Measurement of Placental Blood Flow in the Pig and Its Relation to Placental and Fetal Weight

Wootton, R; McFadyen, I.; Cooper, JE

doi:10.1159/000240984

Cited by 63 publications

(40 citation statements)

References 6 publications

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“…The results support the idea that fetal growth is largely dependent on the availability of nutrients and oxygen determined by the rate of placental blood flow (3,12). The smaller placental size, which in the small fetuses is proportional to the fetal growth retardation, is probably also determined by the reduced placental blood flow.…”

Section: Discussionsupporting

confidence: 82%

Placental Blood Flow and Transfer of Nutrient Analogs in Large, Average, and Small Guinea Pig Littermates

Saintonge

Rosso

1981

Pediatr Res

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Pediatr. SummaryPlacental blood flow in the maternal side and transfer of ["CIa-amino isobutyric acid (AIB) and lSHlmethylglucose (MG) were measured in 22 pregnant guinea pigs at various gestational ages. The fetuses were divided in three groups according to their body weights: small, average, and large. Body weight was 85.25% of average values in the small fetuses and 114.12% in the large fetuses. Placental weight was 121.73% of average in the large fetuses and 84.42% in the small fetuses. Placental blood flow was 134.48% of average in large fetuses and 73.18% in small fetuses. AIB and MC transfers were significantly lower in the small fetuses (80.33% and 86.06%, respectively, of average values). In contrast, in large fetuses, AIB transfer was 123.4356, and MC transfer was 113.96% of average. Significant correlations were found between fetal and placental weight and placental blood flow and transfer of AIB and MG in the various groups. Placental transfer of AIB and placental blood flow were significantly correlated in the small ( r = 0.59) and average weight fetuses ( r = 0.37). In addition, the slope of the regression cuwe for AIB was significantly steeper in the small fetuses when compared with the slope of average and large fetuses. Placental blood flow and transfer of MG were significantly correlated only in the large fetuses ( r = 0.48). In the small fetuses, the rate of AIB transfer was proportionally more reduced than that of MG transfer as the rate of placental blood flow decreased.The results demonstrate that spontmeous fetal growth retardation in the guinea pig is associated with a smaller placenta, a reduced placental blood flow, and a reduced transfer of AIB and MG. Inasmuch as in the small fetuses AIB transfer was proportionally more reduced than MG transfer, it is suggested that in addition to the reduced blood flow lMted availabwty of certain essential amino acids may be a cause of fetal growth retardation. SpeculationA reduced placental transfer of certain essential amino acids may further aggravate the fetal growth retardation associated with low placental blood flow.Fetal growth is influenced by the interaction of intrinsic or genetic factors and extrinsic factors imposed by the intrauterine environment. In turn, the intrauterine environment is influenced by such maternal factors as size, parity, smoking, and nutritional status (4). The mechanisms by which these maternal factors influence fetal growth remain unknown.In polytocous animals such as the mouse, the rat, and the guinea pig, the rate of placental blood flow is believed to be the major determinant of fetal growth. For instance, the inverse correlation between mean fetal weight and the number of fetuses in one uterine horn has been attributed to reduced placental blood perfusion (8). Similarly, the smaller size of the fetuses in certain positions within the uterine horns also has been attributed to hemodynamic factors (8). The relation of fetal growth to uterine blood flow is further supported by experiments demonstrating that a chr...

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Section: Discussionsupporting

confidence: 82%

Placental Blood Flow and Transfer of Nutrient Analogs in Large, Average, and Small Guinea Pig Littermates

Saintonge

Rosso

1981

Pediatr Res

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“…Conditions associated with reduced rate of fetal growth (e.g. maternal genotype, increased numbers of fetuses, maternal nutrient deprivation, environmental heat stress) are also associated with reduced rates of placental blood flow and fetal oxygen and nutrient uptakes (Wootton et al, 1977;Morriss et al, 1980;Reynolds et al, 1985a, b;. Reduced rate of fetal growth can lead to decreased birth weight, which has a major impact on neonatal survival and growth (Record et al, 1952;Anderson et al, 1978;Fahmy et al, 1978;Huffman et al, 1985).…”

Section: Introductionmentioning

confidence: 99%

Secretion of angiogenic activity by placental tissues of cows at several stages of gestation

Reynolds

Redmer²

1988

Reproduction

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“…We have demonstrated that placentas supplying the smallest fetus in the uterus are disproportionally lighter than those supplying average-sized fetuses in the same litter (Ashworth et al 2001). These data, combined with the positive relationship between placental blood flow and fetal weight in the pig (Wootton et al 1977), imply that there is a generalised reduction in the ability of placentas supplying small fetuses to deliver nutrients. In addition, there is increasing evidence in a variety of species, including rat, guinea pig, sheep and human, of an association between placental amino acid transport and fetal growth (reviewed in Sibley et al 1997).…”

Section: Introductionmentioning

confidence: 90%

Placental transport of leucine in a porcine model of low birth weight

Finch¹,

Yang²,

Nwagwu³

et al. 2004

Reproduction

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Low birth weight is a major factor in neonatal morbidity and mortality in humans and domestic species and is a predictor of physiological disorders in adulthood. This study utilised the naturally occurring variation in pig fetal size within a uterus to test the hypothesis that placental amino acid transport capability is associated with fetal growth. Leucine uptake by trophoblast vesicles prepared from placentas supplying an average-sized fetus and the smallest fetus in the uterus was assessed. On days 45 and 65 of gestation, uptake of leucine by the porcine placenta was predominantly sodium independent and was inhibited by the non-metabolised leucine analogue 2-amino-2-norbornane-carboxylic acid, indicating that uptake occurs via system L. By day 100 the uptake of leucine by placentas supplying average-sized fetuses had changed from being predominantly sodium independent to involving both sodium-dependent (system B 0 ) and -independent (system L) pathways. This change was not seen in placentas supplying the smallest fetus, which continued to display predominantly sodium-independent uptake.In conclusion, these data show gestational-and fetal size-dependent changes in the transport of leucine across the porcine placenta.

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Measurement of Placental Blood Flow in the Pig and Its Relation to Placental and Fetal Weight

Cited by 63 publications

References 6 publications

Placental Blood Flow and Transfer of Nutrient Analogs in Large, Average, and Small Guinea Pig Littermates

Placental Blood Flow and Transfer of Nutrient Analogs in Large, Average, and Small Guinea Pig Littermates

Secretion of angiogenic activity by placental tissues of cows at several stages of gestation

Placental transport of leucine in a porcine model of low birth weight

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