Browsing by Author "Antunes, A"
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- Differences in Nevirapine Biotransformation as a Factor for its Sex-Dependent Dimorphic Profile of Adverse Drug ReactionsPublication . Marinho, AT; Rodrigues, PM; Caixas, U; Antunes, A; Branco, T; Harjivan, S; Marques, MM; Monteiro, EC; Pereira, SAOBJECTIVES: Nevirapine is widely used for the treatment of HIV-1 infection; however, its chronic use has been associated with severe liver and skin toxicity. Women are at increased risk for these toxic events, but the reasons for the sex-related differences are unclear. Disparities in the biotransformation of nevirapine and the generation of toxic metabolites between men and women might be the underlying cause. The present work aimed to explore sex differences in nevirapine biotransformation as a potential factor in nevirapine-induced toxicity. METHODS: All included subjects were adults who had been receiving 400 mg of nevirapine once daily for at least 1 month. Blood samples were collected and the levels of nevirapine and its phase I metabolites were quantified by HPLC. Anthropometric and clinical data, and nevirapine metabolite profiles, were assessed for sex-related differences. RESULTS: A total of 52 patients were included (63% were men). Body weight was lower in women (P = 0.028) and female sex was associated with higher alkaline phosphatase (P = 0.036) and lactate dehydrogenase (P = 0.037) levels. The plasma concentrations of nevirapine (P = 0.030) and the metabolite 3-hydroxy-nevirapine (P = 0.035), as well as the proportions of the metabolites 12-hydroxy-nevirapine (P = 0.037) and 3-hydroxy-nevirapine (P = 0.001), were higher in women, when adjusted for body weight. CONCLUSIONS: There was a sex-dependent variation in nevirapine biotransformation, particularly in the generation of the 12-hydroxy-nevirapine and 3-hydroxy-nevirapine metabolites. These data are consistent with the sex-dependent formation of toxic reactive metabolites, which may contribute to the sex-dependent dimorphic profile of nevirapine toxicity.
- Do GnRH Agonists Really Increase Body Weight Gain? Evaluation of a Multicentric Portuguese Cohort of Patients With Central Precocious PubertyPublication . Leite, AL; Galo, E; Antunes, A; Robalo, B; Amaral, D; Espada, F; Castro, S; Simões Dias, S; Limbert, CIntroduction: There are several concerns associated with gonadotropin-releasing hormone agonist (GnRHa) treatment for central precocious puberty (CPP), such as obesity and changes in body mass index (BMI). We aimed to investigate whether any anthropometric differences exist and if they persist over time. Methods: We conducted an observational study of Portuguese children (both sexes) diagnosed with CPP between January 2000 and December 2017, using a digital platform, in order to analyze the influence of GnRHa treatment on BMI-SD score (BMI-SDS). Results: Of the 241 patients diagnosed with CPP, we assessed 92 patients (8% boys) in this study. At baseline, 39% of the patients were overweight. BMI-SDS increased with treatment for girls but then diminished 1 year after stopping GnRHa therapy (p = 0.018). BMI-SDS variation at the end of treatment was negatively correlated with BMI-SDS at baseline (p < 0.001). Boys grew taller and faster during treatment than did girls (p < 0.001), and therefore, their BMI-SDS trajectory might be different. Conclusions: This study showed an increase of body weight gain during GnRHa treatment only in girls, which reversed just 1 year after stopping treatment. The overall gain in BMI-SDS with treatment is associated with baseline BMI-SDS.
- Evidence for Nevirapine Bioactivation in Man: Searching for the First Step in the Mechanism of Nevirapine ToxicityPublication . Caixas, U; Antunes, A; Marinho, A; Godinho, A; Grilo, N; Marques, M; Oliveira, MC; Branco, T; Monteiro, E; Pereira, SDespite its efficacy, including in the prevention of vertical transmission, the antiretroviral nevirapine is associated with severe idiosyncratic hepatotoxicity and skin rash. The mechanisms underlying nevirapine toxicity are not fully understood, but drug bioactivation to reactive metabolites capable of forming stable protein adducts is thought to be involved. This hypothesis is based on the paradigm that drug reactive metabolites have the potential to bind to self-proteins, which results in drug-modified proteins being perceived as foreign by the immune system. The aim of the present work was to identify hemoglobin adducts in HIV patients as biomarkers of nevirapine haptenation upon bioactivation. The ultimate goal is to develop diagnostic methods for predicting the onset of nevirapine-induced toxic reactions. All included subjects were adults on nevirapine-containing antiretroviral therapy for at least 1month. The protocol received prior approval from the Hospital Ethics Committees and patients gave their written informed consent. Nevirapine-derived adducts with the N-terminal valine of hemoglobin were analyzed by an established liquid chromatography-electrospray ionization-tandem mass spectrometry method and characterized on the basis of retention time and mass spectrometric fragmentation pattern by comparison with adduct standards prepared synthetically. The nevirapine adducts were detected in 12/13 patient samples, and quantified in 11/12 samples (2.58±0.8 fmol/g of hemoglobin). This work represents the first evidence of nevirapine-protein adduct formation in man and confirms the ability of nevirapine to modify self-proteins, thus providing clues to the molecular mechanisms underlying nevirapine toxicity. Moreover, the possibility of assessing nevirapine-protein adduct levels has the potential to become useful for predicting the onset of nevirapine-induced adverse reactions.
- Height Benefit of GnRH Agonists After Age 8 in a Portuguese Cohort of Central Precocious PubertyPublication . Castro, C; Espada, F; Leite, AL; Antunes, A; Robalo, B; Amaral, D; Galo, E; Castro, S; Ferreira, S; Limbert, CObjective: Idiopathic central precocious puberty (iCPP) is common in paediatric endocrinology. Gonadotropin-releasing hormone agonists (GnRHa) are safe, but the effect on final height and the ideal timing for treatment remains controversial. This study aims to assess the effectiveness of GnRHa on growth outcomes in girls with iCPP treated before and after the age of 8 years old. Design and patients: This retrospective longitudinal study evaluated data from Portuguese girls with iCPP who completed treatment between 2010 and 2021. Measurements: Auxological and clinical characteristics were compared according to age at treatment onset. Results: A cohort of 134 girls with iCPP, was divided into early treatment (ET) (<8 years, n = 48) and later treatment (LT) groups (≥8 years, n = 86). In both groups, most children presented with Tanner II and III. Tanner IV was more frequent in LT group (p = .003). At the end of treatment, predicted adult height increased in both groups (ET p = .032; LT p = .04) and bone age significantly slowed down in all participants (p = .008, p = .034). The height gain was greater in the ET group, but without significant differences (p = .065). Conclusions: Treatment with GnRHa improved final height in all girls with iCPP, even when initiated after 8 years. To achieve better outcomes, treatment should be provided promptly after diagnosis
- Monitoring Abacavir Bioactivation in Humans: Screening for an Aldehyde MetabolitePublication . Grilo, N; Antunes, A; Caixas, U; Marinho, A; Charneira, C; Oliveira, MC; Monteiro, E; Marques, MM; Pereira, SThe anti-HIV drug abacavir is associated with idiosyncratic hypersensitivity reactions and cardiotoxicity. Although the mechanism underlying abacavir-toxicity is not fully understood, drug bioactivation to reactive metabolites may be involved. This work was aimed at identifying abacavir-protein adducts in the hemoglobin of HIV patients as biomarkers of abacavir bioactivation and protein modification. The protocol received prior approval from the Hospital Ethics Committee, patients gave their written informed consent and adherence was controlled through a questionnaire. Abacavir-derived Edman adducts with the N-terminal valine of hemoglobin were analyzed by an established liquid chromatography-electrospray ionization-tandem mass spectrometry method. Abacavir-valine adducts were detected in three out of ten patients. This work represents the first evidence of abacavir-protein adduct formation in humans. The data confirm the ability of abacavir to modify self-proteins and suggest that the molecular mechanism(s) of some abacavir-induced adverse reactions may require bioactivation.
- The Impact of COVID-19 on Rare and Complex Connective Tissue Diseases: the Experience of ERN ReCONNETPublication . Talarico, R; Aguilera, S; Alexander, T; Amoura, Z; Antunes, A; Arnaud, L; Avcin, T; Beretta, L; Bombardieri, S; Burmester, G; Cannizzo, S; Cavagna, L; Chaigne, B; Cornet, A; Costedoat-Chalumeau, N; Doria, A; Ferraris, A; Fischer-Betz, R; Fonseca, J; Frank, C; Gaglioti, A; Galetti, I; Grunert, J; Guimarães, V; Hachulla, E; Houssiau, F; Iaccarino, L; Krieg, T; Limper, M; Malfait, F; Mariette, X; Marinello, D; Martin, T; Matthews, L; Matucci-Cerinic, M; Meyer, A; Montecucco, C; Mouthon, L; Müller-Ladner, U; Rednic, S; Romão, V; Schneider, M; Smith, V; Sulli, A; Tamirou, F; Taruscio, D; Taulaigo, A; Terol, E; Tincani, A; Ticciati, S; Turchetti, G; van Hagen, P; van Laar, J; Vieira, A; de Vries-Bouwstra, J; Cutolo, M; Mosca, MDuring the COVID-19 pandemic, the need to provide high-level care for a large number of patients with COVID-19 has affected resourcing for, and limited the routine care of, all other conditions. The impact of this health emergency is particularly relevant in the rare connective tissue diseases (rCTDs) communities, as discussed in this Perspective article by the multi-stakeholder European Reference Network on Rare and Complex Connective Tissue and Musculoskeletal Diseases (ERN ReCONNET). The clinical, organizational and health economic challenges faced by health-care providers, institutions, patients and their families during the SARS-CoV-2 outbreak have demonstrated the importance of ensuring continuity of care in the management of rCTDs, including adequate diagnostics and monitoring protocols, and highlighted the need for a structured emergency strategy. The vulnerability of patients with rCTDs needs to be taken into account when planning future health policies, in preparation for not only the post-COVID era, but also any possible new health emergencies.