Recovery of insulin sensitivity and Slc2a4 mRNA expression depend on T3 hormone during refeeding

Objective

GLUT4 protein, encoded by the Slc2a4 gene, plays a key role in muscle glucose uptake, and its expression decreases in muscles under insulin resistance. Slc2a4/GLUT4 decreases with fasting and rapidly increases with refeeding and the same occurs to plasma glucose, amino acids, insulin and T3. Thus, they might be potential regulators of the Slc2a4 gene, which makes them promising targets for strategies to improve GLUT4 expression. Herein, we investigate the role of metabolic–hormonal parameters triggered by refeeding upon the Slc2a4 expression.

Materials/Methods

Plasma glucose/insulin/T3, and gastrocnemius Slc2a4 mRNA contents were measured in rats studied at the end of 48-h fasting, and subsequently at: i) 2–4 h after spontaneous refeeding; ii) 2–4 h after T3 injection, without refeeding; and iii) 0.5–2 h after intravenous infusion of insulin, insulin + glucose and insulin + amino acids, without refeeding.

Results

Refeeding increased plasma glucose/insulin/T3 and muscle Slc2a4 mRNA, reverting insulin resistance. Post-fasting infusions surprisingly induced a further Slc2a4 mRNA decrease (~ 20%, P < 0.05 vs. fasting), but T3 injection induced a ~ 2-fold increase in Slc2a4 mRNA, 2–4 h later (P < 0.001). Moreover, T3 increased glycemia and insulinemia to the 2 h-refed rats levels, suggesting that T3 elevation is a key factor to the mechanisms of metabolic balance during refeeding.

Conclusions

Refeeding induces a rapid increase in muscle Slc2a4 expression, not associated with increased plasma glucose, insulin or amino acids, but highly correlated to increased plasma T3 concentration. This result points out T3 hormone as a powerful Slc2a4 enhancer, an effect that may be acutely explored in situations of insulin resistance.     

Differential processing of Arabidopsis ubiquitin-like Atg8 autophagy proteins by Atg4 cysteine proteases

Autophagy is a highly conserved biological process during which double membrane bound autophagosomes carry intracellular cargo material to the vacuole or lysosome for degradation and/or recycling. Autophagosome biogenesis requires Autophagy 4 (Atg4) cysteine protease-mediated processing of ubiquitin-like Atg8 proteins. Unlike single Atg4 and Atg8 genes in yeast, the Arabidopsis genome contains two Atg4 (AtAtg4a and AtAtg4b) and nine Atg8 (AtAtg8a–AtAtg8i) genes. However, we know very little about specificity of different AtAtg4s for processing of different AtAtg8s. Here, we describe a unique bioluminescence resonance energy transfer-based AtAtg8 synthetic substrate to assess AtAtg4 activity in vitro and in vivo. In addition, we developed a unique native gel assay of superhRLUC catalytic activity assay to monitor cleavage of AtAtg8s in vitro. Our results indicate that AtAtg4a is the predominant protease and that it processes AtAtg8a, AtAtg8c, AtAtg8d, and AtAtg8i better than AtAtg4b in vitro. In addition, kinetic analyses indicate that although both AtAtg4s have similar substrate affinity, AtAtg4a is more active than AtAtg4b in vitro. Activity of AtAtg4s is reversibly inhibited in vitro by reactive oxygen species such as H₂O₂. Our in vivo bioluminescence resonance energy transfer analyses in Arabidopsis transgenic plants indicate that the AtAtg8 synthetic substrate is efficiently processed and this is AtAtg4 dependent. These results indicate that the synthetic AtAtg8 substrate is used efficiently in the biogenesis of autophagosomes in vivo. Transgenic Arabidopsis plants expressing the AtAtg8 synthetic substrate will be a valuable tool to dissect autophagy processes and the role of autophagy during different biological processes in plants.Macroautophagy, hereafter referred to as autophagy, is an evolutionarily conserved biological process from yeast to higher eukaryotes including plants (1–4). During autophagy, intracellular components are enclosed in double membrane vesicles called autophagosomes. Cargoes in autophagosomes are then delivered to the vacuole or the lysosome for degradation or recycling. Biogenesis of autophagosomes requires conjugation of phosphatidylethanolamine (PE) to ubiquitin-like Atg8 proteins (1, 5). Before PE conjugation, the Atg8 protein is posttranslationally processed by Atg4 cysteine protease at the conserved C-terminal glycine (Gly) residue (6). The exposed Gly residue is then implicated in adduct with PE. Atg4 is also required for a deconjugation step in which Atg8-PE is removed from the outer membrane of autophagosome for Atg8 recycling and autophagosome completion (7, 8).Compared with single Atg4 and Atg8 genes in yeast, the Arabidopsis genome contains two AtAtg4 (AtAtg4a and AtAtg4b) and nine AtAtg8 (AtAtg8a–AtAtg8i) genes (9, 10). However, we know very little about specificity of different AtAtg4s for processing of different AtAtg8 isoforms. Because AtAtg4 and AtAtg8 genes are differentially regulated under different environmental conditions, we and others have proposed that the expansion of AtAtg4 and AtAtg8 members may provide specificity for activating autophagy during different biological processes (11–13).To test differential activity of AtAtg4s, we have systematically investigated the specificity of AtAtg4a and AtAtg4b cysteine proteases for processing of different AtAtg8s. For this, we designed unique AtAtg8 synthetic substrates and developed a sensitive method to follow the processing of AtAtg8s. Our results indicate that AtAtg4a is a predominant protease and it processes AtAtg8a, AtAtg8c, AtAtg8d, and AtAtg8i better than AtAtg4b in vitro. In addition, kinetic analyses indicate that although both AtAtg4s have similar substrate affinity, AtAtg4a is more active than AtAtg4b in vitro. The AtAtg8 synthetic substrate is also efficiently processed in vivo in Arabidopsis transgenic plants and this processing requires endogenous AtAtg4 proteases. Transgenic Arabidopsis plants expressing the AtAtg8a synthetic substrate described here will be a valuable tool to dissect the autophagy process and its role in different biological processes.     

Relevance of Pulmonary Alveolar Echinococcosis

BackgroundPulmonary alveolar echinococcosis (PAE) is a chronic disease caused by Echinococcus multilocularis with very low incidence in developed countries.MethodsThis single-center, retrospective study included 34 patients who were diagnosed with PAE between January 2001 and February 2019 (15 males, 19 females, mean age: 52.4 ± 15.8 years, age range: 28–78 years) in Ataturk University Medical School, Erzurum, Turkey.ResultsThe liver was the primary involved organ in all cases. Pulmonary involvement was detected in 13.0% (34/261) of all cases with hepatic alveolar echinococcosis (AE), and three patients (8.8%) had both pulmonary metastasis and brain metastasis. The route of spread to the lungs based on radiological data was hematogeneous in 25 patients (73.5%), transdiaphragmatic in three patients (8.8%) and both hematogeneous and transdiaphragmatic in six patients (17.7%). AE showed bilateral involvement in 19 patients (55.9%), whereas only the right lung was involved in 12 patients (35.3%) and the left lung in three patients (8.8%). Of the patients, five underwent surgery due to PAE and 29 patients received medical therapy with albendazole. A total of three patients died during the follow-up period (2, 5 and 10 years after the diagnosis of PAE), while 31 patients continued with follow-up and treatment for a mean duration of 5.4 ± 3.8 years (1–14 years).ConclusionsPatients with hepatic AE must, as a matter of course, be screened for possible lung involvement. Albendazole therapy may slow down disease progression in patients with widespread pulmonary involvement who are not eligible for surgery.     

纳入血浆脂蛋白(a)的家族性高胆固醇血症改良诊断模型的探索性研究

目的:本研究旨在建立纳入血浆脂蛋白(a)[Lp(a)]的家族性高胆固醇血症(FH)的改良诊断模型,并将其诊断性能与荷兰脂质诊所网络(DLCN)标准、中国人群FH简化诊断标准(CSCFH)进行比较。方法:选取2011年5月至2018年1月期间接受冠状动脉造影的受试者10320例用于FH改良诊断模型的建立(7740例为建模人群,2580例为外部验证人群),在DLCN标准的基础上得到改良诊断模型。结果:FH改良诊断模型的诊断项目包括未经治疗的低密度脂蛋白胆固醇(LDL-C)水平、Lp(a)、早发冠心病、肌腱黄色瘤和早发冠心病家族史或高胆固醇血症家族史,并给以上指标确定分值,将总分≥6分时可诊断为临床FH。改良诊断模型与DLCN标准一致性良好,在建模人群中κ=0.766,在外部验证人群中κ=0.721(P均<0.001),与CSCFH的一致性一般(κ=0.495)。结论:纳入Lp(a)的新型改良诊断模型具有较好的诊断效能,可以为中国人群的FH诊断提供新的见解。     

血浆脂蛋白(a)浓度与青年人群冠心病关系的横断面研究

目的:探讨血浆脂蛋白(a)[Lp(a)]浓度与青年人群冠心病的相关性。方法:选取2018年3月至2019年2月期间在中国医学科学院阜外医院行冠状动脉造影术的1 093例青年患者作为研究对象(<45岁),按照冠状动脉造影结果分为冠心病组(n=906)和非冠心病组(n=187)。采用Gensini评分法评估冠心病组患者的冠状动脉病变严重程度,并将其分为三个亚组:高Gensini评分亚组(n=302)、中Gensini评分亚组(n=302)、低Gensini评分亚组(n=302)。收集所有研究对象的病史及相关临床与实验室检测指标,血浆Lp(a)检测采用免疫比浊法;分析基线血浆Lp(a)浓度与冠心病诊断及严重程度之间的关系。结果:冠心病组患者血浆Lp(a)浓度显著高于非冠心病组[13.46(6.58~28.91)mg/dl vs 8.39(5.06~19.31)mg/dl,P<0.001]。进一步分析显示,冠心病组男性、女性、高血压、无高血压、无糖尿病患者的血浆Lp(a)浓度均显著高于非冠心病组(P均<0.05)。多因素Logistic回归分析表明,logLp(a)水平升高为青年冠心病的独立危险因素(OR=2.898,95%CI:1.949~4.311,P<0.001)。在冠心病组患者中,高Gensini评分亚组的Lp(a)浓度明显高于中Gensini评分亚组及低Gensini评分亚组[18.07(9.22~40.29)mg/dl vs13.89(6.57~32.77)mg/dl、9.63(4.83~18.96)mg/dl,P均<0.001]。多元线性回归分析表明,较高logLp(a)水平与高Gensini评分显著相关(B=0.353,P<0.001)。结论:横断面观察提示,血浆Lp(a)浓度与青年人群冠心病的发生及病变严重程度相关,其结果有待更大样本前瞻性研究证实。     

Uso equitativo de tests en ciencias de la salud

Standardized measurement instruments (tests) have become an essential tool in health sciences. The concept of equity in the development, adaptation and administration of psychometric tests was first introduced in «Standards for Educational and Psychological Testing» published in 1999 by the American Educational Research Association, the American Psychological Association, and the National Council on Measurement in Education. Despite its importance, this concept has been scarcely used in epidemiology and public health. Consequently, this methodological note aims to explain the concept of equity in testing and to provide tools and indications to detect and solve their inequitable use.     

Practices to support co-design processes: A case-study of co-designing a program for children with parents with a mental health problem in the Austrian region of Tyrol

Forms of collaborative knowledge production, such as community-academic partnerships (CAP), have been increasingly used in health care. However, instructions on how to deliver such processes are lacking. We aim to identify practice ingredients for one element within a CAP, a 6-month co-design process, during which 26 community- and 13 research-partners collaboratively designed an intervention programme for children whose parent have a mental illness. Using 22 published facilitating and hindering factors for CAP as the analytical framework, eight community-partners reflected on the activities which took place during the co-design process. From a qualitative content analysis of the data, we distilled essential practices for each CAP factor. Ten community- and eight research-partners revised the results and co-authored this article. We identified 36 practices across the 22 CAP facilitating or hindering factors. Most practices address more than one factor. Many practices relate to workshop design, facilitation methods, and relationship building. Most practices were identified for facilitating ‘trust among partners’, ‘shared visions, goals and/or missions’, ‘effective/frequent communication’, and ‘well-structured meetings’. Fewer practices were observed for ‘effective conflict resolution’, ‘positive community impact’ and for avoiding ‘excessive funding pressure/control struggles’ and ‘high burden of activities’. Co-designing a programme for mental healthcare is a challenging process that requires skills in process management and communication. We provide practice steps for delivering co-design activities. However, practitioners may have to adapt them to different cultural contexts. Further research is needed to analyse whether co-writing with community-partners results in a better research output and benefits for participants.