Effects of hypoxemia and decreasing umbilical flow liver and ductus venosus blood flows in fetal lambs

Edelstone, Daniel I.; Rudolph, Abraham M.; Heymann, Michaël

doi:10.1152/ajpheart.1980.238.5.h656

Cited by 68 publications

(65 citation statements)

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“…2 and 3 are based on the assumption that microspheres injected into the UV and PV are adequately mixed within these vessels, so that their distribution within the liver accurately reflects that of portal venous and umbilical venous blood. Edelstone et al (20) have verified this assumption using a preparation very similar to that used in this study. In their study they found that paired injections into two umbilical venous tributaries were distributed similarly.…”

Section: Appendixsupporting

confidence: 67%

Hepatic oxygen and glucose metabolism in the fetal lamb. Response to hypoxia.

Bristow¹,

Rudolph²,

Itskovitz³

et al. 1983

J. Clin. Invest.

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A B S T R A C T Although the fetal liver is an active metabolic organ, its oxygen and glucose requirements have not previously been described. We measured hepatic blood flows and the oxygen and glucose differences across the liver in 12 late gestation fetal lambs in utero. Four animals were studied at least 1 wk postsurgically and again 2-5 d later to assess daily variations in hepatic blood flow and metabolism (group I). A second group of eight animals was studied 3-5 d postsurgically during a control period and during acute fetal hypoxia (group II). Under control conditions total hepatic blood flow averaged 400 ml/min per 100 g in both groups, and 75-80% was of umbilical origin. Liver blood flow and oxygen consumption were usually similar during repeated measurements, but in one animal varied considerably. During periods of normoxia, oxygen consumption for both the right and left lobes of liver was 4 ml/min per 100 g. Oxygen consumption of the whole liver accounted for 20% of total fetal oxygen consumption. This was achieved with oxygen extraction of 10-15%, so that hepatic venous blood was well oxygenated and provided an important source of oxygen for other fetal tissues. Under control conditions we could demonstrate no net hepatic uptake or release of glucose suggesting that the liver ultimately utilizes another carbon source to support its oxidative metabolism.During acute hypoxia total liver blood flow and its umbilical venous contribution both fell by 20% Received for publication 18 January 1982 and in revised form 29 December 1982. flow to the right lobe of the liver fell twice as much as that to the left lobe. Hepatic oxygen consumption was linearly related to oxygen delivery during the control and hypoxic periods. Consequently, right hepatic oxygen uptake fell by 45% whereas left hepatic oxygen uptake was unchanged, suggesting a functional difference between the lobes. During hypoxia glucose was released from both liver lobes; 6 mg/min per 100 g for the right lobe and 9 mg/min per 100 g for the left lobe. Total hepatic release of glucose was estimated to nearly equal umbilical uptake, so that 45% of the glucose available to fetal tissues was of hepatic origin. We conclude that the fetal liver responds to acute hypoxia by reducing its own oxygen consumption and releasing glucose to facilitate anaerobic metabolism.

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Section: Appendixsupporting

confidence: 67%

Hepatic oxygen and glucose metabolism in the fetal lamb. Response to hypoxia.

Bristow¹,

Rudolph²,

Itskovitz³

et al. 1983

J. Clin. Invest.

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show abstract

“…This assumption has been validated by two previous studies (1 1,12) and has recently been reassessed in our laboratory by simultaneously injecting microspheres into the two main umbilical veins, one originating from the pregnant and the other from the nonpregnant horn of the uterus. Because the two main umbilical vessels join just beyond the umbilical ring to form the common umbilical vein, microspheres injected into a peripheral umbilical vein do not pass through a mixing chamber.…”

Section: Materials a N D Methodssupporting

confidence: 56%

Effects of Ductus Venosus Obstruction on Liver and Regional Blood Flows in the Fetal Lamb

et al. 1991

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ABSTRACr'. The ductus venosus allows highly oxygenated blood returning from the umbilical-placental circulation to bypass the liver, and is believed thereby to facilitate preferential distribution of this blood to the fetal brain and heart. To examine this hypothesis, we developed a model that allows acute obstruction of the ductus venosus in chronically catheterized fetal lambs. In seven fetal lambs, a Swann-Ganz catheter was inserted into the inferior vena cava and the balloon tip advanced into the ductus venosus. Control measurements were obtained 1-2 d after surgery, before and during inflation of the balloon in the ductus venosus. At each sample time, radioactive microspheres were injected to determine organ blood flow and the distribution of umbilical venous blood flow. During balloon inflation, the percentage of umbilical venous return passing through the ductus venosus was reduced from 38 2 15% to 1 f 0.5%. Umbilical-placental blood flow was unchanged from control values of 181 f 33 mL/min/kg. Total liver blood flow increased from 346 f 98 to 553 f 105 mL/min/ 100 g. Pressure in the inferior vena cava did not change, but umbilical venous pressure increased from 7.2 2 2.7 to 8.7 f 3.5 mm Hg. Total vascular resistance across the liver and ductus venosus increased from 0.013 ? 0.006 to 0.020 2 0.011 during ductus venosus obstruction. Fetal heart rate, arterial blood pressure, and descending aortic pH and blood gases were unchanged, as was oxygen content in the descending aorta and carotid artery. Organ blood flows, combined ventricular output, and oxygen delivery were also unchanged. In five animals, these studies were repeated during maternal hypoxemia. Similar changes in liver blood flow were observed. Organ blood flows and oxygen delivery were not altered by ductus venosus obstruction during hypoxemia. We conclude that obstruction of the ductus venosus has no effect on regional blood flow distribution or oxygen delivery in normoxemic or hypoxemic animals. Because the hepatic microcirculation has such a high compliance, the ductus venosus is not crucial in regulating umbilical venous return to the central fetal circulation. (Pediatr Res 29: 347-352, 1991) Up to 50% of the blood returning from the umbilical-placental circulation passes through the ductus venosus in the fetal lamb. The rest of the blood passes through the hepatic sinusoids and then drains into the inferior vena cava. Streaming patterns in the inferior vena cava and right atrium preferentially distribute the highly oxygenated blood that passes through the ductus venosus to the fetal brain and heart (1). During umbilical cord compression (2) and fetal hemorrhage (3), increasing proportions of the blood returning in the umbilical vein from the placenta pass through the ductus venosus. These observations have suggested that the ductus venosus facilitates the preferential distribution of highly oxygenated blood to the fetal brain and heart. However, the role of the ductus venosus is uncertain. The fetal foal, swine, and guinea pig lack a duct...

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“…From the placenta, blood flows first to the liver of the fetus (where about 1/2 of the volume is received), then is preferentially shunted to the brain via the ductus venosus (Belotti et al, 2000). This shunting is known to occur during fetal life in other primates (Behrman et al, 1970)-which could reflect a common trend toward encephalization-but also in species with much smaller brain/body mass ratios such as sheep (Edelstone and Rudolph, 1979;Edelstone et al, 1978Edelstone et al, , 1980. This shunting is known to account for about 53% of the entire umbilical blood flow (Edelstone and Rudolph, 1979) and is known to increase in lambs to as much as 70% when nutrient flow is impeded (Edelstone et al, 1980).…”

Section: Discussionmentioning

confidence: 99%

Brains versus brawn: An empirical test of Barker's brain sparing model

Baker

Workman

Bedrick

et al. 2009

American J Hum Biol

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The Barker model of the in utero origins of diminished muscle mass in those born small invokes the adaptive "sparing" of brain tissue development at the expense of muscle. Though compelling, to date this model has not been directly tested. This article develops an allometric framework for testing the principal prediction of the Barker model-that among those born small muscle mass is sacrificed to spare brain growth-then evaluates this hypothesis using data from the third National Health and Nutrition Examination Survey (NHANES III). The results indicate clear support for a negative relationship between the allometric development of the two tissues; however, a further consideration of conserved mammalian fetal circulatory patterns suggests the possibility that system-constrained patterns of developmental damage and "bet-hedging" responses in affected tissues may provide a more adequate explanation of the results. Far from signaling the end of studies of adaptive developmental programming, this perspective may open a promising new avenue of inquiry within the fields of human biology and the developmental origins of health and disease.

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Effects of hypoxemia and decreasing umbilical flow liver and ductus venosus blood flows in fetal lambs

Cited by 68 publications

References 0 publications

Hepatic oxygen and glucose metabolism in the fetal lamb. Response to hypoxia.

Hepatic oxygen and glucose metabolism in the fetal lamb. Response to hypoxia.

Effects of Ductus Venosus Obstruction on Liver and Regional Blood Flows in the Fetal Lamb

Brains versus brawn: An empirical test of Barker's brain sparing model

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