Maria Carolina Ferreira

Structural brain abnormalities are related to retinal nerve fiber layer thinning and disease duration in neuromyelitis optica spectrum disorders

Background: Although aquaporin-4 (AQP4) is widely expressed in the human brain cortex, lesions are rare in neuromyelitis optica (NMO) spectrum disorders (NMOSD). Recently, however, several studies have demonstrated occult structural brain atrophy in NMO. Objective: This study aims to investigate magnetic resonance imaging (MRI) patterns of gray matter (GM) and white matter (WM) abnormalities in patients with NMOSD and to assess the visual pathway integrity during disease duration correlation of the retinal nerve fiber layer (RNFL) and pericalcarine cortex thickness. Methods: Twenty-one patients with NMOSD and 34 matched healthy controls underwent both high-field MRI (3T) high-resolution T1-weighted and diffusion-tensor MRI. Voxel-based morphometry, cortical analyses (Freesurfer) and diffusion-tensor imaging (DTI) analyses (TBSS-FSL) were used to investigate brain abnormalities. In addition, RNFL measurement by optic-coherence tomography (OCT) was performed. Results: We demonstrate that NMOSD is associated with GM and WM atrophy, encompassing more frequently the motor, sensory and visual pathways, and that the extent of GM atrophy correlates with disease duration. Furthermore, we demonstrate for the first time a correlation between RNFL and pericalcarine cortical thickness, with cortical atrophy evolving over the course of disease. Conclusions: Our findings indicate a role for retrograde and anterograde neurodegeneration in GM atrophy in NMOSD. However, the presence atrophy encompassing almost all lobes suggests that additional pathomechanisms might also be involved.

Involvement of Regulatory T Cells in the Immunosuppression Characteristic of Patients with Paracoccidioidomycosis

ABSTRACT Patients with paracoccidioidomycosis (PCM) exhibit a suppression of the cellular immune response characterized by negative delayed-type hypersensitivity (DTH) to Paracoccidioides brasiliensis antigens, the apoptosis of lymphocytes, and high levels of expression of cytotoxic-T-lymphocyte-associated antigen 4 (CTLA-4), interleukin-10 (IL-10), and transforming growth factor β (TGF-β). The aim of this study was to investigate whether and how regulatory T cells (Treg cells) are involved in this immunosuppression by analyzing the number, phenotype, and activity of these cells in patients with active disease (AD group) and patients who had received treatment (TD group). Our results showed that the AD patients had more Treg cells than the TD patients or controls (C group) and also had elevated levels of expression of regulatory markers (glucocorticoid-induced tumor necrosis factor [TNF] receptor-related protein [GITR], CTLA-4, CD95L, LAP-1, and CD38). An analysis of regulatory activity showed that Treg cells from the AD group had greater activity than did cells from the other groups and that cell-cell contact is mandatory for this activity in the C group but was only partially involved in the regulatory activity of cells from AD patients. The addition of anti-IL-10 and anti-TGF-β neutralizing antibodies to the cultures showed that the production of cytokines may be another mechanism used by Treg cells. In conclusion, the elevated numbers of these cells with an increased regulatory phenotype and strong suppressive activity suggest a potential role for them in the immunosuppression characteristic of paracoccidioidomycosis. In addition, our results indicate that while Treg cells act by cell-cell contact, cytokine production also plays an important role.

Characterization of the immune response in human paracoccidioidomycosis

OBJECTIVES Paracoccidioidomycosis (PCM) is a systemic mycosis caused by the dimorphic fungus Paracoccidioides brasiliensis that presents two main clinical forms: the adult form (AF) and the juvenile form (JF); and an asymptomatic form denominated PCM-infection (PI). These forms of PCM are related to the immune response developed after infection, which has been associated with Th1 and Th2 responses. However, some PCM characteristics cannot be explained by this balance. In this study we aimed to complement the characterization of the immune response in PCM, including the newly described T cells subpopulations (Th17, Th9 and Th22). METHODS We analyzed the expression of cytokines and transcription factors characteristics of these different subpopulations of CD4(+) T cells in PBMCs from PCM patients and a PI group. RESULTS The results showed that the PI group presented a predominant Th1 response; that JF patients were characterized by a mixed Th2/Th9 response; and AF patients were characterized by a predominant Th17/Th22 response, as well as substantial participation of Th1 cells. CONCLUSIONS These results contribute to the existing knowledge on the immune responses associated with resistance or susceptibility to the P. brasiliensis infection, and thus could lead to the development of new strategies for patient management.

Effect of low intensity helium-neon (HeNe) laser irradiation on experimental paracoccidioidomycotic wound healing dynamics.

The effect of HeNe laser on the extracellular matrix deposition, chemokine expression and angiogenesis in experimental paracoccidioidomycotic lesions was investigated. At days 7, 8 and 9 postinfection the wound of each animal was treated with a 632.8 nm HeNe laser at a dose of 3 J cm−2. At day 10 postinfection, the wounds were examined by using histologic and immunohistochemical methods. Results revealed that laser‐treated lesions were lesser extensive than untreated ones, and composed mainly by macrophages and lymphocytes. High IL‐1β expression was shown in the untreated group whereas in laser‐treated animals the expression was scarce. On the other hand, the expression of CXCL‐10 was found to be reduced in untreated animals and quite intensive and well distributed in the laser‐treated ones. Also, untreated lesions presented vascular endothelial growth factor (VEGF) in a small area near the center of the lesion and high immunoreactivity for hypoxia‐inducible factor‐1 (HIF‐1), whereas laser‐treated lesions expressed VEGF surrounding blood vessels and little immunoreactivity for HIF‐1. Laser‐treated lesions presented much more reticular fibers and collagen deposition when compared with the untreated lesion. Our results show that laser was efficient in minimizing the local effects observed in paracoccidioidomycosis and can be an efficient tool in the treatment of this infection, accelerating the healing process.

Detection of TCD4+ subsets in human carotid atheroma

Activated TCD4(+) cells are detected in human atherosclerotic plaques which indicate their participation in disease progression and destabilization. Among these cells, IFN-γ-producing T cells (TH1) are recognized as having a pro-atherogenic role. Recently, the IL-17-producing T helper lineage of cells (TH17) has been identified in atherosclerotic lesions. They have been linked to atheroma development through the production of pro-inflammatory mediators present in these lesions. Furthermore, IL-22 producing TCD4(+) cells (TH22) have been identified in the atheromatous environment, but their presence and function has not been investigated. The aim of this study was to analyze the immune response mediated by pro-inflammatory subtypes of TCD4(+) cells in atheromatous lesions. Atherosclerotic plaques of 57 patients with critical stenosis of carotid submitted to endarterectomy were evaluated. Three carotid fragments from organ donors were used as control. mRNA analysis showed expression of TH1 (IFN-γ, T-bet, IL-2, IL-12p35, TNF-α and IL-18); TH2 (GATA-3); TH17 (IL-17A, IL-17RA, Rorγt, TGF-β, IL-6, IL-1β, IL-23p19, CCL20, CCR4 and CCR6) and TH22 (IL-22 and Ahr) related markers. Asymptomatic patients showed higher expression of mRNA of IL-10, TGF-β, CCR4 and GATA-3 when compared to symptomatic ones. Immunohistochemistry analysis showed higher levels of IL-23, TGF-β, IL-1β and IL-18 in macrophages and foam cells in unstable lesions compared to stable and control ones. In vitro stimulation of atheroma cells induced IL-17 and IFN-γ production. Finally we were able to detect, the following subpopulations of TCD3(+) cells: TCD4(+) IFN-γ(+), TCD4(+)IL-17(+), TCD4(+)IL-4(+), TCD4(+)IL-22(+) and double positive cells (IFN-γ/IL-17(+), IFN-γ/IL-22(+) or IL-17/IL-22(+)). Our results showed the presence of distinct TCD4(+) cells subsets in human carotid lesions and suggest that interactions among them may contribute to the atheroma progression and destabilization.