribavarin (peg-IFN/rib) but did not achieve a HCV treatment response. Four years later, he was retreated with peg-IFN/rib plus an HCV protease inhibitor (boceprevir). His HbA1c at the start of treatment was 7.9%. Antiviral response to HCV therapy correlated with a significant improvement in glucose control. He achieved a sustained virological response and within a year of