Molecular consequences of SARS-CoV-2 liver tropism.

Extrapulmonary manifestations of COVID-19 have gained attention due to their links to clinical outcomes and their potential long-term sequelae1. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) displays tropism towards several organs, including the heart and kidney. Whether it also directly affects the liver has been debated2,3. Here we provide clinical, histopathological, molecular and bioinformatic evidence for the hepatic tropism of SARS-CoV-2. We find that liver injury, indicated by a high frequency of abnormal liver function tests, is a common clinical feature of COVID-19 in two independent cohorts of patients with COVID-19 requiring hospitalization. Using autopsy samples obtained from a third patient cohort, we provide multiple levels of evidence for SARS-CoV-2 liver tropism, including viral RNA detection in 69% of autopsy liver specimens, and successful isolation of infectious SARS-CoV-2 from liver tissue postmortem. Furthermore, we identify transcription-, proteomic- and transcription factor-based activity profiles in hepatic autopsy samples, revealing similarities to the signatures associated with multiple other viral infections of the human liver. Together, we provide a comprehensive multimodal analysis of SARS-CoV-2 liver tropism, which increases our understanding of the molecular consequences of severe COVID-19 and could be useful for the identification of organ-specific pharmacological targets.

Neuropathology of patients with COVID-19 in Germany: a post-mortem case series.

BACKGROUND: Prominent clinical symptoms of COVID-19 include CNS manifestations. However, it is unclear whether severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of COVID-19, gains access to the CNS and whether it causes neuropathological changes. We investigated the brain tissue of patients who died from COVID-19 for glial responses, inflammatory changes, and the presence of SARS-CoV-2 in the CNS. METHODS: In this post-mortem case series, we investigated the neuropathological features in the brains of patients who died between March 13 and April 24, 2020, in Hamburg, Germany. Inclusion criteria comprised a positive test for SARS-CoV-2 by quantitative RT-PCR (qRT-PCR) and availability of adequate samples. We did a neuropathological workup including histological staining and immunohistochemical staining for activated astrocytes, activated microglia, and cytotoxic T lymphocytes in the olfactory bulb, basal ganglia, brainstem, and cerebellum. Additionally, we investigated the presence and localisation of SARS-CoV-2 by qRT-PCR and by immunohistochemistry in selected patients and brain regions. FINDINGS: 43 patients were included in our study. Patients died in hospitals, nursing homes, or at home, and were aged between 51 years and 94 years (median 76 years [IQR 70-86]). We detected fresh territorial ischaemic lesions in six (14%) patients. 37 (86%) patients had astrogliosis in all assessed regions. Activation of microglia and infiltration by cytotoxic T lymphocytes was most pronounced in the brainstem and cerebellum, and meningeal cytotoxic T lymphocyte infiltration was seen in 34 (79%) patients. SARS-CoV-2 could be detected in the brains of 21 (53%) of 40 examined patients, with SARS-CoV-2 viral proteins found in cranial nerves originating from the lower brainstem and in isolated cells of the brainstem. The presence of SARS-CoV-2 in the CNS was not associated with the severity of neuropathological changes. INTERPRETATION: In general, neuropathological changes in patients with COVID-19 seem to be mild, with pronounced neuroinflammatory changes in the brainstem being the most common finding. There was no evidence for CNS damage directly caused by SARS-CoV-2. The generalisability of these findings needs to be validated in future studies as the number of cases and availability of clinical data were low and no age-matched and sex-matched controls were included. FUNDING: German Research Foundation, Federal State of Hamburg, EU (eRARE), German Center for Infection Research (DZIF).

Estimation of the postmortem interval by analyzing potassium in the vitreous humor: could repetitive sampling enhance accuracy?

The relationship between the postmortem interval and the potassium concentration in the vitreous humor has been described by different authors. A limitation of most previous studies might be that all of the vitreous humor has been extracted in 1 sample from different subjects and that the sample was therefore inhomogeneous. In 32 traumatic deaths with known postmortem intervals, small quantities of vitreous humor have been sampled repetitively in 3-hour interval. The bodies were stored at 20°C. The average concentrations of potassium in relation to the postmortem interval were 6.11 to 14.46 mmol/L. An equation that allows accurate prediction of the postmortem interval was established: postmortem interval (h) = 2.749 × [K] - 11.978.

Cytokines and sudden infant death.

BACKGROUND: It has been hypothesised that inflammatory reactions could play an important role in the pathway(s) leading to sudden and unexpected death in infancy. On a molecular level, these reactions are regulated by various cytokines. METHODS: To characterise the role of IL-1ß, IL-6 and TNFα more precisely, the concentrations of these cytokines were determined quantitatively using specific ELISA techniques in serum and cerebrospinal fluid (CSF) in 119 cases of sudden infant death. The infants were grouped into four categories (SIDS, SIDS with infection, natural death due to infection and unnatural death). RESULTS: A good correlation was found between CSF and serum for IL-6 (Spearman correlation coefficients (SCC), 0.73) and also for TNFα (SCC, 0.57), although the CSF concentrations were lower than that from the serum. There were no significant differences between the categories of death for any of the serum or CSF cytokines. Compared with normal values, increased serum concentrations of IL-1ß, IL-6 and TNFα were found in 70%, 69% and 38% of the cases respectively, indicating possible agonal or post-mortem changes of cytokine concentrations. In three cases very high cytokine concentrations were found (mainly for IL-6). This may have contributed to the mechanism of death (cytokine storm) in two of the cases. CONCLUSIONS: In a small group of patients, very high cytokine concentrations are a possible explanation for the cause of death ("cytokine storm").

The German case-control scene investigation study on SIDS: epidemiological approach and main results.

The present study, which was part of the German SIDS Study (GeSID), enrolled sudden infant death syndrome (SIDS) cases and population controls and obtained objective scene data via specifically trained observers shortly after discovery of each dead infant. Infants who had died suddenly and unexpectedly at ages between 8 and 365 days were enrolled in five regions of Germany between November 1998 and October 2001. Shortly after discovery of each dead infant, a specially trained doctor of legal medicine visited the bereaved family at home. Data were obtained by measurements and observations. Dead infants underwent a standardised autopsy, additional information being obtained by standardised parent interviews. Investigation of the sleep environment and wake-up scene in matched controls followed the same protocol. A total of 52 SIDS cases and 154 controls were enrolled, 58% were boys, and median age of cases vs. controls was 126 vs. 129 days. Risk factors in the sleeping environment were pillow use (adjusted OR 4.3; 95%CI 1.6-11.6), heavy duvets (OR 4.4; 1.5-13.3), soft underlay (OR 3.0; 1.1-8.7), face covered by bedding (OR 15.8; 2.5-102.1) and entire body covered by bedding (OR 35.5; 5.5-228.3). Using a standardised protocol, including objective measurements of the sleep environment and a case-control design, this study was able to confirm many risk factors for SIDS.

Avulsion of the left internal mammary artery graft after minimally invasive coronary surgery: fatal complication or medical error? A case report.

Minimally invasive direct coronary artery bypass (MIDCAB) is performed through a left anterior mini-thoracotomy without the use of a cardiopulmonary bypass and offers greater potential for more rapid recovery, reduced pain and a decreased need for blood transfusion than conventional coronary artery bypass grafting. Few major complications of the MIDCAB procedure have been reported in the literature since the first intervention was performed in 1995, but the most serious one is avulsion of the left internal mammary artery (LIMA) graft near the site of anastomosis with the left anterior descending coronary artery. Forensic issues regarding the role of the surgeon in causing this life-threatening emergency condition have not been discussed. We report here the case of a 48-year-old man who died 18 days after a MIDCAB of massive thoracic bleeding due to the avulsion of the LIMA graft. We discuss the probable etiopathogenesis of this fatal complication from a forensic point of view.

Intersecting fractures of the skull and gunshot wounds. Case report and literature review.

When two fracture lines of a solid surface (ice, glass, eggshell, etc.) intersect, it is always possible to tell which one has been made first. Indeed pre-existing damage of the surface arrests all the fracture lines produced by subsequent impacts. This well-known principle (established by Puppe in 1903) has been largely used in glass fracture analysis, but can be applied also to the examination of skull fractures. It can help sequencing blunt force or gunshot injuries determining the direction of fire and differentiating entrance from exit wounds in the absence of specific distinguishing features (i.e., internal/external beveling of the skull or overlying skin indicators). In this context, we report the case of a 76-year-old man who shot himself in the mouth with a Walther PPK 7.65 handgun and highlight the utility of the application of both Puppe's Rule and Multislice Computed Tomography (MSCT) in the examination of gunshot wounds to the skull.

Current recommendations on infants' sleeping position are being followed-initial results of a population-based sentinel study on risk factors for SIDS, 1996-2006, in Hamburg, Germany.

Sudden infant death syndrome (SIDS) is a target for public health care in Germany. The aim of this study was to monitor data on risk-related behavior in the population of Hamburg, Germany, in order to respond to changes quickly and to estimate the effectiveness of prevention activities. Data have been gathered using the sentinel system with repeated surveys (1996, 1998, 2001, and 2006) in pediatric practices, thus allowing an estimate of the prevalence of risk factors in an urban population, both transversally and vertically. From 1996 to 2007, the SIDS rate in Hamburg fell from 0.9/1,000 live births to 0.1. The prevalence of infants sleeping prone declined from 8.1% in 1996 to 3.5% in 2006. In this small subgroup, up to 81.7% (2006) of the caretakers were well aware of the risk of sleeping prone. The prevalence of infants sleeping on their sides fell from 55.3% in 1998 to 10.6% in 2006. The sentinel setting is suitable for gathering risk-related data on SIDS. Despite the fact that, so far, no nationwide back-to-sleep campaign has been instituted in Germany, local campaigns have proved successful in reducing prone sleeping for infants. Moreover, the substantial reduction of side sleeping within a short time span going along with a reduced SIDS rate is an indicator of the effectiveness of prevention activities on a local basis.

Cytomegalovirus-induced pneumonia and myocarditis in three cases of suspected sudden infant death syndrome (SIDS): diagnosis by immunohistochemical techniques and molecularpathologic methods.

Immunohistochemical and molecularpathologic techniques have improved the diagnosis of myocarditis as compared with conventional histologic staining methods done according to the Dallas criteria. Additionally, immunohistochemistry and in situ-hybridization are able to demonstrate viral infection, e.g. cytomegaloviruses in salivary glands and lungs, locations both known to be involved in cytomegalovirusinfection. However, in many cases of proved cytomegalovirusinfection the cause of death remains unclear. We report on three children younger than 1-year of age, who died suddenly without prodromal symptoms. Their deaths were attributed to SIDS (sudden infant death syndrome). In situ-hybridization, immunohistochemical (LCA, CD45R0, CD68, MHC-class-II-molecules, E-selectine) and molecularpathologic investigations (PCR), however, suggested that death was caused by a cytomegalovirus-induced pneumonia or myocarditis. In the future, these methods should be used for investigating cases with suspicion of SIDS.

Pathology of fatal traumatic and nontraumatic clostridial gas gangrene: a histopathological, immunohistochemical, and ultrastructural study of six autopsy cases.

We prospectively investigated six fatal cases of clostridial gas gangrene using autopsy, histology, immunohistochemistry, microbiology, and scanning electron microscopy. The causative pathogen was Clostridium perfringens in four cases, C. sordellii in one case, and a mixed infection with both C. perfringens and C. sordellii in one case. According to the previous medical history and autopsy findings, clostridial infection was related to trauma in three cases. Characterized by extensive tissue necrosis and total absence of an accompanying leukocyte infiltration and tissue inflammatory response, the histopathological picture of clostridial gas gangrene is distinctly different from other bacterial infections. In medicolegal casework, the proof of the source of infection and the portal of entry of the responsible pathogen is not always an easy task, especially in the absence of trauma.

Histological and immunohistochemical study of Wischnewsky spots in fatal hypothermia.

Wischnewsky spots in the gastric mucosa are considered an important finding for the diagnosis of hypothermia-related deaths. In the present prospective histological and immunohistochemical investigation, 14 cases of fatal hypothermia presenting Wischnewsky spots at autopsy were studied. Macromorphologically, the lesions, varying in diameter from 0.1 to 0.4 cm, had a blackish-brownish color and appeared partly lofty, especially on the apex of gastric folds. Histologically, no erosions or ulcers were observed in the gastric mucosa. In some cases, hemorrhages in conjunction with infarctions of the mucosa were observed in the mucosal glands. Those regions, however, did not represent the lesions visible as Wischnewsky spots at the macroscopical level. Immunohistochemical stains were done with a specific antibody against hemoglobin (Dako, Glostrup, Denmark). Wischnewsky spots expressed immunopositivity with antihemoglobin. Concerning the pathogenesis and underlying pathophysiologic mechanisms contributing to the development of Wischnewsky spots, we hypothesize that cooling of the body in the setting of cold ambient temperatures primarily leads to circumscribed hemorrhages of the gastric glands in vivo or in the agonal period, respectively. Subsequently, due to autolysis, erythrocytes are destroyed and hemoglobin is released. Following exposure to gastric acid, hemoglobin is hematinized, leading to the typical blackish-brownish appearance of Wischnewsky spots seen at gross examination. Wischnewsky spots are not equivalent to erosions in terms of histopathological diagnosis but rather represent epiphenomena generated in vivo or in the agonal period of fatal hypothermia.

Morphometrical, histopathological, immunohistochemical, and ultrastructural findings in human pulmonary tissue destruction following penetrating low-velocity firearm injuries to the lungs.

This autopsy-based study investigated the morphological correlates of pulmonary tissue destruction following fatal penetrating gunshot wounds to the lungs using morphometry, histology, immunohistochemistry, and scanning electron microscopy on whole human lungs fixed-expanded via formalin inflation. As the residue of temporary cavity formation, mantle-like hemorrhagic destruction zones were seen surrounding the missile track that showed an eccentric, conical extension enlarging toward subpleural lung segments. In addition, circumscribed, satellite-like bleeding zones at distances of up to 5.5 cm beyond the border of the permanent cavity were observed that corresponded to interstitial perivascular hemorrhages around larger and smaller pulmonary vessels on the micro-morphological level. These multifocal hemorrhages within macroscopically unaffected parts of pulmonary tissue at some distance from the actual missile track may represent unrecognized, life-threatening intrapulmonary bleeding sources in survivors, potentially leading to ventilation-perfusion mismatch and progressive lung failure. A further noticeable microscopic and ultrastructural finding was that of club-shaped distensions of ruptured alveolar septa strictly limited to the extent of the temporary cavity. These club-shaped distensions of ruptured alveolar septa seem to represent a special feature of alveolar architectural damage that can be explained by the dynamics of the temporary cavity formation: the radial acceleration and overdistension of tissue during temporary cavitation initiates stretch mechanisms of the displaced tissue, causing the alveolar septa to rupture with subsequent foreshortening and pursing of elastic alveolar fibers.

Coma blisters in a case of fatal theophylline intoxication.

A case of fatal poisoning caused by theophylline toxicity (serum level 127 micro g/ml) is presented. At external examination, skin blisters on regions exposed to pressure were distinctive. Histologic examination demonstrated subepidermal bullae with eosinophilic necrosis of the eccrine sweat gland coil but no epidermal necrosis, vascular changes, or inflammatory infiltrate. To the authors' knowledge, this is the first description of coma blisters in a case of theophylline intoxication.

Pseudomembranous colitis with fatal outcome in a 43-year-old man.

Pseudomembranous colitis is a life-threatening complication of broad spectrum antibiotic therapy caused by Clostridium difficile. Untreated, the disease can lead to severe and in many cases fatal complications such as peritonitis due to colonic wall perforation, shock as a consequence of volume depletion, toxic megacolon and massive lower gastrointestinal haemorrhage. Fatal complications mostly occur in elderly people with a high degree of comorbidity. We report the case of a 43-year-old patient with AIDS who was admitted to hospital with abdominal pain of unknown origin and died before the correct diagnosis could be established. Autopsy and postmortem stool cultures revealed severe pseudomembranous colitis due to C. difficile with toxic cardiac and circulatory failure as cause of death.