nan Hanson

A potential mechanism for impaired vasorelaxation in a dietary model of metabolic syndrome

Poor early growth confers an increased risk of developing type 2 diabetes, hypertension, and other features of the metabolic syndrome in later life. This may result from a mismatch during early life exerting permanent effects on the structure and function of key metabolic organ systems, including the vasculature. Mice (C57BL/J) were exposed to either anhigh fat (HF, 45% kcal fat) or standard animal chow (C, 21% kcal fat) diet throughout pregnancy and lactation. Male offspring were then continued on the same diet as their dams or crossed over onto the alternative diet, for 10 to 12 weeks post weaning. Those fed the HF diet post weaning (HF/HF and C/HF groups) gained more weight and had a higher blood pressure than the C/C and HF/C animals. They also showed an impaired endothelium-dependent relaxation to ACh and higher basal NO production (P<0.05). Our preliminary data demonstrate the impact of an in utero and postnatal HF diet on vascular function through an impairment of NO production and/or bioavailability. It further suggests that both predisposition to disease, acquired in early life, and later lifestyle may contribute to the development of cardiovascular disease which are sustained into adulthood.Poor early growth confers an increased risk of developing type 2 diabetes, hypertension, and other features of the metabolic syndrome in later life. This may result from a mismatch during early life exerting permanent effects on the structure and function of key metabolic organ systems, including the vasculature. Mice (C57BL/J) were exposed to either anhigh fat (HF, 45% kcal fat) or standard animal chow (C, 21% kcal fat) diet throughout pregnancy and lactation. Male offspring were then continued on the same diet as their dams or crossed over onto the alternative diet, for 10 to 12 weeks post weaning. Those fed the HF diet post weaning (HF/HF and C/HF groups) gained more weight and had a higher blood pressure than the C/C and HF/C animals. They also showed an impaired endothelium-dependent relaxation to ACh and higher basal NO production (P<0.05). Our preliminary data demonstrate the impact of an in utero and postnatal HF diet on vascular function through an impairment of NO production and/or bioavailability. It further suggests that both predisposition to disease, acquired in early life, and later lifestyle may contribute to the development of cardiovascular disease which are sustained into adulthood.

Statin treatment improves endothelial function in offspring of protein restricted dams

s of the 57th Meeting of the British Microcirculation Society 2–3 April 2007, Queen’s University of Belfast, Belfast, UK EDITOR: NEENA KALIA, PhD Birmingham, UK Symposium on Diabetic Retinopathy: Pathogenesis and Novel TherapiesMetabolic syndrome is a combination of risk factors that increase risk of cardiovascular disease (CVD) and diabetes. Wenhave assessed muscle microvascular function in 38 consented volunteers [52+/-9y, n=17 male] with two or more features ofnmetabolic syndrome (central obesity, dyslipidaemia, high blood pressure and dysglycaemia), before and after 6 months lipidnlowering therapy (Atorvastatin 40mg o.d.) or placebo control. Filtration capacity (Kf), isovolumetric pressure (Pvi) and restingnlimb blood flow (Qa) were measured using strain gauge plethysmography (FiltrassAngio®, Compumedics.dwl, Germany). Atnbaseline, Kf was negatively correlated with overall CVD risk, visceral fat, insulin resistance, LDL Cholesterol, HbA1c,markersnof inflammation and age (r>0.4, p<0.05), and positively correlated with HDL cholesterol. Qa was related to activity (r=0.42,np=0.03). These individuals also showed a marked decrease in dilator capacity. While statins lowered LDL cholesteroln(P<0.0001), they had little effect on any of our microvascular measures. These data suggest an attenuation in capacity fornblood/tissue exchange in people with features of metabolic syndrome. Although statins are known to decrease risk of CVD,nwe were unable to show any improvements in microvascular function over the 6 months study.

Circulating glucose affects vascular reactivity in late gestation sheep fetuses

Objectives: We have previously shown that cyclin G1nexpression is reduced in fetal hearts after in utero proteinnrestriction (PR) suggesting reduced cardiac cell cycle.nHowever no difference in cyclin G1 expression was seen innadult offspring hearts. We hypothesised that the hearts of adult PR group should be under greater stress to maintainncardiac output. We therefore measured brain natriureticnpeptide (BNP) expression in fetal hearts and left ventriclesnof adult offspring in the control (C) and PR groups becausenBNP is a marker of left ventricular dysfunction during volumenoverload or cardiac fibrosis (Nishikimi et al. Cardiovasc Res.n2006). Methods and results: Pregnant CD1 mice were placed on Cn(18% casein) or PR (9% casein) diet. Fetal hearts werencollected on day 12 of gestation (C, n =11, PR, n =10) andnthe left ventricles (LV) of adult offspring at 6 months (C,nn =17, PR, n =17). Fetal heart BNP mRNA expression relativento unit total RNA as measured by real-time PCR was similarnin C and PR (C, 0.858F0.104 vs. PR, 0.761F0.096, p =NS).nHowever, BNP expression in adult LV was greater in the PRnthan C (C, 7.043F0.68 vs. PR, 11.012F1.54, p =0.04). Conclusion: These results indicate that protein restrictionnin pregnancy induces cellular changes (indicated by cyclinnG1 changes) in the fetal heart which places it under stress innadulthood (elevated BNP production). Because BNP cannsuppress ventricular remodelling, we are presently investigatingncardiac structural changes to assess whether thesenalterations are adaptive or maladaptive.Objectives: Multiple pregnancy affects size at birth andngrowth pattern from as early as 8 weeks gestation (Iffy etnal., 1983. Am. J. Obstet. Gynecol. 146, 970—972). Malenembryos grow at a greater rate than females (Pedersen,n1980. Br. Med. J. 281, 1253). We hypothesised thatnmoderate maternal undernutrion in early gestation willnhave a greater effect on male offspring growth, particularlynif combined with the increased constraint of being a twin.nMethods: Welsh Mountain ewes received 100% (C, n =41) orn50% nutrient requirements (U, n =47) from 1 to 31 daysngestation (dGA), and 100% thereafter. Ewes were weighednweekly and blood samples were collected at 1, 30, and 65ndGA for cortisol analysis (Immulite analyser, DPC).nResults: At day 31, U ewes had gained less weight than Cnewes and had a lower plasma cortisol concentrationn( p b0.05). During 1—31 dGA, twin bearing ewes gained lessnweight than singleton bearing ewes. At birth, twins werensmaller than singleton lambs ( p b0.05). Weight gainednbetween birth and 12 weeks old and weight at 12 weeksnold were greater in U males compared to C males, an effectnthat was predominantly in twins ( p b0.01). Data werenanalysed by ANOVA.nConclusion: The increased constraint of being a twin and anmale embryo in a nutrient-restricted intrauterine environmentninduces a phenotype more likely to gain weight in angood postnatal environment.nSupported by the British Heart Foundation.

Feeding a protein-restricted diet during pregnancy in the rat induces changes to DNA methylation in the liver of the F-1 and F-2 offspring after weaning.

In healthy individuals, glucose and fatty acids are substrates for ATP generation in the heart. There is emerging evidencenfrom patients with type 2 diabetes mellitus that preferential use of fatty acid b-oxidation for energy production may benlinked to cardiomyopathy (Fink, 2004). PPARa activity is important for regulating fatty acid b-oxidation in the heart andnis increased in hearts of rats with experimentally induced diabetes (Fink, 2004). Prenatal undernutrition is relatedninversely to risk of type 2 diabetes mellitus in man (Poole & Byrne, 2005) and insulin resistance in rats (Bertram &nHanson, 2001). We have shown that maternal dietary protein restriction induces persistent alterations to hepatic andncarbohydrate metabolism in the offspring by altering the epigenetic regulation of PPARa and the glucocorticoid receptorn(GR) (Lillycrop et al. 2005). Here we have tested the hypothesis that prenatal protein restriction inducesnhypomethylation of the GR and PPARa promoters in the heart, and that this is prevented by supplementation of thenprotein-restricted (PR) diet with folic acid.Induction of a modified metabolic phenotype in the offspring by feeding a protein-restricted (PR) diet during pregnancy in the rat involves DNA hypomethylation and altered covalent histone modifications leading to increased expression of specific genes (Lillycrop et al. 2005a,b). Hypomethylation of gene promoters may be achieved by impaired DNA methylation de novo, loss of CpG methylation during mitosis, or active demethylation. Histone modifications which modulate transcription involve binding of methyl CpG binding protein (MeCP)-2 to methylated DNA and recruitment of histone-modifying enzymes (Bird, 2002). We investigated in the offspring the effect of feeding a PR diet during pregnancy on the expression of hepatic DNA methyltransferase (DMNT) 1 which maintains CpG methylation, DNMT 3a and 3b which catalyse DNA methylation de novo and the DNA demethylase MBD2.

The effect of dietary protein restriction in pregnant rats on the expression of DNA methyltransferases and methyl CpG binding protein 2 in the liver after weaning

In healthy individuals, glucose and fatty acids are substrates for ATP generation in the heart. There is emerging evidencenfrom patients with type 2 diabetes mellitus that preferential use of fatty acid b-oxidation for energy production may benlinked to cardiomyopathy (Fink, 2004). PPARa activity is important for regulating fatty acid b-oxidation in the heart andnis increased in hearts of rats with experimentally induced diabetes (Fink, 2004). Prenatal undernutrition is relatedninversely to risk of type 2 diabetes mellitus in man (Poole & Byrne, 2005) and insulin resistance in rats (Bertram &nHanson, 2001). We have shown that maternal dietary protein restriction induces persistent alterations to hepatic andncarbohydrate metabolism in the offspring by altering the epigenetic regulation of PPARa and the glucocorticoid receptorn(GR) (Lillycrop et al. 2005). Here we have tested the hypothesis that prenatal protein restriction inducesnhypomethylation of the GR and PPARa promoters in the heart, and that this is prevented by supplementation of thenprotein-restricted (PR) diet with folic acid.Induction of a modified metabolic phenotype in the offspring by feeding a protein-restricted (PR) diet during pregnancy in the rat involves DNA hypomethylation and altered covalent histone modifications leading to increased expression of specific genes (Lillycrop et al. 2005a,b). Hypomethylation of gene promoters may be achieved by impaired DNA methylation de novo, loss of CpG methylation during mitosis, or active demethylation. Histone modifications which modulate transcription involve binding of methyl CpG binding protein (MeCP)-2 to methylated DNA and recruitment of histone-modifying enzymes (Bird, 2002). We investigated in the offspring the effect of feeding a PR diet during pregnancy on the expression of hepatic DNA methyltransferase (DMNT) 1 which maintains CpG methylation, DNMT 3a and 3b which catalyse DNA methylation de novo and the DNA demethylase MBD2.

Hypothalamo-pituitary-adrenal axis responsiveness in adult sheep following early life nutrient restriction

Objectives: We have previously shown that cyclin G1nexpression is reduced in fetal hearts after in utero proteinnrestriction (PR) suggesting reduced cardiac cell cycle.nHowever no difference in cyclin G1 expression was seen innadult offspring hearts. We hypothesised that the hearts of adult PR group should be under greater stress to maintainncardiac output. We therefore measured brain natriureticnpeptide (BNP) expression in fetal hearts and left ventriclesnof adult offspring in the control (C) and PR groups becausenBNP is a marker of left ventricular dysfunction during volumenoverload or cardiac fibrosis (Nishikimi et al. Cardiovasc Res.n2006). Methods and results: Pregnant CD1 mice were placed on Cn(18% casein) or PR (9% casein) diet. Fetal hearts werencollected on day 12 of gestation (C, n =11, PR, n =10) andnthe left ventricles (LV) of adult offspring at 6 months (C,nn =17, PR, n =17). Fetal heart BNP mRNA expression relativento unit total RNA as measured by real-time PCR was similarnin C and PR (C, 0.858F0.104 vs. PR, 0.761F0.096, p =NS).nHowever, BNP expression in adult LV was greater in the PRnthan C (C, 7.043F0.68 vs. PR, 11.012F1.54, p =0.04). Conclusion: These results indicate that protein restrictionnin pregnancy induces cellular changes (indicated by cyclinnG1 changes) in the fetal heart which places it under stress innadulthood (elevated BNP production). Because BNP cannsuppress ventricular remodelling, we are presently investigatingncardiac structural changes to assess whether thesenalterations are adaptive or maladaptive.Objectives: Multiple pregnancy affects size at birth andngrowth pattern from as early as 8 weeks gestation (Iffy etnal., 1983. Am. J. Obstet. Gynecol. 146, 970—972). Malenembryos grow at a greater rate than females (Pedersen,n1980. Br. Med. J. 281, 1253). We hypothesised thatnmoderate maternal undernutrion in early gestation willnhave a greater effect on male offspring growth, particularlynif combined with the increased constraint of being a twin.nMethods: Welsh Mountain ewes received 100% (C, n =41) orn50% nutrient requirements (U, n =47) from 1 to 31 daysngestation (dGA), and 100% thereafter. Ewes were weighednweekly and blood samples were collected at 1, 30, and 65ndGA for cortisol analysis (Immulite analyser, DPC).nResults: At day 31, U ewes had gained less weight than Cnewes and had a lower plasma cortisol concentrationn( p b0.05). During 1—31 dGA, twin bearing ewes gained lessnweight than singleton bearing ewes. At birth, twins werensmaller than singleton lambs ( p b0.05). Weight gainednbetween birth and 12 weeks old and weight at 12 weeksnold were greater in U males compared to C males, an effectnthat was predominantly in twins ( p b0.01). Data werenanalysed by ANOVA.nConclusion: The increased constraint of being a twin and anmale embryo in a nutrient-restricted intrauterine environmentninduces a phenotype more likely to gain weight in angood postnatal environment.nSupported by the British Heart Foundation.

Sex and twinning influence early gestation undernutrition effects on sheep offspring growth

Objectives: We have previously shown that cyclin G1nexpression is reduced in fetal hearts after in utero proteinnrestriction (PR) suggesting reduced cardiac cell cycle.nHowever no difference in cyclin G1 expression was seen innadult offspring hearts. We hypothesised that the hearts of adult PR group should be under greater stress to maintainncardiac output. We therefore measured brain natriureticnpeptide (BNP) expression in fetal hearts and left ventriclesnof adult offspring in the control (C) and PR groups becausenBNP is a marker of left ventricular dysfunction during volumenoverload or cardiac fibrosis (Nishikimi et al. Cardiovasc Res.n2006). Methods and results: Pregnant CD1 mice were placed on Cn(18% casein) or PR (9% casein) diet. Fetal hearts werencollected on day 12 of gestation (C, n =11, PR, n =10) andnthe left ventricles (LV) of adult offspring at 6 months (C,nn =17, PR, n =17). Fetal heart BNP mRNA expression relativento unit total RNA as measured by real-time PCR was similarnin C and PR (C, 0.858F0.104 vs. PR, 0.761F0.096, p =NS).nHowever, BNP expression in adult LV was greater in the PRnthan C (C, 7.043F0.68 vs. PR, 11.012F1.54, p =0.04). Conclusion: These results indicate that protein restrictionnin pregnancy induces cellular changes (indicated by cyclinnG1 changes) in the fetal heart which places it under stress innadulthood (elevated BNP production). Because BNP cannsuppress ventricular remodelling, we are presently investigatingncardiac structural changes to assess whether thesenalterations are adaptive or maladaptive.Objectives: Multiple pregnancy affects size at birth andngrowth pattern from as early as 8 weeks gestation (Iffy etnal., 1983. Am. J. Obstet. Gynecol. 146, 970—972). Malenembryos grow at a greater rate than females (Pedersen,n1980. Br. Med. J. 281, 1253). We hypothesised thatnmoderate maternal undernutrion in early gestation willnhave a greater effect on male offspring growth, particularlynif combined with the increased constraint of being a twin.nMethods: Welsh Mountain ewes received 100% (C, n =41) orn50% nutrient requirements (U, n =47) from 1 to 31 daysngestation (dGA), and 100% thereafter. Ewes were weighednweekly and blood samples were collected at 1, 30, and 65ndGA for cortisol analysis (Immulite analyser, DPC).nResults: At day 31, U ewes had gained less weight than Cnewes and had a lower plasma cortisol concentrationn( p b0.05). During 1—31 dGA, twin bearing ewes gained lessnweight than singleton bearing ewes. At birth, twins werensmaller than singleton lambs ( p b0.05). Weight gainednbetween birth and 12 weeks old and weight at 12 weeksnold were greater in U males compared to C males, an effectnthat was predominantly in twins ( p b0.01). Data werenanalysed by ANOVA.nConclusion: The increased constraint of being a twin and anmale embryo in a nutrient-restricted intrauterine environmentninduces a phenotype more likely to gain weight in angood postnatal environment.nSupported by the British Heart Foundation.

Endothelial dysfunction in aged rats following nutrient restriction in utero [In special abstracts issue]

Objectives: We have previously shown that cyclin G1nexpression is reduced in fetal hearts after in utero proteinnrestriction (PR) suggesting reduced cardiac cell cycle.nHowever no difference in cyclin G1 expression was seen innadult offspring hearts. We hypothesised that the hearts of adult PR group should be under greater stress to maintainncardiac output. We therefore measured brain natriureticnpeptide (BNP) expression in fetal hearts and left ventriclesnof adult offspring in the control (C) and PR groups becausenBNP is a marker of left ventricular dysfunction during volumenoverload or cardiac fibrosis (Nishikimi et al. Cardiovasc Res.n2006). Methods and results: Pregnant CD1 mice were placed on Cn(18% casein) or PR (9% casein) diet. Fetal hearts werencollected on day 12 of gestation (C, n =11, PR, n =10) andnthe left ventricles (LV) of adult offspring at 6 months (C,nn =17, PR, n =17). Fetal heart BNP mRNA expression relativento unit total RNA as measured by real-time PCR was similarnin C and PR (C, 0.858F0.104 vs. PR, 0.761F0.096, p =NS).nHowever, BNP expression in adult LV was greater in the PRnthan C (C, 7.043F0.68 vs. PR, 11.012F1.54, p =0.04). Conclusion: These results indicate that protein restrictionnin pregnancy induces cellular changes (indicated by cyclinnG1 changes) in the fetal heart which places it under stress innadulthood (elevated BNP production). Because BNP cannsuppress ventricular remodelling, we are presently investigatingncardiac structural changes to assess whether thesenalterations are adaptive or maladaptive.Objectives: Multiple pregnancy affects size at birth andngrowth pattern from as early as 8 weeks gestation (Iffy etnal., 1983. Am. J. Obstet. Gynecol. 146, 970—972). Malenembryos grow at a greater rate than females (Pedersen,n1980. Br. Med. J. 281, 1253). We hypothesised thatnmoderate maternal undernutrion in early gestation willnhave a greater effect on male offspring growth, particularlynif combined with the increased constraint of being a twin.nMethods: Welsh Mountain ewes received 100% (C, n =41) orn50% nutrient requirements (U, n =47) from 1 to 31 daysngestation (dGA), and 100% thereafter. Ewes were weighednweekly and blood samples were collected at 1, 30, and 65ndGA for cortisol analysis (Immulite analyser, DPC).nResults: At day 31, U ewes had gained less weight than Cnewes and had a lower plasma cortisol concentrationn( p b0.05). During 1—31 dGA, twin bearing ewes gained lessnweight than singleton bearing ewes. At birth, twins werensmaller than singleton lambs ( p b0.05). Weight gainednbetween birth and 12 weeks old and weight at 12 weeksnold were greater in U males compared to C males, an effectnthat was predominantly in twins ( p b0.01). Data werenanalysed by ANOVA.nConclusion: The increased constraint of being a twin and anmale embryo in a nutrient-restricted intrauterine environmentninduces a phenotype more likely to gain weight in angood postnatal environment.nSupported by the British Heart Foundation.

Early gestation undernutrition causes increased expression of myosin light chain kinase in adult sheep coronary arteries [In special abstracts issue]

Objectives: We have previously shown that cyclin G1nexpression is reduced in fetal hearts after in utero proteinnrestriction (PR) suggesting reduced cardiac cell cycle.nHowever no difference in cyclin G1 expression was seen innadult offspring hearts. We hypothesised that the hearts of adult PR group should be under greater stress to maintainncardiac output. We therefore measured brain natriureticnpeptide (BNP) expression in fetal hearts and left ventriclesnof adult offspring in the control (C) and PR groups becausenBNP is a marker of left ventricular dysfunction during volumenoverload or cardiac fibrosis (Nishikimi et al. Cardiovasc Res.n2006). Methods and results: Pregnant CD1 mice were placed on Cn(18% casein) or PR (9% casein) diet. Fetal hearts werencollected on day 12 of gestation (C, n =11, PR, n =10) andnthe left ventricles (LV) of adult offspring at 6 months (C,nn =17, PR, n =17). Fetal heart BNP mRNA expression relativento unit total RNA as measured by real-time PCR was similarnin C and PR (C, 0.858F0.104 vs. PR, 0.761F0.096, p =NS).nHowever, BNP expression in adult LV was greater in the PRnthan C (C, 7.043F0.68 vs. PR, 11.012F1.54, p =0.04). Conclusion: These results indicate that protein restrictionnin pregnancy induces cellular changes (indicated by cyclinnG1 changes) in the fetal heart which places it under stress innadulthood (elevated BNP production). Because BNP cannsuppress ventricular remodelling, we are presently investigatingncardiac structural changes to assess whether thesenalterations are adaptive or maladaptive.Objectives: Multiple pregnancy affects size at birth andngrowth pattern from as early as 8 weeks gestation (Iffy etnal., 1983. Am. J. Obstet. Gynecol. 146, 970—972). Malenembryos grow at a greater rate than females (Pedersen,n1980. Br. Med. J. 281, 1253). We hypothesised thatnmoderate maternal undernutrion in early gestation willnhave a greater effect on male offspring growth, particularlynif combined with the increased constraint of being a twin.nMethods: Welsh Mountain ewes received 100% (C, n =41) orn50% nutrient requirements (U, n =47) from 1 to 31 daysngestation (dGA), and 100% thereafter. Ewes were weighednweekly and blood samples were collected at 1, 30, and 65ndGA for cortisol analysis (Immulite analyser, DPC).nResults: At day 31, U ewes had gained less weight than Cnewes and had a lower plasma cortisol concentrationn( p b0.05). During 1—31 dGA, twin bearing ewes gained lessnweight than singleton bearing ewes. At birth, twins werensmaller than singleton lambs ( p b0.05). Weight gainednbetween birth and 12 weeks old and weight at 12 weeksnold were greater in U males compared to C males, an effectnthat was predominantly in twins ( p b0.01). Data werenanalysed by ANOVA.nConclusion: The increased constraint of being a twin and anmale embryo in a nutrient-restricted intrauterine environmentninduces a phenotype more likely to gain weight in angood postnatal environment.nSupported by the British Heart Foundation.