Sialylated glycoproteins and sialyltransferases in digestive cancers: Mechanisms, diagnostic biomarkers, and therapeutic targets.

Sialic acid (SA), as the ultimate epitope of polysaccharides, can act as a cap at the end of polysaccharide chains to prevent their overextension. Sialylation is the enzymatic process of transferring SA residues onto polysaccharides and is catalyzed by a group of enzymes known as sialyltransferases (SiaTs). It is noteworthy that the sialylation level of glycoproteins is significantly altered when digestive cancer occurs. And this alteration exhibits a close correlation with the progression of these cancers. In this review, from the perspective of altered SiaTs expression levels and changed glycoprotein sialylation patterns, we summarize the pathogenesis of gastric cancer (GC), colorectal cancer (CRC), pancreatic ductal adenocarcinoma (PDAC), and hepatocellular carcinoma (HCC). Furthermore, we propose potential early diagnostic biomarkers and prognostic indicators for different digestive cancers. Finally, we summarize the therapeutic value of sialylation in digestive system cancers.

Crosstalk between ubiquitin ligases and ncRNAs drives cardiovascular disease progression.

Cardiovascular diseases (CVDs) are multifactorial chronic diseases and have the highest rates of morbidity and mortality worldwide. The ubiquitin-proteasome system (UPS) plays a crucial role in posttranslational modification and quality control of proteins, maintaining intracellular homeostasis via degradation of misfolded, short-lived, or nonfunctional regulatory proteins. Noncoding RNAs (ncRNAs, such as microRNAs, long noncoding RNAs, circular RNAs and small interfering RNAs) serve as epigenetic factors and directly or indirectly participate in various physiological and pathological processes. NcRNAs that regulate ubiquitination or are regulated by the UPS are involved in the execution of target protein stability. The cross-linked relationship between the UPS, ncRNAs and CVDs has drawn researchers' attention. Herein, we provide an update on recent developments and perspectives on how the crosstalk of the UPS and ncRNAs affects the pathological mechanisms of CVDs, particularly myocardial ischemia/reperfusion injury, myocardial infarction, cardiomyopathy, heart failure, atherosclerosis, hypertension, and ischemic stroke. In addition, we further envision that RNA interference or ncRNA mimics or inhibitors targeting the UPS can potentially be used as therapeutic tools and strategies.

Integrative analysis of DNA methylome and transcriptome reveals epigenetic regulation of bisphenols-induced cardiomyocyte hypertrophy.

Cardiac hypertrophy, a kind of cardiomyopathic abnormality, might trigger heart contractile and diastolic dysfunction, and even heart failure. Currently, bisphenols (BPs) including bisphenol A (BPA), and its alternatives bisphenol AF (BPAF), bisphenol F (BPF) and bisphenol S (BPS) are ubiquitously applied in various products and potentially possess high cardiovascular risks for humans. However, the substantial experimental evidences of BPs on heart function, and their structure-related effects on cardiomyocyte hypertrophy are still urgently needed. DNA methylation, a typical epigenetics, play key roles in BPs-induced transcription dysregulation, thereby affecting human health including cardiovascular system. Thus, in this study, we performed RNA-seq and reduced representation bisulfite sequencing (RRBS) to profile the landscapes of BPs-induced cardiotoxicity and to determine the key roles of DNA methylation in the transcription. Further, the capabilities of three BPA analogues, together with BPA, in impacting heart function and changing DNA methylation and transcription were compared. We concluded that similar to BPA, BPAF, BPF and BPS exposure deteriorated heart function in a mouse model, and induced cardiomyocyte hypertrophy in a H9c2 cell line. BPAF, BPF and BPS all played BPA-like roles in both transcriptive and methylated hierarchies. Moreover, we validated the expression levels of four cardiomyocyte hypertrophy related candidate genes, Psmc1, Piptnm2, Maz and Dusp18, which were all upregulated and with DNA hypomethylation. The findings on the induction of BPA analogues on cardiomyocyte hypertrophy and DNA methylation revealed their potential detrimental risks in heart function of humans.

A review of the occurrence, metabolites and health risks of butylated hydroxyanisole (BHA).

Butylated hydroxyanisole (BHA) is mainly used as a food additive due to its antioxidant properties, which prevent or delay oxidation reactions and extend the storage life of products. The widespread use of BHA has led to its extensive presence in various environmental matrices and human tissues. Food intake is the main route of human exposure to BHA. Under different conditions, BHA can produce different metabolites, with tert-butyl hydroquinone (TBHQ) being one of the major products. Several studies have shown that BHA could cause thyroid system damage, metabolic and growth disorders, neurotoxicity, and carcinogenesis. Mechanisms such as endocrine disruption, genotoxicity, disturbances of energy metabolism, reactive oxygen species (ROS) production, signaling pathways, and imbalances in calcium homeostasis appear to be associated with the toxic effects of BHA. Avoiding the toxic effects of BHA to the maximum extent possible is a top priority. Finding safe, non-toxic and environmentally friendly alternatives to BHA should be the focus of subsequent research. In all, this review summarized the current situation related to BHA and might make recommendations for future research directions. © 2023 Society of Chemical Industry.

A review of cardiovascular effects and underlying mechanisms of legacy and emerging per- and polyfluoroalkyl substances (PFAS).

Cardiovascular disease (CVD) poses the leading threats to human health and life, and their occurrence and severity are associated with exposure to environmental pollutants. Per- and polyfluoroalkyl substances (PFAS), a group of widely used industrial chemicals, are characterized by persistence, long-distance migration, bioaccumulation, and toxicity. Some PFAS, particularly perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA) and perfluorohexanesulfonic acid (PFHxS), have been banned, leaving only legacy exposure to the environment and human body, while a number of novel PFAS alternatives have emerged and raised concerns, such as polyfluoroalkyl ether sulfonic and carboxylic acid (PFESA and PFECA) and sodium p-perfluorous nonenoxybenzene sulfonate (OBS). Overall, this review systematically elucidated the adverse cardiovascular (CV) effects of legacy and emerging PFAS, emphasized the dose/concentration-dependent, time-dependent, carbon chain length-dependent, sex-specific, and coexposure effects, and discussed the underlying mechanisms and possible prevention and treatment. Extensive epidemiological and laboratory evidence suggests that accumulated serum levels of legacy PFAS possibly contribute to an increased risk of CVD and its subclinical course, such as cardiac toxicity, vascular disorder, hypertension, and dyslipidemia. The underlying biological mechanisms may include oxidative stress, signaling pathway disturbance, lipid metabolism disturbance, and so on. Various emerging alternatives to PFAS also play increasingly prominent toxic roles in CV outcomes that are milder, similar to, or more severe than legacy PFAS. Future research is recommended to conduct more in-depth CV toxicity assessments of legacy and emerging PFAS and explore more effective surveillance, prevention, and treatment strategies, accordingly.

The critical roles of m6A RNA methylation in lung cancer: from mechanism to prognosis and therapy.

Lung cancer, a highly malignant disease, greatly affects patients' quality of life. N6-methyladenosine (m6A) is one of the most common posttranscriptional modifications of various RNAs, including mRNAs and ncRNAs. Emerging studies have demonstrated that m6A participates in normal physiological processes and that its dysregulation is involved in many diseases, especially pulmonary tumorigenesis and progression. Among these, regulators including m6A writers, readers and erasers mediate m6A modification of lung cancer-related molecular RNAs to regulate their expression. Furthermore, the imbalance of this regulatory effect adversely affects signalling pathways related to lung cancer cell proliferation, invasion, metastasis and other biological behaviours. Based on the close association between m6A and lung cancer, various prognostic risk models have been established and novel drugs have been developed. Overall, this review comprehensively elaborates the mechanism of m6A regulation in the development of lung cancer, suggesting its potential for clinical application in the therapy and prognostic assessment of lung cancer.

Unique regulatory roles of ncRNAs changed by PM2.5 in human diseases.

PM2.5 is a type of particulate matter with an aerodynamic diameter smaller than 2.5 µm, and exposure to PM2.5 can adversely damage human health. PM2.5 may impair health through oxidative stress, inflammatory reactions, immune function alterations and chromosome or DNA damage. Through increasing in-depth studies, researchers have found that noncoding RNAs (ncRNAs), particularly microRNAs (miRNAs), circular RNAs (circRNAs) as well as long noncoding RNAs (lncRNAs), might play significant roles in PM2.5-related human diseases via some of the abovementioned mechanisms. Therefore, in this review, we mainly discuss the regulatory function of ncRNAs altered by PM2.5 in human diseases and summarize the potential molecular mechanisms. The findings reveal that these ncRNAs might induce or promote diseases via inflammation, the oxidative stress response, cell autophagy, apoptosis, cell junction damage, altered cell proliferation, malignant cell transformation, disruption of synaptic function and abnormalities in the differentiation and status of immune cells. Moreover, according to a bioinformatics analysis, the altered expression of potential genes caused by these ncRNAs might be related to the development of some human diseases. Furthermore, some ncRNAs, including lncRNAs, miRNAs and circRNAs, or processes in which they are involved may be used as biomarkers for relevant diseases and potential targets to prevent these diseases. Additionally, we performed a meta-analysis to identify more promising diagnostic ncRNAs as biomarkers for related diseases.

Preliminary Study on the Protective Effects and Molecular Mechanism of Procyanidins against PFOS-Induced Glucose-Stimulated Insulin Secretion Impairment in INS-1 Cells.

This study aimed to investigate the effects of perfluorooctanesulfonic acid (PFOS) exposure on glucose-stimulated insulin secretion (GSIS) of rat insulinoma (INS-1) cells and the potential protective effects of procyanidins (PC). The effects of PFOS and/or PC on GSIS of INS-1 cells were investigated after 48 h of exposure (protein level: insulin; gene level: glucose transporter 2 (Glut2), glucokinase (Gck), and insulin). Subsequently, the effects of exposure on the intracellular reactive oxygen species (ROS) activity were measured. Compared to the control group, PFOS exposure (12.5, 25, and 50 µM) for 48 h had no significant effect on the viability of INS-1 cells. PFOS exposure (50 µM) could reduce the level of insulin secretion and reduce the relative mRNA expression levels of Glut2, Gck, and insulin. It is worth noting that PC could partially reverse the damaging effect caused by PFOS. Significantly, there was an increase in ROS after exposure to PFOS and a decline after PC intervention. PFOS could affect the normal physiological function of GSIS in INS-1 cells. PC, a plant natural product, could effectively alleviate the damage caused by PFOS by inhibiting ROS activity.

Exosomal noncoding RNAs in central nervous system diseases: biological functions and potential clinical applications.

Central nervous system (CNS) disease is a general term for a series of complex and diverse diseases, including Alzheimer's disease (AD), Parkinson's disease (PD), multiple sclerosis (MS), CNS tumors, stroke, epilepsy, and amyotrophic lateral sclerosis (ALS). Interneuron and neuron-glia cells communicate with each other through their homeostatic microenvironment. Exosomes in the microenvironment have crucial impacts on interneuron and neuron-glia cells by transferring their contents, such as proteins, lipids, and ncRNAs, constituting a novel form of cell-to-cell interaction and communication. Exosomal noncoding RNAs (ncRNAs), including microRNAs (miRNAs), long noncoding RNAs (lncRNAs), circular RNAs (circRNAs), and PIWI-interacting RNAs (piRNAs), regulate physiological functions and maintain CNS homeostasis. Exosomes are regarded as extracellular messengers that transfer ncRNAs between neurons and body fluids due to their ability to cross the blood-brain barrier. This review aims to summarize the current understanding of exosomal ncRNAs in CNS diseases, including prospective diagnostic biomarkers, pathological regulators, therapeutic strategies and clinical applications. We also provide an all-sided discussion of the comparison with some similar CNS diseases and the main limitations and challenges for exosomal ncRNAs in clinical applications.

Adverse cardiovascular effects and potential molecular mechanisms of DEHP and its metabolites-A review.

Currently, cardiovascular disease (CVD) is a health hazard that is associated with progressive deterioration upon exposure to environmental pollutants. Di(2-ethylhexyl) phthalate (DEHP) has been one of the focuses of emerging concern due to its ubiquitous nature and its toxicity to the cardiovascular (CV) system. DEHP has been noted as a causative risk factor or a risk indicator for the initiation and augment of CVDs. DEHP represents a precursor that contributes to the pathogenesis of CVDs through its active metabolites, which mainly include mono (2-ethylhexyl) phthalate (MEHP). Herein, we systematically presented the association between DEHP and its metabolites and adverse CV outcomes and discussed the corresponding effects, underlying mechanisms and possibly interventions. Epidemiological and experimental evidence has suggested that DEHP and its metabolites have significant impacts on processes and factors involved in CVD, such as cardiac developmental toxicity, cardiac injury and apoptosis, cardiac arrhythmogenesis, cardiac metabolic disorders, vascular structural damage, atherogenesis, coronary heart disease and hypertension. DNA methylation, PPAR-related pathways, oxidative stress and inflammation, Ca2+ homeostasis disturbance may pinpoint the relevant mechanisms. The preventive and therapeutic measures are potentially related with P-glycoprotein, heat-shock proteins, some antioxidants, curcumin, apigenin, ß-thujaplicin, glucagon-like peptide-1 receptor agonists and Ang-converting enzyme inhibitors and so on. Promisingly, future investigations should aid in thoroughly assessing the causal relationship and molecular interactions between CVD and DEHP and its metabolites and explore feasible prevention and treatment measures accordingly.

The regulatory function of piRNA/PIWI complex in cancer and other human diseases: The role of DNA methylation.

Piwi-interacting RNAs (piRNAs) are a class of short chain noncoding RNAs that are constituted by 26-30 nucleotides (nt) and can couple with PIWI protein family. piRNAs were initially described in germline cells and are believed to be critical regulators of the maintenance of reproductive line. Increasing evidence has extended our perspectives on the biological significance of piRNAs and indicated that they could still affect somatic gene expression through DNA methylation, chromatin modification and transposon silencing, etc. Many studies have revealed that the dysregulation of piRNAs might contribute to diverse diseases through epigenetic changes represented by DNA methylation and chromatin modification. In this review, we summarized piRNA/PIWI protein-mediated DNA methylation regulation mechanisms and methylation changes caused by piRNA/PIWI proteins in different diseases, especially cancers. Since DNA methylation and inhibitory chromatin marks represented by histone H3 lysine 9 (H3K9) methylation frequently cooperate to silence genomic regions, we also included methylation in chromatin modification within this discussion. Furthermore, we discussed the potential clinical applications of piRNAs as a new type promising biomarkers for cancer diagnosis, as well as the significance of piRNA/PIWI protein-associated methylation changes in treatment, providing disparate insights into the potential applications of them.

Ferroptosis in Cancer Progression: Role of Noncoding RNAs.

Ferroptosis is a novel form of programmed cell death, and it is characterized by iron-dependent oxidative damage, lipid peroxidation and reactive oxygen species accumulation. Notable studies have revealed that ferroptosis plays vital roles in tumor occurrence and that abundant ferroptosis in cells can inhibit tumor progression. Recently, some noncoding RNAs (ncRNAs), particularly microRNAs, long noncoding RNAs, and circular RNAs, have been shown to be involved in biological processes of ferroptosis, thus affecting cancer growth. However, the definite regulatory mechanism of this phenomenon is still unclear. To clarify this issue, increasing studies have focused on the regulatory roles of ncRNAs in the initiation and development of ferroptosis and the role of ferroptosis in progression of various cancers, such as lung, liver, and breast cancers. In this review, we systematically summarized the relationship between ferroptosis-associated ncRNAs and cancer progression. Moreover, additional evidence is needed to identify the role of ferroptosis-related ncRNAs in cancer progression. This review will help us to understand the roles of ncRNAs in ferroptosis and cancer progression and may provide new ideas for exploring novel diagnostic and therapeutic biomarkers for cancer in the future.

Emerging roles of circRNAs in the pathological process of myocardial infarction.

Myocardial infarction (MI) is defined as cardiomyocyte death in a clinical context consistent with ischemic insult. MI remains one of the leading causes of morbidity and mortality worldwide. Although there are a number of effective clinical methods for the diagnosis and treatment of MI, further investigation of novel biomarkers and molecular therapeutic targets is required. Circular RNAs (circRNAs), novel non-coding RNAs, have been reported to function mainly by acting as microRNA (miRNA) sponges or binding to RNA-binding proteins (RBPs). The circRNA-miRNA-mRNA (protein) regulatory pathway regulates gene expression and affects the pathological mechanisms of various diseases. Undoubtedly, a more comprehensive understanding of the relationship between MI and circRNA will lay the foundation for the development of circRNA-based diagnostic and therapeutic strategies for MI. Therefore, this review summarizes the pathophysiological process of MI and various approaches to measure circRNA levels in MI patients, tissues, and cells; highlights the significance of circRNAs in the regulation MI pathogenesis and development; and provides potential clinical insight for the diagnosis, prognosis, and treatment of MI.

Emerging Functions and Clinical Applications of Exosomal ncRNAs in Ovarian Cancer.

Ovarian cancer (OC) is one of the deadliest gynecological malignancies worldwide and has a high mortality rate. Its dismal prognosis is closely related to late diagnosis and drug resistance. Exosomes are a novel means of intercellular communication that are involved in the genesis and development of tumors by delivering a variety of biologically active molecules, including proteins, lipids, and nucleic acids. As an important component, noncoding RNAs (ncRNAs) are selectively enriched in exosomes and participate in the regulation of specific aspects of OC development, such as proliferation, invasion, metastasis, angiogenesis, immune escape, and treatment resistance. Therefore, strategies that specifically target exosomal ncRNAs may be attractive therapeutic options. Exosomes are readily available in almost all types of human biological fluids and are biocompatible, making them promising biomarkers of OC as well as targets for therapeutic applications. In this review, we briefly summarize the biology of exosomes, the function of exosomal ncRNAs in OC development, and their potential clinical applications as biomarkers and therapeutic tools. Ideally, exosomal ncRNAs will become increasingly valuable in the diagnosis and treatment of OC in the near future.

[Prevalence of malocclusion among 1022 Kazak junior school students: an epidemiological study].

PURPOSE: This study provided baseline data for oral public health though epidemiological survey to investigate the prevalence of malocclusion and the relationship with caries in Kazak junior school students in Xinjiang Aletai district, China. METHODS: Using stratified and cluster random sampling, 1 022 Kazak junior school students in Aletai district were chosen. According to the standard of Angle's classification and individual normal occlusion, a full clinical examination was carried out. The results were statistically analyzed by SAS JMP 10.0. RESULTS: Of all 1 022 subjects, the prevalence of malocclusion was 43.64%. Among them there were 215 males (43.97%) and 231 females (43.34%). The composition ratios of Class I, Class II and Class III malocclusion were 30.92%，3.42% and 9.30%, respectively. The malocclusion prevalence in urban was 44.56%, and 43.06% in rural areas. There was no significant difference between them. Among children with malocclusion, crowding of dentition was the majority, and the others in turn were abnormal space of anterior teeth, deep overjet, deep overbite, cross jet, and open bite. The prevalence of caries was 59.49%, and DMFT was 1.382. Students who had caries with malocclusion was 1.54 times more than those who did not have caries. CONCLUSIONS: Compared with other studies, the prevalence of malocclusion in Xinjiang Aletai district is not high. The incidence of malocclusion is closely related to caries.

The emerging function and clinical significance of circRNAs in Thyroid Cancer and Autoimmune Thyroid Diseases.

Thyroid cancer (TC) is one of the most common malignant tumors, with high morbidity and mortality rates worldwide. The incidence of TC, especially that of papillary thyroid carcinoma (PTC); has increased rapidly in recent decades. Autoimmune thyroid disease (AITD) is closely related to TC and has an estimated prevalence of 5%. Thus, it is becoming increasingly important to identify potential diagnostic biomarkers and therapeutic targets for TC and AITD. Circular RNAs (circRNAs) are a class of non-coding RNAs with covalently bonded circular structures that lack 5'-3' polarity and polyadenylated tails. Several circRNAs play crucial roles in the development of various diseases, including TC and AITD, and could be important new biomarkers and/or targets for the diagnosis and therapy of such disorders. Although there are four subtypes of TC, research on circRNA has largely focused on its connection to PTC. Therefore, this review mainly summarizes the relationships between circRNAs and PTC and AITD, including the molecular mechanisms underlying these relationships. In particular, the functions of "miRNA sponges" and their interactions with proteins and RNA are discussed. The possible targeting of circRNAs for the prevention, diagnosis, and treatment of TC and AITD is also described. CircRNAs could be potential biomarkers of TC and AITD, although validation will be required before they can be implemented in clinical practice.

Insights into the regulatory role of Plexin D1 signalling in cardiovascular development and diseases.

Plexin D1 (PLXND1), which was previously thought to mediate semaphorin signalling, belongs to the Plexin family of transmembrane proteins. PLXND1 cooperates mostly with the coreceptor neuropilin and participates in many aspects of axonal guidance. PLXND1 can also act as both a tumour promoter and a tumour suppressor. Emerging evidence suggests that mutations in PLXND1 or Semaphorin 3E, the canonical ligand of PLXND1, can lead to serious cardiovascular diseases, such as congenital heart defects, CHARGE syndrome and systemic sclerosis. Upon ligand binding, PLXND1 can act as a GTPase-activating protein (GAP) and modulate integrin-mediated cell adhesion, cytoskeletal dynamics and cell migration. These effects may play regulatory roles in the development of the cardiovascular system and disease. The cardiovascular effects of PLXND1 signalling have gradually been elucidated. PLXND1 was recently shown to detect physical forces and translate them into intracellular biochemical signals in the context of atherosclerosis. Therefore, the role of PLXND1 in cardiovascular development and diseases is gaining research interest because of its potential as a biomarker and therapeutic target. In this review, we describe the cardiac effects, vascular effects and possible molecular mechanisms of PLXND1 signalling.

Pregnancy outcomes of infertile women with ultrasound-diagnosed adenomyosis for in vitro fertilization and frozen-thawed embryo transfer.

OBJECTIVE: This study aimed to investigate the effect of ultrasound-diagnosed adenomyosis on assisted pregnancy outcomes, i.e., in vitro fertilization-embryo transfer (IVF-ET). METHODS: This was a retrospective cohort study of 18,568 women who had received their first frozen-thawed ET cycle in Center of Reproductive Medicine, Children's Hospital of Shanxi and Women Health Center of Shanxi and the Reproductive Medicine Center of Tianjin Central Obstetrics and Gynecology Hospital from January 2014 to May 2019. A total of 5,087 patients met the inclusion and exclusion criteria, and they were divided into two groups: adenomyosis with tubal factor infertility (study group, n = 193) and only tubal factor infertility (control group, n = 4894). After a 1:1 propensity score match (caliper value = 0.005), 360 cases were matched in the end. RESULT: There was no statistical difference in the embryo implantation rate, clinical pregnancy rate, or multiple pregnancy rate between the two groups (28.4% vs. 31.7%, 42.2% vs. 42.8%, and 11.7% vs. 12.8%, respectively; P > 0.05). However, the early miscarriage rate in the adenomyosis group was significantly higher than that in the control group (13.3% vs. 5.6%, respectively; P = 0.012). The live birth rate was 22.8% in the women with adenomyosis and was observed to be significantly lower than 33.3% in the control group (P = 0.026). The patients with adenomyosis had a higher incidence of pregnancy complications than those without (4.4% vs. 0.6%, respectively; P = 0.018), but the neonatal birth weight was not related to adenomyosis. CONCLUSION: Women with adenomyosis should be treated as being at high risk of early miscarriage. However, maternal adenomyosis has no effect on the birth weight of the newborn.

Cardiovascular toxicity and mechanism of bisphenol A and emerging risk of bisphenol S.

Epidemiological and animal studies indicate that increased exposure to bisphenol A (BPA) induces various human cardiovascular diseases (CVDs), including myocardial infarction, arrhythmias, dilated cardiomyopathy, atherosclerosis, and hypertension. Bisphenol S (BPS), an alternative to BPA, is increasingly present in various consumer products and human bodies worldwide. Recently, emerging evidence has shown that BPS might be related to cardiovascular disorders. In this review, we present striking evidence of the correlation between BPA exposure and various CVDs, and show that a nonmonotonic dose-response curve (NMDRC) was common in studies of the CV effects of BPA in vivo. The CV impairment induced by low doses of BPA should be highlighted, especially during developmental exposure or during coexposure with other risk factors. Furthermore, we explored the possible underlying mechanisms of these effects-particularly nuclear receptor signaling, ion channels, and epigenetic mechanisms-and the possible participation of lipid metabolism, oxidative stress and cell signaling. As the potential risks of BPA exposure in humans are still noteworthy, studies of BPA in CVDs should be strengthened, especially with respect to the mechanisms, prevention and treatment. Moreover, the potential CV risk of BPS reported by in vivo studies calls for immediate epidemiological investigations and animal studies to reveal the relationships of BPS and other BPA alternatives with human CVDs.

Comparison the sensitivity of amphibian metamorphosis assays with NF 48 stage and NF 51 stage Xenopus laevis tadpoles.

The amphibian metamorphosis assay (AMA) was proposed by the Organization for Economic Cooperation and Development (OECD) to screen thyroid disruptors of vertebrate species. The general experimental design of the AMA exposes Nieuwkoop and Faber (NF) stage 51 Xenopus laevis tadpoles to test chemical concentrations for 21 d. However, recent studies demonstrated that thyroid gland began to function after NF stage 45 in X. laevis. Thus, in this study, we initiated exposure with NF stage 48 tadpoles when the thyroid gland is still in a preliminary development period, to compare the sensitivity of the AMA with NF 48 stage and NF 51 stage tadpoles. Further, the application and sensitivity of the optimized AMA were evaluated and validated by two known thyroid toxicants methimazole (MMI) and sodium perchlorate (SP). The observational endpoints are developmental stage, hind limb length (HLL), snout-vent length (SVL), wet weight, and daily observations of mortality. The results were as follows. Although the sensitivity to endpoint of growth, such as wet weight and SVL was similar between the two assays, our optimized AMA detected delaying effects of 1 mg/L MMI and 32 µg/L SP on metamorphosis development both on day 7 and at test termination, which were lower than those in AMA. Additionally, it is easier to get a large number of animals at NF stage 48 than NF stage 51 in a short time. Thus, it is suggested that the NF stage 48 tadpoles might be applied to the AMA for efficiently screening the thyroid-active substances.