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- Recurrent focal myositis: a rare inflammatory myopathyPublication . Teixeira, F.; Peixoto, D.; Costa, J.; Bogas, M.; Taipas, R.; Melo-Pires, M.; Afonso, C.; Araújo, D.Focal myositis is an acute and localized muscle inflammation of unknown aetiology. The clinical diagnosis is often difficult to obtain, since it can be confused with infections, vascular thrombosis or muscle tumours such as sarcomas. This leads to a significant delay in the diagnosis, resulting in the administration of inappropriate and potentially harmful treatments. We report here a case of recurrent focal myositis in a woman where the diagnosis was only obtained after 6 years, despite multiple hospital admissions. This case reinforces the importance of clinical knowledge and experience to tackle challenging medical scenarios
- Acute ischemic stroke secondary to glioblastoma. A case reportPublication . Pina, S.; Carneiro, A.; Rodrigues, T.; Samões, R.; Taipa, R.; Melo-Pires, M.; Pereira, C.Glioblastoma is a malignant infiltrative glial tumor occurring most often over 50 years of age, with diverse clinical presentations. We describe a case of temporal lobe glioblastoma with a rare presentation as an acute ischemic stroke, discussing the imaging and histopathological findings, and reviewing the literature. A 77-year-old woman had sudden onset of left hemiparesis and hemihypoesthesia. The neuroradiological studies revealed an acute ischemic lesion in the right lenticulostriate arteries territory and a right anterior temporal lobe tumor, enhancing heterogeneously after contrast with enhancement of the right middle cerebral artery wall. Histopathological analysis of the resected temporal lesion revealed a glioblastoma multiforme with tumoral infiltration of the vascular wall. Glioblastoma should be considered in the etiology of acute ischemic stroke, where neuroimaging plays an important diagnostic role, enabling a more immediate therapeutic approach, with a consequent impact on survival.
- Hansen Neuropathy: Still a Possible Diagnosis in the Investigation of a Peripheral NeuropathyPublication . Veiga, A.; Costa, A.; Taipa, Ri.; Guimarães, A.; Melo-Pires, M.INTRODUCTION: Leprosy is still one of the most frequent causes of peripheral neuropathy. Although regarded as eradicated in Portugal, is still documented in neuropathological study of patients with clinical peripheral neuropathy without proper diagnosis.
- Nonprimary Cytomegalovirus Fetal InfectionPublication . Rodrigues, S.; Gonçalves, D.; Taipa, R.; Rodrigues, M.Cytomegalovirus (CMV) is the most common congenital viral infection, causing hearing, visual and psychomotor impairment. Preexisting maternal CMV immunity substantially reduces, but not eliminates, the risk of fetal infection and affectation. This article is about a case of nonprimary maternal CMV infection during pregnancy, with vertical transmission, resulting in severe fetal affectation. Preconceptional analysis indicated maternal CMV past infection. Pregnancy progressed uneventfully until the 20th week ultrasound (US), which revealed cerebral abnormalities: thin and hyperechogenic cerebral cortex with prominent lateral ventricles, bilateral periventricular hyperechogenicities, cerebellar vermis hypoplasia and absent corpus callosum. The MRI suggested these findings were compatible with congenital infection rather than primary brain malformation.The fetal karyotype was normal. The title of CMV's IgG antibodies almost tripled. Since the first semester, analysis of the polymerase chain reaction (PCR) for CMV DNA in the amniotic fluid was negative. The pregnancy was terminated at 23 weeks. Neuropathological findings at autopsy showed severe brain lesions associated with CMV infection.
- Hypoxia-mediated upregulation of MCT1 expression supports the glycolytic phenotype of glioblastomasPublication . Miranda-Gonçalves, V.; Granja, S.; Martinho, O.; Honavar, M.; Pojo, M.; Costa, B.; Melo-Pires, M.; Pinheiro, C.; Cordeiro, M.; Bebiano, G.; Costa, P.; Reis, R.; Baltazar, F.BACKGROUND: Glioblastomas (GBM) present a high cellular heterogeneity with conspicuous necrotic regions associated with hypoxia, which is related to tumor aggressiveness. GBM tumors exhibit high glycolytic metabolism with increased lactate production that is extruded to the tumor microenvironment through monocarboxylate transporters (MCTs). While hypoxia-mediated regulation of MCT4 has been characterized, the role of MCT1 is still controversial. Thus, we aimed to understand the role of hypoxia in the regulation of MCT expression and function in GBM, MCT1 in particular. METHODS: Expression of hypoxia- and glycolytic-related markers, as well as MCT1 and MCT4 isoforms was assessed in in vitro and in vivo orthotopic glioma models, and also in human GBM tissues by immunofluorescence/immunohistochemistry and Western blot. Following MCT1 inhibition, either pharmacologically with CHC (α-cyano-4-hydroxynnamic acid) or genetically with siRNAs, we assessed GBM cell viability, proliferation, metabolism, migration and invasion, under normoxia and hypoxia conditions. RESULTS: Hypoxia induced an increase in MCT1 plasma membrane expression in glioma cells, both in in vitro and in vivo models. Additionally, treatment with CHC and downregulation of MCT1 in glioma cells decreased lactate production, cell proliferation and invasion under hypoxia. Moreover, in the in vivo orthotopic model and in human GBM tissues, there was extensive co-expression of MCT1, but not MCT4, with the GBM hypoxia marker CAIX. CONCLUSION: Hypoxia-induced MCT1 supports GBM glycolytic phenotype, being responsible for lactate efflux and an important mediator of cell survival and aggressiveness. Therefore, MCT1 constitutes a promising therapeutic target in GBM.
- Post-mortem assessment in vascular dementia: advances and aspirationsPublication . McAleese, K.; Alafuzoff, I.; Charidimou, A.; De Reuck, J.; Grinberg, L.; Hainsworth, A.; Hortobagyi, T.; Ince, P.; Jellinger, K.; Gao, J.; Kalaria, R.; Kovacs, G.; Kövari, E.; Love, S.; Popovic, M.; Skrobot, O.; Taipa, R.; Thal, D.; Werring, D.; Wharton, S.; Attems, J.Background Cerebrovascular lesions are a frequent finding in the elderly population. However, the impact of these lesions on cognitive performance, the prevalence of vascular dementia, and the pathophysiology behind characteristic in vivo imaging findings are subject to controversy. Moreover, there are no standardised criteria for the neuropathological assessment of cerebrovascular disease or its related lesions in human post-mortem brains, and conventional histological techniques may indeed be insufficient to fully reflect the consequences of cerebrovascular disease. Discussion Here, we review and discuss both the neuropathological and in vivo imaging characteristics of cerebrovascular disease, prevalence rates of vascular dementia, and clinico-pathological correlations. We also discuss the frequent comorbidity of cerebrovascular pathology and Alzheimer’s disease pathology, as well as the difficult and controversial issue of clinically differentiating between Alzheimer’s disease, vascular dementia and mixed Alzheimer’s disease/vascular dementia. Finally, we consider additional novel approaches to complement and enhance current post-mortem assessment of cerebral human tissue. Conclusion Elucidation of the pathophysiology of cerebrovascular disease, clarification of characteristic findings of in vivo imaging and knowledge about the impact of combined pathologies are needed to improve the diagnostic accuracy of clinical diagnoses.
- Exonization of an Intronic LINE-1 Element Causing Becker Muscular Dystrophy as a Novel Mutational Mechanism in Dystrophin GenePublication . Gonçalves, A.; Oliveira, J.; Coelho, T.; Taipa, R.; Melo-Pires, M.; Sousa, M.; Santos, R.A broad mutational spectrum in the dystrophin (DMD) gene, from large deletions/duplications to point mutations, causes Duchenne/Becker muscular dystrophy (D/BMD). Comprehensive genotyping is particularly relevant considering the mutation-centered therapies for dystrophinopathies. We report the genetic characterization of a patient with disease onset at age 13 years, elevated creatine kinase levels and reduced dystrophin labeling, where multiplex-ligation probe amplification (MLPA) and genomic sequencing failed to detect pathogenic variants. Bioinformatic, transcriptomic (real time PCR, RT-PCR), and genomic approaches (Southern blot, long-range PCR, and single molecule real-time sequencing) were used to characterize the mutation. An aberrant transcript was identified, containing a 103-nucleotide insertion between exons 51 and 52, with no similarity with the DMD gene. This corresponded to the partial exonization of a long interspersed nuclear element (LINE-1), disrupting the open reading frame. Further characterization identified a complete LINE-1 (~6 kb with typical hallmarks) deeply inserted in intron 51. Haplotyping and segregation analysis demonstrated that the mutation had a de novo origin. Besides underscoring the importance of mRNA studies in genetically unsolved cases, this is the first report of a disease-causing fully intronic LINE-1 element in DMD, adding to the diversity of mutational events that give rise to D/BMD.
- WNT6 is a novel oncogenic prognostic biomarker in human glioblastomaPublication . Gonçalves, C.; Vieira de Castro, J.; Pojo, M.; Martins, E.; Queirós, S.; Chautard, E.; Taipa, Ricardo; Pires, M.; Pinto, A.; Pardal, F.; Custódia, C.; Faria, C.; Clara, C.; Reis, R.; Sousa, N.; Costa, B.Glioblastoma (GBM) is a universally fatal brain cancer, for which novel therapies targeting specific underlying oncogenic events are urgently needed. While the WNT pathway has been shown to be frequently activated in GBM, constituting a potential therapeutic target, the relevance of WNT6, an activator of this pathway, remains unknown. Methods: WNT6 protein and mRNA levels were evaluated in GBM. WNT6 levels were silenced or overexpressed in GBM cells to assess functional effects in vitro and in vivo. Phospho-kinase arrays and TCF/LEF reporter assays were used to identify WNT6-signaling pathways, and significant associations with stem cell features and cancer-related pathways were validated in patients. Survival analyses were performed with Cox regression and Log-rank tests. Meta-analyses were used to calculate the estimated pooled effect. Results: We show that WNT6 is significantly overexpressed in GBMs, as compared to lower-grade gliomas and normal brain, at mRNA and protein levels. Functionally, WNT6 increases typical oncogenic activities in GBM cells, including viability, proliferation, glioma stem cell capacity, invasion, migration, and resistance to temozolomide chemotherapy. Concordantly, in in vivo orthotopic GBM mice models, using both overexpressing and silencing models, WNT6 expression was associated with shorter overall survival, and increased features of tumor aggressiveness. Mechanistically, WNT6 contributes to activate typical oncogenic pathways, including Src and STAT, which intertwined with the WNT pathway may be critical effectors of WNT6-associated aggressiveness in GBM. Clinically, we establish WNT6 as an independent prognostic biomarker of shorter survival in GBM patients from several independent cohorts. Conclusion: Our findings establish WNT6 as a novel oncogene in GBM, opening opportunities to develop more rational therapies to treat this highly aggressive tumor.
- Leprosy presenting as remitting seronegative symmetrical synovitis with pitting oedema syndrome - a case reportPublication . Guerra, M.; Videira, T.; Morais, H.; Santos, T.; Taipa, Ricardo; Abreu, M.; Vieira; da Fonseca; Dos Santos; PintoBackground: Leprosy typically manifests with skin and peripheral nerve involvement. Musculoskeletal complaints are the third most common, and can be the sole presenting manifestation. They range from arthralgia/arthritis in reactional states to full mimics of systemic rheumatic diseases. Remitting Seronegative Symmetrical Synovitis with Pitting Oedema syndrome has only been described once in a patient with already diagnosed Leprosy. Case report: A 68-year-old male, from an endemic region of familial amyloid polyneuropathy, presented with an inaugural Remitting Seronegative Symmetrical Synovitis with Pitting Oedema like syndrome, more that 20 years after travelling to Leprosy endemic areas. Arthritis would resurface whenever oral prednisone was tapered, so methotrexate was started, controlling the complaints. Only one year later, after the appearance of peripheral neuropathy and skin lesions, it was possible to diagnose Leprosy, through the identification of Mycobacterium leprae bacilli in a peripheral nerve biopsy. Conclusion: This report is an example of the heterogeneity of manifestations of Leprosy, namely rheumatic, and the challenge of diagnosing it when typical complaints are absent. It is also a reminder that this disease should be considered whenever a patient with a combination of skin/neurologic/rheumatic complaints has travelled to endemic countries in the past.
- A novel molecular link between HOXA9 and WNT6 in glioblastoma identifies a subgroup of patients with particular poor prognosisPublication . Gonçalves, Céline S.; Xavier‐Magalhães, Ana; Martins, Eduarda P.; Pinto, Afonso A.; Pires, Manuel; Pinheiro, Célia; Reis, Rui M.; Sousa, Nuno; Costa, Bruno M.Despite much effort to improve treatments, patients with malignant glioma still present a very poor prognosis that has not changed significantly in the last decades. In this context, it is crucial to better understand glioma pathogenesis to identify new molecular prognostic subgroups and therapeutic targets. WNT6 was recently identified as a new oncogenic molecule in glioblastoma (GBM), with prognostic value in patients, but the mechanisms underlying WNT6 aberrant expression in glioma are still unknown. WNT6 was overexpressed in a subset of gliomas independently of IDH mutations, 1p/19q codeletion status, and WNT6 gene copy number. Interestingly, WNT6 expression is associated with the DNA methylation levels of particular CpG regions at both the WNT6 promoter and the gene body in glioma patient samples. HOXA9, a transcription factor previously associated with poorer clinical outcome in GBM, was identified as a novel transcriptional regulator of WNT6, activating the WNT/β-catenin pathway in vitro and in vivo. In various cohorts of glioma patients, mRNA levels of WNT6 and HOXA9 were significantly correlated, extending our in vitro and in vivo findings into the clinical setting. Interestingly, this novel molecular link between WNT6 and HOXA9 was not limited to glioma, as they were co-expressed also in patients with other tumor types. Clinically, WNT6 was a prognostic biomarker of shorter survival in GBM, independently of HOXA9 expression. Concomitant high expression of both WNT6 and HOXA9 identified a subgroup of patients with particularly dismal survival. These findings describe novel WNT6 regulatory mechanisms in GBM, establishing particular DNA methylation patterns and HOXA9 as critical regulators of WNT6 expression in glioma. This HOXA9-WNT6 molecular link supports WNT signaling in GBM cells and is a powerful prognostic biomarker, highlighting the clinical relevance of this axis in patients. Novel therapies targeting WNT6-HOXA9 signaling may thus be useful for this deadly disease.