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Govaert P, Triulzi F, Dudink J. The developing brain by trimester. HANDBOOK OF CLINICAL NEUROLOGY 2020; 171:245-289. [PMID: 32736754 DOI: 10.1016/b978-0-444-64239-4.00014-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Transient anatomical entities play a role in the maturation of brain regions and early functional fetal networks. At the postmenstrual age of 7 weeks, major subdivisions of the brain are visible. At the end of the embryonic period, the cortical plate covers the neopallium. The choroid plexus develops in concert with it, and the dorsal thalamus covers about half the diencephalic third ventricle surface. In addition to the fourth ventricle neuroepithelium the rhombic lips are an active neuroepithelial production site. Early reciprocal connections between the thalamus and cortex are present. The corticospinal tract has reached the pyramidal decussation, and the arteries forming the mature circle of Willis are seen. Moreover, the superior sagittal sinus has formed, and at the rostral neuropore the massa commissuralis is growing. At the viable preterm age of around 24 weeks PMA, white matter tracts are in full development. Asymmetric progenitor division permits production of neurons, subventricular zone precursors, and glial cells. Myelin is present in the ventral spinal quadrant, cuneate fascicle, and spinal motor fibers. The neopallial mantle has been separated into transient layers (stratified transitional fields) between the neuroepithelium and the cortical plate. The subplate plays an important role in organizing the structuring of the cortical plate. Commissural tracts have shaped the corpus callosum, early primary gyri are present, and opercularization has started caudally, forming the lateral fissure. Thalamic and striatal nuclei have formed, although GABAergic neurons continue to migrate into the thalamus from the corpus gangliothalamicum. Near-term PMA cerebral sublobulation is active. Between 24 and 32 weeks, primary sulci develop. Myelin is present in the superior cerebellar peduncle, rubrospinal tract, and inferior olive. Germinal matrix disappears from the telencephalon, except for the GABAergic frontal cortical subventricular neuroepithelium.
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Affiliation(s)
- Paul Govaert
- Department of Neonatology, Erasmus University Medical Center, Rotterdam, The Netherlands; Department of Neonatology, ZNA Middelheim, Antwerp, Belgium; Department of Rehabilitation and Physical Therapy, Gent University Hospital, Gent, Belgium.
| | - Fabio Triulzi
- Department of Pediatric Neuroradiology, Università Degli Studi di Milano, Milan, Italy
| | - Jeroen Dudink
- Department of Neonatology, University Medical Center, Utrecht, The Netherlands
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Yarnykh VL, Prihod'ko IY, Savelov AA, Korostyshevskaya AM. Quantitative Assessment of Normal Fetal Brain Myelination Using Fast Macromolecular Proton Fraction Mapping. AJNR Am J Neuroradiol 2018; 39:1341-1348. [PMID: 29748201 DOI: 10.3174/ajnr.a5668] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Accepted: 03/23/2018] [Indexed: 01/08/2023]
Abstract
BACKGROUND AND PURPOSE Fast macromolecular proton fraction mapping is a recently emerged MRI method for quantitative myelin imaging. Our aim was to develop a clinically targeted technique for macromolecular proton fraction mapping of the fetal brain and test its capability to characterize normal prenatal myelination. MATERIALS AND METHODS This prospective study included 41 pregnant women (gestational age range, 18-38 weeks) without abnormal findings on fetal brain MR imaging performed for clinical indications. A fast fetal brain macromolecular proton fraction mapping protocol was implemented on a clinical 1.5T MR imaging scanner without software modifications and was performed after a clinical examination with an additional scan time of <5 minutes. 3D macromolecular proton fraction maps were reconstructed from magnetization transfer-weighted, T1-weighted, and proton density-weighted images by the single-point method. Mean macromolecular proton fraction in the brain stem, cerebellum, and thalamus and frontal, temporal, and occipital WM was compared between structures and pregnancy trimesters using analysis of variance. Gestational age dependence of the macromolecular proton fraction was assessed using the Pearson correlation coefficient (r). RESULTS The mean macromolecular proton fraction in the fetal brain structures varied between 2.3% and 4.3%, being 5-fold lower than macromolecular proton fraction in adult WM. The macromolecular proton fraction in the third trimester was higher compared with the second trimester in the brain stem, cerebellum, and thalamus. The highest macromolecular proton fraction was observed in the brain stem, followed by the thalamus, cerebellum, and cerebral WM. The macromolecular proton fraction in the brain stem, cerebellum, and thalamus strongly correlated with gestational age (r = 0.88, 0.80, and 0.73; P < .001). No significant correlations were found for cerebral WM regions. CONCLUSIONS Myelin is the main factor determining macromolecular proton fraction in brain tissues. Macromolecular proton fraction mapping is sensitive to the earliest stages of the fetal brain myelination and can be implemented in a clinical setting.
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Affiliation(s)
- V L Yarnykh
- From the Department of Radiology (V.L.Y.), University of Washington, Seattle, Washington .,Research Institute of Biology and Biophysics (V.L.Y.), Tomsk State University, Tomsk, Russian Federation
| | - I Y Prihod'ko
- Institute "International Tomography Center" of the Siberian Branch of the Russian Academy of Sciences (I.Y.P., A.A.S., A.M.K.), Novosibirsk, Russian Federation
| | - A A Savelov
- Institute "International Tomography Center" of the Siberian Branch of the Russian Academy of Sciences (I.Y.P., A.A.S., A.M.K.), Novosibirsk, Russian Federation
| | - A M Korostyshevskaya
- Institute "International Tomography Center" of the Siberian Branch of the Russian Academy of Sciences (I.Y.P., A.A.S., A.M.K.), Novosibirsk, Russian Federation
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Angiogenesis induced by prenatal ischemia predisposes to periventricular hemorrhage during postnatal mechanical ventilation. Pediatr Res 2015; 77:663-73. [PMID: 25665055 PMCID: PMC4405433 DOI: 10.1038/pr.2015.34] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/15/2014] [Accepted: 11/05/2014] [Indexed: 12/29/2022]
Abstract
BACKGROUND Three risk factors are associated with hemorrhagic forms of encephalopathy of prematurity (EP): (i) prematurity, (ii) in utero ischemia (IUI) or perinatal ischemia, and (iii) mechanical ventilation. We hypothesized that IUI would induce an angiogenic response marked by activation of vascular endothelial growth factor (VEGF) and matrix metalloproteinase-9 (MMP-9), the latter degrading vascular basement membrane and increasing vulnerability to raised intravenous pressure during positive pressure mechanical ventilation. METHODS We studied a rat model of hemorrhagic-EP characterized by periventricular hemorrhages in which a 20-min episode of IUI is induced at E19, pups are born naturally at E21-22, and on P0, are subjected to a 20-min episode of positive pressure mechanical ventilation. Tissues were studied by H&E staining, immunolabeling, immunoblot, and zymography. RESULTS Mechanical ventilation of rat pups 2-3 d after 20-min IUI caused widespread hemorrhages in periventricular tissues. IUI resulted in upregulation of VEGF and MMP-9. Zymography confirmed significantly elevated gelatinase activity. MMP-9 activation was accompanied by severe loss of MMP-9 substrates, collagen IV and laminin, in microvessels in periventricular areas. CONCLUSION Our findings are consistent with the hypothesis that positive pressure mechanical ventilation of the newborn in the context of recent prenatal ischemia/hypoxia can predispose to periventricular hemorrhages.
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Abstract
Intraventricular hemorrhage (IVH) is a major neurologic complication of prematurity. Pathogenesis of IVH is attributed to intrinsic fragility of germinal matrix vasculature and to the fluctuation in the cerebral blood flow. Germinal matrix exhibits rapid angiogenesis orchestrating formation of immature vessels. Prenatal glucocorticoid exposure remains the most effective means of preventing IVH. Therapies targeted to enhance the stability of the germinal matrix vasculature and minimize fluctuation in the cerebral blood flow might lead to more effective strategies in preventing IVH.
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Affiliation(s)
- Praveen Ballabh
- Department of Pediatrics, Cell Biology and Anatomy, Regional Neonatal Center, New York Medical College, Maria Fareri Children's Hospital, Westchester Medical Center, 100 Woods Road, Valhalla, NY 10595, USA.
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Raets MMA, Dudink J, Govaert P. Neonatal disorders of germinal matrix. J Matern Fetal Neonatal Med 2013; 28 Suppl 1:2286-90. [DOI: 10.3109/14767058.2013.796169] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Affiliation(s)
- Rebecca D Folkerth
- Department of Pathology, Brigham and Women's Hospital, and Harvard Medical School, Boston, MA 02130, USA.
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Iwasaki SI, Yoshizawa H, Aoyagi H. Localization of type III collagen in the lingual mucosa of rats during the morphogenesis of circumvallate papillae. Odontology 2011; 100:10-21. [PMID: 21556725 DOI: 10.1007/s10266-011-0020-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2009] [Accepted: 02/01/2011] [Indexed: 12/28/2022]
Abstract
In an effort to identify a possible role for type III collagen in the morphogenesis of circumvallate papillae on the surface of the rat tongue, we examined its appearance by fluorescent immunostaining, in conjunction with differential interference contrast images and images obtained, after staining with toluidine blue, in the transmission mode by laser-scanning microscopy. We analyzed semi-ultrathin sections of epoxy resin-embedded samples of the lingual mucosa of embryonic and juvenile rats, 13 days after conception (E13) to day 21 after birth (P21). Immunoreactivity specific for type III collagen was recognized first in the mesenchymal connective tissue just beneath the circumvallate papilla placode in fetuses on E13. At this stage, most of the lingual epithelium with the exception of the circumvallate papilla placode was pseudostratified epithelium composed of one or two layers of cuboidal cells. However, the epithelium of the circumvallate papilla placode was composed of several layers of cuboidal cells. Immunoreactivity specific for type III collagen was detected mainly on the lamina propria just beneath the lingual epithelium of the rudiment of the circumvallate papilla and the developing circumvallate papilla in fetuses on E15 and E17, and slight immunostaining was detected on the lamina propria around the rudiment. In fetuses on E19, immunoreactivity specific for type III collagen was widely and densely distributed on the connective tissue around the developing circumvallate papillae and, also, on the connective tissue that surrounded the lingual muscle. However, the immunoreactivity specific for type III collagen was sparsely distributed on the lamina propria of each central papillar structure. After birth, from P0 to P14, morphogenesis of the circumvallate papillae advanced gradually with the increase in the total volume of the tongue. At these postnatal stages, the intensity of the fluorescence due to immunoreactivity specific for type III collagen was distinctively distributed on the lamina propria around each circumvallate papilla, on each central bulge and on the connective tissue that surrounded the lingual muscle. However, immunofluorescence was less distinct on the connective tissue that surrounded the lingual muscle. Thus, type III collagen appeared in conjunction with the morphogenesis of the circumvallate papillae, as well as in the connective tissue that surrounded the lingual muscle during myogenesis of the rat tongue.
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Affiliation(s)
- Shin-ichi Iwasaki
- Advanced Research Center, The Nippon Dental University School of Life Dentistry at Niigata, 1-8 Hamaura-cho, Chuo-ku, Niigata, 951-8580, Japan.
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Abstract
Intraventricular hemorrhage (IVH) is a major complication of prematurity. IVH typically initiates in the germinal matrix, which is a richly vascularized collection of neuronal-glial precursor cells in the developing brain. The etiology of IVH is multifactorial and is primarily attributed to the intrinsic fragility of the germinal matrix vasculature and the disturbance in the cerebral blood flow (CBF). Although this review broadly describes the pathogenesis of IVH, the main focus is on the recent development in molecular mechanisms that elucidates the fragility of the germinal matrix vasculature. The microvasculature of the germinal matrix is frail because of an abundance of angiogenic blood vessels that exhibit paucity of pericytes, immaturity of basal lamina, and deficiency of glial fibrillary acidic protein (GFAP) in the ensheathing astrocytes endfeet. High VEGF and angiopoietin-2 levels activate a rapid angiogenesis in the germinal matrix. The elevation of these growth factors may be ascribed to a relative hypoxia of the germinal matrix perhaps resulting from high metabolic activity and oxygen consumption of the neural progenitor cells. Hence, the rapid stabilization of the angiogenic vessels and the restoration of normal CBF on the first day of life are potential strategies to prevent IVH in premature infants.
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Affiliation(s)
- Praveen Ballabh
- Department of Pediatrics, Anatomy and Cell Biology, New York Medical College-Westchester Medical Center, Valhalla, New York 10595, USA.
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Reduced ratio of afferent to total vascular density in mesial temporal sclerosis. J Neuropathol Exp Neurol 2009; 68:1147-54. [PMID: 19918126 DOI: 10.1097/nen.0b013e3181b9d75f] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Mesial temporal sclerosis (MTS) is the most common cause of drug-resistant temporal lobe epilepsy in adults. Despite nearly 2 centuries since the first reports of MTS, relatively little is known about its etiology and pathogenesis. Increasing attention has been directed toward the potential role of vascular abnormalities in MTS. We evaluated the hippocampal microvasculature in 9 MTS cases and 3 non-MTS controls using celloidin tissue sections and markers for total (collagen type IV) and afferent (enzymatic alkaline phosphatase) vessels. Tissue sections were assessed by light microscopy and quantified by threshold analysis of digital images and stereological analysis using the Space Balls probe. Although consistent alterations in the total microvascular density were not found, there was a significant reduction in the density of afferent vessels using both methodologies; these reductions were in areas CA2 and CA3 by image threshold analysis and in area CA3 using stereological measures of the ratio of afferent to total vessels. Increased numbers of string vessels (i.e. remnants of regressing vasculature) were also observed in Ammon's horn, suggesting vascular degeneration in the MTS hippocampus. These findings may help further our understanding of the pathophysiology of MTS.
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Immunohistochemical analysis of type III collagen expression in the lingual mucosa of rats during organogenesis of the tongue. Odontology 2008; 96:12-20. [DOI: 10.1007/s10266-008-0080-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2007] [Accepted: 12/10/2007] [Indexed: 11/26/2022]
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Xu H, Hu F, Sado Y, Ninomiya Y, Borza DB, Ungvari Z, Lagamma EF, Csiszar A, Nedergaard M, Ballabh P. Maturational changes in laminin, fibronectin, collagen IV, and perlecan in germinal matrix, cortex, and white matter and effect of betamethasone. J Neurosci Res 2008; 86:1482-500. [PMID: 18214989 DOI: 10.1002/jnr.21618] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Germinal matrix is selectively vulnerable to hemorrhage in premature infants, and use of prenatal betamethasone is associated with a lower occurrence of germinal matrix hemorrhage. Because the major components of extracellular matrix of the cerebral vasculature-laminin, fibronectin, collagen IV, and perlecan-provide structural stability to blood vessels, we examined whether the expression of these molecules was decreased in the germinal matrix and affected by betamethasone. In both human fetuses and premature infants, fibronectin was significantly lower in the germinal matrix than in the cortical mantle or white matter anlagen. Conversely, laminin alpha1 gene expression was greater in the human germinal matrix compared with the cortical mantle or white matter. Expression of alpha1- and alpha2(IV) collagen chains increased with advancing gestational age. Low-dose prenatal betamethasone treatment enhanced fibronectin level by 1.5-2-fold whereas a high dose reduced fibronectin expression by 2-fold in rabbit pups. Because fibronectin provides structural stability to the blood vessels, its reduced expression in the germinal matrix may contribute to the fragility of germinal matrix vasculature and the propensity to hemorrhage in premature neonates.
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Affiliation(s)
- Hongmin Xu
- Department of Pediatrics, New York Medical College-Westchester Medical Center, Valhalla, New York 10595, USA
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Braun A, Xu H, Hu F, Kocherlakota P, Siegel D, Chander P, Ungvari Z, Csiszar A, Nedergaard M, Ballabh P. Paucity of pericytes in germinal matrix vasculature of premature infants. J Neurosci 2007; 27:12012-24. [PMID: 17978043 PMCID: PMC6673365 DOI: 10.1523/jneurosci.3281-07.2007] [Citation(s) in RCA: 108] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2007] [Revised: 09/09/2007] [Accepted: 09/14/2007] [Indexed: 11/21/2022] Open
Abstract
Germinal matrix (GM) is a richly vascularized collection of neuronal-glial precursor cells in the developing brain, which is selectively vulnerable to hemorrhage in premature infants. It has rapid angiogenesis associated with high levels of vascular endothelial growth factor (VEGF). Because pericytes provide structural stability to blood vessels, we asked whether pericytes were fewer in the GM than in the subjacent white matter and neocortex and, if so, whether angiogenic inhibition could increase the pericyte density in the GM. We found pericyte coverage and density less in the GM vasculature than in the cortex or white matter in human fetuses, premature infants, and premature rabbit pups. Notably, although VEGF suppression significantly enhanced pericyte coverage in the GM, it remained less than in other brain regions. Therefore, to further elucidate the basis of fewer pericytes in the GM vasculature, we examined expression of ligand-receptor systems responsible for pericyte recruitment. Transforming growth factor-beta1 (TGF-beta1) protein expression was lower, whereas sphingosine-1-phosphate1 (S1P1) and N-cadherin levels were higher in the GM than in the cortex or white matter. Low TGF-beta1 may be involved in promoting endothelial proliferation, whereas elevated S1P1 with N-cadherin may assist vascular maturation. Hence, a paucity of pericytes in the GM vasculature may contribute to its propensity to hemorrhage, and a lower expression of TGF-beta1 could be a basis of reduced pericyte density in its vasculature.
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Affiliation(s)
| | | | | | | | | | | | - Zoltan Ungvari
- Physiology, New York Medical College, Westchester Medical Center, Valhalla, New York 10595, and
| | - Anna Csiszar
- Physiology, New York Medical College, Westchester Medical Center, Valhalla, New York 10595, and
| | - Maiken Nedergaard
- Neurosurgery and Center of Aging and Developmental Biology, University of Rochester, Rochester, New York 14642
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Anstrom JA, Thore CR, Moody DM, Brown WR. Immunolocalization of tight junction proteins in blood vessels in human germinal matrix and cortex. Histochem Cell Biol 2006; 127:205-13. [PMID: 16957815 DOI: 10.1007/s00418-006-0232-z] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/14/2006] [Indexed: 01/21/2023]
Abstract
Brain development occurs in a specialized environment maintained by a blood-brain barrier (BBB). An important structural element of the BBB is the endothelial tight junction (TJ). TJs are present during the embryonic period, but BBB impermeability accrues over an extended gestational interval. In studies of human premature infants, we used immunomicroscopy to determine if amounts of the TJ proteins ZO-1, claudin and occludin increase with gestational age in vessels of germinal matrix (GM) and cortex. By 24 weeks postconception (PC), TJ proteins were present in both GM and cortical vessels, but immunoreactivity in the GM of the youngest subjects was less than in older subjects. At 24 weeks PC, TJ protein immunoreactivity in GM vessels was less than in cortical vessels suggesting that TJ maturation progresses along a superficial to deep brain axis. This concept correlates with conclusions from previous analyses of the expression of brain endothelial cell alkaline phosphatase (AP) activity. AP appears in cortical vessels before appearing in deep white matter and GM vessels. Together, these data indicate that differentiation of some functional specializations is still in progress in GM vessels during the third trimester. This maturation could relate to the pathogenesis of germinal matrix hemorrhage-intraventricular hemorrhage.
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Affiliation(s)
- John A Anstrom
- Department of Radiology, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA,
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Hecht J, Kuhl H, Haas SA, Bauer S, Poustka AJ, Lienau J, Schell H, Stiege AC, Seitz V, Reinhardt R, Duda GN, Mundlos S, Robinson PN. Gene identification and analysis of transcripts differentially regulated in fracture healing by EST sequencing in the domestic sheep. BMC Genomics 2006; 7:172. [PMID: 16822315 PMCID: PMC1578570 DOI: 10.1186/1471-2164-7-172] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2006] [Accepted: 07/05/2006] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The sheep is an important model animal for testing novel fracture treatments and other medical applications. Despite these medical uses and the well known economic and cultural importance of the sheep, relatively little research has been performed into sheep genetics, and DNA sequences are available for only a small number of sheep genes. RESULTS In this work we have sequenced over 47 thousand expressed sequence tags (ESTs) from libraries developed from healing bone in a sheep model of fracture healing. These ESTs were clustered with the previously available 10 thousand sheep ESTs to a total of 19087 contigs with an average length of 603 nucleotides. We used the newly identified sequences to develop RT-PCR assays for 78 sheep genes and measured differential expression during the course of fracture healing between days 7 and 42 postfracture. All genes showed significant shifts at one or more time points. 23 of the genes were differentially expressed between postfracture days 7 and 10, which could reflect an important role for these genes for the initiation of osteogenesis. CONCLUSION The sequences we have identified in this work are a valuable resource for future studies on musculoskeletal healing and regeneration using sheep and represent an important head-start for genomic sequencing projects for Ovis aries, with partial or complete sequences being made available for over 5,800 previously unsequenced sheep genes.
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Affiliation(s)
- Jochen Hecht
- Max Planck Institute for Molecular Genetics, Berlin, Germany.
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Abstract
Animal models have assisted in understanding the mechanisms of brain injury underlying cerebral palsy. Nevertheless, no such models replicate every aspect of the human disease. This review summarizes the classic and more recent studies of the neuropathology of human perinatal brain injury most commonly associated with cerebral palsy, for use by researchers and clinicians alike who need to analyze published animal models with respect to their fidelity to the human disorder. The neuropathology underlying cerebral palsy includes white-matter injury, known as periventricular leukomalacia, as well as germinal matrix hemorrhage with intraventricular extension, and injury to the cortex, basal ganglia, and thalamus. Each has distinctive features while sharing some risk factors, such as prematurity and/or hypoxia-ischemia in the perinatal period. Periventricular leukomalacia consists of diffuse injury of deep cerebral white matter, with or without focal necrosis. Recent work directly in human postmortem tissue has focused on the role of free radical injury, cytokine toxicity (especially in light of the epidemiologic association of periventricular leukomalacia with maternofetal infection), and excitotoxicity in the development of periventricular leukomalacia. Premyelinating oligodendrocytes, which predominate in periventricular regions during the window of vulnerability to periventricular leukomalacia (24-34 postconceptional weeks), are the targets of free radical injury, as determined by immunocytochemical markers of lipid peroxidation and protein nitration. This maturational susceptibility can be attributed in part to a relative deficiency of superoxide dismutases in developing white matter. Microglia, which respond to cytokines and to bacterial products such as lipopolysaccharide via Toll-like receptors, are increased in periventricular leukomalacia white matter and can contribute to cellular damage. Indeed, several cytokines, including tumor necrosis factor-a and interleukins 2 and 6, as well as interferon-g, have been demonstrated in periventricular leukomalacia. Preliminary work suggests a role for glutamate receptors and glutamate transporters in periventricular leukomalacia based on expression in human developing oligodendrocytes. Germinal matrix hemorrhage, with or without intraventricular hemorrhage, occurs in premature infants and can coexist with periventricular leukomalacia. Studies in human germinal matrix tissue have focused on maturation-based vascular factors, such as morphometry and expression of molecules related to the structure of the blood-brain barrier. Gray-matter injury, seen more commonly in term infants, includes cortical infarcts and status marmoratus. Subtle cortical injury overlying periventricular leukomalacia is the subject of current interest as a possible substrate for the cognitive difficulties seen in patients with cerebral palsy. In summary, it is hoped that work in human tissue, in conjunction with experimental animal models, will lead to eventual therapeutic or preventive strategies for the perinatal brain injury underlying cerebral palsy.
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Affiliation(s)
- Rebecca D Folkerth
- Department of Pathology, Brigham and Women's Hospital, Children's Hospital, and Harvard Medical School, Boston, MA 02115, USA.
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Xue M, Balasubramaniam J, Parsons KAL, McIntyre IW, Peeling J, Del Bigio MR. Does thrombin play a role in the pathogenesis of brain damage after periventricular hemorrhage? Brain Pathol 2005; 15:241-9. [PMID: 16196391 PMCID: PMC8096014 DOI: 10.1111/j.1750-3639.2005.tb00527.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Neonatal periventricular hemorrhage (PVH) is a devastating complication of prematurity in the human infant. Based upon observations made primarily in adult rodents and the fact that the immature brain uses proteolytic systems for cell migration and growth, we hypothesized that thrombin and plasmin enzyme activities contribute to the brain damage after PVH. The viability of mixed brain cells derived from newborn rat periventricular region was suppressed by whole blood and thrombin, but not plasmin. Following injection of autologous blood into the periventricular region of newborn rat brain, proteolytic activity was detected in a halo around the hematoma using membrane overlays impregnated with thrombin and plasmin fluorogenic substrates. Two-day old rats received periventricular injection of blood, thrombin, and plasminogen. After 2 days, thrombin and blood were associated with significantly greater damage than saline or plasminogen. Two-day old mice received intracerebral injections of blood in combination with saline or the proteolytic inhibitors hirudin, alpha2macroglobulin, or plasminogen activator inhibitor-1. After 2 days, hirudin significantly reduced brain cell death and inflammation. Two-day-old mice then received low and high doses of hirudin mixed with blood after which behavioral testing was conducted repeatedly. At 10 weeks there was no statistically significant evidence for behavioral or structural brain protection. These results indicate that thrombin likely plays a role in neonatal periventricular brain damage following PVH. However, additional factors are likely important in the recovery from this result.
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Affiliation(s)
- Mengzhou Xue
- Departments of Pathology, University of Manitoba, Winnipeg, Canada
- Manitoba Institute of Child Health, Winnipeg, Canada
| | - Janani Balasubramaniam
- Departments of Pathology, University of Manitoba, Winnipeg, Canada
- Manitoba Institute of Child Health, Winnipeg, Canada
| | | | | | - James Peeling
- Departments of Radiology, University of Manitoba, Winnipeg, Canada
| | - Marc R. Del Bigio
- Departments of Pathology, University of Manitoba, Winnipeg, Canada
- Manitoba Institute of Child Health, Winnipeg, Canada
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