Strong ACE-2 expression in the choroidal vessels: do high choroid plexuses serve as a gateway for SARS-CoV-2 infection on the human brain?

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.

Evaluation of COVID-19 impact on DELAYing diagnostic-therapeutic pathways of lung cancer patients in Italy (COVID-DELAY study): fewer cases and higher stages from a real-world scenario.

INTRODUCTION: COVID-19 has disrupted the global health care system since March 2020. Lung cancer (LC) patients (pts) represent a vulnerable population highly affected by the pandemic. This multicenter Italian study aimed to evaluate whether the COVID-19 outbreak had an impact on access to cancer diagnosis and treatment of LC pts compared with pre-pandemic time. METHODS: Consecutive newly diagnosed LC pts referred to 25 Italian Oncology Departments between March and December 2020 were included. Access rate and temporal intervals between date of symptoms onset and diagnostic and therapeutic services were compared with the same period in 2019. Differences between the 2 years were analyzed using the chi-square test for categorical variables and the Mann-Whitney U test for continuous variables. RESULTS: A slight reduction (-6.9%) in newly diagnosed LC cases was observed in 2020 compared with 2019 (1523 versus 1637, P = 0.09). Newly diagnosed LC pts in 2020 were more likely to be diagnosed with stage IV disease (P < 0.01) and to be current smokers (someone who has smoked more than 100 cigarettes, including hand-rolled cigarettes, cigars, cigarillos, in their lifetime and has smoked in the last 28 days) (P < 0.01). The drop in terms of new diagnoses was greater in the lockdown period (percentage drop -12% versus -3.2%) compared with the other months included. More LC pts were referred to a low/medium volume hospital in 2020 compared with 2019 (P = 0.01). No differences emerged in terms of interval between symptoms onset and radiological diagnosis (P = 0.94), symptoms onset and cytohistological diagnosis (P = 0.92), symptoms onset and treatment start (P = 0.40), and treatment start and first radiological revaluation (P = 0.36). CONCLUSIONS: Our study pointed out a reduction of new diagnoses with a shift towards higher stage at diagnosis for LC pts in 2020. Despite this, the measures adopted by Italian Oncology Departments ensured the maintenance of the diagnostic-therapeutic pathways of LC pts.

Ultrastructural findings of lung injury due to Vaccine-induced Immune Thrombotic Thrombo- cytopenia (VITT) following COVID-19 vaccination: a scanning electron microscopic study.

Vaccine-induced immune thrombotic thrombocytopenia (VITT) is a rare new syndrome occurring after the ChAdOx1 nCoV-19 vaccine immunization. Patients with VITT are characterized by a variable clinical presentation, likewise also the outcome of these patients is very variable. Here we report the lung ultrastructural findings in the course of VITT of a 58-year-old male patient. Alveoli were mainly dilated, irregular in shape, and occupied by a reticular network of fibrin, while interalveolar septa appeared thickened. The proliferation of small capillaries gave rise to plexiform structures and pulmonary capillary hemangiomatosis-like features. Near the alveoli occupied by a dense fibrin network, the medium-sized arteries showed a modified wall and an intraluminal thrombus. This scenario looks quite similar to that found during COVID-19, where the lungs suffer from the attack of the antigen-antibodies complexes and the virus respectively. In both diseases, the final outcome is a severe inflammation, activation of the haemostatic system and fibrinolysis.

Scanning electron microscopy of lung disease due to COVID-19-a case report and a review of the literature

OBJECTIVE: The ongoing Coronavirus pandemic (COVID-19) showed similar characteristics with the severe acute respiratory syndrome (SARS). In the most compromised cases, COVID-19 infection leads to death due to severe respiratory complications. COVID-19-related acute respiratory distress syndrome (ARDS) is the primary cause of death in these patients. In the present study, we show an ultrastructural analysis on the lungs of a patient affected by COVID-19. PATIENTS AND METHODS: Lung specimens obtained at autopsy from a 63-years old patient affected by COVID-19 were fixed in 1% paraformaldehyde. Slices of 300 mu m thickness were dehydrated and dried by Critical Point Drying in CO2. Slices were covered with a conductive gold film approximately 30 nm thick and observed at a Zeiss Sigma 300 SEM FEG in the secondary electron (SE) and backscattered electron (BSE) modes. As case control a lung biopsy from a 60-year-old man was considered. RESULTS: At low power in all COVID-19 lung specimens severe changes in the pulmonary architecture were found, due to the collapse of air spaces. Moreover, alveolar cavities were covered by large membranes. At high power, alveolar membranes showed a fibrillar structure, suggestive of a loose network of fibrin. It has been also found that intra-alveolar red blood cells were frequently present in the alveolar spaces, surrounded by a reticular fibrin network, suggestive for fibrin-hemorrhagic alveolitis. Alveolar changes were constantly associated with pathological features related to the pulmonary vessels. Vascular changes were prominent, including endothelial damage and thrombosis of large pulmonary vessels. Fibrinous microthrombi were frequently detected in the inter-alveolar septal capillaries. In addition, it has been frequently detected capillary proliferation in the alveolar septa with finding suggestive for intussusceptive neo-angiogenesis. CONCLUSIONS: In conclusion, our electron microscopy analysis showed that COVID-19-related lung disease is characterized by a substantial architectural distortion, with the interactions between alveolar and vascular changes. Intra-alveolar hyaline membranes are associated with macro-and micro-thrombotic angiopathy, ending with capillary proliferation. The new blood vessel formation originates from the septa and extends into the surrounding parenchyma. Our findings confirm previous reports on the specificity of the multiple and complex morphological pattern typical, and apparently specific, of COVID-19-related lung disease.

Thrombotic sinusoiditis and local diffuse intrasinusoidal coagulation in the liver of subjects affected by COVID-19: the evidence from histology and scanning electron microscopy.

OBJECTIVE: Liver injury has been reported in patients with COVID-19. This condition is characterized by severe outcome and could be related with the ability of SARS-CoV-2 to activate cytotoxic T cells. The purpose of this study is to show the histological and scanning electron microscopy features of liver involvement in COVID-19 to characterize the liver changes caused by the activation of multiple molecular pathways following this infection. PATIENTS AND METHODS: Liver biopsies from 4 patients (3 post-mortems and 1 in vivo) with COVID-19 were analyzed with histology and by scanning electron microscopy. RESULTS: The liver changes showed significant heterogeneity. The first case showed ground glass hepatocytes and scattered fibrin aggregates in the sinusoidal lumen. The second evidenced intra-sinusoidal thrombi. The third was characterized by sinusoidal dilatation, atrophy of hepatocytes, Disse's spaces dilatation and intra-sinusoidal aggregates of fibrin and red blood cells. The fourth case exhibited diffuse fibrin aggregates in the dilated Disse spaces and microthrombi in the sinusoidal lumen. CONCLUSIONS: In COVID-19-related liver injury, a large spectrum of pathological changes was observed. The most peculiar features were very mild inflammation, intra-sinusoidal changes, including sinusoidal dilatation, thrombotic sinusoiditis and diffuse intra-sinusoidal fibrin deposition. These findings suggested that a thrombotic sinusoiditis followed by a local diffuse intra-vascular (intra-sinusoidal) coagulation could be the typical features of the SARS-CoV-2-related liver injury.

Fetal programming of COVID-19: may the barker hypothesis explain the susceptibility of a subset of young adults to develop severe disease?

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.

Immunohistochemical findings in the lungs of COVID-19 subjects: evidence of surfactant dysregulation.

OBJECTIVE: Acute respiratory distress syndrome (ARDS) is characterized by quantitative and qualitative changes in surfactant composition, leading to surfactant dysregulation with alveolar collapse and acute respiratory hypoxic failure. Recently, surfactant has been hypothesized to play a relevant role in COVID-19, representing a strong defender against SARS-CoV-2 infection. The aim of our work was the study of immunohistochemical surfactant expression in the lungs of patients died following SARS-CoV-2 ARDS, in order to shed light on a possible therapeutic surfactant administration. PATIENTS AND METHODS: We investigated four patients who died due to ARDS following SARS-COV-2 infection and four patients submitted to lung biopsy, in the absence of SARS-CoV-2 infection. In all 8 cases, lung specimens were immunostained with anti-surfactant protein A (SP-A) and B (SP-B). RESULTS: In control subjects, reactivity for SP-B was restricted to type II alveolar cells. Immunostaining for SP-A was observed on the surface of alveolar spaces. In the COVID-19 positive lungs, immunoreactivity for SP-B was similar to that observed in control lungs; SP-A was strongly expressed along the alveolar wall. Moreover, dense aggregates of SP-A positive material were observed in the alveolar spaces. CONCLUSIONS: Our immunohistochemical data show the dysregulation of surfactant production in COVID-19 patients, particularly regarding SP-A expression. The increased presence of SP-A in condensed masses inside alveolar spaces could invalidate the therapeutic efficacy of the treatment with exogenous surfactant.

Trace elements and the carotid plaque: the GOOD (Mg, Zn, Se), the UGLY (Fe, Cu), and the BAD (P, Ca)?

Multiple epidemiological studies have suggested that industrialization and progressive urbanization should be considered one of the main factors responsible for the rising of atherosclerosis in the developing world. In this scenario, the role of trace metals in the insurgence and progression of atherosclerosis has not been clarified yet. In this paper, the specific role of selected trace elements (magnesium, zinc, selenium, iron, copper, phosphorus, and calcium) is described by focusing on the atherosclerotic prevention and pathogenesis plaque. For each element, the following data are reported: daily intake, serum levels, intra/extracellular distribution, major roles in physiology, main effects of high and low levels, specific roles in atherosclerosis, possible interactions with other trace elements, and possible influences on plaque development. For each trace element, the correlations between its levels and clinical severity and outcome of COVID-19 are discussed. Moreover, the role of matrix metalloproteinases, a family of zinc-dependent endopeptidases, as a new medical therapeutical approach to atherosclerosis is discussed. Data suggest that trace element status may influence both atherosclerosis insurgence and plaque evolution toward a stable or an unstable status. However, significant variability in the action of these traces is evident: some - including magnesium, zinc, and selenium - may have a protective role, whereas others, including iron and copper, probably have a multi-faceted and more complex role in the pathogenesis of the atherosclerotic plaque. Finally, calcium and phosphorus are implicated in the calcification of atherosclerotic plaques and in the progression of the plaque toward rupture and severe clinical complications. In particular, the role of calcium is debated. Focusing on the COVID-19 pandemia, optimized magnesium and zinc levels are indicated as important protective tools against a severe clinical course of the disease, often related to the ability of SARS-CoV-2 to cause a systemic inflammatory response, able to transform a stable plaque into an unstable one, with severe clinical complications.

Molecular pathways triggered by COVID-19 in different organs: ACE2 receptor-expressing cells under attack? A review.

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.