Pedro Faísca

Dendritic Cells Genetically Engineered to Express IL-10 Induce Long-Lasting Antigen-Specific Tolerance in Experimental Asthma

Dendritic cells (DCs) are professional APCs that have a unique capacity to initiate primary immune responses, including tolerogenic responses. We have genetically engineered bone marrow-derived DCs to express the immunosuppressive cytokine IL-10 and tested the ability of these cells to control experimental asthma. A single intratracheal injection of OVA-pulsed IL-10-transduced DCs (OVA-IL-10-DCs) to naive mice before OVA sensitization and challenge prevented all of the cardinal features of airway allergy, namely, eosinophilic airway inflammation, airway hyperreactivity, and production of mucus, Ag-specific Igs, and IL-4. OVA-IL-10-DCs also reversed established experimental asthma and had long-lasting and Ag-specific effects. We furthermore showed, by using IL-10-deficient mice, that host IL-10 is required for mediating the immunomodulatory effects of OVA-IL-10-DCs and demonstrated a significant increase in the percentage of OVA-specific CD4+CD25+Foxp3+IL-10+ regulatory T cells in the mediastinal lymph nodes of OVA-IL-10-DC-injected mice. Finally, adoptive transfer of CD4+ mediastinal lymph node T cells from mice injected with OVA-IL-10-DCs protected OVA-sensitized recipients from airway eosinophilia upon OVA provocation. Our study describes a promising strategy to induce long-lasting Ag-specific tolerance in airway allergy.

A case of canine ocular onchocercosis in Portugal.

Onchocercosis is a newly recognized disease in dogs that has been reported with higher frequency in Europe and in the United States. We report a case of a 3-year-old male mongrel stray dog from the Algarve region (South Portugal) who had a retrobulbar granuloma containing a filaroid nematode of the genus Onchocerca. A gravid adult female parasite was embedded in a granulomatous inflammation adjacent to the sclera beyond the retina. The parasite was 191 to 267 mum in diameter (mean = 225 mum), surrounded by a cuticule and owing a uterus that was filled with small unsheated microfilariae. The cuticule consisted of two separated layers in longitudinal sections. The external layer had cuticular ridges and the internal layer contained striations. Sequencing of the COI and ND5 mitochondrial genes confirmed the identity of this parasite as Onchocerca lupi. Furthermore, the first sequence of the 12S mitochondrial gene is reported in this study.

p63 and E-cadherin Expression in Canine Oral Squamous Cell Carcinoma:

The expression of p63 and E-cadherin was studied in 22 oral squamous cell carcinomas in the dog according to immunohistochemical techniques. The association between these markers and clinicopathologic parameters was assessed. All tumor cells studied showed enhanced p63 expression. Regarding E-cadherin expression, 17 of 22 cases (77.3%) showed decreased immunoreactivity, and in 13 of 22 cases (59.1%), its expression was cytoplasmic. Neither p63 nor E-cadherin expression patterns were associated with tumor size, bone invasion, or lymph node metastasis. p63 score was related to proliferating cell nuclear antigen proliferative index (P = .020). A statistically significant correlation between the expression patterns of these 2 markers was noted (P = .026). Furthermore, they were related with tumor grade. An atypical p63 labeling and a cytoplasmic E-cadherin staining were statistically related with a higher tumor grade (P = .022 and P = .017, respectively). These findings suggest that changes in p63 and E-cadherin expression are frequent events in oral squamous cell carcinoma in dogs.

PCNA and grade in 13 canine oral squamous cell carcinomas: association with prognosis.

This study evaluated the prognosis factors of age, tumour size, anatomic location, histological grade and proliferating cell nuclear antigen (PCNA) expression in 13 dogs with oral squamous cell carcinoma (OSCC) with bone invasion and without signs of lymph node or distant metastasis. All animals were treated with radical excision performed with at least 1 cm margin, based on computed tomography images. In the 2-year follow-up, median disease-free survival was 138 days for dogs with grade 3 tumours and was not reached for those with grade 2 tumours. Grade 3 tumours and PCNA labelling index ≥65% were related with a shorter disease-free survival time and consequently poor prognosis (p = 0.003 and p = 0.034, respectively). Mean PCNA labelling index was significantly higher in recurrent cases (p = 0.011). Histological grade and PCNA expression may be important prognosis factors in canine OSCC.

Immortalization and characterization of a new canine mammary tumour cell line FR37-CMT.

Here we describe the establishment of a new canine mammary tumour (CMT) cell line, FR37-CMT that does not show dependence on female hormonal signaling to induce tumour xenografts in NOD-SCID mice. FR37-CMT cell line has a stellate or fusiform shape, displays the ability to reorganize the collagen matrix, expresses vimentin, CD44 and shows the loss of E-cadherin which is considered a fundamental event in epithelial to mesenchymal transition (EMT). The up-regulation of ZEB1, the detection of phosphorylated ERK1/2 and the downregulation of DICER1 and miR-200c are also in accordance with the mesenchymal characteristics of FR37-CMT cell line. FR37-CMT shows a higher resistance to cisplatin (IC50 >50 µM) and to doxorubicin (IC50 >5.3 µM) compared with other CMT cell lines. These results support the use of FR37-CMT as a new CMT model that may assist the understanding of the molecular mechanisms underlying EMT, CMT drug resistance, fostering the development of novel therapies targeting CMT.

Low-dose ionizing radiation induces therapeutic neovascularization in a pre-clinical model of hindlimb ischemia

Aims We have previously shown that low-dose ionizing radiation (LDIR) induces angiogenesis but there is no evidence that it induces neovascularization in the setting of peripheral arterial disease. Here, we investigated the use of LDIR as an innovative and non-invasive strategy to stimulate therapeutic neovascularization using a model of experimentally induced hindlimb ischemia (HLI). Methods and results After surgical induction of unilateral HLI, both hindlimbs of female C57BL/6 mice were sham-irradiated or irradiated with four daily fractions of 0.3 Gy, in consecutive days and allowed to recover. We demonstrate that LDIR, significantly improved blood perfusion in the murine ischemic limb by stimulating neovascularization, as assessed by laser Doppler flow, capillary density, and collateral vessel formation. LDIR significantly increased the circulating levels of VEGF, PlGF, and G-CSF, as well as the number of circulating endothelial progenitor cells (EPCs) mediating their incorporation to ischemic muscles. These effects were dependent upon LDIR exposition on the ischemic niche (thigh and shank regions). In irradiated ischemic muscles, these effects were independent of the recruitment of monocytes and macrophages. Importantly, LDIR induced a durable and simultaneous up-regulation of a repertoire of pro-angiogenic factors and their receptors in endothelial cells (ECs), as evident in ECs isolated from the irradiated gastrocnemius muscles by laser capture microdissection. This specific mechanism was mediated via vascular endothelial growth factor (VEGF) receptor signaling, since VEGF receptor inhibition abrogated the LDIR-mediated gene up-regulation and impeded the increase in capillary density. Finally, the vasculature in an irradiated non-ischemic bed was not affected and after 52 week of LDIR exposure no differences in the incidence of morbidity and mortality were seen. Conclusions These findings disclose an innovative, non-invasive strategy to induce therapeutic neovascularization in a mouse model of HLI, emerging as a novel approach in the treatment of critical limb ischemia patients.

First report of Knemidokoptes jamaicensis Turk, 1950 (Acari: Epidermoptidae) infection in Palearctic tits (Passeriformes: Paridae) Parus major L., 1758 and Cyanistes caeruleus (L., 1758) in Portugal

ABSTRACT Wild birds may show skin lesions caused by different pathogens, such as parasitic mites. During 4 years, 32,569 birds of 156 species were captured across Portugal at several habitat types, and skin samples were collected whenever cutaneous lesions were present. Skin scrapings and skin histology revealed the presence of Knemidokoptes mites identified as K. jamaicensis Turk, 1950 in a great tit Parus major L., 1758 and in a blue tit Cyanistes caeruleus (L., 1758), presenting crusty and proliferative lesions on legs and feet. Both birds were captured in Arzila, Portugal. The presence of these mites may be related to the use of artificial bird feeders by these species. To the authors’ knowledge, this is the first report of Knemidokoptes mites in wild birds from Portugal and the first report of this infestation in these two host species.

Parotid Salivary Duct Stenosis following Caudal Maxillectomy

Parotid salivary duct dilation was diagnosed in a 9-year-old male dog. The dog had undergone caudal maxillectomy on the ipsilateral side 2-years prior to presentation. Treatment consisted of parotid salivary duct excision and superficial parotidectomy that lead to the resolution of clinical signs. Transient facial neuropraxia was observed immediately after surgery and resolved spontaneously after 2-weeks. Parotid salivary duct dilation should be considered as a chronic postoperative complication following caudal maxillectomy.