Percorrer por autor "Pereira, Isabel"
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- Avaliação da Frequência de Microdelecções AZF e alterações do cariótipo na OligospermiaPublication . Pereira, Isabel; Barros, Joana; Aguiar, Ana; Sousa, Sandra; Nunes, Joaquim; Rodrigues, Cátia; Soares, Ana Paula; Pereira-Caetano, Iris; Gonçalves, João; Calhaz Jorge, CarlosA infertilidade masculina é uma entidade complexa que afecta um número importante de homens, permanecendo a sua etiologia desconhecida em muitas situações. Alterações do cariótipo podem contribuir para diminuir a quantidade e qualidade dos espermatozóides. A elucidação de eventual base genética subjacente pode ajudar a determinar a razão da alteração espermática e abrir novas perspectivas para tratamentos eficazes. A região AZF (azoospermia factor) do cromossoma Y contém genes essenciais para a espermatogénese.
- Common Variation in the PIN1 Locus Increases the Genetic Risk to Suffer from Sertoli Cell-Only SyndromePublication . Cerván-Martín, Miriam; Bossini-Castillo, Lara; Guzmán-Jimenez, Andrea; Rivera-Egea, Rocío; Garrido, Nicolás; Luján, Saturnino; Romeu, Gema; Santos-Ribeiro, Samuel; Castilla, José A.; Gonzalvo, M. Carmen; Clavero, Ana; Vicente, F. Javier; Maldonado, Vicente; González-Muñoz, Sara; Rodríguez-Martín, Inmaculada; Burgos, Miguel; Jiménez, Rafael; Pinto, Maria Graça; Pereira, Isabel; Nunes, Joaquim; Sánchez-Curbelo, Josvany; López-Rodrigo, Olga; Pereira-Caetano, Iris; Marques, Patricia Isabel; Carvalho, Filipa; Barros, Alberto; Bassas, Lluís; Seixas, Susana; Gonçalves, João; Larriba, Sara; Lopes, Alexandra M.; Carmona, F. David; Palomino-Morales, Rogelio J.We aimed to analyze the role of the common genetic variants located in the PIN1 locus, a relevant prolyl isomerase required to control the proliferation of spermatogonial stem cells and the integrity of the blood-testis barrier, in the genetic risk of developing male infertility due to a severe spermatogenic failure (SPGF). Genotyping was performed using TaqMan genotyping assays for three PIN1 taggers (rs2287839, rs2233678 and rs62105751). The study cohort included 715 males diagnosed with SPGF and classified as suffering from non-obstructive azoospermia (NOA, n = 505) or severe oligospermia (SO, n = 210), and 1058 controls from the Iberian Peninsula. The allelic frequency differences between cases and controls were analyzed by the means of logistic regression models. A subtype specific genetic association with the subset of NOA patients classified as suffering from the Sertoli cell-only (SCO) syndrome was observed with the minor alleles showing strong risk effects for this subset (ORaddrs2287839 = 1.85 (1.17-2.93), ORaddrs2233678 = 1.62 (1.11-2.36), ORaddrs62105751 = 1.43 (1.06-1.93)). The causal variants were predicted to affect the binding of key transcription factors and to produce an altered PIN1 gene expression and isoform balance. In conclusion, common non-coding single-nucleotide polymorphisms located in PIN1 increase the genetic risk to develop SCO.
- Contribution of TEX15 genetic variants to the risk of developing severe non-obstructive oligozoospermiaPublication . Guzmán-Jiménez, Andrea; González-Muñoz, Sara; Cerván-Martín, Miriam; Rivera-Egea, Rocío; Garrido, Nicolás; Luján, Saturnino; Santos-Ribeiro, Samuel; Castilla, José A.; Gonzalvo, M. Carmen; Clavero, Ana; Vicente, F. Javier; Maldonado, Vicente; Villegas-Salmerón, Javier; Burgos, Miguel; Jiménez, Rafael; Pinto, Maria Graça; Pereira, Isabel; Nunes, Joaquim; Sánchez-Curbelo, Josvany; López-Rodrigo, Olga; Pereira-Caetano, Iris; Marques, Patricia Isabel; Carvalho, Filipa; Barros, Alberto; Bassas, Lluís; Seixas, Susana; Gonçalves, João; Lopes, Alexandra M.; Larriba, Sara; Palomino-Morales, Rogelio J.; Carmona, F. David; Bossini-Castillo, LaraBackground: Severe spermatogenic failure (SPGF) represents one of the most relevant causes of male infertility. This pathological condition can lead to extreme abnormalities in the seminal sperm count, such as severe oligozoospermia (SO) or non-obstructive azoospermia (NOA). Most cases of SPGF have an unknown aetiology, and it is known that this idiopathic form of male infertility represents a complex condition. In this study, we aimed to evaluate whether common genetic variation in TEX15, which encodes a key player in spermatogenesis, is involved in the susceptibility to idiopathic SPGF. Materials and Methods: We designed a genetic association study comprising a total of 727 SPGF cases (including 527 NOA and 200 SO) and 1,058 unaffected men from the Iberian Peninsula. Following a tagging strategy, three tag single-nucleotide polymorphisms (SNPs) of TEX15 (rs1362912, rs323342, and rs323346) were selected for genotyping using TaqMan probes. Case-control association tests were then performed by logistic regression models. In silico analyses were also carried out to shed light into the putative functional implications of the studied variants. Results: A significant increase in TEX15-rs1362912 minor allele frequency (MAF) was observed in the group of SO patients (MAF = 0.0842) compared to either the control cohort (MAF = 0.0468, OR = 1.90, p = 7.47E-03) or the NOA group (MAF = 0.0472, OR = 1.83, p = 1.23E-02). The genotype distribution of the SO population was also different from those of both control (p = 1.14E-02) and NOA groups (p = 4.33–02). The analysis of functional annotations of the human genome suggested that the effect of the SO-associated TEX15 variants is likely exerted by alteration of the binding affinity of crucial transcription factors for spermatogenesis. Conclusion: Our results suggest that common variation in TEX15 is involved in the genetic predisposition to SO, thus supporting the notion of idiopathic SPGF as a complex trait.
- Immune and spermatogenesis-related loci are involved in the development of extreme patterns of male infertilityPublication . Cerván-Martín, Miriam; Tüttelmann, Frank; Lopes, Alexandra M.; Bossini-Castillo, Lara; Rivera-Egea, Rocío; Garrido, Nicolás; Lujan, Saturnino; Romeu, Gema; Santos-Ribeiro, Samuel; Castilla, José A.; Carmen Gonzalvo, M.; Clavero, Ana; Maldonado, Vicente; Vicente, F. Javier; González-Muñoz, Sara; Guzmán-Jiménez, Andrea; Burgos, Miguel; Jiménez, Rafael; Pacheco, Alberto; González, Cristina; Gómez, Susana; Amorós, David; Aguilar, Jesus; Quintana, Fernando; Calhaz-Jorge, Carlos; Aguiar, Ana; Nunes, Joaquim; Sousa, Sandra; Pereira, Isabel; Pinto, Maria Graça; Correia, Sónia; Sánchez-Curbelo, Josvany; López-Rodrigo, Olga; Martín, Javier; Pereira-Caetano, Iris; Marques, Patricia I.; Carvalho, Filipa; Barros, Alberto; Gromoll, Jörg; Bassas, Lluís; Seixas, Susana; Gonçalves, João; Larriba, Sara; Kliesch, Sabine; Palomino-Morales, Rogelio J.; Carmona, F. DavidWe conducted a genome-wide association study in a large population of infertile men due to unexplained spermatogenic failure (SPGF). More than seven million genetic variants were analysed in 1,274 SPGF cases and 1,951 unaffected controls from two independent European cohorts. Two genomic regions were associated with the most severe histological pattern of SPGF, defined by Sertoli cell-only (SCO) phenotype, namely the MHC class II gene HLA-DRB1 (rs1136759, P = 1.32E-08, OR = 1.80) and an upstream locus of VRK1 (rs115054029, P = 4.24E-08, OR = 3.14), which encodes a protein kinase involved in the regulation of spermatogenesis. The SCO-associated rs1136759 allele (G) determines a serine in the position 13 of the HLA-DRβ1 molecule located in the antigen-binding pocket. Overall, our data support the notion of unexplained SPGF as a complex trait influenced by common variation in the genome, with the SCO phenotype likely representing an immune-mediated condition.
- In vitro genotoxicity assessment of an oxidized dextrin-based hydrogel for biomedical applicationsPublication . Pereira, Isabel; Fraga, Sónia; Silva, Susana; Teixeira, João Paulo; Gama, MiguelHydrogels are three‐dimensional, crosslinked networks of hydrophilic polymers swollen with a large amount of water or biological fluids, without dissolving. Dextrin, a low‐molecular‐weight carbohydrate composed by glucose residues, has been used to develop an injectable hydrogel for biomedical applications. Dextrin was first oxidized to introduce aldehyde groups, which then reticulate with adipic acid dihydrazide, forming the dextrin‐based hydrogel (HG). The HG and its components were tested for cyto‐ and genotoxicity according to the International Standard ISO 10993‐3 on the biological evaluation of medical devices. To assess genotoxicity, a battery of in vitro genotoxicity tests employing both eukaryotic and prokaryotic models was performed: comet assay, cytokinesis‐block micronucleus assay and Ames test. Our data revealed that the HG (IC50 = 2.8 mg/mL) and oxidized dextrin by itself (IC50 = 1.2 mg/mL) caused a concentration‐dependent decrease in cellular viability of human lymphoblastoid TK6 cells after 24 hours of exposure to the test agents. However, these concentrations are unlikely to be reached in vivo. In addition, no significant increase in the DNA and chromosomal damage of TK6 cells exposed to non‐cytotoxic concentrations of the HG and its isolated components was detected. Furthermore, neither the HG nor its metabolites exerted a mutagenic effect in different of Salmonella typhimurium strains and in an Escherichia coli mix. Our data demonstrated the genocompatibility of the HG (up to 3.5 mg/mL) for biomedical applications. To our best acknowledge, this is the first report with a detailed genotoxicity assessment of an aldehyde‐modified polysaccharide/adipic acid dihydrazide hydrogel.
- In vivo systemic toxicity assessment of an oxidized dextrin‐based hydrogel and its effectiveness as a carrier and stabilizer of granular synthetic bone substitutesPublication . Pereira, Isabel; Fraga, Sónia; Maltez, Luís; Requicha, João; Guardão, Luísa; Oliveira, Joana; Prada, Justina; Alves, Helena; Santos, José Domingos; Teixeira, João Paulo; Pereira, José Eduardo; Soares, Raquel; Gama, Francisco MiguelThe worldwide incidence of bone disorders is raising, mainly due to aging population. The lack of effective treatments is pushing the development of synthetic bone substitutes (SBSs). Most ceramic-based SBSs commercially available display limited handling properties. Attempting to solve these issues and achieve wider acceptance by the clinicians, granular ceramics have been associated with hydrogels (HGs) to produce injectable/moldable SBSs. Dextrin, a low-molecular-weight carbohydrate, was used to develop a fully resorbable and injectable HG. It was first oxidized with sodium periodate and then cross-linked with adipic acid dihydrazide. The in vivo biocompatibility and safety of the dextrin-based HG was assessed by subacute systemic toxicity and skin sensitization tests, using rodent models. The results showed that the HG did not induce any systemic toxic effect, skin reaction, or genotoxicity, neither impaired the bone repair/regeneration process. Then, the HG was successfully combined with granular bone substitute, registered as Bonelike (250-500 μm) to obtain a moldable/injectable SBS, which was implanted in tibial fractures in goats for 3 and 6 weeks. The obtained results showed that HG allowed the stabilization of the granules into the defect, ensuring effective handling, and molding properties of the formulation, as well as an efficient cohesion of the granules.