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Chilakala SK, Parfenova H, Pourcyrous M. The effects of sodium bicarbonate infusion on cerebrovascular function in newborn pigs. Pediatr Res 2022; 92:729-736. [PMID: 34862458 PMCID: PMC9163205 DOI: 10.1038/s41390-021-01876-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Revised: 11/11/2021] [Accepted: 11/13/2021] [Indexed: 11/09/2022]
Abstract
BACKGROUND Sodium bicarbonate (NaHCO3) is no longer recommended by the Neonatal Resuscitation Program (NRP), but is still being used by some neonatologists. The effects of NaHCO3 on cerebral hemodynamics are unclear. Therefore, we investigated the effects of NaHCO3 on cerebral blood flow (CBF) and cerebrovascular function using a newborn piglet model. METHODS Newborn pigs were anesthetized, intubated, and ventilated. Cranial windows were implanted to evaluate changes in pial arteriolar diameters (PADs) as a surrogate for CBF during a 4-h intravenous infusion of 3% NaHCO3. Cerebrovascular reactivity to vasodilators and vasoconstrictors was investigated during vehicle control and during NaHCO3 infusion. RESULTS NaHCO3 infusion caused significant and progressive pial arteriolar vasoconstrictions. During NaHCO3 infusion, cerebrovascular reactivity was preserved. Adding vasodilators decreased cerebral vasoconstriction, while adding vasoconstrictors exaggerated cerebral vasoconstriction. CONCLUSIONS Intravenous infusion of NaHCO3 over 4 h caused progressive vasoconstriction of pial arterioles. Cerebrovascular function evaluated by the responses of pial arterioles to physiologically relevant vasoconstrictors and vasodilators was preserved during NaHCO3 infusion. A notable additional reduction of PADs was observed during NaHCO3 infusion in the presence of vasoconstrictors. Extrapolating our findings to human neonates should alarm the clinicians that using NaHCO3 in neonates may cause cerebral hypoperfusion. IMPACT Cerebral vasoconstriction occurs during slow infusion of 3% diluted NaHCO3. Cerebral vasoconstriction is exaggerated when another vasoconstrictor is added during NaHCO3 infusion. Cerebrovascular function is preserved during NaHCO3 infusion. Clinicians should be aware of the risk of cerebral hypoperfusion with NaHCO3 infusion in vulnerable neonates.
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Affiliation(s)
- Sandeep K Chilakala
- Department of Pediatrics, University of Tennessee Health Science Center (UTHSC), Memphis, Tennessee
| | - Helena Parfenova
- Department of Physiology, University of Tennessee Health Science Center (UTHSC), Memphis, Tennessee
| | - Massroor Pourcyrous
- Department of Pediatrics, University of Tennessee Health Science Center (UTHSC), Memphis, TN, USA. .,Department of Physiology, University of Tennessee Health Science Center (UTHSC), Memphis, TN, USA. .,Department of Obstetrics/Gynecology, University of Tennessee Health Science Center (UTHSC), Memphis, TN, USA.
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Does prolonged severe hypercapnia interfere with normal cerebrovascular function in piglets? Pediatr Res 2018; 84:290-295. [PMID: 29907849 PMCID: PMC6185793 DOI: 10.1038/s41390-018-0061-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Revised: 04/16/2018] [Accepted: 04/17/2018] [Indexed: 11/21/2022]
Abstract
BACKGROUND Hypercapnia causes cerebral vasodilation and increased cerebral blood flow (CBF). During prolonged hypercapnia it is unknown whether cerebral vasodilation persists and whether cerebrovascular function is preserved. We investigated the effects of prolonged severe hypercapnia on pial arteriolar diameters (PAD) and cerebrovascular reactivity to vasodilators and vasoconstrictors. METHODS Piglets were anesthetized, intubated and ventilated. Closed cranial windows were implanted to measure PAD. Changes in PAD were documented during hypercapnia (PaCO2 75-80 mm Hg). Cerebrovascular reactivity was documented during normocapnia and at 30, 60, and 120 min of hypercapnia. RESULTS Cerebral vasodilation to hypercapnia was sustained over 120 min. Cerebrovascular responses to vasodilators and vasoconstrictors were preserved during hypercapnia. During hypercapnia, vasodilatory responses to second vasodilators were similar to normocapnia, while exposure to vasoconstrictors caused significant vasoconstriction. CONCLUSIONS Prolonged severe hypercapnia causes sustained vasodilation of pial arteriolar diameters indicative of hyperperfusion. During hypercapnia, cerebral vascular responses to vasodilators and vasoconstrictors were preserved, suggesting that cerebral vascular function remained intact. Of note, cerebral vessels during hypercapnia were capable of further dilation when exposed to additional cerebral vasodilators and, significant vasoconstriction when exposed to vasoconstrictors. Extrapolating these findings to infants, we suggest that severe hypercapnia should be avoided, because it could cause/increase cerebrovascular injury.
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Parfenova H, Pourcyrous M, Fedinec AL, Liu J, Basuroy S, Leffler CW. Astrocyte-produced carbon monoxide and the carbon monoxide donor CORM-A1 protect against cerebrovascular dysfunction caused by prolonged neonatal asphyxia. Am J Physiol Heart Circ Physiol 2018; 315:H978-H988. [PMID: 30028198 DOI: 10.1152/ajpheart.00140.2018] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Neonatal asphyxia leads to cerebrovascular disease and neurological complications via a mechanism that may involve oxidative stress. Carbon monoxide (CO) is an antioxidant messenger produced via a heme oxygenase (HO)-catalyzed reaction. Cortical astrocytes are the major cells in the brain that express constitutive HO-2 isoform. We tested the hypothesis that CO, produced by astrocytes, has cerebroprotective properties during neonatal asphyxia. We developed a survival model of prolonged asphyxia in newborn pigs that combines insults of severe hypoxia, hypercapnia, and acidosis while avoiding extreme hypotension and cerebral blood flow reduction. During the 60-min asphyxia, CO production by brain and astrocytes was continuously elevated. Excessive formation of reactive oxygen species during asphyxia/reventilation was potentiated by the HO inhibitor tin protoporphyrin, suggesting that endogenous CO has antioxidant effects. Cerebral vascular outcomes tested 24 and 48 h after asphyxia demonstrated the sustained impairment of cerebral vascular responses to astrocyte- and endothelium-specific vasodilators. Postasphyxia cerebral vascular dysfunction was aggravated in newborn pigs pretreated with tin protoporphyrin to inhibit brain HO/CO. The CO donor CO-releasing molecule-A1 (CORM-A1) reduced brain oxidative stress during asphyxia/reventilation and prevented postasphyxia cerebrovascular dysfunction. The antioxidant and antiapoptotic effects of HO/CO and CORM-A1 were confirmed in primary cultures of astrocytes from the neonatal pig brain exposed to glutamate excitotoxicity. Overall, prolonged neonatal asphyxia leads to neurovascular injury via an oxidative stress-mediated mechanism that is counteracted by an astrocyte-based constitutive antioxidant HO/CO system. We propose that gaseous CO or CO donors can be used as novel approaches for prevention of neonatal brain injury caused by prolonged asphyxia. NEW & NOTEWORTHY Asphyxia in newborn infants may lead to lifelong neurological disabilities. Using the model of prolonged asphyxia in newborn piglets, we propose novel antioxidant therapy based on systemic administration of low doses of a carbon monoxide donor that prevent loss of cerebral blood flow regulation and may improve the neurological outcome of asphyxia.
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Affiliation(s)
- Helena Parfenova
- Departments of Physiology and Pediatrics, University of Tennessee Health Science Center , Memphis, Tennessee
| | - Massroor Pourcyrous
- Departments of Physiology and Pediatrics, University of Tennessee Health Science Center , Memphis, Tennessee
| | - Alex L Fedinec
- Departments of Physiology and Pediatrics, University of Tennessee Health Science Center , Memphis, Tennessee
| | - Jianxiong Liu
- Departments of Physiology and Pediatrics, University of Tennessee Health Science Center , Memphis, Tennessee
| | - Shyamali Basuroy
- Departments of Physiology and Pediatrics, University of Tennessee Health Science Center , Memphis, Tennessee
| | - Charles W Leffler
- Departments of Physiology and Pediatrics, University of Tennessee Health Science Center , Memphis, Tennessee
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Pourcyrous M, Basuroy S, Tcheranova D, Arheart KL, Elabiad MT, Leffler CW, Parfenova H. Brain-derived circulating endothelial cells in peripheral blood of newborn infants with seizures: a potential biomarker for cerebrovascular injury. Physiol Rep 2015; 3:3/3/e12345. [PMID: 25804265 PMCID: PMC4393173 DOI: 10.14814/phy2.12345] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Neonatal seizures have been associated with cerebrovascular endothelial injury and neurological disabilities. In a piglet model, the long-term loss of endothelial regulation of cerebral blood flow coincides with the surge of brain-derived circulating endothelial cells (BCECs) in blood. We hypothesized that BCECs could serve as a noninvasive biomarker of cerebrovascular injury in neonates with seizures. In a prospective pilot feasibility study, we enrolled newborn infants with confirmed diagnoses of perinatal asphyxia and intraventricular hemorrhage (IVH); both are commonly associated with seizures. Infants without clinical evidence of cerebrovascular injuries were representative of the control group. BCECs were detected in the CD45-negative fraction of peripheral blood mononuclear cells by coexpression of CD31 (common endothelial antigen) and GLUT1 (blood-brain barrier antigen) via automated flow cytometry method. In Infants with asphyxia (n = 12) and those with IVH grade III/IV (n = 5), the BCEC levels were 9.9 ± 0.9% and 19.0 ± 2.0%, respectively. These levels were significantly higher than the control group (n = 27), 0.9 ± 0.2%, P < 0.001. BCECs in infants with cerebrovascular insults with documented clinical seizures (n = 10; 16.8 ± 1.3%) were significantly higher than infants with cerebrovascular insults with subclinical or no seizures (n = 7; 9.5 ± 1.2%); P < 0.001. BCEC levels decreased with seizure control. BCECs levels were elevated in infants with seizures caused by severe IVH and perinatal asphyxia. We suggest that monitoring BCEC levels in peripheral blood can potentially offer a biological marker that reflects cerebrovascular insult and recovery. Further studies with a larger number of patients are required to support these findings.
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Affiliation(s)
- Massroor Pourcyrous
- Department of Pediatrics, The University of Tennessee Health Science Center (UTHSC), Memphis, Tennessee Department of Physiology, The University of Tennessee Health Science Center (UTHSC), Memphis, Tennessee Department of Neuroscience Institute, The University of Tennessee Health Science Center (UTHSC), Memphis, Tennessee Department of Obstetrics and Gynecology, The University of Tennessee Health Science Center (UTHSC), Memphis, Tennessee
| | - Shyamali Basuroy
- Department of Physiology, The University of Tennessee Health Science Center (UTHSC), Memphis, Tennessee
| | - Dilyara Tcheranova
- Department of Physiology, The University of Tennessee Health Science Center (UTHSC), Memphis, Tennessee
| | - Kristopher L Arheart
- Division of Biostatistics and Pediatrics, Department of Public Health Sciences, Miller School of Medicine University of Miami, Coral Gables, Florida
| | - Mohamad T Elabiad
- Department of Pediatrics, The University of Tennessee Health Science Center (UTHSC), Memphis, Tennessee
| | - Charles W Leffler
- Department of Pediatrics, The University of Tennessee Health Science Center (UTHSC), Memphis, Tennessee Department of Physiology, The University of Tennessee Health Science Center (UTHSC), Memphis, Tennessee Department of Neuroscience Institute, The University of Tennessee Health Science Center (UTHSC), Memphis, Tennessee
| | - Helena Parfenova
- Department of Physiology, The University of Tennessee Health Science Center (UTHSC), Memphis, Tennessee Department of Neuroscience Institute, The University of Tennessee Health Science Center (UTHSC), Memphis, Tennessee
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Joynt C, Bigam DL, Charrois G, Jewell LD, Korbutt G, Cheung PY. Milrinone, dobutamine or epinephrine use in asphyxiated newborn pigs resuscitated with 100% oxygen. Intensive Care Med 2010; 36:1058-66. [DOI: 10.1007/s00134-010-1820-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2009] [Accepted: 11/28/2009] [Indexed: 11/24/2022]
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Fabian RH, Perez-Polo JR, Kent TA. Perivascular nitric oxide and superoxide in neonatal cerebral hypoxia-ischemia. Am J Physiol Heart Circ Physiol 2008; 295:H1809-14. [PMID: 18676689 PMCID: PMC2593505 DOI: 10.1152/ajpheart.00301.2007] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/09/2007] [Accepted: 07/28/2008] [Indexed: 11/22/2022]
Abstract
Decreased cerebral blood flow (CBF) has been observed following the resuscitation from neonatal hypoxic-ischemic injury, but its mechanism is not known. We address the hypothesis that reduced CBF is due to a change in nitric oxide (NO) and superoxide anion O(2)(-) balance secondary to endothelial NO synthase (eNOS) uncoupling with vascular injury. Wistar rats (7 day old) were subjected to cerebral hypoxia-ischemia by unilateral carotid occlusion under isoflurane anesthesia followed by hypoxia with hyperoxic or normoxic resuscitation. Expired CO(2) was determined during the period of hyperoxic or normoxic resuscitation. Laser-Doppler flowmetry was used with isoflurane anesthesia to monitor CBF, and cerebral perivascular NO and O(2)(-) were determined using fluorescent dyes with fluorescence microscopy. The effect of tetrahydrobiopterin supplementation on each of these measurements and the effect of apocynin and N(omega)-nitro-L-arginine methyl ester (L-NAME) administration on NO and O(2)(-) were determined. As a result, CBF in the ischemic cortex declined following the onset of resuscitation with 100% O(2) (hyperoxic resuscitation) but not room air (normoxic resuscitation). Expired CO(2) was decreased at the onset of resuscitation, but recovery was the same in normoxic and hyperoxic resuscitated groups. Perivascular NO-induced fluorescence intensity declined, and O(2)(-)-induced fluorescence increased in the ischemic cortex after hyperoxic resuscitation up to 24 h postischemia. L-NAME treatment reduced O(2)(-) relative to the nonischemic cortex. Apocynin treatment increased NO and reduced O(2)(-) relative to the nonischemic cortex. The administration of tetrahydrobiopterin following the injury increased perivascular NO, reduced perivascular O(2)(-), and increased CBF during hyperoxic resuscitation. These results demonstrate that reduced CBF follows hyperoxic resuscitation but not normoxic resuscitation after neonatal hypoxic-ischemic injury, accompanied by a reduction in perivascular production of NO and an increase in O(2)(-). The finding that tetrahydrobiopterin, apocynin, and L-NAME normalized radical production suggests that the uncoupling of perivascular NOS, probably eNOS, due to acquired relative tetrahydrobiopterin deficiency occurs after neonatal hypoxic-ischemic brain injury. It appears that both NOS uncoupling and the activation of NADPH oxidase participate in the changes of reactive oxygen concentrations seen in cerebral hypoxic-ischemic injury.
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MESH Headings
- Acetophenones/pharmacology
- Animals
- Animals, Newborn
- Biopterins/analogs & derivatives
- Biopterins/pharmacology
- Carbon Dioxide/metabolism
- Cerebral Cortex/blood supply
- Cerebrovascular Circulation/drug effects
- Disease Models, Animal
- Endothelium, Vascular/drug effects
- Endothelium, Vascular/metabolism
- Endothelium, Vascular/physiopathology
- Enzyme Inhibitors/pharmacology
- Exhalation
- Hypoxia-Ischemia, Brain/metabolism
- Hypoxia-Ischemia, Brain/pathology
- Hypoxia-Ischemia, Brain/physiopathology
- Hypoxia-Ischemia, Brain/therapy
- Laser-Doppler Flowmetry
- Microscopy, Fluorescence
- NADPH Oxidases/antagonists & inhibitors
- NADPH Oxidases/metabolism
- NG-Nitroarginine Methyl Ester/pharmacology
- Nitric Oxide/metabolism
- Nitric Oxide Synthase Type II/antagonists & inhibitors
- Nitric Oxide Synthase Type II/metabolism
- Nitric Oxide Synthase Type III/antagonists & inhibitors
- Nitric Oxide Synthase Type III/metabolism
- Oxygen Inhalation Therapy/adverse effects
- Rats
- Rats, Wistar
- Resuscitation/adverse effects
- Superoxides/metabolism
- Time Factors
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Affiliation(s)
- Roderic H Fabian
- Department of Neurology, Baylor College of Medicine and the Michael E. DeBakey Veterans Affairs Medical Center Stroke Program, Houston 77030, USA.
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Dose-response effects of milrinone on hemodynamics of newborn pigs with hypoxia-reoxygenation. Intensive Care Med 2008; 34:1321-9. [DOI: 10.1007/s00134-008-1060-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2007] [Accepted: 02/01/2008] [Indexed: 11/25/2022]
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8
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Azra Haider B, Bhutta ZA. Birth asphyxia in developing countries: current status and public health implications. Curr Probl Pediatr Adolesc Health Care 2006; 36:178-88. [PMID: 16631096 DOI: 10.1016/j.cppeds.2005.11.002] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Affiliation(s)
- Batool Azra Haider
- Department of Paediatrics and Child Health, The Aga Khan University, Karachi, Pakistan
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Abstract
Germinal matrix hemorrhage refers to bleeding that arises from the subependymal (or periventricular) germinal region of the immature brain. Clinical studies have shown that infants who experience germinal matrix hemorrhage can develop hydrocephalus or suffer from long-term neurologic dysfunction, including cerebral palsy, seizures, and learning disabilities. Understanding the causative factors and the pathogenesis of subsequent brain damage is important if germinal matrix hemorrhage is to be prevented or treated. Appropriate animal models are necessary to achieve this understanding. A number of animal species, including mice, rats, rabbits, sheep, pigs, dogs, cats, and primates, have been used to model germinal matrix hemorrhage. This literature review critically evaluates the animal models of germinal matrix hemorrhage. Each model has its own advantages and disadvantages; no single model is suitable for the study of all aspects of brain damage.
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Affiliation(s)
- Janani Balasubramaniam
- Department of Pathology, University of Manitoba and Manitoba Instititute of Child Health, Winnipeg, MB, Canada
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10
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Pourcyrous M, Bada HS, Blaho KE, Randolph MM, Parfenova H, Mandrell TD, Arheart K, Korones SB, Leffler CW. Chronic prenatal exposure to cocaine alters cerebrovascular responses in newborn pigs. Exp Biol Med (Maywood) 2004; 229:819-25. [PMID: 15337837 DOI: 10.1177/153537020422900815] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Maternal cocaine abuse may increase the incidence of perinatal asphyxia. In nonexposed asphyxiated neonates, decreased cerebrospinal fluid (CSF) cAMP concentrations are associated with poor neurological outcome. On the other hand, cocaine increases central nervous system (CNS) cAMP. Therefore, we hypothesized that in utero cocaine exposure may increase brain cAMP and thereby preserve cerebrovascular responses to cAMP-dependent stimuli following asphyxia. Pregnant pigs received either cocaine (1 mg/kg, i.v.) twice weekly during the last trimester or normal saline vehicle (sham-control) and were allowed to deliver vaginally at term. Cranial windows were implanted in the newborn pigs within the first week of life and used to collect CSF for cAMP determinations and to assess changes in pial arteriolar diameters (PAD). In the first part of the study, pial arteriolar responses to different vasodilator and vasoconstrictor stimuli were evaluated in piglets prior to asphyxia (n = 20). In newborn pigs exposed to cocaine, cerebrovascular responses to hypercapnia and norepinephrine were significantly exaggerated compared to controls. Then, piglets were randomly selected for the second part of the study that involved prolonged asphyxia (n = 12). In cocaine-exposed but not sham-control piglets, CSF cAMP increased markedly during asphyxia. In the sham piglets, but not the cocaine-exposed piglets, CSF cAMP fell progressively below the baseline during recovery. Cerebrovascular reactivity to cAMP-dependent stimuli (hypercapnia and isoproterenol) was preserved during recovery from asphyxia in the cocaine-exposed piglets but significantly attenuated in the sham controls. We conclude that piglets with chronic prenatal exposure to cocaine show exaggerated cerebrovascular responses to vasogenic stimuli and preserved cAMP-dependent cerebral vasoreactivity following asphyxia.
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Affiliation(s)
- Massroor Pourcyrous
- Laboratory for Research in Neonatal Physiology, Department of Pediatrics, The University of Tennessee Health Science Center, Memphis, Tennessee 38163, USA.
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Daley ML, Pourcyrous M, Timmons SD, Leffler CW. Intracranial pressure dynamics: changes of bandwidth as an indicator of cerebrovascular tension. Med Eng Phys 2003; 25:679-89. [PMID: 12900183 DOI: 10.1016/s1350-4533(03)00077-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The transmission bandwidth (BW) of arterial blood pressure (ABP) to intracranial pressure (ICP) was examined as a means of bedside monitoring of the state of cerebrovascular tension. Changes of BW of a black box identification model, relative arteriolar resistance and intracranial compliance were obtained from a piglet model equipped with a cranial window during induction of asphyxia, hypercapnia, and hypoxia. Changes of black box BW values and simulated changes of BW produced by a physiologically based lump parameter model of ICP dynamics are used to evaluate the hypothesis that during active cerebrovascular tension, changes of BW are inversely related to cerebral perfusion pressure (CPP), and during passive cerebrovascular tension, changes of BW are not inversely related to changes of CPP. Induction of asphyxia (n = 3) produced BW changes of the black box model that were simulated as an active cerebrovascular tension phase during decreasing CPP followed by a passive tension phase. Reventilation after prolonged asphyxia produced significant increases of BW that were simulated by a passive tension. Hypercapnic (n = 6) and hypoxic (n = 6) challenges produced: (1) significant changes of BW that were matched with simulations of the lumped parameter model for active tension; and (2) relationships between values of BW and relative average cerebral arteriolar resistance and intracranial compliance were inverse and correlated to a regression function of approximately x(-1). Changes of BW of the black box model and the simulations of the lumped parameter model support the feasibility of the stated hypothesis. As such, the evaluation of changes of BW of the black box model with respect to changes of CPP may be a useful method for monitoring the state of cerebrovascular tension.
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Affiliation(s)
- Michael L Daley
- Department of Electrical and Computer Engineering, The University of Memphis, Engineering Science Building, Rm. 208B, Central Avenue, Memphis, TN 38152-6574, USA
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Daley ML, Pourcyous M, Willis A, Leffler CW. Variation of proposed correlation indices of cerebrovascular reactivity with change of arteriolar diameter. ACTA NEUROCHIRURGICA. SUPPLEMENT 2003; 81:151-3. [PMID: 12168290 DOI: 10.1007/978-3-7091-6738-0_39] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
The purpose of this study was to examine the relationship between proposed correlation indices of cerebrovascular reserve and corresponding changes of cerebrovascular reserve as measured by changes of pial arteriolar diameter. Mild and severe physiologic challenge was produced in piglets by appropriate ventilation with foreign gas mixture and altered alveolar ventilation. Intracranial pressure (ICP), arterial blood pressure (ABP), and video micrometer recordings of pial arteriolar diameter were made. Serial values of ICP and ABP were used to compute the Correlation Coefficient index (Corrx) and the Pressure Reactivity Index (PrX). For the 10 mild physiologic challenge experiments, correlations between percent change index (% delta Corrx and % delta PrX) and percent change of pial arteriolar diameter (% delta dia.) induced by mild challenges (n = 40) were 0.51 (p < .005) and 0.097 (p n.s.) respectively. For 8 asphyxia experiments, serial values with respect to time of the correlation indices were correlated with % delta dia. obtained before, during induction and recovery. The grand mean (n = 8) correlation values (+/- S.D.) of the Corrx and PrX were 0.76 (+/- 0.18, p < .025) and 0.21 (+/- 0.38, p n.s.) respectively. In contrast to the PrX index, changes of the Corrx index significantly correlated with changes of pial arteriolar diameter. However, Corrx and PrX were simultaneously high only during a state of maximum dilation. These findings suggest that sudden salient increases of the Corrx and PrX indices induced by physiologic challenge are indicative of vigorous dilatory response of the cerebral arterioles and loss of cerebrovascular reserve.
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Affiliation(s)
- M L Daley
- Department of Electrical and Computer Engineering, University of Memphis, Memphis, TN, USA
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13
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Pourcyrous M, Bada HS, Parfenova H, Daley ML, Korones SB, Leffler CW. Cerebrovasodilatory contribution of endogenous carbon monoxide during seizures in newborn pigs. Pediatr Res 2002; 51:579-85. [PMID: 11978880 DOI: 10.1203/00006450-200205000-00006] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Carbon monoxide (CO) and the excitatory amino acid glutamate both dilate cerebral arterioles in newborn pigs. The key enzyme in CO synthesis is heme oxygenase, which is highly expressed in neurons with glutamatergic receptor activity as well as cerebral microvessels. During seizures the extracellular level of glutamate is increased, which results in excessive depolarization of neurons. We hypothesized that CO is a mediator of excitatory amino acid-induced dilation of the cerebral microvasculature during seizures. Three groups of piglets were examined: 1) i.v. normal saline (sham control), 2) topical chromium mesoporphyrin (Cr-MP, 15 x 10(-6) M), and 3) i.v. tin-protoporphyrin (Sn-PP, 4 mg/kg). Synthetic metalloporphyrins (Cr-MP and Sn-PP) are heme oxygenase inhibitors, thereby reducing CO synthesis. Implanted closed cranial windows were used to monitor changes in pial arteriolar diameters. Seizures were induced by administration of i.v. bicuculline. Changes in pial arteriolar diameters were monitored during 30 min of status epilepticus. The percent increase in pial arteriolar dilation in the saline group during seizures was 68 +/- 3%. In the metalloporphyrin groups, the pial arteriolar dilation was markedly reduced (35 +/- 3% and 13 +/- 1%, for Cr-MP and Sn-PP, respectively; p < 0.05, compared with the saline group). We conclude that metalloporphyrins by inhibition of heme oxygenase and prevention of CO synthesis attenuate pial arteriolar dilation during seizures. Therefore, CO appears to be involved in cerebral vasodilation caused by glutamatergic seizures.
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Affiliation(s)
- Massroor Pourcyrous
- Laboratory for Research in Neonatal Physiology, Departments of Pediatrics, The University of Tennessee Health Sciences Center, Memphis, Tennessee 38163, USA.
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Saiki C, Ikeda M, Nishikawa T, Tanimoto T, Yoshida S, Matsumoto S. The process of cardiorespiratory autoresuscitation in intact newborn rats. Can J Physiol Pharmacol 2001. [DOI: 10.1139/y01-090] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
To examine the process of spontaneous autoresuscitation and the recovery of the hypoxic ventilatory response (HVR) after prolonged anoxia, we monitored respiratory frequency (f, by body plethysmography) and heart rate (HR, by ECG) in intact newborn rats (n = 12, day 24) before, during, and after 100% N2 exposure. The rat before anoxia showed signs of HVR: f changes at acute hypoxia (10% O2) and hyperoxia (100% O2). During anoxia, the spontaneous respiratory movement "gasping" appeared for 21 min (mean). At O2 restoration (with 100% O2), gasping stopped and no respiratory flow was detected for 1 min. One rat failed to autoresuscitate and had heart arrhythmia during the transient apnea, but 11 rats recovered respiration after the HR acceleration. Despite the successful autoresuscitation, the rats did not show HVR at 10 min into the recovery period and the recovery of HVR required more than 30 min. The results indicate that O2 inhalation is useful to trigger autoresuscitation even when the rat has already been in a state of profound hypoxic depression, but the rat becomes transiently insensitive to HVR after autoresuscitation. We estimate that reform of the respiratory control system in newborn rats is not yet firmly established to track HVR early in the recovery phase after prolonged anoxia.Key words: anoxia, hypoxic ventilatory response, cardiopulmonary resuscitation (CPR), sudden infant death (SID).
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Temesvári P, Karg E, Bódi I, Németh I, Pintér S, Lazics K, Domoki F, Bari F. Impaired early neurologic outcome in newborn piglets reoxygenated with 100% oxygen compared with room air after pneumothorax-induced asphyxia. Pediatr Res 2001; 49:812-9. [PMID: 11385143 DOI: 10.1203/00006450-200106000-00017] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Birth asphyxia is a serious problem worldwide, resulting in 1 million deaths and an equal number of neurologic sequelae annually. It is therefore important to develop new and better ways to treat asphyxia. In the present study we tested the effects of reoxygenation with room air or with 100% oxygen (O2) after experimental pneumothorax-induced asphyxia on the blood oxidative stress indicators, early neurologic outcome, and cerebral histopathology of newborn piglets. Twenty-six animals were studied in three experimental groups: 1) sham-operated animals (SHAM, n = 6), 2) animals reoxygenated with room air after pneumothorax (R21, n = 10), and 3) animals reoxygenated with 100% O2 after pneumothorax (R100, n = 10). In groups R21 and R100, asphyxia was induced under anesthesia with bilateral intrapleural room air insufflation. Gasping, bradyarrhythmia, arterial hypotension, hypoxemia, hypercarbia, and combined acidosis occurred 62 +/- 6 min (R21) or 65 +/- 7 min (R100; mean +/- SD) after the start of the experiments; then pneumothorax was relieved, and a 10-min reoxygenation period was started with mechanical ventilation with room air (R21) or with 100% O2 (R100). The newborn piglets then breathed room air spontaneously during the next 3 h. Blood oxidative stress indicators (oxidized and reduced glutathione, plasma Hb, and malondialdehyde concentrations) were measured at different stages of the experiments. Early neurologic outcome examinations (neurologic score of 20 indicates normal, 5 indicates brain-dead) were performed at the end of the study. The brains were next fixed, and various regions were stained for cerebral histopathology. In the SHAM group, the blood gas and acid-base status differed significantly from those measured in groups R21 and R100. In group R100, arterial PO2 was significantly higher after 5 (13.8 +/- 5.6 kPa) and 10 min (13.2 +/- 6.3 kPa) of reoxygenation than in group R21 (8.7 +/- 2.8 kPa and 9.2 +/- 3.1 kPa). The levels of all oxidative stress indicators remained unchanged in the study groups (SHAM, R21, and R100). The neurologic examination score in the SHAM group was 18 +/- 0, in group R21 it was 13.5 +/- 3.1, and in group R100 it was 9.5 +/- 4.1 (significant differences between SHAM and R21 or R100, and between R21 and R100). Cerebral histopathology revealed marked damage of similar severity in both asphyxiated groups. We conclude that the blood oxidative stress indicators and cerebral histopathology did not differ significantly after a 10-min period of reoxygenation with room air or with 100% O2 after pneumothorax-induced asphyxia, but reoxygenation with 100% O2 might impair the early neurologic outcome of newborn piglets.
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Affiliation(s)
- P Temesvári
- Department of Pediatrics, University Teaching Hospital, Kecskemét, Hungary.
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Scher M. Perinatal asphyxia: timing and mechanisms of injury in neonatal encephalopathy. Curr Neurol Neurosci Rep 2001; 1:175-84. [PMID: 11898514 DOI: 10.1007/s11910-001-0014-x] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
This article summarizes the recent medical literature regarding perinatal asphyxia with respect to timing and mechanisms of injury for neonates who were clinically diagnosed with an encephalopathy in the newborn period. Multiple mechanisms of injury are reviewed, including genetic vulnerability, acquired inflammatory responses, and clotting defects that can lead to ischemic-induced brain damage. Before effective treatments for fetal and neonatal brain disorders can be developed, accurate and timely diagnoses of fetal or neonatal brain injury must be achieved. Specific subsets of children can then benefit from neuroprotective strategies that can target the specific developmental aspects of brain adaptation or plasticity relative to the specific etiology and timing of injury after asphyxia.
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Affiliation(s)
- M Scher
- Division of Pediatrics and Neurology, Rainbow Babies and Children's Hospital, Case Western Reserve University, 11100 Euclid Avenue, Cleveland, OH 44106-6090, USA.
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Levine V, Pourcyrous M, Bada HS, Parfenova H, Yang W, Korones SB, Leffler CW. Preservation of cerebrovascular tone and reactivity by sodium channel inhibition in experimental prolonged asphyxia in piglets. Pediatr Res 2000; 47:376-80. [PMID: 10709738 DOI: 10.1203/00006450-200003000-00015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Sodium channels using cAMP as a second messenger play a role in the regulation of cerebral circulation and metabolism. Cerebrospinal fluid (CSF) cAMP levels have been shown to correlate with the degree and duration of hypoxic injury and outcome and to be an indicator of cerebral vascular reactivity. We hypothesize that sodium channel inhibition either before or at termination of experimental asphyxia will attenuate cerebrovascular alterations and maintain CSF cAMP levels. Three groups of piglets with closed cranial windows were studied: asphyxia or group 1 (n = 5) and two treatment groups. Pigs were treated with 50 mg/kg of sodium channel blocker before asphyxia (group 2, n = 6) and after the termination of asphyxia and start of reventilation (group 3, n = 6). Asphyxia was sustained over 60 min by ventilating piglets with 10% O2 gas mixture and decreasing minute ventilation followed by 60 min of reventilation with room air. Every 10 min, pial arterial diameters were measured, and CSF samples were collected for cAMP determination. Vascular reactivity to topically applied isoproterenol (10(-4) M) was evaluated 60 min after recovery. During asphyxia, cAMP levels in group 2 peaked and declined at a later time with mean values remaining significantly higher than those of groups 1 and 3. During reventilation, CSF cAMP concentrations were highest in group 3 and lowest in group 1. Pial arteriolar dilation occurred during asphyxia in all three groups but to a lesser degree in the pretreated group compared with groups 1 and 3. Pial arteriolar reactivity to isoproterenol postasphyxia was preserved in both groups 2 and 3. In summary, in newborn pigs, pretreatment with sodium channel blocker resulted in higher CSF cAMP levels and a lesser degree of pial arteriolar dilation during prolonged asphyxia. Pretreatment or treatment at reventilation restored vascular tone and reactivity.
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Affiliation(s)
- V Levine
- Department of Pediatrics, The University of Tennessee, Memphis 38163, USA
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Bennet L, Quaedackers JS, Gunn AJ, Rossenrode S, Heineman E. The effect of asphyxia on superior mesenteric artery blood flow in the premature sheep fetus. J Pediatr Surg 2000; 35:34-40. [PMID: 10646770 DOI: 10.1016/s0022-3468(00)80009-3] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND/PURPOSE The aim of this study was to determine superior mesenteric artery blood flow changes during and after an asphyxial insult in utero in chronically instrumented unanaesthetised premature fetal sheep. METHODS Fetal sheep at 0.7 gestation (103 to 104 days) underwent 25 minutes of complete umbilical cord occlusion (n = 6) or sham occlusion (n = 6). Fetal heart rate, blood pressure, superior mesenteric artery (SMA) blood flow and vascular resistance, electroencephalographic activity, and nuchal electromyographic activity were measured from 6 hours before occlusion until 3 days after occlusion. Fetal gastrointestinal tissue was taken for histological assessment. RESULTS During occlusion, cardiovascular response was characterised by 3 phases: initial redistribution of blood flow away from the gut to maintain vital organ function, subsequently partial failure of this redistribution, and finally near terminal cardiovascular collapse with profound hypotension and gastrointestinal hypoperfusion. Postasphyxia there was a secondary period of hypoperfusion that was mediated by increased vascular resistance, not hypotension. There was no evidence of injury on standard histological assessment after 3 days of recovery. CONCLUSIONS SMA blood flow is not only significantly reduced during asphyxia, but also for several hours after an asphyxial insult. The authors speculate that these perturbations of gastrointestinal blood flow could compromise gut wall integrity potentially leading to increased vulnerability to necrotising enterocolitis.
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Affiliation(s)
- L Bennet
- Research Centre for Developmental Medicine and Biology, Department of Paediatrics, The University of Auckland, New Zealand
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Bennet L, Rossenrode S, Gunning MI, Gluckman PD, Gunn AJ. The cardiovascular and cerebrovascular responses of the immature fetal sheep to acute umbilical cord occlusion. J Physiol 1999; 517 ( Pt 1):247-57. [PMID: 10226163 PMCID: PMC2269318 DOI: 10.1111/j.1469-7793.1999.0247z.x] [Citation(s) in RCA: 91] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
1. In premature fetal sheep (89-93 days gestation) we examined the fetal response to asphyxia induced by 30 min of complete umbilical cord occlusion. Fetuses were also studied during the first 3 days after asphyxia. We measured heart rate, blood pressure, carotid and femoral blood flows, vascular resistance, electroencephalographic activity and cerebral changes in haemoglobin concentration by near infrared spectroscopy (NIRS). 2. Fetuses tolerated 30 min of asphyxia and the cardiovascular response was characterized by three phases: initial redistribution of blood flow away from the periphery to maintain vital organ function, partial failure of this redistribution and near terminal cardiovascular collapse, with profound hypotension and cerebral and peripheral hypoperfusion. 3. Post-asphyxia carotid blood flow and NIRS data demonstrated that between 3-5 h there was a significant secondary reduction in cerebral blood flow, blood volume and oxygenation despite normal perfusion pressure and heart rate. There was also a secondary fall in femoral blood flow which persisted throughout recovery. 4. These data demonstrate that the immature fetus can survive a prolonged period of asphyxia, but paradoxically the capacity to survive exposes the fetus to profound hypotension and hypoperfusion. A secondary period of significant cerebral hypoperfusion and reduced oxygen delivery also occurred post-asphyxia. These cardiovascular and cerebrovascular responses may contribute to the patterns of cerebral injury seen in the human preterm fetus.
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Affiliation(s)
- L Bennet
- Research Centre for Developmental Medicine and Biology, Department of Paediatrics, The University of Auckland, Private Bag 92019, Auckland, New Zealand.
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Pourcyrous M, Bada HS, Yang W, Parfenova H, Wong SP, Korones SB, Leffler CW. Prognostic significance of cerebrospinal fluid cyclic adenosine monophosphate in neonatal asphyxia. J Pediatr 1999; 134:90-6. [PMID: 9880455 DOI: 10.1016/s0022-3476(99)70377-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
OBJECTIVE In piglets prolonged asphyxia resulted in decreased cerebrospinal fluid (CSF) 3;,5;-cyclic adenosine monophosphate (cAMP) during recovery; this was associated with reduced pial arteriolar responses to stimuli that use cAMP as a second messenger. We hypothesized that asphyxia in human neonates results in decreased CSF cAMP and that low CSF cAMP is associated with abnormal outcome. DESIGN We studied 27 infants with evidence of hypoxic-ischemic insult; 19 were term (group 1) and 8 were preterm (group 2). The normal values of CSF cAMP were determined from 75 infants with no asphyxia; 44 were term (group 3) and 31 were preterm (group 4). CSF cAMP was measured by using radioimmunoassay procedures. RESULTS CSF cAMP levels in infants with asphyxia (groups 1 and 2) were 12 +/- 9. 5 and 7.9 +/- 7.1 pmol/mL, respectively, significantly lower than those of groups 3 and 4 (control infants), that is, 21.1 +/- 8.7 and 27.1 +/- 9.2 pmol/mL, respectively (P <.0001). Among infants with asphyxia, 3 died and 10 had abnormal neurologic outcome. Univariate analysis showed that abnormal outcomes were significantly related to CSF cAMP levels, phenobarbital use, and multi-organ failure. However, only CSF cAMP was retained in the model by stepwise logistic regression. CSF cAMP of 10.0 pmol/mL discriminated between those with normal and those with abnormal neurologic outcome. Low CSF cAMP concentration was associated with abnormal long-term outcome, estimated odds ratio of 12.4 (95% CI, 2.1-109.3; P <.006), and sensitivity, specificity, and positive and negative predictive values of 85%, 69%, 73%, and 80%, respectively. CONCLUSION CSF cAMP concentrations were decreased in infants with asphyxia. Low CSF cAMP levels were associated with poor neurologic outcome.
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Affiliation(s)
- M Pourcyrous
- Laboratory for Research in Neonatal Physiology, Department of Pediatrics, The University of Tennessee, Memphis, USA
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Shadid M, Moison R, Steendijk P, Hiltermann L, Berger HM, van Bel F. The effect of antioxidative combination therapy on post hypoxic-ischemic perfusion, metabolism, and electrical activity of the newborn brain. Pediatr Res 1998; 44:119-24. [PMID: 9667381 DOI: 10.1203/00006450-199807000-00019] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Reoxygenation and reperfusion after severe hypoxia and ischemia (HI) contribute substantially to birth asphyxia-related brain injury. Excess production of free radicals via metabolization of arachidonic acid, xanthine oxidase, and non-protein-bound iron play an important role. Cerebral reperfusion injury is characterized by a decrease in perfusion, oxygen consumption, and electrical activity of the brain. Reduction of free radical production may attenuate these features. We therefore induced severe HI in 35 newborn lambs, and upon reperfusion the lambs received a placebo [control (CONT), n = 7], the cyclooxygenase inhibitor indomethacin (INDO, 0.3 mg/kg/i.v., n = 7), the xanthine oxidase inhibitor allopurinol (ALLO, 20 mg/kg/i.v., n = 7), the iron chelator deferoxamine (DFO, 2.5 mg/kg/i.v., n = 7), or a combination of these drugs (COMB, n = 7). In each group changes (%) from pre-HI values were investigated for brain perfusion [measured by carotid artery flow (Qcar, mL/min)], (relative) cerebral O2 metabolism (CMR(O2)), and electrocortical brain activity (ECBA, microV) at 15, 60, 120, and 180 min post-HI. Qcar decreased significantly at 120 and 180 min post-HI in CONT (p < 0.05), but not in INDO, ALLO, DFO, and COMB groups. CMR(O2) decreased significantly in CONT at 60 min post-HI (p < 0.05), remained stable in DFO and INDO, and was significantly higher in ALLO and COMB (p < 0.05) at 120 and 180 min post-HI. ECBA was significantly lower in CONT during the whole post-HI period (p < 0.05), ECBA in INDO and COMB were significantly decreased at 60 and 120 min post-HI (p < 0.05), but recovered afterward, whereas DFO and ALLO remained stable during the post-HI period. In conclusion preservation of Qcar and CMR(O2), and recovery of ECBA occurred after treatment with INDO, ALLO, and DFO; combination of these drugs did not have an additional positive effect.
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Affiliation(s)
- M Shadid
- Department of Pediatrics, Leiden University Hospital, The Netherlands
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Van Bel F, Shadid M, Moison RM, Dorrepaal CA, Fontijn J, Monteiro L, Van De Bor M, Berger HM. Effect of allopurinol on postasphyxial free radical formation, cerebral hemodynamics, and electrical brain activity. Pediatrics 1998; 101:185-93. [PMID: 9445490 DOI: 10.1542/peds.101.2.185] [Citation(s) in RCA: 139] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
OBJECTIVE Free radical-induced postasphyxial reperfusion injury has been recognized as an important cause of brain tissue damage. We investigated the effect of high-dose allopurinol (ALLO; 40 mg/kg), a xanthine-oxidase inhibitor and free radical scavenger, on free radical status in severely asphyxiated newborns and on postasphyxial cerebral perfusion and electrical brain activity. METHODS Free radical status was assessed by serial plasma determination of nonprotein-bound iron (microM), antioxidative capacity, and malondialdehyde (MDA; microM). Cerebral perfusion was investigated by monitoring changes in cerebral blood volume (delta CBV; mL/100 g brain tissue) with near infrared spectroscopy; electrocortical brain activity (ECBA) was assessed in microvolts by cerebral function monitor. Eleven infants received 40 mg/kg ALLO intravenously, and 11 infants served as controls (CONT). Plasma nonprotein-bound iron, antioxidative capacity, and MDA were measured before 4 hours, between 16 and 20 hours, and at the second and third days of age. Changes in CBV and ECBA were monitored between 4 and 8, 16 and 20, 58 and 62, and 104 and 110 hours of age. RESULTS Six CONT and two ALLO infants died after neurologic deterioration. No toxic side effects of ALLO were detected. Nonprotein-bound iron (mean +/- SEM) in the CONT group showed an initial rise (18.7 +/- 4.6 microM to 21.3 +/- 3.4 microM) but dropped to 7.4 +/- 3.5 microM at day 3; in the ALLO group it dropped from 15.5 +/- 4.6 microM to 0 microM at day 3. Uric acid was significantly lower in ALLO-treated infants from 16 hours of life on. MDA remained stable in the ALLO group, but increased in the CONT group at 8 to 16 hours versus < 4 hours (mean +/- SEM; 0.83 +/- 0.31 microM vs 0.50 +/- 0.14 microM). During 4 to 8 hours, delta CBV-CONT showed a larger drop than delta CBV-ALLO from baseline. During the subsequent registrations CBV remained stable in both groups. ECBA-CONT decreased, but ECBA-ALLO remained stable during 4 to 8 hours of age. Neonates who died had the largest drops in CBV and ECBA. CONCLUSION This study suggests a beneficial effect of ALLO treatment on free radical formation, CBV, and electrical brain activity, without toxic side effects.
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Affiliation(s)
- F Van Bel
- Department of Pediatrics, Leiden University Hospital, The Netherlands
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