Perivascular Cuffing Research Articles

Outbreak of epizootic hemorrhagic disease in captive reindeer (Rangifer tarandus).

In September 2020, an outbreak of epizootic hemorrhagic disease occurred in captive reindeer (Rangifer tarandus) and was associated with neurological signs and mortality. Four reindeer died or were euthanized after acute illness over a 12-day period. Affected reindeer displayed abnormal behavior, neurologic signs, lethargy, and/or lameness. The most consistent gross finding was dark red streaks throughout the adrenal gland cortices (4/4). One animal had acute hemorrhage involving the subcutis and skeletal muscles over the ventrolateral body wall and back, and abomasal serosa. Histologically, the most common lesions were adrenal gland cortical hemorrhage (4/4) with necrosis (3/4) and lymphoplasmacytic meningoencephalitis with gliosis, glial nodules, satellitosis, and nonsuppurative perivascular cuffing (4/4). The brain lesions were most frequent in the gray matter of the cerebrum, hippocampus, and thalamus but also involved the cerebellum and brainstem. Epizootic hemorrhagic disease virus serotype 6 was detected through PCR and sequencing of the spleen in all cases.

Characterization of Immune Infiltrates Associated With Radiation Necrosis in the Setting of Brain Metastases Following Stereotactic Radiosurgery and Immunotherapy: A Retrospective Cohort Analysis.

Radiation necrosis (RN) is caused by vascular damage and brain parenchymal injury resulting in inflammation following radiotherapy (RT) for brain metastases. The impact of immunotherapy (IO) on the immune cellular microenvironment in patients' brain metastases is unknown. The objective of this study was to characterize the inflammatory microenvironment in the setting of RN compared to recurrent metastasis and determine whether IO treatment affects the cellular infiltrates. Adult patients with brain metastases from solid tumors who received both systemic IO and RT prior to resection of intracranial lesions were retrospectively analyzed. The resection either showed biopsy-proven RN or recurrent tumor. A group of patients who developed RN and were not on IO was reviewed as well. A total of 18 patients were categorized into one of three groups: necrosis, IO+RT; tumor, IO+RT; and necrosis, RT. Surgical specimens were stained for immune and inflammatory components and reviewed by a neuro-pathologist who remained blinded during the analysis. The presence or absence of lymphocytes, perivascular cuffs, plasma cells, macrophages, and fibrinoid vascular changes was characterized in a semiquantitative manner. The median age was 61.5 years (range 37-82 years). Seventy-seven percent of primary cancers were melanoma. Patients with RN were more likely to exhibit immune infiltrates compared to patients with recurrent metastasis. Limited analysis showed 100% of patients in "necrosis, IO+RT" had quantifiable cell counts; conversely, 83.3% of patients in "tumor, IO+RT" lacked quantifiable cell counts. Additionally, 83.3% of patients in "necrosis, RT" showed immune cells, including lymphocytes, macrophages, plasma cells, and cuffing. The immune microenvironment of brain metastasis following RT and IO showed higher levels of cell infiltrates in the RN setting versus the recurrent tumor setting. Patients who received prior IO compared to those with no IO had similar immune cell infiltrates adjacent to RN. Lower levels of immune cells in tumor recurrence following IO and RT raise the possibility that an environment lacking primed immune cells may decrease the efficacy of IO.

Suppression of Experimental Autoimmune Encephalomyelitis in Mice by β-Hydroxy β-Methylbutyrate, a Body-Building Supplement in Humans.

Although several immunomodulatory drugs are available for multiple sclerosis (MS), most present significant side effects with long-term use. Therefore, delineation of nontoxic drugs for MS is an important area of research. β-Hydroxy β-methylbutyrate (HMB) is accessible in local GNC stores as a muscle-building supplement in humans. This study underlines the importance of HMB in suppressing clinical symptoms of experimental autoimmune encephalomyelitis (EAE) in mice, an animal model of MS. Dose-dependent study shows that oral HMB at a dose of 1 mg/kg body weight/d or higher significantly suppresses clinical symptoms of EAE in mice. Accordingly, orally administered HMB attenuated perivascular cuffing, preserved the integrity of the blood-brain barrier and blood-spinal cord barrier, inhibited inflammation, maintained the expression of myelin genes, and blocked demyelination in the spinal cord of EAE mice. From the immunomodulatory side, HMB protected regulatory T cells and suppressed Th1 and Th17 biasness. Using peroxisome proliferator-activated receptor (PPAR)α-/- and PPARβ-/- mice, we observed that HMB required PPARβ, but not PPARα, to exhibit immunomodulation and suppress EAE. Interestingly, HMB reduced the production of NO via PPARβ to protect regulatory T cells. These results describe a novel anti-autoimmune property of HMB that may be beneficial in the treatment of MS and other autoimmune disorders.

Impact of P-selectin–PSGL-1 Axis on Platelet-Endothelium-Leukocyte Interactions in Fatal COVID-19

In critically ill patients infected with SARS-CoV-2, early leukocyte recruitment to the respiratory system was found to be orchestrated by leukocyte trafficking molecules accompanied by massive secretion of proinflammatory cytokines and hypercoagulability. Our study aimed to explore the interplay between leukocyte activation and pulmonary endothelium in different disease stages of fatal COVID-19. Our study comprised 10 COVID-19 postmortem lung specimens and 20 control lung samples (5 acute respiratory distress syndrome, 2 viral pneumonia, 3 bacterial pneumonia, and 10 normal), which were stained for antigens representing the different steps of leukocyte migration: E-selectin, P-selectin, PSGL-1, ICAM1, VCAM1, and CD11b. Image analysis software QuPath was used for quantification of positive leukocytes (PSGL-1 and CD11b) and endothelium (E-selectin, P-selectin, ICAM1, VCAM1). Expression of IL-6 and IL-1β was quantified by RT-qPCR. Expression of P-selectin and PSGL-1 was strongly increased in the COVID-19 cohort compared with all control groups (COVID-19:Controls, 17:23, P < .0001; COVID-19:Controls, 2:75, P < .0001, respectively). Importantly, P-selectin was found in endothelial cells and associated with aggregates of activated platelets adherent to the endothelial surface in COVID-19 cases. In addition, PSGL-1 staining disclosed positive perivascular leukocyte cuffs, reflecting capillaritis. Moreover, CD11b showed a strongly increased positivity in COVID-19 compared with all controls (COVID-19:Controls, 2:89; P = .0002), indicating a proinflammatory immune microenvironment. Of note, CD11b exhibited distinct staining patterns at different stages of COVID-19 disease. Only in cases with very short disease course, high levels of IL-1β and IL-6 mRNA were observed in lung tissue. The striking upregulation of PSGL-1 and P-selectin reflects the activation of this receptor–ligand pair in COVID-19, increasing the efficiency of initial leukocyte recruitment, thus promoting tissue damage and immunothrombosis. Our results show that endothelial activation and unbalanced leukocyte migration play a central role in COVID-19 involving the P-selectin–PSGL-1 axis.

Meningioangiomatosis with Skull Erosion

Meningioangiomatosis (MA) is a rare, poorly studied brain hamartomatous lesion, the etiology of which is not fully elucidated. It typically involves the leptomeninges, extending to the underlying cortex, characterized by small vessel proliferation, perivascular cuffing, and scattered calcifications. Given its close proximity to, or direct involvement of, the cerebral cortex, MA lesions typically manifest in younger patients as recurrent episodes of refractory seizures, comprising approximately 0.6% of operated-on intractable epileptic lesions. Due to the absence of characteristic radiological features, MA lesions constitute a significant radiological challenge, making them easy to miss or misinterpret. Although MA lesions are rarely reported with still-unknown etiology, it is prudent to be aware of these lesions for prompt diagnosis and management to avoid morbidity and mortality associated with delayed diagnosis and treatment. We present a case of a young patient with a first-time seizure caused by a right parieto-occipital MA lesion that was successfully excised via an awake craniotomy, achieving 100% seizure control.

Acute toxicity study, haematological, biochemical and histopathological effects of Brassica oleracea var. capitata, Allium porrum and Cucurbita maxima in Rattus norvegicus

Abstract Objectives The use of vegetables in Nigeria as nutraceutical cannot be over emphasized. However many vegetables are associated with toxicity effects at both low and high doses. Methods Hence the study was aimed at investigating acute toxicity, haematological, biochemical and histopathological effects of Allium porrum (leek), Cucurbita maxima (pumpkin) and Brassica oleracea var. capitata (cabbage) in female Rattus norvegicus. The lethal dose50 (LD50) of the three plants were determined. Key findings The LD50 of aqueous extract of cabbage, leek and pumpkin was 6585 mg/kg body weight. Cabbage caused a decrease in packed cell volume, erythrocytes counts, haemoglobin concentration, white blood cells, neutrophils and monocytes counts, increased basophils and eosinophils counts at dose levels of 5.79 mg/kg and 57.93 mg/kg body weight. At dose levels of 5.79–579.3 mg/kg body weight, the extract caused hypoalbuminaemia, hypoglycaemia, hypercholesterolaemia, increased levels of alanine amino transferase (ALT) and alkaline phosphatase. Cabbage also caused necrosis of hepatocytes, glomerular and tubular necrosis, cylinduria and perivascular cuffing in the brain. At dose level of 5.79 mg/kg and above, cabbage may cause abortion during an early stage of pregnancy due to possible loss of endometrial gland. The combined extract of pumpkin and leek caused haematopoiesis, neutropenia, lymphocytosis, eosinophilia, hypoglycaemia, hypocholesterolaemia, elevation of ALT levels, necrosis of hepatocytes and brain tissues, kidney damage and suppression of the development of ovarian follicle. Conclusions Brassica oleracea var. capitata may cause anaemia, immunosuppression, hypoglycaemia, hypercholesterolaemia, abortion, liver and kidney damage. The combined extract of leek and pumpkin may cause haematopoeisis, immunostimulation, hypoglycaemia, hypocholesterolaemia, brain problem and infertility.

Age, and non-age-related cytoarchitectural changes in the brain of some Nigerian cattle

Brain is the most vulnerable organ in the body to the ageing processes which operates at variable levels between organs and species. In this study we examine brains histopathologically for architectural changes in four Nigerian cattle breeds. Brains from 246 cattle (Bunaji=80, Muturu=78, Rahaji=62 and Sokoto Gudali=26), aged 1–≥12years were examined at 8 different neuroanatomical locations. All the cattle used were obtained from Abattoir in Ibadan, Nigeria. They were examined at ante-mortem and those without clinical signs suggestive of neurological disease were sampled. Major changes observed were intracellular accumulation of substances (61.4%), neuronal and or axonal degenerations and loss (51.6%), perivascular cuffing (50.0%), extracellular accumulation of substances (29.7%), hypercellularity (19.1%) and spongy state (0.4%), malacia (0.0%), demyelination (0.0%) in 233 cattle. Intraneuronal vacuolations (35%), lipofuscin accumulation (42%), axonal spheroids (50%), inflammatory changes (50%), and brain sand (22%). Although perivascular cuffing was high, there was low incidence of lymphocytic infiltration in the pineal gland in both sexes. Intracellular accumulation of substances, neuronal and or axonal degenerations and loss, and extracellular accumulation of substances display levels of significant changes with age (p&lt;0.0001). Changes starts at the age of 2 years in life in these breeds of cattle due probably to the adverse stress exerted by the tropical climate. The description of histological findings in the brain of symptomless cattle in the present study provides a useful background for diagnostic bovine neuropathology in the tropics.

Ameliorative effects of piroxicam on perchloric acid-induced thyroid gland hormones disruption in male rats

BackgroundThe incidence of goitre has increased world-wide, with African countries responsible for over 28 % of the cases. The danger of perchloric acid among males working in the factories has been on the increase. Hence mitigating effects of piroxicam on perchloric acid-induced thyroid hormones disruption was studied in male Wister albino rats. MethodsA total of 19 rats (17 males; 2 females) that weighed 145.0 ± 20.5 g were used for the.study. Four rats were used for determination of median lethal dose (LD50) of perchloric acid, whereas 15 rats divided into three groups of five each, were used for induction of thyroid hormones disruption, using 100 mg/kg of perchloric acid for a period of two weeks. Thereafter group II and III rats were treated with 2.5 and 5.0 mg/kg of piroxicam, respectively. Three millilitres of blood were collected from all the rats for determination of thyroid hormones, haematological and biochemical parameters. Brain, liver, spleen, lung, kidney and heart were harvested for allometry and histopathology. ResultsFindings have shown that LD50 of perchloric acid was 4207.5 ± 457.6 mg/kg body weight. Piroxicam significantly decreased (p < 0.05) thyroid stimulating hormone, but increased free triiodothyronine and thyroxine respectively. Alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase and monocytes were increased significantly(p < 0.05). Urea, creatinine, haematocrit, erythrocytes, leucocytes, lymphocytes, neutrophils, platelets and eosinophils counts were decreased significantly (p < 0.05). Allometric parameters were significantly increased (p < 0.05). Histopathology revealed perivascular cuffs of brain, zenker’s necrosis with mononuclear cells infiltration of myocardium, congestion of central vein of liver, mononuclear cells infiltration of the kidney, lymphoid tissue aggregation of white pulp, congestion and thickness of the lungs were observed in the rats administered piroxicam. ConclusionHence piroxicam ameliorates thyroid hormones disruption, induces liver enzymes, modulates humoral immune system, enhances renal function and decreases allometric parameters of brain, lung and liver, as evidenced by histopathological lessons.

Neutralizing IL-8 potentiates immune checkpoint blockade efficacy for glioma

Malignant gliomas are largely refractory to immune checkpoint blockade (ICB) therapy. To explore the underlying immune regulators, we examine the microenvironment in glioma and find that tumor-infiltrating Tcells are mainly confined to the perivascular cuffs and express high levels of CCR5, CXCR3, and programmed cell death protein 1 (PD-1). Combined analysis of Tcell clustering with Tcell receptor (TCR) clone expansion shows that potential tumor-killing Tcells are mainly categorized into pre-exhausted/exhausted and effector CD8+ T subsets, as well as cytotoxic CD4+ T subsets. Notably, a distinct subpopulation of CD4+ Tcells exhibits innate-like features with preferential interleukin-8 (IL-8) expression. With IL-8-humanized mouse strain, we demonstrate that IL-8-producing CD4+ T, myeloid, and tumor cells orchestrate myeloid-derived suppressor cell infiltration and angiogenesis, which results in enhanced tumor growth but reduced ICB efficacy. Antibody-mediated IL-8 blockade or the inhibition of its receptor, CXCR1/2, unleashes anti-PD-1-mediated antitumor immunity. Our findings thus highlight IL-8 as a combinational immunotherapy target for glioma.

Central nervous system syndrome associated with Marek’s disease in Hubbard broilers

Marek’s disease (MD) has a high economic impact in poultry production worldwide. MD consists of several pathologic syndromes of which the most commonly encountered are lymphoproliferative syndromes such as acute MD. Sporadically, MD leads to central nervous system syndromes characterized by non-neoplastic brain pathology. In this case report, an onset of neurological signs on two different broiler farms, housing ‘slow-growing’ Hubbard JA 757 broilers, is described. On the first farm, clinical signs were observed from 42 days of age onwards and on the second farm, respectively from 42 (stable 1) and 30 days (stable 2) of age onwards. The neurological symptoms consisted of acute central nervous system signs, which started with flaccid neck paralysis. Histopathological examination revealed multifocal perivascular cuffing of CD3 positive mononuclear cells in the brain tissues. These findings pointed towards the development of transient paralysis. qPCR analysis confirmed the diagnosis. In broiler flocks, which only have a limited life span, vaccination is not common practice. In flocks of slow-growing breeds, outbreaks of MD might become more important again. Therefore, vaccination of slow-growing broilers against MD seems recommended.

Cadmium and Chlorpyrifos Induced Lipid Peroxidation in Brain, Liver and Kidney of Wistar Rats

The work was designed with 4 groups for 28 days. 1: Control. 2: CdCl2 @ 22.5mg/ kg b.wt / oral. 3: CPF @ 25 mg/ kg b.wt /per oral. 4: CdCl2@22.5 mg + CPF @ 25 mg/ kg b.wt /per oral. Higher mean values of liver, kidney and brain TBARS were observed in G-2, 3 and 4 on 15th and 29th day. Liver section in group 2 revealed mild degenerative changes in group 3; in group 4 mild to moderate peri portal fibrosis. Kidney section in group 2 showed shrunken glomeruli, necrosis; kidney section showed degeneration and necrosis of tubular epithelium with casts in the lumen in group 3 and necrosis with casts in the lumen in group 4. Brain section in group 2 showed mild perivascular cuffing, mild to moderate degeneration of Purkinji cells in group 3 and in group 4 degeneration of Purkinje cells. Effects in G-4 were severe than individual groups due to synergistic action of the combined pollutants than the individual effects.

West Nile Virus-Induced Drop in Egg Production in Commercial Pekin Duck Breeders.

A sudden drop in egg production in commercial poultry flocks can be economically devastating, and rapid identification of the cause often requires a combined effort between the producer, veterinarian, and pathologist. In September 2019, a 35-wk-old commercial Pekin breeder duck flock in Indiana suffered a drop in egg production from 1700 to 1000 eggs daily (41.2% drop). Again, in September 2021, three Pekin breeder duck flocks aged 32, 58, and 62 wk from the same company suffered a similar drop in egg production, with a mild increase in weekly mortality of 1.0% to 2.5%. In 2019 and in 2021, birds from affected flocks were submitted to the Veterinary Diagnostic Laboratory at Michigan State University for postmortem examination. Common gross examination findings included flaccid, shrunken, or atrophied ova (all hens), pododermatitis, airsacculitis, hepatomegaly, splenomegaly, ascites, and pallor of the left ventricle. Histopathologic examination of cerebrum, cerebellum, and brainstem revealed mild lymphocytic perivascular cuffing, vasculitis, and gliosis, suggesting viral encephalitis. In the heart, there was mild multifocal cardiomyocyte necrosis, mineralization, and infiltration by lymphocytes and macrophages. PCR for Newcastle disease virus, avian influenza virus, eastern equine encephalitis virus, and West Nile virus (WNV) was performed. Brain and heart samples were positive for WNV by PCR, and WNV antigen was detected in the cerebellum by immunohistochemistry. This is the first report to associate WNV infection with a drop in egg production in waterfowl, which are known to be important reservoir species for WNV and, as such, are generally asymptomatic.

Abstract B032: Immune landscape of resected brain metastases in patients treated with and without immune checkpoint blockade immunotherapy

Abstract Background: The brain metastatic niche has been historically difficult to study and thus poorly understood. Although brain metastases portend high morbidity and mortality, increasing evidence has shown that immune checkpoint blockade (ICB) can confer long-lasting responses in patients. How ICB remodels the brain tumor microenvironment is still relatively unknown. Here, we examine the immune microenvironment of resected brain metastases in a cohort of 19 patients pre-operatively treated with and without ICB using single-cell methods. Methods: Tumor tissue was obtained from patients who underwent surgical resection of brain metastases at our institution, and single-cell RNA sequencing (scRNAseq) and multiplex immunofluorescence (mIF) analyses were performed, including unsupervised clustering and multivariate regression. Results: A total of 8 patients with pre-operative exposure and 11 patients without pre-operative exposure to ICB were included. Represented histologies included melanoma, breast, lung, and endometrial cancers. Basic demographic and clinical characteristics, including age, sex, body mass index, performance status, stage at initial diagnosis, and time from initial diagnosis to development of brain metastases were not significantly different between the two groups. mIF revealed an immune exclusion phenotype in ICB naïve samples compared to ICB-treated samples, manifested by the lower density and percentage of lymphoid infiltrate and presence of immune perivascular cuffing. T cells in the ICB-treated group had higher expression of both effector and exhaustion markers (IFNG, GZMH, PDCD1, HAVCR2, TOX, NR4A2, NR4A1); while myeloid cells exhibited increased interferon-stimulated gene expression (CXCL9, CXCL10, STAT1, GBP1, GBP4, GBP5, MHC-II genes). One particular cluster of CD8+ T cells, the TCF and CD226-expressing progenitor population, correlated with overall survival. Furthermore, ICB-treated samples showed decreased CD14+ CD206+ perivascular macrophages, suggesting that these macrophages play a role in restraining immune cell extravasation and tumor infiltration. Conclusion: This work contributes to the growing understanding of the brain metastatic niche and the impact of ICB on this unique microenvironment. While it is not surprising that we found increased T cell numbers and activation in ICB-treated samples, we also found increased evidence of TIL exhaustion. This may be a result of selection bias, as patients who undergo resection after ICB treatment typically do so due to poor response and intracranial progression, or from chronic antigen stimulation from checkpoint inhibition. Interestingly, our studies suggest that the myeloid populations, particularly the perivascular macrophages, are an important mediator of the brain tumor microenvironment. Further functional studies are needed to investigate the role of these perivascular macrophages and elucidate the cross-talk between these cells, infiltrating lymphocytes, and the brain vasculature. Citation Format: Eileen F. Shiuan, Lu Sun, Jeremy Reynoso, Shanpeng Li, Gang Li, Jiyoon Kim, Won Kim, Robert Prins. Immune landscape of resected brain metastases in patients treated with and without immune checkpoint blockade immunotherapy [abstract]. In: Proceedings of the AACR Special Conference: Cancer Metastasis; 2022 Nov 14-17; Portland, OR. Philadelphia (PA): AACR; Cancer Res 2022;83(2 Suppl_2):Abstract nr B032.

Golgi localization of SARS-CoV-2 spike protein and interaction with furin in cerebral COVID-19 microangiopathy: a clue to the central nervous system involvement?

In a neuropathological series of 20 COVID-19 cases, we analyzed six cases (three biopsies and three autopsies) with multiple foci predominantly affecting the white matter as shown by MRI. The cases presented with microhemorrhages evocative of small artery diseases. This COVID-19 associated cerebral microangiopathy (CCM) was characterized by perivascular changes: arterioles were surrounded by vacuolized tissue, clustered macrophages, large axonal swellings and a crown arrangement of aquaporin-4 immunoreactivity. There was evidence of blood-brain-barrier leakage. Fibrinoid necrosis, vascular occlusion, perivascular cuffing and demyelination were absent. While no viral particle or viral RNA was found in the brain, the SARS-CoV-2 spike protein was detected in the Golgi apparatus of brain endothelial cells where it closely associated with furin, a host protease known to play a key role in virus replication. Endothelial cells in culture were not permissive to SARS-CoV-2 replication. The distribution of the spike protein in brain endothelial cells differed from that observed in pneumocytes. In the latter, the diffuse cytoplasmic labeling suggested a complete replication cycle with viral release, notably through the lysosomal pathway. In contrast, in cerebral endothelial cells the excretion cycle was blocked in the Golgi apparatus. Interruption of the excretion cycle could explain the difficulty of SARS-CoV-2 to infect endothelial cells in vitro and to produce viral RNA in the brain. Specific metabolism of the virus in brain endothelial cells could weaken the cell walls and eventually lead to the characteristic lesions of COVID-19 associated cerebral microangiopathy. Furin as a modulator of vascular permeability could provide some clues for the control of late effects of microangiopathy.

Mouse Adapted SARS-CoV-2 (MA10) Viral Infection Induces Neuroinflammation in Standard Laboratory Mice.

Increasing evidence suggests that severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection impacts neurological function both acutely and chronically, even in the absence of pronounced respiratory distress. Developing clinically relevant laboratory mouse models of the neuropathogenesis of SARS-CoV-2 infection is an important step toward elucidating the underlying mechanisms of SARS-CoV-2-induced neurological dysfunction. Although various transgenic models and viral delivery methods have been used to study the infection potential of SARS-CoV-2 in mice, the use of commonly available laboratory mice would facilitate the study of SARS-CoV-2 neuropathology. Herein we show neuroinflammatory profiles of immunologically intact mice, C57BL/6J and BALB/c, as well as immunodeficient (Rag2-/-) mice, to a mouse-adapted strain of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2 (MA10)). Our findings indicate that brain IL-6 levels are significantly higher in BALB/c male mice infected with SARS-CoV-2 MA10. Additionally, blood-brain barrier integrity, as measured by the vascular tight junction protein claudin-5, was reduced by SARS-CoV-2 MA10 infection in all three strains. Brain glial fibrillary acidic protein (GFAP) mRNA was also elevated in male C57BL/6J infected mice compared with the mock group. Lastly, immune-vascular effects of SARS-CoV-2 (MA10), as measured by H&E scores, demonstrate an increase in perivascular lymphocyte cuffing (PLC) at 30 days post-infection among infected female BALB/c mice with a significant increase in PLC over time only in SARS-CoV-2 MA10) infected mice. Our study is the first to demonstrate that SARS-CoV-2 (MA10) infection induces neuroinflammation in laboratory mice and could be used as a novel model to study SARS-CoV-2-mediated cerebrovascular pathology.

Goats Naturally Infected with the Spanish Goat Encephalitis Virus (SGEV): Pathological Features and An Outbreak

In autumn 2011, a disease outbreak caused by Spanish goat encephalitis virus (SGEV) was reported in a herd of goats from Asturias (north-western Spain), expanding the known geographic distribution of tick-borne encephalitis in Europe. The virus was classified as a new subtype (subspecies) within the Louping-ill virus species of the mammalian tick-borne flavivirus group. The aims of the present study were to describe the pathology in goats naturally infected with SGEV, as well as discuss the pathogenesis of the disease in that outbreak. A total of 22/85 (25.88%) goats (20 adults and 2 kids) died between October 2011 and June 2012, showing neurological clinical signs. Over three years, the mortality rate in the herd reached 100%. Neuropathological lesions caused by SGEV were severe and widespread throughout the central nervous system but were more severe and numerous in the proximal cervical spinal cord, medulla oblongata, pons and cerebellar cortex. They consisted of neuron necrosis, neuronophagia, mononuclear inflammatory cell perivascular cuffs (lymphocytes, plasma cells and macrophages) and gliosis. The distribution of viral antigens was restricted to the cytoplasm of neurons in several brain areas but not associated with inflammatory foci nor inflammatory cells. SGEV should be considered a significant pathogen of goats that results in severe neurological clinical disease and high mortality.

A novel mouse model of SARS‐CoV‐2 induced neuroinflammation

AbstractBackgroundSevere acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) infection may impact neurological function acutely or chronically, even in the absence of severe respiratory illness. Developing clinically relevant laboratory models to understand the neuropathogenesis of SARS‐CoV‐2 infection is an important step towards unravelling this neurologic consequence. We hypothesize that mouse adapted SARS‐CoV‐2 viral infection will induce neuroinflammation in immuno‐competent C57BL/6J (10 weeks old male) as well as immunodeficient RAG2−/‐ (10 weeks old male) and BALB/c (1 year old female) mice.MethodAll three mouse strains were inoculated intranasally with a dose of 1×103 PFU/mouse (50 µL) of either mock or the mouse‐adapted (MA)10 strain of SARS‐CoV‐2 (BEI resource, NR‐55329). Mice were euthanized on day 2, 3, 7, 15 or 30 post infection and brain samples processed for qRT‐PCR, immunofluorescence, and H&amp;E analysis.ResultSARS‐CoV‐2 MA10 resulted in a significantly higher (p &lt; 0.05) mRNA expression for chemokine ligand 2 (CCL2) and lower (p &lt; 0.05) mRNA expression for the blood‐brain barrier component Claudin‐5 in RAG2−/‐ and WT mice when compared to mock infection. Also, SARS‐CoV‐2 MA10 infection increased microglial expression in 1 year old female BALB/c mice after 2 days of infection, compared to mock infected group. At 30 days post infection, MA10 infected BALB/c mice had a higher perivascular lymphocyte cuffing in the brain.ConclusionThis study demonstrates that the mouse‐adapted MA10 strain of SARS‐CoV‐2 can induce a neuroinflammatory state in the brain and more so in immunodeficient and aging mouse models. These mouse models will enable the investigation of the long‐term neurological effects of SARS‐CoV‐2 infection.

Experimental infection of aquatic bird bornavirus 1 in domestic chickens

Aquatic bird bornavirus 1 (ABBV-1), classified in the Orthobornavirus genus, is a neurotropic virus that infects wild waterfowl causing persistent infection of the nervous system. Given the conspicuous presence of wild waterfowl in urban areas and farmlands, spillover of this virus into domesticated poultry species is a concern. The goal of this study was to test the ability of ABBV-1 to infect and cause disease in chickens. Two day-old, White Leghorn chickens (n, 176) were inoculated with ABBV-1 through the oral, intramuscular, or intracranial routes, and sampled at 1, 4, 8, and 12-weeks post infection (wpi) to assess virus replication and lesion development. Chickens became infected only through the intracranial and intramuscular routes, developing earliest infection in the brain by 1 wpi (intracranial group), and spinal cord by 8 wpi (intramuscular group). Except for the kidney of one bird in the intracranial group, no other tissues (including choanal and cloacal swabs) tested positive for the virus. Therefore, while the virus could reach the central nervous tissue (CNS) from the muscle in approximately 20% of birds (centripetal spread), it inefficiently reached peripheral sites after replication in the CNS (centrifugal spread). Inflammation in the CNS was observed in the intracranial and intramuscular groups starting at 8 and 12 wpi, respectively, and consisted of mononuclear perivascular cuffing. This is the first study to document the susceptibility of chickens to ABBV-1 infection, and indicates that this species can become infected with ABBV-1, although less extensively than what is observed in waterfowl. This suggests that ABBV-1 replication is partially restricted in gallinaceous birds.

Magnetic resonance imaging and pathological characteristics of Cladophialophora encephalitis in a young dog

AbstractA 1‐year‐old dog was presented for persistent neck pain and circling. Magnetic resonance imaging revealed a large, space‐occupying, intra‐axial mass with extensive surrounding vasogenic oedema affecting the left thalamus and hippocampus. Postmortem histopathology of the brain lesion identified fungal hyphae with significant local brain reaction. Fungal sequencing confirmed Cladophialophora bantiana. Magnetic resonance imaging findings can look similar to other inflammatory processes or even neoplasia. While histopathology of the lesions may not always identify fungal hyphae, it will often confirm necrosis, pyogranulomatous inflammation and perivascular cuffing with lymphocytes. Cerebral phaeohyphomycosis should be included in the differential diagnosis list in a young dog with intracranial neurologic deficits.

Subtle vascular and astrocytic changes in the brain of coronavirus disease 2019 (COVID-19) patients.

Background and purposeIn the central nervous system, a multitude of changes have been described associated with severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) infection, such as microglial activation, perivascular lymphocyte cuffing, hypoxic‐ischaemic changes, microthrombosis, infarcts or haemorrhages. It was sought here to assess the vascular basement membranes (vBMs) and surrounding perivascular astrocytes for any morphological changes in acute respiratory syndrome (coronavirus disease 2019, COVID‐19) patients.MethodsThe light microscopy morphology of the vBMs and perivascular astrocytes from brains of 14 patients with confirmed SARS‐CoV‐2 infection was analysed and compared to four control patients utilizing fluorescent immunohistochemistry for collagen IV and astrocytes (GFAP), endothelia (CD31), tight junction 1 (TJ1) adhesion protein, as well as the aquaporin 4 (AQP4) water channel. On 2D and 3D deconvoluted images from the cortex and white matter, vessel densities, diameters, degree of gliosis, collagen IV/GFAP and GFAP/AQP4 colocalizations were calculated, as well as the fractal dimension of astrocytes and vBMs viewed in tangential planes.ResultsFractal dimension analysis of the GFAP‐stained astrocytes revealed lower branching complexities and decreased GFAP/collagen IV colocalization for COVID‐19 patients. Interestingly, vBMs showed significantly increased irregularities (fractal dimension values) compared to controls. Vessel diameters were increased in COVID‐19 cases, especially for the white matter, TJ1 protein decreased its colocalization with the endothelia, and AQP4 reduced its co‐expression in astrocytes.ConclusionsOur data on the irregularity of the basement membranes, loss of endothelial tight junction, reduction of the astrocyte end‐feet and decrease of AQP4 suggest subtle morphological changes of the blood–brain barrier in COVID‐19 brains that could be linked with indirect inflammatory signalling or hypoxia/hypercapnia.