Pathogenesis of Experimental Infection of Nile Tilapia (Oreochromis niloticus) with Nucleospora Braziliensis Pathology and Proteomic of Microsporidia.

The recent discovery of disease caused by Nucleospora braziliensis in Nile tilapia (Oreochromis niloticus) is important as it has highlighted the high prevalence of infection and associated mortality in cultured fish. Thus, this study conducted an experimental infection of this microsporidium to evaluate pathological alterations and conduct proteomic analysis. For pathological observation, samples of brain, eyes, gall bladder, gut, heart, kidney, liver, muscle, skin, spleen, and stomach tissue, were collected, and liquid chromatography-mass spectrometry (LC-MS/MS) was performed for proteomic analysis. The most prevalent lesions were brownish color of the liver, gill filament fusion, gut ischemia, hemorrhage of the lips and fins, hepatomegaly, spleen atrophy, splenomegaly, and stomach congestion. The most common microscopic lesions were degeneration, hemorrhage, and inflammation in the brain, gills, gut, kidney, liver, muscle, spleen, and stomach. The digested peptides were identified by LC-MS/MS and the intersection of each group showed that in the spleen there were 121 exclusive proteins in the infected sample and 252 in the control, while in the kidney, 129 proteins were identified in the infected specimen compared to 83 in the control. In conclusion, this study demonstrates the proteome profile of O. niloticus kidney and spleen tissue in response to infection with N. braziliensis.

An integrated analysis of the structural changes and gene expression of spleen in human visceral leishmaniasis with and without HIV coinfection.

The spleen plays a pivotal role in the pathogenesis of visceral leishmaniasis. In severe forms of the disease, the spleen undergoes changes that can compromise its function in surveilling blood-circulating pathogens. In this study, we present an integrated analysis of the structural and gene expression alterations in the spleens of three patients with relapsing visceral leishmaniasis, two of whom were coinfected with HIV. Our findings reveal that the IL6 signaling pathway plays a significant role in the disorganization of the white pulp, while BCL10 and ICOSLG are associated with spleen organization. Patients coinfected with HIV and visceral leishmaniasis exhibited lower splenic CD4+ cell density and reduced expression of genes such as IL15. These effects may contribute to a compromised immune response against L. infantum in coinfected individuals, further impacting the structural organization of the spleen.

Dynamic changes in B cell subpopulations in response to triple-negative breast cancer development.

Despite presenting a worse prognosis and being associated with highly aggressive tumors, triple-negative breast cancer (TNBC) is characterized by the higher frequency of tumor-infiltrating lymphocytes, which have been implicated in better overall survival and response to therapy. Though recent studies have reported the capacity of B lymphocytes to recognize overly-expressed normal proteins, and tumor-associated antigens, how tumor development potentially modifies B cell response is yet to be elucidated. Our findings reveal distinct effects of 4T1 and E0771 murine tumor development on B cells in secondary lymphoid organs. Notably, we observe a significant expansion of total B cells and plasma cells in the tumor-draining lymph nodes (tDLNs) as early as 7 days after tumor challenge in both murine models, whereas changes in the spleen are less pronounced. Surprisingly, within the tumor microenvironment (TME) of both models, we detect distinct B cell subpopulations, but tumor development does not appear to cause major alterations in their frequency over time. Furthermore, our investigation into B cell regulatory phenotypes highlights that the B10 Breg phenotype remains unaffected in the evaluated tissues. Most importantly, we identified an increase in CD19 + LAG-3 + cells in tDLNs of both murine models. Interestingly, although CD19 + LAG-3 + cells represent a minor subset of total B cells (< 3%) in all evaluated tissues, most of these cells exhibit elevated expression of IgD, suggesting that LAG-3 may serve as an activation marker for B cells. Corroborating with these findings, we detected distinct cell cycle and proliferation genes alongside LAG-3 analyzing scRNA-Seq data from a cohort of TNBC patients. More importantly, our study suggests that the presence of LAG-3 B cells in breast tumors could be associated with a good prognosis, as patients with higher levels of LAG-3 B cell transcripts had a longer progression-free interval (PFI). This novel insight could pave the way for targeted therapies that harness the unique properties of LAG-3 + B cells, potentially offering new avenues for improving patient outcomes in TNBC. Further research is warranted to unravel the mechanistic pathways of these cells and to validate their prognostic value in larger, diverse patient cohorts.

Transmissibility of Mycobacterium pinnipedii in a murine model.

The causative agent of tuberculosis in pinnipeds is Mycobacterium pinnipedii, a member of the Mycobacterium tuberculosis complex (MTC). The natural hosts are pinnipeds; however, other non-marine mammals, including humans, can also be infected. The transmissibility of a pathogen is related to its virulence. The transmissibility of a M. pinnipedii strain (i.e., 1856) was investigated in a murine model and compared with that of two Mycobacterium bovis strains (i.e., 534 and 04-303) with different reported virulence. Non-inoculated mice (sentinels) were co-housed with intratracheally inoculated mice. Detailed inspection of mice to search for visible tuberculosis lesions in the lungs and spleen was performed, and bacillus viability at 30, 60, and 90 days post-inoculation (dpi) was assayed. A transmissibility of 100% was recorded at 30 dpi in sentinel mice co-housed with the inoculated mice from the M. pinnipedii and M. bovis 04-303 groups, as evidenced by the recovery of viable M. pinnipedii and M. bovis from the lungs of sentinel mice. Mice inoculated with M. pinnipedii (1856) and M. bovis (534) survived until euthanized, whereas five of the M. bovis 04-303-inoculated mice died at 17 dpi. This study constitutes the first report of the transmissibility of a M. pinnipedii strain in mice and confirms the utility of this experimental model to study virulence features such as the transmission of poorly characterized MTC species.

Participation of the spleen in the neuroinflammation after pilocarpine-induced status epilepticus: implications for epileptogenesis and epilepsy.

Epilepsy, a chronic neurological disorder characterized by recurrent seizures, affects millions of individuals worldwide. Despite extensive research, the underlying mechanisms leading to epileptogenesis, the process by which a normal brain develops epilepsy, remain elusive. We, here, explored the immune system and spleen responses triggered by pilocarpine-induced status epilepticus (SE) focusing on their role in the epileptogenesis that follows SE. Initial examination of spleen histopathology revealed transient disorganization of white pulp, in animals subjected to SE. This disorganization, attributed to immune activation, peaked at 1-day post-SE (1DPSE) but returned to control levels at 3DPSE. Alterations in peripheral blood lymphocyte populations, demonstrated a decrease following SE, accompanied by a reduction in CD3+ T-lymphocytes. Further investigations uncovered an increased abundance of T-lymphocytes in the piriform cortex and choroid plexus at 3DPSE, suggesting a specific mobilization toward the Central Nervous System. Notably, splenectomy mitigated brain reactive astrogliosis, neuroinflammation, and macrophage infiltration post-SE, particularly in the hippocampus and piriform cortex. Additionally, splenectomized animals exhibited reduced lymphatic follicle size in the deep cervical lymph nodes. Most significantly, splenectomy correlated with improved neuronal survival, substantiated by decreased neuronal loss and reduced degenerating neurons in the piriform cortex and hippocampal CA2-3 post-SE. Overall, these findings underscore the pivotal role of the spleen in orchestrating immune responses and neuroinflammation following pilocarpine-induced SE, implicating the peripheral immune system as a potential therapeutic target for mitigating neuronal degeneration in epilepsy.

Phospholipase D regulates ferroptosis signal transduction in mouse spleen hypoxia response.

High-altitude hypoxia exposure can lead to phospholipase D-mediated lipid metabolism disorder in spleen tissues and induce ferroptosis. Nonetheless, the key genes underlying hypoxia-induced splenic phospholipase D and the ferroptosis pathway remain unclear. This study aimed to establish a hypoxia animal model. Combined transcriptomic and proteomic analyses showed that 95 predicted target genes (proteins) were significantly differentially expressed under hypoxic conditions. Key genes in phospholipase D and ferroptosis pathways under hypoxic exposure were identified by combining Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis techniques. Gene set enrichment analysis (GSEA) showed that the differential gene sets of the phospholipase D and ferroptosis signaling pathways were upregulated in the high-altitude hypoxia group. The genes in the phospholipase D signalling pathway were verified, and the expression levels of KIT and DGKG were upregulated in spleen tissues under hypoxic exposure. Subsequently, the mRNA and protein expression levels of genes from the exogenous pathway such as TFRC, SLC40A1, SLC7A11, TRP53, and FTH1 and those from the endogenous pathway such as GPX4, HMOX1, and ALOX15 differentials in the ferroptosis signalling pathway were verified, and the results indicated significant differential expression. In summary, exposure to high-altitude hypoxia mediated phospholipid metabolism disturbance through the phospholipase D signalling pathway and further induced ferroptosis, leading to splenic injury.

Changes in splenic tissue and immune response profile of Schistosoma mansoni infected mice submitted to chronic ethanol intake.

In Schistosoma mansoni infection, the spleen is one of the organs affected, causing its enlargement (splenomegaly). Intake of ethanol through alcoholic beverages can cause spleen atrophy and interfere with immune activity. To gain knowledge of this association on the spleen and on the immune response profile, male mice were used as an experimental model. These animals were divided into four groups: C. control; EC. uninfected/ethanol gavage; I. infected; and IE. infected/ethanol gavage. Groups I and IE were infected with about 100 cercariae (BH strain) of S. mansoni and in the fifth week of infection, gavage 200 µL/day/animal of 18 % ethanol was started for 28 consecutive days. At the end of the gavage (9th week of infection) all animals were euthanized. The spleen was removed and longitudinally divided in two parts. After histological processing, the sections were stained with H&E and Gomori's Reticulin for histopathological and stereological analyses, white pulp morphometry and quantification of megakaryocytes. The other fragment was macerated (in laminar flow) and the cell suspension, after adjusting the concentration (2 × 106), was plated to obtain cytokines produced by spleen cells that were measured by flow cytometry (Citometric Bead Array). Histopathological and quantitative analyzes in the spleen of the IE group showed an increase in the number of trabeculae and megakaryocytes, a decrease in reticular fibers, as well as important organizational changes in the white pulp and red pulp. Due to the decrease in the levels of cytokines measured and the result of the calculation of the ratio between the IFN-y and IL-10 cytokines (p = 0.0079) of the infected groups, we suggest that ethanol decreased the inflammatory and anti-inflammatory response generated by the infection (group IE, the production of cytokines was significantly decreased (p < 0.01). These changes demonstrate that ethanol ingestion interferes with some parameters of experimental S. mansoni infection, such as changes in splenic tissue and in the pattern of cytokine production.

The Role of MMP-9 in Regulating Degradation of the Splenic Microvascular Basement Membrane Induced by High Altitude Hypoxia / Rol de la MMP-9 en la Regulación de la Degradación de la Membrana Basal Microvascular Esplénica Inducida por Hipoxia de Altura

SUMMARY: To investigate changes of MMP-9 in the rat spleen and hypoxia-induced microvascular basement membrane under high altitude hypoxia. Thirty male specific pathogen-free Sprague Dawley rats were randomly divided into control and hypoxia groups, with 15 rats in each group. The rats in the control group were placed in Dingxi City, Gansu Province (2080 m above sea level) for 30 days. Rats in the hypoxia group were raised in a hypoxic environment in Maduo County, Qinghai Province (4300 m above sea level), for 30 days to establish a hypoxic rat model. Routine blood tests, MMP-9 mRNA, MMP-9 protein, and the spleen microvascular basement membrane were detected. (1) Compared with the control group, the red blood cell count, hemoglobin, and hematocrit levels of the rats in the hypoxia group were all increased; thus, a hypoxia model was successfully established. (2) Compared with the control group, the expression of MMP-9 mRNA and protein was significantly higher in the spleen of rats in the hypoxic group, and the difference was statistically significant (P <0.05). (3) Compared with the control group, the blood vessel basement membrane in the spleen of the hypoxia group was degraded. Under natural low air pressure and high altitude conditions, the expression of MMP-9 in rat spleen tissue increases and participates in the degradation of the microvascular basement membrane.

El objetivo de este trabajo fue investigar los cambios de la MMP-9 en el bazo de la rata y la membrana basal microvascular inducida bajo hipoxia a gran altura. Treinta ratas macho Sprague Dawley, libres de patógenos específicos, se dividieron aleatoriamente en dos grupos de 15 ratas cada uno, un grupo control y un grupo hipoxia. Durante 30 días las ratas del grupo control estuvieron en la ciudad de Dingxi, provincia de Gansu (2080 m sobre el nivel del mar). Las ratas del grupo de hipoxia se criaron en un entorno hipóxico en el condado de Maduo, provincia de Qinghai (4300 m sobre el nivel del mar), durante 30 días para establecer un modelo de rata hipóxica. Se realizaron análisis de sangre de rutina, ARNm de MMP-9, proteína MMP-9 y de la membrana basal microvascular del bazo. En comparación con el grupo control, el recuento de glóbulos rojos, la hemoglobina y los niveles de hematocrito de las ratas del grupo de hipoxia aumentaron; por lo tanto, se estableció con éxito un modelo de hipoxia. En comparación con el grupo control, la expresión de ARNm y proteína de MMP-9 fue significativamente mayor en el bazo de las ratas del grupo hipóxico, siendo la diferencia estadísticamente significativa (P <0,05). En comparación con el grupo control, la membrana basal de los vasos sanguíneos estaba degradada en el bazo del grupo hipoxia. En condiciones naturales de baja presión atmosférica y gran altitud, la expresión de MMP-9 en el tejido del bazo de la rata aumenta y participa en la degradación de la membrana basal microvascular.

Oropouche virus infection induces ROS production and oxidative stress in liver and spleen of mice.

Oropouche virus (OROV) is the aetiological agent of Oropouche fever, the symptoms of which are common to most arboviruses, such as fever, headache, malaise, nausea and vomiting. More than half a million people have been infected with OROV since its isolation in 1955. Although Oropouche fever is classified as a neglected and emerging disease, to date, there are no antiviral drugs or vaccines available against the infection and little is known about its pathogenicity. Therefore, it is essential to elucidate the possible mechanisms involved in its pathogenesis. Since oxidative stress plays a pivotal role in the progression of various viral diseases, in this study, redox homeostasis in the target organs of OROV infection was evaluated using an animal model. Infected BALB/c mice exhibited reduced weight gain, splenomegaly, leukopenia, thrombocytopenia, anaemia, development of anti-OROV neutralizing antibodies, increased liver transaminases, and serum levels of pro-inflammatory cytokines tumour necrosis factor (TNF-α) and interferon-γ (IFN-γ). The OROV genome and infectious particles were detected in the liver and spleen of infected animals, with liver inflammation and an increase in the number and total area of lymphoid nodules in the spleen. In relation to redox homeostasis in the liver and spleen, infection led to an increase in reactive oxygen species (ROS) levels, increased oxidative stress biomarkers malondialdehyde (MDA) and carbonyl protein, and decreased activity of the antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT). Taken together, these results help elucidate some important aspects of OROV infection that may contribute to the pathogenesis of Oropouche.

Aspectos radiológicos do baço intrapancreático / Radiological aspects of intra-pancreatic spleen

Baço ­ acessório localizado dentro do parênquima pancreático ­ é uma anomalia congênita do tecido esplênico, com características morfológicas e histológicas semelhantes ao baço normal apresentado, geralmente, na cauda do pâncreas. O baço acessório intrapancreático (BAI) trata-se, sobretudo, de uma lesão benigna, usualmente assintomática e encontrada incidentalmente em estudos de imagem, mas que suscitam frequentemente uma preocupação de malignidade e podem ser radiologicamente indistinguíveis de tumores neuroendócrinos, tumores pancreáticos e adenocarcinomas. O presente estudo visa, portanto, relatar um caso de baço acessório intrapancreático através da tomografia computadorizada (TC) e ressonância magnética (RM), além de correlacionar os achados radiográficos do relato de caso com outros métodos radiológicos encontrados na revisão de literatura. As informações contidas foram obtidas por meio de revisão do prontuário, entrevista com o paciente, registro fotográfico dos métodos diagnósticos em geral e dados laboratoriais, aos quais o paciente foi submetido. Nesse contexto, o relato de caso é de um homem com história prévia de carcinoma de células renais que, após realização de nefrectomia total à esquerda e de linfonodos retroperitoneais, constatou no seguimento de seus exames de controle pós-operatório uma imagem nodular na cauda pancreática sugestiva de metástase, mas que, através do estudo tomográfico e de RM, foi possível realizar o correto diagnóstico, tratando-se apenas de uma afecção benigna assintomática e de intervenção conservadora descrita como BAI (AU).

The spleen, an accessory organ located within the pancreatic parenchyma, is a congenital anomaly of the splenic tissue with morphological and histological characteristics resembling a normal spleen, usually in the tail of the pancreas. The intra-pancreatic accessory spleen (IPAS) is mainly a benign lesion, being usually asymptomatic and found on imaging studies on an incidental basis, but which often raises concern about malignancy and may be radiographically indistinguishable from neuroendocrine tumors, pancreatic tumors, and adenocarcinomas. Therefore, the present study aims to report a case of IPAS using computed tomography (CT) and magnetic resonance (MR) imaging, in addition to correlating the radiographic findings of the case report with other radiological methods in the literature review. Information was obtained by reviewing medical records, conducting interviews with the patient, and using diagnostic photographs and laboratory data. In this context, the case report is of a male patient with previous history of renal cell carcinoma who had undergone total left nephrectomy and resection of retroperitoneal lymph nodes. Post-operative followed-up exams showed a nodular image in the pancreatic tail suggestive of metastasis, but whose correct diagnosis was possible by CT and MR studies as only an asymptomatic benign affection was shown, meaning that only a conservative intervention was necessary (AU).

Study of the upper pole after subtotal splenectomy in rats.

PURPOSE: To evaluate macro/microscopic viability of the upper pole (UP) in rats after 80 days of subtotal splenectomy preserving the upper pole (SSPUP). METHODS: Twenty-five male Wistar rats were submitted to SSPUP. After 80 days, the rats were euthanized, and the remaining UP was evaluated macroscopically regarding appearance, color, consistency, length, width, thickness, and presence of fibrosis/necrosis; and microscopically regarding presence of red and white pulp, fibrosis/necrosis. RESULTS: Two rats died during surgery and were removed from the statistical analysis. There was statistically significant increase in length and width between the pre and postoperative in the experimental group, with no significant difference in thickness. In the manipulation group, the macroscopic appearance of the spleen was normal in pre and postoperative, with viability preserved. In the experimental group, two UP of the spleen were not found during the second surgery. Macroscopically, it was observed absence of fibrosis and necrosis in all cases. Microscopically, the white and red pulp were intact in both groups. Two spleens of rats in the manipulation group presented areas with fibrosis and necrosis focus, which were not enough to be considered inviable. CONCLUSIONS: The UP of the spleen remained viable in 91.3% of the cases.

Random Skin Biopsy Is a Useful Procedure in the Evaluation of Hemophagocytic Lymphohistiocytosis: A Case Report and Review of Literature.

ABSTRACT: Hemophagocytic lymphohistiocytosis (HLH) is a rare, life-threatening syndrome, characterized by aberrant activation of T lymphocytes and macrophages leading to hypercytokinemia. HLH can be familial or a result of various secondary etiologies. We present a case of a 46-year-old woman with a past medical history of multiple sclerosis on rituximab who presented as a transfer from an outside hospital with numerous clinical abnormalities including recurrent episodes of fever of unknown origin for 3 weeks, persistent leukocytosis, hypertriglyceridemia, and steatohepatitis. Given the uncertain nature of her illness, she underwent a random skin biopsy from the abdominal region to exclude hematolymphoid malignancy. Histopathology revealed a brisk histiocytic rich dermal infiltrate accompanied by perivascular lymphocytic infiltrate. The histiocytes were enlarged and positive for muraminadase and CD68 stains exhibiting hemophagocytosis focally. As per the HLH-2004 protocol, our patient met the diagnostic criteria of HLH. Concurrent bone marrow biopsy revealed similar rare hemophagocytosis. Cytogenetics and molecular studies were negative, supporting secondary HLH.

Pathological aspects of cutaneous mast cell tumors with metastases in 49 dogs.

Cutaneous mast cell tumor (MCT) is one of the most frequent cutaneous neoplasms of dogs and may vary from well-differentiated to aggressive tumors with metastasis. The authors retrospectively described the gross and histologic aspects of metastatic MCT in 49 dogs. Primary MCT was most commonly identified in the inguinal region (14/35; 40%), and at necropsy multiple, cutaneous nodules were frequently reported (23/49; 47%). All primary MCT were classified as high-grade neoplasms, and metastases involved the lymph nodes (47/49; 96%), spleen (33/49; 67%), liver (29/49; 59%), bone marrow (20/49; 41%), kidneys (16/49; 33%), and heart (14/49; 29%), while the lungs were less commonly affected (9/49; 18%). The main gross findings included lymphadenomegaly in 47 cases; splenomegaly in 28 cases, with splenic nodules in 13 dogs; hepatomegaly in 28 cases, with white pinpoint foci in 9 cases; nodules on the capsular surface of the kidneys in 9 dogs; and epicardial nodules in 6 cases. Histologically, the lymph nodes were largely obliterated by neoplastic mast cells, while in the spleen, neoplastic cells were multifocally scattered (16/33; 48%), arranged in nodules (10/33; 30%), or obliterated the parenchyma (9/33; 27%). In the liver, the neoplastic cells mainly infiltrated the sinusoids (24/29; 83%), but were also arranged in random nodules (10/29; 34%). Interstitial and nodular metastases were observed in the kidneys and the heart. Grossly unapparent metastases were common in the heart (6/14; 43%), kidneys (4/16; 25%), and lungs (6/9). KIT III and KIT II staining patterns were observed in 29 and 20 cases, respectively.

Sclerosing angiomatoid nodular transformation of the spleen: A case report. / Transformación nodular angiomatoide esclerosante del bazo: reporte de caso.

Sclerosing angiomatoid nodular transformation is a benign vascular pathology of the spleen, developed from the red pulp, of unknown etiology; it is postulated that it may be related to IgG4 disease and Epstein-Barr virus infection. Most cases are asymptomatic, constituting incidental findings in imaging studies. We present a 41-year-old male patient with a history of thyroidectomy for papillary carcinoma who consulted for fever, received symptomatic treatment and performed a computed tomography of the abdomen for nonspecific abdominal symptoms, the same evidence in the lower pole of the spleen a solid-looking image with faint Peripheral enhancement with contrast, measures 62x 52x51 mm. A splenectomy measuring 14x 11x4 cm and weighing 284 grams was performed, identifying a solid, well-defined nodular formation, with a central fibrous-looking area, with whitish tracts that delimited purplish areas. Microscopy: rounded angiomatoid-like coalescing nodules, with vascular proliferation lined by endothelial cells without atypia, interspersed with spindle cells, infiltrated by lymphocytes and macrophages. The stroma between the nodules shows myofibroblastic proliferation with lymphocytes, plasma cells, and siderophages. Immunohistochemistry: positive labeling in vessels for CD34 and CD31, positive sectors for CD8 and negative for CD34. One IgG4 positive cell per high power field. The study for Epstein-Barr by Polymesara Chain Reaction was negative. For the diagnosis, the imaging studies are nonspecific, so the diagnostic confirmation is given by the histopathological study. Splenectomy is curative with no reported cases of malignant transformation or recurrence to date. There are no known risk factors and no triggering factors have been proven, except the association of cases with IgG4 and Ebstein-Barr virus. As it is a recently described pathological entity, it is necessary to collect large series and review our files, reevaluating some of its differential diagnoses to achieve a better understanding of it.

La transformación nodular angiomatoide esclerosante es una patología vascular benigna del bazo, desarrollada a partir de la pulpa roja, de etiología desconocida. Se postula que puede estar relacionada con la enfermedad por inmunoglobulina 4 y la infección por el virus de Epstein-Barr. La mayoría de los casos son asintomáticos, constituyendo hallazgos incidentales en estudios por imágenes. Presentamos el caso de un paciente masculino de 41 años con antecedentes de tiroidectomía por carcinoma papilar que consulta por fiebre. Recibió tratamiento sintomático y se realizó tomografía computarizada de abdomen por síntomas abdominales inespecíficos. La tomografía evidenció una imagen de aspecto sólido, con tenue realce periférico con el contraste que mide 62 por 52 por 51 milímetros en el polo inferior del bazo. Se realizó esplenectomía que midió 14 por 11 por 4 centímetros y pesó 284 gramos. Se identificó una formación nodular sólida, bien delimitada, con área central de aspecto fibroso, con tractos blanquecinos que delimitan áreas violáceas. La microscopía presentó nódulos coalescentes redondeados de aspecto angiomatoide, con proliferación vascular revestida por células endoteliales sin atipia, entremezclados con células ahusadas, infiltrado de linfocitos y macrófagos. El estroma entre los nódulos mostró proliferación miofibroblástica con linfocitos, plasmocitos y siderófagos. Inmunohistoquímica tuvo marcación positiva en los vasos para CD34 y CD31, sectores positivos para CD8 y negativos para CD34. Una célula positiva para inmunoglobulina 4 (IgG4) por campo de gran aumento. El estudio para Epstein-Barr por reacción en cadena de la polimerasa fue negativo. Para el diagnóstico los estudios de imagen son inespecíficos, por lo que la confirmación diagnóstica la da el estudio histopatológico. La esplenectomía es curativa sin casos reportados hasta la actualidad de transformación maligna o recidiva. No se conocen factores de riesgo y no se han comprobado factores desencadenantes, excepto la asociación de casos con IgG4 y virus de Ebstein-Barr. Por ser una entidad patológica recientemente descrita es necesario recopilar series grandes y revisar nuestros archivos, reevaluando algunos de sus diagnósticos diferenciales para lograr una mejor comprensión de la misma.

Transformación nodular angiomatoide esclerosante del bazo: reporte de caso / Sclerosing angiomatoid nodular transformation of the spleen: a case report

La transformación nodular angiomatoide esclerosante es una patología vascular benigna del bazo, desarrollada a partir de la pulpa roja, de etiología desconocida. Se postula que puede estar relacionada con la enfermedad por inmunoglobulina 4 y la infección por el virus de Epstein-Barr. La mayoría de los casos son asintomáticos, constituyendo hallazgos incidentales en estudios por imágenes. Presentamos el caso de un paciente masculino de 41 años con antecedentes de tiroidectomía por carcinoma papilar que consulta por fiebre. Recibió tratamiento sintomático y se realizó tomografía computarizada de abdomen por síntomas abdominales inespecíficos. La tomografía evidenció una imagen de aspecto sólido, con tenue realce periférico con el contraste que mide 62 por 52 por 51 milímetros en el polo inferior del bazo. Se realizó esplenectomía que midió 14 por 11 por 4 centímetros y pesó 284 gramos. Se identificó una formación nodular sólida, bien delimitada, con área central de aspecto fibroso, con tractos blanquecinos que delimitan áreas violáceas. La microscopía presentó nódulos coalescentes redondeados de aspecto angiomatoide, con proliferación vascular revestida por células endoteliales sin atipia, entremezclados con células ahusadas, infiltrado de linfocitos y macrófagos. El estroma entre los nódulos mostró proliferación miofibroblástica con linfocitos, plasmocitos y siderófagos. Inmunohistoquímica tuvo marcación positiva en los vasos para CD34 y CD31, sectores positivos para CD8 y negativos para CD34. Una célula positiva para inmunoglobulina 4 (IgG4) por campo de gran aumento. El estudio para Epstein-Barr por reacción en cadena de la polimerasa fue negativo. Para el diagnóstico los estudios de imagen son inespecíficos, por lo que la confirmación diagnóstica la da el estudio histopatológico. La esplenectomía es curativa sin casos reportados hasta la actualidad de transformación maligna o recidiva. No se conocen factores de riesgo y no se han comprobado factores desencadenantes, excepto la asociación de casos con IgG4 y virus de Ebstein-Barr. Por ser una entidad patológica recientemente descrita es necesario recopilar series grandes y revisar nuestros archivos, reevaluando algunos de sus diagnósticos diferenciales para lograr una mejor comprensión de la misma.

Sclerosing angiomatoid nodular transformation is a benign vascular pathology of the spleen, developed from the red pulp, of unknown etiology; it is postulated that it may be related to IgG4 disease and Epstein-Barr virus infection. Most cases are asymptomatic, constituting incidental findings in imaging studies. We present a 41-year-old male patient with a history of thyroidectomy for papillary carcinoma who consulted for fever, received symptomatic treatment and performed a computed tomography of the abdomen for nonspecific abdominal symptoms, the same evidence in the lower pole of the spleen a solid-looking image with faint Peripheral enhancement with contrast, measures 62x 52x51 mm. A splenectomy measuring 14x 11x4 cm and weighing 284 grams was performed, identifying a solid, well-defined nodular formation, with a central fibrous-looking area, with whitish tracts that delimited purplish areas. Microscopy: rounded angiomatoid-like coalescing nodules, with vascular proliferation lined by endothelial cells without atypia, interspersed with spindle cells, infiltrated by lymphocytes and macrophages. The stroma between the nodules shows myofibroblastic proliferation with lymphocytes, plasma cells, and siderophages. Immunohistochemistry: positive labeling in vessels for CD34 and CD31, positive sectors for CD8 and negative for CD34. One IgG4 positive cell per high power field. The study for Epstein-Barr by Polymesara Chain Reaction was negative. For the diagnosis, the imaging studies are nonspecific, so the diagnostic confirmation is given by the histopathological study. Splenectomy is curative with no reported cases of malignant transformation or recurrence to date. There are no known risk factors and no triggering factors have been proven, except the association of cases with IgG4 and Ebstein-Barr virus. As it is a recently described pathological entity, it is necessary to collect large series and review our files, reevaluating some of its differential diagnoses to achieve a better understanding of it

Role of Suppressor of cytokine signaling 2 during the development and resolution of an experimental arthritis.

Rheumatoid arthritis(RA) is a debilitating chronic inflammatory disease. Suppressors of Cytokine Signaling(SOCS) proteins regulate homeostasis and pathogenesis in several diseases. The intersection between RA pathophysiology and SOCS2 is unclear. Herein, we investigated the roles of SOCS2 during the development of an experimental antigen-induced arthritis(AIA). In wild type mice, joint SOCS2 expression was reduced during AIA development. At the peak of inflammation, SOCS2-/- mice presented with reduced numbers of infiltrated cells in their joints. At the late phase of AIA, however, exhibited increased adhesion/infiltration of neutrophils, macrophages, CD4+-T cells, CD4+CD8+-T cells, and CD4-CD8--T cells associated with elevated IL-17 and IFN-γ levels, joint damage, proteoglycan loss, and nociception. SOCS2 deficiency resulted in lower numbers of apoptotic neutrophils and reduced efferocytosis. The present study demonstrated the vital role of SOCS2 during the development and resolution of an experimental RA model. Hence, this protein may be a novel therapeutic target for this disorder.

Primary splenic histiocytic sarcoma associated with hemophagocytic lymphohistiocytosis: A case report and review of literature of next-generation sequencing involving FLT3, NOTCH2, and KMT2A mutations.

BACKGROUND: Histiocytic sarcoma is a very rare monocyte/macrophage-derived hematopoietic system tumor with a poor prognosis whose diagnosis is pathologically challenging due to its extreme rarity and histological overlap with various mimicking entities in which histiocytes also predominate. CASE: We report the case of a 33-year-old male patient with hemophagocytic lymphohistiocytosis, purpuric syndrome, and significant splenomegaly. The patient underwent splenectomy; subsequent macroscopic examination revealed a spleen weighing 2065 grams with hyperemic red pulp and multiple infarcts at the periphery. The histological and immunohistochemical study established a diagnosis of primary splenic histiocytic sarcoma with frequent hemophagocytosis. Next-generation sequencing demonstrated mutations in FLT3, NOTCH2, and KMT2A, microsatellite stability, and a tumor mutational burden of 2 mut/Mb. The patient's condition deteriorated clinically from the appearance of the first symptoms and he died 6 months later from multi-organ failure. CONCLUSION: Primary splenic histiocytic sarcoma is one of the rarest tumors of the hematopoietic system. We report the first case with mutations in FLT3, NOTCH2, and KMT2A, and associated hemophagocytic lymphohistiocytosis.

Splenic Transcriptional Responses in Severe Visceral Leishmaniasis: Impaired Leukocyte Chemotaxis and Cell Cycle Arrest.

Structural changes in the spleen have been reported in several infectious diseases. In visceral leishmaniasis (VL), a severe parasitic disease caused by Leishmania spp., the loss of white pulp accompanies a severe clinical presentation. Hamster model reproduces aspects of human VL progression. In the early stages, a transcriptomic signature of leukocyte recruitment was associated with white pulp hyperplasia. Subsequently, impaired leukocyte chemotaxis with loss of T lymphocytes in the periarteriolar lymphoid sheath occurred. This differential gene expression was subsequently corroborated by transcriptomic profiling of spleens in severe human VL. At the latest stage, spleen disorganization was associated with increasing clinical signs of VL. White pulp disruption was accompanied by decreased DLK1 expression. The expression of CXCL13, CCR5, CCL19, CCR6, CCR7 and LTA decreased, likely regulated by CDKN2A overexpression. Our findings enlighten a pathway implying cell cycle arrest and decreased gene expression involved in spleen organization.

Estudo retrospectivo de exames histopatológicos esplênicos na rotina laboratorial do Hospital Escola Veterinário UNIFAJ - de 2015 a 2020 / Retrospective study of splenic histopathological examinations in the laboratory routine of the UNIFAJ Veterinary School Hospital from 2015 to 2020 / Estudio retrospectivo de exámenes histopatológicos esplénicos en la rutina de laboratorio del Hospital Escolar Veterinario UNIFAJ desde 2015 a 2020

O baço canino exerce diversas funções, dentre elas linfáticas, hematopoiéticas, imunológicas e circulatórias, sendo que suas características morfológicas e funcionais facilitam a ocorrência de lesões neoplásicas e não neoplásicas. Este trabalho tem como objetivo realizar um estudo retrospectivo dos resultados histopatológicos esplênicos, oriundos do Laboratório do Hospital Escola Veterinário do Centro Universitário de Jaguariúna (HEV- UNIFAJ) Jaguary no período de 2015 a 2020. Foram analisadas 44 amostras esplênicas, nos achados histopatológicos 15/44 (34,1%) se tratavam de neoplasias, 28/44 (63,6%) representaram alterações não neoplásicas, enquanto que 1/44 (2,3%) foi diagnosticado como sítio metastático. Levando em consideração a prevalência das alterações não neoplásica, juntamente com as novas abordagens terapêuticas realizadas na medicina humana, a Medicina Veterinária poderia levar em conta tais fatores na elaboração de modernos planejamentos cirúrgicos e atuais escolhas de tratamentos.(AU)

The canine spleen has several functions, including lymphatic, hematopoietic, immunological and circulatory, and its morphological and functional characteristics facilitate the occurrence of neoplastic and non-neoplastic lesions. This work aims to carry out a retrospective study of splenic histopathological results, from the Laboratory of the Veterinary School Hospital of the Centro Universitário de Jaguariúna (HEV-UNIFAJ) - Jaguary in the period from 2015 to 2020. 44 splenic samples were analyzed, in the histopathological findings 15 / 44 (34.1%) were neoplasms, 28/44 (63.6%) represented non-neoplastic alterations, while 1/44 (2.3%) was diagnosed as a metastatic site. Taking into account the prevalence of non-neoplastic alterations, together with the new therapeutic approaches in human medicine, Veterinary Medicine could take such factors into account in the elaboration of modern surgical plans and current treatment choices.(AU)

El bazo canino ejerce diversas funciones, entre ellas linfáticas, hematopoyéticas, inmunológicas y circulatorias, siendo que sus características morfológicas y funcionales facilitan la occurencia de lesiones neoplásicas y no neoplásicas. Este trabajo tiene como objetivo realizar un estudio retrospectivo de los resultados histopatológicos esplénicos, oriundos del Laboratorio del Hospital Escuela Veterinaria del Centro Universitário de Jaguariúna (HEV-UNIFAJ) - Jaguary en el período de 2015 a 2020. Se analizaron 44 muestras esplénicas, en los hallazgos histopatológicos 15/44 (34,1%) se trataban neoplasias, 28/44 (63,6%) representaron alteraciones no neoplásicas, mientras que 1/44 (2,3%) fue diagnosticado como sitio metastásico. Teniendo en cuenta la prevalencia de las alteraciones no neoplásicas, junto con los nuevos enfoques terapéuticos realizados en la medicina humana, la Medicina Veterinaria podría tener en cuenta tales factores en la elaboración de modernos planes quirúrgicos y actuales opciones de tratamiento.(AU)

Effect of dexamethasone on experimental enteritis produced by Giardia lamblia in a Meriones unguiculatus model.

Our aim was to evaluate the impact of immunosuppression on the development of giardiasis. Thirty-six gerbils (4-6 weeks old) were distributed in four groups containing nine animals each: Control (CT); Control-Infected by Giardia lamblia (CTIn), Immunosuppressed (IS), and Immunosuppressed-Infected by G. lamblia (ISIn). Animals in the IS and ISIn groups received intramuscular dexamethasone solution for 25 days. On the 11th day, the animals in the CTIn and ISIn groups were inoculated with G. lamblia. After 14 days of infection, the 25th day of the experiment, all groups were euthanized. Four hours after euthanasia, the intestinal permeability was evaluated and sections of the duodenum and spleen were harvested for morphometric and histopathological analyses. Immunosuppressed groups showed a significant increase in intestinal permeability compared to control and infected groups. Considering that the infection can become chronic in immunosuppressed groups, we should be alert to the possibilities of chronic inflammatory changes, both locally and systemically, due to the loss of the intestinal barrier. Lesions were observed in the duodenal mucosa of the gerbils of the CTIn group, with reduced villi size, crypt hyperplasia, edema, and the presence of inflammatory infiltrate in the lamina propria. In the ISIn group, we observed no inflammation, long and intact villi, and a significant increase in the area of intestinal mucins, despite the large number of trophozoites identified. Our results suggest that exacerbation of the immune response has a direct relationship with the appearance of lesions during enteritis produced by G. lamblia in the assessed model.