Cellular models for studying the human urogenital system

The urogenital system is the organ system of the reproductive organs and the urinary system. These are grouped together because of their proximity to each other, their common embryological origin and the use of common pathways, like the male urethra.

Today, I’ll be taking a look at human primary cells derived from urogenital organs (and in one of my next posts, we’ll explore models for the digestive system.

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5 most popular posts in ADME-Tox in 2014!

Take a look at the 5 posts on our blog in the field of ADME-Tox that saw the most visits in 2014!

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Biomimetic Chemistry, a new route for metabolite synthesis

In 2008, the FDA released guidance for drug metabolite safety testing (MIST), emphasizing the importance of metabolite toxicity testing in the drug development process. Indeed, drug toxicity, which accounts for roughly 40% of clinical drug failures, is a leading cause of the high drug attrition rates that have contributed to the skyrocketing drug development costs witnessed over the past few decades.

Traditionally, drug metabolites have been both difficult and hugely expensive to synthesize. Conventional methods of metabolite synthesis, such as those that employ the use of microsomes (while they have proven valuable as a predictive tool, their productive capabilities could be limited by NCE stability) or synthetic chemistry, can be extremely costly and time consuming. Consequently, drugmakers often choose to forego metabolite synthesis (and subsequent metabolite toxicity testing ) early on in the drug development process, opting instead to wait until lead compounds are further along in development before carrying out these essential functions. This decision, perceived to be a calculated risk, ultimately comes at huge price, as drug makers lose millions each year on investments in lead drug candidates that eventually turn out to be failures due to toxicity.

Biomimetic Chemistry, on the other hand, possesses the advantages of both chemistry and biology and is thus a much more efficient tool for metabolite synthesis. In fact, with biomimetic chemistry, large scale metabolite generation is enabled in one step, by mimicking and optimizing the same biotransformation reactions that occur in the liver. [Read more…]

Comparison of XenoTech Hepatocytes to HepaRG® Cell Line

Metabolite formation for Diclofenac (2C9) and Midazolam (3A4) in XenoTech tebu-bio Cryostax pool of 5Oral drugs typically require effective half lives in the region of 10 – 20 h for once or twice daily dosing. For candidate drugs with low distribution volumes it’s necessary to define intrinsic clearance (CLint) values of 0.1 – 1µL/min/million human hepatocytes (Grime et al., 2013). Svanberg & co-workers wanted to compare in vitro systems that potentially can provide a solution to the problem of robustly defining low CLint values in human hepatocytes. Recently the HepatoPac™ Platform and a novel relay suspension method (Di et al., 2012) have shown promising results producing reliable low CLint values. XenoTech have made a well characterised platable pool of cryopreserved human hepatocytes (5 donors) commercially available (CryostaX+), which makes plated hepatocyte methods attractive to evaluate. Also of interest is the HepaRG® human hepatoma cell line, since it offers stable expression of drug metabolising enzymes (DMEs) (Kanebratt et al., 2008, Aninat et al., 2006).

The authors evaluate all four methods but this poster focuses on HepaRG & plated primary hepatocytes, since data from Hepatopac and Relay at present are inconclusive.

“Determination of Low Intrinsic Clearance Values using Primary Human Hepatocytes and the HepaRG® Cell Line – A Comparison of Methods”
Svanberg, et al – AstraZeneca R&D

Contact jean-francois.tetu @ tebu-bio.com to get your own copy of this poster.

Plateable Hepatocytes… the “one cell type doesn’t fit all” syndrome

Hepatocytes are commonly used in drug discovery and preclinical drug development to perform experiments requiring intact cellular systems. Intact hepatocytes contain the major hepatic drug-metabolizing enzymes required to study the four categories of xenobiotic biotransformation: Hydrolysis, Reduction, Oxidation and Conjugation. Because of these enzymes, hepatocytes provide a viable and cost-effective alternative to in vivo compound testings.

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Modulate hepatic inflammation

Kupffer cells are macrophages endogenous to the liver which have the ability to modulate hepatic inflammation and injury associated with various pathophysiologies and toxicities. Pro-inflammatory cytokines released by activated Kupffer cells, such as TNF-α and IL-6, are associated with up-regulation of acute-phase response proteins and suppression of CYP enzymes.

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6 tips for thawing hepatocytes

Cryopreserved hepatocytes contain the major hepatic drug-metabolizing enzymes required to study the four categories of xenobiotic biotransformation: hydrolysis, reduction, oxidation and conjugation. Cryopreserved hepatocytes are ready when you are. A simply quick-thaw protocol is performed to remove cryoprotectant and have viable cells… However, the functionality and the viability of these cells can be impaired by an incorrect thawing procedure… [Read more…]

Maximise availability & reduce variability in hepatocytes studies

ADMEPooled human hepatocytes are a preferred test system in many drug discovery and development applications which require intact cellular systems for in vitro testing. Intact hepatocytes contain the major hepatic drug-metabolizing enzymes and co-factors required to evaluate the metabolism and potential drug-drug interactions of drug candidates effectively.

Over the last decade, improvements of cryopreservation technologies make possible using cryopreserved human hepatocyte more conveniently. Pooled cryopreserved hepatocytes reduce the inter-individual differences and polymorphic distribution of liver enzymes. However, this is crucial to carefully select a pool according to its performance but also the application used for. [Read more…]

Evaluating Clearance by Aldehyde Oxidase (AO): The Impact of Low Versus High AO Activity

An interesting poster has recently been published by XenoTech: “Selection of Human Liver S9 and Cytosol Fractions for Evaluating Clearance by Aldehyde Oxidase (AO): The Impact of Low Versus High AO Activity Lots” by Phyllis Yerino, Clayton Otwell, Zell Woodworth and David B Buckley (XenoTech, LLC, Lenexa, KS, USA). [Read more…]

in vitro exploration of hepatobiliary drug disposition

What is an integrated hepatic model and why is it important?

An integrated in vitro model maintains physiologic cellular components and processes at in vivo-relevant amounts. In the sandwich-cultured hepatocyte model, relevant drug transporter proteins (uptake and efflux), as well as drug metabolizing enzymes (Phase I and II), are expressed, maintained, and functioning together in the same system. The figure below graphically represents this concept (picture from Qualyst Transporter Solutions). [Read more…]