ABSTRACT
Resumen La pandemia COVID-19 se extendió por todo por a la enorme capacidad del coronavirus SARS-CoV-2 para transmitirse entre humanos. El COVID-19 es una amenaza para la salud pública mundial. La entrada de este virus en las células se ve muy facilitada por la presencia de la enzima convertidora de angiotensina 2 (ACE2) en la membrana celular. Hoy en día no tenemos un conocimiento preciso de cómo se expresa este receptor en el cerebro durante el desarrollo humano y, como consecuencia, no sabemos si las células neurales en desarrollo son susceptibles de ser infectadas a través de la transmisión de madre a feto. Revisamos en este artículo los conocimientos sobre la expresión de ACE2 en el cerebro humano en desarrollo, con especial atención a la etapa fetal. Esta etapa corresponde al periodo de formación de la corteza cerebral. La posibilidad de infección por SARS-CoV-2 durante el periodo fetal puede alterar el desarrollo normal de la corteza cerebral. Así pues, aunque se han publicado pocos casos demostrando la transmisión vertical de la infección por SARS-CoV-2, el gran número de jóvenes infectados puede representar un problema sanitario que necesite seguimiento, por la posibilidad de que se originen alteraciones cognitivas y anomalías en el desarrollo de los circuitos corticales, que pueden representar predisposición a padecer problemas mentales a lo largo de la vida.
Abstract The COVID-19 pandemic spread around the world due to the enormous transmission of the SARS-CoV-2 among humans. COVID-19 represents a threat to global public health. The entry of this virus into cells is greatly facilitated by the presence of angiotensin-converting enzyme 2 (ACE2) in the cell membrane. Today we do not have a precise understanding of how this receptor expresses in the brain during human development and, as a consequence, we do not know whether neural cells in the developing brain are susceptible to infection. We review the knowledge about ACE2 expression in the developing human brain, with special attention to the fetal stage. This stage corresponds to the period of the cerebral cortex formation. Therefore, SARS-CoV-2 infection during the fetal period may alter the normal development of the cerebral cortex. Although few cases have been published demonstrating vertical transmission of SARS-CoV-2 infection, the large number of infected young people may represent a problem which requires health surveillance, due to the possibility of cognitive alterations and abnormalities in the development of cortical circuits that may represent a predisposition to mental problems later in life.
ABSTRACT
Abstract The agent that causes the coronavirus disease (COVID-19), associated with the severe acute respiratory syndrome (SARS-CoV-2), produces a spectrum of symptoms that mainly affect the respiratory system, the central nervous system (CNS), the regulation of hemostasis and the immune system. Bilateral vocal fold paralysis (BVFP) is a condition of unknown incidence among infected patients, either because it is short-lived or because of the difficulty in establishing a direct cause to the virus. Viral infection has been described in the literature as a cause of BVFP and there is the suspicion that a proportion of the idiopathic cases are due to undiagnosed viral infections. Although the neurotropic mechanisms for SARS-CoV-2 remain unclear, there is strong evidence to ensure its neuroinvasive potential. The most frequent etiologies of BVFP are trauma, neoplasm, and neurological, but a viral origin should not be ruled out. Causality between COVID-19 and BVFP is plausible and will require further study in the short and long term. We present a case series that support and discuss the hypothesis under consideration.
Resumen El agente causal de la enfermedad por coronavirus (COVID-19), asociado a síndrome respiratorio agudo grave (SARS-CoV-2), genera un espectro de síntomas que afectan fundamentalmente el sistema respiratorio, el sistema nervioso central (SNC), la regulación hemostásica y el sistema inmune. La parálisis bilateral de cuerdas vocales (PBCV) es una entidad cuya incidencia en infectados se desconoce, bien porque no se presentan durante el tiempo suficiente o por la dificultad de establecer una causalidad directa con el virus. La infección vírica, como causa de PBCV, está descrita en la literatura y se sospecha que una parte de los casos idiopáticos corresponden a infecciones víricas no diagnosticadas. Aunque los mecanismos neurotrópicos no están completamente aclarados para el SARS-CoV-2, existen indicios sólidos para asegurar su potencial neuroinvasivo. Las causas traumáticas, neoplásicas y neurológicas son las etiologías más comunes de PBCV, sin que se pueda descartar el origen vírico. Es plausible una causalidad entre el COVID-19 y la PBCV, que requerirá mayores estudios a corto y largo plazo. Presentamos una serie de casos que sostienen y discuten la hipótesis en consideración.
Subject(s)
Pancreas DivisumABSTRACT
Resumen: La enfermedad por coronavirus ha extendido su compromiso más allá del sistema respiratorio con reportes crecientes de compromiso en diferentes sistemas, uno de ellos, el Sistema Nervioso. El potencial neuroinvasivo de este agente patógeno se explicaría por su neurotropismo dada la presencia de receptores de ACE2 a nivel de encéfalo y médula espinal, además del importante com promiso inflamatorio sistémico. El compromiso neurológico debido a la infección se ha dividido en Sistema Nervioso Central, destacando síntomas inespecíficos y leves como mareos y cefalea, así como cuadros graves con encefalitis y patología cerebrovascular, y Sistema Nervioso Periférico en donde la mayor relevancia guarda relación con la anosmia, ageusia y miositis. A nivel pediátrico el compromiso parece ser menor que en adultos, pero existe un reporte creciente en la literatura respecto a estos hallazgos. Es de gran importancia de contar con un adecuado registro y anamnesis que permita identificar precozmente el compromiso neurológico.
Abstract: Coronavirus disease has extended its involvement beyond the respiratory system, with increasing reports of involving different systems, such as Nervous System. The neuroinvasive potential of this pathogen would be explained by its neurotropism given the presence of ACE2 receptors in the brain and spinal cord, in addition to the important systemic inflammatory involvement. The neu rological involvement due to infection is divided between the central nervous system, highlighting non-specific and mild symptoms such as dizziness and headache, as well as severe symptoms with encephalitis and cerebrovascular pathology, and the peripheral nervous system, which mainly pre sents anosmia, ageusia, and myositis. Clinical symptomatology in pediatric patients seems to be less than in adults, but there is a growing report in the literature regarding these findings. There fore, it is very important to have an adequate registry and anamnesis that allow early identification of neurological involvement.
Subject(s)
Humans , Child , Pneumonia, Viral/complications , Coronavirus Infections/complications , Peptidyl-Dipeptidase A/metabolism , Nervous System Diseases/virology , Pediatrics , Age Factors , Encephalitis/virology , Headache/virology , Nervous System Diseases/physiopathologyABSTRACT
The proportion of the reported cases of Zika virus (ZIKV) infection reached the status of a pandemic. Numerous studies are being conducted on the isolation of ZIKV strains from various epidemics, diagnosis of the infections, various animal models and cell culture designs to study the pathogenesis of ZIKV in the attempts to find an effective ZIKV vaccine. This review focuses upon the ‘Off-Spectrum’ body of studies which analyses the epidemiology, pathogenesis and other attributes of ZIKV in the light of various dissident hypotheses.
ABSTRACT
The proportion of the reported cases of Zika virus (ZIKV) infection reached the status of a pandemic. Numerous studies are being conducted on the isolation of ZIKV strains from various epidemics, diagnosis of the infections, various animal models and cell culture designs to study the pathogenesis of ZIKV in the attempts to find an effective ZIKV vaccine. This review focuses upon the 'Off-Spectrum' body of studies which analyses the epidemiology, pathogenesis and other attributes of ZIKV in the light of various dissident hypotheses.
ABSTRACT
An unusually high incidence of microcephaly in newborns has recently been observed in Brazil. There is a temporal association between the increase in cases of microcephaly and the Zika virus (ZIKV) epidemic. Viral RNA has been detected in amniotic fluid samples, placental tissues and newborn and fetal brain tissues. However, much remains to be determined concerning the association between ZIKV infection and fetal malformations. In this study, we provide evidence of the transplacental transmission of ZIKV through the detection of viral proteins and viral RNA in placental tissue samples from expectant mothers infected at different stages of gestation. We observed chronic placentitis (TORCH type) with viral protein detection by immunohistochemistry in Hofbauer cells and some histiocytes in the intervillous spaces. We also demonstrated the neurotropism of the virus via the detection of viral proteins in glial cells and in some endothelial cells and the observation of scattered foci of microcalcifications in the brain tissues. Lesions were mainly located in the white matter. ZIKV RNA was also detected in these tissues by real-time-polymerase chain reaction. We believe that these findings will contribute to the body of knowledge of the mechanisms of ZIKV transmission, interactions between the virus and host cells and viral tropism.
Subject(s)
Humans , Male , Female , Infant, Newborn , Adult , Infectious Disease Transmission, Vertical , Microcephaly/virology , Viral Tropism/physiology , Zika Virus Infection/congenital , Zika Virus/physiology , Amniotic Fluid/virology , Brain/embryology , Brain/virology , Immunohistochemistry , Infant, Newborn , Placenta/virology , Pregnancy , RNA, Viral/analysisABSTRACT
Dengue virus (DENV) infects approximately 390 million persons every year in more than 100 countries. Reports of neurological complications are more frequently. The objective of this narrative review is to bring up the advances in the dengue neuropathogenesis. DENV can access the nervous system through blood-brain barrier disturbance mediated by cytokine. The blood-cerebrospinal fluid (CSF) barrier seems to be also involved, considering the presence of the virus in the CSF of patients with neurological manifestations. As for neurotropism, several studies showed the presence of RNA and viral antigens in brain tissue and CSF in humans. In murine model, different virus mutations were associated to neurovirulence. Despite the advances in the dengue neuropathogenesis, it is still necessary to determine a more appropriate animal model and increase the number of cases of autopsy. The detection of neurovirulence markers may contribute to establish a prognosis, the disease control and vaccine development.
O vírus da dengue (DENV) infecta anualmente cerca de 390 milhões de indivíduos em mais de 100 países. Complicações neurológicas estão se tornando frequentes. O objetivo desta revisão narrativa é abordar os avanços sobre neuropatogênese na dengue. O DENV invade o sistema nervoso central através do distúrbio da barreira hemato-encefálica, mediado por citocina. A barreira hemato-liquórica (LCR) parece também estar envolvida, considerando a presença do vírus no LCR. Estudos demonstraram RNA e antígenos virais no tecido cerebral e LCR de indivíduos infectados pelo DENV, confirmando o neurotropismo viral. Em modelo murino, diferentes mutações virais foram associadas a neurovirulência. Apesar dos avanços no conhecimento da neuropatogênese da dengue, ainda são necessários a determinação de um modelo animal mais adequado e aumento do número de casos de autopsia. A determinação de marcadores de neurovirulência pode contribuir para o estabelecimento de prognóstico, controle da doença e no desenvolvimento de vacina.
Subject(s)
Animals , Humans , Central Nervous System Diseases/virology , Dengue Virus , Dengue/complications , Central Nervous System/virology , Disease Models, Animal , Dengue Virus/genetics , Dengue/virology , Medical Illustration , MutationABSTRACT
Objective To study the mutations of Env sequence of SIVmac239 after infection of Chinese rhesus monkeys, and compare the differences and characteristics of Gp120 sequences of enterotropic and neurotropic SIV strains. Methods Six strains of simian immunodeficiency virus were analyzed in this study: four separated from peripheral blood mononuclear cells of SIVmac239-infected monkeys and two neurotropic SIVmac251 strains.Isolated and cultured monoclonal virus was obtained by limiting dilution assay.Gp120 sequences were amplified after the RNA extraction and phylogenetic analysis was processed thereafter.So did the Gp120 amino acid sequence and N-glycosylation sites analysis of the enterotropic and neurotropic strains.Results SIVmac239 had different mutations in four rhesus monkeys.The diversity in amino acid sequences of the enterotropic and neurotropic strains concentrated in the V1 and V4 regions of Gp120.The enterotropic strains had an addition of glycosylation site in V4 but the glycosylation site changes of neurotropic strains were located in the conservative regions of C1, C2 and C3.Conclusions The addition of one glycosylation site in V4 region of GP120 and loss of one glycosylation site in C1 region are associated with enhanced enterotropism and neurotropism.The differences between the enterotropic and neurotropic strains are not dipicted in Gp120 V3 region which is closely related with the tropism of strains.