John S Milne

University of Aberdeen, Aberdeen, Scotland, United Kingdom

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Publications (53)202.81 Total impact

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    ABSTRACT: Intrauterine growth restriction (IUGR) is a risk factor for obesity, particularly when offspring are born into an unrestricted nutritional environment. Herein we investigated the impact of IUGR and gender on circulating lipids and on adipogenic, lipogenic and adipokine gene expression in perirenal adipose tissue. Singleton lambs born to overnourished adolescent dams were normal birthweight (N) or IUGR (32% lower birthweight due to placental insufficiency). IUGR lambs exhibited increased fractional growth rates but remained smaller than N at necropsy (d77). At 48d, fasting plasma triglycerides, nonesterified fatty acids and glycerol were elevated predominantly in IUGR males. Body fat content was independent of prenatal growth but higher in females than males. In perirenal fat, relative to male lambs, females had larger adipocytes and lipoprotein lipase, fatty acid synthase and leptin mRNA expression levels were higher while IGF1, IGF2, IGF1R, IGF2R and hormone sensitive lipase mRNAs were lower, and all were independent of prenatal growth category; peroxisome-proliferator-activated receptor-γ and glycerol-3-phosphate dehydrogenase (G3PDH) mRNA expression were not affected by IUGR or gender. Adiposity indices were inversely related to G3PDH mRNA expression, and for the population as a whole the expression of IGF system genes in perirenal fat was negatively correlated with plasma leptin, fat mass and adipocyte size, and positively correlated with circulating IGF1. Higher plasma lipids in IUGR males may predict later adverse metabolic health and obesity, but in early postnatal life gender is the dominant influence on adipose tissue gene expression reflecting the already established sexual dimorphism in body composition.
    Journal of Molecular Endocrinology 06/2014; · 3.58 Impact Factor
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    ABSTRACT: Introduction: Fetal growth restriction (FGR) occurs in ~8% of pregnancies and is a major cause of perinatal mortality and morbidity. There is no effective treatment. FGR is characterised by reduced uterine blood flow (UBF). In normal sheep pregnancies, local uterine artery (UtA) adenovirus (Ad) mediated over-expression of vascular endothelial growth factor (VEGF) increases UBF. Herein we evaluated Ad.VEGF therapy in the overnourished adolescent ewe, an experimental paradigm in which reduced UBF from mid-gestation correlates with reduced lamb birthweight near term. Materials and Methods: Singleton pregnancies were established using embryo transfer in adolescent ewes subsequently offered a high-intake (n=45) or control-intake (n=12) of a complete diet to generate FGR or normal fetoplacental growth, respectively. High-intake ewes were randomised mid-gestation to receive bilateral UtA injections of 5x1011 particles Ad.VEGF-A165 (n=18), control vector Ad.LacZ (n=14) or control saline (n=13). Fetal growth/wellbeing were evaluated using serial ultrasound. UBF was monitored using indwelling flowprobes until necropsy at 0.9 gestation. Vasorelaxation, neovascularisation within the perivascular adventitia and placental mRNA expression of angiogenic factors/receptors were examined using organ bath analysis, anti-vWF immunohistochemistry and qRT-PCR, respectively. Results: Ad.VEGF significantly increased ultrasonographic fetal growth velocity at 3-4 weeks post-injection (p=0.016-0.047). At 0.9 gestation fewer fetuses were markedly growth-restricted (birthweight >2SD below contemporaneous control-intake mean) following Ad.VEGF therapy. There was also evidence of mitigated fetal brain sparing (lower biparietal diameter to abdominal circumference and brain to liver weight ratios). No effects were observed on UBF or neovascularisation, however Ad.VEGF-transduced vessels demonstrated strikingly enhanced vasorelaxation. Placental efficiency (fetal to placental weight ratio) and FLT1/KDR mRNA expression was increased in the maternal but not fetal placental compartments, suggesting downstream effects on placental function. Conclusion: Ad.VEGF gene therapy improves fetal growth in a sheep model of FGR, although the precise mechanism of action remains unclear.
    Human Gene Therapy 03/2014; · 4.02 Impact Factor
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    ABSTRACT: Maternal uterine artery adenovirus VEGF (Ad.VEGF-A165) gene therapy has been shown to increase pre- and early postnatal growth velocity in an overnourished adolescent ovine model of fetal growth restriction. Herein our objective was to investigate the effect of prenatal Ad.VEGF on fetal and postnatal intestinal mRNA expression of angiogenic factors and their receptors (n=18 genes). In Exp. 1, first parity ewe lamb recipients were offered a control (CON; n=12) or high (H; n=45, 2 x CON) quantity of the same diet after singleton embryo transfer. At 89±1.5 d of gestation overnourished H-ewes were randomly allocated to receive 1 of 3 injections into both uterine arteries: a) Ad.VEGF-A165 (5 × 1011 particles; n=17); b) control Ad vector containing the β galactosidase reporter gene, Ad.LacZ (n=14); c) saline (n=14). CON received saline. In Exp. 2, overnourished ewes received no injection (n=6), Ad.VEGF-A165 (n=16) or saline (n=15) as described above. Ewes lambed normally at 141±0.4 d gestation and offspring were raised until weaning. Fetal (d 130) and postnatal (d 84) intestinal tissues were harvested and mRNA expression relative to 18s determined. In Exp. 1, no differences (P≥0.16) were observed in mRNA expression. In Exp. 2, maternal Ad.VEGF-A165 increased (P≤0.04) mRNA expression of FLT1, KDR, NRP1, FGF2R, TIE2, NOS3, and sGC, and tended (P≤0.10) to increase ANG1, ANG2, NRP2, FGF2, and HIF1A. Thus the previously reported benefits of this prenatal therapy on birth weight and early postnatal growth were mirrored by increased expression of a cadre of angiogenic genes. These may in turn influence intestinal vascularity and thereby absorptive capacity and nutrient uptake.
    Pediatric Research 08/2013; 74(4):480. · 2.67 Impact Factor
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    ABSTRACT: Intra-uterine growth restriction (IUGR) is involved in developmental metabolic programming and here we test the hypothesis that IUGR affects the developing hypothalamic energy balance regulatory pathways in a sex-specific manner. This experiment investigated early postnatal hypothalamic gene expression for six primary leptin- and insulin-sensitive neuropeptides and receptors in male and female IUGR (n=8 and 9, respectively) and normal (N) birth weight lambs (n=8 per gender) gestated and suckled by overnourished mothers. IUGR lambs were smaller at birth, had increased fractional growth rates (FGR), lower final body weight (11 weeks) and similar body fat content compared with N lambs, while males had higher final body weight and insulinemia but lower body fat and leptinemia than females. In situ hybridization revealed greater gene expression in the hypothalamic arcuate nucleus at 11 weeks for anorexigenic genes in females and orexigenic genes in males, with no effect of IUGR. Leptinemia correlated with gene expression for neuropeptide Y (NPY, negatively) in both sexes and pro-opiomelanocortin (POMC, positively) in females but with leptin receptor (negatively) only in males. Current FGR for girth correlated negatively with gene expression for NPY in males and POMC in females. Neither IUGR nor gender affected suckling activity (proxy for appetite) assessed at 3 weeks, but final NPY gene expression correlated with suckling weight gain in males. This study has revealed no effect of IUGR on early postnatal hypothalamic energy balance gene expression but a major effect of gender associated with major sex differences in adiposity and leptinemia.
    International journal of developmental neuroscience: the official journal of the International Society for Developmental Neuroscience 08/2013; · 2.03 Impact Factor
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    ABSTRACT: Intrauterine growth restriction is a major cause of perinatal mortality and morbidity. Injection of an adenovirus (Ad) vector containing the vascular endothelial growth factor-A165 (VEGF-A165) gene into the uterine arteries increased growth velocity and birth weight (trend) in growth restricted fetal sheep (1,2). Ad.VEGF-A165 treatment increased mRNA levels of the VEGF receptor FLT1/KDR in maternal but not fetal placental tissues and placental efficiency near term (trend) (1,2). We measured late gestation placental expression of genes regulating growth (insulin-like growth factor receptor 1, IGF-1R), lipid handling (lipoprotein lipase, LPL) and amino acid transport (TAT1) in normal and growth-restricted pregnancies with and without Ad.VEGF-A165 treatment. Single embryos (from superovulated single sire inseminated donor ewes) were transferred into adolescent recipient ewe uteri under general inhalational anaesthesia (isoflurane in O2/NO). Recipients were fed control (C n=12) or high (H n=45) intake of complete diet from 4-131 days' gestational age (dGA term=145dGA) to induce normal and restricted fetal growth, respectively (3). At 89dGA under general anaesthesia (induction with propofol IV then as above) both uterine arteries were injected with 5x1011 particles of Ad.VEGF-A165 (H-Ad.VEGF, n=18) or control vector Ad.LacZ/control saline (H-Ad.LacZ/saline, n=27; C-saline, n=12). At 131dGA ewes were killed (pentobarbitone overdose IV). RNA was extracted from separated fetal and maternal placental compartments (frozen at -80C) and real-time quantitative PCR was performed to measure mRNA levels of LPL, TAT1 and IGFR-1 (normalised to GAPDH and βactin geometric mean). Data are mean±SEM and were analysed by two-way ANOVA (placental compartment and group [C-saline; H-Ad.VEGF; H-Ad.LacZ/saline]) then Least Squares Difference correction. Regardless of placental side TAT1 and LPL mRNA levels were lower in H-Ad.VEGF compared to H-Ad.LacZ/saline (TAT1, 0.54±0.08 vs. 0.75±0.06, P=0.02; LPL, 0.77±0.09 vs. 0.97±0.07, P=0.06) and compared to C-saline (TAT1, 0.54±0.08 vs. 0.76±0.09, P=0.07; LPL, 0.77±0.09 vs. 1.03±0.10, P=0.06). Regardless of group LPL, IGFR-1 and TAT1 mRNA levels were greater in the fetal compared to maternal placental side (LPL: 1.22±0.07 vs. 0.66±0.07; IGFR-1: 1.19±0.07 vs. 0.99±0.07; TAT1: 1.24±0.07 vs. 0.13±0.06; P <0.05). These data suggest that increased fetal growth velocity following Ad.VEGF-A165 is independent of altered IGFR-1 gene expression. Decreased TAT1 and LPL gene expression following Ad.VEGF-A165 is unexpected but may reflect complex amino acid and lipid transport regulation in these animals which requires further molecular analysis. Higher expression of genes related to nutrient transfer in the fetal-facing placental portion may indicate membrane specific placental nutrient transport mechanisms.
    The Journal of Physiological Sciences 07/2013; 63(Suppl_1):773P. · 1.09 Impact Factor
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    ABSTRACT: Introduction: We previously showed that adenovirus (Ad) mediated overexpression of vascular endothelial growth factor (VEGF) in the uteroplacental circulation increases fetal growth velocity in the overnourished adolescent sheep paradigm of fetal growth restriction. Lambs born following Ad.VEGF therapy also demonstrated accelerated lean tissue accretion and enhanced insulin secretion following glucose challenge. Herein we examined for putative epigenetic changes underlying these postnatal effects by quantification of methylation at cytosine:guanine (CpG) dinucleotides. Methods: DNA was extracted from liver samples obtained at 82�0.2d postnatal age in 29 lambs born after prenatal treatment with Ad.VEGF (n = 16: 8xMale/8xFemale) or Saline (n = 13: 7xMale/6xFemale). After incubation with sodium bisulphite, PCR was performed using custom designed primers targeting 9 CpG islands across five genes: insulin, growth hormone, insulin-like growth factor (IGF)1, IGF2 and H19. Using pyrosequencing, methylation status was determined by quantifying cystosine:thymine ratios at 35 individual CpG sites. Plasma IGF1/insulin levels were measured by RIA. Results: There were no significant differences in DNA methylation between Ad.VEGF and Saline groups, except at 1 of 4 CpG dinucleotides preceding IGF2 exon-6 (3.8�0.59 vs. 1.9�0.60%, P = 0.029). Irrespective of treatment, insulin gene methylation was greater in males than females (88.7�0.23 vs. 87.0�0.50%, P = 0.007) and negatively correlated with fasting insulin levels (r = �0.431, n = 28, P = 0.022). By contrast, IGF1 methylation tended to be lower in males than females (84.3�0.16 vs. 84.8�0.22%, P = 0.053) and was unrelated to plasma IGF1 levels. Conclusion: Increased postnatal growth rates in Ad.VEGF-treated lambs most likely reflect their relative size advantage at birth rather than altered epigenetic status of key somatotropic genes.
    BJOG An International Journal of Obstetrics & Gynaecology 07/2013; 120(9):e6-e7. · 3.76 Impact Factor
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    ABSTRACT: Uterus didelphys is a rare congenital abnormality of the reproductive tract. Although it occurs in various species, there are no published reports describing pregnancy outcome in association with this abnormality. Herein we describe a case of successful unilateral singleton pregnancy in a ewe incidentally found to have uterus didelphys during the course of a biomedical research study. The pregnancy was established using assisted reproductive techniques and interrupted in late gestation, at which point the abnormality was identified. Serial ultrasound assessment of foetal biometry revealed a normal foetal growth trajectory. Despite a 45% reduction in placentome number, total placentome weight was near normal secondary to compensatory placentome growth and development. To our knowledge, this is the first detailed report of normal foetal growth in an animal with uterus didelphys and illustrates the ability of the ovine placenta to adapt to a reduced number of placentomes and maintain foetal nutrient supply.
    Reproduction in Domestic Animals 06/2013; 48(5):e78-80. · 1.39 Impact Factor
  • Reproduction Fertility and Development 05/2013; · 2.58 Impact Factor
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    ABSTRACT: Introduction: We previously showed that adenovirus (Ad) mediated over-expression of vascular endothelial growth factor (VEGF) in the uteroplacental circulation increases fetal growth velocity in the overnourished adolescent sheep paradigm of fetal growth restriction (1,2). Lambs born following Ad.VEGF therapy also demonstrated accelerated lean tissue accretion and enhanced insulin secretion following glucose challenge (3). Herein we examined for putative epigenetic changes underlying these postnatal effects by quantification of methylation at cytosine:guanine (CpG) dinucleotides. Methods: DNA was extracted from liver samples obtained at 82±0.2d postnatal age in 29 lambs born after prenatal treatment with Ad.VEGF (n=16: 8×Male/8×Female) or Saline (n=13: 7×Male/6×Female). After incubation with sodium bisulphite, PCR was performed using custom-designed primers targeting 9 CpG islands across 5 genes: insulin, growth hormone, insulin-like growth factor (IGF)1, IGF2 and H19. Using pyrosequencing, methylation status was determined by quantifying cytosine:thymine ratios at 35 individual CpG sites. Plasma IGF1/insulin levels were measured by RIA. Results: There were no significant differences in DNA methylation between Ad.VEGF and Saline groups, except at 1 of 4 CpG dinucleotides preceding IGF2 exon-6 (3.8±0.59 vs. 1.9±0.60%, p=0.029). Irrespective of treatment, insulin gene methylation was greater in males than females (88.7±0.23 vs. 87.0±0.50%, p=0.007) and negatively correlated with fasting insulin levels (r = –0.431, n=28, p=0.022). By contrast, IGF1 methylation tended to be lower in males than females (84.3±0.16 vs. 84.8±0.22%, p=0.053) and was unrelated to plasma IGF1 levels. Conclusion: Increased postnatal growth rates in Ad.VEGF-treated lambs most likely reflect their relative size advantage at birth rather than altered epigenetic status of key somatotropic genes. References 1. Carr DJ, Aitken RP, Milne JS, et al. Maternal Ad.VEGF gene therapy increases fetal growth velocity in growth restricted sheep fetuses. BJOG 2011;118:1008-1009. 2. Carr DJ, Aitken RP, Milne JS, et al. Prenatal gene therapy increases fetal growth velocity and alters uterine artery vascular reactivity in the absence of a measurable effect on uterine blood flow in a sheep model of fetal growth restriction. Archives of Disease in Childhood: Fetal and Neonatal Edition 2012;97(Suppl_1):A1. 3. Carr DJ, Aitken RP, Milne JS, et al. Alterations in postnatal growth and metabolism following prenatal treatment of intrauterine growth restriction with Ad.VEGF gene therapy in the sheep. Archives of Disease in Childhood: Fetal and Neonatal Edition 2011;96(Suppl1):Fa7.
    Archives of Disease in Childhood - Fetal and Neonatal Edition 04/2013; 98(Suppl_1):A1. · 3.45 Impact Factor
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    ABSTRACT: Introduction: We previously showed that adenovirus (Ad) mediated overexpression of vascular endothelial growth factor (VEGF) in the uteroplacental circulation increases fetal growth velocity in the over nourished adolescent sheep model of fetal growth restriction. Lambs born following Ad.VEGF therapy also demonstrated accelerated lean tissue accretion and enhanced insulin secretion after glucose challenge. Herein we examined for putative epigenetic changes underlying these postnatal effects by quantification of methylation at cytosine:guanine (CpG) dinucleotides. Methods: DNA was extracted from liver samples obtained at 82±0.2d postnatal age in 29 lambs born after prenatal treatment with Ad.VEGF (n=16: 8 male, 8 female) or Saline (n=13: 7 male, 6 female). After incubation with sodium bisulphite, PCR was performed using custom-designed primers targeting 14 CpG islands in 5 genes: insulin, growth hormone, insulin-like growth factor (IGF)1, IGF2 and H19. Using pyrosequencing, % methylation was determined by quantifying cystosine:thymine ratios at 29 individual CpG sites. Plasma IGF1/insulin levels were measured by RIA. Results: The table shows mean DNA methylation for each gene of interest. There were no significant differences between Ad.VEGF and Saline groups, except at 1 of 4 CpG dinucleotides preceding IGF2 exon 6 (3.8±0.59 vs. 1.9±0.60%, p=0.029). Irrespective of treatment, insulin gene methylation was greater in males than females (88.7±0.23 vs. 87.0±0.50%, p=0.007) and negatively correlated with fasting insulin levels (r=-0.431, n=28, p=0.022). By contrast, IGF1 methylation tended to be lower in males than females (84.3±0.16 vs. 84.8±0.22%, p=0.053) and was unrelated to plasma IGF1 levels. Saline (n=13) versus Ad.VEGF (n=16): GH: 64.8±1.90% vs. 61.9±1.28% (p=0.209) IGF1: 84.6±0.28% vs. 84.5±0.14% (p=0.564) IGF2: 20.9±0.51% vs. 20.4±0.45% (p=0.475) H19: 40.2±0.66% vs. 39.8±0.41% (p=0.536) Insulin: 88.3±0.43% vs. 87.6±0.42% (p=0.312) Conclusion: Increased postnatal growth rates in Ad.VEGF-treated lambs most likely reflect their relative size advantage at birth rather than altered epigenetic status of key somatotropic genes.
    Reproductive Sciences 03/2013; 20(3):211A. · 2.06 Impact Factor
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    ABSTRACT: Background: Fetal growth restriction (FGR) is an important obstetric condition that is commonly associated with reduced uterine blood flow. In normal sheep pregnancies, adenovirus (Ad) mediated overexpression of vascular endothelial growth factor (VEGF) in the uterine arteries increases uterine blood flow. We hypothesised that enhancing uterine blood flow would improve fetal substrate delivery in a sheep model of FGR that is characterised by reduced uterine blood flow from mid-gestation. Methods: Singleton pregnancies were established with embryo transfer in 90 adolescent ewes subsequently overnourished to generate FGR (n=78) or control fed (n=12). In study 1, at a mean gestational age of 89 days (SE 0·2), 45 overnourished ewes were randomised to receive Ad-VEGF (n=18), Ad-LacZ (control vector, n=14), or saline (n=13) injected into each uterine artery. Control-fed ewes (n=12) received saline. Uterine blood flow was monitored with indwelling flowprobes until necropsy at 131 days’ gestation (0·6). Placental mRNA expression of VEGF and its receptors, Flt1/KDR, was assessed in the maternal and fetal placental compartments by quantitative reverse transcription PCR. In study 2, at 88 days’ gestation (0·7), 33 overnourished ewes received Ad-VEGF (n=17) or saline (n=16) and were allowed to deliver spontaneously at 141 days’ gestation (0·4). In both studies fetal growth and wellbeing were evaluated (blind) using serial ultrasound. Findings: In both studies ultrasound measurements of abdominal circumference (AC) were greater in Ad-VEGF-treated FGR fetuses than in control-treated FGR fetuses at 21 days (0·3) and 28 days (0·5) post injection (p<0·001—0·047). In study 1, fewer fetuses were markedly growth-restricted (weight >2 SD below control mean) in Ad-VEGF compared with Ad-LacZ plus saline groups (5/18 vs 18/27, p=0·038). Indices of head sparing (ultrasound biparietal diameter:AC ratios, relative brain weight, and brain:liver weight ratios) were lower (p=0·001—0·046) and maternal placental Flt1/KDR mRNA expression higher (p=0·028/0·034) in Ad-VEGF than in Ad-LacZ plus saline groups, but no measurable differences in uterine blood flow were detected. In study 2, Ad-VEGF-treated lambs tended to be heavier (p=0·081) with increased placental efficiency (p=0·074). There were no maternal or fetal complications or significant differences in the level of neonatal care required to ensure lamb survival. Interpretation: Ad-VEGF safely increases fetal growth in this ovine model of FGR. Funding: Wellbeing of Women.
    The Lancet 02/2013; 381:S28. · 39.21 Impact Factor
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    ABSTRACT: Adenovirus VEGF (Ad.VEGF) gene therapy has been shown to increase pre- and early post-natal growth velocity in an ovine model of fetal growth restriction. Our objectives were to investigate the effects of Ad.VEGF on fetal visceral tissues and crypt cell proliferation at d 130 of gestation in this paradigm. First parity ewe lamb recipients were initially allocated to a control (CON; n = 12) or high (H; n = 45) quantity of the same diet at singleton embryo transfer. Control diets provided met requirements for specific age and stage of gestation and H ewes received approximately twice the dietary intake of CON. At 89 ± 1.5 d of gestation H ewes were randomly allocated to receive 1 of 3 injections into both uterine arteries: a) Ad.VEGF (5 × 1011 particles) gene; (n = 18), b) control Ad containing the β-galactosidase reporter gene, Ad.LacZ, same dose; (n = 14), and c) saline (n = 13). On d 130 of gestation ewes and fetuses were necropsied. Fetal visceral tissues were harvested, weighed, and perfusion fixed. At necropsy, H ewes had increased (P ≤ 0.001) BW, condition, and perirenal fat compared with CON (81.0 vs. 65.7 ± 1.2 kg; 2.9 vs. 2.4 ± 0.03; 1,334 vs. 543 ± 91 g, respectively). Maternal measurements were not altered by any injection treatment. Fetal BW was lower (P < 0.001) in H compared with CON (4,186 vs. 5,084 ± 214 g). Total fetal stomach,small intestine, and large intestine weights tended (P ≤ 0.07) to be lower in H compared with CON. Fetal liver weight was less (P ≤ 0.01) in H compared with CON. Fetal stomach (g/kg BW) was greater (P < 0.01) in H compared with CON. Fetal small intestine (g/kg BW) was less (P = 0.016) in Ad.VEGF vs. Ad.LacZ + saline. Small intestinal crypt cell proliferation was not altered by maternal nutrition or adenovirus-VEGF gene therapy. Adenovirus-VEGF gene therapy, while having some effects on proportional fetal visceral tissue mass, does not appear to alter intestinal crypt cell proliferation at d 130 of gestation. However, intestinal vascular responses to gene therapy treatment are unknown at this time.
    Journal of Animal Science 07/2012; 90(3/J):623. · 2.09 Impact Factor
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    ABSTRACT: Obesity disrupts homeostatic energy balance circuits leading to insulin resistance. Here we examined in vivo peripheral and central insulin sensitivity, and whether central insensitivity in terms of the voluntary food intake (VFI) response occurs within the hypothalamus or at blood-brain transfer level, during obesity and after subsequent weight loss. Sheep with intracerebroventricular (i.c.v.) cannulae were fed complete diet for 40 wk ad libitum (obese group) or at control level (controls). Thereafter, obese sheep were food restricted (slimmers) and controls fed ad libitum (fatteners) for 16 wk. Dual-energy x-ray absorptiometry (DEXA) measured total body fat, insulin analyses in blood and cerebrospinal fluid (CSF) assessed blood-brain transfer, i.v. glucose tolerance test (GTT) and insulin tolerance test (ITT) measured peripheral insulin sensitivity, and VFI responses to icv insulin assessed intrahypothalamic sensitivity. Insulinemia was higher in obese than controls; plasma insulin correlated with DEXA body fat and CSF insulin. Insulinemia was higher in fatteners than slimmers but ratio of CSF to plasma insulin correlated only in fatteners. Plasma glucose baseline and area under the curve were higher during GTT and ITT in obese than controls and during ITT in fatteners than slimmers. GTT and ITT glucose area under the curve correlated with DEXA body fat. VFI decreased after i.c.v. insulin, with response magnitude correlating negatively with DEXA body fat. Overall, insulin resistance developed first in the periphery and then within the brain, thereafter correlating with adiposity; central resistance in terms of VFI response resulted from intrahypothalamic insensitivity rather than impaired blood-brain transfer; modest weight loss improved peripheral but not central insulin sensitivity and induced central hypoinsulinemia.
    Endocrinology 05/2012; 153(7):3147-57. · 4.72 Impact Factor
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    ABSTRACT: The purpose of this study was to evaluate ultrasonographically fetal growth trajectories, placental biometry, and umbilical artery (UA) Doppler indices in growth-restricted pregnancies of overnourished adolescent ewes and normally developing pregnancies of control-fed ewes. Singleton pregnancies were established using embryo transfer in 42 adolescent ewes that were overnourished (n = 27) or control-fed (n = 15) and were scanned at weekly intervals from 83-126 days' gestation and necropsied at 131 days' gestation (term = 145 days). Ultrasonographic placental measurements were reduced and UA Doppler indices were increased from 83 days' gestation; measurements of fetal abdominal circumference and femur length, renal volume and tibia length, and biparietal diameter were reduced from 98, 105, and 112 days' gestation, respectively, in overnourished vs control-intake pregnancies. Overnourishment of adolescent sheep dams produced late-onset asymmetric fetal growth restriction that was commensurate with brain sparing. Ultrasonographic placental biometry was already reduced and UA Doppler indices increased by mid gestation in overnourished pregnancies, preceding reduced fetal growth velocity and indicating an early nutritionally mediated insult on placental development.
    American Journal of Obstetrics and Gynecology 05/2012; 207(2):141.e6-15. · 3.88 Impact Factor
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    ABSTRACT: Introduction: Adenovirus (Ad) mediated over-expression of vascular endothelial growth factor (VEGF) in the uterine artery (UtA) enhances pre- and postnatal growth in growth-restricted sheep fetuses (Carr 2011a/2011b). Herein effects on uterine blood fl ow (UBF), vascular reactivity and UtA remodelling were investigated. Methods: Singleton pregnancies were established by embryo transfer in 57 adolescent ewes subsequently overnourished to restrict placental/fetal growth or fed a control diet. At 89±1.5d gestation, overnourished ewes were randomised to receive Ad.VEGF-A165 (n=18), Ad.LacZ (n=14) or saline (n=13) injected into each UtA. Controls received saline (n=12). Flow probes were fitted around the UtA supplying the gravid horn. Fetal biometry/wellbeing was assessed blind by weekly ultrasound. UBF was monitored until necropsy at 131±1.6d. In 24 animals, three branches of UtA from both the gravid and non-gravid horns were challenged in an organ bath with phenylephrine and bradykinin to assess vessel contractility and relaxation, respectively. Adventitial vessels were immunostained with anti-vWF and counted. Intima:media ratios (IMR) were also calculated. Results: Fetal abdominal circumference measurements were greater in Ad.VEGF-A165 versus Ad.LacZ/saline groups at 112±0.1d and 119±0.1d gestation (p=<0.001–0.047) but Ad.VEGF-A165 had no measurable effect on UBF or UtA adventitial vessel number. IMR was greater in Ad.VEGF-A165 versus Ad.LacZ+saline groups in the main gravid UtA branch (p=0.016). Bradykinin-induced relaxation was increased in Ad.VEGF-A165 versus Ad.LacZ/saline/control groups in the second gravid UtA branch (p=0.001–0.032). Conclusion: Ad.VEGF-A165 increased fetal growth velocity without apparent changes in UBF. There was evidence of enhanced vasodilatation and increased IMR but no neovascularisation in UtAs treated with Ad.VEGF-A165. REFERENCES 1. Carr DJ, Aitken RP, Milne JS, Peebles DM, Martin J, Zachary I, Wallace JM, David AL. Maternal delivery of Ad.VEGF gene therapy increases fetal growth velocity in an ovine paradigm of fetal growth restriction. Reproductive Sciences 2011;18(3):269A-270A. 2. Carr DJ, Aitken RP, Milne JS, Peebles DM, Martin JF, Zachary IC, David AL, Wallace JM. Alterations in postnatal growth and metabolism following prenatal treatment of intrauterine growth restriction with Ad.VEGF gene therapy in the sheep. Archives of Disease in Childhood: Fetal and Neonatal Edition 2011;96(S1):Fa7.
    Archives of Disease in Childhood - Fetal and Neonatal Edition 04/2012; 97(Suppl_1):A1. · 3.45 Impact Factor
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    ABSTRACT: Background / Purpose: Early-onset severe fetal growth restriction (FGR) is a major cause of perinatal morbidity and mortality and is commonly associated with reduced uterine blood flow (UBF). Local uterine artery delivery of adenovirus (Ad) vascular endothelial growth factor (VEGF) gene therapy increases UBF during normal sheep pregnancy (1,2).We aimed to determine the effects of Ad.VEGF on UBF, ultrasonographic fetal growth velocity, body composition and organ morphology, and placental mRNA expression of VEGF receptors in a sheep paradigm of FGR characterised by attenuated UBF: the overnourished adolescent ewe (3). Main conclusion: Ultrasound measurements of fetal abdominal circumference, a marker of fetal growth, were significantly increased in Ad.VEGF-treated versus untreated FGR pregnancies at 3 and 4 weeks post administration of gene therapy or control treatment in mid-gestation. In late gestation mRNA expression of VEGF receptors Flt1 and KDR in the maternal placental compartment was significantly increased in Ad.VEGF-treated versus untreated FGR pregnancies.
    Reproductive Sciences 03/2012; 19(3):78A. · 2.06 Impact Factor
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    ABSTRACT: When pregnant adolescent sheep are overnourished during pregnancy normal nutrient partitioning priorities to the gravid uterus are altered, leading to impaired placental development and fetal growth restriction. We hypothesized that decreasing dietary intake in overnourished dams during the final third of gestation may reverse this inappropriate nutrient partitioning in favor of the fetus. Adolescent ewes were offered control (C; n = 12) or high (H; n = 20) dietary intakes to induce normal vs. compromised placental development. Ten ewes receiving the H intake were switched to a low intake at d90 of gestation (HL). Between d90 to 130, HL dams lost weight and adiposity, and metabolic hormones and glucose at d130 were less than H and similar to C. In spite of these maternal changes, at d130 fetal bodyweight was equivalent in HL and H groups and ∼20% less than in C. A greater degree of brain sparing was evident in HL fetuses and glucose and insulin concentrations were more perturbed than in H fetuses. Relative to C, placentome weight was reduced by 46 and 32% in H and HL and the fetal:placentome weight ratio was H > HL > C. Placental vascular morphology was largely unaffected by maternal diet during late gestation but mRNA expression of five angiogenic genes was up-regulated in the fetal cotyledon of HL pregnancies, commensurate with blood vessel remodeling. Nevertheless, overfeeding to promote maternal anabolic growth during adolescent pregnancy impairs feto-placental development that cannot be rescued by reducing maternal intake during the final third of gestation.
    Placenta 12/2011; 33(2):114-21. · 3.12 Impact Factor
  • Human Gene Therapy 10/2011; 22(10):A128. · 4.02 Impact Factor
  • Ultrasound in Obstetrics and Gynecology 09/2011; 38(S1):23 - 23. · 3.56 Impact Factor
  • Ultrasound in Medicine & Biology 08/2011; 37(8):S28-S29. · 2.46 Impact Factor

Publication Stats

413 Citations
202.81 Total Impact Points

Institutions

  • 2009–2014
    • University of Aberdeen
      • Rowett Institute of Nutrition and Health
      Aberdeen, Scotland, United Kingdom
  • 2005–2011
    • North Dakota State University
      • Department of Animal Sciences
      Fargo, ND, United States
  • 2007
    • University of Nottingham
      • School of Veterinary Medicine and Science
      Nottingham, ENG, United Kingdom