Caterina Camastra

New evidence for a critical role of elastin in calcification of native heart valves: immunohistochemical and ultrastructural study with literature review.

Perrotta I, Russo E, Camastra C, Filice G, Di Mizio G, Colosimo F, Ricci P, Tripepi S, Amorosi A, Triumbari F & Donato G
(2011) Histopathology59, 504–513

Protective activity of α-lactoalbumin (ALAC), a whey protein rich in tryptophan, in rodent models of epileptogenesis

The aim of the present work was to evaluate the potential activity of α-lactoalbumin (ALAC), a whey protein rich in tryptophan (TRP), in two rodent models of epileptogenesis and we explored a possible mechanism of action. The effects of ALAC (oral administration) were tested in two standard epileptogenesis protocols, namely the pilocarpine post-status epilepticus model in mice and the WAG/Rij rat model of absence epileptogenesis. The mechanism of action was investigated by assessing the effects of ALAC in two seizure models (N-methyl-d-aspartate (NMDA) and pentylenetetrazol (PTZ) -induced seizures) including d-serine co-administration. ALAC showed protecting properties in both models of epileptogenesis, reducing spontaneous seizures development. In acute seizure models, ALAC possessed antiseizure properties at some of the doses tested (PTZ-seizures: >50% seizure-reduction between 250 and 375 mg/kg; NMDA-seizures: >90% reduction at 250 and 500 mg/kg). When a dose of d-serine ineffective per se was co-administered with ALAC, ALAC effects were significantly reversed in both models. ALAC is active in experimental models of seizure and epileptogenesis. Its effects are likely mediated by the inhibition of NMDA receptors at the glycine binding site, possibly secondarily to the in vivo enzymatic conversion of ALAC-generated tryptophan to kynurenic acid. However, other mechanisms of action contributing to ALAC effects cannot be excluded.

The mTOR signaling pathway and neuronal stem/progenitor cell proliferation in the hippocampus are altered during the development of absence epilepsy in a genetic animal model

Hyperactivation of mammalian target of rapamycin (mTOR) signaling pathway occurs after an epileptogenic insult and, its inhibition prevents the development of spontaneous seizures. We have recently demonstrated that mTOR’s inhibition by rapamycin (started before seizure onset), permanently reduces the development of spontaneous absence seizures in WAG/Rij rats, an animal model of absence epilepsy; furthermore, mTOR phosphorylation was increased in adult WAG/Rij rats’ cortex, but not other brain areas. However, it was not clear whether this hyperphosphorylation was a cause or a consequence of absence seizure. Here, we have addressed this issue by analyzing immunohistochemically: (1) the brain levels of total and phosphorylated mTOR in young (before seizures) and adult WAG/Rij rats; (2) the proliferation of hippocampal neuronal stem/progenitor cells assessed by BrdU analysis at different ages. WAG/Rij rats have higher levels of total mTOR in several brain areas than Wistar rats; phospho-mTOR staining is higher in young WAG/Rij rats than control and adult WAG/Rij rats. Finally, the age-related decline in hippocampal neural progenitor cell proliferation rate was slower in WAG/Rij than Wistar rats. Our results support a role for persistent mTOR activation and consequent change in hippocampal progenitor cell proliferation during the epileptogenic process leading to the development of absence seizures in WAG/Rij rats.

A reappraisal of macrophage polarization in glioblastoma: Histopathological and immunohistochemical findings and review of the literature

The survival rate in glioblastoma multiforme patients has scarcely improved in the last decades; however, many new therapeutic strategies have been theorized or developed for these neoplasias. Recently, the inverse correlation observed between patient prognosis and tumor-associated macrophages (TAMs) density in solid tumors has encouraged the development of anti-tumor strategies aiming to target TAMs. As expected, TAMs polarization is influenced by both macrophage localization and tumor microenvironment signals, resulting in a more complex scenario than the simple M1/M2 activation status. Macrophage polarization in glioblastoma has not yet been fully elucidated, and most results have been obtained in experimental non-human settings, with some apparent contradiction. The authors performed a histopathological and immunohistochemical study of 37 cases of glioblastoma in order to characterize the M1 and M2 macrophage populations within TAMs. A high prevalence of CD163+ M2-polarized macrophages was detected in this cohort, whereas iNOS+ macrophages were rarely found. The down-regulation of CD68 expression in microglia/macrophage infiltrating glioblastomas is also reported for the first time. Such a finding is associated with a specific location of TAMs within the lesion, as confirmed by the fact that CD68 staining was lower than CD163, mainly in perivascular areas. The authors discuss the recent literature about the global scenario of macrophage plasticity and polarization in glioblastoma, and suggest some pivotal points for therapeutic applications.

Elastofibroma Dorsi: A Histochemical and Immunohistochemical Study

Elastofibroma dorsi (ED) is considered a member of a heterogeneous group of benign fibrous (fibroblastic or myofibroblastic) softtissue tumors, frequently localized in the periscapular region in middle aged or older individuals. However, the pathogenesis of ED is still unclear and many authors believe that ED results from a reactive hyperproliferation of fibroblastic tissue, while others suggest that it may be a consequence of a mechanical friction. In our study, we examined 11 cases of ED using histochemical and immunohistochemical methods, in order to extend the knowledge about extracellular matrix composition and histopathogenesis of ED. From the results it appeared that stroma and interspersed spindle cells of ED were positive for both periostin and tenascin-C. Mast cells tryptase-positive were also abundant throughout the lesion. The perivascular distribution of periostin and tenascin-C, associated with the CD34 positivity, suggest that endothelial-mesenchymal transition events can account for neovascularization and production of fibroelastic tissue characteristic of elastofibroma. Our data obtained in endothelial cells cultures demonstrated that elastin production is higher when the status of confluence of the cells is low. So, we can assume that such a phenomenon is a characteristic of mesenchymal/endothelial cells CD34 positive, in which elastin production results to be inversely proportional to the vascular differentiation of cellular elements. In the light of these considerations, we think that a cancerous nature of ED is unlikely. Overall, our study report, for the first time, a detailed description of extracellular matrix composition in ED, suggesting that a mechanical strain-dependent reactivation of periostin and tenascin-C expression, as well as of elastin deposition, could be responsible for development of ED.

The role of mast cell tryptases in cardiac myxoma: Histogenesis and development of a challenging tumor.

A number of available studies have focused on the role of mastocytes and their angiogenic factors, such as tryptase expression, in cancer growth as a major research objective. Cardiac myxoma is a rare neoplasia and is the most common primary tumor of the heart. The cellular elements of cardiac myxoma have an endothelial phenotype; however, its histogenesis remains unclear. Currently, no available studies have correlated the pathological characteristics of cardiac myxomas, such as cell differentiation and vascularization, with the angiogenic factors of mast cells. The aim of the present study was to investigate the role of mast cell tryptases on the development of cardiac myxomas and examine the histogenesis of tumoral cells. A series of 10 cardiac myxomas were examined by immunohistochemical analysis for the presence of tryptase-positive mast cells. Statistical analysis of our data demonstrated that angiogenesis and the development of pseudovascular structures were correlated with the number of tryptase-positive mast cells. Therefore, we hypothesize that cardiac myxoma cells are endothelial precursors which are able to generate mature vascular structures. Further morphological and immunophenotypic analyses of tumoral cells may corroborate such a hypothesis.

Innate immunity in cutaneous melanoma

The skin immune system is composed of a vast network of immune cells, including lymphocytes, macrophages, neutrophils, dendritic cells and Langerhans cells, which not only are involved in inflammatory responses but also contribute to homeostatic function and may participate in the various steps of carcinogenesis. Many studies support the notion that innate immunity has a key role in the development, growth and prognosis of cutaneous malignant melanoma (MM), through the release of pro‐ and/or anti‐inflammatory cytokines and tumour growth factors. The tumour environment in a major subset of cutaneous MM shows evidence of a T cell‐infiltrated phenotype, but there is less known about the presence and the phenotype of other immune system cells. Response to immunotherapy is largely correlated with the presence of T cells in the tumour microenvironment, while the regulation exerted by stromal components such as macrophages and mast cells has been less investigated. In the current report, we review the recent literature, focusing our attention on the role of macrophages, dendritic cells, mast cells and natural killer cells in orchestrating MM progression, to better understand tumour immunobiology. The identification of new therapeutic targets and the application of approaches aimed at modulating crosstalk between immune and tumour cells, could have a crucial impact on immunotherapy and result in better clinical outcome. We hope this review will be helpful in cutaneous MM research.

Inflammation and macrophage polarization in cutaneous melanoma: Histopathological and immunohistochemical study

Tumor-associated macrophages (TAMs) are considered to affect tumor growth and progression. Macrophages can be classified into two states of polarized activation, namely classically activated M1 macrophages and alternatively activated M2 macrophages. The dynamic balance between TAMs and tumor cells has an important impact on tumor homeostasis and progression. The aim of this study was to characterize the phenotype of TAMs present in different subtypes of superficial spreading cutaneous melanoma and their relationship with the lymphocytic infiltrate in order to identify new histopathological tools for melanoma prognosis and suitable targets for melanoma therapy. We selected four groups of patients with malignant melanoma in order to analyze the profile of polarized macrophage activation using immunohistochemical methods. Histopathological analysis showed that the macrophage polarization state appears to be more related to the lymphocytic infiltrate than to the thickness of the lesions. Further studies are necessary to increase understanding of the immunopathological dynamic of melanoma that may be modulated by future targeted immunotherapies.

Non-invasive real-time biopsy of intracranial lesions using short time expanded circulating tumor cells on glass slide: report of two cases

BackgroundCirculating Tumor Cells (CTCs) are promising biomarkers for monitoring solid cancer and were used to monitor brain tumors. Here we report two cases in which, for the first time, CTCs were used in cytological diagnostic evaluation to discriminate a space-occupying lesion of the brain.Case presentationTwo cases of focal intracranial lesions, unclassified for diagnosis, untreated and apparently symptomatic, were examined after high-contrast resolution Magnetic Resonance Imaging and/or Computed Tomography scans. CTCs were seeded on chamber slides and short-time expanded under the optimized conditions as we previously reported. The first case was a focal lesion localized in the parietal-occipital area in a 67-year-old woman. The second case was a 31-year-old man with an expansive intracerebral lesion localized in the left peri-trigonal area. Both patients underwent excisional biopsy. Histopathological evaluation of the biopsy confirmed the previous cytological diagnoses, and the analysis of the clinical outcomes retrospectively validated both diagnoses.ConclusionsThe cases here reported illustrate the potential for using expanded CTCs as non-invasive, real-time biopsy. Moreover, non-invasive real-time biopsy can represent an alternative diagnostic tool to be used when a functional area of the brain is at risk of injury from excisional biopsy procedures.

Deregulation of SGK1 in Ulcerative Colitis: A Paradoxical Relationship Between Immune Cells and Colonic Epithelial Cells

Background Inflammatory bowel disease (IBD) is due to the interaction of genetic and environmental factors that trigger an unbalanced immune response ultimately resulting in the peculiar inflammatory reaction. Experimental models of IBD point to a role of T-cell-derived cytokines (Th17) and to SGK1 as mediator of the Th17 switch. We hypothesize that SGK1, a salt inducible kinase, directs lymphocytic behavior and tissue damage. Methods Eleven controls and 32 ulcerative colitis (UC) patients were randomized according to endoscopic Mayo score. Mucosal biopsies from different intestinal tracts were analyzed by immunohistochemistry and quantitative real-time polymerase chain reaction to check the expression of disease markers including SGK1. Peripheral blood mononuclear cells (PBMCs) from patients and controls were analyzed by fluorescence-activated cell sorting. Finally, an in vitro cell model was developed to test the hypothesis. Results SGK1 mRNA and protein expression in lesional areas of UC patients were lower than in normal peri-lesional areas of the same patients and in normal tissues of healthy controls. SGK1 expression was increased in PBMCs from UC patients, particularly in the CD4+ cell population, enriched in Th17 cells. IL17/IL13 was increased in patients and correlated with SGK1 expression. Genetically engineered Jurkat cells confirmed the effect of SGK1 overexpression on viability of RKO cells. Conclusions These observations suggest a pathogenic mechanism whereby SGK1 overexpression in CD4+ T cells induces the secretion of the inflammatory cytokines IL17 and IL13, which downregulate the expression of SGK1 in target tissues. Our data suggest a novel hypothesis in the pathogenesis of UC, integrating colonic epithelial cells and lymphocytes.