Metabolic Changes in Human Placental Tissue in Diabetes Mellitus

Diamant, Yoram Z.; Kissilevitz, Rita

doi:10.1007/978-1-4684-1191-1_17

Cited by 7 publications

(7 citation statements)

References 31 publications

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“…4). These findings agree with the enhanced glycogen and lipid deposition found in placentas from diabetic mothers (26,27). The very high G/Oz quotients measured under conditions of marked hyperglycemia ( Table 2) also suggest that the maximal capacity of the placenta to oxidize glucose becomes rapidly saturated, as does total lactate production when maternal glucose concentration increases.…”

Section: Discussionsupporting

confidence: 80%

Glucose Uptake, Utilization, and Transfer by the Human Placenta as Functions of Maternal Glucose Concentration

1986

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ABSTRACT. The impact of varying maternal glucose concentrations on glucose uptake, transfer, and metabolism was investigated in the human placenta perfused in vitro. The rates of placental glucose uptake from the maternal perfusate and transfer to the fetal perfusate were significantly correlated with maternal glucose concentration up to 20 mM. Placental glucose utilization was also dependent upon maternal glucose concentration up to 17 mM. Between 3 and 53 mM maternal glucose, lactate production increased 3-fold while no change in oxygen consumption could be demonstrated. Correlatively, glucose storage was shown to increase dramatically above 10 mM maternal glucose. These results suggest that glucose supply to the fetus may be limited in times of maternal hypoglycemia and that placental mechanism(s) may serve to buffer glucose transfer to the fetus in conditions of hyperglycemia. Chronic changes in maternal glycemia (hypo or hyper) are known to alter fetal growth and development (1, 2). In the human, the contribution of the placenta to these perturbations is not fully understood. Although placental utilization and transfer of glucose have been studied for many years (3), data are still scarce. This is mainly due to the fact that the studies have been performed in vitro using different experimental procedures, such as placental tissue slices (4, 5), isolated microvilli (6, 7), or perfused placenta (8, 9). In some of these studies, metabolic characteristics were poorly controlled and the results displayed considerable variability. So far, most of the data concerning placental metabolism has been obtained from studies performed in vivo in the sheep (1 0-12). However, it is difficult to extrapolate the data collected in ruminant epitheliochorial placenta to the hemochorial human placenta. The present study was undertaken to determine whether changes in maternal glucose concentration could modify placental glucose metabolism and to what extent this could affect glucose supply to the fetus. MATERIALS AND METHODSPerfusion technique. Term human placentas were obtained from uncomplicated pregnancies after either vaginal delivery or caesarean section. The perfusion experiments were performed on an isolated lobule according to the method described by Panigel et al. (Sigma, St Louis, MO) concentration in medium perfusing the fetal side was fixed at 2.8 mM. Glucose concentration in medium perfusing the maternal side varied from 2.8 to 53 mM. In some experiments 3-3H-~-glucose (10 mCi/mmol, NEN, Paris, France) was added to arterial maternal perfusate to determine the diffusion rate of glucose.Arterial perfusion fluids were continuously gassed with 95%O2 + 5% C02. Flow rates were monitored with R2 15 A Brooks flowmeters and pressures were measured with mercury manometers (Boulitte, Paris, France) on fetal and maternal circulations. Experimental protocol and sampling procedures. Within 30min after delivery the main fetal artery and vein draining the selected lobule were cannulated. The experiments started 20 min after the onse...

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Section: Discussionsupporting

confidence: 80%

Glucose Uptake, Utilization, and Transfer by the Human Placenta as Functions of Maternal Glucose Concentration

1986

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“…Elevated levels of triglyceride. cholesterol, and phospholipid observed in placental tissue and the fetal circulation of GDM pregnancies suggest that alterations in placental metabolism and transfer might be factors in the development offetal macrosomia [184]; however, significant correlations have been reported between birth weight in GDM pregnancies and maternal plasma levels of glucose, amino acids, fatty acids, and triglycerides [185]. The distribution of maternal nutrient fuels is insulin-dependent; the development of fetal pancreatic tl-cells is quite sensitive and may be enhanced in GDM by minimal elevations in blood glucose and minor alterations in other nutrient fuels.…”

Section: Fetal Growth Dysfunctionmentioning

confidence: 96%

The role of the placenta in fetal nutrition and growth.

Garnica

Chan

1996

Journal of the American College of Nutrition

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The placenta plays a key role in the nutrition of the fetus. It mediates the active transport of nutrients and metabolic wastes across the barrier separating maternal and fetal compartments, as well as modifying the composition of some nutrients through its own metabolic activity. The function of the placenta is essential to the growth of a healthy fetus; it is becoming apparent that the activities of the placenta are in turn modulated by signals originating from the fetus. Communication between placenta and fetus is especially critical in intrauterine growth retardation. The importance of the interaction of factors like insulin-like growth factor and epidermal growth factor with their receptors is becoming increasingly clear.

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“…Low enzymatic activity in placentas of diabetic patients is not a generalized phenomenon. 22 Moreover, we found previously that placental COMT activity in these patients is not affected, 10 suggesting that the decrease in placental MAO activity in diabetes is specific.…”

Section: Discussionmentioning

confidence: 75%

“…17 As expected, the placental homogenate enzymatic activity was suppressed in the presence of butyrate. Even in well-controlled diabetes mellitus, there was an increase in both placental 22 and circulating levels of ketone bodies 23 which could have affected the placental enzyme. Low enzymatic activity in placentas of diabetic patients is not a generalized phenomenon.…”

Section: Discussionmentioning

confidence: 99%

Monoamine Oxidase Activity in the Term Human Placenta

Barnea¹,

MacLusky²,

DeCherney³

et al. 1986

Amer J Perinatol

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Using a radioenzymatic assay, placental monoamine oxidase (MAO) activity was measured at term after delivery in normal and high-risk pregnancies where decreases in placental blood flow previously were shown. MAO activity in placentas of healthy controls after spontaneous labor was similar to that after elective cesarean section not in labor (mean +/- SE, 133 +/- 18 versus 100 +/- 15 nmol/min/mg protein, respectively). Compared to controls, there was a significant reduction in placental MAO activity in high-risk pregnancies (chronic hypertension, toxemia, and diabetes mellitus), 71 +/- 14, 69 +/- 22, and 69 +/- 7, respectively (P less than 0.05). These differences also were maintained when data were expressed per total placental weight. Effects of antihypertensive drugs on MAO activity in healthy placental tissue were assessed. In homogenates, both hydralazine and magnesium sulfate reduced enzyme activity, while in explants this was not observed. The effects of certain metabolites (which are elevated in plasma of diabetic patients) on healthy homogenates also were studied. Only butyrate reduced enzyme activity. In conclusion, placental MAO activity in vitro is low in term high-risk pregnancies. This may reduce local metabolic inactivation of catecholamines and serotonin and consequently lead to a decrease in blood flow. Such a direct relationship must be confirmed in further studies.

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Metabolic Changes in Human Placental Tissue in Diabetes Mellitus

Cited by 7 publications

References 31 publications

Glucose Uptake, Utilization, and Transfer by the Human Placenta as Functions of Maternal Glucose Concentration

Glucose Uptake, Utilization, and Transfer by the Human Placenta as Functions of Maternal Glucose Concentration

The role of the placenta in fetal nutrition and growth.

Monoamine Oxidase Activity in the Term Human Placenta

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