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BACKGROUND: An increasing number of coronavirus disease 2019 (COVID-19) related autoimmune hepatitis (AIH) and autoimmune liver disease (AILD) has been already described so far in the last three years. This rise has set up some diagnostic and therapeutic concerns, although steroid therapy has mostly been efficient, avoiding main significant side effects. CASE PRESENTATION: We report the case of a 52-year-old subject displaying liver function impairment at the laboratory tests while positive for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) swab. Needle liver biopsy showed severe portal inflammation, interface hepatitis, lobular inflammation, abundant plasma cells, bridging necrosis, endothelialitis, bile duct vanishing disease, and ductular reaction. The diagnosis of autoimmune liver disease (AILD) was performed. After a month of steroid and ursodeoxycholic acid medications, liver function fully recovered. Azathioprine was introduced, and steroids were gradually reduced. CONCLUSIONS: Probably triggered by the SARS-CoV-2-induced cytokine storm, the association between COVID-19 and autoimmune-related inflammatory injury may display a particular paradigm of AILD pathogenesis. [ABSTRACT FROM AUTHOR]

OBJECTIVE: ISL1 is a pioneer transcription factor that plays important roles in cell lineage specification and differentiation, by programming the epigenome and recruiting additional regulatory factors. The aim of this study is to determine whether the human breastmilk contains ISL1-positive stem cells, and, if so, to describe the subcellular localization of ISL1. MATERIALS AND METHODS: Breast milk was obtained from fourteen healthy females during the first 2-6 months of lactation. Cell morphology was examined in the breast milk with the automatic ThinPrep® processor (Hologic® Inc.) in commercial Cytological ThinPrep® solution (Hologic ® Inc.), followed by standard immunohistochemical staining of ISL1. RESULTS: ISL1 had a granular diffuse cytoplasmic localization, with varying intensity of staining in both single and grouped cells. Nuclear staining was also present, as was staining of intracellular and extracellular vesicles with ISL1 antibody. CONCLUSIONS: These preliminary results suggest that ISL1 could distinguish a readily available source of putative stem cells in human breast milk. These stem cells may complete the network created between the mother and the newborn during gestation, thereby improving the efficiency of programming and reprogramming postnatal events. [ABSTRACT FROM AUTHOR]

OBJECTIVE: The notochord acts as a patterning structure, playing a key role in the formation of the vertebral column, both indirectly by inducing sclerotome cell differentiation and directly by forming the nucleus pulposus of intervertebral discs. The abnormal development of the notochord results in an easy equation with a variety of birth defects. Therefore, we focused our attention on the analysis of the early stages of human notochord development by highlighting the role of progenitor stem cells involved in the origin of intervertebral discs (IVDs). MATERIALS AND METHODS: Eight human fetuses, ranging from 8 up to 21 weeks of gestational age, were obtained from spontaneous abortion or voluntary interruption of gestation. Samples were 10% formalin-fixed, routinely processed, and paraffin-embedded. Five micron- tick paraffin sections were obtained from each sample. Sections were stained with hematoxylin- eosin and PAS stain for a morphological examination. Tissue samples were immunostained with a commercial anti-human CD44 rabbit monoclonal antibody at 1:100 dilution. RESULTS: Immunoreactivity for CD44 was detected in six out of eight notochords examined in this study. Reactivity for CD44 was restricted to progenitor cells giving rise to the nucleus pulposus (NP) of the developing IVDs. Positive cells showed a membranous and/or cytoplasmic immunostaining, no reactivity was observed in the nuclear compartment. CD44 expression was always restricted to IVD precursor cells, whereas cartilage precursors were devoid of labelling. CONCLUSIONS: Our study shows, for the first time, that the stem cell marker CD44 selectively marks intervertebral disc progenitor cells, paralleling their differentiation toward a discogenic phenotype. Therefore, our results suggest that CD44 plays a key role in IVD development, allowing its differentiation from surrounding undifferentiated notochordal cells toward a IVD phenotype. Given the role of CD44 in IVD development, we may hypothesize that low CD44 levels might be associated with changes in IVD development and with susceptibility to develop back pain later in life. [ABSTRACT FROM AUTHOR]

OBJECTIVE: L1 cell adhesion molecule (L1CAM) is a glycoprotein characterized by three components: an extracellular region, a transmembrane segment, and a cytoplasmic tail. L1CAM is expressed in multiple human cells, including neurons. The neural cell adhesion molecule L1 has been implicated in a variety of neurologic processes, including neuritogenesis and cerebellar cell migration. The presence of L1CAM on the surface of nerve cells allows the adhesion of neurons among them. Furthermore, when it is bound to itself or to other proteins, L1-CAM induces signals inside the cell. The aim of this work was to study L1CAM expression in the human spinal cord during development, at different gestational ages, through immunohistochemistry. MATERIALS AND METHODS: Immunohistochemical analysis for L1CAM was performed in five human spinal cord samples, including three embryos and two fetuses of different gestational ages, ranging from 8 to 12 weeks. RESULTS: L1CAM expression was detected in all 5 spinal cords examined in this study. The adhesion molecule was found in the vast majority of cells. The highest levels of immunoreactivity for L1CAM were detected at the periphery of the developing organs, in the spinal cord zones occupied by sensory and motor fibers. In the alar and basal columns, immunoreactivity for L1CAM was characterized by a reticular pattern, being mainly expressed in axons. Strong reactivity of L1CAM was also found in extracellular vesicles. This extracellular localization might indicate the ability of L1CAM to mediate the transduction of extracellular signals that support axon outgrowth. CONCLUSIONS: The high reactivity of L1cam in the axons of developing neurons in the fetal spinal cord confirms previous studies on the ability of L1CAM to promote axon sprouting and branching in the developing nervous system. In this work, a new actor is reported to have a role in the complex field of human spinal cord development: L1CAM, whose expression is highly found in the developing neuronal and glial precursors. [ABSTRACT FROM AUTHOR]

OBJECTIVE: L1 cell adhesion molecule (L1CAM) is a member of the immunoglobulin superfamily of cell adhesion molecules. The present study investigated the expression of L1CAM during the development in the fetal human kidney at different gestational ages, to reach a better knowledge on the role of L1CAM in renal morphogenesis. MATERIALS AND METHODS: The immunohistochemical analysis for L1CAM was performed in 24 fetal kidneys of different gestational ages, ranging from 10 to 38 weeks. L1CAM expression was observed in all 24 kidneys examined. RESULTS: Immunoreactivity for L1CAM was restricted to the collecting tubules, of the developing fetal kidneys. Moreover, L1CAM was detected in the ureteric bud tips, near the subcapsular metanephric mesenchymal stem/progenitor cells. L1CAM was also expressed in the collecting tubules undergoing fusion with the distal tubules of the developing nephrons. L1CAM was mainly expressed along the cell membrane. In fetal kidneys in which the renal pelvis was observed, epithelial cells of the renal pelvis showed strong membranous reactivity for L1CAM. CONCLUSIONS: Our study shows that L1CAM is expressed in all stages of human kidney nephrogenesis, being restricted to the renal structures derived from the ureteric bud. The expression of L1CAM in the cells of the ureteric bud tips suggests a major role for this adhesion molecule in the induction of metanephric mesenchymal cells to undergo mesenchymal-to-epithelial transition and differentiation into new nephrons. The interindividual variability in L1CAM expression observed in this study might be related to different levels of nephrogenesis, suggesting L1CAM involvement in the fetal programming of adult kidney diseases. [ABSTRACT FROM AUTHOR]

OBJECTIVE: Acyl-CoA-binding protein (ACBP), also known as diazepam binding inhibitor (DBI), is a small phylogenetically conserved protein. This ancestral peptide is multifunctional, performing intracellular activities as ACBP protein or extracellular roles as DBI. Several studies showed its endless facets, including a relevant activity as appetite stimulator and as anabolic factor. High levels of ACBP have been described in erythrocytes, liver, kidney, and gut cells. The aim of this study was to analyze, at immunohistochemical level, the expression of ACBP in fetal human tissues during development, focusing on the developing kidney. MATERIALS AND METHODS: Immunohistochemistry for ACBP was performed on 30 human fetal kidneys, from 15 fetuses of gestational age ranging from 13 to 19 weeks. At autopsy, all kidney samples were 10% formalin-fixed, routinely processed and paraffin-embedded. Five micron-thick paraffin sections were stained with Hematoxylin and Eosin and PAS stain for a morphological examination. RESULTS: ACBP was detected in all 30 kidneys analyzed in this study. No significant changes in ACBP expression were observed at different gestational ages. Immunostaining for ACBP was restricted to the epithelium covering the renal pelvis, the papillae, the collecting tubules, and the proximal and distal tubules. On the other hand, medullary regions and in the metanephric mesenchymal stem/progenitor cells did not show any reactivity for ACBP. CONCLUSIONS: According to our findings, ACBP should be considered as a new player in the complex field of human nephrogenesis, given that it was detected in all fetal kidneys immunostained. Its preferential localization in the renal structures derived from the Wolf duct, such as pelvis epithelium and collecting ducts, suggests a major role for ACBP in the induction of the metanephric mesenchymal cells toward the differentiation into glomerular structures. ACBP expression in proximal and distal tubules, two structures originating from the metanephric mesenchyme, indicates a further role of this protein in nephron development. In conclusion, ACBP should be added to the multiple molecules involved in human nephrogenesis. [ABSTRACT FROM AUTHOR]

OBJECTIVE: Previous studies have confirmed the key mechanism by which SARS-CoV-2 enters human cells. It is well established that ACE2 is the receptor that can mark the beginning of the infection. In light of this, the organs that express higher levels of ACE2 are generally considered at higher risk, while those with lower levels should be somehow more protected. This - if related to the scarcity of ace2-expressing cells in the brain - seems to contrast with the presence of a variety of neurological symptoms that follow infection with ace2. The aim of this work was to analyze ACE2 expression in the human brain, focusing on the choroid plexuses. PATIENTS AND METHODS: Twenty brain samples were obtained at autopsy from ten human fetuses and from ten adult subjects. All samples were selected to contain the choroid plexus. Specimens were fixed in 10% formalin, routinely processed and paraffin embedded. 5-micron sections were stained with Hematoxylin and Eosin (H&E) and immunostained with a commercial anti-human ACE2 rabbit monoclonal antibody at 1:100 dilution. RESULTS: We analyzed 20 samples by immunohistochemistry, and we noted that, as far as fetal samples are concerned, a strong reactivity for ACE2 was detected in the myxoid stroma of the choroid plexuses and in the endothelial cells in fetuses. The complete absence of the ACE2 marker was detected in epithelial cells, neurons and glial cells of the cerebral cortex, both in fetuses and in adults. Whereas a strong but selective reactivity for ACE2 was also detected in adult choroid plexuses, mainly localized in the endothelial cells of the choroid capillaries. CONCLUSIONS: Our study shows a strong expression of ACE in the fetal and adult brain choroid plexuses. This new histopathological finding may clarify the susceptibility of the human brain to SARS-COV-2 infection. Our data indicate the choroid plexus as the entry gate of virus for in the human brain; therefore, the entrance of SARS-CoV-2 into the cerebrospinal fluid through the choroid plexuses might represent the mechanism utilized by this coronavirus to cause direct injury to brain cells. [ABSTRACT FROM AUTHOR]

OBJECTIVE: The ongoing Coronavirus pandemic (COVID-19) showed similar characteristics with the severe acute respiratory syndrome (SARS). In the most compromised cases, COVID-19 infection leads to death due to severe respiratory complications. COVID-19-related acute respiratory distress syndrome (ARDS) is the primary cause of death in these patients. In the present study, we show an ultrastructural analysis on the lungs of a patient affected by COVID-19. PATIENTS AND METHODS: Lung specimens obtained at autopsy from a 63-years old patient affected by COVID-19 were fixed in 1% paraformaldehyde. Slices of 300 µm thickness were dehydrated and dried by Critical Point Drying in CO2. Slices were covered with a conductive gold film approximately 30 nm thick and observed at a Zeiss Sigma 300 SEM FEG in the secondary electron (SE) and backscattered electron (BSE) modes. As case control a lung biopsy from a 60-year-old man was considered. RESULTS: At low power in all COVID-19 lung specimens severe changes in the pulmonary architecture were found, due to the collapse of air spaces. Moreover, alveolar cavities were covered by large membranes. At high power, alveolar membranes showed a fibrillar structure, suggestive of a loose network of fibrin. It has been also found that intra-alveolar red blood cells were frequently present in the alveolar spaces, surrounded by a reticular fibrin network, suggestive for fibrin-hemorrhagic alveolitis. Alveolar changes were constantly associated with pathological features related to the pulmonary vessels. Vascular changes were prominent, including endothelial damage and thrombosis of large pulmonary vessels. Fibrinous microthrombi were frequently detected in the inter-alveolar septal capillaries. In addition, it has been frequently detected capillary proliferation in the alveolar septa with finding suggestive for intussusceptive neo-angiogenesis. CONCLUSIONS: In conclusion, our electron microscopy analysis showed that COVID-19-related lung disease is characterized by a substantial architectural distortion, with the interactions between alveolar and vascular changes. Intra-alveolar hyaline membranes are associated with macroand micro-thrombotic angiopathy, ending with capillary proliferation. The new blood vessel formation originates from the septa and extends into the surrounding parenchyma. Our findings confirm previous reports on the specificity of the multiple and complex morphological pattern typical, and apparently specific, of COVID-19-related lung disease. [ABSTRACT FROM AUTHOR]

OBJECTIVE: Colorectal cancer (CRC) is a complicated tumor, involving several oncogenic signaling pathways, and with a molecular mechanism not fully understood yet. The implication of thymosin β4 (Tβ4) with tumor in-surgence and in migration of CRC cells was evidenced in the past with different methodologies, while Tβ10 connection with CRC has been sporadically investigated. This study focused on the implication of both types of thymosin in CRC progression and invasion by analyzing the changes in their levels according to different zones of the tumor, and to Dukes stage and budding index. PATIENTS AND METHODS: Tβ4 and Tβ10 were analyzed in deep and superficial tumor samples, and normal mucosa from 18 patients. Concentrations of Tpβ and Tβ10 have been measured by high-pressure liquid chromatography (HPLC) coupled to electrospray-ion trap mass spectrometry (ESI-IT-MS). Ms data were compared by f-test and ANOVA statistical analysis. Identification of thymosin and their proteo-forms has been performed by HPLC-high reso-lution-ESI-IT-MSMS. RESULTS: Both Tβ4 and Tβ10, exhibited intra-tumoral quantitative differences, being up-regulated in the deep part of the CRC. They exhibited, moreover, strong association with the Dukes stage and the budding grade, being more concentrated in patients at Dukes stage B and with budding index "2". CONCLUSIONS: The results obtained in the present investigation encouraged the hypothesis that the two thymosin are involved in colorectal cancer progression, and in promoting cancer invasion. Thus, they are good candidates to be diagnostic/prognostic biomarkers and therapy targets. [ABSTRACT FROM AUTHOR]