ORCID Profile
0000-0002-1281-2837
Current Organisations
The University of Auckland
,
The Liggins Institute, University of Auckland
,
Universidade Católica Portuguesa
,
Calouste Gulbenkian Foundation
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Publisher: The Endocrine Society
Date: 23-07-2015
DOI: 10.1210/EN.2015-1095
Abstract: Adults born preterm are at increased risk of impaired glucose tolerance and diabetes. Late gestation fetuses exposed to high blood glucose concentration also are at increased risk of impaired glucose tolerance as adults. Preterm babies commonly become hyperglycemic and are thus exposed to high blood glucose concentration at an equivalent stage of pancreatic maturation. It is not known whether preterm birth itself, or complications of prematurity, such as hyperglycemia, alter later pancreatic function. To distinguish these, we made singleton preterm lambs hyperglycemic (HYPER) for 12 days after birth with a dextrose infusion and compared them with vehicle-treated preterm and term controls and with HYPER lambs made normoglycemic with an insulin infusion. Preterm birth reduced β-cell mass, apparent by 4 weeks after term and persisting to adulthood (12 mo), and was associated with reduced insulin secretion at 4 months (juvenile) and reduced insulin mRNA expression in adulthood. Hyperglycemia in preterm lambs further down-regulated key pancreatic gene expression in adulthood. These findings indicate that reduced β-cell mass after preterm birth may be an important factor in increased risk of diabetes after preterm birth and may be exacerbated by postnatal hyperglycemia.
Publisher: Elsevier BV
Date: 07-2012
DOI: 10.1016/J.YHBEH.2012.06.006
Abstract: Low food availability often coincides with pregnancy in grazing animals. This study investigated how chronic reductions in food intake affected feeding motivation, and metabolic and endocrine parameters in pregnant sheep, which might be indicative of compromised welfare. Ewes with an initial Body Condition Score of 2.7±0.3 (BCS 0 indicates emaciation and 5 obesity) were fed to attain low (LBC 2.0±0.0,), medium (MBC 2.9±0.1) or high BCS (HBC 3.7±0.1) in the first trimester of pregnancy. A feeding motivation test in which sheep were required to walk a set distance for a palatable food reward was conducted in the second trimester. LBC and MBC ewes consumed more rewards (P=0.001) and displayed a higher expenditure (P=0.02) than HBC ewes, LBC ewes also tended to consume more rewards than MBC ewes (P=0.09). Plasma leptin and glucose concentrations were inversely correlated to expenditure (both P<0.05) and appear to be associated with hunger in sheep. LBC ewes were in negative energy balance, with lower muscle dimensions, plasma glucose, leptin, insulin, cortisol, and insulin-like growth factor-1 concentrations and higher free fatty acids concentrations compared to HBC ewes metabolic and endocrine parameters of the MBC ewes were intermediate. The high feeding motivation and negative energy balance of low BCS ewes suggested an increased risk of compromised welfare. Imposing even a small cost on a food reward reduced motivation substantially in high BCS ewes (despite high intake when food was freely available). Assessment of a willingness to work for rewards, combined with measures of key metabolic and endocrine parameters, may provide sensitive barometers of welfare in energetically-taxed animals.
Publisher: Routledge
Date: 29-03-2012
Publisher: Public Library of Science (PLoS)
Date: 25-05-2012
Publisher: Cambridge University Press (CUP)
Date: 20-11-2021
DOI: 10.1017/S2040174420001063
Abstract: Maternal periconceptional undernutrition (PCUN) affected fetal pancreatic maturation in late gestation lambs and impaired glucose tolerance in 10-month-old sheep. To examine the importance of the timing of maternal undernutrition around conception, a further cohort was born to PCUN ewes [undernourished for 61 d before conception (PreC), 30 d after conception (PostC), or 61 d before until 30 d after conception (PrePostC)], or normally fed ewes (Control) ( n = 15–20/group). We compared glucose tolerance, insulin secretion, and sensitivity at 36 months of age. We also examined protein expression of insulin signalling proteins in muscle from these animals and in muscle from a fetal cohort (132 d of gestation n = 7–10/group). Adult PostC and PrePostC sheep had higher glucose area under the curve than Controls ( P = 0.07 and P = 0.02, respectively), whereas PreC sheep were similar to Controls ( P = 0.97). PostC and PrePostC had reduced first-phase insulin secretion compared with Control ( P = 0.03 and P = 0.02, respectively). PreC was similar to Control ( P = 0.12). Skeletal muscle SLC2A4 protein expression in PostC and PrePostC was increased 19%–58% in fetuses ( P = 0.004), but decreased 39%–43% in adult sheep ( P = 0.003) compared with Controls. Consistent with this, protein kinase C zeta (PKC ζ) protein expression tended to be increased in fetal ( P = 0.09) and reduced in adult ( P = 0.07) offspring of all PCUN ewes compared with Controls. Maternal PCUN alters several aspects of offspring glucose homeostasis into adulthood. These findings suggest that maternal periconceptional nutrition has a lasting impact on metabolic homeostasis of the offspring.
No related grants have been discovered for Isabel Capeloa Gil.