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Jiang ZD, Wang C, Jiang JK. Postnatal functional integrity of the brainstem auditory pathway in late preterm infants born of small-for-gestation age: how different from those born of appropriate-for-gestation. Eur J Pediatr 2024; 183:3041-3051. [PMID: 38652266 DOI: 10.1007/s00431-024-05571-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Revised: 04/11/2024] [Accepted: 04/13/2024] [Indexed: 04/25/2024]
Abstract
It is unclear whether there is any postnatal abnormality in brainstem auditory function in late preterm small-for-gestational-age (SGA) infants. We investigated the functional integrity of the brainstem auditory pathway at 4 months after term in late preterm SGA infants and defined differences from appropriate-for-gestational age (AGA) infants. The maximum length sequence brainstem evoked response (MLS BAER) was recorded and analyzed in 24 SGA (birthweight < 3rd centile) infants and 28 AGA infants (birthweight > 10th centile). All infants were born at 33-36-week gestation without major perinatal and postnatal problems. We found that I-V interval in SGA infants was shorter than in AGA infants at higher click rates and significantly shorter at the highest rate of 910/s. Of the two smaller intervals, I-III interval was significantly shorter in SGA infants than in AGA infants at higher click rates of 455 and 910/s clicks, whereas III-V interval was similar in the two groups. The III-V/I-III interval ratio in SGA infants tended to be greater than in AGA infants at all rates and was significantly greater at 455 and 910/s clicks. The slope of I-III interval-rate functions in SGA infants was moderately smaller than in AGA infants. Conclusions: The main and fundamental difference between late preterm SGA and AGA infants was a significant shortening in the MLS BAER I-III interval in SGA infants at higher click rates, suggesting moderately faster neural conduction in the caudal brainstem regions. Postnatal neural maturation in the caudal brainstem regions is moderately accelerated in late preterm SGA infants. What is Known: • At 40 weeks of postconceptional age, late preterm SGA infants manifested a mild delay in neural conduction in the auditory brainstem. What is New: • At 56 weeks of postconceptional age, late preterm SGA infants manifested moderately faster neural conduction in the caudal brainstem regions. • Postnatal neural maturation is moderately accelerated in the caudal brainstem regions of late preterm SGA infants.
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Affiliation(s)
- Ze Dong Jiang
- Division of Neonatology, Children's Hospital of Fudan University, 399 Wan Yuan Road, Shanghai, 201112, China.
| | - Cui Wang
- Division of Neonatology, Children's Hospital of Fudan University, 399 Wan Yuan Road, Shanghai, 201112, China
| | - James K Jiang
- Division of Neonatology, Children's Hospital of Fudan University, 399 Wan Yuan Road, Shanghai, 201112, China
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Jiang ZD, Wang C, Ping LL, Yin R. Altered maturation in brainstem neural conduction in very premature babies with fetal growth restriction. Pediatr Res 2023; 94:1472-1479. [PMID: 36966269 DOI: 10.1038/s41390-023-02565-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Revised: 01/31/2023] [Accepted: 02/27/2023] [Indexed: 03/27/2023]
Abstract
BACKGROUND Using maximum length sequence brainstem auditory evoked response (MLS BAER) to study brainstem neural conduction and maturation in fetal growth restriction (FGR) babies born very prematurely and assess the effect of FGR on brainstem neural maturation. METHODS MLS BAER was recorded and analyzed at a mean 40 week postmenstrual age in babies born at 27-32 week gestation without other major perinatal conditions or problems. The data were compared between babies with FGR (n = 30) and age-matched babies without FGR (n = 34) to define any differences. RESULTS A notable difference in MLS BAER was found in interpeak intervals between the babies with FGR and those without FGR. The FGR babies manifested significantly shortened I-III interval, moderately prolonged III-V interval, and significantly decreased III-V/I-III interval ratio. The slope of the I-III interval-rate function in FGR babies was moderately decreased, relative to that in the babies without FGR. CONCLUSION FGR babies born very prematurely are associated with accelerated or precocial neural maturation at caudal brainstem regions, but moderately delayed maturation at rostral brainstem regions. The altered brainstem neural maturation is different from previously reported mildly delayed maturation in FGR babies born less prematurely, and may have important implication for neurodevelopmental outcome. IMPACT This first MLS BAER study in FGR found that brainstem neural maturation in very premature FGR babies differed from age-matched non-FGR babies. Neural maturation in very premature FGR babies is accelerated or precocial at caudal brainstem regions but moderately delayed at rostral brainstem regions. The altered maturation is different from previously reported mild delay in brainstem neural maturation in FGR babies born less prematurely. FGR exerts a major and differential effect on brainstem neural maturation in babies born very prematurely. This alteration in very premature FGR babies may have important implication for their neurodevelopment.
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Affiliation(s)
- Ze Dong Jiang
- Division of Neonatology, Children's Hospital of Fudan University, Shanghai, China.
| | - Cui Wang
- Division of Neonatology, Children's Hospital of Fudan University, Shanghai, China
| | - Li Li Ping
- Division of Neonatology, Children's Hospital of Fudan University, Shanghai, China
| | - Rong Yin
- Division of Neonatology, Children's Hospital of Fudan University, Shanghai, China
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Van Ginneken C, Ayuso M, Van Bockstal L, Van Cruchten S. Preweaning performance in intrauterine growth-restricted piglets: Characteristics and interventions. Mol Reprod Dev 2023; 90:697-707. [PMID: 35652465 DOI: 10.1002/mrd.23614] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2022] [Revised: 05/06/2022] [Accepted: 05/23/2022] [Indexed: 11/06/2022]
Abstract
Intrauterine growth restriction (IUGR) is frequently observed in pig production, especially when using highly prolific sows. IUGR piglets are born with low body weight and shape indicative of differences in organ growth. Insufficient uteroplacental nutrient transfer to the fetuses is the leading cause of growth restriction in the pig. Supplementing the sow's gestation diet with arginine and/or glutamine improves placenta growth and functionality and consequently is able to reduce IUGR incidence. IUGR piglets are at higher risk of dying preweaning and face higher morbidity than their normal-weight littermates. A high level of surveillance during farrowing and individual nutrient supplementation can reduce the mortality rates. Still, these do not reverse the long-term consequences of IUGR, which are induced by persistent structural deficits in different organs. Dietary interventions peri-weaning can optimize performance but these are less effective in combating the metabolic changes that occurred in IUGR, which affect reproductive performance later in life. IUGR piglets share many similarities with IUGR infants, such as a poorer outcome of males. Using the IUGR piglet as an animal model to further explore the structural and molecular basis of the long-term consequences of IUGR and the potential sex bias could aid in fully understanding the impact of prenatal undernutrition and finding solutions for both species and sexes.
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Affiliation(s)
- Chris Van Ginneken
- Comparative Perinatal Development (CoPeD), Faculty of Pharmaceutical, Biomedical and Veterinary Sciences, University of Antwerp, Antwerp, Belgium
| | - Miriam Ayuso
- Comparative Perinatal Development (CoPeD), Faculty of Pharmaceutical, Biomedical and Veterinary Sciences, University of Antwerp, Antwerp, Belgium
| | - Lieselotte Van Bockstal
- Comparative Perinatal Development (CoPeD), Faculty of Pharmaceutical, Biomedical and Veterinary Sciences, University of Antwerp, Antwerp, Belgium
| | - Steven Van Cruchten
- Comparative Perinatal Development (CoPeD), Faculty of Pharmaceutical, Biomedical and Veterinary Sciences, University of Antwerp, Antwerp, Belgium
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Cohen E, Baerts W, van Bel F. Brain-Sparing in Intrauterine Growth Restriction: Considerations for the Neonatologist. Neonatology 2015; 108:269-76. [PMID: 26330337 DOI: 10.1159/000438451] [Citation(s) in RCA: 89] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2015] [Accepted: 07/07/2015] [Indexed: 11/19/2022]
Abstract
Intrauterine growth restriction (IUGR) is most commonly caused by placental insufficiency, in response to which the fetus adapts its circulation to preserve oxygen and nutrient supply to the brain ('brain-sparing'). Currently, little is known about the postnatal course and consequences of this antenatal adaptation of the cerebral circulation. The altered cerebral haemodynamics may persist after birth, which would imply a different approach with regard to cerebral monitoring and clinical management of IUGR preterm neonates than their appropriately grown peers. Few studies are available with regard to this topic, and the small body of evidence shows controversy. This review discusses the cerebral circulatory adaptations of IUGR fetuses and appraises the available literature on their postnatal cerebral circulation with potential clinical consequences.
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Affiliation(s)
- Emily Cohen
- Department of Neonatology, Wilhelmina Children's Hospital/Utrecht University Medical Centre, Utrecht, The Netherlands
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Walter B, Eiselt M, Cumming P, Xiong G, Hinz R, Uthe S, Brust P, Bauer R. Resistance of brain glucose metabolism to thiopental-induced CNS depression in newborn piglets. Int J Dev Neurosci 2013; 31:157-64. [PMID: 23305916 DOI: 10.1016/j.ijdevneu.2012.12.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2012] [Accepted: 12/30/2012] [Indexed: 10/27/2022] Open
Abstract
The transition from mild sedation to deep anaesthesia is marked by the phenomenon of burst suppression (BS). FDG-PET studies show that the cerebral metabolic rate for glucose (CMRglc) declines dramatically with onset of BS in the adult brain. Global CMRglc increases substantially in the post-natal period and achieves its maximum in preadolescence. However, the impact of post-natal brain development on the vulnerability of CMRglc to the onset of BS has not been documented. Therefore, cerebral blood flow and metabolism were measured using a variant of the Kety-Schmidt method, in conjunction with quantitative regional estimation of brain glucose uptake by FDG-PET in groups of neonate and juvenile pigs, under a condition of light sedation or after induction of deep anaesthesia with thiopental. Quantification of simultaneous ECoG recordings was used to establish the correlation between anaesthesia-related changes in brain electrical activity and the observed cerebrometabolic changes. In the condition of light sedation the magnitude of CMRglc was approximately 20% higher in the older pigs, with the greatest developmental increase evident in the cerebral cortex and basal ganglia (P<0.05). Onset of BS was associated with 20-40% declines in CMRglc. Subtraction of the mean parametric maps for CMRglc showed the absolute reductions in CMRglc evoked by thiopental anaesthesia to be two-fold greater in the pre-adolescent pigs than in the neonates (P<0.05). Thus, the lesser suppression of brain energy demand of neonate brain during deep anaesthesia represents a reduced part of thiopental suppressing brain metabolism in neonates.
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Affiliation(s)
- Bernd Walter
- Institute of Molecular Cell Biology, Jena University Hospital, Friedrich Schiller University, Jena, Germany
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van Wassenaer AG, Westera J, van Schie PE, Houtzager BA, Cranendonk A, de Groot L, Ganzevoort W, Wolf H, de Vries JI. Outcome at 4.5 years of children born after expectant management of early-onset hypertensive disorders of pregnancy. Am J Obstet Gynecol 2011; 204:510.e1-9. [PMID: 21459356 DOI: 10.1016/j.ajog.2011.02.032] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2010] [Revised: 12/03/2010] [Accepted: 02/09/2011] [Indexed: 10/18/2022]
Abstract
OBJECTIVE The objective of the study was to describe neurodevelopmental outcome at the age of 4.5 years in 216 children, born after expectant management of severe early-onset hypertensive complications of pregnancy. STUDY DESIGN This was a prospective follow-up study until age 4.5 years from maternal admission onward. Developmental outcome measurements included child intelligence quotient and behavioral, motor, and neurological outcome. Abnormal composite outcome (perinatal mortality or abnormal developmental outcome) was studied in relation to gestational age (GA), birthweight (BW), and perinatal variables. RESULTS Fetal and neonatal mortality was 9% and 8%, respectively. Of the 178 survivors, 149 (84%) were seen for follow-up. Mean GA was 31.4 weeks and 90% were born growth restricted. Abnormal developmental outcome occurred in 20% and abnormal composite outcome in 37%. CONCLUSION Perinatal mortality or abnormal child development occurs in one third of pregnancies with early-onset and severe hypertensive complications and is highest in the lowest GA and BW ranges.
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Age-dependent effects of gradual decreases in cerebral perfusion pressure on the neurochemical response in swine. Intensive Care Med 2010; 36:1067-75. [PMID: 20232040 DOI: 10.1007/s00134-010-1846-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2009] [Accepted: 12/12/2009] [Indexed: 10/19/2022]
Abstract
OBJECTIVE There is still a lack of knowledge on the age-dependent relation between a reduction in cerebral perfusion pressure (CPP) and compromised brain perfusion leading to excessive transmitter release and brain damage cascades. The hypothesis is that an age-dependent lower threshold of cerebral blood flow (CBF) autoregulation determines the amount and time course of transmitter accumulation. DESIGN AND SETTING This was a prospective randomized, blinded animal study performed in a university laboratory involving eight newborn and 11 juvenile anesthetized pigs. INTERVENTION Striatal dopamine, glutamate, glucose, and lactate were monitored by microdialysis. For CPP manipulation, the cisterna magna was infused with artificial cerebrospinal fluid to control intracranial pressure at the maintained arterial blood pressure (stepwise CPP decrease in 15-min stages to 50, 40, 30, and finally 0 mmHg). MEASUREMENTS AND MAIN RESULTS Juvenile pigs showed a gradual decrease in CBF between 50 mmHg CPP (CPP-50) and 30 mmHg CPP (CPP-30), but a significant CBF reduction did not occur in newborn piglets until CPP-30 (P < 0.05). At CPP-30, brain oxidative metabolism was reduced only in juveniles, concomitantly with elevations in dopamine and glutamate levels (P < 0.05). In contrast, newborn piglets exhibited a delayed and blunted accumulated of transmitters and metabolites (P < 0.05). CONCLUSIONS The lower limit of CBF autoregulation was associated with modifications in neurochemical parameters that clearly occurred before brain oxidative metabolism was compromised. Early indicators for mild to moderate hypoperfusion are elevated levels of lactate and dopamine, but elevated levels of glutamate appear to be an indicator of brain ischemia. The shift to the left of the lower autoregulatory threshold is mainly responsible for the postponed neurochemical response to decrements in the CPP in the immature brain.
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Bauer R, Walter B, Brandl U. Intrauterine growth restriction improves cerebral O2 utilization during hypercapnic hypoxia in newborn piglets. J Physiol 2007; 584:693-704. [PMID: 17717008 PMCID: PMC2277152 DOI: 10.1113/jphysiol.2007.142778] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Data are scant regarding the capacity of cerebrovascular regulation during asphyxia for prevention of brain oxygen deficit in intrauterine growth-restricted (IUGR) newborns. We tested the hypothesis that IUGR improves the ability of neonates to withstand critical periods of severe asphyxia by optimizing brain oxygen supply. Studies were conducted to examine the effects of IUGR on cerebral blood flow (CBF) regulation and oxygen consumption (cerebral metabolic rate for oxygen, CMRO(2)) at different stages of asphyxia (hypercapnic hypoxaemia) in comparison to pure hypoxia (normocapnic hypoxaemia). We used 1-day-old anaesthetized and ventilated piglets. Animals were divided into normal weight (NW) piglets (n = 47; aged 11-26 h, body weight 1481 +/- 121 g) and IUGR piglets (n = 48; aged 13-28 h, body weight 806 +/- 42 g) according to their birth weight. Different stages of hypoxaemia were induced for 1 h by appropriate lowering of the inspired fraction of oxygen (moderate hypoxia: = 31-34 mmHg; severe hypoxia: = 20-22 mmHg). Fourteen NW and 16 IUGR piglets received additionally 9% CO(2) in the breathing gas, so that a of 74-80 mmHg resulted (hypoxia/hypercapnia groups). Eight NW and nine IUGR animals served as untreated controls. Furthermore, affinity of haemoglobin for oxygen was measured under hypoxic and asphyxic conditions. During asphyxia cerebral oxygen extraction was markedly increased in IUGR animals (P < 0.05). This resulted in a significantly diminished CMRO(2)-related increase of CBF at gradually reduced arterial oxygen content (P < 0.05). Therefore, an enhanced effectivity in oxygen availability appeared in newborn IUGR piglets under graded asphyxia by improved cerebral oxygen utilization (P < 0.05). This was not supported by related O(2) affinity of haemoglobin. Thus, IUGR newborns are more capable to ensure brain O(2) demand during asphyxia (hypercapnic hypoxia) than NW neonates.
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Affiliation(s)
- Reinhard Bauer
- Institute of Molecular Cell Biology, Center for Molecular Biomedicine, and Department of Neuropaediatrics, Children's Hospital, Friedrich Schiller University, D-07740 Jena, Germany.
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Jelsing J, Gundersen HJG, Nielsen R, Hemmingsen R, Pakkenberg B. The postnatal development of cerebellar Purkinje cells in the Göttingen minipig estimated with a new stereological sampling technique--the vertical bar fractionator. J Anat 2007; 209:321-31. [PMID: 16928201 PMCID: PMC2100328 DOI: 10.1111/j.1469-7580.2006.00611.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
The postnatal development of total number and perikaryon volume of cerebellar Purkinje cells was estimated in the Göttingen minipig cerebellar cortex using a new stereological approach, the vertical bar fractionator. Data were obtained from the brains of five neonate and five adult female Göttingen minipigs. The total number of Purkinje cells ranged from 1.83 x 10(6) in the neonate to 2.82 x 10(6) in the adult Göttingen minipig. The number-weighted mean perikaryon volume of Purkinje cells increased concurrently from around 6,800 microm(3) in the neonate to 17,600 microm(3) in the adult. The study demonstrates that a pronounced postnatal neurogenesis in Purkinje cell number and perikaryon volume is part of the growth and development of the cerebellum in the Göttingen minipig. The Purkinje cells of the Göttingen minipig were found to be substantially large compared with human and represents the largest cells described hitherto from mammalian cerebella. The vertical fractionator is a new sampling technique, which allows the combination of a fractionator design on vertical bar sections excluding exhaustive sampling and bias from artificial edges. By design, the sections are perfect stereological vertical sections and provide the basis for unbiased estimates of total number of structural entities in the brain, including surface area, fibre length and particle volume.
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Affiliation(s)
- Jacob Jelsing
- Research Laboratory for Stereology and Neuroscience, Copenhagen University Hospital, Bispebjerg, Copenhagen, Denmark.
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Duhaime AC. Large animal models of traumatic injury to the immature brain. Dev Neurosci 2006; 28:380-7. [PMID: 16943661 DOI: 10.1159/000094164] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2005] [Accepted: 05/09/2006] [Indexed: 11/19/2022] Open
Abstract
Large animal models have been used much less frequently than rodent models to study traumatic brain injury. However, large animal models offer distinct advantages in replicating specific mechanisms, morphology and maturational stages relevant to age-dependent injury responses. This paper reviews how each of these features is relevant in matching a model to a particular scientific question and discusses various scaling strategies, advantages and disadvantages of large animal models for studying traumatic brain injury in infants and children. Progress to date and future directions are outlined.
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Affiliation(s)
- Ann-Christine Duhaime
- Pediatric Neurosurgery, Children's Hospital at Dartmouth, Dartmouth Hitchcock Medical Center, Lebanon, NH 03756, USA.
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Bauer R, Gedrange T, Bauer K, Walter B. Intrauterine growth restriction induces increased capillary density and accelerated type I fiber maturation in newborn pig skeletal muscles. J Perinat Med 2006; 34:235-42. [PMID: 16602845 DOI: 10.1515/jpm.2006.042] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
AIMS Humans with low birth weight exhibit evidences of vascular dysfunction. Recent findings indicate a microvascular rarefaction in skeletal muscles soon after postnatal development in rats suffered by intrauterine protein restriction. METHODS To examine the effects of intrauterine growth restriction on capillary density, muscle fiber distribution and accompanying muscular and systemic circulation immediately after birth, studies were conducted on 1-day-old anesthetized normal weight (n = 7) and intrauterine growth restricted (n = 6) piglets. Cardiac output and hind limb muscle blood flow were measured by colored microspheres. Counting of type I fibers and skeletal capillary numbers was done by immunohistochemical staining. RESULTS Increased proportion of type I fibers and capillary density was found in the flexor digitalis superficialis and gastrocnemius medialis (P < 0.05) in newborn IUGR piglets. Furthermore, a marked correlation was shown between capillary density and type I fiber fraction for all flexor muscles studied (P < 0.05). Moreover, cardiac output and muscular blood flow were markedly increased in IUGR piglets (P < 0.05). Correspondingly, total peripheral resistance, as well as vascular resistance, of hind limb flexors appeared significantly decreased (P < 0.05). CONCLUSIONS Compromised intrauterine environmental conditions leading to fetal growth restriction provokes coordinated structural and functional adaptation of skeletal muscles.
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Affiliation(s)
- Reinhard Bauer
- Institute for Molecular Cell Biology, Pathophysiology Lab, Friedrich Schiller University, Jena, Germany.
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Vallet JL, Freking BA. Changes in fetal organ weights during gestation after selection for ovulation rate and uterine capacity in swine1,2. J Anim Sci 2006; 84:2338-45. [PMID: 16908635 DOI: 10.2527/jas.2006-083] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
We hypothesized that the ability of the fetus to alter nutrient shunting and organ growth might be associated with uterine capacity. White crossbred gilts from a randomly selected control line, a line selected for ovulation rate, and a line selected for uterine capacity (UC) were unilaterally hysterectomized-ovariectomized at 160 d of age, mated at estrus, and slaughtered at 45, 65, 85, and 105 d of gestation (9 to 18 gilts for each line x day combination). Analysis of the data revealed that heart weights and fetal weights were decreased in the ovulation rate line. No significant differences were obtained in fetal, placental, or fetal organ weights between the control and UC lines. Allometric growth of organs was assessed by examination of the slopes of the relationships between fetal weights and fetal organ weights after natural log transformation. Only the relative growth of the liver differed between selection lines and was greater (P = 0.01) in the UC compared with the control line during early pregnancy (d 45 and 65). Allometric growth of the fetal brain, liver, and heart differed with day of gestation. A brain-sparing effect was greater (P < 0.01) on d 85 and 105 compared with d 45 and 65. By contrast, a heart-sparing effect was present during early gestation and disappeared in later gestation. Fetal liver weights were hypersensitive to differences in fetal weights on d 45, possibly associated with placental effects on fetal liver weight. Fetal spleen weights were proportional to fetal weights throughout gestation. These results indicate that selection for ovulation rate decreased total fetal and fetal heart weights, and that selection for UC altered the relationship between total fetal and fetal liver weights during early gestation. Results further indicate significant changes in allometric growth of organs during gestation.
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Affiliation(s)
- J L Vallet
- USDA, ARS, US Meat Animal Research Center, P.O. Box 166, Clay Center, NE 68933, USA.
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Bauer R, Walter B, Vorwieger G, Fritz A, Füchtner F, Zwiener U, Brust P. Effect of moderate hypercapnic hypoxia on cerebral dopaminergic activity and brain O2 uptake in intrauterine growth-restricted newborn piglets. Pediatr Res 2005; 57:363-70. [PMID: 15611347 DOI: 10.1203/01.pdr.0000150800.19956.f0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
There is evidence that intrauterine growth restriction (IUGR) is associated with altered dopaminergic function in the immature brain. Compelling evidence exists that in the newborn brain, specific structures are especially vulnerable to O2 deprivation. The dopaminergic system is shown to be sensitive to O2 deprivation in the immature brain. However, the respective enzyme activities have not been measured in the living neonatal brain after IUGR under hypercapnic hypoxia (H/H). Therefore, 18F-labeled 6-fluoro-L-3,4-dihydroxyphenylalanine (FDOPA) together with positron emission tomography was used to estimate the aromatic amino acid decarboxylase activity of the brain of seven normal weight (body weight 2078 +/- 434 g) and seven IUGR newborn piglets (body weight 893 +/- 109 g). Two positron emission tomography scans were performed in each piglet. All animals underwent a period of normoxia and moderate H/H. Simultaneously, cerebral blood flow was measured with colored microspheres and cerebral metabolic rate of O2 was determined. In newborn normal-weight piglets, the rate constant for FDOPA decarboxylation was markedly increased in mesostriatal regions during H/H, whereas brain oxidative metabolism remained unaltered. In contrast, moderate H/H induced in IUGR piglets a marked reduction of clearance rates for FDOPA metabolites (p <0.05), which was accompanied by a tendency of lowering the rate constant for FDOPA conversion. Furthermore, IUGR piglets maintained cerebral O2 uptake in the early period of H/H, but during the late period of H/H, a significantly reduced cerebral metabolic rate of O2 occurred (p <0.05). Thus, IUGR is accompanied by a missing activation of dopaminergic activity and attenuated brain oxidative metabolism during moderate H/H. This may indicate endogenous brain protection against O2 deprivation.
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Affiliation(s)
- Reinhard Bauer
- Institute of Pathophysiology and Pathobiochemistry, Universitätsklinikum Jena, Friedrich Schiller University, D-07740 Jena, Germany.
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