Maternal and environmental influences on thermoregulation in the neonate

Symonds, ME; Lomax, M.A.

doi:10.1079/pns19920026

Cited by 82 publications

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“…There are considerable differences in UCP1 both within different large-mammal species (7) and between small and large mammals (8) . For example, brown fat is not present in the newborn pig, which is dependent on shivering thermogenesis in order to maintain body temperature after birth (9) .…”

Section: Adipocyte Regulation In Early Lifementioning

confidence: 99%

Session on ‘Obesity’ Adipose tissue development, nutrition in early life and its impact on later obesity

et al. 2009

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It is now apparent that one key factor determining the current obesity epidemic within the developed world is the extent to which adipose tissue growth and function can be reset in early life. Adipose tissue can be either brown or white, with brown fat being characterised as possessing a unique uncoupling protein (uncoupling protein 1) that enables the rapid generation of heat by non-shivering thermogenesis. In large mammals this function is recruited at approximately the time of birth, after which brown fat is lost, not normally reappearing again throughout the life cycle. The origin and developmental regulation of brown fat in large mammals is therefore very different from that of small mammals in which brown fat is retained throughout the life cycle and may have the same origin as muscle cells. In contrast, white adipose tissue increases in mass after birth, paralleled by a rise in glucocorticoid action and macrophage accumulation. This process can be reset by changes in the maternal nutritional environment, with the magnitude of response being further determined by the timing at which such a challenge is imposed. Importantly, the long-term response within white adipocytes can occur in the absence of any change in total fat mass. The present review therefore emphasises the need to further understand the developmental regulation of the function of fat through the life cycle in order to optimise appropriate and sustainable intervention strategies necessary not only to prevent obesity in the first place but also to reverse excess fat mass in obese individuals. Pregnancy: Growth: Metabolism: Uncoupling proteinsObesity is of immense importance, affecting almost all organ systems, and is a risk factor for hypertension, type 2 diabetes, cardiovascular mortality and renal disease. Ultimately, obesity is associated with an increased relative risk of mortality (1) . Whilst not all obese adults were overweight children, being overweight in childhood is a good predictor of excess fat mass as an adult (2) . Indeed, recent data have demonstrated a 16-fold increase in the prevalence of the metabolic syndrome in overweight adolescents compared with their normal-weight peers (3) . Furthermore, the adverse effects of early obesity appear to be exacerbated in those individuals previously exposed to a suboptimal nutritional environment in utero (4) . The understanding of the impact of early-life events on later susceptibility to obesity needs to include the pronounced changes in adipocyte lineage that commence in utero at critical stages of development. This information needs to be combined with a full appreciation of the substantial differences between the species used in animal investigations of obesity, to inform knowledge not only of fat distribution but also of how the interaction between diet and energy status can vary. Adipocyte regulation in early lifeThere are at least two key factors in early life that are critical in determining adipose tissue function in the Abbreviations: PRDM, PR-domain-containing; TLR4, toll-like ...

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Section: Adipocyte Regulation In Early Lifementioning

confidence: 99%

Session on ‘Obesity’ Adipose tissue development, nutrition in early life and its impact on later obesity

et al. 2009

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“…This is a remarkable characteristic given that BAT only accounts for about 2% of the animal's weight at birth (Symonds and Lomax 1992). Unfortunately, the ability of BAT to quickly generate heat deteriorates rapidly during the first weeks following parturition (Symonds and Lomax 1992). After 3 weeks of age, BAT begins to adopt WAT characteristics and is indistinguishable from white adipose tissue (WAT) by 1 month of age (Casteilla et al 1989).…”

Section: ____________mentioning

confidence: 99%

Section: ____________mentioning

confidence: 99%

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A Novel Role for Arginine in Enhancing Neonatal Thermogenesis.

Greff

Satterfield

2011

Biology of Reproduction

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Maintenance of body temperature is one of the first and most important physiological processes that must be initiated after birth.Failure to sustain homeothermy leads to hypothermia and death. Indeed, in sheep, 40% of non-predator lamb deaths are attributed to cold and cold-related causes. Brown adipose tissue (BAT)is an essential mediator of thermogenesis in many species and is responsible for 50% of the heat generated in the newborn lamb despite comprising only 2% of body weight.Previously, we found that maternal arginine supplementation increased fetal peri-renal BAT by 62%. This observation led us to test the hypothesis that increased the amount of fetal BAT will enhance neonatal thermogenesis at birth and thus combat the effects of cold stress. Thirty-one multiparous Suffolk ewes gestating singletons and twins were assigned to receive either intravenous injections of L-arginine (27 mg/kg bodyweight; n=17) or sterile saline (n=14)

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“…primarily dependent on shivering thermogenesis in muscle in order to prevent hypothermia at birth (Symonds & Lomax 1992). This due to an open reading frame on the BAT-specific uncoupling protein 1 (UCP1) gene in the porcine species meaning that UCP1 is not expressed (Berg et al 2006).…”

Section: Thematic Researchmentioning

confidence: 99%

UCP1 is present in porcine adipose tissue and is responsive to postnatal leptin

Mostyn¹,

Attig²,

Larcher³

et al. 2014

Journal of Endocrinology

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Intrauterine growth restriction (IUGR) may be accompanied by inadequate thermoregulation, especially in piglets that are not considered to possess any brown adipose tissue (BAT) and are thus entirely dependent on shivering thermogenesis in order to maintain body temperature after birth. Leptin can stimulate heat production by promoting non-shivering thermogenesis in BAT, but whether this response occurs in piglets is unknown. Newborn female piglets that were characterised as showing IUGR (mean birth weight of approximately 0.98 kg) were therefore administered injections of either saline or leptin once a day for the first 5 days of neonatal life. The dose of leptin was 0.5 mg/kg, which is sufficient to increase plasma leptin by approximately tenfold and on the day of birth induced a rapid increase in body temperature to values similar to those of normal-sized 'control' piglets (mean birth weight of w1.47 kg). Perirenal adipose tissue was then sampled from all offspring at 21 days of age and the presence of the BAT-specific uncoupling protein 1 (UCP1) was determined by immunohistochemistry and immunoblotting. UCP1 was clearly detectable in all samples analysed and its abundance was significantly reduced in the IUGR piglets that had received saline compared with controls, but was raised to the same amount as in controls in those IUGR females given leptin. There were no differences in gene expression between primary markers of brown and white adipose tissues between groups. In conclusion, piglets possess BAT that when stimulated exogenously by leptin can promote increased body temperature. IntroductionBrown adipose tissue (BAT) is essential for effective adaptation to cold exposure of the extra-uterine environment in precocial species such as sheep in which there is rapid activation of BAT around the time of birth (Clarke et al. 1997). In pigs, however, it has long been considered that BAT is not present (Trayhurn et al. 1989) and the newborn is Journal of Endocrinology Thematic ResearchA MOSTYN and others UCP1 and leptin in porcine 223:1 M31-M38http://joe.endocrinology-journals.org Ñ 2014 Society for Endocrinology DOI: 10.1530/JOE-14-0155Printed in Great BritainPublished by Bioscientifica Ltd.primarily dependent on shivering thermogenesis in muscle in order to prevent hypothermia at birth (Symonds & Lomax 1992). This due to an open reading frame on the BAT-specific uncoupling protein 1 (UCP1) gene in the porcine species meaning that UCP1 is not expressed (Berg et al. 2006). However, it has more recently been suggested that BAT is present in young piglets because of the different morphological appearances of adipocytes within perirenal adipose tissue in 2-week-old females (Attig et al. 2008). However, this remains to be confirmed by direct measurements of UCP1. Moreover, our understanding of BAT has now been transformed as a consequence of the discovery of beige adipocytes that express UCP1 at approximately 10% of the amount observed in classical BAT , Wu et al. 2013, but whether comparable depots are be pr...

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Maternal and environmental influences on thermoregulation in the neonate

Cited by 82 publications

References 50 publications

Session on ‘Obesity’ Adipose tissue development, nutrition in early life and its impact on later obesity

Session on ‘Obesity’ Adipose tissue development, nutrition in early life and its impact on later obesity

A Novel Role for Arginine in Enhancing Neonatal Thermogenesis.

UCP1 is present in porcine adipose tissue and is responsive to postnatal leptin

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