Multiplatform analyses reveal distinct drivers of systemic pathogenesis in adult versus pediatric severe acute COVID-19.

The pathogenesis of multi-organ dysfunction associated with severe acute SARS-CoV-2 infection remains poorly understood. Endothelial damage and microvascular thrombosis have been identified as drivers of COVID-19 severity, yet the mechanisms underlying these processes remain elusive. Here we show alterations in fluid shear stress-responsive pathways in critically ill COVID-19 adults as compared to non-COVID critically ill adults using a multiomics approach. Mechanistic in-vitro studies, using microvasculature-on-chip devices, reveal that plasma from critically ill COVID-19 adults induces fibrinogen-dependent red blood cell aggregation that mechanically damages the microvascular glycocalyx. This mechanism appears unique to COVID-19, as plasma from non-COVID sepsis patients demonstrates greater red blood cell membrane stiffness but induces less significant alterations in overall blood rheology. Multiomics analyses in pediatric patients with acute COVID-19 or the post-infectious multi-inflammatory syndrome in children (MIS-C) demonstrate little overlap in plasma cytokine and metabolite changes compared to adult COVID-19 patients. Instead, pediatric acute COVID-19 and MIS-C patients show alterations strongly associated with cytokine upregulation. These findings link high fibrinogen and red blood cell aggregation with endotheliopathy in adult COVID-19 patients and highlight differences in the key mediators of pathogenesis between adult and pediatric populations.

Is it COVID-19? The value of medicolegal autopsies during the first year of the COVID-19 pandemic.

OBJECTIVES: We describe the experience of a busy metropolitan medical examiner's office in the United States and share our navigation of the COVID-19 autopsy decision-making process. We describe key gross and microscopic findings that, with appropriate laboratory testing, should direct a pathologist towards a COVID-19-related cause of death. MATERIAL AND METHODS: We performed a retrospective review of 258 suspected and/or confirmed COVID-19 associated deaths that occurred between March 5, 2020, and March 4, 2021. RESULTS: A total of 62 cases due to fatal COVID-19 were identified; autopsy findings included diffuse alveolar damage, acute bronchopneumonia and lobar pneumonia, and pulmonary thromboemboli. Nine additional decedents had a nasopharyngeal swab positive for SARS-CoV-2 and a cause of death unrelated to COVID-19. Forty-seven cases with COVID-19-like symptoms showed no laboratory or histopathologic evidence of SARS-CoV-2 infection; the most common causes of death in this group were hypertensive or atherosclerotic cardiovascular disease, complications of chronic alcoholism, and pulmonary thromboemboli unrelated to infection. CONCLUSIONS: The clinical findings associated with COVID-19 are not specific; a broad differential diagnosis should be embraced when decedents present with cough or shortness of breath. An autopsy may be indicated to identify a cause of death unrelated to COVID-19.

Diagnosing Anal Squamous Intraepithelial Lesions With and Without p16: An Interobserver Variability Study.

OBJECTIVE: Morphologic diagnosis and grading of anal squamous intraepithelial lesions (ASILs) are challenging. In this study, we investigated interobserver variability and p16 utility in accurately grading anal SIL. MATERIALS AND METHODS: Six pathologists evaluated the degree of SIL on hematoxylin and eosin slides from 146 anal biopsies, followed by the review of both p16 and hematoxylin and eosin slides in cases where p16 was previously performed. κ was calculated in the following 4 ways: (A) 4-tiered diagnosis (negative for SIL [NSIL], anal intraepithelial neoplasia [AIN 1, AIN 2, AIN 3]); (B) 3-tiered diagnosis (NSIL and AIN 1 [pooled], AIN 2, AIN 3); (A) 3-tiered diagnosis (NSIL, low-grade SIL, high-grade SIL [HSIL]); and (D) 2-tiered diagnosis (no HSIL, HSIL). RESULTS: There is only moderate agreement with a 4-tiered diagnosis with or without p16 (κ = 0.48-0.57). There is substantial agreement when AIN 2 and AIN 3 are pooled as HSIL in cases with or without p16 review (κ = 0.71-0.78). There is almost perfect agreement with a 2-tiered diagnosis of negative for HSIL and HSIL both in cases where p16 was used and where p16 was not required, with the best agreement for a 2-tiered diagnosis with concurrent p16 review. CONCLUSIONS: This study highlights the importance of a judicious use of p16 for diagnosis. When there is no need for p16 by the Lower Anogenital Squamous Terminology guidelines, interobserver agreement was substantial to almost perfect with a 2-tiered diagnosis. However, when its use is indicated but it is not performed or reviewed, the agreement is much lower even with a 2-tiered diagnosis. Rational use of p16 will ensure diagnostic accuracy and the best possible patient care.

Original Research: Diametric effects of hypoxia on pathophysiology of sickle cell disease in a murine model.

Hypoxia causes erythrocyte sickling in vitro; however, its role in the pathophysiology of sickle cell disease is poorly understood. We report that hypoxia rapidly decreased oxygen saturation in transgenic sickle cell disease mice, but this effect was immediately buffered by a robust ventilatory response. The initial hypoxemia improved steadily throughout the duration of hypoxia without any detectable acute pulmonary adverse effect. Furthermore, the mice suffered acute anemia that ironically was associated with lowering of both plasma hemoglobin and heme. These results were corroborated by increased plasma haptoglobin and hemopexin levels. Markers of ischemic tissue injury increased spatiotemporally following repeated hypoxia exposures. This variation was supported by organ-specific induction of hypoxia-responsive genes. Our results show that hypoxia exerts diametric effects on sickle cell disease by promoting ischemic injury while enhancing the expression of hemolysis scavenger molecules. This phenomenon may help to understand the disparate clinical syndromes associated with hemolysis and vaso-occlusion in sickle cell disease.

Fatal aortic pseudoaneurysm from disseminated Mycobacterium kansasii infection: case report.

Mycobacterium kansasii is a photochromogenic, slow-growing mycobacterium species that can cause pulmonary infection in patients with predisposing lung diseases, as well as extrapulmonary or disseminated disease in immunosuppressed patients. We describe a patient with a myelodysplastic syndrome, disseminated M kansasii infection, and ruptured aortic aneurysm. He had a recent diagnosis of mycobacterium cavitary lung lesions and was transferred to our facility for possible surgical intervention of an aortic aneurysm. Few hours after admission, the patient suddenly collapsed and died despite resuscitation efforts. A complete autopsy was performed and showed ruptured ascending aortic pseudoaneurysm with hemopericardium, disseminated necrotizing and nonnecrotizing granulomas with acid-fast bacilli in the aortic wall, lungs, heart, liver, spleen, and kidneys. Further genetic studies were consistent with monocytopenia and mycobacterial infection syndrome.

Global gene expression profiling of endothelium exposed to heme reveals an organ-specific induction of cytoprotective enzymes in sickle cell disease.

BACKGROUND: Sickle cell disease (SCD) is characterized by hemolysis, vaso-occlusion and ischemia reperfusion injury. These events cause endothelial dysfunction and vasculopathies in multiple systems. However, the lack of atherosclerotic lesions has led to the idea that there are adaptive mechanisms that protect the endothelium from major vascular insults in SCD patients. The molecular bases for this phenomenon are poorly defined. This study was designed to identify the global profile of genes induced by heme in the endothelium, and assess expression of the heme-inducible cytoprotective enzymes in major organs impacted by SCD. METHODS AND FINDINGS: Total RNA isolated from heme-treated endothelial monolayers was screened with the Affymetrix U133 Plus 2.0 chip, and the microarray data analyzed using multiple bioinformatics software. Hierarchical cluster analysis of significantly differentially expressed genes successfully segregated heme and vehicle-treated endothelium. Validation studies showed that the induction of cytoprotective enzymes by heme was influenced by the origin of endothelial cells, the duration of treatment, as well as the magnitude of induction of individual enzymes. In agreement with these heterogeneities, we found that induction of two major Nrf2-regulated cytoprotective enzymes, heme oxygenase-1 and NAD(P)H:quinone oxidoreductase-1 is organ-specific in two transgenic mouse models of SCD. This data was confirmed in the endothelium of post-mortem lung tissues of SCD patients. CONCLUSIONS: Individual organ systems induce unique profiles of cytoprotective enzymes to neutralize heme in SCD. Understanding this heterogeneity may help to develop effective therapies to manage vasculopathies of individual systems.

Improvement in cardiac function with small intestine extracellular matrix is associated with recruitment of C-kit cells, myofibroblasts, and macrophages after myocardial infarction.

OBJECTIVES: This study tested the hypothesis that modulation of angiogenesis and cardiac function by injecting small intestine extracellular matrix emulsion (EMU) into myocardium is associated with recruitment of c-kit cells, myofibroblasts, and macrophages after myocardial infarction. BACKGROUND: Degradation of native extracellular matrix has been associated with adverse cardiac remodeling after infarction. METHODS: Sixty-four rats were subjected to 45 min ischemia followed by 3, 7, 21, and 42 days of reperfusion, respectively. Saline or EMU (30 to 50 microl) was injected into the area at risk myocardium after reperfusion. Histological examination was performed by immunohistochemical staining, and cardiac function was analyzed using echocardiography. RESULTS: The population of c-kit-positive cells in infarcted myocardium with the EMU injection increased significantly relative to the saline control at 7 days of reperfusion. Along with this change, alpha-smooth muscle actin expressing myofibroblasts and macrophages accumulated to a significant extent compared with the saline control. Increased vascular endothelial growth factor protein level and strong immunoreactivity of vascular endothelial growth factor expression were observed. Angiogenesis in the EMU area was significantly enhanced relative to the saline control, evidenced by increased density of alpha-smooth muscle actin positive vessels. Furthermore, echocardiography showed significant improvements in fractional shortening, ejection fraction, and stroke volume in the EMU group. The wall thickness of the infarcted middle anterior septum in the EMU group was significantly increased relative to the saline control. CONCLUSIONS: We show for the first time that injection of EMU into the infarcted myocardium increases neovascularization and preserves cardiac function, potentially mediated by enhanced recruitment of c-kit-positive cells, myofibroblasts, and macrophages.

A rare case of squamous cell carcinoma of the bladder presenting as a metastatic right ventricular mass.

A 74-year-old woman presented with bilateral lower extremity swelling, worsening dyspnea on exertion, and mild hemoptysis. An echocardiogram at time of admission showed a mass in the right ventricle. The pathology of a sample obtained via transvenous biopsy was consistent with squamous cell carcinoma; no primary source could initially be identified. Severe thrombocytopenia, likely consumptive, precluded surgical intervention, so the patient underwent palliative radiation. Unfortunately, she developed fatal respiratory failure. Upon autopsy, the bladder was found to contain polyps of invasive squamous cell carcinoma, similar in morphology to the tumor mass in the heart. Her lungs contained multiple tumor emboli at different stages, which was likely the final cause of her death. Squamous cell carcinoma metastases to the endocardium are extremely rare and without defined treatment. Surgery can improve prognosis in those with primary tumors that are benign or without metastases. In those with symptomatic metastatic tumors, palliative debulking can done although generally will not improve prognosis. It is currently unknown whether radiation improves survival. In this case, irradiation did destroy a portion of the tumor as the final pathology showed extensive necrosis of the tumor; unfortunately, it did not change her symptoms and did not change the final outcome.

Attenuation of renal ischemia-reperfusion injury by postconditioning involves adenosine receptor and protein kinase C activation.

SUMMARY: Significant organ injury occurs after transplantation and reflow (i.e., reperfusion injury). Postconditioning (PoC), consisting of alternating periods of reperfusion and re-occlusion at onset of reperfusion, attenuates reperfusion injury in organs including heart and brain. We tested whether PoC attenuates renal ischemia-reperfusion (I/R) injury in the kidney by activating adenosine receptors (AR) and protein kinase C (PKC). The single kidney rat I/R model was used. Groups: (1) sham: time-matched surgical protocol only. In all others, the left renal artery (RA) was occluded for 45 min and reperfused for 24 h. (2) CONTROL: I/R with no intervention at R. All antagonists were administered 5 min before reperfusion. (3) PoC: I/R + four cycles of 45 s of R and 45 s of re-occlusion before full R. (4) PoC + ARi: PoC plus the AR antagonist 8-rho-(sulfophenyl) theophylline (8-SPT). (5) PoC + PKCi: PoC plus the PKC antagonist chelerythrine (Che). In shams, plasma blood urea nitrogen (BUN mg/dl) at 24 h averaged 23.2 +/- 5.3 and creatinine (Cr mg/dl) averaged 1.28 +/- 0.2. PoC reduced BUN (87.2 +/- 10 in CONTROL vs. 38.8 +/- 9, P = 0.001) and Cr (4.2 +/- 0.6 in CONTROL vs. 1.5 +/- 0.2, P < 0.001). 8-SPT and Che reversed renal protection indices after PoC. I/R increased apoptosis, which was reduced by PoC, which was reversed by 8-SPT and Che. Postconditioning attenuates renal I/R injury by adenosine receptor activation and PKC signaling.

Unusual presentation of anaplastic large cell lymphoma with clinical course mimicking fever of unknown origin and sepsis: autopsy study of five cases.

AIM: To describe a subset of cases with the unusual clinical and histomorphological presentation of anaplastic large cell lymphoma (ALCL) mimicking fever of unknown origin (FUO) and sepsis. METHODS: A pathology database was searched using full term Systematized Nomenclature of Medicine codes for ALCL to identify 23ALCL cases from the period 1999-2006. Of those, five cases that did not have a correct premortem diagnosis were further analyzed to elucidate the reasons for delayed and incorrect pre-mortem diagnosis. The analyzed data included clinical presentation, duration of symptoms, duration of hospital stay, premortem presumed cause of death, white blood cell count, platelet count, anion gap and blood pH, liver enzymes (alanine aminotransferase, aspartate aminotransferase, lactate dehydrogenase, alkaline phosphatase), lactate, coagulation tests (prothrombin time, partial thromboplastin time, fibrinogen, D-dimers), microbiology cultures, and radiology and surgical pathology reports. Autopsy reports were reviewed for description of major gross findings, initial clinical diagnosis, and cause of death. RESULTS: Five fatal and pre-mortem unrecognized ALCL cases were characterized by rapid decline, with histologic findings showing predominantly extranodal involvement, intravascular lymphomatosis, and hemophagocytosis. The cases were also characterized by unusual clinical manifestations including a FUO, sepsis, and disseminated intravascular coagulation-like picture, lactic acidosis, hepatosplenomegaly, and absence of significant peripheral adenopathy. CONCLUSIONS: There is a distinct group of ALCLs with unique and specific clinical, gross autopsy, and histopathologic findings. Recognition of this clinical variant may facilitate early detection and potentially timely diagnosis and therapy.

Combined pathological effects of cocaine abuse and HIV infection on the cardiovascular system: an autopsy study of 187 cases from the Fulton County Medical Examiner's office.

This autopsy study evaluates the possible cumulative effects of cocaine use in HIV-infected adult individuals on cardiovascular tissue. A total of 187 autopsy case reports and available H&E sections of myocardium and coronary arteries were reviewed. Four major study groups were defined: (A) a total of 63 cases positive for cocaine and negative for HIV (COC); (B) 40 cases positive for HIV/AIDS and negative for cocaine (HIV), (C) 23 cases both HIV/AIDS and cocaine (HIV/COC), and (D) a control group of 61 age-, sex- and race-matched, negative for cocaine and for HIV (CONT). The following morphologic and demographic data were analyzed: heart weight, left ventricular hypertrophy, myocardial fibrosis, thickening of the intramyocardial vessels, myocarditis, acute or remote myocardial infarcts (MI), age, sex, and race. Increased frequency of coronary wall and adventitial infiltrates, myocarditis, and thickened intramyocardial vessels present in HIV/COC group (14.5%, 17.4%, and 17.4% vs. 6.5%, 3.3%, and 0% in CONT group) may indicate possible combined and/or cumulative effects of HIV and cocaine on cardiovascular pathology.

Sickle cell lung disease and sudden death: a retrospective/prospective study of 21 autopsy cases and literature review.

Sudden death in the setting of sickle cell lung disease (SCLD), is periodically seen in the practice of medical examiners. The goal of the present study was to identify the most common pathologic findings of SCLD associated with sudden or unexpected death. A retrospective/prospective review of 21 autopsy cases from sickle cell patients between 1990 and 2004 was performed. Review of medical records, autopsy reports, and H&E-stained slides of lung tissue was performed. Oil-Red-O and elastic staining of lung tissue were evaluated. All cases were screened for both acute and chronic forms of SCLD. Patients admitted for sickle cell pain crisis ranged in age from 8 months to 65 years. Fifteen out of 21 cases (71.4%) showed significant pulmonary pathology. The most frequent lung findings included pulmonary edema (47.6%), pulmonary thromboembolism (38.1%), fat emboli (33.3%), pulmonary hypertension, grades I-IV (33.3%), and microvascular occlusive thrombi (28.5%). Our study demonstrates higher-than-expected percentages of acute and chronic sickle cell-related lung injury such as fat embolism (33.3%) and pulmonary hypertension (33.3%), with right ventricular hypertrophy (33.3%). Therefore, we propose a simple and high-yield autopsy algorithm of ancillary procedures that should be applied on all known and suspected autopsy cases of sickle cell disease.

Fine-needle aspiration cytologic diagnosis of metastatic melanotic schwannoma: familial case of a mother and daughter with Carney's complex and literature review.

Carney's complex is an autosomal dominant, multisystem tumorous disorder that includes myxomas, spotty skin pigmentation, endocrine tumors, and peripheral nerve tumors. Psammomatous melanotic schwannomas have recently been included as a part of this complex. Here, we describe the first known familial case of a mother and daughter, both presenting with malignant, already metastatic, pigmented schwannomas initially diagnosed as metastatic melanoma by CT guided fine-needle aspiration. Patients with highly pigmented, extra-cutaneous lesions that are clinically and pathologically suspicious for metastatic malignant melanoma, without known primary tumor, should be evaluated for possible Carney's complex. Additional screening of family members should be recommended to exclude the presence of potentially malignant neoplasms, such as psammomatous melanotic schwannomas.

Inhibition of progenitor dendritic cell maturation by plasma from patients with peripartum cardiomyopathy: role in pregnancy-associated heart disease.

Dendritic cells (DCs) play dual roles in innate and adaptive immunity based on their functional maturity, and both innate and adaptive immune responses have been implicated in myocardial tissue remodeling associated with cardiomyopathies. Peripartum cardiomyopathy (PPCM) is a rare disorder which affects women within one month antepartum to five months postpartum. A high occurrence of PPCM in central Haiti (1 in 300 live births) provided the unique opportunity to study the relationship of immune activation and DC maturation to the etiology of this disorder. Plasma samples from two groups (n = 12) of age- and parity-matched Haitian women with or without evidence of PPCM were tested for levels of biomarkers of cardiac tissue remodeling and immune activation. Significantly elevated levels of GM-CSF, endothelin-1, proBNP and CRP and decreased levels of TGF-beta were measured in PPCM subjects relative to controls. Yet despite these findings, in vitro maturation of normal human cord blood derived progenitor dendritic cells (CBDCs) was significantly reduced (p < 0.001) in the presence of plasma from PPCM patients relative to plasma from post-partum control subjects as determined by expression of CD80, CD86, CD83, CCR7, MHC class II and the ability of these matured CBDCs to induce allo-responses in PBMCs. These results represent the first findings linking inhibition of DC maturation to the dysregulation of normal physiologic cardiac tissue remodeling during pregnancy and the pathogenesis of PPCM.

Inhibition of myosin light chain kinase provides prolonged attenuation of radial artery vasospasm.

OBJECTIVE: Current treatments for conduit vessel vasospasm are short-acting and do not inhibit all vasospastic stimuli. This study tests the hypothesis that irreversible inactivation of myosin light chain kinase provides sustained inhibition of arterial vasoconstriction stimulated by a spectrum of vasopressors. METHODS: Canine radial artery segments were soaked for 60 min in control buffer or buffer with wortmannin, an irreversible inhibitor of myosin light chain kinase. The vessels were then thoroughly washed and contractile responses were quantified in response to a spectrum of vasopressors at 2 and 48 h after treatment. After 48 h, selected vessels were examined for morphologic changes and development of apoptosis. RESULTS: Two hours after treatment, wortmannin-soaked vessels contracted significantly less than controls in response to norepinephrine (0.19+/-0.07 g vs. 7.22+/-0.37 g, P<0.001), serotonin (0.92+/-0.35 g vs. 9.64+/-0.67 g, P<0.001), thromboxane-mimetic U46619 (1.25+/-0.17 g vs. 10.99+/-0.50 g, P<0.001), and KCl (1.98+/-0.27 g vs.15.00+/-0.48 g, P<0.001). At 48 h, vasoconstriction remained significantly inhibited in wortmannin-treated vessels compared to control vessels in response to norepinephrine (2.36+/-0.17 vs. 6.95+/-0.47 g, P<0.001), serotonin (4.67+/-0.39 vs. 12.42+/-0.70 g, P<0.001), U46619 (5.42+/-0.34 vs. 9.29+/-0.74 g, P=0.008), and KCl (7.49+/-0.48 vs. 13.32+/-0.60 g, P<0.001). Histology of wortmannin-treated vessels revealed no overt smooth muscle or endothelial cell damage. TUNEL staining revealed a significantly greater proportion of apoptotic smooth muscle and endothelial cells in wortmannin-treated vessels as compared to controls. CONCLUSIONS: Disengaging the smooth muscle contractile apparatus by irreversibly binding myosin light chain kinase with wortmannin significantly attenuates radial artery vasoconstriction up to 48 h after brief treatment. This novel strategy may prevent vasospasm of arterial grafts from all causes for several postoperative days.

Herpes simplex hepatitis in adults: a search for muco-cutaneous clues.

Herpes simplex hepatitis is a treatable cause of acute hepatitis with a high mortality (41% to 79%). We present 4 adult patients who died of herpes simplex hepatitis and review another 70 patients (including pregnant women) from the literature to illustrate that herpes simplex hepatitis was only considered in the differential diagnosis in 26% to 33% of patients even though muco-cutaneous involvement was present in at least 70% of these patients. The presence of muco-cutaneous lesions in a patient with clinical symptoms and biochemical findings of acute hepatitis should raise the suspicion of herpes simplex hepatitis. Prompt treatment with acyclovir can be initiated within hours of admission in an attempt to prevent further hepatocellular damage in this potentially life-threatening infection.

Primary small bowel carcinoid tumor with bilateral breast metastases: report of 2 cases with different clinical presentations.

CONTEXT: Carcinoid tumor metastatic to the breast is uncommon and can closely mimic a mammary carcinoma. The differentiation of metastatic carcinoid tumor from primary breast tumor is important, however, owing to different clinical management and prognosis. OBJECTIVE: The purpose of this study was to describe 2 patients with bilateral metastatic carcinoid tumors to the breast with different clinical manifestations. DESIGN: We examined the radiological, clinical, cytologic, histologic, immunohistochemical, and ultrastructural features of these 2 cases. RESULTS: In case 1, the tumor presented initially as a stellate mass on mammogram and was diagnosed as grade II infiltrating ductal carcinoma. It was only after the discovery of small intestinal, liver, ovarian, and contralateral breast masses, as well as careful morphologic and immunohistochemical evaluations, that the true nature of the tumor was realized. In case 2, the tumor initially presented as a small intestinal tumor with liver metastases and bilateral breast masses. The breast masses were diagnosed accurately as metastatic carcinoid tumor by morphologic and immunohistochemical evaluations. CONCLUSIONS: Metastatic carcinoid tumor to the breast is uncommon, but poses a diagnostic challenge in that morphologically it can closely mimic a primary breast tumor. Careful attention to clinical features and the use of auxiliary immunohistochemical studies can help in arriving at the correct diagnosis.

Fatal West Nile virus encephalitis in a renal transplant recipient.

West Nile virus (WNV), a mosquito-transmitted single-stranded RNA flavivirus, causes human disease of variable severity. We report clinical and pathologic findings of fatal encephalitis from the transmission of WNV from an organ donor to a kidney transplant recipient. The patient developed a febrile illness 18 days after transplantation, which progressed to encephalitis. Postmortem examination demonstrated extensive viral encephalopathic changes. Immunohistochemical studies highlighted WNV antigens within neurons, especially in the cerebellum and brainstem. Flavivirus virions were detected ultrastructurally within the cerebellum, and WNV was isolated from the brain and the brainstem. Thus, this case demonstrates the first death in the first solid organ transplant-associated transmission of WNV. Immunosuppression of the transplant recipient might have been responsible for the fulminant viral effects. The pathologic diagnosis helped guide subsequent epidemiologic and laboratory studies.