Centre for Toxicogenomics and Human Health

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Analysis of the Characteristics and Cytotoxicity of Titanium Dioxide Nanomaterials Following Simulated In Vitro Digestion

Publication . Bettencourt, Ana; Gonçalves, Lídia; Gramacho, Ana C.; Vieira, Adriana; Rolo, Dora; Martins, Carla; Assunção, Ricardo; Alvito, Paula; Silva, Maria João; Louro, Henriqueta

Several metallic nanomaterials (NMs), such as titanium dioxide nanomaterials (TiO2), present beneficial properties with a broad range of innovative applications. The human population is exposed to TiO2, particularly by ingestion, due to its increasing use as a food additive and inclusion in dietary supplements and food packaging materials. Whether this oral exposure may lead to adverse local or systemic outcomes has been the subject of research, but studies have generated contradictory results, reflecting differences in the physicochemical properties of the TiO2 studied, effects of the surrounding matrix, and modifications during digestion. This work aimed to investigate the toxic effects of three different TiO2 NMs (NM-103, NM-103 and NM-105) on the gastrointestinal tract cells, Caco-2 and HT29-MTX-E12, after the use of the standardized static INFOGEST 2.0 in vitro digestion method to mimic human digestion of TiO2, contributing to hazard assessment. The results show that, for one of the digested TiO2 NMs studied (NM-105), a more pronounced toxicity occurs after exposure of HT29-MTX-E12 intestinal cells, as compared to undigested NM, concomitantly with subtle changes in characteristics of the NM. Thus, the inclusion of the digestion simulation in the safety evaluation of ingested NMs through in vitro bioassays can better integrate the modifications that NMs suffer in the organism. It is expected that such an approach will reduce uncertainties in the hazard assessment of ingested NMs for human health.

2020-08-02Artigo científico

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Common genetic variation in KATNAL1 non‐coding regions is involved in the susceptibility to severe phenotypes of male infertility

Publication . Cerván‐Martín, Miriam; Bossini‐Castillo, Lara; Guzmán‐Jiménez, Andrea; Rivera‐Egea, Rocío; Garrido, Nicolás; Lujan, Saturnino; Romeu, Gema; Santos-Ribeiro, Samuel; Castilla, José Antonio; Gonzalvo, María del Carmen; Clavero, Ana; Maldonado, Vicente; Vicente, Francisco Javier; Burgos, Miguel; Jiménez, Rafael; González‐Muñoz, Sara; 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 Manuel; Palomino‐Morales, Rogelio Jesús; Carmona, Francisco David

Background: Previous studies in animal models evidenced that genetic mutations of KATNAL1, resulting in dysfunction of its encoded protein, lead to male infertility through disruption of microtubule remodelling and premature germ cell exfoliation. Subsequent studies in humans also suggested a possible role of KATNAL1 single-nucleotide polymorphisms in the development of male infertility as a consequence of severe spermatogenic failure. Objectives: The main objective of the present study is to evaluate the effect of the common genetic variation of KATNAL1 in a large and phenotypically well-characterised cohort of infertile men because of severe spermatogenic failure. Materials and methods: A total of 715 infertile men because of severe spermatogenic failure, including 210 severe oligospermia and 505 non-obstructive azoospermia patients, as well as 1058 unaffected controls were genotyped for three KATNAL1 single-nucleotide polymorphism taggers (rs2077011, rs7338931 and rs2149971). Case-control association analyses by logistic regression assuming different models and in silico functional characterisation of risk variants were conducted. Results: Genetic associations were observed between the three analysed taggers and different severe spermatogenic failure groups. However, in all cases, the haplotype model (rs2077011*C | rs7338931*T | rs2149971*A) better explained the observed associations than the three risk alleles independently. This haplotype was associated with non-obstructive azoospermia (adjusted p = 4.96E-02, odds ratio = 2.97), Sertoli-cell only syndrome (adjusted p = 2.83E-02, odds ratio = 5.16) and testicular sperm extraction unsuccessful outcomes (adjusted p = 8.99E-04, odds ratio = 6.13). The in silico analyses indicated that the effect on severe spermatogenic failure predisposition could be because of an alteration of the KATNAL1 splicing pattern. Conclusions: Specific allelic combinations of KATNAL1 genetic polymorphisms may confer a risk of developing severe male infertility phenotypes by favouring the overrepresentation of a short non-functional transcript isoform in the testis.

2022Artigo científico

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Entidade financiadora

Fundação para a Ciência e a Tecnologia

Programa de financiamento

6817 - DCRRNI ID

Número da atribuição

UIDB/00009/2020