A Covid-19 e as citocinas: uma revisão de literatura / Covid-19 and cytokines: a literature review / Covid-19 y citocinas: una revisión de la literatura

A COVID-19 surgiu em dezembro de 2019 na China, o contágio se espalhou rapidamente pelo mundo e já em março de 2020 a Organização Mundial da Saúde (OMS) declarou o surto como pandemia. A infecção causada por SARS-COV-2 mostrou-se com sintomatologia variada. Enquanto alguns infectados não tinham sintomas, outros apresentavam sinais que variam dos semelhantes a uma gripe, até uma possível evolução para síndrome do desconforto respiratório. Evidências indicam que, durante o curso da COVID-19 a rápida progressão e mortalidade pode ter sido associada à mecanismo hiperinflamatórios, com descontrole regulatório da produção de citocinas pró- inflamatórias, tanto em nível local, quanto sistêmico. Sendo assim, neste artigo revisamos a literatura sobre a COVID-19, seus aspectos epidemiológicos e clínicos, bem como a o papel das citocinas no contexto da infecção por SARS-CoV-2, já que a busca pelo entendimento dos mecanismos imunológicos que envolvem a COVID-19 e outras doenças de caráter inflamatório é de suma importância para o tratamento e o manejo de tais enfermidades.

COVID-19 emerged in December 2019 in China, the contagion spread rapidly around the world, and already in March 2020 the World Health Organization (WHO) declared the outbreak a pandemic. The infection caused by SARS-COV-2 was shown to have varied symptomatology. While some infected people had no symptoms, others showed signs ranging from flu-like to a possible evolution to respiratory distress syndrome. Evidence indicates that during the course of COVID-19 the rapid progression and mortality may have been associated with hyperinflammatory mechanisms, with regulatory uncontrolled production of pro-inflammatory cytokines at both local and systemic levels. Therefore, in this article we review the literature on COVID-19, its epidemiological and clinical aspects, as well as the role of cytokines in the context of SARS-CoV-2 infection, since the search for understanding the immunological mechanisms surrounding COVID-19 and other inflammatory diseases is of paramount importance for the treatment and management of such diseases.

El COVID-19 surgió en diciembre de 2019 en China, el contagio se extendió rápidamente por todo el mundo y ya en marzo de 2020 la Organización Mundial de la Salud (OMS) declaró el brote como pandemia. Se demostró que la infección causada por el SARS-COV-2 presentaba una sintomatología variada. Mientras que algunos infectados no presentaban síntomas, otros mostraban signos que iban desde similares a los de la gripe hasta una posible evolución a síndrome de dificultad respiratoria. Las pruebas indican que durante el curso del COVID-19 la rápida progresión y la mortalidad pueden haber estado asociadas a mecanismos hiperinflamatorios, con una producción descontrolada reguladora de citocinas proinflamatorias tanto a nivel local como sistémico. Por lo tanto, en este artículo revisamos la literatura sobre la COVID-19, sus aspectos epidemiológicos y clínicos, así como el papel de las citocinas en el contexto de la infección por SARS-CoV-2, ya que la búsqueda de la comprensión de los mecanismos inmunológicos que rodean la COVID-19 y otras enfermedades inflamatorias es de suma importancia para el tratamiento y la gestión de dichas enfermedades.

Prepubertal acrylamide exposure causes dose-response decreases in spermatic production and functionality with modulation of genes involved in the spermatogenesis in rats.

The increase in human infertility prevalence due to male reproductive disorders has been associated with extensive endocrine-disrupting chemical (EDC) exposure. Acrylamide (AA) is a compound formed spontaneously during heat processing of some foods that are mainly consumed by children and adolescents. In this study, we evaluated the prepubertal AA exposure effects on male adult reproductive physiology using a prepubertal experimental model to analyze the pubertal development, spermatogenesis hormones levels and genes expression involved in male reproductive function. This study is the first one to use the validated protocol to correlate the AA exposure with puberty development, as well as the AA-induced endocrine disrupting effects on reproductive axis. AA did not affect the age at puberty, the reproductive organ's weight and serum hormonal levels. AA reduces spermatogenesis, induces morphological and functional defects on sperm and alters transcript expression of sexual hormone receptors (Ar and Esr2), the transcript expression of Tnf, Egr2, Rhcg and Lrrc34. These findings suggest that excessive AA consumption may impair their reproductive capacity at adulthood, despite no changes in hormonal profile being observed.

Acrylamide induces a thyroid allostasis-adaptive response in prepubertal exposed rats.

Some endocrine-disrupting chemicals (EDCs) can affect the endocrine system through covalent interactions with specific sites, leading to deregulation of physiological homeostasis. The acrylamide (AA) present in some fried or baked foods is an example of an electrophile molecule that is able to form adducts with nucleophilic regions of nervous system proteins leading to neurological defects. A positive correlation between increased urinary AA metabolite concentration and reduced levels of thyroid hormones (TH) was described in adolescents and young adults. Thus, this study aimed to evaluate whether AA affects the physiology of the hypothalamus-pituitary-thyroid (HPT) axis and the possible repercussions in peripheral TH-target systems. For this, male Wistar rats were exposed to doses of 2.5 or 5.0 mg AA/Kg/day, based on the LOAEL (Lowest Observed Adverse Effect Level) during prepubertal development. The expression of molecular markers of HPT functionality was investigated in the hypothalamus, pituitary, thyroid, heart and liver, as well as the hormonal and lipid profiles in blood samples. Herein, we showed that AA acts as EDCs for thyroid gland function, increasing the transcript expression of several proteins related to TH synthesis and altering hypothalamus-pituitary-thyroid axis homeostasis, an effect evidenced by the higher levels of THs in the serum. Compensatory mechanisms were observed in TH-target tissues, such as an increase in Dio3 mRNA expression in the liver and a reduction in Mct8 transcript content in the hearts of AA-treated rats. Together, these results pointed out an allostatic regulation of the HPT axis induced by AA and suggest that chronic exposure to it, mainly associated with food consumption, might be related to the higher prevalence of thyroid dysfunctions.

Acrylamide: A review about its toxic effects in the light of Developmental Origin of Health and Disease (DOHaD) concept.

The endocrine system is highly sensitive to endocrine-disrupting chemicals (EDC) which interfere with metabolism, growth and reproduction throughout different periods of life, especially in the embryonic and pubertal stages, in which gene reprogramming may be associated with impaired development and control of tissues/organs even in adulthood. Acrylamide is considered a potential EDC and its main source comes from fried, baked and roasted foods that are widely consumed by children, teenagers and adults around the world. This review aimed to present some aspects regarding the acrylamide formation, its toxicokinetics, the occurrence of acrylamide in foods, the recent findings about its effects on different systems and the consequences for the human healthy. The challenges to characterize the molecular mechanisms triggered by acrylamide and to establish safe levels of consumption and/or exposure are also discussed in the present review.