Molecular mechanisms for fetal cardiac arrhythmia in intrahepatic cholestasis of pregnancy

Intrahepatic cholestasis in pregnancy (ICP) is characterized by raised serum bile acids which can cause fetal complications, including preterm labour and intrauterine death. The fetal death in ICP is not well understood. In this thesis, the mechanisms of bile-acid induced arrhythmia were studied extensively using in vitro models of the fetal heart. Addition of the bile acid taurocholate (TC) to cardiomyocytes led to a reduction in the rate and amplitude of contraction, dysregulation of beating and desynchronization of intracellular calcium release. The results obtained from both differentiated mouse and human embryonic stem cell-derived cardiomyocytes (ESC-CM) demonstrated that immature cardiomyocytes are more susceptible to TC-induced arrhythmias than more mature cardiomyocytes. Although classical hepatic bile acid transporters such as ntcp, mrp2 and mdr2 are expressed in neonatal rat cardiomyocytes, the results suggest that they are unlikely to play role in TC-induced arrhythmia. They also suggest that the bile acid nuclear receptor FXR is not involved as uptake of radioactively labelled TC into the cells is minimal and that there is no functional involvement of the classical hepatic FXR pathways in neonatal rat cardiomyocytes. Similarly, the membrane bile acid receptor TGR5 showed neither immunoreactivity nor functional effects in cardiomyocytes. TC binds to the muscarinic M2 receptor and serves as a partial agonist of this receptor in terms of receptor activation and its inhibitory effect on cAMP in neonatal rat cardiomyocytes. Inhibition of the M2 muscarinic receptor by antagonist and the knockdown of the receptor with siRNA completely abolished the negative effect of TC on cardiomyocyte contraction, calcium transient amplitude and synchronisation in small cell clusters. In conclusion, immature ESC-CMs are more susceptible to TC and this effect is lost as cells progress to more mature phenotypes. Moreover, the findings suggest the arrhythmogenic effect of TC in neonatal cardiomyocytes is mediated by the muscarinic M2 receptor. This mechanism might serve as a promising new therapeutic target for fetal arrhythmia

Removal of As(III) and As(V) from water using green, silica-based ceramic hollow fibre membranes via direct contact membrane distillation

Arsenite [As(III)] and arsenate [As(V)] removal by direct contact membrane distillation (DCMD) using novel hydrophobic green, silica-based ceramic hollow fibre membranes derived from agricultural rice husk was investigated in this work. The green ceramic hollow fibre membranes were prepared from amorphous (ASHFM) and crystalline (CSHFM) silica-based rice husk ash and modified to be hydrophobic via immersion fluoroalkylsilane (FAS) grafting of 1H,1H,2H,2H-perfluorodecyltriethoxysilane. Superhydrophobic contact angle values up to 157° and 161° were obtained for ASHFM and CSHFM, respectively. Remarkably, the membrane surface morphology mimicked a look-alike lotus-leaf structure with decrement in pore size after grafting via the silane agent for both membranes. The effect of arsenic pH (3–11), arsenic concentration (1–1000 ppm) and feed temperature (50–80 °C) were studied and it was found that feed temperature had a significant effect on the permeate flux. The hydrophobic CSHFM, with a flux of 50.4 kg m−2 h−1 for As(III) and 51.3 kg m−2 h−1 for As(V), was found to be the best of the tested membranes. In fact, this membrane can reject arsenic to the maximum contaminant level (MCL) limit of 10 ppb under any conditions, and no swelling mechanism of the membranes was observed after testing for 4 hours

Aloe emodin induces apoptosis in ER+-breast cancer cells; MCF-7 through IGF-1R signalling pathway

Two-third of breast cancer patients expressed estrogen receptors (ER)s and received endocrine treatment with established anti-estrogens such as tamoxifen. But the action and acquired resistance during treatment are largely unknown. In contrary, phytochemicals are more selective and less cytotoxic to normal cells. Accordingly, we found aloe emodin, an anthraquinone to inhibit the proliferation of ER+-breast cancer cells, MCF-7 with IC50 of 80 μM, but not affecting control breast cells, MCF-10A. Tamoxifen was non-selective to both cells with IC50 of 27 and 38 μM, respectively. Thus, we aimed to investigate the anti-proliferative mechanism of aloe emodin on MCF-7 and its underlying signalling compared to tamoxifen. Cells were treated separately with aloe emodin and tamoxifen at respective IC50 for 72 h. Apoptosis was determined using Annexin V-FITC/PI staining. The expression of insulin-like growth factor-1 receptor (IGF-1R), insulin-like growth factor binding protein (IGFBP)-2 and B-raf gene was investigated using QuantiGene 2.0 Plex assay. Paired-student t-test and ANOVA test were used to compare between untreated and treated cells on the measured parameters. Each treatment was conducted in triplicate and repeated three times. Significance was set at p<0.05. The presences of early and late apoptosis in MCF-7 were seen in both treatments. All target genes were down regulated. The anti-proliferation effect of aloe emodin on MCF-7 is similar with tamoxifen which mediates inhibition of IGF-1R signalling pathway. This suggests aloe emodin as a potential anti-cancer agent to be used in combined anti-estrogen therapy to enhance its efficacy in ER+-breast cancer treatment

Effects of bisphenol a on neonatal cardiomyocytes beating rate and morphology

Bisphenol A (BPA) has been utilised excessively at a global capacity of 2.9 billion kg/year. It is widely used in manufacturing polycarbonate polymers and epoxy resins. Hence, humans are potentially exposed to this chemical substance in their daily life. As a typical endocrine disruptor, BPA exhibits detectable hormone-like properties. Many studies have been linking BPA exposure in humans with the risk of developing cardiovascular disease, however the direct exposure of BPA on cardiomyocytes beating rates and morphology have not been entirely explored. Therefore, in this study, we aimed to investigate the effects of BPA on cells structure and function of neonatal rat cardiomyocytes culture. Cardiomyocytes were isolated from 0 to 2 days old newborn rats and treated with 0.001 to 100 µM concentration of BPA. All cardiomyocytes were subjected to immunostaining, beating frequency assessment assay, MTS assay and Scanning Electron microscopy (SEM). In immunostaining, cardiomyocytes showed positive staining for F-actin. This staining allows identification of the cells thus differentiate cardiomyocytes from other cell types. Significance effects of BPA on cardiomyocytes were observed in MTS assay (p<0.05) and beating rates (p<0.01). Significant reduction (48%-64%, ± 1.5280) was observed in beating rate of cardiomyocytes exposed to 0.1 to 100 µM of BPA. Meanwhile in MTS assay, significant reduction (54%, 0.067 ± 0.0026) in cell viability was observed in cells exposed to 0.1 µM of BPA only. Interestingly, under SEM, cardiomyocytes showed altered cell surface homogeneity after BPA exposure. Exposure of 0.1 to 100 µM BPA lead to flatten of cardiomyocytes cell surface and blurring of the cell borders. This study offers an in vitro evidence of BPA effects on cardiomyocytes morphology and beating rates, thus suggest the potential adverse effect of BPA exposure. However, further investigation would be required to understand how BPA effects normal cells morphology and beating rates of heart cells

Low concentration of Bisphenol a induces proliferation of gastric cancer cells, HGC-27

Bisphenol A, an endocrine disrupting compound that affects human homeostasis. Studies on BPA are focusing on the impact of BPA in reproductive function and brain development. However, the effect of BPA on gut especially gastric cells is not well explored. Gut is directly in contact with ingested BPA; therefore, we aimed to determine the effect of BPA exposure on gastric cells proliferation at safe recommended concentration. Human gastric cancer cells (HGC-27) were treated with BPA at different concentration (low: 10-9M, 10-7M; high10-5M, 10-4M) and time point (24 hr, 48 hr, 72 hr). Cell viability assays were determined using MTS assay. Cells were further stained with Alexa Fluor-635 (F-actin) and Fluorescein (Hif-1α) protein for immunocytofluorescence. Data were analysed using ANOVA (p<0.05, n≥3). Cells treated with 10-9M BPA showed significance increase of cell viability after 48 hr (Mean ±SEM; 146%±0.03, p=0.01) and 72 hr (113%±0.03, p=0.00) compared to 24 hr treatment (77%±0.11, p=0.002). Similarly, cell treated with 10-7M BPA showed a significance increase after 48 hr (141%±0.03, p=0.03) and 72 hr (190%±0.03, p=0.02) compared to 24 hr cells treated with 10-7M (88%±0.05, p=0.01) and untreated (100%±0.07). Lower concentration of BPA increases the condensation of F-actin in all HGC-27 cells. Meanwhile, translocation of Hif-1α protein were observed in all BPA-exposed cells. Findings of this study revealed that BPA induced proliferation and condensation of F-actin structure of gastric cancer cells at low concentration

Comparison of non-alcoholic fatty liver disease (NAFLD) model using diet-induced NAFLD mice with genetically modified mice

Prevalence of non-alcoholic fatty liver disease (NAFLD) is increasing steadily every year affecting all population both Western and Asian countries. The current treatments available for NAFLD are non-conclusive warranting newer effective pharmacological agents. Newly formulated agents require prior testing using animal models. However, in developing countries, these models are often costly. The possibility of using more affordable animal model in local settings should be investigated. In this study, ten Institute of Cancer Research (ICR) and seven B6.Cg-LepOb/J leptin-knockout (JAX) male mice were recruited. Five ICR and all JAX mice were subjected to high-fat diet (60% kcal fat) and remaining ICR mice were given standard diet (SD) for six weeks. Body weight and food intake were measured weekly while abdominal circumference, random blood glucose and liver span were measured at the end of the HFD study. Livers collected were subjected to histology assessment. Compared to ICR group, JAX group presented with significantly higher body weight (58 ± 0.72, p<0.05), larger body weight changes (16.57 ± 0.81, p<0.05), more HFD intake (197.14 ± 0.812, p<0.05) and larger abdominal circumference (11.79 ± 0.34: p<0.05). Liver from JAX group appeared with general steatosis and presentation of high-grade panacinar steatosis, low number of lobular inflammations and minimal fibrosis. Liver of ICR mice showed Zone 3 steatosis with high number of lobular inflammations without fibrosis. The NAFLD characteristics presented in JAX group suggested that B6.Cg-LepOb/J mice developed characteristics of NAFLD resembling human while ICR is suitable NAFLD model resembling human population resilient towards NAFLD

Fabrication and characterisation of superhydrophobic bio-ceramic hollow fibre membranes prepared from cow bone waste

Superhydrophobic membranes have great potential towards various application, especially for thermal-based membrane system such as membrane distillation. In this study, bioceramic hollow fibre membranes derived from cow bone waste were prepared by phase inversion/sintering method, followed by surface modification via immersion grafting with fluoroalkylsilane (FAS) agent. Interestingly, the grafting process led to the formation of hydroxyapatite nanorods, mimicking the unique structure of electrospun nanofiber membranes. The hydrophobicity of the modified membranes was assessed by measuring the water contact angle and showed excellent improvement from hydrophilic property to superhydrophobic with the highest value of 174° After the modification, the water entry pressure also improved from 0 to 1 bar. In addition, the presence of FAS agent on the membrane surface was observed using X-ray photoelectron spectroscopy (XPS). A correlation between pore size, porosity, and mechanical strength of the modified membrane was discussed; the increment of membrane pore size after grafting process is synonym to the dental erosion mechanism. The result indicates that the superhydrophobic bioceramic hollow fibre membranes derived from cow bone waste have significant potential to be developed for membrane distillation application in treating water and wastewater

Polysulfone hemodialysis membrane incorporated with Fe2O3 for enhanced removal of middle molecular weight uremic toxin

Removing middle molecular weight uremic toxin remains as one of the most challenging tasks in hemodialysis. Hence, in this study a high performance polysulfone (PSf) hemodialysis membrane was developed by incorporating iron oxide (Fe2O3) nanoparticles. The PSf/Fe2O3 hemodialysis membrane and pristine PSf membrane were prepared via dry-wet spinning process. The membranes were characterized by scanning electron microscopy, water contact angle, average pore size, and porosity measurements. The biocompatibility profiles of the membranes were also evaluated in terms of protein adsorption and blood coagulation time. Next, the performance of the membranes was determined by measuring pure water permeability (PWP), bovine serum albumin rejection, and removal of various solutes such as urea and lysozyme. The incorporation of Fe2O3 resulted in significant increment of the PWP from 40.74 L/m2/h/bar to 58.6 L/m2/h/bar, mainly due to the improved water transport properties of the membrane. Moreover, the percent removal of urea and lysozyme was reported to be 75.1% and 35.6%, respectively. PSf/Fe2O3 hemodialysis membrane is proven to have a bright prospect for enhanced blood purification process

High flux polysulfone braided hollow fiber membrane for wastewater treatment role of zinc oxide as hydrophilic enhancer

Incorporation of zinc oxide (ZnO) nanoparticles has played an important role on the improvement of unique membrane characterization and performance, most notably the hydrophilic modification of the membrane for higher pure water permeability. Additionally, the permeability of the membrane can be improved via introduction of braid support by reducing the thickness of the membrane separation layer. Moreover, the braided hollow fiber membrane (BHFM) is able to perform under higher pressure conditions compared to hollow fiber membranes. In this paper, hybrid polysulfone (PSf)/ZnO BHFMs were fabricated via phase inversion method. Hydrophilic 10 ± 1.8 nm polycrystalline ZnO nanoparticles synthesized via sol-gel method were incorporated on BHFM to improve the hydrophilicity and increase flux with constant rejection under high pressure and the effect of the ZnO loading on the membrane properties and performance were thoroughly studied. The fabricated BHFMs with 0.0, 0.5, 1.0 and 1.5 wt% of ZnO nanoparticles concentration were defined as BHFM1, BHFM2, BHFM3 and BHFM4 respectively. Scanning electron microscopy (SEM), contact angle, mechanical strength, flux performance, rejection with bovine serum albumin (BSA) and fouling of best performed membrane were conducted to achieve the target of this paper. The performance of these hybrid ZnO/PSf BHFMs were compared with neat PSf hollow fiber membrane (HFM) and previous studies. The findings from this research work shows that BHFM4 has the most desired properties for wastewater treatment application. The ZnO nanoparticles in BHFM4 have improved hydrophilicity from 108.79° to 71.02°, and thus BHFM4 has increased flux performance from 36.20 to 919.12 L/m2 h at 1.0 bar pressure and 193.48 to 1909.11 L/m2h at 4.0 bar pressure when compared with BHFM1. Constant BSA rejection rates (> 90%) were observed in all BHFMs. The improved hydrophilicity and pure flux performance with constant rejection rate in high pressure conditions illustrates the suitability of fabricated ZnO/PSf BHFMs in wastewater treatment applications

The impacts of intrauterine Bisphenol A exposure on pregnancy and expression of miRNAs related to heart development and diseases in animal model

This study aimed to examine the impact of BPA exposure on pregnancy and foetuses on cardiac tissues and the expression of cardiac microRNAs (miRNAs) related to heart development and diseases. Pregnancy is known to be the “critical windows” in determining the offspring physical and cells development in their life after birth. The increment of the risk of cardiovascular disease (CVD) in a later stage of life has been reported by few studies demonstrated from prenatal exposure of BPA. BPA has been shown to alter miRNAs expression profiles for organ development, regeneration and metabolic functions. These alterations have been associated with the risk of CVDs. However, the associations between pregnancy outcomes and miRNAs expression in cardiac of mother- and foetuses-exposed to BPA are still not entirely explored. In BPA-exposed pregnant rat groups, a significant weight gained was observed in comparison to control (p < 0.05). Interestingly, significant changes in systolic and diastolic blood pressure between the first and third trimester of BPA-exposed pregnant rats were also observed (p < 0.05). In BPA-exposed pregnant rats, miR-499-5p was significantly altered in the heart (p < 0.01). Meanwhile, altered miR-17-5p, -208-3p, and -210-3p expressions were observed in all heart of the foetuses from BPA-exposed pregnant rats (p < 0.05). In H&E staining, BPA-exposed foetal hearts showed a sign of fibrosis while BPA-exposed pregnant rats showed muscle remnant. Masson trichrome staining further confirmed the presence of fibrosis observed in BPA-exposed foetal heart and reduced expression of cardiac troponin I (cTnI) was also observed in BPA-exposed foetal heart. In summary, altered cardiac miRNAs with histological changes were observed in both mother- and foetus-exposed BPA These findings put forward the importance of future work to further understand how prenatal BPA exposure affect foetuses in their later stage of life