I. The Relationship between the Blood Levels of Glucose, Lactic Acid and Pyruvic Acid in the Mother and in both Umbilical Vessels of the Healthy Fetus

Stembera, Z; Hodr, J

doi:10.1159/000240031

Cited by 44 publications

(21 citation statements)

References 7 publications

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“…There have been many studies of the transplacental concentration gradient for glucose in human pregnancies and in animal studies (1)(2)(3)(4)19). These studies have also determined the relationship between glucose delivery to the fetus and the maternal glucose concentration.…”

Section: Discussionmentioning

confidence: 99%

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Fetal and Maternal Non-glucose Carbohydrates and Polyols Concentrations in Normal Human Pregnancies at Term

Brusati

Jóźwik

et al. 2005

Pediatr Res

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The objective of the present investigation was to determine fetal and maternal plasma concentrations of nonglucose carbohydrates and polyols in normal human pregnancies at term. Uncomplicated human pregnancies (n ϭ 50) were studied at Ն37 wk gestation. Blood samples were obtained from umbilical artery, umbilical vein, and maternal peripheral blood at the time of elective cesarean section. Plasma concentrations of inositol, glycerol, erythritol, sorbitol, and mannose were determined by HPLC analysis. Differences between umbilical venous, umbilical arterial, and maternal concentration were tested by the two-tailed t test for paired samples. Correlations between umbilical and maternal concentration and between umbilical venoarterial concentration difference and umbilical arterial concentration were assessed by Pearson's correlation and multiple regression analysis. All newborns were appropriate for gestational age, and oxygenation and acid-base balance were within the normal range for all fetuses studied. For most of the polyols (inositol, sorbitol, and erythritol), the fetal concentration was significantly higher than the maternal concentration. The umbilical venoarterial concentration difference for inositol was Ϫ10.5 Ϯ 3.6 M, for glycerol was 10 Ϯ 1.7 M, for sorbitol was 3.8 Ϯ 0.5 M (p Ͻ 0.001), and for mannose was 7.6 Ϯ 0.7 M. There was a significant correlation between maternal concentration and umbilical venous concentration of mannose (UV MAN ϭ 15.38 ϩ 0.69 M MAN ; R 2 ϭ 0.46; p Ͻ 0.001). These results indicate that in normal human pregnancies at term, inositol is produced by the fetus, sorbitol is produced by the placenta, and there is a significant umbilical uptake of mannose from the maternal circulation. The transport of glucose across the human placenta has been well studied in both normal and high-risk pregnancies (1-4). However, the study of the other carbohydrates and sugar alcohols in plasma has received far less attention. In part, this may reflect the untested assumption that other carbohydrates and polyols can be produced from glucose in sufficient amounts to meet fetal requirements. One might assume, then, that there is little need for a supply of these other compounds to the fetus by placental transport. However, studies of the nutritional supply of amino acids in early development have emphasized that many amino acids that are considered "nonessential" may be required in the dietary supply to the fetus or the newborn (5,6). The same may be true of some carbohydrates. Recent studies have suggested that mammalian cells may require an exogenous supply of mannose to meet mannose 6-phosphate requirements for glycoprotein synthesis (7). Furthermore, the biologic importance of the polyols has received attention with respect to their accumulation in reproductive tissues (8 -10) and to their roles in complications of diabetes (11,12). A recent study demonstrated that a low maternal serum inositol concentration is associated with a 2.6-fold increased risk for offspring with spina bifida (13). In additio...

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Section: Discussionmentioning

confidence: 99%

“…The transport of glucose across the human placenta has been well studied in both normal and high-risk pregnancies (1)(2)(3)(4). However, the study of the other carbohydrates and sugar alcohols in plasma has received far less attention.…”

mentioning

confidence: 99%

Fetal and Maternal Non-glucose Carbohydrates and Polyols Concentrations in Normal Human Pregnancies at Term

Brusati

Jóźwik

et al. 2005

Pediatr Res

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“…That amino acids and glucose are major exogenous nutrients for the fetus is not surprising, given the net accretion of protein durReceived for publication 31 March 1981 and in revised form 23 February 1982. ing fetal growth and the apparent requirement for glucose by fetal organs, most notably brain (3). However, the physiologic significance of a large exogenous supply of lactate has received comparatively little attention (4,5).…”

Section: Introductionmentioning

confidence: 99%

Simultaneous measurements of lactate turnover rate and umbilical lactate uptake in the fetal lamb.

Sparks¹,

Hay²,

Bonds³

et al. 1982

J. Clin. Invest.

133

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A B S T R A C T Lactic acid represents a major exogenous nutrient for the developing fetal lamb in utero. Our study was undertaken (a) to quantitate the net consumption of lactate by the fetus, (b) to quantitate the net lactate production and metabolism by the placenta, and (c) to compare the net fetal lactate consumption with fetal lactate use, measured simultaneously with radioactive tracers. 14 pregnant sheep were prepared with catheters in the maternal femoral artery and uterine vein and in the fetal aorta and umbilical vein. By simultaneous application of the Fick principle to the uterine and umbilical circulations, placental glucose consumption and placental lactate production were rapid, averaging 39.8±5.1 and 11.8±0.7 mg. min-'. Net lactate umbilical uptake averaged 1.95±0.16 mg-' kg-' min-'. During infusion of L-[14C(U)]lactate, fetal lactate turnover was much more rapid, averaging 6.5±0.8 mg* kg-' * min-1, and lactate utilization within the anatomic fetus was 5.9±0.7 mg* kg-l min-'. During infusion of tracer glucose, endogenous fetal lactate production from glucose and nonglucose substrates averaged 3.0 and 1.5 mg * kg-l * min-1, respectively. The present studies have quantitated under well oxygenated, steady-state conditions, the rapid placental metabolism and production of lactate, the net fetal consumption of lactate, and the rapid endogenous fetal lactate production from glucose and nonglucose substrates.

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“…However, many experimental as well as studies in human pregnancies both in vivo (1)(2)(3) and in vitro (4,5) have shown that lactate is produced within the placenta and delivered into both the maternal and umbilical circulation where it serves as source of carbon for fetal growth. This has been clearly demonstrated by studies in pregnant sheep where fetal utilization of lactate at term is three times higher than the umbilical uptake (approximately 4 mg/kg/min) in the welloxygenated fetus (6).…”

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confidence: 99%

“…The fetal liver is the organ with the highest lactate consumption and liver lactate uptake almost equals umbilical uptake: lactate is then used for oxidation and synthesis of fatty acid and glycogen (7). In human pregnancies, fetal lactate concentration is higher than maternal (2,3). Many clinical studies at the time of delivery (i.e.…”

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confidence: 99%

Lactacidemia in Intrauterine Growth Restricted (IUGR) Pregnancies: Relationship to Clinical Severity, Oxygenation and Placental Weight

et al. 2006

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ABSTRACT:The aim of the study was to evaluate the impact of clinical severity and placental weight upon fetal lactacidemia in intrauterine growth restricted (IUGR) pregnancies. Seventy pregnancies complicated by IUGR were compared with 70 normal (appropriate for gestational age, AGA) pregnancies at the time of elective cesarean section. IUGR pregnancies were divided according to clinical severity in three groups: Group 1 had normal fetal heart rate (FHR) and normal pulsatility index of the umbilical artery (PI); Group 2 had normal FHR and abnormal PI; and Group 3 had abnormal FHR and PI. No cases with severe lactacidemia had placental weights Ն250 g. Forty-four fetuses had placental weight Ͻ250 g: Twenty-four had severe lactacidemia and all were Group 2 and 3, whereas 20 had normal umbilical artery lac (lactate) (and small placentas) regardless of the clinical severity. Gestational age, fetal and placental weights, F/P ratios, uv (umbilical vein) and ua lac and ua oxygen content and pH were significantly decreased in fetuses with small placentas and high lactate. There was a significant relationship between fetal and placental weight in AGA and IUGR. However, IUGR fetuses with placental weight Ն250 g exhibited an F/P ratio significantly lower than that in AGA fetuses suggesting that IUGR may be due to a reduction of placental function per gram of tissue. (Pediatr Res 59: 570-574, 2006) L actate represents the end product of anaerobic metabolism of glucose. However, many experimental as well as studies in human pregnancies both in vivo (1-3) and in vitro (4,5) have shown that lactate is produced within the placenta and delivered into both the maternal and umbilical circulation where it serves as source of carbon for fetal growth. This has been clearly demonstrated by studies in pregnant sheep where fetal utilization of lactate at term is three times higher than the umbilical uptake (approximately 4 mg/kg/min) in the welloxygenated fetus (6). The fetal liver is the organ with the highest lactate consumption and liver lactate uptake almost equals umbilical uptake: lactate is then used for oxidation and synthesis of fatty acid and glycogen (7). In human pregnancies, fetal lactate concentration is higher than maternal (2,3). Many clinical studies at the time of delivery (i.e. under non-steady stressed conditions) have shown that umbilical venous and arterial lactate concentrations as well as the umbilical venoarterial concentration difference correlate with Apgar scores both at 1= and 5= (8,9). In clinical studies performed at the time of spontaneous delivery, lactate concentrations have been shown to represent a much more reliable marker of fetal acidosis compared with pH measurements (10,11). However, difficulties in sample management have limited its widespread clinical application. Recently the characteristics of L-lactic acid transport across the human placental syncytiotrophoblast have been described (12,13) as has been done for human erythrocytes (14), hepatocytes (15), intestinal brush border membrane (16,17)...

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I. The Relationship between the Blood Levels of Glucose, Lactic Acid and Pyruvic Acid in the Mother and in both Umbilical Vessels of the Healthy Fetus

Cited by 44 publications

References 7 publications

Fetal and Maternal Non-glucose Carbohydrates and Polyols Concentrations in Normal Human Pregnancies at Term

Fetal and Maternal Non-glucose Carbohydrates and Polyols Concentrations in Normal Human Pregnancies at Term

Simultaneous measurements of lactate turnover rate and umbilical lactate uptake in the fetal lamb.

Lactacidemia in Intrauterine Growth Restricted (IUGR) Pregnancies: Relationship to Clinical Severity, Oxygenation and Placental Weight

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