Polyethersulfone membrane biohybrid system using pig hepatocytes: Effect of diclofenac on cell biotransformation and synthetic functions

Metabolism of the aquatic pollutant diclofenac in the Lymnaea stagnalis freshwater gastropod

The metabolism of organic contaminants in Lymnaea stagnalis freshwater gastropod remains unknown. Yet, pharmaceuticals-like the NSAID diclofenac-are continuously released in the aquatic environment, thereby representing a risk to aquatic organisms. In addition, lower invertebrates may be affected by this pollution since they are likely to bioaccumulate contaminants. The metabolism of pharmaceuticals in L. stagnalis requires further investigation to understand their detoxification mechanisms and characterized the risk posed by contaminant exposure in this species. In this study, a non-targeted strategy using liquid chromatography combined with high-resolution mass spectrometry was applied to highlight metabolites formed in L. stagnalis freshwater snails exposed to 300 µg/L diclofenac for 3 and 7 days. Nineteen metabolites were revealed by this approach, 12 of which were observed for the first time in an aquatic organism exposed to diclofenac. Phase I metabolism involved hydroxylation, with detection of 3'-, 4'-, and 5-hydroxydiclofenac and three dihydroxylated metabolites, as well as cyclization, oxidative decarboxylation, and dehydrogenation, while phase II metabolism consisted of glucose and sulfate conjugation. Among these reactions, the two main DCF detoxification pathways detected in L. stagnalis were hydroxylation (phase I) and glucosidation (phase II).

Occurrence, interactive effects and ecological risk of diclofenac in environmental compartments and biota - a review

Diclofenac, a nonsteroidal anti-inflammatory drug has turned into a contaminant of emerging concern; hence, it was included in the previous Watch List of the EU Water Framework Directive. This review paper aims to highlight the metabolism of diclofenac at different trophic levels, its occurrence, ecological risks, and interactive effects in the water cycle and biota over the past two decades. Increased exposure to diclofenac not only raises health concerns for vultures, aquatic organisms, and higher plants but also causes serious threats to mammals. The ubiquitous nature of diclofenac in surface water (river, lake canal, estuary, and sea) is compared with drinking water, groundwater, and wastewater effluent in the environment. This comprehensive survey from previous studies suggests the fate of diclofenac in wastewater treatment plants (WWTPs) and may predict its persistence in the environment. This review offers evidence of fragmentary available data for the water environment, soil, sediment, and biota worldwide and supports the need for further data to address the risks associated with the presence of diclofenac in the environment. Finally, we suggest that the presence of diclofenac and its metabolites in the environment may represent a high risk because of their synergistic interactions with existing contaminants, leading to the development of drug-resistant strains and the formation of newly emerging pollutants.

Porcine hepatocytes culture on biofunctionalized 3D inverted colloidal crystal scaffolds as an in vitro model for predicting drug hepatotoxicity

As drug-induced hepatotoxicity represents one of the most common causes of drug failure, three-dimensional (3D) in vitro liver platforms represent a fantastic toolbox to predict drug toxicity and thus reduce in vivo animal studies and lessen drug attrition rates. The aim of this study is to establish a functional porcine hepatocyte culture using a biofunctionalized 3D inverted colloidal crystal (ICC) hydrogel platform. The performances of non-adhesive bare poly(ethylene glycol)diacrylate (PEGDA) ICCs and PEGDA ICCs coated with either collagen type I or fibronectin have been investigated. Porcine hepatocytes viability, morphology, hepatic-specific functions and patterns of gene expression have been evaluated over a period of two weeks in culture to test diclofenac, a well-known hepatotoxic drug. Interestingly, cells in the fibronectin-functionalized scaffold exhibit different aggregation patterns and maintain better liver-specific function than those in bare ICCs and in collagen functionalized scaffold. We concluded that the 3D cell culture environment and the presence of extracellular matrix (ECM) proteins, especially fibronectin, facilitate hepatocyte viability and maintenance of the liver-specific phenotype in vitro, and enable us to predict hepatotoxicity.

As drug-induced hepatotoxicity represents one of the most common causes of drug failure, three-dimensional in vitro liver platforms represent a fantastic toolbox to predict drug toxicity and reduce in vivo studies and drug attrition rates.

Neuroprotective effect of human mesenchymal stem cells in a compartmentalized neuronal membrane system

In this work, we describe the development of a compartmentalized membrane system using neonatal rodent hippocampal cells and human mesenchymal stem cells (hMSCs) to investigate the neuroprotective effects of hMSCs. To elucidate this interaction an in vitro oxygen-glucose deprivation (OGD) model was used that mimics central nervous system insults in vivo. Cells were cultured in a membrane system with a sandwich configuration in which the hippocampal cells were seeded on a fluorocarbon (FC) membrane, and were separated by hMSCs through a semipermeable polyethersulfone (PES) membrane that ensures the transport of molecules and paracrine factors, but prevents cell-to-cell contact. This system was used to simulate a cerebral ischemic damage by inducing OGD for 120min. The core contribution of the work highlights the neuroprotective effects of hMSCs on hippocampal cells in a membrane system for the first time. The novel results show that hMSC secretome factors protect hippocampal cells against OGD insults as indicated by the conservation of specific structural and functional cell features together with the development of a highly branched neural network after the damage. Moreover, neuronal cells co-cultured with hMSCs before OGD insult were able to maintain BDNF production and O2 consumption and did not express the apoptotic markers that were expressed in similarly insulted neuronal cells that had not been co-cultured with hMSCs. This compartmentalized membrane system appears to be a very useful and reliable system for studying the neuroprotective effects of hMSCs and identifying secreted factors that may be involved.

STATEMENT OF SIGNIFICANCE

This paper is based on a combined synergism of biomaterials technology and stem cell approach, focusing on the development of a compartmentalized membrane system that serves as an innovative tool for highlighting the role of hMSCs on hippocampal neurons upon damage. The membrane system consists of two different flat sheet membranes, giving rise to double and separated cell membrane compartments that prevent cell-to-cell contact but allow the transport of paracrine factors. This system strongly corroborates the paracrine mediated neuroprotection of hMSCs on ischemic damaged neurons. The challenging and pioneeristic approach by using biomaterials allowed to perform a stepwise analysis of the phenomena, providing new insights into the field of MSC therapy.

Direct synthesis of heparin-like poly(ether sulfone) polymer and its blood compatibility

In this study, heparin-like poly(ethersulfone) (HLPES) was synthesized by a combination of polycondensation and post-carboxylation methods, and was characterized by Fourier transform infrared spectroscopy, nuclear magnetic resonance hydrogen spectrum and gel permeation chromatography. Owing to the similar backbone structure, the synthesized HLPES could be directly blended with pristine PES at any ratios to prepare PES/HLPES membranes. After the introduction of HLPES, the microscopic structure of the modified PES membranes was changed, while the hydrophilicity was significantly enhanced. Bovine serum albumin and bovine serum fibrinogen adsorption, activated partial thromboplastin time, thromb time and platelet adhesion for the modified PES membranes were investigated. The results indicated that the blood compatibility of the PES/HLPES membranes was significantly improved compared with that of pristine PES membrane. For the PES/HLPES membranes, obvious decreases in platelet activation on PF-4 level, in complement activation on C3a and C5a levels, and in leukocytes activation on CD11b levels were observed compared with those for the pristine PES membrane. The improved blood compatibility of the PES/HLPES membrane might due to the existence of the hydrophilic groups (-SO3Na, -COONa). Furthermore, the modified PES membranes showed good cytocompatibility. Hepatocytes cultured on the PES/HLPES membranes presented improved growth in terms of SEM observation, MTT assay and confocal laser scanning microscope observation compared with those on the pristine PES membrane. These results indicate that the PES/HLPES membranes present great potential in blood-contact fields such as hemodialysis and bio-artificial liver supports.