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Eur Rev Med Pharmacol Sci ; 26(8): 3025-3029, 2022 Apr.
Article in English | MEDLINE | ID: covidwho-1836395


OBJECTIVE: Previous studies have confirmed the key mechanism by which SARS-CoV-2 enters human cells. It is well established that ACE2 is the receptor that can mark the beginning of the infection. In light of this, the organs that express higher levels of ACE2 are generally considered at higher risk, while those with lower levels should be somehow more protected. This - if related to the scarcity of ace2-expressing cells in the brain - seems to contrast with the presence of a variety of neurological symptoms that follow infection with ace2.  The aim of this work was to analyze ACE2 expression in the human brain, focusing on the choroid plexuses. PATIENTS AND METHODS: Twenty brain samples were obtained at autopsy from ten human fetuses and from ten adult subjects. All samples were selected to contain the choroid plexus. Specimens were fixed in 10% formalin, routinely processed and paraffin embedded. 5-micron sections were stained with Hematoxylin and Eosin (H&E) and immunostained with a commercial anti-human ACE2 rabbit monoclonal antibody at 1:100 dilution. RESULTS: We analyzed 20 samples by immunohistochemistry, and we noted that, as far as fetal samples are concerned, a strong reactivity for ACE2 was detected in the myxoid stroma of the choroid plexuses and in the endothelial cells in fetuses. The complete absence of the ACE2 marker was detected in epithelial cells, neurons and glial cells of the cerebral cortex, both in fetuses and in adults. Whereas a  strong but selective reactivity for ACE2 was also detected in adult choroid plexuses, mainly localized in the endothelial cells of the choroid capillaries. CONCLUSIONS: Our study shows a strong expression of ACE in the fetal and adult brain choroid plexuses. This new histopathological finding may clarify the susceptibility of the human brain to SARS-COV-2 infection. Our data indicate the choroid plexus as the entry gate of virus for in the human brain; therefore, the entrance of SARS-CoV-2 into the cerebrospinal fluid through the choroid plexuses might represent the mechanism utilized by this coronavirus to cause direct injury to brain cells.

Angiotensin-Converting Enzyme 2 , COVID-19 , Choroid , Choroid Plexus , Endothelial Cells , Humans , SARS-CoV-2
Eur Rev Med Pharmacol Sci ; 25(18): 5876-5884, 2021 Sep.
Article in English | MEDLINE | ID: covidwho-1451047


The risk stratification of young adults between subjects who will develop a mild form COVID-19 and subjects who will undergo a severe disease remains inaccurate. In this review, we propose that the Barker hypothesis might explain the increased susceptibility to severe forms of COVID-19 in subjects who underwent intrauterine growth restriction (IUGR). In this paper evidence indicating an association between a low birth weight and an adult phenotype which might favor a severe outcome of SARS-CoV-2 infection are presented: lower lung functional capacity; increased respiratory morbidity; changes in fibrinogen and Factor VII serum levels and dysregulation of the hemostasis and thrombosis system; acquisition of a pro-thrombotic phenotype; low nephron number, with decreased ability to sustain renal function and increased renal morbidity; heart remodeling, with a less efficient cardiac function; endothelial dysfunction, a risk factor for the insurgence of the multiple organ failure; remodeling of arteries, with changes in the elastic properties of the arterial wall, predisposing to the insurgence and progression of atherosclerosis; dysfunction of the innate immune system, a risk factor for immune diseases in adulthood. These data suggest that young and adult subjects born too small (IUGR) or too early (pre-terms) might represent a subgroup of "at risk subjects", more susceptible toward severe forms of COVID-19. Given that LBW may be considered a surrogate of IUGR, this phenotypic marker should be included among the indispensable clinical data collected in every patient presenting with SARS-COV-2 infection, irrespectively of his/her age.

COVID-19/epidemiology , Disease Susceptibility/epidemiology , Fetal Development , Disease Susceptibility/virology , Fetal Growth Retardation , Humans , Infant, Low Birth Weight , Severity of Illness Index , Young Adult
Eur Rev Med Pharmacol Sci ; 24(23): 12609-12622, 2020 12.
Article in English | MEDLINE | ID: covidwho-995022


OBJECTIVE: In human pathology, SARS-CoV-2 utilizes multiple molecular pathways to determine structural and biochemical changes within the different organs and cell types. The clinical picture of patients with COVID-19 is characterized by a very large spectrum. The reason for this variability has not been clarified yet, causing the inability to make a prognosis on the evolution of the disease. MATERIALS AND METHODS: PubMed search was performed focusing on the role of ACE 2 receptors in allowing the viral entry into cells, the role of ACE 2 downregulation in triggering the tissue pathology or in accelerating previous disease states, the role of increased levels of Angiotensin II in determining endothelial dysfunction and the enhanced vascular permeability, the role of the dysregulation of the renin angiotensin system in COVID-19 and the role of cytokine storm. RESULTS: The pathological changes induced by SARS-CoV-2 infection in the different organs, the correlations between the single cell types targeted by the virus in the different human organs and the clinical consequences, COVID-19 chronic pathologies in liver fibrosis, cardiac fibrosis and atrial arrhythmias, glomerulosclerosis and pulmonary fibrosis, due to the systemic fibroblast activation induced by angiotensin II are discussed. CONCLUSIONS: The main pathways involved showed different pathological changes in multiple tissues and the different clinical presentations. Even if ACE2 is the main receptor of SARS-CoV-2 and the main entry point into cells for the virus, ACE2 expression does not always explain the observed marked inter-individual variability in clinical presentation and outcome, evidencing the complexity of this disorder. The proper interpretation of the growing data available might allow to better classifying COVID-19 in human pathology.

Angiotensin II/metabolism , Angiotensin-Converting Enzyme 2/metabolism , COVID-19/metabolism , Cardiomyopathies/metabolism , Cytokine Release Syndrome/metabolism , Endothelium, Vascular/physiopathology , Liver Cirrhosis/metabolism , Systemic Inflammatory Response Syndrome/metabolism , Thrombosis/metabolism , Angiotensin I/metabolism , Atrial Fibrillation/metabolism , Atrial Fibrillation/physiopathology , Blood Coagulation , COVID-19/pathology , COVID-19/physiopathology , Capillary Permeability , Cardiomyopathies/pathology , Cardiomyopathies/physiopathology , Cytokine Release Syndrome/physiopathology , Cytokines/metabolism , Fibroblasts/metabolism , Fibroblasts/pathology , Fibrosis , Humans , Liver Cirrhosis/pathology , Liver Cirrhosis/physiopathology , Myocarditis/metabolism , Myocarditis/pathology , Myocarditis/physiopathology , Receptors, Coronavirus/metabolism , Renin-Angiotensin System , SARS-CoV-2/metabolism , Systemic Inflammatory Response Syndrome/physiopathology , Thrombosis/physiopathology , Virus Internalization