Co-exposure to urban particulate matter and aircraft noise adversely impacts the cerebro-pulmonary-cardiovascular axis in mice

Worldwide, up to 8.8 million excess deaths/year have been attributed to air pollution, mainly due to the exposure to fine particulate matter (PM). Traffic-related noise is an additional contributor to global mortality and morbidity. Both health risk factors substantially contribute to cardiovascular, metabolic and neuropsychiatric sequelae. Studies on the combined exposure are rare and urgently needed because of frequent co-occurrence of both risk factors in urban and industrial settings. To study the synergistic effects of PM and noise, we used an exposure system equipped with aerosol generator and loud-speakers, where C57BL/6 mice were acutely exposed for 3d to either ambient PM (NIST particles) and/or noise (aircraft landing and take-off events). The combination of both stressors caused endothelial dysfunction, increased blood pressure, oxidative stress and inflammation. An additive impairment of endothelial function was observed in isolated aortic rings and even more pronounced in cerebral and retinal arterioles. The increase in oxidative stress and inflammation markers together with RNA sequencing data indicate that noise particularly affects the brain and PM particularly affects the lungs. Noise also increased levels of circulating stress hormones adrenaline and noradrenaline, while PM increased levels of circulating cytokines CD68 and MCP-1. The combination of both stressors has additive adverse effects on the cardiovascular system that are based on PM-induced systemic inflammation and noise-triggered stress hormone signaling. We demonstrate an additive upregulation of ACE-2 in the lung, suggesting that there may be an increased vulnerability to COVID-19 infection. The data warrant further mechanistic studies to characterize the propagation of primary target tissue damage (lung, brain) to remote organs such as aorta and heart by combined noise and PM exposure.Copyright © 2023

Evaluation of lung cell populations in severe COVID-19 pneumonia

Introduction/Aim: Coronavirus disease 2019 (COVID-19) is a novel viral infection that can cause severe pneumonia and acute respiratory failure;however, the mechanism of disease progression is still unclear. The aim of this study is to evaluate inflammatory cells in the lung by analysing cell populations of bronchial aspirates of COVID-19 pneumonia. Method(s): Eligible cases were diagnosed as COVID-19, confirmed by SARS-CoV-2 PCR. All cases had developed severe COVID-19 pneumonia and undergone invasive positive pressure ventilation for the treatment of respiratory failure. Bronchial aspirates were collected during endotracheal intubation, and SARS-CoV-2 PCR was done. The populations of obtained cells from bronchial aspirates were examined by Giemsa staining and immunohistochemical staining of CD3, CD4, CD8, CD20 and CD68 antigens. Bronchial aspirates were cultured to confirm respiratory bacterial co-infections. Result(s): A total of 14 cases (median age 70;eleven male and three female) were enrolled in this study. Their bronchial aspirates were all positive for SARS-CoV-2 PCR. Bacterial co-infections were developed in 10 cases, including 6 cases of pneumonia/respiratory tract infection, 2 cases of sepsis, and 2 cases of urinary tract infection. Cell populations of bronchial aspirates with or without bacterial co-infections were as follows: neutrophils 33.0% vs. 21.5%;CD3+ mononuclear cells (MNCs) 2.5% vs. 5.8%;CD4+ MNCs 4.6% vs. 3.4%;CD8+ MNCs 3.5% vs. 5.2%;CD20+ MNCs 0.2% vs. 0.1%;CD68+ MNCs 39.7% vs. 38.8%, respectively. Conclusion(s): CD68 antigen is mainly expressed in monocytes/macrophages. CD68+ MNCs were dominant in bronchial aspirates of the cases with severe COVID-19 pneumonia. Our data suggests that CD68+ MNCs, presumably macrophages, would play an essential role during the innate immune response to acute SARS-CoV-2 infection in the lung.

Unusual Myositis of the Temporalis Muscle Occurring with Acute Covid-19

Background. SARS-CoV-2 infection can be accompanied by neuromuscular disorders. Rhabdomyolysis and Guillain-Barre syndrome have been described repeatedly. There are case reports of inflammatory myopathies manifesting during COVID-19, presenting as dermatomyositis, polymyositis or immune-mediated necrotizing myopathy, with dermatomyositis-like presentations most commonly reported. Larger cases series are from postmortem examinations of COVID-19 patients, where variable inflammatory pathology of the skeletal muscle has been found frequently but without local detection of the actual virus. Thus, autoimmune mechanisms or the systemic interferon response are discussed as causes. We report a case of focal inflammatory myopathy with perimysial pathology of the temporalis muscle occurring with acute, but mild COVID-19. Methods. Case report of clinical observations, cranial MRI, histopathological, and laboratory findings. 3T cranial MRI was performed with gadolinium contrast. Open temporalis muscle biopsy was performed. The sample underwent standard cryohistological studies as well as immunohistochemistry with antibodies against MHC-I and II, CD3, CD4, CD19, CD68, anti-MAC, p62 and MxA. Testing for auto-antibodies was based on immunoblots or ELISA. RT-PCR for SARS-CoV-2 was run with RNA extracted from cryopreserved muscle. Results. A Caucasian woman in her 60s with no history of autoimmune or muscle complaints developed swelling and pain of the right jaw musculature five days after testing positive for SARS-CoV-2 due to respiratory tract symptoms. In addition, she experienced trismus, but no further neuromuscular complaints. The course of respiratory tract symptoms stayed mild. She had been vaccinated previously with single shot SARS-CoV-2 vector vaccine. Due to persistent swelling and complaints, giant cells arteritis was excluded by unresponsiveness to five days oral steroids and sonography of the temporal artery. Cranial MRI was performed nearly four weeks after the SARS-CoV-2 infection and showed marked swelling and oedema of the temporalis muscle. Its biopsy showed numerous CD68 and acid phosphatase positive cells infiltrating from perimysial perivascular foci towards the endomysium with perimysial damage but little damage of adjacent, perifascicular muscle fibres. Muscle fibres did not react with anti-MHC-II, anti-MAC or -MxA. Capillaries did not react with anti-MAC or -MxA. SARS-CoV-2 RNA was not detected in muscle tissue. Serum creatine kinase was not elevated in the subacute phase. Slightly elevated ANA titre led to detection of autoantibodies against proliferating cell nuclear antigen (PCNA). No pathological results for other autoantibodies, including myositis-specific antibodies and anti-ds-DNA, were found in blood. Neither were antibodies against hepatitis C and B viruses. Retesting 15 weeks after infection, anti-PCNA immunoblot was still positive, but ELISA did not indicate a pathologic titre. The swelling, myalgia and trismus regressed spontaneously a month after onset, yet the latter still persists at the time of reporting. Conclusion. Our case diverges from the majority of COVID-19 associated my-ositis reports in the unusual location of the focal myositis and the histopathological pattern of predominantly perimysial damage and histiocytic infiltration. It concurs with the literature as no SARS-CoV2 RNA could be detected in the muscle. Anti-PCNA is associated very rarely with myositis. Other associated disorder (systemic lupus erythematosus, chronic viral hepatitis B or C) were not found. Increased levels of autoantibodies are reported in COVID-19 and mostly attributed to loss of self-tolerance during the acute disease phase. Interestingly, the structural protein M of SARS-CoV-2 appears to interact notably with PCNA in infected cells. Still, the causal connection between the myositis and COVID-19 in this case is based on the close temporal association in the absence of alternative, competing explanations from the medical history and findings.

Histopathologic changes in lung tissue after Covid-19 pneumonia

Current knowledge of histopathological changes in Covid-19 pneumonia is mainly based on autopsy findings. There are few data on dynamics of lung lesions in vivo after acute phase of disease. The aim of this study was to determine histopathologic changes during the long/post-Covid stage in patients who had suffered from moderate to severe Covid-19 pneumonia. Bronchoscopy with transbronchial lung biopsy was performed in patients with HRCT lesions involving >40% of lung parenchyma, at least 4 weeks after discharge. Additional criteria were restrictive pattern in lung function tests and signed informed consent. Histopathologic analyses were performed using H&E, MSB, MOVAT, TTF1, CD34 and CD68 staining. Research was approved by the Hospital Ethical Committee. Among 26 patients that met inclusion criteria, adequate biopsy samples were obtained from 24. The mean time from the onset of disease to biopsy was 13 weeks. We found 4 histopathologic patterns: diffuse alveolar damage-DAD with vascular abnormalities, nonspecific interstitial inflammation, organizing pneumonia and interstitial fibrosis in 11, 9, 2 and 2 patients, respectively. Vascular abnormalities included capillary thrombi, dilated venules and dissection of small pulmonary arteries. Given the duration of disease, DAD and vascular abnormalities were detected up to the 12 week from the onset of symptoms. All patients biopsied after 12th weeks had some degree of tissue inflammation without vascular changes. Our findings show rather slow recovery of lung tissue after Covid-19 pneumonia. Long lasting DAD with vascular abnormalities may explain prolonged dyspnea and exercise intolerance and should be taken into consideration when planning further rehabilitation.

Clinical, morphological and molecular biological examination of the myocardium in COVID-19 patients

The presence of coronavirus-associated myocarditis remains controversial despite elevations in cardiac troponin and natriuretic peptide in many patients. Aim. To assess the morphological changes in the myocardium of patients who died due to coronavirus disease 2019 (COVID-19) and compare them with the intravital level of cardiac biomarkers. Material and methods. A total of 420 hospital charts and 77 autopsies of those who died from COVID-19 were analyzed. In 15 of 77 cases (19%) with histologically suspected myocarditis, an immunohistochemical examination of the myocardium with antibodies to CD3, CD45, CD8, CD68, CD34, Ang1, VWF, VEGF, HLA-DR, MHC1, C1q, VP1 of enteroviruses was performed, and in 8 patients with immunohistochemically confirmed myocarditis (10%) — polymerase chain reaction for SARS-CoV-2. Results. Hemorrhage, intramural thrombosis, necrosis of non-coronary origin, myocardial infarction and lymphocytic myocarditis were detected in 43%, 10%, 17%, 19% and 10% of cases, respectively, without coronavirus N and E gene sequences in the myocardium. Dysplasia, hyperplasia and hypertrophy of the vascular endothelium, expression of Ang1, VWF, VEGF, MHC1, C1q, VP1 of enteroviruses were determined in 100, 100, 87, 100, 75 and 62% of cases of myocarditis, respectively. There were no significant correlations between inflammatory biomarkers and myo-carditis. Conclusion. The main morphological manifestation of COVID-19 in the myo-cardium is the so-called endotheliitis with dysplasia and endothelial activation, leading to hemorrhages, intramural thrombosis and necrosis. There is no con-vincing evidence of a direct involvement of coronavirus in myocarditis induction.

MISDIAGNOSIS OF KIKUCHI-FUJIMOTO DISEASE: THE IMPORTANCE OF TIMELY HISTOPATHOLOGY IN LYMPHADENITIS

Background: Febrile lymphadenopathy not responding to first line antibiotics in a patient hailing from or with a history of travel to tuberculosis endemic countries is often primarily diagnosed as extra-pulmonary tuberculosis. However, histiocytic necrotizing lymphadenitis or Kikuchi-Fujimoto Disease(KFD) presents with similar clinical features. Etiological theories of KFD include viral agents, autoimmunity, and physicochemical factors such as leaking implants. Although KFD has classically been described in young Asian females, recent studies show men and women can be equally affected, with cases increasingly being reported from the USA and Europe as well. Availability bias amongst physicians can lead to misdiagnoses, especially in patients from tuberculosis endemic countries. Objectives: To describe a case of misdiagnosis of KFD in an adolescent. Design/Method: Case report. Results: A 16-year-old male from a tuberculosis endemic country, with a history of asthma, eczema and excision of omental infarct, presented with sub-occipital lymphadenopathy which resolved with antibiotics. Six months later, he complained of tender left cervical lymphadenopathy, associated with fever and fatigue, which lasted for a month. Two courses of antibiotics failed to decrease symptoms. Based on his clinical history, he was started on empirical anti-tubercular medications despite negative tests for tuberculosis. However, his symptoms began to worsen after three weeks of this treatment, and he developed high evening rise of temperature associated with chills, night sweats, frontal headache, pedal edema and generalized pruritic maculopapular rash. Laboratory workups revealed leukopenia (WBC:3830/μL);elevated Erythrocyte sedimentation rate (29 mm/h), C-reactive protein (68.6 mg/dL), Aspartate Aminotransferase(95 U/L) and Alanine Aminotransferase(61 U/L). Rapid antigen test for SARS-CoV2 was negative, and no appreciable levels of SARS-CoV-2 IgG antibodies were detected. Investigations for Tuberculosis, EBV, CMV, Dengue, Malaria, Typhoid, Leptospirosis and Scrub typhus were all negative. Chest X-ray and abdomen ultrasound scan were normal. Histopathological analysis of the excised cervical lymph nodes demonstrated crescentic histiocytes and karyorrhexis in a background of coagulative necrosis. Neutrophils, granulomas and acid-fast bacilli were absent. Immunohistochemistry was positive for CD3, CD20, CD68;and negative for CD15, CD30 and PAX-5. A diagnosis of KFD was made, and patient was given supportive treatment only. His symptoms rapidly resolved within 48 hours, with complete resolution by three months. Conclusion: It is important to raise awareness of KFD, a benign and self-limiting condition with good prognosis, which has many clinical symptoms mimicking grave conditions like extra-pulmonary tuberculosis, SLE and lymphomas. Timely histopathological analysis can help avoid anxiety surrounding a misdiagnosis and adverse reactions due to unnecessary toxic treatments.

LOSS of TOLERANCE and ANERGY in HUMAN PERIPHERAL B CELLS during SARS-CoV-2 INFECTION

Background: Severe infection with SARS-CoV-2 induces systemic autoreactive antibodies with specificity to Type I IFN, phospholipids, nuclear or tissue specific targets. The wide breadth of targets suggests a system-wide defect in B cell tolerance during viral infection and that the source of autoreactive antibodies is likely a heterogenous subset of B cells. BND cells are mature naïve B cells that do not express IgM but do express IgD and are enriched in autoreactive specificities. BND cells are held in an anergic state in healthy humans as a mechanism of peripheral tolerance, although in vitro evidence suggests anergy can be broken with strong inflammation. We hypothesized that robust inflammation associated with viral infection from SARS-CoV2 may relax peripheral tolerance and promote breakage of BND cell anergy. Methods: Plasma and PBMCs were collected from healthy controls (N=10), subjects immunized with Pfizer BNT162b2-mRNA/Moderna mRNA-1273 (N=10), subjects with mild (N=11) or severe SARS-CoV-2 infection (N=14). BND cells were examined ex vivo for markers of activation by flow cytometry. Phosphorylation of signaling proteins downstream of the BCR were measured in vitro with or without BCR crosslinking. Inflammatory cytokines were measured in plasma by multiplex. For statistical analysis, unpaired t test between populations or paired t test between unstimulated and BCR stimulated conditions were performed. Results: BND cells from severe SARS-CoV-2 infection have lower expression of CD21, associated with loss of anergy, higher expression of activation markers CD68 and CD86 with lower expression of inhibitory receptors CD22 and CD72 when compared to BND cells from other subjects, suggesting a phenotypical breach of anergy. Upon BCR crosslinking, BND cells have higher levels of downstream signaling components of the BCR (pPLCγ2, pBlnk, and pSyk) when compared to healthy controls and immunized subjects, suggesting a functional breach in anergy with infection. Examination of plasma from severe SARS-CoV-2 infection showed higher levels of inflammatory cytokines (IFNγ, TNFα, IL-6 and CRP) where TNFα and CRP correlated with enhanced BCR signaling in BND cells. Conclusion: We demonstrate that SARS-CoV-2 viral infection relaxes peripheral tolerance of BND cells, likely through strong systemic inflammation produced during infection. These autoreactive cells overcome anergy and become activated with increased BCR signaling. Thus BND cells could be a source of autoreactive antibodies during viral infection.

COVID-19 microglia encephalopathy: Immunohistological assessment

Aims: Activation of microglial cells represents the most common neu-ropathological change in fatal cases of COVID-19 with particular prominence in the brainstem. However, detailed assessments are lacking. Here, we assessed reactive microglia in COVID-19 tissue and tested for disease-specific activation patterns. Methods: We used an early-(Iba1) and a late-stage (CD68) immuno-histochemistry marker for microglial activation in human post-mortem brainstem and frontal lobe tissues in eight fatal COVID-19 cases, seven septic controls and six non-septic controls. We quantified the level of microglial activation employing a Qu-Path-based automated approach. Using a mixed three-way ANOVA, we tested for effects and interactions of brain region, microglial marker and group. Results: Reactive microglia were detected in all cases across brain regions and antibodies. However, COVID-19 brains exhibited significantly higher levels of microglial activation than septic and control brains, especially of late-stage microglia (CD68+). Irrespective of disease, microglia activation was significantly more pronounced and further progressed (CD68+) in brainstem tissues, particularly the medulla, than in the frontal lobe. Whilst survival time from admission marginally significantly correlated with the level of reactive microglia in COVID-19, no associations were found between neuroinflammation and either gender or age at death. Conclusions: Whilst the brainstem demonstrates a disease-independent high susceptibility to inflammation, microglial activation in COVID-19 (COVID-19 microglia encephalopathy) is specific and of importance for understanding the involvement of the CNS in this disease.

SARCOMA MIELOIDE NA LEUCEMIA MIELOIDE AGUDA EM REMISSÃO: RELATO DE CASO

Introdução: O sarcoma mieloide tem incidência variável. Um caso de sarcoma mieloide (SM) em paciente com leucemia mieloide aguda (LMA) em tratamento com doença residual mínima (DRM) negativa será apresentado abaixo, já que preocupa as equipes médicas e se torna desafiador. Relato de caso: Paciente feminina, 21 anos, previamente hígida, queixa de astenia e dor de garganta. Procurou atendimento com 2 dias de evolução, sendo afastada infecção por SARS-CoV-2 e liberada com antibióticos. Cinco dias após houve piora dos sintomas, com astenia e surgimento de linfonodomegalias cervicais. Retornou para atendimento e laboratoriais mostraram: Hb 8,2, Ht 25,2, VCM 93, Leucócitos 90.230, blastos 88%, neutrófilos 1%, eosinófilos 1%, linfócitos 10%, plaquetas 64.000. Internada, foi submetida a análise de medula óssea (MO) que evidenciou infiltração na totalidade por blastos;imunofenotipagem (IFT) indicou LMA com diferenciação monocítica;cariótipo com trissomia do 8. Após citorredução com hidroxiureia, foi submetida a indução com Ara-C e idarrubicina (7+3), apresentando remissão morfológica em 14 dias. Seguiu esquema de consolidação com altas doses de citarabina, com DRM negativa antes do segundo ciclo. Às vésperas da terceira consolidação chega com inúmeras lesões nodulares violáceas. Biópsia da lesão gera imunohistoquímica (IHQ) compatível com sarcoma mieloide com os marcadores: mieloperoxidase, CD68 (KP1), CD33, CD34, CD4 e CD3 positivos e CD20 negativo. Com medula e sangue periférico (SP) negativos, optado por realizar mitoxantrona, etoposide e citarabina, levando a remissão da doença. Discussão e conclusão: De incidência não estabelecida, chegando até 30% de todos os casos de LMA, o SM, conforme a OMS, carecteriza-se pela massa tumoral extramedular formada por blastos mieloides com ou sem maturação. Mas incidente a partir das LMA com diferenciação monocítica, o prognóstico é incerto já que os estudos mostram de desfechos inferiores de sobrevida e tempo livre de doença até não haver mudanças entre as variáveis quando comparados com os desfechos da LMA. O SM possui uma variedade de apresentações: SM sem evidência de leucemia em SP ou MO, SM concomitante a LMA, SM associado a síndrome mielodisplásica, mieloprolifaração ou leucemia mieloide crônica e SM com LMA em remissão. Sendo a pele o principal órgão acometido a migração das células blásticas ainda não é bem compreendida, mas se evidencia relação com a expressão de CD11b, CD56 e da proteína CXCR4 mais frequente nos blastos mielomonocíticos. O diagnóstico deve ser realizado através de biópsia da lesão seguido de IHQ que inclua os marcadores CD33, CD117, MPO, CD34, CD43, CD68 (KP1), CD3, geralmente positivos. Dessa forma pode-se realizar diagnóstico diferencial com outras lesões de pele, principalmente com neoplasia de células dendríticas plasmocitoides blásticas. No estadiamento se fazem importantes os exames de imagem, preferencialmente, PET-CT, e a análise da MO, já que esta última será o critério avaliado para realização do transplante de medula óssea. O tratamento varia de acordo com a concomitância com outras neoplasias hematológicas mas, de maneira geral, os protocolos que incluem Ara-C oferecem remissão completa das lesões de pele. Diante disso, ressalta-se a importância de realizar um bom diagnóstico de forma e conhecer a patologia de forma a tranquilizar a equipe médica em relação aos desfechos.

The Density of CD-68 Positive Macrophages in the Epicardium Correlates with Covid-19 Infection in Deceased Patients

Background: Angiotensin-converting enzyme 2, the target cellular receptor of SARS-CoV-2, is known to be present in adipose tissue. SARS-CoV-2 could enter the heart via the epicardium because the myocardium and the epicardium share the same microcirculation and are not separated from one another by a fascial layer. Previous studies demonstrated that macrophages play an important role in inflammation in adipose, including epicardial, tissue. In this study, we explore two hypotheses: a) there is no significant difference between the density of macrophages in the epicardium of patients who died with Covid-19 infection and those who died with non-Covid-19 acute lung injury, and b) the density of macrophages in the epicardium does not correlate with histological evidence of focal myocyte necrosis in patients who die of Covid-19 infection. Design: We compared the density of macrophages in the epicardium of 10 patients who died of complications of Covid-19 infection to that in a control group of 10 decedents with non-Covid related acute lung injury. Further, macrophage densities of those with and without histological evidence of focal myocardial damage were compared within the Covid-19 group. Three blocks were routinely sampled from each case (right ventricle, left ventricle and septum). All the sections were stained with CD68 as a macrophage marker. The density of CD68-positive cells in the epicardium was determined by counting the number of cells in five hot spot regions (each 3 mm2) at 100x. Quantification was performed using imageJ and is expressed as cells/mm2. The densities of CD68- positive macrophage were compared using T-test. The clinical characteristics between the groups were compared using Fischer exact test. P-value < 0.05 is significant. Results: The density of CD68-positive macrophages in the epicardium is significantly higher in Covid-19 patients compared to the control group. The CD68-macrophage count is also significantly higher in hearts of Covid-19 decedents with histological evidence of focal myocyte necrosis than those with no evidence of myocyte necrosis. There are no significant differences in other characteristics between the groups (Table, Figure). Conclusions: Contrary to our hypotheses, the density of CD68-positive macrophages is strongly correlated with Covid-19 infection and Covid-19 related myocyte necrosis. Further studies are needed to understand the pathophysiologic relationship between epicardial inflammation and myocyte necrosis.

Patterns of Inflammatory Cell Infiltration in the Lungs of Patients with COVID-19, An Autopsy Study

Background: SARS-CoV-2 causes diffuse alveolar damage, lymphocyte infiltration in the lungs and a cytokine storm. In this study we examined inflammatory cell infiltrates in the lungs of patients with COVID-19. Design: Eighteen COVID-19 autopsy cases (COVID group), 9 non-COVID cases with diffuse alveolar damage (DAD, non-COVID group), and eleven controls without lung diseases were included. Immunostainings for CD3, CD4, CD8, CD68 and broad-spectrum keratins were performed. Results: The average age of COVID-19 patients was 64.4±2.1 years. The most common co-morbidities were hypertension (12/17, 70.6%), diabetes mellitus (9/17, 52.9%) and chronic kidney disease (3/17, 17.6%). The survival duration of 17 patients with available clinical information was 21.2 ± 3.4 days (range 7-53 days) after onset of symptoms. Patients younger than 67 years old (namely young patients thereafter, N=9) survived 26.4 ± 5.9 days after onset of symptoms, which was significantly longer than those greater than 67 years old (namely older patients thereafter, 15.2 ± 1.4 days, N=8, P<0.05). The younger patients had significantly lower platelet counts (107.7 ± 33.2 x 109/L, N=8) than the older ones (224.6 ± 42.4 x 109/L, N=8, P<0.05). Conversely, the younger patients had much higher absolute lymphocyte counts (1.5 ± 0.4 x 109/L, N=7) than the older ones (0.7 ± 0.1 x 109/L, N=8, P<0.05). Interestingly, the patients with low platelet counts (<100 x 109/L) survived longer than those with higher platelet counts (P<0.05). Patients with high troponin levels (>0.2 ng/ml) had shorter survival duration after onset of symptoms (16.8 ± 1.9 days) than those with low troponin levels (30.8 ± 8.0 days, P<0.05). Patients with macrophages >130/HPF, CD3+ T cells >145/HPF, CD8+ T cells <30/HPF and CD8+/CD4+ ratio<1 had a shorter survival time compared to those with macrophages <130/HPF, CD3+ T cells <145/HPF, CD8+ T cells >30/HPF and CD8+/CD4+ ratio>1, respectively. Conclusions: Patients' age > 67 years, blood troponin levels >0.2 ng/ml, platelet count >100 x 109/L, lung macrophages >130/HPF, CD3+ T cells >145/HPF, CD8+ T cells <30/HPF, and CD8/CD4 ratio <1 were associated with shorter survival duration after onset of symptoms.

Abstracts from USCAP 2022

The proceedings contain 1298 papers. The topics discussed include: the prevalence of SARS-CoV-2 in autopsy tissue from patients dying without known COVID-19 disease;prevalence of ATTR cardiac amyloidosis in elderly Americans: impact of gender and comparison with a finish population-based autopsy study;effect of the COVID-19 pandemic on autopsy rate;patterns of inflammatory cell infiltration in the lungs of patients with COVID-19, an autopsy study;fatal disseminated coccidioidomycosis: a twenty-year academic hospital's experience of autopsy cases;impact of COVID-19 on autopsy demographics at a safety net hospital;pathologic features of post-acute sequelae of COVID-19 (PASC) at autopsy;histology-proven post-COVID lung fibrosis;cardiac and pulmonary pathology of acute cardiopulmonary events in patients dying in the setting of recent immune checkpoint inhibitor treatment for malignancy;and the density of CD-68 positive macrophages in the epicardium correlates with Covid-19 infection in deceased patients.

Covid-19 myocarditis: Quantitative analysis of the inflammatory infiltrate

Introduction: COVID-19 has a significant effect upon the cardiovascular system including small amounts of myocyte death in some patients resulting in elevated troponin levels. While a number of different cardiovascular histopathologies have been described at post-mortem examination, the incidence of typical viral myocarditis in COVID-19 positive patients appears very low. Hypothesis: We hypothesized that COVID-19 causes a different type of inflammatory cell response that although different, may still cause significant negative effects on the cardiovascular system. Methods: Using immunoperoxidase staining, we characterized and quantified the number of CD3 , CD4 , CD8 , CD68 staining cells in 10 COVID-19 hearts, 10 hearts matched for age and underlying comorbidities, and 5 hearts with autopsy proven typical inflammatory myocarditis. Results: The results demonstrate a skewed distribution of the number of CD68+ cells in COVID-19 hearts, with upper quantiles showing a significant increase as compared to both matched control hearts, and those with myocarditis. In contrast, hearts from typical inflammatory myocarditis contained increased numbers of CD4+, and CD8+ cells compared to both COVID-19 and control cohorts. .

Activation of immune system may cause pathophysiological changes in the myocardium of sarscov-2 infected macaque model

Background: Recent reports suggest the presence of the SARS-CoV-2 virus in the myocardium of patients who died from the COVID-19 disease. Cardiovascular injury in COVID-19 patients is an established extra-pulmonary manifestation of the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection which may lead to induction of arrhythmia, acute heartfailure, thickening of ventricular wall, reduced ejection fraction and thromboembolism. Non-human primates (NHP) provide a useful model to study cardiovascular changes due to their homology to the ACE2 receptor in humans. Aim: The aim of this study is to characterize the pathological changes in the heart of SARS-CoV-2 infected NHPs. Methods: In the present study, SARS-CoV-2 infected primates via aerosol route (n=4), multi-routes (i.e., oral, nasal, intratracheal and conjunctival) (n=4), and a control group (n=5) were included. Heart tissue samples were collected and the left ventricular tissue was analyzed by hematoxylin and eosin, trichrome, and immunohistochemical staining specific to CD3, CD68 andSARS-CoV-2 nucleocapsid protein.Results: Several pathological findings were observed in the heart, including cardiomyocyte disarray, mononuclear infiltrates of inflammatory cells as well as hypertrophy. Collagen specific staining showed development of cardiac fibrosis in the interstitial as well as in the perivascularregion in the hearts of infected primates. Moreover, the myocardial tissue samples displayed multiple foci of inflammatory cells positive for T lymphocytes and macrophages within the myocardium. Additionally, SARS-CoV-2 nucleocapsid protein staining detected the presence of virus particles in the myocardium. Conclusion: COVID19 infection is characterized by exaggerated inflammatory immune response in the heart which possibly contributes to myocardial remodeling and subsequent fibrosis. These findings suggest progression of disease which could lead to development of severe complications including heart failure.

Clinical and morphological characteristics of COVID-19-associated myocarditis

Background: COVID-19 is accompanied by the development of a wide range of cardiovascular lesions. The goal: to study the clinical and morphological features of SARS-CoV-2-associated myocarditis (SCM), determining the presence of viral RNA and proteins in myocardial tissue. Methods: The study was based on 32 autopsies with a confirmed diagnosis of myocarditis. The average age of the patients was 72.7±15.5 years. Men predominated in the group (53%). The immunohistochemical determination of the surface markers of CD45, CD3, CD20, CD 68 inflammatory infiltrates and SARS-CoV-2 nucleocapsid and spike protein has been done. Detection of coronavirus RNA was performed. Results: The clinical manifestations SCM included heart failure and variety of rhythm disturbances. Increased level of anticardiac antibodies was detected. Lymphomacrophage infiltrates (more than 7 CD3+ T-lymphocytes, more than 14 CD45+ lymphocytes and more than 7 CD68+ macrophages per 1 mm2) were found in 100% of cases. RNA of the virus was detected in myocardial tissue. Virus proteins were identified in macrophages of the inflammatory infiltrate and cardiomyocytes. Conclusion: The results suggest persistence of the virus.