Pathophysiological insights from lung diffusing capacity for nitric monoxide (DLNO) after COVID-19

Background: Gas exchange abnormalities in COVID-19 survivors might involve impairment of the transfer through alveolar-capillary membrane and/or loss of capillary bed. Membrane diffusing capacity (Dm) and capillary volume (Vc) can be calculated from combined DLCO-DLNO. Aim(s): To investigate the values of Dm and Vc after COVID-19. Method(s): We retrospectively included all the patients (Pts) having performed DLCO-DLNO after COVID-19 in 4 French centres between 2020/04/20 and 2021/12/16. We excluded Pts with known history of COPD, severe asthma, interstitial lung disease, pulmonary hypertension, and congestive heart failure. We collected data from clinical records, pulmonary function test (PFT), and CT-scan when performed +/-1.5 months from PFT. Result(s): Data from 132 Pts have been analysed yet (over a total of about 500): 72 men (55%), mean age 57.7+/-13 years, mean BMI 30+/-5.7. 25 Pts (19%) were grade 1-4 on COVID-19 WHO scale (no oxygen), 45 (34%) were grade 5 (oxygen), 44 (33%) were grade 6 (NIV or high-flow oxygen), and 18 (14%) were grade 7-9 (mechanical ventilation). Median time between COVID-19 and PFT was 4.4 months [3.1-6.1]. 58 Pts (44%) had DLCO < lower limit of normal (LLN), with a significant correlation between initial COVID-19 severity and later DLCO. Mean Dm and Vc were 48.7% +/-15.1 and 80.2% +/-21. The most frequent pattern was Dm < LLN and normal Vc, in 78 Pts (59%). Only 1 (1%) had isolated Vc < LLN with normal Dm. Among the 37 (28%) with both Dm and Vc < LLN, 36 performed a CT-scan that showed fibrosing sequellae in 26 (72%). Conclusion(s): Dm was the most decreased variable, suggesting delayed healing after COVID-19. Decreased Vc was frequently associated with pulmonary fibrosis.

Marcadores De Endoteliopatias Continuamente Elevados Apos a Alta Hospitalar Por Covid-19 Relacionados Ao Tempo De Internacao Dos Pacientes

Objetivo: Avaliar se os marcadores de endoteliopatias continuamente elevados apos a alta hospitalar por COVID-19 possui correlacao com o tempo de internacao dos pacientes. Materiais e Metodos: Foram recrutados 97 pessoas sobreviventes de COVID-19 com a infeccao confirmada pelo ensaio de RT-PCR (PCR real time) de 18 a 65 anos internadas na unidade de terapia intensiva de dois grandes hospitais de referencia regionais. Os voluntarios dos tres grupos estavam curados ha pelo menos 30 dias da convocacao. Todos assinaram o Termo de Consentimento Livre Esclarecido (TCLE) e a pesquisa foi aprovada pelo Comite de Etica da Universidade Federal do Espirito Santo, sob numero CAAE 37094020.6.0000.5060. A infeccao pelo SARS-CoV-2 precedeu a vacinacao completa dos pacientes estudados (considerando 2 doses minimas). Os participantes responderam um formulario no RedCap e os dados relacionados a internacao foram adquiridos junto aos hospitais. Foram analisados dois marcadores que podem indicar a endoteliopatia: Fator de von Willebrand Antigeno (FvW:Ag) e D-dimero (DD). O teste de multipla regressao linear foi usado para estabelecer a diferenca entre o tempo de internacao e os parametros avaliados e foi considerado significativa p < 0,05. Resultados: Pacientes com o FvW:Ag e FVIII >150% apos a alta tiveram a media do tempo de internacao de 12 dias e mediana de 10 dias, em contrapartida, pacientes com niveis normais de FvW:Ag e FVIII internaram em media 10 dias e a mediana foi de 8 dias, p=0,0536 e p=0,1539 respectivamente. Os pacientes com o DD >500 mg/dL apos a alta tiveram a media do tempo de Internacao de 11,6 dias e mediana de 10 dias, os pacientes com niveis normais de DD internaram em media 10,75 dias e a mediana 8 dias, p < 0,0001. Discussao: Os marcadores de endoteliopatias FvW:Ag, FVIII e DD demonstraram em um estudo anterior desse mesmo grupo de pesquisa diferenca significativa quando comparados ao grupo controle de participantes que tambem tiveram COVID-19 a nivel ambulatorial (p < 0,05), indicando que esses marcadores permanecem alterados significantemente em pacientes que internaram na UTI apos a alta hospitalar. Varios estudos apontaram os marcadores avaliados nesse trabalho como possivelmente alterados na fase aguda da COVID-19, predizendo a forma grave da doenca. Nao foi estabelecido apos uma analise multivariada uma correlacao entre o FvW:Ag e FVIII continuamente alterados apos a alta hospitalar e o tempo em que os pacientes ficaram internados. Entretanto, o DD alterado apos a alta demonstrou correlacao positiva com o aumento do tempo de internacao dos pacientes, corroborando com outros estudos. Conclusao: A endoteliopatia por infeccao endotelial direta com SARS-CoV-2 e os danos indiretos causados pela inflamacao desempenham o papel predominante no desenvolvimento e agravamento da COVID-19. As consequencias do desbalanceamento do sistema pro e anti trombotico estao relacionados com o tempo de internacao dos pacientes. A COVID-19 longa, na fase pos-aguda, e uma sindrome caracterizada pela persistencia dos sintomas clinicos alem de quatro semanas do inicio dos sintomas agudos e pode estar associada a resquicios da endoteliopatia causada pela infeccao. Copyright © 2022

Marcadores Inflamatorios Endoteliais E Plasmaticos Apos a Alta Hospitalar Por Covid-19

Objetivo: Avaliar os niveis de marcadores inflamatorios endoteliais e plasmaticos em pacientes apos a alta da internacao por COVID-19. Materiais e Metodos: Foram recrutados 226 pessoas diagnosticadas com a COVID-19 confirmadas pelo ensaio de RT-PCR (PCR real time) de 18 a 65 anos, divididos em tres grupos: controle ambulatorial (Grupo A, n=82), enfermaria (Grupo B, n=47) e UTI (Grupo C, n=97). Os voluntarios dos tres grupos estavam curados ha pelo menos 30 dias da convocacao. Todos assinaram o Termo de Consentimento Livre Esclarecido (TCLE) e a pesquisa foi aprovada pelo Comite de Etica da Universidade Federal do Espirito Santo, sob numero CAAE 37094020.6.0000.5060. A infeccao pelo SARS-CoV-2 precedeu a vacinacao completa dos pacientes estudados (considerando 2 doses minimas). Foram dosados os seguintes marcadores: Fator de von Willebrand Ag (FvWAg), D-dimero (DD), Fator VIII (FVIII), Fibrinogenio (FIB), Hemoglobina glicada (HbA1c), Interleucina-6 (IL-6) e Fator de Necrose Tumoral alfa (TNF-alpha). O teste de multiplas comparacoes Dunn's foi usado para estabelecer a diferenca entre os grupos e foi considerado significativa p<0,05. Resultados: FVIII: Grupo A (Amb) vs. Grupo B (Enf) = p>0,9999 e Grupo A vs. Grupo C (UTI), p=0,0789. FvWAg: Grupo A vs. Grupo B, p=0,8277 e Grupo A vs. Grupo C, p=0,0361. DD: Grupo A vs. Grupo B, p=0,2090 e Grupo A vs. Grupo C, p=0,0010. HbA1c: Grupo A vs. Grupo B, p=0,2680 e Grupo A vs. Grupo C, p<0,0001. FIB: Grupo A vs. Grupo B, p>0,9999 e Grupo A vs. Grupo C, p=0,3363. IL-6: Grupo A vs. Grupo B, p>0,9999 e Grupo A vs. Grupo C, p>0,9999. TNF-alpha: Grupo A vs. Grupo B, p>0,9999 e Grupo A vs. Grupo C, p=0,4149. Discussao: Os Grupos A e B nao obtiveram diferenca significante (p<0,05) nos parametros avaliados. Os pacientes do Grupo C quando comparados ao Grupo A demonstraram uma diferenca significativa apenas nas dosagens de FvWAg, HbA1c e DD. Varios estudos apontaram os marcadores avaliados nesse trabalho como possivelmente alterados na fase aguda da COVID-19, predizendo a forma grave da doenca. Niveis sericos de IL-6 e TNF-alpha apos a alta nao divergiram entre os grupos estudados, indicando nesse trabalho que os niveis pre ou pos COVID-19 desse marcador nao estao relacionados com a resposta adversa obtida no Grupo C. Uma correlacao positiva entre o FvWAg e o DD favorece um mau prognostico, e isso sustenta o desequilibrio entre os processos pro e anticoagulantes diretamente relacionados a disfuncao endotelial em pacientes com COVID-19 que foram internados na UTI. A transformacao da inflamacao em fibrose tecidual, remodelacao vascular envolvida em hipoxia, dano de celulas endoteliais vasculares, estado de hipercoagulabilidade, e mudancas continuas nos marcadores plasmaticos contribuem para a lesao pulmonar pos-alta. Conclusao: Alteracoes vasculares sao preditivos relevantes para a mortalidade hospitalar. O retorno a normalidade dos marcadores depois de no minimo 30 dias apos a infeccao e um bom prognostico para eventos similares futuros. A permanencia das alteracoes apos a alta hospitalar do grupo C (UTI) pode indicar alteracoes pre-existentes nesse grupo (como Doencas cardiovasculares e pulmonares), aumento na quantidade de sequelas pos infeccao pelo SARS-CoV-2, bem como predisposicao a novos agravamentos considerando o estado continuo de lesao vascular. Copyright © 2022

Gut microbial indicators of metabolic health underlie age-related differences in obesity and diabetes risk among Native Hawaiians and Pacific Islanders.

Native Hawaiians and Pacific Islanders (NHPIs) suffer from higher prevalence of and mortality to type 2 diabetes mellitus (T2DM) than any other major race/ethnic group in Hawaii. Health inequities in this indigenous population was further exacerbated by the SARS-CoV-2 pandemic. T2DM progression and medical complications exacerbated by COVID-19 are partially regulated by the gut microbiome. However, there is limited understanding of the role of gut bacteria in the context of inflammation-related diseases of health disparities including T2DM and obesity. To address these gaps, we used a community-based research approach from a cohort enriched with NHPI residents on the island of Oahu, Hawaii (N=138). Gut microbiome profiling was achieved via 16s rDNA metagenomic sequencing analysis from stool DNA. Gut bacterial capacity for butyrate-kinase (BUK)-mediated fiber metabolism was assessed using quantitative PCR to measure the abundance of BUK DNA and RNA relative to total bacterial load per stool sample. In our cohort, age positively correlated with hemoglobin A1c (%; R=0.39; P<0.001) and body mass index (BMI; R=0.28; P<0.001). The relative abundance of major gut bacterial phyla significantly varied across age groups, including Bacteroidetes (P<0.001), Actinobacteria (P=0.007), and Proteobacteria (P=0.008). A1c was negatively correlated with the relative levels of BUK DNA copy number (R=-0.17; P=0.071) and gene expression (R=-0.33; P=0.003). Interestingly, we identified specific genera of gut bacteria potentially mediating the effects of diet on metabolic health in this cohort. Additionally, α-diversity among gut bacterial genera significantly varied across T2DM and BMI categories. Together, these results provide insight into age-related differences in gut bacteria that may influence T2DM and obesity in NHPIs. Furthermore, we observed overlapping patterns between gut bacteria and T2DM risk factors, indicating more nuanced, interdependent interactions among these factors as partial determinants of health outcomes. This study adds to the paucity of NHPI-specific data to further elucidate the biological characteristics associated with pre-existing health inequities in this racial/ethnic group that is significantly underrepresented in biomedical research.

A crystallographic snapshot of SARS-CoV-2 main protease maturation process

SARS-CoV-2 is the causative agent of COVID-19. The dimeric form of the viral Mpro is responsible for the cleavage of the viral polyprotein in 11 sites, including its own N- and C-terminus. The lack of structural information for intermediary forms of Mpro is a setback for the understanding its self-maturation process. Herein, we used X-ray crystallography combined with biochemical data to characterize multiple forms of SARS-CoV-2 Mpro. For the immature form, we show that extra N-terminal residues caused conformational changes in the positioning of domainthree over the active site, hampering the dimerization and diminishing its activity. We propose that this form preludes the cis and trans-cleavage of N-terminal residues. Using fragment screening, we probe new cavities in this form which can be used to guide therapeutic development. Furthermore, we characterized a serine site-directed mutant of the Mpro bound to its endogenous Nand C-terminal residues during dimeric association stage of the maturation process. We suggest this form is a transitional state during the C-terminal trans-cleavage. This data sheds light in the structural modifications of the SARS-CoV-2 main protease during its self-maturation process.

Mortality due to respiratory infections: an alert study before COVID-19 pandemic.

Objective: Respiratory tract infections remain a common problem in clinical practice with high morbidity and mortality worldwide. In Portugal, pneumonia was the third leading death cause in 2018. Due to COVID-19 pandemic, there is a growing concern about the burden of respiratory diseases and preventable risk factors. The present study started before the pandemic and its aim was to determine the occurrence of pneumonia/bronchopneumonia in a postmortem series and to characterize its circumstantial context. Methods: A retrospective anatomopathological study was performed on cases with acute pneumonia/bronchopneumonia at the Medicolegal Portuguese Institute (2011-2017). Results: In an autopsy series of 737 patients, 521 were male and 675 presented comorbidities. The mean age was 63.87 ± 19.8 years. The most common acquisition site was community (65.1%), as natural death (65.5%). Concerning the manner of death, most cases (48.0%) were sudden deaths, followed by accidents (29.2%). A statistically significant association was observed between the medicolegal etiology and the place of infection acquisition, with higher prevalence of natural obitus (91.0%) in community-acquired pneumonia/bronchopneumonia versus higher prevalence of violent obitus in hospital-acquired pneumonia/bronchopneumonia (82.1%) (p < 0.001). Conclusions: Forensic anatomopathological postmortem data may contribute to better understand community and hospital pulmonary infections.

CARACTERÍSTICAS EPIDEMIOLÓGICAS DA HANSENÍASE NO BRASIL ENTRE OS ANOS DE 2015 E 2020

Introdução/Objetivos: A hanseníase é uma doença infecciosa causada pelo Mycobacterium leprae. No Brasil, é um importante problema de saúde pública, sendo de notificação compulsória e investigação obrigatória. O objetivo deste trabalho é analisar os casos de hanseníase notificados e relacionar a prevalência com características sócio-econômicas. Metodologia: Dados referentes às notificações de hanseníase, publicados no SINAN-DATASUS (Doenças e Agravos de Notificação), entre 2015 a 2020, foram tabulados, analisados, e comparados com os publicados em trabalhos científicos relacionados ao tema. Resultados: Entre os anos de 2015 e 2020 foram notificados 195.429 casos de hanseníase no Brasil. As maiores notificações ocorreram em 2018 (20,45%). As regiões Nordeste (42,3%), Centro-Oeste (21,2%), e Norte (14,4%) se destacam. As maiores prevalências foram observadas nas regiões Centro-Oeste (52,3/100.000 hab) e Norte (41,8/100.000 hab), em 2018. A região Sul apresentou o menor número de notificações (3,24%), bem como, a menor prevalência (2,1/100.000 hab, em 2020). A análise da distribuição dos casos por ano demonstra uma importante queda em 2020. A região Norte, por exemplo, apresentou queda de 46% entre 2019 e 2020, passando de 38,1/100.000 hab para 20/100.000 hab. A pandemia de COVID-19, bem como, as medidas de isolamento implantadas para seu controle, podem ter refletido na menor busca por atendimentos em saúde. Análise de casos por sexo demostra predominância do sexo masculino em todos as regiões e anos analisados. A hanseníase é considerada uma doença negligenciada, sendo esse conceito atribuído às doenças de maior ocorrência em países em desenvolvimento. Condições de vida precárias, pobreza, baixa escolaridade e fome são fatores de risco. Além disso, diferentes trabalhos associam a endemicidade de hanseníase à migração populacional. A baixa renda per capita das regiões Norte e Nordeste, bem como, dados referentes à pobreza podem explicar a alta prevalência de hanseníase nessas regiões. Movimentos migratórios associados ao crescimento econômico, ocorrido em cidades da região Centro Oeste, nos últimos anos, também são responsáveis pela sua endemicidade. Conclusão: Podemos concluir que, embora o tratamento preconizado para hanseníase seja disponibilizado no SUS e, o mesmo seja eficaz, sua prevalência ainda não apresenta uma queda satisfatória. Regiões com baixa renda per capita e cidades que apresentaram alterações demográficas importantes, são endêmicas.

Apport de la technique de double diffusion DLCO-DLNO dans l’évaluation des séquelles fonctionnelles respiratoires post-COVID

Introduction La COVID-19 peut être responsable d’une pneumonie sévère pouvant entraîner une fibrose séquellaire, mais présente également un tropisme vasculaire. L’objectif principal de cette étude était de décrire les parts respectives d’altération du facteur membranaire (Dm) et du volume capillaire pulmonaire (Vc) dans les suites d’une COVID-19, à l’aide de la technique de double diffusion DLCO-DLNO. Méthodes Étude rétrospective observationnelle monocentrique. Tous les patients majeurs ayant réalisé une EFR avec double diffusion dans le cadre d’une réévaluation post-COVID au CHU Avicenne entre le 20/04/2020 et le 24/08/2021 étaient éligibles. Ont été exclus les patients avec BPCO, PID, HTAP préexistante. Les données cliniques ont été recueillies, la première EFR de réévaluation et la TDM thoracique si réalisée à±1 mois des EFR. Résultats Au total, 41 hommes et 29 femmes ont été inclus (59 %/41 %), d’âge moyen 58,2 ans±13,3 et d’IMC 30,1±6,5 (Tableau 1). Ils ont été divisés en 3 groupes selon la sévérité de l’épisode initial : COVID-19 ambulatoire (groupe 1 ;n=18), hospitalisation en salle (groupe 2 ;n=24), hospitalisation en soins intensifs (groupe 3 ;n=28). L’EFR a été réalisée en moyenne 5,2 mois±2,9 après la COVID-19. La fonction était significativement plus altérée au sein du groupe 3 : 14 patients (20 %) présentaient un trouble ventilatoire restrictif, dont 12 appartenaient au groupe 3 ;26 patients (37 %) avaient une DLCO<limite inférieure de la normale, dont 22 appartenaient au groupe 3. Sur l’ensemble de la cohorte, les Dm et VC moyens étaient : 45,4 %±13,9 et 80,2 %±23 (Tableau 1). Le profil le plus fréquent était une altération isolée du Dm (38 patients ;54 %). Aucune altération isolée du Vc n’a été observée. Parmi 22 patients avec diminution des 2 variables, 20 avaient réalisé une TDM : 12 présentaient des signes de fibrose d’étendue>5 % avec bronchectasies par traction, 4 des réticulations sous-pleurales et 4 du verre dépoli. Conclusion Le Dm était la variable fonctionnelle la plus altérée. Elle peut être diminuée malgré une DLCO normale. Ce profil évoque préférentiellement un mécanisme de cicatrisation longue, y compris pour des COVID-19 initialement peu sévères. L’altération du Vc était fréquemment associée à une fibrose séquellaire. Cette étude va se poursuivre en incluant des patients supplémentaires, afin de décrire l’évolution longitudinale chez les patients ayant réalisé plusieurs mesures, et d’étudier les corrélations avec les autres variables fonctionnelles et avec les images de la TDM thoracique.

A Crystallographic Snapshot of SARS-CoV-2 Main Protease Maturation Process.

SARS-CoV-2 is the causative agent of COVID-19. The dimeric form of the viral Mpro is responsible for the cleavage of the viral polyprotein in 11 sites, including its own N and C-terminus. The lack of structural information for intermediary forms of Mpro is a setback for the understanding its self-maturation process. Herein, we used X-ray crystallography combined with biochemical data to characterize multiple forms of SARS-CoV-2 Mpro. For the immature form, we show that extra N-terminal residues caused conformational changes in the positioning of domain-three over the active site, hampering the dimerization and diminishing its activity. We propose that this form preludes the cis and trans-cleavage of N-terminal residues. Using fragment screening, we probe new cavities in this form which can be used to guide therapeutic development. Furthermore, we characterized a serine site-directed mutant of the Mpro bound to its endogenous N and C-terminal residues during dimeric association stage of the maturation process. We suggest this form is a transitional state during the C-terminal trans-cleavage. This data sheds light in the structural modifications of the SARS-CoV-2 main protease during its self-maturation process.

Who Should Get Vaccinated First? An effective Network Information-driven Priority Vaccination Strategy (preprint)

Approval of emergency use of the Novel Coronavirus Disease 2019 (COVID-19) vaccines in many countries has brought hope to ending the COVID-19 pandemic sooner. Considering the limited vaccine supply in the early stage of COVID-19 vaccination programs in most countries, a highly relevant question to ask is: who should get vaccinated first? In this article we propose a network information- driven vaccination strategy where a small number of people in a network (population) are categorized, according to a few key network properties, into priority groups. Using a network-based SEIR model for simulating the pandemic progression, the network information-driven vaccination strategy is compared with a random vaccination strategy. Results for both large-scale synthesized networks and real social networks have demonstrated that the network information-driven vaccination strategy can significantly reduce the cumulative number of infected individuals and lead to a more rapid containment of the pandemic. The results provide insight for policymakers in designing an effective early-stage vaccination plan.