Expression of the urokinase plasminogen activator receptor (uPAR) and its ligand (uPA) in brain tissues of human immunodeficiency virus patients with opportunistic cerebral diseases.

The urokinase plasminogen activator receptor (uPAR) and its ligand (uPA) play an important role in cell migration and extracellular proteolysis. We previously described uPAR/uPA overexpression in the cerebrospinal fluid (CSF) and brain tissues of patients with human immunodeficiency virus (HIV)-related cerebral diseases. In this study, we examined uPAR/uPA expression by immunohistochemistry (IHC) in brains of HIV patients with opportunistic cerebral lesions and in HIV-positive/negative controls. uPAR was found in macrophages/microglia with the highest levels in cytomegalovirus (CMV) encephalitis, toxoplasmosis, and lymphomas; in cryptococcosis and progressive multifocal leukoencephalopathy (PML) cases, only a few positive cells were found and no positivity was observed in controls. uPA expression was demonstrated only in a few macrophages/microglia and lymphocytes in all the cases and HIV-positive controls without different pattern of distribution; no uPA immunostaining was found in cryptococcosis and HIV-negative controls. The higher expression of uPAR/uPA in most of the opportunistic cerebral lesions supports their role in these diseases, suggesting their contribution to tissue injury.

Cellular localization, invasion, and turnover are differently influenced by healthy and tumor-derived extracellular matrix.

The interplay between tumor cells and the microenvironment has been recognized as one of the hallmarks of cancer biology. To assess the role of extracellular matrix (ECM) in the modulation of tissue homeostasis and tumorigenesis, we developed a protocol for the purification of tissue-derived ECM using mucosae from healthy human colon, perilesional area, and colorectal carcinoma (CRC). Matched specimens were collected from the left colon of patients undergoing CRC resection surgery. ECMs were obtained from tissues that were decellularized with hypotonic solutions containing ionic and nonionic detergents, hypertonic solution, and endonuclease in the absence of denaturing agents. Mucosae-derived ECMs maintained distribution and localization of proteins and glycoproteins typical of the original tissues, and showed different three-dimensional (3D) structures among normal versus perilesional and tumor-derived stroma. The three types of ECM differentially regulated the localization and organization of seeded monocytes and cancer cells that were located and organized as in the original tissue. Specifically, healthy, perilesional, and CRC-derived ECMs sustained differentiation and polarization of cancer epithelial cells. In addition, healthy, but not perilesional and CRC-derived ECM constrained invasion of cancer cells. All three ECMs sustained turnover between cell proliferation and death up to 40 days of culture, although each ECM showed different ability in supporting cell proliferation, with tumor>perilesional>healthy-derived ECMs. Healthy-, perilesional- and CRC-derived ECM differently modulated cell homeostasis, spreading in the stroma and turnover between proliferation and death, and equally supported differentiation and polarization of cancer epithelial cells, thus highlighting the contribution of different ECMs modulating some features of tissue homeostasis and tumorigenesis. Moreover, these ECMs provide competent scaffolds useful to assess efficacy of antitumor drugs in a 3D setting that more closely recapitulates the native microenvironment. Further, ECM-based scaffolds may also be beneficial for future studies seeking prognostic and diagnostic stromal markers and targets for antineoplastic drugs.

HIV-1 infected lymphoid organs upregulate expression and release of the cleaved form of uPAR that modulates chemotaxis and virus expression.

Cell-associated receptor for urokinase plasminogen activator (uPAR) is released as both full-length soluble uPAR (suPAR) and cleaved (c-suPAR) form that maintain ability to bind to integrins and other receptors, thus triggering and modulating cell signaling responses. Concerning HIV-1 infection, plasma levels of suPAR have been correlated with the severity of disease, levels of immune activation and ineffective immune recovery also in individuals receiving combination anti-retroviral therapy (cART). However, it is unknown whether and which suPAR forms might contribute to HIV-1 induced pathogenesis and to the related state of immune activation. In this regard, lymphoid organs represent an import site of chronic immune activation and virus persistence even in individuals receiving cART. Lymphoid organs of HIV-1(+) individuals showed an enhanced number of follicular dendritic cells, macrophages and endothelial cells expressing the cell-associated uPAR in comparison to those of uninfected individuals. In order to investigate the potential role of suPAR forms in HIV-1 infection of secondary lymphoid organs, tonsil histocultures were established from HIV-1 seronegative individuals and infected ex vivo with CCR5- and CXCR4-dependent HIV-1 strains. The levels of suPAR and c-suPAR were significantly increased in HIV-infected tonsil histocultures supernatants in comparison to autologous uninfected histocultures. Supernatants from infected and uninfected cultures before and after immunodepletion of suPAR forms were incubated with the chronically infected promonocytic U1 cell line characterized by a state of proviral latency in unstimulated conditions. In the contest of HIV-conditioned supernatants we established that c-suPAR, but not suPAR, inhibited chemotaxis and induced virus expression in U1 cells. In conclusion, lymphoid organs are an important site of production and release of both suPAR and c-suPAR, this latter form being endowed with the capacity of inhibiting chemotaxis and inducing HIV-1 expression.

Nonsebaceous lymphadenoma of salivary gland: report of a case with immunohistochemistry and review of the literature.

OBJECTIVE: Nonsebaceous lymphadenomas are rare benign neoplasms. We emphasize the role of immunohistochemistry and attempt to elucidate the pathogenesis by investigating the distribution of 2 transcription factors, MYC and BLIMP1. STUDY DESIGN: A 70-year-old man was evaluated for a 3-cm left parotid mass. Ultrasound-guided fine-needle aspiration biopsy findings were suggestive of a diagnosis of pleomorphic adenoma. A left superficial parotidectomy was performed, and based on histopathology a diagnosis of lymphadenoma, nonsebaceous type, was rendered. RESULTS: The tumor was positive for AE1/3, CKA, BclII, P63, CD79a, CD3, and MYC; focally positive for CK7 and epithelial membrane antigen; and negative for CD10, calponin, CD117, and BLIMP1. CONCLUSIONS: The rarity of nonsebaceous lymphadenoma and its superficial resemblance to commoner salivary gland tumors may present a diagnostic challenge for pathologists. The expression of MYC in the ductal component and the differentiation-related expression of PRDM1 in the superficial keratinizing layers point to a potential role for these 2 transcription factors in the pathogenesis of this neoplasm.

Stromal phenotype of dental follicle stem cells.

It has been suggested that stem/progenitor cells exist in dental tissue. This study identified adult mesenchymal stem/stromal cell-like populations in the dental follicle of human impacted third molars.The immunohistochemical analysis, of dental follicle using known stem-cell markers: Cytokeratins (AE1-AE3), Smooth Muscle Actin, Ki-67, CD34, CD44, CD45, CD56, and CD133. A positive reaction for at least one of the markers typical of stromal phenotype (CD56, CD44 and CD271) was observed in seven cases . Interestingly, all positive cases showed coexpression of CD44 and CD56, except for one case which was CD56 positive and CD44 negative. Immunohistochemical reaction was negative in all 27 cases for Ki-67, Cytokeratins, Smooth Muscle Actin, CD34, CD133 and CD45. The association: negative for CD34, CD45, CD133, and positive for CD44, CD56 (markers of a subpopulation of stem cells from bone marrow) suggests these may be quiescent mesenchymal stem cells, a hypothesis supported by the negativity of Ki-67 (proliferative index). Our results are compatible with the identification of immature fibroblast cells with phenotypic features of stromal stem cells in the dental follicle.

Flexible argon plasma coagulation treatment of obstructive tracheal metastatic melanoma.

Metastases to the tracheobronchial tree may be considered rare, and melanoma metastases to the trachea are very uncommon. We here report the case of a 61-year-old woman with metastatic melanoma to the trachea occurring 2 years after the excision of a right shoulder skin nodule. The patient underwent argon plasma coagulation (APC) recanalization of the malignant airway under flexible bronchoscopy, which led to the stable resolution of the respiratory symptoms. We also discuss the possible palliative therapeutic options for such metastases, including the APC technique.

Lytic JC virus infection in the kidneys of AIDS subjects.

Our objective was to investigate the role of the human polyomavirus JC virus as a possible cause of renal damage in AIDS subjects. Histology, immunohistochemistry, and molecular biology were used to evaluate the frequency of viral infection, genotypes, viral status, and the presence of rearrangements or point mutations in specific genomic regions of strains isolated from renal tissue. Formalin-fixed, paraffin-embedded sections of postmortem renal specimens obtained from 111 unselected AIDS patients were stained for routine histology and with anti-SV40 antibody. The immunohistochemically positive specimens were further investigated by means of nested polymerase chain reaction for different polyomavirus genomic regions (large T, transcriptional control region, and viral protein 1). Furthermore, the sequences of transcriptional control region and viral protein 1 were also analyzed. Immunohistochemistry was positive in seven cases (6.3%), four of which showed morphological evidence of viral replication (intranuclear inclusion bodies and/or intratubular cellular casts): in all seven cases, only epithelial tubular cells (with and without inclusion bodies) and cellular casts were stained. The JC virus genome was identified by polymerase chain reaction in five of the seven immunohistochemically positive cases; transcriptional control region and viral protein 1 were amplified in, respectively, three and four cases. Transcriptional control region sequence analysis revealed major rearrangements in all three cases, with duplications of all the transcriptional factor-binding sites, whereas no point mutations were found in the viral protein 1 region, which was characterized as Type 1A in all cases. For the first time in AIDS subjects, this study shows that although rarely, JC virus can replicate in renal tissue. Molecular biology revealed major rearrangements in the transcriptional control region that, together with other unknown factors, could justify the increased pathogenicity of this human polyomavirus.

Disseminated microsporidiosis caused by Encephalitozoon cuniculi III (dog type) in an Italian AIDS patient: a retrospective study.

We report a case of disseminated microsporidiosis in an Italian woman with AIDS. This study was done retrospectively using formalin-fixed, paraffin-embedded tissue specimens obtained at autopsy. Microsporidia spores were found in the necrotic lesions of the liver, kidney, and adrenal gland and in ovary, brain, heart, spleen, lung, and lymph nodes. The infecting agent was identified as belonging to the genus Encephalitozoon based on transmission electron microscopy and indirect immunofluorescence. Additional molecular studies, including sequence of the rDNA internal transcribed spacer region, identified the agent as E. cuniculi, Genotype III. We believe that this is the first report of a human case of disseminated microsporidial infection involving the ovary.