Thyroxine does not improve skeletal muscle regeneration after injury in aged mice Thamires Siqueira Oliveira, Alexander Pereira-Rosa, Matheus da Silva Ferreira, Victoria Regina Siqueira Monteiro, Juliana de Brito, et al. Journal of Endocrinology, 2025 Graphical Abstract Abstract Thyroid hormone levels decrease with aging, and low thyroxine levels are correlated with sarcopenia development. While thyroid hormone stimulates myogenesis in young subjects, its effect on aged muscle regeneration is unclear. We aimed to investigate the impact of a low dose of thyroxine (T4) replacement therapy (7.5 ng/g body weight) on tibial anterior regeneration 7 days after injury by 1.2% BaCl 2 injection in 24–27-month-old male mice. Our primary data suggest that regenerating aged skeletal muscle exhibits local resistance to thyroid hormone action without altering myogenic regulatory factors expression. However, T4 treatment decreases the number of central nuclei, indicative of newly formed fibers. In addition, we observed a decrease in cross-sectional area and an increase in myonuclei domain, cell death, and laminin expression in T4-treatment injured muscles. Rather than improving regeneration, T4 replacement therapy appears to induce atrophy and tissue remodeling. Our data highlight the need to understand aging physiology since thyroid hormones are crucial for muscle regeneration in young animals, although T4 replacement therapy does not improve muscle regeneration post-injury in elderly mice. This research may support clinical recommendations against treating sarcopenic patients with subclinical hypothyroidism, especially following fall-related injuries.
Prenatal Exposure to Herbicide 2,4-Dichlorophenoxyacetic Acid (2,4D) Exacerbates Zika Virus Neurotoxicity In Vitro and In Vivo Raissa Rilo Christoff, Débora Santos da Silva, Rafael Ferreira Lima, Ana Luiza Meneguci Moreira Franco, Luiza Mendonça Higa, et al. Environmental Toxicology, 2025 Zika virus (ZIKV) infection during pregnancy can lead to a set of congenital malformations known as Congenital ZIKV syndrome (CZS), whose main feature is microcephaly. The geographic distribution of CZS in Brazil during the 2015–2017 outbreak was asymmetrical, with a higher prevalence in the Northeast and Central‐West regions of the country, despite the ubiquitous distribution of the vector Aedes aegypti, indicating that environmental factors could influence ZIKV vertical transmission and/or severity. Here we investigate the involvement of the most used agrochemicals in Brazil with CZS. First, we exposed human neuroblastoma SK‐N‐AS cells to the 15 frequently used agrochemical molecules or derivative metabolites able to cross the blood–brain barrier. We found that a derived metabolite from a widely used herbicide in the Central‐West region, 2,4‐dichlorophenoxyacetic acid (2,4D), exacerbates ZIKV neurotoxic effects in vitro. We validate this observation by demonstrating vertical transmission leading to microcephaly in the offspring of immunocompetent C57BL/6J mice exposed to water contaminated with 0.025 mg/L of 2,4D. Newborn mice whose dams were exposed to 2,4D and infected with ZIKV presented a smaller brain area and cortical plate size compared to the control. Also, embryos from animals facing the co‐insult of ZIKV and 2,4D exposition presented higher Caspase 3 positive cells in the cortex, fewer CTIP2+ neurons and proliferative cells at the ventricular zone, and a higher viral load. This phenotype is followed by placental alterations, such as vessel congestion, and apoptosis in the labyrinth and decidua. We also observed a mild spatial correlation between CZS prevalence and 2,4D use in Brazil's North and Central‐West regions, with R2 = 0.4 and 0.46, respectively. Our results suggest that 2,4D exposition facilitates maternal vertical transmission of ZIKV, exacerbating CZS, possibly contributing to the high prevalence of this syndrome in Brazil's Central‐West region compared to other regions.
Sex-specific effect of antenatal Zika virus infection on murine fetal growth, placental nutrient transporters, and nutrient sensor signaling pathways Daniela Pereira‐Carvalho, Alessandra Cristina Chagas Valim, Cherley Borba Vieira Andrade, Enrrico Bloise, Ariane Fontes Dias, et al. FASEB Journal, 2024 Maternal Zika virus (ZIKV) infection during pregnancy has been associated with severe intrauterine growth restriction (IUGR), placental damage, metabolism disturbances, and newborn neurological abnormalities. Here, we investigated the impact of maternal ZIKV infection on placental nutrient transporters and nutrient‐sensitive pathways. Immunocompetent (C57BL/6) mice were injected with Low (103 PFU‐ZIKVPE243) or High (5 × 107 PFU‐ZIKVPE243) ZIKV titers at gestational day (GD) 12.5, and tissue was collected at GD18.5 (term). Fetal–placental growth was impaired in male fetuses, which exhibited higher placental expression of the ZIKV infective marker, eukaryotic translation initiation factor 2 (eIF2α), but lower levels of phospho‐eIF2α. There were no differences in fetal–placental growth in female fetuses, which exhibited no significant alterations in placental ZIKV infective markers. Furthermore, ZIKV promoted increased expression of glucose transporter type 1 (Slc2a1/Glut1) and decreased levels of glucose‐6‐phosphate in female placentae, with no differences in amino acid transport potential. In contrast, ZIKV did not impact glucose transporters in male placentae but downregulated sodium‐coupled neutral amino acid 2 (Snat2) transporter expression. We also observed sex‐dependent differences in the hexosamine biosynthesis pathway (HBP) and O‐GlcNAcylation in ZIKV‐infected pregnancies, showing that ZIKV can disturb placental nutrient sensing. Our findings highlight molecular alterations in the placenta caused by maternal ZIKV infection, shedding light on nutrient transport, sensing, and availability. Our results also suggest that female and male placentae employ distinct coping mechanisms in response to ZIKV‐induced metabolic changes, providing insights into therapeutic approaches for congenital Zika syndrome.
Vitamin D and follicular recruitment in the in vitro fertilization cycle Roberto A Antunes, Brenda M. L de Melo, Maria do Carmo Borges de Souza, Marcelo Marinho de Souza, Gabriela Palhano Sifuentes Melo, et al. Jornal Brasileiro De Reproducao Assistida, 2024 OBJECTIVE Vitamin D (VD) is a fat-soluble steroid hormone, synthesized by the skin, most known for its role in bone mineral balance. Vitamin D receptors (VDR) are also found in the female reproductive system, but their role remains unclear. The objective of this study was to analyze the relationship between serum vitamin D levels and the number of oocytes retrieved after ovarian stimulation. METHODS This is a retrospective study involving 267 patients undergoing in vitro fertilization (IVF) carried out in the Fertipraxis clinic, a private practice facility. The patients were initially divided into two groups according to their VD levels. Group 1 included 152 patients with VD levels < 30 ng/mL and group 2 had 115 patients with VD levels > 30 ng/mL. They were further analyzed and separated considering their age, anthropometric data, ovarian reserve, amount of gonadotropin used, and follicles obtained until trigger day. RESULTS In our analysis, there were no difference in the number of follicles and oocytes retrieved, nor in the number of mature oocytes obtained from patients with both vitamin D deficiency and sufficiency. CONCLUSIONS The results of our study show no difference among number of follicles, oocytes retrieved and mature oocytes obtained after ovarian stimulation according to their vitamin D serum levels. Further higher-quality studies are needed to evaluate the possible roles of serum vitamin D levels in other stages of human fertilization process.
Metabolomic analysis of follicular fluid from women with Hashimoto thyroiditis Diana Caroline da Silva Bastos, Maria Izabel Chiamolera, Renata Elen Silva, Maria Do Carmo Borges de Souza, Roberto Azevedo Antunes, et al. Scientific Reports, 2023 Hashimoto thyroiditis is an autoimmune disease characterized by hypothyroidism and a high level of anti-thyroid autoantibodies. It has shown to negatively impact female fertility; however, the mechanisms are unclear. Ovarian follicular fluid appears to be the key to understanding how Hashimoto thyroiditis affecst fertility. Thus, we aimed to evaluated the metabolic profile of follicular fluid and antithyroid autoantibody levels in the context of Hashimoto thyroiditis. We collected follicular fluid from 61 patients, namely 38 women with thyroid autoantibody positivity and 23 women as negative controls, undergoing in vitro fertilization treatment. Follicular fluid samples were analyzed using metabolomics, and thyroid autoantibodies were measured. Fifteen metabolites with higher concentrations in the follicular fluid samples from Hashimoto thyroiditis were identified, comprising five possible affected pathways: the glycerophospholipid, arachidonic acid, linoleic acid, alpha-linolenic acid, and sphingolipid metabolism pathways. These pathways are known to regulate ovarian functions. In addition, antithyroglobulin antibody concentrations in both serum and follicular fluid were more than tenfold higher in women with Hashimoto thyroiditis than in controls. Our data showed that the metabolic profile of follicular fluid is altered in women with Hashimoto thyroiditis, suggesting a potential mechanistic explanation for the association of this disease with female infertility.
Immunostaining of βA-Activin and Follistatin Is Decreased in HPV(+) Cervical Pre-Neoplastic and Neoplastic Lesions Victor Jesus Huaringa Payano, Lara Verônica de Araújo Lopes, Larissa Rodrigues Peixoto, Keila Alves da Silva, Tania Maria Ortiga-Carvalho, et al. Viruses, 2023 The activin–follistatin system regulates several cellular processes, including differentiation and tumorigenesis. We hypothesized that the immunostaining of βA-activin and follistatin varies in neoplastic cervical lesions. Cervical paraffin-embedded tissues from 162 patients sorted in control (n = 15), cervical intraepithelial neoplasia (CIN) grade 1 (n = 38), CIN2 (n = 37), CIN3 (n = 39), and squamous cell carcinoma (SCC; n = 33) groups were examined for βA-activin and follistatin immunostaining. Human papillomavirus (HPV) detection and genotyping were performed by PCR and immunohistochemistry. Sixteen samples were inconclusive for HPV detection. In total, 93% of the specimens exhibited HPV positivity, which increased with patient age. The most detected high-risk (HR)-HPV type was HPV16 (41.2%) followed by HPV18 (16%). The immunostaining of cytoplasmatic βA-activin and follistatin was higher than nuclear immunostaining in all cervical epithelium layers of the CIN1, CIN2, CIN3, and SCC groups. A significant decrease (p < 0.05) in the cytoplasmic and nuclear immunostaining of βA-activin was detected in all cervical epithelial layers from the control to the CIN1, CIN2, CIN3, and SCC groups. Only nuclear follistatin immunostaining exhibited a significant reduction (p < 0.05) in specific epithelial layers of cervical tissues from CIN1, CIN2, CIN3, and SCC compared to the control. Decreased immunostaining of cervical βA-activin and follistatin at specific stages of CIN progression suggests that the activin–follistatin system participates in the loss of the differentiation control of pre-neoplastic and neoplastic cervical specimens predominantly positive for HPV.
