Document Detail


Prolonged reductions in placental blood flow and cerebral oxygen delivery in preterm fetal sheep exposed to endotoxin: possible factors in white matter injury after acute infection.
MedLine Citation:
PMID:  12853089     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
OBJECTIVE: Endotoxin causes hypoxemia and white matter injury in the preterm ovine fetus. Because cerebral hypoxia could contribute to brain injury, our objective was to determine the effects of endotoxin on regional cerebral oxygen (O(2)) delivery. To investigate causes of fetal hypoxemia, we also measured placental blood flow. METHODS: We administered endotoxin (lipopolysaccharide, LPS) at 1 microgram/kg (intravenously) to 11 catheterized fetal sheep at approximately 0.7 of term; controls (n = 7) received saline. We measured fetal cerebral blood flow (CBF) and placental blood flow using microspheres, arterial blood gases, arterial pressure, and heart rate. RESULTS: Seven fetuses survived LPS administration (LPS-S) and four died. LPS-S fetuses were hypoxemic at 4-8 hours after LPS. Fetal hemoglobin concentration and hematocrit increased by about 14% at 4 hours after LPS exposure, and mean arterial pressure decreased significantly from 4-8 hours. After LPS, CBF did not change significantly, but total cerebral O(2) delivery decreased by 35.7% at 4 hours and by 28.3% at 8 hours. O(2) delivery to cerebral white matter decreased below pre-LPS values at 4 hours (-35.9%) and 8 hours (-28.6%) after LPS. Relative to pre-LPS values, placental blood flow decreased by 53.3% at 4 hours and 43.0% at 8 hours after LPS. CONCLUSIONS: Immature fetal sheep exposed to LPS had profound reductions in placental blood flow and cerebral O(2) delivery, which could contribute to fetal brain injury. Reduced O(2) delivery to white matter was similar to that in other brain regions. Mechanisms that enable fetal CBF to increase in hypoxemic conditions were apparently ineffective in the presence of LPS.
Authors:
P Dalitz; R Harding; S M Rees; M L Cock
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Journal of the Society for Gynecologic Investigation     Volume:  10     ISSN:  1071-5576     ISO Abbreviation:  J. Soc. Gynecol. Investig.     Publication Date:  2003 Jul 
Date Detail:
Created Date:  2003-07-10     Completed Date:  2004-03-19     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  9433806     Medline TA:  J Soc Gynecol Investig     Country:  United States    
Other Details:
Languages:  eng     Pagination:  283-90     Citation Subset:  IM    
Affiliation:
Fetal and Neonatal Research Group, Department of Physiology, Monash University, Victoria, Melbourne, Australia.
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MeSH Terms
Descriptor/Qualifier:
Animals
Arteries
Blood Flow Velocity / drug effects
Blood Pressure
Brain / blood supply,  embryology*,  metabolism
Carbon Dioxide / blood
Female
Fetal Blood / chemistry
Fetal Weight
Gestational Age
Heart Rate, Fetal
Hematocrit
Hemoglobins / analysis
Hydrogen-Ion Concentration
Lipopolysaccharides / administration & dosage*
Microspheres
Organ Size
Oxygen / blood*
Oxygen Consumption / drug effects
Placenta / blood supply*
Pregnancy
Sheep
Vascular Resistance
Chemical
Reg. No./Substance:
0/Hemoglobins; 0/Lipopolysaccharides; 124-38-9/Carbon Dioxide; 7782-44-7/Oxygen

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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