Maternal manipulation of brown adipose tissue and liver development in the ovine fetus during late gestation

Clarke, L.; Bryant, M. J.; Lomax, M.A.; Symonds, Michael

doi:10.1079/bjn19970086

Cited by 77 publications

(70 citation statements)

References 27 publications

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“…1). This pattern contrasts with both human subjects and sheep in which UCP1 gradually increases in abundance through late gestation (15) to peak at birth (10) before declining over the first month to undetectable levels in sheep (16) , a process that takes approximately 9 months after birth in human subjects (17) . These substantial differences between species must be given full consideration when considering the translational relevance of findings from small mammals to human subjects.…”

Section: The Ontogeny Of Brown Fat Developmentcontrasting

confidence: 63%

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: The Ontogeny Of Brown Fat Developmentcontrasting

confidence: 63%

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

et al. 2009

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“…The capacity for heat production by BAT is determined by both the concentration of UCP and the activity of the proton conductance pathway by which the electron transport chain becomes uncoupled from adenosine triphosphate (ATP) synthesis. UCP is present before birth in lambs and calves but exhibits a low thermogenic activity (Casteilla, Forest, Robelin, Ricquier, Lombert & Ailand, 1987;Clarke, Bryant, Lomax & Symonds, 1997a). At birth, the newborn is subjected to a dramatic decline in environmental temperature, and this cold exposure appears to be the signal for a rapid rise in metabolic rate in conjunction with an increase in both the amount of UCP and its thermogenic activity (Clarke, Heasman, Firth & Symonds, 1997b), as well as the level of mRNA for UCP (Casteilla, Champigny, Bouilland, Robelin & Ricquier, 1989).…”

Section: Introductionmentioning

confidence: 99%

Adipose Tissue Development During Early Postnatal Life in Ewe-Reared Lambs

Clarke¹,

BUSS²,

JUNIPER³

et al. 1997

Exp. Physiol.

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SUMMARYThis study examines the precise time course that brown adipose tissue (BAT) takes to adopt the characteristics of white adipose tissue in postnatal lambs. Perirenal adipose tissue was sampled from ewe-reared lambs within 1 h of birth and at 1, 2, 4, 7, 14, 21 and 30 days of age and analysed for the amount of mRNA for uncoupling protein (UCP), the amount and activity of UCP, and protein, mitochondrial protein and lipid content. This was combined with measurements of colonic temperature and jugular venous plasma concentrations of thyroid hormones and insulinlike growth factor-I (IGF-1). Over the first 4-7 days of age, large quantities of UCP mRNA were associated with a peak in plasma triiodothyronine concentration at 2 days of age followed by a maximal amount and activity of UCP at 4 days and a basal colonic temperature of 39 3°C. Between 7 and 30 days there was a large increase in lipid deposition as the amount and activity of UCP and the amount of UCP mRNA declined to basal values and colonic temperature was maintained at 40 'C. A significant positive relationship between perirenal adipose tissue lipid content and plasma IGF-1 concentration was observed throughout the study period. It is concluded that ovine adipose tissue maturation occurs in two distinct phases over the first month of life. The precise time scale of this process could be regulated in part by the lamb's body temperature which determines whether adipose tissue is required for heat production (i.e. BAT) or as an endogenous energy source (i.e. white adipose tissue).

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“…The beneficial effects on the fetus and newborn include not only an increase in brown fat but also a larger liver with greater glycogen stores Clarke et al, 1997a). This means that newborn is better adapted not only to meet the thermal challenge of the extra-uterine environment but also to improve the thyroid and respiratory function (Symonds et al, 1993;Clarke et al, 1997a).…”

Section: The Influence Of Temperature On Fetal Developmentmentioning

confidence: 99%

Nutritional regulation of fetal growth and implications for productive life in ruminants

Symonds¹,

Sebért²,

Budge³

2010

Animal

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The maternal nutritional and metabolic environment is critical in determining not only the reproductive success but also the long-term health and viability of the offspring. Changes in maternal diet at defined stages of gestation coincident with different stages of development can have pronounced effects on organ and tissue function in later life. This includes adipose tissue for which differential effects are observed between brown and white adipose tissues. One early, critical window of organ development in the ruminant relates to the period covering uterine attachment, or implantation, and rapid placental growth. During this period, there is pronounced cell division within developing organelles in many fetal tissues, leading to their structural development. In sheep, a 50% global reduction in caloric intake over this specific period profoundly affects placental growth and morphology, resulting in reduced placentome weight. This occurs in conjunction with a lower capacity to inactivate maternal cortisol through the enzyme 11b-hydroxysteroid dehydrogenase type 2 in response to a decrease in maternal plasma cortisol in early gestation. The birth weight of the offspring is, however, unaffected by this dietary manipulation and, although they possess more fat, this adaptation does not persist into adulthood when they become equally obese as those born to control fed mothers. Subsequently, after birth, further changes in fat development occur which impact on both glucocorticoid action and inflammatory responses. These adaptations can include changes in the relative populations of both brown and white adipocytes for which prolactin acting through its receptor appears to have a prominent role. Earlier when in utero nutrient restricted (i.e. between earlyto-mid gestation) offspring are exposed to an obesogenic postnatal environment; they exhibit an exaggerated insulin response, which is accompanied by a range of amplified and thus, adverse, physiological or metabolic responses to obesity. These types of adaptations are in marked contrast to the effect of late gestational nutrient restriction, which results in reduced fat mass at birth. As young adults, however, fat mass is increased and, although basal insulin is unaffected, these offspring are insulin resistant. In conclusion, changes in nutrient supply to either the mother and/or her fetus can have profound effects on a range of metabolically important tissues. These have the potential to either exacerbate, or protect from, the adverse effects of later obesity and accompanying complications in the resulting offspring.

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Maternal manipulation of brown adipose tissue and liver development in the ovine fetus during late gestation

Cited by 77 publications

References 27 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

Adipose Tissue Development During Early Postnatal Life in Ewe-Reared Lambs

Nutritional regulation of fetal growth and implications for productive life in ruminants

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