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Yamaguchi K, Yazawa T. Development of the human medullary arcuate nucleus from mid-gestation to the perinatal period: A morphometric study. Neurosci Lett 2024; 818:137537. [PMID: 37898180 DOI: 10.1016/j.neulet.2023.137537] [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: 06/15/2023] [Revised: 10/06/2023] [Accepted: 10/26/2023] [Indexed: 10/30/2023]
Abstract
INTRODUCTION Development of the human medullary arcuate nucleus (AN) has not been sufficiently investigated. The present study provides morphometric data by examining the brains from preterm and perinatal infants. MATERIALS AND METHODS Nine brains were obtained from infants aged 21-43 postmenstrual weeks (PW). Serial celloidin sections were cut and stained using the Klüver-Barrera method. After microscopic observations, morphometric parameters [AN volume, numerical density (Nv) and total number (Nt) of neurons, and neuronal profile area (PA)] were analyzed. RESULTS The AN was found as a pair of neuronal masses on the ventral medullary surface at 21 PW. Caudally, it was ventrolateral to the pyramidal tract (PT), and rostrally, medial to the PT. In the middle, it was diminished in size or interrupted. The AN neurons were gradually enlarged with age, showing multiplicity in size and shape. The following findings had a marked asymmetry and individual variability: (1) complete or partial inclusion of the AN in the PT; (2) connection between the rostral AN and the pontine nuclei; (3) coexistence of pyknotic neurons. The AN volume increased exponentially with age, while the Nv decreased exponentially. The Nt changed along two phases (decrease-increase) after mid-gestation. The mean PA increased linearly with age. Asymmetry and/or individual variability were demonstrated in the AN volume, Nt, and mean PA. CONCLUSIONS Asymmetry and individual variability in the AN morphology are present in fetal period. The AN may undergo neuron death and neuroblasts production in tandem after mid-gestation.
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Affiliation(s)
- Katsuyuki Yamaguchi
- Department of Pathology, Dokkyo Medical University School of Medicine, 880 Kitakobayashi, Mibu, Tochigi 321-0293, Japan.
| | - Takuya Yazawa
- Department of Pathology, Dokkyo Medical University School of Medicine, 880 Kitakobayashi, Mibu, Tochigi 321-0293, Japan
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Beltrán-Castillo S, Bravo K, Eugenín J. Impact of Prenatal Nicotine Exposure on Placental Function and Respiratory Neural Network Development. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1428:233-244. [PMID: 37466776 DOI: 10.1007/978-3-031-32554-0_10] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/20/2023]
Abstract
Smoking during pregnancy is associated with multiple undesirable outcomes in infants, such as low birth weight, increased neonatal morbidity and mortality, and catastrophic conditions like sudden infant death syndrome (SIDS). Nicotine, the most addictive and teratogenic substance in tobacco smoke, reaches and crosses the placenta and can be accumulated in the amniotic fluid and distributed by fetal circulation, altering the cholinergic transmission by acting on the nicotinic acetylcholine receptors (nAChRs) expressed from very early gestational stages in the placenta and fetal tissue. Because nAChRs influence the establishment of feto-maternal circulation and the emergence of neuronal networks, prenatal nicotine exposure can lead to multiple alterations in newborns. In this mini-review, we discuss the undeniable effects of nicotine in the placenta and the respiratory neural network as examples of how prenatal nicotine and smoking exposition can affect brain development because dysfunction in this network is involved in SIDS etiology.
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Affiliation(s)
- Sebastián Beltrán-Castillo
- Centro integrativo de Biología y Química Aplicada (CIBQA), Universidad Bernardo O'Higgins, Santiago, Chile.
| | - Karina Bravo
- Laboratorio de Sistemas Neurales, Departamento de Biología, Facultad de Química y Biología, Universidad de Santiago de Chile USACH, Santiago, Chile
- Facultad de Ingeniería, Universidad Autónoma de Chile, Santiago, Chile
| | - Jaime Eugenín
- Laboratorio de Sistemas Neurales, Departamento de Biología, Facultad de Química y Biología, Universidad de Santiago de Chile USACH, Santiago, Chile.
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Baizer JS, Witelson SF. Comparative analysis of four nuclei in the human brainstem: Individual differences, left-right asymmetry, species differences. Front Neuroanat 2023; 17:1069210. [PMID: 36874056 PMCID: PMC9978016 DOI: 10.3389/fnana.2023.1069210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Accepted: 01/24/2023] [Indexed: 02/18/2023] Open
Abstract
Introduction It is commonly thought that while the organization of the cerebral cortex changes dramatically over evolution, the organization of the brainstem is conserved across species. It is further assumed that, as in other species, brainstem organization is similar from one human to the next. We will review our data on four human brainstem nuclei that suggest that both ideas may need modification. Methods We have studied the neuroanatomical and neurochemical organization of the nucleus paramedianus dorsalis (PMD), the principal nucleus of the inferior olive (IOpr), the arcuate nucleus of the medulla (Arc) and the dorsal cochlear nucleus (DC). We compared these human brainstem nuclei to nuclei in other mammals including chimpanzees, monkeys, cats and rodents. We studied human cases from the Witelson Normal Brain collection using Nissl and immunostained sections, and examined archival Nissl and immunostained sections from other species. Results We found significant individual variability in the size and shape of brainstem structures among humans. There is left-right asymmetry in the size and appearance of nuclei, dramatically so in the IOpr and Arc. In humans there are nuclei, e.g., the PMD and the Arc, not seen in several other species. In addition, there are brainstem structures that are conserved across species but show major expansion in humans, e.g., the IOpr. Finally, there are nuclei, e.g. the DC, that show major differences in structure among species. Discussion Overall, the results suggest several principles of human brainstem organization that distinguish humans from other species. Studying the functional correlates of, and the genetic contributions to, these brainstem characteristics are important future research directions.
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Affiliation(s)
- Joan S Baizer
- Department of Physiology and Biophysics, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, United States
| | - Sandra F Witelson
- Department of Psychiatry and Behavioural Neurosciences, Michael G. DeGroote School of Medicine, Faculty of Health Sciences, McMaster University, Hamilton, ON, Canada
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Brendel VA, Schmeisser MJ, Schumann S. A morphometric analysis of the circumolivary fiber bundle of the human brainstem. Front Neuroanat 2022; 16:990862. [DOI: 10.3389/fnana.2022.990862] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2022] [Accepted: 10/28/2022] [Indexed: 11/17/2022] Open
Abstract
The circumolivary fiber bundle (CFB) is considered to be an anatomical variation, which can be found on the surface of the human medulla oblongata. The macroscopical fiber bundle runs downwards from either the anterior median fissure, the pyramid, or both, around the inferior pole of the olive and turns upwards to reach the restiform body of the inferior cerebellar peduncle. Multiple fiber systems feed the constitution of the CFB (collateral corticospinal fibers, fibers connecting to the reticular formation, anterior external arcuate fibers). With this examination we provide a systematic analysis of the frequency of occurrence (6.14%), size, and laterality of the CFB. Including all three fiber bundle parts (descending part, genu, and ascending part), the left-sided sizes were increased. Likewise, the appearance of an unilateral left-sided CFB could be detected in more than 60% of our cases. Our morphometrical analysis currently covers the largest sample of investigated brainstem sides (n = 489) so far. This investigation should widen the perspective on how anatomists, neuroradiologists, and neurosurgeons expect the anterolateral surface of the human medulla oblongata.
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Lavezzi AM, Pusiol T, Paradiso B. Harmful Effect of Intrauterine Smoke Exposure on Neuronal Control of "Fetal Breathing System" in Stillbirths. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:ijerph19074164. [PMID: 35409845 PMCID: PMC8999022 DOI: 10.3390/ijerph19074164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Revised: 03/29/2022] [Accepted: 03/30/2022] [Indexed: 02/04/2023]
Abstract
This article is aimed to contribute to the current knowledge on the role of toxic substances such as nicotine on sudden intrauterine unexplained deaths’ (SIUDS’) pathogenetic mechanisms. The in-depth histopathological examination of the autonomic nervous system in wide groups of victims of SIUDS (47 cases) and controls (20 cases), with both smoking and no-smoking mothers, highlighted the frequent presence of the hypodevelopment of brainstem structures checking the vital functions. In particular, the hypoplasia of the pontine parafacial nucleus together with hypoplastic lungs for gestational age were observed in SIUDS cases with mothers who smoked cigarettes, including electronic ones. The results allow us to assume that the products of cigarette smoke during pregnancy can easily cross the placental barrier, thus entering the fetal circulation and damaging the most sensitive organs, such as lungs and brain. In a non-negligible percentage of SIUDS, the mothers did not smoke. Furthermore, based on previous and ongoing studies conducted through analytical procedures and the use of scanning electron microscopy, the authors envisage the involvement of toxic nanoparticles (such as agricultural pesticides and nanomaterials increasingly used in biomedicine, bioscience and biotechnology) in the death pathogenesis, with similar mechanisms to those of nicotine.
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Affiliation(s)
- Anna M. Lavezzi
- “Lino Rossi” Research Center for the Study and Prevention of Unexpected Perinatal Death and SIDS, Department of Biomedical, Surgical and Dental Sciences, University of Milan, 20121 Milan, Italy;
- Correspondence:
| | - Teresa Pusiol
- Institute of Anatomic Pathology, APSS, 38122 Trento, Italy;
| | - Beatrice Paradiso
- “Lino Rossi” Research Center for the Study and Prevention of Unexpected Perinatal Death and SIDS, Department of Biomedical, Surgical and Dental Sciences, University of Milan, 20121 Milan, Italy;
- General Pathology Unit, Dolo Hospital, 30031 Dolo, Italy
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Baizer JS, Webster CJ, Witelson SF. Individual variability in the size and organization of the human arcuate nucleus of the medulla. Brain Struct Funct 2021; 227:159-176. [PMID: 34613435 DOI: 10.1007/s00429-021-02396-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Accepted: 09/23/2021] [Indexed: 12/11/2022]
Abstract
The arcuate nucleus (Arc) of the medulla is found in almost all human brains and in a small percentage of chimpanzee brains. It is absent in the brains of other mammalian species including mice, rats, cats, and macaque monkeys. The Arc is classically considered a precerebellar relay nucleus, receiving input from the cerebral cortex and projecting to the cerebellum via the inferior cerebellar peduncle. However, several studies have found aplasia of the Arc in babies who died of SIDS (Sudden Infant Death Syndrome), and it was suggested that the Arc is the locus of chemosensory neurons critical for brainstem control of respiration. Aplasia of the Arc, however, has also been reported in adults, suggesting that it is not critical for survival. We have examined the Arc in closely spaced Nissl-stained sections in thirteen adult human cases to acquire a better understanding of the degree of variability of its size and location in adults. We have also examined immunostained sections to look for neurochemical compartments in this nucleus. Caudally, neurons of the Arc are ventrolateral to the pyramidal tracts (py); rostrally, they are ventro-medial to the py and extend up along the midline. In some cases, the Arc is discontinuous, with a gap between sections with the ventrolaterally located and the ventromedially located neurons. In all cases, there is some degree of left-right asymmetry in Arc position, size, and shape at all rostro-caudal levels. Somata of neurons in the Arc express calretinin (CR), neuronal nitric oxide synthase (nNOS), and nonphosphorylated neurofilament protein (NPNFP). Calbindin (CB) is expressed in puncta whereas there is no expression of parvalbumin (PV) in somata or puncta. There is also immunostaining for GAD and GABA receptors suggesting inhibitory input to Arc neurons. These properties were consistent among cases. Our data show differences in location of caudal and rostral Arc neurons and considerable variability among cases in the size and shape of the Arc. The variability in size suggests that "hypoplasia" of the Arc is difficult to define. The discontinuity of the Arc in many cases suggests that establishing aplasia of the Arc requires examination of many closely spaced sections through the brainstem.
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Affiliation(s)
- Joan S Baizer
- Department of Physiology and Biophysics, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, 123 Sherman Hall, South Campus, Buffalo, NY, 14214, USA.
| | - Charles J Webster
- Department of Physiology and Biophysics, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, 123 Sherman Hall, South Campus, Buffalo, NY, 14214, USA
| | - Sandra F Witelson
- Department of Psychiatry and Behavioural Neurosciences, Michael G. DeGroote School of Medicine, McMaster University, Hamilton, ON, L8S 4K1, Canada
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Stonebridge R, Taliano RJ, Velilla TD, Anthony DC. Hypertrophy of the Anterior External Arcuate Fasciculus: A Rare Variant With Implications for the Development of the Arcuate Nucleus. Front Neuroanat 2020; 14:595500. [PMID: 33328906 PMCID: PMC7729007 DOI: 10.3389/fnana.2020.595500] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2020] [Accepted: 10/27/2020] [Indexed: 11/17/2022] Open
Abstract
A rare anatomic variant of a markedly enlarged anterior external arcuate fasciculus (AEAF) on the ventral medullary surface is reported and compared to two controls. The hypertrophic AEAF was nine times larger in diameter than normal, whereas the arcuate nucleus (AN) and inferior olivary nucleus (ION) appeared histologically normal in size and neuronal distribution, and morphometric analysis of the AN confirmed that it was within the normal range. Calbindin-2 (calretinin, CALB2) expression was identified in the AN and in the fibers of the normal AEAF. The hypertrophic AEAF did not contain calbindin-2–expressing fibers. CALB2 expression was also present in the ventrolateral portion of the ION, both in the index case and in one of the control cases. The origin of the additional fibers was not identified; however, the potential origin of these fibers and its implications for the development of the AEAF are discussed.
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Affiliation(s)
- Renee Stonebridge
- Department of Pathology and Laboratory Medicine, Lifespan Academic Medical Center, Providence, RI, United States.,Department of Pathology and Laboratory Medicine, Warren Alpert Medical School of Brown University, Providence, RI, United States
| | - Ross J Taliano
- Department of Pathology and Laboratory Medicine, Lifespan Academic Medical Center, Providence, RI, United States.,Department of Pathology and Laboratory Medicine, Warren Alpert Medical School of Brown University, Providence, RI, United States
| | - Terra D Velilla
- Department of Pathology and Laboratory Medicine, Lifespan Academic Medical Center, Providence, RI, United States
| | - Douglas C Anthony
- Department of Pathology and Laboratory Medicine, Lifespan Academic Medical Center, Providence, RI, United States.,Department of Pathology and Laboratory Medicine, Warren Alpert Medical School of Brown University, Providence, RI, United States.,Department of Neurology, Warren Alpert Medical School of Brown University, Providence, RI, United States
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Paradiso B, Ferrero S, Thiene G, Lavezzi AM. Variability of the medullary arcuate nucleus in humans. Brain Behav 2018; 8:e01133. [PMID: 30329220 PMCID: PMC6236238 DOI: 10.1002/brb3.1133] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Revised: 09/09/2018] [Accepted: 09/11/2018] [Indexed: 11/10/2022] Open
Abstract
INTRODUCTION The arcuate nucleus is a component of the ventral medullary surface involved in chemoreception and breathing control. The hypoplasia of this nucleus is a very frequent finding in victims of sudden unexplained fetal and infant death (from the last weeks of pregnancy to the first year of life). On the contrary, this developmental alteration is rarely present in age-matched controls who died of defined causes. These observations lead to hypothesize that a well-developed and functional arcuate nucleus is generally required to sustain life. The aim of this study was to investigate whether the arcuate nucleus maintains the same supposed function throughout life. METHODS We carried out neuropathological examinations of brainstems obtained from 25 adult subjects, 18 males and 7 females, aged between 34 and 89 years, who died from various causes. RESULTS For almost half of the cases (44%) microscopic examinations of serial histological sections of medulla oblongata showed a normal cytoarchitecture of the arcuate nucleus, extending along the pyramids. For the remaining 56% of cases, various degrees of hypodevelopment of this nucleus were observed, validated through the application of quantitative morphometric investigations, from decreased area, neuron number and volume, to full aplasia. CONCLUSIONS These unexpected findings indicate that the involvement of the arcuate nucleus in chemoreception in adulthood is questionable, given the possibility of living until late age without this nucleus. This opens new perspectives for researchers on the role and function of the arcuate nucleus in humans from birth to old age.
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Affiliation(s)
- Beatrice Paradiso
- ”Lino Rossi” Research Center for the Study and Prevention of Unexpected Perinatal Death and SIDS—Department of Biomedical, Surgical and Dental SciencesUniversity of MilanMilanItaly
- Department of Cardiac, Thoracic and Vascular SciencesUniversity of PaduaPaduaItaly
| | - Stefano Ferrero
- ”Lino Rossi” Research Center for the Study and Prevention of Unexpected Perinatal Death and SIDS—Department of Biomedical, Surgical and Dental SciencesUniversity of MilanMilanItaly
- Division of PathologyFondazione IRCCS Ca' Granda, Ospedale Maggiore PoliclinicoMilanItaly
| | - Gaetano Thiene
- Department of Cardiac, Thoracic and Vascular SciencesUniversity of PaduaPaduaItaly
| | - Anna Maria Lavezzi
- ”Lino Rossi” Research Center for the Study and Prevention of Unexpected Perinatal Death and SIDS—Department of Biomedical, Surgical and Dental SciencesUniversity of MilanMilanItaly
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