Younger age is associated with cardiovascular pathological phenotype of severe COVID-19 at autopsy.

Introduction: COVID-19 affects patients of all ages. There are few autopsy studies focusing on the younger population. We assessed an autopsy cohort aiming to understand how age influences pathological outcomes in fatal COVID-19. Methods: This study included autopsied patients, aged 6 months to 83 years, with confirmed COVID-19 in 2020-2021. We collected tissue samples from deceased patients using a minimally invasive autopsy protocol and assessed pathological data following a systematic approach. Results: Eighty-six patients were included, with a median age of 55 years (IQR 32.3-66.0). We showed that age was significantly lower in patients with acute heart ischemia (p = 0.004), myocarditis (p = 0.03) and lung angiomatosis (p < 0.001), and significantly higher in patients with exudative diffuse alveolar damage (p = 0.02), proliferative diffuse alveolar damage (p < 0.001), lung squamous metaplasia (p = 0.003) and lung viral atypia (p = 0.03), compared to patients without those findings. We stratified patients by their age and showed that cardiovascular findings were more prevalent in children and young adults. We performed principal component analysis and cluster of pathological variables, and showed that cardiovascular variables clustered and covariated together, and separated from pulmonary variables. Conclusion: We showed that age modulates pathological outcomes in fatal COVID-19. Younger age is associated with cardiovascular abnormalities and older age with pulmonary findings.

Perivascular clusters of Th2 cells and M2 macrophages in allergic contact dermatitis to methylchloroisothiazolinone and methylisothiazolinone.

BACKGROUND: Methylisothiazolinone (MI) and Methylchloroisothiazolinone (MCI) are among the most common skin sensitizers, yet the immunological events that occur during MCI/MI allergic contact dermatitis (ACD) are still poorly understood. OBJECTIVES: To analyse dendrocytes, macrophage subtypes and T cells in skin during the elicitation phase of MCI/MI ACD. METHODS: Thirteen patients with positive patch test reactions to MCI/MI (ACD group) and 11 individuals with negative patch test results were selected. Skin biopsies were only performed at 48 hours of patch testing. Immunohistochemistry was conducted to assess T cells, dendrocytes (Factor XIIIa), M1 (p-Stat1, CD68) and M2 (c-Maf, CD163) macrophages. Transcriptional analyses were performed for cytokines and related factors, and further compared to atopic dermatitis samples (n=4). Immunofluorescence assays addressed T cells location, along with IL-4 or IL-13, within the skin. RESULTS: MCI/MI elicited dermal dendrocytes and macrophages, pronouncedly the M2 subtype. T cells, majorly CD4+ T cells, accumulated in the perivascular areas. Similarly, abundant IL-4 protein was detected in these areas. There was an upregulation of IL-4 and IL-13 mRNA expression, a mild increase in IFNG mRNA levels and a down-regulation of RORC in the ACD group. Immunofluorescence revealed dermal clusters of T cells co-localized with IL-4. CONCLUSIONS: M2 macrophages and Th2 cells participate in the immunopathogenesis of MCI/MI ACD. Dermal dendrocytes and M2 macrophages may assist the formation of CD4+ T cells perivascular clusters. These findings render a mechanistic insight into the MCI/MI reaction. Further analysis at different timepoints of patch testing is required to fully comprehend this ACD kinetics.

Evidence of bone marrow downregulation in brain-dead rats.

Experimental findings support the evidence of a persistent leucopenia triggered by brain death (BD). This study aimed to investigate leucocyte behaviour in bone marrow and blood after BD in rats. BD was induced using intracranial balloon catheter inflation. Sham-operated (SH) rats were trepanned only. Thereafter bone marrow cells were harvested every six hours from the femoral cavity and used for total and differential counts. They were analysed further by flow cytometry to characterize lymphocyte subsets, granulocyte adhesion molecules expression and apoptosis/necrosis [annexin V/propidium iodide (PI) protocol]. BD rats exhibited a reduction in bone marrow cells due to a reduction in lymphocytes (40%) and segmented cells (45%). Bone marrow lymphocyte subsets were similar in BD and SH rats (CD3, P = 0.1; CD4, P = 0.4; CD3/CD4, P = 0.4; CD5, P = 0.4, CD3/CD5, P = 0.2; CD8, P = 0.8). Expression of L-selectin and beta2 -integrins on granulocytes did not differ (CD11a, P = 0.9; CD11b/c, P = 0.7; CD62L, P = 0.1). There were no differences in the percentage of apoptosis and necrosis (Annexin V, P = 0.73; PI, P = 0.21; Annexin V/PI, P = 0.29). In conclusion, data presented suggest that the downregulation of the bone marrow is triggered by brain death itself, and it is not related to changes in lymphocyte subsets, granulocyte adhesion molecules expression or apoptosis and necrosis.

Periprostatic innervation: New issues based on segmental analysis of 10 human cadaver pelvic blocs.

BACKGROUND: The exact paths of periprostatic nerves have been under debate over the last decades. In the present study, the topographic distribution of nerves around the prostate and their relative distances from the prostatic capsule were analyzed in male cadaver visceral blocs. METHODS: The pelvic organs from ten fresh male cadavers were removed and serial sectioned en bloc for histological investigation. The macroslices was divided into four sectors. Each sector was centrally covered with a raster dividing each sector in three subsectors numbered clockwise. The prostatic capsule was identified, and distances of 2.5 and 5 mm from the prostate were demarked with lines. We quantified the number of nerve fibers present in each subsector of each slide and recorded their position relative to the prostatic capsule. RESULTS: In general, the topographic analysis revealed that the majority of nerves were identified in sectors 4 through 9, corresponding to the posterolateral and posterior surfaces of the prostate gland. At the prostate base, the majority of nerves were found at the posterolateral and posterior surfaces of the gland. Within the mid-region of the prostate, the same topographic distribution pattern was observed, but the nerve fibers were closer to the prostatic capsule. At the apical region, the percentage of nerve fibers identified in the anterior region was higher, despite their major concetration in the posterior surface. The nerves identified at the apex were mainly located up to 2.5 mm from the prostate. This proximity to the prostate was specifically observed in the anterolateral and anterior sectors. In the craniocaudal sense, the percentage of nerves identified between 2.5 and 5 mm from the prostatic capsule remained constant. CONCLUSIONS: A significant number of nerve fibers were present in the anterior and anterolateral positions, especially at the apex. The anterior nerves were closer to the prostate. This proximity suggests that the anterior nerves may participate in local physiology and that the cavernous nerves are probably formed by the posterior nerve fibers. It is likely that the safe distance of 2.5 mm from all surfaces of the prostate may be related to cavernous fiber preservation.

Stress amplifies lung tissue mechanics, inflammation and oxidative stress induced by chronic inflammation.

BACKGROUND: Mechanisms linking behavioral stress and inflammation are poorly understood, mainly in distal lung tissue. OBJECTIVE: We have investigated whether the forced swim stress (FS) could modulate lung tissue mechanics, iNOS, cytokines, oxidative stress activation, eosinophilic recruitment, and remodeling in guinea pigs (GP) with chronic pulmonary inflammation. METHODS: The GP were exposed to ovalbumin or saline aerosols (2×/wk/4wks, OVA, and SAL). Twenty-four hours after the 4th inhalation, the GP were submitted to the FS protocol (5×/wk/2wks, SAL-S, and OVA-S). Seventy-two hours after the 7th inhalation, lung strips were cut and tissue resistance (Rt) and elastance (Et) were obtained (at baseline and after OVA and Ach challenge). Strips were submitted to histopathological evaluation. RESULTS: The adrenals' weight, the serum cortisol, and the catecholamines were measured. There was an increase in IL-2, IL-5, IL-13, IFN-γ, iNOS, 8-iso-PGF2α, and in %Rt and %Et after Ach challenge in the SAL-S group compared to the SAL one. The OVA-S group has had an increase in %Rt and %Et after the OVA challenge, in %Et after the Ach and in IL-4, 8-iso-PGF2α, and actin compared to the OVA. Adrenal weight and cortisol serum were increased in stressed animals compared to nonstressed ones, and the catecholamines were unaltered. CONCLUSION & CLINICAL RELEVANCE: Repeated stress has increased distal lung constriction, which was associated with an increase of actin, IL-4, and 8-iso-PGF2α levels. Stress has also induced an activation of iNOS, cytokines, and oxidative stress pathways.

Inflammation and remodeling in infantile, juvenile, and adult allergic sensitized mice.

BACKGROUND: Airway structural changes occur early in childhood asthma, but it is unknown whether the development of airway alterations in children is similar to that of adults. We compared inflammation and remodeling parameters in allergic sensitized infantile, juvenile, and adult mice. METHODS: Infantile mice (18D) were sensitized with three intraperitoneal injections (i.p.) of ovalbumin (OVA) at days 5 and 7 and challenged with OVA at days 14-16. The 18D1 group received an additional challenge at days 9-11. The juvenile mice (40D) received challenges at days 22-24 and 36-38. Adult mice (100D) were sensitized at days 60-62 and received three inhalations at days 77-79 and 96-98. Animals were submitted to whole body plethysmography. Airway eosinophils, CD3+ T-lymphocytes, IL-5+ cells, mucus content, collagen and reticular fibers density, and smooth muscle thickness were quantified. RESULTS: All sensitized animals presented with airway hyperresponsiveness, without differences in eosinophil cell density. The density of CD3+ T-cells was higher in the 100D and 18D1 groups than in the 18D and 40D groups. Infantile sensitized groups demonstrated increased interleukin-5 expression in the airways. Infantile mice demonstrated more mucus in the bronchiolar epithelium than the 40D and 100D mice. The 18D animals demonstrated less collagen than the 18D1 group. Juvenile and adult mice had increased airway smooth muscle thickness when compared to age-matched controls, but no differences were observed in the infantile groups. CONCLUSION: We have shown that infantile mice develop inflammatory and structural alterations in the airways that are partially different from those developed in older animals.

Characterization of autopsy-proven fatal asthma patients in São Paulo, Brazil.

Few data are available on autopsy-proven fatal asthma patients in São Paulo, Brazil. We characterized 73 asthma patients who were autopsied at the Serviço de Verificação de Obitos da Universidade de São Paulo between 1996 and 2004. An interview with the next of kin assessed socioeconomic status, history, and treatment of asthma. There were 42 women and 31 men. Fifty-six (76.7%) of them were older than 34 years. Sixty-three percent were Caucasians, 77.3% had < 8 years of schooling, and the median income was 1.6 times the minimum wage. Twenty-two patients (30.1%) were smokers and 14 (19.2%) were ex-smokers. Only 25 (34.2%) patients were regularly followed by a doctor. Only 12.3% received inhaled steroids. Thirty-five patients (47.9%) had moderate-to-severe asthma. Fifty-five (75.3%) deaths took place outside a hospital. We conclude that this population shares characteristics of severe or poorly controlled asthma, low educational and socioeconomic levels, and lack of medical care and of inhaled steroid use.

Characterization of autopsy-proven fatal asthma patients in São Paulo, Brazil / Caracterización de los pacientes fallecidos por asma certificada por autopsia en São Paulo, Brasil

Few data are available on autopsy-proven fatal asthma patients in São Paulo, Brazil. We characterized 73 asthma patients who were autopsied at the Serviço de Verificação de Óbitos da Universidade de São Paulo between 1996 and 2004. An interview with the next of kin assessed socioeconomic status, history, and treatment of asthma. There were 42 women and 31 men. Fifty-six (76.7 percent) of them were older than 34 years. Sixty-three percent were Caucasians, 77.3 percent had < 8 years of schooling, and the median income was 1.6 times the minimum wage. Twenty-two patients (30.1 percent) were smokers and 14 (19.2 percent) were ex-smokers. Only 25 (34.2 percent) patients were regularly followed by a doctor. Only 12.3 percent received inhaled steroids. Thirty-five patients (47.9 percent) had moderate-to-severe asthma. Fifty-five (75.3 percent) deaths took place outside a hospital. We conclude that this population shares characteristics of severe or poorly controlled asthma, low educational and socioeconomic levels, and lack of medical care and of inhaled steroid use.

Se cuenta con poca información acerca de los pacientes fallecidos por asma certificada por autopsia en São Paulo, Brasil. Se caracterizaron 73 pacientes de asma sometidos a autopsia en el Serviço de Verificação de Óbitos da Universidade de São Paulo entre 1996 y 2004. Mediante entrevistas con sus parientes se estableció el nivel socioeconómico, los antecedentes de asma y el tratamiento seguido. Del los 73 pacientes (42 mujeres y 31 hombres), 56 (76,7 por ciento) eran mayores de 34 años; 63,0 por ciento eran caucásicos y 77,3 por ciento tenían menos de 8 años de escolaridad. La mediana de los ingresos era de 1,6 veces el salario mínimo. De los pacientes, 22 (30,1 por ciento) eran fumadores y 14 (19,2 por ciento) lo habían sido. Solamente 25 (34,2 por ciento) pacientes tenían seguimiento médico regular y solo 12,3 por ciento usaba inhaladores de esteroides; 35 (47,9 por ciento) presentaban asma moderada o intensa; 55 (75,3 por ciento) de las muertes ocurrieron fuera de los hospitales. Se concluye que esta población se caracterizaba por padecer de asma intensa o poco controlada, bajo nivel educacional y socioeconómico, carecía de atención médica y no usaba inhaladores de esteroides.

Collagen fiber and versican distribution within the lamina propria of fetal vocal folds.

OBJECTIVES: To analyze the presence and distribution of collagen fibers and versican in human vocal fold lamina propria of fetal larynges. STUDY DESIGN: Cross sectional analysis of cadaveric vocal folds of human fetuses. METHODS: Seven fetal larynges obtained from 28- to 36-week-old fetuses were analyzed with the Picrosirius-polarization method, immunohistochemistry, and image analysis. RESULTS: Collagen fibers within the lamina propria exhibited a monolaminar distribution pattern and spatial arrangement in "wicker basket." Versican distribution was larger in the superficial and intermediate layers when compared to the deep layer. CONCLUSION: Our findings suggest that collagen and versican distribution and arrangement within the lamina propria in the developing fetus are important for vocalization at birth.

Cirrose hepática: aspectos morfológicos relacionados às suas possíveis complicações. Um estudo centrado em necropsias / Hepatic cirrhosis: morphologic aspects related to its possible complications. A study focused on necropsies

INTRODUÇAO: A cirrose hepática é muito prevalente em nosso meio, cursando freqüentemente com complicações como insuficiência e carcinoma hepatocelulares e hipertensão portal. OBJETIVOS: Analisar os aspectos clínicos e morfológicos das cirroses, relacionando-os com os principais padrões histológicos e suas complicações. MATERIAL E MÉTODO: Entre 35 fígados cirróticos provenientes de necropsias realizadas no Serviço de Verificação de Obitos da Capital (SVOC-SP), estudados em cortes seqüenciais a cada centímetro, dois padrões anatomopatológicos predominaram: os associados a hepatites crônicas e os decorrentes de esteato-hepatites. RESULTADOS E DISCUSSAO: A alta incidência de cirrose em necropsias (7,1 por cento), com freqüente detecção de macronódulos (62,8 por cento) e de carcinoma hepatocelular (CHC) (37,1 por cento), aponta para a relevância dessas questões em saúde pública. A análise histológica demonstrou o encontro de neoductos, agressão biliar e siderose com maior freqüência na hepatite crônica que na esteato-hepatite. CONCLUSÕES: Essa abordagem sistemática nos espécimes necroscópicos permitiu-nos a identificação de elevada freqüência de cirrose em necropsias do SVOC e, em especial, daquelas decorrentes de hepatites crônicas, aspecto de interesse sanitário. A freqüente detecção de CHC, além de constituir modelo para futuros estudos sobre o surgimento dessas neoplasias, demonstra ser uma das principais complicações da cirrose avançada, qualquer que seja sua causa.

Lung parenchyma remodeling in a murine model of chronic allergic inflammation.

This study tested the hypotheses that chronic allergic inflammation induces not only bronchial but also lung parenchyma remodeling, and that these histologic changes are associated with concurrent changes in respiratory mechanics. For this purpose, airway and lung parenchyma remodeling were evaluated by quantitative analysis of collagen and elastin, immunohistochemistry (smooth-muscle actin expression, eosinophil, and dendritic cell densities), and electron microscopy. In vivo (airway resistance, viscoelastic pressure, and static elastance) and in vitro (tissue elastance, resistance, and hysteresivity) respiratory mechanics were also analyzed. BALB/c mice were sensitized with ovalbumin and exposed to repeated ovalbumin challenges. A marked eosinophilic infiltration was seen in lung parenchyma and in large and distal airways. Neutrophils, lymphocytes, and dendritic cells also infiltrated the lungs. There was subepithelial fibrosis, myocyte hypertrophy and hyperplasia, elastic fiber fragmentation, and increased numbers of myofibroblasts in airways and lung parenchyma. Collagen fiber content was increased in the alveolar walls. The volume proportion of smooth muscle-specific actin was augmented in distal airways and alveolar duct walls. Airway resistance, viscoelastic pressure, static elastance, and tissue elastance and resistance were significantly increased. In conclusion, prolonged allergen exposure induced remodeling not only of the airway wall but also of the lung parenchyma, leading to in vivo and in vitro mechanical changes.