Browsing by Author "Leal, B."
Now showing 1 - 10 of 15
Results Per Page
Sort Options
- APOE isoforms in focal epilepsies: an association study in a Portuguese populationPublication . Martins da Silva, A.; Leal, B.; Chaves, J.; Carvalho, C.; Bettencourt, A.; Branco, R.C.; Ferreira, J.; Costa, P.; Martins da Silva, B.Purpose: Apolipoprotein E (ApoE) is the main lipoprotein secreted in brain. It has a critical immuno-modulatory function, influences neurotransmission and is involved in repairing damaged neurons. ApoE e4 allele is an isoform of ApoE with altered protein function previously associated with refractoriness and early onset epilepsy. Our purpose was to investigate if apoE isoforms are risk factors for partial epilepsy and to correlate genotypes with anti-epileptic drug response. Methods: A cohort of 230 epileptic patients with partial epilepsies from the outpatient clinic at HSA-CHP [109F, 121M; mean age = 44 13 years, age of onset = 15 13 years; 168 patients with Drug Refractory Epilepsy (DRE)] was compared with a cohort of 301 healthy individuals (HI) in a case control study. ApoE isoforms were genotype by RFLP-PCR methodology. Results: ApoE e4 allele frequency was higher in epileptic group when compared with HI (10.6% vs. 7.6%, p = n.s., OR = 1.44, 95% CI: 0.945–2.20). Anti-epileptic Drug response was not influenced by apoE isoforms. Conclusion: Our results suggest that ApoE e4 may be a risk factor for partial epilepsy development. ApoE e4 is associated with CNS network instability, with lower protection against oxidative and inflammatory cascade. These could influence neuronal growth and recovery leading to a chronic vicious cycle of damage and neuronal loss contributing to seizures development. These observations should be confirmed in a larger cohort.
- Apoe isoforms in patients with psoriasisPublication . Ferreira, J.C.P.; Torres, T.; Carvalho, C.A.; Bettencourt, A.; Leal, B.; Vasconcelos, C.; Costa, P.P.; Selores, M.; Silva, B.M.Introduction: Psoriasis is a chronic inflammatory skin disease affecting 2–3% of the world population. Patients with psoriasis (Ps) have higher prevalence of lipid disorders when compared to unaffected individuals. These patients, especially those with severe and prolonged disease, have an increased morbidity and mortality from cardiovascular events. Apolipoprotein E (ApoE), a protein involved in lipid metabolism, cholesterol and phospholipid transport, has functionally relevant gene variants. It has been described that the e4 allele may increase the risk to develop atherosclerosis, and the e2 allele has been associated with hyperlipoproteinemia type III. An increased risk of psoriasis among persons with these two alleles has also been reported. Nevertheless, the role of ApoE in Psoriasis remains controversial. Objectives: The aim of this work was to investigate the relationship between APOE-e2/e3/e4 variants and psoriasis in a Portuguese population. Materials and Methods: A cohort of 178 unrelated (74 females, 104 males) severe psoriatic patients [according to the Psoriasis Area and Severity Index (PASI)] from Centro Hospitalar do Porto/Hospital de Santo Ant onio and 285 ethnically-matched healthy controls were studied. Genotyping of APOE was performed using a Polymerase chain reaction restriction fragment-length polymorphism (PCR-RFLP) assay. Results: The frequency of the e4 allele was significantly higher in patients than in controls [(11.5% vs. 7.6%), p = 0.044, OR=1.57 (1.01–2.45)]. Conclusion: The ApoE e4 isoform could be a risk factor for psoriatic disease in this population. Our result is in agreement with previous studies in a Spanish population that associated the e4 isoform with severe psoriasis. These results support the hypothesis that ApoE has a modulatory role in inflammatory conditions.
- Association between vitamin D receptor (VDR) gene polymorphisms and systemic lupus erythematosus in Portuguese patientsPublication . Carvalho, C.; Marinho, A.; Leal, B.; Bettencourt, A.; Boleixa, D.; Almeida, I.; Farinha, F.; Costa, P.P.; Vasconcelos, C.; Silva, B.M.Systemic lupus erythematosus (SLE) is a chronic autoimmune disease of unknown origin, in which both genetic and environmental factors are involved. One such environmental factor is vitamin D, a vital hormone that plays a specific function in the immune system homeostasis, acting through a nuclear receptor (VDR) expressed in all immune cells. Several polymorphisms of the gene that encodes this receptor have been described. Though inconsistently, these polymorphisms have been associated with clinical manifestations and SLE development.The aim of this study was to determine the possible association between VDR gene polymorphisms (BsmI, ApaI, TaqI e FokI) and SLE susceptibility and severity, in a cohort of lupus patients from the north of Portugal.A total of 170 patients (F = 155, M = 15; age = 45 ± 13.4 years) with SLE (diagnosed according the American College of Rheumatology criteria) with at least five years of disease evolution and followed in the Autoimmune Disease Clinical Immunology Unit of Centro Hospitalar do Porto were studied. Patients and 192 ethnicity-matched controls were genotyped for BsmI (rs1544410), ApaI (rs7975232), TaqI (rs731236) and FokI (rs2228570) polymorphisms by TaqMan allelic discrimination assay. Disease severity was assessed by SLICC damage score, number of affected organs, number of severe flares and pharmacological history.SLE patients with the CT genotype of FokI polymorphism have a higher SLICC value (p = 0.031). The same result was observed for the group of patients with the TT genotype of TaqI polymorphism (p = 0.046). No differences were observed in VDR genotype between patients and controls. Also, we observed that the other clinical features analysed were not influenced by VDR polymorphisms.Our study confirms a possible role of VDR gene polymorphisms in SLE. A positive association was found between VDR polymorphisms and SLE severity (chronic damage). The presence of CT genotype of FokI and TT genotype of TaqI seems to confer a worse prognosis and may constitute a risk factor for higher long-term cumulative damage in SLE patients.
- CCR5-Delta32: Implications in SLE developmentPublication . Carvalho, C.; Calvisi, S.L.; Leal, B.; Bettencourt, A.; Marinho, A.; Almeida, I.; Farinha, F.; Pinho-Costa, P.; Silva, B.M.; Vasconcelos, C.Systemic lupus erythematosus (SLE) is a prototypical autoimmune disease with strong genetic and environmental components. Previous studies have shown increased levels of several chemokines in active SLE. C-C chemokine receptor type 5 (CCR5) is involved in the recruitment of inflammatory cells into tissues, and mechanisms modulating CCR5 expression and function may interfere in SLE development, influencing the clinical course of the disease. The aim of this study was to evaluate the possible association between the CCR5{increment}32 base-pair deletion polymorphism and SLE disease in a group of Portuguese patients. A total of 219 patients with SLE and 205 healthy individuals were studied. The frequency of CCR5[del]32 heterozygotes was lower in patients with SLE than in controls (8% vs. 15% OR = 0.5162; P = 0.0319), suggesting a protective association between CCR5[del]32 allele and SLE. These results highlight the protective role of Th1 cells that express CCR5 in SLE pathogenesis.
- Circulating microRNAs as potential biomarkers for genetic generalized epilepsies: a three microRNA panelPublication . Martins‐Ferreira, R.; Chaves, J.; Carvalho, C.; Bettencourt, A.; Chorão, R.; Freitas, J.; Samões, R.; Boleixa, D.; Lopes, J.; Ramalheira, J.; Silva, B.M.; Martins da Silva, A.; Costa, P. P.; Leal, B.Background and purpose: Genetic generalized epilepsies (GGEs) encompass a group of syndromes of mainly genetic causes, characterized by the involvement of both hemispheres. MicroRNAs (miRNAs) are small non-coding RNAs with a critical role in the regulation of neuronal biological processes through gene expression modulation. Dysregulated miRNA expression has been shown in epilepsy. Due to their stability in biological fluids like serum, miRNAs have assumed a prominent role in biomarker research. Our aim was to evaluate circulating levels of three miRNAs in GGE patients and assess their putative diagnostic value. Methods: MiR-146a, miR-155 and miR-132 were quantified by real-time polymerase chain reaction in the serum of 79 GGE patients (47 women, 32 men, 35.1 ± 12.4 years) and 67 healthy individuals (41 women, 26 men, 42.4 ± 10.1 years). Relative expression values were calculated using the 2-ΔΔCt method. Receiver operating characteristic curve analysis was performed to assess diagnostic value. MiRNA expression was correlated with clinicopathological features. Results: Serum levels of miR-146a and miR-155 were significantly upregulated in GGE patients relative to controls (3.13 and 6.05, respectively). Combined miR-146a, miR-155 and miR-132 serum levels performed well as a diagnostic biomarker, discriminating GGE patients from controls with an area under the curve of 0.85, 80% specificity and 73% sensitivity. Conclusions: Our results indicate that miR-146a, miR-155 and miR-132 may partake in GGE epileptogenesis. A panel of three circulating miRNAs with potential value as a GGE biomarker is reported for the first time. Novel biomarkers may help to identify new treatment targets and contribute to improved patients' quality of life through earlier diagnosis and a more precise prognosis.
- Epilepsy, hippocampal sclerosis and febrile seizures linked by common genetic variation around SCN1APublication . Kasperavičiute, D.; Catarino, C.B.; Matarin, M.; Leu, C.; Novy, J.; Tostevin, A.; Leal, B.; Hessel, E.V.S.; Hallmann, K.; Hildebrand, M.S.; Dahl, H-H.M.; Ryten, M.; Trabzuni, D.; Ramasamy, A.; Alhusaini, S.; Doherty, C.P.; Dorn, T.; Hansen, J.; Krämer, G.; Steinhoff, B.J.; Zumsteg, D.; Duncan, S.; Kälviäinen, R.K.; Eriksson, K.J.; Kantanen, A-M; Pandolfo, M.; Gruber-Sedlmayr, U.; Schlachter, K.; Reinthaler, E.M.; Stogmann, E.; Zimprich, F.; Theatre, E.; Smith, C.; Obrien, T.J.; Tan, K.M.; Petrovski, S.; Robbiano, A.; Paravidino, R.; Zara, F.; Striano, P.; Sperling, M.R.; Buono, R.J.; Hakonarson, H.; Chaves, J.; Costa, P.P.; Silva, B.M.; Da Silva, A.M.; De Graan, P.N.E.; Koeleman, B.P.C.; Becker, A.; Schoch, S.; Von Lehe, M.; Reif, P.S.; Rosenow, F.; Becker, F.; Weber, Y.; Lerche, H.; Roessler, K.; Buchfelder, M.; Hamer, H.M.; Kobow, K.; Coras, R.; Blumcke, I.; Scheffer, I.E.; Berkovic, S.F.; Weale, M.E.; Delanty, N.; Depondt, C.; Cavalleri, G.L.; Kunz, W.S.; Sisodiya, S.M.Epilepsy comprises several syndromes, amongst the most common being mesial temporal lobe epilepsy with hippocampal sclerosis. Seizures in mesial temporal lobe epilepsy with hippocampal sclerosis are typically drug-resistant, and mesial temporal lobe epilepsy with hippocampal sclerosis is frequently associated with important co-morbidities, mandating the search for better understanding and treatment. The cause of mesial temporal lobe epilepsy with hippocampal sclerosis is unknown, but there is an association with childhood febrile seizures. Several rarer epilepsies featuring febrile seizures are caused by mutations in SCN1A, which encodes a brain-expressed sodium channel subunit targeted by many anti-epileptic drugs. We undertook a genome-wide association study in 1018 people with mesial temporal lobe epilepsy with hippocampal sclerosis and 7552 control subjects, with validation in an independent sample set comprising 959 people with mesial temporal lobe epilepsy with hippocampal sclerosis and 3591 control subjects. To dissect out variants related to a history of febrile seizures, we tested cases with mesial temporal lobe epilepsy with hippocampal sclerosis with (overall n = 757) and without (overall n = 803) a history of febrile seizures. Meta-analysis revealed a genome-wide significant association for mesial temporal lobe epilepsy with hippocampal sclerosis with febrile seizures at the sodium channel gene cluster on chromosome 2q24.3 [rs7587026, within an intron of the SCN1A gene, P = 3.36 × 10(-9), odds ratio (A) = 1.42, 95% confidence interval: 1.26-1.59]. In a cohort of 172 individuals with febrile seizures, who did not develop epilepsy during prospective follow-up to age 13 years, and 6456 controls, no association was found for rs7587026 and febrile seizures. These findings suggest SCN1A involvement in a common epilepsy syndrome, give new direction to biological understanding of mesial temporal lobe epilepsy with hippocampal sclerosis with febrile seizures, and open avenues for investigation of prognostic factors and possible prevention of epilepsy in some children with febrile seizures.
- Expression of adenosine kinase in human mesial temporal lobe epilepsy with hippocampal sclerosis: A preliminary studyPublication . Leal, B.; Rangel, R.; Chaves, J.; Carvalho, C.; Bettencourt, A.; Zenatti, L.; Santos, A.; Magalhães, T.; Martins da Silva, A.; Correia de Sá, P.; Martins da Silva, B.; Costa, P.P.Background: Adenosine is a ubiquitous homeostatic molecule that acts as an “endogenous neuromodulator”. Adenosine attenuates neuronal activity either presynaptically by inhibiting neurotransmitter release or by controlling neurotransmitter responsiveness at post-synaptic sites. Unbalanced adenosine metabolism has been implicated in pathological conditions such as epilepsy. Adenosine kinase (ADK), synthetized by astrocytes, is the key regulator of extracellular adenosine levels in the brain. Evidences from experimental studies support a role for ADK in brain injury associated with astrogliosis, a morphological hallmark of Mesial Temporal Lobe Epilepsy with Hippocampal Sclerosis (MTLE-HS). In fact, expression of astrocytic ADK was found to be increased in the hippocampus and temporal cortex of MTLE-HS patients. Overexpression of ADK decreases extracellular adenosine and consequently may cause seizures. The aim of this study was to characterize ADK gene expression in MTLE-HS patients. Methods: Previous studies used immunohistochemistry and Western blot analysis to investigate ADK expression. Here we quantified the expression levels of ADK by Real-Time PCR in the hippocampus (lesional and peri-lesional cortical area) of 10 MTLE-HS patients submitted to surgery as compared with 9 autopsy controls with no history of neurological disorders. Results: Our results showed that ADK expression levels were similar in the hippocampus and temporal cortex of MTLE-HS patients when compared to healthy controls. Conclusion: Our preliminary data demonstrate that ADK expression levels are not altered in MTLE-HS. These results do not preclude post-transcriptional ADK abnormalities at both protein and functional levels. Our results should be confirmed in a larger cohort as well as with complementary methodologies.
- Expression of miR146-a, an inflammation-associated microRNA, in Mesial Temporal Lobe EpilepsyPublication . Leal, B.; Carvalho, C.; Chaves, J.; Bettencourt, A.; Freitas, J.; Lopes, J.; Ramalheira, J.; Martins da Silva, A.; Costa, P. P.; Martins da Silva, B.Background: Neuroinflammation appears as an important epileptogenic mechanism. MicroRNAs (miRNA) are small non-coding RNA molecules that function as post-transcriptional regulators of gene expression. MicroRNas control different biological process including immune system homeostasis and function. Several evidences, both in patients and animal studies, have demonstrated an abnormal brain expression of miR-146a in Mesial Temporal Lobe Epilepsy. Knowing that miR expression is very stable in biological fluids such as plasma or serum our aim was to characterize miR146a expression in serum of MTLE patients. Methods: Expression levels of miR146a and U6B small nuclear RNA gene (reference gene) were quantified by Real-Time PCR in serum of 14 MTLE patients all with Hippocampal Sclerosis (6F, 8M, mean age= 44.1±11.7 years, age of onset= 13.5±10.6 years, 7 with Febrile Seizures antecedents). A group of 10 healthy individuals was used as control. Relative expression values were calculated using the 2-ΔΔCt method. Results: We observed that expression of miR146a was 2 fold higher in MTLE-HS patients than in controls. Conclusion: The results obtained in serum are in accordance with the results obtained from brain tissue of epileptic patients. This may confirm that miR-146a is a suitable biomarker of epileptogenesis. Additionally, it is thought that miR-146a has a role in fine-tuning the response to cytokines during epileptogenesis. Nevertheless its importance in epilepsy development it is yet not fully understood. The comprehension of this role may be relevant for the development of new therapeutic strategies.
- Human herpes virus 6B and mesial temporal lobe epilepsy with hippocampal sclerosis (MTLE-HS): is there a link?Publication . Leal, B.; Castelo Branco, R.; Rangel, R.; Chaves, J.; Carvalho, C.; Bettencourt, A.; Honavar, M.; Melo Pires, M.; Santos, A.; Magalhães, T.; Lopes, J.; Ramalheira, J.; Martins da Silva, A.; Costa, P.P.; Martins da Silva, B.Purpose: Human Herpesvirus 6 (HHV-6) is a ubiquitous virus acquired mainly during the first 2 years of life. Mesial Temporal Lobe Epilepsy with Hippocampal Sclerosis (MTLE-HS) is the most frequent pharmacoresistant epilepsy. One of the most common antecedents of MTLE-HS is febrile seizures (FS). Although the aetiology of MTLE-HS remains unclear, evidences suggest that HHV-6 infection could be implicated. The objective of this study was to investigate the presence of HHV-6B DNA in the hippocampus and adjoining temporal cortex of MTLE-HS patients submitted to surgery. Methods: A total of 22 MTLE-HS (13 females and nine males) cases were studied. The mean age at surgery was 39 9 years and mean age at onset of seizures was 10 6 years. These study cohort was compared to a group of 10 epileptic patients without MTLE-HS (six females, four males; mean age = 26 15 years) and with autopsy material from nine individuals without neurological disease. HHV-6B DNA was identified by real-time PCR with specific TaqMan probes. Results: We detected HHV-6B DNA in only one hippocampus from a MTLE-HS patient. This patient had a disease duration of 36 years and a history of febrile seizures in childhood. None of the non-MTLE or controls specimens showed positivity for HHV-6B. Conclusions: Our findings do not support a relevant etiologic role for HHV-6B in MTLE-HS, at least in this population. However, the possible role of viral infection in MTLE-HS epileptogenic process, in individual cases, cannot be excluded.
- IL-6 and TNF-alpha polymorphisms in portuguese psoriatic patientsPublication . Ferreira, J.P.; Torres, T.; Carvalho, C.; Bettencourt, A.; Leal, B.; Vasconcelos, C.; Costa, P.P.; Selores, M.; Silva, B.M.Introduction: Cytokines regulate the growth, function and differentiation of cells and help to steer immune response and inflammation. In this study we focused our attention in two proinflammatory cytokines: IL-6 and TNFa. It is known that their overexpression is responsible for initiation, maintenance and recurrence of skin lesions in psoriatic patients. Therefore, it is important to investigate genetic biomarkers with functional effects in the genes of those cytokines that could help to predict the severity of Psoriasis. Objectives: To investigate the hypothesis that allelic variants in IL-6 and TNF-a genes are a risk factor for the developing of severe Psoriasis. Materials and Methods: A cohort of 178 (74 females, 104 males) psoriatic patients with severe plaque type psoriasis [according to the Psoriasis Area and Severity Index (PASI)] and 206 healthy individuals were selected. Several polymorphisms in the IL-6 gene (rs1800795, rs1800796, rs2069827, rs2069840) and TNF-a (rs361525, rs1799964, rs1800629) promoter region were genotyped. SNP genotyping was performed using Mass Spectrometry (MassARRAY iPLEX–Sequenom). Results: We observed a lower frequency in the minor allele (C) of the TNFa rs1799964 SNP in psoriatic patients, compared with controls [(21.9% vs. 29.4%), p = 0.02, OR = 0.675 (0.49–0.94)]. The frequency of the CC genotype in patients was 3.93% while in the healthy control group it was 9.22% [(p = 0.04, OR = 0.403 (0.17–0.98)]. No statistical significant differences were found in the other polymorphisms. Conclusion: Our data suggest that the rs1799964 C allele could be a protective factor for developing severe psoriasis. These results were similar to the findings of Gallo et al (2012) in a Spanish population. The mechanism to explain this association remains elusive, given the lack of evidence of a functional association.