Hyperthermia prevents metabolic and cerebral flow responses to hypoxia in the fetal sheep

Suzuki, Shunji; Murata, Tomoaki; Jiang, Lan; Power, Gordon G.

doi:10.1016/s1071-5576(99)00068-4

Cited by 7 publications

(8 citation statements)

References 15 publications

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“…Intra-ischemic hyperthermia results in enhanced release of neurotransmitters, exaggerated oxygen radical production, reduced blood-brain barrier competence, enhanced inflammatory responses, impaired recovery of energy metabolism [18] and protein synthesis, and worsening of cytoskeletal proteolysis. Caspase activation is likely a final common pathway to cell death [19].…”

Section: Discussionmentioning

confidence: 99%

Impact of Hyperthermia on Inflammation-Related Perinatal Brain Injury

Seri

Rossiter²,

MacNair³

et al. 2012

Dev Neurosci

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In a rat model of perinatal inflammation and hypoxia, we investigated the impact of hyperthermia on the deleterious events which are commonly associated with chorioamnionitis. Late-pregnancy gestational day 20 rats received a single injection of either lipopolysaccharide (LPS) Escherichia coli endotoxin or saline. The offspring were born 24-36 h later at full term. The pups underwent hypoxia on the first postnatal day (PND1) immediately after which they were maintained at a planned target temperature for 2 h, before being returned to the dams. The pups were sacrificed on PND5 and the brain tissue was examined. Results showed that LPS alone or in combination with hypoxia was well tolerated. The additional stress of moderate hyperthermia (39°C for 2 h) on PND1 resulted in (a) a significant increase in brain reactive nitrogen species (RNS), (b) a significant increase in caspase-3 activity, (c) a significant increase in c-jun, bax and bcl-2 gene expression and (d) a significant increase in apoptotic cells in the CA1 region of the hippocampus. Hyperthermia was also associated with reduced growth over the ensuing 4 days in a small number of pups. In this model of perinatal inflammation, we demonstrated that brief hyperthermia when superimposed on a perinatal inflammation stimulus and hypoxia led to brain injury while either inflammation alone, or combined inflammatory stimulus and hypoxia did not cause significant damage.

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Section: Discussionmentioning

confidence: 99%

Impact of Hyperthermia on Inflammation-Related Perinatal Brain Injury

Seri

Rossiter²,

MacNair³

et al. 2012

Dev Neurosci

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“…A rise in fetal brain temperature of as little as 1°C increases the degree of neurological impairment resulting from hypoxic ischaemic injury 22 . A spontaneous and potentially protective decrease in brain temperature occurs in response to hypoxia in normothermic fetal sheep 23 . However, if its core temperature is raised by 0.7°C, the fetus may lose the innate ability to lower its brain temperature relative to its core temperature.…”

Section: Discussionmentioning

confidence: 99%

“…However, if its core temperature is raised by 0.7°C, the fetus may lose the innate ability to lower its brain temperature relative to its core temperature. Loss of this adaptation may underlie the well‐established association between intrapartum fever and hypoxic ischaemic encephalopathy 23 …”

Section: Discussionmentioning

confidence: 99%

“…22 A spontaneous and potentially protective decrease in brain temperature occurs in response to hypoxia in normothermic fetal sheep. 23 However, if its core temperature is raised by 0.7°C, the fetus may lose the innate ability to lower its brain temperature relative to its core temperature. Loss of this adaptation may underlie the well-established association between intrapartum fever and hypoxic ischaemic encephalopathy.…”

Section: Discussionmentioning

confidence: 99%

“…Loss of this adaptation may underlie the well-established association between intrapartum fever and hypoxic ischaemic encephalopathy. 23 Two phases of neuronal injury are recognised as a part of the pathophysiology of hypoxic ischaemic encephalopathy. 24 Therapeutic hypothermia in the early neonatal period is thought to provide neuroprotection by reducing metabolic demands and suppressing cytotoxic processes such as accumulation of excitatory amino acids and free radical activity.…”

Section: Discussionmentioning

confidence: 99%

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Intrauterine temperature during intrapartum amnioinfusion: a prospective observational study

Tomlinson

Schaecher

Sadovsky

et al. 2012

BJOG

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Objective To determine the influence of routine intrapartum amnioinfusion (AI) on intrauterine temperature.Design Prospective observational study.Setting Maternity unit, Barnes Jewish Hospital, St Louis, MO, USA.Sample Forty women with singleton gestations and an indication for intrapartum intrauterine pressure catheter placement.Methods Using a temperature probe, we digitally recorded intrauterine temperature every 10 minutes during labour. Amnioinfusion was administered according to a standard protocol using saline equilibrated to the ambient temperature.Main outcome measure Mean intrauterine temperature during labour.Results Participants were monitored for a mean of 280 minutes (range 20-820). A total of 164 intrauterine temperature readings in the AI cohort were compared with 797 control measurements. When compared with controls, we observed a lower intrauterine temperature in the AI cohort (36.4 versus 37.4°C, P < 0.01). More measurements in the AI cohort were recorded in the presence of intrapartum fever (40% versus 30%). A subgroup analysis of measurements recorded in afebrile parturients revealed an even greater effect of AI (1.5°C decrease, 37.3 versus 35.8°C, P < 0.01).Conclusion Routine intrapartum AI using saline equilibrated to a mean ambient temperature of 25.0°C reduces intrauterine temperature and may thereby affect fetal core temperature.

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Effects of Perceived Treatment on Quality of Life and Medical Outcomesin a Double-blind Placebo Surgery Trial

McRae¹,

Cherin²,

Yamazaki³

et al. 2004

Arch Gen Psychiatry

238

154

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Hyperthermia prevents metabolic and cerebral flow responses to hypoxia in the fetal sheep

Abstract: When temperature of the fetal sheep is elevated, as may occur with maternal fever, prolonged exercise, and elevated environmental temperatures, the fetal brain is less well protected against hypoxic injury.

Cited by 7 publications

References 15 publications

Impact of Hyperthermia on Inflammation-Related Perinatal Brain Injury

Impact of Hyperthermia on Inflammation-Related Perinatal Brain Injury

Intrauterine temperature during intrapartum amnioinfusion: a prospective observational study

Effects of Perceived Treatment on Quality of Life and Medical Outcomesin a Double-blind Placebo Surgery Trial

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