Testicular pathology in fatal COVID-19: A descriptive autopsy study.

BACKGROUND: Multi-organ damage is a common feature of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, going beyond the initially observed severe pneumonia. Evidence that the testis is also compromised is growing. OBJECTIVE: To describe the pathological findings in testes from fatal cases of COVID-19, including the detection of viral particles and antigens, and inflammatory cell subsets. MATERIALS AND METHODS: Postmortem testicular samples were obtained by percutaneous puncture from 11 deceased men and examined by reverse-transcription polymerase chain reaction (RT-PCR) for RNA detection and by light and electron microscopy (EM) for SARS-CoV-2. Immunohistochemistry (IHC) for the SARS-CoV-2 N-protein and lymphocytic and histiocytic markers was also performed. RESULTS: Eight patients had mild interstitial orchitis, composed mainly of CD68+ and TCD8+ cells. Fibrin thrombi were detected in five cases. All cases presented congestion, interstitial edema, thickening of the tubular basal membrane, decreased Leydig and Sertoli cells with reduced spermatogenesis, and strong expression of vascular cell adhesion molecule (VCAM) in vessels. IHC detected SARS-Cov-2 antigen in Leydig cells, Sertoli cells, spermatogonia, and fibroblasts in all cases. EM detected viral particles in the cytoplasm of fibroblasts, endothelium, Sertoli and Leydig cells, spermatids, and epithelial cells of the rete testis in four cases, while RT-PCR detected SARS-CoV-2 RNA in three cases. DISCUSSION AND CONCLUSION: The COVID-19-associated testicular lesion revealed a combination of orchitis, vascular changes, basal membrane thickening, Leydig and Sertoli cell scarcity, and reduced spermatogenesis associated with SARS-CoV-2 local infection that may impair hormonal function and fertility in men.

Pulmonary and systemic involvement in COVID-19 patients assessed with ultrasound-guided minimally invasive autopsy.

AIMS: Brazil ranks high in the number of coronavirus disease 19 (COVID-19) cases and the COVID-19 mortality rate. In this context, autopsies are important to confirm the disease, determine associated conditions, and study the pathophysiology of this novel disease. The aim of this study was to assess the systemic involvement of COVID-19. In order to follow biosafety recommendations, we used ultrasound-guided minimally invasive autopsy (MIA-US), and we present the results of 10 initial autopsies. METHODS AND RESULTS: We used MIA-US for tissue sampling of the lungs, liver, heart, kidneys, spleen, brain, skin, skeletal muscle and testis for histology, and reverse transcription polymerase chain reaction to detect severe acute respiratory syndrome coronavirus 2 RNA. All patients showed exudative/proliferative diffuse alveolar damage. There were intense pleomorphic cytopathic effects on the respiratory epithelium, including airway and alveolar cells. Fibrinous thrombi in alveolar arterioles were present in eight patients, and all patients showed a high density of alveolar megakaryocytes. Small thrombi were less frequently observed in the glomeruli, spleen, heart, dermis, testis, and liver sinusoids. The main systemic findings were associated with comorbidities, age, and sepsis, in addition to possible tissue damage due to the viral infection, such as myositis, dermatitis, myocarditis, and orchitis. CONCLUSIONS: MIA-US is safe and effective for the study of severe COVID-19. Our findings show that COVID-19 is a systemic disease causing major events in the lungs and with involvement of various organs and tissues. Pulmonary changes result from severe epithelial injury and microthrombotic vascular phenomena. These findings indicate that both epithelial and vascular injury should be addressed in therapeutic approaches.

Chronic exposure of diesel exhaust particles induces alveolar enlargement in mice.

BACKGROUND: Diesel exhaust particles (DEPs) are deposited into the respiratory tract and are thought to be a risk factor for the development of diseases of the respiratory system. In healthy individuals, the timing and mechanisms of respiratory tract injuries caused by chronic exposure to air pollution remain to be clarified. METHODS: We evaluated the effects of chronic exposure to DEP at doses below those found in a typical bus corridor in Sao Paulo (150 µg/m3). Male BALB/c mice were divided into mice receiving a nasal instillation: saline (saline; n = 30) and 30 µg/10 µL of DEP (DEP; n = 30). Nasal instillations were performed five days a week, over a period of 90 days. Bronchoalveolar lavage (BAL) was performed, and the concentrations of interleukin (IL)-4, IL-10, IL-13 and interferon-gamma (INF-γ) were determined by ELISA-immunoassay. Assessment of respiratory mechanics was performed. The gene expression of Muc5ac in lung was evaluated by RT-PCR. The presence of IL-13, MAC2+ macrophages, CD3+, CD4+, CD8+ T cells and CD20+ B cells in tissues was analysed by immunohistochemistry. Bronchial thickness and the collagen/elastic fibers density were evaluated by morphometry. We measured the mean linear intercept (Lm), a measure of alveolar distension, and the mean airspace diameter (D0) and statistical distribution (D2). RESULTS: DEP decreased IFN-γ levels in BAL (p = 0.03), but did not significantly alter IL-4, IL-10 and IL-13 levels. MAC2+ macrophage, CD4+ T cell and CD20+ B cell numbers were not altered; however, numbers of CD3+ T cells (p ≤ 0.001) and CD8+ T cells (p ≤ 0.001) increased in the parenchyma. Although IL-13 (p = 0.008) expression decreased in the bronchiolar epithelium, Muc5ac gene expression was not altered in the lung of DEP-exposed animals. Although respiratory mechanics, elastic and collagen density were not modified, the mean linear intercept (Lm) was increased in the DEP-exposed animals (p ≤ 0.001), and the index D2 was statistically different (p = 0.038) from the control animals. CONCLUSION: Our data suggest that nasal instillation of low doses of DEP over a period of 90 days results in alveolar enlargement in the pulmonary parenchyma of healthy mice.

Respiratory toxicity of repeated exposure to particles produced by traffic and sugar cane burning.

We compared the toxicity of subchronic exposure to equivalent masses of particles from sugar cane burning and traffic. BALB/c mice received 3 intranasal instillations/week during 1, 2 or 4 weeks of either distilled water (C1, C2, C4) or particles (15µg) from traffic (UP1, UP2, UP4) or biomass burning (BP1, BP2, BP4). Lung mechanics, histology and oxidative stress were analyzed 24h after the last instillation. In all instances UP and BP groups presented worse pulmonary elastance, airway and tissue resistance, alveolar collapse, bronchoconstriction and macrophage influx into the lungs than controls. UP4, BP2 and BP4 presented more alveolar collapse than UP1 and BP1, respectively. UP and BP had worse bronchial and alveolar lesion scores than their controls; BP4 had greater bronchial lesion scores than UP4. Catalase was higher in UP4 and BP4 than in C4. In conclusion, biomass particles were more toxic than those from traffic after repeated exposures.

Airway dimensions in fatal asthma and fatal COPD: overlap in older patients.

In some patients with chronic asthma clinical and physiological similarities with COPD may exist, such as partial reversibility to bronchodilators and persistent expiratory airflow obstruction. However, pathological data comparing both diseases in patients of similar age and disease severity are scarce. We compared large and small airway dimensions in 12 younger (mean age 32 yrs) and 15 older (mean age 65 yrs) non-smoker adult fatal asthma patients with 14 chronic smokers with severe, fatal COPD (mean age 71 yrs). Using H&E, Movat pentachrome staining and image analysis, we quantified large airway basement membrane (BM) thickness (µm), submucosal gland area and large and small airway inner wall, smooth muscle and outer wall areas. Areas were normalized by BM perimeter (µm(2)/µm). Younger adult fatal asthma patients had thicker BM, smooth muscle, and outer wall areas in both small and large airways when compared to COPD patients. In older asthmatics there was an overlap in BM thickness and airway structure in small airways. Inner wall layer in large and small airway level and submucosal gland areas were similar among groups. In conclusion, there are airway histological structural similarities between fatal asthma and fatal COPD. Older fatal asthmatics present overlapping airway structural features with younger adult fatal asthmatics and severe COPD patients. Our data contributes to a better understanding of asthma pathology in the elderly.

The extracellular matrix of the lateral pharyngeal wall in obstructive sleep apnea.

STUDY OBJECTIVES: To compare the components of the extracellular matrix in the lateral pharyngeal muscular wall in patients with and without obstructive sleep apnea (OSA). This may help to explain the origin of the increased collapsibility of the pharynx in patients with OSA. DESIGN: Specimens from the superior pharyngeal constrictor muscle, obtained during pharyngeal surgeries, were evaluated using histochemical and immunohistochemical analyses to determine the fractional area of collagen types I and III, elastic fibers, versican, fibronectin, and matrix metalloproteinases 1 and 2 in the endomysium. SETTING: Academic tertiary center. PATIENS: A total of 51 nonobese adult patients, divided into 38 patients with OSA and 13 nonsnoring control subjects without OSA. INTERVENTIONS: Postintervention study performed on tissues from patients after elective surgery. MEASUREMENTS AND RESULTS: Pharyngeal muscles of patients with OSA had significantly more collagen type I than pharyngeal muscles in control subjects. Collagen type I was correlated positively and independently with age. The other tested components of the extracellular matrix did not differ significantly between groups. In a logistic regression, an additive effect of both the increase of collagen type I and the increase in age with the presence of OSA was observed (odds ratio (OR), 2.06; 95% confidence interval (CI), 1.17-3.63), when compared with the effect of increased age alone (OR, 1.11; 95% CI, 1.03-1.20). CONCLUSION: Collagen type I in the superior pharyngeal constrictor muscle was more prevalent in patients with OSA and also increased with age. It was hypothesized that this increase could delay contractile-relaxant responses in the superior pharyngeal constrictor muscle at the expiratory-inspiratory phase transition, thus increasing pharyngeal collapsibility.

Depletion of Langerhans cells in the tongue from patients with advanced-stage acquired immune deficiency syndrome: relation to opportunistic infections.

AIMS: To quantify and compare the expression of Langerhans cells (LCs) in the tongue mucosa of AIDS patients with different opportunistic infections, and from acquired immune deficiency syndrome (AIDS) and non-AIDS patients with normal tongues, using autopsy material. METHODS AND RESULTS: Human leucocyte antigen D-related (HLA-DR), CD1a and CD83 antibodies were used to identify and quantify LCs by immunohistochemistry in tongue tissue of 40 AIDS patients (10 with lingual candidiasis, 10 with lingual herpes, 10 with oral hairy leukoplakia and 10 with no lesions) and 23 tongues from human immunodeficiency virus (HIV)-negative control patients. Quantification was performed by means of conventional morphometry in four different regions (anterior, middle, posterior and lateral) of the tongue. The results were expressed as positive cells per area of epithelium. The AIDS patients presented a lower density of CD1a(+) cells (P < 0.001), HLA-DR (P < 0.003) and CD83 (P < 0.001) in all regions of the tongue compared to the non-AIDS control group. However, no differences in any of the markers were found when AIDS patients with different opportunistic infections were compared with AIDS patients without tongue infection. CONCLUSIONS: Advanced stage AIDS patients showed a depletion of LCs in the tongue mucosa. HIV infection induces cytopathic changes in LCs, contributing to their depletion regardless of the presence of oral infections.

Small airway remodeling in acute respiratory distress syndrome: a study in autopsy lung tissue.

INTRODUCTION: Airway dysfunction in patients with the Acute Respiratory Distress Syndrome (ARDS) is evidenced by expiratory flow limitation and dynamic hyperinflation. These functional alterations have been attributed to closure/obstruction of small airways. Airway morphological changes have been reported in experimental models of acute lung injury, characterized by epithelial necrosis and denudation in distal airways. To date, however, no study has focused on the morphological airway changes in lungs from human subjects with ARDS. The aim of this study is to evaluate structural and inflammatory changes in distal airways in ARDS patients. METHODS: We retrospectively studied autopsy lung tissue from subjects who died with ARDS and from control subjects who died of non pulmonary causes. Using image analysis, we quantified the extension of epithelial changes (normal, abnormal and denudated epithelium expressed as percentages of the total epithelium length), bronchiolar inflammation, airway wall thickness, and extracellular matrix (ECM) protein content in distal airways. The Student's t-test or the Mann-Whitney test was used to compare data between the ARDS and control groups. Bonferroni adjustments were used for multiple tests. The association between morphological and clinical data was analyzed by Pearson rank test. RESULTS: Thirty-one ARDS patients (A: PaO2/FiO2 ≤200, 45 ± 14 years, 16 males) and 11 controls (C: 52 ± 16 years, 7 males) were included in the study. ARDS airways showed a shorter extension of normal epithelium (A:32.9 ± 27.2%, C:76.7 ± 32.7%, P < 0.001), a larger extension of epithelium denudation (A:52.6 ± 35.2%, C:21.8 ± 32.1%, P < 0.01), increased airway inflammation (A:1(3), C:0(1), P = 0.03), higher airway wall thickness (A:138.7 ± 54.3 µm, C:86.4 ± 33.3 µm, P < 0.01), and higher airway content of collagen I, fibronectin, versican and matrix metalloproteinase-9 (MMP-9) compared to controls (P ≤0.03). The extension of normal epithelium showed a positive correlation with PaO2/FiO2 (r2 = 0.34; P = 0.02) and a negative correlation with plateau pressure (r2 = 0.27; P = 0.04). The extension of denuded epithelium showed a negative correlation with PaO2/FiO2 (r2 = 0.27; P = 0.04). CONCLUSIONS: Structural changes in small airways of patients with ARDS were characterized by epithelial denudation, inflammation and airway wall thickening with ECM remodeling. These changes are likely to contribute to functional airway changes in patients with ARDS.

Lung pathology in fatal novel human influenza A (H1N1) infection.

RATIONALE: There are no reports of the systemic human pathology of the novel swine H1N1 influenza (S-OIV) infection. OBJECTIVES: The autopsy findings of 21 Brazilian patients with confirmed S-OIV infection are presented. These patients died in the winter of the southern hemisphere 2009 pandemic, with acute respiratory failure. METHODS: Lung tissue was submitted to virologic and bacteriologic analysis with real-time reverse transcriptase polymerase chain reaction and electron microscopy. Expression of toll-like receptor (TLR)-3, IFN-gamma, tumor necrosis factor-alpha, CD8(+) T cells and granzyme B(+) cells in the lungs was investigated by immunohistochemistry. MEASUREMENTS AND MAIN RESULTS: Patients were aged from 1 to 68 years (72% between 30 and 59 yr) and 12 were male. Sixteen patients had preexisting medical conditions. Diffuse alveolar damage was present in 20 individuals. In six patients, diffuse alveolar damage was associated with necrotizing bronchiolitis and in five with extensive hemorrhage. There was also a cytopathic effect in the bronchial and alveolar epithelial cells, as well as necrosis, epithelial hyperplasia, and squamous metaplasia of the large airways. There was marked expression of TLR-3 and IFN-gamma and a large number of CD8(+) T cells and granzyme B(+) cells within the lung tissue. Changes in other organs were mainly secondary to multiple organ failure. CONCLUSIONS: Autopsies have shown that the main pathological changes associated with S-OIV infection are localized to the lungs, where three distinct histological patterns can be identified. We also show evidence of ongoing pulmonary aberrant immune response. Our results reinforce the usefulness of autopsy in increasing the understanding of the novel human influenza A (H1N1) infection.

The outer wall of small airways is a major site of remodeling in fatal asthma.

BACKGROUND: Structural and inflammatory changes in asthma involve both the large and small airways, with involvement of the distal lung being related to disease severity. We have previously shown that changes in the extracellular matrix (ECM) composition of the distal lung are associated with loss of alveolar attachments in patients with fatal asthma. However, major ECM elements, such as collagen I and fibronectin and their regulators, have not been addressed at the distal level. OBJECTIVE: We sought to evaluate ECM remodeling in the distal lungs of asthmatic patients. METHODS: Using immunohistochemistry and image analysis, we determined the content of collagen I and III, fibronectin, and matrix metalloproteinases (MMPs) 1, 2, and 9 and tissue inhibitors of metalloproteinase (TIMPs) 1 and 2 in the large and small airways and lung parenchyma of 24 patients with fatal asthma and compared the results with those of 11 nonasthmatic control subjects. Protein content was defined as the area of positive staining divided by basement membrane or septum length. RESULTS: We observed increased collagen I and decreased collagen III content in the small airways of asthmatic patients compared with that seen in control subjects. Greater fibronectin and MMP-1, MMP-2, and MMP-9 content was observed at the outer area of the small airways in asthmatic patients. MMP content was also increased in the peribronchiolar parenchyma in asthmatic patients. In contrast, TIMP expression was only increased in the large airways of asthmatic patients compared with that seen in control subjects. CONCLUSIONS: The outer area of the small airways is a major site of ECM remodeling in fatal asthma, potentially contributing to functional changes and the loss of airway-parenchyma interdependence observed in patients with fatal asthma.