Diversity of immune responses in children highly exposed to SARS-CoV-2.

Background: Children are less susceptible than adults to symptomatic COVID-19 infection, but very few studies addressed their underlying cause. Moreover, very few studies analyzed why children highly exposed to the virus remain uninfected. Methods: We analyzed the serum levels of ACE2, angiotensin II, anti-spike and anti-N antibodies, cytokine profiles, and virus neutralization in a cohort of children at high risk of viral exposure, cohabiting with infected close relatives during the lockdown in Spain. Results: We analyzed 40 children who were highly exposed to the virus since they lived with severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2)-infected relatives during the lockdown for several months without taking preventive measures. Of those, 26 reported mild or very mild symptoms. The induced immune response to the virus was analyzed 3 months after the household infection. Surprisingly, only 15 children had IgG anti-S (IgG+) determined by a sensitive method indicative of a past infection. The rest, negative for IgG anti-N or S in various tests, could be further subdivided, according to IgM antibodies, into those having IgM anti-S and IgM anti-N (IgG-IgMhigh) and those having only IgM anti-N (IgG-IgMlow). Interestingly, those two subgroups of children with IgM antibodies have strikingly different patterns of cytokines. The IgMhigh group had significantly higher IFN-α2 and IFN-γ levels as well as IL-10 and GM-CSF than the IgMlow group. In contrast, the IgMlow group had low levels of ACE2 in the serum. Both groups have a weaker but significant capacity to neutralize the virus in the serum than the IgG+ group. Two children were negative in all immunological antibody tests. Conclusions: A significant proportion of children highly exposed to SARS-CoV-2 did not develop a classical adaptive immune response, defined by the production of IgG, despite being in close contact with infected relatives. A large proportion of those children show immunological signs compatible with innate immune responses (as secretion of natural antibodies and cytokines), and others displayed very low levels of the viral receptor ACE2 that may have protected them from the virus spreading in the body despite high and constant viral exposure.

ACE2 Serum Levels as Predictor of Infectability and Outcome in COVID-19.

Background: COVID-19 can generate a broad spectrum of severity and symptoms. Many studies analysed the determinants of severity but not among some types of symptoms. More importantly, very few studies analysed patients highly exposed to the virus that nonetheless remain uninfected. Methods: We analysed serum levels of ACE2, Angiotensin II and anti-Spike antibodies in 2 different cohorts at high risk of viral exposure, highly exposed but uninfected subjects, either high risk health care workers or persons cohabiting with infected close relatives and seropositive patients with symptoms. We tested the ability of the sera of these subjects to neutralize lentivirus pseudotyped with the Spike-protein. Results: We found that the serum levels of ACE2 are significantly higher in highly exposed but uninfected subjects. Moreover, sera from this seronegative persons can neutralize SARS-CoV-2 infection in cellular assays more strongly that sera from non-exposed negative controls eventhough they do not have anti-CoV-2 IgG antibodies suggesting that high levels of ACE2 in serum may somewhat protect against an active infection without generating a conventional antibody response. Finally, we show that among patients with symptoms, ACE2 levels were significantly higher in infected patients who developed cutaneous as compared with respiratory symptoms and ACE2 was also higher in those with milder symptoms. Conclusions: These findings suggest that soluble ACE2 could be used as a potential biomarker to predict SARS-CoV-2 infection risk and to discriminate COVID-19 disease subtypes.

Creación de un cuestionario de clima organizacional para hospitales de alta complejidad, Chile / Creation of a Questionnaire of Organizational Climate for Hospitals of High Complexity, Chile / Criação de um questionário de clima organizacional para hospitais de alta complexidade, Chile

En el contexto de un sector salud chileno en proceso de transformaciones, se propuso crear un cuestionario validado para medir el clima organizacional en hospitales de alta complejidad. Para su formulación se identificaron dimensiones y variables de diversos autores y se revisaron diferentes cuestionarios, validaciones y constructos utilizados en diferentes propuestas a nivel internacional. La investigación es de tipo descriptivo, cuantitativo e inferencial y se realizó sobre una base de datos de 561 empleados hospitalarios, a quienes se les aplicó un cuestionario por la vía de una entrevista personalizada en el lugar de trabajo, que consta de 71 variables agrupadas en 14 dimensiones. La aplicación del instrumento, así como los estudios de validez y de confiabilidad, permitieron dar origen a un nuevo cuestionario validado que cuenta con 10 factores y 44 reactivos de alta confiabilidad, que explican el 52,181% de la varianza total, alcanzando un alfa de Cronbach total de 0,89.

In the context of a Chilean health sector undergoing a process of transformations, it was proposed to create a validated questionnaire to measure the organizational climate in high complexity hospitals. In order to prepare it, dimensions and variables by diverse authors were identified and diverse questionnaires, validations and constructs used in different proposals at the international level were reviewed. The research is descriptive, quantitative and inferential and it was conducted on a database of 561 hospital employees, to whom a questionnaire was applied, through a personalized interview at their work place, consisting of 71 variables grouped in 14 dimensions. The application of the instrument, as well as the validity and reliability studies, allowed giving origin to a new validated questionnaire with 10 factors and 44 high-reliability reagents that explain 52.181 % of the total variance, reaching a total Cronbach's alpha 0.89.

No contexto de um processo de transformações do setor saúde chileno, propõe-se criar um questionário validado para medir o clima organizacional em hospitais de alta complexidade. Para sua formulação dimensões e variáveis de diversos autores foram identificadas e se revisaram diferentes questionários, validações e construtos utilizados em diferentes propostas do nível internacional. A pesquisa é de tipo descritivo, quantitativo e inferencial e foi realizado sobre uma base de dados de 561 funcionários hospitalares, a quem foi aplicado questionário pela via de entrevista pessoalizada no local de trabalho, que consta de 71 variáveis agrupadas em 14 dimensões. A aplicação do instrumento, bem como os estudos de validez e confiabilidade, permitiu dar origem a um novo questionário validado que conta com 10 fatores e 44 reagente de alta confiabilidade, que explicam o 52,181% da variância total, atingindo um alfa de Cronbach total de 0,89.

Post-ischemic estradiol treatment reduced glial response and triggers distinct cortical and hippocampal signaling in a rat model of cerebral ischemia.

BACKGROUND: Estradiol has been shown to exert neuroprotective effects in several neurodegenerative conditions, including cerebral ischemia. The presence of this hormone prior to ischemia attenuates the damage associated with such events in a rodent model (middle cerebral artery occlusion (MCAO)), although its therapeutic value when administered post-ischemia has not been assessed. Hence, we evaluated the effects of estradiol treatment after permanent MCAO (pMCAO) was induced in rats, studying the PI3K/AKT/GSK3/ß-catenin survival pathway and the activation of SAPK-JNK in two brain areas differently affected by pMCAO: the cortex and hippocampus. In addition, we analyzed the effect of estradiol on the glial response to injury. METHODS: Male rats were subjected to pMCAO and estradiol (0.04 mg/kg) was administered 6, 24, and 48 h after surgery. The animals were sacrificed 6 h after the last treatment, and brain damage was evaluated by immunohistochemical quantification of 'reactive gliosis' using antibodies against GFAP and Iba1. In addition, Akt, phospho-Akt(Ser473), phospho-Akt(Thr308), GSK3, phospho-GSK3(Ser21/9), ß-catenin, SAPK-JNK, and pSAPK-JNK(Thr183/Tyr185) levels were determined in western blots of the ipsilateral cerebral cortex and hippocampus, and regional differences in neuronal phospho-Akt expression were determined by immunohistochemistry. RESULTS: The increases in the percentage of GFAP- (5.25-fold) and Iba1- (1.8-fold) labeled cells in the cortex and hippocampus indicate that pMCAO induced 'reactive gliosis'. This effect was prevented by post-ischemic estradiol treatment; diminished the number of these cells to those comparable with control animals. pMCAO down-regulated the PI3K/AkT/GSK3/ß-catenin survival pathway to different extents in the cortex and hippocampus, the activity of which was restored by estradiol treatment more efficiently in the cerebral cortex (the most affected region) than in the hippocampus. No changes in the phosphorylation of SAPK-JNK were observed 54 h after inducing pMCAO, whereas pMCAO did significantly decrease the phospho-Akt(Ser473) in neurons, an effect that was reversed by estradiol. CONCLUSION: The present study demonstrates that post-pMCAO estradiol treatment attenuates ischemic injury in both neurons and glia, events in which the PI3K/AKT/GSK3/ß-catenin pathway is at least partly involved. These findings indicate that estradiol is a potentially useful treatment to enhance recovery after human ischemic stroke.