Publications by authors named "Robert Sprando"

There is limited information on interactions between cannabinoids and many pharmacologically and toxicologically relevant targets in humans (e.g., receptors, ion channels, enzymes, and transporters).

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Consumer use of cannabidiol (CBD) is growing, but there are still data gaps regarding its possible adverse effects on reproduction and development. Multiple pathways and signaling cascades involved in organismal development and neuronal function, including endocannabinoid synthesis and signaling systems, are well conserved across phyla, suggesting that can model the effects of exogenous cannabinoids. The effects in on oxidative stress response (OxStrR), developmental timing, juvenile and adult spontaneous locomotor activity, reproductive output, and organismal CBD concentrations were assessed after exposure to purified CBD or a hemp extract suspended in 0.

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Article Synopsis
  • The worm Development and Activity Test (wDAT) uses the model organism C. elegans to assess developmental milestones and spontaneous locomotor activity, identifying impacts of various toxicants like arsenic and lead.
  • The wDAT found that certain teratogenic chemicals (5-fluorouracil, hydroxyurea, and ribavirin) caused developmental delays and altered activity levels in C. elegans, paralleling mammalian development impacts.
  • While the wDAT shows promise for recognizing developmental toxicants, further studies with more controls are needed to enhance its reliability and effectiveness for broader toxicity assessments.
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Since the passage of the 2018 Agriculture Improvement Act (2018 Farm Bill), the number of products containing cannabis-derived compounds available to consumers have rapidly increased. Potential effects on liver function as a result from consumption of products containing cannabidiol (CBD), including hemp extracts, have been observed but the mechanisms for the effects are not fully understood. In this study, hepatocytes derived from human induced pluripotent stem cells (iPSCs) were used to evaluate potential hepatic effects of CBD and hemp extract at exposure concentrations ranging from 0.

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Cannabidiol (CBD) has been reported to induce hepatotoxicity in clinical trials and research studies; however, little is known about the safety of other nonintoxicating cannabinoids. New approach methodologies (NAMs) based on bioinformatic analysis of high-throughput transcriptomic data are gaining increasing importance in risk assessment and regulatory decision-making of data-poor chemicals. In the current study, we conducted a concentration response transcriptomic analysis of hemp extract and its four major constituent cannabinoids [CBD, cannabichromene (CBC), cannabigerol (CBG), and cannabinol (CBN)] in hepatocytes derived from human induced pluripotent stem cells (iPSCs).

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Hemp extracts and consumer products containing cannabidiol (CBD) and/or other phytocannabinoids derived from hemp have entered the marketplace in recent years. CBD is an approved drug in the United States for the treatment of certain seizure disorders. While effects of CBD in the liver have been well characterized, data on the effects of other cannabinoids and hemp extracts in the liver and methods for studying these effects in vitro are limited.

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Despite two decades of research on silver nanoparticle (AgNP) toxicity, a safe threshold for exposure has not yet been established, albeit being critically needed for risk assessment and regulatory decision-making. Traditionally, a point-of-departure (PoD) value is derived from dose response of apical endpoints in animal studies using either the no-observed-adverse-effect level (NOAEL) approach, or benchmark dose (BMD) modeling. To develop new approach methodologies (NAMs) to inform human risk assessment of AgNPs, we conducted a concentration response modeling of the transcriptomic changes in hepatocytes derived from human induced pluripotent stem cells (iPSCs) after being exposed to a wide range concentration (0.

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Dietary supplements containing usnic acid have been increasingly marketed for weight loss over the past decades, even though incidences of severe hepatotoxicity and acute liver failure due to their overuse have been reported. To date, the toxic mechanism of usnic acid-induced liver injury at the molecular level still remains to be fully elucidated. Here, we conducted a transcriptomic study on usnic acid using a novel in vitro hepatotoxicity model employing human induced pluripotent stem cell (iPSC)-derived hepatocytes.

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We have adapted a semiautomated method for tracking Caenorhabditis elegans spontaneous locomotor activity into a quantifiable assay by developing a sophisticated method for analyzing the time course of measured activity. The 16-h worm Adult Activity Test (wAAT) can be used to measure C. elegans activity levels for efficient screening for pharmacological and toxicity-induced effects.

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Variability in supply, paucity of donors and cellular instability under in vitro conditions have limited the application of primary human hepatocytes (PHHs) to hepatotoxicity testing. Therefore, alternative sources have been sought for functional liver cells. Many of the earlier in vitro hepatotoxicity studies were carried out using hepatoma-derived cell lines.

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Exposures to arsenic and mercury are known to pose significant threats to human health; however, the effects specific to organic vs. inorganic forms are not fully understood. () transparent cuticle, along with the conservation of key genetic pathways regulating developmental and reproductive toxicology (DART)-related processes such as germ stem cell renewal and differentiation, meiosis, and embryonic tissue differentiation and growth, support this model's potential to address the need for quicker and more dependable testing methods for DART hazard identification.

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Recently, there has been an increase in cannabis-derived products being marketed as foods, dietary supplements, and other consumer products. Cannabis contains over a hundred cannabinoids, many of which have unknown physiological effects. Since there are large numbers of cannabinoids, and many are not commercially available for in vitro testing, an in silico tool (Chemotargets Clarity software) was used to predict binding between 55 cannabinoids and 4,799 biological targets (enzymes, ion channels, receptors, and transporters).

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Several cannabinoids (cannabidivarin (CBDV), cannabigerol (CBG), cannabidiol (CBD), cannabinol (CBN) and cannabichromene (CBC)) and ethanol hemp extract are being used in primary human hepatocytes (PHH), Caenorhabditis elegans (C. elegans) and in vitro buccal membrane absorption models to elucidate their potential toxicological mechanisms, evaluate their oromucosal absorption, and to identify their metabolites. William's E medium, C.

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Picamilon is an analogue of the neurotransmitter γ-aminobutyric acid (GABA), which is marketed as a nootropic claiming to enhance cognition. There is a lack of in silico, in vitro and in vivo data on the safety of picamilon. Therefore, to ascertain potential physiological effects of picamilon, it was screened against 50 safety-related biological targets (receptors, ion channels, enzymes and transporters) by in silico and in vitro methods.

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There has been an increased public interest in developing consumer products containing nonintoxicating cannabinoids, such as cannabidiol (CBD) and cannabigerol (CBG). At the present time, there is limited information available on the pharmacokinetics of cannabinoids in humans. Since pharmacokinetic profiles are important in understanding the pharmacological and toxicological effects at the target sites, physiologically based pharmacokinetic (PBPK) modeling was used to predict the plasma and tissue concentrations of 17 cannabinoids in humans.

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A variety of methods have been reported for the differentiation of hepatocyte-like cells (HLCs) from human induced pluripotent stem cells (iPSCs) using various growth factors or small molecules. However, direct comparison of the differentiation efficiency and the quality of the final HLCs between different methods has rarely been reported. To fill this data gap, we compared two hepatocyte differentiation methods, termed Method 1 and Method 2, and published the major findings in a research article entitled "Phenotypical, functional and transcriptomic comparison of two modified methods of hepatocyte differentiation from human induced pluripotent stem cells" (Li et al.

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Exposures to mercury and arsenic are known to pose significant threats to human health. Effects specific to organic vs. inorganic forms of these toxic elements are less understood however, especially for organic dimethylarsinic acid (DMA), which has recently been detected in pups of rodent dams orally exposed to inorganic sodium (meta)arsenite (NaAsO2).

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Hepatocyte-like cells (HLCs) generated from human induced pluripotent stem cells (iPSCs) could provide an unlimited source of liver cells for regenerative medicine, disease modeling, drug screening, and toxicology studies. Here we describe a stepwise improved protocol that enables highly efficient, homogeneous, and reproducible differentiation of human iPSCs into functional hepatocytes through controlling all three stages of hepatocyte differentiation, starting from a single cell (non-colony) culture of iPSCs, through homogeneous definitive endoderm induction and highly efficient hepatic specification, and finally arriving at matured HLCs. The final population of cells exhibits morphology closely resembling that of primary human hepatocytes, and expresses specific hepatic markers as evidenced by immunocytochemical staining.

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Human induced pluripotent stem cells (iPSCs) hold great promise for biomedical applications. However, establishment of new iPSC lines still presents many challenges. Here we describe a simple yet highly efficient two-step protocol for the isolation and purification of human iPSC lines.

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Directed differentiation of human induced pluripotent stem cells (iPSCs) into hepatocytes could provide an unlimited source of liver cells, and therefore holds great promise for regenerative medicine, disease modeling, drug screening and toxicology studies. Various methods have been established during the past decade to differentiate human iPSCs into hepatocyte-like cells (HLCs) using growth factors and/or small molecules. However, direct comparison of the differentiation efficiency and the quality of the final HLCs between different methods has rarely been reported.

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Microphysiological systems (MPS), such as organ-on-a-chip platforms, are an emerging alternative model that may be useful for predicting human physiology and/or toxicity. Due to the interest in these platforms, the Center for Food Safety and Applied Nutrition partnered with Emulate to evaluate the utility of the Beta Human Liver Emulation System (BHLES) for its regulatory science program. Using known hepatotoxic compounds (usnic acid, benzbromarone, tamoxifen, and acetaminophen) and compounds that have no reported human cases of liver toxicity (dimethyl sulfoxide, theophylline, and aminohippurate) the platform's performance was evaluated.

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Silver nanoparticles (AgNPs) have been increasingly used in a variety of consumer products over the last decades. However, their potential adverse effects have not been fully understood. In a previous study, we characterized transcriptomic changes in human induced pluripotent stem cell (iPSC)-derived hepatocyte-like cells (HLCs) in response to AgNP exposure.

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Induced pluripotent stem cells (iPSCs) offer the potential to generate tissue cells with donor diversity therefore promising to have widespread applications in regenerative medicine, disease modeling, drug discovery, and toxicity testing. Several somatic cell types have been utilized, with varying efficiencies, as source cells for the reprogramming of iPSCs. Recently, it has been reported that endothelial progenitor cells (EPCs) derived from umbilical cord blood (CB) or adult peripheral blood (PB) afford a practical and efficient cellular substrate for iPSC generation, and possess several advantages over other cell types.

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Toxicant exposure can induce acute or chronic alterations in cellular numbers, morphology, and cell function. The quantification of these parameters can provide valuable information regarding a toxicant's effect and/or mechanism of action in organ-on-a-chip toxicity testing platforms. Unfortunately, manual quantification can be variable and time consuming.

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3-Monochloropropane-1,2-diol (3-MCPD) is a food processing contaminant in some infant formula products and other foods in the United States. Although rodent studies have demonstrated that 3-MCPD and its palmitic esters have the potential to induce nephrotoxicity, our recent human cell culture studies using the human renal proximal tubule cell line HK-2 have not strongly supported this finding. Considering this disparity, we sought to examine whether changes in transporter gene expression on proximal tubule cells could be modulated by these compounds and allow us to glean mechanistic information on a possible indirect path to proximal tubule injury .

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