Infection by the new corona virus strain SARS-CoV-2 and its related syndrome COVID-19 has been associated with more than two million deaths worldwide. Patients of higher age and with preexisting ...chronic health conditions are at an increased risk of fatal disease outcome. However, detailed information on causes of death and the contribution of pre-existing health conditions to death yet is missing, which can be reliably established by autopsy only. We performed full body autopsies on 26 patients that had died after SARS-CoV-2 infection and COVID-19 at the Charité University Hospital Berlin, Germany, or at associated teaching hospitals. We systematically evaluated causes of death and pre-existing health conditions. Additionally, clinical records and death certificates were evaluated. We report findings on causes of death and comorbidities of 26 decedents that had clinically presented with severe COVID-19. We found that septic shock and multi organ failure was the most common immediate cause of death, often due to suppurative pulmonary infection. Respiratory failure due to diffuse alveolar damage presented as immediate cause of death in fewer cases. Several comorbidities, such as hypertension, ischemic heart disease, and obesity were present in the vast majority of patients. Our findings reveal that causes of death were directly related to COVID-19 in the majority of decedents, while they appear not to be an immediate result of preexisting health conditions and comorbidities. We therefore suggest that the majority of patients had died of COVID-19 with only contributory implications of preexisting health conditions to the mechanism of death.
Myalgia, increased levels of creatine kinase, and persistent muscle weakness have been reported in patients with COVID-19.
To study skeletal muscle and myocardial inflammation in patients with ...COVID-19 who had died.
This case-control autopsy series was conducted in a university hospital as a multidisciplinary postmortem investigation. Patients with COVID-19 or other critical illnesses who had died between March 2020 and February 2021 and on whom an autopsy was performed were included. Individuals for whom informed consent to autopsy was available and the postmortem interval was less than 6 days were randomly selected. Individuals who were infected with SARS-CoV-2 per polymerase chain reaction test results and had clinical features suggestive of COVID-19 were compared with individuals with negative SARS-CoV-2 polymerase chain reaction test results and an absence of clinical features suggestive of COVID-19.
Inflammation of skeletal muscle tissue was assessed by quantification of immune cell infiltrates, expression of major histocompatibility complex (MHC) class I and class II antigens on the sarcolemma, and a blinded evaluation on a visual analog scale ranging from absence of pathology to the most pronounced pathology. Inflammation of cardiac muscles was assessed by quantification of immune cell infiltrates.
Forty-three patients with COVID-19 (median interquartile range age, 72 16 years; 31 men 72%) and 11 patients with diseases other than COVID-19 (median interquartile range age, 71 5 years; 7 men 64%) were included. Skeletal muscle samples from the patients who died with COVID-19 showed a higher overall pathology score (mean SD, 3.4 1.8 vs 1.5 1.0; 95% CI, 0-3; P < .001) and a higher inflammation score (mean SD, 3.5 2.1 vs 1.0 0.6; 95% CI, 0-4; P < .001). Relevant expression of MHC class I antigens on the sarcolemma was present in 23 of 42 specimens from patients with COVID-19 (55%) and upregulation of MHC class II antigens in 7 of 42 specimens from patients with COVID-19 (17%), but neither were found in any of the controls. Increased numbers of natural killer cells (median interquartile range, 8 8 vs 3 4 cells per 10 high-power fields; 95% CI, 1-10 cells per 10 high-power fields; P < .001) were found. Skeletal muscles showed more inflammatory features than cardiac muscles, and inflammation was most pronounced in patients with COVID-19 with chronic courses. In some muscle specimens, SARS-CoV-2 RNA was detected by reverse transcription-polymerase chain reaction, but no evidence for a direct viral infection of myofibers was found by immunohistochemistry and electron microscopy.
In this case-control study of patients who had died with and without COVID-19, most individuals with severe COVID-19 showed signs of myositis ranging from mild to severe. Inflammation of skeletal muscles was associated with the duration of illness and was more pronounced than cardiac inflammation. Detection of viral load was low or negative in most skeletal and cardiac muscles and probably attributable to circulating viral RNA rather than genuine infection of myocytes. This suggests that SARS-CoV-2 may be associated with a postinfectious, immune-mediated myopathy.
Abstract
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causing coronavirus disease 2019 (COVID-19) induces lung injury of varying severity, potentially causing severe acute respiratory ...distress syndrome (ARDS). Pulmonary injury patterns in COVID-19 patients differ from those in patients with other causes of ARDS. We aimed to explore the frequency and pathogenesis of cavitary lung lesions in critically ill patients with COVID-19. Retrospective study in 39 critically ill adult patients hospitalized with severe acute respiratory syndrome coronavirus 2 including lung injury of varying severity in a tertiary care referral center during March and May 2020, Berlin/Germany. We observed lung cavitations in an unusually large proportion of 22/39 (56%) COVID-19 patients treated on intensive care units (ICU), including 3/5 patients without mechanical ventilation. Median interquartile range (IQR) time between onset of symptoms and ICU admission was 11.5 (6.25–17.75) days. In 15 patients, lung cavitations were already present on the first CT scan, performed after ICU admission; in seven patients they developed during a subsequent median (IQR) observation period of 48 (35–58) days. In seven patients we found at least one cavitation with a diameter > 2 cm (maximum 10 cm). Patients who developed cavitations were older and had a higher body mass index. Autopsy findings in three patients revealed that the cavitations reflected lung infarcts undergoing liquefaction, secondary to thrombotic pulmonary artery branch occlusions. Lung cavitations appear to be a frequent complication of severely ill COVID-19 patients, probably related to the prothrombotic state associated with COVID-19.
We present a case of a male patient in his mid-30s with COVID-19-induced lung failure requiring extracorporeal membrane oxygenation, who needed an emergency oesophagogastroduodenoscopy due to major ...upper gastrointestinal bleeding. Endoscopy exposed severe ulcerative duodenitis with diffuse mucosal bleeding. While CT angiography did not show any signs of ischaemia, histopathology revealed duodenitis with substantial inflammatory cell infiltrates consisting of neutrophils and CD3+ T lymphocytes with equal CD4+/CD8+ distribution. Since the composition of cell infiltrates coincides with changes in inflammatory patterns of the respiratory mucosa from patients with COVID-19 and in COVID-19-associated enterocolitis, and systemic dexamethasone treatment became standard of care in ventilated intensive care unit patients with COVID-19 infection, we initiated an individualised therapeutic attempt to treat the duodenitis with topical enteral budesonide. Follow-up oesophagogastroduodenoscopies within 4 weeks of enteral budesonide administration revealed a full clinical and histological healing of the duodenal mucosa with marked reduction of neutrophilic and lymphocytic infiltrates.To our knowledge, the current report is the first description of enteral budesonide treatment of duodenitis in a patient with COVID-19 infection and warrants further investigation, whether budesonide might constitute a novel therapeutic strategy for the management of COVID-19-related intestinal mucosal damage.
•Pre-existing medical conditions increase the risk of fatal COVID-19 in younger adults.•Younger and healthy COVID-19 patients may develop serious health conditions.•Younger COVID-19 patients are ...prone to thromboembolic complications.
Studies on coronavirus disease 2019 (COVID-19) usually focus on middle-aged and older adults. However, younger patients may present with severe COVID-19 with potentially fatal outcomes. For optimized, more specialized therapeutic regimens in this particular patient group, a better understanding of the underlying pathomechanisms is of utmost importance.
Our study investigated relevant, pre-existing medical conditions, clinical histories, and autopsy findings, together with SARS-CoV-2-RNA, determined by qPCR, and laboratory data in six COVID-19 decedents aged 50 years or younger, who were autopsied at the Charité University Hospital.
From a total of 76 COVID-19 patients who underwent an autopsy at our institution, six (7.9%) were 50 years old or younger. Most of these younger COVID-19 decedents presented with pre-existing medical conditions prior to SARS-CoV-2 infection. These included overweight and obesity, arterial hypertension, asthma, and obstructive sleep apnea, as well as graft-versus-host disease following cancer and bone marrow transplantation. Furthermore, clinical histories and autopsy results revealed a disproportionally high prevalence of thromboembolism and ischemic organ damage in this patient cohort. Histopathology and laboratory results indicated coagulopathies, signs of immune dysregulation, and liver damage.
In conclusion, pre-existing health conditions may increase the risk of severe and fatal COVID-19 in younger patients, who may be especially prone to developing thromboembolic complications, immune dysregulation, and liver damage.
•Lymphocytopenia in COVID-19 decedents is accompanied by B cell depletion in bone marrow and spleen.•COVID-19 decedents with B cell loss show a tendency towards higher pulmonary SARS-CoV-2 ...burden.•Loss of B cells and plasma cells may impede the humoral immune response to SARS-CoV-2.•COVID-19 decedents show signs of sepsis-induced immunodeficiency in the bone marrow.
In coronavirus disease 2019 (COVID-19), the adaptive immune response is of considerable importance, and detailed cellular immune reactions in the hematological system of patients with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection are yet to be clarified.
This study reports the morphological characterization of both bone marrow and spleen in 11 COVID-19 decedents with respect to findings in the peripheral blood and pulmonary SARS-CoV-2 burden.
In the bone marrow, activation and left shift were found in at least 55% of patients, which was mirrored by peripheral anaemia, granulocytic immaturity and multiple thromboembolic events. Signs of sepsis-acquired immunodeficiency were found in the setting of an abscess-forming superinfection of viral COVID-19 pneumonia. Furthermore, a severe B cell loss was observed in the bone marrow and/or spleen in 64% of COVID-19 patients. This was reflected by lymphocytopenia in the peripheral blood. As compared to B cell preservation, B cell loss was associated with a higher pulmonary SARS-CoV-2 burden and only a marginal decrease of of T cell counts.
The results of this study suggest the presence of sepsis-related immunodeficiency in severe COVID-19 pneumonia with superinfection. Furthermore, our findings indicate that lymphocytopenia in COVID-19 is accompanied by B cell depletion in hematopoietic tissue, which might impede the durability of the humoral immune response to SARS-CoV-2.
The derivation of hepatocytes from human induced pluripotent stem cells (hiPSC) is of great interest for applications in pharmacological research. However, full maturation of hiPSC-derived ...hepatocytes has not yet been achieved in vitro. To improve hepatic differentiation, co-cultivation of hiPSC with human umbilical vein endothelial cells (HUVEC) during hepatic differentiation was investigated in this study. In the first step, different culture media variations based on hepatocyte culture medium (HCM) were tested in HUVEC mono-cultures to establish a suitable culture medium for co-culture experiments. Based on the results, two media variants were selected to differentiate hiPSC-derived definitive endodermal (DE) cells into mature hepatocytes with or without HUVEC addition. DE cells differentiated in mono-cultures in the presence of those media variants showed a significant increase (
< 0.05) in secretion of α-fetoprotein and in activities of cytochrome P450 (CYP) isoenzymes CYP2B6 and CYP3A4 as compared with cells differentiated in unmodified HCM used as control. Co-cultivation with HUVEC did not further improve the differentiation outcome. Thus, it can be concluded that the effect of the used medium outweighed the effect of HUVEC co-culture, emphasizing the importance of the culture medium composition for hiPSC differentiation.
Remimazolam is an ultra-short acting benzodiazepine under development for procedural sedation and general anesthesia. It is hydrolyzed by CES1 to an inactive metabolite (CNS7054).
In this study, the ...effect of continuous remimazolam exposure on its metabolism and on
expression was investigated in a dynamic 3-D bioreactor culture model inoculated with primary human hepatocytes.
Remimazolam was continuously infused into bioreactors for 5 days at a final concentration of 3,000 ng/ml (6.8 µM). In parallel, 2-D cultures were run with cells from the same donors, but with discontinuous exposure to remimazolam.
Daily measurement of clinical chemistry parameters (glucose, lactate, urea, ammonia, and liver enzymes) in culture supernatants indicated no noxious effect of remimazolam on hepatocyte integrity as compared to untreated controls. Concentrations of remimazolam reached steady-state values of around 250 ng/ml within 8 hours in 3-D bioreactors whereas in 2-D cultures remimazolam concentrations declined to almost zero within the same time frame. Levels of CNS7054 showed an inverse time-course reaching average values of 1,350 ng/ml in perfused 3-D bioreactors resp. 2,800 ng/ml in static 2-D cultures. Analysis of mRNA expression levels of
indicated no changes in gene expression over the culture period.
The results indicated a stable metabolism of remimazolam during 5 days of continuous exposure to clinically relevant concentrations of the drug. Moreover, there was no evidence for a harmful effect of remimazolam exposure on the integrity and metabolic activity of in vitro cultivated primary human hepatocytes.
Objective
For optimized expansion of human‐induced pluripotent stem cells (hiPSCs) with regards to clinical applications, we investigated the influence of the inoculum density on the expansion ...procedure in 3D hollow‐fibre bioreactors.
Materials and Methods
Analytical‐scale bioreactors with a cell compartment volume of 3 mL or a large‐scale bioreactor with a cell compartment volume of 17 mL were used and inoculated with either 10 × 106 or 50 × 106 hiPSCs. Cells were cultured in bioreactors over 15 days; daily measurements of biochemical parameters were performed. At the end of the experiment, the CellTiter‐Blue® Assay was used for culture activity evaluation and cell quantification. Also, cell compartment sections were removed for gene expression and immunohistochemistry analysis.
Results
The results revealed significantly higher values for cell metabolism, cell activity and cell yields when using the higher inoculation number, but also a more distinct differentiation. As large inoculation numbers require cost and time‐extensive pre‐expansion, low inoculation numbers may be used preferably for long‐term expansion of hiPSCs. Expansion of hiPSCs in the large‐scale bioreactor led to a successful production of 5.4 × 109 hiPSCs, thereby achieving sufficient cell amounts for clinical applications.
Conclusions
In conclusion, the results show a significant effect of the inoculum density on cell expansion, differentiation and production of hiPSCs, emphasizing the importance of the inoculum density for downstream applications of hiPSCs. Furthermore, the bioreactor technology was successfully applied for controlled and scalable production of hiPSCs for clinical use.
The accurate prediction of hepatotoxicity demands validated human in vitro models that can close the gap between preclinical animal studies and clinical trials. In this study we investigated the ...response of primary human liver cells to toxic drug exposure in a perfused microscale 3D liver bioreactor. The cellularized bioreactors were treated with 5, 10, or 30 mM acetaminophen (APAP) used as a reference substance. Lactate production significantly decreased upon treatment with 30 mM APAP (
< 0.05) and ammonia release significantly increased in bioreactors treated with 10 or 30 mM APAP (
< 0.0001), indicating APAP-induced dose-dependent toxicity. The release of prostaglandin E2 showed a significant increase at 30 mM APAP (
< 0.05), suggesting an inflammatory reaction towards enhanced cellular stress. The expression of genes involved in drug metabolism, antioxidant reactions, urea synthesis, and apoptosis was differentially influenced by APAP exposure. Histological examinations revealed that primary human liver cells in untreated control bioreactors were reorganized in tissue-like cell aggregates. These aggregates were partly disintegrated upon APAP treatment, lacking expression of hepatocyte-specific proteins and transporters. In conclusion, our results validate the suitability of the microscale 3D liver bioreactor to detect hepatotoxic effects of drugs in vitro under perfusion conditions.
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