Phosphorylation of eIF2α mitigates endoplasmic reticulum stress and hepatocyte necroptosis in acute liver injury.

INTRODUCTION AND OBJECTIVES: Necroptosis and endoplasmic reticulum (ER) stress has been implicated in acute and chronic liver injury. Activated eukaryotic initiation factor 2 alpha (eIF2α) attenuates protein synthesis and relieves the load of protein folding in the ER. In this study, we aimed to analyze the impact of eIF2α phosphorylation on hepatocyte necroptosis in acute liver injury. MATERIALS AND METHODS: Male BALB/c mice were injected with tunicamycin or d-galactosamine, and LO2 cells were incubated with tunicamycin to induce acute liver injury. 4-Phenylbutyric acid (PBA) and salubrinal were used to inhibit ER stress and eIF2α dephosphorylation, respectively. We analyzed the eIF2α phosphorylation, ER stress, and hepatocyte necroptosis in mice and cells model. RESULTS: Tunicamycin or d-galactosamine significantly induced ER stress and necroptosis, as well as eIF2α phosphorylation, in mice and LO2 cells (p<0.05). ER stress aggravated tunicamycin-induced hepatocyte necroptosis in mice and LO2 cells (p<0.05). Elevated eIF2α phosphorylation significantly mitigated hepatocyte ER stress (p<0.05) and hepatocyte necroptosis in mice (34.37±3.39% vs 22.53±2.18%; p<0.05) and LO2 cells (1±0.11 vs 0.33±0.05; p<0.05). Interestingly, tumor necrosis factor receptor (TNFR) 1 protein levels were not completely synchronized with necroptosis. TNFR1 expression was reduced in d-galactosamine-treated mice (p<0.05) and cells incubated with tunicamycin for 12 and 24h (p<0.05). ER stress partially restored TNFR1 expression and increased necroptosis in tunicamycin-incubated cells (p<0.05). CONCLUSIONS: These results imply that ER stress can mediate hepatocyte necroptosis independent of TNFR1 signaling and elevated eIF2α phosphorylation can mitigate ER stress during acute liver injury.

Advanced bone age as an indicator facilitates the diagnosis of precocious puberty / Idade óssea avançada como um indicador de facilitação do diagnóstico de puberdade precoce

Abstract Objective: Diagnosis of central precocious puberty has always been challenging in clinical practice. As an important method in the diagnosis of central precocious puberty, luteinizing hormone-releasing hormone stimulation test is complex and time-consuming. In many cases, clinical traits are inconsistent with luteinizing hormone-releasing hormone stimulation test results, therefore not reliable for diagnosis. In this study, the authors intended to find an indicator that predicts the results of the luteinizing hormone-releasing hormone stimulation test among subjects with early pubertal signs. Methods: Cases of 382 girls with early breast development before 8 years old and luteinizing hormone-releasing hormone stimulation test before 9 years old were included and underwent follow-up tests. Patients with peak luteinizing hormone level ≥5 IU/L were considered positive in the luteinizing hormone-releasing hormone stimulation test. Anthropometric data, body mass index, bone age evaluation, blood hormones levels of luteinizing hormone, estradiol, follicle-stimulating hormone, and uterine and ovarian volumes were analyzed. Results: Subjects with positive results in the initial test demonstrated early bone maturation, accelerated growth, and elevated basal blood luteinizing hormone, estradiol, and follicle-stimulating hormone levels, when compared with subjects with negative results in the initial test. Subjects with positive results in the follow-up test presented a more advanced bone age and more accelerated linear growth, when compared with subjects with negative results in the follow-up test. Conclusions: According to the statistical analysis, advanced bone age is the most effective predictor of the result of luteinizing hormone-releasing hormone stimulation test.

Resumo Objetivo: O diagnóstico da puberdade precoce central sempre foi complicado na prática clínica. Como um importante método no diagnóstico de puberdade precoce central, o teste de estimulação do hormônio liberador do hormônio luteinizante é complexo e demorado. Em muitos casos, as características clínicas são incompatíveis com os resultados do teste de estimulação do hormônio liberador do hormônio luteinizante e, assim, não são confiáveis para o diagnóstico. Neste estudo, visamos constatar um indicador que previsse os resultados do teste de estimulação do hormônio liberador do hormônio luteinizante entre indivíduos com sinais puberais precoces. Métodos: Foram incluídos casos de 382 meninas com desenvolvimento precoce das mamas antes dos 8 anos de idade e teste de estimulação do hormônio liberador do hormônio luteinizanteantes dos 9 anos e elas foram submetidas a testes de acompanhamento. Os resultados das pacientes com nível máximo de hormônio luteinizante ≥ 5 IU/L foram consideradas positivos no teste de estimulação do hormônio liberador do hormônio luteinizante. Foi feita uma análise dos dados antropométricos, do índice de massa corporal, da avaliação da idade óssea, dos níveis sanguíneos de hormônio luteinizante, volumes uterinos e ovarianos de estradiol (E2) e do hormônio folículo-estimulante. Resultados: Os indivíduos com resultado positive no teste inicial demonstraram maturação precoce do osso, crescimento acelerado e níveis sanguíneos elevados de hormônio luteinizante, estradiol e hormônio folículo-estimulante, em comparação aos indivíduos com resultados negativos no teste inicial. Os indivíduos com resultados positivos no teste de acompanhamento apresentaram um maior avanço na idade óssea e crescimento linear mais acelerado, em comparação aos indivíduos com resultados negativos no teste de acompanhamento. Conclusões: De acordo com a análise estatística, a idade óssea avançada é o indicador mais efetivo do resultado do teste de estimulação do hormônio liberador do hormônio luteinizante.

Advanced bone age as an indicator facilitates the diagnosis of precocious puberty.

OBJECTIVE: Diagnosis of central precocious puberty has always been challenging in clinical practice. As an important method in the diagnosis of central precocious puberty, luteinizing hormone-releasing hormone stimulation test is complex and time-consuming. In many cases, clinical traits are inconsistent with luteinizing hormone-releasing hormone stimulation test results, therefore not reliable for diagnosis. In this study, the authors intended to find an indicator that predicts the results of the luteinizing hormone-releasing hormone stimulation test among subjects with early pubertal signs. METHODS: Cases of 382 girls with early breast development before 8 years old and luteinizing hormone-releasing hormone stimulation test before 9 years old were included and underwent follow-up tests. Patients with peak luteinizing hormone level ≥5IU/L were considered positive in the luteinizing hormone-releasing hormone stimulation test. Anthropometric data, body mass index, bone age evaluation, blood hormones levels of luteinizing hormone, estradiol, follicle-stimulating hormone, and uterine and ovarian volumes were analyzed. RESULTS: Subjects with positive results in the initial test demonstrated early bone maturation, accelerated growth, and elevated basal blood luteinizing hormone, estradiol, and follicle-stimulating hormone levels, when compared with subjects with negative results in the initial test. Subjects with positive results in the follow-up test presented a more advanced bone age and more accelerated linear growth, when compared with subjects with negative results in the follow-up test. CONCLUSIONS: According to the statistical analysis, advanced bone age is the most effective predictor of the result of luteinizing hormone-releasing hormone stimulation test.