Polystyrene microplastics enhance microcystin-LR-induced cardiovascular toxicity and oxidative stress in zebrafish embryos.

The health risks associated with combined exposure to microplastics (MPs) and cyanobacteria toxins have gained increasing attention due to the large-scale prevalence of cyanobacterial blooms and accumulation of MPs in aquatic environments. Therefore, we explored the cardiovascular toxic effects of microcystin-LR (MC-LR, 1, 10, 100 µg/L) in the presence of 5 µm polystyrene microplastics (PS-MPs, 100 µg/L) and 80 nm polystyrene nanoplastics (PS-NPs, 100 µg/L) in zebrafish models. Embryos were exposed to certain PS-MPs and PS-NPs conditions in water between 3 h post-fertilization (hpf) and 168 hpf. Compared to MC-LR alone, a significant decrease in heart rate was observed as well as notable pericardial edema in the MC-LR + PS-MPs/NPs groups. At the same time, sinus venosus and bulbus arteriosus (SV-BA) distances were significantly increased. Furthermore, the addition of PS-MPs/NPs caused thrombosis in the caudal vein and more severe vascular damage in zebrafish larvae compared to MC-LR alone. Our findings revealed that combined exposure to PS-NPs and MC-LR could significantly decreased the expression of genes associated with cardiovascular development (myh6, nkx2.5, tnnt2a, and vegfaa), ATPase (atp1a3b, atp1b2b, atp2a1l, atp2b1a, and atp2b4), and the calcium channel (cacna1ab and ryr2a) compared to exposure to MC-LR alone. In addition, co-exposure with PS-MPs/NPs exacerbated the MC-LR-induced reactive oxygen species (ROS) production, as well as the ROS-stimulated apoptosis and heightened inflammation. We also discovered that astaxanthin (ASTA) treatment partially attenuated these cardiovascular toxic effects. Our findings confirm that exposure to MC-LR and PS-MPs/NPs affects cardiovascular development through calcium signaling interference and ROS-induced cardiovascular cell apoptosis. This study highlights the potential environmental risks of the co-existence of MC-LR and PS-MPs/NPs for fetal health, particularly cardiovascular development.

Microcystin-LR induced transgenerational effects of thyroid disruption in zebrafish offspring by endoplasmic reticulum stress-mediated thyroglobulin accumulation and apoptosis.

MC-LR can interfere with thyroid function in fish, but the underlying mechanism is still unclear. Current study focuses to study the intergenerational inheritance of MC-LR-induced thyroid toxicity in zebrafish and in rat thyroid cells. In vivo experiments, adult female zebrafish (F0) were exposed to MC-LR (0, 5, and 25 µg/L) for 90 days and mated with male zebrafish without MC-LR exposure to generate F1 generation. F1 embryos were allowed to develop normally to 7 days post-fertilization (dpf) in clear water. In the F0 generation, MC-LR induced disturbance of the hypothalamic-pituitary-thyroid (HPT) axis, leading to a decrease in the production of thyroid hormones. Maternal MC-LR exposure also induced growth inhibition by altering thyroid hormones (THs) homeostasis and interfering with thyroid metabolism and development in F1 offspring. Mechanistically, MC-LR caused excessive accumulation of ROS and induced ER stress that further lead to activation of UPR in the F0 and F1 offspring of zebrafish. Interestingly, our findings suggested that MC-LR exposure hampered thyroglobulin turnover by triggering IRE1 and PERK pathway in zebrafish and FRTL-5 thyroid cells, thus disturbing the thyroid endocrine system and contributing to the thyroid toxicity from maternal to its F1 offspring of zebrafish. Particularly, inhibition of the IRE1 pathway by siRNA could alleviate thyroid development injury induced by MC-LR in FRTL-5 cells. In addition, MC-LR induced thyroid cell apoptosis by triggering ER stress. Taken together, our results demonstrated that maternal MC-LR exposure causes thyroid endocrine disruption by ER stress contributing to transgenerational effects in zebrafish offspring.

Microcystin-leucine-arginine affects brain gene expression programs and behaviors of offspring through paternal epigenetic information.

Microcystin-leucine-arginine (MC-LR) adversely affects male reproduction and interferes with the development of the offspring. Here, we establish a zebrafish (Danio rerio) model to understand the cross-generational effects of MC-LR in a male-lineage transmission pattern. F0 embryos were reared in water containing MC-LR (0, 5, and 25 µg/L) for 90 days and the developmental indices of F1 and F2 embryos were then measured with no MC-LR treatment. The results show that paternal MC-LR exposure reduced the hatching rate, heart rate and body weight in F1 and F2 generations. Global DNA methylation significantly increased in sperm and testes with the elevation expressions of DNA methyltransferases. Meanwhile, DNA methylation of brain-derived neurotrophic factor (bdnf) promoter was increased in sperm after paternal MC-LR exposure. Subsequently, increased DNA methylation of bdnf promoter and decreased gene expression of bdnf in the brain of F1 male zebrafish were detected. F1 offspring born to F0 males exhibit the depression of BDNF/AKT/CREB pathway and recapitulate these paternal neurodevelopment phenotypes in F2 offspring. In addition, the DNA methylations of dio3b and gad1b promoters were decreased and gene expressions of gad1b and dio3b were increased, accompanied with neurotransmitter disturbances in the brain of F1 male zebrafish after paternal MC-LR exposure. These data revealed that MC-LR displays a potential epigenetic impact on the germ line, reprogramming the epigenetic and transcriptional regulation of brain development, and contributing to aberrant expression of neurodevelopment-related genes and behavior disorders.

Pharmacokinetics and Pharmacodynamics of Sacubitril/Valsartan in Maintenance Hemodialysis Patients with Heart Failure.

BACKGROUND: Heart failure (HF) is one of the main comorbidities in patients receiving maintenance hemodialysis (HD). Sacubitril/valsartan (SAC/VAL) is widely used in HF patients with reduced ejection fraction (HFrEF) or HF mid-range ejection fraction (HFmrEF). However, the pharmacokinetic (PK) and pharmacodynamic properties of SAC/VAL in HD patients with HF remain uncertain. OBJECTIVES: This study aimed to analyze the efficacy and PK properties of SAC/VAL in HD patients with HFrEF or HFmrEF. METHODS: HD patients with HFrEF or HFmrEF were treated with SAC/VAL 50 or 100 mg twice a day (BID) and the concentrations of valsartan and LBQ657 (active metabolite of SAC) were determined by high-performance liquid chromatography-tandem mass spectrometry during HD and on the days between HD sessions (interval days). N-terminal-pro B-type natriuretic peptide and high-sensitivity troponin T were measured, and left ventricular ejection fraction (LVEF) was evaluated by echocardiography. RESULTS: The mean maximum plasma concentrations (Cmax) of LBQ657 and VAL on the interval days were 15.46 ± 6.01 and 2.57 ± 1.23 mg/L, respectively. Compared with previous values in patients with severe renal impairment and healthy volunteers, these levels both remained within the safe concentration ranges during treatment with SAC/VAL 100 mg BID. Moreover, SAC/VAL significantly improved LVEF in HD patients with HFrEF or HFmrEF (p < 0.05). CONCLUSIONS: HD did not remove the SAC metabolite LBQ657 or VAL in patients with HF. However, SAC/VAL 100 mg BID was safe and effective in patients undergoing HD.

Treatment of Uremic Tumoral Calcinosis in Maintenance Hemodialysis Patients.

BACKGROUND/AIMS: Uremic tumoral calcinosis (UTC) is a rare disease with metastatic tissue calcification in maintenance hemodialysis (HD) patients. However, limited data are available on the treatment of UTC in HD patients. This article mainly discusses the diagnostic findings and efficacy of treatment on HD patients with UTC. METHODS: A retrospective analysis was conducted based on the data of 13 cases of UTC, including their clinical features, biochemical indicators, imaging findings, diagnosis, therapeutic methods, and follow-up results. Parathyroidectomy (PTX) or drug treatment was determined based on intact parathyroid hormone (iPTH) levels and clinical symptoms. RESULTS: All 13 patients were diagnosed as UTC definitely by imaging examination. The predominant areas involved were the buttocks (4 cases, 30.77%), shoulders (4 cases, 30.77%), and elbows (3 cases, 23.08%). Based on the levels of iPTH, cases were categorized into 2 different groups: PTX treatment group was associated with high levels of iPTH, while drug treatment group (lanthanum carbonate or sevelamer with sodium thiosulfate) was associated with lower iPTH levels. After PTX treatment, there was a significant decrease in serum iPTH, calcium (Ca), phosphate (P), and alkaline phosphatase levels (p < 0.05). In drug treatment group, the serum p levels were decreased significantly, along with a finding that hemoglobin levels were increased (p < 0.05). All the UTC had lessened or even disappeared after 4-6 months treatment. CONCLUSIONS: Although most UTC patients have an increased iPTH, a small number had lower iPTH levels. Based on iPTH levels and clinical symptoms, the patients were treated with PTX or drug therapy. With proper treatment, UTC disappeared without the need for surgery to remove calcinosis tissue.